Periodic Orbits and Semiclassical Form Factor in Barrier Billiards

NASA Astrophysics Data System (ADS)

Giraud, O.

2005-11-01

Using heuristic arguments based on the trace formulas, we analytically calculate the semiclassical two-point correlation form factor for a family of rectangular billiards with a barrier of height irrational with respect to the side of the billiard and located at any rational position p/q from the side. To do this, we first obtain the asymptotic density of lengths for each family of periodic orbits by a Siegel-Veech formula. The result obtained for these pseudo-integrable, non-Veech billiards is different but not far from the value of 1/2 expected for semi-Poisson statistics and from values of obtained previously in the case of Veech billiards.

Indication for quantum Darwinism in electron billiards

NASA Astrophysics Data System (ADS)

Brunner, R.; Akis, R.; Meisels, R.; Kuchar, F.; Ferry, D. K.

2010-02-01

In this paper, we investigate the dynamics in electron billiards by using classical and quantum mechanical calculations. We report on the existence of pointer states in single-dot and double-dot electron billiards. Additionally, we show that the two types of pointer states have the propensity to create offspring, i.e. they can be observed in the individual modes propagating between the external reservoirs. This can be understood as an indication that quantum Darwinism is present in the electron billiards.

Ergodicity of the generalized lemon billiards

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen, Jingyu; Mohr, Luke; Zhang, Hong-Kun, E-mail: hongkun@math.umass.edu

2013-12-15

In this paper, we study a two-parameter family of convex billiard tables, by taking the intersection of two round disks (with different radii) in the plane. These tables give a generalization of the one-parameter family of lemon-shaped billiards. Initially, there is only one ergodic table among all lemon tables. In our generalized family, we observe numerically the prevalence of ergodicity among the some perturbations of that table. Moreover, numerical estimates of the mixing rate of the billiard dynamics on some ergodic tables are also provided.

Classification of billiard motions in domains bounded by confocal parabolas

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fokicheva, V V

2014-08-01

We consider the billiard dynamical system in a domain bounded by confocal parabolas. We describe such domains in which the billiard problem can be correctly stated. In each such domain we prove the integrability for the system, analyse the arising Liouville foliation, and calculate the invariant of Liouville equivalence--the so-called marked molecule. It turns out that billiard systems in certain parabolic domains have the same closures of solutions (integral trajectories) as the systems of Goryachev-Chaplygin-Sretenskii and Joukowski at suitable energy levels. We also describe the billiard motion in noncompact domains bounded by confocal parabolas, namely, we describe the topology of themore » Liouville foliation in terms of rough molecules. Bibliography: 16 titles.« less

Reversibility and stability of information processing systems

NASA Technical Reports Server (NTRS)

Zurek, W. H.

1984-01-01

Classical and quantum models of dynamically reversible computers are considered. Instabilities in the evolution of the classical 'billiard ball computer' are analyzed and shown to result in a one-bit increase of entropy per step of computation. 'Quantum spin computers', on the other hand, are not only microscopically, but also operationally reversible. Readoff of the output of quantum computation is shown not to interfere with this reversibility. Dissipation, while avoidable in principle, can be used in practice along with redundancy to prevent errors.

Scattering by a boundary with complex structure.

PubMed

Naplekov, D M; Tur, A V; Yanovsky, V V

2013-04-01

The distribution of escape times is usually studied in open billiards theory. In this work, we will concentrate on another important question: The distribution of outgoing rays by exit directions, which we refer to as billiard's indicatrix. It can be obtained analytically and consists of two parts: the symmetric diffuse part and the asymmetric directed part. The criterion for the separation of the indicatrix into these two parts is established. The asymmetry of the directed part of the indicatrix and the influence of the billiard's borders on it is investigated. We also propose a method of the creation of a matte surface model using open billiards with a fully diffuse indicatrix.

The behaviour of resonances in Hecke triangular billiards under deformation

NASA Astrophysics Data System (ADS)

Howard, P. J.; O'Mahony, P. F.

2007-08-01

The right-hand boundary of Artin's billiard on the Poincaré half-plane is continuously deformed to generate a class of chaotic billiards which includes fundamental domains of the Hecke groups Γ(2, n) at certain values of the deformation parameter. The quantum scattering problem in these open chaotic billiards is described and the distributions of both real and imaginary parts of the resonant eigenvalues are investigated. The transitions to arithmetic chaos in the cases n ∈ {4, 6} are closely examined and the explicit analytic form for the scattering matrix is given together with the Fourier coefficients for the scattered wavefunction. The n = 4 and 6 cases have an additional set of regular equally spaced resonances compared to Artin's billiard (n = 3). For a general deformation, a numerical procedure is presented which generates the resonance eigenvalues and the evolution of the eigenvalues is followed as the boundary is varied continuously which leads to dramatic changes in their distribution. For deformations away from the non-generic arithmetic cases, including that of the tiling Hecke triangular billiard n = 5, the distributions of the positions and widths of the resonances are consistent with the predictions of a random matrix theory.

Gutkin billiard tables in higher dimensions and rigidity

NASA Astrophysics Data System (ADS)

Bialy, Misha

2018-05-01

Gutkin found a remarkable class of convex billiard tables in a plane that has a constant angle invariant curve. In this paper we prove that in dimension 3 only a round sphere has such a property. For dimensions greater than 3, a hypersurface with a Gutkin property different from a round sphere, if it exists, must be of constant width and, moreover, it must have very special geometric properties. In the 2D case we prove a rigidity result for Gutkin billiard tables. This is done with the help of a new generating function introduced recently for billiards in our joint paper with Mironov. In the present paper a formula for the generating function in higher dimensions is found.

Exploiting broad-area surface emitting lasers to manifest the path-length distributions of finite-potential quantum billiards.

PubMed

Yu, Y T; Tuan, P H; Chang, K C; Hsieh, Y H; Huang, K F; Chen, Y F

2016-01-11

Broad-area vertical-cavity surface-emitting lasers (VCSELs) with different cavity sizes are experimentally exploited to manifest the influence of the finite confinement strength on the path-length distribution of quantum billiards. The subthreshold emission spectra of VCSELs are measured to obtain the path-length distributions by using the Fourier transform. It is verified that the number of the resonant peaks in the path-length distribution decreases with decreasing the confinement strength. Theoretical analyses for finite-potential quantum billiards are numerically performed to confirm that the mesoscopic phenomena of quantum billiards with finite confinement strength can be analogously revealed by using broad-area VCSELs.

Statistics of resonances for a class of billiards on the Poincaré half-plane

NASA Astrophysics Data System (ADS)

Howard, P. J.; Mota-Furtado, F.; O'Mahony, P. F.; Uski, V.

2005-12-01

The lower boundary of Artin's billiard on the Poincaré half-plane is continuously deformed to generate a class of billiards with classical dynamics varying from fully integrable to completely chaotic. The quantum scattering problem in these open billiards is described and the statistics of both real and imaginary parts of the resonant momenta are investigated. The evolution of the resonance positions is followed as the boundary is varied which leads to large changes in their distribution. The transition to arithmetic chaos in Artin's billiard, which is responsible for the Poissonian level-spacing statistics of the bound states in the continuum (cusp forms) at the same time as the formation of a set of resonances all with width \\frac{1}{4} and real parts determined by the zeros of Riemann's zeta function, is closely examined. Regimes are found which obey the universal predictions of random matrix theory (RMT) as well as exhibiting non-universal long-range correlations. The Brody parameter is used to describe the transitions between different regimes.

Analysis of resonant population transfer in time-dependent elliptical quantum billiards

NASA Astrophysics Data System (ADS)

Liss, Jakob; Liebchen, Benno; Schmelcher, Peter

2013-01-01

A Fermi golden rule for population transfer between instantaneous eigenstates of elliptical quantum billiards with oscillating boundaries is derived. Thereby the occurrence of both the recently observed resonant population transfer between instantaneous eigenstates and the empirical criterion stating that these transitions occur when the driving frequency matches the mean difference of the latter [Lenz , New J. Phys.NJOPFM1367-263010.1088/1367-2630/13/10/103019 13, 103019 (2011)] is explained. As a second main result a criterion judging which resonances are resolvable in a corresponding experiment of certain duration is provided. Our analysis is complemented by numerical simulations for three different driving laws. The corresponding resonance spectra are in agreement with the predictions of both criteria.

BILLIARDS: Baseline Instrumented Lithology Lander, Inspector and Asteroid Redirection Demonstration System

NASA Technical Reports Server (NTRS)

Marcus, Matthew; Sloane, Joshua; Ortiz, Oliver; Barbee, Brent

2015-01-01

BILLIARDS Baseline Instrumented Lithology Lander, Inspector, and Asteroid Redirection Demonstration System Proposed demonstration mission for Billiard-Ball concept Select asteroid pair with natural close approach to minimize cost and complexity Primary Objectives Rendezvous with a small (10m), near Earth (alpha) asteroid Maneuver the alpha asteroid to a collision with a 100m (beta) asteroid Produce a detectable deflection or disruption of the beta asteroid Secondary objectives Contribute knowledge of asteroid composition and characteristics Contribute knowledge of small-body formation Opportunity for international collaboration

Shannon entropy and avoided crossings in closed and open quantum billiards

NASA Astrophysics Data System (ADS)

Park, Kyu-Won; Moon, Songky; Shin, Younghoon; Kim, Jinuk; Jeong, Kabgyun; An, Kyungwon

2018-06-01

The relation between Shannon entropy and avoided crossings is investigated in dielectric microcavities. The Shannon entropy of the probability density for eigenfunctions in an open elliptic billiard as well as a closed quadrupole billiard increases as the center of the avoided crossing is approached. These results are opposite to those of atomic physics for electrons. It is found that the collective Lamb shift of the open quantum system and the symmetry breaking in the closed chaotic quantum system have equivalent effects on the Shannon entropy.

Signatures of chaos in the Brillouin zone.

PubMed

Barr, Aaron; Barr, Ariel; Porter, Max D; Reichl, Linda E

2017-10-01

When the classical dynamics of a particle in a finite two-dimensional billiard undergoes a transition to chaos, the quantum dynamics of the particle also shows manifestations of chaos in the form of scarring of wave functions and changes in energy level spacing distributions. If we "tile" an infinite plane with such billiards, we find that the Bloch states on the lattice undergo avoided crossings, energy level spacing statistics change from Poisson-like to Wigner-like, and energy sheets of the Brillouin zone begin to "mix" as the classical dynamics of the billiard changes from regular to chaotic behavior.

A nodal domain theorem for integrable billiards in two dimensions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Samajdar, Rhine; Jain, Sudhir R., E-mail: srjain@barc.gov.in

Eigenfunctions of integrable planar billiards are studied — in particular, the number of nodal domains, ν of the eigenfunctions with Dirichlet boundary conditions are considered. The billiards for which the time-independent Schrödinger equation (Helmholtz equation) is separable admit trivial expressions for the number of domains. Here, we discover that for all separable and non-separable integrable billiards, ν satisfies certain difference equations. This has been possible because the eigenfunctions can be classified in families labelled by the same value of mmodkn, given a particular k, for a set of quantum numbers, m,n. Further, we observe that the patterns in a familymore » are similar and the algebraic representation of the geometrical nodal patterns is found. Instances of this representation are explained in detail to understand the beauty of the patterns. This paper therefore presents a mathematical connection between integrable systems and difference equations. - Highlights: • We find that the number of nodal domains of eigenfunctions of integrable, planar billiards satisfy a class of difference equations. • The eigenfunctions labelled by quantum numbers (m,n) can be classified in terms of mmodkn. • A theorem is presented, realising algebraic representations of geometrical patterns exhibited by the domains. • This work presents a connection between integrable systems and difference equations.« less

Billiards in the Classroom: Learning Physics with Microworlds.

ERIC Educational Resources Information Center

Bertz, Michael D.

1997-01-01

Trickshot! is an exploratory environment that allows learners to experiment with various physical properties to develop an intuitive understanding of the behavior of objects in physical systems. The software is geared to secondary students with little exposure to pool or physics. When used in conjunction with meaningful class activities, such an…

Bouncing droplets on a billiard table.

PubMed

Shirokoff, David

2013-03-01

In a set of experiments, Couder et al. demonstrate that an oscillating fluid bed may propagate a bouncing droplet through the guidance of the surface waves. I present a dynamical systems model, in the form of an iterative map, for a droplet on an oscillating bath. I examine the droplet bifurcation from bouncing to walking, and prescribe general requirements for the surface wave to support stable walking states. I show that in addition to walking, there is a region of large forcing that may support the chaotic motion of the droplet. Using the map, I then investigate the droplet trajectories in a square (billiard ball) domain. I show that in large domains, the long time trajectories are either non-periodic dense curves or approach a quasiperiodic orbit. In contrast, in small domains, at low forcing, trajectories tend to approach an array of circular attracting sets. As the forcing increases, the attracting sets break down and the droplet travels throughout space.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Manjunath, Naren; Samajdar, Rhine; Jain, Sudhir R., E-mail: srjain@barc.gov.in

Recently, the nodal domain counts of planar, integrable billiards with Dirichlet boundary conditions were shown to satisfy certain difference equations in Samajdar and Jain (2014). The exact solutions of these equations give the number of domains explicitly. For complete generality, we demonstrate this novel formulation for three additional separable systems and thus extend the statement to all integrable billiards.

Linear and nonlinear stability of periodic orbits in annular billiards.

PubMed

Dettmann, Carl P; Fain, Vitaly

2017-04-01

An annular billiard is a dynamical system in which a particle moves freely in a disk except for elastic collisions with the boundary and also a circular scatterer in the interior of the disk. We investigate the stability properties of some periodic orbits in annular billiards in which the scatterer is touching or close to the boundary. We analytically show that there exist linearly stable periodic orbits of an arbitrary period for scatterers with decreasing radii that are located near the boundary of the disk. As the position of the scatterer moves away from a symmetry line of a periodic orbit, the stability of periodic orbits changes from elliptic to hyperbolic, corresponding to a saddle-center bifurcation. When the scatterer is tangent to the boundary, the periodic orbit is parabolic. We prove that slightly changing the reflection angle of the orbit in the tangential situation leads to the existence of Kolmogorov-Arnold-Moser islands. Thus, we show that there exists a decreasing to zero sequence of open intervals of scatterer radii, along which the billiard table is not ergodic.

Linear and nonlinear stability of periodic orbits in annular billiards

NASA Astrophysics Data System (ADS)

Dettmann, Carl P.; Fain, Vitaly

2017-04-01

An annular billiard is a dynamical system in which a particle moves freely in a disk except for elastic collisions with the boundary and also a circular scatterer in the interior of the disk. We investigate the stability properties of some periodic orbits in annular billiards in which the scatterer is touching or close to the boundary. We analytically show that there exist linearly stable periodic orbits of an arbitrary period for scatterers with decreasing radii that are located near the boundary of the disk. As the position of the scatterer moves away from a symmetry line of a periodic orbit, the stability of periodic orbits changes from elliptic to hyperbolic, corresponding to a saddle-center bifurcation. When the scatterer is tangent to the boundary, the periodic orbit is parabolic. We prove that slightly changing the reflection angle of the orbit in the tangential situation leads to the existence of Kolmogorov-Arnold-Moser islands. Thus, we show that there exists a decreasing to zero sequence of open intervals of scatterer radii, along which the billiard table is not ergodic.

Constrained Quantum Mechanics: Chaos in Non-Planar Billiards

ERIC Educational Resources Information Center

Salazar, R.; Tellez, G.

2012-01-01

We illustrate some of the techniques to identify chaos signatures at the quantum level using as guiding examples some systems where a particle is constrained to move on a radial symmetric, but non-planar, surface. In particular, two systems are studied: the case of a cone with an arbitrary contour or "dunce hat billiard" and the rectangular…

Realization of discrete quantum billiards in a two-dimensional optical lattice

DOE Office of Scientific and Technical Information (OSTI.GOV)

Krimer, Dmitry O.; Max-Planck Institute for the Physics of Complex Systems, Noethnitzer Strasse 38, D-01187 Dresden; Khomeriki, Ramaz

2011-10-15

We propose a method for optical visualization of the Bose-Hubbard model with two interacting bosons in the form of two-dimensional (2D) optical lattices consisting of optical waveguides, where the waveguides at the diagonal are characterized by different refractive indices than others elsewhere, modeling the boson-boson interaction. We study the light intensity distribution function averaged over the direction of propagation for both ordered and disordered cases, exploring the sensitivity of the averaged picture with respect to the beam injection position. For our finite systems, the resulting patterns are reminiscent the ones set in billiards, and therefore we introduce a definition ofmore » discrete quantum billiards and discuss the possible relevance to its well-established continuous counterpart.« less

Nontrivial paths and periodic orbits of the T-fractal billiard table

NASA Astrophysics Data System (ADS)

Lapidus, Michel L.; Miller, Robyn L.; Niemeyer, Robert G.

2016-07-01

We introduce and prove numerous new results about the orbits of the T-fractal billiard. Specifically, in section 3, we give a variety of sufficient conditions for the existence of a sequence of compatible periodic orbits. In section 4, we examine the limiting behavior of particular sequences of compatible periodic orbits. Additionally, sufficient conditions for the existence of particular nontrivial paths are given in section 4. The proofs of two results of Lapidus and Niemeyer (2013 The current state of fractal billiards Fractal Geometry and Dynamical Systems in Pure and Applied Mathematics II: Fractals in Applied Mathematics (Contemporary Mathematics vol 601) ed D Carfi et al (Providence, RI: American Mathematical Society) pp 251-88 (e-print: arXiv:math.DS.1210.0282v2, 2013) appear here for the first time, as well. In section 5, an orbit with an irrational initial direction reaches an elusive point in a way that yields a nontrivial path of finite length, yet, by our convention, constitutes a singular orbit of the fractal billiard table. The existence of such an orbit seems to indicate that the classification of orbits may not be so straightforward. A discussion of our results and directions for future research is then given in section 6.

Transport in the barrier billiard

NASA Astrophysics Data System (ADS)

Saberi Fathi, S. M.; Ettoumi, W.; Courbage, M.

2016-06-01

We investigate transport properties of an ensemble of particles moving inside an infinite periodic horizontal planar barrier billiard. A particle moves among bars and elastically reflects on them. The motion is a uniform translation along the bars' axis. When the tangent of the incidence angle, α , is fixed and rational, the second moment of the displacement along the orthogonal axis at time n , , is either bounded or asymptotic to K n2 , when n →∞ . For irrational α , the collision map is ergodic and has a family of weakly mixing observables, the transport is not ballistic, and autocorrelation functions decay only in time average, but may not decay for a family of irrational α 's. An exhaustive numerical computation shows that the transport may be superdiffusive or subdiffusive with various rates or bounded strongly depending on the values of α . The variety of transport behaviors sounds reminiscent of well-known behavior of conservative systems. Considering then an ensemble of particles with nonfixed α , the system is nonergodic and certainly not mixing and has anomalous diffusion with self-similar space-time properties. However, we verified that such a system decomposes into ergodic subdynamics breaking self-similarity.

Arnold tongues in a billiard problem in nonlinear and nonequilibrium systems

NASA Astrophysics Data System (ADS)

Miyaji, Tomoyuki

2017-02-01

We study a billiard problem in nonlinear and nonequilibrium systems. This is motivated by the motions of a traveling spot in a reaction-diffusion system (RDS) in a rectangular domain. We consider a four-dimensional dynamical system, defined by ordinary differential equations. This was first derived by S.-I. Ei et al. (2006), based on a reduced system on the center manifold in a neighborhood of a pitchfork bifurcation of a stationary spot for the RDS. In contrast to the classical billiard problem, this defines a dynamical system that is dissipative rather than conservative, and has an attractor. According to previous numerical studies, the attractor of the system changes depending on parameters such as the aspect ratio of the domain. It may be periodic, quasi-periodic, or chaotic. In this paper, we elucidate that it results from parameters crossing Arnold tongues and that the organizing center is a Hopf-Hopf bifurcation of the trivial equilibrium.

Short-Term Impact of a Comprehensive Smoke-Free Law Following a Partial Smoke-Free Law on PM2.5 Concentration Levels at Hospitality Venues on the Peripheries of College Campuses

PubMed Central

Yu, Sol; Yang, Wonho; Lee, Kiyoung; Kim, Sungcheon; Ha, Kwonchul; Kim, Sungroul

2015-01-01

Tobacco-free policies on college campuses are spreading in Korea. However, the impact of the smoking ban legislation at venues on the boundary of a college campus is still limited. This study aimed to assess short-term changes in PM2.5 concentrations before and after the enactment of the smoking ban legislation to evaluate the impact. In this cross-sectional study, PM2.5 measurements (pre-ban: n = 99, post-ban: n = 64) were conducted in randomly selected billiards, pubs, and computer game rooms on the peripheries of college campuses in October 2013, prior to implementation of the smoking ban, and in May 2014, after the ban. The median (interquartile range, IQR) of the PM2.5 concentration for all venues was 31 μg/m3 (0–80 μg/m3) in the pre-ban period and 11 μg/m3 (0–36 μg/m3) in the post-ban period implying indoor PM2.5 concentration levels of the peripheries of college campuses likely decreased one year after implementation of the ban. However, the differences were not significant yet. The results support the introduction of more rigorous monitoring of SHS exposure levels toward the ultimate goal of encouraging a complete smoking ban in hospitality venues, including billiards, pubs, and computer game rooms located on the peripheries of college campuses. PMID:26540063

Short-Term Impact of a Comprehensive Smoke-Free Law Following a Partial Smoke-Free Law on PM₂.₅ Concentration Levels at Hospitality Venues on the Peripheries of College Campuses.

PubMed

Yu, Sol; Yang, Wonho; Lee, Kiyoung; Kim, Sungcheon; Ha, Kwonchul; Kim, Sungroul

2015-11-02

Tobacco-free policies on college campuses are spreading in Korea. However, the impact of the smoking ban legislation at venues on the boundary of a college campus is still limited. This study aimed to assess short-term changes in PM2.5 concentrations before and after the enactment of the smoking ban legislation to evaluate the impact. In this cross-sectional study, PM2.5 measurements (pre-ban: n = 99, post-ban: n = 64) were conducted in randomly selected billiards, pubs, and computer game rooms on the peripheries of college campuses in October 2013, prior to implementation of the smoking ban, and in May 2014, after the ban. The median (interquartile range, IQR) of the PM2.5 concentration for all venues was 31 μg/m³ (0-80 μg/m³) in the pre-ban period and 11 μg/m³ (0-36 μg/m³) in the post-ban period implying indoor PM2.5 concentration levels of the peripheries of college campuses likely decreased one year after implementation of the ban. However, the differences were not significant yet. The results support the introduction of more rigorous monitoring of SHS exposure levels toward the ultimate goal of encouraging a complete smoking ban in hospitality venues, including billiards, pubs, and computer game rooms located on the peripheries of college campuses.

Doorway states and billiards

NASA Astrophysics Data System (ADS)

Franco-Villafañe, J. A.; Flores, J.; Mateos, J. L.; Méndez-Sánchez, R. A.; Novaro, O.; Seligman, T. H.

2010-12-01

Whenever a distinct state is immersed in a sea of complicated and dense states, the strength of the distinct state, which we refer to as a doorway, is distributed in their neighboring states. We analyze this mechanism for 2-D billiards with different geometries. One of them is symmetric and integrable, another is symmetric but chaotic, and the third has a capricious form. The fact that the doorway-state mechanism is valid for such highly diverse cases, proves that it is robust.

Doorway states and billiards

DOE Office of Scientific and Technical Information (OSTI.GOV)

Franco-Villafane, J. A.; Mendez-Sanchez, R. A.; Flores, J.

2010-12-23

Whenever a distinct state is immersed in a sea of complicated and dense states, the strength of the distinct state, which we refer to as a doorway, is distributed in their neighboring states. We analyze this mechanism for 2-D billiards with different geometries. One of them is symmetric and integrable, another is symmetric but chaotic, and the third has a capricious form. The fact that the doorway-state mechanism is valid for such highly diverse cases, proves that it is robust.

Newton’s cradle in billiards and croquet

NASA Astrophysics Data System (ADS)

Cross, Rod

2016-11-01

When an object collides head-on and in line with two balls in contact, the outcome is not generally easy to predict. We consider three simple examples. One is Newton’s cradle with only three balls. Another is a billiard cue colliding with the two balls. The third is a croquet shot where a mallet collides with the two balls. The outcome in each case is different since it depends on the mass of the colliding object.

Heat conduction in a chain of colliding particles with a stiff repulsive potential

NASA Astrophysics Data System (ADS)

Gendelman, Oleg V.; Savin, Alexander V.

2016-11-01

One-dimensional billiards, i.e., a chain of colliding particles with equal masses, is a well-known example of a completely integrable system. Billiards with different particle masses is generically not integrable, but it still exhibits divergence of a heat conduction coefficient (HCC) in the thermodynamic limit. Traditional billiards models imply instantaneous (zero-time) collisions between the particles. We relax this condition of instantaneous impact and consider heat transport in a chain of stiff colliding particles with the power-law potential of the nearest-neighbor interaction. The instantaneous collisions correspond to the limit of infinite power in the interaction potential; for finite powers, the interactions take nonzero time. This modification of the model leads to a profound physical consequence—the probability of multiple (in particular triple) -particle collisions becomes nonzero. Contrary to the integrable billiards of equal particles, the modified model exhibits saturation of the heat conduction coefficient for a large system size. Moreover, the identification of scattering events with triple-particle collisions leads to a simple definition of the characteristic mean free path and a kinetic description of heat transport. This approach allows us to predict both the temperature and density dependencies for the HCC limit values. The latter dependence is quite counterintuitive—the HCC is inversely proportional to the particle density in the chain. Both predictions are confirmed by direct numerical simulations.

Visualising Berry phase and diabolical points in a quantum exciton-polariton billiard

PubMed Central

Estrecho, E.; Gao, T.; Brodbeck, S.; Kamp, M.; Schneider, C.; Höfling, S.; Truscott, A. G.; Ostrovskaya, E. A.

2016-01-01

Diabolical points (spectral degeneracies) can naturally occur in spectra of two-dimensional quantum systems and classical wave resonators due to simple symmetries. Geometric Berry phase is associated with these spectral degeneracies. Here, we demonstrate a diabolical point and the corresponding Berry phase in the spectrum of hybrid light-matter quasiparticles—exciton-polaritons in semiconductor microcavities. It is well known that sufficiently strong optical pumping can drive exciton-polaritons to quantum degeneracy, whereby they form a macroscopically populated quantum coherent state similar to a Bose-Einstein condensate. By pumping a microcavity with a spatially structured light beam, we create a two-dimensional quantum billiard for the exciton-polariton condensate and demonstrate a diabolical point in the spectrum of the billiard eigenstates. The fully reconfigurable geometry of the potential walls controlled by the optical pump enables a striking experimental visualization of the Berry phase associated with the diabolical point. The Berry phase is observed and measured by direct imaging of the macroscopic exciton-polariton probability densities. PMID:27886222

Robotic Billiards: Understanding Humans in Order to Counter Them.

PubMed

Nierhoff, Thomas; Leibrandt, Konrad; Lorenz, Tamara; Hirche, Sandra

2016-08-01

Ongoing technological advances in the areas of computation, sensing, and mechatronics enable robotic-based systems to interact with humans in the real world. To succeed against a human in a competitive scenario, a robot must anticipate the human behavior and include it in its own planning framework. Then it can predict the next human move and counter it accordingly, thus not only achieving overall better performance but also systematically exploiting the opponent's weak spots. Pool is used as a representative scenario to derive a model-based planning and control framework where not only the physics of the environment but also a model of the opponent is considered. By representing the game of pool as a Markov decision process and incorporating a model of the human decision-making based on studies, an optimized policy is derived. This enables the robot to include the opponent's typical game style into its tactical considerations when planning a stroke. The results are validated in simulations and real-life experiments with an anthropomorphic robot playing pool against a human.

Observation of non-Hermitian degeneracies in a chaotic exciton-polariton billiard.

PubMed

Gao, T; Estrecho, E; Bliokh, K Y; Liew, T C H; Fraser, M D; Brodbeck, S; Kamp, M; Schneider, C; Höfling, S; Yamamoto, Y; Nori, F; Kivshar, Y S; Truscott, A G; Dall, R G; Ostrovskaya, E A

2015-10-22

Exciton-polaritons are hybrid light-matter quasiparticles formed by strongly interacting photons and excitons (electron-hole pairs) in semiconductor microcavities. They have emerged as a robust solid-state platform for next-generation optoelectronic applications as well as for fundamental studies of quantum many-body physics. Importantly, exciton-polaritons are a profoundly open (that is, non-Hermitian) quantum system, which requires constant pumping of energy and continuously decays, releasing coherent radiation. Thus, the exciton-polaritons always exist in a balanced potential landscape of gain and loss. However, the inherent non-Hermitian nature of this potential has so far been largely ignored in exciton-polariton physics. Here we demonstrate that non-Hermiticity dramatically modifies the structure of modes and spectral degeneracies in exciton-polariton systems, and, therefore, will affect their quantum transport, localization and dynamical properties. Using a spatially structured optical pump, we create a chaotic exciton-polariton billiard--a two-dimensional area enclosed by a curved potential barrier. Eigenmodes of this billiard exhibit multiple non-Hermitian spectral degeneracies, known as exceptional points. Such points can cause remarkable wave phenomena, such as unidirectional transport, anomalous lasing/absorption and chiral modes. By varying parameters of the billiard, we observe crossing and anti-crossing of energy levels and reveal the non-trivial topological modal structure exclusive to non-Hermitian systems. We also observe mode switching and a topological Berry phase for a parameter loop encircling the exceptional point. Our findings pave the way to studies of non-Hermitian quantum dynamics of exciton-polaritons, which may uncover novel operating principles for polariton-based devices.

On the Computing Potential of Intracellular Vesicles

PubMed Central

Mayne, Richard; Adamatzky, Andrew

2015-01-01

Collision-based computing (CBC) is a form of unconventional computing in which travelling localisations represent data and conditional routing of signals determines the output state; collisions between localisations represent logical operations. We investigated patterns of Ca2+-containing vesicle distribution within a live organism, slime mould Physarum polycephalum, with confocal microscopy and observed them colliding regularly. Vesicles travel down cytoskeletal ‘circuitry’ and their collisions may result in reflection, fusion or annihilation. We demonstrate through experimental observations that naturally-occurring vesicle dynamics may be characterised as a computationally-universal set of Boolean logical operations and present a ‘vesicle modification’ of the archetypal CBC ‘billiard ball model’ of computation. We proceed to discuss the viability of intracellular vesicles as an unconventional computing substrate in which we delineate practical considerations for reliable vesicle ‘programming’ in both in vivo and in vitro vesicle computing architectures and present optimised designs for both single logical gates and combinatorial logic circuits based on cytoskeletal network conformations. The results presented here demonstrate the first characterisation of intracelluar phenomena as collision-based computing and hence the viability of biological substrates for computing. PMID:26431435

Coupling-Induced Bipartite Pointer States in Arrays of Electron Billiards: Quantum Darwinism in Action?

NASA Astrophysics Data System (ADS)

Brunner, R.; Akis, R.; Ferry, D. K.; Kuchar, F.; Meisels, R.

2008-07-01

We discuss a quantum system coupled to the environment, composed of an open array of billiards (dots) in series. Beside pointer states occurring in individual dots, we observe sets of robust states which arise only in the array. We define these new states as bipartite pointer states, since they cannot be described in terms of simple linear combinations of robust single-dot states. The classical existence of bipartite pointer states is confirmed by comparing the quantum-mechanical and classical results. The ability of the robust states to create “offspring” indicates that quantum Darwinism is in action.

Coupling-induced bipartite pointer states in arrays of electron billiards: quantum Darwinism in action?

PubMed

Brunner, R; Akis, R; Ferry, D K; Kuchar, F; Meisels, R

2008-07-11

We discuss a quantum system coupled to the environment, composed of an open array of billiards (dots) in series. Beside pointer states occurring in individual dots, we observe sets of robust states which arise only in the array. We define these new states as bipartite pointer states, since they cannot be described in terms of simple linear combinations of robust single-dot states. The classical existence of bipartite pointer states is confirmed by comparing the quantum-mechanical and classical results. The ability of the robust states to create "offspring" indicates that quantum Darwinism is in action.

Some new surprises in chaos.

PubMed

Bunimovich, Leonid A; Vela-Arevalo, Luz V

2015-09-01

"Chaos is found in greatest abundance wherever order is being sought.It always defeats order, because it is better organized"Terry PratchettA brief review is presented of some recent findings in the theory of chaotic dynamics. We also prove a statement that could be naturally considered as a dual one to the Poincaré theorem on recurrences. Numerical results demonstrate that some parts of the phase space of chaotic systems are more likely to be visited earlier than other parts. A new class of chaotic focusing billiards is discussed that clearly violates the main condition considered to be necessary for chaos in focusing billiards.

Limit Theorems for Dispersing Billiards with Cusps

NASA Astrophysics Data System (ADS)

Bálint, P.; Chernov, N.; Dolgopyat, D.

2011-12-01

Dispersing billiards with cusps are deterministic dynamical systems with a mild degree of chaos, exhibiting "intermittent" behavior that alternates between regular and chaotic patterns. Their statistical properties are therefore weak and delicate. They are characterized by a slow (power-law) decay of correlations, and as a result the classical central limit theorem fails. We prove that a non-classical central limit theorem holds, with a scaling factor of {sqrt{nlog n}} replacing the standard {sqrt{n}} . We also derive the respective Weak Invariance Principle, and we identify the class of observables for which the classical CLT still holds.

Modeling and Simulation of the Dynamics of Dissipative, Inelastic Spheres with Applications to Planetary Rovers and Gravitational Billiards

NASA Astrophysics Data System (ADS)

Hartl, Alexandre E.

This dissertation provides a thorough treatment on the dynamic modeling and simulation of spherical objects, and its applications to planetary rovers and gravitational billiards. First, the equations governing the motion of a wind-driven spherical rover are developed, and a numerical procedure for their implementation is shown. Dynamic simulations (considering the Earth and Mars atmospheres) for several terrain types and conditions illustrate how a rover may maneuver across flat terrain, channels and craters. The effects of aerodynamic forces on the rover's motion is studied. The results show the wind force may both push and hinder the rover's motion while sliding, rolling and bouncing. The rover will periodically transition between these modes of movement when the rover impacts sloped surfaces. Combinations of rolling and bouncing may be a more effective means of transport for a rover traveling through a channel when compared to rolling alone. The aerodynamic effects, of drag and the Magnus force, are contributing factors to the possible capture of the rover by a crater. Next, a strategy is formulated for creating randomized Martian rock fields based on statistical models, where the rover's interactions with these fields are analyzed. Novel procedures for creating randomized Martian rock fields are presented, where optimization techniques allow terrain generation to coincide with the rover's motion. Efficient collision detection routines reduce the number of tests of potential collisions between the rover and the terrain while establishing new contact constraints. The procedures allow for the exploration of large regions of terrain while minimizing computational costs. Simulations demonstrate that bouncing is the rover's dominant mode of travel through the rock fields. Monte-Carlo simulations illustrate how the rover's down-range position depends on the rover design and atmospheric conditions. Moreover, the simulations verify the rover's capacity for long distance travel over Martian rock fields. Finally, a mathematical model that captures the essential dynamics required for describing the motion of a real world billiard for arbitrary boundaries is presented. The model considers the more realistic situation of an inelastic, rotating, gravitational billiard in which there are retarding forces due to air resistance and friction. The simulations demonstrate that the parabola has stable, periodic motion, while the wedge and hyperbola, at high driving frequencies, appear chaotic. The hyperbola, at low driving frequencies, behaves similarly to the parabola, and has regular motion. Direct comparisons are made between the model's predictions and previously published experimental data. The representation of the coefficient of restitution employed in the model resulted in good agreement with the experimental data for all boundary shapes investigated. It is shown that the data can be successfully modeled with a simple set of parameters without an assumption of exotic energy dependence.

G. E. M. Jauncey and the Compton Effect

NASA Astrophysics Data System (ADS)

Jenkin, John

In late 1922 Arthur Holly Compton (1892-1962) discovered that an X-ray quantum of radiation undergoes a discrete change in wavelength when it experiences a billiard-ball collision with a single atomic electron, a phenomenon that became known as the Compton effect and for which he shared the Nobel Prize in Physics for 1927. But for more than five years before he made his discovery, Compton had analyzed X-ray scattering in terms of classical electrodynamics. I suggest that his colleague at Washington University in St. Louis, G. E. M. Jauncey (1888-1947), helped materially to persuade him to embrace the quantum interpretation of his X-ray scattering experiments.

First experimental test of a trace formula for billiard systems showing mixed dynamics.

PubMed

Dembowski, C; Gräf, H D; Heine, A; Hesse, T; Rehfeld, H; Richter, A

2001-04-09

In general, trace formulas relate the density of states for a given quantum mechanical system to the properties of the periodic orbits of its classical counterpart. Here we report for the first time on a semiclassical description of microwave spectra taken from superconducting billiards of the Limaçon family showing mixed dynamics in terms of a generalized trace formula derived by Ullmo et al. [Phys. Rev. E 54, 136 (1996)]. This expression not only describes mixed-typed behavior but also the limiting cases of fully regular and fully chaotic systems and thus presents a continuous interpolation between the Berry-Tabor and Gutzwiller formulas.

Equilibration of energy in slow–fast systems

PubMed Central

Shah, Kushal; Gelfreich, Vassili; Rom-Kedar, Vered

2017-01-01

Ergodicity is a fundamental requirement for a dynamical system to reach a state of statistical equilibrium. However, in systems with several characteristic timescales, the ergodicity of the fast subsystem impedes the equilibration of the whole system because of the presence of an adiabatic invariant. In this paper, we show that violation of ergodicity in the fast dynamics can drive the whole system to equilibrium. To show this principle, we investigate the dynamics of springy billiards, which are mechanical systems composed of a small particle bouncing elastically in a bounded domain, where one of the boundary walls has finite mass and is attached to a linear spring. Numerical simulations show that the springy billiard systems approach equilibrium at an exponential rate. However, in the limit of vanishing particle-to-wall mass ratio, the equilibration rates remain strictly positive only when the fast particle dynamics reveal two or more ergodic components for a range of wall positions. For this case, we show that the slow dynamics of the moving wall can be modeled by a random process. Numerical simulations of the corresponding springy billiards and their random models show equilibration with similar positive rates. PMID:29183966

High-frequency modes in a two-dimensional rectangular room with windows

NASA Astrophysics Data System (ADS)

Shabalina, E. D.; Shirgina, N. V.; Shanin, A. V.

2010-07-01

We examine a two-dimensional model problem of architectural acoustics on sound propagation in a rectangular room with windows. It is supposed that the walls are ideally flat and hard; the windows absorb all energy that falls upon them. We search for the modes of such a room having minimal attenuation indices, which have the expressed structure of billiard trajectories. The main attenuation mechanism for such modes is diffraction at the edges of the windows. We construct estimates for the attenuation indices of the given modes based on the solution to the Weinstein problem. We formulate diffraction problems similar to the statement of the Weinstein problem that describe the attenuation of billiard modes in complex situations.

Radial rescaling approach for the eigenvalue problem of a particle in an arbitrarily shaped box.

PubMed

Lijnen, Erwin; Chibotaru, Liviu F; Ceulemans, Arnout

2008-01-01

In the present work we introduce a methodology for solving a quantum billiard with Dirichlet boundary conditions. The procedure starts from the exactly known solutions for the particle in a circular disk, which are subsequently radially rescaled in such a way that they obey the new boundary conditions. In this way one constructs a complete basis set which can be used to obtain the eigenstates and eigenenergies of the corresponding quantum billiard to a high level of precision. Test calculations for several regular polygons show the efficiency of the method which often requires one or two basis functions to describe the lowest eigenstates with high accuracy.

Level statistics of a noncompact cosmological billiard

NASA Astrophysics Data System (ADS)

Csordas, Andras; Graham, Robert; Szepfalusy, Peter

1991-08-01

A noncompact chaotic billiard on a two-dimensional space of constant negative curvature, the infinite equilateral triangle describing anisotropy oscillations in the very early universe, is studied quantum-mechanically. A Weyl formula with a logarithmic correction term is derived for the smoothed number of states function. For one symmetry class of the eigenfunctions, the level spacing distribution, the spectral rigidity Delta3, and the Sigma2 statistics are determined numerically using the finite matrix approximation. Systematic deviations are found both from the Gaussian orthogonal ensemble (GOE) and the Poissonian ensemble. However, good agreement with the GOE is found if the fundamental triangle is deformed in such a way that it no longer tiles the space.

jsc2017e137344 - At the Cosmonaut Hotel crew quarters in Baikonur, Kazakhstan, Expedition 54-55 prime crewmember Anton Shkaplerov of the Russian Federal Space Agency (Roscosmos) tries his hand at a game of billiards Dec. 11 during a break in pre-launch tr

NASA Image and Video Library

2017-12-11

jsc2017e137344 - At the Cosmonaut Hotel crew quarters in Baikonur, Kazakhstan, Expedition 54-55 prime crewmember Anton Shkaplerov of the Russian Federal Space Agency (Roscosmos) tries his hand at a game of billiards Dec. 11 during a break in pre-launch training. Shkaplerov, Scott Tingle of NASA and Norishige Kanai of the Japan Aerospace Exploration Agency (JAXA) will launch Dec. 17 on the Soyuz MS-07 spacecraft from the Baikonur Cosmodrome for a five month mission on the International Space Station...Andrey Shelepin / Gagarin Cosmonaut Training Center.

On the Limiting Markov Process of Energy Exchanges in a Rarely Interacting Ball-Piston Gas

NASA Astrophysics Data System (ADS)

Bálint, Péter; Gilbert, Thomas; Nándori, Péter; Szász, Domokos; Tóth, Imre Péter

2017-02-01

We analyse the process of energy exchanges generated by the elastic collisions between a point-particle, confined to a two-dimensional cell with convex boundaries, and a `piston', i.e. a line-segment, which moves back and forth along a one-dimensional interval partially intersecting the cell. This model can be considered as the elementary building block of a spatially extended high-dimensional billiard modeling heat transport in a class of hybrid materials exhibiting the kinetics of gases and spatial structure of solids. Using heuristic arguments and numerical analysis, we argue that, in a regime of rare interactions, the billiard process converges to a Markov jump process for the energy exchanges and obtain the expression of its generator.

Characteristic dynamics near two coalescing eigenvalues incorporating continuum threshold effects

NASA Astrophysics Data System (ADS)

Garmon, Savannah; Ordonez, Gonzalo

2017-06-01

It has been reported in the literature that the survival probability P(t) near an exceptional point where two eigenstates coalesce should generally exhibit an evolution P (t ) ˜t2e-Γ t, in which Γ is the decay rate of the coalesced eigenstate; this has been verified in a microwave billiard experiment [B. Dietz et al., Phys. Rev. E 75, 027201 (2007)]. However, the heuristic effective Hamiltonian that is usually employed to obtain this result ignores the possible influence of the continuum threshold on the dynamics. By contrast, in this work we employ an analytical approach starting from the microscopic Hamiltonian representing two simple models in order to show that the continuum threshold has a strong influence on the dynamics near exceptional points in a variety of circumstances. To report our results, we divide the exceptional points in Hermitian open quantum systems into two cases: at an EP2A two virtual bound states coalesce before forming a resonance, anti-resonance pair with complex conjugate eigenvalues, while at an EP2B two resonances coalesce before forming two different resonances. For the EP2B, which is the case studied in the microwave billiard experiment, we verify that the survival probability exhibits the previously reported modified exponential decay on intermediate time scales, but this is replaced with an inverse power law on very long time scales. Meanwhile, for the EP2A the influence from the continuum threshold is so strong that the evolution is non-exponential on all time scales and the heuristic approach fails completely. When the EP2A appears very near the threshold, we obtain the novel evolution P (t ) ˜1 -C1√{t } on intermediate time scales, while further away the parabolic decay (Zeno dynamics) on short time scales is enhanced.

jsc2017e137338 - At the Cosmonaut Hotel crew quarters in Baikonur, Kazakhstan, Expedition 54-55 prime crewmember Norishige Kanai of the Japan Aerospace Exploration Agency (JAXA) tries his hand at a game of billiards Dec. 11 during a break in pre-launch tr

NASA Image and Video Library

2017-12-11

jsc2017e137338 - At the Cosmonaut Hotel crew quarters in Baikonur, Kazakhstan, Expedition 54-55 prime crewmember Norishige Kanai of the Japan Aerospace Exploration Agency (JAXA) tries his hand at a game of billiards Dec. 11 during a break in pre-launch training while backup crewmember Jeanette Epps of NASA looks on. Kanai, Scott Tingle of NASA and Anton Shkaplerov of the Russian Federal Space Agency (Roscosmos) will launch Dec. 17 on the Soyuz MS-07 spacecraft from the Baikonur Cosmodrome for a five month mission on the International Space Station...Andrey Shelepin / Gagarin Cosmonaut Training Center.

Error of semiclassical eigenvalues in the semiclassical limit - an asymptotic analysis of the Sinai billiard

NASA Astrophysics Data System (ADS)

Dahlqvist, Per

1999-10-01

We estimate the error in the semiclassical trace formula for the Sinai billiard under the assumption that the largest source of error is due to penumbra diffraction: namely, diffraction effects for trajectories passing within a distance Ricons/Journals/Common/cdot" ALT="cdot" ALIGN="TOP"/>O((kR)-2/3) to the disc and trajectories being scattered in very forward directions. Here k is the momentum and R the radius of the scatterer. The semiclassical error is estimated by perturbing the Berry-Keating formula. The analysis necessitates an asymptotic analysis of very long periodic orbits. This is obtained within an approximation originally due to Baladi, Eckmann and Ruelle. We find that the average error, for sufficiently large values of kR, will exceed the mean level spacing.

Arithmetic and Hyperbolic Structures in String Theory

NASA Astrophysics Data System (ADS)

Persson, Daniel

2010-01-01

This monograph is an updated and extended version of the author's PhD thesis. It consists of an introductory text followed by two separate parts which are loosely related but may be read independently of each other. In Part I we analyze certain hyperbolic structures arising when studying gravity in the vicinity of a spacelike singularity (the "BKL-limit"). In this limit, spatial points decouple and the dynamics exhibits ultralocal behaviour which may be described in terms of a (possibly chaotic) hyperbolic billiard. In all supergravities arising as low-energy limits of string theory or M-theory, the billiard dynamics takes place within the fundamental Weyl chambers of certain hyperbolic Kac-Moody algebras, suggesting that these algebras generate hidden infinite-dimensional symmetries of the theory. Part II of the thesis is devoted to a study of how (U-)dualities in string theory provide powerful constraints on perturbative and non-perturbative quantum corrections. These dualities are described by certain arithmetic groups G(Z) which are conjectured to be preserved in the effective action. The exact couplings are given by automorphic forms on the double quotient G(Z)G/K. We discuss in detail various methods of constructing automorphic forms, with particular emphasis on non-holomorphic Eisenstein series. We provide detailed examples for the physically relevant cases of SL(2,Z) and SL(3,Z), for which we construct their respective Eisenstein series and compute their (non-abelian) Fourier expansions. We also show how these techniques can be applied to hypermultiplet moduli spaces in type II Calabi-Yau compactifications, and we provide a detailed analysis for the universal hypermultiplet.

Playing relativistic billiards beyond graphene

NASA Astrophysics Data System (ADS)

Sadurní, E.; Seligman, T. H.; Mortessagne, F.

2010-05-01

The possibility of using hexagonal structures in general, and graphene in particular, to emulate the Dirac equation is the topic under consideration here. We show that Dirac oscillators with or without rest mass can be emulated by distorting a tight-binding model on a hexagonal structure. In the quest to make a toy model for such relativistic equations, we first show that a hexagonal lattice of attractive potential wells would be a good candidate. Firstly, we consider the corresponding one-dimensional (1D) model giving rise to a 1D Dirac oscillator and then construct explicitly the deformations needed in the 2D case. Finally, we discuss how such a model can be implemented as an electromagnetic billiard using arrays of dielectric resonators between two conducting plates that ensure evanescent modes outside the resonators for transversal electric modes, and we describe a feasible experimental setup.

Spectral Properties of Dirac Billiards at the van Hove Singularities.

PubMed

Dietz, B; Klaus, T; Miski-Oglu, M; Richter, A; Wunderle, M; Bouazza, C

2016-01-15

We study distributions of the ratios of level spacings of rectangular and Africa-shaped superconducting microwave resonators containing circular scatterers on a triangular grid, so-called Dirac billiards (DBs). The high-precision measurements allowed the determination of, respectively, all 1651 and 1823 eigenfrequencies in the first two bands. The resonance densities are similar to that of graphene. They exhibit two sharp peaks at the van Hove singularities which separate the band structure into regions with a linear and a quadratic dispersion relation, respectively. In the vicinity of the van Hove singularities we observe rapid changes in, e.g., the wave function structure. Accordingly, we question whether the spectral properties are there still determined by the shapes of the DBs. The commonly used statistical measures are no longer applicable; however, we demonstrate in this Letter that the ratio distributions provide suitable measures.

Quantum mushroom billiards

DOE Office of Scientific and Technical Information (OSTI.GOV)

Barnett, Alex H.; Betcke, Timo; School of Mathematics, University of Manchester, Manchester, M13 9PL

2007-12-15

We report the first large-scale statistical study of very high-lying eigenmodes (quantum states) of the mushroom billiard proposed by L. A. Bunimovich [Chaos 11, 802 (2001)]. The phase space of this mixed system is unusual in that it has a single regular region and a single chaotic region, and no KAM hierarchy. We verify Percival's conjecture to high accuracy (1.7%). We propose a model for dynamical tunneling and show that it predicts well the chaotic components of predominantly regular modes. Our model explains our observed density of such superpositions dying as E{sup -1/3} (E is the eigenvalue). We compare eigenvaluemore » spacing distributions against Random Matrix Theory expectations, using 16 000 odd modes (an order of magnitude more than any existing study). We outline new variants of mesh-free boundary collocation methods which enable us to achieve high accuracy and high mode numbers ({approx}10{sup 5}) orders of magnitude faster than with competing methods.« less

Transition from Poissonian to Gaussian-orthogonal-ensemble level statistics in a modified Artin's billiard

NASA Astrophysics Data System (ADS)

Csordás, A.; Graham, R.; Szépfalusy, P.; Vattay, G.

1994-01-01

One wall of an Artin's billiard on the Poincaré half-plane is replaced by a one-parameter (cp) family of nongeodetic walls. A brief description of the classical phase space of this system is given. In the quantum domain, the continuous and gradual transition from the Poisson-like to Gaussian-orthogonal-ensemble (GOE) level statistics due to the small perturbations breaking the symmetry responsible for the ``arithmetic chaos'' at cp=1 is studied. Another GOE-->Poisson transition due to the mixed phase space for large perturbations is also investigated. A satisfactory description of the intermediate level statistics by the Brody distribution was found in both cases. The study supports the existence of a scaling region around cp=1. A finite-size scaling relation for the Brody parameter as a function of 1-cp and the number of levels considered can be established.

BILLIARDS: A Demonstration Mission for Hundred-Meter Class Near-Earth Asteroid Disruption

NASA Technical Reports Server (NTRS)

Marcus, Matthew; Sloane, Joshua; Ortiz, Oliver; Barbee, Brent William

2015-01-01

Collisions from near-Earth asteroids (NEAs) have the potential to cause widespread harm to life on Earth. The hypervelocity nature of these collisions means that a relatively small asteroid (about a quartermile in diameter) could cause a global disaster. Proposed strategies for deflecting or disrupting such a threatening asteroid include detonation of a nuclear explosive device (NED) in close proximity to the asteroid, as well as intercepting the asteroid with a hypervelocity kinetic impactor. NEDs allow for the delivery of large amounts of energy to a NEA for a given mass launched from the Earth, but have not yet been developed or tested for use in deep space. They also present safety and political complications, and therefore may only be used when absolutely necessary. Kinetic impactors require a relatively simple spacecraft compared to NEDs, but also deliver a much lower energy for a given launch mass. To date, no demonstration mission has been conducted for either case, and such a demonstration mission must be conducted prior to the need to utilize them during an actual scenario to ensure that an established, proven system is available for planetary defense when the need arises. One method that has been proposed to deliver a kinetic impactor with impact energy approaching that of an NED is the "billiard-ball" approach. This approach would involve capturing an asteroid approximately ten meters in diameter with a relatively small spacecraft (compared to the launch mass of an equivalent direct kinetic impactor), and redirecting it into the path of an Earth-threatening asteroid. This would cause an impact which would disrupt the Earth-threatening asteroid or deflect it from its Earth-crossing trajectory. The BILLIARDS Project seeks to perform a demonstration of this mission concept in order to establish a protocol that can be used in the event of an impending Earth/asteroid collision. In order to accomplish this objective, the mission must (1) rendezvous with a small (less than 10m), NEA (hereinafter "Alpha"), (2) maneuver Alpha to a collision with a approx. 100 m NEA (hereinafter "Beta"), and (3) produce a detectable deflection or disruption of Beta. In addition to these primary objectives, the BILLIARDS project will contribute to the scientific understanding of the physical properties and collision dynamics of asteroids, and provide opportunities for international collaboration.

Basic modelling of transport in 2D wave-mechanical nanodots and billiards with balanced gain and loss mediated by complex potentials

NASA Astrophysics Data System (ADS)

Berggren, Karl-Fredrik; Tellander, Felix; Yakimenko, Irina

2018-05-01

Non-Hermitian quantum mechanics with parity-time (PT) symmetry is presently gaining great interest, especially within the fields of photonics and optics. Here, we give a brief overview of low-dimensional semiconductor nanodevices using the example of a quantum dot with input and output leads, which are mimicked by imaginary potentials for gain and loss, and how wave functions, particle flow, coalescence of levels and associated breaking of PT symmetry may be analysed within such a framework. Special attention is given to the presence of exceptional points and symmetry breaking. Related features for musical string instruments and ‘wolf-notes’ are outlined briefly with suggestions for further experiments.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zanetti, F.M.; Vicentini, E.; Luz, M.G.E. da

It was proposed about a decade ago [M.G.E. da Luz, A.S. Lupu-Sax, E.J. Heller, Phys. Rev. E 56 (1997) 2496] a simple approach for obtaining scattering states for arbitrary disconnected open or closed boundaries C, with different boundary conditions. Since then, the so called boundary wall method has been successfully used to solve different open boundary problems. However, its applicability to closed shapes has not been fully explored. In this contribution we present a complete account of how to use the boundary wall to the case of billiard systems. We review the general ideas and particularize them to single connectedmore » closed shapes, assuming Dirichlet boundary conditions for the C's. We discuss the mathematical aspects that lead to both the inside and outside solutions. We also present a different way to calculate the exterior scattering S matrix. From it, we revisit the important inside-outside duality for billiards. Finally, we give some numerical examples, illustrating the efficiency and flexibility of the method to treat this type of problem.« less

BILLIARDS: A Demonstration Mission for Hundred-Meter Class Near Earth Asteroid Disruption

NASA Technical Reports Server (NTRS)

Marcus, Matthew; Sloane, Joshua; Ortiz, Oliver; Barbee, Brent W.

2015-01-01

Currently, no planetary defense demonstration mission has ever been flown. While Nuclear Explosive Devices (NEDs) have significantly more energy than a kinetic impactor launched directly from Earth, they present safety and political complications, and therefore may only be used when absolutely necessary. The Baseline Instrumented Lithology Lander, Inspector, and Asteroid Redirection Demonstration System (BILLIARDS) is a demonstration mission for planetary defense, which is capable of delivering comparable energy to the lower range of NED capabilities in the form of a safer kinetic impactor. A small asteroid (<10m) is captured by a spacecraft, which greatly increases the mass available as a kinetic impactor, without the need to bring all of the mass out of Earth's gravity well. The small asteroid is then deflected onto a collision course with a larger (approx. 100m) asteroid. This collision will deflect or disrupt the larger asteroid. To reduce the cost and complexity, an asteroid pair which has a natural close approach is selected.

Stickiness in Hamiltonian systems: From sharply divided to hierarchical phase space

NASA Astrophysics Data System (ADS)

Altmann, Eduardo G.; Motter, Adilson E.; Kantz, Holger

2006-02-01

We investigate the dynamics of chaotic trajectories in simple yet physically important Hamiltonian systems with nonhierarchical borders between regular and chaotic regions with positive measures. We show that the stickiness to the border of the regular regions in systems with such a sharply divided phase space occurs through one-parameter families of marginally unstable periodic orbits and is characterized by an exponent γ=2 for the asymptotic power-law decay of the distribution of recurrence times. Generic perturbations lead to systems with hierarchical phase space, where the stickiness is apparently enhanced due to the presence of infinitely many regular islands and Cantori. In this case, we show that the distribution of recurrence times can be composed of a sum of exponentials or a sum of power laws, depending on the relative contribution of the primary and secondary structures of the hierarchy. Numerical verification of our main results are provided for area-preserving maps, mushroom billiards, and the newly defined magnetic mushroom billiards.

Anomalous heat conduction and anomalous diffusion in nonlinear lattices, single walled nanotubes, and billiard gas channels.

PubMed

Li, Baowen; Wang, Jiao; Wang, Lei; Zhang, Gang

2005-03-01

We study anomalous heat conduction and anomalous diffusion in low-dimensional systems ranging from nonlinear lattices, single walled carbon nanotubes, to billiard gas channels. We find that in all discussed systems, the anomalous heat conductivity can be connected with the anomalous diffusion, namely, if energy diffusion is sigma(2)(t)=2Dt(alpha) (01) implies an anomalous heat conduction with a divergent thermal conductivity (beta>0), and more interestingly, a subdiffusion (alpha<1) implies an anomalous heat conduction with a convergent thermal conductivity (beta<0), consequently, the system is a thermal insulator in the thermodynamic limit. Existing numerical data support our theoretical prediction.

Equation of state of an ideal gas with nonergodic behavior in two connected vessels.

PubMed

Naplekov, D M; Semynozhenko, V P; Yanovsky, V V

2014-01-01

We consider a two-dimensional collisionless ideal gas in the two vessels connected through a small hole. One of them is a well-behaved chaotic billiard, another one is known to be nonergodic. A significant part of the second vessel's phase space is occupied by an island of stability. In the works of Zaslavsky and coauthors, distribution of Poincaré recurrence times in similar systems was considered. We study the gas pressure in the vessels; it is uniform in the first vessel and not uniform in second one. An equation of the gas state in the first vessel is obtained. Despite the very different phase-space structure, behavior of the second vessel is found to be very close to the behavior of a good ergodic billiard but of different volume. The equation of state differs from the ordinary equation of ideal gas state by an amendment to the vessel's volume. Correlation of this amendment with a share of the phase space under remaining intact islands of stability is shown.

29 CFR 779.320 - Partial list of establishments whose sales or service may be recognized as retail.

Code of Federal Regulations, 2014 CFR

2014-07-01

.... Antique shops. Auto courts. Automobile dealers' establishments. Automobile laundries. Automobile repair shops. Barber shops. Beauty shops. Bicycle shops. Billiard parlors. Book stores. Bowling alleys. Butcher shops. Cafeterias. Cemeteries. China, glassware stores. Cigar stores. Clothing stores. Coal yards...

29 CFR 779.320 - Partial list of establishments whose sales or service may be recognized as retail.

Code of Federal Regulations, 2011 CFR

2011-07-01

.... Antique shops. Auto courts. Automobile dealers' establishments. Automobile laundries. Automobile repair shops. Barber shops. Beauty shops. Bicycle shops. Billiard parlors. Book stores. Bowling alleys. Butcher shops. Cafeterias. Cemeteries. China, glassware stores. Cigar stores. Clothing stores. Coal yards...

29 CFR 779.320 - Partial list of establishments whose sales or service may be recognized as retail.

Code of Federal Regulations, 2013 CFR

2013-07-01

.... Antique shops. Auto courts. Automobile dealers' establishments. Automobile laundries. Automobile repair shops. Barber shops. Beauty shops. Bicycle shops. Billiard parlors. Book stores. Bowling alleys. Butcher shops. Cafeterias. Cemeteries. China, glassware stores. Cigar stores. Clothing stores. Coal yards...

29 CFR 779.320 - Partial list of establishments whose sales or service may be recognized as retail.

Code of Federal Regulations, 2012 CFR

2012-07-01

.... Antique shops. Auto courts. Automobile dealers' establishments. Automobile laundries. Automobile repair shops. Barber shops. Beauty shops. Bicycle shops. Billiard parlors. Book stores. Bowling alleys. Butcher shops. Cafeterias. Cemeteries. China, glassware stores. Cigar stores. Clothing stores. Coal yards...

29 CFR 779.320 - Partial list of establishments whose sales or service may be recognized as retail.

Code of Federal Regulations, 2010 CFR

2010-07-01

.... Antique shops. Auto courts. Automobile dealers' establishments. Automobile laundries. Automobile repair shops. Barber shops. Beauty shops. Bicycle shops. Billiard parlors. Book stores. Bowling alleys. Butcher shops. Cafeterias. Cemeteries. China, glassware stores. Cigar stores. Clothing stores. Coal yards...

15. Photocopy of 1872 photograph by Eadweard Muybridge in Stanford ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

15. Photocopy of 1872 photograph by Eadweard Muybridge in Stanford University Archives, PC 6. BASEMENT BILLIARD ROOM, LOOKING SOUTH. LEFT TO RIGHT, LELAND STANFORD, JR., MRS. LELAND STANFORD AND ANNA MARIA LATHROP (MRS. STANFORD'S SISTER) - Leland Stanford House, 800 N Street, Sacramento, Sacramento County, CA

13. Historic American Buildings Survey, August, 1971 VIEW OF EAST ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

13. Historic American Buildings Survey, August, 1971 VIEW OF EAST SIDE OF OREGON STREET SHOWING MASONIC BUILDING (FAR LEFT) (HABS NO. ORE-100), TABLE ROCK BILLIARD SALOON (HABS NO. ORE-123), MCCULLY BUILDING (T.O.O.F. LODGE) (HABS NO. ORE-102). - Jacksonville Historic District, Jacksonville, Jackson County, OR

How Physics is Used in Video Games

ERIC Educational Resources Information Center

Bourg, David M.

2004-01-01

Modern video games use physics to achieve realistic behaviour and special effects. Everything from billiard balls, to flying debris, to tactical fighter jets is simulated in games using fundamental principles of dynamics. This article explores several examples of how physics is used in games. Further, this article describes some of the more…

Dissecting Success Stories on Mathematical Problem Posing: A Case of the Billiard Task

ERIC Educational Resources Information Center

Koichu, Boris; Kontorovich, Igor

2013-01-01

"Success stories," i.e., cases in which mathematical problems posed in a controlled setting are perceived by the problem posers or other individuals as interesting, cognitively demanding, or surprising, are essential for understanding the nature of problem posing. This paper analyzes two success stories that occurred with individuals of different…

In vitro culture and rooting of Diospyros virginiana L.

Treesearch

Kaitlin J. Palla; Rochelle R. Beasley; Paula M. Pijut

2013-01-01

The hard, strong, very close-grained wood of common persimmon (Diospyros virginiana L.; Ebenaceae) is desirable for specialty products such as golf club heads, percussion sticks, billiard cues, and for wood turnery. The edible fruit of cultivated varieties is sold as pulp for use in puddings, cookies, cakes, and custards. Persimmon is usually...

The Essence of Cooperation: Establishing a Framework for Success in Military Regimes

DTIC Science & Technology

2015-06-01

illustrate this point, Krasner rejects the conventional realist’s billiard ball analogy in favor of an image of tectonic plates . In this metaphor...regimes and states act as the plates in contact with one another, putting pressure on each other over time and moving at different rates of speed.43

Compound Poisson Law for Hitting Times to Periodic Orbits in Two-Dimensional Hyperbolic Systems

NASA Astrophysics Data System (ADS)

Carney, Meagan; Nicol, Matthew; Zhang, Hong-Kun

2017-11-01

We show that a compound Poisson distribution holds for scaled exceedances of observables φ uniquely maximized at a periodic point ζ in a variety of two-dimensional hyperbolic dynamical systems with singularities (M,T,μ ), including the billiard maps of Sinai dispersing billiards in both the finite and infinite horizon case. The observable we consider is of form φ (z)=-ln d(z,ζ ) where d is a metric defined in terms of the stable and unstable foliation. The compound Poisson process we obtain is a Pólya-Aeppli distibution of index θ . We calculate θ in terms of the derivative of the map T. Furthermore if we define M_n=\\max {φ ,\\ldots ,φ circ T^n} and u_n (τ ) by \\lim _{n→ ∞} nμ (φ >u_n (τ ) )=τ the maximal process satisfies an extreme value law of form μ (M_n ≤ u_n)=e^{-θ τ }. These results generalize to a broader class of functions maximized at ζ , though the formulas regarding the parameters in the distribution need to be modified.

Rotation in a gravitational billiard

NASA Astrophysics Data System (ADS)

Peraza-Mues, G. G.; Carvente, Osvaldo; Moukarzel, Cristian F.

Gravitational billiards composed of a viscoelastic frictional disk bouncing on a vibrating wedge have been studied previously, but only from the point of view of their translational behavior. In this work, the average rotational velocity of the disk is studied under various circumstances. First, an experimental realization is briefly presented, which shows sustained rotation when the wedge is tilted. Next, this phenomenon is scrutinized in close detail using a precise numerical implementation of frictional forces. We show that the bouncing disk acquires a spontaneous rotational velocity whenever the wedge angle is not bisected by the direction of gravity. Our molecular dynamics (MD) results are well reproduced by event-driven (ED) simulations. When the wedge aperture angle θW>π/2, the average tangential velocity Rω¯ of the disk scales with the typical wedge vibration velocity vb, and is in general a nonmonotonic function of the overall tilt angle θT of the wedge. The present work focuses on wedges with θW=2π/3, which are relevant for the problem of spontaneous rotation in vibrated disk packings. This study makes part of the PhD Thesis of G. G. Peraza-Mues.

Indoor air pollution (PM2.5) due to secondhand smoke in selected hospitality and entertainment venues of Karachi, Pakistan.

PubMed

Nafees, Asaad Ahmed; Taj, Tahir; Kadir, Muhammad Masood; Fatmi, Zafar; Lee, Kiyoung; Sathiakumar, Nalini

2012-09-01

To determine particulate matter smaller than 2.5 μm (PM(2.5)) levels at various hospitality and entertainment venues of Karachi, Pakistan. This was a descriptive cross-sectional study conducted at various locations in Karachi, during July 2009. Sampling was performed at 20 enclosed public places, including hospitality (restaurants and cafés) and entertainment (snooker/billiard clubs and gaming zones) venues. PM(2.5) levels were measured using an aerosol monitor. All entertainment venues had higher indoor PM(2.5) levels as compared to the immediate outdoors. The indoor PM(2.5) levels ranged from 25 to 390 μg/m(3) and the outdoor PM(2.5) levels ranged from 18 to 96 μg/m(3). The overall mean indoor PM(2.5) level was 138.8 μg/m(3) (± 112.8). Among the four types of venues, the highest mean indoor PM(2.5) level was reported from snooker/billiard clubs: 264.7 μg/m(3) (± 85.4) and the lowest from restaurants: 66.4 μg/m(3) (± 57.6) while the indoor/outdoor ratio ranged from 0.97 to 10.2, highest being at the snooker/billiard clubs. The smoking density ranged from 0.21 to 0.57, highest being at gaming zones. The indoor PM(2.5) concentration and smoking density were not significantly correlated (Spearman's correlation coefficient = 0.113; p = 0.636). This study demonstrates unacceptably high levels of PM(2.5) exposure associated with secondhand smoke (SHS) at various entertainment venues of Karachi even after 8 years since the promulgation of smoke-free ordinance (2002) in Pakistan; however, better compliance may be evident at hospitality venues. The results of this study call for effective implementation and enforcement of smoke-free environment at public places in the country.

On the statistical and transport properties of a non-dissipative Fermi-Ulam model

NASA Astrophysics Data System (ADS)

Livorati, André L. P.; Dettmann, Carl P.; Caldas, Iberê L.; Leonel, Edson D.

2015-10-01

The transport and diffusion properties for the velocity of a Fermi-Ulam model were characterized using the decay rate of the survival probability. The system consists of an ensemble of non-interacting particles confined to move along and experience elastic collisions with two infinitely heavy walls. One is fixed, working as a returning mechanism of the colliding particles, while the other one moves periodically in time. The diffusion equation is solved, and the diffusion coefficient is numerically estimated by means of the averaged square velocity. Our results show remarkably good agreement of the theory and simulation for the chaotic sea below the first elliptic island in the phase space. From the decay rates of the survival probability, we obtained transport properties that can be extended to other nonlinear mappings, as well to billiard problems.

The Power of Likeness: But Analogy Can Take Us Only So Far.

ERIC Educational Resources Information Center

Filonovich, S. R.

1991-01-01

Describes the use of analogy relative to the classical theory of momentum and kinetic energy, and addresses the advantages and disadvantages of this approach with respect to modern physics. Discusses the origins of the billiard ball analogy in the work of Coriolis and its influence on later theories and investigations of nuclear fission, particle…

The Hardest Straight-in Pool Shot

ERIC Educational Resources Information Center

Mabry, Rick

2010-01-01

When playing pool or billiards, a player often has the opportunity to make a "straight-in" shot, that is, one in which the cue ball, the object ball, and the target (e.g., a pocket) are collinear. With the distance from the cue ball to the target assumed fixed, the relative difficulty is here explored of shots taken at varying positions of the…

Multiple Scattering in Random Mechanical Systems and Diffusion Approximation

NASA Astrophysics Data System (ADS)

Feres, Renato; Ng, Jasmine; Zhang, Hong-Kun

2013-10-01

This paper is concerned with stochastic processes that model multiple (or iterated) scattering in classical mechanical systems of billiard type, defined below. From a given (deterministic) system of billiard type, a random process with transition probabilities operator P is introduced by assuming that some of the dynamical variables are random with prescribed probability distributions. Of particular interest are systems with weak scattering, which are associated to parametric families of operators P h , depending on a geometric or mechanical parameter h, that approaches the identity as h goes to 0. It is shown that ( P h - I)/ h converges for small h to a second order elliptic differential operator on compactly supported functions and that the Markov chain process associated to P h converges to a diffusion with infinitesimal generator . Both P h and are self-adjoint (densely) defined on the space of square-integrable functions over the (lower) half-space in , where η is a stationary measure. This measure's density is either (post-collision) Maxwell-Boltzmann distribution or Knudsen cosine law, and the random processes with infinitesimal generator respectively correspond to what we call MB diffusion and (generalized) Legendre diffusion. Concrete examples of simple mechanical systems are given and illustrated by numerically simulating the random processes.

Periodic orbit spectrum in terms of Ruelle-Pollicott resonances

NASA Astrophysics Data System (ADS)

Leboeuf, P.

2004-02-01

Fully chaotic Hamiltonian systems possess an infinite number of classical solutions which are periodic, e.g., a trajectory “p” returns to its initial conditions after some fixed time τp. Our aim is to investigate the spectrum {τ1,τ2,…} of periods of the periodic orbits. An explicit formula for the density ρ(τ)=∑pδ(τ-τp) is derived in terms of the eigenvalues of the classical evolution operator. The density is naturally decomposed into a smooth part plus an interferent sum over oscillatory terms. The frequencies of the oscillatory terms are given by the imaginary part of the complex eigenvalues (Ruelle-Pollicott resonances). For large periods, corrections to the well-known exponential growth of the smooth part of the density are obtained. An alternative formula for ρ(τ) in terms of the zeros and poles of the Ruelle ζ function is also discussed. The results are illustrated with the geodesic motion in billiards of constant negative curvature. Connections with the statistical properties of the corresponding quantum eigenvalues, random-matrix theory, and discrete maps are also considered. In particular, a random-matrix conjecture is proposed for the eigenvalues of the classical evolution operator of chaotic billiards.

Quantum Ergodicity and L p Norms of Restrictions of Eigenfunctions

NASA Astrophysics Data System (ADS)

Hezari, Hamid

2018-02-01

We prove an analogue of Sogge's local L p estimates for L p norms of restrictions of eigenfunctions to submanifolds, and use it to show that for quantum ergodic eigenfunctions one can get improvements of the results of Burq-Gérard-Tzvetkov, Hu, and Chen-Sogge. The improvements are logarithmic on negatively curved manifolds (without boundary) and by o(1) for manifolds (with or without boundary) with ergodic geodesic flows. In the case of ergodic billiards with piecewise smooth boundary, we get o(1) improvements on L^∞ estimates of Cauchy data away from a shrinking neighborhood of the corners, and as a result using the methods of Ghosh et al., Jung and Zelditch, Jung and Zelditch, we get that the number of nodal domains of 2-dimensional ergodic billiards tends to infinity as λ \\to ∞. These results work only for a full density subsequence of any given orthonormal basis of eigenfunctions. We also present an extension of the L p estimates of Burq-Gérard-Tzvetkov, Hu, Chen-Sogge for the restrictions of Dirichlet and Neumann eigenfunctions to compact submanifolds of the interior of manifolds with piecewise smooth boundary. This part does not assume ergodicity on the manifolds.

Hearing shapes of drums: Mathematical and physical aspects of isospectrality

DOE Office of Scientific and Technical Information (OSTI.GOV)

Giraud, Olivier; Thas, Koen; LPT

2010-07-15

In a celebrated paper ''Can one hear the shape of a drum?'' M. Kac [Am. Math. Monthly 73, 1 (1966)] asked his famous question about the existence of nonisometric billiards having the same spectrum of the Laplacian. This question was eventually answered positively in 1992 by the construction of noncongruent planar isospectral pairs. This review highlights mathematical and physical aspects of isospectrality.

Singularities and non-hyperbolic manifolds do not coincide

NASA Astrophysics Data System (ADS)

Simányi, Nándor

2013-06-01

We consider the billiard flow of elastically colliding hard balls on the flat ν-torus (ν ⩾ 2), and prove that no singularity manifold can even locally coincide with a manifold describing future non-hyperbolicity of the trajectories. As a corollary, we obtain the ergodicity (actually the Bernoulli mixing property) of all such systems, i.e. the verification of the Boltzmann-Sinai ergodic hypothesis.

Stochastic Processes in Physics: Deterministic Origins and Control

NASA Astrophysics Data System (ADS)

Demers, Jeffery

Stochastic processes are ubiquitous in the physical sciences and engineering. While often used to model imperfections and experimental uncertainties in the macroscopic world, stochastic processes can attain deeper physical significance when used to model the seemingly random and chaotic nature of the underlying microscopic world. Nowhere more prevalent is this notion than in the field of stochastic thermodynamics - a modern systematic framework used describe mesoscale systems in strongly fluctuating thermal environments which has revolutionized our understanding of, for example, molecular motors, DNA replication, far-from equilibrium systems, and the laws of macroscopic thermodynamics as they apply to the mesoscopic world. With progress, however, come further challenges and deeper questions, most notably in the thermodynamics of information processing and feedback control. Here it is becoming increasingly apparent that, due to divergences and subtleties of interpretation, the deterministic foundations of the stochastic processes themselves must be explored and understood. This thesis presents a survey of stochastic processes in physical systems, the deterministic origins of their emergence, and the subtleties associated with controlling them. First, we study time-dependent billiards in the quivering limit - a limit where a billiard system is indistinguishable from a stochastic system, and where the simplified stochastic system allows us to view issues associated with deterministic time-dependent billiards in a new light and address some long-standing problems. Then, we embark on an exploration of the deterministic microscopic Hamiltonian foundations of non-equilibrium thermodynamics, and we find that important results from mesoscopic stochastic thermodynamics have simple microscopic origins which would not be apparent without the benefit of both the micro and meso perspectives. Finally, we study the problem of stabilizing a stochastic Brownian particle with feedback control, and we find that in order to avoid paradoxes involving the first law of thermodynamics, we need a model for the fine details of the thermal driving noise. The underlying theme of this thesis is the argument that the deterministic microscopic perspective and stochastic mesoscopic perspective are both important and useful, and when used together, we can more deeply and satisfyingly understand the physics occurring over either scale.

Closed almost-periodic orbits in semiclassical quantization of generic polygons

PubMed

Biswas

2000-05-01

Periodic orbits are the central ingredients of modern semiclassical theories and corrections to these are generally nonclassical in origin. We show here that, for the class of generic polygonal billiards, the corrections are predominantly classical in origin owing to the contributions from closed almost-periodic (CAP) orbit families. Furthermore, CAP orbit families outnumber periodic families but have comparable weights. They are hence indispensable for semiclassical quantization.

Contrasting Views of Complexity and Their Implications For Network-Centric Infrastructures

DTIC Science & Technology

2010-07-04

problem) can be undecidable. While two gravitationally interacting bodies yield simple orbits, Poincare showed that the motion of even three...statistical me- chanics are valid only when the [billiard] balls are distributed, in their positions and motions , in a helter-skelter, i.e., a disorga- nized...Rube Goldberg, whose famous cartoons depict “ comically involved complicated invention[s], laboriously contrived to perform a simple operation” [68

A Research on Mathematical Thinking Skills: Mathematical Thinking Skills of Athletes in Individual and Team Sports

ERIC Educational Resources Information Center

Onal, Halil; Inan, Mehmet; Bozkurt, Sinan

2017-01-01

The aim of this research is to examine the mathematical thinking skills of licensed athletes engaged in individual and team sports. The research is designed as a survey model. The sample of the research is composed of 59 female and 170 male licensed athletes (n = 229) and (aged 14 to 52) licensed who do the sports of shooting, billiards, archery,…

Diffraction catastrophes and semiclassical quantum mechanics for Veselago lensing in graphene

NASA Astrophysics Data System (ADS)

Reijnders, K. J. A.; Katsnelson, M. I.

2017-07-01

We study the effect of trigonal warping on the focusing of electrons by n-p junctions in graphene. We find that perfect focusing, which was predicted for massless Dirac fermions, is only preserved for one specific lattice orientation. In the general case, trigonal warping leads to the formation of cusp caustics, with a different position of the focus for graphene's two valleys. We develop a semiclassical theory to compute these positions and find very good agreement with tight-binding simulations. Considering the transmission as a function of potential strength, we find that trigonal warping splits the single Dirac peak into two distinct peaks, leading to valley polarization. We obtain the transmission curves from tight-binding simulations and find that they are in very good agreement with the results of a billiard model that incorporates trigonal warping. Furthermore, the positions of the transmission maxima and the scaling of the peak width are accurately predicted by our semiclassical theory. Our semiclassical analysis can easily be carried over to other Dirac materials, which generally have different Fermi surface distortions.

Experimental phase-space-based optical amplification of scar modes.

PubMed

Michel, C; Tascu, S; Doya, V; Aschiéri, P; Blanc, W; Legrand, O; Mortessagne, F

2012-04-01

Wave billiards which are chaotic in the geometrical limit are known to support nongeneric spatially localized modes called scar modes. The interaction of the scar modes with gain has been recently investigated in optics in microcavity lasers and vertical-cavity surface-emitting lasers. Exploiting the localization properties of scar modes in their wave-analogous phase-space representation, we report experimental results of scar mode selection by gain in a doped D-shaped optical fiber.

Physics of croquet

NASA Astrophysics Data System (ADS)

Cross, Rod

2017-01-01

Croquet is a sport that is similar to billiards in that it involves the collision of one ball with another. Measurements and calculations are presented for three typical shots, one known as a straight croquet, one known as a split croquet and the other known as a push or roll shot. Each exhibit collision phenomena that could serve to illustrate aspects of an introductory course in mechanics, and that could also provide challenges even for more advanced students.

Integration of a vision-based tracking platform, visual instruction, and error analysis models for an efficient billiard training system

NASA Astrophysics Data System (ADS)

Shih, Chihhsiong; Hsiung, Pao-Ann; Wan, Chieh-Hao; Koong, Chorng-Shiuh; Liu, Tang-Kun; Yang, Yuanfan; Lin, Chu-Hsing; Chu, William Cheng-Chung

2009-02-01

A billiard ball tracking system is designed to combine with a visual guide interface to instruct users for a reliable strike. The integrated system runs on a PC platform. The system makes use of a vision system for cue ball, object ball and cue stick tracking. A least-squares error calibration process correlates the real-world and the virtual-world pool ball coordinates for a precise guidance line calculation. Users are able to adjust the cue stick on the pool table according to a visual guidance line instruction displayed on a PC monitor. The ideal visual guidance line extended from the cue ball is calculated based on a collision motion analysis. In addition to calculating the ideal visual guide, the factors influencing selection of the best shot among different object balls and pockets are explored. It is found that a tolerance angle around the ideal line for the object ball to roll into a pocket determines the difficulty of a strike. This angle depends in turn on the distance from the pocket to the object, the distance from the object to the cue ball, and the angle between these two vectors. Simulation results for tolerance angles as a function of these quantities are given. A selected object ball was tested extensively with respect to various geometrical parameters with and without using our integrated system. Players with different proficiency levels were selected for the experiment. The results indicate that all players benefit from our proposed visual guidance system in enhancing their skills, while low-skill players show the maximum enhancement in skill with the help of our system. All exhibit enhanced maximum and average hit-in rates. Experimental results on hit-in rates have shown a pattern consistent with that of the analysis. The hit-in rate is thus tightly connected with the analyzed tolerance angles for sinking object balls into a target pocket. These results prove the efficiency of our system, and the analysis results can be used to attain an efficient game-playing strategy.

Experimental investigation of linear and nonlinear wave systems: A quantum chaos approach

NASA Astrophysics Data System (ADS)

Neicu, Toni

2002-09-01

An experimental and numerical study of linear and nonlinear wave systems using methods and ideas developed from quantum chaos is presented. We exploit the analogy of the wave equation for the flexural modes of a thin clover-shaped acoustic plate to the stationary solutions of the Schrodinger wave equation for a quantum clover-shaped billiard, a generic system that has regular and chaotic regions in its phase space. We observed periodic orbits in the spectral properties of the acoustic plate, the first such definitive acoustic experiment. We also solved numerically the linear wave equation of the acoustic plate for the first few hundred eigenmodes. The Fourier transform of the eigenvalues show peaks corresponding to the principal periodic orbits of the classical billiard. The signatures of the periodic orbits in the spectra were unambiguously verified by deforming one edge of the plate and observing that only the peaks corresponding to the orbits that hit this edge changed. The statistical measures of the eigenvalues are intermediate between universal forms for completely integrable and chaotic systems. The density distribution of the eigenfunctions agrees with the Porter-Thomas formula of chaotic systems. The viscosity dependence and effects of nonlinearity on the Faraday surface wave patterns in a stadium geometry were also investigated. The ray dynamics inside the stadium, a paradigm of quantum chaos, is completely chaotic. The majority of the observed patterns of the orbits resemble three eigenstates of the stadium: the bouncing ball, longitudinal, and bowtie patterns. We observed many disordered patterns that increase with the viscosity. The experimental results were analyzed using recent theoretical work that explains the suppression of certain modes. The theory also predicts that the perimeter dissipation is too strong for whispering gallery modes, which contradicts our observations of these modes for a fluid with low viscosity. Novel vortex patterns were observed in a strongly nonlinear, dissipative granular system of vertically vibrated rods. Above a critical packing fraction, moving domains of nearly vertical rods were seen to coexist with horizontal rods. The vertical domains coarsen to form several large vortices, which were driven by the anisotropy and inclination of the rods.

Mr Tompkins in Paperback

NASA Astrophysics Data System (ADS)

Gamow, George; Penrose, Foreword by Roger

2012-03-01

Foreword Roger Penrose; 1. City speed limit; 2. The Professor's lecture on relativity which caused Mr Tompkins's dream; 3. Mr Tompkins takes a holiday; 4. The Professor's lecture on curved space, gravity and the universe; 5. The pulsating universe; 6. Cosmic opera; 7. Quantum billiards; 8. Quantum jungles; 9. Maxwell's demon; 10. The gay tribe of electrons; 10 1/2. A part of the previous lecture which Mr Tompkins slept through; 12. Inside the nucleus; 13. The wood carver; 14. Holes in nothing; 15. Mr Tompkins tastes a Japanese meal.

Wave Chaos and HPM Effects on Electronic Systems

DTIC Science & Technology

2013-08-13

if one examines these pas- sages, one will find that, as the orbit length approaches infinity, (i) the fraction of time spent by the orbit in the...as the orbits in a complete quarter circle billiard having the same radius R (see Fig. 3.2(a)). These orbits are tangent to a circular caustic 62 with...a radius Cr. If the caustic radius Cr > ρ0, (see Fig. 3.1) this orbit is trapped in the cap, and is integrable. There are also chaotic orbits that

The DARPA compact superconducting x-ray lithography source features. [Defense Advanced Research Projects Agency (DARPA)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Heese, R.; Kalsi, S.; Leung, E.

1991-01-01

Under DARPA sponsorship, a compact Superconducting X-ray Lithography Source (SXLS) is being designed and built by the Brookhaven National Laboratory (BNL) with industry participation from Grumman Corporation and General Dynamics. This source is optimized for lithography work for sub-micron high density computer chips, and is about the size of a billiard table (1.5 m {times} 4.0 m). The machine has a racetrack configuration with two 180{degree} bending magnets being designed and built by General Dynamics under a subcontract with Grumman Corporation. The machine will have 18 photon ports which would deliver light peaked at a wave length of 10 Angstroms.more » Grumman is commercializing the SXLS device and plans to book orders for delivery of industrialized SXLS (ISXLS) versions in 1995. This paper will describe the major features of this device. The commercial machine will be equipped with a fully automated user-friendly control systems, major features of which are already working on a compact warm dipole ring at BNL. This ring has normal dipole magnets with dimensions identical to the SXLS device, and has been successfully commissioned. 4 figs., 1 tab.« less

Periodic Orbits Contribution to the 2-Point Correlation Form Factor for Pseudo-Integrable Systems

NASA Astrophysics Data System (ADS)

Bogomolny, E.; Giraud, O.; Schmit, C.

Using heuristic arguments based on the trace formulas we relate the 2-point correlation form factor, K2(τ), at small values of τ with sums over classical periodic orbits for typical examples of pseudo-integrable systems. The later sums have been explicitly calculated for the following models: (i) plane billiards in the form of right triangles with one angle π/n and (ii) rectangular billiards with the Aharonov-Bohm flux line. In the first model, using the properties of the Veech structure, it is shown that K2(0)=(n+ɛ(n))/(3(n-2)), where ɛ(n)= 0 for odd n, ɛ(n)= 2 for even n not divisible by 3, and ɛ(n)=6 for even n divisible by 3. For completeness we also recall informally the main features of the Veech construction. In the second model the answer depends on arithmetical properties of ratios of flux line coordinates to the corresponding sides of the rectangle. When these ratios are non-commensurable irrational numbers, K2(0)=1-3 , where is the fractional part of the flux through the rectangle when and it is symmetric with respect to the line when . The comparison of these results with numerical calculations of the form factor is discussed in detail. The above values of K2(0) differ from all known examples of spectral statistics, thus confirming analytically the peculiarities of statistical properties of the energy levels in pseudo-integrable systems.

Expedition 43 Media Day

NASA Image and Video Library

2015-03-21

Media document Expedition 43 NASA Astronaut Scott Kelly as he plays billiards during media day, Saturday, March 21, 2015, Baikonur, Kazakhstan. Kelly, and Russian Cosmonauts Gennady Padalka, and Mikhail Kornienko of the Russian Federal Space Agency (Roscosmos) are scheduled to launch to the International Space Station in the Soyuz TMA-16M spacecraft from the Baikonur Cosmodrome in Kazakhstan March 28, Kazakh time (March 27 Eastern time.) As the one-year crew, Kelly and Kornienko will return to Earth on Soyuz TMA-18M in March 2016. Photo Credit: (NASA/Bill Ingalls)

Exponential energy growth due to slow parameter oscillations in quantum mechanical systems.

PubMed

Turaev, Dmitry

2016-05-01

It is shown that a periodic emergence and destruction of an additional quantum number leads to an exponential growth of energy of a quantum mechanical system subjected to a slow periodic variation of parameters. The main example is given by systems (e.g., quantum billiards and quantum graphs) with periodically divided configuration space. In special cases, the process can also lead to a long period of cooling that precedes the acceleration, and to the desertion of the states with a particular value of the quantum number.

Characteristics of level-spacing statistics in chaotic graphene billiards.

PubMed

Huang, Liang; Lai, Ying-Cheng; Grebogi, Celso

2011-03-01

A fundamental result in nonrelativistic quantum nonlinear dynamics is that the spectral statistics of quantum systems that possess no geometric symmetry, but whose classical dynamics are chaotic, are described by those of the Gaussian orthogonal ensemble (GOE) or the Gaussian unitary ensemble (GUE), in the presence or absence of time-reversal symmetry, respectively. For massless spin-half particles such as neutrinos in relativistic quantum mechanics in a chaotic billiard, the seminal work of Berry and Mondragon established the GUE nature of the level-spacing statistics, due to the combination of the chirality of Dirac particles and the confinement, which breaks the time-reversal symmetry. A question is whether the GOE or the GUE statistics can be observed in experimentally accessible, relativistic quantum systems. We demonstrate, using graphene confinements in which the quasiparticle motions are governed by the Dirac equation in the low-energy regime, that the level-spacing statistics are persistently those of GOE random matrices. We present extensive numerical evidence obtained from the tight-binding approach and a physical explanation for the GOE statistics. We also find that the presence of a weak magnetic field switches the statistics to those of GUE. For a strong magnetic field, Landau levels become influential, causing the level-spacing distribution to deviate markedly from the random-matrix predictions. Issues addressed also include the effects of a number of realistic factors on level-spacing statistics such as next nearest-neighbor interactions, different lattice orientations, enhanced hopping energy for atoms on the boundary, and staggered potential due to graphene-substrate interactions.

Rebounding droplet-droplet collisions on superhydrophobic surfaces: from the phenomenon to droplet logic.

PubMed

Mertaniemi, Henrikki; Forchheimer, Robert; Ikkala, Olli; Ras, Robin H A

2012-11-08

When water droplets impact each other while traveling on a superhydrophobic surface, we demonstrate that they are able to rebound like billiard balls. We present elementary Boolean logic operations and a flip-flop memory based on these rebounding water droplet collisions. Furthermore, bouncing or coalescence can be easily controlled by process parameters. Thus by the controlled coalescence of reactive droplets, here using the quenching of fluorescent metal nanoclusters as a model reaction, we also demonstrate an elementary operation for programmable chemistry. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Microwave fidelity studies by varying antenna coupling

NASA Astrophysics Data System (ADS)

Köber, B.; Kuhl, U.; Stöckmann, H.-J.; Gorin, T.; Savin, D. V.; Seligman, T. H.

2010-09-01

The fidelity decay in a microwave billiard is considered, where the coupling to an attached antenna is varied. The resulting quantity, coupling fidelity, is experimentally studied for three different terminators of the varied antenna: a hard-wall reflection, an open wall reflection, and a 50Ω load, corresponding to a totally open channel. The model description in terms of an effective Hamiltonian with a complex coupling constant is given. Quantitative agreement is found with the theory obtained from a modified VWZ approach [J. J. M. Verbaarschot , Phys. Rep. 129, 367 (1985)10.1016/0370-1573(85)90070-5].

Slow relaxation in weakly open rational polygons.

PubMed

Kokshenev, Valery B; Vicentini, Eduardo

2003-07-01

The interplay between the regular (piecewise-linear) and irregular (vertex-angle) boundary effects in nonintegrable rational polygonal billiards (of m equal sides) is discussed. Decay dynamics in polygons (of perimeter P(m) and small opening Delta) is analyzed through the late-time survival probability S(m) approximately equal t(-delta). Two distinct slow relaxation channels are established. The primary universal channel exhibits relaxation of regular sliding orbits, with delta=1. The secondary channel is given by delta>1 and becomes open when m>P(m)/Delta. It originates from vertex order-disorder dual effects and is due to relaxation of chaoticlike excitations.

Integrable model for density-modulated quantum condensates: Solitons passing through a soliton lattice.

PubMed

Takahashi, Daisuke A

2016-06-01

An integrable model possessing inhomogeneous ground states is proposed as an effective model of nonuniform quantum condensates such as supersolids and Fulde-Ferrell-Larkin-Ovchinnikov superfluids. The model is a higher-order analog of the nonlinear Schrödinger equation. We derive an n-soliton solution via the inverse scattering theory with elliptic-functional background and reveal various kinds of soliton dynamics such as dark soliton billiards, dislocations, gray solitons, and envelope solitons. We also provide the exact bosonic and fermionic quasiparticle eigenstates and show their tunneling phenomena. The solutions are expressed by a determinant of theta functions.

Expedition 43 Media Day

NASA Image and Video Library

2015-03-21

Media document Expedition 43 Russian Cosmonaut Mikhail Kornienko of the Russian Federal Space Agency (Roscosmos), left, and NASA Astronaut Scott Kelly, right, as they play billiards during media day, Saturday, March 21, 2015, Baikonur, Kazakhstan. Kelly, and Russian Cosmonauts Gennady Padalka, and Mikhail Kornienko of Roscosmos are scheduled to launch to the International Space Station in the Soyuz TMA-16M spacecraft from the Baikonur Cosmodrome in Kazakhstan March 28, Kazakh time (March 27 Eastern time.) As the one-year crew, Kelly and Kornienko will return to Earth on Soyuz TMA-18M in March 2016. Photo Credit: (NASA/Bill Ingalls)

Chaotic Ising-like dynamics in traffic signals

PubMed Central

Suzuki, Hideyuki; Imura, Jun-ichi; Aihara, Kazuyuki

2013-01-01

The green and red lights of a traffic signal can be viewed as the up and down states of an Ising spin. Moreover, traffic signals in a city interact with each other, if they are controlled in a decentralised way. In this paper, a simple model of such interacting signals on a finite-size two-dimensional lattice is shown to have Ising-like dynamics that undergoes a ferromagnetic phase transition. Probabilistic behaviour of the model is realised by chaotic billiard dynamics that arises from coupled non-chaotic elements. This purely deterministic model is expected to serve as a starting point for considering statistical mechanics of traffic signals. PMID:23350034

Deterministic Approach to the Kinetic Theory of Gases

NASA Astrophysics Data System (ADS)

Beck, József

2010-02-01

In the so-called Bernoulli model of the kinetic theory of gases, where (1) the particles are dimensionless points, (2) they are contained in a cube container, (3) no attractive or exterior forces are acting on them, (4) there is no collision between the particles, (5) the collision against the walls of the container are according to the law of elastic reflection, we deduce from Newtonian mechanics two local probabilistic laws: a Poisson limit law and a central limit theorem. We also prove some global law of large numbers, justifying that "density" and "pressure" are constant. Finally, as a byproduct of our research, we prove the surprising super-uniformity of the typical billiard path in a square.

jsc2014e049621

NASA Image and Video Library

2014-05-21

11-47-48: At the Cosmonaut Hotel crew quarters in Baikonur, Kazakhstan, Expedition 40/41 backup crewmembers Terry Virts of NASA (left) and Samantha Cristoforetti of the European Space Agency (right) try their hand at a game of billiards May 21 as they head into the homestretch of pre-launch training. Virts, Cristoforetti and Anton Shkaplerov of the Russian Federal Space Agency (Roscosmos) are backing up the prime crew, Flight Engineer Alexander Gerst of the European Space Agency, Soyuz Commander Max Suraev of Roscosmos and NASA Flight Engineer Reid Wiseman, who will launch on May 29, Kazakh time, on the Soyuz TMA-13M spacecraft from the Baikonur Cosmodrome for a 5 ½ month mission on the International Space Station. NASA/Victor Zelentsov

Imaging chemical reactions - 3D velocity mapping

NASA Astrophysics Data System (ADS)

Chichinin, A. I.; Gericke, K.-H.; Kauczok, S.; Maul, C.

Visualising a collision between an atom or a molecule or a photodissociation (half-collision) of a molecule on a single particle and single quantum level is like watching the collision of billiard balls on a pool table: Molecular beams or monoenergetic photodissociation products provide the colliding reactants at controlled velocity before the reaction products velocity is imaged directly with an elaborate camera system, where one should keep in mind that velocity is, in general, a three-dimensional (3D) vectorial property which combines scattering angles and speed. If the processes under study have no cylindrical symmetry, then only this 3D product velocity vector contains the full information of the elementary process under study.

Experimental evidence of coherent transport.

PubMed

Flores-Olmedo, E; Martínez-Argüello, A M; Martínez-Mares, M; Báez, G; Franco-Villafañe, J A; Méndez-Sánchez, R A

2016-04-28

Coherent transport phenomena are difficult to observe due to several sources of decoherence. For instance, in the electronic transport through quantum devices the thermal smearing and dephasing, the latter induced by inelastic scattering by phonons or impurities, destroy phase coherence. In other wave systems, the temperature and dephasing may not destroy the coherence and can then be used to observe the underlying wave behaviour of the coherent phenomena. Here, we observe coherent transmission of mechanical waves through a two-dimensional elastic Sinai billiard with two waveguides. The flexural-wave transmission, performed by non-contact means, shows the quantization when a new mode becomes open. These measurements agree with the theoretical predictions of the simplest model highlighting the universal character of the transmission fluctuations.

Experimental evidence of coherent transport

PubMed Central

Flores-Olmedo, E.; Martínez-Argüello, A. M.; Martínez-Mares, M.; Báez, G.; Franco-Villafañe, J. A.; Méndez-Sánchez, R. A.

2016-01-01

Coherent transport phenomena are difficult to observe due to several sources of decoherence. For instance, in the electronic transport through quantum devices the thermal smearing and dephasing, the latter induced by inelastic scattering by phonons or impurities, destroy phase coherence. In other wave systems, the temperature and dephasing may not destroy the coherence and can then be used to observe the underlying wave behaviour of the coherent phenomena. Here, we observe coherent transmission of mechanical waves through a two-dimensional elastic Sinai billiard with two waveguides. The flexural-wave transmission, performed by non-contact means, shows the quantization when a new mode becomes open. These measurements agree with the theoretical predictions of the simplest model highlighting the universal character of the transmission fluctuations. PMID:27121226

Chaos-assisted tunneling in the presence of Anderson localization.

PubMed

Doggen, Elmer V H; Georgeot, Bertrand; Lemarié, Gabriel

2017-10-01

Tunneling between two classically disconnected regular regions can be strongly affected by the presence of a chaotic sea in between. This phenomenon, known as chaos-assisted tunneling, gives rise to large fluctuations of the tunneling rate. Here we study chaos-assisted tunneling in the presence of Anderson localization effects in the chaotic sea. Our results show that the standard tunneling rate distribution is strongly modified by localization, going from the Cauchy distribution in the ergodic regime to a log-normal distribution in the strongly localized case, for both a deterministic and a disordered model. We develop a single-parameter scaling description which accurately describes the numerical data. Several possible experimental implementations using cold atoms, photonic lattices, or microwave billiards are discussed.

Topological classification of the Goryachev integrable case in rigid body dynamics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nikolaenko, S S

2016-01-31

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

Displacement Cascade Damage Production in Metals

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stoller, Roger E; Malerba, Lorenzo; Nordlund, Kai

Radiation-induced changes in microstructure and mechanical properties in structural materials are the result of a complex set of physical processes initiated by the collision between an energetic particle (neutron or ion) and an atom in the lattice. This primary damage event is called an atomic displacement cascade. The simplest description of a displacement cascade is to view it as a series of many billiard-ball-like elastic collisions among the atoms in the material. This chapter describes the formation and evolution of this primary radiation damage mechanism to provide an overview of how stable defects are formed by displacement cascades, as wellmore » as the nature and morphology of the defects themselves. The impact of the relevant variables such as cascade energy and irradiation temperature is discussed, and defect formation in different materials is compared.« less

Global workspace dynamics: cortical "binding and propagation" enables conscious contents.

PubMed

Baars, Bernard J; Franklin, Stan; Ramsoy, Thomas Zoega

2013-01-01

A global workspace (GW) is a functional hub of binding and propagation in a population of loosely coupled signaling elements. In computational applications, GW architectures recruit many distributed, specialized agents to cooperate in resolving focal ambiguities. In the brain, conscious experiences may reflect a GW function. For animals, the natural world is full of unpredictable dangers and opportunities, suggesting a general adaptive pressure for brains to resolve focal ambiguities quickly and accurately. GW theory aims to understand the differences between conscious and unconscious brain events. In humans and related species the cortico-thalamic (C-T) core is believed to underlie conscious aspects of perception, thinking, learning, feelings of knowing (FOK), felt emotions, visual imagery, working memory, and executive control. Alternative theoretical perspectives are also discussed. The C-T core has many anatomical hubs, but conscious percepts are unitary and internally consistent at any given moment. Over time, conscious contents constitute a very large, open set. This suggests that a brain-based GW capacity cannot be localized in a single anatomical hub. Rather, it should be sought in a functional hub - a dynamic capacity for binding and propagation of neural signals over multiple task-related networks, a kind of neuronal cloud computing. In this view, conscious contents can arise in any region of the C-T core when multiple input streams settle on a winner-take-all equilibrium. The resulting conscious gestalt may ignite an any-to-many broadcast, lasting ∼100-200 ms, and trigger widespread adaptation in previously established networks. To account for the great range of conscious contents over time, the theory suggests an open repertoire of binding coalitions that can broadcast via theta/gamma or alpha/gamma phase coupling, like radio channels competing for a narrow frequency band. Conscious moments are thought to hold only 1-4 unrelated items; this small focal capacity may be the biological price to pay for global access. Visuotopic maps in cortex specialize in features like color, retinal size, motion, object identity, and egocentric/allocentric framing, so that a binding coalition for the sight of a rolling billiard ball in nearby space may resonate among activity maps of LGN, V1-V4, MT, IT, as well as the dorsal stream. Spatiotopic activity maps can bind into coherent gestalts using adaptive resonance (reentry). Single neurons can join a dominant coalition by phase tuning to regional oscillations in the 4-12 Hz range. Sensory percepts may bind and broadcast from posterior cortex, while non-sensory FOKs may involve prefrontal and frontotemporal areas. The anatomy and physiology of the hippocampal complex suggest a GW architecture as well. In the intact brain the hippocampal complex may support conscious event organization as well as episodic memory storage.

Global Workspace Dynamics: Cortical “Binding and Propagation” Enables Conscious Contents

PubMed Central

Baars, Bernard J.; Franklin, Stan; Ramsoy, Thomas Zoega

2013-01-01

A global workspace (GW) is a functional hub of binding and propagation in a population of loosely coupled signaling elements. In computational applications, GW architectures recruit many distributed, specialized agents to cooperate in resolving focal ambiguities. In the brain, conscious experiences may reflect a GW function. For animals, the natural world is full of unpredictable dangers and opportunities, suggesting a general adaptive pressure for brains to resolve focal ambiguities quickly and accurately. GW theory aims to understand the differences between conscious and unconscious brain events. In humans and related species the cortico-thalamic (C-T) core is believed to underlie conscious aspects of perception, thinking, learning, feelings of knowing (FOK), felt emotions, visual imagery, working memory, and executive control. Alternative theoretical perspectives are also discussed. The C-T core has many anatomical hubs, but conscious percepts are unitary and internally consistent at any given moment. Over time, conscious contents constitute a very large, open set. This suggests that a brain-based GW capacity cannot be localized in a single anatomical hub. Rather, it should be sought in a functional hub – a dynamic capacity for binding and propagation of neural signals over multiple task-related networks, a kind of neuronal cloud computing. In this view, conscious contents can arise in any region of the C-T core when multiple input streams settle on a winner-take-all equilibrium. The resulting conscious gestalt may ignite an any-to-many broadcast, lasting ∼100–200 ms, and trigger widespread adaptation in previously established networks. To account for the great range of conscious contents over time, the theory suggests an open repertoire of binding1 coalitions that can broadcast via theta/gamma or alpha/gamma phase coupling, like radio channels competing for a narrow frequency band. Conscious moments are thought to hold only 1–4 unrelated items; this small focal capacity may be the biological price to pay for global access. Visuotopic maps in cortex specialize in features like color, retinal size, motion, object identity, and egocentric/allocentric framing, so that a binding coalition for the sight of a rolling billiard ball in nearby space may resonate among activity maps of LGN, V1-V4, MT, IT, as well as the dorsal stream. Spatiotopic activity maps can bind into coherent gestalts using adaptive resonance (reentry). Single neurons can join a dominant coalition by phase tuning to regional oscillations in the 4–12 Hz range. Sensory percepts may bind and broadcast from posterior cortex, while non-sensory FOKs may involve prefrontal and frontotemporal areas. The anatomy and physiology of the hippocampal complex suggest a GW architecture as well. In the intact brain the hippocampal complex may support conscious event organization as well as episodic memory storage. PMID:23974723

Diffractive paths for weak localization in quantum billiards

NASA Astrophysics Data System (ADS)

Březinová, Iva; Stampfer, Christoph; Wirtz, Ludger; Rotter, Stefan; Burgdörfer, Joachim

2008-04-01

We study the weak-localization effect in quantum transport through a clean ballistic cavity with regular classical dynamics. We address the question which paths account for the suppression of conductance through a system where disorder and chaos are absent. By exploiting both quantum and semiclassical methods, we unambiguously identify paths that are diffractively backscattered into the cavity (when approaching the lead mouths from the cavity interior) to play a key role. Diffractive scattering couples transmitted and reflected paths and is thus essential to reproduce the weak-localization peak in reflection and the corresponding antipeak in transmission. A comparison of semiclassical calculations featuring these diffractive paths yields good agreement with full quantum calculations and experimental data. Our theory provides system-specific predictions for the quantum regime of few open lead modes and can be expected to be relevant also for mixed as well as chaotic systems.

Principles of Discrete Time Mechanics

NASA Astrophysics Data System (ADS)

Jaroszkiewicz, George

2014-04-01

1. Introduction; 2. The physics of discreteness; 3. The road to calculus; 4. Temporal discretization; 5. Discrete time dynamics architecture; 6. Some models; 7. Classical cellular automata; 8. The action sum; 9. Worked examples; 10. Lee's approach to discrete time mechanics; 11. Elliptic billiards; 12. The construction of system functions; 13. The classical discrete time oscillator; 14. Type 2 temporal discretization; 15. Intermission; 16. Discrete time quantum mechanics; 17. The quantized discrete time oscillator; 18. Path integrals; 19. Quantum encoding; 20. Discrete time classical field equations; 21. The discrete time Schrodinger equation; 22. The discrete time Klein-Gordon equation; 23. The discrete time Dirac equation; 24. Discrete time Maxwell's equations; 25. The discrete time Skyrme model; 26. Discrete time quantum field theory; 27. Interacting discrete time scalar fields; 28. Space, time and gravitation; 29. Causality and observation; 30. Concluding remarks; Appendix A. Coherent states; Appendix B. The time-dependent oscillator; Appendix C. Quaternions; Appendix D. Quantum registers; References; Index.

The ergodicity landscape of quantum theories

NASA Astrophysics Data System (ADS)

Ho, Wen Wei; Radičević, Đorđe

2018-02-01

This paper is a physicist’s review of the major conceptual issues concerning the problem of spectral universality in quantum systems. Here, we present a unified, graph-based view of all archetypical models of such universality (billiards, particles in random media, interacting spin or fermion systems). We find phenomenological relations between the onset of ergodicity (Gaussian-random delocalization of eigenstates) and the structure of the appropriate graphs, and we construct a heuristic picture of summing trajectories on graphs that describes why a generic interacting system should be ergodic. We also provide an operator-based discussion of quantum chaos and propose criteria to distinguish bases that can usefully diagnose ergodicity. The result of this analysis is a rough but systematic outline of how ergodicity changes across the space of all theories with a given Hilbert space dimension. As a particular example, we study the SYK model and report on the transition from maximal to partial ergodicity as the disorder strength is decreased.

Quantum chaos and breaking of all anti-unitary symmetries in Rydberg excitons.

PubMed

Aßmann, Marc; Thewes, Johannes; Fröhlich, Dietmar; Bayer, Manfred

2016-07-01

Symmetries are the underlying principles of fundamental interactions in nature. Chaos in a quantum system may emerge from breaking these symmetries. Compared to vacuum, crystals are attractive for studying quantum chaos, as they not only break spatial isotropy, but also lead to novel quasiparticles with modified interactions. Here we study yellow Rydberg excitons in cuprous oxide which couple strongly to the vacuum light field and interact significantly with crystal phonons, leading to inversion symmetry breaking. In a magnetic field, time-reversal symmetry is also broken and the exciton states show a complex splitting pattern, resulting in quadratic level repulsion for small splittings. In contrast to atomic chaotic systems in a magnetic field, which show only a linear level repulsion, this is a signature of a system where all anti-unitary symmetries are broken simultaneously. This behaviour can otherwise be found only for the electro-weak interaction or engineered billiards.

Code C# for chaos analysis of relativistic many-body systems

NASA Astrophysics Data System (ADS)

Grossu, I. V.; Besliu, C.; Jipa, Al.; Bordeianu, C. C.; Felea, D.; Stan, E.; Esanu, T.

2010-08-01

This work presents a new Microsoft Visual C# .NET code library, conceived as a general object oriented solution for chaos analysis of three-dimensional, relativistic many-body systems. In this context, we implemented the Lyapunov exponent and the “fragmentation level” (defined using the graph theory and the Shannon entropy). Inspired by existing studies on billiard nuclear models and clusters of galaxies, we tried to apply the virial theorem for a simplified many-body system composed by nucleons. A possible application of the “virial coefficient” to the stability analysis of chaotic systems is also discussed. Catalogue identifier: AEGH_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEGH_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.: 30 053 No. of bytes in distributed program, including test data, etc.: 801 258 Distribution format: tar.gz Programming language: Visual C# .NET 2005 Computer: PC Operating system: .Net Framework 2.0 running on MS Windows Has the code been vectorized or parallelized?: Each many-body system is simulated on a separate execution thread RAM: 128 Megabytes Classification: 6.2, 6.5 External routines: .Net Framework 2.0 Library Nature of problem: Chaos analysis of three-dimensional, relativistic many-body systems. Solution method: Second order Runge-Kutta algorithm for simulating relativistic many-body systems. Object oriented solution, easy to reuse, extend and customize, in any development environment which accepts .Net assemblies or COM components. Implementation of: Lyapunov exponent, “fragmentation level”, “average system radius”, “virial coefficient”, and energy conservation precision test. Additional comments: Easy copy/paste based deployment method. Running time: Quadratic complexity.

Experiments in Computing: A Survey

PubMed Central

Moisseinen, Nella

2014-01-01

Experiments play a central role in science. The role of experiments in computing is, however, unclear. Questions about the relevance of experiments in computing attracted little attention until the 1980s. As the discipline then saw a push towards experimental computer science, a variety of technically, theoretically, and empirically oriented views on experiments emerged. As a consequence of those debates, today's computing fields use experiments and experiment terminology in a variety of ways. This paper analyzes experimentation debates in computing. It presents five ways in which debaters have conceptualized experiments in computing: feasibility experiment, trial experiment, field experiment, comparison experiment, and controlled experiment. This paper has three aims: to clarify experiment terminology in computing; to contribute to disciplinary self-understanding of computing; and, due to computing's centrality in other fields, to promote understanding of experiments in modern science in general. PMID:24688404

Experiments in computing: a survey.

PubMed

Tedre, Matti; Moisseinen, Nella

2014-01-01

Experiments play a central role in science. The role of experiments in computing is, however, unclear. Questions about the relevance of experiments in computing attracted little attention until the 1980s. As the discipline then saw a push towards experimental computer science, a variety of technically, theoretically, and empirically oriented views on experiments emerged. As a consequence of those debates, today's computing fields use experiments and experiment terminology in a variety of ways. This paper analyzes experimentation debates in computing. It presents five ways in which debaters have conceptualized experiments in computing: feasibility experiment, trial experiment, field experiment, comparison experiment, and controlled experiment. This paper has three aims: to clarify experiment terminology in computing; to contribute to disciplinary self-understanding of computing; and, due to computing's centrality in other fields, to promote understanding of experiments in modern science in general.

Near-integrable behaviour in a family of discretized rotations

NASA Astrophysics Data System (ADS)

Reeve-Black, Heather; Vivaldi, Franco

2013-05-01

We consider a one-parameter family of invertible maps of a two-dimensional lattice, obtained by discretizing the space of planar rotations. We let the angle of rotation approach π/2, and show that the limit of vanishing discretization is described by an integrable piecewise-smooth Hamiltonian flow, whereby the plane foliates into families of invariant polygons with an increasing number of sides. Considered as perturbations of the flow, the lattice maps assume a different character, described in terms of strip maps, a variant of those found in outer billiards of polygons. The perturbation introduces phenomena reminiscent of the Kolmogorov-Arnold-Moser scenario: a positive fraction of the unperturbed curves survives. We prove this for symmetric orbits, under a condition that allows us to obtain explicit values for their density, the latter being a rational number typically less than 1. This result allows us to conclude that the infimum of the density of all surviving curves—symmetric or not—is bounded away from zero.

Universal Hitting Time Statistics for Integrable Flows

NASA Astrophysics Data System (ADS)

Dettmann, Carl P.; Marklof, Jens; Strömbergsson, Andreas

2017-02-01

The perceived randomness in the time evolution of "chaotic" dynamical systems can be characterized by universal probabilistic limit laws, which do not depend on the fine features of the individual system. One important example is the Poisson law for the times at which a particle with random initial data hits a small set. This was proved in various settings for dynamical systems with strong mixing properties. The key result of the present study is that, despite the absence of mixing, the hitting times of integrable flows also satisfy universal limit laws which are, however, not Poisson. We describe the limit distributions for "generic" integrable flows and a natural class of target sets, and illustrate our findings with two examples: the dynamics in central force fields and ellipse billiards. The convergence of the hitting time process follows from a new equidistribution theorem in the space of lattices, which is of independent interest. Its proof exploits Ratner's measure classification theorem for unipotent flows, and extends earlier work of Elkies and McMullen.

Fuchsian triangle groups and Grothendieck dessins. Variations on a theme of Belyi

NASA Astrophysics Data System (ADS)

Cohen, Paula Beazley; Itzykson, Claude; Wolfart, Jürgen

1994-07-01

According to a theorem of Belyi, a smooth projective algebraic curve is defined over a number field if and only if there exists a non-constant element of its function field ramified only over 0, 1 and . The existence of such a Belyi function is equivalent to that of a representation of the curve as a possibly compactified quotient space of the Poincaré upper half plane by a subgroup of finite index in a Fuchsian triangle group. On the other hand, Fuchsian triangle groups arise in many contexts, such as in the theory of hypergeometric functions and certain triangular billiard problems, which would appear at first sight to have no relation to the Galois problems that motivated the above discovery of Belyi. In this note we review several results related to Belyi's theorem and we develop certain aspects giving examples. For preliminary accounts, see the preprint [Wo1], the conference proceedings article [BauItz] and the Comptes Rendus note [CoWo2].

The Relationship Between Computer Experience and Computerized Cognitive Test Performance Among Older Adults

PubMed Central

2013-01-01

Objective. This study compared the relationship between computer experience and performance on computerized cognitive tests and a traditional paper-and-pencil cognitive test in a sample of older adults (N = 634). Method. Participants completed computer experience and computer attitudes questionnaires, three computerized cognitive tests (Useful Field of View (UFOV) Test, Road Sign Test, and Stroop task) and a paper-and-pencil cognitive measure (Trail Making Test). Multivariate analysis of covariance was used to examine differences in cognitive performance across the four measures between those with and without computer experience after adjusting for confounding variables. Results. Although computer experience had a significant main effect across all cognitive measures, the effect sizes were similar. After controlling for computer attitudes, the relationship between computer experience and UFOV was fully attenuated. Discussion. Findings suggest that computer experience is not uniquely related to performance on computerized cognitive measures compared with paper-and-pencil measures. Because the relationship between computer experience and UFOV was fully attenuated by computer attitudes, this may imply that motivational factors are more influential to UFOV performance than computer experience. Our findings support the hypothesis that computer use is related to cognitive performance, and this relationship is not stronger for computerized cognitive measures. Implications and directions for future research are provided. PMID:22929395

Sources of computer self-efficacy: The relationship to outcome expectations, computer anxiety, and intention to use computers

NASA Astrophysics Data System (ADS)

Antoine, Marilyn V.

2011-12-01

The purpose of this research was to extend earlier research on sources of selfefficacy (Lent, Lopez, & Biechke, 1991; Usher & Pajares, 2009) to the information technology domain. The principal investigator examined how Bandura's (1977) sources of self-efficacy information---mastery experience, vicarious experience, verbal persuasion, and physiological states---shape computer self-efficacy beliefs and influence the decision to use or not use computers. The study took place at a mid-sized Historically Black College or University in the South. A convenience sample of 105 undergraduates was drawn from students enrolled in multiple sections of two introductory computer courses. There were 67 females and 38 males. This research was a correlational study of the following variables: sources of computer self-efficacy, general computer self-efficacy, outcome expectations, computer anxiety, and intention to use computers. The principal investigator administered a survey questionnaire containing 52 Likert items to measure the major study variables. Additionally, the survey instrument collected demographic variables such as gender, age, race, intended major, classification, technology use, technology adoption category, and whether the student owns a computer. The results reveal the following: (1) Mastery experience and verbal persuasion had statistically significant relationships to general computer self-efficacy, while vicarious experience and physiological states had non-significant relationships. Mastery experience had the strongest correlation to general computer self-efficacy. (2) All of the sources of computer self-efficacy had statistically significant relationships to personal outcome expectations. Vicarious experience had the strongest correlation to personal outcome expectations. (3) All of the sources of self-efficacy had statistically significant relationships to performance outcome expectations. Vicarious experience had the strongest correlation to performance outcome expectations. (4) Mastery experience and physiological states had statistically significant relationships to computer anxiety, while vicarious experience and verbal persuasion had non-significant relationships. Physiological states had the strongest correlation to computer anxiety. (5) Mastery experience, vicarious experience, and physiological states had statistically significant relationships to intention to use computers, while verbal persuasion had a non-significant relationship. Mastery experience had the strongest correlation to intention to use computers. Gender-related findings indicate that females reported higher average mastery experience, vicarious experience, physiological states, and intention to use computers than males. Females reported lower average general computer self-efficacy, computer anxiety, verbal persuasion, personal outcome expectations, and performance outcome expectations than males. The results of this study can be used to develop strategies for increasing general computer self-efficacy, outcome expectations, and intention to use computers. The results can also be used to develop strategies for reducing computer anxiety.

Progress on the Fabric for Frontier Experiments Project at Fermilab

NASA Astrophysics Data System (ADS)

Box, Dennis; Boyd, Joseph; Dykstra, Dave; Garzoglio, Gabriele; Herner, Kenneth; Kirby, Michael; Kreymer, Arthur; Levshina, Tanya; Mhashilkar, Parag; Sharma, Neha

2015-12-01

The FabrIc for Frontier Experiments (FIFE) project is an ambitious, major-impact initiative within the Fermilab Scientific Computing Division designed to lead the computing model for Fermilab experiments. FIFE is a collaborative effort between experimenters and computing professionals to design and develop integrated computing models for experiments of varying needs and infrastructure. The major focus of the FIFE project is the development, deployment, and integration of Open Science Grid solutions for high throughput computing, data management, database access and collaboration within experiment. To accomplish this goal, FIFE has developed workflows that utilize Open Science Grid sites along with dedicated and commercial cloud resources. The FIFE project has made significant progress integrating into experiment computing operations several services including new job submission services, software and reference data distribution through CVMFS repositories, flexible data transfer client, and access to opportunistic resources on the Open Science Grid. The progress with current experiments and plans for expansion with additional projects will be discussed. FIFE has taken a leading role in the definition of the computing model for Fermilab experiments, aided in the design of computing for experiments beyond Fermilab, and will continue to define the future direction of high throughput computing for future physics experiments worldwide.

News | Computing

Science.gov Websites

Support News Publications Computing for Experiments Computing for Neutrino and Muon Physics Computing for Collider Experiments Computing for Astrophysics Research and Development Accelerator Modeling ComPASS - Impact of Detector Simulation on Particle Physics Collider Experiments Daniel Elvira's paper "Impact

Progress on the FabrIc for Frontier Experiments project at Fermilab

DOE PAGES

Box, Dennis; Boyd, Joseph; Dykstra, Dave; ...

2015-12-23

The FabrIc for Frontier Experiments (FIFE) project is an ambitious, major-impact initiative within the Fermilab Scientific Computing Division designed to lead the computing model for Fermilab experiments. FIFE is a collaborative effort between experimenters and computing professionals to design and develop integrated computing models for experiments of varying needs and infrastructure. The major focus of the FIFE project is the development, deployment, and integration of Open Science Grid solutions for high throughput computing, data management, database access and collaboration within experiment. To accomplish this goal, FIFE has developed workflows that utilize Open Science Grid sites along with dedicated and commercialmore » cloud resources. The FIFE project has made significant progress integrating into experiment computing operations several services including new job submission services, software and reference data distribution through CVMFS repositories, flexible data transfer client, and access to opportunistic resources on the Open Science Grid. Hence, the progress with current experiments and plans for expansion with additional projects will be discussed. FIFE has taken a leading role in the definition of the computing model for Fermilab experiments, aided in the design of computing for experiments beyond Fermilab, and will continue to define the future direction of high throughput computing for future physics experiments worldwide« less

Breaking time reversal in a simple smooth chaotic system.

PubMed

Tomsovic, Steven; Ullmo, Denis; Nagano, Tatsuro

2003-06-01

Within random matrix theory, the statistics of the eigensolutions depend fundamentally on the presence (or absence) of time reversal symmetry. Accepting the Bohigas-Giannoni-Schmit conjecture, this statement extends to quantum systems with chaotic classical analogs. For practical reasons, much of the supporting numerical studies of symmetry breaking have been done with billiards or maps, and little with simple, smooth systems. There are two main difficulties in attempting to break time reversal invariance in a continuous time system with a smooth potential. The first is avoiding false time reversal breaking. The second is locating a parameter regime in which the symmetry breaking is strong enough to transform the fluctuation properties fully to the broken symmetry case, and yet remain weak enough so as not to regularize the dynamics sufficiently that the system is no longer chaotic. We give an example of a system of two coupled quartic oscillators whose energy level statistics closely match with those of the Gaussian unitary ensemble, and which possesses only a minor proportion of regular motion in its phase space.

Foundations of Space and Time

NASA Astrophysics Data System (ADS)

Murugan, Jeff; Weltman, Amanda; Ellis, George F. R.

2012-07-01

1. The problem with quantum gravity Jeff Murugan, Amanda Weltman and George F. R. Eliis; 2. A dialogue on the nature of gravity Thanu Padmanabhan; 3. Effective theories and modifications of gravity Cliff Burgess; 4. The small scale structure of spacetime Steve Carlip; 5. Ultraviolet divergences in supersymmetric theories Kellog Stelle; 6. Cosmological quantum billiards Axel Kleinschmidt and Hermann Nicolai; 7. Progress in RNS string theory and pure spinors Dimitri Polyakov; 8. Recent trends in superstring phenomenology Massimo Bianchi; 9. Emergent spacetime Robert de Mello Koch and Jeff Murugan; 10. Loop quantum gravity Hanno Sahlmann; 11. Loop quantum gravity and cosmology Martin Bojowald; 12. The microscopic dynamics of quantum space as a group field theory Daniele Oriti; 13. Causal dynamical triangulations and the quest for quantum gravity Jan Ambjørn, J. Jurkiewicz and Renate Loll; 14. Proper time is stochastic time in 2D quantum gravity Jan Ambjorn, Renate Loll, Y. Watabiki, W. Westra and S. Zohren; 15. Logic is to the quantum as geometry is to gravity Rafael Sorkin; 16. Causal sets: discreteness without symmetry breaking Joe Henson; 17. The Big Bang, quantum gravity, and black-hole information loss Roger Penrose; Index.

Direct extraction of electron parameters from magnetoconductance analysis in mesoscopic ring array structures

NASA Astrophysics Data System (ADS)

Sawada, A.; Faniel, S.; Mineshige, S.; Kawabata, S.; Saito, K.; Kobayashi, K.; Sekine, Y.; Sugiyama, H.; Koga, T.

2018-05-01

We report an approach for examining electron properties using information about the shape and size of a nanostructure as a measurement reference. This approach quantifies the spin precession angles per unit length directly by considering the time-reversal interferences on chaotic return trajectories within mesoscopic ring arrays (MRAs). Experimentally, we fabricated MRAs using nanolithography in InGaAs quantum wells which had a gate-controllable spin-orbit interaction (SOI). As a result, we observed an Onsager symmetry related to relativistic magnetic fields, which provided us with indispensable information for the semiclassical billiard ball simulation. Our simulations, developed based on the real-space formalism of the weak localization/antilocalization effect including the degree of freedom for electronic spin, reproduced the experimental magnetoconductivity (MC) curves with high fidelity. The values of five distinct electron parameters (Fermi wavelength, spin precession angles per unit length for two different SOIs, impurity scattering length, and phase coherence length) were thereby extracted from a single MC curve. The methodology developed here is applicable to wide ranges of nanomaterials and devices, providing a diagnostic tool for exotic properties of two-dimensional electron systems.

Consequences of Spatial Antisymmetry on Light

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mascarenhas, Angelo; Fluegel, Brian

2016-12-21

Light propagation in two and three dimensional lattices for which the index of refraction exhibits spatial antisymmetry is investigated in the ray and photonic crystal regimes. In these regimes, all the two dimensional antisymmetry groups for which light fails to propagate are identified. In the ray-regime, it is observed that in tilings described by 7 of the 46 two dimensional antisymmetric groups, light is localized within a fundamental domain and does not propagate through the tiling, in contrast to the behavior in the other 39 groups. To understand the above phenomenon, a rule based on the number of anti-mirror planesmore » passing through a single Bravais lattice point is derived. In the wave regime for photonic crystals, it is observed that there are no propagating eigensolutions for the same 7 tilings as above, whereas propagating solutions and energy pass band dispersion curves can be obtained for the other 39 groups. The reasons underlying this peculiar behavior are analyzed using the topological approach for modeling flow in dynamical billiards to shed light on the applicability of Bloch's theorem for these periodic antisymmetric lattices.« less

Direct observation of impact propagation and absorption in dense colloidal monolayers

NASA Astrophysics Data System (ADS)

Buttinoni, Ivo; Cha, Jinwoong; Lin, Wei-Hsun; Job, Stéphane; Daraio, Chiara; Isa, Lucio

2017-11-01

Dense colloidal suspensions can propagate and absorb large mechanical stresses, including impacts and shocks. The wave transport stems from the delicate interplay between the spatial arrangement of the structural units and solvent-mediated effects. For dynamic microscopic systems, elastic deformations of the colloids are usually disregarded due to the damping imposed by the surrounding fluid. Here, we study the propagation of localized mechanical pulses in aqueous monolayers of micron-sized particles of controlled microstructure. We generate extreme localized deformation rates by exciting a target particle via pulsed-laser ablation. In crystalline monolayers, stress propagation fronts take place, where fast-moving particles (V approximately a few meters per second) are aligned along the symmetry axes of the lattice. Conversely, more viscous solvents and disordered structures lead to faster and isotropic energy absorption. Our results demonstrate the accessibility of a regime where elastic collisions also become relevant for suspensions of microscopic particles, behaving as “billiard balls” in a liquid, in analogy with regular packings of macroscopic spheres. We furthermore quantify the scattering of an impact as a function of the local structural disorder.

Direct observation of impact propagation and absorption in dense colloidal monolayers

PubMed Central

Cha, Jinwoong; Lin, Wei-Hsun; Job, Stéphane; Daraio, Chiara

2017-01-01

Dense colloidal suspensions can propagate and absorb large mechanical stresses, including impacts and shocks. The wave transport stems from the delicate interplay between the spatial arrangement of the structural units and solvent-mediated effects. For dynamic microscopic systems, elastic deformations of the colloids are usually disregarded due to the damping imposed by the surrounding fluid. Here, we study the propagation of localized mechanical pulses in aqueous monolayers of micron-sized particles of controlled microstructure. We generate extreme localized deformation rates by exciting a target particle via pulsed-laser ablation. In crystalline monolayers, stress propagation fronts take place, where fast-moving particles (V approximately a few meters per second) are aligned along the symmetry axes of the lattice. Conversely, more viscous solvents and disordered structures lead to faster and isotropic energy absorption. Our results demonstrate the accessibility of a regime where elastic collisions also become relevant for suspensions of microscopic particles, behaving as “billiard balls” in a liquid, in analogy with regular packings of macroscopic spheres. We furthermore quantify the scattering of an impact as a function of the local structural disorder. PMID:29087329

The FIFE Project at Fermilab

DOE Office of Scientific and Technical Information (OSTI.GOV)

Box, D.; Boyd, J.; Di Benedetto, V.

2016-01-01

The FabrIc for Frontier Experiments (FIFE) project is an initiative within the Fermilab Scientific Computing Division designed to steer the computing model for non-LHC Fermilab experiments across multiple physics areas. FIFE is a collaborative effort between experimenters and computing professionals to design and develop integrated computing models for experiments of varying size, needs, and infrastructure. The major focus of the FIFE project is the development, deployment, and integration of solutions for high throughput computing, data management, database access and collaboration management within an experiment. To accomplish this goal, FIFE has developed workflows that utilize Open Science Grid compute sites alongmore » with dedicated and commercial cloud resources. The FIFE project has made significant progress integrating into experiment computing operations several services including a common job submission service, software and reference data distribution through CVMFS repositories, flexible and robust data transfer clients, and access to opportunistic resources on the Open Science Grid. The progress with current experiments and plans for expansion with additional projects will be discussed. FIFE has taken the leading role in defining the computing model for Fermilab experiments, aided in the design of experiments beyond those hosted at Fermilab, and will continue to define the future direction of high throughput computing for future physics experiments worldwide.« less

Investigation of the computer experiences and attitudes of pre-service mathematics teachers: new evidence from Turkey.

PubMed

Birgin, Osman; Catlioğlu, Hakan; Gürbüz, Ramazan; Aydin, Serhat

2010-10-01

This study aimed to investigate the experiences of pre-service mathematics (PSM) teachers with computers and their attitudes toward them. The Computer Attitude Scale, Computer Competency Survey, and Computer Use Information Form were administered to 180 Turkish PSM teachers. Results revealed that most PSM teachers used computers at home and at Internet cafes, and that their competency was generally intermediate and upper level. The study concludes that PSM teachers' attitudes about computers differ according to their years of study, computer ownership, level of computer competency, frequency of computer use, computer experience, and whether they had attended a computer-aided instruction course. However, computer attitudes were not affected by gender.

Innovative Science Experiments Using Phoenix

ERIC Educational Resources Information Center

Kumar, B. P. Ajith; Satyanarayana, V. V. V.; Singh, Kundan; Singh, Parmanand

2009-01-01

A simple, flexible and very low cost hardware plus software framework for developing computer-interfaced science experiments is presented. It can be used for developing computer-interfaced science experiments without getting into the details of electronics or computer programming. For developing experiments this is a middle path between…

Application verification research of cloud computing technology in the field of real time aerospace experiment

NASA Astrophysics Data System (ADS)

Wan, Junwei; Chen, Hongyan; Zhao, Jing

2017-08-01

According to the requirements of real-time, reliability and safety for aerospace experiment, the single center cloud computing technology application verification platform is constructed. At the IAAS level, the feasibility of the cloud computing technology be applied to the field of aerospace experiment is tested and verified. Based on the analysis of the test results, a preliminary conclusion is obtained: Cloud computing platform can be applied to the aerospace experiment computing intensive business. For I/O intensive business, it is recommended to use the traditional physical machine.

Stretching the Traditional Notion of Experiment in Computing: Explorative Experiments.

PubMed

Schiaffonati, Viola

2016-06-01

Experimentation represents today a 'hot' topic in computing. If experiments made with the support of computers, such as computer simulations, have received increasing attention from philosophers of science and technology, questions such as "what does it mean to do experiments in computer science and engineering and what are their benefits?" emerged only recently as central in the debate over the disciplinary status of the discipline. In this work we aim at showing, also by means of paradigmatic examples, how the traditional notion of controlled experiment should be revised to take into account a part of the experimental practice in computing along the lines of experimentation as exploration. Taking inspiration from the discussion on exploratory experimentation in the philosophy of science-experimentation that is not theory-driven-we advance the idea of explorative experiments that, although not new, can contribute to enlarge the debate about the nature and role of experimental methods in computing. In order to further refine this concept we recast explorative experiments as socio-technical experiments, that test new technologies in their socio-technical contexts. We suggest that, when experiments are explorative, control should be intended in a posteriori form, in opposition to the a priori form that usually takes place in traditional experimental contexts.

The Fabric for Frontier Experiments Project at Fermilab

NASA Astrophysics Data System (ADS)

Kirby, Michael

2014-06-01

The FabrIc for Frontier Experiments (FIFE) project is a new, far-reaching initiative within the Fermilab Scientific Computing Division to drive the future of computing services for experiments at FNAL and elsewhere. It is a collaborative effort between computing professionals and experiment scientists to produce an end-to-end, fully integrated set of services for computing on the grid and clouds, managing data, accessing databases, and collaborating within experiments. FIFE includes 1) easy to use job submission services for processing physics tasks on the Open Science Grid and elsewhere; 2) an extensive data management system for managing local and remote caches, cataloging, querying, moving, and tracking the use of data; 3) custom and generic database applications for calibrations, beam information, and other purposes; 4) collaboration tools including an electronic log book, speakers bureau database, and experiment membership database. All of these aspects will be discussed in detail. FIFE sets the direction of computing at Fermilab experiments now and in the future, and therefore is a major driver in the design of computing services worldwide.

Evolving technologies for Space Station Freedom computer-based workstations

NASA Technical Reports Server (NTRS)

Jensen, Dean G.; Rudisill, Marianne

1990-01-01

Viewgraphs on evolving technologies for Space Station Freedom computer-based workstations are presented. The human-computer computer software environment modules are described. The following topics are addressed: command and control workstation concept; cupola workstation concept; Japanese experiment module RMS workstation concept; remote devices controlled from workstations; orbital maneuvering vehicle free flyer; remote manipulator system; Japanese experiment module exposed facility; Japanese experiment module small fine arm; flight telerobotic servicer; human-computer interaction; and workstation/robotics related activities.

Optimization of Multi-Fidelity Computer Experiments via the EQIE Criterion

DOE Office of Scientific and Technical Information (OSTI.GOV)

He, Xu; Tuo, Rui; Jeff Wu, C. F.

Computer experiments based on mathematical models are powerful tools for understanding physical processes. This article addresses the problem of kriging-based optimization for deterministic computer experiments with tunable accuracy. Our approach is to use multi- delity computer experiments with increasing accuracy levels and a nonstationary Gaussian process model. We propose an optimization scheme that sequentially adds new computer runs by following two criteria. The first criterion, called EQI, scores candidate inputs with given level of accuracy, and the second criterion, called EQIE, scores candidate combinations of inputs and accuracy. Here, from simulation results and a real example using finite element analysis,more » our method out-performs the expected improvement (EI) criterion which works for single-accuracy experiments.« less

Optimization of Multi-Fidelity Computer Experiments via the EQIE Criterion

DOE PAGES

He, Xu; Tuo, Rui; Jeff Wu, C. F.

2017-01-31

Computer experiments based on mathematical models are powerful tools for understanding physical processes. This article addresses the problem of kriging-based optimization for deterministic computer experiments with tunable accuracy. Our approach is to use multi- delity computer experiments with increasing accuracy levels and a nonstationary Gaussian process model. We propose an optimization scheme that sequentially adds new computer runs by following two criteria. The first criterion, called EQI, scores candidate inputs with given level of accuracy, and the second criterion, called EQIE, scores candidate combinations of inputs and accuracy. Here, from simulation results and a real example using finite element analysis,more » our method out-performs the expected improvement (EI) criterion which works for single-accuracy experiments.« less

Response Surface Model Building Using Orthogonal Arrays for Computer Experiments

NASA Technical Reports Server (NTRS)

Unal, Resit; Braun, Robert D.; Moore, Arlene A.; Lepsch, Roger A.

1997-01-01

This study investigates response surface methods for computer experiments and discusses some of the approaches available. Orthogonal arrays constructed for computer experiments are studied and an example application to a technology selection and optimization study for a reusable launch vehicle is presented.

Using the Computer as a Laboratory Instrument.

ERIC Educational Resources Information Center

Collings, Peter J.; Greenslade, Thomas B., Jr.

1989-01-01

Reports experiences during a two-year period in introducing the computer to the laboratory and students to the computer as a laboratory instrument. Describes a working philosophy, data acquisition system, and experiments. Summarizes the laboratory procedures of nine experiments, covering mechanics, heat, electromagnetism, and optics. (YP)

The Fabric for Frontier Experiments Project at Fermilab

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kirby, Michael

2014-01-01

The FabrIc for Frontier Experiments (FIFE) project is a new, far-reaching initiative within the Fermilab Scientific Computing Division to drive the future of computing services for experiments at FNAL and elsewhere. It is a collaborative effort between computing professionals and experiment scientists to produce an end-to-end, fully integrated set of services for computing on the grid and clouds, managing data, accessing databases, and collaborating within experiments. FIFE includes 1) easy to use job submission services for processing physics tasks on the Open Science Grid and elsewhere, 2) an extensive data management system for managing local and remote caches, cataloging, querying,more » moving, and tracking the use of data, 3) custom and generic database applications for calibrations, beam information, and other purposes, 4) collaboration tools including an electronic log book, speakers bureau database, and experiment membership database. All of these aspects will be discussed in detail. FIFE sets the direction of computing at Fermilab experiments now and in the future, and therefore is a major driver in the design of computing services worldwide.« less

The Information Science Experiment System - The computer for science experiments in space

NASA Technical Reports Server (NTRS)

Foudriat, Edwin C.; Husson, Charles

1989-01-01

The concept of the Information Science Experiment System (ISES), potential experiments, and system requirements are reviewed. The ISES is conceived as a computer resource in space whose aim is to assist computer, earth, and space science experiments, to develop and demonstrate new information processing concepts, and to provide an experiment base for developing new information technology for use in space systems. The discussion covers system hardware and architecture, operating system software, the user interface, and the ground communication link.

Development of Computer-Based Experiment Set on Simple Harmonic Motion of Mass on Springs

ERIC Educational Resources Information Center

Musik, Panjit

2017-01-01

The development of computer-based experiment set has become necessary in teaching physics in schools so that students can learn from their real experiences. The purpose of this study is to create and to develop the computer-based experiment set on simple harmonic motion of mass on springs for teaching and learning physics. The average period of…

Quantum transport in chaotic and integrable ballistic cavities with tunable shape

NASA Astrophysics Data System (ADS)

Lee, Y.; Faini, G.; Mailly, D.

1997-10-01

We have performed magnetotransport measurements in ballistic cavities and obtained the average by small modulations on the shapes and/or on the Fermi level. We work with cavities whose underlying classical dynamics is chaotic (stadia and Sinaï billiards) and integrable (circles and rectangles). The former show a Lorentzian weak-localization peak, in agreement with semiclassical predictions and other averaging methods that have been used in recent measurements. For integrable cavities our measurements show that the shape of the weak localization is very sensitive to the exact geometry of the sample: a linear magnetoconductance has been observed for rectangles as expected by the theory for integrable cavities, whereas for circles the shape is always Lorentzian. These discrepancies illustrate the nongeneric behavior of scattering through integrable geometries, that we analyze taking into account the interplay of integrability with smooth disorder and geometrical effects. The power spectra of the conductance fluctuations are also analyzed, the deduced typical areas are in good agreement with those obtained from the weak localization. Periodic orbits in nonaveraged Fourier transforms of the magnetoconductance for regular cavities are clearly identified indicating the good quality of our samples.

Democratizing Children's Computation: Learning Computational Science as Aesthetic Experience

ERIC Educational Resources Information Center

Farris, Amy Voss; Sengupta, Pratim

2016-01-01

In this essay, Amy Voss Farris and Pratim Sengupta argue that a democratic approach to children's computing education in a science class must focus on the "aesthetics" of children's experience. In "Democracy and Education," Dewey links "democracy" with a distinctive understanding of "experience." For Dewey,…

Measurement of information and communication technology experience and attitudes to e-learning of students in the healthcare professions: integrative review.

PubMed

Wilkinson, Ann; While, Alison E; Roberts, Julia

2009-04-01

This paper is a report of a review to describe and discuss the psychometric properties of instruments used in healthcare education settings measuring experience and attitudes of healthcare students regarding their information and communication technology skills and their use of computers and the Internet for education. Healthcare professionals are expected to be computer and information literate at registration. A previous review of evaluative studies of computer-based learning suggests that methods of measuring learners' attitudes to computers and computer aided learning are problematic. A search of eight health and social science databases located 49 papers, the majority published between 1995 and January 2007, focusing on the experience and attitudes of students in the healthcare professions towards computers and e-learning. An integrative approach was adopted, with narrative description of findings. Criteria for inclusion were quantitative studies using survey tools with samples of healthcare students and concerning computer and information literacy skills, access to computers, experience with computers and use of computers and the Internet for education purposes. Since the 1980s a number of instruments have been developed, mostly in the United States of America, to measure attitudes to computers, anxiety about computer use, information and communication technology skills, satisfaction and more recently attitudes to the Internet and computers for education. The psychometric properties are poorly described. Advances in computers and technology mean that many earlier tools are no longer valid. Measures of the experience and attitudes of healthcare students to the increased use of e-learning require development in line with computer and technology advances.

Enhancing the Undergraduate Computing Experience in Chemical Engineering CACHE Corporation

ERIC Educational Resources Information Center

Edgar, Thomas F.

2006-01-01

This white paper focuses on the integration and enhancement of the computing experience for undergraduates throughout the chemical engineering curriculum. The computing experience for undergraduates in chemical engineering should have continuity and be coordinated from course to course, because a single software solution is difficult to achieve in…

Influence of direct computer experience on older adults' attitudes toward computers.

PubMed

Jay, G M; Willis, S L

1992-07-01

This research examined whether older adults' attitudes toward computers became more positive as a function of computer experience. The sample comprised 101 community-dwelling older adults aged 57 to 87. The intervention involved a 2-week computer training program in which subjects learned to use a desktop publishing software program. A multidimensional computer attitude measure was used to assess differential attitude change and maintenance of change following training. The results indicated that older adults' computer attitudes are modifiable and that direct computer experience is an effective means of change. Attitude change as a function of training was found for the attitude dimensions targeted by the intervention program: computer comfort and efficacy. In addition, maintenance of attitude change was established for at least two weeks following training.

AnnotCompute: annotation-based exploration and meta-analysis of genomics experiments

PubMed Central

Zheng, Jie; Stoyanovich, Julia; Manduchi, Elisabetta; Liu, Junmin; Stoeckert, Christian J.

2011-01-01

The ever-increasing scale of biological data sets, particularly those arising in the context of high-throughput technologies, requires the development of rich data exploration tools. In this article, we present AnnotCompute, an information discovery platform for repositories of functional genomics experiments such as ArrayExpress. Our system leverages semantic annotations of functional genomics experiments with controlled vocabulary and ontology terms, such as those from the MGED Ontology, to compute conceptual dissimilarities between pairs of experiments. These dissimilarities are then used to support two types of exploratory analysis—clustering and query-by-example. We show that our proposed dissimilarity measures correspond to a user's intuition about conceptual dissimilarity, and can be used to support effective query-by-example. We also evaluate the quality of clustering based on these measures. While AnnotCompute can support a richer data exploration experience, its effectiveness is limited in some cases, due to the quality of available annotations. Nonetheless, tools such as AnnotCompute may provide an incentive for richer annotations of experiments. Code is available for download at http://www.cbil.upenn.edu/downloads/AnnotCompute. Database URL: http://www.cbil.upenn.edu/annotCompute/ PMID:22190598

Comfort and experience with online learning: trends over nine years and associations with knowledge.

PubMed

Cook, David A; Thompson, Warren G

2014-07-01

Some evidence suggests that attitude toward computer-based instruction is an important determinant of success in online learning. We sought to determine how comfort using computers and perceptions of prior online learning experiences have changed over the past decade, and how these associate with learning outcomes. Each year from 2003-2011 we conducted a prospective trial of online learning. As part of each year's study, we asked medicine residents about their comfort using computers and if their previous experiences with online learning were favorable. We assessed knowledge using a multiple-choice test. We used regression to analyze associations and changes over time. 371 internal medicine and family medicine residents participated. Neither comfort with computers nor perceptions of prior online learning experiences showed a significant change across years (p > 0.61), with mean comfort rating 3.96 (maximum 5 = very comfortable) and mean experience rating 4.42 (maximum 6 = strongly agree [favorable]). Comfort showed no significant association with knowledge scores (p = 0.39) but perceptions of prior experiences did, with a 1.56% rise in knowledge score for a 1-point rise in experience score (p = 0.02). Correlations among comfort, perceptions of prior experiences, and number of prior experiences were all small and not statistically significant. Comfort with computers and perceptions of prior experience with online learning remained stable over nine years. Prior good experiences (but not comfort with computers) demonstrated a modest association with knowledge outcomes, suggesting that prior course satisfaction may influence subsequent learning.

One Head Start Classroom's Experience: Computers and Young Children's Development.

ERIC Educational Resources Information Center

Fischer, Melissa Anne; Gillespie, Catherine Wilson

2003-01-01

Contends that early childhood educators need to understand how exposure to computers and constructive computer programs affects the development of children. Specifically examines: (1) research on children's technology experiences; (2) determining best practices; and (3) addressing educators' concerns about computers replacing other developmentally…

Interdisciplinary Team-Teaching Experience for a Computer and Nuclear Energy Course for Electrical and Computer Engineering Students

ERIC Educational Resources Information Center

Kim, Charles; Jackson, Deborah; Keiller, Peter

2016-01-01

A new, interdisciplinary, team-taught course has been designed to educate students in Electrical and Computer Engineering (ECE) so that they can respond to global and urgent issues concerning computer control systems in nuclear power plants. This paper discusses our experience and assessment of the interdisciplinary computer and nuclear energy…

Computation of Chemical Shifts for Paramagnetic Molecules: A Laboratory Experiment for the Undergraduate Curriculum

ERIC Educational Resources Information Center

Pritchard, Benjamin P.; Simpson, Scott; Zurek, Eva; Autschbach, Jochen

2014-01-01

A computational experiment investigating the [superscript 1]H and [superscript 13]C nuclear magnetic resonance (NMR) chemical shifts of molecules with unpaired electrons has been developed and implemented. This experiment is appropriate for an upper-level undergraduate laboratory course in computational, physical, or inorganic chemistry. The…

Using Computer Games for Instruction: The Student Experience

ERIC Educational Resources Information Center

Grimley, Michael; Green, Richard; Nilsen, Trond; Thompson, David; Tomes, Russell

2011-01-01

Computer games are fun, exciting and motivational when used as leisure pursuits. But do they have similar attributes when utilized for educational purposes? This article investigates whether learning by computer game can improve student experiences compared with a more formal lecture approach and whether computer games have potential for improving…

Experience with a UNIX based batch computing facility for H1

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gerhards, R.; Kruener-Marquis, U.; Szkutnik, Z.

1994-12-31

A UNIX based batch computing facility for the H1 experiment at DESY is described. The ultimate goal is to replace the DESY IBM mainframe by a multiprocessor SGI Challenge series computer, using the UNIX operating system, for most of the computing tasks in H1.

Predictors of Computer Anxiety and Performance in Information Systems.

ERIC Educational Resources Information Center

Anderson, Alastair A.

1996-01-01

Reports on the results of a study of business undergraduates in Australia that was conducted to determine whether or not perceived knowledge of software, microcomputer experience, overall knowledge of computers, programming experience, and gender were predictors of computer anxiety. Use of the Computer Anxiety Rating Scale is discussed.…

Emergent Leadership and Team Effectiveness on a Team Resource Allocation Task

DTIC Science & Technology

1987-10-01

equivalent training and experience on this task, but they had different levels of experience with computers and video games . This differential experience...typed: that is. it is sex-typed to the extent that males spend mnore time on related instrumeuts like computers and video games . However. the sex...perform better or worse than less talkative teams? Did teams with much computer and ’or video game experience perform better than inexperienced teams

Comparing Computer Game and Traditional Lecture Using Experience Ratings from High and Low Achieving Students

ERIC Educational Resources Information Center

Grimley, Michael; Green, Richard; Nilsen, Trond; Thompson, David

2012-01-01

Computer games are purported to be effective instructional tools that enhance motivation and improve engagement. The aim of this study was to investigate how tertiary student experiences change when instruction was computer game based compared to lecture based, and whether experiences differed between high and low achieving students. Participants…

Integrated design, execution, and analysis of arrayed and pooled CRISPR genome-editing experiments.

PubMed

Canver, Matthew C; Haeussler, Maximilian; Bauer, Daniel E; Orkin, Stuart H; Sanjana, Neville E; Shalem, Ophir; Yuan, Guo-Cheng; Zhang, Feng; Concordet, Jean-Paul; Pinello, Luca

2018-05-01

CRISPR (clustered regularly interspaced short palindromic repeats) genome-editing experiments offer enormous potential for the evaluation of genomic loci using arrayed single guide RNAs (sgRNAs) or pooled sgRNA libraries. Numerous computational tools are available to help design sgRNAs with optimal on-target efficiency and minimal off-target potential. In addition, computational tools have been developed to analyze deep-sequencing data resulting from genome-editing experiments. However, these tools are typically developed in isolation and oftentimes are not readily translatable into laboratory-based experiments. Here, we present a protocol that describes in detail both the computational and benchtop implementation of an arrayed and/or pooled CRISPR genome-editing experiment. This protocol provides instructions for sgRNA design with CRISPOR (computational tool for the design, evaluation, and cloning of sgRNA sequences), experimental implementation, and analysis of the resulting high-throughput sequencing data with CRISPResso (computational tool for analysis of genome-editing outcomes from deep-sequencing data). This protocol allows for design and execution of arrayed and pooled CRISPR experiments in 4-5 weeks by non-experts, as well as computational data analysis that can be performed in 1-2 d by both computational and noncomputational biologists alike using web-based and/or command-line versions.

Comfort and experience with online learning: trends over nine years and associations with knowledge

PubMed Central

2014-01-01

Background Some evidence suggests that attitude toward computer-based instruction is an important determinant of success in online learning. We sought to determine how comfort using computers and perceptions of prior online learning experiences have changed over the past decade, and how these associate with learning outcomes. Methods Each year from 2003–2011 we conducted a prospective trial of online learning. As part of each year’s study, we asked medicine residents about their comfort using computers and if their previous experiences with online learning were favorable. We assessed knowledge using a multiple-choice test. We used regression to analyze associations and changes over time. Results 371 internal medicine and family medicine residents participated. Neither comfort with computers nor perceptions of prior online learning experiences showed a significant change across years (p > 0.61), with mean comfort rating 3.96 (maximum 5 = very comfortable) and mean experience rating 4.42 (maximum 6 = strongly agree [favorable]). Comfort showed no significant association with knowledge scores (p = 0.39) but perceptions of prior experiences did, with a 1.56% rise in knowledge score for a 1-point rise in experience score (p = 0.02). Correlations among comfort, perceptions of prior experiences, and number of prior experiences were all small and not statistically significant. Conclusions Comfort with computers and perceptions of prior experience with online learning remained stable over nine years. Prior good experiences (but not comfort with computers) demonstrated a modest association with knowledge outcomes, suggesting that prior course satisfaction may influence subsequent learning. PMID:24985690

A meta-analysis of outcomes from the use of computer-simulated experiments in science education

NASA Astrophysics Data System (ADS)

Lejeune, John Van

The purpose of this study was to synthesize the findings from existing research on the effects of computer simulated experiments on students in science education. Results from 40 reports were integrated by the process of meta-analysis to examine the effect of computer-simulated experiments and interactive videodisc simulations on student achievement and attitudes. Findings indicated significant positive differences in both low-level and high-level achievement of students who use computer-simulated experiments and interactive videodisc simulations as compared to students who used more traditional learning activities. No significant differences in retention, student attitudes toward the subject, or toward the educational method were found. Based on the findings of this study, computer-simulated experiments and interactive videodisc simulations should be used to enhance students' learning in science, especially in cases where the use of traditional laboratory activities are expensive, dangerous, or impractical.

Educational Computer Use in Leisure Contexts: A Phenomenological Study of Adolescents' Experiences at Internet Cafes

ERIC Educational Resources Information Center

Cilesiz, Sebnem

2009-01-01

Computer use is a widespread leisure activity for adolescents. Leisure contexts, such as Internet cafes, constitute specific social environments for computer use and may hold significant educational potential. This article reports a phenomenological study of adolescents' experiences of educational computer use at Internet cafes in Turkey. The…

Computers in Science Education: Can They Go Far Enough? Have We Gone Too Far?

ERIC Educational Resources Information Center

Schrock, John Richard

1984-01-01

Indicates that although computers may churn out creative research, science is still dependent on science education, and that science education consists of increasing human experience. Also considers uses and misuses of computers in the science classroom, examining Edgar Dale's "cone of experience" related to laboratory computer and "extended…

AEC Experiment Establishes Computer Link Between California and Paris

Science.gov Websites

demonstrated that a terminal in Paris could search a computer in California and display the resulting (Copies) AEC EXPERIMENT ESTABLISHES COMPUTER LINK BETWEEN CALIFORNIA AND PARIS The feasibility of a worldwide information retrieval system which would tie a computer base of information to terminals on the

Ontological and Epistemological Issues Regarding Climate Models and Computer Experiments

NASA Astrophysics Data System (ADS)

Vezer, M. A.

2010-12-01

Recent philosophical discussions (Parker 2009; Frigg and Reiss 2009; Winsberg, 2009; Morgon 2002, 2003, 2005; Gula 2002) about the ontology of computer simulation experiments and the epistemology of inferences drawn from them are of particular relevance to climate science as computer modeling and analysis are instrumental in understanding climatic systems. How do computer simulation experiments compare with traditional experiments? Is there an ontological difference between these two methods of inquiry? Are there epistemological considerations that result in one type of inference being more reliable than the other? What are the implications of these questions with respect to climate studies that rely on computer simulation analysis? In this paper, I examine these philosophical questions within the context of climate science, instantiating concerns in the philosophical literature with examples found in analysis of global climate change. I concentrate on Wendy Parker’s (2009) account of computer simulation studies, which offers a treatment of these and other questions relevant to investigations of climate change involving such modelling. Two theses at the center of Parker’s account will be the focus of this paper. The first is that computer simulation experiments ought to be regarded as straightforward material experiments; which is to say, there is no significant ontological difference between computer and traditional experimentation. Parker’s second thesis is that some of the emphasis on the epistemological importance of materiality has been misplaced. I examine both of these claims. First, I inquire as to whether viewing computer and traditional experiments as ontologically similar in the way she does implies that there is no proper distinction between abstract experiments (such as ‘thought experiments’ as well as computer experiments) and traditional ‘concrete’ ones. Second, I examine the notion of materiality (i.e., the material commonality between object and target systems) and some arguments for the claim that materiality entails some inferential advantage to traditional experimentation. I maintain that Parker’s account of the ontology of computer simulations has some interesting though potentially problematic implications regarding conventional distinctions between abstract and concrete methods of inquiry. With respect to her account of materiality, I outline and defend an alternative account, posited by Mary Morgan (2002, 2003, 2005), which holds that ontological similarity between target and object systems confers some epistemological advantage to traditional forms of experimental inquiry.

Fermilab computing at the Intensity Frontier

DOE PAGES

Group, Craig; Fuess, S.; Gutsche, O.; ...

2015-12-23

The Intensity Frontier refers to a diverse set of particle physics experiments using high- intensity beams. In this paper I will focus the discussion on the computing requirements and solutions of a set of neutrino and muon experiments in progress or planned to take place at the Fermi National Accelerator Laboratory located near Chicago, Illinois. In addition, the experiments face unique challenges, but also have overlapping computational needs. In principle, by exploiting the commonality and utilizing centralized computing tools and resources, requirements can be satisfied efficiently and scientists of individual experiments can focus more on the science and less onmore » the development of tools and infrastructure.« less

Computer use changes generalization of movement learning.

PubMed

Wei, Kunlin; Yan, Xiang; Kong, Gaiqing; Yin, Cong; Zhang, Fan; Wang, Qining; Kording, Konrad Paul

2014-01-06

Over the past few decades, one of the most salient lifestyle changes for us has been the use of computers. For many of us, manual interaction with a computer occupies a large portion of our working time. Through neural plasticity, this extensive movement training should change our representation of movements (e.g., [1-3]), just like search engines affect memory [4]. However, how computer use affects motor learning is largely understudied. Additionally, as virtually all participants in studies of perception and actions are computer users, a legitimate question is whether insights from these studies bear the signature of computer-use experience. We compared non-computer users with age- and education-matched computer users in standard motor learning experiments. We found that people learned equally fast but that non-computer users generalized significantly less across space, a difference negated by two weeks of intensive computer training. Our findings suggest that computer-use experience shaped our basic sensorimotor behaviors, and this influence should be considered whenever computer users are recruited as study participants. Copyright © 2014 Elsevier Ltd. All rights reserved.

Belle II grid computing: An overview of the distributed data management system.

NASA Astrophysics Data System (ADS)

Bansal, Vikas; Schram, Malachi; Belle Collaboration, II

2017-01-01

The Belle II experiment at the SuperKEKB collider in Tsukuba, Japan, will start physics data taking in 2018 and will accumulate 50/ab of e +e- collision data, about 50 times larger than the data set of the Belle experiment. The computing requirements of Belle II are comparable to those of a Run I LHC experiment. Computing at this scale requires efficient use of the compute grids in North America, Asia and Europe and will take advantage of upgrades to the high-speed global network. We present the architecture of data flow and data handling as a part of the Belle II computing infrastructure.

MOLNs: A CLOUD PLATFORM FOR INTERACTIVE, REPRODUCIBLE, AND SCALABLE SPATIAL STOCHASTIC COMPUTATIONAL EXPERIMENTS IN SYSTEMS BIOLOGY USING PyURDME.

PubMed

Drawert, Brian; Trogdon, Michael; Toor, Salman; Petzold, Linda; Hellander, Andreas

2016-01-01

Computational experiments using spatial stochastic simulations have led to important new biological insights, but they require specialized tools and a complex software stack, as well as large and scalable compute and data analysis resources due to the large computational cost associated with Monte Carlo computational workflows. The complexity of setting up and managing a large-scale distributed computation environment to support productive and reproducible modeling can be prohibitive for practitioners in systems biology. This results in a barrier to the adoption of spatial stochastic simulation tools, effectively limiting the type of biological questions addressed by quantitative modeling. In this paper, we present PyURDME, a new, user-friendly spatial modeling and simulation package, and MOLNs, a cloud computing appliance for distributed simulation of stochastic reaction-diffusion models. MOLNs is based on IPython and provides an interactive programming platform for development of sharable and reproducible distributed parallel computational experiments.

Senior Surfing: Computer Use, Aging, and Formal Training

ERIC Educational Resources Information Center

Warren-Peace, Paula; Parrish, Elaine; Peace, C. Brian; Xu, Jianzhong

2008-01-01

In this article, we describe data from two case studies of seniors (one younger senior and one older senior) in learning to use computers. The study combined interviews, observations, and documents to take a close look at their experiences with computers, as well as the influences of aging and computer training on their experiences. The study…

Fluid/Structure Interaction Studies of Aircraft Using High Fidelity Equations on Parallel Computers

NASA Technical Reports Server (NTRS)

Guruswamy, Guru; VanDalsem, William (Technical Monitor)

1994-01-01

Abstract Aeroelasticity which involves strong coupling of fluids, structures and controls is an important element in designing an aircraft. Computational aeroelasticity using low fidelity methods such as the linear aerodynamic flow equations coupled with the modal structural equations are well advanced. Though these low fidelity approaches are computationally less intensive, they are not adequate for the analysis of modern aircraft such as High Speed Civil Transport (HSCT) and Advanced Subsonic Transport (AST) which can experience complex flow/structure interactions. HSCT can experience vortex induced aeroelastic oscillations whereas AST can experience transonic buffet associated structural oscillations. Both aircraft may experience a dip in the flutter speed at the transonic regime. For accurate aeroelastic computations at these complex fluid/structure interaction situations, high fidelity equations such as the Navier-Stokes for fluids and the finite-elements for structures are needed. Computations using these high fidelity equations require large computational resources both in memory and speed. Current conventional super computers have reached their limitations both in memory and speed. As a result, parallel computers have evolved to overcome the limitations of conventional computers. This paper will address the transition that is taking place in computational aeroelasticity from conventional computers to parallel computers. The paper will address special techniques needed to take advantage of the architecture of new parallel computers. Results will be illustrated from computations made on iPSC/860 and IBM SP2 computer by using ENSAERO code that directly couples the Euler/Navier-Stokes flow equations with high resolution finite-element structural equations.

Progress in Machine Learning Studies for the CMS Computing Infrastructure

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bonacorsi, Daniele; Kuznetsov, Valentin; Magini, Nicolo

Here, computing systems for LHC experiments developed together with Grids worldwide. While a complete description of the original Grid-based infrastructure and services for LHC experiments and its recent evolutions can be found elsewhere, it is worth to mention here the scale of the computing resources needed to fulfill the needs of LHC experiments in Run-1 and Run-2 so far.

Progress in Machine Learning Studies for the CMS Computing Infrastructure

DOE PAGES

Bonacorsi, Daniele; Kuznetsov, Valentin; Magini, Nicolo; ...

2017-12-06

Here, computing systems for LHC experiments developed together with Grids worldwide. While a complete description of the original Grid-based infrastructure and services for LHC experiments and its recent evolutions can be found elsewhere, it is worth to mention here the scale of the computing resources needed to fulfill the needs of LHC experiments in Run-1 and Run-2 so far.

Computer-Aided Experiment Planning toward Causal Discovery in Neuroscience.

PubMed

Matiasz, Nicholas J; Wood, Justin; Wang, Wei; Silva, Alcino J; Hsu, William

2017-01-01

Computers help neuroscientists to analyze experimental results by automating the application of statistics; however, computer-aided experiment planning is far less common, due to a lack of similar quantitative formalisms for systematically assessing evidence and uncertainty. While ontologies and other Semantic Web resources help neuroscientists to assimilate required domain knowledge, experiment planning requires not only ontological but also epistemological (e.g., methodological) information regarding how knowledge was obtained. Here, we outline how epistemological principles and graphical representations of causality can be used to formalize experiment planning toward causal discovery. We outline two complementary approaches to experiment planning: one that quantifies evidence per the principles of convergence and consistency, and another that quantifies uncertainty using logical representations of constraints on causal structure. These approaches operationalize experiment planning as the search for an experiment that either maximizes evidence or minimizes uncertainty. Despite work in laboratory automation, humans must still plan experiments and will likely continue to do so for some time. There is thus a great need for experiment-planning frameworks that are not only amenable to machine computation but also useful as aids in human reasoning.

Decision Making in Computer-Simulated Experiments.

ERIC Educational Resources Information Center

Suits, J. P.; Lagowski, J. J.

A set of interactive, computer-simulated experiments was designed to respond to the large range of individual differences in aptitude and reasoning ability generally exhibited by students enrolled in first-semester general chemistry. These experiments give students direct experience in the type of decision making needed in an experimental setting.…

Reactor transient control in support of PFR/TREAT TUCOP experiments

DOE Office of Scientific and Technical Information (OSTI.GOV)

Burrows, D.R.; Larsen, G.R.; Harrison, L.J.

1984-01-01

Unique energy deposition and experiment control requirements posed bythe PFR/TREAT series of transient undercooling/overpower (TUCOP) experiments resulted in equally unique TREAT reactor operations. New reactor control computer algorithms were written and used with the TREAT reactor control computer system to perform such functions as early power burst generation (based on test train flow conditions), burst generation produced by a step insertion of reactivity following a controlled power ramp, and shutdown (SCRAM) initiators based on both test train conditions and energy deposition. Specialized hardware was constructed to simulate test train inputs to the control computer system so that computer algorithms couldmore » be tested in real time without irradiating the experiment.« less

The effectiveness of using computer simulated experiments on junior high students' understanding of the volume displacement concept

NASA Astrophysics Data System (ADS)

Choi, Byung-Soon; Gennaro, Eugene

Several researchers have suggested that the computer holds much promise as a tool for science teachers for use in their classrooms (Bork, 1979, Lunetta & Hofstein, 1981). It also has been said that there needs to be more research in determining the effectiveness of computer software (Tinker, 1983).This study compared the effectiveness of microcomputer simulated experiences with that of parallel instruction involving hands-on laboratory experiences for teaching the concept of volume displacement to junior high school students. This study also assessed the differential effect on students' understanding of the volume displacement concept using sex of the students as another independent variable. In addition, it compared the degree of retention, after 45 days, of both treatment groups.It was found that computer simulated experiences were as effective as hands-on laboratory experiences, and that males, having had hands-on laboratory experiences, performed better on the posttest than females having had the hands-on laboratory experiences. There were no significant differences in performance when comparing males with females using the computer simulation in the learning of the displacement concept. This study also showed that there were no significant differences in the retention levels when the retention scores of the computer simulation groups were compared to those that had the hands-on laboratory experiences. However, an ANOVA of the retention test scores revealed that males in both treatment conditions retained knowledge of volume displacement better than females.

Development and Formative Evaluation of Computer Simulated College Chemistry Experiments.

ERIC Educational Resources Information Center

Cavin, Claudia S.; Cavin, E. D.

1978-01-01

This article describes the design, preparation, and initial evaluation of a set of computer-simulated chemistry experiments. The experiments entailed the use of an atomic emission spectroscope and a single-beam visible absorption spectrophometer. (Author/IRT)

Role of the ATLAS Grid Information System (AGIS) in Distributed Data Analysis and Simulation

NASA Astrophysics Data System (ADS)

Anisenkov, A. V.

2018-03-01

In modern high-energy physics experiments, particular attention is paid to the global integration of information and computing resources into a unified system for efficient storage and processing of experimental data. Annually, the ATLAS experiment performed at the Large Hadron Collider at the European Organization for Nuclear Research (CERN) produces tens of petabytes raw data from the recording electronics and several petabytes of data from the simulation system. For processing and storage of such super-large volumes of data, the computing model of the ATLAS experiment is based on heterogeneous geographically distributed computing environment, which includes the worldwide LHC computing grid (WLCG) infrastructure and is able to meet the requirements of the experiment for processing huge data sets and provide a high degree of their accessibility (hundreds of petabytes). The paper considers the ATLAS grid information system (AGIS) used by the ATLAS collaboration to describe the topology and resources of the computing infrastructure, to configure and connect the high-level software systems of computer centers, to describe and store all possible parameters, control, configuration, and other auxiliary information required for the effective operation of the ATLAS distributed computing applications and services. The role of the AGIS system in the development of a unified description of the computing resources provided by grid sites, supercomputer centers, and cloud computing into a consistent information model for the ATLAS experiment is outlined. This approach has allowed the collaboration to extend the computing capabilities of the WLCG project and integrate the supercomputers and cloud computing platforms into the software components of the production and distributed analysis workload management system (PanDA, ATLAS).

Deciphering the Landauer-Büttiker Transmission Function from Single Molecule Break Junction Experiments

NASA Astrophysics Data System (ADS)

Reuter, Matthew; Tschudi, Stephen

When investigating the electrical response properties of molecules, experiments often measure conductance whereas computation predicts transmission probabilities. Although the Landauer-Büttiker theory relates the two in the limit of coherent scattering through the molecule, a direct comparison between experiment and computation can still be difficult. Experimental data (specifically that from break junctions) is statistical and computational results are deterministic. Many studies compare the most probable experimental conductance with computation, but such an analysis discards almost all of the experimental statistics. In this work we develop tools to decipher the Landauer-Büttiker transmission function directly from experimental statistics and then apply them to enable a fairer comparison between experimental and computational results.

CERN Computing in Commercial Clouds

NASA Astrophysics Data System (ADS)

Cordeiro, C.; Field, L.; Garrido Bear, B.; Giordano, D.; Jones, B.; Keeble, O.; Manzi, A.; Martelli, E.; McCance, G.; Moreno-García, D.; Traylen, S.

2017-10-01

By the end of 2016 more than 10 Million core-hours of computing resources have been delivered by several commercial cloud providers to the four LHC experiments to run their production workloads, from simulation to full chain processing. In this paper we describe the experience gained at CERN in procuring and exploiting commercial cloud resources for the computing needs of the LHC experiments. The mechanisms used for provisioning, monitoring, accounting, alarming and benchmarking will be discussed, as well as the involvement of the LHC collaborations in terms of managing the workflows of the experiments within a multicloud environment.

Chaos removal in R +q R2 gravity: The mixmaster model

NASA Astrophysics Data System (ADS)

Moriconi, Riccardo; Montani, Giovanni; Capozziello, Salvatore

2014-11-01

We study the asymptotic dynamics of the mixmaster universe, near the cosmological singularity, considering f (R ) gravity up to a quadratic correction in the Ricci scalar R . The analysis is performed in the scalar-tensor framework and adopting Misner-Chitré-like variables to describe the mixmaster universe, whose dynamics resembles asymptotically a billiard ball in a given domain of the half-Poincaré space. The form of the potential well depends on the spatial curvature of the model and on the particular form of the self-interacting scalar field potential. We demonstrate that the potential walls determine an open domain in the configuration region, allowing the point universe to reach the absolute of the considered Lobachevsky space. In other words, we outline the existence of a stable final Kasner regime in the mixmaster evolution, implying chaos removal near the cosmological singularity. The relevance of the present issue relies both on the general nature of the considered dynamics, allowing its direct extension to the Belinski-Khalatnikov-Lifshitz conjecture too, as well as the possibility to regard the considered modified theory of gravity as the first correction to the Einstein-Hilbert action as a Taylor expansion of a generic function f (R ) (as soon as a cutoff on the space-time curvature takes place).

DIRAC in Large Particle Physics Experiments

NASA Astrophysics Data System (ADS)

Stagni, F.; Tsaregorodtsev, A.; Arrabito, L.; Sailer, A.; Hara, T.; Zhang, X.; Consortium, DIRAC

2017-10-01

The DIRAC project is developing interware to build and operate distributed computing systems. It provides a development framework and a rich set of services for both Workload and Data Management tasks of large scientific communities. A number of High Energy Physics and Astrophysics collaborations have adopted DIRAC as the base for their computing models. DIRAC was initially developed for the LHCb experiment at LHC, CERN. Later, the Belle II, BES III and CTA experiments as well as the linear collider detector collaborations started using DIRAC for their computing systems. Some of the experiments built their DIRAC-based systems from scratch, others migrated from previous solutions, ad-hoc or based on different middlewares. Adaptation of DIRAC for a particular experiment was enabled through the creation of extensions to meet their specific requirements. Each experiment has a heterogeneous set of computing and storage resources at their disposal that were aggregated through DIRAC into a coherent pool. Users from different experiments can interact with the system in different ways depending on their specific tasks, expertise level and previous experience using command line tools, python APIs or Web Portals. In this contribution we will summarize the experience of using DIRAC in particle physics collaborations. The problems of migration to DIRAC from previous systems and their solutions will be presented. An overview of specific DIRAC extensions will be given. We hope that this review will be useful for experiments considering an update, or for those designing their computing models.

Coordinate Systems, Numerical Objects and Algorithmic Operations of Computational Experiment in Fluid Mechanics

NASA Astrophysics Data System (ADS)

Degtyarev, Alexander; Khramushin, Vasily

2016-02-01

The paper deals with the computer implementation of direct computational experiments in fluid mechanics, constructed on the basis of the approach developed by the authors. The proposed approach allows the use of explicit numerical scheme, which is an important condition for increasing the effciency of the algorithms developed by numerical procedures with natural parallelism. The paper examines the main objects and operations that let you manage computational experiments and monitor the status of the computation process. Special attention is given to a) realization of tensor representations of numerical schemes for direct simulation; b) realization of representation of large particles of a continuous medium motion in two coordinate systems (global and mobile); c) computing operations in the projections of coordinate systems, direct and inverse transformation in these systems. Particular attention is paid to the use of hardware and software of modern computer systems.

A Computational Experiment on Single-Walled Carbon Nanotubes

ERIC Educational Resources Information Center

Simpson, Scott; Lonie, David C.; Chen, Jiechen; Zurek, Eva

2013-01-01

A computational experiment that investigates single-walled carbon nanotubes (SWNTs) has been developed and employed in an upper-level undergraduate physical chemistry laboratory course. Computations were carried out to determine the electronic structure, radial breathing modes, and the influence of the nanotube's diameter on the…

Computer-Based vs Paper-Based Examinations: Perceptions of University Teachers

ERIC Educational Resources Information Center

Jamil, Mubashrah; Tariq, R. H.; Shami, P. A.

2012-01-01

This research reported teachers' perceptions about computer-based (CB) vs. paper-based (PB) examinations. Teachers were divided into 7 major categories i.e., gender, departments, designations, qualifications, teaching experiences, computer training certifications and CB examination experiences, which were the key factors to be observed and…

An experiment for determining the Euler load by direct computation

NASA Technical Reports Server (NTRS)

Thurston, Gaylen A.; Stein, Peter A.

1986-01-01

A direct algorithm is presented for computing the Euler load of a column from experimental data. The method is based on exact inextensional theory for imperfect columns, which predicts two distinct deflected shapes at loads near the Euler load. The bending stiffness of the column appears in the expression for the Euler load along with the column length, therefore the experimental data allows a direct computation of bending stiffness. Experiments on graphite-epoxy columns of rectangular cross-section are reported in the paper. The bending stiffness of each composite column computed from experiment is compared with predictions from laminated plate theory.

Assessing Pre-Service Teachers' Computer Phobia Levels in Terms of Gender and Experience, Turkish Sample

ERIC Educational Resources Information Center

Ursavas, Omer Faruk; Karal, Hasan

2009-01-01

In this study it is aimed to determine the level of pre-service teachers' computer phobia. Whether or not computer phobia meaningfully varies statistically according to gender and computer experience has been tested in the study. The study was performed on 430 pre-service teachers at the Education Faculty in Rize/Turkey. Data in the study were…

Pharmacology Experiments on the Computer.

ERIC Educational Resources Information Center

Keller, Daniel

1990-01-01

A computer program that replaces a set of pharmacology and physiology laboratory experiments on live animals or isolated organs is described and illustrated. Five experiments are simulated: dose-effect relationships on smooth muscle, blood pressure and catecholamines, neuromuscular signal transmission, acetylcholine and the circulation, and…

75 FR 15675 - Professional Research Experience Program in Chemical Science and Technology Laboratory...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-03-30

... in physics, chemistry, mathematics, computer science, or engineering. Institutions should have a 4..., mathematics, computer science, or engineering with work experiences in laboratories or other settings...-0141-01] Professional Research Experience Program in Chemical Science and Technology Laboratory...

MOLNs: A CLOUD PLATFORM FOR INTERACTIVE, REPRODUCIBLE, AND SCALABLE SPATIAL STOCHASTIC COMPUTATIONAL EXPERIMENTS IN SYSTEMS BIOLOGY USING PyURDME

PubMed Central

Drawert, Brian; Trogdon, Michael; Toor, Salman; Petzold, Linda; Hellander, Andreas

2017-01-01

Computational experiments using spatial stochastic simulations have led to important new biological insights, but they require specialized tools and a complex software stack, as well as large and scalable compute and data analysis resources due to the large computational cost associated with Monte Carlo computational workflows. The complexity of setting up and managing a large-scale distributed computation environment to support productive and reproducible modeling can be prohibitive for practitioners in systems biology. This results in a barrier to the adoption of spatial stochastic simulation tools, effectively limiting the type of biological questions addressed by quantitative modeling. In this paper, we present PyURDME, a new, user-friendly spatial modeling and simulation package, and MOLNs, a cloud computing appliance for distributed simulation of stochastic reaction-diffusion models. MOLNs is based on IPython and provides an interactive programming platform for development of sharable and reproducible distributed parallel computational experiments. PMID:28190948

Computer Series, 88.

ERIC Educational Resources Information Center

Moore, John W., Ed.

1987-01-01

Describes two experiments in college chemistry which use microcomputers. One experiment deals with chemical oscillations, while the other involves colorimeter titration with laser excitation and computer-interfaced endpoint detection. (TW)

More Ideas for Monitoring Biological Experiments with the BBC Computer: Absorption Spectra, Yeast Growth, Enzyme Reactions and Animal Behaviour.

ERIC Educational Resources Information Center

Openshaw, Peter

1988-01-01

Presented are five ideas for A-level biology experiments using a laboratory computer interface. Topics investigated include photosynthesis, yeast growth, animal movements, pulse rates, and oxygen consumption and production by organisms. Includes instructions specific to the BBC computer system. (CW)

Computer-Adaptive Testing: Implications for Students' Achievement, Motivation, Engagement, and Subjective Test Experience

ERIC Educational Resources Information Center

Martin, Andrew J.; Lazendic, Goran

2018-01-01

The present study investigated the implications of computer-adaptive testing (operationalized by way of multistage adaptive testing; MAT) and "conventional" fixed order computer testing for various test-relevant outcomes in numeracy, including achievement, test-relevant motivation and engagement, and subjective test experience. It did so…

Optimization of an interactive distributive computer network

NASA Technical Reports Server (NTRS)

Frederick, V.

1985-01-01

The activities under a cooperative agreement for the development of a computer network are briefly summarized. Research activities covered are: computer operating systems optimization and integration; software development and implementation of the IRIS (Infrared Imaging of Shuttle) Experiment; and software design, development, and implementation of the APS (Aerosol Particle System) Experiment.

How Do Students Experience Testing on the University Computer?

ERIC Educational Resources Information Center

Whittington, Dale; And Others

1995-01-01

Reports a study of the administration mode, scores, and testing experiences of students taking the PreProfessional Skills Test (PPST) under differing conditions (computer based and paper and pencil). PPST scores and surveys of the students revealed varied test-taking strategies and computer-related alterations in test difficulty, construct,…

Computer Literacy Learning Emotions of ODL Teacher-Students

ERIC Educational Resources Information Center

Esterhuizen, Hendrik D.; Blignaut, A. Seugnet; Els, Christo J.; Ellis, Suria M.

2012-01-01

This paper addresses the affective human experiences in terms of the emotions of South African teacher-students while attaining computer competencies for teaching and learning, and for ODL. The full mixed method study investigated how computers contribute towards affective experiences of disadvantaged teacher-students. The purposive sample related…

Mental Rotation Ability and Computer Game Experience

ERIC Educational Resources Information Center

Gecu, Zeynep; Cagiltay, Kursat

2015-01-01

Computer games, which are currently very popular among students, can affect different cognitive abilities. The purpose of the present study is to examine undergraduate students' experiences and preferences in playing computer games as well as their mental rotation abilities. A total of 163 undergraduate students participated. The results showed a…

Line drawing of STS-34 middeck experiment Polymer Morphology (PM)

NASA Technical Reports Server (NTRS)

1989-01-01

STS-34 middeck experiment Polymer Morphology (PM) and its apparatus is illustrated in this line drawing. Apparatus for the experiment, developed by 3M, includes a Fournier transform infrared (FTIR) spectrometer, an automatic sample manipulating system and a process control and data acquisition computer known as the Generic Electronics Module (GEM). STS-34 mission specialists will interface with the PM experiment through a small, NASA-supplied laptop computer that is used as an input and output device for the main PM computer. PM experiment is an organic materials processing experiment designed to explore the effects of microgravity on polymeric materials as they are processed in space and is being conducted by 3M's Space Research and Applications Laboratory.

Consolidating WLCG topology and configuration in the Computing Resource Information Catalogue

DOE PAGES

Alandes, Maria; Andreeva, Julia; Anisenkov, Alexey; ...

2017-10-01

Here, the Worldwide LHC Computing Grid infrastructure links about 200 participating computing centres affiliated with several partner projects. It is built by integrating heterogeneous computer and storage resources in diverse data centres all over the world and provides CPU and storage capacity to the LHC experiments to perform data processing and physics analysis. In order to be used by the experiments, these distributed resources should be well described, which implies easy service discovery and detailed description of service configuration. Currently this information is scattered over multiple generic information sources like GOCDB, OIM, BDII and experiment-specific information systems. Such a modelmore » does not allow to validate topology and configuration information easily. Moreover, information in various sources is not always consistent. Finally, the evolution of computing technologies introduces new challenges. Experiments are more and more relying on opportunistic resources, which by their nature are more dynamic and should also be well described in the WLCG information system. This contribution describes the new WLCG configuration service CRIC (Computing Resource Information Catalogue) which collects information from various information providers, performs validation and provides a consistent set of UIs and APIs to the LHC VOs for service discovery and usage configuration. The main requirements for CRIC are simplicity, agility and robustness. CRIC should be able to be quickly adapted to new types of computing resources, new information sources, and allow for new data structures to be implemented easily following the evolution of the computing models and operations of the experiments.« less

Consolidating WLCG topology and configuration in the Computing Resource Information Catalogue

DOE Office of Scientific and Technical Information (OSTI.GOV)

Alandes, Maria; Andreeva, Julia; Anisenkov, Alexey

Here, the Worldwide LHC Computing Grid infrastructure links about 200 participating computing centres affiliated with several partner projects. It is built by integrating heterogeneous computer and storage resources in diverse data centres all over the world and provides CPU and storage capacity to the LHC experiments to perform data processing and physics analysis. In order to be used by the experiments, these distributed resources should be well described, which implies easy service discovery and detailed description of service configuration. Currently this information is scattered over multiple generic information sources like GOCDB, OIM, BDII and experiment-specific information systems. Such a modelmore » does not allow to validate topology and configuration information easily. Moreover, information in various sources is not always consistent. Finally, the evolution of computing technologies introduces new challenges. Experiments are more and more relying on opportunistic resources, which by their nature are more dynamic and should also be well described in the WLCG information system. This contribution describes the new WLCG configuration service CRIC (Computing Resource Information Catalogue) which collects information from various information providers, performs validation and provides a consistent set of UIs and APIs to the LHC VOs for service discovery and usage configuration. The main requirements for CRIC are simplicity, agility and robustness. CRIC should be able to be quickly adapted to new types of computing resources, new information sources, and allow for new data structures to be implemented easily following the evolution of the computing models and operations of the experiments.« less

Consolidating WLCG topology and configuration in the Computing Resource Information Catalogue

NASA Astrophysics Data System (ADS)

Alandes, Maria; Andreeva, Julia; Anisenkov, Alexey; Bagliesi, Giuseppe; Belforte, Stephano; Campana, Simone; Dimou, Maria; Flix, Jose; Forti, Alessandra; di Girolamo, A.; Karavakis, Edward; Lammel, Stephan; Litmaath, Maarten; Sciaba, Andrea; Valassi, Andrea

2017-10-01

The Worldwide LHC Computing Grid infrastructure links about 200 participating computing centres affiliated with several partner projects. It is built by integrating heterogeneous computer and storage resources in diverse data centres all over the world and provides CPU and storage capacity to the LHC experiments to perform data processing and physics analysis. In order to be used by the experiments, these distributed resources should be well described, which implies easy service discovery and detailed description of service configuration. Currently this information is scattered over multiple generic information sources like GOCDB, OIM, BDII and experiment-specific information systems. Such a model does not allow to validate topology and configuration information easily. Moreover, information in various sources is not always consistent. Finally, the evolution of computing technologies introduces new challenges. Experiments are more and more relying on opportunistic resources, which by their nature are more dynamic and should also be well described in the WLCG information system. This contribution describes the new WLCG configuration service CRIC (Computing Resource Information Catalogue) which collects information from various information providers, performs validation and provides a consistent set of UIs and APIs to the LHC VOs for service discovery and usage configuration. The main requirements for CRIC are simplicity, agility and robustness. CRIC should be able to be quickly adapted to new types of computing resources, new information sources, and allow for new data structures to be implemented easily following the evolution of the computing models and operations of the experiments.

Prevalence and correlates of problematic internet experiences and computer-using time: a two-year longitudinal study in korean school children.

PubMed

Yang, Su-Jin; Stewart, Robert; Lee, Ju-Yeon; Kim, Jae-Min; Kim, Sung-Wan; Shin, Il-Seon; Yoon, Jin-Sang

2014-01-01

To measure the prevalence of and factors associated with online inappropriate sexual exposure, cyber-bullying victimisation, and computer-using time in early adolescence. A two-year, prospective school survey was performed with 1,173 children aged 13 at baseline. Data collected included demographic factors, bullying experience, depression, anxiety, coping strategies, self-esteem, psychopathology, attention-deficit hyperactivity disorder symptoms, and school performance. These factors were investigated in relation to problematic Internet experiences and computer-using time at age 15. The prevalence of online inappropriate sexual exposure, cyber-bullying victimisation, academic-purpose computer overuse, and game-purpose computer overuse was 31.6%, 19.2%, 8.5%, and 21.8%, respectively, at age 15. Having older siblings, more weekly pocket money, depressive symptoms, anxiety symptoms, and passive coping strategy were associated with reported online sexual harassment. Male gender, depressive symptoms, and anxiety symptoms were associated with reported cyber-bullying victimisation. Female gender was associated with academic-purpose computer overuse, while male gender, lower academic level, increased height, and having older siblings were associated with game-purpose computer-overuse. Different environmental and psychological factors predicted different aspects of problematic Internet experiences and computer-using time. This knowledge is important for framing public health interventions to educate adolescents about, and prevent, internet-derived problems.

Exploiting opportunistic resources for ATLAS with ARC CE and the Event Service

NASA Astrophysics Data System (ADS)

Cameron, D.; Filipčič, A.; Guan, W.; Tsulaia, V.; Walker, R.; Wenaus, T.; ATLAS Collaboration

2017-10-01

With ever-greater computing needs and fixed budgets, big scientific experiments are turning to opportunistic resources as a means to add much-needed extra computing power. These resources can be very different in design from those that comprise the Grid computing of most experiments, therefore exploiting them requires a change in strategy for the experiment. They may be highly restrictive in what can be run or in connections to the outside world, or tolerate opportunistic usage only on condition that tasks may be terminated without warning. The Advanced Resource Connector Computing Element (ARC CE) with its nonintrusive architecture is designed to integrate resources such as High Performance Computing (HPC) systems into a computing Grid. The ATLAS experiment developed the ATLAS Event Service (AES) primarily to address the issue of jobs that can be terminated at any point when opportunistic computing capacity is needed by someone else. This paper describes the integration of these two systems in order to exploit opportunistic resources for ATLAS in a restrictive environment. In addition to the technical details, results from deployment of this solution in the SuperMUC HPC centre in Munich are shown.

Thermal/structural modeling of a large scale in situ overtest experiment for defense high level waste at the Waste Isolation Pilot Plant Facility

DOE Office of Scientific and Technical Information (OSTI.GOV)

Morgan, H.S.; Stone, C.M.; Krieg, R.D.

Several large scale in situ experiments in bedded salt formations are currently underway at the Waste Isolation Pilot Plant (WIPP) near Carlsbad, New Mexico, USA. In these experiments, the thermal and creep responses of salt around several different underground room configurations are being measured. Data from the tests are to be compared to thermal and structural responses predicted in pretest reference calculations. The purpose of these comparisons is to evaluate computational models developed from laboratory data prior to fielding of the in situ experiments. In this paper, the computational models used in the pretest reference calculation for one of themore » large scale tests, The Overtest for Defense High Level Waste, are described; and the pretest computed thermal and structural responses are compared to early data from the experiment. The comparisons indicate that computed and measured temperatures for the test agree to within ten percent but that measured deformation rates are between two and three times greater than corresponsing computed rates. 10 figs., 3 tabs.« less

The Nimrod computational workbench: a case study in desktop metacomputing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Abramson, D.; Sosic, R.; Foster, I.

The coordinated use of geographically distributed computers, or metacomputing, can in principle provide more accessible and cost- effective supercomputing than conventional high-performance systems. However, we lack evidence that metacomputing systems can be made easily usable, or that there exist large numbers of applications able to exploit metacomputing resources. In this paper, we present work that addresses both these concerns. The basis for this work is a system called Nimrod that provides a desktop problem-solving environment for parametric experiments. We describe how Nimrod has been extended to support the scheduling of computational resources located in a wide-area environment, and report onmore » an experiment in which Nimrod was used to schedule a large parametric study across the Australian Internet. The experiment provided both new scientific results and insights into Nimrod capabilities. We relate the results of this experiment to lessons learned from the I-WAY distributed computing experiment, and draw conclusions as to how Nimrod and I-WAY- like computing environments should be developed to support desktop metacomputing.« less

A Computational Model for Observation in Quantum Mechanics.

DTIC Science & Technology

1987-03-16

Interferometer experiment ............. 17 2.3 The EPR Paradox experiment ................. 22 3 The Computational Model, an Overview 28 4 Implementation 34...40 4.4 Code for the EPR paradox experiment ............... 46 4.5 Code for the double slit interferometer experiment ..... .. 50 5 Conclusions 59 A...particle run counter to fact. The EPR paradox experiment (see section 2.3) is hard to resolve with this class of models, collectively called hidden

Using Amazon's Elastic Compute Cloud to dynamically scale CMS computational resources

NASA Astrophysics Data System (ADS)

Evans, D.; Fisk, I.; Holzman, B.; Melo, A.; Metson, S.; Pordes, R.; Sheldon, P.; Tiradani, A.

2011-12-01

Large international scientific collaborations such as the Compact Muon Solenoid (CMS) experiment at the Large Hadron Collider have traditionally addressed their data reduction and analysis needs by building and maintaining dedicated computational infrastructure. Emerging cloud computing services such as Amazon's Elastic Compute Cloud (EC2) offer short-term CPU and storage resources with costs based on usage. These services allow experiments to purchase computing resources as needed, without significant prior planning and without long term investments in facilities and their management. We have demonstrated that services such as EC2 can successfully be integrated into the production-computing model of CMS, and find that they work very well as worker nodes. The cost-structure and transient nature of EC2 services makes them inappropriate for some CMS production services and functions. We also found that the resources are not truely "on-demand" as limits and caps on usage are imposed. Our trial workflows allow us to make a cost comparison between EC2 resources and dedicated CMS resources at a University, and conclude that it is most cost effective to purchase dedicated resources for the "base-line" needs of experiments such as CMS. However, if the ability to use cloud computing resources is built into an experiment's software framework before demand requires their use, cloud computing resources make sense for bursting during times when spikes in usage are required.

Accommodative and convergence response to computer screen and printed text

NASA Astrophysics Data System (ADS)

Ferreira, Andreia; Lira, Madalena; Franco, Sandra

2011-05-01

The aim of this work was to find out if differences exist in accommodative and convergence response for different computer monitors' and a printed text. It was also tried to relate the horizontal heterophoria value and accommodative response with the symptoms associated with computer use. Two independents experiments were carried out in this study. The first experiment was measuring the accommodative response on 89 subjects using the Grand Seiko WAM-5500 (Grand Seiko Co., Ltd., Japan). The accommodative response was measured using three computer monitors: a 17-inch cathode ray tube (CRT), two liquid crystal displays LCDs, one 17-inch (LCD17) and one 15 inches (LCD15) and a printed text. The text displayed was always the same for all the subjects and tests. A second experiment aimed to measure the value of habitual horizontal heterophoria on 80 subjects using the Von Graefe technique. The measurements were obtained using the same target presented on two different computer monitors, one 19-inch cathode ray tube (CRT) and other 19 inches liquid crystal displays (LCD) and printed on paper. A small survey about the incidence and prevalence of symptoms was performed similarly in both experiments. In the first experiment, the accommodation response was higher in the CRT and LCD's than for paper. There were not found significantly different response for both LCD monitors'. The second experiment showed that, the heterophoria values were similar for all the stimuli. On average, participants presented a small exophoria. In both experiments, asthenopia was the symptom that presented higher incidence. There are different accommodative responses when reading on paper or on computer monitors. This difference is more significant for CRT monitors. On the other hand, there was no difference in the values of convergence for the computer monitors' and paper. The symptoms associated with the use of computers are not related with the increase in accommodation and with the horizontal heterophoria values.

Engaging Women in Computer Science and Engineering: Promising Practices for Promoting Gender Equity in Undergraduate Research Experiences

ERIC Educational Resources Information Center

Kim, Karen A.; Fann, Amy J.; Misa-Escalante, Kimberly O.

2011-01-01

Building on research that identifies and addresses issues of women's underrepresentation in computing, this article describes promising practices in undergraduate research experiences that promote women's long-term interest in computer science and engineering. Specifically, this article explores whether and how REU programs include programmatic…

Learning Oceanography from a Computer Simulation Compared with Direct Experience at Sea

ERIC Educational Resources Information Center

Winn, William; Stahr, Frederick; Sarason, Christian; Fruland, Ruth; Oppenheimer, Peter; Lee, Yen-Ling

2006-01-01

Considerable research has compared how students learn science from computer simulations with how they learn from "traditional" classes. Little research has compared how students learn science from computer simulations with how they learn from direct experience in the real environment on which the simulations are based. This study compared two…

On-line computer system for use with low- energy nuclear physics experiments is reported

NASA Technical Reports Server (NTRS)

Gemmell, D. S.

1969-01-01

Computer program handles data from low-energy nuclear physics experiments which utilize the ND-160 pulse-height analyzer and the PHYLIS computing system. The program allows experimenters to choose from about 50 different basic data-handling functions and to prescribe the order in which these functions will be performed.

Psychology on Computers: Simulations, Experiments and Projects.

ERIC Educational Resources Information Center

Belcher, Duane M.; Smith, Stephen D.

PSYCOM is a unique mixed media package which combines high interest projects on the computer with a written text of expository material. It goes beyond most computer-assisted instruction which emphasizes drill and practice and testing of knowledge. A project might consist of a simulation or an actual experiment, or it might be a demonstration, a…

Social Construction of Computer Experience in a First-Grade Classroom: Social Processes and Mediating Artifacts.

ERIC Educational Resources Information Center

Wang, X. Christine; Ching, Cynthia Carter

2003-01-01

This ethnographic study investigated first-graders' social construction of their classroom computer experience. Findings showed that children constantly negotiate between their own individual and collective goals in the classroom as they create their own definition of computer use while conforming to the teacher's rules. Considers the usefulness…

Let Me Share a Secret with You! Teaching with Computers.

ERIC Educational Resources Information Center

de Vasconcelos, Maria

The author describes her experiences teaching a computer-enhanced Modern Poetry course. The author argues that using computers enhances the concept of the classroom as learning community. It was the author's experience that students' postings on the discussion board created an atmosphere that encouraged student involvement, as opposed to the…

A Study of Young Children's Metaknowing Talk: Learning Experiences with Computers

ERIC Educational Resources Information Center

Choi, Ji-Young

2010-01-01

This research project was undertaken in a time of increasing emphasis on the exploration of young children's learning and thinking at computers. The purpose of this study was to describe and interpret the characteristics of metaknowing talk that occurred during learning experiences with computers in a kindergarten community of learners. This…

Molecular Orbitals of NO, NO[superscript+], and NO[superscript-]: A Computational Quantum Chemistry Experiment

ERIC Educational Resources Information Center

Orenha, Renato P.; Galembeck, Sérgio E.

2014-01-01

This computational experiment presents qualitative molecular orbital (QMO) and computational quantum chemistry exercises of NO, NO[superscript+], and NO[superscript-]. Initially students explore several properties of the target molecules by Lewis diagrams and the QMO theory. Then, they compare qualitative conclusions with EHT and DFT calculations…

Advances in Grid Computing for the FabrIc for Frontier Experiments Project at Fermialb

DOE Office of Scientific and Technical Information (OSTI.GOV)

Herner, K.; Alba Hernandex, A. F.; Bhat, S.

The FabrIc for Frontier Experiments (FIFE) project is a major initiative within the Fermilab Scientic Computing Division charged with leading the computing model for Fermilab experiments. Work within the FIFE project creates close collaboration between experimenters and computing professionals to serve high-energy physics experiments of diering size, scope, and physics area. The FIFE project has worked to develop common tools for job submission, certicate management, software and reference data distribution through CVMFS repositories, robust data transfer, job monitoring, and databases for project tracking. Since the projects inception the experiments under the FIFE umbrella have signicantly matured, and present an increasinglymore » complex list of requirements to service providers. To meet these requirements, the FIFE project has been involved in transitioning the Fermilab General Purpose Grid cluster to support a partitionable slot model, expanding the resources available to experiments via the Open Science Grid, assisting with commissioning dedicated high-throughput computing resources for individual experiments, supporting the eorts of the HEP Cloud projects to provision a variety of back end resources, including public clouds and high performance computers, and developing rapid onboarding procedures for new experiments and collaborations. The larger demands also require enhanced job monitoring tools, which the project has developed using such tools as ElasticSearch and Grafana. in helping experiments manage their large-scale production work ows. This group in turn requires a structured service to facilitate smooth management of experiment requests, which FIFE provides in the form of the Production Operations Management Service (POMS). POMS is designed to track and manage requests from the FIFE experiments to run particular work ows, and support troubleshooting and triage in case of problems. Recently a new certicate management infrastructure called Distributed Computing Access with Federated Identities (DCAFI) has been put in place that has eliminated our dependence on a Fermilab-specic third-party Certicate Authority service and better accommodates FIFE collaborators without a Fermilab Kerberos account. DCAFI integrates the existing InCommon federated identity infrastructure, CILogon Basic CA, and a MyProxy service using a new general purpose open source tool. We will discuss the general FIFE onboarding strategy, progress in expanding FIFE experiments presence on the Open Science Grid, new tools for job monitoring, the POMS service, and the DCAFI project.« less

Advances in Grid Computing for the Fabric for Frontier Experiments Project at Fermilab

NASA Astrophysics Data System (ADS)

Herner, K.; Alba Hernandez, A. F.; Bhat, S.; Box, D.; Boyd, J.; Di Benedetto, V.; Ding, P.; Dykstra, D.; Fattoruso, M.; Garzoglio, G.; Kirby, M.; Kreymer, A.; Levshina, T.; Mazzacane, A.; Mengel, M.; Mhashilkar, P.; Podstavkov, V.; Retzke, K.; Sharma, N.; Teheran, J.

2017-10-01

The Fabric for Frontier Experiments (FIFE) project is a major initiative within the Fermilab Scientific Computing Division charged with leading the computing model for Fermilab experiments. Work within the FIFE project creates close collaboration between experimenters and computing professionals to serve high-energy physics experiments of differing size, scope, and physics area. The FIFE project has worked to develop common tools for job submission, certificate management, software and reference data distribution through CVMFS repositories, robust data transfer, job monitoring, and databases for project tracking. Since the projects inception the experiments under the FIFE umbrella have significantly matured, and present an increasingly complex list of requirements to service providers. To meet these requirements, the FIFE project has been involved in transitioning the Fermilab General Purpose Grid cluster to support a partitionable slot model, expanding the resources available to experiments via the Open Science Grid, assisting with commissioning dedicated high-throughput computing resources for individual experiments, supporting the efforts of the HEP Cloud projects to provision a variety of back end resources, including public clouds and high performance computers, and developing rapid onboarding procedures for new experiments and collaborations. The larger demands also require enhanced job monitoring tools, which the project has developed using such tools as ElasticSearch and Grafana. in helping experiments manage their large-scale production workflows. This group in turn requires a structured service to facilitate smooth management of experiment requests, which FIFE provides in the form of the Production Operations Management Service (POMS). POMS is designed to track and manage requests from the FIFE experiments to run particular workflows, and support troubleshooting and triage in case of problems. Recently a new certificate management infrastructure called Distributed Computing Access with Federated Identities (DCAFI) has been put in place that has eliminated our dependence on a Fermilab-specific third-party Certificate Authority service and better accommodates FIFE collaborators without a Fermilab Kerberos account. DCAFI integrates the existing InCommon federated identity infrastructure, CILogon Basic CA, and a MyProxy service using a new general purpose open source tool. We will discuss the general FIFE onboarding strategy, progress in expanding FIFE experiments presence on the Open Science Grid, new tools for job monitoring, the POMS service, and the DCAFI project.

An Undergraduate Experiment in Alarm System Design.

ERIC Educational Resources Information Center

Martini, R. A.; And Others

1988-01-01

Describes an experiment involving data acquisition by a computer, digital signal transmission from the computer to a digital logic circuit and signal interpretation by this circuit. The system is being used at the Illinois Institute of Technology. Discusses the fundamental concepts involved. Demonstrates the alarm experiment as it is used in…

Remote Viewing and Computer Communications--An Experiment.

ERIC Educational Resources Information Center

Vallee, Jacques

1988-01-01

A series of remote viewing experiments were run with 12 participants who communicated through a computer conferencing network. The correct target sample was identified in 8 out of 33 cases. This represented more than double the pure chance expectation. Appendices present protocol, instructions, and results of the experiments. (Author/YP)

Two Computer-Assisted Experiments

ERIC Educational Resources Information Center

Kraftmakher, Yaakov

2013-01-01

Two computer-assisted experiments are described: (i) determination of the speed of ultrasound waves in water and (ii) measurement of the thermal expansion of an aluminum-based alloy. A new data-acquisition system developed by PASCO scientific is used. In both experiments, the "Keep" mode of recording data is employed: the data are…

Tensor methodology and computational geometry in direct computational experiments in fluid mechanics

NASA Astrophysics Data System (ADS)

Degtyarev, Alexander; Khramushin, Vasily; Shichkina, Julia

2017-07-01

The paper considers a generalized functional and algorithmic construction of direct computational experiments in fluid dynamics. Notation of tensor mathematics is naturally embedded in the finite - element operation in the construction of numerical schemes. Large fluid particle, which have a finite size, its own weight, internal displacement and deformation is considered as an elementary computing object. Tensor representation of computational objects becomes strait linear and uniquely approximation of elementary volumes and fluid particles inside them. The proposed approach allows the use of explicit numerical scheme, which is an important condition for increasing the efficiency of the algorithms developed by numerical procedures with natural parallelism. It is shown that advantages of the proposed approach are achieved among them by considering representation of large particles of a continuous medium motion in dual coordinate systems and computing operations in the projections of these two coordinate systems with direct and inverse transformations. So new method for mathematical representation and synthesis of computational experiment based on large particle method is proposed.

Introducing computational thinking through hands-on projects using R with applications to calculus, probability and data analysis

NASA Astrophysics Data System (ADS)

Benakli, Nadia; Kostadinov, Boyan; Satyanarayana, Ashwin; Singh, Satyanand

2017-04-01

The goal of this paper is to promote computational thinking among mathematics, engineering, science and technology students, through hands-on computer experiments. These activities have the potential to empower students to learn, create and invent with technology, and they engage computational thinking through simulations, visualizations and data analysis. We present nine computer experiments and suggest a few more, with applications to calculus, probability and data analysis, which engage computational thinking through simulations, visualizations and data analysis. We are using the free (open-source) statistical programming language R. Our goal is to give a taste of what R offers rather than to present a comprehensive tutorial on the R language. In our experience, these kinds of interactive computer activities can be easily integrated into a smart classroom. Furthermore, these activities do tend to keep students motivated and actively engaged in the process of learning, problem solving and developing a better intuition for understanding complex mathematical concepts.

Spacecraft crew procedures from paper to computers

NASA Technical Reports Server (NTRS)

Oneal, Michael; Manahan, Meera

1991-01-01

Described here is a research project that uses human factors and computer systems knowledge to explore and help guide the design and creation of an effective Human-Computer Interface (HCI) for spacecraft crew procedures. By having a computer system behind the user interface, it is possible to have increased procedure automation, related system monitoring, and personalized annotation and help facilities. The research project includes the development of computer-based procedure system HCI prototypes and a testbed for experiments that measure the effectiveness of HCI alternatives in order to make design recommendations. The testbed will include a system for procedure authoring, editing, training, and execution. Progress on developing HCI prototypes for a middeck experiment performed on Space Shuttle Mission STS-34 and for upcoming medical experiments are discussed. The status of the experimental testbed is also discussed.

Homomorphic encryption experiments on IBM's cloud quantum computing platform

NASA Astrophysics Data System (ADS)

Huang, He-Liang; Zhao, You-Wei; Li, Tan; Li, Feng-Guang; Du, Yu-Tao; Fu, Xiang-Qun; Zhang, Shuo; Wang, Xiang; Bao, Wan-Su

2017-02-01

Quantum computing has undergone rapid development in recent years. Owing to limitations on scalability, personal quantum computers still seem slightly unrealistic in the near future. The first practical quantum computer for ordinary users is likely to be on the cloud. However, the adoption of cloud computing is possible only if security is ensured. Homomorphic encryption is a cryptographic protocol that allows computation to be performed on encrypted data without decrypting them, so it is well suited to cloud computing. Here, we first applied homomorphic encryption on IBM's cloud quantum computer platform. In our experiments, we successfully implemented a quantum algorithm for linear equations while protecting our privacy. This demonstration opens a feasible path to the next stage of development of cloud quantum information technology.

The use of instant medical history in a rural clinic. Case study of the use of computers in an Arkansas physician's office.

PubMed

Pierce, B

2000-05-01

This study evaluated the acceptance of using computers to take a medical history by rural Arkansas patients. Sex, age, race, education, previous computer experience and owning a computer were used as variables. Patients were asked a series of questions to rate their comfort level with using a computer to take their medical history. Comfort ratings ranged from 30 to 45, with a mean of 36.8 (SEM = 0.67). Neither sex, race, age, education, owning a personal computer, nor prior computer experience had a significant effect on the comfort rating. This study helps alleviate one of the concerns--patient acceptance--about the increasing use of computers in practicing medicine.

Note-Taking with Computers: Exploring Alternative Strategies for Improved Recall

ERIC Educational Resources Information Center

Bui, Dung C.; Myerson, Joel; Hale, Sandra

2013-01-01

Three experiments examined note-taking strategies and their relation to recall. In Experiment 1, participants were instructed either to take organized lecture notes or to try and transcribe the lecture, and they either took their notes by hand or typed them into a computer. Those instructed to transcribe the lecture using a computer showed the…

Task-Relevant Sound and User Experience in Computer-Mediated Firefighter Training

ERIC Educational Resources Information Center

Houtkamp, Joske M.; Toet, Alexander; Bos, Frank A.

2012-01-01

The authors added task-relevant sounds to a computer-mediated instructor in-the-loop virtual training for firefighter commanders in an attempt to raise the engagement and arousal of the users. Computer-mediated training for crew commanders should provide a sensory experience that is sufficiently intense to make the training viable and effective.…

Using Educational Computer Games in the Classroom: Science Teachers' Experiences, Attitudes, Perceptions, Concerns, and Support Needs

ERIC Educational Resources Information Center

An, Yun-Jo; Haynes, Linda; D'Alba, Adriana; Chumney, Frances

2016-01-01

Science teachers' experiences, attitudes, perceptions, concerns, and support needs related to the use of educational computer games were investigated in this study. Data were collected from an online survey, which was completed by 111 science teachers. The results showed that 73% of participants had used computer games in teaching. Participants…

Middle School Girls' Envisioned Future in Computing

ERIC Educational Resources Information Center

Friend, Michelle

2015-01-01

Experience is necessary but not sufficient to cause girls to envision a future career in computing. This study investigated the experiences and attitudes of girls who had taken three years of mandatory computer science classes in an all-girls setting in middle school, measured at the end of eighth grade. The one third of participants who were open…

Blast Load Simulator Experiments for Computational Model Validation: Report 2

DTIC Science & Technology

2017-02-01

repeatability. The uncertainty in the experimental pressures and impulses was evaluated by computing 95% confidence intervals on the results. DISCLAIMER: The...Experiment uncertainty The uncertainty in the experimental pressure and impulse was evaluated for the five replicate experiments for which, as closely as...comparisons were made among the replicated experiments to evaluate repeatability. The uncertainty in the experimental pressures and impulses was

Organizing the History of Computing

NASA Astrophysics Data System (ADS)

Misa, Thomas J.

This paper tries to distill some of the ‘lessons learned’ from the Charles Babbage Institute’s quarter-century experience (1980-present) in organizing the history of computing. It draws on the author’s (recent) experience as CBI director; conversations with Arthur Norberg, CBI’s long-time founding director; and papers delivered at a special symposium appraising CBI’s role in computing history, which appeared in the IEEE Annals of the History of Computing 29 no. 4 (October-December 2007).

Prevalence and Correlates of Problematic Internet Experiences and Computer-Using Time: A Two-Year Longitudinal Study in Korean School Children

PubMed Central

Stewart, Robert; Lee, Ju-Yeon; Kim, Jae-Min; Kim, Sung-Wan; Shin, Il-Seon; Yoon, Jin-Sang

2014-01-01

Objective To measure the prevalence of and factors associated with online inappropriate sexual exposure, cyber-bullying victimisation, and computer-using time in early adolescence. Methods A two-year, prospective school survey was performed with 1,173 children aged 13 at baseline. Data collected included demographic factors, bullying experience, depression, anxiety, coping strategies, self-esteem, psychopathology, attention-deficit hyperactivity disorder symptoms, and school performance. These factors were investigated in relation to problematic Internet experiences and computer-using time at age 15. Results The prevalence of online inappropriate sexual exposure, cyber-bullying victimisation, academic-purpose computer overuse, and game-purpose computer overuse was 31.6%, 19.2%, 8.5%, and 21.8%, respectively, at age 15. Having older siblings, more weekly pocket money, depressive symptoms, anxiety symptoms, and passive coping strategy were associated with reported online sexual harassment. Male gender, depressive symptoms, and anxiety symptoms were associated with reported cyber-bullying victimisation. Female gender was associated with academic-purpose computer overuse, while male gender, lower academic level, increased height, and having older siblings were associated with game-purpose computer-overuse. Conclusion Different environmental and psychological factors predicted different aspects of problematic Internet experiences and computer-using time. This knowledge is important for framing public health interventions to educate adolescents about, and prevent, internet-derived problems. PMID:24605120

The Effects of Korean Learners' Online Experiences on Their English Writing

ERIC Educational Resources Information Center

Park, Chanho; Cho, Sookyung

2014-01-01

This study aims to examine the effects of the online writing experiences of English as a foreign language (EFL) learners on their self-efficacy, attitudes, and performance in a computer-mediated writing classroom (CMC). Although the close relationship between students' computer experiences and class performance has been positively confirmed in…

Methodological Potential of Computer Experiment in Teaching Mathematics at University

ERIC Educational Resources Information Center

Lin, Kequan; Sokolova, Anna Nikolaevna; Vlasova, Vera K.

2017-01-01

The study is relevant due to the opportunity of increasing efficiency of teaching mathematics at university through integration of students of computer experiment conducted with the use of IT in this process. The problem of there search is defined by a contradiction between great potential opportunities of mathematics experiment for motivating and…

Inquiry Based-Computational Experiment, Acquisition of Threshold Concepts and Argumentation in Science and Mathematics Education

ERIC Educational Resources Information Center

Psycharis, Sarantos

2016-01-01

Computational experiment approach considers models as the fundamental instructional units of Inquiry Based Science and Mathematics Education (IBSE) and STEM Education, where the model take the place of the "classical" experimental set-up and simulation replaces the experiment. Argumentation in IBSE and STEM education is related to the…

Analyzing the security of an existing computer system

NASA Technical Reports Server (NTRS)

Bishop, M.

1986-01-01

Most work concerning secure computer systems has dealt with the design, verification, and implementation of provably secure computer systems, or has explored ways of making existing computer systems more secure. The problem of locating security holes in existing systems has received considerably less attention; methods generally rely on thought experiments as a critical step in the procedure. The difficulty is that such experiments require that a large amount of information be available in a format that makes correlating the details of various programs straightforward. This paper describes a method of providing such a basis for the thought experiment by writing a special manual for parts of the operating system, system programs, and library subroutines.

Closed-Loop HIRF Experiments Performed on a Fault Tolerant Flight Control Computer

NASA Technical Reports Server (NTRS)

Belcastro, Celeste M.

1997-01-01

ABSTRACT Closed-loop HIRF experiments were performed on a fault tolerant flight control computer (FCC) at the NASA Langley Research Center. The FCC used in the experiments was a quad-redundant flight control computer executing B737 Autoland control laws. The FCC was placed in one of the mode-stirred reverberation chambers in the HIRF Laboratory and interfaced to a computer simulation of the B737 flight dynamics, engines, sensors, actuators, and atmosphere in the Closed-Loop Systems Laboratory. Disturbances to the aircraft associated with wind gusts and turbulence were simulated during tests. Electrical isolation between the FCC under test and the simulation computer was achieved via a fiber optic interface for the analog and discrete signals. Closed-loop operation of the FCC enabled flight dynamics and atmospheric disturbances affecting the aircraft to be represented during tests. Upset was induced in the FCC as a result of exposure to HIRF, and the effect of upset on the simulated flight of the aircraft was observed and recorded. This paper presents a description of these closed- loop HIRF experiments, upset data obtained from the FCC during these experiments, and closed-loop effects on the simulated flight of the aircraft.

Computer Experiences, Self-Efficacy and Knowledge of Students Enrolled in Introductory University Agriculture Courses.

ERIC Educational Resources Information Center

Johnson, Donald M.; Ferguson, James A.; Lester, Melissa L.

1999-01-01

Of 175 freshmen agriculture students, 74% had prior computer courses, 62% owned computers. The number of computer topics studied predicted both computer self-efficacy and computer knowledge. A substantial positive correlation was found between self-efficacy and computer knowledge. (SK)

Assessment of Computer Literacy of Nurses in Lesotho.

PubMed

Mugomeri, Eltony; Chatanga, Peter; Maibvise, Charles; Masitha, Matseliso

2016-11-01

Health systems worldwide are moving toward use of information technology to improve healthcare delivery. However, this requires basic computer skills. This study assessed the computer literacy of nurses in Lesotho using a cross-sectional quantitative approach. A structured questionnaire with 32 standardized computer skills was distributed to 290 randomly selected nurses in Maseru District. Univariate and multivariate logistic regression analyses in Stata 13 were performed to identify factors associated with having inadequate computer skills. Overall, 177 (61%) nurses scored below 16 of the 32 skills assessed. Finding hyperlinks on Web pages (63%), use of advanced search parameters (60.2%), and downloading new software (60.1%) proved to be challenging to the highest proportions of nurses. Age, sex, year of obtaining latest qualification, computer experience, and work experience were significantly (P < .05) associated with inadequate computer skills in univariate analysis. However, in multivariate analyses, sex (P = .001), year of obtaining latest qualification (P = .011), and computer experience (P < .001) emerged as significant factors. The majority of nurses in Lesotho have inadequate computer skills, and this is significantly associated with having many years since obtaining their latest qualification, being female, and lack of exposure to computers. These factors should be considered during planning of training curriculum for nurses in Lesotho.

Comparison of Computational Results with a Low-g, Nitrogen Slosh and Boiling Experiment

NASA Technical Reports Server (NTRS)

Stewart, Mark; Moder, Jeff

2015-01-01

The proposed paper will compare a fluid/thermal simulation, in FLUENT, with a low-g, nitrogen slosh experiment. The French Space Agency, CNES, performed cryogenic nitrogen experiments in several zero gravity aircraft campaigns. The computational results have been compared with high-speed photographic data, pressure data, and temperature data from sensors on the axis of the cylindrically shaped tank. The comparison between these experimental and computational results is generally favorable: the initial temperature stratification is in good agreement, and the two-phase fluid motion is qualitatively captured.

In Search of the Physics: The Interplay of Experiment and Computation in Airframe Noise Research: Flap-Edge Noise

NASA Technical Reports Server (NTRS)

Streett, C. L.; Lockard, D. P.; Singer, B. A.; Khorrami, M. R.; Choudhari, M. M.

2003-01-01

The LaRC investigative process for airframe noise has proven to be a useful guide for elucidation of the physics of flow-induced noise generation over the last five years. This process, relying on a close interplay between experiment and computation, is described and demonstrated here on the archetypal problem of flap-edge noise. Some detailed results from both experiment and computation are shown to illustrate the process, and a description of the multi-source physics seen in this problem is conjectured.

Linear programming computational experience with onyx

DOE Office of Scientific and Technical Information (OSTI.GOV)

Atrek, E.

1994-12-31

ONYX is a linear programming software package based on an efficient variation of the gradient projection method. When fully configured, it is intended for application to industrial size problems. While the computational experience is limited at the time of this abstract, the technique is found to be robust and competitive with existing methodology in terms of both accuracy and speed. An overview of the approach is presented together with a description of program capabilities, followed by a discussion of up-to-date computational experience with the program. Conclusions include advantages of the approach and envisioned future developments.

Communicative Language Testing: Implications for Computer Based Language Testing in French for Specific Purposes

ERIC Educational Resources Information Center

García Laborda, Jesús; López Santiago, Mercedes; Otero de Juan, Nuria; Álvarez Álvarez, Alfredo

2014-01-01

Current evolutions of language testing have led to integrating computers in FSP assessments both in oral and written communicative tasks. This paper deals with two main issues: learners' expectations about the types of questions in FSP computer based assessments and the relation with their own experience. This paper describes the experience of 23…

An Empirical Study of User Experience on Touch Mice

ERIC Educational Resources Information Center

Chou, Jyh Rong

2016-01-01

The touch mouse is a new type of computer mouse that provides users with a new way of touch-based environment to interact with computers. For more than a decade, user experience (UX) has grown into a core concept of human-computer interaction (HCI), describing a user's perceptions and responses that result from the use of a product in a particular…

A Comparative Study of University of Wisconsin-Stout Freshmen and Senior Education Major's Computing and Internet Technology Skills/Knowledge and Associated Learning Experiences

ERIC Educational Resources Information Center

Sveum, Evan Charles

2010-01-01

A study comparing University of Wisconsin-Stout freshmen and senior education majors' computing and Internet technology skills/knowledge and associated learning experiences was conducted. Instruments used in this study included the IC[superscript 3][R] Exam by Certiport, Inc. and the investigator's Computing and Internet Skills Learning…

Experience with Aero- and Fluid-Dynamic Testing for Engineering and CFD Validation

NASA Technical Reports Server (NTRS)

Ross, James C.

2016-01-01

Ever since computations have been used to simulate aerodynamics the need to ensure that the computations adequately represent real life has followed. Many experiments have been performed specifically for validation and as computational methods have improved, so have the validation experiments. Validation is also a moving target because computational methods improve requiring validation for the new aspect of flow physics that the computations aim to capture. Concurrently, new measurement techniques are being developed that can help capture more detailed flow features pressure sensitive paint (PSP) and particle image velocimetry (PIV) come to mind. This paper will present various wind-tunnel tests the author has been involved with and how they were used for validation of various kinds of CFD. A particular focus is the application of advanced measurement techniques to flow fields (and geometries) that had proven to be difficult to predict computationally. Many of these difficult flow problems arose from engineering and development problems that needed to be solved for a particular vehicle or research program. In some cases the experiments required to solve the engineering problems were refined to provide valuable CFD validation data in addition to the primary engineering data. All of these experiments have provided physical insight and validation data for a wide range of aerodynamic and acoustic phenomena for vehicles ranging from tractor-trailers to crewed spacecraft.

Knowledge and utilization of computer-software for statistics among Nigerian dentists.

PubMed

Chukwuneke, F N; Anyanechi, C E; Obiakor, A O; Amobi, O; Onyejiaka, N; Alamba, I

2013-01-01

The use of computer soft ware for generation of statistic analysis has transformed health information and data to simplest form in the areas of access, storage, retrieval and analysis in the field of research. This survey therefore was carried out to assess the level of knowledge and utilization of computer software for statistical analysis among dental researchers in eastern Nigeria. Questionnaires on the use of computer software for statistical analysis were randomly distributed to 65 practicing dental surgeons of above 5 years experience in the tertiary academic hospitals in eastern Nigeria. The focus was on: years of clinical experience; research work experience; knowledge and application of computer generated software for data processing and stastistical analysis. Sixty-two (62/65; 95.4%) of these questionnaires were returned anonymously, which were used in our data analysis. Twenty-nine (29/62; 46.8%) respondents fall within those with 5-10 years of clinical experience out of which none has completed the specialist training programme. Practitioners with above 10 years clinical experiences were 33 (33/62; 53.2%) out of which 15 (15/33; 45.5%) are specialists representing 24.2% (15/62) of the total number of respondents. All the 15 specialists are actively involved in research activities and only five (5/15; 33.3%) can utilize software statistical analysis unaided. This study has i dentified poor utilization of computer software for statistic analysis among dental researchers in eastern Nigeria. This is strongly associated with lack of exposure on the use of these software early enough especially during the undergraduate training. This call for introduction of computer training programme in dental curriculum to enable practitioners develops the attitude of using computer software for their research.

Federated data storage system prototype for LHC experiments and data intensive science

NASA Astrophysics Data System (ADS)

Kiryanov, A.; Klimentov, A.; Krasnopevtsev, D.; Ryabinkin, E.; Zarochentsev, A.

2017-10-01

Rapid increase of data volume from the experiments running at the Large Hadron Collider (LHC) prompted physics computing community to evaluate new data handling and processing solutions. Russian grid sites and universities’ clusters scattered over a large area aim at the task of uniting their resources for future productive work, at the same time giving an opportunity to support large physics collaborations. In our project we address the fundamental problem of designing a computing architecture to integrate distributed storage resources for LHC experiments and other data-intensive science applications and to provide access to data from heterogeneous computing facilities. Studies include development and implementation of federated data storage prototype for Worldwide LHC Computing Grid (WLCG) centres of different levels and University clusters within one National Cloud. The prototype is based on computing resources located in Moscow, Dubna, Saint Petersburg, Gatchina and Geneva. This project intends to implement a federated distributed storage for all kind of operations such as read/write/transfer and access via WAN from Grid centres, university clusters, supercomputers, academic and commercial clouds. The efficiency and performance of the system are demonstrated using synthetic and experiment-specific tests including real data processing and analysis workflows from ATLAS and ALICE experiments, as well as compute-intensive bioinformatics applications (PALEOMIX) running on supercomputers. We present topology and architecture of the designed system, report performance and statistics for different access patterns and show how federated data storage can be used efficiently by physicists and biologists. We also describe how sharing data on a widely distributed storage system can lead to a new computing model and reformations of computing style, for instance how bioinformatics program running on supercomputers can read/write data from the federated storage.

Virtual deposition plant

NASA Astrophysics Data System (ADS)

Tikhonravov, Alexander

2005-09-01

A general structure of the software for computational manufacturing experiments is discussed. It is shown that computational experiments can be useful for checking feasibility properties of theoretical designs and for finding the most practical theoretical design for a given production environment.

Computer-Based Experiments to Measure RC.

ERIC Educational Resources Information Center

Hart, Francis X.

2000-01-01

Finds that few electricity and magnetism experiments make use of computers for data acquisition. Reports on the use of a Vernier system for the measurement of the RC time constant for the charging and discharging of a capacitor. (CCM)

Computer Series, 17: Bits and Pieces, 5.

ERIC Educational Resources Information Center

Moore, John W., Ed.

1981-01-01

Contains short descriptions of computer programs or hardware that simulate laboratory instruments or results of kinetics experiments, including ones that include experiment error, numerical simulation, first-order kinetic mechanisms, a game for decisionmaking, and simulated mass spectrophotometers. (CS)

Assessment of CFD Estimation of Aerodynamic Characteristics of Basic Reusable Rocket Configurations

NASA Astrophysics Data System (ADS)

Fujimoto, Keiichiro; Fujii, Kozo

Flow-fields around the basic SSTO-rocket configurations are numerically simulated by the Reynolds-averaged Navier-Stokes (RANS) computations. Simulations of the Apollo-like configuration is first carried out, where the results are compared with NASA experiments and the prediction ability of the RANS simulation is discussed. The angle of attack of the freestream ranges from 0° to 180° and the freestream Mach number ranges from 0.7 to 2.0. Computed aerodynamic coefficients for the Apollo-like configuration agree well with the experiments under a wide range of flow conditions. The flow simulations around the slender Apollo-type configuration are carried out next and the results are compared with the experiments. Computed aerodynamic coefficients also agree well with the experiments. Flow-fields are dominated by the three-dimensional massively separated flow, which should be captured for accurate aerodynamic prediction. Grid refinement effects on the computed aerodynamic coefficients are investigated comprehensively.

DSMC Simulations of Hypersonic Flows and Comparison With Experiments

NASA Technical Reports Server (NTRS)

Moss, James N.; Bird, Graeme A.; Markelov, Gennady N.

2004-01-01

This paper presents computational results obtained with the direct simulation Monte Carlo (DSMC) method for several biconic test cases in which shock interactions and flow separation-reattachment are key features of the flow. Recent ground-based experiments have been performed for several biconic configurations, and surface heating rate and pressure measurements have been proposed for code validation studies. The present focus is to expand on the current validating activities for a relatively new DSMC code called DS2V that Bird (second author) has developed. Comparisons with experiments and other computations help clarify the agreement currently being achieved between computations and experiments and to identify the range of measurement variability of the proposed validation data when benchmarked with respect to the current computations. For the test cases with significant vibrational nonequilibrium, the effect of the vibrational energy surface accommodation on heating and other quantities is demonstrated.

Characterization of High Explosives and Other Energetic Compounds by Computational Chemistry and Molecular Modeling: Experiments for Undergraduate Curriculum

ERIC Educational Resources Information Center

Bumpus, John A.; Lewis, Anne; Stotts, Corey; Cramer, Christopher J.

2007-01-01

Experiments suited for the undergraduate instructional laboratory in which the heats of formation of several aliphatic and aromatic compounds are calculated, are described. The experiments could be used to introduce students to commercially available computational chemistry and its thermodynamics, while assess and compare the energy content of…

Computer Programs for Chemistry Experiments I and II.

ERIC Educational Resources Information Center

Reynard, Dale C.

This unit of instruction includes nine laboratory experiments. All of the experiments are from the D.C. Health Revision of the Chemical Education Materials Study (CHEMS) with one exception. Program six is the lab from the original version of the CHEMS program. Each program consists of three parts (1) the lab and computer hints, (2) the description…

The ZAP Project: Designing Interactive Computer Tools for Learning Psychology

ERIC Educational Resources Information Center

Hulshof, Casper; Eysink, Tessa; de Jong, Ton

2006-01-01

In the ZAP project, a set of interactive computer programs called "ZAPs" was developed. The programs were designed in such a way that first-year students experience psychological phenomena in a vivid and self-explanatory way. Students can either take the role of participant in a psychological experiment, they can experience phenomena themselves,…

When static media promote active learning: annotated illustrations versus narrated animations in multimedia instruction.

PubMed

Mayer, Richard E; Hegarty, Mary; Mayer, Sarah; Campbell, Julie

2005-12-01

In 4 experiments, students received a lesson consisting of computer-based animation and narration or a lesson consisting of paper-based static diagrams and text. The lessons used the same words and graphics in the paper-based and computer-based versions to explain the process of lightning formation (Experiment 1), how a toilet tank works (Experiment 2), how ocean waves work (Experiment 3), and how a car's braking system works (Experiment 4). On subsequent retention and transfer tests, the paper group performed significantly better than the computer group on 4 of 8 comparisons, and there was no significant difference on the rest. These results support the static media hypothesis, in which static illustrations with printed text reduce extraneous processing and promote germane processing as compared with narrated animations.

Static Computer Memory Integrity Testing (SCMIT): An experiment flown on STS-40 as part of GAS payload G-616

NASA Technical Reports Server (NTRS)

Hancock, Thomas

1993-01-01

This experiment investigated the integrity of static computer memory (floppy disk media) when exposed to the environment of low earth orbit. The experiment attempted to record soft-event upsets (bit-flips) in static computer memory. Typical conditions that exist in low earth orbit that may cause soft-event upsets include: cosmic rays, low level background radiation, charged fields, static charges, and the earth's magnetic field. Over the years several spacecraft have been affected by soft-event upsets (bit-flips), and these events have caused a loss of data or affected spacecraft guidance and control. This paper describes a commercial spin-off that is being developed from the experiment.

Quantum chemistry simulation on quantum computers: theories and experiments.

PubMed

Lu, Dawei; Xu, Boruo; Xu, Nanyang; Li, Zhaokai; Chen, Hongwei; Peng, Xinhua; Xu, Ruixue; Du, Jiangfeng

2012-07-14

It has been claimed that quantum computers can mimic quantum systems efficiently in the polynomial scale. Traditionally, those simulations are carried out numerically on classical computers, which are inevitably confronted with the exponential growth of required resources, with the increasing size of quantum systems. Quantum computers avoid this problem, and thus provide a possible solution for large quantum systems. In this paper, we first discuss the ideas of quantum simulation, the background of quantum simulators, their categories, and the development in both theories and experiments. We then present a brief introduction to quantum chemistry evaluated via classical computers followed by typical procedures of quantum simulation towards quantum chemistry. Reviewed are not only theoretical proposals but also proof-of-principle experimental implementations, via a small quantum computer, which include the evaluation of the static molecular eigenenergy and the simulation of chemical reaction dynamics. Although the experimental development is still behind the theory, we give prospects and suggestions for future experiments. We anticipate that in the near future quantum simulation will become a powerful tool for quantum chemistry over classical computations.

Post-Fisherian Experimentation: From Physical to Virtual

DOE PAGES

Jeff Wu, C. F.

2014-04-24

Fisher's pioneering work in design of experiments has inspired further work with broader applications, especially in industrial experimentation. Three topics in physical experiments are discussed: principles of effect hierarchy, sparsity, and heredity for factorial designs, a new method called CME for de-aliasing aliased effects, and robust parameter design. The recent emergence of virtual experiments on a computer is reviewed. Here, some major challenges in computer experiments, which must go beyond Fisherian principles, are outlined.

Accelerated Application Development: The ORNL Titan Experience

DOE PAGES

Joubert, Wayne; Archibald, Richard K.; Berrill, Mark A.; ...

2015-05-09

The use of computational accelerators such as NVIDIA GPUs and Intel Xeon Phi processors is now widespread in the high performance computing community, with many applications delivering impressive performance gains. However, programming these systems for high performance, performance portability and software maintainability has been a challenge. In this paper we discuss experiences porting applications to the Titan system. Titan, which began planning in 2009 and was deployed for general use in 2013, was the first multi-petaflop system based on accelerator hardware. To ready applications for accelerated computing, a preparedness effort was undertaken prior to delivery of Titan. In this papermore » we report experiences and lessons learned from this process and describe how users are currently making use of computational accelerators on Titan.« less

Accelerated application development: The ORNL Titan experience

DOE Office of Scientific and Technical Information (OSTI.GOV)

Joubert, Wayne; Archibald, Rick; Berrill, Mark

2015-08-01

The use of computational accelerators such as NVIDIA GPUs and Intel Xeon Phi processors is now widespread in the high performance computing community, with many applications delivering impressive performance gains. However, programming these systems for high performance, performance portability and software maintainability has been a challenge. In this paper we discuss experiences porting applications to the Titan system. Titan, which began planning in 2009 and was deployed for general use in 2013, was the first multi-petaflop system based on accelerator hardware. To ready applications for accelerated computing, a preparedness effort was undertaken prior to delivery of Titan. In this papermore » we report experiences and lessons learned from this process and describe how users are currently making use of computational accelerators on Titan.« less

View of MISSE-8 taken during a session of EVA

NASA Image and Video Library

2011-07-12

ISS028-E-016111 (12 July 2011) --- This close-up image, recorded during a July 12 spacewalk, shows the Materials on International Space Station Experiment - 8 (MISSE-8). The experiment package is a test bed for materials and computing elements attached to the outside of the orbiting complex. These materials and computing elements are being evaluated for the effects of atomic oxygen, ultraviolet, direct sunlight, radiation, and extremes of heat and cold. This experiment allows the development and testing of new materials and computing elements that can better withstand the rigors of space environments. Results will provide a better understanding of the durability of various materials and computing elements when they are exposed to the space environment, with applications in the design of future spacecraft.

Considerations for Explosively Driven Conical Shock Tube Design: Computations and Experiments

DTIC Science & Technology

2017-02-16

ARL-TR-7953 ● FEB 2017 US Army Research Laboratory Considerations for Explosively Driven Conical Shock Tube Design : Computations...The findings in this report are not to be construed as an official Department of the Army position unless so designated by other authorized...Considerations for Explosively Driven Conical Shock Tube Designs : Computations and Experiments by Joel B Stewart Weapons and Materials Research Directorate

Teachers' Experiences of Using Eye Gaze-Controlled Computers for Pupils with Severe Motor Impairments and without Speech

ERIC Educational Resources Information Center

Rytterström, Patrik; Borgestig, Maria; Hemmingsson, Helena

2016-01-01

The purpose of this study is to explore teachers' experiences of using eye gaze-controlled computers with pupils with severe disabilities. Technology to control a computer with eye gaze is a fast growing field and has promising implications for people with severe disabilities. This is a new assistive technology and a new learning situation for…

Research and Teaching: Computational Methods in General Chemistry--Perceptions of Programming, Prior Experience, and Student Outcomes

ERIC Educational Resources Information Center

Wheeler, Lindsay B.; Chiu, Jennie L.; Grisham, Charles M.

2016-01-01

This article explores how integrating computational tools into a general chemistry laboratory course can influence student perceptions of programming and investigates relationships among student perceptions, prior experience, and student outcomes.

A distributed computing environment with support for constraint-based task scheduling and scientific experimentation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ahrens, J.P.; Shapiro, L.G.; Tanimoto, S.L.

1997-04-01

This paper describes a computing environment which supports computer-based scientific research work. Key features include support for automatic distributed scheduling and execution and computer-based scientific experimentation. A new flexible and extensible scheduling technique that is responsive to a user`s scheduling constraints, such as the ordering of program results and the specification of task assignments and processor utilization levels, is presented. An easy-to-use constraint language for specifying scheduling constraints, based on the relational database query language SQL, is described along with a search-based algorithm for fulfilling these constraints. A set of performance studies show that the environment can schedule and executemore » program graphs on a network of workstations as the user requests. A method for automatically generating computer-based scientific experiments is described. Experiments provide a concise method of specifying a large collection of parameterized program executions. The environment achieved significant speedups when executing experiments; for a large collection of scientific experiments an average speedup of 3.4 on an average of 5.5 scheduled processors was obtained.« less

Computing at DESY — current setup, trends and strategic directions

NASA Astrophysics Data System (ADS)

Ernst, Michael

1998-05-01

Since the HERA experiments H1 and ZEUS started data taking in '92, the computing environment at DESY has changed dramatically. Running a mainframe centred computing for more than 20 years, DESY switched to a heterogeneous, fully distributed computing environment within only about two years in almost every corner where computing has its applications. The computing strategy was highly influenced by the needs of the user community. The collaborations are usually limited by current technology and their ever increasing demands is the driving force for central computing to always move close to the technology edge. While DESY's central computing has a multidecade experience in running Central Data Recording/Central Data Processing for HEP experiments, the most challenging task today is to provide for clear and homogeneous concepts in the desktop area. Given that lowest level commodity hardware draws more and more attention, combined with the financial constraints we are facing already today, we quickly need concepts for integrated support of a versatile device which has the potential to move into basically any computing area in HEP. Though commercial solutions, especially addressing the PC management/support issues, are expected to come to market in the next 2-3 years, we need to provide for suitable solutions now. Buying PC's at DESY currently at a rate of about 30/month will otherwise absorb any available manpower in central computing and still will leave hundreds of unhappy people alone. Though certainly not the only region, the desktop issue is one of the most important one where we need HEP-wide collaboration to a large extent, and right now. Taking into account that there is traditionally no room for R&D at DESY, collaboration, meaning sharing experience and development resources within the HEP community, is a predominant factor for us.

Processing of the WLCG monitoring data using NoSQL

NASA Astrophysics Data System (ADS)

Andreeva, J.; Beche, A.; Belov, S.; Dzhunov, I.; Kadochnikov, I.; Karavakis, E.; Saiz, P.; Schovancova, J.; Tuckett, D.

2014-06-01

The Worldwide LHC Computing Grid (WLCG) today includes more than 150 computing centres where more than 2 million jobs are being executed daily and petabytes of data are transferred between sites. Monitoring the computing activities of the LHC experiments, over such a huge heterogeneous infrastructure, is extremely demanding in terms of computation, performance and reliability. Furthermore, the generated monitoring flow is constantly increasing, which represents another challenge for the monitoring systems. While existing solutions are traditionally based on Oracle for data storage and processing, recent developments evaluate NoSQL for processing large-scale monitoring datasets. NoSQL databases are getting increasingly popular for processing datasets at the terabyte and petabyte scale using commodity hardware. In this contribution, the integration of NoSQL data processing in the Experiment Dashboard framework is described along with first experiences of using this technology for monitoring the LHC computing activities.

Student computer attitudes, experience and perceptions about the use of two software applications in Building Engineering

NASA Astrophysics Data System (ADS)

Chiner, Esther; Garcia-Vera, Victoria E.

2017-11-01

The purpose of this study was to examine students' computer attitudes and experience, as well as students' perceptions about the use of two specific software applications (Google Drive Spreadsheets and Arquimedes) in the Building Engineering context. The relationships among these variables were also examined. Ninety-two students took part in this study. Results suggest that students hold favourable computer attitudes. Moreover, it was found a significant positive relationship among students' attitudes and their computer experience. Findings also show that students find Arquimedes software more useful and with higher output quality than Google Drive Spreadsheets, while the latter is perceived to be easier to use. Regarding the relationship among students' attitudes towards the use of computers and their perceptions about the use of both software applications, only a significant positive relationship in the case of Arquimedes was found. Findings are discussed in terms of its implications for practice and further research.

Spacelab experiment computer study. Volume 1: Executive summary (presentation)

NASA Technical Reports Server (NTRS)

Lewis, J. L.; Hodges, B. C.; Christy, J. O.

1976-01-01

A quantitative cost for various Spacelab flight hardware configurations is provided along with varied software development options. A cost analysis of Spacelab computer hardware and software is presented. The cost study is discussed based on utilization of a central experiment computer with optional auxillary equipment. Groundrules and assumptions used in deriving the costing methods for all options in the Spacelab experiment study are presented. The groundrules and assumptions, are analysed and the options along with their cost considerations, are discussed. It is concluded that Spacelab program cost for software development and maintenance is independent of experimental hardware and software options, that distributed standard computer concept simplifies software integration without a significant increase in cost, and that decisions on flight computer hardware configurations should not be made until payload selection for a given mission and a detailed analysis of the mission requirements are completed.

Computer Anxiety and Student Teachers: Interrelationships between Computer Anxiety, Demographic Variables and an Intervention Strategy.

ERIC Educational Resources Information Center

McInerney, Valentina; And Others

This study examined the effects of increased computing experience on the computer anxiety of 101 first year preservice teacher education students at a regional university in Australia. Three instruments measuring computer anxiety and attitudes--the Computer Anxiety Rating Scale (CARS), Attitudes Towards Computers Scale (ATCS), and Computer…

Computer-Related Success and Failure: A Longitudinal Field Study of the Factors Influencing Computer-Related Performance.

ERIC Educational Resources Information Center

Rozell, E. J.; Gardner, W. L., III

1999-01-01

A model of the intrapersonal processes impacting computer-related performance was tested using data from 75 manufacturing employees in a computer training course. Gender, computer experience, and attributional style were predictive of computer attitudes, which were in turn related to computer efficacy, task-specific performance expectations, and…

Enabling Grid Computing resources within the KM3NeT computing model

NASA Astrophysics Data System (ADS)

Filippidis, Christos

2016-04-01

KM3NeT is a future European deep-sea research infrastructure hosting a new generation neutrino detectors that - located at the bottom of the Mediterranean Sea - will open a new window on the universe and answer fundamental questions both in particle physics and astrophysics. International collaborative scientific experiments, like KM3NeT, are generating datasets which are increasing exponentially in both complexity and volume, making their analysis, archival, and sharing one of the grand challenges of the 21st century. These experiments, in their majority, adopt computing models consisting of different Tiers with several computing centres and providing a specific set of services for the different steps of data processing such as detector calibration, simulation and data filtering, reconstruction and analysis. The computing requirements are extremely demanding and, usually, span from serial to multi-parallel or GPU-optimized jobs. The collaborative nature of these experiments demands very frequent WAN data transfers and data sharing among individuals and groups. In order to support the aforementioned demanding computing requirements we enabled Grid Computing resources, operated by EGI, within the KM3NeT computing model. In this study we describe our first advances in this field and the method for the KM3NeT users to utilize the EGI computing resources in a simulation-driven use-case.

Computational Analysis of a Prototype Martian Rotorcraft Experiment

NASA Technical Reports Server (NTRS)

Corfeld, Kelly J.; Strawn, Roger C.; Long, Lyle N.

2002-01-01

This paper presents Reynolds-averaged Navier-Stokes calculations for a prototype Martian rotorcraft. The computations are intended for comparison with an ongoing Mars rotor hover test at NASA Ames Research Center. These computational simulations present a new and challenging problem, since rotors that operate on Mars will experience a unique low Reynolds number and high Mach number environment. Computed results for the 3-D rotor differ substantially from 2-D sectional computations in that the 3-D results exhibit a stall delay phenomenon caused by rotational forces along the blade span. Computational results have yet to be compared to experimental data, but computed performance predictions match the experimental design goals fairly well. In addition, the computed results provide a high level of detail in the rotor wake and blade surface aerodynamics. These details provide an important supplement to the expected experimental performance data.

Dropping Out of Computer Science: A Phenomenological Study of Student Lived Experiences in Community College Computer Science

NASA Astrophysics Data System (ADS)

Gilbert-Valencia, Daniel H.

California community colleges contribute alarmingly few computer science degree or certificate earners. While the literature shows clear K-12 impediments to CS matriculation in higher education, very little is known about the experiences of those who overcome initial impediments to CS yet do not persist through to program completion. This phenomenological study explores insights into that specific experience by interviewing underrepresented, low income, first-generation college students who began community college intending to transfer to 4-year institutions majoring in CS but switched to another field and remain enrolled or graduated. This study explores the lived experiences of students facing barriers, their avenues for developing interest in CS, and the persistence support systems they encountered, specifically looking at how students constructed their academic choice from these experiences. The growing diversity within California's population necessitates that experiences specific to underrepresented students be considered as part of this exploration. Ten semi-structured interviews and observations were conducted, transcribed and coded. Artifacts supporting student experiences were also collected. Data was analyzed through a social-constructivist lens to provide insight into experiences and how they can be navigated to create actionable strategies for community college computer science departments wishing to increase student success. Three major themes emerged from this research: (1) students shared pre-college characteristics; (2) faced similar challenges in college CS courses; and (3) shared similar reactions to the "work" of computer science. Results of the study included (1) CS interest development hinged on computer ownership in the home; (2) participants shared characteristics that were ideal for college success but not CS success; and (3) encounters in CS departments produced unique challenges for participants. Though CS interest was and remains abundant, opportunities for learning programming skills before college were non-existent and there were few opportunities in college to build skills or establish a peer support networks. Recommendations for institutional leaders and further research are also provided.

The impact of individual factors on healthcare staff's computer use in psychiatric hospitals.

PubMed

Koivunen, Marita; Välimäki, Maritta; Koskinen, Anita; Staggers, Nancy; Katajisto, Jouko

2009-04-01

The study examines whether individual factors of healthcare staff are associated with computer use in psychiatric hospitals. In addition, factors inhibiting staff's optimal use of computers were explored. Computer applications have developed the content of clinical practice and changed patterns of professional working. Healthcare staff need new capacities to work in clinical practice, including the basic computers skills. Computer use amongst healthcare staff has widely been studied in general, but cogent information is still lacking in psychiatric care. Staff's computer use was assessed using a structured questionnaire (The Staggers Nursing Computer Experience Questionnaire). The study population was healthcare staff working in two psychiatric hospitals in Finland (n = 470, response rate = 59%). The data were analysed with descriptive statistics and manova with main effects and two-way interaction effects of six individual factors. Nurses who had more experience of computer use or of the implementation processes of computer systems were more motivated to use computers than those who had less experience of these issues. Males and administrative personnel who were younger had also participated more often than women in implementation processes of computer systems. The most significant factor inhibiting the use of computers was lack of interest in them. In psychiatric hospitals, more direct attention should focus on staff's capacities to use computers and to increase their understanding of the benefits in clinical care, especially for women and ageing staff working in psychiatric hospitals. To avoid exclusion amongst healthcare personnel in information society and to ensure that they have capacities to guide patients on how to use computers or to evaluate the quality of health information on the web, staff's capacities and motivation to use computers in mental health and psychiatric nursing should be ensured.

Universe creation on a computer

NASA Astrophysics Data System (ADS)

McCabe, Gordon

The purpose of this paper is to provide an account of the epistemology and metaphysics of universe creation on a computer. The paper begins with F.J. Tipler's argument that our experience is indistinguishable from the experience of someone embedded in a perfect computer simulation of our own universe, hence we cannot know whether or not we are part of such a computer program ourselves. Tipler's argument is treated as a special case of epistemological scepticism, in a similar vein to 'brain-in-a-vat' arguments. It is argued that Tipler's hypothesis that our universe is a program running on a digital computer in another universe, generates empirical predictions, and is therefore a falsifiable hypothesis. The computer program hypothesis is also treated as a hypothesis about what exists beyond the physical world, and is compared with Kant's metaphysics of noumena. It is argued that if our universe is a program running on a digital computer, then our universe must have compact spatial topology, and the possibilities of observationally testing this prediction are considered. The possibility of testing the computer program hypothesis with the value of the density parameter Ω0 is also analysed. The informational requirements for a computer to represent a universe exactly and completely are considered. Consequent doubt is thrown upon Tipler's claim that if a hierarchy of computer universes exists, we would not be able to know which 'level of implementation' our universe exists at. It is then argued that a digital computer simulation of a universe, or any other physical system, does not provide a realisation of that universe or system. It is argued that a digital computer simulation of a physical system is not objectively related to that physical system, and therefore cannot exist as anything else other than a physical process occurring upon the components of the computer. It is concluded that Tipler's sceptical hypothesis, and a related hypothesis from Bostrom, cannot be true: it is impossible that our own experience is indistinguishable from the experience of somebody embedded in a digital computer simulation because it is impossible for anybody to be embedded in a digital computer simulation.

Design Experiments in Japanese Elementary Science Education with Computer Support for Collaborative Learning: Hypothesis Testing and Collaborative Construction

ERIC Educational Resources Information Center

Oshima, Jun; Oshima, Ritsuko; Murayama, Isao; Inagaki, Shigenori; Takenaka, Makiko; Nakayama, Hayashi; Yamaguchi, Etsuji

2004-01-01

This paper reports design experiments on two Japanese elementary science lesson units in a sixth-grade classroom supported by computer support for collaborative learning (CSCL) technology as a collaborative reflection tool. We took different approaches in the experiments depending on their instructional goals. In the unit 'air and how things…

The Development of Acoustic Experiments for Off-Campus Teaching and Learning

ERIC Educational Resources Information Center

Wild, Graham; Swan, Geoff

2011-01-01

In this article, we show the implementation of a computer-based digital storage oscilloscope (DSO) and function generator (FG) using the computer's soundcard for off-campus acoustic experiments. The microphone input is used for the DSO, and a speaker jack is used as the FG. In an effort to reduce the cost of implementing the experiment, we examine…

BelleII@home: Integrate volunteer computing resources into DIRAC in a secure way

NASA Astrophysics Data System (ADS)

Wu, Wenjing; Hara, Takanori; Miyake, Hideki; Ueda, Ikuo; Kan, Wenxiao; Urquijo, Phillip

2017-10-01

The exploitation of volunteer computing resources has become a popular practice in the HEP computing community as the huge amount of potential computing power it provides. In the recent HEP experiments, the grid middleware has been used to organize the services and the resources, however it relies heavily on the X.509 authentication, which is contradictory to the untrusted feature of volunteer computing resources, therefore one big challenge to utilize the volunteer computing resources is how to integrate them into the grid middleware in a secure way. The DIRAC interware which is commonly used as the major component of the grid computing infrastructure for several HEP experiments proposes an even bigger challenge to this paradox as its pilot is more closely coupled with operations requiring the X.509 authentication compared to the implementations of pilot in its peer grid interware. The Belle II experiment is a B-factory experiment at KEK, and it uses DIRAC for its distributed computing. In the project of BelleII@home, in order to integrate the volunteer computing resources into the Belle II distributed computing platform in a secure way, we adopted a new approach which detaches the payload running from the Belle II DIRAC pilot which is a customized pilot pulling and processing jobs from the Belle II distributed computing platform, so that the payload can run on volunteer computers without requiring any X.509 authentication. In this approach we developed a gateway service running on a trusted server which handles all the operations requiring the X.509 authentication. So far, we have developed and deployed the prototype of BelleII@home, and tested its full workflow which proves the feasibility of this approach. This approach can also be applied on HPC systems whose work nodes do not have outbound connectivity to interact with the DIRAC system in general.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stoller, Roger E; Nordlund, Kai; Melerba, L

The processes that give rise to changes in the microstructure and the physical and mechanical properties of materials exposed to energetic particles are initiated by essentially elastic collisions between atoms in what has been called an atomic displacement cascade. The formation and evolution of this primary radiation damage mechanism are described to provide an overview of how stable defects are formed by displacement cascades, as well as the nature and morphology of the defects themselves. The impact of the primary variables cascade energy and irradiation temperature are discussed, along with a range of secondary factors that can influence damage formation.Radiation-inducedmore » changes in microstructure and mechanical properties in structural materials are the result of a complex set of physical processes initiated by the collision between an energetic particle (neutron or ion) and an atom in the lattice. This primary damage event is called an atomic displacement cascade. The simplest description of a displacement cascade is to view it as a series of many billiard-ball-like elastic collisions among the atoms in the material. This chapter describes the formation and evolution of this primary radiation damage mechanism to provide an overview of how stable defects are formed by displacement cascades, as well as the nature and morphology of the defects themselves. The impact of the relevant variables such as cascade energy and irradiation temperature is discussed, and defect formation in different materials is compared.« less

Occupant perception of indoor air and comfort in four hospitality environments.

PubMed

Moschandreas, D J; Chu, P

2002-01-01

This article reports on a survey of customer and staff perceptions of indoor air quality at two restaurants, a billiard hall, and a casino. The survey was conducted at each environment for 8 days: 2 weekend days on 2 consecutive weekends and 4 weekdays. Before and during the survey, each hospitality environment satisfied ventilation requirements set in ASHRAE Standard 62-1999, Ventilation for Acceptable Indoor Air. An objective of this study was to test the hypothesis: If a hospitality environment satisfies ASHRAE ventilation requirements, then the indoor air is acceptable, that is, fewer than 20% of the exposed occupants perceive the environment as unacceptable. A second objective was to develop a multiple regression model that predicts the dependent variable, the environment is acceptable, as a function of a number of independent perception variables. Occupant perception of environmental, comfort, and physical variables was measured using a questionnaire. This instrument was designed to be efficient and unobtrusive; subjects could complete it within 3 min. Significant differences of occupant environment perception were identified among customers and staff. The dependent variable, the environment is acceptable, is affected by temperature, occupant density, and occupant smoking status, odor perception, health conditions, sensitivity to chemicals, and enjoyment of activities. Depending on the hospitality environment, variation of independent variables explains as much as 77% of the variation of the dependent variable.

Computers in the General Physics Laboratory.

ERIC Educational Resources Information Center

Preston, Daryl W.; Good, R. H.

1996-01-01

Provides ideas and outcomes for nine computer laboratory experiments using a commercial eight-bit analog to digital (ADC) interface. Experiments cover statistics; rotation; harmonic motion; voltage, current, and resistance; ADC conversions; temperature measurement; single slit diffraction; and radioactive decay. Includes necessary schematics. (MVL)

Computer Learning for Young Children.

ERIC Educational Resources Information Center

Choy, Anita Y.

1995-01-01

Computer activities that combine education and entertainment make learning easy and fun for preschoolers. Computers encourage social skills, language and literacy skills, cognitive development, problem solving, and eye-hand coordination. The paper describes one teacher's experiences setting up a computer center and using computers with…

A parallel Jacobson-Oksman optimization algorithm. [parallel processing (computers)

NASA Technical Reports Server (NTRS)

Straeter, T. A.; Markos, A. T.

1975-01-01

A gradient-dependent optimization technique which exploits the vector-streaming or parallel-computing capabilities of some modern computers is presented. The algorithm, derived by assuming that the function to be minimized is homogeneous, is a modification of the Jacobson-Oksman serial minimization method. In addition to describing the algorithm, conditions insuring the convergence of the iterates of the algorithm and the results of numerical experiments on a group of sample test functions are presented. The results of these experiments indicate that this algorithm will solve optimization problems in less computing time than conventional serial methods on machines having vector-streaming or parallel-computing capabilities.

Computer Assisted Thermography And Its Application In Ovulation Detection

NASA Astrophysics Data System (ADS)

Rao, K. H.; Shah, A. V.

1984-08-01

Hardware and software of a computer-assisted image analyzing system used for infrared images in medical applications are discussed. The application of computer-assisted thermography (CAT) as a complementary diagnostic tool in centralized diagnostic management is proposed. The authors adopted 'Computer Assisted Thermography' to study physiological changes in the breasts related to the hormones characterizing the menstrual cycle of a woman. Based on clinical experi-ments followed by thermal image analysis, they suggest that 'differential skin temperature (DST)1 be measured to detect the fertility interval in the menstrual cycle of a woman.

Examining the Effects of Learning Styles, Epistemic Beliefs and the Computational Experiment Methodology on Learners' Performance Using the Easy Java Simulator Tool in STEM Disciplines

ERIC Educational Resources Information Center

Psycharis, Sarantos; Botsari, Evanthia; Chatzarakis, George

2014-01-01

Learning styles are increasingly being integrated into computational-enhanced earning environments and a great deal of recent research work is taking place in this area. The purpose of this study was to examine the impact of the computational experiment approach, learning styles, epistemic beliefs, and engagement with the inquiry process on the…

Computers in mathematics: teacher-inservice training at a distance

NASA Astrophysics Data System (ADS)

Friedman, Edward A.; Jurkat, M. P.

1993-01-01

While research and experience show many advantages for incorporation of computer technology into secondary school mathematics instruction, less than 5 percent of the nation's teachers are actively using computers in their classrooms. This is the case even though mathematics teachers in grades 7 - 12 are often familiar with computer technology and have computers available to them in their schools. The implementation bottleneck is in-service teacher training and there are few models of effective implementation available for teachers to emulate. Stevens Institute of Technology has been active since 1988 in research and development efforts to incorporate computers into classroom use. We have found that teachers need to see examples of classroom experience with hardware and software and they need to have assistance as they experiment with applications of software and the development of lesson plans. High-band width technology can greatly facilitate teacher training in this area through transmission of video documentaries, software discussions, teleconferencing, peer interactions, classroom observations, etc. We discuss the experience that Stevens has had with face-to-face teacher training as well as with satellite-based teleconferencing using one-way video and two- way audio. Included are reviews of analyses of this project by researchers from Educational Testing Service, Princeton University, and Bank Street School of Education.

Integration of Russian Tier-1 Grid Center with High Performance Computers at NRC-KI for LHC experiments and beyond HENP

NASA Astrophysics Data System (ADS)

Belyaev, A.; Berezhnaya, A.; Betev, L.; Buncic, P.; De, K.; Drizhuk, D.; Klimentov, A.; Lazin, Y.; Lyalin, I.; Mashinistov, R.; Novikov, A.; Oleynik, D.; Polyakov, A.; Poyda, A.; Ryabinkin, E.; Teslyuk, A.; Tkachenko, I.; Yasnopolskiy, L.

2015-12-01

The LHC experiments are preparing for the precision measurements and further discoveries that will be made possible by higher LHC energies from April 2015 (LHC Run2). The need for simulation, data processing and analysis would overwhelm the expected capacity of grid infrastructure computing facilities deployed by the Worldwide LHC Computing Grid (WLCG). To meet this challenge the integration of the opportunistic resources into LHC computing model is highly important. The Tier-1 facility at Kurchatov Institute (NRC-KI) in Moscow is a part of WLCG and it will process, simulate and store up to 10% of total data obtained from ALICE, ATLAS and LHCb experiments. In addition Kurchatov Institute has supercomputers with peak performance 0.12 PFLOPS. The delegation of even a fraction of supercomputing resources to the LHC Computing will notably increase total capacity. In 2014 the development a portal combining a Tier-1 and a supercomputer in Kurchatov Institute was started to provide common interfaces and storage. The portal will be used not only for HENP experiments, but also by other data- and compute-intensive sciences like biology with genome sequencing analysis; astrophysics with cosmic rays analysis, antimatter and dark matter search, etc.

Analyses of requirements for computer control and data processing experiment subsystems. Volume 1: ATM experiment S-056 image data processing system techniques development

NASA Technical Reports Server (NTRS)

1972-01-01

The solar imaging X-ray telescope experiment (designated the S-056 experiment) is described. It will photograph the sun in the far ultraviolet or soft X-ray region. Because of the imaging characteristics of this telescope and the necessity of using special techniques for capturing images on film at these wave lengths, methods were developed for computer processing of the photographs. The problems of image restoration were addressed to develop and test digital computer techniques for applying a deconvolution process to restore overall S-056 image quality. Additional techniques for reducing or eliminating the effects of noise and nonlinearity in S-056 photographs were developed.

Hispanic women overcoming deterrents to computer science: A phenomenological study

NASA Astrophysics Data System (ADS)

Herling, Lourdes

The products of computer science are important to all aspects of society and are tools in the solution of the world's problems. It is, therefore, troubling that the United States faces a shortage in qualified graduates in computer science. The number of women and minorities in computer science is significantly lower than the percentage of the U.S. population which they represent. The overall enrollment in computer science programs has continued to decline with the enrollment of women declining at a higher rate than that of men. This study addressed three aspects of underrepresentation about which there has been little previous research: addressing computing disciplines specifically rather than embedding them within the STEM disciplines, what attracts women and minorities to computer science, and addressing the issues of race/ethnicity and gender in conjunction rather than in isolation. Since women of underrepresented ethnicities are more severely underrepresented than women in general, it is important to consider whether race and ethnicity play a role in addition to gender as has been suggested by previous research. Therefore, this study examined what attracted Hispanic women to computer science specifically. The study determines whether being subjected to multiple marginalizations---female and Hispanic---played a role in the experiences of Hispanic women currently in computer science. The study found five emergent themes within the experiences of Hispanic women in computer science. Encouragement and role models strongly influenced not only the participants' choice to major in the field, but to persist as well. Most of the participants experienced a negative atmosphere and feelings of not fitting in while in college and industry. The interdisciplinary nature of computer science was the most common aspect that attracted the participants to computer science. The aptitudes participants commonly believed are needed for success in computer science are the Twenty-First Century skills problem solving, creativity, and critical thinking. While not all the participants had experience with computers or programming prior to attending college, experience played a role in the self-confidence of those who did.

Engineering and Computing Portal to Solve Environmental Problems

NASA Astrophysics Data System (ADS)

Gudov, A. M.; Zavozkin, S. Y.; Sotnikov, I. Y.

2018-01-01

This paper describes architecture and services of the Engineering and Computing Portal, which is considered to be a complex solution that provides access to high-performance computing resources, enables to carry out computational experiments, teach parallel technologies and solve computing tasks, including technogenic safety ones.

Portable computing - A fielded interactive scientific application in a small off-the-shelf package

NASA Technical Reports Server (NTRS)

Groleau, Nicolas; Hazelton, Lyman; Frainier, Rich; Compton, Michael; Colombano, Silvano; Szolovits, Peter

1993-01-01

Experience with the design and implementation of a portable computing system for STS crew-conducted science is discussed. Principal-Investigator-in-a-Box (PI) will help the SLS-2 astronauts perform vestibular (human orientation system) experiments in flight. PI is an interactive system that provides data acquisition and analysis, experiment step rescheduling, and various other forms of reasoning to astronaut users. The hardware architecture of PI consists of a computer and an analog interface box. 'Off-the-shelf' equipment is employed in the system wherever possible in an effort to use widely available tools and then to add custom functionality and application codes to them. Other projects which can help prospective teams to learn more about portable computing in space are also discussed.

Volunteer Computing Experience with ATLAS@Home

NASA Astrophysics Data System (ADS)

Adam-Bourdarios, C.; Bianchi, R.; Cameron, D.; Filipčič, A.; Isacchini, G.; Lançon, E.; Wu, W.; ATLAS Collaboration

2017-10-01

ATLAS@Home is a volunteer computing project which allows the public to contribute to computing for the ATLAS experiment through their home or office computers. The project has grown continuously since its creation in mid-2014 and now counts almost 100,000 volunteers. The combined volunteers’ resources make up a sizeable fraction of overall resources for ATLAS simulation. This paper takes stock of the experience gained so far and describes the next steps in the evolution of the project. These improvements include running natively on Linux to ease the deployment on for example university clusters, using multiple cores inside one task to reduce the memory requirements and running different types of workload such as event generation. In addition to technical details the success of ATLAS@Home as an outreach tool is evaluated.

View of MISSE-8 taken during a session of EVA

NASA Image and Video Library

2011-07-12

ISS028-E-016107 (12 July 2011) --- This medium close-up image, recorded during a July 12 spacewalk, shows the Materials on International Space Station Experiment - 8 (MISSE-8). The experiment package is a test bed for materials and computing elements attached to the outside of the orbiting complex. These materials and computing elements are being evaluated for the effects of atomic oxygen, ultraviolet, direct sunlight, radiation, and extremes of heat and cold. This experiment allows the development and testing of new materials and computing elements that can better withstand the rigors of space environments. Results will provide a better understanding of the durability of various materials and computing elements when they are exposed to the space environment, with applications in the design of future spacecraft.

Model-Invariant Hybrid Computations of Separated Flows for RCA Standard Test Cases

NASA Technical Reports Server (NTRS)

Woodruff, Stephen

2016-01-01

NASA's Revolutionary Computational Aerosciences (RCA) subproject has identified several smooth-body separated flows as standard test cases to emphasize the challenge these flows present for computational methods and their importance to the aerospace community. Results of computations of two of these test cases, the NASA hump and the FAITH experiment, are presented. The computations were performed with the model-invariant hybrid LES-RANS formulation, implemented in the NASA code VULCAN-CFD. The model- invariant formulation employs gradual LES-RANS transitions and compensation for model variation to provide more accurate and efficient hybrid computations. Comparisons revealed that the LES-RANS transitions employed in these computations were sufficiently gradual that the compensating terms were unnecessary. Agreement with experiment was achieved only after reducing the turbulent viscosity to mitigate the effect of numerical dissipation. The stream-wise evolution of peak Reynolds shear stress was employed as a measure of turbulence dynamics in separated flows useful for evaluating computations.

Comparison of two computer programs by predicting turbulent mixing of helium in a ducted supersonic airstream

NASA Technical Reports Server (NTRS)

Pan, Y. S.; Drummond, J. P.; Mcclinton, C. R.

1978-01-01

Two parabolic flow computer programs, SHIP (a finite-difference program) and COMOC (a finite-element program), are used for predicting three-dimensional turbulent reacting flow fields in supersonic combustors. The theoretical foundation of the two computer programs are described, and then the programs are applied to a three-dimensional turbulent mixing experiment. The cold (nonreacting) flow experiment was performed to study the mixing of helium jets with a supersonic airstream in a rectangular duct. Surveys of the flow field at an upstream were used as the initial data by programs; surveys at a downstream station provided comparison to assess program accuracy. Both computer programs predicted the experimental results and data trends reasonably well. However, the comparison between the computations from the two programs indicated that SHIP was more accurate in computation and more efficient in both computer storage and computing time than COMOC.

Euler and Potential Experiment/CFD Correlations for a Transport and Two Delta-Wing Configurations

NASA Technical Reports Server (NTRS)

Hicks, R. M.; Cliff, S. E.; Melton, J. E.; Langhi, R. G.; Goodsell, A. M.; Robertson, D. D.; Moyer, S. A.

1990-01-01

A selection of successes and failures of Computational Fluid Dynamics (CFD) is discussed. Experiment/CFD correlations involving full potential and Euler computations of the aerodynamic characteristics of four commercial transport wings and two low aspect ratio, delta wing configurations are shown. The examples consist of experiment/CFD comparisons for aerodynamic forces, moments, and pressures. Navier-Stokes equations are not considered.

A qualitative study of technophobic students' reactions to a technology-rich college science course

NASA Astrophysics Data System (ADS)

Guttschow, Gena Lee

The use of technology in education has grown rapidly in the last 20 years. In fact, many of today's college students have had some sort of computer in their elementary school classrooms. One might think that this consistent exposure to computers would foster positive attitudes about computers but this is not always the case. Currently, a substantial number of college students dislike interacting with technology. People who dislike interacting with technology are often referred to as "technophobic". Technophobic people have negative thoughts and feelings about technology and they often have a desire to avoid interaction with technology. Technophobic students' negative feelings about technology have the potential to interfere with their learning when technology is utilized as a tool for instruction of school subjects. As computer use becomes prevalent and in many instances mandatory in education, the issue of technophobia increasingly needs to be understood and addressed. This is a qualitative study designed with the intent of gaining an understanding the experiences of technophobic students who are required to use technology to learn science in a college class. Six developmental college students enrolled in a computer based anatomy and physiology class were chosen to participate in the study based on their high technophobia scores. They were interviewed three times during the quarter and videotaped once. The interview data were transcribed, coded, and analyzed. The analysis resulted in six case studies describing each participant's experience and 11 themes representing overlapping areas in the participants' worlds of experience. A discussion of the themes, the meaning they hold for me as a science educator and how they relate to the existing literature, is presented. The participants' descriptions of their experiences showed that the technophobic students did use the computers and learned skills when they had to in order to complete assignments. It was also revealed that the technophobic participants' negative attitudes did not improve after learning computer skills. Lastly, based on the participants' experiences it seems important to start a class with step-by step computer training, teaching foundational computer skills, and slowly progress towards autonomous computer exploration.

Study of Wind Effects on Unique Buildings

NASA Astrophysics Data System (ADS)

Olenkov, V.; Puzyrev, P.

2017-11-01

The article deals with a numerical simulation of wind effects on the building of the Church of the Intercession of the Holy Virgin in the village Bulzi of the Chelyabinsk region. We presented a calculation algorithm and obtained pressure fields, velocity fields and the fields of kinetic energy of a wind stream, as well as streamlines. Computational fluid dynamic (CFD) evolved three decades ago at the interfaces of calculus mathematics and theoretical hydromechanics and has become a separate branch of science the subject of which is a numerical simulation of different fluid and gas flows as well as the solution of arising problems with the help of methods that involve computer systems. This scientific field which is of a great practical value is intensively developing. The increase in CFD-calculations is caused by the improvement of computer technologies, creation of multipurpose easy-to-use CFD-packagers that are available to a wide group of researchers and cope with various tasks. Such programs are not only competitive in comparison with physical experiments but sometimes they provide the only opportunity to answer the research questions. The following advantages of computer simulation can be pointed out: a) Reduction in time spent on design and development of a model in comparison with a real experiment (variation of boundary conditions). b) Numerical experiment allows for the simulation of conditions that are not reproducible with environmental tests (use of ideal gas as environment). c) Use of computational gas dynamics methods provides a researcher with a complete and ample information that is necessary to fully describe different processes of the experiment. d) Economic efficiency of computer calculations is more attractive than an experiment. e) Possibility to modify a computational model which ensures efficient timing (change of the sizes of wall layer cells in accordance with the chosen turbulence model).

The Gender Factor in Computer Anxiety and Interest among Some Australian High School Students.

ERIC Educational Resources Information Center

Okebukola, Peter Akinsola

1993-01-01

Western Australia eleventh graders (142 boys, 139 girls) were compared on such variables as computers at home, computer classes, experience with computers, and socioeconomic status. Girls had higher anxiety levels, boys higher computer interest. Possible causes included social beliefs about computer use, teacher sex bias, and software (games) more…

Computer-Game Construction: A Gender-Neutral Attractor to Computing Science

ERIC Educational Resources Information Center

Carbonaro, Mike; Szafron, Duane; Cutumisu, Maria; Schaeffer, Jonathan

2010-01-01

Enrollment in Computing Science university programs is at a dangerously low level. A major reason for this is the general lack of interest in Computing Science by females. In this paper, we discuss our experience with using a computer game construction environment as a vehicle to encourage female participation in Computing Science. Experiments…

Mobile Computing for Aerospace Applications

NASA Technical Reports Server (NTRS)

Alena, Richard; Swietek, Gregory E. (Technical Monitor)

1994-01-01

The use of commercial computer technology in specific aerospace mission applications can reduce the cost and project cycle time required for the development of special-purpose computer systems. Additionally, the pace of technological innovation in the commercial market has made new computer capabilities available for demonstrations and flight tests. Three areas of research and development being explored by the Portable Computer Technology Project at NASA Ames Research Center are the application of commercial client/server network computing solutions to crew support and payload operations, the analysis of requirements for portable computing devices, and testing of wireless data communication links as extensions to the wired network. This paper will present computer architectural solutions to portable workstation design including the use of standard interfaces, advanced flat-panel displays and network configurations incorporating both wired and wireless transmission media. It will describe the design tradeoffs used in selecting high-performance processors and memories, interfaces for communication and peripheral control, and high resolution displays. The packaging issues for safe and reliable operation aboard spacecraft and aircraft are presented. The current status of wireless data links for portable computers is discussed from a system design perspective. An end-to-end data flow model for payload science operations from the experiment flight rack to the principal investigator is analyzed using capabilities provided by the new generation of computer products. A future flight experiment on-board the Russian MIR space station will be described in detail including system configuration and function, the characteristics of the spacecraft operating environment, the flight qualification measures needed for safety review, and the specifications of the computing devices to be used in the experiment. The software architecture chosen shall be presented. An analysis of the performance characteristics of wireless data links in the spacecraft environment will be discussed. Network performance and operation will be modeled and preliminary test results presented. A crew support application will be demonstrated in conjunction with the network metrics experiment.

The Effects of Video Game Experience on Computer-Based Air Traffic Controller Specialist, Air Traffic Scenario Test Scores.

DTIC Science & Technology

1997-02-01

application with a strong resemblance to a video game , concern has been raised that prior video game experience might have a moderating effect on scores. Much...such as spatial ability. The effects of computer or video game experience on work sample scores have not been systematically investigated. The purpose...of this study was to evaluate the incremental validity of prior video game experience over that of general aptitude as a predictor of work sample test

An Implicit Upwind Algorithm for Computing Turbulent Flows on Unstructured Grids

NASA Technical Reports Server (NTRS)

Anerson, W. Kyle; Bonhaus, Daryl L.

1994-01-01

An implicit, Navier-Stokes solution algorithm is presented for the computation of turbulent flow on unstructured grids. The inviscid fluxes are computed using an upwind algorithm and the solution is advanced in time using a backward-Euler time-stepping scheme. At each time step, the linear system of equations is approximately solved with a point-implicit relaxation scheme. This methodology provides a viable and robust algorithm for computing turbulent flows on unstructured meshes. Results are shown for subsonic flow over a NACA 0012 airfoil and for transonic flow over a RAE 2822 airfoil exhibiting a strong upper-surface shock. In addition, results are shown for 3 element and 4 element airfoil configurations. For the calculations, two one equation turbulence models are utilized. For the NACA 0012 airfoil, a pressure distribution and force data are compared with other computational results as well as with experiment. Comparisons of computed pressure distributions and velocity profiles with experimental data are shown for the RAE airfoil and for the 3 element configuration. For the 4 element case, comparisons of surface pressure distributions with experiment are made. In general, the agreement between the computations and the experiment is good.

Hand-held computer operating system program for collection of resident experience data.

PubMed

Malan, T K; Haffner, W H; Armstrong, A Y; Satin, A J

2000-11-01

To describe a system for recording resident experience involving hand-held computers with the Palm Operating System (3 Com, Inc., Santa Clara, CA). Hand-held personal computers (PCs) are popular, easy to use, inexpensive, portable, and can share data among other operating systems. Residents in our program carry individual hand-held database computers to record Residency Review Committee (RRC) reportable patient encounters. Each resident's data is transferred to a single central relational database compatible with Microsoft Access (Microsoft Corporation, Redmond, WA). Patient data entry and subsequent transfer to a central database is accomplished with commercially available software that requires minimal computer expertise to implement and maintain. The central database can then be used for statistical analysis or to create required RRC resident experience reports. As a result, the data collection and transfer process takes less time for residents and program director alike, than paper-based or central computer-based systems. The system of collecting resident encounter data using hand-held computers with the Palm Operating System is easy to use, relatively inexpensive, accurate, and secure. The user-friendly system provides prompt, complete, and accurate data, enhancing the education of residents while facilitating the job of the program director.

Computer Based Simulation of Laboratory Experiments.

ERIC Educational Resources Information Center

Edward, Norrie S.

1997-01-01

Examines computer based simulations of practical laboratory experiments in engineering. Discusses the aims and achievements of lab work (cognitive, process, psychomotor, and affective); types of simulations (model building and behavioral); and the strengths and weaknesses of simulations. Describes the development of a centrifugal pump simulation,…

Attitudes toward Computer Instruction.

ERIC Educational Resources Information Center

German, Kenneth E.

1988-01-01

Describes the use of the Brown scale and reports the results of its use in an experiment. Describes the instrument and details the experiment. Concludes that the Brown scale is a valid and reliable instrument for measuring attitude toward computer instruction. A copy of the instrument is included. (CW)

Computational Science: A Research Methodology for the 21st Century

NASA Astrophysics Data System (ADS)

Orbach, Raymond L.

2004-03-01

Computational simulation - a means of scientific discovery that employs computer systems to simulate a physical system according to laws derived from theory and experiment - has attained peer status with theory and experiment. Important advances in basic science are accomplished by a new "sociology" for ultrascale scientific computing capability (USSCC), a fusion of sustained advances in scientific models, mathematical algorithms, computer architecture, and scientific software engineering. Expansion of current capabilities by factors of 100 - 1000 open up new vistas for scientific discovery: long term climatic variability and change, macroscopic material design from correlated behavior at the nanoscale, design and optimization of magnetic confinement fusion reactors, strong interactions on a computational lattice through quantum chromodynamics, and stellar explosions and element production. The "virtual prototype," made possible by this expansion, can markedly reduce time-to-market for industrial applications such as jet engines and safer, more fuel efficient cleaner cars. In order to develop USSCC, the National Energy Research Scientific Computing Center (NERSC) announced the competition "Innovative and Novel Computational Impact on Theory and Experiment" (INCITE), with no requirement for current DOE sponsorship. Fifty nine proposals for grand challenge scientific problems were submitted for a small number of awards. The successful grants, and their preliminary progress, will be described.

A prisoner's dilemma experiment on cooperation with people and human-like computers.

PubMed

Kiesler, S; Sproull, L; Waters, K

1996-01-01

The authors investigated basic properties of social exchange and interaction with technology in an experiment on cooperation with a human-like computer partner or a real human partner. Talking with a computer partner may trigger social identity feelings or commitment norms. Participants played a prisoner's dilemma game with a confederate or a computer partner. Discussion, inducements to make promises, and partner cooperation varied across trials. On Trial 1, after discussion, most participants proposed cooperation. They kept their promises as much with a text-only computer as with a person, but less with a more human-like computer. Cooperation dropped sharply when any partner avoided discussion. The strong impact of discussion fits a social contract explanation of cooperation following discussion. Participants broke their promises to a computer more than to a person, however, indicating that people make heterogeneous commitments.

The impact of supercomputers on experimentation: A view from a national laboratory

NASA Technical Reports Server (NTRS)

Peterson, V. L.; Arnold, J. O.

1985-01-01

The relative roles of large scale scientific computers and physical experiments in several science and engineering disciplines are discussed. Increasing dependence on computers is shown to be motivated both by the rapid growth in computer speed and memory, which permits accurate numerical simulation of complex physical phenomena, and by the rapid reduction in the cost of performing a calculation, which makes computation an increasingly attractive complement to experimentation. Computer speed and memory requirements are presented for selected areas of such disciplines as fluid dynamics, aerodynamics, aerothermodynamics, chemistry, atmospheric sciences, astronomy, and astrophysics, together with some examples of the complementary nature of computation and experiment. Finally, the impact of the emerging role of computers in the technical disciplines is discussed in terms of both the requirements for experimentation and the attainment of previously inaccessible information on physical processes.

Evaluating Computer Technology Integration in a Centralized School System

ERIC Educational Resources Information Center

Eteokleous, N.

2008-01-01

The study evaluated the current situation in Cyprus elementary classrooms regarding computer technology integration in an attempt to identify ways of expanding teachers' and students' experiences with computer technology. It examined how Cypriot elementary teachers use computers, and the factors that influence computer integration in their…

Parallel computing in genomic research: advances and applications

PubMed Central

Ocaña, Kary; de Oliveira, Daniel

2015-01-01

Today’s genomic experiments have to process the so-called “biological big data” that is now reaching the size of Terabytes and Petabytes. To process this huge amount of data, scientists may require weeks or months if they use their own workstations. Parallelism techniques and high-performance computing (HPC) environments can be applied for reducing the total processing time and to ease the management, treatment, and analyses of this data. However, running bioinformatics experiments in HPC environments such as clouds, grids, clusters, and graphics processing unit requires the expertise from scientists to integrate computational, biological, and mathematical techniques and technologies. Several solutions have already been proposed to allow scientists for processing their genomic experiments using HPC capabilities and parallelism techniques. This article brings a systematic review of literature that surveys the most recently published research involving genomics and parallel computing. Our objective is to gather the main characteristics, benefits, and challenges that can be considered by scientists when running their genomic experiments to benefit from parallelism techniques and HPC capabilities. PMID:26604801

Parallel computing in genomic research: advances and applications.

PubMed

Ocaña, Kary; de Oliveira, Daniel

2015-01-01

Today's genomic experiments have to process the so-called "biological big data" that is now reaching the size of Terabytes and Petabytes. To process this huge amount of data, scientists may require weeks or months if they use their own workstations. Parallelism techniques and high-performance computing (HPC) environments can be applied for reducing the total processing time and to ease the management, treatment, and analyses of this data. However, running bioinformatics experiments in HPC environments such as clouds, grids, clusters, and graphics processing unit requires the expertise from scientists to integrate computational, biological, and mathematical techniques and technologies. Several solutions have already been proposed to allow scientists for processing their genomic experiments using HPC capabilities and parallelism techniques. This article brings a systematic review of literature that surveys the most recently published research involving genomics and parallel computing. Our objective is to gather the main characteristics, benefits, and challenges that can be considered by scientists when running their genomic experiments to benefit from parallelism techniques and HPC capabilities.

Quantum Chaos

NASA Astrophysics Data System (ADS)

Casati, Giulio; Chirikov, Boris

2006-11-01

Preface; Acknowledgments; Introduction: 1. The legacy of chaos in quantum mechanics G. Casati and B. V. Chirikov; Part I. Classical Chaos and Quantum Localization: 2. Stochastic behaviour of a quantum pendulum under a periodic perturbation G. Casati, B. V. Chirikov, F. M. Izrailev and J. Ford; 3. Quantum dynamics of a nonintegrable system D. R. Grempel, R. E. Prange and S. E. Fishman; 4. Excitation of molecular rotation by periodic microwave pulses. A testing ground for Anderson localization R. Blümel, S. Fishman and U. Smilansky; 5. Localization of diffusive excitation in multi-level systems D. K. Shepelyansky; 6. Classical and quantum chaos for a kicked top F. Haake, M. Kus and R. Scharf; 7. Self-similarity in quantum dynamics L. E. Reichl and L. Haoming; 8. Time irreversibility of classically chaotic quantum dynamics K. Ikeda; 9. Effect of noise on time-dependent quantum chaos E. Ott, T. M. Antonsen Jr and J. D. Hanson; 10. Dynamical localization, dissipation and noise R. F. Graham; 11. Maximum entropy models and quantum transmission in disordered systems J.-L. Pichard and M. Sanquer; 12. Solid state 'atoms' in intense oscillating fields M. S. Sherwin; Part II. Atoms in Strong Fields: 13. Localization of classically chaotic diffusion for hydrogen atoms in microwave fields J. E. Bayfield, G. Casati, I. Guarneri and D. W. Sokol; 14. Inhibition of quantum transport due to 'scars' of unstable periodic orbits R. V. Jensen, M. M. Sanders, M. Saraceno and B. Sundaram; 15. Rubidium Rydberg atoms in strong fields G. Benson, G. Raithel and H. Walther; 16. Diamagnetic Rydberg atom: confrontation of calculated and observed spectra C.-H. Iu, G. R. Welch, M. M. Kash, D. Kleppner, D. Delande and J. C. Gay; 17. Semiclassical approximation for the quantum states of a hydrogen atom in a magnetic field near the ionization limit M. Y. Kuchiev and O. P. Sushkov; 18. The semiclassical helium atom D. Wintgen, K. Richter and G. Tanner; 19. Stretched helium: a model for quantum chaos in two-electron atoms R. Blümel and W. P. Reinhardt; Part III. Semiclassical Approximations: 20. Semiclassical theory of spectral rigidity M. V. Berry; 21. Semiclassical structure of trace formulas R. G. Littlejohn; 22. h-Expansion for quantum trace formulas P. Gaspard; 23. Pinball scattering B. Eckhardt, G. Russberg, P. Cvitanovic, P. E. Rosenqvist and P. Scherer; 24. Logarithm breaking time in quantum chaos G. P. Berman and G. M. Zaslavsky; 25. Semiclassical propagation: how long can it last? M. A. Sepulveda, S. Tomsovic and E. J. Heller; 26. The quantized Baker's transformation N. L. Balazs and A. Voros; 27. Classical structures in the quantized baker transformation M. Saraceno; 28. Quantum nodal points as fingerprints of classical chaos P. Leboeuf and A. Voros; 29. Chaology of action billiards A. M. Ozorio de Almeida and M. A. M. de Aguiar; Part IV. Level Statistics and Random Matrix Theory: 30. Characterization of chaotic quantum spectra and universality of level fluctuation laws O. Bohigas, M. J. Giannono, and C. Schmit; 31. Quantum chaos, localization and band random matrices F. M. Izrailev; 32. Structural invariance in channel space: a step toward understanding chaotic scattering in quantum mechanics T. H. Seligman; 33. Spectral properties of a Fermi accelerating disk R. Badrinarayanan and J. J. José; 34. Spectral properties of systems with dynamical localization T. Dittrich and U. Smilansky; 35. Unbound quantum diffusion and fractal spectra T. Geisel, R. Ketzmerick and G. Petschel; 36. Microwave studies in irregularly shaped billiards H.-J. Stöckmann, J. Stein and M. Kollman; Index.

Quantum Chaos

NASA Astrophysics Data System (ADS)

Casati, Giulio; Chirikov, Boris

1995-04-01

Preface; Acknowledgments; Introduction: 1. The legacy of chaos in quantum mechanics G. Casati and B. V. Chirikov; Part I. Classical Chaos and Quantum Localization: 2. Stochastic behaviour of a quantum pendulum under a periodic perturbation G. Casati, B. V. Chirikov, F. M. Izrailev and J. Ford; 3. Quantum dynamics of a nonintegrable system D. R. Grempel, R. E. Prange and S. E. Fishman; 4. Excitation of molecular rotation by periodic microwave pulses. A testing ground for Anderson localization R. Blümel, S. Fishman and U. Smilansky; 5. Localization of diffusive excitation in multi-level systems D. K. Shepelyansky; 6. Classical and quantum chaos for a kicked top F. Haake, M. Kus and R. Scharf; 7. Self-similarity in quantum dynamics L. E. Reichl and L. Haoming; 8. Time irreversibility of classically chaotic quantum dynamics K. Ikeda; 9. Effect of noise on time-dependent quantum chaos E. Ott, T. M. Antonsen Jr and J. D. Hanson; 10. Dynamical localization, dissipation and noise R. F. Graham; 11. Maximum entropy models and quantum transmission in disordered systems J.-L. Pichard and M. Sanquer; 12. Solid state 'atoms' in intense oscillating fields M. S. Sherwin; Part II. Atoms in Strong Fields: 13. Localization of classically chaotic diffusion for hydrogen atoms in microwave fields J. E. Bayfield, G. Casati, I. Guarneri and D. W. Sokol; 14. Inhibition of quantum transport due to 'scars' of unstable periodic orbits R. V. Jensen, M. M. Sanders, M. Saraceno and B. Sundaram; 15. Rubidium Rydberg atoms in strong fields G. Benson, G. Raithel and H. Walther; 16. Diamagnetic Rydberg atom: confrontation of calculated and observed spectra C.-H. Iu, G. R. Welch, M. M. Kash, D. Kleppner, D. Delande and J. C. Gay; 17. Semiclassical approximation for the quantum states of a hydrogen atom in a magnetic field near the ionization limit M. Y. Kuchiev and O. P. Sushkov; 18. The semiclassical helium atom D. Wintgen, K. Richter and G. Tanner; 19. Stretched helium: a model for quantum chaos in two-electron atoms R. Blümel and W. P. Reinhardt; Part III. Semiclassical Approximations: 20. Semiclassical theory of spectral rigidity M. V. Berry; 21. Semiclassical structure of trace formulas R. G. Littlejohn; 22. h-Expansion for quantum trace formulas P. Gaspard; 23. Pinball scattering B. Eckhardt, G. Russberg, P. Cvitanovic, P. E. Rosenqvist and P. Scherer; 24. Logarithm breaking time in quantum chaos G. P. Berman and G. M. Zaslavsky; 25. Semiclassical propagation: how long can it last? M. A. Sepulveda, S. Tomsovic and E. J. Heller; 26. The quantized Baker's transformation N. L. Balazs and A. Voros; 27. Classical structures in the quantized baker transformation M. Saraceno; 28. Quantum nodal points as fingerprints of classical chaos P. Leboeuf and A. Voros; 29. Chaology of action billiards A. M. Ozorio de Almeida and M. A. M. de Aguiar; Part IV. Level Statistics and Random Matrix Theory: 30. Characterization of chaotic quantum spectra and universality of level fluctuation laws O. Bohigas, M. J. Giannono, and C. Schmit; 31. Quantum chaos, localization and band random matrices F. M. Izrailev; 32. Structural invariance in channel space: a step toward understanding chaotic scattering in quantum mechanics T. H. Seligman; 33. Spectral properties of a Fermi accelerating disk R. Badrinarayanan and J. J. José; 34. Spectral properties of systems with dynamical localization T. Dittrich and U. Smilansky; 35. Unbound quantum diffusion and fractal spectra T. Geisel, R. Ketzmerick and G. Petschel; 36. Microwave studies in irregularly shaped billiards H.-J. Stöckmann, J. Stein and M. Kollman; Index.

Cauchy problem in spacetimes with closed timelike curves

NASA Astrophysics Data System (ADS)

Friedman, John; Morris, Michael S.; Novikov, Igor D.; Echeverria, Fernando; Klinkhammer, Gunnar; Thorne, Kip S.; Yurtsever, Ulvi

1990-09-01

The laws of physics might permit the existence, in the real Universe, of closed timelike curves (CTC's). Macroscopic CTC's might be a semiclassical consequence of Planck-scale, quantum gravitational, Lorentzian foam, if such foam exists. If CTC's are permitted, then the semiclassical laws of physics (the laws with gravity classical and other fields quantized or classical) should be augmented by a principle of self-consistency, which states that a local solution to the equations of physics can occur in the real Universe only if it can be extended to be part of a global solution, one which is well defined throughout the (nonsingular regions of) classical spacetime. The consequences of this principle are explored for the Cauchy problem of the evolution of a classical, massless scalar field Φ (satisfying □Φ=0) in several model spacetimes with CTC's. In general, self-consistency constrains the initial data for the field Φ. For a family of spacetimes with traversible wormholes, which initially possess no CTC's and then evolve them to the future of a stable Cauchy horizon scrH, self-consistency seems to place no constraints on initial data for Φ that are posed on past null infinity, and none on data posed on spacelike slices which precede scrH. By contrast, initial data posed in the future of scrH, where the CTC's reside, are constrained; but the constraints appear to be mild in the sense that in some neighborhood of every event one is free to specify initial data arbitrarily, with the initial data elsewhere being adjusted to guarantee self-consistent evolution. A spacetime whose self-consistency constraints have this property is defined to be ``benign with respect to the scalar field Φ.'' The question is posed as to whether benign spacetimes in some sense form a generic subset of all spacetimes with CTC's. It is shown that in the set of flat, spatially and temporally closed, 2-dimensional spacetimes the benign ones are not generic. However, it seems likely that every 4-dimensional, asymptotically flat space-time that is stable and has a topology of the form R×(S-one point), where S is a closed 3-manifold, is benign. Wormhole spacetimes are of this type, with S=S1×S2. We suspect that these types of self-consistency behavior of the scalar field Φ are typical for noninteracting (linearly superposing), classical fields. However, interacting classical systems can behave quite differently, as is demonstrated by a study of the motion of a hard-sphere billiard ball in a wormhole spacetime with closed timelike curves: If the ball is classical, then some choices of initial data (some values of the ball's initial position and velocity) give rise to unique, self-consistent motions of the ball; other choices produce two different self-consistent motions; and others might (but we are not yet sure) produce no self-consistent motions whatsoever. By contrast, in a path-integral formulation of the nonrelativistic quantum mechanics of such a billiard ball, there appears to be a unique, self-consistent set of probabilities for the outcomes of all measurements. This paper's conclusion, that CTC's may not be as nasty as people have assumed, is reinforced by the fact that they do not affect Gauss's theorem and thus do not affect the derivation of global conservation laws from differential ones. The standard conservation laws remain valid globally, and in asymptotically flat, wormhole spacetimes they retain a natural, quasilocal interpretation.

Computer-aided visualization and analysis system for sequence evaluation

DOEpatents

Chee, M.S.

1998-08-18

A computer system for analyzing nucleic acid sequences is provided. The computer system is used to perform multiple methods for determining unknown bases by analyzing the fluorescence intensities of hybridized nucleic acid probes. The results of individual experiments are improved by processing nucleic acid sequences together. Comparative analysis of multiple experiments is also provided by displaying reference sequences in one area and sample sequences in another area on a display device. 27 figs.

Computer-aided visualization and analysis system for sequence evaluation

DOEpatents

Chee, Mark S.; Wang, Chunwei; Jevons, Luis C.; Bernhart, Derek H.; Lipshutz, Robert J.

2004-05-11

A computer system for analyzing nucleic acid sequences is provided. The computer system is used to perform multiple methods for determining unknown bases by analyzing the fluorescence intensities of hybridized nucleic acid probes. The results of individual experiments are improved by processing nucleic acid sequences together. Comparative analysis of multiple experiments is also provided by displaying reference sequences in one area and sample sequences in another area on a display device.

Computer-aided visualization and analysis system for sequence evaluation

DOEpatents

Chee, Mark S.

1998-08-18

A computer system for analyzing nucleic acid sequences is provided. The computer system is used to perform multiple methods for determining unknown bases by analyzing the fluorescence intensities of hybridized nucleic acid probes. The results of individual experiments are improved by processing nucleic acid sequences together. Comparative analysis of multiple experiments is also provided by displaying reference sequences in one area and sample sequences in another area on a display device.

Computer-aided visualization and analysis system for sequence evaluation

DOEpatents

Chee, Mark S.

2003-08-19

A computer system for analyzing nucleic acid sequences is provided. The computer system is used to perform multiple methods for determining unknown bases by analyzing the fluorescence intensities of hybridized nucleic acid probes. The results of individual experiments may be improved by processing nucleic acid sequences together. Comparative analysis of multiple experiments is also provided by displaying reference sequences in one area and sample sequences in another area on a display device.

ALMA test interferometer control system: past experiences and future developments

NASA Astrophysics Data System (ADS)

Marson, Ralph G.; Pokorny, Martin; Kern, Jeff; Stauffer, Fritz; Perrigouard, Alain; Gustafsson, Birger; Ramey, Ken

2004-09-01

The Atacama Large Millimeter Array (ALMA) will, when it is completed in 2012, be the world's largest millimeter & sub-millimeter radio telescope. It will consist of 64 antennas, each one 12 meters in diameter, connected as an interferometer. The ALMA Test Interferometer Control System (TICS) was developed as a prototype for the ALMA control system. Its initial task was to provide sufficient functionality for the evaluation of the prototype antennas. The main antenna evaluation tasks include surface measurements via holography and pointing accuracy, measured at both optical and millimeter wavelengths. In this paper we will present the design of TICS, which is a distributed computing environment. In the test facility there are four computers: three real-time computers running VxWorks (one on each antenna and a central one) and a master computer running Linux. These computers communicate via Ethernet, and each of the real-time computers is connected to the hardware devices via an extension of the CAN bus. We will also discuss our experience with this system and outline changes we are making in light of our experiences.

On the Bayesian Treed Multivariate Gaussian Process with Linear Model of Coregionalization

DOE Office of Scientific and Technical Information (OSTI.GOV)

Konomi, Bledar A.; Karagiannis, Georgios; Lin, Guang

2015-02-01

The Bayesian treed Gaussian process (BTGP) has gained popularity in recent years because it provides a straightforward mechanism for modeling non-stationary data and can alleviate computational demands by fitting models to less data. The extension of BTGP to the multivariate setting requires us to model the cross-covariance and to propose efficient algorithms that can deal with trans-dimensional MCMC moves. In this paper we extend the cross-covariance of the Bayesian treed multivariate Gaussian process (BTMGP) to that of linear model of Coregionalization (LMC) cross-covariances. Different strategies have been developed to improve the MCMC mixing and invert smaller matrices in the Bayesianmore » inference. Moreover, we compare the proposed BTMGP with existing multiple BTGP and BTMGP in test cases and multiphase flow computer experiment in a full scale regenerator of a carbon capture unit. The use of the BTMGP with LMC cross-covariance helped to predict the computer experiments relatively better than existing competitors. The proposed model has a wide variety of applications, such as computer experiments and environmental data. In the case of computer experiments we also develop an adaptive sampling strategy for the BTMGP with LMC cross-covariance function.« less

Framework for emotional mobile computation for creating entertainment experience

NASA Astrophysics Data System (ADS)

Lugmayr, Artur R.

2007-02-01

Ambient media are media, which are manifesting in the natural environment of the consumer. The perceivable borders between the media and the context, where the media is used are getting more and more blurred. The consumer is moving through a digital space of services throughout his daily life. As we are developing towards an experience society, the central point in the development of services is the creation of a consumer experience. This paper reviews possibilities and potentials of the creation of entertainment experiences with mobile phone platforms. It reviews sensor network capable of acquiring consumer behavior data, interactivity strategies, psychological models for emotional computation on mobile phones, and lays the foundations of a nomadic experience society. The paper rounds up with a presentation of several different possible service scenarios in the field of entertainment and leisure computation on mobiles. The goal of this paper is to present a framework and evaluation of possibilities of applying sensor technology on mobile platforms to create an increasing consumer entertainment experience.

Critical Computer Literacy: Computers in First-Year Composition as Topic and Environment.

ERIC Educational Resources Information Center

Duffelmeyer, Barbara Blakely

2000-01-01

Addresses how first-year students understand the influence of computers by cultural assumptions about technology. Presents three meaning perspectives on technology that students expressed based on formative experiences they have had with it. Discusses implications for how computers and composition scholars incorporate computer technology into…

A CAD (Classroom Assessment Design) of a Computer Programming Course

ERIC Educational Resources Information Center

Hawi, Nazir S.

2012-01-01

This paper presents a CAD (classroom assessment design) of an entry-level undergraduate computer programming course "Computer Programming I". CAD has been the product of a long experience in teaching computer programming courses including teaching "Computer Programming I" 22 times. Each semester, CAD is evaluated and modified…

Motivating Contributions for Home Computer Security

ERIC Educational Resources Information Center

Wash, Richard L.

2009-01-01

Recently, malicious computer users have been compromising computers en masse and combining them to form coordinated botnets. The rise of botnets has brought the problem of home computers to the forefront of security. Home computer users commonly have insecure systems; these users do not have the knowledge, experience, and skills necessary to…

Giving Professional Help to Preservice Teachers through Computer-Mediated Communication.

ERIC Educational Resources Information Center

Loiselle, Jean; St-Louis, Mack; Dupuy-Walker, Louise

Two Canadian universities conducted an experiment in which preservice teachers used computer-mediated communication to describe and discuss critical incidents occurring during their practicum. Participants in the practicum shared their teaching experiences with peers, cooperating teachers, and university supervisors. Over 3 years, 6 different…

Computer Simulation of the Population Growth (Schizosaccharomyces Pombe) Experiment.

ERIC Educational Resources Information Center

Daley, Michael; Hillier, Douglas

1981-01-01

Describes a computer program (available from authors) developed to simulate "Growth of a Population (Yeast) Experiment." Students actively revise the counting techniques with realistically simulated haemocytometer or eye-piece grid and are reminded of the necessary dilution technique. Program can be modified to introduce such variables…

Evolution of the Virtualized HPC Infrastructure of Novosibirsk Scientific Center

NASA Astrophysics Data System (ADS)

Adakin, A.; Anisenkov, A.; Belov, S.; Chubarov, D.; Kalyuzhny, V.; Kaplin, V.; Korol, A.; Kuchin, N.; Lomakin, S.; Nikultsev, V.; Skovpen, K.; Sukharev, A.; Zaytsev, A.

2012-12-01

Novosibirsk Scientific Center (NSC), also known worldwide as Akademgorodok, is one of the largest Russian scientific centers hosting Novosibirsk State University (NSU) and more than 35 research organizations of the Siberian Branch of Russian Academy of Sciences including Budker Institute of Nuclear Physics (BINP), Institute of Computational Technologies, and Institute of Computational Mathematics and Mathematical Geophysics (ICM&MG). Since each institute has specific requirements on the architecture of computing farms involved in its research field, currently we've got several computing facilities hosted by NSC institutes, each optimized for a particular set of tasks, of which the largest are the NSU Supercomputer Center, Siberian Supercomputer Center (ICM&MG), and a Grid Computing Facility of BINP. A dedicated optical network with the initial bandwidth of 10 Gb/s connecting these three facilities was built in order to make it possible to share the computing resources among the research communities, thus increasing the efficiency of operating the existing computing facilities and offering a common platform for building the computing infrastructure for future scientific projects. Unification of the computing infrastructure is achieved by extensive use of virtualization technology based on XEN and KVM platforms. This contribution gives a thorough review of the present status and future development prospects for the NSC virtualized computing infrastructure and the experience gained while using it for running production data analysis jobs related to HEP experiments being carried out at BINP, especially the KEDR detector experiment at the VEPP-4M electron-positron collider.

Modeling Subsurface Reactive Flows Using Leadership-Class Computing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mills, Richard T; Hammond, Glenn; Lichtner, Peter

2009-01-01

We describe our experiences running PFLOTRAN - a code for simulation of coupled hydro-thermal-chemical processes in variably saturated, non-isothermal, porous media - on leadership-class supercomputers, including initial experiences running on the petaflop incarnation of Jaguar, the Cray XT5 at the National Center for Computational Sciences at Oak Ridge National Laboratory. PFLOTRAN utilizes fully implicit time-stepping and is built on top of the Portable, Extensible Toolkit for Scientific Computation (PETSc). We discuss some of the hurdles to 'at scale' performance with PFLOTRAN and the progress we have made in overcoming them on leadership-class computer architectures.

Evolution of the ATLAS PanDA workload management system for exascale computational science

NASA Astrophysics Data System (ADS)

Maeno, T.; De, K.; Klimentov, A.; Nilsson, P.; Oleynik, D.; Panitkin, S.; Petrosyan, A.; Schovancova, J.; Vaniachine, A.; Wenaus, T.; Yu, D.; Atlas Collaboration

2014-06-01

An important foundation underlying the impressive success of data processing and analysis in the ATLAS experiment [1] at the LHC [2] is the Production and Distributed Analysis (PanDA) workload management system [3]. PanDA was designed specifically for ATLAS and proved to be highly successful in meeting all the distributed computing needs of the experiment. However, the core design of PanDA is not experiment specific. The PanDA workload management system is capable of meeting the needs of other data intensive scientific applications. Alpha-Magnetic Spectrometer [4], an astro-particle experiment on the International Space Station, and the Compact Muon Solenoid [5], an LHC experiment, have successfully evaluated PanDA and are pursuing its adoption. In this paper, a description of the new program of work to develop a generic version of PanDA will be given, as well as the progress in extending PanDA's capabilities to support supercomputers and clouds and to leverage intelligent networking. PanDA has demonstrated at a very large scale the value of automated dynamic brokering of diverse workloads across distributed computing resources. The next generation of PanDA will allow other data-intensive sciences and a wider exascale community employing a variety of computing platforms to benefit from ATLAS' experience and proven tools.

Statistical Surrogate Modeling of Atmospheric Dispersion Events Using Bayesian Adaptive Splines

NASA Astrophysics Data System (ADS)

Francom, D.; Sansó, B.; Bulaevskaya, V.; Lucas, D. D.

2016-12-01

Uncertainty in the inputs of complex computer models, including atmospheric dispersion and transport codes, is often assessed via statistical surrogate models. Surrogate models are computationally efficient statistical approximations of expensive computer models that enable uncertainty analysis. We introduce Bayesian adaptive spline methods for producing surrogate models that capture the major spatiotemporal patterns of the parent model, while satisfying all the necessities of flexibility, accuracy and computational feasibility. We present novel methodological and computational approaches motivated by a controlled atmospheric tracer release experiment conducted at the Diablo Canyon nuclear power plant in California. Traditional methods for building statistical surrogate models often do not scale well to experiments with large amounts of data. Our approach is well suited to experiments involving large numbers of model inputs, large numbers of simulations, and functional output for each simulation. Our approach allows us to perform global sensitivity analysis with ease. We also present an approach to calibration of simulators using field data.

Propagation of Computational Uncertainty Using the Modern Design of Experiments

NASA Technical Reports Server (NTRS)

DeLoach, Richard

2007-01-01

This paper describes the use of formally designed experiments to aid in the error analysis of a computational experiment. A method is described by which the underlying code is approximated with relatively low-order polynomial graduating functions represented by truncated Taylor series approximations to the true underlying response function. A resource-minimal approach is outlined by which such graduating functions can be estimated from a minimum number of case runs of the underlying computational code. Certain practical considerations are discussed, including ways and means of coping with high-order response functions. The distributional properties of prediction residuals are presented and discussed. A practical method is presented for quantifying that component of the prediction uncertainty of a computational code that can be attributed to imperfect knowledge of independent variable levels. This method is illustrated with a recent assessment of uncertainty in computational estimates of Space Shuttle thermal and structural reentry loads attributable to ice and foam debris impact on ascent.

The experience of agency in human-computer interactions: a review

PubMed Central

Limerick, Hannah; Coyle, David; Moore, James W.

2014-01-01

The sense of agency is the experience of controlling both one’s body and the external environment. Although the sense of agency has been studied extensively, there is a paucity of studies in applied “real-life” situations. One applied domain that seems highly relevant is human-computer-interaction (HCI), as an increasing number of our everyday agentive interactions involve technology. Indeed, HCI has long recognized the feeling of control as a key factor in how people experience interactions with technology. The aim of this review is to summarize and examine the possible links between sense of agency and understanding control in HCI. We explore the overlap between HCI and sense of agency for computer input modalities and system feedback, computer assistance, and joint actions between humans and computers. An overarching consideration is how agency research can inform HCI and vice versa. Finally, we discuss the potential ethical implications of personal responsibility in an ever-increasing society of technology users and intelligent machine interfaces. PMID:25191256

Discovery & Interaction in Astro 101 Laboratory Experiments

NASA Astrophysics Data System (ADS)

Maloney, Frank Patrick; Maurone, Philip; DeWarf, Laurence E.

2016-01-01

The availability of low-cost, high-performance computing hardware and software has transformed the manner by which astronomical concepts can be re-discovered and explored in a laboratory that accompanies an astronomy course for arts students. We report on a strategy, begun in 1992, for allowing each student to understand fundamental scientific principles by interactively confronting astronomical and physical phenomena, through direct observation and by computer simulation. These experiments have evolved as :a) the quality and speed of the hardware has greatly increasedb) the corresponding hardware costs have decreasedc) the students have become computer and Internet literated) the importance of computationally and scientifically literate arts graduates in the workplace has increased.We present the current suite of laboratory experiments, and describe the nature, procedures, and goals in this two-semester laboratory for liberal arts majors at the Astro 101 university level.

Profile modification computations for LHCD experiments on PBX-M using the TSC/LSC model

NASA Astrophysics Data System (ADS)

Kaita, R.; Ignat, D. W.; Jardin, S. C.; Okabayashi, M.; Sun, Y. C.

1996-02-01

The TSC-LSC computational model of the dynamics of lower hybrid current drive has been exercised extensively in comparison with data from a Princeton Beta Experiment-Modification (PBX-M) discharge where the measured q(0) attained values slightly above unity. Several significant, but plausible, assumptions had to be introduced to keep the computation from behaving pathologically over time, producing singular profiles of plasma current density and q. Addition of a heuristic current diffusion estimate, or more exactly, a smoothing of the rf-driven current with a diffusion-like equation, greatly improved the behavior of the computation, and brought theory and measurement into reasonable agreement. The model was then extended to longer pulse lengths and higher powers to investigate performance to be expected in future PBX-M current profile modification experiments.

TREAT Reactor Control and Protection System

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lipinski, W.C.; Brookshier, W.K.; Burrows, D.R.

1985-01-01

The main control algorithm of the Transient Reactor Test Facility (TREAT) Automatic Reactor Control System (ARCS) resides in Read Only Memory (ROM) and only experiment specific parameters are input via keyboard entry. Prior to executing an experiment, the software and hardware of the control computer is tested by a closed loop real-time simulation. Two computers with parallel processing are used for the reactor simulation and another computer is used for simulation of the control rod system. A monitor computer, used as a redundant diverse reactor protection channel, uses more conservative setpoints and reduces challenges to the Reactor Trip System (RTS).more » The RTS consists of triplicated hardwired channels with one out of three logic. The RTS is automatically tested by a digital Dedicated Microprocessor Tester (DMT) prior to the execution of an experiment. 6 refs., 5 figs., 1 tab.« less

Development and Flight Results of a PC104/QNX-Based On-Board Computer and Software for the YES2 Tether Experiment

NASA Astrophysics Data System (ADS)

Spiliotopoulos, I.; Mirmont, M.; Kruijff, M.

2008-08-01

This paper highlights the flight preparation and mission performance of a PC104-based On-Board Computer for ESA's second Young Engineer's Satellite (YES2), with additional attention to the flight software design and experience of QNX as multi-process real-time operating system. This combination of Commercial-Of-The-Shelf (COTS) technologies is an accessible option for small satellites with high computational demands.

Computer-aided visualization and analysis system for sequence evaluation

DOEpatents

Chee, Mark S.

1999-10-26

A computer system (1) for analyzing nucleic acid sequences is provided. The computer system is used to perform multiple methods for determining unknown bases by analyzing the fluorescence intensities of hybridized nucleic acid probes. The results of individual experiments may be improved by processing nucleic acid sequences together. Comparative analysis of multiple experiments is also provided by displaying reference sequences in one area (814) and sample sequences in another area (816) on a display device (3).

Computer-aided visualization and analysis system for sequence evaluation

DOEpatents

Chee, Mark S.

2001-06-05

A computer system (1) for analyzing nucleic acid sequences is provided. The computer system is used to perform multiple methods for determining unknown bases by analyzing the fluorescence intensities of hybridized nucleic acid probes. The results of individual experiments may be improved by processing nucleic acid sequences together. Comparative analysis of multiple experiments is also provided by displaying reference sequences in one area (814) and sample sequences in another area (816) on a display device (3).

Dynamic Fracture Simulations of Explosively Loaded Cylinders

DOE Office of Scientific and Technical Information (OSTI.GOV)

Arthur, Carly W.; Goto, D. M.

2015-11-30

This report documents the modeling results of high explosive experiments investigating dynamic fracture of steel (AerMet® 100 alloy) cylinders. The experiments were conducted at Lawrence Livermore National Laboratory (LLNL) during 2007 to 2008 [10]. A principal objective of this study was to gain an understanding of dynamic material failure through the analysis of hydrodynamic computer code simulations. Two-dimensional and three-dimensional computational cylinder models were analyzed using the ALE3D multi-physics computer code.

Use of Tablet Computers to Promote Physical Therapy Students' Engagement in Knowledge Translation During Clinical Experiences.

PubMed

Tilson, Julie K; Loeb, Kathryn; Barbosa, Sabrina; Jiang, Fei; Lee, Karin T

2016-04-01

Physical therapists strive to integrate research into daily practice. The tablet computer is a potentially transformational tool for accessing information within the clinical practice environment. The purpose of this study was to measure and describe patterns of tablet computer use among physical therapy students during clinical rotation experiences. Doctor of physical therapy students (n = 13 users) tracked their use of tablet computers (iPad), loaded with commercially available apps, during 16 clinical experiences (6-16 weeks in duration). The tablets were used on 70% of 691 clinic days, averaging 1.3 uses per day. Information seeking represented 48% of uses; 33% of those were foreground searches for research articles and syntheses and 66% were for background medical information. Other common uses included patient education (19%), medical record documentation (13%), and professional communication (9%). The most frequently used app was Safari, the preloaded web browser (representing 281 [36.5%] incidents of use). Users accessed 56 total apps to support clinical practice. Physical therapy students successfully integrated use of a tablet computer into their clinical experiences including regular activities of information seeking. Our findings suggest that the tablet computer represents a potentially transformational tool for promoting knowledge translation in the clinical practice environment.Video Abstract available for more insights from the authors (see Supplemental Digital Content 1, http://links.lww.com/JNPT/A127).

Science Support for Space-Based Droplet Combustion: Drop Tower Experiments and Detailed Numerical Modeling

NASA Technical Reports Server (NTRS)

Marchese, Anthony J.; Dryer, Frederick L.

1997-01-01

This program supports the engineering design, data analysis, and data interpretation requirements for the study of initially single component, spherically symmetric, isolated droplet combustion studies. Experimental emphasis is on the study of simple alcohols (methanol, ethanol) and alkanes (n-heptane, n-decane) as fuels with time dependent measurements of drop size, flame-stand-off, liquid-phase composition, and finally, extinction. Experiments have included bench-scale studies at Princeton, studies in the 2.2 and 5.18 drop towers at NASA-LeRC, and both the Fiber Supported Droplet Combustion (FSDC-1, FSDC-2) and the free Droplet Combustion Experiment (DCE) studies aboard the shuttle. Test matrix and data interpretation are performed through spherically-symmetric, time-dependent numerical computations which embody detailed sub-models for physical and chemical processes. The computed burning rate, flame stand-off, and extinction diameter are compared with the respective measurements for each individual experiment. In particular, the data from FSDC-1 and subsequent space-based experiments provide the opportunity to compare all three types of data simultaneously with the computed parameters. Recent numerical efforts are extending the computational tools to consider time dependent, axisymmetric 2-dimensional reactive flow situations.

Classical boson sampling algorithms with superior performance to near-term experiments

NASA Astrophysics Data System (ADS)

Neville, Alex; Sparrow, Chris; Clifford, Raphaël; Johnston, Eric; Birchall, Patrick M.; Montanaro, Ashley; Laing, Anthony

2017-12-01

It is predicted that quantum computers will dramatically outperform their conventional counterparts. However, large-scale universal quantum computers are yet to be built. Boson sampling is a rudimentary quantum algorithm tailored to the platform of linear optics, which has sparked interest as a rapid way to demonstrate such quantum supremacy. Photon statistics are governed by intractable matrix functions, which suggests that sampling from the distribution obtained by injecting photons into a linear optical network could be solved more quickly by a photonic experiment than by a classical computer. The apparently low resource requirements for large boson sampling experiments have raised expectations of a near-term demonstration of quantum supremacy by boson sampling. Here we present classical boson sampling algorithms and theoretical analyses of prospects for scaling boson sampling experiments, showing that near-term quantum supremacy via boson sampling is unlikely. Our classical algorithm, based on Metropolised independence sampling, allowed the boson sampling problem to be solved for 30 photons with standard computing hardware. Compared to current experiments, a demonstration of quantum supremacy over a successful implementation of these classical methods on a supercomputer would require the number of photons and experimental components to increase by orders of magnitude, while tackling exponentially scaling photon loss.

Evaluating the Relationship of Computer Literacy Training Competence and Nursing Experience to CPIS Resistance

ERIC Educational Resources Information Center

Reese, Dorothy J.

2012-01-01

The purpose of this quantitative, descriptive/correlational project was to examine the relationship between the level of computer literacy, informatics training, nursing experience, and perceived competence in using computerized patient information systems (CPIS) and nursing resistance to using CPIS. The Nurse Computerized Patient Information…

Instruction Using Experiments in a Computer. Final Report.

ERIC Educational Resources Information Center

Fulton, John P.; Hazeltine, Barrett

Included are four computer programs which simulate experiments suitable for freshman engineering and physics courses. The subjects of the programs are ballistic trajectories, variable mass systems, trajectory of a particle under various forces, and design of an electronic emplifier. The report includes the problem statement, its objectives, the…

Computer Simulation of Laboratory Experiments: An Unrealized Potential.

ERIC Educational Resources Information Center

Magin, D. J.; Reizes, J. A.

1990-01-01

Discussion of the use of computer simulation for laboratory experiments in undergraduate engineering education focuses on work at the University of New South Wales in the instructional design and software development of a package simulating a heat exchange device. The importance of integrating theory, design, and experimentation is also discussed.…

Modelling and Simulation as a Recognizing Method in Education

ERIC Educational Resources Information Center

Stoffa, Veronika

2004-01-01

Computer animation-simulation models of complex processes and events, which are the method of instruction, can be an effective didactic device. Gaining deeper knowledge about objects modelled helps to plan simulation experiments oriented on processes and events researched. Animation experiments realized on multimedia computers can aid easier…

Instructional Styles, Attitudes and Experiences of Seniors in Computer Workshops

ERIC Educational Resources Information Center

Wood, Eileen; Lanuza, Catherine; Baciu, Iuliana; MacKenzie, Meagan; Nosko, Amanda

2010-01-01

Sixty-four seniors were introduced to computers through a series of five weekly workshops. Participants were given instruction followed by hands-on experience for topics related to social communication, information seeking, games, and word processing and were observed to determine their preferences for instructional support. Observations of…

Computer Spectrometers

NASA Astrophysics Data System (ADS)

Dattani, Nikesh S.

2017-06-01

Ideally, the cataloguing of spectroscopic linelists would not demand laborious and expensive experiments. Whatever an experiment might achieve, the same information would be attainable by running a calculation on a computer. Kolos and Wolniewicz were the first to demonstrate that calculations on a computer can outperform even the most sophisticated molecular spectroscopic experiments of the time, when their 1964 calculations of the dissociation energies of H_2 and D_{2} were found to be more than 1 cm^{-1} larger than the best experiments by Gerhard Herzberg, suggesting the experiment violated a strict variational principle. As explained in his Nobel Lecture, it took 5 more years for Herzberg to perform an experiment which caught up to the accuracy of the 1964 calculations. Today, numerical solutions to the Schrödinger equation, supplemented with relativistic and higher-order quantum electrodynamics (QED) corrections can provide ro-vibrational spectra for molecules that we strongly believe to be correct, even in the absence of experimental data. Why do we believe these calculated spectra are correct if we do not have experiments against which to test them? All evidence seen so far suggests that corrections due to gravity or other forces are not needed for a computer simulated QED spectrum of ro-vibrational energy transitions to be correct at the precision of typical spectrometers. Therefore a computer-generated spectrum can be considered to be as good as one coming from a more conventional spectrometer, and this has been shown to be true not just for the H_2 energies back in 1964, but now also for several other molecules. So are we at the stage where we can launch an array of calculations, each with just the atomic number changed in the input file, to reproduce the NIST energy level databases? Not quite. But I will show that for the 6e^- molecule Li_2, we have reproduced the vibrational spacings to within 0.001 cm^{-1} of the experimental spectrum, and I will discuss present-day prospects for replacing laborious experiments for spectra of certain systems within the reach of today's ``computer spectrometers''.

Children's Computers.

ERIC Educational Resources Information Center

Samaras, Anastasia P.

1996-01-01

Suggests that teachers and social context determine what young children acquire from computer experiences. Provides anecdotes of teachers working with children who are using a computer program to complete a picture puzzle. The computer allowed teachers to present a problem, witness children's cognitive capabilities, listen to their metacognitive…

Inquiring Minds

Science.gov Websites

Proposed Projects and Experiments Fermilab's Tevatron Questions for the Universe Theory Computing High -performance Computing Grid Computing Networking Mass Storage Plan for the Future State of the Laboratory Homeland Security Industry Computing Sciences Workforce Development A Growing List Historic Results

Kenny Gruchalla | NREL

Science.gov Websites

feature extraction, human-computer interaction, and physics-based modeling. Professional Experience 2009 ., computer science, University of Colorado at Boulder M.S., computer science, University of Colorado at Boulder B.S., computer science, New Mexico Institute of Mining and Technology

78 FR 10180 - Annual Computational Science Symposium; Conference

Federal Register 2010, 2011, 2012, 2013, 2014

2013-02-13

...] Annual Computational Science Symposium; Conference AGENCY: Food and Drug Administration, HHS. ACTION... Computational Science Symposium.'' The purpose of the conference is to help the broader community align and share experiences to advance computational science. At the conference, which will bring together FDA...

Robotic laboratory for distance education

NASA Astrophysics Data System (ADS)

Luciano, Sarah C.; Kost, Alan R.

2016-09-01

This project involves the construction of a remote-controlled laboratory experiment that can be accessed by online students. The project addresses a need to provide a laboratory experience for students who are taking online courses to be able to provide an in-class experience. The chosen task for the remote user is an optical engineering experiment, specifically aligning a spatial filter. We instrument the physical laboratory set up in Tucson, AZ at the University of Arizona. The hardware in the spatial filter experiment is augmented by motors and cameras to allow the user to remotely control the hardware. The user interacts with a software on their computer, which communicates with a server via Internet connection to the host computer in the Optics Laboratory at the University of Arizona. Our final overall system is comprised of several subsystems. These are the optical experiment set-up, which is a spatial filter experiment; the mechanical subsystem, which interfaces the motors with the micrometers to move the optical hardware; the electrical subsystem, which allows for the electrical communications from the remote computer to the host computer to the hardware; and finally the software subsystem, which is the means by which messages are communicated throughout the system. The goal of the project is to convey as much of an in-lab experience as possible by allowing the user to directly manipulate hardware and receive visual feedback in real-time. Thus, the remote user is able to learn important concepts from this particular experiment and is able to connect theory to the physical world by actually seeing the outcome of a procedure. The latter is a learning experience that is often lost with distance learning and is one that this project hopes to provide.

The Use of Computer Technology by Older Adults.

ERIC Educational Resources Information Center

Galusha, Jill M.

The older adult (55+) population is becoming a significant presence in the personal computer market. Seniors have the discretionary income, experience, interest, and free time to make use of computers in interesting ways. A literature review found that older adults make use of computers in significant numbers: 30 percent of computer owners are…

The Ghost of Computers Past, Present, and Future: Computer Use for Preservice/Inservice Reading Programs.

ERIC Educational Resources Information Center

Prince, Amber T.

Computer assisted instruction, and especially computer simulations, can help to ensure that preservice and inservice teachers learn from the right experiences. In the past, colleges of education used large mainframe computer systems to store student registration, provide simulation lessons on diagnosing reading difficulties, construct informal…

Can Computers Be Used Successfully for Teaching College Mathematics?

ERIC Educational Resources Information Center

Hatfield, Steven H.

1976-01-01

Author states that the use of computers in mathematics courses tends to generate interest in course subject matter and make learning a less passive experience. Computers also introduce students to computer science as a field of study, and provide basic knowledge of computers as an important aspect of today's technology. (Author/RW)

Health workers’ knowledge of and attitudes towards computer applications in rural African health facilities

PubMed Central

Sukums, Felix; Mensah, Nathan; Mpembeni, Rose; Kaltschmidt, Jens; Haefeli, Walter E.; Blank, Antje

2014-01-01

Background The QUALMAT (Quality of Maternal and Prenatal Care: Bridging the Know-do Gap) project has introduced an electronic clinical decision support system (CDSS) for pre-natal and maternal care services in rural primary health facilities in Burkina Faso, Ghana, and Tanzania. Objective To report an assessment of health providers’ computer knowledge, experience, and attitudes prior to the implementation of the QUALMAT electronic CDSS. Design A cross-sectional study was conducted with providers in 24 QUALMAT project sites. Information was collected using structured questionnaires. Chi-squared tests and one-way ANOVA describe the association between computer knowledge, attitudes, and other factors. Semi-structured interviews and focus groups were conducted to gain further insights. Results A total of 108 providers responded, 63% were from Tanzania and 37% from Ghana. The mean age was 37.6 years, and 79% were female. Only 40% had ever used computers, and 29% had prior computer training. About 80% were computer illiterate or beginners. Educational level, age, and years of work experience were significantly associated with computer knowledge (p<0.01). Most (95.3%) had positive attitudes towards computers – average score (±SD) of 37.2 (±4.9). Females had significantly lower scores than males. Interviews and group discussions showed that although most were lacking computer knowledge and experience, they were optimistic about overcoming challenges associated with the introduction of computers in their workplace. Conclusions Given the low levels of computer knowledge among rural health workers in Africa, it is important to provide adequate training and support to ensure the successful uptake of electronic CDSSs in these settings. The positive attitudes to computers found in this study underscore that also rural care providers are ready to use such technology. PMID:25361721

Health workers' knowledge of and attitudes towards computer applications in rural African health facilities.

PubMed

Sukums, Felix; Mensah, Nathan; Mpembeni, Rose; Kaltschmidt, Jens; Haefeli, Walter E; Blank, Antje

2014-01-01

The QUALMAT (Quality of Maternal and Prenatal Care: Bridging the Know-do Gap) project has introduced an electronic clinical decision support system (CDSS) for pre-natal and maternal care services in rural primary health facilities in Burkina Faso, Ghana, and Tanzania. To report an assessment of health providers' computer knowledge, experience, and attitudes prior to the implementation of the QUALMAT electronic CDSS. A cross-sectional study was conducted with providers in 24 QUALMAT project sites. Information was collected using structured questionnaires. Chi-squared tests and one-way ANOVA describe the association between computer knowledge, attitudes, and other factors. Semi-structured interviews and focus groups were conducted to gain further insights. A total of 108 providers responded, 63% were from Tanzania and 37% from Ghana. The mean age was 37.6 years, and 79% were female. Only 40% had ever used computers, and 29% had prior computer training. About 80% were computer illiterate or beginners. Educational level, age, and years of work experience were significantly associated with computer knowledge (p<0.01). Most (95.3%) had positive attitudes towards computers - average score (±SD) of 37.2 (±4.9). Females had significantly lower scores than males. Interviews and group discussions showed that although most were lacking computer knowledge and experience, they were optimistic about overcoming challenges associated with the introduction of computers in their workplace. Given the low levels of computer knowledge among rural health workers in Africa, it is important to provide adequate training and support to ensure the successful uptake of electronic CDSSs in these settings. The positive attitudes to computers found in this study underscore that also rural care providers are ready to use such technology.

Challenges to Software/Computing for Experimentation at the LHC

NASA Astrophysics Data System (ADS)

Banerjee, Sunanda

The demands of future high energy physics experiments towards software and computing have led the experiments to plan the related activities as a full-fledged project and to investigate new methodologies and languages to meet the challenges. The paths taken by the four LHC experiments ALICE, ATLAS, CMS and LHCb are coherently put together in an LHC-wide framework based on Grid technology. The current status and understandings have been broadly outlined.

Experimental Tests of Normative Group Influence and Representation Effects in Computer-Mediated Communication: When Interacting Via Computers Differs from Interacting With Computers.

ERIC Educational Resources Information Center

Lee, Eun-Ju; Nass, Clifford

2002-01-01

Presents two experiments to address the questions of if and how normative social influence operates in anonymous computer-mediated communication and human-computer interaction. Finds that the perception of interaction partner (human vs. computer) moderated the group conformity effect such that the undergraduate student subjects expressed greater…

Gender Issues in Technology Use: Perceived Social Support, Computer Self-Efficacy and Value Beliefs, and Computer Use beyond School

ERIC Educational Resources Information Center

Vekiri, Ioanna; Chronaki, Anna

2008-01-01

In this study, we examined relations between outside school computer experiences, perceived social support for using computers, and self-efficacy and value beliefs about computer learning for 340 Greek elementary school boys and girls. Participants responded to a questionnaire about their access to computer use outside school (e.g. frequency of…

Students Enrolled in Selected Upper-Division Agriculture Courses: An Examination of Computer Experiences, Self-Efficacy and Knowledge.

ERIC Educational Resources Information Center

Johnson, Donald M.; Ferguson, James A.; Lester, Melissa L.

2000-01-01

Of 169 agriculture students surveyed, 79% had computer training, 66% owned computers; they had slightly above average computer self-efficacy, especially in word processing, electronic mail, and Internet use. However, 72.7% scored 60% or less on a test of computer knowledge. There was little correlation between self-efficacy and computer knowledge.…

Development of user guidelines for ECAS display design, volume 1

NASA Technical Reports Server (NTRS)

Dodson, D. W.; Shields, N. L., Jr.

1978-01-01

Experiment computer application software (ECAS) display design and command usage guidelines were developed, which if followed by spacelab experiments, would standardize methods and techniques for data presentation and commanding via ECAS. These guidelines would provide some commonality among experiments which would enhance crew training and flight operations. The guidelines are applicable to all onboard experiment displays, whether allocated by ECAS or a dedicated experiment processor. A brief description of the spacelab data display system characteristics and of the services provided by the experiment computer operating system is included. Guidelines concerning data presentation and layout of alphanumeric and graphic information are presented along with guidelines concerning keyboard commanding and command feedback.

Thermal and orbital analysis of Earth monitoring Sun-synchronous space experiments

NASA Technical Reports Server (NTRS)

Killough, Brian D.

1990-01-01

The fundamentals of an Earth monitoring Sun-synchronous orbit are presented. A Sun-synchronous Orbit Analysis Program (SOAP) was developed to calculate orbital parameters for an entire year. The output from this program provides the required input data for the TRASYS thermal radiation computer code, which in turn computes the infrared, solar and Earth albedo heat fluxes incident on a space experiment. Direct incident heat fluxes can be used as input to a generalized thermal analyzer program to size radiators and predict instrument operating temperatures. The SOAP computer code and its application to the thermal analysis methodology presented, should prove useful to the thermal engineer during the design phases of Earth monitoring Sun-synchronous space experiments.

Towards Better Human Robot Interaction: Understand Human Computer Interaction in Social Gaming Using a Video-Enhanced Diary Method

NASA Astrophysics Data System (ADS)

See, Swee Lan; Tan, Mitchell; Looi, Qin En

This paper presents findings from a descriptive research on social gaming. A video-enhanced diary method was used to understand the user experience in social gaming. From this experiment, we found that natural human behavior and gamer’s decision making process can be elicited and speculated during human computer interaction. These are new information that we should consider as they can help us build better human computer interfaces and human robotic interfaces in future.

Internal fluid mechanics research on supercomputers for aerospace propulsion systems

NASA Technical Reports Server (NTRS)

Miller, Brent A.; Anderson, Bernhard H.; Szuch, John R.

1988-01-01

The Internal Fluid Mechanics Division of the NASA Lewis Research Center is combining the key elements of computational fluid dynamics, aerothermodynamic experiments, and advanced computational technology to bring internal computational fluid mechanics (ICFM) to a state of practical application for aerospace propulsion systems. The strategies used to achieve this goal are to: (1) pursue an understanding of flow physics, surface heat transfer, and combustion via analysis and fundamental experiments, (2) incorporate improved understanding of these phenomena into verified 3-D CFD codes, and (3) utilize state-of-the-art computational technology to enhance experimental and CFD research. Presented is an overview of the ICFM program in high-speed propulsion, including work in inlets, turbomachinery, and chemical reacting flows. Ongoing efforts to integrate new computer technologies, such as parallel computing and artificial intelligence, into high-speed aeropropulsion research are described.

Experimental Realization of High-Efficiency Counterfactual Computation.

PubMed

Kong, Fei; Ju, Chenyong; Huang, Pu; Wang, Pengfei; Kong, Xi; Shi, Fazhan; Jiang, Liang; Du, Jiangfeng

2015-08-21

Counterfactual computation (CFC) exemplifies the fascinating quantum process by which the result of a computation may be learned without actually running the computer. In previous experimental studies, the counterfactual efficiency is limited to below 50%. Here we report an experimental realization of the generalized CFC protocol, in which the counterfactual efficiency can break the 50% limit and even approach unity in principle. The experiment is performed with the spins of a negatively charged nitrogen-vacancy color center in diamond. Taking advantage of the quantum Zeno effect, the computer can remain in the not-running subspace due to the frequent projection by the environment, while the computation result can be revealed by final detection. The counterfactual efficiency up to 85% has been demonstrated in our experiment, which opens the possibility of many exciting applications of CFC, such as high-efficiency quantum integration and imaging.

Experimental Realization of High-Efficiency Counterfactual Computation

NASA Astrophysics Data System (ADS)

Kong, Fei; Ju, Chenyong; Huang, Pu; Wang, Pengfei; Kong, Xi; Shi, Fazhan; Jiang, Liang; Du, Jiangfeng

2015-08-01

Counterfactual computation (CFC) exemplifies the fascinating quantum process by which the result of a computation may be learned without actually running the computer. In previous experimental studies, the counterfactual efficiency is limited to below 50%. Here we report an experimental realization of the generalized CFC protocol, in which the counterfactual efficiency can break the 50% limit and even approach unity in principle. The experiment is performed with the spins of a negatively charged nitrogen-vacancy color center in diamond. Taking advantage of the quantum Zeno effect, the computer can remain in the not-running subspace due to the frequent projection by the environment, while the computation result can be revealed by final detection. The counterfactual efficiency up to 85% has been demonstrated in our experiment, which opens the possibility of many exciting applications of CFC, such as high-efficiency quantum integration and imaging.

Computer-based communication in support of scientific and technical work. [conferences on management information systems used by scientists of NASA programs

NASA Technical Reports Server (NTRS)

Vallee, J.; Wilson, T.

1976-01-01

Results are reported of the first experiments for a computer conference management information system at the National Aeronautics and Space Administration. Between August 1975 and March 1976, two NASA projects with geographically separated participants (NASA scientists) used the PLANET computer conferencing system for portions of their work. The first project was a technology assessment of future transportation systems. The second project involved experiments with the Communication Technology Satellite. As part of this project, pre- and postlaunch operations were discussed in a computer conference. These conferences also provided the context for an analysis of the cost of computer conferencing. In particular, six cost components were identified: (1) terminal equipment, (2) communication with a network port, (3) network connection, (4) computer utilization, (5) data storage and (6) administrative overhead.

Cyber-workstation for computational neuroscience.

PubMed

Digiovanna, Jack; Rattanatamrong, Prapaporn; Zhao, Ming; Mahmoudi, Babak; Hermer, Linda; Figueiredo, Renato; Principe, Jose C; Fortes, Jose; Sanchez, Justin C

2010-01-01

A Cyber-Workstation (CW) to study in vivo, real-time interactions between computational models and large-scale brain subsystems during behavioral experiments has been designed and implemented. The design philosophy seeks to directly link the in vivo neurophysiology laboratory with scalable computing resources to enable more sophisticated computational neuroscience investigation. The architecture designed here allows scientists to develop new models and integrate them with existing models (e.g. recursive least-squares regressor) by specifying appropriate connections in a block-diagram. Then, adaptive middleware transparently implements these user specifications using the full power of remote grid-computing hardware. In effect, the middleware deploys an on-demand and flexible neuroscience research test-bed to provide the neurophysiology laboratory extensive computational power from an outside source. The CW consolidates distributed software and hardware resources to support time-critical and/or resource-demanding computing during data collection from behaving animals. This power and flexibility is important as experimental and theoretical neuroscience evolves based on insights gained from data-intensive experiments, new technologies and engineering methodologies. This paper describes briefly the computational infrastructure and its most relevant components. Each component is discussed within a systematic process of setting up an in vivo, neuroscience experiment. Furthermore, a co-adaptive brain machine interface is implemented on the CW to illustrate how this integrated computational and experimental platform can be used to study systems neurophysiology and learning in a behavior task. We believe this implementation is also the first remote execution and adaptation of a brain-machine interface.

Cyber-Workstation for Computational Neuroscience

PubMed Central

DiGiovanna, Jack; Rattanatamrong, Prapaporn; Zhao, Ming; Mahmoudi, Babak; Hermer, Linda; Figueiredo, Renato; Principe, Jose C.; Fortes, Jose; Sanchez, Justin C.

2009-01-01

A Cyber-Workstation (CW) to study in vivo, real-time interactions between computational models and large-scale brain subsystems during behavioral experiments has been designed and implemented. The design philosophy seeks to directly link the in vivo neurophysiology laboratory with scalable computing resources to enable more sophisticated computational neuroscience investigation. The architecture designed here allows scientists to develop new models and integrate them with existing models (e.g. recursive least-squares regressor) by specifying appropriate connections in a block-diagram. Then, adaptive middleware transparently implements these user specifications using the full power of remote grid-computing hardware. In effect, the middleware deploys an on-demand and flexible neuroscience research test-bed to provide the neurophysiology laboratory extensive computational power from an outside source. The CW consolidates distributed software and hardware resources to support time-critical and/or resource-demanding computing during data collection from behaving animals. This power and flexibility is important as experimental and theoretical neuroscience evolves based on insights gained from data-intensive experiments, new technologies and engineering methodologies. This paper describes briefly the computational infrastructure and its most relevant components. Each component is discussed within a systematic process of setting up an in vivo, neuroscience experiment. Furthermore, a co-adaptive brain machine interface is implemented on the CW to illustrate how this integrated computational and experimental platform can be used to study systems neurophysiology and learning in a behavior task. We believe this implementation is also the first remote execution and adaptation of a brain-machine interface. PMID:20126436

Impact of IQ, computer-gaming skills, general dexterity, and laparoscopic experience on performance with the da Vinci surgical system.

PubMed

Hagen, Monika E; Wagner, Oliver J; Inan, Ihsan; Morel, Philippe

2009-09-01

Due to improved ergonomics and dexterity, robotic surgery is promoted as being easily performed by surgeons with no special skills necessary. We tested this hypothesis by measuring IQ elements, computer gaming skills, general dexterity with chopsticks, and evaluating laparoscopic experience in correlation to performance ability with the da Vinci robot. Thirty-four individuals were tested for robotic dexterity, IQ elements, computer-gaming skills and general dexterity. Eighteen surgically inexperienced and 16 laparoscopically trained surgeons were included. Each individual performed three different tasks with the da Vinci surgical system and their times were recorded. An IQ test (elements: logical thinking, 3D imagination and technical understanding) was completed by each participant. Computer skills were tested with a simple computer game (hand-eye coordination) and general dexterity was evaluated by the ability to use chopsticks. We found no correlation between logical thinking, 3D imagination and robotic skills. Both computer gaming and general dexterity showed a slight but non-significant improvement in performance with the da Vinci robot (p > 0.05). A significant correlation between robotic skills, technical understanding and laparoscopic experience was observed (p < 0.05). The data support the conclusion that there are no significant correlations between robotic performance and logical thinking, 3D understanding, computer gaming skills and general dexterity. A correlation between robotic skills and technical understanding may exist. Laparoscopic experience seems to be the strongest predictor of performance with the da Vinci surgical system. Generally, it appears difficult to determine non-surgical predictors for robotic surgery.

Experience with a sophisticated computer based authoring system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gardner, P.R.

1984-04-01

In the November 1982 issue of ADCIS SIG CBT Newsletter the editor arrives at two conclusions regarding Computer Based Authoring Systems (CBAS): (1) CBAS drastically reduces programming time and the need for expert programmers, and (2) CBAS appears to have minimal impact on initial lesson design. Both of these comments have significant impact on any Cost-Benefit analysis for Computer-Based Training. The first tends to improve cost-effectiveness but only toward the limits imposed by the second. Westinghouse Hanford Company (WHC) recently purchased a sophisticated CBAS, the WISE/SMART system from Wicat (Orem, UT), for use in the Nuclear Power Industry. This reportmore » details our experience with this system relative to Items (1) and (2) above; lesson design time will be compared with lesson input time. Also provided will be the WHC experience in the use of subject matter experts (though computer neophytes) for the design and inputting of CBT materials.« less

The Computer as a Tool for Learning

PubMed Central

Starkweather, John A.

1986-01-01

Experimenters from the beginning recognized the advantages computers might offer in medical education. Several medical schools have gained experience in such programs in automated instruction. Television images and graphic display combined with computer control and user interaction are effective for teaching problem solving. The National Board of Medical Examiners has developed patient-case simulation for examining clinical skills, and the National Library of Medicine has experimented with combining media. Advances from the field of artificial intelligence and the availability of increasingly powerful microcomputers at lower cost will aid further development. Computers will likely affect existing educational methods, adding new capabilities to laboratory exercises, to self-assessment and to continuing education. PMID:3544511

Physician Utilization of a Hospital Information System: A Computer Simulation Model

PubMed Central

Anderson, James G.; Jay, Stephen J.; Clevenger, Stephen J.; Kassing, David R.; Perry, Jane; Anderson, Marilyn M.

1988-01-01

The purpose of this research was to develop a computer simulation model that represents the process through which physicians enter orders into a hospital information system (HIS). Computer simulation experiments were performed to estimate the effects of two methods of order entry on outcome variables. The results of the computer simulation experiments were used to perform a cost-benefit analysis to compare the two different means of entering medical orders into the HIS. The results indicate that the use of personal order sets to enter orders into the HIS will result in a significant reduction in manpower, salaries and fringe benefits, and errors in order entry.

Computational Investigations for Undergraduate Organic Chemistry: Predicting the Mechanism of the Ritter Reaction

NASA Astrophysics Data System (ADS)

Hessley, Rita K.

2000-02-01

In an effort to engage students more deeply in their laboratory work and provide them with valuable learning experiences in the applications and limitations of computational chemistry as a research tool, students are instructed to carry out a computational pre-lab exercise. Before carrying out a laboratory experiment that investigates the mechanism for the formation of N-t-butylbenzamide, students construct and obtain heats of formation for reactants, products, postulated reaction intermediates, and one transition state structure for each proposed mechanism. This is designed as a companion to an open-ended laboratory experiment that hones skills learned early in most traditional organic chemistry courses. The incorporation of a preliminary computational exercise enables students to move beyond guessing what the outcome of the reaction will be. It challenges them to test what they believe they "know" about such fundamental concepts as stability of carbocations, or the significance and utility of thermodynamic data relative to kinetic data. On the basis of their computations and their own experimental data, students then verify or dispute their hypothesis, finally arriving at a defensible and logical conclusion about the course of the reaction mechanism. The manner of implementation of the exercise and typical computational data are described.

Games at work: the recreational use of computer games during working hours.

PubMed

Reinecke, Leonard

2009-08-01

The present study investigated the recreational use of video and computer games in the workplace. In an online survey, 833 employed users of online casual games reported on their use of computer games during working hours. The data indicate that playing computer games in the workplace elicits substantial levels of recovery experience. Recovery experience associated with gameplay was the strongest predictor for the use of games in the workplace. Furthermore, individuals with higher levels of work-related fatigue reported stronger recovery experience during gameplay and showed a higher tendency to play games during working hours than did persons with lower levels of work strain. Additionally, the social situation at work was found to have a significant influence on the use of games. Persons receiving less social support from colleagues and supervisors played games at work more frequently than did individuals with higher levels of social support. Furthermore, job control was positively related to the use of games at work. In sum, the results of the present study illustrate that computer games have a significant recovery potential. Implications of these findings for research on personal computer use during work and for games research in general are discussed.

Learning to Interact with a Computer by Gaze

ERIC Educational Resources Information Center

Aoki, Hirotaka; Hansen, John Paulin; Itoh, Kenji

2008-01-01

The aim of this paper is to examine the learning processes that subjects undertake when they start using gaze as computer input. A 7-day experiment with eight Japanese students was carried out to record novice users' eye movement data during typing of 110 sentences. The experiment revealed that inefficient eye movements was dramatically reduced…

Experiences of Computer Science Curriculum Design: A Phenomenological Study

ERIC Educational Resources Information Center

Sloan, Arthur; Bowe, Brian

2015-01-01

This paper presents a qualitative study of 12 computer science lecturers' experiences of curriculum design of several degree programmes during a time of transition from year-long to semesterised courses, due to institutional policy change. The background to the study is outlined, as are the reasons for choosing the research methodology. The main…

The Development and Deployment of a Virtual Unit Operations Laboratory

ERIC Educational Resources Information Center

Vaidyanath, Sreeram; Williams, Jason; Hilliard, Marcus; Wiesner, Theodore

2007-01-01

Computer-simulated experiments offer many benefits to engineering curricula in the areas of safety, cost, and flexibility. We report our experience in developing and deploying a computer-simulated unit operations laboratory, driven by the guiding principle of maximum fidelity to the physical lab. We find that, while the up-front investment in…

Computer Simulations: An Integrating Tool.

ERIC Educational Resources Information Center

Bilan, Bohdan J.

This introduction to computer simulations as an integrated learning experience reports on their use with students in grades 5 through 10 using commercial software packages such as SimCity, SimAnt, SimEarth, and Civilization. Students spent an average of 60 hours with the simulation games and reported their experiences each week in a personal log.…

Group Theory, Computational Thinking, and Young Mathematicians

ERIC Educational Resources Information Center

Gadanidis, George; Clements, Erin; Yiu, Chris

2018-01-01

In this article, we investigate the artistic puzzle of designing mathematics experiences (MEs) to engage young children with ideas of group theory, using a combination of hands-on and computational thinking (CT) tools. We elaborate on: (1) group theory and why we chose it as a context for young mathematicians' experiences with symmetry and…

How to Augment the Learning Impact of Computer Simulations? The Designs and Effects of Interactivity and Scaffolding

ERIC Educational Resources Information Center

Chang, Hsin-Yi

2017-01-01

Two investigations were conducted in this study. In the first experiment, the effects of two types of interactivity with a computer simulation were compared: experimentation versus observation interactivity. Experimentation interactivity allows students to use simulations to conduct virtual experiments, whereas observation interactivity allows…

Using Computer-Based "Experiments" in the Analysis of Chemical Reaction Equilibria

ERIC Educational Resources Information Center

Li, Zhao; Corti, David S.

2018-01-01

The application of the Reaction Monte Carlo (RxMC) algorithm to standard textbook problems in chemical reaction equilibria is discussed. The RxMC method is a molecular simulation algorithm for studying the equilibrium properties of reactive systems, and therefore provides the opportunity to develop computer-based "experiments" for the…

Predictors of Creative Computing Participation and Profiles of Experience in Two Silicon Valley Middle Schools

ERIC Educational Resources Information Center

Barron, Brigid; Walter, Sarah E.; Martin, Caitlin Kennedy; Schatz, Colin

2010-01-01

Examination of the "digital divide" has increasingly gone beyond the study of differences in physical access to computers to focus on individuals' use of technological tools for empowered and generative uses. In this research study, we investigated the relationship between access to tools and experience with creative production…

DoE Early Career Research Program: Final Report: Model-Independent Dark-Matter Searches at the ATLAS Experiment and Applications of Many-core Computing to High Energy Physics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Farbin, Amir

2015-07-15

This is the final report of for DoE Early Career Research Program Grant Titled "Model-Independent Dark-Matter Searches at the ATLAS Experiment and Applications of Many-core Computing to High Energy Physics".

Photochemistry of Naphthopyrans and Derivatives: A Computational Experiment for Upper-Level Undergraduates or Graduate Students

ERIC Educational Resources Information Center

Castet, Frédéric; Méreau, Raphaël; Liotard, Daniel

2014-01-01

In this computational experiment, students use advanced quantum chemistry tools to simulate the photochromic reaction mechanism in naphthopyran derivatives. The first part aims to make students familiar with excited-state reaction mechanisms and addresses the photoisomerization of the benzopyran molecule by means of semiempirical quantum chemical…

The Students' Experiences of Ethics in Online Systems: A Phenomenological Study

ERIC Educational Resources Information Center

Mosalanejad, Leili; Dehghani, Ali; Abdolahifard, Khadije

2014-01-01

Cyber ethics is the philosophical study of ethics pertaining to computer networks encompassing users' behavior, what networked computers are programmed to do, and how this affects the individuals and the society. This study aimed to investigate the students' experiences of ethics in cyber systems.In the present study, the researchers conducted…

The Design and Evaluation of Teaching Experiments in Computer Science.

ERIC Educational Resources Information Center

Forcheri, Paola; Molfino, Maria Teresa

1992-01-01

Describes a relational model that was developed to provide a framework for the design and evaluation of teaching experiments for the introduction of computer science in secondary schools in Italy. Teacher training is discussed, instructional materials are considered, and use of the model for the evaluation process is described. (eight references)…

Gender Differences in Preschool Children's Recall of Competitive and Noncompetitive Computer Mathematics Games

ERIC Educational Resources Information Center

Wei, Fang-Yi Flora; Hendrix, Katherine Grace

2009-01-01

This study investigated whether competitive and noncompetitive educational mathematics computer games influence four- to seven-year-old boys' and girls' recall of game-playing experience. A qualitative analysis was performed to investigate what preschool children may have learned through their selective recall of game-playing experience. A…

A Review of Computer Simulations in Teacher Education

ERIC Educational Resources Information Center

Bradley, Elizabeth Gates; Kendall, Brittany

2014-01-01

Computer simulations can provide guided practice for a variety of situations that pre-service teachers would not frequently experience during their teacher education studies. Pre-service teachers can use simulations to turn the knowledge they have gained in their coursework into real experience. Teacher simulation training has come a long way over…

Displaying Special Characters and Symbols in Computer-Controlled Reaction Time Experiments.

ERIC Educational Resources Information Center

Friel, Brian M.; Kennison, Shelia M.

A procedure for using MEL2 (Version 2.0 of Microcomputer Experimental Laboratory) and FontWINDOW to present special characters and symbols in computer-controlled reaction time experiments is described. The procedure permits more convenience and flexibility than in tachistocopic and projection techniques. FontWINDOW allows researchers to design…

Numerical simulation of NQR/NMR: Applications in quantum computing.

PubMed

Possa, Denimar; Gaudio, Anderson C; Freitas, Jair C C

2011-04-01

A numerical simulation program able to simulate nuclear quadrupole resonance (NQR) as well as nuclear magnetic resonance (NMR) experiments is presented, written using the Mathematica package, aiming especially applications in quantum computing. The program makes use of the interaction picture to compute the effect of the relevant nuclear spin interactions, without any assumption about the relative size of each interaction. This makes the program flexible and versatile, being useful in a wide range of experimental situations, going from NQR (at zero or under small applied magnetic field) to high-field NMR experiments. Some conditions specifically required for quantum computing applications are implemented in the program, such as the possibility of use of elliptically polarized radiofrequency and the inclusion of first- and second-order terms in the average Hamiltonian expansion. A number of examples dealing with simple NQR and quadrupole-perturbed NMR experiments are presented, along with the proposal of experiments to create quantum pseudopure states and logic gates using NQR. The program and the various application examples are freely available through the link http://www.profanderson.net/files/nmr_nqr.php. Copyright © 2011 Elsevier Inc. All rights reserved.

Multi-Scale Modeling to Improve Single-Molecule, Single-Cell Experiments

NASA Astrophysics Data System (ADS)

Munsky, Brian; Shepherd, Douglas

2014-03-01

Single-cell, single-molecule experiments are producing an unprecedented amount of data to capture the dynamics of biological systems. When integrated with computational models, observations of spatial, temporal and stochastic fluctuations can yield powerful quantitative insight. We concentrate on experiments that localize and count individual molecules of mRNA. These high precision experiments have large imaging and computational processing costs, and we explore how improved computational analyses can dramatically reduce overall data requirements. In particular, we show how analyses of spatial, temporal and stochastic fluctuations can significantly enhance parameter estimation results for small, noisy data sets. We also show how full probability distribution analyses can constrain parameters with far less data than bulk analyses or statistical moment closures. Finally, we discuss how a systematic modeling progression from simple to more complex analyses can reduce total computational costs by orders of magnitude. We illustrate our approach using single-molecule, spatial mRNA measurements of Interleukin 1-alpha mRNA induction in human THP1 cells following stimulation. Our approach could improve the effectiveness of single-molecule gene regulation analyses for many other process.

Numerical simulations of the flow with the prescribed displacement of the airfoil and comparison with experiment

NASA Astrophysics Data System (ADS)

Řidký, V.; Šidlof, P.; Vlček, V.

2013-04-01

The work is devoted to comparing measured data with the results of numerical simulations. As mathematical model was used mathematical model whitout turbulence for incompressible flow In the experiment was observed the behavior of designed NACA0015 airfoil in airflow. For the numerical solution was used OpenFOAM computational package, this is open-source software based on finite volume method. In the numerical solution is prescribed displacement of the airfoil, which corresponds to the experiment. The velocity at a point close to the airfoil surface is compared with the experimental data obtained from interferographic measurements of the velocity field. Numerical solution is computed on a 3D mesh composed of about 1 million ortogonal hexahedron elements. The time step is limited by the Courant number. Parallel computations are run on supercomputers of the CIV at Technical University in Prague (HAL and FOX) and on a computer cluster of the Faculty of Mechatronics of Liberec (HYDRA). Run time is fixed at five periods, the results from the fifth periods and average value for all periods are then be compared with experiment.

Turn Teachers into Techies with "Computers to Go."

ERIC Educational Resources Information Center

Lare, Douglas

1991-01-01

Because unskilled teachers are unlikely to promote effective educational use of computers, the Catasauqua (Pennsylvania) Area School District compensates its teachers for computer training and provides them with computers for home use. The nonsalary cost of this successful program, modeled after Kirkland, Washington's experience, is less than…

Computer Self-Efficacy, Computer Anxiety, Performance and Personal Outcomes of Turkish Physical Education Teachers

ERIC Educational Resources Information Center

Aktag, Isil

2015-01-01

The purpose of this study is to determine the computer self-efficacy, performance outcome, personal outcome, and affect and anxiety level of physical education teachers. Influence of teaching experience, computer usage and participation of seminars or in-service programs on computer self-efficacy level were determined. The subjects of this study…

An Examination of How a Cross-Section of Academics Use Computer Technology when Writing Academic Papers.

ERIC Educational Resources Information Center

Wood, Eileen; Willoughby, Teena; Specht, Jacqueline; Porter, Lisa

2002-01-01

Describes a study conducted at two Canadian universities that surveyed a cross-section of 361 faculty, graduate, and undergraduate students to assess computer availability, experience, attitudes toward computers, and use of computers while engaged in academic writing. Compares advantages and disadvantages of writing on a computer versus written,…

The Impact of Primary School Teachers' Educational Beliefs on the Classroom Use of Computers

ERIC Educational Resources Information Center

Hermans, R.; Tondeur, J.; van Braak, J.; Valcke, M.

2008-01-01

For many years, researchers have searched for the factors affecting the use of computers in the classroom. In studying the antecedents of educational computer use, many studies adopt a rather limited view because only technology-related variables, such as attitudes to computers and computer experience were taken into account. The present study…

Setting Up a Grid-CERT: Experiences of an Academic CSIRT

ERIC Educational Resources Information Center

Moller, Klaus

2007-01-01

Purpose: Grid computing has often been heralded as the next logical step after the worldwide web. Users of grids can access dynamic resources such as computer storage and use the computing resources of computers under the umbrella of a virtual organisation. Although grid computing is often compared to the worldwide web, it is vastly more complex…

Goals and Objectives for Computing in the Associated Colleges of the St. Lawrence Valley.

ERIC Educational Resources Information Center

Grupe, Fritz H.

A forecast of the computing requirements of the Associated Colleges of the St. Lawrence Valley, an analysis of their needs, and specifications for a joint computer system are presented. Problems encountered included the lack of resources and computer sophistication at the member schools and a dearth of experience with long-term computer consortium…

High resolution frequency analysis techniques with application to the redshift experiment

NASA Technical Reports Server (NTRS)

Decher, R.; Teuber, D.

1975-01-01

High resolution frequency analysis methods, with application to the gravitational probe redshift experiment, are discussed. For this experiment a resolution of .00001 Hz is required to measure a slowly varying, low frequency signal of approximately 1 Hz. Major building blocks include fast Fourier transform, discrete Fourier transform, Lagrange interpolation, golden section search, and adaptive matched filter technique. Accuracy, resolution, and computer effort of these methods are investigated, including test runs on an IBM 360/65 computer.

Numerical Optimization Using Computer Experiments

NASA Technical Reports Server (NTRS)

Trosset, Michael W.; Torczon, Virginia

1997-01-01

Engineering design optimization often gives rise to problems in which expensive objective functions are minimized by derivative-free methods. We propose a method for solving such problems that synthesizes ideas from the numerical optimization and computer experiment literatures. Our approach relies on kriging known function values to construct a sequence of surrogate models of the objective function that are used to guide a grid search for a minimizer. Results from numerical experiments on a standard test problem are presented.

Science Notes.

ERIC Educational Resources Information Center

School Science Review, 1985

1985-01-01

Presents biology, chemistry, physics, and health activities, experiments, demonstrations, and computer programs. Includes mechanism of stomatal opening, using aquatic plants to help demonstrate chemical buffering, microbial activity/contamination in milk samples, computer computation of fitness scores, reservoir project, complexes of transition…

Computer-assisted Crystallization.

ERIC Educational Resources Information Center

Semeister, Joseph J., Jr.; Dowden, Edward

1989-01-01

To avoid a tedious task for recording temperature, a computer was used for calculating the heat of crystallization for the compound sodium thiosulfate. Described are the computer-interfacing procedures. Provides pictures of laboratory equipment and typical graphs from experiments. (YP)

Low-Budget Computer Programming in Your School (An Alternative to the Cost of Large Computers). Illinois Series on Educational Applications of Computers. No. 14.

ERIC Educational Resources Information Center

Dennis, J. Richard; Thomson, David

This paper is concerned with a low cost alternative for providing computer experience to secondary school students. The brief discussion covers the programmable calculator and its relevance for teaching the concepts and the rudiments of computer programming and for computer problem solving. A list of twenty-five programming activities related to…

Computational techniques to enable visualizing shapes of objects of extra spatial dimensions

NASA Astrophysics Data System (ADS)

Black, Don Vaughn, II

Envisioning extra dimensions beyond the three of common experience is a daunting challenge for three dimensional observers. Intuition relies on experience gained in a three dimensional environment. Gaining experience with virtual four dimensional objects and virtual three manifolds in four-space on a personal computer may provide the basis for an intuitive grasp of four dimensions. In order to enable such a capability for ourselves, it is first necessary to devise and implement a computationally tractable method to visualize, explore, and manipulate objects of dimension beyond three on the personal computer. A technology is described in this dissertation to convert a representation of higher dimensional models into a format that may be displayed in realtime on graphics cards available on many off-the-shelf personal computers. As a result, an opportunity has been created to experience the shape of four dimensional objects on the desktop computer. The ultimate goal has been to provide the user a tangible and memorable experience with mathematical models of four dimensional objects such that the user can see the model from any user selected vantage point. By use of a 4D GUI, an arbitrary convex hull or 3D silhouette of the 4D model can be rotated, panned, scrolled, and zoomed until a suitable dimensionally reduced view or Aspect is obtained. The 4D GUI then allows the user to manipulate a 3-flat hyperplane cutting tool to slice the model at an arbitrary orientation and position to extract or "pluck" an embedded 3D slice or "aspect" from the embedding four-space. This plucked 3D aspect can be viewed from all angles via a conventional 3D viewer using three multiple POV viewports, and optionally exported to a third party CAD viewer for further manipulation. Plucking and Manipulating the Aspect provides a tangible experience for the end-user in the same manner as any 3D Computer Aided Design viewing and manipulation tool does for the engineer or a 3D video game provides for the nascent student.

Processing LHC data in the UK

PubMed Central

Colling, D.; Britton, D.; Gordon, J.; Lloyd, S.; Doyle, A.; Gronbech, P.; Coles, J.; Sansum, A.; Patrick, G.; Jones, R.; Middleton, R.; Kelsey, D.; Cass, A.; Geddes, N.; Clark, P.; Barnby, L.

2013-01-01

The Large Hadron Collider (LHC) is one of the greatest scientific endeavours to date. The construction of the collider itself and the experiments that collect data from it represent a huge investment, both financially and in terms of human effort, in our hope to understand the way the Universe works at a deeper level. Yet the volumes of data produced are so large that they cannot be analysed at any single computing centre. Instead, the experiments have all adopted distributed computing models based on the LHC Computing Grid. Without the correct functioning of this grid infrastructure the experiments would not be able to understand the data that they have collected. Within the UK, the Grid infrastructure needed by the experiments is provided by the GridPP project. We report on the operations, performance and contributions made to the experiments by the GridPP project during the years of 2010 and 2011—the first two significant years of the running of the LHC. PMID:23230163

Pharmacist Computer Skills and Needs Assessment Survey

PubMed Central

Jewesson, Peter J

2004-01-01

Background To use technology effectively for the advancement of patient care, pharmacists must possess a variety of computer skills. We recently introduced a novel applied informatics program in this Canadian hospital clinical service unit to enhance the informatics skills of our members. Objective This study was conducted to gain a better understanding of the baseline computer skills and needs of our hospital pharmacists immediately prior to the implementation of an applied informatics program. Methods In May 2001, an 84-question written survey was distributed by mail to 106 practicing hospital pharmacists in our multi-site, 1500-bed, acute-adult-tertiary care Canadian teaching hospital in Vancouver, British Columbia. Results Fifty-eight surveys (55% of total) were returned within the two-week study period. The survey responses reflected the opinions of licensed BSc and PharmD hospital pharmacists with a broad range of pharmacy practice experience. Most respondents had home access to personal computers, and regularly used computers in the work environment for drug distribution, information management, and communication purposes. Few respondents reported experience with handheld computers. Software use experience varied according to application. Although patient-care information software and e-mail were commonly used, experience with spreadsheet, statistical, and presentation software was negligible. The respondents were familiar with Internet search engines, and these were reported to be the most common method of seeking clinical information online. Although many respondents rated themselves as being generally computer literate and not particularly anxious about using computers, the majority believed they required more training to reach their desired level of computer literacy. Lack of familiarity with computer-related terms was prevalent. Self-reported basic computer skill was typically at a moderate level, and varied depending on the task. Specifically, respondents rated their ability to manipulate files, use software help features, and install software as low, but rated their ability to access and navigate the Internet as high. Respondents were generally aware of what online resources were available to them and Clinical Pharmacology was the most commonly employed reference. In terms of anticipated needs, most pharmacists believed they needed to upgrade their computer skills. Medical database and Internet searching skills were identified as those in greatest need of improvement. Conclusions Most pharmacists believed they needed to upgrade their computer skills. Medical database and Internet searching skills were identified as those in greatest need of improvement for the purposes of improving practice effectiveness. PMID:15111277

Integration Of PanDA Workload Management System With Supercomputers for ATLAS and Data Intensive Science

DOE Office of Scientific and Technical Information (OSTI.GOV)

De, K; Jha, S; Klimentov, A

2016-01-01

The Large Hadron Collider (LHC), operating at the international CERN Laboratory in Geneva, Switzerland, is leading Big Data driven scientific explorations. Experiments at the LHC explore the fundamental nature of matter and the basic forces that shape our universe, and were recently credited for the discovery of a Higgs boson. ATLAS, one of the largest collaborations ever assembled in the sciences, is at the forefront of research at the LHC. To address an unprecedented multi-petabyte data processing challenge, the ATLAS experiment is relying on a heterogeneous distributed computational infrastructure. The ATLAS experiment uses PanDA (Production and Data Analysis) Workload Managementmore » System for managing the workflow for all data processing on over 150 data centers. Through PanDA, ATLAS physicists see a single computing facility that enables rapid scientific breakthroughs for the experiment, even though the data centers are physically scattered all over the world. While PanDA currently uses more than 250,000 cores with a peak performance of 0.3 petaFLOPS, LHC data taking runs require more resources than Grid computing can possibly provide. To alleviate these challenges, LHC experiments are engaged in an ambitious program to expand the current computing model to include additional resources such as the opportunistic use of supercomputers. We will describe a project aimed at integration of PanDA WMS with supercomputers in United States, Europe and Russia (in particular with Titan supercomputer at Oak Ridge Leadership Computing Facility (OLCF), MIRA supercomputer at Argonne Leadership Computing Facilities (ALCF), Supercomputer at the National Research Center Kurchatov Institute , IT4 in Ostrava and others). Current approach utilizes modified PanDA pilot framework for job submission to the supercomputers batch queues and local data management, with light-weight MPI wrappers to run single threaded workloads in parallel on LCFs multi-core worker nodes. This implementation was tested with a variety of Monte-Carlo workloads on several supercomputing platforms for ALICE and ATLAS experiments and it is in full production for the ATLAS experiment since September 2015. We will present our current accomplishments with running PanDA WMS at supercomputers and demonstrate our ability to use PanDA as a portal independent of the computing facilities infrastructure for High Energy and Nuclear Physics as well as other data-intensive science applications, such as bioinformatics and astro-particle physics.« less

Use of Tablet Computers to Promote Physical Therapy Students' Engagement in Knowledge Translation During Clinical Experiences

PubMed Central

Loeb, Kathryn; Barbosa, Sabrina; Jiang, Fei; Lee, Karin T.

2016-01-01

Background and Purpose: Physical therapists strive to integrate research into daily practice. The tablet computer is a potentially transformational tool for accessing information within the clinical practice environment. The purpose of this study was to measure and describe patterns of tablet computer use among physical therapy students during clinical rotation experiences. Methods: Doctor of physical therapy students (n = 13 users) tracked their use of tablet computers (iPad), loaded with commercially available apps, during 16 clinical experiences (6-16 weeks in duration). Results: The tablets were used on 70% of 691 clinic days, averaging 1.3 uses per day. Information seeking represented 48% of uses; 33% of those were foreground searches for research articles and syntheses and 66% were for background medical information. Other common uses included patient education (19%), medical record documentation (13%), and professional communication (9%). The most frequently used app was Safari, the preloaded web browser (representing 281 [36.5%] incidents of use). Users accessed 56 total apps to support clinical practice. Discussion and Conclusions: Physical therapy students successfully integrated use of a tablet computer into their clinical experiences including regular activities of information seeking. Our findings suggest that the tablet computer represents a potentially transformational tool for promoting knowledge translation in the clinical practice environment. Video Abstract available for more insights from the authors (see Supplemental Digital Content 1, http://links.lww.com/JNPT/A127). PMID:26945431

PanDA: Exascale Federation of Resources for the ATLAS Experiment at the LHC

NASA Astrophysics Data System (ADS)

Barreiro Megino, Fernando; Caballero Bejar, Jose; De, Kaushik; Hover, John; Klimentov, Alexei; Maeno, Tadashi; Nilsson, Paul; Oleynik, Danila; Padolski, Siarhei; Panitkin, Sergey; Petrosyan, Artem; Wenaus, Torre

2016-02-01

After a scheduled maintenance and upgrade period, the world's largest and most powerful machine - the Large Hadron Collider(LHC) - is about to enter its second run at unprecedented energies. In order to exploit the scientific potential of the machine, the experiments at the LHC face computational challenges with enormous data volumes that need to be analysed by thousand of physics users and compared to simulated data. Given diverse funding constraints, the computational resources for the LHC have been deployed in a worldwide mesh of data centres, connected to each other through Grid technologies. The PanDA (Production and Distributed Analysis) system was developed in 2005 for the ATLAS experiment on top of this heterogeneous infrastructure to seamlessly integrate the computational resources and give the users the feeling of a unique system. Since its origins, PanDA has evolved together with upcoming computing paradigms in and outside HEP, such as changes in the networking model, Cloud Computing and HPC. It is currently running steadily up to 200 thousand simultaneous cores (limited by the available resources for ATLAS), up to two million aggregated jobs per day and processes over an exabyte of data per year. The success of PanDA in ATLAS is triggering the widespread adoption and testing by other experiments. In this contribution we will give an overview of the PanDA components and focus on the new features and upcoming challenges that are relevant to the next decade of distributed computing workload management using PanDA.

78 FR 54453 - Notice of Public Meeting-Intersection of Cloud Computing and Mobility Forum and Workshop

Federal Register 2010, 2011, 2012, 2013, 2014

2013-09-04

...--Intersection of Cloud Computing and Mobility Forum and Workshop AGENCY: National Institute of Standards and.../intersection-of-cloud-and-mobility.cfm . SUPPLEMENTARY INFORMATION: NIST hosted six prior Cloud Computing Forum... interoperability, portability, and security, discuss the Federal Government's experience with cloud computing...

Computers in Spaceflight: the NASA Experience

NASA Technical Reports Server (NTRS)

Tomayko, James E.

1988-01-01

This book examines the computer systems used in actual spaceflight or in close support of it. Each chapter deals with either a specific program, such as Gemini or Apollo onboard computers, or a closely related set of systems, such as launch processing or mission control. A glossary of computer terms is included.

Project-Based Teaching-Learning Computer-Aided Engineering Tools

ERIC Educational Resources Information Center

Simoes, J. A.; Relvas, C.; Moreira, R.

2004-01-01

Computer-aided design, computer-aided manufacturing, computer-aided analysis, reverse engineering and rapid prototyping are tools that play an important key role within product design. These are areas of technical knowledge that must be part of engineering and industrial design courses' curricula. This paper describes our teaching experience of…

Jack Rabbit Pretest Data For TATB Based IHE Model Development

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hart, M M; Strand, O T; Bosson, S T

The Jack Rabbit Pretest series consisted of 5 focused hydrodynamic experiments, 2021E PT3, PT4, PT5, PT6, and PT7. They were fired in March and April of 2008 at the Contained Firing Facility, Site 300, Lawrence Livermore National Laboratory, Livermore, California. These experiments measured dead-zone formation and impulse gradients created during the detonation of TATB based insensitive high explosive. This document contains reference data tables for all 5 experiments. These data tables include: (1) Measured laser velocimetry of the experiment diagnostic plate (2) Computed diagnostic plate profile contours through velocity integration (3) Computed center axis pressures through velocity differentiation. All timesmore » are in microseconds, referenced from detonator circuit current start. All dimensions are in millimeters. Schematic axi-symmetric cross sections are shown for each experiment. These schematics detail the materials used and dimensions of the experiment and component parts. This should allow anyone wanting to evaluate their TATB based insensitive high explosive detonation model against experiment. These data are particularly relevant in examining reactive flow detonation model prediction in computational simulation of dead-zone formation and resulting impulse gradients produced by detonating TATB based explosive.« less

Challenges in scaling NLO generators to leadership computers

NASA Astrophysics Data System (ADS)

Benjamin, D.; Childers, JT; Hoeche, S.; LeCompte, T.; Uram, T.

2017-10-01

Exascale computing resources are roughly a decade away and will be capable of 100 times more computing than current supercomputers. In the last year, Energy Frontier experiments crossed a milestone of 100 million core-hours used at the Argonne Leadership Computing Facility, Oak Ridge Leadership Computing Facility, and NERSC. The Fortran-based leading-order parton generator called Alpgen was successfully scaled to millions of threads to achieve this level of usage on Mira. Sherpa and MadGraph are next-to-leading order generators used heavily by LHC experiments for simulation. Integration times for high-multiplicity or rare processes can take a week or more on standard Grid machines, even using all 16-cores. We will describe our ongoing work to scale the Sherpa generator to thousands of threads on leadership-class machines and reduce run-times to less than a day. This work allows the experiments to leverage large-scale parallel supercomputers for event generation today, freeing tens of millions of grid hours for other work, and paving the way for future applications (simulation, reconstruction) on these and future supercomputers.

Flow and Turbulence Modeling and Computation of Shock Buffet Onset for Conventional and Supercritical Airfoils

NASA Technical Reports Server (NTRS)

Bartels, Robert E.

1998-01-01

Flow and turbulence models applied to the problem of shock buffet onset are studied. The accuracy of the interactive boundary layer and the thin-layer Navier-Stokes equations solved with recent upwind techniques using similar transport field equation turbulence models is assessed for standard steady test cases, including conditions having significant shock separation. The two methods are found to compare well in the shock buffet onset region of a supercritical airfoil that involves strong trailing-edge separation. A computational analysis using the interactive-boundary layer has revealed a Reynolds scaling effect in the shock buffet onset of the supercritical airfoil, which compares well with experiment. The methods are next applied to a conventional airfoil. Steady shock-separated computations of the conventional airfoil with the two methods compare well with experiment. Although the interactive boundary layer computations in the shock buffet region compare well with experiment for the conventional airfoil, the thin-layer Navier-Stokes computations do not. These findings are discussed in connection with possible mechanisms important in the onset of shock buffet and the constraints imposed by current numerical modeling techniques.

Practicality in Virtuality: Finding Student Meaning in Video Game Education

NASA Astrophysics Data System (ADS)

Barko, Timothy; Sadler, Troy D.

2013-04-01

This paper looks at the conceptual differences between video game learning and traditional classroom and laboratory learning. It explores the notion of virtual experience by comparing a commonly used high school laboratory protocol on DNA extraction with a similar experience provided by a biotechnology themed video game. When considered conceptually, the notion of virtual experience is not limited to those experiences generated by computer aided technology, as with a video game or computer simulation. The notion of virtuality can apply to many real world experiences as well. It is proposed that the medium of the learning experience, be it video game or classroom, is not an important distinction to consider; instead, we should seek to determine what kinds of meaningful experiences apply for both classrooms and video games.

Computational Investigation of the Performance and Back-Pressure Limits of a Hypersonic Inlet

NASA Technical Reports Server (NTRS)

Smart, Michael K.; White, Jeffery A.

2002-01-01

A computational analysis of Mach 6.2 operation of a hypersonic inlet with rectangular-to-elliptical shape transition has been performed. The results of the computations are compared with experimental data for cases with and without a manually imposed back-pressure. While the no-back-pressure numerical solutions match the general trends of the data, certain features observed in the experiments did not appear in the computational solutions. The reasons for these discrepancies are discussed and possible remedies are suggested. Most importantly, however, the computational analysis increased the understanding of the consequences of certain aspects of the inlet design. This will enable the performance of future inlets of this class to be improved. Computational solutions with back-pressure under-estimated the back-pressure limit observed in the experiments, but did supply significant insight into the character of highly back-pressured inlet flows.

Computational Experiments for Science and Engineering Education

NASA Technical Reports Server (NTRS)

Xie, Charles

2011-01-01

How to integrate simulation-based engineering and science (SBES) into the science curriculum smoothly is a challenging question. For the importance of SBES to be appreciated, the core value of simulations-that they help people understand natural phenomena and solve engineering problems-must be taught. A strategy to achieve this goal is to introduce computational experiments to the science curriculum to replace or supplement textbook illustrations and exercises and to complement or frame hands-on or wet lab experiments. In this way, students will have an opportunity to learn about SBES without compromising other learning goals required by the standards and teachers will welcome these tools as they strengthen what they are already teaching. This paper demonstrates this idea using a number of examples in physics, chemistry, and engineering. These exemplary computational experiments show that it is possible to create a curriculum that is both deeper and wider.

GSDC: A Unique Data Center in Korea for HEP research

NASA Astrophysics Data System (ADS)

Ahn, Sang-Un

2017-04-01

Global Science experimental Data hub Center (GSDC) at Korea Institute of Science and Technology Information (KISTI) is a unique data center in South Korea established for promoting the fundamental research fields by supporting them with the expertise on Information and Communication Technology (ICT) and the infrastructure for High Performance Computing (HPC), High Throughput Computing (HTC) and Networking. GSDC has supported various research fields in South Korea dealing with the large scale of data, e.g. RENO experiment for neutrino research, LIGO experiment for gravitational wave detection, Genome sequencing project for bio-medical, and HEP experiments such as CDF at FNAL, Belle at KEK, and STAR at BNL. In particular, GSDC has run a Tier-1 center for ALICE experiment using the LHC at CERN since 2013. In this talk, we present the overview on computing infrastructure that GSDC runs for the research fields and we discuss on the data center infrastructure management system deployed at GSDC.

Statistical Methodologies to Integrate Experimental and Computational Research

NASA Technical Reports Server (NTRS)

Parker, P. A.; Johnson, R. T.; Montgomery, D. C.

2008-01-01

Development of advanced algorithms for simulating engine flow paths requires the integration of fundamental experiments with the validation of enhanced mathematical models. In this paper, we provide an overview of statistical methods to strategically and efficiently conduct experiments and computational model refinement. Moreover, the integration of experimental and computational research efforts is emphasized. With a statistical engineering perspective, scientific and engineering expertise is combined with statistical sciences to gain deeper insights into experimental phenomenon and code development performance; supporting the overall research objectives. The particular statistical methods discussed are design of experiments, response surface methodology, and uncertainty analysis and planning. Their application is illustrated with a coaxial free jet experiment and a turbulence model refinement investigation. Our goal is to provide an overview, focusing on concepts rather than practice, to demonstrate the benefits of using statistical methods in research and development, thereby encouraging their broader and more systematic application.

Separating Added Value from Hype: Some Experiences and Prognostications

NASA Astrophysics Data System (ADS)

Reed, Dan

2004-03-01

These are exciting times for the interplay of science and computing technology. As new data archives, instruments and computing facilities are connected nationally and internationally, a new model of distributed scientific collaboration is emerging. However, any new technology brings both opportunities and challenges -- Grids are no exception. In this talk, we will discuss some of the experiences deploying Grid software in production environments, illustrated with experiences from the NSF PACI Alliance, the NSF Extensible Terascale Facility (ETF) and other Grid projects. From these experiences, we derive some guidelines for deployment and some suggestions for community engagement, software development and infrastructure

Use of a personal computer for the real-time reception and analysis of data from a sounding rocket experiment

NASA Technical Reports Server (NTRS)

Herrick, W. D.; Penegor, G. T.; Cotton, D. M.; Kaplan, G. C.; Chakrabarti, S.

1990-01-01

In September 1988 the Earth and Planetary Atmospheres Group of the Space Sciences Laboratory of the University of California at Berkeley flew an experiment on a high-altitude sounding rocket launched from the NASA Wallops Flight Facility in Virginia. The experiment, BEARS (Berkeley EUV Airglow Rocket Spectrometer), was designed to obtain spectroscopic data on the composition and structure of the earth's upper atmosphere. Consideration is given to the objectives of the BEARS experiment; the computer interface and software; the use of remote data transmission; and calibration, integration, and flight operations.

The digital computer as a metaphor for the perfect laboratory experiment: Loophole-free Bell experiments

NASA Astrophysics Data System (ADS)

De Raedt, Hans; Michielsen, Kristel; Hess, Karl

2016-12-01

Using Einstein-Podolsky-Rosen-Bohm experiments as an example, we demonstrate that the combination of a digital computer and algorithms, as a metaphor for a perfect laboratory experiment, provides solutions to problems of the foundations of physics. Employing discrete-event simulation, we present a counterexample to John Bell's remarkable "proof" that any theory of physics, which is both Einstein-local and "realistic" (counterfactually definite), results in a strong upper bound to the correlations that are being measured in Einstein-Podolsky-Rosen-Bohm experiments. Our counterexample, which is free of the so-called detection-, coincidence-, memory-, and contextuality loophole, violates this upper bound and fully agrees with the predictions of quantum theory for Einstein-Podolsky-Rosen-Bohm experiments.

Computer-Based Testing in the Medical Curriculum: A Decade of Experiences at One School

ERIC Educational Resources Information Center

McNulty, John; Chandrasekhar, Arcot; Hoyt, Amy; Gruener, Gregory; Espiritu, Baltazar; Price, Ron, Jr.

2011-01-01

This report summarizes more than a decade of experiences with implementing computer-based testing across a 4-year medical curriculum. Practical considerations are given to the fields incorporated within an item database and their use in the creation and analysis of examinations, security issues in the delivery and integrity of examinations,…

Technology Readiness, Internet Self-Efficacy and Computing Experience of Professional Accounting Students

ERIC Educational Resources Information Center

Lai, Ming-Ling

2008-01-01

Purpose: This study aims to assess the state of technology readiness of professional accounting students in Malaysia, to examine their level of internet self-efficacy, to assess their prior computing experience, and to explore if they are satisfied with the professional course that they are pursuing in improving their technology skills.…

Student Computer Attitudes, Experience and Perceptions about the Use of Two Software Applications in Building Engineering

ERIC Educational Resources Information Center

Chiner, Esther; Garcia-Vera, Victoria E.

2017-01-01

The purpose of this study was to examine students' computer attitudes and experience, as well as students' perceptions about the use of two specific software applications (Google Drive Spreadsheets and Arquimedes) in the Building Engineering context. The relationships among these variables were also examined. Ninety-two students took part in this…

Usnic Acid and the Intramolecular Hydrogen Bond: A Computational Experiment for the Organic Laboratory

ERIC Educational Resources Information Center

Green, Thomas K.; Lane, Charles A.

2006-01-01

A computational experiment is described for the organic chemistry laboratory that allows students to estimate the relative strengths of the intramolecular hydrogen bonds of usnic and isousnic acids, two related lichen secondary metabolites. Students first extract and purify usnic acid from common lichens and obtain [superscript 1]H NMR and IR…

Neural nets on the MPP

NASA Technical Reports Server (NTRS)

Hastings, Harold M.; Waner, Stefan

1987-01-01

The Massively Parallel Processor (MPP) is an ideal machine for computer experiments with simulated neural nets as well as more general cellular automata. Experiments using the MPP with a formal model neural network are described. The results on problem mapping and computational efficiency apply equally well to the neural nets of Hopfield, Hinton et al., and Geman and Geman.

Hidden Dangers of Computer Modelling: Remarks on Sokolik and Smith's Connectionist Learning Model of French Gender.

ERIC Educational Resources Information Center

Carroll, Susanne E.

1995-01-01

Criticizes the computer modelling experiments conducted by Sokolik and Smith (1992), which involved the learning of French gender attribution using connectionist architecture. The article argues that the experiments greatly oversimplified the complexity of gender learning, in that they were designed in such a way that knowledge that must be…

Some Principles for the Human Use of Computers in Education.

ERIC Educational Resources Information Center

Dwyer, Thomas A.

Several principles for the effective use of computers in education are identified as a result of experiences with Project Solo, an experiment in education patterned on the dual-solo example of flight instruction in allowing the student to eventually exert more influence on his learning than his instructor. First, the essential social character of…

Getting from x to y without Crashing: Computer Syntax in Mathematics Education

ERIC Educational Resources Information Center

Jeffrey, David J.

2010-01-01

When we use technology to teach mathematics, we hope to focus on the mathematics, restricting the computer software systems to providing support for our pedagogy. It is a matter of common experience, however, that students can become distracted or frustrated by the quirks of the particular software system being used. Here, experience using the…

Integrating IS Curriculum Knowledge through a Cluster-Computing Project--A Successful Experiment

ERIC Educational Resources Information Center

Kitchens, Fred L.; Sharma, Sushil K.; Harris, Thomas

2004-01-01

MIS curricula in business schools are challenged to provide MIS courses that give students a strong practical understanding of the basic technologies, while also providing enough hands-on experience to solve real life problems. As an experimental capstone MIS course, the authors developed a cluster-computing project to expose business students to…

Distinctive Features Hold a Privileged Status in the Computation of Word Meaning: Implications for Theories of Semantic Memory

ERIC Educational Resources Information Center

Cree, George S.; McNorgan, Chris; McRae, Ken

2006-01-01

The authors present data from 2 feature verification experiments designed to determine whether distinctive features have a privileged status in the computation of word meaning. They use an attractor-based connectionist model of semantic memory to derive predictions for the experiments. Contrary to central predictions of the conceptual structure…

Experiences in Evaluating Outcomes in Tool-Based, Competence Building Education in Dynamical Systems Using Symbolic Computer Algebra

ERIC Educational Resources Information Center

Perram, John W.; Andersen, Morten; Ellekilde, Lars-Peter; Hjorth, Poul G.

2004-01-01

This paper discusses experience with alternative assessment strategies for an introductory course in dynamical systems, where the use of computer algebra and calculus is fully integrated into the learning process, so that the standard written examination would not be appropriate. Instead, students' competence was assessed by grading three large…

Solution of the Schrodinger Equation for a Diatomic Oscillator Using Linear Algebra: An Undergraduate Computational Experiment

ERIC Educational Resources Information Center

Gasyna, Zbigniew L.

2008-01-01

Computational experiment is proposed in which a linear algebra method is applied to the solution of the Schrodinger equation for a diatomic oscillator. Calculations of the vibration-rotation spectrum for the HCl molecule are presented and the results show excellent agreement with experimental data. (Contains 1 table and 1 figure.)

ARC-2006-ACD06-0135-014

NASA Image and Video Library

2006-08-19

DC-8 NAMMA MISSION TO CAPE VERDE, AFRICA: Glenn Diskin (l) Bruce Anderson (c) & Ed Winstead (r) examine data on computer screens hooked up to two Langley Res. Ctr. experiments. The DLH (Diode Laser Hygometer) screen is on the left and one of the computer screens for the LARGE instrument package (Langley Aerosol Research Group Experiment) is on the right.

An Overview of Recent Developments in Computational Aeroelasticity

NASA Technical Reports Server (NTRS)

Bennett, Robert M.; Edwards, John W.

2004-01-01

The motivation for Computational Aeroelasticity (CA) and the elements of one type of the analysis or simulation process are briefly reviewed. The need for streamlining and improving the overall process to reduce elapsed time and improve overall accuracy is discussed. Further effort is needed to establish the credibility of the methodology, obtain experience, and to incorporate the experience base to simplify the method for future use. Experience with the application of a variety of Computational Aeroelasticity programs is summarized for the transonic flutter of two wings, the AGARD 445.6 wing and a typical business jet wing. There is a compelling need for a broad range of additional flutter test cases for further comparisons. Some existing data sets that may offer CA challenges are presented.

LASER APPLICATIONS AND OTHER TOPICS IN QUANTUM ELECTRONICS: Methods of computational physics in the problem of mathematical interpretation of laser investigations

NASA Astrophysics Data System (ADS)

Brodyn, M. S.; Starkov, V. N.

2007-07-01

It is shown that in laser experiments performed by using an 'imperfect' setup when instrumental distortions are considerable, sufficiently accurate results can be obtained by the modern methods of computational physics. It is found for the first time that a new instrumental function — the 'cap' function — a 'sister' of a Gaussian curve proved to be demanded namely in laser experiments. A new mathematical model of a measurement path and carefully performed computational experiment show that a light beam transmitted through a mesoporous film has actually a narrower intensity distribution than the detected beam, and the amplitude of the real intensity distribution is twice as large as that for measured intensity distributions.

Computer Self-Efficacy among Senior High School Teachers in Ghana and the Functionality of Demographic Variables on Their Computer Self-Efficacy

ERIC Educational Resources Information Center

Sarfo, Frederick Kwaku; Amankwah, Francis; Konin, Daniel

2017-01-01

The study is aimed at investigating 1) the level of computer self-efficacy among public senior high school (SHS) teachers in Ghana and 2) the functionality of teachers' age, gender, and computer experiences on their computer self-efficacy. Four hundred and Seven (407) SHS teachers were used for the study. The "Computer Self-Efficacy"…

Learning and teaching with a computer scanner

NASA Astrophysics Data System (ADS)

Planinsic, G.; Gregorcic, B.; Etkina, E.

2014-09-01

This paper introduces the readers to simple inquiry-based activities (experiments with supporting questions) that one can do with a computer scanner to help students learn and apply the concepts of relative motion in 1 and 2D, vibrational motion and the Doppler effect. We also show how to use these activities to help students think like scientists. They will conduct simple experiments, construct different explanations for their observations, test their explanations in new experiments and represent their ideas in multiple ways.

Outline of CS application experiments

NASA Astrophysics Data System (ADS)

Otsu, Y.; Kondoh, K.; Matsumoto, M.

1985-09-01

To promote and investigate the practical application of satellite use, CS application experiments for various social activity needs, including those of public services such as the National Police Agency and the Japanese National Railway, computer network services, news material transmissions, and advanced teleconference activities, were performed. Public service satellite communications systems were developed and tested. Based on results obtained, several public services have implemented CS-2 for practical disaster-back-up uses. Practical application computer network and enhanced video-conference experiments have also been performed.

Computational methods for fracture analysis of heavy-section steel technology (HSST) pressure vessel experiments

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bass, B.R.; Bryan, R.H.; Bryson, J.W.

This paper summarizes the capabilities and applications of the general-purpose and special-purpose computer programs that have been developed for use in fracture mechanics analyses of HSST pressure vessel experiments. Emphasis is placed on the OCA/USA code, which is designed for analysis of pressurized-thermal-shock (PTS) conditions, and on the ORMGEN/ADINA/ORVIRT system which is used for more general analysis. Fundamental features of these programs are discussed, along with applications to pressure vessel experiments.

CFD validation experiments at the Lockheed-Georgia Company

NASA Technical Reports Server (NTRS)

Malone, John B.; Thomas, Andrew S. W.

1987-01-01

Information is given in viewgraph form on computational fluid dynamics (CFD) validation experiments at the Lockheed-Georgia Company. Topics covered include validation experiments on a generic fighter configuration, a transport configuration, and a generic hypersonic vehicle configuration; computational procedures; surface and pressure measurements on wings; laser velocimeter measurements of a multi-element airfoil system; the flowfield around a stiffened airfoil; laser velocimeter surveys of a circulation control wing; circulation control for high lift; and high angle of attack aerodynamic evaluations.

Building Computer-Based Experiments in Psychology without Programming Skills.

PubMed

Ruisoto, Pablo; Bellido, Alberto; Ruiz, Javier; Juanes, Juan A

2016-06-01

Research in Psychology usually requires to build and run experiments. However, although this task has required scripting, recent computer tools based on graphical interfaces offer new opportunities in this field for researchers with non-programming skills. The purpose of this study is to illustrate and provide a comparative overview of two of the main free open source "point and click" software packages for building and running experiments in Psychology: PsychoPy and OpenSesame. Recommendations for their potential use are further discussed.

Parallel approach in RDF query processing

NASA Astrophysics Data System (ADS)

Vajgl, Marek; Parenica, Jan

2017-07-01

Parallel approach is nowadays a very cheap solution to increase computational power due to possibility of usage of multithreaded computational units. This hardware became typical part of nowadays personal computers or notebooks and is widely spread. This contribution deals with experiments how evaluation of computational complex algorithm of the inference over RDF data can be parallelized over graphical cards to decrease computational time.

The Utah Educational Technology Initiative Year Two Evaluation: Program Implementation, Computer Acquisition and Placement, and Computer Use.

ERIC Educational Resources Information Center

Mergendoller, John R.; And Others

This evaluation report describes program implementation, computer acquisition and placement, and computer use during the second year (1991-92) of the Utah Educational Technology Initiative (ETI). In addition, it discusses the various ways computers are used in Utah schools and reports the opinions and experiences of ETI coordinators in the 12…

A Longitudinal Investigation of the Effects of Computer Anxiety on Performance in a Computing-Intensive Environment

ERIC Educational Resources Information Center

Buche, Mari W.; Davis, Larry R.; Vician, Chelley

2007-01-01

Computers are pervasive in business and education, and it would be easy to assume that all individuals embrace technology. However, evidence shows that roughly 30 to 40 percent of individuals experience some level of computer anxiety. Many academic programs involve computing-intensive courses, but the actual effects of this exposure on computer…

Hubble Catches Stellar Exodus in Action

NASA Image and Video Library

2015-05-14

Using NASA’s Hubble Space Telescope, astronomers have captured for the first time snapshots of fledging white dwarf stars beginning their slow-paced, 40-million-year migration from the crowded center of an ancient star cluster to the less populated suburbs. White dwarfs are the burned-out relics of stars that rapidly lose mass, cool down and shut off their nuclear furnaces. As these glowing carcasses age and shed weight, their orbits begin to expand outward from the star cluster’s packed downtown. This migration is caused by a gravitational tussle among stars inside the cluster. Globular star clusters sort out stars according to their mass, governed by a gravitational billiard ball game where lower mass stars rob momentum from more massive stars. The result is that heavier stars slow down and sink to the cluster's core, while lighter stars pick up speed and move across the cluster to the edge. This process is known as "mass segregation." Until these Hubble observations, astronomers had never definitively seen the dynamical conveyor belt in action. Astronomers used Hubble to watch the white-dwarf exodus in the globular star cluster 47 Tucanae, a dense swarm of hundreds of thousands of stars in our Milky Way galaxy. The cluster resides 16,700 light-years away in the southern constellation Tucana. Credits: NASA, ESA, and H. Richer and J. Heyl (University of British Columbia, Vancouver, Canada); acknowledgement: J. Mack (STScI) and G. Piotto (University of Padova, Italy)

The Smallest Drops of the Hottest Matter? New Investigations at the Relativistic Heavy Ion Collider (493rd Brookhaven Lecture)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sickles, Anne

2014-03-19

Pool sharks at the billiards hall know that sometimes you aim to rocket the cue ball for a head-on collision, and other times, a mere glance will do. Physicists need to know more than a thing or two about collision geometry too, as they sift through data from the billions of ions that smash together at the Relativistic Heavy Ion Collider (RHIC). Determining whether ions crash head-on or just glance is crucial for the physicists analyzing data to study quark-gluon plasma—the ultra-hot, "perfect" liquid of quarks and gluons that existed more than 13 billion years ago, before the first protonsmore » and neutrons formed. For these physicists, collision geometry data provides insights about quark-gluon plasma's extremely low viscosity and other unusual properties, which are essential for understanding more about the "strong force" that holds together the nucleus, protons, and neutrons of every atom in the universe. Dr. Sickles explains how physicists use data collected at house-sized detectors like PHENIX and STAR to determine what happens before, during, and after individual particle collisions among billions at RHIC. She also explains how the ability to collide different "species" of nuclei at RHIC—including protons and gold ions today and possibly more with a proposed future electron-ion collider upgrade (eRHIC)—enables physicists to probe deeper into the mysteries of quark-gluon plasma and the strong force.« less

Application of SLURM, BOINC, and GlusterFS as Software System for Sustainable Modeling and Data Analytics

NASA Astrophysics Data System (ADS)

Kashansky, Vladislav V.; Kaftannikov, Igor L.

2018-02-01

Modern numerical modeling experiments and data analytics problems in various fields of science and technology reveal a wide variety of serious requirements for distributed computing systems. Many scientific computing projects sometimes exceed the available resource pool limits, requiring extra scalability and sustainability. In this paper we share the experience and findings of our own on combining the power of SLURM, BOINC and GlusterFS as software system for scientific computing. Especially, we suggest a complete architecture and highlight important aspects of systems integration.

AGIS: The ATLAS Grid Information System

NASA Astrophysics Data System (ADS)

Anisenkov, Alexey; Belov, Sergey; Di Girolamo, Alessandro; Gayazov, Stavro; Klimentov, Alexei; Oleynik, Danila; Senchenko, Alexander

2012-12-01

ATLAS is a particle physics experiment at the Large Hadron Collider at CERN. The experiment produces petabytes of data annually through simulation production and tens petabytes of data per year from the detector itself. The ATLAS Computing model embraces the Grid paradigm and a high degree of decentralization and computing resources able to meet ATLAS requirements of petabytes scale data operations. In this paper we present ATLAS Grid Information System (AGIS) designed to integrate configuration and status information about resources, services and topology of whole ATLAS Grid needed by ATLAS Distributed Computing applications and services.

MorphoHawk: Geometric-based Software for Manufacturing and More

DOE Office of Scientific and Technical Information (OSTI.GOV)

Keith Arterburn

2001-04-01

Hollywood movies portray facial recognition as a perfected technology, but reality is that sophisticated computers and algorithmic calculations are far from perfect. In fact, the most sophisticated and successful computer for recognizing faces and other imagery already is the human brain with more than 10 billion nerve cells. Beginning at birth, humans process data and connect optical and sensory experiences that create unparalleled accumulation of data for people to associate images with life experiences, emotions and knowledge. Computers are powerful, rapid and tireless, but still cannot compare to the highly sophisticated relational calculations and associations that the human computer canmore » produce in connecting ‘what we see with what we know.’« less

Computer aided field editing in the DHS context: the Turkey experiment.

PubMed

Cushing, J; Loaiza, E

1994-01-01

"In this study two types of field editing used during the Turkey Demographic and Health Survey are compared. These two types of editing are computer aided field editing and manual editing. It is known that manual editing by field editors is a tedious job in which errors especially on skip questions can be missed; however, with the aid of computers field editors could quickly find all occasions on which an interviewer incorrectly followed a skip instruction. At the end of the experiment it has been found...that the field editing done with the aid of a notebook computer was consistently better than that done in the standard manual manner." (SUMMARY IN TUR) excerpt

A Computer-Based Simulation of an Acid-Base Titration

ERIC Educational Resources Information Center

Boblick, John M.

1971-01-01

Reviews the advantages of computer simulated environments for experiments, referring in particular to acid-base titrations. Includes pre-lab instructions and a sample computer printout of a student's use of an acid-base simulation. Ten references. (PR)

Meeting the Educational and Therapeutic Needs of Short Term Hospitalized Children with the Aid of the Computer.

ERIC Educational Resources Information Center

Ciminero, Sandra Elser

The acute care pediatric/adolescent unit at Saint Joseph Hospital in Chicago, Illinois offers patients computer services consisting of recreation, general education, newspaper, and patient education components. To gather information concerning patients' experience with computers and to assess the effectiveness of computer services, data were…

ComputerTown. A Do-It-Yourself Community Computer Project.

ERIC Educational Resources Information Center

Loop, Liza; And Others

This manual based on Menlo Park's experiences in participating in a nationwide experimental computer literacy project provides guidelines for the development and management of a ComputerTown. This project, which was begun in September 1981 in the Menlo Park Public Library, concentrates on providing public access to microcomputers through hands-on…

Braving the Waters, or How To Get your Computing "Feet" Wet.

ERIC Educational Resources Information Center

Miller, Pat

1997-01-01

Suggests ways for educators to become computer literate: (1) admit you don't know about computers; (2) be patient with yourself; (3) read about technology; (4) get a home computer; (5) attend training; (6) experiment; (7) ask for assistance; and (8) talk with others about what works for them. (AEF)

Computing Whether She Belongs: Stereotypes Undermine Girls' Interest and Sense of Belonging in Computer Science

ERIC Educational Resources Information Center

Master, Allison; Cheryan, Sapna; Meltzoff, Andrew N.

2016-01-01

Computer science has one of the largest gender disparities in science, technology, engineering, and mathematics. An important reason for this disparity is that girls are less likely than boys to enroll in necessary "pipeline courses," such as introductory computer science. Two experiments investigated whether high-school girls' lower…

Adult Literacy Learning and Computer Technology: Features of Effective Computer-Assisted Learning Systems.

ERIC Educational Resources Information Center

Fahy, Patrick J.

Computer-assisted learning (CAL) can be used for adults functioning at any academic or grade level. In adult basic education (ABE), CAL can promote greater learning effectiveness and faster progress, concurrent learning and experience with computer literacy skills, privacy, and motivation. Adults who face barriers (financial, geographic, personal,…

The Evolution of Computer Based Learning Software Design: Computer Assisted Teaching Unit Experience.

ERIC Educational Resources Information Center

Blandford, A. E.; Smith, P. R.

1986-01-01

Describes the style of design of computer simulations developed by Computer Assisted Teaching Unit at Queen Mary College with reference to user interface, input and initialization, input data vetting, effective display screen use, graphical results presentation, and need for hard copy. Procedures and problems relating to academic involvement are…

Linguistic Analysis of Natural Language Communication with Computers.

ERIC Educational Resources Information Center

Thompson, Bozena Henisz

Interaction with computers in natural language requires a language that is flexible and suited to the task. This study of natural dialogue was undertaken to reveal those characteristics which can make computer English more natural. Experiments were made in three modes of communication: face-to-face, terminal-to-terminal, and human-to-computer,…

Some Hail 'Computational Science' as Biggest Advance Since Newton, Galileo.

ERIC Educational Resources Information Center

Turner, Judith Axler

1987-01-01

Computational science is defined as science done on a computer. A computer can serve as a laboratory for researchers who cannot experiment with their subjects, and as a calculator for those who otherwise might need centuries to solve some problems mathematically. The National Science Foundation's support of supercomputers is discussed. (MLW)