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Sample records for automatic multiple-zone rigid-body

  1. SYMBOD - A computer program for the automatic generation of symbolic equations of motion for systems of hinge-connected rigid bodies

    NASA Technical Reports Server (NTRS)

    Macala, G. A.

    1983-01-01

    A computer program is described that can automatically generate symbolic equations of motion for systems of hinge-connected rigid bodies with tree topologies. The dynamical formulation underlying the program is outlined, and examples are given to show how a symbolic language is used to code the formulation. The program is applied to generate the equations of motion for a four-body model of the Galileo spacecraft. The resulting equations are shown to be a factor of three faster in execution time than conventional numerical subroutines.

  2. Kinematic problem of rigid body orientation control

    NASA Astrophysics Data System (ADS)

    Plotnikov, P. K.; Sergeev, A. N.; Chelnokov, Iu. N.

    1991-10-01

    The problem of reducing a coordinate system linked with a rigid body to a reference coordinate system rotating with a specified (programmed) angular velocity is analyzed using a kinematic formulation. The mathematic model of motion includes kinematic equations of the angular motion of a rigid body in nonnormalized quaternions; used as the controls are projections of the absolute angular velocity of body rotation to the coordinate axes. Two kinds of correction are proposed which represent quaternion analogs of the positional and integral corrections. Linear error equations for the orientation control system are obtained for the types of correction proposed here.

  3. Quantum mechanics of a generalised rigid body

    NASA Astrophysics Data System (ADS)

    Gripaios, Ben; Sutherland, Dave

    2016-05-01

    We consider the quantum version of Arnold’s generalisation of a rigid body in classical mechanics. Thus, we quantise the motion on an arbitrary Lie group manifold of a particle whose classical trajectories correspond to the geodesics of any one-sided-invariant metric. We show how the derivation of the spectrum of energy eigenstates can be simplified by making use of automorphisms of the Lie algebra and (for groups of type I) by methods of harmonic analysis. We show how the method can be extended to cosets, generalising the linear rigid rotor. As examples, we consider all connected and simply connected Lie groups up to dimension 3. This includes the universal cover of the archetypical rigid body, along with a number of new exactly solvable models. We also discuss a possible application to the topical problem of quantising a perfect fluid.

  4. Optimizing Simulated Trajectories Of Rigid Bodies

    NASA Technical Reports Server (NTRS)

    Brauer, Garry L.; Olson, David W.; Stevenson, Robert

    1989-01-01

    6D POST is general-purpose, six-degree-of-freedom computer program for optimization of simulated trajectories of rigid bodies. Direct extension of three-degree-of-freedom POST program. 6D POST program models trajectory of powered or unpowered vehicle operating at or near rotating planet. Used to solve variety of performance, guidance, and flight-control problems for atmospheric and orbital vehicles. Written in FORTRAN 77 and FORTRAN V.

  5. Langevin thermostat for rigid body dynamics.

    PubMed

    Davidchack, Ruslan L; Handel, Richard; Tretyakov, M V

    2009-06-21

    We present a new method for isothermal rigid body simulations using the quaternion representation and Langevin dynamics. It can be combined with the traditional Langevin or gradient (Brownian) dynamics for the translational degrees of freedom to correctly sample the canonical distribution in a simulation of rigid molecules. We propose simple, quasisymplectic second-order numerical integrators and test their performance on the TIP4P model of water. We also investigate the optimal choice of thermostat parameters.

  6. New Langevin and gradient thermostats for rigid body dynamics.

    PubMed

    Davidchack, R L; Ouldridge, T E; Tretyakov, M V

    2015-04-14

    We introduce two new thermostats, one of Langevin type and one of gradient (Brownian) type, for rigid body dynamics. We formulate rotation using the quaternion representation of angular coordinates; both thermostats preserve the unit length of quaternions. The Langevin thermostat also ensures that the conjugate angular momenta stay within the tangent space of the quaternion coordinates, as required by the Hamiltonian dynamics of rigid bodies. We have constructed three geometric numerical integrators for the Langevin thermostat and one for the gradient thermostat. The numerical integrators reflect key properties of the thermostats themselves. Namely, they all preserve the unit length of quaternions, automatically, without the need of a projection onto the unit sphere. The Langevin integrators also ensure that the angular momenta remain within the tangent space of the quaternion coordinates. The Langevin integrators are quasi-symplectic and of weak order two. The numerical method for the gradient thermostat is of weak order one. Its construction exploits ideas of Lie-group type integrators for differential equations on manifolds. We numerically compare the discretization errors of the Langevin integrators, as well as the efficiency of the gradient integrator compared to the Langevin ones when used in the simulation of rigid TIP4P water model with smoothly truncated electrostatic interactions. We observe that the gradient integrator is computationally less efficient than the Langevin integrators. We also compare the relative accuracy of the Langevin integrators in evaluating various static quantities and give recommendations as to the choice of an appropriate integrator.

  7. Pulling rigid bodies through granular material

    NASA Astrophysics Data System (ADS)

    Kubik, Ryan; Dressaire, Emilie

    2016-11-01

    The need for anchoring systems in granular materials such as sand is present in the marine transportation industry, e.g. to layout moorings, keep vessels and docks fixed in bodies of water, build oil rigs, etc. The holding power of an anchor is associated with the force exerted by the granular media. Empirical evidence indicates that the holding power depends on the size and shape of the anchoring structure. In this model study, we use a two-dimensional geometry in which a rigid body is pulled through a granular media at constant velocity to determine the drag and lift forces exerted by a granular medium on a moving object. The method allows measuring the drag force and recording the trajectory of the rigid object through the sand. We systematically vary the size and geometry of the rigid body, the properties of the granular medium and the extraction speed. For different initial positions of a cylindrical object pulled horizontally through the medium, we record large variations in magnitude of the drag and a significant lift force that pulls the object out of the sand.

  8. Understanding rigid body motion in arbitrary dimensions

    NASA Astrophysics Data System (ADS)

    Leyvraz, Francois

    2015-05-01

    Why would anyone wish to generalize the already unappetizing subject of rigid body motion to an arbitrary number of dimensions? At first sight, the subject seems to be both repellent and superfluous. The author will try to argue that an approach involving no specific three-dimensional constructs is actually easier to grasp than the traditional approach and might thus be generally useful to understand rigid body motion both in three dimensions and in the general case. Specific differences between the viewpoint suggested here and the usual one include the following: here angular velocities are systematically treated as antisymmetric matrices, a symmetric tensor I quite different from the moment of inertia tensor plays a central role, whereas the latter is shown to be a far more complex object, namely a tensor of rank four. A straightforward way to define it is given. The Euler equation is derived and the use of Noether’s theorem to obtain conserved quantities is illustrated. Finally the equations of motion for a heavy top as well as for two bodies linked by a spherical joint are derived to display the simplicity and the power of the method.

  9. Fast Collision Detection for Fracturing Rigid Bodies.

    PubMed

    Glondu, Loeiz; Schvartzman, Sara C; Marchal, Maud; Dumont, Georges; Otaduy, Miguel A

    2013-07-03

    In complex scenes with many objects, collision detection plays a key role in the simulation performance. This is particularly true in fracture simulation for two main reasons. One is that fracture fragments tend to exhibit very intensive contact, and the other is that collision detection data structures for new fragments need to be computed on the fly. In this paper, we present novel collision detection algorithms and data structures for real-time simulation of fracturing rigid bodies. We build on a combination of well-known efficient data structures, namely distance fields and sphere trees, making our algorithm easy to integrate on existing simulation engines. We propose novel methods to construct these data structures, such that they can be efficiently updated upon fracture events and integrated in a simple yet effective self-adapting contact selection algorithm. Altogether, we drastically reduce the cost of both collision detection and collision response. We have evaluated our global solution for collision detection on challenging scenarios, achieving high frame rates suited for hard real-time applications such as video games or haptics. Our solution opens promising perspectives for complex fracture simulations involving many dynamically created rigid objects.

  10. Fast collision detection for fracturing rigid bodies.

    PubMed

    Glondu, Loeiz; Schvartzman, Sara C; Marchal, Maud; Dumont, Georges; Otaduy, Miguel A

    2014-01-01

    In complex scenes with many objects, collision detection plays a key role in the simulation performance. This is particularly true in fracture simulation for two main reasons. One is that fracture fragments tend to exhibit very intensive contact, and the other is that collision detection data structures for new fragments need to be computed on the fly. In this paper, we present novel collision detection algorithms and data structures for real-time simulation of fracturing rigid bodies. We build on a combination of well-known efficient data structures, namely, distance fields and sphere trees, making our algorithm easy to integrate on existing simulation engines. We propose novel methods to construct these data structures, such that they can be efficiently updated upon fracture events and integrated in a simple yet effective self-adapting contact selection algorithm. Altogether, we drastically reduce the cost of both collision detection and collision response. We have evaluated our global solution for collision detection on challenging scenarios, achieving high frame rates suited for hard real-time applications such as video games or haptics. Our solution opens promising perspectives for complex fracture simulations involving many dynamically created rigid objects.

  11. Rigid Body Motion in Stereo 3D Simulation

    ERIC Educational Resources Information Center

    Zabunov, Svetoslav

    2010-01-01

    This paper addresses the difficulties experienced by first-grade students studying rigid body motion at Sofia University. Most quantities describing the rigid body are in relations that the students find hard to visualize and understand. They also lose the notion of cause-result relations between vector quantities, such as the relation between…

  12. Stochastic modeling of uncertain mass characteristics in rigid body dynamics

    NASA Astrophysics Data System (ADS)

    Richter, Lanae A.; Mignolet, Marc P.

    2017-03-01

    This paper focuses on the formulation, assessment, and application of a modeling strategy of uncertainty on the mass characteristics of rigid bodies, i.e. mass, position of center of mass, and inertia tensor. These characteristics are regrouped into a 4×4 matrix the elements of which are represented as random variables with joint probability density function derived following the maximum entropy framework. This stochastic model is first shown to satisfy all properties expected of the mass and tensor of inertia of rigid bodies. Its usefulness and computational efficiency are next demonstrated on the behavior of a rigid body in pure rotation exhibiting significant uncertainty in mass distribution.

  13. Modeling the Collision with Friction of Rigid Bodies

    NASA Astrophysics Data System (ADS)

    Zabuga, A. G.

    2016-09-01

    Different models of a perfectly inelastic collision of rigid bodies in plane motion are compared. Formulas for the impact impulses are derived for the Kane-Levinson-Whittaker model based on the kinematic restitution factor, the Routh model based on the kinetic restitution factor, and the Stronge model based on the energy restitution factor. It is shown that these formulas coincide if the collision of rough rigid bodies in plane motion is perfectly inelastic

  14. Interaction between a flexible filament and a downstream rigid body

    NASA Astrophysics Data System (ADS)

    Tian, Fang-Bao; Luo, Haoxiang; Zhu, Luoding; Lu, Xi-Yun

    2010-08-01

    A filament flapping in the bow wake of a rigid body is considered in order to study the hydrodynamic interaction between flexible and rigid bodies in tandem arrangement. Both numerical and experimental methods are adopted to analyze the motion of the filament, and the drag force on both bodies is computed. It is shown that the results largely depend on the gap between the two objects and the Reynolds number. The flexible body may have larger vibration amplitude but meanwhile experience a reduced drag force. On the other hand, the trailing rigid body enjoys a drag reduction. The qualitative behavior of the filament is independent of the filament’s length and mass ratio or the shape of the rigid body for the parameter regime considered. The result is in contrast with the interaction between two rigid or two flexible objects in tandem arrangement, and it may provide a physical insight into the understanding of the aquatic animals swimming in the bow wake of ships or staying in the bow wake of stationary structures.

  15. Integrability of two interactingN-dimensional rigid bodies

    NASA Astrophysics Data System (ADS)

    Perelomov, A. M.; Ragnisco, O.; Wojciechowski, S.

    1985-12-01

    A new class of integrable Euler equations on the Lie algebra so(2n) describing twon-dimensional interacting rigid bodies is found. A Lax representation of equations of motion which depends on a spectral parameter is given and complete integrability is proved. The double hamiltonian structure and the Lax representation of the general flow is discussed.

  16. Knowledge-In-Action: An Example with Rigid Body Motion

    ERIC Educational Resources Information Center

    Da Costa, Sayonara Salvador Cabral; Moreira, Marco Antonio

    2005-01-01

    This paper reports the analysis of the resolution of a paper-and-pencil problem, by eight undergraduate students majoring in engineering (six) and physics (two) at the Pontifcia Universidade Catlica do Rio Grande do Sul, in Porto Alegre, Brazil. The problem concerns kinetics of a rigid body, and the analysis was done in the light of Johnson-Lairds…

  17. An Experiment on the Inertial Properties of a Rigid Body.

    ERIC Educational Resources Information Center

    Armstrong, H. L.

    1985-01-01

    Presents an experiment which focuses on the inertial properties of a rigid body as expressed in terms of principal axes and moments of inertia. Background information, a description of the apparatus needed, and a discussion of results obtained are included. (JN)

  18. Stability characterizations of fixtured rigid bodies with Coulomb friction

    SciTech Connect

    PANG,J.S.; TRINKLE,JEFFREY C.

    2000-02-15

    This paper formally introduces several stability characterizations of fixtured three-dimensional rigid bodies initially at rest and in unilateral contact with Coulomb friction. These characterizations, weak stability and strong stability, arise naturally from the dynamic model of the system, formulated as a complementarity problem. Using the tools of complementarity theory, these characterizations are studied in detail to understand their properties and to develop techniques to identify the stability classifications of general systems subjected to known external loads.

  19. Direct inversion of rigid-body rotational dynamics

    NASA Technical Reports Server (NTRS)

    Bach, Ralph; Paielli, Russell

    1990-01-01

    The global linearization (inversion) of rigid-body rotational dynamics is reviewed and representations in terms of quaternions and direction cosines are compared. Certain properties common to quaternions and direction cosines that make their use preferable to Euler angles and that simplify the inversion procedure are described. Applications of the inversion procedure for state estimation and attitude control are discussed. To avoid complexities caused by aerodynamics, an example of direct inversion for linear feedback control of spacecraft attitude is given.

  20. Direct inversion of rigid-body rotational dynamics

    NASA Technical Reports Server (NTRS)

    Bach, Ralph; Paielli, Russell

    1990-01-01

    The global linearization (inversion) of rigid-body rotational dynamics is reviewed, and representations in terms of quaternions and direction cosines are compared. Certain properties common to quaternions and direction cosines that make their use preferable to Euler angles and that simplify the inversion procedure are described. Applications of the inversion procedure for state estimation and attitude control are discussed. To avoid complexities caused by aerodynamics, an example of direct inversion for linear feedback control of spacecraft attitude is given.

  1. The two rigid body interaction using angular momentum theory formulae

    NASA Astrophysics Data System (ADS)

    Boué, Gwenaël

    2017-01-01

    This work presents an elegant formalism to model the evolution of the full two rigid body problem. The equations of motion, given in a Cartesian coordinate system, are expressed in terms of spherical harmonics and Wigner D-matrices. The algorithm benefits from the numerous recurrence relations satisfied by these functions allowing a fast evaluation of the mutual potential. Moreover, forces and torques are straightforwardly obtained by application of ladder operators taken from the angular momentum theory and commonly used in quantum mechanics. A numerical implementation of this algorithm is made. Tests show that the present code is significantly faster than those currently available in literature.

  2. Small Moving Rigid Body into a Viscous Incompressible Fluid

    NASA Astrophysics Data System (ADS)

    Lacave, Christophe; Takahashi, Takéo

    2017-03-01

    We consider a single disk moving under the influence of a two dimensional viscous fluid and we study the asymptotic as the size of the solid tends to zero. If the density of the solid is independent of ɛ, the energy equality is not sufficient to obtain a uniform estimate for the solid velocity. This will be achieved thanks to the optimal L p - L q decay estimates of the semigroup associated to the fluid-rigid body system and to a fixed point argument. Next, we will deduce the convergence to the solution of the Navier-Stokes equations in R2.

  3. Plane stress problems using hysteretic rigid body spring network models

    NASA Astrophysics Data System (ADS)

    Christos, Sofianos D.; Vlasis, Koumousis K.

    2016-08-01

    In this work, a discrete numerical scheme is presented capable of modeling the hysteretic behavior of 2D structures. Rigid Body Spring Network (RBSN) models that were first proposed by Kawai (Nucl Eng Des 48(1):29-207, 1978) are extended to account for hysteretic elastoplastic behavior. Discretization is based on Voronoi tessellation, as proposed specifically for RBSN models to ensure uniformity. As a result, the structure is discretized into convex polygons that form the discrete rigid bodies of the model. These are connected with three zero length, i.e., single-node springs in the middle of their common facets. The springs follow the smooth hysteretic Bouc-Wen model which efficiently incorporates classical plasticity with no direct reference to a yield surface. Numerical results for both static and dynamic loadings are presented, which validate the proposed simplified spring-mass formulation. In addition, they verify the model's applicability on determining primarily the displacement field and plastic zones compared to the standard elastoplastic finite element method.

  4. A method for measuring the inertia properties of rigid bodies

    NASA Astrophysics Data System (ADS)

    Gobbi, M.; Mastinu, G.; Previati, G.

    2011-01-01

    A method for the measurement of the inertia properties of rigid bodies is presented. Given a rigid body and its mass, the method allows to measure (identify) the centre of gravity location and the inertia tensor during a single test. The proposed technique is based on the analysis of the free motion of a multi-cable pendulum to which the body under consideration is connected. The motion of the pendulum and the forces acting on the system are recorded and the inertia properties are identified by means of a proper mathematical procedure based on a least square estimation. After the body is positioned on the test rig, the full identification procedure takes less than 10 min. The natural frequencies of the pendulum and the accelerations involved are quite low, making this method suitable for many practical applications. In this paper, the proposed method is described and two test rigs are presented: the first is developed for bodies up to 3500 kg and the second for bodies up to 400 kg. A validation of the measurement method is performed with satisfactory results. The test rig holds a third part quality certificate according to an ISO 9001 standard and could be scaled up to measure the inertia properties of huge bodies, such as trucks, airplanes or even ships.

  5. Computational Fluid Dynamics Demonstration of Rigid Bodies in Motion

    NASA Technical Reports Server (NTRS)

    Camarena, Ernesto; Vu, Bruce T.

    2011-01-01

    The Design Analysis Branch (NE-Ml) at the Kennedy Space Center has not had the ability to accurately couple Rigid Body Dynamics (RBD) and Computational Fluid Dynamics (CFD). OVERFLOW-D is a flow solver that has been developed by NASA to have the capability to analyze and simulate dynamic motions with up to six Degrees of Freedom (6-DOF). Two simulations were prepared over the course of the internship to demonstrate 6DOF motion of rigid bodies under aerodynamic loading. The geometries in the simulations were based on a conceptual Space Launch System (SLS). The first simulation that was prepared and computed was the motion of a Solid Rocket Booster (SRB) as it separates from its core stage. To reduce computational time during the development of the simulation, only half of the physical domain with respect to the symmetry plane was simulated. Then a full solution was prepared and computed. The second simulation was a model of the SLS as it departs from a launch pad under a 20 knot crosswind. This simulation was reduced to Two Dimensions (2D) to reduce both preparation and computation time. By allowing 2-DOF for translations and 1-DOF for rotation, the simulation predicted unrealistic rotation. The simulation was then constrained to only allow translations.

  6. Dynamic simulation of articulated rigid bodies with contact and collision.

    PubMed

    Weinstein, Rachel; Teran, Joseph; Fedkiw, Ron

    2006-01-01

    We propose a novel approach for dynamically simulating articulated rigid bodies undergoing frequent and unpredictable contact and collision. In order to leverage existing algorithms for nonconvex bodies, multiple collisions, large contact groups, stacking, etc., we use maximal rather than generalized coordinates and take an impulse-based approach that allows us to treat articulation, contact, and collision in a unified manner. Traditional constraint handling methods are subject to drift, and we propose a novel prestabilization method that does not require tunable potentially stiff parameters as does Baumgarte stabilization. This differs from poststabilization in that we compute allowable trajectories before moving the rigid bodies to their new positions, instead of correcting them after the fact when it can be difficult to incorporate the effects of contact and collision. A poststabilization technique is used for momentum and angular momentum. Our approach works with any black box method for specifying valid joint constraints and no special considerations are required for arbitrary closed loops or branching. Moreover, our implementation is linear both in the number of bodies and in the number of auxiliary contact and collision constraints, unlike many other methods that are linear in the number of bodies, but not in the number of auxiliary constraints.

  7. Leonhard Euler and the mechanics of rigid bodies

    NASA Astrophysics Data System (ADS)

    Marquina, J. E.; Marquina, M. L.; Marquina, V.; Hernández-Gómez, J. J.

    2017-01-01

    In this work we present the original ideas and the construction of the rigid bodies theory realised by Leonhard Euler between 1738 and 1775. The number of treatises written by Euler on this subject is enormous, including the most notorious Scientia Navalis (1749), Decouverte d’un noveau principe de mecanique (1752), Du mouvement de rotation des corps solides autour d’un axe variable (1765), Theoria motus corporum solidorum seu rigidorum (1765) and Nova methodus motu corporum rigidorum determinandi (1776), in which he developed the ideas of the instantaneous rotation axis, the so-called Euler equations and angles, the components of what is now known as the inertia tensor, the principal axes of inertia, and, finally, the generalisation of the translation and rotation movement equations for any system. Euler, the man who ‘put most of mechanics into its modern form’ (Truesdell 1968 Essays in the History of Mechanics (Berlin: Springer) p 106).

  8. Normal mode study of the earth's rigid body motions

    NASA Technical Reports Server (NTRS)

    Chao, B. F.

    1983-01-01

    In this paper it is shown that the earth's rigid body (rb) motions can be represented by an analytical set of eigensolutions to the equation of motion for elastic-gravitational free oscillations. Thus each degree of freedom in the rb motion is associated with a rb normal mode. Cases of both nonrotating and rotating earth models are studied, and it is shown that the rb modes do incorporate neatly into the earth's system of normal modes of free oscillation. The excitation formula for the rb modes are also obtained, based on normal mode theory. Physical implications of the results are summarized and the fundamental differences between rb modes and seismic modes are emphasized. In particular, it is ascertained that the Chandler wobble, being one of the rb modes belonging to the rotating earth, can be studied using the established theory of normal modes.

  9. Hamiltonian Dynamics of Several Rigid Bodies Interacting with Point Vortices

    NASA Astrophysics Data System (ADS)

    Weißmann, Steffen

    2014-04-01

    We derive the dynamics of several rigid bodies of arbitrary shape in a two-dimensional inviscid and incompressible fluid, whose vorticity is given by point vortices. We adopt the idea of Vankerschaver et al. (J. Geom. Mech. 1(2): 223-226, 2009) to derive the Hamiltonian formulation via symplectic reduction from a canonical Hamiltonian system. The reduced system is described by a noncanonical symplectic form, which has previously been derived for a single circular disk using heavy differential-geometric machinery in an infinite-dimensional setting. In contrast, our derivation makes use of the fact that the dynamics of the fluid, and thus the point vortex dynamics, is determined from first principles. Using this knowledge we can directly determine the dynamics on the reduced, finite-dimensional phase space, using only classical mechanics. Furthermore, our approach easily handles several bodies of arbitrary shape. From the Hamiltonian description we derive a Lagrangian formulation, which enables the system for variational time integrators. We briefly describe how to implement such a numerical scheme and simulate different configurations for validation.

  10. Dynamical analysis of an orbiting three-rigid-body system

    SciTech Connect

    Pagnozzi, Daniele E-mail: james.biggs@strath.ac.uk; Biggs, James D. E-mail: james.biggs@strath.ac.uk

    2014-12-10

    The development of multi-joint-spacecraft mission concepts calls for a deeper understanding of their nonlinear dynamics to inform and enhance system design. This paper presents a study of a three-finite-shape rigid-body system under the action of an ideal central gravitational field. The aim of this paper is to gain an insight into the natural dynamics of this system. The Hamiltonian dynamics is derived and used to identify relative attitude equilibria of the system with respect to the orbital reference frame. Then a numerical investigation of the behaviour far from the equilibria is provided using tools from modern dynamical systems theory such as energy methods, phase portraits and Poincarè maps. Results reveal a complex structure of the dynamics as well as the existence of connections between some of the equilibria. Stable equilibrium configurations appear to be surrounded by very narrow regions of regular and quasi-regular motions. Trajectories evolve on chaotic motions in the rest of the domain.

  11. Uniqueness of the angular velocity of a rigid body: Correction of two faulty proofs

    NASA Astrophysics Data System (ADS)

    Lemos, Nivaldo A.

    2000-07-01

    The angular velocity is an absolute or intrinsic property of a rigid body; that is, all points of a rotating rigid body have the same angular velocity. This fact is well known, but its proof is often erroneous. Here we correct two faulty proofs of this result, one in Goldstein's famous textbook and the other published nearly 30 years ago in this journal.

  12. A general purpose nonlinear rigid body mass finite element for application to rotary wing dynamics

    NASA Technical Reports Server (NTRS)

    Hamilton, B. K.; Straub, F. K.; Ruzicka, G. C.

    1991-01-01

    The Second Generation Comprehensive Helicopter Analysis System employs the present formulation of the general-purpose nonlinear rigid body mass finite element, which represents the hub masses, blade tip masses, and pendulum vibration absorbers. The rigid body mass element has six degrees of freedom, and accounts for gravitational as well as dynamic effects. A consequence of deriving the element's equations from various physical principles is that, prior to the transformation which couples the rigid body mass element to the rotor blade finite element, the forces obtained for each element are fundamentally different; this is true notwithstanding the degrees-of-freedom of each element are parameterized using the same coordinates.

  13. Periodic contact between piezoelectric materials and a rigid body with a wavy surface

    NASA Astrophysics Data System (ADS)

    Zhou, Yue-Ting; Kim, Tae-Won

    2015-01-01

    An exact analysis is conducted for periodic, two-dimensional (2D) contact of piezoelectric materials in contact with a rigid body with a wavy surface pressed by uniform stresses at infinity. For three cases of eigenvalue distribution, three harmonic functions automatically satisfying the periodicity conditions are carefully constructed to facilitate the derivation of the solution of the considered problem. The stresses and electric displacements are obtained as infinite series. It is found that for the full contact case, the disturbance stress and electric displacement fields remain only the first harmonic which has the slowest decay in the y-direction. The convergence behaviours of the infinite series are checked, which shows that the external loading p and different positions have a great effect on the convergence behaviours of the infinite series and 400 terms are enough to get accurate solution at each position. Numerical results are presented to justify the validity of the present derivation and show the effect of the external loading on the contact behaviours.

  14. Acceleration analysis of multi-rigid body system and its application for vehicle based stabilized platform system

    NASA Astrophysics Data System (ADS)

    Liu, Xiao; Luo, Erjuan; Jia, Lei; Liu, Bo

    2017-01-01

    The traditional representation of acceleration of a rigid body is given in terms of the angular acceleration and linear acceleration of a point attached to the rigid body. Since this representation has no coordinate invariance, the acceleration transformation of a multi-rigid-body system is complicated. In this paper, the physical meaning of the time derivative of a twist is investigated. It reveals that the rigid-body acceleration comprises the angular acceleration and tangent acceleration of a point which is attached to the rigid body and instantaneously coincident with the origin of frame in use. Their composition presents a six-dimensional representation of the rigid-body acceleration, which is verified to be of coordinate invariance. Based on the representation, the transformation of the rigid-body accelerations is performed conveniently, and the corresponding formula of composition accelerations of one rigid body relative to any other bodies in a multi-rigid-body system is presented. The method is then extended to the application of a vehicle stabilized platform system. The method is verified to be effective by analyzing the virtual prototype of the vehicle-based stabilized platform system. This paper builds a bridge for the six-dimensional rigid-body acceleration from theory achievements to practical application.

  15. Attitude dynamics simulation subroutines for systems of hinge-connected rigid bodies with nonrigid appendages

    NASA Technical Reports Server (NTRS)

    Fleischer, G. E.; Likins, P. W.

    1975-01-01

    Three computer subroutines designed to solve the vector-dyadic differential equations of rotational motion for systems that may be idealized as a collection of hinge-connected rigid bodies assembled in a tree topology, with an optional flexible appendage attached to each body are reported. Deformations of the appendages are mathematically represented by modal coordinates and are assumed small. Within these constraints, the subroutines provide equation solutions for (1) the most general case of unrestricted hinge rotations, with appendage base bodies nominally rotating at a constant speed, (2) the case of unrestricted hinge rotations between rigid bodies, with the restriction that those rigid bodies carrying appendages are nominally nonspinning, and (3) the case of small hinge rotations and nominally nonrotating appendages. Sample problems and their solutions are presented to illustrate the utility of the computer programs.

  16. Virtual rigid body: a new optical tracking paradigm in image-guided interventions

    NASA Astrophysics Data System (ADS)

    Cheng, Alexis; Lee, David S.; Deshmukh, Nishikant; Boctor, Emad M.

    2015-03-01

    Tracking technology is often necessary for image-guided surgical interventions. Optical tracking is one the options, but it suffers from line of sight and workspace limitations. Optical tracking is accomplished by attaching a rigid body marker, having a pattern for pose detection, onto a tool or device. A larger rigid body results in more accurate tracking, but at the same time large size limits its usage in a crowded surgical workspace. This work presents a prototype of a novel optical tracking method using a virtual rigid body (VRB). We define the VRB as a 3D rigid body marker in the form of pattern on a surface generated from a light source. Its pose can be recovered by observing the projected pattern with a stereo-camera system. The rigid body's size is no longer physically limited as we can manufacture small size light sources. Conventional optical tracking also requires line of sight to the rigid body. VRB overcomes these limitations by detecting a pattern projected onto the surface. We can project the pattern onto a region of interest, allowing the pattern to always be in the view of the optical tracker. This helps to decrease the occurrence of occlusions. This manuscript describes the method and results compared with conventional optical tracking in an experiment setup using known motions. The experiments are done using an optical tracker and a linear-stage, resulting in targeting errors of 0.38mm+/-0.28mm with our method compared to 0.23mm+/-0.22mm with conventional optical markers. Another experiment that replaced the linear stage with a robot arm resulted in rotational errors of 0.50+/-0.31° and 2.68+/-2.20° and the translation errors of 0.18+/-0.10 mm and 0.03+/-0.02 mm respectively.

  17. Computing the Free Energy along a Reaction Coordinate Using Rigid Body Dynamics.

    PubMed

    Tao, Peng; Sodt, Alexander J; Shao, Yihan; König, Gerhard; Brooks, Bernard R

    2014-10-14

    The calculations of potential of mean force along complex chemical reactions or rare events pathways are of great interest because of their importance for many areas in chemistry, molecular biology, and material science. The major difficulty for free energy calculations comes from the great computational cost for adequate sampling of the system in high-energy regions, especially close to the reaction transition state. Here, we present a method, called FEG-RBD, in which the free energy gradients were obtained from rigid body dynamics simulations. Then the free energy gradients were integrated along a reference reaction pathway to calculate free energy profiles. In a given system, the reaction coordinates defining a subset of atoms (e.g., a solute, or the quantum mechanics (QM) region of a quantum mechanics/molecular mechanics simulation) are selected to form a rigid body during the simulation. The first-order derivatives (gradients) of the free energy with respect to the reaction coordinates are obtained through the integration of constraint forces within the rigid body. Each structure along the reference reaction path is separately subjected to such a rigid body simulation. The individual free energy gradients are integrated along the reference pathway to obtain the free energy profile. Test cases provided demonstrate both the strengths and weaknesses of the FEG-RBD method. The most significant benefit of this method comes from the fast convergence rate of the free energy gradient using rigid-body constraints instead of restraints. A correction to the free energy due to approximate relaxation of the rigid-body constraint is estimated and discussed. A comparison with umbrella sampling using a simple test case revealed the improved sampling efficiency of FEG-RBD by a factor of 4 on average. The enhanced efficiency makes this method effective for calculating the free energy of complex chemical reactions when the reaction coordinate can be unambiguously defined by a

  18. A comparative study of velocity increment generation between the rigid body and flexible models of MMET

    SciTech Connect

    Ismail, Norilmi Amilia

    2016-02-01

    The motorized momentum exchange tether (MMET) is capable of generating useful velocity increments through spin–orbit coupling. This study presents a comparative study of the velocity increments between the rigid body and flexible models of MMET. The equations of motions of both models in the time domain are transformed into a function of true anomaly. The equations of motion are integrated, and the responses in terms of the velocity increment of the rigid body and flexible models are compared and analysed. Results show that the initial conditions, eccentricity, and flexibility of the tether have significant effects on the velocity increments of the tether.

  19. A penalty immersed boundary method for a rigid body in fluid

    NASA Astrophysics Data System (ADS)

    Kim, Yongsam; Peskin, Charles S.

    2016-03-01

    We extend the penalty immersed boundary (pIB) method to the interaction between a rigid body and a surrounding fluid. The pIB method is based on the idea of splitting an immersed boundary, which here is a rigid body, notionally into two Lagrangian components: one is a massive component carrying all mass of the rigid body and the other is massless. These two components are connected by a system of stiff springs with 0 rest length. The massless component interacts with the surrounding fluid: it moves at the local fluid velocity and exerts force locally on the fluid. The massive component has no direct interaction with the surrounding fluid and behaves as though in a vacuum, following the dynamics of a rigid body, in which the acting forces and torques are generated from the system of stiff springs that connects the two Lagrangian components. We verify the pIB method by computing the drag coefficients of a cylinder and ball descending though a fluid under the influence of gravity and also by studying the interaction of two such descending cylinders and likewise the interaction of two such descending balls. The computational results are quite comparable to those in the literature. As a further example of an application, we include a freely falling maple seed with autorotation.

  20. Lorentz Contraction, Bell's Spaceships and Rigid Body Motion in Special Relativity

    ERIC Educational Resources Information Center

    Franklin, Jerrold

    2010-01-01

    The meaning of Lorentz contraction in special relativity and its connection with Bell's spaceships parable is discussed. The motion of Bell's spaceships is then compared with the accelerated motion of a rigid body. We have tried to write this in a simple form that could be used to correct students' misconceptions due to conflicting earlier…

  1. Rigid body constraints realized in massively-parallel molecular dynamics on graphics processing units

    NASA Astrophysics Data System (ADS)

    Nguyen, Trung Dac; Phillips, Carolyn L.; Anderson, Joshua A.; Glotzer, Sharon C.

    2011-11-01

    Molecular dynamics (MD) methods compute the trajectory of a system of point particles in response to a potential function by numerically integrating Newton's equations of motion. Extending these basic methods with rigid body constraints enables composite particles with complex shapes such as anisotropic nanoparticles, grains, molecules, and rigid proteins to be modeled. Rigid body constraints are added to the GPU-accelerated MD package, HOOMD-blue, version 0.10.0. The software can now simulate systems of particles, rigid bodies, or mixed systems in microcanonical (NVE), canonical (NVT), and isothermal-isobaric (NPT) ensembles. It can also apply the FIRE energy minimization technique to these systems. In this paper, we detail the massively parallel scheme that implements these algorithms and discuss how our design is tuned for the maximum possible performance. Two different case studies are included to demonstrate the performance attained, patchy spheres and tethered nanorods. In typical cases, HOOMD-blue on a single GTX 480 executes 2.5-3.6 times faster than LAMMPS executing the same simulation on any number of CPU cores in parallel. Simulations with rigid bodies may now be run with larger systems and for longer time scales on a single workstation than was previously even possible on large clusters.

  2. Aquatic turning performance of painted turtles (Chrysemys picta) and functional consequences of a rigid body design.

    PubMed

    Rivera, Gabriel; Rivera, Angela R V; Dougherty, Erin E; Blob, Richard W

    2006-11-01

    The ability to capture prey and avoid predation in aquatic habitats depends strongly on the ability to perform unsteady maneuvers (e.g. turns), which itself depends strongly on body flexibility. Two previous studies of turning performance in rigid-bodied taxa have found either high maneuverability or high agility, but not both. However, examinations of aquatic turning performance in rigid-bodied animals have had limited taxonomic scope and, as such, the effects of many body shapes and designs on aquatic maneuverability and agility have yet to be examined. Turtles represent the oldest extant lineage of rigid-bodied vertebrates and the only aquatic rigid-bodied tetrapods. We evaluated the aquatic turning performance of painted turtles, Chrysemys picta (Schneider, 1783) using the minimum length-specific radius of the turning path (R/L) and the average turning rate (omega(avg)) as measures of maneuverability and agility, respectively. We filmed turtles conducting forward and backward turns in an aquatic arena. Each type of turn was executed using a different pattern of limb movements. During forward turns, turtles consistently protracted the inboard forelimb and held it stationary into the flow, while continuing to move the outboard forelimb and both hindlimbs as in rectilinear swimming. The limb movements of backward turns were more complex than those of forward turns, but involved near simultaneous retraction and protraction of contralateral fore- and hindlimbs, respectively. Forward turns had a minimum R/L of 0.0018 (the second single lowest value reported from any animal) and a maximum omega(avg) of 247.1 degrees. Values of R/L for backward turns (0.0091-0.0950 L) were much less variable than that of forward turns (0.0018-1.0442 L). The maneuverability of turtles is similar to that recorded previously for rigid-bodied boxfish. However, several morphological features of turtles (e.g. shell morphology and limb position) appear to increase agility relative to the body

  3. Almost global finite-time stabilization of rigid body attitude motion

    NASA Astrophysics Data System (ADS)

    Bohn, Jan

    This dissertation considers continuous finite-time stabilization of rigid body attitude dynamics using a coordinate-free representation of attitude on the Lie group of rigid body rotations in three dimensions, SO(3). First a general methodology to construct control Lyapunov functions that are Holder continuous and that can be used to show finite-time stability of the feedback controlled system, is presented. The dynamics is represented by generalized (local) coordinates. This methodology is then extended, using a Holder continuous Morse-Lyapunov function, to obtain a finite-time feedback stabilization scheme for rigid body attitude motion to a desired attitude with continuous state feedback. The feedback control law designed here leads to almost global finite-time stabilization of the attitude motion of a rigid body with Holder continuous feedback, to the desired attitude. Furthermore, using the finite-time feedback stabilization scheme, a state observer is proposed for rigid body attitude motion with a given attitude dynamics model that in the absence of measurement noise and disturbance torques leads to almost global finite-time stable convergence of attitude motion state estimates to the actual states for a rigid body whose inertia is known. Subsequently this state observer is combined with a deterministic filter scheme that utilizes a set of sigma points obtained from the unscented transform based on exponential coordinates. This estimation scheme uses discrete-time state measurements of inertially known vectors along with rate gyro measurements of the angular velocity, to obtain state estimates in the filtering stage. Additionally, a set of sigma points is obtained from the unscented transform, with re-sampling centered at the current state estimate at each measurement instant. The state estimates along with sampled sigma points are propagated between measurement instants, using the discrete-time attitude state observer that is almost globally finite

  4. Mutual potential between two rigid bodies with arbitrary shapes and mass distributions

    NASA Astrophysics Data System (ADS)

    Hou, Xiyun; Scheeres, Daniel J.; Xin, Xiaosheng

    2016-09-01

    Formulae to compute the mutual potential, force, and torque between two rigid bodies are given. These formulae are expressed in Cartesian coordinates using inertia integrals. They are valid for rigid bodies with arbitrary shapes and mass distributions. By using recursive relations, these formulae can be easily implemented on computers. Comparisons with previous studies show their superiority in computation speed. Using the algorithm as a tool, the planar problem of two ellipsoids is studied. Generally, potential truncated at the second order is good enough for a qualitative description of the mutual dynamics. However, for ellipsoids with very large non-spherical terms, higher order terms of the potential should be considered, at the cost of a higher computational cost. Explicit formulae of the potential truncated to the fourth order are given.

  5. Mutual potential between two rigid bodies with arbitrary shapes and mass distributions

    NASA Astrophysics Data System (ADS)

    Hou, Xiyun; Scheeres, Daniel J.; Xin, Xiaosheng

    2017-03-01

    Formulae to compute the mutual potential, force, and torque between two rigid bodies are given. These formulae are expressed in Cartesian coordinates using inertia integrals. They are valid for rigid bodies with arbitrary shapes and mass distributions. By using recursive relations, these formulae can be easily implemented on computers. Comparisons with previous studies show their superiority in computation speed. Using the algorithm as a tool, the planar problem of two ellipsoids is studied. Generally, potential truncated at the second order is good enough for a qualitative description of the mutual dynamics. However, for ellipsoids with very large non-spherical terms, higher order terms of the potential should be considered, at the cost of a higher computational cost. Explicit formulae of the potential truncated to the fourth order are given.

  6. Topological classification of the Goryachev integrable case in rigid body dynamics

    NASA Astrophysics Data System (ADS)

    Nikolaenko, S. S.

    2016-01-01

    A topological analysis of the Goryachev integrable case in rigid body dynamics is made on the basis of the Fomenko-Zieschang theory. The invariants (marked molecules) which are obtained give a complete description, from the standpoint of Liouville classification, of the systems of Goryachev type on various level sets of the energy. It turns out that on appropriate energy levels the Goryachev case is Liouville equivalent to many classical integrable systems and, in particular, the Joukowski, Clebsch, Sokolov and Kovalevskaya-Yehia cases in rigid body dynamics, as well as to some integrable billiards in plane domains bounded by confocal quadrics -- in other words, the foliations given by the closures of generic solutions of these systems have the same structure. Bibliography: 15 titles.

  7. Compliant mechanism road bicycle brake: a rigid-body replacement case study

    SciTech Connect

    Olsen, Brian M; Howell, Larry L; Magleby, Spencer P

    2011-01-19

    The design of high-performance bicycle brakes is complicated by the competing design objectives of increased performance and low weight. But this challenge also provides a good case study to demonstrate the design of compliant mechanisms to replace current rigid-link mechanisms. This paper briefly reviews current road brake designs, demonstrates the use of rigid-body replacement synthesis to design a compliant mechanism, and illustrates the combination of compliant mechanism design tools. The resulting concept was generated from the modified dual-pivot brake design and is a partially compliant mechanism where one pin has the dual role of a joint and a mounting pin. The pseudo-rigid-body model, finite element analysis, and optimization algorithms are used to generate design dimensions, and designs are considered for both titanium and E-glass flexures. The resulting design has the potential of reducing the part count and overall weight while maintaining a performance similar to the benchmark.

  8. Planar dynamics of a uniform beam with rigid bodies affixed to the ends

    NASA Technical Reports Server (NTRS)

    Storch, J.; Gates, S.

    1983-01-01

    The planar dynamics of a uniform elastic beam subject to a variety of geometric and natural boundary conditions and external excitations were analyzed. The beams are inextensible and capable of small transverse bending deformations only. Classical beam vibration eigenvalue problems for a cantilever with tip mass, a cantilever with tip body and an unconstrained beam with rigid bodies at each are examined. The characteristic equations, eigenfunctions and orthogonality relations for each are derived. The forced vibration of a cantilever with tip body subject to base acceleration is analyzed. The exact solution of the governing nonhomogeneous partial differential equation with time dependent boundary conditions is presented and compared with a Rayleigh-Ritz approximate solution. The arbitrary planar motion of an elastic beam with rigid bodies at the ends is addressed. Equations of motion are derived for two modal expansions of the beam deflection. The motion equations are cast in a first order form suitable for numerical integration. Selected FORTRAN programs are provided.

  9. Rigid Body Stability Augmentation Studies for a Wind Tunnel Flutter Model.

    DTIC Science & Technology

    1985-11-01

    evident in the root locus diagrams, Figs 3 and 4. Therefore, the stability augmentation system (SAS) was required to - provide basic stability and if... augmentation system (SAS) control law for it. The RAE designed control system simulation and analysis computer package ’TSIM’ (Refs. 3, 4) was used to program...One of my activities in preparation for the Phase 2 trials was to investigate the rigid-body response of the model and to develop a stability

  10. The phase topology of a special case of Goryachev integrability in rigid body dynamics

    SciTech Connect

    Ryabov, P. E.

    2014-07-31

    The phase topology of a special case of Goryachev integrability in the problem of motion of a rigid body in a fluid is investigated using the method of Boolean functions, which was developed by Kharlamov for algebraically separated systems. The bifurcation diagram of the moment map is found and the Fomenko invariant, which classifies the systems up to rough Liouville equivalence, is specified. Bibliography: 15 titles. (paper)

  11. Hamilton's Equations with Euler Parameters for Rigid Body Dynamics Modeling. Chapter 3

    NASA Technical Reports Server (NTRS)

    Shivarama, Ravishankar; Fahrenthold, Eric P.

    2004-01-01

    A combination of Euler parameter kinematics and Hamiltonian mechanics provides a rigid body dynamics model well suited for use in strongly nonlinear problems involving arbitrarily large rotations. The model is unconstrained, free of singularities, includes a general potential energy function and a minimum set of momentum variables, and takes an explicit state space form convenient for numerical implementation. The general formulation may be specialized to address particular applications, as illustrated in several three dimensional example problems.

  12. Evaluation of Rigid-Body Motion Compensation in Cardiac Perfusion SPECT Employing Polar-Map Quantification.

    PubMed

    Pretorius, P Hendrik; Johnson, Karen L; King, Michael A

    2016-06-01

    We have recently been successful in the development and testing of rigid-body motion tracking, estimation and compensation for cardiac perfusion SPECT based on a visual tracking system (VTS). The goal of this study was to evaluate in patients the effectiveness of our rigid-body motion compensation strategy. Sixty-four patient volunteers were asked to remain motionless or execute some predefined body motion during an additional second stress perfusion acquisition. Acquisitions were performed using the standard clinical protocol with 64 projections acquired through 180 degrees. All data were reconstructed with an ordered-subsets expectation-maximization (OSEM) algorithm using 4 projections per subset and 5 iterations. All physical degradation factors were addressed (attenuation, scatter, and distance dependent resolution), while a 3-dimensional Gaussian rotator was used during reconstruction to correct for six-degree-of-freedom (6-DOF) rigid-body motion estimated by the VTS. Polar map quantification was employed to evaluate compensation techniques. In 54.7% of the uncorrected second stress studies there was a statistically significant difference in the polar maps, and in 45.3% this made a difference in the interpretation of segmental perfusion. Motion correction reduced the impact of motion such that with it 32.8 % of the polar maps were statistically significantly different, and in 14.1% this difference changed the interpretation of segmental perfusion. The improvement shown in polar map quantitation translated to visually improved uniformity of the SPECT slices.

  13. A new pre-loaded beam geometric stiffness matrix with full rigid body capabilities

    NASA Technical Reports Server (NTRS)

    Bosela, P. A.; Fertis, D. G.; Shaker, F. J.

    1992-01-01

    Space structures, such as the Space Station solar arrays, must be extremely light-weight, flexible structures. Accurate prediction of the natural frequencies and mode shapes is essential for determining the structural adequacy of components, and designing a controls system. The tension pre-load in the 'blanket' of photovoltaic solar collectors, and the free/free boundary conditions of a structure in space, causes serious reservations on the use of standard finite element techniques of solution. In particular, a phenomenon known as 'grounding', or false stiffening, of the stiffness matrix occurs during rigid body rotation. The authors have previously shown that the grounding phenomenon is caused by a lack of rigid body rotational capability, and is typical in beam geometric stiffness matrices formulated by others, including those which contain higher order effects. The cause of the problem was identified as the force imbalance inherent in the formulations. In this paper, the authors develop a beam geometric stiffness matrix for a directed force problem, and show that the resultant global stiffness matrix contains complete rigid body mode capabilities, and performs very well in the diagonalization methodology customarily used in dynamic analysis.

  14. An Interface for Specifying Rigid-Body Motions for CFD Applications

    NASA Technical Reports Server (NTRS)

    Murman, Scott M.; Chan, William; Aftosmis, Michael; Meakin, Robert L.; Kwak, Dochan (Technical Monitor)

    2003-01-01

    An interface for specifying rigid-body motions for CFD applications is presented. This interface provides a means of describing a component hierarchy in a geometric configuration, as well as the motion (prescribed or six-degree-of-freedom) associated with any component. The interface consists of a general set of datatypes, along with rules for their interaction, and is designed to be flexible in order to evolve as future needs dictate. The specification is currently implemented with an XML file format which is portable across platforms and applications. The motion specification is capable of describing general rigid body motions, and eliminates the need to write and compile new code within the application software for each dynamic configuration, allowing client software to automate dynamic simulations. The interface is integrated with a GUI tool which allows rigid body motions to be prescribed and verified interactively, promoting access to non-expert users. Illustrative examples, as well as the raw XML source of the file specifications, are included.

  15. Strongly coupled dynamics of fluids and rigid-body systems with the immersed boundary projection method

    NASA Astrophysics Data System (ADS)

    Wang, Chengjie; Eldredge, Jeff D.

    2015-08-01

    A strong coupling algorithm is presented for simulating the dynamic interactions between incompressible viscous flows and rigid-body systems in both two- and three-dimensional problems. In this work, the Navier-Stokes equations for incompressible flow are solved on a uniform Cartesian grid by the vorticity-based immersed boundary projection method of Colonius and Taira. Dynamical equations for arbitrary rigid-body systems are also developed. The proposed coupling method attempts to unify the treatment of constraints in the fluid and structure-the incompressibility of the fluid, the linkages in the rigid-body system, and the conditions at the interface-through the use of Lagrange multipliers. The resulting partitioned system of equations is solved with a simple relaxation scheme, based on an identification of virtual inertia from the fluid. The scheme achieves convergence in only 2 to 5 iterations per time step for a wide variety of mass ratios. The formulation requires that only a subset of the discrete fluid equations be solved in each iteration. Several two- and three-dimensional numerical tests are conducted to validate and demonstrate the method, including a falling cylinder, flapping of flexible wings, self-excited oscillations of a system of many linked plates in a free stream, and passive pivoting of a finite aspect ratio plate under the influence of gravity in a free stream. The results from the current method are compared with previous experimental and numerical results and good agreement is achieved.

  16. Rigid Body Modes Influence On Microvibration Analysis-Application To Swarm

    NASA Astrophysics Data System (ADS)

    Laduree, G.; Fransen, S.; Baldesi, G.; Pflieger, I.

    2012-07-01

    Microvibrations are defined as low level mechanical disturbances affecting payload performance, generated by mobile parts or mechanism operating on-board the spacecraft, like momentum or reaction wheels, pointing mechanism, cryo-coolers or thrusters. The disturbances caused by these sources are transmitted through the spacecraft structure and excite modes of that structure or elements of the payload impacting its performance (e.g. Line of sight rotations inducing some image quality degradation). The dynamic interaction between these three elements (noise source, spacecraft structure and sensitive receiver) makes the microvibration prediction a delicate problem. Microvibration sources are generally of concern in the frequency range from a few Hz to 1000 Hz. However, in some specific cases, high stability at lower frequencies might be requested. This is the case of the SWARM mission, whose objectives are to provide the best ever survey of the geomagnetic field and its temporal evolution as well as supplementary information for studying the interaction of the magnetic field with other physical quantities describing the Earth system (e.g. ocean circulation). Among its instruments, SWARM is embarking a very sensitive 6-axis accelerometer in the low frequency range (10-8 m/s2 or rad/s2 between 10-4 and 0.1 Hz) located at its Centre of Gravity and an Absolute Scalar Magnetometer located at the tip of a boom far from the spacecraft body. The ASM performs its measurements by rotating an alternative magnetic field around its main axis thanks to a piezo-electric motor. This repeated disturbance might generate some pollution of the accelerometer science data. The objective of this work is to focus on the interaction of the rigid body mode calculation method with the elastic contribution of the normal modes excited by the noise source frequency content. It has indeed been reported in the past that NASTRAN Lanczos rigid body modes may lead to inaccurate rigid-body accelerations

  17. Dynamic analysis of a system of hinge-connected rigid bodies with nonrigid appendages. [equations of motion

    NASA Technical Reports Server (NTRS)

    Likins, P. W.

    1974-01-01

    Equations of motion are derived for use in simulating a spacecraft or other complex electromechanical system amenable to idealization as a set of hinge-connected rigid bodies of tree topology, with rigid axisymmetric rotors and nonrigid appendages attached to each rigid body in the set. In conjunction with a previously published report on finite-element appendage vibration equations, this report provides a complete minimum-dimension formulation suitable for generic programming for digital computer numerical integration.

  18. Characterization of Self-Excited, Nearly Axisymmetric, Spinning Rigid-Body Motion as an Oblate Epicycloid

    NASA Astrophysics Data System (ADS)

    McNair, S. Lauren; Tragesser, Steven

    2017-03-01

    A unique formulation of the solution to a spinning, nearly axisymmetric rigid-body is presented. Direct integration of the linearized equations of motion gives accurate results for nearly axisymmetric inertia ellipsoids while avoiding the complexity of more general formulations. The simplicity of the formulation lends itself to a better understanding of the system behavior. Specifically, the motion of the spin axis for this nearly axisymmetric case is described by an oblate epicycloid, providing an extension of the classic epicycloid solution for axisymmetric objects.

  19. Detection of micromechanical deformation under rigid body displacement using twin-pulsed 3D digital holography

    NASA Astrophysics Data System (ADS)

    Perez-Lopez, Carlos; Hernandez-Montes, Maria del Socorro; Mendoza-Santoyo, Fernando

    2005-02-01

    Twin-pulsed digital holography in its 3D set up is used to recover exclusively the micro-mechanical deformation of an object. The test object is allowed to have rigid body movements such as rotation and translation, with the result that the fringe patterns contain information of the latter and the object deformation, a feature that may significantly modify the interpretation of the results. Experimental results from a flat metal plate subject to micro stress and a displacement in the x-z plane are presented to demonstrate that using this optical method it is possible to recover exclusively the contribution of the micro stress.

  20. An implicit time-stepping scheme for rigid body dynamics with Coulomb friction

    SciTech Connect

    STEWART,DAVID; TRINKLE,JEFFREY C.

    2000-02-15

    In this paper a new time-stepping method for simulating systems of rigid bodies is given. Unlike methods which take an instantaneous point of view, the method is based on impulse-momentum equations, and so does not need to explicitly resolve impulsive forces. On the other hand, the method is distinct from previous impulsive methods in that it does not require explicit collision checking and it can handle simultaneous impacts. Numerical results are given for one planar and one three-dimensional example, which demonstrate the practicality of the method, and its convergence as the step size becomes small.

  1. Analytic Theory and Control of the Motion of Spinning Rigid Bodies

    NASA Technical Reports Server (NTRS)

    Tsiotras, Panagiotis

    1993-01-01

    Numerical simulations are often resorted to, in order to understand the attitude response and control characteristics of a rigid body. However, this approach in performing sensitivity and/or error analyses may be prohibitively expensive and time consuming, especially when a large number of problem parameters are involved. Thus, there is an important role for analytical models in obtaining an understanding of the complex dynamical behavior. In this dissertation, new analytic solutions are derived for the complete attitude motion of spinning rigid bodies, under minimal assumptions. Hence, we obtain the most general solutions reported in the literature so far. Specifically, large external torques and large asymmetries are included in the problem statement. Moreover, problems involving large angular excursions are treated in detail. A new tractable formulation of the kinematics is introduced which proves to be extremely helpful in the search for analytic solutions of the attitude history of such kinds of problems. The main utility of the new formulation becomes apparent however, when searching for feedback control laws for stabilization and/or reorientation of spinning spacecraft. This is an inherently nonlinear problem, where standard linear control techniques fail. We derive a class of control laws for spin axis stabilization of symmetric spacecraft using only two pairs of gas jet actuators. Practically, this could correspond to a spacecraft operating in failure mode, for example. Theoretically, it is also an important control problem which, because of its difficulty, has received little, if any, attention in the literature. The proposed control laws are especially simple and elegant. A feedback control law that achieves arbitrary reorientation of the spacecraft is also derived, using ideas from invariant manifold theory. The significance of this research is twofold. First, it provides a deeper understanding of the fundamental behavior of rigid bodies subject to body

  2. Annihilation of angular momentum drift during spinning-up and thrusting maneuvers of rigid bodies

    NASA Technical Reports Server (NTRS)

    Longuski, J. M.; Kia, T.; Breckenridge, W. G.

    1984-01-01

    A very simple, yet accurate, heuristic solution for the spiral path of the angular momentum vector during spin-up and spin-down maneuvers of rigid body spacecraft is presented. A two-burn scheme is proposed consisting of a burn, a coast, and a second burn of the spin thruster. The appropriate burn times are found by a transcendental equation similar to Kepler's equation. Numerical results verify the accuracy of the burn, coast, and burn times given by closed form expressions. The scheme can also be applied to the problem of axial thrusting during constant spin.

  3. Fast time-reversible algorithms for molecular dynamics of rigid-body systems

    NASA Astrophysics Data System (ADS)

    Kajima, Yasuhiro; Hiyama, Miyabi; Ogata, Shuji; Kobayashi, Ryo; Tamura, Tomoyuki

    2012-06-01

    In this paper, we present time-reversible simulation algorithms for rigid bodies in the quaternion representation. By advancing a time-reversible algorithm [Y. Kajima, M. Hiyama, S. Ogata, and T. Tamura, J. Phys. Soc. Jpn. 80, 114002 (2011), 10.1143/JPSJ.80.114002] that requires iterations in calculating the angular velocity at each time step, we propose two kinds of iteration-free fast time-reversible algorithms. They are easily implemented in codes. The codes are compared with that of existing algorithms through demonstrative simulation of a nanometer-sized water droplet to find their stability of the total energy and computation speeds.

  4. On the photogravitational R4BP when the third primary is a triaxial rigid body

    NASA Astrophysics Data System (ADS)

    Asique, Md Chand; Prasad, Umakant; Hassan, M. R.; Suraj, Md Sanam

    2016-12-01

    The present paper deals with the photogravitational restricted four-body problem, when the third primary is placed at the triangular libration point of the restricted three-body problem is a triaxial rigid body. The third primary m3 is not influencing the motion of the dominating primaries m1 and m2. We have studied the motion of m4, moving under the influence of the three primaries mi, i=1,2,3, but the motion of the primaries is not being influenced by infinitesimal mass m4. The aim of this study is to find the locations of equilibrium points and discuss their stability. We have obtained six non-collinear equilibrium points near the third body when the third body is a triaxial rigid body and a source of radiation. There exist at most ten non-collinear equilibrium points in total for this problem. However, the number of equilibrium points depends on the triaxiality parameters. Further, we have drawn the zero velocity surfaces to determine the possible allowed boundary regions. The stability of non-collinear equilibrium points for different mass parameters, radiation parameters and triaxiality of the third body is also studied. The stability regions of the equilibrium points were expanded due to the triaxiality of the third body and various values of the radiation parameter q.

  5. Coupled motion of rigid bodies about their center of mass. [Shuttle/payload system

    NASA Technical Reports Server (NTRS)

    Jezewski, D. J.; Donaldson, J. D.

    1979-01-01

    Nontrivial analytical solutions for the coupled motion of two rigid bodies about their center of mass are obtained on the assumptions that the rigid bodies are coupled by a massless rigid boom and that no external forces are acting on the system. Both relative rotational and translational motions of the two bodies are considered. General equations of motion are derived by regarding the two bodies as consisting of two distinct systems of particles and by applying the principle of conservation of angular momentum. It is shown that a basic nontrivial solution can be obtained for the translational problem if an assumption is made concerning the relative orientation of one principal axis of inertia of each body and that fundamental nontrivial solutions are readily obtained for the rotational problem if an additional assumption is made with respect to the symmetry of one body. Certain stability criteria are found for some of these motions by defining regions of constraint for the relative translational and rotational elements.

  6. Rigid body mode identification of the PAH-2 helicopter using the eigensystem realization algorithm

    NASA Technical Reports Server (NTRS)

    Schenk, Axel; Pappa, Richard S.

    1992-01-01

    The rigid body modes of the PAH-2 'Tiger' helicopter were identified using the Eigensystem Realization Algorithm (ERA). This work complements ground vibration tests performed using DLR's traditional phase resonance technique and the ISSPA (Identification of Structural System Parameters) method. Rigid body modal parameters are important for ground resonance prediction. Time-domain data for ERA were obtained by inverse Fourier transformation of frequency response functions measured with stepped-sine excitation. Mode purity (based on the Phase Resonance Criterion) was generally equal to or greater than corresponding results obtained in the ground vibration tests. All identified natural frequencies and mode shapes correlate well with corresponding ground vibration test results. The modal identification approach discussed in this report has become increasingly attractive in recent years due to the steadily declining cost and increased performance of scientific computers. As illustrated in this application, modern time-domain methods can be successfully applied to data acquired using DLR's existing test equipment. Some suggestions are made for future applications of time domain modal identification in this manner.

  7. Rotational kinematics of a rigid body about a fixed axis: development and analysis of an inventory

    NASA Astrophysics Data System (ADS)

    Mashood, K. K.; Singh, Vijay A.

    2015-07-01

    We present the development, administration, and analysis of a focused inventory on the rotational kinematics of a rigid body around a fixed axis. The inventory, which is made up of 13 multiple-choice questions, was developed on the basis of interactions with students and teachers. The systematic and iterative aspects of the construction of the inventory are illustrated. The questions, which were validated, were administered to a set of teachers (N = 25) and two groups of preuniversity students (N = 74 and 905) in India. Students, as well as teachers, exhibited difficulties in applying the operational definition of angular velocity to a rigid body. Many erroneously assumed that an angular acceleration cannot exist without a net torque. Patterns of reasoning resulting in errors were identified and categorized under four broad themes. These include inappropriate extensions of familiar procedural practices, reasoning cued by primitive elements in thought, lack of differentiation between related but distinct concepts, and indiscriminate use of equations. The inventory was also administered to introductory-level students (N = 384) at the University of Washington. Popular distractors to most items were similar to the Indian students.

  8. Classification of the classical SL(2 , R) gauge transformations in the rigid body

    NASA Astrophysics Data System (ADS)

    de la Cruz, Manuel; Gaspar, Néstor; Jiménez-Lara, Lidia; Linares, Román

    2017-04-01

    In this paper we revisit the classification of the gauge transformations in the Euler top system using the generalized classical Hamiltonian dynamics of Nambu. In this framework the Euler equations of motion are bi-Hamiltonian and SL(2 , R) linear combinations of the two Hamiltonians leave the equations of motion invariant, although belonging to inequivalent Lie-Poisson structures. Here we give the explicit form of the Hamiltonian vector fields associated to the components of the angular momentum for every single Lie-Poisson structure including both the asymmetric rigid bodies and its symmetric limits. We also give a detailed classification of the different Lie-Poisson structures recovering all the ones reported previously in the literature.

  9. Simulation of vortex-induced vibrations of a cylinder using ANSYS CFX rigid body solver

    NASA Astrophysics Data System (ADS)

    Izhar, Abubakar; Qureshi, Arshad Hussain; Khushnood, Shahab

    2017-03-01

    This article simulates the vortex-induced oscillations of a rigid circular cylinder with elastic support using the new ANSYS CFX rigid body solver. This solver requires no solid mesh to setup FSI (Fluid Structure Interaction) simulation. The two-way case was setup in CFX only. Specific mass of the cylinder and flow conditions were similar to previous experimental data with mass damping parameter equal to 0.04, specific mass of 1 and Reynolds number of 3800. Two dimensional simulations were setup. Both one-degree-of-freedom and two-degree-of-freedom cases were run and results were obtained for both cases with reasonable accuracy as compared with experimental results. Eight-figure XY trajectory and lock-in behavior were clearly captured. The obtained results were satisfactory.

  10. Unsteady transonic flow past airfoils in rigid-body motion. [UFLO5

    SciTech Connect

    Chang, I C

    1981-03-01

    With the aim of developing a fast and accurate computer code for predicting the aerodynamic forces needed for a flutter analysis, some basic concepts in computational transonics are reviewed. The unsteady transonic flow past airfoils in rigid body motion is adequately described by the potential flow equation as long as the boundary layer remains attached. The two dimensional unsteady transonic potential flow equation in quasilinear form with first order radiation boundary conditions is solved by an alternating direction implicit scheme in an airfoil attached sheared parabolic coordinate system. Numerical experiments show that the scheme is very stable and is able to resolve the higher nonlinear transonic effects for filter analysis within the context of an inviscid theory.

  11. Active control of elastic and rigid body response of a three-dimensional underwater structure

    SciTech Connect

    Suzuki, H.; Yoshida, K.; Watanabe, K.

    1995-02-01

    One key technology for the offshore development of the increasing water depth will be remotely operated installation and construction of flexible structure in the deep water or on the seabed. The flexibility comes from scale-up or weight reduction of the structure. Conventional operation from the sea surfaces is affected by the weather conditions, and, therefore, not so efficient. This paper presents basic research on active control of elastic response and rigid body motion of an underwater elastic structure toward the remotely operated installation technique. The numerical model of the dynamics of the structural model is formulated, and based on the numerical model the control is formulated. The formulated control is tested by computer simulations and model experiments. The structural model is propelled by thrusters and taken from initial position to another position, while the elastic responses are controlled by variable buoyancy-type actuators.

  12. Identification of motion parameters of a rigid body from its orthogonal and perspective projections

    NASA Technical Reports Server (NTRS)

    Ganguly, S.; Ghosh, B.; Tarn, T. J.; Bejczy, A. K.

    1989-01-01

    An estimate is made of the motion parameters, namely, linear and angular velocities, of a rigid body rotating and translating in three-space. The authors assume that the velocities are constant and that the motion is not completely observable. They consider two separate cases of partial observations corresponding to the orthogonal and the perspective projections, respectively. If (x, y, z) is the Cartesian coordinate of the three-space, the authors assume in the first case that the projection of the motion on the x-y plane is observed. If (r, theta, phi) is the polar coordinates of the three-space, they assume in the second case that the parameter vector (theta, phi) is observed. The use of both of these cases to estimate the motion parameters is discussed.

  13. On the problem of free deceleration of a rigid body in a resisting medium

    NASA Astrophysics Data System (ADS)

    Shamolin, M. V.

    2016-07-01

    A mathematical model of the influence of a medium on a rigid body with some part of its external surface being flat is considered with due allowance for an additional dependence of the moment of the medium action force on the angular velocity of the body. A full system of equations of motion is given under quasi-steady conditions; the dynamic part of this system forms an independent third-order system, and an independent second-order subsystem is split from the full system. A new family of phase portraits on a phase cylinder of quasi-velocities is obtained. It is demonstrated that the results obtained allow one to design hollow circular cylinders ("shell cases"), which can ensure necessary stability in conducting additional full-scale experiments.

  14. Implementation of Kane's Method for a Spacecraft Composed of Multiple Rigid Bodies

    NASA Technical Reports Server (NTRS)

    Stoneking, Eric T.

    2013-01-01

    Equations of motion are derived for a general spacecraft composed of rigid bodies connected via rotary (spherical or gimballed) joints in a tree topology. Several supporting concepts are developed in depth. Basis dyads aid in the transition from basis-free vector equations to component-wise equations. Joint partials allow abstraction of 1-DOF, 2-DOF, 3-DOF gimballed and spherical rotational joints to a common notation. The basic building block consisting of an "inner" body and an "outer" body connected by a joint enables efficient organization of arbitrary tree structures. Kane's equation is recast in a form which facilitates systematic assembly of large systems of equations, and exposes a relationship of Kane's equation to Newton and Euler's equations which is obscured by the usual presentation. The resulting system of dynamic equations is of minimum dimension, and is suitable for numerical solution by computer. Implementation is ·discussed, and illustrative simulation results are presented.

  15. On some approximations of the resultant contact forces and their applications in rigid body dynamics

    NASA Astrophysics Data System (ADS)

    Kudra, Grzegorz; Szewc, Michał; Wojtunik, Igor; Awrejcewicz, Jan

    2016-10-01

    The work presents the possible applications and effectiveness of certain class of models of the resultant friction force and rolling resistance. The friction models are based on the integral model constructed under assumption of fully developed sliding on the plane contact area of general shape and any pressure distribution. Then the integral model of friction force and moment are approximated based on Padé approximants and their generalizations. These models are expected to be computationally effective in numerical simulations of rigid bodies with frictional contacts, such like billiard balls, Thompson top, the wobble stone and many others. In the present work two different examples of application of the developed contact models are presented and tested: a) a billiard ball rolling and sliding on the plane horizontal table; b) a full ellipsoid of revolution in contact with plane and horizontal base.

  16. Recursive dynamics of topological trees of rigid bodies via Kalman filtering and Bryson-Frazier smoothing

    NASA Technical Reports Server (NTRS)

    Rodriguez, G.

    1988-01-01

    The inverse and forward dynamics problems for a set of rigid bodies connected by hinges to form a topological tree are solved by using recursive techniques from linear filtering and smoothing theory. An inward filtering sequence computes a set of constraint moments and forces. This is followed by an outward sequence to determine a corresponding set of angular and linear accelerations. An inward sequence begins at the tips of all of the terminal bodies of the tree and proceeds inwardly through all of the branches until it reaches the root. Similarly, an outward sequence begins at the root and propagates to all of the tree branches until it reaches the tips of the terminal bodies. The paper also provides an approach to evaluate recursively the composite multibody system inertia matrix and its inverse.

  17. The Serret-Andoyer Formalism in Rigid-Body Dynamics: 1. Symmetries and Perturbations

    DTIC Science & Technology

    2007-01-01

    2 + ( 1 I1 − 1 I2 ) ∂S ∂θ ( ∂S ∂φ − ∂S ∂ψ cos θ ) sinψ cosψ sin θ + ∂S ∂t = H∗ ( ∂S ∂ P , P , t ) . (50) At this point, Serret [22], Radau [23], and...Andoyer Formalism in Rigid-Body Dynamics: I. Symmetries and Perturbations P . Gurfil1*, A. Elipe2**, W. Tangren3***, and M. Efroimsky4**** 1Faculty of...g3 = GcJ . (42) 3. THE SERRET–ANDOYER TRANSFORMATION 3.1. Richelot (1850), Serret (1866), Radau (1869), Tisserand (1889) The method presently referred

  18. Distributed event-triggered cooperative attitude control of multiple rigid bodies with leader-follower architecture

    NASA Astrophysics Data System (ADS)

    Weng, Shengxuan; Yue, Dong

    2016-02-01

    In this note, the distributed event-triggered cooperative attitude control of multiple rigid bodies with leader-follower architecture is investigated, where both the cases of static and dynamic leaders are all considered. Two distributed triggering procedures are first introduced for the followers and leaders, and then the distributed cooperative controllers are designed under the proposed triggering schemes. Under the designed controllers with the event-triggered strategies, it is shown that the orientations of followers converge to the convex hull formed by the desired leaders' orientations with zero angular velocities. Moreover, the communication pressure in network is reduced and the energy of each agent is saved. Simulation results show the effectiveness of the proposed method.

  19. Secular solution for delta-V during spin rate change maneuvers of rigid body spacecraft

    NASA Technical Reports Server (NTRS)

    Klumpe, E. W.; Longuski, J. M.

    1984-01-01

    Analytic expressions have been found for Euler's Equations of Motion and for the Eulerian Angles for both symmetric and near symmetric rigid bodies under the influence of arbitrary constant body-fixed torques. These solutions have been used to solve for the secular terms in the translational delta-V equations in inertial space. This secular delta-V solution is of interest in application to spinning spacecraft in that it describes the average direction of the delta-V of the spacecraft during a spin-up maneuver. Numerical integration of the governing differential equations has verified that the secular delta-V solution is valid for large time and is accurate in many physical situations including spin-up maneuvers of the Galileo spacecraft.

  20. Dynamics on strata of trigonal Jacobians and some integrable problems of rigid body motion

    NASA Astrophysics Data System (ADS)

    Braden, H. W.; Enolski, V. Z.; Fedorov, Yu N.

    2013-07-01

    We present an algebraic geometrical and analytical description of the Goryachev case of rigid body motion. It belongs to a family of systems sharing the same properties: although completely integrable, they are not algebraically integrable, their solution is not meromorphic in the complex time and involves dynamics on the strata of the Jacobian varieties of trigonal curves. Although the strata of hyperelliptic Jacobians have already appeared in the literature in the context of some dynamical systems, the Goryachev case is the first example of an integrable system whose solution involves a more general curve. Several new features (and formulae) are encountered in the solution given in terms of sigma-functions of such a curve.

  1. The dynamics of a rigid body in potential flow with circulation

    NASA Astrophysics Data System (ADS)

    Vankerschaver, J.; Kanso, E.; Marsden, J. E.

    2010-10-01

    We consider the motion of a two-dimensional body of arbitrary shape in a planar irrotational, incompressible fluid with a given amount of circulation around the body. We derive the equations of motion for this system by performing symplectic reduction with respect to the group of volume-preserving diffeomorphisms and obtain the relevant Poisson structures after a further Poisson reduction with respect to the group of translations and rotations. In this way, we recover the equations of motion given for this system by Chaplygin and Lamb, and we give a geometric interpretation for the Kutta-Zhukowski force as a curvature-related effect. In addition, we show that the motion of a rigid body with circulation can be understood as a geodesic flow on a central extension of the special Euclidian group SE(2), and we relate the cocycle in the description of this central extension to a certain curvature tensor.

  2. Output feedback control for rigid-body attitude with constant disturbances

    NASA Astrophysics Data System (ADS)

    Hu, Jinchang; Zhang, Honghua

    2015-03-01

    In this article, the control problem of rigid-body attitude under constant disturbances without angular-velocity measurement is solved by the combination of the immersion and invariance methodology and the dynamic scaling technique. Two observers, which are respectively for estimating the angular velocity and the disturbance, are constructed by utilising the immersion and invariance method. The mismatched term arising from the observers is dominated by the high-gain injection. The control law is a simple proportional-derivative controller plus a disturbance compensation term, where the estimates of the angular velocity and the disturbance from observers are used for feedback directly. The overall closed-loop system is shown to be almost globally asymptotically stable under easy choices of some control parameters. Finally, simulations are conducted to demonstrate the effectiveness of the proposed control scheme.

  3. The problem of exact interior solutions for rotating rigid bodies in general relativity

    NASA Technical Reports Server (NTRS)

    Wahlquist, H. D.

    1993-01-01

    The (3 + 1) dyadic formalism for timelike congruences is applied to derive interior solutions for stationary, axisymmetric, rigidly rotating bodies. In this approach the mathematics is formulated in terms of three-space-covariant, first-order, vector-dyadic, differential equations for a and Omega, the acceleration and angular velocity three-vectors of the rigid body; for T, the stress dyadic of the matter; and for A and B, the 'electric' and 'magnetic' Weyl curvature dyadics which describe the gravitational field. It is shown how an appropriate ansatz for the forms of these dyadics can be used to discover exact rotating interior solutions such as the perfect fluid solution first published in 1968. By incorporating anisotropic stresses, a generalization is found of that previous solution and, in addition, a very simple new solution that can only exist in toroidal configurations.

  4. The generalized Euler-Poinsot rigid body equations: explicit elliptic solutions

    NASA Astrophysics Data System (ADS)

    Fedorov, Yuri N.; Maciejewski, Andrzej J.; Przybylska, Maria

    2013-10-01

    The classical Euler-Poinsot case of the rigid body dynamics admits a class of simple but non-trivial integrable generalizations, which modify the Poisson equations describing the motion of the body in space. These generalizations possess first integrals which are polynomial in the angular momenta. We consider the modified Poisson equations as a system of linear equations with elliptic coefficients and show that all the solutions of it are single-valued. By using the vector generalization of the Picard theorem, we derive the solutions explicitly in terms of sigma-functions of the corresponding elliptic curve. The solutions are accompanied by a numerical example. We also compare the generalized Poisson equations with the classical third order Halphen equation.

  5. Attitude dynamics simulation subroutines for systems of hinge-connected rigid bodies

    NASA Technical Reports Server (NTRS)

    Fleischer, G. E.; Likins, P. W.

    1974-01-01

    Several computer subroutines are designed to provide the solution to minimum-dimension sets of discrete-coordinate equations of motion for systems consisting of an arbitrary number of hinge-connected rigid bodies assembled in a tree topology. In particular, these routines may be applied to: (1) the case of completely unrestricted hinge rotations, (2) the totally linearized case (all system rotations are small), and (3) the mixed, or partially linearized, case. The use of the programs in each case is demonstrated using a five-body spacecraft and attitude control system configuration. The ability of the subroutines to accommodate prescribed motions of system bodies is also demonstrated. Complete listings and user instructions are included for these routines (written in FORTRAN V) which are intended as multi- and general-purpose tools in the simulation of spacecraft and other complex electromechanical systems.

  6. On the geometry of motions in one integrable problem of the rigid body dynamics

    NASA Astrophysics Data System (ADS)

    Kharlamova, I. I.; Savushkin, A. Y.

    2015-01-01

    Due to Poinsot's theorem, the motion of a rigid body about a fixed point is represented as rolling without slipping of the moving hodograph of the angular velocity over the fixed one. If the moving hodograph is a closed curve, visualization of motion is obtained by the method of P.V. Kharlamov. For an arbitrary motion in an integrable problem with an axially symmetric force field the moving hodograph densely fills some two-dimensional surface and the fixed one fills a three-dimensional surface. In this paper, we consider the irreducible integrable case in which both hodographs are two-frequency curves. We obtain the equations of bearing surfaces, illustrate the main types of these surfaces. We propose a method of the so-called non-straight geometric interpretation representing the motion of a body as a superposition of two periodic motions.

  7. In Silico Single-Molecule Manipulation of DNA with Rigid Body Dynamics

    PubMed Central

    Carrivain, Pascal; Barbi, Maria; Victor, Jean-Marc

    2014-01-01

    We develop a new powerful method to reproduce in silico single-molecule manipulation experiments. We demonstrate that flexible polymers such as DNA can be simulated using rigid body dynamics thanks to an original implementation of Langevin dynamics in an open source library called Open Dynamics Engine. We moreover implement a global thermostat which accelerates the simulation sampling by two orders of magnitude. We reproduce force-extension as well as rotation-extension curves of reference experimental studies. Finally, we extend the model to simulations where the control parameter is no longer the torsional strain but instead the torque, and predict the expected behavior for this case which is particularly challenging theoretically and experimentally. PMID:24586127

  8. Free Energy Landscapes of Alanine Oligopeptides in Rigid-Body and Hybrid Water Models.

    PubMed

    Nayar, Divya; Chakravarty, Charusita

    2015-08-27

    Replica exchange molecular dynamics is used to study the effect of different rigid-body (mTIP3P, TIP4P, SPC/E) and hybrid (H1.56, H3.00) water models on the conformational free energy landscape of the alanine oligopeptides (acAnme and acA5nme), in conjunction with the CHARMM22 force field. The free energy landscape is mapped out as a function of the Ramachandran angles. In addition, various secondary structure metrics, solvation shell properties, and the number of peptide-solvent hydrogen bonds are monitored. Alanine dipeptide is found to have similar free energy landscapes in different solvent models, an insensitivity which may be due to the absence of possibilities for forming i-(i + 4) or i-(i + 3) intrapeptide hydrogen bonds. The pentapeptide, acA5nme, where there are three intrapeptide backbone hydrogen bonds, shows a conformational free energy landscape with a much greater degree of sensitivity to the choice of solvent model, though the three rigid-body water models differ only quantitatively. The pentapeptide prefers nonhelical, non-native PPII and β-sheet populations as the solvent is changed from SPC/E to the less tetrahedral liquid (H1.56) to an LJ-like liquid (H3.00). The pentapeptide conformational order metrics indicate a preference for open, solvent-exposed, non-native structures in hybrid solvent models at all temperatures of study. The possible correlations between the properties of solvent models and secondary structure preferences of alanine oligopeptides are discussed, and the competition between intrapeptide, peptide-solvent, and solvent-solvent hydrogen bonding is shown to be crucial in the relative free energies of different conformers.

  9. Convergence of a Time-Stepping Scheme for Rigid-Body Dynamics and Resolution of Painlevé's Problem

    NASA Astrophysics Data System (ADS)

    Stewart, David E.

    This paper gives convergence theory for a new implicit time-stepping scheme for general rigid-body dynamics with Coulomb friction and purely inelastic collisions and shocks. An important consequence of this work is the proof of existence of solutions of rigid-body problems which include the famous counterexamples of Painlevé. The mathematical basis for this work is the formulation of the rigid-body problem in terms of measure differential inclusions of Moreau and Monteiro Marques. The implicit time-stepping method is based on complementarity problems, and is essentially a particular case of the algorithm described in Anitescu & Potra [2], which in turn is based on the formulation in Stewart & Trinkle [47].

  10. Molecular dynamics simulations and rigid body (TLS) analysis of aspartate carbamoyltransferase: evidence for an uncoupled R state.

    PubMed Central

    Tanner, J. J.; Smith, P. E.; Krause, K. L.

    1993-01-01

    In the R form of ATCase complexed with the bisubstrate analogue, N-(phosphonacetyl)-L-aspartate, large temperature factors are reported for the allosteric domains of the regulatory chains. We studied the conformational flexibility of the holoenzyme with molecular dynamics simulations and rigid body (TLS) analysis. The results of the molecular dynamics simulations suggest that, although local atomic fluctuations account for the temperature factors of the catalytic and zinc domains, they do not account for the large temperature factors of the allosteric regions. However, the temperature factors of the allosteric domains can be satisfactorily analyzed using a rigid body model. The simulations and rigid body analysis support the idea that the allosteric regions are mechanically uncoupled from the rest of the enzyme in the PALA structure. Implications of this uncoupling for allosteric regulation are discussed. PMID:8318897

  11. Error analysis of analytic solutions for self-excited near-symmetric rigid bodies - A numerical study

    NASA Technical Reports Server (NTRS)

    Kia, T.; Longuski, J. M.

    1984-01-01

    Analytic error bounds are presented for the solutions of approximate models for self-excited near-symmetric rigid bodies. The error bounds are developed for analytic solutions to Euler's equations of motion. The results are applied to obtain a simplified analytic solution for Eulerian rates and angles. The results of a sample application of the range and error bound expressions for the case of the Galileo spacecraft experiencing transverse torques demonstrate the use of the bounds in analyses of rigid body spin change maneuvers.

  12. A few remarks about integrability of the equations of motion of a rigid body in ideal fluid

    NASA Astrophysics Data System (ADS)

    Perelomov, A. M.

    1980-11-01

    We demonstrate that the problem of motion of a rigid body in an ideal fluid for a nondegenerate case is completely integrable by means of the quadratic constants of motion for the Clebsch and Steklov cases only. We construct a Lax pair for a high-dimensional generalization of the Clebsch case.

  13. Calculation of rigid-body conformational changes using restraint-driven Cartesian transformations.

    PubMed Central

    Sompornpisut, P; Liu, Y S; Perozo, E

    2001-01-01

    We present an approach for calculating conformational changes in membrane proteins using limited distance information. The method, named restraint-driven Cartesian transformations, involves 1) the use of relative distance changes; 2) the systematic sampling of rigid body movements in Cartesian space; 3) a penalty evaluation; and 4) model refinement using energy minimization. As a test case, we have analyzed the structural basis of activation gating in the Streptomyces lividans potassium channel (KcsA). A total of 10 pairs of distance restraints derived from site-directed spin labeling and electron paramagnetic resonance (SDSL-EPR) spectra were used to calculate the open conformation of the second transmembrane domains of KcsA (TM2). The SDSL-EPR based structure reveals a gating mechanism consistent with a scissoring-type motion of the TM2 segments that includes a pivot point near middle of the helix. The present approach considerably reduces the amount of time and effort required to establish the overall nature of conformational changes in membrane proteins. It is expected that this approach can be implemented into restrained molecular dynamics protocol to calculate the structure and conformational changes in a variety of membrane protein systems. PMID:11606268

  14. A molecular viewer for the analysis of TLS rigid-body motion in macromolecules.

    PubMed

    Painter, Jay; Merritt, Ethan A

    2005-04-01

    TLS (translation/libration/screw) models describe rigid-body vibrational motions of arbitrary objects. A single-group TLS model can be used to approximate the vibration of an entire protein molecule within a crystal lattice. More complex TLS models are broadly applicable to describing inter-domain and other internal vibrational modes of proteins. Such models can be derived and refined from crystallographic data, but they can also be used to describe the vibrational modes observed through other physical techniques or derived from molecular dynamics. The use of TLS models for protein motion has been relatively limited, partly because the physical meaning of the refined TLS parameters is not intuitive. Here, a molecular viewer, TLSView, is introduced using OpenGL and based on the mmLib library for describing and manipulating macromolecular structural models. This visualization tool allows an intuitive understanding of the physical significance of TLS models derived from crystallographic or other data and may be used as an interactive tool to display and interpret inter-domain or other motions in protein structural models. TLSView may also be used to prepare, analyze and validate TLS models for crystallographic refinement.

  15. Inertial Motions of a Rigid Body with a Cavity Filled with a Viscous Liquid

    NASA Astrophysics Data System (ADS)

    Disser, Karoline; Galdi, Giovanni P.; Mazzone, Giusy; Zunino, Paolo

    2016-07-01

    We study inertial motions of the coupled system, {S}, constituted by a rigid body containing a cavity entirely filled with a viscous liquid. We show that for arbitrary initial data having only finite kinetic energy, every corresponding weak solution (à la Leray-Hopf) converges, as time goes to infinity, to a uniform rotation, unless two central moments of inertia of {S} coincide and are strictly greater than the third one. This corroborates a famous "conjecture" of N.Ye. Zhukovskii in several physically relevant cases. Moreover, we show that, in a known range of initial data, this rotation may only occur along the central axis of inertia of {S} with the larger moment of inertia. We also provide necessary and sufficient conditions for the rigorous nonlinear stability of permanent rotations, which improve and/or generalize results previously given by other authors under different types of approximation. Finally, we present results obtained by a targeted numerical simulation that, on the one hand, complement the analytical findings, whereas, on the other hand, point out new features that the analysis is yet not able to catch, and, as such, lay the foundation for interesting and challenging future investigation.

  16. A simple molecular mechanics integrator in mixed rigid body and dihedral angle space.

    PubMed

    Vitalis, Andreas; Pappu, Rohit V

    2014-07-21

    We propose a numerical scheme to integrate equations of motion in a mixed space of rigid-body and dihedral angle coordinates. The focus of the presentation is biomolecular systems and the framework is applicable to polymers with tree-like topology. By approximating the effective mass matrix as diagonal and lumping all bias torques into the time dependencies of the diagonal elements, we take advantage of the formal decoupling of individual equations of motion. We impose energy conservation independently for every degree of freedom and this is used to derive a numerical integration scheme. The cost of all auxiliary operations is linear in the number of atoms. By coupling the scheme to one of two popular thermostats, we extend the method to sample constant temperature ensembles. We demonstrate that the integrator of choice yields satisfactory stability and is free of mass-metric tensor artifacts, which is expected by construction of the algorithm. Two fundamentally different systems, viz., liquid water and an α-helical peptide in a continuum solvent are used to establish the applicability of our method to a wide range of problems. The resultant constant temperature ensembles are shown to be thermodynamically accurate. The latter relies on detailed, quantitative comparisons to data from reference sampling schemes operating on exactly the same sets of degrees of freedom.

  17. Generalized Predictive Control of Dynamic Systems with Rigid-Body Modes

    NASA Technical Reports Server (NTRS)

    Kvaternik, Raymond G.

    2013-01-01

    Numerical simulations to assess the effectiveness of Generalized Predictive Control (GPC) for active control of dynamic systems having rigid-body modes are presented. GPC is a linear, time-invariant, multi-input/multi-output predictive control method that uses an ARX model to characterize the system and to design the controller. Although the method can accommodate both embedded (implicit) and explicit feedforward paths for incorporation of disturbance effects, only the case of embedded feedforward in which the disturbances are assumed to be unknown is considered here. Results from numerical simulations using mathematical models of both a free-free three-degree-of-freedom mass-spring-dashpot system and the XV-15 tiltrotor research aircraft are presented. In regulation mode operation, which calls for zero system response in the presence of disturbances, the simulations showed reductions of nearly 100%. In tracking mode operations, where the system is commanded to follow a specified path, the GPC controllers produced the desired responses, even in the presence of disturbances.

  18. A generalized framework for interactive dynamic simulation for MultiRigid bodies.

    PubMed

    Son, Wookho; Kim, Kyunghwan; Amato, Nancy M; Trinkle, Jeffrey C

    2004-04-01

    This paper presents a generalized framework for dynamic simulation realized in a prototype simulator called the Interactive Generalized Motion Simulator (I-GMS), which can simulate motions of multirigid-body systems with contact interaction in virtual environments. I-GMS is designed to meet two important goals: generality and interactivity. By generality, we mean a dynamic simulator which can easily support various systems of rigid bodies, ranging from a single free-flying rigid object to complex linkages such as those needed for robotic systems or human body simulation. To provide this generality, we have developed I-GMS in an object-oriented framework. The user interactivity is supported through a haptic interface for articulated bodies, introducing interactive dynamic simulation schemes. This user-interaction is achieved by performing push and pull operations via the PHANToM haptic device, which runs as an integrated part of I-GMS. Also, a hybrid scheme was used for simulating internal contacts (between bodies in the multirigid-body system) in the presence of friction, which could avoid the nonexistent solution problem often faced when solving contact problems with Coulomb friction. In our hybrid scheme, two impulse-based methods are exploited so that different methods are applied adaptively, depending on whether the current contact situation is characterized as "bouncing" or "steady." We demonstrate the user-interaction capability of I-GMS through on-line editing of trajectories of a 6-degree of freedom (dof) articulated structure.

  19. Respiratory motion correction in gated cardiac SPECT using quaternion-based, rigid-body registration.

    PubMed

    Parker, Jason G; Mair, Bernard A; Gilland, David R

    2009-10-01

    In this article, a new method is introduced for estimating the motion of the heart due to respiration in gated cardiac SPECT using a rigid-body model with rotation parametrized by a unit quaternion. The method is based on minimizing the sum of squared errors between the reference and the deformed frames resulting from the usual optical flow constraint by using an optimized conjugate gradient routine. This method does not require any user-defined parameters or penalty terms, which simplifies its use in a clinical setting. Using a mathematical phantom, the method was quantitatively compared to the principal axis method, as well as an iterative method in which the rotation matrix was represented by Euler angles. The quaternion-based method was shown to be substantially more accurate and robust across a wide range of extramyocardial activity levels than the principal axis method. Compared with the Euler angle representation, the quaternion-based method resulted in similar accuracy but a significant reduction in computation times. Finally, the quaternion-based method was investigated using a respiratory-gated cardiac SPECT acquisition of a human subject. The motion-corrected image has increased sharpness and myocardial uniformity compared to the uncorrected image.

  20. Comparison of similarity measures for rigid-body CT/Dual X-ray image registrations.

    PubMed

    Kim, Jinkoo; Li, Shidong; Pradhan, Deepak; Hammoud, Rabih; Chen, Qing; Yin, Fang-Fang; Zhao, Yang; Kim, Jae Ho; Movsas, Benjamin

    2007-08-01

    A set of experiments were conducted to evaluate six similarity measures for intensity-based rigid-body 3D/2D image registration. Similarity measure is an index that measures the similarity between a digitally reconstructed radiograph (DRR) and an x-ray planar image. The registration is accomplished by maximizing the sum of the similarity measures between biplane x-ray images and the corresponding DRRs in an iterative fashion. We have evaluated the accuracy and attraction ranges of the registrations using six different similarity measures on phantom experiments for head, thorax, and pelvis. The images were acquired using Varian Medial System On-Board Imager. Our results indicated that normalized cross correlation and entropy of difference showed a wide attraction range (62 deg and 83 mm mean attraction range, omega(mean)), but the worst accuracy (4.2 mm maximum error, e(max)). The gradient-based similarity measures, gradient correlation and gradient difference, and the pattern intensity showed sub-millimeter accuracy, but narrow attraction ranges (omega(mean)=29 deg, 31 mm). Mutual information was in-between of these two groups (e(max)=2.5 mm, omega(mean)= 48 deg, 52 mm). On the data of 120 x-ray pairs from eight IRB approved prostate patients, the gradient difference showed the best accuracy. In the clinical applications, registrations starting with the mutual information followed by the gradient difference may provide the best accuracy and the most robustness.

  1. A simple molecular mechanics integrator in mixed rigid body and dihedral angle space

    PubMed Central

    Vitalis, Andreas; Pappu, Rohit V.

    2014-01-01

    We propose a numerical scheme to integrate equations of motion in a mixed space of rigid-body and dihedral angle coordinates. The focus of the presentation is biomolecular systems and the framework is applicable to polymers with tree-like topology. By approximating the effective mass matrix as diagonal and lumping all bias torques into the time dependencies of the diagonal elements, we take advantage of the formal decoupling of individual equations of motion. We impose energy conservation independently for every degree of freedom and this is used to derive a numerical integration scheme. The cost of all auxiliary operations is linear in the number of atoms. By coupling the scheme to one of two popular thermostats, we extend the method to sample constant temperature ensembles. We demonstrate that the integrator of choice yields satisfactory stability and is free of mass-metric tensor artifacts, which is expected by construction of the algorithm. Two fundamentally different systems, viz., liquid water and an α-helical peptide in a continuum solvent are used to establish the applicability of our method to a wide range of problems. The resultant constant temperature ensembles are shown to be thermodynamically accurate. The latter relies on detailed, quantitative comparisons to data from reference sampling schemes operating on exactly the same sets of degrees of freedom. PMID:25053299

  2. Rigid body Brownian dynamics as a tool for studying ion channel blockers.

    PubMed

    Gordon, Dan; Chen, Rong; Ho, Junming; Coote, Michelle L; Chung, Shin-Ho

    2012-02-16

    Using a novel rigid body Brownian dynamics algorithm, we investigate how a spherically asymmetrical polyamine molecule, a branched analogue of spermine, interacts with the external vestibule of the voltage-gated potassium channel, Kv1.2. Simulations reveal that the blocker, with a charge of +4e, inserts one of its charged amine groups into the selectivity filter, while another forms a salt bridge with an aspartate residue located just outside the entrance of the pore. This binding mode mimics features of the binding of polypeptides such as the scorpion venom charybdotoxin to the channel. The potential of mean force constructed with Brownian dynamics is a reasonable match to that obtained from molecular dynamics simulations, with dissociation constants of 4.7 and 22 μM, respectively. The current-voltage relationships obtained with and without a blocker in the external reservoir show that the inward current is severely attenuated by the presence of the blocker, whereas the outward current is only moderately reduced. The computational molecular modeling technique we introduce here can provide detailed insights into ligand-channel interactions and can be used for rapidly screening potential blocker molecules.

  3. Fullrmc, a rigid body reverse monte carlo modeling package enabled with machine learning and artificial intelligence

    DOE PAGES

    Aoun, Bachir

    2016-01-22

    Here, a new Reverse Monte Carlo (RMC) package ‘fullrmc’ for atomic or rigid body and molecular, amorphous or crystalline materials is presented. fullrmc main purpose is to provide a fully modular, fast and flexible software, thoroughly documented, complex molecules enabled, written in a modern programming language (python, cython ,C and C++ when performance is needed) and complying to modern programming practices. fullrmc approach in solving an atomic or molecular structure is different from existing RMC algorithms and software. In a nutshell, traditional RMC methods and software randomly adjust atom positions until the whole system has the greatest consistency with amore » set of experimental data. In contrast, fullrmc applies smart moves endorsed with reinforcement machine learning to groups of atoms. While fullrmc allows running traditional RMC modelling, the uniqueness of this approach resides in its ability to customize grouping atoms in any convenient way with no additional programming efforts and to apply smart and more physically meaningful moves to the defined groups of atoms. Also fullrmc provides a unique way with almost no additional computational cost to recur a group’s selection, allowing the system to go out of local minimas by refining a group’s position or exploring through and beyond not allowed positions and energy barriers the unrestricted three dimensional space around a group.« less

  4. Fullrmc, a rigid body reverse monte carlo modeling package enabled with machine learning and artificial intelligence

    SciTech Connect

    Aoun, Bachir

    2016-01-22

    Here, a new Reverse Monte Carlo (RMC) package ‘fullrmc’ for atomic or rigid body and molecular, amorphous or crystalline materials is presented. fullrmc main purpose is to provide a fully modular, fast and flexible software, thoroughly documented, complex molecules enabled, written in a modern programming language (python, cython ,C and C++ when performance is needed) and complying to modern programming practices. fullrmc approach in solving an atomic or molecular structure is different from existing RMC algorithms and software. In a nutshell, traditional RMC methods and software randomly adjust atom positions until the whole system has the greatest consistency with a set of experimental data. In contrast, fullrmc applies smart moves endorsed with reinforcement machine learning to groups of atoms. While fullrmc allows running traditional RMC modelling, the uniqueness of this approach resides in its ability to customize grouping atoms in any convenient way with no additional programming efforts and to apply smart and more physically meaningful moves to the defined groups of atoms. Also fullrmc provides a unique way with almost no additional computational cost to recur a group’s selection, allowing the system to go out of local minimas by refining a group’s position or exploring through and beyond not allowed positions and energy barriers the unrestricted three dimensional space around a group.

  5. Alternating Access in Maltose Transporter Mediated by Rigid-Body Rotations

    SciTech Connect

    Khare, Dheeraj; Oldham, Michael L.; Orelle, Cedric; Davidson, Amy L.; Chen, Jue; Purdue

    2010-07-27

    ATP-binding cassette transporters couple ATP hydrolysis to substrate translocation through an alternating access mechanism, but the nature of the conformational changes in a transport cycle remains elusive. Previously we reported the structure of the maltose transporter MalFGK{sub 2} in an outward-facing conformation in which the transmembrane (TM) helices outline a substrate-binding pocket open toward the periplasmic surface and ATP is poised for hydrolysis along the closed nucleotide-binding dimer interface. Here we report the structure of the nucleotide-free maltose transporter in which the substrate binding pocket is only accessible from the cytoplasm and the nucleotide-binding interface is open. Comparison of the same transporter crystallized in two different conformations reveals that alternating access involves rigid-body rotations of the TM subdomains that are coupled to the closure and opening of the nucleotide-binding domain interface. The comparison also reveals that point mutations enabling binding protein-independent transport line dynamic interfaces in the TM region.

  6. The Effect of Water Compressibility on a Rigid Body Movement in Two Phase Flow

    NASA Astrophysics Data System (ADS)

    Park, Chan Wook; Kim, Hak Sun; Lee, Sungsu

    2008-11-01

    The motion of a rigid body in a tube full of water-filled, initiated by a sudden release of highly pressurized air is simulated presuming the flow field as a two dimensional one. The effects of water compressibility on the body movement are investigated, comparing results based on the Fluent VOF model where water is treated as an incompressible medium with those from the presently developed VOF scheme. The present model considers compressibility of both air and water. The Fluent results show that the body moves farther and at higher speeds than the present ones. As time proceeds, the relative difference of speed and displacement between the two results drops substantially, after acoustic waves in water traverse and return the full length of the tube several times. To estimate instantaneous accelerations, however, requires implementation of the water compressibility effect as discrepancies between them do not decrease even after several pressure wave cycles. This work was supported by a research fund granted from Agency for Defense Development, South Korea.

  7. Respiratory motion correction in gated cardiac SPECT using quaternion-based, rigid-body registration

    PubMed Central

    Parker, Jason G.; Mair, Bernard A.; Gilland, David R.

    2009-01-01

    In this article, a new method is introduced for estimating the motion of the heart due to respiration in gated cardiac SPECT using a rigid-body model with rotation parametrized by a unit quaternion. The method is based on minimizing the sum of squared errors between the reference and the deformed frames resulting from the usual optical flow constraint by using an optimized conjugate gradient routine. This method does not require any user-defined parameters or penalty terms, which simplifies its use in a clinical setting. Using a mathematical phantom, the method was quantitatively compared to the principal axis method, as well as an iterative method in which the rotation matrix was represented by Euler angles. The quaternion-based method was shown to be substantially more accurate and robust across a wide range of extramyocardial activity levels than the principal axis method. Compared with the Euler angle representation, the quaternion-based method resulted in similar accuracy but a significant reduction in computation times. Finally, the quaternion-based method was investigated using a respiratory-gated cardiac SPECT acquisition of a human subject. The motion-corrected image has increased sharpness and myocardial uniformity compared to the uncorrected image. PMID:19928105

  8. Stiffness-generated rigid-body mode shapes for Lanczos eigensolution with SUPORT DOF by way of a MSC/NASTRAN DMAP alter

    NASA Technical Reports Server (NTRS)

    Abdallah, Ayman A.; Barnett, Alan R.; Widrick, Timothy W.; Manella, Richard T.; Miller, Robert P.

    1994-01-01

    When using all MSC/NASTRAN eigensolution methods except Lanczos, the analyst can replace the coupled system rigid-body modes calculated within DMAP module READ with mass orthogonalized and normalized rigid-body modes generated from the system stiffness. This option is invoked by defining MSC/NASTRAN r-set degrees of freedom via the SUPORT bulk data card. The newly calculated modes are required if the rigid-body modes calculated by the eigensolver are not 'clean' due to numerical roundoffs in the solution. When performing transient structural dynamic load analysis, the numerical roundoffs can result in inaccurate rigid-body accelerations which affect steady-state responses. Unfortunately, when using the Lanczos method and defining r-set degrees of freedom, the rigid-body modes calculated within DMAP module REIGL are retained. To overcome this limitation and to allow MSC/NASTRAN to handle SUPORT degrees of freedom identically for all eigensolvers, a DMAP Alter has been written which replaces Lanczos-calculated rigid-body modes with stiffness-generated rigid-body modes. The newly generated rigid-body modes are normalized with respect to the system mass and orthogonalized using the Gram-Schmidt technique. This algorithm has been implemented as an enhancement to an existing coupled loads methodology.

  9. Curvilinear Immersed Boundary Method for Simulating Fluid Structure Interaction with Complex 3D Rigid Bodies

    PubMed Central

    Borazjani, Iman; Ge, Liang; Sotiropoulos, Fotis

    2010-01-01

    The sharp-interface CURVIB approach of Ge and Sotiropoulos [L. Ge, F. Sotiropoulos, A Numerical Method for Solving the 3D Unsteady Incompressible Navier-Stokes Equations in Curvilinear Domains with Complex Immersed Boundaries, Journal of Computational Physics 225 (2007) 1782–1809] is extended to simulate fluid structure interaction (FSI) problems involving complex 3D rigid bodies undergoing large structural displacements. The FSI solver adopts the partitioned FSI solution approach and both loose and strong coupling strategies are implemented. The interfaces between immersed bodies and the fluid are discretized with a Lagrangian grid and tracked with an explicit front-tracking approach. An efficient ray-tracing algorithm is developed to quickly identify the relationship between the background grid and the moving bodies. Numerical experiments are carried out for two FSI problems: vortex induced vibration of elastically mounted cylinders and flow through a bileaflet mechanical heart valve at physiologic conditions. For both cases the computed results are in excellent agreement with benchmark simulations and experimental measurements. The numerical experiments suggest that both the properties of the structure (mass, geometry) and the local flow conditions can play an important role in determining the stability of the FSI algorithm. Under certain conditions unconditionally unstable iteration schemes result even when strong coupling FSI is employed. For such cases, however, combining the strong-coupling iteration with under-relaxation in conjunction with the Aitken’s acceleration technique is shown to effectively resolve the stability problems. A theoretical analysis is presented to explain the findings of the numerical experiments. It is shown that the ratio of the added mass to the mass of the structure as well as the sign of the local time rate of change of the force or moment imparted on the structure by the fluid determine the stability and convergence of the

  10. Point-based rigid-body registration using an unscented Kalman filter.

    PubMed

    Moghari, Mehdi Hedjazi; Abolmaesumi, Purang

    2007-12-01

    We present and validate a novel registration algorithm mapping two data sets, generated from a rigid object, in the presence of Gaussian noise. The proposed method is based on the Unscented Kalman Filter (UKF) algorithm that is generally employed for analyzing nonlinear systems corrupted by additive Gaussian noise. First, we employ our proposed registration algorithm to fit two randomly generated data sets in the presence of isotropic Gaussian noise, when the corresponding points between the two data sets are assumed to be known. Then, we extend the registration method to the case where the data (with known correspondences) is stimulated by anisotropic Gaussian noise. The new registration method not only reliably converges to the correct registration solution, but it also estimates the variance, as a confidence measure, for each of the estimated registration transformation parameters. Furthermore, we employ the proposed registration algorithm for rigid-body, point-based registration where corresponding points between two registering data sets are unknown. The algorithm is tested on point data sets which are garnered from a pelvic cadaver and a scaphoid bone phantom by means of computed tomography (CT) and tracked free-hand ultrasound imaging. The collected 3-D points in the ultrasound frame are registered to the 3-D meshes in the CT frame by using the proposed and the standard Iterative Closest Points (ICP) registration algorithms. Experimental results demonstrate that our proposed method significantly outperforms the ICP registration algorithm in the presence of additive Gaussian noise. It is also shown that the proposed registration algorithm is more robust than the ICP registration algorithm in terms of outliers in data sets and initial misalignment between the two data sets.

  11. Lie theory, Riemannian geometry, and the dynamics of coupled rigid bodies

    NASA Astrophysics Data System (ADS)

    Park, F. C.; Kim, M. W.

    In this article we formulate, in a Lie group setting, the equations of motion for a system of n coupled rigid bodies subject to holonomic constraints. A mapping f: { l {M} -> l {N} is constructed, where l M is the m-dimensional configuration manifold of the system, and l{N} = {SE(3)} × ots × {SE(3)} (n copies) is endowed with the left-invariant Riemannian metric h corresponding to the total kinetic energy of the system, where SE(3) is the special Euclidean group. The generalized inertia tensor of the system is given by the pullback metric f*h; the equations of motion are then the geodesic equations on l M with respect to this metric. We show how this coordinate-free formulation leads directly to a factorization of the generalized inertia tensor of the form {l S}T {l L}T {l H} {l L} {l S}, where l S is a constant block-diagonal matrix consisting only of kinematic parameters, H is a constant block-diagonal matrix consisting only of inertial parameters, and {l L} is a block lower-triangular matrix composed of Adjoint operators on se(3). Such a factorization is useful for various multibody system dynamics applications, e.g., inertial parameter identification, adaptive control, and design optimization. We also show how in many practical situations {l N} can be reduced to a submanifold, thereby considerably simplifying the derivation of the equations of motion. Our geometric formulation not only suggests ways to choose the best coordinates for analysis and computation, but also provides high-level insight into the structure of the equations of motion.

  12. Acoustic equations for a gas stream in rigid-body rotation

    NASA Astrophysics Data System (ADS)

    Garcia-Ybarra, Pedro L.; Marin-Antuña, Jose M.

    2017-02-01

    The classical topic of wave propagation in a rotating gas is revisited by deducing scalar wave equations for propagation of acoustic and rotational waves through a plug flow of gas in rigid-body rotation with arbitrary intensities of the radial stratification. In the light of these novel equations, wave propagation is analyzed in two different base gas states: isothermal and homentropic. In both cases, previous findings are recovered that assess the validity of the equations and new results are established. In the non-homentropic but isothermal case, the set of governing equations is reduced to two coupled scalar wave equations with space dependent coefficients for the disturbances of density and pressure. Travelling wave solutions with variable amplitude have been obtained in the limit of weak stratification both for inertial waves as for acoustic waves which, in general, propagate on different frequency bands that overlap in the small wavenumber region. Furthermore, the entropy stratification in the base state is stable and compels the propagation of internal waves, leading to hybrid acoustic-inertial-vortical modes. In the homentropic case, the adiabatic relation between pressure and density disturbances allows to reduce further the governing equations to a single fourth-order scalar wave equation. In this case, the sound propagation velocity depends on the distance to the rotation axis and solutions are found by multiple-scale analyses in the form of waves with slowly varying amplitude and wavenumber. The corresponding eikonal equation shows that acoustic rays are refracted towards the rotation axis, propagating and spinning along and around it. In that way, the swirling gas behaves as an axial waveguide trapping inside any acoustic ray propagating in the vortex with large enough azimuthal and/or vertical wavenumber component.

  13. Stability of the classical type of relative equilibria of a rigid body in the J 2 problem

    NASA Astrophysics Data System (ADS)

    Wang, Yue; Xu, Shijie

    2013-08-01

    The motion of a point mass in the J 2 problem is generalized to that of a rigid body in a J 2 gravity field. The linear and nonlinear stability of the classical type of relative equilibria of the rigid body, which have been obtained in our previous paper, are studied in the framework of geometric mechanics with the second-order gravitational potential. Non-canonical Hamiltonian structure of the problem, i.e., Poisson tensor, Casimir functions and equations of motion, are obtained through a Poisson reduction process by means of the symmetry of the problem. The linear system matrix at the relative equilibria is given through the multiplication of the Poisson tensor and Hessian matrix of the variational Lagrangian. Based on the characteristic equation of the linear system matrix, the conditions of linear stability of the relative equilibria are obtained. The conditions of nonlinear stability of the relative equilibria are derived with the energy-Casimir method through the projected Hessian matrix of the variational Lagrangian. With the stability conditions obtained, both the linear and nonlinear stability of the relative equilibria are investigated in details in a wide range of the parameters of the gravity field and the rigid body. We find that both the zonal harmonic J 2 and the characteristic dimension of the rigid body have significant effects on the linear and nonlinear stability. Similar to the classical attitude stability in a central gravity field, the linear stability region is also consisted of two regions that are analogues of the Lagrange region and the DeBra-Delp region respectively. The nonlinear stability region is the subset of the linear stability region in the first quadrant that is the analogue of the Lagrange region. Our results are very useful for the studies on the motion of natural satellites in our solar system.

  14. A vector-dyadic development of the equations of motion for N-coupled rigid bodies and point masses

    NASA Technical Reports Server (NTRS)

    Frisch, H. P.

    1974-01-01

    The equations of motion are derived, in vector-dyadic format, for a topological tree of coupled rigid bodies, point masses, and symmetrical momentum wheels. These equations were programmed, and form the basis for the general-purpose digital computer program N-BOD. A complete derivation of the equations of motion is included along with a description of the methods used for kinematics, constraint elimination, and for the inclusion of nongyroscope forces and torques acting external or internal to the system.

  15. Multiple-Zone Diffractive Optic Element for Laser Ranging Applications

    NASA Technical Reports Server (NTRS)

    Ramos-Izquierdo, Luis A.

    2011-01-01

    A diffractive optic element (DOE) can be used as a beam splitter to generate multiple laser beams from a single input laser beam. This technology has been recently used in LRO s Lunar Orbiter Laser Altimeter (LOLA) instrument to generate five laser beams that measure the lunar topography from a 50-km nominal mapping orbit (see figure). An extension of this approach is to use a multiple-zone DOE to allow a laser altimeter instrument to operate over a wider range of distances. In particular, a multiple-zone DOE could be used for applications that require both mapping and landing on a planetary body. In this case, the laser altimeter operating range would need to extend from several hundred kilometers down to a few meters. The innovator was recently involved in an investigation how to modify the LOLA instrument for the OSIRIS asteroid mapping and sample return mission. One approach is to replace the DOE in the LOLA laser beam expander assembly with a multiple-zone DOE that would allow for the simultaneous illumination of the asteroid with mapping and landing laser beams. The proposed OSIRIS multiple-zone DOE would generate the same LOLA five-beam output pattern for high-altitude topographic mapping, but would simultaneously generate a wide divergence angle beam using a small portion of the total laser energy for the approach and landing portion of the mission. Only a few percent of the total laser energy is required for approach and landing operations as the return signal increases as the inverse square of the ranging height. A wide divergence beam could be implemented by making the center of the DOE a diffractive or refractive negative lens. The beam energy and beam divergence characteristics of a multiple-zone DOE could be easily tailored to meet the requirements of other missions that require laser ranging data. Current single-zone DOE lithographic manufacturing techniques could also be used to fabricate a multiple-zone DOE by masking the different DOE zones during

  16. General Relativistic Elastic Body, Fluid,quasi-rigid Body, Quasi-liquid and Others in Multiple Coordinate Systems

    NASA Astrophysics Data System (ADS)

    Xu, Chongming

    2009-05-01

    The approximation method in multiple coordinate systems at first post Newtonian (1 PN) level has been established by Darmour, Soffel and Xu (Phys. Rev. D(PRD) 43, 3273 (1991);D 45, 1017(1992);D 47, 3124 (1993);D 49, 618 (1994)). Normally, to discuss an astronomical object (e.g. a star in binary systems or the earth in solar system) we need multiple coordinate systems, especially for precise astrometry 1 PN (some time even 2 PN) approximate method is required. As we know up to now the ideas on elastic body, fluid, rigid body and liquid in the framework of Newtonian physics are still very useful for understanding and calculating some practical problems. Although the general relativistic theories of elastic body, general relativistic hydrodynamics and post-Newtonian quasi-rigid body have been discussed by many authors (including our papers (PRD63, 043002(2001); D63, 064001(2001); D68, 064009(2003); D69, 024003(2004); D71,024030 (2005))), but there is no completing discussion on all of these ideas in a unified point view. The applications of these ideas in the general relativity are important in the research fields of astrometry and geophysics, especially in case precise measurements reach so higher level (millimicro arc sec). The extended relativistic versions of these ideas should be revised the Newtonian results. In this paper, we shall give a complete discussion on all of these ideas in 1 PN approximation. We shall clarify the ideas on perfect elastic material, quasi-rigid body, quasi-liquid and so on with some precise mathematical forms. For fluid we show the hydrodynamic equations of a non-perfect fluid in multiple coordinates systems (both local and global).

  17. Computer program for post-flight analysis of rigid body moments acting on a launch vehicle first stage

    NASA Technical Reports Server (NTRS)

    Knauber, R. N.

    1982-01-01

    A FORTRAN coded computer program and method for evaluation of the rigid body disturbing moments for a launch vehicle first stage based on post-flight measurements is described. The technique is a straightforward deterministic approach. Residual moments are computed to satisfy the equations of motion. Residuals are expressed in terms of altered vehicle characteristics; the aerodynamic coefficients, thrust misalignment, and control effectiveness. This method was used on the Scout launch vehicle and uncovered several significant differences between flight data and wind tunnel data. The computer program is written in FORTRAN IV for a CDC CYBER 173 computer system.

  18. Stability of high-frequency periodic motions of a heavy rigid body with a horizontally vibrating suspension point

    NASA Astrophysics Data System (ADS)

    Belichenko, M. V.

    2016-11-01

    The motion of a heavy rigid body one of whose points (the suspension point) executes horizontal harmonic high-frequency vibrations with small amplitude is considered. The problem of existence of high-frequency periodic motions with period equal to the period of the suspension point vibrations is considered. The stability conditions for the revealed motions are obtained in the linear approximation. The following three special cases of mass distribution in the body are considered; a body whose center of mass lies on the principal axis of inertia, a body whose center of mass lies in the principal plane of inertia, and a dynamically symmetric body.

  19. Protein-protein interaction network prediction by using rigid-body docking tools: application to bacterial chemotaxis.

    PubMed

    Matsuzaki, Yuri; Ohue, Masahito; Uchikoga, Nobuyuki; Akiyama, Yutaka

    2014-01-01

    Core elements of cell regulation are made up of protein-protein interaction (PPI) networks. However, many parts of the cell regulatory systems include unknown PPIs. To approach this problem, we have developed a computational method of high-throughput PPI network prediction based on all-to-all rigid-body docking of protein tertiary structures. The prediction system accepts a set of data comprising protein tertiary structures as input and generates a list of possible interacting pairs from all the combinations as output. A crucial advantage of this docking based method is in providing predictions of protein pairs that increases our understanding of biological pathways by analyzing the structures of candidate complex structures, which gives insight into novel interaction mechanisms. Although such exhaustive docking calculation requires massive computational resources, recent advancements in the computational sciences have made such large-scale calculations feasible. In this study we applied our prediction method to a pathway reconstruction problem of bacterial chemotaxis by using two different rigid-body docking tools with different scoring models. We found that the predicted interactions were different between the results from the two tools. When the positive predictions from both of the docking tools were combined, all the core signaling interactions were correctly predicted with the exception of interactions activated by protein phosphorylation. Large-scale PPI prediction using tertiary structures is an effective approach that has a wide range of potential applications. This method is especially useful for identifying novel PPIs of new pathways that control cellular behavior.

  20. A conservative coupling algorithm between a compressible flow and a rigid body using an Embedded Boundary method

    NASA Astrophysics Data System (ADS)

    Monasse, L.; Daru, V.; Mariotti, C.; Piperno, S.; Tenaud, C.

    2012-04-01

    This paper deals with a new solid-fluid coupling algorithm between a rigid body and an unsteady compressible fluid flow, using an Embedded Boundary method. The coupling with a rigid body is a first step towards the coupling with a Discrete Element method. The flow is computed using a finite volume approach on a Cartesian grid. The expression of numerical fluxes does not affect the general coupling algorithm and we use a one-step high-order scheme proposed by Daru and Tenaud [V. Daru, C. Tenaud, J. Comput. Phys. (2004)]. The Embedded Boundary method is used to integrate the presence of a solid boundary in the fluid. The coupling algorithm is totally explicit and ensures exact mass conservation and a balance of momentum and energy between the fluid and the solid. It is shown that the scheme preserves uniform movement of both fluid and solid and introduces no numerical boundary roughness. The efficiency of the method is demonstrated on challenging one- and two-dimensional benchmarks.

  1. Numerical model (switchable/dual model) of the human head for rigid body and finite elements applications.

    PubMed

    Tabacu, Stefan

    2015-01-01

    In this paper, a methodology for the development and validation of a numerical model of the human head using generic procedures is presented. All steps required, starting with the model generation, model validation and applications will be discussed. The proposed model may be considered as a dual one due to its capabilities to switch from deformable to a rigid body according to the application's requirements. The first step is to generate the numerical model of the human head using geometry files or medical images. The required stiffness and damping for the elastic connection used for the rigid body model are identified by performing a natural frequency analysis. The presented applications for model validation are related to impact analysis. The first case is related to Nahum's (Nahum and Smith 1970) experiments pressure data being evaluated and a pressure map generated using the results from discrete elements. For the second case, the relative displacement between the brain and the skull is evaluated according to Hardy's (Hardy WH, Foster CD, Mason, MJ, Yang KH, King A, Tashman S. 2001.Investigation of head injury mechanisms using neutral density technology and high-speed biplanar X-ray. Stapp Car Crash J. 45:337-368, SAE Paper 2001-22-0016) experiments. The main objective is to validate the rigid model as a quick and versatile tool for acquiring the input data for specific brain analyses.

  2. Deformable registration for image-guided spine surgery: preserving rigid body vertebral morphology in free-form transformations

    NASA Astrophysics Data System (ADS)

    Reaungamornrat, S.; Wang, A. S.; Uneri, A.; Otake, Y.; Zhao, Z.; Khanna, A. J.; Siewerdsen, J. H.

    2014-03-01

    Purpose: Deformable registration of preoperative and intraoperative images facilitates accurate localization of target and critical anatomy in image-guided spine surgery. However, conventional deformable registration fails to preserve the morphology of rigid bone anatomy and can impart distortions that confound high-precision intervention. We propose a constrained registration method that preserves rigid morphology while allowing deformation of surrounding soft tissues. Method: The registration method aligns preoperative 3D CT to intraoperative cone-beam CT (CBCT) using free-form deformation (FFD) with penalties on rigid body motion imposed according to a simple intensity threshold. The penalties enforced 3 properties of a rigid transformation - namely, constraints on affinity (AC), orthogonality (OC), and properness (PC). The method also incorporated an injectivity constraint (IC) to preserve topology. Physical experiments (involving phantoms, an ovine spine, and a human cadaver) as well as digital simulations were performed to evaluate the sensitivity to registration parameters, preservation of rigid body morphology, and overall registration accuracy of constrained FFD in comparison to conventional unconstrained FFD (denoted uFFD) and Demons registration. Result: FFD with orthogonality and injectivity constraints (denoted FFD+OC+IC) demonstrated improved performance compared to uFFD and Demons. Affinity and properness constraints offered little or no additional improvement. The FFD+OC+IC method preserved rigid body morphology at near-ideal values of zero dilatation (D = 0.05, compared to 0.39 and 0.56 for uFFD and Demons, respectively) and shear (S = 0.08, compared to 0.36 and 0.44 for uFFD and Demons, respectively). Target registration error (TRE) was similarly improved for FFD+OC+IC (0.7 mm), compared to 1.4 and 1.8 mm for uFFD and Demons. Results were validated in human cadaver studies using CT and CBCT images, with FFD+OC+IC providing excellent preservation

  3. A boundary integral approach to analyze the viscous scattering of a pressure wave by a rigid body

    PubMed Central

    Homentcovschi, Dorel; Miles, Ronald N.

    2008-01-01

    The paper provides boundary integral equations for solving the problem of viscous scattering of a pressure wave by a rigid body. By using this mathematical tool uniqueness and existence theorems are proved. Since the boundary conditions are written in terms of velocities, vector boundary integral equations are obtained for solving the problem. The paper introduces single-layer viscous potentials and also a stress tensor. Correspondingly, a viscous double-layer potential is defined. The properties of all these potentials are investigated. By representing the scattered field as a combination of a single-layer viscous potential and a double-layer viscous potential the problem is reduced to the solution of a singular vectorial integral equation of Fredholm type of the second kind. In the case where the stress vector on the boundary is the main quantity of interest the corresponding boundary singular integral equation is proved to have a unique solution. PMID:18709178

  4. Influence of viscosity on the scattering of an air pressure wave by a rigid body: a regular boundary integral formulation

    PubMed Central

    Homentcovschi, Dorel

    2008-01-01

    This paper gives a regular vector boundary integral equation for solving the problem of viscous scattering of a pressure wave by a rigid body. Firstly, single-layer viscous potentials and a generalized stress tensor are introduced. Correspondingly, generalized viscous double-layer potentials are defined. By representing the scattered field as a combination of a single-layer viscous potential and a generalized viscous double-layer potential, the problem is reduced to the solution of a vectorial Fredholm integral equation of the second kind. Generally, the vector integral equation is singular. However, there is a particular stress tensor, called pseudostress, which yields a regular integral equation. In this case, the Fredholm alternative applies and permits a direct proof of the existence and uniqueness of the solution. The results presented here provide the foundation for a numerical solution procedure. PMID:19865494

  5. mtsslSuite: In silico spin labelling, trilateration and distance-constrained rigid body docking in PyMOL

    NASA Astrophysics Data System (ADS)

    Hagelueken, Gregor; Abdullin, Dinar; Ward, Richard; Schiemann, Olav

    2013-10-01

    Nanometer distance measurements based on electron paramagnetic resonance methods in combination with site-directed spin labelling are powerful tools for the structural analysis of macromolecules. The software package mtsslSuite provides scientists with a set of tools for the translation of experimental distance distributions into structural information. The package is based on the previously published mtsslWizard software for in silico spin labelling. The mtsslSuite includes a new version of MtsslWizard that has improved performance and now includes additional types of spin labels. Moreover, it contains applications for the trilateration of paramagnetic centres in biomolecules and for rigid-body docking of subdomains of macromolecular complexes. The mtsslSuite is tested on a number of challenging test cases and its strengths and weaknesses are evaluated.

  6. Automatism

    PubMed Central

    McCaldon, R. J.

    1964-01-01

    Individuals can carry out complex activity while in a state of impaired consciousness, a condition termed “automatism”. Consciousness must be considered from both an organic and a psychological aspect, because impairment of consciousness may occur in both ways. Automatism may be classified as normal (hypnosis), organic (temporal lobe epilepsy), psychogenic (dissociative fugue) or feigned. Often painstaking clinical investigation is necessary to clarify the diagnosis. There is legal precedent for assuming that all crimes must embody both consciousness and will. Jurists are loath to apply this principle without reservation, as this would necessitate acquittal and release of potentially dangerous individuals. However, with the sole exception of the defence of insanity, there is at present no legislation to prohibit release without further investigation of anyone acquitted of a crime on the grounds of “automatism”. PMID:14199824

  7. Digital holography for mechanical vibration measurements in rigid body displacement: elimination of the latter by means of a variable focal length adjustment

    NASA Astrophysics Data System (ADS)

    Pérez-López, Carlos; Mendoza Santoyo, Fernando; Gutiérrez Hernández, David Asael; Muñoz Solis, Silvino

    2008-06-01

    We present our investigation on the separation of mechanical vibrations from rigid body displacements. Pairs of digital holograms acquired between two consecutive time intervals from this type of events produce phase maps that contain both the vibration and rigid body motion information, or even further fully decorrelated phase maps after computer processing. In order to compensate for body displacements, a conjugate object-image experimental arrangement for digital holography is used to measure the mechanical vibrations in a rectangular flat plate. This is achieved by including an extra lens with variable focal length adjustments in front of the typical lens-aperture combination used in the optical head of a digital holographic set up. Out of plane data is obtained from a framed metal plate subjected to a known modal vibration that is also allowed to move perpendicularly to its surface. We will demonstrate that due to the power adjustment of the added lens the angular phase change in the digital hologram from the known object motion allows the separation of the vibration mode at the image plane. The proposed lens addition into a new optical head arrangement in digital holography combined with an a priori knowledge of the rigid body displacement is able to accurately separate the mechanical vibrations making it a promising method in experiments performed under noisy environments. This research suggests the inclusion of adaptive lenses to control the effective focal length when there is a need to separate two distinctive motion types, i.e., vibration from rigid body motion.

  8. Estimating the Error of an Asymptotic Solution Describing the Angular Oscillations of the Axis of Symmetry of a Rotating Rigid Body

    NASA Astrophysics Data System (ADS)

    Konosevich, B. I.

    2014-07-01

    The error of the Wentzel-Kramers-Brillouin solution of the equations describing the angular motion of the axis of symmetry of rotation of a rigid body (projectile) is estimated. It is established that order of this estimate does not depend on whether the low-frequency oscillations of the axis of symmetry are damped or not

  9. Analogies between the Torque-Free Motion of a Rigid Body about a Fixed Point and Light Propagation in Anisotropic Media

    ERIC Educational Resources Information Center

    Bellver-Cebreros, Consuelo; Rodriguez-Danta, Marcelo

    2009-01-01

    An apparently unnoticed analogy between the torque-free motion of a rotating rigid body about a fixed point and the propagation of light in anisotropic media is stated. First, a new plane construction for visualizing this torque-free motion is proposed. This method uses an intrinsic representation alternative to angular momentum and independent of…

  10. An improved understanding of the natural resonances of moonpools contained within floating rigid-bodies: Theory and application to oscillating water column devices

    SciTech Connect

    Bull, Diana L.

    2015-09-23

    The fundamental interactions between waves, a floating rigid-body, and a moonpool that is selectively open to atmosphere or enclosed to purposefully induce pressure fluctuations are investigated. The moonpool hydrodynamic characteristics and the hydrodynamic coupling to the rigid-body are derived implicitly through reciprocity relations on an array of field points. By modeling the free surface of the moonpool in this manner, an explicit hydrodynamic coupling term is included in the equations of motion. This coupling results in the migration of the moonpool's natural resonance frequency from the piston frequency to a new frequency when enclosed in a floating rigid-body. Two geometries that highlight distinct aspects of marine vessels and oscillating water column (OWC) renewable energy devices are analyzed to reveal the coupled natural resonance migration. The power performance of these two OWCs in regular waves is also investigated. The air chamber is enclosed and a three-dimensional, linear, frequency domain performance model that links the rigid-body to the moonpool through a linear resistive control strategy is detailed. Furthermore, an analytic expression for the optimal linear resistive control values in regular waves is presented.

  11. An improved understanding of the natural resonances of moonpools contained within floating rigid-bodies: Theory and application to oscillating water column devices

    DOE PAGES

    Bull, Diana L.

    2015-09-23

    The fundamental interactions between waves, a floating rigid-body, and a moonpool that is selectively open to atmosphere or enclosed to purposefully induce pressure fluctuations are investigated. The moonpool hydrodynamic characteristics and the hydrodynamic coupling to the rigid-body are derived implicitly through reciprocity relations on an array of field points. By modeling the free surface of the moonpool in this manner, an explicit hydrodynamic coupling term is included in the equations of motion. This coupling results in the migration of the moonpool's natural resonance frequency from the piston frequency to a new frequency when enclosed in a floating rigid-body. Two geometriesmore » that highlight distinct aspects of marine vessels and oscillating water column (OWC) renewable energy devices are analyzed to reveal the coupled natural resonance migration. The power performance of these two OWCs in regular waves is also investigated. The air chamber is enclosed and a three-dimensional, linear, frequency domain performance model that links the rigid-body to the moonpool through a linear resistive control strategy is detailed. Furthermore, an analytic expression for the optimal linear resistive control values in regular waves is presented.« less

  12. A heterogeneous system based on GPU and multi-core CPU for real-time fluid and rigid body simulation

    NASA Astrophysics Data System (ADS)

    da Silva Junior, José Ricardo; Gonzalez Clua, Esteban W.; Montenegro, Anselmo; Lage, Marcos; Dreux, Marcelo de Andrade; Joselli, Mark; Pagliosa, Paulo A.; Kuryla, Christine Lucille

    2012-03-01

    Computational fluid dynamics in simulation has become an important field not only for physics and engineering areas but also for simulation, computer graphics, virtual reality and even video game development. Many efficient models have been developed over the years, but when many contact interactions must be processed, most models present difficulties or cannot achieve real-time results when executed. The advent of parallel computing has enabled the development of many strategies for accelerating the simulations. Our work proposes a new system which uses some successful algorithms already proposed, as well as a data structure organisation based on a heterogeneous architecture using CPUs and GPUs, in order to process the simulation of the interaction of fluids and rigid bodies. This successfully results in a two-way interaction between them and their surrounding objects. As far as we know, this is the first work that presents a computational collaborative environment which makes use of two different paradigms of hardware architecture for this specific kind of problem. Since our method achieves real-time results, it is suitable for virtual reality, simulation and video game fluid simulation problems.

  13. The planar restricted three-body problem when both primaries are triaxial rigid bodies: Equilibrium points and periodic orbits

    NASA Astrophysics Data System (ADS)

    Elshaboury, S. M.; Abouelmagd, Elbaz I.; Kalantonis, V. S.; Perdios, E. A.

    2016-09-01

    The restricted three-body problem when the primaries are triaxial rigid bodies is considered and its basic dynamical features are studied. In particular, the equilibrium points are identified as well as their stability is determined in the special case when the Euler angles of rotational motion are accordingly θi = ψi = π/2 and φi = π/2, i = 1, 2. It is found that three unstable collinear equilibrium points exist and two triangular such points which may be stable. Special attention has also been paid to the study of simple symmetric periodic orbits and 31 families consisting of such orbits have been determined. It has been found that only one of these families consists entirely of unstable members while the remaining families contain stable parts indicating that other families bifurcate from them. Finally, using the grid-search technique a global solution in the space of initial conditions is obtained which comprises simple and of higher multiplicities symmetric periodic orbits as well as escape and collision orbits.

  14. Governing equations of multi-component rigid body-spring discrete element models of reinforced concrete columns

    NASA Astrophysics Data System (ADS)

    Guan, P. B.; Tingatinga, E. A.; Longalong, R. E.; Saguid, J.

    2016-09-01

    During the past decades, the complexity of conventional methods to perform seismic performance assessment of buildings led to the development of more effective approaches. The rigid body spring-discrete element method (RBS-DEM) is one of these approaches and has recently been applied to the study of the behavior of reinforced concrete (RC) buildings subjected to strong earthquakes. In this paper, the governing equations of RBS-DEM planar elements subjected to lateral loads and horizontal ground motion are presented and used to replicate the hysteretic behavior of experimental RC columns. The RBS-DEM models of columns are made up of rigid components connected by systems of springs that simulate axial, shear, and bending behavior of an RC section. The parameters of springs were obtained using Response-2000 software and the hysteretic response of the models of select columns from the Pacific Earthquake Engineering Research (PEER) Structural Performance Database were computed numerically. Numerical examples show that one-component models were able to simulate the initial stiffness reasonably, while the displacement capacity of actual columns undergoing large displacements were underestimated.

  15. In-plane rigid-body vibration mode characterization with a nanometer resolution by stroboscopic imaging of a microstructured pattern.

    PubMed

    Sandoz, Patrick; Friedt, Jean-Michel; Carry, Emile

    2007-02-01

    This article introduces an improved approach for the characterization of in-plane rigid-body vibration, based on digital processing of stroboscopic images of the moving part. The method involves a sample preparation step, in order to pattern a periodic microstructure on the vibrating device, for instance, by focused ion beam milling. An image processing method has then been developed to perform the optimum reconstruction of this a priori known object feature. In-plane displacement and rotation are deduced simultaneously with a high resolution (10-2 pixel and 0.5 x 10(-3) rad, respectively). The measurement principle combines phase measurements-that provide the high resolution-with correlation-that unwraps the phase with the proper phase constants. The vibration modes of a tuning fork are used for demonstrating the capabilities of the method. For applications allowing the sample preparation, the proposed methodology is more convenient than common interference methods or image processing techniques for the characterization of the vibration modes, even for amplitudes in the nanometer range.

  16. A topological classification of the Chaplygin systems in the dynamics of a rigid body in a fluid

    SciTech Connect

    Nikolaenko, S S

    2014-02-28

    The paper is concerned with the topological analysis of the Chaplygin integrable case in the dynamics of a rigid body in a fluid. A full list of the topological types of Chaplygin systems in their dependence on the energy level is compiled on the basis of the Fomenko-Zieschang theory. An effective description of the topology of the Liouville foliation in terms of natural coordinate variables is also presented, which opens a direct way to calculating topological invariants. It turns out that on all nonsingular energy levels Chaplygin systems are Liouville equivalent to the well-known Euler case in the dynamics of a rigid body with fixed point. Bibliography: 23 titles.

  17. A review of a method for dynamic load distribution, dynamical modeling, and explicit internal force control when two manipulators mutually lift and transport a rigid body object

    SciTech Connect

    Unseren, M.A.

    1997-04-20

    The paper reviews a method for modeling and controlling two serial link manipulators which mutually lift and transport a rigid body object in a three dimensional workspace. A new vector variable is introduced which parameterizes the internal contact force controlled degrees of freedom. A technique for dynamically distributing the payload between the manipulators is suggested which yields a family of solutions for the contact forces and torques the manipulators impart to the object. A set of rigid body kinematic constraints which restrict the values of the joint velocities of both manipulators is derived. A rigid body dynamical model for the closed chain system is first developed in the joint space. The model is obtained by generalizing the previous methods for deriving the model. The joint velocity and acceleration variables in the model are expressed in terms of independent pseudovariables. The pseudospace model is transformed to obtain reduced order equations of motion and a separate set of equations governing the internal components of the contact forces and torques. A theoretic control architecture is suggested which explicitly decouples the two sets of equations comprising the model. The controller enables the designer to develop independent, non-interacting control laws for the position control and internal force control of the system.

  18. Representation of solutions to the problem of the motion of a heavy rigid body in the Kovalevskaya case in terms of Weierstrass \\zeta- and \\wp-functions and nonintegrability of the Hess case by quadratures

    NASA Astrophysics Data System (ADS)

    Belyaev, A. V.

    2016-07-01

    A method for the representation of Delaunay's solutions and some other particular solutions to the problem of the motion of a heavy rigid body in the Kovalevskaya case in terms of the Weierstrass \\zeta- and \\wp-functions is put forward. The Hess case in the problem of the motion of a heavy rigid body is shown to be nonintegrable by quadratures. Bibliography: 24 titles.

  19. Comparison of Efficency of Translation Between a Deformable Swimmer Versus a Rigid Body in a Bounded Fluid Domain: Consequences for Subcellular Transport

    PubMed Central

    González-García, José S.

    2006-01-01

    In this paper, we compare the translation efficiencies of a deformable circle that swims by means of low amplitude periodic tangential surface waves versus a rigid circle, moving in a bounded fluid domain. The swimmer is found to be much more efficient than the rigid body. We believe that this result gives some support to the active hypothesis of subcellular transport, where it is supposed that the organelle can generate by itself a propulsive flux, (by changes of form or metabolic activities) instead of just being carried by the motion of an external agent, like a molecular motor. PMID:19669454

  20. Periodic Motions around the Collinear Equilibrium Points of the R3BP Where the Primary Is a Triaxial Rigid Body and the Secondary Is an Oblate Spheroid

    NASA Astrophysics Data System (ADS)

    Singh, Jagadish; Kalantonis, V. S.; Mrumun Gyegwe, Jessica; Perdiou, A. E.

    2016-12-01

    We consider a modification of the restricted three-body problem where the primary (more massive body) is a triaxial rigid body and the secondary (less massive body) is an oblate spheroid and study periodic motions around the collinear equilibrium points. The locations of these points are first determined for 10 combinations of the parameters of the problem. In all 10 cases, the collinear equilibrium points are found to be unstable, as in the classical problem, and the Lyapunov periodic orbits around them have been computed accurately by applying known corrector-predictor algorithms. An extensive study on the families of three-dimensional periodic orbits emanating from these points has also been done. To find suitable starting points, for all the computed families, semianalytical solutions have been obtained, for both two- and three-dimensional cases, around the collinear equilibrium points using the Lindstedt-Poincaré method. Finally, the stability of all computed periodic orbits has been studied.

  1. Experiences in determination of non-rigid body motion in industrial environment using low-cost photogrammetry

    NASA Astrophysics Data System (ADS)

    Rupnik, Ewelina; Jansa, Josef

    2013-04-01

    Central to our investigation is determination of dynamic behaviour of a highly reflective platform floating on water, as well as derivation of parameters defining instantaneous water state. The employed imaging setup consists of three off-the-shelf dSLR cameras capable of video recording at a 30Hz frame rate. In order to observe a change, the non-rigid and non-diffuse bodies impose the adoption of artificial targetting and custom measurement algorithms. Attention will be given to an in-house software tool implemented to carry out point measurement, correspondence search, tracking and outlier detection methods in the presence of specular reflections and a multimedia scene. A methodology for retrieval of wave parameters in regular wave conditions is also automatically handled by the software and will be discussed. In the context of performed measurements and achieved results, we will point out the extent to which consumer grade camera can fulfil automation and accuracy demands of industrial applications and the pitfalls entailed. Lastly, we will elaborate on visual representation of computed motion and deformations.

  2. Improved Accuracy in RNA-Protein Rigid Body Docking by Incorporating Force Field for Molecular Dynamics Simulation into the Scoring Function.

    PubMed

    Iwakiri, Junichi; Hamada, Michiaki; Asai, Kiyoshi; Kameda, Tomoshi

    2016-09-13

    RNA-protein interactions play fundamental roles in many biological processes. To understand these interactions, it is necessary to know the three-dimensional structures of RNA-protein complexes. However, determining the tertiary structure of these complexes is often difficult, suggesting that an accurate rigid body docking for RNA-protein complexes is needed. In general, the rigid body docking process is divided into two steps: generating candidate structures from the individual RNA and protein structures and then narrowing down the candidates. In this study, we focus on the former problem to improve the prediction accuracy in RNA-protein docking. Our method is based on the integration of physicochemical information about RNA into ZDOCK, which is known as one of the most successful computer programs for protein-protein docking. Because recent studies showed the current force field for molecular dynamics simulation of protein and nucleic acids is quite accurate, we modeled the physicochemical information about RNA by force fields such as AMBER and CHARMM. A comprehensive benchmark of RNA-protein docking, using three recently developed data sets, reveals the remarkable prediction accuracy of the proposed method compared with existing programs for docking: the highest success rate is 34.7% for the predicted structure of the RNA-protein complex with the best score and 79.2% for 3,600 predicted ones. Three full atomistic force fields for RNA (AMBER94, AMBER99, and CHARMM22) produced almost the same accurate result, which showed current force fields for nucleic acids are quite accurate. In addition, we found that the electrostatic interaction and the representation of shape complementary between protein and RNA plays the important roles for accurate prediction of the native structures of RNA-protein complexes.

  3. Defining the limits and reliability of rigid-body fitting in cryo-EM maps using multi-scale image pyramids.

    PubMed

    van Zundert, G C P; Bonvin, A M J J

    2016-08-01

    Cryo-electron microscopy provides fascinating structural insight into large macromolecular machines at increasing detail. Despite significant advances in the field, the resolution of the resulting three-dimensional images is still typically insufficient for de novo model building. To bridge the resolution gap and give an atomic interpretation to the data, high-resolution models are typically placed into the density as rigid bodies. Unfortunately, this is often done manually using graphics software, a subjective method that can lead to over-interpretation of the data. A more objective approach is to perform an exhaustive cross-correlation-based search to fit subunits into the density. Here we show, using five experimental ribosome maps ranging in resolution from 5.5 to 6.9Å, that cross-correlation-based fitting is capable of successfully fitting subunits correctly in the density for over 90% of the cases. Importantly, we provide indicators for the reliability and ambiguity of a fit, using the Fisher z-transformation and its associated confidence intervals, giving a formal approach to identify over-interpreted regions in the density. In addition, we quantify the resolution requirement for a successful fit as a function of the subunit size. For larger subunits the resolution of the data can be down-filtered to 20Å while still retaining an unambiguous fit. We leverage this information through the use of multi-scale image pyramids to accelerate the search up to 30-fold on CPUs and 40-fold on GPUs at a negligible loss in success rate. We implemented this approach in our rigid-body fitting software PowerFit, which can be freely downloaded from https://github.com/haddocking/powerfit.

  4. Multiple zone coal degasification potential in the Warrior coal field of Alabama

    SciTech Connect

    Graves, S.L.; Patton, A.F.; Beavers, W.M.

    1983-01-01

    The upper Pottsville Formation in the Warrior coal field of Alabama has 7 recognized groups of bituminous coal seams. Three of these groups, the Pratt, Mary Lee, and Black Creek, consist of seams containing commercially significant quantities of methane. Each group has several seams within a vertical interval that, in many areas, can be collectively stimulated. In parts of the Warrior coal field, where all 3 groups can be penetrated in one vertical borehole, the potential production from multiple zone completion wells can result in commercially profitable wells. Various open hole and through-the-casing completion procedures are being applied, resulting in successful methane production from these multiple-zone-coal-gas wells.

  5. Multiple zone coal degasification potential in Warrior coal field of Alabama

    SciTech Connect

    Graves, S.L.; Patton, A.F.; Beavers, W.M.

    1983-09-01

    The upper Pottsville Formation in the Warrior coal field of Alabama has seven recognized groups of bituminous coal seams. Three of these groups, the Pratt, Mary Lee, and Black Creek, consist of seams containing commercially significant quantities of methane. Each group has several seams within a vertical interval that, in many areas, can be stimulated collectively. In parts of the Warrior coal field, where all three groups can be penetrated in one vertical borehole, the potential production from multiple zone completion wells can result in commerically profitable wells. Various open-hole and through-the-casing completion procedures are being applied, resulting in successful methane production from these multiple zone coal gas wells.

  6. Non-linear dynamic analyses of 3D masonry structures by means of a homogenized rigid body and spring model (HRBSM)

    NASA Astrophysics Data System (ADS)

    Bertolesi, Elisa; Milani, Gabriele; Casolo, Siro

    2016-12-01

    A simple homogenized rigid body and spring model (HRBSM) is presented and applied for the non-linear dynamic analysis of 3D masonry structures. The approach, previously developed by the authors for the modeling of in-plane loaded walls is herein extended to real 3D buildings subjected to in- and out-of-plane deformation modes. The elementary cell is discretized by means of three-noded plane stress elements and non-linear interfaces. At a structural level, the non-linear analyses are performed replacing the homogenized orthotropic continuum with a rigid element and non-linear spring assemblage (RBSM) by means of which both in and out of plane mechanisms are allowed. All the simulations here presented are performed using the commercial software Abaqus. In order to validate the proposed model for the analyses of full scale structures subjected to seismic actions, two different examples are critically discussed, namely a church façade and an in-scale masonry building, both subjected to dynamic excitation. The results obtained are compared with experimental or numerical results available in literature.

  7. A study on a rigid body boundary layer interface force model for stress calculation and stress strain behaviour of nanoscale uniaxial tension

    NASA Astrophysics Data System (ADS)

    Lin, Zone-Ching; Huang, Jen-Ching

    2004-11-01

    A rigid body boundary layer interface force (RIF) model for stress calculation on the nanoscale is proposed in this paper for calculating stress based on molecular dynamics. The RIF model is used to study the stress-stain behaviour when nanoscale single crystal copper is under uniaxial tension, and is used for 15 tensile simulations each with different strain rate. The stress-strain curve established from simulation was first converted into a true stress-strain curve; a regression analysis was then applied in order to find the flow curve. From simulation results, it is found that the strain rate has large influence on both K and n values of the flow curve. At low strain rate (less than 1 × 1012 s-1), both K and n values decrease with the increase of strain rate. When the strain rate exceeds 1 × 1012 s-1, the strain rate against the K and n values of the flow curve approaches a constant. Flow curve equations considering the influence of strain rate are derived; both complete and simplified forms of flow curve equations are also derived. It is observed that the lower the strain rates, the higher the fluctuations of the stress-strain curve. Furthermore, the increase of strain rate resulting in a smoother stress-strain curve is also found.

  8. Real-Time Correction of Rigid-Body-Motion-Induced Phase Errors for Diffusion-Weighted Steady State Free Precession Imaging

    PubMed Central

    O’Halloran, R; Aksoy, M; Aboussouan, E; Peterson, E; Van, A; Bammer, R

    2014-01-01

    Purpose Diffusion contrast in diffusion-weighted steady state free precession MRI is generated through the constructive addition of signal from many coherence pathways. Motion-induced phase causes destructive interference which results in loss of signal magnitude and diffusion contrast. In this work, a 3D navigator-based real-time correction of the rigid-body-motion-induced phase errors is developed for diffusion-weighted steady state free precession MRI. Methods The efficacy of the real-time prospective correction method in preserving phase coherence of the steady-state is tested in 3D phantom experiments and 3D scans of healthy human subjects. Results In nearly all experiments, the signal magnitude in images obtained with proposed prospective correction was higher than the signal magnitude in images obtained with no correction. In the human subjects the mean magnitude signal in the data was up to 30 percent higher with prospective motion correction than without. Prospective correction never resulted in a decrease in mean signal magnitude in either the data or in the images. Conclusions The proposed prospective motion correction method is shown to preserve the phase coherence of the steady state in diffusion-weighted steady state free precession MRI, thus mitigating signal magnitude losses that would confound the desired diffusion contrast. PMID:24715414

  9. A 3D, fully Eulerian, VOF-based solver to study the interaction between two fluids and moving rigid bodies using the fictitious domain method

    NASA Astrophysics Data System (ADS)

    Pathak, Ashish; Raessi, Mehdi

    2016-04-01

    We present a three-dimensional (3D) and fully Eulerian approach to capturing the interaction between two fluids and moving rigid structures by using the fictitious domain and volume-of-fluid (VOF) methods. The solid bodies can have arbitrarily complex geometry and can pierce the fluid-fluid interface, forming contact lines. The three-phase interfaces are resolved and reconstructed by using a VOF-based methodology. Then, a consistent scheme is employed for transporting mass and momentum, allowing for simulations of three-phase flows of large density ratios. The Eulerian approach significantly simplifies numerical resolution of the kinematics of rigid bodies of complex geometry and with six degrees of freedom. The fluid-structure interaction (FSI) is computed using the fictitious domain method. The methodology was developed in a message passing interface (MPI) parallel framework accelerated with graphics processing units (GPUs). The computationally intensive solution of the pressure Poisson equation is ported to GPUs, while the remaining calculations are performed on CPUs. The performance and accuracy of the methodology are assessed using an array of test cases, focusing individually on the flow solver and the FSI in surface-piercing configurations. Finally, an application of the proposed methodology in simulations of the ocean wave energy converters is presented.

  10. Improvement of registration accuracy in accelerated partial breast irradiation using the point-based rigid-body registration algorithm for patients with implanted fiducial markers

    SciTech Connect

    Inoue, Minoru; Yoshimura, Michio Sato, Sayaka; Nakamura, Mitsuhiro; Yamada, Masahiro; Hirata, Kimiko; Ogura, Masakazu; Hiraoka, Masahiro; Sasaki, Makoto; Fujimoto, Takahiro

    2015-04-15

    Purpose: To investigate image-registration errors when using fiducial markers with a manual method and the point-based rigid-body registration (PRBR) algorithm in accelerated partial breast irradiation (APBI) patients, with accompanying fiducial deviations. Methods: Twenty-two consecutive patients were enrolled in a prospective trial examining 10-fraction APBI. Titanium clips were implanted intraoperatively around the seroma in all patients. For image-registration, the positions of the clips in daily kV x-ray images were matched to those in the planning digitally reconstructed radiographs. Fiducial and gravity registration errors (FREs and GREs, respectively), representing resulting misalignments of the edge and center of the target, respectively, were compared between the manual and algorithm-based methods. Results: In total, 218 fractions were evaluated. Although the mean FRE/GRE values for the manual and algorithm-based methods were within 3 mm (2.3/1.7 and 1.3/0.4 mm, respectively), the percentages of fractions where FRE/GRE exceeded 3 mm using the manual and algorithm-based methods were 18.8%/7.3% and 0%/0%, respectively. Manual registration resulted in 18.6% of patients with fractions of FRE/GRE exceeding 5 mm. The patients with larger clip deviation had significantly more fractions showing large FRE/GRE using manual registration. Conclusions: For image-registration using fiducial markers in APBI, the manual registration results in more fractions with considerable registration error due to loss of fiducial objectivity resulting from their deviation. The authors recommend the PRBR algorithm as a safe and effective strategy for accurate, image-guided registration and PTV margin reduction.

  11. Biquaternion solution of the kinematic control problem for the motion of a rigid body and its application to the solution of inverse problems of robot-manipulator kinematics

    NASA Astrophysics Data System (ADS)

    Chelnokov, Yu. N.

    2013-01-01

    The problem of reducing the body-attached coordinate system to the reference (programmed) coordinate system moving relative to the fixed coordinate system with a given instantaneous velocity screw along a given trajectory is considered in the kinematic statement. The biquaternion kinematic equations of motion of a rigid body in normalized and unnormalized finite displacement biquaternions are used as the mathematical model of motion, and the dual orthogonal projections of the instantaneous velocity screw of the body motion onto the body coordinate axes are used as the control. Various types of correction (stabilization), which are biquaternion analogs of position and integral corrections, are proposed. It is shown that the linear (obtained without linearization) and stationary biquaternion error equations that are invariant under any chosen programmed motion of the reference coordinate system can be obtained for the proposed types of correction and the use of unnormalized finite displacement biquaternions and four-dimensional dual controls allows one to construct globally regular control laws. The general solution of the error equation is constructed, and conditions for asymptotic stability of the programmed motion are obtained. The constructed theory of kinematic control of motion is used to solve inverse problems of robot-manipulator kinematics. The control problem under study is a generalization of the kinematic problem [1, 2] of reducing the body-attached coordinate system to the reference coordinate system rotating at a given (programmed) absolute angular velocity, and the presentedmethod for solving inverse problems of robotmanipulator kinematics is a development of the method proposed in [3-5].

  12. A review of a method for dynamic load distribution, dynamic modeling, and explicit internal force control when two serial link manipulators mutually lift and transport a rigid body object

    SciTech Connect

    Unseren, M.A.

    1997-09-01

    The report reviews a method for modeling and controlling two serial link manipulators which mutually lift and transport a rigid body object in a three dimensional workspace. A new vector variable is introduced which parameterizes the internal contact force controlled degrees of freedom. A technique for dynamically distributing the payload between the manipulators is suggested which yields a family of solutions for the contact forces and torques the manipulators impart to the object. A set of rigid body kinematic constraints which restricts the values of the joint velocities of both manipulators is derived. A rigid body dynamical model for the closed chain system is first developed in the joint space. The model is obtained by generalizing the previous methods for deriving the model. The joint velocity and acceleration variables in the model are expressed in terms of independent pseudovariables. The pseudospace model is transformed to obtain reduced order equations of motion and a separate set of equations governing the internal components of the contact forces and torques. A theoretic control architecture is suggested which explicitly decouples the two sets of equations comprising the model. The controller enables the designer to develop independent, non-interacting control laws for the position control and internal force control of the system.

  13. Research on the automatic laser navigation system of the tunnel boring machine

    NASA Astrophysics Data System (ADS)

    Liu, Yake; Li, Yueqiang

    2011-12-01

    By establishing relevant coordinates of the Automatic Laser Navigation System, the basic principle of the system which accesses the TBM three-dimensional reference point and yawing angle by mathematical transformation between TBM, target prism and earth coordinate systems is discussed deeply in details. According to the way of rigid body descriptions of its posture, TBM attitude parameters measurement and data acquisition methods are proposed, and measures to improve the accuracy of the Laser Navigation System are summarized.

  14. Reversal of left ventricular “rigid body rotation” during dipyridamole-induced stress in a patient with stable angina: a case from the three-dimensional speckle tracking echocardiographic MAGYAR-Stress Study

    PubMed Central

    Szántó, Gyula; Kalapos, Anita; Domsik, Péter; Forster, Tamás

    2016-01-01

    The left ventricular (LV) twist is defined as the wringing motion of the heart around its long-axis in systole caused by oppositely directed counterclockwise apical and clockwise basal rotations resulted from the movement of two orthogonally oriented muscular bands. In some clinical circumstances, rotation at both basal and apical levels of the LV occurred in the same clockwise or counterclockwise direction during systole resulting the near absence of LV twist as called left ventricular “rigid body rotation” (LV-RBR). Hereby we present that LV-RBR normalization of LV rotational mechanics could be demonstrated at maximum hyperaemia during dipyridamole-induced stress by three-dimensional (3D) speckle tracking echocardiography in a patient with stable angina. PMID:27429914

  15. Optimization of an installation angle of a root-cutting blade for an automatic spinach harvester

    NASA Astrophysics Data System (ADS)

    Fujisawa, A.; Chida, Y.

    2016-09-01

    This paper presents an optimization of the installation angle of a root-cutting blade relative to the arm of an automatic spinach harvester. In the harvesting operation, the blade, which is a rigid body, moves under the planted rows in soil of powder consistency to cut the roots of the spinach and to harvest the spinach on a conveyor. Therefore, the interaction between a rigid body and powder is an important consideration. Experiments were conducted on the design of the harvester. The experiments revealed that a certain path of the blade is more favorable for both harvesting spinach easily and minimizing the amount of soil removed by the blade. In this paper, without revising the favorable path, the optimum installation angle of the blade is derived. To derive the installation angle, a nonlinear optimization problem is solved as an evaluation function consisting of the volume of soil pushed by the blade and the installation angle, which is a design parameter. The utility of the installation angle is confirmed by the Discrete Element Method (DEM), which analyzes the interaction between a rigid body and powder.

  16. Left ventricular rigid body rotation in a diffuse large B-cell lymphoma patient with cardiac involvement: A case from the three-dimensional speckle-tracking echocardiographic MAGYAR-Path Study.

    PubMed

    Földeák, Dóra; Kalapos, Anita; Domsik, Péter; Sinkó, Mária; Szeleczki, Nóra; Bagdi, Enikő; Krenács, László; Forster, Tamás; Borbényi, Zita; Nemes, Attila

    2017-02-01

    Secondary myocardial involvement by diffuse large B-cell lymphoma is a rare occurrence. Left ventricular (LV) twist is considered an essential part of LV function. In normal circumstances LV twist results from the movement of two orthogonally oriented muscular bands of a helical myocardial structure with consequent clockwise rotation of the base and counterclockwise rotation of the apex. Three-dimensional (3D) speckle-tracking echocardiography (3DSTE) has been found to be feasible for non-invasive 3D quantification of LV wall motion and rotational mechanics. The present report aimed to assess LV twisting motion in a patient with diffuse large B-cell lymphoma with positron emission tomography/computer tomography-proven cardiac involvement by 3DSTE. During 3DSTE, reduction in some segmental radial, longitudinal, circumferential, area and 3D LV strains were found. Apical and basal LV rotations were found to be in the same counterclockwise direction, confirming near absence of LV twist - so-called rigid body rotation.

  17. Rigid Body Rate Inference from Attitude Variation

    NASA Technical Reports Server (NTRS)

    Bar-Itzhack, I. Y.; Harman, Richard R.; Thienel, Julie K.

    2006-01-01

    In this paper we research the extraction of the angular rate vector from attitude information without differentiation, in particular from quaternion measurements. We show that instead of using a Kalman filter of some kind, it is possible to obtain good rate estimates, suitable for spacecraft attitude control loop damping, using simple feedback loops, thereby eliminating the need for recurrent covariance computation performed when a Kalman filter is used. This considerably simplifies the computations required for rate estimation in gyro-less spacecraft. Some interesting qualities of the Kalman filter gain are explored, proven and utilized. We examine two kinds of feedback loops, one with varying gain that is proportional to the well known Q matrix, which is computed using the measured quaternion, and the other type of feedback loop is one with constant coefficients. The latter type includes two kinds; namely, a proportional feedback loop, and a proportional-integral feedback loop. The various schemes are examined through simulations and their performance is compared. It is shown that all schemes are adequate for extracting the angular velocity at an accuracy suitable for control loop damping.

  18. Rigid body constrained noisy point pattern matching.

    PubMed

    Morgera, S D; Cheong, P C

    1995-01-01

    Noisy pattern matching problems arise in many areas, e.g., computational vision, robotics, guidance and control, stereophotogrammetry, astronomy, genetics, and high-energy physics. Least-squares pattern matching over the Euclidean space E(n) for unordered sets of cardinalities p and q is commonly formulated as a combinatorial optimization problem having complexity p(p-1)...(p-q+1), q=/

  19. Thin structured rigid body for acoustic absorption

    NASA Astrophysics Data System (ADS)

    Starkey, T. A.; Smith, J. D.; Hibbins, A. P.; Sambles, J. R.; Rance, H. J.

    2017-01-01

    We present a thin acoustic metamaterial absorber, comprised of only rigid metal and air, that gives rise to near unity absorption of airborne sound on resonance. This simple, easily fabricated, robust structure comprising a perforated metal plate separated from a rigid wall by a deeply subwavelength channel of air is an ideal candidate for a sound absorbing panel. The strong absorption in the system is attributed to the thermo-viscous losses arising from a sound wave guided between the plate and the wall, defining the subwavelength channel.

  20. Motion Planning for Rigid Body Robots

    DTIC Science & Technology

    1992-06-01

    Given a non-holonomic disc robot D, its motion constraints in terms of maximum curvature (Kmax) and rate of change of curvature (Kmax), a set W of...further Kmax, constraint to avoid turns that exceed the rate of change of curvature constraint.

  1. Automatic Imitation

    ERIC Educational Resources Information Center

    Heyes, Cecilia

    2011-01-01

    "Automatic imitation" is a type of stimulus-response compatibility effect in which the topographical features of task-irrelevant action stimuli facilitate similar, and interfere with dissimilar, responses. This article reviews behavioral, neurophysiological, and neuroimaging research on automatic imitation, asking in what sense it is "automatic"…

  2. Flow Rates Measurement and Uncertainty Analysis in Multiple-Zone Water-Injection Wells from Fluid Temperature Profiles

    PubMed Central

    Reges, José E. O.; Salazar, A. O.; Maitelli, Carla W. S. P.; Carvalho, Lucas G.; Britto, Ursula J. B.

    2016-01-01

    This work is a contribution to the development of flow sensors in the oil and gas industry. It presents a methodology to measure the flow rates into multiple-zone water-injection wells from fluid temperature profiles and estimate the measurement uncertainty. First, a method to iteratively calculate the zonal flow rates using the Ramey (exponential) model was described. Next, this model was linearized to perform an uncertainty analysis. Then, a computer program to calculate the injected flow rates from experimental temperature profiles was developed. In the experimental part, a fluid temperature profile from a dual-zone water-injection well located in the Northeast Brazilian region was collected. Thus, calculated and measured flow rates were compared. The results proved that linearization error is negligible for practical purposes and the relative uncertainty increases as the flow rate decreases. The calculated values from both the Ramey and linear models were very close to the measured flow rates, presenting a difference of only 4.58 m³/d and 2.38 m³/d, respectively. Finally, the measurement uncertainties from the Ramey and linear models were equal to 1.22% and 1.40% (for injection zone 1); 10.47% and 9.88% (for injection zone 2). Therefore, the methodology was successfully validated and all objectives of this work were achieved. PMID:27420068

  3. Automatic transmission

    SciTech Connect

    Miura, M.; Aoki, H.

    1988-02-02

    An automatic transmission is described comprising: an automatic transmission mechanism portion comprising a single planetary gear unit and a dual planetary gear unit; carriers of both of the planetary gear units that are integral with one another; an input means for inputting torque to the automatic transmission mechanism, clutches for operatively connecting predetermined ones of planetary gear elements of both of the planetary gear units to the input means and braking means for restricting the rotation of predetermined ones of planetary gear elements of both of the planetary gear units. The clutches are disposed adjacent one another at an end portion of the transmission for defining a clutch portion of the transmission; a first clutch portion which is attachable to the automatic transmission mechanism portion for comprising the clutch portion when attached thereto; a second clutch portion that is attachable to the automatic transmission mechanism portion in place of the first clutch portion for comprising the clutch portion when so attached. The first clutch portion comprising first clutch for operatively connecting the input means to a ring gear of the single planetary gear unit and a second clutch for operatively connecting the input means to a single gear of the automatic transmission mechanism portion. The second clutch portion comprising a the first clutch, the second clutch, and a third clutch for operatively connecting the input member to a ring gear of the dual planetary gear unit.

  4. Automatic registration of serial mammary gland sections

    SciTech Connect

    Arganda-Carreras, Ignacio; Fernandez-Gonzalez, Rodrigo; Ortiz-de-Solorzano, Carlos

    2004-04-13

    We present two new methods for automatic registration of microscope images of consecutive tissue sections. They represent two possibilities for the first step in the 3-D reconstruction of histological structures from serially sectioned tissue blocks. The goal is to accurately align the sections in order to place every relevant shape contained in each image in front of its corresponding shape in the following section before detecting the structures of interest and rendering them in 3D. This is accomplished by finding the best rigid body transformation (translation and rotation) of the image being registered by maximizing a matching function based on the image content correlation. The first method makes use of the entire image information, whereas the second one uses only the information located at specific sites, as determined by the segmentation of the most relevant tissue structures. To reduce computing time, we use a multiresolution pyramidal approach that reaches the best registration transformation in increasing resolution steps. In each step, a subsampled version of the images is used. Both methods rely on a binary image which is a thresholded version of the Sobel gradients of the image (first method) or a set of boundaries manually or automatically obtained that define important histological structures of the sections. Then distance-transform of the binary image is computed. A proximity function is then calculated between the distance image of the image being registered and that of the reference image. The transformation providing a maximum of the proximity function is then used as the starting point of the following step. This is iterated until the registration error lies below a minimum value.

  5. AUTOMATIC COUNTER

    DOEpatents

    Robinson, H.P.

    1960-06-01

    An automatic counter of alpha particle tracks recorded by a sensitive emulsion of a photographic plate is described. The counter includes a source of mcdulated dark-field illumination for developing light flashes from the recorded particle tracks as the photographic plate is automatically scanned in narrow strips. Photoelectric means convert the light flashes to proportional current pulses for application to an electronic counting circuit. Photoelectric means are further provided for developing a phase reference signal from the photographic plate in such a manner that signals arising from particle tracks not parallel to the edge of the plate are out of phase with the reference signal. The counting circuit includes provision for rejecting the out-of-phase signals resulting from unoriented tracks as well as signals resulting from spurious marks on the plate such as scratches, dust or grain clumpings, etc. The output of the circuit is hence indicative only of the tracks that would be counted by a human operator.

  6. Automatic transmission

    SciTech Connect

    Ohkubo, M.

    1988-02-16

    An automatic transmission is described combining a stator reversing type torque converter and speed changer having first and second sun gears comprising: (a) a planetary gear train composed of first and second planetary gears sharing one planetary carrier in common; (b) a clutch and requisite brakes to control the planetary gear train; and (c) a speed-increasing or speed-decreasing mechanism is installed both in between a turbine shaft coupled to a turbine of the stator reversing type torque converter and the first sun gear of the speed changer, and in between a stator shaft coupled to a reversing stator and the second sun gear of the speed changer.

  7. Automatic transmission

    SciTech Connect

    Miki, N.

    1988-10-11

    This patent describes an automatic transmission including a fluid torque converter, a first gear unit having three forward-speed gears and a single reverse gear, a second gear unit having a low-speed gear and a high-speed gear, and a hydraulic control system, the hydraulic control system comprising: a source of pressurized fluid; a first shift valve for controlling the shifting between the first-speed gear and the second-speed gear of the first gear unit; a second shift valve for controlling the shifting between the second-speed gear and the third-speed gear of the first gear unit; a third shift valve equipped with a spool having two positions for controlling the shifting between the low-speed gear and the high-speed gear of the second gear unit; a manual selector valve having a plurality of shift positions for distributing the pressurized fluid supply from the source of pressurized fluid to the first, second and third shift valves respectively; first, second and third solenoid valves corresponding to the first, second and third shift valves, respectively for independently controlling the operation of the respective shift valves, thereby establishing a six forward-speed automatic transmission by combining the low-speed gear and the high-speed gear of the second gear unit with each of the first-speed gear, the second speed gear and the third-speed gear of the first gear unit; and means to fixedly position the spool of the third shift valve at one of the two positions by supplying the pressurized fluid to the third shift valve when the manual selector valve is shifted to a particular shift position, thereby locking the second gear unit in one of low-speed gear and the high-speed gear, whereby the six forward-speed automatic transmission is converted to a three forward-speed automatic transmission when the manual selector valve is shifted to the particular shift position.

  8. Automatic transmission

    SciTech Connect

    Aoki, H.

    1989-03-21

    An automatic transmission is described, comprising: a torque converter including an impeller having a connected member, a turbine having an input member and a reactor; and an automatic transmission mechanism having first to third clutches and plural gear units including a single planetary gear unit with a ring gear and a dual planetary gear unit with a ring gear. The single and dual planetary gear units have respective carriers integrally coupled with each other and respective sun gears integrally coupled with each other, the input member of the turbine being coupled with the ring gear of the single planetary gear unit through the first clutch, and being coupled with the sun gear through the second clutch. The connected member of the impeller is coupled with the ring gear of the dual planetary gear of the dual planetary gear unit is made to be and ring gear of the dual planetary gear unit is made to be restrained as required, and the carrier is coupled with an output member.

  9. Automatic transmission

    SciTech Connect

    Hamane, M.; Ohri, H.

    1989-03-21

    This patent describes an automatic transmission connected between a drive shaft and a driven shaft and comprising: a planetary gear mechanism including a first gear driven by the drive shaft, a second gear operatively engaged with the first gear to transmit speed change output to the driven shaft, and a third gear operatively engaged with the second gear to control the operation thereof; centrifugally operated clutch means for driving the first gear and the second gear. It also includes a ratchet type one-way clutch for permitting rotation of the third gear in the same direction as that of the drive shaft but preventing rotation in the reverse direction; the clutch means comprising a ratchet pawl supporting plate coaxially disposed relative to the drive shaft and integrally connected to the third gear, the ratchet pawl supporting plate including outwardly projection radial projections united with one another at base portions thereof.

  10. Automatic transmission

    SciTech Connect

    Meyman, U.

    1987-03-10

    An automatic transmission is described comprising wheel members each having discs defining an inner space therebetween; turnable blades and vane members located in the inner space between the discs of at least one of the wheel members, the turnable blades being mechanically connected with the vane members. Each of the turnable blades has an inner surface and an outer surface formed by circular cylindrical surfaces having a common axis, each of the turnable blades being turnable about the common axis of the circular cylindrical surfaces forming the inner and outer surfaces of the respective blade; levers turnable about the axes and supporting the blades; the discs having openings extending coaxially with the surfaces which describe the blades. The blades are partially received in the openings of the discs; and a housing accommodating the wheel members and the turnable blades and the vane members.

  11. Automatic transmission

    SciTech Connect

    Miura, M.; Inuzuka, T.

    1986-08-26

    1. An automatic transmission with four forward speeds and one reverse position, is described which consists of: an input shaft; an output member; first and second planetary gear sets each having a sun gear, a ring gear and a carrier supporting a pinion in mesh with the sun gear and ring gear; the carrier of the first gear set, the ring gear of the second gear set and the output member all being connected; the ring gear of the first gear set connected to the carrier of the second gear set; a first clutch means for selectively connecting the input shaft to the sun gear of the first gear set, including friction elements, a piston selectively engaging the friction elements and a fluid servo in which hydraulic fluid is selectively supplied to the piston; a second clutch means for selectively connecting the input shaft to the sun gear of the second gear set a third clutch means for selectively connecting the input shaft to the carrier of the second gear set including friction elements, a piston selectively engaging the friction elements and a fluid servo in which hydraulic fluid is selectively supplied to the piston; a first drive-establishing means for selectively preventing rotation of the ring gear of the first gear set and the carrier of the second gear set in only one direction and, alternatively, in any direction; a second drive-establishing means for selectively preventing rotation of the sun gear of the second gear set; and a drum being open to the first planetary gear set, with a cylindrical intermediate wall, an inner peripheral wall and outer peripheral wall and forming the hydraulic servos of the first and third clutch means between the intermediate wall and the inner peripheral wall and between the intermediate wall and the outer peripheral wall respectively.

  12. Automatic transmission adapter kit

    SciTech Connect

    Stich, R.L.; Neal, W.D.

    1987-02-10

    This patent describes, in a four-wheel-drive vehicle apparatus having a power train including an automatic transmission and a transfer case, an automatic transmission adapter kit for installation of a replacement automatic transmission of shorter length than an original automatic transmission in the four-wheel-drive vehicle. The adapter kit comprises: an extension housing interposed between the replacement automatic transmission and the transfer case; an output shaft, having a first end which engages the replacement automatic transmission and a second end which engages the transfer case; first sealing means for sealing between the extension housing and the replacement automatic transmission; second sealing means for sealing between the extension housing and the transfer case; and fastening means for connecting the extension housing between the replacement automatic transmission and the transfer case.

  13. Unsteady Transonic Flow Past Airfoils in Rigid Body Motion.

    DTIC Science & Technology

    1981-03-01

    weak solutions. The linear theory is deficient in predicting important features of transonic flow outside airfoils in low reduced frequency motion...terms. The term t is substituted n+l adn -i n n+l +n-i by the mean of and , i.e., = 2 = -(u 2 +2uv y+V 2 $ q2 xx xyq 1 2uF v2-2-5 n+l n-I(v2 + 2uvT + 2 ( I...approximate for thie advection equation. Our approximate factorizatio. says that (2) can .) factored as (1+tuQ 14tv )*N - -. tu )(l-.ltvD ) M - 2.’,t (uP DvD Ki

  14. Efficiency of wave-driven rigid body rotation toroidal confinement

    NASA Astrophysics Data System (ADS)

    Rax, J. M.; Gueroult, R.; Fisch, N. J.

    2017-03-01

    The compensation of vertical drifts in toroidal magnetic fields through a wave-driven poloidal rotation is compared with compensation through the wave driven toroidal current generation to support the classical magnetic rotational transform. The advantages and drawbacks associated with the sustainment of a radial electric field are compared with those associated with the sustainment of a poloidal magnetic field both in terms of energy content and power dissipation. The energy content of a radial electric field is found to be smaller than the energy content of a poloidal magnetic field for a similar set of orbits. The wave driven radial electric field generation efficiency is similarly shown, at least in the limit of large aspect ratio, to be larger than the efficiency of wave-driven toroidal current generation.

  15. Fractional-order theory of heat transport in rigid bodies

    NASA Astrophysics Data System (ADS)

    Zingales, Massimiliano

    2014-11-01

    The non-local model of heat transfer, used to describe the deviations of the temperature field from the well-known prediction of Fourier/Cattaneo models experienced in complex media, is framed in the context of fractional-order calculus. It has been assumed (Borino et al., 2011 [53], Mongioví and Zingales, 2013 [54]) that thermal energy transport is due to two phenomena: (i) A short-range heat flux ruled by a local transport equation; (ii) A long-range thermal energy transfer proportional to a distance-decaying function, to the relative temperature and to the product of the interacting masses. The distance-decaying function is assumed in the functional class of the power-law decay of the distance yielding a novel temperature equation in terms of α-order Marchaud fractional-order derivative (0⩽α⩽1). Thermodynamical consistency of the model is provided in the context of Clausius-Plank inequality. The effects induced by the boundary conditions on the temperature field are investigated for diffusive as well as ballistic local heat flux. Deviations of the temperature field from the linear distributions in the neighborhood of the thermostated zones of small-scale conductors are qualitatively predicted by the used fractional-order heat transport model, as shown by means of molecular dynamics simulations.

  16. Derivation of Rigid Body Analysis Models from Vehicle Architecture Abstractions

    DTIC Science & Technology

    2011-06-17

    simultaneously with the model creation. The author has described the evolution of the car design process from the conventional approach to the new development...models of every type have their basis in some type of physical representation of the design domain. Rather than describing three-dimensional continua of...arrangement, while capturing just enough physical detail to be used as the basis for a meaningful representation of the design , and eventually, analyses that

  17. Validation Study of Two Rigid Body Dynamic Computer Models

    DTIC Science & Technology

    1992-09-01

    equations 2.8 and 2.9 into equation 2.7 yields m(6rT+6•Tgl AT)( f +A• *S’ P +Ar, ) ’W8P) dmn (P) -fm(6rT+6tIr •fPAT) F(P) dmh (P) = 0 (2.10) for all 6r...I a a 0o 2S -- - -i- i ___ V a a I a i a a i 10 ..... 0 ...... .. a... a a 0 * a aa a 00 I0 a5 a0 a 3 measur~ed u piPtch rat . e (d on t/u riersea as

  18. A Digital Computer Approach to the Unsymmetric Rigid Body Problem.

    DTIC Science & Technology

    1982-03-01

    remained an unresolved problem in classical dynamics. The problem can be completely specified mathematically , but in most cases the solution cannot be...solution of particular problems, but lead to important theoretical generalizations in fields such as quantum, statistical , and celestial mechanics...weighted residual method, and the mathematical expressions in the higher iterations 17 AFWAL-TR-81 -1245 become cumbersome. However, foundations are laid

  19. Hamiltonian Dynamics of Spider-Type Multirotor Rigid Bodies Systems

    SciTech Connect

    Doroshin, Anton V.

    2010-03-01

    This paper sets out to develop a spider-type multiple-rotor system which can be used for attitude control of spacecraft. The multirotor system contains a large number of rotor-equipped rays, so it was called a 'Spider-type System', also it can be called 'Rotary Hedgehog'. These systems allow using spinups and captures of conjugate rotors to perform compound attitude motion of spacecraft. The paper describes a new method of spacecraft attitude reorientation and new mathematical model of motion in Hamilton form. Hamiltonian dynamics of the system is investigated with the help of Andoyer-Deprit canonical variables. These variables allow obtaining exact solution for hetero- and homoclinic orbits in phase space of the system motion, which are very important for qualitative analysis.

  20. Robust tracking control of a magnetically suspended rigid body

    NASA Technical Reports Server (NTRS)

    Lim, Kyong B.; Cox, David E.

    1994-01-01

    This study is an application of H-infinity and micro-synthesis for designing robust tracking controllers for the Large Angle Magnetic Suspension Test Facility. The modeling, design, analysis, simulation, and testing of a control law that guarantees tracking performance under external disturbances and model uncertainties is investigated. The type of uncertainties considered and the tracking performance metric used is discussed. This study demonstrates the tradeoff between tracking performance at low frequencies and robustness at high frequencies. Two sets of controllers were designed and tested. The first set emphasized performance over robustness, while the second set traded off performance for robustness. Comparisons of simulation and test results are also included. Current simulation and experimental results indicate that reasonably good robust tracking performance can be attained for this system using multivariable robust control approach.

  1. Fluid-Structure Interactions with Flexible and Rigid Bodies

    NASA Astrophysics Data System (ADS)

    Daily, David Jesse

    Fluid structure interactions occur to some extent in nearly every type of fluid flow. Understanding how structures interact with fluids and visa-versa is of vital importance in many engineering applications. The purpose of this research is to explore how fluids interact with flexible and rigid structures. A computational model was used to model the fluid structure interactions of vibrating synthetic vocal folds. The model simulated the coupling of the fluid and solid domains using a fluid-structure interface boundary condition. The fluid domain used a slightly compressible flow solver to allow for the possibility of acoustic coupling with the subglottal geometry and vibration of the vocal fold model. As the subglottis lengthened, the frequency of vibration decreased until a new acoustic mode could form in the subglottis. Synthetic aperture particle image velocimetry (SAPIV) is a three-dimensional particle tracking technique. SAPIV was used to image the jet of air that emerges from vibrating human vocal folds (glottal jet) during phonation. The three-dimensional reconstruction of the glottal jet found faint evidence of flow characteristics seen in previous research, such as axis-switching, but did not have sufficient resolution to detect small features. SAPIV was further applied to reconstruct the smaller flow characteristics of the glottal jet of vibrating synthetic vocal folds. Two- and four-layer synthetic vocal fold models were used to determine how the glottal jet from the synthetic models compared to the glottal jet from excised human vocal folds. The two- and four-layer models clearly exhibited axis-switching which has been seen in other 3D analyses of the glottal jet. Cavitation in a quiescent fluid can break a rigid structure such as a glass bottle. A new cavitation number was derived to include acceleration and pressure head at cavitation onset. A cavitation stick was used to validate the cavitation number by filling it with different depths and hitting the stick to cause fluid cavitation. Acceleration was measured using an accelerometer and cavitation bubbles were detected using a high-speed camera. Cavitation in an accelerating fluid occurred at a cavitation number of 1. Keywords: Fluid structure interaction, vocal folds, acoustics, SAPIV, cavitation, slightly compressible

  2. Rigid body dynamics in non-Euclidean spaces

    NASA Astrophysics Data System (ADS)

    Borisov, A. V.; Mamaev, I. S.

    2016-10-01

    In this paper, we focus on the study of two-dimensional plate dynamics on the Lobachevskii plane L 2. First of all, we consider the free motion of such a plate, which is a pseudospherical analog of dynamics of the Euler top, and also present an analog of the Euler-Poisson equations enabling us to study the motion of the body in potential force fields having rotational symmetry. We present a series of integrable cases, having analogs in Euclidean space, for different fields. Moreover, in the paper, a partial qualitative analysis of the dynamics of free motion of a plate under arbitrary initial conditions is made and a number of computer illustrations are presented which show a substantial difference of the motion from the case of Euclidean space. The study undertaken in the present paper leads to interesting physical consequences, which enable us to detect the influence of curvature on the body dynamics.

  3. Robust automatic rigid registration of MRI and X-ray using external fiducial markers for XFM-guided interventional procedures

    PubMed Central

    George, Ashvin K.; Sonmez, Merdim; Lederman, Robert J.; Faranesh, Anthony Z.

    2011-01-01

    Purpose: In X-ray fused with MRI, previously gathered roadmap MRI volume images are overlaid on live X-ray fluoroscopy images to help guide the clinician during an interventional procedure. The incorporation of MRI data allows for the visualization of soft tissue that is poorly visualized under X-ray. The widespread clinical use of this technique will require fully automating as many components as possible. While previous use of this method has required time-consuming manual intervention to register the two modalities, in this article, the authors present a fully automatic rigid-body registration method. Methods: External fiducial markers that are visible under these two complimentary imaging modalities were used to register the X-ray images with the roadmap MR images. The method has three components: (a) The identification of the 3D locations of the markers from a full 3D MR volume, (b) the identification of the 3D locations of the markers from a small number of 2D X-ray fluoroscopy images, and (c) finding the rigid-body transformation that registers the two point sets in the two modalities. For part (a), the localization of the markers from MR data, the MR volume image was thresholded, connected voxels were segmented and labeled, and the centroids of the connected components were computed. For part (b), the X-ray projection images, produced by an image intensifier, were first corrected for distortions. Binary mask images of the markers were created from the distortion-corrected X-ray projection images by applying edge detection, pattern recognition, and image morphological operations. The markers were localized in the X-ray frame using an iterative backprojection-based method which segments voxels in the volume of interest, discards false positives based on the previously computed edge-detected projections, and calculates the locations of the true markers as the centroids of the clusters of voxels that remain. For part (c), a variant of the iterative closest

  4. Robust automatic rigid registration of MRI and X-ray using external fiducial markers for XFM-guided interventional procedures

    SciTech Connect

    George, Ashvin K.; Sonmez, Merdim; Lederman, Robert J.; Faranesh, Anthony Z.

    2011-01-15

    Purpose: In X-ray fused with MRI, previously gathered roadmap MRI volume images are overlaid on live X-ray fluoroscopy images to help guide the clinician during an interventional procedure. The incorporation of MRI data allows for the visualization of soft tissue that is poorly visualized under X-ray. The widespread clinical use of this technique will require fully automating as many components as possible. While previous use of this method has required time-consuming manual intervention to register the two modalities, in this article, the authors present a fully automatic rigid-body registration method. Methods: External fiducial markers that are visible under these two complimentary imaging modalities were used to register the X-ray images with the roadmap MR images. The method has three components: (a) The identification of the 3D locations of the markers from a full 3D MR volume, (b) the identification of the 3D locations of the markers from a small number of 2D X-ray fluoroscopy images, and (c) finding the rigid-body transformation that registers the two point sets in the two modalities. For part (a), the localization of the markers from MR data, the MR volume image was thresholded, connected voxels were segmented and labeled, and the centroids of the connected components were computed. For part (b), the X-ray projection images, produced by an image intensifier, were first corrected for distortions. Binary mask images of the markers were created from the distortion-corrected X-ray projection images by applying edge detection, pattern recognition, and image morphological operations. The markers were localized in the X-ray frame using an iterative backprojection-based method which segments voxels in the volume of interest, discards false positives based on the previously computed edge-detected projections, and calculates the locations of the true markers as the centroids of the clusters of voxels that remain. For part (c), a variant of the iterative closest

  5. Automatic differentiation bibliography

    SciTech Connect

    Corliss, G.F.

    1992-07-01

    This is a bibliography of work related to automatic differentiation. Automatic differentiation is a technique for the fast, accurate propagation of derivative values using the chain rule. It is neither symbolic nor numeric. Automatic differentiation is a fundamental tool for scientific computation, with applications in optimization, nonlinear equations, nonlinear least squares approximation, stiff ordinary differential equation, partial differential equations, continuation methods, and sensitivity analysis. This report is an updated version of the bibliography which originally appeared in Automatic Differentiation of Algorithms: Theory, Implementation, and Application.

  6. Automatic Versus Manual Indexing

    ERIC Educational Resources Information Center

    Vander Meulen, W. A.; Janssen, P. J. F. C.

    1977-01-01

    A comparative evaluation of results in terms of recall and precision from queries submitted to systems with automatic and manual subject indexing. Differences were attributed to query formulation. The effectiveness of automatic indexing was found equivalent to manual indexing. (Author/KP)

  7. Automatic Differentiation Package

    SciTech Connect

    Gay, David M.; Phipps, Eric; Bratlett, Roscoe

    2007-03-01

    Sacado is an automatic differentiation package for C++ codes using operator overloading and C++ templating. Sacado provide forward, reverse, and Taylor polynomial automatic differentiation classes and utilities for incorporating these classes into C++ codes. Users can compute derivatives of computations arising in engineering and scientific applications, including nonlinear equation solving, time integration, sensitivity analysis, stability analysis, optimization and uncertainity quantification.

  8. Automatic Test Program Generation.

    DTIC Science & Technology

    1978-03-01

    presents a test description language, NOPAL , in which a user may describe diagnostic tests, and a software system which automatically generates test...programs for an automatic test equipment based on the descriptions of tests. The software system accepts as input the tests specified in NOPAL , performs

  9. Digital automatic gain control

    NASA Technical Reports Server (NTRS)

    Uzdy, Z.

    1980-01-01

    Performance analysis, used to evaluated fitness of several circuits to digital automatic gain control (AGC), indicates that digital integrator employing coherent amplitude detector (CAD) is best device suited for application. Circuit reduces gain error to half that of conventional analog AGC while making it possible to automatically modify response of receiver to match incoming signal conditions.

  10. Automatic wire twister.

    PubMed

    Smith, J F; Rodeheaver, G T; Thacker, J G; Morgan, R F; Chang, D E; Fariss, B L; Edlich, R F

    1988-06-01

    This automatic wire twister used in surgery consists of a 6-inch needle holder attached to a twisting mechanism. The major advantage of this device is that it twists wires significantly more rapidly than the conventional manual techniques. Testing has found that the ultimate force required to disrupt the wires twisted by either the automatic wire twister or manual techniques did not differ significantly and was directly related to the number of twists. The automatic wire twister reduces the time needed for wire twisting without altering the security of the twisted wire.

  11. Automatic switching matrix

    DOEpatents

    Schlecht, Martin F.; Kassakian, John G.; Caloggero, Anthony J.; Rhodes, Bruce; Otten, David; Rasmussen, Neil

    1982-01-01

    An automatic switching matrix that includes an apertured matrix board containing a matrix of wires that can be interconnected at each aperture. Each aperture has associated therewith a conductive pin which, when fully inserted into the associated aperture, effects electrical connection between the wires within that particular aperture. Means is provided for automatically inserting the pins in a determined pattern and for removing all the pins to permit other interconnecting patterns.

  12. Automatic identification of mobile and rigid substructures in molecular dynamics simulations and fractional structural fluctuation analysis.

    PubMed

    Martínez, Leandro

    2015-01-01

    The analysis of structural mobility in molecular dynamics plays a key role in data interpretation, particularly in the simulation of biomolecules. The most common mobility measures computed from simulations are the Root Mean Square Deviation (RMSD) and Root Mean Square Fluctuations (RMSF) of the structures. These are computed after the alignment of atomic coordinates in each trajectory step to a reference structure. This rigid-body alignment is not robust, in the sense that if a small portion of the structure is highly mobile, the RMSD and RMSF increase for all atoms, resulting possibly in poor quantification of the structural fluctuations and, often, to overlooking important fluctuations associated to biological function. The motivation of this work is to provide a robust measure of structural mobility that is practical, and easy to interpret. We propose a Low-Order-Value-Optimization (LOVO) strategy for the robust alignment of the least mobile substructures in a simulation. These substructures are automatically identified by the method. The algorithm consists of the iterative superposition of the fraction of structure displaying the smallest displacements. Therefore, the least mobile substructures are identified, providing a clearer picture of the overall structural fluctuations. Examples are given to illustrate the interpretative advantages of this strategy. The software for performing the alignments was named MDLovoFit and it is available as free-software at: http://leandro.iqm.unicamp.br/mdlovofit.

  13. WOLF; automatic typing program

    USGS Publications Warehouse

    Evenden, G.I.

    1982-01-01

    A FORTRAN IV program for the Hewlett-Packard 1000 series computer provides for automatic typing operations and can, when employed with manufacturer's text editor, provide a system to greatly facilitate preparation of reports, letters and other text. The input text and imbedded control data can perform nearly all of the functions of a typist. A few of the features available are centering, titles, footnotes, indentation, page numbering (including Roman numerals), automatic paragraphing, and two forms of tab operations. This documentation contains both user and technical description of the program.

  14. AUTOMATIC COUNTING APPARATUS

    DOEpatents

    Howell, W.D.

    1957-08-20

    An apparatus for automatically recording the results of counting operations on trains of electrical pulses is described. The disadvantages of prior devices utilizing the two common methods of obtaining the count rate are overcome by this apparatus; in the case of time controlled operation, the disclosed system automatically records amy information stored by the scaler but not transferred to the printer at the end of the predetermined time controlled operations and, in the case of count controlled operation, provision is made to prevent a weak sample from occupying the apparatus for an excessively long period of time.

  15. Automaticity of Conceptual Magnitude.

    PubMed

    Gliksman, Yarden; Itamar, Shai; Leibovich, Tali; Melman, Yonatan; Henik, Avishai

    2016-02-16

    What is bigger, an elephant or a mouse? This question can be answered without seeing the two animals, since these objects elicit conceptual magnitude. How is an object's conceptual magnitude processed? It was suggested that conceptual magnitude is automatically processed; namely, irrelevant conceptual magnitude can affect performance when comparing physical magnitudes. The current study further examined this question and aimed to expand the understanding of automaticity of conceptual magnitude. Two different objects were presented and participants were asked to decide which object was larger on the screen (physical magnitude) or in the real world (conceptual magnitude), in separate blocks. By creating congruent (the conceptually larger object was physically larger) and incongruent (the conceptually larger object was physically smaller) pairs of stimuli it was possible to examine the automatic processing of each magnitude. A significant congruity effect was found for both magnitudes. Furthermore, quartile analysis revealed that the congruity was affected similarly by processing time for both magnitudes. These results suggest that the processing of conceptual and physical magnitudes is automatic to the same extent. The results support recent theories suggested that different types of magnitude processing and representation share the same core system.

  16. Automatic Program Synthesis Reports.

    ERIC Educational Resources Information Center

    Biermann, A. W.; And Others

    Some of the major results of future goals of an automatic program synthesis project are described in the two papers that comprise this document. The first paper gives a detailed algorithm for synthesizing a computer program from a trace of its behavior. Since the algorithm involves a search, the length of time required to do the synthesis of…

  17. Automatic Language Identification

    DTIC Science & Technology

    2000-08-01

    the speech utterance is hypothesized. ter performance for his HMM approach than his static ap- Finally, Thyme -Gobbel et al. [47] have also looked...1998. [47] A.E. Thyme -Gobbel and S.E. Hutchins. On using prosodic cues in automatic language identification. In International Conference on Spoken

  18. Automatic multiple applicator electrophoresis

    NASA Technical Reports Server (NTRS)

    Grunbaum, B. W.

    1977-01-01

    Easy-to-use, economical device permits electrophoresis on all known supporting media. System includes automatic multiple-sample applicator, sample holder, and electrophoresis apparatus. System has potential applicability to fields of taxonomy, immunology, and genetics. Apparatus is also used for electrofocusing.

  19. Automatic Transmission Vehicle Injuries

    PubMed Central

    Fidler, Malcolm

    1973-01-01

    Four drivers sustained severe injuries when run down by their own automatic cars while adjusting the carburettor or throttle linkages. The transmission had been left in the “Drive” position and the engine was idling. This accident is easily avoidable. PMID:4695693

  20. Automaticity of Conceptual Magnitude

    PubMed Central

    Gliksman, Yarden; Itamar, Shai; Leibovich, Tali; Melman, Yonatan; Henik, Avishai

    2016-01-01

    What is bigger, an elephant or a mouse? This question can be answered without seeing the two animals, since these objects elicit conceptual magnitude. How is an object’s conceptual magnitude processed? It was suggested that conceptual magnitude is automatically processed; namely, irrelevant conceptual magnitude can affect performance when comparing physical magnitudes. The current study further examined this question and aimed to expand the understanding of automaticity of conceptual magnitude. Two different objects were presented and participants were asked to decide which object was larger on the screen (physical magnitude) or in the real world (conceptual magnitude), in separate blocks. By creating congruent (the conceptually larger object was physically larger) and incongruent (the conceptually larger object was physically smaller) pairs of stimuli it was possible to examine the automatic processing of each magnitude. A significant congruity effect was found for both magnitudes. Furthermore, quartile analysis revealed that the congruity was affected similarly by processing time for both magnitudes. These results suggest that the processing of conceptual and physical magnitudes is automatic to the same extent. The results support recent theories suggested that different types of magnitude processing and representation share the same core system. PMID:26879153

  1. Reactor component automatic grapple

    DOEpatents

    Greenaway, Paul R.

    1982-01-01

    A grapple for handling nuclear reactor components in a medium such as liquid sodium which, upon proper seating and alignment of the grapple with the component as sensed by a mechanical logic integral to the grapple, automatically seizes the component. The mechanical logic system also precludes seizure in the absence of proper seating and alignment.

  2. Automatic transmission control method

    SciTech Connect

    Hasegawa, H.; Ishiguro, T.

    1989-07-04

    This patent describes a method of controlling an automatic transmission of an automotive vehicle. The transmission has a gear train which includes a brake for establishing a first lowest speed of the transmission, the brake acting directly on a ring gear which meshes with a pinion, the pinion meshing with a sun gear in a planetary gear train, the ring gear connected with an output member, the sun gear being engageable and disengageable with an input member of the transmission by means of a clutch. The method comprises the steps of: detecting that a shift position of the automatic transmission has been shifted to a neutral range; thereafter introducing hydraulic pressure to the brake if present vehicle velocity is below a predetermined value, whereby the brake is engaged to establish the first lowest speed; and exhausting hydraulic pressure from the brake if present vehicle velocity is higher than a predetermined value, whereby the brake is disengaged.

  3. Automatic Abstraction in Planning

    NASA Technical Reports Server (NTRS)

    Christensen, J.

    1991-01-01

    Traditionally, abstraction in planning has been accomplished by either state abstraction or operator abstraction, neither of which has been fully automatic. We present a new method, predicate relaxation, for automatically performing state abstraction. PABLO, a nonlinear hierarchical planner, implements predicate relaxation. Theoretical, as well as empirical results are presented which demonstrate the potential advantages of using predicate relaxation in planning. We also present a new definition of hierarchical operators that allows us to guarantee a limited form of completeness. This new definition is shown to be, in some ways, more flexible than previous definitions of hierarchical operators. Finally, a Classical Truth Criterion is presented that is proven to be sound and complete for a planning formalism that is general enough to include most classical planning formalisms that are based on the STRIPS assumption.

  4. Automatic speech recognition

    NASA Astrophysics Data System (ADS)

    Espy-Wilson, Carol

    2005-04-01

    Great strides have been made in the development of automatic speech recognition (ASR) technology over the past thirty years. Most of this effort has been centered around the extension and improvement of Hidden Markov Model (HMM) approaches to ASR. Current commercially-available and industry systems based on HMMs can perform well for certain situational tasks that restrict variability such as phone dialing or limited voice commands. However, the holy grail of ASR systems is performance comparable to humans-in other words, the ability to automatically transcribe unrestricted conversational speech spoken by an infinite number of speakers under varying acoustic environments. This goal is far from being reached. Key to the success of ASR is effective modeling of variability in the speech signal. This tutorial will review the basics of ASR and the various ways in which our current knowledge of speech production, speech perception and prosody can be exploited to improve robustness at every level of the system.

  5. Automatic carrier acquisition system

    NASA Technical Reports Server (NTRS)

    Bunce, R. C. (Inventor)

    1973-01-01

    An automatic carrier acquisition system for a phase locked loop (PLL) receiver is disclosed. It includes a local oscillator, which sweeps the receiver to tune across the carrier frequency uncertainty range until the carrier crosses the receiver IF reference. Such crossing is detected by an automatic acquisition detector. It receives the IF signal from the receiver as well as the IF reference. It includes a pair of multipliers which multiply the IF signal with the IF reference in phase and in quadrature. The outputs of the multipliers are filtered through bandpass filters and power detected. The output of the power detector has a signal dc component which is optimized with respect to the noise dc level by the selection of the time constants of the filters as a function of the sweep rate of the local oscillator.

  6. Automatic vehicle monitoring

    NASA Technical Reports Server (NTRS)

    Bravman, J. S.; Durrani, S. H.

    1976-01-01

    Automatic vehicle monitoring systems are discussed. In a baseline system for highway applications, each vehicle obtains position information through a Loran-C receiver in rural areas and through a 'signpost' or 'proximity' type sensor in urban areas; the vehicle transmits this information to a central station via a communication link. In an advance system, the vehicle carries a receiver for signals emitted by satellites in the Global Positioning System and uses a satellite-aided communication link to the central station. An advanced railroad car monitoring system uses car-mounted labels and sensors for car identification and cargo status; the information is collected by electronic interrogators mounted along the track and transmitted to a central station. It is concluded that automatic vehicle monitoring systems are technically feasible but not economically feasible unless a large market develops.

  7. Automatic Retinal Oximetry

    NASA Astrophysics Data System (ADS)

    Halldorsson, G. H.; Karlsson, R. A.; Hardarson, S. H.; Mura, M. Dalla; Eysteinsson, T.; Beach, J. M.; Stefansson, E.; Benediktsson, J. A.

    2007-10-01

    This paper presents a method for automating the evaluation of hemoglobin oxygen saturation in the retina. This method should prove useful for monitoring ischemic retinal diseases and the effect of treatment. In order to obtain saturation values automatically, spectral images must be registered in pairs, the vessels of the retina located and measurement points must be selected. The registration algorithm is based on a data driven approach that circumvents many of the problems that have plagued previous methods. The vessels are extracted using an algorithm based on morphological profiles and supervised classifiers. Measurement points on retinal arterioles and venules as well as reference points on the adjacent fundus are automatically selected. Oxygen saturation values along vessels are averaged to arrive at a more accurate estimate of the retinal vessel oxygen saturation. The system yields reproducible results as well as being sensitive to changes in oxygen saturation.

  8. Automatic Word Alignment

    DTIC Science & Technology

    2014-02-18

    strategy was evalu­ ated in the context of English -to-Pashto (E2P) and Pashto-to- English (P2E), a low-resource language pair. For E2P, the training and...improves the quality of automatic word alignment, for example for resource poor language pairs, thus improving Statistical Machine Translation (SMT...example for resource poor language pairs, thus improving Statistical Machine Translation (SMT) performance. 15. SUBJECT TERMS 16. SECURITY

  9. Automatic Test Equipment

    DTIC Science & Technology

    1980-02-28

    Search Terms Automatic Test Equipment Frequency Analyzers Oscilloscopes Pulse Analyzers Signal Generators "Etc." Third Level Search Guided...VAST Building Block Equipment RF Test Point Control Switch Digital Multimeter Frequency and Time Interval Meter Digital Word Generator Delay...Generator RF Amplifier, 95 Hz-2 GHz RF Amplifier, 2-4 GHz RF Amplifier, 4-8 GHz RF Amplifier, 8-12.2 GHz Signal Generator, 0.1 Hz-50 kHz

  10. Automatic Microwave Network Analysis.

    DTIC Science & Technology

    A program and procedure are developed for the automatic measurement of microwave networks using a Hewlett-Packard network analyzer and programmable calculator . The program and procedure are used in the measurement of a simple microwave two port network. These measurements are evaluated by comparing with measurements on the same network using other techniques. The programs...in the programmable calculator are listed in Appendix 1. The step by step procedure used is listed in Appendix 2. (Author)

  11. Automatic range selector

    DOEpatents

    McNeilly, Clyde E.

    1977-01-04

    A device is provided for automatically selecting from a plurality of ranges of a scale of values to which a meter may be made responsive, that range which encompasses the value of an unknown parameter. A meter relay indicates whether the unknown is of greater or lesser value than the range to which the meter is then responsive. The rotatable part of a stepping relay is rotated in one direction or the other in response to the indication from the meter relay. Various positions of the rotatable part are associated with particular scales. Switching means are sensitive to the position of the rotatable part to couple the associated range to the meter.

  12. AUTOMATIC FREQUENCY CONTROL SYSTEM

    DOEpatents

    Hansen, C.F.; Salisbury, J.D.

    1961-01-10

    A control is described for automatically matching the frequency of a resonant cavity to that of a driving oscillator. The driving oscillator is disconnected from the cavity and a secondary oscillator is actuated in which the cavity is the frequency determining element. A low frequency is mixed with the output of the driving oscillator and the resultant lower and upper sidebands are separately derived. The frequencies of the sidebands are compared with the secondary oscillator frequency. deriving a servo control signal to adjust a tuning element in the cavity and matching the cavity frequency to that of the driving oscillator. The driving oscillator may then be connected to the cavity.

  13. Automatic Speech Recognition

    NASA Astrophysics Data System (ADS)

    Potamianos, Gerasimos; Lamel, Lori; Wölfel, Matthias; Huang, Jing; Marcheret, Etienne; Barras, Claude; Zhu, Xuan; McDonough, John; Hernando, Javier; Macho, Dusan; Nadeu, Climent

    Automatic speech recognition (ASR) is a critical component for CHIL services. For example, it provides the input to higher-level technologies, such as summarization and question answering, as discussed in Chapter 8. In the spirit of ubiquitous computing, the goal of ASR in CHIL is to achieve a high performance using far-field sensors (networks of microphone arrays and distributed far-field microphones). However, close-talking microphones are also of interest, as they are used to benchmark ASR system development by providing a best-case acoustic channel scenario to compare against.

  14. Automatic readout micrometer

    DOEpatents

    Lauritzen, T.

    A measuring system is described for surveying and very accurately positioning objects with respect to a reference line. A principle use of this surveying system is for accurately aligning the electromagnets which direct a particle beam emitted from a particle accelerator. Prior art surveying systems require highly skilled surveyors. Prior art systems include, for example, optical surveying systems which are susceptible to operator reading errors, and celestial navigation-type surveying systems, with their inherent complexities. The present invention provides an automatic readout micrometer which can very accurately measure distances. The invention has a simplicity of operation which practically eliminates the possibilities of operator optical reading error, owning to the elimination of traditional optical alignments for making measurements. The invention has an extendable arm which carries a laser surveying target. The extendable arm can be continuously positioned over its entire length of travel by either a coarse of fine adjustment without having the fine adjustment outrun the coarse adjustment until a reference laser beam is centered on the target as indicated by a digital readout. The length of the micrometer can then be accurately and automatically read by a computer and compared with a standardized set of alignment measurements. Due to its construction, the micrometer eliminates any errors due to temperature changes when the system is operated within a standard operating temperature range.

  15. Automatic readout micrometer

    DOEpatents

    Lauritzen, Ted

    1982-01-01

    A measuring system is disclosed for surveying and very accurately positioning objects with respect to a reference line. A principal use of this surveying system is for accurately aligning the electromagnets which direct a particle beam emitted from a particle accelerator. Prior art surveying systems require highly skilled surveyors. Prior art systems include, for example, optical surveying systems which are susceptible to operator reading errors, and celestial navigation-type surveying systems, with their inherent complexities. The present invention provides an automatic readout micrometer which can very accurately measure distances. The invention has a simplicity of operation which practically eliminates the possibilities of operator optical reading error, owning to the elimination of traditional optical alignments for making measurements. The invention has an extendable arm which carries a laser surveying target. The extendable arm can be continuously positioned over its entire length of travel by either a coarse or fine adjustment without having the fine adjustment outrun the coarse adjustment until a reference laser beam is centered on the target as indicated by a digital readout. The length of the micrometer can then be accurately and automatically read by a computer and compared with a standardized set of alignment measurements. Due to its construction, the micrometer eliminates any errors due to temperature changes when the system is operated within a standard operating temperature range.

  16. Automatic sets and Delone sets

    NASA Astrophysics Data System (ADS)

    Barbé, A.; von Haeseler, F.

    2004-04-01

    Automatic sets D\\subset{\\bb Z}^m are characterized by having a finite number of decimations. They are equivalently generated by fixed points of certain substitution systems, or by certain finite automata. As examples, two-dimensional versions of the Thue-Morse, Baum-Sweet, Rudin-Shapiro and paperfolding sequences are presented. We give a necessary and sufficient condition for an automatic set D\\subset{\\bb Z}^m to be a Delone set in {\\bb R}^m . The result is then extended to automatic sets that are defined as fixed points of certain substitutions. The morphology of automatic sets is discussed by means of examples.

  17. Automatic dynamic mask extraction for PIV images containing an unsteady interface, bubbles, and a moving structure

    NASA Astrophysics Data System (ADS)

    Dussol, David; Druault, Philippe; Mallat, Bachar; Delacroix, Sylvain; Germain, Grégory

    2016-07-01

    When performing Particle Image Velocimetry (PIV) measurements in complex fluid flows with moving interfaces and a two-phase flow, it is necessary to develop a mask to remove non-physical measurements. This is the case when studying, for example, the complex bubble sweep-down phenomenon observed in oceanographic research vessels. Indeed, in such a configuration, the presence of an unsteady free surface, of a solid-liquid interface and of bubbles in the PIV frame, leads to generate numerous laser reflections and therefore spurious velocity vectors. In this note, an image masking process is developed to successively identify the boundaries of the ship and the free surface interface. As the presence of the solid hull surface induces laser reflections, the hull edge contours are simply detected in the first PIV frame and dynamically estimated for consecutive ones. As for the unsteady surface determination, a specific process is implemented like the following: i) the edge detection of the gradient magnitude in the PIV frame, ii) the extraction of the particles by filtering high-intensity large areas related to the bubbles and/or hull reflections, iii) the extraction of the rough region containing these particles and their reflections, iv) the removal of these reflections. The unsteady surface is finally obtained with a fifth-order polynomial interpolation. The resulted free surface is successfully validated from the Fourier analysis and by visualizing selected PIV images containing numerous spurious high intensity areas. This paper demonstrates how this data analysis process leads to PIV images database without reflections and an automatic detection of both the free surface and the rigid body. An application of this new mask is finally detailed, allowing a preliminary analysis of the hydrodynamic flow.

  18. Automatic MR volume registration and its evaluation for the pelvis and prostate

    NASA Astrophysics Data System (ADS)

    Fei, Baowei; Wheaton, Andrew; Lee, Zhenghong; Duerk, Jeffrey L.; Wilson, David L.

    2002-03-01

    A three-dimensional (3D) mutual information registration method was created and used to register MRI volumes of the pelvis and prostate. It had special features to improve robustness. First, it used a multi-resolution approach and performed registration from low to high resolution. Second, it used two similarity measures, correlation coefficient at lower resolutions and mutual information at full resolution, because of their particular advantages. Third, we created a method to avoid local minima by restarting the registration with randomly perturbed parameters. The criterion for restarting was a correlation coefficient below an empirically determined threshold. Experiments determined the accuracy of registration under conditions found in potential applications in prostate cancer diagnosis, staging, treatment and interventional MRI (iMRI) guided therapies. Images were acquired in the diagnostic (supine) and treatment position (supine with legs raised). Images were also acquired as a function of bladder filling and the time interval between imaging sessions. Overall studies on three patients and three healthy volunteers, when both volumes in a pair were obtained in the diagnostic position under comparable conditions, bony landmarks and prostate 3D centroids were aligned within 1.6 +/- 0.2 mm and 1.4 +/- 0.2 mm, respectively, values only slightly larger than a voxel. Analysis suggests that actual errors are smaller because of the uncertainty in landmark localization and prostate segmentation. Between the diagnostic and treatment positions, bony landmarks continued to register well, but prostate centroids moved towards the posterior 2.8-3.4 mm. Manual cropping to remove voxels in the legs was necessary to register these images. In conclusion, automatic, rigid body registration is probably sufficiently accurate for many applications in prostate cancer. For potential iMRI-guided treatments, the small prostate displacement between the diagnostic and treatment positions

  19. Automatic vehicle location system

    NASA Technical Reports Server (NTRS)

    Hansen, G. R., Jr. (Inventor)

    1973-01-01

    An automatic vehicle detection system is disclosed, in which each vehicle whose location is to be detected carries active means which interact with passive elements at each location to be identified. The passive elements comprise a plurality of passive loops arranged in a sequence along the travel direction. Each of the loops is tuned to a chosen frequency so that the sequence of the frequencies defines the location code. As the vehicle traverses the sequence of the loops as it passes over each loop, signals only at the frequency of the loop being passed over are coupled from a vehicle transmitter to a vehicle receiver. The frequencies of the received signals in the receiver produce outputs which together represent a code of the traversed location. The code location is defined by a painted pattern which reflects light to a vehicle carried detector whose output is used to derive the code defined by the pattern.

  20. Automatic routing module

    NASA Technical Reports Server (NTRS)

    Malin, Janice A.

    1987-01-01

    Automatic Routing Module (ARM) is a tool to partially automate Air Launched Cruise Missile (ALCM) routing. For any accessible launch point or target pair, ARM creates flyable routes that, within the fidelity of the models, are optimal in terms of threat avoidance, clobber avoidance, and adherence to vehicle and planning constraints. Although highly algorithmic, ARM is an expert system. Because of the heuristics applied, ARM generated routes closely resemble manually generated routes in routine cases. In more complex cases, ARM's ability to accumulate and assess threat danger in three dimensions and trade that danger off with the probability of ground clobber results in the safest path around or through difficult areas. The tools available prior to ARM did not provide the planner with enough information or present it in such a way that ensured he would select the safest path.

  1. AUTOMATIC HAND COUNTER

    DOEpatents

    Mann J.R.; Wainwright, A.E.

    1963-06-11

    An automatic, personnel-operated, alpha-particle hand monitor is described which functions as a qualitative instrument to indicate to the person using it whether his hands are cold'' or hot.'' The monitor is activated by a push button and includes several capacitor-triggered thyratron tubes. Upon release of the push button, the monitor starts the counting of the radiation present on the hands of the person. If the count of the radiation exceeds a predetermined level within a predetermined time, then a capacitor will trigger a first thyratron tube to light a hot'' lamp. If, however, the count is below such level during this time period, another capacitor will fire a second thyratron to light a safe'' lamp. (AEC)

  2. Automatic Bayesian polarity determination

    NASA Astrophysics Data System (ADS)

    Pugh, D. J.; White, R. S.; Christie, P. A. F.

    2016-07-01

    The polarity of the first motion of a seismic signal from an earthquake is an important constraint in earthquake source inversion. Microseismic events often have low signal-to-noise ratios, which may lead to difficulties estimating the correct first-motion polarities of the arrivals. This paper describes a probabilistic approach to polarity picking that can be both automated and combined with manual picking. This approach includes a quantitative estimate of the uncertainty of the polarity, improving calculation of the polarity probability density function for source inversion. It is sufficiently fast to be incorporated into an automatic processing workflow. When used in source inversion, the results are consistent with those from manual observations. In some cases, they produce a clearer constraint on the range of high-probability source mechanisms, and are better constrained than source mechanisms determined using a uniform probability of an incorrect polarity pick.

  3. Networked Automatic Optical Telescopes

    NASA Astrophysics Data System (ADS)

    Mattox, J. R.

    2000-05-01

    Many groups around the world are developing automated or robotic optical observatories. The coordinated operation of automated optical telescopes at diverse sites could provide observing prospects which are not otherwise available, e.g., continuous optical photometry without diurnal interruption. Computer control and scheduling also offers the prospect of effective response to transient events such as γ -ray bursts. These telescopes could also serve science education by providing high-quality CCD data for educators and students. The Automatic Telescope Network (ATN) project has been undertaken to promote networking of automated telescopes. A web site is maintained at http://gamma.bu.edu/atn/. The development of such networks will be facilitated by the existence of standards. A set of standard commands for instrument and telescope control systems will allow for the creation of software for an ``observatory control system'' which can be used at any facility which complies with the TCS and ICS standards. Also, there is a strong need for standards for the specification of observations to be done, and reports on the results and status of observations. A proposed standard for this is the Remote Telescope Markup Language (RTML), which is expected to be described in another poster in this session. It may thus be feasible for amateur-astronomers to soon buy all necessary equipment and software to field an automatic telescope. The owner/operator could make otherwise unused telescope time available to the network in exchange for the utilization of other telescopes in the network --- including occasional utilization of meter-class telescopes with research-grade CCD detectors at good sites.

  4. Automatic Coal-Mining System

    NASA Technical Reports Server (NTRS)

    Collins, E. R., Jr.

    1985-01-01

    Coal cutting and removal done with minimal hazard to people. Automatic coal mine cutting, transport and roof-support movement all done by automatic machinery. Exposure of people to hazardous conditions reduced to inspection tours, maintenance, repair, and possibly entry mining.

  5. Automatic Command Sequence Generation

    NASA Technical Reports Server (NTRS)

    Fisher, Forest; Gladded, Roy; Khanampompan, Teerapat

    2007-01-01

    Automatic Sequence Generator (Autogen) Version 3.0 software automatically generates command sequences for the Mars Reconnaissance Orbiter (MRO) and several other JPL spacecraft operated by the multi-mission support team. Autogen uses standard JPL sequencing tools like APGEN, ASP, SEQGEN, and the DOM database to automate the generation of uplink command products, Spacecraft Command Message Format (SCMF) files, and the corresponding ground command products, DSN Keywords Files (DKF). Autogen supports all the major multi-mission mission phases including the cruise, aerobraking, mapping/science, and relay mission phases. Autogen is a Perl script, which functions within the mission operations UNIX environment. It consists of two parts: a set of model files and the autogen Perl script. Autogen encodes the behaviors of the system into a model and encodes algorithms for context sensitive customizations of the modeled behaviors. The model includes knowledge of different mission phases and how the resultant command products must differ for these phases. The executable software portion of Autogen, automates the setup and use of APGEN for constructing a spacecraft activity sequence file (SASF). The setup includes file retrieval through the DOM (Distributed Object Manager), an object database used to store project files. This step retrieves all the needed input files for generating the command products. Depending on the mission phase, Autogen also uses the ASP (Automated Sequence Processor) and SEQGEN to generate the command product sent to the spacecraft. Autogen also provides the means for customizing sequences through the use of configuration files. By automating the majority of the sequencing generation process, Autogen eliminates many sequence generation errors commonly introduced by manually constructing spacecraft command sequences. Through the layering of commands into the sequence by a series of scheduling algorithms, users are able to rapidly and reliably construct the

  6. Automatic transmission structure

    SciTech Connect

    Iwase, Y.; Morisawa, K.

    1987-03-24

    An automatic transmission is described comprising: an output shaft of the transmission including a stepped portion; a parking gear spline-connected with the output shaft on a first side of the stepped portion; a plurality of governor values mounted on a rear side of the parking gear and radially disposed around the output shaft on the first side of the stepped portion; a speed meter drive gear spline-connected with the output shaft on a second side of the stepped portion and on a rear side of the governor valves; and an annular spacer fitted on the output shaft on the second side of the stepped portion between the governor valves and the speed meter drive gear to abut on each of the governor valves and the speed meter drive gear. The annular member is constructed separately from the speed meter drive gear and has an outer diameter larger than an outer diameter of the speed meter drive gear thereby resulting in a contact area between the annular space and the speed meter drive gear which is smaller than a contact area between the annular spacer and the rear side of the governor valves; the drive gear being axially secured relative to the output shaft by a bearing thereby enabling a fixed axial positioning of the annular spacer on the output shaft.

  7. Electronically controlled automatic transmission

    SciTech Connect

    Ohkubo, M.; Shiba, H.; Nakamura, K.

    1989-03-28

    This patent describes an electronically controlled automatic transmission having a manual valve working in connection with a manual shift lever, shift valves operated by solenoid valves which are driven by an electronic control circuit previously memorizing shift patterns, and a hydraulic circuit controlled by these manual valve and shift valves for driving brakes and a clutch in order to change speed. Shift patterns of 2-range and L-range, in addition to a shift pattern of D-range, are memorized previously in the electronic control circuit, an operation switch is provided which changes the shift pattern of the electronic control circuit to any shift pattern among those of D-range, 2-range and L-range at time of the manual shift lever being in a D-range position, a releasable lock mechanism is provided which prevents the manual shift lever from entering 2-range and L-range positions, and the hydraulic circuit is set to a third speed mode when the manual shift lever is in the D-range position. The circuit is set to a second speed mode when it is in the 2-range position, and the circuit is set to a first speed mode when it is in the L-range position, respectively, in case where the shift valves are not working.

  8. Automatic Welding System

    NASA Technical Reports Server (NTRS)

    1982-01-01

    Robotic welding has been of interest to industrial firms because it offers higher productivity at lower cost than manual welding. There are some systems with automated arc guidance available, but they have disadvantages, such as limitations on types of materials or types of seams that can be welded; susceptibility to stray electrical signals; restricted field of view; or tendency to contaminate the weld seam. Wanting to overcome these disadvantages, Marshall Space Flight Center, aided by Hayes International Corporation, developed system that uses closed-circuit TV signals for automatic guidance of the welding torch. NASA granted license to Combined Technologies, Inc. for commercial application of the technology. They developed a refined and improved arc guidance system. CTI in turn, licensed the Merrick Corporation, also of Nashville, for marketing and manufacturing of the new system, called the CT2 Optical Trucker. CT2 is a non-contracting system that offers adaptability to broader range of welding jobs and provides greater reliability in high speed operation. It is extremely accurate and can travel at high speed of up to 150 inches per minute.

  9. Automatic imitation in dogs

    PubMed Central

    Range, Friederike; Huber, Ludwig; Heyes, Cecilia

    2011-01-01

    After preliminary training to open a sliding door using their head and their paw, dogs were given a discrimination task in which they were rewarded with food for opening the door using the same method (head or paw) as demonstrated by their owner (compatible group), or for opening the door using the alternative method (incompatible group). The incompatible group, which had to counterimitate to receive food reward, required more trials to reach a fixed criterion of discrimination performance (85% correct) than the compatible group. This suggests that, like humans, dogs are subject to ‘automatic imitation’; they cannot inhibit online the tendency to imitate head use and/or paw use. In a subsequent transfer test, where all dogs were required to imitate their owners' head and paw use for food reward, the incompatible group made a greater proportion of incorrect, counterimitative responses than the compatible group. These results are consistent with the associative sequence learning model, which suggests that the development of imitation depends on sensorimotor experience and phylogenetically general mechanisms of associative learning. More specifically, they suggest that the imitative behaviour of dogs is shaped more by their developmental interactions with humans than by their evolutionary history of domestication. PMID:20667875

  10. Automatic aircraft recognition

    NASA Astrophysics Data System (ADS)

    Hmam, Hatem; Kim, Jijoong

    2002-08-01

    Automatic aircraft recognition is very complex because of clutter, shadows, clouds, self-occlusion and degraded imaging conditions. This paper presents an aircraft recognition system, which assumes from the start that the image is possibly degraded, and implements a number of strategies to overcome edge fragmentation and distortion. The current vision system employs a bottom up approach, where recognition begins by locating image primitives (e.g., lines and corners), which are then combined in an incremental fashion into larger sets of line groupings using knowledge about aircraft, as viewed from a generic viewpoint. Knowledge about aircraft is represented in the form of whole/part shape description and the connectedness property, and is embedded in production rules, which primarily aim at finding instances of the aircraft parts in the image and checking the connectedness property between the parts. Once a match is found, a confidence score is assigned and as evidence in support of an aircraft interpretation is accumulated, the score is increased proportionally. Finally a selection of the resulting image interpretations with the highest scores, is subjected to competition tests, and only non-ambiguous interpretations are allowed to survive. Experimental results demonstrating the effectiveness of the current recognition system are given.

  11. Automatic programming of simulation models

    NASA Technical Reports Server (NTRS)

    Schroer, Bernard J.; Tseng, Fan T.; Zhang, Shou X.; Dwan, Wen S.

    1988-01-01

    The objective of automatic programming is to improve the overall environment for describing the program. This improved environment is realized by a reduction in the amount of detail that the programmer needs to know and is exposed to. Furthermore, this improved environment is achieved by a specification language that is more natural to the user's problem domain and to the user's way of thinking and looking at the problem. The goal of this research is to apply the concepts of automatic programming (AP) to modeling discrete event simulation system. Specific emphasis is on the design and development of simulation tools to assist the modeler define or construct a model of the system and to then automatically write the corresponding simulation code in the target simulation language, GPSS/PC. A related goal is to evaluate the feasibility of various languages for constructing automatic programming simulation tools.

  12. Clothes Dryer Automatic Termination Evaluation

    SciTech Connect

    TeGrotenhuis, Ward E.

    2014-10-01

    Volume 2: Improved Sensor and Control Designs Many residential clothes dryers on the market today provide automatic cycles that are intended to stop when the clothes are dry, as determined by the final remaining moisture content (RMC). However, testing of automatic termination cycles has shown that many dryers are susceptible to over-drying of loads, leading to excess energy consumption. In particular, tests performed using the DOE Test Procedure in Appendix D2 of 10 CFR 430 subpart B have shown that as much as 62% of the energy used in a cycle may be from over-drying. Volume 1 of this report shows an average of 20% excess energy from over-drying when running automatic cycles with various load compositions and dryer settings. Consequently, improving automatic termination sensors and algorithms has the potential for substantial energy savings in the U.S.

  13. Automatic pump for deep wells

    SciTech Connect

    Brown, K.D.

    1981-11-24

    An automatic pump for deep wells comprises a long stroke reciprocating pump having its piston normally in its bottom position and an automatic control dependent upon the collection of a predetermined amount of liquid in the pump cylinder above the piston for actuating the piston to pump the liquid into a production line. The automatic control includes an electric motor driven hydraulic pump and a reservoir of hydraulic fluid which is actuated upon filling of the reciprocating pump chamber to supply hydraulic fluid to a closed chamber below the piston and force the piston upwardly to discharge liquid from the pump cylinder. Gas collected in the top of the pump cylinder results in low starting current and a saving of energy. The hydraulic pump is reversed automatically upon completion of the pumping stroke of the piston.

  14. Statistical Approaches to Automatic Indexing.

    ERIC Educational Resources Information Center

    Harter, Stephen P.

    1978-01-01

    Views automatic indexing as a two-tiered word frequency analysis that involves selection of a technical vocabulary and identification of document keywords. Assumptions, criteria, evaluation, and relevance are discussed. (JD)

  15. Automatic Classification in Information Retrieval.

    ERIC Educational Resources Information Center

    van Rijsbergen, C. J.

    1978-01-01

    Addresses the application of automatic classification methods to the problems associated with computerized document retrieval. Different kinds of classifications are described, and both document and term clustering methods are discussed. References and notes are provided. (Author/JD)

  16. Automatic safety rod for reactors

    DOEpatents

    Germer, John H.

    1988-01-01

    An automatic safety rod for a nuclear reactor containing neutron absorbing material and designed to be inserted into a reactor core after a loss-of-core flow. Actuation is based upon either a sudden decrease in core pressure drop or the pressure drop decreases below a predetermined minimum value. The automatic control rod includes a pressure regulating device whereby a controlled decrease in operating pressure due to reduced coolant flow does not cause the rod to drop into the core.

  17. Automatic Collision Avoidance Technology (ACAT)

    NASA Technical Reports Server (NTRS)

    Swihart, Donald E.; Skoog, Mark A.

    2007-01-01

    This document represents two views of the Automatic Collision Avoidance Technology (ACAT). One viewgraph presentation reviews the development and system design of Automatic Collision Avoidance Technology (ACAT). Two types of ACAT exist: Automatic Ground Collision Avoidance (AGCAS) and Automatic Air Collision Avoidance (AACAS). The AGCAS Uses Digital Terrain Elevation Data (DTED) for mapping functions, and uses Navigation data to place aircraft on map. It then scans DTED in front of and around aircraft and uses future aircraft trajectory (5g) to provide automatic flyup maneuver when required. The AACAS uses data link to determine position and closing rate. It contains several canned maneuvers to avoid collision. Automatic maneuvers can occur at last instant and both aircraft maneuver when using data link. The system can use sensor in place of data link. The second viewgraph presentation reviews the development of a flight test and an evaluation of the test. A review of the operation and comparison of the AGCAS and a pilot's performance are given. The same review is given for the AACAS is given.

  18. 12 CFR 925.4 - Automatic membership.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 12 Banks and Banking 7 2010-01-01 2010-01-01 false Automatic membership. 925.4 Section 925.4 Banks... MEMBERS OF THE BANKS Membership Application Process § 925.4 Automatic membership. (a) Automatic membership... between the member and the Bank at the time of such conversion may continue. (b) Automatic membership...

  19. Automatic programming of simulation models

    NASA Technical Reports Server (NTRS)

    Schroer, Bernard J.; Tseng, Fan T.; Zhang, Shou X.; Dwan, Wen S.

    1990-01-01

    The concepts of software engineering were used to improve the simulation modeling environment. Emphasis was placed on the application of an element of rapid prototyping, or automatic programming, to assist the modeler define the problem specification. Then, once the problem specification has been defined, an automatic code generator is used to write the simulation code. The following two domains were selected for evaluating the concepts of software engineering for discrete event simulation: manufacturing domain and a spacecraft countdown network sequence. The specific tasks were to: (1) define the software requirements for a graphical user interface to the Automatic Manufacturing Programming System (AMPS) system; (2) develop a graphical user interface for AMPS; and (3) compare the AMPS graphical interface with the AMPS interactive user interface.

  20. Automatic rapid attachable warhead section

    DOEpatents

    Trennel, Anthony J.

    1994-05-10

    Disclosed are a method and apparatus for (1) automatically selecting warheads or reentry vehicles from a storage area containing a plurality of types of warheads or reentry vehicles, (2) automatically selecting weapon carriers from a storage area containing at least one type of weapon carrier, (3) manipulating and aligning the selected warheads or reentry vehicles and weapon carriers, and (4) automatically coupling the warheads or reentry vehicles with the weapon carriers such that coupling of improperly selected warheads or reentry vehicles with weapon carriers is inhibited. Such inhibition enhances safety of operations and is achieved by a number of means including computer control of the process of selection and coupling and use of connectorless interfaces capable of assuring that improperly selected items will be rejected or rendered inoperable prior to coupling. Also disclosed are a method and apparatus wherein the stated principles pertaining to selection, coupling and inhibition are extended to apply to any item-to-be-carried and any carrying assembly.

  1. Automatic rapid attachable warhead section

    DOEpatents

    Trennel, A.J.

    1994-05-10

    Disclosed are a method and apparatus for automatically selecting warheads or reentry vehicles from a storage area containing a plurality of types of warheads or reentry vehicles, automatically selecting weapon carriers from a storage area containing at least one type of weapon carrier, manipulating and aligning the selected warheads or reentry vehicles and weapon carriers, and automatically coupling the warheads or reentry vehicles with the weapon carriers such that coupling of improperly selected warheads or reentry vehicles with weapon carriers is inhibited. Such inhibition enhances safety of operations and is achieved by a number of means including computer control of the process of selection and coupling and use of connectorless interfaces capable of assuring that improperly selected items will be rejected or rendered inoperable prior to coupling. Also disclosed are a method and apparatus wherein the stated principles pertaining to selection, coupling and inhibition are extended to apply to any item-to-be-carried and any carrying assembly. 10 figures.

  2. Grinding Parts For Automatic Welding

    NASA Technical Reports Server (NTRS)

    Burley, Richard K.; Hoult, William S.

    1989-01-01

    Rollers guide grinding tool along prospective welding path. Skatelike fixture holds rotary grinder or file for machining large-diameter rings or ring segments in preparation for welding. Operator grasps handles to push rolling fixture along part. Rollers maintain precise dimensional relationship so grinding wheel cuts precise depth. Fixture-mounted grinder machines surface to quality sufficient for automatic welding; manual welding with attendant variations and distortion not necessary. Developed to enable automatic welding of parts, manual welding of which resulted in weld bead permeated with microscopic fissures.

  3. Algorithms for skiascopy measurement automatization

    NASA Astrophysics Data System (ADS)

    Fomins, Sergejs; Trukša, Renārs; KrūmiĆa, Gunta

    2014-10-01

    Automatic dynamic infrared retinoscope was developed, which allows to run procedure at a much higher rate. Our system uses a USB image sensor with up to 180 Hz refresh rate equipped with a long focus objective and 850 nm infrared light emitting diode as light source. Two servo motors driven by microprocessor control the rotation of semitransparent mirror and motion of retinoscope chassis. Image of eye pupil reflex is captured via software and analyzed along the horizontal plane. Algorithm for automatic accommodative state analysis is developed based on the intensity changes of the fundus reflex.

  4. Automatic interpretation of Schlumberger soundings

    SciTech Connect

    Ushijima, K.

    1980-09-01

    The automatic interpretation of apparent resistivity curves from horizontally layered earth models is carried out by the curve-fitting method in three steps: (1) the observed VES data are interpolated at equidistant points of electrode separations on the logarithmic scale by using the cubic spline function, (2) the layer parameters which are resistivities and depths are predicted from the sampled apparent resistivity values by SALS system program and (3) the theoretical VES curves from the models are calculated by Ghosh's linear filter method using the Zhody's computer program. Two soundings taken over Takenoyu geothermal area were chosen to test the procedures of the automatic interpretation.

  5. Automatic diluter for bacteriological samples.

    PubMed Central

    Trinel, P A; Bleuze, P; Leroy, G; Moschetto, Y; Leclerc, H

    1983-01-01

    The described apparatus, carrying 190 tubes, allows automatic and aseptic dilution of liquid or suspended-solid samples. Serial 10-fold dilutions are programmable from 10(-1) to 10(-9) and are carried out in glass tubes with screw caps and split silicone septa. Dilution assays performed with strains of Escherichia coli and Bacillus stearothermophilus permitted efficient conditions for sterilization of the needle to be defined and showed that the automatic dilutions were as accurate and as reproducible as the most rigorous conventional dilutions. Images PMID:6338826

  6. Traduction automatique et terminologie automatique (Automatic Translation and Automatic Terminology

    ERIC Educational Resources Information Center

    Dansereau, Jules

    1978-01-01

    An exposition of reasons why a system of automatic translation could not use a terminology bank except as a source of information. The fundamental difference between the two tools is explained and examples of translation and mistranslation are given as evidence of the limits and possibilities of each process. (Text is in French.) (AMH)

  7. Automatic Error Analysis Using Intervals

    ERIC Educational Resources Information Center

    Rothwell, E. J.; Cloud, M. J.

    2012-01-01

    A technique for automatic error analysis using interval mathematics is introduced. A comparison to standard error propagation methods shows that in cases involving complicated formulas, the interval approach gives comparable error estimates with much less effort. Several examples are considered, and numerical errors are computed using the INTLAB…

  8. Automatic Recognition of Deaf Speech.

    ERIC Educational Resources Information Center

    Abdelhamied, Kadry; And Others

    1990-01-01

    This paper describes a speech perception system for automatic recognition of deaf speech. Using a 2-step segmentation approach for 468 utterances by 2 hearing-impaired men and 2 normal-hearing men, rates as high as 93.01 percent and 81.81 percent recognition were obtained in recognizing from deaf speech isolated words and connected speech,…

  9. Automatic calculation in quarkonium physics

    NASA Astrophysics Data System (ADS)

    Gong, Bin; Wan, Lu-Ping; Wang, Jian-Xiong; Zhang, Hong-Fei

    2014-06-01

    In this report, an automatic calculating package based on REDUCE and RLISP, FDC, is introduced, especially its one-loop calculation part and its special treatment for quarkonium physics. With FDC, many works have been completed, most of them are very important in solve/clarify current puzzles in quarkonium physics.

  10. Automatic Identification of Metaphoric Utterances

    ERIC Educational Resources Information Center

    Dunn, Jonathan Edwin

    2013-01-01

    This dissertation analyzes the problem of metaphor identification in linguistic and computational semantics, considering both manual and automatic approaches. It describes a manual approach to metaphor identification, the Metaphoricity Measurement Procedure (MMP), and compares this approach with other manual approaches. The dissertation then…

  11. Robust methods for automatic image-to-world registration in cone-beam CT interventional guidance

    SciTech Connect

    Dang, H.; Otake, Y.; Schafer, S.; Stayman, J. W.; Kleinszig, G.; Siewerdsen, J. H.

    2012-10-15

    Purpose: Real-time surgical navigation relies on accurate image-to-world registration to align the coordinate systems of the image and patient. Conventional manual registration can present a workflow bottleneck and is prone to manual error and intraoperator variability. This work reports alternative means of automatic image-to-world registration, each method involving an automatic registration marker (ARM) used in conjunction with C-arm cone-beam CT (CBCT). The first involves a Known-Model registration method in which the ARM is a predefined tool, and the second is a Free-Form method in which the ARM is freely configurable. Methods: Studies were performed using a prototype C-arm for CBCT and a surgical tracking system. A simple ARM was designed with markers comprising a tungsten sphere within infrared reflectors to permit detection of markers in both x-ray projections and by an infrared tracker. The Known-Model method exercised a predefined specification of the ARM in combination with 3D-2D registration to estimate the transformation that yields the optimal match between forward projection of the ARM and the measured projection images. The Free-Form method localizes markers individually in projection data by a robust Hough transform approach extended from previous work, backprojected to 3D image coordinates based on C-arm geometric calibration. Image-domain point sets were transformed to world coordinates by rigid-body point-based registration. The robustness and registration accuracy of each method was tested in comparison to manual registration across a range of body sites (head, thorax, and abdomen) of interest in CBCT-guided surgery, including cases with interventional tools in the radiographic scene. Results: The automatic methods exhibited similar target registration error (TRE) and were comparable or superior to manual registration for placement of the ARM within {approx}200 mm of C-arm isocenter. Marker localization in projection data was robust across all

  12. Manual and Automatic Lineament Mapping: Comparing Results

    NASA Astrophysics Data System (ADS)

    Vaz, D. A.; di Achille, G.; Barata, M. T.; Alves, E. I.

    2008-03-01

    A method for automatic lineament extraction using topographic data is applied on the Thaumasia plateau. A comparison is made between the results that are obtained from the automatic mapping approach and from a traditional tectonic lineament mapping.

  13. Self-Compassion and Automatic Thoughts

    ERIC Educational Resources Information Center

    Akin, Ahmet

    2012-01-01

    The aim of this research is to examine the relationships between self-compassion and automatic thoughts. Participants were 299 university students. In this study, the Self-compassion Scale and the Automatic Thoughts Questionnaire were used. The relationships between self-compassion and automatic thoughts were examined using correlation analysis…

  14. 8 CFR 1205.1 - Automatic revocation.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 8 Aliens and Nationality 1 2010-01-01 2010-01-01 false Automatic revocation. 1205.1 Section 1205.1... REGULATIONS REVOCATION OF APPROVAL OF PETITIONS § 1205.1 Automatic revocation. (a) Reasons for automatic revocation. The approval of a petition or self-petition made under section 204 of the Act and in...

  15. 8 CFR 205.1 - Automatic revocation.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 8 Aliens and Nationality 1 2010-01-01 2010-01-01 false Automatic revocation. 205.1 Section 205.1 Aliens and Nationality DEPARTMENT OF HOMELAND SECURITY IMMIGRATION REGULATIONS REVOCATION OF APPROVAL OF PETITIONS § 205.1 Automatic revocation. (a) Reasons for automatic revocation. The approval of a petition...

  16. 12 CFR 1263.4 - Automatic membership.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 12 Banks and Banking 9 2012-01-01 2012-01-01 false Automatic membership. 1263.4 Section 1263.4 Banks and Banking FEDERAL HOUSING FINANCE AGENCY FEDERAL HOME LOAN BANKS MEMBERS OF THE BANKS Membership Application Process § 1263.4 Automatic membership. (a) Automatic membership for certain charter...

  17. 12 CFR 1263.4 - Automatic membership.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 12 Banks and Banking 7 2011-01-01 2011-01-01 false Automatic membership. 1263.4 Section 1263.4 Banks and Banking FEDERAL HOUSING FINANCE AGENCY FEDERAL HOME LOAN BANKS MEMBERS OF THE BANKS Membership Application Process § 1263.4 Automatic membership. (a) Automatic membership for certain charter...

  18. 12 CFR 1263.4 - Automatic membership.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 12 Banks and Banking 10 2014-01-01 2014-01-01 false Automatic membership. 1263.4 Section 1263.4 Banks and Banking FEDERAL HOUSING FINANCE AGENCY FEDERAL HOME LOAN BANKS MEMBERS OF THE BANKS Membership Application Process § 1263.4 Automatic membership. (a) Automatic membership for certain charter...

  19. 12 CFR 1263.4 - Automatic membership.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 12 Banks and Banking 9 2013-01-01 2013-01-01 false Automatic membership. 1263.4 Section 1263.4 Banks and Banking FEDERAL HOUSING FINANCE AGENCY FEDERAL HOME LOAN BANKS MEMBERS OF THE BANKS Membership Application Process § 1263.4 Automatic membership. (a) Automatic membership for certain charter...

  20. Adding Automatic Evaluation to Interactive Virtual Labs

    ERIC Educational Resources Information Center

    Farias, Gonzalo; Muñoz de la Peña, David; Gómez-Estern, Fabio; De la Torre, Luis; Sánchez, Carlos; Dormido, Sebastián

    2016-01-01

    Automatic evaluation is a challenging field that has been addressed by the academic community in order to reduce the assessment workload. In this work we present a new element for the authoring tool Easy Java Simulations (EJS). This element, which is named automatic evaluation element (AEE), provides automatic evaluation to virtual and remote…

  1. Automatic registration between reference and on-board digital tomosynthesis images for positioning verification.

    PubMed

    Ren, Lei; Godfrey, Devon J; Yan, Hui; Wu, Q Jackie; Yin, Fang-Fang

    2008-02-01

    The authors developed a hybrid multiresolution rigid-body registration technique to automatically register reference digital tomosynthesis (DTS) images with on-board DTS images to guide patient positioning in radiation therapy. This hybrid registration technique uses a faster but less accurate static method to achieve an initial registration, followed by a slower but more accurate adaptive method to fine tune the registration. A multiresolution scheme is employed in the registration to further improve the registration accuracy, robustness, and efficiency. Normalized mutual information is selected as the criterion for the similarity measure and the downhill simplex method is used as the search engine. This technique was tested using image data both from an anthropomorphic chest phantom and from eight head-and-neck cancer patients. The effects of the scan angle and the region-of-interest (ROI) size on the registration accuracy and robustness were investigated. The necessity of using the adaptive registration method in the hybrid technique was validated by comparing the results of the static method and the hybrid method. With a 44 degrees scan angle and a large ROI covering the entire DTS volume, the average of the registration capture ranges in single-axis simulations was between -31 and +34 deg for rotations and between -89 and +78 mm for translations in the phantom study, and between -38 and +38 deg for rotations and between -58 and +65 mm for translations in the patient study. Decreasing the DTS scan angle from 44 degrees to 22 degrees mainly degraded the registration accuracy and robustness for the out-of-plane rotations. Decreasing the ROI size from the entire DTS volume to the volume surrounding the spinal cord reduced the capture ranges to between -23 and +18 deg for rotations and between -33 and +43 mm for translations in the phantom study, and between -18 and +25 deg for rotations and between -35 and +39 mm for translations in the patient study. Results also

  2. Rigid Body Attitude Control Based on a Manifold Representation of Direction Cosine Matrices

    NASA Astrophysics Data System (ADS)

    Nakath, David; Clemens, Joachim; Rachuy, Carsten

    2017-01-01

    Autonomous systems typically actively observe certain aspects of their surroundings, which makes them dependent on a suitable controller. However, building an attitude controller for three degrees of freedom is a challenging task, mainly due to singularities in the different parametrizations of the three dimensional rotation group SO(3). Thus, we propose an attitude controller based on a manifold representation of direction cosine matrices: In state space, the attitude is globally and uniquely represented as a direction cosine matrix R ∈ SO(3). However, differences in the state space, i.e., the attitude errors, are exposed to the controller in the vector space ℝ3. This is achieved by an operator, which integrates the matrix logarithm mapping from SO(3) to so(3) and the map from so(3) to ℝ3. Based on this representation, we derive a proportional and derivative feedback controller, whose output has an upper bound to prevent actuator saturation. Additionally, the feedback is preprocessed by a particle filter to account for measurement and state transition noise. We evaluate our approach in a simulator in three different spacecraft maneuver scenarios: (i) stabilizing, (ii) rest-to-rest, and (iii) nadir-pointing. The controller exhibits stable behavior from initial attitudes near and far from the setpoint. Furthermore, it is able to stabilize a spacecraft and can be used for nadir-pointing maneuvers.

  3. Design and Implementation of MARG Sensors for 3-DOF Orientation Measurement of Rigid Bodies

    DTIC Science & Technology

    2003-09-01

    IEEE Transactions on Robotics and Automation, Vol. 11, No.3, pp. 328-342, June 1995. 7. Sykkarieh, S., Nebot, E., & Durrant...Whyte, H., "A High Integrity IMU/GPS Navigation Loop for Autonomous Land Vehicle Applications," IEEE Transactions on Robotics and Automation, Vol. 15...Measurement Unit Using Vehicle Model Constraints for Land Vehicle Applications," IEEE Transactions on Robotics and Automation, Vol. 17, No. 5, pp.

  4. Rotation elastogram: a novel method to visualize local rigid body rotation under quasi-static compression

    NASA Astrophysics Data System (ADS)

    Sowmiya, C.; Kothawala, Ali Arshad; Thittai, Arun K.

    2016-04-01

    During manual palpation of breast masses, the perception of its stiffness and slipperiness are the two commonly used information by the physician. In order to reliably and quantitatively obtain this information several non-invasive elastography techniques have been developed that seek to provide an image of the underlying mechanical properties, mostly stiffness-related. Very few approaches have visualized the "slip" at the lesion-background boundary that only occurs for a loosely-bonded benign lesion. It has been shown that axial-shear strain distribution provides information about underlying slip. One such feature, referred to as "fill-in" was interpreted as a surrogate of the rotation undergone by an asymmetrically-oriented-loosely bonded-benign-lesion under quasi-static compression. However, imaging and direct visualization of the rotation itself has not been addressed yet. In order to accomplish this, the quality of lateral displacement estimation needs to be improved. In this simulation study, we utilize spatial compounding approach and assess the feasibility to obtain good quality rotation elastogram. The angular axial and lateral displacement estimates were obtained at different insonification angles from a phantom containing an elliptical inclusion oriented at 45°, subjected to 1% compression from the top. A multilevel 2D-block matching algorithm was used for displacement tracking and 2D-least square compounding of angular axial and lateral displacement estimates was employed. By varying the maximum steering angle and incremental angle, the improvement in the lateral motion tracking accuracy and its effects on the quality of rotational elastogram were evaluated. Results demonstrate significantly-improved rotation elastogram using this technique.

  5. Regular and chaotic motions in applied dynamics of a rigid body.

    PubMed

    Beletskii, V. V.; Pivovarov, M. L.; Starostin, E. L.

    1996-06-01

    Periodic and regular motions, having a predictable functioning mode, play an important role in many problems of dynamics. The achievements of mathematics and mechanics (beginning with Poincare) have made it possible to establish that such motion modes, generally speaking, are local and form "islands" of regularity in a "chaotic sea" of essentially unpredictable trajectories. The development of computer techniques together with theoretical investigations makes it possible to study the global structure of the phase space of many problems having applied significance. A review of a number of such problems, considered by the authors in the past four or five years, is given in this paper. These include orientation and rotation problems of artificial and natural celestial bodies and the problem of controlling the motion of a locomotion robot. The structure of phase space is investigated for these problems. The phase trajectories of the motion are constructed by a numerical implementation of the Poincare point map method. Distinctions are made between regular (or resonance), quasiregular (or conditionally periodic), and chaotic trajectories. The evolution of the phase picture as the parameters are varied is investigated. A large number of "phase portraits" gives a notion of the arrangement and size of the stability islands in the "sea" of chaotic motions, about the appearance and disappearance of these islands as the parameters are varied, etc. (c) 1996 American Institute of Physics.

  6. Arterial Mechanical Motion Estimation Based on a Semi-Rigid Body Deformation Approach

    PubMed Central

    Guzman, Pablo; Hamarneh, Ghassan; Ros, Rafael; Ros, Eduardo

    2014-01-01

    Arterial motion estimation in ultrasound (US) sequences is a hard task due to noise and discontinuities in the signal derived from US artifacts. Characterizing the mechanical properties of the artery is a promising novel imaging technique to diagnose various cardiovascular pathologies and a new way of obtaining relevant clinical information, such as determining the absence of dicrotic peak, estimating the Augmentation Index (AIx), the arterial pressure or the arterial stiffness. One of the advantages of using US imaging is the non-invasive nature of the technique unlike Intra Vascular Ultra Sound (IVUS) or angiography invasive techniques, plus the relative low cost of the US units. In this paper, we propose a semi rigid deformable method based on Soft Bodies dynamics realized by a hybrid motion approach based on cross-correlation and optical flow methods to quantify the elasticity of the artery. We evaluate and compare different techniques (for instance optical flow methods) on which our approach is based. The goal of this comparative study is to identify the best model to be used and the impact of the accuracy of these different stages in the proposed method. To this end, an exhaustive assessment has been conducted in order to decide which model is the most appropriate for registering the variation of the arterial diameter over time. Our experiments involved a total of 1620 evaluations within nine simulated sequences of 84 frames each and the estimation of four error metrics. We conclude that our proposed approach obtains approximately 2.5 times higher accuracy than conventional state-of-the-art techniques. PMID:24871987

  7. Rigid-body rotation of an electron cloud in divergent magnetic fields

    NASA Astrophysics Data System (ADS)

    Fruchtman, A.; Gueroult, R.; Fisch, N. J.

    2013-07-01

    For a given voltage across a divergent poloidal magnetic field, two electric potential distributions, each supported by a rigid-rotor electron cloud rotating with a different frequency, are found analytically. The two rotation frequencies correspond to the slow and fast rotation frequencies known in uniform plasma. Due to the centrifugal force, the equipotential surfaces, that correspond to the two electric potential distributions, diverge more than the magnetic surfaces do, the equipotential surfaces in the fast mode diverge largely in particular. The departure of the equipotential surfaces from the magnetic field surfaces may have a significant focusing effect on the ions accelerated by the electric field. The focusing effect could be important for laboratory plasma accelerators as well as for collimation of astrophysical jets.

  8. An integral equation formulation for rigid bodies in Stokes flow in three dimensions

    NASA Astrophysics Data System (ADS)

    Corona, Eduardo; Greengard, Leslie; Rachh, Manas; Veerapaneni, Shravan

    2017-03-01

    We present a new derivation of a boundary integral equation (BIE) for simulating the three-dimensional dynamics of arbitrarily-shaped rigid particles of genus zero immersed in a Stokes fluid, on which are prescribed forces and torques. Our method is based on a single-layer representation and leads to a simple second-kind integral equation. It avoids the use of auxiliary sources within each particle that play a role in some classical formulations. We use a spectrally accurate quadrature scheme to evaluate the corresponding layer potentials, so that only a small number of spatial discretization points per particle are required. The resulting discrete sums are computed in O (n) time, where n denotes the number of particles, using the fast multipole method (FMM). The particle positions and orientations are updated by a high-order time-stepping scheme. We illustrate the accuracy, conditioning and scaling of our solvers with several numerical examples.

  9. Chrono: A Parallel Physics Library for Rigid-Body, Flexible-Body, and Fluid Dynamics

    DTIC Science & Technology

    2013-08-01

    and memory hierarchy associated with GPUs. Today, an Nvidia GPU has close to seven billion transistors. Priced at about $6000, an Nvidia Kepler K20x...This section describes a validation effort in which experi- mental results were compared to simulation results obtained from Chrono::Engine. To this...used to set up a corre- sponding simulation to match the experimental results . For more detail, see [17]. UNCLASSIFIED 6 Copyright c© 2013 by ASME

  10. Flutter Instability of a Fluid-Conveying Fluid-Immersed Pipe Affixed to a Rigid Body

    DTIC Science & Technology

    2011-01-01

    have also been studied. The cantilever (Bourrieres, 1939; Gregory and Paı̈doussis, 1966) and pinned–pinned (Ashley and Haviland , 1950) conditions form...acknowledged. References Ashley, H., Haviland , G., 1950. Bending vibrations of a pipeline containing fluid. Journal of Applied Mechanics 17, 229–232. Bhat, R.B

  11. A discrete momentum-conserving explicit algorithm for rigid body dynamics analysis

    NASA Technical Reports Server (NTRS)

    Park, K. C.; Chiou, J. C.

    1993-01-01

    A discrete momentum-conserving explicit time integration is presented. The accurate feature and simplicity of the present algorithm are realized by a mid-point implicit formula for integrating the Euler parameters and a second-order discrete momentum-conserving form of the central difference algorithm, respectively. The accuracy and robustness of the algorithm is demonstrated by example problems which exhibit large overall rigid motions under holonomic constraints.

  12. Comparison of methods for developing the dynamics of rigid-body systems

    NASA Technical Reports Server (NTRS)

    Ju, M. S.; Mansour, J. M.

    1989-01-01

    Several approaches for developing the equations of motion for a three-degree-of-freedom PUMA robot were compared on the basis of computational efficiency (i.e., the number of additions, subtractions, multiplications, and divisions). Of particular interest was the investigation of the use of computer algebra as a tool for developing the equations of motion. Three approaches were implemented algebraically: Lagrange's method, Kane's method, and Wittenburg's method. Each formulation was developed in absolute and relative coordinates. These six cases were compared to each other and to a recursive numerical formulation. The results showed that all of the formulations implemented algebraically required fewer calculations than the recursive numerical algorithm. The algebraic formulations required fewer calculations in absolute coordinates than in relative coordinates. Each of the algebraic formulations could be simplified, using patterns from Kane's method, to yield the same number of calculations in a given coordinate system.

  13. A parametric study of the nonlinear dynamics and sensitivity of a beam-rigid body microgyroscope

    NASA Astrophysics Data System (ADS)

    Lajimi, S. A. M.; Heppler, G. R.; Abdel-Rahman, E. M.

    2017-09-01

    The nonlinear dynamical features of a gyroscopic system manifesting in a rotation rate sensor are presented. A computational shooting method and Floquet multipliers are used to characterize the response. Response characteristics are demonstrated and studied by generating various frequency-response plots, force-response curves, time-history plots, and phase-portraits. The effects of varying the DC bias voltages, the AC drive-voltage and drive-frequency, and the quality factors on the system response are studied in detail. The advantages of operating in the nonlinear regime are shown to appear in larger bandwidth and higher sensitivity.

  14. Correcting a Widespread Error concerning the Angular Velocity of a Rotating Rigid Body.

    ERIC Educational Resources Information Center

    Leubner, C.

    1981-01-01

    Since many texts use an incorrect argument in obtaining the instantaneous velocity of a rotating body, a correct and concise derivation of this quantity for a rather general case is given. (Author/SK)

  15. The Discrete Moser-Veselov Algorithm for the Free Rigid Body

    DTIC Science & Technology

    2007-11-02

    Z. & Krogstad, S. (2002), On enumeration problems in Lie–Butcher theory, Report in informatics, Institutt for informatikk, University of Bergen, Norway. To appear in Future Generation Computer Systems , Special issue.

  16. An efficient conservative cut-cell method for rigid bodies interacting with viscous compressible flows

    NASA Astrophysics Data System (ADS)

    Schneiders, Lennart; Günther, Claudia; Meinke, Matthias; Schröder, Wolfgang

    2016-04-01

    A Cartesian cut-cell method for viscous flows interacting with freely moving boundaries is presented. The method enables a sharp resolution of the embedded boundaries and strictly conserves mass, momentum, and energy. A new explicit Runge-Kutta scheme (PC-RK) is introduced by which the overall computational time is reduced by a factor of up to 2.5. The new scheme is a predictor-corrector type reformulation of a popular class of Runge-Kutta methods which substantially reduces the computational effort for tracking the moving boundaries and subsequently reinitializing the solver impairing neither stability nor accuracy. The structural motion is computed by an implicit scheme with good stability properties due to a strong-coupling strategy and the conservative discretization of the flow solver at the material interfaces. A new formulation for the treatment of small cut cells is proposed with high accuracy and robustness for arbitrary geometries based on a weighted Taylor-series approach solved via singular-value decomposition. The efficiency and the accuracy of the new method are demonstrated for several three-dimensional cases of laminar and turbulent particulate flow. It is shown that the new method remains fully conservative even for large displacements of the boundaries leading to a fast convergence of the fluid-solid coupling while spurious force oscillations inherent to this class of methods are effectively suppressed. The results substantiate the good stability and accuracy properties of the scheme even on relatively coarse meshes.

  17. Thermodynamic, diffusional, and structural anomalies in rigid-body water models.

    PubMed

    Agarwal, Manish; Alam, Mohammad Parvez; Chakravarty, Charusita

    2011-06-02

    Structural, density, entropy, and diffusivity anomalies of the TIP4P/2005 model of water are mapped out over a wide range of densities and temperatures. The locus of temperatures of maximum density (TMD) for this model is very close to the experimental TMD locus for temperatures between 250 and 275 K. Four different water models (mTIP3P, TIP4P, TIP5P, and SPC/E) are compared with the TIP4P/2005 model in terms of their anomalous behavior. For all the water models, the density regimes for anomalous behavior are bounded by a low-density limit at around 0.85-0.90 g cm(-3) and a high-density limit at about 1.10-1.15 g cm(-3). The onset temperatures of the density anomaly in the various models show a much greater variation, ranging from 202 K for mTIP3P to 289 K for TIP5P. The order maps for the various water models are qualitatively very similar with the structurally anomalous regions almost superimposable in the q(tet)-τ plane. Comparison of the phase diagrams of water models with the region of liquid-state anomalies shows that the crystalline phases are much more sensitive to the choice of water models than the liquid state anomalies; for example, SPC/E and TIP4P/2005 show qualitatively similar liquid state anomalies but very different phase diagrams. The anomalies in the liquid in all the models occur at much lower pressures than those at which the melting line changes from negative to positive slope. The results in this study demonstrate several aspects of structure-entropy-diffusivity relationships of water models that can be compared with experiment and used to develop better atomistic and coarse-grained models for water.

  18. Vehicle Concept Model Abstractions For Integrated Geometric, Inertial ,Rigid Body, Powertrain and FE Analysis

    DTIC Science & Technology

    2011-06-17

    2 The nomenclature “simplified model” has also been applied to attribute- based FEMs. We avoid this terminology ...Matt Castanier; Gary Osborne; Glen Prater; Rostyslav Lesiv 5d. PROJECT NUMBER 5e. TASK NUMBER 5f. WORK UNIT NUMBER 7. PERFORMING ORGANIZATION ...NAME(S) AND ADDRESS(ES) University of Louisville,Louisville,KY,40208 8. PERFORMING ORGANIZATION REPORT NUMBER ; #21933 9. SPONSORING/MONITORING

  19. Vehicle Concept Model Abstractions for Integrated Geometric, Inertial, Rigid Body, Powertrain, and FE Analysis

    DTIC Science & Technology

    2011-01-01

    including abstractions specific to 2 The nomenclature “simplified model” has also been...applied to attribute- based FEMs. We avoid this terminology because these models, while small in terms of element count, involve modeling decisions...TASK NUMBER 5f. WORK UNIT NUMBER 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) U.S. Army Research, Development and Engineering Command (RDECOM

  20. Kh. A. Rakhmatulin's scientific legacy in the field of mechanics of deformable rigid bodies

    NASA Astrophysics Data System (ADS)

    Goldstein, R. V.; Dem'yanov, Yu. A.; Nikitin, L. V.; Smirnov, N. N.; Shemyakin, E. I.

    2010-02-01

    Kh. A. Rakhmatulin's scientific activity was aimed at solving the most important scientific and technical problems encountered by the country. Khalil Akhmetovich was a unique combination of a theorist and an experimenter, an engineer and an inventor, a talented teacher and a scientific research manager. He fruitfully worked in mechanics of deformable solids (the corresponding results are surveyed in the present paper) as well as in fluid mechanics (as described in detail in the journal [1] dedicated to his memory).

  1. Rigid-body rotation of an electron cloud in divergent magnetic fields

    DOE PAGES

    Fruchtman, A.; Gueroult, R.; Fisch, N. J.

    2013-07-10

    For a given voltage across a divergent poloidal magnetic field, two electric potential distributions, each supported by a rigid-rotor electron cloud rotating with a different frequency, are found analytically. The two rotation frequencies correspond to the slow and fast rotation frequencies known in uniform plasma. Due to the centrifugal force, the equipotential surfaces, that correspond to the two electric potential distributions, diverge more than the magnetic surfaces do, the equipotential surfaces in the fast mode diverge largely in particular. The departure of the equipotential surfaces from the magnetic field surfaces may have a significant focusing effect on the ions acceleratedmore » by the electric field. Furthermore, the focusing effect could be important for laboratory plasma accelerators as well as for collimation of astrophysical jets.« less

  2. Rigid-body rotation of an electron cloud in divergent magnetic fields

    SciTech Connect

    Fruchtman, A.; Gueroult, R.; Fisch, N. J.

    2013-07-10

    For a given voltage across a divergent poloidal magnetic field, two electric potential distributions, each supported by a rigid-rotor electron cloud rotating with a different frequency, are found analytically. The two rotation frequencies correspond to the slow and fast rotation frequencies known in uniform plasma. Due to the centrifugal force, the equipotential surfaces, that correspond to the two electric potential distributions, diverge more than the magnetic surfaces do, the equipotential surfaces in the fast mode diverge largely in particular. The departure of the equipotential surfaces from the magnetic field surfaces may have a significant focusing effect on the ions accelerated by the electric field. Furthermore, the focusing effect could be important for laboratory plasma accelerators as well as for collimation of astrophysical jets.

  3. Rigid-body rotation of an electron cloud in divergent magnetic fields

    SciTech Connect

    Fruchtman, A.; Gueroult, R.; Fisch, N. J.

    2013-07-15

    For a given voltage across a divergent poloidal magnetic field, two electric potential distributions, each supported by a rigid-rotor electron cloud rotating with a different frequency, are found analytically. The two rotation frequencies correspond to the slow and fast rotation frequencies known in uniform plasma. Due to the centrifugal force, the equipotential surfaces, that correspond to the two electric potential distributions, diverge more than the magnetic surfaces do, the equipotential surfaces in the fast mode diverge largely in particular. The departure of the equipotential surfaces from the magnetic field surfaces may have a significant focusing effect on the ions accelerated by the electric field. The focusing effect could be important for laboratory plasma accelerators as well as for collimation of astrophysical jets.

  4. Rationalizing foot and ankle measurements to conform to a rigid body model.

    PubMed

    Al-Homidan, Suliman; Fletcher, Roger

    2006-04-01

    Accurate estimation of the in vivo locations of skeletal landmarks plays an integral role in several biomechanical research techniques. Because of rounding errors caused by instruments or skin movement, the data obtained through cinematography are usually not accurate and rise to a distance matrix which, because of the data errors, may not be Euclidean. The aim of this paper is to find the best Euclidean distance matrix (EDM) that approximates the distance matrix and then, an accurate estimation of the locations of skeletal landmarks. A useful scheme for parametrizing an orthogonal matrix is also described.

  5. Automatic registration of satellite imagery

    NASA Technical Reports Server (NTRS)

    Fonseca, Leila M. G.; Costa, Max H. M.; Manjunath, B. S.; Kenney, C.

    1997-01-01

    Image registration is one of the basic image processing operations in remote sensing. With the increase in the number of images collected every day from different sensors, automated registration of multi-sensor/multi-spectral images has become an important issue. A wide range of registration techniques has been developed for many different types of applications and data. The objective of this paper is to present an automatic registration algorithm which uses a multiresolution analysis procedure based upon the wavelet transform. The procedure is completely automatic and relies on the grey level information content of the images and their local wavelet transform modulus maxima. The registration algorithm is very simple and easy to apply because it needs basically one parameter. We have obtained very encouraging results on test data sets from the TM and SPOT sensor images of forest, urban and agricultural areas.

  6. Automatic design of magazine covers

    NASA Astrophysics Data System (ADS)

    Jahanian, Ali; Liu, Jerry; Tretter, Daniel R.; Lin, Qian; Damera-Venkata, Niranjan; O'Brien-Strain, Eamonn; Lee, Seungyon; Fan, Jian; Allebach, Jan P.

    2012-03-01

    In this paper, we propose a system for automatic design of magazine covers that quantifies a number of concepts from art and aesthetics. Our solution to automatic design of this type of media has been shaped by input from professional designers, magazine art directors and editorial boards, and journalists. Consequently, a number of principles in design and rules in designing magazine covers are delineated. Several techniques are derived and employed in order to quantify and implement these principles and rules in the format of a software framework. At this stage, our framework divides the task of design into three main modules: layout of magazine cover elements, choice of color for masthead and cover lines, and typography of cover lines. Feedback from professional designers on our designs suggests that our results are congruent with their intuition.

  7. Automatically scramming nuclear reactor system

    DOEpatents

    Ougouag, Abderrafi M.; Schultz, Richard R.; Terry, William K.

    2004-10-12

    An automatically scramming nuclear reactor system. One embodiment comprises a core having a coolant inlet end and a coolant outlet end. A cooling system operatively associated with the core provides coolant to the coolant inlet end and removes heated coolant from the coolant outlet end, thus maintaining a pressure differential therebetween during a normal operating condition of the nuclear reactor system. A guide tube is positioned within the core with a first end of the guide tube in fluid communication with the coolant inlet end of the core, and a second end of the guide tube in fluid communication with the coolant outlet end of the core. A control element is positioned within the guide tube and is movable therein between upper and lower positions, and automatically falls under the action of gravity to the lower position when the pressure differential drops below a safe pressure differential.

  8. Automatic translation among spoken languages

    NASA Astrophysics Data System (ADS)

    Walter, Sharon M.; Costigan, Kelly

    1994-02-01

    The Machine Aided Voice Translation (MAVT) system was developed in response to the shortage of experienced military field interrogators with both foreign language proficiency and interrogation skills. Combining speech recognition, machine translation, and speech generation technologies, the MAVT accepts an interrogator's spoken English question and translates it into spoken Spanish. The spoken Spanish response of the potential informant can then be translated into spoken English. Potential military and civilian applications for automatic spoken language translation technology are discussed in this paper.

  9. How CBO Estimates Automatic Stabilizers

    DTIC Science & Technology

    2015-11-01

    Pamela Green , Kurt Seibert, Joshua Shakin, and Robert Stewart for technical assistance. The authors also thank Leah Loversky for outstanding research...ANSI Std Z39-18 Abstract Federal receipts and outlays regularly respond to cyclical movements in the economy. When the economy is operating...Those “automatic stabilizers” thus tend to dampen the size of cyclical movements in the economy, by supporting or restraining private spending. (The

  10. Automatically-Programed Machine Tools

    NASA Technical Reports Server (NTRS)

    Purves, L.; Clerman, N.

    1985-01-01

    Software produces cutter location files for numerically-controlled machine tools. APT, acronym for Automatically Programed Tools, is among most widely used software systems for computerized machine tools. APT developed for explicit purpose of providing effective software system for programing NC machine tools. APT system includes specification of APT programing language and language processor, which executes APT statements and generates NC machine-tool motions specified by APT statements.

  11. Automatic computation of transfer functions

    DOEpatents

    Atcitty, Stanley; Watson, Luke Dale

    2015-04-14

    Technologies pertaining to the automatic computation of transfer functions for a physical system are described herein. The physical system is one of an electrical system, a mechanical system, an electromechanical system, an electrochemical system, or an electromagnetic system. A netlist in the form of a matrix comprises data that is indicative of elements in the physical system, values for the elements in the physical system, and structure of the physical system. Transfer functions for the physical system are computed based upon the netlist.

  12. Attention, Automaticity and Priority Learning

    DTIC Science & Technology

    1991-01-01

    paradiams is taken to indicate that processing remains under attentional control. This paper proposes a priority learning mechanism to model the...effects of practice and the development of automaticity, in visual search tasks. A connectionist simulation model implements this learning algorithm. Five...reliable finding from varied mapping studies is proposes a priority learning mechanism to model the effects of that reaction time increases roughly

  13. Automatic Home Nursing Activity Recommendation

    PubMed Central

    Luo, Gang; Tang, Chunqiang

    2009-01-01

    The rapid deployment of Web-based, consumer-centric electronic medical records (CEMRs) is an important trend in healthcare. In this paper, we incorporate nursing knowledge into CEMR so that it can automatically recommend home nursing activities (HNAs). Those more complex HNAs are made clickable for users to find detailed implementation procedures. We demonstrate the effectiveness of our techniques using USMLE medical exam cases. PMID:20351888

  14. Automatic translation among spoken languages

    NASA Technical Reports Server (NTRS)

    Walter, Sharon M.; Costigan, Kelly

    1994-01-01

    The Machine Aided Voice Translation (MAVT) system was developed in response to the shortage of experienced military field interrogators with both foreign language proficiency and interrogation skills. Combining speech recognition, machine translation, and speech generation technologies, the MAVT accepts an interrogator's spoken English question and translates it into spoken Spanish. The spoken Spanish response of the potential informant can then be translated into spoken English. Potential military and civilian applications for automatic spoken language translation technology are discussed in this paper.

  15. Automatic noise limiter-blanker

    NASA Technical Reports Server (NTRS)

    Burhans, R. W.

    1976-01-01

    A blanker system that may be used with audio noise limiters or automatic noise limiters was described. The system employs a pair of silicon diodes and two RC filters connected across the feedback impedance of an operational amplifier so as to counteract impulse noise interference caused by local spherics activity or 60 Hz harmonics radiated from ac motor control systems. The following information is given: circuit diagram and description, operating details, evaluation, discussion of other noise blanking methods.

  16. Group Dynamics in Automatic Imitation

    PubMed Central

    Wilson, Neil; Reddy, Geetha; Catmur, Caroline

    2016-01-01

    Imitation–matching the configural body movements of another individual–plays a crucial part in social interaction. We investigated whether automatic imitation is not only influenced by who we imitate (ingroup vs. outgroup member) but also by the nature of an expected interaction situation (competitive vs. cooperative). In line with assumptions from Social Identity Theory), we predicted that both social group membership and the expected situation impact on the level of automatic imitation. We adopted a 2 (group membership target: ingroup, outgroup) x 2 (situation: cooperative, competitive) design. The dependent variable was the degree to which participants imitated the target in a reaction time automatic imitation task. 99 female students from two British Universities participated. We found a significant two-way interaction on the imitation effect. When interacting in expectation of cooperation, imitation was stronger for an ingroup target compared to an outgroup target. However, this was not the case in the competitive condition where imitation did not differ between ingroup and outgroup target. This demonstrates that the goal structure of an expected interaction will determine the extent to which intergroup relations influence imitation, supporting a social identity approach. PMID:27657926

  17. Automatic Synthesis Imaging with Difmap

    NASA Astrophysics Data System (ADS)

    Pearson, T. J.; Shepherd, M. C.; Taylor, G. B.; Myers, S. T.

    1994-12-01

    Difmap is a new interactive program for synthesis imaging. It includes data display, data editing, self-calibration, imaging, deconvolution, and model-fitting. The program can handle continuum, spectral-line, and polarization data from connected-element and very-long-baseline interferometer arrays. The program is written in ANSI C and runs on UNIX workstations. We describe the operation of the program with example data sets from the Very Large Array, the global VLBI network, and the Owens Valley Millimeter Array. We have developed Difmap scripts for automatic mapping and self-calibration of both VLA and VLBI data. We describe the strategies adopted for choosing the imaging, deconvolution, and self-calibration parameters, and show how these automatic scripts have made possible the rapid imaging of several hundred sources in the Caltech--Jodrell Bank VLBI surveys (CJ1 and CJ2) and several thousand sources in a VLA search for gravitational lenses (CLASS). Other images made with automatic mapping in Difmap are presented at this meeting by Fassnacht et al., Myers et al., and Taylor et al.

  18. Automatic tracking sensor camera system

    NASA Astrophysics Data System (ADS)

    Tsuda, Takao; Kato, Daiichiro; Ishikawa, Akio; Inoue, Seiki

    2001-04-01

    We are developing a sensor camera system for automatically tracking and determining the positions of subjects moving in three-dimensions. The system is intended to operate even within areas as large as soccer fields. The system measures the 3D coordinates of the object while driving the pan and tilt movements of camera heads, and the degree of zoom of the lenses. Its principal feature is that it automatically zooms in as the object moves farther away and out as the object moves closer. This maintains the area of the object as a fixed position of the image. This feature makes stable detection by the image processing possible. We are planning to use the system to detect the position of a soccer ball during a soccer game. In this paper, we describe the configuration of the developing automatic tracking sensor camera system. We then give an analysis of the movements of the ball within images of games, the results of experiments on method of image processing used to detect the ball, and the results of other experiments to verify the accuracy of an experimental system. These results show that the system is sufficiently accurate in terms of obtaining positions in three-dimensions.

  19. Unification of automatic target tracking and automatic target recognition

    NASA Astrophysics Data System (ADS)

    Schachter, Bruce J.

    2014-06-01

    The subject being addressed is how an automatic target tracker (ATT) and an automatic target recognizer (ATR) can be fused together so tightly and so well that their distinctiveness becomes lost in the merger. This has historically not been the case outside of biology and a few academic papers. The biological model of ATT∪ATR arises from dynamic patterns of activity distributed across many neural circuits and structures (including retina). The information that the brain receives from the eyes is "old news" at the time that it receives it. The eyes and brain forecast a tracked object's future position, rather than relying on received retinal position. Anticipation of the next moment - building up a consistent perception - is accomplished under difficult conditions: motion (eyes, head, body, scene background, target) and processing limitations (neural noise, delays, eye jitter, distractions). Not only does the human vision system surmount these problems, but it has innate mechanisms to exploit motion in support of target detection and classification. Biological vision doesn't normally operate on snapshots. Feature extraction, detection and recognition are spatiotemporal. When vision is viewed as a spatiotemporal process, target detection, recognition, tracking, event detection and activity recognition, do not seem as distinct as they are in current ATT and ATR designs. They appear as similar mechanism taking place at varying time scales. A framework is provided for unifying ATT and ATR.

  20. The Automaticity of Social Life

    PubMed Central

    Bargh, John A.; Williams, Erin L.

    2008-01-01

    Much of social life is experienced through mental processes that are not intended and about which one is fairly oblivious. These processes are automatically triggered by features of the immediate social environment, such as the group memberships of other people, the qualities of their behavior, and features of social situations (e.g., norms, one's relative power). Recent research has shown these nonconscious influences to extend beyond the perception and interpretation of the social world to the actual guidance, over extended time periods, of one's important goal pursuits and social interactions. PMID:18568084

  1. Automatic interpretation of digital maps

    NASA Astrophysics Data System (ADS)

    Walter, Volker; Luo, Fen

    In the past, the availability and/or the acquisition of spatial data were often the main problems of the realization of spatial applications. Meanwhile this situation has changed: on one hand, comprehensive spatial datasets already exist and on the other hand, new sensor technologies have the ability to capture fast and with high quality large amounts of spatial data. More and more responsible for the increasing accessibility of spatial data are also collaborative mapping techniques which enable users to create maps by themselves and to make them available in the internet. However, the potential of this diversity of spatial data can only hardly be utilized. Especially maps in the internet are represented very often only with graphical elements and no explicit information about the map's scale, extension and content is available. Nevertheless, humans are able to extract this information and to interpret maps. For example, it is possible for a human to distinguish between rural and industrial areas only by looking at the objects' geometries. Furthermore, a human can easily identify and group map objects that belong together. Also the type, scale and extension of a map can be identified under certain conditions only by looking at the objects' geometries. All these examples can be subsumed under the term "map interpretation". In this paper it is discussed how map interpretation can be automated and how automatic map interpretation can be used in order to support other processes. The different kinds of automatic map interpretation are discussed and two approaches are shown in detail.

  2. Automatic temperature controlled retinal photocoagulation

    NASA Astrophysics Data System (ADS)

    Schlott, Kerstin; Koinzer, Stefan; Ptaszynski, Lars; Bever, Marco; Baade, Alex; Roider, Johann; Birngruber, Reginald; Brinkmann, Ralf

    2012-06-01

    Laser coagulation is a treatment method for many retinal diseases. Due to variations in fundus pigmentation and light scattering inside the eye globe, different lesion strengths are often achieved. The aim of this work is to realize an automatic feedback algorithm to generate desired lesion strengths by controlling the retinal temperature increase with the irradiation time. Optoacoustics afford non-invasive retinal temperature monitoring during laser treatment. A 75 ns/523 nm Q-switched Nd:YLF laser was used to excite the temperature-dependent pressure amplitudes, which were detected at the cornea by an ultrasonic transducer embedded in a contact lens. A 532 nm continuous wave Nd:YAG laser served for photocoagulation. The ED50 temperatures, for which the probability of ophthalmoscopically visible lesions after one hour in vivo in rabbits was 50%, varied from 63°C for 20 ms to 49°C for 400 ms. Arrhenius parameters were extracted as ΔE=273 J mol-1 and A=3.1044 s-1. Control algorithms for mild and strong lesions were developed, which led to average lesion diameters of 162+/-34 μm and 189+/-34 μm, respectively. It could be demonstrated that the sizes of the automatically controlled lesions were widely independent of the treatment laser power and the retinal pigmentation.

  3. Automatic precision measurement of spectrograms.

    PubMed

    Palmer, B A; Sansonetti, C J; Andrew, K L

    1978-08-01

    A fully automatic comparator has been designed and implemented to determine precision wavelengths from high-resolution spectrograms. The accuracy attained is superior to that of an experienced operator using a semiautomatic comparator with a photoelectric setting device. The system consists of a comparator, slightly modified for simultaneous data acquisition from two parallel scans of the spectrogram, interfaced to a minicomputer. The software which controls the system embodies three innovations of special interest. (1) Data acquired from two parallel scans are compared and used to separate unknown from standard lines, to eliminate spurious lines, to identify blends of unknown with standard lines, to improve the accuracy of the measured positions, and to flag lines which require special examination. (2) Two classes of lines are automatically recognized and appropriate line finding methods are applied to each. This provides precision measurement for both simple and complex line profiles. (3) Wavelength determination using a least-squares fitted grating equation is supported in addition to polynomial interpolation. This is most useful in spectral regions with sparsely distributed standards. The principles and implementation of these techniques are fully described.

  4. Automatic Computer Mapping of Terrain

    NASA Technical Reports Server (NTRS)

    Smedes, H. W.

    1971-01-01

    Computer processing of 17 wavelength bands of visible, reflective infrared, and thermal infrared scanner spectrometer data, and of three wavelength bands derived from color aerial film has resulted in successful automatic computer mapping of eight or more terrain classes in a Yellowstone National Park test site. The tests involved: (1) supervised and non-supervised computer programs; (2) special preprocessing of the scanner data to reduce computer processing time and cost, and improve the accuracy; and (3) studies of the effectiveness of the proposed Earth Resources Technology Satellite (ERTS) data channels in the automatic mapping of the same terrain, based on simulations, using the same set of scanner data. The following terrain classes have been mapped with greater than 80 percent accuracy in a 12-square-mile area with 1,800 feet of relief; (1) bedrock exposures, (2) vegetated rock rubble, (3) talus, (4) glacial kame meadow, (5) glacial till meadow, (6) forest, (7) bog, and (8) water. In addition, shadows of clouds and cliffs are depicted, but were greatly reduced by using preprocessing techniques.

  5. Automatic temperature controlled retinal photocoagulation.

    PubMed

    Schlott, Kerstin; Koinzer, Stefan; Ptaszynski, Lars; Bever, Marco; Baade, Alex; Roider, Johann; Birngruber, Reginald; Brinkmann, Ralf

    2012-06-01

    Laser coagulation is a treatment method for many retinal diseases. Due to variations in fundus pigmentation and light scattering inside the eye globe, different lesion strengths are often achieved. The aim of this work is to realize an automatic feedback algorithm to generate desired lesion strengths by controlling the retinal temperature increase with the irradiation time. Optoacoustics afford non-invasive retinal temperature monitoring during laser treatment. A 75 ns/523 nm Q-switched Nd:YLF laser was used to excite the temperature-dependent pressure amplitudes, which were detected at the cornea by an ultrasonic transducer embedded in a contact lens. A 532 nm continuous wave Nd:YAG laser served for photocoagulation. The ED50 temperatures, for which the probability of ophthalmoscopically visible lesions after one hour in vivo in rabbits was 50%, varied from 63°C for 20 ms to 49°C for 400 ms. Arrhenius parameters were extracted as ΔE=273 J mol(-1) and A=3 x 10(44) s(-1). Control algorithms for mild and strong lesions were developed, which led to average lesion diameters of 162 ± 34 μm and 189 ± 34 μm, respectively. It could be demonstrated that the sizes of the automatically controlled lesions were widely independent of the treatment laser power and the retinal pigmentation.

  6. Automatic testing of speech recognition.

    PubMed

    Francart, Tom; Moonen, Marc; Wouters, Jan

    2009-02-01

    Speech reception tests are commonly administered by manually scoring the oral response of the subject. This requires a test supervisor to be continuously present. To avoid this, a subject can type the response, after which it can be scored automatically. However, spelling errors may then be counted as recognition errors, influencing the test results. We demonstrate an autocorrection approach based on two scoring algorithms to cope with spelling errors. The first algorithm deals with sentences and is based on word scores. The second algorithm deals with single words and is based on phoneme scores. Both algorithms were evaluated with a corpus of typed answers based on three different Dutch speech materials. The percentage of differences between automatic and manual scoring was determined, in addition to the mean difference in speech recognition threshold. The sentence correction algorithm performed at a higher accuracy than commonly obtained with these speech materials. The word correction algorithm performed better than the human operator. Both algorithms can be used in practice and allow speech reception tests with open set speech materials over the internet.

  7. Automatic referral to cardiac rehabilitation.

    PubMed

    Fischer, Jane P

    2008-01-01

    The pervasive negative impact of cardiovascular disease in the United States is well documented. Although advances have been made, the campaign to reduce the occurrence, progression, and mortality continues. Determining evidence-based data is only half the battle. Implementing new and updated clinical guidelines into daily practice is a challenging task. Cardiac rehabilitation is an example of a proven intervention whose benefit is hindered through erratic implementation. The American Association of Cardiovascular and Pulmonary Rehabilitation (AACVPR), the American College of Cardiology (ACC), and the American Heart Association (AHA) have responded to this problem by publishing the AACVPR/ACC/AHA 2007 Performance Measures on Cardiac Rehabilitation for Referral to and Delivery of Cardiac Rehabilitation/Secondary Prevention Services. This new national guideline recommends automatic referral to cardiac rehabilitation for every eligible patient (performance measure A-1). This article offers guidance for the initiation of an automatic referral system, including individualizing your protocol with regard to electronic or paper-based order entry structures.

  8. Automatic visible watermarking of images

    NASA Astrophysics Data System (ADS)

    Rao, A. Ravishankar; Braudaway, Gordon W.; Mintzer, Frederick C.

    1998-04-01

    Visible image watermarking has become an important and widely used technique to identify ownership and protect copyrights to images. A visible image watermark immediately identifies the owner of an image, and if properly constructed, can deter subsequent unscrupulous use of the image. The insertion of a visible watermark should satisfy two conflicting conditions: the intensity of the watermark should be strong enough to be perceptible, yet it should be light enough to be unobtrusive and not mar the beauty of the original image. Typically such an adjustment is made manually, and human intervention is required to set the intensity of the watermark at the right level. This is fine for a few images, but is unsuitable for a large collection of images. Thus, it is desirable to have a technique to automatically adjust the intensity of the watermark based on some underlying property of each image. This will allow a large number of images to be automatically watermarked, this increasing the throughput of the watermarking stage. In this paper we show that the measurement of image texture can be successfully used to automate the adjustment of watermark intensity. A linear regression model is used to predict subjective assessments of correct watermark intensity based on image texture measurements.

  9. Neologistic speech automatisms during complex partial seizures.

    PubMed

    Bell, W L; Horner, J; Logue, P; Radtke, R A

    1990-01-01

    There are no documented cases of seizures causing reiterative neologistic speech automatisms. We report an 18-year-old right-handed woman with stereotypic ictal speech automatisms characterized by phonemic jargon and reiterative neologisms. Video-EEG during the reiterative neologisms demonstrated rhythmic delta activity, which was most prominent in the left posterior temporal region. At surgery, there was an arteriovenous malformation impinging on the left supramarginal gyrus and the posterior portion of the superior temporal gyrus. Though intelligible speech automatisms can result from seizure foci in either hemisphere, neologistic speech automatisms may implicate a focus in the language-dominant hemisphere.

  10. ANPS - AUTOMATIC NETWORK PROGRAMMING SYSTEM

    NASA Technical Reports Server (NTRS)

    Schroer, B. J.

    1994-01-01

    Development of some of the space program's large simulation projects -- like the project which involves simulating the countdown sequence prior to spacecraft liftoff -- requires the support of automated tools and techniques. The number of preconditions which must be met for a successful spacecraft launch and the complexity of their interrelationship account for the difficulty of creating an accurate model of the countdown sequence. Researchers developed ANPS for the Nasa Marshall Space Flight Center to assist programmers attempting to model the pre-launch countdown sequence. Incorporating the elements of automatic programming as its foundation, ANPS aids the user in defining the problem and then automatically writes the appropriate simulation program in GPSS/PC code. The program's interactive user dialogue interface creates an internal problem specification file from user responses which includes the time line for the countdown sequence, the attributes for the individual activities which are part of a launch, and the dependent relationships between the activities. The program's automatic simulation code generator receives the file as input and selects appropriate macros from the library of software modules to generate the simulation code in the target language GPSS/PC. The user can recall the problem specification file for modification to effect any desired changes in the source code. ANPS is designed to write simulations for problems concerning the pre-launch activities of space vehicles and the operation of ground support equipment and has potential for use in developing network reliability models for hardware systems and subsystems. ANPS was developed in 1988 for use on IBM PC or compatible machines. The program requires at least 640 KB memory and one 360 KB disk drive, PC DOS Version 2.0 or above, and GPSS/PC System Version 2.0 from Minuteman Software. The program is written in Turbo Prolog Version 2.0. GPSS/PC is a trademark of Minuteman Software. Turbo Prolog

  11. Automatic force balance calibration system

    NASA Technical Reports Server (NTRS)

    Ferris, Alice T. (Inventor)

    1996-01-01

    A system for automatically calibrating force balances is provided. The invention uses a reference balance aligned with the balance being calibrated to provide superior accuracy while minimizing the time required to complete the calibration. The reference balance and the test balance are rigidly attached together with closely aligned moment centers. Loads placed on the system equally effect each balance, and the differences in the readings of the two balances can be used to generate the calibration matrix for the test balance. Since the accuracy of the test calibration is determined by the accuracy of the reference balance and current technology allows for reference balances to be calibrated to within .+-.0.05%, the entire system has an accuracy of a .+-.0.2%. The entire apparatus is relatively small and can be mounted on a movable base for easy transport between test locations. The system can also accept a wide variety of reference balances, thus allowing calibration under diverse load and size requirements.

  12. Automatic Nanodesign Using Evolutionary Techniques

    NASA Technical Reports Server (NTRS)

    Globus, Al; Saini, Subhash (Technical Monitor)

    1998-01-01

    Many problems associated with the development of nanotechnology require custom designed molecules. We use genetic graph software, a new development, to automatically evolve molecules of interest when only the requirements are known. Genetic graph software designs molecules, and potentially nanoelectronic circuits, given a fitness function that determines which of two molecules is better. A set of molecules, the first generation, is generated at random then tested with the fitness function, Subsequent generations are created by randomly choosing two parent molecules with a bias towards high scoring molecules, tearing each molecules in two at random, and mating parts from the mother and father to create two children. This procedure is repeated until a satisfactory molecule is found. An atom pair similarity test is currently used as the fitness function to evolve molecules similar to existing pharmaceuticals.

  13. Autoclass: An automatic classification system

    NASA Technical Reports Server (NTRS)

    Stutz, John; Cheeseman, Peter; Hanson, Robin

    1991-01-01

    The task of inferring a set of classes and class descriptions most likely to explain a given data set can be placed on a firm theoretical foundation using Bayesian statistics. Within this framework, and using various mathematical and algorithmic approximations, the AutoClass System searches for the most probable classifications, automatically choosing the number of classes and complexity of class descriptions. A simpler version of AutoClass has been applied to many large real data sets, has discovered new independently-verified phenomena, and has been released as a robust software package. Recent extensions allow attributes to be selectively correlated within particular classes, and allow classes to inherit, or share, model parameters through a class hierarchy. The mathematical foundations of AutoClass are summarized.

  14. Automatic inspection of leather surfaces

    NASA Astrophysics Data System (ADS)

    Poelzleitner, Wolfgang; Niel, Albert

    1994-10-01

    This paper describes the key elements of a system for detecting quality defects on leather surfaces. The inspection task must treat defects like scars, mite nests, warts, open fissures, healed scars, holes, pin holes, and fat folds. The industrial detection of these defects is difficult because of the large dimensions of the leather hides (2 m X 3 m), and the small dimensions of the defects (150 micrometers X 150 micrometers ). Pattern recognition approaches suffer from the fact that defects are hidden on an irregularly textured background, and can be hardly seen visually by human graders. We describe the methods tested for automatic classification using image processing, which include preprocessing, local feature description of texture elements, and final segmentation and grading of defects. We conclude with a statistical evaluation of the recognition error rate, and an outlook on the expected industrial performance.

  15. Automatic electronic fish tracking system

    NASA Technical Reports Server (NTRS)

    Osborne, P. W.; Hoffman, E.; Merriner, J. V.; Richards, C. E.; Lovelady, R. W.

    1976-01-01

    A newly developed electronic fish tracking system to automatically monitor the movements and migratory habits of fish is reported. The system is aimed particularly at studies of effects on fish life of industrial facilities which use rivers or lakes to dump their effluents. Location of fish is acquired by means of acoustic links from the fish to underwater Listening Stations, and by radio links which relay tracking information to a shore-based Data Base. Fish over 4 inches long may be tracked over a 5 x 5 mile area. The electronic fish tracking system provides the marine scientist with electronics which permit studies that were not practical in the past and which are cost-effective compared to manual methods.

  16. Automatic Mechetronic Wheel Light Device

    DOEpatents

    Khan, Mohammed John Fitzgerald

    2004-09-14

    A wheel lighting device for illuminating a wheel of a vehicle to increase safety and enhance aesthetics. The device produces the appearance of a "ring of light" on a vehicle's wheels as the vehicle moves. The "ring of light" can automatically change in color and/or brightness according to a vehicle's speed, acceleration, jerk, selection of transmission gears, and/or engine speed. The device provides auxiliary indicator lights by producing light in conjunction with a vehicle's turn signals, hazard lights, alarm systems, and etc. The device comprises a combination of mechanical and electronic components and can be placed on the outer or inner surface of a wheel or made integral to a wheel or wheel cover. The device can be configured for all vehicle types, and is electrically powered by a vehicle's electrical system and/or battery.

  17. Automatic insulation resistance testing apparatus

    DOEpatents

    Wyant, Francis J.; Nowlen, Steven P.; Luker, Spencer M.

    2005-06-14

    An apparatus and method for automatic measurement of insulation resistances of a multi-conductor cable. In one embodiment of the invention, the apparatus comprises a power supply source, an input measuring means, an output measuring means, a plurality of input relay controlled contacts, a plurality of output relay controlled contacts, a relay controller and a computer. In another embodiment of the invention the apparatus comprises a power supply source, an input measuring means, an output measuring means, an input switching unit, an output switching unit and a control unit/data logger. Embodiments of the apparatus of the invention may also incorporate cable fire testing means. The apparatus and methods of the present invention use either voltage or current for input and output measured variables.

  18. Automatic communication signal monitoring system

    NASA Technical Reports Server (NTRS)

    Bernstein, A. J. (Inventor)

    1978-01-01

    A system is presented for automatic monitoring of a communication signal in the RF or IF spectrum utilizing a superheterodyne receiver technique with a VCO to select and sweep the frequency band of interest. A first memory is used to store one band sweep as a reference for continual comparison with subsequent band sweeps. Any deviation of a subsequent band sweep by more than a predetermined tolerance level produces an alarm signal which causes the band sweep data temporarily stored in one of two buffer memories to be transferred to long-term store while the other buffer memory is switched to its store mode to assume the task of temporarily storing subsequent band sweeps.

  19. Automatic thermal switch. [spacecraft applications

    NASA Technical Reports Server (NTRS)

    Cunningham, J. W.; Wing, L. D. (Inventor)

    1983-01-01

    An automatic thermal switch to control heat flow includes two thermally conductive plates and a thermally conductive switch saddle pivotally mounted to the first plate. A flexible heat carrier is connected between the switch saddle and the second plate. A phase-change power unit, including a piston coupled to the switch saddle, is in thermal contact with the first thermally conductive plate. A biasing element biases the switch saddle in a predetermined position with respect to the first plate. When the phase-change power unit is actuated by an increase in heat transmitted through the first place, the piston extends and causes the switch saddle to pivot, thereby varying the thermal conduction between the two plates through the switch saddle and flexible heat carrier. The biasing element, switch saddle, and piston can be arranged to provide either a normally closed or normally opened thermally conductive path between the two plates.

  20. Automatic AVHRR image navigation software

    NASA Technical Reports Server (NTRS)

    Baldwin, Dan; Emery, William

    1992-01-01

    This is the final report describing the work done on the project entitled Automatic AVHRR Image Navigation Software funded through NASA-Washington, award NAGW-3224, Account 153-7529. At the onset of this project, we had developed image navigation software capable of producing geo-registered images from AVHRR data. The registrations were highly accurate but required a priori knowledge of the spacecraft's axes alignment deviations, commonly known as attitude. The three angles needed to describe the attitude are called roll, pitch, and yaw, and are the components of the deviations in the along scan, along track and about center directions. The inclusion of the attitude corrections in the navigation software results in highly accurate georegistrations, however, the computation of the angles is very tedious and involves human interpretation for several steps. The technique also requires easily identifiable ground features which may not be available due to cloud cover or for ocean data. The current project was motivated by the need for a navigation system which was automatic and did not require human intervention or ground control points. The first step in creating such a system must be the ability to parameterize the spacecraft's attitude. The immediate goal of this project was to study the attitude fluctuations and determine if they displayed any systematic behavior which could be modeled or parameterized. We chose a period in 1991-1992 to study the attitude of the NOAA 11 spacecraft using data from the Tiros receiving station at the Colorado Center for Astrodynamic Research (CCAR) at the University of Colorado.

  1. Aided versus automatic target recognition

    NASA Astrophysics Data System (ADS)

    O'Hair, Mark A.; Purvis, Bradley D.; Brown, Jeff

    1997-06-01

    Automatic target recognition (ATR) algorithms have offered the promise of recognizing items of military importance over the past 20 years. It is the experience of the authors that greater ATR success would be possible if the ATR were used to 'aid' the human operator instead of automatically 'direct' the operator. ATRs have failed not due to their probability of detection versus false alarm rate, but to neglect of the human component. ATRs are designed to improve overall throughput by relieving the human operator of the need to perform repetitive tasks like scanning vast quantities of imagery for possible targets. ATRs are typically inserted prior to the operator and provide cues, which are then accepted or rejected. From our experience at three field exercises and a current operational deployment to the Bosnian theater, this is not the best way to get total system performance. The human operator makes decisions based on learning, history of past events, and surrounding contextual information. Loss of these factors by providing imagery, latent with symbolic cues on top of the original imagery, actually increases the workload of the operator. This paper covers the lessons learned from the field demonstrations and the operational deployment. The reconnaissance and intelligence community's primary use of an ATR should be to establish prioritized cues of potential targets for an operator to 'pull' from and to be able to 'send' targets identified by the operator for a 'second opinion.' The Army and Air Force are modifying their exploitation workstations over the next 18 months to use ATRs, which operate in this fashion. This will be the future architecture that ATRs for the reconnaissance and intelligence community should integrate into.

  2. Automatic toilet seat lowering apparatus

    DOEpatents

    Guerty, Harold G.

    1994-09-06

    A toilet seat lowering apparatus includes a housing defining an internal cavity for receiving water from the water supply line to the toilet holding tank. A descent delay assembly of the apparatus can include a stationary dam member and a rotating dam member for dividing the internal cavity into an inlet chamber and an outlet chamber and controlling the intake and evacuation of water in a delayed fashion. A descent initiator is activated when the internal cavity is filled with pressurized water and automatically begins the lowering of the toilet seat from its upright position, which lowering is also controlled by the descent delay assembly. In an alternative embodiment, the descent initiator and the descent delay assembly can be combined in a piston linked to the rotating dam member and provided with a water channel for creating a resisting pressure to the advancing piston and thereby slowing the associated descent of the toilet seat. A toilet seat lowering apparatus includes a housing defining an internal cavity for receiving water from the water supply line to the toilet holding tank. A descent delay assembly of the apparatus can include a stationary dam member and a rotating dam member for dividing the internal cavity into an inlet chamber and an outlet chamber and controlling the intake and evacuation of water in a delayed fashion. A descent initiator is activated when the internal cavity is filled with pressurized water and automatically begins the lowering of the toilet seat from its upright position, which lowering is also controlled by the descent delay assembly. In an alternative embodiment, the descent initiator and the descent delay assembly can be combined in a piston linked to the rotating dam member and provided with a water channel for creating a resisting pressure to the advancing piston and thereby slowing the associated descent of the toilet seat.

  3. Pattern Recognition For Automatic Visual Inspection

    NASA Astrophysics Data System (ADS)

    Fu, K. S.

    1982-11-01

    Three major approaches to pattern recognition, (1) template matching, (2) decision-theoretic approach, and (3) structural and syntactic approach, are briefly introduced. The application of these approaches to automatic visual inspection of manufactured products are then reviewed. A more general method for automatic visual inspection of IC chips is then proposed. Several practical examples are included for illustration.

  4. Integrating Automatic Genre Analysis into Digital Libraries.

    ERIC Educational Resources Information Center

    Rauber, Andreas; Muller-Kogler, Alexander

    With the number and types of documents in digital library systems increasing, tools for automatically organizing and presenting the content have to be found. While many approaches focus on topic-based organization and structuring, hardly any system incorporates automatic structural analysis and representation. Yet, genre information…

  5. Automatic Grading of Spreadsheet and Database Skills

    ERIC Educational Resources Information Center

    Kovacic, Zlatko J.; Green, John Steven

    2012-01-01

    Growing enrollment in distance education has increased student-to-lecturer ratios and, therefore, increased the workload of the lecturer. This growing enrollment has resulted in mounting efforts to develop automatic grading systems in an effort to reduce this workload. While research in the design and development of automatic grading systems has a…

  6. Automatic data editing: a brief introduction

    SciTech Connect

    Liepins, G.E.

    1982-01-01

    This paper briefly discusses the automatic data editing process: (1) check the data records for consistency, (2) analyze the inconsistent records to determine the inconsistent variables. It is stated that the application of automatic data editing is broad, and two specific examples are cited. One example, that of a vehicle maintenance data base is used to illustrate the process.

  7. Automatic Item Generation of Probability Word Problems

    ERIC Educational Resources Information Center

    Holling, Heinz; Bertling, Jonas P.; Zeuch, Nina

    2009-01-01

    Mathematical word problems represent a common item format for assessing student competencies. Automatic item generation (AIG) is an effective way of constructing many items with predictable difficulties, based on a set of predefined task parameters. The current study presents a framework for the automatic generation of probability word problems…

  8. Towards Multilingual Interoperability in Automatic Speech Recognition

    DTIC Science & Technology

    2000-08-01

    UNCLASSIFIED Defense Technical Information Center Compilation Part Notice ADP010388 TITLE: Towards Multilingual Interoperability in Automatic Speech...component part numbers comprise the compilation report: ADPO10378 thru ADPO10397 UNCLASSIFIED 69 TOWARDS MULTILINGUAL INTEROPERABILITY IN AUTOMATIC SPEECH...communication, we address multilingual interoperability (DARPA) [39, 5, 12, 40, 14, 43]. aspects in speech recognition. After giving a tentative

  9. Prospects for Automatic Recognition of Speech.

    ERIC Educational Resources Information Center

    Houde, Robert

    1979-01-01

    Originally part of a symposium on educational media for the deaf, the paper discusses problems with the development of technology permitting simultaneous automatic captioning of speech. It is concluded that success with a machine which will provide automatic recognition of speech is still many years in the future. (PHR)

  10. 47 CFR 87.219 - Automatic operations.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 5 2010-10-01 2010-10-01 false Automatic operations. 87.219 Section 87.219... Aeronautical Advisory Stations (Unicoms) § 87.219 Automatic operations. (a) A station operator need not be present when an automated unicom is in operation. (b) Unicoms operating in an automated mode must...

  11. Automatic Contour Tracking in Ultrasound Images

    ERIC Educational Resources Information Center

    Li, Min; Kambhamettu, Chandra; Stone, Maureen

    2005-01-01

    In this paper, a new automatic contour tracking system, EdgeTrak, for the ultrasound image sequences of human tongue is presented. The images are produced by a head and transducer support system (HATS). The noise and unrelated high-contrast edges in ultrasound images make it very difficult to automatically detect the correct tongue surfaces. In…

  12. An Experiment in Automatic Hierarchical Document Classification.

    ERIC Educational Resources Information Center

    Garland, Kathleen

    1983-01-01

    Describes method of automatic document classification in which documents classed as QA by Library of Congress classification system were clustered at six thresholds by keyword using single link technique. Automatically generated clusters were compared to Library of Congress subclasses, and partial classified hierarchy was formed. Twelve references…

  13. Automatic restart of complex irrigation systems

    SciTech Connect

    Werner, H.D.; Alcock, R.; DeBoer, D.W.; Olson, D.I. . Dept. of Agricultural Engineering)

    1992-05-01

    Automatic restart of irrigation systems under load management has the potential to maximize pumping time during off-peak hours. Existing automation technology ranges from time delay relays to more sophisticated control using computers together with weather data to optimize irrigation practices. Centrifugal pumps and water hammer concerns prevent automatic restart of common but often complex irrigation systems in South Dakota. The irrigator must manually prime the pump and control water hammer during pipeline pressurization. Methods to prime centrifugal pumps and control water hammer facilitate automatic restart after load management is released. Seven priming methods and three water hammer control methods were investigated. A sump pump and small vacuum pump were used to test two automatic prime and restart systems in the laboratory. A variable frequency phase converter was also used to automatically control water hammer during pipeline pressurization. Economical methods to safely prime and restart centrifugal pumps were discussed. The water hammer control methods safely pressurize the pipeline but require a higher initial investment. The automatic restart systems can be used to safely restart centrifugal pumps and control water hammer after load management is released. Based upon laboratory research and a technical review of available restart components, a computer software program was developed. The program assists customers in evaluating various restart options for automatic restarting of electric irrigation pumps. For further information on the software program, contact the South Dakota State University, Department of Agricultural Engineering.

  14. A neurocomputational model of automatic sequence production.

    PubMed

    Helie, Sebastien; Roeder, Jessica L; Vucovich, Lauren; Rünger, Dennis; Ashby, F Gregory

    2015-07-01

    Most behaviors unfold in time and include a sequence of submovements or cognitive activities. In addition, most behaviors are automatic and repeated daily throughout life. Yet, relatively little is known about the neurobiology of automatic sequence production. Past research suggests a gradual transfer from the associative striatum to the sensorimotor striatum, but a number of more recent studies challenge this role of the BG in automatic sequence production. In this article, we propose a new neurocomputational model of automatic sequence production in which the main role of the BG is to train cortical-cortical connections within the premotor areas that are responsible for automatic sequence production. The new model is used to simulate four different data sets from human and nonhuman animals, including (1) behavioral data (e.g., RTs), (2) electrophysiology data (e.g., single-neuron recordings), (3) macrostructure data (e.g., TMS), and (4) neurological circuit data (e.g., inactivation studies). We conclude with a comparison of the new model with existing models of automatic sequence production and discuss a possible new role for the BG in automaticity and its implication for Parkinson's disease.

  15. Actuator for automatic cruising system

    SciTech Connect

    Suzuki, K.

    1989-03-07

    An actuator for an automatic cruising system is described, comprising: a casing; a control shaft provided in the casing for rotational movement; a control motor for driving the control shaft; an input shaft; an electromagnetic clutch and a reduction gear which are provided between the control motor and the control shaft; and an external linkage mechanism operatively connected to the control shaft; wherein the reduction gear is a type of Ferguson's mechanical paradox gear having a pinion mounted on the input shaft always connected to the control motor; a planetary gear meshing with the pinion so as to revolve around the pinion; a static internal gear meshing with the planetary gear and connected with the electromagnetic clutch for movement to a position restricting rotation of the static internal gear; and a rotary internal gear fixed on the control shaft and meshed with the planetary gear, the rotary internal gear having a number of teeth slightly different from a number of teeth of the static internal gear; and the electromagnetic clutch has a tubular electromagnetic coil coaxially provided around the input shaft and an engaging means for engaging and disengaging with the static internal gear in accordance with on-off operation of the electromagnetic coil.

  16. Automatic transmission for motor vehicles

    SciTech Connect

    Miura, M.; Sakakibara, S.

    1989-06-27

    An automatic transmission for a motor vehicle is described, comprising: a transmission housing; a hydraulic torque converter having rotational axes, an input shaft, an output shaft and a direct coupling clutch for directly coupling the input shaft to the output shaft; an auxiliary transmission mechanism provided coaxially with the hydraulic torque converter and having an input shaft, an output shaft with an input end and an output end and an overdrive mechanism of planetary gear type having a reduction ratio smaller than 1, the input shaft and the output shaft of the auxiliary transmission being located close to and on the side of the hydraulic torque converter with respect to the auxiliary transmission, respectively, and being coupled with a planetary gear carrier and a ring gear of the overdrive mechanism, respectively, a one-way clutch being provided between the planetary gear carrier and a sun gear of the overdrive mechanism, a clutch being provided between the planetary gear carrier and a position radially and outwardly of the one-way clutch for engaging the disengaging the planetary carrier and the sun gear, a brake being provided between the transmission housing and the sun gear and positioned radially and outwardly of the clutch for controlling engagement of the sun gear with a stationary portion of the transmission housing, and the output end of the output shaft being disposed between the auxiliary transmission mechanism and the hydraulic torque converter.

  17. Automatic locking orthotic knee device

    NASA Technical Reports Server (NTRS)

    Weddendorf, Bruce C. (Inventor)

    1993-01-01

    An articulated tang in clevis joint for incorporation in newly manufactured conventional strap-on orthotic knee devices or for replacing such joints in conventional strap-on orthotic knee devices is discussed. The instant tang in clevis joint allows the user the freedom to extend and bend the knee normally when no load (weight) is applied to the knee and to automatically lock the knee when the user transfers weight to the knee, thus preventing a damaged knee from bending uncontrollably when weight is applied to the knee. The tang in clevis joint of the present invention includes first and second clevis plates, a tang assembly and a spacer plate secured between the clevis plates. Each clevis plate includes a bevelled serrated upper section. A bevelled shoe is secured to the tank in close proximity to the bevelled serrated upper section of the clevis plates. A coiled spring mounted within an oblong bore of the tang normally urges the shoes secured to the tang out of engagement with the serrated upper section of each clevic plate to allow rotation of the tang relative to the clevis plate. When weight is applied to the joint, the load compresses the coiled spring, the serrations on each clevis plate dig into the bevelled shoes secured to the tang to prevent relative movement between the tang and clevis plates. A shoulder is provided on the tang and the spacer plate to prevent overextension of the joint.

  18. Automatic segmentation of psoriasis lesions

    NASA Astrophysics Data System (ADS)

    Ning, Yang; Shi, Chenbo; Wang, Li; Shu, Chang

    2014-10-01

    The automatic segmentation of psoriatic lesions is widely researched these years. It is an important step in Computer-aid methods of calculating PASI for estimation of lesions. Currently those algorithms can only handle single erythema or only deal with scaling segmentation. In practice, scaling and erythema are often mixed together. In order to get the segmentation of lesions area - this paper proposes an algorithm based on Random forests with color and texture features. The algorithm has three steps. The first step, the polarized light is applied based on the skin's Tyndall-effect in the imaging to eliminate the reflection and Lab color space are used for fitting the human perception. The second step, sliding window and its sub windows are used to get textural feature and color feature. In this step, a feature of image roughness has been defined, so that scaling can be easily separated from normal skin. In the end, Random forests will be used to ensure the generalization ability of the algorithm. This algorithm can give reliable segmentation results even the image has different lighting conditions, skin types. In the data set offered by Union Hospital, more than 90% images can be segmented accurately.

  19. Compaction with automatic jog introduction

    NASA Astrophysics Data System (ADS)

    Maley, F. M.

    1986-05-01

    This thesis presents an algorithm for one-dimensional compaction of VLSI layouts. It differs from older methods in treating wires not as objects to be moved, but as constraints on the positions of other circuit components. These constraints are determined for each wiring layer using the theory of planar routing. Assuming that the wiring layers can be treated independently, the algorithm minimizes the width of a layout, automatically inserting as many jogs in wires as necessary. It runs in time 0(n4) on input of size n. Several heuristics are suggested for improving the algorithm's practical performance. The compaction algorithm takes as input a data structure called a sketch, which explicitly distinguishes between flexible components (wires) and rigid components (modules). The algorithm first finds constraints on the positions of modules that ensure enough space is left for wires. Next, it solves the system of constraints by a standard graph-theoretic technique, obtaining a placement for the modules. It then relies on a single-layer router to restore the wires to each circuit layer. An efficient single-layer router is already known; it is able to minimize the length of every wire, though not the number of jogs. As given, the compaction algorithm applies only to a VLSI model that requires wires to run a rectilinear grid. This restriction is needed only because the theory of planar routing (and single-layer routers) has not yet been extended to other models.

  20. Compaction with automatic jog introduction

    NASA Astrophysics Data System (ADS)

    Maley, E. M.

    1986-11-01

    This thesis presents an algorithm for one-dimensional compaction of VLSI layouts. It differs from older methods in treating wires not as objects to be moved, but as constraints on the positions of other circuit components. These constraints are determined for each wiring layer using the theory of planar routing. Assuming that the wiring layers can be treated independently, the algorithm minimizes the width of a layout, automatically inserting as many jogs in wires as necessary. It runs in time O(n4) on input of size n. Several heuristics are suggested for improving the algorithm's practical performance. The compaction algorithm takes as input a data structure called a sketch, which explicitly distinguished between flexible components (wires) and rigid components (modules). The algorithms first finds constraints on the positions of modules that ensure enough space is left for wires. Next, it solves the system of constraints by a standard graph-theoretic technique, obtaining a placement for the modules. It then relies on a single-layer router to restore the wires to each circuit layer.

  1. Ekofisk automatic GPS subsidence measurements

    SciTech Connect

    Mes, M.J.; Landau, H.; Luttenberger, C.

    1996-10-01

    A fully automatic GPS satellite-based procedure for the reliable measurement of subsidence of several platforms in almost real time is described. Measurements are made continuously on platforms in the North Sea Ekofisk Field area. The procedure also yields rate measurements, which are also essential for confirming platform safety, planning of remedial work, and verification of subsidence models. GPS measurements are more attractive than seabed pressure-gauge-based platform subsidence measurements-they are much cheaper to install and maintain and not subject to gauge drift. GPS measurements were coupled to oceanographic quantities such as the platform deck clearance, which leads to less complex offshore survey procedures. Ekofisk is an oil and gas field in the southern portion of the Norwegian North Sea. Late in 1984, it was noticed that the Ekofisk platform decks were closer to the sea surface than when the platforms were installed-subsidence was the only logical explanation. After the subsidence phenomenon was recognized, an accurate measurement method was needed to measure progression of subsidence and the associated subsidence rate. One available system for which no further development was needed, was the NAVSTAR GPS-measurements started in March 1985.

  2. Automatic image cropping for republishing

    NASA Astrophysics Data System (ADS)

    Cheatle, Phil

    2010-02-01

    Image cropping is an important aspect of creating aesthetically pleasing web pages and repurposing content for different web or printed output layouts. Cropping provides both the possibility of improving the composition of the image, and also the ability to change the aspect ratio of the image to suit the layout design needs of different document or web page formats. This paper presents a method for aesthetically cropping images on the basis of their content. Underlying the approach is a novel segmentation-based saliency method which identifies some regions as "distractions", as an alternative to the conventional "foreground" and "background" classifications. Distractions are a particular problem with typical consumer photos found on social networking websites such as FaceBook, Flickr etc. Automatic cropping is achieved by identifying the main subject area of the image and then using an optimization search to expand this to form an aesthetically pleasing crop. Evaluation of aesthetic functions like auto-crop is difficult as there is no single correct solution. A further contribution of this paper is an automated evaluation method which goes some way towards handling the complexity of aesthetic assessment. This allows crop algorithms to be easily evaluated against a large test set.

  3. Automatic Weather Station (AWS) Lidar

    NASA Technical Reports Server (NTRS)

    Rall, Jonathan A.R.; Abshire, James B.; Spinhirne, James D.; Smith, David E. (Technical Monitor)

    2000-01-01

    An autonomous, low-power atmospheric lidar instrument is being developed at NASA Goddard Space Flight Center. This compact, portable lidar will operate continuously in a temperature controlled enclosure, charge its own batteries through a combination of a small rugged wind generator and solar panels, and transmit its data from remote locations to ground stations via satellite. A network of these instruments will be established by co-locating them at remote Automatic Weather Station (AWS) sites in Antarctica under the auspices of the National Science Foundation (NSF). The NSF Office of Polar Programs provides support to place the weather stations in remote areas of Antarctica in support of meteorological research and operations. The AWS meteorological data will directly benefit the analysis of the lidar data while a network of ground based atmospheric lidar will provide knowledge regarding the temporal evolution and spatial extent of Type la polar stratospheric clouds (PSC). These clouds play a crucial role in the annual austral springtime destruction of stratospheric ozone over Antarctica, i.e. the ozone hole. In addition, the lidar will monitor and record the general atmospheric conditions (transmission and backscatter) of the overlying atmosphere which will benefit the Geoscience Laser Altimeter System (GLAS). Prototype lidar instruments have been deployed to the Amundsen-Scott South Pole Station (1995-96, 2000) and to an Automated Geophysical Observatory site (AGO 1) in January 1999. We report on data acquired with these instruments, instrument performance, and anticipated performance of the AWS Lidar.

  4. Automatic Machine For Spin Testing

    NASA Astrophysics Data System (ADS)

    Carvalho, Fernando D.; Rodrigues, F. Carvalho; Pais, Cassiano P.; Prina, Rogerio

    1989-01-01

    One of the bottle necks of the defence industry is the fuze testing. This task must be performed twice for each fuze. It is a 100% test, since all the fuzes must pass two tests. The arming test is performed at an high rotation speed, and it is necessary to guarantee that a minimum diameter is open. The non arming speed must guarantee that a too small aperture has not happened. The usual way to test the fuzes is the visual inspection by experienced operators. This method presents several problems and is always possible to have some faults. To solve this problem, it was developed a special purpose machine to perform this task in a completely automated way. The results of this development are presented in this paper. The optical system which incorporates a laser and the interface with the mechanics of the machine are analysed. The prototype is installed at INDEP and being used for the automatic testing of the fuzes. A description of the optical system and its characteristics are presented in detail.

  5. Automatic panoramic thermal integrated sensor

    NASA Astrophysics Data System (ADS)

    Gutin, Mikhail A.; Tsui, Eddy K.; Gutin, Olga N.

    2005-05-01

    Historically, the US Army has recognized the advantages of panoramic imagers with high image resolution: increased area coverage with fewer cameras, instantaneous full horizon detection, location and tracking of multiple targets simultaneously, extended range, and others. The novel ViperViewTM high-resolution panoramic thermal imager is the heart of the Automatic Panoramic Thermal Integrated Sensor (APTIS), being jointly developed by Applied Science Innovative, Inc. (ASI) and the Armament Research, Development and Engineering Center (ARDEC) in support of the Future Combat Systems (FCS) and the Intelligent Munitions Systems (IMS). The APTIS is anticipated to operate as an intelligent node in a wireless network of multifunctional nodes that work together to improve situational awareness (SA) in many defense and offensive operations, as well as serve as a sensor node in tactical Intelligence Surveillance Reconnaissance (ISR). The ViperView is as an aberration-corrected omnidirectional imager with small optics designed to match the resolution of a 640x480 pixels IR camera with improved image quality for longer range target detection, classification, and tracking. The same approach is applicable to panoramic cameras working in the visible spectral range. Other components of the ATPIS sensor suite include ancillary sensors, advanced power management, and wakeup capability. This paper describes the development status of the APTIS system.

  6. Automatic Ammunition Identification Technology Project

    SciTech Connect

    Weil, B.

    1993-01-01

    The Automatic Ammunition Identification Technology (AAIT) Project is an activity of the Robotics Process Systems Division at the Oak Ridge National Laboratory (ORNL) for the US Army's Project Manager-Ammunition Logistics (PM-AMMOLOG) at the Picatinny Arsenal in Picatinny, New Jersey. The project objective is to evaluate new two-dimensional bar code symbologies for potential use in ammunition logistics systems and automated reloading equipment. These new symbologies are a significant improvement over typical linear bar codes since machine-readable alphanumeric messages up to 2000 characters long are achievable. These compressed data symbologies are expected to significantly improve logistics and inventory management tasks and permit automated feeding and handling of ammunition to weapon systems. The results will be increased throughout capability, better inventory control, reduction of human error, lower operation and support costs, and a more timely re-supply of various weapon systems. This paper will describe the capabilities of existing compressed data symbologies and the symbol testing activities being conducted at ORNL for the AAIT Project.

  7. Automatic defensive control of asynchronous sequential machines

    NASA Astrophysics Data System (ADS)

    Hammer, Jacob

    2016-01-01

    Control theoretic techniques are utilised to develop automatic controllers that counteract robotic adversarial interventions in the operation of asynchronous sequential machines. The scenario centres on automatic protection against pre-programmed adversarial agents that attempt to subvert the operation of an asynchronous computing system. Necessary and sufficient conditions for the existence of defensive controllers that automatically defeat such adversarial agents are derived. These conditions are stated in terms of skeleton matrices - matrices of zeros and ones obtained directly from the given description of the asynchronous sequential machine being protected. When defensive controllers exist, a procedure for their design is outlined.

  8. On the implementation of automatic differentiation tools.

    SciTech Connect

    Bischof, C. H.; Hovland, P. D.; Norris, B.; Mathematics and Computer Science; Aachen Univ. of Technology

    2008-01-01

    Automatic differentiation is a semantic transformation that applies the rules of differential calculus to source code. It thus transforms a computer program that computes a mathematical function into a program that computes the function and its derivatives. Derivatives play an important role in a wide variety of scientific computing applications, including numerical optimization, solution of nonlinear equations, sensitivity analysis, and nonlinear inverse problems. We describe the forward and reverse modes of automatic differentiation and provide a survey of implementation strategies. We describe some of the challenges in the implementation of automatic differentiation tools, with a focus on tools based on source transformation. We conclude with an overview of current research and future opportunities.

  9. Traceability Through Automatic Program Generation

    NASA Technical Reports Server (NTRS)

    Richardson, Julian; Green, Jeff

    2003-01-01

    Program synthesis is a technique for automatically deriving programs from specifications of their behavior. One of the arguments made in favour of program synthesis is that it allows one to trace from the specification to the program. One way in which traceability information can be derived is to augment the program synthesis system so that manipulations and calculations it carries out during the synthesis process are annotated with information on what the manipulations and calculations were and why they were made. This information is then accumulated throughout the synthesis process, at the end of which, every artifact produced by the synthesis is annotated with a complete history relating it to every other artifact (including the source specification) which influenced its construction. This approach requires modification of the entire synthesis system - which is labor-intensive and hard to do without influencing its behavior. In this paper, we introduce a novel, lightweight technique for deriving traceability from a program specification to the corresponding synthesized code. Once a program has been successfully synthesized from a specification, small changes are systematically made to the specification and the effects on the synthesized program observed. We have partially automated the technique and applied it in an experiment to one of our program synthesis systems, AUTOFILTER, and to the GNU C compiler, GCC. The results are promising: 1. Manual inspection of the results indicates that most of the connections derived from the source (a specification in the case of AUTOFILTER, C source code in the case of GCC) to its generated target (C source code in the case of AUTOFILTER, assembly language code in the case of GCC) are correct. 2. Around half of the lines in the target can be traced to at least one line of the source. 3. Small changes in the source often induce only small changes in the target.

  10. Automaticity in social-cognitive processes.

    PubMed

    Bargh, John A; Schwader, Kay L; Hailey, Sarah E; Dyer, Rebecca L; Boothby, Erica J

    2012-12-01

    Over the past several years, the concept of automaticity of higher cognitive processes has permeated nearly all domains of psychological research. In this review, we highlight insights arising from studies in decision-making, moral judgments, close relationships, emotional processes, face perception and social judgment, motivation and goal pursuit, conformity and behavioral contagion, embodied cognition, and the emergence of higher-level automatic processes in early childhood. Taken together, recent work in these domains demonstrates that automaticity does not result exclusively from a process of skill acquisition (in which a process always begins as a conscious and deliberate one, becoming capable of automatic operation only with frequent use) - there are evolved substrates and early childhood learning mechanisms involved as well.

  11. Automatic mathematical modeling for space application

    NASA Technical Reports Server (NTRS)

    Wang, Caroline K.

    1987-01-01

    A methodology for automatic mathematical modeling is described. The major objective is to create a very friendly environment for engineers to design, maintain and verify their model and also automatically convert the mathematical model into FORTRAN code for conventional computation. A demonstration program was designed for modeling the Space Shuttle Main Engine simulation mathematical model called Propulsion System Automatic Modeling (PSAM). PSAM provides a very friendly and well organized environment for engineers to build a knowledge base for base equations and general information. PSAM contains an initial set of component process elements for the Space Shuttle Main Engine simulation and a questionnaire that allows the engineer to answer a set of questions to specify a particular model. PSAM is then able to automatically generate the model and the FORTRAN code. A future goal is to download the FORTRAN code to the VAX/VMS system for conventional computation.

  12. Automatic Evolution of Molecular Nanotechnology Designs

    NASA Technical Reports Server (NTRS)

    Globus, Al; Lawton, John; Wipke, Todd; Saini, Subhash (Technical Monitor)

    1998-01-01

    This paper describes strategies for automatically generating designs for analog circuits at the molecular level. Software maps out the edges and vertices of potential nanotechnology systems on graphs, then selects appropriate ones through evolutionary or genetic paradigms.

  13. Automatic program timing profiles with FTN4

    SciTech Connect

    Friedman, R.

    1980-09-01

    Design of a scheme for producing execution timing profiles of FORTRAN programs automatically is proposed with a recommendation to implement it as an option to the compiler. An experimental implementation on the LBL 7600 is also described. 1 figure.

  14. A Versatile, Automatic Chromatographic Column Packing Device

    ERIC Educational Resources Information Center

    Barry, Eugene F.; And Others

    1977-01-01

    Describes an inexpensive apparatus for packing liquid and gas chromatographic columns of high efficiency. Consists of stainless steel support struts, an Automat Getriebmotor, and an associated three-pulley system capable of 10, 30, and 300 rpm. (MLH)

  15. Automatic water inventory, collecting, and dispensing unit

    NASA Technical Reports Server (NTRS)

    Hall, J. B., Jr.; Williams, E. F.

    1972-01-01

    Two cylindrical tanks with piston bladders and associated components for automatic filling and emptying use liquid inventory readout devices in control of water flow. Unit provides for adaptive water collection, storage, and dispensation in weightlessness environment.

  16. Automatic program generation from specifications using Prolog

    NASA Technical Reports Server (NTRS)

    Pelin, Alex; Morrow, Paul

    1987-01-01

    An automatic program generator which creates Prolog programs from input/output specifications is presented. The generator takes as input descriptions of the input and output data types, a set of tests, a set of transformations and the input/out relation. Abstract data types are used as models. The tests, the transformations and the input/out relation are also specified by equations. The heuristics used by the automatic propram generator in building Prolog programs are discussed.

  17. Emotional automaticity is a matter of timing.

    PubMed

    Luo, Qian; Holroyd, Tom; Majestic, Catherine; Cheng, Xi; Schechter, Julia; Blair, R James

    2010-04-28

    There has been a long controversy concerning whether the amygdala's response to emotional stimuli is automatic or dependent on attentional load. Using magnoencephalography and an advanced beamformer source localization technique, we found that amygdala automaticity was a function of time: while early amygdala responding to emotional stimuli (40-140 ms) was unaffected by attentional load, later amygdala response (280-410 ms), subsequent to frontoparietal cortex activity, was modulated by attentional load.

  18. Temporal Planning for Automatic Service Composition

    DTIC Science & Technology

    2011-02-28

    Final 3. DATES COVERED (From - To) 01/03/2007 – 30/11/2010 4. TITLE AND SUBTITLE Temporal Planning for Automatic Service Composition 5a. CONTRACT...14. ABSTRACT: This project created, implemented, and evaluated distributed computational mechanisms for automating composition and scheduling of...Temporal Planning for Automatic Service Composition Edmund H. Durfee, University of Michigan 1. Project Objectives: This project’s objectives were to

  19. Automatic welding comes of age. [Offshore

    SciTech Connect

    Turner, D.L. Jr.

    1981-07-01

    Automatic pipe welding systems today fall into three main categories: gas metal arc welding, gas-tungsten arc welding, and flash-butt welding. The first automatic welding devices used offshore were the CRC and H.C. Price systems. Both use gas metal arc welding with a consumable steel filler wire. The recently developed McDermott flash-butt welding system is described. (DLC)

  20. Automatic safety rod for reactors. [LMFBR

    DOEpatents

    Germer, J.H.

    1982-03-23

    An automatic safety rod for a nuclear reactor containing neutron absorbing material and designed to be inserted into a reactor core after a loss-of-flow. Actuation is based upon either a sudden decrease in core pressure drop or the pressure drop decreases below a predetermined minimum value. The automatic control rod includes a pressure regulating device whereby a controlled decrease in operating pressure due to reduced coolant flow does not cause the rod to drop into the core.

  1. Fault-Tolerant, Multiple-Zone Temperature Control

    NASA Technical Reports Server (NTRS)

    Granger, James; Franklin, Brian; Michalik, Martin; Yates, Phillip; Peterson, Erik; Borders, James

    2008-01-01

    A computer program has been written as an essential part of an electronic temperature control system for a spaceborne instrument that contains several zones. The system was developed because the temperature and the rate of change of temperature in each zone are required to be maintained to within limits that amount to degrees of precision thought to be unattainable by use of simple bimetallic thermostats. The software collects temperature readings from six platinum resistance thermometers, calculates temperature errors from the readings, and implements a proportional + integral + derivative (PID) control algorithm that adjusts heater power levels. The software accepts, via a serial port, commands to change its operational parameters. The software attempts to detect and mitigate a host of potential faults. It is robust to many kinds of faults in that it can maintain PID control in the presence of those faults.

  2. A Multiple Zone Method for Supersonic Tactical Missiles

    DTIC Science & Technology

    1986-06-01

    to missile shapes in supersonic flight. The explicit MacCormack scheme is used to advance interior points while a characteristic ...can be treated using a simple mapping. A sample zone structure for a body- wing - tail configuration is shown in Figure 3. This avoids...surface edges which models the flow in the vincinity of the edge. When the flow normal to the wing edge is sufficiently supersonic , this analysis

  3. Reducing airflow energy use in multiple zone vav systems

    NASA Astrophysics Data System (ADS)

    Tukur, Ahmed Gidado

    Variable Air Volume (VAV) systems are the most popular HVAC systems in commercial buildings. VAV systems are designed to deliver airflows at design conditions which only occur for a few hours in a year. Minimizing energy use in VAV systems requires reducing the amount of airflow delivered through the system at part load conditions. Air Handling Unit (AHU) fans are the major drivers of airflow in VAV systems and installing a Variable Frequency Drive (VFD) is the most common method of regulating airflow in VAV systems. A VFD drive does not necessarily save energy without use of an appropriate control strategy. Static pressure reset (SPR) is considered to be the most energy efficient control strategy for AHU fans with VFDs installed. The implementation of SPR however has many challenges; for example, rogue zones--zones which have faulty sensors or failed controls and actuators, system dynamics like hunting and system diversity. By investigating the parameters associated with the implementation of SPR in VAV systems, a new, improved, more stable SPR algorithm was developed and validated. This approach was further improved using Fault Detection and Diagnostics (FDD) to eliminate rogue zones. Additionally, a CO2-Demand Control Ventilation (DCV) based minimum airflow control was used to further reduce ventilation airflow and save more energy from SPR. Energy savings ranging from 25% to 51% were recorded in actual buildings with the new SPR algorithm. Finally, a methodology that utilizes historical VAV data was developed to estimate the potential savings that could be realized using SPR. The approach employed first determines an effective system loss coefficient as a function of mean damper position using the historical duct static pressure, VAV damper positions and airflows. Additionally, the historical data is used to identify the maximum mean duct damper position realizable as a result of insuring a sufficient number of VAVs are fully open at any time. Savings are estimated by shifting the damper distribution mean at each time to this maximum value and reducing the static pressure to achieve the same overall system airflow rate. The methodology was tested on three different buildings with varying system characteristics. Savings estimates correlated well to the savings actually realized from SPR. This result has significant implications for energy service providers, who could use the predictions to guarantee savings from SPR.

  4. Production from multiple zones of a tar sands formation

    DOEpatents

    Karanikas, John Michael; Vinegar, Harold J

    2013-02-26

    A method for treating a tar sands formation includes providing heat to at least part of a hydrocarbon layer in the formation from a plurality of heaters located in the formation. The heat is allowed to transfer from the heaters to at least a portion of the formation. Fluids are produced from the formation through at least one production well that is located in at least two zones in the formation. The first zone has an initial permeability of at least 1 darcy. The second zone has an initial of at most 0.1 darcy. The two zones are separated by a substantially impermeable barrier.

  5. Automatic effects of no-go instructions.

    PubMed

    Liefooghe, Baptist; Degryse, Jasper; Theeuwes, Marijke

    2016-09-01

    Previous research has indicated that stimulus-response mappings that have been instructed but never applied overtly before can lead to automatic response biases when they are irrelevant. In the present study, we investigated whether the same applies to no-go instructions, which relate a stimulus to a no-go response. The results of 2 experiments suggest that a no-go instruction that has never been practiced overtly before can automatically bias responding when it is irrelevant. In addition, the automatic effect of a no-go instruction was similar in size to the automatic effect of a go instruction. Finally, the automatic effect of an unpracticed no-go instruction tended to be larger than the automatic effect of an overtly practiced no-go instruction. We propose that (a) associations between a stimulus and the requirement to stop can be formed on the basis of instructions and without overt practice, (b) these associations may be functionally equivalent to associations formed on the basis of go instructions, and (c) overtly practiced no-go instructions and unpracticed no-go instructions are represented in different formats. (PsycINFO Database Record

  6. The Importance of Automaticity for Developing Expertise in Reading.

    ERIC Educational Resources Information Center

    Samuels, S. Jay; Flor, Richard F.

    1997-01-01

    Discusses how students become automatic at reading sub-skills, the indicators that can be used to determine whether a student is automatic, and the psychological mechanisms that allow students to perform complex skills automatically. Discusses implications of automaticity research for teaching reading. (RS)

  7. 46 CFR 52.01-10 - Automatic controls.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 2 2013-10-01 2013-10-01 false Automatic controls. 52.01-10 Section 52.01-10 Shipping... Requirements § 52.01-10 Automatic controls. (a) Each main boiler must meet the special requirements for automatic safety controls in § 62.35-20(a)(1) of this chapter. (b) Each automatically controlled...

  8. 46 CFR 52.01-10 - Automatic controls.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 2 2012-10-01 2012-10-01 false Automatic controls. 52.01-10 Section 52.01-10 Shipping... Requirements § 52.01-10 Automatic controls. (a) Each main boiler must meet the special requirements for automatic safety controls in § 62.35-20(a)(1) of this chapter. (b) Each automatically controlled...

  9. 46 CFR 52.01-10 - Automatic controls.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 2 2014-10-01 2014-10-01 false Automatic controls. 52.01-10 Section 52.01-10 Shipping... Requirements § 52.01-10 Automatic controls. (a) Each main boiler must meet the special requirements for automatic safety controls in § 62.35-20(a)(1) of this chapter. (b) Each automatically controlled...

  10. 46 CFR 52.01-10 - Automatic controls.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 2 2011-10-01 2011-10-01 false Automatic controls. 52.01-10 Section 52.01-10 Shipping... Requirements § 52.01-10 Automatic controls. (a) Each main boiler must meet the special requirements for automatic safety controls in § 62.35-20(a)(1) of this chapter. (b) Each automatically controlled...

  11. 46 CFR 63.25-1 - Small automatic auxiliary boilers.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 2 2013-10-01 2013-10-01 false Small automatic auxiliary boilers. 63.25-1 Section 63.25... AUXILIARY BOILERS Requirements for Specific Types of Automatic Auxiliary Boilers § 63.25-1 Small automatic auxiliary boilers. Small automatic auxiliary boilers defined as having heat-input ratings of 400,000...

  12. 46 CFR 63.25-1 - Small automatic auxiliary boilers.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Small automatic auxiliary boilers. 63.25-1 Section 63.25... AUXILIARY BOILERS Requirements for Specific Types of Automatic Auxiliary Boilers § 63.25-1 Small automatic auxiliary boilers. Small automatic auxiliary boilers defined as having heat-input ratings of 400,000...

  13. 46 CFR 63.25-1 - Small automatic auxiliary boilers.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 2 2014-10-01 2014-10-01 false Small automatic auxiliary boilers. 63.25-1 Section 63.25... AUXILIARY BOILERS Requirements for Specific Types of Automatic Auxiliary Boilers § 63.25-1 Small automatic auxiliary boilers. Small automatic auxiliary boilers defined as having heat-input ratings of 400,000...

  14. 46 CFR 63.25-1 - Small automatic auxiliary boilers.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 2 2012-10-01 2012-10-01 false Small automatic auxiliary boilers. 63.25-1 Section 63.25... AUXILIARY BOILERS Requirements for Specific Types of Automatic Auxiliary Boilers § 63.25-1 Small automatic auxiliary boilers. Small automatic auxiliary boilers defined as having heat-input ratings of 400,000...

  15. 46 CFR 63.25-1 - Small automatic auxiliary boilers.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 2 2011-10-01 2011-10-01 false Small automatic auxiliary boilers. 63.25-1 Section 63.25... AUXILIARY BOILERS Requirements for Specific Types of Automatic Auxiliary Boilers § 63.25-1 Small automatic auxiliary boilers. Small automatic auxiliary boilers defined as having heat-input ratings of 400,000...

  16. 30 CFR 27.23 - Automatic warning device.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Automatic warning device. 27.23 Section 27.23... Automatic warning device. (a) An automatic warning device shall be suitably constructed for incorporation in... automatic warning device shall include an alarm signal (audible or colored light), which shall be made...

  17. 30 CFR 27.23 - Automatic warning device.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Automatic warning device. 27.23 Section 27.23... Automatic warning device. (a) An automatic warning device shall be suitably constructed for incorporation in... automatic warning device shall include an alarm signal (audible or colored light), which shall be made...

  18. 30 CFR 27.23 - Automatic warning device.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Automatic warning device. 27.23 Section 27.23... Automatic warning device. (a) An automatic warning device shall be suitably constructed for incorporation in... automatic warning device shall include an alarm signal (audible or colored light), which shall be made...

  19. 46 CFR 52.01-10 - Automatic controls.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Automatic controls. 52.01-10 Section 52.01-10 Shipping... Requirements § 52.01-10 Automatic controls. (a) Each main boiler must meet the special requirements for automatic safety controls in § 62.35-20(a)(1) of this chapter. (b) Each automatically controlled...

  20. Practical automatic Arabic license plate recognition system

    NASA Astrophysics Data System (ADS)

    Mohammad, Khader; Agaian, Sos; Saleh, Hani

    2011-02-01

    Since 1970's, the need of an automatic license plate recognition system, sometimes referred as Automatic License Plate Recognition system, has been increasing. A license plate recognition system is an automatic system that is able to recognize a license plate number, extracted from image sensors. In specific, Automatic License Plate Recognition systems are being used in conjunction with various transportation systems in application areas such as law enforcement (e.g. speed limit enforcement) and commercial usages such as parking enforcement and automatic toll payment private and public entrances, border control, theft and vandalism control. Vehicle license plate recognition has been intensively studied in many countries. Due to the different types of license plates being used, the requirement of an automatic license plate recognition system is different for each country. [License plate detection using cluster run length smoothing algorithm ].Generally, an automatic license plate localization and recognition system is made up of three modules; license plate localization, character segmentation and optical character recognition modules. This paper presents an Arabic license plate recognition system that is insensitive to character size, font, shape and orientation with extremely high accuracy rate. The proposed system is based on a combination of enhancement, license plate localization, morphological processing, and feature vector extraction using the Haar transform. The performance of the system is fast due to classification of alphabet and numerals based on the license plate organization. Experimental results for license plates of two different Arab countries show an average of 99 % successful license plate localization and recognition in a total of more than 20 different images captured from a complex outdoor environment. The results run times takes less time compared to conventional and many states of art methods.

  1. Attention to Automatic Movements in Parkinson's Disease: Modified Automatic Mode in the Striatum.

    PubMed

    Wu, Tao; Liu, Jun; Zhang, Hejia; Hallett, Mark; Zheng, Zheng; Chan, Piu

    2015-10-01

    We investigated neural correlates when attending to a movement that could be made automatically in healthy subjects and Parkinson's disease (PD) patients. Subjects practiced a visuomotor association task until they could perform it automatically, and then directed their attention back to the automated task. Functional MRI was obtained during the early-learning, automatic stage, and when re-attending. In controls, attention to automatic movement induced more activation in the dorsolateral prefrontal cortex (DLPFC), anterior cingulate cortex, and rostral supplementary motor area. The motor cortex received more influence from the cortical motor association regions. In contrast, the pattern of the activity and connectivity of the striatum remained at the level of the automatic stage. In PD patients, attention enhanced activity in the DLPFC, premotor cortex, and cerebellum, but the connectivity from the putamen to the motor cortex decreased. Our findings demonstrate that, in controls, when a movement achieves the automatic stage, attention can influence the attentional networks and cortical motor association areas, but has no apparent effect on the striatum. In PD patients, attention induces a shift from the automatic mode back to the controlled pattern within the striatum. The shifting between controlled and automatic behaviors relies in part on striatal function.

  2. Automatic Fastening Large Structures: a New Approach

    NASA Technical Reports Server (NTRS)

    Lumley, D. F.

    1985-01-01

    The external tank (ET) intertank structure for the space shuttle, a 27.5 ft diameter 22.5 ft long externally stiffened mechanically fastened skin-stringer-frame structure, was a labor intensitive manual structure built on a modified Saturn tooling position. A new approach was developed based on half-section subassemblies. The heart of this manufacturing approach will be 33 ft high vertical automatic riveting system with a 28 ft rotary positioner coming on-line in mid 1985. The Automatic Riveting System incorporates many of the latest automatic riveting technologies. Key features include: vertical columns with two sets of independently operating CNC drill-riveting heads; capability of drill, insert and upset any one piece fastener up to 3/8 inch diameter including slugs without displacing the workpiece offset bucking ram with programmable rotation and deep retraction; vision system for automatic parts program re-synchronization and part edge margin control; and an automatic rivet selection/handling system.

  3. Automatic prejudice in childhood and early adolescence.

    PubMed

    Degner, Juliane; Wentura, Dirk

    2010-03-01

    Four cross-sectional studies are presented that investigated the automatic activation of prejudice in children and adolescents (aged 9 years to 15 years). Therefore, 4 different versions of the affective priming task were used, with pictures of ingroup and outgroup members being presented as prejudice-related prime stimuli. In all 4 studies, a pattern occurred that suggests a linear developmental increase of automatic prejudice with significant effects of outgroup negativity appearing only around the ages of 12 to 13 years. Results of younger children, on the contrary, did not indicate any effect of automatic prejudice activation. In contrast, prejudice effects in an Implicit Association Test (IAT) showed high levels of prejudice independent of age (Study 3). Results of Study 4 suggest that these age differences are due to age-related differences in spontaneous categorization processes. Introducing a forced-categorization into the affective priming procedure produced a pattern of results equivalent to that obtained with the IAT. These results suggest that although children are assumed to acquire prejudice at much younger ages, automatization of such attitudes might be related to developmental processes in early adolescence. We discuss possible theoretical implications of these results for a developmental theory of prejudice representation and automatization during childhood and adolescence.

  4. Automatic radioxenon analyzer for CTBT monitoring

    SciTech Connect

    Bowyer, T.W.; Abel, K.H.; Hensley, W.K.

    1996-12-01

    Over the past 3 years, with support from US DOE`s NN-20 Comprehensive Test Ban Treaty (CTBT) R&D program, PNNL has developed and demonstrated a fully automatic analyzer for collecting and measuring the four Xe radionuclides, {sup 131m}Xe(11.9 d), {sup 133m}Xe(2.19 d), {sup 133}Xe (5.24 d), and {sup 135}Xe(9.10 h), in the atmosphere. These radionuclides are important signatures in monitoring for compliance to a CTBT. Activity ratios permit discriminating radioxenon from nuclear detonation and that from nuclear reactor operations, nuclear fuel reprocessing, or medical isotope production and usage. In the analyzer, Xe is continuously and automatically separated from the atmosphere at flow rates of about 7 m{sup 3}/h on sorption bed. Aliquots collected for 6-12 h are automatically analyzed by electron-photon coincidence spectrometry to produce sensitivities in the range of 20-100 {mu}Bq/m{sup 3} of air, about 100-fold better than with reported laboratory-based procedures for short time collection intervals. Spectral data are automatically analyzed and the calculated radioxenon concentrations and raw gamma- ray spectra automatically transmitted to data centers.

  5. Recycling steel automatically -- through resource recovery

    SciTech Connect

    Crawford, G.L.

    1996-12-31

    More than three-fourths of the operating resource recovery plants magnetically separate steel cans and other discarded steel items either pre- or post-combustion. This last year, 121 resource recovery facilities combusted about 14% of the solid waste for communities across the US. Automatic recycling of steel clearly reduces the post-combustion material that is landfilled and heightens the facilities environmental performance through tangible recycling achievement. Even though about one out of every six steel cans is recycled automatically through resource recovery, not many people are aware of automatic recycling of steel cans through resource recovery. How many people know that their local resource recovery plant is insuring that virtually all of their food, beverage and general purpose cans--including paint and aerosol--are being recycled so easily and efficiently? Magnetic separation at resource recovery facilities is a fundamentally simple and desirable method of diverting what would otherwise be relegated as solid waste to the landfill. It should be recognized as an increasingly important and valued part of the resource recovery and steel industries overall recycling efforts. This paper will provide the latest information on steel recycled automatically from resource recovery facilities within the total context of all recycling accomplished annually by the steel industry. Most important, recommendations are provided for building public awareness of the automatic steel recycling contribution made so solidly by resource recovery facilities.

  6. Automatically processed alpha-track radon monitor

    DOEpatents

    Langner, G.H. Jr.

    1993-01-12

    An automatically processed alpha-track radon monitor is provided which includes a housing having an aperture allowing radon entry, and a filter that excludes the entry of radon daughters into the housing. A flexible track registration material is located within the housing that records alpha-particle emissions from the decay of radon and radon daughters inside the housing. The flexible track registration material is capable of being spliced such that the registration material from a plurality of monitors can be spliced into a single strip to facilitate automatic processing of the registration material from the plurality of monitors. A process for the automatic counting of radon registered by a radon monitor is also provided.

  7. Automatically processed alpha-track radon monitor

    DOEpatents

    Langner, Jr., G. Harold

    1993-01-01

    An automatically processed alpha-track radon monitor is provided which includes a housing having an aperture allowing radon entry, and a filter that excludes the entry of radon daughters into the housing. A flexible track registration material is located within the housing that records alpha-particle emissions from the decay of radon and radon daughters inside the housing. The flexible track registration material is capable of being spliced such that the registration material from a plurality of monitors can be spliced into a single strip to facilitate automatic processing of the registration material from the plurality of monitors. A process for the automatic counting of radon registered by a radon monitor is also provided.

  8. Automatically processed alpha-track radon monitor

    SciTech Connect

    Langner, G.H. Jr.

    1991-05-02

    An automatically processed alpha-track radon monitor is provided which includes a housing having an aperture allowing radon entry, and a filter that excludes the entry of radon daughters into the housing. A flexible track registration material is located within the housing that records alpha-particle emissions from the decay of radon and radon daughters inside the housing. The flexible track registration material is capable of being spliced such that the registration material from a plurality of monitors can be spliced into a single strip to facilitate automatic processing of the registration material from the plurality of monitors. A process for the automatic counting of radon registered by a radon monitor is also provided.

  9. Automatic Welding of Stainless Steel Tubing

    NASA Technical Reports Server (NTRS)

    Clautice, W. E.

    1978-01-01

    To determine if the use of automatic welding would allow reduction of the radiographic inspection requirement, and thereby reduce fabrication costs, a series of welding tests were performed. In these tests an automatic welder was used on stainless steel tubing of 1/2, 3/4, and 1/2 inch diameter size. The optimum parameters were investigated to determine how much variation from optimum in machine settings could be tolerate and still result in a good quality weld. The process variables studied were the welding amperes, the revolutions per minute as a function of the circumferential weld travel speed, and the shielding gas flow. The investigation showed that the close control of process variables in conjunction with a thorough visual inspection of welds can be relied upon as an acceptable quality assurance procedure, thus permitting the radiographic inspection to be reduced by a large percentage when using the automatic process.

  10. Automatic alignment method for calibration of hydrometers

    NASA Astrophysics Data System (ADS)

    Lee, Y. J.; Chang, K. H.; Chon, J. C.; Oh, C. Y.

    2004-04-01

    This paper presents a new method to automatically align specific scale-marks for the calibration of hydrometers. A hydrometer calibration system adopting the new method consists of a vision system, a stepping motor, and software to control the system. The vision system is composed of a CCD camera and a frame grabber, and is used to acquire images. The stepping motor moves the camera, which is attached to the vessel containing a reference liquid, along the hydrometer. The operating program has two main functions: to process images from the camera to find the position of the horizontal plane and to control the stepping motor for the alignment of the horizontal plane with a particular scale-mark. Any system adopting this automatic alignment method is a convenient and precise means of calibrating a hydrometer. The performance of the proposed method is illustrated by comparing the calibration results using the automatic alignment method with those obtained using the manual method.

  11. Automatic exposure control for space sequential camera

    NASA Technical Reports Server (NTRS)

    Mcatee, G. E., Jr.; Stoap, L. J.; Solheim, C. D.; Sharpsteen, J. T.

    1975-01-01

    The final report for the automatic exposure control study for space sequential cameras, for the NASA Johnson Space Center is presented. The material is shown in the same sequence that the work was performed. The purpose of the automatic exposure control is to automatically control the lens iris as well as the camera shutter so that the subject is properly exposed on the film. A study of design approaches is presented. Analysis of the light range of the spectrum covered indicates that the practical range would be from approximately 20 to 6,000 foot-lamberts, or about nine f-stops. Observation of film available from space flights shows that optimum scene illumination is apparently not present in vehicle interior photography as well as in vehicle-to-vehicle situations. The evaluation test procedure for a breadboard, and the results, which provided information for the design of a brassboard are given.

  12. Automatic weld torch guidance control system

    NASA Technical Reports Server (NTRS)

    Smaith, H. E.; Wall, W. A.; Burns, M. R., Jr.

    1982-01-01

    A highly reliable, fully digital, closed circuit television optical, type automatic weld seam tracking control system was developed. This automatic tracking equipment is used to reduce weld tooling costs and increase overall automatic welding reliability. The system utilizes a charge injection device digital camera which as 60,512 inidividual pixels as the light sensing elements. Through conventional scanning means, each pixel in the focal plane is sequentially scanned, the light level signal digitized, and an 8-bit word transmitted to scratch pad memory. From memory, the microprocessor performs an analysis of the digital signal and computes the tracking error. Lastly, the corrective signal is transmitted to a cross seam actuator digital drive motor controller to complete the closed loop, feedback, tracking system. This weld seam tracking control system is capable of a tracking accuracy of + or - 0.2 mm, or better. As configured, the system is applicable to square butt, V-groove, and lap joint weldments.

  13. Automatic metro map layout using multicriteria optimization.

    PubMed

    Stott, Jonathan; Rodgers, Peter; Martínez-Ovando, Juan Carlos; Walker, Stephen G

    2011-01-01

    This paper describes an automatic mechanism for drawing metro maps. We apply multicriteria optimization to find effective placement of stations with a good line layout and to label the map unambiguously. A number of metrics are defined, which are used in a weighted sum to find a fitness value for a layout of the map. A hill climbing optimizer is used to reduce the fitness value, and find improved map layouts. To avoid local minima, we apply clustering techniques to the map-the hill climber moves both stations and clusters when finding improved layouts. We show the method applied to a number of metro maps, and describe an empirical study that provides some quantitative evidence that automatically-drawn metro maps can help users to find routes more efficiently than either published maps or undistorted maps. Moreover, we have found that, in these cases, study subjects indicate a preference for automatically-drawn maps over the alternatives.

  14. Support vector machine for automatic pain recognition

    NASA Astrophysics Data System (ADS)

    Monwar, Md Maruf; Rezaei, Siamak

    2009-02-01

    Facial expressions are a key index of emotion and the interpretation of such expressions of emotion is critical to everyday social functioning. In this paper, we present an efficient video analysis technique for recognition of a specific expression, pain, from human faces. We employ an automatic face detector which detects face from the stored video frame using skin color modeling technique. For pain recognition, location and shape features of the detected faces are computed. These features are then used as inputs to a support vector machine (SVM) for classification. We compare the results with neural network based and eigenimage based automatic pain recognition systems. The experiment results indicate that using support vector machine as classifier can certainly improve the performance of automatic pain recognition system.

  15. An Automatic Speed Control for Wind Tunnels

    NASA Technical Reports Server (NTRS)

    Zahm, A F

    1928-01-01

    Described here is an automatic control that has been used in several forms in wind tunnels at the Washington Navy Yard. The form now in use with the 8-foot tunnel at the Navy Yard is considered here. Details of the design and operation of the automatic control system are given. Leads from a Pitot tube are joined to an inverted cup manometer located above a rheostat. When the sliding weight of this instrument is set to a given notch, say for 40 m.p.h, the beam tip vibrates between two electric contacts that feed the little motor. Thus, when the wind is too strong or too weak, the motor automatically throws the rheostat slide forward and backward. If it failed to function well, the operator would notice the effect on his meniscus, and would operate the hand control by merely pressing the switch.

  16. Automatic discrimination of emotion from spoken Finnish.

    PubMed

    Toivanen, Juhani; Väyrynen, Eero; Seppänen, Tapio

    2004-01-01

    In this paper, experiments on the automatic discrimination of basic emotions from spoken Finnish are described. For the purpose of the study, a large emotional speech corpus of Finnish was collected; 14 professional actors acted as speakers, and simulated four primary emotions when reading out a semantically neutral text. More than 40 prosodic features were derived and automatically computed from the speech samples. Two application scenarios were tested: the first scenario was speaker-independent for a small domain of speakers while the second scenario was completely speaker-independent. Human listening experiments were conducted to assess the perceptual adequacy of the emotional speech samples. Statistical classification experiments indicated that, with the optimal combination of prosodic feature vectors, automatic emotion discrimination performance close to human emotion recognition ability was achievable.

  17. Automatic cardiac MRI myocardium segmentation using graphcut

    NASA Astrophysics Data System (ADS)

    Kedenburg, Gunnar; Cocosco, Chris A.; Köthe, Ullrich; Niessen, Wiro J.; Vonken, Evert-jan P. A.; Viergever, Max A.

    2006-03-01

    Segmentation of the left myocardium in four-dimensional (space-time) cardiac MRI data sets is a prerequisite of many diagnostic tasks. We propose a fully automatic method based on global minimization of an energy functional by means of the graphcut algorithm. Starting from automatically obtained segmentations of the left and right ventricles and a cardiac region of interest, a spatial model is constructed using simple and plausible assumptions. This model is used to learn the appearance of different tissue types by non parametric robust estimation. Our method does not require previously trained shape or appearance models. Processing takes 30-40s on current hardware. We evaluated our method on 11 clinical cardiac MRI data sets acquired using cine balanced fast field echo. Linear regression of the automatically segmented myocardium volume against manual segmentations (performed by a radiologist) showed an RMS error of about 12ml.

  18. Semi-automatic knee cartilage segmentation

    NASA Astrophysics Data System (ADS)

    Dam, Erik B.; Folkesson, Jenny; Pettersen, Paola C.; Christiansen, Claus

    2006-03-01

    Osteo-Arthritis (OA) is a very common age-related cause of pain and reduced range of motion. A central effect of OA is wear-down of the articular cartilage that otherwise ensures smooth joint motion. Quantification of the cartilage breakdown is central in monitoring disease progression and therefore cartilage segmentation is required. Recent advances allow automatic cartilage segmentation with high accuracy in most cases. However, the automatic methods still fail in some problematic cases. For clinical studies, even if a few failing cases will be averaged out in the overall results, this reduces the mean accuracy and precision and thereby necessitates larger/longer studies. Since the severe OA cases are often most problematic for the automatic methods, there is even a risk that the quantification will introduce a bias in the results. Therefore, interactive inspection and correction of these problematic cases is desirable. For diagnosis on individuals, this is even more crucial since the diagnosis will otherwise simply fail. We introduce and evaluate a semi-automatic cartilage segmentation method combining an automatic pre-segmentation with an interactive step that allows inspection and correction. The automatic step consists of voxel classification based on supervised learning. The interactive step combines a watershed transformation of the original scan with the posterior probability map from the classification step at sub-voxel precision. We evaluate the method for the task of segmenting the tibial cartilage sheet from low-field magnetic resonance imaging (MRI) of knees. The evaluation shows that the combined method allows accurate and highly reproducible correction of the segmentation of even the worst cases in approximately ten minutes of interaction.

  19. System for automatically switching transformer coupled lines

    NASA Technical Reports Server (NTRS)

    Dwinell, W. S. (Inventor)

    1979-01-01

    A system is presented for automatically controlling transformer coupled alternating current electric lines. The secondary winding of each transformer is provided with a center tap. A switching circuit is connected to the center taps of a pair of secondary windings and includes a switch controller. An impedance is connected between the center taps of the opposite pair of secondary windings. The switching circuit has continuity when the AC lines are continuous and discontinuity with any disconnect of the AC lines. Normally open switching means are provided in at least one AC line. The switch controller automatically opens the switching means when the AC lines become separated.

  20. Automatic tools for microprocessor failure analysis

    NASA Astrophysics Data System (ADS)

    Conard, Didier; Laurent, J.; Velazco, Raoul; Ziade, Haissam; Cabestany, J.; Sala, F.

    A new approach for fault location when testing microprocessors is presented. The startpoint for the backtracing analysis converging to the failure is constituted by the automatic localization of a reduced area. Automatic image comparison based on pattern recognition is performed by means of an electron beam tester. The developed hardware and software tools allow large circuit areas to be covered offering powerful diagnosis capabilities to the user. The validation of this technique was performed on faulty 68000 microprocessors. It shows the feasibility of the automation of the first and most important step of failure analysis: fault location at the chip surface.

  1. Automatic threshold selection using histogram quantization

    NASA Astrophysics Data System (ADS)

    Wang, Yue; Adali, Tulay; Lo, Shih-Chung B.

    1997-04-01

    An automatic threshold selection method is proposed for biomedical image analysis based on a histogram coding scheme. The threshold values can be determined based on the well-known Lloyd-Max scalar quantization rule, which is optimal in the sense of achieving minimum mean-square-error distortion. An iterative self-organizing learning rule is derived to determine the threshold levels. The rule does not require any prior information about the histogram, hence is fully automatic. Experimental results show that this new approach is easy to implement yet is highly efficient, robust with respect to noise, and yields reliable estimates of the threshold levels.

  2. Bayesian Automatic Classification Of HMI Images

    NASA Astrophysics Data System (ADS)

    Ulrich, R. K.; Beck, John G.

    2011-05-01

    The Bayesian automatic classification system known as "AutoClass" finds a set of class definitions based on a set of observed data and assigns data to classes without human supervision. It has been applied to Mt Wilson data to improve modeling of total solar irradiance variations (Ulrich, et al, 2010). We apply AutoClass to HMI observables to automatically identify regions of the solar surface. To prevent small instrument artifacts from interfering with class identification, we apply a flat-field correction and a rotationally shifted temporal average to the HMI images prior to processing with AutoClass. Additionally, the sensitivity of AutoClass to instrumental artifacts is investigated.

  3. Automatic emotional expression analysis from eye area

    NASA Astrophysics Data System (ADS)

    Akkoç, Betül; Arslan, Ahmet

    2015-02-01

    Eyes play an important role in expressing emotions in nonverbal communication. In the present study, emotional expression classification was performed based on the features that were automatically extracted from the eye area. Fırst, the face area and the eye area were automatically extracted from the captured image. Afterwards, the parameters to be used for the analysis through discrete wavelet transformation were obtained from the eye area. Using these parameters, emotional expression analysis was performed through artificial intelligence techniques. As the result of the experimental studies, 6 universal emotions consisting of expressions of happiness, sadness, surprise, disgust, anger and fear were classified at a success rate of 84% using artificial neural networks.

  4. Automatic Control Of Length Of Welding Arc

    NASA Technical Reports Server (NTRS)

    Iceland, William F.

    1991-01-01

    Nonlinear relationships among current, voltage, and length stored in electronic memory. Conceptual microprocessor-based control subsystem maintains constant length of welding arc in gas/tungsten arc-welding system, even when welding current varied. Uses feedback of current and voltage from welding arc. Directs motor to set position of torch according to previously measured relationships among current, voltage, and length of arc. Signal paths marked "calibration" or "welding" used during those processes only. Other signal paths used during both processes. Control subsystem added to existing manual or automatic welding system equipped with automatic voltage control.

  5. Automatic identification of species with neural networks

    PubMed Central

    Jiménez-Segura, Luz Fernanda

    2014-01-01

    A new automatic identification system using photographic images has been designed to recognize fish, plant, and butterfly species from Europe and South America. The automatic classification system integrates multiple image processing tools to extract the geometry, morphology, and texture of the images. Artificial neural networks (ANNs) were used as the pattern recognition method. We tested a data set that included 740 species and 11,198 individuals. Our results show that the system performed with high accuracy, reaching 91.65% of true positive fish identifications, 92.87% of plants and 93.25% of butterflies. Our results highlight how the neural networks are complementary to species identification. PMID:25392749

  6. Speech production knowledge in automatic speech recognition.

    PubMed

    King, Simon; Frankel, Joe; Livescu, Karen; McDermott, Erik; Richmond, Korin; Wester, Mirjam

    2007-02-01

    Although much is known about how speech is produced, and research into speech production has resulted in measured articulatory data, feature systems of different kinds, and numerous models, speech production knowledge is almost totally ignored in current mainstream approaches to automatic speech recognition. Representations of speech production allow simple explanations for many phenomena observed in speech which cannot be easily analyzed from either acoustic signal or phonetic transcription alone. In this article, a survey of a growing body of work in which such representations are used to improve automatic speech recognition is provided.

  7. Automatically Detecting Authors’ Native Language

    DTIC Science & Technology

    2011-03-01

    for detecting Chinese and Japanese, but it performed less well with Slavic and Romance languages . Empirical analysis of character trigrams also...well for detecting Chinese and Japanese, but it performed less well with Slavics and Romance languages . We also compared the overall performance...NAVAL POSTGRADUATE SCHOOL MONTEREY, CALIFORNIA THESIS AUTOMATICALLY DETECTING AUTHORS’ NATIVE LANGUAGE by Charles S. Ahn March 2011 Thesis Advisor

  8. Automatic spatiotemporal matching of detected pleural thickenings

    NASA Astrophysics Data System (ADS)

    Chaisaowong, Kraisorn; Keller, Simon Kai; Kraus, Thomas

    2014-01-01

    Pleural thickenings can be found in asbestos exposed patient's lung. Non-invasive diagnosis including CT imaging can detect aggressive malignant pleural mesothelioma in its early stage. In order to create a quantitative documentation of automatic detected pleural thickenings over time, the differences in volume and thickness of the detected thickenings have to be calculated. Physicians usually estimate the change of each thickening via visual comparison which provides neither quantitative nor qualitative measures. In this work, automatic spatiotemporal matching techniques of the detected pleural thickenings at two points of time based on the semi-automatic registration have been developed, implemented, and tested so that the same thickening can be compared fully automatically. As result, the application of the mapping technique using the principal components analysis turns out to be advantageous than the feature-based mapping using centroid and mean Hounsfield Units of each thickening, since the resulting sensitivity was improved to 98.46% from 42.19%, while the accuracy of feature-based mapping is only slightly higher (84.38% to 76.19%).

  9. MARZ: Manual and automatic redshifting software

    NASA Astrophysics Data System (ADS)

    Hinton, S. R.; Davis, Tamara M.; Lidman, C.; Glazebrook, K.; Lewis, G. F.

    2016-04-01

    The Australian Dark Energy Survey (OzDES) is a 100-night spectroscopic survey underway on the Anglo-Australian Telescope using the fibre-fed 2-degree-field (2dF) spectrograph. We have developed a new redshifting application MARZ with greater usability, flexibility, and the capacity to analyse a wider range of object types than the RUNZ software package previously used for redshifting spectra from 2dF. MARZ is an open-source, client-based, Javascript web-application which provides an intuitive interface and powerful automatic matching capabilities on spectra generated from the AAOmega spectrograph to produce high quality spectroscopic redshift measurements. The software can be run interactively or via the command line, and is easily adaptable to other instruments and pipelines if conforming to the current FITS file standard is not possible. Behind the scenes, a modified version of the AUTOZ cross-correlation algorithm is used to match input spectra against a variety of stellar and galaxy templates, and automatic matching performance for OzDES spectra has increased from 54% (RUNZ) to 91% (MARZ). Spectra not matched correctly by the automatic algorithm can be easily redshifted manually by cycling automatic results, manual template comparison, or marking spectral features.

  10. Automatic Keypress Activation in Skilled Typing

    ERIC Educational Resources Information Center

    Rieger, Martina

    2004-01-01

    The assumption that letters automatically activate corresponding keypresses in skilled typing was investigated. Participants responded to the color of letters (congruent condition: responding finger was the one usually used to type the letter). Participants skilled in typing showed a congruency effect: unskilled participants did not (Experiment…

  11. Automatic Activation of Exercise and Sedentary Stereotypes

    ERIC Educational Resources Information Center

    Berry, Tanya; Spence, John C.

    2009-01-01

    We examined the automatic activation of "sedentary" and "exerciser" stereotypes using a social prime Stroop task. Results showed significantly slower response times between the exercise words and the exercise control words and between the sedentary words and the exercise control words when preceded by an attractive exerciser prime. Words preceded…

  12. Operational efficiency: Automatic ascent flight design

    NASA Technical Reports Server (NTRS)

    1990-01-01

    Major objectives, milestones, key contacts, major accomplishments, technology issues, and candidate programs of the automatic ascent flight design are outlined. Topics discussed include: advanced avionics concepts; advanced training concepts; telerobotics/telepresence; integrated command and control; advanced software integration; atmospheric adaptive guidance; and health status and monitoring concept. This presentation is represented by viewgraphs only.

  13. Creative Automaticity: The Writing of Business Spanish.

    ERIC Educational Resources Information Center

    Nino-Murcia, Mercedes

    Ways to develop "creative automaticity" for writing in a foreign language are examined. The paper focuses on transactional writing (i.e., writing with the purpose of transferring precise information by such means as telex messages, business letters, memoranda, and short reports), and its main features of clarity and conventionality. It is noted…

  14. Automatically Locking/Unlocking Orthotic Knee Joint

    NASA Technical Reports Server (NTRS)

    Weddendorf, Bruce

    1994-01-01

    Proposed orthotic knee joint locks and unlocks automatically, at any position within range of bend angles, without manual intervention by wearer. Includes tang and clevis, locks whenever wearer transfers weight to knee and unlocks when weight removed. Locking occurs at any angle between 45 degrees knee bend and full extension.

  15. RFID: A Revolution in Automatic Data Recognition

    ERIC Educational Resources Information Center

    Deal, Walter F., III

    2004-01-01

    Radio frequency identification, or RFID, is a generic term for technologies that use radio waves to automatically identify people or objects. There are several methods of identification, but the most common is to store a serial number that identifies a person or object, and perhaps other information, on a microchip that is attached to an antenna…

  16. 6 CFR 7.28 - Automatic declassification.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... from automatic declassification pursuant to section 3.3 (b) through (d) of Executive Order 12958, as... Chief Security Officer shall notify the ISOO of any specific information that DHS proposes to exempt... classified for a longer period of time; and (3) A specific date or event for declassification of...

  17. Laser tracking system with automatic reacquisition capability.

    PubMed

    Johnson, R E; Weiss, P F

    1968-06-01

    A laser based tracking system is described that has the capability of automatically performing an acquisition search to locate the target. This work is intended for precision launch phase tracking of the Saturn V launch vehicle. System tracking accuracies limited only by the atmosphere have been demonstrated, as has acquisition over a 1 degrees x 1 degrees field of view.

  18. 38 CFR 51.31 - Automatic recognition.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...) PER DIEM FOR NURSING HOME CARE OF VETERANS IN STATE HOMES Obtaining Per Diem for Nursing Home Care in... that already is recognized by VA as a State home for nursing home care at the time this part becomes effective, automatically will continue to be recognized as a State home for nursing home care but will...

  19. 38 CFR 51.31 - Automatic recognition.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...) PER DIEM FOR NURSING HOME CARE OF VETERANS IN STATE HOMES Obtaining Per Diem for Nursing Home Care in... that already is recognized by VA as a State home for nursing home care at the time this part becomes effective, automatically will continue to be recognized as a State home for nursing home care but will...

  20. 38 CFR 51.31 - Automatic recognition.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...) PER DIEM FOR NURSING HOME CARE OF VETERANS IN STATE HOMES Obtaining Per Diem for Nursing Home Care in... that already is recognized by VA as a State home for nursing home care at the time this part becomes effective, automatically will continue to be recognized as a State home for nursing home care but will...

  1. 38 CFR 51.31 - Automatic recognition.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...) PER DIEM FOR NURSING HOME CARE OF VETERANS IN STATE HOMES Obtaining Per Diem for Nursing Home Care in... that already is recognized by VA as a State home for nursing home care at the time this part becomes effective, automatically will continue to be recognized as a State home for nursing home care but will...

  2. 38 CFR 51.31 - Automatic recognition.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...) PER DIEM FOR NURSING HOME CARE OF VETERANS IN STATE HOMES Obtaining Per Diem for Nursing Home Care in... that already is recognized by VA as a State home for nursing home care at the time this part becomes effective, automatically will continue to be recognized as a State home for nursing home care but will...

  3. Automatic Thesaurus Construction Using Bayesian Networks.

    ERIC Educational Resources Information Center

    Park, Young C.; Choi, Key-Sun

    1996-01-01

    Discusses automatic thesaurus construction and characterizes the statistical behavior of terms by using an inference network. Highlights include low-frequency terms and data sparseness, Bayesian networks, collocation maps and term similarity, constructing a thesaurus from a collocation map, and experiments with test collections. (Author/LRW)

  4. Low Speed Control for Automatic Welding

    NASA Technical Reports Server (NTRS)

    Iceland, W. E.

    1982-01-01

    Amplifier module allows rotating positioner of automatic welding machine to operate at speeds below normal range. Low speeds are precisely regulated by a servomechanism as are normal-range speeds. Addition of module to standard welding machine makes it unnecessary to purchase new equipment for low-speed welding.

  5. Automatic Layout Design for Power Module

    SciTech Connect

    Ning, Puqi; Wang, Fei; Ngo, Khai

    2013-01-01

    The layout of power modules is one of the key points in power module design, especially for high power densities, where couplings are increased. In this paper, along with the design example, an automatic design processes by using a genetic algorithm are presented. Some practical considerations and implementations are introduced in the optimization of module layout design.

  6. Young Children's Automatic Encoding of Social Categories

    ERIC Educational Resources Information Center

    Weisman, Kara; Johnson, Marissa V.; Shutts, Kristin

    2015-01-01

    The present research investigated young children's automatic encoding of two social categories that are highly relevant to adults: gender and race. Three- to 6-year-old participants learned facts about unfamiliar target children who varied in either gender or race and were asked to remember which facts went with which targets. When participants…

  7. Automatic speech recognition in air traffic control

    NASA Technical Reports Server (NTRS)

    Karlsson, Joakim

    1990-01-01

    Automatic Speech Recognition (ASR) technology and its application to the Air Traffic Control system are described. The advantages of applying ASR to Air Traffic Control, as well as criteria for choosing a suitable ASR system are presented. Results from previous research and directions for future work at the Flight Transportation Laboratory are outlined.

  8. Automatic Assessment of 3D Modeling Exams

    ERIC Educational Resources Information Center

    Sanna, A.; Lamberti, F.; Paravati, G.; Demartini, C.

    2012-01-01

    Computer-based assessment of exams provides teachers and students with two main benefits: fairness and effectiveness in the evaluation process. This paper proposes a fully automatic evaluation tool for the Graphic and Virtual Design (GVD) curriculum at the First School of Architecture of the Politecnico di Torino, Italy. In particular, the tool is…

  9. Automatic speed control of highway traffic

    NASA Technical Reports Server (NTRS)

    Klingman, E. E.

    1973-01-01

    Vehicle control system monitors all vehicles in its range, and automatically slows down speeding vehicles by activating governor in vehicle. System determines only maximum speed; speeds below maximum are controlled by vehicle operator. Loss of transmitted signal or activation of emergency over-ride will open fuel line and return control to operator.

  10. Automatic Discrimination of Emotion from Spoken Finnish

    ERIC Educational Resources Information Center

    Toivanen, Juhani; Vayrynen, Eero; Seppanen, Tapio

    2004-01-01

    In this paper, experiments on the automatic discrimination of basic emotions from spoken Finnish are described. For the purpose of the study, a large emotional speech corpus of Finnish was collected; 14 professional actors acted as speakers, and simulated four primary emotions when reading out a semantically neutral text. More than 40 prosodic…

  11. Computer Corner: Automatic Differentiation and APL.

    ERIC Educational Resources Information Center

    Neidinger, Richard D.

    1989-01-01

    Described are several programs that enable the user to evaluate derivatives to order n of any elementary function by using the combination of automatic differentiation method and A Programming Language (APL). Programs calculating first- and higher-order derivatives are presented. Selected APL symbols are appended. (YP)

  12. Modification to Tracerlab Automatic Sample Changer

    USGS Publications Warehouse

    Flanegan, F.J.; Nelson, J.M.; Warr, J.J.

    1950-01-01

    The U.S. Geological Survey has recently modified the Tracerlab Automatic Sample Changer so that the geometry is greatly improved for counting larger low-activity samples in finely ground form. The larger sample and larger Geiger Mueller tubes allow a greater number of samples to be counted per hour with the same statistical accuracy.

  13. Experiments in Automatic Library of Congress Classification.

    ERIC Educational Resources Information Center

    Larson, Ray R.

    1992-01-01

    Presents the results of research into the automatic selection of Library of Congress Classification numbers based on the titles and subject headings in MARC records from a test database at the University of California at Berkeley Library School library. Classification clustering and matching techniques are described. (44 references) (LRW)

  14. A Semi-Automatic Variability Search

    NASA Astrophysics Data System (ADS)

    Maciejewski, G.; Niedzielski, A.

    Technical features of the Semi-Automatic Variability Search (SAVS) operating at the Astronomical Observatory of the Nicolaus Copernicus University and the results of the first year of observations are presented. The user-friendly software developed for reduction of acquired CCD images and detection of new variable stars is also described.

  15. 49 CFR 236.750 - Interlocking, automatic.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ..., MAINTENANCE, AND REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Definitions § 236.750 Interlocking, automatic. An arrangement of signals, with or without other signal appliances, which functions... manually, and which are so interconnected by means of electric circuits that their movements must...

  16. Do We Process Frequency Information Automatically?

    ERIC Educational Resources Information Center

    Foley, Mary Ann; Foley, Hugh J.

    Two criteria for the automatic encoding of learning, instructional manipulation, and stimulus characteristics were studied in subjects who judged the frequency of occurrence of words, letters, and nonwords. In Experiment 1, six word lists were constructed with varying frequency of alphabet letters. A variety of instructions were presented (whether…

  17. Automatic TLI recognition system, general description

    SciTech Connect

    Lassahn, G.D.

    1997-02-01

    This report is a general description of an automatic target recognition system developed at the Idaho National Engineering Laboratory for the Department of Energy. A user`s manual is a separate volume, Automatic TLI Recognition System, User`s Guide, and a programmer`s manual is Automatic TLI Recognition System, Programmer`s Guide. This system was designed as an automatic target recognition system for fast screening of large amounts of multi-sensor image data, based on low-cost parallel processors. This system naturally incorporates image data fusion, and it gives uncertainty estimates. It is relatively low cost, compact, and transportable. The software is easily enhanced to expand the system`s capabilities, and the hardware is easily expandable to increase the system`s speed. In addition to its primary function as a trainable target recognition system, this is also a versatile, general-purpose tool for image manipulation and analysis, which can be either keyboard-driven or script-driven. This report includes descriptions of three variants of the computer hardware, a description of the mathematical basis if the training process, and a description with examples of the system capabilities.

  18. Automatic Memory Processes in Mentally Retarded Persons.

    ERIC Educational Resources Information Center

    Stein, Debra Kosteski; And Others

    Automatic memory processes were investigated in 10 mild and moderately retarded persons (21 years old) and in 10 chronological age-matched college level and 10 mental age-matched elementary grade control subjects through use of a frequency estimation task. This task required the subjects to view a series of slides, then estimate how many times…

  19. Automatic TLI recognition system beta prototype testing

    SciTech Connect

    Lassahn, G.D.

    1996-06-01

    This report describes the beta prototype automatic target recognition system ATR3, and some performance tests done with this system. This is a fully operational system, with a high computational speed. It is useful for findings any kind of target in digitized image data, and as a general purpose image analysis tool.

  20. What is automatized during perceptual categorization?

    PubMed

    Roeder, Jessica L; Ashby, F Gregory

    2016-09-01

    An experiment is described that tested whether stimulus-response associations or an abstract rule are automatized during extensive practice at perceptual categorization. Twenty-seven participants each completed 12,300 trials of perceptual categorization, either on rule-based (RB) categories that could be learned explicitly or information-integration (II) categories that required procedural learning. Each participant practiced predominantly on a primary category structure, but every third session they switched to a secondary structure that used the same stimuli and responses. Half the stimuli retained their same response on the primary and secondary categories (the congruent stimuli) and half switched responses (the incongruent stimuli). Several results stood out. First, performance on the primary categories met the standard criteria of automaticity by the end of training. Second, for the primary categories in the RB condition, accuracy and response time (RT) were identical on congruent and incongruent stimuli. In contrast, for the primary II categories, accuracy was higher and RT was lower for congruent than for incongruent stimuli. These results are consistent with the hypothesis that rules are automatized in RB tasks, whereas stimulus-response associations are automatized in II tasks. A cognitive neuroscience theory is proposed that accounts for these results.

  1. Automatic Frequency Control For DMSK Receiver

    NASA Technical Reports Server (NTRS)

    Davarian, Faramaz; Sumida, Joe T.

    1989-01-01

    Report discusses performance of automatic frequency-control (AFC) subsystem of differential minimum-shift-keying receiver described in "DMSK Receiver for Moblile/Satellite Service," NPO-16659. Describes efforts to quantify behavior of system during acquisition of carrier signal; including theoretical analysis leading to numerical simulation, and measurements of performance of receiving equipment.

  2. Feedback Improvement in Automatic Program Evaluation Systems

    ERIC Educational Resources Information Center

    Skupas, Bronius

    2010-01-01

    Automatic program evaluation is a way to assess source program files. These techniques are used in learning management environments, programming exams and contest systems. However, use of automated program evaluation encounters problems: some evaluations are not clear for the students and the system messages do not show reasons for lost points.…

  3. A Statistical Approach to Automatic Speech Summarization

    NASA Astrophysics Data System (ADS)

    Hori, Chiori; Furui, Sadaoki; Malkin, Rob; Yu, Hua; Waibel, Alex

    2003-12-01

    This paper proposes a statistical approach to automatic speech summarization. In our method, a set of words maximizing a summarization score indicating the appropriateness of summarization is extracted from automatically transcribed speech and then concatenated to create a summary. The extraction process is performed using a dynamic programming (DP) technique based on a target compression ratio. In this paper, we demonstrate how an English news broadcast transcribed by a speech recognizer is automatically summarized. We adapted our method, which was originally proposed for Japanese, to English by modifying the model for estimating word concatenation probabilities based on a dependency structure in the original speech given by a stochastic dependency context free grammar (SDCFG). We also propose a method of summarizing multiple utterances using a two-level DP technique. The automatically summarized sentences are evaluated by summarization accuracy based on a comparison with a manual summary of speech that has been correctly transcribed by human subjects. Our experimental results indicate that the method we propose can effectively extract relatively important information and remove redundant and irrelevant information from English news broadcasts.

  4. Automatic optometer operates with infrared test pattern

    NASA Technical Reports Server (NTRS)

    Cornsweet, T. N.; Crane, H. D.

    1970-01-01

    Refractive strength of human eye is monitored by optometer that automatically and continuously images infrared test pattern onto the retina. Condition of focus of the eye at any instant is determined from optometer settings needed to maintain focus of the pattern on the retina.

  5. Automatic multidiagnosis system for slit lamp

    NASA Astrophysics Data System (ADS)

    Ventura, Liliane; Chiaradia, Caio; Vieira Messias, Andre M.; Faria de Sousa, Sidney J.; Isaac, Flavio; Caetano, Cesar A. C.; Rosa Filho, Andre B.

    2001-06-01

    We have developed a system for several automatic diagnose in Slit Lamp in order to provide 04 additional measurements to the biomicroscope: (1) counting of the endothelial cells of donated corneas; (2) automatic keratometry; (3) corneal ulcer evaluation; (4) measurement of linear distances and areas of the ocular image. The system consists in a Slit Lamp, a beam-splitter, some optical components, a CCD detector, a frame grabber and a PC. The optical components attached to the beam-splitter are the same for all the functions, except for 1. For function 1, we have developed an optical system that magnifies the image 290X and a software that counts the cells interactively and automatically. Results are in good agreement with commercial specular microscopes (correlation coefficient is 0,98081). The automatic keratometry function is able to measure cylinders over 30 di and also irregular astigmatisms. The system consists of projecting a light ring at the patient's cornea and the further analysis of the deformation of the ring provides the radius of curvature as well as the axis of the astigmatism. The nominal precision is 0,005 mm for the curvature radius and 2 degree(s) for the axis component. The results are in good agreement with commercial systems (correlation coefficient of 0,99347). For function 3, the ulcer is isolated by the usual clinical ways and the image of the green area is automatically detected by the developed software in order to evaluate the evolution of the disease. Function 4 simply allows the clinician do any linear or area measurement of the ocular image. The system is a low cost multi evaluation equipment and it is being used in a public hospital in Brazil.

  6. Automatic River Network Extraction from LIDAR Data

    NASA Astrophysics Data System (ADS)

    Maderal, E. N.; Valcarcel, N.; Delgado, J.; Sevilla, C.; Ojeda, J. C.

    2016-06-01

    National Geographic Institute of Spain (IGN-ES) has launched a new production system for automatic river network extraction for the Geospatial Reference Information (GRI) within hydrography theme. The goal is to get an accurate and updated river network, automatically extracted as possible. For this, IGN-ES has full LiDAR coverage for the whole Spanish territory with a density of 0.5 points per square meter. To implement this work, it has been validated the technical feasibility, developed a methodology to automate each production phase: hydrological terrain models generation with 2 meter grid size and river network extraction combining hydrographic criteria (topographic network) and hydrological criteria (flow accumulation river network), and finally the production was launched. The key points of this work has been managing a big data environment, more than 160,000 Lidar data files, the infrastructure to store (up to 40 Tb between results and intermediate files), and process; using local virtualization and the Amazon Web Service (AWS), which allowed to obtain this automatic production within 6 months, it also has been important the software stability (TerraScan-TerraSolid, GlobalMapper-Blue Marble , FME-Safe, ArcGIS-Esri) and finally, the human resources managing. The results of this production has been an accurate automatic river network extraction for the whole country with a significant improvement for the altimetric component of the 3D linear vector. This article presents the technical feasibility, the production methodology, the automatic river network extraction production and its advantages over traditional vector extraction systems.

  7. Leg automaticity is stronger than arm automaticity during simultaneous arm and leg cycling.

    PubMed

    Sakamoto, Masanori; Tazoe, Toshiki; Nakajima, Tsuyoshi; Endoh, Takashi; Komiyama, Tomoyoshi

    2014-04-03

    Recent studies indicate that human locomotion is quadrupedal in nature. An automatic rhythm-generating system is thought to play a crucial role in controlling arm and leg movements. In the present study, we attempted to elucidate differences between intrinsic arm and leg automaticity by investigating cadence variability during simultaneous arm and leg (AL) cycling. Participants performed AL cycling with visual feedback of arm or leg cadence. Participants were asked to focus their attention to match the predetermined cadence; this affects the automaticity of the rhythm-generating system. Leg cadence variability was only mildly affected when the participants intended to precisely adjust either their arm or leg cycling cadence to a predetermined value. In contrast, arm cadence variability significantly increased when the participants adjusted their leg cycling cadence to a predetermined value. These findings suggest that different neural mechanisms underlie the automaticities of arm and leg cycling and that the latter is stronger than the former during AL cycling.

  8. Entropy analysis of automatic sequences revisited: An entropy diagnostic for automaticity

    NASA Astrophysics Data System (ADS)

    Karamanos, Kostas

    2001-06-01

    We give a necessary entropy condition, valid for all automatic sequences read by lumping. We next establish new entropic decimation schemes for the Thue-Morse, the Rudin-Shapiro and the paperfolding sequences read by lumping.

  9. Using automatic programming for simulating reliability network models

    NASA Technical Reports Server (NTRS)

    Tseng, Fan T.; Schroer, Bernard J.; Zhang, S. X.; Wolfsberger, John W.

    1988-01-01

    This paper presents the development of an automatic programming system for assisting modelers of reliability networks to define problems and then automatically generate the corresponding code in the target simulation language GPSS/PC.

  10. Chemical etching for automatic processing of integrated circuits

    NASA Technical Reports Server (NTRS)

    Kennedy, B. W.

    1981-01-01

    Chemical etching for automatic processing of integrated circuits is discussed. The wafer carrier and loading from a receiving air track into automatic furnaces and unloading onto a sending air track are included.

  11. 2. FRONT VIEW, TWO DOUBLE AUTOMATIC BLOCK SIGNALS, EASTBOUND ON ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    2. FRONT VIEW, TWO DOUBLE AUTOMATIC BLOCK SIGNALS, EASTBOUND ON CATENARY BRIDGE 486 - New York, New Haven & Hartford Railroad, Automatic Signalization System, Long Island Sound shoreline between Stamford & New Haven, Stamford, Fairfield County, CT

  12. 4. OBLIQUE VIEW, AUTOMATIC BLOCK SIGNAL, EASTBOUND ON CATENARY BRIDGE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    4. OBLIQUE VIEW, AUTOMATIC BLOCK SIGNAL, EASTBOUND ON CATENARY BRIDGE 486 - New York, New Haven & Hartford Railroad, Automatic Signalization System, Long Island Sound shoreline between Stamford & New Haven, Stamford, Fairfield County, CT

  13. 1. FRONT VIEW, AUTOMATIC BLOCK SIGNAL, EASTBOUND ON CATENARY BRIDGE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. FRONT VIEW, AUTOMATIC BLOCK SIGNAL, EASTBOUND ON CATENARY BRIDGE 486 - New York, New Haven & Hartford Railroad, Automatic Signalization System, Long Island Sound shoreline between Stamford & New Haven, Stamford, Fairfield County, CT

  14. 3. REAR VIEW, AUTOMATIC BLOCK SIGNAL, EASTBOUND ON CATENARY BRIDGE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    3. REAR VIEW, AUTOMATIC BLOCK SIGNAL, EASTBOUND ON CATENARY BRIDGE 486 - New York, New Haven & Hartford Railroad, Automatic Signalization System, Long Island Sound shoreline between Stamford & New Haven, Stamford, Fairfield County, CT

  15. Semi-automatic Segmentation for Prostate Interventions

    PubMed Central

    Mahdavi, S. Sara; Chng, Nick; Spadinger, Ingrid; Morris, William J.; Salcudean, Septimiu E.

    2011-01-01

    In this paper we report and characterize a semi-automatic prostate segmentation method for prostate brachytherapy. Based on anatomical evidence and requirements of the treatment procedure, a warped and tapered ellipsoid was found suitable as the a priori 3D shape of the prostate. By transforming the acquired endorectal transverse images of the prostate into ellipses, the shape fitting problem was cast into a convex problem which can be solved efficiently. The average whole gland error between volumes created from manual and semi-automatic contours from 21 patients was 6.63±0.9%. For use in brachytherapy treatment planning, the resulting contours were modified, if deemed necessary, by radiation oncologists prior to treatment. The average whole gland volume error between the volumes computed from semi-automatic contours and those computed from modified contours, from 40 patients, was 5.82±4.15%. The amount of bias in the physicians’ delineations when given an initial semi-automatic contour was measured by comparing the volume error between 10 prostate volumes computed from manual contours with those of modified contours. This error was found to be 7.25±0.39% for the whole gland. Automatic contouring reduced subjectivity, as evidenced by a decrease in segmentation inter- and intra-observer variability from 4.65% and 5.95% for manual segmentation to 3.04% and 3.48% for semi-automatic segmentation, respectively. We characterized the performance of the method relative to the reference obtained from manual segmentation by using a novel approach that divides the prostate region into nine sectors. We analyzed each sector independently as the requirements for segmentation accuracy depend on which region of the prostate is considered. The measured segmentation time is 14±1 seconds with an additional 32±14 seconds for initialization. By assuming 1–3 minutes for modification of the contours, if necessary, a total segmentation time of less than 4 minutes is required

  16. 29 CFR 1910.159 - Automatic sprinkler systems.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... drainage facilities. (4) Water supplies. The employer shall assure that every automatic sprinkler system is provided with at least one automatic water supply capable of providing design water flow for at least 30 minutes. An auxiliary water supply or equivalent protection shall be provided when the automatic...

  17. 29 CFR 1910.159 - Automatic sprinkler systems.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... drainage facilities. (4) Water supplies. The employer shall assure that every automatic sprinkler system is provided with at least one automatic water supply capable of providing design water flow for at least 30 minutes. An auxiliary water supply or equivalent protection shall be provided when the automatic...

  18. 29 CFR 1910.159 - Automatic sprinkler systems.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... drainage facilities. (4) Water supplies. The employer shall assure that every automatic sprinkler system is provided with at least one automatic water supply capable of providing design water flow for at least 30 minutes. An auxiliary water supply or equivalent protection shall be provided when the automatic...

  19. 29 CFR 1910.159 - Automatic sprinkler systems.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... drainage facilities. (4) Water supplies. The employer shall assure that every automatic sprinkler system is provided with at least one automatic water supply capable of providing design water flow for at least 30 minutes. An auxiliary water supply or equivalent protection shall be provided when the automatic...

  20. 30 CFR 77.1401 - Automatic controls and brakes.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Automatic controls and brakes. 77.1401 Section... MINES Personnel Hoisting § 77.1401 Automatic controls and brakes. Hoists and elevators shall be equipped with overspeed, overwind, and automatic stop controls and with brakes capable of stopping the...

  1. 46 CFR 78.47-53 - Automatic ventilation dampers.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 3 2010-10-01 2010-10-01 false Automatic ventilation dampers. 78.47-53 Section 78.47-53... Fire and Emergency Equipment, Etc. § 78.47-53 Automatic ventilation dampers. (a) The manual operating positions for automatic fire dampers in ventilation ducts passing through main vertical zone bulkheads...

  2. 46 CFR 78.47-53 - Automatic ventilation dampers.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 3 2013-10-01 2013-10-01 false Automatic ventilation dampers. 78.47-53 Section 78.47-53... Fire and Emergency Equipment, Etc. § 78.47-53 Automatic ventilation dampers. (a) The manual operating positions for automatic fire dampers in ventilation ducts passing through main vertical zone bulkheads...

  3. 46 CFR 78.47-53 - Automatic ventilation dampers.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 3 2011-10-01 2011-10-01 false Automatic ventilation dampers. 78.47-53 Section 78.47-53... Fire and Emergency Equipment, Etc. § 78.47-53 Automatic ventilation dampers. (a) The manual operating positions for automatic fire dampers in ventilation ducts passing through main vertical zone bulkheads...

  4. 46 CFR 78.47-53 - Automatic ventilation dampers.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 3 2014-10-01 2014-10-01 false Automatic ventilation dampers. 78.47-53 Section 78.47-53... Fire and Emergency Equipment, Etc. § 78.47-53 Automatic ventilation dampers. (a) The manual operating positions for automatic fire dampers in ventilation ducts passing through main vertical zone bulkheads...

  5. 46 CFR 78.47-53 - Automatic ventilation dampers.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 3 2012-10-01 2012-10-01 false Automatic ventilation dampers. 78.47-53 Section 78.47-53... Fire and Emergency Equipment, Etc. § 78.47-53 Automatic ventilation dampers. (a) The manual operating positions for automatic fire dampers in ventilation ducts passing through main vertical zone bulkheads...

  6. 30 CFR 57.19006 - Automatic hoist braking devices.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Automatic hoist braking devices. 57.19006 Section 57.19006 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND... Hoisting Hoists § 57.19006 Automatic hoist braking devices. Automatic hoists shall be provided with...

  7. 30 CFR 56.19006 - Automatic hoist braking devices.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Automatic hoist braking devices. 56.19006 Section 56.19006 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND... Hoisting Hoists § 56.19006 Automatic hoist braking devices. Automatic hoists shall be provided with...

  8. 30 CFR 75.1103 - Automatic fire warning devices.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Automatic fire warning devices. 75.1103 Section... AND HEALTH MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Fire Protection § 75.1103 Automatic fire... warning automatically when a fire occurs on or near such belt. The Secretary shall prescribe a...

  9. Automatic Evaluations in Clinically Anxious and Nonanxious Children and Adolescents

    ERIC Educational Resources Information Center

    Vervoort, Leentje; Wolters, Lidewij H.; Hogendoorn, Sanne M.; Prins, Pier J. M.; de Haan, Else; Nauta, Maaike H.; Boer, Frits

    2010-01-01

    Automatic evaluations of clinically anxious and nonanxious children (n = 40, aged 8-16, 18 girls) were compared using a pictorial performance-based measure of automatic affective associations. Results showed a threat-related evaluation bias in clinically anxious but not in nonanxious children. In anxious participants, automatic evaluations of…

  10. 30 CFR 77.314 - Automatic temperature control instruments.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Automatic temperature control instruments. 77... UNDERGROUND COAL MINES Thermal Dryers § 77.314 Automatic temperature control instruments. (a) Automatic temperature control instruments for thermal dryer system shall be of the recording type. (b)...

  11. 30 CFR 77.314 - Automatic temperature control instruments.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Automatic temperature control instruments. 77... UNDERGROUND COAL MINES Thermal Dryers § 77.314 Automatic temperature control instruments. (a) Automatic temperature control instruments for thermal dryer system shall be of the recording type. (b)...

  12. 30 CFR 77.314 - Automatic temperature control instruments.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Automatic temperature control instruments. 77... UNDERGROUND COAL MINES Thermal Dryers § 77.314 Automatic temperature control instruments. (a) Automatic temperature control instruments for thermal dryer system shall be of the recording type. (b)...

  13. 30 CFR 77.314 - Automatic temperature control instruments.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Automatic temperature control instruments. 77... UNDERGROUND COAL MINES Thermal Dryers § 77.314 Automatic temperature control instruments. (a) Automatic temperature control instruments for thermal dryer system shall be of the recording type. (b)...

  14. 30 CFR 77.314 - Automatic temperature control instruments.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Automatic temperature control instruments. 77... UNDERGROUND COAL MINES Thermal Dryers § 77.314 Automatic temperature control instruments. (a) Automatic temperature control instruments for thermal dryer system shall be of the recording type. (b)...

  15. 5 CFR 831.502 - Automatic separation; exemption.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 5 Administrative Personnel 2 2013-01-01 2013-01-01 false Automatic separation; exemption. 831.502... REGULATIONS (CONTINUED) RETIREMENT Eligibility for Retirement § 831.502 Automatic separation; exemption. (a... automatic separation at the end of that month. The department or agency shall notify the employee of...

  16. 5 CFR 831.502 - Automatic separation; exemption.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 5 Administrative Personnel 2 2012-01-01 2012-01-01 false Automatic separation; exemption. 831.502... REGULATIONS (CONTINUED) RETIREMENT Eligibility for Retirement § 831.502 Automatic separation; exemption. (a... automatic separation at the end of that month. The department or agency shall notify the employee of...

  17. 5 CFR 831.502 - Automatic separation; exemption.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 5 Administrative Personnel 2 2011-01-01 2011-01-01 false Automatic separation; exemption. 831.502... REGULATIONS (CONTINUED) RETIREMENT Eligibility for Retirement § 831.502 Automatic separation; exemption. (a... automatic separation at the end of that month. The department or agency shall notify the employee of...

  18. 5 CFR 831.502 - Automatic separation; exemption.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 5 Administrative Personnel 2 2010-01-01 2010-01-01 false Automatic separation; exemption. 831.502... REGULATIONS (CONTINUED) RETIREMENT Eligibility for Retirement § 831.502 Automatic separation; exemption. (a... automatic separation at the end of that month. The department or agency shall notify the employee of...

  19. 5 CFR 831.502 - Automatic separation; exemption.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 5 Administrative Personnel 2 2014-01-01 2014-01-01 false Automatic separation; exemption. 831.502... REGULATIONS (CONTINUED) RETIREMENT Eligibility for Retirement § 831.502 Automatic separation; exemption. (a... automatic separation at the end of that month. The department or agency shall notify the employee of...

  20. Automaticity of walking: functional significance, mechanisms, measurement and rehabilitation strategies

    PubMed Central

    Clark, David J.

    2015-01-01

    Automaticity is a hallmark feature of walking in adults who are healthy and well-functioning. In the context of walking, “automaticity” refers to the ability of the nervous system to successfully control typical steady state walking with minimal use of attention-demanding executive control resources. Converging lines of evidence indicate that walking deficits and disorders are characterized in part by a shift in the locomotor control strategy from healthy automaticity to compensatory executive control. This is potentially detrimental to walking performance, as an executive control strategy is not optimized for locomotor control. Furthermore, it places excessive demands on a limited pool of executive reserves. The result is compromised ability to perform basic and complex walking tasks and heightened risk for adverse mobility outcomes including falls. Strategies for rehabilitation of automaticity are not well defined, which is due to both a lack of systematic research into the causes of impaired automaticity and to a lack of robust neurophysiological assessments by which to gauge automaticity. These gaps in knowledge are concerning given the serious functional implications of compromised automaticity. Therefore, the objective of this article is to advance the science of automaticity of walking by consolidating evidence and identifying gaps in knowledge regarding: (a) functional significance of automaticity; (b) neurophysiology of automaticity; (c) measurement of automaticity; (d) mechanistic factors that compromise automaticity; and (e) strategies for rehabilitation of automaticity. PMID:25999838

  1. 21 CFR 892.1900 - Automatic radiographic film processor.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Automatic radiographic film processor. 892.1900... (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1900 Automatic radiographic film processor. (a) Identification. An automatic radiographic film processor is a device intended to be used...

  2. 21 CFR 892.1900 - Automatic radiographic film processor.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Automatic radiographic film processor. 892.1900... (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1900 Automatic radiographic film processor. (a) Identification. An automatic radiographic film processor is a device intended to be used...

  3. 21 CFR 892.1900 - Automatic radiographic film processor.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Automatic radiographic film processor. 892.1900... (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1900 Automatic radiographic film processor. (a) Identification. An automatic radiographic film processor is a device intended to be used...

  4. 21 CFR 892.1900 - Automatic radiographic film processor.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Automatic radiographic film processor. 892.1900... (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1900 Automatic radiographic film processor. (a) Identification. An automatic radiographic film processor is a device intended to be used...

  5. 21 CFR 892.1900 - Automatic radiographic film processor.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Automatic radiographic film processor. 892.1900... (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1900 Automatic radiographic film processor. (a) Identification. An automatic radiographic film processor is a device intended to be used...

  6. The Use of Automatic Indexing for Authority Control.

    ERIC Educational Resources Information Center

    Dillon, Martin; And Others

    1981-01-01

    Uses an experimental system for authority control on a collection of bibliographic records to demonstrate the resemblance between thesaurus-based automatic indexing and automatic authority control. Details of the automatic indexing system are given, results discussed, and the benefits of the resemblance examined. Included are a rules appendix and…

  7. Automatic mathematical modeling for real time simulation program (AI application)

    NASA Technical Reports Server (NTRS)

    Wang, Caroline; Purinton, Steve

    1989-01-01

    A methodology is described for automatic mathematical modeling and generating simulation models. The major objective was to create a user friendly environment for engineers to design, maintain, and verify their models; to automatically convert the mathematical models into conventional code for computation; and finally, to document the model automatically.

  8. Automatic TLI recognition system, user`s guide

    SciTech Connect

    Lassahn, G.D.

    1997-02-01

    This report describes how to use an automatic target recognition system (version 14). In separate volumes are a general description of the ATR system, Automatic TLI Recognition System, General Description, and a programmer`s manual, Automatic TLI Recognition System, Programmer`s Guide.

  9. 14 CFR 171.263 - Localizer automatic monitor system.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 3 2011-01-01 2011-01-01 false Localizer automatic monitor system. 171.263... System (ISMLS) § 171.263 Localizer automatic monitor system. (a) The ISMLS localizer equipment must provide an automatic monitor system that transmits a warning to designated local and remote control...

  10. 14 CFR 171.263 - Localizer automatic monitor system.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 3 2012-01-01 2012-01-01 false Localizer automatic monitor system. 171.263... System (ISMLS) § 171.263 Localizer automatic monitor system. (a) The ISMLS localizer equipment must provide an automatic monitor system that transmits a warning to designated local and remote control...

  11. 14 CFR 171.263 - Localizer automatic monitor system.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 3 2014-01-01 2014-01-01 false Localizer automatic monitor system. 171.263... System (ISMLS) § 171.263 Localizer automatic monitor system. (a) The ISMLS localizer equipment must provide an automatic monitor system that transmits a warning to designated local and remote control...

  12. 14 CFR 171.263 - Localizer automatic monitor system.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 3 2013-01-01 2013-01-01 false Localizer automatic monitor system. 171.263... System (ISMLS) § 171.263 Localizer automatic monitor system. (a) The ISMLS localizer equipment must provide an automatic monitor system that transmits a warning to designated local and remote control...

  13. 30 CFR 56.19006 - Automatic hoist braking devices.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Automatic hoist braking devices. 56.19006 Section 56.19006 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND... Hoisting Hoists § 56.19006 Automatic hoist braking devices. Automatic hoists shall be provided with...

  14. 30 CFR 57.19006 - Automatic hoist braking devices.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Automatic hoist braking devices. 57.19006 Section 57.19006 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND... Hoisting Hoists § 57.19006 Automatic hoist braking devices. Automatic hoists shall be provided with...

  15. 30 CFR 57.19006 - Automatic hoist braking devices.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Automatic hoist braking devices. 57.19006 Section 57.19006 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND... Hoisting Hoists § 57.19006 Automatic hoist braking devices. Automatic hoists shall be provided with...

  16. 30 CFR 56.19006 - Automatic hoist braking devices.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Automatic hoist braking devices. 56.19006 Section 56.19006 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND... Hoisting Hoists § 56.19006 Automatic hoist braking devices. Automatic hoists shall be provided with...

  17. 30 CFR 56.19006 - Automatic hoist braking devices.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Automatic hoist braking devices. 56.19006 Section 56.19006 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND... Hoisting Hoists § 56.19006 Automatic hoist braking devices. Automatic hoists shall be provided with...

  18. 30 CFR 57.19006 - Automatic hoist braking devices.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Automatic hoist braking devices. 57.19006 Section 57.19006 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND... Hoisting Hoists § 57.19006 Automatic hoist braking devices. Automatic hoists shall be provided with...

  19. 30 CFR 57.19006 - Automatic hoist braking devices.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Automatic hoist braking devices. 57.19006 Section 57.19006 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND... Hoisting Hoists § 57.19006 Automatic hoist braking devices. Automatic hoists shall be provided with...

  20. 30 CFR 56.19006 - Automatic hoist braking devices.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Automatic hoist braking devices. 56.19006 Section 56.19006 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND... Hoisting Hoists § 56.19006 Automatic hoist braking devices. Automatic hoists shall be provided with...