Reliability of psychophysiological responses across multiple motion sickness stimulation tests

Science.gov (United States)

Stout, C. S.; Toscano, W. B.; Cowings, P. S.

1995-01-01

Although there is general agreement that a high degree of variability exists between subjects in their autonomic nervous system responses to motion sickness stimulation, very little evidence exists that examines the reproducibility of autonomic responses within subjects during motion sickness stimulation. Our objectives were to examine the reliability of autonomic responses and symptom levels across five testing occasions using the (1) final minute of testing, (2) change in autonomic response and the change in symptom level, and (3) strength of the relationship between the change in symptom level and the change in autonomic responses across the entire motion sickness test. The results indicate that, based on the final minute of testing, the autonomic responses of heart rate, blood volume pulse, and respiration rate are moderately stable across multiple tests. Changes in heart rate, blood volume pulse, respiration rate, and symptoms throughout the test duration are less stable across the tests. Finally, autonomic responses and symptom levels are significantly related across the entire motion sickness test.

Features of librational motions around L4

International Nuclear Information System (INIS)

Rajnai, Renata; Erdi, Balint; Nagy, Imre

2010-01-01

Trojan bodies are present in the Solar system in great number, as Trojan asteroids and also as Trojan moons. Thus it is possible that their presence is similar in extrasolar planetary systems too. We investigated features of librational motions around L 4 with numerical methods on the mass parameter - eccentricity plane in the elliptic restricted three-body problem. We determined the lifetime of Trojan bodies, until they remained in the librational domain around L 4 , also illustrated the distribution of the three possible endgames of trojan motion. Finally we determined the frequences and resonances of the librational motion in the stable region.

Shallow and deep controls on lava lake surface motion at Kīlauea Volcano

Science.gov (United States)

Patrick, Matthew R.; Orr, Tim R.; Swanson, Don; Lev, Einat

2016-01-01

Lava lakes provide a rare window into magmatic behavior, and lake surface motion has been used to infer deeper properties of the magmatic system. At Halema'uma'u Crater, at the summit of Kīlauea Volcano, multidisciplinary observations for the past several years indicate that lava lake surface motion can be broadly divided into two regimes: 1) stable and 2) unstable. Stable behavior is driven by lava upwelling from deeper in the lake (presumably directly from the conduit) and is an intrinsic process that drives lava lake surface motion most of the time. This stable behavior can be interrupted by periods of unstable flow (often reversals) driven by spattering – a shallowly-rooted process often extrinsically triggered by small rockfalls from the crater wall. The bursting bubbles at spatter sources create void spaces and a localized surface depression which draws and consumes surrounding surface crust. Spattering is therefore a location of lava downwelling, not upwelling. Stable (i.e. deep, upwelling-driven) and unstable (i.e. shallow, spattering-driven) behavior often alternate through time, have characteristic surface velocities, flow directions and surface temperature regimes, and also correspond to changes in spattering intensity, outgassing rates, lava level and seismic tremor. These results highlight that several processes, originating at different depths, can control the motion of the lava lake surface, and long-term interdisciplinary monitoring is required to separate these influences. These observations indicate that lake surface motion is not always a reliable proxy for deeper lake or magmatic processes. From these observations, we suggest that shallow outgassing (spattering), not lake convection, drives the variations in lake motion reported at Erta 'Ale lava lake.

Motion of rectangular prismatic bodies

International Nuclear Information System (INIS)

Poreh, M.; Wray, R.N.

1979-01-01

Rectangular prismatic bodies can assume either a translatory or an auto-rotating mode of motion during free motion in the atmosphere. The translatory mode is stable only when the dimensionless moment of inertia of the bodies is large, however, large perturbations will always start auto-rotation. The characteristics of the auto-rotational mode are shown to depend primarily on the aspect ratio of the bodies which determines the dimensionless rotational speed and the lift coefficient. Both the average drag and lift-coefficients of auto-rotating bodies are estimated, but it is shown that secondary effects make it impossible to determine their exact trajectories in atmospheric flows

Features of librational motions around L{sub 4}

Energy Technology Data Exchange (ETDEWEB)

Rajnai, Renata; Erdi, Balint [Department of Astronomy, Eoetvoes University, Pazmany Peter setany 1/A, 1117 Budapest (Hungary); Nagy, Imre, E-mail: R.Rajnai@astro.elte.h [Physical Geodesy and Geodesical Research Group of the HAS, Technical University, Muegyetem rkp. 3, 1111 Budapest (Hungary)

2010-03-01

Trojan bodies are present in the Solar system in great number, as Trojan asteroids and also as Trojan moons. Thus it is possible that their presence is similar in extrasolar planetary systems too. We investigated features of librational motions around L{sub 4} with numerical methods on the mass parameter - eccentricity plane in the elliptic restricted three-body problem. We determined the lifetime of Trojan bodies, until they remained in the librational domain around L{sub 4}, also illustrated the distribution of the three possible endgames of trojan motion. Finally we determined the frequences and resonances of the librational motion in the stable region.

Articulated Human Motion Tracking Using Sequential Immune Genetic Algorithm

Directory of Open Access Journals (Sweden)

Yi Li

2013-01-01

Full Text Available We formulate human motion tracking as a high-dimensional constrained optimization problem. A novel generative method is proposed for human motion tracking in the framework of evolutionary computation. The main contribution is that we introduce immune genetic algorithm (IGA for pose optimization in latent space of human motion. Firstly, we perform human motion analysis in the learnt latent space of human motion. As the latent space is low dimensional and contents the prior knowledge of human motion, it makes pose analysis more efficient and accurate. Then, in the search strategy, we apply IGA for pose optimization. Compared with genetic algorithm and other evolutionary methods, its main advantage is the ability to use the prior knowledge of human motion. We design an IGA-based method to estimate human pose from static images for initialization of motion tracking. And we propose a sequential IGA (S-IGA algorithm for motion tracking by incorporating the temporal continuity information into the traditional IGA. Experimental results on different videos of different motion types show that our IGA-based pose estimation method can be used for initialization of motion tracking. The S-IGA-based motion tracking method can achieve accurate and stable tracking of 3D human motion.

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

Directory of Open Access Journals (Sweden)

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.

The tempered stable process with infinitely divisible inverse subordinators

International Nuclear Information System (INIS)

Wyłomańska, Agnieszka

2013-01-01

In the last decade processes driven by inverse subordinators have become extremely popular. They have been used in many different applications, especially for data with observable constant time periods. However, the classical model, i.e. the subordinated Brownian motion, can be inappropriate for the description of observed phenomena that exhibit behavior not adequate for Gaussian systems. Therefore, in this paper we extend the classical approach and replace the Brownian motion by the tempered stable process. Moreover, on the other hand, as an extension of the classical model, we analyze the general class of inverse subordinators. We examine the main properties of the tempered stable process driven by inverse subordinators from the infinitely divisible class of distributions. We show the fractional Fokker–Planck equation of the examined process and the asymptotic behavior of the mean square displacement for two cases of subordinators. Additionally, we examine how an external force can influence the examined characteristics. (paper)

Motion of the moonlet in the binary system 243 Ida

Science.gov (United States)

Lan, L.; Ni, Y.; Jiang, Y.; Li, J.

2018-02-01

The motion of the moonlet Dactyl in the binary system 243 Ida is investigated in this paper. First, periodic orbits in the vicinity of the primary are calculated, including the orbits around the equilibrium points and large-scale orbits. The Floquet multipliers' topological cases of periodic orbits are calculated to study the orbits' stabilities. During the continuation of the retrograde near-circular orbits near the equatorial plane, two period-doubling bifurcations and one Neimark-Sacker bifurcation occur one by one, leading to two stable regions and two unstable regions. Bifurcations occur at the boundaries of these regions. Periodic orbits in the stable regions are all stable, but in the unstable regions are all unstable. Moreover, many quasi-periodic orbits exist near the equatorial plane. Long-term integration indicates that a particle in a quasi-periodic orbit runs in a space like a tire. Quasi-periodic orbits in different regions have different styles of motion indicated by the Poincare sections. There is the possibility that moonlet Dactyl is in a quasi-periodic orbit near the stable region I, which is enlightening for the stability of the binary system.

Motion characteristic of a free piston linear engine

Energy Technology Data Exchange (ETDEWEB)

Xiao, Jin; Li, Qingfeng; Huang, Zhen [Key Laboratory for Power Machinery and Engineering of Ministry of Education, Shanghai Jiao Tong University, Shanghai, 200240 (China)

2010-04-15

A mathematical model of a free piston linear engine is established. The motion characteristics as well as the natural frequency map of the free piston are established. Then, its motion characteristics are successfully explained from the oscillation point. The full simulation model is built up in Matlab/Simulink for a better understanding of its motion features. The results show that the free piston system is a forced vibration system with variable damping coefficient and stiffness. Its steady-state response of periodical excitation is convergent which means that the system is stable under the periodical combustion. Furthermore, it has some unique features which are different from those of traditional Internal Combustion (IC) engines. (author)

Changing predictions, stable recognition: Children’s representations of downward incline motion

OpenAIRE

Hast, Michael; Howe, Christine

2017-01-01

Various studies to-date have demonstrated children hold ill-conceived expressed beliefs about the physical world such as that one ball will fall faster than another because it is heavier. At the same time they also demonstrate accurate recognition of dynamic events. How these representations relate is still unresolved. This study examined 5- to 11-year-olds’ (N = 130) predictions and recognition of motion down inclines. Predictions were typically in error, matching previous work, but children...

Reliability of Autonomic Responses and Malaise Across Multiple Motion Sickness Stimulation Tests

Science.gov (United States)

Stout, Cynthia S.; Toscano, William B.; Cowings, Patricia S.

1993-01-01

There is general agreement that a high degree of variability exists between subjects in their autonomic nervous system responses to motion sickness stimulation. Additionally, a paucity of data exists that examines the variability within an individual across repeated motion sickness tests. Investigators have also examined the relationship of autonomic responses to motion sickness development. These investigations have used analyses at discrete points in time to describe this relationship. This approach fails to address the time course of autonomic responses and malaise development throughout the motion sickness test. Our objectives were to examine the reliability of autonomic responses and malaise using the final minute of the motion sickness test across five testing occasions, to examine the reliability of the change in autonomic responses and the change in malaise across five testing occasions, and to examine the relationship between changes in autonomic responses and changes in malaise level across the entire motion sickness test. Our results indicate that, based on the final minute of testing, the autonomic responses of heart rate, blood volume pulse, and respiration rate are moderately stable across multiple tests. Changes in heart rate, blood volume pulse, respiration rate, and malaise throughout the test duration were less stable across the tests. We attribute this instability to variations in individual susceptibility and the error associated with estimating a measure of autonomic gain.

Synthesis of High-Frequency Ground Motion Using Information Extracted from Low-Frequency Ground Motion

Science.gov (United States)

Iwaki, A.; Fujiwara, H.

2012-12-01

Broadband ground motion computations of scenario earthquakes are often based on hybrid methods that are the combinations of deterministic approach in lower frequency band and stochastic approach in higher frequency band. Typical computation methods for low-frequency and high-frequency (LF and HF, respectively) ground motions are the numerical simulations, such as finite-difference and finite-element methods based on three-dimensional velocity structure model, and the stochastic Green's function method, respectively. In such hybrid methods, LF and HF wave fields are generated through two different methods that are completely independent of each other, and are combined at the matching frequency. However, LF and HF wave fields are essentially not independent as long as they are from the same event. In this study, we focus on the relation among acceleration envelopes at different frequency bands, and attempt to synthesize HF ground motion using the information extracted from LF ground motion, aiming to propose a new method for broad-band strong motion prediction. Our study area is Kanto area, Japan. We use the K-NET and KiK-net surface acceleration data and compute RMS envelope at four frequency bands: 0.5-1.0 Hz, 1.0-2.0 Hz, 2.0-4.0 Hz, .0-8.0 Hz, and 8.0-16.0 Hz. Taking the ratio of the envelopes of adjacent bands, we find that the envelope ratios have stable shapes at each site. The empirical envelope-ratio characteristics are combined with low-frequency envelope of the target earthquake to synthesize HF ground motion. We have applied the method to M5-class earthquakes and a M7 target earthquake that occurred in the vicinity of Kanto area, and successfully reproduced the observed HF ground motion of the target earthquake. The method can be applied to a broad band ground motion simulation for a scenario earthquake by combining numerically-computed low-frequency (~1 Hz) ground motion with the empirical envelope ratio characteristics to generate broadband ground motion

Modelling of the flow of stable air over a complex region

CSIR Research Space (South Africa)

Scholtz, MT

1976-01-01

Full Text Available The flow of stable air over a general region of complex topography and non-uniform surface temperature has been investigated. In order to gain further understanding of the motion of surface air, it was necessary to study the vertical structure...

State Generation Method for Humanoid Motion Planning Based on Genetic Algorithm

Directory of Open Access Journals (Sweden)

Xuyang Wang

2012-05-01

Full Text Available A new approach to generate the original motion data for humanoid motion planning is presented in this paper. And a state generator is developed based on the genetic algorithm, which enables users to generate various motion states without using any reference motion data. By specifying various types of constraints such as configuration constraints and contact constraints, the state generator can generate stable states that satisfy the constraint conditions for humanoid robots. To deal with the multiple constraints and inverse kinematics, the state generation is finally simplified as a problem of optimizing and searching. In our method, we introduce a convenient mathematic representation for the constraints involved in the state generator, and solve the optimization problem with the genetic algorithm to acquire a desired state. To demonstrate the effectiveness and advantage of the method, a number of motion states are generated according to the requirements of the motion.

State Generation Method for Humanoid Motion Planning Based on Genetic Algorithm

Directory of Open Access Journals (Sweden)

Xuyang Wang

2008-11-01

Full Text Available A new approach to generate the original motion data for humanoid motion planning is presented in this paper. And a state generator is developed based on the genetic algorithm, which enables users to generate various motion states without using any reference motion data. By specifying various types of constraints such as configuration constraints and contact constraints, the state generator can generate stable states that satisfy the constraint conditions for humanoid robots.To deal with the multiple constraints and inverse kinematics, the state generation is finally simplified as a problem of optimizing and searching. In our method, we introduce a convenient mathematic representation for the constraints involved in the state generator, and solve the optimization problem with the genetic algorithm to acquire a desired state. To demonstrate the effectiveness and advantage of the method, a number of motion states are generated according to the requirements of the motion.

Measurement of spin motions in a storage ring outside the stable polarization direction

International Nuclear Information System (INIS)

Akchurin, N.; Badano, L.; Bravar, A.; Istituto Nazionale di Fisica Nucleare, Legnaro

1993-06-01

Polarized, stored beams are becoming a more and more important tool in nuclear and high energy physics. In order to measure the beam polarization in a storage ring the polarization vector of the stored beams has to aim, revolution for revolution, over a period of seconds to minutes, into the same, so-called ''stable'' direction. In this paper measurements at the Indiana University cooler ring (IUCF) are described in which for the first time in a storage ring oscillations of the polarization vector around this stable direction have been measured. The existence and the dynamics of such oscillations are, for instance, important for a new proposed technique for polarizing stored hadron beams

The application of mean field theory to image motion estimation.

Science.gov (United States)

Zhang, J; Hanauer, G G

1995-01-01

Previously, Markov random field (MRF) model-based techniques have been proposed for image motion estimation. Since motion estimation is usually an ill-posed problem, various constraints are needed to obtain a unique and stable solution. The main advantage of the MRF approach is its capacity to incorporate such constraints, for instance, motion continuity within an object and motion discontinuity at the boundaries between objects. In the MRF approach, motion estimation is often formulated as an optimization problem, and two frequently used optimization methods are simulated annealing (SA) and iterative-conditional mode (ICM). Although the SA is theoretically optimal in the sense of finding the global optimum, it usually takes many iterations to converge. The ICM, on the other hand, converges quickly, but its results are often unsatisfactory due to its "hard decision" nature. Previously, the authors have applied the mean field theory to image segmentation and image restoration problems. It provides results nearly as good as SA but with much faster convergence. The present paper shows how the mean field theory can be applied to MRF model-based motion estimation. This approach is demonstrated on both synthetic and real-world images, where it produced good motion estimates.

Motion of charged test particles in Reissner-Nordstroem spacetime

International Nuclear Information System (INIS)

Pugliese, Daniela; Quevedo, Hernando; Ruffini, Remo

2011-01-01

We investigate the circular motion of charged test particles in the gravitational field of a charged mass described by the Reissner-Nordstroem spacetime. We study in detail all the spatial regions where circular motion is allowed around either black holes or naked singularities. The effects of repulsive gravity are discussed by finding all the circles at which a particle can have vanishing angular momentum. We show that the geometric structure of stable accretion disks, made of only test particles moving along circular orbits around the central body, allows us to clearly distinguish between black holes and naked singularities.

Integration of visual and non-visual self-motion cues during voluntary head movements in the human brain.

Science.gov (United States)

Schindler, Andreas; Bartels, Andreas

2018-05-15

Our phenomenological experience of the stable world is maintained by continuous integration of visual self-motion with extra-retinal signals. However, due to conventional constraints of fMRI acquisition in humans, neural responses to visuo-vestibular integration have only been studied using artificial stimuli, in the absence of voluntary head-motion. We here circumvented these limitations and let participants to move their heads during scanning. The slow dynamics of the BOLD signal allowed us to acquire neural signal related to head motion after the observer's head was stabilized by inflatable aircushions. Visual stimuli were presented on head-fixed display goggles and updated in real time as a function of head-motion that was tracked using an external camera. Two conditions simulated forward translation of the participant. During physical head rotation, the congruent condition simulated a stable world, whereas the incongruent condition added arbitrary lateral motion. Importantly, both conditions were precisely matched in visual properties and head-rotation. By comparing congruent with incongruent conditions we found evidence consistent with the multi-modal integration of visual cues with head motion into a coherent "stable world" percept in the parietal operculum and in an anterior part of parieto-insular cortex (aPIC). In the visual motion network, human regions MST, a dorsal part of VIP, the cingulate sulcus visual area (CSv) and a region in precuneus (Pc) showed differential responses to the same contrast. The results demonstrate for the first time neural multimodal interactions between precisely matched congruent versus incongruent visual and non-visual cues during physical head-movement in the human brain. The methodological approach opens the path to a new class of fMRI studies with unprecedented temporal and spatial control over visuo-vestibular stimulation. Copyright © 2018 Elsevier Inc. All rights reserved.

Motions in the relativistic fields of a charged dust

International Nuclear Information System (INIS)

Fonseca Teixeira, A.F. da.

1980-04-01

The general relativistic motion of arbitrarily charged test particles is investigated, in the spherically symmetric fields of a charged, static, incoherent matter with T 0 0 = const. The condition for existence of stable circular orbits is established, inside and outside the diffused source. The null geodesics are also investigated, as a limiting case. (Author) [pt

A model of ATL ground motion for storage rings

International Nuclear Information System (INIS)

Wolski, Andrzej; Walker, Nicholas J.

2003-01-01

Low emittance electron storage rings, such as those used in third generation light sources or linear collider damping rings, rely for their performance on highly stable alignment of the lattice components. Even if all vibration and environmental noise sources could be suppressed, diffusive ground motion will lead to orbit drift and emittance growth. Understanding such motion is important for predicting the performance of a planned accelerator and designing a correction system. A description (known as the ATL model) of ground motion over relatively long time scales has been developed and has become the standard for studies of the long straight beamlines in linear colliders. Here, we show how the model may be developed to include beamlines of any geometry. We apply the model to the NLC and TESLA damping rings, to compare their relative stability under different conditions

Sausage instabilities stabilized by radial motion in Z-discharged plasma channel for beam propagation in LIB-fusion

International Nuclear Information System (INIS)

Murakami, Hiroyuki; Kawata, Shigeo; Niu, Keishiro.

1983-01-01

The stability of current-carrying plasma channels, which have been proposed for transporting intense ion beams from the diodes to the target in LIB-fusion devices, is discussed. The growth rate of the most dangerous surface mode, that is, the axisymmetric sausage instabilities, are examined for plasma channels with or without radial fluid motion. The growth rate of the channel with radial fluid motion is shown to be far smaller than that of the channel with no fluid motion. It is concluded that a stable plasma channel can be formed by radial fluid motion. (author)

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.

Evolution of the bi-stable wake of a square-back automotive shape

Science.gov (United States)

Pavia, Giancarlo; Passmore, Martin; Sardu, Costantino

2018-01-01

Square-back shapes are popular in the automotive market for their high level of practicality. These geometries, however, are usually characterised by high drag and their wake dynamics present aspects, such as the coexistence of a long-time bi-stable behaviour and short-time global fluctuating modes that are not fully understood. In the present paper, the unsteady behaviour of the wake of a generic square-back car geometry is characterised with an emphasis on identifying the causal relationship between the different dynamic modes in the wake. The study is experimental, consisting of balance, pressure, and stereoscopic PIV measurements. Applying wavelet and cross-wavelet transforms to the balance data, a quasi-steady correlation is demonstrated between the forces and bi-stable modes. This is investigated by applying proper orthogonal decomposition to the pressure and velocity data sets and a new structure is proposed for each bi-stable state, consisting of a hairpin vortex that originates from one of the two model's vertical trailing edges and bends towards the opposite side as it merges into a single streamwise vortex downstream. The wake pumping motion is also identified and for the first time linked with the motion of the bi-stable vortical structure in the streamwise direction, resulting in out-of-phase pressure variations between the two vertical halves of the model base. A phase-averaged low-order model is also proposed that provides a comprehensive description of the mechanisms of the switch between the bi-stable states. It is demonstrated that, during the switch, the wake becomes laterally symmetric and, at this point, the level of interaction between the recirculating structures and the base reaches a minimum, yielding, for this geometry, a 7% reduction of the base drag compared to the time-averaged result.

A new look at Op art: towards a simple explanation of illusory motion

Science.gov (United States)

Zanker, Johannes M.; Walker, Robin

Vivid motion illusions created by some Op art paintings are at the centre of a lively scientific debate about possible mechanisms that might underlie these phenomena. Here we review emerging evidence from a new approach that combines perceptual judgements of the illusion and observations of eye movements with simulations of the induced optic flow. This work suggests that the small involuntary saccades which participants make when viewing such Op art patterns would generate an incoherent distribution of motion signals that resemble the perceptual effects experienced by the observers. The combined experimental and computational evidence supports the view that the illusion is indeed caused by involuntary image displacements picked up by low-level motion detectors, and further suggests that coherent motion signals are crucial to perceive a stable world.

Forward flight of swallowtail butterfly with simple flapping motion

Energy Technology Data Exchange (ETDEWEB)

Tanaka, Hiroto [School of Engineering and Applied Sciences, Harvard University, 60 Oxford Street, Cambridge, MA 02138 (United States); Shimoyama, Isao, E-mail: isao@i.u-tokyo.ac.j [Department of Mechano-Informatics, Graduate School of Information Science and Technology, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8656 (Japan)

2010-06-15

Unlike other flying insects, the wing motion of swallowtail butterflies is basically limited to flapping because their fore wings partly overlap their hind wings, structurally restricting the feathering needed for active control of aerodynamic force. Hence, it can be hypothesized that the flight of swallowtail butterflies is realized with simple flapping, requiring little feedback control of the feathering angle. To verify this hypothesis, we fabricated an artificial butterfly mimicking the wing motion and wing shape of a swallowtail butterfly and analyzed its flights using images taken with a high-speed video camera. The results demonstrated that stable forward flight could be realized without active feathering or feedback control of the wing motion. During the flights, the artificial butterfly's body moved up and down passively in synchronization with the flapping, and the artificial butterfly followed an undulating flight trajectory like an actual swallowtail butterfly. Without feedback control of the wing motion, the body movement is directly affected by change of aerodynamic force due to the wing deformation; the degree of deformation was determined by the wing venation. Unlike a veinless wing, a mimic wing with veins generated a much higher lift coefficient during the flapping flight than in a steady flow due to the large body motion.

Forward flight of swallowtail butterfly with simple flapping motion

International Nuclear Information System (INIS)

Tanaka, Hiroto; Shimoyama, Isao

2010-01-01

Unlike other flying insects, the wing motion of swallowtail butterflies is basically limited to flapping because their fore wings partly overlap their hind wings, structurally restricting the feathering needed for active control of aerodynamic force. Hence, it can be hypothesized that the flight of swallowtail butterflies is realized with simple flapping, requiring little feedback control of the feathering angle. To verify this hypothesis, we fabricated an artificial butterfly mimicking the wing motion and wing shape of a swallowtail butterfly and analyzed its flights using images taken with a high-speed video camera. The results demonstrated that stable forward flight could be realized without active feathering or feedback control of the wing motion. During the flights, the artificial butterfly's body moved up and down passively in synchronization with the flapping, and the artificial butterfly followed an undulating flight trajectory like an actual swallowtail butterfly. Without feedback control of the wing motion, the body movement is directly affected by change of aerodynamic force due to the wing deformation; the degree of deformation was determined by the wing venation. Unlike a veinless wing, a mimic wing with veins generated a much higher lift coefficient during the flapping flight than in a steady flow due to the large body motion.

MRI-based tumor motion characterization and gating schemes for radiation therapy of pancreatic cancer

International Nuclear Information System (INIS)

Heerkens, Hanne D.; Vulpen, Marco van; Berg, Cornelis A.T. van den; Tijssen, Rob H.N.; Crijns, Sjoerd P.M.; Molenaar, Izaak Q.; Santvoort, Hjalmar C. van; Reerink, Onne; Meijer, Gert J.

2014-01-01

Background and purpose: To characterize pancreatic tumor motion and to develop a gating scheme for radiotherapy in pancreatic cancer. Materials and methods: Two cine MRIs of 60 s each were performed in fifteen pancreatic cancer patients, one in sagittal direction and one in coronal direction. A Minimum Output Sum of Squared Error (MOSSE) adaptive correlation filter was used to quantify tumor motion in craniocaudal, lateral and anteroposterior directions. To develop a gating scheme, stability of the breathing phases was examined and a gating window assessment was created, incorporating tumor motion, treatment time and motion margins. Results: The largest tumor motion was found in craniocaudal direction, with an average peak-to-peak amplitude of 15 mm (range 6–34 mm). Amplitude of the tumor in the anteroposterior direction was on average 5 mm (range 1–13 mm). The least motion was seen in lateral direction (average 3 mm, range 2–5 mm). The end exhale position was the most stable position in the breathing cycle and tumors spent more time closer to the end exhale position than to the end inhale position. On average, a margin of 25% of the maximum craniocaudal breathing amplitude was needed to achieve full target coverage with a duty cycle of 50%. When reducing the duty cycle to 50%, a margin of 5 mm was sufficient to cover the target in 11 out of 15 patients. Conclusion: Gated delivery for radiotherapy of pancreatic cancer is best performed around the end exhale position as this is the most stable position in the breathing cycle. Considerable margin reduction can be established at moderate duty cycles, yielding acceptable treatment efficiency. However, motion patterns and amplitude do substantially differ between individual patients. Therefore, individual treatment strategies should be considered for radiotherapy in pancreatic cancer

Complex motion in nonlinear-map model of elevators in energy-saving traffic

Science.gov (United States)

Nagatani, Takashi

2011-05-01

We have studied the dynamic behavior and dynamic transitions of elevators in a system for reducing energy consumption. We present a nonlinear-map model for the dynamics of M elevators. The motion of elevators depends on the loading parameter and their number M. The dependence of the fixed points on the loading parameter is derived. The dynamic transitions occur at 2(M-1) stages with increasing the value of loading parameter. At the dynamic transition point, the motion of elevators changes from a stable state to an unstable state and vice versa. The elevators display periodic motions with various periods in the unstable state. In the unstable state, the number of riding passengers fluctuates in a complex manner over various trips.

Testbed for High-Acuity Imaging and Stable Photometry

Science.gov (United States)

Gregory, James

This proposal from MIT Lincoln Laboratory (LL) accompanies the NASA/APRA proposal enti-tled THAI-SPICE: Testbed for High-Acuity Imaging - Stable Photometry and Image-Motion Compensa-tion Experiment (submitted by Eliot Young, Southwest Research Institute). The goal of the THAI-SPICE project is to demonstrate three technologies that will help low-cost balloon-borne telescopes achieve diffraction-limited imaging: stable pointing, passive thermal stabilization and in-flight monitoring of the wave front error. This MIT LL proposal supplies a key element of the pointing stabilization component of THAI-SPICE: an electronic camera based on an orthogonaltransfer charge-coupled device (OTCCD). OTCCD cameras have been demonstrated with charge-transfer efficiencies >0.99999, noise of 90%. In addition to supplying a camera with an OTCCD detector, MIT LL will help with integration and testing of the OTCCD with the THAI-SPICE payload’s guide camera.

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.

The 2011 Mineral, VA M5.8 Earthquake Ground Motions and Stress Drop: An Important Contribution to the NGA East Ground Motion Database

Science.gov (United States)

Cramer, C. H.; Kutliroff, J.; Dangkua, D.

2011-12-01

The M5.8 Mineral, Virginia earthquake of August 23, 2011 is the largest instrumentally recorded earthquake in eastern North America since the 1988 M5.9 Saguenay, Canada earthquake. Historically, a similar magnitude earthquake occurred on May 31, 1897 at 18:58 UCT in western Virginia west of Roanoke. Paleoseismic evidence for larger magnitude earthquakes has also been found in the central Virginia region. The Next Generation Attenuation (NGA) East project to develop new ground motion prediction equations for stable continental regions (SCRs), including eastern North America (ENA), is ongoing at the Pacific Earthquake Engineering Research Center funded by the U.S. Nuclear Regulatory Commission, the U.S. Geological Survey, the Electric Power Research Institute, and the U.S. Department of Energy. The available recordings from the M5.8 Virginia are being added to the NGA East ground motion database. Close in (less than 100 km) strong motion recordings are particularly interesting for both ground motion and stress drop estimates as most close-in broadband seismometers clipped on the mainshock. A preliminary estimate for earthquake corner frequency for the M5.8 Virginia earthquake of ~0.7 Hz has been obtained from a strong motion record 57 km from the mainshock epicenter. For a M5.8 earthquake this suggests a Brune stress drop of ~300 bars for the Virginia event. Very preliminary comparisons using accelerometer data suggest the ground motions from the M5.8 Virginia earthquake agree well with current ENA ground motion prediction equations (GMPEs) at short periods (PGA, 0.2 s) and are below the GMPEs at longer periods (1.0 s), which is the same relationship seen from other recent M5 ENA earthquakes. We will present observed versus GMPE ground motion comparisons for all the ground motion observations and stress drop estimates from strong motion recordings at distances less than 100 km. A review of the completed NGA East ENA ground motion database will also be provided.

Psychophysical scaling of circular vection (CV) produced by optokinetic (OKN) motion: individual differences and effects of practice.

Science.gov (United States)

Kennedy, R S; Hettinger, L J; Harm, D L; Ordy, J M; Dunlap, W P

1996-01-01

Vection (V) refers to the compelling visual illusion of self-motion experienced by stationary individuals when viewing moving visual surrounds. The phenomenon is of theoretical interest because of its relevance for understanding the neural basis of ordinary self-motion perception, and of practical importance because it is the experience that makes simulation, virtual reality displays, and entertainment devices more vicarious. This experiment was performed to address whether an optokinetically induced vection illusion exhibits monotonic and stable psychometric properties and whether individuals differ reliably in these (V) perceptions. Subjects were exposed to varying velocities of the circular vection (CV) display in an optokinetic (OKN) drum 2 meters in diameter in 5 one-hour daily sessions extending over a 1 week period. For grouped data, psychophysical scalings of velocity estimates showed that exponents in a Stevens' type power function were essentially linear (slope = 0.95) and largely stable over sessions. Latencies were slightly longer for the slowest and fastest induction stimuli, and the trend over sessions for average latency was longer as a function of practice implying time course adaptation effects. Test-retest reliabilities for individual slope and intercept measures were moderately strong (r = 0.45) and showed no evidence of superdiagonal form. This implies stability of the individual circularvection (CV) sensitivities. Because the individual CV scores were stable, reliabilities were improved by averaging 4 sessions in order to provide a stronger retest reliability (r = 0.80). Individual latency responses were highly reliable (r = 0.80). Mean CV latency and motion sickness symptoms were greater in males than in females. These individual differences in CV could be predictive of other outcomes, such as susceptibility to disorientation or motion sickness, and for CNS localization of visual-vestibular interactions in the experience of self-motion.

Visualizing Stable Features in Live Cell Nucleus for Evaluation of the Cell Global Motion Compensation

Czech Academy of Sciences Publication Activity Database

Sorokin, D.V.; Suchánková, Jana; Bártová, Eva; Matula, P.

2014-01-01

Roč. 60, č. 1 (2014), s. 45-49 ISSN 0015-5500 R&D Projects: GA ČR GBP302/12/G157; GA MŠk(CZ) EE2.3.30.0030 Institutional support: RVO:68081707 Keywords : cell global motion compensation * UV laser bleaching * image registration Subject RIV: BO - Biophysics Impact factor: 1.000, year: 2014

Evolution of motion uncertainty in rectal cancer: implications for adaptive radiotherapy

Science.gov (United States)

Kleijnen, Jean-Paul J. E.; van Asselen, Bram; Burbach, Johannes P. M.; Intven, Martijn; Philippens, Marielle E. P.; Reerink, Onne; Lagendijk, Jan J. W.; Raaymakers, Bas W.

2016-01-01

Reduction of motion uncertainty by applying adaptive radiotherapy strategies depends largely on the temporal behavior of this motion. To fully optimize adaptive strategies, insight into target motion is needed. The purpose of this study was to analyze stability and evolution in time of motion uncertainty of both the gross tumor volume (GTV) and clinical target volume (CTV) for patients with rectal cancer. We scanned 16 patients daily during one week, on a 1.5 T MRI scanner in treatment position, prior to each radiotherapy fraction. Single slice sagittal cine MRIs were made at the beginning, middle, and end of each scan session, for one minute at 2 Hz temporal resolution. GTV and CTV motion were determined by registering a delineated reference frame to time-points later in time. The 95th percentile of observed motion (dist95%) was taken as a measure of motion. The stability of motion in time was evaluated within each cine-MRI separately. The evolution of motion was investigated between the reference frame and the cine-MRIs of a single scan session and between the reference frame and the cine-MRIs of several days later in the course of treatment. This observed motion was then converted into a PTV-margin estimate. Within a one minute cine-MRI scan, motion was found to be stable and small. Independent of the time-point within the scan session, the average dist95% remains below 3.6 mm and 2.3 mm for CTV and GTV, respectively 90% of the time. We found similar motion over time intervals from 18 min to 4 days. When reducing the time interval from 18 min to 1 min, a large reduction in motion uncertainty is observed. A reduction in motion uncertainty, and thus the PTV-margin estimate, of 71% and 75% for CTV and tumor was observed, respectively. Time intervals of 15 and 30 s yield no further reduction in motion uncertainty compared to a 1 min time interval.

Low-Cost High-Speed In-Plane Stroboscopic Micro-Motion Analyzer

Directory of Open Access Journals (Sweden)

Shashank S. Pandey

2017-11-01

Full Text Available Instrumentation for high-speed imaging and laser vibrometry is essential for the understanding and analysis of microstructure dynamics, but commercial instruments are largely unaffordable for most microelectromechanical systems (MEMS laboratories. We present the implementation of a very low cost in-plane micro motion stroboscopic analyzer that can be directly attached to a conventional probe station. The low-cost analyzer has been used to characterize the harmonic motion of 52.1 kHz resonating comb drive microactuators using ~50 ns pulsed light-emitting diode (LED stroboscope exposure times, producing sharp and high resolution (~0.5 μm device images at resonance, which rivals those of several orders of magnitude more expensive systems. This paper details the development of the high-speed stroboscopic imaging system and presents experimental results of motion analysis of example microstructures and a discussion of its operating limits. The system is shown to produce stable stroboscopic LED illumination to freeze device images up to 11 MHz.

Canonical algorithms for numerical integration of charged particle motion equations

Science.gov (United States)

Efimov, I. N.; Morozov, E. A.; Morozova, A. R.

2017-02-01

A technique for numerically integrating the equation of charged particle motion in a magnetic field is considered. It is based on the canonical transformations of the phase space in Hamiltonian mechanics. The canonical transformations make the integration process stable against counting error accumulation. The integration algorithms contain a minimum possible amount of arithmetics and can be used to design accelerators and devices of electron and ion optics.

Stable long-term chronic brain mapping at the single-neuron level.

Science.gov (United States)

Fu, Tian-Ming; Hong, Guosong; Zhou, Tao; Schuhmann, Thomas G; Viveros, Robert D; Lieber, Charles M

2016-10-01

Stable in vivo mapping and modulation of the same neurons and brain circuits over extended periods is critical to both neuroscience and medicine. Current electrical implants offer single-neuron spatiotemporal resolution but are limited by such factors as relative shear motion and chronic immune responses during long-term recording. To overcome these limitations, we developed a chronic in vivo recording and stimulation platform based on flexible mesh electronics, and we demonstrated stable multiplexed local field potentials and single-unit recordings in mouse brains for at least 8 months without probe repositioning. Properties of acquired signals suggest robust tracking of the same neurons over this period. This recording and stimulation platform allowed us to evoke stable single-neuron responses to chronic electrical stimulation and to carry out longitudinal studies of brain aging in freely behaving mice. Such advantages could open up future studies in mapping and modulating changes associated with learning, aging and neurodegenerative diseases.

Modeling anomalous diffusion by a subordinated fractional Lévy-stable process

International Nuclear Information System (INIS)

Teuerle, Marek; Wyłomańska, Agnieszka; Sikora, Grzegorz

2013-01-01

Two phenomena that can be discovered in systems with anomalous diffusion are long-range dependence and trapping events. The first effect concerns events that are arbitrarily distant but still influence each other exceptionally strongly, which is characteristic for anomalous regimes. The second corresponds to the presence of constant values of the underlying process. Motivated by the relatively poor class of models that can cover these two phenomena, we introduce subordinated fractional Lévy-stable motion with tempered stable waiting times. We present in detail its main properties, propose a simulation scheme and give an estimation procedure for its parameters. The last part of the paper is a presentation, via the Monte Carlo approach, of the effectiveness of the estimation of the parameters. (paper)

Biomechanical investigation of an alternative concept to angular stable plating using conventional fixation hardware.

Science.gov (United States)

Windolf, Markus; Klos, Kajetan; Wähnert, Dirk; van der Pol, Bas; Radtke, Roman; Schwieger, Karsten; Jakob, Roland P

2010-05-21

Angle-stable locking plates have improved the surgical management of fractures. However, locking implants are costly and removal can be difficult. The aim of this in vitro study was to evaluate the biomechanical performance of a newly proposed crossed-screw concept ("Fence") utilizing conventional (non-locked) implants in comparison to conventional LC-DCP (limited contact dynamic compression plate) and LCP (locking compression plate) stabilization, in a human cadaveric diaphyseal gap model. In eight pairs of human cadaveric femora, one femur per pair was randomly assigned to receive a Fence construct with either elevated or non-elevated plate, while the contralateral femur received either an LCP or LC-DCP instrumentation. Fracture gap motion and fatigue performance under cyclic loading was evaluated successively in axial compression and in torsion. Results were statistically compared in a pairwise setting. The elevated Fence constructs allowed significantly higher gap motion compared to the LCP instrumentations (axial compression: p concept can be of interest in cases were angle-stable implants are unavailable and can lead to new strategies in implant design.

Motion of the esophagus due to cardiac motion.

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Jacob Palmer

Full Text Available When imaging studies (e.g. CT are used to quantify morphological changes in an anatomical structure, it is necessary to understand the extent and source of motion which can give imaging artifacts (e.g. blurring or local distortion. The objective of this study was to assess the magnitude of esophageal motion due to cardiac motion. We used retrospective electrocardiogram-gated contrast-enhanced computed tomography angiography images for this study. The anatomic region from the carina to the bottom of the heart was taken at deep-inspiration breath hold with the patients' arms raised above their shoulders, in a position similar to that used for radiation therapy. The esophagus was delineated on the diastolic phase of cardiac motion, and deformable registration was used to sequentially deform the images in nearest-neighbor phases among the 10 cardiac phases, starting from the diastolic phase. Using the 10 deformation fields generated from the deformable registration, the magnitude of the extreme displacements was then calculated for each voxel, and the mean and maximum displacement was calculated for each computed tomography slice for each patient. The average maximum esophageal displacement due to cardiac motion for all patients was 5.8 mm (standard deviation: 1.6 mm, maximum: 10.0 mm in the transverse direction. For 21 of 26 patients, the largest esophageal motion was found in the inferior region of the heart; for the other patients, esophageal motion was approximately independent of superior-inferior position. The esophagus motion was larger at cardiac phases where the electrocardiogram R-wave occurs. In conclusion, the magnitude of esophageal motion near the heart due to cardiac motion is similar to that due to other sources of motion, including respiratory motion and intra-fraction motion. A larger cardiac motion will result into larger esophagus motion in a cardiac cycle.

Biomechanical investigation of an alternative concept to angular stable plating using conventional fixation hardware

Directory of Open Access Journals (Sweden)

Radtke Roman

2010-05-01

Full Text Available Abstract Background Angle-stable locking plates have improved the surgical management of fractures. However, locking implants are costly and removal can be difficult. The aim of this in vitro study was to evaluate the biomechanical performance of a newly proposed crossed-screw concept ("Fence" utilizing conventional (non-locked implants in comparison to conventional LC-DCP (limited contact dynamic compression plate and LCP (locking compression plate stabilization, in a human cadaveric diaphyseal gap model. Methods In eight pairs of human cadaveric femora, one femur per pair was randomly assigned to receive a Fence construct with either elevated or non-elevated plate, while the contralateral femur received either an LCP or LC-DCP instrumentation. Fracture gap motion and fatigue performance under cyclic loading was evaluated successively in axial compression and in torsion. Results were statistically compared in a pairwise setting. Results The elevated Fence constructs allowed significantly higher gap motion compared to the LCP instrumentations (axial compression: p ≤ 0.011, torsion p ≤ 0.015 but revealed similar performance under cyclic loading (p = 0.43. The Fence instrumentation with established bone-plate contact revealed larger fracture gap motion under axial compression compared to the conventional LC-DCP osteosynthesis (p ≤ 0.017. However, all contact Fence specimens survived the cyclic test, whereas all LC-DCP constructs failed early during torsion testing (p Conclusions Even though accentuated fracture gap motion became obvious, the "Fence" technique is considered an alternative to cost-intensive locking-head devices. The concept can be of interest in cases were angle-stable implants are unavailable and can lead to new strategies in implant design.

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

Ground Motion Prediction Trends For Eastern North America Based on the Next Generation Attenuation East Ground Motion Database

Science.gov (United States)

Cramer, C. H.; Kutliroff, J.; Dangkua, D.

2010-12-01

A five-year Next Generation Attenuation (NGA) East project to develop new ground motion prediction equations for stable continental regions (SCRs), including eastern North America (ENA), has begun at the Pacific Earthquake Engineering Research (PEER) Center funded by the Nuclear Regulatory Commission (NRC), the U.S. Geological Survey (USGS), the Electric Power Research Institute (EPRI), and the Department of Energy (DOE). The initial effort focused on database design and collection of appropriate M>4 ENA broadband and accelerograph records to populate the database. Ongoing work has focused on adding records from smaller ENA earthquakes and from other SCRs such as Europe, Australia, and India. Currently, over 6500 horizontal and vertical component records from 60 ENA earthquakes have been collected and prepared (instrument response removed, filtering to acceptable-signal band, determining peak and spectral parameter values, quality assurance, etc.) for the database. Geologic Survey of Canada (GSC) strong motion recordings, previously not available, have also been added to the NGA East database. The additional earthquakes increase the number of ground motion recordings in the 10 - 100 km range, particularly from the 2008 M5.2 Mt. Carmel, IL event, and the 2005 M4.7 Riviere du Loup and 2010 M5.0 Val des Bois earthquakes in Quebec, Canada. The goal is to complete the ENA database and make it available in 2011 followed by a SCR database in 2012. Comparisons of ground motion observations from four recent M5 ENA earthquakes with current ENA ground motion prediction equations (GMPEs) suggest that current GMPEs, as a group, reasonably agree with M5 observations at short periods, particularly at distances less than 200 km. However, at one second, current GMPEs over predict M5 ground motion observations. The 2001 M7.6 Bhuj, India, earthquake provides some constraint at large magnitudes, as geology and regional attenuation is analogous to ENA. Cramer and Kumar, 2003, have

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

Focal spot motion of linear accelerators and its effect on portal image analysis

NARCIS (Netherlands)

Sonke, Jan-Jakob; Brand, Bob; van Herk, Marcel

2003-01-01

The focal spot of a linear accelerator is often considered to have a fully stable position. In practice, however, the beam control loop of a linear accelerator needs to stabilize after the beam is turned on. As a result, some motion of the focal spot might occur during the start-up phase of

Complex motion in nonlinear-map model of elevators in energy-saving traffic

International Nuclear Information System (INIS)

Nagatani, Takashi

2011-01-01

We have studied the dynamic behavior and dynamic transitions of elevators in a system for reducing energy consumption. We present a nonlinear-map model for the dynamics of M elevators. The motion of elevators depends on the loading parameter and their number M. The dependence of the fixed points on the loading parameter is derived. The dynamic transitions occur at 2(M-1) stages with increasing the value of loading parameter. At the dynamic transition point, the motion of elevators changes from a stable state to an unstable state and vice versa. The elevators display periodic motions with various periods in the unstable state. In the unstable state, the number of riding passengers fluctuates in a complex manner over various trips. - Highlights: → We propose the nonlinear-map model in energy-saving traffic of elevators. → We study the dynamical behavior and dynamical transitions in the system of elevators. → We derive the fixed point of the nonlinear map analytically. → We clarify the dependence of the motion on the loading parameter and the number.

Complex motion in nonlinear-map model of elevators in energy-saving traffic

Energy Technology Data Exchange (ETDEWEB)

Nagatani, Takashi, E-mail: tmtnaga@ipc.shizuoka.ac.j [Department of Mechanical Engineering, Division of Thermal Science, Shizuoka University, Hamamatsu 432-8561 (Japan)

2011-05-16

We have studied the dynamic behavior and dynamic transitions of elevators in a system for reducing energy consumption. We present a nonlinear-map model for the dynamics of M elevators. The motion of elevators depends on the loading parameter and their number M. The dependence of the fixed points on the loading parameter is derived. The dynamic transitions occur at 2(M-1) stages with increasing the value of loading parameter. At the dynamic transition point, the motion of elevators changes from a stable state to an unstable state and vice versa. The elevators display periodic motions with various periods in the unstable state. In the unstable state, the number of riding passengers fluctuates in a complex manner over various trips. - Highlights: We propose the nonlinear-map model in energy-saving traffic of elevators. We study the dynamical behavior and dynamical transitions in the system of elevators. We derive the fixed point of the nonlinear map analytically. We clarify the dependence of the motion on the loading parameter and the number.

Estimating Vertical Land Motion in the Chesapeake Bay

Science.gov (United States)

Houttuijn Bloemendaal, L.; Hensel, P.

2017-12-01

This study aimed to provide a modern measurement of subsidence in the Chesapeake Bay region and establish a methodology for measuring vertical land motion using static GPS, a cheaper alternative to InSAR or classical leveling. Vertical land motion in this area is of particular concern because tide gages are showing up to 5 mm/yr of local, relative sea level rise. While a component of this rate is the actual eustatic sea level rise itself, part of the trend may also be vertical land motion, in which subsidence exacerbates the effects of actual changes in sea level. Parts of this region are already experiencing an increase in the frequency and magnitude of near-shore coastal flooding, but the last comprehensive study of vertical land motion in this area was conducted by NOAA in 1974 (Holdahl & Morrison) using repeat leveled lines. More recent measures of vertical land motion can help inform efforts on resilience to sea level rise, such as in the Hampton Roads area. This study used measured GPS-derived vertical heights in conjunction with legacy GPS data to calculate rates of vertical motion at several points in time for a selection of benchmarks scattered throughout the region. Seventeen marks in the stable Piedmont area and in the areas suspected of subsidence in the Coastal Plain were selected for the analysis. Results indicate a significant difference between the rates of vertical motion in the Piedmont and Coastal Plain, with a mean rate of -4.10 mm/yr in the Coastal Plain and 0.15 mm/yr in the Piedmont. The rates indicate particularly severe subsidence at the southern Delmarva Peninsula coast and the Hampton-Roads area, with a mean rate of -6.57 mm/yr in that region. By knowing local rates of subsidence as opposed to sea level change itself, coastal managers may make better informed decisions regarding natural resource use, such as deciding whether or not to reduce subsurface fluid withdrawals or to consider injecting treated water back into the aquifer to slow

Optimal Control of Holding Motion by Nonprehensile Two-Cooperative-Arm Robot

Directory of Open Access Journals (Sweden)

Changan Jiang

2016-01-01

Full Text Available Recently, more researchers have focused on nursing-care assistant robot and placed their hope on it to solve the shortage problem of the caregivers in hospital or nursing home. In this paper, a nonprehensile two-cooperative-arm robot is considered to realize holding motion to keep a two-rigid-link object (regarded as a care-receiver stable on the robot arms. By applying Newton-Euler equations of motion, dynamic model of the object is obtained. In this model, for describing interaction behavior between object and robot arms in the normal direction, a viscoelastic model is employed to represent the normal forces. Considering existence of friction between object and robot arms, LuGre dynamic model is applied to describe the friction. Based on the obtained model, an optimal regulator is designed to control the holding motion of two-cooperative-arm robot. In order to verify the effectiveness of the proposed method, simulation results are shown.

Stable Flocking of Multiple Agents Based on Molecular Potential Field and Distributed Receding Horizon Control

International Nuclear Information System (INIS)

Zhang Yun-Peng; Duan Hai-Bin; Zhang Xiang-Yin

2011-01-01

A novel distributed control scheme to generate stable flocking motion for a group of agents is proposed. In this control scheme, a molecular potential field model is applied as the potential field function because of its smoothness and unique shape. The approach of distributed receding horizon control is adopted to drive each agent to find its optimal control input to lower its potential at every step. Experimental results show that this proposed control scheme can ensure that all agents eventually converge to a stable flocking formation with a common velocity and the collisions can also be avoided at the same time. (general)

A mechanical energy harvested magnetorheological damper with linear-rotary motion converter

Science.gov (United States)

Chu, Ki Sum; Zou, Li; Liao, Wei-Hsin

2016-04-01

Magnetorheological (MR) dampers are promising to substitute traditional oil dampers because of adaptive properties of MR fluids. During vibration, significant energy is wasted due to the energy dissipation in the damper. Meanwhile, for conventional MR damping systems, extra power supply is needed. In this paper, a new energy harvester is designed in an MR damper that integrates controllable damping and energy harvesting functions into one device. The energy harvesting part of this MR damper has a unique mechanism converting linear motion to rotary motion that would be more stable and cost effective when compared to other mechanical transmissions. A Maxon motor is used as a power generator to convert the mechanical energy into electrical energy to supply power for the MR damping system. Compared to conventional approaches, there are several advantages in such an integrated device, including weight reduction, ease in installation with less maintenance. A mechanical energy harvested MR damper with linear-rotary motion converter and motion rectifier is designed, fabricated, and tested. Experimental studies on controllable damping force and harvested energy are performed with different transmissions. This energy harvesting MR damper would be suitable to vehicle suspensions, civil structures, and smart prostheses.

Piezo-based motion stages for heavy duty operation in clean environments

Science.gov (United States)

Karasikov, Nir; Peled, Gal; Yasinov, Roman; Gissin, Michael; Feinstein, Alan

2018-02-01

A range of heavy duty, ultra-precise motion stages had been developed for precise positioning in semiconductor manufacturing and metrology, for use in a clean room and high vacuum (HV and UHV) environments, to meet the precision requirements for 7, 5 nm nodes and beyond. These stages are powered by L1B2 direct drive ultrasonic motors, which allows combining long motion range, sub-nanometer positioning accuracy, high stiffness (in the direction of motion), low power consumption and active compensation of thermal and structural drift while holding position. The mechanical design, material selection for clean room and high vacuum preparation techniques are reviewed. Test results in a clean room are reported for a two-axis (X-Y) stage, having a load capacity of 30 kg, a motion range of 450 mm, a positioning accuracy of 200 mm/s and a profile has a trapezoidal shape with an acceleration of 1m/s2 and a constant velocity of 100 mm/s. The operational parameters (average absolute position error during constant velocity, motor force, dead zone level) remain stable over more than 370000 passes (experiment duration).

The Role of Motion Concepts in Understanding Non-Motion Concepts

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Omid Khatin-Zadeh

2017-12-01

Full Text Available This article discusses a specific type of metaphor in which an abstract non-motion domain is described in terms of a motion event. Abstract non-motion domains are inherently different from concrete motion domains. However, motion domains are used to describe abstract non-motion domains in many metaphors. Three main reasons are suggested for the suitability of motion events in such metaphorical descriptions. Firstly, motion events usually have high degrees of concreteness. Secondly, motion events are highly imageable. Thirdly, components of any motion event can be imagined almost simultaneously within a three-dimensional space. These three characteristics make motion events suitable domains for describing abstract non-motion domains, and facilitate the process of online comprehension throughout language processing. Extending the main point into the field of mathematics, this article discusses the process of transforming abstract mathematical problems into imageable geometric representations within the three-dimensional space. This strategy is widely used by mathematicians to solve highly abstract and complex problems.

Solutions of the Strominger System via Stable Bundles on Calabi-Yau Threefolds

DEFF Research Database (Denmark)

Andreas, Björn; Garcia Fernandez, Mario

2012-01-01

We prove that a given Calabi-Yau threefold with a stable holomorphic vector bundle can be perturbed to a solution of the Strominger system provided that the second Chern class of the vector bundle is equal to the second Chern class of the tangent bundle. If the Calabi-Yau threefold has strict SU(......) holonomy then the equations of motion derived from the heterotic string effective action are also satisfied by the solutions we obtain....

A Motion Planning Method for Omnidirectional Mobile Robot Based on the Anisotropic Characteristics

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Chuntao Leng

2008-11-01

Full Text Available A more suitable motion planning method for an omni-directional mobile robot (OMR, an improved APF method (iAPF, is proposed in this paper by introducing the revolving factor into the artificial potential field (APF. Accordingly, the motion direction derived from traditional artificial potential field (tAPF is regulated. The maximum velocity, maximum acceleration and energy consumption of the OMR moving in different directions are analyzed, based on the kinematic and dynamic constraints of an OMR, and the anisotropy of OMR is presented in this paper. Then the novel concept of an Anisotropic-Function is proposed to indicate the quality of motion in different directions, which can make a very favorable trade-off between time-optimality, stability and efficacy-optimality. In order to obtain the optimal motion, the path that the robot can take in order to avoid the obstacle safely and reach the goal in a shorter path is deduced. Finally, simulations and experiments are carried out to demonstrate that the motion resulting from the iAPF is high-speed, highly stable and highly efficient when compared to the tAPF.

Non-Gaussian distributions of melodic intervals in music: The Lévy-stable approximation

Science.gov (United States)

Niklasson, Gunnar A.; Niklasson, Maria H.

2015-11-01

The analysis of structural patterns in music is of interest in order to increase our fundamental understanding of music, as well as for devising algorithms for computer-generated music, so called algorithmic composition. Musical melodies can be analyzed in terms of a “music walk” between the pitches of successive tones in a notescript, in analogy with the “random walk” model commonly used in physics. We find that the distribution of melodic intervals between tones can be approximated with a Lévy-stable distribution. Since music also exibits self-affine scaling, we propose that the “music walk” should be modelled as a Lévy motion. We find that the Lévy motion model captures basic structural patterns in classical as well as in folk music.

Insights into Ground-Motion Processes from Intensity Data (Invited)

Science.gov (United States)

Atkinson, G. M.

2009-12-01

Analysis of intensity data gathered from the on-line “Did You Feel It?” (DYFI) questionnaire program (Wald et al., 1999, Seism. Res. L.) provides new insights into both contemporary and historical ground-motion processes; this is particularly important for sparsely-instrumented regions. The value of the DYFI data lies in their vast quantities and large spatial coverage. With thousands to tens of thousands of respondents providing information on the felt and damage characteristics of widely-felt earthquakes, DYFI intensity data provide surprisingly high resolution of ground-motion features. The large data quantities allow techniques such as binning to be used to bring out these features in a statistically-stable way (Atkinson and Wald, 2007, Seism. Res. L.), while correlations of the statistics of DYFI intensities with instrumental ground motions provide the link between intensity and engineering ground-motion parameters (Wald et al., 1999, Earthquake Spectra). This link is largely independent of region if its dependence on earthquake magnitude and distance is taken into account (Kaka and Atkinson, 2007, BSSA). Thus DYFI data provide a valuable tool with which ground motions can be estimated, if their felt and damage effects have been reported. This is useful both for understanding contemporary events in sparsely-instrumented regions, and for re-evaluating historical events, for which only intensity data are available. By using calibrated intensity observations, a number of ground-motion processes can be investigated based on DYFI and/or historical intensity data. For example, intensity data shed light on source scaling issues, and whether source parameters vary regionally. They can also be used to document regional attenuation features, such as the attenuation rate and its variation with distance (Atkinson and Wald, 2007). A key uncertainty in these investigations concerns the effect of spectral shape on intensity; the spectral shape is influenced by site

Stable convergence and stable limit theorems

CERN Document Server

Häusler, Erich

2015-01-01

The authors present a concise but complete exposition of the mathematical theory of stable convergence and give various applications in different areas of probability theory and mathematical statistics to illustrate the usefulness of this concept. Stable convergence holds in many limit theorems of probability theory and statistics – such as the classical central limit theorem – which are usually formulated in terms of convergence in distribution. Originated by Alfred Rényi, the notion of stable convergence is stronger than the classical weak convergence of probability measures. A variety of methods is described which can be used to establish this stronger stable convergence in many limit theorems which were originally formulated only in terms of weak convergence. Naturally, these stronger limit theorems have new and stronger consequences which should not be missed by neglecting the notion of stable convergence. The presentation will be accessible to researchers and advanced students at the master's level...

Dynamics of the retrograde 1/1 mean motion resonance

Science.gov (United States)

Huang, Yukun; Li, Miao; Li, Junfeng; Gong, Shengping

2018-04-01

Mean motion resonances are very common in the solar system. Asteroids in mean motion resonances with giant planets have been studied for centuries. But it was not until recently that asteroids in retrograde mean motion resonances with Jupiter and Saturn were discovered. The newly discovered asteroid, 2015 BZ509 is confirmed to be the first asteroid in retrograde 1:1 mean motion resonance (or retrograde co-orbital resonance) with Jupiter, which gives rise to our interests in its unique resonant dynamics. In this study, we thoroughly investigate the phase-space structure of the retrograde 1:1 resonance within the framework of the circular restricted three-body problem. We begin by constructing a simple integrable approximation for the planar retrograde resonance with the Hamiltonian approach and show that the variables definition of the retrograde resonance is very different to the prograde one. When it comes to the disturbing function, we abandon the classical series expansion approach, whereas numerically carry out the averaging process on the disturbing function in closed form. The phase portrait of the retrograde 1:1 resonance is depicted with the level curves of the averaged Hamiltonian. We find that the topological structure of phase space for the retrograde 1:1 resonance is very different to other resonances, due to the consistent existence of the collision separatrix. And the surprising bifurcation of equilibrium point around 180° (i.e., the apocentric libration center) has never been found in any other mean motion resonances before. We thoroughly analyze the novel apocentric librations and find that close encounter with the planet does not always lead to the disruption of a stable apocentric libration. Afterwards, we examine the Kozai dynamics inside the mean motion resonance with the similar Hamiltonian approach and explain why the exact resonant point does not exist in the 3D retrograde 1:1 resonance model.

Early Site Permit Demonstration Program: Guidelines for determining design basis ground motions

International Nuclear Information System (INIS)

1993-01-01

This report develops and applies a methodology for estimating strong earthquake ground motion. The motivation was to develop a much needed tool for use in developing the seismic requirements for structural designs. An earthquake's ground motion is a function of the earthquake's magnitude, and the physical properties of the earth through which the seismic waves travel from the earthquake fault to the site of interest. The emphasis of this study is on ground motion estimation in Eastern North America (east of the Rocky Mountains), with particular emphasis on the Eastern United States and southeastern Canada. Eastern North America is a stable continental region, having sparse earthquake activity with rare occurrences of large earthquakes. While large earthquakes are of interest for assessing seismic hazard, little data exists from the region to empirically quantify their effects. The focus of the report is on the attributes of ground motion in Eastern North America that are of interest for the design of facilities such as nuclear power plants. This document, Volume II, contains Appendices 2, 3, 5, 6, and 7 covering the following topics: Eastern North American Empirical Ground Motion Data; Examination of Variance of Seismographic Network Data; Soil Amplification and Vertical-to-Horizontal Ratios from Analysis of Strong Motion Data From Active Tectonic Regions; Revision and Calibration of Ou and Herrmann Method; Generalized Ray Procedure for Modeling Ground Motion Attenuation; Crustal Models for Velocity Regionalization; Depth Distribution Models; Development of Generic Site Effects Model; Validation and Comparison of One-Dimensional Site Response Methodologies; Plots of Amplification Factors; Assessment of Coupling Between Vertical ampersand Horizontal Motions in Nonlinear Site Response Analysis; and Modeling of Dynamic Soil Properties

Trochanteric fracture-implant motion during healing - A radiostereometry (RSA) study.

Science.gov (United States)

Bojan, Alicja J; Jönsson, Anders; Granhed, Hans; Ekholm, Carl; Kärrholm, Johan

2018-03-01

Cut-out complication remains a major unsolved problem in the treatment of trochanteric hip fractures. A better understanding of the three-dimensional fracture-implant motions is needed to enable further development of clinical strategies and countermeasures. The aim of this clinical study was to characterise and quantify three-dimensional motions between the implant and the bone and between the lag screw and nail of the Gamma nail. Radiostereometry Analysis (RSA) analysis was applied in 20 patients with trochanteric hip fractures treated with an intramedullary nail. The following three-dimensional motions were measured postoperatively, at 1 week, 3, 6 and 12 months: translations of the tip of the lag screw in the femoral head, motions of the lag screw in the nail, femoral head motions relative to the nail and nail movements in the femoral shaft. Cranial migration of the tip of the lag screw dominated over the other two translation components in the femoral head. In all fractures the lag screw slid laterally in the nail and the femoral head moved both laterally and inferiorly towards the nail. All femoral heads translated posteriorly relative to the nail, and rotations occurred in both directions with median values close to zero. The nail tended to retrovert in the femoral shaft. Adverse fracture-implant motions were detected in stable trochanteric hip fractures treated with intramedullary nails with high resolution. Therefore, RSA method can be used to evaluate new implant designs and clinical strategies, which aim to reduce cut-out complications. Future RSA studies should aim at more unstable fractures as these are more likely to fail with cut-out. Copyright © 2018 Elsevier Ltd. All rights reserved.

Ultraprecision XY stage using a hybrid bolt-clamped Langevin-type ultrasonic linear motor for continuous motion.

Science.gov (United States)

Lee, Dong-Jin; Lee, Sun-Kyu

2015-01-01

This paper presents a design and control system for an XY stage driven by an ultrasonic linear motor. In this study, a hybrid bolt-clamped Langevin-type ultrasonic linear motor was manufactured and then operated at the resonance frequency of the third longitudinal and the sixth lateral modes. These two modes were matched through the preload adjustment and precisely tuned by the frequency matching method based on the impedance matching method with consideration of the different moving weights. The XY stage was evaluated in terms of position and circular motion. To achieve both fine and stable motion, the controller consisted of a nominal characteristics trajectory following (NCTF) control for continuous motion, dead zone compensation, and a switching controller based on the different NCTFs for the macro- and micro-dynamics regimes. The experimental results showed that the developed stage enables positioning and continuous motion with nanometer-level accuracy.

Focal spot motion of linear accelerators and its effect on portal image analysis

International Nuclear Information System (INIS)

Sonke, Jan-Jakob; Brand, Bob; Herk, Marcel van

2003-01-01

The focal spot of a linear accelerator is often considered to have a fully stable position. In practice, however, the beam control loop of a linear accelerator needs to stabilize after the beam is turned on. As a result, some motion of the focal spot might occur during the start-up phase of irradiation. When acquiring portal images, this motion will affect the projected position of anatomy and field edges, especially when low exposures are used. In this paper, the motion of the focal spot and the effect of this motion on portal image analysis are quantified. A slightly tilted narrow slit phantom was placed at the isocenter of several linear accelerators and images were acquired (3.5 frames per second) by means of an amorphous silicon flat panel imager positioned ∼0.7 m below the isocenter. The motion of the focal spot was determined by converting the tilted slit images to subpixel accurate line spread functions. The error in portal image analysis due to focal spot motion was estimated by a subtraction of the relative displacement of the projected slit from the relative displacement of the field edges. It was found that the motion of the focal spot depends on the control system and design of the accelerator. The shift of the focal spot at the start of irradiation ranges between 0.05-0.7 mm in the gun-target (GT) direction. In the left-right (AB) direction the shift is generally smaller. The resulting error in portal image analysis due to focal spot motion ranges between 0.05-1.1 mm for a dose corresponding to two monitor units (MUs). For 20 MUs, the effect of the focal spot motion reduces to 0.01-0.3 mm. The error in portal image analysis due to focal spot motion can be reduced by reducing the applied dose rate

Measurement of spin motions in a storage ring outside the stable polarization direction

International Nuclear Information System (INIS)

Akchurin, N.; McPherson, J.; Olchowski, F.; Onel, Y.; Badano, L.; Conte, M.; Bravar, A.; Penzo, A.; Hall, J.; Kreiser, H.

1993-01-01

Polarized, stored beams are becoming a more and more important tool in nuclear and high energy physics. In order to measure the beam polarization in a storage ring the polarization vector of the stored beam has to aim, revolution for revolution, over a period of seconds to minutes, into the same, so-called open-quote stableclose quotes, direction. In this paper measurements at the Indiana University Cooler Ring (IUCF) are described in which for the first time in a storage ring oscillations of the polarization vector around this stable direction have been measured. The existence and the dynamics of such oscillations are, for instance, important for a new proposed technique for polarizing stored hadron beams

Deficient Biological Motion Perception in Schizophrenia: Results from a Motion Noise Paradigm

Directory of Open Access Journals (Sweden)

Jejoong eKim

2013-07-01

Full Text Available Background: Schizophrenia patients exhibit deficient processing of perceptual and cognitive information. However, it is not well understood how basic perceptual deficits contribute to higher level cognitive problems in this mental disorder. Perception of biological motion, a motion-based cognitive recognition task, relies on both basic visual motion processing and social cognitive processing, thus providing a useful paradigm to evaluate the potentially hierarchical relationship between these two levels of information processing. Methods: In this study, we designed a biological motion paradigm in which basic visual motion signals were manipulated systematically by incorporating different levels of motion noise. We measured the performances of schizophrenia patients (n=21 and healthy controls (n=22 in this biological motion perception task, as well as in coherent motion detection, theory of mind, and a widely used biological motion recognition task. Results: Schizophrenia patients performed the biological motion perception task with significantly lower accuracy than healthy controls when perceptual signals were moderately degraded by noise. A more substantial degradation of perceptual signals, through using additional noise, impaired biological motion perception in both groups. Performance levels on biological motion recognition, coherent motion detection and theory of mind tasks were also reduced in patients. Conclusion: The results from the motion-noise biological motion paradigm indicate that in the presence of visual motion noise, the processing of biological motion information in schizophrenia is deficient. Combined with the results of poor basic visual motion perception (coherent motion task and biological motion recognition, the association between basic motion signals and biological motion perception suggests a need to incorporate the improvement of visual motion perception in social cognitive remediation.

Angular Stable Miniplate Fixation of Chronic Unstable Scaphoid Nonunion.

Science.gov (United States)

Schormans, Philip M J; Brink, Peter R G; Poeze, Martijn; Hannemann, Pascal F W

2018-02-01

Background  Around 5 to 15% of all scaphoid fractures result in nonunion. Treatment of long-lasting scaphoid nonunion remains a challenge for the treating surgeon. Healing of scaphoid nonunion is essential for prevention of scaphoid nonunion advanced collapse and the subsequent predictable pattern of radiocarpal osteoarthritis. Purpose  The purpose of this study was to investigate the feasibility of fixation of the scaphoid nonunion with a volar angular stable miniplate and cancellous bone grafting. We hypothesized that this technique could be successful, even in patients with previous surgery for nonunion and in patients with a long duration of nonunion. Patients and Methods  A total of 21 patients enrolled in a single-center prospective cohort study. Healing of nonunion was assessed on multiplanar computed tomography scan of the wrist at a 3-month interval. Functional outcome was assessed by measuring grip strength, range of motion, and by means of the patient-rated wrist and hand evaluation (PRWHE) questionnaire. Results  During follow-up, 19 out of 21 patients (90%) showed radiological healing of the nonunion. The range of motion did not improve significantly. Postoperative PRWHE scores decreased by 34 points. Healing occurred regardless of the length of time of the nonunion (range: 6-183 months) and regardless of previous surgery (38% of patients). Conclusion  Volar angular stable miniplate fixation with autologous cancellous bone grafting is a successful technique for the treatment of chronic unstable scaphoid nonunion, even in patients with long-lasting nonunion and in patients who underwent previous surgery for a scaphoid fracture. Rotational interfragmentary stability might be an important determining factor for the successful treatment of unstable scaphoid nonunion. Level of Evidence  Level IV.

Stability of submerged rock berms exposed to motion of liquefied soil in waves

DEFF Research Database (Denmark)

Sumer, B. Mutlu; Dixen, Figen Hatipoglu; Fredsøe, Jørgen

2011-01-01

. Various berm materials were used, stones of size 0.74–2.5cm, plastic balls of size 3.6cm, brass of size 2.5cm and steel of size 1.0cm. The experiments show that rock berms that are stable under very large waves can be unstable when they are exposed to the motion of liquefied soil. The limited data......The paper describes the results of an experimental study on the behaviour of a submerged rock berm in liquefied backfill soil. The soil is liquefied by waves, and the rock berm is subject to the orbital motion of the liquefied soil. The soil used in the experiments was silt with d50=0.075mm...

Measurement of shoulder motion fraction and motion ratio

International Nuclear Information System (INIS)

Kang, Yeong Han

2006-01-01

This study was to understand about the measurement of shoulder motion fraction and motion ratio. We proposed the radiological criterior of glenohumeral and scapulothoracic movement ratio. We measured the motion fraction of the glenohumeral and scapulothoracic movement using CR (computed radiological system) of arm elevation at neutral, 90 degree, full elevation. Central ray was 15 .deg., 19 .deg., 22 .deg. to the cephald for the parallel scapular spine, and the tilting of torso was external oblique 40 .deg., 36 .deg., 22 .deg. for perpendicular to glenohumeral surface. Healthful donor of 100 was divided 5 groups by age (20, 30, 40, 50, 60). The angle of glenohumeral motion and scapulothoracic motion could be taken from gross arm angle and radiological arm angle. We acquired 3 images at neutral, 90 .deg. and full elevation position and measured radiographic angle of glenoheumeral, scapulothoracic movement respectively. While the arm elevation was 90 .deg., the shoulder motion fraction was 1.22 (M), 1.70 (W) in right arm and 1.31, 1.54 in left. In full elevation, Right arm fraction was 1.63, 1.84 and left was 1.57, 1.32. In right dominant arm (78%), 90 .deg. and Full motion fraction was 1.58, 1.43, in left (22%) 1.82, 1.94. In generation 20, 90 .deg. and Full motion fraction was 1.56, 1.52, 30' was 1.82, 1.43, 40' was 1.23, 1.16, 50' was 1.80, 1.28,60' was 1.24, 1.75. There was not significantly by gender, dominant arm and age. The criteria of motion fraction was useful reference for clinical diagnosis the shoulder instability

Dynamic Portrait of the Retrograde 1:1 Mean Motion Resonance

Science.gov (United States)

Huang, Yukun; Li, Miao; Li, Junfeng; Gong, Shengping

2018-06-01

Asteroids in mean motion resonances with giant planets are common in the solar system, but it was not until recently that several asteroids in retrograde mean motion resonances with Jupiter and Saturn were discovered. A retrograde co-orbital asteroid of Jupiter, 2015 BZ509 is confirmed to be in a long-term stable retrograde 1:1 mean motion resonance with Jupiter, which gives rise to our interests in its unique resonant dynamics. In this paper, we investigate the phase-space structure of the retrograde 1:1 resonance in detail within the framework of the circular restricted three-body problem. We construct a simple integrable approximation for the planar retrograde resonance using canonical contact transformation and numerically employ the averaging procedure in closed form. The phase portrait of the retrograde 1:1 resonance is depicted with the level curves of the averaged Hamiltonian. We thoroughly analyze all possible librations in the co-orbital region and uncover a new apocentric libration for the retrograde 1:1 resonance inside the planet’s orbit. We also observe the significant jumps in orbital elements for outer and inner apocentric librations, which are caused by close encounters with the perturber.

Markerless motion estimation for motion-compensated clinical brain imaging

Science.gov (United States)

Kyme, Andre Z.; Se, Stephen; Meikle, Steven R.; Fulton, Roger R.

2018-05-01

Motion-compensated brain imaging can dramatically reduce the artifacts and quantitative degradation associated with voluntary and involuntary subject head motion during positron emission tomography (PET), single photon emission computed tomography (SPECT) and computed tomography (CT). However, motion-compensated imaging protocols are not in widespread clinical use for these modalities. A key reason for this seems to be the lack of a practical motion tracking technology that allows for smooth and reliable integration of motion-compensated imaging protocols in the clinical setting. We seek to address this problem by investigating the feasibility of a highly versatile optical motion tracking method for PET, SPECT and CT geometries. The method requires no attached markers, relying exclusively on the detection and matching of distinctive facial features. We studied the accuracy of this method in 16 volunteers in a mock imaging scenario by comparing the estimated motion with an accurate marker-based method used in applications such as image guided surgery. A range of techniques to optimize performance of the method were also studied. Our results show that the markerless motion tracking method is highly accurate (brain imaging and holds good promise for a practical implementation in clinical PET, SPECT and CT systems.

PET motion correction using PRESTO with ITK motion estimation

Energy Technology Data Exchange (ETDEWEB)

Botelho, Melissa [Institute of Biophysics and Biomedical Engineering, Science Faculty of University of Lisbon (Portugal); Caldeira, Liliana; Scheins, Juergen [Institute of Neuroscience and Medicine (INM-4), Forschungszentrum Jülich (Germany); Matela, Nuno [Institute of Biophysics and Biomedical Engineering, Science Faculty of University of Lisbon (Portugal); Kops, Elena Rota; Shah, N Jon [Institute of Neuroscience and Medicine (INM-4), Forschungszentrum Jülich (Germany)

2014-07-29

The Siemens BrainPET scanner is a hybrid MRI/PET system. PET images are prone to motion artefacts which degrade the image quality. Therefore, motion correction is essential. The library PRESTO converts motion-corrected LORs into highly accurate generic projection data [1], providing high-resolution PET images. ITK is an open-source software used for registering multidimensional data []. ITK provides motion estimation necessary to PRESTO.

PET motion correction using PRESTO with ITK motion estimation

International Nuclear Information System (INIS)

Botelho, Melissa; Caldeira, Liliana; Scheins, Juergen; Matela, Nuno; Kops, Elena Rota; Shah, N Jon

2014-01-01

The Siemens BrainPET scanner is a hybrid MRI/PET system. PET images are prone to motion artefacts which degrade the image quality. Therefore, motion correction is essential. The library PRESTO converts motion-corrected LORs into highly accurate generic projection data [1], providing high-resolution PET images. ITK is an open-source software used for registering multidimensional data []. ITK provides motion estimation necessary to PRESTO.

Neurons in cortical area MST remap the memory trace of visual motion across saccadic eye movements.

Science.gov (United States)

Inaba, Naoko; Kawano, Kenji

2014-05-27

Perception of a stable visual world despite eye motion requires integration of visual information across saccadic eye movements. To investigate how the visual system deals with localization of moving visual stimuli across saccades, we observed spatiotemporal changes of receptive fields (RFs) of motion-sensitive neurons across periods of saccades in the middle temporal (MT) and medial superior temporal (MST) areas. We found that the location of the RFs moved with shifts of eye position due to saccades, indicating that motion-sensitive neurons in both areas have retinotopic RFs across saccades. Different characteristic responses emerged when the moving visual stimulus was turned off before the saccades. For MT neurons, virtually no response was observed after the saccade, suggesting that the responses of these neurons simply reflect the reafferent visual information. In contrast, most MST neurons increased their firing rates when a saccade brought the location of the visual stimulus into their RFs, where the visual stimulus itself no longer existed. These findings suggest that the responses of such MST neurons after saccades were evoked by a memory of the stimulus that had preexisted in the postsaccadic RFs ("memory remapping"). A delayed-saccade paradigm further revealed that memory remapping in MST was linked to the saccade itself, rather than to a shift in attention. Thus, the visual motion information across saccades was integrated in spatiotopic coordinates and represented in the activity of MST neurons. This is likely to contribute to the perception of a stable visual world in the presence of eye movements.

Motion control report

CERN Document Server

2013-01-01

Please note this is a short discount publication. In today's manufacturing environment, Motion Control plays a major role in virtually every project.The Motion Control Report provides a comprehensive overview of the technology of Motion Control:* Design Considerations* Technologies* Methods to Control Motion* Examples of Motion Control in Systems* A Detailed Vendors List

Effect of stable stratification on dispersion within urban street canyons: A large-eddy simulation

Science.gov (United States)

Li, Xian-Xiang; Britter, Rex; Norford, Leslie K.

2016-11-01

This study employs a validated large-eddy simulation (LES) code with high tempo-spatial resolution to investigate the effect of a stably stratified roughness sublayer (RSL) on scalar transport within an urban street canyon. The major effect of stable stratification on the flow and turbulence inside the street canyon is that the flow slows down in both streamwise and vertical directions, a stagnant area near the street level emerges, and the vertical transport of momentum is weakened. Consequently, the transfer of heat between the street canyon and overlying atmosphere also gets weaker. The pollutant emitted from the street level 'pools' within the lower street canyon, and more pollutant accumulates within the street canyon with increasing stability. Under stable stratification, the dominant mechanism for pollutant transport within the street canyon has changed from ejections (flow carries high-concentration pollutant upward) to unorganized motions (flow carries high-concentration pollutant downward), which is responsible for the much lower dispersion efficiency under stable stratifications.

Vibration Energy Harvester with Bi-stable Curved Beam Spring Offset by Gravitational Acceleration

International Nuclear Information System (INIS)

Yamamoto, Koki; Fujita, Takayuki; Kanda, Kensuke; Maenaka, Kazusuke; Badel, Adrien; Formosa, Fabien

2015-01-01

We developed MEMS bi-stable spring for vibration energy harvester (VEH), which consists of intrinsically curved shape spring and gravitational acceleration. By applying the gravitational acceleration, the curved beam is offset to the gravity direction. It will make more symmetrical bi-stable motion and the symmetry is improved from 3.3 to 65.4%. We proposed that the combination between curved beam and gravity acceleration for decreasing snap- through acceleration. From the analytical result, we investigate the combination can effective to use for decreasing of snap-through force. We also fabricated the prototype device by using MEMS fabrication process. The frequency response for horizontal direction and the acceleration response for vertical direction are measured. The acceleration response shows that the gravitational acceleration improves the symmetry of snap-through force. (paper)

Proposed patient motion monitoring system using feature point tracking with a web camera.

Science.gov (United States)

Miura, Hideharu; Ozawa, Shuichi; Matsuura, Takaaki; Yamada, Kiyoshi; Nagata, Yasushi

2017-12-01

Patient motion monitoring systems play an important role in providing accurate treatment dose delivery. We propose a system that utilizes a web camera (frame rate up to 30 fps, maximum resolution of 640 × 480 pixels) and an in-house image processing software (developed using Microsoft Visual C++ and OpenCV). This system is simple to use and convenient to set up. The pyramidal Lucas-Kanade method was applied to calculate motions for each feature point by analysing two consecutive frames. The image processing software employs a color scheme where the defined feature points are blue under stable (no movement) conditions and turn red along with a warning message and an audio signal (beeping alarm) for large patient movements. The initial position of the marker was used by the program to determine the marker positions in all the frames. The software generates a text file that contains the calculated motion for each frame and saves it as a compressed audio video interleave (AVI) file. We proposed a patient motion monitoring system using a web camera, which is simple and convenient to set up, to increase the safety of treatment delivery.

Hopping system control with an approximated dynamics model and upper-body motion

Energy Technology Data Exchange (ETDEWEB)

Lee, Hyang Jun; Oh, Jun Ho [KAIST, Daejeon (Korea, Republic of)

2015-11-15

A hopping system is highly non-linear due to the nature of its dynamics, which has alternating phases in a cycle, flight and stance phases and related transitions. Every control method that stabilizes the hopping system satisfies the Poincaré stability condition. At the Poincaré section, a hopping system cycle is considered as discrete sectional data set. By controlling the sectional data in a discrete control form, we can generate a stable hopping cycle. We utilize phase-mapping matrices to build a Poincaré return map by approximating the dynamics of the hopping system with SLIP model. We can generate various Poincaré stable gait patterns with the approximated discrete control form which uses upper-body motions as inputs.

Characterization of turbulence stability through the identification of multifractional Brownian motions

Science.gov (United States)

Lee, K. C.

2013-02-01

Multifractional Brownian motions have become popular as flexible models in describing real-life signals of high-frequency features in geoscience, microeconomics, and turbulence, to name a few. The time-changing Hurst exponent, which describes regularity levels depending on time measurements, and variance, which relates to an energy level, are two parameters that characterize multifractional Brownian motions. This research suggests a combined method of estimating the time-changing Hurst exponent and variance using the local variation of sampled paths of signals. The method consists of two phases: initially estimating global variance and then accurately estimating the time-changing Hurst exponent. A simulation study shows its performance in estimation of the parameters. The proposed method is applied to characterization of atmospheric stability in which descriptive statistics from the estimated time-changing Hurst exponent and variance classify stable atmosphere flows from unstable ones.

Characterization of turbulence stability through the identification of multifractional Brownian motions

Directory of Open Access Journals (Sweden)

K. C. Lee

2013-02-01

Full Text Available Multifractional Brownian motions have become popular as flexible models in describing real-life signals of high-frequency features in geoscience, microeconomics, and turbulence, to name a few. The time-changing Hurst exponent, which describes regularity levels depending on time measurements, and variance, which relates to an energy level, are two parameters that characterize multifractional Brownian motions. This research suggests a combined method of estimating the time-changing Hurst exponent and variance using the local variation of sampled paths of signals. The method consists of two phases: initially estimating global variance and then accurately estimating the time-changing Hurst exponent. A simulation study shows its performance in estimation of the parameters. The proposed method is applied to characterization of atmospheric stability in which descriptive statistics from the estimated time-changing Hurst exponent and variance classify stable atmosphere flows from unstable ones.

A synchronous surround increases the motion strength gain of motion.

Science.gov (United States)

Linares, Daniel; Nishida, Shin'ya

2013-11-12

Coherent motion detection is greatly enhanced by the synchronous presentation of a static surround (Linares, Motoyoshi, & Nishida, 2012). To further understand this contextual enhancement, here we measured the sensitivity to discriminate motion strength for several pedestal strengths with and without a surround. We found that the surround improved discrimination of low and medium motion strengths, but did not improve or even impaired discrimination of high motion strengths. We used motion strength discriminability to estimate the perceptual response function assuming additive noise and found that the surround increased the motion strength gain, rather than the response gain. Given that eye and body movements continuously introduce transients in the retinal image, it is possible that this strength gain occurs in natural vision.

Direct Contribution of Auditory Motion Information to Sound-Induced Visual Motion Perception

Directory of Open Access Journals (Sweden)

Souta Hidaka

2011-10-01

Full Text Available We have recently demonstrated that alternating left-right sound sources induce motion perception to static visual stimuli along the horizontal plane (SIVM: sound-induced visual motion perception, Hidaka et al., 2009. The aim of the current study was to elucidate whether auditory motion signals, rather than auditory positional signals, can directly contribute to the SIVM. We presented static visual flashes at retinal locations outside the fovea together with a lateral auditory motion provided by a virtual stereo noise source smoothly shifting in the horizontal plane. The flashes appeared to move in the situation where auditory positional information would have little influence on the perceived position of visual stimuli; the spatiotemporal position of the flashes was in the middle of the auditory motion trajectory. Furthermore, the auditory motion altered visual motion perception in a global motion display; in this display, different localized motion signals of multiple visual stimuli were combined to produce a coherent visual motion perception so that there was no clear one-to-one correspondence between the auditory stimuli and each visual stimulus. These findings suggest the existence of direct interactions between the auditory and visual modalities in motion processing and motion perception.

Early Site Permit Demonstration Program: Guidelines for determining design basis ground motions

International Nuclear Information System (INIS)

1993-01-01

This report develops and applies a methodology for estimating strong earthquake ground motion. The motivation was to develop a much needed tool for use in developing the seismic requirements for structural designs. An earthquake's ground motion is a function of the earthquake's magnitude, and the physical properties of the earth through which the seismic waves travel from the earthquake fault to the site of interest. The emphasis of this study is on ground motion estimation in Eastern North America (east of the Rocky Mountains), with particular emphasis on the Eastern United States and southeastern Canada. Eastern North America is a stable continental region, having sparse earthquake activity with rare occurrences of large earthquakes. While large earthquakes are of interest for assessing seismic hazard, little data exists from the region to empirically quantify their effects. Therefore, empirically based approaches that are used for other regions, such as Western North America, are not appropriate for Eastern North America. Moreover, recent advances in science and technology have now made it possible to combine theoretical and empirical methods to develop new procedures and models for estimating ground motion. The focus of the report is on the attributes of ground motion in Eastern North America that are of interest for the design of facilities such as nuclear power plants. Specifically considered are magnitudes M from 5 to 8, distances from 0 to 500 km, and frequencies from 1 to 35 Hz

Looking for chemical reaction networks exhibiting a drift along a manifold of marginally stable states.

Science.gov (United States)

Brogioli, Doriano

2013-02-07

I recently reported some examples of mass-action equations that have a continuous manifold of marginally stable stationary states [Brogioli, D., 2010. Marginally stable chemical systems as precursors of life. Phys. Rev. Lett. 105, 058102; Brogioli, D., 2011. Marginal stability in chemical systems and its relevance in the origin of life. Phys. Rev. E 84, 031931]. The corresponding chemical reaction networks show nonclassical effects, i.e. a violation of the mass-action equations, under the effect of the concentration fluctuations: the chemical system drifts along the marginally stable states. I proposed that this effect is potentially involved in abiogenesis. In the present paper, I analyze the mathematical properties of mass-action equations of marginally stable chemical reaction networks. The marginal stability implies that the mass-action equations obey some conservation law; I show that the mathematical properties of the conserved quantity characterize the motion along the marginally stable stationary state manifold, i.e. they allow to predict if the fluctuations give rise to a random walk or a drift under the effect of concentration fluctuations. Moreover, I show that the presence of the drift along the manifold of marginally stable stationary-states is a critical property, i.e. at least one of the reaction constants must be fine tuned in order to obtain the drift. Copyright © 2012 Elsevier Ltd. All rights reserved.

A multistage motion vector processing method for motion-compensated frame interpolation.

Science.gov (United States)

Huang, Ai- Mei; Nguyen, Truong Q

2008-05-01

In this paper, a novel, low-complexity motion vector processing algorithm at the decoder is proposed for motion-compensated frame interpolation or frame rate up-conversion. We address the problems of having broken edges and deformed structures in an interpolated frame by hierarchically refining motion vectors on different block sizes. Our method explicitly considers the reliability of each received motion vector and has the capability of preserving the structure information. This is achieved by analyzing the distribution of residual energies and effectively merging blocks that have unreliable motion vectors. The motion vector reliability information is also used as a prior knowledge in motion vector refinement using a constrained vector median filter to avoid choosing identical unreliable one. We also propose using chrominance information in our method. Experimental results show that the proposed scheme has better visual quality and is also robust, even in video sequences with complex scenes and fast motion.

Motion in radiotherapy

DEFF Research Database (Denmark)

Korreman, Stine Sofia

2012-01-01

This review considers the management of motion in photon radiation therapy. An overview is given of magnitudes and variability of motion of various structures and organs, and how the motion affects images by producing artifacts and blurring. Imaging of motion is described, including 4DCT and 4DPE...

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

Stability of Phase Relationships While Coordinating Arm Reaches with Whole Body Motion.

Directory of Open Access Journals (Sweden)

Romy S Bakker

Full Text Available The human movement repertoire is characterized by the smooth coordination of several body parts, including arm movements and whole body motion. The neural control of this coordination is quite complex because the various body parts have their own kinematic and dynamic properties. Behavioral inferences about the neural solution to the coordination problem could be obtained by examining the emerging phase relationship and its stability. Here, we studied the phase relationships that characterize the coordination of arm-reaching movements with passively-induced whole-body motion. Participants were laterally translated using a vestibular chair that oscillated at a fixed frequency of 0.83 Hz. They were instructed to reach between two targets that were aligned either parallel or orthogonal to the whole body motion. During the first cycles of body motion, a metronome entrained either an in-phase or an anti-phase relationship between hand and body motion, which was released at later cycles to test phase stability. Results suggest that inertial forces play an important role when coordinating reaches with cyclic whole-body motion. For parallel reaches, we found a stable in-phase and an unstable anti-phase relationship. When the latter was imposed, it readily transitioned or drifted back toward an in-phase relationship at cycles without metronomic entrainment. For orthogonal reaches, we did not find a clear difference in stability between in-phase and anti-phase relationships. Computer simulations further show that cost models that minimize energy expenditure (i.e. net torques or endpoint variance of the reach cannot fully explain the observed coordination patterns. We discuss how predictive control and impedance control processes could be considered important mechanisms underlying the rhythmic coordination of arm reaches and body motion.

Smoothing Motion Estimates for Radar Motion Compensation.

Energy Technology Data Exchange (ETDEWEB)

Doerry, Armin W. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

2017-07-01

Simple motion models for complex motion environments are often not adequate for keeping radar data coherent. Eve n perfect motion samples appli ed to imperfect models may lead to interim calculations e xhibiting errors that lead to degraded processing results. Herein we discuss a specific i ssue involving calculating motion for groups of pulses, with measurements only available at pulse-group boundaries. - 4 - Acknowledgements This report was funded by General A tomics Aeronautical Systems, Inc. (GA-ASI) Mission Systems under Cooperative Re search and Development Agre ement (CRADA) SC08/01749 between Sandia National Laboratories and GA-ASI. General Atomics Aeronautical Systems, Inc. (GA-ASI), an affilia te of privately-held General Atomics, is a leading manufacturer of Remotely Piloted Aircraft (RPA) systems, radars, and electro-optic and rel ated mission systems, includin g the Predator(r)/Gray Eagle(r)-series and Lynx(r) Multi-mode Radar.

Directional Limits on Motion Transparency Assessed Through Colour-Motion Binding.

Science.gov (United States)

Maloney, Ryan T; Clifford, Colin W G; Mareschal, Isabelle

2018-03-01

Motion-defined transparency is the perception of two or more distinct moving surfaces at the same retinal location. We explored the limits of motion transparency using superimposed surfaces of randomly positioned dots defined by differences in motion direction and colour. In one experiment, dots were red or green and we varied the proportion of dots of a single colour that moved in a single direction ('colour-motion coherence') and measured the threshold direction difference for discriminating between two directions. When colour-motion coherences were high (e.g., 90% of red dots moving in one direction), a smaller direction difference was required to correctly bind colour with direction than at low coherences. In another experiment, we varied the direction difference between the surfaces and measured the threshold colour-motion coherence required to discriminate between them. Generally, colour-motion coherence thresholds decreased with increasing direction differences, stabilising at direction differences around 45°. Different stimulus durations were compared, and thresholds were higher at the shortest (150 ms) compared with the longest (1,000 ms) duration. These results highlight different yet interrelated aspects of the task and the fundamental limits of the mechanisms involved: the resolution of narrowly separated directions in motion processing and the local sampling of dot colours from each surface.

MotionExplorer: exploratory search in human motion capture data based on hierarchical aggregation.

Science.gov (United States)

Bernard, Jürgen; Wilhelm, Nils; Krüger, Björn; May, Thorsten; Schreck, Tobias; Kohlhammer, Jörn

2013-12-01

We present MotionExplorer, an exploratory search and analysis system for sequences of human motion in large motion capture data collections. This special type of multivariate time series data is relevant in many research fields including medicine, sports and animation. Key tasks in working with motion data include analysis of motion states and transitions, and synthesis of motion vectors by interpolation and combination. In the practice of research and application of human motion data, challenges exist in providing visual summaries and drill-down functionality for handling large motion data collections. We find that this domain can benefit from appropriate visual retrieval and analysis support to handle these tasks in presence of large motion data. To address this need, we developed MotionExplorer together with domain experts as an exploratory search system based on interactive aggregation and visualization of motion states as a basis for data navigation, exploration, and search. Based on an overview-first type visualization, users are able to search for interesting sub-sequences of motion based on a query-by-example metaphor, and explore search results by details on demand. We developed MotionExplorer in close collaboration with the targeted users who are researchers working on human motion synthesis and analysis, including a summative field study. Additionally, we conducted a laboratory design study to substantially improve MotionExplorer towards an intuitive, usable and robust design. MotionExplorer enables the search in human motion capture data with only a few mouse clicks. The researchers unanimously confirm that the system can efficiently support their work.

A programmable motion phantom for quality assurance of motion management in radiotherapy

International Nuclear Information System (INIS)

Dunn, L.; Franich, R.D.; Kron, T.; Taylor, M.L.; Johnston, P.N.; McDermott, L.N.; Callahan, J.

2012-01-01

A commercially available motion phantom (QUASAR, Modus Medical) was modified for programmable motion control with the aim of reproducing patient respiratory motion in one dimension in both the anterior–posterior and superior–inferior directions, as well as, providing controllable breath-hold and sinusoidal patterns for the testing of radiotherapy gating systems. In order to simulate realistic patient motion, the DC motor was replaced by a stepper motor. A separate 'chest-wall' motion platform was also designed to accommodate a variety of surrogate marker systems. The platform employs a second stepper motor that allows for the decoupling of the chest-wall and insert motion. The platform's accuracy was tested by replicating patient traces recorded with the Varian real-time position management (RPM) system and comparing the motion platform's recorded motion trace with the original patient data. Six lung cancer patient traces recorded with the RPM system were uploaded to the motion platform's in-house control software and subsequently replicated through the phantom motion platform. The phantom's motion profile was recorded with the RPM system and compared to the original patient data. Sinusoidal and breath-hold patterns were simulated with the motion platform and recorded with the RPM system to verify the systems potential for routine quality assurance of commercial radiotherapy gating systems. There was good correlation between replicated and actual patient data (P 0.003). Mean differences between the location of maxima in replicated and patient data-sets for six patients amounted to 0.034 cm with the corresponding minima mean equal to 0.010 cm. The upgraded motion phantom was found to replicate patient motion accurately as well as provide useful test patterns to aid in the quality assurance of motion management methods and technologies.

Integrated fMRI Preprocessing Framework Using Extended Kalman Filter for Estimation of Slice-Wise Motion

Directory of Open Access Journals (Sweden)

Basile Pinsard

2018-04-01

Full Text Available Functional MRI acquisition is sensitive to subjects' motion that cannot be fully constrained. Therefore, signal corrections have to be applied a posteriori in order to mitigate the complex interactions between changing tissue localization and magnetic fields, gradients and readouts. To circumvent current preprocessing strategies limitations, we developed an integrated method that correct motion and spatial low-frequency intensity fluctuations at the level of each slice in order to better fit the acquisition processes. The registration of single or multiple simultaneously acquired slices is achieved online by an Iterated Extended Kalman Filter, favoring the robust estimation of continuous motion, while an intensity bias field is non-parametrically fitted. The proposed extraction of gray-matter BOLD activity from the acquisition space to an anatomical group template space, taking into account distortions, better preserves fine-scale patterns of activity. Importantly, the proposed unified framework generalizes to high-resolution multi-slice techniques. When tested on simulated and real data the latter shows a reduction of motion explained variance and signal variability when compared to the conventional preprocessing approach. These improvements provide more stable patterns of activity, facilitating investigation of cerebral information representation in healthy and/or clinical populations where motion is known to impact fine-scale data.

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...

Evaluation of control rod motion simulator research reactors

International Nuclear Information System (INIS)

Sanda

2010-01-01

Motion simulator has been carried out testing of the reactor control rod using a servomotor. Reactor control rod motion at any point should be in the right position, one of the motors that can move in a precise and correct the servo motor. To ensure that the servo motor to move in accordance with the desired program, then the servomotor function test for motor work to ensure the performance of the appliance. Tests carried out on meshes stress disorder, the load is stable within a certain period and travel time safety control rod up and down, travel time regulating control rods up and down and travel time compensation control rods up and down. In testing the breakdown voltage Vout nets at 24 V, 6.5 A with 12 Ω load deviation obtained V0 = V1 = 0.1% and 0.65% and for the stability of the load in a certain time deviation V = 0.7125%, next to the breakdown voltage Vout nets at 12V, 4.2 A with a 6 Ω load deviation obtained V0 = V1 = 0.275% and 1.158% for the stability of the load in a certain time deviation V = 1.463% and the net-voltage noise nets on Vout 24 V, 4.5 A with 12 Ω load deviation obtained V0 = V1 = 0.196% and 0.496% and for the stability of the load in a certain time deviation V = 0.3625%. While the travel time of a safety control rod up and down, up and down the regulator and compensation rise and fall showed a steady linear graph. The results show that the performance of the servo motor is very stable with the working area below the tolerance limit, it is 5% - 10%. (author)

Applied research of embedded WiFi technology in the motion capture system

Science.gov (United States)

Gui, Haixia

2012-04-01

Embedded wireless WiFi technology is one of the current wireless hot spots in network applications. This paper firstly introduces the definition and characteristics of WiFi. With the advantages of WiFi such as using no wiring, simple operation and stable transmission, this paper then gives a system design for the application of embedded wireless WiFi technology in the motion capture system. Also, it verifies the effectiveness of design in the WiFi-based wireless sensor hardware and software program.

Embodied memory: effective and stable perception by combining optic flow and image structure.

Science.gov (United States)

Pan, Jing Samantha; Bingham, Ned; Bingham, Geoffrey P

2013-12-01

Visual perception studies typically focus either on optic flow structure or image structure, but not on the combination and interaction of these two sources of information. Each offers unique strengths in contrast to the other's weaknesses. Optic flow yields intrinsically powerful information about 3D structure, but is ephemeral. It ceases when motion stops. Image structure is less powerful in specifying 3D structure, but is stable. It remains when motion stops. Optic flow and image structure are intrinsically related in vision because the optic flow carries one image to the next. This relation is especially important in the context of progressive occlusion, in which optic flow provides information about the location of targets hidden in subsequent image structure. In four experiments, we investigated the role of image structure in "embodied memory" in contrast to memory that is only in the head. We found that either optic flow (Experiment 1) or image structure (Experiment 2) alone were relatively ineffective, whereas the combination was effective and, in contrast to conditions requiring reliance on memory-in-the-head, much more stable over extended time (Experiments 2 through 4). Limits well documented for visual short memory (that is, memory-in-the-head) were strongly exceeded by embodied memory. The findings support J. J. Gibson's (1979/1986, The Ecological Approach to Visual Perception, Boston, MA, Houghton Mifflin) insights about progressive occlusion and the embodied nature of perception and memory.

Experimental investigation of single small bubble motion in linear shear flow in water

International Nuclear Information System (INIS)

Li, Zhongchun; Zhao, Yang; Song, Xiaoming; Yu, Hongxing; Jiang, Shengyao; Ishii, Mamoru

2016-01-01

Highlights: • The bubble motion in simple linear shear flow was experimentally investigated. • The bubble trajectories, bubble velocity and drag and lift force were obtained using image process routine. • The bubble trajectory was coupled with a zigzag motion and incline path. • The lift force was kept negative and it decreased when bubble diameter and shear flow magnitude increased. - Abstract: The motion of small bubble in a simple shear flow in water was experimental studied. Stable shear flow with low turbulence level was achieved with curved screen and measured using LDV. The bubbles were captured by high speed camera and the captured images were processed with digital image routine. The bubble was released from a capillary tube. The instantaneous bubble position, bubble velocity and forces were obtained based on the captured parameters. The quasi-steady lift coefficient was determined by the linear fitting of the bubble trajectory of several cycles. The results indicated that the lateral migration was coupled with the zigzag motion of bubble in the present experiment. The bubble migrated to the left side and its quasi-steady lift coefficient was negative. Good repeatable results were observed by measurements of 18 bubbles. The bubble motion in shear flow in water was first experimental studied and negative lift force was observed in the present study condition. The lift coefficient decreased when shear stress magnitude or bubble diameter increased in the present experiment condition.

Proper motion survey for solar nearby stars

International Nuclear Information System (INIS)

Goldman, Bertrand

2001-01-01

For its microlensing observations EROS 2 built one of the largest CCD mosaic opera ting since 1996. This instrument allowed us to survey a large area of the sky, to look for faint, cool compact objects in the Solar neighborhood that may contribute to the Dark Matter revealed by flat rotation curves of spiral galaxies and the Milky Way. We imaged over 400 square degrees, at least three times over four years, with a single, stable instrument. The aim of this work is the reduction, the analysis and the detection of high proper motion objects that would look like those expected in a dark halo. We selected and analyzed thousands of images taken in two bands, visible and near-infrared, and obtained a catalogue of several thousand stars with proper motion typically higher than 80 milli-arc-seconds per year. None of these candidates displays the expected properties of the halo objects: very high proper motion and faintness. The second part of our work was to put constraints on the contributions of white dwarfs and brown dwarfs ta the halo. To do that, we simulated our data set and estimated our sensitivity to halo objects. We compared our results about moderately high proper motion stars with existing Galactic models, and confirmed the robustness of these models. We deduced a upper limit ta the contribution of M_v = 17.5 white dwarfs to the standard halo of 10% (at the 95% confidence level), or 5% of a 14 Gyr old halo, and to the contribution of brown dwarfs of 7% (95% C.L.). Finally, among our candidates, several interesting objects, that do not belong to the halo but are among the coolest and faintest known, have been discovered. Systematic search for faint, nearby objects thus lead us to study disk L dwarfs, as well as old white dwarfs of the disk. (author) [fr

Early Site Permit Demonstration Program: Guidelines for determining design basis ground motions

International Nuclear Information System (INIS)

1993-01-01

This report develops and applies a methodology for estimating strong earthquake ground motion. The motivation was to develop a much needed tool for use in developing the seismic requirements for structural designs. An earthquake's ground motion is a function of the earthquake's magnitude, and the physical properties of the earth through which the seismic waves travel from the earthquake fault to the site of interest. The emphasis of this study is on ground motion estimation in Eastern North America (east of the Rocky Mountains), with particular emphasis on the Eastern United States and southeastern Canada. Eastern North America is a stable continental region, having sparse earthquake activity with rare occurrences of large earthquakes. While large earthquakes are of interest for assessing seismic hazard, little data exists from the region to empirically quantify their effects. Therefore, empirically based approaches that are used for other regions, such as Western North America, are not appropriate for Eastern North America. Moreover, recent advances in science and technology have now made it possible to combine theoretical and empirical methods to develop new procedures and models for estimating ground motion. The focus of the report is on the attributes of ground motion in Eastern North America that are of interest for the design of facilities such as nuclear power plants. Specifically considered are magnitudes M from 5 to 8, distances from 0 to 500 km, and frequencies from 1 to 35 Hz. This document, Volume IV, provides Appendix 8.B, Laboratory Investigations of Dynamic Properties of Reference Sites

Early Site Permit Demonstration Program: Guidelines for determining design basis ground motions. Volume 2, Appendices

Energy Technology Data Exchange (ETDEWEB)

1993-03-18

This report develops and applies a methodology for estimating strong earthquake ground motion. The motivation was to develop a much needed tool for use in developing the seismic requirements for structural designs. An earthquake`s ground motion is a function of the earthquake`s magnitude, and the physical properties of the earth through which the seismic waves travel from the earthquake fault to the site of interest. The emphasis of this study is on ground motion estimation in Eastern North America (east of the Rocky Mountains), with particular emphasis on the Eastern United States and southeastern Canada. Eastern North America is a stable continental region, having sparse earthquake activity with rare occurrences of large earthquakes. While large earthquakes are of interest for assessing seismic hazard, little data exists from the region to empirically quantify their effects. The focus of the report is on the attributes of ground motion in Eastern North America that are of interest for the design of facilities such as nuclear power plants. This document, Volume II, contains Appendices 2, 3, 5, 6, and 7 covering the following topics: Eastern North American Empirical Ground Motion Data; Examination of Variance of Seismographic Network Data; Soil Amplification and Vertical-to-Horizontal Ratios from Analysis of Strong Motion Data From Active Tectonic Regions; Revision and Calibration of Ou and Herrmann Method; Generalized Ray Procedure for Modeling Ground Motion Attenuation; Crustal Models for Velocity Regionalization; Depth Distribution Models; Development of Generic Site Effects Model; Validation and Comparison of One-Dimensional Site Response Methodologies; Plots of Amplification Factors; Assessment of Coupling Between Vertical & Horizontal Motions in Nonlinear Site Response Analysis; and Modeling of Dynamic Soil Properties.

Multi-parameter actuation of a neutrally stable shell: a flexible gear-less motor.

Science.gov (United States)

Hamouche, W; Maurini, C; Vidoli, S; Vincenti, A

2017-08-01

We have designed and tested experimentally a morphing structure consisting of a neutrally stable thin cylindrical shell driven by a multi-parameter piezoelectric actuation. The shell is obtained by plastically deforming an initially flat copper disc, so as to induce large isotropic and almost uniform inelastic curvatures. Following the plastic deformation, in a perfectly isotropic system, the shell is theoretically neutrally stable, having a continuous set of stable cylindrical shapes corresponding to the rotation of the axis of maximal curvature. Small imperfections render the actual structure bistable, giving preferred orientations. A three-parameter piezoelectric actuation, exerted through micro-fibre-composite actuators, allows us to add a small perturbation to the plastic inelastic curvature and to control the direction of maximal curvature. This actuation law is designed through a geometrical analogy based on a fully nonlinear inextensible uniform-curvature shell model. We report on the fabrication, identification and experimental testing of a prototype and demonstrate the effectiveness of the piezoelectric actuators in controlling its shape. The resulting motion is an apparent rotation of the shell, controlled by the voltages as in a 'gear-less motor', which is, in reality, a precession of the axis of principal curvature.

Is Diaphragm Motion a Good Surrogate for Liver Tumor Motion?

Energy Technology Data Exchange (ETDEWEB)

Yang, Juan [Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina (United States); School of Information Science and Engineering, Shandong University, Jinan, Shandong (China); Cai, Jing [Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina (United States); Wang, Hongjun [School of Information Science and Engineering, Shandong University, Jinan, Shandong (China); Chang, Zheng; Czito, Brian G. [Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina (United States); Bashir, Mustafa R. [Department of Radiology, Duke University Medical Center, Durham, North Carolina (United States); Palta, Manisha [Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina (United States); Yin, Fang-Fang, E-mail: fangfang.yin@duke.edu [Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina (United States)

2014-11-15

Purpose: To evaluate the relationship between liver tumor motion and diaphragm motion. Methods and Materials: Fourteen patients with hepatocellular carcinoma (10 of 14) or liver metastases (4 of 14) undergoing radiation therapy were included in this study. All patients underwent single-slice cine–magnetic resonance imaging simulations across the center of the tumor in 3 orthogonal planes. Tumor and diaphragm motion trajectories in the superior–inferior (SI), anterior–posterior (AP), and medial–lateral (ML) directions were obtained using an in-house-developed normalized cross-correlation–based tracking technique. Agreement between the tumor and diaphragm motion was assessed by calculating phase difference percentage, intraclass correlation coefficient, and Bland-Altman analysis (Diff). The distance between the tumor and tracked diaphragm area was analyzed to understand its impact on the correlation between the 2 motions. Results: Of all patients, the mean (±standard deviation) phase difference percentage values were 7.1% ± 1.1%, 4.5% ± 0.5%, and 17.5% ± 4.5% in the SI, AP, and ML directions, respectively. The mean intraclass correlation coefficient values were 0.98 ± 0.02, 0.97 ± 0.02, and 0.08 ± 0.06 in the SI, AP, and ML directions, respectively. The mean Diff values were 2.8 ± 1.4 mm, 2.4 ± 1.1 mm, and 2.2 ± 0.5 mm in the SI, AP, and ML directions, respectively. Tumor and diaphragm motions had high concordance when the distance between the tumor and tracked diaphragm area was small. Conclusions: This study showed that liver tumor motion had good correlation with diaphragm motion in the SI and AP directions, indicating diaphragm motion in the SI and AP directions could potentially be used as a reliable surrogate for liver tumor motion.

Can walking motions improve visually induced rotational self-motion illusions in virtual reality?

Science.gov (United States)

Riecke, Bernhard E; Freiberg, Jacob B; Grechkin, Timofey Y

2015-02-04

Illusions of self-motion (vection) can provide compelling sensations of moving through virtual environments without the need for complex motion simulators or large tracked physical walking spaces. Here we explore the interaction between biomechanical cues (stepping along a rotating circular treadmill) and visual cues (viewing simulated self-rotation) for providing stationary users a compelling sensation of rotational self-motion (circular vection). When tested individually, biomechanical and visual cues were similarly effective in eliciting self-motion illusions. However, in combination they yielded significantly more intense self-motion illusions. These findings provide the first compelling evidence that walking motions can be used to significantly enhance visually induced rotational self-motion perception in virtual environments (and vice versa) without having to provide for physical self-motion or motion platforms. This is noteworthy, as linear treadmills have been found to actually impair visually induced translational self-motion perception (Ash, Palmisano, Apthorp, & Allison, 2013). Given the predominant focus on linear walking interfaces for virtual-reality locomotion, our findings suggest that investigating circular and curvilinear walking interfaces offers a promising direction for future research and development and can help to enhance self-motion illusions, presence and immersion in virtual-reality systems. © 2015 ARVO.

Stable isotopes

International Nuclear Information System (INIS)

Evans, D.K.

1986-01-01

Seventy-five percent of the world's stable isotope supply comes from one producer, Oak Ridge Nuclear Laboratory (ORNL) in the US. Canadian concern is that foreign needs will be met only after domestic needs, thus creating a shortage of stable isotopes in Canada. This article describes the present situation in Canada (availability and cost) of stable isotopes, the isotope enrichment techniques, and related research programs at Chalk River Nuclear Laboratories (CRNL)

Curves from Motion, Motion from Curves

Science.gov (United States)

2000-01-01

De linearum curvarum cum lineis rectis comparatione dissertatio geometrica - an appendix to a treatise by de Lalouv~re (this was the only publication... correct solution to the problem of motion in the gravity of a permeable rotating Earth, considered by Torricelli (see §3). If the Earth is a homogeneous...in 1686, which contains the correct solution as part of a remarkably comprehensive theory of orbital motions under centripetal forces. It is a

POSTURAL CONTROL IN HEALTHY YOUNG ADULTS WITH AND WITHOUT CHRONIC MOTION SENSITIVITY

Directory of Open Access Journals (Sweden)

Alyahya D

2016-02-01

Full Text Available Background: Postural control requires complex processing of peripheral sensory inputs from the visual, somatosensory and vestibular systems. Motion sensitivity and decreased postural control are influenced by visual-vestibular conflicts.The purpose of this study was to measure the difference between the postural control of healthy adults with and without history of sub-clinical chronic motion sensitivity using a computerized dynamic posturography in a virtual reality environment. Sub-clinical chronic motion sensitivity was operationally defined as a history of avoiding activities causing dizziness, nausea, imbalance, and/or blurred vision without having a related medical diagnosis. Methods: Twenty healthy adults between 22 and 33 years of age participated in the study. Eleven subjects had sub-clinical chronic motion sensitivity and 9 subjects did not. Postural control was measured in both groups using the Bertec Balance Advantage-Dynamic Computerized Dynamic Posturography with Immersion Virtual Reality (CDP-IVR. The CDP-IVR reports an over-all equilibrium score based on subjects’ center of gravity displacement and postural sway while immersed in a virtual reality environment. Subjects were tested on stable (condition 1 and unstable (condition2 platform conditions. Results: There was no significant difference between the two groups in terms of mean age, height, weight, body mass index in kg/m2, postural control scores for conditions 2, and average (p>0.05. However, significant differences were observed in mean postural control for condition 1 between groups (p=0.03. Conclusions: Results of this study suggest that healthy young adults without chronic sub-clinical motion sensitivity have better postural control than those with chronic sub-clinical motion sensitivity. Further investigation is warranted to explore wider age ranges with larger samples sizes as well as intervention strategies to improve postural control.

Visual motion influences the contingent auditory motion aftereffect

NARCIS (Netherlands)

Vroomen, J.; de Gelder, B.

2003-01-01

In this study, we show that the contingent auditory motion aftereffect is strongly influenced by visual motion information. During an induction phase, participants listened to rightward-moving sounds with falling pitch alternated with leftward-moving sounds with rising pitch (or vice versa).

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.

Attention and apparent motion.

Science.gov (United States)

Horowitz, T; Treisman, A

1994-01-01

Two dissociations between short- and long-range motion in visual search are reported. Previous research has shown parallel processing for short-range motion and apparently serial processing for long-range motion. This finding has been replicated and it has also been found that search for short-range targets can be impaired both by using bicontrast stimuli, and by prior adaptation to the target direction of motion. Neither factor impaired search in long-range motion displays. Adaptation actually facilitated search with long-range displays, which is attributed to response-level effects. A feature-integration account of apparent motion is proposed. In this theory, short-range motion depends on specialized motion feature detectors operating in parallel across the display, but subject to selective adaptation, whereas attention is needed to link successive elements when they appear at greater separations, or across opposite contrasts.

Example-based human motion denoising.

Science.gov (United States)

Lou, Hui; Chai, Jinxiang

2010-01-01

With the proliferation of motion capture data, interest in removing noise and outliers from motion capture data has increased. In this paper, we introduce an efficient human motion denoising technique for the simultaneous removal of noise and outliers from input human motion data. The key idea of our approach is to learn a series of filter bases from precaptured motion data and use them along with robust statistics techniques to filter noisy motion data. Mathematically, we formulate the motion denoising process in a nonlinear optimization framework. The objective function measures the distance between the noisy input and the filtered motion in addition to how well the filtered motion preserves spatial-temporal patterns embedded in captured human motion data. Optimizing the objective function produces an optimal filtered motion that keeps spatial-temporal patterns in captured motion data. We also extend the algorithm to fill in the missing values in input motion data. We demonstrate the effectiveness of our system by experimenting with both real and simulated motion data. We also show the superior performance of our algorithm by comparing it with three baseline algorithms and to those in state-of-art motion capture data processing software such as Vicon Blade.

Cooling the center-of-mass motion of a diamond nanocrystal in a magneto-gravitational trap

Science.gov (United States)

Hsu, Jen-Feng

A magneto-gravitational trap for micro/nanometer sized diamagnetic particles, such as diamond nanocrystals, is tested and characterized. After exploring various other systems, such as a suspended graphene beam and an optical trap, this magneto-gravitational nanomechanical trapping system for diamond with nitrogen-vacancy (NV) centers presents unique advantages for experiments in fundamental quantum mechanics. Those include, for example, the generation of large quantum superposition states and tests of quantum gravity. Features are demonstrated for this system, such as stable and passive levitation from atmospheric pressure to high vacuum, low resonant frequencies and damping rates, and cooling of the center-of-mass motions to below 1 K. The construction of the trap, vacuum system, optics, and motion detection electronics are described in detail.

A Motion-Adaptive Deinterlacer via Hybrid Motion Detection and Edge-Pattern Recognition

Directory of Open Access Journals (Sweden)

He-Yuan Lin

2008-03-01

Full Text Available A novel motion-adaptive deinterlacing algorithm with edge-pattern recognition and hybrid motion detection is introduced. The great variety of video contents makes the processing of assorted motion, edges, textures, and the combination of them very difficult with a single algorithm. The edge-pattern recognition algorithm introduced in this paper exhibits the flexibility in processing both textures and edges which need to be separately accomplished by line average and edge-based line average before. Moreover, predicting the neighboring pixels for pattern analysis and interpolation further enhances the adaptability of the edge-pattern recognition unit when motion detection is incorporated. Our hybrid motion detection features accurate detection of fast and slow motion in interlaced video and also the motion with edges. Using only three fields for detection also renders higher temporal correlation for interpolation. The better performance of our deinterlacing algorithm with higher content-adaptability and less memory cost than the state-of-the-art 4-field motion detection algorithms can be seen from the subjective and objective experimental results of the CIF and PAL video sequences.

A Motion-Adaptive Deinterlacer via Hybrid Motion Detection and Edge-Pattern Recognition

Directory of Open Access Journals (Sweden)

Li Hsin-Te

2008-01-01

Full Text Available Abstract A novel motion-adaptive deinterlacing algorithm with edge-pattern recognition and hybrid motion detection is introduced. The great variety of video contents makes the processing of assorted motion, edges, textures, and the combination of them very difficult with a single algorithm. The edge-pattern recognition algorithm introduced in this paper exhibits the flexibility in processing both textures and edges which need to be separately accomplished by line average and edge-based line average before. Moreover, predicting the neighboring pixels for pattern analysis and interpolation further enhances the adaptability of the edge-pattern recognition unit when motion detection is incorporated. Our hybrid motion detection features accurate detection of fast and slow motion in interlaced video and also the motion with edges. Using only three fields for detection also renders higher temporal correlation for interpolation. The better performance of our deinterlacing algorithm with higher content-adaptability and less memory cost than the state-of-the-art 4-field motion detection algorithms can be seen from the subjective and objective experimental results of the CIF and PAL video sequences.

Stable Isotope Data

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Tissue samples (skin, bone, blood, muscle) are analyzed for stable carbon, stable nitrogen, and stable sulfur analysis. Many samples are used in their entirety for...

stableGP

Data.gov (United States)

National Aeronautics and Space Administration — The code in the stableGP package implements Gaussian process calculations using efficient and numerically stable algorithms. Description of the algorithms is in the...

Alpha motion based on a motion detector, but not on the Müller-Lyer illusion

Science.gov (United States)

Suzuki, Masahiro

2014-07-01

This study examined the mechanism of alpha motion, the apparent motion of the Müller-Lyer figure's shaft that occurs when the arrowheads and arrow tails are alternately presented. The following facts were found: (a) reduced exposure duration decreased the amount of alpha motion, and this phenomenon was not explainable by the amount of the Müller-Lyer illusion; (b) the motion aftereffect occurred after adaptation to alpha motion; (c) occurrence of alpha motion became difficult when the temporal frequency increased, and this characteristic of alpha motion was similar to the characteristic of a motion detector that motion detection became difficult when the temporal frequency increased from the optimal frequency. These findings indicated that alpha motion occurs on the basis of a motion detector but not on the Müller-Lyer illusion, and that the mechanism of alpha motion is the same as that of general motion perception.

MotionFlow: Visual Abstraction and Aggregation of Sequential Patterns in Human Motion Tracking Data.

Science.gov (United States)

Jang, Sujin; Elmqvist, Niklas; Ramani, Karthik

2016-01-01

Pattern analysis of human motions, which is useful in many research areas, requires understanding and comparison of different styles of motion patterns. However, working with human motion tracking data to support such analysis poses great challenges. In this paper, we propose MotionFlow, a visual analytics system that provides an effective overview of various motion patterns based on an interactive flow visualization. This visualization formulates a motion sequence as transitions between static poses, and aggregates these sequences into a tree diagram to construct a set of motion patterns. The system also allows the users to directly reflect the context of data and their perception of pose similarities in generating representative pose states. We provide local and global controls over the partition-based clustering process. To support the users in organizing unstructured motion data into pattern groups, we designed a set of interactions that enables searching for similar motion sequences from the data, detailed exploration of data subsets, and creating and modifying the group of motion patterns. To evaluate the usability of MotionFlow, we conducted a user study with six researchers with expertise in gesture-based interaction design. They used MotionFlow to explore and organize unstructured motion tracking data. Results show that the researchers were able to easily learn how to use MotionFlow, and the system effectively supported their pattern analysis activities, including leveraging their perception and domain knowledge.

Spectral analysis of underwater explosions in the Dead Sea

Science.gov (United States)

Gitterman, Y.; Ben-Avraham, Z.; Ginzburg, A.

1998-08-01

The present study utilizes the Israel Seismic Network (ISN) as a spatially distributed multichannel system for the discrimination of low-magnitude events (ML UWEs) and 16 earthquakes in the magnitude range ML = 1.6-2.8, within distances of 10-150 km, recorded by the ISN, were selected for the analysis. The analysis is based on a smoothed (0.5 Hz window) Fourier spectrum of the whole signal (defined by the signal-to-noise criterion), without picking separate wave phases. It was found that the classical discriminant of the seismic energy ratio between the relatively low-frequency (1-6 Hz) and high-frequency (6-11 Hz) bands, averaged over an ISN subnetwork, showed an overlap between UWEs and earthquakes and cannot itself provide reliable identification. We developed and tested a new multistation discriminant based on the low- frequency spectral modulation (LFSM) method. In our case the LFSM is associated with the bubbling effect in underwater explosions. The method demonstrates a distinct azimuth-invariant coherency of spectral shapes in the low-frequency range (1-12 Hz) of short-period seismometer systems. The coherency of the modulated spectra for different ISN stations was measured by semblance statistics commonly used in seismic prospecting for phase correlation in the time domain. The modified statistics provided an almost complete separation between earthquakes and underwater explosions.

Learning Motion Features for Example-Based Finger Motion Estimation for Virtual Characters

Science.gov (United States)

Mousas, Christos; Anagnostopoulos, Christos-Nikolaos

2017-09-01

This paper presents a methodology for estimating the motion of a character's fingers based on the use of motion features provided by a virtual character's hand. In the presented methodology, firstly, the motion data is segmented into discrete phases. Then, a number of motion features are computed for each motion segment of a character's hand. The motion features are pre-processed using restricted Boltzmann machines, and by using the different variations of semantically similar finger gestures in a support vector machine learning mechanism, the optimal weights for each feature assigned to a metric are computed. The advantages of the presented methodology in comparison to previous solutions are the following: First, we automate the computation of optimal weights that are assigned to each motion feature counted in our metric. Second, the presented methodology achieves an increase (about 17%) in correctly estimated finger gestures in comparison to a previous method.

Automated fetal brain segmentation from 2D MRI slices for motion correction.

Science.gov (United States)

Keraudren, K; Kuklisova-Murgasova, M; Kyriakopoulou, V; Malamateniou, C; Rutherford, M A; Kainz, B; Hajnal, J V; Rueckert, D

2014-11-01

Motion correction is a key element for imaging the fetal brain in-utero using Magnetic Resonance Imaging (MRI). Maternal breathing can introduce motion, but a larger effect is frequently due to fetal movement within the womb. Consequently, imaging is frequently performed slice-by-slice using single shot techniques, which are then combined into volumetric images using slice-to-volume reconstruction methods (SVR). For successful SVR, a key preprocessing step is to isolate fetal brain tissues from maternal anatomy before correcting for the motion of the fetal head. This has hitherto been a manual or semi-automatic procedure. We propose an automatic method to localize and segment the brain of the fetus when the image data is acquired as stacks of 2D slices with anatomy misaligned due to fetal motion. We combine this segmentation process with a robust motion correction method, enabling the segmentation to be refined as the reconstruction proceeds. The fetal brain localization process uses Maximally Stable Extremal Regions (MSER), which are classified using a Bag-of-Words model with Scale-Invariant Feature Transform (SIFT) features. The segmentation process is a patch-based propagation of the MSER regions selected during detection, combined with a Conditional Random Field (CRF). The gestational age (GA) is used to incorporate prior knowledge about the size and volume of the fetal brain into the detection and segmentation process. The method was tested in a ten-fold cross-validation experiment on 66 datasets of healthy fetuses whose GA ranged from 22 to 39 weeks. In 85% of the tested cases, our proposed method produced a motion corrected volume of a relevant quality for clinical diagnosis, thus removing the need for manually delineating the contours of the brain before motion correction. Our method automatically generated as a side-product a segmentation of the reconstructed fetal brain with a mean Dice score of 93%, which can be used for further processing. Copyright �

SU-E-T-160: Characterization and Monitoring of Linear Accelerator Gantry Radiation Isocenter Motion

International Nuclear Information System (INIS)

Letourneau, D; Amin, N; Wang, K; Norrlinger, B; Jaffray, D; McNiven, A

2015-01-01

Purpose: To characterize the motion of the radiation isocenter, over time, as a function of gantry rotation for multiple linear accelerators (linacs). Two semi-automated image-based quality control (QC) test workflows were designed to achieve this goal. Methods: The full QC-test workflow for motion characterization consisted of acquiring 16 megavoltage images at 8 gantry angles of a ball-bearing suspended off the end of the couch. Performance constancy was assessed using a shortened QC-test workflow which consisted of imaging a cube phantom placed on the couch (5 images at 4 gantry angles). Both workflows use an image processing algorithm to determine the field center and phantom position on each image and computed radiation isocenter motion as a function of gantry angle. Motion was characterized for 9 linacs of same model and performance monitored for 2 months on 3 linacs. Results: The maximum isocenter motion determined with the full-workflow for 9 linacs was within 0.38–0.79 mm. The shortened-workflow usually agreed within 0.1 mm with the full-workflow and the time required for these methods was about 4 and 15 min, respectively. For all linacs, the isocenter motion perpendicular to the gantry rotation plane followed a consistent pattern with maximum amplitude of 0.36–0.59 mm. In the gantry rotation plane, the variation among linacs was higher and the beam axis described a circle of up to 0.6 mm radius around the gantry axis of rotation (2 linacs). The radiation isocenter motion was stable as a function of time for the monitored linacs and was within ±0.1 mm of the average. Conclusion: Radiation isocenter motion parallel and perpendicular to the gantry rotation plane was characterized. In the gantry rotation plane, beam spot positioning adjustment might be used to reduce the observed radiation isocenter motion. A shortened-workflow was designed and enables performance monitoring over time

High-resolution simulations of unstable cylindrical gravity currents undergoing wandering and splitting motions in a rotating system

Science.gov (United States)

Dai, Albert; Wu, Ching-Sen

2018-02-01

High-resolution simulations of unstable cylindrical gravity currents when wandering and splitting motions occur in a rotating system are reported. In this study, our attention is focused on the situation of unstable rotating cylindrical gravity currents when the ratio of Coriolis to inertia forces is larger, namely, 0.5 ≤ C ≤ 2.0, in comparison to the stable ones when C ≤ 0.3 as investigated previously by the authors. The simulations reproduce the major features of the unstable rotating cylindrical gravity currents observed in the laboratory, i.e., vortex-wandering or vortex-splitting following the contraction-relaxation motion, and good agreement is found when compared with the experimental results on the outrush radius of the advancing front and on the number of bulges. Furthermore, the simulations provide energy budget information which could not be attained in the laboratory. After the heavy fluid is released, the heavy fluid collapses and a contraction-relaxation motion is at work for approximately 2-3 revolutions of the system. During the contraction-relaxation motion of the heavy fluid, the unstable rotating cylindrical gravity currents behave similar to the stable ones. Towards the end of the contraction-relaxation motion, the dissipation rate in the system reaches a local minimum and a quasi-geostrophic equilibrium state is reached. After the quasi-geostrophic equilibrium state, vortex-wandering or vortex-splitting may occur depending on the ratio of Coriolis to inertia forces. The vortex-splitting process begins with non-axisymmetric bulges and, as the bulges grow, the kinetic energy increases at the expense of decreasing potential energy in the system. The completion of vortex-splitting is accompanied by a local maximum of dissipation rate and a local maximum of kinetic energy in the system. A striking feature of the unstable rotating cylindrical gravity currents is the persistent upwelling and downwelling motions, which are observed for both the

Structural Motion Grammar for Universal Use of Leap Motion: Amusement and Functional Contents Focused

Directory of Open Access Journals (Sweden)

Byungseok Lee

2018-01-01

Full Text Available Motions using Leap Motion controller are not standardized while the use of it is spreading in media contents. Each content defines its own motions, thereby creating confusion for users. Therefore, to alleviate user inconvenience, this study categorized the commonly used motion by Amusement and Functional Contents and defined the Structural Motion Grammar that can be universally used based on the classification. To this end, the Motion Lexicon was defined, which is a fundamental motion vocabulary, and an algorithm that enables real-time recognition of Structural Motion Grammar was developed. Moreover, the proposed method was verified by user evaluation and quantitative comparison tests.

Design of Fuzzy Enhanced Hierarchical Motion Stabilizing Controller of Unmanned Ground Vehicle in Three DimensionalSpace

Directory of Open Access Journals (Sweden)

Yue Ma

2011-12-01

Full Text Available In this paper, stabilizing control of tracked unmanned ground vehicle in 3-D space was presented. Firstly, models of major modules of tracked UGV were established. Next, to reveal the mechanism of disturbances applied on the UGV, two kinds of representative disturbances (slope and general disturbances in yaw motion were discussed in depth. Consequently, an attempting PID method was employed to compensate the impacts of disturbances andsimulation results proved the validity for disturbance incited by slope force, but revealed the lack for general disturbance on yaw motion. Finally, a hierarchical fuzzy controller combined with PID controller was proposed. In lower level, there were two PID controllers to compensate the disturbance of slope force, and on top level, the fuzzy logic controller was employed to correct the yaw motion error based on the differences between the model and the real UGV, which was able to guide the UGV maintain on the stable state. Simulation results demonstrated the excellent effectiveness of the newly designed controller.

Correlation-based motion vector processing with adaptive interpolation scheme for motion-compensated frame interpolation.

Science.gov (United States)

Huang, Ai-Mei; Nguyen, Truong

2009-04-01

In this paper, we address the problems of unreliable motion vectors that cause visual artifacts but cannot be detected by high residual energy or bidirectional prediction difference in motion-compensated frame interpolation. A correlation-based motion vector processing method is proposed to detect and correct those unreliable motion vectors by explicitly considering motion vector correlation in the motion vector reliability classification, motion vector correction, and frame interpolation stages. Since our method gradually corrects unreliable motion vectors based on their reliability, we can effectively discover the areas where no motion is reliable to be used, such as occlusions and deformed structures. We also propose an adaptive frame interpolation scheme for the occlusion areas based on the analysis of their surrounding motion distribution. As a result, the interpolated frames using the proposed scheme have clearer structure edges and ghost artifacts are also greatly reduced. Experimental results show that our interpolated results have better visual quality than other methods. In addition, the proposed scheme is robust even for those video sequences that contain multiple and fast motions.

A Method of Calculating Motion Error in a Linear Motion Bearing Stage

Directory of Open Access Journals (Sweden)

Gyungho Khim

2015-01-01

Full Text Available We report a method of calculating the motion error of a linear motion bearing stage. The transfer function method, which exploits reaction forces of individual bearings, is effective for estimating motion errors; however, it requires the rail-form errors. This is not suitable for a linear motion bearing stage because obtaining the rail-form errors is not straightforward. In the method described here, we use the straightness errors of a bearing block to calculate the reaction forces on the bearing block. The reaction forces were compared with those of the transfer function method. Parallelism errors between two rails were considered, and the motion errors of the linear motion bearing stage were measured and compared with the results of the calculations, revealing good agreement.

A Method of Calculating Motion Error in a Linear Motion Bearing Stage

Science.gov (United States)

Khim, Gyungho; Park, Chun Hong; Oh, Jeong Seok

2015-01-01

We report a method of calculating the motion error of a linear motion bearing stage. The transfer function method, which exploits reaction forces of individual bearings, is effective for estimating motion errors; however, it requires the rail-form errors. This is not suitable for a linear motion bearing stage because obtaining the rail-form errors is not straightforward. In the method described here, we use the straightness errors of a bearing block to calculate the reaction forces on the bearing block. The reaction forces were compared with those of the transfer function method. Parallelism errors between two rails were considered, and the motion errors of the linear motion bearing stage were measured and compared with the results of the calculations, revealing good agreement. PMID:25705715

Motion perception in motion : how we perceive object motion during smooth pursuit eye movements

NARCIS (Netherlands)

Souman, J.L.

2005-01-01

Eye movements change the retinal image motion of objects in the visual field. When we make an eye movement, the image of a stationary object will move across the retinae, while the retinal image of an object that we follow with the eyes is approximately stationary. To enable us to perceive motion in

Motion and relativity

CERN Document Server

Infeld, Leopold

1960-01-01

Motion and Relativity focuses on the methodologies, solutions, and approaches involved in the study of motion and relativity, including the general relativity theory, gravitation, and approximation.The publication first offers information on notation and gravitational interaction and the general theory of motion. Discussions focus on the notation of the general relativity theory, field values on the world-lines, general statement of the physical problem, Newton's theory of gravitation, and forms for the equation of motion of the second kind. The text then takes a look at the approximation meth

Predictive local receptive fields based respiratory motion tracking for motion-adaptive radiotherapy.

Science.gov (United States)

Yubo Wang; Tatinati, Sivanagaraja; Liyu Huang; Kim Jeong Hong; Shafiq, Ghufran; Veluvolu, Kalyana C; Khong, Andy W H

2017-07-01

Extracranial robotic radiotherapy employs external markers and a correlation model to trace the tumor motion caused by the respiration. The real-time tracking of tumor motion however requires a prediction model to compensate the latencies induced by the software (image data acquisition and processing) and hardware (mechanical and kinematic) limitations of the treatment system. A new prediction algorithm based on local receptive fields extreme learning machines (pLRF-ELM) is proposed for respiratory motion prediction. All the existing respiratory motion prediction methods model the non-stationary respiratory motion traces directly to predict the future values. Unlike these existing methods, the pLRF-ELM performs prediction by modeling the higher-level features obtained by mapping the raw respiratory motion into the random feature space of ELM instead of directly modeling the raw respiratory motion. The developed method is evaluated using the dataset acquired from 31 patients for two horizons in-line with the latencies of treatment systems like CyberKnife. Results showed that pLRF-ELM is superior to that of existing prediction methods. Results further highlight that the abstracted higher-level features are suitable to approximate the nonlinear and non-stationary characteristics of respiratory motion for accurate prediction.

The Importance of Spatiotemporal Information in Biological Motion Perception: White Noise Presented with a Step-like Motion Activates the Biological Motion Area.

Science.gov (United States)

Callan, Akiko; Callan, Daniel; Ando, Hiroshi

2017-02-01

Humans can easily recognize the motion of living creatures using only a handful of point-lights that describe the motion of the main joints (biological motion perception). This special ability to perceive the motion of animate objects signifies the importance of the spatiotemporal information in perceiving biological motion. The posterior STS (pSTS) and posterior middle temporal gyrus (pMTG) region have been established by many functional neuroimaging studies as a locus for biological motion perception. Because listening to a walking human also activates the pSTS/pMTG region, the region has been proposed to be supramodal in nature. In this study, we investigated whether the spatiotemporal information from simple auditory stimuli is sufficient to activate this biological motion area. We compared spatially moving white noise, having a running-like tempo that was consistent with biological motion, with stationary white noise. The moving-minus-stationary contrast showed significant differences in activation of the pSTS/pMTG region. Our results suggest that the spatiotemporal information of the auditory stimuli is sufficient to activate the biological motion area.

About the walking machine motion stability

Directory of Open Access Journals (Sweden)

V. V. Lapshin

2014-01-01

Full Text Available The use of legs as propulsive devices of the machine will increase its capability to cross rough and deformable terrain as compared with wheeled and trucked machines. Today it is already possible to speak about design of statically stable walking robots to be used in the certain areas of application. The most promising areas of their application are exploration and emergency-rescue operations in extremely complicated situations (e.g. in the zone of destruction after earthquakes, technogenic catastrophe, etc..In such dangerous situations there is a possibility for the walking machine to be overturned either because of loosing a support to one or several legs or due to significant displacement of the leg support points, which are caused by deformation or destruction of the terrain in the points of the legs support. Therefore, it is necessary to design motion control algorithms that enable teaching the motion control system of a walking robot: How to decrease the possibility of the robot overturning? How to stop the robot as quickly as possible keeping its static stability? What must be done if static stability is lost? Note that the loss of static stability does not inevitably result in the robot falling down. How to fall down better (with minimal robot destruction in inevitable case?This work investigates the first abovementioned problems, i.e. preventing a walking machine from overturning in dangerous situations. For this purpose it suggests to use a special cautious (safe gait, which allows the machine to remain statically stable if it suddenly looses support to its any leg. The natural price for the increased safety to prevent from overturning is the reduced capabilities of robot kinematics and, as a consequence, its capability to cross rough terrain. It is also suggested to reconsider the general definition of a walking machine static stability margin in order to obtain an adequate estimation of the robot overturning possibility

A thermodynamic study for the optimization of stable operation of free piston Stirling engines

Energy Technology Data Exchange (ETDEWEB)

Rogdakis, E.D.; Bormpilas, N.A.; Koniakos, I.K. [National Technical Univerisity, Athens (Greece). Dept. of Mechanical Engineering

2004-03-01

One of the most novel applications of the Stirling cycle is in the free piston configuration that was initially designed by W. Beale. In free piston Stirling engines (FPSEs), there are no mechanical linkages coupling the pistons or displacers, the motions of the reciprocating components follow the working gas pressure variations. Fillipo de Monte and G. Benvenuto have recently proposed a linearization technique of the dynamic balance equations. The aim of this paper is to predict the thermodynamic conditions for stable operation of FPSEs and their modeling. The equations of the angular velocity are solved analytically in terms of the working gas mass and the displacer-piston phase angle of the machine. Using the criterion of stable engine cyclic steady operation, a mathematically rigorous form is obtained for the main parameters of the engine. Furthermore, for simplicity reasons, thermodynamic magnitudes are obtained using the Schmidt analysis (isothermal model). (author)

A thermodynamic study for the optimization of stable operation of free piston Stirling engines

International Nuclear Information System (INIS)

Rogdakis, E.D.; Bormpilas, N.A.; Koniakos, I.K.

2004-01-01

One of the most novel applications of the Stirling cycle is in the free piston configuration that was initially designed by W. Beale. In free piston Stirling engines (FPSEs), there are no mechanical linkages coupling the pistons or displacers, the motions of the reciprocating components follow the working gas pressure variations. Fillipo de Monte and G. Benvenuto have recently proposed a linearization technique of the dynamic balance equations. The aim of this paper is to predict the thermodynamic conditions for stable operation of FPSEs and their modeling. The equations of the angular velocity are solved analytically in terms of the working gas mass and the displacer-piston phase angle of the machine. Using the criterion of stable engine cyclic steady operation, a mathematically rigorous form is obtained for the main parameters of the engine. Furthermore, for simplicity reasons, thermodynamic magnitudes are obtained using the Schmidt analysis (isothermal model)

Reduction of Motion Artifacts and Improvement of R Peak Detecting Accuracy Using Adjacent Non-Intrusive ECG Sensors

Directory of Open Access Journals (Sweden)

Minho Choi

2016-05-01

Full Text Available Non-intrusive electrocardiogram (ECG monitoring has many advantages: easy to measure and apply in daily life. However, motion noise in the measured signal is the major problem of non-intrusive measurement. This paper proposes a method to reduce the noise and to detect the R peaks of ECG in a stable manner in a sitting arrangement using non-intrusive sensors. The method utilizes two capacitive ECG sensors (cECGs to measure ECG, and another two cECGs located adjacent to the sensors for ECG are added to obtain the information on motion. Then, active noise cancellation technique and the motion information are used to reduce motion noise. To verify the proposed method, ECG was measured indoors and during driving, and the accuracy of the detected R peaks was compared. After applying the method, the sum of sensitivity and positive predictivity increased 8.39% on average and 26.26% maximally in the data. Based on the results, it was confirmed that the motion noise was reduced and that more reliable R peak positions could be obtained by the proposed method. The robustness of the new ECG measurement method will elicit benefits to various health care systems that require noninvasive heart rate or heart rate variability measurements.

Keeping speed and distance for aligned motion.

Science.gov (United States)

Farkas, Illés J; Kun, Jeromos; Jin, Yi; He, Gaoqi; Xu, Mingliang

2015-01-01

The cohesive collective motion (flocking, swarming) of autonomous agents is ubiquitously observed and exploited in both natural and man-made settings, thus, minimal models for its description are essential. In a model with continuous space and time we find that if two particles arrive symmetrically in a plane at a large angle, then (i) radial repulsion and (ii) linear self-propelling toward a fixed preferred speed are sufficient for them to depart at a smaller angle. For this local gain of momentum explicit velocity alignment is not necessary, nor are adhesion or attraction, inelasticity or anisotropy of the particles, or nonlinear drag. With many particles obeying these microscopic rules of motion we find that their spatial confinement to a square with periodic boundaries (which is an indirect form of attraction) leads to stable macroscopic ordering. As a function of the strength of added noise we see--at finite system sizes--a critical slowing down close to the order-disorder boundary and a discontinuous transition. After varying the density of particles at constant system size and varying the size of the system with constant particle density we predict that in the infinite system size (or density) limit the hysteresis loop disappears and the transition becomes continuous. We note that animals, humans, drones, etc., tend to move asynchronously and are often more responsive to motion than positions. Thus, for them velocity-based continuous models can provide higher precision than coordinate-based models. An additional characteristic and realistic feature of the model is that convergence to the ordered state is fastest at a finite density, which is in contrast to models applying (discontinuous) explicit velocity alignments and discretized time. To summarize, we find that the investigated model can provide a minimal description of flocking.

Motion Transplantation Techniques: A Survey

NARCIS (Netherlands)

van Basten, Ben; Egges, Arjan

2012-01-01

During the past decade, researchers have developed several techniques for transplanting motions. These techniques transplant a partial auxiliary motion, possibly defined for a small set of degrees of freedom, on a base motion. Motion transplantation improves motion databases' expressiveness and

A crawling robot driven by multi-stable origami

Science.gov (United States)

Pagano, Alexander; Yan, Tongxi; Chien, Brian; Wissa, A.; Tawfick, S.

2017-09-01

Using origami folding to construct and actuate mechanisms and machines offers attractive opportunities from small, scalable, and cheap robots to deployable adaptive structures. This paper presents the design of a bio-inspired origami crawling robot constructed by folding sheets of paper. The origami building block structure is based on the Kresling crease pattern (CP), a chiral tower with a polygonal base, which expands and contracts through coupled longitudinal and rotational motion similar to a screw. We design the origami to have multi-stable structural equilibria which can be tuned by changing the folding CP. Kinematic analysis of these structures based on rigid-plates and hinges at fold lines precludes the shape transformation associated with the bistability of the physical models. To capture the kinematics of the bi-stable origami, the panels’ deformation behavior is modeled utilizing principles of virtual folds. Virtual folds approximate material bending by hinged, rigid panels, which facilitates the development of a kinematic solution via rigid-plate rotation analysis. As such, the kinetics and stability of folded structures are investigated by assigning suitable torsional spring constants to the fold lines. The results presented demonstrate the effect of fold-pattern geometries on the snapping behavior of the bi-stable origami structure based on the Kresling pattern. The crawling robot is presented as a case study for the use of this origami structure to mimic crawling locomotion. The robot is comprised of two origami towers nested inside a paper bellow, and connected by 3D printed end plates. DC motors are used to actuate the expansion and contraction of the internal origami structures to achieve forward locomotion and steering. Beyond locomotion, this simple design can find applications in manipulators, booms, and active structures.

Objects in Motion

Science.gov (United States)

Damonte, Kathleen

2004-01-01

One thing scientists study is how objects move. A famous scientist named Sir Isaac Newton (1642-1727) spent a lot of time observing objects in motion and came up with three laws that describe how things move. This explanation only deals with the first of his three laws of motion. Newton's First Law of Motion says that moving objects will continue…

Simulation and experimental research on trans-media vehicle water-entry motion characteristics at low speed.

Science.gov (United States)

Yang, Jian; Li, Yongli; Feng, Jinfu; Hu, Junhua; Liu, An

2017-01-01

The motion characteristics of trans-media vehicles during the water-entry process were explored in this study in an effort to obtain the optimal water-entry condition of the vehicle for developing a novel, single control strategy integrating underwater non-control and in-air control. A water-entry dynamics model is established by combining the water-entry motion characteristics of the vehicle in uncontrolled conditions at low speed with time-varying parameters (e.g. buoyancy, added mass). A water-entry experiment is designed to confirm the effectiveness of the established model. After that, by comparing the experimental results with the simulated results, the model is further modified to more accurately reflect water-entry motion. The change laws of the vehicle's attitude and position during the water-entry process are also obtained by analyzing the simulation of the modified model under different velocity, angle, and angle of attack conditions. The results presented here have guiding significance for the future realization of reaching the stable underwater navigation state of the vehicle after water-entry process.

Simulation and experimental research on trans-media vehicle water-entry motion characteristics at low speed.

Directory of Open Access Journals (Sweden)

Jian Yang

Full Text Available The motion characteristics of trans-media vehicles during the water-entry process were explored in this study in an effort to obtain the optimal water-entry condition of the vehicle for developing a novel, single control strategy integrating underwater non-control and in-air control. A water-entry dynamics model is established by combining the water-entry motion characteristics of the vehicle in uncontrolled conditions at low speed with time-varying parameters (e.g. buoyancy, added mass. A water-entry experiment is designed to confirm the effectiveness of the established model. After that, by comparing the experimental results with the simulated results, the model is further modified to more accurately reflect water-entry motion. The change laws of the vehicle's attitude and position during the water-entry process are also obtained by analyzing the simulation of the modified model under different velocity, angle, and angle of attack conditions. The results presented here have guiding significance for the future realization of reaching the stable underwater navigation state of the vehicle after water-entry process.

Marker-Free Human Motion Capture

DEFF Research Database (Denmark)

Grest, Daniel

Human Motion Capture is a widely used technique to obtain motion data for animation of virtual characters. Commercial optical motion capture systems are marker-based. This book is about marker-free motion capture and its possibilities to acquire motion from a single viewing direction. The focus...

Kinematically stable bipedal locomotion using ionic polymer–metal composite actuators

International Nuclear Information System (INIS)

Hosseinipour, Milad; Elahinia, Mohammad

2013-01-01

Ionic conducting polymer–metal composites (abbreviated as IPMCs) are interesting actuators that can act as artificial muscles in robotic and microelectromechanical systems. Various black or gray box models have modeled the electrochemical–mechanical behavior of these materials. In this study, the governing partial differential equation of the behavior of IPMCs is solved using finite element methods to find the critical actuation parameters, such as strain distribution, maximum strain, and response time. One-dimensional results of the FEM solution are then extended to 2D to find the tip displacement of a flap actuator and experimentally verified. A model of a seven-degree-of-freedom biped robot, actuated by IPMC flaps, is then introduced. The possibility of fast and stable bipedal locomotion using IPMC artificial muscles is the main motivation of this study. Considering the actuator limits, joint path trajectories are generated to achieve a fast and smooth motion. The stability of the proposed gait is then evaluated using the ZMP criterion and motion simulation. The fabrication parameters of each actuator, such as length, platinum plating thickness and installation angle, are then determined using the generated trajectories. A discussion on future studies on force–torque generation of IPMCs for biped locomotion concludes this paper. (paper)

Respiratory impact on motion sickness induced by linear motion

NARCIS (Netherlands)

Mert, A.; Klöpping-Ketelaars, I.; Bles, W.

2009-01-01

Motion sickness incidence (MSI) for vertical sinusoidal motion reaches a maximum at 0.167 Hz. Normal breathing frequency is close to this frequency. There is some evidence for synchronization of breathing with this stimulus frequency. If this enforced breathing takes place over a larger frequency

Perception and the strongest sensory memory trace of multi-stable displays both form shortly after the stimulus onset.

Science.gov (United States)

Pastukhov, Alexander

2016-02-01

We investigated the relation between perception and sensory memory of multi-stable structure-from-motion displays. The latter is an implicit visual memory that reflects a recent history of perceptual dominance and influences only the initial perception of multi-stable displays. First, we established the earliest time point when the direction of an illusory rotation can be reversed after the display onset (29-114 ms). Because our display manipulation did not bias perception towards a specific direction of illusory rotation but only signaled the change in motion, this means that the perceptual dominance was established no later than 29-114 ms after the stimulus onset. Second, we used orientation-selectivity of sensory memory to establish which display orientation produced the strongest memory trace and when this orientation was presented during the preceding prime interval (80-140 ms). Surprisingly, both estimates point towards the time interval immediately after the display onset, indicating that both perception and sensory memory form at approximately the same time. This suggests a tighter integration between perception and sensory memory than previously thought, warrants a reconsideration of its role in visual perception, and indicates that sensory memory could be a unique behavioral correlate of the earlier perceptual inference that can be studied post hoc.

What motion is: William Neile and the laws of motion.

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Kemeny, Max

2017-07-01

In 1668-1669 William Neile and John Wallis engaged in a protracted correspondence regarding the nature of motion. Neile was unhappy with the laws of motion that had been established by the Royal Society in three papers published in 1668, deeming them not explanations of motion at all, but mere descriptions. Neile insisted that science could not be informative without a discussion of causes, meaning that Wallis's purely kinematic account of collision could not be complete. Wallis, however, did not consider Neile's objections to his work to be serious. Rather than engage in a discussion of the proper place of natural philosophy in science, Wallis decided to show how Neile's preferred treatment of motion lead to absurd conclusions. This dispute is offered as a case study of dispute resolution within the early Royal Society.

Early Improper Motion Detection in Golf Swings Using Wearable Motion Sensors: The First Approach

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Stančin, Sara; Tomažič, Sašo

2013-01-01

This paper presents an analysis of a golf swing to detect improper motion in the early phase of the swing. Led by the desire to achieve a consistent shot outcome, a particular golfer would (in multiple trials) prefer to perform completely identical golf swings. In reality, some deviations from the desired motion are always present due to the comprehensive nature of the swing motion. Swing motion deviations that are not detrimental to performance are acceptable. This analysis is conducted using a golfer's leading arm kinematic data, which are obtained from a golfer wearing a motion sensor that is comprised of gyroscopes and accelerometers. Applying the principal component analysis (PCA) to the reference observations of properly performed swings, the PCA components of acceptable swing motion deviations are established. Using these components, the motion deviations in the observations of other swings are examined. Any unacceptable deviations that are detected indicate an improper swing motion. Arbitrarily long observations of an individual player's swing sequences can be included in the analysis. The results obtained for the considered example show an improper swing motion in early phase of the swing, i.e., the first part of the backswing. An early detection method for improper swing motions that is conducted on an individual basis provides assistance for performance improvement. PMID:23752563

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.

Motion compensated digital tomosynthesis

NARCIS (Netherlands)

van der Reijden, Anneke; van Herk, Marcel; Sonke, Jan-Jakob

2013-01-01

Digital tomosynthesis (DTS) is a limited angle image reconstruction method for cone beam projections that offers patient surveillance capabilities during VMAT based SBRT delivery. Motion compensation (MC) has the potential to mitigate motion artifacts caused by respiratory motion, such as blur. The

An evaluation of control rod motion simulator of research reactor

International Nuclear Information System (INIS)

Sanda

2010-01-01

Motion simulator for rod control research reactor has been carried out using a servo motor. Reactor rod motion control at any point should be in the right position, one of the motors that can move in a precise and correct is the servo motor. To ensure that the servo motor to move in accordance with the desired program, then the servo motor function test should be carried out to ensure having good performance. Tests carried out on meshes stress disorder, the load is stable within a certain period and travel time safety control rod up and down, travel time regulating control rods up and down and travel time compensation control rods up and down. In testing the breakdown voltage V out nets at 24 V, 6.5 A with 12 Q load deviation obtained V0= V1 = 0.1% and 0.65% and for the stability of the load in a certain time deviation V = 0.7125% , next to the breakdown voltage V out nets at 12 V, 4.2 A with a 6 Q load deviation obtained V0= V1 = 0.275% and 1.158% for the stability of the load in a certain time deviation V = 1.463% and the net-voltage noise nets on V out 24 V, 4.5 A with 12 Q load deviation obtained V0 = V1 = 0.196% and 0.496% and for the stability of the load in a certain time deviation V = 0.3625%. While the travel time of a safety control rod up and down, up and down the regulator and compensation rise and fall showed a steady linear graph. The results show that the performance of the servo motor is very stable with the working area below the tolerance limit, it is 5% - 10%.(author)

Quantification of Esophageal Tumor Motion on Cine-Magnetic Resonance Imaging

Energy Technology Data Exchange (ETDEWEB)

Lever, Frederiek M.; Lips, Irene M.; Crijns, Sjoerd P.M.; Reerink, Onne; Lier, Astrid L.H.M.W. van; Moerland, Marinus A.; Vulpen, Marco van; Meijer, Gert J., E-mail: g.j.meijer@umcutrecht.nl

2014-02-01

Purpose: To quantify the movement of esophageal tumors noninvasively on cine-magnetic resonance imaging (MRI) by use of a semiautomatic method to visualize tumor movement directly throughout multiple breathing cycles. Methods and Materials: Thirty-six patients with esophageal tumors underwent MRI. Tumors were located in the upper (8), middle (7), and lower (21) esophagus. Cine-MR images were collected in the coronal and sagittal plane during 60 seconds at a rate of 2 Hz. An adaptive correlation filter was used to automatically track a previously marked reference point. Tumor movement was measured in the craniocaudal (CC), left–right (LR), and anteroposterior (AP) directions and its relationship along the longitudinal axis of the esophagus was investigated. Results: Tumor registration within the individual images was typically done at a millisecond time scale. The mean (SD) peak-to-peak displacements in the CC, AP, and LR directions were 13.3 (5.2) mm, 4.9 (2.5) mm, and 2.7 (1.2) mm, respectively. The bandwidth to cover 95% of excursions from the mean position (c95) was also calculated to exclude outliers caused by sporadic movements. The mean (SD) c95 values were 10.1 (3.8) mm, 3.7 (1.9) mm, and 2.0 (0.9) mm in the CC, AP, and LR dimensions. The end-exhale phase provided a stable position in the respiratory cycle, compared with more variety in the end-inhale phase. Furthermore, lower tumors showed more movement than did higher tumors in the CC and AP directions. Conclusions: Intrafraction tumor movement was highly variable between patients. Tumor position proved the most stable during the respiratory cycle in the end-exhale phase. A better understanding of tumor motion makes it possible to individualize radiation delivery strategies accordingly. Cine-MRI is a successful noninvasive modality to analyze motion for this purpose in the future.

Quantification of Esophageal Tumor Motion on Cine-Magnetic Resonance Imaging

International Nuclear Information System (INIS)

Lever, Frederiek M.; Lips, Irene M.; Crijns, Sjoerd P.M.; Reerink, Onne; Lier, Astrid L.H.M.W. van; Moerland, Marinus A.; Vulpen, Marco van; Meijer, Gert J.

2014-01-01

Purpose: To quantify the movement of esophageal tumors noninvasively on cine-magnetic resonance imaging (MRI) by use of a semiautomatic method to visualize tumor movement directly throughout multiple breathing cycles. Methods and Materials: Thirty-six patients with esophageal tumors underwent MRI. Tumors were located in the upper (8), middle (7), and lower (21) esophagus. Cine-MR images were collected in the coronal and sagittal plane during 60 seconds at a rate of 2 Hz. An adaptive correlation filter was used to automatically track a previously marked reference point. Tumor movement was measured in the craniocaudal (CC), left–right (LR), and anteroposterior (AP) directions and its relationship along the longitudinal axis of the esophagus was investigated. Results: Tumor registration within the individual images was typically done at a millisecond time scale. The mean (SD) peak-to-peak displacements in the CC, AP, and LR directions were 13.3 (5.2) mm, 4.9 (2.5) mm, and 2.7 (1.2) mm, respectively. The bandwidth to cover 95% of excursions from the mean position (c95) was also calculated to exclude outliers caused by sporadic movements. The mean (SD) c95 values were 10.1 (3.8) mm, 3.7 (1.9) mm, and 2.0 (0.9) mm in the CC, AP, and LR dimensions. The end-exhale phase provided a stable position in the respiratory cycle, compared with more variety in the end-inhale phase. Furthermore, lower tumors showed more movement than did higher tumors in the CC and AP directions. Conclusions: Intrafraction tumor movement was highly variable between patients. Tumor position proved the most stable during the respiratory cycle in the end-exhale phase. A better understanding of tumor motion makes it possible to individualize radiation delivery strategies accordingly. Cine-MRI is a successful noninvasive modality to analyze motion for this purpose in the future

Rolling Shutter Motion Deblurring

KAUST Repository

Su, Shuochen

2015-06-07

Although motion blur and rolling shutter deformations are closely coupled artifacts in images taken with CMOS image sensors, the two phenomena have so far mostly been treated separately, with deblurring algorithms being unable to handle rolling shutter wobble, and rolling shutter algorithms being incapable of dealing with motion blur. We propose an approach that delivers sharp and undis torted output given a single rolling shutter motion blurred image. The key to achieving this is a global modeling of the camera motion trajectory, which enables each scanline of the image to be deblurred with the corresponding motion segment. We show the results of the proposed framework through experiments on synthetic and real data.

Stochastic ground motion simulation

Science.gov (United States)

Rezaeian, Sanaz; Xiaodan, Sun; Beer, Michael; Kougioumtzoglou, Ioannis A.; Patelli, Edoardo; Siu-Kui Au, Ivan

2014-01-01

Strong earthquake ground motion records are fundamental in engineering applications. Ground motion time series are used in response-history dynamic analysis of structural or geotechnical systems. In such analysis, the validity of predicted responses depends on the validity of the input excitations. Ground motion records are also used to develop ground motion prediction equations(GMPEs) for intensity measures such as spectral accelerations that are used in response-spectrum dynamic analysis. Despite the thousands of available strong ground motion records, there remains a shortage of records for large-magnitude earthquakes at short distances or in specific regions, as well as records that sample specific combinations of source, path, and site characteristics.

Control of Respiratory Motion by Hypnosis Intervention during Radiotherapy of Lung Cancer I

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Rongmao Li

2013-01-01

Full Text Available The uncertain position of lung tumor during radiotherapy compromises the treatment effect. To effectively control respiratory motion during radiotherapy of lung cancer without any side effects, a novel control scheme, hypnosis, has been introduced in lung cancer treatment. In order to verify the suggested method, six volunteers were selected with a wide range of distribution of age, weight, and chest circumference. A set of experiments have been conducted for each volunteer, under the guidance of the professional hypnotist. All the experiments were repeated in the same environmental condition. The amplitude of respiration has been recorded under the normal state and hypnosis, respectively. Experimental results show that the respiration motion of volunteers in hypnosis has smaller and more stable amplitudes than in normal state. That implies that the hypnosis intervention can be an alternative way for respiratory control, which can effectively reduce the respiratory amplitude and increase the stability of respiratory cycle. The proposed method will find useful application in image-guided radiotherapy.

Control of Respiratory Motion by Hypnosis Intervention during Radiotherapy of Lung Cancer I

Science.gov (United States)

Deng, Jie; Xie, Yaoqin

2013-01-01

The uncertain position of lung tumor during radiotherapy compromises the treatment effect. To effectively control respiratory motion during radiotherapy of lung cancer without any side effects, a novel control scheme, hypnosis, has been introduced in lung cancer treatment. In order to verify the suggested method, six volunteers were selected with a wide range of distribution of age, weight, and chest circumference. A set of experiments have been conducted for each volunteer, under the guidance of the professional hypnotist. All the experiments were repeated in the same environmental condition. The amplitude of respiration has been recorded under the normal state and hypnosis, respectively. Experimental results show that the respiration motion of volunteers in hypnosis has smaller and more stable amplitudes than in normal state. That implies that the hypnosis intervention can be an alternative way for respiratory control, which can effectively reduce the respiratory amplitude and increase the stability of respiratory cycle. The proposed method will find useful application in image-guided radiotherapy. PMID:24093100

Motion Intention Analysis-Based Coordinated Control for Amputee-Prosthesis Interaction

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Fei Wang

2010-01-01

Full Text Available To study amputee-prosthesis (AP interaction, a novel reconfigurable biped robot was designed and fabricated. In homogeneous configuration, two identical artificial legs (ALs were used to simulate the symmetrical lower limbs of a healthy person. Linear inverted pendulum model combining with ZMP stability criterion was used to generate the gait trajectories of ALs. To acquire interjoint coordination for healthy gait, rate gyroscopes were mounted on CoGs of thigh and shank of both legs. By employing principal component analysis, the measured angular velocities were processed and the motion synergy was obtained in the final. Then, one of two ALs was replaced by a bionic leg (BL, and the biped robot was changed into heterogeneous configuration to simulate the AP coupling system. To realize symmetrical stable walking, master/slave coordinated control strategy is proposed. According to information acquired by gyroscopes, BL recognized the motion intention of AL and reconstructed its kinematic variables based on interjoint coordination. By employing iterative learning control, gait tracking of BL to AL was archived. Real environment robot walking experiments validated the correctness and effectiveness of the proposed scheme.

Novel true-motion estimation algorithm and its application to motion-compensated temporal frame interpolation.

Science.gov (United States)

Dikbas, Salih; Altunbasak, Yucel

2013-08-01

In this paper, a new low-complexity true-motion estimation (TME) algorithm is proposed for video processing applications, such as motion-compensated temporal frame interpolation (MCTFI) or motion-compensated frame rate up-conversion (MCFRUC). Regular motion estimation, which is often used in video coding, aims to find the motion vectors (MVs) to reduce the temporal redundancy, whereas TME aims to track the projected object motion as closely as possible. TME is obtained by imposing implicit and/or explicit smoothness constraints on the block-matching algorithm. To produce better quality-interpolated frames, the dense motion field at interpolation time is obtained for both forward and backward MVs; then, bidirectional motion compensation using forward and backward MVs is applied by mixing both elegantly. Finally, the performance of the proposed algorithm for MCTFI is demonstrated against recently proposed methods and smoothness constraint optical flow employed by a professional video production suite. Experimental results show that the quality of the interpolated frames using the proposed method is better when compared with the MCFRUC techniques.

Attraction of posture and motion-trajectory elements of conspecific biological motion in medaka fish.

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Shibai, Atsushi; Arimoto, Tsunehiro; Yoshinaga, Tsukasa; Tsuchizawa, Yuta; Khureltulga, Dashdavaa; Brown, Zuben P; Kakizuka, Taishi; Hosoda, Kazufumi

2018-06-05

Visual recognition of conspecifics is necessary for a wide range of social behaviours in many animals. Medaka (Japanese rice fish), a commonly used model organism, are known to be attracted by the biological motion of conspecifics. However, biological motion is a composite of both body-shape motion and entire-field motion trajectory (i.e., posture or motion-trajectory elements, respectively), and it has not been revealed which element mediates the attractiveness. Here, we show that either posture or motion-trajectory elements alone can attract medaka. We decomposed biological motion of the medaka into the two elements and synthesized visual stimuli that contain both, either, or none of the two elements. We found that medaka were attracted by visual stimuli that contain at least one of the two elements. In the context of other known static visual information regarding the medaka, the potential multiplicity of information regarding conspecific recognition has further accumulated. Our strategy of decomposing biological motion into these partial elements is applicable to other animals, and further studies using this technique will enhance the basic understanding of visual recognition of conspecifics.

41 CFR 60-30.8 - Motions; disposition of motions.

Science.gov (United States)

2010-07-01

... a supporting memorandum. Within 10 days after a written motion is served, or such other time period... writing. If made at the hearing, motions may be stated orally; but the Administrative Law Judge may require that they be reduced to writing and filed and served on all parties in the same manner as a formal...

A Fast Algorithm to Simulate Droplet Motions in Oil/Water Two Phase Flow

KAUST Repository

Zhang, Tao

2017-06-09

To improve the research methods in petroleum industry, we develop a fast algorithm to simulate droplet motions in oil and water two phase flow, using phase field model to describe the phase distribution in the flow process. An efficient partial difference equation solver—Shift-Matrix method is applied here, to speed up the calculation coding in high-level language, i.e. Matlab and R. An analytical solution of order parameter is derived, to define the initial condition of phase distribution. The upwind scheme is applied in our algorithm, to make it energy decay stable, which results in the fast speed of calculation. To make it more clear and understandable, we provide the specific code for forming the coefficient matrix used in Shift-Matrix Method. Our algorithm is compared with other methods in different scales, including Front Tracking and VOSET method in macroscopic and LBM method using RK model in mesoscopic scale. In addition, we compare the result of droplet motion under gravity using our algorithm with the empirical formula common used in industry. The result proves the high efficiency and robustness of our algorithm and it’s then used to simulate the motions of multiple droplets under gravity and cross-direction forces, which is more practical in industry and can be extended to wider application.

Effect of ship motions and flow stability in a small marine reactor driven by natural circulation

International Nuclear Information System (INIS)

Yoritsune, Tsutomu; Ishida, Toshihisa

2001-12-01

By using a small reactor as a power source for investigations and developments under sea, widely expanded activity is expectable. In this case, as for a nuclear reactor, small-size and lightweightness, and simplification of a system are needed with the safety. In JAERI, very small reactors for submersible research vessel (Deep-sea Reactor DRX and submersible Compact Reactor SCR) have been designed on the basis of needs investigation of sea research. Although the reactor is a PWR type, self-pressurization and natural circulation system are adopted in a primary system for small size and lightweightness. The fluid flow condition of the reactor core outlet is designed to be the two-phase with a low quality. Although the flow of a primary system is the two-phase flow with a low quality, the density wave oscillation may occur according to operating conditions. Moreover, since there are ship motions of heaving (the vertical direction acceleration) etc., when a submersible research vessel navigates on the sea surface, the circulation flow of the primary system is directly influenced by this external force. In order to maintain stable operations of the reactor, it is necessary to clarify effects of the flow stability characteristic of the primary coolant system and the external force. Until now, as for the flow stability of a nuclear reactor itself, many research reports have been published including the nuclear-coupled thermal oscillation of BWRs such as LaSalle-2, WNP-2 etc. As for the effect of external force, it is reported that the acceleration change based on a seismic wave affects the reactor core flow and the reactor power in a BWR. On the other hand, also in a PWR, since adoption of natural circulation cooling is considered for a generation 4 reactor, it is thought that the margin of the reactor core flow stability becomes an important parameter in the design. The reactor coolant flow mentioned in this report is the two-phase natural circulation flow coupled with

Visual search for motion-form conjunctions: is form discriminated within the motion system?

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von Mühlenen, A; Müller, H J

2001-06-01

Motion-form conjunction search can be more efficient when the target is moving (a moving 45 degrees tilted line among moving vertical and stationary 45 degrees tilted lines) rather than stationary. This asymmetry may be due to aspects of form being discriminated within a motion system representing only moving items, whereas discrimination of stationary items relies on a static form system (J. Driver & P. McLeod, 1992). Alternatively, it may be due to search exploiting differential motion velocity and direction signals generated by the moving-target and distractor lines. To decide between these alternatives, 4 experiments systematically varied the motion-signal information conveyed by the moving target and distractors while keeping their form difference salient. Moving-target search was found to be facilitated only when differential motion-signal information was available. Thus, there is no need to assume that form is discriminated within the motion system.

Effects of auditory information on self-motion perception during simultaneous presentation of visual shearing motion

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Tanahashi, Shigehito; Ashihara, Kaoru; Ujike, Hiroyasu

2015-01-01

Recent studies have found that self-motion perception induced by simultaneous presentation of visual and auditory motion is facilitated when the directions of visual and auditory motion stimuli are identical. They did not, however, examine possible contributions of auditory motion information for determining direction of self-motion perception. To examine this, a visual stimulus projected on a hemisphere screen and an auditory stimulus presented through headphones were presented separately or simultaneously, depending on experimental conditions. The participant continuously indicated the direction and strength of self-motion during the 130-s experimental trial. When the visual stimulus with a horizontal shearing rotation and the auditory stimulus with a horizontal one-directional rotation were presented simultaneously, the duration and strength of self-motion perceived in the opposite direction of the auditory rotation stimulus were significantly longer and stronger than those perceived in the same direction of the auditory rotation stimulus. However, the auditory stimulus alone could not sufficiently induce self-motion perception, and if it did, its direction was not consistent within each experimental trial. We concluded that auditory motion information can determine perceived direction of self-motion during simultaneous presentation of visual and auditory motion information, at least when visual stimuli moved in opposing directions (around the yaw-axis). We speculate that the contribution of auditory information depends on the plausibility and information balance of visual and auditory information. PMID:26113828

Orbit-attitude coupled motion around small bodies: Sun-synchronous orbits with Sun-tracking attitude motion

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Kikuchi, Shota; Howell, Kathleen C.; Tsuda, Yuichi; Kawaguchi, Jun'ichiro

2017-11-01

The motion of a spacecraft in proximity to a small body is significantly perturbed due to its irregular gravity field and solar radiation pressure. In such a strongly perturbed environment, the coupling effect of the orbital and attitude motions exerts a large influence that cannot be neglected. However, natural orbit-attitude coupled dynamics around small bodies that are stationary in both orbital and attitude motions have yet to be observed. The present study therefore investigates natural coupled motion that involves both a Sun-synchronous orbit and Sun-tracking attitude motion. This orbit-attitude coupled motion enables a spacecraft to maintain its orbital geometry and attitude state with respect to the Sun without requiring active control. Therefore, the proposed method can reduce the use of an orbit and attitude control system. This paper first presents analytical conditions to achieve Sun-synchronous orbits and Sun-tracking attitude motion. These analytical solutions are then numerically propagated based on non-linear coupled orbit-attitude equations of motion. Consequently, the possibility of implementing Sun-synchronous orbits with Sun-tracking attitude motion is demonstrated.

AQUA-motion domain and metaphorization patterns in European Portuguese: AQUA-motion metaphor in AERO-motion and abstract domains

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Hanna Jakubowicz Batoréo

2016-03-01

Full Text Available The AQUA-motion verbs – as studied by Majsak & Rahilina 2003 and 2007, Lander, Majsak & Rahilina [2005] 2008, 2012 and 2013, and Divjak & Lemmens 2007, and in European Portuguese (EP by Batoréo, 2007, 2008, 2009; Batoréo et al., 2007; Casadinho, 2007 – allow typically metaphorical uses, which we postulate can be organized in patterns. Our study shows that in European Portuguese there are two metaphorization patterns to be observed: (i AQUA-motion metaphor in AERO-motion domain and (ii AQUA-motion metaphor in abstract domain (e.g. abundance, arts, politics, etc.. In the first case, where the target domain of the metaphorization is the air, in EP we navigate through a crowd or we float in a waltz, whereas in the second, where it is abstract, we swim in money or in blood, and politicians navigate at sea or face floating currency in finances. In the present paper we survey the EP verbs of AQUA-motion metaphors in non-elicited data from electronically available language corpora (cf. Linguateca. In some cases comparisons are made with typologically diferent languages (as, e.g. Polish, cf. Prokofjeva’s 2007, Batoréo 2009.

"Bunched Black Swans" in Complex Geosystems: Cross-Disciplinary Approaches to the Additive and Multiplicative Modelling of Correlated Extreme Bursts

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Watkins, N. W.; Rypdal, M.; Lovsletten, O.

2012-12-01

-stationarity explicitly built in. In record breaking statistics, a record is defined in the sense used in everyday language, to be the largest value yet recorded in a time series, for example, the 2004 Sumatran Boxing Day earthquake was at the time the largest to be digitally recorded. The third group of approaches (e.g. avalanches) are explicitly spatiotemporal and so also include spatial structure. This presentation will discuss two examples of our recent work on the burst problem. We will show numerical results extending the preliminary results presented in [Watkins et al, PRE, 2009] using a standard additive model, linear fractional stable motion (LFSM). LFSM explicitly includes both heavy tails and long range dependence, allowing us to study how these 2 effects compete in determining the burst duration and size exponent probability distributions. We will contrast these simulations with new analytical studies of bursts in a multiplicative process, the multifractal random walk (MRW). We will present an analytical derivation for the scaling of the burst durations and make a preliminary comparison with data from the AE index from solar-terrestrial physics. We believe our result is more generally applicable than the MRW model, and that it applies to a broad class of multifractal processes.

Human Kinematics of Cochlear Implant Surgery: An Investigation of Insertion Micro-Motions and Speed Limitations.

Science.gov (United States)

Kesler, Kyle; Dillon, Neal P; Fichera, Loris; Labadie, Robert F

2017-09-01

Objectives Document human motions associated with cochlear implant electrode insertion at different speeds and determine the lower limit of continuous insertion speed by a human. Study Design Observational. Setting Academic medical center. Subjects and Methods Cochlear implant forceps were coupled to a frame containing reflective fiducials, which enabled optical tracking of the forceps' tip position in real time. Otolaryngologists (n = 14) performed mock electrode insertions at different speeds based on recommendations from the literature: "fast" (96 mm/min), "stable" (as slow as possible without stopping), and "slow" (15 mm/min). For each insertion, the following metrics were calculated from the tracked position data: percentage of time at prescribed speed, percentage of time the surgeon stopped moving forward, and number of direction reversals (ie, going from forward to backward motion). Results Fast insertion trials resulted in better adherence to the prescribed speed (45.4% of the overall time), no motion interruptions, and no reversals, as compared with slow insertions (18.6% of time at prescribed speed, 15.7% stopped time, and an average of 18.6 reversals per trial). These differences were statistically significant for all metrics ( P implant electrode at 15 mm/min is not feasible for human operators. The lower limit of continuous forward insertion is 52 mm/min on average. Guidelines on manual insertion kinematics should consider this practical limit of human motion.

Feasibility of Using Low-Cost Motion Capture for Automated Screening of Shoulder Motion Limitation after Breast Cancer Surgery.

Directory of Open Access Journals (Sweden)

Valeriya Gritsenko

Full Text Available To determine if a low-cost, automated motion analysis system using Microsoft Kinect could accurately measure shoulder motion and detect motion impairments in women following breast cancer surgery.Descriptive study of motion measured via 2 methods.Academic cancer center oncology clinic.20 women (mean age = 60 yrs were assessed for active and passive shoulder motions during a routine post-operative clinic visit (mean = 18 days after surgery following mastectomy (n = 4 or lumpectomy (n = 16 for breast cancer.Participants performed 3 repetitions of active and passive shoulder motions on the side of the breast surgery. Arm motion was recorded using motion capture by Kinect for Windows sensor and on video. Goniometric values were determined from video recordings, while motion capture data were transformed to joint angles using 2 methods (body angle and projection angle.Correlation of motion capture with goniometry and detection of motion limitation.Active shoulder motion measured with low-cost motion capture agreed well with goniometry (r = 0.70-0.80, while passive shoulder motion measurements did not correlate well. Using motion capture, it was possible to reliably identify participants whose range of shoulder motion was reduced by 40% or more.Low-cost, automated motion analysis may be acceptable to screen for moderate to severe motion impairments in active shoulder motion. Automatic detection of motion limitation may allow quick screening to be performed in an oncologist's office and trigger timely referrals for rehabilitation.

Feasibility of Using Low-Cost Motion Capture for Automated Screening of Shoulder Motion Limitation after Breast Cancer Surgery.

Science.gov (United States)

Gritsenko, Valeriya; Dailey, Eric; Kyle, Nicholas; Taylor, Matt; Whittacre, Sean; Swisher, Anne K

2015-01-01

To determine if a low-cost, automated motion analysis system using Microsoft Kinect could accurately measure shoulder motion and detect motion impairments in women following breast cancer surgery. Descriptive study of motion measured via 2 methods. Academic cancer center oncology clinic. 20 women (mean age = 60 yrs) were assessed for active and passive shoulder motions during a routine post-operative clinic visit (mean = 18 days after surgery) following mastectomy (n = 4) or lumpectomy (n = 16) for breast cancer. Participants performed 3 repetitions of active and passive shoulder motions on the side of the breast surgery. Arm motion was recorded using motion capture by Kinect for Windows sensor and on video. Goniometric values were determined from video recordings, while motion capture data were transformed to joint angles using 2 methods (body angle and projection angle). Correlation of motion capture with goniometry and detection of motion limitation. Active shoulder motion measured with low-cost motion capture agreed well with goniometry (r = 0.70-0.80), while passive shoulder motion measurements did not correlate well. Using motion capture, it was possible to reliably identify participants whose range of shoulder motion was reduced by 40% or more. Low-cost, automated motion analysis may be acceptable to screen for moderate to severe motion impairments in active shoulder motion. Automatic detection of motion limitation may allow quick screening to be performed in an oncologist's office and trigger timely referrals for rehabilitation.

Designing a compact MRI motion phantom

Directory of Open Access Journals (Sweden)

Schmiedel Max

2016-09-01

Full Text Available Even today, dealing with motion artifacts in magnetic resonance imaging (MRI is a challenging task. Image corruption due to spontaneous body motion complicates diagnosis. In this work, an MRI phantom for rigid motion is presented. It is used to generate motion-corrupted data, which can serve for evaluation of blind motion compensation algorithms. In contrast to commercially available MRI motion phantoms, the presented setup works on small animal MRI systems. Furthermore, retrospective gating is performed on the data, which can be used as a reference for novel motion compensation approaches. The motion of the signal source can be reconstructed using motor trigger signals and be utilized as the ground truth for motion estimation. The proposed setup results in motion corrected images. Moreover, the importance of preprocessing the MRI raw data, e.g. phase-drift correction, is demonstrated. The gained knowledge can be used to design an MRI phantom for elastic motion.

12 CFR 747.23 - Motions.

Science.gov (United States)

2010-01-01

... written motions except as otherwise directed by the administrative law judge. Written memorandum, briefs... Procedure § 747.23 Motions. (a) In writing. (1) Except as otherwise provided herein, an application or request for an order or ruling must be made by written motion. (2) All written motions must state with...

Brain Image Motion Correction

DEFF Research Database (Denmark)

Jensen, Rasmus Ramsbøl; Benjaminsen, Claus; Larsen, Rasmus

2015-01-01

The application of motion tracking is wide, including: industrial production lines, motion interaction in gaming, computer-aided surgery and motion correction in medical brain imaging. Several devices for motion tracking exist using a variety of different methodologies. In order to use such devices...... offset and tracking noise in medical brain imaging. The data are generated from a phantom mounted on a rotary stage and have been collected using a Siemens High Resolution Research Tomograph for positron emission tomography. During acquisition the phantom was tracked with our latest tracking prototype...

Motion-to-Motion Gauge for the Electroweak Interaction of Leptons

Directory of Open Access Journals (Sweden)

Tselnik F.

2015-01-01

Full Text Available Comprised of rods and clocks, a reference system is a mere intermediary between the motion that is of interest in the problem and the motions of auxiliary test bodies the reference system is to be gauged with. However, a theory base d on such reference sys- tems might hide some features of this actual motion-to-motion correspondence, thus leaving these features incomprehensible. It is therefore d esirable to consider this corre- spondence explicitly, if only to substantiate a particular scheme. To this end, the very existence of a (local top-speed signal is shown to be sufficient to explain some peculiar- ities of the weak interaction using symmetrical configurations of auxiliary trajectories as a means for the gauge. In particular, the unification of the electromagnetic and weak interactions, parity violation, SU(2 L × U(1 group structure with the values of its cou- pling constants, and the intermediate vector boson are found to be a direct consequence of this gauge procedure.

Leg-adjustment strategies for stable running in three dimensions

International Nuclear Information System (INIS)

Peuker, Frank; Maufroy, Christophe; Seyfarth, André

2012-01-01

The dynamics of the center of mass (CoM) in the sagittal plane in humans and animals during running is well described by the spring-loaded inverted pendulum (SLIP). With appropriate parameters, SLIP running patterns are stable, and these models can recover from perturbations without the need for corrective strategies, such as the application of additional forces. Rather, it is sufficient to adjust the leg to a fixed angle relative to the ground. In this work, we consider the extension of the SLIP to three dimensions (3D SLIP) and investigate feed-forward strategies for leg adjustment during the flight phase. As in the SLIP model, the leg is placed at a fixed angle. We extend the scope of possible reference axes from only fixed horizontal and vertical axes to include the CoM velocity vector as a movement-related reference, resulting in six leg-adjustment strategies. Only leg-adjustment strategies that include the CoM velocity vector produced stable running and large parameter domains of stability. The ability of the model to recover from perturbations along the direction of motion (directional stability) depended on the strategy for lateral leg adjustment. Specifically, asymptotic and neutral directional stability was observed for strategies based on the global reference axis and the velocity vector, respectively. Additional features of velocity-based leg adjustment are running at arbitrary low speed (kinetic energy) and the emergence of large domains of stable 3D running that are smoothly transferred to 2D SLIP stability and even to 1D SLIP hopping. One of the additional leg-adjustment strategies represented a large convex region of parameters where stable and robust hopping and running patterns exist. Therefore, this strategy is a promising candidate for implementation into engineering applications, such as robots, for instance. In a preliminary comparison, the model predictions were in good agreement with the experimental data, suggesting that the 3D SLIP is an

Initial experience with active breathing control of liver motion during ventilation

International Nuclear Information System (INIS)

Robertson, John M.; Sharpe, Michael B.; Jaffray, David A.; Wong, John W.

1997-01-01

Purpose: Recent evidence has shown that some patients with hepatic tumors can be safely irradiated to a dose well over twice the whole liver tolerance dose if portions of normal liver are spared. Correction during treatment planning for the ventilatory motion of the liver can add a large volume of normal liver to the planning target volume. Any reduction in ventilatory motion has the potential to allow a higher dose of radiation to be given safely. Active Breathing Control (ABC) can be used to temporarily stop the airflow to a patient, thus immobilizing the liver, at any part of a patient's ventilatory cycle. ABC during helical CT scanning can be used to study the full three dimensional motion of the liver and other abdominal organs during ventilation. Ultimately, if the use of ABC is found to be clinically feasible, tolerable for patients, and, most importantly, reproducible over time, then ABC may be used during radiation treatment. Materials and Methods: An ABC apparatus was constructed using a flow monitor and scissor valves on both the inhalation and exhalation paths to the patient. The patient breathed through either a mouthpiece or facemask during the procedure. The ventilatory cycle was displayed in real time. When a stable breathing pattern was observed, the ABC was activated at a specific lung volume, closing both scissors valves, and preventing ventilation. The length of time for comfortable activation of the ABC machine for the individual patient was determined during a teaching and practice period prior to CT scanning. Helical CT scans (slice thickness 0.5 cm) to assess the potential benefit of immobilizing breathing were obtained for normal breathing, end-inspiration and end-expiration. The reproducibility of ABC over time was assessed by repeating the end-inspiration scan both immediately and one week later. The contours of the liver and kidneys were entered for each study. Results: Five patients have undergone ABC study of the abdomen. End

Characterization of design ground motion for the central and eastern United States: licensing implications

International Nuclear Information System (INIS)

Litehiser, J.; Carrato, P.

2005-01-01

For the first time in decades several US utilities are exploring the possibility of building new Nuclear Power Plant (NPP) generating capacity in the Central and Eastern United States (CEUS). Among the many topics that must be considered to license a nuclear plant (NPP) is appropriate design to mitigate the potential effects of vibratory ground motion from earthquakes. Agreement on seismic design ground motion was not always easy during licensing of the last generation of NPPs. Therefore, over the last few decades both industry and the United States Nuclear Regulatory Commission (USNRC) have worked to find ground motion criteria that recognize and overcome earlier licensing difficulties. Such criteria should be stable and easily implemented. Important and complementary programs under the direction of the Lawrence Livermore National Laboratory (LLNL) and the Electric Power Research Institute (EPRI) were part of this effort, and these studies resulted in probabilistic seismic hazard assessments (PSHAs) for a number of CEUS NPP sites. These results and the concepts underlying them are now incorporated into both USNRC regulation and regulatory guidance. Nevertheless, as the utilities and the NRC begin a renewed licensing dialog, issues of regulatory interpretation of earthquake ground motion design criteria have emerged. These issues are as fundamental as the shape and amplitude of ground motion design response spectra and as significant as the impact of these spectra on structural design. Successful and timely resolution of these issues will significantly impact the future of nuclear power in the US. The purpose of this paper is to briefly describe some of these issues and the approaches that have been proposed for their resolution. (authors)

6 CFR 13.28 - Motions.

Science.gov (United States)

2010-01-01

... 6 Domestic Security 1 2010-01-01 2010-01-01 false Motions. 13.28 Section 13.28 Domestic Security DEPARTMENT OF HOMELAND SECURITY, OFFICE OF THE SECRETARY PROGRAM FRAUD CIVIL REMEDIES § 13.28 Motions. (a) Any application to the ALJ for an order or ruling will be by motion. Motions will state the relief...

7 CFR 1.327 - Motions.

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2010-01-01

... be in writing. The ALJ may require that oral motions be reduced to writing. (c) The ALJ may require written motions to be accompanied by supporting memorandums. (d) Within 15 days after a written motion is...) The ALJ may not grant a written motion prior to expiration of the time for filing responses thereto...

Multiturn extraction and injection by means of adiabatic capture in stable islands of phase space

Directory of Open Access Journals (Sweden)

R. Cappi

2004-02-01

Full Text Available Recently a novel approach has been proposed for performing multiturn extraction from a circular machine. Such a technique consists of splitting the beam by means of stable islands created in transverse phase space by magnetic elements creating nonlinear fields, such as sextupoles and octupoles. Provided a slow time variation of the linear tune is applied, adiabatic with respect to the betatron motion, the islands can be moved in phase space and eventually charged particles may be trapped inside the stable structures. This generates a certain number of well-separated beamlets. Originally, this principle was successfully tested using a fourth-order resonance. In this paper the approach is generalized by considering other types of resonances as well as the possibility of performing multiple multiturn extractions. The results of numerical simulations are presented and described in detail. Of course, by time reversal, the proposed approach could be used also for multiturn injection.

Sound-contingent visual motion aftereffect

Directory of Open Access Journals (Sweden)

Kobayashi Maori

2011-05-01

Full Text Available Abstract Background After a prolonged exposure to a paired presentation of different types of signals (e.g., color and motion, one of the signals (color becomes a driver for the other signal (motion. This phenomenon, which is known as contingent motion aftereffect, indicates that the brain can establish new neural representations even in the adult's brain. However, contingent motion aftereffect has been reported only in visual or auditory domain. Here, we demonstrate that a visual motion aftereffect can be contingent on a specific sound. Results Dynamic random dots moving in an alternating right or left direction were presented to the participants. Each direction of motion was accompanied by an auditory tone of a unique and specific frequency. After a 3-minutes exposure, the tones began to exert marked influence on the visual motion perception, and the percentage of dots required to trigger motion perception systematically changed depending on the tones. Furthermore, this effect lasted for at least 2 days. Conclusions These results indicate that a new neural representation can be rapidly established between auditory and visual modalities.

Level-set simulations of buoyancy-driven motion of single and multiple bubbles

International Nuclear Information System (INIS)

Balcázar, Néstor; Lehmkuhl, Oriol; Jofre, Lluís; Oliva, Assensi

2015-01-01

Highlights: • A conservative level-set method is validated and verified. • An extensive study of buoyancy-driven motion of single bubbles is performed. • The interactions of two spherical and ellipsoidal bubbles is studied. • The interaction of multiple bubbles is simulated in a vertical channel. - Abstract: This paper presents a numerical study of buoyancy-driven motion of single and multiple bubbles by means of the conservative level-set method. First, an extensive study of the hydrodynamics of single bubbles rising in a quiescent liquid is performed, including its shape, terminal velocity, drag coefficients and wake patterns. These results are validated against experimental and numerical data well established in the scientific literature. Then, a further study on the interaction of two spherical and ellipsoidal bubbles is performed for different orientation angles. Finally, the interaction of multiple bubbles is explored in a periodic vertical channel. The results show that the conservative level-set approach can be used for accurate modelling of bubble dynamics. Moreover, it is demonstrated that the present method is numerically stable for a wide range of Morton and Reynolds numbers.

Gravitational self-force correction to the innermost stable circular equatorial orbit of a Kerr black hole.

Science.gov (United States)

Isoyama, Soichiro; Barack, Leor; Dolan, Sam R; Le Tiec, Alexandre; Nakano, Hiroyuki; Shah, Abhay G; Tanaka, Takahiro; Warburton, Niels

2014-10-17

For a self-gravitating particle of mass μ in orbit around a Kerr black hole of mass M ≫ μ, we compute the O(μ/M) shift in the frequency of the innermost stable circular equatorial orbit due to the conservative piece of the gravitational self-force acting on the particle. Our treatment is based on a Hamiltonian formulation of the dynamics in terms of geodesic motion in a certain locally defined effective smooth spacetime. We recover the same result using the so-called first law of binary black-hole mechanics. We give numerical results for the innermost stable circular equatorial orbit frequency shift as a function of the black hole's spin amplitude, and compare with predictions based on the post-Newtonian approximation and the effective one-body model. Our results provide an accurate strong-field benchmark for spin effects in the general-relativistic two-body problem.

Dipteran insect flight dynamics. Part 1 Longitudinal motion about hover.

Science.gov (United States)

Faruque, Imraan; Sean Humbert, J

2010-05-21

This paper presents a reduced-order model of longitudinal hovering flight dynamics for dipteran insects. The quasi-steady wing aerodynamics model is extended by including perturbation states from equilibrium and paired with rigid body equations of motion to create a nonlinear simulation of a Drosophila-like insect. Frequency-based system identification tools are used to identify the transfer functions from biologically inspired control inputs to rigid body states. Stability derivatives and a state space linear system describing the dynamics are also identified. The vehicle control requirements are quantified with respect to traditional human pilot handling qualities specification. The heave dynamics are found to be decoupled from the pitch/fore/aft dynamics. The haltere-on system revealed a stabilized system with a slow (heave) and fast subsidence mode, and a stable oscillatory mode. The haltere-off (bare airframe) system revealed a slow (heave) and fast subsidence mode and an unstable oscillatory mode, a modal structure in agreement with CFD studies. The analysis indicates that passive aerodynamic mechanisms contribute to stability, which may help explain how insects are able to achieve stable locomotion on a very small computational budget. Copyright (c) 2010. Published by Elsevier Ltd.

Performance characterization of Watson Ahumada motion detector using random dot rotary motion stimuli.

Directory of Open Access Journals (Sweden)

Siddharth Jain

Full Text Available The performance of Watson & Ahumada's model of human visual motion sensing is compared against human psychophysical performance. The stimulus consists of random dots undergoing rotary motion, displayed in a circular annulus. The model matches psychophysical observer performance with respect to most parameters. It is able to replicate some key psychophysical findings such as invariance of observer performance to dot density in the display, and decrease of observer performance with frame duration of the display.Associated with the concept of rotary motion is the notion of a center about which rotation occurs. One might think that for accurate estimation of rotary motion in the display, this center must be accurately known. A simple vector analysis reveals that this need not be the case. Numerical simulations confirm this result, and may explain the position invariance of MST(d cells. Position invariance is the experimental finding that rotary motion sensitive cells are insensitive to where in their receptive field rotation occurs.When all the dots in the display are randomly drawn from a uniform distribution, illusory rotary motion is perceived. This case was investigated by Rose & Blake previously, who termed the illusory rotary motion the omega effect. Two important experimental findings are reported concerning this effect. First, although the display of random dots evokes perception of rotary motion, the direction of motion perceived does not depend on what dot pattern is shown. Second, the time interval between spontaneous flips in perceived direction is lognormally distributed (mode approximately 2 s. These findings suggest the omega effect fits in the category of a typical bistable illusion, and therefore the processes that give rise to this illusion may be the same processes that underlie much of other bistable phenomenon.

Smoothing of respiratory motion traces for motion-compensated radiotherapy.

Science.gov (United States)

Ernst, Floris; Schlaefer, Alexander; Schweikard, Achim

2010-01-01

The CyberKnife system has been used successfully for several years to radiosurgically treat tumors without the need for stereotactic fixation or sedation of the patient. It has been shown that tumor motion in the lung, liver, and pancreas can be tracked with acceptable accuracy and repeatability. However, highly precise targeting for tumors in the lower abdomen, especially for tumors which exhibit strong motion, remains problematic. Reasons for this are manifold, like the slow tracking system operating at 26.5 Hz, and using the signal from the tracking camera "as is." Since the motion recorded with the camera is used to compensate for system latency by prediction and the predicted signal is subsequently used to infer the tumor position from a correlation model based on x-ray imaging of gold fiducials around the tumor, camera noise directly influences the targeting accuracy. The goal of this work is to establish the suitability of a new smoothing method for respiratory motion traces used in motion-compensated radiotherapy. The authors endeavor to show that better prediction--With a lower rms error of the predicted signal--and/or smoother prediction is possible using this method. The authors evaluated six commercially available tracking systems (NDI Aurora, PolarisClassic, Polaris Vicra, MicronTracker2 H40, FP5000, and accuTrack compact). The authors first tracked markers both stationary and while in motion to establish the systems' noise characteristics. Then the authors applied a smoothing method based on the a trous wavelet decomposition to reduce the devices' noise level. Additionally, the smoothed signal of the moving target and a motion trace from actual human respiratory motion were subjected to prediction using the MULIN and the nLMS2 algorithms. The authors established that the noise distribution for a static target is Gaussian and that when the probe is moved such as to mimic human respiration, it remains Gaussian with the exception of the FP5000 and the

Smoothing of respiratory motion traces for motion-compensated radiotherapy

International Nuclear Information System (INIS)

Ernst, Floris; Schlaefer, Alexander; Schweikard, Achim

2010-01-01

Purpose: The CyberKnife system has been used successfully for several years to radiosurgically treat tumors without the need for stereotactic fixation or sedation of the patient. It has been shown that tumor motion in the lung, liver, and pancreas can be tracked with acceptable accuracy and repeatability. However, highly precise targeting for tumors in the lower abdomen, especially for tumors which exhibit strong motion, remains problematic. Reasons for this are manifold, like the slow tracking system operating at 26.5 Hz, and using the signal from the tracking camera ''as is''. Since the motion recorded with the camera is used to compensate for system latency by prediction and the predicted signal is subsequently used to infer the tumor position from a correlation model based on x-ray imaging of gold fiducials around the tumor, camera noise directly influences the targeting accuracy. The goal of this work is to establish the suitability of a new smoothing method for respiratory motion traces used in motion-compensated radiotherapy. The authors endeavor to show that better prediction--With a lower rms error of the predicted signal--and/or smoother prediction is possible using this method. Methods: The authors evaluated six commercially available tracking systems (NDI Aurora, PolarisClassic, Polaris Vicra, MicronTracker2 H40, FP5000, and accuTrack compact). The authors first tracked markers both stationary and while in motion to establish the systems' noise characteristics. Then the authors applied a smoothing method based on the a trous wavelet decomposition to reduce the devices' noise level. Additionally, the smoothed signal of the moving target and a motion trace from actual human respiratory motion were subjected to prediction using the MULIN and the nLMS 2 algorithms. Results: The authors established that the noise distribution for a static target is Gaussian and that when the probe is moved such as to mimic human respiration, it remains Gaussian with the

Semi-active Control of Shallow Cables with Magnetorheological Dampers under Harmonic Axial Support Motion

DEFF Research Database (Denmark)

Zhou, Q.; Nielsen, Søren R.K.; Qu, W.L.

2007-01-01

amplitude is located in a certain range for the case OE2o1/3, the original zero out-of-plane vibration of the cable should be changed to the stable in-plane and out-of-plane coupled oscillation by using the optimal passive viscous damper or the MR damper with the SA-1 rule. It is also observed...... to the first in-plane eigenmode of the cable. The numerical results show that the MR damper with the SA-1 rule and the optimal viscous damper perform similarly to mitigate the vibration of the cable under axial periodic support motion, and, in some cases, the SA-2 rule is more favourable in suppressing...... the cable vibration compared with the SA-1 rule. In the final analysis, both the MR damper and the viscous damper can effectively mitigate the out-of-plane component of the cable, while having little effect on the reduction of the in-plane response in most cases. Furthermore, when the support motion...

Audiovisual biofeedback improves the correlation between internal/external surrogate motion and lung tumor motion.

Science.gov (United States)

Lee, Danny; Greer, Peter B; Paganelli, Chiara; Ludbrook, Joanna Jane; Kim, Taeho; Keall, Paul

2018-03-01

Breathing management can reduce breath-to-breath (intrafraction) and day-by-day (interfraction) variability in breathing motion while utilizing the respiratory motion of internal and external surrogates for respiratory guidance. Audiovisual (AV) biofeedback, an interactive personalized breathing motion management system, has been developed to improve reproducibility of intra- and interfraction breathing motion. However, the assumption of the correlation of respiratory motion between surrogates and tumors is not always verified during medical imaging and radiation treatment. Therefore, the aim of the study was to test the hypothesis that the correlation of respiratory motion between surrogates and tumors is the same under free breathing without guidance (FB) and with AV biofeedback guidance for voluntary motion management. For 13 lung cancer patients receiving radiotherapy, 2D coronal and sagittal cine-MR images were acquired across two MRI sessions (pre- and mid-treatment) with two breathing conditions: (a) FB and (b) AV biofeedback, totaling 88 patient measurements. Simultaneously, the external respiratory motion of the abdomen was measured. The internal respiratory motion of the diaphragm and lung tumor was retrospectively measured from 2D coronal and sagittal cine-MR images. The correlation of respiratory motion between surrogates and tumors was calculated using Pearson's correlation coefficient for: (a) abdomen to tumor (abdomen-tumor) and (b) diaphragm to tumor (diaphragm-tumor). The correlations were compared between FB and AV biofeedback using several metrics: abdomen-tumor and diaphragm-tumor correlations with/without ≥5 mm tumor motion range and with/without adjusting for phase shifts between the signals. Compared to FB, AV biofeedback improved abdomen-tumor correlation by 11% (p = 0.12) from 0.53 to 0.59 and diaphragm-tumor correlation by 13% (p = 0.02) from 0.55 to 0.62. Compared to FB, AV biofeedback improved abdomen-tumor correlation by 17% (p = 0

Human motion simulation predictive dynamics

CERN Document Server

Abdel-Malek, Karim

2013-01-01

Simulate realistic human motion in a virtual world with an optimization-based approach to motion prediction. With this approach, motion is governed by human performance measures, such as speed and energy, which act as objective functions to be optimized. Constraints on joint torques and angles are imposed quite easily. Predicting motion in this way allows one to use avatars to study how and why humans move the way they do, given specific scenarios. It also enables avatars to react to infinitely many scenarios with substantial autonomy. With this approach it is possible to predict dynamic motion without having to integrate equations of motion -- rather than solving equations of motion, this approach solves for a continuous time-dependent curve characterizing joint variables (also called joint profiles) for every degree of freedom. Introduces rigorous mathematical methods for digital human modelling and simulation Focuses on understanding and representing spatial relationships (3D) of biomechanics Develops an i...

A study of the nucleus-nucleus total reaction cross section of stable systems at intermediate energies: An application to 12C

Science.gov (United States)

Hu, Liyuan; Song, Yushou; Hou, Yingwei; Liu, Huilan; Li, Hui

2018-07-01

A semi-microscopic analytical expression of the nucleus-nucleus total reaction cross section (σR) was proposed based on the strong absorption model. It is suitable for stable nuclei at intermediate energies. The matter density distributions of nuclei and the nucleon-nucleon total cross section were both considered. Particularly, the Fermi motion effect of the nucleons in a nucleus was also taken into account. The parametrization of σR was applied to the colliding systems including 12C. The experimental data at energies from 30 to 1000 MeV/nucleon were well reproduced, according to which an approach of deriving σR without adjustable parameters was developed. The necessity of considering the Fermi motion effect in the parametrization was discussed.

Hamiltonian Formulation and Perturbations for Dust Motion Around Cometary Nuclei

Science.gov (United States)

Jiang, Yu; Schmidt, Juergen; Baoyin, Hexi; Li, Hengnian; Li, Junfeng

2017-12-01

In this paper we analyze the dynamical behavior of large dust grains in the vicinity of a cometary nucleus. To this end we consider the gravitational field of the irregularly shaped body, as well as its electric and magnetic fields. Without considering the effect of gas friction and solar radiation, we find that there exist grains which are static relative to the cometary nucleus; the positions of these grains are the stable equilibria. There also exist grains in the stable periodic orbits close to the cometary nucleus. The grains in the stable equilibria or the stable periodic orbits won't escape or impact on the surface of the cometary nucleus. The results are applicable for large charge dusts with small area-mass ratio which are near the cometary nucleus and far from the Solar. It is found that the resonant periodic orbit can be stable, and there exist stable non-resonant periodic orbits, stable resonant periodic orbits and unstable resonant periodic orbits in the potential field of cometary nuclei. The comet gravity force, solar gravity force, electric force, magnetic force, solar radiation pressure, as well as the gas drag force are all considered to analyze the order of magnitude of these forces acting on the grains with different parameters. Let the distance of the dust grain relative to the mass centre of the cometary nucleus, the charge and the mass of the dust grain vary, respectively, fix other parameters, we calculated the strengths of different forces. The motion of the dust grain depends on the area-mass ratio, the charge, and the distance relative to the comet's mass center. For a large dust grain (> 1 mm) close to the cometary nucleus which has a small value of area-mass ratio, the comet gravity is the largest force acting on the dust grain. For a small dust grain (< 1 mm) close to the cometary nucleus with large value of area-mass ratio, both the solar radiation pressure and the comet gravity are two major forces. If the a small dust grain which is

Stable Trapping of Multielectron Helium Bubbles in a Paul Trap

Science.gov (United States)

Joseph, E. M.; Vadakkumbatt, V.; Pal, A.; Ghosh, A.

2017-06-01

In a recent experiment, we have used a linear Paul trap to store and study multielectron bubbles (MEBs) in liquid helium. MEBs have a charge-to-mass ratio (between 10^{-4} and 10^{-2} C/kg) which is several orders of magnitude smaller than ions (between 10^6 and 10^8 C/kg) studied in traditional ion traps. In addition, MEBs experience significant drag force while moving through the liquid. As a result, the experimental parameters for stable trapping of MEBs, such as magnitude and frequency of the applied electric fields, are very different from those used in typical ion trap experiments. The purpose of this paper is to model the motion of MEBs inside a linear Paul trap in liquid helium, determine the range of working parameters of the trap, and compare the results with experiments.

Integration Method of Emphatic Motions and Adverbial Expressions with Scalar Parameters for Robotic Motion Coaching System

Science.gov (United States)

Okuno, Keisuke; Inamura, Tetsunari

A robotic coaching system can improve humans' learning performance of motions by intelligent usage of emphatic motions and adverbial expressions according to user reactions. In robotics, however, method to control both the motions and the expressions and how to bind them had not been adequately discussed from an engineering point of view. In this paper, we propose a method for controlling and binding emphatic motions and adverbial expressions by using two scalar parameters in a phase space. In the phase space, variety of motion patterns and verbal expressions are connected and can be expressed as static points. We show the feasibility of the proposing method through experiments of actual sport coaching tasks for beginners. From the results of participants' improvements in motion learning, we confirmed the feasibility of the methods to control and bind emphatic motions and adverbial expressions, as well as confirmed contribution of the emphatic motions and positive correlation of adverbial expressions for participants' improvements in motion learning. Based on the results, we introduce a hypothesis that individually optimized method for binding adverbial expression is required.

One-dimensional stable distributions

CERN Document Server

Zolotarev, V M

1986-01-01

This is the first book specifically devoted to a systematic exposition of the essential facts known about the properties of stable distributions. In addition to its main focus on the analytic properties of stable laws, the book also includes examples of the occurrence of stable distributions in applied problems and a chapter on the problem of statistical estimation of the parameters determining stable laws. A valuable feature of the book is the author's use of several formally different ways of expressing characteristic functions corresponding to these laws.

Knee Motion Generation Method for Transfemoral Prosthesis Based on Kinematic Synergy and Inertial Motion.

Science.gov (United States)

Sano, Hiroshi; Wada, Takahiro

2017-12-01

Previous research has shown that the effective use of inertial motion (i.e., less or no torque input at the knee joint) plays an important role in achieving a smooth gait of transfemoral prostheses in the swing phase. In our previous research, a method for generating a timed knee trajectory close to able-bodied individuals, which leads to sufficient clearance between the foot and the floor and the knee extension, was proposed using the inertial motion. Limb motions are known to correlate with each other during walking. This phenomenon is called kinematic synergy. In this paper, we measure gaits in level walking of able-bodied individuals with a wide range of walking velocities. We show that this kinematic synergy also exists between the motions of the intact limbs and those of the knee as determined by the inertial motion technique. We then propose a new method for generating the motion of the knee joint using its inertial motion close to the able-bodied individuals in mid-swing based on its kinematic synergy, such that the method can adapt to the changes in the motion velocity. The numerical simulation results show that the proposed method achieves prosthetic walking similar to that of able-bodied individuals with a wide range of constant walking velocities and termination of walking from steady-state walking. Further investigations have found that a kinematic synergy also exists at the start of walking. Overall, our method successfully achieves knee motion generation from the initiation of walking through steady-state walking with different velocities until termination of walking.

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.

Robust motion estimation using connected operators

OpenAIRE

Salembier Clairon, Philippe Jean; Sanson, H

1997-01-01

This paper discusses the use of connected operators for robust motion estimation The proposed strategy involves a motion estimation step extracting the dominant motion and a ltering step relying on connected operators that remove objects that do not fol low the dominant motion. These two steps are iterated in order to obtain an accurate motion estimation and a precise de nition of the objects fol lowing this motion This strategy can be applied on the entire frame or on individual connected c...

The sarcomeric cytoskeleton: from molecules to motion.

Science.gov (United States)

Gautel, Mathias; Djinović-Carugo, Kristina

2016-01-01

Highly ordered organisation of striated muscle is the prerequisite for the fast and unidirectional development of force and motion during heart and skeletal muscle contraction. A group of proteins, summarised as the sarcomeric cytoskeleton, is essential for the ordered assembly of actin and myosin filaments into sarcomeres, by combining architectural, mechanical and signalling functions. This review discusses recent cell biological, biophysical and structural insight into the regulated assembly of sarcomeric cytoskeleton proteins and their roles in dissipating mechanical forces in order to maintain sarcomere integrity during passive extension and active contraction. α-Actinin crosslinks in the Z-disk show a pivot-and-rod structure that anchors both titin and actin filaments. In contrast, the myosin crosslinks formed by myomesin in the M-band are of a ball-and-spring type and may be crucial in providing stable yet elastic connections during active contractions, especially eccentric exercise. © 2016. Published by The Company of Biologists Ltd.

P1-17: Pseudo-Haptics Using Motion-in-Depth Stimulus and Second-Order Motion Stimulus

Directory of Open Access Journals (Sweden)

Shuichi Sato

2012-10-01

Full Text Available Modification of motion of the computer cursor during the manipulation by the observer evokes illusory haptic sensation (Lecuyer et al., 2004 ACM SIGCHI '04 239–246. This study investigates the pseudo-haptics using motion-in-depth and second-order motion. A stereoscopic display and a PHANTOM were used in the first experiment. A subject was asked to move a visual target at a constant speed in horizontal, vertical, or front-back direction. During the manipulation, the speed was reduced to 50% for 500 msec. The haptic sensation was measured using the magnitude estimation method. The result indicates that perceived haptic sensation from motion-in-depth was about 30% of that from horizontal or vertical motion. A 2D display and the PHANTOM were used in the second experiment. The motion cue was second order—in each frame, dots in a square patch reverses in contrast (i.e., all black dots become white and all white dots become black. The patch was moved in a horizontal direction. The result indicates that perceived haptic sensation from second-order motion was about 90% of that from first-order motion.

Prediction of Motion Induced Image Degradation Using a Markerless Motion Tracker

DEFF Research Database (Denmark)

Olsen, Rasmus Munch; Johannesen, Helle Hjorth; Henriksen, Otto Mølby

In this work a markerless motion tracker, TCL2, is used to predict image quality in 3D T1 weighted MPRAGE MRI brain scans. An experienced radiologist scored the image quality for 172 scans as being usable or not usable, i.e. if a repeated scan was required. Based on five motion parameters......, a classification algorithm was trained and an accuracy for identifying not usable images of 95.9% was obtained with a sensitivity of 91.7% and specificity of 96.3%. This work shows the feasibility of the markerless motion tracker for predicting image quality with a high accuracy....

Remarks on stable and quasi-stable k-strings at large N

International Nuclear Information System (INIS)

Armoni, A.; Shifman, M.

2003-01-01

We discuss k-strings in the large-N Yang-Mills theory and its supersymmetric extension. Whereas the tension of the bona fide (stable) QCD string is expected to depend only on the N-ality of the representation, tensions that depend on specific representation R are often reported in the lattice literature. In particular, adjoint strings are discussed and found in certain simulations. We clarify this issue by systematically exploiting the notion of the quasi-stable strings which becomes well-defined at large N. The quasi-stable strings with representation-dependent tensions decay, but the decay rate (per unit length per unit time) is suppressed as Λ 2 F(N) where F(N) falls off as a function of N. It can be determined on the case-by-case basis. The quasi-stable strings eventually decay into stable strings whose tension indeed depends only on the N-ality. We also briefly review large-N arguments showing why the Casimir formula for the string tension cannot be correct, and present additional arguments in favor of the sine formula. Finally, we comment on the relevance of our estimates to Euclidean lattice measurements

Evolutionary Stable Strategy

Indian Academy of Sciences (India)

Home; Journals; Resonance – Journal of Science Education; Volume 21; Issue 9. Evolutionary Stable Strategy: Application of Nash Equilibrium in Biology. General Article Volume 21 Issue 9 September 2016 pp 803- ... Keywords. Evolutionary game theory, evolutionary stable state, conflict, cooperation, biological games.

Strong Motion Earthquake Data Values of Digitized Strong-Motion Accelerograms, 1933-1994

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — The Strong Motion Earthquake Data Values of Digitized Strong-Motion Accelerograms is a database of over 15,000 digitized and processed accelerograph records from...

Motion in images is essential to cause motion sickness symptoms, but not to increase postural sway

NARCIS (Netherlands)

Lubeck, A.J.A.; Bos, J.E.; Stins, J.F.

2015-01-01

Abstract Objective It is generally assumed that motion in motion images is responsible for increased postural sway as well as for visually induced motion sickness (VIMS). However, this has not yet been tested. To that end, we studied postural sway and VIMS induced by motion and still images. Method

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.

How much motion is too much motion? Determining motion thresholds by sample size for reproducibility in developmental resting-state MRI

Directory of Open Access Journals (Sweden)

Julia Leonard

2017-03-01

Full Text Available A constant problem developmental neuroimagers face is in-scanner head motion. Children move more than adults and this has led to concerns that developmental changes in resting-state connectivity measures may be artefactual. Furthermore, children are challenging to recruit into studies and therefore researchers have tended to take a permissive stance when setting exclusion criteria on head motion. The literature is not clear regarding our central question: How much motion is too much? Here, we systematically examine the effects of multiple motion exclusion criteria at different sample sizes and age ranges in a large openly available developmental cohort (ABIDE; http://preprocessed-connectomes-project.org/abide. We checked 1 the reliability of resting-state functional magnetic resonance imaging (rs-fMRI pairwise connectivity measures across the brain and 2 the accuracy with which we can separate participants with autism spectrum disorder from typically developing controls based on their rs-fMRI scans using machine learning. We find that reliability on average is primarily sensitive to the number of participants considered, but that increasingly permissive motion thresholds lower case-control prediction accuracy for all sample sizes.

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.

Pattern formation, social forces, and diffusion instability in games with success-driven motion

Science.gov (United States)

Helbing, Dirk

2009-02-01

A local agglomeration of cooperators can support the survival or spreading of cooperation, even when cooperation is predicted to die out according to the replicator equation, which is often used in evolutionary game theory to study the spreading and disappearance of strategies. In this paper, it is shown that success-driven motion can trigger such local agglomeration and may, therefore, be used to supplement other mechanisms supporting cooperation, like reputation or punishment. Success-driven motion is formulated here as a function of the game-theoretical payoffs. It can change the outcome and dynamics of spatial games dramatically, in particular as it causes attractive or repulsive interaction forces. These forces act when the spatial distributions of strategies are inhomogeneous. However, even when starting with homogeneous initial conditions, small perturbations can trigger large inhomogeneities by a pattern-formation instability, when certain conditions are fulfilled. Here, these instability conditions are studied for the prisoner’s dilemma and the snowdrift game. Furthermore, it is demonstrated that asymmetrical diffusion can drive social, economic, and biological systems into the unstable regime, if these would be stable without diffusion.

SU-G-JeP1-07: Development of a Programmable Motion Testbed for the Validation of Ultrasound Tracking Algorithms

Energy Technology Data Exchange (ETDEWEB)

Shepard, A; Matrosic, C; Zagzebski, J; Bednarz, B [University of Wisconsin, Madison, WI (United States)

2016-06-15

Purpose: To develop an advanced testbed that combines a 3D motion stage and ultrasound phantom to optimize and validate 2D and 3D tracking algorithms for real-time motion management during radiation therapy. Methods: A Siemens S2000 Ultrasound scanner utilizing a 9L4 transducer was coupled with the Washington University 4D Phantom to simulate patient motion. The transducer was securely fastened to the 3D stage and positioned to image three cylinders of varying contrast in a Gammex 404GS LE phantom. The transducer was placed within a water bath above the phantom in order to maintain sufficient coupling for the entire range of simulated motion. A programmed motion sequence was used to move the transducer during image acquisition and a cine video was acquired for one minute to allow for long sequence tracking. Images were analyzed using a normalized cross-correlation block matching tracking algorithm and compared to the known motion of the transducer relative to the phantom. Results: The setup produced stable ultrasound motion traces consistent with those programmed into the 3D motion stage. The acquired ultrasound images showed minimal artifacts and an image quality that was more than suitable for tracking algorithm verification. Comparisons of a block matching tracking algorithm with the known motion trace for the three features resulted in an average tracking error of 0.59 mm. Conclusion: The high accuracy and programmability of the 4D phantom allows for the acquisition of ultrasound motion sequences that are highly customizable; allowing for focused analysis of some common pitfalls of tracking algorithms such as partial feature occlusion or feature disappearance, among others. The design can easily be modified to adapt to any probe such that the process can be extended to 3D acquisition. Further development of an anatomy specific phantom better resembling true anatomical landmarks could lead to an even more robust validation. This work is partially funded by NIH

SU-G-JeP1-07: Development of a Programmable Motion Testbed for the Validation of Ultrasound Tracking Algorithms

International Nuclear Information System (INIS)

Shepard, A; Matrosic, C; Zagzebski, J; Bednarz, B

2016-01-01

Purpose: To develop an advanced testbed that combines a 3D motion stage and ultrasound phantom to optimize and validate 2D and 3D tracking algorithms for real-time motion management during radiation therapy. Methods: A Siemens S2000 Ultrasound scanner utilizing a 9L4 transducer was coupled with the Washington University 4D Phantom to simulate patient motion. The transducer was securely fastened to the 3D stage and positioned to image three cylinders of varying contrast in a Gammex 404GS LE phantom. The transducer was placed within a water bath above the phantom in order to maintain sufficient coupling for the entire range of simulated motion. A programmed motion sequence was used to move the transducer during image acquisition and a cine video was acquired for one minute to allow for long sequence tracking. Images were analyzed using a normalized cross-correlation block matching tracking algorithm and compared to the known motion of the transducer relative to the phantom. Results: The setup produced stable ultrasound motion traces consistent with those programmed into the 3D motion stage. The acquired ultrasound images showed minimal artifacts and an image quality that was more than suitable for tracking algorithm verification. Comparisons of a block matching tracking algorithm with the known motion trace for the three features resulted in an average tracking error of 0.59 mm. Conclusion: The high accuracy and programmability of the 4D phantom allows for the acquisition of ultrasound motion sequences that are highly customizable; allowing for focused analysis of some common pitfalls of tracking algorithms such as partial feature occlusion or feature disappearance, among others. The design can easily be modified to adapt to any probe such that the process can be extended to 3D acquisition. Further development of an anatomy specific phantom better resembling true anatomical landmarks could lead to an even more robust validation. This work is partially funded by NIH

Helicopter flight simulation motion platform requirements

Science.gov (United States)

Schroeder, Jeffery Allyn

Flight simulators attempt to reproduce in-flight pilot-vehicle behavior on the ground. This reproduction is challenging for helicopter simulators, as the pilot is often inextricably dependent on external cues for pilot-vehicle stabilization. One important simulator cue is platform motion; however, its required fidelity is unknown. To determine the required motion fidelity, several unique experiments were performed. A large displacement motion platform was used that allowed pilots to fly tasks with matched motion and visual cues. Then, the platform motion was modified to give cues varying from full motion to no motion. Several key results were found. First, lateral and vertical translational platform cues had significant effects on fidelity. Their presence improved performance and reduced pilot workload. Second, yaw and roll rotational platform cues were not as important as the translational platform cues. In particular, the yaw rotational motion platform cue did not appear at all useful in improving performance or reducing workload. Third, when the lateral translational platform cue was combined with visual yaw rotational cues, pilots believed the platform was rotating when it was not. Thus, simulator systems can be made more efficient by proper combination of platform and visual cues. Fourth, motion fidelity specifications were revised that now provide simulator users with a better prediction of motion fidelity based upon the frequency responses of their motion control laws. Fifth, vertical platform motion affected pilot estimates of steady-state altitude during altitude repositionings. This refutes the view that pilots estimate altitude and altitude rate in simulation solely from visual cues. Finally, the combined results led to a general method for configuring helicopter motion systems and for developing simulator tasks that more likely represent actual flight. The overall results can serve as a guide to future simulator designers and to today's operators.

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.

Projectile Motion Hoop Challenge

Science.gov (United States)

Jordan, Connor; Dunn, Amy; Armstrong, Zachary; Adams, Wendy K.

2018-04-01

Projectile motion is a common phenomenon that is used in introductory physics courses to help students understand motion in two dimensions. Authors have shared a range of ideas for teaching this concept and the associated kinematics in The Physics Teacher; however, the "Hoop Challenge" is a new setup not before described in TPT. In this article an experiment is illustrated to explore projectile motion in a fun and challenging manner that has been used with both high school and university students. With a few simple materials, students have a vested interest in being able to calculate the height of the projectile at a given distance from its launch site. They also have an exciting visual demonstration of projectile motion when the lab is over.

WE-G-18C-06: Is Diaphragm Motion a Good Surrogate for Liver Tumor Motion?

Energy Technology Data Exchange (ETDEWEB)

Yang, J [Department of Radiation Oncology, Duke University Medical Center, Durham, NC (United States); School of Information Science and Engineering, Shandong University, Jinan, Shandong (China); Cai, J; Zheng, C; Czito, B; Palta, M; Yin, F [Department of Radiation Oncology, Duke University Medical Center, Durham, NC (United States); Wang, H [School of Information Science and Engineering, Shandong University, Jinan, Shandong (China); Bashir, M [Department of Radiology, Duke University Medical Center, Durham, NC (United States)

2014-06-15

Purpose: To investigate whether diaphragm motion is a good surrogate for liver tumor motion by comparing their motion trajectories obtained from cine-MRI. Methods: Fourteen patients with hepatocellular carcinoma (10/14) or liver metastases (4/14) undergoing radiation therapy were included in this study. All patients underwent single-slice 2D cine-MRI simulations across the center of the tumor in three orthogonal planes. Tumor and diaphragm motion trajectories in the superior-inferior (SI), anteriorposterior (AP), and medial-lateral (ML) directions were obtained using the normalized cross-correlation based tracking technique. Agreement between tumor and diaphragm motions was assessed by calculating the phase difference percentage (PDP), intra-class correlation coefficient (ICC), Bland-Altman analysis (Diffs) and paired t-test. The distance (D) between tumor and tracked diaphragm area was analyzed to understand its impact on the correlation between tumor and diaphragm motions. Results: Of all patients, the means (±standard deviations) of PDP were 7.1 (±1.1)%, 4.5 (±0.5)% and 17.5 (±4.5)% in the SI, AP and ML directions, respectively. The means of ICC were 0.98 (±0.02), 0.97 (±0.02), and 0.08 (±0.06) in the SI, AP and ML directions, respectively. The Diffs were 2.8 (±1.4) mm, 2.4 (±1.1) mm, and 2.2 (±0.5) mm in the SI, AP and ML directions, respectively. The p-values derived from the paired t-test were < 0.02 in SI and AP directions, whereas were > 0.58 in ML direction primarily due to the small motion in ML direction. Tumor and diaphragmatic motion had high concordance when the distance between the tumor and tracked diaphragm areas was small. Conclusion: Preliminary results showed that liver tumor motion had good correlations with diaphragm motion in the SI and AP directions, indicating diaphragm motion in the SI and AP directions could potentially be a reliable surrogate for liver tumor motion. NIH (1R21CA165384-01A1), Golfers Against Cancer (GAC

Haptically Induced Illusory Self-motion and the Influence of Context of Motion

DEFF Research Database (Denmark)

Nilsson, Niels Christian; Nordahl, Rolf; Sikström, Erik

2012-01-01

of the feet. The experiment was based on the a within-subjects design and included four conditions, each representing one context of motion: an elevator, a train compartment, a bathroom, and a completely dark environment. The audiohaptic stimuli was identical across all conditions. The participants’ sensation...... of movement was assessed by means of existing measures of illusory self-motion, namely, reported self-motion illusion per stimulus type, illusion compellingness, intensity and onset time. Finally the participants were also asked to estimate the experienced direction of movement. While the data obtained from...

Motion sickness symptoms in a ship motion simulator: effects of inside, outside, and no view

NARCIS (Netherlands)

Bos, J.E.; MacKinnon, S.N.; Patterson, A.

2005-01-01

Vehicle motion characteristics differ between air, road, and sea environments, both vestibularly and visually. Effects of vision on motion sickness have been studied before, though less systematically in a naval setting. It is hypothesized that appropriate visual information on self-motion is

Motion adaptation leads to parsimonious encoding of natural optic flow by blowfly motion vision system

NARCIS (Netherlands)

Heitwerth, J.; Kern, R.; Hateren, J.H. van; Egelhaaf, M.

Neurons sensitive to visual motion change their response properties during prolonged motion stimulation. These changes have been interpreted as adaptive and were concluded, for instance, to adjust the sensitivity of the visual motion pathway to velocity changes or to increase the reliability of

A Simple and High Performing Rate Control Initialization Method for H.264 AVC Coding Based on Motion Vector Map and Spatial Complexity at Low Bitrate

Directory of Open Access Journals (Sweden)

Yalin Wu

2014-01-01

Full Text Available The temporal complexity of video sequences can be characterized by motion vector map which consists of motion vectors of each macroblock (MB. In order to obtain the optimal initial QP (quantization parameter for the various video sequences which have different spatial and temporal complexities, this paper proposes a simple and high performance initial QP determining method based on motion vector map and temporal complexity to decide an initial QP in given target bit rate. The proposed algorithm produces the reconstructed video sequences with outstanding and stable quality. For any video sequences, the initial QP can be easily determined from matrices by target bit rate and mapped spatial complexity using proposed mapping method. Experimental results show that the proposed algorithm can show more outstanding objective and subjective performance than other conventional determining methods.

19 CFR 210.15 - Motions.

Science.gov (United States)

2010-04-01

... 19 Customs Duties 3 2010-04-01 2010-04-01 false Motions. 210.15 Section 210.15 Customs Duties UNITED STATES INTERNATIONAL TRADE COMMISSION INVESTIGATIONS OF UNFAIR PRACTICES IN IMPORT TRADE ADJUDICATION AND ENFORCEMENT Motions § 210.15 Motions. (a) Presentation and disposition. (1) During the period...

A motion algorithm to extract physical and motion parameters of mobile targets from cone-beam computed tomographic images.

Science.gov (United States)

Alsbou, Nesreen; Ahmad, Salahuddin; Ali, Imad

2016-05-17

A motion algorithm has been developed to extract length, CT number level and motion amplitude of a mobile target from cone-beam CT (CBCT) images. The algorithm uses three measurable parameters: Apparent length and blurred CT number distribution of a mobile target obtained from CBCT images to determine length, CT-number value of the stationary target, and motion amplitude. The predictions of this algorithm are tested with mobile targets having different well-known sizes that are made from tissue-equivalent gel which is inserted into a thorax phantom. The phantom moves sinusoidally in one-direction to simulate respiratory motion using eight amplitudes ranging 0-20 mm. Using this motion algorithm, three unknown parameters are extracted that include: Length of the target, CT number level, speed or motion amplitude for the mobile targets from CBCT images. The motion algorithm solves for the three unknown parameters using measured length, CT number level and gradient for a well-defined mobile target obtained from CBCT images. The motion model agrees with the measured lengths which are dependent on the target length and motion amplitude. The gradient of the CT number distribution of the mobile target is dependent on the stationary CT number level, the target length and motion amplitude. Motion frequency and phase do not affect the elongation and CT number distribution of the mobile target and could not be determined. A motion algorithm has been developed to extract three parameters that include length, CT number level and motion amplitude or speed of mobile targets directly from reconstructed CBCT images without prior knowledge of the stationary target parameters. This algorithm provides alternative to 4D-CBCT without requirement of motion tracking and sorting of the images into different breathing phases. The motion model developed here works well for tumors that have simple shapes, high contrast relative to surrounding tissues and move nearly in regular motion pattern

STABLE CONIC-HELICAL ORBITS OF PLANETS AROUND BINARY STARS: ANALYTICAL RESULTS

Energy Technology Data Exchange (ETDEWEB)

Oks, E. [Physics Department, 206 Allison Lab., Auburn University, Auburn, AL 36849 (United States)

2015-05-10

Studies of planets in binary star systems are especially important because it was estimated that about half of binary stars are capable of supporting habitable terrestrial planets within stable orbital ranges. One-planet binary star systems (OBSS) have a limited analogy to objects studied in atomic/molecular physics: one-electron Rydberg quasimolecules (ORQ). Specifically, ORQ, consisting of two fully stripped ions of the nuclear charges Z and Z′ plus one highly excited electron, are encountered in various plasmas containing more than one kind of ion. Classical analytical studies of ORQ resulted in the discovery of classical stable electronic orbits with the shape of a helix on the surface of a cone. In the present paper we show that despite several important distinctions between OBSS and ORQ, it is possible for OBSS to have stable planetary orbits in the shape of a helix on a conical surface, whose axis of symmetry coincides with the interstellar axis; the stability is not affected by the rotation of the stars. Further, we demonstrate that the eccentricity of the stars’ orbits does not affect the stability of the helical planetary motion if the center of symmetry of the helix is relatively close to the star of the larger mass. We also show that if the center of symmetry of the conic-helical planetary orbit is relatively close to the star of the smaller mass, a sufficiently large eccentricity of stars’ orbits can switch the planetary motion to the unstable mode and the planet would escape the system. We demonstrate that such planets are transitable for the overwhelming majority of inclinations of plane of the stars’ orbits (i.e., the projections of the planet and the adjacent start on the plane of the sky coincide once in a while). This means that conic-helical planetary orbits at binary stars can be detected photometrically. We consider, as an example, Kepler-16 binary stars to provide illustrative numerical data on the possible parameters and the

Motion-compensated processing of image signals

NARCIS (Netherlands)

2010-01-01

In a motion-compensated processing of images, input images are down-scaled (scl) to obtain down-scaled images, the down-scaled images are subjected to motion- compensated processing (ME UPC) to obtain motion-compensated images, the motion- compensated images are up-scaled (sc2) to obtain up-scaled

19 CFR 210.26 - Other motions.

Science.gov (United States)

2010-04-01

... 19 Customs Duties 3 2010-04-01 2010-04-01 false Other motions. 210.26 Section 210.26 Customs Duties UNITED STATES INTERNATIONAL TRADE COMMISSION INVESTIGATIONS OF UNFAIR PRACTICES IN IMPORT TRADE ADJUDICATION AND ENFORCEMENT Motions § 210.26 Other motions. Motions pertaining to discovery shall be filed in...

A PSF-Shape-Based Beamforming Strategy for Robust 2D Motion Estimation in Ultrafast Data

Directory of Open Access Journals (Sweden)

Anne E. C. M. Saris

2018-03-01

Full Text Available This paper presents a framework for motion estimation in ultrafast ultrasound data. It describes a novel approach for determining the sampling grid for ultrafast data based on the system’s point-spread-function (PSF. As a consequence, the cross-correlation functions (CCF used in the speckle tracking (ST algorithm will have circular-shaped peaks, which can be interpolated using a 2D interpolation method to estimate subsample displacements. Carotid artery wall motion and parabolic blood flow simulations together with rotating disk experiments using a Verasonics Vantage 256 are used for performance evaluation. Zero-degree plane wave data were acquired using an ATL L5-12 (fc = 9 MHz transducer for a range of pulse repetition frequencies (PRFs, resulting in 0–600 µm inter-frame displacements. The proposed methodology was compared to data beamformed on a conventionally spaced grid, combined with the commonly used 1D parabolic interpolation. The PSF-shape-based beamforming grid combined with 2D cubic interpolation showed the most accurate and stable performance with respect to the full range of inter-frame displacements, both for the assessment of blood flow and vessel wall dynamics. The proposed methodology can be used as a protocolled way to beamform ultrafast data and obtain accurate estimates of tissue motion.

Model-Based Design of Brushless DC Motor Control and Motion Control Modelling for RoboCup SSL Robots

OpenAIRE

Li, Xiaotian

2015-01-01

Over the recent years, the RoboCup competition has grown popular and attracted more and more domestic and international universities, and the levels of the teams increase every year. In Small Size League (SSL) competition, besides a good strategy system, the precision of the robots’ actions is also of vital importance in order to achieve high performance. Thus, a highly accurate and stable motion control system is needed to drive the robots to move in accordance with the planned trajectory. C...

Angular stable plates in proximal meta-epiphyseal tibial fractures: study of joint restoration and clinical and functional evaluation.

Science.gov (United States)

Giannotti, S; Giovannelli, D; Dell'Osso, G; Bottai, V; Bugelli, G; Celli, F; Citarelli, C; Guido, G

2016-04-01

The tibial plateau fractures involve one of the main weight bearing joints of the human body. The goals of surgical treatment are anatomical reduction, articular surface reconstruction and high primary stability. The aim of this study was to evaluate the clinical and functional outcomes after internal plate fixation of this kind of fractures. From January 2009 to December 2012, we treated 75 cases of tibial plateau fracture with angular stable plates. We used Rasmussen Score and the Knee Society Score for the clinical and functional evaluation. Twenty-five cases that underwent hardware removal had arthroscopic and CT evaluation of the joint. No complications occurred. The clinical and functional evaluation, performed by the KSS and Rasmussen Score, highlighted the high percentage of good-to-excellent results (over 90 %). In every case, the range of motion was good with flexion >90°. Arthroscopy showed the presence of chondral damage in 100 % of patients. In all the cases, we found that X-ray images seem better than the CT images. Angular stable plates allow to obtain a good primary stability, permitting an early joint recovery with an excellent range of motion. Avoiding to perform a knee arthrotomy at the time of fracture reduction could prove to be an advantage in terms of functional recovery. The meniscus on the injured bone should be preserved in order to maintain good function of the joint. X-ray images remain the gold standard in checking the progression of post-traumatic osteoarthritis.

Time-Dependent Selection of an Optimal Set of Sources to Define a Stable Celestial Reference Frame

Science.gov (United States)

Le Bail, Karine; Gordon, David

2010-01-01

Temporal statistical position stability is required for VLBI sources to define a stable Celestial Reference Frame (CRF) and has been studied in many recent papers. This study analyzes the sources from the latest realization of the International Celestial Reference Frame (ICRF2) with the Allan variance, in addition to taking into account the apparent linear motions of the sources. Focusing on the 295 defining sources shows how they are a good compromise of different criteria, such as statistical stability and sky distribution, as well as having a sufficient number of sources, despite the fact that the most stable sources of the entire ICRF2 are mostly in the Northern Hemisphere. Nevertheless, the selection of a stable set is not unique: studying different solutions (GSF005a and AUG24 from GSFC and OPA from the Paris Observatory) over different time periods (1989.5 to 2009.5 and 1999.5 to 2009.5) leads to selections that can differ in up to 20% of the sources. Observing, recording, and network improvement are some of the causes, showing better stability for the CRF over the last decade than the last twenty years. But this may also be explained by the assumption of stationarity that is not necessarily right for some sources.

Simulated earthquake ground motions

International Nuclear Information System (INIS)

Vanmarcke, E.H.; Gasparini, D.A.

1977-01-01

The paper reviews current methods for generating synthetic earthquake ground motions. Emphasis is on the special requirements demanded of procedures to generate motions for use in nuclear power plant seismic response analysis. Specifically, very close agreement is usually sought between the response spectra of the simulated motions and prescribed, smooth design response spectra. The features and capabilities of the computer program SIMQKE, which has been widely used in power plant seismic work are described. Problems and pitfalls associated with the use of synthetic ground motions in seismic safety assessment are also pointed out. The limitations and paucity of recorded accelerograms together with the widespread use of time-history dynamic analysis for obtaining structural and secondary systems' response have motivated the development of earthquake simulation capabilities. A common model for synthesizing earthquakes is that of superposing sinusoidal components with random phase angles. The input parameters for such a model are, then, the amplitudes and phase angles of the contributing sinusoids as well as the characteristics of the variation of motion intensity with time, especially the duration of the motion. The amplitudes are determined from estimates of the Fourier spectrum or the spectral density function of the ground motion. These amplitudes may be assumed to be varying in time or constant for the duration of the earthquake. In the nuclear industry, the common procedure is to specify a set of smooth response spectra for use in aseismic design. This development and the need for time histories have generated much practical interest in synthesizing earthquakes whose response spectra 'match', or are compatible with a set of specified smooth response spectra

Usefulness of 123I-BMIPP myocardial imaging in patients with stable effort angina and unstable angina

International Nuclear Information System (INIS)

Inoue, Seiji; Kobayashi, Hideki; Oka, Toshiaki; Kawaguchi, Masao; Momose, Mitsuru; Kasanuki, Hiroshi; Kusakabe, Kiyoko; Hosoda, Saichi

1995-01-01

We evaluated the clinical significance of myocardial imaging using 123 I-15-(p-iodophenyl)-3-methyl pentadecanoic acid (BMIPP) scintigraphy in patients with stable effort angina pectoris (SAP) and unstable angina pectoris (UAP). Thirty-three patients with SAP were studied using rest BMIPP and stress 201 TlCl (Tl) myocardial scintigraphy, and 13 patients with worsening effort type of UAP were also examined using both rest BMIPP and Tl scintigraphy. We compared those BMIPP findings with myocardial perfusion images obtained with Tl and the regional wall motion determined by left ventriculography. In 45% of 282 segments of myocardial ischemia of SAP, the degree of myocardial uptake of BMIPP was concordant with that of stress Tl and the defect score of Tl was higher than that of BMIPP. On the other hand, in 32% of 62 segments of ischemia of UAP, the degree of myocardial BMIPP and Tl uptake was concordant and BMIPP defect score was higher than Tl score. In SAP, the decrease in regional wall motion agreed better with the decrease in myocardial uptake of BMIPP than that of Tl. These results suggest that myocardial ischemic regions decreased BMIPP uptake show the disturbance of fatty acid metabolism and lead to abnormal wall motions. Such ischemic regions may be clinically severe state in patients with angina pectoris. (author)

Trajectory of coronary motion and its significance in robotic motion cancellation.

Science.gov (United States)

Cattin, Philippe; Dave, Hitendu; Grünenfelder, Jürg; Szekely, Gabor; Turina, Marko; Zünd, Gregor

2004-05-01

To characterize remaining coronary artery motion of beating pig hearts after stabilization with an 'Octopus' using an optical remote analysis technique. Three pigs (40, 60 and 65 kg) underwent full sternotomy after receiving general anesthesia. An 8-bit high speed black and white video camera (50 frames/s) coupled with a laser sensor (60 microm resolution) were used to capture heart wall motion in all three dimensions. Dopamine infusion was used to deliberately modulate cardiac contractility. Synchronized ECG, blood pressure, airway pressure and video data of the region around the first branching point of the left anterior descending (LAD) coronary artery after Octopus stabilization were captured for stretches of 8 s each. Several sequences of the same region were captured over a period of several minutes. Computerized off-line analysis allowed us to perform minute characterization of the heart wall motion. The movement of the points of interest on the LAD ranged from 0.22 to 0.81 mm in the lateral plane (x/y-axis) and 0.5-2.6 mm out of the plane (z-axis). Fast excursions (>50 microm/s in the lateral plane) occurred corresponding to the QRS complex and the T wave; while slow excursion phases (movement of the coronary artery after stabilization appears to be still significant. Minute characterization of the trajectory of motion could provide the substrate for achieving motion cancellation for existing robotic systems. Velocity plots could also help improve gated cardiac imaging.

Stable Boundary Layer Issues

OpenAIRE

Steeneveld, G.J.

2012-01-01

Understanding and prediction of the stable atmospheric boundary layer is a challenging task. Many physical processes are relevant in the stable boundary layer, i.e. turbulence, radiation, land surface coupling, orographic turbulent and gravity wave drag, and land surface heterogeneity. The development of robust stable boundary layer parameterizations for use in NWP and climate models is hampered by the multiplicity of processes and their unknown interactions. As a result, these models suffer ...

Modeling repetitive motions using structured light.

Science.gov (United States)

Xu, Yi; Aliaga, Daniel G

2010-01-01

Obtaining models of dynamic 3D objects is an important part of content generation for computer graphics. Numerous methods have been extended from static scenarios to model dynamic scenes. If the states or poses of the dynamic object repeat often during a sequence (but not necessarily periodically), we call such a repetitive motion. There are many objects, such as toys, machines, and humans, undergoing repetitive motions. Our key observation is that when a motion-state repeats, we can sample the scene under the same motion state again but using a different set of parameters; thus, providing more information of each motion state. This enables robustly acquiring dense 3D information difficult for objects with repetitive motions using only simple hardware. After the motion sequence, we group temporally disjoint observations of the same motion state together and produce a smooth space-time reconstruction of the scene. Effectively, the dynamic scene modeling problem is converted to a series of static scene reconstructions, which are easier to tackle. The varying sampling parameters can be, for example, structured-light patterns, illumination directions, and viewpoints resulting in different modeling techniques. Based on this observation, we present an image-based motion-state framework and demonstrate our paradigm using either a synchronized or an unsynchronized structured-light acquisition method.

Ground motion input in seismic evaluation studies

International Nuclear Information System (INIS)

Sewell, R.T.; Wu, S.C.

1996-07-01

This report documents research pertaining to conservatism and variability in seismic risk estimates. Specifically, it examines whether or not artificial motions produce unrealistic evaluation demands, i.e., demands significantly inconsistent with those expected from real earthquake motions. To study these issues, two types of artificial motions are considered: (a) motions with smooth response spectra, and (b) motions with realistic variations in spectral amplitude across vibration frequency. For both types of artificial motion, time histories are generated to match target spectral shapes. For comparison, empirical motions representative of those that might result from strong earthquakes in the Eastern U.S. are also considered. The study findings suggest that artificial motions resulting from typical simulation approaches (aimed at matching a given target spectrum) are generally adequate and appropriate in representing the peak-response demands that may be induced in linear structures and equipment responding to real earthquake motions. Also, given similar input Fourier energies at high-frequencies, levels of input Fourier energy at low frequencies observed for artificial motions are substantially similar to those levels noted in real earthquake motions. In addition, the study reveals specific problems resulting from the application of Western U.S. type motions for seismic evaluation of Eastern U.S. nuclear power plants

Motion correction in neurological fan beam SPECT using motion tracking and fully 3D reconstruction

International Nuclear Information System (INIS)

Fulton, R.R.; Hutton, B.; Eberl, S.; Meikle, S.; Braun, M.; Westmead Hospital, Westmead, NSW; University of Technology, Sydney, NSW

1998-01-01

Full text: We have previously proposed the use of fully three-dimensional (3D) reconstruction and continuous monitoring of head position to correct for motion artifacts in neurological SPECT and PET. Knowledge of the motion during acquisition provided by a head tracking system can be used to reposition the projection data in space in such a way as to negate motion effects during reconstruction. The reconstruction algorithm must deal with variations in the projection geometry resulting from differences in the timing and nature of motion between patients. Rotational movements about any axis other than the camera's axis of rotation give rise to projection geometries which necessitate the use of a fully 3D reconstruction algorithm. Our previous work with computer simulations assuming parallel hole collimation demonstrated the feasibility of correcting for motion. We have now refined our iterative 3D reconstruction algorithm to support fan beam data and attenuation correction, and developed a practical head tracking system for use on a Trionix Triad SPECT system. The correction technique has been tested in fan beam SPECT studies of the 3D Hoffman brain phantom. Arbitrary movements were applied to the phantom during acquisition and recorded by the head tracker which monitored the position and orientation of the phantom throughout the study. 3D reconstruction was then performed using the motion data provided by the tracker. The accuracy of correction was assessed by comparing the corrected images with a motion free study acquired immediately beforehand, visually and by calculating mean squared error (MSE). Motion correction reduced distortion perceptibly and, depending on the motions applied, improved MSE by up to an order of magnitude. 3D reconstruction of the 128x128x128 data set took 20 minutes on a SUN Ultra 1 workstation. The results of these phantom experiments suggest that the technique can effectively compensate for head motion under clinical SPECT imaging

Fractional Brownian motion and motion governed by the fractional Langevin equation in confined geometries.

Science.gov (United States)

Jeon, Jae-Hyung; Metzler, Ralf

2010-02-01

Motivated by subdiffusive motion of biomolecules observed in living cells, we study the stochastic properties of a non-Brownian particle whose motion is governed by either fractional Brownian motion or the fractional Langevin equation and restricted to a finite domain. We investigate by analytic calculations and simulations how time-averaged observables (e.g., the time-averaged mean-squared displacement and displacement correlation) are affected by spatial confinement and dimensionality. In particular, we study the degree of weak ergodicity breaking and scatter between different single trajectories for this confined motion in the subdiffusive domain. The general trend is that deviations from ergodicity are decreased with decreasing size of the movement volume and with increasing dimensionality. We define the displacement correlation function and find that this quantity shows distinct features for fractional Brownian motion, fractional Langevin equation, and continuous time subdiffusion, such that it appears an efficient measure to distinguish these different processes based on single-particle trajectory data.

Wall-crossing between stable and co-stable ADHM data

Science.gov (United States)

Ohkawa, Ryo

2018-06-01

We prove formula between Nekrasov partition functions defined from stable and co-stable ADHM data for the plane following method by Nakajima and Yoshioka (Kyoto J Math 51(2):263-335, 2011) based on the theory of wall-crossing formula developed by Mochizuki (Donaldson type invariants for algebraic surfaces: transition of moduli stacks, Lecture notes in mathematics, vol 1972, Springer, Berlin, 2009). This formula is similar to conjectures by Ito et al. [J High Energy Phys 2013(5):045, 2013, (4.1), (4.2)] for A1 singularity.

Motion Learning Based on Bayesian Program Learning

Directory of Open Access Journals (Sweden)

Cheng Meng-Zhen

2017-01-01

Full Text Available The concept of virtual human has been highly anticipated since the 1980s. By using computer technology, Human motion simulation could generate authentic visual effect, which could cheat human eyes visually. Bayesian Program Learning train one or few motion data, generate new motion data by decomposing and combining. And the generated motion will be more realistic and natural than the traditional one.In this paper, Motion learning based on Bayesian program learning allows us to quickly generate new motion data, reduce workload, improve work efficiency, reduce the cost of motion capture, and improve the reusability of data.

Simultaneous PET-MR acquisition and MR-derived motion fields for correction of non-rigid motion in PET

International Nuclear Information System (INIS)

Tsoumpas, C.; Mackewn, J.E.; Halsted, P.; King, A.P.; Buerger, C.; Totman, J.J.; Schaeffter, T.; Marsden, P.K.

2010-01-01

Positron emission tomography (PET) provides an accurate measurement of radiotracer concentration in vivo, but performance can be limited by subject motion which degrades spatial resolution and quantitative accuracy. This effect may become a limiting factor for PET studies in the body as PET scanner technology improves. In this work, we propose a new approach to address this problem by employing motion information from images measured simultaneously using a magnetic resonance (MR) scanner. The approach is demonstrated using an MR-compatible PET scanner and PET-MR acquisition with a purpose-designed phantom capable of non-rigid deformations. Measured, simultaneously acquired MR data were used to correct for motion in PET, and results were compared with those obtained using motion information from PET images alone. Motion artefacts were significantly reduced and the PET image quality and quantification was significantly improved by the use of MR motion fields, whilst the use of PET-only motion information was less successful. Combined PET-MR acquisitions potentially allow PET motion compensation in whole-body acquisitions without prolonging PET acquisition time or increasing radiation dose. This, to the best of our knowledge, is the first study to demonstrate that simultaneously acquired MR data can be used to estimate and correct for the effects of non-rigid motion in PET. (author)

COMPARISON OF BACKGROUND SUBTRACTION, SOBEL, ADAPTIVE MOTION DETECTION, FRAME DIFFERENCES, AND ACCUMULATIVE DIFFERENCES IMAGES ON MOTION DETECTION

Directory of Open Access Journals (Sweden)

Dara Incam Ramadhan

2018-02-01

Full Text Available Nowadays, digital image processing is not only used to recognize motionless objects, but also used to recognize motions objects on video. One use of moving object recognition on video is to detect motion, which implementation can be used on security cameras. Various methods used to detect motion have been developed so that in this research compared some motion detection methods, namely Background Substraction, Adaptive Motion Detection, Sobel, Frame Differences and Accumulative Differences Images (ADI. Each method has a different level of accuracy. In the background substraction method, the result obtained 86.1% accuracy in the room and 88.3% outdoors. In the sobel method the result of motion detection depends on the lighting conditions of the room being supervised. When the room is in bright condition, the accuracy of the system decreases and when the room is dark, the accuracy of the system increases with an accuracy of 80%. In the adaptive motion detection method, motion can be detected with a condition in camera visibility there is no object that is easy to move. In the frame difference method, testing on RBG image using average computation with threshold of 35 gives the best value. In the ADI method, the result of accuracy in motion detection reached 95.12%.

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.

Simulation of multibunch motion with the Headtail code and application to the CERN SPS and LHC

CERN Document Server

Mounet, N; Rumolo, G

2011-01-01

Multibunch instabilities due to beam-coupling impedance can be a critical limitation for synchrotrons operating with many bunches. It is particularly true for the LHC under nominal conditions, where according to theoretical predictions the 2808 bunches rely entirely on the performance of the transverse feedback system to remain stable. To study these instabilities, the HEADTAIL code has been extended to simulate the motion of many bunches under the action of wake fields. All the features already present in the single-bunch version of the code, such as synchrotron motion, chromaticity, amplitude detuning due to octupoles and the ability to load any kind of wake fields through tables, have remained available. This new code has been then parallelized in order to track thousands of bunches in a reasonable amount of time. The code was benchmarked against theory and exhibited a good agreement. We also show results for bunch trains in the LHC and compare them with beam-based measurements.

The colour of thermal noise in classical Brownian motion: a feasibility study of direct experimental observation

International Nuclear Information System (INIS)

Berg-Soerensen, Kirstine; Flyvbjerg, Henrik

2005-01-01

One hundred years after Einstein modelled Brownian motion, a central aspect of this motion in incompressible fluids has not been verified experimentally: the thermal noise that drives the Brownian particle, is not white, as in Einstein's simple theory. It is slightly coloured, due to hydrodynamics and the fluctuation-dissipation theorem. This theoretical result from the 1970s was prompted by computer simulation results in apparent violation of Einstein's theory. We discuss how a direct experimental observation of this colour might be carried out by using optical tweezers to separate the thermal noise from the particle's dynamic response to it. Since the thermal noise is almost white, very good statistics is necessary to resolve its colour. That requires stable equipment and long recording times, possibly making this experiment one for the future only. We give results for experimental requirements and for stochastic errors as functions of experimental window and measurement time, and discuss some potential sources of systematic errors

Performance assessment of a programmable five degrees-of-freedom motion platform for quality assurance of motion management techniques in radiotherapy.

Science.gov (United States)

Huang, Chen-Yu; Keall, Paul; Rice, Adam; Colvill, Emma; Ng, Jin Aun; Booth, Jeremy T

2017-09-01

Inter-fraction and intra-fraction motion management methods are increasingly applied clinically and require the development of advanced motion platforms to facilitate testing and quality assurance program development. The aim of this study was to assess the performance of a 5 degrees-of-freedom (DoF) programmable motion platform HexaMotion (ScandiDos, Uppsala, Sweden) towards clinically observed tumor motion range, velocity, acceleration and the accuracy requirements of SABR prescribed in AAPM Task Group 142. Performance specifications for the motion platform were derived from literature regarding the motion characteristics of prostate and lung tumor targets required for real time motion management. The performance of the programmable motion platform was evaluated against (1) maximum range, velocity and acceleration (5 DoF), (2) static position accuracy (5 DoF) and (3) dynamic position accuracy using patient-derived prostate and lung tumor motion traces (3 DoF). Translational motion accuracy was compared against electromagnetic transponder measurements. Rotation was benchmarked with a digital inclinometer. The static accuracy and reproducibility for translation and rotation was quality assurance and commissioning of motion management systems in radiation oncology.

Angina Pectoris (Stable Angina)

Science.gov (United States)

... Peripheral Artery Disease Venous Thromboembolism Aortic Aneurysm More Angina Pectoris (Stable Angina) Updated:Aug 21,2017 You may have heard the term “angina pectoris” or “stable angina” in your doctor’s office, ...

Characteristics of near-field earthquake ground motion

International Nuclear Information System (INIS)

Kim, H. K.; Choi, I. G.; Jeon, Y. S.; Seo, J. M.

2002-01-01

The near-field ground motions exhibit special response characteristics that are different from those of ordinary ground motions in the velocity and displacement response. This study first examines the characteristics of near-field ground motion depending on fault directivity and fault normal and parallel component. And the response spectra of the near field ground motion are statistically processed, and are compared with the Regulatory Guide 1.60 spectrum that is present design spectrum of the nuclear power plant. The response spectrum of the near filed ground motions shows large spectral velocity and displacement in the low frequency range. The spectral accelerations of near field ground motion are greatly amplified in the high frequency range for the rock site motions, and in the low frequency range for the soil site motions. As a result, the near field ground motion effects should be considered in the seismic design and seismic safety evaluation of the nuclear power plant structures and equipment

Human motion retrieval from hand-drawn sketch.

Science.gov (United States)

Chao, Min-Wen; Lin, Chao-Hung; Assa, Jackie; Lee, Tong-Yee

2012-05-01

The rapid growth of motion capture data increases the importance of motion retrieval. The majority of the existing motion retrieval approaches are based on a labor-intensive step in which the user browses and selects a desired query motion clip from the large motion clip database. In this work, a novel sketching interface for defining the query is presented. This simple approach allows users to define the required motion by sketching several motion strokes over a drawn character, which requires less effort and extends the users’ expressiveness. To support the real-time interface, a specialized encoding of the motions and the hand-drawn query is required. Here, we introduce a novel hierarchical encoding scheme based on a set of orthonormal spherical harmonic (SH) basis functions, which provides a compact representation, and avoids the CPU/processing intensive stage of temporal alignment used by previous solutions. Experimental results show that the proposed approach can well retrieve the motions, and is capable of retrieve logically and numerically similar motions, which is superior to previous approaches. The user study shows that the proposed system can be a useful tool to input motion query if the users are familiar with it. Finally, an application of generating a 3D animation from a hand-drawn comics strip is demonstrated.

Coupled transverse motion

International Nuclear Information System (INIS)

Teng, L.C.

1989-01-01

The magnetic field in an accelerator or a storage ring is usually so designed that the horizontal (x) and the vertical (y) motions of an ion are uncoupled. However, because of imperfections in construction and alignment, some small coupling is unavoidable. In this lecture, we discuss in a general way what is known about the behaviors of coupled motions in two degrees-of-freedom. 11 refs., 6 figs

Digital anthropomorphic phantoms of non-rigid human respiratory and voluntary body motion for investigating motion correction in emission imaging

International Nuclear Information System (INIS)

Könik, Arda; Johnson, Karen L; Dasari, Paul; Pretorius, P H; Dey, Joyoni; King, Michael A; Connolly, Caitlin M; Segars, Paul W; Lindsay, Clifford

2014-01-01

The development of methods for correcting patient motion in emission tomography has been receiving increased attention. Often the performance of these methods is evaluated through simulations using digital anthropomorphic phantoms, such as the commonly used extended cardiac torso (XCAT) phantom, which models both respiratory and cardiac motion based on human studies. However, non-rigid body motion, which is frequently seen in clinical studies, is not present in the standard XCAT phantom. In addition, respiratory motion in the standard phantom is limited to a single generic trend. In this work, to obtain a more realistic representation of motion, we developed a series of individual-specific XCAT phantoms, modeling non-rigid respiratory and non-rigid body motions derived from the magnetic resonance imaging (MRI) acquisitions of volunteers. Acquisitions were performed in the sagittal orientation using the Navigator methodology. Baseline (no motion) acquisitions at end-expiration were obtained at the beginning of each imaging session for each volunteer. For the body motion studies, MRI was again acquired only at end-expiration for five body motion poses (shoulder stretch, shoulder twist, lateral bend, side roll, and axial slide). For the respiratory motion studies, an MRI was acquired during free/regular breathing. The magnetic resonance slices were then retrospectively sorted into 14 amplitude-binned respiratory states, end-expiration, end-inspiration, six intermediary states during inspiration, and six during expiration using the recorded Navigator signal. XCAT phantoms were then generated based on these MRI data by interactive alignment of the organ contours of the XCAT with the MRI slices using a graphical user interface. Thus far we have created five body motion and five respiratory motion XCAT phantoms from the MRI acquisitions of six healthy volunteers (three males and three females). Non-rigid motion exhibited by the volunteers was reflected in both respiratory

Digital anthropomorphic phantoms of non-rigid human respiratory and voluntary body motion for investigating motion correction in emission imaging

Science.gov (United States)

Könik, Arda; Connolly, Caitlin M.; Johnson, Karen L.; Dasari, Paul; Segars, Paul W.; Pretorius, P. H.; Lindsay, Clifford; Dey, Joyoni; King, Michael A.

2014-07-01

The development of methods for correcting patient motion in emission tomography has been receiving increased attention. Often the performance of these methods is evaluated through simulations using digital anthropomorphic phantoms, such as the commonly used extended cardiac torso (XCAT) phantom, which models both respiratory and cardiac motion based on human studies. However, non-rigid body motion, which is frequently seen in clinical studies, is not present in the standard XCAT phantom. In addition, respiratory motion in the standard phantom is limited to a single generic trend. In this work, to obtain a more realistic representation of motion, we developed a series of individual-specific XCAT phantoms, modeling non-rigid respiratory and non-rigid body motions derived from the magnetic resonance imaging (MRI) acquisitions of volunteers. Acquisitions were performed in the sagittal orientation using the Navigator methodology. Baseline (no motion) acquisitions at end-expiration were obtained at the beginning of each imaging session for each volunteer. For the body motion studies, MRI was again acquired only at end-expiration for five body motion poses (shoulder stretch, shoulder twist, lateral bend, side roll, and axial slide). For the respiratory motion studies, an MRI was acquired during free/regular breathing. The magnetic resonance slices were then retrospectively sorted into 14 amplitude-binned respiratory states, end-expiration, end-inspiration, six intermediary states during inspiration, and six during expiration using the recorded Navigator signal. XCAT phantoms were then generated based on these MRI data by interactive alignment of the organ contours of the XCAT with the MRI slices using a graphical user interface. Thus far we have created five body motion and five respiratory motion XCAT phantoms from the MRI acquisitions of six healthy volunteers (three males and three females). Non-rigid motion exhibited by the volunteers was reflected in both respiratory

Respiratory lung motion analysis using a nonlinear motion correction technique for respiratory-gated lung perfusion SPECT images

International Nuclear Information System (INIS)

Ue, Hidenori; Haneishi, Hideaki; Iwanaga, Hideyuki; Suga, Kazuyoshi

2007-01-01

This study evaluated the respiratory motion of lungs using a nonlinear motion correction technique for respiratory-gated single photon emission computed tomography (SPECT) images. The motion correction technique corrects the respiratory motion of the lungs nonlinearly between two-phase images obtained by respiratory-gated SPECT. The displacement vectors resulting from respiration can be computed at every location of the lungs. Respiratory lung motion analysis is carried out by calculating the mean value of the body axis component of the displacement vector in each of the 12 small regions into which the lungs were divided. In order to enable inter-patient comparison, the 12 mean values were normalized by the length of the lung region along the direction of the body axis. This method was applied to 25 Technetium (Tc)-99m-macroaggregated albumin (MAA) perfusion SPECT images, and motion analysis results were compared with the diagnostic results. It was confirmed that the respiratory lung motion reflects the ventilation function. A statistically significant difference in the amount of the respiratory lung motion was observed between the obstructive pulmonary diseases and other conditions, based on an unpaired Student's t test (P<0.0001). A difference in the motion between normal lungs and lungs with a ventilation obstruction was detected by the proposed method. This method is effective for evaluating obstructive pulmonary diseases such as pulmonary emphysema and diffuse panbronchiolitis. (author)

Five-dimensional motion compensation for respiratory and cardiac motion with cone-beam CT of the thorax region

Science.gov (United States)

Sauppe, Sebastian; Hahn, Andreas; Brehm, Marcus; Paysan, Pascal; Seghers, Dieter; Kachelrieß, Marc

2016-03-01

We propose an adapted method of our previously published five-dimensional (5D) motion compensation (MoCo) algorithm1, developed for micro-CT imaging of small animals, to provide for the first time motion artifact-free 5D cone-beam CT (CBCT) images from a conventional flat detector-based CBCT scan of clinical patients. Image quality of retrospectively respiratory- and cardiac-gated volumes from flat detector CBCT scans is deteriorated by severe sparse projection artifacts. These artifacts further complicate motion estimation, as it is required for MoCo image reconstruction. For high quality 5D CBCT images at the same x-ray dose and the same number of projections as todays 3D CBCT we developed a double MoCo approach based on motion vector fields (MVFs) for respiratory and cardiac motion. In a first step our already published four-dimensional (4D) artifact-specific cyclic motion-compensation (acMoCo) approach is applied to compensate for the respiratory patient motion. With this information a cyclic phase-gated deformable heart registration algorithm is applied to the respiratory motion-compensated 4D CBCT data, thus resulting in cardiac MVFs. We apply these MVFs on double-gated images and thereby respiratory and cardiac motion-compensated 5D CBCT images are obtained. Our 5D MoCo approach processing patient data acquired with the TrueBeam 4D CBCT system (Varian Medical Systems). Our double MoCo approach turned out to be very efficient and removed nearly all streak artifacts due to making use of 100% of the projection data for each reconstructed frame. The 5D MoCo patient data show fine details and no motion blurring, even in regions close to the heart where motion is fastest.

Temporal logic motion planning

CSIR Research Space (South Africa)

Seotsanyana, M

2010-01-01

Full Text Available In this paper, a critical review on temporal logic motion planning is presented. The review paper aims to address the following problems: (a) In a realistic situation, the motion planning problem is carried out in real-time, in a dynamic, uncertain...

Normal modified stable processes

DEFF Research Database (Denmark)

Barndorff-Nielsen, Ole Eiler; Shephard, N.

2002-01-01

Gaussian (NGIG) laws. The wider framework thus established provides, in particular, for added flexibility in the modelling of the dynamics of financial time series, of importance especially as regards OU based stochastic volatility models for equities. In the special case of the tempered stable OU process......This paper discusses two classes of distributions, and stochastic processes derived from them: modified stable (MS) laws and normal modified stable (NMS) laws. This extends corresponding results for the generalised inverse Gaussian (GIG) and generalised hyperbolic (GH) or normal generalised inverse...

Evaluation of a direct motion estimation/correction method in respiratory-gated PET/MRI with motion-adjusted attenuation.

Science.gov (United States)

Bousse, Alexandre; Manber, Richard; Holman, Beverley F; Atkinson, David; Arridge, Simon; Ourselin, Sébastien; Hutton, Brian F; Thielemans, Kris

2017-06-01

Respiratory motion compensation in PET/CT and PET/MRI is essential as motion is a source of image degradation (motion blur, attenuation artifacts). In previous work, we developed a direct method for joint image reconstruction/motion estimation (JRM) for attenuation-corrected (AC) respiratory-gated PET, which uses a single attenuation-map (μ-map). This approach was successfully implemented for respiratory-gated PET/CT, but since it relied on an accurate μ-map for motion estimation, the question of its applicability in PET/MRI is open. The purpose of this work is to investigate the feasibility of JRM in PET/MRI and to assess the robustness of the motion estimation when a degraded μ-map is used. We performed a series of JRM reconstructions from simulated PET data using a range of simulated Dixon MRI sequence derived μ-maps with wrong attenuation values in the lungs, from -100% (no attenuation) to +100% (double attenuation), as well as truncated arms. We compared the estimated motions with the one obtained from JRM in ideal conditions (no noise, true μ-map as an input). We also applied JRM on 4 patient datasets of the chest, 3 of them containing hot lesions. Patient list-mode data were gated using a principal component analysis method. We compared SUV max values of the JRM reconstructed activity images and non motion-corrected images. We also assessed the estimated motion fields by comparing the deformed JRM-reconstructed activity with individually non-AC reconstructed gates. Experiments on simulated data showed that JRM-motion estimation is robust to μ-map degradation in the sense that it produces motion fields similar to the ones obtained when using the true μ-map, regardless of the attenuation errors in the lungs (PET/MRI clinical datasets. It provides a potential alternative to existing methods where the motion fields are pre-estimated from separate MRI measurements. © 2017 University College London (UCL). Medical Physics published by Wiley Periodicals, Inc

Blind retrospective motion correction of MR images.

Science.gov (United States)

Loktyushin, Alexander; Nickisch, Hannes; Pohmann, Rolf; Schölkopf, Bernhard

2013-12-01

Subject motion can severely degrade MR images. A retrospective motion correction algorithm, Gradient-based motion correction, which significantly reduces ghosting and blurring artifacts due to subject motion was proposed. The technique uses the raw data of standard imaging sequences; no sequence modifications or additional equipment such as tracking devices are required. Rigid motion is assumed. The approach iteratively searches for the motion trajectory yielding the sharpest image as measured by the entropy of spatial gradients. The vast space of motion parameters is efficiently explored by gradient-based optimization with a convergence guarantee. The method has been evaluated on both synthetic and real data in two and three dimensions using standard imaging techniques. MR images are consistently improved over different kinds of motion trajectories. Using a graphics processing unit implementation, computation times are in the order of a few minutes for a full three-dimensional volume. The presented technique can be an alternative or a complement to prospective motion correction methods and is able to improve images with strong motion artifacts from standard imaging sequences without requiring additional data. Copyright © 2013 Wiley Periodicals, Inc., a Wiley company.

Killing (absorption) versus survival in random motion

Science.gov (United States)

Garbaczewski, Piotr

2017-09-01

We address diffusion processes in a bounded domain, while focusing on somewhat unexplored affinities between the presence of absorbing and/or inaccessible boundaries. For the Brownian motion (Lévy-stable cases are briefly mentioned) model-independent features are established of the dynamical law that underlies the short-time behavior of these random paths, whose overall lifetime is predefined to be long. As a by-product, the limiting regime of a permanent trapping in a domain is obtained. We demonstrate that the adopted conditioning method, involving the so-called Bernstein transition function, works properly also in an unbounded domain, for stochastic processes with killing (Feynman-Kac kernels play the role of transition densities), provided the spectrum of the related semigroup operator is discrete. The method is shown to be useful in the case, when the spectrum of the generator goes down to zero and no isolated minimal (ground state) eigenvalue is in existence, like in the problem of the long-term survival on a half-line with a sink at origin.

Motion correction in thoracic positron emission tomography

CERN Document Server

Gigengack, Fabian; Dawood, Mohammad; Schäfers, Klaus P

2015-01-01

Respiratory and cardiac motion leads to image degradation in Positron Emission Tomography (PET), which impairs quantification. In this book, the authors present approaches to motion estimation and motion correction in thoracic PET. The approaches for motion estimation are based on dual gating and mass-preserving image registration (VAMPIRE) and mass-preserving optical flow (MPOF). With mass-preservation, image intensity modulations caused by highly non-rigid cardiac motion are accounted for. Within the image registration framework different data terms, different variants of regularization and parametric and non-parametric motion models are examined. Within the optical flow framework, different data terms and further non-quadratic penalization are also discussed. The approaches for motion correction particularly focus on pipelines in dual gated PET. A quantitative evaluation of the proposed approaches is performed on software phantom data with accompanied ground-truth motion information. Further, clinical appl...

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.

Programmable motion of DNA origami mechanisms.

Science.gov (United States)

Marras, Alexander E; Zhou, Lifeng; Su, Hai-Jun; Castro, Carlos E

2015-01-20

DNA origami enables the precise fabrication of nanoscale geometries. We demonstrate an approach to engineer complex and reversible motion of nanoscale DNA origami machine elements. We first design, fabricate, and characterize the mechanical behavior of flexible DNA origami rotational and linear joints that integrate stiff double-stranded DNA components and flexible single-stranded DNA components to constrain motion along a single degree of freedom and demonstrate the ability to tune the flexibility and range of motion. Multiple joints with simple 1D motion were then integrated into higher order mechanisms. One mechanism is a crank-slider that couples rotational and linear motion, and the other is a Bennett linkage that moves between a compacted bundle and an expanded frame configuration with a constrained 3D motion path. Finally, we demonstrate distributed actuation of the linkage using DNA input strands to achieve reversible conformational changes of the entire structure on ∼ minute timescales. Our results demonstrate programmable motion of 2D and 3D DNA origami mechanisms constructed following a macroscopic machine design approach.

Programmable motion of DNA origami mechanisms

Science.gov (United States)

Marras, Alexander E.; Zhou, Lifeng; Su, Hai-Jun; Castro, Carlos E.

2015-01-01

DNA origami enables the precise fabrication of nanoscale geometries. We demonstrate an approach to engineer complex and reversible motion of nanoscale DNA origami machine elements. We first design, fabricate, and characterize the mechanical behavior of flexible DNA origami rotational and linear joints that integrate stiff double-stranded DNA components and flexible single-stranded DNA components to constrain motion along a single degree of freedom and demonstrate the ability to tune the flexibility and range of motion. Multiple joints with simple 1D motion were then integrated into higher order mechanisms. One mechanism is a crank–slider that couples rotational and linear motion, and the other is a Bennett linkage that moves between a compacted bundle and an expanded frame configuration with a constrained 3D motion path. Finally, we demonstrate distributed actuation of the linkage using DNA input strands to achieve reversible conformational changes of the entire structure on ∼minute timescales. Our results demonstrate programmable motion of 2D and 3D DNA origami mechanisms constructed following a macroscopic machine design approach. PMID:25561550

Applications of Phase-Based Motion Processing

Science.gov (United States)

Branch, Nicholas A.; Stewart, Eric C.

2018-01-01

Image pyramids provide useful information in determining structural response at low cost using commercially available cameras. The current effort applies previous work on the complex steerable pyramid to analyze and identify imperceptible linear motions in video. Instead of implicitly computing motion spectra through phase analysis of the complex steerable pyramid and magnifying the associated motions, instead present a visual technique and the necessary software to display the phase changes of high frequency signals within video. The present technique quickly identifies regions of largest motion within a video with a single phase visualization and without the artifacts of motion magnification, but requires use of the computationally intensive Fourier transform. While Riesz pyramids present an alternative to the computationally intensive complex steerable pyramid for motion magnification, the Riesz formulation contains significant noise, and motion magnification still presents large amounts of data that cannot be quickly assessed by the human eye. Thus, user-friendly software is presented for quickly identifying structural response through optical flow and phase visualization in both Python and MATLAB.

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.

Semi-automatic detection and correction of body organ motion, particularly cardiac motion in SPECT studies

International Nuclear Information System (INIS)

Quintana, J.C.; Caceres, F.; Vargas, P.

2002-01-01

Aim: Detect patient motion during SPECT imaging. Material and Method: SPECT study is carried out on a patient's body organ, such as the heart, and frame of image data are thereby acquired. The image data in these frames are subjected to a series of mappings and computations, from which frame containing a significant quantity of organ motion can be identified. Quantification of motion occurs by shifting some of the mapped data within a predetermined range, and selecting that data shift which minimizes the magnitude of a motion sensitive mathematical function. The sensitive mathematical function is constructed from all set of image frames using the pixel data within a region covering the body organ. Using cine display of planar image data, the operator defines the working region by marking two points, which define two horizontal lines covering the area of the body organ. This is the only operator intervention. The mathematical function integrates pixel data from all set of image frames and therefore does not use derivatives which may cause distortion in noisy data. Moreover, as a global function, this method is superior than that using frame-to-frame cross-correlation function to identify motion between adjacent frames. Using standard image processing software, the method was implemented computationally. Ten SPECT studies with movement (Sestamibi cardiac studies and 99m-ECD brain SPECT studies) were selected plus two others with no movement. The acquisition SPECT protocol for the cardiac study was as follow: Step and shoot mode, non-circular orbit, 64 stops 20s each, 64x64x16 matrix and LEHR colimator. For the brain SPECT, 128 stops over 360 0 were used. Artificial vertical displacements (±1-2 pixels) over several frames were introduced in those studies with no movement to simulate patient motion. Results: The method was successfully tested in all cases and was capable to recognize SPECT studies with no body motion as well as those with body motion (both from the

Cervical spine motion: radiographic study

International Nuclear Information System (INIS)

Morgan, J.P.; Miyabayashi, T.; Choy, S.

1986-01-01

Knowledge of the acceptable range of motion of the cervical spine of the dog is used in the radiographic diagnosis of both developmental and degenerative diseases. A series of radiographs of mature Beagle dogs was used to identify motion within sagittal and transverse planes. Positioning of the dog's head and neck was standardized, using a restraining board, and mimicked those thought to be of value in diagnostic radiology. The range of motion was greatest between C2 and C5. Reports of severe disk degeneration in the cervical spine of the Beagle describe the most severely involved disks to be C4 through C7. Thus, a high range of motion between vertebral segments does not seem to be the cause for the severe degenerative disk disease. Dorsoventral slippage between vertebral segments was seen, but was not accurately measured. Wedging of disks was clearly identified. At the atlantoaxio-occipital region, there was a high degree of motion within the sagittal plane at the atlantoaxial and atlanto-occipital joints; the measurement can be a guideline in the radiographic diagnosis of instability due to developmental anomalies in this region. Lateral motion within the transverse plane was detected at the 2 joints; however, motion was minimal, and the measurements seemed to be less accurate because of rotation of the cervical spine. Height of the vertebral canal was consistently noted to be greater at the caudal orifice, giving some warning to the possibility of overdiagnosis in suspected instances of cervical spondylopathy

Method through motion

DEFF Research Database (Denmark)

Steijn, Arthur

2016-01-01

Contemporary scenography often consists of video-projected motion graphics. The field is lacking in academic methods and rigour: descriptions and models relevant for the creation as well as in the analysis of existing works. In order to understand the phenomenon of motion graphics in a scenographic...... construction as a support to working systematically practice-led research project. The design model is being developed through design laboratories and workshops with students and professionals who provide feedback that lead to incremental improvements. Working with this model construction-as-method reveals...... context, I have been conducting a practice-led research project. Central to the project is construction of a design model describing sets of procedures, concepts and terminology relevant for design and studies of motion graphics in spatial contexts. The focus of this paper is the role of model...

Uses of stable isotopes

International Nuclear Information System (INIS)

Axente, Damian

1998-01-01

The most important fields of stable isotope use with examples are presented. These are: 1. Isotope dilution analysis: trace analysis, measurements of volumes and masses; 2. Stable isotopes as tracers: transport phenomena, environmental studies, agricultural research, authentication of products and objects, archaeometry, studies of reaction mechanisms, structure and function determination of complex biological entities, studies of metabolism, breath test for diagnostic; 3. Isotope equilibrium effects: measurement of equilibrium effects, investigation of equilibrium conditions, mechanism of drug action, study of natural processes, water cycle, temperature measurements; 4. Stable isotope for advanced nuclear reactors: uranium nitride with 15 N as nuclear fuel, 157 Gd for reactor control. In spite of some difficulties of stable isotope use, particularly related to the analytical techniques, which are slow and expensive, the number of papers reporting on this subject is steadily growing as well as the number of scientific meetings organized by International Isotope Section and IAEA, Gordon Conferences, and regional meeting in Germany, France, etc. Stable isotope application development on large scale is determined by improving their production technologies as well as those of labeled compound and the analytical techniques. (author)

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

SU-C-210-04: Considerable Pancreatic Tumor Motion During Breath-Hold Measured Using Intratumoral Fiducials On Fluoroscopic Movies

Energy Technology Data Exchange (ETDEWEB)

Lens, E; Horst, A van der; Versteijne, E; Tienhoven, G van; Bel, A [Academic Medical Center, Amsterdam (Netherlands)

2015-06-15

Purpose: Using a breath hold (BH) technique during radiotherapy of pancreatic tumors is expected to reduce intra-fractional motion. The aim of this study was to evaluate the tumor motion during BH. Methods: In this pilot study, we included 8 consecutive pancreatic cancer patients. All had 2– 4 intratumoral gold fiducials. Patients were asked to perform 3 consecutive 30-second end-inhale BHs on day 5, 10 and 15 of their three-week treatment. During BH, airflow through a mouthpiece was measured using a spirometer. Any inadvertent flow of air during BH was monitored for all patients. We measured tumor motion on lateral fluoroscopic movies (57 in total) made during BH. In each movie the fiducials as a group were tracked over time in superior-inferior (SI) and anterior-posterior (AP) direction using 2-D image correlation between consecutive frames. We determined for each patient the range of intra-BH motion over all movies; we also determined the absolute means and standard deviations (SDs) for the entire patient group. Additionally, we investigated the relation between inadvertent airflow during BH and the intra-BH motion. Results: We found intra-BH tumor motion of up to 12.5 mm (range, 1.0–12.5 mm) in SI direction and up to 8.0 mm (range, 1.0–8.0 mm) in AP direction. The absolute mean motion over the patient population was 4.7 (SD: 3.0) mm and 2.8 (SD: 1.2) mm in the SI and AP direction, respectively. Patients were able to perform stable consecutive BHs; during only 20% of the movies we found very small airflows (≤ 65 ml). These were mostly stepwise in nature and could not explain the continuous tumor motions we observed. Conclusion: We found substantial (up to 12.5 mm) pancreatic tumor motion during BHs. We found minimal inadvertent airflow, seen only during a minority of BHs, and this did not explain the obtained results. This work was supported by the foundation Bergh in het Zadel through the Dutch Cancer Society (KWF Kankerbestrijding) project No. UVA 2011-5271.

Visual Motion Perception

Science.gov (United States)

1991-08-15

displace- ment limit for motion in random dots," Vision Res., 24, 293-300. Pantie , A. & K. Turano (1986) "Direct comparisons of apparent motions...Hicks & AJ, Pantie (1978) "Apparent movement of successively generated subjec. uve figures," Perception, 7, 371-383. Ramachandran. V.S. & S.M. Anstis...thanks think deaf girl until world uncle flag home talk finish short thee our screwdiver sonry flower wrCstlir~g plan week wait accident guilty tree

Improved motion description for action classification

NARCIS (Netherlands)

Jain, M.; Jégou, H.; Bouthemy, P.

2016-01-01

Even though the importance of explicitly integrating motion characteristics in video descriptions has been demonstrated by several recent papers on action classification, our current work concludes that adequately decomposing visual motion into dominant and residual motions, i.e., camera and scene

Perception of biological motion in visual agnosia

Directory of Open Access Journals (Sweden)

Elisabeth eHuberle

2012-08-01

Full Text Available Over the past twenty-five years, visual processing has been discussed in the context of the dual stream hypothesis consisting of a ventral (‘what' and a dorsal ('where' visual information processing pathway. Patients with brain damage of the ventral pathway typically present with signs of visual agnosia, the inability to identify and discriminate objects by visual exploration, but show normal perception of motion perception. A dissociation between the perception of biological motion and non-biological motion has been suggested: Perception of biological motion might be impaired when 'non-biological' motion perception is intact and vice versa. The impact of object recognition on the perception of biological motion remains unclear. We thus investigated this question in a patient with severe visual agnosia, who showed normal perception of non-biological motion. The data suggested that the patient's perception of biological motion remained largely intact. However, when tested with objects constructed of coherently moving dots (‘Shape-from-Motion’, recognition was severely impaired. The results are discussed in the context of possible mechanisms of biological motion perception.

Stable isotopes labelled compounds

International Nuclear Information System (INIS)

1982-09-01

The catalogue on stable isotopes labelled compounds offers deuterium, nitrogen-15, and multiply labelled compounds. It includes: (1) conditions of sale and delivery, (2) the application of stable isotopes, (3) technical information, (4) product specifications, and (5) the complete delivery programme

Stable Boundary Layer Issues

NARCIS (Netherlands)

Steeneveld, G.J.

2012-01-01

Understanding and prediction of the stable atmospheric boundary layer is a challenging task. Many physical processes are relevant in the stable boundary layer, i.e. turbulence, radiation, land surface coupling, orographic turbulent and gravity wave drag, and land surface heterogeneity. The

Validation of the Leap Motion Controller using markered motion capture technology.

Science.gov (United States)

Smeragliuolo, Anna H; Hill, N Jeremy; Disla, Luis; Putrino, David

2016-06-14

The Leap Motion Controller (LMC) is a low-cost, markerless motion capture device that tracks hand, wrist and forearm position. Integration of this technology into healthcare applications has begun to occur rapidly, making validation of the LMC׳s data output an important research goal. Here, we perform a detailed evaluation of the kinematic data output from the LMC, and validate this output against gold-standard, markered motion capture technology. We instructed subjects to perform three clinically-relevant wrist (flexion/extension, radial/ulnar deviation) and forearm (pronation/supination) movements. The movements were simultaneously tracked using both the LMC and a marker-based motion capture system from Motion Analysis Corporation (MAC). Adjusting for known inconsistencies in the LMC sampling frequency, we compared simultaneously acquired LMC and MAC data by performing Pearson׳s correlation (r) and root mean square error (RMSE). Wrist flexion/extension and radial/ulnar deviation showed good overall agreement (r=0.95; RMSE=11.6°, and r=0.92; RMSE=12.4°, respectively) with the MAC system. However, when tracking forearm pronation/supination, there were serious inconsistencies in reported joint angles (r=0.79; RMSE=38.4°). Hand posture significantly influenced the quality of wrist deviation (P<0.005) and forearm supination/pronation (P<0.001), but not wrist flexion/extension (P=0.29). We conclude that the LMC is capable of providing data that are clinically meaningful for wrist flexion/extension, and perhaps wrist deviation. It cannot yet return clinically meaningful data for measuring forearm pronation/supination. Future studies should continue to validate the LMC as updated versions of their software are developed. Copyright © 2016 Elsevier Ltd. All rights reserved.

Plume meander and dispersion in a stable boundary layer

Science.gov (United States)

Hiscox, April L.; Miller, David R.; Nappo, Carmen J.

2010-11-01

Continuous lidar measurements of elevated plume dispersion and corresponding micrometeorology data are analyzed to establish the relationship between plume behavior and nocturnal boundary layer dynamics. Contrasting nights of data from the JORNADA field campaign in the New Mexico desert are analyzed. The aerosol lidar measurements were used to separate the plume diffusion (plume spread) from plume meander (displacement). Mutiresolution decomposition was used to separate the turbulence scale (90 s). Durations of turbulent kinetic energy stationarity and the wind steadiness were used to characterize the local scale and submesoscale turbulence. Plume meander, driven by submesoscale wind motions, was responsible for most of the total horizontal plume dispersion in weak and variable winds and strong stability. This proportion was reduced in high winds (i.e., >4 m s-1), weakly stable conditions but remained the dominant dispersion mechanism. The remainder of the plume dispersion in all cases was accounted for by internal spread of the plume, which is a small eddy diffusion process driven by turbulence. Turbulence stationarity and the wind steadiness are demonstrated to be closely related to plume diffusion and plume meander, respectively.

Three-dimensional organization of vestibular related eye movements to rotational motion in pigeons

Science.gov (United States)

Dickman, J. D.; Beyer, M.; Hess, B. J.

2000-01-01

During rotational motions, compensatory eye movement adjustments must continually occur in order to maintain objects of visual interest as stable images on the retina. In the present study, the three-dimensional organization of the vestibulo-ocular reflex in pigeons was quantitatively examined. Rotations about different head axes produced horizontal, vertical, and torsional eye movements, whose component magnitude was dependent upon the cosine of the stimulus axis relative to the animal's visual axis. Thus, the three-dimensional organization of the VOR in pigeons appears to be compensatory for any direction of head rotation. Frequency responses of the horizontal, vertical, and torsional slow phase components exhibited high pass filter properties with dominant time constants of approximately 3 s.

Hydrodynamics of multi-sized particles in stable regime of a swirling bed

Energy Technology Data Exchange (ETDEWEB)

Miin, Chin Swee; Sulaiman, Shaharin Anwar; Raghavan, Vijay Raj; Heikal, Morgan Raymond; Naz, Muhammad Yasin [Universiti Teknologi PETRONAS, Perak (Malaysia)

2015-11-15

Using particle imaging velocimetry (PIV), we observed particle motion within the stable operating regime of a swirling fluidized bed with an annular blade distributor. This paper presents velocity profiles of particle flow in an effort to determine effects from blade angle, particle size and shape and bed weight on characteristics of a swirling fluidized bed. Generally, particle velocity increased with airflow rate and shallow bed height, but decreased with bed weight. A 3 .deg. increase in blade angle reduced particle velocity by approximately 18%. In addition, particle shape, size and bed weight affected various characteristics of the swirling regime. Swirling began soon after incipience in the form of a supra-linear curve, which is the characteristic of a swirling regime. The relationship between particle and gas velocities enabled us to predict heat and mass transfer rates between gas and particles.

Motion-induced dose artifacts in helical tomotherapy

Energy Technology Data Exchange (ETDEWEB)

Kim, Bryan; Chen, Jeff; Battista, Jerry [London Regional Cancer Program, London Health Sciences Centre, London, ON (Canada); Kron, Tomas [Peter MacCallum Cancer Center, Melbourne (Australia)], E-mail: bryan.kim@lhsc.on.ca

2009-10-07

Tumor motion is a particular concern for a complex treatment modality such as helical tomotherapy, where couch position, gantry rotation and MLC leaf opening all change with time. In the present study, we have investigated the impact of tumor motion for helical tomotherapy, which could result in three distinct motion-induced dose artifacts, namely (1) dose rounding, (2) dose rippling and (3) IMRT leaf opening asynchronization effect. Dose rounding and dose rippling effects have been previously described, while the IMRT leaf opening asynchronization effect is a newly discovered motion-induced dose artifact. Dose rounding is the penumbral widening of a delivered dose distribution near the edges of a target volume along the direction of tumor motion. Dose rippling is a series of periodic dose peaks and valleys observed within the target region along the direction of couch motion, due to an asynchronous interplay between the couch motion and the longitudinal component of tumor motion. The IMRT leaf opening asynchronization effect is caused by an asynchronous interplay between the temporal patterns of leaf openings and tumor motion. The characteristics of each dose artifact were investigated individually as functions of target motion amplitude and period for both non-IMRT and IMRT helical tomotherapy cases, through computer simulation modeling and experimental verification. The longitudinal dose profiles generated by the simulation program agreed with the experimental data within {+-}0.5% and {+-}1.5% inside the PTV region for the non-IMRT and IMRT cases, respectively. The dose rounding effect produced a penumbral increase up to 20.5 mm for peak-to-peak target motion amplitudes ranging from 1.0 cm to 5.0 cm. Maximum dose rippling magnitude of 25% was calculated, when the target motion period approached an unusually high value of 10 s. The IMRT leaf opening asynchronization effect produced dose differences ranging from -29% to 7% inside the PTV region. This information

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 ...

Projectile Motion Hoop Challenge

Science.gov (United States)

Jordan, Connor; Dunn, Amy; Armstrong, Zachary; Adams, Wendy K.

2018-01-01

Projectile motion is a common phenomenon that is used in introductory physics courses to help students understand motion in two dimensions. Authors have shared a range of ideas for teaching this concept and the associated kinematics in "The Physics Teacher" ("TPT"); however, the "Hoop Challenge" is a new setup not…

On the consequences of strong stable stratification at the top of earth's outer core

Science.gov (United States)

Bloxham, Jeremy

1990-01-01

The consequences of strong stable stratification at the top of the earth's fluid outer core are considered, concentrating on the generation of the geomagnetic secular variation. It is assumed that the core near the core-mantle boundary is both strongly stably stratified and free of Lorentz forces: it is found that this set of assumptions severely limits the class of possible motions, none of which is compatible with the geomagnetic secular variation. Relaxing either assumption is adequate: tangentially geostrophic flows are consistent with the secular variation if the assumption that the core is strongly stably stratified is relaxed (while retaining the assumption that Lorentz forces are negligible); purely toroidal flows may explain the secular variation if Lorentz forces are included.

Ground motion predictions

Energy Technology Data Exchange (ETDEWEB)

Loux, P C [Environmental Research Corporation, Alexandria, VA (United States)

1969-07-01

Nuclear generated ground motion is defined and then related to the physical parameters that cause it. Techniques employed for prediction of ground motion peak amplitude, frequency spectra and response spectra are explored, with initial emphasis on the analysis of data collected at the Nevada Test Site (NTS). NTS postshot measurements are compared with pre-shot predictions. Applicability of these techniques to new areas, for example, Plowshare sites, must be questioned. Fortunately, the Atomic Energy Commission is sponsoring complementary studies to improve prediction capabilities primarily in new locations outside the NTS region. Some of these are discussed in the light of anomalous seismic behavior, and comparisons are given showing theoretical versus experimental results. In conclusion, current ground motion prediction techniques are applied to events off the NTS. Predictions are compared with measurements for the event Faultless and for the Plowshare events, Gasbuggy, Cabriolet, and Buggy I. (author)

Ground motion predictions

International Nuclear Information System (INIS)

Loux, P.C.

1969-01-01

Nuclear generated ground motion is defined and then related to the physical parameters that cause it. Techniques employed for prediction of ground motion peak amplitude, frequency spectra and response spectra are explored, with initial emphasis on the analysis of data collected at the Nevada Test Site (NTS). NTS postshot measurements are compared with pre-shot predictions. Applicability of these techniques to new areas, for example, Plowshare sites, must be questioned. Fortunately, the Atomic Energy Commission is sponsoring complementary studies to improve prediction capabilities primarily in new locations outside the NTS region. Some of these are discussed in the light of anomalous seismic behavior, and comparisons are given showing theoretical versus experimental results. In conclusion, current ground motion prediction techniques are applied to events off the NTS. Predictions are compared with measurements for the event Faultless and for the Plowshare events, Gasbuggy, Cabriolet, and Buggy I. (author)

Using Simulated Ground Motions to Constrain Near-Source Ground Motion Prediction Equations in Areas Experiencing Induced Seismicity

Science.gov (United States)

Bydlon, S. A.; Dunham, E. M.

2016-12-01

Recent increases in seismic activity in historically quiescent areas such as Oklahoma, Texas, and Arkansas, including large, potentially induced events such as the 2011 Mw 5.6 Prague, OK, earthquake, have spurred the need for investigation into expected ground motions associated with these seismic sources. The neoteric nature of this seismicity increase corresponds to a scarcity of ground motion recordings within 50 km of earthquakes Mw 3.0 and greater, with increasing scarcity at larger magnitudes. Gathering additional near-source ground motion data will help better constraints on regional ground motion prediction equations (GMPEs) and will happen over time, but this leaves open the possibility of damaging earthquakes occurring before potential ground shaking and seismic hazard in these areas are properly understood. To aid the effort of constraining near-source GMPEs associated with induced seismicity, we integrate synthetic ground motion data from simulated earthquakes into the process. Using the dynamic rupture and seismic wave propagation code waveqlab3d, we perform verification and validation exercises intended to establish confidence in simulated ground motions for use in constraining GMPEs. We verify the accuracy of our ground motion simulator by performing the PEER/SCEC layer-over-halfspace comparison problem LOH.1 Validation exercises to ensure that we are synthesizing realistic ground motion data include comparisons to recorded ground motions for specific earthquakes in target areas of Oklahoma between Mw 3.0 and 4.0. Using a 3D velocity structure that includes a 1D structure with additional small-scale heterogeneity, the properties of which are based on well-log data from Oklahoma, we perform ground motion simulations of small (Mw 3.0 - 4.0) earthquakes using point moment tensor sources. We use the resulting synthetic ground motion data to develop GMPEs for small earthquakes in Oklahoma. Preliminary results indicate that ground motions can be amplified

Analysis of motion in speed skating

Science.gov (United States)

Koga, Yuzo; Nishimura, Tetsu; Watanabe, Naoki; Okamoto, Kousuke; Wada, Yuhei

1997-03-01

A motion on sports has been studied by many researchers from the view of the medical, psychological and mechanical fields. Here, we try to analyze a speed skating motion dynamically for an aim of performing the best record. As an official competition of speed skating is performed on the round rink, the skating motion must be studied on the three phases, that is, starting phase, straight and curved course skating phase. It is indispensable to have a visual data of a skating motion in order to analyze kinematically. So we took a several subject's skating motion by 8 mm video cameras in order to obtain three dimensional data. As the first step, the movement of the center of gravity of skater (abbreviate to C. G.) is discussed in this paper, because a skating motion is very complicated. The movement of C. G. will give an information of the reaction force to a skate blade from the surface of ice. We discuss the discrepancy of several skating motion by studied subjects. Our final goal is to suggest the best skating form for getting the finest record.

Structure of acid-stable carmine.

Science.gov (United States)

Sugimoto, Naoki; Kawasaki, Yoko; Sato, Kyoko; Aoki, Hiromitsu; Ichi, Takahito; Koda, Takatoshi; Yamazaki, Takeshi; Maitani, Tamio

2002-02-01

Acid-stable carmine has recently been distributed in the U.S. market because of its good acid stability, but it is not permitted in Japan. We analyzed and determined the structure of the major pigment in acid-stable carmine, in order to establish an analytical method for it. Carminic acid was transformed into a different type of pigment, named acid-stable carmine, through amination when heated in ammonia solution. The features of the structure were clarified using a model compound, purpurin, in which the orientation of hydroxyl groups on the A ring of the anthraquinone skeleton is the same as that of carminic acid. By spectroscopic means and the synthesis of acid-stable carmine and purpurin derivatives, the structure of the major pigment in acid-stable carmine was established as 4-aminocarminic acid, a novel compound.

Motion patterns and phase-transition of a defender-intruder problem and optimal interception strategy of the defender

Science.gov (United States)

Wang, Jiangliu; Li, Wei

2015-10-01

In this paper, we consider a defense-intrusion interaction, in which an intruder is attracted by a protected stationary target but repulsed by a defender; while the defender tries to move towards an appropriate interception position (IP) between the intruder and the target in order to intercept the intruder and expel the intruder away from the target as maximum as possible. Intuitionally, to keep the intruder further away, one may wonder that: is it a better strategy for the defender trying to approach the intruder as near as possible? Unexpectedly and interestingly enough, this is not always the case. We first introduce the flexibility for IP selection, then investigate the system dynamics and the stable motion patterns, and characterize the phase-transition surface for the motion patterns. We show that, the phase-transition surface just defines the optimal interception strategy of the defender for IP selection; and from the perspective of mobility of agents, the optimal strategy just depends on relative mobility of the two agents.

ROBUST MOTION SEGMENTATION FOR HIGH DEFINITION VIDEO SEQUENCES USING A FAST MULTI-RESOLUTION MOTION ESTIMATION BASED ON SPATIO-TEMPORAL TUBES

OpenAIRE

Brouard , Olivier; Delannay , Fabrice; Ricordel , Vincent; Barba , Dominique

2007-01-01

4 pages; International audience; Motion segmentation methods are effective for tracking video objects. However, objects segmentation methods based on motion need to know the global motion of the video in order to back-compensate it before computing the segmentation. In this paper, we propose a method which estimates the global motion of a High Definition (HD) video shot and then segments it using the remaining motion information. First, we develop a fast method for multi-resolution motion est...

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.

Applications of stable isotopes

International Nuclear Information System (INIS)

Letolle, R.; Mariotti, A.; Bariac, T.

1991-06-01

This report reviews the historical background and the properties of stable isotopes, the methods used for their measurement (mass spectrometry and others), the present technics for isotope enrichment and separation, and at last the various present and foreseeable application (in nuclear energy, physical and chemical research, materials industry and research; tracing in industrial, medical and agronomical tests; the use of natural isotope variations for environmental studies, agronomy, natural resources appraising: water, minerals, energy). Some new possibilities in the use of stable isotope are offered. A last chapter gives the present state and forecast development of stable isotope uses in France and Europe

Chaos control of Hastings–Powell model by combining chaotic motions

Energy Technology Data Exchange (ETDEWEB)

Danca, Marius-F., E-mail: danca@rist.ro [Romanian Institute of Science and Technology, 400487 Cluj-Napoca (Romania); Chattopadhyay, Joydev, E-mail: joydev@isical.ac.in [Agricultural and Ecological Research Unit Indian Statistical Institute, 203, B. T. Road, Kolkata 700 108 (India)

2016-04-15

In this paper, we propose a Parameter Switching (PS) algorithm as a new chaos control method for the Hastings–Powell (HP) system. The PS algorithm is a convergent scheme that switches the control parameter within a set of values while the controlled system is numerically integrated. The attractor obtained with the PS algorithm matches the attractor obtained by integrating the system with the parameter replaced by the averaged value of the switched parameter values. The switching rule can be applied periodically or randomly over a set of given values. In this way, every stable cycle of the HP system can be approximated if its underlying parameter value equalizes the average value of the switching values. Moreover, the PS algorithm can be viewed as a generalization of Parrondo's game, which is applied for the first time to the HP system, by showing that losing strategy can win: “losing + losing = winning.” If “loosing” is replaced with “chaos” and, “winning” with “order” (as the opposite to “chaos”), then by switching the parameter value in the HP system within two values, which generate chaotic motions, the PS algorithm can approximate a stable cycle so that symbolically one can write “chaos + chaos = regular.” Also, by considering a different parameter control, new complex dynamics of the HP model are revealed.

Chaos control of Hastings-Powell model by combining chaotic motions.

Science.gov (United States)

Danca, Marius-F; Chattopadhyay, Joydev

2016-04-01

In this paper, we propose a Parameter Switching (PS) algorithm as a new chaos control method for the Hastings-Powell (HP) system. The PS algorithm is a convergent scheme that switches the control parameter within a set of values while the controlled system is numerically integrated. The attractor obtained with the PS algorithm matches the attractor obtained by integrating the system with the parameter replaced by the averaged value of the switched parameter values. The switching rule can be applied periodically or randomly over a set of given values. In this way, every stable cycle of the HP system can be approximated if its underlying parameter value equalizes the average value of the switching values. Moreover, the PS algorithm can be viewed as a generalization of Parrondo's game, which is applied for the first time to the HP system, by showing that losing strategy can win: "losing + losing = winning." If "loosing" is replaced with "chaos" and, "winning" with "order" (as the opposite to "chaos"), then by switching the parameter value in the HP system within two values, which generate chaotic motions, the PS algorithm can approximate a stable cycle so that symbolically one can write "chaos + chaos = regular." Also, by considering a different parameter control, new complex dynamics of the HP model are revealed.

Chaos control of Hastings–Powell model by combining chaotic motions

International Nuclear Information System (INIS)

Danca, Marius-F.; Chattopadhyay, Joydev

2016-01-01

In this paper, we propose a Parameter Switching (PS) algorithm as a new chaos control method for the Hastings–Powell (HP) system. The PS algorithm is a convergent scheme that switches the control parameter within a set of values while the controlled system is numerically integrated. The attractor obtained with the PS algorithm matches the attractor obtained by integrating the system with the parameter replaced by the averaged value of the switched parameter values. The switching rule can be applied periodically or randomly over a set of given values. In this way, every stable cycle of the HP system can be approximated if its underlying parameter value equalizes the average value of the switching values. Moreover, the PS algorithm can be viewed as a generalization of Parrondo's game, which is applied for the first time to the HP system, by showing that losing strategy can win: “losing + losing = winning.” If “loosing” is replaced with “chaos” and, “winning” with “order” (as the opposite to “chaos”), then by switching the parameter value in the HP system within two values, which generate chaotic motions, the PS algorithm can approximate a stable cycle so that symbolically one can write “chaos + chaos = regular.” Also, by considering a different parameter control, new complex dynamics of the HP model are revealed.

Figure-ground segregation modulates apparent motion.

Science.gov (United States)

Ramachandran, V S; Anstis, S

1986-01-01

We explored the relationship between figure-ground segmentation and apparent motion. Results suggest that: static elements in the surround can eliminate apparent motion of a cluster of dots in the centre, but only if the cluster and surround have similar "grain" or texture; outlines that define occluding surfaces are taken into account by the motion mechanism; the brain uses a hierarchy of precedence rules in attributing motion to different segments of the visual scene. Being designated as "figure" confers a high rank in this scheme of priorities.

39 CFR 959.26 - Motion for reconsideration.

Science.gov (United States)

2010-07-01

... clearly setting forth the points of fact and of law relied upon in support of said motion. ... 39 Postal Service 1 2010-07-01 2010-07-01 false Motion for reconsideration. 959.26 Section 959.26... PRIVATE EXPRESS STATUTES § 959.26 Motion for reconsideration. A party may file a motion for...

Sensing Movement: Microsensors for Body Motion Measurement

Directory of Open Access Journals (Sweden)

Hansong Zeng

2011-01-01

Full Text Available Recognition of body posture and motion is an important physiological function that can keep the body in balance. Man-made motion sensors have also been widely applied for a broad array of biomedical applications including diagnosis of balance disorders and evaluation of energy expenditure. This paper reviews the state-of-the-art sensing components utilized for body motion measurement. The anatomy and working principles of a natural body motion sensor, the human vestibular system, are first described. Various man-made inertial sensors are then elaborated based on their distinctive sensing mechanisms. In particular, both the conventional solid-state motion sensors and the emerging non solid-state motion sensors are depicted. With their lower cost and increased intelligence, man-made motion sensors are expected to play an increasingly important role in biomedical systems for basic research as well as clinical diagnostics.

The notion of the motion: the neurocognition of motion lines in visual narratives.

Science.gov (United States)

Cohn, Neil; Maher, Stephen

2015-03-19

Motion lines appear ubiquitously in graphic representation to depict the path of a moving object, most popularly in comics. Some researchers have argued that these graphic signs directly tie to the "streaks" appearing in the visual system when a viewer tracks an object (Burr, 2000), despite the fact that previous studies have been limited to offline measurements. Here, we directly examine the cognition of motion lines by comparing images in comic strips that depicted normal motion lines with those that either had no lines or anomalous, reversed lines. In Experiment 1, shorter viewing times appeared to images with normal lines than those with no lines, which were shorter than those with anomalous lines. In Experiment 2, measurements of event-related potentials (ERPs) showed that, compared to normal lines, panels with no lines elicited a posterior positivity that was distinct from the frontal positivity evoked by anomalous lines. These results suggested that motion lines aid in the comprehension of depicted events. LORETA source localization implicated greater activation of visual and language areas when understanding was made more difficult by anomalous lines. Furthermore, in both experiments, participants' experience reading comics modulated these effects, suggesting motion lines are not tied to aspects of the visual system, but rather are conventionalized parts of the "vocabulary" of the visual language of comics. Copyright © 2015 Elsevier B.V. All rights reserved.

Theory of motion for monopole-dipole singularities of classical Yang-Mills-Higgs fields. I. Laws of motion

International Nuclear Information System (INIS)

Drechsler, W.; Havas, P.; Rosenblum, A.

1984-01-01

In two recent papers, the general form of the laws of motion for point particles which are multipole sources of the classical coupled Yang-Mills-Higgs fields was determined by Havas, and for the special case of monopole singularities of a Yang-Mills field an iteration procedure was developed by Drechsler and Rosenblum to obtain the equations of motion of mass points, i.e., the laws of motion including the explicit form of the fields of all interacting particles. In this paper we give a detailed derivation of the laws of motion of monopole-dipole singularities of the coupled Yang-Mills-Higgs fields for point particles with mass and spin, following a procedure first applied by Mathisson and developed by Havas. To obtain the equations of motion, a systematic approximation method is developed in the following paper for the solution of the nonlinear field equations and determination of the fields entering the laws of motion found here to any given order in the coupling constant g

The Effectiveness of Simulator Motion in the Transfer of Performance on a Tracking Task Is Influenced by Vision and Motion Disturbance Cues.

Science.gov (United States)

Grundy, John G; Nazar, Stefan; O'Malley, Shannon; Mohrenshildt, Martin V; Shedden, Judith M

2016-06-01

To examine the importance of platform motion to the transfer of performance in motion simulators. The importance of platform motion in simulators for pilot training is strongly debated. We hypothesized that the type of motion (e.g., disturbance) contributes significantly to performance differences. Participants used a joystick to perform a target tracking task in a pod on top of a MOOG Stewart motion platform. Five conditions compared training without motion, with correlated motion, with disturbance motion, with disturbance motion isolated to the visual display, and with both correlated and disturbance motion. The test condition involved the full motion model with both correlated and disturbance motion. We analyzed speed and accuracy across training and test as well as strategic differences in joystick control. Training with disturbance cues produced critical behavioral differences compared to training without disturbance; motion itself was less important. Incorporation of disturbance cues is a potentially important source of variance between studies that do or do not show a benefit of motion platforms in the transfer of performance in simulators. Potential applications of this research include the assessment of the importance of motion platforms in flight simulators, with a focus on the efficacy of incorporating disturbance cues during training. © 2016, Human Factors and Ergonomics Society.

Motion sensing energy controller

International Nuclear Information System (INIS)

Saphir, M.E.; Reed, M.A.

1984-01-01

A moving object sensing processor responsive to slowly varying motions of a human being or other moving object in a zone of interest employs high frequency pulse modulated non-visible radiation generated by a radiation generating source, such as an LED, and detected by a detector sensitive to radiation of a preselected wavelength which generates electrical signals representative of the reflected radiation received from the zone of interest. The detectorsignals are processed to normalize the base level and remove variations due to background level changes, and slowly varying changes in the signals are detected by a bi-polar threshold detector. The control signals generated by the threshold detector in response to slowly varying motion are used to control the application of power to a utilization device, such as a set of fluoroescent lights in a room, the power being applied in response to detection of such motion and being automatically terminated in the absence of such motion after a predetermined time period established by a settable incrementable counter

Identification of resonant earthquake ground motion

Indian Academy of Sciences (India)

Resonant ground motion has been observed in earthquake records measured at several parts of the world. This class of ground motion is characterized by its energy being contained in a narrow frequency band. This paper develops measures to quantify the frequency content of the ground motion using the entropy ...

Internal Motion Estimation by Internal-external Motion Modeling for Lung Cancer Radiotherapy.

Science.gov (United States)

Chen, Haibin; Zhong, Zichun; Yang, Yiwei; Chen, Jiawei; Zhou, Linghong; Zhen, Xin; Gu, Xuejun

2018-02-27

The aim of this study is to develop an internal-external correlation model for internal motion estimation for lung cancer radiotherapy. Deformation vector fields that characterize the internal-external motion are obtained by respectively registering the internal organ meshes and external surface meshes from the 4DCT images via a recently developed local topology preserved non-rigid point matching algorithm. A composite matrix is constructed by combing the estimated internal phasic DVFs with external phasic and directional DVFs. Principle component analysis is then applied to the composite matrix to extract principal motion characteristics, and generate model parameters to correlate the internal-external motion. The proposed model is evaluated on a 4D NURBS-based cardiac-torso (NCAT) synthetic phantom and 4DCT images from five lung cancer patients. For tumor tracking, the center of mass errors of the tracked tumor are 0.8(±0.5)mm/0.8(±0.4)mm for synthetic data, and 1.3(±1.0)mm/1.2(±1.2)mm for patient data in the intra-fraction/inter-fraction tracking, respectively. For lung tracking, the percent errors of the tracked contours are 0.06(±0.02)/0.07(±0.03) for synthetic data, and 0.06(±0.02)/0.06(±0.02) for patient data in the intra-fraction/inter-fraction tracking, respectively. The extensive validations have demonstrated the effectiveness and reliability of the proposed model in motion tracking for both the tumor and the lung in lung cancer radiotherapy.

Galileo and the Problems of Motion

Science.gov (United States)

Hooper, Wallace Edd

Galileo's science of motion changed natural philosophy. His results initiated a broad human awakening to the intricate new world of physical order found in the midst of familiar operations of nature. His thinking was always based squarely on the academic traditions of the spiritual old world. He advanced physics by new standards of judgment drawn from mechanics and geometry, and disciplined observation of the world. My study first determines the order of composition of the earliest essays on motion and physics, ca. 1588 -1592, from internal evidence, and bibliographic evidence. There are clear signs of a Platonist critique of Aristotle, supported by Archimedes, in the Ten Section Version of On Motion, written ca. 1588, and probably the earliest of his treatises on motion or physics. He expanded upon his opening Platonic -Archimedean position by investigating the ideas of scholastic critics of Aristotle, including the Doctores Parisienses, found in his readings of the Jesuit Professors at the Collegio Romano. Their influences surfaced clearly in Galileo's Memoranda on Motion and the Dialogue on Motion, and in On Motion, which followed, ca. 1590-1592. At the end of his sojourn in Pisa, Galileo opened the road to the new physics by solving an important problem in the mechanics of Pappus, concerning motion along inclined planes. My study investigates why Galileo gave up attempts to establish a ratio between speed and weight, and why he began to seek the ratios of time and distance and speed, by 1602. It also reconstructs Galileo's development of the 1604 principle, seeking to outline its invention, elaboration, and abandonment. Then, I try to show that we have a record of Galileo's moment of recognition of the direct relation between the time of fall and the accumulated speed of motion--that great affinity between time and motion and the key to the new science of motion established before 1610. Evidence also ties the discovery of the time affinity directly to Galileo

Exploring the 7:4 mean motion resonance—I: Dynamical evolution of classical transneptunian objects

Science.gov (United States)

Lykawka, Patryk Sofia; Mukai, Tadashi

2005-09-01

In the transneptunian classical region ( 42AUunexpected orbital excitation in eccentricity and inclination, dynamically distinct populations and the presence of chaotic regions are observed. For instance, the 7:4 mean motion resonance ( a˜43.7AU) appears to have been causing unique dynamical excitation according to observational evidences, namely, an apparent shallow gap in number density and anomalies in the colour distribution, both features enhanced near the 7:4 mean motion resonance location. In order to investigate the resonance dynamics, we present extensive computer simulation results totalizing almost 10,000 test particles under the effect of the four giant planets for the age of the solar system. A chaotic diffusion experiment was also performed to follow tracks in phase space over 4-5 Gyr. The 7:4 mean motion resonance is weakly chaotic causing irregular eccentricity and inclination evolution for billions of years. Most 7:4 resonant particles suffered significant eccentricities and/or inclinations excitation, an outcome shared even by those located in the vicinity of the resonance. Particles in stable resonance locking are rare and usually had 0.25typically leaving the resonance (and being scattered) after reaching a critical e˜0.2. The escape happened in 10 8-10 9 yr time scales. Concerning the inclination dependence for 7:4 resonants, we found strong instability islands for approximately i>10°. Taking into account those particles still locked in the resonance at the end of the simulations, we determined a retainability of 12-15% for real 7:4 resonant transneptunian objects (TNOs). Lastly, our results demonstrate that classical TNOs associated with the 7:4 mean motion resonance have been evolving continuously until present with non-negligible mixing of populations.

39 CFR 952.27 - Motion for reconsideration.

Science.gov (United States)

2010-07-01

... forth the points of fact and of law relied upon in support of said motion. [36 FR 11563, June 16, 1971... 39 Postal Service 1 2010-07-01 2010-07-01 false Motion for reconsideration. 952.27 Section 952.27... REPRESENTATION AND LOTTERY ORDERS § 952.27 Motion for reconsideration. A party may file a motion for...

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.)

Adaptive Motion Compensation in Radiotherapy

CERN Document Server

Murphy, Martin J

2011-01-01

External-beam radiotherapy has long been challenged by the simple fact that patients can (and do) move during the delivery of radiation. Recent advances in imaging and beam delivery technologies have made the solution--adapting delivery to natural movement--a practical reality. Adaptive Motion Compensation in Radiotherapy provides the first detailed treatment of online interventional techniques for motion compensation radiotherapy. This authoritative book discusses: Each of the contributing elements of a motion-adaptive system, including target detection and tracking, beam adaptation, and pati

Aristotle, Motion, and Rhetoric.

Science.gov (United States)

Sutton, Jane

Aristotle rejects a world vision of changing reality as neither useful nor beneficial to human life, and instead he reaffirms both change and eternal reality, fuses motion and rest, and ends up with "well-behaved" changes. This concept of motion is foundational to his world view, and from it emerges his theory of knowledge, philosophy of…

Motion Analysis Based on Invertible Rapid Transform

Directory of Open Access Journals (Sweden)

J. Turan

1999-06-01

Full Text Available This paper presents the results of a study on the use of invertible rapid transform (IRT for the motion estimation in a sequence of images. Motion estimation algorithms based on the analysis of the matrix of states (produced in the IRT calculation are described. The new method was used experimentally to estimate crowd and traffic motion from the image data sequences captured at railway stations and at high ways in large cities. The motion vectors may be used to devise a polar plot (showing velocity magnitude and direction for moving objects where the dominant motion tendency can be seen. The experimental results of comparison of the new motion estimation methods with other well known block matching methods (full search, 2D-log, method based on conventional (cross correlation (CC function or phase correlation (PC function for application of crowd motion estimation are also presented.

Live Speech Driven Head-and-Eye Motion Generators.

Science.gov (United States)

Le, Binh H; Ma, Xiaohan; Deng, Zhigang

2012-11-01

This paper describes a fully automated framework to generate realistic head motion, eye gaze, and eyelid motion simultaneously based on live (or recorded) speech input. Its central idea is to learn separate yet interrelated statistical models for each component (head motion, gaze, or eyelid motion) from a prerecorded facial motion data set: 1) Gaussian Mixture Models and gradient descent optimization algorithm are employed to generate head motion from speech features; 2) Nonlinear Dynamic Canonical Correlation Analysis model is used to synthesize eye gaze from head motion and speech features, and 3) nonnegative linear regression is used to model voluntary eye lid motion and log-normal distribution is used to describe involuntary eye blinks. Several user studies are conducted to evaluate the effectiveness of the proposed speech-driven head and eye motion generator using the well-established paired comparison methodology. Our evaluation results clearly show that this approach can significantly outperform the state-of-the-art head and eye motion generation algorithms. In addition, a novel mocap+video hybrid data acquisition technique is introduced to record high-fidelity head movement, eye gaze, and eyelid motion simultaneously.

Seismic switch for strong motion measurement

Science.gov (United States)

Harben, P.E.; Rodgers, P.W.; Ewert, D.W.

1995-05-30

A seismic switching device is described that has an input signal from an existing microseismic station seismometer and a signal from a strong motion measuring instrument. The seismic switch monitors the signal level of the strong motion instrument and passes the seismometer signal to the station data telemetry and recording systems. When the strong motion instrument signal level exceeds a user set threshold level, the seismometer signal is switched out and the strong motion signal is passed to the telemetry system. The amount of time the strong motion signal is passed before switching back to the seismometer signal is user controlled between 1 and 15 seconds. If the threshold level is exceeded during a switch time period, the length of time is extended from that instant by one user set time period. 11 figs.

On a PCA-based lung motion model

Energy Technology Data Exchange (ETDEWEB)

Li Ruijiang; Lewis, John H; Jia Xun; Jiang, Steve B [Department of Radiation Oncology and Center for Advanced Radiotherapy Technologies, University of California San Diego, 3855 Health Sciences Dr, La Jolla, CA 92037-0843 (United States); Zhao Tianyu; Wuenschel, Sara; Lamb, James; Yang Deshan; Low, Daniel A [Department of Radiation Oncology, Washington University School of Medicine, 4921 Parkview Pl, St. Louis, MO 63110-1093 (United States); Liu Weifeng, E-mail: sbjiang@ucsd.edu [Amazon.com Inc., 701 5th Ave. Seattle, WA 98104 (United States)

2011-09-21

Respiration-induced organ motion is one of the major uncertainties in lung cancer radiotherapy and is crucial to be able to accurately model the lung motion. Most work so far has focused on the study of the motion of a single point (usually the tumor center of mass), and much less work has been done to model the motion of the entire lung. Inspired by the work of Zhang et al (2007 Med. Phys. 34 4772-81), we believe that the spatiotemporal relationship of the entire lung motion can be accurately modeled based on principle component analysis (PCA) and then a sparse subset of the entire lung, such as an implanted marker, can be used to drive the motion of the entire lung (including the tumor). The goal of this work is twofold. First, we aim to understand the underlying reason why PCA is effective for modeling lung motion and find the optimal number of PCA coefficients for accurate lung motion modeling. We attempt to address the above important problems both in a theoretical framework and in the context of real clinical data. Second, we propose a new method to derive the entire lung motion using a single internal marker based on the PCA model. The main results of this work are as follows. We derived an important property which reveals the implicit regularization imposed by the PCA model. We then studied the model using two mathematical respiratory phantoms and 11 clinical 4DCT scans for eight lung cancer patients. For the mathematical phantoms with cosine and an even power (2n) of cosine motion, we proved that 2 and 2n PCA coefficients and eigenvectors will completely represent the lung motion, respectively. Moreover, for the cosine phantom, we derived the equivalence conditions for the PCA motion model and the physiological 5D lung motion model (Low et al 2005 Int. J. Radiat. Oncol. Biol. Phys. 63 921-9). For the clinical 4DCT data, we demonstrated the modeling power and generalization performance of the PCA model. The average 3D modeling error using PCA was within 1

On a PCA-based lung motion model.

Science.gov (United States)

Li, Ruijiang; Lewis, John H; Jia, Xun; Zhao, Tianyu; Liu, Weifeng; Wuenschel, Sara; Lamb, James; Yang, Deshan; Low, Daniel A; Jiang, Steve B

2011-09-21

Respiration-induced organ motion is one of the major uncertainties in lung cancer radiotherapy and is crucial to be able to accurately model the lung motion. Most work so far has focused on the study of the motion of a single point (usually the tumor center of mass), and much less work has been done to model the motion of the entire lung. Inspired by the work of Zhang et al (2007 Med. Phys. 34 4772-81), we believe that the spatiotemporal relationship of the entire lung motion can be accurately modeled based on principle component analysis (PCA) and then a sparse subset of the entire lung, such as an implanted marker, can be used to drive the motion of the entire lung (including the tumor). The goal of this work is twofold. First, we aim to understand the underlying reason why PCA is effective for modeling lung motion and find the optimal number of PCA coefficients for accurate lung motion modeling. We attempt to address the above important problems both in a theoretical framework and in the context of real clinical data. Second, we propose a new method to derive the entire lung motion using a single internal marker based on the PCA model. The main results of this work are as follows. We derived an important property which reveals the implicit regularization imposed by the PCA model. We then studied the model using two mathematical respiratory phantoms and 11 clinical 4DCT scans for eight lung cancer patients. For the mathematical phantoms with cosine and an even power (2n) of cosine motion, we proved that 2 and 2n PCA coefficients and eigenvectors will completely represent the lung motion, respectively. Moreover, for the cosine phantom, we derived the equivalence conditions for the PCA motion model and the physiological 5D lung motion model (Low et al 2005 Int. J. Radiat. Oncol. Biol. Phys. 63 921-9). For the clinical 4DCT data, we demonstrated the modeling power and generalization performance of the PCA model. The average 3D modeling error using PCA was within 1

On a PCA-based lung motion model

International Nuclear Information System (INIS)

Li Ruijiang; Lewis, John H; Jia Xun; Jiang, Steve B; Zhao Tianyu; Wuenschel, Sara; Lamb, James; Yang Deshan; Low, Daniel A; Liu Weifeng

2011-01-01

Respiration-induced organ motion is one of the major uncertainties in lung cancer radiotherapy and is crucial to be able to accurately model the lung motion. Most work so far has focused on the study of the motion of a single point (usually the tumor center of mass), and much less work has been done to model the motion of the entire lung. Inspired by the work of Zhang et al (2007 Med. Phys. 34 4772-81), we believe that the spatiotemporal relationship of the entire lung motion can be accurately modeled based on principle component analysis (PCA) and then a sparse subset of the entire lung, such as an implanted marker, can be used to drive the motion of the entire lung (including the tumor). The goal of this work is twofold. First, we aim to understand the underlying reason why PCA is effective for modeling lung motion and find the optimal number of PCA coefficients for accurate lung motion modeling. We attempt to address the above important problems both in a theoretical framework and in the context of real clinical data. Second, we propose a new method to derive the entire lung motion using a single internal marker based on the PCA model. The main results of this work are as follows. We derived an important property which reveals the implicit regularization imposed by the PCA model. We then studied the model using two mathematical respiratory phantoms and 11 clinical 4DCT scans for eight lung cancer patients. For the mathematical phantoms with cosine and an even power (2n) of cosine motion, we proved that 2 and 2n PCA coefficients and eigenvectors will completely represent the lung motion, respectively. Moreover, for the cosine phantom, we derived the equivalence conditions for the PCA motion model and the physiological 5D lung motion model (Low et al 2005 Int. J. Radiat. Oncol. Biol. Phys. 63 921-9). For the clinical 4DCT data, we demonstrated the modeling power and generalization performance of the PCA model. The average 3D modeling error using PCA was within 1

The influence of sleep deprivation and oscillating motion on sleepiness, motion sickness, and cognitive and motor performance.

Science.gov (United States)

Kaplan, Janna; Ventura, Joel; Bakshi, Avijit; Pierobon, Alberto; Lackner, James R; DiZio, Paul

2017-01-01

Our goal was to determine how sleep deprivation, nauseogenic motion, and a combination of motion and sleep deprivation affect cognitive vigilance, visual-spatial perception, motor learning and retention, and balance. We exposed four groups of subjects to different combinations of normal 8h sleep or 4h sleep for two nights combined with testing under stationary conditions or during 0.28Hz horizontal linear oscillation. On the two days following controlled sleep, all subjects underwent four test sessions per day that included evaluations of fatigue, motion sickness, vigilance, perceptual discrimination, perceptual learning, motor performance and learning, and balance. Sleep loss and exposure to linear oscillation had additive or multiplicative relationships to sleepiness, motion sickness severity, decreases in vigilance and in perceptual discrimination and learning. Sleep loss also decelerated the rate of adaptation to motion sickness over repeated sessions. Sleep loss degraded the capacity to compensate for novel robotically induced perturbations of reaching movements but did not adversely affect adaptive recovery of accurate reaching. Overall, tasks requiring substantial attention to cognitive and motor demands were degraded more than tasks that were more automatic. Our findings indicate that predicting performance needs to take into account in addition to sleep loss, the attentional demands and novelty of tasks, the motion environment in which individuals will be performing and their prior susceptibility to motion sickness during exposure to provocative motion stimulation. Copyright © 2016 Elsevier B.V. All rights reserved.

Management of respiratory motion in radiation oncology

International Nuclear Information System (INIS)

Vedam, Subrahmanya Sastry

2003-01-01

Respiration affects the instantaneous position of almost all thoracic and abdominal structures (lung, breast, liver, pancreas, etc.), posing significant problems in the radiotherapy of tumors located at these sites. The diaphragm, for example, has been shown to move approximately 1.5 cm in the superior-inferior direction during normal breathing. During radiotherapy, margin expansion around the tumor, based on an estimate of the expected range of tumor motion, is commonly employed to ensure adequate dose coverage. Such a margin estimate may or may not encompass the 'current' extent of motion exhibited by the tumor, resulting in either a higher dose to the surrounding normal tissue or a cold spot in the tumor volume, leading to poor prognosis. Accounting for respiratory motion by active management during radiotherapy can, however, potentiate a reduction in the amount of high dose to normal tissue. Active management of respiratory motion forms the primary theme of this dissertation. Among the various techniques available to manage respiratory motion, our research focused on respiratory gated and respiration synchronized radiotherapy, with an external marker to monitor respiratory motion. Multiple session recordings of diaphragm and external marker motion revealed a consistent linear relationship, validating the use of external marker motion as a 'surrogate' for diaphragm motion. The predictability of diaphragm motion based on such external marker motion both within and between treatment sessions was also determined to be of the order of 0.1 cm. Gating during exhalation was found to be more reproducible than gating during inhalation. Although, a reduction in the 'gate' width achieved a modest reduction in the margins added around the tumor further reduction was limited by setup error. A motion phantom study of the potential gains from respiratory gating indicated margin reduction of 0.2-1.1 cm while employing gating. In addition, gating also improved the quality of

Ambiguity in Tactile Apparent Motion Perception.

Directory of Open Access Journals (Sweden)

Emanuela Liaci

Full Text Available In von Schiller's Stroboscopic Alternative Motion (SAM stimulus two visually presented diagonal dot pairs, located on the corners of an imaginary rectangle, alternate with each other and induce either horizontal, vertical or, rarely, rotational motion percepts. SAM motion perception can be described by a psychometric function of the dot aspect ratio ("AR", i.e. the relation between vertical and horizontal dot distances. Further, with equal horizontal and vertical dot distances (AR = 1 perception is biased towards vertical motion. In a series of five experiments, we presented tactile SAM versions and studied the role of AR and of different reference frames for the perception of tactile apparent motion.We presented tactile SAM stimuli and varied the ARs, while participants reported the perceived motion directions. Pairs of vibration stimulators were attached to the participants' forearms and stimulator distances were varied within and between forearms. We compared straight and rotated forearm conditions with each other in order to disentangle the roles of exogenous and endogenous reference frames.Increasing the tactile SAM's AR biased perception towards vertical motion, but the effect was weak compared to the visual modality. We found no horizontal disambiguation, even for very small tactile ARs. A forearm rotation by 90° kept the vertical bias, even though it was now coupled with small ARs. A 45° rotation condition with crossed forearms, however, evoked a strong horizontal motion bias.Existing approaches to explain the visual SAM bias fail to explain the current tactile results. Particularly puzzling is the strong horizontal bias in the crossed-forearm conditions. In the case of tactile apparent motion, there seem to be no fixed priority rule for perceptual disambiguation. Rather the weighting of available evidence seems to depend on the degree of stimulus ambiguity, the current situation and on the perceptual strategy of the individual

AMD-stability in the presence of first-order mean motion resonances

Science.gov (United States)

Petit, A. C.; Laskar, J.; Boué, G.

2017-11-01

The angular momentum deficit (AMD)-stability criterion allows to discriminate between a priori stable planetary systems and systems for which the stability is not granted and needs further investigations. AMD-stability is based on the conservation of the AMD in the averaged system at all orders of averaging. While the AMD criterion is rigorous, the conservation of the AMD is only granted in absence of mean-motion resonances (MMR). Here we extend the AMD-stability criterion to take into account mean-motion resonances, and more specifically the overlap of first-order MMR. If the MMR islands overlap, the system will experience generalized chaos leading to instability. The Hamiltonian of two massive planets on coplanar quasi-circular orbits can be reduced to an integrable one degree of freedom problem for period ratios close to a first-order MMR. We use the reduced Hamiltonian to derive a new overlap criterion for first-order MMR. This stability criterion unifies the previous criteria proposed in the literature and admits the criteria obtained for initially circular and eccentric orbits as limit cases. We then improve the definition of AMD-stability to take into account the short term chaos generated by MMR overlap. We analyze the outcome of this improved definition of AMD-stability on selected multi-planet systems from the Extrasolar Planets Encyclopædia.

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

Qué es Motion Graphics

OpenAIRE

Alonso Valdivieso, Concepción

2016-01-01

[EN] What exactly are ‘Motion Graphics’? Many people still aren’t entirely sure. Taken literally they are just graphics in motion, but they also mean much more than that. Motion graphics use incredibly expressive techniques and as a result are often found in advertising, corporate videos, credit sequences, etc. They can translate a complex idea into a clear message with just a few seconds of animation.At the same time they have a very particular, simple and stylish aesthetic. But, if any anim...

Population Games, Stable Games, and Passivity

Directory of Open Access Journals (Sweden)

Michael J. Fox

2013-10-01

Full Text Available The class of “stable games”, introduced by Hofbauer and Sandholm in 2009, has the attractive property of admitting global convergence to equilibria under many evolutionary dynamics. We show that stable games can be identified as a special case of the feedback-system-theoretic notion of a “passive” dynamical system. Motivated by this observation, we develop a notion of passivity for evolutionary dynamics that complements the definition of the class of stable games. Since interconnections of passive dynamical systems exhibit stable behavior, we can make conclusions about passive evolutionary dynamics coupled with stable games. We show how established evolutionary dynamics qualify as passive dynamical systems. Moreover, we exploit the flexibility of the definition of passive dynamical systems to analyze generalizations of stable games and evolutionary dynamics that include forecasting heuristics as well as certain games with memory.

Ion Motion in the Adiabatic Focuser

International Nuclear Information System (INIS)

Henestroza, E.; Sessler, A.M.; Yu, S.S.

2006-01-01

In this paper we numerically study the effect of ion motion in an adiabatic focuser, motivated by a recent suggestion that ion motion in an adiabatic focuser might be significant and even preclude operation of the focuser as previously envisioned. It is shown that despite ion motion the adiabatic focuser should work as well as originally envisioned

Boundary singularities produced by the motion of soap films.

Science.gov (United States)

Goldstein, Raymond E; McTavish, James; Moffatt, H Keith; Pesci, Adriana I

2014-06-10

Recent work has shown that a Möbius strip soap film rendered unstable by deforming its frame changes topology to that of a disk through a "neck-pinching" boundary singularity. This behavior is unlike that of the catenoid, which transitions to two disks through a bulk singularity. It is not yet understood whether the type of singularity is generally a consequence of the surface topology, nor how this dependence could arise from an equation of motion for the surface. To address these questions we investigate experimentally, computationally, and theoretically the route to singularities of soap films with different topologies, including a family of punctured Klein bottles. We show that the location of singularities (bulk or boundary) may depend on the path of the boundary deformation. In the unstable regime the driving force for soap-film motion is the mean curvature. Thus, the narrowest part of the neck, associated with the shortest nontrivial closed geodesic of the surface, has the highest curvature and is the fastest moving. Just before onset of the instability there exists on the stable surface the shortest closed geodesic, which is the initial condition for evolution of the neck's geodesics, all of which have the same topological relationship to the frame. We make the plausible conjectures that if the initial geodesic is linked to the boundary, then the singularity will occur at the boundary, whereas if the two are unlinked initially, then the singularity will occur in the bulk. Numerical study of mean curvature flows and experiments support these conjectures.

Unconscious Local Motion Alters Global Image Speed

Science.gov (United States)

Khuu, Sieu K.; Chung, Charles Y. L.; Lord, Stephanie; Pearson, Joel

2014-01-01

Accurate motion perception of self and object speed is crucial for successful interaction in the world. The context in which we make such speed judgments has a profound effect on their accuracy. Misperceptions of motion speed caused by the context can have drastic consequences in real world situations, but they also reveal much about the underlying mechanisms of motion perception. Here we show that motion signals suppressed from awareness can warp simultaneous conscious speed perception. In Experiment 1, we measured global speed discrimination thresholds using an annulus of 8 local Gabor elements. We show that physically removing local elements from the array attenuated global speed discrimination. However, removing awareness of the local elements only had a small effect on speed discrimination. That is, unconscious local motion elements contributed to global conscious speed perception. In Experiment 2 we measured the global speed of the moving Gabor patterns, when half the elements moved at different speeds. We show that global speed averaging occurred regardless of whether local elements were removed from awareness, such that the speed of invisible elements continued to be averaged together with the visible elements to determine the global speed. These data suggest that contextual motion signals outside of awareness can both boost and affect our experience of motion speed, and suggest that such pooling of motion signals occurs before the conscious extraction of the surround motion speed. PMID:25503603

O'Connell's process as a vicious Brownian motion

International Nuclear Information System (INIS)

Katori, Makoto

2011-01-01

Vicious Brownian motion is a diffusion scaling limit of Fisher's vicious walk model, which is a system of Brownian particles in one dimension such that if two motions meet they kill each other. We consider the vicious Brownian motions conditioned never to collide with each other and call it noncolliding Brownian motion. This conditional diffusion process is equivalent to the eigenvalue process of the Hermitian-matrix-valued Brownian motion studied by Dyson [J. Math. Phys. 3, 1191 (1962)]. Recently, O'Connell [Ann. Probab. (to be published)] introduced a generalization of the noncolliding Brownian motion by using the eigenfunctions (the Whittaker functions) of the quantum Toda lattice in order to analyze a directed polymer model in 1 + 1 dimensions. We consider a system of one-dimensional Brownian motions with a long-ranged killing term as a generalization of the vicious Brownian motion and construct the O'Connell process as a conditional process of the killing Brownian motions to survive forever.

Passive infrared motion sensing technology

International Nuclear Information System (INIS)

Doctor, A.P.

1994-01-01

In the last 10 years passive IR based (8--12 microns) motion sensing has matured to become the dominant method of volumetric space protection and surveillance. These systems currently cost less than $25 to produce and yet use traditionally expensive IR optics, filters, sensors and electronic circuitry. This IR application is quite interesting in that the volumes of systems produced and the costs and performance level required prove that there is potential for large scale commercial applications of IR technology. This paper will develop the basis and principles of operation of a staring motion sensor system using a technical approach. A model for the motion of the target is developed and compared to the background. The IR power difference between the target and the background as well as the optical requirements are determined from basic principles and used to determine the performance of the system. Low cost reflective and refractive IR optics and bandpass IR filters are discussed. The pyroelectric IR detector commonly used is fully discussed and characterized. Various schemes for ''false alarms'' have been developed and are also explained. This technology is also used in passive IR based motion sensors for other applications such as lighting control. These applications are also discussed. In addition the paper will discuss new developments in IR surveillance technology such as the use of linear motion sensing arrays. This presentation can be considered a ''primer'' on the art of Passive IR Motion Sensing as applied to Surveillance Technology

Spatial filtering precedes motion detection.

Science.gov (United States)

Morgan, M J

1992-01-23

When we perceive motion on a television or cinema screen, there must be some process that allows us to track moving objects over time: if not, the result would be a conflicting mass of motion signals in all directions. A possible mechanism, suggested by studies of motion displacement in spatially random patterns, is that low-level motion detectors have a limited spatial range, which ensures that they tend to be stimulated over time by the same object. This model predicts that the direction of displacement of random patterns cannot be detected reliably above a critical absolute displacement value (Dmax) that is independent of the size or density of elements in the display. It has been inferred that Dmax is a measure of the size of motion detectors in the visual pathway. Other studies, however, have shown that Dmax increases with element size, in which case the most likely interpretation is that Dmax depends on the probability of false matches between pattern elements following a displacement. These conflicting accounts are reconciled here by showing that Dmax is indeed determined by the spacing between the elements in the pattern, but only after fine detail has been removed by a physiological prefiltering stage: the filter required to explain the data has a similar size to the receptive field of neurons in the primate magnocellular pathway. The model explains why Dmax can be increased by removing high spatial frequencies from random patterns, and simplifies our view of early motion detection.

Capturing Motion and Depth Before Cinematography.

Science.gov (United States)

Wade, Nicholas J

2016-01-01

Visual representations of biological states have traditionally faced two problems: they lacked motion and depth. Attempts were made to supply these wants over many centuries, but the major advances were made in the early-nineteenth century. Motion was synthesized by sequences of slightly different images presented in rapid succession and depth was added by presenting slightly different images to each eye. Apparent motion and depth were combined some years later, but they tended to be applied separately. The major figures in this early period were Wheatstone, Plateau, Horner, Duboscq, Claudet, and Purkinje. Others later in the century, like Marey and Muybridge, were stimulated to extend the uses to which apparent motion and photography could be applied to examining body movements. These developments occurred before the birth of cinematography, and significant insights were derived from attempts to combine motion and depth.

Precision of working memory for visual motion sequences and transparent motion surfaces.

Science.gov (United States)

Zokaei, Nahid; Gorgoraptis, Nikos; Bahrami, Bahador; Bays, Paul M; Husain, Masud

2011-12-01

Recent studies investigating working memory for location, color, and orientation support a dynamic resource model. We examined whether this might also apply to motion, using random dot kinematograms (RDKs) presented sequentially or simultaneously. Mean precision for motion direction declined as sequence length increased, with precision being lower for earlier RDKs. Two alternative models of working memory were compared specifically to distinguish between the contributions of different sources of error that corrupt memory (W. Zhang & S. J. Luck, 2008 vs. P. M. Bays, R. F. G. Catalao, & M. Husain, 2009). The latter provided a significantly better fit for the data, revealing that decrease in memory precision for earlier items is explained by an increase in interference from other items in a sequence rather than random guessing or a temporal decay of information. Misbinding feature attributes is an important source of error in working memory. Precision of memory for motion direction decreased when two RDKs were presented simultaneously as transparent surfaces, compared to sequential RDKs. However, precision was enhanced when one motion surface was prioritized, demonstrating that selective attention can improve recall precision. These results are consistent with a resource model that can be used as a general conceptual framework for understanding working memory across a range of visual features.

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.

PET Motion Compensation for Radiation Therapy Using a CT-Based Mid-Position Motion Model: Methodology and Clinical Evaluation

International Nuclear Information System (INIS)

Kruis, Matthijs F.; Kamer, Jeroen B. van de; Houweling, Antonetta C.; Sonke, Jan-Jakob; Belderbos, José S.A.; Herk, Marcel van

2013-01-01

Purpose: Four-dimensional positron emission tomography (4D PET) imaging of the thorax produces sharper images with reduced motion artifacts. Current radiation therapy planning systems, however, do not facilitate 4D plan optimization. When images are acquired in a 2-minute time slot, the signal-to-noise ratio of each 4D frame is low, compromising image quality. The purpose of this study was to implement and evaluate the construction of mid-position 3D PET scans, with motion compensated using a 4D computed tomography (CT)-derived motion model. Methods and Materials: All voxels of 4D PET were registered to the time-averaged position by using a motion model derived from the 4D CT frames. After the registration the scans were summed, resulting in a motion-compensated 3D mid-position PET scan. The method was tested with a phantom dataset as well as data from 27 lung cancer patients. Results: PET motion compensation using a CT-based motion model improved image quality of both phantoms and patients in terms of increased maximum SUV (SUV max ) values and decreased apparent volumes. In homogenous phantom data, a strong relationship was found between the amplitude-to-diameter ratio and the effects of the method. In heterogeneous patient data, the effect correlated better with the motion amplitude. In case of large amplitudes, motion compensation may increase SUV max up to 25% and reduce the diameter of the 50% SUV max volume by 10%. Conclusions: 4D CT-based motion-compensated mid-position PET scans provide improved quantitative data in terms of uptake values and volumes at the time-averaged position, thereby facilitating more accurate radiation therapy treatment planning of pulmonary lesions

Teasing Apart Complex Motions using VideoPoint

Science.gov (United States)

Fischer, Mark

2002-10-01

Using video analysis software such as VideoPoint, it is possible to explore the physics of any phenomenon that can be captured on videotape. The good news is that complex motions can be filmed and analyzed. The bad news is that the motions can become very complex very quickly. An example of such a complicated motion, the 2-dimensional motion of an object as filmed by a camera that is moving and rotating in the same plane will be discussed. Methods for extracting the desired object motion will be given as well as suggestions for shooting more easily analyzable video clips.

Improved motion description for action classification

Directory of Open Access Journals (Sweden)

Mihir eJain

2016-01-01

Full Text Available Even though the importance of explicitly integrating motion characteristics in video descriptions has been demonstrated by several recent papers on action classification, our current work concludes that adequately decomposing visual motion into dominant and residual motions, i.e.: camera and scene motion, significantly improves action recognition algorithms. This holds true both for the extraction of the space-time trajectories and for computation of descriptors.We designed a new motion descriptor – the DCS descriptor – that captures additional information on local motion patterns enhancing results based on differential motion scalar quantities, divergence, curl and shear features. Finally, applying the recent VLAD coding technique proposed in image retrieval provides a substantial improvement for action recognition. These findings are complementary to each other and they outperformed all previously reported results by a significant margin on three challenging datasets: Hollywood 2, HMDB51 and Olympic Sports as reported in (Jain et al. (2013. These results were further improved by (Oneata et al. (2013; Wang and Schmid (2013; Zhu et al. (2013 through the use of the Fisher vector encoding. We therefore also employ Fisher vector in this paper and we further enhance our approach by combining trajectories from both optical flow and compensated flow. We as well provide additional details of DCS descriptors, including visualization. For extending the evaluation, a novel dataset with 101 action classes, UCF101, was added.

Rotational Motion Control of a Spacecraft

DEFF Research Database (Denmark)

Wisniewski, Rafal; Kulczycki, P.

2001-01-01

The paper adopts the energy shaping method to control of rotational motion. A global representation of the rigid body motion is given in the canonical form by a quaternion and its conjugate momenta. A general method for motion control on a cotangent bundle to the 3-sphere is suggested. The design...... algorithm is validated for three-axis spacecraft attitude control...

Rotational motion control of a spacecraft

DEFF Research Database (Denmark)

Wisniewski, Rafal; Kulczycki, P.

2003-01-01

The paper adopts the energy shaping method to control of rotational motion. A global representation of the rigid body motion is given in the canonical form by a quaternion and its conjugate momenta. A general method for motion control on a cotangent bundle to the 3-sphere is suggested. The design...... algorithm is validated for three-axis spacecraft attitude control. Udgivelsesdato: APR...

Artificial horizon effects on motion sickness and performance.

Science.gov (United States)

Tal, Dror; Gonen, Adi; Wiener, Guy; Bar, Ronen; Gil, Amnon; Nachum, Zohar; Shupak, Avi

2012-07-01

To investigate whether the projection of Earth-referenced scenes during provocative motion can alleviate motion sickness severity and prevent motion sickness-induced degradation of performance. Exposure to unfamiliar motion patterns commonly results in motion sickness and decreased performance. Thirty subjects with moderate-to-severe motion sickness susceptibility were exposed to the recorded motion profile of a missile boat under moderate sea conditions in a 3-degrees-of-freedom ship motion simulator. During a 120-minute simulated voyage, the study participants were repeatedly put through a performance test battery and completed a motion sickness susceptibility questionnaire, while self-referenced and Earth-referenced visual scenes were projected inside the closed simulator cabin. A significant decrease was found in the maximal motion sickness severity score, from 9.83 ± 9.77 (mean ± standard deviation) to 7.23 ± 7.14 (p pitch, and heave movements of the simulator. Although there was a significant decrease in sickness severity, substantial symptoms still persisted. Decision making, vision, concentration, memory, simple reasoning, and psychomotor skills all deteriorated under the motion conditions. However, no significant differences between the projection conditions could be found in the scores of any of the performance tests. Visual information regarding the vessel's movement provided by an artificial horizon device might decrease motion sickness symptoms. However, although this device might be suitable for passive transportation, the continued deterioration in performance measures indicates that it provides no significant advantage for personnel engaged in the active operation of modern vessels.

Motion contrast using optical coherence tomography

Science.gov (United States)

Fingler, Jeffrey Paul

Diagnosis of ophthalmic diseases like age-related macular degeneration is very important for treatment of the disease as well as the development of future treatments. Optical coherence tomography (OCT) is an optical interference technique which can measure the three-dimensional structural information of the reflecting layers within a sample. In retinal imaging, OCT is used as the primary diagnostic tool for structural abnormalities such as retinal holes and detachments. The contrast within the images of this technique is based upon reflectivity changes from different regions of the retina. This thesis demonstrates the developments of methods used to produce additional contrast to the structural OCT images based on the tiny fluctuations of motion experienced by the mobile scatterers within a sample. Motion contrast was observed for motions smaller than 50 nm in images of a variety of samples. Initial contrast method demonstrations used Brownian motion differences to separate regions of a mobile Intralipid solution from a static agarose gel, chosen in concentration to minimize reflectivity contrast. Zebrafish embryos in the range of 3-4 days post fertilization were imaged using several motion contrast methods to determine the capabilities of identifying regions of vascular flow. Vasculature identification was demonstrated in zebrafish for blood vessels of all orientations as small as 10 microns in diameter. Mouse retinal imaging utilized the same motion contrast methods to determine the contrast capabilities for motions associated with vasculature within the retina. Improved contrast imaging techniques demonstrated comparable images to fluorescein angiography, the gold standard of retinal vascular imaging. Future studies can improve the demonstrated contrast analysis techniques and apply them towards human retinal motion contrast imaging for ophthalmic diagnostic purposes.

Innermost stable circular orbit of spinning particle in charged spinning black hole background

Science.gov (United States)

Zhang, Yu-Peng; Wei, Shao-Wen; Guo, Wen-Di; Sui, Tao-Tao; Liu, Yu-Xiao

2018-04-01

In this paper we investigate the innermost stable circular orbit (ISCO) (spin-aligned or anti-aligned orbit) for a classical spinning test particle with the pole-dipole approximation in the background of Kerr-Newman black hole in the equatorial plane. It is shown that the orbit of the spinning particle is related to the spin of the test particle. The motion of the spinning test particle will be superluminal if its spin is too large. We give an additional condition by considering the superluminal constraint for the ISCO in the black hole backgrounds. We obtain numerically the relations between the ISCO and the properties of the black holes and the test particle. It is found that the radius of the ISCO for a spinning test particle is smaller than that of a nonspinning test particle in the black hole backgrounds.

q-deformed Brownian motion

CERN Document Server

Man'ko, V I

1993-01-01

Brownian motion may be embedded in the Fock space of bosonic free field in one dimension.Extending this correspondence to a family of creation and annihilation operators satisfying a q-deformed algebra, the notion of q-deformation is carried from the algebra to the domain of stochastic processes.The properties of q-deformed Brownian motion, in particular its non-Gaussian nature and cumulant structure,are established.

AMUC: Associated Motion capture User Categories.

Science.gov (United States)

Norman, Sally Jane; Lawson, Sian E M; Olivier, Patrick; Watson, Paul; Chan, Anita M-A; Dade-Robertson, Martyn; Dunphy, Paul; Green, Dave; Hiden, Hugo; Hook, Jonathan; Jackson, Daniel G

2009-07-13

The AMUC (Associated Motion capture User Categories) project consisted of building a prototype sketch retrieval client for exploring motion capture archives. High-dimensional datasets reflect the dynamic process of motion capture and comprise high-rate sampled data of a performer's joint angles; in response to multiple query criteria, these data can potentially yield different kinds of information. The AMUC prototype harnesses graphic input via an electronic tablet as a query mechanism, time and position signals obtained from the sketch being mapped to the properties of data streams stored in the motion capture repository. As well as proposing a pragmatic solution for exploring motion capture datasets, the project demonstrates the conceptual value of iterative prototyping in innovative interdisciplinary design. The AMUC team was composed of live performance practitioners and theorists conversant with a variety of movement techniques, bioengineers who recorded and processed motion data for integration into the retrieval tool, and computer scientists who designed and implemented the retrieval system and server architecture, scoped for Grid-based applications. Creative input on information system design and navigation, and digital image processing, underpinned implementation of the prototype, which has undergone preliminary trials with diverse users, allowing identification of rich potential development areas.

Unusual motions of a vibrating string

Science.gov (United States)

Hanson, Roger J.

2003-10-01

The actual motions of a sinusoidally driven vibrating string can be very complex due to nonlinear effects resulting from varying tension and longitudinal motion not included in simple linear theory. Commonly observed effects are: generation of motion perpendicular to the driving force, sudden jumps in amplitude, hysteresis, and generation of higher harmonics. In addition, these effects are profoundly influenced by wire asymmetries which in a brass harpsichord wire can cause a small splitting of each natural frequency of free vibration into two closely spaced frequencies (relative separation ~0.2% to 2%), each associated with transverse motion along two orthogonal characteristic wire axes. Some unusual resulting patterns of complex motions of a point on the wire are exhibited on videotape. Examples include: sudden changes of harmonic content, generation of subharmonics, and motion which appears nearly chaotic but which has a pattern period of over 10 s. Another unusual phenomenon due to entirely different causes can occur when a violin string is bowed with a higher than normal force resulting in sounds ranging from about a musical third to a twelfth lower than the sound produced when the string is plucked.

The perception of object versus objectless motion.

Science.gov (United States)

Hock, Howard S; Nichols, David F

2013-05-01

Wertheimer, M. (Zeitschrift für Psychologie und Physiologie der Sinnesorgane, 61:161-265, 1912) classical distinction between beta (object) and phi (objectless) motion is elaborated here in a series of experiments concerning competition between two qualitatively different motion percepts, induced by sequential changes in luminance for two-dimensional geometric objects composed of rectangular surfaces. One of these percepts is of spreading-luminance motion that continuously sweeps across the entire object; it exhibits shape invariance and is perceived most strongly for fast speeds. Significantly for the characterization of phi as objectless motion, the spreading luminance does not involve surface boundaries or any other feature; the percept is driven solely by spatiotemporal changes in luminance. Alternatively, and for relatively slow speeds, a discrete series of edge motions can be perceived in the direction opposite to spreading-luminance motion. Akin to beta motion, the edges appear to move through intermediate positions within the object's changing surfaces. Significantly for the characterization of beta as object motion, edge motion exhibits shape dependence and is based on the detection of oppositely signed changes in contrast (i.e., counterchange) for features essential to the determination of an object's shape, the boundaries separating its surfaces. These results are consistent with area MT neurons that differ with respect to speed preference Newsome et al (Journal of Neurophysiology, 55:1340-1351, 1986) and shape dependence Zeki (Journal of Physiology, 236:549-573, 1974).

A system for learning statistical motion patterns.

Science.gov (United States)

Hu, Weiming; Xiao, Xuejuan; Fu, Zhouyu; Xie, Dan; Tan, Tieniu; Maybank, Steve

2006-09-01

Analysis of motion patterns is an effective approach for anomaly detection and behavior prediction. Current approaches for the analysis of motion patterns depend on known scenes, where objects move in predefined ways. It is highly desirable to automatically construct object motion patterns which reflect the knowledge of the scene. In this paper, we present a system for automatically learning motion patterns for anomaly detection and behavior prediction based on a proposed algorithm for robustly tracking multiple objects. In the tracking algorithm, foreground pixels are clustered using a fast accurate fuzzy K-means algorithm. Growing and prediction of the cluster centroids of foreground pixels ensure that each cluster centroid is associated with a moving object in the scene. In the algorithm for learning motion patterns, trajectories are clustered hierarchically using spatial and temporal information and then each motion pattern is represented with a chain of Gaussian distributions. Based on the learned statistical motion patterns, statistical methods are used to detect anomalies and predict behaviors. Our system is tested using image sequences acquired, respectively, from a crowded real traffic scene and a model traffic scene. Experimental results show the robustness of the tracking algorithm, the efficiency of the algorithm for learning motion patterns, and the encouraging performance of algorithms for anomaly detection and behavior prediction.

Force and motion

CERN Document Server

Robertson, William C

2002-01-01

Intimidated by inertia? Frightened by forces? Mystified by Newton s law of motion? You re not alone and help is at hand. The stop Faking It! Series is perfect for science teachers, home-schoolers, parents wanting to help with homework all of you who need a jargon-free way to learn the background for teaching middle school physical science with confidence. With Bill Roberton as your friendly, able but somewhat irreverent guide, you will discover you CAN come to grips with the basics of force and motion. Combining easy-to-understand explanations with activities using commonly found equipment, this book will lead you through Newton s laws to the physics of space travel. The book is as entertaining as it is informative. Best of all, the author understands the needs of adults who want concrete examples, hands-on activities, clear language, diagrams and yes, a certain amount of empathy. Ideas For Use Newton's laws, and all of the other motion principles presented in this book, do a good job of helping us to underst...

Model-Based Motion Tracking of Infants

DEFF Research Database (Denmark)

Olsen, Mikkel Damgaard; Herskind, Anna; Nielsen, Jens Bo

2014-01-01

Even though motion tracking is a widely used technique to analyze and measure human movements, only a few studies focus on motion tracking of infants. In recent years, a number of studies have emerged focusing on analyzing the motion pattern of infants, using computer vision. Most of these studies...... are based on 2D images, but few are based on 3D information. In this paper, we present a model-based approach for tracking infants in 3D. The study extends a novel study on graph-based motion tracking of infants and we show that the extension improves the tracking results. A 3D model is constructed...

Generalized quantal equation of motion

International Nuclear Information System (INIS)

Morsy, M.W.; Embaby, M.

1986-07-01

In the present paper, an attempt is made for establishing a generalized equation of motion for quantal objects, in which intrinsic self adjointness is naturally built in, independently of any prescribed representation. This is accomplished by adopting Hamilton's principle of least action, after incorporating, properly, the quantal features and employing the generalized calculus of variations, without being restricted to fixed end points representation. It turns out that our proposed equation of motion is an intrinsically self-adjoint Euler-Lagrange's differential equation that ensures extremization of the quantal action as required by Hamilton's principle. Time dependence is introduced and the corresponding equation of motion is derived, in which intrinsic self adjointness is also achieved. Reducibility of the proposed equation of motion to the conventional Schroedinger equation is examined. The corresponding continuity equation is established, and both of the probability density and the probability current density are identified. (author)

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.

DYNAMIC MAGNIFICATION OF BIOMECHANICAL SYSTEM MOTION

Directory of Open Access Journals (Sweden)

A. E. Pokatilov

2017-01-01

Full Text Available Methods for estimation of dynamic magnification pertaining to motion in biomechanics have been developed and approbаted in the paper. It has been ascertained that widely-used characteristics for evaluation of motion influence on mechanisms and machinery such as a dynamic coefficient and acceleration capacity factor become irrelevant while investigating human locomotion under elastic support conditions. The reason is an impossibility to compare human motion in case when there is a contact with elastic and rigid supports because while changing rigidity of the support exercise performing technique is also changing. In this case the technique still depends on a current state of a specific sportsman. Such situation is observed in sports gymnastics. Structure of kinematic and dynamic models for human motion has been investigated in the paper. It has been established that properties of an elastic support are reflected in models within two aspects: in an explicit form, when models have parameters of dynamic deformation for a gymnastic apparatus, and in an implicit form, when we have numerically changed parameters of human motion. The first part can be evaluated quantitatively while making comparison with calculations made in accordance with complete models. For this reason notions of selected and complete models have been introduced in the paper. It has been proposed to specify models for support and models of biomechanical system that represent models pertaining only to human locomotor system. It has been revealed that the selected models of support in kinematics and dynamics have structural difference. Kinematics specifies only parameters of elastic support deformation and dynamics specifies support parameters in an explicit form and additionally in models of human motion in an explicit form as well. Quantitative estimation of a dynamic motion magnification in kinematics and dynamics models has been given while using computing experiment for grand

S4-3: Spatial Processing of Visual Motion

Directory of Open Access Journals (Sweden)

Shin'ya Nishida

2012-10-01

Full Text Available Local motion signals are extracted in parallel by a bank of motion detectors, and their spatiotemporal interactions are processed in subsequent stages. In this talk, I will review our recent studies on spatial interactions in visual motion processing. First, we found two types of spatial pooling of local motion signals. Directionally ambiguous 1D local motion signals are pooled across orientation and space for solution of the aperture problem, while 2D local motion signals are pooled for estimation of global vector average (e.g., Amano et al., 2009 Journal of Vision 9(3:4 1–25. Second, when stimulus presentation is brief, coherent motion detection of dynamic random-dot kinematogram is not efficient. Nevertheless, it is significantly improved by transient and synchronous presentation of a stationary surround pattern. This suggests that centre-surround spatial interaction may help rapid perception of motion (Linares et al., submitted. Third, to know how the visual system encodes pairwise relationships between remote motion signals, we measured the temporal rate limit for perceiving the relationship of two motion directions presented at the same time at different spatial locations. Compared with similar tasks with luminance or orientation signals, motion comparison was more rapid and hence efficient. This high performance was affected little by inter-element separation even when it was increased up to 100 deg. These findings indicate the existence of specialized processes to encode long-range relationships between motion signals for quick appreciation of global dynamic scene structure (Maruya et al., in preparation.

Example-Based Automatic Music-Driven Conventional Dance Motion Synthesis

Energy Technology Data Exchange (ETDEWEB)

Xu, Songhua [ORNL; Fan, Rukun [University of North Carolina, Chapel Hill; Geng, Weidong [Zhejiang University

2011-04-21

We introduce a novel method for synthesizing dance motions that follow the emotions and contents of a piece of music. Our method employs a learning-based approach to model the music to motion mapping relationship embodied in example dance motions along with those motions' accompanying background music. A key step in our method is to train a music to motion matching quality rating function through learning the music to motion mapping relationship exhibited in synchronized music and dance motion data, which were captured from professional human dance performance. To generate an optimal sequence of dance motion segments to match with a piece of music, we introduce a constraint-based dynamic programming procedure. This procedure considers both music to motion matching quality and visual smoothness of a resultant dance motion sequence. We also introduce a two-way evaluation strategy, coupled with a GPU-based implementation, through which we can execute the dynamic programming process in parallel, resulting in significant speedup. To evaluate the effectiveness of our method, we quantitatively compare the dance motions synthesized by our method with motion synthesis results by several peer methods using the motions captured from professional human dancers' performance as the gold standard. We also conducted several medium-scale user studies to explore how perceptually our dance motion synthesis method can outperform existing methods in synthesizing dance motions to match with a piece of music. These user studies produced very positive results on our music-driven dance motion synthesis experiments for several Asian dance genres, confirming the advantages of our method.

Example-based automatic music-driven conventional dance motion synthesis.

Science.gov (United States)

Fan, Rukun; Xu, Songhua; Geng, Weidong

2012-03-01

We introduce a novel method for synthesizing dance motions that follow the emotions and contents of a piece of music. Our method employs a learning-based approach to model the music to motion mapping relationship embodied in example dance motions along with those motions' accompanying background music. A key step in our method is to train a music to motion matching quality rating function through learning the music to motion mapping relationship exhibited in synchronized music and dance motion data, which were captured from professional human dance performance. To generate an optimal sequence of dance motion segments to match with a piece of music, we introduce a constraint-based dynamic programming procedure. This procedure considers both music to motion matching quality and visual smoothness of a resultant dance motion sequence. We also introduce a two-way evaluation strategy, coupled with a GPU-based implementation, through which we can execute the dynamic programming process in parallel, resulting in significant speedup. To evaluate the effectiveness of our method, we quantitatively compare the dance motions synthesized by our method with motion synthesis results by several peer methods using the motions captured from professional human dancers' performance as the gold standard. We also conducted several medium-scale user studies to explore how perceptually our dance motion synthesis method can outperform existing methods in synthesizing dance motions to match with a piece of music. These user studies produced very positive results on our music-driven dance motion synthesis experiments for several Asian dance genres, confirming the advantages of our method.

3D motion analysis via energy minimization

Energy Technology Data Exchange (ETDEWEB)

Wedel, Andreas

2009-10-16

This work deals with 3D motion analysis from stereo image sequences for driver assistance systems. It consists of two parts: the estimation of motion from the image data and the segmentation of moving objects in the input images. The content can be summarized with the technical term machine visual kinesthesia, the sensation or perception and cognition of motion. In the first three chapters, the importance of motion information is discussed for driver assistance systems, for machine vision in general, and for the estimation of ego motion. The next two chapters delineate on motion perception, analyzing the apparent movement of pixels in image sequences for both a monocular and binocular camera setup. Then, the obtained motion information is used to segment moving objects in the input video. Thus, one can clearly identify the thread from analyzing the input images to describing the input images by means of stationary and moving objects. Finally, I present possibilities for future applications based on the contents of this thesis. Previous work in each case is presented in the respective chapters. Although the overarching issue of motion estimation from image sequences is related to practice, there is nothing as practical as a good theory (Kurt Lewin). Several problems in computer vision are formulated as intricate energy minimization problems. In this thesis, motion analysis in image sequences is thoroughly investigated, showing that splitting an original complex problem into simplified sub-problems yields improved accuracy, increased robustness, and a clear and accessible approach to state-of-the-art motion estimation techniques. In Chapter 4, optical flow is considered. Optical flow is commonly estimated by minimizing the combined energy, consisting of a data term and a smoothness term. These two parts are decoupled, yielding a novel and iterative approach to optical flow. The derived Refinement Optical Flow framework is a clear and straight-forward approach to

Analysis of Human's Motions Based on Local Mean Decomposition in Through-wall Radar Detection

Science.gov (United States)

Lu, Qi; Liu, Cai; Zeng, Zhaofa; Li, Jing; Zhang, Xuebing

2016-04-01

Observation of human motions through a wall is an important issue in security applications and search-and rescue. Radar has advantages in looking through walls where other sensors give low performance or cannot be used at all. Ultrawideband (UWB) radar has high spatial resolution as a result of employment of ultranarrow pulses. It has abilities to distinguish the closely positioned targets and provide time-lapse information of targets. Moreover, the UWB radar shows good performance in wall penetration when the inherently short pulses spread their energy over a broad frequency range. Human's motions show periodic features including respiration, swing arms and legs, fluctuations of the torso. Detection of human targets is based on the fact that there is always periodic motion due to breathing or other body movements like walking. The radar can gain the reflections from each human body parts and add the reflections at each time sample. The periodic movements will cause micro-Doppler modulation in the reflected radar signals. Time-frequency analysis methods are consider as the effective tools to analysis and extract micro-Doppler effects caused by the periodic movements in the reflected radar signal, such as short-time Fourier transform (STFT), wavelet transform (WT), and Hilbert-Huang transform (HHT).The local mean decomposition (LMD), initially developed by Smith (2005), is to decomposed amplitude and frequency modulated signals into a small set of product functions (PFs), each of which is the product of an envelope signal and a frequency modulated signal from which a time-vary instantaneous phase and instantaneous frequency can be derived. As bypassing the Hilbert transform, the LMD has no demodulation error coming from window effect and involves no negative frequency without physical sense. Also, the instantaneous attributes obtained by LMD are more stable and precise than those obtained by the empirical mode decomposition (EMD) because LMD uses smoothed local

Rolling motion in moving droplets

Indian Academy of Sciences (India)

motions. The two limits of a thin sheet-like drop in sliding motion on a surface, and a spherical drop in roll, have been extensively .... rigid body rotation. The solid body rotation makes sense in the context of small Reynolds. (Re) number flows ...

Dominance of free wall radial motion in global right ventricular function of heart transplant recipients.

Science.gov (United States)

Lakatos, Bálint Károly; Tokodi, Márton; Assabiny, Alexandra; Tősér, Zoltán; Kosztin, Annamária; Doronina, Alexandra; Rácz, Kristóf; Koritsánszky, Kinga Bianka; Berzsenyi, Viktor; Németh, Endre; Sax, Balázs; Kovács, Attila; Merkely, Béla

2018-03-01

Assessment of right ventricular (RV) function using conventional echocardiography might be inadequate as the radial motion of the RV free wall is often neglected. Our aim was to quantify the longitudinal and the radial components of RV function using three-dimensional (3D) echocardiography in heart transplant (HTX) recipients. Fifty-one HTX patients in stable cardiovascular condition without history of relevant rejection episode or chronic allograft vasculopathy and 30 healthy volunteers were enrolled. RV end-diastolic (EDV) volume and total ejection fraction (TEF) were measured by 3D echocardiography. Furthermore, we quantified longitudinal (LEF) and radial ejection fraction (REF) by decomposing the motion of the RV using the ReVISION method. RV EDV did not differ between groups (HTX vs control; 96 ± 27 vs 97 ± 2 mL). In HTX patients, TEF was lower, however, tricuspid annular plane systolic excursion (TAPSE) decreased to a greater extent (TEF: 47 ± 7 vs 54 ± 4% [-13%], TAPSE: 11 ± 5 vs 21 ± 4 mm [-48%], P < .0001). In HTX patients, REF/TEF ratio was significantly higher compared to LEF/TEF (REF/TEF vs LEF/TEF: 0.58 ± 0.10 vs 0.27 ± 0.08, P < .0001), while in controls the REF/TEF and LEF/TEF ratio was similar (0.45 ± 0.07 vs 0.47 ± 0.07). Current results confirm the superiority of radial motion in determining RV function in HTX patients. Parameters incorporating the radial motion are recommended to assess RV function in HTX recipients. © 2018 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Motion sickness, stress and the endocannabinoid system.

Directory of Open Access Journals (Sweden)

Alexander Choukèr

Full Text Available BACKGROUND: A substantial number of individuals are at risk for the development of motion sickness induced nausea and vomiting (N&V during road, air or sea travel. Motion sickness can be extremely stressful but the neurobiologic mechanisms leading to motion sickness are not clear. The endocannabinoid system (ECS represents an important neuromodulator of stress and N&V. Inhibitory effects of the ECS on N&V are mediated by endocannabinoid-receptor activation. METHODOLOGY/PRINCIPAL FINDINGS: We studied the activity of the ECS in human volunteers (n = 21 during parabolic flight maneuvers (PFs. During PFs, microgravity conditions (<10(-2 g are generated for approximately 22 s which results in a profound kinetic stimulus. Blood endocannabinoids (anandamide and 2-arachidonoylglycerol, 2-AG were measured from blood samples taken in-flight before start of the parabolic maneuvers, after 10, 20, and 30 parabolas, in-flight after termination of PFs and 24 h later. Volunteers who developed acute motion sickness (n = 7 showed significantly higher stress scores but lower endocannabinoid levels during PFs. After 20 parabolas, blood anandamide levels had dropped significantly in volunteers with motion sickness (from 0.39+/-0.40 to 0.22+/-0.25 ng/ml but increased in participants without the condition (from 0.43+/-0.23 to 0.60+/-0.38 ng/ml resulting in significantly higher anandamide levels in participants without motion sickness (p = 0.02. 2-AG levels in individuals with motion sickness were low and almost unchanged throughout the experiment but showed a robust increase in participants without motion sickness. Cannabinoid-receptor 1 (CB1 but not cannabinoid-receptor 2 (CB2 mRNA expression in leucocytes 4 h after the experiment was significantly lower in volunteers with motion sickness than in participants without N&V. CONCLUSIONS/SIGNIFICANCE: These findings demonstrate that stress and motion sickness in humans are associated with impaired endocannabinoid

Driven motion of vortices in superconductors

International Nuclear Information System (INIS)

Crabtree, G.W.; Leaf, G.K.; Kaper, H.G.; Vinokur, V.M.; Koshelev, A.E.; Braun, D.W.; Levine, D.M.

1995-09-01

The driven motion of vortices in the solid vortex state is analyzed with the time-dependent Ginzburg-Landau equations. In large-scale numerical simulations, carried out on the IBM Scalable POWERparallel (SP) system at Argonne National Laboratory, many hundreds of vortices are followed as they move under the influence of a Lorentz force induced by a transport current in the presence of a planar defect (similar to a twin boundary in YBa 2 CU 3 O 7 ). Correlations in the positions and velocities of the vortices in plastic and elastic motion are identified and compared. Two types of plastic motion are observed. Organized plastic motion displaying long-range orientational correlation and shorter-range velocity correlation occurs when the driving forces are small compared to the pinning forces in the twin boundary. Disorganized plastic motion displaying no significant correlation in either the velocities or orientation of the vortex system occurs when the driving and pinning forces axe of the same order

Proper motions and distances of quasars

International Nuclear Information System (INIS)

Varshni, Y.P.

1982-01-01

The author's theory that quasars are stars raises the question of their proper motions. From the evidence presented in a previous paper, it is hypothesised that planetary nuclei and quasars are related objects and that their distributions in the galaxy are not very different. Proper motions of 30 quasars, calculated from existing measurements, are discussed. It is shown that three of these, namely PHL 1033, LB 8956 and LB 8991, have proper motions comparable to the largest proper motion known amongst the planetary nuclei. From this it is estimated that these three quasars lie within a few hundred parsecs from the sun. The evidence presented in a previous paper and the present one clearly supports the theory that quasars are stars. The possibility of using the interstellar K and H lines as distance indicators of quasars is discussed and the available evidence summarised. The desirability of determining more accurate values of the proper motions of quasars is emphasised. (Auth.)

Clustering Of Left Ventricular Wall Motion Patterns

Science.gov (United States)

Bjelogrlic, Z.; Jakopin, J.; Gyergyek, L.

1982-11-01

A method for detection of wall regions with similar motion was presented. A model based on local direction information was used to measure the left ventricular wall motion from cineangiographic sequence. Three time functions were used to define segmental motion patterns: distance of a ventricular contour segment from the mean contour, the velocity of a segment and its acceleration. Motion patterns were clustered by the UPGMA algorithm and by an algorithm based on K-nearest neighboor classification rule.

Confirmation, refinement, and extension of a study in intrafraction motion interplay with sliding jaw motion

International Nuclear Information System (INIS)

Kissick, Michael W.; Boswell, Sarah A.; Jeraj, Robert; Mackie, T. Rockwell

2005-01-01

The interplay between a constant scan speed and intrafraction oscillatory motion produces interesting fluence intensity modulations along the axis of motion that are sensitive to the motion function, as originally shown in a classic paper by Yu et al. [Phys. Med. Biol. 43, 91-104 (1998)]. The fluence intensity profiles are explored in this note for an intuitive understanding, then compared with Yu et al., and finally further explored for the effects of low scan speed and random components of both intrafraction and interfraction motion. At slow scan speeds typical of helical tomotherapy, these fluence intensity modulations are only a few percent. With the addition of only a small amount of cycle-to-cycle randomness in frequency and amplitude, the fluence intensity profiles change dramatically. It is further shown that after a typical 30-fraction treatment, the sensitivities displayed in the single fraction fluence intensity profiles greatly diminish

Sustained attention to objects' motion sharpens position representations: Attention to changing position and attention to motion are distinct.

Science.gov (United States)

Howard, Christina J; Rollings, Victoria; Hardie, Amy

2017-06-01

In tasks where people monitor moving objects, such the multiple object tracking task (MOT), observers attempt to keep track of targets as they move amongst distracters. The literature is mixed as to whether observers make use of motion information to facilitate performance. We sought to address this by two means: first by superimposing arrows on objects which varied in their informativeness about motion direction and second by asking observers to attend to motion direction. Using a position monitoring task, we calculated mean error magnitudes as a measure of the precision with which target positions are represented. We also calculated perceptual lags versus extrapolated reports, which are the times at which positions of targets best match position reports. We find that the presence of motion information in the form of superimposed arrows made no difference to position report precision nor perceptual lag. However, when we explicitly instructed observers to attend to motion, we saw facilitatory effects on position reports and in some cases reports that best matched extrapolated rather than lagging positions for small set sizes. The results indicate that attention to changing positions does not automatically recruit attention to motion, showing a dissociation between sustained attention to changing positions and attention to motion. Copyright © 2017 Elsevier Ltd. All rights reserved.

Utilize target motion to cover clinical target volume (ctv) - a novel and practical treatment planning approach to manage respiratory motion

International Nuclear Information System (INIS)

Jin Jianyue; Ajlouni, Munther; Kong Fengming; Ryu, Samuel; Chetty, Indrin J.; Movsas, Benjamin

2008-01-01

Purpose: To use probability density function (PDF) to model motion effects and incorporate this information into treatment planning for lung cancers. Material and methods: PDFs were calculated from the respiratory motion traces of 10 patients. Motion effects were evaluated by convolving static dose distributions with various PDFs. Based on a differential dose prescription with relatively lower dose to the clinical target volume (CTV) than to the gross tumor volume (GTV), two approaches were proposed to incorporate PDFs into treatment planning. The first approach uses the GTV-based internal target volume (ITV) as the planning target volume (PTV) to ensure full dose to the GTV, and utilizes the motion-induced dose gradient to cover the CTV. The second approach employs an inhomogeneous static dose distribution within a minimized PTV to best match the prescription dose gradient. Results: Motion effects on dose distributions were minimal in the anterior-posterior (AP) and lateral directions: a 10-mm motion only induced about 3% of dose reduction in the peripheral target region. The motion effect was remarkable in the cranial-caudal direction. It varied with the motion amplitude, but tended to be similar for various respiratory patterns. For the first approach, a 10-15 mm motion would adequately cover the CTV (presumed to be 60-70% of the GTV dose) without employing the CTV in planning. For motions 15-mm. An example of inhomogeneous static dose distribution in a reduced PTV was given, and it showed significant dose reduction in the normal tissue without compromising target coverage. Conclusions: Respiratory motion-induced dose gradient can be utilized to cover the CTV and minimize the lung dose without the need for more sophisticated technologies

Trend-Centric Motion Visualization: Designing and Applying a New Strategy for Analyzing Scientific Motion Collections.

Science.gov (United States)

Schroeder, David; Korsakov, Fedor; Knipe, Carissa Mai-Ping; Thorson, Lauren; Ellingson, Arin M; Nuckley, David; Carlis, John; Keefe, Daniel F

2014-12-01

In biomechanics studies, researchers collect, via experiments or simulations, datasets with hundreds or thousands of trials, each describing the same type of motion (e.g., a neck flexion-extension exercise) but under different conditions (e.g., different patients, different disease states, pre- and post-treatment). Analyzing similarities and differences across all of the trials in these collections is a major challenge. Visualizing a single trial at a time does not work, and the typical alternative of juxtaposing multiple trials in a single visual display leads to complex, difficult-to-interpret visualizations. We address this problem via a new strategy that organizes the analysis around motion trends rather than trials. This new strategy matches the cognitive approach that scientists would like to take when analyzing motion collections. We introduce several technical innovations making trend-centric motion visualization possible. First, an algorithm detects a motion collection's trends via time-dependent clustering. Second, a 2D graphical technique visualizes how trials leave and join trends. Third, a 3D graphical technique, using a median 3D motion plus a visual variance indicator, visualizes the biomechanics of the set of trials within each trend. These innovations are combined to create an interactive exploratory visualization tool, which we designed through an iterative process in collaboration with both domain scientists and a traditionally-trained graphic designer. We report on insights generated during this design process and demonstrate the tool's effectiveness via a validation study with synthetic data and feedback from expert musculoskeletal biomechanics researchers who used the tool to analyze the effects of disc degeneration on human spinal kinematics.

Motion simulator with exchangeable unit

NARCIS (Netherlands)

Mulder, J.A.; Beukers, A.; Baarspul, M.; Van Tooren, M.J.; De Winter, S.E.E.

2001-01-01

A motion simulator provided with a movable housing, preferably carried by a number of length-adjustable legs, in which housing projection means are arranged for visual information supply, while in the housing a control environment of a motion apparatus to be simulated is situated, the control

Study on characteristics of vertical strong motions

International Nuclear Information System (INIS)

Akao, Y.; Katukura, H.; Fukushima, S.; Mizutani, M.

1993-01-01

Statistic properties of vertical strong ground motions from near-field earthquakes are discussed in comparison with that of horizontal motions. It is a feature of this analysis that time history of each observed record is divided into direct P- and S-wave segments from a seismological viewpoint. Following results are obtained. Vertical motion energy excited by direct S-waves is about 0.6 times of horizontal ones at deep underground, and it approaches to 1.0 at shallow place. Horizontal motion energy excited by direct P-waves becomes 0.2 times (at deep) or more (at shallow) of vertical one. These results can be available in modeling of input motions for aseismic design. (author)

Dance notations and robot motion

CERN Document Server

Abe, Naoko

2016-01-01

How and why to write a movement? Who is the writer? Who is the reader? They may be choreographers working with dancers. They may be roboticists programming robots. They may be artists designing cartoons in computer animation. In all such fields the purpose is to express an intention about a dance, a specific motion or an action to perform, in terms of intelligible sequences of elementary movements, as a music score that would be devoted to motion representation. Unfortunately there is no universal language to write a motion. Motion languages live together in a Babel tower populated by biomechanists, dance notators, neuroscientists, computer scientists, choreographers, roboticists. Each community handles its own concepts and speaks its own language. The book accounts for this diversity. Its origin is a unique workshop held at LAAS-CNRS in Toulouse in 2014. Worldwide representatives of various communities met there. Their challenge was to reach a mutual understanding allowing a choreographer to access robotics ...

Ground-motion prediction from tremor

Science.gov (United States)

Baltay, Annemarie S.; Beroza, Gregory C.

2013-01-01

The widespread occurrence of tremor, coupled with its frequency content and location, provides an exceptional opportunity to test and improve strong ground-motion attenuation relations for subduction zones. We characterize the amplitude of thousands of individual 5 min tremor events in Cascadia during three episodic tremor and slip events to constrain the distance decay of peak ground acceleration (PGA) and peak ground velocity (PGV). We determine the anelastic attenuation parameter for ground-motion prediction equations (GMPEs) to a distance of 150 km, which is sufficient to place important constraints on ground-motion decay. Tremor PGA and PGV show a distance decay that is similar to subduction-zone-specific GMPEs developed from both data and simulations; however, the massive amount of data present in the tremor observations should allow us to refine distance-amplitude attenuation relationships for use in hazard maps, and to search for regional variations and intrasubduction zone differences in ground-motion attenuation.

Iterative CT reconstruction with correction for known rigid motion

Energy Technology Data Exchange (ETDEWEB)

Nuyts, Johan [Katholieke Univ. Leuven (Belgium). Dept. of Nuclear Medicine; Kim, Jung-Ha; Fulton, Roger [Sydney Univ., NSW (Australia). School of Physics; Westmead Hospital, Sydney (Australia). Medical Physics

2011-07-01

In PET/CT brain imaging, correction for motion may be needed, in particular for children and psychiatric patients. Motion is more likely to occur in the lengthy PET measurement, but also during the short CT acquisition patient motion is possible. Rigid motion of the head can be measured independently from the PET/CT system with optical devices. In this paper, we propose a method and some preliminary simulation results for iterative CT reconstruction with correction for known rigid motion. We implemented an iterative algorithm for fully 3D reconstruction from helical CT scans. The motion of the head is incorporated in the system matrix as a view-dependent motion of the CT-system. The first simulation results indicate that some motion patterns may produce loss of essential data. This loss precludes exact reconstruction and results in artifacts in the reconstruction, even when motion is taken into account. However, by reducing the pitch during acquisition, the same motion pattern no longer caused artifacts in the motion corrected image. (orig.)

Stable particles

International Nuclear Information System (INIS)

Samios, N.P.

1993-01-01

I have been asked to review the subject of stable particles, essentially the particles that eventually comprised the meson and baryon octets. with a few more additions -- with an emphasis on the contributions made by experiments utilizing the bubble chamber technique. In this activity, much work had been done by the photographic emulsion technique and cloud chambers-exposed to cosmic rays as well as accelerator based beams. In fact, many if not most of the stable particles were found by these latter two techniques, however, the forte of the bubble chamber (coupled with the newer and more powerful accelerators) was to verify, and reinforce with large statistics, the existence of these states, to find some of the more difficult ones, mainly neutrals and further to elucidate their properties, i.e., spin, parity, lifetimes, decay parameters, etc

Motion artifacts in functional near-infrared spectroscopy: a comparison of motion correction techniques applied to real cognitive data

Science.gov (United States)

Brigadoi, Sabrina; Ceccherini, Lisa; Cutini, Simone; Scarpa, Fabio; Scatturin, Pietro; Selb, Juliette; Gagnon, Louis; Boas, David A.; Cooper, Robert J.

2013-01-01

Motion artifacts are a significant source of noise in many functional near-infrared spectroscopy (fNIRS) experiments. Despite this, there is no well-established method for their removal. Instead, functional trials of fNIRS data containing a motion artifact are often rejected completely. However, in most experimental circumstances the number of trials is limited, and multiple motion artifacts are common, particularly in challenging populations. Many methods have been proposed recently to correct for motion artifacts, including principle component analysis, spline interpolation, Kalman filtering, wavelet filtering and correlation-based signal improvement. The performance of different techniques has been often compared in simulations, but only rarely has it been assessed on real functional data. Here, we compare the performance of these motion correction techniques on real functional data acquired during a cognitive task, which required the participant to speak aloud, leading to a low-frequency, low-amplitude motion artifact that is correlated with the hemodynamic response. To compare the efficacy of these methods, objective metrics related to the physiology of the hemodynamic response have been derived. Our results show that it is always better to correct for motion artifacts than reject trials, and that wavelet filtering is the most effective approach to correcting this type of artifact, reducing the area under the curve where the artifact is present in 93% of the cases. Our results therefore support previous studies that have shown wavelet filtering to be the most promising and powerful technique for the correction of motion artifacts in fNIRS data. The analyses performed here can serve as a guide for others to objectively test the impact of different motion correction algorithms and therefore select the most appropriate for the analysis of their own fNIRS experiment. PMID:23639260

17 CFR 10.26 - Motions and other papers.

Science.gov (United States)

2010-04-01

... 17 Commodity and Securities Exchanges 1 2010-04-01 2010-04-01 false Motions and other papers. 10... PRACTICE Institution of Adjudica- tory Proceedings; Pleadings; Motions § 10.26 Motions and other papers. (a...) the authority relied upon. If a motion is supported by briefs, affidavits or other papers, they shall...

Influence of horse stable environment on human airways

Directory of Open Access Journals (Sweden)

Pringle John

2009-05-01

Full Text Available Abstract Background Many people spend considerable amount of time each day in equine stable environments either as employees in the care and training of horses or in leisure activity. However, there are few studies available on how the stable environment affects human airways. This study examined in one horse stable qualitative differences in indoor air during winter and late summer conditions and assessed whether air quality was associated with clinically detectable respiratory signs or alterations to selected biomarkers of inflammation and lung function in stable personnel. Methods The horse stable environment and stable-workers (n = 13 in one stable were investigated three times; first in the winter, second in the interjacent late summer and the third time in the following winter stabling period. The stable measurements included levels of ammonia, hydrogen sulphide, total and respirable dust, airborne horse allergen, microorganisms, endotoxin and glucan. The stable-workers completed a questionnaire on respiratory symptoms, underwent nasal lavage with subsequent analysis of inflammation markers, and performed repeated measurements of pulmonary function. Results Measurements in the horse stable showed low organic dust levels and high horse allergen levels. Increased viable level of fungi in the air indicated a growing source in the stable. Air particle load as well as 1,3-β-glucan was higher at the two winter time-points, whereas endotoxin levels were higher at the summer time-point. Two stable-workers showed signs of bronchial obstruction with increased PEF-variability, increased inflammation biomarkers relating to reported allergy, cold or smoking and reported partly work-related symptoms. Furthermore, two other stable-workers reported work-related airway symptoms, of which one had doctor's diagnosed asthma which was well treated. Conclusion Biomarkers involved in the development of airway diseases have been studied in relation to

Influence of horse stable environment on human airways.

Science.gov (United States)

Elfman, Lena; Riihimäki, Miia; Pringle, John; Wålinder, Robert

2009-05-25

Many people spend considerable amount of time each day in equine stable environments either as employees in the care and training of horses or in leisure activity. However, there are few studies available on how the stable environment affects human airways. This study examined in one horse stable qualitative differences in indoor air during winter and late summer conditions and assessed whether air quality was associated with clinically detectable respiratory signs or alterations to selected biomarkers of inflammation and lung function in stable personnel. The horse stable environment and stable-workers (n = 13) in one stable were investigated three times; first in the winter, second in the interjacent late summer and the third time in the following winter stabling period. The stable measurements included levels of ammonia, hydrogen sulphide, total and respirable dust, airborne horse allergen, microorganisms, endotoxin and glucan. The stable-workers completed a questionnaire on respiratory symptoms, underwent nasal lavage with subsequent analysis of inflammation markers, and performed repeated measurements of pulmonary function. Measurements in the horse stable showed low organic dust levels and high horse allergen levels. Increased viable level of fungi in the air indicated a growing source in the stable. Air particle load as well as 1,3-beta-glucan was higher at the two winter time-points, whereas endotoxin levels were higher at the summer time-point. Two stable-workers showed signs of bronchial obstruction with increased PEF-variability, increased inflammation biomarkers relating to reported allergy, cold or smoking and reported partly work-related symptoms. Furthermore, two other stable-workers reported work-related airway symptoms, of which one had doctor's diagnosed asthma which was well treated. Biomarkers involved in the development of airway diseases have been studied in relation to environmental exposure levels in equine stables. Respirable dust and 1

Stable configurations in social networks

Science.gov (United States)

Bronski, Jared C.; DeVille, Lee; Ferguson, Timothy; Livesay, Michael

2018-06-01

We present and analyze a model of opinion formation on an arbitrary network whose dynamics comes from a global energy function. We study the global and local minimizers of this energy, which we call stable opinion configurations, and describe the global minimizers under certain assumptions on the friendship graph. We show a surprising result that the number of stable configurations is not necessarily monotone in the strength of connection in the social network, i.e. the model sometimes supports more stable configurations when the interpersonal connections are made stronger.

Development of Stable Isotope Technology

International Nuclear Information System (INIS)

Jeong, Do Young; Kim, Cheol Jung; Han, Jae Min

2009-03-01

KAERI has obtained an advanced technology with singular originality for laser stable isotope separation. Objectives for this project are to get production technology of Tl-203 stable isotope used for medical application and are to establish the foundation of the pilot system, while we are taking aim at 'Laser Isotope Separation Technology to make resistance to the nuclear proliferation'. And we will contribute to ensuring a nuclear transparency in the world society by taking part in a practical group of NSG and being collaboration with various international groups related to stable isotope separation technology

10 CFR 820.39 - Motions.

Science.gov (United States)

2010-01-01

... an enforcement adjudication except those made orally, shall be in writing, state the grounds therefor..., certificate, other evidence, or legal memorandum relied upon. (b) Answer to motions. Except as otherwise... to file a written answer to the motion of another party within 10 days after the filing of such...

Symmetries and conserved quantities in geodesic motion

International Nuclear Information System (INIS)

Hojman, S.; Nunez, L.; Patino, A.; Rago, H.

1986-01-01

Recently obtained results linking several constants of motion to one (non-Noetherian) symmetry to the problem of geodesic motion in Riemannian space-times are applied. The construction of conserved quantities in geodesic motion as well as the deduction of geometrical statements about Riemannian space-times are achieved

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...

Calcium stable isotope geochemistry

Energy Technology Data Exchange (ETDEWEB)

Gausonne, Nikolaus [Muenster Univ. (Germany). Inst. fuer Mineralogie; Schmitt, Anne-Desiree [Strasbourg Univ. (France). LHyGeS/EOST; Heuser, Alexander [Bonn Univ. (Germany). Steinmann-Inst. fuer Geologie, Mineralogie und Palaeontologie; Wombacher, Frank [Koeln Univ. (Germany). Inst. fuer Geologie und Mineralogie; Dietzel, Martin [Technische Univ. Graz (Austria). Inst. fuer Angewandte Geowissenschaften; Tipper, Edward [Cambridge Univ. (United Kingdom). Dept. of Earth Sciences; Schiller, Martin [Copenhagen Univ. (Denmark). Natural History Museum of Denmark

2016-08-01

This book provides an overview of the fundamentals and reference values for Ca stable isotope research, as well as current analytical methodologies including detailed instructions for sample preparation and isotope analysis. As such, it introduces readers to the different fields of application, including low-temperature mineral precipitation and biomineralisation, Earth surface processes and global cycling, high-temperature processes and cosmochemistry, and lastly human studies and biomedical applications. The current state of the art in these major areas is discussed, and open questions and possible future directions are identified. In terms of its depth and coverage, the current work extends and complements the previous reviews of Ca stable isotope geochemistry, addressing the needs of graduate students and advanced researchers who want to familiarize themselves with Ca stable isotope research.

Calcium stable isotope geochemistry

International Nuclear Information System (INIS)

Gausonne, Nikolaus; Schmitt, Anne-Desiree; Heuser, Alexander; Wombacher, Frank; Dietzel, Martin; Tipper, Edward; Schiller, Martin

2016-01-01

This book provides an overview of the fundamentals and reference values for Ca stable isotope research, as well as current analytical methodologies including detailed instructions for sample preparation and isotope analysis. As such, it introduces readers to the different fields of application, including low-temperature mineral precipitation and biomineralisation, Earth surface processes and global cycling, high-temperature processes and cosmochemistry, and lastly human studies and biomedical applications. The current state of the art in these major areas is discussed, and open questions and possible future directions are identified. In terms of its depth and coverage, the current work extends and complements the previous reviews of Ca stable isotope geochemistry, addressing the needs of graduate students and advanced researchers who want to familiarize themselves with Ca stable isotope research.

Hand Gesture Recognition with Leap Motion

OpenAIRE

Du, Youchen; Liu, Shenglan; Feng, Lin; Chen, Menghui; Wu, Jie

2017-01-01

The recent introduction of depth cameras like Leap Motion Controller allows researchers to exploit the depth information to recognize hand gesture more robustly. This paper proposes a novel hand gesture recognition system with Leap Motion Controller. A series of features are extracted from Leap Motion tracking data, we feed these features along with HOG feature extracted from sensor images into a multi-class SVM classifier to recognize performed gesture, dimension reduction and feature weight...

Simulating intrafraction prostate motion with a random walk model.

Science.gov (United States)

Pommer, Tobias; Oh, Jung Hun; Munck Af Rosenschöld, Per; Deasy, Joseph O

2017-01-01

Prostate motion during radiation therapy (ie, intrafraction motion) can cause unwanted loss of radiation dose to the prostate and increased dose to the surrounding organs at risk. A compact but general statistical description of this motion could be useful for simulation of radiation therapy delivery or margin calculations. We investigated whether prostate motion could be modeled with a random walk model. Prostate motion recorded during 548 radiation therapy fractions in 17 patients was analyzed and used for input in a random walk prostate motion model. The recorded motion was categorized on the basis of whether any transient excursions (ie, rapid prostate motion in the anterior and superior direction followed by a return) occurred in the trace and transient motion. This was separately modeled as a large step in the anterior/superior direction followed by a returning large step. Random walk simulations were conducted with and without added artificial transient motion using either motion data from all observed traces or only traces without transient excursions as model input, respectively. A general estimate of motion was derived with reasonable agreement between simulated and observed traces, especially during the first 5 minutes of the excursion-free simulations. Simulated and observed diffusion coefficients agreed within 0.03, 0.2 and 0.3 mm 2 /min in the left/right, superior/inferior, and anterior/posterior directions, respectively. A rapid increase in variance at the start of observed traces was difficult to reproduce and seemed to represent the patient's need to adjust before treatment. This could be estimated somewhat using artificial transient motion. Random walk modeling is feasible and recreated the characteristics of the observed prostate motion. Introducing artificial transient motion did not improve the overall agreement, although the first 30 seconds of the traces were better reproduced. The model provides a simple estimate of prostate motion during

Motion artifacts in computed tomography

International Nuclear Information System (INIS)

Yang, C.K.

1979-01-01

In the year 1972, the first Computed Tomography Scanner (or CT) was introduced and caused a revolution in the field of Diagnostic Radiology. A tomogram is a cross-sectional image of a three-dimensional object obtained through non-invasive measurements. The image that is presented is very similar to what would be seen if a thin cross-sectional slice of the patient was examined. In Computed Tomography, x-rays are passed through the body of a patient in many different directions and their attenuation is detected. By using some mathematical theorems, the attenuation information can be converted into the density of the patient along the x-ray path. Combined with modern sophisticated computer signal processing technology, a cross-sectional image can be generated and displayed on a TV monitor. Usually a good CT image relies on the patient not moving during the x-ray scanning. However, for some unconscious or severely ill patients, this is very difficult to achieve. Thus, the motion during the scan causes the so-called motion artifacts which distort the displayed image and sometimes these motion artifacts make diagnosis impossible. Today, to remove or avoid motion artifacts is one of the major efforts in developing new scanner systems. In this thesis, a better understanding of the motion artifacts problem in CT scaning is gained through computer simulations, real scanner experiments and theoretical analyses. The methods by which the distorted image can be improved are simulated also. In particular, it is assumed that perfect knowledge of the patient motion is known since this represents the theoretical limit on how well the distorted image can be improved

Fast Numerical Simulation of Focused Ultrasound Treatments During Respiratory Motion With Discontinuous Motion Boundaries.

Science.gov (United States)

Schwenke, Michael; Georgii, Joachim; Preusser, Tobias

2017-07-01

Focused ultrasound (FUS) is rapidly gaining clinical acceptance for several target tissues in the human body. Yet, treating liver targets is not clinically applied due to a high complexity of the procedure (noninvasiveness, target motion, complex anatomy, blood cooling effects, shielding by ribs, and limited image-based monitoring). To reduce the complexity, numerical FUS simulations can be utilized for both treatment planning and execution. These use-cases demand highly accurate and computationally efficient simulations. We propose a numerical method for the simulation of abdominal FUS treatments during respiratory motion of the organs and target. Especially, a novel approach is proposed to simulate the heating during motion by solving Pennes' bioheat equation in a computational reference space, i.e., the equation is mathematically transformed to the reference. The approach allows for motion discontinuities, e.g., the sliding of the liver along the abdominal wall. Implementing the solver completely on the graphics processing unit and combining it with an atlas-based ultrasound simulation approach yields a simulation performance faster than real time (less than 50-s computing time for 100 s of treatment time) on a modern off-the-shelf laptop. The simulation method is incorporated into a treatment planning demonstration application that allows to simulate real patient cases including respiratory motion. The high performance of the presented simulation method opens the door to clinical applications. The methods bear the potential to enable the application of FUS for moving organs.

Predicting articulated human motion from spatial processes

DEFF Research Database (Denmark)

Hauberg, Søren; Pedersen, Kim Steenstrup

2011-01-01

recent work where prior models are derived in terms of joint angles. This approach has several advantages. First of all, it allows us to construct motion models in low dimensional spaces, which makes motion estimation more robust. Secondly, as many types of motion are easily expressed in spatial...

Langevin theory of anomalous Brownian motion made simple

International Nuclear Information System (INIS)

Tothova, Jana; Vasziova, Gabriela; Lisy, VladimIr; Glod, Lukas

2011-01-01

During the century from the publication of the work by Einstein (1905 Ann. Phys. 17 549) Brownian motion has become an important paradigm in many fields of modern science. An essential impulse for the development of Brownian motion theory was given by the work of Langevin (1908 C. R. Acad. Sci., Paris 146 530), in which he proposed an 'infinitely more simple' description of Brownian motion than that by Einstein. The original Langevin approach has however strong limitations, which were rigorously stated after the creation of the hydrodynamic theory of Brownian motion (1945). Hydrodynamic Brownian motion is a special case of 'anomalous Brownian motion', now intensively studied both theoretically and in experiments. We show how some general properties of anomalous Brownian motion can be easily derived using an effective method that allows one to convert the stochastic generalized Langevin equation into a deterministic Volterra-type integro-differential equation for the mean square displacement of the particle. Within the Gibbs statistics, the method is applicable to linear equations of motion with any kind of memory during the evolution of the system. We apply it to memoryless Brownian motion in a harmonic potential well and to Brownian motion in fluids, taking into account the effects of hydrodynamic memory. Exploring the mathematical analogy between Brownian motion and electric circuits, which are at nanoscales also described by the generalized Langevin equation, we calculate the fluctuations of charge and current in RLC circuits that are in contact with the thermal bath. Due to the simplicity of our approach it could be incorporated into graduate courses of statistical physics. Once the method is established, it allows bringing to the attention of students and effectively solving a number of attractive problems related to Brownian motion.

Exoskeleton Motion Control for Children Walking Rehabilitation

Directory of Open Access Journals (Sweden)

Cristina Ploscaru

2016-06-01

Full Text Available This paper introduces a quick method for motion control of an exoskeleton used on children walking rehabilitation with ages between four to seven years old. The exoskeleton used on this purpose has six servomotors which work independently and actuates each human lower limb joints (hips, knees and ankles. For obtaining the desired motion laws, a high-speed motion analysis equipment was used. The experimental rough data were mathematically modeled in order to obtain the proper motion equations for controlling the exoskeleton servomotors.

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.

Soliton motion in a parametrically ac-driven damped Toda lattice

International Nuclear Information System (INIS)

Rasmussen, K.O.; Malomed, B.A.; Bishop, A.R.; Groenbech-Jensen, N.

1998-01-01

We demonstrate that a staggered parametric ac driving term can support stable progressive motion of a soliton in a Toda lattice with friction, while an unstaggered driving force cannot. A physical context of the model is that of a chain of anharmonically coupled particles adsorbed on a solid surface of a finite size. The ac driving force is generated by a standing acoustic wave excited on the surface. Simulations demonstrate that the state left behind the moving soliton, with the particles shifted from their equilibrium positions, gradually relaxes back to the equilibrium state that existed before the passage of the soliton. The perturbation theory predicts that the ac-driven soliton exists if the amplitude of the drive exceeds a certain threshold. The analytical prediction for the threshold is in reasonable agreement with that found numerically. Collisions between two counterpropagating solitons is also simulated, demonstrating that the collisions are, effectively, fully elastic. copyright 1998 The American Physical Society

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...

14 CFR 406.141 - Motions.

Science.gov (United States)

2010-01-01

... cause shown, a party must file any prehearing motion with the Federal Docket Management System and serve... for more definite statement. A respondent may file a motion requesting a more definite statement of... pleading and must submit the details that the party believes would make the allegation or response definite...

45 CFR 672.9 - Motions.

Science.gov (United States)

2010-10-01

... memorandum relied upon. (b) Response to motions. A party must file a response to any written motion within..., shall (1) be in writing; (2) state the basis or grounds with particularity; (3) set forth the relief or... response shall be accompanied by any affidavit, certificate, other evidence, or legal memorandum relied...

Prospective motion correction with volumetric navigators (vNavs) reduces the bias and variance in brain morphometry induced by subject motion.

Science.gov (United States)

Tisdall, M Dylan; Reuter, Martin; Qureshi, Abid; Buckner, Randy L; Fischl, Bruce; van der Kouwe, André J W

2016-02-15

Recent work has demonstrated that subject motion produces systematic biases in the metrics computed by widely used morphometry software packages, even when the motion is too small to produce noticeable image artifacts. In the common situation where the control population exhibits different behaviors in the scanner when compared to the experimental population, these systematic measurement biases may produce significant confounds for between-group analyses, leading to erroneous conclusions about group differences. While previous work has shown that prospective motion correction can improve perceived image quality, here we demonstrate that, in healthy subjects performing a variety of directed motions, the use of the volumetric navigator (vNav) prospective motion correction system significantly reduces the motion-induced bias and variance in morphometry. Copyright © 2015 Elsevier Inc. All rights reserved.

Forecasting pulsatory motion for non-invasive cardiac radiosurgery: an analysis of algorithms from respiratory motion prediction.

Science.gov (United States)

Ernst, Floris; Bruder, Ralf; Schlaefer, Alexander; Schweikard, Achim

2011-01-01

Recently, radiosurgical treatment of cardiac arrhythmia, especially atrial fibrillation, has been proposed. Using the CyberKnife, focussed radiation will be used to create ablation lines on the beating heart to block unwanted electrical activity. Since this procedure requires high accuracy, the inevitable latency of the system (i.e., the robotic manipulator following the motion of the heart) has to be compensated for. We examine the applicability of prediction algorithms developed for respiratory motion prediction to the prediction of pulsatory motion. We evaluated the MULIN, nLMS, wLMS, SVRpred and EKF algorithms. The test data used has been recorded using external infrared position sensors, 3D ultrasound and the NavX catheter systems. With this data, we have shown that the error from latency can be reduced by at least 10 and as much as 75% (44% average), depending on the type of signal. It has also been shown that, although the SVRpred algorithm was successful in most cases, it was outperformed by the simple nLMS algorithm, the EKF or the wLMS algorithm in a number of cases. We have shown that prediction of cardiac motion is possible and that the algorithms known from respiratory motion prediction are applicable. Since pulsation is more regular than respiration, more research will have to be done to improve frequency-tracking algorithms, like the EKF method, which performed better than expected from their behaviour on respiratory motion traces.

User-Independent Motion State Recognition Using Smartphone Sensors.

Science.gov (United States)

Gu, Fuqiang; Kealy, Allison; Khoshelham, Kourosh; Shang, Jianga

2015-12-04

The recognition of locomotion activities (e.g., walking, running, still) is important for a wide range of applications like indoor positioning, navigation, location-based services, and health monitoring. Recently, there has been a growing interest in activity recognition using accelerometer data. However, when utilizing only acceleration-based features, it is difficult to differentiate varying vertical motion states from horizontal motion states especially when conducting user-independent classification. In this paper, we also make use of the newly emerging barometer built in modern smartphones, and propose a novel feature called pressure derivative from the barometer readings for user motion state recognition, which is proven to be effective for distinguishing vertical motion states and does not depend on specific users' data. Seven types of motion states are defined and six commonly-used classifiers are compared. In addition, we utilize the motion state history and the characteristics of people's motion to improve the classification accuracies of those classifiers. Experimental results show that by using the historical information and human's motion characteristics, we can achieve user-independent motion state classification with an accuracy of up to 90.7%. In addition, we analyze the influence of the window size and smartphone pose on the accuracy.

User-Independent Motion State Recognition Using Smartphone Sensors

Directory of Open Access Journals (Sweden)

Fuqiang Gu

2015-12-01

Full Text Available The recognition of locomotion activities (e.g., walking, running, still is important for a wide range of applications like indoor positioning, navigation, location-based services, and health monitoring. Recently, there has been a growing interest in activity recognition using accelerometer data. However, when utilizing only acceleration-based features, it is difficult to differentiate varying vertical motion states from horizontal motion states especially when conducting user-independent classification. In this paper, we also make use of the newly emerging barometer built in modern smartphones, and propose a novel feature called pressure derivative from the barometer readings for user motion state recognition, which is proven to be effective for distinguishing vertical motion states and does not depend on specific users’ data. Seven types of motion states are defined and six commonly-used classifiers are compared. In addition, we utilize the motion state history and the characteristics of people’s motion to improve the classification accuracies of those classifiers. Experimental results show that by using the historical information and human’s motion characteristics, we can achieve user-independent motion state classification with an accuracy of up to 90.7%. In addition, we analyze the influence of the window size and smartphone pose on the accuracy.

Dynamic signatures of driven vortex motion.

Energy Technology Data Exchange (ETDEWEB)

Crabtree, G. W.; Kwok, W. K.; Lopez, D.; Olsson, R. J.; Paulius, L. M.; Petrean, A. M.; Safar, H.

1999-09-16

We probe the dynamic nature of driven vortex motion in superconductors with a new type of transport experiment. An inhomogeneous Lorentz driving force is applied to the sample, inducing vortex velocity gradients that distinguish the hydrodynamic motion of the vortex liquid from the elastic and-plastic motion of the vortex solid. We observe elastic depinning of the vortex lattice at the critical current, and shear induced plastic slip of the lattice at high Lorentz force gradients.

Teaching Motion with the Global Positioning System

Science.gov (United States)

Budisa, Marko; Planinsic, Gorazd

2003-01-01

We have used the GPS receiver and a PC interface to track different types of motion. Various hands-on experiments that enlighten the physics of motion at the secondary school level are suggested (visualization of 2D and 3D motion, measuring car drag coefficient and fuel consumption). (Contains 8 figures.)

Velocities and joint angles during double backward stretched salto performed with stable landing and in combination with tempo salto

Directory of Open Access Journals (Sweden)

J Sadowski

2009-07-01

Full Text Available The aim of the study was to compare the values of velocity an joint angles obtained during performance of double salto backward stretched with a stable landing and its combination with salto tempo. Seven top level acrobats (track jumpers participated in study. Mean values of body height, mass and age had a value of: 170 cm ± 4.0 cm, 72.4 kg ± 3.6 kg, 20.4±1.7 years, respectively. The studies were conducted on a standard acrobatic path (type PTS 2000. Two digital video cameras (240 Hz and APAS 2000 (Ariel Dynamics Inc. were used during studies. Markers were placed in ankle, knee, hip, arm, elbow and wrist joints. All marker positions were tracked and reconstructed using the APAS system. Two sequences with the following elements were analysed: round-off - double salto backward stretched (A and round-off - double salto backward stretched - tempo salto (B. The highest differences between the key components describing performance of presented exercises exist for joint angles during launching and landing position, and resultant velocities during touchdown. In version A the athlete created prerequisites for “gliding” double salto backward stretched by means of the body segments motions, whereas in version B he executes faster motions of the body segments accentuating his actions upon backward rotation of the body. During the final phase of double salto backward stretched in combination with tempo salto the athlete performed courbette “under himself” (almost straight feet are placed in front of vertical line, pushes directly back and in 0,1 s executes stable arm swing upward-backward to tempo salto.

Compensating for Quasi-periodic Motion in Robotic Radiosurgery

CERN Document Server

Ernst, Floris

2012-01-01

Compensating for Quasi-periodic Motion in Robotic Radiosurgery outlines the techniques needed to accurately track and compensate for respiratory and pulsatory motion during robotic radiosurgery. The algorithms presented within the book aid in the treatment of tumors that move during respiration. In Chapters 1 and 2,  the book introduces the concept of stereotactic body radiation therapy, motion compensation strategies and the clinical state-of-the-art. In Chapters 3 through 5, the author describes and evaluates new methods for motion prediction, for correlating external motion to internal organ motion, and for the evaluation of these algorithms’ output based on an unprecedented amount of real clinical data. Finally, Chapter 6 provides a brief introduction into currently investigated, open questions and further fields of research. Compensating for Quasi-periodic Motion in Robotic Radiosurgery targets researchers working in the related fields of surgical oncology, artificial intelligence, robotics and more. ...

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.

Unpredictably Stable

DEFF Research Database (Denmark)

Failla, Virgilio; Melillo, Francesca; Reichstein, Toke

2014-01-01

Is entrepreneurship a more stable career choice for high employment turnover individuals? We find that a transition to entrepreneurship induces a shift towards stayer behavior and identify job matching, job satisfaction and lock-in effects as main drivers. These findings have major implications...

Stroboscopic Goggles for Reduction of Motion Sickness

Science.gov (United States)

Reschke, M. F.; Somers, Jeffrey T.

2005-01-01

A device built around a pair of electronic shutters has been demonstrated to be effective as a prototype of stroboscopic goggles or eyeglasses for preventing or reducing motion sickness. The momentary opening of the shutters helps to suppress a phenomenon that is known in the art as retinal slip and is described more fully below. While a number of different environmental factors can induce motion sickness, a common factor associated with every known motion environment is sensory confusion or sensory mismatch. Motion sickness is a product of misinformation arriving at a central point in the nervous system from the senses from which one determines one s spatial orientation. When information from the eyes, ears, joints, and pressure receptors are all in agreement as to one s orientation, there is no motion sickness. When one or more sensory input(s) to the brain is not expected, or conflicts with what is anticipated, the end product is motion sickness. Normally, an observer s eye moves, compensating for the anticipated effect of motion, in such a manner that the image of an object moving relatively to an observer is held stationary on the retina. In almost every known environment that induces motion sickness, a change in the gain (in the signal-processing sense of gain ) of the vestibular system causes the motion of the eye to fail to hold images stationary on the retina, and the resulting motion of the images is termed retinal slip. The present concept of stroboscopic goggles or eyeglasses (see figure) is based on the proposition that prevention of retinal slip, and hence, the prevention of sensory mismatch, can be expected to reduce the tendency toward motion sickness. A device according to this concept helps to prevent retinal slip by providing snapshots of the visual environment through electronic shutters that are brief enough that each snapshot freezes the image on each retina. The exposure time for each snapshot is less than 5 ms. In the event that a higher

Amputation effects on the underlying complexity within transtibial amputee ankle motion

Energy Technology Data Exchange (ETDEWEB)

Wurdeman, Shane R., E-mail: shanewurdeman@gmail.com [Nebraska Biomechanics Core Facility, University of Nebraska at Omaha, Omaha, Nebraska 68182 (United States); Advanced Prosthetics Center, Omaha, Nebraska 68134 (United States); Myers, Sara A. [Nebraska Biomechanics Core Facility, University of Nebraska at Omaha, Omaha, Nebraska 68182 (United States); Stergiou, Nicholas [Nebraska Biomechanics Core Facility, University of Nebraska at Omaha, Omaha, Nebraska 68182 (United States); College of Public Health, University of Nebraska Medical Center, Omaha, Nebraska 68198 (United States)

2014-03-15

The presence of chaos in walking is considered to provide a stable, yet adaptable means for locomotion. This study examined whether lower limb amputation and subsequent prosthetic rehabilitation resulted in a loss of complexity in amputee gait. Twenty-eight individuals with transtibial amputation participated in a 6 week, randomized cross-over design study in which they underwent a 3 week adaptation period to two separate prostheses. One prosthesis was deemed “more appropriate” and the other “less appropriate” based on matching/mismatching activity levels of the person and the prosthesis. Subjects performed a treadmill walking trial at self-selected walking speed at multiple points of the adaptation period, while kinematics of the ankle were recorded. Bilateral sagittal plane ankle motion was analyzed for underlying complexity through the pseudoperiodic surrogation analysis technique. Results revealed the presence of underlying deterministic structure in both prostheses and both the prosthetic and sound leg ankle (discriminant measure largest Lyapunov exponent). Results also revealed that the prosthetic ankle may be more likely to suffer loss of complexity than the sound ankle, and a “more appropriate” prosthesis may be better suited to help restore a healthy complexity of movement within the prosthetic ankle motion compared to a “less appropriate” prosthesis (discriminant measure sample entropy). Results from sample entropy results are less likely to be affected by the intracycle periodic dynamics as compared to the largest Lyapunov exponent. Adaptation does not seem to influence complexity in the system for experienced prosthesis users.

Amputation effects on the underlying complexity within transtibial amputee ankle motion

International Nuclear Information System (INIS)

Wurdeman, Shane R.; Myers, Sara A.; Stergiou, Nicholas

2014-01-01

The presence of chaos in walking is considered to provide a stable, yet adaptable means for locomotion. This study examined whether lower limb amputation and subsequent prosthetic rehabilitation resulted in a loss of complexity in amputee gait. Twenty-eight individuals with transtibial amputation participated in a 6 week, randomized cross-over design study in which they underwent a 3 week adaptation period to two separate prostheses. One prosthesis was deemed “more appropriate” and the other “less appropriate” based on matching/mismatching activity levels of the person and the prosthesis. Subjects performed a treadmill walking trial at self-selected walking speed at multiple points of the adaptation period, while kinematics of the ankle were recorded. Bilateral sagittal plane ankle motion was analyzed for underlying complexity through the pseudoperiodic surrogation analysis technique. Results revealed the presence of underlying deterministic structure in both prostheses and both the prosthetic and sound leg ankle (discriminant measure largest Lyapunov exponent). Results also revealed that the prosthetic ankle may be more likely to suffer loss of complexity than the sound ankle, and a “more appropriate” prosthesis may be better suited to help restore a healthy complexity of movement within the prosthetic ankle motion compared to a “less appropriate” prosthesis (discriminant measure sample entropy). Results from sample entropy results are less likely to be affected by the intracycle periodic dynamics as compared to the largest Lyapunov exponent. Adaptation does not seem to influence complexity in the system for experienced prosthesis users

Commercially available video motion detectors

International Nuclear Information System (INIS)

1979-01-01

A market survey of commercially available video motion detection systems was conducted by the Intrusion Detection Systems Technology Division of Sandia Laboratories. The information obtained from this survey is summarized in this report. The cutoff date for this information is May 1978. A list of commercially available video motion detection systems is appended

Randomized Clinical Trial with e-MotionalTraining® 1.0 for Social Cognition Rehabilitation in Schizophrenia

Directory of Open Access Journals (Sweden)

Yolanda Maroño Souto

2018-02-01

Full Text Available BackgroundSchizophrenia patients present deficits in social cognition (SC, emotion and social perception, theory of mind (ToM, and attributional style. This study tested the efficacy, in real clinical conditions, of a online self-training program in SC, e-Motional Training®, in comparison with treatment as usual.MethodA randomized single-blinded multicenter clinical trial was conducted with 60 schizophrenia stable outpatients. All patients (control and intervention were treated with drug therapy, case management, and individual and group psychotherapy (not focused on SC. Intervention group was treated with e-Motional Training®, an online program devised for SC rehabilitation.Statistical analysisA descriptive analysis and parametric/non-parametric tests were used to compare both groups at baseline. Analysis of covariance was used to compared post–pre changes in SC between the two interventions. If the group effect was significant, follow-up univariate test (t-test for dependent samples was carried out in each group to verify whether the effect was due to improvement in the intervention group or deterioration in the control group. We considered statistically significant differences with P < 0.05.ResultsSignificant improvements were obtained in the intervention group in emotion recognition and most ToM variables in comparison with the control group.Discussione-Motional Training® seems to be a promising online training tool for SC deficits in schizophrenia, covering the lack of similar intervention instruments in our community.

Large-scale motions in the universe: a review

International Nuclear Information System (INIS)

Burstein, D.

1990-01-01

The expansion of the universe can be retarded in localised regions within the universe both by the presence of gravity and by non-gravitational motions generated in the post-recombination universe. The motions of galaxies thus generated are called 'peculiar motions', and the amplitudes, size scales and coherence of these peculiar motions are among the most direct records of the structure of the universe. As such, measurements of these properties of the present-day universe provide some of the severest tests of cosmological theories. This is a review of the current evidence for large-scale motions of galaxies out to a distance of ∼5000 km s -1 (in an expanding universe, distance is proportional to radial velocity). 'Large-scale' in this context refers to motions that are correlated over size scales larger than the typical sizes of groups of galaxies, up to and including the size of the volume surveyed. To orient the reader into this relatively new field of study, a short modern history is given together with an explanation of the terminology. Careful consideration is given to the data used to measure the distances, and hence the peculiar motions, of galaxies. The evidence for large-scale motions is presented in a graphical fashion, using only the most reliable data for galaxies spanning a wide range in optical properties and over the complete range of galactic environments. The kinds of systematic errors that can affect this analysis are discussed, and the reliability of these motions is assessed. The predictions of two models of large-scale motion are compared to the observations, and special emphasis is placed on those motions in which our own Galaxy directly partakes. (author)

Real Time MRI Motion Correction with Markerless Tracking

DEFF Research Database (Denmark)

Benjaminsen, Claus; Jensen, Rasmus Ramsbøl; Wighton, Paul

Prospective motion correction for MRI neuroimaging has been demonstrated using MR navigators and external tracking systems using markers. The drawbacks of these two motion estimation methods include prolonged scan time plus lack of compatibility with all image acquisitions, and difficulties...... validating marker attachment resulting in uncertain estimation of the brain motion respectively. We have developed a markerless tracking system, and in this work we demonstrate the use of our system for prospective motion correction, and show that despite being computationally demanding, markerless tracking...... can be implemented for real time motion correction....

Individuality and togetherness in joint improvised motion.

Directory of Open Access Journals (Sweden)

Yuval Hart

Full Text Available Actors, dancers and musicians that improvise together report special moments of togetherness: high performance and synchrony, seemingly without a leader and a follower. Togetherness seems to conflict with individuality- the idiosyncratic character of each person's performance. To understand the relation of individuality and togetherness, we employed the mirror game paradigm in which two players are asked to mirror each other and create interesting synchronized motion, with and without a designated leader. The mirror game enables quantitative characterization of moments of togetherness in which complex motion is generated with high synchrony. We find that each person as a leader does basic strokes of motion with a characteristic signature, in terms of the shape of their velocity profile between two stopping events. In moments of togetherness both players change their signature to a universal stroke shape. This universal velocity profile resembles a half-period of a sine wave, and is therefore symmetric and maximally smooth. Thus, instead of converging to an intermediate motion signature, or having one player dominate, players seem to shift their basic motion signatures to a shape that is altogether different from their individually preferred shapes; the resulting motion may be easier to predict and to agree on. The players then build complex motion by using such smooth elementary strokes.

Individuality and togetherness in joint improvised motion.

Science.gov (United States)

Hart, Yuval; Noy, Lior; Feniger-Schaal, Rinat; Mayo, Avraham E; Alon, Uri

2014-01-01

Actors, dancers and musicians that improvise together report special moments of togetherness: high performance and synchrony, seemingly without a leader and a follower. Togetherness seems to conflict with individuality- the idiosyncratic character of each person's performance. To understand the relation of individuality and togetherness, we employed the mirror game paradigm in which two players are asked to mirror each other and create interesting synchronized motion, with and without a designated leader. The mirror game enables quantitative characterization of moments of togetherness in which complex motion is generated with high synchrony. We find that each person as a leader does basic strokes of motion with a characteristic signature, in terms of the shape of their velocity profile between two stopping events. In moments of togetherness both players change their signature to a universal stroke shape. This universal velocity profile resembles a half-period of a sine wave, and is therefore symmetric and maximally smooth. Thus, instead of converging to an intermediate motion signature, or having one player dominate, players seem to shift their basic motion signatures to a shape that is altogether different from their individually preferred shapes; the resulting motion may be easier to predict and to agree on. The players then build complex motion by using such smooth elementary strokes.

Human Perception of Ambiguous Inertial Motion Cues

Science.gov (United States)

Zhang, Guan-Lu

2010-01-01

Human daily activities on Earth involve motions that elicit both tilt and translation components of the head (i.e. gazing and locomotion). With otolith cues alone, tilt and translation can be ambiguous since both motions can potentially displace the otolithic membrane by the same magnitude and direction. Transitions between gravity environments (i.e. Earth, microgravity and lunar) have demonstrated to alter the functions of the vestibular system and exacerbate the ambiguity between tilt and translational motion cues. Symptoms of motion sickness and spatial disorientation can impair human performances during critical mission phases. Specifically, Space Shuttle landing records show that particular cases of tilt-translation illusions have impaired the performance of seasoned commanders. This sensorimotor condition is one of many operational risks that may have dire implications on future human space exploration missions. The neural strategy with which the human central nervous system distinguishes ambiguous inertial motion cues remains the subject of intense research. A prevailing theory in the neuroscience field proposes that the human brain is able to formulate a neural internal model of ambiguous motion cues such that tilt and translation components can be perceptually decomposed in order to elicit the appropriate bodily response. The present work uses this theory, known as the GIF resolution hypothesis, as the framework for experimental hypothesis. Specifically, two novel motion paradigms are employed to validate the neural capacity of ambiguous inertial motion decomposition in ground-based human subjects. The experimental setup involves the Tilt-Translation Sled at Neuroscience Laboratory of NASA JSC. This two degree-of-freedom motion system is able to tilt subjects in the pitch plane and translate the subject along the fore-aft axis. Perception data will be gathered through subject verbal reports. Preliminary analysis of perceptual data does not indicate that

Motion-compensated cone beam computed tomography using a conjugate gradient least-squares algorithm and electrical impedance tomography imaging motion data.

Science.gov (United States)

Pengpen, T; Soleimani, M

2015-06-13

Cone beam computed tomography (CBCT) is an imaging modality that has been used in image-guided radiation therapy (IGRT). For applications such as lung radiation therapy, CBCT images are greatly affected by the motion artefacts. This is mainly due to low temporal resolution of CBCT. Recently, a dual modality of electrical impedance tomography (EIT) and CBCT has been proposed, in which the high temporal resolution EIT imaging system provides motion data to a motion-compensated algebraic reconstruction technique (ART)-based CBCT reconstruction software. High computational time associated with ART and indeed other variations of ART make it less practical for real applications. This paper develops a motion-compensated conjugate gradient least-squares (CGLS) algorithm for CBCT. A motion-compensated CGLS offers several advantages over ART-based methods, including possibilities for explicit regularization, rapid convergence and parallel computations. This paper for the first time demonstrates motion-compensated CBCT reconstruction using CGLS and reconstruction results are shown in limited data CBCT considering only a quarter of the full dataset. The proposed algorithm is tested using simulated motion data in generic motion-compensated CBCT as well as measured EIT data in dual EIT-CBCT imaging. © 2015 The Author(s) Published by the Royal Society. All rights reserved.