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

International Nuclear Information System (INIS)

Reister, D.B.

1997-04-01

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

Electromagnetic radiation damping of charges in external gravitational fields (weak field, slow motion approximation). [Harmonic coordinates, weak field slow-motion approximation, Green function

Energy Technology Data Exchange (ETDEWEB)

Rudolph, E [Max-Planck-Institut fuer Physik und Astrophysik, Muenchen (F.R. Germany)

1975-01-01

As a model for gravitational radiation damping of a planet the electromagnetic radiation damping of an extended charged body moving in an external gravitational field is calculated in harmonic coordinates using a weak field, slowing-motion approximation. Special attention is paid to the case where this gravitational field is a weak Schwarzschild field. Using Green's function methods for this purpose it is shown that in a slow-motion approximation there is a strange connection between the tail part and the sharp part: radiation reaction terms of the tail part can cancel corresponding terms of the sharp part. Due to this cancelling mechanism the lowest order electromagnetic radiation damping force in an external gravitational field in harmonic coordinates remains the flat space Abraham Lorentz force. It is demonstrated in this simplified model that a naive slow-motion approximation may easily lead to divergent higher order terms. It is shown that this difficulty does not arise up to the considered order.

Retarded coordinates based at a world line and the motion of a small black hole in an external universe

International Nuclear Information System (INIS)

Poisson, Eric

2004-01-01

In the first part of this article I present a system of retarded coordinates based at an arbitrary world line of an arbitrary curved spacetime. The retarded-time coordinate labels forward light cones that are centered on the world line, the radial coordinate is an affine parameter on the null generators of these light cones, and the angular coordinates are constant on each of these generators. The spacetime metric in the retarded coordinates is displayed as an expansion in powers of the radial coordinate and expressed in terms of the world line's acceleration vector and the spacetime's Riemann tensor evaluated at the world line. The formalism is illustrated in two examples, the first involving a comoving world line of a spatially flat cosmology, the other featuring an observer in circular motion in the Schwarzschild spacetime. The main application of the formalism is presented in the second part of the article, in which I consider the motion of a small black hole in an empty external universe. I use the retarded coordinates to construct the metric of the small black hole perturbed by the tidal field of the external universe, and the metric of the external universe perturbed by the presence of the black hole. Matching these metrics produces the MiSaTaQuWa equations of motion for the small black hole

Equations of motion in general relativity of a small charged black hole

International Nuclear Information System (INIS)

Futamase, T.; Hogan, P. A.; Itoh, Y.

2008-01-01

We present the details of a model in general relativity of a small charged black hole moving in an external gravitational and electromagnetic field. The importance of our model lies in the fact that we can derive the equations of motion of the black hole from the Einstein-Maxwell vacuum field equations without encountering infinities. The key assumptions which we base our results upon are that (a) the black hole is isolated and (b) near the black hole the wave fronts of the radiation generated by its motion are smoothly deformed spheres. The equations of motion which emerge fit the pattern of the original DeWitt and Brehme equations of motion (after they 'renormalize'). Our calculations are carried out in a coordinate system in which the null hypersurface histories of the wave fronts can be specified in a simple way, with the result that we obtain a new explicit form, particular to our model, for the well-known ''tail term'' in the equations of motion.

Topology of the Relative Motion: Circular and Eccentric Reference Orbit Cases

Science.gov (United States)

FontdecabaiBaig, Jordi; Metris, Gilles; Exertier, Pierre

2007-01-01

This paper deals with the topology of the relative trajectories in flight formations. The purpose is to study the different types of relative trajectories, their degrees of freedom, and to give an adapted parameterization. The paper also deals with the research of local circular motions. Even if they exist only when the reference orbit is circular, we extrapolate initial conditions to the eccentric reference orbit case.This alternative approach is complementary with traditional approaches in terms of cartesian coordinates or differences of orbital elements.

Relation between coordinate systems describing the dynamics of a loaded Stewart platform

Science.gov (United States)

Petrova, V. I.

2018-05-01

The paper puts forward formulae for transformation of coordinates in three coordinate frames used for the study of motion of a loaded Stewart platform, which is the central mechanism of the dynamic bench. A new method for finding the law of variation of coordinates is proposed. This method depends on solving the problem-specific system of differential equations.

Special relativity of non-inertial motions: A complementary theory to Einstein's SR

International Nuclear Information System (INIS)

Mocanu, C.I.

1999-01-01

In order to describe physical reality a special (gravity-free) relativity is needed that is founded upon general non-uniform motions as they occur in our environment and hold for the non-inertial reference frame of our laboratory. Such a generalized form of special relativity can be build upon an extension, at relativistic velocities, of Maxwell-Hertz electrodynamics (MHE), which is valid for non-uniform motions, but at small velocities only. The new electromagnetic theory called (in honor to Hertz) Hertz's Relativistic Electrodynamics (HRE), is completely independent and built-up in a completely different way as regards Einstein's Special Relativity (ESR). HRE, a coordinate-free formulation does not need postulates, but confirms the constancy principle of speed of light in vacuum. All experiments of first and second order in v/c are correctly interpreted. To this theory a Hertzian kinematics and dynamics are associated. HRE with its corresponding mechanics forms Hertz's Special Relativity (HSR), as a complementary theory to ESR. According to the principle of complementarity and neglecting the gravitational effects, the Extended Special Relativity (ExSR) is a double faced theory which becomes either ESR, when the motion is inertial or HSR when the motion is non-inertial. The complementarity of both theories assumes that the two descriptions cannot be employed for the same motion, being mutually exclusive. Consequently, to every statement of one of the ExSR corresponds a complementary statement of the other ExSR. The completeness of ESR with HSR ensures an extended view over the relativity in our physical world. (author)

Research on Coordinated Robotic Motion Control Based on Fuzzy Decoupling Method in Fluidic Environments

Directory of Open Access Journals (Sweden)

Wei Zhang

2014-01-01

Full Text Available The underwater recovery of autonomous underwater vehicles (AUV is a process of 6-DOF motion control, which is related to characteristics with strong nonlinearity and coupling. In the recovery mission, the vehicle requires high level control accuracy. Considering an AUV called BSAV, this paper established a kinetic model to describe the motion of AUV in the horizontal plane, which consisted of nonlinear equations. On the basis of this model, the main coupling variables were analyzed during recovery. Aiming at the strong coupling problem between the heading control and sway motion, we designed a decoupling compensator based on the fuzzy theory and the decoupling theory. We analyzed to the rules of fuzzy compensation, the input and output membership functions of fuzzy compensator, through compose operation and clear operation of fuzzy reasoning, and obtained decoupling compensation quantity. Simulation results show that the fuzzy decoupling controller effectively reduces the overshoot of the system, and improves the control precision. Through the water tank experiments and analysis of experimental data, the effectiveness and feasibility of AUV recovery movement coordinated control based on fuzzy decoupling method are validated successful, and show that the fuzzy decoupling control method has a high practical value in the recovery mission.

Relational Coordination in Danish General Practice

DEFF Research Database (Denmark)

Lundstrøm, Sanne Lykke

. The dissertation present the research study and a collection of three research papers prepared during the period from May 2010 to June 2014. Relational coordination and organisational social capital are measures of novel aspects of an organisation's performance. Relational coordination analyse the communication...... and relationship networks through which work is coordinated across functional and organisational boundaries. Previous studies have shown that relational coordination is positively associated with delivery of care for patients with chronic illness. Organisational social capital is used when analysing...... the psychosocial work environment in organisations, and is seen as a powerful resources for improving organisational performance. Relational coordination and organisational social capital may oer new insight and opportunities for general practice to learn. General practice provides cost-efficient, first...

A Sensory-Driven Trade-Off between Coordinated Motion in Social Prey and a Predator's Visual Confusion.

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Bertrand H Lemasson

2016-02-01

Full Text Available Social animals are capable of enhancing their awareness by paying attention to their neighbors, and prey found in groups can also confuse their predators. Both sides of these sensory benefits have long been appreciated, yet less is known of how the perception of events from the perspectives of both prey and predator can interact to influence their encounters. Here we examined how a visual sensory mechanism impacts the collective motion of prey and, subsequently, how their resulting movements influenced predator confusion and capture ability. We presented virtual prey to human players in a targeting game and measured the speed and accuracy with which participants caught designated prey. As prey paid more attention to neighbor movements their collective coordination increased, yet increases in prey coordination were positively associated with increases in the speed and accuracy of attacks. However, while attack speed was unaffected by the initial state of the prey, accuracy dropped significantly if the prey were already organized at the start of the attack, rather than in the process of self-organizing. By repeating attack scenarios and masking the targeted prey's neighbors we were able to visually isolate them and conclusively demonstrate how visual confusion impacted capture ability. Delays in capture caused by decreased coordination amongst the prey depended upon the collection motion of neighboring prey, while it was primarily the motion of the targets themselves that determined capture accuracy. Interestingly, while a complete loss of coordination in the prey (e.g., a flash expansion caused the greatest delay in capture, such behavior had little effect on capture accuracy. Lastly, while increases in collective coordination in prey enhanced personal risk, traveling in coordinated groups was still better than appearing alone. These findings demonstrate a trade-off between the sensory mechanisms that can enhance the collective properties that

Collective coordinate models of domain wall motion in perpendicularly magnetized systems under the spin hall effect and longitudinal fields

Energy Technology Data Exchange (ETDEWEB)

Nasseri, S. Ali, E-mail: ali.nasseri@isi.it [ISI Foundation - Via Alassio 11/c –10126 Torino (Italy); Politecnico di Torino - Corso Duca degli Abruzzi 24, 10129 Torino (Italy); Moretti, Simone; Martinez, Eduardo [University of Salamanca - Cardenal Plá y Deniel, 22, 37008 Salamanca (Spain); Serpico, Claudio [ISI Foundation - Via Alassio 11/c –10126 Torino (Italy); University of Naples Federico II - Via Claudio 21, 80125 Napoli (Italy); Durin, Gianfranco [ISI Foundation - Via Alassio 11/c –10126 Torino (Italy); Istituto Nazionale di Ricerca Metrologica (INRIM) - Strada delle Cacce 91, 10135 Torino (Italy)

2017-03-15

Recent studies on heterostructures of ultrathin ferromagnets sandwiched between a heavy metal layer and an oxide have highlighted the importance of spin-orbit coupling (SOC) and broken inversion symmetry in domain wall (DW) motion. Specifically, chiral DWs are stabilized in these systems due to the Dzyaloshinskii-Moriya interaction (DMI). SOC can also lead to enhanced current induced DW motion, with the Spin Hall effect (SHE) suggested as the dominant mechanism for this observation. The efficiency of SHE driven DW motion depends on the internal magnetic structure of the DW, which could be controlled using externally applied longitudinal in-plane fields. In this work, micromagnetic simulations and collective coordinate models are used to study current-driven DW motion under longitudinal in-plane fields in perpendicularly magnetized samples with strong DMI. Several extended collective coordinate models are developed to reproduce the micromagnetic results. While these extended models show improvements over traditional models of this kind, there are still discrepancies between them and micromagnetic simulations which require further work. - Highlights: • Moving DWs in PMA material maintain their structure under longitudinal in-plane fields. • As a result of longitudinal fields, magnetization in the domains becomes canted. • A critical longitudinal field was identified and correlated with the DMI strength. • A canted collective coordinate model was developed for DW motion under in-plane fields.

Rapid and coordinated processing of global motion images by local clusters of retinal ganglion cells.

Science.gov (United States)

Matsumoto, Akihiro; Tachibana, Masao

2017-01-01

Even when the body is stationary, the whole retinal image is always in motion by fixational eye movements and saccades that move the eye between fixation points. Accumulating evidence indicates that the brain is equipped with specific mechanisms for compensating for the global motion induced by these eye movements. However, it is not yet fully understood how the retina processes global motion images during eye movements. Here we show that global motion images evoke novel coordinated firing in retinal ganglion cells (GCs). We simultaneously recorded the firing of GCs in the goldfish isolated retina using a multi-electrode array, and classified each GC based on the temporal profile of its receptive field (RF). A moving target that accompanied the global motion (simulating a saccade following a period of fixational eye movements) modulated the RF properties and evoked synchronized and correlated firing among local clusters of the specific GCs. Our findings provide a novel concept for retinal information processing during eye movements.

Coordination of spinal motion in the transverse and frontal planes during walking in people with and without recurrent low back pain.

Science.gov (United States)

Crosbie, Jack; de Faria Negrão Filho, Ruben; Nascimento, Dafne Port; Ferreira, Paulo

2013-03-01

Observational cohort study. To investigate spinal coordination during preferred and fast speed walking in pain-free subjects with and without a history of recurrent low back pain (LBP). Dynamic motion of the spine during walking is compromised in the presence of back pain (LBP), but its analysis often presents some challenges. The coexistence of significant symptoms may change gait because of pain or adaptation of the musculoskeletal structures or both. A history of LBP without the overlay of a current symptomatic episode allows a better model in which to explore the impact on spinal coordination during walking. Spinal and lower limb segmental motions were tracked using electromagnetic sensors. Analyses were conducted to explore the synchrony and spatial coordination of the segments and to compare the control and subjects with LBP. We found no apparent differences between the groups for either overall amplitude of motion or most indicators of coordination in the lumbar region; however, there were significant postural differences in the mid-stance phase and other indicators of less phase locking in controls compared with subjects with LBP. The lower thoracic spinal segment was more affected by the history of back pain than the lumbar segment. Although small, there were indicators that alterations in spinal movement and coordination in subjects with recurrent LBP were due to adaptive changes rather than the presence of pain.

The roles of non-retinotopic motions in visual search

Directory of Open Access Journals (Sweden)

Ryohei eNakayama

2016-06-01

Full Text Available In visual search, a moving target among stationary distracters is detected more rapidly and more efficiently than a static target among moving distracters. Here we examined how this search asymmetry depends on motion signals from three distinct coordinate system – retinal, relative, and spatiotopic (head/body-centered. Our search display consisted of a target element, distracters elements, and a fixation point tracked by observers. Each element was composed of a spatial carrier grating windowed by a Gaussian envelope, and the motions of carriers, windows, and fixation were manipulated independently and used in various combinations to decouple the respective effects of motion coordinates systems on visual search asymmetry. We found that retinal motion hardly contributes to reaction times and search slopes but that relative and spatiotopic motions contribute to them substantially. Results highlight the important roles of non-retinotopic motions for guiding observer attention in visual search.

Evaluating the Relational Coordination instrument

DEFF Research Database (Denmark)

Edwards, Kasper; Lundstrøm, Sanne Lykke

2014-01-01

consistency, interrater agreement and reliability, structural validity, content validity. However as relational coordination is being used as a diagnostics tool it is important to examine further if the instrument can measure changes. Indeed we need to know how precise and sensitive the instrument is when....... We distinguish between statistical and clinical significance. Statistical significance is calculated using T-test. Clinical significance is the minimal amount of change in relational coordination score that is not considered noise. Sensitivity of the instrument i.e. the ability of the instrument...

Optimum collective submanifold in resonant cases by the self-consistent collective-coordinate method for large-amplitude collective motion

International Nuclear Information System (INIS)

Hashimoto, Y.; Marumori, T.; Sakata, F.

1987-01-01

With the purpose of clarifying characteristic difference of the optimum collective submanifolds in nonresonant and resonant cases, we develop an improved method of solving the basic equations of the self-consistent collective-coordinate (SCC) method for large-amplitude collective motion. It is shown that, in the resonant cases, there inevitably arise essential coupling terms which break the maximal-decoupling property of the collective motion, and we have to extend the optimum collective submanifold so as to properly treat the degrees of freedom which bring about the resonances

Numerical relativity in spherical coordinates with the Einstein Toolkit

Science.gov (United States)

Mewes, Vassilios; Zlochower, Yosef; Campanelli, Manuela; Ruchlin, Ian; Etienne, Zachariah B.; Baumgarte, Thomas W.

2018-04-01

Numerical relativity codes that do not make assumptions on spatial symmetries most commonly adopt Cartesian coordinates. While these coordinates have many attractive features, spherical coordinates are much better suited to take advantage of approximate symmetries in a number of astrophysical objects, including single stars, black holes, and accretion disks. While the appearance of coordinate singularities often spoils numerical relativity simulations in spherical coordinates, especially in the absence of any symmetry assumptions, it has recently been demonstrated that these problems can be avoided if the coordinate singularities are handled analytically. This is possible with the help of a reference-metric version of the Baumgarte-Shapiro-Shibata-Nakamura formulation together with a proper rescaling of tensorial quantities. In this paper we report on an implementation of this formalism in the Einstein Toolkit. We adapt the Einstein Toolkit infrastructure, originally designed for Cartesian coordinates, to handle spherical coordinates, by providing appropriate boundary conditions at both inner and outer boundaries. We perform numerical simulations for a disturbed Kerr black hole, extract the gravitational wave signal, and demonstrate that the noise in these signals is orders of magnitude smaller when computed on spherical grids rather than Cartesian grids. With the public release of our new Einstein Toolkit thorns, our methods for numerical relativity in spherical coordinates will become available to the entire numerical relativity community.

Protein flexibility: coordinate uncertainties and interpretation of structural differences

Energy Technology Data Exchange (ETDEWEB)

Rashin, Alexander A., E-mail: alexander-rashin@hotmail.com [BioChemComp Inc., 543 Sagamore Avenue, Teaneck, NJ 07666 (United States); LH Baker Center for Bioinformatics and Department of Biochemistry, Biophysics and Molecular Biology, 112 Office and Lab Building, Iowa State University, Ames, IA 50011-3020 (United States); Rashin, Abraham H. L. [BioChemComp Inc., 543 Sagamore Avenue, Teaneck, NJ 07666 (United States); Rutgers, The State University of New Jersey, 22371 BPO WAY, Piscataway, NJ 08854-8123 (United States); Jernigan, Robert L. [LH Baker Center for Bioinformatics and Department of Biochemistry, Biophysics and Molecular Biology, 112 Office and Lab Building, Iowa State University, Ames, IA 50011-3020 (United States); BioChemComp Inc., 543 Sagamore Avenue, Teaneck, NJ 07666 (United States)

2009-11-01

Criteria for the interpretability of coordinate differences and a new method for identifying rigid-body motions and nonrigid deformations in protein conformational changes are developed and applied to functionally induced and crystallization-induced conformational changes. Valid interpretations of conformational movements in protein structures determined by X-ray crystallography require that the movement magnitudes exceed their uncertainty threshold. Here, it is shown that such thresholds can be obtained from the distance difference matrices (DDMs) of 1014 pairs of independently determined structures of bovine ribonuclease A and sperm whale myoglobin, with no explanations provided for reportedly minor coordinate differences. The smallest magnitudes of reportedly functional motions are just above these thresholds. Uncertainty thresholds can provide objective criteria that distinguish between true conformational changes and apparent ‘noise’, showing that some previous interpretations of protein coordinate changes attributed to external conditions or mutations may be doubtful or erroneous. The use of uncertainty thresholds, DDMs, the newly introduced CDDMs (contact distance difference matrices) and a novel simple rotation algorithm allows a more meaningful classification and description of protein motions, distinguishing between various rigid-fragment motions and nonrigid conformational deformations. It is also shown that half of 75 pairs of identical molecules, each from the same asymmetric crystallographic cell, exhibit coordinate differences that range from just outside the coordinate uncertainty threshold to the full magnitude of large functional movements. Thus, crystallization might often induce protein conformational changes that are comparable to those related to or induced by the protein function.

Inter-joint coordination between hips and trunk during downswings: Effects on the clubhead speed.

Science.gov (United States)

Choi, Ahnryul; Lee, In-Kwang; Choi, Mun-Taek; Mun, Joung Hwan

2016-10-01

Understanding of the inter-joint coordination between rotational movement of each hip and trunk in golf would provide basic knowledge regarding how the neuromuscular system organises the related joints to perform a successful swing motion. In this study, we evaluated the inter-joint coordination characteristics between rotational movement of the hips and trunk during golf downswings. Twenty-one right-handed male professional golfers were recruited for this study. Infrared cameras were installed to capture the swing motion. The axial rotation angle, angular velocity and inter-joint coordination were calculated by the Euler angle, numerical difference method and continuous relative phase, respectively. A more typical inter-joint coordination demonstrated in the leading hip/trunk than trailing hip/trunk. Three coordination characteristics of the leading hip/trunk reported a significant relationship with clubhead speed at impact (r joint coordination strategies have the great potential to use a biomechanical guideline to improve the golf swing performance of unskilled golfers.

Relations between Automatically Extracted Motion Features and the Quality of Mother-Infant Interactions at 4 and 13 Months.

Science.gov (United States)

Egmose, Ida; Varni, Giovanna; Cordes, Katharina; Smith-Nielsen, Johanne; Væver, Mette S; Køppe, Simo; Cohen, David; Chetouani, Mohamed

2017-01-01

Bodily movements are an essential component of social interactions. However, the role of movement in early mother-infant interaction has received little attention in the research literature. The aim of the present study was to investigate the relationship between automatically extracted motion features and interaction quality in mother-infant interactions at 4 and 13 months. The sample consisted of 19 mother-infant dyads at 4 months and 33 mother-infant dyads at 13 months. The coding system Coding Interactive Behavior (CIB) was used for rating the quality of the interactions. Kinetic energy of upper-body, arms and head motion was calculated and used as segmentation in order to extract coarse- and fine-grained motion features. Spearman correlations were conducted between the composites derived from the CIB and the coarse- and fine-grained motion features. At both 4 and 13 months, longer durations of maternal arm motion and infant upper-body motion were associated with more aversive interactions, i.e., more parent-led interactions and more infant negativity. Further, at 4 months, the amount of motion silence was related to more adaptive interactions, i.e., more sensitive and child-led interactions. Analyses of the fine-grained motion features showed that if the mother coordinates her head movements with her infant's head movements, the interaction is rated as more adaptive in terms of less infant negativity and less dyadic negative states. We found more and stronger correlations between the motion features and the interaction qualities at 4 compared to 13 months. These results highlight that motion features are related to the quality of mother-infant interactions. Factors such as infant age and interaction set-up are likely to modify the meaning and importance of different motion features.

Coordinated Speed Oscillations in Schooling Killifish Enrich Social Communication

Science.gov (United States)

Swain, Daniel T.; Couzin, Iain D.; Leonard, Naomi Ehrich

2015-10-01

We examine the spatial dynamics of individuals in small schools of banded killifish ( Fundulus diaphanus) that exhibit rhythmic, oscillating speed, typically with sustained, coordinated, out-of-phase speed oscillations as they move around a shallow water tank. We show that the relative motion among the fish yields a periodically time-varying network of social interactions that enriches visually driven social communication. The oscillations lead to the regular making and breaking of occlusions, which we term "switching." We show that the rate of convergence to consensus (biologically, the capacity for individuals in groups to achieve effective coordinated motion) governed by the switching outperforms static alternatives, and performs as well as the less practical case of every fish sensing every other fish. We show further that the oscillations in speed yield oscillations in relative bearing between fish over a range that includes the angles previously predicted to be optimal for a fish to detect changes in heading and speed of its neighbors. To investigate systematically, we derive and analyze a dynamic model of interacting agents that move with oscillatory speed. We show that coordinated circular motion of the school leads to systematic cycling of spatial ordering of agents and possibilities for enriched spatial density of measurements of the external environment. Our results highlight the potential benefits of dynamic communication topologies in collective animal behavior, and suggest new, useful control laws for the distributed coordination of mobile robotic networks.

Magnetic Coordinate Systems

Science.gov (United States)

Laundal, K. M.; Richmond, A. D.

2017-03-01

Geospace phenomena such as the aurora, plasma motion, ionospheric currents and associated magnetic field disturbances are highly organized by Earth's main magnetic field. This is due to the fact that the charged particles that comprise space plasma can move almost freely along magnetic field lines, but not across them. For this reason it is sensible to present such phenomena relative to Earth's magnetic field. A large variety of magnetic coordinate systems exist, designed for different purposes and regions, ranging from the magnetopause to the ionosphere. In this paper we review the most common magnetic coordinate systems and describe how they are defined, where they are used, and how to convert between them. The definitions are presented based on the spherical harmonic expansion coefficients of the International Geomagnetic Reference Field (IGRF) and, in some of the coordinate systems, the position of the Sun which we show how to calculate from the time and date. The most detailed coordinate systems take the full IGRF into account and define magnetic latitude and longitude such that they are constant along field lines. These coordinate systems, which are useful at ionospheric altitudes, are non-orthogonal. We show how to handle vectors and vector calculus in such coordinates, and discuss how systematic errors may appear if this is not done correctly.

Geometry of the self-consistent collective-coordinate method for the large-amplitude collective motion

International Nuclear Information System (INIS)

Sakata, Fumihiko; Marumori, Toshio; Hashimoto, Yukio; Une, Tsutomu.

1983-05-01

The geometry of the self-consistent collective-coordinate (SCC) method formulated within the framework of the time-dependent Hartree-Fock (TDHF) theory is investigated by associating the variational parameters with a symplectic manifold (a TDHF manifold). With the use of a canonical-variables parametrization, it is shown that the TDHF equation is equivalent to the canonical equations of motion in classical mechanics in the TDHF manifold. This enables us to investigate geometrical structure of the SCC method in the language of the classical mechanics. The SCC method turns out to give a prescription how to dynamically extract a ''maximally-decoupled'' collective submanifold (hypersurface) out of the TDHF manifold, in such a way that a certain kind of trajectories corresponding to the large-amplitude collective motion under consideration can be reproduced on the hypersurface as precisely as possible. The stability of the hypersurface at each point on it is investigated, in order to see whether the hypersurface obtained by the SCC method is really an approximate integral surface in the TDHF manifold or not. (author)

Analysis of Large Flexible Body Deformation in Multibody Systems Using Absolute Coordinates

Energy Technology Data Exchange (ETDEWEB)

Dombrowski, Stefan von [Institute of Robotics and Mechatronics, German Aerospace Center (DLR) (Germany)], E-mail: stefan.von.dombrowski@dlr.de

2002-11-15

To consider large deformation problems in multibody system simulations a finite element approach, called absolute nodal coordinate.formulation,has been proposed. In this formulation absolute nodal coordinates and their material derivatives are applied to represent both deformation and rigid body motion. The choice of nodal variables allows a fully nonlinear representation of rigid body motion and can provide the exact rigid body inertia in the case of large rotations. The methodology is especially suited for but not limited to modeling of beams, cables and shells in multibody dynamics.This paper summarizes the absolute nodal coordinate formulation for a 3D Euler-Bernoulli beam model, in particular the definition of nodal variables, corresponding generalized elastic and inertia forces and equations of motion. The element stiffness matrix is a nonlinear function of the nodal variables even in the case of linearized strain/displacement relations. Nonlinear strain/displacement relations can be calculated from the global displacements using quadrature formulae.Computational examples are given which demonstrate the capabilities of the applied methodology. Consequences of the choice of shape.functions on the representation of internal forces are discussed. Linearized strain/displacement modeling is compared to the nonlinear approach and significant advantages of the latter, when using the absolute nodal coordinate formulation, are outlined.

Analysis of Large Flexible Body Deformation in Multibody Systems Using Absolute Coordinates

International Nuclear Information System (INIS)

Dombrowski, Stefan von

2002-01-01

To consider large deformation problems in multibody system simulations a finite element approach, called absolute nodal coordinate.formulation,has been proposed. In this formulation absolute nodal coordinates and their material derivatives are applied to represent both deformation and rigid body motion. The choice of nodal variables allows a fully nonlinear representation of rigid body motion and can provide the exact rigid body inertia in the case of large rotations. The methodology is especially suited for but not limited to modeling of beams, cables and shells in multibody dynamics.This paper summarizes the absolute nodal coordinate formulation for a 3D Euler-Bernoulli beam model, in particular the definition of nodal variables, corresponding generalized elastic and inertia forces and equations of motion. The element stiffness matrix is a nonlinear function of the nodal variables even in the case of linearized strain/displacement relations. Nonlinear strain/displacement relations can be calculated from the global displacements using quadrature formulae.Computational examples are given which demonstrate the capabilities of the applied methodology. Consequences of the choice of shape.functions on the representation of internal forces are discussed. Linearized strain/displacement modeling is compared to the nonlinear approach and significant advantages of the latter, when using the absolute nodal coordinate formulation, are outlined

Short-Term Comparison of Several Solutinos of Elliptic Relative Motion

Directory of Open Access Journals (Sweden)

Jung Hyun Jo

2007-12-01

Full Text Available Recently introduced, several explicit solutions of relative motion between neighboring elliptic satellite orbits are reviewed. The performance of these solutions is compared with an analytic solution of the general linearized equation of motion. The inversion solution by the Hill-Clohessy-Wiltshire equations is used to produce the initial condition of numerical results. Despite the difference of the reference orbit, the relative motion with the relatively small eccentricity shows the similar results on elliptic case and circular case. In case of the 'chief' satellite with the relatively large eccentricity, HCW equation with the circular reference orbit has relatively larger error than other elliptic equation of motion does.

Directional bias of illusory stream caused by relative motion adaptation.

Science.gov (United States)

Tomimatsu, Erika; Ito, Hiroyuki

2016-07-01

Enigma is an op-art painting that elicits an illusion of rotational streaming motion. In the present study, we tested whether adaptation to various motion configurations that included relative motion components could be reflected in the directional bias of the illusory stream. First, participants viewed the center of a rotating Enigma stimulus for adaptation. There was no physical motion on the ring area. During the adaptation period, the illusory stream on the ring was mainly seen in the direction opposite to that of the physical rotation. After the physical rotation stopped, the illusory stream on the ring was mainly seen in the same direction as that of the preceding physical rotation. Moreover, adapting to strong relative motion induced a strong bias in the illusory motion direction in the subsequently presented static Enigma stimulus. The results suggest that relative motion detectors corresponding to the ring area may produce the illusory stream of Enigma. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

Homothetic motions in general relativity

International Nuclear Information System (INIS)

McIntosh, C.B.G.

1976-01-01

Properties of homothetic or self-similar motions in general relativity are examined with particular reference to vacuum and perfect-fluid space-times. The role of the homothetic bivector with components Hsub((a;b)) formed from the homothetic vector H is discussed in some detail. It is proved that a vacuum space-time only admits a nontrivial homothetic motion if the homothetic vector field is non-null and is not hypersurface orthogonal. As a subcase of a more general result it is shown that a perfect-fluid space-time cannot admit a non-trivial homothetic vector which is orthogonal to the fluid velocity 4-vector. (author)

A Motion Planning Approach to Studying Molecular Motions

KAUST Repository

Amato, Nancy M.

2010-01-01

While structurally very different, protein and RNA molecules share an important attribute. The motions they undergo are strongly related to the function they perform. For example, many diseases such as Mad Cow disease or Alzheimer\\'s disease are associated with protein misfolding and aggregation. Similarly, RNA folding velocity may regulate the plasmid copy number, and RNA folding kinetics can regulate gene expression at the translational level. Knowledge of the stability, folding, kinetics and detailed mechanics of the folding process may help provide insight into how proteins and RNAs fold. In this paper, we present an overview of our work with a computational method we have adapted from robotic motion planning to study molecular motions. We have validated against experimental data and have demonstrated that our method can capture biological results such as stochastic folding pathways, population kinetics of various conformations, and relative folding rates. Thus, our method provides both a detailed view (e.g., individual pathways) and a global view (e.g., population kinetics, relative folding rates, and reaction coordinates) of energy landscapes of both proteins and RNAs. We have validated these techniques by showing that we observe the same relative folding rates as shown in experiments for structurally similar protein molecules that exhibit different folding behaviors. Our analysis has also been able to predict the same relative gene expression rate for wild-type MS2 phage RNA and three of its mutants.

A canonical perturbation method for computing the guiding-center motion in magnetized axisymmetric plasma columns

International Nuclear Information System (INIS)

Gratreau, P.

1987-01-01

The motion of charged particles in a magnetized plasma column, such as that of a magnetic mirror trap or a tokamak, is determined in the framework of the canonical perturbation theory through a method of variation of constants which preserves the energy conservation and the symmetry invariance. The choice of a frame of coordinates close to that of the magnetic coordinates allows a relatively precise determination of the guiding-center motion with a low-ordered approximation in the adiabatic parameter. A Hamiltonian formulation of the motion equations is obtained

Social network size relates to developmental neural sensitivity to biological motion

Directory of Open Access Journals (Sweden)

L.A. Kirby

2018-04-01

Full Text Available The ability to perceive others’ actions and goals from human motion (i.e., biological motion perception is a critical component of social perception and may be linked to the development of real-world social relationships. Adult research demonstrates two key nodes of the brain’s biological motion perception system—amygdala and posterior superior temporal sulcus (pSTS—are linked to variability in social network properties. The relation between social perception and social network properties, however, has not yet been investigated in middle childhood—a time when individual differences in social experiences and social perception are growing. The aims of this study were to (1 replicate past work showing amygdala and pSTS sensitivity to biological motion in middle childhood; (2 examine age-related changes in the neural sensitivity for biological motion, and (3 determine whether neural sensitivity for biological motion relates to social network characteristics in children. Consistent with past work, we demonstrate a significant relation between social network size and neural sensitivity for biological motion in left pSTS, but do not find age-related change in biological motion perception. This finding offers evidence for the interplay between real-world social experiences and functional brain development and has important implications for understanding disorders of atypical social experience. Keywords: Biological motion, Social networks, Middle childhood, Neural specialization, Brain-behavior relations, pSTS

On the relative motions of long-lived Pacific mantle plumes.

Science.gov (United States)

Konrad, Kevin; Koppers, Anthony A P; Steinberger, Bernhard; Finlayson, Valerie A; Konter, Jasper G; Jackson, Matthew G

2018-02-27

Mantle plumes upwelling beneath moving tectonic plates generate age-progressive chains of volcanos (hotspot chains) used to reconstruct plate motion. However, these hotspots appear to move relative to each other, implying that plumes are not laterally fixed. The lack of age constraints on long-lived, coeval hotspot chains hinders attempts to reconstruct plate motion and quantify relative plume motions. Here we provide 40 Ar/ 39 Ar ages for a newly identified long-lived mantle plume, which formed the Rurutu hotspot chain. By comparing the inter-hotspot distances between three Pacific hotspots, we show that Hawaii is unique in its strong, rapid southward motion from 60 to 50 Myrs ago, consistent with paleomagnetic observations. Conversely, the Rurutu and Louisville chains show little motion. Current geodynamic plume motion models can reproduce the first-order motions for these plumes, but only when each plume is rooted in the lowermost mantle.

The Hubble law and the spiral structures of galaxies from equations of motion in general relativity

International Nuclear Information System (INIS)

Sachs, M.

1975-01-01

Fully exploiting the Lie group that characterizes the underlying symmetry of general relativity theory, Einstein's tensor formalism factorizes, yielding a generalized (16-component) quaternion field formalism. The associated generalized geodesic equation, taken as the equation of motion of a star, predicts the Hubble law from one approximation for the generally covariant equations of motion, and the spiral structure of galaxies from another approximation. These results depend on the imposition of appropriate boundary conditions. The Hubble law follows when the boundary conditions derive from the oscillating model cosmology, and not from the other cosmological models. The spiral structures of the galaxies follow from the same boundary conditions, but with a different time scale than for the whole universe. The solutions that imply the spiral motion are Fresnel integrals. These predict the star's motion to be along the 'Cornu Spiral'. The part of this spiral in the first quadrant is the imploding phase of the galaxy, corresponding to a motion with continually decreasing radii, approaching the galactic center as time increases. The part of the Cornu Spiral' in the third quadrant is the exploding phase, corresponding to continually increasing radii, as the star moves out from the hub. The spatial origin in the coordinate system of this curve is the inflection point, where the explosion changes to implosion. The two- (or many-) armed spiral galaxies are explained here in terms of two (or many) distinct explosions occurring at displaced times, in the domain of the rotating, planar galaxy. (author)

Final state predictions for J2 gravity perturbed motion of the Earth’s artificial satellites using Bispherical coordinates

Directory of Open Access Journals (Sweden)

M.A. Sharaf

2013-06-01

Full Text Available In this paper, initial value problem for dynamical astronomy will be established using Bispherical coordinates. A computational algorithm is developed for the final state predictions for J2 gravity perturbed motion of the Earth’s artificial satellites. This algorithm is important in targeting, rendezvous maneuvers as well for scientific researches. The applications of the algorithm are illustrated by numerical examples of some test orbits of different eccentricities. The numerical results are extremely accurate and efficient.

Relative Status Determination for Spacecraft Relative Motion Based on Dual Quaternion

Directory of Open Access Journals (Sweden)

Jun Sun

2014-01-01

Full Text Available For the two-satellite formation, the relative motion and attitude determination algorithm is a key component that affects the flight quality and mission efficiency. The relative status determination algorithm is proposed based on the Extended Kalman Filter (EKF and the system state optimal estimate linearization. Aiming at the relative motion of the spacecraft formation navigation problem, the spacecraft relative kinematics and dynamics model are derived from the dual quaternion in the algorithm. Then taking advantage of EKF technique, combining with the dual quaternion integrated dynamic models, considering the navigation algorithm using the fusion measurement by the gyroscope and star sensors, the relative status determination algorithm is designed. At last the simulation is done to verify the feasibility of the algorithm. The simulation results show that the EKF algorithm has faster convergence speed and higher accuracy.

Motion video analysis using planar parallax

Science.gov (United States)

Sawhney, Harpreet S.

1994-04-01

Motion and structure analysis in video sequences can lead to efficient descriptions of objects and their motions. Interesting events in videos can be detected using such an analysis--for instance independent object motion when the camera itself is moving, figure-ground segregation based on the saliency of a structure compared to its surroundings. In this paper we present a method for 3D motion and structure analysis that uses a planar surface in the environment as a reference coordinate system to describe a video sequence. The motion in the video sequence is described as the motion of the reference plane, and the parallax motion of all the non-planar components of the scene. It is shown how this method simplifies the otherwise hard general 3D motion analysis problem. In addition, a natural coordinate system in the environment is used to describe the scene which can simplify motion based segmentation. This work is a part of an ongoing effort in our group towards video annotation and analysis for indexing and retrieval. Results from a demonstration system being developed are presented.

The motion of a charged particle in general relativity

International Nuclear Information System (INIS)

Ludvigsen, M.

1979-01-01

A new approach to the problem of the motion of a self-interacting massive charged particle in general relativity is presented. A charged Robinson-Trautman solution is used as a general relativistic model of such a particle. Such a solution is shown to generate a unique world line in its own H space, which is interpreted as the world line of the particle. Using the R-T dynamical relations, the equation of motion of the particle is derived, which, in the limiting case of zero curvature, is shown to be the same as the classical Lorentz-Dirac equation of motion. (author)

Self-consistent collective coordinate method for large amplitude collective motions

International Nuclear Information System (INIS)

Sakata, F.; Hashimoto, Y.; Marumori, T.; Une, T.

1982-01-01

A recent development of the self-consistent collective coordinate method is described. The self-consistent collective coordinate method was proposed on the basis of the fundamental principle called the invariance principle of the Schroedinger equation. If this is formulated within a framework of the time dependent Hartree Fock (TDHF) theory, a classical version of the theory is obtained. A quantum version of the theory is deduced by formulating it within a framework of the unitary transformation method with auxiliary bosons. In this report, the discussion is concentrated on a relation between the classical theory and the quantum theory, and an applicability of the classical theory. The aim of the classical theory is to extract a maximally decoupled collective subspace out of a huge dimensional 1p - 1h parameter space introduced by the TDHF theory. An intimate similarity between the classical theory and a full quantum boson expansion method (BEM) was clarified. Discussion was concentrated to a simple Lipkin model. Then a relation between the BEM and the unitary transformation method with auxiliary bosons was discussed. It became clear that the quantum version of the theory had a strong relation to the BEM, and that the BEM was nothing but a quantum analogue of the present classical theory. The present theory was compared with the full TDHF calculation by using a simple model. (Kato, T.)

Deriving motion from megavoltage localization cone beam computed tomography scans

International Nuclear Information System (INIS)

Alfredo C Siochi, R

2009-01-01

Cone beam computed tomography (CBCT) projection data consist of views of a moving point (e.g. diaphragm apex). The point is selected in identification views of extreme motion (two inhale, two exhale). The room coordinates of the extreme points are determined by source-to-view ray tracing intersections. Projected to other views, these points become opposite corners of a motion-bounding box. The view coordinates of the point, relative to the box, are used to interpolate between extreme room coordinates. Along with the views' time stamps, this provides the point's room coordinates as a function of time. CBCT-derived trajectories of a tungsten pin, moving 3 cm cranio-caudally and 1 cm elsewhere, deviate from expected ones by at most 1.06 mm. When deviations from the ideal imaging geometry are considered, mean errors are less than 0.2 mm. While CBCT-derived cranio-caudal positions are insensitive to the choice of identification views, the bounding box determination requires view separations between 15 and 163 deg. Inhale views with the two largest amplitudes should be used, though corrections can account for different amplitudes. The information could be used to calibrate motion surrogates, adaptively define phase triggers immediately before gated radiotherapy and provide phase and amplitude sorting for 4D CBCT.

Collective motion and the generator coordinate method

International Nuclear Information System (INIS)

Passos, E.J.V. de

1981-01-01

The generator coordinate method is used to construct a collective subspace of the many-body Hylbert space. The construction is based on the analysis of the properties of the overlaps of the generator states. Some well-known misbehaviours of the generator coordinate weight functions are clearly identified as of kinematical origin. A standard orthonormal representation in the collective subspace is introduced which eliminates them. It is also indicated how appropriate collective dynamical variables can be defined a posteriori. To illustrate the properties of the collective subspaces applications are made to a) translational invariant overlap kernels b) to one and two-conjugate parameter families of generator states. (Author) [pt

Third post-Newtonian dynamics of compact binaries: equations of motion in the centre-of-mass frame

CERN Document Server

Blanchet, L

2003-01-01

The equations of motion of compact binary systems and their associated Lagrangian formulation have been derived in previous works at the third post-Newtonian (3PN) approximation of general relativity in harmonic coordinates. In the present work, we investigate the binary's relative dynamics in the centre-of-mass frame (centre of mass located at the origin of the coordinates). We obtain the 3PN-accurate expressions of the centre-of-mass positions and equations of the relative binary motion. We show that the equations derive from a Lagrangian (neglecting the radiation reaction), from which we deduce the conserved centre-of-mass energy and angular momentum at the 3PN order. The harmonic-coordinates centre-of-mass Lagrangian is equivalent, via a contact transformation of the particles' variables, to the centre-of-mass Hamiltonian in ADM coordinates that is known from the post-Newtonian ADM-Hamiltonian formalism. As an application we investigate the dynamical stability of circular binary orbits at the 3PN order.

Dynamics of relative motion of test particles in general relativity

International Nuclear Information System (INIS)

Bazanski, S.L.

1977-01-01

Several variational principles which lead to the first and the second geodesic deviation equations, recently formulated by the author and used for the description of the relative motion of test particles in general relativity are presented. Relations between these principles are investigated and exhibited. The Hamilton-Jacobi equation is also studied for these generalized deviations and the conservation laws appearing here are discussed

SENR /NRPy + : Numerical relativity in singular curvilinear coordinate systems

Science.gov (United States)

Ruchlin, Ian; Etienne, Zachariah B.; Baumgarte, Thomas W.

2018-03-01

We report on a new open-source, user-friendly numerical relativity code package called SENR /NRPy + . Our code extends previous implementations of the BSSN reference-metric formulation to a much broader class of curvilinear coordinate systems, making it ideally suited to modeling physical configurations with approximate or exact symmetries. In the context of modeling black hole dynamics, it is orders of magnitude more efficient than other widely used open-source numerical relativity codes. NRPy + provides a Python-based interface in which equations are written in natural tensorial form and output at arbitrary finite difference order as highly efficient C code, putting complex tensorial equations at the scientist's fingertips without the need for an expensive software license. SENR provides the algorithmic framework that combines the C codes generated by NRPy + into a functioning numerical relativity code. We validate against two other established, state-of-the-art codes, and achieve excellent agreement. For the first time—in the context of moving puncture black hole evolutions—we demonstrate nearly exponential convergence of constraint violation and gravitational waveform errors to zero as the order of spatial finite difference derivatives is increased, while fixing the numerical grids at moderate resolution in a singular coordinate system. Such behavior outside the horizons is remarkable, as numerical errors do not converge to zero near punctures, and all points along the polar axis are coordinate singularities. The formulation addresses such coordinate singularities via cell-centered grids and a simple change of basis that analytically regularizes tensor components with respect to the coordinates. Future plans include extending this formulation to allow dynamical coordinate grids and bispherical-like distribution of points to efficiently capture orbiting compact binary dynamics.

It's, Like, Relative Motion at the Mall

Science.gov (United States)

Robinett, R. W.

2003-03-01

Almost all introductory textbooks, both algebra- and calculus-based, include sections on relative motion and relative velocity, in both one and two dimensions. The most popular examples in discussions of 2-D relative velocity in such texts seem to be the motion of airplanes/blimps flying in the presence of wind or the conceptually identical cases of boats/rafts piloted across rivers/streams, including the effects of currents. These and similar cases are rather removed from the everyday experience of some students, and the use of simple lecture demonstrations to illustrate these concepts can be quite useful. For example, the motion of a simple toy "wind-up" car moving at constant speed across a horizontal tabletop, with a plastic sheet underneath providing the "moving frame of reference," can illustrate many aspects of such problems, including the need to "point" the plane/boat in an appropriate direction, just as illustrated in many textbook figures. On the other hand, it is also useful if students can directly experience concepts for themselves, especially in a kinesthetic manner, but there are seemingly far fewer human-sized lecture demonstrations on this topic. In this paper, we will point out one such example which might well be just a short drive away.

Coordinates in relativistic Hamiltonian mechanics

International Nuclear Information System (INIS)

Sokolov, S.N.

1984-01-01

The physical (covariant and measurable) coordinates of free particles and covariant coordinates of the center of inertia are found for three main forms of relativistic dynamics. In the point form of dynamics, the covariant coordinates of two directly interacting particles are found, and the equations of motion are brought to the explicitly covariant form. These equations are generalized to the case of interaction with an external electromagnetic field

Quasi-adiabatic motion of energetic particles in a dipole magnetic field

International Nuclear Information System (INIS)

Il'in, V.D.; Kuznetsov, S.N.; Yushkov, B.Yu.

1992-01-01

A moving coordinate system for a dipole magnetic field, in which reversible variations of magnetic moment for the range of obvious violations of adiabatic conditions are absent, and the description of magnetic moment violations is relatively simple, is considered. Constructing of a coordinate system, features of the central trajectory, determining its motion, the application range, the main application field and consequences are discussed. 11 refs.; 3 figs

The effect on organizational change on relational coordination – a multi case study

DEFF Research Database (Denmark)

Edwards, Kasper; Lundstrøm, Sanne Lykke

2014-01-01

This study presents results from an original empirical study of 11 organizational change projects in different wards at two Danish hospitals. The purpose of the study was to study was to study changes in relation coordination as a consequence of organizational change. We measured relational...... coordination before and after the organizational change using the 7 question relational coordination questionnaire. A group of employees were interviewed after the change project to uncover the nature and extent of the changes. We find that organizations’ relational coordination score change very little – even...... for organizational change that introduces new work relations and new processes....

The 50s cliff: a decline in perceptuo-motor learning, not a deficit in visual motion perception.

Science.gov (United States)

Ren, Jie; Huang, Shaochen; Zhang, Jiancheng; Zhu, Qin; Wilson, Andrew D; Snapp-Childs, Winona; Bingham, Geoffrey P

2015-01-01

Previously, we measured perceptuo-motor learning rates across the lifespan and found a sudden drop in learning rates between ages 50 and 60, called the "50s cliff." The task was a unimanual visual rhythmic coordination task in which participants used a joystick to oscillate one dot in a display in coordination with another dot oscillated by a computer. Participants learned to produce a coordination with a 90° relative phase relation between the dots. Learning rates for participants over 60 were half those of younger participants. Given existing evidence for visual motion perception deficits in people over 60 and the role of visual motion perception in the coordination task, it remained unclear whether the 50s cliff reflected onset of this deficit or a genuine decline in perceptuo-motor learning. The current work addressed this question. Two groups of 12 participants in each of four age ranges (20s, 50s, 60s, 70s) learned to perform a bimanual coordination of 90° relative phase. One group trained with only haptic information and the other group with both haptic and visual information about relative phase. Both groups were tested in both information conditions at baseline and post-test. If the 50s cliff was caused by an age dependent deficit in visual motion perception, then older participants in the visual group should have exhibited less learning than those in the haptic group, which should not exhibit the 50s cliff, and older participants in both groups should have performed less well when tested with visual information. Neither of these expectations was confirmed by the results, so we concluded that the 50s cliff reflects a genuine decline in perceptuo-motor learning with aging, not the onset of a deficit in visual motion perception.

Distributed Submodular Minimization And Motion Coordination Over Discrete State Space

KAUST Repository

Jaleel, Hassan

2017-09-21

Submodular set-functions are extensively used in large-scale combinatorial optimization problems arising in complex networks and machine learning. While there has been significant interest in distributed formulations of convex optimization, distributed minimization of submodular functions has not received significant attention. Thus, our main contribution is a framework for minimizing submodular functions in a distributed manner. The proposed framework is based on the ideas of Lovasz extension of submodular functions and distributed optimization of convex functions. The framework exploits a fundamental property of submodularity that the Lovasz extension of a submodular function is a convex function and can be computed efficiently. Moreover, a minimizer of a submodular function can be computed by computing the minimizer of its Lovasz extension. In the proposed framework, we employ a consensus based distributed optimization algorithm to minimize set-valued submodular functions as well as general submodular functions defined over set products. We also identify distributed motion coordination in multiagent systems as a new application domain for submodular function minimization. For demonstrating key ideas of the proposed framework, we select a complex setup of the capture the flag game, which offers a variety of challenges relevant to multiagent system. We formulate the problem as a submodular minimization problem and verify through extensive simulations that the proposed framework results in feasible policies for the agents.

Multiple spacecraft configuration designs for coordinated flight missions

Science.gov (United States)

Fumenti, Federico; Theil, Stephan

2018-06-01

Coordinated flight allows the replacement of a single monolithic spacecraft with multiple smaller ones, based on the principle of distributed systems. According to the mission objectives and to ensure a safe relative motion, constraints on the relative distances need to be satisfied. Initially, differential perturbations are limited by proper orbit design. Then, the induced differential drifts can be properly handled through corrective maneuvers. In this work, several designs are surveyed, defining the initial configuration of a group of spacecraft while counteracting the differential perturbations. For each of the investigated designs, focus is placed upon the number of deployable spacecraft and on the possibility to ensure safe relative motion through station keeping of the initial configuration, with particular attention to the required Δ V budget and the constraints violations.

Combining coordination of motion actuators with driver steering interaction.

Science.gov (United States)

Tagesson, Kristoffer; Laine, Leo; Jacobson, Bengt

2015-01-01

A new method is suggested for coordination of vehicle motion actuators; where driver feedback and capabilities become natural elements in the prioritization. The method is using a weighted least squares control allocation formulation, where driver characteristics can be added as virtual force constraints. The approach is in particular suitable for heavy commercial vehicles that in general are over actuated. The method is applied, in a specific use case, by running a simulation of a truck applying automatic braking on a split friction surface. Here the required driver steering angle, to maintain the intended direction, is limited by a constant threshold. This constant is automatically accounted for when balancing actuator usage in the method. Simulation results show that the actual required driver steering angle can be expected to match the set constant well. Furthermore, the stopping distance is very much affected by this set capability of the driver to handle the lateral disturbance, as expected. In general the capability of the driver to handle disturbances should be estimated in real-time, considering driver mental state. By using the method it will then be possible to estimate e.g. stopping distance implied from this. The setup has the potential of even shortening the stopping distance, when the driver is estimated as active, this compared to currently available systems. The approach is feasible for real-time applications and requires only measurable vehicle quantities for parameterization. Examples of other suitable applications in scope of the method would be electronic stability control, lateral stability control at launch and optimal cornering arbitration.

A 3D motion planning framework for snake robots

OpenAIRE

Liljebäck, Pål; Pettersen, Kristin Ytterstad; Stavdahl, Øyvind; Gravdahl, Jan Tommy

2014-01-01

- Author's postprint This paper presents a motion planning framework for three-dimensional body shape control of snake robots. Whereas conventional motion planning approaches define the body shape of snake robots in terms of their individual joint angles, the proposed framework allows the body shape to be specified in terms of Cartesian coordinates in the environment of the robot. This approach simplifies motion planning since Cartesian coordinates are more intuitively mapped to the overal...

The difference between the perception of absolute and relative motion: A reaction time study

NARCIS (Netherlands)

J.B.J. Smeets (Jeroen); E. Brenner (Eli)

1994-01-01

textabstractWe used a reaction-time paradigm to examine the extent to which motion detection depends on relative motion. In the absence of relative motion, the responses could be described by a simple model based on the detection of a fixed change in position. If relative motion was present, the

Impact of relational coordination on staff and patient outcomes in outpatient surgical clinics.

Science.gov (United States)

Gittell, Jody Hoffer; Logan, Caroline; Cronenwett, Jack; Foster, Tina C; Freeman, Richard; Godfrey, Marjorie; Vidal, Dale Collins

2018-01-05

Pressures are increasing for clinicians to provide high-quality, efficient care, leading to increased concerns about staff burnout. This study asks whether staff well-being can be achieved in ways that are also beneficial for the patient's experience of care. It explores whether relational coordination can contribute to both staff well-being and patient satisfaction in outpatient surgical clinics where time constraints paired with high needs for information transfer increase both the need for and the challenge of achieving timely and accurate communication. We studied relational coordination among surgeons, nurses, residents, administrators, technicians, and secretaries in 11 outpatient surgical clinics. Data were combined from a staff and a patient survey to conduct a cross-sectional study. Data were analyzed using ordinary least squares and random effects regression models. Relational coordination among all workgroups was significantly associated with staff outcomes, including job satisfaction, work engagement, and burnout. Relational coordination was also significantly associated with patients' satisfaction with staff and their overall visit, though the association between relational coordination and patients' satisfaction with their providers did not reach statistical significance. Even when patient-staff interactions are relatively brief, as in outpatient settings, high levels of relational coordination among interdependent workgroups contribute to positive outcomes for both staff and patients, and low levels tend to have the opposite effect. Clinical leaders can increase the expectation of positive outcomes for both staff and their patients by implementing interventions to strengthen relational coordination.

MARS, a Multi-Agent System for Assessing Rowers’ Coordination via Motion-Based Stigmergy

Directory of Open Access Journals (Sweden)

Mario G. C. A. Cimino

2013-09-01

Full Text Available A crucial aspect in rowing is having a synchronized, highly-efficient stroke. This is very difficult to obtain, due to the many interacting factors that each rower of the crew must perceive. Having a system that monitors and represents the crew coordination would be of great help to the coach during training sessions. In the literature, some methods already employ wireless sensors for capturing motion patterns that affect rowing performance. A challenging problem is to support the coach’s decisions at his same level of knowledge, using a limited number of sensors and avoiding the complexity of the biomechanical analysis of human movements. In this paper, we present a multi-agent information-processing system for on-water measuring of both the overall crew asynchrony and the individual rower asynchrony towards the crew. More specifically, in the system, the first level of processing is managed by marking agents, which release marks in a sensing space, according to the rowers’ motion. The accumulation of marks enables a stigmergic cooperation mechanism, generating collective marks, i.e., short-term memory structures in the sensing space. At the second level of processing, information provided by marks is observed by similarity agents, which associate a similarity degree with respect to optimal marks. Finally, the third level is managed by granulation agents, which extract asynchrony indicators for different purposes. The effectiveness of the system has been experimented on real-world scenarios. The study includes the problem statement and its characterization in the literature, as well as the proposed solving approach and initial experimental setting.

Development of a universal measure of quadrupedal forelimb-hindlimb coordination using digital motion capture and computerised analysis

Directory of Open Access Journals (Sweden)

Jeffery Nick D

2007-09-01

Full Text Available Abstract Background Clinical spinal cord injury in domestic dogs provides a model population in which to test the efficacy of putative therapeutic interventions for human spinal cord injury. To achieve this potential a robust method of functional analysis is required so that statistical comparison of numerical data derived from treated and control animals can be achieved. Results In this study we describe the use of digital motion capture equipment combined with mathematical analysis to derive a simple quantitative parameter – 'the mean diagonal coupling interval' – to describe coordination between forelimb and hindlimb movement. In normal dogs this parameter is independent of size, conformation, speed of walking or gait pattern. We show here that mean diagonal coupling interval is highly sensitive to alterations in forelimb-hindlimb coordination in dogs that have suffered spinal cord injury, and can be accurately quantified, but is unaffected by orthopaedic perturbations of gait. Conclusion Mean diagonal coupling interval is an easily derived, highly robust measurement that provides an ideal method to compare the functional effect of therapeutic interventions after spinal cord injury in quadrupeds.

Equations of motion in phase space

International Nuclear Information System (INIS)

Broucke, R.

1979-01-01

The article gives a general review of methods of constructing equations of motion of a classical dynamical system. The emphasis is however on the linear Lagrangian in phase space and the corresponding form of Pfaff's equations of motion. A detailed examination of the problem of changes of variables in phase space is first given. It is shown that the Linear Lagrangian theory falls very naturally out of the classical quadratic Lagrangian theory; we do this with the use of the well-known Lagrange multiplier method. Another important result is obtained very naturally as a by-product of this analysis. If the most general set of 2n variables (coordinates in phase space) is used, the coefficients of the equations of motion are the Poisson Brackets of these variables. This is therefore the natural way of introducing not only Poisson Brackets in Dynamics formulations but also the associated Lie Algebras and their important properties and consequences. We give then several examples to illustrate the first-order equations of motion and their simplicity in relation to general changes of variables. The first few examples are elementary (the harmonic Oscillator) while the last one concerns the motion of a rigid body about a fixed point. In the next three sections we treat the first-order equations of motion as derived from a Linear differential form, sometimes called Birkhoff's equations. We insist on the generality of the equations and especially on the unity of the space-time concept: the time t and the coordinates are here completely identical variables, without any privilege to t. We give a brief review of Cartan's 2-form and the corresponding equations of motion. As an illustration the standard equations of aircraft flight in a vertical plane are derived from Cartan's exterior differential 2-form. Finally we mention in the last section the differential forms that were proposed by Gallissot for the derivation of equations of motion

Method for Collision Avoidance Motion Coordination of Multiple Mobile Robots Using Central Observation

Energy Technology Data Exchange (ETDEWEB)

Ko, N.Y.; Seo, D.J. [Chosun University, Kwangju (Korea)

2003-04-01

This paper presents a new method driving multiple robots to their goal position without collision. Each robot adjusts its motion based on the information on the goal locations, velocity, and position of the robot and the velocity and position of the other robots. To consider the movement of the robots in a work area, we adopt the concept of avoidability measure. The avoidability measure figures the degree of how easily a robot can avoid other robots considering the following factors: the distance from the robot to the other robots, velocity of the robot and the other robots. To implement the concept in moving robot avoidance, relative distance between the robots is derived. Our method combines the relative distance with an artificial potential field method. The proposed method is simulated for several cases. The results show that the proposed method steers robots to open space anticipating the approach of other robots. In contrast, the usual potential field method sometimes fails preventing collision or causes hasty motion, because it initiates avoidance motion later than the proposed method. The proposed method can be used to move robots in a robot soccer team to their appropriate position without collision as fast as possible. (author). 21 refs., 10 figs., 13 tabs.

Shaking Takete and Flowing Maluma. Non-Sense Words Are Associated with Motion Patterns.

Directory of Open Access Journals (Sweden)

Markus Koppensteiner

Full Text Available People assign the artificial words takete and kiki to spiky, angular figures and the artificial words maluma and bouba to rounded figures. We examined whether such a cross-modal correspondence could also be found for human body motion. We transferred the body movements of speakers onto two-dimensional coordinates and created animated stick-figures based on this data. Then we invited people to judge these stimuli using the words takete-maluma, bouba-kiki, and several verbal descriptors that served as measures of angularity/smoothness. In addition to this we extracted the quantity of motion, the velocity of motion and the average angle between motion vectors from the coordinate data. Judgments of takete (and kiki were related to verbal descriptors of angularity, a high quantity of motion, high velocity and sharper angles. Judgments of maluma (or bouba were related to smooth movements, a low velocity, a lower quantity of motion and blunter angles. A forced-choice experiment during which we presented subsets with low and high rankers on our motion measures revealed that people preferably assigned stimuli displaying fast movements with sharp angles in motion vectors to takete and stimuli displaying slow movements with blunter angles in motion vectors to maluma. Results indicated that body movements share features with information inherent in words such as takete and maluma and that people perceive the body movements of speakers on the level of changes in motion direction (e.g., body moves to the left and then back to the right. Follow-up studies are needed to clarify whether impressions of angularity and smoothness have similar communicative values across different modalities and how this affects social judgments and person perception.

Shaking Takete and Flowing Maluma. Non-Sense Words Are Associated with Motion Patterns.

Science.gov (United States)

Koppensteiner, Markus; Stephan, Pia; Jäschke, Johannes Paul Michael

2016-01-01

People assign the artificial words takete and kiki to spiky, angular figures and the artificial words maluma and bouba to rounded figures. We examined whether such a cross-modal correspondence could also be found for human body motion. We transferred the body movements of speakers onto two-dimensional coordinates and created animated stick-figures based on this data. Then we invited people to judge these stimuli using the words takete-maluma, bouba-kiki, and several verbal descriptors that served as measures of angularity/smoothness. In addition to this we extracted the quantity of motion, the velocity of motion and the average angle between motion vectors from the coordinate data. Judgments of takete (and kiki) were related to verbal descriptors of angularity, a high quantity of motion, high velocity and sharper angles. Judgments of maluma (or bouba) were related to smooth movements, a low velocity, a lower quantity of motion and blunter angles. A forced-choice experiment during which we presented subsets with low and high rankers on our motion measures revealed that people preferably assigned stimuli displaying fast movements with sharp angles in motion vectors to takete and stimuli displaying slow movements with blunter angles in motion vectors to maluma. Results indicated that body movements share features with information inherent in words such as takete and maluma and that people perceive the body movements of speakers on the level of changes in motion direction (e.g., body moves to the left and then back to the right). Follow-up studies are needed to clarify whether impressions of angularity and smoothness have similar communicative values across different modalities and how this affects social judgments and person perception.

Effect of task-related continuous auditory feedback during learning of tracking motion exercises

Directory of Open Access Journals (Sweden)

Rosati Giulio

2012-10-01

Full Text Available Abstract Background This paper presents the results of a set of experiments in which we used continuous auditory feedback to augment motor training exercises. This feedback modality is mostly underexploited in current robotic rehabilitation systems, which usually implement only very basic auditory interfaces. Our hypothesis is that properly designed continuous auditory feedback could be used to represent temporal and spatial information that could in turn, improve performance and motor learning. Methods We implemented three different experiments on healthy subjects, who were asked to track a target on a screen by moving an input device (controller with their hand. Different visual and auditory feedback modalities were envisaged. The first experiment investigated whether continuous task-related auditory feedback can help improve performance to a greater extent than error-related audio feedback, or visual feedback alone. In the second experiment we used sensory substitution to compare different types of auditory feedback with equivalent visual feedback, in order to find out whether mapping the same information on a different sensory channel (the visual channel yielded comparable effects with those gained in the first experiment. The final experiment applied a continuously changing visuomotor transformation between the controller and the screen and mapped kinematic information, computed in either coordinate system (controller or video, to the audio channel, in order to investigate which information was more relevant to the user. Results Task-related audio feedback significantly improved performance with respect to visual feedback alone, whilst error-related feedback did not. Secondly, performance in audio tasks was significantly better with respect to the equivalent sensory-substituted visual tasks. Finally, with respect to visual feedback alone, video-task-related sound feedback decreased the tracking error during the learning of a novel

Determination of proper motions in the Pleiades cluster

Science.gov (United States)

Schilbach, E.

1991-04-01

For 458 stars in the Pleiades field from the catalog of Eichhorn et al. (1970) proper motions were derived on Tautenburg and CERGA Schmidt telescope plates measured with the automated measuring machine MAMA in Paris. The catalog positions were considered as first epoch coordinates with an epoch difference of ca. 33 years to the observations. The results show good coincidence of proper motions derived with both Schmidt telescopes within the error bars. Comparison with proper motions determined by Vasilevskis et al. (1979) displays some significant differences but no systematic effects depending on plate coordinates or magnitudes could be found. An accuracy of 0.3 arcsec/100a for one proper motion component was estimated. According to the criterion of common proper motion 34 new cluster members were identified.

Relational coordination is associated with productivity in general practice: a survey and register based study

DEFF Research Database (Denmark)

Lundstrøm, Sanne Lykke; Edwards, Kasper; Reventlow, Susanne

2014-01-01

In this paper we investigate the association between relational coordination among the practice team in general practice and number of consultations performed in a general practice per staff, i.e. a proxy of productivity. We measured relational coordination using the Relational Coordination Survey...... and combined the results with register data. We found that relational coordination was statistically significant associated with number of consultation per staff per year. We later divided consultations in to three types: Face-to-face, Email and phone consultations. We found a statistically significant...... associating between relational coordination and with number of face-to-face consultation per staff per year....

Motion of a spinning test particle in Vaidya's radiating metric

International Nuclear Information System (INIS)

Carmeli, M.; Charach, C.; Kaye, M.

1977-01-01

The motion of a spinning test particle in Vaidya's gravitational field is considered in the framework of Papapetrou's equations of motion. Use is made of the supplementary condition S/sup μ//sup u/ = 0, where u is the retarded Schwarzschild time coordinate. We derive the equations for the dynamical variables, and consider the conservation laws, that follow from the equations of motion. Particular cases of motion are also discussed and additional first integrals corresponding to these cases are found. Some of the new extra integrals are related to the Casimir operators of the Poincare group. It is found that under special conditions on the spin tensor components the particle follows a geodesic. Motion of the spinning test particle in the Schwarzschild field is considered as one of the particular cases

Singular perturbations of manifolds, with applications to the problem of motion in general relativity

International Nuclear Information System (INIS)

Kates, R.E.

1979-01-01

This thesis shows that a small body with possibly strong internal gravity moves through an empty region of a curved, and not necessarily asymptotically flat, external spacetime on an approximate geodesic. By approximate geodesic, the following is meant: Suppose the ratio epsilon = m/L 1 - where m is the body's mass and L is a curvature reference length of the external field - is a small parameter. Then the body's worldline deviates from a geodesic only by distances of at most THETA(epsilon) L over times of order L. The worldline is calculated directly from the Einstein field equation using a singular perturbation technique that has been generalized from the method of matched asymptotic expansions. The need for singular perturbation techniques has long been appreciated in fluid mechanics, where they are now standard procedure in problems in which the straightforward expansion in powers of a small parameter fails to give a correct qualitative picture. In part I of this thesis, singular perturbations on manifolds are formulated in a coordinate-free way suitable for treating problems in general relativity and other field theories. Most importantly for this thesis, the coordinate-free formulation of singular perturbations given in part I is essential for treatment of the problem of motion in part II

Measures and Relative Motions of Some Mostly F. G. W. Struve Doubles

Science.gov (United States)

Wiley, E. O.

2012-04-01

Measures of 59 pairs of double stars with long observational histories using "lucky imaging" techniques are reported. Relative motions of 59 pairs are investigated using histories of observation, scatter plots of relative motion, ordinary least-squares (OLS) and total proper motion analyses performed in "R," an open source programming language. A scatter plot of the coefficient of determinations derived from the OLS y|epoch and OLS x|epoch clearly separates common proper motion pairs from optical pairs and what are termed "long-period binary candidates." Differences in proper motion separate optical pairs from long-term binary candidates. An Appendix is provided that details how to use known rectilinear pairs as calibration pairs for the program REDUC.

Learning alternative movement coordination patterns using reinforcement feedback.

Science.gov (United States)

Lin, Tzu-Hsiang; Denomme, Amber; Ranganathan, Rajiv

2018-05-01

One of the characteristic features of the human motor system is redundancy-i.e., the ability to achieve a given task outcome using multiple coordination patterns. However, once participants settle on using a specific coordination pattern, the process of learning to use a new alternative coordination pattern to perform the same task is still poorly understood. Here, using two experiments, we examined this process of how participants shift from one coordination pattern to another using different reinforcement schedules. Participants performed a virtual reaching task, where they moved a cursor to different targets positioned on the screen. Our goal was to make participants use a coordination pattern with greater trunk motion, and to this end, we provided reinforcement by making the cursor disappear if the trunk motion during the reach did not cross a specified threshold value. In Experiment 1, we compared two reinforcement schedules in two groups of participants-an abrupt group, where the threshold was introduced immediately at the beginning of practice; and a gradual group, where the threshold was introduced gradually with practice. Results showed that both abrupt and gradual groups were effective in shifting their coordination patterns to involve greater trunk motion, but the abrupt group showed greater retention when the reinforcement was removed. In Experiment 2, we examined the basis of this advantage in the abrupt group using two additional control groups. Results showed that the advantage of the abrupt group was because of a greater number of practice trials with the desired coordination pattern. Overall, these results show that reinforcement can be successfully used to shift coordination patterns, which has potential in the rehabilitation of movement disorders.

Improving pulse oximetry accuracy by removing motion artifacts from photoplethysmograms using relative sensor motion: a preliminary study

NARCIS (Netherlands)

Wijshoff, R.W.C.G.R.; Mischi, M.; Woerlee, P.H.; Aarts, R.M.; Van Huffel, S.; Naelaers, G.; Caicedo, A.; Bruley, D.F.; Harrison, D.K.

2013-01-01

To expand applicability of pulse oximetry in low-acuity ambulatory settings, the impact of motion on extracted parameters as saturation (SpO2) and pulse rate (PR) needs to be reduced. We hypothesized that sensor motion relative to the skin can be used as an artifact reference in a correlation

Analysing collaboration among HIV agencies through combining network theory and relational coordination.

Science.gov (United States)

Khosla, Nidhi; Marsteller, Jill Ann; Hsu, Yea Jen; Elliott, David L

2016-02-01

Agencies with different foci (e.g. nutrition, social, medical, housing) serve people living with HIV (PLHIV). Serving needs of PLHIV comprehensively requires a high degree of coordination among agencies which often benefits from more frequent communication. We combined Social Network theory and Relational Coordination theory to study coordination among HIV agencies in Baltimore. Social Network theory implies that actors (e.g., HIV agencies) establish linkages amongst themselves in order to access resources (e.g., information). Relational Coordination theory suggests that high quality coordination among agencies or teams relies on the seven dimensions of frequency, timeliness and accuracy of communication, problem-solving communication, knowledge of agencies' work, mutual respect and shared goals. We collected data on frequency of contact from 57 agencies using a roster method. Response options were ordinal ranging from 'not at all' to 'daily'. We analyzed data using social network measures. Next, we selected agencies with which at least one-third of the sample reported monthly or more frequent interaction. This yielded 11 agencies whom we surveyed on seven relational coordination dimensions with questions scored on a Likert scale of 1-5. Network density, defined as the proportion of existing connections to all possible connections, was 20% when considering monthly or higher interaction. Relational coordination scores from individual agencies to others ranged between 1.17 and 5.00 (maximum possible score 5). The average scores for different dimensions across all agencies ranged between 3.30 and 4.00. Shared goals (4.00) and mutual respect (3.91) scores were highest, while scores such as knowledge of each other's work and problem-solving communication were relatively lower. Combining theoretically driven analyses in this manner offers an innovative way to provide a comprehensive picture of inter-agency coordination and the quality of exchange that underlies

Exit from Synchrony in Joint Improvised Motion.

Directory of Open Access Journals (Sweden)

Assi Dahan

Full Text Available Motion synchrony correlates with effective and well-rated human interaction. However, people do not remain locked in synchrony; Instead, they repeatedly enter and exit synchrony. In many important interactions, such as therapy, marriage and parent-infant communication, it is the ability to exit and then re-enter synchrony that is thought to build strong relationship. The phenomenon of entry into zero-phase synchrony is well-studied experimentally and in terms of mathematical modeling. In contrast, exit-from-synchrony is under-studied. Here, we focus on human motion coordination, and examine the exit-from-synchrony phenomenon using experimental data from the mirror game paradigm, in which people perform joint improvised motion, and from human tracking of computer-generated stimuli. We present a mathematical mechanism that captures aspects of exit-from-synchrony in human motion. The mechanism adds a random motion component when the accumulated velocity error between the players is small. We introduce this mechanism to several models for human coordinated motion, including the widely studied HKB model, and the predictor-corrector model of Noy, Dekel and Alon. In all models, the new mechanism produces realistic simulated behavior when compared to experimental data from the mirror game and from tracking of computer generated stimuli, including repeated entry and exit from zero-phase synchrony that generates a complexity of motion similar to that of human players. We hope that these results can inform future research on exit-from-synchrony, to better understand the dynamics of coordinated action of people and to enhance human-computer and human-robot interaction.

Robot motion control in mobile environment

Institute of Scientific and Technical Information of China (English)

Iliya V Miroshnik; HUANG Xian-lin(黄显林); HE Jie(贺杰)

2003-01-01

With the problem of robot motion control in dynamic environment represented by mobile obstacles,working pieces and external mechanisms considered, a relevant control actions design procedure has been pro-posed to provide coordination of robot motions with respect to the moving external objects so that an extension ofrobot spatial motion techniques and active robotic strategies based on approaches of nonlinear control theory canbe achieved.

Engineering uses of physics-based ground motion simulations

Science.gov (United States)

Baker, Jack W.; Luco, Nicolas; Abrahamson, Norman A.; Graves, Robert W.; Maechling, Phillip J.; Olsen, Kim B.

2014-01-01

This paper summarizes validation methodologies focused on enabling ground motion simulations to be used with confidence in engineering applications such as seismic hazard analysis and dynmaic analysis of structural and geotechnical systems. Numberical simullation of ground motion from large erthquakes, utilizing physics-based models of earthquake rupture and wave propagation, is an area of active research in the earth science community. Refinement and validatoin of these models require collaboration between earthquake scientists and engineering users, and testing/rating methodolgies for simulated ground motions to be used with confidence in engineering applications. This paper provides an introduction to this field and an overview of current research activities being coordinated by the Souther California Earthquake Center (SCEC). These activities are related both to advancing the science and computational infrastructure needed to produce ground motion simulations, as well as to engineering validation procedures. Current research areas and anticipated future achievements are also discussed.

Relative Motion of the WDS 05110+3203 STF 648 System, With a Protocol for Calculating Relative Motion

Science.gov (United States)

Wiley, E. O.

2010-07-01

Relative motion studies of visual double stars can be investigated using least squares regression techniques and readily accessible programs such as Microsoft Excel and a calculator. Optical pairs differ from physical pairs under most geometries in both their simple scatter plots and their regression models. A step-by-step protocol for estimating the rectilinear elements of an optical pair is presented. The characteristics of physical pairs using these techniques are discussed.

Single-particle motion in large-amplitude quadrupole shape transition

International Nuclear Information System (INIS)

Yamada, Kazuya

1991-01-01

The microscopic structure of the single-particle motion for the spherical-deformed transitional nuclei is analysed by using the self-consistent collective-coordinate method (SCC method). The single-particle motion in the moving-frame of reference called the collective vibrating coordinate frame is introduced by the generalized Bogoliubov transformation depending on the collective coordinate. The numerical calculations of the single-particle (quasi-particle) energy level diagrams and their occupation probabilities for the static deformation are carried out for the Sm isotopes. A clear change of the single-particle distribution structure appears in the course of deformation. (author)

Generalized transformations and coordinates for static spherically symmetric general relativity

Science.gov (United States)

Hill, James M.; O'Leary, Joseph

2018-04-01

We examine a static, spherically symmetric solution of the empty space field equations of general relativity with a non-orthogonal line element which gives rise to an opportunity that does not occur in the standard derivations of the Schwarzschild solution. In these derivations, convenient coordinate transformations and dynamical assumptions inevitably lead to the Schwarzschild solution. By relaxing these conditions, a new solution possibility arises and the resulting formalism embraces the Schwarzschild solution as a special case. The new solution avoids the coordinate singularity associated with the Schwarzschild solution and is achieved by obtaining a more suitable coordinate chart. The solution embodies two arbitrary constants, one of which can be identified as the Newtonian gravitational potential using the weak field limit. The additional arbitrary constant gives rise to a situation that allows for generalizations of the Eddington-Finkelstein transformation and the Kruskal-Szekeres coordinates.

Generalized transformations and coordinates for static spherically symmetric general relativity.

Science.gov (United States)

Hill, James M; O'Leary, Joseph

2018-04-01

We examine a static, spherically symmetric solution of the empty space field equations of general relativity with a non-orthogonal line element which gives rise to an opportunity that does not occur in the standard derivations of the Schwarzschild solution. In these derivations, convenient coordinate transformations and dynamical assumptions inevitably lead to the Schwarzschild solution. By relaxing these conditions, a new solution possibility arises and the resulting formalism embraces the Schwarzschild solution as a special case. The new solution avoids the coordinate singularity associated with the Schwarzschild solution and is achieved by obtaining a more suitable coordinate chart. The solution embodies two arbitrary constants, one of which can be identified as the Newtonian gravitational potential using the weak field limit. The additional arbitrary constant gives rise to a situation that allows for generalizations of the Eddington-Finkelstein transformation and the Kruskal-Szekeres coordinates.

Influence of Visual Motion, Suggestion, and Illusory Motion on Self-Motion Perception in the Horizontal Plane.

Directory of Open Access Journals (Sweden)

Steven David Rosenblatt

Full Text Available A moving visual field can induce the feeling of self-motion or vection. Illusory motion from static repeated asymmetric patterns creates a compelling visual motion stimulus, but it is unclear if such illusory motion can induce a feeling of self-motion or alter self-motion perception. In these experiments, human subjects reported the perceived direction of self-motion for sway translation and yaw rotation at the end of a period of viewing set visual stimuli coordinated with varying inertial stimuli. This tested the hypothesis that illusory visual motion would influence self-motion perception in the horizontal plane. Trials were arranged into 5 blocks based on stimulus type: moving star field with yaw rotation, moving star field with sway translation, illusory motion with yaw, illusory motion with sway, and static arrows with sway. Static arrows were used to evaluate the effect of cognitive suggestion on self-motion perception. Each trial had a control condition; the illusory motion controls were altered versions of the experimental image, which removed the illusory motion effect. For the moving visual stimulus, controls were carried out in a dark room. With the arrow visual stimulus, controls were a gray screen. In blocks containing a visual stimulus there was an 8s viewing interval with the inertial stimulus occurring over the final 1s. This allowed measurement of the visual illusion perception using objective methods. When no visual stimulus was present, only the 1s motion stimulus was presented. Eight women and five men (mean age 37 participated. To assess for a shift in self-motion perception, the effect of each visual stimulus on the self-motion stimulus (cm/s at which subjects were equally likely to report motion in either direction was measured. Significant effects were seen for moving star fields for both translation (p = 0.001 and rotation (p0.1 for both. Thus, although a true moving visual field can induce self-motion, results of this

Ground Motion Relations While TBM Drilling in Unconsolidated Sediments

Science.gov (United States)

Grund, Michael; Ritter, Joachim R. R.; Gehrig, Manuel

2016-05-01

The induced ground motions due to the tunnel boring machine (TBM), which has been used for the drilling of the urban metro tunnel in Karlsruhe (SW Germany), has been studied using the continuous recordings of seven seismological monitoring stations. The drilling has been undertaken in unconsolidated sediments of the Rhine River system, relatively close to the surface at 6-20 m depth and in the vicinity of many historic buildings. Compared to the reference values of DIN 4150-3 (1-80 Hz), no exceedance of the recommended peak ground velocity (PGV) limits (3-5 mm/s) was observed at the single recording site locations on building basements during the observation period between October 2014 and February 2015. Detailed analyses in the time and frequency domains helped with the detection of the sources of several specific shaking signals in the recorded time series and with the comparison of the aforementioned TBM-induced signals. The amplitude analysis allowed for the determination of a PGV attenuation relation (quality factor Q ~ 30-50) and the comparison of the TBM-induced ground motion with other artificially induced and natural ground motions of similar amplitudes.

Collective coordinates on symplectic manifolds

International Nuclear Information System (INIS)

Razumov, A.V.; Taranov, A.Yu.

1981-01-01

For an arbitrary Lie group of canonical transformations on a symplectic manifold collective coordinates are introduced. They describe a motion of the dynamical system as a whole under the group transformations. Some properties of Lie group of canonical transformations are considered [ru

Influence of Visual Motion, Suggestion, and Illusory Motion on Self-Motion Perception in the Horizontal Plane.

Science.gov (United States)

Rosenblatt, Steven David; Crane, Benjamin Thomas

2015-01-01

A moving visual field can induce the feeling of self-motion or vection. Illusory motion from static repeated asymmetric patterns creates a compelling visual motion stimulus, but it is unclear if such illusory motion can induce a feeling of self-motion or alter self-motion perception. In these experiments, human subjects reported the perceived direction of self-motion for sway translation and yaw rotation at the end of a period of viewing set visual stimuli coordinated with varying inertial stimuli. This tested the hypothesis that illusory visual motion would influence self-motion perception in the horizontal plane. Trials were arranged into 5 blocks based on stimulus type: moving star field with yaw rotation, moving star field with sway translation, illusory motion with yaw, illusory motion with sway, and static arrows with sway. Static arrows were used to evaluate the effect of cognitive suggestion on self-motion perception. Each trial had a control condition; the illusory motion controls were altered versions of the experimental image, which removed the illusory motion effect. For the moving visual stimulus, controls were carried out in a dark room. With the arrow visual stimulus, controls were a gray screen. In blocks containing a visual stimulus there was an 8s viewing interval with the inertial stimulus occurring over the final 1s. This allowed measurement of the visual illusion perception using objective methods. When no visual stimulus was present, only the 1s motion stimulus was presented. Eight women and five men (mean age 37) participated. To assess for a shift in self-motion perception, the effect of each visual stimulus on the self-motion stimulus (cm/s) at which subjects were equally likely to report motion in either direction was measured. Significant effects were seen for moving star fields for both translation (p = 0.001) and rotation (pperception was shifted in the direction consistent with the visual stimulus. Arrows had a small effect on self-motion

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

Science.gov (United States)

Franklin, Jerrold

2010-01-01

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

Features of projectile motion in the special theory of relativity

International Nuclear Information System (INIS)

Shahin, Ghassan Y

2006-01-01

A relativistic projectile motion in a vacuum is examined by means of elementary consequences of special relativity. Exact analytical expressions were found for the kinematics variables using basic mathematical tools. The trajectory equation was established and the area under the trajectory traversed by the relativistic projectile was determined. It was found that, unlike non-relativistic projectile motion, the launching angles that maximize both the horizontal range as well as the area under the trajectory are functions of the initial speed. It is anticipated that this paper will be consistent with the intuition of students and serve as a resource for further problems usually encountered in the special theory of relativity

Social forces for team coordination in ball possession game

Science.gov (United States)

Yokoyama, Keiko; Shima, Hiroyuki; Fujii, Keisuke; Tabuchi, Noriyuki; Yamamoto, Yuji

2018-02-01

Team coordination is a basic human behavioral trait observed in many real-life communities. To promote teamwork, it is important to cultivate social skills that elicit team coordination. In the present work, we consider which social skills are indispensable for individuals performing a ball possession game in soccer. We develop a simple social force model that describes the synchronized motion of offensive players. Comparing the simulation results with experimental observations, we uncovered that the cooperative social force, a measure of perception skill, has the most important role in reproducing the harmonized collective motion of experienced players in the task. We further developed an experimental tool that facilitates real players' perceptions of interpersonal distance, revealing that the tool improves novice players' motions as if the cooperative social force were imposed.

Lorentz contraction, Bell's spaceships and rigid body motion in special relativity

International Nuclear Information System (INIS)

Franklin, Jerrold

2010-01-01

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

Federal interagency radiation policy coordination

International Nuclear Information System (INIS)

Young, A.L.

1984-01-01

The author discusses Federal interagency radiation policy coordination. The Committee on Interagency Radiation Research and Policy Coordination (CIRRPC) is explained as being dedicated to the success and forward motion of enhanced radiation research and policy coordination. Both CIRRPC and the Science Panel are staffed with Federal employees. Their expertise includes many and various radiation disciplines including cytogenetics, dosimetry, epidemiology, genetics, health physics, nuclear medicine, radiology, radiation carcinogenesis, and risk assessment. Ten scientific and technical issues in their preliminary order are presented: radioepidemiological tables; de minimis radiation levels; radon progeny health effects; occupational exposure registry; measurement, recording, and control of radiation; food irradiation; use of radiation in science, industry, and medicine; nonionizing radiation; and remedial actions

Impact of Relational Coordination on Nurse Job Satisfaction, Work Engagement and Burnout: Achieving the Quadruple Aim.

Science.gov (United States)

Havens, Donna Sullivan; Gittell, Jody Hoffer; Vasey, Joseph

2018-03-01

To explore how relational coordination, known to enhance quality and efficiency outcomes for patients and hospitals, impacts direct care nurse outcomes such as burnout, work engagement, and job satisfaction, addressing the "Quadruple Aim," to improve the experience of providing care. Hospitals are complex organizations in which multiple providers work interdependently, under conditions of uncertainty and time constraints, to deliver safe quality care despite differences in specialization, training, and status. Relational coordination-communicating and relating for the purpose of task integration-is known to improve quality, safety, and efficiency under these conditions, but less is known about its impact on the well-being of direct care providers themselves. Surveys measuring relational coordination among nurses and other types of providers as well as job-related outcomes in 5 acute care community hospitals were completed by direct care RNs. Relational coordination was significantly related to increased job satisfaction, increased work engagement, and reduced burnout. Relational coordination contributes to the well-being of direct care nurses, addressing the Quadruple Aim by improving the experience of providing care.

Optimal coordination and control of posture and movements.

Science.gov (United States)

Johansson, Rolf; Fransson, Per-Anders; Magnusson, Måns

2009-01-01

This paper presents a theoretical model of stability and coordination of posture and locomotion, together with algorithms for continuous-time quadratic optimization of motion control. Explicit solutions to the Hamilton-Jacobi equation for optimal control of rigid-body motion are obtained by solving an algebraic matrix equation. The stability is investigated with Lyapunov function theory and it is shown that global asymptotic stability holds. It is also shown how optimal control and adaptive control may act in concert in the case of unknown or uncertain system parameters. The solution describes motion strategies of minimum effort and variance. The proposed optimal control is formulated to be suitable as a posture and movement model for experimental validation and verification. The combination of adaptive and optimal control makes this algorithm a candidate for coordination and control of functional neuromuscular stimulation as well as of prostheses. Validation examples with experimental data are provided.

Relative roughness controls on incipient sediment motion in steep channels

Science.gov (United States)

Prancevic, J.; Lamb, M. P.; Fuller, B. M.

2012-12-01

For over eight decades, researchers have noted an appreciable increase in the nondimensional shear stress (Shields number) at initiation of fluvial bedload transport with increasing bed slope. The precise cause of the trend, however, is obscured by the covariance of several factors with increased slope: a greater downstream component of the gravity acting on the grains and fluid, changes in bed morphology, increased grainsize relative to the channel width that may lead to grain bridging, and increased grainsize relative to flow depth (relative roughness) that may change flow hydraulics and particle buoyancy. Here, we report on ongoing laboratory experiments spanning a wide range of bed slopes (2% to 67%) designed to isolate these variables and determine the true cause of heightened critical Shields numbers on steep slopes. First, we eliminated bed morphology as a factor by using only planar beds. To investigate the effect of grain bridging, we used two different channel widths, representing width-to-grainsize ratios of 23:1 and 9:1. Finally, to separate the effects of slope from relative roughness, we compared incipient motion conditions for acrylic particles (submerged specific gravity of 0.15) to natural siliciclastic gravel (submerged specific gravity of 1.65). Different particle densities allowed us to explore incipient motion as a function of relative roughness, independent of channel slope, because lighter particles move at shallower flow depths than heavier ones of the same size. Results show that both materials exhibit a positive trend between bed slope and critical Shields number despite the existence of planar beds for all slopes. Furthermore, changing the grainsize-to-width ratio had a negligible effect on this trend. For all slopes, the critical Shields number for bedload transport was higher for the acrylic particles than for gravel, indicating that relative roughness has a strong control on incipient sediment motion independent of channel slope. These

Motion state analysis of space target based on optical cross section

Science.gov (United States)

Tian, Qichen; Li, Zhi; Xu, Can; Liu, Chenghao

2017-10-01

In order to solve the problem that the movement state analysis method of the space target based on OCS is not related to the real motion state. This paper proposes a method based on OCS for analyzing the state of space target motion. This paper first establish a three-dimensional model of real STSS satellite, then change the satellite's surface into element, and assign material to each panel according to the actual conditions of the satellite. This paper set up a motion scene according to the orbit parameters of STSS satellite in STK, and the motion states are set to three axis steady state and slowly rotating unstable state respectively. In these two states, the occlusion condition of the surface element is firstly determined, and the effective face element is selected. Then, the coordinates of the observation station and the solar coordinates in the satellite body coordinate system are input into the OCS calculation program, and the OCS variation curves of the three axis steady state and the slow rotating unstable state STSS satellite are obtained. Combining the satellite surface structure and the load situation, the OCS change curve of the three axis stabilized satellite is analyzed, and the conclude that the OCS curve fluctuates up and down when the sunlight is irradiated to the load area; By using Spectral analysis method, autocorrelation analysis and the cross residual method, the rotation speed of OCS satellite in slow rotating unstable state is analyzed, and the rotation speed of satellite is successfully reversed. By comparing the three methods, it is found that the cross residual method is more accurate.

Health-Related Physical Fitness in Dutch Children With Developmental Coordination Disorder

NARCIS (Netherlands)

van der Hoek, Frouwien D.; Stuive, Ilse; Reinders-Messelink, Heleen A.; Holty, Lian; de Blecourt, Alida C. E.; Maathuis, Carel G. B.; van Weert, Ellen

2012-01-01

Objective: To compare components of health-related physical fitness between Dutch children with clinically diagnosed developmental coordination disorder (DCD) and typically developing children (TDC), and to examine associations between motor performance problems and components of health-related

Motion Planning for a Direct Metal Deposition Rapid Prototyping System

Energy Technology Data Exchange (ETDEWEB)

AMES,ARLO L.; HENSINGER,DAVID M.; KUHLMANN,JOEL L.

1999-10-18

A motion planning strategy was developed and implemented to generate motion control instructions from solid model data for controlling a robotically driven solid free-form fabrication process. The planning strategy was tested using a PUMA type robot arm integrated into a LENS{trademark} (Laser Engineered Net Shape) system. Previous systems relied on a series of x, y, and z stages, to provide a minimal coordinated motion control capability. This limited the complexity of geometries that could be constructed. With the coordinated motion provided by a robotic arm, the system can produce three dimensional parts by ''writing'' material onto any face of existing material. The motion planning strategy relied on solid model geometry evaluation and exploited robotic positioning flexibility to allow the construction of geometrically complex parts. The integration of the robotic manipulator into the LENS{trademark} system was tested by producing metal parts directly from CAD models.

A Live-Time Relation: Motion Graphics meets Classical Music

DEFF Research Database (Denmark)

Steijn, Arthur

2014-01-01

, liveness and atmosphere. The design model will be a framework for both academic analytical studies as well as for designing time-based narratives and visual concepts involving motion graphics in spatial contexts. I focus on cases in which both pre-rendered, and live generated motion graphics are designed......In our digital age, we frequently meet fine examples of live performances of classical music with accompanying visuals. Yet, we find very little theoretical or analytical work on the relation between classical music and digital temporal visuals, nor on the process of creating them. In this paper, I...... present segments of my work toward a working model for the process of design of visuals and motion graphics applied in spatial contexts. I show how various design elements and components: line and shape, tone and colour, time and timing, rhythm and movement interact with conceptualizations of space...

de Sitter relativity in static charts

Energy Technology Data Exchange (ETDEWEB)

Cotaescu, Ion I. [West University of Timisoara, Timisoara (Romania)

2018-02-15

The relative geodesic motion in static (and spherically symmetric) local charts on the (1 + 3)-dimensional de Sitter spacetimes is studied in terms of conserved quantities. The Lorentzian isometries are derived, relating the coordinates of the local chart of a fixed observer with the coordinates of a mobile chart considered as the rest frame of a massive particle freely moving on a timelike geodesic. The time dilation and Lorentz contraction are discussed pointing out some notable features of the de Sitter relativity in static charts. (orig.)

Hamiltonian theory of guiding-center motion

Energy Technology Data Exchange (ETDEWEB)

Littlejohn, R.G.

1980-05-01

A Hamiltonian treatment of the guiding center problem is given which employs noncanonical coordinates in phase space. Separation of the unperturbed system from the perturbation is achieved by using a coordinate transformation suggested by a theorem of Darboux. As a model to illustrate the method, motion in the magnetic field B=B(x,y)z is studied. Lie transforms are used to carry out the perturbation expansion.

Hamiltonian theory of guiding-center motion

International Nuclear Information System (INIS)

Littlejohn, R.G.

1980-05-01

A Hamiltonian treatment of the guiding center problem is given which employs noncanonical coordinates in phase space. Separation of the unperturbed system from the perturbation is achieved by using a coordinate transformation suggested by a theorem of Darboux. As a model to illustrate the method, motion in the magnetic field B=B(x,y)z is studied. Lie transforms are used to carry out the perturbation expansion

The importance of multidisciplinary teamwork and team climate for relational coordination among teams delivering care to older patients.

Science.gov (United States)

Hartgerink, J M; Cramm, J M; Bakker, T J E M; van Eijsden, A M; Mackenbach, J P; Nieboer, A P

2014-04-01

To identify predictors of relational coordination among professionals delivering care to older patients. Relational coordination is known to enhance quality of care in hospitals. The underlying mechanisms, however, remain poorly understood. This cross-sectional study was part of a larger evaluation study examining the opportunity to prevent loss of function in older patients due to hospitalization in the Netherlands. This study was performed in spring 2010 among team members delivering care to older hospitalized patients (192 respondents; 44% response rate) in one hospital. Relational coordination was measured by the Relational Coordination survey; team climate by the Team Climate Inventory and questions were asked about participation in multidisciplinary team meetings and disciplines represented in these meetings. To account for the hierarchical structure, a multilevel analysis was performed. Correlation analysis revealed a positive relationship among being female, being a nurse and relational coordination; medical specialists showed a negative relationship. The number of disciplines represented during multidisciplinary team meetings and team climate were positively related with relational coordination. The multilevel analysis showed a positive relationship between the number of disciplines represented during multidisciplinary team meetings and team climate with relational coordination. The enhancement of team climate and attendance of diverse professionals during multidisciplinary team meetings are expected to improve relational coordination. Furthermore, this study underscores the importance of enhancing relational coordination between medical specialists and other professionals. © 2013 The Authors. Journal of Advanced Nursing published by John Wiley & Sons Ltd.

Relative Motion Modeling and Autonomous Navigation Accuracy

Science.gov (United States)

2016-11-15

74-79. [39] T. Carter and M. Humi, “Clohessy-Wiltshire Equations Modified to Include Quadratic Drag,” Journal of Guidance, Control and Dynamics...the effect of the absolute and differential effects of the equatorial bulge term, J2, in the linearized equations for the relative motion of...perturbation equations up to third-order used for separating the secular and periodic effects can be written as where , , , and are the Kamiltonians of

Effects of relational coordination among colleagues and span of control on work engagement among home-visiting nurses.

Science.gov (United States)

Naruse, Takashi; Sakai, Mahiro; Nagata, Satoko

2016-04-01

Home-visiting nursing agencies are required to foster staff nurse's work engagement; thus, the factors related to work engagement require identification. This study examined relational coordination among colleagues and agency span of control on the work engagement of home-visiting nurses. Cross-sectional data from 93 staff nurses in 31 home-visiting nursing agencies were collected via a survey and analyzed using mixed linear regression. There was no significant main effect of relational coordination among nurse colleagues on work engagement. In large agencies with a large span of control, relational coordination among nursing colleagues predicted work engagement. Nursing managers' relational coordination was found to be positively associated with staff nurse work engagement. Agency span of control is a moderating factor on the positive effect of relational coordination with nursing colleagues on staff nurse work engagement. © 2016 Japan Academy of Nursing Science.

SU-E-T-570: New Quality Assurance Method Using Motion Tracking for 6D Robotic Couches

International Nuclear Information System (INIS)

Cheon, W; Cho, J; Ahn, S; Han, Y; Choi, D

2015-01-01

Purpose: To accommodate geometrically accurate patient positioning, a robotic couch that is capable of 6-degrees of freedom has been introduced. However, conventional couch QA methods are not sufficient to enable the necessary accuracy of tests. Therefore, we have developed a camera based motion detection and geometry calibration system for couch QA. Methods: Employing a Visual-Tracking System (VTS, BonitaB10, Vicon, UK) which tracks infrared reflective(IR) markers, camera calibration was conducted using a 5.7 × 5.7 × 5.7 cm 3 cube attached with IR markers at each corner. After positioning a robotic-couch at the origin with the cube on the table top, 3D coordinates of the cube’s eight corners were acquired by VTS in the VTS coordinate system. Next, positions in reference coordinates (roomcoordinates) were assigned using the known relation between each point. Finally, camera calibration was completed by finding a transformation matrix between VTS and reference coordinate systems and by applying a pseudo inverse matrix method. After the calibration, the accuracy of linear and rotational motions as well as couch sagging could be measured by analyzing the continuously acquired data of the cube while the couch moves to a designated position. Accuracy of the developed software was verified through comparison with measurement data when using a Laser tracker (FARO, Lake Mary, USA) for a robotic-couch installed for proton therapy. Results: VTS system could track couch motion accurately and measured position in room-coordinates. The VTS measurements and Laser tracker data agreed within 1% of difference for linear and rotational motions. Also because the program analyzes motion in 3-Dimension, it can compute couch sagging. Conclusion: Developed QA system provides submillimeter/ degree accuracy which fulfills the high-end couch QA. This work was supported by the National Research Foundation of Korea funded by Ministry of Science, ICT & Future Planning. (2013M2A2A7043507

Technical note: validation of a motion analysis system for measuring the relative motion of the intermediate component of a tripolar total hip arthroplasty prosthesis.

Science.gov (United States)

Chen, Qingshan; Lazennec, Jean Yves; Guyen, Olivier; Kinbrum, Amy; Berry, Daniel J; An, Kai-Nan

2005-07-01

Tripolar total hip arthroplasty (THA) prosthesis had been suggested as a method to reduce the occurrence of hip dislocation and microseparation. Precisely measuring the motion of the intermediate component in vitro would provide fundamental knowledge for understanding its mechanism. The present study validates the accuracy and repeatability of a three-dimensional motion analysis system to quantitatively measure the relative motion of the intermediate component of tripolar total hip arthroplasty prostheses. Static and dynamic validations of the system were made by comparing the measurement to that of a potentiometer. Differences between the mean system-calculated angle and the angle measured by the potentiometer were within +/-1 degrees . The mean within-trial variability was less than 1 degrees . The mean slope was 0.9-1.02 for different angular velocities. The dynamic noise was within 1 degrees . The system was then applied to measure the relative motion of an eccentric THA prosthesis. The study shows that this motion analysis system provides an accurate and practical method for measuring the relative motion of the tripolar THA prosthesis in vitro, a necessary first step towards the understanding of its in vivo kinematics.

Motion of ionizing electric-field solitons in a bounded plasma

International Nuclear Information System (INIS)

Lagar'kov, A.; Rutkevich, I.

1981-01-01

A theory is derived for the motion of fast ionization waves along a plane slab of a weakly ionized plasma. The properties of the ionization wave are shown to be closely related to the motion of a two-dimensional surface-charge wave along the slab boundaries. As a result, the ionization wave is quite different from a one-dimensional wave. A quasi-one-dimensional description is used for the wave motion, in which the initial equations are averaged over the transverse coordinate. The relationship between the normal component of the current density at the plasma boundary and the amplitude of the electric potential from the linear theory for a surface wave is used to close the system of averaged equations. Self-similar solutions are derived for these equations; the solutions describe space-charge solitons and electric-field solitons which ionize the plasma. The theory is used to explain the motion of fast ionization waves in long discharge tubes

Correlated motion of protein subdomains and large-scale conformational flexibility of RecA protein filament

Science.gov (United States)

Yu, Garmay; A, Shvetsov; D, Karelov; D, Lebedev; A, Radulescu; M, Petukhov; V, Isaev-Ivanov

2012-02-01

Based on X-ray crystallographic data available at Protein Data Bank, we have built molecular dynamics (MD) models of homologous recombinases RecA from E. coli and D. radiodurans. Functional form of RecA enzyme, which is known to be a long helical filament, was approximated by a trimer, simulated in periodic water box. The MD trajectories were analyzed in terms of large-scale conformational motions that could be detectable by neutron and X-ray scattering techniques. The analysis revealed that large-scale RecA monomer dynamics can be described in terms of relative motions of 7 subdomains. Motion of C-terminal domain was the major contributor to the overall dynamics of protein. Principal component analysis (PCA) of the MD trajectories in the atom coordinate space showed that rotation of C-domain is correlated with the conformational changes in the central domain and N-terminal domain, that forms the monomer-monomer interface. Thus, even though C-terminal domain is relatively far from the interface, its orientation is correlated with large-scale filament conformation. PCA of the trajectories in the main chain dihedral angle coordinate space implicates a co-existence of a several different large-scale conformations of the modeled trimer. In order to clarify the relationship of independent domain orientation with large-scale filament conformation, we have performed analysis of independent domain motion and its implications on the filament geometry.

Long-term passive distance-bounded relative motion in the presence of TeX perturbations

NARCIS (Netherlands)

Chu, J.; Guo, J.; Gill, E.K.A.

2015-01-01

This paper presents closed-form solutions for the problem of long-term satellite relative motion in the presence of J2 perturbations, and introduces a design methodology for long-term passive distance-bounded relative motion. There are two key ingredients of closed-form solutions.One is the model of

Relation of external surface to internal tumor motion studied with cine CT

International Nuclear Information System (INIS)

Chi, P.-C.M.; Balter, Peter; Luo Dershan; Mohan, Radhe; Pan Tinsu

2006-01-01

The accuracy of delivering gated-radiation therapy to lung tumors using an external respiratory surrogate relies on not only interfractional and intrafractional reproducibility, but also a strong correlation between external motion and internal tumor motion. The purpose of this work was to use the cine images acquired by four-dimensional computed tomography acquisition protocol to study the relation between external surface motion and internal tumor motion. The respiratory phase information of tumor motion and chest wall motion was measured on the cine images using a proposed region-of-interest (ROI) method and compared to measurement of an external respiratory monitoring device. On eight lung patient data sets, the phase shifts were measured between (1) the signal of a real-time positioning-management (RPM) respiratory monitoring device placed in the abdominal region and four surface locations on the chest wall (2) the RPM signal in the abdominal region and tumor motions, and (3) chest wall surface motions and tumor motions. Respiratory waveforms measured at different surface locations during the same respiratory cycle often varied and had significant phase shifts. Seven of the 8 patients showed the abdominal motion leading chest wall motion. The best correlation (smallest phase shift) was found between the abdominal motion and the superior-inferior (S-I) tumor motion. A wide range of phase shifts was observed between external surface motion and tumor anterior-posterior (A-P)/lateral motion. The result supported the placement of the RPM block in the abdominal region and suggested that during a gated therapy utilizing the RPM system, it is necessary to place the RPM block at the same location as it is during treatment simulation in order to reduce potential errors introduced by the position of the RPM block. Correlations between external motions and lateral/A-P tumor motions were inconclusive due to a combination of patient selection and the limitation of the ROI

PRECISION MOTION SYSTEM FOR OPTO-MECHANICAL EQUIPMENT OF MICROELECTRONICS

Directory of Open Access Journals (Sweden)

I. V. Dainiak

2015-01-01

Full Text Available The paper proposes a structure of precision motion system built on the basis of a circular multi-coordinate synchronous segment motor and reconfigurable parallel kinematic mechanism. The multi-coordinate synchronous segment motor may have from two to six movable segments depending on the design, and number of the segments generally defines an internal mobility of the motor. A specific feature of the parallel kinematic mechanism consists in the possibility of its structure reconfiguration by serial connection of two neighboring rods with the help of free elements of their spherical joints into triangular circuits with one spherical hinge at the common vertex. As result of this, the controlled motion of motor movable segments is transformed into the complex spatial displacement of circular platform with number of degrees of freedom up to six inclusively.A mathematical model for solution of the kinematic problem in the investigated parallel mechanism has been offered in the paper. The model allows to calculate a position of movable segments of multi-coordinate synchronous motor depending on the desired position and orientation of the executive circular platform. The parametric definition of base point positions in the motor segments in time allows eventually to form algorithms of programmable motions.The paper substantiates ability to embed the developed motion system into projection unit of opto-mechanical equipment while preserving traditional configuration scheme. This provides the possibility of adaptive adjustment of optical elements during operation; it allows to adjust the optical elements when the geometry of projection system is changed due to deterioration. As result, main characteristics of projection system: resolution, depth of field and image contrast and distortion are maintained at the required level. The developed motion system can be used as a coordinate system of positioning, alignment and scanning in the assembly and other

The linear parameters and the decoupling matrix for linearly coupled motion in 6 dimensional phase space

International Nuclear Information System (INIS)

Parzen, G.

1997-01-01

It will be shown that starting from a coordinate system where the 6 phase space coordinates are linearly coupled, one can go to a new coordinate system, where the motion is uncoupled, by means of a linear transformation. The original coupled coordinates and the new uncoupled coordinates are related by a 6 x 6 matrix, R. It will be shown that of the 36 elements of the 6 x 6 decoupling matrix R, only 12 elements are independent. A set of equations is given from which the 12 elements of R can be computed form the one period transfer matrix. This set of equations also allows the linear parameters, the β i , α i , i = 1, 3, for the uncoupled coordinates, to be computed from the one period transfer matrix

SM-ROM-GL (Strong Motion Romania Ground Level Database

Directory of Open Access Journals (Sweden)

Ioan Sorin BORCIA

2015-07-01

Full Text Available The SM-ROM-GL database includes data obtained by the processing of records performed at ground level by the Romanian seismic networks, namely INCERC, NIEP, NCSRR and ISPH-GEOTEC, during recent seismic events with moment magnitude Mw ≥ 5 and epicenters located in Romania. All the available seismic records were re-processed using the same basic software and the same procedures and options (filtering and baseline correction, in order to obtain a consistent dataset. The database stores computed parameters of seismic motions, i.e. peak values: PGA, PGV, PGD, effective peak values: EPA, EPV, EPD, control periods, spectral values of absolute acceleration, relative velocity and relative displacement, as well as of instrumental intensity (as defined bz Sandi and Borcia in 2011. The fields in the database include: coding of seismic events, stations and records, a number of associated fields (seismic event source parameters, geographical coordinates of seismic stations, links to the corresponding ground motion records, charts of the response spectra of absolute acceleration, relative velocity, relative displacement and instrumental intensity, as well as some other representative parameters of seismic motions. The conception of the SM-ROM-GL database allows for an easy maintenance; such that elementary knowledge of Microsoft Access 2000 is sufficient for its operation.

Visual event-related potentials to biological motion stimuli in autism spectrum disorders

Science.gov (United States)

Bletsch, Anke; Krick, Christoph; Siniatchkin, Michael; Jarczok, Tomasz A.; Freitag, Christine M.; Bender, Stephan

2014-01-01

Atypical visual processing of biological motion contributes to social impairments in autism spectrum disorders (ASD). However, the exact temporal sequence of deficits of cortical biological motion processing in ASD has not been studied to date. We used 64-channel electroencephalography to study event-related potentials associated with human motion perception in 17 children and adolescents with ASD and 21 typical controls. A spatio-temporal source analysis was performed to assess the brain structures involved in these processes. We expected altered activity already during early stimulus processing and reduced activity during subsequent biological motion specific processes in ASD. In response to both, random and biological motion, the P100 amplitude was decreased suggesting unspecific deficits in visual processing, and the occipito-temporal N200 showed atypical lateralization in ASD suggesting altered hemispheric specialization. A slow positive deflection after 400 ms, reflecting top-down processes, and human motion-specific dipole activation differed slightly between groups, with reduced and more diffuse activation in the ASD-group. The latter could be an indicator of a disrupted neuronal network for biological motion processing in ADS. Furthermore, early visual processing (P100) seems to be correlated to biological motion-specific activation. This emphasizes the relevance of early sensory processing for higher order processing deficits in ASD. PMID:23887808

Response of Voronezh reactor type to horizontal ground motion

International Nuclear Information System (INIS)

Pecinka, L.

1983-01-01

For the purposes of vibration monitoring of PWR's the well known 'double pendulum model' has been developed and experimentally verified. It is shown, that this model is possible to use for response calculations of Voronezh reactor pressure vessel and its internals to horizontal ground motion. The equation of motion is given in usual matrix form, the damping matrix is calculated by Rayleigh formula. Driving force is given by vector of ground motion in horizontal direction. For the numerical integration of equation of motion is possible to use following methods - matrix exponential in state space; - modal analysis; - one-step direct integration. For our purposes the last one has been chosen and related computer code TRANS has been developed. The results of calculations are given in the graphically form using generalized angular coordinates and its second derivatives, which describes the displacement or acceleration of reactor pressure vessel to ground and the core barrel to reactor pressure vessel. The driving vector is given in the form of artificially generated accelerogram. (orig./HP)

Iterative solution of the Grad-Shafranov equation in symmetric magnetic coordinates

International Nuclear Information System (INIS)

Brambilla, Marco

2003-01-01

The inverse Grad-Shafranov equation for axisymmetric magnetohydrodynamic equilibria is reformulated in symmetric magnetic coordinates (in which magnetic field lines look 'straight', and the geometric toroidal angle is one of the coordinates). The poloidally averaged part of the equilibrium condition and Ampere law takes the form of two first-order ordinary differential equations, with the two arbitrary flux functions, pressure and force-free part of the current density, as sources. The condition for the coordinates to be flux coordinates, and the poloidally varying part of the equilibrium equation are similarly transformed into a set of first-order ordinary differential equations, with coefficients depending on the metric, and explicitly solved for the radial derivatives of the coefficients of the Fourier representation of the Cartesian coordinates in the poloidal angle. The derivation exploits the existence of Boozer-White coordinates, but does not require to find these coordinates explicitly; on the other hand, it offers a simple recipe to perform the transformation to Boozer-White coordinates, if required. Use of symmetric flux coordinates is advantageous for the formulation of many problems of equilibrium, stability, and wave propagation in tokamak plasmas, since these coordinates have the simplest metric of their class. It is also shown that in symmetric flux coordinates the Lagrangian equations of the drift motion of charged particles are automatically solved for the time derivatives, with right-hand sides closely related to the coefficients of the inverse Grad-Shafranov equation

A Direct Method for Mapping the Center of Pressure Measured by an Insole Pressure Sensor System to the Shoe's Local Coordinate System.

Science.gov (United States)

Weaver, Brian T; Braman, Jerrod E; Haut, Roger C

2016-06-01

A direct method to express the center of pressure (CoP) measured by an insole pressure sensor system (IPSS) into a known coordinate system measured by motion tracking equipment is presented. A custom probe was constructed with reflective markers to allow its tip to be precisely tracked with motion tracking equipment. This probe was utilized to activate individual sensors on an IPSS that was placed in a shoe fitted with reflective markers used to establish a local shoe coordinate system. When pressed onto the IPSS the location of the probe's tip was coincident with the CoP measured by the IPSS (IPSS-CoP). Two separate pushes (i.e., data points) were used to develop vectors in each respective coordinate system. Simple vector mathematics determined the rotational and translational components of the transformation matrix needed to express the IPSS-CoP into the local shoe coordinate system. Validation was performed by comparing IPSS-CoP with an embedded force plate measured CoP (FP-CoP) from data gathered during kinematic trials. Six male subjects stood on an embedded FP and performed anterior/posterior (AP) sway, internal rotation, and external rotation of the body relative to a firmly planted foot. The IPSS-CoP was highly correlated with the FP-CoP for all motions, root mean square errors (RMSRRs) were comparable to other research, and there were no statistical differences between the displacement of the IPSS-CoP and FP-CoP for both the AP and medial/lateral (ML) axes, respectively. The results demonstrated that this methodology could be utilized to determine the transformation variables need to express IPSS-CoP into a known coordinate system measured by motion tracking equipment and that these variables can be determined outside the laboratory anywhere motion tracking equipment is available.

Pulsar timing and general relativity

Science.gov (United States)

Backer, D. C.; Hellings, R. W.

1986-01-01

Techniques are described for accounting for relativistic effects in the analysis of pulsar signals. Design features of instrumentation used to achieve millisecond accuracy in the signal measurements are discussed. The accuracy of the data permits modeling the pulsar physical characteristics from the natural glitches in the emissions. Relativistic corrections are defined for adjusting for differences between the pulsar motion in its spacetime coordinate system relative to the terrestrial coordinate system, the earth's motion, and the gravitational potentials of solar system bodies. Modifications of the model to allow for a binary pulsar system are outlined, including treatment of the system as a point mass. Finally, a quadrupole model is presented for gravitational radiation and techniques are defined for using pulsars in the search for gravitational waves.

2001 Bhuj, India, earthquake engineering seismoscope recordings and Eastern North America ground-motion attenuation relations

Science.gov (United States)

Cramer, C.H.; Kumar, A.

2003-01-01

Engineering seismoscope data collected at distances less than 300 km for the M 7.7 Bhuj, India, mainshock are compatible with ground-motion attenuation in eastern North America (ENA). The mainshock ground-motion data have been corrected to a common geological site condition using the factors of Joyner and Boore (2000) and a classification scheme of Quaternary or Tertiary sediments or rock. We then compare these data to ENA ground-motion attenuation relations. Despite uncertainties in recording method, geological site corrections, common tectonic setting, and the amount of regional seismic attenuation, the corrected Bhuj dataset agrees with the collective predictions by ENA ground-motion attenuation relations within a factor of 2. This level of agreement is within the dataset uncertainties and the normal variance for recorded earthquake ground motions.

4D ANIMATION RECONSTRUCTION FROM MULTI-CAMERA COORDINATES TRANSFORMATION

Directory of Open Access Journals (Sweden)

J. P. Jhan

2016-06-01

Full Text Available Reservoir dredging issues are important to extend the life of reservoir. The most effective and cost reduction way is to construct a tunnel to desilt the bottom sediment. Conventional technique is to construct a cofferdam to separate the water, construct the intake of tunnel inside and remove the cofferdam afterwards. In Taiwan, the ZengWen reservoir dredging project will install an Elephant-trunk Steel Pipe (ETSP in the water to connect the desilting tunnel without building the cofferdam. Since the installation is critical to the whole project, a 1:20 model was built to simulate the installation steps in a towing tank, i.e. launching, dragging, water injection, and sinking. To increase the construction safety, photogrammetry technic is adopted to record images during the simulation, compute its transformation parameters for dynamic analysis and reconstruct the 4D animations. In this study, several Australis© coded targets are fixed on the surface of ETSP for auto-recognition and measurement. The cameras orientations are computed by space resection where the 3D coordinates of coded targets are measured. Two approaches for motion parameters computation are proposed, i.e. performing 3D conformal transformation from the coordinates of cameras and relative orientation computation by the orientation of single camera. Experimental results show the 3D conformal transformation can achieve sub-mm simulation results, and relative orientation computation shows the flexibility for dynamic motion analysis which is easier and more efficiency.

Integrals of the motion, Green functions, and coherent states of dynamical systems

International Nuclear Information System (INIS)

Dodonov, V.V.; Malkin, I.A.; Man'ko, V.I.

1975-01-01

The connection between the integrals of the motion of a quantum system and its Green function is established. The Green function is shown to be the eigenfunction of the integrals of the motion which describe initial points of the system trajectory in the phase space of average coordinates and moments. The explicit expressions for the Green functions of the N-dimensional system with the Hamiltonians which is the most general quadratic form of coordinates and momenta with time-dependent coefficients is obtained in coordinate, momentum, and coherent states representations. The Green functions of the nonstationary singular oscillator and of the stationary Schroedinger equation are also obtained. (author)

A bipedal DNA Brownian motor with coordinated legs.

Science.gov (United States)

Omabegho, Tosan; Sha, Ruojie; Seeman, Nadrian C

2009-04-03

A substantial challenge in engineering molecular motors is designing mechanisms to coordinate the motion between multiple domains of the motor so as to bias random thermal motion. For bipedal motors, this challenge takes the form of coordinating the movement of the biped's legs so that they can move in a synchronized fashion. To address this problem, we have constructed an autonomous DNA bipedal walker that coordinates the action of its two legs by cyclically catalyzing the hybridization of metastable DNA fuel strands. This process leads to a chemically ratcheted walk along a directionally polar DNA track. By covalently cross-linking aliquots of the walker to its track in successive walking states, we demonstrate that this Brownian motor can complete a full walking cycle on a track whose length could be extended for longer walks. We believe that this study helps to uncover principles behind the design of unidirectional devices that can function without intervention. This device should be able to fulfill roles that entail the performance of useful mechanical work on the nanometer scale.

Convex optimisation approach to constrained fuel optimal control of spacecraft in close relative motion

Science.gov (United States)

Massioni, Paolo; Massari, Mauro

2018-05-01

This paper describes an interesting and powerful approach to the constrained fuel-optimal control of spacecraft in close relative motion. The proposed approach is well suited for problems under linear dynamic equations, therefore perfectly fitting to the case of spacecraft flying in close relative motion. If the solution of the optimisation is approximated as a polynomial with respect to the time variable, then the problem can be approached with a technique developed in the control engineering community, known as "Sum Of Squares" (SOS), and the constraints can be reduced to bounds on the polynomials. Such a technique allows rewriting polynomial bounding problems in the form of convex optimisation problems, at the cost of a certain amount of conservatism. The principles of the techniques are explained and some application related to spacecraft flying in close relative motion are shown.

The syntax of appositive relativization : On specifying coordination, false free relatives, and promotion

NARCIS (Netherlands)

de Vries, Mark

2006-01-01

Appositive relative clauses differ in some essential respects from restrictive relative clauses. I argue that appositive relatives and appositions can be put together as a third class of coordination denoting specification. Thus, an appositive relative is a specifying conjunct to the visible

Case management for high-intensity service users: towards a relational approach to care co-ordination.

Science.gov (United States)

McEvoy, Phil; Escott, Diane; Bee, Penny

2011-01-01

This study is based on a formative evaluation of a case management service for high-intensity service users in Northern England. The evaluation had three main purposes: (i) to assess the quality of the organisational infrastructure; (ii) to obtain a better understanding of the key influences that played a role in shaping the development of the service; and (iii) to identify potential changes in practice that may help to improve the quality of service provision. The evaluation was informed by Gittell's relational co-ordination theory, which focuses upon cross-boundary working practices that facilitate task integration. The Assessment of Chronic Illness Care Survey was used to assess the organisational infrastructure and qualitative interviews with front line staff were conducted to explore the key influences that shaped the development of the service. A high level of strategic commitment and political support for integrated working was identified. However, the quality of care co-ordination was variable. The most prominent operational factor that appeared to influence the scope and quality of care co-ordination was the pattern of interaction between the case managers and their co-workers. The co-ordination of patient care was much more effective in integrated co-ordination networks. Key features included clearly defined, task focussed, relational workspaces with interactive forums where case managers could engage with co-workers in discussions about the management of interdependent care activities. In dispersed co-ordination networks with fewer relational workspaces, the case managers struggled to work as effectively. The evaluation concluded that the creation of flexible and efficient task focused relational workspaces that are systemically managed and adequately resourced could help to improve the quality of care co-ordination, particularly in dispersed networks. © 2010 Blackwell Publishing Ltd.

The Southern Double Stars of Carl Rümker II: Their Relative Rectilinear Motion

Science.gov (United States)

Letchford, Roderick; White, Graeme; Ernest, Allan

2018-04-01

A description of the relative rectilinear motion of double stars provides an important clue to the relationship of the components. The aim is to provide an objective method of obtaining Rectilinear Elements. We present a simplified method to calculate relative rectilinear motion, relying on the data obtained from the HIPPARCOS and GAIA DR1 missions, together with their uncertainties. As examples, we present the Rectilinear Elements of RMK 1, 3, 4, 5, 6, 8, 10, 11, 12, 17, 20, 25, 27, and 28.

High-accuracy optical extensometer based on coordinate transform in two-dimensional digital image correlation

Science.gov (United States)

Lv, Zeqian; Xu, Xiaohai; Yan, Tianhao; Cai, Yulong; Su, Yong; Zhang, Qingchuan

2018-01-01

In the measurement of plate specimens, traditional two-dimensional (2D) digital image correlation (DIC) is challenged by two aspects: (1) the slant optical axis (misalignment of the optical camera axis and the object surface) and (2) out-of-plane motions (including translations and rotations) of the specimens. There are measurement errors in the results measured by 2D DIC, especially when the out-of-plane motions are big enough. To solve this problem, a novel compensation method has been proposed to correct the unsatisfactory results. The proposed compensation method consists of three main parts: 1) a pre-calibration step is used to determine the intrinsic parameters and lens distortions; 2) a compensation panel (a rigid panel with several markers located at known positions) is mounted to the specimen to track the specimen's motion so that the relative coordinate transformation between the compensation panel and the 2D DIC setup can be calculated using the coordinate transform algorithm; 3) three-dimensional world coordinates of measuring points on the specimen can be reconstructed via the coordinate transform algorithm and used to calculate deformations. Simulations have been carried out to validate the proposed compensation method. Results come out that when the extensometer length is 400 pixels, the strain accuracy reaches 10 με no matter out-of-plane translations (less than 1/200 of the object distance) nor out-of-plane rotations (rotation angle less than 5°) occur. The proposed compensation method leads to good results even when the out-of-plane translation reaches several percents of the object distance or the out-of-plane rotation angle reaches tens of degrees. The proposed compensation method has been applied in tensile experiments to obtain high-accuracy results as well.

Motion of the MMS Spacecraft Relative to the Magnetic Reconnection Structure Observed on 16 October 2015 at 1307 UT

Science.gov (United States)

Denton, R. E.; Sonnerup, B. U. O.; Hasegawa, H.; Phan, T. D.; Russell, C. T.; Strangeway, R.; Giles, B. L.; Gershman, D.; Torbert, R. B.

2016-01-01

We analyze a magnetopause crossing by the Magnetospheric Multiscale (MMS) spacecraft at 1307 UT on 16 October 2016 that showed features of electron-scale reconnection. For this event, we find orthonormal LMN coordinates from the magnetic field, with N and L varying respectively along the maximum gradient and maximum variance directions. We find the motion along N from the Spatio-Temporal Difference analysis and motion along L from measured particle velocities. We locate the position of the magnetic X point, finding that MMS-4 passed within about 1A km from the X point and that MMS-3 and MMS-2 passed within about 1.7 km and 2.4 km, respectively, from the position of maximum out of plane current.

Psychomotor skills assessment by motion analysis in minimally invasive surgery on an animal organ.

Science.gov (United States)

Hofstad, Erlend Fagertun; Våpenstad, Cecilie; Bø, Lars Eirik; Langø, Thomas; Kuhry, Esther; Mårvik, Ronald

2017-08-01

A high level of psychomotor skills is required to perform minimally invasive surgery (MIS) safely. To be able to measure these skills is important in the assessment of surgeons, as it enables constructive feedback during training. The aim of this study was to test the validity of an objective and automatic assessment method using motion analysis during a laparoscopic procedure on an animal organ. Experienced surgeons in laparoscopy (experts) and medical students (novices) performed a cholecystectomy on a porcine liver box model. The motions of the surgical tools were acquired and analyzed by 11 different motion-related metrics, i.e., a total of 19 metrics as eight of them were measured separately for each hand. We identified for which of the metrics the experts outperformed the novices. In total, two experts and 28 novices were included. The experts achieved significantly better results for 13 of the 19 instrument motion metrics. Expert performance is characterized by a low time to complete the cholecystectomy, high bimanual dexterity (instrument coordination), a limited amount of movement and low measurement of motion smoothness of the dissection instrument, and relatively high usage of the grasper to optimize tissue positioning for dissection.

Biomechanical model-based displacement estimation in micro-sensor motion capture

International Nuclear Information System (INIS)

Meng, X L; Sun, S Y; Wu, J K; Zhang, Z Q; 3 Building, 21 Heng Mui Keng Terrace (Singapore))" data-affiliation=" (Department of Electrical and Computer Engineering, National University of Singapore (NUS), 02-02-10 I3 Building, 21 Heng Mui Keng Terrace (Singapore))" >Wong, W C

2012-01-01

In micro-sensor motion capture systems, the estimation of the body displacement in the global coordinate system remains a challenge due to lack of external references. This paper proposes a self-contained displacement estimation method based on a human biomechanical model to track the position of walking subjects in the global coordinate system without any additional supporting infrastructures. The proposed approach makes use of the biomechanics of the lower body segments and the assumption that during walking there is always at least one foot in contact with the ground. The ground contact joint is detected based on walking gait characteristics and used as the external references of the human body. The relative positions of the other joints are obtained from hierarchical transformations based on the biomechanical model. Anatomical constraints are proposed to apply to some specific joints of the lower body to further improve the accuracy of the algorithm. Performance of the proposed algorithm is compared with an optical motion capture system. The method is also demonstrated in outdoor and indoor long distance walking scenarios. The experimental results demonstrate clearly that the biomechanical model improves the displacement accuracy within the proposed framework. (paper)

Hierarchical Motion Control for a Team of Humanoid Soccer Robots

Directory of Open Access Journals (Sweden)

Seung-Joon Yi

2016-02-01

Full Text Available Robot soccer has become an effective benchmarking problem for robotics research as it requires many aspects of robotics including perception, self localization, motion planning and distributed coordination to work in uncertain and adversarial environments. Especially with humanoid robots that lack inherent stability, a capable and robust motion controller is crucial for generating walking and kicking motions without losing balance. In this paper, we describe the details of a motion controller to control a team of humanoid soccer robots, which consists of a hierarchy of controllers with different time frames and abstraction levels. A low level controller governs the real time control of each joint angle, either using target joint angles or target endpoint transforms. A mid-level controller handles bipedal locomotion and balancing of the robot. A high level controller decides the long term behavior of the robot, and finally the team level controller coordinates the behavior of a group of robots by means of asynchronous communication between the robots. The suggested motion system has been successfully used by many humanoid robot teams at the RoboCup international robot soccer competitions, which has awarded us five successful championships in a row.

Analytical solution of perturbed relative motion: an application of satellite formations to geodesy

Science.gov (United States)

Wnuk, Edwin

In the upcoming years, several space missions will be operated using a number of spacecraft flying in formation. Clusters of spacecraft with a carefully designed orbits and optimal formation geometry enable a wide variety of applications ranging from remote sensing to astronomy, geodesy and basic physics. Many of the applications require precise relative navigation and autonomous orbit control of satellites moving in a formation. For many missions a centimeter level of orbit control accuracy is required. The GRACE mission, since its launch in 2002, has been improving the Earth's gravity field model to a very high level of accuracy. This mission is a formation flying one consisting of two satellites moving in coplanar orbits and provides range and range-rate measurements between the satellites in the along-track direction. Future geodetic missions probably will employ alternative architectures using additional satellites and/or performing out-of-plane motion, e.g cartwheel orbits. The paper presents an analytical model of a satellite formation motion that enables propagation of the relative spacecraft motion. The model is based on the analytical theory of satellite relative motion that was presented in the previous our papers (Wnuk and Golebiewska, 2005, 2006). This theory takes into account the influence of the following gravitational perturbation effects: 1) zonal and tesseral harmonic geopotential coefficients up to arbitrary degree and order, 2) Lunar gravity, 3) Sun gravity. Formulas for differential perturbations were derived with any restriction concerning a plane of satellite orbits. They can be applied in both: in plane and out of plane cases. Using this propagator we calculated relative orbits and future relative satellite positions for different types of formations: in plane, out of plane, cartwheel and others. We analyzed the influence of particular parts of perturbation effects and estimated the accuracy of predicted relative spacecrafts positions

Ground Motion Relations for the Upper Rhine Graben

Science.gov (United States)

Calbini, V.; Granet, M.; Camelbeeck, T.

2006-12-01

Earthquake in Europe are primarily located within the Euro-Mediterranean domain. However, the Upper Rhine Graben (URG) region regularly suffers earthquakes which are felt physically by inhabitants and cause damage to private property and the industrial infrastructure. In 1356, a major earthquake (I0 = X) destroyed part of the city of Basel. Recently, several events having M > 5 have shaken this area. In the framework of an INTERREG III project funded by the European community, a microzonation study has been achieved across the "three borders" area including the cities of Basel and Mulhouse. In particular, the ground motion was studied. The URG, which belongs to the ECRIS (European Cenozoic Rift System), is characterized by rift-related sedimentary basins with several hundreds meters of tertiary sediments overlaying the basement. Such a subsurface geology leads to strong site effects. Predictive attenuation laws and their related uncertainties are evaluated considering strong motions records and velocimetric records from small to moderate local events (Magnitude ranging 3 related to a frequency dependant quality factor). Site effects are considered by using transfer functions calculated for each station. Finally, the relationships between Ml and Mw are investigated. The results show a dependence of these laws on the frequency band and a discrepancy with general laws obtained for western and central Europe. We shall discuss these results in the tectonic and geologic context of URG.

Relative-coordinate determination for visual double stars by applying Fourier transforms

Directory of Open Access Journals (Sweden)

Radović Viktor

2013-01-01

Full Text Available We discuss the software developed for the purpose of determining the relative coordinates (position angle θ and separation ρ for visual double or multiple stars. It is based on application of Fourier transforms in treating CCD frames of these systems. The objective was to determine the relative coordinates automatically to an extent as large as possible. In this way the time needed for the reduction of many CCD frames becomes shorter. The capabilities and limitations of the software are examined. Besides, the possibility of improving is also considered. The software has been tested and checked on a sample consisting of CCD frames of 165 double or multiple stars obtained with the 2m telescope at NAO Rozhen in Bulgaria in October 2011. The results have been compared with the corresponding results obtained by applying different software and the agreement is found to be very good.

Movement coordination patterns between the foot joints during walking

Directory of Open Access Journals (Sweden)

John B. Arnold

2017-10-01

Full Text Available Abstract Background In 3D gait analysis, kinematics of the foot joints are usually reported via isolated time histories of joint rotations and no information is provided on the relationship between rotations at different joints. The aim of this study was to identify movement coordination patterns in the foot during walking by expanding an existing vector coding technique according to an established multi-segment foot and ankle model. A graphical representation is also described to summarise the coordination patterns of joint rotations across multiple patients. Methods Three-dimensional multi-segment foot kinematics were recorded in 13 adults during walking. A modified vector coding technique was used to identify coordination patterns between foot joints involving calcaneus, midfoot, metatarsus and hallux segments. According to the type and direction of joints rotations, these were classified as in-phase (same direction, anti-phase (opposite directions, proximal or distal joint dominant. Results In early stance, 51 to 75% of walking trials showed proximal-phase coordination between foot joints comprising the calcaneus, midfoot and metatarsus. In-phase coordination was more prominent in late stance, reflecting synergy in the simultaneous inversion occurring at multiple foot joints. Conversely, a distal-phase coordination pattern was identified for sagittal plane motion of the ankle relative to the midtarsal joint, highlighting the critical role of arch shortening to locomotor function in push-off. Conclusions This study has identified coordination patterns between movement of the calcaneus, midfoot, metatarsus and hallux by expanding an existing vector cording technique for assessing and classifying coordination patterns of foot joints rotations during walking. This approach provides a different perspective in the analysis of multi-segment foot kinematics, and may be used for the objective quantification of the alterations in foot joint

The covariance of GPS coordinates and frames

International Nuclear Information System (INIS)

Lachieze-Rey, Marc

2006-01-01

We explore, in the general relativistic context, the properties of the recently introduced global positioning system (GPS) coordinates, as well as those of the associated frames and coframes that they define. We show that they are covariant and completely independent of any observer. We show that standard spectroscopic and astrometric observations allow any observer to measure (i) the values of the GPS coordinates at his position (ii) the components of his 4-velocity and (iii) the components of the metric in the GPS frame. This provides this system with a unique value both for conceptual discussion (no frame dependence) and for practical use (involved quantities are directly measurable): localization, motion monitoring, astrometry, cosmography and tests of gravitation theories. We show explicitly, in the general relativistic context, how an observer may estimate his position and motion, and reconstruct the components of the metric. This arises from two main results: the extension of the velocity fields of the probes to the whole (curved) spacetime, and the identification of the components of the observer's velocity in the GPS frame with the (inversed) observed redshifts of the probes. Specific cases (non-relativistic velocities, Minkowski and Friedmann-Lemaitre spacetimes, geodesic motions) are studied in detail

On the relation of earthquake stress drop and ground motion variability

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Oth, Adrien; Miyake, Hiroe; Bindi, Dino

2017-07-01

One of the key parameters for earthquake source physics is stress drop since it can be directly linked to the spectral level of ground motion. Stress drop estimates from moment corner frequency analysis have been shown to be extremely variable, and this to a much larger degree than expected from the between-event ground motion variability. This discrepancy raises the question whether classically determined stress drop variability is too large, which would have significant consequences for seismic hazard analysis. We use a large high-quality data set from Japan with well-studied stress drop data to address this issue. Nonparametric and parametric reference ground motion models are derived, and the relation of between-event residuals for Japan Meteorological Agency equivalent seismic intensity and peak ground acceleration with stress drop is analyzed for crustal earthquakes. We find a clear correlation of the between-event residuals with stress drops estimates; however, while the island of Kyushu is characterized by substantially larger stress drops than Honshu, the between-event residuals do not reflect this observation, leading to the appearance of two event families with different stress drop levels yet similar range of between-event residuals. Both the within-family and between-family stress drop variations are larger than expected from the ground motion between-event variability. A systematic common analysis of these parameters holds the potential to provide important constraints on the relative robustness of different groups of data in the different parameter spaces and to improve our understanding on how much of the observed source parameter variability is likely to be true source physics variability.

Interactive motion tracing for Rowing Training

DEFF Research Database (Denmark)

Dai, Zheng

2011-01-01

This paper studies motion tracking and team coordination for the training of rowers. The design research is drawn upon the division of contribution between the designers input and the user input in a design process. We built a training system that can record and show the action of a rower’s hand....... Designer proposed solutions for both a fundamental problem and a very advanced problem. Users guided the design direction, and spoke what they expected or what they disliked. As the result, our design provided a real-time recording tool for rowers and coaches to discuss and analyze the motion. The coach...... can correct the path immediately and save the corrected path for the rower to try to imitate and train. The members in a rowing team train with the same path from to coordinate and synchronize their actions for the best performance. The training system was developed through a user-centered design...

A comparison between the adiabatic time dependent Hartree-Fock and the generator coordinate methods for the description of nuclear collective motion

International Nuclear Information System (INIS)

Villars, F.

1975-01-01

The objective of the work is to draw attention to the essential equivalence of the two apparently quite distinct ways of describing nuclear collective dyanmics, the adiabatic time-dependent Hartree-Fock method (ADTHF) on the one hand, and the Generator Coordinate (GC) method on the other hand. To demonstrate this relation, an analysis of the simplest case, in which collective motion is described by a single collective para- meter q(t) is presented. In the ATDHF approach, two self-consistency conditions are obtained; the resultant expressions for the collective potential and kinetic energies represent a special case of the more general results of Baranger and Veneroni. In the G.C. approach to the same system (with the same collective parameter q), the narrow overlap approximation must be made, as the counterpart of the adiabatic approximation in the TDHF method. In its conventional form, the G.C. method leads to a different expression for the collective kinetic energy. It is shown however, that a simple generalization of the G.C.-wave function leads to corrections determined by a variational principle. In leading order, the corrected expression for the collective kinetic energy is identical with the TDHF result In both cases, the collective inertia is determined by a self-consistent cranking formula

SU-E-P-41: Imaging Coordination of Cone Beam CT, On-Board Image Conjunction with Optical Image Guidance for SBRT Treatment with Respiratory Motion Management

International Nuclear Information System (INIS)

Liu, Y; Campbell, J

2015-01-01

Purpose: To spare normal tissue for SBRT lung/liver patients, especially for patients with significant tumor motion, image guided respiratory motion management has been widely implemented in clinical practice. The purpose of this study was to evaluate imaging coordination of cone beam CT, on-board X-ray image conjunction with optical image guidance for SBRT treatment with motion management. Methods: Currently in our clinic a Varian Novlis Tx was utilized for treating SBRT patients implementing CBCT. A BrainLAB X-ray ExacTrac imaging system in conjunction with optical guidance was primarily used for SRS patients. CBCT and X-ray imaging system were independently calibrated with 1.0 mm tolerance. For SBRT lung/liver patients, the magnitude of tumor motion was measured based-on 4DCT and the measurement was analyzed to determine if patients would be beneficial with respiratory motion management. For patients eligible for motion management, an additional CT with breath holding would be scanned and used as primary planning CT and as reference images for Cone beam CT. During the SBRT treatment, a CBCT with pause and continuing technology would be performed with patients holding breath, which may require 3–4 partially scanned CBCT to combine as a whole CBCT depending on how long patients capable of holding breath. After patients being setup by CBCT images, the ExactTrac X-ray imaging system was implemented with patients’ on-board X-ray images compared to breath holding CT-based DRR. Results: For breath holding patients SBRT treatment, after initially localizing patients with CBCT, we then position patients with ExacTrac X-ray and optical imaging system. The observed deviations of real-time optical guided position average at 3.0, 2.5 and 1.5 mm in longitudinal, vertical and lateral respectively based on 35 treatments. Conclusion: The respiratory motion management clinical practice improved our physician confidence level to give tighter tumor margin for sparing normal

Predicted Attenuation Relation and Observed Ground Motion of Gorkha Nepal Earthquake of 25 April 2015

Science.gov (United States)

Singh, R. P.; Ahmad, R.

2015-12-01

A comparison of recent observed ground motion parameters of recent Gorkha Nepal earthquake of 25 April 2015 (Mw 7.8) with the predicted ground motion parameters using exitsing attenuation relation of the Himalayan region will be presented. The recent earthquake took about 8000 lives and destroyed thousands of poor quality of buildings and the earthquake was felt by millions of people living in Nepal, China, India, Bangladesh, and Bhutan. The knowledge of ground parameters are very important in developing seismic code of seismic prone regions like Himalaya for better design of buildings. The ground parameters recorded in recent earthquake event and aftershocks are compared with attenuation relations for the Himalayan region, the predicted ground motion parameters show good correlation with the observed ground parameters. The results will be of great use to Civil engineers in updating existing building codes in the Himlayan and surrounding regions and also for the evaluation of seismic hazards. The results clearly show that the attenuation relation developed for the Himalayan region should be only used, other attenuation relations based on other regions fail to provide good estimate of observed ground motion parameters.

Collective motion in quantum many-body systems

Energy Technology Data Exchange (ETDEWEB)

Haemmerling, Jens

2011-06-07

We study the emergence of collective dynamics in the integrable Hamiltonian system of two finite ensembles of coupled harmonic oscillators. After identification of a collective degree of freedom, the Hamiltonian is mapped onto a model of Caldeira-Leggett type, where the collective coordinate is coupled to an internal bath of phonons. In contrast to the usual Caldeira-Leggett model, the bath in the present case is part of the system. We derive an equation of motion for the collective coordinate which takes the form of a damped harmonic oscillator. We show that the distribution of quantum transition strengths induced by the collective mode is determined by its classical dynamics. This allows us to derive the spreading for the collective coordinate from first principles. After that we study the interplay between collective and incoherent single-particle motion in a model of two chains of particles whose interaction comprises a non-integrable part. In the perturbative regime, but for a general form of the interaction, we calculate the Fourier transform of the time correlation for the collective coordinate. We obtain the remarkable result that it always has a unique semi-classical interpretation. We show this by a proper renormalization procedure which also allows us to map the non-integrable system to the integrable model of Caldeira-Leggett-type considered previously in which the bath is part of the system.

Robotic Exoskeletons: A Perspective for the Rehabilitation of Arm Coordination in Stroke Patients

Science.gov (United States)

Jarrassé, Nathanaël; Proietti, Tommaso; Crocher, Vincent; Robertson, Johanna; Sahbani, Anis; Morel, Guillaume; Roby-Brami, Agnès

2014-01-01

Upper-limb impairment after stroke is caused by weakness, loss of individual joint control, spasticity, and abnormal synergies. Upper-limb movement frequently involves abnormal, stereotyped, and fixed synergies, likely related to the increased use of sub-cortical networks following the stroke. The flexible coordination of the shoulder and elbow joints is also disrupted. New methods for motor learning, based on the stimulation of activity-dependent neural plasticity have been developed. These include robots that can adaptively assist active movements and generate many movement repetitions. However, most of these robots only control the movement of the hand in space. The aim of the present text is to analyze the potential of robotic exoskeletons to specifically rehabilitate joint motion and particularly inter-joint coordination. First, a review of studies on upper-limb coordination in stroke patients is presented and the potential for recovery of coordination is examined. Second, issues relating to the mechanical design of exoskeletons and the transmission of constraints between the robotic and human limbs are discussed. The third section considers the development of different methods to control exoskeletons: existing rehabilitation devices and approaches to the control and rehabilitation of joint coordinations are then reviewed, along with preliminary clinical results available. Finally, perspectives and future strategies for the design of control mechanisms for rehabilitation exoskeletons are discussed. PMID:25520638

Impact of a School Health Coordinator Intervention on Health-Related School Policies and Student Behavior

Science.gov (United States)

O'Brien, Liam M.; Polacsek, Michele; MacDonald, Pamela B.; Ellis, Jacqueline; Berry, Susan; Martin, Maurice

2010-01-01

Background: Health-related, school-based interventions may serve to prevent disease and improve academic performance. The Healthy Maine Partnerships (HMP) initiative funded local school health coordinators (SHCs) as a part of Maine's Coordinated School Health Program (CSHP) beginning in January 2001. SHCs established school health leadership teams…

Absence of direction-specific cross-modal visual-auditory adaptation in motion-onset event-related potentials.

Science.gov (United States)

Grzeschik, Ramona; Lewald, Jörg; Verhey, Jesko L; Hoffmann, Michael B; Getzmann, Stephan

2016-01-01

Adaptation to visual or auditory motion affects within-modality motion processing as reflected by visual or auditory free-field motion-onset evoked potentials (VEPs, AEPs). Here, a visual-auditory motion adaptation paradigm was used to investigate the effect of visual motion adaptation on VEPs and AEPs to leftward motion-onset test stimuli. Effects of visual adaptation to (i) scattered light flashes, and motion in the (ii) same or in the (iii) opposite direction of the test stimulus were compared. For the motion-onset VEPs, i.e. the intra-modal adaptation conditions, direction-specific adaptation was observed--the change-N2 (cN2) and change-P2 (cP2) amplitudes were significantly smaller after motion adaptation in the same than in the opposite direction. For the motion-onset AEPs, i.e. the cross-modal adaptation condition, there was an effect of motion history only in the change-P1 (cP1), and this effect was not direction-specific--cP1 was smaller after scatter than after motion adaptation to either direction. No effects were found for later components of motion-onset AEPs. While the VEP results provided clear evidence for the existence of a direction-specific effect of motion adaptation within the visual modality, the AEP findings suggested merely a motion-related, but not a direction-specific effect. In conclusion, the adaptation of veridical auditory motion detectors by visual motion is not reflected by the AEPs of the present study. © 2015 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

Motor Coordination Dynamics Underlying Graphic Motion in 7- to 11-Year-Old Children

Science.gov (United States)

Danna, Jeremy; Enderli, Fabienne; Athenes, Sylvie; Zanone, Pier-Giorgio

2012-01-01

Using concepts and tools of a dynamical system approach in order to understand motor coordination underlying graphomotor skills, the aim of the current study was to establish whether the basic coordination dynamics found in adults is already established in children at elementary school, when handwriting is trained and eventually acquired. In the…

Special relativity and the Karhunen-Loeve expansion of Brownian motion

International Nuclear Information System (INIS)

Maccone, C.

1987-01-01

The connection between special relativity and the theory of the time-rescaled Gaussian stochastic processes is brought to light. It is given the general expression of the Karhunen-Loewe expansion for the Brownian motion whose variable is the proper time. The relevant eigenfunctions are proved to be Bessel functions, and their stability is discussed. The eigenvalues are shown to be the zeros of certain linear combinations of the Bessel functions and their partials. The energy distribution of such a class of processes is investigated, and it is given explicit formulae for both its mean value and variance. Finally it is studied in detail the Karhumen-Loeve expansion for a case of relativistic decelerated motion whose analysis is feasible in closed form

Supersymmetries and constants of motion in Taub-NUT spinning space

International Nuclear Information System (INIS)

Vaman, D.; Visinescu, M.

1998-01-01

Models of relativistic particles with spin have been proposed for a long time. The models involving only conventional coordinates are called classical, while the models involving anticommuting coordinates are generally called pseudo-classical. In this paper, the relativistic spin one half particle models involving anticommuting vectorial degrees of freedom, which are usually called the spinning particles, are considered. Spinning particles are in some sense the classical limit of the Dirac particles. After the first quantization these new anticommuting variables are mapped into the Dirac matrices and they disappear from the theory. In the present paper, the motion of pseudo-classical spinning particles in curved spaces is investigated and the relevant equations of motion are investigated. The generalized Killing equations for the configuration space of spinning particles (spinning spaces) are discussed and the constants of motion are derived in terms of the solutions of these equations. We also analysed the motion of pseudo-classical spinning particles in the Euclidean Taub-NUT space. The generalized Killing equations for this spinning space are examined and derivation of the constants of motion in terms of the Killing-Yano tensors is described. The equations obtained for the special case of motion on cone are solved. This case represents an extension of the scalar particle motions in the usual Taub-NUT space in which the orbits are conic sections. An explicit exact solution is given. In spite of its simplicity, this solution occurs to be far from trivial. (authors)

Test-particle motion in the nonsymmetric gravitation theory

International Nuclear Information System (INIS)

Moffat, J.W.

1987-01-01

A derivation of the motion of test particles in the nonsymmetric gravitational theory (NGT) is given using the field equations in the presence of matter. The motion of the particle is governed by the Christoffel symbols, which are formed from the symmetric part of the fundamental tensor g/sub μ//sub ν/, as well as by a tensorial piece determined by the skew part of the contracted curvature tensor R/sub μ//sub ν/. Given the energy-momentum tensor for a perfect fluid and the definition of a test particle in the NGT, the equations of motion follow from the conservation laws. The tensorial piece in the equations of motion describes a new force in nature that acts on the conserved charge in a body. Particles that carry this new charge do not follow geodesic world lines in the NGT, whereas photons do satisfy geodesic equations of motion and the equivalence principle of general relativity. Astronomical predictions, based on the exact static, spherically symmetric solution of the field equations in a vacuum and the test-particle equations of motion, are derived in detail. The maximally extended coordinates that remove the event-horizon singularities in the static, spherically symmetric solution are presented. It is shown how an inward radially falling test particle can be prevented from forming an event horizon for a value greater than a specified critical value of the source charge. If a test particle does fall through an event horizon, then it must continue to fall until it reaches the singularity at r = 0

Test-particle motion in the nonsymmetric gravitation theory

Science.gov (United States)

Moffat, J. W.

1987-06-01

A derivation of the motion of test particles in the nonsymmetric gravitational theory (NGT) is given using the field equations in the presence of matter. The motion of the particle is governed by the Christoffel symbols, which are formed from the symmetric part of the fundamental tensor gμν, as well as by a tensorial piece determined by the skew part of the contracted curvature tensor Rμν. Given the energy-momentum tensor for a perfect fluid and the definition of a test particle in the NGT, the equations of motion follow from the conservation laws. The tensorial piece in the equations of motion describes a new force in nature that acts on the conserved charge in a body. Particles that carry this new charge do not follow geodesic world lines in the NGT, whereas photons do satisfy geodesic equations of motion and the equivalence principle of general relativity. Astronomical predictions, based on the exact static, spherically symmetric solution of the field equations in a vacuum and the test-particle equations of motion, are derived in detail. The maximally extended coordinates that remove the event-horizon singularities in the static, spherically symmetric solution are presented. It is shown how an inward radially falling test particle can be prevented from forming an event horizon for a value greater than a specified critical value of the source charge. If a test particle does fall through an event horizon, then it must continue to fall until it reaches the singularity at r=0.

Success and Failure of Parliamentary Motions: A Social Dilemma Approach.

Science.gov (United States)

Popping, Roel; Wittek, Rafael

2015-01-01

Parliamentary motions are a vital and frequently used element of political control in democratic regimes. Despite their high incidence and potential impact on the political fate of a government and its policies, we know relatively little about the conditions under which parliamentary motions are likely to be accepted or rejected. Current collective decision-making models use a voting power framework in which power and influence of the involved parties are the main predictors. We propose an alternative, social dilemma approach, according to which a motion's likelihood to be accepted depends on the severity of the social dilemma underlying the decision issue. Actor- and dilemma-centered hypotheses are developed and tested with data from a stratified random sample of 822 motions that have been voted upon in the Dutch Parliament between September 2009 and February 2011. The social dilemma structure of each motion is extracted through content coding, applying a cognitive mapping technique developed by Anthony, Heckathorn and Maser. Logistic regression analyses are in line with both, actor-centered and social-dilemma centered approaches, though the latter show stronger effect sizes. Motions have a lower chance to be accepted if voting potential is low, the proposer is not from the voting party, and if the problem underlying the motion reflects a prisoner's dilemma or a pure competition game as compared to a coordination game. The number of proposing parties or a battle of the sexes structure does not significantly affect the outcome.

Inertial Measures of Motion for Clinical Biomechanics: Comparative Assessment of Accuracy under Controlled Conditions - Effect of Velocity

Science.gov (United States)

Lebel, Karina; Boissy, Patrick; Hamel, Mathieu; Duval, Christian

2013-01-01

Background Inertial measurement of motion with Attitude and Heading Reference Systems (AHRS) is emerging as an alternative to 3D motion capture systems in biomechanics. The objectives of this study are: 1) to describe the absolute and relative accuracy of multiple units of commercially available AHRS under various types of motion; and 2) to evaluate the effect of motion velocity on the accuracy of these measurements. Methods The criterion validity of accuracy was established under controlled conditions using an instrumented Gimbal table. AHRS modules were carefully attached to the center plate of the Gimbal table and put through experimental static and dynamic conditions. Static and absolute accuracy was assessed by comparing the AHRS orientation measurement to those obtained using an optical gold standard. Relative accuracy was assessed by measuring the variation in relative orientation between modules during trials. Findings Evaluated AHRS systems demonstrated good absolute static accuracy (mean error < 0.5o) and clinically acceptable absolute accuracy under condition of slow motions (mean error between 0.5o and 3.1o). In slow motions, relative accuracy varied from 2o to 7o depending on the type of AHRS and the type of rotation. Absolute and relative accuracy were significantly affected (p<0.05) by velocity during sustained motions. The extent of that effect varied across AHRS. Interpretation Absolute and relative accuracy of AHRS are affected by environmental magnetic perturbations and conditions of motions. Relative accuracy of AHRS is mostly affected by the ability of all modules to locate the same global reference coordinate system at all time. Conclusions Existing AHRS systems can be considered for use in clinical biomechanics under constrained conditions of use. While their individual capacity to track absolute motion is relatively consistent, the use of multiple AHRS modules to compute relative motion between rigid bodies needs to be optimized according to

The importance of multidisciplinary teamwork and team climate for relational coordination among teams delivering care to older patients

NARCIS (Netherlands)

J.M. Hartgerink (Jacqueline); J.M. Cramm (Jane); T.J.E.M. Bakker (Ton); A.M. van Eijsden (A.); J.P. Mackenbach (Johan); A.P. Nieboer (Anna)

2013-01-01

textabstractAim: To identify predictors of relational coordination among professionals delivering care to older patients. Background: Relational coordination is known to enhance quality of care in hospitals. The underlying mechanisms, however, remain poorly understood. Design: This cross-sectional

Kinematics of relative motion of test particles in general relativity

International Nuclear Information System (INIS)

Bazanski, S.L.

1977-01-01

A detailed mathematical study of the concept of geodesic deviation in pseudo-riemannian geometry is presented. A generalization of this concept to geodesic deviations of a higher order is then introduced and the second geodesic deviation is investigated in some detail. A geometric interpretation of the set of generalized geodesic deviations is given and applied in general relativity to determine a covariant and local description (with a desired order of accuracy) of test motions which take place in a certain finite neighbourhood of a given world line of an observer. The proper time evolution of two other objects related to geodesic deviation is also discussed: the space separation vector and the telescopic vector. This last name is given here to a field of null vectors along observer's world line which always point towards the same adjacent world line. The telescopic equations allow to determine the evolution of the frequency shift of electromagnetic radiation sent from and received on neighbouring world lines. On the basis of these equations also certain relations have been derived which connect the frequencies or frequency shifts with the curvature of space-time

Teamwork methods for accountable care: relational coordination and TeamSTEPPS®.

Science.gov (United States)

Gittell, Jody Hoffer; Beswick, Joanne; Goldmann, Don; Wallack, Stanley S

2015-01-01

To deliver greater value in the accountable care context, the Institute of Medicine argues for a culture of teamwork at multiple levels--across professional and organizational siloes and with patients and their families and communities. The logic of performance improvement is that data are needed to target interventions and to assess their impact. We argue that efforts to build teamwork will benefit from teamwork measures that provide diagnostic information regarding the current state and teamwork interventions that can respond to the opportunities identified in the current state. We identify teamwork measures and teamwork interventions that are validated and that can work across multiple levels of teamwork. We propose specific ways to combine them for optimal effectiveness. We review measures of teamwork documented by Valentine, Nembhard, and Edmondson and select those that they identified as satisfying the four criteria for psychometric validation and as being unbounded and therefore able to measure teamwork across multiple levels. We then consider teamwork interventions that are widely used in the U.S. health care context, are well validated based on their association with outcomes, and are capable of working at multiple levels of teamwork. We select the top candidate in each category and propose ways to combine them for optimal effectiveness. We find relational coordination is a validated multilevel teamwork measure and TeamSTEPPS® is a validated multilevel teamwork intervention and propose specific ways for the relational coordination measure to enhance the TeamSTEPPS intervention. Health care systems and change agents seeking to respond to the challenges of accountable care can use TeamSTEPPS as a validated multilevel teamwork intervention methodology, enhanced by relational coordination as a validated multilevel teamwork measure with diagnostic capacity to pinpoint opportunities for improving teamwork along specific dimensions (e.g., shared knowledge

Modes of uncontrolled rotational motion of the Progress M-29M spacecraft

Science.gov (United States)

Belyaev, M. Yu.; Matveeva, T. V.; Monakhov, M. I.; Rulev, D. N.; Sazonov, V. V.

2018-01-01

We have reconstructed the uncontrolled rotational motion of the Progress M-29M transport cargo spacecraft in the single-axis solar orientation mode (the so-called sunward spin) and in the mode of the gravitational orientation of a rotating satellite. The modes were implemented on April 3-7, 2016 as a part of preparation for experiments with the DAKON convection sensor onboard the Progress spacecraft. The reconstruction was performed by integral statistical techniques using the measurements of the spacecraft's angular velocity and electric current from its solar arrays. The measurement data obtained in a certain time interval have been jointly processed using the least-squares method by integrating the equations of the spacecraft's motion relative to the center of mass. As a result of processing, the initial conditions of motion and parameters of the mathematical model have been estimated. The motion in the sunward spin mode is the rotation of the spacecraft with an angular velocity of 2.2 deg/s about the normal to the plane of solar arrays; the normal is oriented toward the Sun or forms a small angle with this direction. The duration of the mode is several orbit passes. The reconstruction has been performed over time intervals of up to 1 h. As a result, the actual rotational motion of the spacecraft relative to the Earth-Sun direction was obtained. In the gravitational orientation mode, the spacecraft was rotated about its longitudinal axis with an angular velocity of 0.1-0.2 deg/s; the longitudinal axis executed small oscillated relative to the local vertical. The reconstruction of motion relative to the orbital coordinate system was performed in time intervals of up to 7 h using only the angularvelocity measurements. The measurements of the electric current from solar arrays were used for verification.

A review of some basic aspects related to integration of airplane’s equations of motion

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Dan TURCANU

2017-09-01

Full Text Available Numerical integration of the airplane’s equations of motion has long been considered among the most fundamental calculations in airplane’s analysis. Numerical algorithms have been implemented and experimentally validated. However, the need for superior speed and accuracy is still very topical, as, nowadays, various optimization algorithms rely heavily on data generated from the integration of the equations of motion and having access to larger amounts of data can increase the quality of the optimization. Now, for a number of decades, engineers have relied heavily on commercial codes based on automatically selected integration steps. However, optimally chosen constant integration steps can save time and allows for larger numbers of integrations to be performed. Yet, the basic papers that presented the fundamentals of numerical integration, as applied to airplane’s equations of motion are nowadays not easy to locate. Consequently, this paper presents a review of basic aspects related to the integration of airplane’s equation of motion. The discussion covers fundamentals of longitudinal and lateral-directional motion as well as the implementation of some numerical integration methods. The relation between numerical integration steps, accuracy, computational resource usage, numerical stability and their relation with the parameters describing the dynamic response of the airplane is considered and suggestions are presented for a faster yet accurate numerical integration.

Plasticity of intermediate mechanics students’ coordinate system choice

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Eleanor C. Sayre

2008-11-01

Full Text Available We investigate the interplay between mathematics and physics resources in intermediate mechanics students. In the mechanics course, the selection and application of coordinate systems is a consistent thread. At the University of Maine, students often start the course with a strong preference to use Cartesian coordinates, in accordance with their prior physics and mathematics classes. In small-group interviews and in homework help sessions, we ask students to define a coordinate system and set up the equations of motion for a simple pendulum for which polar coordinates are more appropriate. We analyze video data from several encounters using a combination of Process/Object theory and Resource Theory. We find that students sometimes persist in using an inappropriate Cartesian system. Furthermore, students often derive (rather than recall the details of the polar coordinate system, indicating that their knowledge is far from solid. To describe our work more precisely, we define a scale of plasticity and several heuristics for defining resources and their plasticity.

Motion detection and correction for dynamic 15O-water myocardial perfusion PET studies

International Nuclear Information System (INIS)

Naum, Alexandru; Laaksonen, Marko S.; Oikonen, Vesa; Teraes, Mika; Jaervisalo, Mikko J.; Knuuti, Juhani; Tuunanen, Helena; Nuutila, Pirjo; Kemppainen, Jukka

2005-01-01

Patient motion during dynamic PET studies is a well-documented source of errors. The purpose of this study was to investigate the incidence of frame-to-frame motion in dynamic 15 O-water myocardial perfusion PET studies, to test the efficacy of motion correction methods and to study whether implementation of motion correction would have an impact on the perfusion results. We developed a motion detection procedure using external radioactive skin markers and frame-to-frame alignment. To evaluate motion, marker coordinates inside the field of view were determined in each frame for each study. The highest number of frames with identical spatial coordinates during the study were defined as ''non-moved''. Movement was considered present if even one marker changed position, by one pixel/frame compared with reference, in one axis, and such frames were defined as ''moved''. We tested manual, in-house-developed motion correction software and an automatic motion correction using a rigid body point model implemented in MIPAV (Medical Image Processing, Analysis and Visualisation) software. After motion correction, remaining motion was re-analysed. Myocardial blood flow (MBF) values were calculated for both non-corrected and motion-corrected datasets. At rest, patient motion was found in 18% of the frames, but during pharmacological stress the fraction increased to 45% and during physical exercise it rose to 80%. Both motion correction algorithms significantly decreased (p<0.006) the number of moved frames and the amplitude of motion (p<0.04). Motion correction significantly increased MBF results during bicycle exercise (p<0.02). At rest or during adenosine infusion, the motion correction had no significant effects on MBF values. Significant motion is a common phenomenon in dynamic cardiac studies during adenosine infusion but especially during exercise. Applying motion correction for the data acquired during exercise clearly changed the MBF results, indicating that motion

Hybrid Architecture for Coordination of AGVs in FMS

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Eduardo G. Hernandez-Martinez

2014-03-01

Full Text Available This paper presents a hybrid control architecture that coordinates the motion of groups of automated guided vehicles in flexible manufacturing systems. The high-level control is based on a Petri net model, using the industrial standard ISA-95, obtaining a task-based coordination of equipment and storage considering process restrictions, logical precedences, shared resources and the assignment of robots to move workpieces individually or in subgroups. On the other hand, in the low-level control, three basic control laws are designed for unicycle-type robots in order to achieve desired formation patterns and marching behaviours, avoiding inter-robot collisions. The control scheme combines the task assignment for the robots obtained from the discrete-event model and the implementation of formation and marching continuous control laws applied to the motion of the mobile robots. The hybrid architecture is implemented and validated for the case of a flexible manufacturing system and four mobile robots using a virtual reality platform.

Orbit covariance propagation via quadratic-order state transition matrix in curvilinear coordinates

Science.gov (United States)

Hernando-Ayuso, Javier; Bombardelli, Claudio

2017-09-01

In this paper, an analytical second-order state transition matrix (STM) for relative motion in curvilinear coordinates is presented and applied to the problem of orbit uncertainty propagation in nearly circular orbits (eccentricity smaller than 0.1). The matrix is obtained by linearization around a second-order analytical approximation of the relative motion recently proposed by one of the authors and can be seen as a second-order extension of the curvilinear Clohessy-Wiltshire (C-W) solution. The accuracy of the uncertainty propagation is assessed by comparison with numerical results based on Monte Carlo propagation of a high-fidelity model including geopotential and third-body perturbations. Results show that the proposed STM can greatly improve the accuracy of the predicted relative state: the average error is found to be at least one order of magnitude smaller compared to the curvilinear C-W solution. In addition, the effect of environmental perturbations on the uncertainty propagation is shown to be negligible up to several revolutions in the geostationary region and for a few revolutions in low Earth orbit in the worst case.

Doppler frequency in interplanetary radar and general relativity

Science.gov (United States)

Mcvittie, G. C.

1972-01-01

The change of frequency of an interplanetary radar signal sent from the earth to another planet or to a space probe is worked out according to general relativity. The Schwarzschild spacetime is employed and its null geodesics control the motion of the signals. Exact Doppler frequency formulas are derived for one-way and two-way radar in terms of an arbitrary Schwarzschild radial coordinate. A reduction to the special relativity case is used to interpret the formulas in terms of the relative radial velocity of emitter and target. The general relativity corrections are worked out approximately for each of three possible Schwarzschild radial coordinates, and a numerical example is given. The amount of the correction is different according as one or the other of the Schwarzschild coordinates is identified with the radius vector deduced from classical celestial mechanics. The identification problem is discussed.

Movement coordination and differential kinematics of the cervical and thoracic spines in people with chronic neck pain.

Science.gov (United States)

Tsang, Sharon M H; Szeto, Grace P Y; Lee, Raymond Y W

2013-07-01

Research on the kinematics and inter-regional coordination of movements between the cervical and thoracic spines in motion adds to our understanding of the performance and interplay of these spinal regions. The purpose of this study was to examine the effects of chronic neck pain on the three-dimensional kinematics and coordination of the cervical and thoracic spines during active movements of the neck. Three-dimensional spinal kinematics and movement coordination between the cervical, upper thoracic, and lower thoracic spines were examined by electromagnetic motion sensors in thirty-four individuals with chronic neck pain and thirty-four age- and gender-matched asymptomatic subjects. All subjects performed a set of free active neck movements in three anatomical planes in sitting position and at their own pace. Spinal kinematic variables (angular displacement, velocity, and acceleration) of the three defined regions, and movement coordination between regions were determined and compared between the two groups. Subjects with chronic neck pain exhibited significantly decreased cervical angular velocity and acceleration of neck movement. Cross-correlation analysis revealed consistently lower degrees of coordination between the cervical and upper thoracic spines in the neck pain group. The loss of coordination was most apparent in angular velocity and acceleration of the spine. Assessment of the range of motion of the neck is not sufficient to reveal movement dysfunctions in chronic neck pain subjects. Evaluation of angular velocity and acceleration and movement coordination should be included to help develop clinical intervention strategies to promote restoration of differential kinematics and movement coordination. Copyright © 2013 Elsevier Ltd. All rights reserved.

PEER NGA-East Overview: Development of a Ground Motion Characterization Model (Ground Motion Prediction Equations) for Central and Eastern North America

Science.gov (United States)

Goulet, C. A.; Abrahamson, N. A.; Al Atik, L.; Atkinson, G. M.; Bozorgnia, Y.; Graves, R. W.; Kuehn, N. M.; Youngs, R. R.

2017-12-01

The Next Generation Attenuation project for Central and Eastern North America (CENA), NGA-East, is a major multi-disciplinary project coordinated by the Pacific Earthquake Engineering Research Center (PEER). The project was co-sponsored by the U.S. Nuclear Regulatory Commission (NRC), the U.S. Department of Energy (DOE), the Electric Power Research Institute (EPRI) and the U.S. Geological Survey (USGS). NGA-East involved a large number of participating researchers from various organizations in academia, industry and government and was carried-out as a combination of 1) a scientific research project and 2) a model-building component following the NRC Seismic Senior Hazard Analysis Committee (SSHAC) Level 3 process. The science part of the project led to several data products and technical reports while the SSHAC component aggregated the various results into a ground motion characterization (GMC) model. The GMC model consists in a set of ground motion models (GMMs) for median and standard deviation of ground motions and their associated weights, combined into logic-trees for use in probabilistic seismic hazard analyses (PSHA). NGA-East addressed many technical challenges, most of them related to the relatively small number of earthquake recordings available for CENA. To resolve this shortcoming, the project relied on ground motion simulations to supplement the available data. Other important scientific issues were addressed through research projects on topics such as the regionalization of seismic source, path and attenuation of motions, the treatment of variability and uncertainties and on the evaluation of site effects. Seven working groups were formed to cover the complexity and breadth of topics in the NGA-East project, each focused on a specific technical area. This presentation provides an overview of the NGA-East research project and its key products.

Manned space flight activities and sensory-motor coordinations; Yujin uchu katsudo tono hito no kankaku undokei

Energy Technology Data Exchange (ETDEWEB)

Koga, K. [Nagoya Univ., Nagoya (Japan). Research Inst. of Environmental Medicine

1996-03-05

With an objective to elucidate relationship between human functions related to gravity in space and the gravity, simultaneous measurement was carried out on impulsive eyeball motions and antigravity muscles. The measurement used a non-polarized electrode mounted on a prescribed position on skin. The subject is a spacecraft crew who was subjected to an experiment in space in 1992. Data obtained during the flight were analyzed, and the following findings were obtained: the eyeball motions are performed accurately in terms of space and time; potential time relative to the target appearance time showed greater variation than in control conditions on the ground; activities of trapezius muscle as an antigravity muscle were suppressed, and electric discharge from the muscle was small even if the head is moved; the eyeballs move in coordination with the head when viewing an object; microgravity environment showed a head motion with very little muscle discharge possible as in the case where the head is held unmoved; and difference in motion patterns between the antigravity muscles and non-antigravity muscles may exist as a possible cause of spacesickness in addition to the conventional sensory disagreement theory. 32 refs., 6 figs.

Static analysis of large-scale multibody system using joint coordinates and spatial algebra operator.

Science.gov (United States)

Omar, Mohamed A

2014-01-01

Initial transient oscillations inhibited in the dynamic simulations responses of multibody systems can lead to inaccurate results, unrealistic load prediction, or simulation failure. These transients could result from incompatible initial conditions, initial constraints violation, and inadequate kinematic assembly. Performing static equilibrium analysis before the dynamic simulation can eliminate these transients and lead to stable simulation. Most exiting multibody formulations determine the static equilibrium position by minimizing the system potential energy. This paper presents a new general purpose approach for solving the static equilibrium in large-scale articulated multibody. The proposed approach introduces an energy drainage mechanism based on Baumgarte constraint stabilization approach to determine the static equilibrium position. The spatial algebra operator is used to express the kinematic and dynamic equations of the closed-loop multibody system. The proposed multibody system formulation utilizes the joint coordinates and modal elastic coordinates as the system generalized coordinates. The recursive nonlinear equations of motion are formulated using the Cartesian coordinates and the joint coordinates to form an augmented set of differential algebraic equations. Then system connectivity matrix is derived from the system topological relations and used to project the Cartesian quantities into the joint subspace leading to minimum set of differential equations.

Parkinson-related changes of activation in visuomotor brain regions during perceived forward self-motion.

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Anouk van der Hoorn

Full Text Available Radial expanding optic flow is a visual consequence of forward locomotion. Presented on screen, it generates illusionary forward self-motion, pointing at a close vision-gait interrelation. As particularly parkinsonian gait is vulnerable to external stimuli, effects of optic flow on motor-related cerebral circuitry were explored with functional magnetic resonance imaging in healthy controls (HC and patients with Parkinson's disease (PD. Fifteen HC and 22 PD patients, of which 7 experienced freezing of gait (FOG, watched wide-field flow, interruptions by narrowing or deceleration and equivalent control conditions with static dots. Statistical parametric mapping revealed that wide-field flow interruption evoked activation of the (pre-supplementary motor area (SMA in HC, which was decreased in PD. During wide-field flow, dorsal occipito-parietal activations were reduced in PD relative to HC, with stronger functional connectivity between right visual motion area V5, pre-SMA and cerebellum (in PD without FOG. Non-specific 'changes' in stimulus patterns activated dorsolateral fronto-parietal regions and the fusiform gyrus. This attention-associated network was stronger activated in HC than in PD. PD patients thus appeared compromised in recruiting medial frontal regions facilitating internally generated virtual locomotion when visual motion support falls away. Reduced dorsal visual and parietal activations during wide-field optic flow in PD were explained by impaired feedforward visual and visuomotor processing within a magnocellular (visual motion functional chain. Compensation of impaired feedforward processing by distant fronto-cerebellar circuitry in PD is consistent with motor responses to visual motion stimuli being either too strong or too weak. The 'change'-related activations pointed at covert (stimulus-driven attention.

Dynamics and control of Lorentz-augmented spacecraft relative motion

CERN Document Server

Yan, Ye; Yang, Yueneng

2017-01-01

This book develops a dynamical model of the orbital motion of Lorentz spacecraft in both unperturbed and J2-perturbed environments. It explicitly discusses three kinds of typical space missions involving relative orbital control: spacecraft hovering, rendezvous, and formation flying. Subsequently, it puts forward designs for both open-loop and closed-loop control schemes propelled or augmented by the geomagnetic Lorentz force. These control schemes are entirely novel and represent a significantly departure from previous approaches.

Collective circular motion in synchronized and balanced formations with second-order rotational dynamics

Science.gov (United States)

Jain, Anoop; Ghose, Debasish

2018-01-01

This paper considers collective circular motion of multi-agent systems in which all the agents are required to traverse different circles or a common circle at a prescribed angular velocity. It is required to achieve these collective motions with the heading angles of the agents synchronized or balanced. In synchronization, the agents and their centroid have a common velocity direction, while in balancing, the movement of agents causes the location of the centroid to become stationary. The agents are initially considered to move at unit speed around individual circles at different angular velocities. It is assumed that the agents are subjected to limited communication constraints, and exchange relative information according to a time-invariant undirected graph. We present suitable feedback control laws for each of these motion coordination tasks by considering a second-order rotational dynamics of the agent. Simulations are given to illustrate the theoretical findings.

Quantum field theory in stationary coordinate systems

International Nuclear Information System (INIS)

Pfautsch, J.D.

1981-01-01

Quantum field theory is examined in stationary coordinate systems in Minkowski space. Preliminary to quantization of the scalar field, all of the possible stationary coordinate systems in flat spacetime are classified and explicitly constructed. Six distinct classes of such systems are found. Of these six, three have (identical) event horizons associated with them and five have Killing horizons. Two classes have distinct Killing and event horizons, with an intervening region analogous to the ergosphere in rotating black holes. Particular representatives of each class are selected for subsequent use in the quantum field theory. The scalar field is canonically quantized and a vacuum defined in each of the particular coordinate systems chosen. The vacuum states can be regarded as adapted to the six classes of stationary motions. There are only two vacuum states found, the Minkowski vacuum in those coordinate systems without event horizons and the Fulling vacuum in those with event horizons. The responses of monopole detectors traveling along stationary world lines are calculated in both the Minkowski and Fulling vacuums. The responses for each class of motions are distinct from those for every other class. A vacuum defined by the response of a detector must therefore not be equivalent in general to a vacuum defined by canonical quantization. Quantization of the scalar field within a rotating wedge is examined. It has not been possible to construct mode functions satisfying appropriate boundary conditions on the surface of the wedge. The asymptotic form of the renormalized stress tensor near the surfaces had been calculated and is found to include momentum terms which represent a circulation of energy within the wedge

The volume of fluid method in spherical coordinates

NARCIS (Netherlands)

Janse, A.M.C.; Janse, A.M.C.; Dijk, P.E.; Kuipers, J.A.M.

2000-01-01

The volume of fluid (VOF) method is a numerical technique to track the developing free surfaces of liquids in motion. This method can, for example, be applied to compute the liquid flow patterns in a rotating cone reactor. For this application a spherical coordinate system is most suited. The novel

Interpersonal movement coordination in jointly moving a rocking board

NARCIS (Netherlands)

Bosga, J.; Meulenbroek, R.G.J.; Cuijpers, R.H.

2010-01-01

In this study, we investigate how two persons (dyads) coordinate their movements when performing cyclical motion patterns on a rocking board. In keeping with the Leading Joint Hypothesis (Dounskaia, 2005), the movement dynamics of the collaborating participants were expected to display features of a

A microscopic theory of the nuclear collective motion

International Nuclear Information System (INIS)

Baranger, M.

1975-01-01

A microscopic theory of the nuclear collective model is reviewed, discussions being concentrated, mainly, on the shape motion. An adiabatic time dependent Hartree-Fock method is used. Kinetic energy using the cranking model is obtained. The generator coordinate method is discussed [pt

Annotated Bibliography on Relative Motion

Science.gov (United States)

1992-03-01

displace the sheave, and motive means operating the power ram. Preferably, the power run is subjected to i constant upward pneumatic force to provide...NCIEI- Report N- 1187 (Oct 1971). The theory is de\\ eloped for the swinging rmotion induced in a wire suspended load due to the hori7zontal motion of a

North America-Greenland-Eurasian relative motions: implications for circum-arctic tectonic reconstructions

Energy Technology Data Exchange (ETDEWEB)

Rowley, D.B.; Lottes, A.L.; Ziegler, A.M.

1985-02-01

The Mesozoic-Cenozoic tectonic evolution of the Circum-Arctic region is based on constraints imposed by (1) relative motion histories of the three major plates (North America, Greenland, and Eurasia) and a number of smaller pieces, and (2) distribution and age of sutures, accretionary prisms, volcanic arcs, fold-thrust belts, stretched continental crust, strike-slip faults, and ocean floor. The authors conclude that: (1) North America and Eurasia remained relatively fixed to each other until the latest Cretaceous-Paleocene opening of the Labrador Sea-Baffin Bay and Greenland-Norwegian and Eurasian basins (earlier convergence between North America and Eurasia in the Bering Sea region shown on many reconstructions are artifacts of incorrect plate reconstructions); (2) the North Slope-Seward-Chukotka block has constituted an isthmus connection between North America and northeast Asia since at least the middle Paleozoic and did not rotate away from the Canadian Arctic; (3) the Canada basin opened behind a clockwise-rotating Alpha Cordillera-Mendeleyev ridge arc during the Early to middle Cretaceous and consumed older, Paleozoic(.) Makarov basin ocean floor (the Chukchi cap is a detached continental fragment derived from the Beaufort Sea; the North Slope Arctic margin is a left-lateral transform fault associated with the opening of the Canada basin); and (4) the Nares Strait fault has a net relative displacement of approximately 25 km, but actual motion between Greenland and northern Ellesmere was about 250 km of strongly transpressive motion that resulted in the Eurekan and Svalbardian orogenies.

The coordinate system transformation of a serial kinematic structures and use in the derivation of systems motion equations

Directory of Open Access Journals (Sweden)

Zátopek Jiří

2016-01-01

Full Text Available This text discusses the use of transformation matrices to determine the motion equations of the complex mechanical structure. Use of the transformation matrix does not apply only to motion equations but has the general use in relative positions determine of objects in the 3D space. Analysed model is divided into seven physical objects, the transformation matrix and the corresponding inertia/pseudo-inertia matrix is included in each of them. This matrices are strictly necessary to the system dynamic description using the matrix form of Lagrange Equations of the Second Type. Another possibility to use the transformation matrix is shown in the camera system measurement. Model was designed in 3D CAD system SolidWorks, MATLAB was used for the mathematical calculations.

INTER-JOINT COORDINATION IN PRODUCING KICKING VELOCITY OF TAEKWONDO KICKS

Directory of Open Access Journals (Sweden)

Young Kwan Kim

2011-03-01

Full Text Available The purpose of this study was to investigate joint kinematics of the kicking leg in Taekwondo and to examine the role of inter-joint coordination of the leg in producing the kicking velocity. A new inter-joint coordination index that encompasses three- dimensional hip and knee motions, was defined and applied to the joint kinematic results. Twelve elite Taekwondo athletes participated in this study and performed the back kick, thrashing kick, turning-back kick and roundhouse kick. Our results indicate that the back kick utilized a combination of hip and knee extension to produce the kicking velocity, and was characterized by a pushlike movement. The thrashing kick and turning-back kick utilized a greater degree of hip abduction than the roundhouse kick and back kick, and included complicated knee motions. The new index successfully categorized the thrashing kick and turning-back kick into a push-throw continuum, indicating a change from negative index (opposite direction to positive index (same direction of hip and knee motions at the end of the movement. This strategy of push-throw continuum increases the kicking velocity at the moment of impact by applying a throwlike movement pattern

IGS polar motion measurement accuracy

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Jim Ray

2017-11-01

Full Text Available We elaborate an error budget for the long-term accuracy of IGS (International Global Navigation Satellite System Service polar motion estimates, concluding that it is probably about 25–30 μas (1-sigma overall, although it is not possible to quantify possible contributions (mainly annual that might transfer directly from aliases of subdaily rotational tide errors. The leading sources are biases arising from the need to align daily, observed terrestrial frames, within which the pole coordinates are expressed and which are continuously deforming, to the secular, linear international reference frame. Such biases are largest over spans longer than about a year. Thanks to the very large number of IGS tracking stations, the formal covariance errors are much smaller, around 5 to 10 μas. Large networks also permit the systematic frame-related errors to be more effectively minimized but not eliminated. A number of periodic errors probably also influence polar motion results, mainly at annual, GPS (Global Positioning System draconitic, and fortnightly periods, but their impact on the overall error budget is unlikely to be significant except possibly for annual tidal aliases. Nevertheless, caution should be exercised in interpreting geophysical excitations near any of the suspect periods.

Kinematic geometry of a line trajectory in spatial motion

Energy Technology Data Exchange (ETDEWEB)

Al-Ghefari, Reem A. [King Abdulaziz University, Jeddah (Saudi Arabia); Abdel-Baky, Rashad A. [University of Assiut, Assiu (Egypt)

2015-09-15

This paper derives the equations of line-trajectory in spatial motion by means of the E. Study dual-line coordinates. A special emphasis goes to the second-order motion properties for deriving a new proof of the Disteli formulae. As an application concise explicit expressions of the inflection line congruence are directly obtained. Also, a new metric is developed and used to investigate the geometrical properties and kinematics of line trajectory as well as Disteli axis. Finally, a theoretical expressions of point trajectories with special values of velocity and acceleration, which can be considered as a form Euler-Savary equation, for spherical and planar motions are discussed.

Motion-guided attention promotes adaptive communications during social navigation.

Science.gov (United States)

Lemasson, B H; Anderson, J J; Goodwin, R A

2013-03-07

Animals are capable of enhanced decision making through cooperation, whereby accurate decisions can occur quickly through decentralized consensus. These interactions often depend upon reliable social cues, which can result in highly coordinated activities in uncertain environments. Yet information within a crowd may be lost in translation, generating confusion and enhancing individual risk. As quantitative data detailing animal social interactions accumulate, the mechanisms enabling individuals to rapidly and accurately process competing social cues remain unresolved. Here, we model how motion-guided attention influences the exchange of visual information during social navigation. We also compare the performance of this mechanism to the hypothesis that robust social coordination requires individuals to numerically limit their attention to a set of n-nearest neighbours. While we find that such numerically limited attention does not generate robust social navigation across ecological contexts, several notable qualities arise from selective attention to motion cues. First, individuals can instantly become a local information hub when startled into action, without requiring changes in neighbour attention level. Second, individuals can circumvent speed-accuracy trade-offs by tuning their motion thresholds. In turn, these properties enable groups to collectively dampen or amplify social information. Lastly, the minority required to sway a group's short-term directional decisions can change substantially with social context. Our findings suggest that motion-guided attention is a fundamental and efficient mechanism underlying collaborative decision making during social navigation.

Online prediction of respiratory motion: multidimensional processing with low-dimensional feature learning

International Nuclear Information System (INIS)

Ruan, Dan; Keall, Paul

2010-01-01

Accurate real-time prediction of respiratory motion is desirable for effective motion management in radiotherapy for lung tumor targets. Recently, nonparametric methods have been developed and their efficacy in predicting one-dimensional respiratory-type motion has been demonstrated. To exploit the correlation among various coordinates of the moving target, it is natural to extend the 1D method to multidimensional processing. However, the amount of learning data required for such extension grows exponentially with the dimensionality of the problem, a phenomenon known as the 'curse of dimensionality'. In this study, we investigate a multidimensional prediction scheme based on kernel density estimation (KDE) in an augmented covariate-response space. To alleviate the 'curse of dimensionality', we explore the intrinsic lower dimensional manifold structure and utilize principal component analysis (PCA) to construct a proper low-dimensional feature space, where kernel density estimation is feasible with the limited training data. Interestingly, the construction of this lower dimensional representation reveals a useful decomposition of the variations in respiratory motion into the contribution from semiperiodic dynamics and that from the random noise, as it is only sensible to perform prediction with respect to the former. The dimension reduction idea proposed in this work is closely related to feature extraction used in machine learning, particularly support vector machines. This work points out a pathway in processing high-dimensional data with limited training instances, and this principle applies well beyond the problem of target-coordinate-based respiratory-based prediction. A natural extension is prediction based on image intensity directly, which we will investigate in the continuation of this work. We used 159 lung target motion traces obtained with a Synchrony respiratory tracking system. Prediction performance of the low-dimensional feature learning

Equations of motion for free-flight systems of rotating-translating bodies

International Nuclear Information System (INIS)

Hodapp, A.E. Jr.

1976-09-01

General vector differential equations of motion are developed for a system of rotating-translating, unbalanced, constant mass bodies. Complete flexibility is provided in placement of the reference coordinates within the system of bodies and in placement of body fixed axes within each body. Example cases are presented to demonstrate the ease in reduction of these equations to the equations of motion for systems of interest

Does relative body fat influence the Movement ABC-2 assessment in children with and without developmental coordination disorder?

Science.gov (United States)

Faught, Brent E; Demetriades, Stephen; Hay, John; Cairney, John

2013-12-01

Developmental coordination disorder (DCD) is a condition that results in an impairment of gross and/or fine motor coordination. Compromised motor coordination contributes to lower levels of physical activity, which is associated with elevated body fat. The impact of elevated body fat on motor coordination diagnostic assessments in children with DCD has not been established. The purpose of this study was to determine if relative body fat influences performance on the Movement Assessment Battery for Children, 2nd Edition (MABC-2) test items in children with and without DCD. A nested case-control, design was conducted within the Physical Health Activity Study Team longitudinal cohort study. The MABC-2 was used to assess motor coordination to categorize cases and matched controls. Relative body fat was assessed using whole body air displacement plethysmography. Relative body fat was negatively associated with the MABC-2 "balance" subcategory after adjusting for physical activity and DCD status. Relative body fat did not influence the subcategories of "manual dexterity" or "aiming and catching". Item analysis of the three balance tasks indicated that relative body fat significantly influences both "2-board balance" and "zig-zag hopping", but not "walking heel-toe backwards". Children with higher levels of relative body fat do not perform as well on the MABC-2, regardless of whether the have DCD or not. Dynamic balance test items are most negatively influenced by body fat. Health practitioners and researchers should be aware that body fat can influence results when interpreting MABC-2 test scores. Crown Copyright © 2013. Published by Elsevier Ltd. All rights reserved.

Vection and visually induced motion sickness: How are they related?

Directory of Open Access Journals (Sweden)

Behrang eKeshavarz

2015-04-01

Full Text Available The occurrence of visually induced motion sickness has been frequently linked to the sensation of illusory self-motion (so-called vection, however, the precise nature of this relationship is still not fully understood. To date, it is still a matter of debate whether or not vection is a necessary prerequisite for visually induced motion sickness (VIMS. That is, can there be visually induced motion sickness without any sensation of self-motion? In this paper, we will describe the possible nature of this relationship, review the literature that may speak to this relationship (including theoretical accounts of vection and VIMS, and offer suggestions with respect to operationally defining and reporting these phenomena in future.

An Assessment of a Low-Cost Visual Tracking System (VTS) to Detect and Compensate for Patient Motion During SPECT

Science.gov (United States)

McNamara, Joseph E.; Bruyant, Philippe; Johnson, Karen; Feng, Bing; Lehovich, Andre; Gu, Songxiang; Gennert, Michael A.; King, Michael A.

2008-06-01

Patient motion is inevitable in SPECT and PET due to the lengthy period of time patients are imaged and patient motion can degrade diagnostic accuracy. The goal of our studies is to perfect a methodology for tracking and correcting patient motion when it occurs. In this paper we report on enhancements to the calibration, camera stability, accuracy of motion tracking, and temporal synchronization of a low-cost visual tracking system (VTS) we are developing. The purpose of the VTS is to track the motion of retro-reflective markers on stretchy bands wrapped about the chest and abdomen of patients. We have improved the accuracy of 3D spatial calibration by using a MATLAB optical camera calibration package with a planar calibration pattern. This allowed us to determine the intrinsic and extrinsic parameters for stereo-imaging with our CCD cameras. Locations in the VTS coordinate system are transformed to the SPECT coordinate system by a VTS/SPECT mapping using a phantom of 7 retro-reflective spheres each filled with a drop of Tc99m. We switched from pan, tilt and zoom (PTZ) network cameras to fixed network cameras to reduce the amount of camera drift. The improved stability was verified by tracking the positions of fixed retro-reflective markers on a wall. The ability of our VTS to track movement, on average, with sub-millimeter and sub-degree accuracy was established with the 7-sphere phantom for 1 cm vertical and axial steps as well as for an arbitrary rotation and translation. The difference in the time of optical image acquisition as decoded from the image headers relative to synchronization signals sent to the SPECT system was used to establish temporal synchrony between optical and list-mode SPECT acquisition. Two experiments showed better than 100 ms agreement between VTS and SPECT observed motion for three axial translations. We were able to track 3 reflective markers on an anthropomorphic phantom with a precision that allowed us to correct motion such that no

open-quotes Metaclose quotes-rigid motions and frames of reference

International Nuclear Information System (INIS)

Bel, L.; Llosa, J.

1995-01-01

We define the open-quotes metaclose quotes-rigid motions as particular classes of time-like congruences which are solutions of intrinsically defined partial differential equations that generalize Born's conditions. We consider in particular two hierarchies of such congruences. The first one is a geometrically motivated direct generalization of the symmetry concept inherent in Born congruences. The second one is an indirect generalization based on the conditions which guarantee the existence of a particular class of adapted coordinates of space, named quo-harmonic coordinates, whose definition is akin to the definition of harmonic coordinates but which differs from it in an essential point

Multimodal Perception and Multicriterion Control of Nested Systems. 1; Coordination of Postural Control and Vehicular Control

Science.gov (United States)

Riccio, Gary E.; McDonald, P. Vernon

1998-01-01

The purpose of this report is to identify the essential characteristics of goal-directed whole-body motion. The report is organized into three major sections (Sections 2, 3, and 4). Section 2 reviews general themes from ecological psychology and control-systems engineering that are relevant to the perception and control of whole-body motion. These themes provide an organizational framework for analyzing the complex and interrelated phenomena that are the defining characteristics of whole-body motion. Section 3 of this report applies the organization framework from the first section to the problem of perception and control of aircraft motion. This is a familiar problem in control-systems engineering and ecological psychology. Section 4 examines an essential but generally neglected aspect of vehicular control: coordination of postural control and vehicular control. To facilitate presentation of this new idea, postural control and its coordination with vehicular control are analyzed in terms of conceptual categories that are familiar in the analysis of vehicular control.

A practical head tracking system for motion correction in neurological SPECT and PET

International Nuclear Information System (INIS)

Fulton, R.R.; Eberl, S.; Meikle, S.; Hutton, B.F.; Braun, M.

1998-01-01

Full text: Patient motion during data acquisition can degrade the quality of SPECT and PET images. Techniques for motion correction in neurological studies in both modalities based on continuous monitoring of head position have been proposed. However difficulties in developing suitable head tracking systems have so far impeded clinical implementations. We have developed a head tracking system based on the mechanical ADL-1 tracker (Shooting Star Technology, Rosedale, Canada) on a Trionix triple-head SPECT camera A software driver running on a SUN Sparc host computer communicates with the tracker over a serial line providing up to 300 updates per second with angular and positional resolutions of 0.05 degrees and 0.2 mm respectively. The SUN Sparc workstation which acquires the SPECT study also communicates with the tracker, eliminating synchronisation problems. For motion correction, the motion parameters provided by the tracker within its own coordinate system must be converted to the camera's coordinate system. The conversion requires knowledge of the rotational relationships between the two coordinate systems and the displacement of their origins, both of which are determined from a calibration procedure. The tracker has been tested under clinical SPECT imaging conditions with a 3D Hoffman brain phantom. Multiple SPECT acquisitions were performed. After each acquisition the phantom was moved to a new position and orientation. Motion parameters reported by the tracker for each applied movement were compared with those obtained by applying an automated image registration program to the sequential reconstructed studies. Maximum differences were < 0.5 degrees and < 2mm, within the expected errors of the registration procedure. We conclude that this tracking system will be suitable for clinical evaluation of motion correction in SPECT and PET

A viscoelastic model of the correlation between respiratory lung tumour motion and an external abdominal signal

International Nuclear Information System (INIS)

Cavan, A.E.; Wilson, P.L.; Meyer, J.; Berbeco, R.I.

2010-01-01

Full text: Accuracy of radiotherapy treatment of lung cancer is limited by respiratory induced tumour motion. Compensation for this motion is required to increase treatment efficacy. The lung tumour motion is related to motion of an external abdominal marker, but a reliable model of this correlation is essential. Three viscoelastic systems were developed, in order to determine the best model and analyse its effectiveness on clinical data. Three 1D viscoelastic systems (a spring and dash pot in parallel, series and a combination) were developed and compared using a simulated breathing pattern. The most effective model was applied to 60 clinical data sets (consisting of co-ordinates of tumour and abdominal motion) from multiple treatment fractions of ten patients. The model was optimised for each data set, and efficacy determined by calculating the root mean square (RMS) error between the mo elled position and the actual tumour motion. Upon application to clinical data the parallel configuration achieved an average RMS error of 0.95 mm (superior-inferior direction). The model had patient specific parameters, and displayed good consistency over extended treatment periods. The model ha dled amplitude, frequency and baseline variations of the input signal, and phase shifts between tumour and abdominal motions. This study has shown that a viscoelastic model can be used to cor relate internal lung tumour motion with an external abdominal signal. The ability to handle breathing pattern in'egularities is comparable or better than previous models. Extending the model to a full 3D, pr dictive system could allow clinical implementation for radiotherapy.

Relative dynamics and motion control of nanosatellite formation flying

Science.gov (United States)

Pimnoo, Ammarin; Hiraki, Koju

2016-04-01

Orbit selection is a necessary factor in nanosatellite formation mission design/meanwhile, to keep the formation, it is necessary to consume fuel. Therefore, the best orbit design for nanosatellite formation flying should be one that requires the minimum fuel consumption. The purpose of this paper is to analyse orbit selection with respect to the minimum fuel consumption, to provide a convenient way to estimate the fuel consumption for keeping nanosatellite formation flying and to present a simplified method of formation control. The formation structure is disturbed by J2 gravitational perturbation and other perturbing accelerations such as atmospheric drag. First, Gauss' Variation Equations (GVE) are used to estimate the essential ΔV due to the J2 perturbation and atmospheric drag. The essential ΔV presents information on which orbit is good with respect to the minimum fuel consumption. Then, the linear equations which account for J2 gravitational perturbation of Schweighart-Sedwick are presented and used to estimate the fuel consumption to maintain the formation structure. Finally, the relative dynamics motion is presented as well as a simplified motion control of formation structure by using GVE.

Lie symmetry and the generalized Hojman conserved quantity of Nielsen equations for a variable mass holonomic system of relative motion

International Nuclear Information System (INIS)

Zhang Mei-Ling; Wang Xiao-Xiao; Xie Yin-Li; Jia Li-Qun; Sun Xian-Ting

2011-01-01

Lie symmetry and the generalized Hojman conserved quantity of Nielsen equations for a variable mass holonomic system of relative motion are studied. The determining equation of Lie symmetry of Nielsen equations for a variable mass holonomic system of relative motion under the infinitesimal transformations of groups is given. The expression of generalized Hojman conserved quantity deduced directly from Lie symmetry for a variable mass holonomic system of relative motion is obtained. An example is given to illustrate the application of the results. (general)

Turbulence characterization by studying laser beam wandering in a differential tracking motion setup

Science.gov (United States)

Pérez, Darío G.; Zunino, Luciano; Gulich, Damián; Funes, Gustavo; Garavaglia, Mario

2009-09-01

The Differential Image Motion Monitor (DIMM) is a standard and widely used instrument for astronomical seeing measurements. The seeing values are estimated from the variance of the differential image motion over two equal small pupils some distance apart. The twin pupils are usually cut in a mask on the entrance pupil of the telescope. As a differential method, it has the advantage of being immune to tracking errors, eliminating erratic motion of the telescope. The Differential Laser Tracking Motion (DLTM) is introduced here inspired by the same idea. Two identical laser beams are propagated through a path of air in turbulent motion, at the end of it their wander is registered by two position sensitive detectors-at a count of 800 samples per second. Time series generated from the difference of the pair of centroid laser beam coordinates is then analyzed using the multifractal detrended fluctuation analysis. Measurements were performed at the laboratory with synthetic turbulence: changing the relative separation of the beams for different turbulent regimes. The dependence, with respect to these parameters, and the robustness of our estimators is compared with the non-differential method. This method is an improvement with respect to previous approaches that study the beam wandering.

Exploring the pedagogic relation - Supporting six-year-olds in making sense of physical motion

OpenAIRE

Annika Åkerblom

2015-01-01

This article explores how verbal relations between child and researcher may support the child’s reasoning and making sense of physical motion. In an earlier study, 64 children aged 6–14 participated in one-to-one reflective dialogues. Some of them developed their reasoning during the dialogue, and used an exploring approach to make sense of physical motion. For the present study, 6 transcripts were re-analyzed concerning the interplay between the researcher and the 6-year-olds who used this a...

Protocol to assess the neurophysiology associated with multi-segmental postural coordination

International Nuclear Information System (INIS)

Lomond, Karen V; Henry, Sharon M; Jacobs, Jesse V; Hitt, Juvena R; Horak, Fay B; Cohen, Rajal G; Schwartz, Daniel; Dumas, Julie A; Naylor, Magdalena R; Watts, Richard; DeSarno, Michael J

2013-01-01

Anticipatory postural adjustments (APAs) stabilize potential disturbances to posture caused by movement. Impaired APAs are common with disease and injury. Brain functions associated with generating APAs remain uncertain due to a lack of paired tasks that require similar limb motion from similar postural orientations, but differ in eliciting an APA while also being compatible with brain imaging techniques (e.g., functional magnetic resonance imaging; fMRI). This study developed fMRI-compatible tasks differentiated by the presence or absence of APAs during leg movement. Eighteen healthy subjects performed two leg movement tasks, supported leg raise (SLR) and unsupported leg raise (ULR), to elicit isolated limb motion (no APA) versus multi-segmental coordination patterns (including APA), respectively. Ground reaction forces under the feet and electromyographic activation amplitudes were assessed to determine the coordination strategy elicited for each task. Results demonstrated that the ULR task elicited a multi-segmental coordination that was either minimized or absent in the SLR task, indicating that it would serve as an adequate control task for fMRI protocols. A pilot study with a single subject performing each task in an MRI scanner demonstrated minimal head movement in both tasks and brain activation patterns consistent with an isolated limb movement for the SLR task versus multi-segmental postural coordination for the ULR task. (note)

Bilateral coordination and gait symmetry after body-weight supported treadmill training for persons with chronic stroke.

Science.gov (United States)

Combs, Stephanie A; Dugan, Eric L; Ozimek, Elicia N; Curtis, Amy B

2013-04-01

Locomotor interventions are commonly assessed using functional outcomes, but these outcomes provide limited information about changes toward recovery or compensatory mechanisms. The study purposes were to examine changes in gait symmetry and bilateral coordination following body-weight supported treadmill training in individuals with chronic hemiparesis due to stroke and to compare findings to participants without disability. Nineteen participants with stroke (>6 months) who ambulated between 0.4 and 0.8 m/s and 22 participants without disability were enrolled in this repeated-measures study. The stroke group completed 24 intervention sessions over 8 weeks with 20 minutes of walking/session. The non-disabled group served as a comparison for describing changes in symmetry and coordination. Bilateral 3-dimensional motion analysis and gait speed were assessed across 3 time points (pre-test, immediate post-test, and 6-month retention). Continuous relative phase was used to evaluate bilateral coordination (thigh-thigh, shank-shank, foot-foot) and gait symmetry was assessed with spatiotemporal ratios (step length, swing time, stance time). Significant improvements in continuous relative phase (shank-shank and foot-foot couplings) were found at post-test and retention for the stroke group. Significant differences in spatiotemporal symmetry ratios were not found over time. Compared to the non-disabled group, changes in bilateral coordination moved in the direction of normal recovery. Most measures of continuous relative phase were more responsive to change after training than the spatiotemporal ratios. After body-weight supported treadmill training, the stroke group made improvements toward recovery of normal bilateral coordination. Bilateral coordination and gait symmetry measures may assess different aspects of gait. Copyright © 2013 Elsevier Ltd. All rights reserved.

Gravity Cues Embedded in the Kinematics of Human Motion Are Detected in Form-from-Motion Areas of the Visual System and in Motor-Related Areas.

Science.gov (United States)

Cignetti, Fabien; Chabeauti, Pierre-Yves; Menant, Jasmine; Anton, Jean-Luc J J; Schmitz, Christina; Vaugoyeau, Marianne; Assaiante, Christine

2017-01-01

The present study investigated the cortical areas engaged in the perception of graviceptive information embedded in biological motion (BM). To this end, functional magnetic resonance imaging was used to assess the cortical areas active during the observation of human movements performed under normogravity and microgravity (parabolic flight). Movements were defined by motion cues alone using point-light displays. We found that gravity modulated the activation of a restricted set of regions of the network subtending BM perception, including form-from-motion areas of the visual system (kinetic occipital region, lingual gyrus, cuneus) and motor-related areas (primary motor and somatosensory cortices). These findings suggest that compliance of observed movements with normal gravity was carried out by mapping them onto the observer's motor system and by extracting their overall form from local motion of the moving light points. We propose that judgment on graviceptive information embedded in BM can be established based on motor resonance and visual familiarity mechanisms and not necessarily by accessing the internal model of gravitational motion stored in the vestibular cortex.

Effects on ground motion related to spatial variability

International Nuclear Information System (INIS)

Vanmarcke, E.H.

1987-01-01

Models of the spectral content and the space-time correlation structure of strong earthquake ground motion are combined with transient random vibration analysis to yield site-specific response spectra that can account for the effect of local spatial averaging of the ground motion across a rigid foundation of prescribed size. The methodology is presented with reference to sites in eastern North America, although the basic approach is applicable to other seismic regions provided the source and attenuation parameters are regionally adjusted. Parameters in the spatial correlation model are based on data from the SMART-I accelerograph array, and the sensitivity of response spectra reduction factors with respect to these parameters is examined. The starting point of the analysis is the Fourier amplitude spectrum of site displacement expresses as a function of earthquake source parameters and source-to-site distance. The bedrock acceleration spectral density function at a point, derived from the displacement spectrum, is modified to account for anelastic attenuation, and where appropriate, for local soil effects and/or local spatial averaging across a foundation. Transient random vibration analysis yields approximate analytical expressions for median ground motion amplitudes and median response spectra of an earthquake defined in terms of its spectral density function and strong motion duration. The methodology is illustrated for three events characterized by their m b magnitude and epicentral distance. The focus in this paper is on the stochastic response prediction methodology enabling explicit accounting for strong motion duration and the effect of local spatial averaging on response spectra. The numerical examples enable a preliminary assessment of the reduction of response spectral amplitudes attributable to local spatial averaging across rigid foundations of different sizes. 36 refs

Normal form of particle motion under the influence of an ac dipole

Directory of Open Access Journals (Sweden)

R. Tomás

2002-05-01

Full Text Available ac dipoles in accelerators are used to excite coherent betatron oscillations at a drive frequency close to the tune. These beam oscillations may last arbitrarily long and, in principle, there is no significant emittance growth if the ac dipole is adiabatically turned on and off. Therefore the ac dipole seems to be an adequate tool for nonlinear diagnostics provided the particle motion is well described in the presence of the ac dipole and nonlinearities. Normal forms and Lie algebra are powerful tools to study the nonlinear content of an accelerator lattice. In this article a way to obtain the normal form of the Hamiltonian of an accelerator with an ac dipole is described. The particle motion to first order in the nonlinearities is derived using Lie algebra techniques. The dependence of the Hamiltonian terms on the longitudinal coordinate is studied showing that they vary differently depending on the ac dipole parameters. The relation is given between the lines of the Fourier spectrum of the turn-by-turn motion and the Hamiltonian terms.

Classical collisions of protons with hydrogen atoms. [Equations of motion, cross sections, C code, FORTRAN, moments of inertia

Energy Technology Data Exchange (ETDEWEB)

Banks, D; Hughes, P E; Percival, I C [Queen Mary Coll., London (UK); Barnes, K S [National Health Service Operational Research Group, Royal Institute of Public Administration, Reading, Berkshire, UK; Richards, D [Open Univ., Milton Keynes (UK); Valentine, N A [Digital Equipment Corporation, Bilton House, Uxbridge Road, Ealing, London, UK; Wilson, Mc B [Glasgow Univ. (UK). Dept. of Natural Philosophy

1977-01-01

The program solves the equations of motion for the interaction of 3 charged particles, obtaining final states in terms of initial states, and energy transfers, angles of ejection, and final cartesian co-ordinates of relative motion. Using a Monte Carlo method on many orbits total ionization and charge transfer cross sections, integral energy transfer cross sections and moments of energy transfers are estimated. Facilities are provided for obtaining angular distributions, momentum transfer cross sections and for comparison with various approximate classical theories. The equations of motion are solved using stepwise fourth-order Runge-Kutta integration with automatic steplength change. Selection of initial conditions is determined by the user, usually as a statistical distribution determined by a pseudorandom number subroutine. Classical representation theory and transformation methods are extensively used.

Isolating integrals of the motion for stellar orbits in a rotating galactic bar

International Nuclear Information System (INIS)

Vandervoort, P.O.

1979-01-01

The study of the equilibrium of a rotating galactic bar requires an enumeration of the isolating integrals of the motion of a star in the prevailing gravitational field. In general, Jacobi's integral is the only exact isolating integral known. This paper describes a search for an additional isolating integral for orbits confined to a plane perpendicular to the axis of the bar's rotation. It is shown that, in general, the equations of motion admit an additional integral exactly which is a nonhomogeneous quadratic form in the momenta of the star only if (1) the gravitational potential is axisymmetric, (2) the gravitational potential is harmonic, or (3) the bar does not rotate and the gravitational potential is separable in elliptic coordinates. A formal integral of the motion is constructed for orbits in a slightly anharmonic potential. Numerical solutions of the equations of motion for orbits in a slightly anharmonic potential behave as if there were indeed an additional isolating integral, and that behavior is represented very well in terms of the formal integral. If the rotation of the bar is rapid and/or the nonaxisymmetry of the bar is weak, then the additional integral restricts the motion of a star in much the same way that the angular momentum restricts motion in an axisymmetric potential. Conversely, if the rotation of the bar is slow and/or the nonaxisymmetry of the bar is strong, then the additional integral restricts the motion in much the same way that the difference of the separable energies would if the motion were separable in Cartesian coordinates

H∞ control for path tracking of autonomous underwater vehicle motion

Directory of Open Access Journals (Sweden)

Lin-Lin Wang

2015-05-01

Full Text Available In order to simplify the design of path tracking controller and solve the problem relating to nonlinear dynamic model of autonomous underwater vehicle motion planning, feedback linearization method is first adopted to transform the nonlinear dynamic model into an equivalent pseudo-linear dynamic model in horizontal coordinates. Then considering wave disturbance effect, mixed-sensitivity method of H∞ robust control is applied to design state-feedback controller for this equivalent dynamic model. Finally, control law of pseudo-linear dynamic model is transformed into state (surge velocity and yaw angular rate tracking control law of nonlinear dynamic model through inverse coordinate transformation. Simulation indicates that autonomous underwater vehicle path tracking is successfully implemented with this proposed method, and the influence of parameter variation in autonomous underwater vehicle dynamic model on its tracking performance is reduced by H∞ controller. All the results show that the method proposed in this article is effective and feasible.

The importance of multidisciplinary teamwork and team climate for relational coordination among teams delivering care to older patients

OpenAIRE

Hartgerink, Jacqueline; Cramm, Jane; Bakker, Ton; Eijsden, A.; Mackenbach, Johan; Nieboer, Anna

2013-01-01

textabstractAim: To identify predictors of relational coordination among professionals delivering care to older patients. Background: Relational coordination is known to enhance quality of care in hospitals. The underlying mechanisms, however, remain poorly understood. Design: This cross-sectional study was part of a larger evaluation study examining the opportunity to prevent loss of function in older patients due to hospitalization in the Netherlands. Methods: This study was performed in sp...

The importance of multidisciplinary teamwork and team climate for relational coordination among teams delivering care to older patients

OpenAIRE

J.M. Hartgerink; J.M. Cramm; T.J.E.M. Bakker; A.M. van Eijsden; J.P. Mackenbach; A.P. Nieboer

2013-01-01

Aim To identify predictors of relational coordination among professionals delivering care to older patients. Background Relational coordination is known to enhance quality of care in hospitals. The underlying mechanisms, however, remain poorly understood. Design This cross-sectional study was part of a larger evaluation study examining the opportunity to prevent loss of function in older patients due to hospitalization in the Netherlands. Methods This study was performed in spring 2010 among ...

Simulation of spatiotemporal CT data sets using a 4D MRI-based lung motion model.

Science.gov (United States)

Marx, Mirko; Ehrhardt, Jan; Werner, René; Schlemmer, Heinz-Peter; Handels, Heinz

2014-05-01

Four-dimensional CT imaging is widely used to account for motion-related effects during radiotherapy planning of lung cancer patients. However, 4D CT often contains motion artifacts, cannot be used to measure motion variability, and leads to higher dose exposure. In this article, we propose using 4D MRI to acquire motion information for the radiotherapy planning process. From the 4D MRI images, we derive a time-continuous model of the average patient-specific respiratory motion, which is then applied to simulate 4D CT data based on a static 3D CT. The idea of the motion model is to represent the average lung motion over a respiratory cycle by cyclic B-spline curves. The model generation consists of motion field estimation in the 4D MRI data by nonlinear registration, assigning respiratory phases to the motion fields, and applying a B-spline approximation on a voxel-by-voxel basis to describe the average voxel motion over a breathing cycle. To simulate a patient-specific 4D CT based on a static CT of the patient, a multi-modal registration strategy is introduced to transfer the motion model from MRI to the static CT coordinates. Differences between model-based estimated and measured motion vectors are on average 1.39 mm for amplitude-based binning of the 4D MRI data of three patients. In addition, the MRI-to-CT registration strategy is shown to be suitable for the model transformation. The application of our 4D MRI-based motion model for simulating 4D CT images provides advantages over standard 4D CT (less motion artifacts, radiation-free). This makes it interesting for radiotherapy planning.

Modification of Motion Perception and Manual Control Following Short-Durations Spaceflight

Science.gov (United States)

Wood, S. J.; Vanya, R. D.; Esteves, J. T.; Rupert, A. H.; Clement, G.

2011-01-01

Adaptive changes during space flight in how the brain integrates vestibular cues with other sensory information can lead to impaired movement coordination and spatial disorientation following G-transitions. This ESA-NASA study was designed to examine both the physiological basis and operational implications for disorientation and tilt-translation disturbances following short-duration spaceflights. The goals of this study were to (1) examine the effects of stimulus frequency on adaptive changes in motion perception during passive tilt and translation motion, (2) quantify decrements in manual control of tilt motion, and (3) evaluate vibrotactile feedback as a sensorimotor countermeasure.

Processive motions of MreB micro-filaments coordinate cell wall growth

Science.gov (United States)

Garner, Ethan

2012-02-01

Rod-shaped bacteria elongate by the action of cell-wall synthesis complexes linked to underlying dynamic MreB filaments, but how these proteins function to allow continued elongation as a rod remains unknown. To understand how the movement of these filaments relates to cell wall synthesis, we characterized the dynamics of MreB and the cell wall elongation machinery using high-resolution particle tracking in Bacillus subtilis. We found that both MreB and the elongation machinery move in linear paths across the cell, moving at similar rates (˜20nm / second) and angles to the cell body, suggesting they function as single complexes. These proteins move circumferentially around the cell, principally perpendicular to its length. We find that the motions of these complexes are independent, as they can pause and reverse,and also as nearby complexes move independently in both directions across one surface of the cell. Inhibition of cell wall synthesis with antibiotics or depletions in the cell wall synthesis machinery blocked MreB movement, suggesting that the cell wall synthetic machinery is the motor in this system. We propose that bacteria elongate by the uncoordinated, circumferential movements of synthetic complexes that span the plasma membrane and insert radial hoops of new peptidoglycan during their transit.

Correlation of horizontal and vertical components of strong ground motion for response-history analysis of safety-related nuclear facilities

Energy Technology Data Exchange (ETDEWEB)

Huang, Yin-Nan, E-mail: ynhuang@ntu.edu.tw [Dept. of Civil Engineering, National Taiwan University, No. 1, Sec. 4, Roosevelt Rd., Taipei 10617, Taiwan (China); Yen, Wen-Yi, E-mail: b01501059@ntu.edu.tw [Dept. of Civil Engineering, National Taiwan University, No. 1, Sec. 4, Roosevelt Rd., Taipei 10617, Taiwan (China); Whittaker, Andrew S., E-mail: awhittak@buffalo.edu [Dept. of Civil, Structural and Environmental Engineering, MCEER, State University of New York at Buffalo, Buffalo, NY 14260 (United States)

2016-12-15

Highlights: • The correlation of components of ground motion is studied using 1689 sets of records. • The data support an upper bound of 0.3 on the correlation coefficient. • The data support the related requirement in the upcoming edition of ASCE Standard 4. - Abstract: Design standards for safety-related nuclear facilities such as ASCE Standard 4-98 and ASCE Standard 43-05 require the correlation coefficient for two orthogonal components of ground motions for response-history analysis to be less than 0.3. The technical basis of this requirement was developed by Hadjian three decades ago using 50 pairs of recorded ground motions that were available at that time. In this study, correlation coefficients for (1) two horizontal components, and (2) the vertical component and one horizontal component, of a set of ground motions are computed using records from a ground-motion database compiled recently for large-magnitude shallow crustal earthquakes. The impact of the orientation of the orthogonal horizontal components on the correlation coefficient of ground motions is discussed. The rules in the forthcoming edition of ASCE Standard 4 for the correlation of components in a set of ground motions are shown to be reasonable.

Universal current-velocity relation of skyrmion motion in chiral magnets

Science.gov (United States)

Iwasaki, Junichi; Mochizuki, Masahito; Nagaosa, Naoto

2013-03-01

Current-driven motion of the magnetic domain wall requires large critical current density jc ~109 -1012 A/m2, at which the joule heating is a serious problem. The skyrmions recently discovered in chiral magnets, on the other hand, have much smaller critical current of jc ~105 -106 A/m2. We present a numerical simulation of the Landau-Lifshitz-Gilbert equation, which reveals a remarkably robust and universal current-velocity relation of the slyrmion motion driven by the spin transfer torque unaffected by either impurities or nonadiabatic effect in sharp contrast to the case of domain wall or spin helix (HL). Simulation results are analyzed using a theory based on Thiele's equation, and it is concluded that this surprising behavior is due to the Magnus force and flexible shape-deformation of individual skyrmions and skyrmion crystal (SkX), which enable them to avoid pinning centers and then weaken the net pinning force. Dynamical deformation of SkX leads to the fluctuation of Bragg peak with large amplitude, which can be detected by the recent neutron-scattering experiment.

Human-directed local autonomy for motion guidance and coordination in an intelligent manufacturing system

Science.gov (United States)

Alford, W. A.; Kawamura, Kazuhiko; Wilkes, Don M.

1997-12-01

This paper discusses the problem of integrating human intelligence and skills into an intelligent manufacturing system. Our center has jointed the Holonic Manufacturing Systems (HMS) Project, an international consortium dedicated to developing holonic systems technologies. One of our contributions to this effort is in Work Package 6: flexible human integration. This paper focuses on one activity, namely, human integration into motion guidance and coordination. Much research on intelligent systems focuses on creating totally autonomous agents. At the Center for Intelligent Systems (CIS), we design robots that interact directly with a human user. We focus on using the natural intelligence of the user to simplify the design of a robotic system. The problem is finding ways for the user to interact with the robot that are efficient and comfortable for the user. Manufacturing applications impose the additional constraint that the manufacturing process should not be disturbed; that is, frequent interacting with the user could degrade real-time performance. Our research in human-robot interaction is based on a concept called human directed local autonomy (HuDL). Under this paradigm, the intelligent agent selects and executes a behavior or skill, based upon directions from a human user. The user interacts with the robot via speech, gestures, or other media. Our control software is based on the intelligent machine architecture (IMA), an object-oriented architecture which facilitates cooperation and communication among intelligent agents. In this paper we describe our research testbed, a dual-arm humanoid robot and human user, and the use of this testbed for a human directed sorting task. We also discuss some proposed experiments for evaluating the integration of the human into the robot system. At the time of this writing, the experiments have not been completed.

The Southern Proper Motion Program. IV. The SPM4 Catalog

Science.gov (United States)

Girard, Terrence M.; van Altena, William F.; Zacharias, Norbert; Vieira, Katherine; Casetti-Dinescu, Dana I.; Castillo, Danilo; Herrera, David; Lee, Young Sun; Beers, Timothy C.; Monet, David G.; López, Carlos E.

2011-07-01

We present the fourth installment of the Yale/San Juan Southern Proper Motion Catalog, SPM4. The SPM4 contains absolute proper motions, celestial coordinates, and B, V photometry for over 103 million stars and galaxies between the south celestial pole and -20° declination. The catalog is roughly complete to V = 17.5 and is based on photographic and CCD observations taken with the Yale Southern Observatory's double astrograph at Cesco Observatory in El Leoncito, Argentina. The proper-motion precision, for well-measured stars, is estimated to be 2-3 mas yr-1, depending on the type of second-epoch material. At the bright end, proper motions are on the International Celestial Reference System by way of Hipparcos Catalog stars, while the faint end is anchored to the inertial system using external galaxies. Systematic uncertainties in the absolute proper motions are on the order of 1 mas yr-1.

Intra- and Interpersonal Movement Coordination in Jointly Moving a Rocking Board

NARCIS (Netherlands)

Bosga, J.; Meulenbroek, R.G.J.; Cuijpers, R.H.

2010-01-01

In this study, we investigate how two persons (dyads) coordinate their movements when performing cyclical motion patterns on a rocking board. In keeping with the Leading Joint Hypothesis (Dounskaia, 2005), the movement dynamics of the collaborating participants were expected to display features of a

Towards Coordination and Control of Multi-robot Systems

DEFF Research Database (Denmark)

Quottrup, Michael Melholt

This thesis focuses on control and coordination of mobile multi-robot systems (MRS). MRS can often deal with tasks that are difficult to be accomplished by a single robot. One of the challenges is the need to control, coordinate and synchronize the operation of several robots to perform some...... specified task. This calls for new strategies and methods which allow the desired system behavior to be specified in a formal and succinct way. Two different frameworks for the coordination and control of MRS have been investigated. Framework I - A network of robots is modeled as a network of multi...... a requirement specification in Computational Tree Logic (CTL) for a network of robots. The result is a set of motion plans for the robots which satisfy the specification. Framework II - A framework for controller synthesis for a single robot with respect to requirement specification in Linear-time Temporal...

A Counseling Model for Self-Relation Coordination for Chinese Clients with Interpersonal Conflicts

Science.gov (United States)

Chen, Ping-Hwa

2009-01-01

This article proposes a self-relation coordination counseling model for contemporary Taiwanese clients. The model is based on an analysis of the interpersonal disturbances of people suffering from conflict resulting from the coexistence of a Confucian cultural heritage and Western values. The goal of the proposed model is to help clients…

Coordination of dual robot arms using kinematic redundancy

Science.gov (United States)

Suh, Il Hong; Shin, Kang G.

1988-01-01

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

Relative Attitude Estimation for a Uniform Motion and Slowly Rotating Noncooperative Spacecraft

Directory of Open Access Journals (Sweden)

Liu Zhang

2017-01-01

Full Text Available This paper presents a novel relative attitude estimation approach for a uniform motion and slowly rotating noncooperative spacecraft. It is assumed that the uniform motion and slowly rotating noncooperative chief spacecraft is in failure or out of control and there is no a priori rotation rate information. We utilize a very fast binary descriptor based on binary robust independent elementary features (BRIEF to obtain the features of the target, which are rotational invariance and resistance to noise. And then, we propose a novel combination of single candidate random sample consensus (RANSAC with extended Kalman filter (EKF that makes use of the available prior probabilistic information from the EKF in the RANSAC model hypothesis stage. The advantage of this combination obviously reduces the sample size to only one, which results in large computational savings without the loss of accuracy. Experimental results from real image sequence of a real model target show that the relative angular error is about 3.5% and the mean angular velocity error is about 0.1 deg/s.

The phenomenological version of modified Newtonian dynamics from the relativity principle of motion

International Nuclear Information System (INIS)

Giné, Jaume

2012-01-01

In this paper, we show that it is possible to deduce the first phenomenological version of modified Newtonian dynamics (MOND) proposed by Milgrom from the relativity principle of motion in connection with the observed accelerated expansion of the universe. A new form of μ(x) in the Milgrom formula for Newton's second law is obtained. Moreover, we establish the relation between MOND and the deceleration parameter. (paper)

Research and development of a control system for multi axis cooperative motion based on PMAC

Science.gov (United States)

Guo, Xiao-xiao; Dong, Deng-feng; Zhou, Wei-hu

2017-10-01

Based on Programmable Multi-axes Controller (PMAC), a design of a multi axis motion control system for the simulator of spatial targets' dynamic optical properties is proposed. According to analysis the properties of spatial targets' simulator motion control system, using IPC as the main control layer, TurboPMAC2 as the control layer to meet coordinated motion control, data acquisition and analog output. A simulator using 5 servomotors which is connected with speed reducers to drive the output axis was implemented to simulate the motion of both the sun and the space target. Based on PMAC using PID and a notch filter algorithm, negative feedback, the speed and acceleration feed forward algorithm to satisfy the axis' requirements of the good stability and high precision at low speeds. In the actual system, it shows that the velocity precision is higher than 0.04 s ° and the precision of repetitive positioning is better than 0.006° when each axis is at a low-speed. Besides, the system achieves the control function of multi axis coordinated motion. The design provides an important technical support for detecting spatial targets, also promoting the theoretical research.

Method of normal coordinates in the formulation of a system with dissipation: The harmonic oscillator

International Nuclear Information System (INIS)

Mshelia, E.D.

1994-07-01

The method of normal coordinates of the theory of vibrations is used in decoupling the motion of n oscillators (1 ≤ n ≤4) representing intrinsic degrees of freedom coupled to collective motion in a quantum mechanical model that allows the determination of the probability for energy transfer from collective to intrinsic excitations in a dissipative system. (author). 21 refs

Kinematics and Dynamics of Motion Control Based on Acceleration Control

Science.gov (United States)

Ohishi, Kiyoshi; Ohba, Yuzuru; Katsura, Seiichiro

The first IEEE International Workshop on Advanced Motion Control was held in 1990 pointed out the importance of physical interpretation of motion control. The software servoing technology is now common in machine tools, robotics, and mechatronics. It has been intensively developed for the numerical control (NC) machines. Recently, motion control in unknown environment will be more and more important. Conventional motion control is not always suitable due to the lack of adaptive capability to the environment. A more sophisticated ability in motion control is necessary for compliant contact with environment. Acceleration control is the key technology of motion control in unknown environment. The acceleration control can make a motion system to be a zero control stiffness system without losing the robustness. Furthermore, a realization of multi-degree-of-freedom motion is necessary for future human assistance. A human assistant motion will require various control stiffness corresponding to the task. The review paper focuses on the modal coordinate system to integrate the various control stiffness in the virtual axes. A bilateral teleoperation is a good candidate to consider the future human assistant motion and integration of decentralized systems. Thus the paper reviews and discusses the bilateral teleoperation from the control stiffness and the modal control design points of view.

Local Gaussian approximation in the generator coordinate method

International Nuclear Information System (INIS)

Onishi, Naoki; Une, Tsutomu.

1975-01-01

A transformation from a non-orthogonal representation to an orthogonal representation of wave functions is studied in the generator coordinate method. A differential equation can be obtained by the transformation for a case that the eigenvalue equation of the overlap kernel is solvable. By assuming local Gaussian overlap, we derive a Schroedinger-type equation for the collective motion from the Hill-Wheeler integral equation. (auth.)

Local Gaussian approximation in the generator coordinate method

Energy Technology Data Exchange (ETDEWEB)

Onishi, N [Tokyo Univ. (Japan). Coll. of General Education; Une, Tsutomu

1975-02-01

A transformation from a non-orthogonal representation to an orthogonal representation of wave functions is studied in the generator coordinate method. A differential equation can be obtained by the transformation for a case that the eigenvalue equation of the overlap kernel is solvable. By assuming local Gaussian overlap, we derive a Schroedinger-type equation for the collective motion from the Hill-Wheeler integral equation.

Zero-point motion in the bag description of the nucleon

International Nuclear Information System (INIS)

Brown, G.E.; Durso, J.W.; Johnson, M.B.

1983-01-01

In the bag model, confinement of quarks is accomplished by introduction of a boundary condition at some definite radius R, where the energy of the total system is a minimum. This minimum is, however, relatively shallow and energies for substantially different bag radii are not much larger than this minimum value. This indicates that the zero-point motion of the bag surface may be important. In this paper, quantization of the bag surface motion is carried out in a somewhat ad hoc fashion, modelled after the generator coordinate theory in nuclear physics. This procedure unifies a number of ideas previously in the literature; it stresses the anharmonicity of the collective motion. As in earlier treatments, the Roper resonance emerges as a breathing-mode type of excitation of the nucleon. The one- and two-pion decays of the Roper resonance are calculated and the widths are found to fall short of the empirical ones. It is pointed out, however, that decays involving intermediate states containing virtual rho-mesons will enhance the widths. Pion-nucleon scattering in the P 11 channel is constructed in our model and found to agree roughly with experiment. A crucial term in the driving force involves the pion coupling to the nucleon through a virtual rho-meson. With introduction of zero-point motion of the bag surface, the motion of 'bag radius' becomes dependent on precisely which moment of the radius is measured. Our development gives a model for cutting off smoothly the pion-exchange term in the nucleon-nucleon interaction. (orig.)

NMR with generalized dynamics of spin and spatial coordinates

International Nuclear Information System (INIS)

Lee, Chang Jae.

1987-11-01

This work is concerned with theoretical and experimental aspects of the generalized dynamics of nuclear spin and spatial coordinates under magnetic-field pulses and mechanical motions. The main text begins with an introduction to the concept of ''fictitious'' interactions. A systematic method for constructing fictitious spin-1/2 operators is given. The interaction of spins with a quantized-field is described. The concept of the fictitious interactions under the irradiation of multiple pulses is utilized to design sequences for selectively averaging linear and bilinear operators. Relations between the low-field sequences and high-field iterative schemes are clarified. These relations and the transformation properties of the spin operators are exploited to develop schemes for heteronuclear decoupling of multi-level systems. The resulting schemes are evaluated for heteronuclear decoupling of a dilute spin-1/2 from a spin-1 in liquid crystal samples and from a homonuclear spin-1/2 pair in liquids. A relation between the spin and the spatial variables is discussed. The transformation properties of the spin operators are applied to spatial coordinates and utilized to develop methods for removing the orientational dependence responsible for line broadening in a powder sample. Elimination of the second order quadrupole effects, as well as the first order anisotropies is discussed. It is shown that various sources of line broadening can effectively be eliminated by spinning and/or hopping the sample about judiciously chosen axes along with appropriate radio-frequency pulse sequences

Empirical ground-motion relations for subduction-zone earthquakes and their application to Cascadia and other regions

Science.gov (United States)

Atkinson, G.M.; Boore, D.M.

2003-01-01

Ground-motion relations for earthquakes that occur in subduction zones are an important input to seismic-hazard analyses in many parts of the world. In the Cascadia region (Washington, Oregon, northern California, and British Columbia), for example, there is a significant hazard from megathrust earthquakes along the subduction interface and from large events within the subducting slab. These hazards are in addition to the hazard from shallow earthquakes in the overlying crust. We have compiled a response spectra database from thousands of strong-motion recordings from events of moment magnitude (M) 5-8.3 occurring in subduction zones around the world, including both interface and in-slab events. The 2001 M 6.8 Nisqually and 1999 M 5.9 Satsop earthquakes are included in the database, as are many records from subduction zones in Japan (Kyoshin-Net data), Mexico (Guerrero data), and Central America. The size of the database is four times larger than that available for previous empirical regressions to determine ground-motion relations for subduction-zone earthquakes. The large dataset enables improved determination of attenuation parameters and magnitude scaling, for both interface and in-slab events. Soil response parameters are also better determined by the data. We use the database to develop global ground-motion relations for interface and in-slab earthquakes, using a maximum likelihood regression method. We analyze regional variability of ground-motion amplitudes across the global database and find that there are significant regional differences. In particular, amplitudes in Cascadia differ by more than a factor of 2 from those in Japan for the same magnitude, distance, event type, and National Earthquake Hazards Reduction Program (NEHRP) soil class. This is believed to be due to regional differences in the depth of the soil profile, which are not captured by the NEHRP site classification scheme. Regional correction factors to account for these differences are

Relating lateralization of eye use to body motion in the avoidance behavior of the chameleon (Chamaeleo chameleon).

Science.gov (United States)

Lustig, Avichai; Ketter-Katz, Hadas; Katzir, Gadi

2013-01-01

Lateralization is mostly analyzed for single traits, but seldom for two or more traits while performing a given task (e.g. object manipulation). We examined lateralization in eye use and in body motion that co-occur during avoidance behaviour of the common chameleon, Chamaeleo chameleon. A chameleon facing a moving threat smoothly repositions its body on the side of its perch distal to the threat, to minimize its visual exposure. We previously demonstrated that during the response (i) eye use and body motion were, each, lateralized at the tested group level (N = 26), (ii) in body motion, we observed two similar-sized sub-groups, one exhibiting a greater reduction in body exposure to threat approaching from the left and one--to threat approaching from the right (left- and right-biased subgroups), (iii) the left-biased sub-group exhibited weak lateralization of body exposure under binocular threat viewing and none under monocular viewing while the right-biased sub-group exhibited strong lateralization under both monocular and binocular threat viewing. In avoidance, how is eye use related to body motion at the entire group and at the sub-group levels? We demonstrate that (i) in the left-biased sub-group, eye use is not lateralized, (ii) in the right-biased sub-group, eye use is lateralized under binocular, but not monocular viewing of the threat, (iii) the dominance of the right-biased sub-group determines the lateralization of the entire group tested. We conclude that in chameleons, patterns of lateralization of visual function and body motion are inter-related at a subtle level. Presently, the patterns cannot be compared with humans' or related to the unique visual system of chameleons, with highly independent eye movements, complete optic nerve decussation and relatively few inter-hemispheric commissures. We present a model to explain the possible inter-hemispheric differences in dominance in chameleons' visual control of body motion during avoidance.

Relating lateralization of eye use to body motion in the avoidance behavior of the chameleon (Chamaeleo chameleon.

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Avichai Lustig

Full Text Available Lateralization is mostly analyzed for single traits, but seldom for two or more traits while performing a given task (e.g. object manipulation. We examined lateralization in eye use and in body motion that co-occur during avoidance behaviour of the common chameleon, Chamaeleo chameleon. A chameleon facing a moving threat smoothly repositions its body on the side of its perch distal to the threat, to minimize its visual exposure. We previously demonstrated that during the response (i eye use and body motion were, each, lateralized at the tested group level (N = 26, (ii in body motion, we observed two similar-sized sub-groups, one exhibiting a greater reduction in body exposure to threat approaching from the left and one--to threat approaching from the right (left- and right-biased subgroups, (iii the left-biased sub-group exhibited weak lateralization of body exposure under binocular threat viewing and none under monocular viewing while the right-biased sub-group exhibited strong lateralization under both monocular and binocular threat viewing. In avoidance, how is eye use related to body motion at the entire group and at the sub-group levels? We demonstrate that (i in the left-biased sub-group, eye use is not lateralized, (ii in the right-biased sub-group, eye use is lateralized under binocular, but not monocular viewing of the threat, (iii the dominance of the right-biased sub-group determines the lateralization of the entire group tested. We conclude that in chameleons, patterns of lateralization of visual function and body motion are inter-related at a subtle level. Presently, the patterns cannot be compared with humans' or related to the unique visual system of chameleons, with highly independent eye movements, complete optic nerve decussation and relatively few inter-hemispheric commissures. We present a model to explain the possible inter-hemispheric differences in dominance in chameleons' visual control of body motion during avoidance.

The instantaneous linear motion information measurement method based on inertial sensors for ships

Science.gov (United States)

Yang, Xu; Huang, Jing; Gao, Chen; Quan, Wei; Li, Ming; Zhang, Yanshun

2018-05-01

Ship instantaneous line motion information is the important foundation for ship control, which needs to be measured accurately. For this purpose, an instantaneous line motion measurement method based on inertial sensors is put forward for ships. By introducing a half-fixed coordinate system to realize the separation between instantaneous line motion and ship master movement, the instantaneous line motion acceleration of ships can be obtained with higher accuracy. Then, the digital high-pass filter is applied to suppress the velocity error caused by the low frequency signal such as schuler period. Finally, the instantaneous linear motion displacement of ships can be measured accurately. Simulation experimental results show that the method is reliable and effective, and can realize the precise measurement of velocity and displacement of instantaneous line motion for ships.

Special relativity and superluminal motions: a discussion of some recent experiments

Energy Technology Data Exchange (ETDEWEB)

Recami, E. [Istituto Nazionale di Fisica Nucleare, Milan (Italy)]|[Bergamo Univ., Bergamo (Italy). Fac. di Ingegneria]|[State Univ. of Campinas, Campinas (Brazil); Fontana, F. [Pirelli Cavi, Milan (Italy). R and D sector; Garavaglia, R. [Milan Univ., Milan (Italy). Dipt. di Scienze dell' Informazione

2000-03-01

Some experiments, performed at Berkeley, Cologne, Florence, Vienna, Orsay and Rennes led to the claim that something seems to travel with a group velocity larger than the speed c of light in vacuum. Various other experimental results seem to point in the same direction. For instance, localized wavelet-type solutions of Maxwell equations have been found, both theoretically and experimentally, that travel with superluminal speed. Even mounic and electronic neutrinos - it has been proposed - might be tachyons, since their square mass appears to be negative. With regard to the first mentioned experiments, it was very recently claimed by Guenter Nimtz that those results with evanescent waves or tunnelling photons - implying superluminal signal and impulse transmission - violate Einstein causality. This note, on the contrary, discusses that all such results do not place relativistic causality in jeopardy, even if they refer to actual tachyonic motions. In fact, special relativity can cope even with also the known paradoxes , devised for faster than light motion, even if this is not widely recognized. Here the paper shows, in detail and rigorously, how to solve the oldest casual paradox. originally proposed by Tolman, which is the kernel of many further tachyon paradoxes. The key to the solution is a careful application of tachyon mechanics, as it unambiguously follows from special relativity.

Special relativity and superluminal motions: a discussion of some recent experiments

International Nuclear Information System (INIS)

Recami, E.; Fontana, F.; Garavaglia, R.

2000-03-01

Some experiments, performed at Berkeley, Cologne, Florence, Vienna, Orsay and Rennes led to the claim that something seems to travel with a group velocity larger than the speed c of light in vacuum. Various other experimental results seem to point in the same direction. For instance, localized wavelet-type solutions of Maxwell equations have been found, both theoretically and experimentally, that travel with superluminal speed. Even muonic and electronic neutrinos - it has been proposed - might be tachyons, since their square mass appears to be negative. With regard to the first mentioned experiments, it was very recently claimed by Guenter Nimtz that those results with evanescent waves or tunnelling photons - implying superluminal signal and impulse transmission - violate Einstein causality. This note, on the contrary, discusses that all such results do not place relativistic causality in jeopardy, even if they refer to actual tachyonic motions. In fact, special relativity can cope even with also the known paradoxes , devised for faster than light motion, even if this is not widely recognized. Here the paper shows, in detail and rigorously, how to solve the oldest casual paradox. originally proposed by Tolman, which is the kernel of many further tachyon paradoxes. The key to the solution is a careful application of tachyon mechanics, as it unambiguously follows from special relativity

A Field Study of Performance Among Embarked Infantry Personnel Exposed to Waterborne Motion

Science.gov (United States)

2012-09-01

motion sickness. However, the symptoms associated with these sicknesses may also arise in the absence of motion. Cinema sickness and simulator... identical courses were constructed to facilitate the timely completion of 35 the physical coordination course. Participants with an odd identification...nearly identical to the layout at Pelican Point. Figure 9 shows the detailed course layout superimposed over an aerial view of Red Beach

Distinct interjoint coordination during fast alternate keystrokes in pianists with superior skill

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Shinichi eFuruya

2011-05-01

Full Text Available Musical performance requires motor skills to coordinate the movements of multiple joints in the hand and arm over a wide range of tempi. However, it is unclear whether the coordination of movement across joints would differ for musicians with different skill levels and how inter-joint coordination would vary in relation to music tempo. The present study addresses these issues by examining the kinematics and muscular activity of the hand and arm movements of professional and amateur pianists who strike two keys alternately with the thumb and little finger at various tempi. The professionals produced a smaller flexion velocity at the thumb and little finger and greater elbow pronation and supination velocity than did the amateurs. The experts also showed smaller extension angles at the metacarpo-phalangeal joint of the index and middle fingers, which were not being used to strike the keys. Furthermore, muscular activity in the extrinsic finger muscles was smaller for the experts than for the amateurs. These findings indicate that pianists with superior skill reduce the finger muscle load during keystrokes by taking advantage of differences in proximal joint motion and hand postural configuration. With an increase in tempo, the experts showed larger and smaller increases in elbow velocity and finger muscle co-activation, respectively, compared to the amateurs, highlighting skill-level-dependent differences in movement strategies for tempo adjustment. Finally, when striking as fast as possible, individual differences in the striking tempo among players were explained by their elbow velocities but not by their digit velocities. These findings suggest that pianists who are capable of faster keystrokes benefit more from proximal joint motion than do pianists who are not capable of faster keystrokes. The distinct movement strategy for tempo adjustment in pianists with superior skill would therefore ensure a wider range of musical expression.

Altered Coupling between Motion-Related Activation and Resting-State Brain Activity in the Ipsilesional Sensorimotor Cortex after Cerebral Stroke

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Jianping Hu

2017-07-01

Full Text Available Functional connectivity maps using resting-state functional magnetic resonance imaging (rs-fMRI can closely resemble task fMRI activation patterns, suggesting that resting-state brain activity may predict task-evoked activation or behavioral performance. However, this conclusion was mostly drawn upon a healthy population. It remains unclear whether the predictive ability of resting-state brain activity for task-evoked activation would change under different pathological conditions. This study investigated dynamic changes of coupling between patterns of resting-state functional connectivity (RSFC and motion-related activation in different stages of cerebral stroke. Twenty stroke patients with hand motor function impairment were involved. rs-fMRI and hand motion-related fMRI data were acquired in the acute, subacute, and early chronic stages of cerebral stroke on a 3-T magnetic resonance (MR scanner. Sixteen healthy participants were enrolled as controls. For each subject, an activation map of the affected hand was first created using general linear model analysis on task fMRI data, and then an RSFC map was determined by seeding at the peak region of hand motion activation during the intact hand task. We then measured the extent of coupling between the RSFC maps and motion-related activation maps. Dynamic changes of the coupling between the two fMRI maps were estimated using one-way repeated measures analysis of variance across the three stages. Moreover, imaging parameters were correlated with motor performances. Data analysis showed that there were different coupling patterns between motion-related activation and RSFC maps associating with the affected motor regions during the acute, subacute, and early chronic stages of stroke. Coupling strengths increased as the recovery from stroke progressed. Coupling strengths were correlated with hand motion performance in the acute stage, while coupling recovery was negatively correlated with the recovery

Orientation in space - one of constituents of dancings motions of deaf children 6-10 years old.

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Statiev S.I.

2011-12-01

Full Text Available The indexes of development of orientation in space of deaf children of midchildhood are considered. 258 children took part in experiment (from them 100 are children without pathology of auditory to the analyzer. The constituents of dancings motions of children are considered. The necessity of perfection of specific co-ordinating capabilities is marked for children. Possibilities are rotined in relation to the arbitrary weakening of muscles, vestibular firmness. It is well-proven that indexes of development of orientation in space of deaf children considerably less indexes of children without violation of auditory to the analyzer. It is set that the basic constituents of dancings motions are instrumental in the improvement of parameters of orientation of children in space.

MOTION PLANNING OF MULTIPLE MOBILE ROBOTS COOPERATIVELY TRANSPORTING A COMMON OBJECT

Institute of Scientific and Technical Information of China (English)

无

2000-01-01

Many applications above the capability of a single robot need the cooperation of multiple mobile robots, but effective cooperation is hard to achieve. In this paper, a master-slave method is proposed to control the motions of multiple mobile robots that cooperatively transport a common object from a start point to a goal point. A noholonomic kinematic model to constrain the motions of multiple mobile robots is built in order to achieve cooperative motions of them, and a "Dynamic Coordinator" strategy is used to deal with the collision-avoidance of the master robot and slave robot individually. Simulation results show the robustness and effectiveness of the method.

The distribution of cerebral activity related to visuomotor coordination indicating perceptual and executional specialization

NARCIS (Netherlands)

de Jong, BM; Frackowiak, RSJ; Willemsen, ATM; Paans, AMJ

The distribution of increased regional cerebral blood flow (rCBF) related to visuomotor coordination was studied by means of positron emission tomography (PET) in normal subjects. An experimental condition, in which a vertically presented zigzag figure had to be copied in a horizontal orientation,

Focusing narrowly or broadly attention when judging categorical and coordinate spatial relations: a MEG study.

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Raffaella Franciotti

Full Text Available We measured activity in the dorsal system of the human cortex with magnetoencephalography (MEG during a matching-to-sample plus cueing paradigm, where participants judged the occurrence of changes in either categorical or coordinate spatial relations (e.g., exchanges of left versus right positions or changes in the relative distances between images of pairs of animals. The attention window was primed in each trial to be either small or large by using cues that immediately preceded the matching image. In this manner, we could assess the modulatory effects of the scope of attention on the activity of the dorsal system of the human cortex during spatial relations processing. The MEG measurements revealed that large spatial cues yielded greater activations and longer peak latencies in the right inferior parietal lobe for coordinate trials, whereas small cues yielded greater activations and longer peak latencies in the left inferior parietal lobe for categorical trials. The activity in the superior parietal lobe, middle frontal gyrus, and visual cortex, was also modulated by the size of the spatial cues and by the type of spatial relation change. The present results support the theory that the lateralization of each kind of spatial processing hinges on differences in the sizes of regions of space attended to by the two hemispheres. In addition, the present findings are inconsistent with the idea of a right-hemispheric dominance for all kinds of challenging spatial tasks, since response times and accuracy rates showed that the categorical spatial relation task was more difficult than the coordinate task and the cortical activations were overall greater in the left hemisphere than in the right hemisphere.

The Relative Importance of Spatial Versus Temporal Structure in the Perception of Biological Motion: An Event-Related Potential Study

Science.gov (United States)

Hirai, Masahiro; Hiraki, Kazuo

2006-01-01

We investigated how the spatiotemporal structure of animations of biological motion (BM) affects brain activity. We measured event-related potentials (ERPs) during the perception of BM under four conditions: normal spatial and temporal structure; scrambled spatial and normal temporal structure; normal spatial and scrambled temporal structure; and…

The roles of categorical and coordinate spatial relations in recognizing buildings.

Science.gov (United States)

Palermo, Liana; Piccardi, Laura; Nori, Raffaella; Giusberti, Fiorella; Guariglia, Cecilia

2012-11-01

Categorical spatial information is considered more useful for recognizing objects, and coordinate spatial information for guiding actions--for example, during navigation or grasping. In contrast with this assumption, we hypothesized that buildings, unlike other categories of objects, require both categorical and coordinate spatial information in order to be recognized. This hypothesis arose from evidence that right-brain-damaged patients have deficits in both coordinate judgments and recognition of buildings and from the fact that buildings are very useful for guiding navigation in urban environments. To test this hypothesis, we assessed 210 healthy college students while they performed four different tasks that required categorical and coordinate judgments and the recognition of common objects and buildings. Our results showed that both categorical and coordinate spatial representations are necessary to recognize a building, whereas only categorical representations are necessary to recognize an object. We discuss our data in view of a recent neural framework for visuospatial processing, suggesting that recognizing buildings may specifically activate the parieto-medial-temporal pathway.

'Motion frozen' quantification and display of myocardial perfusion gated SPECT

International Nuclear Information System (INIS)

Slomka, P.J.; Hurwitz, G.A.; Baddredine, M.; Baranowski, J.; Aladl, U.E.

2002-01-01

Aim: Gated SPECT imaging incorporates both functional and perfusion information of the left ventricle (LV). However perfusion data is confounded by the effect of ventricular motion. Most existing quantification paradigms simply add all gated frames and then proceed to extract the perfusion information from static images, discarding the effects of cardiac motion. In an attempt to improve the reliability and accuracy of cardiac SPECT quantification we propose to eliminate the LV motion prior to the perfusion quantification via automated image warping algorithm. Methods: A pilot series of 14 male and 11 female gated stress SPECT images acquired with 8 time bins have been co-registered to the coordinates of the 3D normal templates. Subsequently the LV endo and epi-cardial 3D points (300-500) were identified on end-systolic (ES) and end-diastolic (ED) frames, defining the ES-ED motion vectors. The nonlinear image warping algorithm (thin-plate-spline) was then applied to warp end-systolic frame was onto the end-diastolic frames using the corresponding ES-ED motion vectors. The remaining 6 intermediate frames were also transformed to the ED coordinates using fractions of the motion vectors. Such warped images were then summed to provide the LV perfusion image in the ED phase but with counts from the full cycle. Results: The identification of the ED/ES corresponding points was successful in all cases. The corrected displacement between ED and ES images was up to 25 mm. The summed images had the appearance of the ED frames but have been much less noisy since all the counts have been used. The spatial resolution of such images appeared higher than that of summed gated images, especially in the female scans. These 'motion frozen' images could be displayed and quantified as regular non-gated tomograms including polar map paradigm. Conclusions: This image processing technique may improve the effective image resolution of summed gated myocardial perfusion images used for

Experimenting relations between artists and scientists : the appropriation of motion sensors by dancers

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Fabienne MARTIN-JUCHAT

2013-07-01

Full Text Available We want to show here how recent innovations called Motion Capture, still being tested in laboratory on their potential uses, invite us to change our way to relate to the “technique”. We don’t want to question what the technique does to the social, nor what the social structures does to the technique, but we want to highlight the shifting principles that define interactions between technologies and humans. We therefore underline how using these motion sensors gives birth to different human modes of being present, co-present, or in a sensory and thymic interaction with technology. This article is based on experimental use tests, convoking both artists and engineers, questioning differently the relationship between technology, human and the interaction order. Our result is to question how using and being with these motion sensors, as a dancer, displace epistemological oppositions such as person/machine. It finally sheds light on how some others classical models can move, especially the semiotic decomposition of interaction processes and status.

Parametrized post-Newtonian theory of reference frames, multipolar expansions and equations of motion in the N-body problem

International Nuclear Information System (INIS)

Kopeikin, Sergei; Vlasov, Igor

2004-01-01

Post-Newtonian relativistic theory of astronomical reference frames based on Einstein's general theory of relativity was adopted by General Assembly of the International Astronomical Union in 2000. This theory is extended in the present paper by taking into account all relativistic effects caused by the presumable existence of a scalar field and parametrized by two parameters, β and γ, of the parametrized post-Newtonian (PPN) formalism. We use a general class of the scalar-tensor (Brans-Dicke type) theories of gravitation to work out PPN concepts of global and local reference frames for an astronomical N-body system. The global reference frame is a standard PPN coordinate system. A local reference frame is constructed in the vicinity of a weakly self-gravitating body (a sub-system of the bodies) that is a member of the astronomical N-body system. Such local inertial frame is required for unambiguous derivation of the equations of motion of the body in the field of other members of the N-body system and for construction of adequate algorithms for data analysis of various gravitational experiments conducted in ground-based laboratories and/or on board of spacecrafts in the solar system.We assume that the bodies comprising the N-body system have weak gravitational field and move slowly. At the same time we do not impose any specific limitations on the distribution of density, velocity and the equation of state of the body's matter. Scalar-tensor equations of the gravitational field are solved by making use of the post-Newtonian approximations so that the metric tensor and the scalar field are obtained as functions of the global and local coordinates. A correspondence between the local and global coordinate frames is found by making use of asymptotic expansion matching technique. This technique allows us to find a class of the post-Newtonian coordinate transformations between the frames as well as equations of translational motion of the origin of the local frame

Collective coordinates and an accompanying metric force in structural isomerization dynamics of molecules

International Nuclear Information System (INIS)

Yanao, Tomohiro; Takatsuka, Kazuo

2003-01-01

Structural isomerization dynamics of three- and four-atom clusters of vanishing total angular momentum is studied in terms of internal coordinates of n-body systems on the basis of a gauge theory. The so-called principal-axis hyperspherical coordinates are employed effectively as collective variables for the study of isomerization reactions. It turns out that the non-Euclidean metric on the internal space gives rise to a force, which works in response to internal motions called the democratic (kinematic) rotations in the internal space. This metric force generally tends to induce an asymmetry in mass balance of a system, and is coupled with the usual potential force to give rise to trapped motions in the vicinity of the transition states of the cluster. This observation provides a different perspective for the so-called recrossing problem in chemical reaction dynamics

Near-Horizon Geodesics for Astrophysical and Idealised Black Holes: Coordinate Velocity and Coordinate Acceleration

Directory of Open Access Journals (Sweden)

Petarpa Boonserm

2018-05-01

Full Text Available Geodesics (by definition have an intrinsic 4-acceleration zero. However, when expressed in terms of coordinates, the coordinate acceleration d 2 x i / d t 2 can very easily be non-zero, and the coordinate velocity d x i / d t can behave unexpectedly. The situation becomes extremely delicate in the near-horizon limit—for both astrophysical and idealised black holes—where an inappropriate choice of coordinates can quite easily lead to significant confusion. We shall carefully explore the relative merits of horizon-penetrating versus horizon-non-penetrating coordinates, arguing that in the near-horizon limit the coordinate acceleration d 2 x i / d t 2 is best interpreted in terms of horizon-penetrating coordinates.

A Simple Time Domain Collocation Method to Precisely Search for the Periodic Orbits of Satellite Relative Motion

Directory of Open Access Journals (Sweden)

Xiaokui Yue

2014-01-01

Full Text Available A numerical approach for obtaining periodic orbits of satellite relative motion is proposed, based on using the time domain collocation (TDC method to search for the periodic solutions of an exact J2 nonlinear relative model. The initial conditions for periodic relative orbits of the Clohessy-Wiltshire (C-W equations or Tschauner-Hempel (T-H equations can be refined with this approach to generate nearly bounded orbits. With these orbits, a method based on the least-squares principle is then proposed to generate projected closed orbit (PCO, which is a reference for the relative motion control. Numerical simulations reveal that the presented TDC searching scheme is effective and simple, and the projected closed orbit is very fuel saving.

Coordination chemistry of technetium as related to nuclear medicine

International Nuclear Information System (INIS)

Srivastava, S.C.; Richards, P.

1982-01-01

Significant advances have been made in the area of technetium coordination chemistry during the last five years. The main driving force behind this recent surge of interest in the field has been due to the practical application of technetium-99m in the rapidly growing speciality of nuclear medicine. Technetium-99 is one of the products of nuclear fission reactions, but it was the development of the molybdenum-99-technetium-99m generator about two decades ago that provided the basis for the development of radiopharmaceuticals routinely used in modern diagnostic applications. The chemistry of this element has proven to be quite rich owing to its multiple oxidation states and variable geometry. This can be attributed to its position in the middle of the periodic table. Diagnostic radiopharmaceuticals comprise predominantly III, IV and V oxidation states of Tc and involve a variety of coordination complexes. Even though the chemistry of Tc has been slow to evolve, recent synthetic advances have provided a more scientific basis for the study of a number of compounds with diverse coordination geometries and structures. Ligands with oxygen, nitrogen and sulfur donor atoms have been utilized to elucidate various aspects of the coordination chemistry of Tc. Single crystal X-ray structural analysis has been extensively used to characterize Tc complexes and thus construct a firm foundation for the study of synthetic and mechanistic aspects of the chemistry of this element. (author)

Motions on a rotating planet

Science.gov (United States)

Schröer, H.

In chapter 1 we want to describe the motion of a falling body on a rotating planet. The planet rotates with an arbitrary changable angular velocity and has a translational acceleration. We obtain 3 differential equations. For the general gravitational field an exact solution is possible, when the differential equation system is explicit solvable. Then we consider the case, if the angular velocity and the translational acceleration is constant. With a special transformation we get 3 partial differential equations of first order. Instead of a planet sphere we can choose a general body of rotation. Even general bodies are possible. Chapter 2 contains the motion in a local coordinate system on planet's surface. We have an inhomogeneous linear differential equation of first order. If the angular velocity is constant, we get a system with constant coefficients. There is an english and a german edition.

Estimation of object motion parameters from noisy images.

Science.gov (United States)

Broida, T J; Chellappa, R

1986-01-01

An approach is presented for the estimation of object motion parameters based on a sequence of noisy images. The problem considered is that of a rigid body undergoing unknown rotational and translational motion. The measurement data consists of a sequence of noisy image coordinates of two or more object correspondence points. By modeling the object dynamics as a function of time, estimates of the model parameters (including motion parameters) can be extracted from the data using recursive and/or batch techniques. This permits a desired degree of smoothing to be achieved through the use of an arbitrarily large number of images. Some assumptions regarding object structure are presently made. Results are presented for a recursive estimation procedure: the case considered here is that of a sequence of one dimensional images of a two dimensional object. Thus, the object moves in one transverse dimension, and in depth, preserving the fundamental ambiguity of the central projection image model (loss of depth information). An iterated extended Kalman filter is used for the recursive solution. Noise levels of 5-10 percent of the object image size are used. Approximate Cramer-Rao lower bounds are derived for the model parameter estimates as a function of object trajectory and noise level. This approach may be of use in situations where it is difficult to resolve large numbers of object match points, but relatively long sequences of images (10 to 20 or more) are available.

Hierarchical Aligned Cluster Analysis for Temporal Clustering of Human Motion.

Science.gov (United States)

Zhou, Feng; De la Torre, Fernando; Hodgins, Jessica K

2013-03-01

Temporal segmentation of human motion into plausible motion primitives is central to understanding and building computational models of human motion. Several issues contribute to the challenge of discovering motion primitives: the exponential nature of all possible movement combinations, the variability in the temporal scale of human actions, and the complexity of representing articulated motion. We pose the problem of learning motion primitives as one of temporal clustering, and derive an unsupervised hierarchical bottom-up framework called hierarchical aligned cluster analysis (HACA). HACA finds a partition of a given multidimensional time series into m disjoint segments such that each segment belongs to one of k clusters. HACA combines kernel k-means with the generalized dynamic time alignment kernel to cluster time series data. Moreover, it provides a natural framework to find a low-dimensional embedding for time series. HACA is efficiently optimized with a coordinate descent strategy and dynamic programming. Experimental results on motion capture and video data demonstrate the effectiveness of HACA for segmenting complex motions and as a visualization tool. We also compare the performance of HACA to state-of-the-art algorithms for temporal clustering on data of a honey bee dance. The HACA code is available online.

Higher order coupling between rigid-body and elastic motion in flexible mechanisms

International Nuclear Information System (INIS)

Esat, I.I.; Ianakiev, A.

1995-01-01

The paper presents an investigation of the influence of the higher order coupling terms between the rigid-body and elastic motion into flexible mechanism dynamics. The configuration of the mechanical system is obtained by using the so called hybrid coordinates. The kinematic description of the mechanism was obtained using the D-H 4 x 4 transformation matrices. The elastic deformation of each point of the mechanism is described by the finite element modeling (FEM) type interpolation scheme. The dynamic model of the flexible mechanism consists due to the hybrid coordinates of two groups of differential equations. The first group describes the manipulator transport motion and the second group describes the vibration. In this paper the authors evaluated the contribution of the coupling terms between the two groups of differential equations and selected only those with high contribution

The accommodation of relative motion at depth on the San Andreas fault system in California

Science.gov (United States)

Prescott, W. H.; Nur, A.

1981-01-01

Plate motion below the seismogenic layer along the San Andreas fault system in California is assumed to form by aseismic slip along a deeper extension of the fault or may result from lateral distribution of deformation below the seismogenic layer. The shallow depth of California earthquakes, the depth of the coseismic slip during the 1906 San Francisco earthquake, and the presence of widely separated parallel faults indicate that relative motion is distributed below the seismogenic zone, occurring by inelastic flow rather than by aseismic slip on discrete fault planes.

Parkinson-Related Changes of Activation in Visuomotor Brain Regions during Perceived Forward Self-Motion

NARCIS (Netherlands)

van der Hoorn, Anouk; Renken, Remco J.; Leenders, Klaus L.; de Jong, Bauke M.

2014-01-01

Radial expanding optic flow is a visual consequence of forward locomotion. Presented on screen, it generates illusionary forward self-motion, pointing at a close vision-gait interrelation. As particularly parkinsonian gait is vulnerable to external stimuli, effects of optic flow on motor-related

Non-linear Response to a Type of Seismic Input Motion

International Nuclear Information System (INIS)

2011-06-01

This publication reports the results and findings of a coordinated research project on the safety significance of near-field earthquakes in the design of nuclear power plants. It describes the outcome of a benchmark exercise conducted by a number of institutions on the effects of low to moderate magnitude near-field earthquakes, comparing model analytical simulations with the results of a shaking test performed in France on a physical model of a conventional shear-wall structure. The results build the basis for proposals for possible evolution of engineering practices in order to realistically take into account the effects of near-field earthquakes. A CD is attached that contains the List of participants; Summary of the Research Coordination Meetings; Description of the CAMUS data; Description of the Japanese input motions: near-field earthquakes observed recently in Japan; Description of the output requested of the IAEA CRP participants; Summary of the participants' modelling; Results of Benchmark Step 1, 2 and 3; Scientific background on classification of seismic loads as primary or secondary; and Japanese practice on nonlinear seismic response analysis of safety related important structures.

From Cannibalism to Active Motion of Groups

Science.gov (United States)

Romanczuk, Pawel; Schimansky-Geier, Lutz

2008-03-01

The detailed mechanisms leading to collective dynamics in groups of animals and insect are still poorly understood. A recent study by Simpson et. al. suggests cannibalism as a driving mechanism for coordinated migration of mormon crickets [1]. Based on this result we propose a simple generic model of brownian particles interacting by asymmetric, non-conservative collisions accounting for cannibalistic behavior and the corresponding avoidance strategy. We discuss our model in one and two dimensions and show that a certain type of collisions drives the system out of equilibrium and leads to coordinated active motion of groups.[1] Stephen J. Simpson, Gregory A. Sword, Patrick D. Lorch and Iain D. Couzin: Cannibal crickets on a forced march for protein and salt, PNAS, 103:4152-4156, 2006

Structural motion engineering

CERN Document Server

Connor, Jerome

2014-01-01

This innovative volume provides a systematic treatment of the basic concepts and computational procedures for structural motion design and engineering for civil installations. The authors illustrate the application of motion control to a wide spectrum of buildings through many examples. Topics covered include optimal stiffness distributions for building-type structures, the role of damping in controlling motion, tuned mass dampers, base isolation systems, linear control, and nonlinear control. The book's primary objective is the satisfaction of motion-related design requirements, such as restrictions on displacement and acceleration. The book is ideal for practicing engineers and graduate students. This book also: ·         Broadens practitioners' understanding of structural motion control, the enabling technology for motion-based design ·         Provides readers the tools to satisfy requirements of modern, ultra-high strength materials that lack corresponding stiffness, where the motion re...

Constant of motion for a one-dimensional and nth-order autonomous system and its relation to the Lagrangian and Hamiltonian

International Nuclear Information System (INIS)

Lopez, G.

1993-12-01

A constant of motion is defined for a one-dimensional and nth-differenital-order autonomous svstem. A generalization of the Legendre transformation is given that allows one to obtain a relation among the constant of motion the Lagrangian, and the Hamiltonian. The approach is used to obtain the constant of motion associated with the nonrelativistic third-differential-order Abraham-Lorentz radiation damping equation

29 CFR 42.8 - Coordination plan.

Science.gov (United States)

2010-07-01

... 29 Labor 1 2010-07-01 2010-07-01 true Coordination plan. 42.8 Section 42.8 Labor Office of the Secretary of Labor COORDINATED ENFORCEMENT § 42.8 Coordination plan. (a) Based upon, among other things, the... coordination plan concerning farm labor-related responsibilities of the Department, including migrant housing...

Relative tracking control of constellation satellites considering inter-satellite link

Science.gov (United States)

Fakoor, M.; Amozegary, F.; Bakhtiari, M.; Daneshjou, K.

2017-11-01

In this article, two main issues related to the large-scale relative motion of satellites in the constellation are investigated to establish the Inter Satellite Link (ISL) which means the dynamic and control problems. In the section related to dynamic problems, a detailed and effective analytical solution is initially provided for the problem of satellite relative motion considering perturbations. The direct geometric method utilizing spherical coordinates is employed to achieve this solution. The evaluation of simulation shows that the solution obtained from the geometric method calculates the relative motion of the satellite with high accuracy. Thus, the proposed analytical solution will be applicable and effective. In the section related to control problems, the relative tracking control system between two satellites will be designed in order to establish a communication link between the satellites utilizing analytical solution for relative motion of satellites with respect to the reference trajectory. Sliding mode control approach is employed to develop the relative tracking control system for body to body and payload to payload tracking control. Efficiency of sliding mode control approach is compared with PID and LQR controllers. Two types of payload to payload tracking control considering with and without payload degree of freedom are designed and suitable one for practical ISL applications is introduced. Also, Fuzzy controller is utilized to eliminate the control input in the sliding mode controller.

Influence of tides in viscoelastic bodies of planet and satellite on the satellite's orbital motion

Science.gov (United States)

Emelyanov, N. V.

2018-06-01

The problem of influence of tidal friction in both planetary and satellite bodies upon satellite's orbital motion is considered. Using the differential equations in satellite's rectangular planetocentric coordinates, the differential equations describing the changes in semimajor axis and eccentricity are derived. The equations in rectangular coordinates were taken from earlier works on the problem. The calcultations carried out for a number of test examples prove that the averaged solutions of equations in coordinates and precise solutions of averaged equations in the Keplerian elements are identical. For the problem of tides raised on planet's body, it was found that, if satellite's mean motion n is equal to 11/18 Ω, where Ω is the planet's angular rotation rate, the orbital eccentricity does not change. This conclusion is in agreement with the results of other authors. It was also found that there is essential discrepancy between the equations in the elements obtained in this paper and analogous equations published by earlier researchers.

Thoraco-abdominal coordination and performance during uphill running at altitude.

Directory of Open Access Journals (Sweden)

Eva Bernardi

Full Text Available Running races on mountain trails at moderate-high altitude with large elevation changes throughout has become increasingly popular. During exercise at altitude, ventilatory demands increase due to the combined effects of exercise and hypoxia.To investigate the relationships between thoraco-abdominal coordination, ventilatory pattern, oxygen saturation (SpO2, and endurance performance in runners during high-intensity uphill exercise.Fifteen participants (13 males, mean age 42±9 yrs ran a "Vertical Kilometer," i.e., an uphill run involving a climb of approximately 1000 m with a slope greater than 30%. The athletes were equipped with a portable respiratory inductive plethysmography system, a finger pulse oximeter and a global positioning unit (GPS. The ventilatory pattern (ventilation (VE, tidal volume (VT, respiratory rate (RR, and VE/VT ratio, thoraco-abdominal coordination, which is represented by the phase angle (PhA, and SpO2 were evaluated at rest and during the run. Before and after the run, we assessed respiratory function, respiratory muscle strength and the occurrence of interstitial pulmonary edema by thoracic ultrasound.Two subjects were excluded from the respiratory inductive plethysmography analysis due to motion artifacts. A quadratic relationship between the slope and the PhA was observed (r = 0.995, p = 0.036. When the slope increased above 30%, the PhA increased, indicating a reduction in thoraco-abdominal coordination. The reduced thoraco-abdominal coordination was significantly related to reduced breathing efficiency (i.e., an increased VE/VT ratio; r = 0.961, p = 0.038 and SpO2 (r = -0.697, p<0.001. Lower SpO2 values were associated with lower speeds at 20%≥slope≤40% (r = 0.335, p<0.001 for horizontal and r = 0.36, p<0.001 for vertical. The reduced thoraco-abdominal coordination and consequent reduction in SpO2 were associated with interstitial pulmonary edema.Reductions in thoraco-abdominal coordination are associated

Effects of five hindfoot arthrodeses on foot and ankle motion: Measurements in cadaver specimens

Science.gov (United States)

Zhang, Kun; Chen, Yanxi; Qiang, Minfei; Hao, Yini

2016-01-01

Single, double, and triple hindfoot arthrodeses are used to correct hindfoot deformities and relieve chronic pain. However, joint fusion may lead to dysfunction in adjacent articular surfaces. We compared range of motion in adjacent joints before and after arthrodesis to determine the effects of each procedure on joint motion. The theory of moment of couple, bending moment and balanced loading was applied to each of 16 fresh cadaver feet to induce dorsiflexion, plantarflexion, internal rotation, external rotation, inversion, and eversion. Range of motion was measured with a 3-axis coordinate measuring machine in a control foot and in feet after subtalar, talonavicular, calcaneocuboid, double, or triple arthrodesis. All arthrodeses restricted mainly internal-external rotation and inversion-eversion. The restriction in a double arthrodesis was more than that in a single arthrodesis, but that in a calcaneocuboid arthrodesis was relatively low. After triple arthrodeses, the restriction on dorsiflexion and plantarflexion movements was substantial, and internal-external rotation and inversion-eversion were almost lost. Considering that different arthrodesis procedures cause complex, three-dimensional hindfoot motion reductions, we recommend talonavicular or calcaneocuboid arthrodesis for patients with well-preserved functions of plantarflexion/dorsiflexion before operation, subtalar or calcaneocuboid arthrodesis for patients with well-preserved abduction/adduction, and talonavicular arthrodesis for patients with well-preserved eversion/inversion. PMID:27752084

Geometric Relations for CYLEX Test Tube-Wall Motion

Science.gov (United States)

Hill, Larry

2015-06-01

The CYLinder EXpansion (CYLEX) test is a (precision, instrumented, high-purity annealed copper) pipe bomb. Its essential measured quantities are detonation speed and tube-wall motion. Its main purpose is to calibrate detonation product equations of state (EOS) by measuring how product fluid pushes metal. In its full complexity, CYLEX is an integral test, for which EOS calibration requires the entire system to be computationally modeled and compared to salient data. Stripped to its essence, CYLEX is a non-integral test for which one may perform the inverse problem, to infer the EOS directly from data. CYLEX analysis can be simplified by the fact that the test constituents achieve a steady traveling wave structure; this allows derivation of several useful geometric relationships regarding tube wall motion. The first such treatment was by G.I. Taylor. Although his analysis was limited to small wall deflection angles, he asserted that the results remain valid for arbitrary ones. I confirm this attribute and present additional useful relationships. In the past decade, CYLEX wall-motion instrumentation has migrated almost entirely from streak camera to PDV, yet discrepancies remain between the two methods. I further present geometric relationships that shed light on this issue. Work supported by the U.S. DOE.

Bayesian noise-reduction in Arabia/Somalia and Nubia/Arabia finite rotations since ˜20 Ma: Implications for Nubia/Somalia relative motion

Science.gov (United States)

Iaffaldano, Giampiero; Hawkins, Rhys; Sambridge, Malcolm

2014-04-01

Knowledge of Nubia/Somalia relative motion since the Early Neogene is of particular importance in the Earth Sciences, because it (i) impacts on inferences on African dynamic topography; and (ii) allows us to link plate kinematics within the Indian realm with those within the Atlantic basin. The contemporary Nubia/Somalia motion is well known from geodetic observations. Precise estimates of the past-3.2-Myr average motion are also available from paleo-magnetic observations. However, little is known of the Nubia/Somalia motion prior to ˜3.2 Ma, chiefly because the Southwest Indian Ridge spread slowly, posing a challenge to precisely identify magnetic lineations. This also makes the few observations available particularly prone to noise. Here we reconstruct Nubia/Somalia relative motions since ˜20 Ma from the alternative plate-circuit Nubia-Arabia-Somalia. We resort to trans-dimensional hierarchical Bayesian Inference, which has proved effective in reducing finite-rotation noise, to unravel the Arabia/Somalia and Arabia/Nubia motions. We combine the resulting kinematics to reconstruct the Nubia/Somalia relative motion since ˜20 Ma. We verify the validity of the approach by comparing our reconstruction with the available record for the past ˜3.2 Myr, obtained through Antarctica. Results indicate that prior to ˜11 Ma the total motion between Nubia and Somalia was faster than today. Furthermore, it featured a significant strike-slip component along the Nubia/Somalia boundary. It is only since ˜11 Ma that Nubia diverges away from Somalia at slower rates, comparable to the present-day one. Kinematic changes of some 20% might have occurred in the period leading to the present-day, but plate-motion steadiness is also warranted within the uncertainties.

Interjoint coordination of the lower extremities in short-track speed skating.

Science.gov (United States)

Khuyagbaatar, Batbayar; Purevsuren, Tserenchimed; Park, Won Man; Kim, Kyungsoo; Kim, Yoon Hyuk

2017-10-01

In short-track speed skating, the three-dimensional kinematics of the lower extremities during the whole skating cycle have not been studied. Kinematic parameters of the lower extremities during skating are presented as joint angles versus time. However, the angle-time presentation is not sufficient to describe the relationship between multi-joint movement patterns. Thus, angle-angle presentations were developed and used to describe interjoint coordination in sport activities. In this study, 15 professional male skaters' full body motion data were recorded using a wearable motion capture system during short-track speed skating. We investigated the three-dimensional kinematics of the lower extremities and then established the interjoint coordination between hip-knee and knee-ankle for both legs during the whole skating cycle. The results demonstrate the relationship between multi-joint movements during different phases of short-track speed skating. This study provides fundamentals of the movement mechanism of the lower extremities that can be integrated with physiotherapy to improve skating posture and prevent injuries from repetitive stress since physiological characteristics play an important role in skating performance.

On the motion od the Caribbean relative to South-America: New results from GPS geodesy 1999-2012

Science.gov (United States)

De La Rosa, R.; Marquez, J.; Bravo, M.; Madriz, Y.; Mencin, D.; Wesnousky, S. G.; Molnar, P. H.; Bilham, R.; Perez, O. J.

2013-05-01

Our previous (1994-2006) collaborative GPS studies in southern Caribbean and northern South-America (SA) show that along its southern boundary in north-central and northeastern Venezuela (Vzla) the Caribbean plate (CP) slips easterly at ~20 mm/a relative to SA, and that in northwestern South-America slip-partitioning takes place resulting in 12 mm/a of dextral motion across the Venezuelan Andes, ~6 mm/a of which occur along the main trace of the NE-trending Bocono fault, and the rest is taken up by SE-subduction of the CP beneath northwestern SA. A series of new velocity vectors obtained in the region from GPS geodesy in 1999-2012 and their corresponding elastic modelings shows that in north-central Vzla part (~3 mm/a) of the C-SA relative dextral shear is taken up by the east-trending continental La Victoria fault, which runs ~50 kms south of San Sebastian fault off-shore and is sub-parallel to it, the later taken up the rest of the motion. The velocity we find for Aruba Is (~20 mm/y due ~east) is consistent with the motion predicted by the Euler pole (61,9° N; 75,7 °W; ω = 0,229 °/Ma) we previously calculated to describe the C-SA relative plate motion. New velocity vectors obtained across the Venezuelan Andes are consistent with a modeled surface velocity due to 12 mm/a of dextral shear below a locking depth of 14 km on one or more vertical N50°E striking faults located within the 100-km wide Andean ranges. The Andes also show a horizontal convergence rate of 2 to 4 mm/a suggesting an uplift rate of ~1.7 mm/a if thrust motion takes place on shallowly dipping faults parallel to the Andes.

Necessary conditions for tumbling in the rotational motion

Science.gov (United States)

Carrera, Danny H. Z.; Weber, Hans I.

2012-11-01

The goal of this work is the investigation of the necessary conditions for the possible existence of tumbling in rotational motion of rigid bodies. In a stable spinning satellite, tumbling may occur by sufficient strong action of external impulses, when the conical movement characteristic of the stable attitude is de-characterized. For this purpose a methodology is chosen to simplify the study of rotational motions with great amplitude, for example free bodies in space, allowing an extension of the analysis to non-conservative systems. In the case of a satellite in space, the projection of the angular velocity along the principal axes of inertia must be known, defining completely the initial conditions of motion for stability investigations. In this paper, the coordinate systems are established according to the initial condition in order to allow a simple analytical work on the equations of motion. Also it will be proposed the definition of a parameter, calling it tumbling coefficient, to measure the intensity of the tumbling and the amplitude of the motion when crossing limits of stability in the concept of Lyapunov. Tumbling in the motion of bodies in space is not possible when this coefficient is positive. Magnus Triangle representation will be used to represent the geometry of the body, establishing regions of stability/instability for possible initial conditions of motion. In the study of nonconservative systems for an oblate body, one sufficient condition will be enough to assure damped motion, and this condition is checked for a motion damped by viscous torques. This paper seeks to highlight the physical understanding of the phenomena and the influence of various parameters that are important in the process.

Receptive fields for smooth pursuit eye movements and motion perception.

Science.gov (United States)

Debono, Kurt; Schütz, Alexander C; Spering, Miriam; Gegenfurtner, Karl R

2010-12-01

Humans use smooth pursuit eye movements to track moving objects of interest. In order to track an object accurately, motion signals from the target have to be integrated and segmented from motion signals in the visual context. Most studies on pursuit eye movements used small visual targets against a featureless background, disregarding the requirements of our natural visual environment. Here, we tested the ability of the pursuit and the perceptual system to integrate motion signals across larger areas of the visual field. Stimuli were random-dot kinematograms containing a horizontal motion signal, which was perturbed by a spatially localized, peripheral motion signal. Perturbations appeared in a gaze-contingent coordinate system and had a different direction than the main motion including a vertical component. We measured pursuit and perceptual direction discrimination decisions and found that both steady-state pursuit and perception were influenced most by perturbation angles close to that of the main motion signal and only in regions close to the center of gaze. The narrow direction bandwidth (26 angular degrees full width at half height) and small spatial extent (8 degrees of visual angle standard deviation) correspond closely to tuning parameters of neurons in the middle temporal area (MT). Copyright © 2010 Elsevier Ltd. All rights reserved.

Turning Symbolic: The representation of motion direction in working memory

Directory of Open Access Journals (Sweden)

Tal eSeidel Malkinson

2016-02-01

Full Text Available What happens to the representation of a moving stimulus when it is no longer present and its motion direction has to be maintained in working memory (WM? Is the initial, sensorial representation maintained during the delay period or is there another representation, at a higher level of abstraction? It is also feasible that multiple representations may co-exist in WM, manifesting different facets of sensory and more abstract features.To that end, we investigated the mnemonic representation of motion direction in a series of three psychophysical experiments, using a delayed motion-discrimination task (relative clockwisecounter-clockwise judgment. First, we show that a change in the dots' contrast polarity does not hamper performance. Next, we demonstrate that performance is unaffected by relocation of the Test stimulus in either retinotopic or spatiotopic coordinate frames. Finally, we show that an arrow-shaped cue presented during the delay interval between the Sample and Test stimulus, biases performance towards the direction of the arrow, although the cue itself is non-informative (it has no predictive value of the correct answer. These results indicate that the representation of motion direction in WM is independent of the physical features of the stimulus (polarity or position and has non-sensorial abstract qualities. It is plausible that an abstract mnemonic trace might be activated alongside a more basic, analogue representation of the stimulus. We speculate that the specific sensitivity of the mnemonic representation to the arrow-shaped symbol may stem from the long term learned association between direction and the hour in the clock.

Social coordination in toddler's word learning: interacting systems of perception and action

Science.gov (United States)

Pereira, Alfredo; Smith, Linda; Yu, Chen

2008-06-01

We measured turn-taking in terms of hand and head movements and asked if the global rhythm of the participants' body activity relates to word learning. Six dyads composed of parents and toddlers (M=18 months) interacted in a tabletop task wearing motion-tracking sensors on their hands and head. Parents were instructed to teach the labels of 10 novel objects and the child was later tested on a name-comprehension task. Using dynamic time warping, we compared the motion data of all body-part pairs, within and between partners. For every dyad, we also computed an overall measure of the quality of the interaction, that takes into consideration the state of interaction when the parent uttered an object label and the overall smoothness of the turn-taking. The overall interaction quality measure was correlated with the total number of words learned. In particular, head movements were inversely related to other partner's hand movements, and the degree of bodily coupling of parent and toddler predicted the words that children learned during the interaction. The implications of joint body dynamics to understanding joint coordination of activity in a social interaction, its scaffolding effect on the child's learning and its use in the development of artificial systems are discussed.

LAMI: A gesturally controlled three-dimensional stage Leap (Motion-based) Audio Mixing Interface

OpenAIRE

Wakefield, Jonathan P.; Dewey, Christopher; Gale, William

2017-01-01

Interface designers are increasingly exploring alternative approaches to user input/control. LAMI is a Leap (Motion-based) AMI which takes user’s hand gestures and maps these to a three-dimensional stage displayed on a computer monitor. Audio channels are visualised as spheres whose Y coordinate is spectral centroid and X and Z coordinates are controlled by hand position and represent pan and level respectively. Auxiliary send levels are controlled via wrist rotation and vertical hand positio...

Motion correction options in PET/MRI.

Science.gov (United States)

Catana, Ciprian

2015-05-01

Subject motion is unavoidable in clinical and research imaging studies. Breathing is the most important source of motion in whole-body PET and MRI studies, affecting not only thoracic organs but also those in the upper and even lower abdomen. The motion related to the pumping action of the heart is obviously relevant in high-resolution cardiac studies. These two sources of motion are periodic and predictable, at least to a first approximation, which means certain techniques can be used to control the motion (eg, by acquiring the data when the organ of interest is relatively at rest). Additionally, nonperiodic and unpredictable motion can also occur during the scan. One obvious limitation of methods relying on external devices (eg, respiratory bellows or the electrocardiogram signal to monitor the respiratory or cardiac cycle, respectively) to trigger or gate the data acquisition is that the complex motion of internal organs cannot be fully characterized. However, detailed information can be obtained using either the PET or MRI data (or both) allowing the more complete characterization of the motion field so that a motion model can be built. Such a model and the information derived from simple external devices can be used to minimize the effects of motion on the collected data. In the ideal case, all the events recorded during the PET scan would be used to generate a motion-free or corrected PET image. The detailed motion field can be used for this purpose by applying it to the PET data before, during, or after the image reconstruction. Integrating all these methods for motion control, characterization, and correction into a workflow that can be used for routine clinical studies is challenging but could potentially be extremely valuable given the improvement in image quality and reduction of motion-related image artifacts. Copyright © 2015 Elsevier Inc. All rights reserved.

The right frame of reference makes it simple: an example of introductory mechanics supported by video analysis of motion

International Nuclear Information System (INIS)

Klein, P; Gröber, S; Kuhn, J; Fleischhauer, A; Müller, A

2015-01-01

The selection and application of coordinate systems is an important issue in physics. However, considering different frames of references in a given problem sometimes seems un-intuitive and is difficult for students. We present a concrete problem of projectile motion which vividly demonstrates the value of considering different frames of references. We use this example to explore the effectiveness of video-based motion analysis (VBMA) as an instructional technique at university level in enhancing students’ understanding of the abstract concept of coordinate systems. A pilot study with 47 undergraduate students indicates that VBMA instruction improves conceptual understanding of this issue. (paper)

The right frame of reference makes it simple: an example of introductory mechanics supported by video analysis of motion

Science.gov (United States)

Klein, P.; Gröber, S.; Kuhn, J.; Fleischhauer, A.; Müller, A.

2015-01-01

The selection and application of coordinate systems is an important issue in physics. However, considering different frames of references in a given problem sometimes seems un-intuitive and is difficult for students. We present a concrete problem of projectile motion which vividly demonstrates the value of considering different frames of references. We use this example to explore the effectiveness of video-based motion analysis (VBMA) as an instructional technique at university level in enhancing students’ understanding of the abstract concept of coordinate systems. A pilot study with 47 undergraduate students indicates that VBMA instruction improves conceptual understanding of this issue.

Motion control, motion sickness, and the postural dynamics of mobile devices.

Science.gov (United States)

Stoffregen, Thomas A; Chen, Yi-Chou; Koslucher, Frank C

2014-04-01

Drivers are less likely than passengers to experience motion sickness, an effect that is important for any theoretical account of motion sickness etiology. We asked whether different types of control would affect the incidence of motion sickness, and whether any such effects would be related to participants' control of their own bodies. Participants played a video game on a tablet computer. In the Touch condition, the device was stationary and participants controlled the game exclusively through fingertip inputs via the device's touch screen. In the Tilt condition, participants held the device in their hands and moved the device to control some game functions. Results revealed that the incidence of motion sickness was greater in the Touch condition than in the Tilt condition. During game play, movement of the head and torso differed as a function of the type of game control. Before the onset of subjective symptoms of motion sickness, movement of the head and torso differed between participants who later reported motion sickness and those that did not. We discuss implications of these results for theories of motion sickness etiology.

A New Position Measurement System Using a Motion-Capture Camera for Wind Tunnel Tests

Directory of Open Access Journals (Sweden)

Yousok Kim

2013-09-01

Full Text Available Considering the characteristics of wind tunnel tests, a position measurement system that can minimize the effects on the flow of simulated wind must be established. In this study, a motion-capture camera was used to measure the displacement responses of structures in a wind tunnel test, and the applicability of the system was tested. A motion-capture system (MCS could output 3D coordinates using two-dimensional image coordinates obtained from the camera. Furthermore, this remote sensing system had some flexibility regarding lab installation because of its ability to measure at relatively long distances from the target structures. In this study, we performed wind tunnel tests on a pylon specimen and compared the measured responses of the MCS with the displacements measured with a laser displacement sensor (LDS. The results of the comparison revealed that the time-history displacement measurements from the MCS slightly exceeded those of the LDS. In addition, we confirmed the measuring reliability of the MCS by identifying the dynamic properties (natural frequency, damping ratio, and mode shape of the test specimen using system identification methods (frequency domain decomposition, FDD. By comparing the mode shape obtained using the aforementioned methods with that obtained using the LDS, we also confirmed that the MCS could construct a more accurate mode shape (bending-deflection mode shape with the 3D measurements.

Scaling laws and accurate small-amplitude stationary solution for the motion of a planar vortex filament in the Cartesian form of the local induction approximation.

Science.gov (United States)

Van Gorder, Robert A

2013-04-01

We provide a formulation of the local induction approximation (LIA) for the motion of a vortex filament in the Cartesian reference frame (the extrinsic coordinate system) which allows for scaling of the reference coordinate. For general monotone scalings of the reference coordinate, we derive an equation for the planar solution to the derivative nonlinear Schrödinger equation governing the LIA. We proceed to solve this equation perturbatively in small amplitude through an application of multiple-scales analysis, which allows for accurate computation of the period of the planar vortex filament. The perturbation result is shown to agree strongly with numerical simulations, and we also relate this solution back to the solution obtained in the arclength reference frame (the intrinsic coordinate system). Finally, we discuss nonmonotone coordinate scalings and their application for finding self-intersections of vortex filaments. These self-intersecting vortex filaments are likely unstable and collapse into other structures or dissipate completely.

First order sensitivity analysis of flexible multibody systems using absolute nodal coordinate formulation

International Nuclear Information System (INIS)

Pi Ting; Zhang Yunqing; Chen Liping

2012-01-01

Design sensitivity analysis of flexible multibody systems is important in optimizing the performance of mechanical systems. The choice of coordinates to describe the motion of multibody systems has a great influence on the efficiency and accuracy of both the dynamic and sensitivity analysis. In the flexible multibody system dynamics, both the floating frame of reference formulation (FFRF) and absolute nodal coordinate formulation (ANCF) are frequently utilized to describe flexibility, however, only the former has been used in design sensitivity analysis. In this article, ANCF, which has been recently developed and focuses on modeling of beams and plates in large deformation problems, is extended into design sensitivity analysis of flexible multibody systems. The Motion equations of a constrained flexible multibody system are expressed as a set of index-3 differential algebraic equations (DAEs), in which the element elastic forces are defined using nonlinear strain-displacement relations. Both the direct differentiation method and adjoint variable method are performed to do sensitivity analysis and the related dynamic and sensitivity equations are integrated with HHT-I3 algorithm. In this paper, a new method to deduce system sensitivity equations is proposed. With this approach, the system sensitivity equations are constructed by assembling the element sensitivity equations with the help of invariant matrices, which results in the advantage that the complex symbolic differentiation of the dynamic equations is avoided when the flexible multibody system model is changed. Besides that, the dynamic and sensitivity equations formed with the proposed method can be efficiently integrated using HHT-I3 method, which makes the efficiency of the direct differentiation method comparable to that of the adjoint variable method when the number of design variables is not extremely large. All these improvements greatly enhance the application value of the direct differentiation

Multi-Robot Motion Planning: A Timed Automata Approach

DEFF Research Database (Denmark)

Quottrup, Michael Melholt; Bak, Thomas; Izadi-Zamanabadi, Roozbeh

2004-01-01

This paper describes how a network of interacting timed automata can be used to model, analyze, and verify motion planning problems in a scenario with multiple robotic vehicles. The method presupposes an infra-structure of robots with feed-back controllers obeying simple restriction on a planar...... grid. The automata formalism merely presents a high-level model of environment, robots and control, but allows composition and formal symbolic reasoning about coordinated solutions. Composition is achieved through synchronization, and the verification software UPPAAL is used for a symbolic verification...... then subsequently be used as a high-level motion plan for the robots. This paper reports on the timed automata framework, results of two verification experiments, promise of the approach, and gives a perspective for future research....

Multi-Robot Motion Planning: A Timed Automata Approach

DEFF Research Database (Denmark)

Quottrup, Michael Melholt; Bak, Thomas; Izadi-Zamanabadi, Roozbeh

This paper describes how a network of interacting timed automata can be used to model, analyze, and verify motion planning problems in a scenario with multiple robotic vehicles. The method presupposes an infra-structure of robots with feed-back controllers obeying simple restriction on a planar...... grid. The automata formalism merely presents a high-level model of environment, robots and control, but allows composition and formal symbolic reasoning about coordinated solutions. Composition is achieved through synchronization, and the verification software UPPAAL is used for a symbolic verification...... then subsequently be used as a high-level motion plan for the robots. This paper reports on the timed automata framework, results of two verification experiments, promise of the approach, and gives a perspective for future research....

Cognitive Motor Coordination Training Improves Mental Rotation Performance in Primary School-Aged Children

Science.gov (United States)

Pietsch, Stefanie; Böttcher, Caroline; Jansen, Petra

2017-01-01

The long-term physical activity in specific sport activities can change the quality of mental rotation performance. This study investigates the influence of "Life Kinetik"--a motion program with tasks of cognition and motor coordination--on mental rotation performance of 44 primary school-aged children. While the experimental group…

Different coordination and flexibility of the spine and pelvis during lateral bending between young and older adults.

Science.gov (United States)

Sung, Paul S

2016-04-01

This study examined coordination of the spine and pelvis during lateral bending of the trunk in older adults. Thirty-four healthy subjects (17 young and 17 older adults) demonstrated lateral bending at a controlled speed while holding a bar at approximately 180 degrees of shoulder flexion. Kinematic data collection was completed on the thoracic spine, lumbar spine, and pelvis. The coupling angle was calculated to examine the thorax-lumbar, lumbar-pelvis, and thorax-pelvis coordination patterns. The older adults demonstrated a reduced range of motion (ROM) of the lumbar spine, while both groups revealed similar ROM in the thorax and in the pelvis. The coupling angle between the straightening and bending phases was different only for the older adults in the thorax-lumbar (23.4±8.0 vs. -1.6±4.4, p=0.004) and the lumbar-pelvis (65.4±7.2 vs. 86.1±7.8, p=0.001) coordination. However, there was no group difference in the thorax-pelvis coordination. These findings indicate that age-related changes in the lumbar region affect coordination patterns only during the bending phase. The older adults preserved a similar pattern of movement to the young adults during the straightening phase, but the coordination variability of the coupling angles was greater for the older adults than for the young adults. This movement pattern suggests that the older adults lacked consistent trunk control in an attempt to optimize lateral bending coordination. Copyright © 2016 Elsevier B.V. All rights reserved.

Corrections to the Hipparcos proper motions in declination for 807 stars

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Damljanović G.

2008-01-01

Full Text Available We used the data on latitude variations obtained from observations with 10 classical photographic zenith tubes (PZT in order to improve the Hipparcos proper motions in declinations µδ for 807 stars. Part of observing programmes, carried out during the last century for the purpose of studying the Earth's rotation, were realized by using PZT instruments. These observations were performed within in the intervals (tens of years much longer than that of the Hipparcos mission (less than 4 years. In addition, the annual number of observations for every PZT programme star is several hundreds on the average. Though the accuracy of the star coordinates in the Hipparcos Catalogue is by two orders of magnitude better than that of the star coordinates from the PZT observations, the large number of observations performed a much longer time interval makes it possible to correct the Hipparcos proper motions and to improve their accuracy with respect to the accuracy given in the Hipparcos Catalogue. Long term examinations of latitude and time variations were used to form the Earth Orientation Catalogue (EOC-2, aimed at a more accurate determination of positions and proper motions for the stars included. Our method of calculating the corrections of the proper motions in declination from the latitude variations is different from the method used in obtaining the EOC-2 Catalogue. Comparing the results we have established a good agreement between our µδ and the EOC-2 ones for the star sample used in the present paper.

Corrections to the Hipparcos Proper Motions in Declination for 807 Stars

Directory of Open Access Journals (Sweden)

Damljanović, G.

2008-12-01

Full Text Available We used the data on latitude variations obtained from observations with 10 classical photographic zenith tubes (PZT in order to improve the Hipparcos proper motions in declinations $mu_{delta} $ for 807 stars. Part of observing programmes, carried out during the last century for the purpose of studying the Earth's rotation, were realized by using PZT instruments. These observations were performed within in the intervals (tens of years much longer than that of the Hipparcos mission (less than 4 years. In addition, the annual number of observations for every PZT-programme star is several hundreds on the average. Though the accuracy of the star coordinates in the Hipparcos Catalogue is by two orders of magnitude better than that of the star coordinates from the PZT observations, the large number of observations performed a much longer time interval makes it possible to correct the Hipparcos proper motions and to improve their accuracy with respect to the accuracy given in the Hipparcos Catalogue. Long term examinations of latitude and time variations were used to form the Earth Orientation Catalogue (EOC-2, aimed at a more accurate determination of positions and proper motions for the stars included. Our method of calculating the corrections of the proper motions in declination from the latitude variations is different from the method used in obtaining the EOC-2 Catalogue. Comparing the results we have established a good agreement between our $mu_ {delta} $ and the EOC-2 ones for the star sample used in the present paper.

Motor coordination uses external spatial coordinates independent of developmental vision.

Science.gov (United States)

Heed, Tobias; Röder, Brigitte

2014-07-01

The constraints that guide bimanual movement coordination are informative about the processing principles underlying movement planning in humans. For example, symmetry relative to the body midline benefits finger and hand movements independent of hand posture. This symmetry constraint has been interpreted to indicate that movement coordination is guided by a perceptual code. Although it has been assumed implicitly that the perceptual system at the heart of this constraint is vision, this relationship has not been tested. Here, congenitally blind and sighted participants made symmetrical and non-symmetrical (that is, parallel) bimanual tapping and finger oscillation movements. For both groups, symmetrical movements were executed more correctly than parallel movements, independent of anatomical constraints like finger homology and hand posture. For the blind, the reliance on external spatial factors in movement coordination stands in stark contrast to their use of an anatomical reference frame in perceptual processing. Thus, the externally coded symmetry constraint evident in bimanual coordination can develop in the absence of the visual system, suggesting that the visual system is not critical for the establishment of an external-spatial reference frame in movement coordination. Copyright © 2014 Elsevier B.V. All rights reserved.

Hall effect in noncommutative coordinates

International Nuclear Information System (INIS)

Dayi, Oemer F.; Jellal, Ahmed

2002-01-01

We consider electrons in uniform external magnetic and electric fields which move on a plane whose coordinates are noncommuting. Spectrum and eigenfunctions of the related Hamiltonian are obtained. We derive the electric current whose expectation value gives the Hall effect in terms of an effective magnetic field. We present a receipt to find the action which can be utilized in path integrals for noncommuting coordinates. In terms of this action we calculate the related Aharonov-Bohm phase and show that it also yields the same effective magnetic field. When magnetic field is strong enough this phase becomes independent of magnetic field. Measurement of it may give some hints on spatial noncommutativity. The noncommutativity parameter θ can be tuned such that electrons moving in noncommutative coordinates are interpreted as either leading to the fractional quantum Hall effect or composite fermions in the usual coordinates

Scalable Photogrammetric Motion Capture System "mosca": Development and Application

Science.gov (United States)

Knyaz, V. A.

2015-05-01

Wide variety of applications (from industrial to entertainment) has a need for reliable and accurate 3D information about motion of an object and its parts. Very often the process of movement is rather fast as in cases of vehicle movement, sport biomechanics, animation of cartoon characters. Motion capture systems based on different physical principles are used for these purposes. The great potential for obtaining high accuracy and high degree of automation has vision-based system due to progress in image processing and analysis. Scalable inexpensive motion capture system is developed as a convenient and flexible tool for solving various tasks requiring 3D motion analysis. It is based on photogrammetric techniques of 3D measurements and provides high speed image acquisition, high accuracy of 3D measurements and highly automated processing of captured data. Depending on the application the system can be easily modified for different working areas from 100 mm to 10 m. The developed motion capture system uses from 2 to 4 technical vision cameras for video sequences of object motion acquisition. All cameras work in synchronization mode at frame rate up to 100 frames per second under the control of personal computer providing the possibility for accurate calculation of 3D coordinates of interest points. The system was used for a set of different applications fields and demonstrated high accuracy and high level of automation.

Attenuation relation for strong motion in Eastern Java based on appropriate database and method

Science.gov (United States)

Mahendra, Rian; Rohadi, Supriyanto; Rudyanto, Ariska

2017-07-01

The selection and determination of attenuation relation has become important for seismic hazard assessment in active seismic region. This research initially constructs the appropriate strong motion database, including site condition and type of the earthquake. The data set consisted of large number earthquakes of 5 ≤ Mw ≤ 9 and distance less than 500 km that occurred around Java from 2009 until 2016. The location and depth of earthquake are being relocated using double difference method to improve the quality of database. Strong motion data from twelve BMKG's accelerographs which are located in east Java is used. The site condition is known by using dominant period and Vs30. The type of earthquake is classified into crustal earthquake, interface, and intraslab based on slab geometry analysis. A total of 10 Ground Motion Prediction Equations (GMPEs) are tested using Likelihood (Scherbaum et al., 2004) and Euclidean Distance Ranking method (Kale and Akkar, 2012) with the associated database. The evaluation of these methods lead to a set of GMPEs that can be applied for seismic hazard in East Java where the strong motion data is collected. The result of these methods found that there is still high deviation of GMPEs, so the writer modified some GMPEs using inversion method. Validation was performed by analysing the attenuation curve of the selected GMPE and observation data in period 2015 up to 2016. The results show that the selected GMPE is suitable for estimated PGA value in East Java.

Analytical Analysis of Motion Separability

Directory of Open Access Journals (Sweden)

Marjan Hadian Jazi

2013-01-01

Full Text Available Motion segmentation is an important task in computer vision and several practical approaches have already been developed. A common approach to motion segmentation is to use the optical flow and formulate the segmentation problem using a linear approximation of the brightness constancy constraints. Although there are numerous solutions to solve this problem and their accuracies and reliabilities have been studied, the exact definition of the segmentation problem, its theoretical feasibility and the conditions for successful motion segmentation are yet to be derived. This paper presents a simplified theoretical framework for the prediction of feasibility, of segmentation of a two-dimensional linear equation system. A statistical definition of a separable motion (structure is presented and a relatively straightforward criterion for predicting the separability of two different motions in this framework is derived. The applicability of the proposed criterion for prediction of the existence of multiple motions in practice is examined using both synthetic and real image sequences. The prescribed separability criterion is useful in designing computer vision applications as it is solely based on the amount of relative motion and the scale of measurement noise.

Summary of ground motion prediction results for Nevada Test Site underground nuclear explosions related to the Yucca Mountain project

International Nuclear Information System (INIS)

Walck, M.C.

1996-10-01

This report summarizes available data on ground motions from underground nuclear explosions recorded on and near the Nevada Test Site, with emphasis on the ground motions recorded at stations on Yucca Mountain, the site of a potential high-level radioactive waste repository. Sandia National Laboratories, through the Weapons Test Seismic Investigations project, collected and analyzed ground motion data from NTS explosions over a 14-year period, from 1977 through 1990. By combining these data with available data from earlier, larger explosions, prediction equations for several ground motion parameters have been developed for the Test Site area for underground nuclear explosion sources. Also presented are available analyses of the relationship between surface and downhole motions and spectra and relevant crustal velocity structure information for Yucca Mountain derived from the explosion data. The data and associated analyses demonstrate that ground motions at Yucca Mountain from nuclear tests have been at levels lower than would be expected from moderate to large earthquakes in the region; thus nuclear explosions, while located relatively close, would not control seismic design criteria for the potential repository

Summary of ground motion prediction results for Nevada Test Site underground nuclear explosions related to the Yucca Mountain project

Energy Technology Data Exchange (ETDEWEB)

Walck, M.C.

1996-10-01

This report summarizes available data on ground motions from underground nuclear explosions recorded on and near the Nevada Test Site, with emphasis on the ground motions recorded at stations on Yucca Mountain, the site of a potential high-level radioactive waste repository. Sandia National Laboratories, through the Weapons Test Seismic Investigations project, collected and analyzed ground motion data from NTS explosions over a 14-year period, from 1977 through 1990. By combining these data with available data from earlier, larger explosions, prediction equations for several ground motion parameters have been developed for the Test Site area for underground nuclear explosion sources. Also presented are available analyses of the relationship between surface and downhole motions and spectra and relevant crustal velocity structure information for Yucca Mountain derived from the explosion data. The data and associated analyses demonstrate that ground motions at Yucca Mountain from nuclear tests have been at levels lower than would be expected from moderate to large earthquakes in the region; thus nuclear explosions, while located relatively close, would not control seismic design criteria for the potential repository.

Rocking or rolling--perception of ambiguous motion after returning from space.

Directory of Open Access Journals (Sweden)

Gilles Clément

Full Text Available The central nervous system must resolve the ambiguity of inertial motion sensory cues in order to derive an accurate representation of spatial orientation. Adaptive changes during spaceflight in how the brain integrates vestibular cues with other sensory information can lead to impaired movement coordination, vertigo, spatial disorientation, and perceptual illusions after return to Earth. The purpose of this study was to compare tilt and translation motion perception in astronauts before and after returning from spaceflight. We hypothesized that these stimuli would be the most ambiguous in the low-frequency range (i.e., at about 0.3 Hz where the linear acceleration can be interpreted either as a translation or as a tilt relative to gravity. Verbal reports were obtained in eleven astronauts tested using a motion-based tilt-translation device and a variable radius centrifuge before and after flying for two weeks on board the Space Shuttle. Consistent with previous studies, roll tilt perception was overestimated shortly after spaceflight and then recovered with 1-2 days. During dynamic linear acceleration (0.15-0.6 Hz, ±1.7 m/s2 perception of translation was also overestimated immediately after flight. Recovery to baseline was observed after 2 days for lateral translation and 8 days for fore-aft translation. These results suggest that there was a shift in the frequency dynamic of tilt-translation motion perception after adaptation to weightlessness. These results have implications for manual control during landing of a space vehicle after exposure to microgravity, as it will be the case for human asteroid and Mars missions.

Multi-Robot Motion Planning: A Timed Automata Approach

OpenAIRE

Quottrup, Michael Melholt; Bak, Thomas; Izadi-Zamanabadi, Roozbeh

2004-01-01

This paper describes how a network of interacting timed automata can be used to model, analyze, and verify motion planning problems in a scenario with multiple robotic vehicles. The method presupposes an infra-structure of robots with feed-back controllers obeying simple restriction on a planar grid. The automata formalism merely presents a high-level model of environment, robots and control, but allows composition and formal symbolic reasoning about coordinated solutions. Composition is achi...

Assessment of intersegmental coordination of rats during walking at different speeds - Application of continuous relative phase

DEFF Research Database (Denmark)

Raffalt, Peter Christian; Nielsen, Louise R; Madsen, Stefan

2018-01-01

of the CRP (ACRP) and DP and on the mean ACRP and mean DP was established by statistical parametric mapping (SPM) and a one-way ANOVA for repeated measures. Absolute and relative reliability were assessed by measurement error and intra-class correlation coefficient. The SPM analysis revealed time dependent......The present study investigated the feasibility and reliability of continuous relative phase (CRP) and deviation phase (DP) to assess intersegmental hind limb coordination pattern and coordination variability in rats during walking. Twenty-six adult rats walked at 8 m/min, 12 m/min and 16 m....../min while two-dimensional kinematics were recorded. Segment angles and segment angular velocities of the paw, shank and thigh on the left hind-limb were extracted from 15 strides and CRP was calculated for the paw-shank and shank-thigh coupling. The effect of walking speed on the time point average curve...

Relative Vessel Motion Tracking using Sensor Fusion, Aruco Markers, and MRU Sensors

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Sondre Sanden Tordal

2017-04-01

Full Text Available This paper presents a novel approach for estimating the relative motion between two moving offshore vessels. The method is based on a sensor fusion algorithm including a vision system and two motion reference units (MRUs. The vision system makes use of the open-source computer vision library OpenCV and a cube with Aruco markers placed onto each of the cube sides. The Extended Quaternion Kalman Filter (EQKF is used for bad pose rejection for the vision system. The presented sensor fusion algorithm is based on the Indirect Feedforward Kalman Filter for error estimation. The system is self-calibrating in the sense that the Aruco cube can be placed in an arbitrary location on the secondary vessel. Experimental 6-DOF results demonstrate the accuracy and efficiency of the proposed sensor fusion method compared with the internal joint sensors of two Stewart platforms and the industrial robot. The standard deviation error was found to be 31mm or better when the Arcuo cube was placed at three different locations.

Geometrical determination of the constant of motion in General Relativity

International Nuclear Information System (INIS)

Catoni, F.; Cannata, R.; Zampetti, P.

2009-01-01

In recent time a theorem, due to E. Beltrami, through which the integration of the geodesic equations of a curved manifold is obtained by means of a merely geometric method, has been revisited. This way of dealing with the problem is well in accordance with the geometric spirit of the Theory of General Relativity. In this paper we show another relevant consequence of this method. Actually, the constants of the motion, introduced in this geometrical way that is completely independent of Newton theory, are related to the conservation laws for test particles in the Einstein theory. These conservation laws may be compared with the conservation laws of Newton. In particular, by the conservation of energy (E) and the L z component of angular momentum, the equivalence of the conservation laws for the Schwarzschild field is verified and the difference between Newton and Einstein theories for the rotating bodies (Kerr metric) is obtained in a straightforward way.

Reorganization of finger coordination patterns through motor exploration in individuals after stroke.

Science.gov (United States)

Ranganathan, Rajiv

2017-09-11

Impairment of hand and finger function after stroke is common and affects the ability to perform activities of daily living. Even though many of these coordination deficits such as finger individuation have been well characterized, it is critical to understand how stroke survivors learn to explore and reorganize their finger coordination patterns for optimizing rehabilitation. In this study, I examine the use of a body-machine interface to assess how participants explore their movement repertoire, and how this changes with continued practice. Ten participants with chronic stroke wore a data glove and the finger joint angles were mapped on to the position of a cursor on a screen. The task of the participants was to move the cursor back and forth between two specified targets on a screen. Critically, the map between the finger movements and cursor motion was altered so that participants sometimes had to generate coordination patterns that required finger individuation. There were two phases to the experiment - an initial assessment phase on day 1, followed by a learning phase (days 2-5) where participants trained to reorganize their coordination patterns. Participants showed difficulty in performing tasks which had maps that required finger individuation, and the degree to which they explored their movement repertoire was directly related to clinical tests of hand function. However, over four sessions of practice, participants were able to learn to reorganize their finger movement coordination pattern and improve their performance. Moreover, training also resulted in improvements in movement repertoire outside of the context of the specific task during free exploration. Stroke survivors show deficits in movement repertoire in their paretic hand, but facilitating movement exploration during training can increase the movement repertoire. This suggests that exploration may be an important element of rehabilitation to regain optimal function.

Managing interteam coordination within and between organizations

NARCIS (Netherlands)

de Vries, Thomas Arend

2015-01-01

To accomplish complex tasks and effectively respond to environmental contingencies, teams must coordinate task-related issues with other teams (i.e., interteam coordination). Regrettably, interteam coordination is often complicated by misunderstandings that can arise from differences in teams’

Research of Short-range Missile Motion in Terms of Different Wind Loads

Directory of Open Access Journals (Sweden)

A. N. Klishin

2015-01-01

Full Text Available When modeling the aircraft motion it is advisable to choose a particular model of the Earth, depending both on the task and on the required accuracy of calculation. The article describes various models of the Earth, such as the flat Earth with a plane-parallel field of gravity, spherical and non-rotating Earth with a plane-parallel field of gravity, spherical and non-rotating Earth with a central gravitational field, spherical and non-rotating Earth, taking into account the polar flattening of the Earth, spherical Earth based compression and polar daily rotation. The article also considers the influence of these models on the motion of the selected aircraft.To date, there is technical equipment to provide highly accurate description of the Earthshape, gravitational field, etc. The improved accuracy of the Earth model description results in more correct description of the trajectory and motion parameters of a ballistic missile. However, for short ranges (10-20 km this accuracy is not essential, and, furthermore, it increases time of calculation. Therefore, there is a problem of choosing the optimal description of the Earth parameters.The motion in the model of the Earth, which takes into account a daily rotation of the planet and polar flattening, is discussed in more detail, and the geographical latitude impact on coordinates of the points of fall of a ballistic missile is analyzed on the basis of obtained graphs.The article individually considers a problem of the wind effect on the aircraft motion and defines dependences of the missile motion on the parameters of different wind loads, such as wind speed and height of its action.A mathematical model of the missile motion was built and numerically integrated, using the Runge-Kutta 4th order method, for implementation and subsequent analysis.Based on the analysis of the calculation results in the abovementioned models of the Earth, differences in impact of these models on the parameters of the

Motion coordination affects movement parameters in a joint pick-and-place task

DEFF Research Database (Denmark)

Vesper, Cordula; Soutschek, Alexander; Schubö, Anna

2009-01-01

This study examined influences of social context on movement parameters in a pick-and-place task. Participants’ motion trajectories were recorded while they performed sequences of natural movements either working side-by-side with a partner or alone. It was expected that movement parameters would...... person performed the task while being observed by the partner. Results indicate that participants adapted their movements temporally and spatially to the joint action situation: Overall movement duration was shorter, and mean and maximum velocity was higher when actually working together than when...... action tasks....

Non-linear Response to a Type of Seismic Input Motion. Additional Information

International Nuclear Information System (INIS)

2011-06-01

This publication reports the results and findings of a coordinated research project on the safety significance of near-field earthquakes in the design of nuclear power plants. It describes the outcome of a benchmark exercise conducted by a number of institutions on the effects of low to moderate magnitude near-field earthquakes, comparing model analytical simulations with the results of a shaking test performed in France on a physical model of a conventional shear-wall structure. The results build the basis for proposals for possible evolution of engineering practices in order to realistically take into account the effects of near-field earthquakes. A CD is attached that contains the List of participants; Summary of the Research Coordination Meetings; Description of the Camus data; Description of the Japanese input motions: near-field earthquakes observed recently in Japan; Description of the output requested of the IAEA CRP participants; Summary of the participants' modelling; Results of Benchmark Step 1, 2 and 3; Scientific background on classification of seismic loads as primary or secondary; and Japanese practice on nonlinear seismic response analysis of safety related important structures.

Movement-related theta rhythm in humans: coordinating self-directed hippocampal learning.

Directory of Open Access Journals (Sweden)

Raphael Kaplan

Full Text Available The hippocampus is crucial for episodic or declarative memory and the theta rhythm has been implicated in mnemonic processing, but the functional contribution of theta to memory remains the subject of intense speculation. Recent evidence suggests that the hippocampus might function as a network hub for volitional learning. In contrast to human experiments, electrophysiological recordings in the hippocampus of behaving rodents are dominated by theta oscillations reflecting volitional movement, which has been linked to spatial exploration and encoding. This literature makes the surprising cross-species prediction that the human hippocampal theta rhythm supports memory by coordinating exploratory movements in the service of self-directed learning. We examined the links between theta, spatial exploration, and memory encoding by designing an interactive human spatial navigation paradigm combined with multimodal neuroimaging. We used both non-invasive whole-head Magnetoencephalography (MEG to look at theta oscillations and Functional Magnetic Resonance Imaging (fMRI to look at brain regions associated with volitional movement and learning. We found that theta power increases during the self-initiation of virtual movement, additionally correlating with subsequent memory performance and environmental familiarity. Performance-related hippocampal theta increases were observed during a static pre-navigation retrieval phase, where planning for subsequent navigation occurred. Furthermore, periods of the task showing movement-related theta increases showed decreased fMRI activity in the parahippocampus and increased activity in the hippocampus and other brain regions that strikingly overlap with the previously observed volitional learning network (the reverse pattern was seen for stationary periods. These fMRI changes also correlated with participant's performance. Our findings suggest that the human hippocampal theta rhythm supports memory by coordinating

Learning Grasp Strategies Composed of Contact Relative Motions

Science.gov (United States)

Platt, Robert, Jr.

2007-01-01

Of central importance to grasp synthesis algorithms are the assumptions made about the object to be grasped and the sensory information that is available. Many approaches avoid the issue of sensing entirely by assuming that complete information is available. In contrast, this paper proposes an approach to grasp synthesis expressed in terms of units of control that simultaneously change the contact configuration and sense information about the object and the relative manipulator-object pose. These units of control, known as contact relative motions (CRMs), allow the grasp synthesis problem to be recast as an optimal control problem where the goal is to find a strategy for executing CRMs that leads to a grasp in the shortest number of steps. An experiment is described that uses Robonaut, the NASA-JSC space humanoid, to show that CRMs are a viable means of synthesizing grasps. However, because of the limited amount of information that a single CRM can sense, the optimal control problem may be partially observable. This paper proposes expressing the problem as a k-order Markov Decision Process (MDP) and solving it using Reinforcement Learning. This approach is tested in a simulation of a two-contact manipulator that learns to grasp an object. Grasp strategies learned in simulation are tested on the physical Robonaut platform and found to lead to grasp configurations consistently.

Wireless motion sensor network for monitoring motion in a process, wireless sensor node, reasoning node, and feedback and/or actuation node for such wireless motion sensor network

NARCIS (Netherlands)

Havinga, Paul J.M.; Marin Perianu, Raluca; Marin Perianu, Mihai

2010-01-01

Wireless motion sensor network for monitoring motion in a process comprising at least one wireless sensor node for measuring at least one physical quantity related to motion or orientation, feature extraction means for deriving a feature for the measured quantities, a wireless transmitter connected

An examination of the degrees of freedom of human jaw motion in speech and mastication.

Science.gov (United States)

Ostry, D J; Vatikiotis-Bateson, E; Gribble, P L

1997-12-01

The kinematics of human jaw movements were assessed in terms of the three orientation angles and three positions that characterize the motion of the jaw as a rigid body. The analysis focused on the identification of the jaw's independent movement dimensions, and was based on an examination of jaw motion paths that were plotted in various combinations of linear and angular coordinate frames. Overall, both behaviors were characterized by independent motion in four degrees of freedom. In general, when jaw movements were plotted to show orientation in the sagittal plane as a function of horizontal position, relatively straight paths were observed. In speech, the slopes and intercepts of these paths varied depending on the phonetic material. The vertical position of the jaw was observed to shift up or down so as to displace the overall form of the sagittal plane motion path of the jaw. Yaw movements were small but independent of pitch, and vertical and horizontal position. In mastication, the slope and intercept of the relationship between pitch and horizontal position were affected by the type of food and its size. However, the range of variation was less than that observed in speech. When vertical jaw position was plotted as a function of horizontal position, the basic form of the path of the jaw was maintained but could be shifted vertically. In general, larger bolus diameters were associated with lower jaw positions throughout the movement. The timing of pitch and yaw motion differed. The most common pattern involved changes in pitch angle during jaw opening followed by a phase predominated by lateral motion (yaw). Thus, in both behaviors there was evidence of independent motion in pitch, yaw, horizontal position, and vertical position. This is consistent with the idea that motions in these degrees of freedom are independently controlled.

Coordination and variability in the elite female tennis serve.

Science.gov (United States)

Whiteside, David; Elliott, Bruce Clifford; Lay, Brendan; Reid, Machar

2015-01-01

Enhancing the understanding of coordination and variability in the tennis serve may be of interest to coaches as they work with players to improve performance. The current study examined coordinated joint rotations and variability in the lower limbs, trunk, serving arm and ball location in the elite female tennis serve. Pre-pubescent, pubescent and adult players performed maximal effort flat serves while a 22-camera 500 Hz motion analysis system captured three-dimensional body kinematics. Coordinated joint rotations in the lower limbs and trunk appeared most consistent at the time players left the ground, suggesting that they coordinate the proximal elements of the kinematic chain to ensure that they leave the ground at a consistent time, in a consistent posture. Variability in the two degrees of freedom at the elbow became significantly greater closer to impact in adults, possibly illustrating the mechanical adjustments (compensation) these players employed to manage the changing impact location from serve to serve. Despite the variable ball toss, the temporal composition of the serve was highly consistent and supports previous assertions that players use the location of the ball to regulate their movement. Future work should consider these associations in other populations, while coaches may use the current findings to improve female serve performance.

Newton\\'s equation of motion in the gravitational field of an oblate ...

African Journals Online (AJOL)

In this paper, we derived Newton's equation of motion for a satellite in the gravitational scalar field of a uniformly rotating, oblate spheriodal Earth using spheriodal coordinates. The resulting equation is solved for the corresponding precession and the result compared with similar ones. JONAMP Vol. 11 2007: pp. 279-286 ...

Equations-of-motion approach to a quantum theory of large-amplitude collective motion

International Nuclear Information System (INIS)

Klein, A.

1984-01-01

The equations-of-motion approach to large-amplitude collective motion is implemented both for systems of coupled bosons, also studied in a previous paper, and for systems of coupled fermions. For the fermion case, the underlying formulation is that provided by the generalized Hartree-Fock approximation (or generalized density matrix method). To obtain results valid in the semi-classical limit, as in most previous work, we compute the Wigner transform of quantum matrices in the representation in which collective coordinates are diagonal and keep only the leading contributions. Higher-order contributions can be retained, however, and, in any case, there is no ambiguity of requantization. The semi-classical limit is seen to comprise the dynamics of time-dependent Hartree-Fock theory (TDHF) and a classical canonicity condition. By utilizing a well-known parametrization of the manifold of Slater determinants in terms of classical canonical variables, we are able to derive and understand the equations of the adiabatic limit in full parallelism with the boson case. As in the previous paper, we can thus show: (i) to zero and first order in the adiabatic limit the physics is contained in Villar's equations; (ii) to second order there is consistency and no new conditions. The structure of the solution space (discussed thoroughly in the previous paper) is summarized. A discussion of associated variational principles is given. A form of the theory equivalent to self-consistent cranking is described. A method of solution is illustrated by working out several elementary examples. The relationship to previsous work, especially that of Zelevinsky and Marumori and coworkers is discussed briefly. Three appendices deal respectively with the equations-of-motion method, with useful properties of Slater determinants, and with some technical details associated with the fermion equations of motion. (orig.)

Micro practices of coordination based on complex adaptive systems: user needs and strategies for coordinating public health in Denmark.

Science.gov (United States)

Terkildsen, Morten Deleuran; Wittrup, Inge; Burau, Viola

2015-01-01

Many highly formalised approaches to coordination poorly fit public health and recent studies call for coordination based on complex adaptive systems. Our contribution is two-fold. Empirically, we focus on public health, and theoretically we build on the patient perspective and treat coordination as a process of contingent, two-level negotiations of user needs. The paper draws on the concept of user needs-based coordination and sees coordination as a process, whereby needs emerging from the life world of the user are made amenable to the health system through negotiations. The analysis is based on an explorative case study of a health promotion initiative in Denmark. It adopts an anthropological qualitative approach and uses a range of qualitative data. The analysis identifies four strategies of coordination: the coordinator focusing on the individual user or on relations with other professionals; and the manager coaching the coordinator or providing structural support. Crucially, the coordination strategies by management remain weak as they do not directly relate to specific user needs. In process of bottom-up negotiations user needs become blurred and this is especially a challenge for management. The study therefore calls for an increased focus on the level nature of negotiations to bridge the gap that currently weakens coordination strategies by management.

TH-EF-BRB-08: Robotic Motion Compensation for Radiation Therapy: A 6DOF Phantom Study

Energy Technology Data Exchange (ETDEWEB)

Belcher, AH; Liu, X; Wiersma, R [The University of Chicago, Chicago, IL (United States)

2016-06-15

Purpose: The high accuracy of frame-based stereotactic radiosurgery (SRS), which uses a rigid frame fixed to the patient’s skull, is offset by potential drawbacks of poor patient compliance and clinical workflow restrictions. Recent research into frameless SRS has so far resulted in reduced accuracy. In this study, we investigate the use of a novel 6 degree-of-freedom (6DOF) robotic head motion cancellation system that continuously detects and compensates for patient head motions during a SRS delivery. This approach has the potential to reduce invasiveness while still achieving accuracies better or equal to traditional frame-based SRS. Methods: A 6DOF parallel kinematics robotics stage was constructed, and controlled using an inverse kinematics-based motion compensation algorithm. A 6DOF stereoscopic infrared (IR) marker tracking system was used to monitor real-time motions at sub-millimeter and sub-degree levels. A novel 6DOF calibration technique was first applied to properly orient the camera coordinate frame to match that of the LINAC and robotic control frames. Simulated head motions were measured by the system, and the robotic stage responded to these 6DOF motions automatically, returning the reflective marker coordinate frame to its original position. Results: After the motions were introduced to the system in the phantom-based study, the robotic stage automatically and rapidly returned the phantom to LINAC isocenter. When errors exceeded the compensation lower threshold of 0.25 mm or 0.25 degrees, the system registered the 6DOF error and generated a cancellation trajectory. The system responded in less than 0.5 seconds and returned all axes to less than 0.1 mm and 0.1 degree after the 6DOF compensation was performed. Conclusion: The 6DOF real-time motion cancellation system was found to be effective at compensating for translational and rotational motions to current SRS requirements. This system can improve frameless SRS by automatically returning

TH-EF-BRB-08: Robotic Motion Compensation for Radiation Therapy: A 6DOF Phantom Study

International Nuclear Information System (INIS)

Belcher, AH; Liu, X; Wiersma, R

2016-01-01

Purpose: The high accuracy of frame-based stereotactic radiosurgery (SRS), which uses a rigid frame fixed to the patient’s skull, is offset by potential drawbacks of poor patient compliance and clinical workflow restrictions. Recent research into frameless SRS has so far resulted in reduced accuracy. In this study, we investigate the use of a novel 6 degree-of-freedom (6DOF) robotic head motion cancellation system that continuously detects and compensates for patient head motions during a SRS delivery. This approach has the potential to reduce invasiveness while still achieving accuracies better or equal to traditional frame-based SRS. Methods: A 6DOF parallel kinematics robotics stage was constructed, and controlled using an inverse kinematics-based motion compensation algorithm. A 6DOF stereoscopic infrared (IR) marker tracking system was used to monitor real-time motions at sub-millimeter and sub-degree levels. A novel 6DOF calibration technique was first applied to properly orient the camera coordinate frame to match that of the LINAC and robotic control frames. Simulated head motions were measured by the system, and the robotic stage responded to these 6DOF motions automatically, returning the reflective marker coordinate frame to its original position. Results: After the motions were introduced to the system in the phantom-based study, the robotic stage automatically and rapidly returned the phantom to LINAC isocenter. When errors exceeded the compensation lower threshold of 0.25 mm or 0.25 degrees, the system registered the 6DOF error and generated a cancellation trajectory. The system responded in less than 0.5 seconds and returned all axes to less than 0.1 mm and 0.1 degree after the 6DOF compensation was performed. Conclusion: The 6DOF real-time motion cancellation system was found to be effective at compensating for translational and rotational motions to current SRS requirements. This system can improve frameless SRS by automatically returning

Separation of variables for the nonlinear wave equation in polar coordinates

International Nuclear Information System (INIS)

Shermenev, Alexander

2004-01-01

Some classical types of nonlinear wave motion in polar coordinates are studied within quadratic approximation. When the nonlinear quadratic terms in the wave equation are arbitrary, the usual perturbation techniques used in polar coordinates leads to overdetermined systems of linear algebraic equations for the unknown coefficients. However, we show that these overdetermined systems are compatible with the special case of the nonlinear shallow water equation and express explicitly the coefficients of the first two harmonics as polynomials of the Bessel functions of radius and of the trigonometric functions of angle. It gives a series of solutions to the nonlinear shallow water equation that are periodic in time and found with the same accuracy as the equation is derived

A study of collective coordinates and dynamical groups in nuclear theory

International Nuclear Information System (INIS)

Papadopolos, Z.

1983-01-01

Lie-algebraic techniques for the group action on manifolds given as a direct product of coset spaces and group manifolds are developed. The microscopic realisation of the Mass Quadrupole Collective Model (MQC) in the S0(3)xSO(n) and GLsub(+)(3, R)xSO(n) schemes is studied. The problem of the separation of the kinetic energy and the velocity field into a collective and an intrinsic part is analyzed. Different coordinate schemes in phase space for the U(n)-invariant collective motion and the U(3) dynamical group are introduced. In the GL(3,C)xU(n) scheme, the invariant volume element in the new coordinates and a completely orthonormal basis is constructed. (orig.) [de

[The coordination betwen health and social services in the care of people with severe mental disorders].

Science.gov (United States)

López Alvarez, Marcelino; Laviana Cuetos, Margarita

2016-01-01

Coordination between health and social services is a key point in caring for an increasing number of people affected by different types of health problems. The change in demographic and epidemiological patterns in our societies evidences the need of this coordination, usually not covered by our care systems. A sector in which the coordination is particularly important is the care of people with disabilities related to the suffering from severe mental disorders. This is a field that has been too long on the sidelines of the general health and social care systems as a result of the social stigma and traditional psychiatric institutions, setting in motion a vicious circle that must be broken in order to identify and to respond to the needs of such persons. In fact, the processes of change towards community care, with targets for recovery and not mere palliative or marginalizing care, necessarily incorporate this coordination as a cornerstone strategy for social inclusion and citizenship. Although there are still significant gaps in this regard, especially in Spain. However, there are experiences of change, such as that of Andalusia, which set the tone for the development of a strategy for integrated care, whose foundations and main elements we try to summarize in the present article. Copyright © 2015 Elsevier España, S.L.U. All rights reserved.

From the Kinematics of Precession Motion to Generalized Rabi Cycles

Directory of Open Access Journals (Sweden)

Danail S. Brezov

2018-01-01

Full Text Available We use both vector-parameter and quaternion techniques to provide a thorough description of several classes of rotations, starting with coaxial angular velocity Ω of varying magnitude. Then, we fix the magnitude and let Ω precess at constant rate about the z-axis, which yields a particular solution to the free Euler dynamical equations in the case of axially symmetric inertial ellipsoid. The latter appears also in the description of spin precessions in NMR and quantum computing. As we show below, this problem has analytic solutions for a much larger class of motions determined by a simple condition relating the polar angle and z-projection of Ω (expressed in cylindrical coordinates, which are both time-dependent in the generic case. Relevant physical examples are also provided.

Yang-Mills gauge invariance of a space of Bose and Fermi coordinates

International Nuclear Information System (INIS)

Friedman, M.H.; Srivastava, Y.

1977-01-01

A complete formalism is developed for imposing Yang-Mills gauge invariance induced by general coordinate transformations on superspace (i.e., a space containing both commuting and anticommuting coordinates). The appropriate group is the graded pseudo-Lie group of real, general linear transformations on superspace analogous to the role played by GL(4,R) in general relativity. The construction of derivatives which transform covariantly under this group forces the introduction of a connection. In the usual gauge theories the connection is just the vector potential, whereas here we expect it to be a function of all the dynamical fields. In this purely affine theory, field strengths and our proposed equations of motion for them result in a self-sourced theory involving only the connection. However, we find that there exist solutions which permit us to define a metric for which an inverse does not exist. These solutions are associated with a spontaneous symmetry breakdown of the vacuum which yields only the Lorentz metric and with no restriction on the internal-symmetry group. This spontaneous symmetry breaking introduces a parameter with the dimensions of (mass) 2

Linearized motion estimation for articulated planes.

Science.gov (United States)

Datta, Ankur; Sheikh, Yaser; Kanade, Takeo

2011-04-01

In this paper, we describe the explicit application of articulation constraints for estimating the motion of a system of articulated planes. We relate articulations to the relative homography between planes and show that these articulations translate into linearized equality constraints on a linear least-squares system, which can be solved efficiently using a Karush-Kuhn-Tucker system. The articulation constraints can be applied for both gradient-based and feature-based motion estimation algorithms and to illustrate this, we describe a gradient-based motion estimation algorithm for an affine camera and a feature-based motion estimation algorithm for a projective camera that explicitly enforces articulation constraints. We show that explicit application of articulation constraints leads to numerically stable estimates of motion. The simultaneous computation of motion estimates for all of the articulated planes in a scene allows us to handle scene areas where there is limited texture information and areas that leave the field of view. Our results demonstrate the wide applicability of the algorithm in a variety of challenging real-world cases such as human body tracking, motion estimation of rigid, piecewise planar scenes, and motion estimation of triangulated meshes.

The relation between respiratory motion artifact correction and lung standardized uptake value

International Nuclear Information System (INIS)

Yin Lijie; Liu Xiaojian; Liu Jie; Xu Rui; Yan Jue

2014-01-01

PET/CT is playing an important role in disease diagnosis and therapeutic evaluation. But the respiratory motion artifact may bring trouble in diagnosis and therapy. There are many methods to correct the respiratory motion artifact. Respiratory gated PET/CT is applied most extensively of them. Using respiratory gated PET/CT to correct respiratory motion artifact can increase the maximum standardized uptake value of lung lesion obviously, thereby improving the quality of image and accuracy of diagnosis. (authors)

A Method for Mechanism Analysis of Frog Swimming Based on Motion Observation Experiments

Directory of Open Access Journals (Sweden)

Wei Zhang

2014-05-01

Full Text Available For understanding the mechanism of frog swimming under water and designing a frog-inspired swimming robot, kinematics of the frog body and trajectories of joints should be obtained. In this paper, an aquatic frog, Xenopus laevis, was chosen for analysis of swimming motions which were recorded by a high speed camera, and kinematic data were processed in a swimming data extraction platform. According to the shape features of the frog, we propose a method that the frog eyes are set as the natural data extraction markers for body motion, and kinematic data of joint trajectories are calculated by the contour points on the limbs. For the data processing, a pinhole camera model was built to transform the pixel coordinate system to world coordinate system, and the errors caused by the water refraction were analyzed and corrected. Finally, from the developed data extraction platform, the kinematic data for the analysis of swimming mechanism and design of frog-inspired robot were obtained.

Psychophysical evidence for auditory motion parallax.

Science.gov (United States)

Genzel, Daria; Schutte, Michael; Brimijoin, W Owen; MacNeilage, Paul R; Wiegrebe, Lutz

2018-04-17

Distance is important: From an ecological perspective, knowledge about the distance to either prey or predator is vital. However, the distance of an unknown sound source is particularly difficult to assess, especially in anechoic environments. In vision, changes in perspective resulting from observer motion produce a reliable, consistent, and unambiguous impression of depth known as motion parallax. Here we demonstrate with formal psychophysics that humans can exploit auditory motion parallax, i.e., the change in the dynamic binaural cues elicited by self-motion, to assess the relative depths of two sound sources. Our data show that sensitivity to relative depth is best when subjects move actively; performance deteriorates when subjects are moved by a motion platform or when the sound sources themselves move. This is true even though the dynamic binaural cues elicited by these three types of motion are identical. Our data demonstrate a perceptual strategy to segregate intermittent sound sources in depth and highlight the tight interaction between self-motion and binaural processing that allows assessment of the spatial layout of complex acoustic scenes.

A Motion Planning Approach to Studying Molecular Motions

KAUST Repository

Amato, Nancy M.; Tapia, Lydia; Thomas, Shawna

2010-01-01

While structurally very different, protein and RNA molecules share an important attribute. The motions they undergo are strongly related to the function they perform. For example, many diseases such as Mad Cow disease or Alzheimer's disease

UAV Communication Management and Coordination for Multitarget Tracking

Science.gov (United States)

2009-02-26

6.3 Weighted Trace Penalty 16 6.4 Results with WTP for ECTG 17 7 Multiple UAV Case 20 7.1 Extension of WTP 20 7.2 Coordinated sensor motion...growth by a weighted trace penalty ( WTP ) term, which is a product of the current covariancc trace and the minimum distance to observability (MDO) for a...Specifically, the terminal cost or ECTG term using the WTP has the form J(b) = JWTP(b) := iD(s, e) Tfc P\\ (6.1) where 7 is a positive constant, i is the

Motion control system of MAX IV Laboratory soft x-ray beamlines

International Nuclear Information System (INIS)

Sjöblom, Peter; Lindberg, Mirjam; Forsberg, Johan; Persson, Andreas G.; Urpelainen, Samuli; Såthe, Conny

2016-01-01

At the MAX IV Laboratory, five new soft x-ray beamlines are under development. The first is Species and it will be used to develop and set the standard of the control system, which will be common across the facility. All motion axes at MAX IV will be motorized using stepper motors steered by the IcePAP motion controller and a mixture of absolute and incremental encoders following a predefined coordinate system. The control system software is built in Tango and uses the Python-based Sardana framework. The user controls the entire beamline through a synoptic overview and Sardana is used to run the scans.

Unsteady motion and transition to turbulence in developing curved duct flow

International Nuclear Information System (INIS)

Arnal, M.; Firmino, F.; Humphrey, J.A.C.

1987-01-01

An experiment was performed to further the understanding of developing flows in curved ducts of square cross-section. Unlike most earlier works, attention was paid to investigating the time-dependent character of the motion. Mean and unsteady flow characteristics were determined using flow visualization and a laser-Doppler velocimeter. Only one velocity component, that aligned in the longitudinal (streamwise) coordinate direction, was measured. Notwithstanding, the time histories, autocorrelations and spectra derived reveal a time-periodic motion that becomes turbulent with increasing Reynolds number. The results are of intrinsic fundamental value and also illustrate the danger of imposing symmetry of the conservation equations on numerical solutions of this flow. 24 references

Motion control system of MAX IV Laboratory soft x-ray beamlines

Energy Technology Data Exchange (ETDEWEB)

Sjöblom, Peter, E-mail: peter.sjoblom@maxlab.lu.se; Lindberg, Mirjam, E-mail: mirjam.lindberg@maxlab.lu.se; Forsberg, Johan, E-mail: johan.forsberg@maxlab.lu.se; Persson, Andreas G., E-mail: andreas-g.persson@maxlab.lu.se; Urpelainen, Samuli, E-mail: samuli.urpelainen@maxlab.lu.se; Såthe, Conny, E-mail: conny.sathe@maxlab.lu.se [MAX IV Laboratory, Photongatan 2, 225 92 Lund (Sweden)

2016-07-27

At the MAX IV Laboratory, five new soft x-ray beamlines are under development. The first is Species and it will be used to develop and set the standard of the control system, which will be common across the facility. All motion axes at MAX IV will be motorized using stepper motors steered by the IcePAP motion controller and a mixture of absolute and incremental encoders following a predefined coordinate system. The control system software is built in Tango and uses the Python-based Sardana framework. The user controls the entire beamline through a synoptic overview and Sardana is used to run the scans.

Extract the Relational Information of Static Features and Motion Features for Human Activities Recognition in Videos

Directory of Open Access Journals (Sweden)

Li Yao

2016-01-01

Full Text Available Both static features and motion features have shown promising performance in human activities recognition task. However, the information included in these features is insufficient for complex human activities. In this paper, we propose extracting relational information of static features and motion features for human activities recognition. The videos are represented by a classical Bag-of-Word (BoW model which is useful in many works. To get a compact and discriminative codebook with small dimension, we employ the divisive algorithm based on KL-divergence to reconstruct the codebook. After that, to further capture strong relational information, we construct a bipartite graph to model the relationship between words of different feature set. Then we use a k-way partition to create a new codebook in which similar words are getting together. With this new codebook, videos can be represented by a new BoW vector with strong relational information. Moreover, we propose a method to compute new clusters from the divisive algorithm’s projective function. We test our work on the several datasets and obtain very promising results.

Evaluation of vertical coordinate and vertical mixing algorithms in the HYbrid-Coordinate Ocean Model (HYCOM)

Science.gov (United States)

Halliwell, George R.

Vertical coordinate and vertical mixing algorithms included in the HYbrid Coordinate Ocean Model (HYCOM) are evaluated in low-resolution climatological simulations of the Atlantic Ocean. The hybrid vertical coordinates are isopycnic in the deep ocean interior, but smoothly transition to level (pressure) coordinates near the ocean surface, to sigma coordinates in shallow water regions, and back again to level coordinates in very shallow water. By comparing simulations to climatology, the best model performance is realized using hybrid coordinates in conjunction with one of the three available differential vertical mixing models: the nonlocal K-Profile Parameterization, the NASA GISS level 2 turbulence closure, and the Mellor-Yamada level 2.5 turbulence closure. Good performance is also achieved using the quasi-slab Price-Weller-Pinkel dynamical instability model. Differences among these simulations are too small relative to other errors and biases to identify the "best" vertical mixing model for low-resolution climate simulations. Model performance deteriorates slightly when the Kraus-Turner slab mixed layer model is used with hybrid coordinates. This deterioration is smallest when solar radiation penetrates beneath the mixed layer and when shear instability mixing is included. A simulation performed using isopycnic coordinates to emulate the Miami Isopycnic Coordinate Ocean Model (MICOM), which uses Kraus-Turner mixing without penetrating shortwave radiation and shear instability mixing, demonstrates that the advantages of switching from isopycnic to hybrid coordinates and including more sophisticated turbulence closures outweigh the negative numerical effects of maintaining hybrid vertical coordinates.

Dimensionality reduction of collective motion by principal manifolds

Science.gov (United States)

Gajamannage, Kelum; Butail, Sachit; Porfiri, Maurizio; Bollt, Erik M.

2015-01-01

While the existence of low-dimensional embedding manifolds has been shown in patterns of collective motion, the current battery of nonlinear dimensionality reduction methods is not amenable to the analysis of such manifolds. This is mainly due to the necessary spectral decomposition step, which limits control over the mapping from the original high-dimensional space to the embedding space. Here, we propose an alternative approach that demands a two-dimensional embedding which topologically summarizes the high-dimensional data. In this sense, our approach is closely related to the construction of one-dimensional principal curves that minimize orthogonal error to data points subject to smoothness constraints. Specifically, we construct a two-dimensional principal manifold directly in the high-dimensional space using cubic smoothing splines, and define the embedding coordinates in terms of geodesic distances. Thus, the mapping from the high-dimensional data to the manifold is defined in terms of local coordinates. Through representative examples, we show that compared to existing nonlinear dimensionality reduction methods, the principal manifold retains the original structure even in noisy and sparse datasets. The principal manifold finding algorithm is applied to configurations obtained from a dynamical system of multiple agents simulating a complex maneuver called predator mobbing, and the resulting two-dimensional embedding is compared with that of a well-established nonlinear dimensionality reduction method.

Micro practices of coordination based on complex adaptive systems: user needs and strategies for coordinating public health in Denmark

Directory of Open Access Journals (Sweden)

Morten Deleuran Terkildsen

2015-09-01

Full Text Available Introduction: Many highly formalised approaches to coordination poorly fit public health and recent studies call for coordination based on complex adaptive systems. Our contribution is two-fold. Empirically, we focus on public health, and theoretically we build on the patient perspective and treat coordination as a process of contingent, two-level negotiations of user needs.Theory and Methods: The paper draws on the concept of user needs-based coordination and sees coordination as a process, whereby needs emerging from the life world of the user are made amenable to the health system through negotiations. The analysis is based on an explorative case study of a health promotion initiative in Denmark. It adopts an anthropological qualitative approach and uses a range of qualitative data.Results: The analysis identifies four strategies of coordination: the coordinator focusing on the individual user or on relations with other professionals; and the manager coaching the coordinator or providing structural support. Crucially, the coordination strategies by management remain weak as they do not directly relate to specific user needs.Discussion: In process of bottom-up negotiations user needs become blurred and this is especially a challenge for management. The study therefore calls for an increased focus on the level nature of negotiations to bridge the gap that currently weakens coordination strategies by management.

Spin crossover-induced colossal positive and negative thermal expansion in a nanoporous coordination framework material.

Science.gov (United States)

Mullaney, Benjamin R; Goux-Capes, Laurence; Price, David J; Chastanet, Guillaume; Létard, Jean-François; Kepert, Cameron J

2017-10-20

External control over the mechanical function of materials is paramount in the development of nanoscale machines. Yet, exploiting changes in atomic behaviour to produce controlled scalable motion is a formidable challenge. Here, we present an ultra-flexible coordination framework material in which a cooperative electronic transition induces an extreme abrupt change in the crystal lattice conformation. This arises due to a change in the preferred coordination character of Fe(II) sites at different spin states, generating scissor-type flexing of the crystal lattice. Diluting the framework with transition-inactive Ni(II) sites disrupts long-range communication of spin state through the lattice, producing a more gradual transition and continuous lattice movement, thus generating colossal positive and negative linear thermal expansion behaviour, with coefficients of thermal expansion an order of magnitude greater than previously reported. This study has wider implications in the development of advanced responsive structures, demonstrating electronic control over mechanical motion.

SU-E-J-57: First Development of Adapting to Intrafraction Relative Motion Between Prostate and Pelvic Lymph Nodes Targets

Energy Technology Data Exchange (ETDEWEB)

Ge, Y; Colvill, E; O’Brien, R; Keall, P [Radiation Physics Laboratory, University of Sydney, NSW (Australia); Booth, J [Northern Sydney Cancer Centre, Royal North Shore Hospital, Sydney, NSW (Australia)

2015-06-15

Purpose Large intrafraction relative motion of multiple targets is common in advanced head and neck, lung, abdominal, gynaecological and urological cancer, jeopardizing the treatment outcomes. The objective of this study is to develop a real-time adaptation strategy, for the first time, to accurately correct for the relative motion of multiple targets by reshaping the treatment field using the multi-leaf collimator (MLC). Methods The principle of tracking the simultaneously treated but differentially moving tumor targets is to determine the new aperture shape that conforms to the shifted targets. Three dimensional volumes representing the individual targets are projected to the beam’s eye view. The leaf openings falling inside each 2D projection will be shifted according to the measured motion of each target to form the new aperture shape. Based on the updated beam shape, new leaf positions will be determined with optimized trade-off between the target underdose and healthy tissue overdose, and considerations of the physical constraints of the MLC. Taking a prostate cancer patient with pelvic lymph node involvement as an example, a preliminary dosimetric study was conducted to demonstrate the potential treatment improvement compared to the state-of- art adaptation technique which shifts the whole beam to track only one target. Results The world-first intrafraction adaptation system capable of reshaping the beam to correct for the relative motion of multiple targets has been developed. The dose in the static nodes and small bowel are closer to the planned distribution and the V45 of small bowel is decreased from 110cc to 75cc, corresponding to a 30% reduction by this technique compared to the state-of-art adaptation technique. Conclusion The developed adaptation system to correct for intrafraction relative motion of multiple targets will guarantee the tumour coverage and thus enable PTV margin reduction to minimize the high target dose to the adjacent organs

Keep Meaning in Conversational Coordination

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Elena Clare Cuffari

2014-12-01

Full Text Available Coordination is a widely employed term across recent quantitative and qualitative approaches to intersubjectivity, particularly approaches that give embodiment and enaction central explanatory roles. With a focus on linguistic and bodily coordination in conversational contexts, I review the operational meaning of coordination in recent empirical research and related theorizing of embodied intersubjectivity. This discussion articulates what must be involved in treating linguistic meaning as dynamic processes of coordination. The coordination approach presents languaging as a set of dynamic self-organizing processes and actions on multiple timescales and across multiple modalities that come about and work in certain domains (those jointly constructed in social, interactive, high-order sense-making. These processes go beyond meaning at the level that is available to first-person experience. I take one crucial consequence of this to be the ubiquitously moral nature of languaging with others. Languaging coordinates experience, among other levels of behavior and event. Ethical effort is called for by the automatic autonomy-influencing forces of languaging as coordination.

Temporal ventriloquism along the path of apparent motion: speed perception under different spatial grouping principles.

Science.gov (United States)

Ogulmus, Cansu; Karacaoglu, Merve; Kafaligonul, Hulusi

2018-03-01

The coordination of intramodal perceptual grouping and crossmodal interactions plays a critical role in constructing coherent multisensory percepts. However, the basic principles underlying such coordinating mechanisms still remain unclear. By taking advantage of an illusion called temporal ventriloquism and its influences on perceived speed, we investigated how audiovisual interactions in time are modulated by the spatial grouping principles of vision. In our experiments, we manipulated the spatial grouping principles of proximity, uniform connectedness, and similarity/common fate in apparent motion displays. Observers compared the speed of apparent motions across different sound timing conditions. Our results revealed that the effects of sound timing (i.e., temporal ventriloquism effects) on perceived speed also existed in visual displays containing more than one object and were modulated by different spatial grouping principles. In particular, uniform connectedness was found to modulate these audiovisual interactions in time. The effect of sound timing on perceived speed was smaller when horizontal connecting bars were introduced along the path of apparent motion. When the objects in each apparent motion frame were not connected or connected with vertical bars, the sound timing was more influential compared to the horizontal bar conditions. Overall, our findings here suggest that the effects of sound timing on perceived speed exist in different spatial configurations and can be modulated by certain intramodal spatial grouping principles such as uniform connectedness.

The moving minimum audible angle is smaller during self motion than during source motion.

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W. Owen eBrimijoin

2014-09-01

Full Text Available We are rarely perfectly still: our heads rotate in three axes and move in three dimensions, constantly varying the spectral and binaural cues at the ear drums. In spite of this motion, static sound sources in the world are typically perceived as stable objects. This argues that the auditory system – in a manner not unlike the vestibulo-ocular reflex – works to compensate for self motion and stabilize our sensory representation of the world. We tested a prediction arising from this postulate: that self motion should be processed more accurately than source motion.We used an infrared motion tracking system to measure head angle, and real-time interpolation of head related impulse responses to create head-stabilized signals that appeared to remain fixed in space as the head turned. After being presented with pairs of simultaneous signals consisting of a man and a woman speaking a snippet of speech, normal and hearing impaired listeners were asked to report whether the female voice was to the left or the right of the male voice. In this way we measured the moving minimum audible angle (MMAA. This measurement was made while listeners were asked to turn their heads back and forth between ± 15° and the signals were stabilized in space. After this self-motion condition we measured MMAA in a second source-motion condition when listeners remained still and the virtual locations of the signals were moved using the trajectories from the first condition.For both normal and hearing impaired listeners, we found that the MMAA for signals moving relative to the head was ~1-2° smaller when the movement was the result of self motion than when it was the result of source motion, even though the motion with respect to the head was identical. These results as well as the results of past experiments suggest that spatial processing involves an ongoing and highly accurate comparison of spatial acoustic cues with self-motion cues.

Coordination in contractual relations: Some preliminary findings from the Malaysian housing industry

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Suraya Ismail

2008-12-01

Full Text Available The traditional general procurement route found in many housing projects in Malaysia is conceptualized as a governance structure following the transaction cost economics (TCE approach. This approach has been used to examine governance structures in different economic sectors in several countries but evidence of its use in the context of developing countries is limited. This lack of evidence has prompted the authors to conduct a preliminary study to ascertain whether a TCE approach can explain construction governance structures in developing countries. This research does not discuss the trade-off that governs the choice of hybrids, market or hierarchies for organizing transactions. Rather, it takes advantage of existing research to substantiate the specific properties of hybrid organizations as governance structures. The main focus is coordination. Coordination is specified at two levels. At Level 1 is the coordination of specialization (i.e. the formation of the project team members and at Level 2 is the coordination mode of the contracting parties (client and contractor and the agents involved (the lead designer and project manage r. A case survey method was adopted. Preliminary findings seem to suggest that clients have used hierarchical themes in the contracts and high powered incentives to coordinate with in the contracting parties. The research findings suggest that all participants involved in the sample studied used governance structures symptomatic of a hybrid organization.

Producing Coordinate Time Series for Iraq's CORS Site for Detection Geophysical Phenomena

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Oday Yaseen Mohamed Zeki Alhamadani

2018-01-01

Full Text Available Global Navigation Satellite Systems (GNSS have become an integral part of wide range of applications. One of these applications of GNSS is implementation of the cellular phone to locate the position of users and this technology has been employed in social media applications. Moreover, GNSS have been effectively employed in transportation, GIS, mobile satellite communications, and etc. On the other hand, the geomatics sciences use the GNSS for many practical and scientific applications such as surveying and mapping and monitoring, etc. In this study, the GNSS raw data of ISER CORS, which is located in the North of Iraq, are processed and analyzed to build up coordinate time series for the purpose of detection the Arabian tectonic plate motion over seven years and a half. Such coordinates time series have been produced very efficiently using GNSS Precise Point Positioning (PPP. The daily PPP results were processed, analyzed, and presented as coordinate time series using GPS Interactive Time Series Analysis. Furthermore, MATLAB (V.2013a is used in this study to computerize GITSA with Graphic User Interface (GUI. The objective of this study was to investigate both of the homogeneity and consistency of the Iraq CORSs GNSS raw data for detection any geophysical changes over long period of time. Additionally, this study aims to employ free online PPP services, such as CSRS_PPP software, for processing GNSS raw data for generation GNSS coordinate time series. The coordinate time series of ISER station showed a +20.9 mm per year, +27.2 mm per year, and -11.3 mm per year in the East, North, and up-down components, respectively. These findings showed a remarkable similarity with those obtained by long-term monitoring of Earth's crust deformation and movement based on global studies and this highlights the importance of using GNSS for monitoring the movement of tectonic plate motion based on CORS and online GNSS data processing services over long period of

A Dynamic Coordination Mechanism Using Adjustable Autonomy

NARCIS (Netherlands)

Neef, R.M.; Vecht, B. van der; Dignum, F.; Meyer, J.J.C.

2008-01-01

Agents in an organization need to coordinate their actions in order to reach the organizational goals. This research describes the relation between types of coordination and the autonomy of actors. In an experimental setting we show that there is not one best way to coordinate in all situations. The

A Dynamic Coordination Mechanism Using Adjustable Autonomy

NARCIS (Netherlands)

Vecht, B. van der; Dignum, F.; Meyer, J.J.C.; Neef, R.M.

2007-01-01

Agents in an organization need to coordinate their actions in order to reach the organizational goals. This research describes the relation between types of coordination and the autonomy of actors. In an experimental setting we show that there is not one best way to coordinate in all situations. The

Overview of the relations earthquake source parameters and the specification of strong ground motion for design purposes

International Nuclear Information System (INIS)

Bernreuter, D.L.

1977-08-01

One of the most important steps in the seismic design process is the specification of the appropriate ground motion to be input into the design analysis. From the point-of-view of engineering design analysis, the important parameters are peak ground acceleration, spectral shape and peak spectral levels. In a few cases, ground displacement is a useful parameter. The earthquake is usually specified by giving its magnitude and either the epicentral distance or the distance of the closest point on the causitive fault to the site. Typically, the appropriate ground motion parameters are obtained using the specified magnitude and distance in equations obtained from regression analysis among the appropriate variables. Two major difficulties with such an approach are: magnitude is not the best parameter to use to define the strength of an earthquake, and little near-field data is available to establish the appropriate form for the attenuation of the ground motion with distance, source size and strength. These difficulties are important for designing a critical facility; i.e., one for which a very low risk of exceeding the design ground motion is required. Examples of such structures are nuclear power plants, schools and hospitals. for such facilities, a better understanding of the relation between the ground motion and the important earthquake source parameters could be very useful for several reasons

Post-Newtonian Reference Frames For Advanced Theory Of The Lunar Motion And For A New Generation Of Lunar Laser Ranging

International Nuclear Information System (INIS)

Xie, Y.; Kopeikon, S.

2010-01-01

We overview a set of post-Newtonian reference frames for a comprehensive study of the orbital dynamics and rotational motion of Moon and Earth by means of lunar laser ranging (LLR). We employ a scalar-tensor theory of gravity depending on two post-Newtonian parameters, and , and utilize the relativistic resolutions on reference frames adopted by the International Astronomical Union (IAU) in 2000. We assume that the solar system is isolated and space-time is asymptotically flat at infinity. The primary reference frame covers the entire space-time, has its origin at the solar-system barycenter (SSB) and spatial axes stretching up to infinity. The SSB frame is not rotating with respect to a set of distant quasars that are forming the International Celestial Reference Frame (ICRF). The secondary reference frame has its origin at the Earth-Moon barycenter (EMB). The EMB frame is locally-inertial and is not rotating dynamically in the sense that equation of motion of a test particle moving with respect to the EMB frame, does not contain the Coriolis and centripetal forces. Two other local frames geocentric (GRF) and selenocentric (SRF) have their origins at the center of mass of Earth and Moon respectively and do not rotate dynamically. Each local frame is subject to the geodetic precession both with respect to other local frames and with respect to the ICRF because of their relative motion with respect to each other. Theoretical advantage of the dynamically non-rotating local frames is in a more simple mathematical description. Each local frame can be aligned with the axes of ICRF after applying the matrix of the relativistic precession. The set of one global and three local frames is introduced in order to fully decouple the relative motion of Moon with respect to Earth from the orbital motion of the Earth-Moon barycenter as well as to connect the coordinate description of the lunar motion, an observer on Earth, and a retro-reflector on Moon to directly measurable

Post-Newtonian reference frames for advanced theory of the lunar motion and for a new generation of Lunar laser ranging

International Nuclear Information System (INIS)

Xie, Yi.; Kopeikin, S.

2010-01-01

We overview a set of post-Newtonian reference frames for a comprehensive study of the orbital dynamics and rotational motion of Moon and Earth by means of lunar laser ranging. We employ a scalar-tensor theory of gravity depending on two post-Newtonian parameters, and utilize the relativistic resolutions on reference frames adopted by the International Astronomical Union in 2000. We assume that the solar system is isolated and space-time is asymptotically flat at infinity. The primary reference frame covers the entire space-time, has its origin at the solar-system barycenter and spatial axes stretching up to infinity. The solar-system barycenter frame is not rotating with respect to a set of distant quasars that are forming the International Celestial Reference Frame. The secondary reference frame has its origin at the Earth-Moon barycenter. The Earth-Moon barycenter frame is locally-inertial and is not rotating dynamically in the sense that equation of motion of a test particle moving with respect to the Earth-Moon barycenter frame, does not contain the Coriolis and centripetal forces. Two other local frames-geocentric and seleno centric-have their origins at the center of mass of Earth and Moon respectively and do not rotate dynamically. Each local frame is subject to the geodetic precession both with respect to other local frames and with respect to the International Celestial Reference Frame because of their relative motion with respect to each other. Theoretical advantage of the dynamically non-rotating local frames is in a more simple mathematical description. Each local frame can be aligned with the axes of International Celestial Reference Frame after applying the matrix of the relativistic precession. The set of one global and three local frames is introduced in order to fully decouple the relative motion of Moon with respect to Earth from the orbital motion of the Earth-Moon barycenter as well as to connect the coordinate description of the lunar motion

Auditory motion capturing ambiguous visual motion

Directory of Open Access Journals (Sweden)

Arjen eAlink

2012-01-01

Full Text Available In this study, it is demonstrated that moving sounds have an effect on the direction in which one sees visual stimuli move. During the main experiment sounds were presented consecutively at four speaker locations inducing left- or rightwards auditory apparent motion. On the path of auditory apparent motion, visual apparent motion stimuli were presented with a high degree of directional ambiguity. The main outcome of this experiment is that our participants perceived visual apparent motion stimuli that were ambiguous (equally likely to be perceived as moving left- or rightwards more often as moving in the same direction than in the opposite direction of auditory apparent motion. During the control experiment we replicated this finding and found no effect of sound motion direction on eye movements. This indicates that auditory motion can capture our visual motion percept when visual motion direction is insufficiently determinate without affecting eye movements.

Motion of the Rivera plate since 10 Ma relative to the Pacific and North American plates and the mantle

Science.gov (United States)

DeMets, Charles; Traylen, Stephen

2000-03-01

To better understand the influence of Rivera plate kinematics on the geodynamic evolution of western Mexico, we use more than 1400 crossings of seafloor spreading magnetic lineations along the Pacific-Rivera rise and northern Mathematician ridge to solve for rotations of the Rivera plate relative to the underlying mantle and the Pacific and North American plates at 14 times since 9.9 Ma. Our comparison of magnetic anomaly crossings from the undeformed Pacific plate to their counterparts on the Rivera plate indicates that significant areas of the Rivera plate have deformed since 9.9 Ma. Dextral shear along the southern edge of the plate from 3.3-2.2 Ma during a regional plate boundary reorganization deformed the Rivera plate farther into its interior than previously recognized. In addition, seafloor located north of two rupture zones within the Rivera plate sutured to North America after 1.5 Ma. Anomaly crossings from these two deformed regions thus cannot be used to reconstruct motion of the Rivera plate. Finite rotations that best reconstruct Pacific plate anomaly crossings onto their undeformed counterparts on the Rivera plate yield stage spreading rates that decrease gradually by 10% between 10 and 3.6 Ma, decrease rapidly by 20% after ˜3.6 Ma, and recover after 1 Ma. The slowdown in Pacific-Rivera seafloor spreading at 3.6 Ma coincided with the onset of dextral shear across the then-incipient southern boundary of the Rivera plate with the Pacific plate. The available evidence indicates that the Rivera plate has been an independent microplate since at least 10 Ma, contrary to published assertions that it fragmented from the Cocos plate at ˜5 Ma. Motion of the Rivera plate relative to North America has changed significantly since 10 Ma, in concert with significant changes in Pacific-Rivera motion. A significant and robust feature of Rivera-North America motion not previously recognized is the cessation of margin-normal convergence and thus subduction from 2

Superluminal motion (review)

Science.gov (United States)

Malykin, G. B.; Romanets, E. A.

2012-06-01

Prior to the development of Special Relativity, no restrictions were imposed on the velocity of the motion of particles and material bodies, as well as on energy transfer and signal propagation. At the end of the 19th century and the beginning of the 20th century, it was shown that a charge that moves at a velocity faster than the speed of light in an optical medium, in particular, in vacuum, gives rise to impact radiation, which later was termed the Vavilov-Cherenkov radiation. Shortly after the development of Special Relativity, some researchers considered the possibility of superluminal motion. In 1923, the Soviet physicist L.Ya. Strum suggested the existence of tachyons, which, however, have not been discovered yet. Superluminal motions can occur only for images, e.g., for so-called "light spots," which were considered in 1972 by V.L. Ginzburg and B.M. Bolotovskii. These spots can move with a superluminal phase velocity but are incapable of transferring energy and information. Nevertheless, these light spots may induce quite real generation of microwave radiation in closed waveguides and create the Vavilov-Cherenkov radiation in vacuum. In this work, we consider various paradoxes, illusions, and artifacts associated with superluminal motion.

RELATIONS BETWEEN ANTHROPOMETRIC CHARACTERISTICS AND COORDINATION IN PEOPLE WITH ABOVE-AVERAGE MOTOR ABILITIES

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Milan Cvetković

2011-09-01

Full Text Available The sample of 149 male persons whose average age is 20.15 in decimal years (±0.83, and all of whom are students at the Faculty of Sport and Physical Education, underwent a battery of tests consisting of 17 anthropometric measures taken from the measures index of the International Biological Program and 4 tests designed to assess coordination as follows: Coordination with stick, Hand and leg drumming, Nonrhythmic drumming and Slalom with three balls. One statistically significant canonical correlation was determined by means of the canonical correlation analysis. The isolated canonical correlation from the space of coordination variables, was the one used for assessment of coordination of the whole body – Coordination with stick. On the other hand, out of the variables from the right array, the ones which covered longinality were singled out – Body height and Arm length, circular dimensionality – Circumference of stretched upper arm, Circumference of bent upper arm and Circumference of upper leg, as well as subcutaneous fat tissue – Skin fold of the back.

PROMO – Real-time Prospective Motion Correction in MRI using Image-based Tracking

Science.gov (United States)

White, Nathan; Roddey, Cooper; Shankaranarayanan, Ajit; Han, Eric; Rettmann, Dan; Santos, Juan; Kuperman, Josh; Dale, Anders

2010-01-01

Artifacts caused by patient motion during scanning remain a serious problem in most MRI applications. The prospective motion correction technique attempts to address this problem at its source by keeping the measurement coordinate system fixed with respect to the patient throughout the entire scan process. In this study, a new image-based approach for prospective motion correction is described, which utilizes three orthogonal 2D spiral navigator acquisitions (SP-Navs) along with a flexible image-based tracking method based on the Extended Kalman Filter (EKF) algorithm for online motion measurement. The SP-Nav/EKF framework offers the advantages of image-domain tracking within patient-specific regions-of-interest and reduced sensitivity to off-resonance-induced corruption of rigid-body motion estimates. The performance of the method was tested using offline computer simulations and online in vivo head motion experiments. In vivo validation results covering a broad range of staged head motions indicate a steady-state error of the SP-Nav/EKF motion estimates of less than 10 % of the motion magnitude, even for large compound motions that included rotations over 15 degrees. A preliminary in vivo application in 3D inversion recovery spoiled gradient echo (IR-SPGR) and 3D fast spin echo (FSE) sequences demonstrates the effectiveness of the SP-Nav/EKF framework for correcting 3D rigid-body head motion artifacts prospectively in high-resolution 3D MRI scans. PMID:20027635

22 CFR 94.8 - Interagency coordinating group.

Science.gov (United States)

2010-04-01

... 22 Foreign Relations 1 2010-04-01 2010-04-01 false Interagency coordinating group. 94.8 Section 94... § 94.8 Interagency coordinating group. The U.S. Central Authority shall nominate federal employees and may, from time to time, nominate private citizens to serve on an interagency coordinating group to...

Preservation of perceptual integration improves temporal stability of bimanual coordination in the elderly: an evidence of age-related brain plasticity.

Science.gov (United States)

Blais, Mélody; Martin, Elodie; Albaret, Jean-Michel; Tallet, Jessica

2014-12-15

Despite the apparent age-related decline in perceptual-motor performance, recent studies suggest that the elderly people can improve their reaction time when relevant sensory information are available. However, little is known about which sensory information may improve motor behaviour itself. Using a synchronization task, the present study investigates how visual and/or auditory stimulations could increase accuracy and stability of three bimanual coordination modes produced by elderly and young adults. Neurophysiological activations are recorded with ElectroEncephaloGraphy (EEG) to explore neural mechanisms underlying behavioural effects. Results reveal that the elderly stabilize all coordination modes when auditory or audio-visual stimulations are available, compared to visual stimulation alone. This suggests that auditory stimulations are sufficient to improve temporal stability of rhythmic coordination, even more in the elderly. This behavioural effect is primarily associated with increased attentional and sensorimotor-related neural activations in the elderly but similar perceptual-related activations in elderly and young adults. This suggests that, despite a degradation of attentional and sensorimotor neural processes, perceptual integration of auditory stimulations is preserved in the elderly. These results suggest that perceptual-related brain plasticity is, at least partially, conserved in normal aging. Copyright © 2014 Elsevier B.V. All rights reserved.

Geometrically motivated coordinate system for exploring spacetime dynamics in numerical-relativity simulations using a quasi-Kinnersley tetrad

Science.gov (United States)

Zhang, Fan; Brink, Jeandrew; Szilágyi, Béla; Lovelace, Geoffrey

2012-10-01

We investigate the suitability and properties of a quasi-Kinnersley tetrad and a geometrically motivated coordinate system as tools for quantifying both strong-field and wave-zone effects in numerical relativity (NR) simulations. We fix two of the coordinate degrees of freedom of the metric, namely, the radial and latitudinal coordinates, using the Coulomb potential associated with the quasi-Kinnersley transverse frame. These coordinates are invariants of the spacetime and can be used to unambiguously fix the outstanding spin-boost freedom associated with the quasi-Kinnersley frame (and thus can be used to choose a preferred quasi-Kinnersley tetrad). In the limit of small perturbations about a Kerr spacetime, these geometrically motivated coordinates and quasi-Kinnersley tetrad reduce to Boyer-Lindquist coordinates and the Kinnersley tetrad, irrespective of the simulation gauge choice. We explore the properties of this construction both analytically and numerically, and we gain insights regarding the propagation of radiation described by a super-Poynting vector, further motivating the use of this construction in NR simulations. We also quantify in detail the peeling properties of the chosen tetrad and gauge. We argue that these choices are particularly well-suited for a rapidly converging wave-extraction algorithm as the extraction location approaches infinity, and we explore numerically the extent to which this property remains applicable on the interior of a computational domain. Using a number of additional tests, we verify numerically that the prescription behaves as required in the appropriate limits regardless of simulation gauge; these tests could also serve to benchmark other wave extraction methods. We explore the behavior of the geometrically motivated coordinate system in dynamical binary-black-hole NR mergers; while we obtain no unexpected results, we do find that these coordinates turn out to be useful for visualizing NR simulations (for example, for

Inter-fraction variations in respiratory motion models

Energy Technology Data Exchange (ETDEWEB)

McClelland, J R; Modat, M; Ourselin, S; Hawkes, D J [Centre for Medical Image Computing, University College London (United Kingdom); Hughes, S; Qureshi, A; Ahmad, S; Landau, D B, E-mail: j.mcclelland@cs.ucl.ac.uk [Department of Oncology, Guy' s and St Thomas' s Hospitals NHS Trust, London (United Kingdom)

2011-01-07

Respiratory motion can vary dramatically between the planning stage and the different fractions of radiotherapy treatment. Motion predictions used when constructing the radiotherapy plan may be unsuitable for later fractions of treatment. This paper presents a methodology for constructing patient-specific respiratory motion models and uses these models to evaluate and analyse the inter-fraction variations in the respiratory motion. The internal respiratory motion is determined from the deformable registration of Cine CT data and related to a respiratory surrogate signal derived from 3D skin surface data. Three different models for relating the internal motion to the surrogate signal have been investigated in this work. Data were acquired from six lung cancer patients. Two full datasets were acquired for each patient, one before the course of radiotherapy treatment and one at the end (approximately 6 weeks later). Separate models were built for each dataset. All models could accurately predict the respiratory motion in the same dataset, but had large errors when predicting the motion in the other dataset. Analysis of the inter-fraction variations revealed that most variations were spatially varying base-line shifts, but changes to the anatomy and the motion trajectories were also observed.

Recent achievements in the Hamiltonian treatment of the dynamics and motion of compact binaries in general relativity

International Nuclear Information System (INIS)

Schäfer, Gerhard

2014-01-01

The current knowledge in the post-Newtonian (PN) dynamics and motion of non-spinning and spinning compact binaries will be presented based on the Arnowitt-Deser-Misner Hamiltonian approach to general relativity. The presentation will cover the binary dynamics with non-spinning components up to the 4PN order and for spinning binaries up to the next-to-next-to-leading order in the spin-orbit and spin-spin couplings. Radiation reaction will be treated for both non-spinning and spinning binaries. Explicit analytic expressions for the motion will be given, innermost stable circular orbits will be discussed

Quantum Hamilton mechanics: Hamilton equations of quantum motion, origin of quantum operators, and proof of quantization axiom

International Nuclear Information System (INIS)

Yang, C.-D.

2006-01-01

This paper gives a thorough investigation on formulating and solving quantum problems by extended analytical mechanics that extends canonical variables to complex domain. With this complex extension, we show that quantum mechanics becomes a part of analytical mechanics and hence can be treated integrally with classical mechanics. Complex canonical variables are governed by Hamilton equations of motion, which can be derived naturally from Schroedinger equation. Using complex canonical variables, a formal proof of the quantization axiom p → p = -ih∇, which is the kernel in constructing quantum-mechanical systems, becomes a one-line corollary of Hamilton mechanics. The derivation of quantum operators from Hamilton mechanics is coordinate independent and thus allows us to derive quantum operators directly under any coordinate system without transforming back to Cartesian coordinates. Besides deriving quantum operators, we also show that the various prominent quantum effects, such as quantization, tunneling, atomic shell structure, Aharonov-Bohm effect, and spin, all have the root in Hamilton mechanics and can be described entirely by Hamilton equations of motion

Biomechanics Analysis of Combat Sport (Silat) By Using Motion Capture System

Science.gov (United States)

Zulhilmi Kaharuddin, Muhammad; Badriah Khairu Razak, Siti; Ikram Kushairi, Muhammad; Syawal Abd. Rahman, Mohamed; An, Wee Chang; Ngali, Z.; Siswanto, W. A.; Salleh, S. M.; Yusup, E. M.

2017-01-01

‘Silat’ is a Malay traditional martial art that is practiced in both amateur and in professional levels. The intensity of the motion spurs the scientific research in biomechanics. The main purpose of this abstract is to present the biomechanics method used in the study of ‘silat’. By using the 3D Depth Camera motion capture system, two subjects are to perform ‘Jurus Satu’ in three repetitions each. One subject is set as the benchmark for the research. The videos are captured and its data is processed using the 3D Depth Camera server system in the form of 16 3D body joint coordinates which then will be transformed into displacement, velocity and acceleration components by using Microsoft excel for data calculation and Matlab software for simulation of the body. The translated data obtained serves as an input to differentiate both subjects’ execution of the ‘Jurus Satu’. Nine primary movements with the addition of five secondary movements are observed visually frame by frame from the simulation obtained to get the exact frame that the movement takes place. Further analysis involves the differentiation of both subjects’ execution by referring to the average mean and standard deviation of joints for each parameter stated. The findings provide useful data for joints kinematic parameters as well as to improve the execution of ‘Jurus Satu’ and to exhibit the process of learning a movement that is relatively unknown by the use of a motion capture system.

Geocenter Motion Derived from GNSS and SLR Tracking Data of LEO

Science.gov (United States)

Li, Y. S.; Ning, F. S.; Tseng, K. H.; Tseng, T. P.; Wu, J. M.; Chen, K. L.

2017-12-01

Space geodesy techniques can provide the monitoring data of global variations with high precision and large coverage through the satellites. Geocenter motion (GM) describes the difference of CF (Center of Figure) respect to CM (Center of Mass of the Earth System) due to the re-distribution and deformation of the earth system. Because satellite tracking data between ground stations and satellites orbit around the CM, geocenter motion is related to the realization of the ITRF (International Terrestrial Reference Frame) origin. In this study, GPS (Global Positioning System) observation data of IGS (International GNSS Service) and SLR (Satellite Laser Ranging) tracking data are applied to estimate the coordinates of observing sites on Earth's surface. The GPS observing sites are distributed deliberately and globally by 15° ×15° grids. Meanwhile, two different global ocean tide models are applied here. The model used in ITRF comparison and combination is parameter transformation, which is a mathematical formula allowing to transform the different frames between ITRF and CM system. Following the parameter transformation, the results of geocenter motion can be determined. The FORMOSAT-7/COSMIC-2 (F7C2) mission is a constellation of LEO (Low-Earth-Orbit) satellites, which will be launched in 2018. Besides the observing system for Meteorology, Ionosphere, and Climate, the F7C2 will be equipped with LRR (Laser Ranging Retroreflector). This work is a pilot survey to study the application of LEO SLR data in Taiwan.

VizieR Online Data Catalog: Velocities and proper motions of Galactic Cepheids (Mel'nik+, 2015)

Science.gov (United States)

Mel'Nik, A. M.; Rautiainen, P.; Berdnikov, L. N.; Dambis, A. K.; Rastorguev, A. S.

2015-01-01

For every classical Cepheid we give its designation in the General Catalog of Variable Stars (GCVS) (Samus at al., 2007, Cat. B/gcvs) or in the All Sky Automated Survey (ASAS) (Pojmanski 2002, II/264), its type (see GCVS description), fundamental period PF, intensity-mean V-band magnitude , J2000 equatorial coordinates, Galactic coordinates l and b, and heliocentric distance r. Table 1 also gives the Cepheid line-of-sight velocities Vr (the so-called γ-velocities), their uncertainties e_Vr and the references (1-6) to the sources from which they are taken. The proper motions of Cepheids were adopted from the new reduction of Hipparcos data (ESA 1997, Cat. I/239) by van Leeuwen (2007, Cat. I/311). Table 1 presents proper motions pml and pmb, their uncertainties e_pml and e_pmb and the corresponding Hipparcos catalog number HIP. (1 data file).

A Pursuit Theory Account for the Perception of Common Motion in Motion Parallax.

Science.gov (United States)

Ratzlaff, Michael; Nawrot, Mark

2016-09-01

The visual system uses an extraretinal pursuit eye movement signal to disambiguate the perception of depth from motion parallax. Visual motion in the same direction as the pursuit is perceived nearer in depth while visual motion in the opposite direction as pursuit is perceived farther in depth. This explanation of depth sign applies to either an allocentric frame of reference centered on the fixation point or an egocentric frame of reference centered on the observer. A related problem is that of depth order when two stimuli have a common direction of motion. The first psychophysical study determined whether perception of egocentric depth order is adequately explained by a model employing an allocentric framework, especially when the motion parallax stimuli have common rather than divergent motion. A second study determined whether a reversal in perceived depth order, produced by a reduction in pursuit velocity, is also explained by this model employing this allocentric framework. The results show than an allocentric model can explain both the egocentric perception of depth order with common motion and the perceptual depth order reversal created by a reduction in pursuit velocity. We conclude that an egocentric model is not the only explanation for perceived depth order in these common motion conditions. © The Author(s) 2016.

Kinesthetic deficit in children with developmental coordination disorder.

Science.gov (United States)

Li, Kuan-yi; Su, Wei-jen; Fu, Hsuan-wei; Pickett, Kristen A

2015-03-01

The aim of this study was to measure and compare kinesthetic sensitivity in children with developmental coordination disorder (DCD) and typically developing (TD) children between 6 and 11 years old. 30 children with DCD aged 6 to 11 years (5 in each age group) and 30 TD children participated in the study. Participants placed their forearms on a passive motion apparatus which extended the elbow joint at constant velocities between 0.15 and 1.35°s(-1). Participants were required to concentrate on detection of passive arm motion and press a trigger held in their left hand once they sensed it. The detection time was measured for each trial. The DCD group was significantly less sensitive in detection of passive motion than TD children. Further analysis of individual age groups revealed that kinesthetic sensitivity was worse in DCD than TD children for age groups beyond six years of age. Our findings suggested that individual with DCD lag behind their TD counterparts in kinesthetic sensitivity. Between the ages of 7 and 11 years the difference between groups is quantifiable and significant with 11 year old children with DCD performing similar to 7 year old TD children. Copyright © 2014 Elsevier Ltd. All rights reserved.

Cervical motion testing: methodology and clinical implications.

Science.gov (United States)

Prushansky, Tamara; Dvir, Zeevi

2008-09-01

Measurement of cervical motion (CM) is probably the most commonly applied functional outcome measure in assessing the status of patients with cervical pathology. In general terms, CM refers to motion of the head relative to the trunk as well as conjunct motions within the cervical spine. Multiple techniques and instruments have been used for assessing CM. These were associated with a wide variety of parameters relating to accuracy, reproducibility, and validity. Modern measurement systems enable recording, processing, and documentation of CM with a high degree of precision. Cervical motion measures provide substantial information regarding the severity of motion limitation and level of effort in cervically involved patients. They may also be used for following up performance during and after conservative or invasive interventions.

Motion camouflage in three dimensions

OpenAIRE

Reddy, P. V.; Justh, E. W.; Krishnaprasad, P. S.

2006-01-01

We formulate and analyze a three-dimensional model of motion camouflage, a stealth strategy observed in nature. A high-gain feedback law for motion camouflage is formulated in which the pursuer and evader trajectories are described using natural Frenet frames (or relatively parallel adapted frames), and the corresponding natural curvatures serve as controls. The biological plausibility of the feedback law is discussed, as is its connection to missile guidance. Simulations illustrating motion ...

Transient Severe Motion Artifact Related to Gadoxetate Disodium-Enhanced Liver MRI: Frequency and Risk Evaluation at a German Institution.

Science.gov (United States)

Well, Lennart; Rausch, Vanessa Hanna; Adam, Gerhard; Henes, Frank Oliver; Bannas, Peter

2017-07-01

Purpose  Varying frequencies (5 - 18 %) of contrast-related transient severe motion (TSM) imaging artifacts during gadoxetate disodium-enhanced arterial phase liver MRI have been reported. Since previous reports originated from the United States and Japan, we aimed to determine the frequency of TSM at a German institution and to correlate it with potential risk factors and previously published results. Materials and Methods  Two age- and sex-matched groups were retrospectively selected (gadoxetate disodium n = 89; gadobenate dimeglumine n = 89) from dynamic contrast-enhanced MRI examinations in a single center. Respiratory motion-related artifacts in non-enhanced and dynamic phases were assessed independently by two readers blinded to contrast agents on a 4-point scale. Scores of ≥ 3 were considered as severe motion artifacts. Severe motion artifacts in arterial phases were considered as TSM if scores in all other phases were risk factors for TSM were evaluated via logistic regression analysis. Results  For gadoxetate disodium, the mean score for respiratory motion artifacts was significantly higher in the arterial phase (2.2 ± 0.9) compared to all other phases (1.6 ± 0.7) (p risk factors (all p > 0.05). Conclusion  We revealed a high frequency of TSM after injection of gadoxetate disodium at a German institution, substantiating the importance of a diagnosis-limiting phenomenon that so far has only been reported from the United States and Japan. In accordance with previous studies, we did not identify associated risk factors for TSM. Key Points:   · Gadoxetate disodium causes TSM in a relevant number of patients.. · The frequency of TSM is similar between the USA, Japan and Germany.. · To date, no validated risk factors for TSM could be identified.. Citation Format · Well L, Rausch VH, Adam G et al. Transient Severe Motion Artifact Related to Gadoxetate Disodium-Enhanced Liver MRI: Frequency and Risk Evaluation at a

Metadata-Assisted Global Motion Estimation for Medium-Altitude Unmanned Aerial Vehicle Video Applications

Directory of Open Access Journals (Sweden)

Hongguang Li

2015-09-01

Full Text Available Global motion estimation (GME is a key technology in unmanned aerial vehicle remote sensing (UAVRS. However, when a UAV’s motion and behavior change significantly or the image information is not rich, traditional image-based methods for GME often perform poorly. Introducing bottom metadata can improve precision in a large-scale motion condition and reduce the dependence on unreliable image information. GME is divided into coarse and residual GME through coordinate transformation and based on the study hypotheses. In coarse GME, an auxiliary image is built to convert image matching from a wide baseline condition to a narrow baseline one. In residual GME, a novel information and contrast feature detection algorithm is proposed for big-block matching to maximize the use of reliable image information and ensure that the contents of interest are well estimated. Additionally, an image motion monitor is designed to select the appropriate processing strategy by monitoring the motion scales of translation, rotation, and zoom. A medium-altitude UAV is employed to collect three types of large-scale motion datasets. Peak signal to noise ratio (PSNR and motion scale are computed. This study’s result is encouraging and applicable to other medium- or high-altitude UAVs with a similar system structure.

Monrelativistic particle in a magnetic field in two-dimensional Lobachevsky space, the cylindrical coordinates and the Poincare half-plane

International Nuclear Information System (INIS)

Ovsiyu, E.M.

2012-01-01

Exact solutions of the Schrodinger equation in the two-dimensional Riemannian space of negative curvature, the hyperbolic Lobachevsky plane, in the presence of an external magnetic field, which is an analog of a uniform magnetic field in the Minkowski space, are constructed. The description uses the cylindrical and quasi-Cartesian coordinates. The quasi-Cartesian coordinates determine the Poincare half-plane. In the both coordinate systems, the Schrodinger equation is solved exactly, the wave functions are constructed. A generalized formula for energy levels is found, which describes the quantized motion of a particle in a magnetic field in the Lobachevsky plane. (authors)

Branner-Hubbard Motions and attracting dynamics

DEFF Research Database (Denmark)

Petersen, Carsten Lunde; Tan, Lei

2006-01-01

We introduce a new notion of attracting dynamics, which is related to polynomial-like mappings. Also we review the Branner-Hubbard Motion and study its action on attracting dynamics.......We introduce a new notion of attracting dynamics, which is related to polynomial-like mappings. Also we review the Branner-Hubbard Motion and study its action on attracting dynamics....

Branner-Hubbard motions and attracting dynamics

DEFF Research Database (Denmark)

Petersen, Carsten Lunde; Tan, Lei

We introduce the new notion an aatracting dynamics, which is related to polynomial-likke mappings. Also we review the Branner-Hubbard motion and study its action on attracting dynamics.......We introduce the new notion an aatracting dynamics, which is related to polynomial-likke mappings. Also we review the Branner-Hubbard motion and study its action on attracting dynamics....

A simplified generator coordinate treatment with analytical projected-BCS solutions for isovector pairing collective motions

International Nuclear Information System (INIS)

Kyotoku, M.; Chen, H.T.

1979-01-01

Analytical expressions for the projected-BCS energies and reaction transition rates among the isovector pairing collective states are obtained by the recognition of symmetry properties in a class of BCS wave functions. As a consequence, a simplified generator coordinate treatment is suggested [pt

Executive functions, visual-motor coordination, physical fitness and academic achievement: Longitudinal relations in typically developing children.

Science.gov (United States)

Oberer, Nicole; Gashaj, Venera; Roebers, Claudia M

2018-04-01

The present longitudinal study included different school readiness factors measured in kindergarten with the aim to predict later academic achievement in second grade. Based on data of N = 134 children, the predictive power of executive functions, visual-motor coordination and physical fitness on later academic achievement was estimated using a latent variable approach. By entering all three predictors simultaneously into the model to predict later academic achievement, significant effects of executive functions and visual-motor coordination on later academic achievement were found. The influence of physical fitness was found to be substantial but indirect via executive functions. The cognitive stimulation hypothesis as well as the automaticity hypothesis are discussed as an explanation for the reported relations. Copyright © 2018 The Authors. Published by Elsevier B.V. All rights reserved.

SCALABLE PHOTOGRAMMETRIC MOTION CAPTURE SYSTEM “MOSCA”: DEVELOPMENT AND APPLICATION

Directory of Open Access Journals (Sweden)

V. A. Knyaz

2015-05-01

Full Text Available Wide variety of applications (from industrial to entertainment has a need for reliable and accurate 3D information about motion of an object and its parts. Very often the process of movement is rather fast as in cases of vehicle movement, sport biomechanics, animation of cartoon characters. Motion capture systems based on different physical principles are used for these purposes. The great potential for obtaining high accuracy and high degree of automation has vision-based system due to progress in image processing and analysis. Scalable inexpensive motion capture system is developed as a convenient and flexible tool for solving various tasks requiring 3D motion analysis. It is based on photogrammetric techniques of 3D measurements and provides high speed image acquisition, high accuracy of 3D measurements and highly automated processing of captured data. Depending on the application the system can be easily modified for different working areas from 100 mm to 10 m. The developed motion capture system uses from 2 to 4 technical vision cameras for video sequences of object motion acquisition. All cameras work in synchronization mode at frame rate up to 100 frames per second under the control of personal computer providing the possibility for accurate calculation of 3D coordinates of interest points. The system was used for a set of different applications fields and demonstrated high accuracy and high level of automation.

Photon motion in Kerr-de Sitter spacetimes

Energy Technology Data Exchange (ETDEWEB)

Charbulak, Daniel; Stuchlik, Zdenek [Silesian University in Opava, Institute of Physics and Research Centre of Theoretical Physics and Astrophysics, Faculty of Philosophy and Science, Opava (Czech Republic)

2017-12-15

We study the general motion of photons in the Kerr-de Sitter black-hole and naked singularity spacetimes. The motion is governed by the impact parameters X, related to the axial symmetry of the spacetime, and q, related to its hidden symmetry. Appropriate 'effective potentials' governing the latitudinal and radial motion are introduced and their behavior is examined by the 'Chinese boxes' technique giving regions allowed for the motion in terms of the impact parameters. Restrictions on the impact parameters X and q are established in dependence on the spacetime parameters M, Λ, a. The motion can be of orbital type (crossing the equatorial plane, q > 0) and vortical type (tied above or below the equatorial plane, q < 0). It is shown that for negative values of q, the reality conditions imposed on the latitudinal motion yield stronger constraints on the parameter X than that following from the reality condition of the radial motion, excluding the existence of vortical motion of constant radius. The properties of the spherical photon orbits of the orbital type are determined and used along with the properties of the effective potentials as criteria of classification of the KdS spacetimes according to the properties of the motion of the photon. (orig.)

A reduced-dimensionality approach to uncovering dyadic modes of body motion in conversations.

Science.gov (United States)

Gaziv, Guy; Noy, Lior; Liron, Yuvalal; Alon, Uri

2017-01-01

Face-to-face conversations are central to human communication and a fascinating example of joint action. Beyond verbal content, one of the primary ways in which information is conveyed in conversations is body language. Body motion in natural conversations has been difficult to study precisely due to the large number of coordinates at play. There is need for fresh approaches to analyze and understand the data, in order to ask whether dyads show basic building blocks of coupled motion. Here we present a method for analyzing body motion during joint action using depth-sensing cameras, and use it to analyze a sample of scientific conversations. Our method consists of three steps: defining modes of body motion of individual participants, defining dyadic modes made of combinations of these individual modes, and lastly defining motion motifs as dyadic modes that occur significantly more often than expected given the single-person motion statistics. As a proof-of-concept, we analyze the motion of 12 dyads of scientists measured using two Microsoft Kinect cameras. In our sample, we find that out of many possible modes, only two were motion motifs: synchronized parallel torso motion in which the participants swayed from side to side in sync, and still segments where neither person moved. We find evidence of dyad individuality in the use of motion modes. For a randomly selected subset of 5 dyads, this individuality was maintained for at least 6 months. The present approach to simplify complex motion data and to define motion motifs may be used to understand other joint tasks and interactions. The analysis tools developed here and the motion dataset are publicly available.

29 CFR 1921.5 - Motions and requests.

Science.gov (United States)

2010-07-01

... 29 Labor 7 2010-07-01 2010-07-01 false Motions and requests. 1921.5 Section 1921.5 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR... WORKERS' COMPENSATION ACT Prehearing Procedures § 1921.5 Motions and requests. Motions or requests shall...

Affine Transform to Reform Pixel Coordinates of EOG Signals for Controlling Robot Manipulators Using Gaze Motions

Directory of Open Access Journals (Sweden)

Muhammad Ilhamdi Rusydi

2014-06-01

Full Text Available Biosignals will play an important role in building communication between machines and humans. One of the types of biosignals that is widely used in neuroscience are electrooculography (EOG signals. An EOG has a linear relationship with eye movement displacement. Experiments were performed to construct a gaze motion tracking method indicated by robot manipulator movements. Three operators looked at 24 target points displayed on a monitor that was 40 cm in front of them. Two channels (Ch1 and Ch2 produced EOG signals for every single eye movement. These signals were converted to pixel units by using the linear relationship between EOG signals and gaze motion distances. The conversion outcomes were actual pixel locations. An affine transform method is proposed to determine the shift of actual pixels to target pixels. This method consisted of sequences of five geometry processes, which are translation-1, rotation, translation-2, shear and dilatation. The accuracy was approximately 0.86° ± 0.67° in the horizontal direction and 0.54° ± 0.34° in the vertical. This system successfully tracked the gaze motions not only in direction, but also in distance. Using this system, three operators could operate a robot manipulator to point at some targets. This result shows that the method is reliable in building communication between humans and machines using EOGs.

Affine transform to reform pixel coordinates of EOG signals for controlling robot manipulators using gaze motions.

Science.gov (United States)

Rusydi, Muhammad Ilhamdi; Sasaki, Minoru; Ito, Satoshi

2014-06-10

Biosignals will play an important role in building communication between machines and humans. One of the types of biosignals that is widely used in neuroscience are electrooculography (EOG) signals. An EOG has a linear relationship with eye movement displacement. Experiments were performed to construct a gaze motion tracking method indicated by robot manipulator movements. Three operators looked at 24 target points displayed on a monitor that was 40 cm in front of them. Two channels (Ch1 and Ch2) produced EOG signals for every single eye movement. These signals were converted to pixel units by using the linear relationship between EOG signals and gaze motion distances. The conversion outcomes were actual pixel locations. An affine transform method is proposed to determine the shift of actual pixels to target pixels. This method consisted of sequences of five geometry processes, which are translation-1, rotation, translation-2, shear and dilatation. The accuracy was approximately 0.86° ± 0.67° in the horizontal direction and 0.54° ± 0.34° in the vertical. This system successfully tracked the gaze motions not only in direction, but also in distance. Using this system, three operators could operate a robot manipulator to point at some targets. This result shows that the method is reliable in building communication between humans and machines using EOGs.

Adaptive Changes in Sensorimotor Coordination and Motion Sickness Following Repeated Exposures to Virtual Environments

Science.gov (United States)

Harm, D. L.; Taylor, L. C.; Bloomberg, J. J.

2007-01-01

Virtual environments offer unique training opportunities, particularly for training astronauts and preadapting them to the novel sensory conditions of microgravity. Two unresolved human factors issues in virtual reality (VR) systems are: 1) potential "cybersickness", and 2) maladaptive sensorimotor performance following exposure to VR systems. Interestingly, these aftereffects are often quite similar to adaptive sensorimotor responses observed in astronauts during and/or following space flight. Initial interpretation of novel sensory information may be inappropriate and result in perceptual errors. Active exploratory behavior in a new environment, with resulting feedback and the formation of new associations between sensory inputs and response outputs, promotes appropriate perception and motor control in the new environment. Thus, people adapt to consistent, sustained alterations of sensory input such as those produced by microgravity, unilateral labyrinthectomy and experimentally produced stimulus rearrangements. The purpose of this research was to compare disturbances in sensorimotor coordination produced by dome and head-mounted virtual environment displays and to examine the effects of exposure duration, and repeated exposures to VR systems. The first study examined disturbances in balance control, and the second study examined disturbances in eye-head-hand (EHH) and eye-head coordination.

Is Nubia plate rigid? A geodetic study of the relative motion of different cratonic areas within Africa.

Science.gov (United States)

Njoroge, M. W.; Malservisi, R.; Hugentobler, U.; Mokhtari, M.; Voytenko, D.

2014-12-01

Plate rigidity is one of the main paradigms of plate tectonics and a fundamental assumption in the definition of a global reference frame as ITRF. Although still far for optimal, the increased GPS instrumentation of the African region can allow us to understand how rigid one of the major plate can be. The presence of diffused band of seismicity, the Cameroon volcanic line, Pan African Kalahari orogenic belt and East Africa Rift suggest the possibility of relative motion among the different regions within the Nubia. The study focuses on the rigidity of Nubia plate. We divide the plate into three regions: Western (West Africa craton plus Nigeria), Central (approximately the region of the Congo craton) and Southern (Kalahari craton plus South Africa) and we utilize Euler Vector formulation to study internal rigidity and eventual relative motion. Developing five different reference frames with different combinations of the 3 regions, we try to understand the presence of the relative motion between the 3 cratons thus the stability of the Nubia plate as a whole. All available GPS stations from the regions are used separately or combined in creation of the reference frames. We utilize continuous stations with at least 2.5 years of data between 1994 and 2014. Given the small relative velocity, it is important to eliminate eventual biases in the analysis and to have a good estimation in the uncertainties of the observed velocities. For this reason we perform our analysis using both Bernese and Gipsy-oasis codes to generate time series for each station. Velocities and relative uncertainties are analyzed using the Allan variance of rate technique, taking in account for colored noise. An analysis of the color of the noise as function of latitude and climatic region is also performed to each time series. Preliminary results indicate a slight counter clockwise motion of West Africa craton with respect to South Africa Kalahari, and South Africa Kalahari-Congo Cratons. In addition

Giving the force direction: Analysis of speed skater push off forces with respect to an inertial coordinate system

OpenAIRE

van der Kruk, E.; van der Helm, F.C.T.; Schwab, A.L.; Veeger, H.E.J.

2016-01-01

Pushoff in speed skating requires an extensive motion strategy. During speed skating the skater continuously changes the lean and steering angle of the skate and therewith the direction of push-off, The forces in an inertial coordinate system can give insight into what amount of the push-off force is directed into the forward motion. In this paper we present the preliminary results of a study on the global forces in speed skating. From a mechanical viewpoint, increasing the lean angle of the ...

Application of the adiabatic self-consistent collective coordinate method to a solvable model of prolate-oblate shape coexistence

International Nuclear Information System (INIS)

Kobayasi, Masato; Matsuyanagi, Kenichi; Nakatsukasa, Takashi; Matsuo, Masayuki

2003-01-01

The adiabatic self-consistent collective coordinate method is applied to an exactly solvable multi-O(4) model that is designed to describe nuclear shape coexistence phenomena. The collective mass and dynamics of large amplitude collective motion in this model system are analyzed, and it is shown that the method yields a faithful description of tunneling motion through a barrier between the prolate and oblate local minima in the collective potential. The emergence of the doublet pattern is clearly described. (author)

Measurement and Quantification of Gross Human Shoulder Motion

Directory of Open Access Journals (Sweden)

Jeremy T. Newkirk

2013-01-01

Full Text Available The shoulder girdle plays an important role in the large pointing workspace that humans enjoy. The goal of this work was to characterize the human shoulder girdle motion in relation to the arm. The overall motion of the human shoulder girdle was characterized based on motion studies completed on test subjects during voluntary (natural/unforced motion. The collected data from the experiments were used to develop surface fit equations that represent the position and orientation of the glenohumeral joint for a given humeral pointing direction. These equations completely quantify gross human shoulder girdle motion relative to the humerus. The equations are presented along with goodness-of-fit results that indicate the equations well approximate the motion of the human glenohumeral joint. This is the first time the motion has been quantified for the entire workspace, and the equations provide a reference against which to compare future work.

A method of Moessbauer Fourier spectroscopy for determination of the biopolimer coordinate correlation functions

International Nuclear Information System (INIS)

Basovets, S.K.; Krupyanskij, Yu.F.; Kurinov, I.V.; Suzdalev, I.P.; Goldanskij, V.I.; Uporov, I.V.; Shaitan, K.V.; Rubin, A.B.

1988-01-01

A method of Moessbauer Fourier spectroscopy is developed to determine the correlation function of coordinates of a macromolecular system. The method does not require the use of an a priori dynamic model. The application of the method to the analysis of RSMR data for human serum albumin has demonstrated considerable changes in the dynamic behavior of the protein globule when the temperature is changed from 270 to 310 K. The main conclusions of the present work is the simultaneous observation of low-frequency (τ≥10 -9 sec) and high-frequency (τ -9 sec) large-scaled motions, that is the two-humped distribution of correlation times of protein motions. (orig.)

Daple Coordinates Planar Polarized Microtubule Dynamics in Ependymal Cells and Contributes to Hydrocephalus

Directory of Open Access Journals (Sweden)

Maki Takagishi

2017-07-01

Full Text Available Motile cilia in ependymal cells, which line the cerebral ventricles, exhibit a coordinated beating motion that drives directional cerebrospinal fluid (CSF flow and guides neuroblast migration. At the apical cortex of these multi-ciliated cells, asymmetric localization of planar cell polarity (PCP proteins is required for the planar polarization of microtubule dynamics, which coordinates cilia orientation. Daple is a disheveled-associating protein that controls the non-canonical Wnt signaling pathway and cell motility. Here, we show that Daple-deficient mice present hydrocephalus and their ependymal cilia lack coordinated orientation. Daple regulates microtubule dynamics at the anterior side of ependymal cells, which in turn orients the cilial basal bodies required for the directional cerebrospinal fluid flow. These results demonstrate an important role for Daple in planar polarity in motile cilia and provide a framework for understanding the mechanisms and functions of planar polarization in the ependymal cells.

The effects of complex exercise on shoulder range of motion and pain for women with breast cancer-related lymphedema: a single-blind, randomized controlled trial.

Science.gov (United States)

Park, Jin-Hyuck

2017-07-01

This study was to investigate the effects of complex exercise on shoulder range of motion and pain for women with breast cancer-related lymphedema. 69 women participated in this study and then they were randomly allocated to complex exercise group (n = 35) or the conventional decongestive therapy group (n = 34). All subjects received 8 sessions for 4 weeks. To identify the effects on shoulder range of motion and pain, goniometer and visual analog scale were used, respectively. The outcome measurements were performed before and after the 4 week intervention. After 4 weeks, complex exercise group had greater improvements in shoulder range of motion and pain compared with the conventional decongestive therapy group (p women with breast cancer-related lymphedema. Complex exercise would be useful to improve shoulder range of motion and pain of the women with breast cancer-related lymphedema.

Auditory Motion Elicits a Visual Motion Aftereffect.

Science.gov (United States)

Berger, Christopher C; Ehrsson, H Henrik

2016-01-01

The visual motion aftereffect is a visual illusion in which exposure to continuous motion in one direction leads to a subsequent illusion of visual motion in the opposite direction. Previous findings have been mixed with regard to whether this visual illusion can be induced cross-modally by auditory stimuli. Based on research on multisensory perception demonstrating the profound influence auditory perception can have on the interpretation and perceived motion of visual stimuli, we hypothesized that exposure to auditory stimuli with strong directional motion cues should induce a visual motion aftereffect. Here, we demonstrate that horizontally moving auditory stimuli induced a significant visual motion aftereffect-an effect that was driven primarily by a change in visual motion perception following exposure to leftward moving auditory stimuli. This finding is consistent with the notion that visual and auditory motion perception rely on at least partially overlapping neural substrates.

Auditory Motion Elicits a Visual Motion Aftereffect

Directory of Open Access Journals (Sweden)

Christopher C. Berger

2016-12-01

Full Text Available The visual motion aftereffect is a visual illusion in which exposure to continuous motion in one direction leads to a subsequent illusion of visual motion in the opposite direction. Previous findings have been mixed with regard to whether this visual illusion can be induced cross-modally by auditory stimuli. Based on research on multisensory perception demonstrating the profound influence auditory perception can have on the interpretation and perceived motion of visual stimuli, we hypothesized that exposure to auditory stimuli with strong directional motion cues should induce a visual motion aftereffect. Here, we demonstrate that horizontally moving auditory stimuli induced a significant visual motion aftereffect—an effect that was driven primarily by a change in visual motion perception following exposure to leftward moving auditory stimuli. This finding is consistent with the notion that visual and auditory motion perception rely on at least partially overlapping neural substrates.

Stochastic calculus for fractional Brownian motion and related processes

CERN Document Server

Mishura, Yuliya S

2008-01-01

The theory of fractional Brownian motion and other long-memory processes are addressed in this volume. Interesting topics for PhD students and specialists in probability theory, stochastic analysis and financial mathematics demonstrate the modern level of this field. Among these are results about Levy characterization of fractional Brownian motion, maximal moment inequalities for Wiener integrals including the values 0

Motion Of Bodies And Its Stability In The General Relativity Theory

International Nuclear Information System (INIS)

Ryabushko, Anton P.; Zhur, Tatyana A.; Nemanova, Inna T.

2010-01-01

This paper reviews the works by the Belarusian school investigators on relativistic motion and its stability for a system of bodies, each of which may have its own rotation, charge, and magnetic field of the dipole type. The corresponding Lagrangian and conservation laws are derived, several secular effects are predicted. For motion of bodies in the medium the secular effect of the periastron reverse shift is predicted as compared to the Mercury perihelion shift. The cause for the Pioneer anomaly is explained.

Algorithmic Issues in Modeling Motion

DEFF Research Database (Denmark)

Agarwal, P. K; Guibas, L. J; Edelsbrunner, H.

2003-01-01

This article is a survey of research areas in which motion plays a pivotal role. The aim of the article is to review current approaches to modeling motion together with related data structures and algorithms, and to summarize the challenges that lie ahead in producing a more unified theory of mot...

Analysis of the Motion Control Methods for Stratospheric Balloon-Borne Gondola Platform

International Nuclear Information System (INIS)

Wang, H H; Yuan, Z H; Wu, J

2006-01-01

At present, gondola platform is one of the stratospheric balloon-borne platforms being in research focus at home and overseas. Comparing to other stratospheric balloon-borne platforms, such as airship platform, gondola platform has advantages of higher stability, rapid in motion regulation and lower energy cost but disadvantages of less supporting capacity and be incapable of fixation. While all platforms have the same goal of keeping them at accurate angle and right pose for the requirements of instruments and objects installed in the platforms, when platforms rotate round the ground level perpendicular. That is accomplishing motion control. But, platform control system has factors of low damper, excessive and uncertain disturbances by the reason of its being hung over balloon in the air, it is hard to achieve the desired control precision because platform is ease to deviate its benchmark motion. Thus, in the controlling procedure in order to get higher precision, it is crucial to perceive the platform's swing synchronously and rapidly, and restrain the influence of disturbances effectively, keep the platform's pose steadily. Furthermore, while the platform in the air regard control center in the ground as reference object, it is ultimate to select a appropriate reference frame and work out the coordinates and implement the adjustment by the PC104 controller. This paper introduces the methods of the motion control based on stratospheric balloon-borne gondola platform. Firstly, this paper compares the characteristic of the flywheel and CMG and specifies the key methods of obtaining two significant states which are 'orientation stability' state and 'orientation tracking' state for platform motion control procedure using CMG as the control actuator. These two states reduce the deviation amplitude of rotation and swing of gondola's motion relative to original motion due to stratospheric intense atmosphere disturbance. We define it as the first procedure. In next

Analysis of the Motion Control Methods for Stratospheric Balloon-Borne Gondola Platform

Science.gov (United States)

Wang, H. H.; Yuan, Z. H.; Wu, J.

2006-10-01

At present, gondola platform is one of the stratospheric balloon-borne platforms being in research focus at home and overseas. Comparing to other stratospheric balloon-borne platforms, such as airship platform, gondola platform has advantages of higher stability, rapid in motion regulation and lower energy cost but disadvantages of less supporting capacity and be incapable of fixation. While all platforms have the same goal of keeping them at accurate angle and right pose for the requirements of instruments and objects installed in the platforms, when platforms rotate round the ground level perpendicular. That is accomplishing motion control. But, platform control system has factors of low damper, excessive and uncertain disturbances by the reason of its being hung over balloon in the air, it is hard to achieve the desired control precision because platform is ease to deviate its benchmark motion. Thus, in the controlling procedure in order to get higher precision, it is crucial to perceive the platform's swing synchronously and rapidly, and restrain the influence of disturbances effectively, keep the platform's pose steadily. Furthermore, while the platform in the air regard control center in the ground as reference object, it is ultimate to select a appropriate reference frame and work out the coordinates and implement the adjustment by the PC104 controller. This paper introduces the methods of the motion control based on stratospheric balloon-borne gondola platform. Firstly, this paper compares the characteristic of the flywheel and CMG and specifies the key methods of obtaining two significant states which are 'orientation stability' state and 'orientation tracking' state for platform motion control procedure using CMG as the control actuator. These two states reduce the deviation amplitude of rotation and swing of gondola's motion relative to original motion due to stratospheric intense atmosphere disturbance. We define it as the first procedure. In next

Molecular Motion in Polymers: Mechanical Behavior of Polymers Near the Glass-Rubber Transition Temperature.

Science.gov (United States)

Sperling, L. H.

1982-01-01

The temperature at which the onset of coordinated segmental motion begins is called the glass-rubber transition temperature (Tg). Natural rubber at room temperature is a good example of a material above its Tg. Describes an experiment examining the response of a typical polymer to temperature variations above and below Tg. (Author/JN)

Conserved linear dynamics of single-molecule Brownian motion

KAUST Repository

Serag, Maged F.

2017-06-06

Macromolecular diffusion in homogeneous fluid at length scales greater than the size of the molecule is regarded as a random process. The mean-squared displacement (MSD) of molecules in this regime increases linearly with time. Here we show that non-random motion of DNA molecules in this regime that is undetectable by the MSD analysis can be quantified by characterizing the molecular motion relative to a latticed frame of reference. Our lattice occupancy analysis reveals unexpected sub-modes of motion of DNA that deviate from expected random motion in the linear, diffusive regime. We demonstrate that a subtle interplay between these sub-modes causes the overall diffusive motion of DNA to appear to conform to the linear regime. Our results show that apparently random motion of macromolecules could be governed by non-random dynamics that are detectable only by their relative motion. Our analytical approach should advance broad understanding of diffusion processes of fundamental relevance.

Conserved linear dynamics of single-molecule Brownian motion

Science.gov (United States)

Serag, Maged F.; Habuchi, Satoshi

2017-06-01

Macromolecular diffusion in homogeneous fluid at length scales greater than the size of the molecule is regarded as a random process. The mean-squared displacement (MSD) of molecules in this regime increases linearly with time. Here we show that non-random motion of DNA molecules in this regime that is undetectable by the MSD analysis can be quantified by characterizing the molecular motion relative to a latticed frame of reference. Our lattice occupancy analysis reveals unexpected sub-modes of motion of DNA that deviate from expected random motion in the linear, diffusive regime. We demonstrate that a subtle interplay between these sub-modes causes the overall diffusive motion of DNA to appear to conform to the linear regime. Our results show that apparently random motion of macromolecules could be governed by non-random dynamics that are detectable only by their relative motion. Our analytical approach should advance broad understanding of diffusion processes of fundamental relevance.

Conserved linear dynamics of single-molecule Brownian motion

KAUST Repository

Serag, Maged F.; Habuchi, Satoshi

2017-01-01

Macromolecular diffusion in homogeneous fluid at length scales greater than the size of the molecule is regarded as a random process. The mean-squared displacement (MSD) of molecules in this regime increases linearly with time. Here we show that non-random motion of DNA molecules in this regime that is undetectable by the MSD analysis can be quantified by characterizing the molecular motion relative to a latticed frame of reference. Our lattice occupancy analysis reveals unexpected sub-modes of motion of DNA that deviate from expected random motion in the linear, diffusive regime. We demonstrate that a subtle interplay between these sub-modes causes the overall diffusive motion of DNA to appear to conform to the linear regime. Our results show that apparently random motion of macromolecules could be governed by non-random dynamics that are detectable only by their relative motion. Our analytical approach should advance broad understanding of diffusion processes of fundamental relevance.

An encoder for the measurement of relative motions between two objects

International Nuclear Information System (INIS)

Saro, M.

1995-01-01

The motion encoder is composed of a measuring rule, mounted on one of the object, which bears at least two tracks (X, Y) with multiple simple marks distributed following a similar pattern on the two tracks, and at least one specific mark (each mark limit is defining a step variation on the rule), and at least two mark readers, mounted on the second object, each one associated to a track. Data processing means are used to estimate distance and motion direction. Application to robotics and metrology

Equations of motion according to the asymptotic post-Newtonian scheme for general relativity in the harmonic gauge

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Arminjon, Mayeul

2005-10-01

The asymptotic scheme of post-Newtonian approximation defined for general relativity in the harmonic gauge by Futamase & Schutz (1983) is based on a family of initial data for the matter fields of a perfect fluid and for the initial metric, defining a family of weakly self-gravitating systems. We show that Weinberg’s (1972) expansion of the metric and his general expansion of the energy-momentum tensor T, as well as his expanded equations for the gravitational field and his general form of the expanded dynamical equations, apply naturally to this family. Then, following the asymptotic scheme, we derive the explicit form of the expansion of T for a perfect fluid, and the expanded fluid-dynamical equations. (These differ from those written by Weinberg.) By integrating these equations in the domain occupied by a body, we obtain a general form of the translational equations of motion for a 1PN perfect-fluid system in general relativity. To put them into a tractable form, we use an asymptotic framework for the separation parameter η, by defining a family of well-separated 1PN systems. We calculate all terms in the equations of motion up to the order η3 included. To calculate the 1PN correction part, we assume that the Newtonian motion of each body is a rigid one, and that the family is quasispherical, in the sense that in all bodies the inertia tensor comes close to being spherical as η→0. Apart from corrections that cancel for exact spherical symmetry, there is in the final equations of motion one additional term, as compared with the Lorentz-Droste (Einstein-Infeld-Hoffmann) acceleration. This term depends on the spin of the body and on its internal structure.

Dose/volume–response relations for rectal morbidity using planned and simulated motion-inclusive dose distributions

International Nuclear Information System (INIS)

Thor, Maria; Apte, Aditya; Deasy, Joseph O.; Karlsdóttir, Àsa; Moiseenko, Vitali; Liu, Mitchell; Muren, Ludvig Paul

2013-01-01

Background and purpose: Many dose-limiting normal tissues in radiotherapy (RT) display considerable internal motion between fractions over a course of treatment, potentially reducing the appropriateness of using planned dose distributions to predict morbidity. Accounting explicitly for rectal motion could improve the predictive power of modelling rectal morbidity. To test this, we simulated the effect of motion in two cohorts. Materials and methods: The included patients (232 and 159 cases) received RT for prostate cancer to 70 and 74 Gy. Motion-inclusive dose distributions were introduced as simulations of random or systematic motion to the planned dose distributions. Six rectal morbidity endpoints were analysed. A probit model using the QUANTEC recommended parameters was also applied to the cohorts. Results: The differences in associations using the planned over the motion-inclusive dose distributions were modest. Statistically significant associations were obtained with four of the endpoints, mainly at high doses (55–70 Gy), using both the planned and the motion-inclusive dose distributions, primarily when simulating random motion. The strongest associations were observed for GI toxicity and rectal bleeding (Rs = 0.12–0.21; Rs = 0.11–0.20). Applying the probit model, significant associations were found for tenesmus and rectal bleeding (Rs = 0.13, p = 0.02). Conclusion: Equally strong associations with rectal morbidity were observed at high doses (>55 Gy), for the planned and the simulated dose distributions including in particular random rectal motion. Future studies should explore patient-specific descriptions of rectal motion to achieve improved predictive power

Coordinating Group report

International Nuclear Information System (INIS)

1994-01-01

In December 1992, western governors and four federal agencies established a Federal Advisory Committee to Develop On-site Innovative Technologies for Environmental Restoration and Waste Management (the DOIT Committee). The purpose of the Committee is to advise the federal government on ways to improve waste cleanup technology development and the cleanup of federal sites in the West. The Committee directed in January 1993 that information be collected from a wide range of potential stakeholders and that innovative technology candidate projects be identified, organized, set in motion, and evaluated to test new partnerships, regulatory approaches, and technologies which will lead to improve site cleanup. Five working groups were organized, one to develop broad project selection and evaluation criteria and four to focus on specific contaminant problems. A Coordinating Group comprised of working group spokesmen and federal and state representatives, was set up to plan and organize the routine functioning of these working groups. The working groups were charged with defining particular contaminant problems; identifying shortcomings in technology development, stakeholder involvement, regulatory review, and commercialization which impede the resolution of these problems; and identifying candidate sites or technologies which could serve as regional innovative demonstration projects to test new approaches to overcome the shortcomings. This report from the Coordinating Group to the DOIT Committee highlights the key findings and opportunities uncovered by these fact-finding working groups. It provides a basis from which recommendations from the DOIT Committee to the federal government can be made. It also includes observations from two public roundtables, one on commercialization and another on regulatory and institutional barriers impeding technology development and cleanup

[Binocular coordination during reading].

Science.gov (United States)

Bassou, L; Granié, M; Pugh, A K; Morucci, J P

1992-01-01

Is there an effect on binocular coordination during reading of oculomotor imbalance (heterophoria, strabismus and inadequate convergence) and of functional lateral characteristics (eye preference and perceptually privileged visual laterality)? Recordings of the binocular eye-movements of ten-year-old children show that oculomotor imbalances occur most often among children whose left visual perceptual channel is privileged, and that these subjects can present optomotor dissociation and manifest lack of motor coordination. Close binocular motor coordination is far from being the norm in reading. The faster reader displays saccades of differing spatial amplitude and the slower reader an oculomotor hyperactivity, especially during fixations. The recording of binocular movements in reading appears to be an excellent means of diagnosing difficulties related to visual laterality and to problems associated with oculomotor imbalance.

Transient severe motion artifact related to gadoxetate disodium-enhanced liver MRI. Frequency and risk evaluation at a German institution

Energy Technology Data Exchange (ETDEWEB)

Well, Lennart; Rausch, Vanessa Hanna; Adam, Gerhard; Henes, Frank Oliver; Bannas, Peter [Univ. Medical Center Hamburg-Eppendorf, Hamburg (Germany). Dept. for Diagnostic and Interventional Radiology and Nuclear Medicine

2017-07-15

Varying frequencies (5 - 18%) of contrast-related transient severe motion (TSM) imaging artifacts during gadoxetate disodium-enhanced arterial phase liver MRI have been reported. Since previous reports originated from the United States and Japan, we aimed to determine the frequency of TSM at a German institution and to correlate it with potential risk factors and previously published results. Two age- and sex-matched groups were retrospectively selected (gadoxetate disodium n = 89; gadobenate dimeglumine n = 89) from dynamic contrast-enhanced MRI examinations in a single center. Respiratory motion-related artifacts in non-enhanced and dynamic phases were assessed independently by two readers blinded to contrast agents on a 4-point scale. Scores of ≥3 were considered as severe motion artifacts. Severe motion artifacts in arterial phases were considered as TSM if scores in all other phases were < 3. Potential risk factors for TSM were evaluated via logistic regression analysis. For gadoxetate disodium, the mean score for respiratory motion artifacts was significantly higher in the arterial phase (2.2 ± 0.9) compared to all other phases (1.6 ± 0.7) (p < 0.05). The frequency of TSM was significantly higher with gadoxetate disodium (n = 19; 21.1 %) than with gadobenate dimeglumine (n = 1; 1.1%) (p < 0.001). The frequency of TSM at our institution is similar to some, but not all previously published findings. Logistic regression analysis did not show any significant correlation between TSM and risk factors (all p>0.05). We revealed a high frequency of TSM after injection of gadoxetate disodium at a German institution, substantiating the importance of a diagnosis-limiting phenomenon that so far has only been reported from the United States and Japan. In accordance with previous studies, we did not identify associated risk factors for TSM.

Deriving the equations of motion of porous isotropic media

International Nuclear Information System (INIS)

Pride, S.R.; Gangi, A.F.; Morgan, F.D.

1992-01-01

The equations of motion and stress/strain relations for the linear dynamics of a two-phase, fluid/solid, isotropic, porous material have been derived by a direct volume averaging of the equations of motion and stress-strain relations known to apply in each phase. The equations thus obtained are shown to be consistent with Biot's equations of motion and stress/strain relations; however, the effective fluid density in the equation of relative flow has an unambiguous definition in terms of the tractions acting on the pore walls. The stress/strain relations of the theory correspond to 'quasistatic' stressing (i.e., inertial effects are ignored). It is demonstrated that using such quasistatic stress/strain relations in the equations of motion is justified whenever the wavelengths are greater than a length characteristic of the averaging volume size. 37 refs., 2 figs

Towards the Rational Design of MRI Contrast Agents: Electron Spin Relaxation Is Largely Unaffected by the Coordination Geometry of Gadolinium(III)–DOTA-Type Complexes

Science.gov (United States)

Bean, Jonathan F.; Clarkson, Robert B.; Helm, Lothar; Moriggi, Loïck; Sherry, A. Dean

2009-01-01

Electron-spin relaxation is one of the determining factors in the efficacy of MRI contrast agents. Of all the parameters involved in determining relaxivity it remains the least well understood, particularly as it relates to the structure of the complex. One of the reasons for the poor understanding of electron-spin relaxation is that it is closely related to the ligand-field parameters of the Gd3+ ion that forms the basis of MRI contrast agents and these complexes generally exhibit a structural isomerism that inherently complicates the study of electron spin relaxation. We have recently shown that two DOTA-type ligands could be synthesised that, when coordinated to Gd3+, would adopt well defined coordination geometries and are not subject to the problems of intramolecular motion of other complexes. The EPR properties of these two chelates were studied and the results examined with theory to probe their electron-spin relaxation properties. PMID:18283704

First steps towards ultrasound-based motion compensation for imaging and therapy: calibration with an optical system and 4D PET imaging

Directory of Open Access Journals (Sweden)

Julia eSchwaab

2015-11-01

Full Text Available Target motion, particularly in the abdomen, due to respiration or patient movement is still a challenge in many diagnostic and therapeutic processes. Hence, methods to detect and compensate this motion are required. Diagnostic ultrasound represents a non-invasive and dose-free alternative to fluoroscopy, providing more information about internal target motion than respiration belt or optical tracking.The goal of this project is to develop an ultrasound based motion tracking for real time motion correction in radiation therapy and diagnostic imaging, notably in 4D positron emission tomography (PET. In this work, a workflow is established to enable the transformation of ultrasound tracking data to the coordinates of the treatment delivery or imaging system – even if the ultrasound probe is moving due to respiration. It is shown that the ultrasound tracking signal is equally adequate for 4D PET image reconstruction as the clinically used respiration belt and provides additional opportunities in this concern. Furthermore, it is demonstrated that the ultrasound probe being within the PET field of view generally has no relevant influence on the image quality. The accuracy and precision of all the steps in the calibration workflow for ultrasound tracking based 4D PET imaging are found to be in an acceptable range for clinical implementation. Eventually, we show in vitro that an ultrasound based motion tracking in absolute room coordinates with a moving US-transducer is feasible.

Bimanual motor coordination controlled by cooperative interactions in intrinsic and extrinsic coordinates.

Science.gov (United States)

Sakurada, Takeshi; Ito, Koji; Gomi, Hiroaki

2016-01-01

Although strong motor coordination in intrinsic muscle coordinates has frequently been reported for bimanual movements, coordination in extrinsic visual coordinates is also crucial in various bimanual tasks. To explore the bimanual coordination mechanisms in terms of the frame of reference, here we characterized implicit bilateral interactions in visuomotor tasks. Visual perturbations (finger-cursor gain change) were applied while participants performed a rhythmic tracking task with both index fingers under an in-phase or anti-phase relationship in extrinsic coordinates. When they corrected the right finger's amplitude, the left finger's amplitude unintentionally also changed [motor interference (MI)], despite the instruction to keep its amplitude constant. Notably, we observed two specificities: one was large MI and low relative-phase variability (PV) under the intrinsic in-phase condition, and the other was large MI and high PV under the extrinsic in-phase condition. Additionally, using a multiple-interaction model, we successfully decomposed MI into intrinsic components caused by motor correction and extrinsic components caused by visual-cursor mismatch of the right finger's movements. This analysis revealed that the central nervous system facilitates MI by combining intrinsic and extrinsic components in the condition with in-phases in both intrinsic and extrinsic coordinates, and that under-additivity of the effects is explained by the brain's preference for the intrinsic interaction over extrinsic interaction. In contrast, the PV was significantly correlated with the intrinsic component, suggesting that the intrinsic interaction dominantly contributed to bimanual movement stabilization. The inconsistent features of MI and PV suggest that the central nervous system regulates multiple levels of bilateral interactions for various bimanual tasks. © 2015 The Authors. European Journal of Neuroscience published by Federation of European Neuroscience Societies and

Tangent Orbital Rendezvous Using Linear Relative Motion with J2 Perturbations

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Gang Zhang

2013-01-01

Full Text Available The tangent-impulse coplanar orbit rendezvous problem is studied based on the linear relative motion for J2-perturbed elliptic orbits. There are three cases: (1 only the first impulse is tangent; (2 only the second impulse is tangent; (3 both impulses are tangent. For a given initial impulse point, the first two problems can be transformed into finding all roots of a single variable function about the transfer time, which can be done by the secant method. The bitangent rendezvous problem requires the same solution for the first two problems. By considering the initial coasting time, the bitangent rendezvous solution is obtained with a difference function. A numerical example for two coplanar elliptic orbits with J2 perturbations is given to verify the efficiency of these proposed techniques.

Motion sickness: a negative reinforcement model.

Science.gov (United States)

Bowins, Brad

2010-01-15

Theories pertaining to the "why" of motion sickness are in short supply relative to those detailing the "how." Considering the profoundly disturbing and dysfunctional symptoms of motion sickness, it is difficult to conceive of why this condition is so strongly biologically based in humans and most other mammalian and primate species. It is posited that motion sickness evolved as a potent negative reinforcement system designed to terminate motion involving sensory conflict or postural instability. During our evolution and that of many other species, motion of this type would have impaired evolutionary fitness via injury and/or signaling weakness and vulnerability to predators. The symptoms of motion sickness strongly motivate the individual to terminate the offending motion by early avoidance, cessation of movement, or removal of oneself from the source. The motion sickness negative reinforcement mechanism functions much like pain to strongly motivate evolutionary fitness preserving behavior. Alternative why theories focusing on the elimination of neurotoxins and the discouragement of motion programs yielding vestibular conflict suffer from several problems, foremost that neither can account for the rarity of motion sickness in infants and toddlers. The negative reinforcement model proposed here readily accounts for the absence of motion sickness in infants and toddlers, in that providing strong motivation to terminate aberrant motion does not make sense until a child is old enough to act on this motivation.

Adiabatic time-dependent Hartree-Fock theory of collective motion in finite systems

International Nuclear Information System (INIS)

Baranger, M.; Veneroni, M.

1978-01-01

We show how to derive the parameters of a phenomenological collective model from a microscopic theory. The microscopic theory is Hartree-Fock, and we start from the time-dependent Hartree-Fock equation. To this we add the adiabatic approximation, which results in a collective kinetic energy quadratic in the velocities, with coefficients depending on the coordinates, as in the phenomenological models. The crucial step is the decomposition of the single-particle density matrix p in the form exp(i/sub chi/) rho/sub omicron/exp(-i/sub chi/), where rho/sub omicron/ represents a time-even Slater determinant and plays the role of coordinate. Then chi plays the role of momentum, and the adiabatic assumption is that chi is small. The energy is expanded in powers of chi, the zeroth-order being the collective potential energy. The analogy with classical mechanics is stressed and studied. The same adiabatic equations of motion are derived in three different ways (directly, from the Lagrangian, from the Hamiltonian), thus proving the consistency of the theory. The dynamical equation is not necessary for writing the energy or for the subsequent quantization which leads to a Schroedinger equation, but it must be used to check the validity of various approximation schemes, particularly to reduce the problem to a few degrees of freedom. The role of the adiabatic hypothesis, its definition, and range of validity, are analyzed in great detail. It assumes slow motion, but not small amplitude, and is therefore suitable for large-amplitude collective motion. The RPA is obtained as the limiting case where the amplitude is also small. The translational mass is correctly given, and the moment of inertia under rotation is that of Thouless and Valatin. For a quadrupole two-body force, the Baranger-Kumar formalism is recovered. The self-consistency brings additional terms to the Inglis cranking formula. Comparison is also made with generator coordinate methods

Quantitative assessment of paretic limb dexterity and interlimb coordination during bilateral arm rehabilitation training.

Science.gov (United States)

Xu, Chang; Li, Siyi; Wang, Kui; Hou, Zengguang; Yu, Ningbo

2017-07-01

In neuro-rehabilitation after stroke, the conventional constrained induced movement therapy (CIMT) has been well-accepted. Existing bilateral trainings are mostly on mirrored symmetrical motion. However, complementary bilateral movements are dominantly involved in activities of daily living (ADLs), and functional bilateral therapies may bring better skill transfer from trainings to daily life. Neurophysiological evidence is also growing. In this work, we firstly introduce our bilateral arm training system realized with a haptic interface and a motion sensor, as well as the tasks that have been designed to train both the manipulation function of the paretic arm and coordination of bilateral upper limbs. Then, we propose quantitative measures for functional assessment of complementary bilateral training performance, including kinematic behavior indices, smoothness, submovement and bimanual coordination. After that, we describe the experiments with healthy subjects and the results with respect to these quantitative measures. Feasibility and sensitivity of the proposed indices were evaluated through comparison of unilateral and bilateral training outcomes. The proposed bilateral training system and tasks, as well as the quantitative measures, have been demonstrated effective for training and assessment of unilateral and bilateral arm functions.

Clinical significance of perceptible fetal motion.

Science.gov (United States)

Rayburn, W F

1980-09-15

The monitoring of fetal activity during the last trimester of pregnancy has been proposed to be useful in assessing fetal welfare. The maternal perception of fetal activity was tested among 82 patients using real-time ultrasonography. All perceived fetal movements were visualized on the scanner and involved motion of the lower limbs. Conversely, 82% of all visualized motions of fetal limbs were perceived by the patients. All combined motions of fetal trunk with limbs were preceived by the patients and described as strong movements, whereas clusters of isolated, weak motions of the fetal limbs were less accurately perceived (56% accuracy). The number of fetal movements perceived during the 15-minute test period was significantly (p fetal motion was present (44 of 45 cases) than when it was absent (five of 10 cases). These findings reveal that perceived fetal motion is: (1) reliable; (2) related to the strength of lower limb motion; (3) increased with ruptured amniotic membranes; and (4) reassuring if considered to be active.

Generator coordinate method for triaxial quadrupole collective dynamics in strontium isotopes

International Nuclear Information System (INIS)

Bonche, P.; Dobaczewski, J.; Flocard, H.; Heenen, P.H.

1991-01-01

We discuss the algebraic structure of the generator coordinate method for triaxial quadrupole collective motion. The collective solutions are classified according to the representations of the permutation group of the intrinsic axes. Our method amounts to an approximate angular momentum projection. We apply it to a study of the spherical to deformed shape transition in light even strontium isotopes 78-88 Sr. We find that triaxial configurations play a significant role in explaining the structure of the transitional isotopes 80-82 Sr

Coordinate transformations, orthographic projections, and robot kinematics

International Nuclear Information System (INIS)

Crochetiere, W.J.

1984-01-01

Humans do not consciously think of moving each of their joints while they move their hands from one place to another. Likewise, robot arms can be commanded to move about in cartesian space without the need to address the individual joints. To do this, the direct and inverse kinematic equations of any robot arm must be derived. The direct kinematic equations uniquely transform the joint positions into the position (and orientation) of the hand, whereas the inverse kinematic equations transform the position (and orientation) of the hand into joint positions. The derivation of the inverse kinematic equations for any particular robot is a difficult problem which may have more than one solution. In this paper, these equations are derived for a six degree of freedom robot arm. A combination of matrix operations to perform coordinate rotations, and trigonometry within the appropriate orthographic projects to perform coordinate translations is employed. This complementary approach yields a solution which is more easily obtained, and also more easily visualized. The resulting solution was programmed into a real-time computer as a part of a higher level software system to control the motion of the arm

Micro-motion Recognition of Spatial Cone Target Based on ISAR Image Sequences

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Changyong Shu

2016-04-01

Full Text Available The accurate micro-motions recognition of spatial cone target is the foundation of the characteristic parameter acquisition. For this reason, a micro-motion recognition method based on the distinguishing characteristics extracted from the Inverse Synthetic Aperture Radar (ISAR sequences is proposed in this paper. The projection trajectory formula of cone node strong scattering source and cone bottom slip-type strong scattering sources, which are located on the spatial cone target, are deduced under three micro-motion types including nutation, precession, and spinning, and the correctness is verified by the electromagnetic simulation. By comparison, differences are found among the projection of the scattering sources with different micro-motions, the coordinate information of the scattering sources in the Inverse Synthetic Aperture Radar sequences is extracted by the CLEAN algorithm, and the spinning is recognized by setting the threshold value of Doppler. The double observation points Interacting Multiple Model Kalman Filter is used to separate the scattering sources projection of the nutation target or precession target, and the cross point number of each scattering source’s projection track is used to classify the nutation or precession. Finally, the electromagnetic simulation data are used to verify the effectiveness of the micro-motion recognition method.

Extraction and Analysis of Respiratory Motion Using Wearable Inertial Sensor System during Trunk Motion

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Apoorva Gaidhani

2017-12-01

Full Text Available Respiratory activity is an essential vital sign of life that can indicate changes in typical breathing patterns and irregular body functions such as asthma and panic attacks. Many times, there is a need to monitor breathing activity while performing day-to-day functions such as standing, bending, trunk stretching or during yoga exercises. A single IMU (inertial measurement unit can be used in measuring respiratory motion; however, breathing motion data may be influenced by a body trunk movement that occurs while recording respiratory activity. This research employs a pair of wireless, wearable IMU sensors custom-made by the Department of Electrical Engineering at San Diego State University. After appropriate sensor placement for data collection, this research applies principles of robotics, using the Denavit-Hartenberg convention, to extract relative angular motion between the two sensors. One of the obtained relative joint angles in the “Sagittal” plane predominantly yields respiratory activity. An improvised version of the proposed method and wearable, wireless sensors can be suitable to extract respiratory information while performing sports or exercises, as they do not restrict body motion or the choice of location to gather data.

Modeling, Control and Coordination of Helicopter Systems

CERN Document Server

Ren, Beibei; Chen, Chang; Fua, Cheng-Heng; Lee, Tong Heng

2012-01-01

Modeling, Control and Coordination of Helicopter Systems provides a comprehensive treatment of helicopter systems, ranging from related nonlinear flight dynamic modeling and stability analysis to advanced control design for single helicopter systems, and also covers issues related to the coordination and formation control of multiple helicopter systems to achieve high performance tasks. Ensuring stability in helicopter flight is a challenging problem for nonlinear control design and development. This book is a valuable reference on modeling, control and coordination of helicopter systems,providing readers with practical solutions for the problems that still plague helicopter system design and implementation. Readers will gain a complete picture of helicopters at the systems level, as well as a better understanding of the technical intricacies involved. This book also: Presents a complete picture of modeling, control and coordination for helicopter systems Provides a modeling platform for a general class of ro...