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Sample records for multiple motion model

  1. Safe motion planning for mobile agents: A model of reactive planning for multiple mobile agents

    SciTech Connect

    Fujimura, Kikuo.

    1990-01-01

    The problem of motion planning for multiple mobile agents is studied. Each planning agent independently plans its own action based on its map which contains a limited information about the environment. In an environment where more than one mobile agent interacts, the motions of the robots are uncertain and dynamic. A model for reactive agents is described and simulation results are presented to show their behavior patterns. 18 refs., 2 figs.

  2. Conditional spectrum computation incorporating multiple causal earthquakes and ground-motion prediction models

    USGS Publications Warehouse

    Lin, Ting; Harmsen, Stephen C.; Baker, Jack W.; Luco, Nicolas

    2013-01-01

    The conditional spectrum (CS) is a target spectrum (with conditional mean and conditional standard deviation) that links seismic hazard information with ground-motion selection for nonlinear dynamic analysis. Probabilistic seismic hazard analysis (PSHA) estimates the ground-motion hazard by incorporating the aleatory uncertainties in all earthquake scenarios and resulting ground motions, as well as the epistemic uncertainties in ground-motion prediction models (GMPMs) and seismic source models. Typical CS calculations to date are produced for a single earthquake scenario using a single GMPM, but more precise use requires consideration of at least multiple causal earthquakes and multiple GMPMs that are often considered in a PSHA computation. This paper presents the mathematics underlying these more precise CS calculations. Despite requiring more effort to compute than approximate calculations using a single causal earthquake and GMPM, the proposed approach produces an exact output that has a theoretical basis. To demonstrate the results of this approach and compare the exact and approximate calculations, several example calculations are performed for real sites in the western United States. The results also provide some insights regarding the circumstances under which approximate results are likely to closely match more exact results. To facilitate these more precise calculations for real applications, the exact CS calculations can now be performed for real sites in the United States using new deaggregation features in the U.S. Geological Survey hazard mapping tools. Details regarding this implementation are discussed in this paper.

  3. Modeling Confidence Judgments, Response Times, and Multiple Choices in Decision Making: Recognition Memory and Motion Discrimination

    PubMed Central

    Ratcliff, Roger; Starns, Jeffrey J.

    2014-01-01

    Confidence in judgments is a fundamental aspect of decision making, and tasks that collect confidence judgments are an instantiation of multiple-choice decision making. We present a model for confidence judgments in recognition memory tasks that uses a multiple-choice diffusion decision process with separate accumulators of evidence for the different confidence choices. The accumulator that first reaches its decision boundary determines which choice is made. Five algorithms for accumulating evidence were compared, and one of them produced proportions of responses for each of the choices and full response time distributions for each choice that closely matched empirical data. With this algorithm, an increase in the evidence in one accumulator is accompanied by a decrease in the others so that the total amount of evidence in the system is constant. Application of the model to the data from an earlier experiment (Ratcliff, McKoon, & Tindall, 1994) uncovered a relationship between the shapes of z-transformed receiver operating characteristics and the behavior of response time distributions. Both are explained in the model by the behavior of the decision boundaries. For generality, we also applied the decision model to a 3-choice motion discrimination task and found it accounted for data better than a competing class of models. The confidence model presents a coherent account of confidence judgments and response time that cannot be explained with currently popular signal detection theory analyses or dual-process models of recognition. PMID:23915088

  4. Probability distribution of financial returns in a model of multiplicative Brownian motion with stochastic diffusion coefficient

    NASA Astrophysics Data System (ADS)

    Silva, Antonio

    2005-03-01

    It is well-known that the mathematical theory of Brownian motion was first developed in the Ph. D. thesis of Louis Bachelier for the French stock market before Einstein [1]. In Ref. [2] we studied the so-called Heston model, where the stock-price dynamics is governed by multiplicative Brownian motion with stochastic diffusion coefficient. We solved the corresponding Fokker-Planck equation exactly and found an analytic formula for the time-dependent probability distribution of stock price changes (returns). The formula interpolates between the exponential (tent-shaped) distribution for short time lags and the Gaussian (parabolic) distribution for long time lags. The theoretical formula agrees very well with the actual stock-market data ranging from the Dow-Jones index [2] to individual companies [3], such as Microsoft, Intel, etc. [] [1] Louis Bachelier, ``Th'eorie de la sp'eculation,'' Annales Scientifiques de l''Ecole Normale Sup'erieure, III-17:21-86 (1900).[] [2] A. A. Dragulescu and V. M. Yakovenko, ``Probability distribution of returns in the Heston model with stochastic volatility,'' Quantitative Finance 2, 443--453 (2002); Erratum 3, C15 (2003). [cond-mat/0203046] [] [3] A. C. Silva, R. E. Prange, and V. M. Yakovenko, ``Exponential distribution of financial returns at mesoscopic time lags: a new stylized fact,'' Physica A 344, 227--235 (2004). [cond-mat/0401225

  5. A multiple model approach to respiratory motion prediction for real-time IGRT.

    PubMed

    Putra, Devi; Haas, Olivier C L; Mills, John A; Burnham, Keith J

    2008-03-21

    Respiration induces significant movement of tumours in the vicinity of thoracic and abdominal structures. Real-time image-guided radiotherapy (IGRT) aims to adapt radiation delivery to tumour motion during irradiation. One of the main problems for achieving this objective is the presence of time lag between the acquisition of tumour position and the radiation delivery. Such time lag causes significant beam positioning errors and affects the dose coverage. A method to solve this problem is to employ an algorithm that is able to predict future tumour positions from available tumour position measurements. This paper presents a multiple model approach to respiratory-induced tumour motion prediction using the interacting multiple model (IMM) filter. A combination of two models, constant velocity (CV) and constant acceleration (CA), is used to capture respiratory-induced tumour motion. A Kalman filter is designed for each of the local models and the IMM filter is applied to combine the predictions of these Kalman filters for obtaining the predicted tumour position. The IMM filter, likewise the Kalman filter, is a recursive algorithm that is suitable for real-time applications. In addition, this paper proposes a confidence interval (CI) criterion to evaluate the performance of tumour motion prediction algorithms for IGRT. The proposed CI criterion provides a relevant measure for the prediction performance in terms of clinical applications and can be used to specify the margin to accommodate prediction errors. The prediction performance of the IMM filter has been evaluated using 110 traces of 4-minute free-breathing motion collected from 24 lung-cancer patients. The simulation study was carried out for prediction time 0.1-0.6 s with sampling rates 3, 5 and 10 Hz. It was found that the prediction of the IMM filter was consistently better than the prediction of the Kalman filter with the CV or CA model. There was no significant difference of prediction errors for the

  6. A continuous 4D motion model from multiple respiratory cycles for use in lung radiotherapy

    SciTech Connect

    McClelland, Jamie R.; Blackall, Jane M.; Tarte, Segolene; Chandler, Adam C.; Hughes, Simon; Ahmad, Shahreen; Landau, David B.; Hawkes, David J.

    2006-09-15

    Respiratory motion causes errors when planning and delivering radiotherapy treatment to lung cancer patients. To reduce these errors, methods of acquiring and using four-dimensional computed tomography (4DCT) datasets have been developed. We have developed a novel method of constructing computational motion models from 4DCT. The motion models attempt to describe an average respiratory cycle, which reduces the effects of variation between different cycles. They require substantially less memory than a 4DCT dataset, are continuous in space and time, and facilitate automatic target propagation and combining of doses over the respiratory cycle. The motion models are constructed from CT data acquired in cine mode while the patient is free breathing (free breathing CT - FBCT). A ''slab'' of data is acquired at each couch position, with 3-4 contiguous slabs being acquired per patient. For each slab a sequence of 20 or 30 volumes was acquired over 20 seconds. A respiratory signal is simultaneously recorded in order to calculate the position in the respiratory cycle for each FBCT. Additionally, a high quality reference CT volume is acquired at breath hold. The reference volume is nonrigidly registered to each of the FBCT volumes. A motion model is then constructed for each slab by temporally fitting the nonrigid registration results. The value of each of the registration parameters is related to the position in the respiratory cycle by fitting an approximating B spline to the registration results. As an approximating function is used, and the data is acquired over several respiratory cycles, the function should model an average respiratory cycle. This can then be used to calculate the value of each degree of freedom at any desired position in the respiratory cycle. The resulting nonrigid transformation will deform the reference volume to predict the contents of the slab at the desired position in the respiratory cycle. The slab model predictions are then concatenated to

  7. A continuous 4D motion model from multiple respiratory cycles for use in lung radiotherapy.

    PubMed

    McClelland, Jamie R; Blackall, Jane M; Tarte, Ségolène; Chandler, Adam C; Hughes, Simon; Ahmad, Shahreen; Landau, David B; Hawkes, David J

    2006-09-01

    Respiratory motion causes errors when planning and delivering radiotherapy treatment to lung cancer patients. To reduce these errors, methods of acquiring and using four-dimensional computed tomography (4DCT) datasets have been developed. We have developed a novel method of constructing computational motion models from 4DCT. The motion models attempt to describe an average respiratory cycle, which reduces the effects of variation between different cycles. They require substantially less memory than a 4DCT dataset, are continuous in space and time, and facilitate automatic target propagation and combining of doses over the respiratory cycle. The motion models are constructed from CT data acquired in cine mode while the patient is free breathing (free breathing CT - FBCT). A "slab" of data is acquired at each couch position, with 3-4 contiguous slabs being acquired per patient. For each slab a sequence of 20 or 30 volumes was acquired over 20 seconds. A respiratory signal is simultaneously recorded in order to calculate the position in the respiratory cycle for each FBCT. Additionally, a high quality reference CT volume is acquired at breath hold. The reference volume is nonrigidly registered to each of the FBCT volumes. A motion model is then constructed for each slab by temporally fitting the nonrigid registration results. The value of each of the registration parameters is related to the position in the respiratory cycle by fitting an approximating B spline to the registration results. As an approximating function is used, and the data is acquired over several respiratory cycles, the function should model an average respiratory cycle. This can then be used to calculate the value of each degree of freedom at any desired position in the respiratory cycle. The resulting nonrigid transformation will deform the reference volume to predict the contents of the slab at the desired position in the respiratory cycle. The slab model predictions are then concatenated to

  8. Typical motions in multiple systems

    NASA Technical Reports Server (NTRS)

    Anosova, Joanna P.

    1990-01-01

    In very old times, people counted - one, two, many. The author wants to show that they were right. Consider the motions of isolated bodies: (1) N = 1 - simple motion; (2) N = 2 - Keplerian orbits; and (3) N = 3 - this is the difficult problem. In general, this problem can be studied only by computer simulations. The author studied this problem over many years (see, e.g., Agekian and Anosova, 1967; Anosova, 1986, 1989 a,b). The principal result is that two basic types of dynamics take place in triple systems. The first special type is the stable hierarchical systems with two almost Keplerian orbits. The second general type is the unstable triple systems with complicated motions of the bodies. By random choice of the initial conditions, by the Monte-Carlo method, the stable systems comprised about approx. 10% of the examined cases; the unstable systems comprised the other approx. 90% of cases under consideration. In N greater than 3, the studies of dynamics of such systems by computer simulations show that we have in general also the motions roughly as at the cases 1 - 3 with the relative negative or positive energies of the bodies. In the author's picture, the typical trajectories of the bodies in unstable triple systems of the general type of dynamics are seen. Such systems are disrupted always after close triple approaches of the bodies. These approaches play a role like the gravitational slingshot. Often, the velocities of escapers are very large. On the other hand, the movie also shows the dynamical processes of a formation, dynamical evolution and disruption of the temporary wide binaries in triples and a formation of final hard massive binaries in the final evolution of triples.

  9. Motion of multiple helical vortices

    NASA Astrophysics Data System (ADS)

    Velasco Fuentes, Oscar

    2015-11-01

    In 1912 Joukowsky deduced that in an unbounded ideal fluid a set of helical vortices--when these are equal, coaxial and symmetrically arranged--would translate and rotate steadily while the vortices preserve their form and relative position. Each vortex is an infinite tube whose cross-section is circular (with radius a) and whose centerline is a helix of pitch L and radius R. The motion is thus determined by three non-dimensional parameters only: the number of vortices N, the vortex radius α = a / R and the vortex pitch τ = L / 2 πR . Here, we express the linear and angular velocities of the vortices as the sum of the mutually induced velocities found by Okulov (2004) and the self-induced velocities found by Velasco Fuentes (2015). We verified that our results are accurate over the whole range of values of the vortices' pitch and radius by numerically computing the vortex motion with two smoothed versions of the Biot-Savart law. It was found that the translation velocity U grows with the number of vortices (N) but decreases as the vortices' radius and pitch (a and τ, respectively) increase; in contrast, the rotation velocity Ω grows with N and a but has a local minimum around τ = 1 for fixed values of N and a.

  10. Motion and force control for multiple cooperative manipulators

    NASA Technical Reports Server (NTRS)

    Wen, John T.; Kreutz, Kenneth

    1989-01-01

    The motion and force control of multiple robot arms manipulating a commonly held object is addressed. A general control paradigm that decouples the motion and force control problems is introduced. For motion control, there are three natural choices: (1) joint torques, (2) arm-tip force vectors, and (3) the acceleration of a generalized coordinate. Choice (1) allows a class of relatively model-independent control laws by exploiting the Hamiltonian structure of the open-loop system; (2) and (3) require the full model information but produce simpler problems. To resolve the nonuniqueness of the joint torques, two methods are introduced. If the arm and object models are available, the allocation of the desired end-effector control force to the joint actuators can be optimized; otherwise the internal force can be controlled about some set point. It is shown that effective force regulation can be achieved even if little model information is available.

  11. Motion and force control for multiple cooperative manipulators

    NASA Technical Reports Server (NTRS)

    Wen, John T.; Kreutz, Kenneth

    1989-01-01

    The motion and force control of multiple robot arms manipulating a commonly held object is addressed. A general control paradigm that decouples the motion and force control problems is introduced. For motion control, there are three natural choices: (1) joint torques, (2) arm-tip force vectors, and (3) the acceleration of a generalized coordinate. Choice (1) allows a class of relatively model-independent control laws by exploiting the Hamiltonian structure of the open-loop system; (2) and (3) require the full model information but produce simpler problems. To resolve the nonuniqueness of the joint torques, two methods are introduced. If the arm and object models are available, the allocation of the desired end-effector control force to the joint actuators can be optimized; otherwise the internal force can be controlled about some set point. It is shown that effective force regulation can be achieved even if little model information is available.

  12. Human motion analysis and modeling

    NASA Astrophysics Data System (ADS)

    Prussing, Keith; Cathcart, J. Michael; Kocher, Brian

    2011-06-01

    Georgia Tech has investigated methods for the detection and tracking of personnel in a variety of acquisition environments. This research effort focused on a detailed phenomenological analysis of human physiology and signatures with the subsequent identification and characterization of potential observables. As a fundamental part of this research effort, Georgia Tech collected motion capture data on an individual for a variety of walking speeds, carrying loads, and load distributions. These data formed the basis for deriving fundamental properties of the individual's motion and supported the development of a physiologically-based human motion model. Subsequently this model aided the derivation and analysis of motion-based observables, particularly changes in the motion of various body components resulting from load variations. This paper will describe the data acquisition process, development of the human motion model, and use of the model in the observable analysis. Video sequences illustrating the motion data and modeling results will also be presented.

  13. Controlling the motion of multiple objects on a Chladni plate

    PubMed Central

    Zhou, Quan; Sariola, Veikko; Latifi, Kourosh; Liimatainen, Ville

    2016-01-01

    The origin of the idea of moving objects by acoustic vibration can be traced back to 1787, when Ernst Chladni reported the first detailed studies on the aggregation of sand onto nodal lines of a vibrating plate. Since then and to this date, the prevailing view has been that the particle motion out of nodal lines is random, implying uncontrollability. But how random really is the out-of-nodal-lines motion on a Chladni plate? Here we show that the motion is sufficiently regular to be statistically modelled, predicted and controlled. By playing carefully selected musical notes, we can control the position of multiple objects simultaneously and independently using a single acoustic actuator. Our method allows independent trajectory following, pattern transformation and sorting of multiple miniature objects in a wide range of materials, including electronic components, water droplets loaded on solid carriers, plant seeds, candy balls and metal parts. PMID:27611347

  14. Controlling the motion of multiple objects on a Chladni plate.

    PubMed

    Zhou, Quan; Sariola, Veikko; Latifi, Kourosh; Liimatainen, Ville

    2016-09-09

    The origin of the idea of moving objects by acoustic vibration can be traced back to 1787, when Ernst Chladni reported the first detailed studies on the aggregation of sand onto nodal lines of a vibrating plate. Since then and to this date, the prevailing view has been that the particle motion out of nodal lines is random, implying uncontrollability. But how random really is the out-of-nodal-lines motion on a Chladni plate? Here we show that the motion is sufficiently regular to be statistically modelled, predicted and controlled. By playing carefully selected musical notes, we can control the position of multiple objects simultaneously and independently using a single acoustic actuator. Our method allows independent trajectory following, pattern transformation and sorting of multiple miniature objects in a wide range of materials, including electronic components, water droplets loaded on solid carriers, plant seeds, candy balls and metal parts.

  15. Controlling the motion of multiple objects on a Chladni plate

    NASA Astrophysics Data System (ADS)

    Zhou, Quan; Sariola, Veikko; Latifi, Kourosh; Liimatainen, Ville

    2016-09-01

    The origin of the idea of moving objects by acoustic vibration can be traced back to 1787, when Ernst Chladni reported the first detailed studies on the aggregation of sand onto nodal lines of a vibrating plate. Since then and to this date, the prevailing view has been that the particle motion out of nodal lines is random, implying uncontrollability. But how random really is the out-of-nodal-lines motion on a Chladni plate? Here we show that the motion is sufficiently regular to be statistically modelled, predicted and controlled. By playing carefully selected musical notes, we can control the position of multiple objects simultaneously and independently using a single acoustic actuator. Our method allows independent trajectory following, pattern transformation and sorting of multiple miniature objects in a wide range of materials, including electronic components, water droplets loaded on solid carriers, plant seeds, candy balls and metal parts.

  16. Motion and force control of multiple robotic manipulators

    NASA Technical Reports Server (NTRS)

    Wen, John T.; Kreutz-Delgado, Kenneth

    1992-01-01

    This paper addresses the motion and force control problem of multiple robot arms manipulating a cooperatively held object. A general control paradigm is introduced which decouples the motion and force control problems. For motion control, different control strategies are constructed based on the variables used as the control input in the controller design. There are three natural choices; acceleration of a generalized coordinate, arm tip force vectors, and the joint torques. The first two choices require full model information but produce simple models for the control design problem. The last choice results in a class of relatively model independent control laws by exploiting the Hamiltonian structure of the open loop system. The motion control only determines the joint torque to within a manifold, due to the multiple-arm kinematic constraint. To resolve the nonuniqueness of the joint torques, two methods are introduced. If the arm and object models are available, an optimization can be performed to best allocate the desired and effector control force to the joint actuators. The other possibility is to control the internal force about some set point. It is shown that effective force regulation can be achieved even if little model information is available.

  17. Motion and force control of multiple robotic manipulators

    NASA Technical Reports Server (NTRS)

    Wen, John T.; Kreutz-Delgado, Kenneth

    1992-01-01

    This paper addresses the motion and force control problem of multiple robot arms manipulating a cooperatively held object. A general control paradigm is introduced which decouples the motion and force control problems. For motion control, different control strategies are constructed based on the variables used as the control input in the controller design. There are three natural choices; acceleration of a generalized coordinate, arm tip force vectors, and the joint torques. The first two choices require full model information but produce simple models for the control design problem. The last choice results in a class of relatively model independent control laws by exploiting the Hamiltonian structure of the open loop system. The motion control only determines the joint torque to within a manifold, due to the multiple-arm kinematic constraint. To resolve the nonuniqueness of the joint torques, two methods are introduced. If the arm and object models are available, an optimization can be performed to best allocate the desired and effector control force to the joint actuators. The other possibility is to control the internal force about some set point. It is shown that effective force regulation can be achieved even if little model information is available.

  18. Hybrid Motion Planning with Multiple Destinations

    NASA Technical Reports Server (NTRS)

    Clouse, Jeffery

    1998-01-01

    In our initial proposal, we laid plans for developing a hybrid motion planning system that combines the concepts of visibility-based motion planning, artificial potential field based motion planning, evolutionary constrained optimization, and reinforcement learning. Our goal was, and still is, to produce a hybrid motion planning system that outperforms the best traditional motion planning systems on problems with dynamic environments. The proposed hybrid system will be in two parts the first is a global motion planning system and the second is a local motion planning system. The global system will take global information about the environment, such as the placement of the obstacles and goals, and produce feasible paths through those obstacles. We envision a system that combines the evolutionary-based optimization and visibility-based motion planning to achieve this end.

  19. Conflicting motion information impairs multiple object tracking.

    PubMed

    St Clair, Rebecca; Huff, Markus; Seiffert, Adriane E

    2010-04-28

    People can keep track of target objects as they move among identical distractors using only spatiotemporal information. We investigated whether or not participants use motion information during the moment-to-moment tracking of objects by adding motion to the texture of moving objects. The texture either remained static or moved relative to the object's direction of motion, either in the same direction, the opposite direction, or orthogonal to each object's trajectory. Results showed that, compared to the static texture condition, tracking performance was worse when the texture moved in the opposite direction of the object and better when the texture moved in the same direction as the object. Our results support the conclusion that motion information is used during the moment-to-moment tracking of objects. Motion information may either affect a representation of position or be used to periodically predict the future location of targets.

  20. Multiple-stage ambiguity in motion perception reveals global computation of local motion directions.

    PubMed

    Rider, Andrew T; Nishida, Shin'ya; Johnston, Alan

    2016-12-01

    The motion of a 1D image feature, such as a line, seen through a small aperture, or the small receptive field of a neural motion sensor, is underconstrained, and it is not possible to derive the true motion direction from a single local measurement. This is referred to as the aperture problem. How the visual system solves the aperture problem is a fundamental question in visual motion research. In the estimation of motion vectors through integration of ambiguous local motion measurements at different positions, conventional theories assume that the object motion is a rigid translation, with motion signals sharing a common motion vector within the spatial region over which the aperture problem is solved. However, this strategy fails for global rotation. Here we show that the human visual system can estimate global rotation directly through spatial pooling of locally ambiguous measurements, without an intervening step that computes local motion vectors. We designed a novel ambiguous global flow stimulus, which is globally as well as locally ambiguous. The global ambiguity implies that the stimulus is simultaneously consistent with both a global rigid translation and an infinite number of global rigid rotations. By the standard view, the motion should always be seen as a global translation, but it appears to shift from translation to rotation as observers shift fixation. This finding indicates that the visual system can estimate local vectors using a global rotation constraint, and suggests that local motion ambiguity may not be resolved until consistencies with multiple global motion patterns are assessed.

  1. Autoadaptive motion modelling for MR-based respiratory motion estimation.

    PubMed

    Baumgartner, Christian F; Kolbitsch, Christoph; McClelland, Jamie R; Rueckert, Daniel; King, Andrew P

    2017-01-01

    Respiratory motion poses significant challenges in image-guided interventions. In emerging treatments such as MR-guided HIFU or MR-guided radiotherapy, it may cause significant misalignments between interventional road maps obtained pre-procedure and the anatomy during the treatment, and may affect intra-procedural imaging such as MR-thermometry. Patient specific respiratory motion models provide a solution to this problem. They establish a correspondence between the patient motion and simpler surrogate data which can be acquired easily during the treatment. Patient motion can then be estimated during the treatment by acquiring only the simpler surrogate data. In the majority of classical motion modelling approaches once the correspondence between the surrogate data and the patient motion is established it cannot be changed unless the model is recalibrated. However, breathing patterns are known to significantly change in the time frame of MR-guided interventions. Thus, the classical motion modelling approach may yield inaccurate motion estimations when the relation between the motion and the surrogate data changes over the duration of the treatment and frequent recalibration may not be feasible. We propose a novel methodology for motion modelling which has the ability to automatically adapt to new breathing patterns. This is achieved by choosing the surrogate data in such a way that it can be used to estimate the current motion in 3D as well as to update the motion model. In particular, in this work, we use 2D MR slices from different slice positions to build as well as to apply the motion model. We implemented such an autoadaptive motion model by extending our previous work on manifold alignment. We demonstrate a proof-of-principle of the proposed technique on cardiac gated data of the thorax and evaluate its adaptive behaviour on realistic synthetic data containing two breathing types generated from 6 volunteers, and real data from 4 volunteers. On synthetic data

  2. Students' Mathematical Modeling of Motion

    ERIC Educational Resources Information Center

    Marshall, Jill A.; Carrejo, David J.

    2008-01-01

    We present results of an investigation of university students' development of mathematical models of motion in a physical science course for preservice teachers and graduate students in science and mathematics education. Although some students were familiar with the standard concepts of position, velocity, and acceleration from physics classes,…

  3. Study of correlations in molecular motion by multiple quantum NMR

    NASA Astrophysics Data System (ADS)

    Tang, J. H.

    1981-11-01

    The theoretical background of spin Hamiltonians, the density matrix formalism of multiple quantum NMR are discussed as well as creation and detection of multiple quantum coherence by multiple pulse sequence. Prototype multiple quantum spectra of oriented benzene are presented. Redfield relaxation theory and the application of multiple quantum NMR to the study of correlations in fluctuations are considered. An oriented methyl group relaxed by paramagnetic impurities is examined and possible correlated motion between two coupled methyl groups is investigated by multiple quantum NMR. For a six spin system it is shown that the four quantum spectrum is sensitive to two body correlations, and serves a ready test of correlated motion. The spin lattice dynamics of orienting or tunneling methyl groups (CH3 and CD3) at low temperatures and the anisotropic spin lattice relaxation of deuterated hexamethylbenzene, caused by the sixfold reorientation of the molecules are described as well as NMR spectrometers.

  4. ITRF2014 plate motion model

    NASA Astrophysics Data System (ADS)

    Altamimi, Zuheir; Métivier, Laurent; Rebischung, Paul; Rouby, Hélène; Collilieux, Xavier

    2017-06-01

    For various geodetic and geophysical applications, users need to have access to a plate motion model (PMM) that is consistent with the ITRF2014 frame. This paper describes the approach used for determining a PMM from the horizontal velocities of a subset of the ITRF2014 sites away from plate boundaries, Glacial Isostatic Adjustment regions and other deforming zones. In theory it would be necessary to include in the inversion model a translational motion vector (called in this paper origin rate bias, ORB) that would represent the relative motion between the ITRF2014 origin (long-term averaged centre of mass of the Earth as sensed by SLR) and the centre of tectonic plate motion. We show that in practice, the magnitude of the estimated ORB is strongly dependent on the selection of ITRF2014 sites used for the PMM adjustment. Its Z-component can in particular range between 0 and more than 1 mm yr-1 depending on the station network used, preventing any geophysical interpretation of the estimated value. Relying on rigorous statistical criteria, the site selection finally adopted for the ITRF2014-PMM adjustment leads to a relatively small ORB (0.30 ± 0.18 mm yr-1 in the Z-component), which is statistically insignificant at the 2-sigma level, but also according to an F-ratio test. Therefore we opted for an ITRF2014-PMM without estimating the ORB, which in turn accommodates geodetic applications that require access to the ITRF2014 frame through pure plate rotation poles.

  5. Optimal displacement in apparent motion and quadrature models of motion sensing

    NASA Technical Reports Server (NTRS)

    Watson, Andrew B.

    1990-01-01

    A grating appears to move if it is displaced by some amount between two brief presentations, or between multiple successive presentations. A number of recent experiments have examined the influence of displacement size upon either the sensitivity to motion, or upon the induced motion aftereffect. Several recent motion models are based upon quadrature filters that respond in opposite quadrants in the spatiotemporal frequency plane. Predictions of the quadrature model are derived for both two-frame and multiframe displays. Quadrature models generally predict an optimal displacement of 1/4 cycle for two-frame displays, but in the multiframe case the prediction depends entirely on the frame rate.

  6. Development of a human body finite element model with multiple muscles and their controller for estimating occupant motions and impact responses in frontal crash situations.

    PubMed

    Iwamoto, Masami; Nakahira, Yuko; Kimpara, Hideyuki; Sugiyama, Takahiko; Min, Kyuengbo

    2012-10-01

    A few reports suggest differences in injury outcomes between cadaver tests and real-world accidents under almost similar conditions. This study hypothesized that muscle activity could primarily cause the differences, and then developed a human body finite element (FE) model with individual muscles. Each muscle was modeled as a hybrid model of bar elements with active properties and solid elements with passive properties. The model without muscle activation was firstly validated against five series of cadaver test data on impact responses in the anterior-posterior direction. The model with muscle activation levels estimated based on electromyography (EMG) data was secondly validated against four series of volunteer test data on bracing effects for stiffness and thickness of an upper arm muscle, and braced driver's responses under a static environment and a brake deceleration. A muscle controller using reinforcement learning (RL), which is a mathematical model of learning process in the basal ganglia associated with human postural controls, were newly proposed to estimate muscle activity in various occupant conditions including inattentive and attentive conditions. Control of individual muscles predicted by RL reproduced more human like head-neck motions than conventional control of two groups of agonist and antagonist muscles. The model and the controller demonstrated that head-neck motions of an occupant under an impact deceleration of frontal crash were different in between a bracing condition with maximal braking force and an occupant condition predicted by RL. The model and the controller have the potential to investigate muscular effects in various occupant conditions during frontal crashes.

  7. Self-Motion Impairs Multiple-Object Tracking

    ERIC Educational Resources Information Center

    Thomas, Laura E.; Seiffert, Adriane E.

    2010-01-01

    Investigations of multiple-object tracking aim to further our understanding of how people perform common activities such as driving in traffic. However, tracking tasks in the laboratory have overlooked a crucial component of much real-world object tracking: self-motion. We investigated the hypothesis that keeping track of one's own movement…

  8. Self-Motion Impairs Multiple-Object Tracking

    ERIC Educational Resources Information Center

    Thomas, Laura E.; Seiffert, Adriane E.

    2010-01-01

    Investigations of multiple-object tracking aim to further our understanding of how people perform common activities such as driving in traffic. However, tracking tasks in the laboratory have overlooked a crucial component of much real-world object tracking: self-motion. We investigated the hypothesis that keeping track of one's own movement…

  9. Study of correlations in molecular motion by multiple quantum NMR

    SciTech Connect

    Tang, J.H.

    1981-11-01

    Nuclear magnetic resonance is a very useful tool for characterizing molecular configurations through the measurement of transition frequencies and dipolar couplings. The measurement of spectral lineshapes, spin-lattice relaxation times, and transverse relaxation times also provide us with valuable information about correlations in molecular motion. The new technique of multiple quantum nuclear magnetic resonance has numerous advantages over the conventional single quantum NMR techniques in obtaining information about static and dynamic interactions of coupled spin systems. In the first two chapters, the theoretical background of spin Hamiltonians and the density matrix formalism of multiple quantum NMR is discussed. The creation and detection of multiple quantum coherence by multiple pulse sequence are discussed. Prototype multiple quantum spectra of oriented benzene are presented. Redfield relaxation theory and the application of multiple quantum NMR to the study of correlations in fluctuations are presented. A specific example of an oriented methyl group relaxed by paramagnetic impurities is studied in detail. The study of possible correlated motion between two coupled methyl groups by multiple quantum NMR is presented. For a six spin system it is shown that the four-quantum spectrum is sensitive to two-body correlations, and serves a ready test of correlated motion. The study of the spin-lattice dynamics of orienting or tunneling methyl groups (CH/sub 3/ and CD/sub 3/) at low temperatures is presented. The anisotropic spin-lattice relaxation of deuterated hexamethylbenzene, caused by the sixfold reorientation of the molecules, is investigated, and the NMR spectrometers and other experimental details are discussed.

  10. Fusion of multiple sensor imagery based on target motion characteristics

    NASA Astrophysics Data System (ADS)

    Tsao, Tien-Ren; Libert, John M.

    1991-08-01

    Fusion of multiple sensor imagery is an effective approach to clutter rejection in target detection and recognition. However, image registration at the pixel level and even at the feature level poses significant problems. We are developing a neural network computational schemes that will permit fusion of multiple sensor information according to target motion characteristics. One such scheme implements the Law of Common Fate to differentiate moving targets from dynamic background clutter on the basis of homogeneous velocity; spatiotemporal frequency analysis is applied to time-varying sensor imagery to detect and locate individual moving objects. Another computational scheme applies Gabor filters and differential Gabor filters to calculate image flow and then employs a Lie group-based neural network to interpret the 2D image flow in terms of 3D motion, and to delineate regions of homogeneous 3D motion; the motion-keyed regions may be correlated among sensor types to associate multiattribute information with the individual targets in the scene and to exclude clutter.

  11. Multiple-time-scale motion in molecularly linked nanoparticle arrays.

    PubMed

    George, Christopher; Szleifer, Igal; Ratner, Mark

    2013-01-22

    We explore the transport of electrons between electrodes that encase a two-dimensional array of metallic quantum dots linked by molecular bridges (such as α,ω alkaline dithiols). Because the molecules can move at finite temperatures, the entire transport structure comprising the quantum dots and the molecules is in dynamical motion while the charge is being transported. There are then several physical processes (physical excursions of molecules and quantum dots, electronic migration, ordinary vibrations), all of which influence electronic transport. Each can occur on a different time scale. It is therefore not appropriate to use standard approaches to this sort of electron transfer problem. Instead, we present a treatment in which three different theoretical approaches-kinetic Monte Carlo, classical molecular dynamics, and quantum transport-are all employed. In certain limits, some of the dynamical effects are unimportant. But in general, the transport seems to follow a sort of dynamic bond percolation picture, an approach originally introduced as formal models and later applied to polymer electrolytes. Different rate-determining steps occur in different limits. This approach offers a powerful scheme for dealing with multiple time scale transport problems, as will exist in many situations with several pathways through molecular arrays or even individual molecules that are dynamically disordered.

  12. Animal models in motion sickness research

    NASA Technical Reports Server (NTRS)

    Daunton, Nancy G.

    1990-01-01

    Practical information on candidate animal models for motion sickness research and on methods used to elicit and detect motion sickness in these models is provided. Four good potential models for use in motion sickness experiments include the dog, cat, squirrel monkey, and rat. It is concluded that the appropriate use of the animal models, combined with exploitation of state-of-the-art biomedical techniques, should generate a great step forward in the understanding of motion sickness mechanisms and in the development of efficient and effective approaches to its prevention and treatment in humans.

  13. Animal models in motion sickness research

    NASA Technical Reports Server (NTRS)

    Daunton, Nancy G.

    1990-01-01

    Practical information on candidate animal models for motion sickness research and on methods used to elicit and detect motion sickness in these models is provided. Four good potential models for use in motion sickness experiments include the dog, cat, squirrel monkey, and rat. It is concluded that the appropriate use of the animal models, combined with exploitation of state-of-the-art biomedical techniques, should generate a great step forward in the understanding of motion sickness mechanisms and in the development of efficient and effective approaches to its prevention and treatment in humans.

  14. Motion sickness: a negative reinforcement model.

    PubMed

    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.

  15. Reliability of psychophysiological responses across multiple motion sickness stimulation tests

    NASA Technical Reports Server (NTRS)

    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.

  16. Motion models in attitude estimation

    NASA Technical Reports Server (NTRS)

    Chu, D.; Wheeler, Z.; Sedlak, J.

    1994-01-01

    Attitude estimator use observations from different times to reduce the effects of noise. If the vehicle is rotating, the attitude at one time needs to be propagated to that at another time. If the vehicle measures its angular velocity, attitude propagating entails integrating a rotational kinematics equation only. If a measured angular velocity is not available, torques can be computed and an additional rotational dynamics equation integrated to give the angular velocity. Initial conditions for either of these integrations come from the estimation process. Sometimes additional quantities, such as gyro and torque parameters, are also solved for. Although the partial derivatives of attitude with respect to initial attitude and gyro parameters are well known, the corresponding partial derivatives with respect to initial angular velocity and torque parameters are less familiar. They can be derived and computed numerically in a way that is analogous to that used for the initial attitude and gyro parameters. Previous papers have demonstrated the feasibility of using dynamics models for attitude estimation but have not provided details of how each angular velocity and torque parameters can be estimated. This tutorial paper provides some of that detail, notably how to compute the state transition matrix when closed form expressions are not available. It also attempts to put dynamics estimation in perspective by showing the progression from constant to gyro-propagated to dynamics-propagated attitude motion models. Readers not already familiar with attitude estimation will find this paper an introduction to the subject, and attitude specialists may appreciate the collection of heretofore scattered results brought together in a single place.

  17. Modeling repetitive motions using structured light.

    PubMed

    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.

  18. A model of motion transparency processing with local center-surround interactions and feedback.

    PubMed

    Raudies, Florian; Mingolla, Ennio; Neumann, Heiko

    2011-11-01

    Motion transparency occurs when multiple coherent motions are perceived in one spatial location. Imagine, for instance, looking out of the window of a bus on a bright day, where the world outside the window is passing by and movements of passengers inside the bus are reflected in the window. The overlay of both motions at the window leads to motion transparency, which is challenging to process. Noisy and ambiguous motion signals can be reduced using a competition mechanism for all encoded motions in one spatial location. Such a competition, however, leads to the suppression of multiple peak responses that encode different motions, as only the strongest response tends to survive. As a solution, we suggest a local center-surround competition for population-encoded motion directions and speeds. Similar motions are supported, and dissimilar ones are separated, by representing them as multiple activations, which occurs in the case of motion transparency. Psychophysical findings, such as motion attraction and repulsion for motion transparency displays, can be explained by this local competition. Besides this local competition mechanism, we show that feedback signals improve the processing of motion transparency. A discrimination task for transparent versus opaque motion is simulated, where motion transparency is generated by superimposing large field motion patterns of either varying size or varying coherence of motion. The model's perceptual thresholds with and without feedback are calculated. We demonstrate that initially weak peak responses can be enhanced and stabilized through modulatory feedback signals from higher stages of processing.

  19. Ground Motion Modeling in the Eastern Caucasus

    NASA Astrophysics Data System (ADS)

    Pitarka, Arben; Gok, Rengin; Yetirmishli, Gurban; Ismayilova, Saida; Mellors, Robert

    2016-08-01

    In this study, we analyzed the performance of a preliminary three-dimensional (3D) velocity model of the Eastern Caucasus covering most of the Azerbaijan. The model was developed in support to long-period ground motion simulations and seismic hazard assessment from regional earthquakes in Azerbaijan. The model's performance was investigated by simulating ground motion from the damaging Mw 5.9, 2012 Zaqatala earthquake, which was well recorded throughout the region by broadband seismic instruments. In our simulations, we use a parallelized finite-difference method of fourth-order accuracy. The comparison between the simulated and recorded ground motion velocity in the modeled period range of 3-20 s shows that in general, the 3D velocity model performs well. Areas in which the model needs improvements are located mainly in the central part of the Kura basin and in the Caspian Sea coastal areas. Comparisons of simulated ground motion using our 3D velocity model and corresponding 1D regional velocity model were used to locate areas with strong 3D wave propagation effects. In areas with complex underground structure, the 1D model fails to produce the observed ground motion amplitude and duration, and spatial extend of ground motion amplification caused by wave propagation effects.

  20. Ground Motion Modeling in the Eastern Caucasus

    DOE PAGES

    Pitarka, Arben; Gok, Rengin; Yetirmishli, Gurban; ...

    2016-05-13

    In this paper, we analyzed the performance of a preliminary three-dimensional (3D) velocity model of the Eastern Caucasus covering most of the Azerbaijan. The model was developed in support to long-period ground motion simulations and seismic hazard assessment from regional earthquakes in Azerbaijan. The model’s performance was investigated by simulating ground motion from the damaging Mw 5.9, 2012 Zaqatala earthquake, which was well recorded throughout the region by broadband seismic instruments. In our simulations, we use a parallelized finite-difference method of fourth-order accuracy. The comparison between the simulated and recorded ground motion velocity in the modeled period range of 3–20more » s shows that in general, the 3D velocity model performs well. Areas in which the model needs improvements are located mainly in the central part of the Kura basin and in the Caspian Sea coastal areas. Comparisons of simulated ground motion using our 3D velocity model and corresponding 1D regional velocity model were used to locate areas with strong 3D wave propagation effects. In areas with complex underground structure, the 1D model fails to produce the observed ground motion amplitude and duration, and spatial extend of ground motion amplification caused by wave propagation effects.« less

  1. EEG-fMRI Gradient Artifact Correction by Multiple Motion-Related Templates.

    PubMed

    LeVan, Pierre; Zhang, Shuoyue; Knowles, Benjamin; Zaitsev, Maxim; Hennig, Jurgen

    2016-12-01

    In simultaneous electroencephalography (EEG) and functional magnetic resonance imaging (fMRI), artifacts on the EEG arise from the switching of magnetic field gradients in the MR scanner. These artifacts depend on head position, and are, therefore, difficult to remove in the presence of subject motion. In this study, gradient artifacts are modeled by multiple templates extracted from externally recorded motion information. Gradient artifact correction was performed in EEG-fMRI recordings by estimating artifactual templates modulated by slowly varying splines, as well as head position information. The EEG signal quality was then compared following two common methods: averaged artifact subtraction (AAS) and optimal basis sets (OBS). Artifact correction using multiple templates estimated from splines or motion time courses outperformed the existing AAS and OBS approaches, as quantified by root-mean-square power across gradient epochs. Improvements were mostly seen in posterior EEG channels, where most of the residual artifacts are seen following the AAS and OBS methods. Residual spectral power was comparable to that of EEG signals recorded without fMRI scanning. Gradient artifacts can be well modeled by multiple templates estimated from head position information, resulting in an effective artifact removal. This method can facilitate EEG-fMRI of uncooperative subjects in whom motion is inevitable, for example, to investigate high-frequency EEG activity in which gradient artifacts are particularly prominent.

  2. Neurons compute internal models of the physical laws of motion.

    PubMed

    Angelaki, Dora E; Shaikh, Aasef G; Green, Andrea M; Dickman, J David

    2004-07-29

    A critical step in self-motion perception and spatial awareness is the integration of motion cues from multiple sensory organs that individually do not provide an accurate representation of the physical world. One of the best-studied sensory ambiguities is found in visual processing, and arises because of the inherent uncertainty in detecting the motion direction of an untextured contour moving within a small aperture. A similar sensory ambiguity arises in identifying the actual motion associated with linear accelerations sensed by the otolith organs in the inner ear. These internal linear accelerometers respond identically during translational motion (for example, running forward) and gravitational accelerations experienced as we reorient the head relative to gravity (that is, head tilt). Using new stimulus combinations, we identify here cerebellar and brainstem motion-sensitive neurons that compute a solution to the inertial motion detection problem. We show that the firing rates of these populations of neurons reflect the computations necessary to construct an internal model representation of the physical equations of motion.

  3. Volumetric display containing multiple two-dimensional color motion pictures

    NASA Astrophysics Data System (ADS)

    Hirayama, R.; Shiraki, A.; Nakayama, H.; Kakue, T.; Shimobaba, T.; Ito, T.

    2014-06-01

    We have developed an algorithm which can record multiple two-dimensional (2-D) gradated projection patterns in a single three-dimensional (3-D) object. Each recorded pattern has the individual projected direction and can only be seen from the direction. The proposed algorithm has two important features: the number of recorded patterns is theoretically infinite and no meaningful pattern can be seen outside of the projected directions. In this paper, we expanded the algorithm to record multiple 2-D projection patterns in color. There are two popular ways of color mixing: additive one and subtractive one. Additive color mixing used to mix light is based on RGB colors and subtractive color mixing used to mix inks is based on CMY colors. We made two coloring methods based on the additive mixing and subtractive mixing. We performed numerical simulations of the coloring methods, and confirmed their effectiveness. We also fabricated two types of volumetric display and applied the proposed algorithm to them. One is a cubic displays constructed by light-emitting diodes (LEDs) in 8×8×8 array. Lighting patterns of LEDs are controlled by a microcomputer board. The other one is made of 7×7 array of threads. Each thread is illuminated by a projector connected with PC. As a result of the implementation, we succeeded in recording multiple 2-D color motion pictures in the volumetric displays. Our algorithm can be applied to digital signage, media art and so forth.

  4. Pancreatic Tumor Growth Prediction with Multiplicative Growth and Image-Derived Motion.

    PubMed

    Wong, Ken C L; Summers, Ronald M; Kebebew, Electron; Yao, Jianhua

    2015-01-01

    Pancreatic neuroendocrine tumors are abnormal growths of hormone-producing cells in the pancreas. Different from the brain in the skull, the pancreas in the abdomen can be largely deformed by the body posture and the surrounding organs. In consequence, both tumor growth and pancreatic motion attribute to the tumor shape difference observable from images. As images at different time points are used to personalize the tumor growth model, the prediction accuracy may be reduced if such motion is ignored. Therefore, we incorporate the image-derived pancreatic motion to tumor growth personalization. For realistic mechanical interactions, the multiplicative growth decomposition is used with a hyperelastic constitutive law to model tumor mass effect, which allows growth modeling without compromising the mechanical accuracy. With also the FDG-PET and contrast-enhanced CT images, the functional, structural, and motion data are combined for a more patient-specific model. Experiments on synthetic and clinical data show the importance of image-derived motion on estimating physiologically plausible mechanical properties and the promising performance of our framework. From six patient data sets, the recall, precision, Dice coefficient, relative volume difference, and average surface distance were 89.8 ± 3.5%, 85.6 ± 7.5%, 87.4 ± 3.6%, 9.7 ± 7.2%, and 0.6 ± 0.2 mm, respectively.

  5. Modeling absolute plate and plume motions

    NASA Astrophysics Data System (ADS)

    Bodinier, G. P.; Wessel, P.; Conrad, C. P.

    2016-12-01

    Paleomagnetic evidence for plume drift has made modeling of absolute plate motions challenging, especially since direct observations of plume drift are lacking. Predictions of plume drift arising from mantle convection models and broadly satisfying observed paleolatitudes have so far provided the only framework for deriving absolute plate motions over moving hotspots. However, uncertainties in mantle rheology, temperature, and initial conditions make such models nonunique. Using simulated and real data, we will show that age progressions along Pacific hotspot trails provide strong constraints on plume motions for all major trails, and furthermore that it is possible to derive models for relative plume drift from these data alone. Relative plume drift depends on the inter-hotspot distances derived from age progressions but lacks a fixed reference point and orientation. By incorporating paleolatitude histories for the Hawaii and Louisville chains we add further constraints on allowable plume motions, yet one unknown parameter remains: a longitude shift that applies equally to all plumes. To obtain a solution we could restrict either the Hawaii or Louisville plume to have latitudinal motion only, thus satisfying paleolatitude constraints. Yet, restricting one plume to latitudinal motion while all others move freely is not realistic. Consequently, it is only possible to resolve the motion of hotspots relative to an overall and unknown longitudinal shift as a function of time. Our plate motions are therefore dependent on the same shift via an unknown rotation about the north pole. Yet, as plume drifts are consequences of mantle convection, our results place strong constraints on the pattern of convection. Other considerations, such as imposed limits on plate speed, plume speed, proximity to LLSVP edges, model smoothness, or relative plate motions via ridge-spotting may add further constraints that allow a unique model of Pacific absolute plate and plume motions to be

  6. Motion control of the ankle joint with a multiple contact nerve cuff electrode: a simulation study.

    PubMed

    Park, Hyun-Joo; Durand, Dominique M

    2014-08-01

    The flat interface nerve electrode (FINE) has demonstrated significant capability for fascicular and subfascicular stimulation selectivity. However, due to the inherent complexity of the neuromuscular skeletal systems and nerve-electrode interface, a trajectory tracking motion control algorithm of musculoskeletal systems for functional electrical stimulation using a multiple contact nerve cuff electrode such as FINE has not yet been developed. In our previous study, a control system was developed for multiple-input multiple-output (MIMO) musculoskeletal systems with little prior knowledge of the system. In this study, more realistic computational ankle/subtalar joint model including a finite element model of the sciatic nerve was developed. The control system was tested to control the motion of ankle/subtalar joint angles by modulating the pulse amplitude of each contact of a FINE placed on the sciatic nerve. The simulation results showed that the control strategy based on the separation of steady state and dynamic properties of the system resulted in small output tracking errors for different reference trajectories such as sinusoidal and filtered random signals. The proposed control method also demonstrated robustness against external disturbances and system parameter variations such as muscle fatigue. These simulation results under various circumstances indicate that it is possible to take advantage of multiple contact nerve electrodes with spatial selectivity for the control of limb motion by peripheral nerve stimulation even with limited individual muscle selectivity. This technology could be useful to restore neural function in patients with paralysis.

  7. Modeling the polar motion of Titan

    NASA Astrophysics Data System (ADS)

    Coyette, Alexis; Van Hoolst, Tim; Baland, Rose-Marie; Tokano, Tetsuya

    2016-02-01

    The angular momentum of the atmosphere and of the hydrocarbon lakes of Titan have a large equatorial component that can excite polar motion, a variable orientation of the rotation axis of Titan with respect to its surface. We here use the angular momentum obtained from a General Circulation Model of the atmosphere of Titan and from an Ocean Circulation Model for Titan's polar lakes to model the polar motion of Titan as a function of the interior structure. Besides the gravitational torque exerted by Saturn on Titan's aspherical mass distribution, the rotational model also includes torques arising due to the presence of an ocean under a thin ice shell as well as the influence of the elasticity of the different layers. The Chandler wobble period of a solid and rigid Titan without its atmosphere is about 279 years. The period of the Chandler wobble is mainly influenced by the atmosphere of Titan (-166 years) and the presence of an internal global ocean (+135 to 295 years depending on the internal model) and to a lesser extent by the elastic deformations (+3.7 years). The forced polar motion of a solid and rigid Titan is elliptical with an amplitude of about 50 m and a main period equal to the orbital period of Saturn. It is mainly forced by the atmosphere of Titan while the lakes of Titan are at the origin of a displacement of the mean polar motion, or polar offset. The subsurface ocean can largely increase the polar motion amplitude due to resonant amplification with a wobble free mode of Titan. The amplitudes as well as the main periods of the polar motion depend on whether and which forcing period is close to the period of a free mode. For a thick ice shell, the polar motion mainly has an annual period and an amplitude of about 1 km. For thinner ice shells, the polar motion amplitude can reach several tens of km and shorter periods become dominant. We demonstrate that for thick ice shells, the ice shell rigidity weakly influences the amplitude of the polar motion

  8. Motion coordination and performance analysis of multiple vehicle systems

    NASA Astrophysics Data System (ADS)

    Sharma, Vikrant

    In this dissertation, issues related to multiple vehicle systems are studied. First, the issue of vehicular congestion is addressed and its effect on the performance of some systems studied. Motion coordination algorithms for some systems of interest are also developed. The issue of vehicular congestion is addressed by characterizing the effect of increasing the number of vehicles, in a bounded region, on the speed of the vehicles. A multiple vehicle routing problem is considered where vehicles are required to stay velocity-dependent distance away from each other to avoid physical collisions. Optimal solutions to the minimum time routing are characterized and are found to increase with the square root of the number of vehicles in the environment, for different distributions of the sources and destinations of the vehicles. The second issue addressed is that of the effect of vehicular congestion on the delay associated with data delivery in wireless networks where vehicles are used to transport data to increase the wireless capacity of the network. Tight bounds on the associated delay are derived. The next problem addressed is that of covering an arbitrary path-connected two dimensional region, using multiple unmanned aerial vehicles, in minimum time. A constant-factor optimal algorithm is presented for any given initial positions of the vehicles inside the environment. The last problem addressed is that of the deployment of an environment monitoring network of mobile sensors to improve the network lifetime and sensing quality. A distributed algorithm is presented that improves the system's performance starting from an initial deployment.

  9. Motion coordination of multiple autonomous vehicles in a spatiotemporal flowfield

    NASA Astrophysics Data System (ADS)

    Peterson, Cameron Kai

    The long-term goal of this research is to provide theoretically justified control strategies to operate autonomous vehicles in spatiotemporal flowfields. The specific objective of this dissertation is to use estimation and nonlinear control techniques to generate decentralized control algorithms that enable motion coordination for multiple autonomous vehicles while operating in a time-varying flowfield. A cooperating team of vehicles can benefit from sharing data and tasking responsibilities. Many existing control algorithms promote collaboration of autonomous vehicles. However, these algorithms often fail to account for the degradation of control performance caused by flowfields. This dissertation presents decentralized multivehicle coordination algorithms designed for operation in a spatially or temporally varying flowfield. Each vehicle is represented using a Newtonian particle traveling in a plane at constant speed relative to the flow and subject to a steering control. Initially, we assume the flowfield is known and describe algorithms that stabilize a circular formation in a time-varying spatially nonuniform flow of moderate intensity. These algorithms are extended by relaxing the assumption that the flow is known: the vehicles dynamically estimate the flow and use that estimate in the control. We propose a distributed estimation and control algorithm comprising a consensus filter to share information gleaned from noisy position measurements, and an information filter to reconstruct a spatially varying flowfield. The theoretical results are illustrated with numerical simulations of circular formation control and validated in outdoor unmanned aerial vehicle (UAV) flight tests.

  10. Development and Validation of the Total HUman Model for Safety (THUMS) Version 5 Containing Multiple 1D Muscles for Estimating Occupant Motions with Muscle Activation During Side Impacts.

    PubMed

    Iwamoto, Masami; Nakahira, Yuko

    2015-11-01

    Accurate prediction of occupant head kinematics is critical for better understanding of head/face injury mechanisms in side impacts, especially far-side occupants. In light of the fact that researchers have demonstrated that muscle activations, especially in neck muscles, can affect occupant head kinematics, a human body finite element (FE) model that considers muscle activation is useful for predicting occupant head kinematics in real-world automotive accidents. In this study, we developed a human body FE model called the THUMS (Total HUman Model for Safety) Version 5 that contains 262 one-dimensional (1D) Hill-type muscle models over the entire body. The THUMS was validated against 36 series of PMHS (Post Mortem Human Surrogate) and volunteer test data in this study, and 16 series of PMHS and volunteer test data on side impacts are presented. Validation results with force-time curves were also evaluated quantitatively using the CORA (CORrelation and Analysis) method. The validation results suggest that the THUMS has good biofidelity in the responses of the regional or full body for side impacts, but relatively poor biofidelity in its local level of responses such as brain displacements. Occupant kinematics predicted by the THUMS with a muscle controller using 22 PID (Proportional-Integral- Derivative) controllers were compared with those of volunteer test data on low-speed lateral impacts. The THUMS with muscle controller reproduced the head kinematics of the volunteer data more accurately than that without muscle activation, although further studies on validation of torso kinematics are needed for more accurate predictions of occupant head kinematics.

  11. It is time to integrate: the temporal dynamics of object motion and texture motion integration in multiple object tracking.

    PubMed

    Huff, Markus; Papenmeier, Frank

    2013-01-14

    In multiple-object tracking, participants can track several moving objects among identical distractors. It has recently been shown that the human visual system uses motion information in order to keep track of targets (St. Clair et al., Journal of Vision, 10(4), 1-13). Texture on the surface of an object that moved in the opposite direction to the object itself impaired tracking performance. In this study, we examined the temporal interval at which texture motion and object motion is integrated in dynamic scenes. In two multiple-object tracking experiments, we manipulated the texture motion on the objects: The texture either moved in the same direction as the objects, in the opposite direction, or alternated between the same and opposite direction at varying intervals. In Experiment 1, we show that the integration of object motion and texture motion can take place at intervals as short as 100 ms. In Experiment 2, we show that there is a linear relationship between the proportion of opposite texture motion and tracking performance. We suggest that texture motion might cause shifts in perceived object locations, thus influencing tracking performance.

  12. Locust Collective Motion and Its Modeling

    PubMed Central

    Ariel, Gil; Ayali, Amir

    2015-01-01

    Over the past decade, technological advances in experimental and animal tracking techniques have motivated a renewed theoretical interest in animal collective motion and, in particular, locust swarming. This review offers a comprehensive biological background followed by comparative analysis of recent models of locust collective motion, in particular locust marching, their settings, and underlying assumptions. We describe a wide range of recent modeling and simulation approaches, from discrete agent-based models of self-propelled particles to continuous models of integro-differential equations, aimed at describing and analyzing the fascinating phenomenon of locust collective motion. These modeling efforts have a dual role: The first views locusts as a quintessential example of animal collective motion. As such, they aim at abstraction and coarse-graining, often utilizing the tools of statistical physics. The second, which originates from a more biological perspective, views locust swarming as a scientific problem of its own exceptional merit. The main goal should, thus, be the analysis and prediction of natural swarm dynamics. We discuss the properties of swarm dynamics using the tools of statistical physics, as well as the implications for laboratory experiments and natural swarms. Finally, we stress the importance of a combined-interdisciplinary, biological-theoretical effort in successfully confronting the challenges that locusts pose at both the theoretical and practical levels. PMID:26656851

  13. Crosstalk and transitions between multiple spatial maps in an attractor neural network model of the hippocampus: Collective motion of the activity

    NASA Astrophysics Data System (ADS)

    Monasson, R.; Rosay, S.

    2014-03-01

    The dynamics of a neural model for hippocampal place cells storing spatial maps is studied. In the absence of external input, depending on the number of cells and on the values of control parameters (number of environments stored, level of neural noise, average level of activity, connectivity of place cells), a "clump" of spatially localized activity can diffuse or remains pinned due to crosstalk between the environments. In the single-environment case, the macroscopic coefficient of diffusion of the clump and its effective mobility are calculated analytically from first principles and corroborated by numerical simulations. In the multienvironment case the heights and the widths of the pinning barriers are analytically characterized with the replica method; diffusion within one map is then in competition with transitions between different maps. Possible mechanisms enhancing mobility are proposed and tested.

  14. Mathematical modelling of submarine landslide motion

    NASA Astrophysics Data System (ADS)

    Burminskij, A.

    2012-04-01

    Mathematical modelling of submarine landslide motion The paper presents a mathematical model to calculate dynamic parameters of a submarine landslide. The problem of estimation possible submarine landslides dynamic parameters and run-out distances as well as their effect on submarine structures becomes more and more actual because they can have significant impacts on infrastructure such as the rupture of submarine cables and pipelines, damage to offshore drilling platforms, cause a tsunami. In this paper a landslide is considered as a viscoplastic flow and is described by continuum mechanics equations, averaged over the flow depth. The model takes into account friction at the bottom and at the landslide-water boundary, as well as the involvement of bottom material in motion. A software was created and series of test calculations were performed. Calculations permitted to estimate the contribution of various model coefficients and initial conditions. Motion down inclined bottom was studied both for constant and variable slope angle. Examples of typical distributions of the flow velocity, thickness and density along the landslide body at different stages of motion are given.

  15. Learning about Locomotion Patterns: Effective Use of Multiple Pictures and Motion-Indicating Arrows

    ERIC Educational Resources Information Center

    Imhof, Birgit; Scheiter, Katharina; Edelmann, Jorg; Gerjets, Peter

    2013-01-01

    This study investigated how enriching visualizations with arrows indicating the motion of objects may help in conveying dynamic information: Multiple static-simultaneous visualizations with motion-indicating arrows were compared with either multiple visualizations without arrows or a single visualization with arrows. Seventy-one students were…

  16. Learning about Locomotion Patterns: Effective Use of Multiple Pictures and Motion-Indicating Arrows

    ERIC Educational Resources Information Center

    Imhof, Birgit; Scheiter, Katharina; Edelmann, Jorg; Gerjets, Peter

    2013-01-01

    This study investigated how enriching visualizations with arrows indicating the motion of objects may help in conveying dynamic information: Multiple static-simultaneous visualizations with motion-indicating arrows were compared with either multiple visualizations without arrows or a single visualization with arrows. Seventy-one students were…

  17. Multiple Indicators, Multiple Causes Measurement Error Models

    PubMed Central

    Tekwe, Carmen D.; Carter, Randy L.; Cullings, Harry M.; Carroll, Raymond J.

    2014-01-01

    Multiple Indicators, Multiple Causes Models (MIMIC) are often employed by researchers studying the effects of an unobservable latent variable on a set of outcomes, when causes of the latent variable are observed. There are times however when the causes of the latent variable are not observed because measurements of the causal variable are contaminated by measurement error. The objectives of this paper are: (1) to develop a novel model by extending the classical linear MIMIC model to allow both Berkson and classical measurement errors, defining the MIMIC measurement error (MIMIC ME) model, (2) to develop likelihood based estimation methods for the MIMIC ME model, (3) to apply the newly defined MIMIC ME model to atomic bomb survivor data to study the impact of dyslipidemia and radiation dose on the physical manifestations of dyslipidemia. As a by-product of our work, we also obtain a data-driven estimate of the variance of the classical measurement error associated with an estimate of the amount of radiation dose received by atomic bomb survivors at the time of their exposure. PMID:24962535

  18. Multiple indicators, multiple causes measurement error models

    SciTech Connect

    Tekwe, Carmen D.; Carter, Randy L.; Cullings, Harry M.; Carroll, Raymond J.

    2014-06-25

    Multiple indicators, multiple causes (MIMIC) models are often employed by researchers studying the effects of an unobservable latent variable on a set of outcomes, when causes of the latent variable are observed. There are times, however, when the causes of the latent variable are not observed because measurements of the causal variable are contaminated by measurement error. The objectives of this study are as follows: (i) to develop a novel model by extending the classical linear MIMIC model to allow both Berkson and classical measurement errors, defining the MIMIC measurement error (MIMIC ME) model; (ii) to develop likelihood-based estimation methods for the MIMIC ME model; and (iii) to apply the newly defined MIMIC ME model to atomic bomb survivor data to study the impact of dyslipidemia and radiation dose on the physical manifestations of dyslipidemia. Finally, as a by-product of our work, we also obtain a data-driven estimate of the variance of the classical measurement error associated with an estimate of the amount of radiation dose received by atomic bomb survivors at the time of their exposure.

  19. Multiple indicators, multiple causes measurement error models

    DOE PAGES

    Tekwe, Carmen D.; Carter, Randy L.; Cullings, Harry M.; ...

    2014-06-25

    Multiple indicators, multiple causes (MIMIC) models are often employed by researchers studying the effects of an unobservable latent variable on a set of outcomes, when causes of the latent variable are observed. There are times, however, when the causes of the latent variable are not observed because measurements of the causal variable are contaminated by measurement error. The objectives of this study are as follows: (i) to develop a novel model by extending the classical linear MIMIC model to allow both Berkson and classical measurement errors, defining the MIMIC measurement error (MIMIC ME) model; (ii) to develop likelihood-based estimation methodsmore » for the MIMIC ME model; and (iii) to apply the newly defined MIMIC ME model to atomic bomb survivor data to study the impact of dyslipidemia and radiation dose on the physical manifestations of dyslipidemia. Finally, as a by-product of our work, we also obtain a data-driven estimate of the variance of the classical measurement error associated with an estimate of the amount of radiation dose received by atomic bomb survivors at the time of their exposure.« less

  20. Multiple indicators, multiple causes measurement error models.

    PubMed

    Tekwe, Carmen D; Carter, Randy L; Cullings, Harry M; Carroll, Raymond J

    2014-11-10

    Multiple indicators, multiple causes (MIMIC) models are often employed by researchers studying the effects of an unobservable latent variable on a set of outcomes, when causes of the latent variable are observed. There are times, however, when the causes of the latent variable are not observed because measurements of the causal variable are contaminated by measurement error. The objectives of this paper are as follows: (i) to develop a novel model by extending the classical linear MIMIC model to allow both Berkson and classical measurement errors, defining the MIMIC measurement error (MIMIC ME) model; (ii) to develop likelihood-based estimation methods for the MIMIC ME model; and (iii) to apply the newly defined MIMIC ME model to atomic bomb survivor data to study the impact of dyslipidemia and radiation dose on the physical manifestations of dyslipidemia. As a by-product of our work, we also obtain a data-driven estimate of the variance of the classical measurement error associated with an estimate of the amount of radiation dose received by atomic bomb survivors at the time of their exposure. Copyright © 2014 John Wiley & Sons, Ltd.

  1. Stochastic models for cell motion and taxis.

    PubMed

    Ionides, Edward L; Fang, Kathy S; Isseroff, R Rivkah; Oster, George F

    2004-01-01

    Certain biological experiments investigating cell motion result in time lapse video microscopy data which may be modeled using stochastic differential equations. These models suggest statistics for quantifying experimental results and testing relevant hypotheses, and carry implications for the qualitative behavior of cells and for underlying biophysical mechanisms. Directional cell motion in response to a stimulus, termed taxis, has previously been modeled at a phenomenological level using the Keller-Segel diffusion equation. The Keller-Segel model cannot distinguish certain modes of taxis, and this motivates the introduction of a richer class of models which is nevertheless still amenable to statistical analysis. A state space model formulation is used to link models proposed for cell velocity to observed data. Sequential Monte Carlo methods enable parameter estimation via maximum likelihood for a range of applicable models. One particular experimental situation, involving the effect of an electric field on cell behavior, is considered in detail. In this case, an Ornstein- Uhlenbeck model for cell velocity is found to compare favorably with a nonlinear diffusion model.

  2. Mathematical modelling of animate and intentional motion.

    PubMed Central

    Rittscher, Jens; Blake, Andrew; Hoogs, Anthony; Stein, Gees

    2003-01-01

    Our aim is to enable a machine to observe and interpret the behaviour of others. Mathematical models are employed to describe certain biological motions. The main challenge is to design models that are both tractable and meaningful. In the first part we will describe how computer vision techniques, in particular visual tracking, can be applied to recognize a small vocabulary of human actions in a constrained scenario. Mainly the problems of viewpoint and scale invariance need to be overcome to formalize a general framework. Hence the second part of the article is devoted to the question whether a particular human action should be captured in a single complex model or whether it is more promising to make extensive use of semantic knowledge and a collection of low-level models that encode certain motion primitives. Scene context plays a crucial role if we intend to give a higher-level interpretation rather than a low-level physical description of the observed motion. A semantic knowledge base is used to establish the scene context. This approach consists of three main components: visual analysis, the mapping from vision to language and the search of the semantic database. A small number of robust visual detectors is used to generate a higher-level description of the scene. The approach together with a number of results is presented in the third part of this article. PMID:12689374

  3. Modelling fast forms of visual neural plasticity using a modified second-order motion energy model.

    PubMed

    Pavan, Andrea; Contillo, Adriano; Mather, George

    2014-12-01

    The Adelson-Bergen motion energy sensor is well established as the leading model of low-level visual motion sensing in human vision. However, the standard model cannot predict adaptation effects in motion perception. A previous paper Pavan et al.(Journal of Vision 10:1-17, 2013) presented an extension to the model which uses a first-order RC gain-control circuit (leaky integrator) to implement adaptation effects which can span many seconds, and showed that the extended model's output is consistent with psychophysical data on the classic motion after-effect. Recent psychophysical research has reported adaptation over much shorter time periods, spanning just a few hundred milliseconds. The present paper further extends the sensor model to implement rapid adaptation, by adding a second-order RC circuit which causes the sensor to require a finite amount of time to react to a sudden change in stimulation. The output of the new sensor accounts accurately for psychophysical data on rapid forms of facilitation (rapid visual motion priming, rVMP) and suppression (rapid motion after-effect, rMAE). Changes in natural scene content occur over multiple time scales, and multi-stage leaky integrators of the kind proposed here offer a computational scheme for modelling adaptation over multiple time scales.

  4. Transverse Electron Motion and Multiple Electron Injection in Blowout Bubble of Laser Wakefield Accelerator

    NASA Astrophysics Data System (ADS)

    Matsuoka, T.; McGuffey, C.; Cummings, P. G.; Horovitz, Y.; Dollar, F.; Schumaker, W.; Chvykov, V.; Kalintchenko, G.; Rousseau, P.; Yanovsky, V.; Bulanov, S. S.; Thomas, A. G. R.; Maksimchuk, A.; Krushelnick, K.

    2010-11-01

    An analytical formula for electron motion in a spherical bubble was compared with data from electron acceleration experiments using the HERCULES laser system showing reasonable agreement. This also provides evidence for continuous injection of electrons into the bubble with multiple bunches in the bubble separated both transversely and longitudinally. The only free parameter in the analytical model was radius of the bubble (rb) which was found to be close to the matched spot size for self focusing. The RMS electron beam divergence is found to increase with bunch charge also suggesting tradeoff between beam divergence and photon number in applications for such beams as an x-ray source.

  5. Modelling motions within the organ of Corti

    NASA Astrophysics Data System (ADS)

    Ni, Guangjian; Baumgart, Johannes; Elliott, Stephen

    2015-12-01

    Most cochlear models used to describe the basilar membrane vibration along the cochlea are concerned with macromechanics, and often assume that the organ of Corti moves as a single unit, ignoring the individual motion of different components. New experimental technologies provide the opportunity to measure the dynamic behaviour of different components within the organ of Corti, but only for certain types of excitation. It is thus still difficult to directly measure every aspect of cochlear dynamics, particularly for acoustic excitation of the fully active cochlea. The present work studies the dynamic response of a model of the cross-section of the cochlea, at the microscopic level, using the finite element method. The elastic components are modelled with plate elements and the perilymph and endolymph are modelled with inviscid fluid elements. The individual motion of each component within the organ of Corti is calculated with dynamic pressure loading on the basilar membrane and the motions of the experimentally accessible parts are compared with measurements. The reticular lamina moves as a stiff plate, without much bending, and is pivoting around a point close to the region of the inner hair cells, as observed experimentally. The basilar membrane shows a slightly asymmetric mode shape, with maximum displacement occurring between the second-row and the third-row of the outer hair cells. The dynamics responses is also calculated, and compared with experiments, when driven by the outer hair cells. The receptance of the basilar membrane motion and of the deflection of the hair bundles of the outer hair cells is thus obtained, when driven either acoustically or electrically. In this way, the fully active linear response of the basilar membrane to acoustic excitation can be predicted by using a linear superposition of the calculated receptances and a defined gain function for the outer hair cell feedback.

  6. SU-E-J-186: Using 4DCT-Based Motion Modeling to Predict Motion and Duty Cycle On Successive Days of Gated Radiotherapy

    SciTech Connect

    Myronakis, M; Cai, W; Dhou, S; Cifter, F; Lewis, J

    2015-06-15

    Purpose: To determine if 4DCT-based motion modeling and external surrogate motion measured during treatment simulation can enhance prediction of residual tumor motion and duty cycle during treatment delivery. Methods: This experiment was conducted using simultaneously recorded tumor and external surrogate motion acquired over multiple fractions of lung cancer radiotherapy. These breathing traces were combined with the XCAT phantom to simulate CT images. Data from the first day was used to estimate the residual tumor motion and duty cycle both directly from the 4DCT (the current clinical standard), and from external-surrogate based motion modeling. The accuracy of these estimated residual tumor motions and duty cycles are evaluated by comparing to the measured internal/external motions from other treatment days. Results: All calculations were done for 25% and 50% duty cycles. The results indicated that duty cycle derived from 4DCT information alone is not enough to accurately predict duty cycles during treatment. Residual tumor motion was determined from the recorded data and compared with the estimated residual tumor motion from 4DCT. Relative differences in residual tumor motion varied from −30% to 55%, suggesting that more information is required to properly predict residual tumor motion. Compared to estimations made from 4DCT, in three out of four patients examined, the 30 seconds of motion modeling data was able to predict the duty cycle with better accuracy than 4DCT. No improvement was observed in prediction of residual tumor motion for this dataset. Conclusion: Motion modeling during simulation has the potential to enhance 4DCT and provide more information about target motion, duty cycles, and delivered dose. Based on these four patients, 30 seconds of motion modeling data produced improve duty cycle estimations but showed no measurable improvement in residual tumor motion prediction. More patient data is needed to verify this Result. I would like to

  7. Nonlinear-drifted Brownian motion with multiple hidden states for remaining useful life prediction of rechargeable batteries

    NASA Astrophysics Data System (ADS)

    Wang, Dong; Zhao, Yang; Yang, Fangfang; Tsui, Kwok-Leung

    2017-09-01

    Brownian motion with adaptive drift has attracted much attention in prognostics because its first hitting time is highly relevant to remaining useful life prediction and it follows the inverse Gaussian distribution. Besides linear degradation modeling, nonlinear-drifted Brownian motion has been developed to model nonlinear degradation. Moreover, the first hitting time distribution of the nonlinear-drifted Brownian motion has been approximated by time-space transformation. In the previous studies, the drift coefficient is the only hidden state used in state space modeling of the nonlinear-drifted Brownian motion. Besides the drift coefficient, parameters of a nonlinear function used in the nonlinear-drifted Brownian motion should be treated as additional hidden states of state space modeling to make the nonlinear-drifted Brownian motion more flexible. In this paper, a prognostic method based on nonlinear-drifted Brownian motion with multiple hidden states is proposed and then it is applied to predict remaining useful life of rechargeable batteries. 26 sets of rechargeable battery degradation samples are analyzed to validate the effectiveness of the proposed prognostic method. Moreover, some comparisons with a standard particle filter based prognostic method, a spherical cubature particle filter based prognostic method and two classic Bayesian prognostic methods are conducted to highlight the superiority of the proposed prognostic method. Results show that the proposed prognostic method has lower average prediction errors than the particle filter based prognostic methods and the classic Bayesian prognostic methods for battery remaining useful life prediction.

  8. The Effects of Towfish Motion on Sidescan Sonar Images: Extension to a Multiple-Beam Device

    DTIC Science & Technology

    1994-02-01

    Towfish Motion on Sidescan Sonar Images: Extension to a Multiple -Beam Device Acceso NTIS CRA&I S.D. Anstee u; ,-, o* , J.* ttiicatorn By "By...THE EFFECTS OF TOWFISH MOTION ON SIDESCAN SONAR IMAGES: EXTENSION TO A MULTIPLE -BEAM DEVICE S, S.D. ANSTEE 6 2 9 Nm MRL-TN-660 FEBRUARY 1994 Al DTIC...previously used to estimate the geometrical effects oftowjish motion on single-beam sidescan sonar images is modified to simulate a multiple -beam

  9. Anisotropic stellar models admitting conformal motion

    NASA Astrophysics Data System (ADS)

    Banerjee, Ayan; Banerjee, Sumita; Hansraj, Sudan; Ovgun, Ali

    2017-04-01

    We address the problem of finding static and spherically symmetric anisotropic compact stars in general relativity that admit conformal motions. The study is framed in the language of f( R) gravity theory in order to expose opportunity for further study in the more general theory. Exact solutions of compact stars are found under the assumption that spherically symmetric spacetimes admit conformal motion with anisotropic matter distribution in nature. In this work, two cases have been studied for the existence of such solutions: first, we consider the model given by f(R)=R and then f(R)=aR+b . Finally, specific characteristics and physical properties have been explored analytically along with graphical representations for conformally symmetric compact stars in f( R) gravity.

  10. A single unexpected change in target- but not distractor motion impairs multiple object tracking

    PubMed Central

    Meyerhoff, Hauke S.; Papenmeier, Frank; Jahn, Georg; Huff, Markus

    2013-01-01

    Recent research addresses the question whether motion information of multiple objects contributes to maintaining a selection of objects across a period of motion. Here, we investigate whether target and/or distractor motion information is used during attentive tracking. We asked participants to track four objects and changed either the motion direction of targets, the motion direction of distractors, neither, or both during a brief flash in the middle of a tracking interval. We observed that a single direction change of targets is sufficient to impair tracking performance. In contrast, changing the motion direction of distractors had no effect on performance. This indicates that target- but not distractor motion information is evaluated during tracking. PMID:23799190

  11. Multiple model inference.

    SciTech Connect

    Swiler, Laura Painton; Urbina, Angel

    2010-07-01

    This paper compares three approaches for model selection: classical least squares methods, information theoretic criteria, and Bayesian approaches. Least squares methods are not model selection methods although one can select the model that yields the smallest sum-of-squared error function. Information theoretic approaches balance overfitting with model accuracy by incorporating terms that penalize more parameters with a log-likelihood term to reflect goodness of fit. Bayesian model selection involves calculating the posterior probability that each model is correct, given experimental data and prior probabilities that each model is correct. As part of this calculation, one often calibrates the parameters of each model and this is included in the Bayesian calculations. Our approach is demonstrated on a structural dynamics example with models for energy dissipation and peak force across a bolted joint. The three approaches are compared and the influence of the log-likelihood term in all approaches is discussed.

  12. Strong ground motion simulation of the 2016 Kumamoto earthquake of April 16 using multiple point sources

    NASA Astrophysics Data System (ADS)

    Nagasaka, Yosuke; Nozu, Atsushi

    2017-02-01

    The pseudo point-source model approximates the rupture process on faults with multiple point sources for simulating strong ground motions. A simulation with this point-source model is conducted by combining a simple source spectrum following the omega-square model with a path spectrum, an empirical site amplification factor, and phase characteristics. Realistic waveforms can be synthesized using the empirical site amplification factor and phase models even though the source model is simple. The Kumamoto earthquake occurred on April 16, 2016, with M JMA 7.3. Many strong motions were recorded at stations around the source region. Some records were considered to be affected by the rupture directivity effect. This earthquake was suitable for investigating the applicability of the pseudo point-source model, the current version of which does not consider the rupture directivity effect. Three subevents (point sources) were located on the fault plane, and the parameters of the simulation were determined. The simulated results were compared with the observed records at K-NET and KiK-net stations. It was found that the synthetic Fourier spectra and velocity waveforms generally explained the characteristics of the observed records, except for underestimation in the low frequency range. Troughs in the observed Fourier spectra were also well reproduced by placing multiple subevents near the hypocenter. The underestimation is presumably due to the following two reasons. The first is that the pseudo point-source model targets subevents that generate strong ground motions and does not consider the shallow large slip. The second reason is that the current version of the pseudo point-source model does not consider the rupture directivity effect. Consequently, strong pulses were not reproduced enough at stations northeast of Subevent 3 such as KMM004, where the effect of rupture directivity was significant, while the amplitude was well reproduced at most of the other stations. This

  13. Regionally Adaptable Ground Motion Prediction Equation (GMPE) from Empirical Models of Fourier and Duration of Ground Motion

    NASA Astrophysics Data System (ADS)

    Bora, Sanjay; Scherbaum, Frank; Kuehn, Nicolas; Stafford, Peter; Edwards, Benjamin

    2016-04-01

    The current practice of deriving empirical ground motion prediction equations (GMPEs) involves using ground motions recorded at multiple sites. However, in applications like site-specific (e.g., critical facility) hazard ground motions obtained from the GMPEs are need to be adjusted/corrected to a particular site/site-condition under investigation. This study presents a complete framework for developing a response spectral GMPE, within which the issue of adjustment of ground motions is addressed in a manner consistent with the linear system framework. The present approach is a two-step process in which the first step consists of deriving two separate empirical models, one for Fourier amplitude spectra (FAS) and the other for a random vibration theory (RVT) optimized duration (Drvto) of ground motion. In the second step the two models are combined within the RVT framework to obtain full response spectral amplitudes. Additionally, the framework also involves a stochastic model based extrapolation of individual Fourier spectra to extend the useable frequency limit of the empirically derived FAS model. The stochastic model parameters were determined by inverting the Fourier spectral data using an approach similar to the one as described in Edwards and Faeh (2013). Comparison of median predicted response spectra from present approach with those from other regional GMPEs indicates that the present approach can also be used as a stand-alone model. The dataset used for the presented analysis is a subset of the recently compiled database RESORCE-2012 across Europe, the Middle East and the Mediterranean region.

  14. Joint PET-MR respiratory motion models for clinical PET motion correction

    NASA Astrophysics Data System (ADS)

    Manber, Richard; Thielemans, Kris; Hutton, Brian F.; Wan, Simon; McClelland, Jamie; Barnes, Anna; Arridge, Simon; Ourselin, Sébastien; Atkinson, David

    2016-09-01

    Patient motion due to respiration can lead to artefacts and blurring in positron emission tomography (PET) images, in addition to quantification errors. The integration of PET with magnetic resonance (MR) imaging in PET-MR scanners provides complementary clinical information, and allows the use of high spatial resolution and high contrast MR images to monitor and correct motion-corrupted PET data. In this paper we build on previous work to form a methodology for respiratory motion correction of PET data, and show it can improve PET image quality whilst having minimal impact on clinical PET-MR protocols. We introduce a joint PET-MR motion model, using only 1 min per PET bed position of simultaneously acquired PET and MR data to provide a respiratory motion correspondence model that captures inter-cycle and intra-cycle breathing variations. In the model setup, 2D multi-slice MR provides the dynamic imaging component, and PET data, via low spatial resolution framing and principal component analysis, provides the model surrogate. We evaluate different motion models (1D and 2D linear, and 1D and 2D polynomial) by computing model-fit and model-prediction errors on dynamic MR images on a data set of 45 patients. Finally we apply the motion model methodology to 5 clinical PET-MR oncology patient datasets. Qualitative PET reconstruction improvements and artefact reduction are assessed with visual analysis, and quantitative improvements are calculated using standardised uptake value (SUVpeak and SUVmax) changes in avid lesions. We demonstrate the capability of a joint PET-MR motion model to predict respiratory motion by showing significantly improved image quality of PET data acquired before the motion model data. The method can be used to incorporate motion into the reconstruction of any length of PET acquisition, with only 1 min of extra scan time, and with no external hardware required.

  15. Multiple LacI-mediated loops revealed by Bayesian statistics and tethered particle motion

    PubMed Central

    Johnson, Stephanie; van de Meent, Jan-Willem; Phillips, Rob; Wiggins, Chris H.; Lindén, Martin

    2014-01-01

    The bacterial transcription factor LacI loops DNA by binding to two separate locations on the DNA simultaneously. Despite being one of the best-studied model systems for transcriptional regulation, the number and conformations of loop structures accessible to LacI remain unclear, though the importance of multiple coexisting loops has been implicated in interactions between LacI and other cellular regulators of gene expression. To probe this issue, we have developed a new analysis method for tethered particle motion, a versatile and commonly used in vitro single-molecule technique. Our method, vbTPM, performs variational Bayesian inference in hidden Markov models. It learns the number of distinct states (i.e. DNA–protein conformations) directly from tethered particle motion data with better resolution than existing methods, while easily correcting for common experimental artifacts. Studying short (roughly 100 bp) LacI-mediated loops, we provide evidence for three distinct loop structures, more than previously reported in single-molecule studies. Moreover, our results confirm that changes in LacI conformation and DNA-binding topology both contribute to the repertoire of LacI-mediated loops formed in vitro, and provide qualitatively new input for models of looping and transcriptional regulation. We expect vbTPM to be broadly useful for probing complex protein–nucleic acid interactions. PMID:25120267

  16. A statistical shape and motion model for the prediction of respiratory lung motion

    NASA Astrophysics Data System (ADS)

    Ehrhardt, Jan; Werner, René; Schmidt-Richberg, Alexander; Handels, Heinz

    2010-03-01

    We propose a method to compute a 4D statistical model of respiratory lung motion which consists of a 3D shape atlas, a 4D mean motion model and a 4D motion variability model. Symmetric diffeomorphic image registration is used to estimate subject-specific motion models, to generate an average shape and intensity atlas of the lung as anatomical reference frame and to establish inter-subject correspondence. The Log-Euclidean framework allows to perform statistics on diffeomorphic transformations via vectorial statistics on their logarithms. We apply this framework to compute the mean motion and motion variations by performing a Principal Component Analysis (PCA) on diffeomorphisms. Furthermore, we present methods to adapt the generated statistical 4D motion model to a patient-specific lung geometry and the individual organ motion. The prediction performance is evaluated with respect to motion field differences and with respect to landmark- based target registration errors. The quantitative analysis results in a mean target registration error of 3,2 +/- 1,8 mm. The results show that the new method is able to provide valuable knowledge in many fields of application.

  17. One hybrid model combining singular spectrum analysis and LS + ARMA for polar motion prediction

    NASA Astrophysics Data System (ADS)

    Shen, Yi; Guo, Jinyun; Liu, Xin; Wei, Xiaobei; Li, Wudong

    2017-01-01

    Accurate real-time polar motion parameters play an important role in satellite navigation and positioning and spacecraft tracking. To meet the needs for real-time and high-accuracy polar motion prediction, a hybrid model that integrated singular spectrum analysis (SSA), least-squares (LS) extrapolation and an autoregressive moving average (ARMA) model was proposed. SSA was applied to separate the trend, the annual and the Chandler components from a given polar motion time series. LS extrapolation models were constructed for the separated trend, annual and Chandler components. An ARMA model was established for a synthetic sequence that contained the remaining SSA component and the residual series of LS fitting. In applying this hybrid model, multiple sets of polar motion predictions with lead times of 360 days were made based on an IERS 08 C04 series. The results showed that the proposed method could effectively predict the polar motion parameters.

  18. An Inexpensive Mechanical Model for Projectile Motion

    ERIC Educational Resources Information Center

    Kagan, David

    2011-01-01

    As experienced physicists, we see the beauty and simplicity of projectile motion. It is merely the superposition of uniform linear motion along the direction of the initial velocity vector and the downward motion due to the constant acceleration of gravity. We see the kinematic equations as just the mathematical machinery to perform the…

  19. An Inexpensive Mechanical Model for Projectile Motion

    ERIC Educational Resources Information Center

    Kagan, David

    2011-01-01

    As experienced physicists, we see the beauty and simplicity of projectile motion. It is merely the superposition of uniform linear motion along the direction of the initial velocity vector and the downward motion due to the constant acceleration of gravity. We see the kinematic equations as just the mathematical machinery to perform the…

  20. Models of subjective response to in-flight motion data

    NASA Technical Reports Server (NTRS)

    Rudrapatna, A. N.; Jacobson, I. D.

    1973-01-01

    Mathematical relationships between subjective comfort and environmental variables in an air transportation system are investigated. As a first step in model building, only the motion variables are incorporated and sensitivities are obtained using stepwise multiple regression analysis. The data for these models have been collected from commercial passenger flights. Two models are considered. In the first, subjective comfort is assumed to depend on rms values of the six-degrees-of-freedom accelerations. The second assumes a Rustenburg type human response function in obtaining frequency weighted rms accelerations, which are used in a linear model. The form of the human response function is examined and the results yield a human response weighting function for different degrees of freedom.

  1. A hybrid deconvolution approach to separate acoustic sources in multiple motion modes.

    PubMed

    Mo, Pinxi; Jiang, Weikang

    2017-07-01

    Motion mode is defined as a characteristic motion that a group of sources follow. If there are multiple groups of sources moving in the corresponding multiple motion modes, the beamforming map for a certain group of sources will be contaminated by the leakages from the other groups of sources. The original beamforming or deconvolution approaches fail to interpret the acoustic maps, as the source leakages may be mistaken for actual sources. A hybrid deconvolution approach is proposed to restrain the source leakages, so as to separate the acoustic sources in multiple motion modes. This approach simultaneously considers all the sources in the potential motion modes, and introduces equivalent sources in the corresponding motion modes to represent the sources. The equivalence between the actual sources and the equivalent sources leads to the construction of an expanded linear matrix equation. The sources in the respective motion modes are simultaneously extracted by solving the equation. The approach is shown effective by two numerical simulations and a practical experiment on two counter-rotating sources and one static source.

  2. Modeling depth from motion parallax with the motion/pursuit ratio.

    PubMed

    Nawrot, Mark; Ratzlaff, Michael; Leonard, Zachary; Stroyan, Keith

    2014-01-01

    The perception of unambiguous scaled depth from motion parallax relies on both retinal image motion and an extra-retinal pursuit eye movement signal. The motion/pursuit ratio represents a dynamic geometric model linking these two proximal cues to the ratio of depth to viewing distance. An important step in understanding the visual mechanisms serving the perception of depth from motion parallax is to determine the relationship between these stimulus parameters and empirically determined perceived depth magnitude. Observers compared perceived depth magnitude of dynamic motion parallax stimuli to static binocular disparity comparison stimuli at three different viewing distances, in both head-moving and head-stationary conditions. A stereo-viewing system provided ocular separation for stereo stimuli and monocular viewing of parallax stimuli. For each motion parallax stimulus, a point of subjective equality (PSE) was estimated for the amount of binocular disparity that generates the equivalent magnitude of perceived depth from motion parallax. Similar to previous results, perceived depth from motion parallax had significant foreshortening. Head-moving conditions produced even greater foreshortening due to the differences in the compensatory eye movement signal. An empirical version of the motion/pursuit law, termed the empirical motion/pursuit ratio, which models perceived depth magnitude from these stimulus parameters, is proposed.

  3. Modeling depth from motion parallax with the motion/pursuit ratio

    PubMed Central

    Nawrot, Mark; Ratzlaff, Michael; Leonard, Zachary; Stroyan, Keith

    2014-01-01

    The perception of unambiguous scaled depth from motion parallax relies on both retinal image motion and an extra-retinal pursuit eye movement signal. The motion/pursuit ratio represents a dynamic geometric model linking these two proximal cues to the ratio of depth to viewing distance. An important step in understanding the visual mechanisms serving the perception of depth from motion parallax is to determine the relationship between these stimulus parameters and empirically determined perceived depth magnitude. Observers compared perceived depth magnitude of dynamic motion parallax stimuli to static binocular disparity comparison stimuli at three different viewing distances, in both head-moving and head-stationary conditions. A stereo-viewing system provided ocular separation for stereo stimuli and monocular viewing of parallax stimuli. For each motion parallax stimulus, a point of subjective equality (PSE) was estimated for the amount of binocular disparity that generates the equivalent magnitude of perceived depth from motion parallax. Similar to previous results, perceived depth from motion parallax had significant foreshortening. Head-moving conditions produced even greater foreshortening due to the differences in the compensatory eye movement signal. An empirical version of the motion/pursuit law, termed the empirical motion/pursuit ratio, which models perceived depth magnitude from these stimulus parameters, is proposed. PMID:25339926

  4. Modeling Human Control of Self-Motion Direction With Optic Flow and Vestibular Motion.

    PubMed

    Zaal, Peter M T; Nieuwenhuizen, Frank M; van Paassen, Marinus M; Mulder, Max

    2013-04-01

    In this paper, we investigate the effects of visual and motion stimuli on the manual control of one's direction of self-motion. In a flight simulator, subjects conducted an active target-following disturbance-rejection task, using a compensatory display. Simulating a vehicular control task, the direction of vehicular motion was shown on the outside visual display in two ways: an explicit presentation using a symbol and an implicit presentation, namely, through the focus of radial outflow that emerges from optic flow. In addition, the effects of the relative strength of congruent vestibular motion cues were investigated. The dynamic properties of human visual and vestibular motion perception paths were modeled using a control-theoretical approach. As expected, improved tracking performance was found for the configurations that explicitly showed the direction of self-motion. The human visual time delay increased with approximately 150 ms for the optic flow conditions, relative to explicit presentations. Vestibular motion, providing higher order information on the direction of self-motion, allowed subjects to partially compensate for this visual perception delay, improving performance. Parameter estimates of the operator control model show that, with vestibular motion, the visual feedback becomes stronger, indicating that operators are more confident to act on optic flow information when congruent vestibular motion cues are present.

  5. Atomic Models for Motional Stark Effects Diagnostics

    SciTech Connect

    Gu, M F; Holcomb, C; Jayakuma, J; Allen, S; Pablant, N A; Burrell, K

    2007-07-26

    We present detailed atomic physics models for motional Stark effects (MSE) diagnostic on magnetic fusion devices. Excitation and ionization cross sections of the hydrogen or deuterium beam traveling in a magnetic field in collisions with electrons, ions, and neutral gas are calculated in the first Born approximation. The density matrices and polarization states of individual Stark-Zeeman components of the Balmer {alpha} line are obtained for both beam into plasma and beam into gas models. A detailed comparison of the model calculations and the MSE polarimetry and spectral intensity measurements obtained at the DIII-D tokamak is carried out. Although our beam into gas models provide a qualitative explanation for the larger {pi}/{sigma} intensity ratios and represent significant improvements over the statistical population models, empirical adjustment factors ranging from 1.0-2.0 must still be applied to individual line intensities to bring the calculations into full agreement with the observations. Nevertheless, we demonstrate that beam into gas measurements can be used successfully as calibration procedures for measuring the magnetic pitch angle through {pi}/{sigma} intensity ratios. The analyses of the filter-scan polarization spectra from the DIII-D MSE polarimetry system indicate unknown channel and time dependent light contaminations in the beam into gas measurements. Such contaminations may be the main reason for the failure of beam into gas calibration on MSE polarimetry systems.

  6. Anisotropic multiple bounce models

    NASA Astrophysics Data System (ADS)

    Bacalhau, Anna Paula; Peter, Patrick; Vitenti, Sandro D. P.

    2017-07-01

    We analyze the Galileon ghost condensate implementation of a bouncing cosmological model in the presence of a non-negligible anisotropic stress. We exhibit its structure, which we find to be far richer than previously thought. In particular, even restricting attention to a single set of underlying microscopic parameters, we obtain, numerically, many qualitatively different regimes: depending on the initial conditions on the scalar field leading the dynamics of the Universe, the contraction phase can evolve directly towards a singularity, avoid it by bouncing once, or even bounce many times before settling into an ever-expanding phase. We clarify the behavior of the anisotropies in these various situations.

  7. Modeling and incorporating cardiac-induced lung tissue motion in a breathing motion model

    PubMed Central

    White, Benjamin M.; Santhanam, Anand; Thomas, David; Min, Yugang; Lamb, James M.; Neylon, Jack; Jani, Shyam; Gaudio, Sergio; Srinivasan, Subashini; Ennis, Daniel; Low, Daniel A.

    2014-01-01

    Purpose: The purpose of this work is to develop a cardiac-induced lung motion model to be integrated into an existing breathing motion model. Methods: The authors’ proposed cardiac-induced lung motion model represents the lung tissue's specific response to the subject's cardiac cycle. The model is mathematically defined as a product of a converging polynomial function h of the cardiac phase (c) and the maximum displacement \\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{upgreek} \\usepackage{mathrsfs} \\setlength{\\oddsidemargin}{-69pt} \\begin{document} \\smash{\\mathord{\\buildrel{\\lower3pt\\hbox{\\scriptscriptstyle\\rightharpoonup}}\\over \\gamma } ( {\\mathord{\\buildrel{\\lower3pt\\hbox{\\scriptscriptstyle\\rightharpoonup}}\\over X} _0 } )}\\end{document}γ⇀(X⇀0) of each voxel (\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{upgreek} \\usepackage{mathrsfs} \\setlength{\\oddsidemargin}{-69pt} \\begin{document} \\smash{\\mathord{\\buildrel{\\lower3pt\\hbox{\\scriptscriptstyle\\rightharpoonup}}\\over X} _0 }\\end{document}X⇀0) among all the cardiac phases. The function h(c) was estimated from cardiac-gated MR imaging of ten healthy volunteers using an Akaike Information Criteria optimization algorithm. For each volunteer, a total of 24 short-axis and 18 radial planar views were acquired on a 1.5 T MR scanner during a series of 12–15 s breath-hold maneuvers. Each view contained 30 temporal frames of equal time-duration beginning with the end-diastolic cardiac phase. The frames in each of the planar views were resampled to create a set of three-dimensional (3D) anatomical volumes representing thoracic anatomy at different cardiac phases. A 3D multiresolution optical flow deformable image registration algorithm was used to quantify the difference

  8. Characterization of myocardial motion patterns by unsupervised multiple kernel learning.

    PubMed

    Sanchez-Martinez, Sergio; Duchateau, Nicolas; Erdei, Tamas; Fraser, Alan G; Bijnens, Bart H; Piella, Gemma

    2017-01-01

    We propose an independent objective method to characterize different patterns of functional responses to stress in the heart failure with preserved ejection fraction (HFPEF) syndrome by combining multiple temporally-aligned myocardial velocity traces at rest and during exercise, together with temporal information on the occurrence of cardiac events (valves openings/closures and atrial activation). The method builds upon multiple kernel learning, a machine learning technique that allows the combination of data of different nature and the reduction of their dimensionality towards a meaningful representation (output space). The learning process is kept unsupervised, to study the variability of the input traces without being conditioned by data labels. To enhance the physiological interpretation of the output space, the variability that it encodes is analyzed in the space of input signals after reconstructing the velocity traces via multiscale kernel regression. The methodology was applied to 2D sequences from a stress echocardiography protocol from 55 subjects (22 healthy, 19 HFPEF and 14 breathless subjects). The results confirm that characterization of the myocardial functional response to stress in the HFPEF syndrome may be improved by the joint analysis of multiple relevant features.

  9. Head Motion Modeling for Human Behavior Analysis in Dyadic Interaction

    PubMed Central

    Xiao, Bo; Georgiou, Panayiotis; Baucom, Brian; Narayanan, Shrikanth S.

    2015-01-01

    This paper presents a computational study of head motion in human interaction, notably of its role in conveying interlocutors’ behavioral characteristics. Head motion is physically complex and carries rich information; current modeling approaches based on visual signals, however, are still limited in their ability to adequately capture these important properties. Guided by the methodology of kinesics, we propose a data driven approach to identify typical head motion patterns. The approach follows the steps of first segmenting motion events, then parametrically representing the motion by linear predictive features, and finally generalizing the motion types using Gaussian mixture models. The proposed approach is experimentally validated using video recordings of communication sessions from real couples involved in a couples therapy study. In particular we use the head motion model to classify binarized expert judgments of the interactants’ specific behavioral characteristics where entrainment in head motion is hypothesized to play a role: Acceptance, Blame, Positive, and Negative behavior. We achieve accuracies in the range of 60% to 70% for the various experimental settings and conditions. In addition, we describe a measure of motion similarity between the interaction partners based on the proposed model. We show that the relative change of head motion similarity during the interaction significantly correlates with the expert judgments of the interactants’ behavioral characteristics. These findings demonstrate the effectiveness of the proposed head motion model, and underscore the promise of analyzing human behavioral characteristics through signal processing methods. PMID:26557047

  10. Vestibular models for design and evaluation of flight simulator motion

    NASA Technical Reports Server (NTRS)

    Bussolari, S. R.; Sullivan, R. B.; Young, L. R.

    1986-01-01

    The use of spatial orientation models in the design and evaluation of control systems for motion-base flight simulators is investigated experimentally. The development of a high-fidelity motion drive controller using an optimal control approach based on human vestibular models is described. The formulation and implementation of the optimal washout system are discussed. The effectiveness of the motion washout system was evaluated by studying the response of six motion washout systems to the NASA/AMES Vertical Motion Simulator for a single dash-quick-stop maneuver. The effects of the motion washout system on pilot performance and simulator acceptability are examined. The data reveal that human spatial orientation models are useful for the design and evaluation of flight simulator motion fidelity.

  11. High-capacity, transient retention of direction-of-motion information for multiple moving objects

    PubMed Central

    Shooner, Christopher; Tripathy, Srimant P.; Bedell, Harold E.; Öğmen, Haluk

    2011-01-01

    The multiple-object tracking paradigm (MOT) has been used extensively for studying dynamic visual attention, but the basic mechanisms which subserve this capability are as yet unknown. Among the unresolved issues surrounding MOT are the relative importance of motion (as opposed to positional) information and the role of various memory mechanisms. We sought to quantify the capacity and dynamics for retention of direction-of-motion information when viewing a multiple-object motion stimulus similar to those used in MOT. Observers viewed three to nine objects in random linear motion and then reported motion direction after motion ended. Using a partial-report paradigm and varying the parameters of set size and time of retention, we found evidence for two complementary memory systems, one transient with high capacity and a second sustained system with low capacity. For the transient high-capacity memory, retention capacity was equally high whether object motion lasted several seconds or a fraction of a second. Also, a graded deterioration in performance with increased set size lends support to a flexible-capacity theory of MOT. PMID:20884557

  12. High-capacity, transient retention of direction-of-motion information for multiple moving objects.

    PubMed

    Shooner, Christopher; Tripathy, Srimant P; Bedell, Harold E; Ogmen, Haluk

    2010-06-01

    The multiple-object tracking paradigm (MOT) has been used extensively for studying dynamic visual attention, but the basic mechanisms which subserve this capability are as yet unknown. Among the unresolved issues surrounding MOT are the relative importance of motion (as opposed to positional) information and the role of various memory mechanisms. We sought to quantify the capacity and dynamics for retention of direction-of-motion information when viewing a multiple-object motion stimulus similar to those used in MOT. Observers viewed three to nine objects in random linear motion and then reported motion direction after motion ended. Using a partial-report paradigm and varying the parameters of set size and time of retention, we found evidence for two complementary memory systems, one transient with high capacity and a second sustained system with low capacity. For the transient high-capacity memory, retention capacity was equally high whether object motion lasted several seconds or a fraction of a second. Also, a graded deterioration in performance with increased set size lends support to a flexible-capacity theory of MOT.

  13. Coriolis effects and motion sickness modelling.

    PubMed

    Bles, W

    1998-11-15

    Coriolis effects are notorious in relation to disorientation and motion sickness in aircrew. A review is provided of experimental data on these Coriolis effects, including the modulatory effects of adding visual or somatosensory rotatory motion information. A vector analysis of the consequences of head movements during somatosensory, visual and/or vestibular rotatory motion stimulation revealed that the more the sensed angular velocity vector after the head movements is aligned with the gravitoinertial force vector, the less nauseating effects are experienced. It is demonstrated that this is a special case of the subjective vertical conflict theory on motion sickness that assumes that motion sickness may be provoked if a discrepancy is detected between the subjective vertical and the sensed vertical as determined on the basis of incoming sensory information.

  14. A Model of Binocular Motion Integration in MT Neurons.

    PubMed

    Baker, Pamela M; Bair, Wyeth

    2016-06-15

    Primate cortical area MT plays a central role in visual motion perception, but models of this area have largely overlooked the binocular integration of motion signals. Recent electrophysiological studies tested binocular integration in MT and found surprisingly that MT neurons lose their hallmark "pattern motion" selectivity when stimuli are presented dichoptically and that many neurons are selective for motion-in-depth (MID). By unifying these novel observations with insights from monocular, frontoparallel motion studies concurrently in a binocular MT motion model, we generated clear, testable predictions about the circuitry and mechanisms underlying visual motion processing. We built binocular models in which signals from left- and right-eye streams could be integrated at various stages from V1 to MT, attempting to create the simplest plausible circuits that accounted for the physiological range of pattern motion selectivity, that explained changes across this range for dichoptic stimulus presentation, and that spanned the spectrum of MID selectivity observed in MT. Our successful models predict that motion-opponent suppression is the key mechanism to account for the striking loss of pattern motion sensitivity with dichoptic plaids, that opponent suppression precedes binocular integration, and that opponent suppression will be stronger in inputs to pattern cells than to component cells. We also found an unexpected connection between circuits for pattern motion selectivity and MID selectivity, suggesting that these two separately studied phenomena could be related. These results also hold in models that include binocular disparity computations, providing a platform for future exploration of binocular response properties in MT. The neural pathways underlying our sense of visual motion are among the most studied and well-understood parts of the primate cerebral cortex. Nevertheless, our understanding is incomplete because electrophysiological research has focused

  15. Lung respiration motion modeling: a sparse motion field presentation method using biplane x-ray images

    NASA Astrophysics Data System (ADS)

    Chen, Dong; Xie, Hongzhi; Zhang, Shuyang; Gu, Lixu

    2017-10-01

    Respiration-introduced tumor location uncertainty is a challenge in the precise lung biopsy for lung lesions. Current statistical modeling approaches hardly capture the complex local respiratory motion information. In this study, we formulate a statistical respiratory motion model using biplane x-ray images to improve the accuracy of motion field estimation by efficiently preserving local motion details for specific patients. Given CT data sets of 18 healthy subjects at end-expiratory and end-inspiratory breathing phases, the respiratory motion field is constructed based on deformation vector fields which are extracted from these CT data sets, and a lung contour motion repository respiratory is generated dependent on displacements of boundary control points. By varying the sparse weight coefficients of the statistical sparse motion field presentation (SMFP) method, the newly-input motion field is approximately presented by a sparse linear combination of a subset of the motion repository. The SMFP method is employed twice in the coefficient optimization process. Finally, these non-zero coefficients are fine-tuned to maximize the similarity between the projection image of reconstructed volumetric images and the current x-ray image. We performed the proposed method for estimating respiratory motion field on ten subject datasets and compared the result with the PCA method. The maximum average target registration error of the PCA-based and the SMFP-based respiratory motion field estimation are 3.1(2.0) and 2.9(1.6) mm, respectively. The maximum average symmetric surface distance of two methods are 2.5(1.6) and 2.4(1.3) mm, respectively.

  16. Modeling of ship maneuvering motion using neural networks

    NASA Astrophysics Data System (ADS)

    Luo, Weilin; Zhang, Zhicheng

    2016-12-01

    In this paper, Neural Networks (NNs) are used in the modeling of ship maneuvering motion. A nonlinear response model and a linear hydrodynamic model of ship maneuvering motion are also investigated. The maneuverability indices and linear non-dimensional hydrodynamic derivatives in the models are identified by using two-layer feed forward NNs. The stability of parametric estimation is confirmed. Then, the ship maneuvering motion is predicted based on the obtained models. A comparison between the predicted results and the model test results demonstrates the validity of the proposed modeling method.

  17. Monitoring gait in multiple sclerosis with novel wearable motion sensors.

    PubMed

    Moon, Yaejin; McGinnis, Ryan S; Seagers, Kirsten; Motl, Robert W; Sheth, Nirav; Wright, John A; Ghaffari, Roozbeh; Sosnoff, Jacob J

    2017-01-01

    Mobility impairment is common in people with multiple sclerosis (PwMS) and there is a need to assess mobility in remote settings. Here, we apply a novel wireless, skin-mounted, and conformal inertial sensor (BioStampRC, MC10 Inc.) to examine gait characteristics of PwMS under controlled conditions. We determine the accuracy and precision of BioStampRC in measuring gait kinematics by comparing to contemporary research-grade measurement devices. A total of 45 PwMS, who presented with diverse walking impairment (Mild MS = 15, Moderate MS = 15, Severe MS = 15), and 15 healthy control subjects participated in the study. Participants completed a series of clinical walking tests. During the tests participants were instrumented with BioStampRC and MTx (Xsens, Inc.) sensors on their shanks, as well as an activity monitor GT3X (Actigraph, Inc.) on their non-dominant hip. Shank angular velocity was simultaneously measured with the inertial sensors. Step number and temporal gait parameters were calculated from the data recorded by each sensor. Visual inspection and the MTx served as the reference standards for computing the step number and temporal parameters, respectively. Accuracy (error) and precision (variance of error) was assessed based on absolute and relative metrics. Temporal parameters were compared across groups using ANOVA. Mean accuracy±precision for the BioStampRC was 2±2 steps error for step number, 6±9ms error for stride time and 6±7ms error for step time (0.6-2.6% relative error). Swing time had the least accuracy±precision (25±19ms error, 5±4% relative error) among the parameters. GT3X had the least accuracy±precision (8±14% relative error) in step number estimate among the devices. Both MTx and BioStampRC detected significantly distinct gait characteristics between PwMS with different disability levels (p<0.01). BioStampRC sensors accurately and precisely measure gait parameters in PwMS across diverse walking impairment levels and detected

  18. Monitoring gait in multiple sclerosis with novel wearable motion sensors

    PubMed Central

    McGinnis, Ryan S.; Seagers, Kirsten; Motl, Robert W.; Sheth, Nirav; Wright, John A.; Ghaffari, Roozbeh; Sosnoff, Jacob J.

    2017-01-01

    Background Mobility impairment is common in people with multiple sclerosis (PwMS) and there is a need to assess mobility in remote settings. Here, we apply a novel wireless, skin-mounted, and conformal inertial sensor (BioStampRC, MC10 Inc.) to examine gait characteristics of PwMS under controlled conditions. We determine the accuracy and precision of BioStampRC in measuring gait kinematics by comparing to contemporary research-grade measurement devices. Methods A total of 45 PwMS, who presented with diverse walking impairment (Mild MS = 15, Moderate MS = 15, Severe MS = 15), and 15 healthy control subjects participated in the study. Participants completed a series of clinical walking tests. During the tests participants were instrumented with BioStampRC and MTx (Xsens, Inc.) sensors on their shanks, as well as an activity monitor GT3X (Actigraph, Inc.) on their non-dominant hip. Shank angular velocity was simultaneously measured with the inertial sensors. Step number and temporal gait parameters were calculated from the data recorded by each sensor. Visual inspection and the MTx served as the reference standards for computing the step number and temporal parameters, respectively. Accuracy (error) and precision (variance of error) was assessed based on absolute and relative metrics. Temporal parameters were compared across groups using ANOVA. Results Mean accuracy±precision for the BioStampRC was 2±2 steps error for step number, 6±9ms error for stride time and 6±7ms error for step time (0.6–2.6% relative error). Swing time had the least accuracy±precision (25±19ms error, 5±4% relative error) among the parameters. GT3X had the least accuracy±precision (8±14% relative error) in step number estimate among the devices. Both MTx and BioStampRC detected significantly distinct gait characteristics between PwMS with different disability levels (p<0.01). Conclusion BioStampRC sensors accurately and precisely measure gait parameters in PwMS across diverse walking

  19. A Multi-rhythmic Oscillator Model that Can Integrate Motion Stabilization with Motion Exploration

    NASA Astrophysics Data System (ADS)

    Owaki, Dai; Sakai, Yoshiyuki; Ishida, Satoshi; Tero, Atsushi; Ishiguro, Akio

    Central pattern generators (CPGs) have been increasingly attracting roboticists in the hope that they enable robots to realize truly supple and agile locomotion under real world constraints. Thus far, various CPG models have been proposed, particularly in terms of motion stabilization against external perturbations, i.e., limit cycle behavior. On the other hand, biological CPGs have another crucial aspect that cannot be neglected, i.e., motion exploration. Here, note that motion stabilization and motion exploration should be performed in different time-scales. Now the following questions arise: how can different time-scales be embedded into a single CPG effectively?; and what is a good mathematical tool for describing the coexistence of different time-scales? To overcome these problems, this paper introduces a novel oscillator model in which the two functions of motion stabilization and motion exploration can be seamlessly integrated by exploiting the concept of multi-rhythmicity, without relying on any hierarchical structure, which in turn enables that learning is an integral part of the motor control system. We applied this model to the learning of hopping motion as a practical example. Simulation results indicate that the robot can successfully perform online learning without the need for a separation between learning and performance phases.

  20. An Inexpensive Mechanical Model for Projectile Motion

    NASA Astrophysics Data System (ADS)

    Kagan, David

    2011-05-01

    As experienced physicists, we see the beauty and simplicity of projectile motion. It is merely the superposition of uniform linear motion along the direction of the initial velocity vector and the downward motion due to the constant acceleration of gravity. We see the kinematic equations as just the mathematical machinery to perform the calculations. What do our students see? Likely, most see no deeper than the operational understanding needed to use the kinematic equations. Described below is a device (shown in Fig. 1) that illustrates the physicist's view of projectile motion. It can be used as a classroom demonstration or as a project for your students, and it costs less than three dollars to make.

  1. Inter-fraction variations in respiratory motion models

    NASA Astrophysics Data System (ADS)

    McClelland, J. R.; Hughes, S.; Modat, M.; Qureshi, A.; Ahmad, S.; Landau, D. B.; Ourselin, S.; Hawkes, D. J.

    2011-01-01

    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.

  2. Inter-fraction variations in respiratory motion models.

    PubMed

    McClelland, J R; Hughes, S; Modat, M; Qureshi, A; Ahmad, S; Landau, D B; Ourselin, S; Hawkes, D J

    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.

  3. Detecting and Analyzing Multiple Moving Objects in Crowded Environments with Coherent Motion Regions

    SciTech Connect

    Cheriyadat, Anil M.

    2013-01-04

    Understanding the world around us from large-scale video data requires vision systems that can perform automatic interpretation. While human eyes can unconsciously perceive independent objects in crowded scenes and other challenging operating environments, automated systems have difficulty detecting, counting, and understanding their behavior in similar scenes. Computer scientists at ORNL have a developed a technology termed as "Coherent Motion Region Detection" that invloves identifying multiple indepedent moving objects in crowded scenes by aggregating low-level motion cues extracted from moving objects. Humans and other species exploit such low-level motion cues seamlessely to perform perceptual grouping for visual understanding. The algorithm detects and tracks feature points on moving objects resulting in partial trajectories that span coherent 3D region in the space-time volume defined by the video. In the case of multi-object motion, many possible coherent motion regions can be constructed around the set of trajectories. The unique approach in the algorithm is to identify all possible coherent motion regions, then extract a subset of motion regions based on an innovative measure to automatically locate moving objects in crowded environments.The software reports snapshot of the object, count, and derived statistics ( count over time) from input video streams. The software can directly process videos streamed over the internet or directly from a hardware device (camera).

  4. MOTION SENSORS IN MULTIPLE SCLEROSIS: NARRATIVE REVIEW AND UPDATE OF APPLICATIONS.

    PubMed

    Sasaki, Jeffer Eidi; Sandroff, Brian; Bamman, Marcas; Motl, Robert W

    2017-09-28

    The use of motion sensors for measuring physical activity in multiple sclerosis (MS) has evolved with increasing research particularly during the past decade. Areas covered: This manuscript reviews the literature regarding the application of motion sensors for measuring physical activity in MS. We first describe 'what is known' about their use in MS by examining the evidence generated between 1997 and 2012, including the psychometric properties of motion sensors in MS and the development of MS-specific accelerometer cut-points. We then evaluate 'what is new' based on research conducted between 2013 and 2017. This includes newer research on psychometric properties of motion sensors in MS, development of new MS-specific accelerometer and step-rate cut-points, sedentary behavior assessment, and research on fitness trackers and multisensors in MS. The final part presents a picture of "what is next" for the applications of motion sensors in MS, especially pertaining new opportunities for testing and using fitness trackers in MS, and tracking disease and disability progression based on motion sensor output. Expert commentary: The use of motion sensors in MS has grown substantially over the years; however, a lot more can be done to explore the full potential and utility of these devices in MS.

  5. Image-guided tumor motion modeling and tracking

    NASA Astrophysics Data System (ADS)

    Zhang, J.; Wu, Y.; Liu, W.; Christensen, J.; Tai, A.; Li, A. X.

    2009-02-01

    Radiation therapy (RT) is an important procedure in the treatment of cancer in the thorax and abdomen. However, its efficacy can be severely limited by breathing induced tumor motion. Tumor motion causes uncertainty in the tumor's location and consequently limits the radiation dosage (for fear of damaging normal tissue). This paper describes a novel signal model for tumor motion tracking/prediction that can potentially improve RT results. Using CT and breathing sensor data, it provides a more accurate characterization of the breathing and tumor motion than previous work and is non-invasive. The efficacy of our model is demonstrated on patient data.

  6. Moving from spatially segregated to transparent motion: a modelling approach

    PubMed Central

    Durant, Szonya; Donoso-Barrera, Alejandra; Tan, Sovira; Johnston, Alan

    2005-01-01

    Motion transparency, in which patterns of moving elements group together to give the impression of lacy overlapping surfaces, provides an important challenge to models of motion perception. It has been suggested that we perceive transparent motion when the shape of the velocity histogram of the stimulus is bimodal. To investigate this further, random-dot kinematogram motion sequences were created to simulate segregated (perceptually spatially separated) and transparent (perceptually overlapping) motion. The motion sequences were analysed using the multi-channel gradient model (McGM) to obtain the speed and direction at every pixel of each frame of the motion sequences. The velocity histograms obtained were found to be quantitatively similar and all were bimodal. However, the spatial and temporal properties of the velocity field differed between segregated and transparent stimuli. Transparent stimuli produced patches of rightward and leftward motion that varied in location over time. This demonstrates that we can successfully differentiate between these two types of motion on the basis of the time varying local velocity field. However, the percept of motion transparency cannot be based simply on the presence of a bimodal velocity histogram. PMID:17148338

  7. A neural model for the integration of stereopsis and motion parallax in structure-from-motion

    PubMed Central

    Fernandez, Julian Martin; Farell, Bart

    2008-01-01

    We introduce a model for the computation of structure-from-motion based on the physiology of visual cortical areas MT and MST. The model assumes that the perception of depth from motion is related to the firing of a subset of MT neurons tuned to both velocity and disparity. The model’s MT neurons are connected to each other laterally to form modulatory receptive-field surrounds that are gated by feedback connections from area MST. This allows the building up of a depth map from motion in area MT, even in absence of disparity in the input. Depth maps from motion and from stereo are combined by a weighted average at a final stage. The model’s predictions for the interaction between motion and stereo cues agree with previous psychophysical data, both when the cues are consistent with each other or when they are contradictory. In particular, the model shows nonlinearities as a result of early interactions between motion and stereo before their depth maps are averaged. The two cues interact in a way that represents an alternative to the “modified weak fusion” model of depth-cue combination. PMID:19255615

  8. Building Mathematical Models of Simple Harmonic and Damped Motion.

    ERIC Educational Resources Information Center

    Edwards, Thomas

    1995-01-01

    By developing a sequence of mathematical models of harmonic motion, shows that mathematical models are not right or wrong, but instead are better or poorer representations of the problem situation. (MKR)

  9. A test of alternative Caribbean plate relative motion models

    NASA Technical Reports Server (NTRS)

    Stein, Seth; Demets, Charles; Gordon, Richard G.; Brodholt, John; Argus, Don

    1988-01-01

    The new NUVEL-1 data set for global relative plate motions is used here to discriminate between the two prevailing models for Caribbean plate motion. One model, by Jordan (1975), assumes that North America-Caribbean motion is reflected by the spreading rate inferred from magnetic anomalies at the Cayman Spreading Center and the azimuths of nearby transforms. The other model, by Sykes et al. (1982), uses rates and azimuths inferred from the geometry of the Lesser Antilles Wadati-Benioff zone. Overall, it is found that the data fit the Jordan geometry better, that the data used in global plate motion models are more suitable than rates and azimuths inferred from the geometry of the Wadati-Benioff zone for determining relative motions, and that incorporation of all relevant plate boundaries is essential.

  10. Graphical Models as Surrogates for Complex Ground Motion Models

    NASA Astrophysics Data System (ADS)

    Vogel, K.; Riggelsen, C.; Kuehn, N.; Scherbaum, F.

    2012-04-01

    An essential part of the probabilistic seismic hazard analysis (PSHA) is the ground motion model, which estimates the conditional probability of a ground motion parameter, such as (horizontal) peak ground acceleration or spectral acceleration, given earthquake and site related predictor variables. For a reliable seismic hazard estimation the ground motion model has to keep the epistemic uncertainty small, while the aleatory uncertainty of the ground motion is covered by the model. In regions of well recorded seismicity the most popular modeling approach is to fit a regression function to the observed data, where the functional form is determined by expert knowledge. In regions, where we lack a sufficient amount of data, it is popular to fit the regression function to a data set generated by a so-called stochastic model, which distorts the shape of a random time series according to physical principles to obtain a time series with properties that match ground-motion characteristics. The stochastic model does not have nice analytical properties nor does it come in a form amenable for easy analytical handling and evaluation as needed for PSHA. Therefore a surrogate model, which describes the stochastic model in a more abstract sense (e.g. regression) is often used instead. We show how Directed Graphical Models (DGM) may be seen as a viable alternative to the classical regression approach. They describe a joint probability distribution of a set of variables, decomposing it into a product of (local) conditional probability distributions according to a directed acyclic graph. Graphical models have proven to be a all-round pre/descriptive probabilistic framework for many problems. Their transparent nature is attractive from a domain perspective allowing for a better understanding and gives direct insight into the relationships and workings of a system. DGMs learn the dependency structure of the parameters from the data and do not need, but can include prior expert

  11. Synchronous precessional motion of multiple domain walls in a ferromagnetic nanowire by perpendicular field pulses.

    PubMed

    Kim, June-Seo; Mawass, Mohamad-Assaad; Bisig, André; Krüger, Benjamin; Reeve, Robert M; Schulz, Tomek; Büttner, Felix; Yoon, Jungbum; You, Chun-Yeol; Weigand, Markus; Stoll, Hermann; Schütz, Gisela; Swagten, Henk J M; Koopmans, Bert; Eisebitt, Stefan; Kläui, Mathias

    2014-03-24

    Magnetic storage and logic devices based on magnetic domain wall motion rely on the precise and synchronous displacement of multiple domain walls. The conventional approach using magnetic fields does not allow for the synchronous motion of multiple domains. As an alternative method, synchronous current-induced domain wall motion was studied, but the required high-current densities prevent widespread use in devices. Here we demonstrate a radically different approach: we use out-of-plane magnetic field pulses to move in-plane domains, thus combining field-induced magnetization dynamics with the ability to move neighbouring domain walls in the same direction. Micromagnetic simulations suggest that synchronous permanent displacement of multiple magnetic walls can be achieved by using transverse domain walls with identical chirality combined with regular pinning sites and an asymmetric pulse. By performing scanning transmission X-ray microscopy, we are able to experimentally demonstrate in-plane magnetized domain wall motion due to out-of-plane magnetic field pulses.

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

    NASA Technical Reports Server (NTRS)

    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.

  13. FlyCap: Markerless Motion Capture Using Multiple Autonomous Flying Cameras.

    PubMed

    Xu, Lan; Liu, Yebin; Cheng, Wei; Guo, Kaiwen; Zhou, Guyue; Dai, Qionghai; Fang, Lu

    2017-07-18

    Aiming at automatic, convenient and non-instrusive motion capture, this paper presents a new generation markerless motion capture technique, the FlyCap system, to capture surface motions of moving characters using multiple autonomous flying cameras (autonomous unmanned aerial vehicles(UAVs) each integrated with an RGBD video camera). During data capture, three cooperative flying cameras automatically track and follow the moving target who performs large-scale motions in a wide space. We propose a novel non-rigid surface registration method to track and fuse the depth of the three flying cameras for surface motion tracking of the moving target, and simultaneously calculate the pose of each flying camera. We leverage the using of visual-odometry information provided by the UAV platform, and formulate the surface tracking problem in a non-linear objective function that can be linearized and effectively minimized through a Gaussian-Newton method. Quantitative and qualitative experimental results demonstrate the plausible surface and motion reconstruction results.

  14. A Stick Motion Compensation System with a Dynamic Model

    NASA Astrophysics Data System (ADS)

    Suzuki, Yasuhiko; Matsubara, Atsushi; Kakino, Yoshiaki; Tsutsui, Kazuhiko

    This paper deals with a stick motion compensation system. Stick motion is trajectory error that happens just after a quadrant change in circular motion on NC machine tools. Recently cylindrical machining with an end mill is often executed instead of boring machining with a bore tool. That is why the accuracy with end mill machining is becoming important. Stick motion extremely damages the accuracy and the quality of the circular parts or free form surfaces on workpieces. In the conventional compensation system, tuning parameters for each combination of radius and feed rate is needed. This research proposes a new stick motion compensation system. The new system has a dynamic model that simulates the friction. The simulated friction consists of two components. One is spring resistance in proportion to a reverse distance from a quadrant change. The other is viscous damping friction in proportion to velocity. The system can compensate stick motions suitably for wide range conditions of radii and feed rate.

  15. (Non-)geodesic motion in chameleon Brans Dicke model

    NASA Astrophysics Data System (ADS)

    Saaidi, K.

    2013-06-01

    Based on Das and Banerjee (Phys. Rev D 78:043512, 2008), we assume there is a non-minimal coupling between scalar field and matter in the Brans-Dicke model. We analyzes the motion of different matter such as, massless scalar field, photon, massless perfect fluid (dust), massive perfect fluid and point particle matter in this study. We show that the motion of massless scalar field and photon can satisfy null geodesic motion only in high frequency limit. Also we find that the motion of the dust and massive perfect fluid is geodesic for L m =- P and it is non-geodesic for L m = ρ. Finally, we study the motion of point particle and show that the motion of this kind of matter is like massive perfect fluid.

  16. A simple model for strong ground motions and response spectra

    USGS Publications Warehouse

    Safak, Erdal; Mueller, Charles; Boatwright, John

    1988-01-01

    A simple model for the description of strong ground motions is introduced. The model shows that response spectra can be estimated by using only four parameters of the ground motion, the RMS acceleration, effective duration and two corner frequencies that characterize the effective frequency band of the motion. The model is windowed band-limited white noise, and is developed by studying the properties of two functions, cumulative squared acceleration in the time domain, and cumulative squared amplitude spectrum in the frequency domain. Applying the methods of random vibration theory, the model leads to a simple analytical expression for the response spectra. The accuracy of the model is checked by using the ground motion recordings from the aftershock sequences of two different earthquakes and simulated accelerograms. The results show that the model gives a satisfactory estimate of the response spectra.

  17. Adapting liver motion models using a navigator channel technique

    PubMed Central

    Nguyen, T-N.; Moseley, J. L.; Dawson, L. A.; Jaffray, D. A.; Brock, K. K.

    2009-01-01

    Deformable registration can improve the accuracy of tumor targeting; however for online applications, efficiency as well as accuracy is important. A navigator channel technique has been developed to combine a biomechanical model-based deformable registration algorithm with a population motion model and patient specific motion information to perform fast deformable registration for application in image-guided radiation therapy. A respiratory population-based liver motion model was generated from breath-hold CT data sets of ten patients using a finite element model as a framework. The population model provides a biomechanical reference template of the average liver motions, which were found to be (absolute mean±SD) 0.12±0.10, 0.84±0.13, and 1.24±0.18 cm in the left-right (LR), anterior-posterior (AP), and superior-inferior (SI) directions, respectively. The population motion model was then adapted to the specific liver motion of 13 patients based on their exhale and inhale CT images. The patient motion was calculated using a navigator channel (a narrow region of interest window) on liver boundaries in the images. The absolute average accuracy of the navigator channel to predict the 1D SI and AP motions of the liver was less than 0.11, which is less than the out-of-plane image voxel size, 0.25 cm. This 1D information was then used to adapt the 4D population motion model in the SI and AP directions to predict the patient specific liver motion. The absolute average residual error of the navigator channel technique to adapt the population motion to the patients’ specific motion was verified using three verification methods: (1) vessel bifurcation, (2) tumor center of mass, and (3) MORFEUS deformable algorithm. All three verification methods showed statistically similar results where the technique’s accuracy was approximately on the order of the voxel image sizes. This method has potential applications in online assessment of motion at the time of treatment to

  18. Unsteady aerodynamic modeling for arbitrary motions

    NASA Technical Reports Server (NTRS)

    Edwards, J. W.; Ashley, H.; Breakwell, J. V.

    1977-01-01

    A study is presented on the unsteady aerodynamic loads due to arbitrary motions of a thin wing and their adaptation for the calculation of response and true stability of aeroelastic modes. In an Appendix, the use of Laplace transform techniques and the generalized Theodorsen function for two-dimensional incompressible flow is reviewed. New applications of the same approach are shown also to yield airloads valid for quite general small motions. Numerical results are given for the two-dimensional supersonic case. Previously proposed approximate methods, starting from simple harmonic unsteady theory, are evaluated by comparison with exact results obtained by the present approach. The Laplace inversion integral is employed to separate the loads into 'rational' and 'nonrational' parts, of which only the former are involved in aeroelastic stability of the wing. Among other suggestions for further work, it is explained how existing aerodynamic computer programs may be adapted in a fairly straightforward fashion to deal with arbitrary transients.

  19. Ground motion data for International Collider models

    SciTech Connect

    Volk, J.T.; LeBrun, P.; Shiltsev, V.; Singatulin, S.; /Fermilab

    2007-11-01

    The proposed location for the International Linear Collider (ILC) in the Americas region is Fermilab in Batavia Illinois. If built at this location the tunnels would be located in the Galena Platteville shale at a depth of 100 or more meters below the surface. Studies using hydro static water levels and seismometers have been conducted in the MINOS hall and the LaFrange Mine in North Aurora Illinois to determine the level of ground motion. Both these locations are in the Galena Platteville shale and indicate the typical ground motion to be expected for the ILC. The data contains both natural and cultural noise. Coefficients for the ALT law are determined. Seismic measurements at the surface and 100 meters below the surface are presented.

  20. An Architectural Model of Visual Motion Understanding

    DTIC Science & Technology

    1989-08-01

    responsible for at least some long-range apparent motion phenomena (Watson and Ahumada , 19851. The logical conclusion to this line of argument would be to...x direction. This idea is the basis of the work by Heeger mentioned in the previous section. Watson and Ahumada [1985] propose computing the sum of...oscillates at a frequency related to local velocity. Watson and Ahumada provide a detailed description of how the filters are constructed and how

  1. On a PCA-based lung motion model

    PubMed Central

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

    2014-01-01

    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

  2. On a PCA-based lung motion model

    NASA Astrophysics Data System (ADS)

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

    2011-09-01

    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

  3. A true polar wander model for Neoproterozoic plate motions

    SciTech Connect

    Ripperdan, R.L. )

    1992-01-01

    Recent paleogeographic reconstructions for the interval 750--500 Ma (Neoproterozoic to Late Cambrian) require rapid rates of plate motion and/or rotation around an equatorial Euler pole to accommodate reconstructions for the Early Paleozoic. Motions of this magnitude appear to be very uncommon during the Phanerozoic. A model for plate motions based on the hypothesis that discrete intervals of rapid true polar wander (RTPW) occurred during the Neoproterozoic can account for the paleogeographic changes with minimum amounts of plate motion. The model uses the paleogeographic reconstructions of Hoffman (1991). The following constraints were applied during derivation of the model: (1) relative motions between major continental units were restricted to be combinations of great circle or small circle translations with Euler poles of rotation = spin axis; (2) maximum rates of relative translational plate motion were 0.2 m/yr. Based on these constraints, two separate sets of synthetic plate motion trajectories were determined. The sequence of events in both can be summarized as: (1) A rapid true polar wander event of ca 90[degree] rafting a supercontinent to the spin axis; (2) breakup of the polar supercontinent into two fragments, one with the Congo, West Africa, Amazonia, and Baltica cratons, the other with the Laurentia, East Gondwana, and Kalahari cratons; (3) great circle motion of the blocks towards the equator; (4) small circle motion leading to amalgamation of Gondwana and separation of Laurentia and Baltica. In alternative 1, rifting initiates between East Antarctica and Laurentia and one episode of RTPW is required. Alternative 2 requires two episodes of RTPW; and that rifting occurred first along the eastern margin and later along the western margin of Laurentia. Synthetic plate motion trajectories are compared to existing paleomagnetic and geological data, and implications of the model for paleoclimatic changes during the Neoproterozoic are discussed.

  4. Evaluation of residual abdominal tumour motion in carbon ion gated treatments through respiratory motion modelling.

    PubMed

    Meschini, Giorgia; Seregni, Matteo; Pella, Andrea; Ciocca, Mario; Fossati, Piero; Valvo, Francesca; Riboldi, Marco; Baroni, Guido

    2017-02-01

    At the Italian National Centre for Oncologic Hadrontherapy (CNAO) patients with upper-abdominal tumours are being treated with carbon ion therapy, adopting the respiratory gating technique in combination with layered rescanning and abdominal compression to mitigate organ motion. Since online imaging of the irradiated volume is not feasible, this study proposes a modelling approach for the estimation of residual motion of the target within the gating window. The model extracts a priori respiratory motion information from the planning 4DCT using deformable image registration (DIR), then combines such information with the external surrogate signal recorded during dose delivery. This provides estimation of a CT volume corresponding to any given respiratory phase measured during treatment. The method was applied for the retrospective estimation of tumour residual motion during irradiation, considering 16 patients treated at CNAO with the respiratory gating protocol. The estimated tumour displacement, calculated with respect to the reference end-exhale position, was always limited (average displacement is 0.32±0.65mm over all patients) and below the maximum motion defined in the treatment plan. This supports the hypothesis of target position reproducibility, which is the crucial assumption in the gating approach. We also demonstrated the use of the model as a simulation tool to establish a patient-specific relationship between residual motion and the width of the gating window. In conclusion, the implemented method yields an estimation of the repeatability of the internal anatomy configuration during gated treatments, which can be used for further studies concerning the dosimetric impact of the estimated residual organ motion.

  5. Local discretization method for overdamped Brownian motion on a potential with multiple deep wells

    NASA Astrophysics Data System (ADS)

    Nguyen, P. T. T.; Challis, K. J.; Jack, M. W.

    2016-11-01

    We present a general method for transforming the continuous diffusion equation describing overdamped Brownian motion on a time-independent potential with multiple deep wells to a discrete master equation. The method is based on an expansion in localized basis states of local metastable potentials that match the full potential in the region of each potential well. Unlike previous basis methods for discretizing Brownian motion on a potential, this approach is valid for periodic potentials with varying multiple deep wells per period and can also be applied to nonperiodic systems. We apply the method to a range of potentials and find that potential wells that are deep compared to five times the thermal energy can be associated with a discrete localized state while shallower wells are better incorporated into the local metastable potentials of neighboring deep potential wells.

  6. Local discretization method for overdamped Brownian motion on a potential with multiple deep wells.

    PubMed

    Nguyen, P T T; Challis, K J; Jack, M W

    2016-11-01

    We present a general method for transforming the continuous diffusion equation describing overdamped Brownian motion on a time-independent potential with multiple deep wells to a discrete master equation. The method is based on an expansion in localized basis states of local metastable potentials that match the full potential in the region of each potential well. Unlike previous basis methods for discretizing Brownian motion on a potential, this approach is valid for periodic potentials with varying multiple deep wells per period and can also be applied to nonperiodic systems. We apply the method to a range of potentials and find that potential wells that are deep compared to five times the thermal energy can be associated with a discrete localized state while shallower wells are better incorporated into the local metastable potentials of neighboring deep potential wells.

  7. Multiple-camera/motion stereoscopy for range estimation in helicopter flight

    NASA Technical Reports Server (NTRS)

    Smith, Phillip N.; Sridhar, Banavar; Suorsa, Raymond E.

    1993-01-01

    Aiding the pilot to improve safety and reduce pilot workload by detecting obstacles and planning obstacle-free flight paths during low-altitude helicopter flight is desirable. Computer vision techniques provide an attractive method of obstacle detection and range estimation for objects within a large field of view ahead of the helicopter. Previous research has had considerable success by using an image sequence from a single moving camera to solving this problem. The major limitations of single camera approaches are that no range information can be obtained near the instantaneous direction of motion or in the absence of motion. These limitations can be overcome through the use of multiple cameras. This paper presents a hybrid motion/stereo algorithm which allows range refinement through recursive range estimation while avoiding loss of range information in the direction of travel. A feature-based approach is used to track objects between image frames. An extended Kalman filter combines knowledge of the camera motion and measurements of a feature's image location to recursively estimate the feature's range and to predict its location in future images. Performance of the algorithm will be illustrated using an image sequence, motion information, and independent range measurements from a low-altitude helicopter flight experiment.

  8. Unsteady aerodynamic simulation of multiple bodies in relative motion: A prototype method

    NASA Technical Reports Server (NTRS)

    Meakin, Robert L.

    1989-01-01

    A prototype method for time-accurate simulation of multiple aerodynamic bodies in relative motion is presented. The method is general and features unsteady chimera domain decomposition techniques and an implicit approximately factored finite-difference procedure to solve the time-dependent thin-layer Navier-Stokes equations. The method is applied to a set of two- and three- dimensional test problems to establish spatial and temporal accuracy, quantify computational efficiency, and begin to test overall code robustness.

  9. Estimating joint kinematics from skin motion observation: modelling and validation.

    PubMed

    Wolf, Alon; Senesh, Merav

    2011-11-01

    Modelling of soft tissue motion is required in many areas, such as computer animation, surgical simulation, 3D motion analysis and gait analysis. In this paper, we will focus on the use of modelling of skin deformation during 3D motion analysis. The most frequently used method in 3D human motion analysis involves placing markers on the skin of the analysed segment which is composed of the rigid bone and the surrounding soft tissues. Skin and soft tissue deformations introduce a significant artefact which strongly influences the resulting bone position, orientation and joint kinematics. For this study, we used a statistical solid dynamics approach which is a combination of several previously reported tools: the point cluster technique (PCT) and a Kalman filter which was added to the PCT. The methods were tested and evaluated on controlled human-arm motions, using an optical motion capture system (Vicon(TM)). The addition of a Kalman filter to the PCT for rigid body motion estimation results in a smoother signal that better represents the joint motion. Calculations indicate less signal distortion than when using a digital low-pass filter. Furthermore, adding a Kalman filter to the PCT substantially reduces the dispersion of the maximal and minimal instantaneous frequencies. For controlled human movements, the result indicated that adding a Kalman filter to the PCT produced a more accurate signal. However, it could not be concluded that the proposed Kalman filter is better than a low-pass filter for estimation of the motion. We suggest that implementation of a Kalman filter with a better biomechanical motion model will be more likely to improve the results.

  10. Multiple Model Methods for Cost Function Based Multiple Hypothesis Trackers

    DTIC Science & Technology

    2006-03-01

    MHT’s Gaussian mixture with Multiple Model Adaptive Estimators (MMAEs) or Interacting Multiple Model (IMM) estimators, and replacing the elemental...Kalman Filtering . . . . . . . . . . . . . . . . . . . . . . . . . 2-2 2.3.1 Dynamics Design Models . . . . . . . . . . . . . . . 2-3 2.3.2 Propagation ...Track Life of Various Merging and Pruning Algorithms . . 2-30 3.1. Constant Velocity Truth Model Driven by White Gaussian Noise . . 3-3 3.2. Constant

  11. Models of Multiple System Atrophy

    PubMed Central

    Fellner, Lisa; Wenning, Gregor K.; Stefanova, Nadia

    2016-01-01

    Multiple system atrophy (MSA) is a predominantly sporadic, adult-onset, fatal neurodegenerative disease of unknown etiology. MSA is characterized by autonomic failure, levodopa-unresponsive parkinsonism, cerebellar ataxia and pyramidal signs in any combination. MSA belongs to a group of neurodegenerative disorders termed α-synucleinopathies, which also include Parkinson’s disease and dementia with Lewy bodies. Their common pathological feature is the occurrence of abnormal α-synuclein positive inclusions in neurons or glial cells. In MSA, the main cell type presenting aggregates composed of α-synuclein are oligodendroglial cells. This pathological hallmark, also called glial cytoplasmic inclusions (GCIs), is associated with progressive and profound neuronal loss in various regions of the brain. The development of animal models of MSA is justified by the limited understanding of the mechanisms of neurodegeneration and GCIs formation, which is paralleled by a lack of therapeutic strategies. Two main types of rodent models have been generated to replicate different features of MSA neuropathology. On one hand, neurotoxin-based models have been produced to reproduce neuronal loss in substantia nigra pars compacta and striatum. On the other hand, transgenic mouse models with overexpression of α-synuclein in oligodendroglia have been used to reproduce GCIs-related pathology. This chapter gives an overview of the atypical Parkinson’s syndrome MSA and summarizes the currently available MSA animal models and their relevance for pre-clinical testing of disease-modifying therapies. PMID:24338664

  12. Occurrence pattern and direction of motion of multiple X-lines at the dayside magnetopause

    NASA Astrophysics Data System (ADS)

    Hoshi, Y.; Hasegawa, H.; Kitamura, N.; Saito, Y.

    2016-12-01

    Magnetic reconnection at the Earth's dayside magnetopause is a fundamental mechanism that transfers mass, momentum, and energy of the solar wind into Earth's magnetosphere. Time-dependent magnetic reconnection in the presence of multiple X-lines generates a closed magnetic field structure called flux rope. In this manner, multiple X-lines may reduce the amount of open magnetic flux and affect the efficiency of the solar wind energy transfer. However, the occurrence pattern of multiple X-lines is not clear. Furthermore, it is still unknown where the magnetic energy stored in flux ropes flanked by active X-lines goes. We statistically investigated the occurrence pattern and motion of direction of multiple X-lines observed at the dayside magnetopause, based on plasma and magnetic field data from the THEMIS spacecraft. The five THEMIS spacecraft have observed Earth's magnetosphere since launched in 2007, although THEMIS-B and -C observed the region only until 2010. We used THEMIS data taken in the dayside magnetopause region within the magnetic local time range from 6 to 18 hours. In-situ measurement around the center of a flux rope flanked by active X-lines shows a flow reversal with the flow speed exceeding 150 km/s relative to the magnetosheath flow speed, which is of the order of the local Alfven speed in the magnetosheath, bidirectional field-aligned fluxes of heated electrons on the magnetosheath side, an enhancement of the total pressure of order a few nPa, and bipolar change in the magnetic field component normal to the magnetopause. More than 100 events that have these characteristics are chosen as candidates and are used to estimate the direction of flux rope motion. We discuss effects of the IMF clock angle and geomagnetic dipole tilt angle on the occurrence position and direction of motion of multiple X-lines.

  13. Modeling of earthquake ground motion in the frequency domain

    NASA Astrophysics Data System (ADS)

    Thrainsson, Hjortur

    In recent years, the utilization of time histories of earthquake ground motion has grown considerably in the design and analysis of civil structures. It is very unlikely, however, that recordings of earthquake ground motion will be available for all sites and conditions of interest. Hence, there is a need for efficient methods for the simulation and spatial interpolation of earthquake ground motion. In addition to providing estimates of the ground motion at a site using data from adjacent recording stations, spatially interpolated ground motions can also be used in design and analysis of long-span structures, such as bridges and pipelines, where differential movement is important. The objective of this research is to develop a methodology for rapid generation of horizontal earthquake ground motion at any site for a given region, based on readily available source, path and site characteristics, or (sparse) recordings. The research includes two main topics: (i) the simulation of earthquake ground motion at a given site, and (ii) the spatial interpolation of earthquake ground motion. In topic (i), models are developed to simulate acceleration time histories using the inverse discrete Fourier transform. The Fourier phase differences, defined as the difference in phase angle between adjacent frequency components, are simulated conditional on the Fourier amplitude. Uniformly processed recordings from recent California earthquakes are used to validate the simulation models, as well as to develop prediction formulas for the model parameters. The models developed in this research provide rapid simulation of earthquake ground motion over a wide range of magnitudes and distances, but they are not intended to replace more robust geophysical models. In topic (ii), a model is developed in which Fourier amplitudes and Fourier phase angles are interpolated separately. A simple dispersion relationship is included in the phase angle interpolation. The accuracy of the interpolation

  14. Motion.

    ERIC Educational Resources Information Center

    Brand, Judith, Ed.

    2002-01-01

    This issue of Exploratorium Magazine focuses on the topic of motion. Contents include: (1) "First Word" (Zach Tobias); (2) "Cosmic Collisions" (Robert Irion); (3) "The Mobile Cell" (Karen E. Kalumuck); (4) "The Paths of Paths" (Steven Vogel); (5) "Fragments" (Pearl Tesler); (6) "Moving Pictures" (Amy Snyder); (7) "Plants on the Go" (Katharine…

  15. Motion.

    ERIC Educational Resources Information Center

    Gerhart, James B.; Nussbaum, Rudi H.

    This monograph was written for the Conference on the New Instructional Materials in Physics held at the University of Washington in summer, 1965. It is intended for use in an introductory course in college physics. It consists of an extensive qualitative discussion of motion followed by a detailed development of the quantitative methods needed to…

  16. Motion.

    ERIC Educational Resources Information Center

    Brand, Judith, Ed.

    2002-01-01

    This issue of Exploratorium Magazine focuses on the topic of motion. Contents include: (1) "First Word" (Zach Tobias); (2) "Cosmic Collisions" (Robert Irion); (3) "The Mobile Cell" (Karen E. Kalumuck); (4) "The Paths of Paths" (Steven Vogel); (5) "Fragments" (Pearl Tesler); (6) "Moving Pictures" (Amy Snyder); (7) "Plants on the Go" (Katharine…

  17. Satellite attitude motion models for capture and retrieval investigations

    NASA Technical Reports Server (NTRS)

    Cochran, John E., Jr.; Lahr, Brian S.

    1986-01-01

    The primary purpose of this research is to provide mathematical models which may be used in the investigation of various aspects of the remote capture and retrieval of uncontrolled satellites. Emphasis has been placed on analytical models; however, to verify analytical solutions, numerical integration must be used. Also, for satellites of certain types, numerical integration may be the only practical or perhaps the only possible method of solution. First, to provide a basis for analytical and numerical work, uncontrolled satellites were categorized using criteria based on: (1) orbital motions, (2) external angular momenta, (3) internal angular momenta, (4) physical characteristics, and (5) the stability of their equilibrium states. Several analytical solutions for the attitude motions of satellite models were compiled, checked, corrected in some minor respects and their short-term prediction capabilities were investigated. Single-rigid-body, dual-spin and multi-rotor configurations are treated. To verify the analytical models and to see how the true motion of a satellite which is acted upon by environmental torques differs from its corresponding torque-free motion, a numerical simulation code was developed. This code contains a relatively general satellite model and models for gravity-gradient and aerodynamic torques. The spacecraft physical model for the code and the equations of motion are given. The two environmental torque models are described.

  18. New Models of Mechanisms for the Motion Transformation

    NASA Astrophysics Data System (ADS)

    Petrović, Tomislav; Ivanov, Ivan

    In this paper two new mechanisms for the motion transformations are presented: screw mechanism for the transformation of one-way circular into two-way linear motion with impulse control and worm-planetary gear train with extremely height gear ratio. Both mechanisms represent new models of construction solutions for which patent protection has been achieved. These mechanisms are based on the application of the differential gearbox with two degrees of freedom. They are characterized by series of kinematic impacts at motion transformation and the possibility of temporary or permanent changes in the structure by subtracting the redundant degree of freedom. Thus the desired characteristic of the motion transformation is achieved. For each mechanism separately the principles of motion and transformation are described and the basic equations that describe the interdependence of geometric and kinematic and kinetic parameters of the system dynamics are given. The basic principles of controlling new mechanisms for motion transformation have been pointed to and the basic constructional performances which may find practical application have been given. The physical models of new systems of motion transformation have been designed and their operation has been presented. Performed experimental researches confirmed the theoretical results and very favorable kinematic characteristics of the mechanisms.

  19. Spherical shell model description of rotational motion

    NASA Astrophysics Data System (ADS)

    Zuker, A. P.; Retamosa, J.; Poves, A.; Caurier, E.

    1995-10-01

    Exact diagonalizations with a realistic interaction show that configurations with four neutrons in a major shell and four protons in another-or the same-major shell, behave systematically as backbending rotors. The dominance of the q.q component of the interaction is related to an approximate ``quasi-SU3'' symmetry. It is suggested that the onset of rotational motion in the rare earth nuclei is due to the promotion of the eight particle blocks to the major shells above the ones currently filling. Assuming a ``pseudo-SU3'' coupling for the particles in the lower orbits, it is possible to account remarkably well for the observed B(E2) rates at the beginning of the region.

  20. Detecting abandoned objects using interacting multiple models

    NASA Astrophysics Data System (ADS)

    Becker, Stefan; Münch, David; Kieritz, Hilke; Hübner, Wolfgang; Arens, Michael

    2015-10-01

    In recent years, the wide use of video surveillance systems has caused an enormous increase in the amount of data that has to be stored, monitored, and processed. As a consequence, it is crucial to support human operators with automated surveillance applications. Towards this end an intelligent video analysis module for real-time alerting in case of abandoned objects in public spaces is proposed. The overall processing pipeline consists of two major parts. First, person motion is modeled using an Interacting Multiple Model (IMM) filter. The IMM filter estimates the state of a person according to a finite-state, discrete-time Markov chain. Second, the location of persons that stay at a fixed position defines a region of interest, in which a nonparametric background model with dynamic per-pixel state variables identifies abandoned objects. In case of a detected abandoned object, an alarm event is triggered. The effectiveness of the proposed system is evaluated on the PETS 2006 dataset and the i-Lids dataset, both reflecting prototypical surveillance scenarios.

  1. The Long Decay Model of One-Dimensional Projectile Motion

    ERIC Educational Resources Information Center

    Lattery, Mark Joseph

    2008-01-01

    This article introduces a research study on student model formation and development in introductory mechanics. As a point of entry, I present a detailed analysis of the Long Decay Model of one-dimensional projectile motion. This model has been articulated by Galileo ("in De Motu") and by contemporary students. Implications for instruction are…

  2. Motion in Brane World Models: The Bazanski Approach

    SciTech Connect

    Kahil, M.E.

    2007-11-20

    Recently, path equations have been obtained for charged and spinning objects in brane world models, using a modified Bazanski Lagrangian. In this study, path deviation equations of extended objects are derived. The significance of moving extended objects in brane world models is examined. Motion in non-symmetric brane world models is also considered.

  3. The Long Decay Model of One-Dimensional Projectile Motion

    ERIC Educational Resources Information Center

    Lattery, Mark Joseph

    2008-01-01

    This article introduces a research study on student model formation and development in introductory mechanics. As a point of entry, I present a detailed analysis of the Long Decay Model of one-dimensional projectile motion. This model has been articulated by Galileo ("in De Motu") and by contemporary students. Implications for instruction are…

  4. Manipulating antiferromagnets with magnetic fields: Ratchet motion of multiple domain walls induced by asymmetric field pulses

    NASA Astrophysics Data System (ADS)

    Gomonay, O.; Kläui, M.; Sinova, J.

    2016-10-01

    Future applications of antiferromagnets (AFs) in many spintronics devices rely on the precise manipulation of domain walls. The conventional approach using static magnetic fields is inefficient due to the low susceptibility of AFs. Recently proposed electrical manipulation with spin-orbit torques is restricted to metals with a specific crystal structure. Here, we propose an alternative, broadly applicable approach: using asymmetric magnetic field pulses to induce controlled ratchet motion of AF domain walls. The efficiency of this approach is based on three peculiarities of AF dynamics. First, a time-dependent magnetic field couples with an AF order parameter stronger than a static magnetic field, which leads to higher mobility of the domain walls. Second, the rate of change of the magnetic field couples with the spatial variation of the AF order parameter inside the domain, and this enables a synchronous motion of multiple domain walls with the same structure. Third, tailored asymmetric field pulses in combination with static friction can prevent backward motion of domain walls and thus lead to the desired controlled ratchet effect. The proposed use of an external field, rather than internal spin-orbit torques, avoids any restrictions on size, conductivity, and crystal structure of the AF material. We believe that our approach paves a way for the development of AF-based devices based on the controlled motion of AF domain walls.

  5. An Approach to Automatic Motion Synthesis Harmonized with Music for Multiple Objects

    NASA Astrophysics Data System (ADS)

    Wang, Qi; Nakatani, Mie; Nishida, Shogo

    This paper proposed a research approach to automatic choreography synthesis based on SMF(Standard Midi File) for multiple animated figures. Based on the K.Hevner’s theory, 8 types of emotion in each beat can be extracted from music structure elements, such as tempo, key, rythm, melody, harmony, pitch, which can be computed from SMF. The time of one beat is limited to transmit the emotion to human. By the analysis of emotion, a music can be integrated to several time intervals, every which includes several continuous beats. The top value of synthetic emotion vector represents the emotion type of the interval. Based on the experiment result of C.Matsumoto, 14 motion factors can be mapped from the emotion of interval. According to the 14 motion factors, the macro-motions at the terminals of every interval, and the micromotions between every interval can be generated by mapping rules. We made a prototype system and did a subjective evaluation experiment. The result is fairly good at the congruity between generated motions and given emotion music. A successful research to solve these issues should lead to aid the designation of 3DCG animation.

  6. Folded Elastic Strip-Based Triboelectric Nanogenerator for Harvesting Human Motion Energy for Multiple Applications.

    PubMed

    Kang, Yue; Wang, Bo; Dai, Shuge; Liu, Guanlin; Pu, Yanping; Hu, Chenguo

    2015-09-16

    A folded elastic strip-based triboelectric nanogenerator (FS-TENG) made from two folded double-layer elastic strips of Al/PET and PTFE/PET can achieve multiple functions by low frequency mechanical motion. A single FS-TENG with strip width of 3 cm and length of 27 cm can generate a maximum output current, open-circuit voltage, and peak power of 55 μA, 840 V, and 7.33 mW at deformation frequency of 4 Hz with amplitude of 2.5 cm, respectively. This FS-TENG can work as a weight sensor due to its good elasticity. An integrated generator assembled by four FS-TENGs (IFS-TENG) can harvest the energy of human motion like flapping hands and walking steps. In addition, the IFS-TENG combined with electromagnetically induced electricity can achieve a completely self-driven doorbell with flashing lights. Moreover, a box-like generator integrated by four IFS-TENGs inside can work in horizontal or random motion modes and can be improved to harvest energy in all directions. This work promotes the research of completely self-driven systems and energy harvesting of human motion for applications in our daily life.

  7. Chaotic Motion in a Nonlinear Car Model Excited by Multi-frequency Road Surface Profile

    NASA Astrophysics Data System (ADS)

    CHEN, Yuexia; CHEN, Long; XU, Xing; WANG, Ruochen; YANG, Xiaofeng

    2017-05-01

    In order to solve the problem that existing nonlinear suspension models have not considered chaotic motion in primary and other resonances, and numerical calculation model is too simplified to capture the accurate critical conditions for the chaotic motion, a nonlinear suspension model and its new paths of chaos are investigated. Primary resonances, secondary resonances, and combined resonances are performed using multiple-time scales method. Based on the Melnikov functions, the critical conditions for the chaotic motion of the nonlinear system are found, which is 0.246 7 for the primary resonance, and 0.338 8 for the secondary resonance. The effects of parameters on chaotic range are considered, and results show that nonlinear stiffness of suspension k 2 has the largest impact on the chaotic range while damping coefficient C 1 has the smallest one. The chaotic responses on the area of the primary and secondary resonances are discussed via Lyapunov exponents and numerical integration of the equations of motion. It is found from Lyapunov exponents and Poincaré maps that motions are chaos over critical conditions, and has shown two very different paths of chaos on the primary and secondary resonances. Chaotic motion patterns in the primary and secondary resonances are obtained with more accurate critical conditions, which is a necessary complement to nonlinear study in nonlinear suspension mode.

  8. A model describing vestibular detection of body sway motion.

    NASA Technical Reports Server (NTRS)

    Nashner, L. M.

    1971-01-01

    An experimental technique was developed which facilitated the formulation of a quantitative model describing vestibular detection of body sway motion in a postural response mode. All cues, except vestibular ones, which gave a subject an indication that he was beginning to sway, were eliminated using a specially designed two-degree-of-freedom platform; body sway was then induced and resulting compensatory responses at the ankle joints measured. Hybrid simulation compared the experimental results with models of the semicircular canals and utricular otolith receptors. Dynamic characteristics of the resulting canal model compared closely with characteristics of models which describe eye movement and subjective responses to body rotational motions. The average threshold level, in the postural response mode, however, was considerably lower. Analysis indicated that the otoliths probably play no role in the initial detection of body sway motion.

  9. A model describing vestibular detection of body sway motion.

    NASA Technical Reports Server (NTRS)

    Nashner, L. M.

    1971-01-01

    An experimental technique was developed which facilitated the formulation of a quantitative model describing vestibular detection of body sway motion in a postural response mode. All cues, except vestibular ones, which gave a subject an indication that he was beginning to sway, were eliminated using a specially designed two-degree-of-freedom platform; body sway was then induced and resulting compensatory responses at the ankle joints measured. Hybrid simulation compared the experimental results with models of the semicircular canals and utricular otolith receptors. Dynamic characteristics of the resulting canal model compared closely with characteristics of models which describe eye movement and subjective responses to body rotational motions. The average threshold level, in the postural response mode, however, was considerably lower. Analysis indicated that the otoliths probably play no role in the initial detection of body sway motion.

  10. Superintegrability of geodesic motion on the sausage model

    NASA Astrophysics Data System (ADS)

    Arutyunov, Gleb; Heinze, Martin; Medina-Rincon, Daniel

    2017-06-01

    Reduction of the η-deformed sigma model on AdS_5× S5 to the two-dimensional squashed sphere (S^2)η can be viewed as a special case of the Fateev sausage model where the coupling constant ν is imaginary. We show that geodesic motion in this model is described by a certain superintegrable mechanical system with four-dimensional phase space. This is done by means of explicitly constructing three integrals of motion which satisfy the sl(2) Poisson algebra relations, albeit being non-polynomial in momenta. Further, we find a canonical transformation which transforms the Hamiltonian of this mechanical system to the one describing the geodesic motion on the usual two-sphere. By inverting this transformation we map geodesics on this auxiliary two-sphere back to the sausage model. This paper is a tribute to the memory of Prof Petr Kulish.

  11. Local harmonic motion monitoring of focused ultrasound surgery--a simulation model.

    PubMed

    Heikkilä, Janne; Curiel, Laura; Hynynen, Kullervo

    2010-01-01

    In this paper, a computational model for localized harmonic motion (LHM) imaging-based monitoring of high-intensity focused ultrasound surgery (FUS) is presented. The LHM technique is based on a focused, time-varying ultrasound radiation force excitation, which induces local oscillatory motions at the focal region. These vibrations are tracked, using pulse-echo imaging, and then, used to estimate the mechanical properties of the sonication region. LHM is feasible for FUS monitoring because changes in the material properties during the coagulation process affect the measured displacements. The presented model includes separate models to simulate acoustic sonication fields, sonication-induced temperature elevation and mechanical motion, and pulse-echo imaging of the induced motions. These 3-D simulation models are based on Rayleigh-Sommerfield integral, finite element, and spatial impulse response methods. Simulated-tissue temperature elevation and mechanical motion were compared with previously published in vivo measurements. Finally, the simulation model was used to simulate coagulation and LHM monitoring, as would occur with multiple, neighbouring sonication locations covering a large tumor.

  12. Modeling rate sensitivity of exercise transient responses to limb motion.

    PubMed

    Yamashiro, Stanley M; Kato, Takahide

    2014-10-01

    Transient responses of ventilation (V̇e) to limb motion can exhibit predictive characteristics. In response to a change in limb motion, a rapid change in V̇e is commonly observed with characteristics different than during a change in workload. This rapid change has been attributed to a feed-forward or adaptive response. Rate sensitivity was explored as a specific hypothesis to explain predictive V̇e responses to limb motion. A simple model assuming an additive feed-forward summation of V̇e proportional to the rate of change of limb motion was studied. This model was able to successfully account for the adaptive phase correction observed during human sinusoidal changes in limb motion. Adaptation of rate sensitivity might also explain the reduction of the fast component of V̇e responses previously reported following sudden exercise termination. Adaptation of the fast component of V̇e response could occur by reduction of rate sensitivity. Rate sensitivity of limb motion was predicted by the model to reduce the phase delay between limb motion and V̇e response without changing the steady-state response to exercise load. In this way, V̇e can respond more quickly to an exercise change without interfering with overall feedback control. The asymmetry between responses to an incremental and decremental ramp change in exercise can also be accounted for by the proposed model. Rate sensitivity leads to predicted behavior, which resembles responses observed in exercise tied to expiratory reserve volume. Copyright © 2014 the American Physiological Society.

  13. The Moon Also Rises: Investigating Celestial Motion Models.

    ERIC Educational Resources Information Center

    Barton, Andrea M.

    2001-01-01

    Introduces a high school science curriculum that embodies inquiry-based genetics, evolution, and astronomy. Presents two astronomy units of scientific modeling. The first activity involves a black box to explain a hidden mechanism's effect on the outflow of water. The second activity involves the development of celestial motion models to explain…

  14. Model for the computation of self-motion in biological systems

    NASA Technical Reports Server (NTRS)

    Perrone, John A.

    1992-01-01

    A technique is presented by which direction- and speed-tuned cells, such as those commonly found in the middle temporal region of the primate brain, can be utilized to analyze the patterns of retinal image motion that are generated during observer movement through the environment. The developed model determines heading by finding the peak response in a population of detectors or neurons each tuned to a particular heading direction. It is suggested that a complex interaction of multiple cell networks is required for the solution of the self-motion problem in the primate brain.

  15. Elements of an improved model of debris‐flow motion

    USGS Publications Warehouse

    Iverson, Richard M.

    2009-01-01

    A new depth‐averaged model of debris‐flow motion describes simultaneous evolution of flow velocity and depth, solid and fluid volume fractions, and pore‐fluid pressure. Non‐hydrostatic pore‐fluid pressure is produced by dilatancy, a state‐dependent property that links the depth‐averaged shear rate and volumetric strain rate of the granular phase. Pore‐pressure changes caused by shearing allow the model to exhibit rate‐dependent flow resistance, despite the fact that the basal shear traction involves only rate‐independent Coulomb friction. An analytical solution of simplified model equations shows that the onset of downslope motion can be accelerated or retarded by pore‐pressure change, contingent on whether dilatancy is positive or negative. A different analytical solution shows that such effects will likely be muted if downslope motion continues long enough, because dilatancy then evolves toward zero, and volume fractions and pore pressure concurrently evolve toward steady states.

  16. Turbulent motion of mass flows. Mathematical modeling

    NASA Astrophysics Data System (ADS)

    Eglit, Margarita; Yakubenko, Alexander; Yakubenko, Tatiana

    2016-04-01

    New mathematical models for unsteady turbulent mass flows, e.g., dense snow avalanches and landslides, are presented. Such models are important since most of large scale flows are turbulent. In addition to turbulence, the two other important points are taken into account: the entrainment of the underlying material by the flow and the nonlinear rheology of moving material. The majority of existing models are based on the depth-averaged equations and the turbulent character of the flow is accounted by inclusion of drag proportional to the velocity squared. In this paper full (not depth-averaged) equations are used. It is assumed that basal entrainment takes place if the bed friction equals the shear strength of the underlying layer (Issler D, M. Pastor Peréz. 2011). The turbulent characteristics of the flow are calculated using a three-parameter differential model (Lushchik et al., 1978). The rheological properties of moving material are modeled by one of the three types of equations: 1) Newtonian fluid with high viscosity, 2) power-law fluid and 3) Bingham fluid. Unsteady turbulent flows down long homogeneous slope are considered. The flow dynamical parameters and entrainment rate behavior in time as well as their dependence on properties of moving and underlying materials are studied numerically. REFERENCES M.E. Eglit and A.E. Yakubenko, 2014. Numerical modeling of slope flows entraining bottom material. Cold Reg. Sci. Technol., 108, 139-148 Margarita E. Eglit and Alexander E. Yakubenko, 2016. The effect of bed material entrainment and non-Newtonian rheology on dynamics of turbulent slope flows. Fluid Dynamics, 51(3) Issler D, M. Pastor Peréz. 2011. Interplay of entrainment and rheology in snow avalanches; a numerical study. Annals of Glaciology, 52(58), 143-147 Lushchik, V.G., Paveliev, A.A. , and Yakubenko, A.E., 1978. Three-parameter model of shear turbulence. Fluid Dynamics, 13, (3), 350-362

  17. Designing the optimal convolution kernel for modeling the motion blur

    NASA Astrophysics Data System (ADS)

    Jelinek, Jan

    2011-06-01

    Motion blur acts on an image like a two dimensional low pass filter, whose spatial frequency characteristic depends both on the trajectory of the relative motion between the scene and the camera and on the velocity vector variation along it. When motion during exposure is permitted, the conventional, static notions of both the image exposure and the scene-toimage mapping become unsuitable and must be revised to accommodate the image formation dynamics. This paper develops an exact image formation model for arbitrary object-camera relative motion with arbitrary velocity profiles. Moreover, for any motion the camera may operate in either continuous or flutter shutter exposure mode. Its result is a convolution kernel, which is optimally designed for both the given motion and sensor array geometry, and hence permits the most accurate computational undoing of the blurring effects for the given camera required in forensic and high security applications. The theory has been implemented and a few examples are shown in the paper.

  18. Current plate motions. [continental groupings and global modelling

    NASA Technical Reports Server (NTRS)

    Demets, C.; Gordon, R. G.; Argus, D. F.; Stein, S.

    1990-01-01

    A global plate motion model, named NUVEL-1, which describes current plate motions between 12 rigid plates is described, with special attention given to the method, data, and assumptions used. Tectonic implications of the patterns that emerged from the results are discussed. It is shown that wide plate boundary zones can form not only within the continental lithosphere but also within the oceanic lithosphere; e.g., between the Indian and Australian plates and between the North American and South American plates. Results of the model also suggest small but significant diffuse deformation of the oceanic lithosphere, which may be confined to small awkwardly shaped salients of major plates.

  19. A New Conflict Resolution Method for Multiple Mobile Robots in Cluttered Environments With Motion-Liveness.

    PubMed

    Shahriari, Mohammadali; Biglarbegian, Mohammad

    2016-12-09

    This paper presents a new conflict resolution methodology for multiple mobile robots while ensuring their motion-liveness, especially for cluttered and dynamic environments. Our method constructs a mathematical formulation in a form of an optimization problem by minimizing the overall travel times of the robots subject to resolving all the conflicts in their motion. This optimization problem can be easily solved through coordinating only the robots' speeds. To overcome the computational cost in executing the algorithm for very cluttered environments, we develop an innovative method through clustering the environment into independent subproblems that can be solved using parallel programming techniques. We demonstrate the scalability of our approach through performing extensive simulations. Simulation results showed that our proposed method is capable of resolving the conflicts of 100 robots in less than 1.23 s in a cluttered environment that has 4357 intersections in the paths of the robots. We also developed an experimental testbed and demonstrated that our approach can be implemented in real time. We finally compared our approach with other existing methods in the literature both quantitatively and qualitatively. This comparison shows while our approach is mathematically sound, it is more computationally efficient, scalable for very large number of robots, and guarantees the live and smooth motion of robots.

  20. Orthographic Perspective Mappings for Consistent Wide-Area Motion Feature Maps from Multiple Cameras.

    PubMed

    O'Gorman, Lawrence; Yang, Guang

    2016-04-15

    Spatiotemporal activity maps have been used to visualize where activity occurs over time, and are often displayed as pseudo-color heat maps. Our multi-dimensional activity map includes the following motion features: density, direction, bi-direction, velocity, and dwell. The primary contribution of this paper is to describe a set of mappings that will transform activity maps captured from cameras of different perspectives to ones from a single orthographic perspective. The purpose of this is to be able to view and compare multiple activity maps from different cameras views over a wide area with consistently comparable data. A second contribution is that most mappings are based upon statistically learned camera perspectives, to minimize manual camera calibration. We demonstrate mapping results with multiple video datasets and describe applications for visualization and wide-area spatial probability estimation.

  1. Physiological model of motion analysis for machine vision

    NASA Astrophysics Data System (ADS)

    Young, Richard A.; Lesperance, Ronald M.

    1993-09-01

    We studied the spatio-temporal shape of `receptive fields' of simple cells in the monkey visual cortex. Receptive fields are maps of the regions in space and time that affect a cell's electrical responses. Fields with no change in shape over time responded to all directions of motion; fields with changing shape over time responded to only some directions of motion. A Gaussian Derivative (GD) model fit these fields well, in a transformed variable space that aligned the centers and principal axes of the field and model in space-time. The model accounts for fields that vary in orientation, location, spatial scale, motion properties, and number of lobes. The model requires only ten parameters (the minimum possible) to describe fields in two dimensions of space and one of time. A difference-of-offset-Gaussians (DOOG) provides a plausible physiological means to form GD model fields. Because of its simplicity, the GD model improves the efficiency of machine vision systems for analyzing motion. An implementation produced robust local estimates of the direction and speed of moving objects in real scenes.

  2. The HAMP Signal Relay Domain Adopts Multiple Conformational States through Collective Piston and Tilt Motions

    PubMed Central

    Zhu, Lizhe; Bolhuis, Peter G.; Vreede, Jocelyne

    2013-01-01

    The HAMP domain is a linker region in prokaryotic sensor proteins and relays input signals to the transmitter domain and vice versa. Functional as a dimer, the structure of HAMP shows a parallel coiled-coil motif comprising four helices. To date, it is unclear how HAMP can relay signals from one domain to another, although several models exist. In this work, we use molecular simulation to test the hypothesis that HAMP adopts different conformations, one of which represents an active, signal-relaying configuration, and another an inactive, resting state. We first performed molecular dynamics simulation on the prototype HAMP domain Af1503 from Archaeoglobus fulgidus. We explored its conformational space by taking the structure of the A291F mutant disabling HAMP activity as a starting point. These simulations revealed additional conformational states that differ in the tilt angles between the helices as well as the relative piston shifts of the helices relative to each other. By enhancing the sampling in a metadynamics set up, we investigated three mechanistic models for HAMP signal transduction. Our results indicate that HAMP can access additional conformational states characterized by piston motion. Furthermore, the piston motion of the N-terminal helix of one monomer is directly correlated with the opposite piston motion of the C-terminal helix of the other monomer. The change in piston motion is accompanied by a change in tilt angle between the monomers, thus revealing that HAMP exhibits a collective motion, i.e. a combination of changes in tilt angles and a piston-like displacement. Our results provide insights into the conformational changes that underlie the signaling mechanism involving HAMP. PMID:23468603

  3. The HAMP signal relay domain adopts multiple conformational states through collective piston and tilt motions.

    PubMed

    Zhu, Lizhe; Bolhuis, Peter G; Vreede, Jocelyne

    2013-01-01

    The HAMP domain is a linker region in prokaryotic sensor proteins and relays input signals to the transmitter domain and vice versa. Functional as a dimer, the structure of HAMP shows a parallel coiled-coil motif comprising four helices. To date, it is unclear how HAMP can relay signals from one domain to another, although several models exist. In this work, we use molecular simulation to test the hypothesis that HAMP adopts different conformations, one of which represents an active, signal-relaying configuration, and another an inactive, resting state. We first performed molecular dynamics simulation on the prototype HAMP domain Af1503 from Archaeoglobus fulgidus. We explored its conformational space by taking the structure of the A291F mutant disabling HAMP activity as a starting point. These simulations revealed additional conformational states that differ in the tilt angles between the helices as well as the relative piston shifts of the helices relative to each other. By enhancing the sampling in a metadynamics set up, we investigated three mechanistic models for HAMP signal transduction. Our results indicate that HAMP can access additional conformational states characterized by piston motion. Furthermore, the piston motion of the N-terminal helix of one monomer is directly correlated with the opposite piston motion of the C-terminal helix of the other monomer. The change in piston motion is accompanied by a change in tilt angle between the monomers, thus revealing that HAMP exhibits a collective motion, i.e. a combination of changes in tilt angles and a piston-like displacement. Our results provide insights into the conformational changes that underlie the signaling mechanism involving HAMP.

  4. Subpopulation-based correspondence modelling for improved respiratory motion estimation in the presence of inter-fraction motion variations.

    PubMed

    Wilms, Matthias; Werner, René; Yamamoto, Tokihiro; Handels, Heinz; Ehrhardt, Jan

    2017-06-26

    Correspondence modelling between low-dimensional breathing signals and internal organ motion is a prerequisite for application of advanced techniques in radiotherapy of moving targets. Patient-specific correspondence models can, for example, be built prior to treatment based on a planning 4D CT and simultaneously acquired breathing signals. Reliability of pre-treatment-built models depends, however, on the degree of patient-specific inter-fraction motion variations. This study investigates whether motion estimation accuracy in the presence of inter-fraction motion variations can be improved using correspondence models that incorporate motion information from different patients. The underlying assumption is that inter-patient motion variations resemble patient-specific inter-fraction motion variations for subpopulations of patients with similar breathing characteristics. The hypothesis is tested by integrating a sparse manifold clustering approach into a regression-based correspondence modelling framework that allows for automated identification of patient subpopulations. The evaluation is based on a total of 73 lung 4D CT data sets, including two cohorts of patients with repeat 4D CT scans (cohort 1: 14 patients; cohort 2: ten patients). The results are consistent for both cohorts: The subpopulation-based modelling approach outperforms general population modelling (models built on all data sets available) as well as pre-treatment-built models trained on only the patient-specific motion information. The results thereby support the hypothesis and illustrate the potential of subpopulation-based correspondence modelling.

  5. Subpopulation-based correspondence modelling for improved respiratory motion estimation in the presence of inter-fraction motion variations

    NASA Astrophysics Data System (ADS)

    Wilms, Matthias; Werner, René; Yamamoto, Tokihiro; Handels, Heinz; Ehrhardt, Jan

    2017-07-01

    Correspondence modelling between low-dimensional breathing signals and internal organ motion is a prerequisite for application of advanced techniques in radiotherapy of moving targets. Patient-specific correspondence models can, for example, be built prior to treatment based on a planning 4D CT and simultaneously acquired breathing signals. Reliability of pre-treatment-built models depends, however, on the degree of patient-specific inter-fraction motion variations. This study investigates whether motion estimation accuracy in the presence of inter-fraction motion variations can be improved using correspondence models that incorporate motion information from different patients. The underlying assumption is that inter-patient motion variations resemble patient-specific inter-fraction motion variations for subpopulations of patients with similar breathing characteristics. The hypothesis is tested by integrating a sparse manifold clustering approach into a regression-based correspondence modelling framework that allows for automated identification of patient subpopulations. The evaluation is based on a total of 73 lung 4D CT data sets, including two cohorts of patients with repeat 4D CT scans (cohort 1: 14 patients; cohort 2: ten patients). The results are consistent for both cohorts: The subpopulation-based modelling approach outperforms general population modelling (models built on all data sets available) as well as pre-treatment-built models trained on only the patient-specific motion information. The results thereby support the hypothesis and illustrate the potential of subpopulation-based correspondence modelling.

  6. Hamilton-Jacobi modelling of relative motion for formation flying.

    PubMed

    Kolemen, Egemen; Kasdin, N Jeremy; Gurfil, Pini

    2005-12-01

    A precise analytic model for the relative motion of a group of satellites in slightly elliptic orbits is introduced. With this aim, we describe the relative motion of an object relative to a circular or slightly elliptic reference orbit in the rotating Hill frame via a low-order Hamiltonian, and solve the Hamilton-Jacobi equation. This results in a first-order solution to the relative motion identical to the Clohessy-Wiltshire approach; here, however, rather than using initial conditions as our constants of the motion, we utilize the canonical momenta and coordinates. This allows us to treat perturbations in an identical manner, as in the classical Delaunay formulation of the two-body problem. A precise analytical model for the base orbit is chosen with the included effect of zonal harmonics (J(2), J(3), J(4)). A Hamiltonian describing the real relative motion is formed and by differing this from the nominal Hamiltonian, the perturbing Hamiltonian is obtained. Using the Hamilton equations, the variational equations for the new constants are found. In a manner analogous to the center manifold reduction procedure, the non-periodic part of the motion is canceled through a magnitude analysis leading to simple boundedness conditions that cancel the drift terms due to the higher order perturbations. Using this condition, the variational equations are integrated to give periodic solutions that closely approximate the results from numerical integration (1 mm/per orbit for higher order and eccentricity perturbations and 30 cm/per orbit for zonal perturbations). This procedure provides a compact and insightful analytic description of the resulting relative motion.

  7. Coupled grain boundary motion in aluminium: the effect of structural multiplicity

    PubMed Central

    Cheng, Kuiyu; Zhang, Liang; Lu, Cheng; Tieu, Kiet

    2016-01-01

    The shear-induced coupled grain boundary motion plays an important role in the deformation of nanocrystalline (NC) materials. It has been known that the atomic structure of the grain boundary (GB) is not necessarily unique for a given set of misorientation and inclination of the boundary plane. However, the effect of the structural multiplicity of the GB on its coupled motion has not been reported. In the present study we investigated the structural multiplicity of the symmetric tilt Σ5(310) boundary in aluminium and its influence on the GB behaviour at a temperature range of 300 K–600 K using molecular dynamic simulations. Two starting atomic configurations were adopted in the simulations which resulted in three different GB structures at different temperatures. Under the applied shear deformation each GB structure exhibited its unique GB behaviour. A dual GB behaviour, namely the transformation of one GB behaviour to another during deformation, was observed for the second starting configuration at a temperature of 500 K. The atomistic mechanisms responsible for these behaviour were analysed in detail. The result of this study implicates a strong relationship between GB structures and their behaviour, and provides a further information of the grain boundary mediated plasticity in nanocrystalline materials. PMID:27140343

  8. Domain-wall motion in random potential and hysteresis modeling

    SciTech Connect

    Pasquale, M.; Basso, V.; Bertotti, G.; Jiles, D.C.; Bi, Y.

    1998-06-01

    Two different approaches to hysteresis modeling are compared using a common ground based on energy relations, defined in terms of dissipated and stored energy. Using the Preisach model and assuming that magnetization is mainly due to domain-wall motion, one can derive the expression of magnetization along a major loop typical of the Jiles{endash}Atherton model and then extend its validity to cases where mean-field effects and reversible contributions are present. {copyright} {ital 1998 American Institute of Physics.}

  9. Multiple Indicator Stationary Time Series Models.

    ERIC Educational Resources Information Center

    Sivo, Stephen A.

    2001-01-01

    Discusses the propriety and practical advantages of specifying multivariate time series models in the context of structural equation modeling for time series and longitudinal panel data. For time series data, the multiple indicator model specification improves on classical time series analysis. For panel data, the multiple indicator model…

  10. Multiple Indicator Stationary Time Series Models.

    ERIC Educational Resources Information Center

    Sivo, Stephen A.

    2001-01-01

    Discusses the propriety and practical advantages of specifying multivariate time series models in the context of structural equation modeling for time series and longitudinal panel data. For time series data, the multiple indicator model specification improves on classical time series analysis. For panel data, the multiple indicator model…

  11. Oceanic Excitations On Polar Motion: A Cross Comparison Among Models

    NASA Astrophysics Data System (ADS)

    Zhou, Y.; Chen, J.; Liao, X.; Wilson, C. R.

    2004-12-01

    Recent studies based on various oceanic general circulation models (OGCMs) demonstrated that the oceans are a major contributor to polar motion excitations. In this paper, we analyze and compare observed non-atmospheric polar motion excitations with oceanic angular momentum (OAM) variations determined from four OGCMs, which include the parallel ocean climate model (POCM), a barotropic ocean model (BOM), the Estimating the Circulation and Climate of the Ocean (ECCO) non-data-assimilating model (ECCO-NDA), and the ECCO data-assimilating model (ECCO-DA). The data to be analyzed span a 5-year¡_s overlapped period from 1993 to 1997. At annual time scale, these four OAM estimates do not agree well with each other, while POCM shows relatively larger discrepancies than other three models. At intraseasonal time scales, ECCO-DA yields the best agreement with observations, and reduces the variance of non-atmospheric excitations by about 60%, 10-20% more than those explained by other three models. However, at the very short periods of 4-20 days, the BOM estimates could explain about half of the observed variance, twice as much as that by ECCO-NDA, and also shows considerably better correlation with observations. Due to different modeling schemes and methods, significant discrepancies could arise with respect to the quantity of modeling large-scale oceanic mass redistribution and current variation. A clear understanding of global oceanic contributions to polar motion excitation still remains a challenge.

  12. Multi-modal gesture recognition using integrated model of motion, audio and video

    NASA Astrophysics Data System (ADS)

    Goutsu, Yusuke; Kobayashi, Takaki; Obara, Junya; Kusajima, Ikuo; Takeichi, Kazunari; Takano, Wataru; Nakamura, Yoshihiko

    2015-07-01

    Gesture recognition is used in many practical applications such as human-robot interaction, medical rehabilitation and sign language. With increasing motion sensor development, multiple data sources have become available, which leads to the rise of multi-modal gesture recognition. Since our previous approach to gesture recognition depends on a unimodal system, it is difficult to classify similar motion patterns. In order to solve this problem, a novel approach which integrates motion, audio and video models is proposed by using dataset captured by Kinect. The proposed system can recognize observed gestures by using three models. Recognition results of three models are integrated by using the proposed framework and the output becomes the final result. The motion and audio models are learned by using Hidden Markov Model. Random Forest which is the video classifier is used to learn the video model. In the experiments to test the performances of the proposed system, the motion and audio models most suitable for gesture recognition are chosen by varying feature vectors and learning methods. Additionally, the unimodal and multi-modal models are compared with respect to recognition accuracy. All the experiments are conducted on dataset provided by the competition organizer of MMGRC, which is a workshop for Multi-Modal Gesture Recognition Challenge. The comparison results show that the multi-modal model composed of three models scores the highest recognition rate. This improvement of recognition accuracy means that the complementary relationship among three models improves the accuracy of gesture recognition. The proposed system provides the application technology to understand human actions of daily life more precisely.

  13. Simulation Studies of the NLC with Improved Ground Motion Models

    SciTech Connect

    Seryi, Andrei

    2000-08-31

    The performance of various systems of the Next Linear Collider (NLC) have been studied in terms of ground motion using recently developed models. In particular, the performance of the beam delivery system is discussed. Plans to evaluate the operation of the main linac beam-based alignment and feedback systems are also outlined.

  14. Assessing the Validity of Multiple-Choice Questions in Measuring Fourth Graders' Ability to Interpret Graphs about Motion and Temperature

    ERIC Educational Resources Information Center

    Dulger, Mehmet; Deniz, Hasan

    2017-01-01

    The purpose of this paper is to assess the validity of multiple-choice questions in measuring fourth grade students' ability to interpret graphs related to physical science topics such as motion and temperature. We administered a test including 6 multiple-choice questions to 28 fourth grade students. Students were asked to explain their thinking…

  15. MetaTracker: integration and abstraction of 3D motion tracking data from multiple hardware systems

    NASA Astrophysics Data System (ADS)

    Kopecky, Ken; Winer, Eliot

    2014-06-01

    Motion tracking has long been one of the primary challenges in mixed reality (MR), augmented reality (AR), and virtual reality (VR). Military and defense training can provide particularly difficult challenges for motion tracking, such as in the case of Military Operations in Urban Terrain (MOUT) and other dismounted, close quarters simulations. These simulations can take place across multiple rooms, with many fast-moving objects that need to be tracked with a high degree of accuracy and low latency. Many tracking technologies exist, such as optical, inertial, ultrasonic, and magnetic. Some tracking systems even combine these technologies to complement each other. However, there are no systems that provide a high-resolution, flexible, wide-area solution that is resistant to occlusion. While frameworks exist that simplify the use of tracking systems and other input devices, none allow data from multiple tracking systems to be combined, as if from a single system. In this paper, we introduce a method for compensating for the weaknesses of individual tracking systems by combining data from multiple sources and presenting it as a single tracking system. Individual tracked objects are identified by name, and their data is provided to simulation applications through a server program. This allows tracked objects to transition seamlessly from the area of one tracking system to another. Furthermore, it abstracts away the individual drivers, APIs, and data formats for each system, providing a simplified API that can be used to receive data from any of the available tracking systems. Finally, when single-piece tracking systems are used, those systems can themselves be tracked, allowing for real-time adjustment of the trackable area. This allows simulation operators to leverage limited resources in more effective ways, improving the quality of training.

  16. Kinematic Model of River Ice Motion During Dynamic Breakup

    DTIC Science & Technology

    1993-09-01

    Texas: Gulf Publish- nal of Computational Physics, 101: 130-139. ing Co. Shen, H.T. and Y.C. Chen (1992) Lagrangian discrete Calkins , DJ. (1978...OTIC9 ~jjELECTE0 lV 919 3 AD-A273 141 * Kinematic Model of River Ice Motion During Dynamic Breakup Michael G . Ferrick, Patricia B. Weyrick and David...Bottom) Looking across the river during brash ice motion at about 1 m /s. (Photos by M . Ferrick.) For conversion of SI metric units to U.S./British

  17. Oceanic excitations on polar motion: a cross comparison among models

    NASA Astrophysics Data System (ADS)

    Zhou, Y. H.; Chen, J. L.; Liao, X. H.; Wilson, C. R.

    2005-08-01

    Recent studies based on various ocean general circulation models (OGCMs) demonstrate that the oceans are a major contributor to polar motion excitations. In this paper, we analyse and compare observed non-atmospheric polar motion excitations with oceanic angular momentum (OAM) variations determined from four OGCMs, which include the parallel ocean climate model (POCM), a barotropic ocean model (BOM), the Estimating the Circulation and Climate of the Ocean (ECCO) non-data-assimilating model (ECCO-NDA) and the ECCO data-assimilating model (ECCO-DA). The data to be analysed span a 5-yr overlapped period from 1993 to 1997. At annual timescale, considerable discrepancies exist between POCM and the other three models, which result mainly from differences in annual components of the forcing wind fields. At semi-annual timescale, however, POCM shows better phase agreement with observed non-atmospheric polar motion excitation than the other three ocean models. At intraseasonal timescales, ECCO-DA yields better agreement with observations, and reduces the variance of non-atmospheric excitations by ~60 per cent, 10-20 per cent more than those explained by the other three models. However, at the very short periods of 4-20 days, the BOM estimates could explain about half of the observed variance, twice as much as that by ECCO-NDA, and also shows considerably better correlation with observations. Due to different modelling schemes and methods, significant discrepancies could arise with respect to the quality of modelling large-scale oceanic mass redistribution and current variation. A complete understanding of global oceanic contributions to polar motion excitation still remains a challenge.

  18. Surrogate-driven deformable motion model for organ motion tracking in particle radiation therapy

    NASA Astrophysics Data System (ADS)

    Fassi, Aurora; Seregni, Matteo; Riboldi, Marco; Cerveri, Pietro; Sarrut, David; Battista Ivaldi, Giovanni; Tabarelli de Fatis, Paola; Liotta, Marco; Baroni, Guido

    2015-02-01

    The aim of this study is the development and experimental testing of a tumor tracking method for particle radiation therapy, providing the daily respiratory dynamics of the patient’s thoraco-abdominal anatomy as a function of an external surface surrogate combined with an a priori motion model. The proposed tracking approach is based on a patient-specific breathing motion model, estimated from the four-dimensional (4D) planning computed tomography (CT) through deformable image registration. The model is adapted to the interfraction baseline variations in the patient’s anatomical configuration. The driving amplitude and phase parameters are obtained intrafractionally from a respiratory surrogate signal derived from the external surface displacement. The developed technique was assessed on a dataset of seven lung cancer patients, who underwent two repeated 4D CT scans. The first 4D CT was used to build the respiratory motion model, which was tested on the second scan. The geometric accuracy in localizing lung lesions, mediated over all breathing phases, ranged between 0.6 and 1.7 mm across all patients. Errors in tracking the surrounding organs at risk, such as lungs, trachea and esophagus, were lower than 1.3 mm on average. The median absolute variation in water equivalent path length (WEL) within the target volume did not exceed 1.9 mm-WEL for simulated particle beams. A significant improvement was achieved compared with error compensation based on standard rigid alignment. The present work can be regarded as a feasibility study for the potential extension of tumor tracking techniques in particle treatments. Differently from current tracking methods applied in conventional radiotherapy, the proposed approach allows for the dynamic localization of all anatomical structures scanned in the planning CT, thus providing complete information on density and WEL variations required for particle beam range adaptation.

  19. Modeling Multiple Causes of Carcinogenesis

    SciTech Connect

    Jones, T D

    1999-01-24

    An array of epidemiological results and databases on test animal indicate that risk of cancer and atherosclerosis can be up- or down-regulated by diet through a range of 200%. Other factors contribute incrementally and include the natural terrestrial environment and various human activities that jointly produce complex exposures to endotoxin-producing microorganisms, ionizing radiations, and chemicals. Ordinary personal habits and simple physical irritants have been demonstrated to affect the immune response and risk of disease. There tends to be poor statistical correlation of long-term risk with single agent exposures incurred throughout working careers. However, Agency recommendations for control of hazardous exposures to humans has been substance-specific instead of contextually realistic even though there is consistent evidence for common mechanisms of toxicological and carcinogenic action. That behavior seems to be best explained by molecular stresses from cellular oxygen metabolism and phagocytosis of antigenic invasion as well as breakdown of normal metabolic compounds associated with homeostatic- and injury-related renewal of cells. There is continually mounting evidence that marrow stroma, comprised largely of monocyte-macrophages and fibroblasts, is important to phagocytic and cytokinetic response, but the complex action of the immune process is difficult to infer from first-principle logic or biomarkers of toxic injury. The many diverse database studies all seem to implicate two important processes, i.e., the univalent reduction of molecular oxygen and breakdown of aginuine, an amino acid, by hydrolysis or digestion of protein which is attendant to normal antigen-antibody action. This behavior indicates that protection guidelines and risk coefficients should be context dependent to include reference considerations of the composite action of parameters that mediate oxygen metabolism. A logic of this type permits the realistic common-scale modeling of

  20. Collective motion of cells: from experiments to models.

    PubMed

    Méhes, Előd; Vicsek, Tamás

    2014-09-01

    Swarming or collective motion of living entities is one of the most common and spectacular manifestations of living systems that have been extensively studied in recent years. A number of general principles have been established. The interactions at the level of cells are quite different from those among individual animals, therefore the study of collective motion of cells is likely to reveal some specific important features which we plan to overview in this paper. In addition to presenting the most appealing results from the quickly growing related literature we also deliver a critical discussion of the emerging picture and summarize our present understanding of collective motion at the cellular level. Collective motion of cells plays an essential role in a number of experimental and real-life situations. In most cases the coordinated motion is a helpful aspect of the given phenomenon and results in making a related process more efficient (e.g., embryogenesis or wound healing), while in the case of tumor cell invasion it appears to speed up the progression of the disease. In these mechanisms cells both have to be motile and adhere to one another, the adherence feature being the most specific to this sort of collective behavior. One of the central aims of this review is to present the related experimental observations and treat them in light of a few basic computational models so as to make an interpretation of the phenomena at a quantitative level as well.

  1. Polar motion excitation from several models of land hydrosphere

    NASA Astrophysics Data System (ADS)

    Nastula, Jolanta

    2017-04-01

    The impact of land hydrosphere mass variations on polar motion excitation is still not sufficiently estimated and not known as well as the role of the atmosphere and ocean. A comparison of the hydrological excitation function (Hydrological Angular Momentum - HAM) with observed geodetic excitation functions (GAM) is a common method of assessing of the influence of land hydrology on polar motion excitation function. HAM can be estimated either from global models of the land hydrosphere or from the Earth's gravity field variations. Our previous attempt to assess the role of land hydrology in the excitation balance using the hydrological angular momentum (HAM) estimates from Gravity Recovery and Climate Experiment (GRACE) data and hydrological models was not conclusive (Brzeziński et al., 2009, Nastula et al., 2011, Wińska et al., 2016). We found for example that gravimetric-hydrological excitation functions, based on the Gravity and Climate Recovery Experiment (GRACE) gravity fiels determined from the several processing centers differed significantly. Additionally hydrological excitation computed from different hydrological models differed significantly in amplitudes and phases. In this work we re - estimate hydrological polar motion excitation functions from several hydrological models and climate models and from GRACE gravity fields. Our investigations are focused on the influence of land hydrosphere on polar motion excitation functions at seasonal and non-seasonal time scales and comprises two steps: • first determinations hydrological excitation functions (HAM) from regional distribution of Terrestrial Water Storage (TWS). • the second comparison of the global HAM with hydrological signal in the observed geodetic excitation function of polar motion.

  2. A Personalized Biomechanical Model for Respiratory Motion Prediction

    PubMed Central

    Fuerst, B.; Mansi, T.; Zhang, Jianwen; Khurd, P.; Declerck, J.; Boettger, T.; Navab, Nassir; Bayouth, J.; Comaniciu, Dorin; Kamen, A.

    2014-01-01

    Time-resolved imaging of the thorax or abdominal area is affected by respiratory motion. Nowadays, one-dimensional respiratory surrogates are used to estimate the current state of the lung during its cycle, but with rather poor results. This paper presents a framework to predict the 3D lung motion based on a patient-specific finite element model of respiratory mechanics estimated from two CT images at end of inspiration (EI) and end of expiration (EE). We first segment the lung, thorax and sub-diaphragm organs automatically using a machine learning algorithm. Then, a biomechanical model of the lung, thorax and sub-diaphragm is employed to compute the 3D respiratory motion. Our model is driven by thoracic pressures, estimated automatically from the EE and EI images using a trust-region approach. Finally, lung motion is predicted by modulating the thoracic pressures. The effectiveness of our approach is evaluated by predicting lung deformation during exhale on five DIR-Lab datasets. Several personalization strategies are tested, showing that an average error of 3.88 ± 1.54mm in predicted landmark positions can be achieved. Since our approach is generative, it may constitute a 3D surrogate information for more accurate medical image reconstruction and patient respiratory analysis. PMID:23286176

  3. A personalized biomechanical model for respiratory motion prediction.

    PubMed

    Fuerst, B; Mansi, T; Zhang, Jianwen; Khurd, P; Declerck, J; Boettger, T; Navab, Nassir; Bayouth, J; Comaniciu, Dorin; Kamen, A

    2012-01-01

    Time-resolved imaging of the thorax or abdominal area is affected by respiratory motion. Nowadays, one-dimensional respiratory surrogates are used to estimate the current state of the lung during its cycle, but with rather poor results. This paper presents a framework to predict the 3D lung motion based on a patient-specific finite element model of respiratory mechanics estimated from two CT images at end of inspiration (EI) and end of expiration (EE). We first segment the lung, thorax and sub-diaphragm organs automatically using a machine-learning algorithm. Then, a biomechanical model of the lung, thorax and sub-diaphragm is employed to compute the 3D respiratory motion. Our model is driven by thoracic pressures, estimated automatically from the EE and EI images using a trust-region approach. Finally, lung motion is predicted by modulating the thoracic pressures. The effectiveness of our approach is evaluated by predicting lung deformation during exhale on five DIR-Lab datasets. Several personalization strategies are tested, showing that an average error of 3.88 +/- 1.54 mm in predicted landmark positions can be achieved. Since our approach is generative, it may constitute a 3D surrogate information for more accurate medical image reconstruction and patient respiratory analysis.

  4. Machine Visual Motion Detection Modeled On Vertebrate Retina

    NASA Astrophysics Data System (ADS)

    Blackburn, M. R.; Nguyen, H. G.; Kaomea, P. K.

    1988-12-01

    Real-time motion analysis would be very useful for autonomous undersea vehicle (AUV) navigation, target tracking, homing, and obstacle avoidance. The perception of motion is well developed in animals from insects to man, providing solutions to similar problems. We have therefore applied a model of the motion analysis subnetwork in the vertebrate retina to visual navigation in the AUV. The model is currently implemented in the C programming language as a discrete- time serial approximation of a continuous-time parallel process. Running on an IBM-PC/AT with digitized video camera images, the system can detect and describe motion in a 16 by 16 receptor field at the rate of 4 updates per second. The system responds accurately with direction and speed information to images moving across the visual field at velocities less than 8 degrees of visual angle per second at signal-to-noise ratios greater than 3. The architecture is parallel and its sparse connections do not require long-term modifications. The model is thus appropriate for implementation in VLSI optoelectronics.

  5. Multiple Imputation Strategies for Multiple Group Structural Equation Models

    ERIC Educational Resources Information Center

    Enders, Craig K.; Gottschall, Amanda C.

    2011-01-01

    Although structural equation modeling software packages use maximum likelihood estimation by default, there are situations where one might prefer to use multiple imputation to handle missing data rather than maximum likelihood estimation (e.g., when incorporating auxiliary variables). The selection of variables is one of the nuances associated…

  6. Multiple Imputation Strategies for Multiple Group Structural Equation Models

    ERIC Educational Resources Information Center

    Enders, Craig K.; Gottschall, Amanda C.

    2011-01-01

    Although structural equation modeling software packages use maximum likelihood estimation by default, there are situations where one might prefer to use multiple imputation to handle missing data rather than maximum likelihood estimation (e.g., when incorporating auxiliary variables). The selection of variables is one of the nuances associated…

  7. Dynamical modelling of coordinated multiple robot systems

    NASA Technical Reports Server (NTRS)

    Hayati, Samad

    1987-01-01

    The state of the art in the modeling of the dynamics of coordinated multiple robot manipulators is summarized and various problems related to this subject are discussed. It is recognized that dynamics modeling is a component used in the design of controllers for multiple cooperating robots. As such, the discussion addresses some problems related to the control of multiple robots. The techniques used to date in the modeling of closed kinematic chains are summarized. Various efforts made to date for the control of coordinated multiple manipulators is summarized.

  8. Analysis of unstable modes distinguishes mathematical models of flagellar motion

    PubMed Central

    Bayly, P. V.; Wilson, K. S.

    2015-01-01

    The mechanisms underlying the coordinated beating of cilia and flagella remain incompletely understood despite the fundamental importance of these organelles. The axoneme (the cytoskeletal structure of cilia and flagella) consists of microtubule doublets connected by passive and active elements. The motor protein dynein is known to drive active bending, but dynein activity must be regulated to generate oscillatory, propulsive waveforms. Mathematical models of flagellar motion generate quantitative predictions that can be analysed to test hypotheses concerning dynein regulation. One approach has been to seek periodic solutions to the linearized equations of motion. However, models may simultaneously exhibit both periodic and unstable modes. Here, we investigate the emergence and coexistence of unstable and periodic modes in three mathematical models of flagellar motion, each based on a different dynein regulation hypothesis: (i) sliding control; (ii) curvature control and (iii) control by interdoublet separation (the ‘geometric clutch’ (GC)). The unstable modes predicted by each model are used to critically evaluate the underlying hypothesis. In particular, models of flagella with ‘sliding-controlled’ dynein activity admit unstable modes with non-propulsive, retrograde (tip-to-base) propagation, sometimes at the same parameter values that lead to periodic, propulsive modes. In the presence of these retrograde unstable modes, stable or periodic modes have little influence. In contrast, unstable modes of the GC model exhibit switching at the base and propulsive base-to-tip propagation. PMID:25833248

  9. Moving vehicles segmentation based on Gaussian motion model

    NASA Astrophysics Data System (ADS)

    Zhang, Wei; Fang, Xiang Z.; Lin, Wei Y.

    2005-07-01

    Moving objects segmentation is a challenge in computer vision. This paper focuses on the segmentation of moving vehicles in dynamic scene. We analyses the psychology of human vision and present a framework for segmenting moving vehicles in the highway. The proposed framework consists of two parts. Firstly, we propose an adaptive background update method in which the background is updated according to the change of illumination conditions and thus can adapt to the change of illumination sensitively. Secondly, we construct a Gaussian motion model to segment moving vehicles, in which the motion vectors of the moving pixels are modeled as a Gaussian model and an on-line EM algorithm is used to update the model. The Gaussian distribution of the adaptive model is elevated to determine which moving vectors result from moving vehicles and which from other moving objects such as waving trees. Finally, the pixels with motion vector result from the moving vehicles are segmented. Experimental results of several typical scenes show that the proposed model can detect the moving vehicles correctly and is immune from influence of the moving objects caused by the waving trees and the vibration of camera.

  10. Accuracy and precision of smartphone applications and commercially available motion sensors in multiple sclerosis.

    PubMed

    Balto, Julia M; Kinnett-Hopkins, Dominique L; Motl, Robert W

    2016-01-01

    There is increased interest in the application of smartphone applications and wearable motion sensors among multiple sclerosis (MS) patients. This study examined the accuracy and precision of common smartphone applications and motion sensors for measuring steps taken by MS patients while walking on a treadmill. Forty-five MS patients (Expanded Disability Status Scale (EDSS) = 1.0-5.0) underwent two 500-step walking trials at comfortable walking speed on a treadmill. Participants wore five motion sensors: the Digi-Walker SW-200 pedometer (Yamax), the UP2 and UP Move (Jawbone), and the Flex and One (Fitbit). The smartphone applications were Health (Apple), Health Mate (Withings), and Moves (ProtoGeo Oy). The Fitbit One had the best absolute (mean = 490.6 steps, 95% confidence interval (CI) = 485.6-495.5 steps) and relative accuracy (1.9% error), and absolute (SD = 16.4) and relative precision (coefficient of variation (CV) = 0.0), for the first 500-step walking trial; this was repeated with the second trial. Relative accuracy was correlated with slower walking speed for the first (rs = -.53) and second (rs = -.53) trials. The results suggest that the waist-worn Fitbit One is the most precise and accurate sensor for measuring steps when walking on a treadmill, but future research is needed (testing the device across a broader range of disability, at different speeds, and in real-life walking conditions) before inclusion in clinical research and practice with MS patients.

  11. Accuracy and precision of smartphone applications and commercially available motion sensors in multiple sclerosis

    PubMed Central

    Balto, Julia M; Kinnett-Hopkins, Dominique L

    2016-01-01

    Background There is increased interest in the application of smartphone applications and wearable motion sensors among multiple sclerosis (MS) patients. Objective This study examined the accuracy and precision of common smartphone applications and motion sensors for measuring steps taken by MS patients while walking on a treadmill. Methods Forty-five MS patients (Expanded Disability Status Scale (EDSS) = 1.0–5.0) underwent two 500-step walking trials at comfortable walking speed on a treadmill. Participants wore five motion sensors: the Digi-Walker SW-200 pedometer (Yamax), the UP2 and UP Move (Jawbone), and the Flex and One (Fitbit). The smartphone applications were Health (Apple), Health Mate (Withings), and Moves (ProtoGeo Oy). Results The Fitbit One had the best absolute (mean = 490.6 steps, 95% confidence interval (CI) = 485.6–495.5 steps) and relative accuracy (1.9% error), and absolute (SD = 16.4) and relative precision (coefficient of variation (CV) = 0.0), for the first 500-step walking trial; this was repeated with the second trial. Relative accuracy was correlated with slower walking speed for the first (rs = −.53) and second (rs = −.53) trials. Conclusion The results suggest that the waist-worn Fitbit One is the most precise and accurate sensor for measuring steps when walking on a treadmill, but future research is needed (testing the device across a broader range of disability, at different speeds, and in real-life walking conditions) before inclusion in clinical research and practice with MS patients. PMID:28607720

  12. Two vortex-blob regularization models for vortex sheet motion

    NASA Astrophysics Data System (ADS)

    Sohn, Sung-Ik

    2014-04-01

    Evolving vortex sheets generally form singularities in finite time. The vortex blob model is an approach to regularize the vortex sheet motion and evolve past singularity formation. In this paper, we thoroughly compare two such regularizations: the Krasny-type model and the Beale-Majda model. It is found from a linear stability analysis that both models have exponentially decaying growth rates for high wavenumbers, but the Beale-Majda model has a faster decaying rate than the Krasny model. The Beale-Majda model thus gives a stronger regularization to the solution. We apply the blob models to the two example problems: a periodic vortex sheet and an elliptically loaded wing. The numerical results show that the solutions of the two models are similar in large and small scales, but are fairly different in intermediate scales. The sheet of the Beale-Majda model has more spiral turns than the Krasny-type model for the same value of the regularization parameter δ. We give numerical evidences that the solutions of the two models agree for an increasing amount of spiral turns and tend to converge to the same limit as δ is decreased. The inner spiral turns of the blob models behave differently with the outer turns and satisfy a self-similar form. We also examine irregular motions of the sheet at late times and find that the irregular motions shrink as δ is decreased. This fact suggests a convergence of the blob solution to the weak solution of infinite regular spiral turns.

  13. Developments in Ground-Motion Modeling in Eastern North America

    NASA Astrophysics Data System (ADS)

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

    2012-12-01

    Recent well-recorded earthquakes in Eastern North America (ENA) have led us to re-evaluate concepts that have been "standard fare" in the development of ground-motion prediction equations (GMPEs) for ENA for decades, including all published GMPEs that are used in current practice (e.g. Atkinson and Boore, 2011, 2006, 1995; Pezeshk et al., 2011; Campbell, 2003; Toro et al., 1997, etc.). Assumptions common to all ENA GMPEs that may not be true include the following. (1) Typical ENA stress drops, in the context of a Brune model representation of the source spectrum, are in the range of 150-300 bars, with the exception of occasional high-stress events like the 1988 Saguenay earthquake. (2) Attenuation of ground motions can be modeled with a frequency-independent geometric spreading function, either bilinear or trilinear in shape (e.g. Street and Turcotte, 1975; Herrmann and Kijko, 1983; Atkinson and Mereu, 1992; Atkinson, 2004; Boatwright and Seekins, 2011), and an associated frequency-dependent anelastic attenuation term related to the regional Quality factor. The use of a bilinear or trilinear form models the transition from geometric spreading of body waves at close distances to slower surface-wave-type spreading at regional distances. We use ground-motion recordings from recent ENA events to re-examine these basic tenets of GMPE development, in light of constraints on the problem provided at low frequencies by seismic moment, and at high frequencies by stresses inferred from Empirical Greens Function (EGF) analysis. We find strong evidence, in both ground-motion data and from the constraints, that geometric attenuation may be frequency dependent. Moreover, EGF stress drops may be very high (>500 bars) - but they do not lead to particularly large high-frequency ground motions, at least at distances for which we have observations. More complex models of ENA source and attenuation processes appear to be required in order to reconcile our growing ground-motion database

  14. Asynchronous partial contact motion due to internal resonance in multiple degree-of-freedom rotordynamics.

    PubMed

    Shaw, A D; Champneys, A R; Friswell, M I

    2016-08-01

    Sudden onset of violent chattering or whirling rotor-stator contact motion in rotational machines can cause significant damage in many industrial applications. It is shown that internal resonance can lead to the onset of bouncing-type partial contact motion away from primary resonances. These partial contact limit cycles can involve any two modes of an arbitrarily high degree-of-freedom system, and can be seen as an extension of a synchronization condition previously reported for a single disc system. The synchronization formula predicts multiple drivespeeds, corresponding to different forms of mode-locked bouncing orbits. These results are backed up by a brute-force bifurcation analysis which reveals numerical existence of the corresponding family of bouncing orbits at supercritical drivespeeds, provided the damping is sufficiently low. The numerics reveal many overlapping families of solutions, which leads to significant multi-stability of the response at given drive speeds. Further, secondary bifurcations can also occur within each family, altering the nature of the response and ultimately leading to chaos. It is illustrated how stiffness and damping of the stator have a large effect on the number and nature of the partial contact solutions, illustrating the extreme sensitivity that would be observed in practice.

  15. Asynchronous partial contact motion due to internal resonance in multiple degree-of-freedom rotordynamics

    NASA Astrophysics Data System (ADS)

    Shaw, A. D.; Champneys, A. R.; Friswell, M. I.

    2016-08-01

    Sudden onset of violent chattering or whirling rotor-stator contact motion in rotational machines can cause significant damage in many industrial applications. It is shown that internal resonance can lead to the onset of bouncing-type partial contact motion away from primary resonances. These partial contact limit cycles can involve any two modes of an arbitrarily high degree-of-freedom system, and can be seen as an extension of a synchronization condition previously reported for a single disc system. The synchronization formula predicts multiple drivespeeds, corresponding to different forms of mode-locked bouncing orbits. These results are backed up by a brute-force bifurcation analysis which reveals numerical existence of the corresponding family of bouncing orbits at supercritical drivespeeds, provided the damping is sufficiently low. The numerics reveal many overlapping families of solutions, which leads to significant multi-stability of the response at given drive speeds. Further, secondary bifurcations can also occur within each family, altering the nature of the response and ultimately leading to chaos. It is illustrated how stiffness and damping of the stator have a large effect on the number and nature of the partial contact solutions, illustrating the extreme sensitivity that would be observed in practice.

  16. Asynchronous partial contact motion due to internal resonance in multiple degree-of-freedom rotordynamics

    PubMed Central

    Champneys, A. R.; Friswell, M. I.

    2016-01-01

    Sudden onset of violent chattering or whirling rotor–stator contact motion in rotational machines can cause significant damage in many industrial applications. It is shown that internal resonance can lead to the onset of bouncing-type partial contact motion away from primary resonances. These partial contact limit cycles can involve any two modes of an arbitrarily high degree-of-freedom system, and can be seen as an extension of a synchronization condition previously reported for a single disc system. The synchronization formula predicts multiple drivespeeds, corresponding to different forms of mode-locked bouncing orbits. These results are backed up by a brute-force bifurcation analysis which reveals numerical existence of the corresponding family of bouncing orbits at supercritical drivespeeds, provided the damping is sufficiently low. The numerics reveal many overlapping families of solutions, which leads to significant multi-stability of the response at given drive speeds. Further, secondary bifurcations can also occur within each family, altering the nature of the response and ultimately leading to chaos. It is illustrated how stiffness and damping of the stator have a large effect on the number and nature of the partial contact solutions, illustrating the extreme sensitivity that would be observed in practice. PMID:27616927

  17. Computational model for amoeboid motion: Coupling membrane and cytosol dynamics.

    PubMed

    Moure, Adrian; Gomez, Hector

    2016-10-01

    A distinguishing feature of amoeboid motion is that the migrating cell undergoes large deformations, caused by the emergence and retraction of actin-rich protrusions, called pseudopods. Here, we propose a cell motility model that represents pseudopod dynamics, as well as its interaction with membrane signaling molecules. The model accounts for internal and external forces, such as protrusion, contraction, adhesion, surface tension, or those arising from cell-obstacle contacts. By coupling the membrane and cytosol interactions we are able to reproduce a realistic picture of amoeboid motion. The model results are in quantitative agreement with experiments and show how cells may take advantage of the geometry of their microenvironment to migrate more efficiently.

  18. Computational model for amoeboid motion: Coupling membrane and cytosol dynamics

    NASA Astrophysics Data System (ADS)

    Moure, Adrian; Gomez, Hector

    2016-10-01

    A distinguishing feature of amoeboid motion is that the migrating cell undergoes large deformations, caused by the emergence and retraction of actin-rich protrusions, called pseudopods. Here, we propose a cell motility model that represents pseudopod dynamics, as well as its interaction with membrane signaling molecules. The model accounts for internal and external forces, such as protrusion, contraction, adhesion, surface tension, or those arising from cell-obstacle contacts. By coupling the membrane and cytosol interactions we are able to reproduce a realistic picture of amoeboid motion. The model results are in quantitative agreement with experiments and show how cells may take advantage of the geometry of their microenvironment to migrate more efficiently.

  19. Multiple brain networks for visual self-recognition with different sensitivity for motion and body part.

    PubMed

    Sugiura, Motoaki; Sassa, Yuko; Jeong, Hyeonjeong; Miura, Naoki; Akitsuki, Yuko; Horie, Kaoru; Sato, Shigeru; Kawashima, Ryuta

    2006-10-01

    Multiple brain networks may support visual self-recognition. It has been hypothesized that the left ventral occipito-temporal cortex processes one's own face as a symbol, and the right parieto-frontal network processes self-image in association with motion-action contingency. Using functional magnetic resonance imaging, we first tested these hypotheses based on the prediction that these networks preferentially respond to a static self-face and to moving one's whole body, respectively. Brain activation specifically related to self-image during familiarity judgment was compared across four stimulus conditions comprising a two factorial design: factor Motion contrasted picture (Picture) and movie (Movie), and factor Body part a face (Face) and whole body (Body). Second, we attempted to segregate self-specific networks using a principal component analysis (PCA), assuming an independent pattern of inter-subject variability in activation over the four stimulus conditions in each network. The bilateral ventral occipito-temporal and the right parietal and frontal cortices exhibited self-specific activation. The left ventral occipito-temporal cortex exhibited greater self-specific activation for Face than for Body, in Picture, consistent with the prediction for this region. The activation profiles of the right parietal and frontal cortices did not show preference for Movie Body predicted by the assumed roles of these regions. The PCA extracted two cortical networks, one with its peaks in the right posterior, and another in frontal cortices; their possible roles in visuo-spatial and conceptual self-representations, respectively, were suggested by previous findings. The results thus supported and provided evidence of multiple brain networks for visual self-recognition.

  20. Innovative modeling of Tuned Liquid Column Damper motion

    NASA Astrophysics Data System (ADS)

    Di Matteo, A.; Lo Iacono, F.; Navarra, G.; Pirrotta, A.

    2015-06-01

    In this paper a new model for the liquid motion within a Tuned Liquid Column Damper (TLCD) device is developed, based on the mathematical tool of fractional calculus. Although the increasing use of these devices for structural vibration control, it is shown that existing model does not always lead to accurate prediction of the liquid motion. A better model is then needed for accurate simulation of the behavior of TLCD systems. As regards, it has been demonstrated how correctly including the first linear liquid sloshing mode, through the equivalent mechanical analogy well established in literature, produces numerical results that highly match the corresponding experimental ones. Since the apparent effect of sloshing is the deviation of the natural frequency from the theoretical one, the authors propose a fractional differential equation of motion. The latter choice is supported by the fact that the introduction a fractional derivative of order α alters simultaneously both the resonant frequency and the degree of damping of the system. It will be shown, through an extensive experimental analysis, how the proposed model accurately describes liquid surface displacements.

  1. A discrete impulsive model for random heating and Brownian motion

    NASA Astrophysics Data System (ADS)

    Ramshaw, John D.

    2010-01-01

    The energy of a mechanical system subjected to a random force with zero mean increases irreversibly and diverges with time in the absence of friction or dissipation. This random heating effect is usually encountered in phenomenological theories formulated in terms of stochastic differential equations, the epitome of which is the Langevin equation of Brownian motion. We discuss a simple discrete impulsive model that captures the essence of random heating and Brownian motion. The model may be regarded as a discrete analog of the Langevin equation, although it is developed ab initio. Its analysis requires only simple algebraic manipulations and elementary averaging concepts, but no stochastic differential equations (or even calculus). The irreversibility in the model is shown to be a consequence of a natural causal stochastic condition that is closely analogous to Boltzmann's molecular chaos hypothesis in the kinetic theory of gases. The model provides a simple introduction to several ostensibly more advanced topics, including random heating, molecular chaos, irreversibility, Brownian motion, the Langevin equation, and fluctuation-dissipation theorems.

  2. Manifold learning for object tracking with multiple nonlinear models.

    PubMed

    Nascimento, Jacinto C; Silva, Jorge G; Marques, Jorge S; Lemos, Joao M

    2014-04-01

    This paper presents a novel manifold learning algorithm for high-dimensional data sets. The scope of the application focuses on the problem of motion tracking in video sequences. The framework presented is twofold. First, it is assumed that the samples are time ordered, providing valuable information that is not presented in the current methodologies. Second, the manifold topology comprises multiple charts, which contrasts to the most current methods that assume one single chart, being overly restrictive. The proposed algorithm, Gaussian process multiple local models (GP-MLM), can deal with arbitrary manifold topology by decomposing the manifold into multiple local models that are probabilistic combined using Gaussian process regression. In addition, the paper presents a multiple filter architecture where standard filtering techniques are integrated within the GP-MLM. The proposed approach exhibits comparable performance of state-of-the-art trackers, namely multiple model data association and deep belief networks, and compares favorably with Gaussian process latent variable models. Extensive experiments are presented using real video data, including a publicly available database of lip sequences and left ventricle ultrasound images, in which the GP-MLM achieves state of the art results.

  3. A New Absolute Plate Motion Model for Africa

    NASA Astrophysics Data System (ADS)

    Maher, S. M.; Wessel, P.; Müller, D.; Harada, Y.

    2013-12-01

    The India-Eurasia collision, a change in relative plate motion between Australia and Antarctica, and the coeval ages of the Hawaiian Emperor Bend (HEB) and Louisville Bend of ~Chron 22-21 all provide convincing evidence of a global tectonic plate reorganization at ~50 Ma. Yet if it were a truly global event, then there should be a contemporaneous change in Africa absolute plate motion (APM) reflected by physical evidence somewhere on the Africa plate. This evidence might be visible in the Reunion-Mascarene bend, which exhibits many HEB-like features such as a large angular change close to ~50 Ma. Recently, the Reunion hotpot trail has been interpreted as a continental feature with incidental hotspot volcanism. Here we propose the alternative hypothesis that the northern portion of the chain between Saya de Malha and the Seychelles (Mascarene Plateau) formed as the Reunion hotspot was situated on the Carlsberg Ridge, contemporaneously forming the Chagos-Laccadive Ridge on the India plate. We have created a 4-stage model that explores how a simple APM model fitting the Mascarene Plateau can also satisfy the age progressions and geometry of other hotspot trails on the Africa plate. This type of model could explain the apparent bifurcation of the Tristan hotspot chain, the age reversals seen along the Walvis Ridge and the diffuse nature of the St. Helena chain. To test this hypothesis we have made a new African APM model that goes back to ~80 Ma using a modified version of the Hybrid Polygonal Finite Rotation Method. This method uses seamount chains and their associated hotspots as geometric constraints for the model, and seamount age dates to determine its motion through time. The positions of the hotspots can be moved to get the best fit for the model and to explore the possibility that the ~50 Ma bend in the Reunion-Mascarene chain reflects Africa plate motion. We will examine how well this model can predict the key features reflecting Africa plate motion and

  4. Quantum Brownian motion model for the stock market

    NASA Astrophysics Data System (ADS)

    Meng, Xiangyi; Zhang, Jian-Wei; Guo, Hong

    2016-06-01

    It is believed by the majority today that the efficient market hypothesis is imperfect because of market irrationality. Using the physical concepts and mathematical structures of quantum mechanics, we construct an econophysical framework for the stock market, based on which we analogously map massive numbers of single stocks into a reservoir consisting of many quantum harmonic oscillators and their stock index into a typical quantum open system-a quantum Brownian particle. In particular, the irrationality of stock transactions is quantitatively considered as the Planck constant within Heisenberg's uncertainty relationship of quantum mechanics in an analogous manner. We analyze real stock data of Shanghai Stock Exchange of China and investigate fat-tail phenomena and non-Markovian behaviors of the stock index with the assistance of the quantum Brownian motion model, thereby interpreting and studying the limitations of the classical Brownian motion model for the efficient market hypothesis from a new perspective of quantum open system dynamics.

  5. Model-Based Motion Estimation and Its Application to Restoration and Interpolation of Motion Pictures.

    DTIC Science & Technology

    1987-06-01

    A common example of this problem occurs when motion picture films are shown on a conventional NTSC television system. The motion picture industry...second, or 30 frames per second. In order to show a motion picture film on an NTSC television system, temporal interpolation is necessary. The technique...Application to Restoration and Interpolation of Motion Pictures ", Dennis Michael Martinez Technical Report No. 530 June 1987 DTIO aELECTE SEp 2 3N DWM I

  6. Autonomous Coordination and Online Motion Modeling for Mobile Robots

    DTIC Science & Technology

    2007-09-01

    number of robots. The second goal of this work is to demonstrate a method by which a robot can automatically determine how it is moving...The second goal of this work is to demonstrate a method by which a robot can automatically determine how it is moving. Experiments demonstrate the...to introduce a method for automatically learning a robot’s motion model. The algorithm will be employed on real mobile robots so as to ensure the

  7. Elements of an improved model of debris-flow motion

    USGS Publications Warehouse

    Iverson, R.M.

    2009-01-01

    A new depth-averaged model of debris-flow motion describes simultaneous evolution of flow velocity and depth, solid and fluid volume fractions, and pore-fluid pressure. Non-hydrostatic pore-fluid pressure is produced by dilatancy, a state-dependent property that links the depth-averaged shear rate and volumetric strain rate of the granular phase. Pore-pressure changes caused by shearing allow the model to exhibit rate-dependent flow resistance, despite the fact that the basal shear traction involves only rate-independent Coulomb friction. An analytical solution of simplified model equations shows that the onset of downslope motion can be accelerated or retarded by pore-pressure change, contingent on whether dilatancy is positive or negative. A different analytical solution shows that such effects will likely be muted if downslope motion continues long enough, because dilatancy then evolves toward zero, and volume fractions and pore pressure concurrently evolve toward steady states. ?? 2009 American Institute of Physics.

  8. Multiple lesion track structure model

    NASA Technical Reports Server (NTRS)

    Wilson, John W.; Cucinotta, Francis A.; Shinn, Judy L.

    1992-01-01

    A multilesion cell kinetic model is derived, and radiation kinetic coefficients are related to the Katz track structure model. The repair-related coefficients are determined from the delayed plating experiments of Yang et al. for the C3H10T1/2 cell system. The model agrees well with the x ray and heavy ion experiments of Yang et al. for the immediate plating, delaying plating, and fractionated exposure protocols employed by Yang. A study is made of the effects of target fragments in energetic proton exposures and of the repair-deficient target-fragment-induced lesions.

  9. Modelling the effect of race surface and racehorse limb parameters on in silico fetlock motion and propensity for injury.

    PubMed

    Symons, J E; Hawkins, D A; Fyhrie, D P; Upadhyaya, S K; Stover, S M

    2017-09-01

    The metacarpophalangeal joint (fetlock) is the most commonly affected site of racehorse injury, with multiple observed pathologies consistent with extreme fetlock dorsiflexion. Race surface mechanics affect musculoskeletal structure loading and injury risk because surface forces applied to the hoof affect limb motions. Race surface mechanics are a function of controllable factors. Thus, race surface design has the potential to reduce the incidence of musculoskeletal injury through modulation of limb motions. However, the relationship between race surface mechanics and racehorse limb motions is unknown. To determine the effect of changing race surface and racehorse limb model parameters on distal limb motions. Sensitivity analysis of in silico fetlock motion to changes in race surface and racehorse limb parameters using a validated, integrated racehorse and race surface computational model. Fetlock motions were determined during gallop stance from simulations on virtual surfaces with differing average vertical stiffness, upper layer (e.g. cushion) depth and linear stiffness, horizontal friction, tendon and ligament mechanics, as well as fetlock position at heel strike. Upper layer depth produced the greatest change in fetlock motion, with lesser depths yielding greater fetlock dorsiflexion. Lesser fetlock changes were observed for changes in lower layer (e.g. base or pad) mechanics (nonlinear), as well as palmar ligament and tendon stiffness. Horizontal friction and fetlock position contributed less than 1° change in fetlock motion. Simulated fetlock motions are specific to one horse's anatomy reflected in the computational model. Anatomical differences among horses may affect the magnitude of limb flexion, but will likely have similar limb motion responses to varied surface mechanics. Race surface parameters affected by maintenance produced greater changes in fetlock motion than other parameters studied. Simulations can provide evidence to inform race surface

  10. Modeling the influence of plate motions on subduction

    NASA Astrophysics Data System (ADS)

    Hillebrand, Bram; Thieulot, Cedric; van den Berg, Arie; Spakman, Wim

    2014-05-01

    Subduction zones are widely studied complex geodynamical systems. Their evolution is influenced by a broad range of parameters such as the age of the plates (both subducting and overriding) as well as their rheology, their nature (oceanic or continental), the presence of a crust and the involved plate motions to name a few. To investigate the importance of these different parameters on the evolution of subduction we have created a series of 2D numerical thermomechanical subduction models. These subduction models are multi-material flow models containing continental and oceanic crusts, a lithosphere and a mantle. We use the sticky air approach to allow for topography build up in the model. In order to model multi-material flow in our Eulerian finite element code of SEPRAN (Segal and Praagman, 2000) we use the well benchmarked level set method (Osher and Sethian, 1988) to track the different materials and their mode of deformation through the model domain. To our knowledge the presented results are the first subduction model results with the level set method. We will present preliminary results of our parametric study focusing mainly on the influence of plate motions on the evolution of subduction. S. Osher and J.A. Sethian. Fronts propagating with curvature-dependent speed: Algorithms based on hamilton-jacobi formulations. JCP 1988 A. Segal and N.P. Praagman. The SEPRAN package. Technical report, 2000 This research is funded by The Netherlands Research Centre for Integrated Solid Earth Science (ISES)

  11. One-degree-of-freedom motion induced by modeled vortex shedding

    NASA Technical Reports Server (NTRS)

    Yates, L. A.; Unal, A.; Szady, M.; Chapman, G. T.

    1989-01-01

    The motion of an elastically supported cylinder forced by a nonlinear, quasi-static, aerodynamic model with the unusual feature of a motion-dependent forcing frequency was studied. Numerical solutions for the motion and the Lyapunov exponents are presented for three forcing amplitudes and two frequencies (1.0 and 1.1 times the Strouhal frequency). Initially, positive Lyapunov exponents occur and the motion can appear chaotic. After thousands of characteristic times, the motion changes to a motion (verified analytically) that is periodic and damped. This periodic, damped motion was not observed experimentally, thus raising questions concerning the modeling.

  12. Polar Motion Constraints on Models of the Fortnightly Tide

    NASA Technical Reports Server (NTRS)

    Ray, Richard D.; Egbert, G. D.; Smith, David E. (Technical Monitor)

    2002-01-01

    Estimates of the near-fortnightly Mf ocean tide from Topex/Poseidon satellite altimetry and from numerical solutions to the shallow water equations agree reasonably well, at least in their basin-scale features. For example, both show that the Pacific Ocean tide lags the Atlantic tide by roughly 30 degrees. There are hints of finer scale agreements in the elevation fields, but noise levels are high. In contrast, estimates of Mf currents are only weakly constrained by the TP data, because high-wavenumber Rossby waves (with intense currents) are associated with relatively small perturbations in surface elevation. As a result, a wide range of Mf current fields are consistent with both the TP data and the hydrodynamic equations within a priori plausible misfit bounds. We find that a useful constraint on the Mf currents is provided by independent estimates of the Earth's polar motion. At the Mf period polar motion shows a weak signal (both prograde and retrograde) which must be almost entirely caused by the ocean tide. We have estimated this signal from the SPACE2000 time series, after applying a broad-band correction for atmospheric angular momentum. Although the polar motion estimates have relatively large uncertainties, they are sufficiently precise to fix optimum data weights in a global ocean inverse model of Mf. These weights control the tradeoff between fitting a prior hydrodynamic model of Mf and fitting the relatively noisy T/P measurements of Mf. The predicted polar motion from the final inverse model agrees remarkably well with the Mf polar motion observations. The preferred model is also consistent with noise levels suggested by island gauges, and it is marginally consistent with differences observed by subsetting the altimetry (to the small extent that this is possible). In turn, this new model of the Mf ocean tide allows the ocean component to be removed from Mf estimates of length of day, thus yielding estimates of complex Love numbers less contaminated by

  13. Polar Motion Constraints on Models of the Fortnightly Tide

    NASA Technical Reports Server (NTRS)

    Ray, Richard D.; Egbert, G. D.; Smith, David E. (Technical Monitor)

    2002-01-01

    Estimates of the near-fortnightly Mf ocean tide from Topex/Poseidon satellite altimetry and from numerical solutions to the shallow water equations agree reasonably well, at least in their basin-scale features. For example, both show that the Pacific Ocean tide lags the Atlantic tide by roughly 30 degrees. There are hints of finer scale agreements in the elevation fields, but noise levels are high. In contrast, estimates of Mf currents are only weakly constrained by the TP data, because high-wavenumber Rossby waves (with intense currents) are associated with relatively small perturbations in surface elevation. As a result, a wide range of Mf current fields are consistent with both the TP data and the hydrodynamic equations within a priori plausible misfit bounds. We find that a useful constraint on the Mf currents is provided by independent estimates of the Earth's polar motion. At the Mf period polar motion shows a weak signal (both prograde and retrograde) which must be almost entirely caused by the ocean tide. We have estimated this signal from the SPACE2000 time series, after applying a broad-band correction for atmospheric angular momentum. Although the polar motion estimates have relatively large uncertainties, they are sufficiently precise to fix optimum data weights in a global ocean inverse model of Mf. These weights control the tradeoff between fitting a prior hydrodynamic model of Mf and fitting the relatively noisy T/P measurements of Mf. The predicted polar motion from the final inverse model agrees remarkably well with the Mf polar motion observations. The preferred model is also consistent with noise levels suggested by island gauges, and it is marginally consistent with differences observed by subsetting the altimetry (to the small extent that this is possible). In turn, this new model of the Mf ocean tide allows the ocean component to be removed from Mf estimates of length of day, thus yielding estimates of complex Love numbers less contaminated by

  14. Trajectory models and reference frames for crustal motion geodesy

    NASA Astrophysics Data System (ADS)

    Bevis, Michael; Brown, Abel

    2014-03-01

    We sketch the evolution of station trajectory models used in crustal motion geodesy over the last several decades, and describe some recent generalizations of these models that allow geodesists and geophysicists to parameterize accelerating patterns of displacement in general, and postseismic transient deformation in particular. Modern trajectory models are composed of three sub-models that represent secular trends, annual oscillations, and instantaneous jumps in coordinate time series. Traditionally the trend model invoked constant station velocity. This can be generalized by assuming that position is a polynomial function of time. The trajectory model can also be augmented as needed, by including one or more logarithmic transients in order to account for typical multi-year patterns of postseismic transient motion. Many geodetic and geophysical research groups are using general classes of trajectory model to characterize their crustal displacement time series, but few if any of them are using these trajectory models to define and realize the terrestrial reference frames (RFs) in which their time series are expressed. We describe a global GPS reanalysis program in which we use two general classes of trajectory model, tuned on a station by station basis. We define the network trajectory model as the set of station trajectory models encompassing every station in the network. We use the network trajectory model from the each global analysis to assign prior position estimates for the next round of GPS data processing. We allow our daily orbital solutions to relax so as to maintain their consistency with the network polyhedron. After several iterations we produce GPS time series expressed in a RF similar to, but not identical with ITRF2008. We find that each iteration produces an improvement in the daily repeatability of our global time series and in the predictive power of our trajectory models.

  15. Lumbar joint torque estimation based on simplified motion measurement using multiple inertial sensors.

    PubMed

    Miyajima, Saori; Tanaka, Takayuki; Imamura, Yumeko; Kusaka, Takashi

    2015-01-01

    We estimate lumbar torque based on motion measurement using only three inertial sensors. First, human motion is measured by a 6-axis motion tracking device that combines a 3-axis accelerometer and a 3-axis gyroscope placed on the shank, thigh, and back. Next, the lumbar joint torque during the motion is estimated by kinematic musculoskeletal simulation. The conventional method for estimating joint torque uses full body motion data measured by an optical motion capture system. However, in this research, joint torque is estimated by using only three link angles of the body, thigh, and shank. The utility of our method was verified by experiments. We measured motion of bendung knee and waist simultaneously. As the result, we were able to estimate the lumbar joint torque from measured motion.

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

    SciTech Connect

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

    2013-10-01

    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{sub 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{sub max} up to 25% and reduce the diameter of the 50% SUV{sub 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.

  17. Enhanced performance for the interacting multiple model estimator with integrated multiple filters

    NASA Astrophysics Data System (ADS)

    Sabordo, Madeleine G.; Aboutanios, Elias

    2015-05-01

    In this paper, we propose a new approach to target visibility for the Interacting Multiple Model (IMM) algorithm. We introduce the IMM Integrated Multiple Filters (IMF) to selectively engage a suitable filter appropriate for gated clutter density at each time step and investigate five model sets that model the dynamic motion of a manoeuvring target. The model sets are incorporated into the IMM-IMF tracker to estimate the behaviour of the target. We employ the Dynamic Error Spectrum (DES) to assess the effectiveness of the tracker with target visibility concept incorporated and to compare the performance of the model sets in enhancing tracking performance. Results show that the new version of target visibility significantly improves the performance of the tracker. Simulation results also demonstrate that the 2CV-CA-2CT model set proves to be the most robust at the cost of computational resource. The CV-CA model is the fastest tracker. However, it is the least robust in terms of performance. These results assist decision makers and researchers in choosing appropriate models for IMMtrackers. Augmenting the capability of the tracker improves the ability of the platform to identify possible threats and consequently, enhance situational awareness.

  18. Near-wall aerodynamics of idealized model foot motion

    NASA Astrophysics Data System (ADS)

    Kubota, Yoshi; Hall, Joseph; Higuchi, Hiroshi; Sheth, Ritesh; Glauser, Mark; Khalifa, Ezzat

    2006-11-01

    The air quality is affected by amounts and types of contaminant particles suspended in the air. The particulate matter reaches the respiratory system in an indoor environment by fist becoming detached, resupended and then entrained in the human micro-environment. The resuspension phenomena from the floor occur through either a ballistic mechanism, where kinetic energy is transferred to dust particles through direct contact, or an aerodynamic mechanism, where dust particles are resuspended by the flow generated by the body. In this study we focus on the aerodynamic resuspension of particles caused by walking. The foot motion is idealized and is either towards or away from a floor. A circular disk and an elongated plate having the equivalent area to that of a human foot are used. The foot motion is driven vertically by a linear servo motor that controls the velocity, acceleration, stroke and deceleration. The model velocity is based on the real foot motion. In addition to flow visualization, flowfield measurements were conducted with PIV. In the downstroke, results show a vortex impacting the wall creating the strong wall jet. In upstroke, the vortex generated behind the idealized foot exhibits the large magnitude of velocity. Experiment is continuing with a model more closely to simulating shoe geometry as well as incorporating the real foot kinetics. The results will be compared with the numerical simulation and analytical results.

  19. Fractional Lévy stable motion can model subdiffusive dynamics

    NASA Astrophysics Data System (ADS)

    Burnecki, Krzysztof; Weron, Aleksander

    2010-08-01

    We show in this paper that the sample (time average) mean-squared displacement (MSD) of the fractional Lévy α -stable motion behaves very differently from the corresponding ensemble average (second moment). While the ensemble average MSD diverges for α<2 , the sample MSD may exhibit either subdiffusion, normal diffusion, or superdiffusion. Thus, H -self-similar Lévy stable processes can model either a subdiffusive, diffusive or superdiffusive dynamics in the sense of sample MSD. We show that the character of the process is controlled by a sign of the memory parameter d=H-1/α . We also introduce a sample p -variation dynamics test which allows to distinguish between two models of subdiffusive dynamics. Finally, we illustrate a subdiffusive behavior of the fractional Lévy stable motion on biological data describing the motion of individual fluorescently labeled mRNA molecules inside live E. coli cells, but it may concern many other fields of contemporary experimental physics.

  20. Modelling atmospheric turbulence for a motion-based simulator

    NASA Technical Reports Server (NTRS)

    Jacobson, I. D.; Joshi, D.

    1975-01-01

    The background information in establishing several proposed atmospheric turbulence models for use on motion based aircraft simulators was documented. A specific model was proposed which, in addition to varying turbulence intensity (rms velocity), varies the atmospheric turbulence scale length to achieve compatibility with real atmospheric turbulence. With a suitable combination of scale length and intensity distribution, the model will simulate various atmospheric conditions characterized by altitude, stability, and terrain. The model is mechanized to be included in a flight simulator experiment in order to determine to what extent the pilots are sensitive to changes in atmospheric conditions and the realism of the model. The following topics were covered: literature survey, presently used techniques, proposed model, and simulation details.

  1. Fractional-order variational optical flow model for motion estimation.

    PubMed

    Chen, Dali; Sheng, Hu; Chen, YangQuan; Xue, Dingyü

    2013-05-13

    A new class of fractional-order variational optical flow models, which generalizes the differential of optical flow from integer order to fractional order, is proposed for motion estimation in this paper. The corresponding Euler-Lagrange equations are derived by solving a typical fractional variational problem, and the numerical implementation based on the Grünwald-Letnikov fractional derivative definition is proposed to solve these complicated fractional partial differential equations. Theoretical analysis reveals that the proposed fractional-order variational optical flow model is the generalization of the typical Horn and Schunck (first-order) variational optical flow model and the second-order variational optical flow model, which provides a new idea for us to study the optical flow model and has an important theoretical implication in optical flow model research. The experiments demonstrate the validity of the generalization of differential order.

  2. Mobility and dynamics modeling for unmanned ground vehicle motion planning

    NASA Astrophysics Data System (ADS)

    Witus, Gary

    1999-07-01

    This paper presents an approach to modeling unmanned ground vehicle (UGV) mobility performance and vehicle dynamics for evaluating the feasibility and cost of alternative motion plans. Feasibility constraints include power, traction, and roll stability limits. Sensor stabilization performance is considered in a system-level constraint requiring that the obstacle detection distance exceed the stopping distance. Mission time and power requirements are inputs to a multi- attribute cost function for planning under uncertainty. The modeling approach combines a theoretical first-principles mathematical model with an empirical knowledge-based model. The first-principles model predicts performance in an idealized deterministic environment. On-board vehicle dynamics control, for dynamic load balancing and traction management, legitimize some of the simplifying assumptions. The knowledge- based model uses historical relationships to predict the mean and variance of total system performance accounting for the contributions of unplanned reactive behaviors, local terrain variations, and vehicle response transients.

  3. Motion of the heliospheric termination shock - A gas dynamic model

    NASA Technical Reports Server (NTRS)

    Barnes, Aaron

    1993-01-01

    A simple quantitative model is presented for the heliospheric termination shock's anticipated movement in response to upstream solar wind condition variations, under the assumption that the termination shock is initially a strong gasdynamic shock that is at rest relative to the sun, and that there is a discontinuous increase or decrease in the dynamical pressure upstream of the shock. The model suggests that the termination shock is constantly in motion, and that the mean position of the shock lies near the mean equilibrium position which corresponds to the balance between the mean solar wind dynamical pressure and the mean interstellar pressure.

  4. Fractional Levy stable motion for modeling speckle image

    NASA Astrophysics Data System (ADS)

    Li, Xutao; Jin, Lianwen; Peng, Fuyuan; Zhu, Aiping

    2008-03-01

    Recently, stable processes have turned out to be good models for many impulsive signals and noises. The speckle noise in underwater, SAR and the cosmic background images has been proved to have heavy tails distributions and Long Rang Dependent (LRD) structures. In this paper, the Fractional Levy Stable Motion (FLSM) is introduced to model such speckle phenomenon. The synthesis approaches employing Random Midpoint Displacement (RMD) and FFT technology are presented to generate such speckle image respectively. Then, we introduce Wavelet Analysis (WA) method to estimate the LRD exponent H and propose two new technologies in estimation H parameter by Fractional Low Order Moment (FLOM) and Fractional Spectrum (FS) respectively.

  5. Motion of the heliospheric termination shock - A gas dynamic model

    NASA Technical Reports Server (NTRS)

    Barnes, Aaron

    1993-01-01

    A simple quantitative model is presented for the heliospheric termination shock's anticipated movement in response to upstream solar wind condition variations, under the assumption that the termination shock is initially a strong gasdynamic shock that is at rest relative to the sun, and that there is a discontinuous increase or decrease in the dynamical pressure upstream of the shock. The model suggests that the termination shock is constantly in motion, and that the mean position of the shock lies near the mean equilibrium position which corresponds to the balance between the mean solar wind dynamical pressure and the mean interstellar pressure.

  6. Multiplicity Control in Structural Equation Modeling

    ERIC Educational Resources Information Center

    Cribbie, Robert A.

    2007-01-01

    Researchers conducting structural equation modeling analyses rarely, if ever, control for the inflated probability of Type I errors when evaluating the statistical significance of multiple parameters in a model. In this study, the Type I error control, power and true model rates of famsilywise and false discovery rate controlling procedures were…

  7. Analysis of nitroxide spin label motion in a protein protein complex using multiple frequency EPR spectroscopy

    NASA Astrophysics Data System (ADS)

    White, G. F.; Ottignon, L.; Georgiou, T.; Kleanthous, C.; Moore, G. R.; Thomson, A. J.; Oganesyan, V. S.

    2007-04-01

    X- and W-band EPR spectra, at room and low temperatures, are reported for nitroxide spin labels attached to cysteine residues selectively introduced into two proteins, the DNase domain of colicin-E9 and its immunity protein, Im9. The dynamics of each site of attachment on the individual proteins and in the tight DNase-Im9 complex have been analysed by computer simulations of the spectra using a model of Brownian dynamics trajectories for the spin label and protein. Ordering potentials have been introduced to describe mobility of labels restricted by the protein domain. Label mobility varies with position from completely immobilised, to motionally restricted and to freely rotating. Bi-modal dynamics of the spin label have been observed for several sites. We show that W-band spectra are particularly useful for detection of anisotropy of spin label motion. On complex formation significant changes are observed in the dynamics of labels at the binding interface region. This work reveals multi-frequency EPR as a sensitive and valuable tool for detecting conformational changes in protein structure and dynamics especially in protein-protein complexes.

  8. Diffusion in different models of active Brownian motion

    NASA Astrophysics Data System (ADS)

    Lindner, B.; Nicola, E. M.

    2008-04-01

    Active Brownian particles (ABP) have served as phenomenological models of self-propelled motion in biology. We study the effective diffusion coefficient of two one-dimensional ABP models (simplified depot model and Rayleigh-Helmholtz model) differing in their nonlinear friction functions. Depending on the choice of the friction function the diffusion coefficient does or does not attain a minimum as a function of noise intensity. We furthermore discuss the case of an additional bias breaking the left-right symmetry of the system. We show that this bias induces a drift and that it generally reduces the diffusion coefficient. For a finite range of values of the bias, both models can exhibit a maximum in the diffusion coefficient vs. noise intensity.

  9. Changes in Upper Extremity Range of Motion and Efficiency in Multiple Sclerosis Patients Due to Water Activity.

    ERIC Educational Resources Information Center

    Duthie, Pamela Rae

    To determine the effects of water exercise on the movements of multiple sclerosis patients, this study utilized tests to determine changes in the linear range of motion of the shoulder, elbow, and wrist after a 45-minute period of water activities and to determine if the movement became more effective. The test used was an overhead throw with a…

  10. Modeling the Nonlinear Motion of the Rat Central Airways.

    PubMed

    Ibrahim, G; Rona, A; Hainsworth, S V

    2016-01-01

    Advances in volumetric medical imaging techniques allowed the subject-specific modeling of the bronchial flow through the first few generations of the central airways using computational fluid dynamics (CFD). However, a reliable CFD prediction of the bronchial flow requires modeling of the inhomogeneous deformation of the central airways during breathing. This paper addresses this issue by introducing two models of the central airways motion. The first model utilizes a node-to-node mapping between the discretized geometries of the central airways generated from a number of successive computed tomography (CT) images acquired dynamically (without breath hold) over the breathing cycle of two Sprague-Dawley rats. The second model uses a node-to-node mapping between only two discretized airway geometries generated from the CT images acquired at end-exhale and at end-inhale along with the ventilator measurement of the lung volume change. The advantage of this second model is that it uses just one pair of CT images, which more readily complies with the radiation dosage restrictions for humans. Three-dimensional computer aided design geometries of the central airways generated from the dynamic-CT images were used as benchmarks to validate the output from the two models at sampled time-points over the breathing cycle. The central airway geometries deformed by the first model showed good agreement to the benchmark geometries within a tolerance of 4%. The central airway geometry deformed by the second model better approximated the benchmark geometries than previous approaches that used a linear or harmonic motion model.

  11. Preclinical animal models of multiple myeloma

    PubMed Central

    Lwin, Seint T; Edwards, Claire M; Silbermann, Rebecca

    2016-01-01

    Multiple myeloma is an incurable plasma-cell malignancy characterized by osteolytic bone disease and immunosuppression. Murine models of multiple myeloma and myeloma bone disease are critical tools for an improved understanding of the pathogenesis of the disease and the development of novel therapeutic strategies. This review will cover commonly used immunocompetent and xenograft models of myeloma, describing the advantages and disadvantages of each model system. In addition, this review provides detailed protocols for establishing systemic and local models of myeloma using both murine and human myeloma cell lines. PMID:26909147

  12. Age Dependent Absolute Plate and Plume Motion Modeling

    NASA Astrophysics Data System (ADS)

    Heaton, D. E.; Koppers, A. A. P.

    2015-12-01

    Current absolute plate motion (APM) models from 80 - 0 Ma are constrained by the location of mantle plume related hotspot seamounts, in particular those of the Hawaiian-Emperor and Louisville seamount trails. Originally the 'fixed' hotspot hypothesis was developed to explain past plate motion based on linear age progressive intra-plate volcanism. However, now that 'moving' hotspots are accepted, it is becoming clear that APM models need to be corrected for individual plume motion vectors. For older seamount trails that were active between roughly 50 and 80 Ma the APM models that use 'fixed' hotspots overestimate the measured age progression in those trails, while APM models corrected for 'moving' hotspots underestimate those age progressions. These mismatches are due to both a lack of reliable ages in the older portions of both the Hawaii and Louisville seamount trails and insufficient APM modeling constraints from other seamount trails in the Pacific Basin. Seamounts are difficult to sample and analyze because many are hydrothermally altered and have low potassium concentrations. New 40Ar/39Ar Age results from International Ocean Drilling Project (IODP) Expedition 330 Sites U1372 (n=18), U1375 (n=3), U1376 (n=15) and U1377 (n=7) aid in constraining the oldest end of the Louisville Seamount trail. A significant observation in this study is that the age range recovered in the drill cores match the range of ages that were acquired on dredging cruises at the same seamounts (e.g. Koppers et al., 2011). This is important for determining the inception age of a seamount. The sections recovered from IODP EXP 330 are in-situ volcanoclastic breccia and lava flows. Comparing the seismic interpretations of Louisville guyots (Contreras-Reyes et al., 2010), Holes U1372, U1373 and U1374 penetrated the extrusive and volcanoclastic sections of the seamount. The ages obtained are consistent over stratigraphic intervals >100-450 m thick, providing evidence that these seamounts

  13. Modelling of image-catheter motion for 3-D IVUS.

    PubMed

    Rosales, Misael; Radeva, Petia; Rodriguez-Leor, Oriol; Gil, Debora

    2009-02-01

    Three-dimensional intravascular ultrasound (IVUS) allows to visualize and obtain volumetric measurements of coronary lesions through an exploration of the cross sections and longitudinal views of arteries. However, the visualization and subsequent morpho-geometric measurements in IVUS longitudinal cuts are subject to distortion caused by periodic image/vessel motion around the IVUS catheter. Usually, to overcome the image motion artifact ECG-gating and image-gated approaches are proposed, leading to slowing the pullback acquisition or disregarding part of IVUS data. In this paper, we argue that the image motion is due to 3-D vessel geometry as well as cardiac dynamics, and propose a dynamic model based on the tracking of an elliptical vessel approximation to recover the rigid transformation and align IVUS images without loosing any IVUS data. We report an extensive validation with synthetic simulated data and in vivo IVUS sequences of 30 patients achieving an average reduction of the image artifact of 97% in synthetic data and 79% in real-data. Our study shows that IVUS alignment improves longitudinal analysis of the IVUS data and is a necessary step towards accurate reconstruction and volumetric measurements of 3-D IVUS.

  14. A Pelvic Phantom for Modeling Internal Organ Motions

    SciTech Connect

    Kovacs, Peter; Sebestyen, Zsolt; Farkas, Robert; Bellyei, Szabolcs; Szigeti, Andras; Liposits, Gabor; Hideghety, Katalin; Derczy, Katalin; Mangel, Laszlo

    2011-10-01

    A pelvic phantom was developed for use in testing image-guided radiation therapy (IGRT) and adaptive applications in radiation therapy (ART) with simulating the anterior-posterior internal organ motions during prostate radiotherapy. Measurements could be done with an ionization chamber (IC) in the simulated prostate. The rectum was simulated by air-equivalent material (AEM). The volume superior to the IC placement was considered as the bladder. The extension of AEM volume could be varied. The vertical position of the IC placement could be shifted by {+-}1 cm to simulate the prostate motion parallel to the changes in bladder volume. The reality of the simulation was inspected. Three-millimeter-slice-increment computed tomography (CT) scans were taken for irradiation planning. The structure set was adapted to the phantom from a treated patient. Planning target volume was delineated according to the RTOG 0126 study. IMRT and 3D conformal radiation therapy (3D-CRT) plans were made. Prostate motion and rectum volume changes were simulated in the phantom. IC displacement was corrected by phantom shifting. The delivered dose was measured with IC in 7 cases using intensity-modulated radiation therapy (IMRT) and 3D-CRT fractions, and single square-shaped beams: anteroposterior (AP), posteroanterior (PA), and lateral (LAT). Variations from the calculated doses were slightly below 1% at IMRT and around 1% at 3D-CRT; below 4.5% at square AP beam; up to 9% at square PA beam; and around 0.5% at square LAT beam. Other authors have already shown that by using planning systems and ultrasonic and cone beam CT guidance, correction of organ motions in a real patient during prostate cancer IGRT does not have a significant dosimetric effect. The inspection of our phantom-as described here-ended with similar results. Our team suggested that our model is sufficiently realistic and can be used for IGRT and ART testing.

  15. Motion correction for q-space imaging by multiple interleaved b0 images

    NASA Astrophysics Data System (ADS)

    Muto, Miyu; Du, Weiwei; Fukuzawa, Masayuki; Sakai, Koji; Tazoe, Jun; Ikeno, Hiroyasu; Yamada, Kei

    2016-03-01

    Subject motion in a large number of diffusion weighted images (DWIs) for q-space analysis was detected and corrected by using a simple protocol to add multiple interleaved b0 images between each DWI set and at the very end of data acquisition. The realignment matrix was determined from each b0 image with respect to the first b0 image and the matrix was used to realign not only the b0 image itself but also its subsequent DWI set. Degree of improvement in q-space analysis was estimated by calculating total residual sum of squares (RSS) in bi-exponential curve fitting process and also on the fractional anisotropy (FA) of zero displacement (ZDP). The large RSS regions were considerably diminished by realignment at the edges between cerebral gyri and sulci and at the ventricle boundaries in the original images. The large RSS regions around basal ganglia and near the ventricles were kept even by realignment but considerably suppressed with the averaged b0 image for decay-curve estimation. The volume average of RSS was reduced by the maximum of 77% in four volunteers' results with both the realignment and the averaged b0 images. The FA-ZDP images revealed the improvement by realignment such as the contrast of corpus callosum and suppression of abnormal FA at cerebral sulcus. The number of additional b0 images accounted for 3% of the total number of DWIs, which suggests its feasibility for future clinical application.

  16. Oblique wave motion over multiple submerged porous bars near a vertical wall

    NASA Astrophysics Data System (ADS)

    Zhao, Yang; Liu, Yong; Li, Huajun; Chang, Anteng

    2017-08-01

    This study examines oblique wave motion over multiple submerged porous bars in front of a vertical wall. Based on linear potential theory, an analytical solution for the present problem is developed using matched eigenfunction expansions. A complex dispersion relation is adopted to describe the wave elevation and energy dissipation over submerged porous bars. In the analytical solution, no limitations on the bar number, bar size, and spacing between adjacent bars are set. The convergence of the analytical solution is satisfactory, and the correctness of the analytical solution is confirmed by an independently developed multi-domain BEM (boundary element method) solution. Numerical examples are presented to examine the reflection and transmission coefficients of porous bars, C R and C T , respectively, for engineering applications. The calculation results show that when the sum of widths for all the porous bars is fixed, increasing the bar number can significantly improve the sheltering function of the bars. Increasing the bar height can cause more wave energy dissipation and lower C R and C T . The spacing between adjacent bars and the spacing between the last bar and the vertical wall are the key parameters affecting C R and C T . The proposed analytical method may be used to analyze the hydrodynamic performance of submerged porous bars in preliminary engineering designs.

  17. Estimation of affine motion from projection data using a mass conservation model.

    PubMed

    Negahdar, Mohammadreza; Amini, Amir A

    2011-01-01

    An approximate model for the effect of respiration is that the cross section of the thoracic area under interrogation experience time-varying magnification and displacement along two perpendicular axes - we propose to model this motion as parametric affine motion. A theoretical framework for determination of parameters of affine motion modeling the global respiratory motion based on the sinogram data in the projection domain is described. It is assumed that the spatial image considered is a density image where conservation of mass holds.

  18. Cardiorespiratory motion-compensated micro-CT image reconstruction using an artifact model-based motion estimation.

    PubMed

    Brehm, Marcus; Sawall, Stefan; Maier, Joscha; Sauppe, Sebastian; Kachelrieß, Marc

    2015-04-01

    Cardiac in vivo micro-CT imaging of small animals typically requires double gating due to long scan times and high respiratory rates. The simultaneous respiratory and cardiac gating can either be done prospectively or retrospectively. In any case, for true 5D imaging, i.e., three spatial dimensions plus one respiratory-temporal dimension plus one cardiac temporal dimension, the amount of information corresponding to a given respiratory and cardiac phase is orders of magnitude lower than the total amount of information acquired. Achieving similar image quality for 5D than for usual 3D investigations would require increasing the amount of data and thus the applied dose to the animal. Therefore, the goal is phase-correlated imaging with high image quality but without increasing the dose level. To achieve this, the authors propose a new image reconstruction algorithm that makes use of all available projection data, also of that corresponding to other motion windows. In particular, the authors apply a motion-compensated image reconstruction approach that sequentially compensates for respiratory and cardiac motion to decrease the impact of sparsification. In that process, all projection data are used no matter which motion phase they were acquired in. Respiratory and cardiac motion are compensated for by using motion vector fields. These motion vector fields are estimated from initial phase-correlated reconstructions based on a deformable registration approach. To decrease the sensitivity of the registration to sparse-view artifacts, an artifact model-based approach is used including a cyclic consistent nonrigid registration algorithm. The preliminary results indicate that the authors' approach removes the sparse-view artifacts of conventional phase-correlated reconstructions while maintaining temporal resolution. In addition, it achieves noise levels and spatial resolution comparable to that of nongated reconstructions due to the improved dose usage. By using the

  19. Model and parametric uncertainty in source-based kinematic models of earthquake ground motion

    USGS Publications Warehouse

    Hartzell, Stephen; Frankel, Arthur; Liu, Pengcheng; Zeng, Yuehua; Rahman, Shariftur

    2011-01-01

    Four independent ground-motion simulation codes are used to model the strong ground motion for three earthquakes: 1994 Mw 6.7 Northridge, 1989 Mw 6.9 Loma Prieta, and 1999 Mw 7.5 Izmit. These 12 sets of synthetics are used to make estimates of the variability in ground-motion predictions. In addition, ground-motion predictions over a grid of sites are used to estimate parametric uncertainty for changes in rupture velocity. We find that the combined model uncertainty and random variability of the simulations is in the same range as the variability of regional empirical ground-motion data sets. The majority of the standard deviations lie between 0.5 and 0.7 natural-log units for response spectra and 0.5 and 0.8 for Fourier spectra. The estimate of model epistemic uncertainty, based on the different model predictions, lies between 0.2 and 0.4, which is about one-half of the estimates for the standard deviation of the combined model uncertainty and random variability. Parametric uncertainty, based on variation of just the average rupture velocity, is shown to be consistent in amplitude with previous estimates, showing percentage changes in ground motion from 50% to 300% when rupture velocity changes from 2.5 to 2.9 km/s. In addition, there is some evidence that mean biases can be reduced by averaging ground-motion estimates from different methods.

  20. How Many Objects are You Worth? Quantification of the Self-Motion Load on Multiple Object Tracking.

    PubMed

    Thomas, Laura E; Seiffert, Adriane E

    2011-01-01

    Perhaps walking and chewing gum is effortless, but walking and tracking moving objects is not. Multiple object tracking is impaired by walking from one location to another, suggesting that updating location of the self puts demands on object tracking processes. Here, we quantified the cost of self-motion in terms of the tracking load. Participants in a virtual environment tracked a variable number of targets (1-5) among distractors while either staying in one place or moving along a path that was similar to the objects' motion. At the end of each trial, participants decided whether a probed dot was a target or distractor. As in our previous work, self-motion significantly impaired performance in tracking multiple targets. Quantifying tracking capacity for each individual under move versus stay conditions further revealed that self-motion during tracking produced a cost to capacity of about 0.8 (±0.2) objects. Tracking your own motion is worth about one object, suggesting that updating the location of the self is similar, but perhaps slightly easier, than updating locations of objects.

  1. A Fully Nonlinear, Dynamically Consistent Numerical Model for Solid-Body Ship Motion. 1. Ship Motion with Fixed Heading

    DTIC Science & Technology

    2010-01-01

    various ship hulls for heave, roll and pitch motion. In addition to the benchmark cases, numerical experiments are also carried out for strongly...Uy and Uz are called roll , pitch and yaw, respectively. In the model reference frame the x-axis is the ship heading direction (from the stern to the...unsteady ship motions ( roll , pitch and heave) are compared and cross-examined. Reported here are selected cases, which are the extreme scenarios of the

  2. Sensory versus motor loci for integration of multiple motion signals in smooth pursuit eye movements and human motion perception.

    PubMed

    Niu, Yu-Qiong; Lisberger, Stephen G

    2011-08-01

    We have investigated how visual motion signals are integrated for smooth pursuit eye movements by measuring the initiation of pursuit in monkeys for pairs of moving stimuli of the same or differing luminance. The initiation of pursuit for pairs of stimuli of the same luminance could be accounted for as a vector average of the responses to the two stimuli singly. When stimuli comprised two superimposed patches of moving dot textures, the brighter stimulus suppressed the inputs from the dimmer stimulus, so that the initiation of pursuit became winner-take-all when the luminance ratio of the two stimuli was 8 or greater. The dominance of the brighter stimulus could be not attributed to either the latency difference or the ratio of the eye accelerations for the bright and dim stimuli presented singly. When stimuli comprised either spot targets or two patches of dots moving across separate locations in the visual field, the brighter stimulus had a much weaker suppressive influence; the initiation of pursuit could be accounted for by nearly equal vector averaging of the responses to the two stimuli singly. The suppressive effects of the brighter stimulus also appeared in human perceptual judgments, but again only for superimposed stimuli. We conclude that one locus of the interaction of two moving visual stimuli is shared by perception and action and resides in local inhibitory connections in the visual cortex. A second locus resides deeper in sensory-motor processing and may be more closely related to action selection than to stimulus selection.

  3. Sensory versus motor loci for integration of multiple motion signals in smooth pursuit eye movements and human motion perception

    PubMed Central

    Niu, Yu-Qiong

    2011-01-01

    We have investigated how visual motion signals are integrated for smooth pursuit eye movements by measuring the initiation of pursuit in monkeys for pairs of moving stimuli of the same or differing luminance. The initiation of pursuit for pairs of stimuli of the same luminance could be accounted for as a vector average of the responses to the two stimuli singly. When stimuli comprised two superimposed patches of moving dot textures, the brighter stimulus suppressed the inputs from the dimmer stimulus, so that the initiation of pursuit became winner-take-all when the luminance ratio of the two stimuli was 8 or greater. The dominance of the brighter stimulus could be not attributed to either the latency difference or the ratio of the eye accelerations for the bright and dim stimuli presented singly. When stimuli comprised either spot targets or two patches of dots moving across separate locations in the visual field, the brighter stimulus had a much weaker suppressive influence; the initiation of pursuit could be accounted for by nearly equal vector averaging of the responses to the two stimuli singly. The suppressive effects of the brighter stimulus also appeared in human perceptual judgments, but again only for superimposed stimuli. We conclude that one locus of the interaction of two moving visual stimuli is shared by perception and action and resides in local inhibitory connections in the visual cortex. A second locus resides deeper in sensory-motor processing and may be more closely related to action selection than to stimulus selection. PMID:21593392

  4. A Fully Nonlinear, Dynamically Consistent Numerical Model for Solid-Body Ship Motion. I. Ship Motion with Fixed Heading

    NASA Technical Reports Server (NTRS)

    Lin, Ray-Quing; Kuang, Weijia

    2011-01-01

    In this paper, we describe the details of our numerical model for simulating ship solidbody motion in a given environment. In this model, the fully nonlinear dynamical equations governing the time-varying solid-body ship motion under the forces arising from ship wave interactions are solved with given initial conditions. The net force and moment (torque) on the ship body are directly calculated via integration of the hydrodynamic pressure over the wetted surface and the buoyancy effect from the underwater volume of the actual ship hull with a hybrid finite-difference/finite-element method. Neither empirical nor free parametrization is introduced in this model, i.e. no a priori experimental data are needed for modelling. This model is benchmarked with many experiments of various ship hulls for heave, roll and pitch motion. In addition to the benchmark cases, numerical experiments are also carried out for strongly nonlinear ship motion with a fixed heading. These new cases demonstrate clearly the importance of nonlinearities in ship motion modelling.

  5. Mapping vulnerability of multiple aquifers using multiple models and fuzzy logic to objectively derive model structures.

    PubMed

    Nadiri, Ata Allah; Sedghi, Zahra; Khatibi, Rahman; Gharekhani, Maryam

    2017-09-01

    Driven by contamination risks, mapping Vulnerability Indices (VI) of multiple aquifers (both unconfined and confined) is investigated by integrating the basic DRASTIC framework with multiple models overarched by Artificial Neural Networks (ANN). The DRASTIC framework is a proactive tool to assess VI values using the data from the hydrosphere, lithosphere and anthroposphere. However, a research case arises for the application of multiple models on the ground of poor determination coefficients between the VI values and non-point anthropogenic contaminants. The paper formulates SCFL models, which are derived from the multiple model philosophy of Supervised Committee (SC) machines and Fuzzy Logic (FL) and hence SCFL as their integration. The Fuzzy Logic-based (FL) models include: Sugeno Fuzzy Logic (SFL), Mamdani Fuzzy Logic (MFL), Larsen Fuzzy Logic (LFL) models. The basic DRASTIC framework uses prescribed rating and weighting values based on expert judgment but the four FL-based models (SFL, MFL, LFL and SCFL) derive their values as per internal strategy within these models. The paper reports that FL and multiple models improve considerably on the correlation between the modeled vulnerability indices and observed nitrate-N values and as such it provides evidence that the SCFL multiple models can be an alternative to the basic framework even for multiple aquifers. The study area with multiple aquifers is in Varzeqan plain, East Azerbaijan, northwest Iran. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. Nonlinear dynamic modeling of a simple flexible rotor system subjected to time-variable base motions

    NASA Astrophysics Data System (ADS)

    Chen, Liqiang; Wang, Jianjun; Han, Qinkai; Chu, Fulei

    2017-09-01

    Rotor systems carried in transportation system or under seismic excitations are considered to have a moving base. To study the dynamic behavior of flexible rotor systems subjected to time-variable base motions, a general model is developed based on finite element method and Lagrange's equation. Two groups of Euler angles are defined to describe the rotation of the rotor with respect to the base and that of the base with respect to the ground. It is found that the base rotations would cause nonlinearities in the model. To verify the proposed model, a novel test rig which could simulate the base angular-movement is designed. Dynamic experiments on a flexible rotor-bearing system with base angular motions are carried out. Based upon these, numerical simulations are conducted to further study the dynamic response of the flexible rotor under harmonic angular base motions. The effects of base angular amplitude, rotating speed and base frequency on response behaviors are discussed by means of FFT, waterfall, frequency response curve and orbits of the rotor. The FFT and waterfall plots of the disk horizontal and vertical vibrations are marked with multiplications of the base frequency and sum and difference tones of the rotating frequency and the base frequency. Their amplitudes will increase remarkably when they meet the whirling frequencies of the rotor system.

  7. New Ground Motion Prediction Models for Caucasus Region

    NASA Astrophysics Data System (ADS)

    Jorjiashvili, N.

    2012-12-01

    The Caucasus is a region of numerous natural hazards and ensuing disasters. Analysis of the losses due to past disasters indicates the those most catastrophic in the region have historically been due to strong earthquakes. Estimation of expected ground motion is a fundamental earthquake hazard assessment. The most commonly used parameter for attenuation relation is peak ground acceleration because this parameter gives useful information for Seismic Hazard Assessment. Because of this, many peak ground acceleration attenuation relations have been developed by different authors. Besides, a few attenuation relations were developed for Caucasus region: Ambraseys et al. (1996,2005) which were based on entire European region and they were not focused locally on Caucasus Region; Smit et.al. (2000) that was based on a small amount of acceleration data that really is not enough. Since 2003 construction of Georgian Digital Seismic Network has started with the help of number of International organizations, Projects and Private companies. The works conducted involved scientific as well as organizational activities: Resolving technical problems concerning communication and data transmission. Thus, today we have a possibility to get real time data and make scientific research based on digital seismic data. Generally, ground motion and damage are influenced by the magnitude of the earthquake, the distance from the seismic source to site, the local ground conditions and the characteristics of buildings. Estimation of expected ground motion is a fundamental earthquake hazard assessment. This is the reason why this topic is emphasized in this study. In this study new GMP models are obtained based on new data from Georgian seismic network and also from neighboring countries. Estimation of models are obtained by classical, statistical way, regression analysis. Also site ground conditions are considered because the same earthquake recorded at the same distance may cause different damage

  8. Validating a Dynamic Earthquake Model to Produce Realistic Ground Motion

    NASA Astrophysics Data System (ADS)

    Andrews, D. J.; Ma, S.

    2015-12-01

    A dynamic earthquake model is validated by finding good agreement with an empirical ground motion prediction equation. The model replaces detailed deterministic processes on the fault with a stochastic emergent law. Initial stress on a fault plane is heterogeneous with a power-law spectrum that is self-similar. Rupture stops naturally. Rupture extent and moment are determined primarily by the specified lowest Fourier mode of initial stress. Higher modes are random with a self-similar spectrum that is tied to the amplitude of the lowest mode. Ten random realizations are calculated with a velocity structure for a hard rock site. The calculated mean response spectrum for M7 at a distance of 10 km agrees the with the GMPE of Boore et al (2013) within 0.25 of one standard deviation at periods from 0.3 seconds to 10 seconds. The agreement could be improved by using a more refined relation of the spatial stress spectrum to the amplitude of the lowest mode. The standard deviation of the calculated ground motion is somewhat smaller than the GMPE, but it depends on other rupture parameters and needs more investigation.

  9. Continuous motion decoding from EMG using independent component analysis and adaptive model training.

    PubMed

    Zhang, Qin; Xiong, Caihua; Chen, Wenbin

    2014-01-01

    Surface Electromyography (EMG) is popularly used to decode human motion intention for robot movement control. Traditional motion decoding method uses pattern recognition to provide binary control command which can only move the robot as predefined limited patterns. In this work, we proposed a motion decoding method which can accurately estimate 3-dimensional (3-D) continuous upper limb motion only from multi-channel EMG signals. In order to prevent the muscle activities from motion artifacts and muscle crosstalk which especially obviously exist in upper limb motion, the independent component analysis (ICA) was applied to extract the independent source EMG signals. The motion data was also transferred from 4-manifold to 2-manifold by the principle component analysis (PCA). A hidden Markov model (HMM) was proposed to decode the motion from the EMG signals after the model trained by an adaptive model identification process. Experimental data were used to train the decoding model and validate the motion decoding performance. By comparing the decoded motion with the measured motion, it is found that the proposed motion decoding strategy was feasible to decode 3-D continuous motion from EMG signals.

  10. [Bionic model for coordinated head-eye motion control].

    PubMed

    Mao, Xiaobo; Chen, Tiejun

    2011-10-01

    The relationships between eye movements and head movements of the primate during gaze shifts are analyzed in detail in the present paper. Applying the mechanisms of neurophysiology to engineering domain, we have improved the robot eye-head coordination. A bionic control strategy of coordinated head-eye motion was proposed. The processes of gaze shifts are composed of an initial fast phase followed by a slow phase. In the fast phase saccade eye movements and slow head movements were combined, which cooperate to bring gaze from an initial resting position toward the new target rapidly, while in the slow phase the gaze stability and target fixation were ensured by the action of the vestibulo-ocular reflex (VOR) where the eyes and head rotate by equal amplitudes in opposite directions. A bionic gaze control model was given. The simulation results confirmed the effectiveness of the model by comparing with the results of neurophysiology experiments.

  11. Free-breathing intra- and intersubject respiratory motion capturing, modeling, and prediction

    NASA Astrophysics Data System (ADS)

    Klinder, Tobias; Lorenz, Cristian; Ostermann, Jörn

    2009-02-01

    Respiration-induced organ motion can limit the accuracy required for many clinical applications working on the thorax or upper abdomen. One approach to reduce the uncertainty of organ location caused by respiration is to use prior knowledge of breathing motion. In this work, we deal with the extraction and modeling of lung motion fields based on free-breathing 4D-CT data sets of 36 patients. Since data was acquired for radiotherapy planning, images of the same patient were available over different weeks of treatment. Motion field extraction is performed using an iterative shape-constrained deformable model approach. From the extracted motion fields, intra- and inter-subject motion models are built and adapted in a leave-one-out test. The created models capture the motion of corresponding landmarks over the breathing cycle. Model adaptation is then performed by examplarily assuming the diaphragm motion to be known. Although, respiratory motion shows a repetitive character, it is known that patients' variability in breathing pattern impedes motion estimation. However, with the created motion models, we obtained a mean error between the phases of maximal distance of 3.4 mm for the intra-patient and 4.2 mm for the inter-patient study when assuming the diaphragm motion to be known.

  12. Cervical spine motion in manual versus Jackson table turning methods in a cadaveric global instability model.

    PubMed

    DiPaola, Matthew J; DiPaola, Christian P; Conrad, Bryan P; Horodyski, MaryBeth; Del Rossi, Gianluca; Sawers, Andrew; Bloch, David; Rechtine, Glenn R

    2008-06-01

    A study of spine biomechanics in a cadaver model. To quantify motion in multiple axes created by transfer methods from stretcher to operating table in the prone position in a cervical global instability model. Patients with an unstable cervical spine remain at high risk for further secondary injury until their spine is adequately surgically stabilized. Previous studies have revealed that collars have significant, but limited benefit in preventing cervical motion when manually transferring patients. The literature proposes multiple methods of patient transfer, although no one method has been universally adopted. To date, no study has effectively evaluated the relationship between spine motion and various patient transfer methods to an operating room table for prone positioning. A global instability was surgically created at C5-6 in 4 fresh cadavers with no history of spine pathology. All cadavers were tested both with and without a rigid cervical collar in the intact and unstable state. Three headrest permutations were evaluated Mayfield (SM USA Inc), Prone View (Dupaco, Oceanside, CA), and Foam Pillow (OSI, Union City, CA). A trained group of medical staff performed each of 2 transfer methods: the "manual" and the "Jackson table" transfer. The manual technique entailed performing a standard rotation of the supine patient on a stretcher to the prone position on the operating room table with in-line manual cervical stabilization. The "Jackson" technique involved sliding the supine patient to the Jackson table (OSI, Union City, CA) with manual in-line cervical stabilization, securing them to the table, then initiating the table's lock and turn mechanism and rotating them into a prone position. An electromagnetic tracking device captured angular motion between the C5 and C6 vertebral segments. Repeated measures statistical analysis was performed to evaluate the following conditions: collar use (2 levels), headrest (3 levels), and turning technique (2 levels). For all

  13. Computer coordination of limb motion for locomotion of a multiple-armed robot for space assembly

    NASA Technical Reports Server (NTRS)

    Klein, C. A.; Patterson, M. R.

    1982-01-01

    Consideration is given to a possible robotic system for the construction of large space structures, which may be described as a multiple general purpose arm manipulator vehicle that can walk over the structure under construction to a given site for further work. A description is presented of the locomotion of such a vehicle, modeling its arms in terms of a currently available industrial manipulator. It is noted that for whatever maximum speed of operation is chosen, rapid changes in robot velocity create situations in which already-selected handholds are no longer practical. A step is added to the 'free gait' walking algorithm in order to solve this problem.

  14. Learning medical diagnosis models from multiple experts.

    PubMed

    Valizadegan, Hamed; Nguyen, Quang; Hauskrecht, Milos

    2012-01-01

    Building classification models from clinical data often requires labeling examples by human experts. However, it is difficult to obtain a perfect set of labels everyone agrees on because medical data are typically very complicated and it is quite common that different experts have different opinions on the same patient data. A solution that has been recently explored by the research community is learning from multiple experts/annotators. The objective of learning from multiple experts is to model different characteristics of the human experts and combine them to obtain a consensus model. In this work, we study and develop a new probabilistic approach for learning classification models from labels provided by multiple experts. Our method explicitly models and incorporates three characteristics of annotators into the learning process: their specific prediction model, consistency and bias. We show that in addition to building a superior classification model, our method also helps to model behavior of annotators. We applied the proposed method to learn different characteristics of Physicians labeling clinical records for Heparin Induced Thrombocytopenia (HIT) and combine them in order to obtain a final classifier.

  15. Robotic learning of motion using demonstrations and statistical models for surgical simulation.

    PubMed

    Yang, Tao; Chui, Chee Kong; Liu, Jiang; Huang, Weimin; Su, Yi; Chang, Stephen K Y

    2014-09-01

    In robotic-assisted surgical training, the expertise of surgeons in maneuvering surgical instruments may be utilized to provide the motion trajectories for teaching. However, the motion primitives for trajectory planning are not known until the motion trajectory is generalized. We hypothesize that a generic model that encodes surgical skills using demonstrations and statistical models can be used by the surgical training robot to determine the motion primitive base on the motion trajectory. The generic model was developed from twenty-two sets of motion trajectories of soft tissue division with laparoscopic scissors collected from a robotic laparoscopic surgical training system. Adaptive mean shift method with initial bandwidth determined by the plug-in-rule method was used to identify the primitives in the motion trajectories. Gaussian Mixture Model was applied to model the underlying motion structure. Gaussian Mixture Regression was then applied to reconstruct a generic motion trajectory for the task. The generic model and proposed method were investigated in experiments. Motion trajectory of tissue division was model and reconstructed. The motion model which was trained based on primitives determined by adaptive mean shift method produced RMS error of 3.05° and 3.08° with respect to the demonstrated trajectories of left and right instruments, respectively. The RMS error was smaller than that of k-means method and fixed bandwidth mean shift method. The dexterous features in the demonstrations were also preserved. Surgical tasks can be modeled using Gaussian Mixture Model and motion primitives identified by adaptive mean shift method with minimum user intervention. Generic motion trajectory has been successfully reconstructed based on the motion model. Investigation on the effectiveness of this method and generic model for surgical training is ongoing.

  16. A New Method for Motion Planning of Rotating Bodies under Multiple Constraints

    NASA Astrophysics Data System (ADS)

    Nishiyama, Takehiro; Yamada, Katsuhiko; Yoshikawa, Shoji

    This paper presents a new method for generating motion profiles of rotating bodies, for example, the joint angle motion of mechanical systems such as space manipulators and antennas. In the planning of a motion from the given initial conditions to the final conditions, there are many constraints that should be considered, for example, actuator torque limits, rate limits, jerk limits, etc. Furthermore, flexibility of a system cannot be ignored in general. Vibration suppression is of great importance in some applications. For stationary boundary conditions (rest-to-rest cases), if the only constraint is the torque limit, a simple bang-bang type profile is the optimal one. However, if we consider more general boundary conditions, complex constraints, and vibration suppression conditions, the problem becomes considerably complicated. In this study, motion planning for a fixed motion time is considered. The control input or the acceleration of the motion is expressed as a linear superposition of triangle waves whose weight coefficients are determined in order to optimize the motion profile. In this formulation, all the boundary conditions and several constraints, including vibration suppression conditions, are expressed as linear equality and inequality constraints. Therefore, by appropriately setting the performance index, the problem becomes a linear programming problem and can be solved efficiently.

  17. Plate Motions Predicted from Global Dynamic Models and Seismic Tomography: The Problem of North American Plate Motion

    NASA Astrophysics Data System (ADS)

    Liu, S.; King, S. D.; Adam, C. M.

    2016-12-01

    Seismic tomography is a snapshot of the mantle convection system and provides important constraints on Earth's internal dynamics. An increasing number of global seismic tomography models along with various rheological structures have been used to compute mantle flow pattern and the resulting surface expressions, including dynamic topography and geoid. Accurately predicting the plate motion from the mantle dynamic models is a challenge particularly with the newest generation of seismic tomography models (e.g., S40RTS, SAVANI), especially for the North American plate which only has a little subduction along it's boundary. The difficulties include the uncertainty of the velocity-to-density scaling, discrepancies between different seismic tomography models, and the computational technology to solve for global mantle flow with observationally constrained high resolution models. We use the code ASPECT (Advanced Solver for Problems in Earth CovecTion) to make a series of tests to derive mantle flow pattern from different global seismic tomography models and rheological structures. We further make a quantitative statistical comparison between the modeled and observed plate motions in terms of flow magnitude, flow direction, and plateness within each plate area. We investigate how the velocity-to-density scaling, the features of seismic tomography models, and the lateral rheological structures of the lithosphere and upper mantle influence the modeled plate motions. We find that the velocity-to-density scaling mainly changes the flow magnitude and has little impact on the flow direction. The results of different seismic tomography models are similar broadly but can be quite different in some regions. The presence of lateral viscosity variations including stiff cratons, weak plate boundary zones, and high viscosity slabs along with density variations from seafloor age and subducting slabs can improve the fit to observed plate motions. With a very small fraction of subduction

  18. Multiplicative earthquake likelihood models incorporating strain rates

    NASA Astrophysics Data System (ADS)

    Rhoades, D. A.; Christophersen, A.; Gerstenberger, M. C.

    2017-01-01

    SUMMARYWe examine the potential for strain-rate variables to improve long-term earthquake likelihood <span class="hlt">models</span>. We derive a set of <span class="hlt">multiplicative</span> hybrid earthquake likelihood <span class="hlt">models</span> in which cell rates in a spatially uniform baseline <span class="hlt">model</span> are scaled using combinations of covariates derived from earthquake catalogue data, fault data, and strain-rates for the New Zealand region. Three components of the strain rate estimated from GPS data over the period 1991-2011 are considered: the shear, rotational and dilatational strain rates. The hybrid <span class="hlt">model</span> parameters are optimised for earthquakes of M 5 and greater over the period 1987-2006 and tested on earthquakes from the period 2012-2015, which is independent of the strain rate estimates. The shear strain rate is overall the most informative individual covariate, as indicated by Molchan error diagrams as well as <span class="hlt">multiplicative</span> <span class="hlt">modelling</span>. Most <span class="hlt">models</span> including strain rates are significantly more informative than the best <span class="hlt">models</span> excluding strain rates in both the fitting and testing period. A hybrid that combines the shear and dilatational strain rates with a smoothed seismicity covariate is the most informative <span class="hlt">model</span> in the fitting period, and a simpler <span class="hlt">model</span> without the dilatational strain rate is the most informative in the testing period. These results have implications for probabilistic seismic hazard analysis and can be used to improve the background <span class="hlt">model</span> component of medium-term and short-term earthquake forecasting <span class="hlt">models</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/21220113','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/21220113"><span>Portrayal of complex dynamic properties of sugarcane defensin 5 by NMR: <span class="hlt">multiple</span> <span class="hlt">motions</span> associated with membrane interaction.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>de Paula, Viviane Silva; Razzera, Guilherme; Barreto-Bergter, Eliana; Almeida, Fabio C L; Valente, Ana Paula</p> <p>2011-01-12</p> <p>Defensins are essentially ancient natural antibiotics with potent activity extending from lower organisms to humans. Sd5 is a recently described antifungal defensin that appears to be the result of a recent gain of function. We reported here the solution NMR structure of Sd5 and characterized the backbone dynamics in the free state and in the presence of membrane <span class="hlt">models</span>. (15)N relaxation dispersion measurements indicate intrinsic conformational exchange processes, showing two clear distinct k(ex), 490 and 1800 s(-1). These <span class="hlt">multiple</span> <span class="hlt">motions</span> may be related to transient twisting or breathing of the α helix and β sheet. The stages of membrane recognition and disruption by Sd5 over a large timescale range were mapped and demonstrated that Sd5 in solution sampled an ensemble of different conformations, of which a subset is selected upon membrane binding. Defensins share similar structures, but we demonstrated here that their dynamics can be extremely diverse. Copyright © 2011 Elsevier Ltd. All rights reserved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013JSeis..17.1157R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013JSeis..17.1157R"><span>Statistical <span class="hlt">modeling</span> of ground <span class="hlt">motion</span> relations for seismic hazard analysis</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Raschke, Mathias</p> <p>2013-10-01</p> <p>We introduce a new approach for ground <span class="hlt">motion</span> relations (GMR) in the probabilistic seismic hazard analysis (PSHA), being influenced by the extreme value theory of mathematical statistics. Therein, we understand a GMR as a random function. We derive mathematically the principle of area equivalence, wherein two alternative GMRs have an equivalent influence on the hazard if these GMRs have equivalent area functions. This includes local biases. An interpretation of the difference between these GMRs (an actual and a <span class="hlt">modeled</span> one) as a random component leads to a general overestimation of residual variance and hazard. Beside this, we discuss important aspects of classical approaches and discover discrepancies with the state of the art of stochastics and statistics (<span class="hlt">model</span> selection and significance, test of distribution assumptions, extreme value statistics). We criticize especially the assumption of logarithmic normally distributed residuals of maxima like the peak ground acceleration (PGA). The natural distribution of its individual random component (equivalent to exp( ɛ 0) of Joyner and Boore, Bull Seism Soc Am 83(2):469-487, 1993) is the generalized extreme value. We show by numerical researches that the actual distribution can be hidden and a wrong distribution assumption can influence the PSHA negatively as the negligence of area equivalence does. Finally, we suggest an estimation concept for GMRs of PSHA with a regression-free variance estimation of the individual random component. We demonstrate the advantages of event-specific GMRs by analyzing data sets from the PEER strong <span class="hlt">motion</span> database and estimate event-specific GMRs. Therein, the majority of the best <span class="hlt">models</span> base on an anisotropic point source approach. The residual variance of logarithmized PGA is significantly smaller than in previous <span class="hlt">models</span>. We validate the estimations for the event with the largest sample by empirical area functions, which indicate the appropriate <span class="hlt">modeling</span> of the GMR by an anisotropic</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li class="active"><span>13</span></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_13 --> <div id="page_14" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li class="active"><span>14</span></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="261"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=84065&keyword=dentistry&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50','EPA-EIMS'); return false;" href="http://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=84065&keyword=dentistry&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50"><span>MICROARRAY DATA ANALYSIS USING <span class="hlt">MULTIPLE</span> STATISTICAL <span class="hlt">MODELS</span></span></a></p> <p><a target="_blank" href="http://oaspub.epa.gov/eims/query.page">EPA Science Inventory</a></p> <p></p> <p></p> <p>Microarray Data Analysis Using <span class="hlt">Multiple</span> Statistical <span class="hlt">Models</span><br><br>Wenjun Bao1, Judith E. Schmid1, Amber K. Goetz1, Ming Ouyang2, William J. Welsh2,Andrew I. Brooks3,4, ChiYi Chu3,Mitsunori Ogihara3,4, Yinhe Cheng5, David J. Dix1. 1National Health and Environmental Effects Researc...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=84065&keyword=bioinformatics+AND+dataset&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50&CFID=78796574&CFTOKEN=13907985','EPA-EIMS'); return false;" href="http://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=84065&keyword=bioinformatics+AND+dataset&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50&CFID=78796574&CFTOKEN=13907985"><span>MICROARRAY DATA ANALYSIS USING <span class="hlt">MULTIPLE</span> STATISTICAL <span class="hlt">MODELS</span></span></a></p> <p><a target="_blank" href="http://oaspub.epa.gov/eims/query.page">EPA Science Inventory</a></p> <p></p> <p></p> <p>Microarray Data Analysis Using <span class="hlt">Multiple</span> Statistical <span class="hlt">Models</span><br><br>Wenjun Bao1, Judith E. Schmid1, Amber K. Goetz1, Ming Ouyang2, William J. Welsh2,Andrew I. Brooks3,4, ChiYi Chu3,Mitsunori Ogihara3,4, Yinhe Cheng5, David J. Dix1. 1National Health and Environmental Effects Researc...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19900044291&hterms=divided+attention&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Ddivided%2Battention','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19900044291&hterms=divided+attention&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Ddivided%2Battention"><span>Predictive performance <span class="hlt">models</span> and <span class="hlt">multiple</span> task performance</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Wickens, Christopher D.; Larish, Inge; Contorer, Aaron</p> <p>1989-01-01</p> <p>Five <span class="hlt">models</span> that predict how performance of <span class="hlt">multiple</span> tasks will interact in complex task scenarios are discussed. The <span class="hlt">models</span> are shown in terms of the assumptions they make about human operator divided attention. The different assumptions about attention are then empirically validated in a multitask helicopter flight simulation. It is concluded from this simulation that the most important assumption relates to the coding of demand level of different component tasks.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19900044291&hterms=inge&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dinge','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19900044291&hterms=inge&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dinge"><span>Predictive performance <span class="hlt">models</span> and <span class="hlt">multiple</span> task performance</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Wickens, Christopher D.; Larish, Inge; Contorer, Aaron</p> <p>1989-01-01</p> <p>Five <span class="hlt">models</span> that predict how performance of <span class="hlt">multiple</span> tasks will interact in complex task scenarios are discussed. The <span class="hlt">models</span> are shown in terms of the assumptions they make about human operator divided attention. The different assumptions about attention are then empirically validated in a multitask helicopter flight simulation. It is concluded from this simulation that the most important assumption relates to the coding of demand level of different component tasks.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015P%26SS..108...31L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015P%26SS..108...31L"><span>Cellinoid shape <span class="hlt">model</span> for <span class="hlt">multiple</span> light curves</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lu, Xiao-Ping; Ip, Wing-Huen</p> <p>2015-04-01</p> <p>Extended from the ellipsoid shape, cellinoid shape <span class="hlt">model</span> consists of eight octants from eight different ellipsoids with the constraint that the adjacent octants have the same semi-axes in common. With the asymmetric shape, cellinoid shape <span class="hlt">model</span> could be adopted in simulating the irregular shapes of asteroids. In this article, we attempt to apply cellinoid shape <span class="hlt">model</span> to <span class="hlt">multiple</span> light curves observed in various geometries and present some techniques to make the whole inverse process more efficient. Finally numerical experiments confirm that cellinoid shape <span class="hlt">model</span> could derive the physical parameters of asteroids from both of synthetic and real light curves.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19790009341','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19790009341"><span>A <span class="hlt">model</span> for the pilot's use of <span class="hlt">motion</span> cues in roll-axis tracking tasks</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Levison, W. H.; Junker, A. M.</p> <p>1977-01-01</p> <p>Simulated target-following and disturbance-regulation tasks were explored with subjects using visual-only and combined visual and <span class="hlt">motion</span> cues. The effects of <span class="hlt">motion</span> cues on task performance and pilot response behavior were appreciably different for the two task configurations and were consistent with data reported in earlier studies for similar task configurations. The optimal-control <span class="hlt">model</span> for pilot/vehicle systems provided a task-independent framework for accounting for the pilot's use of <span class="hlt">motion</span> cues. Specifically, the availability of <span class="hlt">motion</span> cues was <span class="hlt">modeled</span> by augmenting the set of perceptual variables to include position, rate, acceleration, and accleration-rate of the <span class="hlt">motion</span> simulator, and results were consistent with the hypothesis of attention-sharing between visual and <span class="hlt">motion</span> variables. This straightforward informational <span class="hlt">model</span> allowed accurate <span class="hlt">model</span> predictions of the effects of <span class="hlt">motion</span> cues on a variety of response measures for both the target-following and disturbance-regulation tasks.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EGUGA..1710769S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EGUGA..1710769S"><span>Early breakup of Gondwana: constraints from global plate <span class="hlt">motion</span> <span class="hlt">models</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Seton, Maria; Zahirovic, Sabin; Williams, Simon; Whittaker, Joanne; Gibbons, Ana; Muller, Dietmar; Brune, Sascha; Heine, Christian</p> <p>2015-04-01</p> <p>Supercontinent break-up and amalgamation is a fundamental Earth cycle, contributing to long-term sea-level fluctuations, species diversity and extinction events, long-term greenhouse-icehouse cycles and changes in the long-wavelength density structure of the mantle. The most recent and best-constrained example involves the fragmentation of Gondwana, starting with rifting between Africa/Madagascar and Antarctica in the Early Jurassic and ending with the separation of the Lord Howe microcontinental blocks east of Australia in the Late Cretaceous. Although the first order configuration of Gondwana within modern reconstructions appears similar to that first proposed by Wegener a century ago, recent studies utilising a wealth of new geophysical and geological data provide a much more detailed picture of relative plate <span class="hlt">motions</span> both during rifting and subsequent seafloor spreading. We present our latest global plate <span class="hlt">motion</span> <span class="hlt">model</span> that includes extensive, new regional analyses. These include: South Atlantic rifting, which started at 150 Ma and propagated into cratonic Africa by 145 Ma (Heine et al., 2013); rifting and early seafloor spreading between Australia, India and Antarctica, which reconciles the fit between Broken Ridge-Kergulean Plateau and the eastern Tasman region (Whittaker et al., 2013); rifting of continental material from northeastern Gondwana and its accretion onto Eurasia and SE Asia including a new <span class="hlt">model</span> of microcontinent formation and early seafloor spreading in the eastern Indian Ocean (Gibbons et al., 2012; 2013; in review; Williams et al., 2013; Zahirovic et al., 2014); and a new <span class="hlt">model</span> for the isolation of Zealandia east of Australia, with rifting initiating at 100 Ma until the start of seafloor spreading in the Tasman Sea at ~85 Ma (Williams et al., in prep). Using these reconstructions within the open-source GPlates software, accompanied by a set of evolving plates and plate boundaries, we can explore the factors that govern the behavior of plate</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19930053881&hterms=Harmonic+motion&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3DHarmonic%2Bmotion','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19930053881&hterms=Harmonic+motion&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3DHarmonic%2Bmotion"><span>Digital resolver for helicopter <span class="hlt">model</span> blade <span class="hlt">motion</span> analysis</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Daniels, T. S.; Berry, J. D.; Park, S.</p> <p>1992-01-01</p> <p>The paper reports the development and initial testing of a digital resolver to replace existing analog signal processing instrumentation. Radiometers, mounted directly on one of the fully articulated blades, are electrically connected through a slip ring to analog signal processing circuitry. The measured signals are periodic with azimuth angle and are resolved into harmonic components, with 0 deg over the tail. The periodic nature of the helicopter blade <span class="hlt">motion</span> restricts the frequency content of each flapping and yaw signal to the fundamental and harmonics of the rotor rotational frequency. A minicomputer is employed to collect these data and then plot them graphically in real time. With this and other information generated by the instrumentation, a helicopter test pilot can then adjust the helicopter <span class="hlt">model</span>'s controls to achieve the desired aerodynamic test conditions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3685480','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3685480"><span>A novel CT acquisition and analysis technique for breathing <span class="hlt">motion</span> <span class="hlt">modeling</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Low, Daniel A.; White, Benjamin M.; Lee, Percy P.; Thomas, David H.; Gaudio, Sergio; Jani, Shyam S.; Wu, Xiao; Lamb, James M.</p> <p>2013-01-01</p> <p>Purpose To report on a novel technique for providing artifact-free quantitative 4DCT image datasets for breathing <span class="hlt">motion</span> <span class="hlt">modeling</span>. Methods Commercial clinical four-dimensional computed tomography (4DCT) methods have trouble managing irregular breathing. The resulting images contain <span class="hlt">motion</span>-induced artifacts that can distort structures and inaccurately characterize breathing <span class="hlt">motion</span>. We have developed a novel scanning and analysis method for <span class="hlt">motion</span>-correlated CT that utilizes standard repeated fast helical acquisitions, a simultaneous breathing surrogate measurement, deformable image registration, and a published breathing <span class="hlt">motion</span> <span class="hlt">model</span>. Results The <span class="hlt">motion</span> <span class="hlt">model</span> differs from the CT-measured <span class="hlt">motion</span> by an average of 0.72 mm, indicating the precision of the <span class="hlt">motion</span> <span class="hlt">model</span>. The integral of the divergence of one of the <span class="hlt">motion</span> <span class="hlt">model</span> parameters is predicted to be a constant 1.11 and is found in this case to be 1.09, indicating the accuracy of the <span class="hlt">motion</span> <span class="hlt">model</span>. Conclusions The proposed technique shows promise for providing <span class="hlt">motion</span>-artifact free images at user-selected breathing phases, accurate Hounsfield units, and noise characteristics similar to non-4D CT techniques, at a patient dose similar to or less than current 4DCT techniques. PMID:23640212</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013PMB....58L..31L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013PMB....58L..31L"><span>A novel CT acquisition and analysis technique for breathing <span class="hlt">motion</span> <span class="hlt">modeling</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Low, Daniel A.; White, Benjamin M.; Lee, Percy P.; Thomas, David H.; Gaudio, Sergio; Jani, Shyam S.; Wu, Xiao; Lamb, James M.</p> <p>2013-06-01</p> <p>To report on a novel technique for providing artifact-free quantitative four-dimensional computed tomography (4DCT) image datasets for breathing <span class="hlt">motion</span> <span class="hlt">modeling</span>. Commercial clinical 4DCT methods have difficulty managing irregular breathing. The resulting images contain <span class="hlt">motion</span>-induced artifacts that can distort structures and inaccurately characterize breathing <span class="hlt">motion</span>. We have developed a novel scanning and analysis method for <span class="hlt">motion</span>-correlated CT that utilizes standard repeated fast helical acquisitions, a simultaneous breathing surrogate measurement, deformable image registration, and a published breathing <span class="hlt">motion</span> <span class="hlt">model</span>. The <span class="hlt">motion</span> <span class="hlt">model</span> differs from the CT-measured <span class="hlt">motion</span> by an average of 0.65 mm, indicating the precision of the <span class="hlt">motion</span> <span class="hlt">model</span>. The integral of the divergence of one of the <span class="hlt">motion</span> <span class="hlt">model</span> parameters is predicted to be a constant 1.11 and is found in this case to be 1.09, indicating the accuracy of the <span class="hlt">motion</span> <span class="hlt">model</span>. The proposed technique shows promise for providing <span class="hlt">motion</span>-artifact free images at user-selected breathing phases, accurate Hounsfield units, and noise characteristics similar to non-4D CT techniques, at a patient dose similar to or less than current 4DCT techniques.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015IAUGA..2254916K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015IAUGA..2254916K"><span>Correction to polar <span class="hlt">motion</span> data due to the <span class="hlt">model</span> of geocenter <span class="hlt">motion</span> determined from SLR, GNSS and GRACE observations</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kosek, Wieslaw; Brzezinski, Aleksander; Wnek, Agnieszka; Zbylut-Gorska, Maria; Popinski, Waldemar</p> <p>2015-08-01</p> <p>The geocenter time series determined from observations of satellite geodetic techniques, e.g. Satellite Laser Ranging (SLR) and Global Navigation Satellite Systems(GNSS) represent the variations of the center of mass of the whole Earth (CM) with respect to the Earth center of figure (CF) considered as the origin of the International Terrestrial Reference Frame (ITRF). The CM variations caused by the mass redistribution in the Earth fluid layers can be also expressed by the first degree gravity variations determined from Gravity Recovery and Climate Experiment (GRACE) corrected by the ocean and atmospheric <span class="hlt">models</span> as well as the 2-nd and higher degree coefficients. The wavelet semblance filtering was applied to compute the common geodetic geocenter <span class="hlt">motion</span> <span class="hlt">model</span> from the SLR and GNSS geocenter time series which is in a good agreement in the annual frequency band with geophysical one based on the satellite gravimetry data.The theories of Earth rotation assume always that the underlying Earth-fixed reference system is geocentric, that is its origin is at the instantaneous center of mass. Here we address the following problems: 1) if the observed offset between the CM and CF has significant impact on the equations which are used for interpretation of the observed EOP variations; 2) if and how the observed geocenter <span class="hlt">motion</span> can be used to correct the polar <span class="hlt">motion</span> data while keeping the equations of polar <span class="hlt">motion</span> unchanged. Finally we make an analysis of the time series of corrections and discuss their importance for the current polar <span class="hlt">motion</span> excitation studies.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19890061016&hterms=flight+simulator&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dflight%2Bsimulator','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19890061016&hterms=flight+simulator&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dflight%2Bsimulator"><span>The use of vestibular <span class="hlt">models</span> for design and evaluation of flight simulator <span class="hlt">motion</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Bussolari, Steven R.; Young, Laurence R.; Lee, Alfred T.</p> <p>1989-01-01</p> <p>Quantitative <span class="hlt">models</span> for the dynamics of the human vestibular system are applied to the design and evaluation of flight simulator platform <span class="hlt">motion</span>. An optimal simulator <span class="hlt">motion</span> control algorithm is generated to minimize the vector difference between perceived spatial orientation estimated in flight and in simulation. The <span class="hlt">motion</span> controller has been implemented on the Vertical <span class="hlt">Motion</span> Simulator at NASA Ames Research Center and evaluated experimentally through measurement of pilot performance and subjective rating during VTOL aircraft simulation. In general, pilot performance in a longitudinal tracking task (formation flight) did not appear to be sensitive to variations in platform <span class="hlt">motion</span> condition as long as <span class="hlt">motion</span> was present. However, pilot assessment of <span class="hlt">motion</span> fidelity by means of a rating scale designed for this purpose, were sensitive to <span class="hlt">motion</span> controller design. Platform <span class="hlt">motion</span> generated with the optimal <span class="hlt">motion</span> controller was found to be generally equivalent to that generated by conventional linear crossfeed washout. The vestibular <span class="hlt">models</span> are used to evaluate the <span class="hlt">motion</span> fidelity of transport category aircraft (Boeing 727) simulation in a pilot performance and simulator acceptability study at the Man-Vehicle Systems Research Facility at NASA Ames Research Center. Eighteen airline pilots, currently flying B-727, were given a series of flight scenarios in the simulator under various conditions of simulator <span class="hlt">motion</span>. The scenarios were chosen to reflect the flight maneuvers that these pilots might expect to be given during a routine pilot proficiency check. Pilot performance and subjective rating of simulator fidelity was relatively insensitive to the <span class="hlt">motion</span> condition, despite large differences in the amplitude of <span class="hlt">motion</span> provided. This lack of sensitivity may be explained by means of the vestibular <span class="hlt">models</span>, which predict little difference in the <span class="hlt">modeled</span> <span class="hlt">motion</span> sensations of the pilots when different <span class="hlt">motion</span> conditions are imposed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=1690470','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=1690470"><span>Induced <span class="hlt">motion</span> at texture-defined <span class="hlt">motion</span> boundaries.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Johnston, A; Benton, C P; McOwan, P W</p> <p>1999-01-01</p> <p>When a static textured background is covered and uncovered by a moving bar of the same mean luminance we can clearly see the <span class="hlt">motion</span> of the bar. Texture-defined <span class="hlt">motion</span> provides an example of a naturally occurring second-order <span class="hlt">motion</span>. Second-order <span class="hlt">motion</span> sequences defeat standard spatio-temporal energy <span class="hlt">models</span> of <span class="hlt">motion</span> perception. It has been proposed that second-order stimuli are analysed by separate systems, operating in parallel with luminance-defined <span class="hlt">motion</span> processing, which incorporate identifiable pre-processing stages that make second-order patterns visible to standard techniques. However, the proposal of <span class="hlt">multiple</span> paths to <span class="hlt">motion</span> analysis remains controversial. Here we describe the behaviour of a <span class="hlt">model</span> that recovers both luminance-defined and an important class of texture-defined <span class="hlt">motion</span>. The <span class="hlt">model</span> also accounts for the induced <span class="hlt">motion</span> that is seen in some texture-defined <span class="hlt">motion</span> sequences. We measured the perceived direction and speed of both the contrast envelope and induced <span class="hlt">motion</span> in the case of a contrast modulation of static noise textures. Significantly, the <span class="hlt">model</span> predicts the perceived speed of the induced <span class="hlt">motion</span> seen at second-order texture boundaries. The induced <span class="hlt">motion</span> investigated here appears distinct from classical induced effects resulting from <span class="hlt">motion</span> contrast or the movement of a reference frame. PMID:10643088</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/23344382','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/23344382"><span>Deciphering the crowd: <span class="hlt">modeling</span> and identification of pedestrian group <span class="hlt">motion</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Yücel, Zeynep; Zanlungo, Francesco; Ikeda, Tetsushi; Miyashita, Takahiro; Hagita, Norihiro</p> <p>2013-01-14</p> <p>Associating attributes to pedestrians in a crowd is relevant for various areas like surveillance, customer profiling and service providing. The attributes of interest greatly depend on the application domain and might involve such social relations as friends or family as well as the hierarchy of the group including the leader or subordinates. Nevertheless, the complex social setting inherently complicates this task. We attack this problem by exploiting the small group structures in the crowd. The relations among individuals and their peers within a social group are reliable indicators of social attributes. To that end, this paper identifies social groups based on explicit <span class="hlt">motion</span> <span class="hlt">models</span> integrated through a hypothesis testing scheme. We develop two <span class="hlt">models</span> relating positional and directional relations. A pair of pedestrians is identified as belonging to the same group or not by utilizing the two <span class="hlt">models</span> in parallel, which defines a compound hypothesis testing scheme. By testing the proposed approach on three datasets with different environmental properties and group characteristics, it is demonstrated that we achieve an identification accuracy of 87% to 99%. The contribution of this study lies in its definition of positional and directional relation <span class="hlt">models</span>, its description of compound evaluations, and the resolution of ambiguities with our proposed uncertainty measure based on the local and global indicators of group relation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24814174','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24814174"><span>Neural population <span class="hlt">models</span> for perception of <span class="hlt">motion</span> in depth.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Peng, Qiuyan; Shi, Bertram E</p> <p>2014-08-01</p> <p>Changing disparity (CD) and interocular velocity difference (IOVD) are two possible mechanisms for stereomotion perception. We propose two neurally plausible <span class="hlt">models</span> for the representation of <span class="hlt">motion</span>-in-depth (MID) via the CD and IOVD mechanisms. These <span class="hlt">models</span> create distributed representations of MID velocity as the responses from a population of neurons selective to different MID velocity. Estimates of perceived MID velocity can be computed from the population response. They can be applied directly to binocular image sequences commonly used to characterize MID perception in psychophysical experiments. Contrary to common assumptions, we find that the CD and IOVD mechanisms cannot be distinguished easily by random dot stereograms that disrupt correlations between the two eyes or through time. We also demonstrate that the assumed spatial connectivity between the units in these <span class="hlt">models</span> can be learned through exposure to natural binocular stimuli. Our experiments with these developmental <span class="hlt">models</span> of MID selectivity suggest that neurons selective to MID are more likely to develop via the CD mechanism than the IOVD mechanism. Copyright © 2014 Elsevier B.V. All rights reserved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=john+AND+monaghan&pg=3&id=EJ615664','ERIC'); return false;" href="http://eric.ed.gov/?q=john+AND+monaghan&pg=3&id=EJ615664"><span>Algorithms, Visualization, and Mental <span class="hlt">Models</span>: High School Students' Interactions with a Relative <span class="hlt">Motion</span> Simulation.</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Monaghan, James M.; Clement, John</p> <p>2000-01-01</p> <p>Hypothesizes that the construction of visual <span class="hlt">models</span>, resolution of these visual <span class="hlt">models</span> with numeric <span class="hlt">models</span> and, in many cases, rejection of commitments such as the belief in one true velocity, are necessary for students to form integrated mental <span class="hlt">models</span> of relative <span class="hlt">motion</span> events. Studies high school students' relative <span class="hlt">motion</span> problem solving.…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016GGG....17.2408W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016GGG....17.2408W"><span>Ridge-spotting: A new test for Pacific absolute plate <span class="hlt">motion</span> <span class="hlt">models</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wessel, Paul; Müller, R. Dietmar</p> <p>2016-06-01</p> <p>Relative plate <span class="hlt">motions</span> provide high-resolution descriptions of <span class="hlt">motions</span> of plates relative to other plates. Yet geodynamically, <span class="hlt">motions</span> of plates relative to the mantle are required since such <span class="hlt">motions</span> can be attributed to forces (e.g., slab pull and ridge push) acting upon the plates. Various reference frames have been proposed, such as the hot spot reference frame, to link plate <span class="hlt">motions</span> to a mantle framework. Unfortunately, both accuracy and precision of absolute plate <span class="hlt">motion</span> <span class="hlt">models</span> lag behind those of relative plate <span class="hlt">motion</span> <span class="hlt">models</span>. Consequently, it is paramount to use relative plate <span class="hlt">motions</span> in improving our understanding of absolute plate <span class="hlt">motions</span>. A new technique called "ridge-spotting" combines absolute and relative plate <span class="hlt">motions</span> and examines the viability of proposed absolute plate <span class="hlt">motion</span> <span class="hlt">models</span>. We test the method on six published Pacific absolute plate <span class="hlt">motions</span> <span class="hlt">models</span>, including fixed and moving hot spot <span class="hlt">models</span> as well as a geodynamically derived <span class="hlt">model</span>. Ridge-spotting reconstructs the Pacific-Farallon and Pacific-Antarctica ridge systems over the last 80 Myr. All six absolute plate <span class="hlt">motion</span> <span class="hlt">models</span> predict large amounts of northward migration and monotonic clockwise rotation for the Pacific-Farallon ridge. A geodynamic implication of our ridge migration predictions is that the suggestion that the Pacific-Farallon ridge may have been pinned by a large mantle upwelling is not supported. Unexpected or erratic ridge behaviors may be tied to limitations in the <span class="hlt">models</span> themselves or (for Indo-Atlantic <span class="hlt">models</span>) discrepancies in the plate circuits used to project <span class="hlt">models</span> into the Pacific realm. Ridge-spotting is promising and will be extended to include more plates and other ocean basins.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/20849156','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/20849156"><span>Communication: Effective spectroscopic Hamiltonian for <span class="hlt">multiple</span> minima with above barrier <span class="hlt">motion</span>: Isomerization in HO(2).</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Barnes, George L; Kellman, Michael E</p> <p>2010-09-14</p> <p>We present a two-dimensional potential surface for the isomerization in the hydroperoxyl radical HO(2) and calculate the vibrational spectrum. We then show that a simple effective spectroscopic fitting Hamiltonian is capable of reproducing large scale vibrational spectral structure above the isomerization barrier. Polyad breaking with <span class="hlt">multiple</span> resonances is necessary to adequately describe the spectral features of the system. Insight into the dynamical nature of isomerization related to the effective Hamiltonian is gained through classical trajectories on the <span class="hlt">model</span> potential. Contrary to physical intuition, the bend mode is not a "reaction mode," but rather isomerization requires excitation in both stretch and bend. The dynamics reveals a Farey tree formed from the 2:1 and 3:1 resonances, corresponding to the resonance coupling terms in the effective Hamiltonian, with the prominent 5:2 (2:1+3:1) feature dividing the tree into parts that we call the 3:1 and 2:1 portions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014PhDT.........9U','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014PhDT.........9U"><span>Micro air vehicle <span class="hlt">motion</span> tracking and aerodynamic <span class="hlt">modeling</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Uhlig, Daniel V.</p> <p></p> <p> exhibited quasi-steady effects caused by small variations in the angle of attack. The quasi-steady effects, or small unsteady effects, caused variations in the aerodynamic characteristics (particularly incrementing the lift curve), and the magnitude of the influence depended on the angle-of-attack rate. In addition to nominal gliding flight, MAVs in general are capable of flying over a wide flight envelope including agile maneuvers such as perching, hovering, deep stall and maneuvering in confined spaces. From the captured <span class="hlt">motion</span> trajectories, the aerodynamic characteristics during the numerous unsteady flights were gathered without the complexity required for unsteady wind tunnel tests. Experimental results for the MAVs show large flight envelopes that included high angles of attack (on the order of 90 deg) and high angular rates, and the aerodynamic coefficients had dynamic stall hysteresis loops and large values. From the large number of unsteady high angle-of-attack flights, an aerodynamic <span class="hlt">modeling</span> method was developed and refined for unsteady MAV flight at high angles of attack. The method was based on a separation parameter that depended on the time history of the angle of attack and angle-of-attack rate. The separation parameter accounted for the time lag inherit in the longitudinal characteristics during dynamic maneuvers. The method was applied to three MAVs and showed general agreement with unsteady experimental results and with nominal gliding flight results. The flight tests with the MAVs indicate that modern <span class="hlt">motion</span> tracking systems are capable of capturing the flight trajectories, and the captured trajectories can be used to determine the aerodynamic characteristics. From the captured trajectories, low Reynolds number MAV flight is explored in both nominal gliding flight and unsteady high angle-of-attack flight. Building on the experimental results, a <span class="hlt">modeling</span> method for the longitudinal characteristics is developed that is applicable to the full flight</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016PhBio..13a6006L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016PhBio..13a6006L"><span><span class="hlt">Modeling</span> closure of circular wounds through coordinated collective <span class="hlt">motion</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Li, David S.; Zimmermann, Juliane; Levine, Herbert</p> <p>2016-02-01</p> <p>Wound healing enables tissues to restore their original states, and is achieved through collective cell migration into the wound space, contraction of the wound edge via an actomyosin filament ‘purse-string,’ as well as cell division. Recently, experimental techniques have been developed to create wounds with various regular morphologies in epithelial monolayers, and these experiments of circular closed-contour wounds support coordinated lamellipodial cell crawling as the predominant driver of gap closure. Through utilizing a particle-based mechanical tissue simulation, exhibiting long-range coordination of cell motility, we computationally <span class="hlt">model</span> these closed-contour experiments with a high level of agreement between experimentally observed and simulated wound closure dynamics and tissue velocity profiles. We also determine the sensitivity of wound closure time in the <span class="hlt">model</span> to changes in cell motility force and division rate. Our simulation results confirm that circular wounds can close due to collective cell migration without the necessity for a purse-string mechanism or for cell division, and show that the alignment mechanism of cellular motility force with velocity, leading to collective <span class="hlt">motion</span> in the <span class="hlt">model</span>, may speed up wound closure.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li class="active"><span>14</span></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_14 --> <div id="page_15" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li class="active"><span>15</span></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="281"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1084203','DOE-PATENT-XML'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1084203"><span>Detecting <span class="hlt">multiple</span> moving objects in crowded environments with coherent <span class="hlt">motion</span> regions</span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Cheriyadat, Anil M.; Radke, Richard J.</p> <p>2013-06-11</p> <p>Coherent <span class="hlt">motion</span> regions extend in time as well as space, enforcing consistency in detected objects over long time periods and making the algorithm robust to noisy or short point tracks. As a result of enforcing the constraint that selected coherent <span class="hlt">motion</span> regions contain disjoint sets of tracks defined in a three-dimensional space including a time dimension. An algorithm operates directly on raw, unconditioned low-level feature point tracks, and minimizes a global measure of the coherent <span class="hlt">motion</span> regions. At least one discrete moving object is identified in a time series of video images based on the trajectory similarity factors, which is a measure of a maximum distance between a pair of feature point tracks.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..18.2063L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..18.2063L"><span>Synthetic ground-<span class="hlt">motion</span> simulation using a spatial stochastic <span class="hlt">model</span> with slip self-similarity: Toward near-source ground-<span class="hlt">motion</span> validation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lee, Ya-Ting; Ma, Kuo-Fong; Hsieh, Ming-Che; Yen, Yin-Tung; Sun, Yu-Sheng</p> <p>2016-04-01</p> <p>Near-fault ground <span class="hlt">motion</span> is a key to understand the seismic hazard along the fault, and is a challenge by the approach of ground <span class="hlt">motion</span> prediction equation. This paper presents a developed stochastic-slip-scaling source <span class="hlt">model</span>, a spatial stochastic <span class="hlt">model</span> with slip scaling of the slipped area, toward ground <span class="hlt">motion</span> simulation. We considered the near-fault ground <span class="hlt">motion</span> of the 1999 Chi-Chi earthquake (Mw 7.7) in Taiwan, which having the most massive near-fault data of a disaster earthquake, as a reference for validation. Including the developed stochastic-slip-scaling source <span class="hlt">model</span>, two scenario source <span class="hlt">models</span>, mean-slip <span class="hlt">model</span>, characteristic-asperity <span class="hlt">model</span> were also used for the examination on the near-fault ground <span class="hlt">motion</span>. We simulated synthetic ground <span class="hlt">motion</span> through 3D waveforms and validated these simulations by using observed data and the ground-<span class="hlt">motion</span> prediction equation (GMPE) for Taiwan earthquakes. The mean slip and characteristic asperity scenario source <span class="hlt">models</span> over-predicted the near-fault ground <span class="hlt">motion</span>. The stochastic-slip-scaling <span class="hlt">model</span> proposed in this paper is more accurately approximated to the near-fault <span class="hlt">motion</span> compared with the GMPE and observations. This is the first study to incorporate slipped-area scaling in a stochastic slip <span class="hlt">model</span>. The proposed <span class="hlt">model</span> can generate scenario earthquakes for predicting ground <span class="hlt">motion</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70036311','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70036311"><span>Ground-<span class="hlt">motion</span> <span class="hlt">modeling</span> of Hayward fault scenario earthquakes, part II: Simulation of long-period and broadband ground <span class="hlt">motions</span></span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Aagaard, Brad T.; Graves, Robert W.; Rodgers, Arthur; Brocher, Thomas M.; Simpson, Robert W.; Dreger, Douglas; Petersson, N. Anders; Larsen, Shawn C.; Ma, Shuo; Jachens, Robert C.</p> <p>2010-01-01</p> <p>We simulate long-period (T>1.0–2.0 s) and broadband (T>0.1 s) ground <span class="hlt">motions</span> for 39 scenario earthquakes (Mw 6.7–7.2) involving the Hayward, Calaveras, and Rodgers Creek faults. For rupture on the Hayward fault, we consider the effects of creep on coseismic slip using two different approaches, both of which reduce the ground <span class="hlt">motions</span>, compared with neglecting the influence of creep. Nevertheless, the scenario earthquakes generate strong shaking throughout the San Francisco Bay area, with about 50% of the urban area experiencing modified Mercalli intensity VII or greater for the magnitude 7.0 scenario events. Long-period simulations of the 2007 Mw 4.18 Oakland earthquake and the 2007 Mw 5.45 Alum Rock earthquake show that the U.S. Geological Survey’s Bay Area Velocity <span class="hlt">Model</span> version 08.3.0 permits simulation of the amplitude and duration of shaking throughout the San Francisco Bay area for Hayward fault earthquakes, with the greatest accuracy in the Santa Clara Valley (San Jose area). The ground <span class="hlt">motions</span> for the suite of scenarios exhibit a strong sensitivity to the rupture length (or magnitude), hypocenter (or rupture directivity), and slip distribution. The ground <span class="hlt">motions</span> display a much weaker sensitivity to the rise time and rupture speed. Peak velocities, peak accelerations, and spectral accelerations from the synthetic broadband ground <span class="hlt">motions</span> are, on average, slightly higher than the Next Generation Attenuation (NGA) ground-<span class="hlt">motion</span> prediction equations. We attribute much of this difference to the seismic velocity structure in the San Francisco Bay area and how the NGA <span class="hlt">models</span> account for basin amplification; the NGA relations may underpredict amplification in shallow sedimentary basins. The simulations also suggest that the Spudich and Chiou (2008) directivity corrections to the NGA relations could be improved by increasing the areal extent of rupture directivity with period.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=LMA&id=EJ766721','ERIC'); return false;" href="http://eric.ed.gov/?q=LMA&id=EJ766721"><span>Log-<span class="hlt">Multiplicative</span> Association <span class="hlt">Models</span> as Item Response <span class="hlt">Models</span></span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Anderson, Carolyn J.; Yu, Hsiu-Ting</p> <p>2007-01-01</p> <p>Log-<span class="hlt">multiplicative</span> association (LMA) <span class="hlt">models</span>, which are special cases of log-linear <span class="hlt">models</span>, have interpretations in terms of latent continuous variables. Two theoretical derivations of LMA <span class="hlt">models</span> based on item response theory (IRT) arguments are presented. First, we show that Anderson and colleagues (Anderson & Vermunt, 2000; Anderson & Bockenholt,…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/6479679','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/6479679"><span>Double <span class="hlt">multiple</span> streamtube <span class="hlt">model</span> with recent improvements</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Paraschivoiu, I.; Delclaux, F.</p> <p>1983-05-01</p> <p>The objective of the present paper is to show the new capabilities of the double <span class="hlt">multiple</span> streamtube (DMS) <span class="hlt">model</span> for predicting the aerodynamic loads and performance of the Darrieus vertical-axis turbine. The original DMS <span class="hlt">model</span> has been improved (DMSV <span class="hlt">model</span>) by considering the variation in the upwind and downwind induced velocities as a function of the azimuthal angle for each streamtube. A comparison is made of the rotor performance for several blade geometries (parabola, catenary, troposkien, and Sandia shape). A new formulation is given for an approximate troposkien shape by considering the effect of the gravitational field. The effects of three NACA symmetrical profiles, 0012, 0015 and 0018, on the aerodynamic performance of the turbine are shown. Finally, a semiempirical dynamic-stall <span class="hlt">model</span> has been incorporated and a better approximation obtained for <span class="hlt">modeling</span> the local aerodynamic forces and performance for a Darrieus rotor.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/6857303','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/6857303"><span>Double <span class="hlt">multiple</span> streamtube <span class="hlt">model</span> with recent improvements</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Paraschivoiu, I.; Delclaux, F.</p> <p>1983-05-01</p> <p>The objective is to show the new capabilities of the double <span class="hlt">multiple</span> streamtube (DMS) <span class="hlt">model</span> for predicting the aerodynamic loads and performance of the Darrieus vertical-axis turbine. The original DMS <span class="hlt">model</span> has been improved (DMSV <span class="hlt">model</span>) by considering the variation in the upwind and downwind induced velocities as a function of the azimuthal angle for each streamtube. A comparison is made of the rotor performance for several blade geometries (parabola, catenary, troposkien, and Sandia shape). A new formulation is given for an approximate troposkien shape by considering the effect of the gravitational field. The effects of three NACA symmetrical profiles, 0012, 0015 and 0018, on the aerodynamic performance of the turbine are shown. Finally, a semiempirical dynamic-stall <span class="hlt">model</span> has been incorporated and a better approximation obtained for <span class="hlt">modeling</span> the local aerodynamic forces and performance for a Darrieus rotor.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017NatSR...745770Q','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017NatSR...745770Q"><span><span class="hlt">Modeling</span> of coupled <span class="hlt">motion</span> and growth interaction of equiaxed dendritic crystals in a binary alloy during solidification</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Qi, Xin Bo; Chen, Yun; Kang, Xiu Hong; Li, Dian Zhong; Gong, Tong Zhao</p> <p>2017-03-01</p> <p><span class="hlt">Motion</span> of growing dendrites is a common phenomenon during solidification but often neglected in numerical simulations because of the complicate underlying multiphysics. Here a phase-field <span class="hlt">model</span> incorporating dendrite-melt two-phase flow is proposed for simulating the dynamically interacted process. The proposed <span class="hlt">model</span> circumvents complexity to resolve dendritic growth, natural convection and solid <span class="hlt">motion</span> simultaneously. Simulations are performed for single and <span class="hlt">multiple</span> dendritic growth of an Al-based alloy in a gravity environment. Computing results of an isolated dendrite settling down in the convective supersaturated melt shows that solid <span class="hlt">motion</span> is able to overwhelm solutal convection and causes a rather different growth morphology from the stationary dendrite that considers natural convection alone. The simulated tip growth dynamics are correlated with a modified boundary layer <span class="hlt">model</span> in the presence of melt flow, which well accounts for the variation of tip velocity with flow direction. Polycrystalline simulations reveal that the <span class="hlt">motion</span> of dendrites accelerates the occurrence of growth impingement which causes the behaviors of <span class="hlt">multiple</span> dendrites are distinct from that of single dendrite, including growth dynamics, morphology evolution and movement path. These polycrystalline simulations provide a primary understanding of the sedimentation of crystals and resulting chemical homogeneity in industrial ingots.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5374713','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5374713"><span><span class="hlt">Modeling</span> of coupled <span class="hlt">motion</span> and growth interaction of equiaxed dendritic crystals in a binary alloy during solidification</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Qi, Xin Bo; Chen, Yun; Kang, Xiu Hong; Li, Dian Zhong; Gong, Tong Zhao</p> <p>2017-01-01</p> <p><span class="hlt">Motion</span> of growing dendrites is a common phenomenon during solidification but often neglected in numerical simulations because of the complicate underlying multiphysics. Here a phase-field <span class="hlt">model</span> incorporating dendrite-melt two-phase flow is proposed for simulating the dynamically interacted process. The proposed <span class="hlt">model</span> circumvents complexity to resolve dendritic growth, natural convection and solid <span class="hlt">motion</span> simultaneously. Simulations are performed for single and <span class="hlt">multiple</span> dendritic growth of an Al-based alloy in a gravity environment. Computing results of an isolated dendrite settling down in the convective supersaturated melt shows that solid <span class="hlt">motion</span> is able to overwhelm solutal convection and causes a rather different growth morphology from the stationary dendrite that considers natural convection alone. The simulated tip growth dynamics are correlated with a modified boundary layer <span class="hlt">model</span> in the presence of melt flow, which well accounts for the variation of tip velocity with flow direction. Polycrystalline simulations reveal that the <span class="hlt">motion</span> of dendrites accelerates the occurrence of growth impingement which causes the behaviors of <span class="hlt">multiple</span> dendrites are distinct from that of single dendrite, including growth dynamics, morphology evolution and movement path. These polycrystalline simulations provide a primary understanding of the sedimentation of crystals and resulting chemical homogeneity in industrial ingots. PMID:28361933</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28361933','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28361933"><span><span class="hlt">Modeling</span> of coupled <span class="hlt">motion</span> and growth interaction of equiaxed dendritic crystals in a binary alloy during solidification.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Qi, Xin Bo; Chen, Yun; Kang, Xiu Hong; Li, Dian Zhong; Gong, Tong Zhao</p> <p>2017-03-31</p> <p><span class="hlt">Motion</span> of growing dendrites is a common phenomenon during solidification but often neglected in numerical simulations because of the complicate underlying multiphysics. Here a phase-field <span class="hlt">model</span> incorporating dendrite-melt two-phase flow is proposed for simulating the dynamically interacted process. The proposed <span class="hlt">model</span> circumvents complexity to resolve dendritic growth, natural convection and solid <span class="hlt">motion</span> simultaneously. Simulations are performed for single and <span class="hlt">multiple</span> dendritic growth of an Al-based alloy in a gravity environment. Computing results of an isolated dendrite settling down in the convective supersaturated melt shows that solid <span class="hlt">motion</span> is able to overwhelm solutal convection and causes a rather different growth morphology from the stationary dendrite that considers natural convection alone. The simulated tip growth dynamics are correlated with a modified boundary layer <span class="hlt">model</span> in the presence of melt flow, which well accounts for the variation of tip velocity with flow direction. Polycrystalline simulations reveal that the <span class="hlt">motion</span> of dendrites accelerates the occurrence of growth impingement which causes the behaviors of <span class="hlt">multiple</span> dendrites are distinct from that of single dendrite, including growth dynamics, morphology evolution and movement path. These polycrystalline simulations provide a primary understanding of the sedimentation of crystals and resulting chemical homogeneity in industrial ingots.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014JGeod..88.1117L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014JGeod..88.1117L"><span>Transformation <span class="hlt">model</span> selection by <span class="hlt">multiple</span> hypotheses testing</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lehmann, Rüdiger</p> <p>2014-12-01</p> <p>Transformations between different geodetic reference frames are often performed such that first the transformation parameters are determined from control points. If in the first place we do not know which of the numerous transformation <span class="hlt">models</span> is appropriate then we can set up a <span class="hlt">multiple</span> hypotheses test. The paper extends the common method of testing transformation parameters for significance, to the case that also constraints for such parameters are tested. This provides more flexibility when setting up such a test. One can formulate a general <span class="hlt">model</span> with a maximum number of transformation parameters and specialize it by adding constraints to those parameters, which need to be tested. The proper test statistic in a <span class="hlt">multiple</span> test is shown to be either the extreme normalized or the extreme studentized Lagrange multiplier. They are shown to perform superior to the more intuitive test statistics derived from misclosures. It is shown how <span class="hlt">model</span> selection by <span class="hlt">multiple</span> hypotheses testing relates to the use of information criteria like AICc and Mallows' , which are based on an information theoretic approach. Nevertheless, whenever comparable, the results of an exemplary computation almost coincide.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=force+AND+motion&pg=4&id=EJ860246','ERIC'); return false;" href="http://eric.ed.gov/?q=force+AND+motion&pg=4&id=EJ860246"><span>Demonstrating Circular <span class="hlt">Motion</span> with a <span class="hlt">Model</span> Satellite/Earth System</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Whittaker, Jeff</p> <p>2008-01-01</p> <p>A number of interesting demonstrations of circular and satellite <span class="hlt">motion</span> have been described in this journal. This paper presents a variation of a centripetal force apparatus found in G.D. Freier and F.J. Anderson's "A Demonstration Handbook for Physics," which has been modified in order to demonstrate both centripetal force and satellite <span class="hlt">motion</span>.…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://eric.ed.gov/?q=satellite+AND+handbook&id=EJ860246','ERIC'); return false;" href="https://eric.ed.gov/?q=satellite+AND+handbook&id=EJ860246"><span>Demonstrating Circular <span class="hlt">Motion</span> with a <span class="hlt">Model</span> Satellite/Earth System</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Whittaker, Jeff</p> <p>2008-01-01</p> <p>A number of interesting demonstrations of circular and satellite <span class="hlt">motion</span> have been described in this journal. This paper presents a variation of a centripetal force apparatus found in G.D. Freier and F.J. Anderson's "A Demonstration Handbook for Physics," which has been modified in order to demonstrate both centripetal force and satellite <span class="hlt">motion</span>.…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011SPIE.8205E..2UX','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011SPIE.8205E..2UX"><span>A novel body <span class="hlt">motion</span> <span class="hlt">model</span> based personal dead-reckoning system</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Xiang, Zhiyu; Qi, Baozhen; Wang, Jiafeng</p> <p>2011-10-01</p> <p>This paper presents a novel human body <span class="hlt">motion</span> <span class="hlt">model</span> based dead reckoning approach. After brief description of system overview, a new body <span class="hlt">motion</span> <span class="hlt">model</span> is given based on the inherent relationship between step frequency and step length existed in two common <span class="hlt">motion</span> patterns: walking and running. The parameter calibration of the <span class="hlt">model</span> is given as well. Upon receiving the data from sensors, step frequency is first computed by detecting the periodic changing of linear acceleration in vertical axis, and then the real-time footstep length can be obtained according to the proposed <span class="hlt">motion</span> <span class="hlt">model</span>. Angular velocity measurement produced by vertical gyroscope is filtered and integrated by Kalman filter to obtain <span class="hlt">motion</span> direction change. With movement distance and direction in hand, dead-reckoning can be easily carried out. Experimental results based on real data acquired under different <span class="hlt">motion</span> patterns show the promising performance of the system.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26595904','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26595904"><span>Feasibility Study of Respiratory <span class="hlt">Motion</span> <span class="hlt">Modeling</span> Based Correction for MRI-Guided Intracardiac Interventional Procedures.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Xu, Robert; Athavale, Prashant; Krahn, Philippa; Anderson, Kevan; Barry, Jennifer; Biswas, Labonny; Ramanan, Venkat; Yak, Nicolas; Pop, Mihaela; Wright, Graham A</p> <p>2015-12-01</p> <p>The purpose of this study is to improve the accuracy of interventional catheter guidance during intracardiac procedures. Specifically, the use of preprocedural magnetic resonance roadmap images for interventional guidance has limited anatomical accuracy due to intraprocedural respiratory <span class="hlt">motion</span> of the heart. Therefore, we propose to build a novel respiratory <span class="hlt">motion</span> <span class="hlt">model</span> to compensate for this <span class="hlt">motion</span>-induced error during magnetic resonance imaging (MRI)-guided procedures. We acquire 2-D real-time free-breathing images to characterize the respiratory <span class="hlt">motion</span>, and build a smooth <span class="hlt">motion</span> <span class="hlt">model</span> via registration of 3-D prior roadmap images to the real-time images within a novel principal axes frame of reference. The <span class="hlt">model</span> is subsequently used to correct the interventional catheter positions with respect to the anatomy of the heart. We demonstrate that the proposed <span class="hlt">modeling</span> framework can lead to smoother <span class="hlt">motion</span> <span class="hlt">models</span>, and potentially lead to more accurate <span class="hlt">motion</span> estimates. Specifically, MRI-guided intracardiac ablations were performed in six preclinical animal experiments. Then, from retrospective analysis, the proposed <span class="hlt">motion</span> <span class="hlt">modeling</span> technique showed the potential to achieve a 27% improvement in ablation targeting accuracy. The feasibility of a respiratory <span class="hlt">motion</span> <span class="hlt">model</span>-based correction framework has been successfully demonstrated. The improvement in ablation accuracy may lead to significant improvements in success rate and patient outcomes for MRI-guided intracardiac procedures.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1020341','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1020341"><span>Ground <span class="hlt">motion</span> <span class="hlt">modeling</span> of Hayward fault scenario earthquakes II:Simulation of long-period and broadband ground <span class="hlt">motions</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Aagaard, B T; Graves, R W; Rodgers, A; Brocher, T M; Simpson, R W; Dreger, D; Petersson, N A; Larsen, S C; Ma, S; Jachens, R C</p> <p>2009-11-04</p> <p>We simulate long-period (T > 1.0-2.0 s) and broadband (T > 0.1 s) ground <span class="hlt">motions</span> for 39 scenarios earthquakes (Mw 6.7-7.2) involving the Hayward, Calaveras, and Rodgers Creek faults. For rupture on the Hayward fault we consider the effects of creep on coseismic slip using two different approaches, both of which reduce the ground <span class="hlt">motions</span> compared with neglecting the influence of creep. Nevertheless, the scenario earthquakes generate strong shaking throughout the San Francisco Bay area with about 50% of the urban area experiencing MMI VII or greater for the magnitude 7.0 scenario events. Long-period simulations of the 2007 Mw 4.18 Oakland and 2007 Mw 4.5 Alum Rock earthquakes show that the USGS Bay Area Velocity <span class="hlt">Model</span> version 08.3.0 permits simulation of the amplitude and duration of shaking throughout the San Francisco Bay area, with the greatest accuracy in the Santa Clara Valley (San Jose area). The ground <span class="hlt">motions</span> exhibit a strong sensitivity to the rupture length (or magnitude), hypocenter (or rupture directivity), and slip distribution. The ground <span class="hlt">motions</span> display a much weaker sensitivity to the rise time and rupture speed. Peak velocities, peak accelerations, and spectral accelerations from the synthetic broadband ground <span class="hlt">motions</span> are, on average, slightly higher than the Next Generation Attenuation (NGA) ground-<span class="hlt">motion</span> prediction equations. We attribute at least some of this difference to the relatively narrow width of the Hayward fault ruptures. The simulations suggest that the Spudich and Chiou (2008) directivity corrections to the NGA relations could be improved by including a dependence on the rupture speed and increasing the areal extent of rupture directivity with period. The simulations also indicate that the NGA relations may under-predict amplification in shallow sedimentary basins.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/17664554','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/17664554"><span>Dual-component <span class="hlt">model</span> of respiratory <span class="hlt">motion</span> based on the periodic autoregressive moving average (periodic ARMA) method.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>McCall, K C; Jeraj, R</p> <p>2007-06-21</p> <p>A new approach to the problem of <span class="hlt">modelling</span> and predicting respiration <span class="hlt">motion</span> has been implemented. This is a dual-component <span class="hlt">model</span>, which describes the respiration <span class="hlt">motion</span> as a non-periodic time series superimposed onto a periodic waveform. A periodic autoregressive moving average algorithm has been used to define a mathematical <span class="hlt">model</span> of the periodic and non-periodic components of the respiration <span class="hlt">motion</span>. The periodic components of the <span class="hlt">motion</span> were found by projecting <span class="hlt">multiple</span> inhale-exhale cycles onto a common subspace. The component of the respiration signal that is left after removing this periodicity is a partially autocorrelated time series and was <span class="hlt">modelled</span> as an autoregressive moving average (ARMA) process. The accuracy of the periodic ARMA <span class="hlt">model</span> with respect to fluctuation in amplitude and variation in length of cycles has been assessed. A respiration phantom was developed to simulate the inter-cycle variations seen in free-breathing and coached respiration patterns. At +/-14% variability in cycle length and maximum amplitude of <span class="hlt">motion</span>, the prediction errors were 4.8% of the total <span class="hlt">motion</span> extent for a 0.5 s ahead prediction, and 9.4% at 1.0 s lag. The prediction errors increased to 11.6% at 0.5 s and 21.6% at 1.0 s when the respiration pattern had +/-34% variations in both these parameters. Our results have shown that the accuracy of the periodic ARMA <span class="hlt">model</span> is more strongly dependent on the variations in cycle length than the amplitude of the respiration cycles.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007PMB....52.3455M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007PMB....52.3455M"><span>Dual-component <span class="hlt">model</span> of respiratory <span class="hlt">motion</span> based on the periodic autoregressive moving average (periodic ARMA) method</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>McCall, K. C.; Jeraj, R.</p> <p>2007-07-01</p> <p>A new approach to the problem of <span class="hlt">modelling</span> and predicting respiration <span class="hlt">motion</span> has been implemented. This is a dual-component <span class="hlt">model</span>, which describes the respiration <span class="hlt">motion</span> as a non-periodic time series superimposed onto a periodic waveform. A periodic autoregressive moving average algorithm has been used to define a mathematical <span class="hlt">model</span> of the periodic and non-periodic components of the respiration <span class="hlt">motion</span>. The periodic components of the <span class="hlt">motion</span> were found by projecting <span class="hlt">multiple</span> inhale-exhale cycles onto a common subspace. The component of the respiration signal that is left after removing this periodicity is a partially autocorrelated time series and was <span class="hlt">modelled</span> as an autoregressive moving average (ARMA) process. The accuracy of the periodic ARMA <span class="hlt">model</span> with respect to fluctuation in amplitude and variation in length of cycles has been assessed. A respiration phantom was developed to simulate the inter-cycle variations seen in free-breathing and coached respiration patterns. At ±14% variability in cycle length and maximum amplitude of <span class="hlt">motion</span>, the prediction errors were 4.8% of the total <span class="hlt">motion</span> extent for a 0.5 s ahead prediction, and 9.4% at 1.0 s lag. The prediction errors increased to 11.6% at 0.5 s and 21.6% at 1.0 s when the respiration pattern had ±34% variations in both these parameters. Our results have shown that the accuracy of the periodic ARMA <span class="hlt">model</span> is more strongly dependent on the variations in cycle length than the amplitude of the respiration cycles.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/10899198','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/10899198"><span>Apparent <span class="hlt">motion</span> produces <span class="hlt">multiple</span> deficits in visually guided smooth pursuit eye movements of monkeys.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Churchland, M M; Lisberger, S G</p> <p>2000-07-01</p> <p>We used apparent <span class="hlt">motion</span> targets to explore how degraded visual <span class="hlt">motion</span> alters smooth pursuit eye movements. Apparent <span class="hlt">motion</span> targets consisted of brief stationary flashes with a spatial separation (Deltax), temporal separation (Deltat), and apparent target velocity equal to Deltax/Deltat. Changes in pursuit initiation were readily observed when holding target velocity constant and increasing the flash separation. As flash separation increased, the first deficit observed was an increase in the latency to peak eye acceleration. Also seen was a paradoxical increase in initial eye acceleration. Further increases in the flash separation produced larger increases in latency and resulted in decreased eye acceleration. By varying target velocity, we were able to discern that the visual inputs driving pursuit initiation show both temporal and spatial limits. For target velocities above 4-8 degrees /s, deficits in the initiation of pursuit were seen when Deltax exceeded 0.2-0.5 degrees, even when Deltat was small. For target velocities below 4-8 degrees /s, deficits appeared when Deltat exceeded 32-64 ms, even when Deltax was small. Further experiments were designed to determine whether the spatial limit varied as retinal and extra-retinal factors changed. Varying the initial retinal position of the target for <span class="hlt">motion</span> at 18 degrees /s revealed that the spatial limit increased as a function of retinal eccentricity. We then employed targets that increased velocity twice, once from fixation and again during pursuit. These experiments revealed that, as expected, the spatial limit is expressed in terms of the flash separation on the retina. The spatial limit is uninfluenced by either eye velocity or the absolute velocity of the target. These experiments also demonstrate that "initiation" deficits can be observed during ongoing pursuit, and are thus not deficits in initiation per se. We conclude that such deficits result from degradation of the retino-centric <span class="hlt">motion</span> signals that</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016SPIE.9797E..0YL','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016SPIE.9797E..0YL"><span>A soft biomimetic tongue: <span class="hlt">model</span> reconstruction and <span class="hlt">motion</span> tracking</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lu, Xuanming; Xu, Weiliang; Li, Xiaoning</p> <p>2016-04-01</p> <p>A bioinspired robotic tongue which is actuated by a network of compressed air is proposed for the purpose of mimicking the movements of human tongue. It can be applied in the fields such as medical science and food engineering. The robotic tongue is made of two kinds of silicone rubber Ecoflex 0030 and PDMS with the shape simplified from real human tongue. In order to characterize the robotic tongue, a series of experiments were carried out. Laser scan was applied to reconstruct the static <span class="hlt">model</span> of robotic tongue when it was under pressurization. After each scan, the robotic tongue was scattered into dense points in the same 3D coordinate system and the coordinates of each point were recorded. <span class="hlt">Motion</span> tracking system (OptiTrack) was used to track and record the whole process of deformation dynamically during the loading and unloading phase. In the experiments, five types of deformation were achieved including roll-up, roll-down, elongation, groove and twist. Utilizing the discrete points generated by laser scan, the accurate parameterized outline of robotic tongue under different pressure was obtained, which could help demonstrate the static characteristic of robotic tongue. The precise deformation process under one pressure was acquired through the OptiTrack system which contains a series of digital cameras, markers on the robotic tongue and a set of hardware and software for data processing. By means of tracking and recording different process of deformation under different pressure, the dynamic characteristic of robotic tongue could be achieved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.dtic.mil/docs/citations/ADA617753','DTIC-ST'); return false;" href="http://www.dtic.mil/docs/citations/ADA617753"><span><span class="hlt">Multiple</span> Kernel Learning for Vehicle Detection in Wide Area <span class="hlt">Motion</span> Imagery</span></a></p> <p><a target="_blank" href="http://www.dtic.mil/">DTIC Science & Technology</a></p> <p></p> <p>2012-07-01</p> <p>temple.edu, erik.blasch@gmail.com, genshe.chen@ieee.org Abstract —Vehicle detection in wide area <span class="hlt">motion</span> imagery (WAMI) is an important problem in computer...in Sinapore on 9-12 July 2012. Sponsored in part by Office of Naval Research and Office of Naval Research Global. 14. ABSTRACT Vehicle detection in...outperforms the other three classification schemes. 15. SUBJECT TERMS 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT Same as Report</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li class="active"><span>15</span></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_15 --> <div id="page_16" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li class="active"><span>16</span></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="301"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009EJASP2010..209C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009EJASP2010..209C"><span>Analysis and <span class="hlt">Modelling</span> of Muscles <span class="hlt">Motion</span> during Whole Body Vibration</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Cesarelli, M.; Fratini, A.; Bifulco, P.; La Gatta, A.; Romano, M.; Pasquariello, G.</p> <p>2009-12-01</p> <p>The aim of the study is to characterize the local muscles <span class="hlt">motion</span> in individuals undergoing whole body mechanical stimulation. In this study we aim also to evaluate how subject positioning modifies vibration dumping, altering local mechanical stimulus. Vibrations were delivered to subjects by the use of a vibrating platform, while stimulation frequency was increased linearly from 15 to 60 Hz. Two different subject postures were here analysed. Platform and muscles <span class="hlt">motion</span> were monitored using tiny MEMS accelerometers; a contra lateral analysis was also presented. Muscle <span class="hlt">motion</span> analysis revealed typical displacement trajectories: <span class="hlt">motion</span> components were found not to be purely sinusoidal neither in phase to each other. Results also revealed a mechanical resonant-like behaviour at some muscles, similar to a second-order system response. Resonance frequencies and dumping factors depended on subject and his positioning. Proper mechanical stimulation can maximize muscle spindle solicitation, which may produce a more effective muscle activation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.dtic.mil/docs/citations/ADA202770','DTIC-ST'); return false;" href="http://www.dtic.mil/docs/citations/ADA202770"><span>A Study of <span class="hlt">Motion</span> Sickness: Mathematical <span class="hlt">Modeling</span> and Data Analysis</span></a></p> <p><a target="_blank" href="http://www.dtic.mil/">DTIC Science & Technology</a></p> <p></p> <p>1988-12-01</p> <p>Warwick-Evans, L.A. and others. " Electrodermal Activity as an Index of <span class="hlt">Motion</span> Sickness," Aviation, Space, and Environmental Medicine, 58: 417-423 (May...have recorded EEG activity which appears to specif- ically accompany <span class="hlt">motion</span> sickness. In 1986, Hartle, McPherson, and Miller reported "distinctive...change sim- *ilar to that reported a year earlier (17:30). Gaudreault hypothesized that the low frequency brain wave activity was due to</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19770047058&hterms=Harmonic+motion&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3DHarmonic%2Bmotion','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19770047058&hterms=Harmonic+motion&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3DHarmonic%2Bmotion"><span>Unsteady aerodynamic <span class="hlt">modeling</span> for arbitrary <span class="hlt">motions</span>. [for active control techniques</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Edwards, J. W.</p> <p>1977-01-01</p> <p>Results indicating that unsteady aerodynamic loads derived under the assumption of simple harmonic <span class="hlt">motions</span> executed by airfoil or wing can be extended to arbitrary <span class="hlt">motions</span> are summarized. The generalized Theodorsen (1953) function referable to loads due to simple harmonic oscillations of a wing section in incompressible flow, the Laplace inversion integral for unsteady aerodynamic loads, calculations of root loci of aeroelastic loads, and analysis of generalized compressible transient airloads are discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27745981','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27745981"><span>A Novel Respiratory <span class="hlt">Motion</span> Perturbation <span class="hlt">Model</span> Adaptable to Patient Breathing Irregularities.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Yuan, Amy; Wei, Jie; Gaebler, Carl P; Huang, Hailiang; Olek, Devin; Li, Guang</p> <p>2016-12-01</p> <p>To develop a physical, adaptive <span class="hlt">motion</span> perturbation <span class="hlt">model</span> to predict tumor <span class="hlt">motion</span> using feedback from dynamic measurement of breathing conditions to compensate for breathing irregularities. A novel respiratory <span class="hlt">motion</span> perturbation (RMP) <span class="hlt">model</span> was developed to predict tumor <span class="hlt">motion</span> variations caused by breathing irregularities. This <span class="hlt">model</span> contained 2 terms: the initial tumor <span class="hlt">motion</span> trajectory, measured from 4-dimensional computed tomography (4DCT) images, and <span class="hlt">motion</span> perturbation, calculated from breathing variations in tidal volume (TV) and breathing pattern (BP). The <span class="hlt">motion</span> perturbation was derived from the patient-specific anatomy, tumor-specific location, and time-dependent breathing variations. Ten patients were studied, and 2 amplitude-binned 4DCT images for each patient were acquired within 2 weeks. The <span class="hlt">motion</span> trajectories of 40 corresponding bifurcation points in both 4DCT images of each patient were obtained using deformable image registration. An in-house 4D data processing toolbox was developed to calculate the TV and BP as functions of the breathing phase. The <span class="hlt">motion</span> was predicted from the simulation 4DCT scan to the treatment 4DCT scan, and vice versa, resulting in 800 predictions. For comparison, noncorrected <span class="hlt">motion</span> differences and the predictions from a published 5-dimensional <span class="hlt">model</span> were used. The average <span class="hlt">motion</span> range in the superoinferior direction was 9.4 ± 4.4 mm, the average ΔTV ranged from 10 to 248 mm(3) (-26% to 61%), and the ΔBP ranged from 0 to 0.2 (-71% to 333%) between the 2 4DCT scans. The mean noncorrected <span class="hlt">motion</span> difference was 2.0 ± 2.8 mm between 2 4DCT <span class="hlt">motion</span> trajectories. After applying the RMP <span class="hlt">model</span>, the mean <span class="hlt">motion</span> difference was reduced significantly to 1.2 ± 1.8 mm (P=.0018), a 40% improvement, similar to the 1.2 ± 1.8 mm (P=.72) predicted with the 5-dimensional <span class="hlt">model</span>. A novel physical RMP <span class="hlt">model</span> was developed with an average accuracy of 1.2 ± 1.8 mm for interfraction <span class="hlt">motion</span> prediction, similar to that of a</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26176412','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26176412"><span>Analytic signal phase-based myocardial <span class="hlt">motion</span> estimation in tagged MRI sequences by a bilinear <span class="hlt">model</span> and <span class="hlt">motion</span> compensation.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Wang, Liang; Basarab, Adrian; Girard, Patrick R; Croisille, Pierre; Clarysse, Patrick; Delachartre, Philippe</p> <p>2015-08-01</p> <p>Different mathematical tools, such as multidimensional analytic signals, allow for the calculation of 2D spatial phases of real-value images. The <span class="hlt">motion</span> estimation method proposed in this paper is based on two spatial phases of the 2D analytic signal applied to cardiac sequences. By combining the information of these phases issued from analytic signals of two successive frames, we propose an analytical estimator for 2D local displacements. To improve the accuracy of the <span class="hlt">motion</span> estimation, a local bilinear deformation <span class="hlt">model</span> is used within an iterative estimation scheme. The main advantages of our method are: (1) The phase-based method allows the displacement to be estimated with subpixel accuracy and is robust to image intensity variation in time; (2) Preliminary filtering is not required due to the bilinear <span class="hlt">model</span>. The proposed algorithm, integrating phase-based optical flow <span class="hlt">motion</span> estimation and the combination of global <span class="hlt">motion</span> compensation with local bilinear transform, allows spatio-temporal cardiac <span class="hlt">motion</span> analysis, e.g. strain and dense trajectory estimation over the cardiac cycle. Results from 7 realistic simulated tagged magnetic resonance imaging (MRI) sequences show that our method is more accurate compared with state-of-the-art method for cardiac <span class="hlt">motion</span> analysis and with another differential approach from the literature. The <span class="hlt">motion</span> estimation errors (end point error) of the proposed method are reduced by about 33% compared with that of the two methods. In our work, the frame-to-frame displacements are further accumulated in time, to allow for the calculation of myocardial Lagrangian cardiac strains and point trajectories. Indeed, from the estimated trajectories in time on 11 in vivo data sets (9 patients and 2 healthy volunteers), the shape of myocardial point trajectories belonging to pathological regions are clearly reduced in magnitude compared with the ones from normal regions. Myocardial point trajectories, estimated from our phase-based analytic</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2853774','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2853774"><span>In Vitro <span class="hlt">Modeling</span> of Repetitive <span class="hlt">Motion</span> Injury and Myofascial Release</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Meltzer, Kate R.; Cao, Thanh V.; Schad, Joseph F.; King, Hollis; Stoll, Scott T.; Standley, Paul R.</p> <p>2010-01-01</p> <p>Objective In this study we <span class="hlt">modeled</span> repetitive <span class="hlt">motion</span> strain (RMS) and myofascial release (MFR) in vitro to investigate possible cellular and molecular mechanisms to potentially explain the immediate clinical outcomes associated with RMS and MFR. Method Cultured human fibroblasts were strained with 8 hours RMS, 60 seconds MFR and combined treatment; RMS+MFR. Fibroblasts were immediately sampled upon cessation of strain and evaluated for cell morphology, cytokine secretions, proliferation, apoptosis, and potential changes to intracellular signaling molecules. Results RMS induced fibroblast elongation of lameopodia, cellular decentralization, reduction of cell to cell contact and significant decreases in cell area to perimeter ratios compared to all other experimental groups (p<0.0001). Cellular proliferation indicated no change among any treatment group; however RMS resulted in a significant increase in apoptosis rate (p<0.05) along with increases in death-associated protein kinase (DAPK) and focal adhesion kinase (FAK) phosphorylation by 74% and 58% respectively, when compared to control. These responses were not observed in the MFR and RMS+MFR group. Of the twenty cytokines measured there was a significant increase in GRO secretion in the RMS+MFR group when compared to control and MFR alone. Conclusion Our <span class="hlt">modeled</span> injury (RMS) appropriately displayed enhanced apoptosis activity and loss of intercellular integrity that is consistent with pro-apoptotic DAPK2 and FAK signaling. Treatment with MFR following RMS resulted in normalization in apoptotic rate and cell morphology both consistent with changes observed in DAPK2. These in vitro studies build upon the cellular evidence base needed to fully explain clinical efficacy of manual manipulative therapies. PMID:20226363</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016PhLA..380.2809S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016PhLA..380.2809S"><span>A generalized Brownian <span class="hlt">motion</span> <span class="hlt">model</span> for turbulent relative particle dispersion</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Shivamoggi, B. K.</p> <p>2016-08-01</p> <p>There is speculation that the difficulty in obtaining an extended range with Richardson-Obukhov scaling in both laboratory experiments and numerical simulations is due to the finiteness of the flow Reynolds number Re in these situations. In this paper, a generalized Brownian <span class="hlt">motion</span> <span class="hlt">model</span> has been applied to describe the relative particle dispersion problem in more realistic turbulent flows and to shed some light on this issue. The fluctuating pressure forces acting on a fluid particle are taken to be a colored noise and follow a stationary process and are described by the Uhlenbeck-Ornstein <span class="hlt">model</span> while it appears plausible to take their correlation time to have a power-law dependence on Re, thus introducing a bridge between the Lagrangian quantities and the Eulerian parameters for this problem. This ansatz is in qualitative agreement with the possibility of a connection speculated earlier by Corrsin [26] between the white-noise representation for the fluctuating pressure forces and the large-Re assumption in the Kolmogorov [4] theory for the 3D fully developed turbulence (FDT) as well as a similar argument of Monin and Yaglom [23] and a similar result of Sawford [13] and Borgas and Sawford [24]. It also provides an insight into the result that the Richardson-Obukhov scaling holds only in the infinite-Re limit and disappears otherwise. This ansatz further provides a determination of the Richardson-Obukhov constant g as a function of Re, with an asymptotic constant value in the infinite-Re limit. It is shown to lead to full agreement, in the small-Re limit as well, with the Batchelor-Townsend [27] scaling for the rate of change of the mean square interparticle separation in 3D FDT, hence validating its soundness further.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19740025663','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19740025663"><span>Mathematical <span class="hlt">model</span> for the simulation of Dynamic Docking Test System (DDST) active table <span class="hlt">motion</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Gates, R. M.; Graves, D. L.</p> <p>1974-01-01</p> <p>The mathematical <span class="hlt">model</span> developed to describe the three-dimensional <span class="hlt">motion</span> of the dynamic docking test system active table is described. The active table is <span class="hlt">modeled</span> as a rigid body supported by six flexible hydraulic actuators which produce the commanded table <span class="hlt">motions</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2003EAEJA.....8130S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2003EAEJA.....8130S"><span>Hotspot <span class="hlt">motion</span> inferred from mantle flow <span class="hlt">models</span>: implications on global plate reconstructions</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Steinberger, B.; O'Connell, R. J.</p> <p>2003-04-01</p> <p>The Hawaiian hotspot track predicted from a plate circuit, assuming that the Hawaiian hotspot is fixed relative to African hotspots, does not fit the observed track: The divergence is steadily increasing back to 43 Ma, and the predicted track does not show a bend. Here we use a <span class="hlt">model</span> of plumes distorted by global mantle flow to compute hotspot <span class="hlt">motion</span>, and test whether this <span class="hlt">motion</span> can explain the misfit. Computations consistently predict a south- to southeastward <span class="hlt">motion</span> of the Hawaiian hotspot, and a <span class="hlt">motion</span> of about 1000 km southward during the past 80 Ma is within the range of <span class="hlt">model</span> results. Thus, we find that our <span class="hlt">model</span> of hotspot <span class="hlt">motion</span> can account for the divergence from 0 to 43 Ma, but can not account for the bend and the track prior to 43 Ma. For this, both a rather sharp change in hotspot <span class="hlt">motion</span> at 43 Ma, and a westward component of hotspot <span class="hlt">motion</span> prior to 43 Ma would be required, and neither is predicted in the <span class="hlt">model</span>. However, a combination of <span class="hlt">modelled</span> hotspot <span class="hlt">motion</span> and a relatively modest <span class="hlt">motion</span> between W and E Antarctica - about 15 degrees clockwise rotation of W vs. E Antarctica - would permit a fit to the Hawaiian track from 80 to 43 My. The required deformation could have been accomplished entirely within continental crust, with rates similar to e.g. present extension in the western U.S., and we will argue that it is not in conflict with, but actually supported by geologic evidence.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19870013324','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19870013324"><span>Numerical <span class="hlt">modeling</span> of on-orbit propellant <span class="hlt">motion</span> resulting from an impulsive acceleration</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Aydelott, John C.; Mjolsness, Raymond C.; Torrey, Martin D.; Hochstein, John I.</p> <p>1987-01-01</p> <p>In-space docking and separation maneuvers of spacecraft that have large fluid mass fractions may cause undesirable spacecraft <span class="hlt">motion</span> in response to the impulsive-acceleration-induced fluid <span class="hlt">motion</span>. An example of this potential low gravity fluid management problem arose during the development of the shuttle/Centaur vehicle. Experimentally verified numerical <span class="hlt">modeling</span> techniques were developed to establish the propellant dynamics, and subsequent vehicle <span class="hlt">motion</span>, associated with the separation of the Centaur vehicle from the shuttle orbiter cargo bay. Although the shuttle/Centaur development activity was suspended, the numerical <span class="hlt">modeling</span> techniques are available to predict on-orbit liquid <span class="hlt">motion</span> resulting from impulsive accelerations for other missions and spacecraft.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19870061299&hterms=Torrey+John&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3DTorrey%252C%2BJohn','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19870061299&hterms=Torrey+John&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3DTorrey%252C%2BJohn"><span>Numerical <span class="hlt">modeling</span> of on-orbit propellant <span class="hlt">motion</span> resulting from an impulsive acceleration</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Aydelott, John C.; Mjolsness, Raymond C.; Torrey, Martin D.; Hochstein, John I.</p> <p>1986-01-01</p> <p>In-space docking and separation maneuvers of spacecraft that have large fluid mass fractions may cause undersirable spacecraft <span class="hlt">motion</span> in response to the impulsive-acceleration-induced fluid <span class="hlt">motion</span>. An example of this potential low gravity fluid management problem arose during the development of the shuttle/Centaur vehicle. Experimentally verified numerical <span class="hlt">modeling</span> techniques were developed to establish the propellant dynamics, and subsequent vehicle <span class="hlt">motion</span>, associated with the separation of the Centaur vehicle from the shuttle orbiter cargo bay. Although the shuttle/Centaur development activity was suspended, the numerical <span class="hlt">modeling</span> techniques are available to predict on-orbit liquid <span class="hlt">motion</span> resulting from impulsive accelerations for other missions and spacecraft.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/19097093','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/19097093"><span>3D coronary <span class="hlt">motion</span> tracking in swine <span class="hlt">models</span> with MR tracking catheters.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Schmidt, Ehud J; Yoneyama, Ryuichi; Dumoulin, Charles L; Darrow, Robert D; Klein, Eric; Kiruluta, Andrew J M; Hayase, Motoya</p> <p>2009-01-01</p> <p>To develop MR-tracked catheters to delineate the three-dimensional <span class="hlt">motion</span> of coronary arteries at high spatial and temporal resolution. Catheters with three tracking microcoils were placed into nine swine. During breath-holds, electrocardiographic (ECG)-synchronized 3D <span class="hlt">motion</span> was measured at varying vessel depths. 3D <span class="hlt">motion</span> was measured in American Heart Association left anterior descending (LAD) segments 6-7, left circumflex (LCX) segments 11-15, and right coronary artery (RCA) segments 2-3, at 60-115 beats/min heart rates. Similar-length cardiac cycles were averaged. Intercoil cross-correlation identified early systolic phase (ES) and determined segment <span class="hlt">motion</span> delay. Translational and rotational <span class="hlt">motion</span>, as a function of cardiac phase, is shown, with directionality and amplitude varying along the vessel length. Rotation (peak-to-peak solid-angle RCA approximately 0.10, LAD approximately 0.06, LCX approximately 0.18 radian) occurs primarily during fast translational <span class="hlt">motion</span> and increases distally. LCX displacement increases with heart rate by 18%. Phantom simulations of <span class="hlt">motion</span> effects on high-resolution images, using RCA results, show artifacts due to translation and rotation. Magnetic resonance imaging (MRI) tracking catheters quantify <span class="hlt">motion</span> at 20 fps and 1 mm(3) resolution at <span class="hlt">multiple</span> vessel depths, exceeding that available with other techniques. Imaging artifacts due to rotation are demonstrated. <span class="hlt">Motion</span>-tracking catheters may provide physiological information during interventions and improve imaging spatial resolution.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20090029958','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20090029958"><span>Evaluating Effectiveness of <span class="hlt">Modeling</span> <span class="hlt">Motion</span> System Feedback in the Enhanced Hess Structural <span class="hlt">Model</span> of the Human Operator</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Zaychik, Kirill; Cardullo, Frank; George, Gary; Kelly, Lon C.</p> <p>2009-01-01</p> <p>In order to use the Hess Structural <span class="hlt">Model</span> to predict the need for certain cueing systems, George and Cardullo significantly expanded it by adding <span class="hlt">motion</span> feedback to the <span class="hlt">model</span> and incorporating <span class="hlt">models</span> of the <span class="hlt">motion</span> system dynamics, <span class="hlt">motion</span> cueing algorithm and a vestibular system. This paper proposes a methodology to evaluate effectiveness of these innovations by performing a comparison analysis of the <span class="hlt">model</span> performance with and without the expanded <span class="hlt">motion</span> feedback. The proposed methodology is composed of two stages. The first stage involves fine-tuning parameters of the original Hess structural <span class="hlt">model</span> in order to match the actual control behavior recorded during the experiments at NASA Visual <span class="hlt">Motion</span> Simulator (VMS) facility. The parameter tuning procedure utilizes a new automated parameter identification technique, which was developed at the Man-Machine Systems Lab at SUNY Binghamton. In the second stage of the proposed methodology, an expanded <span class="hlt">motion</span> feedback is added to the structural <span class="hlt">model</span>. The resulting performance of the <span class="hlt">model</span> is then compared to that of the original one. As proposed by Hess, metrics to evaluate the performance of the <span class="hlt">models</span> include comparison against the crossover <span class="hlt">models</span> standards imposed on the crossover frequency and phase margin of the overall man-machine system. Preliminary results indicate the advantage of having the <span class="hlt">model</span> of the <span class="hlt">motion</span> system and <span class="hlt">motion</span> cueing incorporated into the <span class="hlt">model</span> of the human operator. It is also demonstrated that the crossover frequency and the phase margin of the expanded <span class="hlt">model</span> are well within the limits imposed by the crossover <span class="hlt">model</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014cosp...40E3641W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014cosp...40E3641W"><span>Hydrological excitation of polar <span class="hlt">motion</span> by different variables of the GLDAS <span class="hlt">models</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wińska, Małgorzata; Nastula, Jolanta</p> <p></p> <p>Continental hydrological loading, by land water, snow, and ice, is an element that is strongly needed for a full understanding of the excitation of polar <span class="hlt">motion</span>. In this study we compute different estimations of hydrological excitation functions of polar <span class="hlt">motion</span> (Hydrological Angular Momentum - HAM) using various variables from the Global Land Data Assimilation System (GLDAS) <span class="hlt">models</span> of land hydrosphere. The main aim of this study is to show the influence of different variables for example: total evapotranspiration, runoff, snowmelt, soil moisture to polar <span class="hlt">motion</span> excitations in annual and short term scale. In our consideration we employ several realizations of the GLDAS <span class="hlt">model</span> as: GLDAS Common Land <span class="hlt">Model</span> (CLM), GLDAS Mosaic <span class="hlt">Model</span>, GLDAS National Centers for Environmental Prediction/Oregon State University/Air Force/Hydrologic Research Lab <span class="hlt">Model</span> (Noah), GLDAS Variable Infiltration Capacity (VIC) <span class="hlt">Model</span>. Hydrological excitation functions of polar <span class="hlt">motion</span>, both global and regional, are determined by using selected variables of these GLDAS realizations. First we compare a timing, spectra and phase diagrams of different regional and global HAMs with each other. Next, we estimate, the hydrological signal in geodetically observed polar <span class="hlt">motion</span> excitation by subtracting the atmospheric -- AAM (pressure + wind) and oceanic -- OAM (bottom pressure + currents) contributions. Finally, the hydrological excitations are compared to these hydrological signal in observed polar <span class="hlt">motion</span> excitation series. The results help us understand which variables of considered hydrological <span class="hlt">models</span> are the most important for the polar <span class="hlt">motion</span> excitation and how well we can close polar <span class="hlt">motion</span> excitation budget in the seasonal and inter-annual spectral ranges.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5341056','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5341056"><span>EEG frequency tagging dissociates between neural processing of <span class="hlt">motion</span> synchrony and human quality of <span class="hlt">multiple</span> point-light dancers</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Alp, Nihan; Nikolaev, Andrey R.; Wagemans, Johan; Kogo, Naoki</p> <p>2017-01-01</p> <p>Do we perceive a group of dancers moving in synchrony differently from a group of drones flying in-sync? The brain has dedicated networks for perception of coherent <span class="hlt">motion</span> and interacting human bodies. However, it is unclear to what extent the underlying neural mechanisms overlap. Here we delineate these mechanisms by independently manipulating the degree of <span class="hlt">motion</span> synchrony and the humanoid quality of <span class="hlt">multiple</span> point-light displays (PLDs). Four PLDs moving within a group were changing contrast in cycles of fixed frequencies, which permits the identification of the neural processes that are tagged by these frequencies. In the frequency spectrum of the steady-state EEG we found two emergent frequency components, which signified distinct levels of interactions between PLDs. The first component was associated with <span class="hlt">motion</span> synchrony, the second with the human quality of the moving items. These findings indicate that visual processing of synchronously moving dancers involves two distinct neural mechanisms: one for the perception of a group of items moving in synchrony and one for the perception of a group of moving items with human quality. We propose that these mechanisms underlie high-level perception of social interactions. PMID:28272421</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/20876013','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/20876013"><span>Statistical <span class="hlt">modeling</span> of 4D respiratory lung <span class="hlt">motion</span> using diffeomorphic image registration.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Ehrhardt, Jan; Werner, René; Schmidt-Richberg, Alexander; Handels, Heinz</p> <p>2011-02-01</p> <p><span class="hlt">Modeling</span> of respiratory <span class="hlt">motion</span> has become increasingly important in various applications of medical imaging (e.g., radiation therapy of lung cancer). Current <span class="hlt">modeling</span> approaches are usually confined to intra-patient registration of 3D image data representing the individual patient's anatomy at different breathing phases. We propose an approach to generate a mean <span class="hlt">motion</span> <span class="hlt">model</span> of the lung based on thoracic 4D computed tomography (CT) data of different patients to extend the <span class="hlt">motion</span> <span class="hlt">modeling</span> capabilities. Our <span class="hlt">modeling</span> process consists of three steps: an intra-subject registration to generate subject-specific <span class="hlt">motion</span> <span class="hlt">models</span>, the generation of an average shape and intensity atlas of the lung as anatomical reference frame, and the registration of the subject-specific <span class="hlt">motion</span> <span class="hlt">models</span> to the atlas in order to build a statistical 4D mean <span class="hlt">motion</span> <span class="hlt">model</span> (4D-MMM). Furthermore, we present methods to adapt the 4D mean <span class="hlt">motion</span> <span class="hlt">model</span> to a patient-specific lung geometry. In all steps, a symmetric diffeomorphic nonlinear intensity-based registration method was employed. The Log-Euclidean framework was used to compute statistics on the diffeomorphic transformations. The presented methods are then used to build a mean <span class="hlt">motion</span> <span class="hlt">model</span> of respiratory lung <span class="hlt">motion</span> using thoracic 4D CT data sets of 17 patients. We evaluate the <span class="hlt">model</span> by applying it for estimating respiratory <span class="hlt">motion</span> of ten lung cancer patients. The prediction is evaluated with respect to landmark and tumor <span class="hlt">motion</span>, and the quantitative analysis results in a mean target registration error (TRE) of 3.3 ±1.6 mm if lung dynamics are not impaired by large lung tumors or other lung disorders (e.g., emphysema). With regard to lung tumor <span class="hlt">motion</span>, we show that prediction accuracy is independent of tumor size and tumor <span class="hlt">motion</span> amplitude in the considered data set. However, tumors adhering to non-lung structures degrade local lung dynamics significantly and the <span class="hlt">model</span>-based prediction accuracy is lower in these cases. The statistical respiratory</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25939490','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25939490"><span>Posterior predictive checking of <span class="hlt">multiple</span> imputation <span class="hlt">models</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Nguyen, Cattram D; Lee, Katherine J; Carlin, John B</p> <p>2015-07-01</p> <p><span class="hlt">Multiple</span> imputation is gaining popularity as a strategy for handling missing data, but there is a scarcity of tools for checking imputation <span class="hlt">models</span>, a critical step in <span class="hlt">model</span> fitting. Posterior predictive checking (PPC) has been recommended as an imputation diagnostic. PPC involves simulating "replicated" data from the posterior predictive distribution of the <span class="hlt">model</span> under scrutiny. <span class="hlt">Model</span> fit is assessed by examining whether the analysis from the observed data appears typical of results obtained from the replicates produced by the <span class="hlt">model</span>. A proposed diagnostic measure is the posterior predictive "p-value", an extreme value of which (i.e., a value close to 0 or 1) suggests a misfit between the <span class="hlt">model</span> and the data. The aim of this study was to evaluate the performance of the posterior predictive p-value as an imputation diagnostic. Using simulation methods, we deliberately misspecified imputation <span class="hlt">models</span> to determine whether posterior predictive p-values were effective in identifying these problems. When estimating the regression parameter of interest, we found that more extreme p-values were associated with poorer imputation <span class="hlt">model</span> performance, although the results highlighted that traditional thresholds for classical p-values do not apply in this context. A shortcoming of the PPC method was its reduced ability to detect misspecified <span class="hlt">models</span> with increasing amounts of missing data. Despite the limitations of posterior predictive p-values, they appear to have a valuable place in the imputer's toolkit. In addition to automated checking using p-values, we recommend imputers perform graphical checks and examine other summaries of the test quantity distribution. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/16835641','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/16835641"><span>Angular <span class="hlt">motion</span> point spread function <span class="hlt">model</span> considering aberrations and defocus effects.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Klapp, Iftach; Yitzhaky, Yitzhak</p> <p>2006-08-01</p> <p>When <span class="hlt">motion</span> blur is considered, the optics point spread function (PSF) is conventionally assumed to be fixed, and therefore cascading of the <span class="hlt">motion</span> optical transfer function (OTF) with the optics OTF is allowed. However, in angular <span class="hlt">motion</span> conditions, the image is distorted by space-variant effects of wavefront aberrations, defocus, and <span class="hlt">motion</span> blur. The proposed <span class="hlt">model</span> considers these effects and formulates a combined space-variant PSF obtained from the angle-dependent optics PSF and the <span class="hlt">motion</span> PSF that acts as a weighting function. Results of comparison of the new angular-<span class="hlt">motion</span>-dependent PSF and the traditional PSF show significant differences. To simplify the proposed <span class="hlt">model</span>, an efficient approximation is suggested and evaluated.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.dtic.mil/docs/citations/ADA129565','DTIC-ST'); return false;" href="http://www.dtic.mil/docs/citations/ADA129565"><span>Recovering 2-D <span class="hlt">Motion</span> Parameters in Scenes Containing <span class="hlt">Multiple</span> Moving Objects.</span></a></p> <p><a target="_blank" href="http://www.dtic.mil/">DTIC Science & Technology</a></p> <p></p> <p>1983-05-01</p> <p>resolution scheme in both the image plane and the parameter space and thus redue, the computationa cost of the technique. The method is demonstrated...by experiments " on artificial imags with four parameters of 2-1) <span class="hlt">motion</span>: rotation, expansion and translation in both axes. This paper will appear in...the proceedings of the DARPA Image Ud Workshop, to be held in Arlington VA, June 193. (T IC ____ ____LEC TErf ’ r~i dcmnth3beenarod AW T,,i2 1101 I.. I</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/946928','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/946928"><span>Ground <span class="hlt">motion</span> <span class="hlt">modeling</span> of the 1906 San Francisco earthquake II: Ground <span class="hlt">motion</span> estimates for the 1906 earthquake and scenario events</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Aagaard, B; Brocher, T; Dreger, D; Frankel, A; Graves, R; Harmsen, S; Hartzell, S; Larsen, S; McCandless, K; Nilsson, S; Petersson, N A; Rodgers, A; Sjogreen, B; Tkalcic, H; Zoback, M L</p> <p>2007-02-09</p> <p>We estimate the ground <span class="hlt">motions</span> produced by the 1906 San Francisco earthquake making use of the recently developed Song et al. (2008) source <span class="hlt">model</span> that combines the available geodetic and seismic observations and recently constructed 3D geologic and seismic velocity <span class="hlt">models</span>. Our estimates of the ground <span class="hlt">motions</span> for the 1906 earthquake are consistent across five ground-<span class="hlt">motion</span> <span class="hlt">modeling</span> groups employing different wave propagation codes and simulation domains. The simulations successfully reproduce the main features of the Boatwright and Bundock (2005) ShakeMap, but tend to over predict the intensity of shaking by 0.1-0.5 modified Mercalli intensity (MMI) units. Velocity waveforms at sites throughout the San Francisco Bay Area exhibit characteristics consistent with rupture directivity, local geologic conditions (e.g., sedimentary basins), and the large size of the event (e.g., durations of strong shaking lasting tens of seconds). We also compute ground <span class="hlt">motions</span> for seven hypothetical scenarios rupturing the same extent of the northern San Andreas fault, considering three additional hypocenters and an additional, random distribution of slip. Rupture directivity exerts the strongest influence on the variations in shaking, although sedimentary basins do consistently contribute to the response in some locations, such as Santa Rosa, Livermore, and San Jose. These scenarios suggest that future large earthquakes on the northern San Andreas fault may subject the current San Francisco Bay urban area to stronger shaking than a repeat of the 1906 earthquake. Ruptures propagating southward towards San Francisco appear to expose more of the urban area to a given intensity level than do ruptures propagating northward.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li class="active"><span>16</span></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_16 --> <div id="page_17" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li class="active"><span>17</span></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="321"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015aste.book..183D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015aste.book..183D"><span>Asteroid <span class="hlt">Models</span> from <span class="hlt">Multiple</span> Data Sources</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Durech, J.; Carry, B.; Delbo, M.; Kaasalainen, M.; Viikinkoski, M.</p> <p></p> <p>In the past decade, hundreds of asteroid shape <span class="hlt">models</span> have been derived using the lightcurve inversion method. At the same time, a new framework of three-dimensional shape <span class="hlt">modeling</span> based on the combined analysis of widely different data sources -- such as optical lightcurves, disk-resolved images, stellar occultation timings, mid-infrared thermal radiometry, optical interferometry, and radar delay-Doppler data -- has been developed. This multi-data approach allows the determination of most of the physical and surface properties of asteroids in a single, coherent inversion, with spectacular results. We review the main results of asteroid lightcurve inversion and also recent advances in multi-data <span class="hlt">modeling</span>. We show that <span class="hlt">models</span> based on remote sensing data were confirmed by spacecraft encounters with asteroids, and we discuss how the <span class="hlt">multiplication</span> of highly detailed three-dimensional <span class="hlt">models</span> will help to refine our general knowledge of the asteroid population. The physical and surface properties of asteroids, i.e., their spin, three-dimensional shape, density, thermal inertia, and surface roughness, are among the least known of all asteroid properties. Apart from the albedo and diameter, we have access to the whole picture for only a few hundreds of asteroids. These quantities are nevertheless very important to understand, as they affect the nongravitational Yarkovsky effect responsible for meteorite delivery to Earth, as well as the bulk composition and internal structure of asteroids.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5015541','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5015541"><span>The topographical <span class="hlt">model</span> of <span class="hlt">multiple</span> sclerosis</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Cook, Karin; De Nino, Scott; Fletcher, Madhuri</p> <p>2016-01-01</p> <p>Relapses and progression contribute to <span class="hlt">multiple</span> sclerosis (MS) disease course, but neither the relationship between them nor the spectrum of clinical heterogeneity has been fully characterized. A hypothesis-driven, biologically informed <span class="hlt">model</span> could build on the clinical phenotypes to encompass the dynamic admixture of factors underlying MS disease course. In this medical hypothesis, we put forth a dynamic <span class="hlt">model</span> of MS disease course that incorporates localization and other drivers of disability to propose a clinical manifestation framework that visualizes MS in a clinically individualized way. The topographical <span class="hlt">model</span> encapsulates 5 factors (localization of relapses and causative lesions; relapse frequency, severity, and recovery; and progression rate), visualized utilizing dynamic 3-dimensional renderings. The central hypothesis is that, like symptom recrudescence in Uhthoff phenomenon and pseudoexacerbations, progression clinically recapitulates prior relapse symptoms and unmasks previously silent lesions, incrementally revealing underlying lesion topography. The <span class="hlt">model</span> uses real-time simulation software to depict disease course archetypes and illuminate several well-described but poorly reconciled phenomena including the clinical/MRI paradox and prognostic significance of lesion location and burden on disease outcomes. Utilization of this <span class="hlt">model</span> could allow for earlier and more clinically precise identification of progressive MS and predictive implications can be empirically tested. PMID:27648465</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2775489','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2775489"><span>Whole-<span class="hlt">Motion</span> <span class="hlt">Model</span> of Perception during Forward- and Backward-Facing Centrifuge Runs</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Holly, Jan E.; Vrublevskis, Arturs; Carlson, Lindsay E.</p> <p>2009-01-01</p> <p>Illusory perceptions of <span class="hlt">motion</span> and orientation arise during human centrifuge runs without vision. Asymmetries have been found between acceleration and deceleration, and between forward-facing and backward-facing runs. Perceived roll tilt has been studied extensively during upright fixed-carriage centrifuge runs, and other components have been studied to a lesser extent. Certain, but not all, perceptual asymmetries in acceleration-vs-deceleration and forward-vs-backward <span class="hlt">motion</span> can be explained by existing analyses. The immediate acceleration-deceleration roll-tilt asymmetry can be explained by the three-dimensional physics of the external stimulus; in addition, longer-term data has been <span class="hlt">modeled</span> in a standard way using physiological time constants. However, the standard <span class="hlt">modeling</span> approach is shown in the present research to predict forward-vs-backward-facing symmetry in perceived roll tilt, contradicting experimental data, and to predict perceived sideways <span class="hlt">motion</span>, rather than forward or backward <span class="hlt">motion</span>, around a curve. The present work develops a different whole-<span class="hlt">motion</span>-based <span class="hlt">model</span> taking into account the three-dimensional form of perceived <span class="hlt">motion</span> and orientation. This <span class="hlt">model</span> predicts perceived forward or backward <span class="hlt">motion</span> around a curve, and predicts additional asymmetries such as the forward-backward difference in roll tilt. This <span class="hlt">model</span> is based upon many of the same principles as the standard <span class="hlt">model</span>, but includes an additional concept of familiarity of <span class="hlt">motions</span> as a whole. PMID:19208962</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2003APS..MAR.P9004G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2003APS..MAR.P9004G"><span>Minimal Assumptions Comprehensive Electrostatic <span class="hlt">Model</span> for Mitotic <span class="hlt">Motions</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gagliardi, L. John</p> <p>2003-03-01</p> <p>Primitive biological cells had to divide using very few biological mechanisms. This work proposes physicochemical mechanisms based on nanoscale electrostatics which explain and unify the basic <span class="hlt">motions</span> during mitosis: (1) assembly of the asters, (2) <span class="hlt">motion</span> of asters to poles, (3) chromosome attachment, (4) separation of sister chromatids, (5) prometaphase monovalent attachment <span class="hlt">motions</span>, (6) chromosome congression to the cell equator, (7) metaphase oscillations, and (8) anaphase A poleward chromosome <span class="hlt">motion</span>. In the cytosol of cells, electrostatic fields are subject to strong attenuation by ionic screening. However, the presence of microtubules within cells changes the situation completely. Microtubule dimer subunits are electric dipolar structures, and can act as intermediaries which extend the reach of the electrostatic interaction over cellular distances. Experimental studies have shown that intracellular pH rises to a peak at mitosis, and decreases through cytokinesis. This result, in conjunction with the electric dipole nature of microtubule subunits is sufficient to explain the dynamics of the above events and <span class="hlt">motions</span>, including their timing and sequencing. The physicochemical methods utilized by primitive eukaryotic cells could provide important clues regarding our understanding of cell division in modern eukaryotic cells.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1997JMagR.127..147G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1997JMagR.127..147G"><span>REDOR Dephasing by <span class="hlt">Multiple</span> Spins in the Presence of Molecular <span class="hlt">Motion</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Goetz, Jon M.; Schaefer, Jacob</p> <p>1997-08-01</p> <p>Closed-form, numerical algorithms are presented for calculating REDOR dephasing for three general cases: (i) collections of isolatedI-Sspin pairs; (ii) manySspins coupled to anIspin; and (iii) anI-Sspin pair in relative <span class="hlt">motion</span>. For the case when more than oneSspin is dipolar coupled to anIspin, the calculation assumes that theS-Shomonuclear interaction does not affect REDOR dephasing. Full numerical simulations show that this assumption is true if theS-spin lineshapes are inhomogeneously broadened, theS-spin chemical shifts are far from rotational resonance, and a version of REDOR is used which minimizes the number ofS-spin π pulses. For the rapidly rotating -CF3group of poly(trifluoroethyl methacrylate), the formalisms of (ii) and (iii) are combined to calculate the dephasing. The experimentally measured dephasing matches theory when the wiggling <span class="hlt">motion</span> of the -OCH2CF3moiety of the polymer is taken into account.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27139880','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27139880"><span>Pentagraph image fusion scheme for <span class="hlt">motion</span> blur prevention using <span class="hlt">multiple</span> monochromatic images.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Volfman, Alon A; Mendlovic, David; Raz, Ariel</p> <p>2016-04-10</p> <p>This paper introduces the pentagraph image fusion (PIF) scheme for <span class="hlt">motion</span>-related blur prevention in images. The PIF algorithm processes five monochromatic images into a single, low-noise, no-blur color image. The images are acquired using a new photography scheme, sequential filter photography (SFP), where instead of using a stationary Bayer pattern color filter array in front of the image sensor, a tunable color filter array is used. Using this approach, several monochromatic images are captured one by one and later fused into one color image. The SFP introduces various advantages such as higher resolution, better SNR, and the ability to control both exposure time and color filter separately for each image. The PIF algorithm harnesses all the advantages of SFP for the first time, to the best of our knowledge, in the field of blur-free image acquisition. Five images are taken with controllable exposure time and color filter, three images for the color bands, and two high-signal panchromatic images. These images are fused together to be a single, low-noise, no-blur color image. The algorithm presents a generic approach of dealing with both local and global <span class="hlt">motion</span> blur and does not require any user intervention.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015PhTea..53...17C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015PhTea..53...17C"><span>Using "Flatland 2: Sphereland" to Help Teach <span class="hlt">Motion</span> and <span class="hlt">Multiple</span> Dimensions</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Caplan, Seth; Johnson, Dano; Vondracek, Mark</p> <p>2015-01-01</p> <p>The 1884 book Flatland: A Romance of Many Dimensions,1 written by Edwin Abbott, has captured the interest of numerous generations, and has also been used in schools to help students learn and think about the concept of dimension in a creative, fun way. In 2007, a film was released called "Flatland: The Movie,"2 and over one million students have watched it worldwide, primarily in mathematics classes. Since then, a sequel to the "Flatland" movie was released in 2012, entitled "Flatland 2: Sphereland."3 A primary goal of this sequel is to expand the use of the movie beyond mathematics classes and into physics classes because a central premise to "Sphereland" is the notion of warped space. This latest movie provides an engaging and interesting visual way for students to think about both dimension and <span class="hlt">motion</span> through warped space. In addition, basic <span class="hlt">motion</span> concepts such as speed and acceleration can be studied by students in introductory physics classes, for instance, by using frame-by-frame analysis of various scenes in the movie.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27107032','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27107032"><span><span class="hlt">Motion</span> analysis study on sensitivity of finite element <span class="hlt">model</span> of the cervical spine to geometry.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Zafarparandeh, Iman; Erbulut, Deniz U; Ozer, Ali F</p> <p>2016-07-01</p> <p>Numerous finite element <span class="hlt">models</span> of the cervical spine have been proposed, with exact geometry or with symmetric approximation in the geometry. However, few researches have investigated the sensitivity of predicted <span class="hlt">motion</span> responses to the geometry of the cervical spine. The goal of this study was to evaluate the effect of symmetric assumption on the predicted <span class="hlt">motion</span> by finite element <span class="hlt">model</span> of the cervical spine. We developed two finite element <span class="hlt">models</span> of the cervical spine C2-C7. One <span class="hlt">model</span> was based on the exact geometry of the cervical spine (asymmetric <span class="hlt">model</span>), whereas the other was symmetric (symmetric <span class="hlt">model</span>) about the mid-sagittal plane. The predicted range of <span class="hlt">motion</span> of both <span class="hlt">models</span>-main and coupled <span class="hlt">motions</span>-was compared with published experimental data for all <span class="hlt">motion</span> planes under a full range of loads. The maximum differences between the asymmetric <span class="hlt">model</span> and symmetric <span class="hlt">model</span> predictions for the principal <span class="hlt">motion</span> were 31%, 78%, and 126% for flexion-extension, right-left lateral bending, and right-left axial rotation, respectively. For flexion-extension and lateral bending, the minimum difference was 0%, whereas it was 2% for axial rotation. The maximum coupled <span class="hlt">motions</span> predicted by the symmetric <span class="hlt">model</span> were 1.5° axial rotation and 3.6° lateral bending, under applied lateral bending and axial rotation, respectively. Those coupled <span class="hlt">motions</span> predicted by the asymmetric <span class="hlt">model</span> were 1.6° axial rotation and 4° lateral bending, under applied lateral bending and axial rotation, respectively. In general, the predicted <span class="hlt">motion</span> response of the cervical spine by the symmetric <span class="hlt">model</span> was in the acceptable range and nonlinearity of the moment-rotation curve for the cervical spine was properly predicted.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19950021351','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19950021351"><span>Attitude determination using an adaptive <span class="hlt">multiple</span> <span class="hlt">model</span> filtering Scheme</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Lam, Quang; Ray, Surendra N.</p> <p>1995-01-01</p> <p>Attitude determination has been considered as a permanent topic of active research and perhaps remaining as a forever-lasting interest for spacecraft system designers. Its role is to provide a reference for controls such as pointing the directional antennas or solar panels, stabilizing the spacecraft or maneuvering the spacecraft to a new orbit. Least Square Estimation (LSE) technique was utilized to provide attitude determination for the Nimbus 6 and G. Despite its poor performance (estimation accuracy consideration), LSE was considered as an effective and practical approach to meet the urgent need and requirement back in the 70's. One reason for this poor performance associated with the LSE scheme is the lack of dynamic filtering or 'compensation'. In other words, the scheme is based totally on the measurements and no attempts were made to <span class="hlt">model</span> the dynamic equations of <span class="hlt">motion</span> of the spacecraft. We propose an adaptive filtering approach which employs a bank of Kalman filters to perform robust attitude estimation. The proposed approach, whose architecture is depicted, is essentially based on the latest proof on the interactive <span class="hlt">multiple</span> <span class="hlt">model</span> design framework to handle the unknown of the system noise characteristics or statistics. The concept fundamentally employs a bank of Kalman filter or submodel, instead of using fixed values for the system noise statistics for each submodel (per operating condition) as the traditional <span class="hlt">multiple</span> <span class="hlt">model</span> approach does, we use an on-line dynamic system noise identifier to 'identify' the system noise level (statistics) and update the filter noise statistics using 'live' information from the sensor <span class="hlt">model</span>. The advanced noise identifier, whose architecture is also shown, is implemented using an advanced system identifier. To insure the robust performance for the proposed advanced system identifier, it is also further reinforced by a learning system which is implemented (in the outer loop) using neural networks to identify other unknown</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27558715','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27558715"><span><span class="hlt">Modeling</span> Functional <span class="hlt">Motions</span> of Biological Systems by Customized Natural Moves.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Demharter, Samuel; Knapp, Bernhard; Deane, Charlotte M; Minary, Peter</p> <p>2016-08-23</p> <p>Simulating the functional <span class="hlt">motions</span> of biomolecular systems requires large computational resources. We introduce a computationally inexpensive protocol for the systematic testing of hypotheses regarding the dynamic behavior of proteins and nucleic acids. The protocol is based on natural move Monte Carlo, a highly efficient conformational sampling method with built-in customization capabilities that allows researchers to design and perform a large number of simulations to investigate functional <span class="hlt">motions</span> in biological systems. We demonstrate the use of this protocol on both a protein and a DNA case study. Firstly, we investigate the plasticity of a class II major histocompatibility complex in the absence of a bound peptide. Secondly, we study the effects of the epigenetic mark 5-hydroxymethyl on cytosine on the structure of the Dickerson-Drew dodecamer. We show how our customized natural moves protocol can be used to investigate causal relationships of functional <span class="hlt">motions</span> in biological systems.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1980JChPh..73.4688R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1980JChPh..73.4688R"><span>A simple <span class="hlt">model</span> for internal <span class="hlt">motion</span> of DNA based upon EPR studies in the slow <span class="hlt">motion</span> region</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Robinson, B. H.; Forgacs, G.; Dalton, L. R.; Frisch, H. L.</p> <p>1980-11-01</p> <p>We develop a simplified theory of the EPR response from a spin-labeled intercalator bound to DNA by solving the stochastic Liouvillle equation in which the internal <span class="hlt">motions</span> of the base pairs of the DNA are considered lattice variables. The dynamics are treated by a discrete version of the continuously elastic rod. The discrete <span class="hlt">model</span> consists of harmonically coupled base pairs or disks which undergo Brownian rotational <span class="hlt">motion</span> in solution. Correlation functions are obtained from the Langevin equation rather than from the Fokker-Planck equation. Apparent rotational times from the linear response theory results are compared with available experimental data. Reasonable agreement between the predictions of this simplified theory and experiment is obtained.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/11114233','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/11114233"><span>Center of gravity <span class="hlt">motions</span> and ankle joint stiffness control in upright undisturbed stance <span class="hlt">modeled</span> through a fractional Brownian <span class="hlt">motion</span> framework.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Rougier, P; Caron, O</p> <p>2000-12-01</p> <p>The authors <span class="hlt">modeled</span> the center of gravity vertical projection (CG(v)) and the difference, CP - CG(v), which, combined, constitute the center of pressure (CP) trajectory, as fractional Brownian <span class="hlt">motion</span> in order to investigate their relative contributions and their spatiotemporal articulation. The results demonstrated that CG(v) and CP - CG(v) <span class="hlt">motions</span> are both endowed in complementary fashion with strong stochastic and part-deterministic behaviors. In addition, if the temporal coordinates remain similar for all 3 trajectories by definition, the switch between the successive control mechanisms appears for shorter displacements for CP - CG(v) and CG(v) than for CP trajectories. Results deduced from both input (CG(v)) and muscular stiffness (CP - CG(v)) thus provide insight into the way the central nervous system regulates stance control and in particular how CG and CP - CG are controlled.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/22407823','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/22407823"><span>TU-F-17A-03: An Analytical Respiratory Perturbation <span class="hlt">Model</span> for Lung <span class="hlt">Motion</span> Prediction</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Li, G; Yuan, A; Wei, J</p> <p>2014-06-15</p> <p>Purpose: Breathing irregularity is common, causing unreliable prediction in tumor <span class="hlt">motion</span> for correlation-based surrogates. Both tidal volume (TV) and breathing pattern (BP=ΔVthorax/TV, where TV=ΔVthorax+ΔVabdomen) affect lung <span class="hlt">motion</span> in anterior-posterior and superior-inferior directions. We developed a novel respiratory <span class="hlt">motion</span> perturbation (RMP) <span class="hlt">model</span> in analytical form to account for changes in TV and BP in <span class="hlt">motion</span> prediction from simulation to treatment. Methods: The RMP <span class="hlt">model</span> is an analytical function of patient-specific anatomic and physiologic parameters. It contains a base-<span class="hlt">motion</span> trajectory d(x,y,z) derived from a 4-dimensional computed tomography (4DCT) at simulation and a perturbation term Δd(ΔTV,ΔBP) accounting for deviation at treatment from simulation. The perturbation is dependent on tumor-specific location and patient-specific anatomy. Eleven patients with simulation and treatment 4DCT images were used to assess the RMP method in <span class="hlt">motion</span> prediction from 4DCT1 to 4DCT2, and vice versa. For each patient, ten <span class="hlt">motion</span> trajectories of corresponding points in the lower lobes were measured in both 4DCTs: one served as the base-<span class="hlt">motion</span> trajectory and the other as the ground truth for comparison. In total, 220 <span class="hlt">motion</span> trajectory predictions were assessed. The <span class="hlt">motion</span> discrepancy between two 4DCTs for each patient served as a control. An established 5D <span class="hlt">motion</span> <span class="hlt">model</span> was used for comparison. Results: The average absolute error of RMP <span class="hlt">model</span> prediction in superior-inferior direction is 1.6±1.8 mm, similar to 1.7±1.6 mm from the 5D <span class="hlt">model</span> (p=0.98). Some uncertainty is associated with limited spatial resolution (2.5mm slice thickness) and temporal resolution (10-phases). Non-corrected <span class="hlt">motion</span> discrepancy between two 4DCTs is 2.6±2.7mm, with the maximum of ±20mm, and correction is necessary (p=0.01). Conclusion: The analytical <span class="hlt">motion</span> <span class="hlt">model</span> predicts lung <span class="hlt">motion</span> with accuracy similar to the 5D <span class="hlt">model</span>. The analytical <span class="hlt">model</span> is based on physical relationships, requires no</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017SoPh..292...58Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017SoPh..292...58Z"><span>Main Cause of the Poloidal Plasma <span class="hlt">Motion</span> Inside a Magnetic Cloud Inferred from <span class="hlt">Multiple</span>-Spacecraft Observations</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhao, Ake; Wang, Yuming; Chi, Yutian; Liu, Jiajia; Shen, Chenglong; Liu, Rui</p> <p>2017-04-01</p> <p>Although the dynamical evolution of magnetic clouds (MCs) has been one of the foci of interplanetary physics for decades, only few studies focus on the internal properties of large-scale MCs. Recent work by Wang et al. ( J. Geophys. Res. 120, 1543, 2015) suggested the existence of the poloidal plasma <span class="hlt">motion</span> in MCs. However, the main cause of this <span class="hlt">motion</span> is not clear. In order to find it, we identify and reconstruct the MC observed by the Solar Terrestrial Relations Observatory (STEREO)-A, Wind, and STEREO-B spacecraft during 19 - 20 November 2007 with the aid of the velocity-modified cylindrical force-free flux-rope <span class="hlt">model</span>. We analyze the plasma velocity in the plane perpendicular to the MC axis. It is found that there was evident poloidal <span class="hlt">motion</span> at Wind and STEREO-B, but this was not clear at STEREO-A, which suggests a local cause rather than a global cause for the poloidal plasma <span class="hlt">motion</span> inside the MC. The rotational directions of the solar wind and MC plasma at the two sides of the MC boundary are found to be consistent, and the values of the rotational speeds of the solar wind and MC plasma at the three spacecraft show a rough correlation. All of these results illustrate that the interaction with ambient solar wind through viscosity might be one of the local causes of the poloidal <span class="hlt">motion</span>. Additionally, we propose another possible local cause: the existence of a pressure gradient in the MC. The significant difference in the total pressure at the three spacecraft suggests that this speculation is perhaps correct.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19820002202','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19820002202"><span>A mathematical <span class="hlt">model</span> of LANDSAT-D attitude dynamics with internal <span class="hlt">motion</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Oh, S. D.; Abshire, G. W.; Buckley, J. M.</p> <p>1981-01-01</p> <p>An algorithm to <span class="hlt">model</span> the effects of internal <span class="hlt">motion</span> by the solar array and the high gain antenna on the attitude of the LANDSAT-D spacecraft is presented. The relative torque and angular momenta arising from the internal <span class="hlt">motions</span> are assumed to be attitude independent but are considered to be a source of attitude perturbations. The equation of <span class="hlt">motion</span> for the three body problem is derived and then compared with the one body case. The effect of the internal <span class="hlt">motion</span> on the control of the spacecraft is shown in a computer study of the problem.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/5725707','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/5725707"><span>Correlations in <span class="hlt">multiple</span> production in nuclei and the Glauber <span class="hlt">model</span> for <span class="hlt">multiple</span> scattering</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Zoller, V.R.; Nikolayev, N.N.</p> <p>1982-10-01</p> <p>The Capella-Krzywicki-Shabelskii extension of the Glauber <span class="hlt">multiple</span>-scattering <span class="hlt">model</span> to the <span class="hlt">multiple</span> production of particles in nuclei is applied to the description of correlation phenomena and analyzed critically.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1034790','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1034790"><span>Comparison of Nonlinear <span class="hlt">Model</span> Results Using Modified Recorded and Synthetic Ground <span class="hlt">Motions</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Robert E. Spears; J. Kevin Wilkins</p> <p>2011-11-01</p> <p>A study has been performed that compares results of nonlinear <span class="hlt">model</span> runs using two sets of earthquake ground <span class="hlt">motion</span> time histories that have been modified to fit the same design response spectra. The time histories include applicable modified recorded earthquake ground <span class="hlt">motion</span> time histories and synthetic ground <span class="hlt">motion</span> time histories. The modified recorded earthquake ground <span class="hlt">motion</span> time histories are modified from time history records that are selected based on consistent magnitude and distance. The synthetic ground <span class="hlt">motion</span> time histories are generated using appropriate Fourier amplitude spectrums, Arias intensity, and drift correction. All of the time history modification is performed using the same algorithm to fit the design response spectra. The study provides data to demonstrate that properly managed synthetic ground <span class="hlt">motion</span> time histories are reasonable for use in nonlinear seismic analysis.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006SPIE.6144..838L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006SPIE.6144..838L"><span><span class="hlt">Modeling</span> lung <span class="hlt">motion</span> using consistent image registration in four-dimensional computed tomography for radiation therapy</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lu, Wei; Song, Joo Hyun; Christensen, Gary E.; Parikh, Parag J.; Bradley, Jeffrey D.; Low, Daniel A.</p> <p>2006-03-01</p> <p>Respiratory <span class="hlt">motion</span> is a significant source of error in conformal radiation therapy for the thorax and upper abdomen. Four-dimensional computed tomography (4D CT) has been proposed to reduce the uncertainty caused by internal respiratory organ <span class="hlt">motion</span>. A 4D CT dataset is retrospectively reconstructed at various stages of a respiratory cycle. An important tool for 4D treatment planning is deformable image registration. An inverse consistent image registration is used to <span class="hlt">model</span> lung <span class="hlt">motion</span> from one respiratory stage to another during a breathing cycle. This diffeomorphic registration jointly estimates the forward and reverse transformations providing more accurate correspondence between two images. Registration results and <span class="hlt">modeled</span> <span class="hlt">motions</span> in the lung are shown for three example respiratory stages. The results demonstrate that the consistent image registration satisfactorily <span class="hlt">models</span> the large <span class="hlt">motions</span> in the lung, providing a useful tool for 4D planning and delivering.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://eric.ed.gov/?q=Cricket&pg=4&id=EJ578229','ERIC'); return false;" href="https://eric.ed.gov/?q=Cricket&pg=4&id=EJ578229"><span><span class="hlt">Modelling</span> the Projectile <span class="hlt">Motion</span> of a Cricket Ball.</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Coutis, Peter</p> <p>1998-01-01</p> <p>Presents the equations of <span class="hlt">motion</span> governing the trajectory of a cricket ball subject to a linear drag force. Uses a perturbation expansion technique to solve the resulting trajectory equation for the range of a cricket ball struck into the outfield. (Author/ASK)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=Equation+AND+trajectory&pg=4&id=EJ578229','ERIC'); return false;" href="http://eric.ed.gov/?q=Equation+AND+trajectory&pg=4&id=EJ578229"><span><span class="hlt">Modelling</span> the Projectile <span class="hlt">Motion</span> of a Cricket Ball.</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Coutis, Peter</p> <p>1998-01-01</p> <p>Presents the equations of <span class="hlt">motion</span> governing the trajectory of a cricket ball subject to a linear drag force. Uses a perturbation expansion technique to solve the resulting trajectory equation for the range of a cricket ball struck into the outfield. (Author/ASK)</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li class="active"><span>17</span></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_17 --> <div id="page_18" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li class="active"><span>18</span></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="341"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013fmer.book..187M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013fmer.book..187M"><span>Estimating Internal Respiratory <span class="hlt">Motion</span> from Respiratory Surrogate Signals Using Correspondence <span class="hlt">Models</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>McClelland, Jamie</p> <p></p> <p>It is often difficult or impossible to directly monitor the respiratory <span class="hlt">motion</span> of the tumour and other internal anatomy during RT treatment. Implanted markers can be used, but this involves an invasive procedure and has a number of other associated risks and problems. An alternative option is to use a correspondence <span class="hlt">model</span>. This <span class="hlt">models</span> the relationship between a respiratory surrogate signal(s), such as spirometry or the displacement of the skin surface, and the <span class="hlt">motion</span> of the internal anatomy. Such a <span class="hlt">model</span> allows the internal <span class="hlt">motion</span> to be estimated from the surrogate signal(s), which can be easily monitored during RT treatment. The correspondence <span class="hlt">model</span> is constructed prior to RT treatment. Imaging data is simultaneously acquired with the surrogate signal(s), and the internal <span class="hlt">motion</span> is measured from the imaging data, e.g. using deformable image registration. A correspondence <span class="hlt">model</span> is then fit relating the internal <span class="hlt">motion</span> to the surrogate signal(s). This can then be used during treatment to estimate the internal <span class="hlt">motion</span> from the surrogate signal(s). This chapter reviews the most popular correspondence <span class="hlt">models</span> that have been used in the literature, as well as the different surrogate signals, types of imaging data used to measure the internal <span class="hlt">motion</span>, and fitting methods used to fit the correspondence <span class="hlt">model</span> to the data.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27187958','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27187958"><span>Spatio-temporal Rich <span class="hlt">Model</span> Based Video Steganalysis on Cross Sections of <span class="hlt">Motion</span> Vector Planes.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Tasdemir, Kasim; Kurugollu, Fatih; Sezer, Sakir</p> <p>2016-05-11</p> <p>A rich <span class="hlt">model</span> based <span class="hlt">motion</span> vector steganalysis benefiting from both temporal and spatial correlations of <span class="hlt">motion</span> vectors is proposed in this work. The proposed steganalysis method has a substantially superior detection accuracy than the previous methods, even the targeted ones. The improvement in detection accuracy lies in several novel approaches introduced in this work. Firstly, it is shown that there is a strong correlation, not only spatially but also temporally, among neighbouring <span class="hlt">motion</span> vectors for longer distances. Therefore, temporal <span class="hlt">motion</span> vector dependency along side the spatial dependency is utilized for rigorous <span class="hlt">motion</span> vector steganalysis. Secondly, unlike the filters previously used, which were heuristically designed against a specific <span class="hlt">motion</span> vector steganography, a diverse set of many filters which can capture aberrations introduced by various <span class="hlt">motion</span> vector steganography methods is used. The variety and also the number of the filter kernels are substantially more than that of used in previous ones. Besides that, filters up to fifth order are employed whereas the previous methods use at most second order filters. As a result of these, the proposed system captures various decorrelations in a wide spatio-temporal range and provides a better cover <span class="hlt">model</span>. The proposed method is tested against the most prominent <span class="hlt">motion</span> vector steganalysis and steganography methods. To the best knowledge of the authors, the experiments section has the most comprehensive tests in <span class="hlt">motion</span> vector steganalysis field including five stego and seven steganalysis methods. Test results show that the proposed method yields around 20% detection accuracy increase in low payloads and 5% in higher payloads.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28113715','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28113715"><span>Spatio-temporal Rich <span class="hlt">Model</span> Based Video Steganalysis on Cross Sections of <span class="hlt">Motion</span> Vector Planes.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Tasdemir, Kasim; Kurugollu, Fatih; Sezer, Sakir</p> <p>2016-05-11</p> <p>A rich <span class="hlt">model</span> based <span class="hlt">motion</span> vector steganalysis benefiting from both temporal and spatial correlations of <span class="hlt">motion</span> vectors is proposed in this work. The proposed steganalysis method has a substantially superior detection accuracy than the previous methods, even the targeted ones. The improvement in detection accuracy lies in several novel approaches introduced in this work. Firstly, it is shown that there is a strong correlation, not only spatially but also temporally, among neighbouring <span class="hlt">motion</span> vectors for longer distances. Therefore, temporal <span class="hlt">motion</span> vector dependency along side the spatial dependency is utilized for rigorous <span class="hlt">motion</span> vector steganalysis. Secondly, unlike the filters previously used, which were heuristically designed against a specific <span class="hlt">motion</span> vector steganography, a diverse set of many filters which can capture aberrations introduced by various <span class="hlt">motion</span> vector steganography methods is used. The variety and also the number of the filter kernels are substantially more than that of used in previous ones. Besides that, filters up to fifth order are employed whereas the previous methods use at most second order filters. As a result of these, the proposed system captures various decorrelations in a wide spatio-temporal range and provides a better cover <span class="hlt">model</span>. The proposed method is tested against the most prominent <span class="hlt">motion</span> vector steganalysis and steganography methods. To the best knowledge of the authors, the experiments section has the most comprehensive tests in <span class="hlt">motion</span> vector steganalysis field including five stego and seven steganalysis methods. Test results show that the proposed method yields around 20% detection accuracy increase in low payloads and 5% in higher payloads.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27570108','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27570108"><span>An improved <span class="hlt">model</span> of <span class="hlt">motion</span>-related signal changes in fMRI.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Patriat, Rémi; Reynolds, Richard C; Birn, Rasmus M</p> <p>2017-01-01</p> <p>Head <span class="hlt">motion</span> is a significant source of noise in the estimation of functional connectivity from resting-state functional MRI (rs-fMRI). Current strategies to reduce this noise include image realignment, censoring time points corrupted by <span class="hlt">motion</span>, and including <span class="hlt">motion</span> realignment parameters and their derivatives as additional nuisance regressors in the general linear <span class="hlt">model</span>. However, this nuisance regression approach assumes that the <span class="hlt">motion</span>-induced signal changes are linearly related to the estimated realignment parameters, which is not always the case. In this study we develop an improved <span class="hlt">model</span> of <span class="hlt">motion</span>-related signal changes, where nuisance regressors are formed by first rotating and translating a single brain volume according to the estimated <span class="hlt">motion</span>, re-registering the data, and then performing a principal components analysis (PCA) on the resultant time series of both moved and re-registered data. We show that these "<span class="hlt">Motion</span> Simulated (MotSim)" regressors account for significantly greater fraction of variance, result in higher temporal signal-to-noise, and lead to functional connectivity estimates that are less affected by <span class="hlt">motion</span> compared to the most common current approach of using the realignment parameters and their derivatives as nuisance regressors. This improvement should lead to more accurate estimates of functional connectivity, particularly in populations where <span class="hlt">motion</span> is prevalent, such as patients and young children.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/22499274','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/22499274"><span>SU-E-J-163: A Biomechanical Lung <span class="hlt">Model</span> for Respiratory <span class="hlt">Motion</span> Study</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Liu, X; Belcher, AH; Grelewicz, Z; Wiersma, RD</p> <p>2015-06-15</p> <p>Purpose: This work presents a biomechanical <span class="hlt">model</span> to investigate the complex respiratory <span class="hlt">motion</span> for the lung tumor tracking in radiosurgery by computer simulation. Methods: The <span class="hlt">models</span> include networked massspring-dampers to describe the tumor <span class="hlt">motion</span>, different types of surrogate signals, and the force generated by the diaphragm. Each mass-springdamper has the same mechanical structure and each <span class="hlt">model</span> can have different numbers of mass-spring-dampers. Both linear and nonlinear stiffness parameters were considered, and the damping ratio was tuned in a range so that the tumor <span class="hlt">motion</span> was over-damped (no natural tumor oscillation occurs without force from the diaphragm). The simulation was run by using ODE45 (ordinary differential equations by Runge-Kutta method) in MATLAB, and all time courses of <span class="hlt">motions</span> and inputs (force) were generated and compared. Results: The curvature of the <span class="hlt">motion</span> time courses around their peaks was sensitive to the damping ratio. Therefore, the damping ratio can be determined based on the clinical data of a high sampling rate. The peak values of different signals and the time the peaks occurred were compared, and it was found that the diaphragm force had a time lead over the tumor <span class="hlt">motion</span>, and the lead time (0.1–0.4 seconds) depended on the distance between the tumor and the diaphragm. Conclusion: We reported a <span class="hlt">model</span> based analysis approach for the spatial and temporal relation between the <span class="hlt">motion</span> of the lung tumor and the surrogate signals. Due to the phase lead of the diaphragm in comparing with the lung tumor <span class="hlt">motion</span>, the measurement of diaphragm <span class="hlt">motion</span> (or its electromyography signal) can be used as a beam gating signal in radiosurgery, and it can also be an additional surrogate signal for better tumor <span class="hlt">motion</span> tracking. The research is funded by the American Cancer Society (ACS) grant. The grant name is: Frameless SRS Based on Robotic Head <span class="hlt">Motion</span> Cancellation. The grant number is: RSG-13-313-01-CCE.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/5196273','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/5196273"><span>Basic simple <span class="hlt">modeling</span> of balloting <span class="hlt">motion</span> of railgun projectiles. Technical report</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Chu, S.H.</p> <p>1991-07-01</p> <p>This is the second of three basic reports dealing with the in-bore balloting <span class="hlt">motion</span> of a projectile launched in an electromagnetic railgun. The first report addressed axial projectile <span class="hlt">motion</span> without cocking and was titled A Basic Single <span class="hlt">Model</span> of In-bore <span class="hlt">Motion</span> of Railgun Projectiles. Understanding the inbore <span class="hlt">motion</span> of a projectile is important to its design and its ability to hit a target with some effectiveness. Analysis of in-bore <span class="hlt">motion</span> is a complicated problem since many parameters are involved and the interacting relationships between them must be determined. To make the problem easier to understand, it was analyzed on several levels beginning with the basic simple <span class="hlt">model</span> which computed only the axial <span class="hlt">motion</span> and followed by more complicated <span class="hlt">models</span> in the upper analysis levels that included as many lateral forces and gun tube vibration effects as possible. This report deals with the second basic or zero level of balloting analysis. A basic simple <span class="hlt">model</span> considering only the effect of the propulsion force, the friction force of the armature, and the clearance between the projectile and the barrel is presented. The computation of the axial projectile <span class="hlt">motion</span> with a certain cocking angle is the goal of this analysis. Equations of <span class="hlt">motion</span> are derived and solved. A sample computation with available data is performed and the results plotted to give a clearer understanding of balloting action.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/16092091','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/16092091"><span>In vitro <span class="hlt">models</span> of <span class="hlt">multiple</span> system atrophy.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Stefanova, Nadia; Reindl, Markus; Poewe, Werner; Wenning, Gregor K</p> <p>2005-08-01</p> <p>alpha-Synuclein represents the major constituent of oligodendroglial cytoplasmic inclusions, the hallmark lesion of <span class="hlt">multiple</span> system atrophy (MSA), a progressive disorder that is associated with selective degenerative cell loss in basal ganglia, cerebellum, brainstem, and spinal cord. The role of abnormal alpha-synuclein aggregation in oligodendroglial cells is still obscure, in particular, whether alpha-synuclein might impair oligodendroglial and, secondarily, neuronal integrity of those cells in the diseased brain. In an attempt to answer some of these questions, we have developed an "in vitro <span class="hlt">model</span> of MSA" by expressing the wild-type or C-terminally truncated form of alpha-synuclein in glial cell cultures. With this simplified system, we have demonstrated that alpha-synuclein significantly affects the survival of glia and its vulnerability to environmental stress, which might represent a major step in the pathogenesis of MSA.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19940025620','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19940025620"><span><span class="hlt">Multiple</span> Concentric Cylinder <span class="hlt">Model</span> (MCCM) user's guide</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Williams, Todd O.; Pindera, Marek-Jerzy</p> <p>1994-01-01</p> <p>A user's guide for the computer program mccm.f is presented. The program is based on a recently developed solution methodology for the inelastic response of an arbitrarily layered, concentric cylinder assemblage under thermomechanical loading which is used to <span class="hlt">model</span> the axisymmetric behavior of unidirectional metal matrix composites in the presence of various microstructural details. These details include the layered morphology of certain types of ceramic fibers, as well as <span class="hlt">multiple</span> fiber/matrix interfacial layers recently proposed as a means of reducing fabrication-induced, and in-service, residual stress. The computer code allows efficient characterization and evaluation of new fibers and/or new coating systems on existing fibers with a minimum of effort, taking into account inelastic and temperature-dependent properties and different morphologies of the fiber and the interfacial region. It also facilitates efficient design of engineered interfaces for unidirectional metal matrix composites.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4491628','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4491628"><span>Embodied learning of a generative neural <span class="hlt">model</span> for biological <span class="hlt">motion</span> perception and inference</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Schrodt, Fabian; Layher, Georg; Neumann, Heiko; Butz, Martin V.</p> <p>2015-01-01</p> <p>Although an action observation network and mirror neurons for understanding the actions and intentions of others have been under deep, interdisciplinary consideration over recent years, it remains largely unknown how the brain manages to map visually perceived biological <span class="hlt">motion</span> of others onto its own motor system. This paper shows how such a mapping may be established, even if the biologically <span class="hlt">motion</span> is visually perceived from a new vantage point. We introduce a learning artificial neural network <span class="hlt">model</span> and evaluate it on full body <span class="hlt">motion</span> tracking recordings. The <span class="hlt">model</span> implements an embodied, predictive inference approach. It first learns to correlate and segment multimodal sensory streams of own bodily <span class="hlt">motion</span>. In doing so, it becomes able to anticipate <span class="hlt">motion</span> progression, to complete missing modal information, and to self-generate learned <span class="hlt">motion</span> sequences. When biological <span class="hlt">motion</span> of another person is observed, this self-knowledge is utilized to recognize similar <span class="hlt">motion</span> patterns and predict their progress. Due to the relative encodings, the <span class="hlt">model</span> shows strong robustness in recognition despite observing rather large varieties of body morphology and posture dynamics. By additionally equipping the <span class="hlt">model</span> with the capability to rotate its visual frame of reference, it is able to deduce the visual perspective onto the observed person, establishing full consistency to the embodied self-<span class="hlt">motion</span> encodings by means of active inference. In further support of its neuro-cognitive plausibility, we also <span class="hlt">model</span> typical bistable perceptions when crucial depth information is missing. In sum, the introduced neural <span class="hlt">model</span> proposes a solution to the problem of how the human brain may establish correspondence between observed bodily <span class="hlt">motion</span> and its own motor system, thus offering a mechanism that supports the development of mirror neurons. PMID:26217215</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26217215','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26217215"><span>Embodied learning of a generative neural <span class="hlt">model</span> for biological <span class="hlt">motion</span> perception and inference.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Schrodt, Fabian; Layher, Georg; Neumann, Heiko; Butz, Martin V</p> <p>2015-01-01</p> <p>Although an action observation network and mirror neurons for understanding the actions and intentions of others have been under deep, interdisciplinary consideration over recent years, it remains largely unknown how the brain manages to map visually perceived biological <span class="hlt">motion</span> of others onto its own motor system. This paper shows how such a mapping may be established, even if the biologically <span class="hlt">motion</span> is visually perceived from a new vantage point. We introduce a learning artificial neural network <span class="hlt">model</span> and evaluate it on full body <span class="hlt">motion</span> tracking recordings. The <span class="hlt">model</span> implements an embodied, predictive inference approach. It first learns to correlate and segment multimodal sensory streams of own bodily <span class="hlt">motion</span>. In doing so, it becomes able to anticipate <span class="hlt">motion</span> progression, to complete missing modal information, and to self-generate learned <span class="hlt">motion</span> sequences. When biological <span class="hlt">motion</span> of another person is observed, this self-knowledge is utilized to recognize similar <span class="hlt">motion</span> patterns and predict their progress. Due to the relative encodings, the <span class="hlt">model</span> shows strong robustness in recognition despite observing rather large varieties of body morphology and posture dynamics. By additionally equipping the <span class="hlt">model</span> with the capability to rotate its visual frame of reference, it is able to deduce the visual perspective onto the observed person, establishing full consistency to the embodied self-<span class="hlt">motion</span> encodings by means of active inference. In further support of its neuro-cognitive plausibility, we also <span class="hlt">model</span> typical bistable perceptions when crucial depth information is missing. In sum, the introduced neural <span class="hlt">model</span> proposes a solution to the problem of how the human brain may establish correspondence between observed bodily <span class="hlt">motion</span> and its own motor system, thus offering a mechanism that supports the development of mirror neurons.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24060706','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24060706"><span>Cell speed is independent of force in a mathematical <span class="hlt">model</span> of amoeboidal cell <span class="hlt">motion</span> with random switching terms.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Dallon, J C; Evans, E J; Grant, Christopher P; Smith, W V</p> <p>2013-11-01</p> <p>In this paper the <span class="hlt">motion</span> of a single cell is <span class="hlt">modeled</span> as a nucleus and <span class="hlt">multiple</span> integrin based adhesion sites. Numerical simulations and analysis of the <span class="hlt">model</span> indicate that when the stochastic nature of the adhesion sites is a memoryless and force independent random process, the cell speed is independent of the force these adhesion sites exert on the cell. Furthermore, understanding the dynamics of the attachment and detachment of the adhesion sites is key to predicting cell speed. We introduce a differential equation describing the cell <span class="hlt">motion</span> and then introduce a conjecture about the expected drift of the cell, the expected average velocity relation conjecture. Using Markov chain theory, we analyze our conjecture in the context of a related (but simpler) <span class="hlt">model</span> of cell <span class="hlt">motion</span>, and then numerically compare the results for the simpler <span class="hlt">model</span> and the full differential equation <span class="hlt">model</span>. We also heuristically describe the relationship between the simplified and full <span class="hlt">models</span> as well as provide a discussion of the biological significance of these results. Copyright © 2013 Elsevier Inc. All rights reserved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5242735','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5242735"><span>Mathematical <span class="hlt">Modeling</span> and Evaluation of Human <span class="hlt">Motions</span> in Physical Therapy Using Mixture Density Neural Networks</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Vakanski, A; Ferguson, JM; Lee, S</p> <p>2016-01-01</p> <p>Objective The objective of the proposed research is to develop a methodology for <span class="hlt">modeling</span> and evaluation of human <span class="hlt">motions</span>, which will potentially benefit patients undertaking a physical rehabilitation therapy (e.g., following a stroke or due to other medical conditions). The ultimate aim is to allow patients to perform home-based rehabilitation exercises using a sensory system for capturing the <span class="hlt">motions</span>, where an algorithm will retrieve the trajectories of a patient’s exercises, will perform data analysis by comparing the performed <span class="hlt">motions</span> to a reference <span class="hlt">model</span> of prescribed <span class="hlt">motions</span>, and will send the analysis results to the patient’s physician with recommendations for improvement. Methods The <span class="hlt">modeling</span> approach employs an artificial neural network, consisting of layers of recurrent neuron units and layers of neuron units for estimating a mixture density function over the spatio-temporal dependencies within the human <span class="hlt">motion</span> sequences. Input data are sequences of <span class="hlt">motions</span> related to a prescribed exercise by a physiotherapist to a patient, and recorded with a <span class="hlt">motion</span> capture system. An autoencoder subnet is employed for reducing the dimensionality of captured sequences of human <span class="hlt">motions</span>, complemented with a mixture density subnet for probabilistic <span class="hlt">modeling</span> of the <span class="hlt">motion</span> data using a mixture of Gaussian distributions. Results The proposed neural network architecture produced a <span class="hlt">model</span> for sets of human <span class="hlt">motions</span> represented with a mixture of Gaussian density functions. The mean log-likelihood of observed sequences was employed as a performance metric in evaluating the consistency of a subject’s performance relative to the reference dataset of <span class="hlt">motions</span>. A publically available dataset of human <span class="hlt">motions</span> captured with Microsoft Kinect was used for validation of the proposed method. Conclusion The article presents a novel approach for <span class="hlt">modeling</span> and evaluation of human <span class="hlt">motions</span> with a potential application in home-based physical therapy and rehabilitation. The described approach</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011PhDT........64V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011PhDT........64V"><span>Architecture in <span class="hlt">motion</span>: A <span class="hlt">model</span> for music composition</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Variego, Jorge Elias</p> <p>2011-12-01</p> <p>Speculations regarding the relationship between music and architecture go back to the very origins of these disciplines. Throughout history, these links have always reaffirmed that music and architecture are analogous art forms that only diverge in their object of study. In the 1 st c. BCE Vitruvius conceived Architecture as "one of the most inclusive and universal human activities" where the architect should be educated in all the arts, having a vast knowledge in history, music and philosophy. In the 18th c., the German thinker Johann Wolfgang von Goethe, described Architecture as "frozen music". More recently, in the 20th c., Iannis Xenakis studied the similar structuring principles between Music and Architecture creating his own "<span class="hlt">models</span>" of musical composition based on mathematical principles and geometric constructions. The goal of this document is to propose a compositional method that will function as a translator between the acoustical properties of a room and music, to facilitate the creation of musical works that will not only happen within an enclosed space but will also intentionally interact with the space. Acoustical measurements of rooms such as reverberation time, frequency response and volume will be measured and systematically organized in correspondence with orchestrational parameters. The musical compositions created after the proposed <span class="hlt">model</span> are evocative of the spaces on which they are based. They are meant to be performed in any space, not exclusively in the one where the acoustical measurements were obtained. The visual component of architectural design is disregarded; the room is considered a musical instrument, with its particular sound qualities and resonances. Compositions using the proposed <span class="hlt">model</span> will not result as sonified shapes, they will be musical works literally "tuned" to a specific space. This Architecture in <span class="hlt">motion</span> is an attempt to adopt scientific research to the service of a creative activity and to let the aural properties of</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2004PMB....49.5357W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2004PMB....49.5357W"><span>A finite state <span class="hlt">model</span> for respiratory <span class="hlt">motion</span> analysis in image guided radiation therapy</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wu, Huanmei; Sharp, Gregory C.; Salzberg, Betty; Kaeli, David; Shirato, Hiroki; Jiang, Steve B.</p> <p>2004-12-01</p> <p>Effective image guided radiation treatment of a moving tumour requires adequate information on respiratory <span class="hlt">motion</span> characteristics. For margin expansion, beam tracking and respiratory gating, the tumour <span class="hlt">motion</span> must be quantified for pretreatment planning and monitored on-line. We propose a finite state <span class="hlt">model</span> for respiratory <span class="hlt">motion</span> analysis that captures our natural understanding of breathing stages. In this <span class="hlt">model</span>, a regular breathing cycle is represented by three line segments, exhale, end-of-exhale and inhale, while abnormal breathing is represented by an irregular breathing state. In addition, we describe an on-line implementation of this <span class="hlt">model</span> in one dimension. We found this <span class="hlt">model</span> can accurately characterize a wide variety of patient breathing patterns. This <span class="hlt">model</span> was used to describe the respiratory <span class="hlt">motion</span> for 23 patients with peak-to-peak <span class="hlt">motion</span> greater than 7 mm. The average root mean square error over all patients was less than 1 mm and no patient has an error worse than 1.5 mm. Our <span class="hlt">model</span> provides a convenient tool to quantify respiratory <span class="hlt">motion</span> characteristics, such as patterns of frequency changes and amplitude changes, and can be applied to internal or external <span class="hlt">motion</span>, including internal tumour position, abdominal surface, diaphragm, spirometry and other surrogates.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19770023806','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19770023806"><span>A trade-off analysis design tool. Aircraft interior noise-<span class="hlt">motion</span>/passenger satisfaction <span class="hlt">model</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Jacobson, I. D.</p> <p>1977-01-01</p> <p>A design tool was developed to enhance aircraft passenger satisfaction. The effect of aircraft interior <span class="hlt">motion</span> and noise on passenger comfort and satisfaction was <span class="hlt">modelled</span>. Effects of individual aircraft noise sources were accounted for, and the impact of noise on passenger activities and noise levels to safeguard passenger hearing were investigated. The <span class="hlt">motion</span> noise effect <span class="hlt">models</span> provide a means for tradeoff analyses between noise and <span class="hlt">motion</span> variables, and also provide a framework for optimizing noise reduction among noise sources. Data for the <span class="hlt">models</span> were collected onboard commercial aircraft flights and specially scheduled tests.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27686701','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27686701"><span>GPU accelerated dynamic respiratory <span class="hlt">motion</span> <span class="hlt">model</span> correction for MRI-guided cardiac interventions.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Xu, Robert; Wright, Graham A</p> <p>2016-11-01</p> <p>The use of pre-procedural magnetic resonance (MR) roadmap images for interventional guidance has limited anatomical accuracy due to intra-procedural respiratory <span class="hlt">motion</span> of the heart. Therefore, the objective of this study is to explore the use of a rapidly updated dynamic <span class="hlt">motion</span> <span class="hlt">model</span> to correct for respiratory <span class="hlt">motion</span> induced errors during MRI-guided cardiac interventions. The motivation for the proposed technique is to improve the accuracy of MRI guidance by taking advantage of the anatomical context provided by the high resolution prior images and the respiratory <span class="hlt">motion</span> information present in a series of realtime MR images. We implemented a GPU accelerated image registration algorithm to derive the respiratory <span class="hlt">motion</span> information and used the resulting transformation parameters to update an adaptive <span class="hlt">motion</span> <span class="hlt">model</span> once every heart cycle. In the subsequent heart cycle, the dynamic <span class="hlt">motion</span> <span class="hlt">model</span> could be used to predict the respiratory <span class="hlt">motion</span> and provide a <span class="hlt">motion</span> estimate to realign the prior volume with the realtime MR image. This iterative update and prediction process is then continuously repeated. The GPU accelerated image registration algorithm could be completed in an average of 176.9 ± 14.0 ms, which is 139× faster than a CPU implementation. Thus, it was feasible to update the dynamic <span class="hlt">model</span> once every heart cycle. The proposed dynamic <span class="hlt">model</span> was also able to improve the registration accuracy from 86.0 ± 7.5% to 93.0 ± 3.3% in case of variable breathing patterns, as evaluated by the dice similarity coefficient of the left ventricular border overlap between the prior and realtime images. The feasibility of a dynamic <span class="hlt">motion</span> correction framework was demonstrated. The resulting improvements may lead to more accurate MRI-guided cardiac interventions in the future. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4125347','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4125347"><span>A novel channel selection method for <span class="hlt">multiple</span> <span class="hlt">motion</span> classification using high-density electromyography</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p></p> <p>2014-01-01</p> <p>Background Selecting an appropriate number of surface electromyography (EMG) channels with desired classification performance and determining the optimal placement of EMG electrodes would be necessary and important in practical myoelectric control. In previous studies, several methods such as sequential forward selection (SFS) and Fisher-Markov selector (FMS) have been used to select the appropriate number of EMG channels for a control system. These exiting methods are dependent on either EMG features and/or classification algorithms, which means that when using different channel features or classification algorithm, the selected channels would be changed. In this study, a new method named multi-class common spatial pattern (MCCSP) was proposed for EMG selection in EMG pattern-recognition-based movement classification. Since MCCSP is independent on specific EMG features and classification algorithms, it would be more convenient for channel selection in developing an EMG control system than the exiting methods. Methods The performance of the proposed MCCSP method in selecting some optimal EMG channels (designated as a subset) was assessed with high-density EMG recordings from twelve mildly-impaired traumatic brain injury (TBI) patients. With the MCCSP method, a subset of EMG channels was selected and then used for <span class="hlt">motion</span> classification with pattern recognition technique. In order to justify the performance of the MCCSP method against different electrode configurations, features and classification algorithms, two electrode configurations (unipolar and bipolar) as well as two EMG feature sets and two types of pattern recognition classifiers were considered in the study, respectively. And the performance of the proposed MCCSP method was compared with that of two exiting channel selection methods (SFS and FMS) in EMG control system. Results The results showed that in comparison with the previously used SFS and FMS methods, the newly proposed MCCSP method had better</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012SPIE.8316E..0CW','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012SPIE.8316E..0CW"><span><span class="hlt">Model</span>-based risk assessment for <span class="hlt">motion</span> effects in 3D radiotherapy of lung tumors</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Werner, René; Ehrhardt, Jan; Schmidt-Richberg, Alexander; Handels, Heinz</p> <p>2012-02-01</p> <p>Although 4D CT imaging becomes available in an increasing number of radiotherapy facilities, 3D imaging and planning is still standard in current clinical practice. In particular for lung tumors, respiratory <span class="hlt">motion</span> is a known source of uncertainty and should be accounted for during radiotherapy planning - which is difficult by using only a 3D planning CT. In this contribution, we propose applying a statistical lung <span class="hlt">motion</span> <span class="hlt">model</span> to predict patients' <span class="hlt">motion</span> patterns and to estimate dosimetric <span class="hlt">motion</span> effects in lung tumor radiotherapy if only 3D images are available. Being generated based on 4D CT images of patients with unimpaired lung <span class="hlt">motion</span>, the <span class="hlt">model</span> tends to overestimate lung tumor <span class="hlt">motion</span>. It therefore promises conservative risk assessment regarding tumor dose coverage. This is exemplarily evaluated using treatment plans of lung tumor patients with different tumor <span class="hlt">motion</span> patterns and for two treatment modalities (conventional 3D conformal radiotherapy and step-&- shoot intensity modulated radiotherapy). For the test cases, 4D CT images are available. Thus, also a standard registration-based 4D dose calculation is performed, which serves as reference to judge plausibility of the modelbased 4D dose calculation. It will be shown that, if combined with an additional simple patient-specific breathing surrogate measurement (here: spirometry), the <span class="hlt">model</span>-based dose calculation provides reasonable risk assessment of respiratory <span class="hlt">motion</span> effects.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70020109','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70020109"><span>Stochastic point-source <span class="hlt">modeling</span> of ground <span class="hlt">motions</span> in the Cascadia region</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Atkinson, G.M.; Boore, D.M.</p> <p>1997-01-01</p> <p>A stochastic <span class="hlt">model</span> is used to develop preliminary ground <span class="hlt">motion</span> relations for the Cascadia region for rock sites. The <span class="hlt">model</span> parameters are derived from empirical analyses of seismographic data from the Cascadia region. The <span class="hlt">model</span> is based on a Brune point-source characterized by a stress parameter of 50 bars. The <span class="hlt">model</span> predictions are compared to ground-<span class="hlt">motion</span> data from the Cascadia region and to data from large earthquakes in other subduction zones. The point-source simulations match the observations from moderate events (M 100 km). The discrepancy at large magnitudes suggests further work on <span class="hlt">modeling</span> finite-fault effects and regional attenuation is warranted. In the meantime, the preliminary equations are satisfactory for predicting <span class="hlt">motions</span> from events of M < 7 and provide conservative estimates of <span class="hlt">motions</span> from larger events at distances less than 100 km.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28664198','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28664198"><span>3D <span class="hlt">Motion</span> <span class="hlt">Modeling</span> and Reconstruction of Left Ventricle Wall in Cardiac MRI.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Yang, Dong; Wu, Pengxiang; Tan, Chaowei; Pohl, Kilian M; Axel, Leon; Metaxas, Dimitris</p> <p>2017-06-01</p> <p>The analysis of left ventricle (LV) wall <span class="hlt">motion</span> is a critical step for understanding cardiac functioning mechanisms and clinical diagnosis of ventricular diseases. We present a novel approach for 3D <span class="hlt">motion</span> <span class="hlt">modeling</span> and analysis of LV wall in cardiac magnetic resonance imaging (MRI). First, a fully convolutional network (FCN) is deployed to initialize myocardium contours in 2D MR slices. Then, we propose an image registration algorithm to align MR slices in space and minimize the undesirable <span class="hlt">motion</span> artifacts from inconsistent respiration. Finally, a 3D deformable <span class="hlt">model</span> is applied to recover the shape and <span class="hlt">motion</span> of myocardium wall. Utilizing the proposed approach, we can visually analyze 3D LV wall <span class="hlt">motion</span>, evaluate cardiac global function, and diagnose ventricular diseases.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li class="active"><span>18</span></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_18 --> <div id="page_19" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li class="active"><span>19</span></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="361"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/23774464','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/23774464"><span><span class="hlt">Multiple</span> routes to mental animation: language and functional relations drive <span class="hlt">motion</span> processing for static images.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Coventry, Kenny R; Christophel, Thomas B; Fehr, Thorsten; Valdés-Conroy, Berenice; Herrmann, Manfred</p> <p>2013-08-01</p> <p>When looking at static visual images, people often exhibit mental animation, anticipating visual events that have not yet happened. But what determines when mental animation occurs? Measuring mental animation using localized brain function (visual <span class="hlt">motion</span> processing in the middle temporal and middle superior temporal areas, MT+), we demonstrated that animating static pictures of objects is dependent both on the functionally relevant spatial arrangement that objects have with one another (e.g., a bottle above a glass vs. a glass above a bottle) and on the linguistic judgment to be made about those objects (e.g., "Is the bottle above the glass?" vs. "Is the bottle bigger than the glass?"). Furthermore, we showed that mental animation is driven by functional relations and language separately in the right hemisphere of the brain but conjointly in the left hemisphere. Mental animation is not a unitary construct; the predictions humans make about the visual world are driven flexibly, with hemispheric asymmetry in the routes to MT+ activation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016PhDT........39D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016PhDT........39D"><span>Lung <span class="hlt">Motion</span> <span class="hlt">Model</span> Validation Experiments, Free-Breathing Tissue Densitometry, and Ventilation Mapping using Fast Helical CT Imaging</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Dou, Hsiang-Tai</p> <p></p> <p>The uncertainties due to respiratory <span class="hlt">motion</span> present significant challenges to accurate characterization of cancerous tissues both in terms of imaging and treatment. Currently available clinical lung imaging techniques are subject to inferior image quality and incorrect <span class="hlt">motion</span> estimation, with consequences that can systematically impact the downstream treatment delivery and outcome. The main objective of this thesis is the development of the techniques of fast helical computed tomography (CT) imaging and deformable image registration for the radiotherapy applications in accurate breathing <span class="hlt">motion</span> <span class="hlt">modeling</span>, lung tissue density <span class="hlt">modeling</span> and ventilation imaging. Fast helical CT scanning was performed on 64-slice CT scanner using the shortest available gantry rotation time and largest pitch value such that scanning of the thorax region amounts to just two seconds, which is less than typical breathing cycle in humans. The scanning was conducted under free breathing condition. Any portion of the lung anatomy undergoing such scanning protocol would be irradiated for only a quarter second, effectively removing any <span class="hlt">motion</span> induced image artifacts. The resulting CT data were pristine volumetric images that record the lung tissue position and density in a fraction of the breathing cycle. Following our developed protocol, <span class="hlt">multiple</span> fast helical CT scans were acquired to sample the tissue positions in different breathing states. To measure the tissue displacement, deformable image registration was performed that registers the non-reference images to the reference one. In <span class="hlt">modeling</span> breathing <span class="hlt">motion</span>, external breathing surrogate signal was recorded synchronously with the CT image slices. This allowed for the tissue-specific displacement to be <span class="hlt">modeled</span> as parametrization of the recorded breathing signal using the 5D lung <span class="hlt">motion</span> <span class="hlt">model</span>. To assess the accuracy of the <span class="hlt">motion</span> <span class="hlt">model</span> in describing tissue position change, the <span class="hlt">model</span> was used to simulate the original high-pitch helical CT scan</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.dtic.mil/docs/citations/ADA237938','DTIC-ST'); return false;" href="http://www.dtic.mil/docs/citations/ADA237938"><span>Basic Simple <span class="hlt">Modeling</span> of Balloting <span class="hlt">Motion</span> of Railgun Projectiles.</span></a></p> <p><a target="_blank" href="http://www.dtic.mil/">DTIC Science & Technology</a></p> <p></p> <p>1991-07-01</p> <p>force of the armature, and the clearance between the projectile and the barrel is presented. The computation of the axial projectile <span class="hlt">motion</span> with a...system 3 2 Barrel and projectile package configuration showing propulsion and 6 interacting forces 3 Rail current versus time 9 4 Cocking angle versus...the projectile. It affects the lateral impact of the projectile on the barrel , muzzle jump, intermediate and terminal ballistics and, consequently</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24479258','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24479258"><span><span class="hlt">Motion</span> sickness: an evolutionary and genetic basis for the negative reinforcement <span class="hlt">model</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Knox, Glenn W</p> <p>2014-01-01</p> <p>It has been theorized that <span class="hlt">motion</span> sickness evolved as a negative reinforcement system which terminates <span class="hlt">motion</span> involving postural instability and/or sensory conflict. A hypothetical example is provided by a "thought experiment" whereby protohominids are in a tree looking for food. Selection pressure results when the organisms that have an aversion to <span class="hlt">motion</span>-producing sensory conflict do not venture out too far on the tree limbs and therefore tend to survive. In order to support an evolutionary <span class="hlt">model</span> for <span class="hlt">motion</span> sickness there must be evidence for genetic and/or heritable predisposition. The present study involves a retrospective literature review which reveals abundant evidence for genetic/heritable factors in <span class="hlt">motion</span> sickness. Examples include genetic polymorphism of the alpha-2-adrenergic receptor, which has been shown to increase susceptibility to <span class="hlt">motion</span> sickness, examination of family trees revealing heritable <span class="hlt">motion</span> sickness susceptibility, evidence indicating that Asians are hyper-susceptible to <span class="hlt">motion</span> sickness, and twin studies, just to mention a few. Thus, the theory of heritable negative reinforcement as a basis for <span class="hlt">motion</span> sickness is supported by extensive evidence in the medical literature. This theory is compared and contrasted with other theories. Further areas for research are suggested.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2005SPIE.5960.1343Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2005SPIE.5960.1343Y"><span>Scalable complexity-distortion <span class="hlt">model</span> for fast <span class="hlt">motion</span> estimation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yi, Xiaoquan; Ling, Nam</p> <p>2005-07-01</p> <p>Recently established international video coding standard H.264/AVC and the upcoming standard on scalable video coding (SVC) bring part of the solution to high compression ratio requirement and heterogeneity requirement. However, these algorithms have unbearable complexities for real-time encoding. Therefore, there is an important challenge to reduce encoding complexity, preferably in a scalable manner. <span class="hlt">Motion</span> estimation and <span class="hlt">motion</span> compensation techniques provide significant coding gain but are the most time-intensive parts in an encoder system. They present tremendous research challenges to design a flexible, rate-distortion optimized, yet computationally efficient encoder, especially for various applications. In this paper, we present a scalable <span class="hlt">motion</span> estimation framework for complexitydistortion consideration. We propose a new progressive initial search (PIS) method to generate an accurate initial search point, followed by a fast search method, which can greatly benefit from the tighter bounds of the PIS. Such approach offers not only significant speedup but also an optimal distortion performance for a given complexity constrain. We analyze the relationship between computational complexity and distortion (C-D) through probabilistic distance measure extending from the complexity and distortion theory. A configurable complexity quantization parameter (Q) is introduced. Simulation results demonstrate that the proposed scalable complexity-distortion framework enables video encoder to conveniently adjust its complexity while providing best possible services.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015SPIE.9795E..1HX','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015SPIE.9795E..1HX"><span>Research on <span class="hlt">motion</span> <span class="hlt">model</span> for the hypersonic boost-glide aircraft</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Xu, Shenda; Wu, Jing; Wang, Xueying</p> <p>2015-11-01</p> <p>A <span class="hlt">motion</span> <span class="hlt">model</span> for the hypersonic boost-glide aircraft(HBG) was proposed in this paper, which also analyzed the precision of <span class="hlt">model</span> through simulation. Firstly the trajectory of HBG was analyzed, and a scheme which divide the trajectory into two parts then build the <span class="hlt">motion</span> <span class="hlt">model</span> on each part. Secondly a restrained <span class="hlt">model</span> of boosting stage and a restrained <span class="hlt">model</span> of J2 perturbation were established, and set up the observe <span class="hlt">model</span>. Finally the analysis of simulation results show the feasible and high-accuracy of the <span class="hlt">model</span>, and raise a expectation for intensive research.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3614340','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3614340"><span>Body-worn <span class="hlt">motion</span> sensors detect balance and gait deficits in people with <span class="hlt">multiple</span> sclerosis who have normal walking speed</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Spain, R.I.; George, R.J.; Salarian, A.; Mancini, M.; Wagner, J.M.; Horak, F.B.; Bourdette, D.</p> <p>2013-01-01</p> <p>While balance and gait limitations are hallmarks of <span class="hlt">multiple</span> sclerosis (MS), standard stopwatch-timed measures practical for use in the clinic are insensitive in minimally affected patients. This prevents early detection and intervention for mobility problems. The study sought to determine if body-worn sensors could detect differences in balance and gait between people with MS with normal walking speeds and healthy controls. Thirty-one MS and twenty-eight age- and sex-matched control subjects were tested using body-worn sensors both during quiet stance and gait (Timed Up and Go test, TUG). Results were compared to stopwatch-timed measures. Stopwatch durations of the TUG and Timed 25 Foot Walk tests were not significantly different between groups. However, during quiet stance with eyes closed, people with MS had significantly greater sway acceleration amplitude than controls (p = 0.02). During gait, people with MS had greater trunk angular range of <span class="hlt">motion</span> in roll (medio-lateral flexion, p = 0.017) and yaw (axial rotation, p = 0.026) planes. Turning duration through 180° was also longer in MS (p = 0.031). Thus, body-worn <span class="hlt">motion</span> sensors detected mobility differences between MS and healthy controls when traditional timed tests could not. This portable technology provides objective and quantitative mobility data previously not obtainable in the clinic, and may prove a useful outcome measure for early mobility changes in MS. PMID:22277368</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27908022','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27908022"><span>Sampled-data-based consensus and containment control of <span class="hlt">multiple</span> harmonic oscillators: A <span class="hlt">motion</span>-planning approach.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Liu, Yongfang; Zhao, Yu; Chen, Guanrong</p> <p>2016-11-01</p> <p>This paper studies the distributed consensus and containment problems for a group of harmonic oscillators with a directed communication topology. First, for consensus without a leader, a class of distributed consensus protocols is designed by using <span class="hlt">motion</span> planning and Pontryagin's principle. The proposed protocol only requires relative information measurements at the sampling instants, without requiring information exchange over the sampled interval. By using stability theory and the properties of stochastic matrices, it is proved that the distributed consensus problem can be solved in the <span class="hlt">motion</span> planning framework. Second, for the case with <span class="hlt">multiple</span> leaders, a class of distributed containment protocols is developed for followers such that their positions and velocities can ultimately converge to the convex hull formed by those of the leaders. Compared with the existing consensus algorithms, a remarkable advantage of the proposed sampled-data-based protocols is that the sampling periods, communication topologies and control gains are all decoupled and can be separately designed, which relaxes many restrictions in controllers design. Finally, some numerical examples are given to illustrate the effectiveness of the analytical results.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016Chaos..26k6303L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016Chaos..26k6303L"><span>Sampled-data-based consensus and containment control of <span class="hlt">multiple</span> harmonic oscillators: A <span class="hlt">motion</span>-planning approach</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Liu, Yongfang; Zhao, Yu; Chen, Guanrong</p> <p>2016-11-01</p> <p>This paper studies the distributed consensus and containment problems for a group of harmonic oscillators with a directed communication topology. First, for consensus without a leader, a class of distributed consensus protocols is designed by using <span class="hlt">motion</span> planning and Pontryagin's principle. The proposed protocol only requires relative information measurements at the sampling instants, without requiring information exchange over the sampled interval. By using stability theory and the properties of stochastic matrices, it is proved that the distributed consensus problem can be solved in the <span class="hlt">motion</span> planning framework. Second, for the case with <span class="hlt">multiple</span> leaders, a class of distributed containment protocols is developed for followers such that their positions and velocities can ultimately converge to the convex hull formed by those of the leaders. Compared with the existing consensus algorithms, a remarkable advantage of the proposed sampled-data-based protocols is that the sampling periods, communication topologies and control gains are all decoupled and can be separately designed, which relaxes many restrictions in controllers design. Finally, some numerical examples are given to illustrate the effectiveness of the analytical results.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1994SPIE.2299..169K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1994SPIE.2299..169K"><span>Statistical methods for analysis of coordination of chest wall <span class="hlt">motion</span> using optical reflectance imaging of <span class="hlt">multiple</span> markers</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kenyon, C. M.; Ghezzo, R. H.; Cala, S. J.; Ferrigno, Giancarlo; Pedotti, Antonio; Macklem, P. T.; Rochester, D. F.</p> <p>1994-07-01</p> <p>To analyze coordination of chest wall <span class="hlt">motion</span> we have used principle component analysis (PCA) and <span class="hlt">multiple</span> regression analysis (MRA) with respect to spirometry on the displacements of 93 optical reflective markers placed upon the chest wall (CW). Each marker is tracked at 10 Hz with an accuracy of 0.2 mm in each spatial dimension using the ELITE system (IEEE Trans. Biomed. Eng. 11:943-949, 1985). PCA enables the degree of linear coordination between all of the markers to be assessed using the eigenvectors and eigenvalues of the covariance of the matrix of marker displacements in each dimension against time. Thus the number of linear degrees of freedom (DOF) which contribute more than a particular amount to the total variance can be determined and analyzed. MRA with respect to spirometrically measured lung volume changes enables identification of the CW points whose movement correlates best with lung volume. We have used this analysis to compare a quiet breathing sequence with one where tidal volume was increased fourfold involuntarily and show that the number of DOF with eigenvalues accounting for >5% of the covariance increased from 2 to 3. Also the point whose movement correlated best with lung volume changed from halfway down the lower costal margin to a more lateral point at the level of the bottom of the sternum. This quantification of CW coordination may be useful in analysis and staging of many respiratory disorders and is applicable to any nonrigid body <span class="hlt">motion</span> where points can be tracked.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFM.S31C4423B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFM.S31C4423B"><span>Development of Response Spectral Ground <span class="hlt">Motion</span> Prediction Equations from Empirical <span class="hlt">Models</span> for Fourier Spectra and Duration of Ground <span class="hlt">Motion</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bora, S. S.; Scherbaum, F.; Kuehn, N. M.; Stafford, P.; Edwards, B.</p> <p>2014-12-01</p> <p>In a probabilistic seismic hazard assessment (PSHA) framework, it still remains a challenge to adjust ground <span class="hlt">motion</span> prediction equations (GMPEs) for application in different seismological environments. In this context, this study presents a complete framework for the development of a response spectral GMPE easily adjustable to different seismological conditions; and which does not suffer from the technical problems associated with the adjustment in response spectral domain. Essentially, the approach consists of an empirical FAS (Fourier Amplitude Spectrum) <span class="hlt">model</span> and a duration <span class="hlt">model</span> for ground <span class="hlt">motion</span> which are combined within the random vibration theory (RVT) framework to obtain the full response spectral ordinates. Additionally, FAS corresponding to individual acceleration records are extrapolated beyond the frequency range defined by the data using the stochastic FAS <span class="hlt">model</span>, obtained by inversion as described in Edwards & Faeh, (2013). To that end, an empirical <span class="hlt">model</span> for a duration, which is tuned to optimize the fit between RVT based and observed response spectral ordinate, at each oscillator frequency is derived. Although, the main motive of the presented approach was to address the adjustability issues of response spectral GMPEs; comparison, of median predicted response spectra with the other regional <span class="hlt">models</span> indicate that presented approach can also be used as a stand-alone <span class="hlt">model</span>. Besides that, a significantly lower aleatory variability (σ<0.5 in log units) in comparison to other regional <span class="hlt">models</span>, at shorter periods brands it to a potentially viable alternative to the classical regression (on response spectral ordinates) based GMPEs for seismic hazard studies in the near future. The dataset used for the presented analysis is a subset of the recently compiled database RESORCE-2012 across Europe, Middle East and the Mediterranean region.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/23366934','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/23366934"><span>Activity monitoring and <span class="hlt">motion</span> classification of the lizard Chamaeleo jacksonii using <span class="hlt">multiple</span> Doppler radars.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Singh, Aditya; Lee, Scott S K; Butler, Marguerite; Lubecke, Victor</p> <p>2012-01-01</p> <p>We describe a simple, non-contact and efficient tool for monitoring the natural activity of a small lizard (Chamaeleo jacksonii) to yield valuable information about their metabolic activity and energy expenditure. It allows monitoring in a non-confined laboratory environment and uses <span class="hlt">multiple</span> Doppler radars operating at 10.525 GHz. We developed a classification algorithm that can differentiate between fidgeting and locomotion by processing the quadrature baseband signals from the radars. The results have been verified by visual inspection and indicate that the tool could also be used for automated monitoring of the activities of reptiles and other small animals.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4891065','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4891065"><span>Activity Monitoring and <span class="hlt">Motion</span> Classification of the Lizard Chamaeleo jacksonii Using <span class="hlt">Multiple</span> Doppler Radars</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Singh, Aditya; Lee, Scott SK; Butler, Marguerite; Lubecke, Victor</p> <p>2016-01-01</p> <p>We describe a simple, non-contact and efficient tool for monitoring the natural activity of a small lizard (Chamaeleo jacksonii) to yield valuable information about their metabolic activity and energy expenditure. It allows monitoring in a non-confined laboratory environment and uses <span class="hlt">multiple</span> Doppler radars operating at 10.525 GHz. We developed a classification algorithm that can differentiate between fidgeting and locomotion by processing the quadrature baseband signals from the radars. The results have been verified by visual inspection and indicate that the tool could also be used for automated monitoring of the activities of reptiles and other small animals. PMID:23366934</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/22334133','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/22334133"><span>SU-D-17A-03: 5D Respiratory <span class="hlt">Motion</span> <span class="hlt">Model</span> Based Iterative Reconstruction Method for 4D Cone-Beam CT</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Gao, Y; Thomas, D; Low, D; Gao, H</p> <p>2014-06-01</p> <p>Purpose: The purpose of this work is to develop a new iterative reconstruction method for 4D cone-beam CT (CBCT) based on a published time-independent 5D respiratory <span class="hlt">motion</span> <span class="hlt">model</span>. The proposed method will offer a single high-resolution image at a user-selected breathing phase and the 5D <span class="hlt">motion</span> <span class="hlt">model</span> parameters, which could be used to generate the breathing pattern during the CT acquisition. Methods: 5D respiratory <span class="hlt">motion</span> <span class="hlt">model</span> was proposed for accurately <span class="hlt">modeling</span> the <span class="hlt">motion</span> of lung and lung tumor tissues. 4D images are then parameterized by a reference image, measured breathing amplitude, breathing rate, two time-independent vector fields that describe the 5D <span class="hlt">model</span> parameters, and a scalar field that describes the change in HU as a function of breathing amplitude. In contrast with the traditional method of reconstructing <span class="hlt">multiple</span> temporal image phases to reduce respiratory artifact, 5D <span class="hlt">model</span> based method simplify the problem into the reconstruction of a single reference image and the 5D <span class="hlt">motion</span> <span class="hlt">model</span> parameters. The reconstruction formulation of the reference image and scalar and vector fields is a nonlinear least-square optimization problem that consists of solving the reference image and fields alternately, in which the reference image is regularized with the total variation sparsity transform and the vector fields are solved through linearizations regularized by the H1 norm. 2D lung simulations were performed in this proof-of-concept study. Results: The breathing amplitude, its rate, and the corresponding scalar and vector fields were generated from a patient case. Compared with filtered backprojection method and sparsity regularized iterative method for the phase-by-phase reconstruction, the proposed 5D <span class="hlt">motion</span> <span class="hlt">model</span> based method yielded improved image quality. Conclusion: Based on 5D respiratory <span class="hlt">motion</span> <span class="hlt">model</span>, we have developed a new iterative reconstruction method for 4D CBCT that has the potential for improving image quality while providing needed on</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://files.eric.ed.gov/fulltext/EJ1078502.pdf','ERIC'); return false;" href="http://files.eric.ed.gov/fulltext/EJ1078502.pdf"><span>Helping Students Acquainted with <span class="hlt">Multiplication</span> in Rectangular <span class="hlt">Model</span></span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Tasman, Fridgo; den Hertog, Jaap; Zulkardi; Hartono, Yusuf</p> <p>2011-01-01</p> <p>Usually, <span class="hlt">multiplication</span> is introduced to students to represent quantities that come in groups. However there is also rectangular array <span class="hlt">model</span> which is also related to <span class="hlt">multiplication</span>. Barmby et al. (2009) has shown that the rectangular <span class="hlt">model</span> such as array representations encourage students to develop their thinking about <span class="hlt">multiplication</span> as a binary…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EGUGA..17.7110W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EGUGA..17.7110W"><span>Hydrological excitation of polar <span class="hlt">motion</span> by different variables from the GLDAS <span class="hlt">model</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wińska, Małgorzata; Nastula, Jolanta; Salstein, David</p> <p>2015-04-01</p> <p>Continental hydrological loading, by land water, snow, and ice, is an element that is strongly needed for a full understanding of the excitation of polar <span class="hlt">motion</span>. In this study we compute different estimations of hydrological excitation functions of polar <span class="hlt">motion</span> (Hydrological Angular Momentum - HAM) using various variables from the Global Land Data Assimilation System (GLDAS) <span class="hlt">model</span> of the land-based hydrosphere. The main aim of this study is to show the influence of variables from different hydrological processes, including for example: total evapotranspiration, runoff, snowmelt, soil moisture to polar <span class="hlt">motion</span> excitations in seasonal timescale. Hydrological excitation functions of polar <span class="hlt">motion</span>, both global and regional, are determined by using selected variables of these GLDAS realizations. First we compare the timing, spectra and phase diagrams of different regional and global HAMs with each other. Next, we estimate, the hydrological signal in geodetically-observed polar <span class="hlt">motion</span> excitation as a residual by subtracting the atmospheric - AAM (pressure + wind) and oceanic - OAM (bottom pressure + currents) contributions. Finally, the hydrological excitations are compared to these hydrological signal from the observed polar <span class="hlt">motion</span> excitation series residuals. The results help us understand the relative importance for polar <span class="hlt">motion</span> excitation of the individual variables from different hydrological processes, based on hydrological <span class="hlt">modeling</span>. This method can allows us to estimate how well the polar <span class="hlt">motion</span> excitation budget in the seasonal spectral ranges can be closed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/16671302','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/16671302"><span>Robust ego-<span class="hlt">motion</span> estimation and 3-D <span class="hlt">model</span> refinement using surface parallax.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Agrawal, Amit; Chellappa, Rama</p> <p>2006-05-01</p> <p>We present an iterative algorithm for robustly estimating the ego-<span class="hlt">motion</span> and refining and updating a coarse depth map using parametric surface parallax <span class="hlt">models</span> and brightness derivatives extracted from an image pair. Given a coarse depth map acquired by a range-finder or extracted from a digital elevation map (DEM), ego-<span class="hlt">motion</span> is estimated by combining a global ego-<span class="hlt">motion</span> constraint and a local brightness constancy constraint. Using the estimated camera <span class="hlt">motion</span> and the available depth estimate, <span class="hlt">motion</span> of the three-dimensional (3-D) points is compensated. We utilize the fact that the resulting surface parallax field is an epipolar field, and knowing its direction from the previous <span class="hlt">motion</span> estimates, estimate its magnitude and use it to refine the depth map estimate. The parallax magnitude is estimated using a constant parallax <span class="hlt">model</span> (CPM) which assumes a smooth parallax field and a depth based parallax <span class="hlt">model</span> (DBPM), which <span class="hlt">models</span> the parallax magnitude using the given depth map. We obtain confidence measures for determining the accuracy of the estimated depth values which are used to remove regions with potentially incorrect depth estimates for robustly estimating ego-<span class="hlt">motion</span> in subsequent iterations. Experimental results using both synthetic and real data (both indoor and outdoor sequences) illustrate the effectiveness of the proposed algorithm.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19830006625','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19830006625"><span>A heuristic mathematical <span class="hlt">model</span> for the dynamics of sensory conflict and <span class="hlt">motion</span> sickness</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Oman, C. M.</p> <p>1982-01-01</p> <p>The etiology of <span class="hlt">motion</span> sickness is now usually explained in terms of a qualitatively formulated sensory conflict hypothesis. By consideration of the information processing task faced by the central nervous system in estimating body spatial orientation and in controlling active body movement using an internal <span class="hlt">model</span> referenced control strategy, a mathematical <span class="hlt">model</span> for sensory conflict generation is developed. The <span class="hlt">model</span> postulates a major dynamic functional role for sensory conflict signals in movement control, as well as in sensory motor adaptation. It accounts for the role of active movement in creating <span class="hlt">motion</span> sickness symptoms in some experimental circumstances, and in alleviating them in others. The relationship between <span class="hlt">motion</span> sickness produced by sensory rearrangement and that resulting from external <span class="hlt">motion</span> disturbances is explicitly defined. A nonlinear conflict averaging <span class="hlt">model</span> describes dynamic aspects of experimentally observed subjective discomfort sensation, and suggests resulting behavior.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19830004577','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19830004577"><span>A heuristic mathematical <span class="hlt">model</span> for the dynamics of sensory conflict and <span class="hlt">motion</span> sickness</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Oman, C. M.</p> <p>1980-01-01</p> <p>The etiology of <span class="hlt">motion</span> sickness is explained in terms of a qualitatively formulated sensory conflict hypothesis. By consideration of the information processing task faced by the central nervous system in estimating body spatial orientation and in controlling active body movement using an internal <span class="hlt">model</span> referenced control strategy, a mathematical <span class="hlt">model</span> for sensory conflict generation is developed. The <span class="hlt">model</span> postulates a major dynamic functional role for sensory conflict signals in movement control, as well as in sensory-motor adaptation. It accounts for the role of active movement in creating <span class="hlt">motion</span> sickness symptoms in some experimental circumstances, and in alleviating them in others. The relationship between <span class="hlt">motion</span> sickness produced by sensory rearrangement and that resulting from external <span class="hlt">motion</span> disturbances is explicitly defined. A nonlinear conflict averaging <span class="hlt">model</span> is proposed which describes dynamic aspects of experimentally observed subjective discomfort sensation, and suggests resulting behaviors.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015SPIE.9635E..22G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015SPIE.9635E..22G"><span><span class="hlt">Model</span>-based <span class="hlt">multiple</span> patterning layout decomposition</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Guo, Daifeng; Tian, Haitong; Du, Yuelin; Wong, Martin D. F.</p> <p>2015-10-01</p> <p>As one of the most promising next generation lithography technologies, <span class="hlt">multiple</span> patterning lithography (MPL) plays an important role in the attempts to keep in pace with 10 nm technology node and beyond. With feature size keeps shrinking, it has become impossible to print dense layouts within one single exposure. As a result, MPL such as double patterning lithography (DPL) and triple patterning lithography (TPL) has been widely adopted. There is a large volume of literature on DPL/TPL layout decomposition, and the current approach is to formulate the problem as a classical graph-coloring problem: Layout features (polygons) are represented by vertices in a graph G and there is an edge between two vertices if and only if the distance between the two corresponding features are less than a minimum distance threshold value dmin. The problem is to color the vertices of G using k colors (k = 2 for DPL, k = 3 for TPL) such that no two vertices connected by an edge are given the same color. This is a rule-based approach, which impose a geometric distance as a minimum constraint to simply decompose polygons within the distance into different masks. It is not desired in practice because this criteria cannot completely capture the behavior of the optics. For example, it lacks of sufficient information such as the optical source characteristics and the effects between the polygons outside the minimum distance. To remedy the deficiency, a <span class="hlt">model</span>-based layout decomposition approach to make the decomposition criteria base on simulation results was first introduced at SPIE 2013.1 However, the algorithm1 is based on simplified assumption on the optical simulation <span class="hlt">model</span> and therefore its usage on real layouts is limited. Recently AMSL2 also proposed a <span class="hlt">model</span>-based approach to layout decomposition by iteratively simulating the layout, which requires excessive computational resource and may lead to sub-optimal solutions. The approach2 also potentially generates too many stiches. In this</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li class="active"><span>19</span></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_19 --> <div id="page_20" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li class="active"><span>20</span></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="381"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19920030322&hterms=Hawaii+Plate+Tectonics&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3DHawaii%2BPlate%2BTectonics','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19920030322&hterms=Hawaii+Plate+Tectonics&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3DHawaii%2BPlate%2BTectonics"><span>No-net-rotation <span class="hlt">model</span> of current plate velocities incorporating plate <span class="hlt">motion</span> <span class="hlt">model</span> NUVEL-1</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Argus, Donald F.; Gordon, Richard G.</p> <p>1991-01-01</p> <p>NNR-NUVEL1 is presented which is a <span class="hlt">model</span> of plate velocities relative to the unique reference frame defined by requiring no-net-rotation of the lithosphere while constraining relative plate velocities to equal those in global plate <span class="hlt">motion</span> <span class="hlt">model</span> NUVEL-1 (DeMets et al., 1990). In NNR-NUVEL1, the Pacific plate rotates in a right-handed sense relative to the no-net-rotation reference frame at 0.67 deg/m.y. about 63 deg S, 107 deg E. At Hawaii the Pacific plate moves relative to the no-net-rotation reference frame at 70 mm/yr, which is 25 mm/yr slower than the Pacific plate moves relative to the hotspots. Differences between NNR-NUVEL1 and HS2-NUVEL1 are described. The no-net-rotation reference frame differs significantly from the hotspot reference frame. If the difference between reference frames is caused by <span class="hlt">motion</span> of the hotspots relative to a mean-mantle reference frame, then hotspots beneath the Pacific plate move with coherent <span class="hlt">motion</span> towards the east-southeast. Alternatively, the difference between reference frames can show that the uniform drag, no-net-torque reference frame, which is kinematically equivalent to the no-net-rotation reference frame, is based on a dynamically incorrect premise.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=bolt+AND+analysis&pg=5&id=EJ895491','ERIC'); return false;" href="http://eric.ed.gov/?q=bolt+AND+analysis&pg=5&id=EJ895491"><span>Nested Logit <span class="hlt">Models</span> for <span class="hlt">Multiple</span>-Choice Item Response Data</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Suh, Youngsuk; Bolt, Daniel M.</p> <p>2010-01-01</p> <p>Nested logit item response <span class="hlt">models</span> for <span class="hlt">multiple</span>-choice data are presented. Relative to previous <span class="hlt">models</span>, the new <span class="hlt">models</span> are suggested to provide a better approximation to <span class="hlt">multiple</span>-choice items where the application of a solution strategy precedes consideration of response options. In practice, the <span class="hlt">models</span> also accommodate collapsibility across all…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017JGeod.tmp..108S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017JGeod.tmp..108S"><span>Long-term prediction of polar <span class="hlt">motion</span> using a combined SSA and ARMA <span class="hlt">model</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Shen, Yi; Guo, Jinyun; Liu, Xin; Kong, Qiaoli; Guo, Linxi; Li, Wang</p> <p>2017-09-01</p> <p>To meet the need for real-time and high-accuracy predictions of polar <span class="hlt">motion</span> (PM), the singular spectrum analysis (SSA) and the autoregressive moving average (ARMA) <span class="hlt">model</span> are combined for short- and long-term PM prediction. According to the SSA results for PM and the SSA prediction algorithm, the principal components of PM were predicted by SSA, and the remaining components were predicted by the ARMA <span class="hlt">model</span>. In applying this proposed method, <span class="hlt">multiple</span> sets of PM predictions were made with lead times of two years, based on an IERS 08 C04 series. The observations and predictions of the principal components correlated well, and the SSA + ARMA <span class="hlt">model</span> effectively predicted the PM. For 360-day lead time predictions, the root-mean-square errors (RMSEs) of PMx and PMy were 20.67 and 20.42 mas, respectively, which were less than the 24.46 and 24.78 mas predicted by IERS Bulletin A. The RMSEs of PMx and PMy in the 720-day lead time predictions were 28.61 and 27.95 mas, respectively.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1999PhDT........23T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1999PhDT........23T"><span><span class="hlt">Modeling</span> and characterization of <span class="hlt">multiple</span> coupled lines</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tripathi, Alok</p> <p>1999-10-01</p> <p>A configuration-oriented circuit <span class="hlt">model</span> for <span class="hlt">multiple</span> coupled lines in an inhomogeneous medium is developed and presented in this thesis. This circuit <span class="hlt">model</span> consists of a network of uncoupled transmission lines and is readily <span class="hlt">modeled</span> with simulation tools like LIBRA© and SPICE ©. It provides an equivalent circuit representation which is simple and topologically meaningful as compared to the <span class="hlt">model</span> based on modal decomposition. The configuration-oriented <span class="hlt">model</span> is derived by decomposing the immittance matrices associated with an n coupled line 2n-port system. Time- and frequency- domain simulations of typical coupled line multiports are included to exemplify the utility of the <span class="hlt">model</span>. The <span class="hlt">model</span> is useful for the simulation and design of general single and multilayer coupled line components, such as filters and couplers, and for the investigation of signal integrity issues including crosstalk in interconnects associated with high speed digital and mixed signal electronic modules and packages. It is shown that multiconductor lossless structures in an inhomogeneous medium can be characterized by multiport time-domain reflection (MR) measurements. A synthesis technique of an equivalent lossless (non-dispersive) uniform multiconductor n coupled lines (UMCL) 2n-port system from the measured discrete time-domain reflection response is presented. This procedure is based on the decomposition of the characteristic immittance matrices of the UMCL in terms of partial mode immittance matrices. The decomposition scheme leads to the discrete transition matrix function of a UMCL 2n-port system. This in turn establishes a relationship between the normal-mode parameters of the UMCL and the measured impulse reflection and transmission response. Equivalence between the synthesis procedure presented in this thesis and the solution of a special form of an algebraic Riccati matrix equation whose solution can lead to the normal-mode parameters and a real termination network is illustrated. In</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014OAP....27...41B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014OAP....27...41B"><span><span class="hlt">Modelling</span> of <span class="hlt">Motion</span> of Bodies Near Triangular Lagrangian Points</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bobrov, O. A.</p> <p></p> <p>In this paper, we consider a system of three bodies connected by gravity, two of which are of comparable mass (the Sun and Jupiter), and the third is negligible and it is located in one of the triangular Lagrange points (restricted 3 - body problem). We used the equations of <span class="hlt">motion</span> in a planar coordinate system that rotates together with massive bodies. Several programs have been written in the programming environment Pascal ABC, in order to build the trajectory of a small body, to indicate the osculating orbit around a massive body, to display equipotential surfaces.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4441867','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4441867"><span>Construction and evaluation of an integrated dynamical <span class="hlt">model</span> of visual <span class="hlt">motion</span> perception</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Dosher, Barbara Anne; Lu, Zhong-Lin</p> <p>2015-01-01</p> <p>Although numerous <span class="hlt">models</span> describe the individual neural mechanisms that may be involved in the perception of visual <span class="hlt">motion</span>, few of them have been constructed to take arbitrary stimuli and map them to a <span class="hlt">motion</span> percept. Here, we propose an integrated dynamical <span class="hlt">motion</span> <span class="hlt">model</span> (IDM), which is sufficiently general to handle diverse moving stimuli, yet sufficiently precise to account for a wide-ranging set of empirical observations made on a family of random dot kinematograms. In particular, we constructed <span class="hlt">models</span> of the cortical areas involved in <span class="hlt">motion</span> detection, <span class="hlt">motion</span> integration and perceptual decision. We analyzed their parameters through dynamical simulations and numerical continuation to constrain their proper ranges. Then, empirical data from a family of random dot kinematograms experiments with systematically varying direction distribution, presentation duration and stimulus size, were used to evaluate our <span class="hlt">model</span> and estimate corresponding <span class="hlt">model</span> parameters. The resulting <span class="hlt">model</span> provides an excellent account of a demanding set of parametrically varied behavioral effects on <span class="hlt">motion</span> perception, providing both quantitative and qualitative elements of evaluation. PMID:25897511</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/17664561','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/17664561"><span><span class="hlt">Model</span>-based respiratory <span class="hlt">motion</span> compensation for emission tomography image reconstruction.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Reyes, M; Malandain, G; Koulibaly, P M; González-Ballester, M A; Darcourt, J</p> <p>2007-06-21</p> <p>In emission tomography imaging, respiratory <span class="hlt">motion</span> causes artifacts in lungs and cardiac reconstructed images, which lead to misinterpretations, imprecise diagnosis, impairing of fusion with other modalities, etc. Solutions like respiratory gating, correlated dynamic PET techniques, list-mode data based techniques and others have been tested, which lead to improvements over the spatial activity distribution in lungs lesions, but which have the disadvantages of requiring additional instrumentation or the need of discarding part of the projection data used for reconstruction. The objective of this study is to incorporate respiratory <span class="hlt">motion</span> compensation directly into the image reconstruction process, without any additional acquisition protocol consideration. To this end, we propose an extension to the maximum likelihood expectation maximization (MLEM) algorithm that includes a respiratory <span class="hlt">motion</span> <span class="hlt">model</span>, which takes into account the displacements and volume deformations produced by the respiratory <span class="hlt">motion</span> during the data acquisition process. We present results from synthetic simulations incorporating real respiratory <span class="hlt">motion</span> as well as from phantom and patient data.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011TSICE..46..547I','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011TSICE..46..547I"><span>Cardiac <span class="hlt">Motion</span> Analysis Using High-Speed Video Images in a Rat <span class="hlt">Model</span> for Myocardial Infarction</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ishii, Idaku; Okuda, Toshikazu; Nie, Yuman; Takaki, Takeshi; Orito, Kensuke; Tanaka, Akane; Matsuda, Hiroshi</p> <p></p> <p>In this study, we performed a cardiac <span class="hlt">motion</span> analysis by using 1000-frames per second (fps) stereo images to capture the three-dimensional <span class="hlt">motion</span> of small color markers in a rat heart. This method of recording cardiac <span class="hlt">motion</span> could quantify the rate of change in the myocardial area, which indicated localized myocardial activity of rhythmic expansion and contraction. We analyzed the three-dimensional <span class="hlt">motion</span> distributions in a rat <span class="hlt">model</span> for myocardial infarction, in which the heart rate was 4 times/s or more. In the analysis, we spatiotemporally quantified the characteristic cardiac <span class="hlt">motion</span> in ischemic heart diseases and found that infarction due to ischemia in the rat heart was spread around the left ventricle.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013PMB....58.2085P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013PMB....58.2085P"><span>Cardiac <span class="hlt">motion</span> compensation and resolution <span class="hlt">modeling</span> in simultaneous PET-MR: a cardiac lesion detection study</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Petibon, Y.; Ouyang, J.; Zhu, X.; Huang, C.; Reese, T. G.; Chun, S. Y.; Li, Q.; El Fakhri, G.</p> <p>2013-04-01</p> <p>Cardiac <span class="hlt">motion</span> and partial volume effects (PVE) are two of the main causes of image degradation in cardiac PET. <span class="hlt">Motion</span> generates artifacts and blurring while PVE lead to erroneous myocardial activity measurements. Newly available simultaneous PET-MR scanners offer new possibilities in cardiac imaging as MRI can assess wall contractility while collecting PET perfusion data. In this perspective, we develop a list-mode iterative reconstruction framework incorporating both tagged-MR derived non-rigid myocardial wall <span class="hlt">motion</span> and position dependent detector point spread function (PSF) directly into the PET system matrix. In this manner, our algorithm performs both <span class="hlt">motion</span> ‘deblurring’ and PSF deconvolution while reconstructing images with all available PET counts. The proposed methods are evaluated in a beating non-rigid cardiac phantom whose hot myocardial compartment contains small transmural and non-transmural cold defects. In order to accelerate imaging time, we investigate collecting full and half k-space tagged MR data to obtain tagged volumes that are registered using non-rigid B-spline registration to yield wall <span class="hlt">motion</span> information. Our experimental results show that tagged-MR based <span class="hlt">motion</span> correction yielded an improvement in defect/myocardium contrast recovery of 34-206% as compared to <span class="hlt">motion</span> uncorrected studies. Likewise, lesion detectability improved by respectively 115-136% and 62-235% with MR-based <span class="hlt">motion</span> compensation as compared to gating and no <span class="hlt">motion</span> correction and made it possible to distinguish non-transmural from transmural defects, which has clinical significance given the inherent limitations of current single modality imaging in identifying the amount of residual ischemia. The incorporation of PSF <span class="hlt">modeling</span> within the framework of MR-based <span class="hlt">motion</span> compensation significantly improved defect/myocardium contrast recovery (5.1-8.5%, p < 0.01) and defect detectability (39-56%, p < 0.01). No statistical difference was found in PET contrast and lesion</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012SPIE.8402E..03T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012SPIE.8402E..03T"><span>Uncertainty preserving patch-based online <span class="hlt">modeling</span> for 3D <span class="hlt">model</span> acquisition and integration from passive <span class="hlt">motion</span> imagery</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tang, Hao; Chang, Peng; Molina, Edgardo; Zhu, Zhigang</p> <p>2012-06-01</p> <p>In both military and civilian applications, abundant data from diverse sources captured on airborne platforms are often available for a region attracting interest. Since the data often includes <span class="hlt">motion</span> imagery streams collected from <span class="hlt">multiple</span> platforms flying at different altitudes, with sensors of different field of views (FOVs), resolutions, frame rates and spectral bands, it is imperative that a cohesive site <span class="hlt">model</span> encompassing all the information can be quickly built and presented to the analysts. In this paper, we propose to develop an Uncertainty Preserving Patch-based Online <span class="hlt">Modeling</span> System (UPPOMS) leading towards the automatic creation and updating of a cohesive, geo-registered, uncertaintypreserving, efficient 3D site terrain <span class="hlt">model</span> from passive imagery with varying field-of-views and phenomenologies. The proposed UPPOMS has the following technical thrusts that differentiate our approach from others: (1) An uncertaintypreserved, patch-based 3D <span class="hlt">model</span> is generated, which enables the integration of images captured with a mixture of NFOV and WFOV and/or visible and infrared <span class="hlt">motion</span> imagery sensors. (2) Patch-based stereo matching and multi-view 3D integration are utilized, which are suitable for scenes with many low texture regions, particularly in mid-wave infrared images. (3) In contrast to the conventional volumetric algorithms, whose computational and storage costs grow exponentially with the amount of input data and the scale of the scene, the proposed UPPOMS system employs an online algorithmic pipeline, and scales well to large amount of input data. Experimental results and discussions of future work will be provided.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2586919','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2586919"><span>Object Segmentation from <span class="hlt">Motion</span> Discontinuities and Temporal Occlusions–A Biologically Inspired <span class="hlt">Model</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Beck, Cornelia; Ognibeni, Thilo; Neumann, Heiko</p> <p>2008-01-01</p> <p>Background Optic flow is an important cue for object detection. Humans are able to perceive objects in a scene using only kinetic boundaries, and can perform the task even when other shape cues are not provided. These kinetic boundaries are characterized by the presence of <span class="hlt">motion</span> discontinuities in a local neighbourhood. In addition, temporal occlusions appear along the boundaries as the object in front covers the background and the objects that are spatially behind it. Methodology/Principal Findings From a technical point of view, the detection of <span class="hlt">motion</span> boundaries for segmentation based on optic flow is a difficult task. This is due to the problem that flow detected along such boundaries is generally not reliable. We propose a <span class="hlt">model</span> derived from mechanisms found in visual areas V1, MT, and MSTl of human and primate cortex that achieves robust detection along <span class="hlt">motion</span> boundaries. It includes two separate mechanisms for both the detection of <span class="hlt">motion</span> discontinuities and of occlusion regions based on how neurons respond to spatial and temporal contrast, respectively. The mechanisms are embedded in a biologically inspired architecture that integrates information of different <span class="hlt">model</span> components of the visual processing due to feedback connections. In particular, mutual interactions between the detection of <span class="hlt">motion</span> discontinuities and temporal occlusions allow a considerable improvement of the kinetic boundary detection. Conclusions/Significance A new <span class="hlt">model</span> is proposed that uses optic flow cues to detect <span class="hlt">motion</span> discontinuities and object occlusion. We suggest that by combining these results for <span class="hlt">motion</span> discontinuities and object occlusion, object segmentation within the <span class="hlt">model</span> can be improved. This idea could also be applied in other <span class="hlt">models</span> for object segmentation. In addition, we discuss how this <span class="hlt">model</span> is related to neurophysiological findings. The <span class="hlt">model</span> was successfully tested both with artificial and real sequences including self and object <span class="hlt">motion</span>. PMID:19043613</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011AGUFM.V53G..03S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AGUFM.V53G..03S"><span><span class="hlt">Motion</span> of Hawaii and Louisville hotspots: Comparision of <span class="hlt">modeling</span> results with new age and paleolatitude data</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Steinberger, B. M.; O'Connor, J. M.; Koppers, A. A.</p> <p>2011-12-01</p> <p>The bend in the Hawaiian-Emperor Chain is often seen as a consequence of Pacific plate <span class="hlt">motion</span> change. Alternatively, it may record a change in <span class="hlt">motion</span> of the Hawaii hotspot, or a combination of both. In order to devise a common reference frame for plate <span class="hlt">motions</span> and flow in the mantle, which is needed to understand plate-mantle interaction, it is important to resolve that issue. Here we contribute towards that goal by comparing predictions of a geodynamic <span class="hlt">model</span> of hotspot <span class="hlt">motion</span> with new age and paleolatitude data from the Hawaiian-Emperor and Louisville chains. These are the two most prominent hotspot tracks on the Pacific plate and hence most suitable to constrain its <span class="hlt">motion</span>. Comparing the age progression along both tracks can tell about the relative <span class="hlt">motion</span> or fixity of the two hotspots, whereas paleo-latitude data ideally can resolve hotspot <span class="hlt">motion</span> relative to the pole. However, their interpretation also needs to consider the possibility of true polar wander -- re-orientation of the entire Earth including the mantle relative to the pole. To <span class="hlt">model</span> hotspot <span class="hlt">motion</span>, we first compute large-scale mantle flow. Mantle density anomalies are inferred from seismic tomography <span class="hlt">models</span>, assuming both density and seismic velocity anomalies are due to temperature anomalies, except in parts of the uppermost mantle (tectosphere) and possibly parts of the lowermost mantle (Large Low Shear Velocity Provinces). Radial mantle viscosity structure is chosen such that it is consistent with mineral physics, and the "Haskell average" inferred from postglacial rebound observations, and the <span class="hlt">model</span> prediction of the geoid and global heat flux agrees well with observations. Time dependence is achieved by considering changes in plate <span class="hlt">motions</span> and geometry as mantle flow boundary conditions, and advecting density anomalies back with the flow. Secondly we compute the <span class="hlt">motion</span> of plume conduits in large-scale flow, assuming conduits are vertical at an initial time, and subsequently move with the flow</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/16102939','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/16102939"><span>On-chip visual perception of <span class="hlt">motion</span>: a bio-inspired connectionist <span class="hlt">model</span> on FPGA.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Torres-Huitzil, César; Girau, Bernard; Castellanos-Sánchez, Claudio</p> <p>2005-01-01</p> <p>Visual <span class="hlt">motion</span> provides useful information to understand the dynamics of a scene to allow intelligent systems interact with their environment. <span class="hlt">Motion</span> computation is usually restricted by real time requirements that need the design and implementation of specific hardware architectures. In this paper, the design of hardware architecture for a bio-inspired neural <span class="hlt">model</span> for <span class="hlt">motion</span> estimation is presented. The <span class="hlt">motion</span> estimation is based on a strongly localized bio-inspired connectionist <span class="hlt">model</span> with a particular adaptation of spatio-temporal Gabor-like filtering. The architecture is constituted by three main modules that perform spatial, temporal, and excitatory-inhibitory connectionist processing. The biomimetic architecture is <span class="hlt">modeled</span>, simulated and validated in VHDL. The synthesis results on a Field Programmable Gate Array (FPGA) device show the potential achievement of real-time performance at an affordable silicon area.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1995SPIE.2501..846S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1995SPIE.2501..846S"><span>Reconstruction-<span class="hlt">model</span>-based snake applied to optimal <span class="hlt">motion</span> contour positioning</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sanson, Henri</p> <p>1995-04-01</p> <p>This paper addresses the problem of optimal positioning of a contour separating two moving regions using snake concepts. After a brief recall of classical snake methodology, an alternative approach is proposed, based on a reconstruction criterion for the regions delimited by the curve, and the use of parametric <span class="hlt">modeling</span> of both the region textures and boundaries. A generic adaptive step gradient algorithm is formulated for solving the curve evolution problem, independently of the <span class="hlt">models</span> used. The method is then more specifically applied to <span class="hlt">motion</span> boundary localization, where the texture of mobile regions is reconstructed by <span class="hlt">motion</span> compensation, using polynomial <span class="hlt">motion</span> <span class="hlt">models</span>. The generic optimization algorithm is applied to <span class="hlt">motion</span> frontiers defined by B- spline curves. Detailed implementation of this method in this particular case is described, and considerations about its behavior are given. Some experimental results are finally reported, attesting the interest of the proposed approach.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012SPIE.8402E..0JL','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012SPIE.8402E..0JL"><span>CMA-HT: a crowd <span class="hlt">motion</span> analysis framework based on heat-transfer analog <span class="hlt">model</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Liang, Yu; Melvin, William; Sritharan, Subramania I.; Fernandes, Shane; Barker, Darrell</p> <p>2012-06-01</p> <p>Crowd <span class="hlt">motion</span> analysis covers the detection, tracking, recognition, and behavior interpretation of target group from persistent surveillance video data. This project is dedicated to investigating a crowd <span class="hlt">motion</span> analysis system based on a heat-transfer-analog <span class="hlt">model</span> (denoted as CMA-HT for simplicity), and a generic <span class="hlt">modeling</span> and simulation framework describing crowd <span class="hlt">motion</span> behavior. CMA-HT is formulated by coupling the statistical analysis of crowd's historical behavior at a given location, geographic information system, and crowd <span class="hlt">motion</span> dynamics. The mathematical derivation of the CMA-HT <span class="hlt">model</span> and the innovative methods involved in the framework's implementation will be discussed in detail. Using the sample video data collected by Central Florida University as benchmark, CMA-HT is employed to measure and identify anomalous personnel or group responses in the video.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010FlDyR..42b5501O','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010FlDyR..42b5501O"><span>A computational study of the dynamic <span class="hlt">motion</span> of a bubble rising in Carreau <span class="hlt">model</span> fluids</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ohta, Mitsuhiro; Yoshida, Yutaka; Sussman, Mark</p> <p>2010-04-01</p> <p>We present the results of three-dimensional direct numerical simulations of the dynamic <span class="hlt">motion</span> of a gas bubble rising in Carreau <span class="hlt">model</span> fluids. The simulations are carried out by a coupled level-set/volume-of-fluid (CLSVOF) method, which combines some of the advantages of the volume-of-fluid (VOF) method with the level-set (LS) method. In our study, it is shown that the <span class="hlt">motion</span> of a rising gas bubble largely depends on the Carreau <span class="hlt">model</span> parameters, n and B (n, the slope of decreasing viscosity and B, time constant). Both the <span class="hlt">model</span> parameters, n and B, have considerable influence on the bubble rise <span class="hlt">motion</span>. Using numerical analysis, we can understand in detail the bubble morphology for non-Newtonian two-phase flow systems. We also discuss bubble rise <span class="hlt">motion</span> in shear-thinning fluids in terms of the effective viscosity, ηeff, the effective Reynolds number, Reeff and the effective Morton number, Meff.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19830008786','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19830008786"><span>A heuristic mathematical <span class="hlt">model</span> for the dynamics of sensory conflict and <span class="hlt">motion</span> sickness</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Oman, C. M.</p> <p>1982-01-01</p> <p>By consideration of the information processing task faced by the central nervous system in estimating body spatial orientation and in controlling active body movement using an internal <span class="hlt">model</span> referenced control strategy, a mathematical <span class="hlt">model</span> for sensory conflict generation is developed. The <span class="hlt">model</span> postulates a major dynamic functional role for sensory conflict signals in movement control, as well as in sensory-motor adaptation. It accounts for the role of active movement in creating <span class="hlt">motion</span> sickness symptoms in some experimental circumstance, and in alleviating them in others. The relationship between <span class="hlt">motion</span> sickness produced by sensory rearrangement and that resulting from external <span class="hlt">motion</span> disturbances is explicitly defined. A nonlinear conflict averaging <span class="hlt">model</span> is proposed which describes dynamic aspects of experimentally observed subjective discomfort sensation, and suggests resulting behaviours. The <span class="hlt">model</span> admits several possibilities for adaptive mechanisms which do not involve internal <span class="hlt">model</span> updating. Further systematic efforts to experimentally refine and validate the <span class="hlt">model</span> are indicated.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015OptEn..54l3108Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015OptEn..54l3108Z"><span>Joint <span class="hlt">motion</span> <span class="hlt">model</span> for local stereo video-matching method</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhang, Jinglin; Bai, Cong; Nezan, Jean-Francois; Cousin, Jean-Gabriel</p> <p>2015-12-01</p> <p>As one branch of stereo matching, video stereo matching becomes more and more significant in computer vision applications. The conventional stereo matching methods for static images would cause flicker-frames and worse matching results. We propose a joint <span class="hlt">motion</span>-based square step (JMSS) method for stereo video matching. The <span class="hlt">motion</span> vector is introduced as one component in the support region building for the raw cost aggregation. Then we aggregate the raw cost along two directions in the support region. Finally, the winner-take-all strategy determines the best disparity under our hypothesis. Experimental results show that the JMSS method not only outperforms other state-of-the-art stereo matching methods on test sequences with abundant movements, but also performs well in some real-world scenes with fixed and moving stereo cameras, respectively, in particular under some extreme conditions of real stereo visions. Additionally, the proposed JMSS method can be implemented in real time, which is superior to other state-of-the-art methods. The time efficiency is also a very important consideration in our algorithm design.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/11534840','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/11534840"><span>Knee surgery assistance: patient <span class="hlt">model</span> construction, <span class="hlt">motion</span> simulation, and biomechanical visualization.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Chen, J X; Wechsler, H; Pullen, J M; Zhu, Y; MacMahon, E B</p> <p>2001-09-01</p> <p>We present a new system that integrates computer graphics, physics-based <span class="hlt">modeling</span>, and interactive visualization to assist knee study and surgical operation. First, we discuss generating patient-specific three-dimensional (3-D) knee <span class="hlt">models</span> from patient's magnetic resonant images (MRIs). The 3-D <span class="hlt">model</span> is obtained by deforming a reference <span class="hlt">model</span> to match the MRI dataset. Second, we present simulating knee <span class="hlt">motion</span> that visualizes patient-specific <span class="hlt">motion</span> data on the patient-specific knee <span class="hlt">model</span>. Third, we introduce visualizing biomechanical information on a patient-specific <span class="hlt">model</span>. The focus is on visualizing contact area, contact forces, and menisci deformation. Traditional methods have difficulty in visualizing knee contact area without using invasive methods. The approach presented here provides an alternative of visualizing the knee contact area and forces without any risk to the patient. Finally, a virtual surgery can be performed. The constructed 3-D knee <span class="hlt">model</span> is the basis of <span class="hlt">motion</span> simulation, biomechanical visualization, and virtual surgery. Knee <span class="hlt">motion</span> simulation determines the knee rotation angles as well as knee contact points. These parameters are used to solve the biomechanical <span class="hlt">model</span>. Our results integrate 3-D construction, <span class="hlt">motion</span> simulation, and biomechanical visualization into one system. Overall, the methodologies here are useful elements for future virtual medical systems where all the components of visualization, automated <span class="hlt">model</span> generation, and surgery simulation come together.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25330424','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25330424"><span>Neural network-based <span class="hlt">motion</span> control of an underactuated wheeled inverted pendulum <span class="hlt">model</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Yang, Chenguang; Li, Zhijun; Cui, Rongxin; Xu, Bugong</p> <p>2014-11-01</p> <p>In this paper, automatic <span class="hlt">motion</span> control is investigated for one of wheeled inverted pendulum (WIP) <span class="hlt">models</span>, which have been widely applied for <span class="hlt">modeling</span> of a large range of two wheeled modern vehicles. First, the underactuated WIP <span class="hlt">model</span> is decomposed into a fully actuated second order subsystem Σa consisting of planar movement of vehicle forward and yaw angular <span class="hlt">motions</span>, and a nonactuated first order subsystem Σb of pendulum <span class="hlt">motion</span>. Due to the unknown dynamics of subsystem Σa and the universal approximation ability of neural network (NN), an adaptive NN scheme has been employed for <span class="hlt">motion</span> control of subsystem Σa . The <span class="hlt">model</span> reference approach has been used whereas the reference <span class="hlt">model</span> is optimized by the finite time linear quadratic regulation technique. The pendulum <span class="hlt">motion</span> in the passive subsystem Σb is indirectly controlled using the dynamic coupling with planar forward <span class="hlt">motion</span> of subsystem Σa , such that satisfactory tracking of a set pendulum tilt angle can be guaranteed. Rigours theoretic analysis has been established, and simulation studies have been performed to demonstrate the developed method.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li class="active"><span>20</span></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_20 --> <div id="page_21" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li class="active"><span>21</span></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="401"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/17076393','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/17076393"><span>An improved observation <span class="hlt">model</span> for super-resolution under affine <span class="hlt">motion</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Rochefort, Gilles; Champagnat, Frédéric; Le Besnerais, Guy; Giovannelli, Jean-François</p> <p>2006-11-01</p> <p>Super-resolution (SR) techniques make use of subpixel shifts between frames in an image sequence to yield higher resolution images. We propose an original observation <span class="hlt">model</span> devoted to the case of nonisometric inter-frame <span class="hlt">motion</span> as required, for instance, in the context of airborne imaging sensors. First, we describe how the main observation <span class="hlt">models</span> used in the SR literature deal with <span class="hlt">motion</span>, and we explain why they are not suited for nonisometric <span class="hlt">motion</span>. Then, we propose an extension of the observation <span class="hlt">model</span> by Elad and Feuer adapted to affine <span class="hlt">motion</span>. This <span class="hlt">model</span> is based on a decomposition of affine transforms into successive shear transforms, each one efficiently implemented by row-by-row or column-by-column one-dimensional affine transforms. We demonstrate on synthetic and real sequences that our observation <span class="hlt">model</span> incorporated in a SR reconstruction technique leads to better results in the case of variable scale <span class="hlt">motions</span> and it provides equivalent results in the case of isometric <span class="hlt">motions</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26495992','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26495992"><span>Identifying and <span class="hlt">modeling</span> <span class="hlt">motion</span> primitives for the hydromedusae Sarsia tubulosa and Aequorea victoria.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Sledge, Isaac; Krieg, Michael; Lipinski, Doug; Mohseni, Kamran</p> <p>2015-10-23</p> <p>The movements of organisms can be thought of as aggregations of <span class="hlt">motion</span> primitives: <span class="hlt">motion</span> segments containing one or more significant actions. Here, we present a means to identify and characterize <span class="hlt">motion</span> primitives from recorded movement data. We address these problems by assuming that the <span class="hlt">motion</span> sequences can be characterized as a series of dynamical-system-based pattern generators. By adopting a nonparametric, Bayesian formalism for learning and simplifying these pattern generators, we arrive at a purely data-driven <span class="hlt">model</span> to automatically identify breakpoints in the movement sequences. We apply this <span class="hlt">model</span> to swimming sequences from two hydromedusa. The first hydromedusa is the prolate Sarsia tubulosa, for which we obtain five <span class="hlt">motion</span> primitives that correspond to bell cavity pressurization, jet formation, jetting, cavity fluid refill, and coasting. The second hydromedusa is the oblate Aequorea victoria, for which we obtain five <span class="hlt">motion</span> primitives that correspond to bell compression, vortex separation, cavity fluid refill, vortex formation, and coasting. Our experimental results indicate that the breakpoints between primitives are correlated with transitions in the bell geometry, vortex formation and shedding, and changes in derived dynamical quantities. These dynamics quantities include terms like pressure, power, drag, and thrust. Such findings suggest that dynamics information is inherently present in the observed <span class="hlt">motions</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5026392','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5026392"><span>4D cone-beam CT reconstruction using multi-organ meshes for sliding <span class="hlt">motion</span> <span class="hlt">modeling</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Zhong, Zichun; Gu, Xuejun; Mao, Weihua; Wang, Jing</p> <p>2016-01-01</p> <p>A simultaneous <span class="hlt">motion</span> estimation and image reconstruction (SMEIR) strategy was proposed for 4D cone-beam CT (4D-CBCT) reconstruction and showed excellent results in both phantom and lung cancer patient studies. In the original SMEIR algorithm, the deformation vector field (DVF) was defined on voxel grid and estimated by enforcing a global smoothness regularization term on the <span class="hlt">motion</span> fields. The objective of this work is to improve the computation efficiency and <span class="hlt">motion</span> estimation accuracy of SMEIR for 4D-CBCT through developing a multi-organ meshing <span class="hlt">model</span>. Feature-based adaptive meshes were generated to reduce the number of unknowns in the DVF estimation and accurately capture the organ shapes and <span class="hlt">motion</span>. Additionally, the discontinuity in the <span class="hlt">motion</span> fields between different organs during respiration was explicitly considered in the multi-organ mesh <span class="hlt">model</span>. This will help with the accurate visualization and <span class="hlt">motion</span> estimation of the tumor on the organ boundaries in 4D-CBCT. To further improve the computational efficiency, a GPU-based parallel implementation was designed. The performance of the proposed algorithm was evaluated on a synthetic sliding <span class="hlt">motion</span> phantom, a 4D NCAT phantom, and four lung cancer patients. The proposed multi-organ mesh based strategy outperformed the conventional Feldkamp–Davis–Kress, iterative total variation minimization, original SMEIR and single meshing method based on both qualitative and quantitative evaluations. PMID:26758496</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016PMB....61..996Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016PMB....61..996Z"><span>4D cone-beam CT reconstruction using multi-organ meshes for sliding <span class="hlt">motion</span> <span class="hlt">modeling</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhong, Zichun; Gu, Xuejun; Mao, Weihua; Wang, Jing</p> <p>2016-02-01</p> <p>A simultaneous <span class="hlt">motion</span> estimation and image reconstruction (SMEIR) strategy was proposed for 4D cone-beam CT (4D-CBCT) reconstruction and showed excellent results in both phantom and lung cancer patient studies. In the original SMEIR algorithm, the deformation vector field (DVF) was defined on voxel grid and estimated by enforcing a global smoothness regularization term on the <span class="hlt">motion</span> fields. The objective of this work is to improve the computation efficiency and <span class="hlt">motion</span> estimation accuracy of SMEIR for 4D-CBCT through developing a multi-organ meshing <span class="hlt">model</span>. Feature-based adaptive meshes were generated to reduce the number of unknowns in the DVF estimation and accurately capture the organ shapes and <span class="hlt">motion</span>. Additionally, the discontinuity in the <span class="hlt">motion</span> fields between different organs during respiration was explicitly considered in the multi-organ mesh <span class="hlt">model</span>. This will help with the accurate visualization and <span class="hlt">motion</span> estimation of the tumor on the organ boundaries in 4D-CBCT. To further improve the computational efficiency, a GPU-based parallel implementation was designed. The performance of the proposed algorithm was evaluated on a synthetic sliding <span class="hlt">motion</span> phantom, a 4D NCAT phantom, and four lung cancer patients. The proposed multi-organ mesh based strategy outperformed the conventional Feldkamp-Davis-Kress, iterative total variation minimization, original SMEIR and single meshing method based on both qualitative and quantitative evaluations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012PMB....57N.411C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012PMB....57N.411C"><span>Development of a novel experimental <span class="hlt">model</span> to investigate radiobiological implications of respiratory <span class="hlt">motion</span> in advanced radiotherapy</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Cole, Aidan J.; McGarry, Conor K.; Butterworth, Karl T.; Prise, Kevin M.; O'Sullivan, Joe M.; Hounsell, Alan R.</p> <p>2012-11-01</p> <p>Respiratory <span class="hlt">motion</span> introduces complex spatio-temporal variations in the dosimetry of radiotherapy. There is a paucity of literature investigating the radiobiological consequences of intrafraction <span class="hlt">motion</span> and concerns regarding the impact of movement when applied to cancer cell lines in vitro exist. We have addressed this by developing a novel <span class="hlt">model</span> which accurately replicates respiratory <span class="hlt">motion</span> under experimental conditions to allow clinically relevant irradiation of cell lines. A bespoke phantom and motor driven moving platform was adapted to accommodate flasks containing medium and cells in order to replicate respiratory <span class="hlt">motion</span> using varying frequencies and amplitude settings. To study this effect on cell survival in vitro, dose response curves were determined for human lung cancer cell lines H1299 and H460 exposed to a uniform 6 MV radiation field under moving or stationary conditions. Cell survival curves showed no significant difference between irradiation at different dose points for these cell lines in the presence or absence of <span class="hlt">motion</span>. These data indicate that <span class="hlt">motion</span> of unshielded cells in vitro does not affect cell survival in the presence of uniform irradiation. This <span class="hlt">model</span> provides a novel research platform to investigate the radiobiological consequences of respiratory <span class="hlt">motion</span> in radiotherapy.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20110020642&hterms=tidal+power&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dtidal%2Bpower','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20110020642&hterms=tidal+power&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dtidal%2Bpower"><span>Observing and <span class="hlt">Modeling</span> Long-Period Tidal Variations in Polar <span class="hlt">Motion</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Gross, Richard S.; Dickman, S. R.</p> <p>2011-01-01</p> <p>By exchanging angular momentum with the solid Earth, ocean tides cause the Earth's rotation to change. While hydrodynamic tide <span class="hlt">models</span> have been used to study the effect of ocean tides on polar <span class="hlt">motion</span>, it is shown here that none of the published <span class="hlt">models</span> can fully account for the observed variations. An empirical ocean tide <span class="hlt">model</span> is therefore determined by fitting periodic terms at the tidal frequencies to polar <span class="hlt">motion</span> excitation observations, from which atmospheric and non-tidal oceanic effects were removed. While the empirical ocean tide <span class="hlt">model</span> does fully account for allof the observed tidal power, tests indicate that the <span class="hlt">model</span> may not have completely converged. So better <span class="hlt">models</span> of the effects of ocean tides on polar <span class="hlt">motion</span> are still needed, both dynamical and empirical.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70014700','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70014700"><span>Analytical approach to calculation of response spectra from seismological <span class="hlt">models</span> of ground <span class="hlt">motion</span></span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Safak, Erdal</p> <p>1988-01-01</p> <p>An analytical approach to calculate response spectra from seismological <span class="hlt">models</span> of ground <span class="hlt">motion</span> is presented. Seismological <span class="hlt">models</span> have three major advantages over empirical <span class="hlt">models</span>: (1) they help in an understanding of the physics of earthquake mechanisms, (2) they can be used to predict ground <span class="hlt">motions</span> for future earthquakes and (3) they can be extrapolated to cases where there are no data available. As shown with this study, these <span class="hlt">models</span> also present a convenient form for the calculation of response spectra, by using the methods of random vibration theory, for a given magnitude and site conditions. The first part of the paper reviews the past <span class="hlt">models</span> for ground <span class="hlt">motion</span> description, and introduces the available seismological <span class="hlt">models</span>. Then, the random vibration equations for the spectral response are presented. The nonstationarity, spectral bandwidth and the correlation of the peaks are considered in the calculation of the peak response.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20110020642&hterms=Tidal+power&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3DTidal%2Bpower','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20110020642&hterms=Tidal+power&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3DTidal%2Bpower"><span>Observing and <span class="hlt">Modeling</span> Long-Period Tidal Variations in Polar <span class="hlt">Motion</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Gross, Richard S.; Dickman, S. R.</p> <p>2011-01-01</p> <p>By exchanging angular momentum with the solid Earth, ocean tides cause the Earth's rotation to change. While hydrodynamic tide <span class="hlt">models</span> have been used to study the effect of ocean tides on polar <span class="hlt">motion</span>, it is shown here that none of the published <span class="hlt">models</span> can fully account for the observed variations. An empirical ocean tide <span class="hlt">model</span> is therefore determined by fitting periodic terms at the tidal frequencies to polar <span class="hlt">motion</span> excitation observations, from which atmospheric and non-tidal oceanic effects were removed. While the empirical ocean tide <span class="hlt">model</span> does fully account for allof the observed tidal power, tests indicate that the <span class="hlt">model</span> may not have completely converged. So better <span class="hlt">models</span> of the effects of ocean tides on polar <span class="hlt">motion</span> are still needed, both dynamical and empirical.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015SPIE.9521E..07L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015SPIE.9521E..07L"><span>Human <span class="hlt">motion</span> recognition based on features and <span class="hlt">models</span> selected HMM</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lu, Haixiang; Zhou, Hongjun</p> <p>2015-03-01</p> <p>This paper research on the <span class="hlt">motion</span> recognition based on HMM with Kinect. Kinect provides skeletal data consist of 3D body joints with its lower price and convenience. In this work, several methods are used to determine the optimal subset of features among Cartesian coordinates, distance to hip center, velocity, angle and angular velocity, in order to improve the recognition rate. K-means is used for vector quantization and HMM is used as recognition method. HMM is an effective signal processing method which contains time calibration, provides a learning mechanism and recognition ability. Cluster numbers of K-means, structure and state numbers of HMM are optimized as well. The proposed methods are applied to the MSR Action3D dataset. Results show that the proposed methods obtain better recognition accuracy than the state of the art methods.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFM.S43B2788G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFM.S43B2788G"><span>Hybrid broadband Ground <span class="hlt">Motion</span> simulation based on a dynamic rupture <span class="hlt">model</span> of the 2011 Mw 9.0 Tohoku earthquake.</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Galvez, P.; Somerville, P.; Bayless, J.; Dalguer, L. A.</p> <p>2015-12-01</p> <p>The rupture process of the 2011 Tohoku earthquake exhibits depth-dependent variations in the frequency content of seismic radiation from the plate interface. This depth-varying rupture property has also been observed in other subduction zones (Lay et al, 2012). During the Tohoku earthquake, the shallow region radiated coherent low frequency seismic waves whereas the deeper region radiated high frequency waves. Several kinematic inversions (Suzuki et al, 2011; Lee et al, 2011; Bletery et al, 2014; Minson et al, 2014) detected seismic waves below 0.1 Hz coming from the shallow depths that produced slip larger than 40-50 meters close to the trench. Using empirical green functions, Asano & Iwata (2012), Kurahashi and Irikura (2011) and others detected regions of strong ground <span class="hlt">motion</span> radiation at frequencies up to 10Hz located mainly at the bottom of the plate interface. A recent dynamic <span class="hlt">model</span> that embodies this depth-dependent radiation using physical <span class="hlt">models</span> has been developed by Galvez et al (2014, 2015). In this <span class="hlt">model</span> the rupture process is <span class="hlt">modeled</span> using a linear weakening friction law with slip reactivation on the shallow region of the plate interface (Galvez et al, 2015). This <span class="hlt">model</span> reproduces the <span class="hlt">multiple</span> seismic wave fronts recorded on the Kik-net seismic network along the Japanese coast up to 0.1 Hz as well as the GPS displacements. In the deep region, the rupture sequence is consistent with the sequence of the strong ground <span class="hlt">motion</span> generation areas (SMGAs) that radiate high frequency ground <span class="hlt">motion</span> at the bottom of the plate interface (Kurahashi and Irikura, 2013). It remains challenging to perform ground <span class="hlt">motions</span> fully coupled with a dynamic rupture up to 10 Hz for a megathrust event. Therefore, to generate high frequency ground <span class="hlt">motions</span>, we make use of the stochastic approach of Graves and Pitarka (2010) but add to the source spectrum the slip rate function of the dynamic <span class="hlt">model</span>. In this hybrid-dynamic approach, the slip rate function is windowed with Gaussian</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/10587213','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/10587213"><span>A mathematical <span class="hlt">model</span> of <span class="hlt">motion</span> of the heart for use in generating source and attenuation maps for simulating emission imaging.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Pretorius, P H; King, M A; Tsui, B M; LaCroix, K J; Xia, W</p> <p>1999-11-01</p> <p>This manuscript documents the alteration of the heart <span class="hlt">model</span> of the three-dimensional (3D) mathematical cardiac torso (MCAT) phantom to represent cardiac <span class="hlt">motion</span>. The objective of the inclusion of <span class="hlt">motion</span> was to develop a digital simulation of the heart such that the impact of cardiac <span class="hlt">motion</span> on single-photon emission computed tomography (SPECT) imaging could be assessed and methods of quantitating cardiac function could be investigated. The <span class="hlt">motion</span> of the gated 3D MCAT's (gMCAT) heart is <span class="hlt">modeled</span> using 128 separate and evenly spaced time samples from a blood volume curve approximating an average heart cycle. Sets of adjacent time samples can be grouped together to represent a single time interval within the heart cycle. Maximum and minimum chamber volumes were selected to be similar to those of a normal healthy person while the total heart volume stayed constant during the cardiac cycle. Myocardial mass was conserved during the cardiac cycle and the bases of the ventricles were <span class="hlt">modeled</span> as moving towards the static apex. The orientation of the 3D MCAT heart was changed during contraction to rotate back and forth around the long axis through the center of the left ventricle (LV) using the end systolic time interval as the time point at which to reverse direction. Simple respiratory <span class="hlt">motion</span> was also introduced by changing the orientation of the long axis of the heart to represent its variation with respiration. Heart <span class="hlt">models</span> for 24 such orientations spanning the range of <span class="hlt">motion</span> during the respiratory cycle were averaged together for each time sample to represent the blurring of the heart during the acquisition of <span class="hlt">multiple</span> cardiac cycles. Finally, an option to <span class="hlt">model</span> apical thinning of the myocardium was included. As an illustration of the application of the gMCAT phantom, the gated heart <span class="hlt">model</span> was evaluated by measuring myocardial wall thickening. A linear relationship was obtained between maximum myocardial counts and myocardial thickness, similar to published results</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=behavioral+AND+science&pg=4&id=EJ985874','ERIC'); return false;" href="http://eric.ed.gov/?q=behavioral+AND+science&pg=4&id=EJ985874"><span>Alternative <span class="hlt">Multiple</span> Imputation Inference for Mean and Covariance Structure <span class="hlt">Modeling</span></span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Lee, Taehun; Cai, Li</p> <p>2012-01-01</p> <p><span class="hlt">Model</span>-based <span class="hlt">multiple</span> imputation has become an indispensable method in the educational and behavioral sciences. Mean and covariance structure <span class="hlt">models</span> are often fitted to multiply imputed data sets. However, the presence of <span class="hlt">multiple</span> random imputations complicates <span class="hlt">model</span> fit testing, which is an important aspect of mean and covariance structure…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://eric.ed.gov/?q=multiply&pg=4&id=EJ985874','ERIC'); return false;" href="https://eric.ed.gov/?q=multiply&pg=4&id=EJ985874"><span>Alternative <span class="hlt">Multiple</span> Imputation Inference for Mean and Covariance Structure <span class="hlt">Modeling</span></span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Lee, Taehun; Cai, Li</p> <p>2012-01-01</p> <p><span class="hlt">Model</span>-based <span class="hlt">multiple</span> imputation has become an indispensable method in the educational and behavioral sciences. Mean and covariance structure <span class="hlt">models</span> are often fitted to multiply imputed data sets. However, the presence of <span class="hlt">multiple</span> random imputations complicates <span class="hlt">model</span> fit testing, which is an important aspect of mean and covariance structure…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011PMB....56.1775H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011PMB....56.1775H"><span>Real-time prediction of respiratory <span class="hlt">motion</span> based on a local dynamic <span class="hlt">model</span> in an augmented space</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hong, S.-M.; Jung, B.-H.; Ruan, D.</p> <p>2011-03-01</p> <p><span class="hlt">Motion</span>-adaptive radiotherapy aims to deliver ablative radiation dose to the tumor target with minimal normal tissue exposure, by accounting for real-time target movement. In practice, prediction is usually necessary to compensate for system latency induced by measurement, communication and control. This work focuses on predicting respiratory <span class="hlt">motion</span>, which is most dominant for thoracic and abdominal tumors. We develop and investigate the use of a local dynamic <span class="hlt">model</span> in an augmented space, motivated by the observation that respiratory movement exhibits a locally circular pattern in a plane augmented with a delayed axis. By including the angular velocity as part of the system state, the proposed dynamic <span class="hlt">model</span> effectively captures the natural evolution of respiratory <span class="hlt">motion</span>. The first-order extended Kalman filter is used to propagate and update the state estimate. The target location is predicted by evaluating the local dynamic <span class="hlt">model</span> equations at the required prediction length. This method is complementary to existing work in that (1) the local circular <span class="hlt">motion</span> <span class="hlt">model</span> characterizes 'turning', overcoming the limitation of linear <span class="hlt">motion</span> <span class="hlt">models</span>; (2) it uses a natural state representation including the local angular velocity and updates the state estimate systematically, offering explicit physical interpretations; (3) it relies on a parametric <span class="hlt">model</span> and is much less data-satiate than the typical adaptive semiparametric or nonparametric method. We tested the performance of the proposed method with ten RPM traces, using the normalized root mean squared difference between the predicted value and the retrospective observation as the error metric. Its performance was compared with predictors based on the linear <span class="hlt">model</span>, the interacting <span class="hlt">multiple</span> linear <span class="hlt">models</span> and the kernel density estimator for various combinations of prediction lengths and observation rates. The local dynamic <span class="hlt">model</span> based approach provides the best performance for short to medium prediction lengths under relatively</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4432909','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4432909"><span>3D fluoroscopic image estimation using patient-specific 4DCBCT-based <span class="hlt">motion</span> <span class="hlt">models</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Dhou, Salam; Hurwitz, Martina; Mishra, Pankaj; Cai, Weixing; Rottmann, Joerg; Li, Ruijiang; Williams, Christopher; Wagar, Matthew; Berbeco, Ross; Ionascu, Dan; Lewis, John H.</p> <p>2015-01-01</p> <p>3D fluoroscopic images represent volumetric patient anatomy during treatment with high spatial and temporal resolution. 3D fluoroscopic images estimated using <span class="hlt">motion</span> <span class="hlt">models</span> built using 4DCT images, taken days or weeks prior to treatment, do not reliably represent patient anatomy during treatment. In this study we develop and perform initial evaluation of techniques to develop patient-specific <span class="hlt">motion</span> <span class="hlt">models</span> from 4D cone-beam CT (4DCBCT) images, taken immediately before treatment, and use these <span class="hlt">models</span> to estimate 3D fluoroscopic images based on 2D kV projections captured during treatment. We evaluate the accuracy of 3D fluoroscopic images by comparing to ground truth digital and physical phantom images. The performance of 4DCBCT- and 4DCT- based <span class="hlt">motion</span> <span class="hlt">models</span> are compared in simulated clinical situations representing tumor baseline shift or initial patient positioning errors. The results of this study demonstrate the ability for 4DCBCT imaging to generate <span class="hlt">motion</span> <span class="hlt">models</span> that can account for changes that cannot be accounted for with 4DCT-based <span class="hlt">motion</span> <span class="hlt">models</span>. When simulating tumor baseline shift and patient positioning errors of up to 5 mm, the average tumor localization error and the 95th percentile error in six datasets were 1.20 and 2.2 mm, respectively, for 4DCBCT-based <span class="hlt">motion</span> <span class="hlt">models</span>. 4DCT-based <span class="hlt">motion</span> <span class="hlt">models</span> applied to the same six datasets resulted in average tumor localization error and the 95th percentile error of 4.18 and 5.4 mm, respectively. Analysis of voxel-wise intensity differences was also conducted for all experiments. In summary, this study demonstrates the feasibility of 4DCBCT-based 3D fluoroscopic image generation in digital and physical phantoms, and shows the potential advantage of 4DCBCT-based 3D fluoroscopic image estimation when there are changes in anatomy between the time of 4DCT imaging and the time of treatment delivery. PMID:25905722</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25905722','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25905722"><span>3D fluoroscopic image estimation using patient-specific 4DCBCT-based <span class="hlt">motion</span> <span class="hlt">models</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Dhou, S; Hurwitz, M; Mishra, P; Cai, W; Rottmann, J; Li, R; Williams, C; Wagar, M; Berbeco, R; Ionascu, D; Lewis, J H</p> <p>2015-05-07</p> <p>3D fluoroscopic images represent volumetric patient anatomy during treatment with high spatial and temporal resolution. 3D fluoroscopic images estimated using <span class="hlt">motion</span> <span class="hlt">models</span> built using 4DCT images, taken days or weeks prior to treatment, do not reliably represent patient anatomy during treatment. In this study we developed and performed initial evaluation of techniques to develop patient-specific <span class="hlt">motion</span> <span class="hlt">models</span> from 4D cone-beam CT (4DCBCT) images, taken immediately before treatment, and used these <span class="hlt">models</span> to estimate 3D fluoroscopic images based on 2D kV projections captured during treatment. We evaluate the accuracy of 3D fluoroscopic images by comparison to ground truth digital and physical phantom images. The performance of 4DCBCT-based and 4DCT-based <span class="hlt">motion</span> <span class="hlt">models</span> are compared in simulated clinical situations representing tumor baseline shift or initial patient positioning errors. The results of this study demonstrate the ability for 4DCBCT imaging to generate <span class="hlt">motion</span> <span class="hlt">models</span> that can account for changes that cannot be accounted for with 4DCT-based <span class="hlt">motion</span> <span class="hlt">models</span>. When simulating tumor baseline shift and patient positioning errors of up to 5 mm, the average tumor localization error and the 95th percentile error in six datasets were 1.20 and 2.2 mm, respectively, for 4DCBCT-based <span class="hlt">motion</span> <span class="hlt">models</span>. 4DCT-based <span class="hlt">motion</span> <span class="hlt">models</span> applied to the same six datasets resulted in average tumor localization error and the 95th percentile error of 4.18 and 5.4 mm, respectively. Analysis of voxel-wise intensity differences was also conducted for all experiments. In summary, this study demonstrates the feasibility of 4DCBCT-based 3D fluoroscopic image generation in digital and physical phantoms and shows the potential advantage of 4DCBCT-based 3D fluoroscopic image estimation when there are changes in anatomy between the time of 4DCT imaging and the time of treatment delivery.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015PMB....60.3807D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015PMB....60.3807D"><span>3D fluoroscopic image estimation using patient-specific 4DCBCT-based <span class="hlt">motion</span> <span class="hlt">models</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Dhou, S.; Hurwitz, M.; Mishra, P.; Cai, W.; Rottmann, J.; Li, R.; Williams, C.; Wagar, M.; Berbeco, R.; Ionascu, D.; Lewis, J. H.</p> <p>2015-05-01</p> <p>3D fluoroscopic images represent volumetric patient anatomy during treatment with high spatial and temporal resolution. 3D fluoroscopic images estimated using <span class="hlt">motion</span> <span class="hlt">models</span> built using 4DCT images, taken days or weeks prior to treatment, do not reliably represent patient anatomy during treatment. In this study we developed and performed initial evaluation of techniques to develop patient-specific <span class="hlt">motion</span> <span class="hlt">models</span> from 4D cone-beam CT (4DCBCT) images, taken immediately before treatment, and used these <span class="hlt">models</span> to estimate 3D fluoroscopic images based on 2D kV projections captured during treatment. We evaluate the accuracy of 3D fluoroscopic images by comparison to ground truth digital and physical phantom images. The performance of 4DCBCT-based and 4DCT-based <span class="hlt">motion</span> <span class="hlt">models</span> are compared in simulated clinical situations representing tumor baseline shift or initial patient positioning errors. The results of this study demonstrate the ability for 4DCBCT imaging to generate <span class="hlt">motion</span> <span class="hlt">models</span> that can account for changes that cannot be accounted for with 4DCT-based <span class="hlt">motion</span> <span class="hlt">models</span>. When simulating tumor baseline shift and patient positioning errors of up to 5 mm, the average tumor localization error and the 95th percentile error in six datasets were 1.20 and 2.2 mm, respectively, for 4DCBCT-based <span class="hlt">motion</span> <span class="hlt">models</span>. 4DCT-based <span class="hlt">motion</span> <span class="hlt">models</span> applied to the same six datasets resulted in average tumor localization error and the 95th percentile error of 4.18 and 5.4 mm, respectively. Analysis of voxel-wise intensity differences was also conducted for all experiments. In summary, this study demonstrates the feasibility of 4DCBCT-based 3D fluoroscopic image generation in digital and physical phantoms and shows the potential advantage of 4DCBCT-based 3D fluoroscopic image estimation when there are changes in anatomy between the time of 4DCT imaging and the time of treatment delivery.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24469959','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24469959"><span>One-degree-of-freedom spherical <span class="hlt">model</span> for the passive <span class="hlt">motion</span> of the human ankle joint.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Sancisi, Nicola; Baldisserri, Benedetta; Parenti-Castelli, Vincenzo; Belvedere, Claudio; Leardini, Alberto</p> <p>2014-04-01</p> <p>Mathematical <span class="hlt">modelling</span> of mobility at the human ankle joint is essential for prosthetics and orthotic design. The scope of this study is to show that the ankle joint passive <span class="hlt">motion</span> can be represented by a one-degree-of-freedom spherical <span class="hlt">motion</span>. Moreover, this <span class="hlt">motion</span> is <span class="hlt">modelled</span> by a one-degree-of-freedom spherical parallel mechanism <span class="hlt">model</span>, and the optimal pivot-point position is determined. Passive <span class="hlt">motion</span> and anatomical data were taken from in vitro experiments in nine lower limb specimens. For each of these, a spherical mechanism, including the tibiofibular and talocalcaneal segments connected by a spherical pair and by the calcaneofibular and tibiocalcaneal ligament links, was defined from the corresponding experimental kinematics and geometry. An iterative procedure was used to optimize the geometry of the <span class="hlt">model</span>, able to predict original experimental <span class="hlt">motion</span>. The results of the simulations showed a good replication of the original natural <span class="hlt">motion</span>, despite the numerous <span class="hlt">model</span> assumptions and simplifications, with mean differences between experiments and predictions smaller than 1.3 mm (average 0.33 mm) for the three joint position components and smaller than 0.7° (average 0.32°) for the two out-of-sagittal plane rotations, once plotted versus the full flexion arc. The relevant pivot-point position after <span class="hlt">model</span> optimization was found within the tibial mortise, but not exactly in a central location. The present combined experimental and <span class="hlt">modelling</span> analysis of passive <span class="hlt">motion</span> at the human ankle joint shows that a one degree-of-freedom spherical mechanism predicts well what is observed in real joints, although its computational complexity is comparable to the standard hinge joint <span class="hlt">model</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFM.S43A2766K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFM.S43A2766K"><span>Regional Kappa <span class="hlt">Models</span> on North Anatolian Fault Zone (Turkey) and Their Use in Ground <span class="hlt">Motion</span> Simulations</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>karimzadeh Naghshineh, S.; Askan, A.; Sisman, F. N. N.</p> <p>2015-12-01</p> <p>One approach to <span class="hlt">model</span> the high-frequency attenuation of spectral amplitudes of S-waves is to express the observed exponential decay in terms of Kappa factor. Kappa is a significant parameter used for identifying the high frequency attenuation behavior of ground <span class="hlt">motions</span> as well as one of the key parameters for stochastic strong ground <span class="hlt">motion</span> simulation method. Recently, it has been also used in adjusting ground <span class="hlt">motion</span> predictions from one region to another. Currently, other than a previous study by the authors, there are no detailed studies on kappa using Turkish strong ground <span class="hlt">motion</span> datasets. In this study, with the objective of deriving regional kappa <span class="hlt">models</span>, we examine ground <span class="hlt">motion</span> datasets from different regions in Turkey with varying source properties, site classes and epicentral distances. Statistical tools are used to investigate the dependency of kappa on these parameters. In addition, potential correlations between kappa and Vs30 values of the stations are also studied. Main findings of this study are regional kappa <span class="hlt">models</span> on North Anatolian Fault zone. Finally, we also present high-frequency strong <span class="hlt">motion</span> simulations of past events in the selected regions using the proposed kappa <span class="hlt">models</span>. Regardless of the magnitude, source-to-site distance and local site conditions at the stations, the high-frequency spectral decay is simulated effectively.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012PMB....57.5787H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012PMB....57.5787H"><span>Couch-based <span class="hlt">motion</span> compensation: <span class="hlt">modelling</span>, simulation and real-time experiments</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Haas, Olivier C. L.; Skworcow, Piotr; Paluszczyszyn, Daniel; Sahih, Abdelhamid; Ruta, Mariusz; Mills, John A.</p> <p>2012-09-01</p> <p>The paper presents a couch-based active <span class="hlt">motion</span> compensation strategy evaluated in simulation and validated experimentally using both a research and a clinical Elekta Precise Table™. The control strategy combines a Kalman filter to predict the surrogate <span class="hlt">motion</span> used as a reference by a linear <span class="hlt">model</span> predictive controller with the control action calculation based on estimated position and velocity feedback provided by an observer as well as predicted couch position and velocity using a linearized state space <span class="hlt">model</span>. An inversion technique is used to compensate for the dead-zone nonlinearity. New generic couch <span class="hlt">models</span> are presented and applied to <span class="hlt">model</span> the Elekta Precise Table™ dynamics and nonlinearities including dead zone. Couch deflection was measured for different manufacturers and found to be up to 25 mm. A feed-forward approach is proposed to compensate for such couch deflection. Simultaneous <span class="hlt">motion</span> compensation for longitudinal, lateral and vertical <span class="hlt">motions</span> was evaluated using arbitrary trajectories generated from sensors or loaded from files. Tracking errors were between 0.5 and 2 mm RMS. A dosimetric evaluation of the <span class="hlt">motion</span> compensation was done using a sinusoidal waveform. No notable differences were observed between films obtained for a fixed- or <span class="hlt">motion</span>-compensated target. Further dosimetric improvement could be made by combining gating, based on tracking error together with beam on/off time, and PSS compensation.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li class="active"><span>21</span></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_21 --> <div id="page_22" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li class="active"><span>22</span></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="421"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/22951301','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/22951301"><span>Couch-based <span class="hlt">motion</span> compensation: <span class="hlt">modelling</span>, simulation and real-time experiments.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Haas, Olivier C L; Skworcow, Piotr; Paluszczyszyn, Daniel; Sahih, Abdelhamid; Ruta, Mariusz; Mills, John A</p> <p>2012-09-21</p> <p>The paper presents a couch-based active <span class="hlt">motion</span> compensation strategy evaluated in simulation and validated experimentally using both a research and a clinical Elekta Precise Table™. The control strategy combines a Kalman filter to predict the surrogate <span class="hlt">motion</span> used as a reference by a linear <span class="hlt">model</span> predictive controller with the control action calculation based on estimated position and velocity feedback provided by an observer as well as predicted couch position and velocity using a linearized state space <span class="hlt">model</span>. An inversion technique is used to compensate for the dead-zone nonlinearity. New generic couch <span class="hlt">models</span> are presented and applied to <span class="hlt">model</span> the Elekta Precise Table™ dynamics and nonlinearities including dead zone. Couch deflection was measured for different manufacturers and found to be up to 25 mm. A feed-forward approach is proposed to compensate for such couch deflection. Simultaneous <span class="hlt">motion</span> compensation for longitudinal, lateral and vertical <span class="hlt">motions</span> was evaluated using arbitrary trajectories generated from sensors or loaded from files. Tracking errors were between 0.5 and 2 mm RMS. A dosimetric evaluation of the <span class="hlt">motion</span> compensation was done using a sinusoidal waveform. No notable differences were observed between films obtained for a fixed- or <span class="hlt">motion</span>-compensated target. Further dosimetric improvement could be made by combining gating, based on tracking error together with beam on/off time, and PSS compensation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010OptEn..49f7003C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010OptEn..49f7003C"><span>Specification of hierarchical-<span class="hlt">model</span>-based fast quarter-pixel <span class="hlt">motion</span> estimation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Cho, Junsang; Suh, Jung W.; Jeon, Gwanggil; Jeong, Jechang</p> <p>2010-06-01</p> <p>We propose a robust and fast quarter-pixel <span class="hlt">motion</span> estimation algorithm. This algorithm is an advanced version of the previously proposed <span class="hlt">model</span>-based quarter-pixel <span class="hlt">motion</span> estimation (MBQME). MBQME has many advantages in computational complexity, running speed, and hardware implementations. But it has the problem that it does not find the quarter-pixel positions that locate beyond the half-pixel positions. That is one of limitations of <span class="hlt">model</span>-based <span class="hlt">motion</span> estimation methods, and it leads to both peak-SNR degradation and bit-rate increase. To solve this problem, we propose a hierarchical mathematical <span class="hlt">model</span> with minimum interpolations. Through this <span class="hlt">model</span>, we can determine a <span class="hlt">motion</span> vector at every quarter-pixel point, which is perfectly compatible with the quarter-pixel <span class="hlt">motion</span> estimation method within international video coding standards such as MPEG-4 and H.264/AVC. The simulation results show that the proposed method yields almost the same or even better peak-SNR performance than that of full-search quarter-pixel <span class="hlt">motion</span> estimation, with much lower computational complexity.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/22168707','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/22168707"><span>Nuclear quadrupole resonance lineshape analysis for different <span class="hlt">motional</span> <span class="hlt">models</span>: stochastic Liouville approach.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Kruk, D; Earle, K A; Mielczarek, A; Kubica, A; Milewska, A; Moscicki, J</p> <p>2011-12-14</p> <p>A general theory of lineshapes in nuclear quadrupole resonance (NQR), based on the stochastic Liouville equation, is presented. The description is valid for arbitrary <span class="hlt">motional</span> conditions (particularly beyond the valid range of perturbation approaches) and interaction strengths. It can be applied to the computation of NQR spectra for any spin quantum number and for any applied magnetic field. The treatment presented here is an adaptation of the "Swedish slow <span class="hlt">motion</span> theory," [T. Nilsson and J. Kowalewski, J. Magn. Reson. 146, 345 (2000)] originally formulated for paramagnetic systems, to NQR spectral analysis. The description is formulated for simple (Brownian) diffusion, free diffusion, and jump diffusion <span class="hlt">models</span>. The two latter <span class="hlt">models</span> account for molecular cooperativity effects in dense systems (such as liquids of high viscosity or molecular glasses). The sensitivity of NQR slow <span class="hlt">motion</span> spectra to the mechanism of the <span class="hlt">motional</span> processes modulating the nuclear quadrupole interaction is discussed. © 2011 American Institute of Physics</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015OptEn..54f3104L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015OptEn..54f3104L"><span>Kinematic <span class="hlt">model</span> for the space-variant image <span class="hlt">motion</span> of star sensors under dynamical conditions</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Liu, Chao-Shan; Hu, Lai-Hong; Liu, Guang-Bin; Yang, Bo; Li, Ai-Jun</p> <p>2015-06-01</p> <p>A kinematic description of a star spot in the focal plane is presented for star sensors under dynamical conditions, which involves all necessary parameters such as the image <span class="hlt">motion</span>, velocity, and attitude parameters of the vehicle. Stars at different locations of the focal plane correspond to the slightly different orientation and extent of <span class="hlt">motion</span> blur, which characterize the space-variant point spread function. Finally, the image <span class="hlt">motion</span>, the energy distribution, and centroid extraction are numerically investigated using the kinematic <span class="hlt">model</span> under dynamic conditions. A centroid error of eight successive iterations <0.002 pixel is used as the termination criterion for the Richardson-Lucy deconvolution algorithm. The kinematic <span class="hlt">model</span> of a star sensor is useful for evaluating the compensation algorithms of <span class="hlt">motion</span>-blurred images.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://eric.ed.gov/?q=plot&pg=6&id=EJ1040041','ERIC'); return false;" href="https://eric.ed.gov/?q=plot&pg=6&id=EJ1040041"><span>Applying <span class="hlt">Model</span> Analysis to a Resource-Based Analysis of the Force and <span class="hlt">Motion</span> Conceptual Evaluation</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Smith, Trevor I.; Wittmann, Michael C.; Carter, Tom</p> <p>2014-01-01</p> <p>Previously, we analyzed the Force and <span class="hlt">Motion</span> Conceptual Evaluation in terms of a resources-based <span class="hlt">model</span> that allows for clustering of questions so as to provide useful information on how students correctly or incorrectly reason about physics. In this paper, we apply <span class="hlt">model</span> analysis to show that the associated <span class="hlt">model</span> plots provide more information…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=plot&pg=5&id=EJ1040041','ERIC'); return false;" href="http://eric.ed.gov/?q=plot&pg=5&id=EJ1040041"><span>Applying <span class="hlt">Model</span> Analysis to a Resource-Based Analysis of the Force and <span class="hlt">Motion</span> Conceptual Evaluation</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Smith, Trevor I.; Wittmann, Michael C.; Carter, Tom</p> <p>2014-01-01</p> <p>Previously, we analyzed the Force and <span class="hlt">Motion</span> Conceptual Evaluation in terms of a resources-based <span class="hlt">model</span> that allows for clustering of questions so as to provide useful information on how students correctly or incorrectly reason about physics. In this paper, we apply <span class="hlt">model</span> analysis to show that the associated <span class="hlt">model</span> plots provide more information…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70033688','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70033688"><span>Key elements of regional seismic velocity <span class="hlt">models</span> for long period ground <span class="hlt">motion</span> simulations</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Brocher, T.M.</p> <p>2008-01-01</p> <p>Regional 3-D seismic velocity <span class="hlt">models</span> used for broadband strong <span class="hlt">motion</span> simulations must include compressional-wave velocity (Vp), shear-wave velocity (Vs), intrinsic attenuation (Qp, Qs), and density. Vs and Qs are the most important of these parameters because the strongest ground <span class="hlt">motions</span> are generated chiefly by shear- and surface-wave arrivals. Because Vp data are more common than Vs data, many researchers first develop a Vp <span class="hlt">model</span> and convert it to a Vs <span class="hlt">model</span>. I describe recent empirical relations between Vs, Vp, Qs, Qp, and density that allow velocity <span class="hlt">models</span> to be rapidly and accurately calculated. ?? Springer Science+Business Media B.V. 2007.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19880025726&hterms=models+logistic&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dmodels%2Blogistic','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19880025726&hterms=models+logistic&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dmodels%2Blogistic"><span>The use of the logistic <span class="hlt">model</span> in space <span class="hlt">motion</span> sickness prediction</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Lin, Karl K.; Reschke, Millard F.</p> <p>1987-01-01</p> <p>The one-equation and the two-equation logistic <span class="hlt">models</span> were used to predict subjects' susceptibility to <span class="hlt">motion</span> sickness in KC-135 parabolic flights using data from other ground-based <span class="hlt">motion</span> sickness tests. The results show that the logistic <span class="hlt">models</span> correctly predicted substantially more cases (an average of 13 percent) in the data subset used for <span class="hlt">model</span> building. Overall, the logistic <span class="hlt">models</span> ranged from 53 to 65 percent predictions of the three endpoint parameters, whereas the Bayes linear discriminant procedure ranged from 48 to 65 percent correct for the cross validation sample.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19880025726&hterms=model-building&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dmodel-building','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19880025726&hterms=model-building&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dmodel-building"><span>The use of the logistic <span class="hlt">model</span> in space <span class="hlt">motion</span> sickness prediction</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Lin, Karl K.; Reschke, Millard F.</p> <p>1987-01-01</p> <p>The one-equation and the two-equation logistic <span class="hlt">models</span> were used to predict subjects' susceptibility to <span class="hlt">motion</span> sickness in KC-135 parabolic flights using data from other ground-based <span class="hlt">motion</span> sickness tests. The results show that the logistic <span class="hlt">models</span> correctly predicted substantially more cases (an average of 13 percent) in the data subset used for <span class="hlt">model</span> building. Overall, the logistic <span class="hlt">models</span> ranged from 53 to 65 percent predictions of the three endpoint parameters, whereas the Bayes linear discriminant procedure ranged from 48 to 65 percent correct for the cross validation sample.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFM.V14A..06M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFM.V14A..06M"><span>How Plates Pull Transforms Apart: 3-D Numerical <span class="hlt">Models</span> of Oceanic Transform Fault Response to Changes in Plate <span class="hlt">Motion</span> Direction</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Morrow, T. A.; Mittelstaedt, E. L.; Olive, J. A. L.</p> <p>2015-12-01</p> <p>Observations along oceanic fracture zones suggest that some mid-ocean ridge transform faults (TFs) previously split into <span class="hlt">multiple</span> strike-slip segments separated by short (<~50 km) intra-transform spreading centers and then reunited to a single TF trace. This history of segmentation appears to correspond with changes in plate <span class="hlt">motion</span> direction. Despite the clear evidence of TF segmentation, the processes governing its development and evolution are not well characterized. Here we use a 3-D, finite-difference / marker-in-cell technique to <span class="hlt">model</span> the evolution of localized strain at a TF subjected to a sudden change in plate <span class="hlt">motion</span> direction. We simulate the oceanic lithosphere and underlying asthenosphere at a ridge-transform-ridge setting using a visco-elastic-plastic rheology with a history-dependent plastic weakening law and a temperature- and stress-dependent mantle viscosity. To simulate the development of topography, a low density, low viscosity 'sticky air' layer is present above the oceanic lithosphere. The initial thermal gradient follows a half-space cooling solution with an offset across the TF. We impose an enhanced thermal diffusivity in the uppermost 6 km of lithosphere to simulate the effects of hydrothermal circulation. An initial weak seed in the lithosphere helps localize shear deformation between the two offset ridge axes to form a TF. For each <span class="hlt">model</span> case, the simulation is run initially with TF-parallel plate <span class="hlt">motion</span> until the thermal structure reaches a steady state. The direction of plate <span class="hlt">motion</span> is then rotated either instantaneously or over a specified time period, placing the TF in a state of trans-tension. <span class="hlt">Model</span> runs continue until the system reaches a new steady state. Parameters varied here include: initial TF length, spreading rate, and the rotation rate and magnitude of spreading obliquity. We compare our <span class="hlt">model</span> predictions to structural observations at existing TFs and records of TF segmentation preserved in oceanic fracture zones.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/5105325','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/5105325"><span>Plate <span class="hlt">motion</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Gordon, R.G. )</p> <p>1991-01-01</p> <p>The <span class="hlt">motion</span> of tectonic plates on the earth is characterized in a critical review of U.S. research from the period 1987-1990. Topics addressed include the NUVEL-1 global <span class="hlt">model</span> of current plate <span class="hlt">motions</span>, diffuse plate boundaries and the oceanic lithosphere, the relation between plate <span class="hlt">motions</span> and distributed deformations, accelerations and the steadiness of plate <span class="hlt">motions</span>, the distribution of current Pacific-North America <span class="hlt">motion</span> across western North America and its margin, plate reconstructions and their uncertainties, hotspots, and plate dynamics. A comprehensive bibliography is provided. 126 refs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/23075284','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/23075284"><span>Explaining clinical behaviors using <span class="hlt">multiple</span> theoretical <span class="hlt">models</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Eccles, Martin P; Grimshaw, Jeremy M; MacLennan, Graeme; Bonetti, Debbie; Glidewell, Liz; Pitts, Nigel B; Steen, Nick; Thomas, Ruth; Walker, Anne; Johnston, Marie</p> <p>2012-10-17</p> <p>, the mean construct scores were above the mid-point on the scale with median values across the five behaviors generally being above four out of seven and the range being from 1.53 to 6.01. Across all of the theories, the highest proportion of the variance explained was always for intention and the lowest was for behavior. The Knowledge-Attitudes-Behavior <span class="hlt">Model</span> performed poorly across all behaviors and dependent variables; CSSRM also performed poorly. For TPB, SCT, II, and LT across the five behaviors, we predicted median R2 of 25% to 42.6% for intention, 6.2% to 16% for behavioral simulation, and 2.4% to 6.3% for behavior. We operationalized <span class="hlt">multiple</span> theories measuring across five behaviors. Continuing challenges that emerge from our work are: better specification of behaviors, better operationalization of theories; how best to appropriately extend the range of theories; further assessment of the value of theories in different settings and groups; exploring the implications of these methods for the management of chronic diseases; and moving to experimental designs to allow an understanding of behavior change.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3500222','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3500222"><span>Explaining clinical behaviors using <span class="hlt">multiple</span> theoretical <span class="hlt">models</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p></p> <p>2012-01-01</p> <p>. For the predictor variables, the mean construct scores were above the mid-point on the scale with median values across the five behaviors generally being above four out of seven and the range being from 1.53 to 6.01. Across all of the theories, the highest proportion of the variance explained was always for intention and the lowest was for behavior. The Knowledge-Attitudes-Behavior <span class="hlt">Model</span> performed poorly across all behaviors and dependent variables; CSSRM also performed poorly. For TPB, SCT, II, and LT across the five behaviors, we predicted median R2 of 25% to 42.6% for intention, 6.2% to 16% for behavioral simulation, and 2.4% to 6.3% for behavior. Conclusions We operationalized <span class="hlt">multiple</span> theories measuring across five behaviors. Continuing challenges that emerge from our work are: better specification of behaviors, better operationalization of theories; how best to appropriately extend the range of theories; further assessment of the value of theories in different settings and groups; exploring the implications of these methods for the management of chronic diseases; and moving to experimental designs to allow an understanding of behavior change. PMID:23075284</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25109893','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25109893"><span>Cellular immunotherapy in <span class="hlt">multiple</span> myeloma: lessons from preclinical <span class="hlt">models</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Binsfeld, M; Fostier, K; Muller, J; Baron, F; Schots, R; Beguin, Y; Heusschen, R; Caers, J</p> <p>2014-12-01</p> <p>The majority of <span class="hlt">multiple</span> myeloma patients relapse with the current treatment strategies, raising the need for alternative therapeutic approaches. Cellular immunotherapy is a rapidly evolving field and currently being translated into clinical trials with encouraging results in several cancer types, including <span class="hlt">multiple</span> myeloma. Murine <span class="hlt">multiple</span> myeloma <span class="hlt">models</span> are of critical importance for the development and refinement of cellular immunotherapy. In this review, we summarize the immune cell changes that occur in <span class="hlt">multiple</span> myeloma patients and we discuss the cell-based immunotherapies that have been tested in <span class="hlt">multiple</span> myeloma, with a focus on murine <span class="hlt">models</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014JGRF..119.1833A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014JGRF..119.1833A"><span>A mechanistic <span class="hlt">model</span> linking insect (Hydropsychidae) silk nets to incipient sediment <span class="hlt">motion</span> in gravel-bedded streams</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Albertson, Lindsey K.; Sklar, Leonard S.; Pontau, Patricia; Dow, Michelle; Cardinale, Bradley J.</p> <p>2014-09-01</p> <p>Plants and animals affect stream morphodynamics across a range of scales, yet including biological traits of organisms in geomorphic process <span class="hlt">models</span> remains a fundamental challenge. For example, laboratory experiments have shown that silk nets built by caddisfly larvae (Trichoptera: Hydropsychidae) can increase the shear stress required to initiate bed <span class="hlt">motion</span> by more than a factor of 2. The contributions of specific biological traits are not well understood, however. Here we develop a theoretical <span class="hlt">model</span> for the effects of insect nets on the threshold of sediment <span class="hlt">motion</span>, τ*crit, that accounts for the mechanical properties, geometry, and vertical distribution of insect silk, as well as interactions between insect species. To parameterize the <span class="hlt">model</span>, we measure the tensile strength, diameter, and number of silk threads in nets built by two common species of caddisfly, Arctopsyche californica and Ceratopsyche oslari. We compare <span class="hlt">model</span> predictions with new measurements of τ*crit in experiments where we varied grain size and caddisfly species composition. The <span class="hlt">model</span> is consistent with experimental results for single species, which show that the increase in τ*crit above the abiotic control peaks at 40-70% for 10-22 mm sediments and declines with increasing grain size. For the polyculture experiments, however, the <span class="hlt">model</span> underpredicts the measured increase in τ*crit when two caddisfly species are present in sediments of larger grain sizes. Overall, the <span class="hlt">model</span> helps explain why the presence of caddisfly silk can substantially increase the forces needed to initiate sediment <span class="hlt">motion</span> in gravel-bedded streams and also illustrates the challenge of parameterizing the behavior of <span class="hlt">multiple</span> interacting species in a physical <span class="hlt">model</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012SPIE.8316E..1AG','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012SPIE.8316E..1AG"><span>Coronary arteries <span class="hlt">motion</span> <span class="hlt">modeling</span> on 2D x-ray images</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gao, Yang; Sundar, Hari</p> <p>2012-02-01</p> <p>During interventional procedures, 3D imaging modalities like CT and MRI are not commonly used due to interference with the surgery and radiation exposure concerns. Therefore, real-time information is usually limited and building <span class="hlt">models</span> of cardiac <span class="hlt">motion</span> are difficult. In such case, vessel <span class="hlt">motion</span> <span class="hlt">modeling</span> based on 2-D angiography images become indispensable. Due to issues with existing vessel segmentation algorithms and the lack of contrast in occluded vessels, manual segmentation of certain branches is usually necessary. In addition, such occluded branches are the most important vessels during coronary interventions and obtaining <span class="hlt">motion</span> <span class="hlt">models</span> for these can greatly help in reducing the procedure time and radiation exposure. Segmenting different cardiac phases independently does not guarantee temporal consistency and is not efficient for occluded branches required manual segmentation. In this paper, we propose a coronary <span class="hlt">motion</span> <span class="hlt">modeling</span> system which extracts the coronary tree for every cardiac phase, maintaining the segmentation by tracking the coronary tree during the cardiac cycle. It is able to map every frame to the specific cardiac phase, thereby inferring the shape information of the coronary arteries using the <span class="hlt">model</span> corresponding to its phase. Our experiments show that our <span class="hlt">motion</span> <span class="hlt">modeling</span> system can achieve promising results with real-time performance.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3140976','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3140976"><span>Combining Feature Selection and Integration—A Neural <span class="hlt">Model</span> for MT <span class="hlt">Motion</span> Selectivity</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Beck, Cornelia; Neumann, Heiko</p> <p>2011-01-01</p> <p>Background The computation of pattern <span class="hlt">motion</span> in visual area MT based on <span class="hlt">motion</span> input from area V1 has been investigated in many experiments and <span class="hlt">models</span> attempting to replicate the main mechanisms. Two different core conceptual approaches were developed to explain the findings. In integrationist <span class="hlt">models</span> the key mechanism to achieve pattern selectivity is the nonlinear integration of V1 <span class="hlt">motion</span> activity. In contrast, selectionist <span class="hlt">models</span> focus on the <span class="hlt">motion</span> computation at positions with 2D features. Methodology/Principal Findings Recent experiments revealed that neither of the two concepts alone is sufficient to explain all experimental data and that most of the existing <span class="hlt">models</span> cannot account for the complex behaviour found. MT pattern selectivity changes over time for stimuli like type II plaids from vector average to the direction computed with an intersection of constraint rule or by feature tracking. Also, the spatial arrangement of the stimulus within the receptive field of a MT cell plays a crucial role. We propose a recurrent neural <span class="hlt">model</span> showing how feature integration and selection can be combined into one common architecture to explain these findings. The key features of the <span class="hlt">model</span> are the computation of 1D and 2D <span class="hlt">motion</span> in <span class="hlt">model</span> area V1 subpopulations that are integrated in <span class="hlt">model</span> MT cells using feedforward and feedback processing. Our results are also in line with findings concerning the solution of the aperture problem. Conclusions/Significance We propose a new neural <span class="hlt">model</span> for MT pattern computation and <span class="hlt">motion</span> disambiguation that is based on a combination of feature selection and integration. The <span class="hlt">model</span> can explain a range of recent neurophysiological findings including temporally dynamic behaviour. PMID:21814543</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017sfcc.confE..43P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017sfcc.confE..43P"><span><span class="hlt">Multiplicity</span> and Small Clusters: Theory/<span class="hlt">Models</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Parker, Richard</p> <p>2017-06-01</p> <p>In this talk I will review the recent theory and simulations of binary star and low-mass cluster formation. I will discuss the various formation mechanisms proposed for binary and <span class="hlt">multiple</span> star formation, and compare recent simulations to the observed properties of binaries. I will describe efforts to distinguish high-order <span class="hlt">multiples</span> from low-mass star clusters and how their subsequent evolution may sculpt the binary properties observed in the Galactic field. Finally, I will discuss how the missing physics from current simulations may affect comparisons with observations, and highlight future prospects in this area.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4652597','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4652597"><span>Sensitivity of Tumor <span class="hlt">Motion</span> Simulation Accuracy to Lung Biomechanical <span class="hlt">Modeling</span> Approaches and Parameters</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Tehrani, Joubin Nasehi; Yang, Yin; Werner, Rene; Lu, Wei; Low, Daniel; Guo, Xiaohu</p> <p>2015-01-01</p> <p>Finite element analysis (FEA)-based biomechanical <span class="hlt">modeling</span> can be used to predict lung respiratory <span class="hlt">motion</span>. In this technique, elastic <span class="hlt">models</span> and biomechanical parameters are two important factors that determine <span class="hlt">modeling</span> accuracy. We systematically evaluated the effects of lung and lung tumor biomechanical <span class="hlt">modeling</span> approaches and related parameters to improve the accuracy of <span class="hlt">motion</span> simulation of lung tumor center of mass (TCM) displacements. Experiments were conducted with four-dimensional computed tomography (4D-CT). A Quasi-Newton FEA was performed to simulate lung and related tumor displacements between end-expiration (phase 50%) and other respiration phases (0%, 10%, 20%, 30%, and 40%). Both linear isotropic and non-linear hyperelastic materials, including the Neo-Hookean compressible and uncoupled Mooney-Rivlin <span class="hlt">models</span>, were used to create a finite element <span class="hlt">model</span> (FEM) of lung and tumors. Lung surface displacement vector fields (SDVFs) were obtained by registering the 50% phase CT to other respiration phases, using the non-rigid demons registration algorithm. The obtained SDVFs were used as lung surface displacement boundary conditions in FEM. The sensitivity of TCM displacement to lung and tumor biomechanical parameters was assessed in eight patients for all three <span class="hlt">models</span>. Patient-specific optimal parameters were estimated by minimizing the TCM <span class="hlt">motion</span> simulation errors between phase 50% and phase 0%. The uncoupled Mooney-Rivlin material <span class="hlt">model</span> showed the highest TCM <span class="hlt">motion</span> simulation accuracy. The average TCM <span class="hlt">motion</span> simulation absolute errors for the Mooney-Rivlin material <span class="hlt">model</span> along left-right (LR), anterior-posterior (AP), and superior-inferior (SI) directions were 0.80 mm, 0.86 mm, and 1.51 mm, respectively. The proposed strategy provides a reliable method to estimate patient-specific biomechanical parameters in FEM for lung tumor <span class="hlt">motion</span> simulation. PMID:26531324</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26531324','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26531324"><span>Sensitivity of tumor <span class="hlt">motion</span> simulation accuracy to lung biomechanical <span class="hlt">modeling</span> approaches and parameters.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Tehrani, Joubin Nasehi; Yang, Yin; Werner, Rene; Lu, Wei; Low, Daniel; Guo, Xiaohu; Wang, Jing</p> <p>2015-11-21</p> <p>Finite element analysis (FEA)-based biomechanical <span class="hlt">modeling</span> can be used to predict lung respiratory <span class="hlt">motion</span>. In this technique, elastic <span class="hlt">models</span> and biomechanical parameters are two important factors that determine <span class="hlt">modeling</span> accuracy. We systematically evaluated the effects of lung and lung tumor biomechanical <span class="hlt">modeling</span> approaches and related parameters to improve the accuracy of <span class="hlt">motion</span> simulation of lung tumor center of mass (TCM) displacements. Experiments were conducted with four-dimensional computed tomography (4D-CT). A Quasi-Newton FEA was performed to simulate lung and related tumor displacements between end-expiration (phase 50%) and other respiration phases (0%, 10%, 20%, 30%, and 40%). Both linear isotropic and non-linear hyperelastic materials, including the neo-Hookean compressible and uncoupled Mooney-Rivlin <span class="hlt">models</span>, were used to create a finite element <span class="hlt">model</span> (FEM) of lung and tumors. Lung surface displacement vector fields (SDVFs) were obtained by registering the 50% phase CT to other respiration phases, using the non-rigid demons registration algorithm. The obtained SDVFs were used as lung surface displacement boundary conditions in FEM. The sensitivity of TCM displacement to lung and tumor biomechanical parameters was assessed in eight patients for all three <span class="hlt">models</span>. Patient-specific optimal parameters were estimated by minimizing the TCM <span class="hlt">motion</span> simulation errors between phase 50% and phase 0%. The uncoupled Mooney-Rivlin material <span class="hlt">model</span> showed the highest TCM <span class="hlt">motion</span> simulation accuracy. The average TCM <span class="hlt">motion</span> simulation absolute errors for the Mooney-Rivlin material <span class="hlt">model</span> along left-right, anterior-posterior, and superior-inferior directions were 0.80 mm, 0.86 mm, and 1.51 mm, respectively. The proposed strategy provides a reliable method to estimate patient-specific biomechanical parameters in FEM for lung tumor <span class="hlt">motion</span> simulation.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li class="active"><span>22</span></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_22 --> <div id="page_23" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li class="active"><span>23</span></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="441"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015PMB....60.8833N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015PMB....60.8833N"><span>Sensitivity of tumor <span class="hlt">motion</span> simulation accuracy to lung biomechanical <span class="hlt">modeling</span> approaches and parameters</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Nasehi Tehrani, Joubin; Yang, Yin; Werner, Rene; Lu, Wei; Low, Daniel; Guo, Xiaohu; Wang, Jing</p> <p>2015-11-01</p> <p>Finite element analysis (FEA)-based biomechanical <span class="hlt">modeling</span> can be used to predict lung respiratory <span class="hlt">motion</span>. In this technique, elastic <span class="hlt">models</span> and biomechanical parameters are two important factors that determine <span class="hlt">modeling</span> accuracy. We systematically evaluated the effects of lung and lung tumor biomechanical <span class="hlt">modeling</span> approaches and related parameters to improve the accuracy of <span class="hlt">motion</span> simulation of lung tumor center of mass (TCM) displacements. Experiments were conducted with four-dimensional computed tomography (4D-CT). A Quasi-Newton FEA was performed to simulate lung and related tumor displacements between end-expiration (phase 50%) and other respiration phases (0%, 10%, 20%, 30%, and 40%). Both linear isotropic and non-linear hyperelastic materials, including the neo-Hookean compressible and uncoupled Mooney-Rivlin <span class="hlt">models</span>, were used to create a finite element <span class="hlt">model</span> (FEM) of lung and tumors. Lung surface displacement vector fields (SDVFs) were obtained by registering the 50% phase CT to other respiration phases, using the non-rigid demons registration algorithm. The obtained SDVFs were used as lung surface displacement boundary conditions in FEM. The sensitivity of TCM displacement to lung and tumor biomechanical parameters was assessed in eight patients for all three <span class="hlt">models</span>. Patient-specific optimal parameters were estimated by minimizing the TCM <span class="hlt">motion</span> simulation errors between phase 50% and phase 0%. The uncoupled Mooney-Rivlin material <span class="hlt">model</span> showed the highest TCM <span class="hlt">motion</span> simulation accuracy. The average TCM <span class="hlt">motion</span> simulation absolute errors for the Mooney-Rivlin material <span class="hlt">model</span> along left-right, anterior-posterior, and superior-inferior directions were 0.80 mm, 0.86 mm, and 1.51 mm, respectively. The proposed strategy provides a reliable method to estimate patient-specific biomechanical parameters in FEM for lung tumor <span class="hlt">motion</span> simulation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19890006218','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19890006218"><span>Toward a computational theory for <span class="hlt">motion</span> understanding: The expert animators <span class="hlt">model</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Mohamed, Ahmed S.; Armstrong, William W.</p> <p>1988-01-01</p> <p>Artificial intelligence researchers claim to understand some aspect of human intelligence when their <span class="hlt">model</span> is able to emulate it. In the context of computer graphics, the ability to go from <span class="hlt">motion</span> representation to convincing animation should accordingly be treated not simply as a trick for computer graphics programmers but as important epistemological and methodological goal. In this paper we investigate a unifying <span class="hlt">model</span> for animating a group of articulated bodies such as humans and robots in a three-dimensional environment. The proposed <span class="hlt">model</span> is considered in the framework of knowledge representation and processing, with special reference to <span class="hlt">motion</span> knowledge. The <span class="hlt">model</span> is meant to help setting the basis for a computational theory for <span class="hlt">motion</span> understanding applied to articulated bodies.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24896359','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24896359"><span>Simulation <span class="hlt">model</span> for combined <span class="hlt">motion</span> of myosin cross-bridges agrees with experimental data.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Marandos, Peter; Midde, Krishna</p> <p>2014-06-01</p> <p>The motivation for this work was to derive a theoretical <span class="hlt">model</span> for the combined <span class="hlt">motion</span> of a sample of muscle tissue with a small number (approximately 12) of myosin molecules. This was then compared to data collected at the University of North Texas Health Science center. A theoretical <span class="hlt">model</span> of the <span class="hlt">motion</span> of the myosin cross-bridges has been derived. The solution is a combination of solutions from the classical harmonic oscillator, Brownian <span class="hlt">motion</span>, and Maxwell-Boltzmann statistics. The <span class="hlt">model</span> illustrates the myosin behavior as a function of the number of myosin molecules, the temperature of the sample, and the spring constant. The results show that there is good agreement between the theoretical <span class="hlt">model</span> and experimental data.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013SPIE.8856E..1EE','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013SPIE.8856E..1EE"><span><span class="hlt">Motion</span> estimation and segmentation in CT cardiac images using the Hermite transform and active shape <span class="hlt">models</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Escalante-Ramírez, Boris; Moya-Albor, Ernesto; Barba-J, Leiner; Arambula Cosio, Fernando; Vallejo, Enrique</p> <p>2013-09-01</p> <p>Considering the importance of studying the movement of certain cardiac structures such as left ventricle and myocardial wall for better medical diagnosis, we propose a method for <span class="hlt">motion</span> estimation and image segmentation in sequential Computed Tomography images. Two main tasks are tackled. The first one consists of a method to estimate the heart's <span class="hlt">motion</span> based on a bio-inspired image representation <span class="hlt">model</span>. Our proposal for optical flow estimation incorporates image structure information extracted from the steered Hermite transform coefficients that is later used as local <span class="hlt">motion</span> constraints in a differential estimation approach. The second task deals with cardiac structure segmentation in time series of cardiac images based on deformable <span class="hlt">models</span>. The goal is to extend active shape <span class="hlt">models</span> (ASM) of 2D objects to the problem of 3D (2D + time) cardiac CT image <span class="hlt">modeling</span>. The segmentation is achieved by constructing a point distribution <span class="hlt">model</span> (PDM) that encodes the spatio-temporal variability of a training set. Combination of both <span class="hlt">motion</span> estimation and image segmentation allows isolating <span class="hlt">motion</span> in cardiac structures of medical interest such as ventricle walls.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4024634','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4024634"><span>Elastic network <span class="hlt">models</span> capture the <span class="hlt">motions</span> apparent within ensembles of RNA structures</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Zimmermann, Michael T.; Jernigan, Robert L.</p> <p>2014-01-01</p> <p>The role of structure and dynamics in mechanisms for RNA becomes increasingly important. Computational approaches using simple dynamics <span class="hlt">models</span> have been successful at predicting the <span class="hlt">motions</span> of proteins and are often applied to ribonucleo-protein complexes but have not been thoroughly tested for well-packed nucleic acid structures. In order to characterize a true set of <span class="hlt">motions</span>, we investigate the apparent <span class="hlt">motions</span> from 16 ensembles of experimentally determined RNA structures. These indicate a relatively limited set of <span class="hlt">motions</span> that are captured by a small set of principal components (PCs). These limited <span class="hlt">motions</span> closely resemble the <span class="hlt">motions</span> computed from low frequency normal modes from elastic network <span class="hlt">models</span> (ENMs), either at atomic or coarse-grained resolution. Various ENM <span class="hlt">model</span> types, parameters, and structure representations are tested here against the experimental RNA structural ensembles, exposing differences between <span class="hlt">models</span> for proteins and for folded RNAs. Differences in performance are seen, depending on the structure alignment algorithm used to generate PCs, modulating the apparent utility of ENMs but not significantly impacting their ability to generate functional <span class="hlt">motions</span>. The loss of dynamical information upon coarse-graining is somewhat larger for RNAs than for globular proteins, indicating, perhaps, the lower cooperativity of the less densely packed RNA. However, the RNA structures show less sensitivity to the elastic network <span class="hlt">model</span> parameters than do proteins. These findings further demonstrate the utility of ENMs and the appropriateness of their application to well-packed RNA-only structures, justifying their use for studying the dynamics of ribonucleo-proteins, such as the ribosome and regulatory RNAs. PMID:24759093</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24759093','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24759093"><span>Elastic network <span class="hlt">models</span> capture the <span class="hlt">motions</span> apparent within ensembles of RNA structures.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Zimmermann, Michael T; Jernigan, Robert L</p> <p>2014-06-01</p> <p>The role of structure and dynamics in mechanisms for RNA becomes increasingly important. Computational approaches using simple dynamics <span class="hlt">models</span> have been successful at predicting the <span class="hlt">motions</span> of proteins and are often applied to ribonucleo-protein complexes but have not been thoroughly tested for well-packed nucleic acid structures. In order to characterize a true set of <span class="hlt">motions</span>, we investigate the apparent <span class="hlt">motions</span> from 16 ensembles of experimentally determined RNA structures. These indicate a relatively limited set of <span class="hlt">motions</span> that are captured by a small set of principal components (PCs). These limited <span class="hlt">motions</span> closely resemble the <span class="hlt">motions</span> computed from low frequency normal modes from elastic network <span class="hlt">models</span> (ENMs), either at atomic or coarse-grained resolution. Various ENM <span class="hlt">model</span> types, parameters, and structure representations are tested here against the experimental RNA structural ensembles, exposing differences between <span class="hlt">models</span> for proteins and for folded RNAs. Differences in performance are seen, depending on the structure alignment algorithm used to generate PCs, modulating the apparent utility of ENMs but not significantly impacting their ability to generate functional <span class="hlt">motions</span>. The loss of dynamical information upon coarse-graining is somewhat larger for RNAs than for globular proteins, indicating, perhaps, the lower cooperativity of the less densely packed RNA. However, the RNA structures show less sensitivity to the elastic network <span class="hlt">model</span> parameters than do proteins. These findings further demonstrate the utility of ENMs and the appropriateness of their application to well-packed RNA-only structures, justifying their use for studying the dynamics of ribonucleo-proteins, such as the ribosome and regulatory RNAs. © 2014 Zimmermann and Jernigan; Published by Cold Spring Harbor Laboratory Press for the RNA Society.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1998PMB....43.1385D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1998PMB....43.1385D"><span>A <span class="hlt">model</span> for the fluid <span class="hlt">motion</span> of vitreous humour of the human eye during saccadic movement</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>David, Tim; Smye, Steve; Dabbs, Tim; James, Teifi</p> <p>1998-06-01</p> <p>During saccadic <span class="hlt">motion</span> the eyewall moves in a manner similar to a sinusoid or at least can be represented by a sine Fourier series. <span class="hlt">Motion</span> of the vitreous is induced by the saccade and the vitreo-retinal interface is subjected to a time-dependent shear. This force may be a significant factor for retinal tearing in the neighbourhood of small retinal holes or tears. An analytical viscoelastic <span class="hlt">model</span> and a numerical, Newtonian <span class="hlt">model</span> of the <span class="hlt">motion</span> of the vitreous are presented and compared. Under sinusoidal boundary <span class="hlt">motion</span> the analytical <span class="hlt">model</span> shows that a viscous wave propagates inward toward the axis of rotation and the characteristic length of this wave is a function of the Womersley number. The numerical solution indicates that the vitreous moves similarly to the analytical result with small secondary <span class="hlt">motion</span>; however, this <span class="hlt">motion</span> allows complete recirculation of the vitreous over large timescales. Excellent agreement is found between the analytical and numerical <span class="hlt">models</span>. The time-dependent fluid shear is evaluated and from the analytical solution the maximum value of this is found to be proportional to <IMG SRC="http://ej.iop.org/images/0031-9155/43/6/001/img7.gif" ALIGN="MIDDLE"/>, where <IMG SRC="http://ej.iop.org/images/0031-9155/43/6/001/img8.gif" ALIGN="MIDDLE"/> is the eye radius, <IMG SRC="http://ej.iop.org/images/0031-9155/43/6/001/img9.gif" ALIGN="MIDDLE"/> the modified complex visocosity and <IMG SRC="http://ej.iop.org/images/0031-9155/43/6/001/img10.gif" ALIGN="MIDDLE"/> the sinusoidal frequency. This indicates that myopes have a larger shear force exerted on them by virtue of the larger eye size. Further work is directed toward a <span class="hlt">model</span> which links the stress found in the sclera to that exerted on the vitreo-retinal interface by the vitreous fluid <span class="hlt">motion</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/16154410','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/16154410"><span>Kinematical <span class="hlt">models</span> to reduce the effect of skin artifacts on marker-based human <span class="hlt">motion</span> estimation.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Cerveri, P; Pedotti, A; Ferrigno, G</p> <p>2005-11-01</p> <p>The estimation of the skeletal <span class="hlt">motion</span> obtained from marker-based <span class="hlt">motion</span> capture systems is known to be affected by significant bias caused by skin movement artifacts, which affects joint center and rotation axis estimation. Among different techniques proposed in the literature, that based on rigid body <span class="hlt">model</span>, still the most used by commercial <span class="hlt">motion</span> capture systems, can smooth only part of the above effects without eliminating their main components. In order to sensibly improve the accuracy of the <span class="hlt">motion</span> estimation, a novel technique, named local <span class="hlt">motion</span> estimation (LME), is proposed. This rests on a recently described approach that, using virtual humans and extended Kalman filters, estimates the kinematical variables directly from 2D measurements without requiring the 3D marker reconstruction. In this paper, we show how such method can be extended to include the computation of the local marker displacement due to skin artifacts. The 3D marker coordinates, expressed in the corresponding local reference coordinate frames, are inserted into the state vector of the filter and their dynamics is automatically estimated, with adequate accuracy, without assuming any particular deformation function. Simulated experiments of lower limb <span class="hlt">motion</span>, involving systematic mislocations (5, 10, 20 mm) and random errors of the marker coordinates and joint center locations (+/-5, +/-10, +/-15 mm), have shown that artifact <span class="hlt">motion</span> can be substantially decoupled from the global skeletal <span class="hlt">motion</span> with an effective increase of the accuracy wrt standard techniques. In particular, the comparison between the nominal kinematical variables and the one recovered from markers attached to the skin surface proved LME to be sensibly superior (50% in the worse condition) to the methods imposing marker-bone rigidity. In conclusion, while requiring further validation on real movement data, we argue that the proposed method can constitute an appropriate approach toward the improvement of the human <span class="hlt">motion</span></p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015PhRvE..92e2708D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015PhRvE..92e2708D"><span>Onset of collective <span class="hlt">motion</span> in locusts is captured by a minimal <span class="hlt">model</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Dyson, Louise; Yates, Christian A.; Buhl, Jerome; McKane, Alan J.</p> <p>2015-11-01</p> <p>We present a minimal <span class="hlt">model</span> to describe the onset of collective <span class="hlt">motion</span> seen when a population of locusts are placed in an annular arena. At low densities <span class="hlt">motion</span> is disordered, while at high densities locusts march in a common direction, which may reverse during the experiment. The data are well captured by an individual-based <span class="hlt">model</span>, in which demographic noise leads to the observed density-dependent effects. By fitting the <span class="hlt">model</span> parameters to equation-free coefficients, we give a quantitative comparison, showing time series, stationary distributions, and the mean switching times between states.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011SPIE.7964E..2GC','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011SPIE.7964E..2GC"><span>Creation of 3D digital anthropomorphic phantoms which <span class="hlt">model</span> actual patient non-rigid body <span class="hlt">motion</span> as determined from MRI and position tracking studies of volunteers</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Connolly, C. M.; Konik, A.; Dasari, P. K. R.; Segars, P.; Zheng, S.; Johnson, K. L.; Dey, J.; King, M. A.</p> <p>2011-03-01</p> <p>Patient <span class="hlt">motion</span> can cause artifacts, which can lead to difficulty in interpretation. The purpose of this study is to create 3D digital anthropomorphic phantoms which <span class="hlt">model</span> the location of the structures of the chest and upper abdomen of human volunteers undergoing a series of clinically relevant <span class="hlt">motions</span>. The 3D anatomy is <span class="hlt">modeled</span> using the XCAT phantom and based on MRI studies. The NURBS surfaces of the XCAT are interactively adapted to fit the MRI studies. A detailed XCAT phantom is first developed from an EKG triggered Navigator acquisition composed of sagittal slices with a 3 x 3 x 3 mm voxel dimension. Rigid body <span class="hlt">motion</span> states are then acquired at breath-hold as sagittal slices partially covering the thorax, centered on the heart, with 9 mm gaps between them. For non-rigid body <span class="hlt">motion</span> requiring greater sampling, modified Navigator sequences covering the entire thorax with 3 mm gaps between slices are obtained. The structures of the initial XCAT are then adapted to fit these different <span class="hlt">motion</span> states. Simultaneous to MRI imaging the positions of <span class="hlt">multiple</span> reflective markers on stretchy bands about the volunteer's chest and abdomen are optically tracked in 3D via stereo imaging. These phantoms with combined position tracking will be used to investigate both imaging-data-driven and <span class="hlt">motion</span>-tracking strategies to estimate and correct for patient <span class="hlt">motion</span>. Our initial application will be to cardiacperfusion SPECT imaging where the XCAT phantoms will be used to create patient activity and attenuation distributions for each volunteer with corresponding <span class="hlt">motion</span> tracking data from the markers on the body-surface. Monte Carlo methods will then be used to simulate SPECT acquisitions, which will be used to evaluate various <span class="hlt">motion</span> estimation and correction strategies.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013SPIE.8671E..0SN','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013SPIE.8671E..0SN"><span>A patient specific 4D MRI liver <span class="hlt">motion</span> <span class="hlt">model</span> based on sparse imaging and registration</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Noorda, Y. H.; Bartels, L. W.; van Stralen, Marijn; Pluim, J. P. W.</p> <p>2013-03-01</p> <p><strong>Introduction:</strong> Image-guided minimally invasive procedures are becoming increasingly popular. Currently, High-Intensity Focused Ultrasound (HIFU) treatment of lesions in mobile organs, such as the liver, is in development. A requirement for such treatment is automatic <span class="hlt">motion</span> tracking, such that the position of the lesion can be followed in real time. We propose a 4D liver <span class="hlt">motion</span> <span class="hlt">model</span>, which can be used during planning of this procedure. During treatment, the <span class="hlt">model</span> can serve as a <span class="hlt">motion</span> predictor. In a similar fashion, this <span class="hlt">model</span> could be used for radiotherapy treatment of the liver. <strong>Method:</strong> The <span class="hlt">model</span> is built by acquiring 2D dynamic sagittal MRI data at six locations in the liver. By registering these dynamics to a 3D MRI liver image, 2D deformation fields are obtained at every location. The 2D fields are ordered according to the position of the liver at that specific time point, such that liver <span class="hlt">motion</span> during an average breathing period can be simulated. This way, a sparse deformation field is created over time. This deformation field is finally interpolated over the entire volume, yielding a 4D <span class="hlt">motion</span> <span class="hlt">model</span>. <strong>Results:</strong> The accuracy of the <span class="hlt">model</span> is evaluated by comparing unseen slices to the slice predicted by the <span class="hlt">model</span> at that specific location and phase in the breathing cycle. The mean Dice coefficient of the liver regions was 0.90. The mean misalignment of the vessels was 1.9 mm.<strong> Conclusion</strong>: The <span class="hlt">model</span> is able to predict patient specific deformations of the liver and can predict regular <span class="hlt">motion</span> accurately.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24612709','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24612709"><span>Viscoelastic <span class="hlt">model</span> based force control for soft tissue interaction and its application in physiological <span class="hlt">motion</span> compensation.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Moreira, Pedro; Zemiti, Nabil; Liu, Chao; Poignet, Philippe</p> <p>2014-09-01</p> <p>Controlling the interaction between robots and living soft tissues has become an important issue as the number of robotic systems inside the operating room increases. Many researches have been done on force control to help surgeons during medical procedures, such as physiological <span class="hlt">motion</span> compensation and tele-operation systems with haptic feedback. In order to increase the performance of such controllers, this work presents a novel force control scheme using Active Observer (AOB) based on a viscoelastic interaction <span class="hlt">model</span>. The control scheme has shown to be stable through theoretical analysis and its performance was evaluated by in vitro experiments. In order to evaluate how the force control scheme behaves under the presence of physiological <span class="hlt">motion</span>, experiments considering breathing and beating heart disturbances are presented. The proposed control scheme presented a stable behavior in both static and moving environment. The viscoelastic AOB presented a compensation ratio of 87% for the breathing <span class="hlt">motion</span> and 79% for the beating heart <span class="hlt">motion</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.dtic.mil/docs/citations/ADA439819','DTIC-ST'); return false;" href="http://www.dtic.mil/docs/citations/ADA439819"><span><span class="hlt">Modeling</span>, Simulation and Performance Analysis of <span class="hlt">Multiple</span>-Input <span class="hlt">Multiple</span>-Output (MIMO) Systems with Multicarrier Time Delay Diversity Modulation</span></a></p> <p><a target="_blank" href="http://www.dtic.mil/">DTIC Science & Technology</a></p> <p></p> <p>2005-09-01</p> <p><span class="hlt">MULTIPLE</span> - INPUT <span class="hlt">MULTIPLE</span> - OUTPUT ( MIMO ) SYSTEMS WITH MULTICARRIER TIME DELAY DIVERSITY MODULATION by Muhammad...SUBTITLE: <span class="hlt">Modeling</span>, Simulation and Performance Analysis of <span class="hlt">Multiple</span> - Input <span class="hlt">Multiple</span> - Output ( MIMO ) Systems with Multicarrier Time Delay Diversity Modulation...MISO) and <span class="hlt">multiple</span> - input <span class="hlt">multiple</span> - output ( MIMO ) radio communication systems with space-time codes. A MISO system and MIMO</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=66962&keyword=biometrics&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50&CFID=78676012&CFTOKEN=86770661','EPA-EIMS'); return false;" href="http://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=66962&keyword=biometrics&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50&CFID=78676012&CFTOKEN=86770661"><span>MULTIVARIATE LINEAR MIXED <span class="hlt">MODELS</span> FOR <span class="hlt">MULTIPLE</span> OUTCOMES. (R824757)</span></a></p> <p><a target="_blank" href="http://oaspub.epa.gov/eims/query.page">EPA Science Inventory</a></p> <p></p> <p></p> <p>We propose a multivariate linear mixed (MLMM) for the analysis of <span class="hlt">multiple</span> outcomes, which generalizes the latent variable <span class="hlt">model</span> of Sammel and Ryan. The proposed <span class="hlt">model</span> assumes a flexible correlation structure among the <span class="hlt">multiple</span> outcomes, and allows a global test of the impact of ...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=66962&keyword=biometrics&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50','EPA-EIMS'); return false;" href="http://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=66962&keyword=biometrics&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50"><span>MULTIVARIATE LINEAR MIXED <span class="hlt">MODELS</span> FOR <span class="hlt">MULTIPLE</span> OUTCOMES. (R824757)</span></a></p> <p><a target="_blank" href="http://oaspub.epa.gov/eims/query.page">EPA Science Inventory</a></p> <p></p> <p></p> <p>We propose a multivariate linear mixed (MLMM) for the analysis of <span class="hlt">multiple</span> outcomes, which generalizes the latent variable <span class="hlt">model</span> of Sammel and Ryan. The proposed <span class="hlt">model</span> assumes a flexible correlation structure among the <span class="hlt">multiple</span> outcomes, and allows a global test of the impact of ...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://eric.ed.gov/?q=Marc+AND+jacobs&id=EJ734781','ERIC'); return false;" href="https://eric.ed.gov/?q=Marc+AND+jacobs&id=EJ734781"><span>Testing the <span class="hlt">Multiple</span> in the <span class="hlt">Multiple</span> Read-Out <span class="hlt">Model</span> of Visual Word Recognition</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>De Moor, Wendy; Verguts, Tom; Brysbaert, Marc</p> <p>2005-01-01</p> <p>This study provided a test of the <span class="hlt">multiple</span> criteria concept used for lexical decision, as implemented in J. Grainger and A. M. Jacobs's (1996) <span class="hlt">multiple</span> read-out <span class="hlt">model</span>. This account predicts more inhibition (or less facilitation) from a masked neighbor when accuracy is stressed more but more facilitation (or less inhibition) when the speed of…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=Tom+AND+Jacobs&id=EJ734781','ERIC'); return false;" href="http://eric.ed.gov/?q=Tom+AND+Jacobs&id=EJ734781"><span>Testing the <span class="hlt">Multiple</span> in the <span class="hlt">Multiple</span> Read-Out <span class="hlt">Model</span> of Visual Word Recognition</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>De Moor, Wendy; Verguts, Tom; Brysbaert, Marc</p> <p>2005-01-01</p> <p>This study provided a test of the <span class="hlt">multiple</span> criteria concept used for lexical decision, as implemented in J. Grainger and A. M. Jacobs's (1996) <span class="hlt">multiple</span> read-out <span class="hlt">model</span>. This account predicts more inhibition (or less facilitation) from a masked neighbor when accuracy is stressed more but more facilitation (or less inhibition) when the speed of…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25751452','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25751452"><span>A three-dimensional ankle kinetostatic <span class="hlt">model</span> to simulate loaded and unloaded joint <span class="hlt">motion</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Forlani, Margherita; Sancisi, Nicola; Parenti-Castelli, Vincenzo</p> <p>2015-06-01</p> <p>A kinetostatic <span class="hlt">model</span> able to replicate both the natural unloaded <span class="hlt">motion</span> of the tibiotalar (or ankle) joint and the joint behavior under external loads is presented. The <span class="hlt">model</span> is developed as the second step of a sequential procedure, which allows the definition of a kinetostatic <span class="hlt">model</span> as a generalization of a kinematic <span class="hlt">model</span> of the joint defined at the first step. Specifically, this kinematic <span class="hlt">model</span> taken as the starting point of the definition procedure is a parallel spatial mechanism which replicates the ankle unloaded <span class="hlt">motion</span>. It features two rigid bodies (representing the tibia-fibula and the talus-calcaneus complexes) interconnected by five rigid binary links, that mimic three articular contacts and two nearly isometric fibers (IFs) of the tibiocalcaneal ligament (TiCaL) and calcaneofibular ligament (CaFiL). In the kinetostatic <span class="hlt">model</span>, the five links are considered as compliant; moreover, further elastic structures are added to represent all the main ankle passive structures of the joint. Thanks to this definition procedure, the kinetostatic <span class="hlt">model</span> still replicates the ankle unloaded <span class="hlt">motion</span> with the same accuracy as the kinematic <span class="hlt">model</span>. In addition, the <span class="hlt">model</span> can replicate the behavior of the joint when external loads are applied. Finally, the structures that guide these <span class="hlt">motions</span> are consistent with the anatomical evidence. The parameters of the <span class="hlt">model</span> are identified for two specimens from both subject-specific and published data. Loads are then applied to the <span class="hlt">model</span> in order to simulate two common clinical tests. The <span class="hlt">model</span>-predicted ankle <span class="hlt">motion</span> shows good agreement with results from the literature.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/20726235','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/20726235"><span>The application of the sinusoidal <span class="hlt">model</span> to lung cancer patient respiratory <span class="hlt">motion</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>George, R.; Vedam, S.S.; Chung, T.D.; Ramakrishnan, V.; Keall, P.J.</p> <p>2005-09-15</p> <p>Accurate <span class="hlt">modeling</span> of the respiratory cycle is important to account for the effect of organ <span class="hlt">motion</span> on dose calculation for lung cancer patients. The aim of this study is to evaluate the accuracy of a respiratory <span class="hlt">model</span> for lung cancer patients. Lujan et al. [Med. Phys. 26(5), 715-720 (1999)] proposed a <span class="hlt">model</span>, which became widely used, to describe organ <span class="hlt">motion</span> due to respiration. This <span class="hlt">model</span> assumes that the parameters do not vary between and within breathing cycles. In this study, first, the correlation of respiratory <span class="hlt">motion</span> traces with the <span class="hlt">model</span> f(t) as a function of the parameter n(n=1,2,3) was undertaken for each breathing cycle from 331 four-minute respiratory traces acquired from 24 lung cancer patients using three breathing types: free breathing, audio instruction, and audio-visual biofeedback. Because cos{sup 2} and cos{sup 4} had similar correlation coefficients, and cos{sup 2} and cos{sup 1} have a trigonometric relationship, for simplicity, the cos{sup 1} value was consequently used for further analysis in which the variations in mean position (z{sub 0}), amplitude of <span class="hlt">motion</span> (b) and period ({tau}) with and without biofeedback or instructions were investigated. For all breathing types, the parameter values, mean position (z{sub 0}), amplitude of <span class="hlt">motion</span> (b), and period ({tau}) exhibited significant cycle-to-cycle variations. Audio-visual biofeedback showed the least variations for all three parameters (z{sub 0}, b, and {tau}). It was found that mean position (z{sub 0}) could be approximated with a normal distribution, and the amplitude of <span class="hlt">motion</span> (b) and period ({tau}) could be approximated with log normal distributions. The overall probability density function (pdf) of f(t) for each of the three breathing types was fitted with three <span class="hlt">models</span>: normal, bimodal, and the pdf of a simple harmonic oscillator. It was found that the normal and the bimodal <span class="hlt">models</span> represented the overall respiratory <span class="hlt">motion</span> pdfs with correlation values from 0.95 to 0.99, whereas the range</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016OPhy...14...19H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016OPhy...14...19H"><span>Flap <span class="hlt">motion</span> of helicopter rotors with novel, dynamic stall <span class="hlt">model</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Han, Wei; Liu, Jie; Liu, Chun; Chen, Lei; Su, Xichao; Zhao, Peng</p> <p>2016-01-01</p> <p>In this paper, a nonlinear flapping equation for large inflow angles and flap angles is established by analyzing the aerodynamics of helicopter blade elements. In order to obtain a generalized flap equation, the Snel stall <span class="hlt">model</span> was first applied to determine the lift coefficient of the helicopter rotor. A simulation experiment for specific airfoils was then conducted to verify the effectiveness of the Snel stall <span class="hlt">model</span> as it applies to helicopters. Results show that the <span class="hlt">model</span> requires no extraneous parameters compared to the traditional stall <span class="hlt">model</span> and is highly accurate and practically applicable. Based on the <span class="hlt">model</span>, the relationship between the flapping angle and the angle of attack was analyzed, as well as the advance ratio under the dynamic stall state.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li class="active"><span>23</span></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_23 --> <div id="page_24" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li class="active"><span>24</span></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="461"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/22167783','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/22167783"><span>ROTATING <span class="hlt">MOTIONS</span> AND <span class="hlt">MODELING</span> OF THE ERUPTING SOLAR POLAR-CROWN PROMINENCE ON 2010 DECEMBER 6</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Su, Yingna; Van Ballegooijen, Adriaan</p> <p>2013-02-10</p> <p>A large polar-crown prominence composed of different segments spanning nearly the entire solar disk erupted on 2010 December 6. Prior to the eruption, the filament in the active region part split into two layers: a lower layer and an elevated layer. The eruption occurs in several episodes. Around 14:12 UT, the lower layer of the active region filament breaks apart: One part ejects toward the west, while the other part ejects toward the east, which leads to the explosive eruption of the eastern quiescent filament. During the early rise phase, part of the quiescent filament sheet displays strong rolling <span class="hlt">motion</span> (observed by STEREO-B) in the clockwise direction (viewed from east to west) around the filament axis. This rolling <span class="hlt">motion</span> appears to start from the border of the active region, then propagates toward the east. The Atmospheric Imaging Assembly (AIA) observes another type of rotating <span class="hlt">motion</span>: In some other parts of the erupting quiescent prominence, the vertical threads turn horizontal, then turn upside down. The elevated active region filament does not erupt until 18:00 UT, when the erupting quiescent filament has already reached a very large height. We develop two simplified three-dimensional <span class="hlt">models</span> that qualitatively reproduce the observed rolling and rotating <span class="hlt">motions</span>. The prominence in the <span class="hlt">models</span> is assumed to consist of a collection of discrete blobs that are tied to particular field lines of a helical flux rope. The observed rolling <span class="hlt">motion</span> is reproduced by continuous twist injection into the flux rope in <span class="hlt">Model</span> 1 from the active region side. Asymmetric reconnection induced by the asymmetric distribution of the magnetic fields on the two sides of the filament may cause the observed rolling <span class="hlt">motion</span>. The rotating <span class="hlt">motion</span> of the prominence threads observed by AIA is consistent with the removal of the field line dips in <span class="hlt">Model</span> 2 from the top down during the eruption.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70026016','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70026016"><span>Strong ground-<span class="hlt">motion</span> prediction from Stochastic-dynamic source <span class="hlt">models</span></span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Guatteri, Mariagiovanna; Mai, P.M.; Beroza, G.C.; Boatwright, J.</p> <p>2003-01-01</p> <p>In the absence of sufficient data in the very near source, predictions of the intensity and variability of ground <span class="hlt">motions</span> from future large earthquakes depend strongly on our ability to develop realistic <span class="hlt">models</span> of the earthquake source. In this article we simulate near-fault strong ground <span class="hlt">motion</span> using dynamic source <span class="hlt">models</span>. We use a boundary integral method to simulate dynamic rupture of earthquakes by specifying dynamic source parameters (fracture energy and stress drop) as spatial random fields. We choose these quantities such that they are consistent with the statistical properties of slip heterogeneity found in finite-source <span class="hlt">models</span> of past earthquakes. From these rupture <span class="hlt">models</span> we compute theoretical strong-<span class="hlt">motion</span> seismograms up to a frequency of 2 Hz for several realizations of a scenario strike-slip Mw 7.0 earthquake and compare empirical response spectra, spectra obtained from our dynamic <span class="hlt">models</span>, and spectra determined from corresponding kinematic simulations. We find that spatial and temporal variations in slip, slip rise time, and rupture propagation consistent with dynamic rupture <span class="hlt">models</span> exert a strong influence on near-source ground <span class="hlt">motion</span>. Our results lead to a feasible approach to specify the variability in the rupture time distribution in kinematic <span class="hlt">models</span> through a generalization of Andrews' (1976) result relating rupture speed to apparent fracture energy, stress drop, and crack length to 3D dynamic <span class="hlt">models</span>. This suggests that a simplified representation of dynamic rupture may be obtained to approximate the effects of dynamic rupture without having to do full dynamic simulations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012PMB....57.2539L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012PMB....57.2539L"><span>Evaluation of deformable image registration and a <span class="hlt">motion</span> <span class="hlt">model</span> in CT images with limited features</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Liu, F.; Hu, Y.; Zhang, Q.; Kincaid, R.; Goodman, K. A.; Mageras, G. S.</p> <p>2012-05-01</p> <p>Deformable image registration (DIR) is increasingly used in radiotherapy applications and provides the basis for a previously described <span class="hlt">model</span> of patient-specific respiratory <span class="hlt">motion</span>. We examine the accuracy of a DIR algorithm and a <span class="hlt">motion</span> <span class="hlt">model</span> with respiration-correlated CT (RCCT) images of software phantom with known displacement fields, physical deformable abdominal phantom with implanted fiducials in the liver and small liver structures in patient images. The <span class="hlt">motion</span> <span class="hlt">model</span> is derived from a principal component analysis that relates volumetric deformations with the <span class="hlt">motion</span> of the diaphragm or fiducials in the RCCT. Patient data analysis compares DIR with rigid registration as ground truth: the mean ± standard deviation 3D discrepancy of liver structure centroid positions is 2.0 ± 2.2 mm. DIR discrepancy in the software phantom is 3.8 ± 2.0 mm in lung and 3.7 ± 1.8 mm in abdomen; discrepancies near the chest wall are larger than indicated by image feature matching. Marker's 3D discrepancy in the physical phantom is 3.6 ± 2.8 mm. The results indicate that visible features in the images are important for guiding the DIR algorithm. <span class="hlt">Motion</span> <span class="hlt">model</span> accuracy is comparable to DIR, indicating that two principal components are sufficient to describe DIR-derived deformation in these datasets.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24008129','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24008129"><span>Mathematical analysis and <span class="hlt">modeling</span> of <span class="hlt">motion</span> direction selectivity in the retina.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Escobar, María-José; Pezo, Danilo; Orio, Patricio</p> <p>2013-11-01</p> <p><span class="hlt">Motion</span> detection is one of the most important and primitive computations performed by our visual system. Specifically in the retina, ganglion cells producing <span class="hlt">motion</span> direction-selective responses have been addressed by different disciplines, such as mathematics, neurophysiology and computational <span class="hlt">modeling</span>, since the beginnings of vision science. Although a number of studies have analyzed theoretical and mathematical considerations for such responses, a clear picture of the underlying cellular mechanisms is only recently emerging. In general, <span class="hlt">motion</span> direction selectivity is based on a non-linear asymmetric computation inside a receptive field differentiating cell responses between preferred and null direction stimuli. To what extent can biological findings match these considerations? In this review, we outline theoretical and mathematical studies of <span class="hlt">motion</span> direction selectivity, aiming to map the properties of the <span class="hlt">models</span> onto the neural circuitry and synaptic connectivity found in the retina. Additionally, we review several compartmental <span class="hlt">models</span> that have tried to fill this gap. Finally, we discuss the remaining challenges that computational <span class="hlt">models</span> will have to tackle in order to fully understand the retinal <span class="hlt">motion</span> direction-selective circuitry. Copyright © 2013 Elsevier Ltd. All rights reserved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24892103','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24892103"><span>Moving object detection using dynamic <span class="hlt">motion</span> <span class="hlt">modelling</span> from UAV aerial images.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Saif, A F M Saifuddin; Prabuwono, Anton Satria; Mahayuddin, Zainal Rasyid</p> <p>2014-01-01</p> <p><span class="hlt">Motion</span> analysis based moving object detection from UAV aerial image is still an unsolved issue due to inconsideration of proper <span class="hlt">motion</span> estimation. Existing moving object detection approaches from UAV aerial images did not deal with <span class="hlt">motion</span> based pixel intensity measurement to detect moving object robustly. Besides current research on moving object detection from UAV aerial images mostly depends on either frame difference or segmentation approach separately. There are two main purposes for this research: firstly to develop a new <span class="hlt">motion</span> <span class="hlt">model</span> called DMM (dynamic <span class="hlt">motion</span> <span class="hlt">model</span>) and secondly to apply the proposed segmentation approach SUED (segmentation using edge based dilation) using frame difference embedded together with DMM <span class="hlt">model</span>. The proposed DMM <span class="hlt">model</span> provides effective search windows based on the highest pixel intensity to segment only specific area for moving object rather than searching the whole area of the frame using SUED. At each stage of the proposed scheme, experimental fusion of the DMM and SUED produces extracted moving objects faithfully. Experimental result reveals that the proposed DMM and SUED have successfully demonstrated the validity of the proposed methodology.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4032674','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4032674"><span>Moving Object Detection Using Dynamic <span class="hlt">Motion</span> <span class="hlt">Modelling</span> from UAV Aerial Images</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Saif, A. F. M. Saifuddin; Prabuwono, Anton Satria; Mahayuddin, Zainal Rasyid</p> <p>2014-01-01</p> <p><span class="hlt">Motion</span> analysis based moving object detection from UAV aerial image is still an unsolved issue due to inconsideration of proper <span class="hlt">motion</span> estimation. Existing moving object detection approaches from UAV aerial images did not deal with <span class="hlt">motion</span> based pixel intensity measurement to detect moving object robustly. Besides current research on moving object detection from UAV aerial images mostly depends on either frame difference or segmentation approach separately. There are two main purposes for this research: firstly to develop a new <span class="hlt">motion</span> <span class="hlt">model</span> called DMM (dynamic <span class="hlt">motion</span> <span class="hlt">model</span>) and secondly to apply the proposed segmentation approach SUED (segmentation using edge based dilation) using frame difference embedded together with DMM <span class="hlt">model</span>. The proposed DMM <span class="hlt">model</span> provides effective search windows based on the highest pixel intensity to segment only specific area for moving object rather than searching the whole area of the frame using SUED. At each stage of the proposed scheme, experimental fusion of the DMM and SUED produces extracted moving objects faithfully. Experimental result reveals that the proposed DMM and SUED have successfully demonstrated the validity of the proposed methodology. PMID:24892103</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1249136','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1249136"><span>Validation of attenuation <span class="hlt">models</span> for ground <span class="hlt">motion</span> applications in central and eastern North America</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Pasyanos, Michael E.</p> <p>2015-11-01</p> <p>Recently developed attenuation <span class="hlt">models</span> are incorporated into standard one-dimensional (1-D) ground <span class="hlt">motion</span> prediction equations (GMPEs), effectively making them two-dimensional (2-D) and eliminating the need to create different GMPEs for an increasing number of sub-regions. The <span class="hlt">model</span> is tested against a data set of over 10,000 recordings from 81 earthquakes in North America. The use of attenuation <span class="hlt">models</span> in GMPEs improves our ability to fit observed ground <span class="hlt">motions</span> and should be incorporated into future national hazard maps. The improvement is most significant at higher frequencies and longer distances which have a greater number of wave cycles. This has implications for the rare high-magnitude earthquakes, which produce potentially damaging ground <span class="hlt">motions</span> over wide areas, and drive the seismic hazards. Furthermore, the attenuation <span class="hlt">models</span> can be created using weak ground <span class="hlt">motions</span>, they could be developed for regions of low seismicity where empirical recordings of ground <span class="hlt">motions</span> are uncommon and do not span the full range of magnitudes and distances.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/pages/biblio/1249136-validation-attenuation-models-ground-motion-applications-central-eastern-north-america','SCIGOV-DOEP'); return false;" href="https://www.osti.gov/pages/biblio/1249136-validation-attenuation-models-ground-motion-applications-central-eastern-north-america"><span>Validation of attenuation <span class="hlt">models</span> for ground <span class="hlt">motion</span> applications in central and eastern North America</span></a></p> <p><a target="_blank" href="http://www.osti.gov/pages">DOE PAGES</a></p> <p>Pasyanos, Michael E.</p> <p>2015-11-01</p> <p>Recently developed attenuation <span class="hlt">models</span> are incorporated into standard one-dimensional (1-D) ground <span class="hlt">motion</span> prediction equations (GMPEs), effectively making them two-dimensional (2-D) and eliminating the need to create different GMPEs for an increasing number of sub-regions. The <span class="hlt">model</span> is tested against a data set of over 10,000 recordings from 81 earthquakes in North America. The use of attenuation <span class="hlt">models</span> in GMPEs improves our ability to fit observed ground <span class="hlt">motions</span> and should be incorporated into future national hazard maps. The improvement is most significant at higher frequencies and longer distances which have a greater number of wave cycles. This has implications for themore » rare high-magnitude earthquakes, which produce potentially damaging ground <span class="hlt">motions</span> over wide areas, and drive the seismic hazards. Furthermore, the attenuation <span class="hlt">models</span> can be created using weak ground <span class="hlt">motions</span>, they could be developed for regions of low seismicity where empirical recordings of ground <span class="hlt">motions</span> are uncommon and do not span the full range of magnitudes and distances.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26809812','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26809812"><span><span class="hlt">Multiple</span> imputation of <span class="hlt">multiple</span> multi-item scales when a full imputation <span class="hlt">model</span> is infeasible.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Plumpton, Catrin O; Morris, Tim; Hughes, Dyfrig A; White, Ian R</p> <p>2016-01-26</p> <p>Missing data in a large scale survey presents major challenges. We focus on performing <span class="hlt">multiple</span> imputation by chained equations when data contain <span class="hlt">multiple</span> incomplete multi-item scales. Recent authors have proposed imputing such data at the level of the individual item, but this can lead to infeasibly large imputation <span class="hlt">models</span>. We use data gathered from a large multinational survey, where analysis uses separate logistic regression <span class="hlt">models</span> in each of nine country-specific data sets. In these data, applying <span class="hlt">multiple</span> imputation by chained equations to the individual scale items is computationally infeasible. We propose an adaptation of <span class="hlt">multiple</span> imputation by chained equations which imputes the individual scale items but reduces the number of variables in the imputation <span class="hlt">models</span> by replacing most scale items with scale summary scores. We evaluate the feasibility of the proposed approach and compare it with a complete case analysis. We perform a simulation study to compare the proposed method with alternative approaches: we do this in a simplified setting to allow comparison with the full imputation <span class="hlt">model</span>. For the case study, the proposed approach reduces the size of the prediction <span class="hlt">models</span> from 134 predictors to a maximum of 72 and makes <span class="hlt">multiple</span> imputation by chained equations computationally feasible. Distributions of imputed data are seen to be consistent with observed data. Results from the regression analysis with <span class="hlt">multiple</span> imputation are similar to, but more precise than, results for complete case analysis; for the same regression <span class="hlt">models</span> a 39% reduction in the standard error is observed. The simulation shows that our proposed method can perform comparably against the alternatives. By substantially reducing imputation <span class="hlt">model</span> sizes, our adaptation makes <span class="hlt">multiple</span> imputation feasible for large scale survey data with <span class="hlt">multiple</span> multi-item scales. For the data considered, analysis of the multiply imputed data shows greater power and efficiency than complete case analysis. The</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4032399','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4032399"><span>Patient specific respiratory <span class="hlt">motion</span> <span class="hlt">modeling</span> using a 3D patient’s external surface</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Fayad, Hadi; Pan, Tinsu; Pradier, Olivier; Visvikis, Dimitris</p> <p>2012-01-01</p> <p>Purpose: Respiratory <span class="hlt">motion</span> <span class="hlt">modeling</span> of both tumor and surrounding tissues is a key element in minimizing errors and uncertainties in radiation therapy. Different continuous <span class="hlt">motion</span> <span class="hlt">models</span> have been previously developed. However, most of these <span class="hlt">models</span> are based on the use of parameters such as amplitude and phase extracted from 1D external respiratory signal. A potentially reduced correlation between the internal structures (tumor and healthy organs) and the corresponding external surrogates obtained from such 1D respiratory signal is a limitation of these <span class="hlt">models</span>. The objective of this work is to describe a continuous patient specific respiratory <span class="hlt">motion</span> <span class="hlt">model</span>, accounting for the irregular nature of respiratory signals, using patient external surface information as surrogate measures rather than a 1D respiratory signal. Methods: Ten patients were used in this study having each one 4D CT series, a synchronized RPM signal and patient surfaces extracted from the 4D CT volumes using a threshold based segmentation algorithm. A patient specific <span class="hlt">model</span> based on the use of principal component analysis was subsequently constructed. This <span class="hlt">model</span> relates the internal <span class="hlt">motion</span> described by deformation matrices and the external <span class="hlt">motion</span> characterized by the amplitude and the phase of the respiratory signal in the case of the RPM or using specific regions of interest (ROI) in the case of the patients’