Xu, C; Wu, X; Wu, Xuejun
2004-01-01
In this paper, it is the first time to construct a complete post-Newtonian (PN) model of a rigid body by means of a new constraint on the mass current density and mass density. In our PN rigid body model most of relations, such as spin vector proportional to the angular velocity, the definition on the moment of inertia tensor, the key relation between the mass quadrupole moment and the moment of inertia tensor, rigid rotating formulae of mass quadrupole moment and the moment of inertia tensor, are just the extension of the main relations in Newtonian rigid body model. When all of $1/c^2$ terms are neglected, the PN rigid body model and the corresponding formulae reduce to Newtonian version. The key relation is obtained in this paper for the first time, which might be very useful in the future application to problems in geodynamics and astronomy.
Xu, Chongming; Tao, Jin-he; Wu, Xuejun
2003-01-01
In this paper, it is the first time to construct a complete post-Newtonian (PN) model of a rigid body by means of a new constraint on the mass current density and mass density. In our PN rigid body model most of relations, such as spin vector proportional to the angular velocity, the definition on the moment of inertia tensor, the key relation between the mass quadrupole moment and the moment of inertia tensor, rigid rotating formulae of mass quadrupole moment and the moment of inertia tensor...
DEFF Research Database (Denmark)
Niebe, Sarah Maria
The topic of this thesis is the numerics of rigid body simulation, with focus on the contact force problem. Three contact force models are presented, followed by three contact point determination methods. To solve the contact force problem, six different numerical methods are presented, each...... tailored to solve problems in the form of one of the three contact force models. The scientific contributions of this thesis, lies in part in the dissection of existing methods in which issues are uncovered and – where possible – fixes are suggested, and in part in the development of novel methods. A...... contact point determination method, based on boolean surface maps, is developed to handle collisions between tetrahedral meshes. The novel nonsmooth nonlinear conjugate gradient (NNCG) method is presented. The NNCG method is comparable in terms of accuracy to the state-of-the-art method, projected Gauss...
Rigid body dynamics of mechanisms
Hahn, Hubert
2003-01-01
The second volume of Rigid Body Dynamics of Mechanisms covers applications via a systematic method for deriving model equations of planar and spatial mechanisms. The necessary theoretical foundations have been laid in the first volume that introduces the theoretical mechanical aspects of mechatronic systems. Here the focus is on the application of the modeling methodology to various examples of rigid-body mechanisms, simple planar ones as well as more challenging spatial problems. A rich variety of joint models, active constraints, plus active and passive force elements is treated. The book is intended for self-study by working engineers and students concerned with the control of mechanical systems, i.e. robotics, mechatronics, vehicles, and machine tools. The examples included are a likely source from which to choose models for university lectures.
Real-Time Rigid Body Interactions
Fossum, Fredrik
2011-01-01
Rigid body simulations are useful in many areas, most notably video games and computer animation.However, the requirements for accuracy and performance vary greatly between applications.In this project we combine methods and techniques from different sources to implement a rigid body simulation.The simulation uses a particle representation to approximate objects with the intent of reaching better performance at the cost of accuracy.We simulate cubes in order to showcase the behavior of our si...
Quantum mechanics of a generalised rigid body
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.
Quantum mechanics of a generalised rigid body
Gripaios, Ben
2015-01-01
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. 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.
Understanding rigid body motion in arbitrary dimensions
Leyvraz, Francois
2014-01-01
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 specifically three-dimensional constructs is actually easier to grasp than the traditional one 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 equation of motion for ...
The theory of pseudo-rigid bodies
Cohen, Harley
1988-01-01
This monograph concerns the development, analysis, and application of the theory of pseudo-rigid bodies. It collects together our work on that subject over the last five years. While some results have appeared else where, much of the work is new. Our objective in writing this mono graph has been to present a new theory of the deformation of bodies, one that has not only a firm theoretical basis, but also the simplicity to serve as an effective tool in practical problems. Consequently, the main body of the treatise is a multifaceted development of the theory, from foundations to explicit solutions to linearizations to methods of approximation. The fact that this variety of aspects, each examined in considerable detail, can be collected together in a single, unified treat ment gives this theory an elegance that we feel sets it apart from many others. While our goal has always been to give a complete treatment of the theory as it now stands, the work here is not meant to be definitive. Theories are not ent...
Stability of rigid body rotation from a bond graph perspective
Breedveld, Peter
2009-01-01
This paper describes the history of the bond graph description of rigid body rotation dynamics and resolves a paradox that resulted from the common Euler Junction Structure (EJS) description of the exterior product in the Newton–Euler equation describing rigid body rotation [D.C. Karnopp, R.C. Rosen
Brownian dynamics of confined rigid bodies
Energy Technology Data Exchange (ETDEWEB)
Delong, Steven; Balboa Usabiaga, Florencio; Donev, Aleksandar, E-mail: donev@courant.nyu.edu [Courant Institute of Mathematical Sciences, New York University, New York, New York 10012 (United States)
2015-10-14
We introduce numerical methods for simulating the diffusive motion of rigid bodies of arbitrary shape immersed in a viscous fluid. We parameterize the orientation of the bodies using normalized quaternions, which are numerically robust, space efficient, and easy to accumulate. We construct a system of overdamped Langevin equations in the quaternion representation that accounts for hydrodynamic effects, preserves the unit-norm constraint on the quaternion, and is time reversible with respect to the Gibbs-Boltzmann distribution at equilibrium. We introduce two schemes for temporal integration of the overdamped Langevin equations of motion, one based on the Fixman midpoint method and the other based on a random finite difference approach, both of which ensure that the correct stochastic drift term is captured in a computationally efficient way. We study several examples of rigid colloidal particles diffusing near a no-slip boundary and demonstrate the importance of the choice of tracking point on the measured translational mean square displacement (MSD). We examine the average short-time as well as the long-time quasi-two-dimensional diffusion coefficient of a rigid particle sedimented near a bottom wall due to gravity. For several particle shapes, we find a choice of tracking point that makes the MSD essentially linear with time, allowing us to estimate the long-time diffusion coefficient efficiently using a Monte Carlo method. However, in general, such a special choice of tracking point does not exist, and numerical techniques for simulating long trajectories, such as the ones we introduce here, are necessary to study diffusion on long time scales.
Brownian dynamics of confined rigid bodies
Delong, Steven; Balboa Usabiaga, Florencio; Donev, Aleksandar
2015-10-01
We introduce numerical methods for simulating the diffusive motion of rigid bodies of arbitrary shape immersed in a viscous fluid. We parameterize the orientation of the bodies using normalized quaternions, which are numerically robust, space efficient, and easy to accumulate. We construct a system of overdamped Langevin equations in the quaternion representation that accounts for hydrodynamic effects, preserves the unit-norm constraint on the quaternion, and is time reversible with respect to the Gibbs-Boltzmann distribution at equilibrium. We introduce two schemes for temporal integration of the overdamped Langevin equations of motion, one based on the Fixman midpoint method and the other based on a random finite difference approach, both of which ensure that the correct stochastic drift term is captured in a computationally efficient way. We study several examples of rigid colloidal particles diffusing near a no-slip boundary and demonstrate the importance of the choice of tracking point on the measured translational mean square displacement (MSD). We examine the average short-time as well as the long-time quasi-two-dimensional diffusion coefficient of a rigid particle sedimented near a bottom wall due to gravity. For several particle shapes, we find a choice of tracking point that makes the MSD essentially linear with time, allowing us to estimate the long-time diffusion coefficient efficiently using a Monte Carlo method. However, in general, such a special choice of tracking point does not exist, and numerical techniques for simulating long trajectories, such as the ones we introduce here, are necessary to study diffusion on long time scales.
A Concise Introduction to Mechanics of Rigid Bodies Multidisciplinary Engineering
Huang, L
2012-01-01
A Concise Introduction to Mechanics of Rigid Bodies: Multidisciplinary Engineering presents concise, key concepts of kinematics and dynamics of rigid bodies. This compact volume bridges the steep gap between introductory texts on engineering mechanics, which focus on one and two dimensional motions of particles and rigid bodies, and advanced texts on multi-body dynamics in high dimension spaces found in multidisciplinary areas like mechatronics, robotics and biomechanics. In the book, rigid body motions in the spaces with different dimensions are described in addition to studies in a uniform framework supported by vector and matrix operations. Rigorous mathematic tools and explanations are provided to clarify the most complex concepts. This book also: Provides practical examples from different engineering areas, offering a link between theoretical fundamentals and everyday applications Offers simplified mathematical equations to clearly present essential theories in robotics and mechanics Presents statics...
Tautochrone and Brachistochrone Shape Solutions for Rocking Rigid Bodies
Glaschke, Patrick
2016-01-01
Rocking rigid bodies appear in several shapes in everyday life: As furniture like rocking chairs and rocking cradles or as toys like rocking horses or tilting dolls. The familiar rocking motion of these objects, a non-linear combination of a rigid rotation and a translation of the center of mass, gives rise to a number of interesting dynamical properties. However, their study has received little attention in the literature. This work presents a comprehensive introduction to the dynamics of rocking rigid bodies, including a concise derivation of the equations of motion as well as a general inversion procedure to construct rocking rigid body shapes with specified dynamical properties. Moreover, two novel rigid body shapes are derived - the tautochrone shape and the brachistochrone shape - which represent an intriguing generalization of the well-know tautochrone and brachistochrone curves. In particular, tautochrone shapes offer an alternative construction of a tautochrone pendulum, in addition to Huygens' cyclo...
Propagation of Uncertainty in Rigid Body Attitude Flows
Lee, Taeyoung; Chaturvedi, Nalin A.; Sanyal, Amit K.; Leok, Melvin; McClamroch, N. Harris
2007-01-01
Motivated by attitude control and attitude estimation problems for a rigid body, computational methods are proposed to propagate uncertainties in the angular velocity and the attitude. The nonlinear attitude flow is determined by Euler-Poincar\\'e equations that describe the rotational dynamics of the rigid body acting under the influence of an attitude dependent potential and by a reconstruction equation that describes the kinematics expressed in terms of an orthogonal matrix representing the...
On the inertial motions of liquid-filled rigid bodies
Mazzone, Giusy; Galdi, Giovanni; Zunino, Paolo
2013-11-01
We consider a rigid body with a cavity completely filled by a viscous liquid and study the inertial motions of the system liquid-filled rigid body S . The equations governing the motion of this coupled system are given by the Navier-Stokes equations and the equations of the balance of the total angular momentum of S in absence of external forces and torques. Given any initial motion to the coupled system, characterized by an initial relative velocity of the fluid and an initial total angular momentum, we give a complete description of the behavior that the system liquid-filled rigid body will show at large times. From both analytical and numerical viewpoints, we are able to prove a longstanding conjecture stated by Zhukovskii, namely that S will eventually reach a steady state which is a rigid body permanent rotation. In other words, the liquid goes to rest with respect to the rigid body and the coupled system will rotate as a whole rigid body, with a constant angular velocity that is directed along one of the principal axes of inertia of the system.
Rigid multibody system dynamics with uncertain rigid bodies
International Nuclear Information System (INIS)
This paper is devoted to the construction of a probabilistic model of uncertain rigid bodies for multibody system dynamics. We first construct a stochastic model of an uncertain rigid body by replacing the mass, the center of mass, and the tensor of inertia by random variables. The prior probability distributions of the stochastic model are constructed using the maximum entropy principle under the constraints defined by the available information. The generators of independent realizations corresponding to the prior probability distribution of these random quantities are further developed. Then several uncertain rigid bodies can be linked to each other in order to calculate the random response of a multibody dynamical system. An application is proposed to illustrate the theoretical development.
Kinematic Control of Free Rigid Bodies Using Dual Quaternions
Institute of Scientific and Technical Information of China (English)
Da-Peng Han; Qing Wei; Ze-Xiang Li
2008-01-01
This paper proposes a new type of control laws for free rigid bodies. The start point is the dual quaternion and its characteristics. The logarithm of a dual quaternion is defined, based on which kinematic control laws can be developed. Global exponential convergence is achieved using logarithmic feedback via a generalized proportional control law, and an appropriate Lyapunov function is constructed to prove the stability. Both the regulation and tracking problems are tackled. Omnidirectional control is discussed as a case study. As the control laws can handle the intercounection between the rotation and translation of a rigid body, they axe shown to be more applicable than the conventional method.
Global Controllability of Multidimensional Rigid Body by Few Torques
Sarychev, Andrey V
2009-01-01
We study global controllability of 'rotating' multidimensional rigid body (MRB) controlled by application of few torques. Study by methods of geometric control requires analysis of algebraic structure introduced by the quadratic term of Euler-Frahm equation. We discuss problems, which arise in the course of this analysis, and establish several global controllability criteria for damped and non damped cases.
Steady Fall of a Rigid Body in Viscous Fluid
Czech Academy of Sciences Publication Activity Database
Nečasová, Šárka
Praha : Ústav termomechaniky AV ČR, 2005 - (Příhoda, J.; Kozel, K.), s. 77-80 ISBN 80-85918-92-7. [Topical Problems of Fluid Mechanics. Prague (CZ), 25.02.2004] Institutional research plan: CEZ:AV0Z1019905 Keywords : steady fall * rigid body * viscous fluid Subject RIV: BA - General Mathematics
Impedance of rigid bodies in one-dimensional elastic collisions
Santos, Janilo; Nelson, Osman Rosso
2012-01-01
In this work we study the problem of one-dimensional elastic collisions of billiard balls, considered as rigid bodies, in a framework very different from the classical one presented in text books. Implementing the notion of impedance matching as a way to understand eficiency of energy transmission in elastic collisions, we find a solution which frames the problem in terms of this conception. We show that the mass of the ball can be seen as a measure of its impedance and verify that the problem of maximum energy transfer in elastic collisions can be thought of as a problem of impedance matching between different media. This approach extends the concept of impedance, usually associated with oscillatory systems, to system of rigid bodies.
A symmetric splitting method for rigid body dynamics
Directory of Open Access Journals (Sweden)
E. Celledoni
2006-04-01
Full Text Available It has been known since the time of Jacobi that the solution to the free rigid body (FRB equations of motion is given in terms of a certain type of elliptic functions. Using the Arithmetic-Geometric mean algorithm, (1, these functions can be calculated efficiently and accurately. The overall approach yields a faster and more accurate numerical solution to the FRB equations compared to standard numerical ODE and symplectic solvers. In this paper we investigate the possibility of extending this approach to the case of rigid bodies subject to external forces. By using a splitting strategy similar to the one proposed in (14, we decompose the vector field of our problem in a FRB problem and another completely integrable vector field. We apply the method to the simulation of the heavy top.
Steady fall of a rigid body in viscous fluid
Czech Academy of Sciences Publication Activity Database
Nečasová, Šárka
2005-01-01
Roč. 63, Sp. Is. (2005), s. 2113-2119. ISSN 0362-546X. [Invited Talks from the Fourth World Congress of Nonlinear Analysts (WCNA 2004). Orlando, 30.7.2004-7.8.2004] R&D Projects: GA ČR(CZ) GA201/02/0684 Institutional research plan: CEZ:AV0Z1019905 Keywords : steady fall * rigid body * viscous fluid Subject RIV: BA - General Mathematics Impact factor: 0.519, year: 2005
Global Exponential Angular Velocity Observer for Rigid Body Systems
Berkane, Soulaimane; Abdessameud, Abdelkader; Tayebi, Abdelhamid
2016-01-01
We present a uniformly globally exponentially stable hybrid angular velocity observer for rigid body systems designed directly on $SO(3)\\times\\mathbb{R}^3$. The global exponential stability result makes this observer a good candidate for a controller-observer combination with a guaranteed separation property. Simulation results are provided to demonstrate the effectiveness of the proposed hybrid observer as a part of an attitude stabilization scheme.
Stability of relative equilibria of multidimensional rigid body
Izosimov, Anton
2012-01-01
It is well known that a free three-dimensional rigid body admits three stationary rotations. These are the rotations around three principal axes of inertia. The rotations around the long and the short axes are stable, while the rotation around the intermediate axis is unstable. We generalize this result to the case of a multidimensional body. The stability problem is being solved for a dense subset of stationary rotations in arbitrary dimension.
Nonlinear dynamics mathematical models for rigid bodies with a liquid
Lukovsky, Ivan A
2015-01-01
This book is devoted to analytically approximate methods in the nonlinear dynamics of a rigid body with cavities partly filled by liquid. It combines several methods and compares the results with experimental data. It is useful for experienced and early-stage readers interested in analytical approaches to fluid-structure interaction problems, the fundamental mathematical background and modeling the dynamics of such complex mechanical systems.
A SYMPLECTIC ALGORITHM FOR DYNAMICS OF RIGID BODY
Institute of Scientific and Technical Information of China (English)
LU Ying-jie; REN Ge-xue
2006-01-01
For the dynamics of a rigid body with a fixed point based on the quaternion and the corresponding generalized momenta, a displacement-based symplectic integration scheme for differential-algebraic equations is proposed and applied to the Lagrange's equations based on dependent generalized momenta. Numerical experiments show that the algorithm possesses such characters as high precision and preserving system invariants.More importantly, the generalized momenta based Lagrange's equations show unique advantages over the traditional Lagrange's equations in symplectic integrations.
Failure of intuition in elementary rigid body dynamics
Lemos, Nivaldo A
2008-01-01
Suppose a projectile collides perpendicularly with a stationary rigid rod on a smooth horizontal table. We show that, contrary to what one naturally expects, it is not always the case that the rod acquires maximum angular velocity when struck at an extremity. The treatment is intended for first year university students of Physics or Engineering, and could form the basis of a tutorial discussion of conservation laws in rigid body dynamics.
Drawing the Free Rigid Body Dynamics According to Jacobi
Pina, Eduardo G
2015-01-01
Guided by the Jacobi's work published the year before his death about the rotation of a rigid body, the behavior of the rotation matrix describing the dynamics of the free rigid body is studied. To illustrate this dynamics one draws on a unit sphere the trace of the three unit vectors, in the body system along the principal directions of inertia. A minimal set of properties of Jacobi's elliptic functions are used, those which allow to compute with the necessary precision the dynamics of the rigid body without torques, the so called Euler's top. Emphasis is on the paper published by Jacobi in 1850 on the explicit expression for the components of the rotation matrix. The tool used to compute the trajectories to be drawn are the Jacobi's Fourier series for {\\sl theta} and {\\sl eta} functions with extremely fast convergence. The Jacobi's {\\sl sn}, {\\sl cn} and {\\sl dn} functions, which are better known, are used also as ratios of {\\sl theta} functions which permit quick and accurate computation. Finally the main ...
Geometry of the Motion of Ideal Fluids and Rigid Bodies
Rajeev, S G
2009-01-01
Arnold pointed out that the Euler equation of incompressible ideal hydrodynamics describes geodesics on the group of volume-preserving diffeomorphisms. A simple analogue is the Euler equation for a rigid body, which is the geodesic equation on the rotation group with respect to a metric determined by the moment of inertia. The metric on the group is left-invariant but not right-invariant. We will reduce the geometry of such groups (using techniques popularized by Milnor) to algebra on their tangent space. In particular, the curvature can be expressed as a biquadratic form on the Lie algebra. Arnold's result that motion of incompressible fluids has instabilities (due to the sectional curvature being negative) can be recovered more simply. Surprisingly, such an instability arises in rigid body mechanics as well: the metric on SO(3) corresponding to the moment of inertia of a thin cylinder (coin) has negative sectional curvature in one tangent plane. Both ideal fluids and rigid bodies can be thought of as hamilt...
Control of the rigid body and dynamics with symmetry
Lum, Kai-Yew
This dissertation explores various problems in the control of the rigid body and related dynamical systems with symmetry, utilizing various modeling approaches and control techniques. We first derive a control law that asymptotically stabilizes an unbalanced top to the sleeping motion. We rewrite the classical Euler-Poisson equations by projecting the phase space onto IRsp5. The control law is based on the Hamilton-Jacobi-Bellman theory with zero dynamics and partial stability. Lyapunov techniques are used in the analysis. Next, the control of rotor imbalance with magnetic bearings is considered in the adaptive virtual autobalancing and adaptive autocentering approaches. We derive single-plane and two-plane balancing control algorithms that provide asymptotic estimates of the rotor imbalance, and that guarantee consistent performance under varying spin rate. These algorithms are based on emulation of the mechanical autobalancer. We discuss the theory based on linear analysis, and simulation and experimental results. We go on to investigate symmetry properties associated with mechanical control systems and certain nonlinear control systems. First, we generalize the classical Serret-Andoyer transformation for the free rigid body to left-invariant, hyperregular Hamiltonian systems on Tsp*SO(3), employing the notion of symplectic (Marsden-Weinstein) reduction. We then apply this result to the controlled rigid body, and show that for Hamiltonian controls that preserve the rigid body structure, the generalized Serret-Andoyer transformation yields a two dimensional representation of the closed-loop motion in canonical form. Applications to the stability analysis of relative equilibria and numerical integration are also discussed. Finally, we apply the concept of reduction to certain regulation problems on smooth manifolds. Following the works of Van der Schaft (1981) and Grizzle and Marcus (1985), we show that an output feedback regulation problem possessing certain
Dynamic Buckling of Column Impacted by a Rigid Body
Institute of Scientific and Technical Information of China (English)
Zhijun Han; Hongwei Ma; Shanyuan Zhang
2004-01-01
The dynamic buckling of an elastic column subjected to axial impact by a rigid body is discussed in accordance with the energy law in this paper. The equation of lateral disturbance used to analysis the problem is developed by taking into account the effect of stress wave. The power series solution of this problem has been obtained by using the power series approach. The buckling criterion of this problem is proposed by analyzing the characteristics of the solution. The relationships between critical velocity and impacting mass as well as critical velocity and critical length are given by using theoretical analysis and numerical computation.
Euler-Poincare Reduction of a Rigid Body Motion
DEFF Research Database (Denmark)
Wisniewski, Rafal; Kulczycki, P.
2005-01-01
|If a mechanical system experiences symmetry, the Lagrangian becomes invariant under a certain group action. This property leads to substantial simplification of the description of movement. The standpoint in this article is a mechanical system afected by an external force of a control action...... control system generates an external force, which may break the symmetry in the dynamics. This paper shows how to model and to control a mechanical sys- tem on the reduced phase space, such that complete state space asymptotic stabilization can be achieved. The paper comprises a specialization of the well......-known Euler-Poincare reduction to a rigid body motion with forcing....
Euler-Poincare Reduction of Externall Forced Rigid Body Motion
DEFF Research Database (Denmark)
Wisniewski, Rafal; Kulczycki, P.
2004-01-01
If a mechanical system experiences symmetry, the Lagrangian becomes invariant under a certain group action. This property leads to substantial simplification of the description of movement. The standpoint in this article is a mechanical system affected by an external force of a control action...... control system generates an external force, which may break the symmetry in the dynamics. This paper shows how to model and to control a mechanical system on the reduced phase space, such that complete state space asymptotic stabilization can be achieved. The paper comprises a specialization of the well......-known Euler-Poincaré reduction to a rigid body motion with forcing....
Identification of Helicopter Rigid Body Dynamics from Flight Data.
Directory of Open Access Journals (Sweden)
Jatinder Singh
1998-01-01
Full Text Available This paper discusses helicopter modelling and identification related aspects. By applying thesystem identification methodology, longitudinal and lateral-directional rigid body helicopter dynamics are identified from flight data. Aerodynamic parameters from single input excitation as wellas multimanoeuver evaluation are estimated utilising output-error approach. The formulatedmathematical models yield adequate fit to measured time histories. Results obtained from the proof-of-match for model validation indicate that the identified derivatives can satisfactorily predictlongitudinal dynamics to a given arbitrary input. It is further demonstrated for the present study thatlateral body dynamics can be adequately predicted by including cross-coupling terms in the estimation model.
Collisions of Constrained Rigid Body Systems with Friction
Directory of Open Access Journals (Sweden)
Haijun Shen
1998-01-01
Full Text Available A new approach is developed for the general collision problem of two rigid body systems with constraints (e.g., articulated systems, such as massy linkages in which the relative tangential velocity at the point of contact and the associated friction force can change direction during the collision. This is beyond the framework of conventional methods, which can give significant and very obvious errors for this problem, and both extends and consolidates recent work. A new parameterization and theory characterize if, when and how the relative tangential velocity changes direction during contact. Elastic and dissipative phenomena and different values for static and kinetic friction coefficients are included. The method is based on the explicitly physical analysis of events at the point of contact. Using this method, Example 1 resolves (and corrects a paradox (in the literature of the collision of a double pendulum with the ground. The method fundamentally subsumes other recent models and the collision of rigid bodies; it yields the same results as conventional methods when they would apply (Example 2. The new method reformulates and extends recent approaches in a completely physical context.
A method for measuring the inertia properties of rigid bodies
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.
A new cantilever beam-rigid-body MEMS gyroscope: mathematical model and linear dynamics
Lajimi, Seyed Amir Mousavi; Abdel-Rahman, Eihab
2014-01-01
A new microbeam-rigid-body gyroscope is introduced and its static and dynamic behaviours are studied. The main structure includes a microbeam and an eccentric end-rigid-body influencing the dynamic and static characteristics of the sensor. The sensitivity of the device and the effect of system parameters on the microsystem's response are investigated.
A general purpose nonlinear rigid body mass finite element for application to rotary wing dynamics
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.
Error analysis of rigid body posture measurement system based on circular feature points
Huo, Ju; Cui, Jishan; Yang, Ning
2015-02-01
For monocular vision pose parameters determine the problem, feature-based target feature points on the plane quadrilateral, an improved two-stage iterative algorithm is proposed to improve the optimization of rigid body posture measurement calculating model. Monocular vision rigid body posture measurement system is designed; experimentally in each coordinate system determined coordinate a unified method to unify the each feature point measure coordinates; theoretical analysis sources of error from rigid body posture measurement system simulation experiments. Combined with the actual experimental analysis system under the condition of simulation error of pose accuracy of measurement, gives the comprehensive error of measurement system, for improving measurement precision of certain theoretical guiding significance.
Kinematic simulation of human gait with a multi-rigid-body foot model
Institute of Scientific and Technical Information of China (English)
YANG Yan; HU Xiaochun; LI Xiaopeng
2012-01-01
The paper builds a multi-rigid-body model of human with a 4-rigid-body foot in the 3D CAD software Solidworks, based on human anatomy. By controlling the rotation of the ankle and major joints of human body while walking, the Kinematic simulation was performed in the dynamics simulation software ADAMS. The paper analyzes the simulate results and points out deficiencies in the current work and the direction of research efforts in future.
Eigenvalues of an axially loaded cantilever beam with an eccentric end rigid body
Lajimi, S Amir Mousavi
2014-01-01
An analytical form of the characteristic equation for a vertically mounted cantilever beam with an end rigid body is obtained and solved for the eigenvalues of the structure. The effect of the weight of the structure is taken into consideration by estimating the load as a function of the length of the beam. The mass, rotary inertia and eccentricity of the end rigid body are demonstrated to considerably affect the eigenvalues of the structure.
Non-existence of Physical Classical Solutions to Euler's Equations of Rigid Body Dynamics
Wilkinson, Mark
2015-01-01
We prove that one cannot construct, for arbitrary initial data, global-in-time physical classical solutions to Euler's equations of continuum rigid body mechanics when the constituent rigid bodies are not perfect spheres. By 'physical' solutions, we mean those that conserve the total linear momentum, angular momentum and kinetic energy of any given initial datum. The reason for absence of classical solutions is due to the non-existence of velocity scattering maps which resolve a collision bet...
Rigid Body Inertia Estimation Using Extended Kalman and Savitzky-Golay Filters
Donghoon Kim; Sungwook Yang; Sangchul Lee
2016-01-01
Inertia properties of rigid body such as ground, aerial, and space vehicles may be changed by several occasions, and this variation of the properties influences the control accuracy of the rigid body. For this reason, accurate inertia properties need to be obtained for precise control. An estimation process is required for both noisy gyro measurements and the time derivative of the gyro measurements. In this paper, an estimation method is proposed for having reliable estimates of inertia prop...
Bounded attitude control of rigid bodies: Real-time experimentation to a quadrotor mini-helicopter
Guerrero-Castellanos, Fermi; Marchand, Nicolas; Hably, Ahmad; Lesecq, Suzanne; Delamare, Jérôme
2011-01-01
A quaternion-based feedback is developed for the attitude stabilization of rigid bodies. The control design takes into account a priori input bounds and is based on nested saturation approach. It results in a very simple controller suitable for an embedded use with low computational resources available. The proposed method is generic not restricted to symmetric rigid bodies and does not require the knowledge of the inertia matrix of the body. The control law can be tuned to force closed-loop ...
Contact Point Generation for Convex Polytopes in Interactive Rigid Body Dynamics
DEFF Research Database (Denmark)
Silcowitz-Hansen, Morten; Niebe, Sarah Maria; Erleben, Kenny
When computing contact forces in rigid body dynamics systems, most state-of-the-art solutions use iterative methods such as the projected Gauss–Seidel (PGS) method. Methods such as the PGS method are preferred for their robustness. However, the time-critical nature of interactive applications...... for convex polytopes. A novel contact point generation method is presented, which is based on growth distances and Gauss maps. We demonstrate improvements when using our method in the context of interactive rigid body simulation...
Geometric relations between rigid bodies (Part 2): From semantics to software
De Laet T.; Bellens S.; Bruyninckx H.; De Schutter J.
2013-01-01
Rigid bodies are essential primitives in the modelling of robotic devices, tasks, and percep- tion. Basic geometric relations between rigid bodies in- clude relative position, orientation, pose, linear veloc- ity, angular velocity, twist, force, torque, and wrench. In Part 1, we explicitly stated the semantics of all coordinate-invariant properties and operations, and, more importantly, all the choices that are made in co- ordinate representations of these geometric re...
Elastic Plates in Multibody Systems: A Treatment Using Existing Rigid Body Codes
International Nuclear Information System (INIS)
In the present paper, it is shown how one can employ existing rigid body codes to handle systems containing elastic plates by using a Rayleigh-Ritz discretization procedure. The equations of motion are formulated for a rectangular plate undergoing large rigid body motions but small elastic deformations. Geometric nonlinearities in the elastic coordinates are taken into account to include the effect of dynamic stiffening. As an example, a spin-up maneuver for a simply-supported plate is treated
Estimating the orientation of a rigid body moving in space using inertial sensors
Energy Technology Data Exchange (ETDEWEB)
He, Peng, E-mail: peng.he.1@ulaval.ca; Cardou, Philippe, E-mail: pcardou@gmc.ulaval.ca [Université Laval, Robotics Laboratory, Department of Mechanical Engineering (Canada); Desbiens, André, E-mail: andre.desbiens@gel.ulaval.ca [Université Laval, Department of Electrical and Computer Engineering (Canada); Gagnon, Eric, E-mail: Eric.Gagnon@drdc-rddc.gc.ca [RDDC Valcartier (Canada)
2015-09-15
This paper presents a novel method of estimating the orientation of a rigid body moving in space from inertial sensors, by discerning the gravitational and inertial components of the accelerations. In this method, both a rigid-body kinematics model and a stochastic model of the human-hand motion are formulated and combined in a nonlinear state-space system. The state equation represents the rigid body kinematics and stochastic model, and the output equation represents the inertial sensor measurements. It is necessary to mention that, since the output equation is a nonlinear function of the state, the extended Kalman filter (EKF) is applied. The absolute value of the error from the proposed method is shown to be less than 5 deg in simulation and in experiments. It is apparently stable, unlike the time-integration of gyroscope measurements, which is subjected to drift, and remains accurate under large accelerations, unlike the tilt-sensor method.
Estimating the orientation of a rigid body moving in space using inertial sensors
International Nuclear Information System (INIS)
This paper presents a novel method of estimating the orientation of a rigid body moving in space from inertial sensors, by discerning the gravitational and inertial components of the accelerations. In this method, both a rigid-body kinematics model and a stochastic model of the human-hand motion are formulated and combined in a nonlinear state-space system. The state equation represents the rigid body kinematics and stochastic model, and the output equation represents the inertial sensor measurements. It is necessary to mention that, since the output equation is a nonlinear function of the state, the extended Kalman filter (EKF) is applied. The absolute value of the error from the proposed method is shown to be less than 5 deg in simulation and in experiments. It is apparently stable, unlike the time-integration of gyroscope measurements, which is subjected to drift, and remains accurate under large accelerations, unlike the tilt-sensor method
Energy Technology Data Exchange (ETDEWEB)
Ismail, Norilmi Amilia, E-mail: aenorilmi@usm.my [School of Aerospace Engineering, Engineering Campus, Universiti Sains Malaysia, 14300 Nibong Tebal, Pulau Pinang (Malaysia)
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.
New optimal control laws for attitude of a rigid body motion without angular velocity measurements
Energy Technology Data Exchange (ETDEWEB)
El-Gohary, Awad [Department of Statistics and Operational Research, Faculty of Science King Saud University, P.O. Box 2455, Riyadh 11451 (Saudi Arabia)] e-mail: aigohary@ksu.edu.sa
2005-08-01
In this paper we shall use the passive properties of Euler dynamic equations as well as the structural properties of kinematic equations in terms of Cayley-Rodrigues and Modified Rodrigues parameters to derive optimal control laws without any information about the angular velocity of the rigid body. The interesting difference in the current study is the assumption that only the kinematics attitude parameters are available for the control process. The optimal control laws ensure the optimal asymptotic stability of the rigid body motion and minimize a selecting performance are obtained in terms of the kinematics attitude parameters and their estimates. Numerical examples are presented to demonstrate the theoretical results.
Physical pendulum—a simple experiment can give comprehensive information about a rigid body
Kladivová, Mária; Mucha, L'ubomír
2014-03-01
A simple experiment with a physical pendulum examining some aspects of rigid body motion is presented in this paper. The experiment consists of measuring the period of oscillation of a rod with non-homogeneous mass distribution used as a physical pendulum, dependent upon the position of the pivot axis. The obtained dependence provides sufficient information to calculate the position of the centre of mass, moment of inertia of the rigid body and local gravitational acceleration. This experiment is intended for secondary school and undergraduate students.
Reyhanoglu, Mahmut
1996-01-01
There has been much interest over the past decade in the problem of asymptotic stabilization of the angular velocity of a rigid body with only two torque inputs. The smooth feedback laws proposed in the literature provide asymptotic stability with nonexponential convergence rates. This paper propose
Reyhanoglu, Mahmut
1996-01-01
There has been much interest over the past decade in the problem of asymptotic stabilization of the angular velocity of a rigid body with only two torque inputs. The smooth feedback laws proposed in the literature provide asymptotic stability with nonexponential convergence rates. This paper proposes discontinuous feedback laws to achieve asymptotic stability with exponential convergence rates
Patrinopoulos, Matthaios; Kefalis, Chrysovalantis
2015-12-01
In this paper, we focus on smartphones as experimental tools; specifically we use the gyroscope sensor of a smartphone to study the turning motion of a rigid body. Taking into consideration recent work concerning that topic, we try to use the gyroscope sensor in studying the complex motion of a rolling cylinder on a slope.
Lorentz Contraction, Bell's Spaceships and Rigid Body Motion in Special Relativity
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…
Reverse rotations in the circularly-driven motion of a rigid body
Parisio, Fernando
2008-01-01
We study the dynamical response of a circularly-driven rigid body, focusing on the description of intrinsic rotational behavior (reverse rotations). The model system we address is integrable but nontrivial, allowing for qualitative and quantitative analysis. A scale free expression defining the separation between possible spinning regimes is obtained.
On the linear problem arising from motion of a fluid around a moving rigid body
Czech Academy of Sciences Publication Activity Database
Nečasová, Šárka; Wolf, J.
2015-01-01
Roč. 140, č. 2 (2015), s. 241-259. ISSN 0862-7959 R&D Projects: GA ČR(CZ) GAP201/11/1304 Institutional support: RVO:67985840 Keywords : incompressible fluid * rotating rigid body * strong solution Subject RIV: BA - General Mathematics http://hdl.handle.net/10338.dmlcz/144329
DEFF Research Database (Denmark)
Silcowitz, Morten; Niebe, Sarah Maria; Erleben, Kenny
2009-01-01
n interactive physical simulation, contact forces are applied to prevent rigid bodies from penetrating each other. Accurate contact force determination is a computationally hard problem. Thus, in practice one trades accuracy for performance. The result is visual artifacts such as viscous or damped...
Projected Gauss-Seidel Subspace Minimization Method for Interactive Rigid Body Dynamics
DEFF Research Database (Denmark)
Silcowitz, Morten; Niebe, Sarah Maria; Erleben, Kenny
2010-01-01
In interactive physical simulation, contact forces are applied to prevent rigid bodies from penetrating and to control slipping between bodies. Accurate contact force determination is a computationally hard problem. Thus, in practice one trades accuracy for performance. This results in visual...
Reconstructing rotations and rigid body motions from exact point correspondences through reflections
D. Fontijne; L. Dorst
2011-01-01
We describe a new algorithm to reconstruct a rigid body motion from point correspondences. The algorithm works by constructing a series of reflections which align the points with their correspondences one by one. This is naturally and efficiently implemented in the conformal model of geometric algeb
DEFF Research Database (Denmark)
Nielsen, Martin Bjerre; Krenk, Steen
2012-01-01
A conservative time integration algorithm for rigid body rotations is presented in a purely algebraic form in terms of the four quaternions components and the four conjugate momentum variables via Hamilton’s equations. The introduction of an extended mass matrix leads to a symmetric set of eight...
Institute of Scientific and Technical Information of China (English)
Yong Wang; Jian Kang
2015-01-01
In traditional inverse synthetic aperture radar (ISAR) imaging of moving targets with rotational parts, the micro-Doppler (m-D) effects caused by the rotational parts influence the quality of the radar images. Recently, L. Stankovic proposed an m-D removal method based on L-statistics, which has been proved effective and simple. The algorithm can extract the m-D effects according to different behaviors of signals induced by rotational parts and rigid bodies in time-frequency (T-F) domain. However, by removing m-D effects, some useful short time Fourier transform (STFT) samples of rigid bodies are also extracted, which induces the side lobe problem of rigid bodies. A parameter estimation method for rigid bodies after m-D removal is proposed, which can accurately re-cover rigid bodies and avoid the side lobe problem by only using m-D removal. Simulations are given to validate the effectiveness of the proposed method.
Controlling Mixing Inside a Droplet by Time Dependent Rigid-body Rotation
Chabreyrie, R; Chandre, C; Singh, P; Aubry, N
2008-01-01
The use of microscopic discrete fluid volumes (i.e., droplets) as microreactors for digital microfluidic applications often requires mixing enhancement and control within droplets. In this work, we consider a translating spherical liquid droplet to which we impose a time periodic rigid-body rotation which we model using the superposition of a Hill vortex and an unsteady rigid body rotation. This perturbation in the form of a rotation not only creates a three-dimensional chaotic mixing region, which operates through the stretching and folding of material lines, but also offers the possibility of controlling both the size and the location of the mixing. Such a control is achieved by judiciously adjusting the three parameters that characterize the rotation, i.e., the rotation amplitude, frequency and orientation of the rotation. As the size of the mixing region is increased, complete mixing within the drop is obtained.
The tennis racket effect in a three-dimensional rigid body
Van Damme, L; Sugny, D
2016-01-01
We propose a complete theoretical description of the tennis racket effect, which occurs in the free rotation of a three-dimensional rigid body. This effect is characterized by a flip ($\\pi$- rotation) of the head of the racket when a full ($2\\pi$) rotation around the unstable inertia axis is considered. We describe the asymptotics of the phenomenon and conclude about the robustness of this effect with respect to the values of the moments of inertia and the initial conditions of the dynamics. This shows the generality of this geometric property which can be found in a variety of rigid bodies. A simple analytical formula is derived to estimate the twisting effect in the general case. Different examples are discussed.
Compliant mechanism road bicycle brake: a rigid-body replacement case study
Energy Technology Data Exchange (ETDEWEB)
Olsen, Brian M [Los Alamos National Laboratory; Howell, Larry L [NON LANL; Magleby, Spencer P [NON LANL
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.
Conservative rigid body dynamics by convected base vectors with implicit constraints
DEFF Research Database (Denmark)
Krenk, Steen; Nielsen, Martin Bjerre
2014-01-01
of the base vectors. Orthogonality and unit length of the base vectors are imposed by constraining the equivalent Green strain components, and the kinetic energy is represented corresponding to rigid body motion. The equations of motion are obtained via Hamilton’s equations including the zero......A conservative time integration formulation is developed for rigid bodies based on a convected set of orthonormal base vectors. The base vectors are represented in terms of their absolute coordinates, and thus the formulation makes use of three translation components, plus nine components......-strain conditions as well as external constraints via Lagrange multipliers. Subsequently, the Lagrange multipliers associated with the internal zero-strain constraints are eliminated by use of a set of orthogonality conditions between the generalized displacements and the momentum vector, leaving a set...
On the long-time behaviour of a rigid body immersed in a viscous fluid
Czech Academy of Sciences Publication Activity Database
Feireisl, Eduard; Nečasová, Šárka
2011-01-01
Roč. 90, č. 1 (2011), s. 59-66. ISSN 0003-6811 R&D Projects: GA ČR GA201/09/0917; GA AV ČR IAA100190804 Institutional research plan: CEZ:AV0Z10190503 Keywords : rigid body * viscous fluid * Navier-Stokes system Subject RIV: BA - General Mathematics Impact factor: 0.744, year: 2011 http://www.tandfonline.com/doi/abs/10.1080/00036811003735964
Inertial Vector Based Attitude Stabilization of Rigid Body Without Angular Velocity Measurements
Benziane, L.; Benallegue, A.; Chitour, Y.; Tayebi, A.
2015-01-01
We address the problem of attitude stabilization of a rigid body, in which neither the angular velocity nor the instantaneous measurements of the attitude are used in the feedback, only body vector measurements are needed. The design of the controller is based on an angular velocity observer-like system, where a first order linear auxiliary system based directly on vector measurements is introduced. The introduction of gain matrices provides more tuning flexibility and better results compared...
Fitzpatrick, P. M.; Harmon, G. R.; Cochran, J. E.; Shaw, W. A.
1974-01-01
Some methods of approaching a solution to the Hamilton-Jacobi equation are outlined and examples are given to illustrate particular methods. These methods may be used for cases where the Hamilton-Jacobi equation is not separable and have been particularly useful in solving the rigid body motion of an earth satellite subjected to gravity torques. These general applications may also have usefulness in studying the motion of satellites with aerodynamic torque and in studying space vehicle motion where thrusting is involved.
Geometric Tracking Control of the Attitude Dynamics of a Rigid Body on SO(3)
Lee, Taeyoung
2010-01-01
This paper provides new results for a tracking control of the attitude dynamics of a rigid body. Both of the attitude dynamics and the proposed control system are globally expressed on the special orthogonal group, to avoid complexities and ambiguities associated with other attitude representations such as Euler angles or quaternions. By selecting an attitude error function carefully, we show that the proposed control system guarantees a desirable tracking performance uniformly for nontrivial...
Stability Analysis of a Rigid Body with a Flexible Attachment Using the Energy-Casimir Method
Posbergh, T. A.; Krishnaprasad, Perinkulam S.; Marsden, Jerrold E.
1987-01-01
We consider a system consisting of a rigid body to which a linear extensible shear beam is attached. For such a system the Energy-Casimir method can be used to investigate the stability of the equilibria. In the case we consider, it can be shown that a test for (formal) stability reduces to checking the positive definiteness of two matrices which depend on the parameters of the system and the particular equilibrium about which the stability is to be ascertained.
The phase topology of a special case of Goryachev integrability in rigid body dynamics
Energy Technology Data Exchange (ETDEWEB)
Ryabov, P. E., E-mail: orelryabov@mail.ru [Financial University under the Government of the Russian Federation, Moscow (Russian Federation)
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)
Eigenvalue analysis of a cantilever beam-rigid-body MEMS gyroscope
Lajimi, Seyed Amir Mousavi; Abdel-Rahman, Eihab
2014-01-01
The eigenvalues of a new microbeam-rigid-body gyroscope are computed and studied to show the variation of frequencies versus the input spin rate. To this end, assuming the harmonic solution of the dynamic equation of motion the characteristic equation is obtained and solved for the natural frequencies of the system in the rotating frame. It is shown that the difference between the natural frequencies (eigenvalues) proportionally grows with the input angular displacement rate.
A stable FSI algorithm for light rigid bodies in compressible flow
Banks, J. W.; Henshaw, W. D.; Sjögreen, B.
2013-07-01
In this article we describe a stable partitioned algorithm that overcomes the added mass instability arising in fluid-structure interactions of light rigid bodies and inviscid compressible flow. The new algorithm is stable even for bodies with zero mass and zero moments of inertia. The approach is based on a local characteristic projection of the force on the rigid body and is a natural extension of the recently developed algorithm for coupling compressible flow and deformable bodies [1-3]. The new algorithm advances the solution in the fluid domain with a standard upwind scheme and explicit time-stepping. The Newton-Euler system of ordinary differential equations governing the motion of the rigid body is augmented by added mass correction terms. This system, which is very stiff for light bodies, is solved with an A-stable diagonally implicit Runge-Kutta scheme. The implicit system (there is one independent system for each body) consists of only 3d+d2 scalar unknowns in d=2 or d=3 space dimensions and is fast to solve. The overall cost of the scheme is thus dominated by the cost of the explicit fluid solver. Normal mode analysis is used to prove the stability of the approximation for a one-dimensional model problem and numerical computations confirm these results. In multiple space dimensions the approach naturally reveals the form of the added mass tensors in the equations governing the motion of the rigid body. These tensors, which depend on certain surface integrals of the fluid impedance, couple the translational and angular velocities of the body. Numerical results in two space dimensions, based on the use of moving overlapping grids and adaptive mesh refinement, demonstrate the behavior and efficacy of the new scheme. These results include the simulation of the difficult problems of shock impingement on an ellipse and a more complex body with appendages, both with zero mass.
Rigid Body Time Integration by Convected Base Vectors with Implicit Constraints
Krenk, Steen; Nielsen, Martin Bjerre
2013-01-01
A conservative time integration algorithm based on a convected set of orthonormal base vectors is presented. The equations of motion are derived from an extended Hamiltonian formulation, combining the components of the three base vectors with a set of orthonormality constraints. The particular form of the kinetic energy used in the present formulation is deliberately chosen to correspond to a rigid body rotation, and the orthonormality constraints are introduced via the equivalent Green strai...
Efficient time-symmetric simulation of torqued rigid bodies using Jacobi elliptic functions
Celledoni, E.; Säfström, N.
2006-05-01
If the three moments of inertia are distinct, the solution to the Euler equations for the free rigid body is given in terms of Jacobi elliptic functions. Using the arithmetic-geometric mean algorithm (Abramowitz and Stegun 1992 Handbook of Mathematical Functions with Formulas, Graphs, and Mathematical Tables (New York: Dover)), these functions can be calculated efficiently and accurately. Compared to standard numerical ODE and Lie-Poisson solvers, the overall approach yields a faster and more accurate numerical solution to the Euler equations. This approach is designed for mass asymmetric rigid bodies. In the case of symmetric bodies, the exact solution is available in terms of trigonometric functions, see Dullweber et al (1997 J. Chem. Phys. 107 5840-51), Reich (1996 Fields Inst. Commun. 10 181-91) and Benettin et al (2001 SIAM J. Sci. Comp. 23 1189-203) for details. In this paper, we consider the case of asymmetric rigid bodies subject to external forces. We consider a strategy similar to the symplectic splitting method proposed in Reich (1996 Fields Inst. Commun. 10 181-91) and Dullweber et al (1997 J. Chem. Phys. 107 5840-51). The method proposed here is time-symmetric. We decompose the vector field of our problem into a free rigid body (FRB) problem and another completely integrable vector field. The FRB problem consists of the Euler equations and a differential equation for the 3 × 3 orientation matrix. The Euler equations are integrated exactly while the matrix equation is approximated using a truncated Magnus series. In our experiments, we observe that the overall numerical solution benefits greatly from the very accurate solution of the Euler equations. We apply the method to the heavy top and the simulation of artificial satellite attitude dynamics.
Efficient time-symmetric simulation of torqued rigid bodies using Jacobi elliptic functions
International Nuclear Information System (INIS)
If the three moments of inertia are distinct, the solution to the Euler equations for the free rigid body is given in terms of Jacobi elliptic functions. Using the arithmetic-geometric mean algorithm (Abramowitz and Stegun 1992 Handbook of Mathematical Functions with Formulas, Graphs, and Mathematical Tables (New York: Dover)), these functions can be calculated efficiently and accurately. Compared to standard numerical ODE and Lie-Poisson solvers, the overall approach yields a faster and more accurate numerical solution to the Euler equations. This approach is designed for mass asymmetric rigid bodies. In the case of symmetric bodies, the exact solution is available in terms of trigonometric functions, see Dullweber et al (1997 J. Chem. Phys. 107 5840-51), Reich (1996 Fields Inst. Commun. 10 181-91) and Benettin et al (2001 SIAM J. Sci. Comp. 23 1189-203) for details. In this paper, we consider the case of asymmetric rigid bodies subject to external forces. We consider a strategy similar to the symplectic splitting method proposed in Reich (1996 Fields Inst. Commun. 10 181-91) and Dullweber et al (1997 J. Chem. Phys. 107 5840-51). The method proposed here is time-symmetric. We decompose the vector field of our problem into a free rigid body (FRB) problem and another completely integrable vector field. The FRB problem consists of the Euler equations and a differential equation for the 3 x 3 orientation matrix. The Euler equations are integrated exactly while the matrix equation is approximated using a truncated Magnus series. In our experiments, we observe that the overall numerical solution benefits greatly from the very accurate solution of the Euler equations. We apply the method to the heavy top and the simulation of artificial satellite attitude dynamics
In silico single-molecule manipulation of DNA with rigid body dynamics.
Pascal Carrivain; Maria Barbi; Jean-Marc Victor
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 ex...
Molina, John Jairo; Yamamoto, Ryoichi
2013-01-01
An improved formulation of the Smoothed Profile method is introduced to perform direct numerical simulations of arbitrary rigid body dispersions in a Newtonian host solvent. Previous implementations of the method were restricted to spherical particles, severely limiting the types of systems that could be studied. The validity of the method is carefully examined by computing the friction/mobility tensors for a wide variety of geometries and comparing them to reference values obtained from accu...
Molina, John J; Yamamoto, Ryoichi
2013-12-21
An improved formulation of the "Smoothed Profile" method is introduced to perform direct numerical simulations of arbitrary rigid body dispersions in a Newtonian host solvent. Previous implementations of the method were restricted to spherical particles, severely limiting the types of systems that could be studied. The validity of the method is carefully examined by computing the friction/mobility tensors for a wide variety of geometries and comparing them to reference values obtained from accurate solutions to the Stokes-Equation. PMID:24359350
Modeling the bacterial flagellum by an elastic network of rigid bodies
Speier, C.; Vogel, R.; Stark, H.
2011-08-01
Bacteria such as Escherichia coli propel themselves by rotating a bundle of helical filaments, each driven by a rotary motor embedded in the cell membrane. Each filament is an assembly of thousands of copies of the protein flagellin which assumes two different states. We model the filament by an elastic network of rigid bodies that form bonds with one another according to a scheme suggested by Namba and Vondervistz (1997 Q. Rev. Biophys. 30 1-65) and add additional binding sites at the inner part of the rigid body. Our model reproduces the helical parameters of the 12 possible polymorphic configurations very well. We demonstrate that its energetical ground state corresponds to the normal helical form, usually observed in nature, only when inner and outer binding sites of the rigid body have a large axial displacement. This finding correlates directly to the elongated shape of the flagellin molecule. An Ising Hamiltonian in our model directly addresses the two states of the flagellin protein. It contains an external field that represents external parameters which allow us to alter the ground state of the filament.
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.
Rigid Body Modes Influence On Microvibration Analysis-Application To Swarm
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
The tennis racket effect in a three-dimensional rigid body
L van Damme; Mardesic, P.; Sugny, D.
2016-01-01
We propose a complete theoretical description of the tennis racket effect, which occurs in the free rotation of a three-dimensional rigid body. This effect is characterized by a flip ($\\pi$- rotation) of the head of the racket when a full ($2\\pi$) rotation around the unstable inertia axis is considered. We describe the asymptotics of the phenomenon and conclude about the robustness of this effect with respect to the values of the moments of inertia and the initial conditions of the dynamics. ...
On Classical Dynamics of Affinely-Rigid Bodies Subject to the Kirchhoff-Love Constraints
Directory of Open Access Journals (Sweden)
Vasyl Kovalchuk
2010-04-01
Full Text Available In this article we consider the affinely-rigid body moving in the three-dimensional physical space and subject to the Kirchhoff-Love constraints, i.e., while it deforms homogeneously in the two-dimensional central plane of the body it simultaneously performs one-dimensional oscillations orthogonal to this central plane. For the polar decomposition we obtain the stationary ellipsoids as special solutions of the general, strongly nonlinear equations of motion. It is also shown that these solutions are conceptually different from those obtained earlier for the two-polar (singular value decomposition.
Euler-Poincaré Reduction of Externally Forced Rigid Body Motion
DEFF Research Database (Denmark)
Wisniewski, Rafal; Kulczycki, P.
2004-01-01
If a mechanical system experiences symmetry, the Lagrangian becomes invariant under a certain group action. This property leads to substantial simplification of the description of movement. The standpoint in this article is a mechanical system affected by an external force of a control action...... control system generates an external force, which may break the symmetry in the dynamics. This paper shows how to model and to control a mechanical system on the reduced phase space, such that complete state space asymptotic stabilization can be achieved. The paper comprises a specialization of the well......-known Euler-Poincaré reduction to a rigid body motion with forcing....
Inertial Motions of a Rigid Body with a cavity filled with a viscous liquid
Galdi, Giovanni P.; Mazzone, Giusy; Zunino, Paolo
2014-01-01
We study inertial motions of the coupled system, S, constituted by a rigid body containing a cavity that is completely filled with a viscous liquid. We show that for data of arbitrary size (initial kinetic energy and total angular momentum) every weak solution (a la Leray-Hopf) converges, as time goes to infinity, to a uniform rotation, thus proving a famous "conjecture" of Zhukovskii. Moreover we show that, in a wide range of initial data, this rotation must occur along the central axis of i...
Rigid Body Time Integration by Convected Base Vectors with Implicit Constraints
DEFF Research Database (Denmark)
Krenk, Steen; Nielsen, Martin Bjerre
2013-01-01
of the kinetic energy used in the present formulation is deliberately chosen to correspond to a rigid body rotation, and the orthonormality constraints are introduced via the equivalent Green strain components of the base vectors. The particular form of the extended inertia tensor used here implies a......A conservative time integration algorithm based on a convected set of orthonormal base vectors is presented. The equations of motion are derived from an extended Hamiltonian formulation, combining the components of the three base vectors with a set of orthonormality constraints. The particular form...
Asymptotic behaviour of a rigid body with a cavity filled by a viscous liquid
Disser, Karoline
2014-01-01
We consider the system of equations modeling the free motion of a rigid body with a cavity filled by a viscous (Navier-Stokes) liquid. We give a rigorous proof of Zhukovskiy's Theorem, which states that in the limit of time going to infinity, the relative fluid velocity tends to zero and the rigid velocity of the full structure tends to a steady rotation around one of the principle axes of inertia. The existence of global weak solutions for this system was established previously. In particula...
On the identifiability of a rigid body moving in a stationary viscous fluid
International Nuclear Information System (INIS)
This paper is devoted to a geometrical inverse problem associated with a fluid–structure system. More precisely, we consider the interaction between a moving rigid body and a viscous and incompressible fluid. Assuming a low Reynolds regime, the inertial forces can be neglected and, therefore, the fluid motion is modelled by the Stokes system. We first prove the well posedness of the corresponding system. Then we show an identifiability result: with one measure of the Cauchy forces of the fluid on one given part of the boundary and at some positive time, the shape of a convex body and its initial position are identified. (paper)
Comparison of Point and Line Features and Their Combination for Rigid Body Motion Estimation
DEFF Research Database (Denmark)
Pilz, Florian; Pugeault, Nicolas; Krüger, Norbert
2009-01-01
This paper discusses the usage of dierent image features and their combination in the context of estimating the motion of rigid bodies (RBM estimation). From stereo image sequences, we extract line features at local edges (coded in so called multi-modal primitives) as well as point features (by...... means of SIFT descriptors). All features are then matched across stereo and time, and we use these correspondences to estimate the RBM by solving the 3D-2D pose estimation problem. We test dierent feature sets on various stereo image sequences, recorded in realistic outdoor and indoor scenes. We...
Conservative integration of rigid body motion by quaternion parameters with implicit constraints
DEFF Research Database (Denmark)
Nielsen, Martin Bjerre; Krenk, Steen
2012-01-01
An angular momentum and energy‐conserving time integration algorithm for rigid body rotation is formulated in terms of the quaternion parameters and the corresponding four‐component conjugate momentum vector via Hamilton's equations. The introduction of an extended mass matrix leads to a symmetric...... equations via the set of momentum equations. Initially, the normalization of the quaternion array is introduced via a Lagrange multiplier. However, this Lagrange multiplier can be expressed explicitly in terms of the gradient of the external load potential, and elimination of the Lagrange multiplier from...
Analytic Theory and Control of the Motion of Spinning Rigid Bodies
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
Modeling and experimentation with asymmetric rigid bodies: a variation on disks and inclines
International Nuclear Information System (INIS)
We study the ascending motion of a disk rolling on an incline when its centre of mass lies outside the disk axis. The problem is suitable as laboratory project for a first course in mechanics at the undergraduate level and goes beyond typical textbook problems about bi-dimensional rigid body motions. We develop a theoretical model for the disk motion based on mechanical energy conservation and compare its predictions with experimental data obtained by digital video recording. Using readily available resources, a very satisfactory agreement is obtained between the model and the experimental observations. These results complement previous ones that have been reported in the literature for similar systems. (paper)
International Nuclear Information System (INIS)
Modeling of multibody dynamics with flexible links is a challenging task, which not only involves the effect of rigid body motion on elastic deformations, but also includes the influence of elastic deformations on rigid body motion. This paper presents coupling characteristics of rigid body motions and elastic motions of a 3-PRR parallel manipulator with three flexible intermediate links. The intermediate links are modeled as Euler-Bernoulli beams with pinned-pinned boundary conditions based on the assumed mode method (AMM). Using Lagrange multipliers, the fully coupled equations of motions of the flexible parallel manipulator are developed by incorporating the rigid body motions with elastic motions. The mutual dependence of elastic deformations and rigid body motions are investigated from the analysis of the derived equations of motion. Open-loop simulation without joint motion controls and closed-loop simulation with joint motion controls are performed to illustrate the effect of elastic motion on rigid body motions and the coupling effect amongst flexible links. These analyses and results provide valuable insight to the design and control of the parallel manipulator with flexible intermediate links
Energy Technology Data Exchange (ETDEWEB)
Zhang Xuping, E-mail: zhxp@mie.utoronto.ca; Mills, James K., E-mail: mills@mie.utoronto.ca; Cleghorn, William L. [University of Toronto, Department of Mechanical and Industrial Engineering (Canada)], E-mail: cleghrn@mie.utoronto.ca
2009-03-15
Modeling of multibody dynamics with flexible links is a challenging task, which not only involves the effect of rigid body motion on elastic deformations, but also includes the influence of elastic deformations on rigid body motion. This paper presents coupling characteristics of rigid body motions and elastic motions of a 3-PRR parallel manipulator with three flexible intermediate links. The intermediate links are modeled as Euler-Bernoulli beams with pinned-pinned boundary conditions based on the assumed mode method (AMM). Using Lagrange multipliers, the fully coupled equations of motions of the flexible parallel manipulator are developed by incorporating the rigid body motions with elastic motions. The mutual dependence of elastic deformations and rigid body motions are investigated from the analysis of the derived equations of motion. Open-loop simulation without joint motion controls and closed-loop simulation with joint motion controls are performed to illustrate the effect of elastic motion on rigid body motions and the coupling effect amongst flexible links. These analyses and results provide valuable insight to the design and control of the parallel manipulator with flexible intermediate links.
Rotational kinematics of a rigid body about a fixed axis: development and analysis of an inventory
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.
Closed-Loop Control of Satellite Formations Using a Quasi-Rigid Body Formulation
Blake, Christopher; Misra, Arun K.
2011-04-01
Satellites in formation work together to fulfill the role of a larger satellite. The purpose of this article is to develop a quasi-rigid body formulation for modeling and controlling such a formation as a single entity. In this article, a definition of a quasi-rigid body coordinate frame is presented, which, when attached to a formation, conveniently describes its orientation in space. Using this formulation, the equations of motion for a satellite formation are recast, and natural circular formations are expressed more succinctly. When the J 2 perturbation is considered, a correction factor on the formation's spin rate is introduced. The control of a satellite formation can effectively be separated into (1) a control torque to maintain the attitude and (2) control forces that maintain the rigidity of the formation. With this in mind, a nonlinear Lyapunov controller is derived using the formulation, which acts on the formation as a whole. Simulations validate this controller and illustrate its utility for maintaining circular formations, in particular, in the presence of gravitational perturbations.
Rigid Body Inertia Estimation Using Extended Kalman and Savitzky-Golay Filters
Directory of Open Access Journals (Sweden)
Donghoon Kim
2016-01-01
Full Text Available Inertia properties of rigid body such as ground, aerial, and space vehicles may be changed by several occasions, and this variation of the properties influences the control accuracy of the rigid body. For this reason, accurate inertia properties need to be obtained for precise control. An estimation process is required for both noisy gyro measurements and the time derivative of the gyro measurements. In this paper, an estimation method is proposed for having reliable estimates of inertia properties. First, the Euler equations of motion are reformulated to obtain a regressor matrix. Next, the extended Kalman filter is adopted to reduce the noise effects in gyro angular velocity measurements. Last, the inertia properties are estimated using linear least squares. To achieve reliable and accurate angular accelerations, a Savitzky-Golay filter based on an even number sampled data is utilized. Numerical examples are presented to demonstrate the performance of the proposed algorithm for the case of a space vehicle. The numerical simulation results show that the proposed algorithm provides accurate inertia property estimates in the presence of noisy measurements.
The general problem of the motion of coupled rigid bodies about a fixed point
Leimanis, Eugene
1965-01-01
In the theory of motion of several coupled rigid bodies about a fixed point one can distinguish three basic ramifications. 1. The first, the so-called classical direction of investigations, is concerned with particular cases of integrability ot the equations of motion of a single rigid body about a fixed point,1 and with their geo metrical interpretation. This path of thought was predominant until the beginning of the 20th century and its most illustrious represen tatives are L. EULER (1707-1783), J L. LAGRANGE (1736-1813), L. POINSOT (1777-1859), S. V. KOVALEVSKAYA (1850-1891), and others. Chapter I of the present monograph intends to reflect this branch of investigations. For collateral reading on the general questions dealt with in this chapter the reader is referred to the following textbooks and reports: A. DOMOGAROV [1J, F. KLEIN and A. SOMMERFELD [11, 1 , 1 J, A. G. 2 3 GREENHILL [10J, A. GRAY [1J, R. GRAMMEL [4 J, E. J. ROUTH [21' 2 , 1 2 31' 32J, J. B. SCARBOROUGH [1J, and V. V. GOLUBEV [1, 2J.
Energy Technology Data Exchange (ETDEWEB)
Gerstmayr, J.; Holl, H.J.; Irschik, H. [Inst. of Mechanics and Machine Design, Johannes Kepler University of Linz (Austria)
2001-03-01
A numerical algorithm for studying the development of plastic and damaged zones in a vibrating structural element with a large, guided rigid-body motion is presented. Beam-type elements vibrating in the small-strain regime are considered. A machine element performing rotatory motions, similar to an element of a slider-crank mechanism, is treated as a benchmark problem. Microstructural changes in the deforming material are described by the mesolevel variables of plastic strain and damage, which are consistently included into a macroscopic analysis of the overall beam motion. The method is based on an eigenstrain formulation, considering plastic strain and damage to contribute to an eigenstrain loading of a linear elastic background structure. Rigid-body coordinates are incorporated into this beam-type structural formulation, and an implicit numerical scheme is presented for iterative computation of the eigenstrains from the mesolevel constitutive behavior. Owing to the eigenstrain formulation, any of the existing constitutive models with internal variables could in principle be implemented. Linear elastic/perfectly plastic behavior is exemplarily treated in a numerical study, where plastic strain is connected to the Kachanov damage parameter by a simple damage law. Inelastic effects like plastic shakedown and damage-induced low-cycle rupture are shown to occur in the examplary problems. (orig.)
The Serret-Andoyer Formalism in Rigid-Body Dynamics: I. Symmetries and Perturbations
Gurfil, P; Tangren, W; Efroimsky, M; Gurfil, Pini; Elipe, Antonio; Tangren, William; Efroimsky, Michael
2006-01-01
This paper reviews the Serret-Andoyer (SA) canonical formalism in rigid-body dynamics and presents some new results. As well known, the problem of unsupported and unperturbed rigid rotator can be reduced. The availability of this reduction is offered by the underlying symmetry, which stems from conservation of the angular momentum and rotational kinetic energy. When a perturbation is turned on, these quantities are no longer preserved. Nonetheless, the language of reduced description remains extremely instrumental even in the perturbed case. We describe the canonical reduction performed by the Serret-Andoyer (SA) method, and discuss its applications to attitude dynamics and to the theory of planetary rotation. Specifically, we consider the case of angular-velocity-dependent torques, and discuss the variation-of-parameters inherent antinomy between canonicity and osculation. Finally, we address the transformation of the Andoyer variables into the action-angle ones, using the method of Sadov.
A simplified impact stress analysis of dynamic systems which consist of elastic and rigid bodies
International Nuclear Information System (INIS)
A simplified simulation technique is described for the impact stress analysis of elastic bodies which contain rigid bodies, as in the case of stacked nuclear waste storage canisters. A numerical method based on Guyan's static condensation is proposed which neglects coupling mass terms between rigid and elastic bodies. Modal analytical theory shows that the accuracy of this new method depends on the minimum modal mass ratio (MMMR) between elastic bodies and an induced equivalent mass-spring system, that is, a simplified system which assumes a linear displacement field. For systems with MMMR values greater than 5, this new technique yields results close to those of the more complicated Finite Element Method which requires a considerable computation time. It is a simple and inexpensive way to analyze complex elastic systems which include many rigid parts. (author)
Higher order coupling between rigid-body and elastic motion in flexible mechanisms
International Nuclear Information System (INIS)
The paper presents an investigation of the influence of the higher order coupling terms between the rigid-body and elastic motion into flexible mechanism dynamics. The configuration of the mechanical system is obtained by using the so called hybrid coordinates. The kinematic description of the mechanism was obtained using the D-H 4 x 4 transformation matrices. The elastic deformation of each point of the mechanism is described by the finite element modeling (FEM) type interpolation scheme. The dynamic model of the flexible mechanism consists due to the hybrid coordinates of two groups of differential equations. The first group describes the manipulator transport motion and the second group describes the vibration. In this paper the authors evaluated the contribution of the coupling terms between the two groups of differential equations and selected only those with high contribution
The problem of exact interior solutions for rotating rigid bodies in general relativity
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.
Classical models of affinely-rigid bodies with "thickness" in degenerate dimension
Kovalchuk, Vasyl
2009-01-01
The special interest is devoted to such situations when the material space of our object with affine degrees of freedom has generally lower dimension than the one of the physical space. In other words when we have the $m$-dimensional affinely-rigid body moving in the $n$-dimensional physical space, $m
The Dynamics of a Rigid Body in Potential Flow with Circulation
Vankerschaver, Joris; Marsden, Jerrold E
2010-01-01
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.
The numerical method for three-dimensional impact with friction of multi-rigid-body system
Institute of Scientific and Technical Information of China (English)
无
2006-01-01
The differential equations for planar impacts reduce to an algebraic form, and can be easily solved. For three dimensional impacts with friction, there is no closed-form solution, and numerical integration is required due to the swerve behavior of tangential impulse during collisions. The dynamic governing equations in the impact process are built up in impulse space based on the Lagrangian equation in this paper. The coefficient of restitution defined by Poisson is used as the condition of impact termination. A valid numerical method for solving three-dimensional frictional impact of multi-rigid body system is established. The singular cases of tangential movement in sticking point are especially noticed and analyzed. Several examples are present to reveal the different kinds of tangential movement modes varied with the normal impulse during collision.
Asymptotic of 'rigid-body' motions for nonlinear dynamics: physical insight and methodologies
Pilipchuk, V N
2014-01-01
The purpose of the present work is to show that an adequate basis for understanding the essentially nonlinear phenomena must also be essentially nonlinear however still simple enough to play the role of a basis. It is shown that such types of 'elementary' nonlinear models can be revealed by tracking the hidden links between analytical tools of analyses and subgroups of the rigid-body motions or, in other terms, rigid Euclidean transformation. While the subgroup of rotations is linked with linear and weakly nonlinear vibrations, the translations with reflections can be viewed as a geometrical core of the strongly nonlinear dynamics associated with the so-called vibro-impact behaviors. It is shown that the corresponding analytical approach develops through non-smooth temporal substitutions generated by the impact models.
Coupling Linear Sloshing with Six Degrees of Freedom Rigid Body Dynamics
Dubois, François
2014-01-01
Fluid motion in tanks is usually described in space industry with the so-called Lomen hypothesis which assumes the vorticity is null in the moving frame. We establish in this contribution that this hypothesis is valid only for uniform rotational motions. We give a more general formulation of this coupling problem, with a compact formulation. We consider the mechanical modelling of a rigid body with a motion of small amplitude, containing an incompressible fluid in the linearized regime. We first establish that the fluid motion remains irrotational in a Galilean referential if it is true at the initial time. When continuity of normal velocity and pressure are prescribed on the free surface, we establish that the global coupled problem conserve an energy functional composed by three terms. We introduce the Stokes - Zhukovsky vector fields, solving Neumann problems for the Laplace operator in the fluid in order to represent the rotational rigid motion with irrotational vector fields. Then we have a good framewor...
DEFF Research Database (Denmark)
Sönmez, Ümit; Tutum, Cem Celal
2008-01-01
In this work, a new compliant bistable mechanism design is introduced. The combined use of pseudo-rigid-body model (PRBM) and the Elastica buckling theory is presented for the first time to analyze the new design. This mechanism consists of the large deflecting straight beams, buckling beams, and a...... slider. The kinematic analysis of this new mechanism is studied, using nonlinear Elastica buckling beam theory, the PRBM of a large deflecting cantilever beam, the vector loop closure equations, and numerically solving nonlinear algebraic equations. A design method of the bistable mechanism in...... microdimensions is investigated by changing the relative stiffness of the flexible beams. The actuation force versus displacement characteristics of several cases is explored and the full simulation results of one of the cases are presented. This paper demonstrates the united application of the PRBM and the...
In silico single-molecule manipulation of DNA with rigid body dynamics.
Directory of Open Access Journals (Sweden)
Pascal Carrivain
2014-02-01
Full Text Available 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.
In silico single-molecule manipulation of DNA with rigid body dynamics.
Carrivain, Pascal; Barbi, Maria; Victor, Jean-Marc
2014-02-01
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
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.
DYNAMIC BUCKLING OF ELASTIC-PLASTIC COLUMN IMPACTED BY RIGID BODY
Institute of Scientific and Technical Information of China (English)
无
2006-01-01
The dynamic buckling of an elastic-plastic column subjected to an axial impact by a rigid body was discussed by using the energy law. The traveling process of elastic-plastic waves under impact action was analyzed by characteristics method. The equation of lateral disturbance used to analyze the problem was developed by taking into account the effect of elastic-plastic stress wave. The power series solution of this problem has been the power series approach. The buckling criterion of this problem was proposed by analyzing the characteristics of the solution. The relationship among critical velocity and impact mass, critical buckling length, hardening modulus was given by using theoretical analysis and numerical computation.
A Computational Model for Suspended Large Rigid Bodies in 3D Unsteady Viscous Flows
Xiao, Feng
1999-11-01
A 3D numerical model for computing large rigid objects suspended in fluid flow has been developed. Rather than calculating the surface pressure upon the solid body, we evaluate the net force and torque based on a volume force formulation. The total effective force is obtained by summing up the forces at the Eulerian grids occupied by the rigid body. The effects of the moving bodies are coupled to the fluid flow by imposing the velocity field of the bodies to the fluid. A Poisson equation is used to compute the pressure over the whole domain. The objects are identified by color functions and calculated by the PPM scheme and a tangent function transformation which scales the transition region of the computed interface to a compact thickness. The model is then implemented on a parallel computer of distributed memory and validated with Stokes and low Reynolds number flows.
On potential energies and constraints in the dynamics of rigid bodies and particles
Directory of Open Access Journals (Sweden)
O'reilly Oliver M.
2002-01-01
Full Text Available A new treatment of kinematical constraints and potential energies arising in the dynamics of systems of rigid bodies and particles is presented which is suited to Newtonian and Lagrangian formulations. Its novel feature is the imposing of invariance requirements on the constraint functions and potential energy functions. These requirements are extensively used in continuum mechanics and, in the present context, one finds certain generalizations of Newton's third law of motion and an elucidation of the nature of constraint forces and moments. One motivation for such a treatment can be found by considering approaches where invariance requirements are ignored. In contrast to the treatment presented in this paper, it is shown that this may lead to a difficulty in formulating the equations governing the motion of the system.
On docking, scoring and assessing protein-DNA complexes in a rigid-body framework.
Directory of Open Access Journals (Sweden)
Marc Parisien
Full Text Available We consider the identification of interacting protein-nucleic acid partners using the rigid body docking method FTdock, which is systematic and exhaustive in the exploration of docking conformations. The accuracy of rigid body docking methods is tested using known protein-DNA complexes for which the docked and undocked structures are both available. Additional tests with large decoy sets probe the efficacy of two published statistically derived scoring functions that contain a huge number of parameters. In contrast, we demonstrate that state-of-the-art machine learning techniques can enormously reduce the number of parameters required, thereby identifying the relevant docking features using a miniscule fraction of the number of parameters in the prior works. The present machine learning study considers a 300 dimensional vector (dependent on only 15 parameters, termed the Chemical Context Profile (CCP, where each dimension reflects a specific type of protein amino acid-nucleic acid base interaction. The CCP is designed to capture the chemical complementarities of the interface and is well suited for machine learning techniques. Our objective function is the Chemical Context Discrepancy (CCD, which is defined as the angle between the native system's CCP vector and the decoy's vector and which serves as a substitute for the more commonly used root mean squared deviation (RMSD. We demonstrate that the CCP provides a useful scoring function when certain dimensions are properly weighted. Finally, we explore how the amino acids on a protein's surface can help guide DNA binding, first through long-range interactions, followed by direct contacts, according to specific preferences for either the major or minor grooves of the DNA.
Slaughter, Chris; Yang, Allen Y.; Bagwell, Justin; Checkles, Costa; Sentis, Luis; Vishwanath, Sriram
2011-01-01
Motivated by an emerging theory of robust low-rank matrix representation, in this paper, we introduce a novel solution for online rigid-body motion registration. The goal is to develop algorithmic techniques that enable a robust, real-time motion registration solution suitable for low-cost, portable 3-D camera devices. Assuming 3-D image features are tracked via a standard tracker, the algorithm first utilizes Robust PCA to initialize a low-rank shape representation of the rigid body. Robust ...
C. Aguilar-Ibáñez; M.S. Suárez-Castañón; F. Guzmán-Aguilar
2008-01-01
We present a Hamiltonian control approach for the stabilization of a rigid body system that is controlled by two torques. The stabilization strategy consists in solving a feasible matching condition in order to derive a feedback controller which forces the closed-loop system to be globally asymptotically stable.
Lajimi, Seyed Amir Mousavi
2014-01-01
The nonlinear dynamics of a microbeam-rigid body gyroscope are investigated by using a continuation method. To study the nonlinear dynamics of the system, the Lagrangian of the system is discretized and the reduced-order model is obtained. By using the continuation method, the frequency-response curves are computed and the stability of response is determined.
A navigator-based rigid body motion correction for magnetic resonance imaging
Energy Technology Data Exchange (ETDEWEB)
Ullisch, Marcus Goerge
2012-01-24
A novel three-dimensional navigator k-space trajectory for rigid body motion detection for Magnetic Resonance Imaging (MRI) - the Lissajous navigator - was developed and quantitatively compared to the existing spherical navigator trajectory [1]. The spherical navigator cannot sample the complete spherical surface due to slew rate limitations of the scanner hardware. By utilizing a two dimensional Lissajous figure which is projected onto the spherical surface, the Lissajous navigator overcomes this limitation. The complete sampling of the sphere consequently leads to rotation estimates with higher and more isotropic accuracy. Simulations and phantom measurements were performed for both navigators. Both simulations and measurements show a significantly higher overall accuracy of the Lissajous navigator and a higher isotropy of the rotation estimates. Measured under identical conditions with identical postprocessing, the measured mean absolute error of the rotation estimates for the Lissajous navigator was 38% lower (0.3 ) than for the spherical navigator (0.5 ). The maximum error of the Lissajous navigator was reduced by 48% relative to the spherical navigator. The Lissajous navigator delivers higher accuracy of rotation estimation and a higher degree of isotropy than the spherical navigator with no evident drawbacks; these are two decisive advantages, especially for high-resolution anatomical imaging.
Application of rigid-body-spring-model to modeling of ultimate behavior of piping systems
International Nuclear Information System (INIS)
When piping systems of nuclear power plants are subjected to large deformation during earthquakes, plasticity tends to concentrate at local elements such as elbows, tees and supports. In analyzing responses of such structures, it is effective to clearly divide them into those plastic parts and other linear parts. The rigid-body-spring-model (RBSM) is a structural analysis method which is effective in representing such discretely nonlinear systems. In order to apply RBSM for this purpose, load-displacement relations of the local plastic parts have to be determined, and it can be established by structural experiments of those independent elements. In this study, the authors conducted cyclic in-plane bending experiments of thin-walled elbows, and determined their asymmetric load-displacement relations by using the Ramberg-Osgood model and empirical hysteresis curves. Then, they are incorporated into nonlinear spring model of RBSM, which could accurately simulate the complex hysteresis loops observed in the experiments. Finally, the authors proposed a framework of limit-state seismic evaluation procedure for nuclear piping systems which uses RBSM and experimentally-determined load-displacement relations of pipe elements. Refs. 2 (author)
Inertial Motions of a Rigid Body with a Cavity Filled with a Viscous Liquid
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.
A navigator-based rigid body motion correction for magnetic resonance imaging
International Nuclear Information System (INIS)
A novel three-dimensional navigator k-space trajectory for rigid body motion detection for Magnetic Resonance Imaging (MRI) - the Lissajous navigator - was developed and quantitatively compared to the existing spherical navigator trajectory [1]. The spherical navigator cannot sample the complete spherical surface due to slew rate limitations of the scanner hardware. By utilizing a two dimensional Lissajous figure which is projected onto the spherical surface, the Lissajous navigator overcomes this limitation. The complete sampling of the sphere consequently leads to rotation estimates with higher and more isotropic accuracy. Simulations and phantom measurements were performed for both navigators. Both simulations and measurements show a significantly higher overall accuracy of the Lissajous navigator and a higher isotropy of the rotation estimates. Measured under identical conditions with identical postprocessing, the measured mean absolute error of the rotation estimates for the Lissajous navigator was 38% lower (0.3 ) than for the spherical navigator (0.5 ). The maximum error of the Lissajous navigator was reduced by 48% relative to the spherical navigator. The Lissajous navigator delivers higher accuracy of rotation estimation and a higher degree of isotropy than the spherical navigator with no evident drawbacks; these are two decisive advantages, especially for high-resolution anatomical imaging.
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. PMID:19928105
Aoun, Bachir
2016-05-01
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 modeling, 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. In addition, 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. PMID:26800289
Borazjani, Iman; Ge, Liang; Sotiropoulos, Fotis
2008-08-10
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 FSI
On the orbital stability of pendulum-like vibrations of a rigid body carrying a rotor
Yehia, Hamad M.; El-Hadidy, E. G.
2013-09-01
One of the most notable effects in mechanics is the stabilization of the unstable upper equilibrium position of a symmetric body fixed from one point on its axis of symmetry, either by giving the body a suitable angular velocity or by adding a suitably spinned rotor along its axis. This effect is widely used in technology and in space dynamics. The aim of the present article is to explore the effect of the presence of a rotor on a simple periodic motion of the rigid body and its motion as a physical pendulum. The equation in the variation for pendulum vibrations takes the form in which α depends on the moments of inertia, ρ on the gyrostatic momentum of the rotor and ν (the modulus of the elliptic function) depends on the total energy of the motion. This equation, which reduces to Lame's equation when ρ = 0, has not been studied to any extent in the literature. The determination of the zones of stability and instability of plane motion reduces to finding conditions for the existence of primitive periodic solutions (with periods 4 K( ν), 8 K( ν)) with those parameters. Complete analysis of primitive periodic solutions of this equation is performed analogously to that of Ince for Lame's equation. Zones of stability and instability are determined analytically and illustrated in a graphical form by plotting surfaces separating them in the three-dimensional space of parameters. The problem is also solved numerically in certain regions of the parameter space, and results are compared to analytical ones.
Slaughter, Chris; Bagwell, Justin; Checkles, Costa; Sentis, Luis; Vishwanath, Sriram
2011-01-01
Motivated by an emerging theory of robust low-rank matrix representation, in this paper, we introduce a novel solution for online rigid-body motion registration. The goal is to develop algorithmic techniques that enable a robust, real-time motion registration solution suitable for low-cost, portable 3-D camera devices. Assuming 3-D image features are tracked via a standard tracker, the algorithm first utilizes Robust PCA to initialize a low-rank shape representation of the rigid body. Robust PCA finds the global optimal solution of the initialization, while its complexity is comparable to singular value decomposition. In the online update stage, we propose a more efficient algorithm for sparse subspace projection to sequentially project new feature observations onto the shape subspace. The lightweight update stage guarantees the real-time performance of the solution while maintaining good registration even when the image sequence is contaminated by noise, gross data corruption, outlying features, and missing ...
Wu, Tse-Huai; Lee, Taeyoung
2015-01-01
This paper studies a rigid body attitude tracking control problem with attitude measurements only, when angular velocity measurements are not available. An angular velocity observer is constructed such that the estimated angular velocity is guaranteed to converge to the true angular velocity asymptotically from almost all initial estimates. As it is developed directly on the special orthogonal group, it completely avoids singularities, complexities, or discontinuities caused by minimal attitu...
New solvable problems in the dynamics of a rigid body about a fixed point in a potential field
Yehia, Hamad M.
2013-01-01
We determine the general form of the potential of the problem of motion of a rigid body about a fixed point, which allows the angular velocity to remain permanently in a principal plane of inertia of the body. Explicit solution of the problem of motion is reduced to inversion of a single integral. A several-parameter generalization of the classical case due to Bobylev and Steklov is found. Special cases solvable in elliptic and ultraelliptic functions of time are discussed.
Marcello Romano
2012-01-01
New exact analytic solutions are introduced for the rotational motion of a rigid body having two equal principal moments of inertia and subjected to an external torque which is constant in magnitude. In particular, the solutions are obtained for the following cases: (1) Torque parallel to the symmetry axis and arbitrary initial angular velocity; (2) Torque perpendicular to the symmetry axis and such that the torque is rotating at a constant rate about the symmetry axis, and arbitrary initial ...
Romano, Marcello
2008-08-01
New exact analytic solutions are introduced for the rotational motion of a rigid body having two equal principal moments of inertia and subjected to an external torque which is constant in magnitude. In particular, the solutions are obtained for the following cases: (1) Torque parallel to the symmetry axis and arbitrary initial angular velocity; (2) Torque perpendicular to the symmetry axis and such that the torque is rotating at a constant rate about the symmetry axis, and arbitrary initial angular velocity; (3) Torque and initial angular velocity perpendicular to the symmetry axis, with the torque being fixed with the body. In addition to the solutions for these three forced cases, an original solution is introduced for the case of torque-free motion, which is simpler than the classical solution as regards its derivation and uses the rotation matrix in order to describe the body orientation. This paper builds upon the recently discovered exact solution for the motion of a rigid body with a spherical ellipsoid of inertia. In particular, by following Hestenes’ theory, the rotational motion of an axially symmetric rigid body is seen at any instant in time as the combination of the motion of a “virtual” spherical body with respect to the inertial frame and the motion of the axially symmetric body with respect to this “virtual” body. The kinematic solutions are presented in terms of the rotation matrix. The newly found exact analytic solutions are valid for any motion time length and rotation amplitude. The present paper adds further elements to the small set of special cases for which an exact solution of the rotational motion of a rigid body exists.
Lohr, M. B.
2008-10-01
The rotational motion of a torque-free axisymmetric rigid body is precession. This motion has been expressed analytically in the literature given the body's initial orientation and rotational dynamics parameters, i.e. inertia ratio and initial angular velocities or precession parameters. The inverse problem of deriving these dynamics parameters given orientation in time has been implemented numerically but has not yet been solved analytically. If a rigid body is precessing, and its orientation with respect to an arbitrary inertial frame is provided at three equally spaced points in time such that the rotational motion is not undersampled, an analytical inverse solution is presented for the precession rate, relative spin rate, coning angle and angular velocities; if the precessional motion is due to inertial axisymmetry and torque-free motion, the inertia ratio is also derived. Additionally, an analytical methodology is presented to test for non-precessional motion. These techniques are applicable to various problems in space science and astronomy, where non-precessional motion or the rotational dynamics parameters of this type of rigid body must be accurately derived from its orientation or relative orientation in time.
Lācis, Uǧis; Taira, Kunihiko; Bagheri, Shervin
2016-01-01
Dispersion of low-density rigid particles with complex geometries is ubiquitous in both natural and industrial environments. We show that while explicit methods for coupling the incompressible Navier-Stokes equations and Newton's equations of motion are often sufficient to solve for the motion of cylindrical particles with low density ratios, for more complex particles - such as a body with a protrusion - they become unstable. We present an implicit formulation of the coupling between rigid body dynamics and fluid dynamics within the framework of the immersed boundary projection method. Similarly to previous work on this method, the resulting matrix equation in the present approach is solved using a block-LU decomposition. Each step of the block-LU decomposition is modified to incorporate the rigid body dynamics. We show that our method achieves second-order accuracy in space and first-order in time (third-order for practical settings), only with a small additional computational cost to the original method. Our implicit coupling yields stable solution for density ratios as low as 10-4. We also consider the influence of fictitious fluid located inside the rigid bodies on the accuracy and stability of our method.
International Nuclear Information System (INIS)
The rotational motion of a torque-free axisymmetric rigid body is precession. This motion has been expressed analytically in the literature given the body's initial orientation and rotational dynamics parameters, i.e. inertia ratio and initial angular velocities or precession parameters. The inverse problem of deriving these dynamics parameters given orientation in time has been implemented numerically but has not yet been solved analytically. If a rigid body is precessing, and its orientation with respect to an arbitrary inertial frame is provided at three equally spaced points in time such that the rotational motion is not undersampled, an analytical inverse solution is presented for the precession rate, relative spin rate, coning angle and angular velocities; if the precessional motion is due to inertial axisymmetry and torque-free motion, the inertia ratio is also derived. Additionally, an analytical methodology is presented to test for non-precessional motion. These techniques are applicable to various problems in space science and astronomy, where non-precessional motion or the rotational dynamics parameters of this type of rigid body must be accurately derived from its orientation or relative orientation in time
Multiple-Zone Diffractive Optic Element for Laser Ranging Applications
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
Dobson, G. J.
1998-07-01
Newton's treatment of the precession of the equinoxes in his Philosophiae Naturalis Principia Mathematica was recognised by d'Alembert in 1749 as being faulty, despite the very close agreement between Newton's calculated value for the rate of precesion and the observed value. Here, the author presents an analysis of Newton's geometrical methods applied in his treatment of precession and claims that it was basically flawed because Newton lacked knowledge of the principles of rigid body dynamics and, in particular, was unaware of the idea of angular momentum.
International Nuclear Information System (INIS)
This paper presents an algorithm for the efficient numerical analysis and simulation of modest to heavily constrained multi-rigid-body dynamic systems. The algorithm can accommodate the spatial motion of general multi-rigid-body systems containing arbitrarily many closed loops in O(n + m)operations overall for systems containing n generalized coordinates, and m independent algebraic constraints. The presented approach does not suffer from the performance (speed) penalty encountered by most other of the so-called 'O(n)' state-space formulations, when dealing with constraints which tend to actually show O(n + m + nm + nm2+ m3) performance. Additionally, these latter formulations may require additional constraint violation stabilization procedures (e.g. Baumgarte's method, coordinate partitioning, etc.) which can contribute significant additional computation. The presented method suffers less from this difficulty because the loop closure constraints at both the velocity and acceleration level are directly embedded within the formulation. Due to these characteristics, the presented algorithm offers superior computing performance relative to other methods in situations involving both large n and m
Directory of Open Access Journals (Sweden)
Ikuru Otomo
2014-04-01
Full Text Available In the field of design and manufacturing, there are many problems with managing dynamic states of three-dimensional (3D objects. In order to solve these problems, the four-dimensional (4D mesh model and its modeling system have been proposed. The 4D mesh model is defined as a 4D object model that is bounded by tetrahedral cells, and can represent spatio-temporal changes of a 3D object continuously. The 4D mesh model helps to solve dynamic problems of 3D models as geometric problems. However, the construction of the 4D mesh model is limited on the time-series 3D voxel data based method. This method is memory-hogging and requires much computing time. In this research, we propose a new method of constructing the 4D mesh model that derives from the 3D mesh model with continuous rigid body movement. This method is realized by making a swept shape of a 3D mesh model in the fourth dimension and its tetrahe-dralization. Here, the rigid body movement is a screwed movement, which is a combination of translational and rotational movement.
Romano, Marcello
2012-01-01
New exact analytic solutions are introduced for the rotational motion of a rigid body having two equal principal moments of inertia and subjected to an external torque which is constant in magnitude. In particular, the solutions are obtained for the following cases: (1) Torque parallel to the symmetry axis and arbitrary initial angular velocity; (2) Torque perpendicular to the symmetry axis and such that the torque is rotating at a constant rate about the symmetry axis, and arbitrary initial angular velocity; (3) Torque and initial angular velocity perpendicular to the symmetry axis, with the torque being fixed with the body. In addition to the solutions for these three forced cases, an original solution is introduced for the case of torque-free motion, which is simpler than the classical solution as regards its derivation and uses the rotation matrix in order to describe the body orientation. This paper builds upon the recently discovered exact solution for the motion of a rigid body with a spherical ellipso...
Lācis, Uǧis; Bagheri, Shervin
2015-01-01
Dispersion of low-density rigid particles with complex geometries is ubiquitous in both natural and industrial environments. We show that while explicit methods for coupling the incompressible Navier-Stokes equations and Newton's equations of motion are often sufficient to solve for the motion of cylindrical particles with low density ratios, for more complex particles - such as a body with a protrusion - they become unstable. We present an implicit formulation of the coupling between rigid body dynamics and fluid dynamics within the framework of the immersed boundary projection method. Similar to previous work on this method, the resulting matrix equation in the present approach is solved using a block-LU decomposition. Each step of the block-LU decomposition is modified to incorporate the rigid body dynamics. We show that our method achieves second-order accuracy in space and first-order in time (third-order for practical settings), only with a small additional computational cost to the original method. Our...
Mass of Rigid Body Real-Time Simulation on GPUs%基于GPU实现的大量刚体运动实时仿真
Institute of Scientific and Technical Information of China (English)
彭林春; 杨红雨; 杨光
2013-01-01
针对存在大量刚体运动的虚拟场景,提出一种基于在GPU上实现的实时仿真算法,利用GPU的并行计算能力,实时处理刚体交互,更新刚体状态.使用深度剥离技术,离散化刚体,并使其由一组具有相同大小的粒子表示.每一帧刚体间的运动交互则由粒子间的运动交互来实现.碰撞粒子对间的交互则用离散元法.通过统一网格方式,分割仿真域空间,以提高碰撞检测速率.实验证明,提出的新算法大幅度的提升了仿真大量刚体的速率.%In view of virtual scene where exist a mass of moving rigid bodies, we proposed a real - time rigid body simulation algorithm on CPU. This algorithm handles rigid body's interaction and status in real -time, utilizing the tremendous computational power provided by GPUs. We discretized rigid body using depth peeling, to making rigid body represented by a set of particles with the same size. We utilized particle pairs' interaction to realizing rigid body's interaction. Discrete element method was used to handle collision detection. And we discretized simulation areas across uniform grid to improve collision detection. The results show that this algorithm can improve the rigid body simulation speed largely.
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
Ershkov, Sergey V
2014-01-01
Here is presented a new exact solution of Euler's equations (rigid body dynamics, non-zero applied torques) in the case of reduction one of Euler's equations to a proper Abel ordinary differential equation. One component of angular velocity of rigid body for such a solution - is a proper classical solution for the case of symmetric rigid rotor (which has two equal moments of inertia), but applied torques is not zero. The 2-nd component is proved to be appropriate solution of Abel ordinary differential equation. Due to a very special character of Riccati's type equation (such as Abel ODE), its general solution is known to have a proper gap of above component of angular velocity of rigid body. It means a possibility of sudden acceleration of rigid body rotation around appropriate principal axe at definite moment of parametrical time. The 3-d could be obtained from a simple algebraic equality. It is a multiplying all the components of angular velocity of rigid body (which is to be a constant for such a solution)...
Wu, Shunguang; Hong, Lang
2008-04-01
A framework of simultaneously estimating the motion and structure parameters of a 3D object by using high range resolution (HRR) and ground moving target indicator (GMTI) measurements with template information is given. By decoupling the motion and structure information and employing rigid-body constraints, we have developed the kinematic and measurement equations of the problem. Since the kinematic system is unobservable by using only one scan HRR and GMTI measurements, we designed an architecture to run the motion and structure filters in parallel by using multi-scan measurements. Moreover, to improve the estimation accuracy in large noise and/or false alarm environments, an interacting multi-template joint tracking (IMTJT) algorithm is proposed. Simulation results have shown that the averaged root mean square errors for both motion and structure state vectors have been significantly reduced by using the template information.
Institute of Scientific and Technical Information of China (English)
JianhuaCHENG; JunfengLI; 等
1996-01-01
In this paper a mnechanical system is studied in which a rotor rotates around a fixed axis with a string suspended symmetric rigid body.All relative equilibrium strates and their stability are discussed.Considering the spinning angular velocity ω around the fixed vertical axis as a parameter,algebraic equations with this parameter are obtained,Every solution of the equations is relevant to a relative equilibrium state of the system.The existence of two important relative equilibrium states is discussed by numerical method developed in bifurcation theory in this paper,In addition,The lagrange's Theorem is used to determine the stability of the relative equilibrium state relevant to the solution of the algebraic equations.
Rotation of the Earth as a Triaxial Rigid Body%三轴刚性地球体的旋转
Institute of Scientific and Technical Information of China (English)
申文斌; 陈巍; 王文均; 梁毅强
2007-01-01
The Earth is taken as a triaxial rigid body, which rotates freely in the Euclidian space. The starting equations are the Euler dynamic equations, with A smaller than B and B smaller than C. The Euler equations are solved, and the numerical results are provided. In the calculations, the following parameters are used: (C-B)/A=0.003 273 53; (B-A)/C=0.000 021 96:(C-A)/B=0.003 295 49, and the mean angular velocity of the Earth's rotation, ω =0.000 072 921 15 rad/s. Calculations show that, besides the self-rotation of the Earth and the free Euler procession of its rotation, there exists the free nutation:the nutation angle, or the angle between the Earth's momentary rotation axis and the mean axis that periodically change with time. The free nutation is investigated.
Knowledge-in-action: a study on the integration of forces and energy in a rigid body
Directory of Open Access Journals (Sweden)
Consuelo Escudero
2009-03-01
Full Text Available This paper intends to go on with the study of problem solving in a compatible way with the theories of conceptual fields (TCC of Vergnaud (1990,1994,1998 and mental models of Johnson-Laird (1983,1990. Together with findings of another study (Escudero & Jaime 2007, some achievements and difficulties of freshmore engineering students when solving problems of the motion of rigid body in terms of the knowledge-in-action are analysed. The research methodology under a qualitative paradigm grouped data into categories which are not provided a priori by the theoretical framework. It can be said that the quality of the conceptual representation has been explicit in the quality of the proposed solution. Some meanings introduced by students in their problem solving activities can be characterized as operational invariants.
Chi, Heng; Lopez-Pamies, Oscar; Paulino, Glaucio H.
2016-02-01
This paper presents a new variational principle in finite elastostatics applicable to arbitrary elastic solids that may contain constitutively rigid spatial domains (e.g., rigid inclusions). The basic idea consists in describing the constitutive rigid behavior of a given spatial domain as a set of kinematic constraints over the boundary of the domain. From a computational perspective, the proposed formulation is shown to reduce to a set of algebraic constraints that can be implemented efficiently in terms of both single-field and mixed finite elements of arbitrary order. For demonstration purposes, applications of the proposed rigid-body-constraint formulation are illustrated within the context of elastomers, reinforced with periodic and random distributions of rigid filler particles, undergoing finite deformations.
Energy Technology Data Exchange (ETDEWEB)
Cardou, Philippe, E-mail: pcardou@cim.mcgill.ca; Angeles, Jorge [McGill University, Macdonald Engineering Building, Department of Mechanical Engineering, Centre for Intelligent Machines (Canada)
2008-05-15
Two methods are available for the estimation of the angular velocity of a rigid body from point-acceleration measurements: (i) the time-integration of the angular acceleration and (ii) the square-rooting of the centripetal acceleration. The inaccuracy of the first method is due mainly to the accumulation of the error on the angular acceleration throughout the time-integration process, which does not prevent that it be used successfully in crash tests with dummies, since these experiments never last more than one second. On the other hand, the error resulting from the second method is stable through time, but becomes inaccurate whenever the rigid body angular velocity approaches zero, which occurs in many applications. In order to take advantage of the complementarity of these two methods, a fusion of their estimates is proposed. To this end, the accelerometer measurements are modeled as exact signals contaminated with bias errors and Gaussian white noise. The relations between the variables at stake are written in the form of a nonlinear state-space system in which the angular velocity and the angular acceleration are state variables. Consequently, a minimum-variance-error estimate of the state vector is obtained by means of extended Kalman filtering. The performance of the proposed estimation method is assessed by means of simulation. Apparently, the resulting estimation method is more robust than the existing accelerometer-only methods and competitive with gyroscope measurements. Moreover, it allows the identification and the compensation of any bias error in the accelerometer measurements, which is a significant advantage over gyroscopes.
International Nuclear Information System (INIS)
Two methods are available for the estimation of the angular velocity of a rigid body from point-acceleration measurements: (i) the time-integration of the angular acceleration and (ii) the square-rooting of the centripetal acceleration. The inaccuracy of the first method is due mainly to the accumulation of the error on the angular acceleration throughout the time-integration process, which does not prevent that it be used successfully in crash tests with dummies, since these experiments never last more than one second. On the other hand, the error resulting from the second method is stable through time, but becomes inaccurate whenever the rigid body angular velocity approaches zero, which occurs in many applications. In order to take advantage of the complementarity of these two methods, a fusion of their estimates is proposed. To this end, the accelerometer measurements are modeled as exact signals contaminated with bias errors and Gaussian white noise. The relations between the variables at stake are written in the form of a nonlinear state-space system in which the angular velocity and the angular acceleration are state variables. Consequently, a minimum-variance-error estimate of the state vector is obtained by means of extended Kalman filtering. The performance of the proposed estimation method is assessed by means of simulation. Apparently, the resulting estimation method is more robust than the existing accelerometer-only methods and competitive with gyroscope measurements. Moreover, it allows the identification and the compensation of any bias error in the accelerometer measurements, which is a significant advantage over gyroscopes
Multiple zone power forwards. A value at risk framework
International Nuclear Information System (INIS)
Over the 1990s, deregulated power markets in New-England provided zones with fluctuating spot prices. Such prices have a notoriously high volatility, owing to the difficulty of storing electrical energy and the delays needed to adjust generation levels. In this context, forward contracts have become increasingly popular and understanding their dynamic is a problem facing many market players. This paper proposes a parsimonious parametric model, based on the price series of all n-month forward contracts (n = 1,2,3..), encompassing multiple zones. The model is then used for value at risk forecasts, which are backtested and compared with the ones in use by the risk management unit of an important electricity producer. Extensions to include natural gas and power-relevant oil-based future markets are discussed. (author)
Nagasaka, Imao; Ishida, Yukio; Koyama, Takayuki; Fujimatsu, Naoki
Currently, some kinds of helicopters use pendulum absorbers in order to reduce vibrations. Present pendulum absorbers are designed based on the antiresonance concept used in the linear theory. However, since the vibration amplitudes of the pendulum are not small, it is considered that the nonlinearity has influence on the vibration characteristics. Therefore, the best suppression cannot be attained by using the linear theory. In a helicopter, periodic forces act on the blades due to the influences of the air thrust. These periodic forces act on the blades with the frequency which is the integer multiple of the rotational speed of the rotor. Our previous study proposed a 2-degree-of-freedom (2DOF) model composed of a rotor blade and a pendulum absorber. The blade was considered as a rigid body and it was excited by giving a sinusoidal deflection at its end. The present paper proposes a 3DOF model that is more similar to the real helicopter, since the freedom of the fuselage is added and the periodic forces are applied to the blade by aerodynamic force. The vibration is analyzed considering the nonlinear characteristics. The resonance curves of rotor blades with pendulum absorbers are obtained analytically and experimentally. It is clarified that the most efficient condition is obtained when the natural frequency of the pendulum is a little bit different from the frequency of the external force. Various unique nonlinear characteristics, such as bifurcations, are also shown.
Directory of Open Access Journals (Sweden)
José Fermi Guerrero-Castellanos
2015-08-01
Full Text Available The present paper deals with the development of bounded feedback control laws mimicking the strategy adopted by flapping flyers to stabilize the attitude of systems falling within the framework of rigid bodies. Flapping flyers are able to orient their trajectory without any knowledge of their current attitude and without any attitude computation. They rely on the measurements of some sensitive organs: halteres, leg sensilla and magnetic sense, which give information about their angular velocity and the orientation of gravity and magnetic field vectors. Therefore, the proposed feedback laws are computed using direct inertial sensors measurements, that is vector observations with/without angular velocity measurements. Hence, the attitude is not explicitly required. This biomimetic approach is very simple, requires little computational power and is suitable for embedded applications on small control units. The boundedness of the control signal is taken into consideration through the design of the control laws by saturation of the actuators’ input. The asymptotic stability of the closed loop system is proven by Lyapunov analysis. Real-time experiments are carried out on a quadrotor using MEMS inertial sensors in order to emphasize the efficiency of this biomimetic strategy by showing the convergence of the body’s states in hovering mode, as well as the robustness with respect to external disturbances.
Feng, Bing; Gifford, Howard C.; Beach, Richard D.; Boening, Guido; Gennert, Michael A.; King, Michael A.
2006-01-01
Due to the extended imaging times employed in SPECT and PET, patient motion during imaging is a common clinical occurrence. The fast and accurate correction of the three-dimensional (3D) translational and rotational patient motion in iterative reconstruction is thus necessary to address this important cause of artifacts. We propose a method of incorporating 3D Gaussian interpolation in the projector/backprojector pair to facilitate compensation for rigid-body motion in addition to attenuation...
Feng, Bing; King, Michael A.
2006-01-01
We developed a unique method for estimating and compensating rigid-body translations and rotations from scatter and-attenuation-compensated projection data in iterative reconstruction when multiple projection angles are acquired at the same time. During reconstruction, both the non-attenuated and attenuated line-integrals are calculated. Their ratios are then multiplied to the scatter-corrected projection data to estimate scatter-and-attenuation- compensated projection data. At the end of eac...
Romano, Marcello
2008-01-01
The exact analytic solution is introduced for the rotational motion of a rigid body having three equal principal moments of inertia and subjected to an external torque velocity which is constant for an observer fixed with the body, and to arbitrary initial angular velocity. In the paper a parametrization of the rotation by three complex numbers is used. In particular, the rows of the rotation matrix are seen as elements of the unit sphere and projected, by stereographic projection, onto poi...
Czech Academy of Sciences Publication Activity Database
Nečasová, Šárka; Wolf, J.
2016-01-01
Roč. 36, č. 3 (2016), s. 1539-1562. ISSN 1078-0947 R&D Projects: GA ČR GA13-00522S Institutional support: RVO:67985840 Keywords : incompressible fluid * motion of rigid body * strong solutions Subject RIV: BA - General Mathematics Impact factor: 0.826, year: 2014 http://www.aimsciences.org/journals/displayArticlesnew.jsp?paperID=11589
Energy Technology Data Exchange (ETDEWEB)
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.
International Nuclear Information System (INIS)
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
Directory of Open Access Journals (Sweden)
Pål Johan From
2012-04-01
Full Text Available This paper presents the explicit dynamic equations of a mechanical system. The equations are presented so that they can easily be implemented in a simulation software or controller environment and are also well suited for system and controller analysis. The dynamics of a general mechanical system consisting of one or more rigid bodies can be derived from the Lagrangian. We can then use several well known properties of Lie groups to guarantee that these equations are well defined. This will, however, often lead to rather abstract formulation of the dynamic equations that cannot be implemented in a simulation software directly. In this paper we close this gap and show what the explicit dynamic equations look like. These equations can then be implemented directly in a simulation software and no background knowledge on Lie theory and differential geometry on the practitioner's side is required. This is the first of two papers on this topic. In this paper we derive the dynamics for single rigid bodies, while in the second part we study multibody systems. In addition to making the equations more accessible to practitioners, a motivation behind the papers is to correct a few errors commonly found in literature. For the first time, we show the detailed derivations and how to arrive at the correct set of equations. We also show through some simple examples that these correspond with the classical formulations found from Lagrange's equations. The dynamics is derived from the Boltzmann--Hamel equations of motion in terms of local position and velocity variables and the mapping to the corresponding quasi-velocities. Finally we present a new theorem which states that the Boltzmann--Hamel formulation of the dynamics is valid for all transformations with a Lie group topology. This has previously only been indicated through examples, but here we also present the formal proof. The main motivation of these papers is to allow practitioners not familiar with
Romano, Marcello
2008-03-01
The exact analytic solution is introduced for the rotational motion of a rigid body having three equal principal moments of inertia and subjected to an external torque vector which is constant for an observer fixed with the body, and to arbitrary initial angular velocity. In the paper a parametrization of the rotation by three complex numbers is used. In particular, the rows of the rotation matrix are seen as elements of the unit sphere and projected, by stereographic projection, onto points on the complex plane. In this representation, the kinematic differential equation reduces to an equation of Riccati type, which is solved through appropriate choices of substitutions, thereby yielding an analytic solution in terms of confluent hypergeometric functions. The rotation matrix is recovered from the three complex rotation variables by inverse stereographic map. The results of a numerical experiment confirming the exactness of the analytic solution are reported. The newly found analytic solution is valid for any motion time length and rotation amplitude. The present paper adds a further element to the small set of special cases for which an exact solution of the rotational motion of a rigid body exists.
Pathak, Ashish; Raessi, Mehdi
2014-11-01
We present a 3D MPI-parallel, GPU-accelerated computational tool that captures the interaction between a moving rigid body and two-fluid flows. Although the immediate application is the study of ocean wave energy converters (WECs), the model was developed at a general level and can be used in other applications. Solving the full Navier-Stokes equations, the model is able to capture non-linear effects, including wave-breaking and fluid-structure interaction, that have significant impact on WEC performance. To transport mass and momentum, we use a consistent scheme that can handle large density ratios (e.g. air/water). We present a novel reconstruction scheme for resolving three-phase (solid-liquid-gas) cells in the volume-of-fluid context, where the fluid interface orientation is estimated via a minimization procedure, while imposing a contact angle. The reconstruction allows for accurate mass and momentum transport in the vicinity of three-phase cells. The fast-fictitious-domain method is used for capturing the interaction between a moving rigid body and two-fluid flow. The pressure Poisson solver is accelerated using GPUs in the MPI framework. We present results of an array of test cases devised to assess the performance and accuracy of the computational tool.
Romano, Marcello
2012-01-01
The exact analytic solution is introduced for the rotational motion of a rigid body having three equal principal moments of inertia and subjected to an external torque vector which is constant for an observer fixed with the body, and to arbitrary initial angular velocity. In the paper a parametrization of the rotation by three complex numbers is used. In particular, the rows of the rotation matrix are seen as elements of the unit sphere and projected, by stereographic projection, onto points on the complex plane. In this representation, the kinematic differential equation reduces to an equation of Riccati type, which is solved through appropriate choices of substitutions, thereby yielding an analytic solution in terms of confluent hypergeometric functions. The rotation matrix is recovered from the three complex rotation variables by inverse stereographic map. The results of a numerical experiment confirming the exactness of the analytic solution are reported. The newly found analytic solution is valid for any...
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. PMID:27318041
Connolly, C. M.; Konik, A.; Dasari, P. K. R.; Segars, P.; Zheng, S.; Johnson, K. L.; Dey, J.; King, M. A.
2011-03-01
Patient motion can cause artifacts, which can lead to difficulty in interpretation. The purpose of this study is to create 3D digital anthropomorphic phantoms which model the location of the structures of the chest and upper abdomen of human volunteers undergoing a series of clinically relevant motions. The 3D anatomy is modeled using the XCAT phantom and based on MRI studies. The NURBS surfaces of the XCAT are interactively adapted to fit the MRI studies. A detailed XCAT phantom is first developed from an EKG triggered Navigator acquisition composed of sagittal slices with a 3 x 3 x 3 mm voxel dimension. Rigid body motion states are then acquired at breath-hold as sagittal slices partially covering the thorax, centered on the heart, with 9 mm gaps between them. For non-rigid body motion requiring greater sampling, modified Navigator sequences covering the entire thorax with 3 mm gaps between slices are obtained. The structures of the initial XCAT are then adapted to fit these different motion states. Simultaneous to MRI imaging the positions of multiple reflective markers on stretchy bands about the volunteer's chest and abdomen are optically tracked in 3D via stereo imaging. These phantoms with combined position tracking will be used to investigate both imaging-data-driven and motion-tracking strategies to estimate and correct for patient motion. Our initial application will be to cardiacperfusion SPECT imaging where the XCAT phantoms will be used to create patient activity and attenuation distributions for each volunteer with corresponding motion tracking data from the markers on the body-surface. Monte Carlo methods will then be used to simulate SPECT acquisitions, which will be used to evaluate various motion estimation and correction strategies.
Institute of Scientific and Technical Information of China (English)
王瑾; 孙宁
2012-01-01
针对三维空间,提出了一种可以同时测量刚体9个惯性参数的新方法.利用气体静压轴承低速自由转动时其角速度是一个随时间衰减的单指数函数这一运动规律,测量物体绕任意的转动惯量,通过9次测量最终求出刚体的9个惯性参数.设计了一套物体惯性参数测量仪,该测量仪可以同时测量三维空间中物体的9个惯性参数.测量过程中无需重新装配,减少了中间测试量及人为干预误差,使测量时间缩短,测量精度提高.%For three-dimensional space, a new method which can measure the nine inertial parameters of a rigid body simultaneously is proposed. With the law of motion that when aerostatic bearing move slowly its angular velocity is a single exponential function decayed with time, the moment of inertia of the rigid body rotating a axis in an arbitrary direction is obtained, through nine measurements, the inertial parameters of a rigid body can be got finally. A set of instrument used for measuring the rigid body inertial parameters is designed. This instrument can measure the nine inertial parameters of a rigid body in three-dimensional space simultaneously. There' s no need to re-assembly in the process of measurement, so intermediate testing quantity, error made by human and measuring time are all reduced.
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.
McBride, Carl; Noya, Eva G.; Vega, Carlos
2013-03-01
Here we provide FORTRAN source code to facilitate the calculation of the “Noya-Vega-McBride” (NVM) rotational propagator for asymmetric tops [E.G. Noya, C. Vega, C. McBride, J. Chem. Phys. 134 (2011) 054117] for a given value of PT and A, B and C, where P is the number of beads, T is the temperature, and A, B and C are the rotational constants for the system in question. The resulting NVM propagator calculated by the code provided can then be used to obtain the quantum rotational energy during a path integral Monte Carlo simulation of rigid bodies. Catalogue identifier: AEOA_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEOA_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 624734 No. of bytes in distributed program, including test data, etc.: 9890026 Distribution format: tar.gz Programming language: Fortran. Computer: Any. Operating system: Any. RAM: code included in the distribution package). Nature of problem: Calculation of the NVM rotational propagator Solution method: Fortran implementation of the NVM propagator equation. Additional comments: Example and test calculations are provided. Running time: 2-200 hours. Two examples are provided. The PT_1497 example will take approximately 11 hours to run. The quick_test should only take a few minutes.
Energy Technology Data Exchange (ETDEWEB)
Inoue, Minoru; Yoshimura, Michio, E-mail: myossy@kuhp.kyoto-u.ac.jp; Sato, Sayaka; Nakamura, Mitsuhiro; Yamada, Masahiro; Hirata, Kimiko; Ogura, Masakazu; Hiraoka, Masahiro [Department of Radiation Oncology and Image-Applied Therapy, Kyoto University Graduate School of Medicine, Kyoto 606-8507 (Japan); Sasaki, Makoto; Fujimoto, Takahiro [Division of Clinical Radiology Service, Kyoto University Hospital, Kyoto 606-8507 (Japan)
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.
Institute of Scientific and Technical Information of China (English)
李学相; 安学庆
2012-01-01
现有的非刚体三维运动重建算法很难根据不同的场景、不同的非刚体来寻找不同的形状基,这种情况对重建过程产生了很大的影响,造成模型失真.为了解决这一问题,提出一种基于Murkowski距离连续的非刚体三维运动恢复算法,该算法根据在高速分解的图像序列中帧与帧之间的运动参数与特征点位移变化都呈现连续平缓的物理特性,在Murkowski距离约束的情况下,将运动结构参数通过非线性优化的方法来进行求解,最终得到非刚体的三维运动结构,并且通过仿真实验,验证了它的可行.%The existing non rigid body three dimensional motion reconstruction algorithm is difficult to find different shapes according to different scene and different non rigid body mus,and this kind of situation will exert great influence on the reconstruction process,cause model distortion. In order to solve this problem, this paper put forward a murkowski distance based continuous non rigid body three dimensional movement recovery algorithm, which presents continuous physical characteristics on the decomposition of image sequence of frame and frame between the movement parameters and feature point displacement change. Using the physical characteristics will solve motion structure parameter in Murkowski range bound through the nonlinear optimization method, and get the non rigid body 3D motion structure, and the experiment shows that simulation verification results are feasible.
Energy Technology Data Exchange (ETDEWEB)
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.
International Nuclear Information System (INIS)
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
Feng, Bing; King, Michael A
2006-11-01
We developed a unique method for estimating and compensating rigid-body translations and rotations from scatter and-attenuation-compensated projection data in iterative reconstruction when multiple projection angles are acquired at the same time. During reconstruction, both the non-attenuated and attenuated line-integrals are calculated. Their ratios are then multiplied to the scatter-corrected projection data to estimate scatter-and-attenuation- compensated projection data. At the end of each iteration, the sets of compensated projection data for the angles acquired at the same time are employed to calculate the center-of mass and the inertia tensor, which are used to estimate the location and orientation of the imaging object by the principle-axes method. The estimated motion is applied in the next iteration to reposition the estimated slices and attenuation map in the projector and back-projector to match the pose of the patient at time the projections were acquired. To evaluate our method, we simulated an acquisition of the MCAT phantom with a 3-head SPECT system and imaged the Data Spectrum anthropomorphic phantom on a 3-head IRIX SPECT system. In simulations the phantom translated and rotated by the same amount 9 times. A numerical projector modeling the motion, attenuation, and distance-dependent blurring was used to generate the projection data. Poisson noise was added and 30 noise-realizations were generated. In the experiment with the anthropomorphic phantom, four 360-degree acquisitions were performed with the phantom translated or rotated beforehand. A motion-present dataset was made by mixing the 4 acquisitions. For both the MCAT phantom simulations and anthropomorphic phantom experiment, the motion-present data were reconstructed with 10 iterations of the OSEM which estimates and corrects the motion as described above. Our method obtained visually artifact-free reconstructions, while the reconstruction with no motion correction showed severe artifacts
Institute of Scientific and Technical Information of China (English)
熊国华; 蔡建乐; 撒凤杰
2011-01-01
利用3DS MAX及Cult 3D软件操作平台,先建立三维虚拟的刚体转动实验仪器模型,再使用Cult 3D Designer编辑器,通过组织事件、动作与对象的关联编程,实现了该实验的复杂交互动作.完成基于交互式虚拟技术的刚体转动实验浏览与操纵系统.%The service platforms of 3DS MAX and Cult 3D software were used. Firstly, the dummy model of rotational rigid body experiment was made. Then the Cult 3D Designer editor was made use of to realize the complex interactive operation through programming the relevance among event, motion and object. Finally, the browse and manipulative system of rotational rigid body experiment, which is based on interactive VR technology, is completed.
Energy Technology Data Exchange (ETDEWEB)
Takayama, Yuki; Schwieters, Charles D.; Grishaev, Alexander; Ghirlando, Rodolfo; Clore, G. Marius (NIH)
2012-10-23
The first component of the bacterial phosphotransferase system, enzyme I (EI), is a multidomain 128 kDa dimer that undergoes large rigid-body conformational transitions during the course of its catalytic cycle. Here we investigate the solution structure of a non-phosphorylatable active-site mutant in which the active-site histidine is substituted by glutamine. We show that perturbations in the relative orientations and positions of the domains and subdomains can be rapidly and reliably determined by conjoined rigid-body/torsion angle/Cartesian simulated annealing calculations driven by orientational restraints from residual dipolar couplings and shape and translation information afforded by small- and wide-angle X-ray scattering. Although histidine and glutamine are isosteric, the conformational space available to a Gln side chain is larger than that for the imidazole ring of His. An additional hydrogen bond between the side chain of Gln189 located on the EIN{sup {alpha}/{beta}} subdomain and an aspartate (Asp129) on the EIN{sup {alpha}} subdomain results in a small ({approx}9{sup o}) reorientation of the EIN{sup {alpha}} and EIN{sup {alpha}/{beta}} subdomains that is in turn propagated to a larger reorientation ({approx}26{sup o}) of the EIN domain relative to the EIC dimerization domain, illustrating the positional sensitivity of the EIN domain and its constituent subdomains to small structural perturbations.
Development and characterization of an automatic technique for the alignment of fMRI time series.
Ciulla, C; Deek, F P
2001-01-01
An automatic technique for the registration of fMRI time series has been developed, implemented and tested. The method assumes the human brain to be a rigid body and computes a head coordinate system on the basis of three reference points that lies on the directions corresponding to two of the principal axes of the volume at the intersections with the head boundary. Such directions are found computing the eigenvectors of the symmetric inertia matrix of the image. The inertia components were extracted weighting pixels' coordinates with their intensity values. The three reference points were found in the same position, relative to the head, in both the test and the reference images. The technique has been tested using T2*-weighted Magnetic Resonance (MR) images in which known rigid body transformations have been applied. The results obtained indicate that the method offers subvoxel accuracy in correcting misalignment among time points in fMRI time series. PMID:11599532
Experimental investigation of a single-plane automatic balancing mechanism for a rigid rotor
Rodrigues, DJ; Champneys, AR; Friswell, MI; Wilson, RE
2010-01-01
We present an experimental investigation of a single-plane automatic balancer that is fitted to a rigid rotor. Two balls, which are free to travel around a circular race, are used to compensate for the mass imbalance in the plane of the device. The experimental rig possesses both cylindrical and conical rigid body modes and the performance of the automatic balancer is assessed for a variety of different levels of imbalance. A non-planar mathematical model that also includes the observed effec...
Institute of Scientific and Technical Information of China (English)
侯健; 张方方
2012-01-01
为研究非标准条件下高速旋转弹丸的刚体外弹道性能,基于坐标变换理论建立了地球曲率影响下的外弹道数学模型,分析了自然风对弹丸气动力及气动力矩的作用,并在考虑气温气压及重力加速度变化的基础上得到了非标准务件下旋转弹丸的刚体外弹道模型.利用该模型对某105 mm榴弹外弹道进行仿真,结果表明:地球曲率引起旋转弹丸外弹道性能参数值少量增加,且增加量随弹丸射程的增大而增加,验证了自然风对弹丸动态稳定性有较大影响,进而影响弹丸的各弹道参数的结论.%To study the rigid body external trajectory performance of spinning projectile under non-standard conditions,the effect of natural wind on earth curvature was analyzed. Moreover,a rigid body external trajectory model was established according to the variations in atmospheric pressure,temperature and acceleration of gravity. The simulation was carried out on the external trajectory of a 105 mm shrapnel by this model. The calculated results show that the external trajectory performance parameters are increased with the fire range by earth curvature,thereby verifying the influence of natural wind upon the dynamical stability of the projectile,which further affects the external trajectory performance parameters.
International Nuclear Information System (INIS)
The no-type curve with negative skin of a horizontal well has been found in the current research. Negative skin is very significant to transient well test and rate decline analysis. This paper first presents the negative skin problem where the type curves with negative skin of a horizontal well are oscillatory. In order to solve the problem, we propose a new model of transient well test and rate decline analysis for a horizontal well in a multiple-zone composite reservoir. A new dimensionless definition of rD is introduced in the dimensionless mathematical modelling under different boundaries. The model is solved using the Laplace transform and separation of variables techniques. In Laplace space, the solutions for both constant rate production and constant wellbore pressure production are expressed in a unified formula. We provide graphs and thorough analysis of the new standard type curves for both well test and rate decline analysis; the characteristics of type curves are the reflections of horizontal well production in a multiple-zone reservoir. An important contribution of our paper is that our model removed the oscillation in type curves and thus solved the negative skin problem. We also show that the characteristics of type curves depend heavily on the properties of different zones, skin factor, well length, formation thickness, etc. Our research can be applied to a real case study
用四元数描述飞行器姿态时的几个基本问题%The Key Problems of Describing Rigid-Body Attitude by Using Quaternion
Institute of Scientific and Technical Information of China (English)
范奎武
2012-01-01
讨论描述刚体空间姿态的欧拉—克雷洛夫角、方向余弦矩阵、四元数这三种方法,给出方向余弦矩阵与四元数之间关系的推导方法,推导并验证了合成转动四元数的求取方法,介绍了通过方向余弦矩阵推导四元数微分方程的方法.%The three methods of describing rigid-body spatial attitude by using Euler-krylov angle , direction cosine matrix and quaternion are discussed firstly, then the derivation of relationship between direction' cosine matrix and quaternion is presented, in which the algorithm method of resultant rotation quaternion is deduced and verified. Finally, the derivation method of quaternion differential equation by using direction cosine matrix is proposed in detail.
Rigid body essential X-ray crystallography
DEFF Research Database (Denmark)
Bjerrum, Esben Jannik; Biggin, Philip C
2008-01-01
The ligand-binding domain (LBD) from the ionotropic glutamate receptor subtype 2 (GluR2) has been shown to adopt a range of ligand-dependent conformational states. These states have been described in terms of the rotation required to fit subdomain (lobe) 2 following superposition of subdomain (lo...
The rigid body obliquity history of mars
International Nuclear Information System (INIS)
The primary objective of this study is to explore the range of uncertainty in the obliquity history of Mars associated with the present uncertainty in the axial precession rate. The obliquity, or angular separation between the spin axis and the orbit normal, is the most important parameter for determining the seasonal and latitudinal pattern of insolation. Thus significant variations in obliquity are a likely source of major climatic variations on Mars. The present obliquity is well known, and the torques acting to reorient the spin axis of Mars can be readily calculated for time spans of order 107 years into the past (or future). The primary limitation to reconstructing the obliquity history is uncertainty in the mean moment of inertial of Mars, which governs its response to the applied torques. The range of axial precession rates corresponding to recent theoretical estimates of the moment of inertial is 8.29-8.77 arc sec/yr, but even the most recent observational limits are still much broader: 8-12 arc sec/yr. Nominal estimates of the axial precession rate suggest that resonant amplification of a number of small terms in the orbital inclination series will lead to significant variations in the obliquity of Mars, a behavior much different from the Earth. The major variations are on a 105 year time scale, with significant amplitude modulation on a 106 year time scale. Because of this resonant amplification, estimates of the obliquity history depend very sensitively on assumed values for the axial precession rate. Three different analytic techniques are applied to the obliquity problem. Both linear perturbation analysis and direct numerical integration of the governing differential equations can be used to obtain an obliquity time series, once a model value is selected for the moment of inertia
Directory of Open Access Journals (Sweden)
José E. O. Reges
2016-07-01
Full Text Available 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.
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
Haeseler, Friedrich
2003-01-01
Automatic sequences are sequences which are produced by a finite automaton. Although they are not random they may look as being random. They are complicated, in the sense of not being not ultimately periodic, they may look rather complicated, in the sense that it may not be easy to name the rule by which the sequence is generated, however there exists a rule which generates the sequence. The concept automatic sequences has special applications in algebra, number theory, finite automata and formal languages, combinatorics on words. The text deals with different aspects of automatic sequences, in particular:· a general introduction to automatic sequences· the basic (combinatorial) properties of automatic sequences· the algebraic approach to automatic sequences· geometric objects related to automatic sequences.
Automatic registration of serial mammary gland sections
Energy Technology Data Exchange (ETDEWEB)
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.
International Nuclear Information System (INIS)
Full text: Image registration is one source of uncertainty in image guided radiotherapy. The performance of masked, soft-tissue, automatic image registration of the prostate between CT and CBCT images was measured and its relationship with reduced imaging dose investigated. An anthropomorphic pelvis phantom (CIRS) was CT scanned and used as a reference for lGRT. Seven CBCT scans were taken using the Elekta Synergy system with nominal imaging doses from I to 40 mGy. Rigid-body image registration was repeated 100 times with randomly selected start positions representing normal prostate set-up errors. Image registration used the 'Elekta Correlation Ratio' algorithm with CT data masked to the prostate + 5 mm isotropic margin. Residual error analysis was performed to determine the registration accuracy, precision and robustness. Rigid body errors were analysed as target registration error (TRE), the average error between any two corresponding points on the surface of a 5 cm sphere centred on the isocentre. Similar methods were applied to 21 CBCT scans from seven patients. The TRE was stable for imaging doses above 6 mGy. Median(TRE) was 3.6 mm) was ation performance for patient images was highly variable; 4121 CT-CBCT registrations showed median(TRE) < I mm and RFF <20%. For the rest, median(TRE) was up to 9 mm and RFF from 20 to 90%. A clear dose response relationship was evident for CTCBCT image registration performance of the prostate in phantom measurements. Performance with patient images was highly variable.
Reorientation of Asymmetric Rigid Body Using Two Controls
Directory of Open Access Journals (Sweden)
Donghoon Kim
2013-01-01
Full Text Available Most spacecrafts are designed to be maneuvered to achieve pointing goals. This is accomplished usually by designing a three-axis control system, which can achieve arbitrary maneuvers, where the goal is to repoint the spacecraft and match a desired angular velocity at the end of the maneuver. New control laws are required, however, if one of the three-axis control actuators fails. This paper explores suboptimal maneuver strategies when only two control torque inputs are available. To handle this underactuated system control problem, the three-axis maneuver strategy is transformed to two successive independent submaneuver strategies. The first maneuver is conducted on one of the available torque axes. Next, the second maneuver is conducted on the torque available plane using two available control torques. However, the resulting control law is more complicated than the general three-axis control law. This is because an optimal switch time needs to be found for determining the end time for the single-axis maneuver or the start time for the second maneuver. Numerical simulation results are presented that compare optimal maneuver strategies for both nominal and failed actuator cases.
Reorientation of Asymmetric Rigid Body Using Two Controls
Donghoon Kim; Turner, James D.; Henzeh Leeghim
2013-01-01
Most spacecrafts are designed to be maneuvered to achieve pointing goals. This is accomplished usually by designing a three-axis control system, which can achieve arbitrary maneuvers, where the goal is to repoint the spacecraft and match a desired angular velocity at the end of the maneuver. New control laws are required, however, if one of the three-axis control actuators fails. This paper explores suboptimal maneuver strategies when only two control torque inputs are available. To handle th...
Reduced Order Aeroservoelastic Models with Rigid Body Modes Project
National Aeronautics and Space Administration — Complex aeroelastic and aeroservoelastic phenomena can be modeled on complete aircraft configurations generating models with millions of degrees of freedom....
Rigid-body molecular dynamics of DNA inside a nucleosome.
Fathizadeh, Arman; Berdy Besya, Azim; Reza Ejtehadi, Mohammad; Schiessel, Helmut
2013-03-01
The majority of eukaryotic DNA, about three quarter, is wrapped around histone proteins forming so-called nucleosomes. To study nucleosomal DNA we introduce a coarse-grained molecular dynamics model based on sequence-dependent harmonic rigid base pair step parameters of DNA and nucleosomal binding sites. Mixed parametrization based on all-atom molecular dynamics and crystallographic data of protein-DNA structures is used for the base pair step parameters. The binding site parameters are adjusted by experimental B-factor values of the nucleosome crystal structure. The model is then used to determine the energy cost for placing a twist defect into the nucleosomal DNA which allows us to use Kramers theory to calculate nucleosome sliding caused by such defects. It is shown that the twist defect scenario together with the sequence-dependent elasticity of DNA can explain the slow time scales observed for nucleosome mobility along DNA. With this method we also show how the twist defect mechanism leads to a higher mobility of DNA in the presence of sin mutations near the dyad axis. Finally, by performing simulations on 5s rDNA, 601, and telomeric base pair sequences, it is demonstrated that the current model is a powerful tool to predict nucleosome positioning. PMID:23475204
Hamiltonian Dynamics of Spider-Type Multirotor Rigid Bodies Systems
International Nuclear Information System (INIS)
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.
Control of fluid-containing rotating rigid bodies
Gurchenkov, Anatoly A
2013-01-01
This book is devoted to the study of the dynamics of rotating bodies with cavities containing liquid. Two basic classes of motions are analyzed: rotation and libration. Cases of complete and partial filling of cavities with ideal liquid and complete filling with viscous liquid are treated. The volume presents a method for obtaining relations between angular velocities perpendicular to main rotation and external force momentums, which are treated as control. The developed models and methods of solving dynamical problems as well as numerical methods for solving problems of optimal control can be
Dynamic model for landsliding monitoring under rigid body assumption
Institute of Scientific and Technical Information of China (English)
朱建军; 丁晓利; 陈永奇
2001-01-01
Based on the assumption that the slope bodies are rigid, the dynamic model of the landsiding (forward model) was put forward. According to the dynamic model, the system equations of Kalman filter were constituted. The mechanical status of a slope was hence combined with the monitoring data by Kalman filter. The model uncertainties or model errors could also be considered through some fictitious observation equations. Different from existed methods, the presented method can make use for not only the statistic information contained in the data but also the information provided by the mechanical and geological aspect of slopes. At last a numerical example was given out to show the feasibility of the method.
Simulation Methods in the Contact with Impact of Rigid Bodies
Directory of Open Access Journals (Sweden)
Cristina Basarabă-Opritescu
2007-10-01
Full Text Available The analysis of impacts of elastic bodies is topical and it has many applications, practical and theoretical, too. The elastic character of collision is put in evidence, especially by the velocities of some parts of a particular body, named “ring”. In the presented paper, the situation of elastic collisions is put in evidence by the simulation with the help of the program ANSYS and it refers to the particular case of the ring, with the mechanical characteristics, given in the paper
Dynamics of Rigid Bodies and Flexible Beam Structures
Nielsen, Martin Bjerre; Krenk, Steen
2013-01-01
Roterende bevægelse er et ofte forekommende fænomen indenfor mange ingeniørmæssige anvendelser såsom biler, roterende maskineri og vindmøllerotorer. Denne afhandling består af fire dele, der alle omhandler udvikling af effektive beregningsmetoder til modellering af den dynamiske opførsel af stive legemer og fleksible bjælkekonstruktioner med hovedvægt på den roterende bevægelse. Den første del vedrører bevægelse i en roterende referenceramme. En ny fremgangsmåde, hvor bevægelsesligningerne er...
A generic detailed rigid-body lumbar spine model
DEFF Research Database (Denmark)
De Zee, Mark; Hansen, Lone; Wong, Christian;
2007-01-01
The objective of this work is to present a musculo-skeletal model of the lumbar spine, which can be shared and lends itself to investigation in many locations by different researchers. This has the potential for greater reproducibility and subsequent improvement of its quality from the combined e...
Rigid body dynamics simulation for robot motion planning
Ettlin, Alan
2006-01-01
The development of robot motion planning algorithms is inherently a challenging task. This is more than ever true when the latest trends in motion planning are considered. Some motion planners can deal with kinematic and dynamic constraints induced by the mechanical structure of the robot. Another class of motion planners fulfill various types of optimality conditions, yet others include means of dealing with uncertainty about the robot and its environment. Sensor-based motion planners gather...
Dynamics of parallel robots from rigid bodies to flexible elements
Briot, Sébastien
2015-01-01
This book starts with a short recapitulation on basic concepts, common to any types of robots (serial, tree structure, parallel, etc.), that are also necessary for computation of the dynamic models of parallel robots. Then, as dynamics requires the use of geometry and kinematics, the general equations of geometric and kinematic models of parallel robots are given. After, it is explained that parallel robot dynamic models can be obtained by decomposing the real robot into two virtual systems: a tree-structure robot (equivalent to the robot legs for which all joints would be actuated) plus a free body corresponding to the platform. Thus, the dynamics of rigid tree-structure robots is analyzed and algorithms to obtain their dynamic models in the most compact form are given. The dynamic model of the real rigid parallel robot is obtained by closing the loops through the use of the Lagrange multipliers. The problem of the dynamic model degeneracy near singularities is treated and optimal trajectory planning for cro...
Collisions of rigid bodies, deformable bodies and fluids
DIMNET, E; Fremond, M.; GORMAZ, R; San Martin, J.
2003-01-01
The system made of two solids is deformable because the relative position of the solids may change. This idea is applied to an old and complex problem of mechanics : the collision theory. The major findings are constitutive laws which are coherent from the thermodynamics point of view. They give robust and productive models and numerical methods, for instance for rocks avalanches and collisions of solids and flluids.
Quaternion Feedback Control for Rigid-body Spacecraft
Jensen, Hans-Christian Becker; Wisniewski, Rafal
2001-01-01
This paper addresses three-axis attitude control for a Danish spacecraft, Roemer. The algorithm proposed is based on an approximation of the exact feedback linearisation for quaternionic attitude representation. The proposed attitude controller is tested in a simulation study. The environmental disturbances correspond to those expected for the Roemer mission. The pros and cons of the algorithm are discussed. The results of the study show that the controller is a > successful candidate for ...
Hurricane Balls: A rigid-body-motion student project
Jackson, David; Mertens, David; Pearson, Brett
Hurricane Balls is a spinning-top toy that consists of two metal spheres that are welded (or glued) together. The motion of Hurricane Balls provides a beautiful example of rotational motion in which the angular velocity and angular momentum point in different directions. Because the motion is both captivating to students and extremely reproducible, this system is an ideal example to include in a classical mechanics course. Moreover, the excellent agreement between theory and experiment makes a detailed analysis of Hurricane Balls a perfect topic for an independent student project. This talk will give an overview of the system and will provide some tips on how to make such a project a successful student experience.
Dynamics of Rigid Bodies and Flexible Beam Structures
DEFF Research Database (Denmark)
Nielsen, Martin Bjerre
quaternion parameters or nine convected base vector components. In both cases, the equations of motion are obtained via Hamilton’s equations by including the kinematic constraints associated with the redundant rotation description by means of Lagrange multipliers. A special feature of the formulation is that...
Quaternion Feedback Control for Rigid-body Spacecraft
DEFF Research Database (Denmark)
Jensen, Hans-Christian Becker; Wisniewski, Rafal
2001-01-01
This paper addresses three-axis attitude control for a Danish spacecraft, Roemer. The algorithm proposed is based on an approximation of the exact feedback linearisation for quaternionic attitude representation. The proposed attitude controller is tested in a simulation study. The environmental...
Reduced Order Aeroservoelastic Models with Rigid Body Modes Project
National Aeronautics and Space Administration — Complex aeroelastic and aeroservoelastic phenomena can be modeled on complete aircraft configurations, generating models with millions of degrees of freedom....
Euler-Poincaré Reduction of a Rigid Body Motion
DEFF Research Database (Denmark)
Wisniewski, Rafal; Kulczycki, P.
2004-01-01
If a mechanical system experiences symmetry, the Lagrangian becomes invariant under a certain group action. This property leads to substantial simplification of the description of movement. The standpoint in this article is a mechanical system affected by an external force of a control action. As...
International Nuclear Information System (INIS)
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
Long, Fan; Ganesh, Vijay; Carbin, Michael James; Sidiroglou, Stelios; Rinard, Martin
2012-01-01
We present a novel technique, automatic input rectification, and a prototype implementation, SOAP. SOAP learns a set of constraints characterizing typical inputs that an application is highly likely to process correctly. When given an atypical input that does not satisfy these constraints, SOAP automatically rectifies the input (i.e., changes the input so that it satisfies the learned constraints). The goal is to automatically convert potentially dangerous inputs into typical inputs that the ...
Directory of Open Access Journals (Sweden)
Narcis Eduard Mitu
2013-11-01
Full Text Available Policies or institutions (built into an economic system that automatically tend to dampen economic cycle fluctuations in income, employment, etc., without direct government intervention. For example, in boom times, progressive income tax automatically reduces money supply as incomes and spendings rise. Similarly, in recessionary times, payment of unemployment benefits injects more money in the system and stimulates demand. Also called automatic stabilizers or built-in stabilizers.
Automatic differentiation bibliography
Energy Technology Data Exchange (ETDEWEB)
Corliss, G.F. (comp.)
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.
Automatic Implantable Cardiac Defibrillator
Full Text Available Automatic Implantable Cardiac Defibrillator February 19, 2009 Halifax Health Medical Center, Daytona Beach, FL Welcome to Halifax Health Daytona Beach, Florida. Over the next hour you' ...
Automatic Payroll Deposit System.
Davidson, D. B.
1979-01-01
The Automatic Payroll Deposit System in Yakima, Washington's Public School District No. 7, directly transmits each employee's salary amount for each pay period to a bank or other financial institution. (Author/MLF)
Directory of Open Access Journals (Sweden)
Leandro Martínez
Full Text Available 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.
A review of metaphase chromosome image selection techniques for automatic karyotype generation.
Arora, Tanvi; Dhir, Renu
2016-08-01
The karyotype is analyzed to detect the genetic abnormalities. It is generated by arranging the chromosomes after extracting them from the metaphase chromosome images. The chromosomes are non-rigid bodies that contain the genetic information of an individual. The metaphase chromosome image spread contains the chromosomes, but these chromosomes are not distinct bodies; they can either be individual chromosomes or be touching one another; they may be bent or even may be overlapping and thus forming a cluster of chromosomes. The extraction of chromosomes from these touching and overlapping chromosomes is a very tedious process. The segmentation of a random metaphase chromosome image may not give us correct and accurate results. Therefore, before taking up a metaphase chromosome image for analysis, it must be analyzed for the orientation of the chromosomes it contains. The various reported methods for metaphase chromosome image selection for automatic karyotype generation are compared in this paper. After analysis, it has been concluded that each metaphase chromosome image selection method has its advantages and disadvantages. PMID:26676686
Automatic Arabic Text Classification
Al-harbi, S; Almuhareb, A.; Al-Thubaity , A; Khorsheed, M. S.; Al-Rajeh, A.
2008-01-01
Automated document classification is an important text mining task especially with the rapid growth of the number of online documents present in Arabic language. Text classification aims to automatically assign the text to a predefined category based on linguistic features. Such a process has different useful applications including, but not restricted to, e-mail spam detection, web page content filtering, and automatic message routing. This paper presents the results of experiments on documen...
DEFF Research Database (Denmark)
Automatic Program Development is a tribute to Robert Paige (1947-1999), our accomplished and respected colleague, and moreover our good friend, whose untimely passing was a loss to our academic and research community. We have collected the revised, updated versions of the papers published in his...... honor in the Higher-Order and Symbolic Computation Journal in the years 2003 and 2005. Among them there are two papers by Bob: (i) a retrospective view of his research lines, and (ii) a proposal for future studies in the area of the automatic program derivation. The book also includes some papers by...... members of the IFIP Working Group 2.1 of which Bob was an active member. All papers are related to some of the research interests of Bob and, in particular, to the transformational development of programs and their algorithmic derivation from formal specifications. Automatic Program Development offers a...
Energy Technology Data Exchange (ETDEWEB)
Smith, Colin Boughton [Energy Metering Technology (United Kingdom)
2000-08-01
At present, energy audits represent only snapshot situations of the flow of energy. The normal pattern of energy audits as seen through the eyes of an experienced energy auditor is described. A brief history of energy auditing is given. It is claimed that the future of energy auditing lies in automatic meter reading with expert data analysis providing continuous automatic auditing thereby reducing the skill element. Ultimately, it will be feasible to carry out auditing at intervals of say 30 minutes rather than five years.
DEFF Research Database (Denmark)
Burelli, Paolo; Preuss, Mike
2014-01-01
Automatically generating computer animations is a challenging and complex problem with applications in games and film production. In this paper, we investigate howto translate a shot list for a virtual scene into a series of virtual camera configurations — i.e automatically controlling the virtual...... camera. We approach this problem by modelling it as a dynamic multi-objective optimisation problem and show how this metaphor allows a much richer expressiveness than a classical single objective approach. Finally, we showcase the application of a multi-objective evolutionary algorithm to generate a shot...
Torres Moreno, Juan Manuel
2014-01-01
This new textbook examines the motivations and the different algorithms for automatic document summarization (ADS). We performed a recent state of the art. The book shows the main problems of ADS, difficulties and the solutions provided by the community. It presents recent advances in ADS, as well as current applications and trends. The approaches are statistical, linguistic and symbolic. Several exemples are included in order to clarify the theoretical concepts. The books currently available in the area of Automatic Document Summarization are not recent. Powerful algorithms have been develop
Automatic Dance Lesson Generation
Yang, Yang; Leung, H.; Yue, Lihua; Deng, LiQun
2012-01-01
In this paper, an automatic lesson generation system is presented which is suitable in a learning-by-mimicking scenario where the learning objects can be represented as multiattribute time series data. The dance is used as an example in this paper to illustrate the idea. Given a dance motion sequence as the input, the proposed lesson generation…
DEFF Research Database (Denmark)
Rosendahl, Mads
1989-01-01
One way to analyse programs is to to derive expressions for their computational behaviour. A time bound function (or worst-case complexity) gives an upper bound for the computation time as a function of the size of input. We describe a system to derive such time bounds automatically using abstract...
Automatic indexing, compiling and classification
International Nuclear Information System (INIS)
A review of the principles of automatic indexing, is followed by a comparison and summing-up of work by the authors and by a Soviet staff from the Moscou INFORM-ELECTRO Institute. The mathematical and linguistic problems of the automatic building of thesaurus and automatic classification are examined
International Nuclear Information System (INIS)
The paper describes the automatic gaussmeter operating according to the principle of nuclear magnetic resonance. There have been discussed the operating principle, the block diagram and operating parameters of the meter. It can be applied to measurements of induction in electromagnets of wide-line radio-spectrometers EPR and NMR and in calibration stands of magnetic induction values. Frequency range of an autodyne oscillator from 0,6 up to 86 MHz for protons is corresponding to the field range from 0.016 up to 2T. Applicaton of other nuclei, such as 7Li and 2D is also foreseen. The induction measurement is carried over automatically, and the NMR signal and value of measured induction are displayed on a monitor screen. (author)
Vamos¸, C˘alin
2013-01-01
Our book introduces a method to evaluate the accuracy of trend estimation algorithms under conditions similar to those encountered in real time series processing. This method is based on Monte Carlo experiments with artificial time series numerically generated by an original algorithm. The second part of the book contains several automatic algorithms for trend estimation and time series partitioning. The source codes of the computer programs implementing these original automatic algorithms are given in the appendix and will be freely available on the web. The book contains clear statement of the conditions and the approximations under which the algorithms work, as well as the proper interpretation of their results. We illustrate the functioning of the analyzed algorithms by processing time series from astrophysics, finance, biophysics, and paleoclimatology. The numerical experiment method extensively used in our book is already in common use in computational and statistical physics.
P.KEERTHANAA, K.JEEVITHA, V.NAVINA, G.INDIRA, S.JAYAMANI
2013-01-01
The Primary Aim Of The Project Is To Design, Develop And Implement Automatic Wall Painting Robot Which Helps To Achieve Low Cost Painting Equipment. Despite The Advances In Robotics And Its Wide Spreading Applications, Interior Wall Painting Has Shared Little In Research Activities. The Painting Chemicals Can Cause Hazards To The Human Painters Such As Eye And Respiratory System Problems. Also The Nature Of Painting Procedure That Requires Repeated Work And Hand Rising Makes It Boring, Time A...
Lígia Maria da Silva Ribeiro; Gabriel de Sousa Torcato David
2007-01-01
To profit from the data collected by the SIGARRA academic IS, a systematic setof graphs and statistics has been added to it and are available on-line. Thisanalytic information can be automatically included in a flexible yearly report foreach program as well as in a synthesis report for the whole school. Somedifficulties in the interpretation of some graphs led to the definition of new keyindicators and the development of a data warehouse across the university whereeffective data consolidation...
Automatic Inductive Programming Tutorial
Aler, Ricardo
2006-01-01
Computers that can program themselves is an old dream of Artificial Intelligence, but only nowadays there is some progress of remark. In relation to Machine Learning, a computer program is the most powerful structure that can be learned, pushing the final goal well beyond neural networks or decision trees. There are currently many separate areas, working independently, related to automatic programming, both deductive and inductive. The first goal of this tutorial is to give to the attendants ...
DEFF Research Database (Denmark)
Mueller Loose, Simone
Consumers' food decisions are to a large extent shaped by automatic processes, which are either internally directed through learned habits and routines or externally influenced by context factors and visual information triggers. Innovative research methods such as eye tracking, choice experiments...... and food diaries allow us to better understand the impact of unconscious processes on consumers' food choices. Simone Mueller Loose will provide an overview of recent research insights into the effects of habit and context on consumers' food choices....
Automatic Differentiation Variational Inference
Kucukelbir, Alp; Tran, Dustin; Ranganath, Rajesh; Gelman, Andrew; Blei, David M.
2016-01-01
Probabilistic modeling is iterative. A scientist posits a simple model, fits it to her data, refines it according to her analysis, and repeats. However, fitting complex models to large data is a bottleneck in this process. Deriving algorithms for new models can be both mathematically and computationally challenging, which makes it difficult to efficiently cycle through the steps. To this end, we develop automatic differentiation variational inference (ADVI). Using our method, the scientist on...
Automaticity or active control
DEFF Research Database (Denmark)
Tudoran, Ana Alina; Olsen, Svein Ottar
This study addresses the quasi-moderating role of habit strength in explaining action loyalty. A model of loyalty behaviour is proposed that extends the traditional satisfaction–intention–action loyalty network. Habit strength is conceptualised as a cognitive construct to refer to the psychologic......, respectively, between intended loyalty and action loyalty. At high levels of habit strength, consumers are more likely to free up cognitive resources and incline the balance from controlled to routine and automatic-like responses....
Automatic digital image registration
Goshtasby, A.; Jain, A. K.; Enslin, W. R.
1982-01-01
This paper introduces a general procedure for automatic registration of two images which may have translational, rotational, and scaling differences. This procedure involves (1) segmentation of the images, (2) isolation of dominant objects from the images, (3) determination of corresponding objects in the two images, and (4) estimation of transformation parameters using the center of gravities of objects as control points. An example is given which uses this technique to register two images which have translational, rotational, and scaling differences.
Automatic radioactive waste recycling
International Nuclear Information System (INIS)
The production of a plutonium ingot by calcium reduction process at CEA/Valduc generates a residue called 'slag'. This article introduces the recycling unit which is dedicated to the treatment of slags. The aim is to separate and to recycle the plutonium trapped in this bulk on the one hand, and to generate a disposable waste from the slag on the other hand. After a general introduction of the facilities, some elements will be enlightened, particularly the dissolution step, the filtration and the drying equipment. Reflections upon technological constraints will be proposed, and the benefits of a fully automatic recycling unit of nuclear waste will also be stressed. (authors)
Automatic Configuration in NTP
Institute of Scientific and Technical Information of China (English)
Jiang Zongli(蒋宗礼); Xu Binbin
2003-01-01
NTP is nowadays the most widely used distributed network time protocol, which aims at synchronizing the clocks of computers in a network and keeping the accuracy and validation of the time information which is transmitted in the network. Without automatic configuration mechanism, the stability and flexibility of the synchronization network built upon NTP protocol are not satisfying. P2P's resource discovery mechanism is used to look for time sources in a synchronization network, and according to the network environment and node's quality, the synchronization network is constructed dynamically.
International Nuclear Information System (INIS)
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
Automatic personnel contamination monitor
International Nuclear Information System (INIS)
United Nuclear Industries, Inc. (UNI) has developed an automatic personnel contamination monitor (APCM), which uniquely combines the design features of both portal and hand and shoe monitors. In addition, this prototype system also has a number of new features, including: micro computer control and readout, nineteen large area gas flow detectors, real-time background compensation, self-checking for system failures, and card reader identification and control. UNI's experience in operating the Hanford N Reactor, located in Richland, Washington, has shown the necessity of automatically monitoring plant personnel for contamination after they have passed through the procedurally controlled radiation zones. This final check ensures that each radiation zone worker has been properly checked before leaving company controlled boundaries. Investigation of the commercially available portal and hand and shoe monitors indicated that they did not have the sensitivity or sophistication required for UNI's application, therefore, a development program was initiated, resulting in the subject monitor. Field testing shows good sensitivity to personnel contamination with the majority of alarms showing contaminants on clothing, face and head areas. In general, the APCM has sensitivity comparable to portal survey instrumentation. The inherit stand-in, walk-on feature of the APCM not only makes it easy to use, but makes it difficult to bypass. (author)
Automatic MR volume registration and its evaluation for the pelvis and prostate
International Nuclear Information System (INIS)
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± 0.2mm 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 can
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.
Automatic Speaker Recognition System
Directory of Open Access Journals (Sweden)
Parul,R. B. Dubey
2012-12-01
Full Text Available Spoken language is used by human to convey many types of information. Primarily, speech convey message via words. Owing to advanced speech technologies, people's interactions with remote machines, such as phone banking, internet browsing, and secured information retrieval by voice, is becoming popular today. Speaker verification and speaker identification are important for authentication and verification in security purpose. Speaker identification methods can be divided into text independent and text-dependent. Speaker recognition is the process of automatically recognizing speaker voice on the basis of individual information included in the input speech waves. It consists of comparing a speech signal from an unknown speaker to a set of stored data of known speakers. This process recognizes who has spoken by matching input signal with pre- stored samples. The work is focussed to improve the performance of the speaker verification under noisy conditions.
Directory of Open Access Journals (Sweden)
P.KEERTHANAA, K.JEEVITHA, V.NAVINA, G.INDIRA, S.JAYAMANI
2013-07-01
Full Text Available The Primary Aim Of The Project Is To Design, Develop And Implement Automatic Wall Painting Robot Which Helps To Achieve Low Cost Painting Equipment. Despite The Advances In Robotics And Its Wide Spreading Applications, Interior Wall Painting Has Shared Little In Research Activities. The Painting Chemicals Can Cause Hazards To The Human Painters Such As Eye And Respiratory System Problems. Also The Nature Of Painting Procedure That Requires Repeated Work And Hand Rising Makes It Boring, Time And Effort Consuming. When Construction Workers And Robots Are Properly Integrated In Building Tasks, The Whole Construction Process Can Be Better Managed And Savings In Human Labour And Timing Are Obtained As A Consequence. In Addition, It Would Offer The Opportunity To Reduce Or Eliminate Human Exposure To Difficult And Hazardous Environments, Which Would Solve Most Of The Problems Connected With Safety When Many Activities Occur At The Same Time. These Factors Motivate The Development Of An Automated Robotic Painting System.
Automatic alkaloid removal system.
Yahaya, Muhammad Rizuwan; Hj Razali, Mohd Hudzari; Abu Bakar, Che Abdullah; Ismail, Wan Ishak Wan; Muda, Wan Musa Wan; Mat, Nashriyah; Zakaria, Abd
2014-01-01
This alkaloid automated removal machine was developed at Instrumentation Laboratory, Universiti Sultan Zainal Abidin Malaysia that purposely for removing the alkaloid toxicity from Dioscorea hispida (DH) tuber. It is a poisonous plant where scientific study has shown that its tubers contain toxic alkaloid constituents, dioscorine. The tubers can only be consumed after it poisonous is removed. In this experiment, the tubers are needed to blend as powder form before inserting into machine basket. The user is need to push the START button on machine controller for switching the water pump ON by then creating turbulence wave of water in machine tank. The water will stop automatically by triggering the outlet solenoid valve. The powders of tubers are washed for 10 minutes while 1 liter of contaminated water due toxin mixture is flowing out. At this time, the controller will automatically triggered inlet solenoid valve and the new water will flow in machine tank until achieve the desire level that which determined by ultra sonic sensor. This process will repeated for 7 h and the positive result is achieved and shows it significant according to the several parameters of biological character ofpH, temperature, dissolve oxygen, turbidity, conductivity and fish survival rate or time. From that parameter, it also shows the positive result which is near or same with control water and assuming was made that the toxin is fully removed when the pH of DH powder is near with control water. For control water, the pH is about 5.3 while water from this experiment process is 6.0 and before run the machine the pH of contaminated water is about 3.8 which are too acid. This automated machine can save time for removing toxicity from DH compared with a traditional method while less observation of the user. PMID:24783795
Making automatic differentiation truly automatic : coupling PETSc with ADIC
International Nuclear Information System (INIS)
Despite its name, automatic differentiation (AD) is often far from an automatic process. often one must specify independent and dependent variables, indicate the derivative quantities to be computed, and perhaps even provide information about the structure of the Jacobians or Hessians being computed. However, when AD is used in conjunction with a toolkit with well-defined interfaces, many of these issues do not arise. They describe recent research into coupling the ADIC automatic differentiation tool with PETSc, a toolkit for the parallel numerical solution of PDEs. This research leverages the interfaces and objects of PETSc to make the AD process very nearly transparent
Automatic Kurdish Dialects Identification
Directory of Open Access Journals (Sweden)
Hossein Hassani
2016-02-01
Full Text Available Automatic dialect identification is a necessary Lan guage Technology for processing multi- dialect languages in which the dialects are linguis tically far from each other. Particularly, this becomes crucial where the dialects are mutually uni ntelligible. Therefore, to perform computational activities on these languages, the sy stem needs to identify the dialect that is the subject of the process. Kurdish language encompasse s various dialects. It is written using several different scripts. The language lacks of a standard orthography. This situation makes the Kurdish dialectal identification more interesti ng and required, both form the research and from the application perspectives. In this research , we have applied a classification method, based on supervised machine learning, to identify t he dialects of the Kurdish texts. The research has focused on two widely spoken and most dominant Kurdish dialects, namely, Kurmanji and Sorani. The approach could be applied to the other Kurdish dialects as well. The method is also applicable to the languages which are similar to Ku rdish in their dialectal diversity and differences.
Electronic amplifiers for automatic compensators
Polonnikov, D Ye
1965-01-01
Electronic Amplifiers for Automatic Compensators presents the design and operation of electronic amplifiers for use in automatic control and measuring systems. This book is composed of eight chapters that consider the problems of constructing input and output circuits of amplifiers, suppression of interference and ensuring high sensitivity.This work begins with a survey of the operating principles of electronic amplifiers in automatic compensator systems. The succeeding chapters deal with circuit selection and the calculation and determination of the principal characteristics of amplifiers, as
Clothes Dryer Automatic Termination Evaluation
Energy Technology Data Exchange (ETDEWEB)
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.
Prospects for de-automatization.
Kihlstrom, John F
2011-06-01
Research by Raz and his associates has repeatedly found that suggestions for hypnotic agnosia, administered to highly hypnotizable subjects, reduce or even eliminate Stroop interference. The present paper sought unsuccessfully to extend these findings to negative priming in the Stroop task. Nevertheless, the reduction of Stroop interference has broad theoretical implications, both for our understanding of automaticity and for the prospect of de-automatizing cognition in meditation and other altered states of consciousness. PMID:20356765
Process automatization in system administration
Petauer, Janja
2013-01-01
The aim of the thesis is to present automatization of user management in company Studio Moderna. The company has grown exponentially in recent years, that is why we needed to find faster, easier and cheaper way of man- aging user accounts. We automatized processes of creating, changing and removing user accounts within Active Directory. We prepared user interface inside of existing application, used Java Script for drop down menus, wrote script in scripting programming langu...
Automatic Number Plate Recognition System
Rajshree Dhruw; Dharmendra Roy
2014-01-01
Automatic Number Plate Recognition (ANPR) is a mass surveillance system that captures the image of vehicles and recognizes their license number. The objective is to design an efficient automatic authorized vehicle identification system by using the Indian vehicle number plate. In this paper we discus different methodology for number plate localization, character segmentation & recognition of the number plate. The system is mainly applicable for non standard Indian number plates by recognizing...
Eating as an Automatic Behavior
Deborah A. Cohen, MD, MPH; Thomas A. Farley, MD, MPH
2007-01-01
The continued growth of the obesity epidemic at a time when obesity is highly stigmatizing should make us question the assumption that, given the right information and motivation, people can successfully reduce their food intake over the long term. An alternative view is that eating is an automatic behavior over which the environment has more control than do individuals. Automatic behaviors are those that occur without awareness, are initiated without intention, tend to continue without contr...
Annual review in automatic programming
Goodman, Richard
2014-01-01
Annual Review in Automatic Programming focuses on the techniques of automatic programming used with digital computers. Topics covered range from the design of machine-independent programming languages to the use of recursive procedures in ALGOL 60. A multi-pass translation scheme for ALGOL 60 is described, along with some commercial source languages. The structure and use of the syntax-directed compiler is also considered.Comprised of 12 chapters, this volume begins with a discussion on the basic ideas involved in the description of a computing process as a program for a computer, expressed in
Automatic Radiation Monitoring in Slovenia
International Nuclear Information System (INIS)
Full text: The automatic radiation monitoring system in Slovenia started in early nineties and now it comprises measurements of: 1. External gamma radiation: For the time being there are forty-three probes with GM tubes integrated into a common automatic network, operated at the SNSA. The probes measure dose rate in 30 minute intervals. 2. Aerosol radioactivity: Three automatic aerosol stations measure the concentration of artificial alpha and beta activity in the air, gamma emitting radionuclides, radioactive iodine 131 in the air (in all chemical forms, - natural radon and thoron progeny, 3. Radon progeny concentration: Radon progeny concentration is measured hourly and results are displayed as the equilibrium equivalent concentrations (EEC), 4. Radioactive deposition measurements: As a support to gamma dose rate measurements - the SNSA developed and installed an automatic measuring station for surface contamination equipped with gamma spectrometry system (with 3x3' NaI(Tl) detector). All data are transferred through the different communication pathways to the SNSA. They are collected in 30 minute intervals. Within these intervals the central computer analyses and processes the collected data, and creates different reports. Every month QA/QC analysis of data is performed, showing the statistics of acquisition errors and availability of measuring results. All results are promptly available at the our WEB pages. The data are checked and daily sent to the EURDEP system at Ispra (Italy) and also to the Austrian, Croatian and Hungarian authorities. (author)
Eating as an Automatic Behavior
Directory of Open Access Journals (Sweden)
Deborah A. Cohen, MD, MPH
2008-01-01
Full Text Available The continued growth of the obesity epidemic at a time when obesity is highly stigmatizing should make us question the assumption that, given the right information and motivation, people can successfully reduce their food intake over the long term. An alternative view is that eating is an automatic behavior over which the environment has more control than do individuals. Automatic behaviors are those that occur without awareness, are initiated without intention, tend to continue without control, and operate efficiently or with little effort. The concept that eating is an automatic behavior is supported by studies that demonstrate the impact of the environmental context and food presentation on eating. The amount of food eaten is strongly influenced by factors such as portion size, food visibility and salience, and the ease of obtaining food. Moreover, people are often unaware of the amount of food they have eaten or of the environmental influences on their eating. A revised view of eating as an automatic behavior, as opposed to one that humans can self-regulate, has profound implications for our response to the obesity epidemic, suggesting that the focus should be less on nutrition education and more on shaping the food environment.
Automatic Association of News Items.
Carrick, Christina; Watters, Carolyn
1997-01-01
Discussion of electronic news delivery systems and the automatic generation of electronic editions focuses on the association of related items of different media type, specifically photos and stories. The goal is to be able to determine to what degree any two news items refer to the same news event. (Author/LRW)
Automatic quantification of iris color
DEFF Research Database (Denmark)
Christoffersen, S.; Harder, Stine; Andersen, J. D.;
2012-01-01
An automatic algorithm to quantify the eye colour and structural information from standard hi-resolution photos of the human iris has been developed. Initially, the major structures in the eye region are identified including the pupil, iris, sclera, and eyelashes. Based on this segmentation, the ...
05501 Summary -- Automatic Performance Analysis
Gerndt, Hans Michael; Malony, Allen; Miller, Barton P.; Nagel, Wolfgang
2006-01-01
The Workshop on Automatic Performance Analysis (WAPA 2005, Dagstuhl Seminar 05501), held December 13-16, 2005, brought together performance researchers, developers, and practitioners with the goal of better understanding the methods, techniques, and tools that are needed for the automation of performance analysis for high performance computing.
Automatic Identification of Metaphoric Utterances
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…
On the steady fall of a rigid body in oseen flox-weighted approach
Czech Academy of Sciences Publication Activity Database
Kračmar, S.; Nečasová, Šárka
2006-01-01
Roč. 1, č. 1 (2006), s. 83-88. ISSN 1790-5087 R&D Projects: GA AV ČR(CZ) IAA100190506 Institutional research plan: CEZ:AV0Z10190503 Keywords : steady fall * Oseen flox * weighted spaces Subject RIV: BA - General Mathematics
Quantitative Validation of a Human Body Finite Element Model Using Rigid Body Impacts.
Vavalle, Nicholas A; Davis, Matthew L; Stitzel, Joel D; Gayzik, F Scott
2015-09-01
Validation is a critical step in finite element model (FEM) development. This study focuses on the validation of the Global Human Body Models Consortium full body average male occupant FEM in five localized loading regimes-a chest impact, a shoulder impact, a thoracoabdominal impact, an abdominal impact, and a pelvic impact. Force and deflection outputs from the model were compared to experimental traces and corridors scaled to the 50th percentile male. Predicted fractures and injury severity measures were compared to evaluate the model's injury prediction capabilities. The methods of ISO/TS 18571 were used to quantitatively assess the fit of model outputs to experimental force and deflection traces. The model produced peak chest, shoulder, thoracoabdominal, abdominal, and pelvis forces of 4.8, 3.3, 4.5, 5.1, and 13.0 kN compared to 4.3, 3.2, 4.0, 4.0, and 10.3 kN in the experiments, respectively. The model predicted rib and pelvic fractures related to Abbreviated Injury Scale scores within the ranges found experimentally all cases except the abdominal impact. ISO/TS 18571 scores for the impacts studied had a mean score of 0.73 with a range of 0.57-0.83. Well-validated FEMs are important tools used by engineers in advancing occupant safety. PMID:25739950
Asymmetric steady streaming as a mechanism for acoustic propulsion of rigid bodies
Nadal, Francois
2014-01-01
Recent experiments showed that standing acoustic waves could be exploited to induce self-propulsion of rigid metallic particles in the direction perpendicular to the acoustic wave. We propose in this paper a physical mechanism for these observations based on the interplay between inertial forces in the fluid and the geometrical asymmetry of the particle shape. We consider an axisymmetric rigid near-sphere oscillating in a quiescent fluid along a direction perpendicular to its symmetry axis. The kinematics of oscillations can be either prescribed or can result dynamically from the presence of an external oscillating velocity field. Steady streaming in the fluid, the inertial rectification of the time-periodic oscillating flow, generates steady stresses on the particle which, in general, do not average to zero, resulting in a finite propulsion speed along the axis of the symmetry of the particle and perpendicular to the oscillation direction. Our derivation of the propulsion speed is obtained at leading order i...
Beyond Rigid Body: Integrated Structural Control of Extremely Lightweight Flexible Aircraft
Bosworth, John T.
2013-01-01
Integrated structural control of extremely lightweight vehicles will open a new paradigm and allow for performance increases. The X-56A Multi-Utility Technology Testbed (MUTT) vehicle will be used to evaluate and advance the state-of-the-art in modeling and control of this new class of aerospace vehicle.
Coupling between eddy currents and rigid body rotation: analysis, computation, and experiments
International Nuclear Information System (INIS)
Computation and experiment show that the coupling between eddy currents and the angular deflections resulting from those eddy currents can reduce electromagnetic effects such as forces, torques, and power dissipation to levels far less severe than would be predicted without regard for the coupling. This paper explores the coupling effects beyond the parameter range that has been explored experimentally, using analytical means and the eddy-current computer code EDDYNET. The paper also describes upcoming FELIX experiments with cantilevered beams
Pseudo-Rigid-Body Model and Kinematic Analysis of MRI-Actuated Catheters
Greigarn, Tipakorn; Çavuşoğlu, M. Cenk
2015-01-01
This paper presents a kinematic study of a pseudorigid-body model (PRBM) of MRI-compatible, magnetically actuated, steerable catheters. It includes a derivation of a mathematical model of the PRBM of the catheter, singularity studies of the model, and a new manipulability measure. While the forward kinematics of the model presented here is applicable to PRBMs for other applications, actuation method is unique to the particular design. Hence, a careful study of singularities and manipulability of the model is required. The singularities are studied from the underlying equations of motion with intuitive interpretations. The proposed manipulability measure is a generalization of the inverse condition number manipulability measure of robotic manipulators. While the PRBM is an approximation of the flexible catheter, kinematic studies of the PRBM still provide some insight into feasibility and limitations of the catheter, which is beneficial to the design and motion planning of the catheter. PMID:26413380
The dynamics of a rigid body on an absolutely rough plane
Markeev, A. P.
1983-08-01
An attempt is made to explain certain dynamic effects associated with the rattleback, with particular emphasis placed on the oscillations of the body near the equilibrium position or near stationary rotation. The small oscillations of the body in the neighborhood of its stationary rotation about the vertical are analyzed; an approximate system of equations describing the nonlinear oscillations of the rattleback near its equilibrium position on a plane is derived; and a complete analysis of this system is given. The results agree with experimentally observed variations of the direction of the rotation of the body about the vertical in the absence of external influence and the appearance of rotation in both directions due to oscillations about the horizontal axis.
Geometry, Kinematics, and Rigid Body Mechanics in Cayley-Klein Geometries
Gunn, Charles
2011-01-01
Die vorliegende Arbeit präsentiert eine moderne Formulierung der Mechanik starrer Körper in Räumen konstanter Krümmung. Die Arbeit besteht aus einem theoretischen und einem praktischen Teil. Zunächst werden theoretische Grundlagen aus projektiver Geometrie, äußerer Algebra und quadratischen Formen vorgestellt, um darauf aufbauend eine Klasse von Cayley-Klein Räumen zu beschreiben. Diese Klasse enthält die drei klassischen Räume konstanter Krümmung (euklidisch, elliptisch und hyperbolisch). Di...
Efficient Lie-Poisson Integrator for Secular Spin Dynamics of Rigid Bodies
Breiter, Sławomir; Nesvorný, David; Vokrouhlický, David
2005-09-01
A fast and efficient numerical integration algorithm is presented for the problem of the secular evolution of the spin axis. Under the assumption that a celestial body rotates around its maximum moment of inertia, the equations of motion are reduced to the Hamiltonian form with a Lie-Poisson bracket. The integration method is based on the splitting of the Hamiltonian function, and so it conserves the Lie-Poisson structure. Two alternative partitions of the Hamiltonian are investigated, and second-order leapfrog integrators are provided for both cases. Non-Hamiltonian torques can be incorporated into the integrators with a combination of Euler and Lie-Euler approximations. Numerical tests of the methods confirm their useful properties of short computation time and reliability on long integration intervals.
On relative equilibria of mutually gravitating massive point and triangular rigid body
Nikonov, Vasily I.
2014-07-01
Planar motions of a triangular body and a massive point under the action of mutual Newtonian attraction are studied. For the first formulation the triangle is assumed to be composed of three massive points. For the second formulation it is constructed with three homogeneous rods. Some partial solutions are observed within the analysis of the geometry of mass distribution. The investigation is motivated by the problem of motion of spacecrafts near asteroid-like celestial objects possessing irregular mass distribution. Comparison of dynamical effects for two types of mass distribution is another goal of the research. Problems appearing because of irregularities in mass distributions have been known for a long time. Certain approaches to the description of motions under attraction as well as qualitative particulars of dynamics are discussed by Demin (1963), Burov & Karapetyan (1995), Buchin & Burov & Troger (2008), Burov & Guerman & Sulikashvili (2010), Kholshevnikov & Kuznetsov (2011), Beletsky & Rodnikov (2011) and Scheeres (2012).
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.
DEFF Research Database (Denmark)
Silcowitz, Morten; Niebe, Sarah Maria; Erleben, Kenny
2010-01-01
We present a novel, yet simple, method for stabilization of normal forces. A normal stabilization term, carefully designed from hypotheses about interactive usability, is added to the contact force problem. Further, we propose friction stabilization as a completely new stabilization paradigm in i...
Necessary conditions for partial controllability of a rigid body - gyrodyne system
International Nuclear Information System (INIS)
Controllability with respect to certain variables. We will examine dynamic systems that can be described by ordinary differential equations. Where x element-of D improper-subset Rn is the phase vector; u element-of U improper-subset Rm is the control vector. The latter is a bounded measureable function of time t, t element-of T = [0, ∞]. We assume that the regions D and U are convex and contain the coordinate origin. We also assume the function f to be a function of its arguments that is continuously differentiable a sufficient number of times. We divide the phase vector into two subvectors xT = (xαT, xβT) (xα element-of Dα improper-subset Rα, xβ element-of D improper-subset Rβ) and we introduce the following definition for system (1.1)
Quaternions in Hamiltonian dynamics of a rigid body -- Part III. Asymmetric Top in the Orbitron
Zub, Stanislav S
2015-01-01
The Poisson structure in the quaternion variables was proposed for asymmetric top in the external axially symmetric magnetic field. For that model of interaction the motion equation were got. The model was simulated in the neighbourhood of a relative equilibrium of the symmetric top -- Orbitron by Monte Carlo method. For small deviations with respect to the symmetry we observe the persistence of the stability.
Rationalizing foot and ankle measurements to conform to a rigid body model.
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. PMID:16880161
Unstructured finite volume method for water impact on a rigid body
Institute of Scientific and Technical Information of China (English)
YU Yan; MING Ping-jian; DUAN Wen-yang
2014-01-01
A new method is presented for the water impact simulation, in which the air-water two phase flow is solved using the pressure-based computational fluid dynamics method. Theoretically, the air effects can be taken into account in the water structure interaction. The key point of this method is the air-water interface capture, which is treated as a physical discontinuity and can be captured by a well-designed high order scheme. According to a normalized variable diagram, a high order discrete scheme on unstructured grids is realised, so a numerical method for the free surface flow on a fixed grid can be established. This method is implemented using an in-house code, the General Transport Equation Analyzer, which is an unstructured grid finite volume solver. The method is verified with the wedge water and structure interaction problem.
Robust methods for automatic image-to-world registration in cone-beam CT interventional guidance
International Nuclear Information System (INIS)
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 ∼200 mm of C-arm isocenter. Marker localization in projection data was robust across all
International Nuclear Information System (INIS)
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 deg. 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 deg. to 22 deg. 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
Orbital welding automatic pressure test by ODA automatic machines is 35 years old
International Nuclear Information System (INIS)
Development review of technology and equipment of automatic orbital welding with automatic pressures test of nuclear power stations pipelines and different purpose objects is performed. Welding variants with automatic pressure test and different welding automatic machines are described. Priority of national developments is underlined
Automatic mapping of monitoring data
DEFF Research Database (Denmark)
Lophaven, Søren; Nielsen, Hans Bruun; Søndergaard, Jacob
2005-01-01
This paper presents an approach, based on universal kriging, for automatic mapping of monitoring data. The performance of the mapping approach is tested on two data-sets containing daily mean gamma dose rates in Germany reported by means of the national automatic monitoring network (IMIS). In the...... second dataset an accidental release of radioactivity in the environment was simulated in the South-Western corner of the monitored area. The approach has a tendency to smooth the actual data values, and therefore it underestimates extreme values, as seen in the second dataset. However, it is capable of...... identifying a release of radioactivity provided that the number of sampling locations is sufficiently high. Consequently, we believe that a combination of applying the presented mapping approach and the physical knowledge of the transport processes of radioactivity should be used to predict the extreme values...
Automatic Schema Evolution in Root
Institute of Scientific and Technical Information of China (English)
ReneBrun; FonsRademakers
2001-01-01
ROOT version 3(spring 2001) supports automatic class schema evolution.In addition this version also produces files that are self-describing.This is achieved by storing in each file a record with the description of all the persistent classes in the file.Being self-describing guarantees that a file can always be read later,its structure browsed and objects inspected.also when the library with the compiled code of these classes is missing The schema evolution mechanism supports the frequent case when multiple data sets generated with many different class versions must be analyzed in the same session.ROOT supports the automatic generation of C++ code describing the data objects in a file.
Physics of Automatic Target Recognition
Sadjadi, Firooz
2007-01-01
Physics of Automatic Target Recognition addresses the fundamental physical bases of sensing, and information extraction in the state-of-the art automatic target recognition field. It explores both passive and active multispectral sensing, polarimetric diversity, complex signature exploitation, sensor and processing adaptation, transformation of electromagnetic and acoustic waves in their interactions with targets, background clutter, transmission media, and sensing elements. The general inverse scattering, and advanced signal processing techniques and scientific evaluation methodologies being used in this multi disciplinary field will be part of this exposition. The issues of modeling of target signatures in various spectral modalities, LADAR, IR, SAR, high resolution radar, acoustic, seismic, visible, hyperspectral, in diverse geometric aspects will be addressed. The methods for signal processing and classification will cover concepts such as sensor adaptive and artificial neural networks, time reversal filt...
Automatic schema evolution in Root
International Nuclear Information System (INIS)
ROOT version 3 (spring 2001) supports automatic class schema evolution. In addition this version also produces files that are self-describing. This is achieved by storing in each file a record with the description of all the persistent classes in the file. Being self-describing guarantees that a file can always be read later, its structure browsed and objects inspected, also when the library with the compiled code of these classes is missing. The schema evolution mechanism supports the frequent case when multiple data sets generated with many different class versions must be analyzed in the same session. ROOT supports the automatic generation of C++ code describing the data objects in a file
Automatic spikes detection in seismogram
Institute of Scientific and Technical Information of China (English)
王海军; 靳平; 刘贵忠
2003-01-01
@@ Data processing for seismic network is very complex and fussy, because a lot of data is recorded in seismic network every day, which make it impossible to process these data all by manual work. Therefore, seismic data should be processed automatically to produce a initial results about events detection and location. Afterwards, these results are reviewed and modified by analyst. In automatic processing data quality checking is important. There are three main problem data thatexist in real seismic records, which include: spike, repeated data and dropouts. Spike is defined as isolated large amplitude point; the other two problem datahave the same features that amplitude of sample points are uniform in a interval. In data quality checking, the first step is to detect and statistic problem data in a data segment, if percent of problem data exceed a threshold, then the whole data segment is masked and not be processed in the later process.
Automatic registration of satellite imagery
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.
The Automatic Galaxy Collision Software
Smith, Beverly J; Pfeiffer, Phillip; Perkins, Sam; Barkanic, Jason; Fritts, Steve; Southerland, Derek; Manchikalapudi, Dinikar; Baker, Matt; Luckey, John; Franklin, Coral; Moffett, Amanda; Struck, Curtis
2009-01-01
The key to understanding the physical processes that occur during galaxy interactions is dynamical modeling, and especially the detailed matching of numerical models to specific systems. To make modeling interacting galaxies more efficient, we have constructed the `Automatic Galaxy Collision' (AGC) code, which requires less human intervention in finding good matches to data. We present some preliminary results from this code for the well-studied system Arp 284 (NGC 7714/5), and address questions of uniqueness of solutions.
Automatic Generation of Technical Documentation
Reiter, Ehud; Mellish, Chris; Levine, John
1994-01-01
Natural-language generation (NLG) techniques can be used to automatically produce technical documentation from a domain knowledge base and linguistic and contextual models. We discuss this application of NLG technology from both a technical and a usefulness (costs and benefits) perspective. This discussion is based largely on our experiences with the IDAS documentation-generation project, and the reactions various interested people from industry have had to IDAS. We hope that this summary of ...
Annual review in automatic programming
Halpern, Mark I; Bolliet, Louis
2014-01-01
Computer Science and Technology and their Application is an eight-chapter book that first presents a tutorial on database organization. Subsequent chapters describe the general concepts of Simula 67 programming language; incremental compilation and conversational interpretation; dynamic syntax; the ALGOL 68. Other chapters discuss the general purpose conversational system for graphical programming and automatic theorem proving based on resolution. A survey of extensible programming language is also shown.
Automatically constructing the semantic web
Becerra, Victor Manuel; Brown, Matthew; Nasuto, Slawomir
2008-01-01
The storage and processing capacity realised by computing has lead to an explosion of data retention. We now reach the point of information overload and must begin to use computers to process more complex information. In particular, the proposition of the Semantic Web has given structure to this problem, but has yet realised practically. The largest of its problems is that of ontology construction; without a suitable automatic method most will have to be encoded by hand. In this paper we disc...
Approaches to Automatic Text Structuring
Erbs, Nicolai
2015-01-01
Structured text helps readers to better understand the content of documents. In classic newspaper texts or books, some structure already exists. In the Web 2.0, the amount of textual data, especially user-generated data, has increased dramatically. As a result, there exists a large amount of textual data which lacks structure, thus making it more difficult to understand. In this thesis, we will explore techniques for automatic text structuring to help readers to fulfill their information need...
The Automatic Measurement of Targets
DEFF Research Database (Denmark)
Höhle, Joachim
1997-01-01
The automatic measurement of targets is demonstrated by means of a theoretical example and by an interactive measuring program for real imagery from a réseau camera. The used strategy is a combination of two methods: the maximum correlation coefficient and the correlation in the subpixel range. F...... interactive software is also part of a computer-assisted learning program on digital photogrammetry....
Automatically-Programed Machine Tools
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.
Automatic translation among spoken languages
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.
Social influence effects on automatic racial prejudice.
Lowery, B S; Hardin, C D; Sinclair, S
2001-11-01
Although most research on the control of automatic prejudice has focused on the efficacy of deliberate attempts to suppress or correct for stereotyping, the reported experiments tested the hypothesis that automatic racial prejudice is subject to common social influence. In experiments involving actual interethnic contact, both tacit and expressed social influence reduced the expression of automatic prejudice, as assessed by two different measures of automatic attitudes. Moreover, the automatic social tuning effect depended on participant ethnicity. European Americans (but not Asian Americans) exhibited less automatic prejudice in the presence of a Black experimenter than a White experimenter (Experiments 2 and 4), although both groups exhibited reduced automatic prejudice when instructed to avoid prejudice (Experiment 3). Results are consistent with shared reality theory, which postulates that social regulation is central to social cognition. PMID:11708561
Automatic hypermnesia and impaired recollection in schizophrenia.
Linscott, R J; Knight, R G
2001-10-01
Evidence from studies of nonmnemonic automatic cognitive processes provides reason to expect that schizophrenia is associated with exaggerated automatic memory (implicit memory), or automatic hypermnesia. Participants with schizophrenia (n = 22) and control participants (n = 26) were compared on word stem completion (WSC) and list discrimination (LD) tasks administered using the process dissociation procedure. Unadjusted, extended measurement model and dual-process signal-detection methods were used to estimate recollection and automatic memory indices. Schizophrenia was associated with automatic hypermnesia on the WSC task and impaired recollection on both tasks. Thought disorder was associated with even greater automatic hypermnesia. The absence of automatic hypermnesia on the LD task was interpreted with reference to the neuropsychological bases of context and content memory. PMID:11761047
Unification of automatic target tracking and automatic target recognition
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.
Annual review in automatic programming
Goodman, Richard
2014-01-01
Annual Review in Automatic Programming, Volume 2 is a collection of papers that discusses the controversy about the suitability of COBOL as a common business oriented language, and the development of different common languages for scientific computation. A couple of papers describes the use of the Genie system in numerical calculation and analyzes Mercury autocode in terms of a phrase structure language, such as in the source language, target language, the order structure of ATLAS, and the meta-syntactical language of the assembly program. Other papers explain interference or an ""intermediate
Automatic Generation of Technical Documentation
Reiter, E R; Levine, J; Reiter, Ehud; Mellish, Chris; Levine, John
1994-01-01
Natural-language generation (NLG) techniques can be used to automatically produce technical documentation from a domain knowledge base and linguistic and contextual models. We discuss this application of NLG technology from both a technical and a usefulness (costs and benefits) perspective. This discussion is based largely on our experiences with the IDAS documentation-generation project, and the reactions various interested people from industry have had to IDAS. We hope that this summary of our experiences with IDAS and the lessons we have learned from it will be beneficial for other researchers who wish to build technical-documentation generation systems.
Unsupervised automatic music genre classification
Barreira, Luís Filipe Marques
2010-01-01
Trabalho apresentado no âmbito do Mestrado em Engenharia Informática, como requisito parcial para obtenção do grau de Mestre em Engenharia Informática In this study we explore automatic music genre recognition and classification of digital music. Music has always been a reflection of culture di erences and an influence in our society. Today’s digital content development triggered the massive use of digital music. Nowadays,digital music is manually labeled without following a universa...
Real time automatic scene classification
Israël, Menno; Broek, van den, Wouter; Putten, van, M.J.A.M.; Uyl, den, T.M.; Verbrugge, R.; Taatgen, N.; Schomaker, L.
2004-01-01
This work has been done as part of the EU VICAR (IST) project and the EU SCOFI project (IAP). The aim of the first project was to develop a real time video indexing classification annotation and retrieval system. For our systems, we have adapted the approach of Picard and Minka [3], who categorized elements of a scene automatically with so-called ’stuff’ categories (e.g., grass, sky, sand, stone). Campbell et al. [1] use similar concepts to describe certain parts of an image, which they named...
Annual review in automatic programming
Goodman, Richard
2014-01-01
Annual Review in Automatic Programming, Volume 4 is a collection of papers that deals with the GIER ALGOL compiler, a parameterized compiler based on mechanical linguistics, and the JOVIAL language. A couple of papers describes a commercial use of stacks, an IBM system, and what an ideal computer program support system should be. One paper reviews the system of compilation, the development of a more advanced language, programming techniques, machine independence, and program transfer to other machines. Another paper describes the ALGOL 60 system for the GIER machine including running ALGOL pro
Automatic transcription of polyphonic singing
Paščinski, Uroš
2015-01-01
In this work we focus on automatic transcription of polyphonic singing. In particular we do the multiple fundamental frequency (F0) estimation. From the terrain recordings a test set of Slovenian folk songs with polyphonic singing is extracted and manually transcribed. On the test set we try the general algorithm for multiple F0 detection. An interactive visualization of the main parts of the algorithm is made to analyse how it works and try to detect possible issues. As the data set is ne...
Automatic analysis of multiparty meetings
Indian Academy of Sciences (India)
Steve Renals
2011-10-01
This paper is about the recognition and interpretation of multiparty meetings captured as audio, video and other signals. This is a challenging task since the meetings consist of spontaneous and conversational interactions between a number of participants: it is a multimodal, multiparty, multistream problem. We discuss the capture and annotation of the Augmented Multiparty Interaction (AMI) meeting corpus, the development of a meeting speech recognition system, and systems for the automatic segmentation, summarization and social processing of meetings, together with some example applications based on these systems.
Coordinated hybrid automatic repeat request
Makki, Behrooz
2014-11-01
We develop a coordinated hybrid automatic repeat request (HARQ) approach. With the proposed scheme, if a user message is correctly decoded in the first HARQ rounds, its spectrum is allocated to other users, to improve the network outage probability and the users\\' fairness. The results, which are obtained for single- and multiple-antenna setups, demonstrate the efficiency of the proposed approach in different conditions. For instance, with a maximum of M retransmissions and single transmit/receive antennas, the diversity gain of a user increases from M to (J+1)(M-1)+1 where J is the number of users helping that user.
Automatic generation of tourist brochures
Birsak, Michael
2014-05-01
We present a novel framework for the automatic generation of tourist brochures that include routing instructions and additional information presented in the form of so-called detail lenses. The first contribution of this paper is the automatic creation of layouts for the brochures. Our approach is based on the minimization of an energy function that combines multiple goals: positioning of the lenses as close as possible to the corresponding region shown in an overview map, keeping the number of lenses low, and an efficient numbering of the lenses. The second contribution is a route-aware simplification of the graph of streets used for traveling between the points of interest (POIs). This is done by reducing the graph consisting of all shortest paths through the minimization of an energy function. The output is a subset of street segments that enable traveling between all the POIs without considerable detours, while at the same time guaranteeing a clutter-free visualization. © 2014 The Author(s) Computer Graphics Forum © 2014 The Eurographics Association and John Wiley & Sons Ltd. Published by John Wiley & Sons Ltd.
Automatic scanning for nuclear emulsion
International Nuclear Information System (INIS)
Automatic scanning systems have been recently developed for application in neutrino experiments exploiting nuclear emulsion detectors of particle tracks. These systems speed up substantially the analysis of events in emulsion, allowing the realisation of experiments with unprecedented statistics. The pioneering work on automatic scanning has been done by the University of Nagoya (Japan). The so called new track selector has a very good reproducibility in position (∼1 μm) and angle (∼3 mrad), with the possibility to reconstruct, in about 3 s, all the tracks in a view of 150x150 μm2 and 1 mm of thickness. A new system (ultratrack selector), with speed higher by one order of magnitude, has started to be in operation. R and D programs are going on in Nagoya and in other laboratories for new systems. The scanning speed in nuclear emulsion be further increased by an order of magnitude. The recent progress in the technology of digital signal processing and of image acquisition systems (CCDs and fast frame grabbers) allows the realisation of systems with high performance. New interesting applications of the technique in other fields (e.g. in biophysics) have recently been envisaged
International Nuclear Information System (INIS)
Automatic handling device for the steam relief valves (SRV's) is developed in order to achieve a decrease in exposure of workers, increase in availability factor, improvement in reliability, improvement in safety of operation, and labor saving. A survey is made during a periodical inspection to examine the actual SVR handling operation. An SRV automatic handling device consists of four components: conveyor, armed conveyor, lifting machine, and control/monitoring system. The conveyor is so designed that the existing I-rail installed in the containment vessel can be used without any modification. This is employed for conveying an SRV along the rail. The armed conveyor, designed for a box rail, is used for an SRV installed away from the rail. By using the lifting machine, an SRV installed away from the I-rail is brought to a spot just below the rail so that the SRV can be transferred by the conveyor. The control/monitoring system consists of a control computer, operation panel, TV monitor and annunciator. The SRV handling device is operated by remote control from a control room. A trial equipment is constructed and performance/function testing is carried out using actual SRV's. As a result, is it shown that the SRV handling device requires only two operators to serve satisfactorily. The required time for removal and replacement of one SRV is about 10 minutes. (Nogami, K.)
Automatic validation of numerical solutions
DEFF Research Database (Denmark)
Stauning, Ole
1997-01-01
This thesis is concerned with ``Automatic Validation of Numerical Solutions''. The basic theory of interval analysis and self-validating methods is introduced. The mean value enclosure is applied to discrete mappings for obtaining narrow enclosures of the iterates when applying these mappings wit...... the mean value enclosure of an integral operator and uses interval Bernstein polynomials for enclosing the solution. Two numerical examples are given, using two orders of approximation and using different numbers of discretization points.......This thesis is concerned with ``Automatic Validation of Numerical Solutions''. The basic theory of interval analysis and self-validating methods is introduced. The mean value enclosure is applied to discrete mappings for obtaining narrow enclosures of the iterates when applying these mappings with...... intervals as initial values. A modification of the mean value enclosure of discrete mappings is considered, namely the extended mean value enclosure which in most cases leads to even better enclosures. These methods have previously been described in connection with discretizing solutions of ordinary...
Automatic Differentiation of Algorithms for Machine Learning
Baydin, Atilim Gunes; Pearlmutter, Barak A.
2014-01-01
Automatic differentiation --- the mechanical transformation of numeric computer programs to calculate derivatives efficiently and accurately --- dates to the origin of the computer age. Reverse mode automatic differentiation both antedates and generalizes the method of backwards propagation of errors used in machine learning. Despite this, practitioners in a variety of fields, including machine learning, have been little influenced by automatic differentiation, and make scant use of available...
Automatic Speech Segmentation Based on HMM
M. Kroul
2007-01-01
This contribution deals with the problem of automatic phoneme segmentation using HMMs. Automatization of speech segmentation task is important for applications, where large amount of data is needed to process, so manual segmentation is out of the question. In this paper we focus on automatic segmentation of recordings, which will be used for triphone synthesis unit database creation. For speech synthesis, the speech unit quality is a crucial aspect, so the maximal accuracy in segmentation is ...
Automatic Control of Water Pumping Stations
Institute of Scientific and Technical Information of China (English)
Muhannad Alrheeh; JIANG Zhengfeng
2006-01-01
Automatic Control of pumps is an interesting proposal to operate water pumping stations among many kinds of water pumping stations according to their functions.In this paper, our pumping station is being used for water supply system. This paper is to introduce the idea of pump controller and the important factors that must be considering when we want to design automatic control system of water pumping stations. Then the automatic control circuit with the function of all components will be introduced.
Automatic inference of specifications using matching logic
Alpuente Frasnedo, María; Feliú Gabaldón, Marco Antonio; Villanueva García, Alicia
2013-01-01
Formal specifications can be used for various software engineering activities ranging from finding errors to documenting software and automatic test-case generation. Automatically discovering specifications for heap-manipulating programs is a challenging task. In this paper, we propose a technique for automatically inferring formal specifications from C code which is based on the symbolic execution and automated reasoning tandem "MATCHING LOGIC /K framework". We implemented our technique for ...
An automatic visual analysis system for tennis
Connaghan, Damien; Moran, Kieran; O''Connor, Noel E.
2013-01-01
This article presents a novel video analysis system for coaching tennis players of all levels, which uses computer vision algorithms to automatically edit and index tennis videos into meaningful annotations. Existing tennis coaching software lacks the ability to automatically index a tennis match into key events, and therefore, a coach who uses existing software is burdened with time-consuming manual video editing. This work aims to explore the effectiveness of a system to automatically de...
ANPS - AUTOMATIC NETWORK PROGRAMMING SYSTEM
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
Automatic gamma spectrometry analytical apparatus
International Nuclear Information System (INIS)
This invention falls within the area of quantitative or semi-quantitative analysis by gamma spectrometry and particularly refers to a device for bringing the samples into the counting position. The purpose of this invention is precisely to provide an automatic apparatus specifically adapted to the analysis of hard gamma radiations. To this effect, the invention relates to a gamma spectrometry analytical device comprising a lead containment, a detector of which the sensitive part is located inside the containment and additionally comprising a transfer system for bringing the analyzed samples in succession to a counting position inside the containment above the detector. A feed compartment enables the samples to be brought in turn one by one on to the transfer system through a duct connecting the compartment to the transfer system. Sequential systems for the coordinated forward feed of the samples in the compartment and the transfer system complete this device
Automatic home medical product recommendation.
Luo, Gang; Thomas, Selena B; Tang, Chunqiang
2012-04-01
Web-based personal health records (PHRs) are being widely deployed. To improve PHR's capability and usability, we proposed the concept of intelligent PHR (iPHR). In this paper, we use automatic home medical product recommendation as a concrete application to demonstrate the benefits of introducing intelligence into PHRs. In this new application domain, we develop several techniques to address the emerging challenges. Our approach uses treatment knowledge and nursing knowledge, and extends the language modeling method to (1) construct a topic-selection input interface for recommending home medical products, (2) produce a global ranking of Web pages retrieved by multiple queries, and (3) provide diverse search results. We demonstrate the effectiveness of our techniques using USMLE medical exam cases. PMID:20703712
Automatic sampling of radioactive liquors
International Nuclear Information System (INIS)
This paper describes the latest techniques in sampling radioactive liquors in an Irradiated Fuel Reprocessing Plant. Previously to obtain a sample from these liquors operators were involved at the point of sampling, the transport of samples in shielded containers to the laboratories and at the offloading of the samples at the laboratory. Penetration of the radioactive containments occurred at the sampling point and again in the laboratory, these operations could lead to possible radioactive contamination. The latest design consists of a Sample Bottle Despatch Facility Autosampler units, Pneumatic Transfer System and Receipt Facility which reduces considerably operator involvement, provides a safe rapid transport system and minimises any possibility of radioactive contamination. The system can be made fully automatic and ease of maintenance has been ensured by the design
Automatic sampling of radioactive liquors
International Nuclear Information System (INIS)
This paper describes the latest techniques in sampling radioactive liquors in an Irradiated Fuel Reprocessing Plant. Previously to obtain a sample from these liquors operators were involved at the point of sampling, the transport of samples in shielded containers to the laboratories and at the offloading of the samples at the laboratory. Penetration of the radioactive containments occurred at the sampling point and again in the laboratory, these operations could lead to possible radioactive contamination. The latest design consists of a Sample Bottle Despatch Facility Autosampler units, Pneumatic Transfer System and Receipt Facility which reduces considerably operator involvement, provides a safe rapid transport system and minimises any possibility of radioactive contamination. The system can be made fully automatic and ease of maintenance has been ensured by the design. (author)
Automatic sampling of radioactive liquors
International Nuclear Information System (INIS)
The latest techniques in sampling radioactive liquors in an Irradiated Fuel Reprocessing Plant are described. Previously to obtain a sample from these liquors operators were involved at the point of sampling, the transport of samples in shielded containers to the laboratories and at the offloading of the samples at the laboratory. Penetration of the radioactive containments occurred at the sampling point and again in the laboratory; these operations could lead to possible radioactive contamination. The latest design consists of a Sample Bottle Despatch Facility Autosampler units, Pneumatic Transfer System and Receipt Facility which reduces considerably operator involvement, provides a safe rapid transport system and minimises any possibility of radioactive contamination. The system can be made fully automatic and ease of maintenance has been ensured by the design. (author)
Automatic Sequencing for Experimental Protocols
Hsieh, Paul F.; Stern, Ivan
We present a paradigm and implementation of a system for the specification of the experimental protocols to be used for the calibration of AXAF mirrors. For the mirror calibration, several thousand individual measurements need to be defined. For each measurement, over one hundred parameters need to be tabulated for the facility test conductor and several hundred instrument parameters need to be set. We provide a high level protocol language which allows for a tractable representation of the measurement protocol. We present a procedure dispatcher which automatically sequences a protocol more accurately and more rapidly than is possible by an unassisted human operator. We also present back-end tools to generate printed procedure manuals and database tables required for review by the AXAF program. This paradigm has been tested and refined in the calibration of detectors to be used in mirror calibration.
Autoclass: An automatic classification system
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.
Techniques for automatic speech recognition
Moore, R. K.
1983-05-01
A brief insight into some of the algorithms that lie behind current automatic speech recognition system is provided. Early phonetically based approaches were not particularly successful, due mainly to a lack of appreciation of the problems involved. These problems are summarized, and various recognition techniques are reviewed in the contect of the solutions that they provide. It is pointed out that the majority of currently available speech recognition equipments employ a "whole-word' pattern matching approach which, although relatively simple, has proved particularly successful in its ability to recognize speech. The concepts of time-normalizing plays a central role in this type of recognition process and a family of such algorithms is described in detail. The technique of dynamic time warping is not only capable of providing good performance for isolated word recognition, but how it is also extended to the recognition of connected speech (thereby removing one of the most severe limitations of early speech recognition equipment).
Automatic force balance calibration system
Ferris, Alice T.
1995-05-01
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 +/-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.
Methods of automatic scanning of SSNTDs
International Nuclear Information System (INIS)
The methods of automatic scanning of solid state nuclear track detectors are reviewed. The paper deals with transmission of light, charged particles, chemicals and electrical current through conventionally etched detectors. Special attention is given to the jumping spark technique and breakdown counters. Eventually optical automatic devices are examined. (orig.)
Automatic control of nuclear power plants
International Nuclear Information System (INIS)
The fundamental concepts in automatic control are surveyed, and the purpose of the automatic control of pressurized water reactors is given. The response characteristics for the main components are then studied and block diagrams are given for the main control loops (turbine, steam generator, and nuclear reactors)
Towards unifying inheritance and automatic program specialization
DEFF Research Database (Denmark)
Schultz, Ulrik Pagh
2002-01-01
inheritance with covariant specialization to control the automatic application of program specialization to class members. Lapis integrates object-oriented concepts, block structure, and techniques from automatic program specialization to provide both a language where object-oriented designs can be e...
ANNUAL REPORT-AUTOMATIC INDEXING AND ABSTRACTING.
Lockheed Missiles and Space Co., Palo Alto, CA. Electronic Sciences Lab.
THE INVESTIGATION IS CONCERNED WITH THE DEVELOPMENT OF AUTOMATIC INDEXING, ABSTRACTING, AND EXTRACTING SYSTEMS. BASIC INVESTIGATIONS IN ENGLISH MORPHOLOGY, PHONETICS, AND SYNTAX ARE PURSUED AS NECESSARY MEANS TO THIS END. IN THE FIRST SECTION THE THEORY AND DESIGN OF THE "SENTENCE DICTIONARY" EXPERIMENT IN AUTOMATIC EXTRACTION IS OUTLINED. SOME OF…
Solar Powered Automatic Shrimp Feeding System
Directory of Open Access Journals (Sweden)
Dindo T. Ani
2015-12-01
Full Text Available - Automatic system has brought many revolutions in the existing technologies. One among the technologies, which has greater developments, is the solar powered automatic shrimp feeding system. For instance, the solar power which is a renewable energy can be an alternative solution to energy crisis and basically reducing man power by using it in an automatic manner. The researchers believe an automatic shrimp feeding system may help solve problems on manual feeding operations. The project study aimed to design and develop a solar powered automatic shrimp feeding system. It specifically sought to prepare the design specifications of the project, to determine the methods of fabrication and assembly, and to test the response time of the automatic shrimp feeding system. The researchers designed and developed an automatic system which utilizes a 10 hour timer to be set in intervals preferred by the user and will undergo a continuous process. The magnetic contactor acts as a switch connected to the 10 hour timer which controls the activation or termination of electrical loads and powered by means of a solar panel outputting electrical power, and a rechargeable battery in electrical communication with the solar panel for storing the power. By undergoing through series of testing, the components of the modified system were proven functional and were operating within the desired output. It was recommended that the timer to be used should be tested to avoid malfunction and achieve the fully automatic system and that the system may be improved to handle changes in scope of the project.
AUTOMATIC DESIGNING OF POWER SUPPLY SYSTEMS
Directory of Open Access Journals (Sweden)
A. I. Kirspou
2016-01-01
Full Text Available Development of automatic designing system for power supply of industrial enterprises is considered in the paper. Its complete structure and principle of operation are determined and established. Modern graphical interface and data scheme are developed, software is completely realized. Methodology and software correspond to the requirements of the up-to-date designing, describe a general algorithm of program process and also reveals properties of automatic designing system objects. Automatic designing system is based on module principle while using object-orientated programming. Automatic designing system makes it possible to carry out consistently designing calculations of power supply system and select the required equipment with subsequent output of all calculations in the form of explanatory note. Automatic designing system can be applied by designing organizations under conditions of actual designing.
Automatic Performance Debugging of SPMD Parallel Programs
Liu, Xu; Zhan, Jianfeng; Tu, Bibo; Meng, Dan
2010-01-01
Automatic performance debugging of parallel applications usually involves two steps: automatic detection of performance bottlenecks and uncovering their root causes for performance optimization. Previous work fails to resolve this challenging issue in several ways: first, several previous efforts automate analysis processes, but present the results in a confined way that only identifies performance problems with apriori knowledge; second, several tools take exploratory or confirmatory data analysis to automatically discover relevant performance data relationships. However, these efforts do not focus on locating performance bottlenecks or uncovering their root causes. In this paper, we design and implement an innovative system, AutoAnalyzer, to automatically debug the performance problems of single program multi-data (SPMD) parallel programs. Our system is unique in terms of two dimensions: first, without any apriori knowledge, we automatically locate bottlenecks and uncover their root causes for performance o...
Automatic reactor power control device
International Nuclear Information System (INIS)
Anticipated transient without scram (ATWS) of a BWR type reactor is judged to generate a signal based on a reactor power signal and a scram actuation demand signal. The ATWS signal and a predetermined water level signal to be generated upon occurrence of ATWS are inputted, and an injection water flow rate signal exhibiting injection water flow rate optimum to reactor flooding and power suppression is outputted. In addition, a reactor pressure setting signal is outputted based on injection performance of a high pressure water injection system or a lower pressure water injection system upon occurrence of ATWS. Further, the reactor pressure setting signal is inputted to calculate opening/closing setting pressure of a main steam relief valve and output an opening setting pressure signal and a closure setting pressure signal for the main steam relief valve. As a result, the reactor power and the reactor water level can be automatically controlled even upon occurrence of ATWS due to failure of insertion of all of the control rods thereby enabling to maintain integrity and safety of the reactor, the reactor pressure vessel and the reactor container. (N.H.)
Pattern-Driven Automatic Parallelization
Directory of Open Access Journals (Sweden)
Christoph W. Kessler
1996-01-01
Full Text Available This article describes a knowledge-based system for automatic parallelization of a wide class of sequential numerical codes operating on vectors and dense matrices, and for execution on distributed memory message-passing multiprocessors. Its main feature is a fast and powerful pattern recognition tool that locally identifies frequently occurring computations and programming concepts in the source code. This tool also works for dusty deck codes that have been "encrypted" by former machine-specific code transformations. Successful pattern recognition guides sophisticated code transformations including local algorithm replacement such that the parallelized code need not emerge from the sequential program structure by just parallelizing the loops. It allows access to an expert's knowledge on useful parallel algorithms, available machine-specific library routines, and powerful program transformations. The partially restored program semantics also supports local array alignment, distribution, and redistribution, and allows for faster and more exact prediction of the performance of the parallelized target code than is usually possible.
Traceability Through Automatic Program Generation
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.
Extensometer automatically measures elongation in elastomers
Hooper, C. D.
1966-01-01
Extensometer, with a calibrated shaft, measures the elongation of elastomers and automatically records this distance on a chart. It is adaptable to almost any tensile testing machine and is fabricated at a relatively low cost.
2010 United States Automatic Identification System Database
National Oceanic and Atmospheric Administration, Department of Commerce — The 2010 United States Automatic Identification System Database contains vessel traffic data for planning purposes within the U.S. coastal waters. The database is...
Computer systems for automatic earthquake detection
Stewart, S.W.
1974-01-01
U.S Geological Survey seismologists in Menlo park, California, are utilizing the speed, reliability, and efficiency of minicomputers to monitor seismograph stations and to automatically detect earthquakes. An earthquake detection computer system, believed to be the only one of its kind in operation, automatically reports about 90 percent of all local earthquakes recorded by a network of over 100 central California seismograph stations. The system also monitors the stations for signs of malfunction or abnormal operation. Before the automatic system was put in operation, all of the earthquakes recorded had to be detected by manually searching the records, a time-consuming process. With the automatic detection system, the stations are efficiently monitored continuously.
Automatic program debugging for intelligent tutoring systems
Energy Technology Data Exchange (ETDEWEB)
Murray, W.R.
1986-01-01
This thesis explores the process by which student programs can be automatically debugged in order to increase the instructional capabilities of these systems. This research presents a methodology and implementation for the diagnosis and correction of nontrivial recursive programs. In this approach, recursive programs are debugged by repairing induction proofs in the Boyer-Moore Logic. The potential of a program debugger to automatically debug widely varying novice programs in a nontrivial domain is proportional to its capabilities to reason about computational semantics. By increasing these reasoning capabilities a more powerful and robust system can result. This thesis supports these claims by examining related work in automated program debugging and by discussing the design, implementation, and evaluation of Talus, an automatic degugger for LISP programs. Talus relies on its abilities to reason about computational semantics to perform algorithm recognition, infer code teleology, and to automatically detect and correct nonsyntactic errors in student programs written in a restricted, but nontrivial, subset of LISP.
Variable load automatically tests dc power supplies
Burke, H. C., Jr.; Sullivan, R. M.
1965-01-01
Continuously variable load automatically tests dc power supplies over an extended current range. External meters monitor current and voltage, and multipliers at the outputs facilitate plotting the power curve of the unit.
2012 United States Automatic Identification System Database
National Oceanic and Atmospheric Administration, Department of Commerce — The 2012 United States Automatic Identification System Database contains vessel traffic data for planning purposes within the U.S. coastal waters. The database is...
Coke oven automatic combustion control system
Energy Technology Data Exchange (ETDEWEB)
Shihara, Y.
1981-01-01
This article describes and discusses the development and application of an automatic combustion control system for coke ovens that has been used at the Yawata Works of the Nippon Steel Corporation, Japan. (In Japanese)
2014 United States Automatic Identification System Database
National Oceanic and Atmospheric Administration, Department of Commerce — The 2014 United States Automatic Identification System Database contains vessel traffic data for planning purposes within the U.S. coastal waters. The database is...
2009 United States Automatic Identification System Database
National Oceanic and Atmospheric Administration, Department of Commerce — The 2009 United States Automatic Identification System Database contains vessel traffic data for planning purposes within the U.S. coastal waters. The database is...
Automatic calibration system for pressure transducers
1968-01-01
Fifty-channel automatic pressure transducer calibration system increases quantity and accuracy for test evaluation calibration. The pressure transducers are installed in an environmental tests chamber and manifolded to connect them to a pressure balance which is uniform.
A Demonstration of Automatically Switched Optical Network
Institute of Scientific and Technical Information of China (English)
无
2003-01-01
We build an automatically switched optical network (ASON) testbed with four optical cross-connect nodes. Many fundamental ASON features are demonstrated, which is implemented by control protocols based on generalized multi-protocol label switching (GMPLS) framework.
The problem of automatic identification of concepts
International Nuclear Information System (INIS)
This paper deals with the problem of the automatic recognition of concepts and describes an important language tool, the ''linguistic filter'', which facilitates the construction of statistical algorithms. Certain special filters, of prepositions, conjunctions, negatives, logical implication, compound words, are presented. This is followed by a detailed description of a statistical algorithm allowing recognition of pronoun referents, and finally the problem of the automatic treatment of negatives in French is discussed
Automatic text categorisation of racist webpages
Greevy, Edel
2004-01-01
Automatic Text Categorisation (TC) involves the assignment of one or more predefined categories to text documents in order that they can be effectively managed. In this thesis we examine the possibility of applying automatic text categorisation to the problem of categorising texts (web pages) based on whether or not they are racist. TC has proven successful for topic-based problems such as news story categorisation. However, the problem of detecting racism is dissimilar to topic-based pro...
Development of automatic weld strength testing machine
International Nuclear Information System (INIS)
In order to improve the testing process and accuracy so as to carry out all the manual works including documentation automatically and effortlessly, an automatic computerised strength testing machine with the latest state-of-art technology, including both the hardware and software was developed. The operator has to only submit the weld to the machine for testing and start the testing process merely by pressing a switch. This paper depicts the salient features of this machine
Dynamic Automatic Noisy Speech Recognition System (DANSR)
Paul, Sheuli
2014-01-01
In this thesis we studied and investigated a very common but a long existing noise problem and we provided a solution to this problem. The task is to deal with different types of noise that occur simultaneously and which we call hybrid. Although there are individual solutions for specific types one cannot simply combine them because each solution affects the whole speech. We developed an automatic speech recognition system DANSR ( Dynamic Automatic Noisy Speech Recognition System) for hybri...
AUTOMATIC CAPTION GENERATION FOR ELECTRONICS TEXTBOOKS
Veena Thakur; Trupti Gedam
2015-01-01
Automatic or semi-automatic approaches for developing Technology Supported Learning Systems (TSLS) are required to lighten their development cost. The main objective of this paper is to automate the generation of a caption module; it aims at reproducing the way teachers prepare their lessons and the learning material they will use throughout the course. Teachers tend to choose one or more textbooks that cover the contents of their subjects, determine the topics to be addressed, and identify...
Automatic Morphometry of Nerve Histological Sections
Romero, E.; Cuisenaire, O.; Denef, J.; Delbeke, J.; Macq, B.; Veraart, C.
2000-01-01
A method for the automatic segmentation, recognition and measurement of neuronal myelinated fibers in nerve histological sections is presented. In this method, the fiber parameters i.e. perimeter, area, position of the fiber and myelin sheath thickness are automatically computed. Obliquity of the sections may be taken into account. First, the image is thresholded to provide a coarse classification between myelin and non-myelin pixels. Next, the resulting binary image is further simplified usi...
An automatic system for multielement solvent extractions
International Nuclear Information System (INIS)
The automatic system described is suitable for multi-element separations by solvent extraction techniques with organic solvents heavier than water. The analysis is run automatically by a central control unit and includes steps such as pH regulation and reduction or oxidation. As an example, the separation of radioactive Hg2+, Cu2+, Mo6+, Cd2+, As5+, Sb5+, Fe3+, and Co3+ by means of diethyldithiocarbonate complexes is reported. (Auth.)
Automatic terrain modeling using transfinite element analysis
Collier, Nathaniel O.
2010-05-31
An automatic procedure for modeling terrain is developed based on L2 projection-based interpolation of discrete terrain data onto transfinite function spaces. The function space is refined automatically by the use of image processing techniques to detect regions of high error and the flexibility of the transfinite interpolation to add degrees of freedom to these areas. Examples are shown of a section of the Palo Duro Canyon in northern Texas.
Evaluation framework for automatic singing transcription
Molina, Emilio; Ana M. Barbancho; Tardón, Lorenzo J.; Barbancho, Isabel
2014-01-01
In this paper, we analyse the evaluation strategies used in previous works on automatic singing transcription, and we present a novel, comprehensive and freely available evaluation framework for automatic singing transcription. This framework consists of a cross-annotated dataset and a set of extended evaluation measures, which are integrated in a Matlab toolbox. The presented evaluation measures are based on standard MIREX note-tracking measures, but they provide extra information about the ...
Automatic Programming with Ant Colony Optimization
Green, Jennifer; Jacqueline L. Whalley; Johnson, Colin G.
2004-01-01
Automatic programming is the use of search techniques to find programs that solve a problem. The most commonly explored automatic programming technique is genetic programming, which uses genetic algorithms to carry out the search. In this paper we introduce a new technique called Ant Colony Programming (ACP) which uses an ant colony based search in place of genetic algorithms. This algorithm is described and compared with other approaches in the literature.
Face-Based Automatic Personality Perception
Al Moubayed, Noura; Vazquez-Alvarez, Yolanda; McKay, Alex; Vinciarelli, Alessandro
2014-01-01
Automatic Personality Perception is the task of automatically predicting the personality traits people attribute to others. This work presents experiments where such a task is performed by mapping facial appearance into the Big-Five personality traits, namely Openness, Conscientiousness, Extraversion, Agreeableness and Neuroticism. The experiments are performed over the pictures of the FERET corpus, originally collected for biometrics purposes, for a total of 829 individuals. The results show...
Automatic processing of dominance and submissiveness
Moors, Agnes; De Houwer, Jan
2005-01-01
We investigated whether people are able to detect in a relatively automatic manner the dominant or submissive status of persons engaged in social interactions. Using a variant of the affective Simon task (De Houwer & Eelen, 1998), we demonstrated that the verbal response DOMINANT or SUBMISSIVE was facilitated when it had to be made to a target person that was respectively dominant or submissive. These results provide new information about the automatic nature of appraisals and ...
Production from multiple zones of a tar sands formation
Energy Technology Data Exchange (ETDEWEB)
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.
Automatic welding techniques for nuclear power plants
International Nuclear Information System (INIS)
Improved type BWRs (ABWR) further heightened the operation properties, safety and economic efficiency as the synthetic characteristics of the plants by simplification and the heightening of performance. Especially, reactor internal pumps (RIP) together with improved control rod driving (CRD) system promoted the simplification of reactor system and the improvement of operation properties and safety. The structures of RIP casing proper and the welded parts, the automatic TIG welder for RIP casings and the nondestructive inspection after the welding, the three-dimensional automatic welding of CRD stubs, the narrow gap welding of flow nozzles and the automatic welding of spent fuel storage racks are reported. The works of exchanging the recirculating pipings in reactors to 316L pipes withstanding SCC by remote automatic welding to reduce the radiation exposure of workers are introduced. The fully automatic TIG welding system for pipings was developed for the purpose of realizing unmanned welding or the welding that does not require skill, and its constitution and the performance are described. (K.I.)
Automatic query formulations in information retrieval.
Salton, G; Buckley, C; Fox, E A
1983-07-01
Modern information retrieval systems are designed to supply relevant information in response to requests received from the user population. In most retrieval environments the search requests consist of keywords, or index terms, interrelated by appropriate Boolean operators. Since it is difficult for untrained users to generate effective Boolean search requests, trained search intermediaries are normally used to translate original statements of user need into useful Boolean search formulations. Methods are introduced in this study which reduce the role of the search intermediaries by making it possible to generate Boolean search formulations completely automatically from natural language statements provided by the system patrons. Frequency considerations are used automatically to generate appropriate term combinations as well as Boolean connectives relating the terms. Methods are covered to produce automatic query formulations both in a standard Boolean logic system, as well as in an extended Boolean system in which the strict interpretation of the connectives is relaxed. Experimental results are supplied to evaluate the effectiveness of the automatic query formulation process, and methods are described for applying the automatic query formulation process in practice. PMID:10299297
Dasgupta, N; Greenwald, A G
2001-11-01
Two experiments examined whether exposure to pictures of admired and disliked exemplars can reduce automatic preference for White over Black Americans and younger over older people. In Experiment 1, participants were exposed to either admired Black and disliked White individuals, disliked Black and admired White individuals, or nonracial exemplars. Immediately after exemplar exposure and 24 hr later, they completed an Implicit Association Test that assessed automatic racial attitudes and 2 explicit attitude measures. Results revealed that exposure to admired Black and disliked White exemplars significantly weakened automatic pro-White attitudes for 24 hr beyond the treatment but did not affect explicit racial attitudes. Experiment 2 provided a replication using automatic age-related attitudes. Together, these studies provide a strategy that attempts to change the social context and, through it, to reduce automatic prejudice and preference. PMID:11708558
Ruys, Kirsten I; Spears, Russell; Gordijn, Ernestine H; de Vries, Nanne K
2007-08-01
The aim of the present research was to investigate whether unconsciously presented affective information may cause opposite evaluative responses depending on what social category the information originates from. We argue that automatic comparison processes between the self and the unconscious affective information produce this evaluative contrast effect. Consistent with research on automatic behaviour, we propose that when an intergroup context is activated, an automatic comparison to the social self may determine the automatic evaluative responses, at least for highly visible categories (e.g. sex, ethnicity). Contrary to previous research on evaluative priming, we predict automatic contrastive responses to affective information originating from an outgroup category such that the evaluative response to neutral targets is opposite to the valence of the suboptimal primes. Two studies using different intergroup contexts provide support for our hypotheses. PMID:17705936
A versatile automatic TLD system under development
International Nuclear Information System (INIS)
This paper describes an automatic TLD personnel monitoring system intended to replace the filmbadges used by the Radiological Service Unit TNO. The basis of the system is a versatile automatic TLD reader in which the detectors are heated with hot nitrogen gas. After a short description of the reader and some experimental results, a prototype of a TLD badge designed for automatic processing is presented. In this badge - which is waterproof and cannot be opened by the wearer - up to four detectors can be mounted, covered by appropriate filters. A variety of TLD's may be used such as discs, hot-pressed chips and rods. The system is completed with a fingering dosemeter, the detector holder of which can be separated from the ring for other applications (e.g. dosimetry in X-ray diagnostics). (author)
Automatic exploitation system for photographic dosemeters
International Nuclear Information System (INIS)
The Laboratory of Dosimetry Exploitation (LED) has realized an equipment allowing to exploit automatically photographic film dosemeters. This system uses an identification of the films by code-bars and gives the doses measurement with a completely automatic reader. The principle consists in putting in ribbon the emulsions to be exploited and to develop them in a circulation machine. The measurement of the blackening film is realized on a reading plate having fourteen points of reading, in which are circulating the emulsions in ribbon. The exploitation is made with the usual dose calculation method, with special computers codes. A comparison on 2000 dosemeters has shown that the results are the same in manual and automatical methods. This system has been operating since July 1995 by the LED. (N.C.)
Fault injection system for automatic testing system
Institute of Scientific and Technical Information of China (English)
王胜文; 洪炳熔
2003-01-01
Considering the deficiency of the means for confirming the attribution of fault redundancy in the re-search of Automatic Testing System(ATS) , a fault-injection system has been proposed to study fault redundancyof automatic testing system through compurison. By means of a fault-imbeded environmental simulation, thefaults injected at the input level of the software are under test. These faults may induce inherent failure mode,thus bringing about unexpected output, and the anticipated goal of the test is attained. The fault injection con-sists of voltage signal generator, current signal generator and rear drive circuit which are specially developed,and the ATS can work regularly by means of software simulation. The experimental results indicate that the faultinjection system can find the deficiency of the automatic testing software, and identify the preference of fault re-dundancy. On the other hand, some soft deficiency never exposed before can be identified by analyzing the tes-ting results.
Support vector machine for automatic pain recognition
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.
AUTOMATIC WEB SCRAPPING USING VISUAL SELECTORS
Directory of Open Access Journals (Sweden)
Rashmi Bhosale
2015-12-01
Full Text Available The amount of information that is currently vailable on the net grows at a very fast pace, thus web can be considered as the largest knowledge repository ever developed and made available to the public. A web data extraction system is a system that extracts data from web pages automatically. Web data analysis applications such as extracting mutual funds information from a website, extracting opening and closing price of stock daily from a web page and so on involves web data extraction.Early techniques were construcingt wrapper to visit those sites and collect data which is time consuming. Thus a technique called as Automatic Web Scrapping Using Visual Selectors(AWSUVS is proposed. For selected data sections AWSUVS discovers extraction pattern automatically. AWSUVS uses visual cues to identify data records while ignoring noise items such as advertises and navigation bars.
Research on an Intelligent Automatic Turning System
Directory of Open Access Journals (Sweden)
Lichong Huang
2012-12-01
Full Text Available Equipment manufacturing industry is the strategic industries of a country. And its core part is the CNC machine tool. Therefore, enhancing the independent research of relevant technology of CNC machine, especially the open CNC system, is of great significance. This paper presented some key techniques of an Intelligent Automatic Turning System and gave a viable solution for system integration. First of all, the integrated system architecture and the flexible and efficient workflow for perfoming the intelligent automatic turning process is illustrated. Secondly, the innovated methods of the workpiece feature recognition and expression and process planning of the NC machining are put forward. Thirdly, the cutting tool auto-selection and the cutting parameter optimization solution are generated with a integrated inference of rule-based reasoning and case-based reasoning. Finally, the actual machining case based on the developed intelligent automatic turning system proved the presented solutions are valid, practical and efficient.
An Automatic Hierarchical Delay Analysis Tool
Institute of Scientific and Technical Information of China (English)
FaridMheir－El－Saadi; BozenaKaminska
1994-01-01
The performance analysis of VLSI integrated circuits(ICs) with flat tools is slow and even sometimes impossible to complete.Some hierarchical tools have been developed to speed up the analysis of these large ICs.However,these hierarchical tools suffer from a poor interaction with the CAD database and poorly automatized operations.We introduce a general hierarchical framework for performance analysis to solve these problems.The circuit analysis is automatic under the proposed framework.Information that has been automatically abstracted in the hierarchy is kept in database properties along with the topological information.A limited software implementation of the framework,PREDICT,has also been developed to analyze the delay performance.Experimental results show that hierarchical analysis CPU time and memory requirements are low if heuristics are used during the abstraction process.
Automatic Gain Control in Compact Spectrometers.
Protopopov, Vladimir
2016-03-01
An image intensifier installed in the optical path of a compact spectrometer may act not only as a fast gating unit, which is widely used for time-resolved measurements, but also as a variable attenuator-amplifier in a continuous wave mode. This opens the possibility of an automatic gain control, a new feature in spectroscopy. With it, the user is relieved from the necessity to manually adjust signal level at a certain value that it is done automatically by means of an electronic feedback loop. It is even more important that automatic gain control is done without changing exposure time, which is an additional benefit in time-resolved experiments. The concept, algorithm, design considerations, and experimental results are presented. PMID:26810181
Automatic Keywords Extraction for Punjabi Language
Directory of Open Access Journals (Sweden)
Vishal Gupta
2011-09-01
Full Text Available Automatic keywords extraction is the task to identify a small set of words, key phrases, keywords, or key segments from a document that can describe the meaning of the document. Keywords are useful tools as they give the shortest summary of the document. This paper concentrates on Automatic keywords extraction for Punjabi language text. It includes various phases like removing stop words, Identification of Punjabi nouns and noun stemming, Calculation of Term Frequency and Inverse Sentence Frequency (TF-ISF, Punjabi keywords as nouns with high TF-ISF score and title/headline feature for Punjabi text. The extracted keywords are very much helpful in automatic indexing, text summarization, information retrieval, classification, clustering, topic detection and tracking and web searches etc.
Automatic inference of indexing rules for MEDLINE
Directory of Open Access Journals (Sweden)
Shooshan Sonya E
2008-11-01
Full Text Available Abstract Background: Indexing is a crucial step in any information retrieval system. In MEDLINE, a widely used database of the biomedical literature, the indexing process involves the selection of Medical Subject Headings in order to describe the subject matter of articles. The need for automatic tools to assist MEDLINE indexers in this task is growing with the increasing number of publications being added to MEDLINE. Methods: In this paper, we describe the use and the customization of Inductive Logic Programming (ILP to infer indexing rules that may be used to produce automatic indexing recommendations for MEDLINE indexers. Results: Our results show that this original ILP-based approach outperforms manual rules when they exist. In addition, the use of ILP rules also improves the overall performance of the Medical Text Indexer (MTI, a system producing automatic indexing recommendations for MEDLINE. Conclusion: We expect the sets of ILP rules obtained in this experiment to be integrated into MTI.
Oocytes Polar Body Detection for Automatic Enucleation
Directory of Open Access Journals (Sweden)
Di Chen
2016-02-01
Full Text Available Enucleation is a crucial step in cloning. In order to achieve automatic blind enucleation, we should detect the polar body of the oocyte automatically. The conventional polar body detection approaches have low success rate or low efficiency. We propose a polar body detection method based on machine learning in this paper. On one hand, the improved Histogram of Oriented Gradient (HOG algorithm is employed to extract features of polar body images, which will increase success rate. On the other hand, a position prediction method is put forward to narrow the search range of polar body, which will improve efficiency. Experiment results show that the success rate is 96% for various types of polar bodies. Furthermore, the method is applied to an enucleation experiment and improves the degree of automatic enucleation.
Semi-automatic knee cartilage segmentation
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.
Development of automatic laser welding system
International Nuclear Information System (INIS)
Laser are a new production tool for high speed and low distortion welding and applications to automatic welding lines are increasing. IHI has long experience of laser processing for the preservation of nuclear power plants, welding of airplane engines and so on. Moreover, YAG laser oscillators and various kinds of hardware have been developed for laser welding and automation. Combining these welding technologies and laser hardware technologies produce the automatic laser welding system. In this paper, the component technologies are described, including combined optics intended to improve welding stability, laser oscillators, monitoring system, seam tracking system and so on. (author)
Automatic Keyword Extraction from Individual Documents
Energy Technology Data Exchange (ETDEWEB)
Rose, Stuart J.; Engel, David W.; Cramer, Nicholas O.; Cowley, Wendy E.
2010-05-03
This paper introduces a novel and domain-independent method for automatically extracting keywords, as sequences of one or more words, from individual documents. We describe the method’s configuration parameters and algorithm, and present an evaluation on a benchmark corpus of technical abstracts. We also present a method for generating lists of stop words for specific corpora and domains, and evaluate its ability to improve keyword extraction on the benchmark corpus. Finally, we apply our method of automatic keyword extraction to a corpus of news articles and define metrics for characterizing the exclusivity, essentiality, and generality of extracted keywords within a corpus.
Automatic speech recognition a deep learning approach
Yu, Dong
2015-01-01
This book summarizes the recent advancement in the field of automatic speech recognition with a focus on discriminative and hierarchical models. This will be the first automatic speech recognition book to include a comprehensive coverage of recent developments such as conditional random field and deep learning techniques. It presents insights and theoretical foundation of a series of recent models such as conditional random field, semi-Markov and hidden conditional random field, deep neural network, deep belief network, and deep stacking models for sequential learning. It also discusses practical considerations of using these models in both acoustic and language modeling for continuous speech recognition.
The Ballistic Flight of an Automatic Duck
Directory of Open Access Journals (Sweden)
Fabienne Collignon
2012-10-01
Full Text Available This article analyses Jacques de Vaucanson's automatic duck and its successive appearances in Thomas Pynchon's work (both Mason & Dixon and, by extension, Gravity's Rainbow to discuss the correlations between (self- evolving technologies and space age gadgets. The Cold War serves, therefore, as the frame of reference for this article, which is further preoccupied with the geographical positions that automatons or prototype cyborgs occupy: the last part of the essay analyses Walter Benjamin's Arcades Project, where mechanical hens stand at the entrance to dreamworlds. Automatic fowl guard, and usher into being, new technologised worlds.
Automatic malware analysis an emulator based approach
Yin, Heng
2012-01-01
Malicious software (i.e., malware) has become a severe threat to interconnected computer systems for decades and has caused billions of dollars damages each year. A large volume of new malware samples are discovered daily. Even worse, malware is rapidly evolving becoming more sophisticated and evasive to strike against current malware analysis and defense systems. Automatic Malware Analysis presents a virtualized malware analysis framework that addresses common challenges in malware analysis. In regards to this new analysis framework, a series of analysis techniques for automatic malware analy
Automatic emotional expression analysis from eye area
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.
Automatic and strategic processes in advertising effects
DEFF Research Database (Denmark)
Grunert, Klaus G.
1996-01-01
, and can easily be adapted to situational circumstances. Both the perception of advertising and the way advertising influences brand evaluation involves both processes. Automatic processes govern the recognition of advertising stimuli, the relevance decision which determines further higher-level processing...... are at variance with current notions about advertising effects. For example, the att span problem will be relevant only for strategic processes, not for automatic processes, a certain amount of learning can occur with very little conscious effort, and advertising's effect on brand evaluation may be more stable...
Feedback Improvement in Automatic Program Evaluation Systems
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.…
RFID: A Revolution in Automatic Data Recognition
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…
Full-Automatic Parking registration and payment
DEFF Research Database (Denmark)
Agerholm, Niels; Lahrmann, Harry; Jørgensen, Brian;
2014-01-01
As part of ITS Platform North Denmark, a full-automatic GNSS-based parking payment (PP) system was developed (PP app). On the basis of the parking position and parking time, the PP app can determine the price of parking and collect the amount from the car owner’s bank account. The driver is...
Computer Corner: Automatic Differentiation and APL.
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)
Automatic Radiometric Normalization of Multitemporal Satellite Imagery
DEFF Research Database (Denmark)
Canty, Morton J.; Nielsen, Allan Aasbjerg; Schmidt, Michael
2004-01-01
The linear scale invariance of the multivariate alteration detection (MAD) transformation is used to obtain invariant pixels for automatic relative radiometric normalization of time series of multispectral data. Normalization by means of ordinary least squares regression method is compared with n...
Automatically predicting mood from expressed emotions
Katsimerou, C.
2016-01-01
Affect-adaptive systems have the potential to assist users that experience systematically negative moods. This thesis aims at building a platform for predicting automatically a person’s mood from his/her visual expressions. The key word is mood, namely a relatively long-term, stable and diffused aff
MARZ: Manual and automatic redshifting software
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.
Automatic thematic mapping in the EROS program
Edson, D. T.
1972-01-01
A specified approach to the automatic extraction and catographic presentation of thematic data contained in multispectral photographic images is presented. Experimental efforts were directed toward the mapping of open waters, snow and ice, infrared reflective vegetation, and massed works of man. The system must also be able to process data from a wide variety of sources.
Automatic program generation: future of software engineering
Energy Technology Data Exchange (ETDEWEB)
Robinson, J.H.
1979-01-01
At this moment software development is still more of an art than an engineering discipline. Each piece of software is lovingly engineered, nurtured, and presented to the world as a tribute to the writer's skill. When will this change. When will the craftsmanship be removed and the programs be turned out like so many automobiles from an assembly line. Sooner or later it will happen: economic necessities will demand it. With the advent of cheap microcomputers and ever more powerful supercomputers doubling capacity, much more software must be produced. The choices are to double the number of programers, double the efficiency of each programer, or find a way to produce the needed software automatically. Producing software automatically is the only logical choice. How will automatic programing come about. Some of the preliminary actions which need to be done and are being done are to encourage programer plagiarism of existing software through public library mechanisms, produce well understood packages such as compiler automatically, develop languages capable of producing software as output, and learn enough about the whole process of programing to be able to automate it. Clearly, the emphasis must not be on efficiency or size, since ever larger and faster hardware is coming.
Neuroanatomical automatic segmentation in brain cancer patients
D’Haese, P.; Niermann, K; Cmelak, A.; Donnelly, E.; Duay, V.; Li, R; Dawant, B.
2003-01-01
Conformally prescribed radiation therapy for brain cancer requires precisely defining the target treatment area, as well as delineating vital brain structures which must be spared from radiotoxicity. The current clinical practice of manually segmenting brain structures can be complex and exceedingly time consuming. Automatic computeraided segmentation methods have been proposed to increase efficiency and reproducibility in developing radiation treatment plans. Previous studies have establishe...
Portable machine welding head automatically controls arc
Oleksiak, C. E.; Robb, M. A.
1967-01-01
Portable weld tool makes weld repairs out-of-station and on the side opposite the original weld. It provides full automatic control of the arc voltage, current, wire feed, and electrode travel speed in all welding attitudes. The device is readily adaptable to commercially available straight polarity dc weld packs.
State of the Art : Automatic Ontology Matching
Feiyu, Lin
2007-01-01
This report describes the theoretical foundations and relevant background in the domain of automatic ontology matching. It aims to show the range of ontology matching, matching strategies, and an overview of ontology matching systems. The measures for evaluating ontology matching are discussed. This report also summarizes interesting research questions in the field.
Automatic characterization of dynamics in Absence Epilepsy
DEFF Research Database (Denmark)
Petersen, Katrine N. H.; Nielsen, Trine N.; Kjær, Troels W.;
2013-01-01
Dynamics of the spike-wave paroxysms in Childhood Absence Epilepsy (CAE) are automatically characterized using novel approaches. Features are extracted from scalograms formed by Continuous Wavelet Transform (CWT). Detection algorithms are designed to identify an estimate of the temporal development...
Automatic Syntactic Analysis of Free Text.
Schwarz, Christoph
1990-01-01
Discusses problems encountered with the syntactic analysis of free text documents in indexing. Postcoordination and precoordination of terms is discussed, an automatic indexing system call COPSY (context operator syntax) that uses natural language processing techniques is described, and future developments are explained. (60 references) (LRW)
Automatically Locking/Unlocking Orthotic Knee Joint
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.
Development of automatic facilities for ZEPHYR
International Nuclear Information System (INIS)
This concept of remotely controlled facilities for repair and maintenance tasks inside the ZEPHYR vacuum vessel uses a supporting structure to insert various types of mobile automatic devices are guided by an egg-shaped disc which is part of the supporting structure. Considerations of adapting the guiding disc to the vessel contour are included. (orig.)
Experiments in Automatic Library of Congress Classification.
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)
Automatic quality assurance in cutting and machining
International Nuclear Information System (INIS)
Requirements, economics, and possibility of automatic data acquisition and processing are discussed for different production stages. Which of the stages of materials and measuring equipment handling data acquisition, and data processing is to have priority in automation depends on the time requirements of these stages. (orig.)
What is automatized during perceptual categorization?
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. PMID:27232521
Automatic bootstrapping and tracking of object contours.
Chiverton, John; Xie, Xianghua; Mirmehdi, Majid
2012-03-01
A new fully automatic object tracking and segmentation framework is proposed. The framework consists of a motion-based bootstrapping algorithm concurrent to a shape-based active contour. The shape-based active contour uses finite shape memory that is automatically and continuously built from both the bootstrap process and the active-contour object tracker. A scheme is proposed to ensure that the finite shape memory is continuously updated but forgets unnecessary information. Two new ways of automatically extracting shape information from image data given a region of interest are also proposed. Results demonstrate that the bootstrapping stage provides important motion and shape information to the object tracker. This information is found to be essential for good (fully automatic) initialization of the active contour. Further results also demonstrate convergence properties of the content of the finite shape memory and similar object tracking performance in comparison with an object tracker with unlimited shape memory. Tests with an active contour using a fixed-shape prior also demonstrate superior performance for the proposed bootstrapped finite-shape-memory framework and similar performance when compared with a recently proposed active contour that uses an alternative online learning model. PMID:21908256
AUTORED - the JADE automatic data reduction system
International Nuclear Information System (INIS)
The design and implementation of and experience with an automatic data processing system for the reduction of data from the JADE experiment at DESY is described. The central elements are a database and a job submitter which combine powerfully to minimise the need for manual intervention. (author)
Automatic assessment of cardiac perfusion MRI
DEFF Research Database (Denmark)
Ólafsdóttir, Hildur; Stegmann, Mikkel Bille; Larsson, Henrik B.W.
2004-01-01
In this paper, a method based on Active Appearance Models (AAM) is applied for automatic registration of myocardial perfusion MRI. A semi-quantitative perfusion assessment of the registered image sequences is presented. This includes the formation of perfusion maps for three parameters; maximum up...
Automatic Synthesis of Robust and Optimal Controllers
DEFF Research Database (Denmark)
Cassez, Franck; Jessen, Jan Jacob; Larsen, Kim Guldstrand;
2009-01-01
In this paper, we show how to apply recent tools for the automatic synthesis of robust and near-optimal controllers for a real industrial case study. We show how to use three different classes of models and their supporting existing tools, Uppaal-TiGA for synthesis, phaver for verification, and...
Automatic assessment of cardiac perfusion MRI
Ólafsdóttir, Hildur; Stegmann, Mikkel Bille; Larsson, Henrik B. W.
2004-01-01
In this paper, a method based on Active Appearance Models (AAM) is applied for automatic registration of myocardial perfusion MRI. A semi-quantitative perfusion assessment of the registered image sequences is presented. This includes the formation of perfusion maps for three parameters; maximum up-slope, peak and time-to-peak.
Reduction of Dutch Sentences for Automatic Subtitling
Tjong Kim Sang, E.F.; Daelemans, W.; Höthker, A.
2004-01-01
We compare machine learning approaches for sentence length reduction for automatic generation of subtitles for deaf and hearing-impaired people with a method which relies on hand-crafted deletion rules. We describe building the necessary resources for this task: a parallel corpus of examples of news
Automatic visual inspection of hybrid microcircuits
Energy Technology Data Exchange (ETDEWEB)
Hines, R.E.
1980-05-01
An automatic visual inspection system using a minicomputer and a video digitizer was developed for inspecting hybrid microcircuits (HMC) and thin-film networks (TFN). The system performed well in detecting missing components on HMCs and reduced the testing time for each HMC by 75%.
Automatic alignment of hieroglyphs and transliteration
Nederhof, Mark Jan
2009-01-01
Automatic alignment has important applications in philology, facilitating study of texts on the basis of electronic resources produced by different scholars. A simple technique is presented to realise such alignment for Ancient Egyptian hieroglyphic texts and transliteration. Preliminary experiments with the technique are reported, and plans for future work are discussed. Postprint
Learning slip behavior using automatic mechanical supervision
Angelova, Anelia; Matthies, Larry; Helmick, Daniel; Perona, Pietro
2007-01-01
We address the problem of learning terrain traversability properties from visual input, using automatic mechanical supervision collected from sensors onboard an autonomous vehicle. We present a novel probabilistic framework in which the visual information and the mechanical supervision interact to learn particular terrain types and their properties. The proposed method is applied to learning of rover slippage from visual information in a completely auto...
Handwriting Automaticity: The Search for Performance Thresholds
Medwell, Jane; Wray, David
2014-01-01
Evidence is accumulating that handwriting has an important role in written composition. In particular, handwriting automaticity appears to relate to success in composition. This relationship has been little explored in British contexts and we currently have little idea of what threshold performance levels might be. In this paper, we report on two…
Automatically identifying periodic social events from Twitter
Kunneman, F.A.; Bosch, A.P.J. van den
2015-01-01
Many events referred to on Twitter are of a periodic nature, characterized by roughly constant time intervals in between occurrences. Examples are annual music festivals, weekly television programs, and the full moon cycle. We propose a system that can automatically identify periodic events from Twi
Automatic Differentiation and its Program Realization
Czech Academy of Sciences Publication Activity Database
Hartman, J.; Lukšan, Ladislav; Zítko, J.
2009-01-01
Roč. 45, č. 5 (2009), s. 865-883. ISSN 0023-5954 R&D Projects: GA AV ČR IAA1030405 Institutional research plan: CEZ:AV0Z10300504 Keywords : automatic differentiation * modeling languages * systems of optimization Subject RIV: BA - General Mathematics Impact factor: 0.445, year: 2009 http://dml.cz/handle/10338.dmlcz/140037
Automatization and familiarity in repeated checking
Dek, E.C.P.; van den Hout, M.A.; Giele, C.L.; Engelhard, I.M.
2015-01-01
Repetitive, compulsive-like checking of an object leads to reductions in memory confidence, vividness, and detail. Experimental research suggests that this is caused by increased familiarity with perceptual characteristics of the stimulus and automatization of the checking procedure (Dek, van den Ho
Automatic Water Sensor Window Opening System
Percher, Michael
2013-12-05
A system can automatically open at least one window of a vehicle when the vehicle is being submerged in water. The system can include a water collector and a water sensor, and when the water sensor detects water in the water collector, at least one window of the vehicle opens.
Automatic River Network Extraction from LIDAR Data
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.
International Nuclear Information System (INIS)
Respiratory motion in emission tomography leads to reduced image quality. Developed correction methodology has been concentrating on the use of respiratory synchronized acquisitions leading to gated frames. Such frames, however, are of low signal-to-noise ratio as a result of containing reduced statistics. In this work, we describe the implementation of an elastic transformation within a list-mode-based reconstruction for the correction of respiratory motion over the thorax, allowing the use of all data available throughout a respiratory motion average acquisition. The developed algorithm was evaluated using datasets of the NCAT phantom generated at different points throughout the respiratory cycle. List-mode-data-based PET-simulated frames were subsequently produced by combining the NCAT datasets with Monte Carlo simulation. A non-rigid registration algorithm based on B-spline basis functions was employed to derive transformation parameters accounting for the respiratory motion using the NCAT dynamic CT images. The displacement matrices derived were subsequently applied during the image reconstruction of the original emission list mode data. Two different implementations for the incorporation of the elastic transformations within the one-pass list mode EM (OPL-EM) algorithm were developed and evaluated. The corrected images were compared with those produced using an affine transformation of list mode data prior to reconstruction, as well as with uncorrected respiratory motion average images. Results demonstrate that although both correction techniques considered lead to significant improvements in accounting for respiratory motion artefacts in the lung fields, the elastic-transformation-based correction leads to a more uniform improvement across the lungs for different lesion sizes and locations
PORE-SCALE SIMULATION OF FLUID FLOW IN PACKED-BED REACTORS VIA RIGID-BODY SIMULATIONS AND CFD
Icardi, Matteo; Marchisio, Daniele,; Boccardo, Gianluca
2014-01-01
The problem of fluid flow in porous media is of paramount importance in the process, oil and metallurgical industries, since it is involved in the extraction of minerals and oil, in aquifer dynamics, as well as chemical reactions carried out in fixed bed catalytic reactors. Its CFD simulation is particularly interesting, as it offers the possibility of reducing the extent of costly experimental investigations, but presents a number of technical challenges. One of the main issues is the genera...
Czech Academy of Sciences Publication Activity Database
Ducomet, B.; Nečasová, Šárka
Prague : Institute of Math ematics AS CR, 2012 - (Brandts, J.; Chleboun, J.; Korotov, S.; Segeth, K.; Šístek, J.; Vejchodský, T.), s. 83-98 ISBN 978-80-85823-60-8. [Applications of Math ematics 2012. Prague (CZ), 02.05.2012-05.05.2012] R&D Projects: GA ČR(CZ) GAP201/11/1304 Institutional support: RVO:67985840 Keywords : compressible viscous fluid * motion Subject RIV: BA - General Math ematics http://www. math .cas.cz/~am2012/proceedings/contributions/ducomet.pdf
Point vortex dynamics as zero-radius limit of the motion of a rigid body in an irrotational fluid
Glass, Olivier; Munnier, Alexandre; Sueur, Franck
2016-01-01
The vortex point system is usually considered as an idealized model where thevorticity of an ideal incompressible two-dimensional fluid is concentrated in afinite number of moving points. In the case of a single vortex in an otherwise irrotational ideal fluid occupying a bounded and simply-connected two-dimensional domain the motion is given by the so-called Kirchhoff-Routh velocity which depends only on the domain.The main result of this paper establishes that this dynamics canalso be obtain...
DEFF Research Database (Denmark)
de Vaal, Jacobus B.; Hansen, Martin Otto Laver; Moan, Torgeir
2014-01-01
experienced by a floating wind turbine. After discussing the simplified model in detail, comparisons are made to a state of the art free wake vortex code, using test cases with prescribed platform motion. It is found that the simplified model compares favourably with a more advanced numerical model, and...
International Nuclear Information System (INIS)
Adhering to the lore that vorticity is a critical ingredient of fluid turbulence, a triad of coupled helicity (vorticity) states of the incompressible Navier-Stokes fluid are followed. Effects of the remaining states of the fluid on the triad are then modeled as a simple driving term. Numerical solution of the equations yield attractors that seem strange and chaotic. This suggests that the unpredictability of nonlinear fluid dynamics (i.e., turbulence) may be traced back to the most primordial structure of the Navier-Stokes equation; namely, the driven triadic interaction. copyright 1996 The American Physical Society
International Nuclear Information System (INIS)
A new method for the rapid generation of high resolution bicrystal LACBED images is described, which uses reciprocity to generate the second-crystal transmission function for a specific doubly-transmitted beam. As a result, sets of bright-field or specific dark-field LACBED images can readily be generated for sets inter-crystal displacements, to allow comparison with experimental results. In Part I we describe results obtained for pure translations between bi-crystals pairs, while in Part II we describe the method for bi-crystals incorporating relative rotations as well as translations. It is envisaged that this technique will be useful for the body semi-conductor crystal pair interfaces, and metal-alloy grain boundaries, in particular. (authors). 16 refs., 6 figs
Qiu-Yu Lu; Wei Hu; Le Zheng; Yong Min; Miao Li; Xiao-Ping Li; Wei-Chun Ge; Zhi-Ming Wang
2012-01-01
Automatic Generation Control (AGC) and Automatic Voltage Control (AVC) are key approaches to frequency and voltage regulation in power systems. However, based on the assumption of decoupling of active and reactive power control, the existing AGC and AVC systems work independently without any coordination. In this paper, a concept and method of hybrid control is introduced to set up an Integrated Coordinated Optimization Control (ICOC) system for AGC and AVC. Concerning the diversity of contro...
An automatic measuring system of internal friction at low frequency
International Nuclear Information System (INIS)
An inverted torsion pendulum is automatized by means of Tectanel electronic system. Internal friction and the period of vibration are measured fully automatically as a function of temperature and the data obtained are analysed with a computer. (Author)
Using automatic programming for simulating reliability network models
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.
Abbreviation definition identification based on automatic precision estimates
Kim Won; Comeau Donald C; Sohn Sunghwan; Wilbur W John
2008-01-01
Abstract Background The rapid growth of biomedical literature presents challenges for automatic text processing, and one of the challenges is abbreviation identification. The presence of unrecognized abbreviations in text hinders indexing algorithms and adversely affects information retrieval and extraction. Automatic abbreviation definition identification can help resolve these issues. However, abbreviations and their definitions identified by an automatic process are of uncertain validity. ...
30 CFR 75.1403-4 - Criteria-Automatic elevators.
2010-07-01
... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Criteria-Automatic elevators. 75.1403-4 Section... Criteria—Automatic elevators. (a) The doors of automatic elevators should be equipped with interlocking switches so arranged that the elevator car will be immovable while any door is opened or unlocked,...
The ‘Continuing Misfortune’ of Automatism in Early Surrealism
Directory of Open Access Journals (Sweden)
Tessel M. Bauduin
2015-09-01
Full Text Available In the 1924 Manifesto of Surrealism surrealist leader André Breton (1896-1966 defined Surrealism as ‘psychic automatism in its pure state,’ positioning ‘psychic automatism’ as both a concept and a technique. This definition followed upon an intense period of experimentation with various forms of automatism among the proto-surrealist group; predominantly automatic writing, but also induced dream states. This article explores how surrealist ‘psychic automatism’ functioned as a mechanism for communication, or the expression of thought as directly as possible through the unconscious, in the first two decades of Surrealism. It touches upon automatic writing, hysteria as an automatic bodily performance of the unconscious, dreaming and the experimentation with induced dream states, and automatic drawing and other visual arts-techniques that could be executed more or less automatically as well. For all that the surrealists reinvented automatism for their own poetic, artistic and revolutionary aims, the automatic techniques were primarily drawn from contemporary Spiritualism, psychical research and experimentation with mediums, and the article teases out the connections to mediumistic automatism. It is demonstrated how the surrealists effectively and successfully divested automatism of all things spiritual. It furthermore becomes clear that despite various mishaps, automatism in many forms was a very successful creative technique within Surrealism.
Directory of Open Access Journals (Sweden)
David J Clark
2015-05-01
Full Text Available 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.
Towards automatic classification of all WISE sources
Kurcz, Agnieszka; Solarz, Aleksandra; Krupa, Magdalena; Pollo, Agnieszka; Małek, Katarzyna
2016-01-01
The WISE satellite has detected hundreds of millions sources over the entire sky. Classifying them reliably is however a challenging task due to degeneracies in WISE multicolour space and low levels of detection in its two longest-wavelength bandpasses. Here we aim at obtaining comprehensive and reliable star, galaxy and quasar catalogues based on automatic source classification in full-sky WISE data. This means that the final classification will employ only parameters available from WISE itself, in particular those reliably measured for a majority of sources. For the automatic classification we applied the support vector machines (SVM) algorithm, which requires a training sample with relevant classes already identified, and we chose to use the SDSS spectroscopic dataset for that purpose. By calibrating the classifier on the test data drawn from SDSS, we first established that a polynomial kernel is preferred over a radial one for this particular dataset. Next, using three classification parameters (W1 magnit...
Development of an automatic pipeline scanning system
Energy Technology Data Exchange (ETDEWEB)
Kim, Jae H.; Lee, Jae C.; Moon, Soon S.; Eom, Heung S.; Choi, Yu R
1999-11-01
Pressure pipe inspection in nuclear power plants is one of the mandatory regulation items. Comparing to manual ultrasonic inspection, automatic inspection has the benefits of more accurate and reliable inspection results and reduction of radiation disposal. final object of this project is to develop an automatic pipeline inspection system of pressure pipe welds in nuclear power plants. We developed a pipeline scanning robot with four magnetic wheels and 2-axis manipulator for controlling ultrasonic transducers, and developed the robot control computer which controls the robot to navigate along inspection path exactly. We expect our system can contribute to reduction of inspection time, performance enhancement, and effective management of inspection results. The system developed by this project can be practically used for inspection works after field tests. (author)
Towards Automatic Decentralized Control Structure Selection
DEFF Research Database (Denmark)
Jørgensen, John Bagterp; Jørgensen, Sten Bay
2000-01-01
A subtask in integration of design and control of chemical processes is the selection of a control structure. Automating the selection of the control structure enables sequential integration of process and control design. As soon as the process is specified or computed, a structure for...... decentralized control is determined automatically, and the resulting decentralized control structure is automatically tuned using standard techniques. Dynamic simulation of the resulting process system gives immediate feedback to the process design engineer regarding practical operability of the process. The...... control structure selection problem is formulated as a special MILP employing cost coefficients which are computed using Parseval's theorem combined with RGA and IMC concepts. This approach enables selection and tuning of large-scale plant-wide decentralized controllers through efficient combination of...
Towards Automatic Decentralized Control Structure Selection
DEFF Research Database (Denmark)
A subtask in integration of design and control of chemical processes is the selection of a control structure. Automating the selection of the control structure enables sequential integration of process and controld esign. As soon as the process is specified or computed, a structure for...... decentralized control is determined automatically, and the resulting decentralized control structure is automatically tuned using standard techniques. Dynamic simulation of the resulting process system gives immediate feedback to the process design engineer regarding practical operability of the process. The...... control structure selection problem is formulated as a special MILP employing cost coefficients which are computed using Parseval's theorem combined with RGA and IMC concepts. This approach enables selection and tuning of large-scale plant-wide decentralized controllers through efficient combination of...
The Lick-Gaertner automatic measuring system
Vasilevskis, S.; Popov, W. A.
1971-01-01
The Lick-Gaertner automatic equipment has been designed mainly for the measurement of stellar proper motions with reference to galaxies, and consists of two main components: the survey machine and the automatic measuring engine. The survey machine is used for initial inspection and selection of objects for subsequent measurement. Two plates, up to 17 x 17 inches each, are surveyed simultaneously by means of projection on a screen. The approximate positions of objects selected are measured by two optical screws: helical lines cut through an aluminum coating on glass cylinders. These approximate coordinates to a precision of the order of 0.03mm are transmitted to a card punch by encoders connected with the cylinders.
Automatic classification of defects in weld pipe
International Nuclear Information System (INIS)
With the advancement of computer imaging technology, the image on hard radiographic film can be digitized and stored in a computer and the manual process of defect recognition and classification may be replace by the computer. In this paper a computerized method for automatic detection and classification of common defects in film radiography of weld pipe is described. The detection and classification processes consist of automatic selection of interest area on the image and then classify common defects using image processing and special algorithms. Analysis of the attributes of each defect such as area, size, shape and orientation are carried out by the feature analysis process. These attributes reveal the type of each defect. These methods of defect classification result in high success rate. Our experience showed that sharp film images produced better results
Automatic breast density classification using neural network
International Nuclear Information System (INIS)
According to studies, the risk of breast cancer directly associated with breast density. Many researches are done on automatic diagnosis of breast density using mammography. In the current study, artifacts of mammograms are removed by using image processing techniques and by using the method presented in this study, including the diagnosis of points of the pectoral muscle edges and estimating them using regression techniques, pectoral muscle is detected with high accuracy in mammography and breast tissue is fully automatically extracted. In order to classify mammography images into three categories: Fatty, Glandular, Dense, a feature based on difference of gray-levels of hard tissue and soft tissue in mammograms has been used addition to the statistical features and a neural network classifier with a hidden layer. Image database used in this research is the mini-MIAS database and the maximum accuracy of system in classifying images has been reported 97.66% with 8 hidden layers in neural network
Fully Automatic Expression-Invariant Face Correspondence
Salazar, Augusto; Shu, Chang; Prieto, Flavio
2012-01-01
We consider the problem of computing accurate point-to-point correspondences among a set of human face scans with varying expressions. Our fully automatic approach does not require any manually placed markers on the scan. Instead, the approach learns the locations of a set of landmarks present in a database and uses this knowledge to automatically predict the locations of these landmarks on a newly available scan. The predicted landmarks are then used to compute point-to-point correspondences between a template model and the newly available scan. To accurately fit the expression of the template to the expression of the scan, we use as template a blendshape model. Our algorithm was tested on a database of human faces of different ethnic groups with strongly varying expressions. Experimental results show that the obtained point-to-point correspondence is both highly accurate and consistent for most of the tested 3D face models.
Semi-automatic drawings surveying system
International Nuclear Information System (INIS)
A system for the semi-automatic survey of drawings is presented. Its design has been oriented to the reduction of the stored information required for the drawing reproduction. This equipment consists mainly of a plotter driven by a micro-computer, but the pen of the plotter is replaced by a circular photodiode array. Line drawings are first viewed as a concatenation of vectors, with constant angle between the two vectors, and then divided in arcs of circles and line segments. A dynamic analysis of line intersections with the circular sensor permits to identify starting points and end points in a line, for the purpose of automatically following connected lines in drawing. The advantage of the method described is that precision practically depends only on the plotter performance, the sensor resolution being only considered for the thickness of strokes and the distance between two strokes. (author)
Automatic Classification of Attacks on IP Telephony
Directory of Open Access Journals (Sweden)
Jakub Safarik
2013-01-01
Full Text Available This article proposes an algorithm for automatic analysis of attack data in IP telephony network with a neural network. Data for the analysis is gathered from variable monitoring application running in the network. These monitoring systems are a typical part of nowadays network. Information from them is usually used after attack. It is possible to use an automatic classification of IP telephony attacks for nearly real-time classification and counter attack or mitigation of potential attacks. The classification use proposed neural network, and the article covers design of a neural network and its practical implementation. It contains also methods for neural network learning and data gathering functions from honeypot application.
Retrotrapezoid nucleus, respiratory chemosensitivity and breathing automaticity
Guyenet, Patrice G.; Bayliss, Douglas A.; Stornetta, Ruth L.; Fortuna, Michal G.; Abbott, Stephen B.; Depuy, Seth D.
2009-01-01
SUMMARY Breathing automaticity and CO2 regulation are inseparable neural processes. The retrotrapezoid nucleus (RTN), a group of glutamatergic neurons that express the transcription factor Phox2b, may be a crucial nodal point through which breathing automaticity is regulated to maintain CO2 constant. This review updates the analysis presented in prior publications. Additional evidence that RTN neurons have central respiratory chemoreceptor properties is presented but this is only one of many factors that determine their activity. The RTN is also regulated by powerful inputs from the carotid bodies and, at least in the adult, by many other synaptic inputs. We also analyze how RTN neurons may control the activity of the downstream central respiratory pattern generator. Specifically, we review the evidence which suggests that RTN neurons a) innervate the entire ventral respiratory column, and b) control both inspiration and expiration. Finally, we argue that the RTN neurons are the adult form of the parafacial respiratory group in neonate rats. PMID:19712903
Testing Forms in Web Applications Automatically
Institute of Scientific and Technical Information of China (English)
XU Lei; XU Baowen
2006-01-01
Forms enhance both the dynamic and interactive abilities of Web applications and the system complexity. And it is especially important to test forms completely and thoroughly. Therefore, this paper discusses how to carry out the form testing by different methods in the related testing phases. Namely, at first, automatically abstracting forms in the Web pages by parsing the HTML documents; then, obtaining the testing data with a certain strategies, such as by requirement specifications, by mining users' before input information or by recording mechanism; and next executing the testing actions automatically due to the well-formed test cases; finally, a case study is given to illustrate the convenient and effective of these methods.
Automatic differentiation and lattice function matching
International Nuclear Information System (INIS)
Although popularized in accelerator physics for the calculation of the Taylor coefficients of phase space maps, automatic differentiation is a generic and powerful technique applicable to any problem where fast and accurate evaluation of (usually first order) derivatives is needed. Problems requiring the evaluation of sensitivities with respect to parameters of a model or the minimization of an error function permeate applications in accelerator physics. The advent of languages with built-in support for operator overloading-such as C++-results in greatly simplified syntax and highly maintainable software. To illustrate this point in practice, we apply automatic differentiation techniques to linear lattice function matching, an important problem encountered in the context of designing insertions or transfer lines between accelerators
Automatic modulation recognition of communication signals
Azzouz, Elsayed Elsayed
1996-01-01
Automatic modulation recognition is a rapidly evolving area of signal analysis. In recent years, interest from the academic and military research institutes has focused around the research and development of modulation recognition algorithms. Any communication intelligence (COMINT) system comprises three main blocks: receiver front-end, modulation recogniser and output stage. Considerable work has been done in the area of receiver front-ends. The work at the output stage is concerned with information extraction, recording and exploitation and begins with signal demodulation, that requires accurate knowledge about the signal modulation type. There are, however, two main reasons for knowing the current modulation type of a signal; to preserve the signal information content and to decide upon the suitable counter action, such as jamming. Automatic Modulation Recognition of Communications Signals describes in depth this modulation recognition process. Drawing on several years of research, the authors provide a cr...
Automatic Cooking Robot for Chinese Dishes
Institute of Scientific and Technical Information of China (English)
GEN Kai-ping; XU Yu; ZHAN Jing-wen
2009-01-01
Until now, most of the kitchen works are done manually, which often make people bored and suffer from cooking oil smoke pollution. With the development of the robotic technology, it becomes more and more urgent for the appearance of the automatic cooking machines that can substitute man for most of those works. With this aim in mind, in this paper, a kind of automatic cooking robot is presented, which mainly consists of five parts: the wok mechanism, the stirring-fry and dispersing mechanism, the feeding mechanism, fire control system and the assistant ingredients processing mechanism. Experiment results have proved that the robot has achieved the goal with respect to appearance, smell, and taste of the dishes cooked by the robot, according to the master cook's view.
Automatic Phonetic Transcription for Danish Speech Recognition
DEFF Research Database (Denmark)
Kirkedal, Andreas Søeborg
to acquire and expensive to create. For languages with productive compounding or agglutinative languages like German and Finnish, respectively, phonetic dictionaries are also hard to maintain. For this reason, automatic phonetic transcription tools have been produced for many languages. The quality...... of automatic phonetic transcriptions vary greatly with respect to language and transcription strategy. For some languages where the difference between the graphemic and phonetic representations are small, graphemic transcriptions can be used to create ASR systems with acceptable performance. In other languages......, syllabication, stød and several other suprasegmental features (Kirkedal, 2013). Simplifying the transcriptions by filtering out the symbols for suprasegmental features in a post-processing step produces a format that is suitable for ASR purposes. eSpeak is an open source speech synthesizer originally created...
Automatic document navigation for digital content remastering
Lin, Xiaofan; Simske, Steven J.
2003-12-01
This paper presents a novel method of automatically adding navigation capabilities to re-mastered electronic books. We first analyze the need for a generic and robust system to automatically construct navigation links into re-mastered books. We then introduce the core algorithm based on text matching for building the links. The proposed method utilizes the tree-structured dictionary and directional graph of the table of contents to efficiently conduct the text matching. Information fusion further increases the robustness of the algorithm. The experimental results on the MIT Press digital library project are discussed and the key functional features of the system are illustrated. We have also investigated how the quality of the OCR engine affects the linking algorithm. In addition, the analogy between this work and Web link mining has been pointed out.
Automatic analysis and classification of surface electromyography.
Abou-Chadi, F E; Nashar, A; Saad, M
2001-01-01
In this paper, parametric modeling of surface electromyography (EMG) algorithms that facilitates automatic SEMG feature extraction and artificial neural networks (ANN) are combined for providing an integrated system for the automatic analysis and diagnosis of myopathic disorders. Three paradigms of ANN were investigated: the multilayer backpropagation algorithm, the self-organizing feature map algorithm and a probabilistic neural network model. The performance of the three classifiers was compared with that of the old Fisher linear discriminant (FLD) classifiers. The results have shown that the three ANN models give higher performance. The percentage of correct classification reaches 90%. Poorer diagnostic performance was obtained from the FLD classifier. The system presented here indicates that surface EMG, when properly processed, can be used to provide the physician with a diagnostic assist device. PMID:11556501
Channel selection for automatic seizure detection
DEFF Research Database (Denmark)
Duun-Henriksen, Jonas; Kjaer, Troels Wesenberg; Madsen, Rasmus Elsborg; Remvig, Line Sofie; Thomsen, Carsten Eckhart; Sørensen, Helge Bjarup Dissing
2012-01-01
Objective: To investigate the performance of epileptic seizure detection using only a few of the recorded EEG channels and the ability of software to select these channels compared with a neurophysiologist. Methods: Fifty-nine seizures and 1419 h of interictal EEG are used for training and testing...... of an automatic channel selection method. The characteristics of the seizures are extracted by the use of a wavelet analysis and classified by a support vector machine. The best channel selection method is based upon maximum variance during the seizure. Results: Using only three channels, a seizure...... recorded directly on the epileptic focus. Conclusions: Based on our dataset, automatic seizure detection can be done using only three EEG channels without loss of performance. These channels should be selected based on maximum variance and not, as often done, using the focal channels. Significance: With...
Automatic transformations in the inference process
Energy Technology Data Exchange (ETDEWEB)
Veroff, R. L.
1980-07-01
A technique for incorporating automatic transformations into processes such as the application of inference rules, subsumption, and demodulation provides a mechanism for improving search strategies for theorem proving problems arising from the field of program verification. The incorporation of automatic transformations into the inference process can alter the search space for a given problem, and is particularly useful for problems having broad rather than deep proofs. The technique can also be used to permit the generation of inferences that might otherwise be blocked and to build some commutativity or associativity into the unification process. Appropriate choice of transformations, and new literal clashing and unification algorithms for applying them, showed significant improvement on several real problems according to several distinct criteria. 22 references, 1 figure.
11th Portuguese Conference on Automatic Control
Matos, Aníbal; Veiga, Germano
2015-01-01
During the last 20 years the Portuguese association of automatic control, Associação Portuguesa de Controlo Automático, with the sponsorship of IFAC have established the CONTROLO conference as a reference international forum where an effective exchange of knowledge and experience amongst researchers active in various theoretical and applied areas of systems and control can take place, always including considerable space for promoting new technical applications and developments, real-world challenges and success stories. In this 11th edition the CONTROLO conference evolved by introducing two strategic partnerships with Spanish and Brazilian associations in automatic control, Comité Español de Automática and Sociedade Brasileira de Automatica, respectively.
Automatic traveltime picking using instantaneous traveltime
Saragiotis, Christos
2013-02-08
Event picking is used in many steps of seismic processing. We present an automatic event picking method that is based on a new attribute of seismic signals, instantaneous traveltime. The calculation of the instantaneous traveltime consists of two separate but interrelated stages. First, a trace is mapped onto the time-frequency domain. Then the time-frequency representation is mapped back onto the time domain by an appropriate operation. The computed instantaneous traveltime equals the recording time at those instances at which there is a seismic event, a feature that is used to pick the events. We analyzed the concept of the instantaneous traveltime and demonstrated the application of our automatic picking method on dynamite and Vibroseis field data.
TMB: Automatic differentiation and laplace approximation
DEFF Research Database (Denmark)
Kristensen, Kasper; Nielsen, Anders; Berg, Casper Willestofte;
2016-01-01
TMB is an open source R package that enables quick implementation of complex nonlinear random effects (latent variable) models in a manner similar to the established AD Model Builder package (ADMB, http://admb-project.org/; Fournier et al. 2011). In addition, it offers easy access to parallel...... computations. The user defines the joint likelihood for the data and the random effects as a C++ template function, while all the other operations are done in R; e.g., reading in the data. The package evaluates and maximizes the Laplace approximation of the marginal likelihood where the random effects are...... automatically integrated out. This approximation, and its derivatives, are obtained using automatic differentiation (up to order three) of the joint likelihood. The computations are designed to be fast for problems with many random effects (approximate to 10(6)) and parameters (approximate to 10...
An Incremental Approach to Automatic Algorithm Design
Institute of Scientific and Technical Information of China (English)
LUAN Shangmin; LI Wei
1999-01-01
This paper presents an incrementalapproach to automatic algorithm design, which can be described byalgebraic specifications precisely and conveniently. The definitions ofselection operator and extension operator which can be defined bystrategy relations and transformations are given in order to model theprocess of finding the solution of a problem. Also discussed is itsobject-oriented implementation. The functional specification and thedesign specification for an algorithm are given in one framework so thatthe correctness of the algorithm can be easily proved.
An Automatic Indirect Immunofluorescence Cell Segmentation System
2014-01-01
Indirect immunofluorescence (IIF) with HEp-2 cells has been used for the detection of antinuclear autoantibodies (ANA) in systemic autoimmune diseases. The ANA testing allows us to scan a broad range of autoantibody entities and to describe them by distinct fluorescence patterns. Automatic inspection for fluorescence patterns in an IIF image can assist physicians, without relevant experience, in making correct diagnosis. How to segment the cells from an IIF image is essential in developing an...
Automatically Generating Game Tactics through Evolutionary Learning
Ponsen, Marc; Munoz-Avila, Hector; Spronck, Pieter; Aha, David W.
2006-01-01
The decision-making process of computer-controlled opponents in video games is called game AI. Adaptive game AI can improve the entertainment value of games by allowing computer-controlled opponents to ix weaknesses automatically in the game AI and to respond to changes in human-player tactics. Dynamic scripting is a reinforcement learning approach to adaptive game AI that learns, during gameplay, which game tactics an opponent should select to play effectively. In previous work, the tactics ...
Automatic Status Logger For a Gas Turbine
JONAS, Susanne
2007-01-01
The Company Siemens Industrial Turbo Machinery AB manufactures and launches in operation among other things gas turbines, steam turbines, compressors, turn-key power plants and carries out service for components for heat and power production. Siemens also performs research and development, marketing, sales and installations of turbines and completes power plants, service and refurbish. Our thesis for the engineering degree is to develop an automatic status log which will be used as a tool to ...
Automatic Algorithm Selection for Complex Simulation Problems
Ewald, Roland
2012-01-01
To select the most suitable simulation algorithm for a given task is often difficult. This is due to intricate interactions between model features, implementation details, and runtime environment, which may strongly affect the overall performance. An automated selection of simulation algorithms supports users in setting up simulation experiments without demanding expert knowledge on simulation. Roland Ewald analyzes and discusses existing approaches to solve the algorithm selection problem in the context of simulation. He introduces a framework for automatic simulation algorithm selection and
Automatic Extraction of JPF Options and Documentation
Luks, Wojciech; Tkachuk, Oksana; Buschnell, David
2011-01-01
Documenting existing Java PathFinder (JPF) projects or developing new extensions is a challenging task. JPF provides a platform for creating new extensions and relies on key-value properties for their configuration. Keeping track of all possible options and extension mechanisms in JPF can be difficult. This paper presents jpf-autodoc-options, a tool that automatically extracts JPF projects options and other documentation-related information, which can greatly help both JPF users and developers of JPF extensions.
Automatic modulation classification principles, algorithms and applications
Zhu, Zhechen
2014-01-01
Automatic Modulation Classification (AMC) has been a key technology in many military, security, and civilian telecommunication applications for decades. In military and security applications, modulation often serves as another level of encryption; in modern civilian applications, multiple modulation types can be employed by a signal transmitter to control the data rate and link reliability. This book offers comprehensive documentation of AMC models, algorithms and implementations for successful modulation recognition. It provides an invaluable theoretical and numerical comparison of AMC algo
Automatic Discovery of Word Semantic Relations
Dias, Gael; Moraliyski, Rumen; Cordeiro, Joao; Doucet, Antoine; Ahonen-Myka, Helena
2010-01-01
In this paper, we propose an unsupervised methodology to automatically discover pairs of semantically related words by highlighting their local environment and evaluating their semantic similarity in local and global semantic spaces. This proposal di®ers from previous research as it tries to take the best of two different methodologies i.e. semantic space models and information extraction models. It can be applied to extract close semantic relations, it limits the search space and...
Feature detection with automatic scale selection
Lindeberg, Tony
1998-01-01
The fact that objects in the world appear in different ways depending on the scale of observation has important implications if one aims at describing them. It shows that the notion of scale is of utmost importance when processing unknown measurement data by automatic methods. Whereas scale-space representation provides a well-founded framework for dealing with this issue by representing image structures at different scales, traditional scale-space theory does not address the problem of how t...
Automatic targeting of plasma spray gun
International Nuclear Information System (INIS)
A means for monitoring the material portion in the flame of a plasma spray gun during spraying operations is described. A collimated detector, sensitive to certain wavelengths of light emission, is used to locate the centroid of the material with each pass of the gun. The response from the detector is then relayed to the gun controller to be used to automatically realign the gun
IR Thermometer with Automatic Emissivity Correction
Dobesch, A.; POLIAK,J
2013-01-01
The paper describes the design and implementation of an infrared (IR) thermometer with automatic emissivity correction. The temperature measurement is carried out by the simple digital thermopile sensor MLX90614. The emissivity correction is based on benefits of diffuse reflecting materials and it uses an IR laser diode in conjunction with a selective amplifier. Moreover, the paper includes the design of the control interface with a graphics LCD. Furthermore, this paper describes the power su...
Automatic Transmission Power Flow Matrix Representation
Öun, Martin
2014-01-01
The project has worked with the function and structure of epicyclical automatic transmissions. The goal of the project has been to find a mathematical way of representing the transmissions setup and possible power flows. Furthermore the project has included the generation of all theoretically possible matrix representations of two simple planetary gear sets in MATLAB as the base for a future optimization model. The result of the project is a large quantity of matrix representations of the two...
ANALYSIS METHOD OF AUTOMATIC PLANETARY TRANSMISSION KINEMATICS
Józef DREWNIAK; Stanisław ZAWIŚLAK; Wieczorek, Andrzej
2014-01-01
In the present paper, planetary automatic transmission is modeled by means of contour graphs. The goals of modeling could be versatile: ratio calculating via algorithmic equation generation, analysis of velocity and accelerations. The exemplary gears running are analyzed, several drives/gears are consecutively taken into account discussing functional schemes, assigned contour graphs and generated system of equations and their solutions. The advantages of the method are: algorithmic approach, ...
Automatic Knowledge Base Evolution by Learning Instances
Kim, Sundong
2016-01-01
Knowledge base is the way to store structured and unstructured data throughout the web. Since the size of the web is increasing rapidly, there are huge needs to structure the knowledge in a fully automated way. However fully-automated knowledge-base evolution on the Semantic Web is a major challenges, although there are many ontology evolution techniques available. Therefore learning ontology automatically can contribute to the semantic web society significantly. In this paper, we propose ful...
Automatic generation of multilingual sports summaries
Hasan, Fahim Muhammad
2011-01-01
Natural Language Generation is a subfield of Natural Language Processing, which is concerned with automatically creating human readable text from non-linguistic forms of information. A template-based approach to Natural Language Generation utilizes base formats for different types of sentences, which are subsequently transformed to create the final readable forms of the output. In this thesis, we investigate the suitability of a template-based approach to multilingual Natural Language Generat...
Automatic Induction of Rule Based Text Categorization
D.Maghesh Kumar
2010-01-01
The automated categorization of texts into predefined categories has witnessed a booming interest in the last 10 years, due to the increased availability of documents in digital form and the ensuingneed to organize them. In the research community the dominant approach to this problem is based on machine learning techniques: a general inductive process automatically builds a classifier by learning, from a set of preclassified documents, the characteristics of the categories. This paper describ...
Automatic kelvin probe compatible with ultrahigh vacuum
Baikie, I.D.; Werf, van der, M.J.; Oerbekke, H.; Broeze, J.; Silfhout, van, A.
1989-01-01
This article describes a new type of in situ ultrahigh‐vacuum compatible kelvin probe based on a voice‐coil driving mechanism. This design exhibits several advantages over conventional mechanical feed‐through and (in situ) piezoelectric devices in regard to the possibility of multiple probe geometry, flexibility of probe geometry, amplitude of oscillation, and pure parallel vibration. Automatic setup and constant spacing features are achieved using a digital‐to‐analog converter (DAC) steered ...
Using Protege for Automatic Ontology Instantiation
Alani, Harith; Kim, Sanghee; Millard, David E.; Weal, Mark J.; Hall, Wendy; Lewis, Paul H.; Shadbolt, Nigel
2004-01-01
This paper gives an overview on the use of Protégé in the Artequakt system, which integrated Protégé with a set of natural language tools to automatically extract knowledge about artists from web documents and instantiate a given ontology. Protégé was also linked to structured templates that generate documents from the knowledge fragments it maintains.
Automatic liquid-liquid extraction system
International Nuclear Information System (INIS)
This invention concerns an automatic liquid-liquid extraction system ensuring great reproducibility on a number of samples, stirring and decanting of the two liquid phases, then the quantitative removal of the entire liquid phase present in the extraction vessel at the end of the operation. This type of system has many applications, particularly in carrying out analytical processes comprising a stage for the extraction, by means of an appropriate solvent, of certain components of the sample under analysis
Automatic location of short circuit faults
Energy Technology Data Exchange (ETDEWEB)
Lehtonen, M. [VTT Energy, Espoo (Finland); Hakola, T.; Antila, E. [ABB Power Oy (Finland); Seppaenen, M. [North-Carelian Power Company (Finland)
1998-08-01
In this chapter, the automatic location of short circuit faults on medium voltage distribution lines, based on the integration of computer systems of medium voltage distribution network automation is discussed. First the distribution data management systems and their interface with the substation telecontrol, or SCADA systems, is studied. Then the integration of substation telecontrol system and computerized relay protection is discussed. Finally, the implementation of the fault location system is presented and the practical experience with the system is discussed
The Automatic Statistician: A Relational Perspective
Hwang, Yunseong; Tong, Anh; Choi, Jaesik
2015-01-01
Gaussian Processes (GPs) provide a general and analytically tractable way of modeling complex time-varying, nonparametric functions. The Automatic Bayesian Covariance Discovery (ABCD) system constructs natural-language description of time-series data by treating unknown time-series data nonparametrically using GP with a composite covariance kernel function. Unfortunately, learning a composite covariance kernel with a single time-series data set often results in less informative kernel that ma...
Automatic summary evaluation based on text grammars
Branny, Emilia
2007-01-01
In this paper, I describe a method for evaluating automatically generated text summaries. The method is inspired by research in text grammars by Teun Van Dijk. It addresses a text as a complex structure, the elements of which are interconnected both on the level of form and meaning, and the well-formedness of which should be described on both of these levels. The method addresses current problems of summary evaluation methods, especially the problem of quantifying informativity, as well as th...
Heuristic programmation for ultrasonic automatic control
International Nuclear Information System (INIS)
A study concerning the automatic characterization of flaws is presented. During a first step where simplification was looked for, the use of an ultrasonic transducer with two degrees of freedom allowed the development of a new method of non destructive testing. Its scope has been illustrated by several tests. Extension prospects to 3-D testing have been investigated, and heuristic procedures have been applied in order to limit testing complexity, and to maintain duration within acceptable limits
Automatic targeting of plasma spray gun
Abbatiello, Leonard A.; Neal, Richard E.
1978-01-01
A means for monitoring the material portion in the flame of a plasma spray gun during spraying operations is provided. A collimated detector, sensitive to certain wavelengths of light emission, is used to locate the centroid of the material with each pass of the gun. The response from the detector is then relayed to the gun controller to be used to automatically realign the gun.
Toward automatic GIS-video initial registration
Sourimant, Gaël; Colleu, Thomas; Jantet, Vincent; Morin, Luce; Bouatouch, Kadi
2012-01-01
In the context of registration between videos and geographic information system (GIS)-based 3D building models--for instance in augmented reality applications--we propose a solution to one of the most critical problems, namely the registration initialization. Successful automatic 2D/3D matching is achieved by combining two context-dependent improvements. On one hand, we associate semantic information to the low-level primitives we used to reduce the problem complexity. On the other hand, we a...
Automatic Reformulation of Children's Search Queries
Kalsbeek, van, A.; De, Wit, A.; Trieschnigg, Dolf; Vet, de, H.C.W.; Huibers, Theo; Hiemstra, Djoerd
2010-01-01
The number of children that have access to an Internet connection (at home or at school) is large and growing fast. Many of these children search the web by using a search engine. These search engines do not consider their skills and preferences however, which makes searching difficult. This paper tries to uncover methods and techniques that can be used to automatically improve search results on queries formulated by children. In order to achieve this, a prototype of a query expander is built...
Automatic Multilevel Medical Image Annotation and Retrieval
Mueen, A.; Zainuddin, R.; Baba, M. Sapiyan
2007-01-01
Image retrieval at the semantic level mostly depends on image annotation or image classification. Image annotation performance largely depends on three issues: (1) automatic image feature extraction; (2) a semantic image concept modeling; (3) algorithm for semantic image annotation. To address first issue, multilevel features are extracted to construct the feature vector, which represents the contents of the image. To address second issue, domain-dependent concept hierarchy is constructed for...
Automatic Gait Recognition by Symmetry Analysis
Hayfron-Acquah, James B.; Nixon, Mark S.; Carter, John N.
2001-01-01
We describe a new method for automatic gait recognition based on analysing the symmetry of human motion, by using the Generalised Symmetry Operator. This operator, rather than relying on the borders of a shape or on general appearance, locates features by their symmetrical properties. This approach is reinforced by the psychologists' view that gait is a symmetrical pattern of motion and by other works. We applied our new method to two different databases and derived gait signatures for silhou...
Statistical Automatic Summarization in Organic Chemistry
Boudin, Florian; Velazquez-Morales, Patricia; Torres-Moreno, Juan-Manuel
2009-01-01
We present an oriented numerical summarizer algorithm, applied to producing automatic summaries of scientific documents in Organic Chemistry. We present its implementation named Yachs (Yet Another Chemistry Summarizer) that combines a specific document pre-processing with a sentence scoring method relying on the statistical properties of documents. We show that Yachs achieves the best results among several other summarizers on a corpus of Organic Chemistry articles.
Linguistics Computation, Automatic Model Generation, and Intensions
Nourani, Cyrus F.
1994-01-01
Techniques are presented for defining models of computational linguistics theories. The methods of generalized diagrams that were developed by this author for modeling artificial intelligence planning and reasoning are shown to be applicable to models of computation of linguistics theories. It is shown that for extensional and intensional interpretations, models can be generated automatically which assign meaning to computations of linguistics theories for natural languages. Keywords: Computa...
Condition Monitoring Method for Automatic Transmission Clutches
Agusmian Partogi Ompusunggu; Jean-Michel Papy; Steve Vandenplas; Paul Sas; Hendrik Van Brussel
2012-01-01
This paper presents the development of a condition monitoring method for wet friction clutches which might be useful for automatic transmission applications. The method is developed based on quantifying the change of the relative rotational velocity signal measured between the input and output shaft of a clutch. Prior to quantifying the change, the raw velocity signal is preprocessed to capture the relative velocity signal of interest. Three dimensionless parameters, namely the normalized eng...
DiffSharp: Automatic Differentiation Library
Baydin, Atilim Gunes; Pearlmutter, Barak A; Siskind, Jeffrey Mark
2015-01-01
In this paper we introduce DiffSharp, an automatic differentiation (AD) library designed with machine learning in mind. AD is a family of techniques that evaluate derivatives at machine precision with only a small constant factor of overhead, by systematically applying the chain rule of calculus at the elementary operator level. DiffSharp aims to make an extensive array of AD techniques available, in convenient form, to the machine learning community. These including arbitrary nesting of forw...
Automatic event detection for tennis broadcasting
Enebral González, Javier
2011-01-01
Within the image digital processing framework, this thesis is situated in the automatic content indexation field. Specifically during the project, different methods and techniques will be developed in order to achieve event detection for broadcasting tennis videos. Audiovisual indexation consists in the generation of descriptive tags based on the existing audiovisual data. All these tags are used to search the desired material in an efficient way. Televisions and other entities are l...
Automatic location of short circuit faults
Energy Technology Data Exchange (ETDEWEB)
Lehtonen, M. [VTT Energy, Espoo (Finland); Hakola, T.; Antila, E. [ABB Power Oy, Helsinki (Finland); Seppaenen, M. [North-Carelian Power Company (Finland)
1996-12-31
In this presentation, the automatic location of short circuit faults on medium voltage distribution lines, based on the integration of computer systems of medium voltage distribution network automation is discussed. First the distribution data management systems and their interface with the substation telecontrol, or SCADA systems, is studied. Then the integration of substation telecontrol system and computerised relay protection is discussed. Finally, the implementation of the fault location system is presented and the practical experience with the system is discussed
Semi-Automatic Indexing of Multilingual Documents
Schiel, Ulrich; de Souza, Ianna M. Sodre Ferreira; Ferneda, Edberto
1999-01-01
With the growing significance of digital libraries and the Internet, more and more electronic texts become accessible to a wide and geographically disperse public. This requires adequate tools to facilitate indexing, storage, and retrieval of documents written in different languages. We present a method for semi-automatic indexing of electronic documents and construction of a multilingual thesaurus, which can be used for query formulation and information retrieval. We use special dictionaries...
Automatic remote correcting system for MOOCS
Rochat, Pierre-Yves
2014-01-01
An automatic correcting system was designed to be able to correct the programming exercises during a Massive Open Online Course (MOOC) about Microcontrollers, followed by thousands of students. Build around the MSP430G Launchpad, it has corrected more then 30'000 submissions in 7 weeks. This document provides general information about the system, the results obtained during a MOOC on the Coursera.org plateform, extensions done to remote experiences and future projects.
Automatic detection of abnormalities in mammograms
Suhail, Zobia; Sarwar, Mansoor; Murtaza, Kashif
2015-01-01
Background In recent years, an increased interest has been seen in the area of medical image processing and, as a consequence, Computer Aided Diagnostic (CAD) systems. The basic purpose of CAD systems is to assist doctors in the process of diagnosis. CAD systems, however, are quite expensive, especially, in most of the developing countries. Our focus is on developing a low-cost CAD system. Today, most of the CAD systems regarding mammogram classification target automatic detection of calcific...
Generating Semi-Markov Models Automatically
Johnson, Sally C.
1990-01-01
Abstract Semi-Markov Specification Interface to SURE Tool (ASSIST) program developed to generate semi-Markov model automatically from description in abstract, high-level language. ASSIST reads input file describing failure behavior of system in abstract language and generates Markov models in format needed for input to Semi-Markov Unreliability Range Evaluator (SURE) program (COSMIC program LAR-13789). Facilitates analysis of behavior of fault-tolerant computer. Written in PASCAL.
XML-Based Automatic Test Data Generation
Halil Ibrahim Bulbul; Turgut Bakir
2012-01-01
Software engineering aims at increasing quality and reliability while decreasing the cost of the software. Testing is one of the most time-consuming phases of the software development lifecycle. Improvement in software testing results in decrease in cost and increase in quality of the software. Automation in software testing is one of the most popular ways of software cost reduction and reliability improvement. In our work we propose a system called XML-based automatic test data generation th...
Monkey Gamer: Automatic profiling of Android games
Santos, Javier; Nadjm-Tehrani, Simin; Prem Bianzino, Aruna
2014-01-01
Creation of smartphone applications has undergone a massive explosion in recent years and there is an urgent need for evaluation of their resource efficiency, trustworthiness and reliability. A large proportion of these apps are going to be within the gaming area. In this paper we classify game apps on the basis of their development process, their I/O process and their interaction level. We present Monkey Gamer, a software to automatically play a large class of Android games and collect execu...
Jones, Manon W.; Snowling, Margaret J.; Moll, Kristina
2016-01-01
Reading fluency is often predicted by rapid automatized naming (RAN) speed, which as the name implies, measures the automaticity with which familiar stimuli (e.g., letters) can be retrieved and named. Readers with dyslexia are considered to have less "automatized" access to lexical information, reflected in longer RAN times compared with…
An Automatic Indirect Immunofluorescence Cell Segmentation System
Directory of Open Access Journals (Sweden)
Yung-Kuan Chan
2014-01-01
Full Text Available Indirect immunofluorescence (IIF with HEp-2 cells has been used for the detection of antinuclear autoantibodies (ANA in systemic autoimmune diseases. The ANA testing allows us to scan a broad range of autoantibody entities and to describe them by distinct fluorescence patterns. Automatic inspection for fluorescence patterns in an IIF image can assist physicians, without relevant experience, in making correct diagnosis. How to segment the cells from an IIF image is essential in developing an automatic inspection system for ANA testing. This paper focuses on the cell detection and segmentation; an efficient method is proposed for automatically detecting the cells with fluorescence pattern in an IIF image. Cell culture is a process in which cells grow under control. Cell counting technology plays an important role in measuring the cell density in a culture tank. Moreover, assessing medium suitability, determining population doubling times, and monitoring cell growth in cultures all require a means of quantifying cell population. The proposed method also can be used to count the cells from an image taken under a fluorescence microscope.
Automatic Caption Generation for Electronics Textbooks
Directory of Open Access Journals (Sweden)
Veena Thakur
2014-12-01
Full Text Available Automatic or semi-automatic approaches for developing Technology Supported Learning Systems (TSLS are required to lighten their development cost. The main objective of this paper is to automate the generation of a caption module; it aims at reproducing the way teachers prepare their lessons and the learning material they will use throughout the course. Teachers tend to choose one or more textbooks that cover the contents of their subjects, determine the topics to be addressed, and identify the parts of the textbooks which may be helpful for the students it describes the entities, attributes, role and their relationship plus the constraints that govern the problem domain. The caption model is created in order to represent the vocabulary and key concepts of the problem domain. The caption model also identifies the relationships among all the entities within the scope of the problem domain, and commonly identifies their attributes. It defines a vocabulary and is helpful as a communication tool. DOM-Sortze, a framework that enables the semi-automatic generation of the Caption Module for technology supported learning system (TSLS from electronic textbooks. The semiautomatic generation of the Caption Module entails the identification and elicitation of knowledge from the documents to which end Natural Language Processing (NLP techniques are combined with ontologies and heuristic reasoning.
AUTOMATIC CAPTION GENERATION FOR ELECTRONICS TEXTBOOKS
Directory of Open Access Journals (Sweden)
Veena Thakur
2015-10-01
Full Text Available Automatic or semi-automatic approaches for developing Technology Supported Learning Systems (TSLS are required to lighten their development cost. The main objective of this paper is to automate the generation of a caption module; it aims at reproducing the way teachers prepare their lessons and the learning material they will use throughout the course. Teachers tend to choose one or more textbooks that cover the contents of their subjects, determine the topics to be addressed, and identify the parts of the textbooks which may be helpful for the students it describes the entities, attributes, role and their relationship plus the constraints that govern the problem domain. The caption model is created in order to represent the vocabulary and key concepts of the problem domain. The caption model also identifies the relationships among all the entities within the scope of the problem domain, and commonly identifies their attributes. It defines a vocabulary and is helpful as a communication tool. DOM-Sortze, a framework that enables the semi-automatic generation of the Caption Module for technology supported learning system (TSLS from electronic textbooks. The semiautomatic generation of the Caption Module entails the identification and elicitation of knowledge from the documents to which end Natural Language Processing (NLP techniques are combined with ontologies and heuristic reasoning.
Automatic Test Pattern Generation for Digital Circuits
Directory of Open Access Journals (Sweden)
S. Hemalatha
2014-04-01
Full Text Available Digital circuits complexity and density are increasing and at the same time it should have more quality and reliability. It leads with high test costs and makes the validation more complex. The main aim is to develop a complete behavioral fault simulation and automatic test pattern generation (ATPG system for digital circuits modeled in verilog and VHDL. An integrated Automatic Test Generation (ATG and Automatic Test Executing/Equipment (ATE system for complex boards is developed here. An approach to use memristors (resistors with memory in programmable analog circuits. The Main idea consists in a circuit design in which low voltages are applied to memristors during their operation as analog circuit elements and high voltages are used to program the memristor’s states. This way, as it was demonstrated in recent experiments, the state of memristors does not essentially change during analog mode operation. As an example of our approach, we have built several programmable analog circuits demonstrating memristor -based programming of threshold, gain and frequency. In these circuits the role of memristor is played by a memristor emulator developed by us. A multiplexer is developed to generate a class of minimum transition sequences. The entire hardware is realized as digital logical circuits and the test results are simulated in Model sim software. The results of this research show that behavioral fault simulation will remain as a highly attractive alternative for the future generation of VLSI and system-on-chips (SoC.
Automatic Detection of Dominance and Expected Interest
Directory of Open Access Journals (Sweden)
M. Teresa Anguera
2010-01-01
Full Text Available Social Signal Processing is an emergent area of research that focuses on the analysis of social constructs. Dominance and interest are two of these social constructs. Dominance refers to the level of influence a person has in a conversation. Interest, when referred in terms of group interactions, can be defined as the degree of engagement that the members of a group collectively display during their interaction. In this paper, we argue that only using behavioral motion information, we are able to predict the interest of observers when looking at face-to-face interactions as well as the dominant people. First, we propose a simple set of movement-based features from body, face, and mouth activity in order to define a higher set of interaction indicators. The considered indicators are manually annotated by observers. Based on the opinions obtained, we define an automatic binary dominance detection problem and a multiclass interest quantification problem. Error-Correcting Output Codes framework is used to learn to rank the perceived observer's interest in face-to-face interactions meanwhile Adaboost is used to solve the dominant detection problem. The automatic system shows good correlation between the automatic categorization results and the manual ranking made by the observers in both dominance and interest detection problems.
Automatic Detection of Electric Power Troubles (ADEPT)
Wang, Caroline; Zeanah, Hugh; Anderson, Audie; Patrick, Clint; Brady, Mike; Ford, Donnie
1988-01-01
Automatic Detection of Electric Power Troubles (A DEPT) is an expert system that integrates knowledge from three different suppliers to offer an advanced fault-detection system. It is designed for two modes of operation: real time fault isolation and simulated modeling. Real time fault isolation of components is accomplished on a power system breadboard through the Fault Isolation Expert System (FIES II) interface with a rule system developed in-house. Faults are quickly detected and displayed and the rules and chain of reasoning optionally provided on a laser printer. This system consists of a simulated space station power module using direct-current power supplies for solar arrays on three power buses. For tests of the system's ablilty to locate faults inserted via switches, loads are configured by an INTEL microcomputer and the Symbolics artificial intelligence development system. As these loads are resistive in nature, Ohm's Law is used as the basis for rules by which faults are located. The three-bus system can correct faults automatically where there is a surplus of power available on any of the three buses. Techniques developed and used can be applied readily to other control systems requiring rapid intelligent decisions. Simulated modeling, used for theoretical studies, is implemented using a modified version of Kennedy Space Center's KATE (Knowledge-Based Automatic Test Equipment), FIES II windowing, and an ADEPT knowledge base.
Development of an automatic reactor inspection system
International Nuclear Information System (INIS)
Using recent technologies on a mobile robot computer science, we developed an automatic inspection system for weld lines of the reactor vessel. The ultrasonic inspection of the reactor pressure vessel is currently performed by commercialized robot manipulators. Since, however, the conventional fixed type robot manipulator is very huge, heavy and expensive, it needs long inspection time and is hard to handle and maintain. In order to resolve these problems, we developed a new automatic inspection system using a small mobile robot crawling on the vertical wall of the reactor vessel. According to our conceptual design, we developed the reactor inspection system including an underwater inspection robot, a laser position control subsystem, an ultrasonic data acquisition/analysis subsystem and a main control subsystem. We successfully carried out underwater experiments on the reactor vessel mockup, and real reactor ready for Ulchine nuclear power plant unit 6 at Dusan Heavy Industry in Korea. After this project, we have a plan to commercialize our inspection system. Using this system, we can expect much reduction of the inspection time, performance enhancement, automatic management of inspection history, etc. In the economic point of view, we can also expect import substitution more than 4 million dollars. The established essential technologies for intelligent control and automation are expected to be synthetically applied to the automation of similar systems in nuclear power plants
Mental imagery affects subsequent automatic defense responses
Directory of Open Access Journals (Sweden)
Muriel A Hagenaars
2015-06-01
Full Text Available Automatic defense responses promote survival and appropriate action under threat. They have also been associated with the development of threat-related psychiatric syndromes. Targeting such automatic responses during threat may be useful in populations with frequent threat exposure. Here, two experiments explored whether mental imagery as a pre-trauma manipulation could influence fear bradycardia (a core characteristic of freezing during subsequent analogue trauma (affective picture viewing. Image-based interventions have proven successful in the treatment of threat-related disorders, and are easily applicable. In Experiment 1 43 healthy participants were randomly assigned to an imagery script condition. Participants executed a passive viewing task with blocks of neutral, pleasant and unpleasant pictures after listening to an auditory script that was either related (with a positive or a negative outcome or unrelated to the unpleasant pictures from the passive viewing task. Heart rate was assessed during script listening and during passive viewing. Imagining negative related scripts resulted in greater bradycardia (neutral-unpleasant contrast than imagining positive scripts, especially unrelated. This effect was replicated in Experiment 2 (N = 51, again in the neutral-unpleasant contrast. An extra no-script condition showed that bradycardia was not induced by the negative related script, but rather that a positive script attenuated bradycardia. These preliminary results might indicate reduced vigilance after unrelated positive events. Future research should replicate these findings using a larger sample. Either way, the findings show that highly automatic defense behavior can be influenced by relatively simple mental imagery manipulations.