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Sample records for active kinematic constraint

  1. THE EFFECT OF AN ACUTE BOUT OF RUBBER TUBE RUNNING CONSTRAINT ON KINEMATICS AND MUSCLE ACTIVITY

    Directory of Open Access Journals (Sweden)

    Anita Haudum

    2012-09-01

    Full Text Available We examined the effect of an acute bout of treadmill running with rubber tube (RT and without rubber tube (NT elastic constraints on electromyographic (EMG, 3D kinematics variability, and blood lactate concentration (LA. In the RT test, the constraints were attached to the hips and ankles. The selected variables were compared between 30 min of NT running and 30 minutes of RT running in 13 healthy recreationally trained male runners who had no prior exposure to RT. Statistical analysis revealed significantly higher EMG variability (p < 0.01 and muscle activity (p < 0.05 during RT compared to NT that decreased over time approaching NT, indicating movement pattern adaptation. 3D-kinematics and their variability remained generally unaltered. Changes occurred predominantly in the sagittal plane, specifically to the knee and the swing. A significant increase in LA was measured at the end of RT (p < 0.05. These findings suggest that RT running influences muscle recruitment and variability, but has only a minor influence on kinematics. Changes in LA were significant, although relatively small. The observed adaptations in EMG and kinematics suggest that the RTs provide a possibility to create within movement variability in various sports, and thus, variable training conditions may foster strategies to increase the ability to flexibly adapt to different and new situations

  2. New Constraints on the Geometry and Kinematics of Active Faults in the Hinterland of the Northwest Himalaya

    Science.gov (United States)

    Morell, K. D.; Sandiford, M.; Rajendran, C. C. P.; Fink, D.; Kohn, B. P.

    2014-12-01

    The geometry and kinematics of the active, and potentially seismogenic, fault structures within the hinterland of the Himalaya have proven challenging to constrain in the past, primarily because active faults in this region tend to be buried beneath the subsurface and active seismicity often does not align with surficially mapped fault traces. Here we present a series of complementary datasets, including results from low temperature thermochronology, basin-wide erosion rates from 10Be concentrations, and topographic and longitudinal profile analyses, that place constraints on the spatial distribution of fault-related rock uplift and erosion across a ~400-km long region of the lower and high Himalaya of northwest India. Results from our analyses reveal that hillslope morphology and channel steepness are relatively invariant parallel to strike but vary significantly across strike, with the most prominent and abrupt variations occurring at the physiographic transition between the lower and high Himalaya (PT2), near the axial trace of the ramp-flat transition in the Main Himalayan Thrust (MHT). The cross-strike changes in geomorphology observed across the PT2 correlate with an order of magnitude northward increase in basin-wide erosion rates (~0.06-0.8 mm/a) and a corresponding decrease in apatite (~5-2 Ma) and zircon (U-Th)/He (~10-2 Ma) cooling ages. Combined with published geophysical and seismicity data, we interpret these results to reflect spatial variations in rock uplift and exhumation induced by a segment of the MHT ramp-flat system that is at least ~400 km long and ~125 km wide. The relatively young (U-Th)/He ages (flat transition preliminarily suggest that the kinematics of this system are best explained by a model which incorporates an accreting duplex on the MHT ramp but additional forthcoming analyses, including thermal modeling, will confirm if this hypothesis is robust.

  3. GNSS Precise Kinematic Positioning for Multiple Kinematic Stations Based on A Priori Distance Constraints

    Directory of Open Access Journals (Sweden)

    Kaifei He

    2016-04-01

    Full Text Available When applying the Global Navigation Satellite System (GNSS for precise kinematic positioning in airborne and shipborne gravimetry, multiple GNSS receiving equipment is often fixed mounted on the kinematic platform carrying the gravimetry instrumentation. Thus, the distances among these GNSS antennas are known and invariant. This information can be used to improve the accuracy and reliability of the state estimates. For this purpose, the known distances between the antennas are applied as a priori constraints within the state parameters adjustment. These constraints are introduced in such a way that their accuracy is taken into account. To test this approach, GNSS data of a Baltic Sea shipborne gravimetric campaign have been used. The results of our study show that an application of distance constraints improves the accuracy of the GNSS kinematic positioning, for example, by about 4 mm for the radial component.

  4. GNSS Precise Kinematic Positioning for Multiple Kinematic Stations Based on A Priori Distance Constraints.

    Science.gov (United States)

    He, Kaifei; Xu, Tianhe; Förste, Christoph; Petrovic, Svetozar; Barthelmes, Franz; Jiang, Nan; Flechtner, Frank

    2016-04-01

    When applying the Global Navigation Satellite System (GNSS) for precise kinematic positioning in airborne and shipborne gravimetry, multiple GNSS receiving equipment is often fixed mounted on the kinematic platform carrying the gravimetry instrumentation. Thus, the distances among these GNSS antennas are known and invariant. This information can be used to improve the accuracy and reliability of the state estimates. For this purpose, the known distances between the antennas are applied as a priori constraints within the state parameters adjustment. These constraints are introduced in such a way that their accuracy is taken into account. To test this approach, GNSS data of a Baltic Sea shipborne gravimetric campaign have been used. The results of our study show that an application of distance constraints improves the accuracy of the GNSS kinematic positioning, for example, by about 4 mm for the radial component.

  5. Inverse Kinematic Control of Humanoids Under Joint Constraints

    Directory of Open Access Journals (Sweden)

    Inhyeok Kim

    2013-01-01

    Full Text Available We propose an inverse kinematic control framework for a position controlled humanoid robot with bounded joint range, velocity, and acceleration limits. The proposed framework comprises two components, an inverse kinematics algorithm and a damping controller. The proposed IKTC (Inverse Kinematics with Task Corrections algorithm is based on the second order task‐ priority method in order to ensure the velocity‐continuity of the solution. When the minimum norm solution exceeds the joint bounds, the problem is treated as a quadratic optimization problem with box constraints; an optimal task correction that lets the solution satisfy the constraints is found. In order to express the three kinds of joint constraints as a second order box constraint, a novel method is also proposed. The joint stiffness of a position controlled humanoid robot necessitates a damping controller to attenuate jolts caused by repeated contacts. We design a damping controller by using an inverted pendulum model with a compliant joint that takes into account the compliance around the foot. By using ZMP [20] measurement, the proposed damping controller is applicable not only in SSP (Single Support Phase but also in DSP (Double Support Phase. The validity of the proposed methods is shown by imitating a captured whole‐body human motion with a position controlled humanoid robot.

  6. Kinematic analysis of recent and active faults of the southern Umbria-Marche domain, Northern Apennines, Italy: geological constraints to geodynamic models

    Science.gov (United States)

    Pasqui, Valeria; Viti, Marcello; Mantovani, Enzo

    2013-04-01

    The recent and active deformation that affects the crest zone of the Umbria-Marche belt (Northern Apennines, Italy) displays a remarkable extensional character, outlined by development of normal fault sets that overprint pre-existing folds and thrusts of Late Miocene-Early Pliocene age. The main extensional fault systems often bound intermontane depressions hosting recent, mainly continental, i.e. fluvial or lacustrine deposits, separating the latter from Triassic-Miocene, mainly carbonatic and siliciclastic marine rocks that belong to the Romagna-Umbria-Marche stratigraphic succession. Stratigraphic data indicate that the extensional strain responsible for the development of normal fault-bounded continental basins in the outer zones of the Northern Apennines was active until Middle Pleistocene time. Since Middle Pleistocene time onwards a major geodynamic change has affected the Central Mediterranean region, with local reorganization of the kinematics in the Adria domain and adjacent Apennine belt. A wide literature illustrates that the overall deformation field of the Central Mediterranean area is presently governed by the relative movements between the Eurasia and Africa plates. The complex interaction of the Africa-Adria and the Anatolian-Aegean-Balkan domains has led the Adria microplate to migrate NW-ward and to collide against Eurasia along the Eastern Southern Alps. As a consequence Adria is presently moving with a general left-lateral displacement with respect to the Apennine mountain belt. The sinistral component of active deformations is also supported by analysis of earthquake focal mechanisms. A comparison between geophysical and geological evidence outlines an apparent discrepancy: most recognized recent and active faults display a remarkable extensional character, as shown by the geometry of continental basin-bounding structutes, whereas geodetic and seismologic evidence indicates the persistency of an active strike-slip, left-lateral dominated

  7. Freeing the Serial Mechanism Designer from Inverse Kinematic Solvability Constraints

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    Diana C. W. Friedman

    2010-01-01

    Full Text Available This paper presents a fast numerical solution for the inverse kinematics of a serial manipulator. The method is implemented on the C-arm, a manipulator designed for use in robotic surgery. The inverse kinematics solution provides all possible solutions for any six degree-of-freedom serial manipulator, assuming that the forward kinematics are known and that it is possible to solve for the remaining joint angles if one joint angle’s value is known. With a fast numerical method and the current levels of computing power, designing a manipulator with closed-form inverse kinematics is no longer necessary. When designing the C-arm, we therefore chose to weigh other factors, such as actuator size and patient safety, more heavily than the ability to find a closed-form inverse kinematics solution.

  8. Online Minimum-acceleration Tra jectory Planning with the Kinematic Constraints

    Institute of Scientific and Technical Information of China (English)

    WANG Ying-Shi; SUN Lei; ZHOU Lu; LIU Jing-Tai

    2014-01-01

    A novel approach based on a type of simplified motion planning (SMP) is presented in this paper to generate online trajectory for manipulator systems with multiple degrees of freedom (DOFs). The key issue is to find minimum-acceleration trajectory planning (MATP) to optimize the arm motion to reduce disturbance. Moreover, necessary and sufficient conditions for solution0s existence subject to all the kinematic constraints of joint position, velocity, acceleration and jerk are devised. Besides, this new method can be activated online from the arbitrary initial state to the arbitrary target state so that it enables the robot to change the original path at any time. Finally, the approach is applied to a real humanoid robot arm with seven DOFs to show its efficiency.

  9. Impact mitigation using kinematic constraints and the full space parameterization method

    Energy Technology Data Exchange (ETDEWEB)

    Morgansen, K.A.; Pin, F.G.

    1996-02-01

    A new method for mitigating unexpected impact of a redundant manipulator with an object in its environment is presented. Kinematic constraints are utilized with the recently developed method known as Full Space Parameterization (FSP). System performance criterion and constraints are changed at impact to return the end effector to the point of impact and halt the arm. Since large joint accelerations could occur as the manipulator is halted, joint acceleration bounds are imposed to simulate physical actuator limitations. Simulation results are presented for the case of a simple redundant planar manipulator.

  10. On kinematical constraints in the hadrogenesis conjecture for the baryon resonance spectrum

    Energy Technology Data Exchange (ETDEWEB)

    Heo, Yonggoo; Lutz, Matthias F.M. [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, Darmstadt (Germany)

    2014-08-15

    We consider the reaction dynamics of bosons with negative parity and spin 0 or 1 and fermions with positive parity and spin (1)/(2) or (3)/(2). Such systems are of central importance for the computation of the baryon resonance spectrum in the hadrogenesis conjecture. Based on a chiral Lagrangian the coupled-channel partial-wave scattering amplitudes have to be computed. We study the generic properties of such amplitudes. A decomposition of the various scattering amplitudes into suitable sets of invariant functions expected to satisfy Mandelstam's dispersion-integral representation is presented. Sets are identified that are free from kinematical constraints and that can be computed efficiently in terms of a novel projection algebra. From such a representation one can deduce the analytic structure of the partial-wave amplitudes. The helicity and the conventional angular-momentum partial-wave amplitudes are kinematically constrained at the Kibble conditions. Therefore an application of a dispersion-integral representation is prohibitively cumbersome. We derive covariant partial-wave amplitudes that are free from kinematical constraints at the Kibble conditions. They correspond to specific polynomials in the 4-momenta and Dirac matrices that solve the various Bethe-Salpeter equations in the presence of short-range interactions analytically. (orig.)

  11. On kinematical constraints in the hadrogenesis conjecture for the baryon resonance spectrum

    Science.gov (United States)

    Heo, Yonggoo; Lutz, Matthias F. M.

    2014-08-01

    We consider the reaction dynamics of bosons with negative parity and spin 0 or 1 and fermions with positive parity and spin or . Such systems are of central importance for the computation of the baryon resonance spectrum in the hadrogenesis conjecture. Based on a chiral Lagrangian the coupled-channel partial-wave scattering amplitudes have to be computed. We study the generic properties of such amplitudes. A decomposition of the various scattering amplitudes into suitable sets of invariant functions expected to satisfy Mandelstam's dispersion-integral representation is presented. Sets are identified that are free from kinematical constraints and that can be computed efficiently in terms of a novel projection algebra. From such a representation one can deduce the analytic structure of the partial-wave amplitudes. The helicity and the conventional angular-momentum partial-wave amplitudes are kinematically constrained at the Kibble conditions. Therefore an application of a dispersion-integral representation is prohibitively cumbersome. We derive covariant partial-wave amplitudes that are free from kinematical constraints at the Kibble conditions. They correspond to specific polynomials in the 4-momenta and Dirac matrices that solve the various Bethe-Salpeter equations in the presence of short-range interactions analytically.

  12. On kinematical constraints in the hadrogenesis conjecture for the baryon resonance spectrum

    CERN Document Server

    Heo, Yonggoo

    2014-01-01

    We consider the reaction dynamics of bosons with negative parity and spin $0$ or $1$ and fermions with positive parity and spin $\\frac{1}{2}$ or $\\frac{3}{2}$. Such systems are of central importance for the computation of the baryon resonance spectrum in the hadrogenesis conjecture. Based on a chiral Lagrangian the coupled-channel partial-wave scattering amplitudes have to be computed. We study the generic properties of such amplitudes. A decomposition of the various scattering amplitudes into suitable sets of invariant functions expected to satisfy Mandelstam's dispersion-integral representation is presented. Sets are identified that are free from kinematical constraints and that can be computed efficiently in terms of a novel projection algebra. From such a representation one can deduce the analytic structure of the partial-wave amplitudes. The helicity and the conventional angular-momentum partial-wave amplitudes are kinematically constrained at the Kibble conditions. Therefore an application of a dispersi...

  13. Constraint Study for a Hand Exoskeleton: Human Hand Kinematics and Dynamics

    Directory of Open Access Journals (Sweden)

    Fai Chen Chen

    2013-01-01

    Full Text Available In the last few years, the number of projects studying the human hand from the robotic point of view has increased rapidly, due to the growing interest in academic and industrial applications. Nevertheless, the complexity of the human hand given its large number of degrees of freedom (DoF within a significantly reduced space requires an exhaustive analysis, before proposing any applications. The aim of this paper is to provide a complete summary of the kinematic and dynamic characteristics of the human hand as a preliminary step towards the development of hand devices such as prosthetic/robotic hands and exoskeletons imitating the human hand shape and functionality. A collection of data and constraints relevant to hand movements is presented, and the direct and inverse kinematics are solved for all the fingers as well as the dynamics; anthropometric data and dynamics equations allow performing simulations to understand the behavior of the finger.

  14. Monte Carlo comparisons of the top quark mass measurement techniques using kinematic constraints

    Science.gov (United States)

    Ryu, Geonmo; Kim, Ji Hyun; Lee, Jason Sang Hun; Park, Inkyu

    2016-12-01

    A Monte Carlo study to compare the sensitivities of the top-quark mass-reconstruction methods using the b-quark decay as a kinematic constraint was performed. The top quark is reconstructed from its decay products, the W boson and the b-quark, and its mass can be obtained by using the 4-vector sum of their final states. However, missing neutrinos and the poor jet energy resolution makes the mass measurement biased and imprecise, always requiring further calibration, and dominates the systematic uncertainties. Several new ideas to increase the mass resolution by using the kinematic constraints of the b quark decays using a charm quark meson were suggested and performed to overcome such systematic limits. In this study, we compare three methods, one using J/ ψ, another using D 0, and the other using D* meson, by extracting their sensitivities to the top-quark mass, as well as their statistical advantages. This study is intended to set a priority in the real data analyses using a new data set from abundant tbar t production in the Large Hadron Collider (LHC) Run 2.

  15. A Smooth Tour Construction Approach for a Mobile Robot with Kinematic Constraints

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    Ahmet Yazici

    2013-10-01

    Full Text Available Mobile robots are increasingly used for service-like applications in which the service points are known and the mobile robot starts from a starting location, visits all the service points requested and returns to the starting location. The tour construction problem in these applications can be treated as a Travelling Salesman Problem (TSP. Classical tour construction algorithms that are proposed for the TSP find tours do not consider robot kinematic constraints. These tours may have sharp turns at some service points. When a mobile robot follows such a tour, it stops, turns and speeds up again. Therefore, the robots waste a considerable amount of power and time. In these cases, tour smoothing can be used to overcome this problem. However, smoothing an existing tour may result in unnecessarily long tours. In this study, a Smooth Tour Construction (STC approach is proposed for mobile robots with kinematic constraints. The STC approach considers tour construction and tour smoothing concurrently. The logic behind the tour construction part of the approach is based on the Savings Algorithm (SA. The tour smoothing is based on Dubins’ arc-line approach. Experiments are conducted for P3-DX robots in a laboratory environment. Comparisons are also drawn with various tour smoothing algorithms in simulation environments to demonstrate the effectiveness of the proposed STC approach.

  16. Sampling-based exploration of folded state of a protein under kinematic and geometric constraints

    KAUST Repository

    Yao, Peggy

    2011-10-04

    Flexibility is critical for a folded protein to bind to other molecules (ligands) and achieve its functions. The conformational selection theory suggests that a folded protein deforms continuously and its ligand selects the most favorable conformations to bind to. Therefore, one of the best options to study protein-ligand binding is to sample conformations broadly distributed over the protein-folded state. This article presents a new sampler, called kino-geometric sampler (KGS). This sampler encodes dominant energy terms implicitly by simple kinematic and geometric constraints. Two key technical contributions of KGS are (1) a robotics-inspired Jacobian-based method to simultaneously deform a large number of interdependent kinematic cycles without any significant break-up of the closure constraints, and (2) a diffusive strategy to generate conformation distributions that diffuse quickly throughout the protein folded state. Experiments on four very different test proteins demonstrate that KGS can efficiently compute distributions containing conformations close to target (e.g., functional) conformations. These targets are not given to KGS, hence are not used to bias the sampling process. In particular, for a lysine-binding protein, KGS was able to sample conformations in both the intermediate and functional states without the ligand, while previous work using molecular dynamics simulation had required the ligand to be taken into account in the potential function. Overall, KGS demonstrates that kino-geometric constraints characterize the folded subset of a protein conformation space and that this subset is small enough to be approximated by a relatively small distribution of conformations. © 2011 Wiley Periodicals, Inc.

  17. Human-robot interaction: kinematics and muscle activity inside a powered compliant knee exoskeleton.

    Science.gov (United States)

    Knaepen, Kristel; Beyl, Pieter; Duerinck, Saartje; Hagman, Friso; Lefeber, Dirk; Meeusen, Romain

    2014-11-01

    Until today it is not entirely clear how humans interact with automated gait rehabilitation devices and how we can, based on that interaction, maximize the effectiveness of these exoskeletons. The goal of this study was to gain knowledge on the human-robot interaction, in terms of kinematics and muscle activity, between a healthy human motor system and a powered knee exoskeleton (i.e., KNEXO). Therefore, temporal and spatial gait parameters, human joint kinematics, exoskeleton kinetics and muscle activity during four different walking trials in 10 healthy male subjects were studied. Healthy subjects can walk with KNEXO in patient-in-charge mode with some slight constraints in kinematics and muscle activity primarily due to inertia of the device. Yet, during robot-in-charge walking the muscular constraints are reversed by adding positive power to the leg swing, compensating in part this inertia. Next to that, KNEXO accurately records and replays the right knee kinematics meaning that subject-specific trajectories can be implemented as a target trajectory during assisted walking. No significant differences in the human response to the interaction with KNEXO in low and high compliant assistance could be pointed out. This is in contradiction with our hypothesis that muscle activity would decrease with increasing assistance. It seems that the differences between the parameter settings of low and high compliant control might not be sufficient to observe clear effects in healthy subjects. Moreover, we should take into account that KNEXO is a unilateral, 1 degree-of-freedom device.

  18. The overmassive black hole in NGC 1277: new constraints from molecular gas kinematics

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    Scharwächter, J.; Combes, F.; Salomé, P.; Sun, M.; Krips, M.

    2016-04-01

    We report the detection of CO(1-0) emission from NGC 1277, a lenticular galaxy in the Perseus Cluster. NGC 1277 has previously been proposed to host an overmassive black hole (BH) compared to the galaxy bulge luminosity (mass), based on stellar-kinematic measurements. The CO(1-0) emission, observed with the IRAM Plateau de Bure Interferometer (PdBI) using both, a more compact (2.9-arcsec resolution) and a more extended (1-arcsec resolution) configuration, is likely to originate from the dust lane encompassing the galaxy nucleus at a distance of 0.9 arcsec (˜320 pc). The double-horned CO(1-0) profile found at 2.9-arcsec resolution traces 1.5 × 108 M⊙ of molecular gas, likely orbiting in the dust lane at ˜550 km s-1, which suggests a total enclosed mass of ˜2 × 1010 M⊙. At 1-arcsec resolution, the CO(1-0) emission appears spatially resolved along the dust lane in east-west direction, though at a low signal-to-noise ratio. In agreement with the previous stellar-kinematic measurements, the CO(1-0) kinematics is found to be consistent with an ˜1.7 × 1010 M⊙ BH for a stellar mass-to-light ratio of M/LV = 6.3, while a less massive BH of ˜5 × 109 M⊙ is possible when assuming a larger M/LV = 10. While the molecular gas reservoir may be associated with a low level of star formation activity, the extended 2.6-mm continuum emission is likely to originate from a weak AGN, possibly characterized by an inverted radio-to-millimetre spectral energy distribution. Literature radio and X-ray data indicate that the BH in NGC 1277 is also overmassive with respect to the Fundamental Plane of BH activity.

  19. Effects of load on good morning kinematics and EMG activity.

    Science.gov (United States)

    Vigotsky, Andrew David; Harper, Erin Nicole; Ryan, David Russell; Contreras, Bret

    2015-01-01

    Many strength and conditioning coaches utilize the good morning (GM) to strengthen the hamstrings and spinal erectors. However, little research exists on its electromyography (EMG) activity and kinematics, and how these variables change as a function of load. The purpose of this investigation was to examine how estimated hamstring length, integrated EMG (IEMG) activity of the hamstrings and spinal erectors, and kinematics of the lumbar spine, hip, knee, and ankle are affected by changes in load. Fifteen trained male participants (age = 24.6 ± 5.3 years; body mass = 84.7 ± 11.3 kg; height = 180.9 ± 6.8 cm) were recruited for this study. Participants performed five sets of the GM, utilizing 50, 60, 70, 80, and 90% of one-repetition maximum (1RM) in a randomized fashion. IEMG activity of hamstrings and spinal erectors tended to increase with load. Knee flexion increased with load on all trials. Estimated hamstring length decreased with load. However, lumbar flexion, hip flexion, and plantar flexion experienced no remarkable changes between trials. These data provide insight as to how changing the load of the GM affects EMG activity, kinematic variables, and estimated hamstring length. Implications for hamstring injury prevention are discussed. More research is needed for further insight as to how load affects EMG activity and kinematics of other exercises.

  20. Effects of load on good morning kinematics and EMG activity

    Directory of Open Access Journals (Sweden)

    Andrew David Vigotsky

    2015-01-01

    Full Text Available Many strength and conditioning coaches utilize the good morning (GM to strengthen the hamstrings and spinal erectors. However, little research exists on its electromyography (EMG activity and kinematics, and how these variables change as a function of load. The purpose of this investigation was to examine how estimated hamstring length, integrated EMG (IEMG activity of the hamstrings and spinal erectors, and kinematics of the lumbar spine, hip, knee, and ankle are affected by changes in load. Fifteen trained male participants (age = 24.6 ± 5.3 years; body mass = 84.7 ± 11.3 kg; height = 180.9 ± 6.8 cm were recruited for this study. Participants performed five sets of the GM, utilizing 50, 60, 70, 80, and 90% of one-repetition maximum (1RM in a randomized fashion. IEMG activity of hamstrings and spinal erectors tended to increase with load. Knee flexion increased with load on all trials. Estimated hamstring length decreased with load. However, lumbar flexion, hip flexion, and plantar flexion experienced no remarkable changes between trials. These data provide insight as to how changing the load of the GM affects EMG activity, kinematic variables, and estimated hamstring length. Implications for hamstring injury prevention are discussed. More research is needed for further insight as to how load affects EMG activity and kinematics of other exercises.

  1. Patterns of thermal constraint on ectotherm activity.

    Science.gov (United States)

    Gunderson, Alex R; Leal, Manuel

    2015-05-01

    Thermal activity constraints play a major role in many aspects of ectotherm ecology, including vulnerability to climate change. Therefore, there is strong interest in developing general models of the temperature dependence of activity. Several models have been put forth (explicitly or implicitly) to describe such constraints; nonetheless, tests of the predictive abilities of these models are lacking. In addition, most models consider activity as a threshold trait instead of considering continuous changes in the vigor of activity among individuals. Using field data for a tropical lizard (Anolis cristatellus) and simulations parameterized by our observations, we determine how well various threshold and continuous-activity models match observed activity patterns. No models accurately predicted activity under all of the thermal conditions that we considered. In addition, simulations showed that the performance of threshold models decreased as temperatures increased, which is a troubling finding given the threat of global climate change. We also find that activity rates are more sensitive to temperature than are the physiological traits often used as a proxy for fitness. We present a model of thermal constraint on activity that integrates aspects of both the threshold model and the continuous-activity model, the general features of which are supported by activity data from other species. Overall, our results demonstrate that greater attention should be given to fine-scale patterns of thermal constraint on activity.

  2. Geotectonic Elements, Stuctural Constraints and Current Problems for a Kinematic Reconstruction of the Caribbean Plate Margins during the Cretaceous.

    Science.gov (United States)

    Giunta, G.

    2001-12-01

    blocks; (2) the sinking direction of the previously subducted oceanic slabs; (3) the locations of and relationships between the intraoceanic and sub-continental subduction zones. Taking this points into account and on the basis of the new geological constraints, some alternative tectonic models can be elaborated, each of which needs kinematic releases (strike-slip faults) allowing either the simultaneous activation of intraoceanic and sub-continental collisions, or the progressive insertion by tectonic erosion of the rifted continental portions in the subduction complexes. In a whole transpressional regime the different subduction zones can be inferred to dip either eastward with a later flip westward below the oceanic plateau, or continuously westward; this last case is a better fit for the Northern margin than the Southern margin of the Caribbean plate, where a much more complicated kinematic mechanism should be envisaged. * Researches carried-out in the framework of the IGCP 433 "Caribbean Plate Tectonics".

  3. Institutional Constraints, Legislative Activism and Policy Change

    DEFF Research Database (Denmark)

    Citi, Manuele; Justesen, Mogens Kamp

    2016-01-01

    This article presents a study of how institutional constraints affect legislative activism and how legislative activism in turn affects policy change through an analysis of the European Union's legislative process. The argument revolves around the key role of the European Commission in advancing ...

  4. Effects of constraint-induced therapy combined with eye patching on functional outcomes and movement kinematics in poststroke neglect.

    Science.gov (United States)

    Wu, Ching-Yi; Wang, Tien-Ni; Chen, Yu-Ting; Lin, Keh-Chung; Chen, Yi-An; Li, Hsiang-Ting; Tsai, Pei-Luen

    2013-01-01

    OBJECTIVE. We investigated the effect of constraint-induced therapy (CIT) plus eye patching (EP), CIT alone, and conventional treatment on functional performance, eye movement, and trunk-arm kinematics in stroke patients with neglect syndrome. METHOD. Twenty-four participants were recruited and randomly allocated to three intervention groups. All participants received intervention 2 hr/day, 5 days/wk, for 3 wk. Outcome measures included the Catherine Bergego Scale, eye movement, and trunk-arm kinematic analysis. RESULTS. The CIT + EP and CIT groups demonstrated larger improvements in functional performance than the control group. The CIT group showed better performance with left fixation points than the CIT+EP group and shorter reaction time than the control group. The CIT + EP group improved more in preplanned control and leftward trunk shift than the other two groups. CONCLUSION. CIT + EP and CIT were more effective interventions than conventional treatment of patients with neglect syndrome in daily functional performance.

  5. Kinematics Card Sort Activity: Insight into Students' Thinking

    Science.gov (United States)

    Berryhill, Erin; Herrington, Deborah; Oliver, Keith

    2016-12-01

    Kinematics is a topic students are unknowingly aware of well before entering the physics classroom. Students observe motion on a daily basis. They are constantly interpreting and making sense of their observations, unintentionally building their own understanding of kinematics before receiving any formal instruction. Unfortunately, when students take their prior conceptions to understand a new situation, they often do so in a way that inaccurately connects their learning. We were motivated to identify strategies to help our students make accurate connections to their prior knowledge and understand kinematics at a deeper level. To do this, we integrated a formative assessment card sort into a kinematic graphing unit within an introductory high school physics course. Throughout the activities, we required students to document and reflect upon their thinking. This allowed their learning to build upon their own previously held conceptual understanding, which provided an avenue for cognitive growth. By taking a more direct approach to eliciting student reasoning, we hoped to improve student learning and guide our assessment of their learning.

  6. The over-massive black hole in NGC 1277: New constraints from molecular gas kinematics

    CERN Document Server

    Scharwächter, J; Salomé, P; Sun, M; Krips, M

    2015-01-01

    We report the detection of CO(1-0) emission from NGC 1277, a lenticular galaxy in the Perseus Cluster, which has been proposed to host a $(1.3-1.7) \\times 10^{10}\\ M_\\odot$ black hole (BH) based on stellar kinematic measurements. The CO(1-0) emission, observed with the IRAM Plateau de Bure Interferometer (PdBI) using both, a more extended (~1-arcsec resolution) and a more compact (~2.5-arcsec resolution) configuration, is likely to originate from the dust lane encompassing the galaxy nucleus at a distance of 0.9 arcsec (~320 pc). The spatially-unresolved double-horned CO(1-0) profile found at 2.5-arcsec resolution is likely to trace gas orbiting in the dust lane with rotational velocities of ~520 km s$^{-1}$, indicative of an enclosed mass of ~$2 \\times 10^{10}\\ M_\\odot$. Based on models with realistic mass distributions, the CO(1-0) kinematics is found to be consistent with a ~$1.7 \\times 10^{10}\\ M_\\odot$ BH, while a less massive BH is still possible assuming a large stellar mass-to-light ratio. The stronge...

  7. Kinematic and Chemical constraints on the formation of M31's inner and outer halo

    CERN Document Server

    Koch, A; Reitzel, D; Martin, N F; Ibata, R A; Chapman, S C; Majewski, S R; Mori, M; Loh, Y -S; Ostheimer, J C

    2007-01-01

    The halo of M31 shows a wealth of substructures that are consistent with satellite accretion. Here we report on kinematic and abundance results from Keck/DEIMOS spectroscopy in the calcium triplet region of over 3500 red giant star candidates along the minor axis and in off-axis spheroid fields of M31. Our data reach out to large radial distances of 160 kpc. The derived velocity distributions show a kinematically cold substructure at 17 kpc that has been reported before. We devise an improved method to measure accurate metallicities from the calcium triplet in low signal-to-noise spectra using a coaddition of the individual lines. The resulting distribution leads us to note an even stronger gradient in the abundance distribution along M31's minor axis than previously detected. The mean metallicity in the outer halo reaches below -2 dex, with individual values as low as -2.6 dex. In the inner spheroid, at 17-19 kpc, we find a sharp decline of ~0.5 dex in metallicity, which roughly coincides with the edge of an...

  8. High-Redshift Galaxy Kinematics: Constraints on Models of Disk Formation

    CERN Document Server

    Robertson, Brant E

    2008-01-01

    Integral field spectroscopy of galaxies at redshift z~2 has revealed a population of early-forming, rotationally-supported disks. These high-redshift systems provide a potentially important clue to the formation processes that build disk galaxies in the universe. A particularly well-studied example is the z=2.38 galaxy BzK-15504, which was shown by Genzel et al. (2006) to be a rotationally supported disk despite the fact that its high star formation rate and short gas consumption timescale require a very rapid acquisition of mass. Previous kinematical analyses have suggested that z~2 disk galaxies like BzK-15504 did not form through mergers because their line-of-sight velocity fields display low levels of asymmetry. We perform the same kinematical analysis on a set of simulated disk galaxies formed in gas-rich mergers of the type that may be common at high redshift, and show that the remnant disks display low velocity field asymmetry and satisfy the criteria that have been used to classify high-redshift galax...

  9. OPTIMASS: A Package for the Minimization of Kinematic Mass Functions with Constraints

    CERN Document Server

    Cho, Won Sang; Kim, Doojin; Lim, Sung Hak; Matchev, Konstantin T; Moortgat, Filip; Pape, Luc; Park, Myeonghun

    2015-01-01

    Reconstructed mass variables, such as $M_2$, $M_{2C}$, $M_T^\\star$, and $M_{T2}^W$, play an essential role in searches for new physics at hadron colliders. The calculation of these variables generally involves constrained minimization in a large parameter space, which is numerically challenging. We provide a C++ code, OPTIMASS, which interfaces with the MINUIT library to perform this constrained minimization using the Augmented Lagrangian Method. The code can be applied to arbitrarily general event topologies and thus allows the user to significantly extend the existing set of kinematic variables. We describe this code and its motivation and demonstrate its use in the analysis of the fully leptonic decay of pair-produced top quarks using the $M_2$ variables.

  10. Geologic constraints on kinematic models and age of formation of the Amerasia Basin of the Arctic

    Science.gov (United States)

    Miller, E. L.

    2015-12-01

    A wealth of new geologic and geophysical data now exist for the Amerasia Basin, but the details of its age and the nature/kinematics of events that resulted in its formation remain elusive. Basement rock ages, detrital zircon signatures of sedimentary rocks, and sediment dispersal systems have been used to show how parts of the southern margin(s) of the Amerasia Basin (Arctic Alaska-Chukotka, AAC) match their rifted margin counterparts on the Eurasia and Canada side of the Amerasia Basin. Thus we know the approximate finite translations needed to restore the paleogeography of the Arctic, but not the kinematics involved. Important features of the Amerasia Basin that need to be explained in a model for its opening are the age and extent of the high Arctic LIP, the linearity of the strip of continental crust represented by the Lomonosov Ridge, its right angle intersection with the Canadian Arctic margin, and the directional fault patterns mapped bathymetrically and seismically across the Alpha-Lomonosov Ridge and surrounding seafloor. Across AAC, post-Early Cretaceous oroclinal bends provide insight into strike-slip components of deformation involved in opening of the Amerasia Basin: The Chukchi syntax offsets the Brooks Range in a right-lateral sense from Wrangel Island along the Herald Arch; right-lateral motion of Arctic Alaska with respect to the Chukchi Borderland during opening of the Canada Basin; right-lateral shear in Chukotka during 100 Ma magmatism; the tight bend in the northern Verkhoyansk, result of Cretaceous right-lateral shear. The land-based relationships imply a post-Early Cretaceous, younger than Barremian (~130 Ma) age for onset of magmatism and extension related to rifting and formation of the Amerasia Basin. At least two stages of extension are documented, with older E-W extension characterizing the longitude of the New Siberian Islands to Pevek, Russian Arctic, (ca.125 Ma to 100 Ma), with younger N-S extension superimposed on this system (ca

  11. The APOSTLE project: Local Group kinematic mass constraints and simulation candidate selection

    CERN Document Server

    Fattahi, Azadeh; Sawala, Till; Frenk, Carlos S; Oman, Kyle A; Crain, Robert A; Furlong, Michelle; Schaller, Matthieu; Schaye, Joop; Theuns, Tom; Jenkins, Adrian

    2015-01-01

    We use a large sample of isolated dark matter halo pairs drawn from cosmological N-body simulations to identify candidate systems whose kinematics match that of the Local Group of Galaxies (LG). We find, in agreement with the "timing argument" and earlier work, that the separation and approach velocity of the Milky Way (MW) and Andromeda (M31) galaxies favour a total mass for the pair of ~ 5*10^12 M_sun. A mass this large, however, is difficult to reconcile with the small relative tangential velocity of the pair, as well as with the small deceleration from the Hubble flow observed for the most distant LG members. Halo pairs that match these three criteria have average masses a factor of ~2 times smaller than suggested by the timing argument, but with large dispersion, spanning more than a decade in mass. Guided by these results, we have selected 12 halo pairs with total mass in the range 1.6-3.6 *10^12 M_sun for the APOSTLE project (A Project Of Simulations of The Local Environment), a suite of resimulations ...

  12. Kinematic constraints on buckling a lithospheric-scale orocline during Pangea assembly: a geologic synthesis

    Science.gov (United States)

    Weil, Arlo; Gutiérrez-Alonso, Gabriel; Johnston, Stephen; Pastor Galán, Daniel

    2013-04-01

    The Paleozoic Variscan orogeny was a large-scale collisional event involving amalgamation of multiple continents and micro-continents. Existing data, suggests oroclinal buckling of an originally near-linear convergent margin during the last stages of Variscan deformation in the late Paleozoic. Closure of the Rheic Ocean resulted in E-W shortening (present-day coordinates) in the Carboniferous, producing a near linear N-S trending, east-verging belt. Subsequent N-S shortening near the Carb-Permian boundary resulted in oroclinal buckling. This late-stage orogenic event remains an enigmatic part of final Pangea amalgamation. The present-day arc curvature of the Variscan has inspired many tectonic models, with little agreement between them. While there is general consensus that two separate phases of deformation occurred, various models consider that curvature was caused by: dextral transpression around a Gondwana indentor; strike-slip wrench tectonics; or a change in tectonic transport direction due to changing stress fields. More recent models explain the curvature as an orocline, with potentially two opposite-facing bends, caused by secondary rotations. Deciphering the kinematic history of curved orogens is difficult, and requires establishment of two deformation phases: an initial compressive phase that forms a relatively linear belt, and a second phase that causes vertical-axis rotation of the orogenic limbs. Historically the most robust technique to accurately quantify vertical axis-rotation in curved orogens is paleomagnetic analysis, but recently other types of data, including fracture, geochemical, petrologic, paleo-current and calcite twin data, have been used to corroborate secondary buckling. A review of existing and new Variscan data from Iberia is presented that argues for secondary buckling of an originally linear orogenic system. Together, these data constrain oroclinal buckling of the Cantabrian Orocline to have occurred in about 10 Ma during the

  13. A Four-Dimensional {\\Lambda}CDM-Type Cosmological Model Induced from Higher Dimensions Using a Kinematical Constraint

    CERN Document Server

    Akarsu, Ozgur

    2013-01-01

    A class of cosmological solutions of higher dimensional Einstein field equations with the energy-momentum tensor of a homogeneous, isotropic fluid as the source are considered with an anisotropic metric that includes the direct sum of a 3-dimensional (physical, flat) external space metric and an n-dimensional (compact, flat) internal space metric. A simple kinematical constraint is postulated that correlates the expansion rates of the external and internal spaces in terms of a real parameter \\lambda. A specific solution for which both the external and internal spaces expand at different rates is given analytically for n=3. Assuming that the internal dimensions were at Planck length scales at the beginning t=0, the external space starts with a Big Bang and the external and internal spaces both reach the same size after 10^{-176} Gyr. Then during the lifetime of the observed universe (13.7 Gyr), the external dimensions would expand 10^{59} times while the internal dimensions expand only 1.49 times. The effectiv...

  14. Progressive migration of slab break-off along the southern Tyrrhenian plate boundary: Constraints for the present day kinematics

    Science.gov (United States)

    Chiarabba, Claudio; Palano, Mimmo

    2017-04-01

    The Ionian subduction in the central Mediterranean, just 200 km wide, is one of the narrowest in the world. Its evolution has involved a progressive disruption of the subducting slab, contemporaneous to the retreat and step-wise opening of back-arc basins. In this study, we analyse velocity anomalies of the upper mantle, together with the most comprehensive set of earthquake locations and kinematic indicators available for Italy, to reconstruct the geodynamics and tectonic evolution of the Ionian subduction system. Along the Sicilian boundary, we identify an eastward migration of the slab edge with detachment of the Ionian oceanic lithosphere. We hypothesize that the progressive detachment of the slab took place along lithospheric transform faults of the Neo-Tethys Ocean. Among the main active kinematic elements of the Ionian accretionary wedge, we suggest that a ∼400-km-long and highly segmented shear zone formed by the Aeolian-Tindari-Letojanni fault system and the Ionian fault represents the surface expression of such a lithospheric tearing. The present day convergence between the Eurasian and African plates is accommodated both at the frontal thrust of the flexed Hyblean margin in southern Sicily and offshore along the Tyrrhenian Sea. Lithospheric bending favors the wedging of the mantle underneath northern Sicily, while magmatic fluids are channeled along slab tears.

  15. Effects of Stroke on Ipsilesional End-Effector Kinematics in a Multi-Step Activity of Daily Living

    Science.gov (United States)

    Gulde, Philipp; Hughes, Charmayne Mary Lee; Hermsdörfer, Joachim

    2017-01-01

    Background: Stroke frequently impairs activities of daily living (ADL) and deteriorates the function of the contra- as well as the ipsilesional limbs. In order to analyze alterations of higher motor control unaffected by paresis or sensory loss, the kinematics of ipsilesional upper limb movements in patients with stroke has previously been analyzed during prehensile movements and simple tool use actions. By contrast, motion recording of multi-step ADL is rare and patient-control comparisons for movement kinematics are largely lacking. Especially in clinical research, objective quantification of complex externally valid tasks can improve the assessment of neurological impairments. Methods: In this preliminary study we employed three-dimensional motion recording and applied kinematic analysis in a multi-step ADL (tea-making). The trials were examined with respect to errors and sub-action structure, durations, path lengths (PLs), peak velocities, relative activity (RA) and smoothness. In order to check for specific burdens the sub-actions of the task were extracted and compared. To examine the feasibility of the approach, we determined the behavioral and kinematic metrics of the (ipsilesional) unimanual performance of seven chronic stroke patients (64a ± 11a, 3 with right/4 with left brain damage (LBD), 2 with signs of apraxia, variable severity of paresis) and compared the results with data of 14 neurologically healthy age-matched control participants (70a ± 7a). Results: T-tests revealed that while the quantity and structure of sub-actions of the task were similar. The analysis of end-effector kinematics was able to detect clear group differences in the associated parameters. Specifically, trial duration (TD) was increased (Cohen’s d = 1.77); the RA (Cohen’s d = 1.72) and the parameters of peak velocities (Cohen’s d = 1.49/1.97) were decreased in the patient group. Analysis of the task’s sub-actions repeated measures analysis of variance (rmANOVA) revealed

  16. Upper Extremity Kinematics and Muscle Activation Patterns in Subjects With Facioscapulohumeral Dystrophy

    NARCIS (Netherlands)

    Bergsma, Arjen; Murgia, Alessio; Cup, Edith H.; Verstegen, Paul P.; Meijer, Kenneth; de Groot, Imelda J.

    2014-01-01

    Objective: To compare the kinematics and muscle activity of subjects with facioscapulohumeral dystrophy (FSHD) and healthy control subjects during the performance of standardized upper extremity tasks. Design: Exploratory case-control study. Setting: A movement laboratory. Participants: Subjects (N=

  17. The use of smartphones to teach kinematics: an inexpensive activity

    Science.gov (United States)

    André Testoni, Leonardo; Brockington, Guilherme

    2016-11-01

    This frontline seeks to reinterpret a classic kinematic experiment that aims to mark the position and temporal instants of a fictional mobile object in a uniform motion, creating a table based on position × time and a linear graphic format. Generally, this approach requires sophisticated experimental apparatus (such as air mattresses or rails) that may limit its ability to be reproduced due to cost and thus jeopardising the exercise. Therefore, we suggest that this experiment be performed with real mobile objects to be able to observe the difficulty in controlling the kinematic variables that produce a ‘perfectly’ uniform movement. This object can be the student, playing a uniform motion walking on a trajectory with markings of 5 m in 5 m amounting to a total displacement of 30 m. Additionally, acceleration data is collected during the journey via a smartphone accelerometer, allowing for more in-depth discussions of these essential concepts for the study of bodies in motion.

  18. Kinematic evidence for superbubbles in I Zw 18 constraints on the star formation history and chemical evolution

    CERN Document Server

    Martin, L

    1996-01-01

    We have combined measurements of the kinematics, morphology, and oxygen abundance of the ionized gas in \\IZw18, one of the most metal-poor galaxies known, to examine the star formation history and chemical mixing processes.

  19. Phonotactic Constraints Are Activated across Languages in Bilinguals

    Science.gov (United States)

    Freeman, Max R.; Blumenfeld, Henrike K.; Marian, Viorica

    2016-01-01

    During spoken language comprehension, auditory input activates a bilingual’s two languages in parallel based on phonological representations that are shared across languages. However, it is unclear whether bilinguals access phonotactic constraints from the non-target language during target language processing. For example, in Spanish, words with s+ consonant onsets cannot exist, and phonotactic constraints call for epenthesis (addition of a vowel, e.g., stable/estable). Native Spanish speakers may produce English words such as estudy (“study”) with epenthesis, suggesting that these bilinguals apply Spanish phonotactic constraints when speaking English. The present study is the first to examine whether bilinguals access Spanish phonotactic constraints during English comprehension. In an English cross-modal priming lexical decision task, Spanish–English bilinguals and English monolinguals heard English cognate and non-cognate primes containing s+ consonant onsets or controls without s+ onsets, followed by a lexical decision on visual targets with the /e/ phonotactic constraint or controls without /e/. Results revealed that bilinguals were faster to respond to /es/ non-word targets preceded by s+ cognate primes and /es/ and /e/ non-word targets preceded by s+ non-cognate primes, confirming that English primes containing s+ onsets activated Spanish phonotactic constraints. These findings are discussed within current accounts of parallel activation of two languages during bilingual spoken language comprehension, which may be expanded to include activation of phonotactic constraints from the irrelevant language. PMID:27242615

  20. The SAMI Galaxy Survey: Unveiling the nature of kinematically offset active galactic nuclei

    CERN Document Server

    Allen, J T; Scott, N; Fogarty, L M R; Ho, I -T; Medling, A M; Leslie, S K; Bland-Hawthorn, J; Bryant, J J; Croom, S M; Goodwin, M; Green, A W; Konstantopoulos, I S; Lawrence, J S; Owers, M S; Richards, S N; Sharp, R

    2015-01-01

    We have observed two kinematically offset active galactic nuclei (AGN), whose ionised gas is at a different line-of-sight velocity to their host galaxies, with the SAMI integral field spectrograph (IFS). One of the galaxies shows gas kinematics very different to the stellar kinematics, indicating a recent merger or accretion event. We demonstrate that the star formation associated with this event was triggered within the last 100 Myr. The other galaxy shows simple disc rotation in both gas and stellar kinematics, aligned with each other, but in the central region has signatures of an outflow driven by the AGN. Other than the outflow, neither galaxy shows any discontinuity in the ionised gas kinematics at the galaxy's centre. We conclude that in these two cases there is no direct evidence of the AGN being in a supermassive black hole binary system. Our study demonstrates that selecting kinematically offset AGN from single-fibre spectroscopy provides, by definition, samples of kinematically peculiar objects, bu...

  1. Kinematic active region formation in a three-dimensional solar dynamo model

    CERN Document Server

    Yeates, A R

    2013-01-01

    We propose a phenomenological technique for modelling the emergence of active regions within a three-dimensional, kinematic dynamo framework. By imposing localised velocity perturbations, we create emergent flux-tubes out of toroidal magnetic field at the base of the convection zone, leading to the eruption of active regions at the solar surface. The velocity perturbations are calibrated to reproduce observed active region properties (including the size and flux of active regions, and the distribution of tilt angle with latitude), resulting in a more consistent treatment of flux-tube emergence in kinematic dynamo models than artificial flux deposition. We demonstrate how this technique can be used to assimilate observations and drive a kinematic 3D model, and use it to study the characteristics of active region emergence and decay as a source of poloidal field. We find that the poloidal components are strongest not at the solar surface, but in the middle convection zone, in contrast with the common assumption...

  2. Dynamic active constraints for hyper-redundant flexible robots.

    Science.gov (United States)

    Kwok, Ka-Wai; Mylonas, George P; Sun, Loi Wah; Lerotic, Mirna; Clark, James; Athanasiou, Thanos; Darzi, Ara; Yang, Guang-Zhong

    2009-01-01

    In robot-assisted procedures, the surgeon's ability can be enhanced by navigation guidance through the use of virtual fixtures or active constraints. This paper presents a real-time modeling scheme for dynamic active constraints with fast and simple mesh adaptation under cardiac deformation and changes in anatomic structure. A smooth tubular pathway is constructed which provides assistance for a flexible hyper-redundant robot to circumnavigate the heart with the aim of undertaking bilateral pulmonary vein isolation as part of a modified maze procedure for the treatment of debilitating arrhythmia and atrial fibrillation. In contrast to existing approaches, the method incorporates detailed geometrical constraints with explicit manipulation margins of the forbidden region for an entire articulated surgical instrument, rather than just the end-effector itself. Detailed experimental validation is conducted to demonstrate the speed and accuracy of the instrument navigation with and without the use of the proposed dynamic constraints.

  3. Kinematic Analysis of Four-Link Suspension of Steering Wheel by Means of Equation Sets of Geometrical Constraints with Various Structure

    Science.gov (United States)

    Kowalski, M. S.

    2016-09-01

    In research of the kinematic and dynamic properties of complex mechanical set-ups, results of numerical experiments are used. It is required to minimize the calculation time of various problems in the domain. For the multi-link suspension of the steered wheel, sets of the equations of the geometrical constraints were presented in two structurally different forms, scalar and vector. The vector set consists of the transcendental equations. Their solution was possible after previous expanding the trigonometric functions into power series. Because of the finite amount of the computer memory for the algorithm solving the vector form, it was possible to obtain solutions consisting of three terms. The number of terms in power series of equations' solutions determines the magnitudes of increments of input parameters (degrees of freedom). In this paper it is demonstrated, that fulfilling of this demand is possible by the change of the geometrical constraint's structure of the multi-link wheel suspension system.

  4. Optimizing Computation of Repairs from Active Integrity Constraints

    DEFF Research Database (Denmark)

    Cruz-Filipe, Luís

    2014-01-01

    Active integrity constraints (AICs) are a form of integrity constraints for databases that not only identify inconsistencies, but also suggest how these can be overcome. The semantics for AICs defines different types of repairs, but deciding whether an inconsistent database can be repaired...... and finding possible repairs is a NP- or Σ2p-complete problem, depending on the type of repairs one has in mind. In this paper, we introduce two different relations on AICs: an equivalence relation of independence, allowing the search to be parallelized among the equivalence classes, and a precedence relation...

  5. Muscle activity and kinematics of forefoot and rearfoot strike runners

    Directory of Open Access Journals (Sweden)

    A.N. Ahn

    2014-06-01

    Conclusion: This earlier and longer relative activation of the plantarflexors likely enhances the capacity for the passive structures of the foot and ankle to store elastic energy, and may also enhance the performance of the active muscle by increasing the storage of elastic strain energy in the cross-bridges and activated titin.

  6. Paleomagnetic, structural, and stratigraphic constraints on transverse fault kinematics during basin inversion: The Pamplona Fault (Pyrenees, north Spain)

    Science.gov (United States)

    LarrasoañA, Juan Cruz; ParéS, Josep MaríA.; MilláN, HéCtor; Del Valle, JoaquíN.; Pueyo, Emilio Luis

    2003-12-01

    The Pamplona Fault in the Pyrenees is a major transverse structure that has been classically interpreted as a strike-slip fault. However, lack of consensus concerning the sense of movement casts doubt on its actual kinematics and, as a consequence, its role in the Cenozoic evolution of the Pyrenees remains controversial. In order to assess its kinematics, we have conducted a paleomagnetic, structural, and stratigraphic study focused on the Mesozoic and Tertiary sedimentary rocks that outcrop around the southern segment of the fault. Restoration of balanced cross sections allows us to examine the present-day spatial relationship of the sedimentary sequences on both sides of the fault and to reconstruct the geometry of the extensional basins formed during Mesozoic rifting episodes in the Bay of Biscay and Pyrenean domains. Paleomagnetic results indicate that no significant tectonic rotations occurred around the fault during Tertiary inversion of the Pyrenees. The lack of tectonic rotations and revaluation of previous hypotheses argues against a strike-slip movement of the fault. We propose a new model in which the Pamplona Fault is treated as a large-scale "hanging wall drop" fault whose kinematics was determined by variations in the geometry and thickness of Mesozoic sequences on both sides of the fault. These variations influenced the geometry of the thrust sheet developed during Tertiary compression. We are unaware of any other transverse fault that has been interpreted in this fashion; thus the Pamplona Fault serves as a case study for the evolution of transverse faults involved in basin inversion processes.

  7. Kinematics and Chemistry of Stars Along the Sagittarius Trailing Tidal Tail and Constraints on the Milky Way Mass Distribution

    CERN Document Server

    Carlin, Jeffrey L; Casetti-Dinescu, Dana I; Law, David R; Girard, Terrence M; Patterson, Richard J

    2011-01-01

    We present three-dimensional kinematics of Sagittarius (Sgr) trailing tidal debris in six fields located 70-130 degrees along the stream from the Sgr dwarf galaxy core. The data are from our proper-motion (PM) survey of Kapteyn's Selected Areas, in which we have measured accurate PMs to faint magnitudes in 40x40 arcmin fields evenly spaced across the sky. The radial velocity (RV) signature of Sgr has been identified among our follow-up spectroscopic data in four of the six fields and combined with mean PMs of spectroscopically-confirmed members to derive space motions of Sgr debris based on 15-64 confirmed stream members per field. These kinematics are compared to predictions of the Law & Majewski (2010) model of Sgr disruption; we find reasonable agreement with model predictions in RVs and PMs along Galactic latitude. However, an upward adjustment of the Local Standard of Rest velocity Theta_LSR from its standard 220 km/s to at least $232\\pm14$ km/s (and possibly as high as $264\\pm23$ km/s) is necessary ...

  8. EFFECT OF KAYAK ERGOMETER ELASTIC TENSION ON UPPER LIMB EMG ACTIVITY AND 3D KINEMATICS

    Directory of Open Access Journals (Sweden)

    Neil Fleming

    2012-09-01

    Full Text Available Despite the prevalence of shoulder injury in kayakers, limited published research examining associated upper limb kinematics and recruitment patterns exists. Altered muscle recruitment patterns on-ergometer vs. on-water kayaking were recently reported, however, mechanisms underlying changes remain to be elucidated. The current study assessed the effect of ergometer recoil tension on upper limb recruitment and kinematics during the kayak stroke. Male kayakers (n = 10 performed 4 by 1 min on-ergometer exercise bouts at 85%VO2max at varying elastic recoil tension; EMG, stroke force and three-dimensional 3D kinematic data were recorded. While stationary recoil forces significantly increased across investigated tensions (125% increase, p < 0.001, no significant differences were detected in assessed force variables during the stroke cycle. In contrast, increasing tension induced significantly higher Anterior Deltoid (AD activity in the latter stages (70 to 90% of the cycle (p < 0.05. No significant differences were observed across tension levels for Triceps Brachii or Latissimus Dorsi. Kinematic analysis revealed that overhead arm movements accounted for 39 ± 16% of the cycle. Elbow angle at stroke cycle onset was 144 ± 10°; maximal elbow angle (151 ± 7° occurred at 78 ± 10% into the cycle. All kinematic markers moved to a more anterior position as tension increased. No significant change in wrist marker elevation was observed, while elbow and shoulder marker elevations significantly increased across tension levels (p < 0.05. In conclusion, data suggested that kayakers maintained normal upper limb kinematics via additional AD recruitment despite ergometer induced recoil forces

  9. Constraints on leisure time physical activity at a public university

    Directory of Open Access Journals (Sweden)

    Kubilay Öcal

    2014-09-01

    Full Text Available This study focuses on understanding constraints on leisure time physical activity (LTPA on a university campus. The survey study was conducted with public university students (n=563 living in dormitories. The 38-item, 8-dimension Leisure Time Physical Activity Constraints (LTPA-C Scale was used to investigate factors limiting LTPA. Age, gender, working status (i.e. part-time, non-working, program type (i.e. morning education, evening education, relationship status (i.e. in a relationship, not in a relationship, monthly expenses and body mass index (BMI category (i.e. underweight, normal weight, overweight, obese are key variables believed to affect LTPA-C. An initial confirmatory factor analysis was conducted to validate the structure of the scale, and frequency analysis, Pearson’s Correlation and t-tests were conducted to analyze the survey responses. Results showed the hierarchy of constraints for males (from high to low to be as follows: society, income, time, facility, willpower, skill perception, family, body perception. The hierarchy was nearly identical for females, except ‘willpower’ was found to be a greater constraint than ‘facility’; moreover, the differences in the rates at which males and females perceived ‘facility’ and ‘willpower’ to be constraints were statistically significant.The study findings indicate that by taking steps to improve the infrastructure of university campus facilities and organize group activities, university management can provide motivation and social support that can help to increase university student participation in LTPA.

  10. KINEMATICS AND CHEMISTRY OF STARS ALONG THE SAGITTARIUS TRAILING TIDAL TAIL AND CONSTRAINTS ON THE MILKY WAY MASS DISTRIBUTION

    Energy Technology Data Exchange (ETDEWEB)

    Carlin, Jeffrey L.; Majewski, Steven R.; Patterson, Richard J. [Department of Astronomy, University of Virginia, P.O. Box 400325, Charlottesville, VA 22904-4325 (United States); Casetti-Dinescu, Dana I.; Girard, Terrence M. [Astronomy Department, Yale University, P.O. Box 208101, New Haven, CT 06520-8101 (United States); Law, David R., E-mail: jc4qn@mail.astro.virginia.edu, E-mail: carlij@rpi.edu [Department of Physics and Astronomy, University of California, Los Angeles, CA 90095 (United States)

    2012-01-01

    We present three-dimensional (3D) kinematics of Sagittarius (Sgr) trailing tidal debris in six fields located 70 Degree-Sign -130 Degree-Sign along the stream from the Sgr dwarf galaxy core. The data are from our proper-motion (PM) survey of Kapteyn's Selected Areas, in which we have measured accurate PMs to faint magnitudes in {approx}40' Multiplication-Sign 40' fields evenly spaced across the sky. The radial velocity (RV) signature of Sgr has been identified among our follow-up spectroscopic data in four of the six fields and combined with mean PMs of spectroscopically confirmed members to derive space motions of Sgr debris based on {approx}15-64 confirmed stream members per field. These kinematics are compared to predictions of the Law and Majewski model of Sgr disruption; we find reasonable agreement with model predictions in RVs and PMs along Galactic latitude. However, an upward adjustment of the local standard of rest velocity ({Theta}{sub LSR}) from its standard 220 km s{sup -1} to at least 232 {+-} 14 km s{sup -1} (and possibly as high as 264 {+-} 23 km s{sup -1}) is necessary to bring 3D model debris kinematics and our measurements into agreement. Satisfactory model fits that simultaneously reproduce known position, distance, and RV trends of the Sgr tidal streams, while significantly increasing {Theta}{sub LSR}, could only be achieved by increasing the Galactic bulge and disk mass while leaving the dark matter halo fixed to the best-fit values from Law and Majewski. We derive low-resolution spectroscopic abundances along this stretch of the Sgr stream and find a constant [Fe/H] {approx} -1.15 (with {approx}0.5 dex scatter in each field-typical for dwarf galaxy populations) among the four fields with reliable measurements. A constant metallicity suggests that debris along the {approx}60 Degree-Sign span of this study was all stripped from Sgr on the same orbital passage.

  11. Kinematics of hip, knee, ankle of the young and elderly Chinese people during kneeling activity*

    OpenAIRE

    Zhou, Hai; Wang, Dong-Mei; Liu, Tao-ran; Zeng, Xiang-sen; Wang, Cheng-tao

    2012-01-01

    Objective: The purpose of this study was to measure the kinematics of the lower limbs of Chinese people during normal kneeling activity, as such data could be valuable in designing joint prosthesis and arthroplasty that meet the needs of Chinese citizens’ daily activities. Methods: Thirty young and twenty elderly Chinese participants with no personal history of joint diseases were recruited, and matched by age (average age: 23.8 years for the young group, 60.8 years for the elderly group). Ea...

  12. Dimensionality Reduction in Controlling Articulated Snake Robot for Endoscopy Under Dynamic Active Constraints

    Science.gov (United States)

    Kwok, Ka-Wai; Tsoi, Kuen Hung; Vitiello, Valentina; Clark, James; Chow, Gary C. T.; Luk, Wayne; Yang, Guang-Zhong

    2014-01-01

    This paper presents a real-time control framework for a snake robot with hyper-kinematic redundancy under dynamic active constraints for minimally invasive surgery. A proximity query (PQ) formulation is proposed to compute the deviation of the robot motion from predefined anatomical constraints. The proposed method is generic and can be applied to any snake robot represented as a set of control vertices. The proposed PQ formulation is implemented on a graphic processing unit, allowing for fast updates over 1 kHz. We also demonstrate that the robot joint space can be characterized into lower dimensional space for smooth articulation. A novel motion parameterization scheme in polar coordinates is proposed to describe the transition of motion, thus allowing for direct manual control of the robot using standard interface devices with limited degrees of freedom. Under the proposed framework, the correct alignment between the visual and motor axes is ensured, and haptic guidance is provided to prevent excessive force applied to the tissue by the robot body. A resistance force is further incorporated to enhance smooth pursuit movement matched to the dynamic response and actuation limit of the robot. To demonstrate the practical value of the proposed platform with enhanced ergonomic control, detailed quantitative performance evaluation was conducted on a group of subjects performing simulated intraluminal and intracavity endoscopic tasks. PMID:24741371

  13. GPS Rapid Static and Kinematic Positioning Based on GPS Active Network

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    This paper presents a data processing strategy for GPS kinematic positioning by using a GPS active network to model the GPS errors in double difference observable.Firstly,the double difference residuals are estimated between the reference stations in the active network.Then the errors at a user station are predicted as the network corrections to user measurements,based on the location of the user.Finally conventional kinematic positioning algorithms can be applied to determine the position of the user station.As an example,continuous 24-hour GPS data in March 2001 has been processed by this method.It clearly demonstrates that,after applying these corrections to a user within the network,both the success rate for ambiguity resolution and the positioning accuracy have been significantly improved.

  14. First spectro-interferometric survey of Be stars I. Observations and constraints on the disks geometry and kinematics

    CERN Document Server

    Meilland, Anthony; Kanaan, Samer; Stee, Philippe; Petrov, Romain

    2011-01-01

    Context. Classical Be stars are hot non-supergiant stars surrounded by a gaseous circumstellar disk responsible for the observed infrared-excess and emission lines. The phenomena involved in the disk formation still remain highly debated. Aims. To progress in the understanding of the physical process or processes responsible for the mass-ejection and test the hypothesis that they depends on the stellar parameters, we initiate a survey on the circumstellar environment of the brightest Be stars. Methods. To achieve this goal, we used spectro-interferometry, the only technique combining high spectral (R=12000) and high spatial (\\thetamin=4mas) resolutions. Observations were carried out at Paranal observatory with the VLTI/AMBER instrument. We concentrate our observations on the Br{\\gamma} emission line to be able to study the kinematics within the circumstellar disk. Our sample is composed of eight bright classical Be stars : \\alph Col, \\kappa CMa, \\omega Car, p Car, \\delta Cen, \\mu Cen, \\alpha Ara, and o Aqr. R...

  15. Paleomagnetism of the Stanislaus Group, CA reveals revised stratigraphy, Walker Lane kinematics, and radio-isotopic constraints on C5 magnetic subchrons

    Science.gov (United States)

    Pluhar, C. J.; Wright, T. J.; Fischer, C. P.; Busby, C. J.

    2007-12-01

    Paleomagnetic study of the c.a. 9.2-10.3 Ma Stanislaus Group of intercalated latite (trachyandesite) lavas, ignimbrites and accessory sediments at three localities in Mono county California reveals: 1) a detailed, revised stratigraphy for the Stanislaus group, 2) kinematic constraints on the part of the Walker Lane since Stanislaus group emplacement, and 3) two age-constrained magnetic subchrons during chron C5N recorded by latites that had previously only been identified in seafloor magnetic anomalies. The revised stratigraphy results from detailed magnetostratigraphy combined with previous 40Ar/39Ar geochronologic constraints and stratigraphic studies. We find the lowermost unit, Table Mountain Latite, to consist of 23 or more individual lava flows falling into 5 magnetic (mostly normal) polarity zones, indicating that these rocks span at least 40,000 years of geologic time, based on the expected duration of magnetic reversals. Overlying Table Mountain Latite is the reversed-polarity Tollhouse Flat member of the Eureka Valley Tuff as described by previous authors. In the Sweetwater Roadless Area, thought to be proximal to the Stanislaus eruptive center, latite lava of both normal and reversed polarity are emplaced ontop of the Tollhouse Flat Member. Normal-polarity By Day member and normal-polarity Upper Member lie at very top of entire sequence. We find no field evidence for the normal polarity Dardanelle Formation latite flow at the top of the Group as had been previously reported by other workers. Instead, the Dardanelle formation member likely corresponds to the latite lava(s) between the By Day and Tollhouse Flat Eureka Valley Tuff. Based on previous 40Ar/39Ar dating, the two reversed zones within our magnetostratigraphy correspond to two of the proposed reversed subchrons/excursions during chron C5N. Direct dating of these reversed units may lead to future improvements to the magnetic polarity timescale for C5N. Our paleomagnetic results from three study

  16. CONSTRAINTS ON THE MAGELLANIC CLOUDS' INTERACTION FROM THE DISTRIBUTION OF OB STARS AND THE KINEMATICS OF GIANTS

    Energy Technology Data Exchange (ETDEWEB)

    Casetti-Dinescu, Dana I.; Girard, Terrence M.; Van Altena, William F. [Astronomy Department, Yale University, P.O. Box 208101, New Haven, CT 06520-8101 (United States); Vieira, Katherine, E-mail: dana.casetti@yale.edu, E-mail: terry.girard@yale.edu, E-mail: william.vanaltena@yale.edu, E-mail: kvieira@cida.ve [Centro de Investigaciones de Astronomia, Apartado Postal 264, Merida 5101-A (Venezuela, Bolivarian Republic of)

    2012-07-10

    Young, OB-type candidates are identified in a {approx}7900 deg{sup 2} region encompassing the Large and Small Magellanic Clouds (LMC/SMC) periphery, the Bridge, part of the Magellanic Stream (MS), and Leading Arm (LA). Selection is based on UV, optical, and IR photometry from existing large-area surveys and proper motions from the Southern Proper Motion 4 (SPM4) catalog. The spatial distribution of these young star candidates shows (1) a well-populated SMC wing which continues westward with two branches partially surrounding the SMC, (2) a rather narrow path from the SMC wing eastward toward the LMC which is offset by 1 Degree-Sign -2 Degree-Sign from the high-density H I ridge in the Bridge, (3) a well-populated periphery of the LMC dominated by clumps of stars at the ends of the LMC bar, and (4) a few scattered candidates in the MS and two overdensities in the LA regions above and below the Galactic plane. Additionally, a proper-motion analysis is made of a radial-velocity-selected sample of red giants and supergiants in the LMC, previously shown to be a kinematically and chemically distinct subgroup, most likely captured from the SMC. SPM4 proper motions of these stars also indicate they are distinct from the LMC population. The observational results presented here, combined with the known orbits of the Clouds and other aspects of the LMC morphology, suggest an off-center, moderate to highly inclined collision between the SMC and the LMC's disk that took place between 100 and 200 Myr ago.

  17. Kinematic constraints on buckling a lithospheric-scale orocline along the northern margin of Gondwana: A geologic synthesis

    Science.gov (United States)

    Weil, A. Brandon; Gutiérrez-Alonso, G.; Johnston, S. T.; Pastor-Galán, D.

    2013-01-01

    The Paleozoic Variscan orogeny was a large-scale collisional event involving amalgamation of multiple continents and micro-continents. Existing data, suggests oroclinal buckling of an originally near-linear convergent margin during the last stages of Variscan deformation in the late Paleozoic. Closure of the Rheic Ocean resulted in E-W shortening (present-day coordinates) in the Carboniferous, producing a near linear N-S trending, east-verging belt. Subsequent N-S shortening near the Carb-Permian boundary resulted in oroclinal buckling. This late-stage orogenic event remains an enigmatic part of final Pangea amalgamation. The present-day arc curvature of the Variscan has inspired many tectonic models, with little agreement between them. While there is general consensus that two separate phases of deformation occurred, various models consider that curvature was caused by: dextral transpression around a Gondwana indentor; strike-slip wrench tectonics; or a change in tectonic transport direction due to changing stress fields. More recent models explain the curvature as an orocline, with potentially two opposite-facing bends, caused by secondary rotations. Deciphering the kinematic history of curved orogens is difficult, and requires establishment of two deformation phases: an initial compressive phase that forms a relatively linear belt, and a second phase that causes vertical-axis rotation of the orogenic limbs. Historically the most robust technique to accurately quantify vertical axis-rotation in curved orogens is paleomagnetic analysis, but recently other types of data, including fracture, geochemical, petrologic, paleo-current and calcite twin data, have been used to corroborate secondary buckling. A review of existing and new Variscan data from Iberia is presented that argues for secondary buckling of an originally linear orogenic system. Together, these data constrain oroclinal buckling of the Cantabrian Orocline to have occurred in about 10 Ma during the

  18. Fundamental Activity Constraints Lead to Specific Interpretations of the Connectome

    Science.gov (United States)

    van Albada, Sacha J.; Diesmann, Markus; Helias, Moritz

    2017-01-01

    The continuous integration of experimental data into coherent models of the brain is an increasing challenge of modern neuroscience. Such models provide a bridge between structure and activity, and identify the mechanisms giving rise to experimental observations. Nevertheless, structurally realistic network models of spiking neurons are necessarily underconstrained even if experimental data on brain connectivity are incorporated to the best of our knowledge. Guided by physiological observations, any model must therefore explore the parameter ranges within the uncertainty of the data. Based on simulation results alone, however, the mechanisms underlying stable and physiologically realistic activity often remain obscure. We here employ a mean-field reduction of the dynamics, which allows us to include activity constraints into the process of model construction. We shape the phase space of a multi-scale network model of the vision-related areas of macaque cortex by systematically refining its connectivity. Fundamental constraints on the activity, i.e., prohibiting quiescence and requiring global stability, prove sufficient to obtain realistic layer- and area-specific activity. Only small adaptations of the structure are required, showing that the network operates close to an instability. The procedure identifies components of the network critical to its collective dynamics and creates hypotheses for structural data and future experiments. The method can be applied to networks involving any neuron model with a known gain function. PMID:28146554

  19. Shaping tissues by balancing active forces and geometric constraints

    Science.gov (United States)

    Foolen, Jasper; Yamashita, Tadahiro; Kollmannsberger, Philip

    2016-02-01

    The self-organization of cells into complex tissues during growth and regeneration is a combination of physical-mechanical events and biochemical signal processing. Cells actively generate forces at all stages in this process, and according to the laws of mechanics, these forces result in stress fields defined by the geometric boundary conditions of the cell and tissue. The unique ability of cells to translate such force patterns into biochemical information and vice versa sets biological tissues apart from any other material. In this topical review, we summarize the current knowledge and open questions of how forces and geometry act together on scales from the single cell to tissues and organisms, and how their interaction determines biological shape and structure. Starting with a planar surface as the simplest type of geometric constraint, we review literature on how forces during cell spreading and adhesion together with geometric constraints impact cell shape, stress patterns, and the resulting biological response. We then move on to include cell-cell interactions and the role of forces in monolayers and in collective cell migration, and introduce curvature at the transition from flat cell sheets to three-dimensional (3D) tissues. Fibrous 3D environments, as cells experience them in the body, introduce new mechanical boundary conditions and change cell behaviour compared to flat surfaces. Starting from early work on force transmission and collagen remodelling, we discuss recent discoveries on the interaction with geometric constraints and the resulting structure formation and network organization in 3D. Recent literature on two physiological scenarios—embryonic development and bone—is reviewed to demonstrate the role of the force-geometry balance in living organisms. Furthermore, the role of mechanics in pathological scenarios such as cancer is discussed. We conclude by highlighting common physical principles guiding cell mechanics, tissue patterning and

  20. Development of Kinematic Graphs of Median Nerve during Active Finger Motion: Implications of Smartphone Use.

    Directory of Open Access Journals (Sweden)

    Hoi-Chi Woo

    Full Text Available Certain hand activities cause deformation and displacement of the median nerve at the carpal tunnel due to the gliding motion of tendons surrounding it. As smartphone usage escalates, this raises the public's concern whether hand activities while using smartphones can lead to median nerve problems.The aims of this study were to 1 develop kinematic graphs and 2 investigate the associated deformation and rotational information of median nerve in the carpal tunnel during hand activities.Dominant wrists of 30 young adults were examined with ultrasonography by placing a transducer transversely on their wrist crease. Ultrasound video clips were recorded when the subject performing 1 thumb opposition with the wrist in neutral position, 2 thumb opposition with the wrist in ulnar deviation and 3 pinch grip with the wrist in neutral position. Six still images that were separated by 0.2-second intervals were then captured from the ultrasound video for the determination of 1 cross-sectional area (CSA, 2 flattening ratio (FR, 3 rotational displacement (RD and 4 translational displacement (TD of median nerve in the carpal tunnel, and these collected information of deformation, rotational and displacement of median nerve were compared between 1 two successive time points during a single hand activity and 2 different hand motions at the same time point. Finally, kinematic graphs were constructed to demonstrate the mobility of median nerve during different hand activities.Performing different hand activities during this study led to a gradual reduction in CSA of the median nerve, with thumb opposition together with the wrist in ulnar deviation causing the greatest extent of deformation of the median nerve. Thumb opposition with the wrist in ulnar deviation also led to the largest extent of TD when compared to the other two hand activities of this study. Kinematic graphs showed that the motion pathways of median nerve during different hand activities were complex

  1. New Neighbors from 2MASS: Activity and Kinematics at the Bottom of the Main Sequence

    Science.gov (United States)

    Gizis, John E.; Monet, David G.; Reid, I. Neill; Kirkpatrick, J. Davy; Liebert, James; Williams, Rik J.

    2000-08-01

    We have combined 2MASS and POSS II data in a search for nearby ultracool (later than M6.5) dwarfs with Ksmass function that is smooth across the stellar/substellar limit. We show the observed frequency of Hα emission peaks at ~100% for M7 dwarfs and then decreases for cooler dwarfs. In absolute terms, however, as measured by the ratio of Hα to bolometric luminosity, none of the ultracool M dwarfs can be considered very active compared to earlier M dwarfs, and we show that the decrease that begins at spectral type M6 continues to the latest L dwarfs. We find that flaring is common among the coolest M dwarfs and estimate the frequency of flares at 7% or higher. We show that the kinematics of relatively active (EW>6 Å) ultracool M dwarfs are consistent with an ordinary old disk stellar population, while the kinematics of inactive ultracool M dwarfs are more typical of a 0.5 Gyr old population. The early L dwarfs in the sample have kinematics consistent with old ages, suggesting that the hydrogen-burning limit is near spectral types L2-L4. We use the available data on M and L dwarfs to show that chromospheric activity drops with decreasing mass and temperature and that at a given (M8 or later) spectral type, the younger field (brown) dwarfs are less active than many of the older, more massive field stellar dwarfs. Thus, contrary to the well-known stellar age-activity relationship, low activity in field ultracool dwarfs can be an indication of comparative youth and substellar mass.

  2. The perception and constraints towards recreational activity among female students

    Directory of Open Access Journals (Sweden)

    Azlan Ahmad Kamal

    2010-12-01

    Full Text Available More often than not, male students are seen to be more active in recreation activity than female students. To investigate this matter, a study was done on the female recreational activity participation. This study investigated the perception and constraints towards recreation activity among female students in a university in Malaysia. This study used a questionnaire regarding the recreation activity to collect the findings. Sixty respondents have been selected randomly as the subject for this study. All the information that is obtained from the questionnaire has been collected and analyzed using SPSS. It was found recreation is most often perceived as ‘extreme sports’ by female students. Moreover, most of the female students perceived themselves as participating regularly in recreational activity. The reasons for not participating in recreational activity are of lack of time, low energy level, lack of participants, lack of facilities and money. It was also found female students prefer outdoor activities such as camping, abseiling and wall climbing. Future studies should compare the perception of male and female students’ on recreational activity.

  3. New Neighbors from 2MASS Activity and Kinematics at the Bottom of the Main Sequence

    CERN Document Server

    Gizis, J E; Reid, I N; Kirkpatrick, J D; Liebert, J; Williams, R J; Gizis, John E.; Monet, David G.; Liebert, James; Williams, Rik J.

    2000-01-01

    We have combined 2MASS and POSS II data in a search for nearby ultracool (later than M6.5) dwarfs with K_s6 Angstroms) ultracool M dwarfs are consistent with an ordinary old disk stellar population, while the kinematics of inactive ultracool M dwarfs are more typical of a 0.5 Gyr old population. The early L dwarfs in the sample have kinematics consistent with old ages, suggesting that the hydrogen burning limit is near spectral types L2-L4. We use the available data on M and L dwarfs to show that chromospheric activity drops with decreasing mass and temperature, and that at a given (M8 or later) spectral type, the younger field (brown) dwarfs are less active than many of the older, more massive field stellar dwarfs. Thus, contrary to the well-known stellar age-activity relationship, low activity in field ultracool dwarfs can be an indication of comparative youth and substellar mass.

  4. The Industrial Robot Kinematics Calibration Based on the Position Constraint%基于位置约束的工业机器人运动学标定∗

    Institute of Scientific and Technical Information of China (English)

    熊杰; 杨东升; 王允森; 袁晓慧

    2016-01-01

    Given the standard DH method was limited to describe parallel joint, MDH method was adopted to establish the robot kinematics. Based on the end position constraint, a general method was proposed to es-tablish the linear equations for structure parameter identification. To solve the degradation problems in the coefficient matrix of the equations, starting from the Jacobian matrix of the kinematics, the reasons for the degradation was analyzed. It was the theoretical basis to select the structural parameters. The conversion be-tween robot base coordinate system and the measurement coordinate system was discussed and then a simple calibration method based on the cross-bar was designed without coordinate conversion. After the simulation conducted in matlab, MOTOMAN-MH6 robot was calibrated by this method. After calibration, the cross bar length error calculated under teaching readings reduced from 4mm to less than 1mm. The results show that the calibration method is effective.%鉴于标准DH方法在描述平行关节时存在问题,采用MDH方法建立机器人的运动学,提出基于末端位置约束关系建立线性方程组进行结构参数辨识的一般方法。针对方程组系数矩阵退化的问题,从运动学的雅可比矩阵入手,分析了退化的原因,为结构参数选择提供了理论依据。讨论了机器人基坐标系和测量坐标系转换的问题,设计了一种无需坐标系转换的基于十字型杆件的简易标定方法。基于matlab进行仿真后,采用该方法标定MOTOMAN-MH6机器人,标定后,按照示教器读数计算的十字型杆件长度误差从4 mm降低到1 mm以内,说明该方法是有效的。

  5. A kinematically beamed, low energy pulsed neutron source for active interrogation

    Science.gov (United States)

    Dietrich, Dan; Hagmann, Chris; Kerr, Phil; Nakae, Les; Rowland, Mark; Snyderman, Neal; Stoeffl, Wolfgang; Hamm, Robert

    2005-12-01

    We are developing a new active interrogation system based on a kinematically focused low energy neutron beam. The key idea is that one of the defining characteristics of special nuclear materials (SNM) is the ability for low energy or thermal neutrons to induce fission. Thus by using low energy neutrons for the interrogation source we can accomplish three goals: (1) energy discrimination allows us to measure the prompt fast fission neutrons produced while the interrogation beam is on; (2) neutrons with an energy of approximately 60-100 keV do not fission 238U and Thorium, but penetrate bulk material nearly as far as high energy neutrons do and (3) below about 100 keV neutrons lose their energy by kinematical collisions rather than via the nuclear (n, 2n) or (n, n‧) processes thus further simplifying the prompt neutron induced background. 60 keV neutrons create a low radiation dose and readily thermal capture in normal materials, thus providing a clean spectroscopic signature of the intervening materials. The kinematically beamed source also eliminates the need for heavy backward and sideway neutron shielding. We have designed and built a very compact pulsed neutron source, based on an RFQ proton accelerator and a lithium target. We are developing fast neutron detectors that are nearly insensitive to the ever-present thermal neutron and neutron capture induced gamma ray background. The detection of only a few high energy fission neutrons in time correlation with the linac pulse will be a clear indication of the presence of SNM.

  6. Using activity-based costing and theory of constraints to guide continuous improvement in managed care.

    Science.gov (United States)

    Roybal, H; Baxendale, S J; Gupta, M

    1999-01-01

    Activity-based costing and the theory of constraints have been applied successfully in many manufacturing organizations. Recently, those concepts have been applied in service organizations. This article describes the application of activity-based costing and the theory of constraints in a managed care mental health and substance abuse organization. One of the unique aspects of this particular application was the integration of activity-based costing and the theory of constraints to guide process improvement efforts. This article describes the activity-based costing model and the application of the theory of constraint's focusing steps with an emphasis on unused capacities of activities in the organization.

  7. Measuring supermassive black holes with gas kinematics: the active S0 galaxy NGC 3998

    CERN Document Server

    De Francesco, G; Marconi, A; Francesco, Giovanna De; Capetti, Alessandro; Marconi, Alessandro

    2006-01-01

    We present results from a kinematical study of the gas in the nucleus of the active S0 galaxy NGC 3998 obtained from archival HST/STIS long-slit spectra. We analyzed the emission lines profiles and derived the map of the gas velocity field. The observed velocity curves are consistent with gas in regular rotation around the galaxy's center. By modeling the surface brightness distribution and rotation curve of the H_alfa emission line we found that the observed kinematics of the circumnuclear gas can be accurately reproduced by adding to the stellar mass component a compact dark mass (black hole) of M_bh = 2.7(-2.0,+2.4) 10**8 M_sun (uncertainties at a 2 sigma level); the radius of its sphere of influence (R_sph ~ 0".16) is well resolved at the HST resolution. The BH mass estimate in NGC 3998 is in good agreement with both the M_bh vs. M_bul (with an upward scatter by a factor of ~2) and M_bh vs. sigma correlations (with a downward scatter by a factor of ~3-7, depending on the form adopted for the dependence of...

  8. Kinematic matrix theory and universalities in self-propellers and active swimmers

    Science.gov (United States)

    Nourhani, Amir; Lammert, Paul E.; Borhan, Ali; Crespi, Vincent H.

    2014-06-01

    We describe an efficient and parsimonious matrix-based theory for studying the ensemble behavior of self-propellers and active swimmers, such as nanomotors or motile bacteria, that are typically studied by differential-equation-based Langevin or Fokker-Planck formalisms. The kinematic effects for elementary processes of motion are incorporated into a matrix, called the "kinematrix," from which we immediately obtain correlators and the mean and variance of angular and position variables (and thus effective diffusivity) by simple matrix algebra. The kinematrix formalism enables us recast the behaviors of a diverse range of self-propellers into a unified form, revealing universalities in their ensemble behavior in terms of new emergent time scales. Active fluctuations and hydrodynamic interactions can be expressed as an additive composition of separate self-propellers.

  9. Kinematic matrix theory and universalities in self-propellers and active swimmers.

    Science.gov (United States)

    Nourhani, Amir; Lammert, Paul E; Borhan, Ali; Crespi, Vincent H

    2014-06-01

    We describe an efficient and parsimonious matrix-based theory for studying the ensemble behavior of self-propellers and active swimmers, such as nanomotors or motile bacteria, that are typically studied by differential-equation-based Langevin or Fokker-Planck formalisms. The kinematic effects for elementary processes of motion are incorporated into a matrix, called the "kinematrix," from which we immediately obtain correlators and the mean and variance of angular and position variables (and thus effective diffusivity) by simple matrix algebra. The kinematrix formalism enables us recast the behaviors of a diverse range of self-propellers into a unified form, revealing universalities in their ensemble behavior in terms of new emergent time scales. Active fluctuations and hydrodynamic interactions can be expressed as an additive composition of separate self-propellers.

  10. Kinematics of hip, knee, ankle of the young and elderly Chinese people during kneeling activity

    Institute of Scientific and Technical Information of China (English)

    Hai ZHOU; Dong-mei WANG; Tao-ran LIU; Xiang-sen ZENG; Cheng-tao WANG

    2012-01-01

    Objective:The purpose of this study was to measure the kinematics of the lower limbs of Chinese people during normal kneeling activity,as such data could be valuable in designing joint prosthesis and arthroplasty that meet the needs of Chinese citizens' daily activities.Methods:Thirty young and twenty elderly Chinese participants with no personal history of joint diseases were recruited,and matched by age (average age:23.8 years for the young group,60.8 years for the elderly group).Each participant performed six trials during which three-dimensional (3D) kinematics data were collected and the means of the 3D angles of the ankle,knee,and hip joints of two groups were calculated.Results:There were no obvious differences between the two groups in the knee and ankle joints.The mean range of knee flexion was 139.6° for the young group and 140.9° for the elderly group.The mean range of ankle flexion was 35.7° for the young group and 37.6° for the elderly group.The maximal eccentric flexion at the hip joint was 67.5° for the young group compared to 100.5° for the elderly group.Conclusions:The elderly uses more hip flexion angles than the young when assuming the kneeling posture.The ranges of motion obtained during kneeling activity are greater than the reported mean ranges of motion achieved following joint arthroplasty.The data could be valuable in establishing criteria for lower limb prosthetics and rehabilitation protocol for the Chinese population.

  11. Acute changes in kinematic and muscle activity patterns in habitually shod rearfoot strikers while running barefoot.

    Science.gov (United States)

    Strauts, Janina; Vanicek, Natalie; Halaki, Mark

    2016-01-01

    The aim of this study was to observe changes in the kinematics and muscle activities when barefoot running was initially adopted by six habitually shod, recreational rearfoot striking runners. Participants ran on a treadmill shod for 5 min, completed 3 × 10-min intervals of barefoot running and then completed a final minute of shod running at a self-selected pace. Dependent variables (speed, joint angles at foot-contact, joint range of motion (ROM), mean and peak electromyography (EMG) activity) were compared across conditions using repeated measures ANOVAs. Anterior pelvic tilt and hip flexion significantly decreased during barefoot conditions at foot contact. The ROM for the trunk, pelvis, knee and ankle angles decreased during the barefoot conditions. Mean EMG activity was reduced for biceps femoris, gastrocnemius lateralis and tibialis anterior during barefoot running. The peak activity across the running cycle decreased in biceps femoris, vastus medialis, gastrocnemius medialis and tibialis anterior during barefoot running. During barefoot running, tibialis anterior activity significantly decreased during the pre-activation and initial contact phases; gastrocnemius lateralis and medialis activity significantly decreased during the push-off phase. Barefoot running caused immediate biomechanical and neuromuscular adaptations at the hip and pelvis, which persisted when the runners donned their shoes, indicating that some learning had occurred during an initial short bout of barefoot running.

  12. ~100 Ma Lu-Hf eclogite ages from Koralpe and Saualpe (Austroalpine nappes, Austria): New constraints for the kinematics of Eoalpine subduction

    Science.gov (United States)

    Miladinova, Irena; Froitzheim, Nikolaus; Nagel, Thorsten; Janák, Marian; Münker, Carsten

    2016-04-01

    The Koralpe and Saualpe complexes are part of the Austroalpine basement nappe system. They represent the largest region in the Eastern Alps exposing high-pressure metamorphic rocks from the Cretaceous Eoalpine orogenic event and also contain the type locality for eclogite. The grade of the Cretaceous metamorphism in the Eastern Alps increases to the southeast, with maximum pressures and temperatures reaching up to 3.5 GPa and 850 °C in the Pohorje Mountains (Janak et al., 2015). The estimated P-T-conditions for the eclogites from Saualpe and Koralpe are 2-2.2 GPa and 600-740 °C (Miller & Thöni 1997, Thöni et al. 2008). Here we present a new Lu-Hf isotopic study of the eclogites from the Hohl locality in the southern Koralpe, and from the Grünburgerbach and Wolfsberger Hütte localities in the southern Saualpe. Two-point isochrones from samples of Hohl and Wolfsberger Hütte based on one whole rock and one garnet separate yield ages of 99.2 ± 1.1 Ma and 101.7 ± 2 Ma, respectively. Two eclogite samples from Grünburgerbach give garnet-omphacite-whole rock ages of 100.3 ± 1 Ma and 101.79 ± 0.92 Ma, identical within error. The garnets in the eclogite from Hohl display a homogenous composition with no zoning of major elements, whereas the garnets of the samples from Grünburgerbach show an enrichment of Mn in the cores and lower contents towards the rims, which indicates prograde garnet growth during increasing P and T. The ages are therefore related to burial during subduction. These new Lu-Hf garnet ages are slightly older than the Lu-Hf garnet age data from Pohorje (~95 Ma; Sandmann et al. 2011, Thöni et al. 2008), which also date burial. If Koralpe/Saualpe and Pohorje would belong to one continuous crustal unit subducted and exhumed "en bloc" in a southeast-dipping subduction zone, the opposite age difference would be expected. Our results show that this is not the case and represent important constraints for a more realistic kinematic model. Janak, M

  13. Differences between kinematic synergies and muscle synergies during two-digit grasping

    Directory of Open Access Journals (Sweden)

    Michele eTagliabue

    2015-03-01

    Full Text Available The large number of mechanical degrees of freedom of the hand is not fully exploited during actual movements such as grasping. Usually, angular movements in various joints tend to be coupled, and EMG activities in different hand muscles tend to be correlated. The occurrence of covariation in the former was termed kinematic synergies, in the latter muscle synergies. This study addresses two questions: (i Whether kinematic and muscle synergies can simultaneously accommodate for kinematic and kinetic constraints. (ii If so, whether there is an interrelation between kinematic and muscle synergies. We used a reach-grasp-and-pull paradigm and recorded the hand kinematics as well as 8 surface EMGs. Subjects had to either perform a precision grip or side grip and had to modify their grip force in order to displace an object against a low or high load. The analysis was subdivided into three epochs: reach, grasp-and-pull, and static hold. Principal component analysis (PCA, temporal or static was performed separately for all three epochs, in the kinematic and in the EMG domain. PCA revealed that (i Kinematic- and muscle-synergies can simultaneously accommodate kinematic (grip type and kinetic task constraints (load condition. (ii Upcoming grip and load conditions of the grasp are represented in kinematic- and muscle-synergies already during reach. Phase plane plots of the principal muscle-synergy against the principal kinematic synergy revealed (iii that the muscle-synergy is linked (correlated, and in phase advance to the kinematic synergy during reach and during grasp-and-pull. Furthermore (iv, pair-wise correlations of EMGs during hold suggest that muscle-synergies are (in part implemented by coactivation of muscles through common input. Together, these results suggest that kinematic synergies have (at least in part their origin not just in muscular activation, but in synergiestic muscle activation. In short: kinematic synergies may result from muscle

  14. Shoulder kinematics and spatial pattern of trapezius electromyographic activity in real and virtual environments.

    Directory of Open Access Journals (Sweden)

    Afshin Samani

    Full Text Available The design of an industrial workstation tends to include ergonomic assessment steps based on a digital mock-up and a virtual reality setup. Lack of interaction and system fidelity is often reported as a main issue in such virtual reality applications. This limitation is a crucial issue as thorough ergonomic analysis is required for an investigation of the biomechanics. In the current study, we investigated the biomechanical responses of the shoulder joint in a simulated assembly task for comparison with the biomechanical responses in virtual environments. Sixteen male healthy novice subjects performed the task on three different platforms: real (RE, virtual (VE, and virtual environment with force feedback (VEF with low and high precision demands. The subjects repeated the task 12 times (i.e., 12 cycles. High density electromyography from the upper trapezius and rotation angles of the shoulder joint were recorded and split into the cycles. The angular trajectories and velocity profiles of the shoulder joint angles over a cycle were computed in 3D. The inter-subject similarity in terms of normalized mutual information on kinematics and electromyography was investigated. Compared with RE the task in VE and VEF was characterized by lower kinematic maxima. The inter-subject similarity in RE compared with intra-subject similarity across the platforms was lower in terms of movement trajectories and greater in terms of trapezius muscle activation. The precision demand resulted in lower inter- and intra-subject similarity across platforms. The proposed approach identifies biomechanical differences in the shoulder joint in both VE and VEF compared with the RE platform, but these differences are less marked in VE mostly due to technical limitations of co-localizing the force feedback system in the VEF platform.

  15. 3D shoulder kinematics for static vs dynamic and passive vs active testing conditions.

    Science.gov (United States)

    Robert-Lachaine, Xavier; Allard, Paul; Godbout, Véronique; Begon, Mickael

    2015-09-18

    Shoulder motion analysis provides clinicians with references of normal joint rotations. Shoulder joints orientations assessment is often based on series of static positions, while clinicians perform either passive or active tests and exercises mostly in dynamic. These conditions of motion could modify joint coordination and lead to discrepancies with the established references. Hence, the objective was to evaluate the influence of static vs dynamic and passive vs active testing conditions on shoulder joints orientations. Twenty asymptomatic subjects setup with 45 markers on the upper limb and trunk were tracked by an optoelectronic system. Static positions (30°, 60°, 90° and 120° of thoracohumeral elevation) and dynamic motion both in active condition and passively mobilised by an examiner were executed. Three-dimensional sternoclavicular, acromioclavicular, scapulothoracic and glenohumeral joint angles (12 in total) representing the distal segment orientation relative to the proximal segment orientation were estimated using a shoulder kinematical chain model. Separate four-way repeated measures ANOVA were applied on the 12 joint angles with factors of static vs dynamic, passive vs active, thoracohumeral elevation angle (30°, 60°, 90° and 120°) and plane of elevation (frontal and sagittal). Scapulothoracic lateral rotation progressed more during arm elevation in static than in dynamic gaining 4.2° more, and also in passive than in active by 6.6°. Glenohumeral elevation increased more during arm elevation in active than in passive by 4.4°. Shoulder joints orientations are affected by the testing conditions, which should be taken into consideration for data acquisition, inter-study comparison or clinical applications.

  16. Can generic knee joint models improve the measurement of osteoarthritic knee kinematics during squatting activity?

    Science.gov (United States)

    Clément, Julien; Dumas, Raphaël; Hagemeister, Nicola; de Guise, Jaques A

    2017-01-01

    Knee joint kinematics derived from multi-body optimisation (MBO) still requires evaluation. The objective of this study was to corroborate model-derived kinematics of osteoarthritic knees obtained using four generic knee joint models used in musculoskeletal modelling - spherical, hinge, degree-of-freedom coupling curves and parallel mechanism - against reference knee kinematics measured by stereo-radiography. Root mean square errors ranged from 0.7° to 23.4° for knee rotations and from 0.6 to 9.0 mm for knee displacements. Model-derived knee kinematics computed from generic knee joint models was inaccurate. Future developments and experiments should improve the reliability of osteoarthritic knee models in MBO and musculoskeletal modelling.

  17. Active constraints selection based semi-supervised dimensionality in ensemble subspaces

    Institute of Scientific and Technical Information of China (English)

    Jie Zeng; Wei Nie; Yong Zhang

    2015-01-01

    Semi-supervised dimensionality reduction (SSDR) has attracted an increasing amount of attention in this big-data era. Many algorithms have been developed with a smal number of pairwise constraints to achieve performances comparable to those of ful y supervised methods. However, one chal enging problem with semi-supervised approaches is the appropriate choice of the constraint set, including the cardinality and the composition of the constraint set, which to a large extent, affects the performance of the resulting algorithm. In this work, we address the problem by incorporating ensemble subspace and active learning into dimen-sionality reduction and propose a new algorithm, termed as global and local scatter based SSDR with active pairwise constraints selection in ensemble subspaces (SSGL-ESA). Unlike traditional methods that select the supervised information in one subspace, we pick up pairwise constraints in ensemble subspace, where a novel active learning algorithm is designed with both exploration and filtering to generate informative pairwise constraints. The auto-matic constraint selection approach proposed in this paper can be generalized to be used with al constraint-based semi-supervised learning algorithms. Comparative experiments are conducted on two face database and the results validate the effectiveness of the proposed method.

  18. Active load path adaption in a simple kinematic load-bearing structure due to stiffness change in the structure's supports

    Science.gov (United States)

    Gehb, C. M.; Platz, R.; Melz, T.

    2016-09-01

    Load-bearing structures with kinematic functions enable and disable degrees of freedom and are part of many mechanical engineering applications. The relative movement between a wheel and the body of a car or a landing gear and an aircraft fuselage are examples for load-bearing systems with defined kinematics. In most cases, the load is transmitted through a predetermined load path to the structural support interfaces. However, unexpected load peaks or varying health condition of the system's supports, which means for example varying damping and stiffness characteristics, may require an active adjustment of the load path. However, load paths transmitted through damaged or weakened supports can be the reason for reduced comfort or even failure. In this paper a simplified 2D two mass oscillator with two supports is used to numerically investigate the potential of controlled adaptive auxiliary kinematic guidance elements in a load-bearing structure to adapt the load path depending on the stiffness change, representing damage of the supports. The aim is to provide additional forces in the auxiliary kinematic guidance elements for two reasons. On the one hand, one of the two supports that may become weaker through stiffness change will be relieved from higher loading. On the other hand, tilting due to different compliance in the supports will be minimized. Therefore, shifting load between the supports during operation could be an effective option.

  19. Accretion/jet activity and narrow [O III] kinematics in young radio galaxies

    Institute of Scientific and Technical Information of China (English)

    Andrew; HUMPHREY

    2010-01-01

    We estimate black hole masses and Edenton ratios for a sample of 81 young radio galaxies,which includes 42 compact steep-spectrum(CSS) and 39 gigahertz-peaked spectrum(GPS) sources.We find that the average black hole(BH) mass of these young radio galaxies is〈log Mbh〉-8.3,which is less than that of radio loud QSOs and low redshift radio galaxies(〈 log Mbh〉-9.0).The CSS/GPS sources have relatively high Eddington ratios,with an average value of〈log Lbol/LEdd〉=-0.75,which are similar to those of narrow line Seyfert 1 galaxies(NLS1s).This suggests that young radio galaxies may not only be in the early stages of their radio activity,but also in the early stage of their accretion activity.We find that the young radio galaxies,as a class,systematically deviate from the Mbh-σ relation defined by nearby inactive galaxies,when using σ[O III] as a surrogate for stellar velocity dispersion σ.We also find that the deviation of the [O III] line width,Δσ =σ[O III]-σ[pred],is correlated with the Eddington ratio;sources with Lbol/LEdd-1 have the largest deviations,which are similar to those of radio quiet QSOs/NLS1s(i.e.,sources in which the radio jets are absent or weak),and where σ[pred] is calculated from the Tremaine et al.relation using our estimated BH masses.A similar result has been obtained for 9 linear radio Seyfert galaxies.On the basis of these results,we suggest that,in addition to the possible jet-gas interactions,accretion activities may also play an important role in shaping the kinematics of the narrow [O III] line in young radio galaxies.

  20. Kinematic analysis of the daily activity of drinking from a glass in a population with cervical spinal cord injury

    Directory of Open Access Journals (Sweden)

    de los Reyes-Guzmán Ana

    2010-08-01

    Full Text Available Abstract Background Three-dimensional kinematic analysis equipment is a valuable instrument for studying the execution of movement during functional activities of the upper limbs. The aim of this study was to analyze the kinematic differences in the execution of a daily activity such as drinking from a glass between two groups of patients with tetraplegia and a control group. Methods A total of 24 people were separated into three groups for analysis: 8 subjects with metameric level C6 tetraplegia, 8 subjects with metameric level C7 tetraplegia and 8 control subjects (CG. A set of active markers that emit infrared light were positioned on the upper limb. Two scanning units were used to record the sessions. The activity of drinking from a glass was broken down into a series of clearly identifiable phases to facilitate analysis. Movement times, velocities, and the joint angles of the shoulder, elbow and wrist in the three spatial planes were the variables analyzed. Results The most relevant differences between the three groups were in the wrist. Wrist palmar flexion during the back transport phase was greater in the patients with C6 and C7 tetraplegia than in the CG, whereas the highest wrist dorsal flexion values were in forward transport in the subjects with C6 or C7 tetraplegia, who required complete activation of the tenodesis effect to complete grasping. Conclusions A detailed description was made of the three-dimensional kinematic analysis of the task of drinking from a glass in healthy subjects and in two groups of patients with tetraplegia. This was a useful application of kinematic analysis of upper limb movement in a clinical setting. Better knowledge of the execution of this movement in each of these groups allows therapeutic recommendations to be specifically adapted to the functional deficit present. This information can be useful in designing wearable robots to compensate the performance of AVD, such as drinking, in people with

  1. A Double-Ring Algorithm for Modeling Solar Active Regions: Unifying Kinematic Dynamo Models and Surface Flux-Transport Simulations

    CERN Document Server

    Muñoz-Jaramillo, Andrés; Martens, Petrus C H; Yeates, Anthony R

    2010-01-01

    The emergence of tilted bipolar active regions and the dispersal of their flux, mediated via processes such as diffusion, differential rotation and meridional circulation is believed to be responsible for the reversal of the Sun's polar field. This process (commonly known as the Babcock-Leighton mechanism) is usually modeled as a near-surface, spatially distributed $\\alpha$-effect in kinematic mean-field dynamo models. However, this formulation leads to a relationship between polar field strength and meridional flow speed which is opposite to that suggested by physical insight and predicted by surface flux-transport simulations. With this in mind, we present an improved double-ring algorithm for modeling the Babcock-Leighton mechanism based on active region eruption, within the framework of an axisymmetric dynamo model. Using surface flux-transport simulations we first show that an axisymmetric formulation -- which is usually invoked in kinematic dynamo models -- can reasonably approximate the surface flux dy...

  2. Effect of Kayak Ergometer Elastic Tension on Upper Limb EMG Activity and 3D Kinematics.

    Science.gov (United States)

    Fleming, Neil; Donne, Bernard; Fletcher, David

    2012-01-01

    Despite the prevalence of shoulder injury in kayakers, limited published research examining associated upper limb kinematics and recruitment patterns exists. Altered muscle recruitment patterns on-ergometer vs. on-water kayaking were recently reported, however, mechanisms underlying changes remain to be elucidated. The current study assessed the effect of ergometer recoil tension on upper limb recruitment and kinematics during the kayak stroke. Male kayakers (n = 10) performed 4 by 1 min on-ergometer exercise bouts at 85%VO2max at varying elastic recoil tension; EMG, stroke force and three-dimensional 3D kinematic data were recorded. While stationary recoil forces significantly increased across investigated tensions (125% increase, p kayakers maintained normal upper limb kinematics via additional AD recruitment despite ergometer induced recoil forces. Key pointsKayak ergometer elastic tension significantly alters Anterior Deltoid recruitment patterns.Kayakers maintain optimal arm kinematics despite changing external forces via altered shoulder muscle recruitment.Overhead arm movements account for a high proportion of the kayak stroke cycle.

  3. Mid-J CO shock tracing observations of infrared dark clouds II Low-J CO constraints on excitation, depletion, and kinematics

    CERN Document Server

    Pon, A; Caselli, P; Fontani, F; Palau, A; Butler, M J; Kaufman, M; Jiménez-Serra, I; Tan, J C

    2015-01-01

    Infrared dark clouds are kinematically complex molecular structures in the interstellar medium that can host sites of massive star formation. We present 4 square arcminute maps of the 12CO, 13CO, and C18O J = 3 to 2 lines from selected locations within the C and F (G028.37+00.07 and G034.43+00.24) infrared dark clouds (IRDCs), as well as single pointing observations of the 13CO and C18O J = 2 to 1 lines towards three cores within these clouds. We derive CO gas temperatures throughout the maps and find that CO is significantly frozen out within these IRDCs. We find that the CO depletion tends to be the highest near column density peaks, with maximum depletion factors between 5 and 9 in IRDC F and between 16 and 31 in IRDC C. We also detect multiple velocity components and complex kinematic structure in both IRDCs. Therefore, the kinematics of IRDCs seem to point to dynamically evolving structures yielding dense cores with considerable depletion factors.

  4. STELLAR KINEMATICS AND STRUCTURAL PROPERTIES OF VIRGO CLUSTER DWARF EARLY-TYPE GALAXIES FROM THE SMAKCED PROJECT. III. ANGULAR MOMENTUM AND CONSTRAINTS ON FORMATION SCENARIOS

    Energy Technology Data Exchange (ETDEWEB)

    Toloba, E.; Guhathakurta, P. [UCO/Lick Observatory, University of California, Santa Cruz, 1156 High Street, Santa Cruz, CA 95064 (United States); Boselli, A.; Boissier, S. [Aix Marseille Universit, CNRS, LAM (Laboratoire d' Astrophysique de Marseille) UMR 7326, F-13388 Marseille (France); Peletier, R. F. [Kapteyn Astronomical Institute, Postbus 800, 9700 AV Groningen (Netherlands); Emsellem, E. [European Southern Observatory, Karl-Schwarzschild-Strasse 2, D-85748 Garching (Germany); Lisker, T. [Astronomisches Rechen-Institut, Zentrum für Astronomie der Universität Heidelberg, Mönchhofstraße 12-14, D-69120 Heidelberg (Germany); Van de Ven, G. [Max Planck Institute for Astronomy, Königstuhl 17, D-69117 Heidelberg (Germany); Simon, J. D.; Adams, J. J.; Benson, A. J. [Observatories of the Carnegie Institution for Science, 813 Santa Barbara Street, Pasadena, CA 91101 (United States); Falcón-Barroso, J.; Ryś, A. [Instituto de Astrofísica de Canarias, Vía Láctea s/n, E-38200 La Laguna, Tenerife (Spain); Den Brok, M. [Department of Physics and Astronomy, University of Utah, Salt Lake City, UT 84112 (United States); Gorgas, J. [Departamento de Astrofísica y Ciencias de la Atmósfera, Universidad Complutense de Madrid, E-28040 Madrid (Spain); Hensler, G. [Department of Astrophysics, University of Vienna, Türkenschanzstraße 17, A-1180 Vienna (Austria); Janz, J. [Centre for Astrophysics and Supercomputing, Swinburne University, Hawthorn, VIC 3122 (Australia); Laurikainen, E.; Salo, H. [Division of Astronomy, Department of Physics, University of Oulu, P.O. Box 3000, FI-90014 Oulu (Finland); Paudel, S., E-mail: toloba@ucolick.org [Korea Astronomy and Space Science Institute, Daejeon 305-348 (Korea, Republic of)

    2015-02-01

    We analyze the stellar kinematics of 39 dwarf early-type galaxies (dEs) in the Virgo Cluster. Based on the specific stellar angular momentum λ{sub Re} and the ellipticity, we find 11 slow rotators and 28 fast rotators. The fast rotators in the outer parts of the Virgo Cluster rotate significantly faster than fast rotators in the inner parts of the cluster. Moreover, 10 out of the 11 slow rotators are located in the inner 3° (D < 1 Mpc) of the cluster. The fast rotators contain subtle disk-like structures that are visible in high-pass filtered optical images, while the slow rotators do not exhibit these structures. In addition, two of the dEs have kinematically decoupled cores and four more have emission partially filling in the Balmer absorption lines. These properties suggest that Virgo Cluster dEs may have originated from late-type star-forming galaxies that were transformed by the environment after their infall into the cluster. The correlation between λ{sub Re} and the clustercentric distance can be explained by a scenario where low luminosity star-forming galaxies fall into the cluster, their gas is rapidly removed by ram-pressure stripping, although some of it can be retained in their core, their star formation is quenched but their stellar kinematics are preserved. After a long time in the cluster and several passes through its center, the galaxies are heated up and transformed into slow rotating dEs.

  5. Walking while performing working memory tasks changes the prefrontal cortex hemodynamic activations and gait kinematics

    Directory of Open Access Journals (Sweden)

    Ming-I Brandon Lin

    2016-05-01

    Full Text Available BackgroundIncreasing evidence suggests that walking while performing a concurrent task negatively influences gait performance. However, it remains unclear how higher-level cognitive processes and coordination of limb movements are altered in challenging walking environments. This study investigated the influence of cognitive task complexity and walking road condition on the neutral correlates of executive function and postural control in dual-task walking. MethodsTwenty-four healthy young adults completed a series of overground walks with three walking road conditions (wide, narrow, with obstacles with and without the concurrent n-back working memory tasks of two complexity levels (1-back and 3-back. Prefrontal brain activation was assessed by functional near-infrared spectroscopy. A three-dimensional motion analysis system was used simultaneously to measure gait performance and lower-extremity kinematics. Repeated measures analysis of variance were performed to examine the differences between the conditions. ResultsIn comparison with standing still, participants showed lower n-back task accuracy while walking, with the worst performance from the road with obstacles. Spatiotemporal gait parameters, lower-extremity joint movements, and the relative changes in oxygenated hemoglobin (HbO concentration levels were all significantly different across the task complexity and walking path conditions. While dual-tasking participants were found to flex their hips and knees less, leading to a slower gait speed, longer stride time, shorter step length, and greater gait variability than during normal walking. For narrow-road walking, smaller ankle dorsiflexion and larger hip flexion were observed, along with a reduced gait speed. Obstacle negotiation was mainly characterized by increased gait variability than other conditions. HbO levels appeared to be lower during dual-task walking than normal walking. Compared to wide and obstacle conditions, walking on

  6. Relativistic Kinematics

    CERN Document Server

    Sahoo, Raghunath

    2016-01-01

    This lecture note covers Relativistic Kinematics, which is very useful for the beginners in the field of high-energy physics. A very practical approach has been taken, which answers "why and how" of the kinematics useful for students working in the related areas.

  7. Stumbling reactions during perturbed walking: Neuromuscular reflex activity and 3-D kinematics of the trunk - A pilot study.

    Science.gov (United States)

    Müller, Juliane; Müller, Steffen; Engel, Tilman; Reschke, Antje; Baur, Heiner; Mayer, Frank

    2016-04-11

    Reflex activity of the lower leg muscles involved when compensating for falls has already been thoroughly investigated. However, the trunk׳s role in this compensation strategy remains unclear. The purpose of this study, therefore, was to analyze the kinematics and muscle activity of the trunk during perturbed walking. Ten subjects (29 ± 3 yr;79 ± 11 cm;74 ± 14 kg) walked (1m/s) on a split-belt treadmill, while 5 randomly timed, right-sided perturbations (treadmill belt deceleration: 40 m/s(2)) were applied. Trunk muscle activity was assessed with a 12-lead-EMG. Trunk kinematics were measured with a 3D-motion analysis system (12 markers framing 3 segments: upper thoracic area (UTA), lower thoracic area (LTA), lumbar area (LA)). The EMG-RMS [%] (0-200 ms after perturbation) was analyzed and then normalized to the RMS of normal walking. The total range of motion (ROM;[°]) for the extension/flexion, lateral flexion and rotation of each segment were calculated. Individual kinematic differences between walking and stumbling [%; ROM] were also computed. Data analysis was conducted descriptively, followed by one- and two-way ANOVAs (α=0.05). Stumbling led to an increase in ROM, compared to unperturbed gait, in all segments and planes. These increases ranged between 107 ± 26% (UTA/rotation) and 262 ± 132% (UTS/lateral flexion), significant only in lateral flexion. EMG activity of the trunk was increased during stumbling (abdominal: 665 ± 283%; back: 501 ± 215%), without significant differences between muscles. Provoked stumbling leads to a measurable effect on the trunk, quantifiable by an increase in ROM and EMG activity, compared to normal walking. Greater abdominal muscle activity and ROM of lateral flexion may indicate a specific compensation pattern occurring during stumbling.

  8. Radially extended kinematics and stellar populations of the massive ellipticals NGC1600, NGC4125 and NGC7619. Constraints on the outer dark halo density profile

    CERN Document Server

    Pu, S B; Fabricius, M H; Thomas, J; Bender, R; Han, Z

    2010-01-01

    We present high quality long slit spectra along the major and minor axes out to 1.5-2 Re (14-22 kpc) of three bright elliptical galaxies (NGC1600, NGC4125, NGC7619) obtained at the Hobby-Eberly Telescope (HET). We derive stellar kinematic profiles and Lick/IDS indices (Hbeta, Mgb, Fe5015, Fe5270, Fe5335, Fe5406). Moreover, for NGC4125 we derive gas kinematics and emission line strengths. We model the absorption line strengths using Simple Stellar Populations models that take into account the variation of [\\alpha/Fe] and derive ages, total metallicity and element abundances. Overall, we find that the three galaxies have old and [\\alpha/Fe] overabundant stellar populations with no significant gradients. The metallicity is supersolar at the center with a strong negative radial gradient. For NGC4125, several pieces of evidence point to a recent dissipational merger event. We calculate the broad band color profiles with the help of SSP models. All of the colors show sharp peaks at the center of the galaxies, mainl...

  9. Interactive activation and mutual constraint satisfaction in perception and cognition.

    Science.gov (United States)

    McClelland, James L; Mirman, Daniel; Bolger, Donald J; Khaitan, Pranav

    2014-08-01

    In a seminal 1977 article, Rumelhart argued that perception required the simultaneous use of multiple sources of information, allowing perceivers to optimally interpret sensory information at many levels of representation in real time as information arrives. Building on Rumelhart's arguments, we present the Interactive Activation hypothesis-the idea that the mechanism used in perception and comprehension to achieve these feats exploits an interactive activation process implemented through the bidirectional propagation of activation among simple processing units. We then examine the interactive activation model of letter and word perception and the TRACE model of speech perception, as early attempts to explore this hypothesis, and review the experimental evidence relevant to their assumptions and predictions. We consider how well these models address the computational challenge posed by the problem of perception, and we consider how consistent they are with evidence from behavioral experiments. We examine empirical and theoretical controversies surrounding the idea of interactive processing, including a controversy that swirls around the relationship between interactive computation and optimal Bayesian inference. Some of the implementation details of early versions of interactive activation models caused deviation from optimality and from aspects of human performance data. More recent versions of these models, however, overcome these deficiencies. Among these is a model called the multinomial interactive activation model, which explicitly links interactive activation and Bayesian computations. We also review evidence from neurophysiological and neuroimaging studies supporting the view that interactive processing is a characteristic of the perceptual processing machinery in the brain. In sum, we argue that a computational analysis, as well as behavioral and neuroscience evidence, all support the Interactive Activation hypothesis. The evidence suggests that

  10. Decoding Lower Limb Muscle Activity and Kinematics from Cortical Neural Spike Trains during Monkey Performing Stand and Squat Movements

    Science.gov (United States)

    Ma, Xuan; Ma, Chaolin; Huang, Jian; Zhang, Peng; Xu, Jiang; He, Jiping

    2017-01-01

    Extensive literatures have shown approaches for decoding upper limb kinematics or muscle activity using multichannel cortical spike recordings toward brain machine interface (BMI) applications. However, similar topics regarding lower limb remain relatively scarce. We previously reported a system for training monkeys to perform visually guided stand and squat tasks. The current study, as a follow-up extension, investigates whether lower limb kinematics and muscle activity characterized by electromyography (EMG) signals during monkey performing stand/squat movements can be accurately decoded from neural spike trains in primary motor cortex (M1). Two monkeys were used in this study. Subdermal intramuscular EMG electrodes were implanted to 8 right leg/thigh muscles. With ample data collected from neurons from a large brain area, we performed a spike triggered average (SpTA) analysis and got a series of density contours which revealed the spatial distributions of different muscle-innervating neurons corresponding to each given muscle. Based on the guidance of these results, we identified the locations optimal for chronic electrode implantation and subsequently carried on chronic neural data recordings. A recursive Bayesian estimation framework was proposed for decoding EMG signals together with kinematics from M1 spike trains. Two specific algorithms were implemented: a standard Kalman filter and an unscented Kalman filter. For the latter one, an artificial neural network was incorporated to deal with the nonlinearity in neural tuning. High correlation coefficient and signal to noise ratio between the predicted and the actual data were achieved for both EMG signals and kinematics on both monkeys. Higher decoding accuracy and faster convergence rate could be achieved with the unscented Kalman filter. These results demonstrate that lower limb EMG signals and kinematics during monkey stand/squat can be accurately decoded from a group of M1 neurons with the proposed

  11. Decoding Lower Limb Muscle Activity and Kinematics from Cortical Neural Spike Trains during Monkey Performing Stand and Squat Movements.

    Science.gov (United States)

    Ma, Xuan; Ma, Chaolin; Huang, Jian; Zhang, Peng; Xu, Jiang; He, Jiping

    2017-01-01

    Extensive literatures have shown approaches for decoding upper limb kinematics or muscle activity using multichannel cortical spike recordings toward brain machine interface (BMI) applications. However, similar topics regarding lower limb remain relatively scarce. We previously reported a system for training monkeys to perform visually guided stand and squat tasks. The current study, as a follow-up extension, investigates whether lower limb kinematics and muscle activity characterized by electromyography (EMG) signals during monkey performing stand/squat movements can be accurately decoded from neural spike trains in primary motor cortex (M1). Two monkeys were used in this study. Subdermal intramuscular EMG electrodes were implanted to 8 right leg/thigh muscles. With ample data collected from neurons from a large brain area, we performed a spike triggered average (SpTA) analysis and got a series of density contours which revealed the spatial distributions of different muscle-innervating neurons corresponding to each given muscle. Based on the guidance of these results, we identified the locations optimal for chronic electrode implantation and subsequently carried on chronic neural data recordings. A recursive Bayesian estimation framework was proposed for decoding EMG signals together with kinematics from M1 spike trains. Two specific algorithms were implemented: a standard Kalman filter and an unscented Kalman filter. For the latter one, an artificial neural network was incorporated to deal with the nonlinearity in neural tuning. High correlation coefficient and signal to noise ratio between the predicted and the actual data were achieved for both EMG signals and kinematics on both monkeys. Higher decoding accuracy and faster convergence rate could be achieved with the unscented Kalman filter. These results demonstrate that lower limb EMG signals and kinematics during monkey stand/squat can be accurately decoded from a group of M1 neurons with the proposed

  12. Change of Muscle Activity as Well as Kinematic and Kinetic Parameters during Headers after Core Muscle Fatigue

    Directory of Open Access Journals (Sweden)

    Stephan Becker

    2017-01-01

    Full Text Available In soccer, headers are a tactical measure and influenced by numerous factors. The goal of this study was to identify whether changes in kinematics and muscular activity, especially of the head-stabilizing muscles, occur during headers when the core musculature is fatigued. In two subgroups, muscular activity (12 amateur players, age 23.6 ± 4.2 years and kinematics and dynamics (29 amateur players, age 23.7 ± 2.8 years were examined during straight headers on a pendulum header. Data were collected before and after the core muscles were fatigued by an exercise program. Telemetric surface EMG, 3D acceleration sensor, force plate, and video recordings were used. Under fatigue, the activity of M. erector spinae and M. rectus abdominis was significantly reduced in the preparation phase of the header. The activity of M. sternocleidomastoideus was significantly increased during the jump phase, and the hip extension angle during maximum arched body tension was significantly reduced under fatigue. Jumping height, acceleration force impulse, and linear head acceleration were also significantly reduced. We conclude that fatigue of the core muscles affects the motion technique of the header and the activity of the muscle groups stabilizing the head. Therefore, the necessity of specific training in soccer should be emphasized from a medical-preventive point of view.

  13. On Implicit Active Constraints in Linear Semi-Infinite Programs with Unbounded Coefficients

    Energy Technology Data Exchange (ETDEWEB)

    Goberna, M. A., E-mail: mgoberna@ua.es [Alicante University, Dep. of Statistics and Operations Research (Spain); Lancho, G. A., E-mail: lanchoga@mixteco.utm.mx [Universidad Tecnologica de Mixteca, Instituto de Fisica y Matematicas (Mexico); Todorov, M. I., E-mail: maxim.todorov@udlap.mx [UDLA, Dep. of Physics and Mathematics (Mexico); Vera de Serio, V. N., E-mail: vvera@uncu.edu.ar [Universidad Nacional de Cuyo, Facultad de Ciencias Economicas, Instituto de Ciencias Basicas (Argentina)

    2011-04-15

    The concept of implicit active constraints at a given point provides useful local information about the solution set of linear semi-infinite systems and about the optimal set in linear semi-infinite programming provided the set of gradient vectors of the constraints is bounded, commonly under the additional assumption that there exists some strong Slater point. This paper shows that the mentioned global boundedness condition can be replaced by a weaker local condition (LUB) based on locally active constraints (active in a ball of small radius whose center is some nominal point), providing geometric information about the solution set and Karush-Kuhn-Tucker type conditions for the optimal solution to be strongly unique. The maintaining of the latter property under sufficiently small perturbations of all the data is also analyzed, giving a characterization of its stability with respect to these perturbations in terms of the strong Slater condition, the so-called Extended-Nuernberger condition, and the LUB condition.

  14. Exploring variation in active network size : Constraints and ego characteristics

    NARCIS (Netherlands)

    Roberts, Sam G. B.; Dunbar, Robin I. M.; Pollet, Thomas V.; Kuppens, Toon

    2009-01-01

    Studies of active personal networks have primarily focused on providing reliable estimates of the size of the network. In this study, we examine how compositional properties of the network and ego characteristics are related to Variation in network size. There was a negative relationship between mea

  15. Constraints on the Star Formation Rate in Active Galaxies

    CERN Document Server

    Kim, M; Im, M; Kim, Minjin; Ho, Luis C.; Im, Myungshin

    2006-01-01

    The [O II] 3727 emission line is often used as an indicator of star formation rate in extragalactic surveys, and it can be an equally effective tracer of star formation in systems containing luminous active galactic nuclei (AGNs). In order to investigate the ongoing star formation rate of the host galaxies of AGNs, we measured the strength of [O II] and other optical emission lines from a large sample (~ 3600) of broad-line (Type 1) AGNs selected from the Sloan Digital Sky Survey. We performed a set of photoionization calculations to help evaluate the relative contribution of stellar and nonstellar photoionization to the observed strength of [O II]. Consistent with the recent study of Ho (2005), we find that the observed [O II] emission can be explained entirely by photoionization from the AGN itself, with little or no additional contribution from HII regions. This indicates that the host galaxies of Type 1 AGNs experience very modest star formation concurrent with the optically active phase of the nucleus. B...

  16. Kinematics of the Neogene Terror Rift: Constraints from calcite twinning strain in AND-1B core, McMurdo Ice Shelf

    Science.gov (United States)

    Paulsen, T.; Wilson, T. J.; Demosthenous, C.; Millan, C.; Jarrard, R. D.; Laufer, A.

    2013-12-01

    Strain analyses of mechanically twinned calcite in veins and faults hosted by Neogene (13.6 Ma to 4.3 Ma) sedimentary and volcanic rocks recovered within the ANDRILL AND-1B drill core from the Terror Rift in the southern Ross Sea, Antarctica, yield prolate and oblate ellipsoids with principal shortening and extension strains ranging from 0.1% to 8.5%. The majority of samples show homogeneous coaxial strain predominantly characterized by subvertical shortening, which we attribute to lithostatic loading in an Andersonian normal faulting stress regime during sedimentary and ice sheet burial of the stratigraphic sequence. The overall paucity of a non-coaxial layer-parallel shortening signal in the AND-1B twin populations suggests that horizontal compressive stresses predicted by Neogene transtensional kinematic models for the rift system have been absent or of insufficient magnitude to cause a widespread noncoaxial strain overprint. Limited numbers of oriented samples yield a possible average ESE extension direction for the rift that is subparallel to other indicators of Neogene extension. The lack of horizontal shortening in the twin data suggests the Neogene Terror Rift system either lacks a strong longitudinal strike-slip component, or that spatial partitioning of strain controls the maximum shortening axes seen in rocks of this age.

  17. Extravehicular Activity Operations Concepts Under Communication Latency and Bandwidth Constraints

    Science.gov (United States)

    Beaton, Kara H.; Chappell, Steven P.; Abercromby, Andrew F. J.; Miller, Matthew J.; Nawotniak, Shannon Kobs; Hughes, Scott; Brady, Allyson; Lim, Darlene S. S.

    2017-01-01

    The Biologic Analog Science Associated with Lava Terrains (BASALT) project is a multi-year program dedicated to iteratively develop, implement, and evaluate concepts of operations (ConOps) and supporting capabilities intended to enable and enhance human scientific exploration of Mars. This pa-per describes the planning, execution, and initial results from the first field deployment, referred to as BASALT-1, which consisted of a series of 10 simulated extravehicular activities (EVAs) on volcanic flows in Idaho's Craters of the Moon (COTM) National Monument. The ConOps and capabilities deployed and tested during BASALT-1 were based on previous NASA trade studies and analog testing. Our primary research question was whether those ConOps and capabilities work acceptably when performing real (non-simulated) biological and geological scientific exploration under 4 different Mars-to-Earth communication conditions: 5 and 15 min one-way light time (OWLT) communication latencies and low (0.512 Mb/s uplink, 1.54 Mb/s downlink) and high (5.0 Mb/s uplink, 10.0 Mb/s downlink) bandwidth conditions representing the lower and higher limits of technical communication capabilities currently proposed for future human exploration missions. The synthesized results of BASALT-1 with respect to the ConOps and capabilities assessment were derived from a variety of sources, including EVA task timing data, network analytic data, and subjective ratings and comments regarding the scientific and operational acceptability of the ConOp and the extent to which specific capabilities were enabling and enhancing, and are presented here. BASALT-1 established preliminary findings that baseline ConOp, software systems, and communication protocols were scientifically and operationally acceptable with minor improvements desired by the "Mars" extravehicular (EV) and intravehicular (IV) crewmembers, but unacceptable with improvements required by the "Earth" Mission Support Center. These data will provide a

  18. Effect of Neck Muscle Strength and Anticipatory Cervical Muscle Activation on the Kinematic Response of the Head to Impulsive Loads

    Science.gov (United States)

    Eckner, James T.; Oh, Youkeun K.; Joshi, Monica S.; Richardson, James K.; Ashton-Miller, James A.

    2015-01-01

    Background Greater neck strength and activating the neck muscles to brace for impact are both thought to reduce an athlete's risk of concussion during a collision by attenuating the head's kinematic response after impact. However, the literature reporting the neck's role in controlling postimpact head kinematics is mixed. Furthermore, these relationships have not been examined in the coronal or transverse planes or in pediatric athletes. Hypotheses In each anatomic plane, peak linear velocity (DV) and peak angular velocity (Dv) of the head are inversely related to maximal isometric cervical muscle strength in the opposing direction (H1). Under impulsive loading, DV and Dv will be decreased during anticipatory cervical muscle activation compared with the baseline state (H2). Study Design Descriptive laboratory study. Methods Maximum isometric neck strength was measured in each anatomic plane in 46 male and female contact sport athletes aged 8 to 30 years. A loading apparatus applied impulsive test forces to athletes' heads in flexion, extension, lateral flexion, and axial rotation during baseline and anticipatory cervical muscle activation conditions. Multivariate linear mixed models were used to determine the effects of neck strength and cervical muscle activation on head DV and Dv. Results Greater isometric neck strength and anticipatory activation were independently associated with decreased head DV and Dv after impulsive loading across all planes of motion (all P\\.001). Inverse relationships between neck strength and head DV and Dv presented moderately strong effect sizes (r = 0.417 to r = 0.657), varying by direction of motion and cervical muscle activation. Conclusion In male and female athletes across the age spectrum, greater neck strength and anticipatory cervical muscle activation (“bracing for impact”) can reduce the magnitude of the head's kinematic response. Future studies should determine whether neck strength contributes to the observed sex and

  19. A Constraint Satisfaction Neural Network and Heuristic Combined Approach for Concurrent Activities Scheduling

    Institute of Scientific and Technical Information of China (English)

    YAN JiHong(闫纪红); WU Cheng(吴澄)

    2003-01-01

    Scheduling activities in concurrent product development process is of great sig-nificance to shorten development lead time and minimize the cost. Moreover, it can eliminate theunnecessary redesign periods and guarantee that serial activities can be executed as concurrently aspossible. This paper presents a constraint satisfaction neural network and heuristic combined ap-proach for concurrent activities scheduling. In the combined approach, the neural network is usedto obtain a feasible starting time of all the activities based on sequence constraints, the heuris-tic algorithm is used to obtain a feasible solution of the scheduling problem based on resourceconstraints. The feasible scheduling solution is obtained by a gradient optimization function. Sim-ulations have shown that the proposed combined approach is efficient and feasible with respect toconcurrent activities scheduling.

  20. Modelado de Materiales Compuestos por Elementos Finitos usando Restricciones Cinemáticas Finite Element Modeling of Composite Materials using Kinematic Constraints

    Directory of Open Access Journals (Sweden)

    Oscar E. Ruiz

    2009-12-01

    Full Text Available El propósito de este artículo es presentar simulaciones del comportamiento de materiales compuestos basado en restricciones cinemáticas entre las mismas fibras y entre las fibras y la resina circundante. En la revisión de literatura, los autores han encontrado que las restricciones cinemáticas no han sido plenamente explotadas para modelar materiales compuestos, probablemente debido a su alto costo computacional. El propósito de este articulo es exponer la implementación y resultados de tal modelo, usando Análisis por Elementos Finitos de restricciones geométricas prescritas a los nodos de la resina y las fibras. Las descripciones analíticas del comportamiento de materiales compuestos raramente aparecen. Muchas aproximaciones para describir materiales compuestos en capas son basadas en la teoría de funciones C1Z y C0 Z, tal como la Teoría Clásica de Capas (CLT. Estas teorías de funciones contienen significativas simplificaciones del material, especialmente para compuestos tejidos. Una aproximación hibrida para modelar materiales compuestos con Elementos Finitos (FEA fue desarrollada por Sidhu y Averill y adaptada por Li y Sherwood para materiales compuestos tejidos con polipropileno de vidrio.The purpose of this article is to present simulations of the behavior of composite materials based on kinematic restrictions among the fibers themselves and among fibers and the surrounding resine. In the literature review the authors have found that the kinematic restrictions have not been fully exploited for modeling composite materials, probably due to their high computational expense. The purpose of this article is to show the implementation and results of such a model, by using a Finite Element Analysis of geometric restrictions prescribed to the resine and fiber nodes. Closed analytic descriptions on behavior of layered composite materials are very rare. Many approaches to describe layered composite material are based on the theory of

  1. State-based decoding of hand and finger kinematics using neuronal ensemble and LFP activity during dexterous reach-to-grasp movements.

    Science.gov (United States)

    Aggarwal, Vikram; Mollazadeh, Mohsen; Davidson, Adam G; Schieber, Marc H; Thakor, Nitish V

    2013-06-01

    The performance of brain-machine interfaces (BMIs) that continuously control upper limb neuroprostheses may benefit from distinguishing periods of posture and movement so as to prevent inappropriate movement of the prosthesis. Few studies, however, have investigated how decoding behavioral states and detecting the transitions between posture and movement could be used autonomously to trigger a kinematic decoder. We recorded simultaneous neuronal ensemble and local field potential (LFP) activity from microelectrode arrays in primary motor cortex (M1) and dorsal (PMd) and ventral (PMv) premotor areas of two male rhesus monkeys performing a center-out reach-and-grasp task, while upper limb kinematics were tracked with a motion capture system with markers on the dorsal aspect of the forearm, hand, and fingers. A state decoder was trained to distinguish four behavioral states (baseline, reaction, movement, hold), while a kinematic decoder was trained to continuously decode hand end point position and 18 joint angles of the wrist and fingers. LFP amplitude most accurately predicted transition into the reaction (62%) and movement (73%) states, while spikes most accurately decoded arm, hand, and finger kinematics during movement. Using an LFP-based state decoder to trigger a spike-based kinematic decoder [r = 0.72, root mean squared error (RMSE) = 0.15] significantly improved decoding of reach-to-grasp movements from baseline to final hold, compared with either a spike-based state decoder combined with a spike-based kinematic decoder (r = 0.70, RMSE = 0.17) or a spike-based kinematic decoder alone (r = 0.67, RMSE = 0.17). Combining LFP-based state decoding with spike-based kinematic decoding may be a valuable step toward the realization of BMI control of a multifingered neuroprosthesis performing dexterous manipulation.

  2. Determining Inclinations of Active Galactic Nuclei Via Their Narrow-Line Region Kinematics - II. Correlation With Observed Properties

    CERN Document Server

    Fischer, T C; Kraemer, S B; Schmitt, H R; Turner, T J

    2014-01-01

    Active Galactic Nuclei (AGN) are axisymmetric systems to first order; their observed properties are likely strong functions of inclination with respect to our line of sight, yet the specific inclinations of all but a few AGN are generally unknown. By determining the inclinations and geometries of nearby Seyfert galaxies using the kinematics of their narrow-line regions (NLRs), and comparing them with observed properties, we find strong correlations between inclination and total hydrogen column density, infrared color, and H-beta full-width at half maximum (FWHM). These correlations provide evidence that the orientation of AGN with respect to our line of sight affects how we perceive them, beyond the Seyfert type dichotomy. They can also be used to constrain 3D models of AGN components such as the broad-line region and torus. Additionally, we find weak correlations between AGN luminosity and several modeled NLR parameters, which suggests that the NLR geometry and kinematics are dependent to some degree on the ...

  3. Barefoot vs common footwear: A systematic review of the kinematic, kinetic and muscle activity differences during walking.

    Science.gov (United States)

    Franklin, Simon; Grey, Michael J; Heneghan, Nicola; Bowen, Laura; Li, François-Xavier

    2015-09-01

    Habitual footwear use has been reported to influence foot structure with an acute exposure being shown to alter foot position and mechanics. The foot is highly specialised thus these changes in structure/position could influence functionality. This review aims to investigate the effect of footwear on gait, specifically focussing on studies that have assessed kinematics, kinetics and muscle activity between walking barefoot and in common footwear. In line with PRISMA and published guidelines, a literature search was completed across six databases comprising Medline, EMBASE, Scopus, AMED, Cochrane Library and Web of Science. Fifteen of 466 articles met the predetermined inclusion criteria and were included in the review. All articles were assessed for methodological quality using a modified assessment tool based on the STROBE statement for reporting observational studies and the CASP appraisal tool. Walking barefoot enables increased forefoot spreading under load and habitual barefoot walkers have anatomically wider feet. Spatial-temporal differences including, reduced step/stride length and increased cadence, are observed when barefoot. Flatter foot placement, increased knee flexion and a reduced peak vertical ground reaction force at initial contact are also reported. Habitual barefoot walkers exhibit lower peak plantar pressures and pressure impulses, whereas peak plantar pressures are increased in the habitually shod wearer walking barefoot. Footwear particularly affects the kinematics and kinetics of gait acutely and chronically. Little research has been completed in older age populations (50+ years) and thus further research is required to better understand the effect of footwear on walking across the lifespan.

  4. Rational kinematics

    CERN Document Server

    Angeles, Jorge

    1988-01-01

    A rational study of kinematics is a treatment of the subject based on invariants, i.e., quantities that remain essentially unchanged under a change of observer. An observer is understood to be a reference frame supplied with a clock (Truesdell 1966). This study will therefore include an introduction to invariants. The language of these is tensor analysis and multilinear algebra, both of which share many isomorphic relations, These subjects are treated in full detail in Ericksen (1960) and Bowen and Wang (1976), and hence will not be included here. Only a short account of notation and definitions will be presented. Moreover, definitions and basic concepts pertaining to the kinematics of rigid bodies will be also included. Although the kinematics of rigid bodies can be regarded as a particular case of the kinematics of continua, the former deserves attention on its own merits for several reasons. One of these is that it describes locally the motions undergone by continua. Another reason is that a whole area of ...

  5. Joint kinematic calculation based on clinical direct kinematic versus inverse kinematic gait models.

    Science.gov (United States)

    Kainz, H; Modenese, L; Lloyd, D G; Maine, S; Walsh, H P J; Carty, C P

    2016-06-14

    Most clinical gait laboratories use the conventional gait analysis model. This model uses a computational method called Direct Kinematics (DK) to calculate joint kinematics. In contrast, musculoskeletal modelling approaches use Inverse Kinematics (IK) to obtain joint angles. IK allows additional analysis (e.g. muscle-tendon length estimates), which may provide valuable information for clinical decision-making in people with movement disorders. The twofold aims of the current study were: (1) to compare joint kinematics obtained by a clinical DK model (Vicon Plug-in-Gait) with those produced by a widely used IK model (available with the OpenSim distribution), and (2) to evaluate the difference in joint kinematics that can be solely attributed to the different computational methods (DK versus IK), anatomical models and marker sets by using MRI based models. Eight children with cerebral palsy were recruited and presented for gait and MRI data collection sessions. Differences in joint kinematics up to 13° were found between the Plug-in-Gait and the gait 2392 OpenSim model. The majority of these differences (94.4%) were attributed to differences in the anatomical models, which included different anatomical segment frames and joint constraints. Different computational methods (DK versus IK) were responsible for only 2.7% of the differences. We recommend using the same anatomical model for kinematic and musculoskeletal analysis to ensure consistency between the obtained joint angles and musculoskeletal estimates.

  6. Kinematics and excitation of the nuclear spiral in the active galaxy Arp 102B

    CERN Document Server

    Couto, Guilherme S; Axon, David J; Robinson, Andrew; Kharb, Preeti; Riffel, Rogemar A

    2013-01-01

    We present a two-dimensional analysis of the gaseous excitation and kinematics of the inner 2.5 x 1.7 kpc^2 of the LINER/Seyfert 1 galaxy Arp 102B, from optical spectra obtained with the GMOS integral field spectrograph on the Gemini North telescope at a spatial resolution of 250 pc. Emission-line flux maps show the same two-armed nuclear spiral we have discovered in previous observations with the HST-ACS camera. One arm reaches 1 kpc to the east and the other 500 pc to the west, with a 8.4 GHz VLA bent radio jet correlating with the former. The gas density is highest (500 - 900 cm^(-3)) at the nucleus and in the northern border of the east arm, at a region where the radio jet seems to be deflected. Channel maps show blueshifts but also some redshifts at the eastern arm and jet location which can be interpreted as originated in the front and back walls of an outflow pushed by the radio jet, suggesting also that the outflow is launched close to the plane of the sky. We estimate a mass outflow rate along the ea...

  7. Kinematics of the anemic cluster galaxy NGC 4548 Is stripping still active?

    CERN Document Server

    Vollmer, B; Boselli, A; Balkowski, C; Duschl, W J

    1999-01-01

    We present new HI (20" resolution) and CO observations of NGC 4548, an anemic galaxy in the Virgo cluster. The atomic gas distribution shows a ring structure which is distorted at the northern edge. The overall rotation curve is derived with a tilted ring model. We compare our rotation curve with previous ones and discuss the differences. The velocity field of the CO pointings fit very well with the one of the atomic gas where they overlap. The CO emission permits to extend the rotation curve towards the galaxy centre. The molecular fraction is derived for the inner 120" x 120" centered on the galaxy. We compare the HI and CO emission to H_alpha line and optical blue emission maps. The bar in the centre favors star formation at the outer end of the bar. The HI intensity distribution and velocity field of the northern perturbation are deprojected with the help of a first order kinematical model. They are discussed in the framework of warps. It is concluded that the scenario of ram pressure stripping responsibl...

  8. A high-resolution spectroscopic survey of late-type stars: chromospheric activity, rotation, kinematics, and age

    CERN Document Server

    Lopez-Santiago, J; Galvez-Ortiz, M C; Crespo-Chacon, I; Martinez-Arnaiz, R M; Fernandez-Figueroa, M J; De Castro, E; Cornide, M

    2010-01-01

    Aims: We present a compilation of spectroscopic data from a survey of 144 chromospherically active young stars in the solar neighborhood which may be used to investigate different aspects of the formation and evolution of the solar neighborhood in terms of kinematics and stellar formation history. The data have already been used by us in several studies. With this paper, we make all these data accessible to the scientific community for future studies on different topics. Methods: We performed spectroscopic observations with echelle spectrographs to cover the entirety of the optical spectral range simultaneously. Standard data reduction was performed with the IRAF ECHELLE package. We applied the spectral subtraction technique to reveal chromospheric emission in the stars of the sample. The equivalent width of chromospheric emission lines was measured in the subtracted spectra and then converted to fluxes using equivalent width-flux relationships. Radial and rotational velocities were determined by the cross-co...

  9. Optimal operation of batch processes via the tracking of active constraints.

    Science.gov (United States)

    Bonvin, Dominique; Srinivasan, Bala

    2003-01-01

    This paper presents a new measurement-based optimization framework for batch processes whereby optimal operation can be achieved via the tracking of active constraints. It is shown that, under mild assumptions and to a first-order approximation, tracking the necessary conditions of optimality is equivalent to tracking active constraints (both during the batch and at the end of the batch). Thus the optimal input trajectories can be adjusted using measurements without the use of a model of the process. When only batch-end measurements are available, the proposed method leads itself to an efficient batch-to-batch optimization scheme. The approach is illustrated via the simulation of a semibatch reactor under uncertainty.

  10. Active semi-supervised community detection based on must-link and cannot-link constraints.

    Directory of Open Access Journals (Sweden)

    Jianjun Cheng

    Full Text Available Community structure detection is of great importance because it can help in discovering the relationship between the function and the topology structure of a network. Many community detection algorithms have been proposed, but how to incorporate the prior knowledge in the detection process remains a challenging problem. In this paper, we propose a semi-supervised community detection algorithm, which makes full utilization of the must-link and cannot-link constraints to guide the process of community detection and thereby extracts high-quality community structures from networks. To acquire the high-quality must-link and cannot-link constraints, we also propose a semi-supervised component generation algorithm based on active learning, which actively selects nodes with maximum utility for the proposed semi-supervised community detection algorithm step by step, and then generates the must-link and cannot-link constraints by accessing a noiseless oracle. Extensive experiments were carried out, and the experimental results show that the introduction of active learning into the problem of community detection makes a success. Our proposed method can extract high-quality community structures from networks, and significantly outperforms other comparison methods.

  11. Influence of Hatha yoga on physical activity constraints, physical fitness, and body image of breast cancer survivors: a pilot study.

    Science.gov (United States)

    Van Puymbroeck, Marieke; Schmid, Arlene; Shinew, Kimberly J; Hsieh, Pei-Chun

    2011-01-01

    Breast cancer survivors often experience changes in their perception of their bodies following surgical treatment. These changes in body image may increase self-consciousness and perceptions of physical activity constraints and reduce participation in physical activity. While the number of studies examining different types of yoga targeting women with breast cancer has increased, studies thus far have not studied the influence that Hatha yoga has on body image and physical activity constraints. The objective of this study was to explore the changes that occur in breast cancer survivors in terms of body image, perceived constraints, and physical fitness following an 8-week Hatha yoga intervention. This study used a nonrandomized two-group pilot study, comparing an 8-week Hatha yoga intervention with a light exercise group, both designed for women who were at least nine months post-treatment for breast cancer. Both quantitative and qualitative data were collected in the areas of body image, physical activity constraints, and physical fitness. Findings indicated that quantitatively, yoga participants experienced reductions in physical activity constraints and improvements in lower- and upper-body strength and flexibility, while control participants experienced improvements in abdominal strength and lower-body strength. Qualitative findings support changes in body image, physical activity constraints, and physical fitness for the participants in the yoga group. In conclusion, Hatha yoga may reduce constraints to physical activity and improve fitness in breast cancer survivors. More research is needed to explore the relationship between Hatha yoga and improvements in body image.

  12. Effects of a posture-sensing air seat device (PSASD) on kinematics and trunk muscle activity during continuous computer work.

    Science.gov (United States)

    Park, Se-Yeon; Yoo, Won-Gyu

    2011-01-01

    The prevalence and incidence of musculoskeletal disorders is high with computer workers, and poor sitting posture can be considered a factor contributing to low back discomfort. In the clinical literature, maintaining a neutral spinal curvature has been considered an optimal sitting posture. This study investigated the flexion and lateral flexion of trunk movements and trunk muscle activity during computer work with and without a posture-sensing air seat device (PSASD). By sensing a certain amount of increased pressure over the baseline, posture-related visual feedback was given to participants through the PSASD. Eleven regular computer workers participated in this study. PSASD had the function of alerting the subject to their poor posture by using visual feedback. Subjects performed 20 min of computer work with and without a PSASD. Surface electromyography was used to measure the activity of the erector spine and internal abdominal oblique. Kinematic data were obtained using an electrogoniometer. The results showed that the mean of trunk flexion and lateral flexion was significantly reduced with PSASD. The activity of the erector spine and internal oblique was significantly higher with the PSASD than without. Our findings indicated that the PSASD helps to prevent habitual poor posture by maintaining an erect sitting posture during prolonged computer work.

  13. The generalized Hill model: A kinematic approach towards active muscle contraction

    Science.gov (United States)

    Göktepe, Serdar; Menzel, Andreas; Kuhl, Ellen

    2014-12-01

    Excitation-contraction coupling is the physiological process of converting an electrical stimulus into a mechanical response. In muscle, the electrical stimulus is an action potential and the mechanical response is active contraction. The classical Hill model characterizes muscle contraction though one contractile element, activated by electrical excitation, and two non-linear springs, one in series and one in parallel. This rheology translates into an additive decomposition of the total stress into a passive and an active part. Here we supplement this additive decomposition of the stress by a multiplicative decomposition of the deformation gradient into a passive and an active part. We generalize the one-dimensional Hill model to the three-dimensional setting and constitutively define the passive stress as a function of the total deformation gradient and the active stress as a function of both the total deformation gradient and its active part. We show that this novel approach combines the features of both the classical stress-based Hill model and the recent active-strain models. While the notion of active stress is rather phenomenological in nature, active strain is micro-structurally motivated, physically measurable, and straightforward to calibrate. We demonstrate that our model is capable of simulating excitation-contraction coupling in cardiac muscle with its characteristic features of wall thickening, apical lift, and ventricular torsion.

  14. Lower Extremity Muscle Activation and Kinematics of Catchers When Throwing Using Various Squatting and Throwing Postures

    Directory of Open Access Journals (Sweden)

    Yi-Chien Peng, Kuo-Cheng Lo, Lin-Hwa Wang

    2015-09-01

    Full Text Available This study investigated the differences in joint motions and muscle activities of the lower extremities involved in various squatting postures. The motion capture system with thirty-one reflective markers attached on participants was used for motion data collection. The electromyography system was applied over the quadriceps, biceps femoris, tibialis anterior, and gastrocnemius muscles of the pivot and stride leg. The joint extension and flexion in wide squatting are greater than in general squatting (p = 0.005. Knee joint extension and flexion in general squatting are significantly greater than in wide squatting (p = 0.001. The adduction and abduction of the hip joint in stride passing are significantly greater than in step squatting (p = 0.000. Furthermore, the adduction and abduction of the knee joint in stride passing are also significantly greater than in step squatting (p = 0.000. When stride passing is performed, the muscle activation of the hamstring of the pivot foot in general squatting is significantly greater than in wide squatting (p < 0.05, and this difference continues to the stride period. Most catchers use a general or wide squatting width, exclusive of a narrow one. Therefore, the training design for strengthening the lower extremity muscles should consider the appropriateness of the common squat width to enhance squat-up performance. For lower limb muscle activation, wide squatting requires more active gastrocnemius and tibialis anterior muscles. Baseball players should extend the knee angle of the pivot foot before catching the ball.

  15. Constraint-induced movement therapy improves upper limb activity and participation in hemiplegic cerebral palsy: a systematic review

    Directory of Open Access Journals (Sweden)

    Hsiu-Ching Chiu

    2016-07-01

    Full Text Available Questions: Does constraint-induced movement therapy improve activity and participation in children with hemiplegic cerebral palsy? Does it improve activity and participation more than the same dose of upper limb therapy without restraint? Is the effect of constraint-induced movement therapy related to the duration of intervention or the age of the children? Design: Systematic review of randomised trials with meta-analysis. Participants: Children with hemiplegic cerebral palsy with any level of motor disability. Intervention: The experimental group received constraint-induced movement therapy (defined as restraint of the less affected upper limb during supervised activity practice of the more affected upper limb. The control group received no intervention, sham intervention, or the same dose of upper limb therapy. Outcome measures: Measures of upper limb activity and participation were used in the analysis. Results: Constraint-induced movement therapy was more effective than no/sham intervention in terms of upper limb activity (SMD 0.63, 95% CI 0.20 to 1.06 and participation (SMD 1.21, 95% CI 0.41 to 2.02. However, constraint-induced movement therapy was no better than the same dose of upper limb therapy without restraint either in terms of upper limb activity (SMD 0.05, 95% CI –0.21 to 0.32 or participation (SMD –0.02, 95% CI –0.34 to 0.31. The effect of constraint-induced movement therapy was not related to the duration of intervention or the age of the children. Conclusions: This review suggests that constraint-induced movement therapy is more effective than no intervention, but no more effective than the same dose of upper limb practice without restraint. Registration: PROSPERO CRD42015024665. [Chiu H-C, Ada L (2016 Constraint-induced movement therapy improves upper limb activity and participation in hemiplegic cerebral palsy: a systematic review. Journal of Physiotherapy 62: 130–137

  16. Constraints of recreational sport participation: measurement invariance and latent mean differences across sex and physical activity status.

    Science.gov (United States)

    Liu, Jing Dong; Chung, Pak Kwong; Chen, Wing Ping

    2014-10-01

    The purpose of the current study was to (a) examine the measurement invariance of the Constraint Scale of Sport Participation across sex and physical activity status among the undergraduate students (N = 630) in Hong Kong and (b) compare the latent mean differences across groups. Measurement invariance of the Constraint Scale of Sport Participation across sex of and physical activity status of the participants was examined first. With receiving support on the measurement invariance across groups, latent mean differences of the scores across groups were examined. Multi-group confirmatory factor analysis revealed that the configural, metric, scalar, and structural invariance of the scale was supported across groups. The results of latent mean differences suggested that the women reported significantly higher constraints on time, partner, psychology, knowledge, and interest than the men. The physically inactive participants reported significantly higher scores on all constraints except for accessibility than the physically active participants.

  17. Effects of Juvenile Idiopathic Arthritis on Kinematics and Kinetics of the Lower Extremities Call for Consequences in Physical Activities Recommendations

    Directory of Open Access Journals (Sweden)

    M. Hartmann

    2010-01-01

    Full Text Available Juvenile idiopathic arthritis (JIA patients (n=36 with symmetrical polyarticular joint involvement of the lower extremities and healthy controls (n=20 were compared concerning differences in kinematic, kinetic, and spatio-temporal parameters with 3D gait analysis. The aims of this study were to quantify the differences in gait between JIA patients and healthy controls and to provide data for more detailed sport activities recommendations. JIA-patients showed reduced walking speed and step length, strongly anterior tilted pelvis, reduced maximum hip extension, reduced knee extension during single support phase and reduced plantar flexion in push off. Additionally the roll-off procedure of the foot was slightly decelerated. The reduced push off motion in the ankle was confirmed by lower peaks in ankle moment and power. The gait of JIA-patients can be explained as a crouch-like gait with hyperflexion in hip and knee joints and less plantar flexion in the ankle. A preventive mobility workout would be recommendable to reduce these restrictions in the future. Advisable are sports with emphasis on extension in hip, knee, and ankle plantar flexion.

  18. First inverse-kinematics fission measurements in a gaseous active target

    Science.gov (United States)

    Rodríguez-Tajes, C.; Farget, F.; Acosta, L.; Alvarez-Pol, H.; Babo, M.; Boulay, F.; Caamaño, M.; Damoy, S.; Fernández-Domínguez, B.; Galaviz, D.; Grinyer, G. F.; Grinyer, J.; Harakeh, M. N.; Konczykowski, P.; Martel, I.; Pancin, J.; Randisi, G.; Renzi, F.; Roger, T.; Sánchez-Benítez, A. M.; Teubig, P.; Vandebrouck, M.

    2017-02-01

    The fission of a variety of actinides was induced by fusion and transfer reactions between a 238U beam and 12C nuclei, in the active target MAYA. The performance of MAYA was studied, as well as its capability to reconstruct the fission-fragment trajectories. Furthermore, a full characterization of the different transfer reactions was achieved, and the populated excitation-energy distributions were investigated as a function of the kinetic energy in the entrance channel. The ratio between transfer- and fusion-induced fission cross-sections was also determined, in order to investigate the competition between both reaction types and its evolution with the incident energy. The experimental results will be discussed with a view to forthcoming radioactive-ion beam facilities, and next-generation active-target setups.

  19. A conceptual framework for understanding thermal constraints on ectotherm activity with implications for predicting responses to global change.

    Science.gov (United States)

    Gunderson, Alex R; Leal, Manuel

    2015-12-09

    Activity budgets influence the expression of life history traits as well as population dynamics. For ectotherms, a major constraint on activity is environmental temperature. Nonetheless, we currently lack a comprehensive conceptual framework for understanding thermal constraints on activity, which hinders our ability to rigorously apply activity data to answer ecological and evolutionary questions. Here, we integrate multiple aspects of temperature-dependent activity into a single unified framework that has general applicability. We also provide examples of the implementation of this framework to address fundamental questions in ecology relating to climate change vulnerability and species' distributions using empirical data from a tropical lizard.

  20. The effect of timing electrical stimulation to robotic-assisted stepping on neuromuscular activity and associated kinematics.

    Science.gov (United States)

    Askari, Sina; Chao, TeKang; de Leon, Ray D; Won, Deborah S

    2013-01-01

    Results of previous studies raise the question of how timing neuromuscular functional electrical stimulation (FES) to limb movements during stepping might alter neuromuscular control differently than patterned stimulation alone. We have developed a prototype FES system for a rodent model of spinal cord injury (SCI) that times FES to robotic treadmill training (RTT). In this study, one group of rats (n = 6) was trained with our FES+RTT system and received stimulation of the ankle flexor (tibialis anterior [TA]) muscle timed according to robot-controlled hind-limb position (FES+RTT group); a second group (n = 5) received a similarly patterned stimulation, randomly timed with respect to the rats' hind-limb movements, while they were in their cages (randomly timed stimulation [RS] group). After 4 wk of training, we tested treadmill stepping ability and compared kinematic measures of hind-limb movement and electromyography (EMG) activity in the TA. The FES+RTT group stepped faster and exhibited TA EMG profiles that better matched the applied stimulation profile during training than the RS group. The shape of the EMG profile was assessed by "gamma," a measure that quantified the concentration of EMG activity during the early swing phase of the gait cycle. This gamma measure was 112% higher for the FES+RTT group than for the RS group. The FES+RTT group exhibited burst-to-step latencies that were 41% shorter and correspondingly exhibited a greater tendency to perform ankle flexion movements during stepping than the RS group, as measured by the percentage of time the hind limb was either dragging or in withdrawal. The results from this study support the hypothesis that locomotor training consisting of FES timed to hind-limb movement improves the activation of hind-limb muscle more so than RS alone. Our rodent FES+RTT system can serve as a tool to help further develop this combined therapy to target appropriate neurophysiological changes for locomotor control.

  1. The effect of timing electrical stimulation to robotic-assisted stepping on neuromuscular activity and associated kinematics

    Directory of Open Access Journals (Sweden)

    Sina Askari, MS

    2013-08-01

    Full Text Available Results of previous studies raise the question of how timing neuromuscular functional electrical stimulation (FES to limb movements during stepping might alter neuromuscular control differently than patterned stimulation alone. We have developed a prototype FES system for a rodent model of spinal cord injury (SCI that times FES to robotic treadmill training (RTT. In this study, one group of rats (n = 6 was trained with our FES+RTT system and received stimulation of the ankle flexor (tibialis anterior [TA] muscle timed according to robot-controlled hind-limb position (FES+RTT group; a second group (n = 5 received a similarly patterned stimulation, randomly timed with respect to the rats’ hind-limb movements, while they were in their cages (randomly timed stimulation [RS] group. After 4 wk of training, we tested treadmill stepping ability and compared kinematic measures of hind-limb movement and electromyography (EMG activity in the TA. The FES+RTT group stepped faster and exhibited TA EMG profiles that better matched the applied stimulation profile during training than the RS group. The shape of the EMG profile was assessed by "gamma," a measure that quantified the concentration of EMG activity during the early swing phase of the gait cycle. This gamma measure was 112% higher for the FES+RTT group than for the RS group. The FES+RTT group exhibited burst-to-step latencies that were 41% shorter and correspondingly exhibited a greater tendency to perform ankle flexion movements during stepping than the RS group, as measured by the percentage of time the hind limb was either dragging or in withdrawal. The results from this study support the hypothesis that locomotor training consisting of FES timed to hind-limb movement improves the activation of hind-limb muscle more so than RS alone. Our rodent FES+RTT system can serve as a tool to help further develop this combined therapy to target appropriate neurophysiological changes for locomotor control.

  2. Bilateral flight muscle activity predicts wing kinematics and 3-dimensional body orientation of locusts responding to looming objects.

    Science.gov (United States)

    McMillan, Glyn A; Loessin, Vicky; Gray, John R

    2013-09-01

    We placed locusts in a wind tunnel using a loose tether design that allowed for motion in all three rotational degrees of freedom during presentation of a computer-generated looming disc. High-speed video allowed us to extract wing kinematics, abdomen position and 3-dimensional body orientation. Concurrent electromyographic (EMG) recordings monitored bilateral activity from the first basalar depressor muscles (m97) of the forewings, which are implicated in flight steering. Behavioural responses to a looming disc included cessation of flight (wings folded over the body), glides and active steering during sustained flight in addition to a decrease and increase in wingbeat frequency prior to and during, respectively, an evasive turn. Active steering involved shifts in bilateral m97 timing, wing asymmetries and whole-body rotations in the yaw (ψ), pitch (χ) and roll (η) planes. Changes in abdomen position and hindwing asymmetries occurred after turns were initiated. Forewing asymmetry and changes in η were most highly correlated with m97 spike latency. Correlations also increased as the disc approached, peaking prior to collision. On the inside of a turn, m97 spikes occurred earlier relative to forewing stroke reversal and bilateral timing corresponded to forewing asymmetry as well as changes in whole-body rotation. Double spikes in each m97 occurred most frequently at or immediately prior to the time the locusts turned, suggesting a behavioural significance. These data provide information on mechanisms underlying 3-dimensional flight manoeuvres and will be used to drive a closed loop flight simulator to study responses of motion-sensitive visual neurons during production of realistic behaviours.

  3. Accretion/Jet Activity and Narrow [O III] Kinematics in Young Radio Galaxies

    CERN Document Server

    Wu, Qingwen; Humphrey, Andrew

    2009-01-01

    We estimate black hole masses and Eddington ratios for a sample of 81 young radio galaxies (42 CSS +39 GPS). We find that the average black hole (BH) mass of these young radio galaxies is ~8.3, which is less than that of radio loud QSOs and low redshift radio galaxies. The CSS/GPS sources have relatively high Eddington ratios, with an average value of =-0.75, which are similar to those of narrow line Seyfert 1 galaxies (NLS1s). This suggests that young radio galaxies may not only be in the early stages of their radio activity, but also in the early stage of their accretion activity. We find that the young radio galaxies as a class deviate systematically from M_bh-\\sigma relation defined by nearby inactive galaxies, when using [O III] as a surrogate for stellar velocity dispersion, \\sigma_* . We also find that the deviation of the [O III] line width is correlated with the Eddington ratio and sources with Lbol/LEdd~1 have the largest deviations, which are similar to those of radio quiet QSOs/NLS1s (radio jets i...

  4. Effect of ski simulator training on kinematic and muscle activation of the lower extremities.

    Science.gov (United States)

    Moon, Jeheon; Koo, Dohoon; Kim, Kitae; Shin, Insik; Kim, Hyeyoung; Kim, Jinhae

    2015-08-01

    [Purpose] This study aimed to verify the effectiveness of an augmented reality-based ski simulator through analyzing the changes in movement patterns as well as the engagement of major muscles of the lower body. [Subjects] Seven subjects participated in the study. All were national team-level athletes studying at "K" Sports University in Korea who exhibited comparable performance levels and had no record of injuries in the preceding 6 months (Age 23.4 ± 3.8 years; Height 172.6 ± 12.1 cm; Weight 72.3 ± 16.2 kg; Experience 12.3 ± 4.8 years). [Methods] A reality-based ski simulator developed by a Korean manufacturer was used for the study. Three digital video cameras and a wireless electromyography system were used to perform 3-dimensional motion analysis and measure muscle activation level. [Results] Left hip angulation was found to increase as the frequency of the turns increased. Electromyography data revealed that the activation level of the quadriceps group's extension muscles and the biceps femoris group's flexing muscles had a crossing pattern. [Conclusion] Sustained training using an augmented reality-based ski simulator resulted in movements that extended the lower body joints, which is thought to contribute to increasing muscle fatigue.

  5. Three-dimensional kinematic analysis of active cervical spine motion by using a multifaceted marker device.

    Science.gov (United States)

    Tsunezuka, Hiroaki; Kato, Daishiro; Okada, Satru; Ishihara, Shunta; Shimada, Junichi

    2013-01-01

    Assessing cervical range of motion (CROM) is an important part of the clinical evaluation of patients with conditions such as whiplash syndrome. This study aimed to develop a convenient and accurate system involving multifaceted marker device (MMD)-based assessment of 3-dimensional (3D) dynamic coupled CROM and joint angular velocity. We used an infrared optical tracking system and our newly developed MMD that solved problems such as marker shielding and reflection angle associated with the optical tracking devices and enabled sequential and accurate analysis of the 3D dynamic movement of the polyaxial joint and other structurally complicated joints. The study included 30 asymptomatic young male volunteers (age, 22-27 years). The MMD consisted of 5 surfaces and 5 markers and was attached to the participant's forehead. We measured active CROM (axial rotation, flexion/extension, and lateral bending) and joint angular velocity by the MMD. The MMD was easy to use, safe for patients and operators, could be constructed economically, and generated accurate data such as dynamic coupled CROM and angular velocity.

  6. Ionized gas kinematics of galaxies in the CALIFA survey. I. Velocity fields, kinematic parameters of the dominant component, and presence of kinematically distinct gaseous systems

    NARCIS (Netherlands)

    García-Lorenzo, B.; Márquez, I.; Barrera-Ballesteros, J. K.; Masegosa, J.; Husemann, B.; Falcón-Barroso, J.; Lyubenova, M.; Sánchez, S. F.; Walcher, J.; Mast, D.; García-Benito, R.; Méndez-Abreu, J.; van de Ven, G.; Spekkens, K.; Holmes, L.; Monreal-Ibero, A.; del Olmo, A.; Ziegler, B.; Bland-Hawthorn, J.; Sánchez-Blázquez, P.; Iglesias-Páramo, J.; Aguerri, J. A. L.; Papaderos, P.; Gomes, J. M.; Marino, R. A.; González Delgado, R. M.; Cortijo-Ferrero, C.; López-Sánchez, A. R.; Bekeraitė, S.; Wisotzki, L.; Bomans, D.

    2015-01-01

    Context. Ionized gas kinematics provide important clues to the dynamical structure of galaxies and hold constraints to the processes driving their evolution. Aims: The motivation of this work is to provide an overall characterization of the kinematic behavior of the ionized gas of the galaxies inclu

  7. Decoupled Closed-Form Solution for Humanoid Lower Limb Kinematics

    Directory of Open Access Journals (Sweden)

    Alejandro Said

    2015-01-01

    Full Text Available This paper presents an explicit, omnidirectional, analytical, and decoupled closed-form solution for the lower limb kinematics of the humanoid robot NAO. The paper starts by decoupling the position and orientation analysis from the overall Denavit-Hartenberg (DH transformation matrices. Here, the joint activation sequence for the DH matrices is based on the geometry of a triangle. Furthermore, the implementation of a forward and a reversed kinematic analysis for the support and swing phase equations is developed to avoid matrix inversion. The allocation of constant transformations allows the position and orientation end-coordinate systems to be aligned with each other. Also, the redefinition of the DH transformations and the use of constraints allow decoupling the shared DOF between the legs and the torso. Finally, a geometric approach to avoid the singularities during the walking process is indicated. Numerical data is presented along with an experimental implementation to prove the validity of the analytical results.

  8. Constraints on the outer radius of the broad emission line region of active galactic nuclei

    CERN Document Server

    Landt, Hermine; Elvis, Martin; Karovska, Margarita

    2014-01-01

    Here we present observational evidence that the broad emission line region (BELR) of active galactic nuclei (AGN) generally has an outer boundary. This was already clear for sources with an obvious transition between the broad and narrow components of their emission lines. We show that the narrow component of the higher-order Paschen lines is absent in all sources, revealing a broad emission line profile with a broad, flat top. This indicates that the BELR is kinematically separate from the narrow emission line region. We use the virial theorem to estimate the BELR outer radius from the flat top width of the unblended profiles of the strongest Paschen lines, Pa alpha and Pa beta, and find that it scales with the ionising continuum luminosity roughly as expected from photoionisation theory. The value of the incident continuum photon flux resulting from this relationship corresponds to that required for dust sublimation. A flat-topped broad emission line profile is produced by both a spherical gas distribution ...

  9. Kinematic Analysis of Healthy Hips during Weight-Bearing Activities by 3D-to-2D Model-to-Image Registration Technique

    Directory of Open Access Journals (Sweden)

    Daisuke Hara

    2014-01-01

    Full Text Available Dynamic hip kinematics during weight-bearing activities were analyzed for six healthy subjects. Continuous X-ray images of gait, chair-rising, squatting, and twisting were taken using a flat panel X-ray detector. Digitally reconstructed radiographic images were used for 3D-to-2D model-to-image registration technique. The root-mean-square errors associated with tracking the pelvis and femur were less than 0.3 mm and 0.3° for translations and rotations. For gait, chair-rising, and squatting, the maximum hip flexion angles averaged 29.6°, 81.3°, and 102.4°, respectively. The pelvis was tilted anteriorly around 4.4° on average during full gait cycle. For chair-rising and squatting, the maximum absolute value of anterior/posterior pelvic tilt averaged 12.4°/11.7° and 10.7°/10.8°, respectively. Hip flexion peaked on the way of movement due to further anterior pelvic tilt during both chair-rising and squatting. For twisting, the maximum absolute value of hip internal/external rotation averaged 29.2°/30.7°. This study revealed activity dependent kinematics of healthy hip joints with coordinated pelvic and femoral dynamic movements. Kinematics’ data during activities of daily living may provide important insight as to the evaluating kinematics of pathological and reconstructed hips.

  10. Peak Muscle Activation, Joint Kinematics, and Kinetics during Elliptical and Stepping Movement Pattern on a Precor Adaptive Motion Trainer

    Science.gov (United States)

    Rogatzki, Matthew J.; Kernozek, Thomas W.; Willson, John D.; Greany, John F.; Hong, Di-An; Porcari, John P.

    2012-01-01

    Kinematic, kinetic, and electromyography data were collected from the biceps femoris, rectus femoris (RF), gluteus maximus, and erector spinae (ES) during a step and elliptical exercise at a standardized workload with no hand use. Findings depicted 95% greater ankle plantar flexion (p = 0.01), 29% more knee extension (p = 0.003), 101% higher peak…

  11. Evaluation of the Finis Swimsense® and the Garmin Swim™ activity monitors for swimming performance and stroke kinematics analysis

    Science.gov (United States)

    Mooney, Robert; Corley, Gavin; Godfrey, Alan; Osborough, Conor; ÓLaighin, Gearóid

    2017-01-01

    Aims The study aims were to evaluate the validity of two commercially available swimming activity monitors for quantifying temporal and kinematic swimming variables. Methods Ten national level swimmers (5 male, 5 female; 15.3±1.3years; 164.8±12.9cm; 62.4±11.1kg; 425±66 FINA points) completed a set protocol comprising 1,500m of swimming involving all four competitive swimming strokes. Swimmers wore the Finis Swimsense and the Garmin Swim activity monitors throughout. The devices automatically identified stroke type, swim distance, lap time, stroke count, stroke rate, stroke length and average speed. Video recordings were also obtained and used as a criterion measure to evaluate performance. Results A significant positive correlation was found between the monitors and video for the identification of each of the four swim strokes (Garmin: X2 (3) = 31.292, p<0.05; Finis:X2 (3) = 33.004, p<0.05). No significant differences were found for swim distance measurements. Swimming laps performed in the middle of a swimming interval showed no significant difference from the criterion (Garmin: bias -0.065, 95% confidence intervals -3.828–6.920; Finis bias -0.02, 95% confidence intervals -3.095–3.142). However laps performed at the beginning and end of an interval were not as accurately timed. Additionally, a statistical difference was found for stroke count measurements in all but two occasions (p<0.05). These differences affect the accuracy of stroke rate, stroke length and average speed scores reported by the monitors, as all of these are derived from lap times and stroke counts. Conclusions Both monitors were found to operate with a relatively similar performance level and appear suited for recreational use. However, issues with feature detection accuracy may be related to individual variances in stroke technique. It is reasonable to expect that this level of error would increase when the devices are used by recreational swimmers rather than elite swimmers. Further

  12. Are communication activities shaped by environmental constraints in reverberating and absorbing forest habitats?

    Directory of Open Access Journals (Sweden)

    Nicolas Manthevon

    2004-06-01

    Full Text Available In the dense vegetation of temperate or tropical forests, communication processes are constrained by propagation-induced modifications of the transmitted sounds. The presence of leaves, trunks and branches induces important sound reverberation and absorption leading to diminution of the signal energy as well as qualitative modifications. The aim of this paper is to briefly review the different strategies used by birds to manage with these constraints. At the emitter's level, an adapted emission behavior which takes into account both the physical heterogeneities of the forest environment and the temporal variations of the acoustic constraints, is especially useful to control the active space of signaling. The coding of information into acoustic parameters that have different susceptibility to propagation constraints is also of great interest. At the receiver's level, an adaptive reception behavior (listening post and a great tolerance to sound degradation during the decoding process are the keys to an optimal communication process.Na vegetação densa das florestas temperadas ou tropicais, os processos de comunicação são limitados pelas modificações dos sons durante sua propagação. A presença de folhas, troncos e galhos produz uma importante reverberação e absorção do som, provocando uma diminuição da energia do sinal, assim como modificações qualitativas. O objetivo deste artigo é de revisar brevemente as diferentes estratégias usadas por aves para gerenciar essas limitações. Para o emissor, um comportamento de emissão adaptado tanto às heterogeneidades físicas do meio florestal, quanto às variações temporais das exigências acústicas, é particularmente útil para controlar o canal ativo de sinalização. A codificação da informação em parâmetros acústicos com diferentes sensibilidades às exigências de propagação é também de grande valia. Para o receptor, um comportamento adaptado (posto de escuta e uma

  13. Parallel kinematics type, kinematics, and optimal design

    CERN Document Server

    Liu, Xin-Jun

    2014-01-01

    Parallel Kinematics- Type, Kinematics, and Optimal Design presents the results of 15 year's research on parallel mechanisms and parallel kinematics machines. This book covers the systematic classification of parallel mechanisms (PMs) as well as providing a large number of mechanical architectures of PMs available for use in practical applications. It focuses on the kinematic design of parallel robots. One successful application of parallel mechanisms in the field of machine tools, which is also called parallel kinematics machines, has been the emerging trend in advanced machine tools. The book describes not only the main aspects and important topics in parallel kinematics, but also references novel concepts and approaches, i.e. type synthesis based on evolution, performance evaluation and optimization based on screw theory, singularity model taking into account motion and force transmissibility, and others.   This book is intended for researchers, scientists, engineers and postgraduates or above with interes...

  14. The Origin of Double-peaked Narrow Lines in Active Galactic Nuclei II: Kinematic Classifications for the Population at z < 0.1

    CERN Document Server

    Nevin, Rebecca; Müller-Sánchez, Francisco; Barrows, R Scott; Cooper, Michael

    2016-01-01

    We present optical longslit observations of the complete sample of 71 Type 2 active galactic nuclei (AGNs) with double-peaked narrow emission lines at $z < 0.1$ in the Sloan Digital Sky Survey. Double-peaked emission lines are produced by a variety of mechanisms including disk rotation, kpc-scale dual AGNs, and NLR kinematics (outflows or inflows). We develop a novel kinematic classification technique to determine the nature of these objects using longslit spectroscopy alone. We determine that 86% of the double-peaked profiles are produced by moderate luminosity AGN outflows, 6% are produced by rotation, and 8% are ambiguous. While we are unable to directly identify dual AGNs with longslit data alone, we explore their potential kinematic classifications with this method. We also find a positive correlation between the narrow-line region (NLR) size and luminosity of the AGN NLRs (R$_{\\mathrm{NLR}}\\propto \\; {\\mathrm{L}_{\\mathrm{[OIII]}}}^{0.21 \\pm 0.05}$), indicating a clumpy two-zone ionization model for t...

  15. The Origin of Double-peaked Narrow Lines in Active Galactic Nuclei. II. Kinematic Classifications for the Population at z < 0.1

    Science.gov (United States)

    Nevin, R.; Comerford, J.; Müller-Sánchez, F.; Barrows, R.; Cooper, M.

    2016-11-01

    We present optical long-slit observations of the complete sample of 71 Type 2 active galactic nuclei (AGNs) with double-peaked narrow emission lines at z < 0.1 in the Sloan Digital Sky Survey. Double-peaked emission lines are produced by a variety of mechanisms including disk rotation, kiloparsec-scale dual AGNs, and narrow-line region (NLR) kinematics (outflows or inflows). We develop a novel kinematic classification technique to determine the nature of these objects using long-slit spectroscopy alone. We determine that 86% of the double-peaked profiles are produced by moderate-luminosity AGN outflows, 6% are produced by rotation, and 8% are ambiguous. While we are unable to directly identify dual AGNs with long-slit data alone, we explore their potential kinematic classifications with this method. We also find a positive correlation between the NLR size and luminosity of the AGN NLRs (R {}{NLR}\\propto {L}[{{O} {{III}}]}0.21+/- 0.05), indicating a clumpy two-zone ionization model for the NLR.

  16. Interactive inverse kinematics for human motion estimation

    DEFF Research Database (Denmark)

    Engell-Nørregård, Morten Pol; Hauberg, Søren; Lapuyade, Jerome

    2009-01-01

    We present an application of a fast interactive inverse kinematics method as a dimensionality reduction for monocular human motion estimation. The inverse kinematics solver deals efficiently and robustly with box constraints and does not suffer from shaking artifacts. The presented motion...... estimation system uses a single camera to estimate the motion of a human. The results show that inverse kinematics can significantly speed up the estimation process, while retaining a quality comparable to a full pose motion estimation system. Our novelty lies primarily in use of inverse kinematics...... to significantly speed up the particle filtering. It should be stressed that the observation part of the system has not been our focus, and as such is described only from a sense of completeness. With our approach it is possible to construct a robust and computationally efficient system for human motion estimation....

  17. 3D musculo-skeletal finite element analysis of the foot kinematics under muscle activation with and without ankle arthrodesis

    OpenAIRE

    Perrier, Antoine; Bucki, Marek; Luboz, Vincent; Vuillerme, Nicolas; Payan, Yohan

    2015-01-01

    International audience; The choice between arthrodesis and arthroplasty in the context of advanced ankle arthrosis remains a highly disputed topic in the field of foot and ankle surgery. Arthrodesis, however, represents the most popular option. Biomechanical modeling has been widely used to investigate static loading of cadaveric feet as well as consequences of arthrodesis on bony structures. Although foot kinematics has been studied using motion analysis, this approach lacks accuracy in capt...

  18. Binary Active Galactic Nuclei in Stripe 82: Constraints on Synchronized Black Hole Accretion in Major Mergers

    CERN Document Server

    Fu, Hai; Myers, A D; Djorgovski, S G; Yan, Lin

    2015-01-01

    Representing simultaneous black hole accretion during a merger, binary active galactic nuclei (AGNs) could provide valuable observational constraints to models of galaxy mergers and AGN triggering. High-resolution radio interferometer imaging offers a promising method to identify a large and uniform sample of binary AGNs, because it probes a generic feature of nuclear activity and is free from dust obscuration. Our previous search yielded 52 strong candidates of kpc-scale binaries over the 92 deg^2 of the Sloan Digital Sky Survey (SDSS) Stripe 82 area with 2"-resolution Very Large Array (VLA) images. Here we present 0.3"-resolution VLA 6 GHz observations for six candidates that have complete optical spectroscopy. The new data confirm the binary nature of four candidates and identify the other two as line-of-sight projections of radio structures from single AGNs. The four binary AGNs at z ~ 0.1 reside in major mergers with projected separations of 4.2-12 kpc. Optical spectral modeling shows that their hosts ha...

  19. Strong constraint on hadronic models of blazar activity from Fermi and IceCube stacking analysis

    CERN Document Server

    Neronov, A; Ptitsyna, K

    2016-01-01

    High-energy emission from blazars is produced by electrons which are either accelerated directly (the assumption of leptonic models of blazar activity) or produced in interactions of accelerated protons with matter and radiation fields (the assumption of hadronic models). The hadronic models predict that gamma-ray emission is accompanied by neutrino emission with comparable energy flux but with a different spectrum. We derive constraints on the hadronic models of activity of blazars imposed by non-detection of neutrino flux from a population of gamma-ray emitting blazars. We stack the gamma-ray and muon neutrino flux from 749 blazars situated in the declination strip above -5 degrees. Non-detection of neutrino flux from the stacked blazar sample rules out the proton induced cacade models in which the high-energy emission is powered by interactions of shock-accelerated proton beam in the AGN jet with the ambient matter or with the radiation field of the black hole accretion disk. The result remains valid also ...

  20. Vector bundle constraint for particle swarm optimization and its application to active contour modeling

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Active contour modeling (ACM) has been shown to be a powerful method in object boundary extraction. In this paper,a new ACM based on vector bundle constraint for particle swarm optimization (VBCPSO-ACM) is proposed. Different from the traditional.particle swarm optimization (PSO), in the process of velocity update, a vector bundle is predefined for each particle and velocity update of the particle is restricted to its bundle. Applying this idea to ACM, control points on the contour are treated as particles in PSO and the evolution of the contour is driven by the particles. Meanwhile, global searching is shifted to local searching in ACM by decreasing the number of neighbors and inertia. In addition, the addition and deletion of particles on the active contour make this new model possible for representing the real boundaries more precisely. The proposed VBCPSO-ACM can avoid self-intersection during contour evolving and also extract inhomogeneous boundaries. The simulation results proved its great performance in performing contour extraction.

  1. The Effects of Constraint-Induced Movement Therapy on Activities Important to Independent School Participation of Children with Hemiparesis

    Science.gov (United States)

    Carney, Joan

    2012-01-01

    This study investigated the efficacy of constraint-induced movement therapy (CI therapy) on activities important to school participation in children with hemiparesis. Four children, ages 4-0 to 7-10 participated in an intensive CI therapy program in a clinical setting. Constraining casts were worn 24 hours daily. Therapy was delivered 6 hours…

  2. JFKengine: A Jacobian and Forward Kinematics Generator

    Energy Technology Data Exchange (ETDEWEB)

    Fischer, K.N.

    2003-02-13

    During robot path planning and control the equations that describe the robot motions are determined and solved. Historically these expressions were derived analytically off-line. For robots that must adapt to their environment or perform a wide range of tasks, a way is needed to rapidly re-derive these expressions to take into account the robot kinematic changes, such as when a tool is added to the end-effector. The JFKengine software was developed to automatically produce the expressions representing the manipulator arm motion, including the manipulator arm Jacobian and the forward kinematic expressions. Its programming interface can be used in conjunction with robot simulation software or with robot control software. Thus, it helps to automate the process of configuration changes for serial robot manipulators. If the manipulator undergoes a geometric change, such as tool acquisition, then JFKengine can be invoked again from the control or simulation software, passing it parameters for the new arm configuration. This report describes the automated processes that are implemented by JFKengine to derive the kinematic equations and the programming interface by which it is invoked. Then it discusses the tree data structure that was chosen to store the expressions, followed by several examples of portions of expressions as represented in the tree. The C++ classes and their methods that implement the expression differentiation and evaluation operations are described. The algorithms used to construct the Jacobian and forward kinematic equations using these basic building blocks are then illustrated. The activity described in this report is part of a larger project entitled ''Multi-Optimization Criteria-Based Robot Behavioral Adaptability and Motion Planning'' that focuses on the development of a methodology for the generalized resolution of robot motion equations with time-varying configurations, constraints, and task objective criteria. A specific

  3. Kinematics, Dynamics, and the Structure of Physical Theory

    CERN Document Server

    Curiel, Erik

    2016-01-01

    Every physical theory has (at least) two different forms of mathematical equations to represent its target systems: the dynamical (equations of motion) and the kinematical (kinematical constraints). Kinematical constraints are differentiated from equations of motion by the fact that their particular form is fixed once and for all, irrespective of the interactions the system enters into. By contrast, the particular form of a system's equations of motion depends essentially on the particular interaction the system enters into. All contemporary accounts of the structure and semantics of physical theory treat dynamics, i.e., the equations of motion, as the most important feature of a theory for the purposes of its philosophical analysis. I argue to the contrary that it is the kinematical constraints that determine the structure and empirical content of a physical theory in the most important ways: they function as necessary preconditions for the appropriate application of the theory; they differentiate types of p...

  4. The Effects of Unilateral Adaptation of Hearing Aids on Symptoms of Depression and Social Activity Constraints of Elderly

    OpenAIRE

    Santos, Fernanda Dutra dos; Teixeira, Adriane Ribeiro

    2014-01-01

    Introduction Hearing loss is one of the most common problems in the elderly population. Besides compromising oral communication, it directly affects social relations and prevents elderly patients from living actively in society, possibly leading to the onset of depression or other conditions. Objective To analyze the effects of unilateral adaptation of hearing aids on symptoms of depression and the social activity constraints of elderly subjects with hearing impairment. Methods The samp...

  5. The Effects of Unilateral Adaptation of Hearing Aids on Symptoms of Depression and Social Activity Constraints of Elderly

    Directory of Open Access Journals (Sweden)

    Santos, Fernanda Dutra dos

    2015-01-01

    Full Text Available Introduction Hearing loss is one of the most common problems in the elderly population. Besides compromising oral communication, it directly affects social relations and prevents elderly patients from living actively in society, possibly leading to the onset of depression or other conditions. Objective To analyze the effects of unilateral adaptation of hearing aids on symptoms of depression and the social activity constraints of elderly subjects with hearing impairment. Methods The sample consisted of elderly subjects with hearing loss who did not use hearing aids. Data were collected in two phases. Initially, all participants underwent an audiological assessment and answered the Hearing Handicap Inventory for Elderly (summarized version and the Geriatric Depression Scale. All subjects participated in the selection and hearing aid adaptation processes and became monaural hearing aid users. After 30 days of hearing aid use, they were assessed with the same instruments. The results of the questionnaires before and after hearing aid adaptation were compared. Results The sample consisted of 13 individuals, between 60 and 90 years old (mean 72.85 ± 11.05 years. Data analysis showed that there was significant improvement in social activity constraints (p < 0.001 and in symptoms of depression (p = 0.031. Conclusion Results show that, in the sample studied, unilateral hearing aid adaptation reduced social activity constraints and depression symptoms.

  6. The Effects of Unilateral Adaptation of Hearing Aids on Symptoms of Depression and Social Activity Constraints of Elderly.

    Science.gov (United States)

    Santos, Fernanda Dutra Dos; Teixeira, Adriane Ribeiro

    2015-07-01

    Introduction Hearing loss is one of the most common problems in the elderly population. Besides compromising oral communication, it directly affects social relations and prevents elderly patients from living actively in society, possibly leading to the onset of depression or other conditions. Objective To analyze the effects of unilateral adaptation of hearing aids on symptoms of depression and the social activity constraints of elderly subjects with hearing impairment. Methods The sample consisted of elderly subjects with hearing loss who did not use hearing aids. Data were collected in two phases. Initially, all participants underwent an audiological assessment and answered the Hearing Handicap Inventory for Elderly (summarized version) and the Geriatric Depression Scale. All subjects participated in the selection and hearing aid adaptation processes and became monaural hearing aid users. After 30 days of hearing aid use, they were assessed with the same instruments. The results of the questionnaires before and after hearing aid adaptation were compared. Results The sample consisted of 13 individuals, between 60 and 90 years old (mean 72.85 ± 11.05 years). Data analysis showed that there was significant improvement in social activity constraints (p depression (p = 0.031). Conclusion Results show that, in the sample studied, unilateral hearing aid adaptation reduced social activity constraints and depression symptoms.

  7. MOJAVE: Monitoring of Jets in Active Galactic Nuclei with VLBA Experiments. VI. Kinematics Analysis of a Complete Sample of Blazar Jets

    CERN Document Server

    Lister, M L; Homan, D C; Kadler, M; Kellermann, K I; Kovalev, Y Y; Ros, E; Savolainen, T; Zensus, J A

    2009-01-01

    We discuss the jet kinematics of a complete flux-density-limited sample of 135 radio-loud active galactic nuclei (AGN) resulting from a 13 year program to investigate the structure and evolution of parsec-scale jet phenomena. Our analysis is based on new 2 cm Very Long Baseline Array (VLBA) images obtained between 2002 and 2007, but includes our previously published observations made at the same wavelength, and is supplemented by VLBA archive data. In all, we have used 2424 images spanning the years 1994-2007 to study and determine the motions of 526 separate jet features in 127 jets. The data quality and temporal coverage (a median of 15 epochs per source) of this complete AGN jet sample represents a significant advance over previous kinematics surveys. In all but five AGNs, the jets appear one-sided, most likely the result of differential Doppler boosting. In general the observed motions are directed along the jet ridge line, outward from the optically thick core feature. We directly observe changes in spee...

  8. Are communication activities shaped by environmental constraints in reverberating and absorbing forest habitats?

    DEFF Research Database (Denmark)

    Mathevon, Nicolas; Aubin, Thierry; Dabelsteen, Torben

    2004-01-01

    energy as well as qualitative modifications. The aim of this paper is to briefly review the different strategies used by birds to manage with these constraints. At the emitter’s level, an adapted emission behavior which takes into account both the physical heterogeneities of the forest environment...

  9. Kinematically Detected Halo Streams

    CERN Document Server

    Smith, Martin C

    2016-01-01

    Clues to the origins and evolution of our Galaxy can be found in the kinematics of stars around us. Remnants of accreted satellite galaxies produce over- densities in velocity-space, which can remain coherent for much longer than spatial over-densities. This chapter reviews a number of studies that have hunted for these accretion relics, both in the nearby solar-neighborhood and the more-distant stellar halo. Many observational surveys have driven this field forwards, from early work with the Hipparcos mission, to contemporary surveys like RAVE & SDSS. This active field continues to flourish, providing many new discoveries, and will be revolutionised as the Gaia mission delivers precise proper motions for a billion stars in our Galaxy.

  10. Inverse Kinematics of Concentric Tube Steerable Needles

    Science.gov (United States)

    Sears, Patrick; Dupont, Pierre E.

    2013-01-01

    Prior papers have introduced steerable needles composed of precurved concentric tubes. The curvature and extent of these needles can be controlled by the relative rotation and translation of the individual tubes. Under certain assumptions on the geometry and design of these needles, the forward kinematics problem can be solved in closed form by means of algebraic equations. The inverse kinematics problem, however, is not as straightforward owing to the nonlinear map between relative tube displacements and needle tip configuration as well as to the multiplicity of solutions as the number of tubes increases. This paper presents a general approach to solving the inverse kinematics problem using a pseudoinverse solution together with gradients of nullspace potential functions to enforce geometric and mechanical constraints. PMID:23685532

  11. Scheduling a maintenance activity under skills constraints to minimize total weighted tardiness and late tasks

    Directory of Open Access Journals (Sweden)

    Djalal Hedjazi

    2015-04-01

    Full Text Available Skill management is a key factor in improving effectiveness of industrial companies, notably their maintenance services. The problem considered in this paper concerns scheduling of maintenance tasks under resource (maintenance teams constraints. This problem is generally known as unrelated parallel machine scheduling. We consider the problem with a both objectives of minimizing total weighted tardiness (TWT and number of tardiness tasks. Our interest is focused particularly on solving this problem under skill constraints, which each resource has a skill level. So, we propose a new efficient heuristic to obtain an approximate solution for this NP-hard problem and demonstrate his effectiveness through computational experiments. This heuristic is designed for implementation in a static maintenance scheduling problem (with unequal release dates, processing times and resource skills, while minimizing objective functions aforementioned.

  12. Efficient human hand kinematics for manipulation tasks

    OpenAIRE

    Cobos Guzmán, Salvador; Ferre Perez, Manuel; Sanchez-Uran Gonzalez, Miguel Angel; Ortego la Moneda, Javier; Peña, César

    2008-01-01

    This work is focused on obtaining efficient human hand models that are suitable for manipulation tasks. A 24 DoF kinematic model of the human hand is defined to realistic movements. This model is based on the human skeleton. Dynamic and Static constraints have been included in order to improve the movement realism. Two simplified hand models with 9 and 6 DoF have been developed according to the constraints predefined. These simplified models involve some errors in reconstructing the hand post...

  13. EFFECT OF POSTURAL CORRECTION WITH DIFFERENT TAPING MATERIALS ON SCAPULAR KINEMATICS AND MYOELECTRIC ACTIVITIES OF SCAPULAR ROTATORS IN SUBACROMIAL IMPINGEMENT SYNDROME A RANDOMIZED PLACEBO-CONTROLLED TRIAL

    Directory of Open Access Journals (Sweden)

    Eman Mohamad Abd Al-Gawad

    2016-06-01

    Full Text Available Background: Rigid and kinesio tapings are commonly used in the rehabilitation of subacromial impingement syndrome (SIS. Yet; the effect of postural correction with the two taping materials in SIS has not been extensively studied. The purpose of the study is to examine the effect of postural correction with two different taping materials on scapular kinematics and electromyography of scapular upward rotators in patients with SIS. Methods: Twenty female patients with SIS participated in this study. Their age ranged from 30-60 years. Participants were randomly assigned into: Group I (Kinesio tape, n=10 and Group II (rigid tape, n=10. Thoracic and scapular taping with posture correction was applied to both groups. Scapular upward rotation at 0˚, 60˚, 90˚ and 120˚ of shoulder elevation and the activity level of the upper fibers of trapezius (UT, lower fibers of trapezius (LT and serratus anterior (SA muscles were measured before and immediately after taping application. Results: Both taping materials significantly increased scapular upward rotation at 60°, 90° and 120° angles (P =.004,.002 and .047 respectively after the application of tape as compared to the before. In addition, significantly greater muscle activity of the LT and SA muscles (P =.027 and 0.05 respectively were demonstrated by the kinesio-taping group as compared to rigid taping group during real taping condition. Conclusion: Both taping materials are effective in restoring scapular kinematics. Furthermore, kinesio taping has a facilitatory effect on the LT and SA muscles. Kinesio taping may be considered an alternative to rigid taping in patients with SIS.

  14. Kinematics of syn- and post-exhumational shear zones at Lago di Cignana (Western Alps, Italy): constraints on the exhumation of Zermatt-Saas (ultra)high-pressure rocks and deformation along the Combin Fault and Dent Blanche Basal Thrust

    Science.gov (United States)

    Kirst, Frederik; Leiss, Bernd

    2017-01-01

    Kinematic analyses of shear zones at Lago di Cignana in the Italian Western Alps were used to constrain the structural evolution of units from the Piemont-Ligurian oceanic realm (Zermatt-Saas and Combin zones) and the Adriatic continental margin (Dent Blanche nappe) during Palaeogene syn- and post-exhumational deformation. Exhumation of Zermatt-Saas (U)HP rocks to approximately lower crustal levels at ca. 39 Ma occurred during normal-sense top-(S)E shearing under epidote-amphibolite-facies conditions. Juxtaposition with the overlying Combin zone along the Combin Fault at mid-crustal levels occurred during greenschist-facies normal-sense top-SE shearing at ca. 38 Ma. The scarcity of top-SE kinematic indicators in the hanging wall of the Combin Fault probably resulted from strain localization along the uppermost Zermatt-Saas zone and obliteration by subsequent deformation. A phase of dominant pure shear deformation around 35 Ma affected units in the direct footwall and hanging wall of the Combin Fault. It is interpreted to reflect NW-SE crustal elongation during updoming of the nappe stack as a result of underthrusting of European continental margin units and the onset of continental collision. This phase was partly accompanied and followed by ductile bulk top-NW shearing, especially at higher structural levels, which transitioned into semi-ductile to brittle normal-sense top-NW deformation due to Vanzone phase folding from ca. 32 Ma onwards. Our structural observations suggest that syn-exhumational deformation is partly preserved within units and shear zones exposed at Lago di Cignana but also that the Combin Fault and Dent Blanche Basal Thrust experienced significant post-exhumational deformation reworking and overprinting earlier structures.

  15. Global-local optimization of flapping kinematics in hovering flight

    KAUST Repository

    Ghommem, Mehdi

    2013-06-01

    The kinematics of a hovering wing are optimized by combining the 2-d unsteady vortex lattice method with a hybrid of global and local optimization algorithms. The objective is to minimize the required aerodynamic power under a lift constraint. The hybrid optimization is used to efficiently navigate the complex design space due to wing-wake interference present in hovering aerodynamics. The flapping wing is chosen so that its chord length and flapping frequency match the morphological and flight properties of two insects with different masses. The results suggest that imposing a delay between the different oscillatory motions defining the flapping kinematics, and controlling the way through which the wing rotates at the end of each half stroke can improve aerodynamic power under a lift constraint. Furthermore, our optimization analysis identified optimal kinematics that agree fairly well with observed insect kinematics, as well as previously published numerical results.

  16. Influence of gravity compensation on kinematics and muscle activation patterns during reach and retrieval in subjects with cervical spinal cord injury: an explorative study.

    Science.gov (United States)

    Kloosterman, Marieke G M; Snoek, Govert J; Kouwenhoven, Mirjam; Nene, Anand V; Jannink, Michiel J A

    2010-01-01

    Many interventions in upper-limb rehabilitation after cervical spinal cord injury (CSCI) use arm support (gravity compensation); however, its specific effects on kinematics and muscle activation characteristics in subjects with a CSCI are largely unknown. We conducted a cross-sectional explorative study to study these effects. Nine subjects with a CSCI performed two goal-directed arm movements (maximal reach, reach and retrieval) with and without gravity compensation. Angles at elbow and shoulder joints and muscle activation were measured and compared. Seven subjects reduced elbow extension (range 1.8°-4.5°) during the maximal reaching task with gravity compensation. In the reach and retrieval task with gravity compensation, all subjects decreased elbow extension (range 0.1°-11.0°). Eight subjects executed movement closer to the body. Regarding muscle activation, gravity compensation did not influence timing; however, the amplitude of activation decreased, especially in antigravity muscles, namely mean change +/- standard deviation of descending part of trapezius (18.2% +/- 37.5%), anterior part of deltoid (37.7% +/- 16.7%), posterior part of deltoid (32.0% +/- 13.9%), and long head biceps (49.6% +/- 20.0%). Clinical implications for the use of gravity compensation in rehabilitation (during activities of daily living or exercise therapy) should be further investigated with a larger population.

  17. Kinematic Space and Wormholes

    CERN Document Server

    Zhang, Jian-dong

    2016-01-01

    The kinematic space could play a key role in constructing the bulk geometry from dual CFT. In this paper, we study the kinematic space from geometric points of view, without resorting to differential entropy. We find that the kinematic space could be intrinsically defined in the embedding space. For each oriented geodesic in the Poincar\\'e disk, there is a corresponding point in the kinematic space. This point is the tip of the causal diamond of the disk whose intersection with the Poincar\\'e disk determines the geodesic. In this geometric construction, the causal structure in the kinematic space can be seen clearly. Moreover, we find that every transformation in the $SL(2,\\mathbb{R})$ leads to a geodesic in the kinematic space. In particular, for a hyperbolic transformation defining a BTZ black hole, it is a timelike geodesic in the kinematic space. We show that the horizon length of the static BTZ black hole could be computed by the geodesic length of corresponding points in the kinematic space. Furthermore...

  18. Kinematic Analysis and Experimental Verification on the Locomotion of Gecko

    Institute of Scientific and Technical Information of China (English)

    Woochul Nam; TaeWon Seo; Byungwook Kim; Dongsu Jeon; Kyu-Jin Cho; Jongwon Kim

    2009-01-01

    This paper presents a kinematic analysis of the locomotion of a gecko, and experimental verification of the kinematic model. Kinematic analysis is important for parameter design, dynamic analysis, and optimization in biomimetic robot research. The proposed kinematic analysis can simulate, without iteration, the locomotion of gecko satisfying the constraint conditions that maintain the position of the contacted feet on the surface. So the method has an advantage for analyzing the climbing motion of the quadruped mechanism in a real time application. The kinematic model of a gecko consists of four legs based on 7-degrees of freedom spherical-revolute-spherical joints and two revolute joints in the waist. The motion of the kinematic model is simulated based on measurement data of each joint. The motion of the kinematic model simulates the investigated real gecko's motion by using the experimental results. The analysis solves the forward kinematics by considering the model as a combination of closed and open serial mechanisms under the condition that maintains the contact positions of the attached feet on the ground. The motions of each joint are validated by comparing with the experimental results. In addition to the measured gait, three other gaits are simulated based on the kinematic model. The maximum strides of each gait are calculated by workspace analysis. The result can be used in biomimetic robot design and motion planning.

  19. New GPS constraints on active deformation along the Africa-Iberia plate boundary

    Science.gov (United States)

    Koulali, A.; Ouazar, D.; Tahayt, A.; King, R. W.; Vernant, P.; Reilinger, R. E.; McClusky, S.; Mourabit, T.; Davila, J. M.; Amraoui, N.

    2011-08-01

    We use velocities from 65 continuous stations and 31 survey-mode GPS sites as well as kinematic modeling to investigate present day deformation along the Africa-Iberia plate boundary zone in the western Mediterranean region. The GPS velocity field shows southwestward motion of the central part of the Rif Mountains in northern Morocco with respect to Africa varying between 3.5 and 4.0 mm/yr, consistent with prior published results. Stations in the southwestern part of the Betic Mountains of southern Spain move west-southwest with respect to Eurasia (˜ 2-3 mm/yr). The western component of Betics motion is consistent with partial transfer of Nubia-Eurasia plate motion into the southern Betics. The southward component of Betics motion with respect to Iberia is kinematically consistent with south to southwest motion of the Rif Mountains with respect to Africa. We use block modeling, constrained by mapped surface faults and seismicity to estimate the geometry and rates of strain accumulation on plate boundary structures. Our preferred plate boundary geometry includes one block between Iberia and Africa including the SW Betics, Alboran Sea, and central Rif. This geometry provides a good fit to the observed motions, suggesting a wide transpressive boundary in the westernmost Mediterranean, with deformation mainly accommodated by the Gloria-Azores fault system to the West and the Rif-Tell lineament to the East. Block boundaries encompass aspects of earlier interpretations suggesting three main deformation styles: (i) extension along the NE-SW trending Trans-Alboran shear zone, (ii) dextral strike-slip in the Betics corresponding to a well defined E-W seismic lineament, and (iii) right lateral strike-slip motion extending West to the Azores and right-lateral motion with compression extending East along the Algerian Tell. We interpret differential motion in the Rif-Alboran-Betic system to be driven both by surface processes related the Africa-Eurasia oblique convergence and

  20. Inclusive distributions near kinematic thresholds

    CERN Document Server

    Gardi, E

    2006-01-01

    The main challenge in computing inclusive cross sections and decay spectra in QCD is posed by kinematic thresholds. The threshold region is characterized by stringent phase-space constraints that are reflected in large perturbative corrections due to soft and collinear radiation as well as large non-perturbative effects. Major progress in addressing this problem was made in recent years by Dressed Gluon Exponentiation (DGE), a formalism that combines Sudakov and renormalon resummation in moment space. DGE has proven effective in extending the range of applicability of perturbation theory well into the threshold region and in identifying the relevant non-perturbative corrections. Here we review the method from a general perspective using examples from deep inelastic structure functions, event-shape distributions, heavy-quark fragmentation and inclusive decay spectra. A special discussion is devoted to the applications of DGE to radiative and semileptonic B decays that have proven valuable for the interpretatio...

  1. Advances in robot kinematics

    CERN Document Server

    Khatib, Oussama

    2014-01-01

    The topics addressed in this book cover the whole range of kinematic analysis, synthesis and design and consider robotic systems possessing serial, parallel and cable driven mechanisms. The robotic systems range from being less than fully mobile to kinematically redundant to overconstrained.  The fifty-six contributions report the latest results in robot kinematics with emphasis on emerging areas such as design and control of humanoids or humanoid subsystems. The book is of interest to researchers wanting to bring their knowledge up to date regarding modern topics in one of the basic disciplines in robotics, which relates to the essential property of robots, the motion of mechanisms.

  2. Constraint Differentiation

    DEFF Research Database (Denmark)

    Mödersheim, Sebastian Alexander; Basin, David; Viganò, Luca

    2010-01-01

    , under the assumption that the original constraint-based approach has these properties. Practically, as a concrete case study, we have integrated this technique into OFMC, a state-of-the-art model-checker for security protocol analysis, and demonstrated its effectiveness by extensive experimentation. Our......We introduce constraint differentiation, a powerful technique for reducing search when model-checking security protocols using constraint-based methods. Constraint differentiation works by eliminating certain kinds of redundancies that arise in the search space when using constraints to represent...

  3. The influence of a semi-reclined seated posture on head and neck kinematics and muscle activity while reading a tablet computer.

    Science.gov (United States)

    Douglas, Ethan C; Gallagher, Kaitlin M

    2017-04-01

    Increased tablet computer usage calls for a proper understanding of potential injury risks from these devices. The purpose of this study was to assess the influence of tablet computer reading postures on head and neck flexion and muscle activity. Nineteen participants completed read a tablet computer in four different postures (standard computer monitor, tablet on a desk, tablet in the lap, semi-reclined with tablet in the lap). Reading the tablet in a semi-reclined trunk posture with the tablet in one's lap increased (p computer monitor (6.39%ROM). Head flexion in the semi-reclined posture (19.7%ROM) and muscle activity (8.88%MVC) were similar to when reading from a standard computer monitor. Despite potentially reducing the gravitational moment produced by the head, the semi-reclined position could still compromise the force capabilities of the neck extensor musculature and result in increased strain on the passive tissues of the spine. Future work should assess how the semi-reclined position influences cervical intervertebral angles and passive tissue properties of the cervical spine. Overall, more research needs to be conducted on thoracic spine kinematics while reading a tablet computer.

  4. America’s Cup Sailing: Effect of Standing Arm-Cranking (“Grinding” Direction on Muscle Activity, Kinematics, and Torque Application

    Directory of Open Access Journals (Sweden)

    Simon N. Pearson

    2016-06-01

    Full Text Available Grinding is a key physical element in America’s Cup sailing. This study aimed to describe kinematics and muscle activation patterns in relation to torque applied in forward and backward grinding. Ten male America’s Cup sailors (33.6 ± 5.7 years, 97.9 ± 13.4 kg, 186.6 ± 7.4 cm completed forward and backward grinding on a customised grinding ergometer. In forward grinding peak torque (77 Nm occurred at 95° (0° = crank vertically up on the downward section of the rotation at the end of shoulder flexion and elbow extension. Backward grinding torque peaked at 35° (69 Nm following the pull action (shoulder extension, elbow flexion across the top of the rotation. During forward grinding, relatively high levels of torque (>50 Nm were maintained through the majority (72% of the cycle, compared to 47% for backward grinding, with sections of low torque corresponding with low numbers of active muscles. Variation in torque was negatively associated with forward grinding performance (r = −0.60; 90% CI −0.88 to −0.02, but positively associated with backward performance (r = 0.48; CI = −0.15 to 0.83. Magnitude and distribution of torque generation differed according to grinding direction and presents an argument for divergent training methods to improve forward and backward grinding performance.

  5. A Constraint Embedding Approach for Complex Vehicle Suspension Dynamics

    Science.gov (United States)

    2015-04-24

    contains a number of articulated bodies with multiple kinematic closed loops. Despite the large number of internal degrees of freedom, due to the constraints, each suspension has only a single effective degree of freedom.

  6. Inverse Kinematics using Quaternions

    DEFF Research Database (Denmark)

    Henriksen, Knud; Erleben, Kenny; Engell-Nørregård, Morten

    In this project I describe the status of inverse kinematics research, with the focus firmly on the methods that solve the core problem. An overview of the different methods are presented Three common methods used in inverse kinematics computation have been chosen as subject for closer inspection....... suite, developed in this project and in [4]. Source code developed for this project includes the CCD method , improvements on the BFGS method and Jacobian inverse originally developed in [4]....

  7. Heat storage in Asian elephants during submaximal exercise: behavioral regulation of thermoregulatory constraints on activity in endothermic gigantotherms.

    Science.gov (United States)

    Rowe, M F; Bakken, G S; Ratliff, J J; Langman, V A

    2013-05-15

    Gigantic size presents both opportunities and challenges in thermoregulation. Allometric scaling relationships suggest that gigantic animals have difficulty dissipating metabolic heat. Large body size permits the maintenance of fairly constant core body temperatures in ectothermic animals by means of gigantothermy. Conversely, gigantothermy combined with endothermic metabolic rate and activity likely results in heat production rates that exceed heat loss rates. In tropical environments, it has been suggested that a substantial rate of heat storage might result in a potentially lethal rise in core body temperature in both elephants and endothermic dinosaurs. However, the behavioral choice of nocturnal activity might reduce heat storage. We sought to test the hypothesis that there is a functionally significant relationship between heat storage and locomotion in Asian elephants (Elephas maximus), and model the thermoregulatory constraints on activity in elephants and a similarly sized migratory dinosaur, Edmontosaurus. Pre- and post-exercise (N=37 trials) measurements of core body temperature and skin temperature, using thermography were made in two adult female Asian elephants at the Audubon Zoo in New Orleans, LA, USA. Over ambient air temperatures ranging from 8 to 34.5°C, when elephants exercised in full sun, ~56 to 100% of active metabolic heat production was stored in core body tissues. We estimate that during nocturnal activity, in the absence of solar radiation, between 5 and 64% of metabolic heat production would be stored in core tissues. Potentially lethal rates of heat storage in active elephants and Edmontosaurus could be behaviorally regulated by nocturnal activity.

  8. Atomic ionization by sterile-to-active neutrino conversion and constraints on dark matter sterile neutrinos with germanium detectors

    Science.gov (United States)

    Chen, Jiunn-Wei; Chi, Hsin-Chang; Lin, Shin-Ted; Liu, C.-P.; Singh, Lakhwinder; Wong, Henry T.; Wu, Chih-Liang; Wu, Chih-Pan

    2016-05-01

    The transition magnetic moment of a sterile neutrino can give rise to its conversion to an active neutrino through radiative decay or nonstandard interaction (NSI) with matter. For sterile neutrinos of keV-mass as dark matter candidates, their decay signals are actively searched for in cosmic x-ray spectra. In this work, we consider the NSI that leads to atomic ionization, which can be detected by direct dark matter experiments. It is found that this inelastic scattering process for a nonrelativistic sterile neutrino has a pronounced enhancement in the differential cross section at energy transfer about half of its mass, manifesting experimentally as peaks in the measurable energy spectra. The enhancement effects gradually smear out as the sterile neutrino becomes relativistic. Using data taken with low-threshold low-background germanium detectors, constraints on sterile neutrino mass and its transition magnetic moment are derived and compared with those from astrophysical observations.

  9. An Activity-Rotation Relationship and Kinematic Analysis of Nearby Mid-to-Late-type M Dwarfs

    CERN Document Server

    West, Andrew A; Irwin, Jonathan; Berta-Thompson, Zachory K; Charbonneau, David; Dittmann, Jason; Pineda, J Sebastian

    2015-01-01

    Using spectroscopic observations and photometric light curves of 238 nearby M dwarfs from the MEarth exoplanet transit survey, we examine the relationships between magnetic activity (quantified by H-alpha emission), rotation period, and stellar age. Previous attempts to investigate the relationship between magnetic activity and rotation in these stars were hampered by the limited number of M dwarfs with measured rotation periods (and the fact that vsini measurements probe only rapid rotation). However, the photometric data from MEarth allows us to probe a wide range of rotation periods for hundreds of M dwarf stars (from shorter than than one to longer than 100 days). Over all M spectral types that we probe, we find that the presence of magnetic activity is tied to rotation, including for late-type, fully convective M dwarfs. We also find evidence that the fraction of late-type M dwarfs that are active may be higher at longer rotation periods compared to their early-type counterparts, with several active, lat...

  10. Thermal and barometric constraints on the intrusive and unroofing history of the Black Mountains: Implications for timing, initial dip, and kinematics of detachment faulting in the Death Valley Region, California

    Science.gov (United States)

    Holm, Daniel K.; Snow, J. Kent; Lux, Daniel R.

    1992-06-01

    Unroofing of the Black Mountains, Death Valley, California, has resulted in the exposure of 1.7 Ga crystalline basement, late Precambrian amphibolite facies metasedimentary rocks, and a Tertiary magmatic complex. The 40Ar/39Ar cooling ages, obtained from samples collected across the entire length of the range (>55 km), combined with geobarometric results from synextensional intrusions, provide time-depth constraints on the Miocene intrusive history and extensional unroofing of the Black Mountains. Data from the southeastern Black Mountains and adjacent Greenwater Range suggest unroofing from shallow depths between 9 and 10 Ma. To the northwest in the crystalline core of the range, biotite plateau ages from ˜13 to 6.8 Ma from rocks making up the Death Valley turtlebacks indicate a midcrustal residence (with temperatures >300°C) prior to extensional unroofing. Biotite 40Ar/39Ar ages from both Precambrian basement and Tertiary plutons reveal a diachronous cooling pattern of decreasing ages toward the northwest, subparallel to the regional extension direction. Diachronous cooling was accompanied by dike intrusion which also decreases in age toward the northwest. The cooling age pattern and geobarometric constraints in crystalline rocks of the Black Mountains suggest denudation of 10-15 km along a northwest directed detachment system, consistent with regional reconstructions of Tertiary extension and with unroofing of a northwest deepening crustal section. Mica cooling ages that deviate from the northwest younging trend are consistent with northwestward transport of rocks initially at shallower crustal levels onto deeper levels along splays of the detachment. The well-known Amargosa chaos and perhaps the Badwater turtleback are examples of this "splaying" process. Considering the current distance of the structurally deepest samples away from moderately to steeply east tilted Tertiary strata in the southeastern Black Mountains, these data indicate an average initial

  11. A constrained generalised-α method for coupling rigid parallel chain kinematics and elastic bodies

    OpenAIRE

    Gransden, D.I.; Burkhard Bornemann, P.; Rose, M.; Nitzsche, F.

    2015-01-01

    A problem arises from combining flexible rotorcraft blades with stiffer mechanical links, which form a parallel kinematic chain. This paper introduces a method for solving index-3 differential algebraic equations for coupled stiff and elastic body systems with closed-loop kinematics. Rigid body dynamics and elastic body mechanics are independently described according to convenient mathematical measures. Holonomic constraint equations couple both the parallel chain kinematics and describe the ...

  12. Kinematic Fitting in the Presence of ISR at the ILC

    CERN Document Server

    List, Jenny; List, Benno

    2009-01-01

    Kinematic fitting is a well-established tool to improve jet energy and invariant mass resolutions by fitting the measured values under constraints (e.g. energy conservation). However, in the presence of substantial ISR and Beamstrahlung, naive energy and (longitudinal) momentum constraints fail due to the a priori unknown amount of undetected momentum carried away by collinear photons. It is possible to take care of those two effects and thus obtain significantly higher mass resolutions.

  13. The effects on Kinematics and Muscle Activity of Walking in a Robotic Gait Trainer During Zero-Force Control

    NARCIS (Netherlands)

    Asseldonk, van Edwin H.F.; Veneman, Jan F.; Ekkelenkamp, Ralf; Buurke, Jaap H.; Helm, van der Frans C.T.; Kooij, van der Herman

    2008-01-01

    “Assist as needed” control algorithms promote activity of patients during robotic gait training. Implementing these requires a free walking mode of a device, as unassisted motions should not be hindered. The goal of this study was to assess the normality of walking in the free walking mode of the LO

  14. Transition from collision to subduction in Western Greece: the Katouna-Stamna active fault system and regional kinematics

    Science.gov (United States)

    Pérouse, E.; Sébrier, M.; Braucher, R.; Chamot-Rooke, N.; Bourlès, D.; Briole, P.; Sorel, D.; Dimitrov, D.; Arsenikos, S.

    2016-06-01

    Transition from subduction to collision occurs in Western Greece and is accommodated along the downgoing plate by the Kefalonia right-lateral fault that transfers the Hellenic subduction front to the Apulian collision front. Here we present an active tectonic study of Aitolo-Akarnania (Western Greece) that highlights how such a transition is accommodated in the overriding plate. Based on new multi-scale geomorphic and tectonic observations, we performed an accurate active fault trace mapping in the region, and provide evidence for active normal and left-lateral faulting along the Katouna-Stamna Fault (KSF), a 65-km-long NNW-striking fault system connecting the Amvrakikos Gulf to the Patras Gulf. We further show that the Cenozoic Hellenide thrusts located west of the KSF are no longer active, either in field observation or in GPS data, leading us to propose that the KSF forms the northeastern boundary of a rigid Ionian Islands-Akarnania Block (IAB). Cosmic ray exposure measurements of 10Be and 36Cl were performed on a Quaternary alluvial fan offset along the KSF (~50 m left-lateral offset). A maximum abandonment age of ~12-14 ka for the alluvial fan surface can be determined, giving an estimated KSF minimum geological left-lateral slip rate of ~4 mm year-1, in agreement with high GPS slip rates (~10 mm year-1). Despite this high slip rate, the KSF is characterized by subdued morphological evidence of tectonic activity, a gypsum-breccia bedrock and a low level of seismicity, suggesting a dominantly creeping behavior for this fault. Finally, we discuss how the IAB appears to have been progressively individualized during the Pleistocene (younger than ~1.5 Ma).

  15. Planet Host Stars: Mass, Age and Kinematics

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    We determine the mass, age and kinematics of 51 extra-solar planet host stars. The results are then used to search for signs of connection of the data with metallicity and to investigate the population nature. We find that the increase in mean metallicity with stellar mass is similar to that in normal field stars, so it seems unsuitable to use this relation as a constraint on the theory of planet formation. The age and kinematic distributions seem to favour the metallicity of extra-solar planet host stars being initial. Although the kinematic data of these stars indicate their origin from two populations - the thin and the thick disks, kinematics may not help in the maintenance of the planet around the host. Stars with planets, brown dwarfs or stellar companions are sorted into three groups and re-investigated separately for their formation mechanism. The main results indicate that stars with M2 < 25MJ have [Fe/H] > -0.1 and a wide period range, but there are no other differences.Thus, there does not seem to be any physically distinguishable characteristics among the three star groups.

  16. A Tale of Two Narrow-Line Regions: Ionization, Kinematics, and Spectral Energy Distributions for a Local Pair of Merging Obscured Active Galaxies

    CERN Document Server

    Hainline, Kevin N; Chen, Chien-Ting; Carroll, Christopher M; Jones, Mackenzie L; Zervos, Alexandros S; Goulding, Andrew D

    2016-01-01

    We explore the gas ionization and kinematics, as well as the optical--IR spectral energy distributions for UGC 11185, a nearby pair of merging galaxies hosting obscured active galactic nuclei (AGNs), also known as SDSS J181611.72+423941.6 and J181609.37+423923.0 (J1816NE and J1816SW, $z \\approx 0.04$). Due to the wide separation between these interacting galaxies ($\\sim 23$ kpc), observations of these objects provide a rare glimpse of the concurrent growth of supermassive black holes at an early merger stage. We use BPT line diagnostics to show that the full extent of the narrow line emission in both galaxies is photoionized by an AGN and confirm the existence of a 10-kpc-scale ionization cone in J1816NE, while in J1816SW the AGN narrow-line region is much more compact (1--2 kpc) and relatively undisturbed. Our observations also reveal the presence of ionized gas that nearly spans the entire distance between the galaxies which is likely in a merger-induced tidal stream. In addition, we carry out a spectral an...

  17. New seismotectonic constraints in the Western Pyrenees: regional activity and aftershock series monitoring.

    Science.gov (United States)

    Ruiz, M.; Gallart, J.; Díaz, J.; González-Cortina, J. M.; Pulgar, J. A.; López, C.

    2003-04-01

    New seismic data from a portable network deployed at the western end of the Pyrenean range reveal a moderate magnitude seismicity, till now poorly constrained by the present-day permanent networks monitoring the area. The westward continuity of the E-W band of seismicity associated to the North Pyrenean Fault, through the Basque Massifs along the Nappe des Marbres, ending up at the Hendaye fault is depicted from our data. This seismicity belt is distributed on a crustal scale, dipping northward to almost 30 km depth. Other groups of seismic events can be related to the southern segment of the Pamplona fault, and to different E-W thrust structures. Following a magnitude 4.1 earthquake on February 21, 2001 SW of Pamplona, another deployment was performed to study the aftershocks series. First determinations showed a small epicentral area of about 4 km2, with events distributed between 1 and 4 km depth. Cross-correlation techniques and relative location of events clusters constrained an epicentral domain 2 Km long and 500m wide, NNO-SSE oriented following the Arakil river course. Focal mechanisms favour an oblique normal fault, with a marked strike-slip component. A new relationship between local magnitude, epicentral distance and total signal duration of the analysed earthquakes was established and used to obtain a value of 0.80 for the b-parameter of the Gutemberg-Richter's law. Distribution of aftershocks magnitudes with time follows the typical power law and gives a value of 1.0 for the Omori's P-parameter. More than 100 aftershocks were accurately located in this high-resolution experiment, 17 of which could only be catalogued by the permanent agencies in the same period, with a much sparser distribution. Our results confirm the importance of using dense portable networks to infer relevant seismotectonic and hazard constraints.

  18. Mass transfer constraints on the chemical evolution of an active hydrothermal system, Valles caldera, New Mexico

    Science.gov (United States)

    White, A.F.; Chuma, N.J.; Goff, F.

    1992-01-01

    Partial equilibrium conditions occur between fluids and secondary minerals in the Valles hydrothermal system, contained principally in the Tertiary rhyolitic Bandelier Tuff. The mass transfer processes are governed by reactive phase compositions, surface areas, water-rock ratios, reaction rates, and fluid residence times. Experimental dissolution of the vitric phase of the tuff was congruent with respect to Cl in the solid and produced reaction rates which obeyed a general Arrhenius release rate between 250 and 300??C. The 18O differences between reacted and unreacted rock and fluids, and mass balances calculations involving Cl in the glass phase, produced comparable water-rock ratios of unity, confirming the importance of irreversible reaction of the vitric tuff. A fluid residence time of approximately 2 ?? 103 years, determined from fluid reservoir volume and discharge rates, is less than 0.2% of the total age of the hydrothermal system and denotes a geochemically and isotopically open system. Mass transfer calculations generally replicated observed reservoir pH, Pco2, and PO2 conditions, cation concentrations, and the secondary mineral assemblage between 250 and 300??C. The only extraneous component required to maintain observed calcite saturation and high Pco2 pressures was carbon presumably derived from underlying Paleozoic limestones. Phase rule constraints indicate that Cl was the only incompatible aqueous component not controlled by mineral equilibrium. Concentrations of Cl in the reservoir directly reflect mass transport rates as evidenced by correlations between anomalously high Cl concentrations in the fluids and tuff in the Valles caldera relative to other hydrothermal systems in rhyolitic rocks. ?? 1992.

  19. Decoupling Kinematic Loops for Real-Time Multibody Dynamic Simulations

    Directory of Open Access Journals (Sweden)

    Omar Mohamed

    2016-01-01

    Full Text Available Earth moving equipment are typically equipped with hydraulic cylinder actuators to perform the designated tasks. Multibody modelling of such systems results in models with kinematic loops that couples the motion variables of the loop bodies. Iterative solutions will be needed to satisfy the loop constraints and the applied constraints, which require evaluation of the constraint Jacobean matrix. The size of the Jacobean matrix and the associated projections depends on the number of motion variables in each kinematic loop. Consequently, the computational cost significantly increases as the number of variables in the kinematic loop increases. Real-time control and hybrid hardware-in-the-loop systems both require efficient and fast computational algorithms. Eliminating the kinematic loops can improve the computational efficiency and effectiveness of the control algorithms. This paper presents an efficient approach to eliminate the coupling due to the cylinder-rod connections and consequently the kinematic loops in the multibody models leading to efficient simulation. The proposed approach calculates the spatial accelerations and inertia forces of the actuator bodies and the interaction forces with other components. The actuator forces are then projected onto the connecting bodies leading to exact dynamics of the system.

  20. Recognition of Kinematic Joints of 3D Assembly Models Based on Reciprocal Screw Theory

    Directory of Open Access Journals (Sweden)

    Tao Xiong

    2016-01-01

    Full Text Available Reciprocal screw theory is used to recognize the kinematic joints of assemblies restricted by arbitrary combinations of geometry constraints. Kinematic analysis is common for reaching a satisfactory design. If a machine is large and the incidence of redesign frequent is high, then it becomes imperative to have fast analysis-redesign-reanalysis cycles. This work addresses this problem by providing recognition technology for converting a 3D assembly model into a kinematic joint model, which is represented by a graph of parts with kinematic joints among them. The three basic components of the geometric constraints are described in terms of wrench, and it is thus easy to model each common assembly constraint. At the same time, several different types of kinematic joints in practice are presented in terms of twist. For the reciprocal product of a twist and wrench, which is equal to zero, the geometry constraints can be converted into the corresponding kinematic joints as a result. To eliminate completely the redundant components of different geometry constraints that act upon the same part, the specific operation of a matrix space is applied. This ability is useful in supporting the kinematic design of properly constrained assemblies in CAD systems.

  1. Choice set formation with multiple flexible activities under space-time constraints

    NARCIS (Netherlands)

    Chen, X.; Kwan, M.P.

    2012-01-01

    In classical time geography, an individual travel path is composed of a chain of visits, with each visit being a flexible activity between two fixed activities at two known stations. In reality, individuals tend to carry out trips with much variation and complexity, with multipurpose trips being a p

  2. Int\\'egration de contraintes cin\\'ematiques pour le calcul de l'orientation optimis\\'ee de l'axe de l'outil en usinage 5 axes Optimisation of tool axis orientation in 5 axis machining taking into account kinematical constraints

    CERN Document Server

    Lavernhe, Sylvain; Lartigue, Claire; 10.1051/meca:2007064

    2010-01-01

    Apr\\`es avoir d\\'etaill\\'e les principales difficult\\'es li\\'ees \\`a l'usinage 5 axes UGV, nous pr\\'esentons un mod\\`ele de repr\\'esentation des trajectoires 5 axes sous forme surfacique permettant de prendre en compte des contraintes g\\'eom\\'etriques et cin\\'ematiques. Ce mod\\`ele est int\\'egr\\'e dans d'optimisation des trajets 5 axes afin de maximiser la productivit\\'e tout en garantissant la qualit\\'e g\\'eom\\'etrique attendue. Un cas d'application est d\\'etaill\\'e, illustrant la modification de l'orientation de l'axe de l'outil afin d'am\\'eliorer le comportement cin\\'ematique des axes lors du suivi des trajectoires. After presenting the main difficulties related to machining 5 axes machining within the context of HSM, we present a surface model of 5-axis trajectories allowing taking into account geometrical and kinematical constraints. This model is integrated in an optimization scheme in order to maximize the productivity while ensuring the expected geometrical quality. A case of application is detailed, ...

  3. Volunteer kinematics and reaction in lateral emergency maneuver tests

    NARCIS (Netherlands)

    Rooij, L. van; Elrofai, H.B.H.; Philippens, M.M.G.M.; Daanen, H.A.M.

    2013-01-01

    It is important to understand human kinematics and muscle activation patterns in emergency maneuvers for the design of safety systems and for the further development of human models. The objective of this study was to quantify kinematic behavior and muscle activation in simulated steering tests in s

  4. Nucleosynthesis constraints on active-sterile neutrino conversions in the early universe with random magnetic field

    CERN Document Server

    Semikoz, V B

    1994-01-01

    We consider active-sterile neutrino conversions in the early universe hot plasma in the presence of a random magnetic field generated at the electroweak phase transition. Within a random field domain the magnetization asymmetry of the lepton antilepton plasma produced by a uniform constant magnetic field is huge in contrast to their small density asymmetry, leading to a drastic change in the active-sterile conversion rates. Assuming that the random field provides the seed for the galactic field one can estimate the restrictions from primordial nucleosynthesis. Requiring that the extra sterile \

  5. The winter day as a constraint for human activity in Western Europe

    CERN Document Server

    Martín-Olalla, José-María

    2016-01-01

    Time use surveys in Denmark, Spain, France, Ireland, Italy and United Kingdom are analyzed to provide start, noon and end times for the main activities of a society: labor (the focus of this preprint), sleeping and eating. Also, the location at home is analyzed. Local times are converted into mean solar times and compared to latitude. Observed trends allow to unveil the winter day as a restriction for the human activity. Alternatively, apparently large time differences set forth by clocks, becomes smaller when observed as a time distance to winter sunrise or sunset.

  6. The Modular Robots Kinematics

    Directory of Open Access Journals (Sweden)

    Claudiu Pozna

    2007-08-01

    Full Text Available The present paper intention is to develop a kinematical foundation for our nextworks in industrial robots (IR modular design. The goal of this works is todevelop cheap and improved robots which are adapted to the costumer needs. Inorder to achieve the mentioned goal, in [43], we have started a bibliographicalresearch of the main modular design aspects. The mentioned analyze of the actualresults in modular robots design gives us the possibility to establish our researchprogram. The idea of this paper is to develop a kinematical formalism which willbe use in the next dedicated to this subject.

  7. Ventricular activity cancellation in electrograms during atrial fibrillation with constraints on residuals' power.

    Science.gov (United States)

    Corino, Valentina D A; Rivolta, Massimo W; Sassi, Roberto; Lombardi, Federico; Mainardi, Luca T

    2013-12-01

    During atrial fibrillation (AF), cancellation of ventricular activity from atrial electrograms (AEG) is commonly performed by template matching and subtraction (TMS): a running template, built in correspondence of QRSs, is subtracted from the AEG to uncover atrial activity (AA). However, TMS can produce poor cancellation, leaving high-power residues. In this study, we propose to modulate the templates before subtraction, in order to make the residuals as similar as possible to the nearby atrial activity, avoiding high-power ones. The coefficients used to modulate the template are estimated by maximizing, via Multi-swarm Particle Swarm Optimization, a fitness function. The modulated TMS method (mTMS) was tested on synthetic and real AEGs. Cancellation performances were assessed using: normalized mean squared error (NMSE, computed on simulated data only), reduction of ventricular activity (VDR), and percentage of segments (PP) whose power was outside the standard range of the atrial power. All testings suggested that mTMS is an improvement over TMS alone, being, on simulated data, NMSE and PP significantly decreased while VDR significantly increased. Similar results were obtained on real electrograms (median values of CS1 recordings PP: 2.44 vs. 0.38 p < 0.001; VDR: 6.71 vs. 8.15 p < 0.001).

  8. The effects of powered ankle-foot orthoses on joint kinematics and muscle activation during walking in individuals with incomplete spinal cord injury

    Directory of Open Access Journals (Sweden)

    Domingo Antoinette

    2006-02-01

    Full Text Available Abstract Background Powered lower limb orthoses could reduce therapist labor during gait rehabilitation after neurological injury. However, it is not clear how patients respond to powered assistance during stepping. Patients might allow the orthoses to drive the movement pattern and reduce their muscle activation. The goal of this study was to test the effects of robotic assistance in subjects with incomplete spinal cord injury using pneumatically powered ankle-foot orthoses. Methods Five individuals with chronic incomplete spinal cord injury (ASIA C-D participated in the study. Each subject was fitted with bilateral ankle-foot orthoses equipped with artificial pneumatic muscles to power ankle plantar flexion. Subjects walked on a treadmill with partial bodyweight support at four speeds (0.36, 0.54, 0.72 and 0.89 m/s under three conditions: without wearing orthoses, wearing orthoses unpowered (passively, and wearing orthoses activated under pushbutton control by a physical therapist. Subjects also attempted a fourth condition wearing orthoses activated under pushbutton control by them. We measured joint angles, electromyography, and orthoses torque assistance. Results A therapist quickly learned to activate the artificial pneumatic muscles using the pushbuttons with the appropriate amplitude and timing. The powered orthoses provided ~50% of peak ankle torque. Ankle angle at stance push-off increased when subjects walked with powered orthoses versus when they walked with passive-orthoses (ANOVA, p Two of the five subjects were able to control the orthoses themselves using the pushbuttons. The other three subjects found it too difficult to coordinate pushbutton timing. Orthoses assistance and maximum ankle angle at push-off were smaller when the subject controlled the orthoses compared to when the therapist-controlled the orthoses (p Conclusion Mechanical assistance from powered ankle-foot orthoses improved ankle push-off kinematics without

  9. Organic matter mineralization in frozen boreal soils-environmental constraints on catabolic and anabolic microbial activity

    Science.gov (United States)

    Oquist, Mats G.; Sparrman, Tobias; Schleucher, Jürgen; Nilsson, Mats B.

    2014-05-01

    Heterotrophic microbial mineralization of soil organic matter (SOM) and associated production and emission of atmospheric trace gases proceed during the winter months in the frozen soils of high latitude ecosystems. However, in what ways this microbial activity is constrained by the environmental conditions prevailing in a frozen soil matrix is uncertain. This presentation will address how temperature, water availability and substrate availability combine to regulate rates of microbial activity at below freezing temperatures and the implications of this activity for SOM mineralization in the surface layers of boreal forest soils experiencing seasonal freezing. We show that the amount and availability of liquid water is an integral factor regulating rates of microbial activity in the frozen soil matrix and can also explain frequently observed deviations in the temperature responses of biogenic CO2 production in frozen soils, as compared to unfrozen soils. Using stable isotope labeling (13C) we also show that the partitioning of substrate carbon, in the form of monomeric sugar (glucose), for catabolic and anabolic metabolism remain constant in the temperature range of -4C to 9C. This confirms that microbial growth may proceed even when soils are frozen. In addition we present corresponding data for organisms metabolizing polymeric substrates (cellulose) requiring exoenzymatic activity prior to substrate uptake. We conclude that the metabolic response of soil microorganism to controlling factors may change substantially across the freezing point of soil water, and also the patterns of interaction among controlling factors are affected. Thus, it is evident that metabolic response functions derived from investigations of unfrozen soils cannot be superimposed on frozen soils. Nonetheless, the soil microbial population appear very adapted to seasonal freezing with respect to their metabolic performance.

  10. Microbial life in frozen boreal soils-environmental constraints on catabolic and anabolic activity

    Science.gov (United States)

    Oquist, M. G.; Sparrman, T.; Haei, M.; Segura, J.; Schleucher, J.; Nilsson, M. B.

    2013-12-01

    Microbial activity in frozen soils has recently gained increasing attention and the fact that soil microorganisms can perform significant metabolic activity at temperatures below freezing is apparent. However, to what extent microbial activity is constrained by the environmental conditions prevailing in a frozen soil matrix is still very uncertain. This presentation will address how the fundamental environmental factors of temperature, liquid water availability and substrate availability combine to regulate rates of catabolic and anabolic microbial processes in frozen soils. The presented results are gained from investigations of the surface layers of boreal forest soils with seasonal freezing. We show that the amount and availability of liquid water is an integral factor regulating rates of microbial activity in the frozen soil matrix and can also explain frequently observed deviations in the temperature responses of biogenic CO2 production in frozen soils, as compared to unfrozen soils. In turn, the capacity for a specific soil to retain liquid water at sub-zero temperatures is controlled by the structural composition of the soil, and especially the soil organic matter is of integral importance. We also show that the partitioning of substrate carbon, in the form of monomeric sugar (glucose), for catabolic and anabolic metabolism remain constant in the temperature range of -4C to 9C. This confirms that microbial growth may proceed even when soils are frozen. In addition we present corresponding data for organisms metabolizing polymeric substrates (cellulose) requiring exoenzymatic activity. We conclude that the metabolic response of soil microorganism to controlling factors may change substantially across the freezing point of soil water, and also the patterns of interaction among controlling factors are affected. Thus, it is evident that metabolic response functions derived from investigations of unfrozen soils cannot be superimposed on frozen soils. Nonetheless

  11. Kinematic Optimization in Birds, Bats and Ornithopters

    Science.gov (United States)

    Reichert, Todd

    Birds and bats employ a variety of advanced wing motions in the efficient production of thrust. The purpose of this thesis is to quantify the benefit of these advanced wing motions, determine the optimal theoretical wing kinematics for a given flight condition, and to develop a methodology for applying the results in the optimal design of flapping-wing aircraft (ornithopters). To this end, a medium-fidelity, combined aero-structural model has been developed that is capable of simulating the advanced kinematics seen in bird flight, as well as the highly non-linear structural deformations typical of high-aspect ratio wings. Five unique methods of thrust production observed in natural species have been isolated, quantified and thoroughly investigated for their dependence on Reynolds number, airfoil selection, frequency, amplitude and relative phasing. A gradient-based optimization algorithm has been employed to determined the wing kinematics that result in the minimum required power for a generalized aircraft or species in any given flight condition. In addition to the theoretical work, with the help of an extended team, the methodology was applied to the design and construction of the world's first successful human-powered ornithopter. The Snowbird Human-Powered Ornithopter, is used as an example aircraft to show how additional design constraints can pose limits on the optimal kinematics. The results show significant trends that give insight into the kinematic operation of natural species. The general result is that additional complexity, whether it be larger twisting deformations or advanced wing-folding mechanisms, allows for the possibility of more efficient flight. At its theoretical optimum, the efficiency of flapping-wings exceeds that of current rotors and propellers, although these efficiencies are quite difficult to achieve in practice.

  12. Active fault tolerant control of piecewise affine systems with reference tracking and input constraints

    DEFF Research Database (Denmark)

    Gholami, M.; Cocquempot, V.; Schiøler, H.;

    2014-01-01

    performance of the faulty system are held. The design of the supervisory scheme is not considered here. The set of controllers is composed of a normal controller for the fault-free case, an active fault detection and isolation controller for isolation and identification of the faults, and a set of passive...... the reference signal while the control inputs are bounded. The PFTC problem is transformed into a feasibility problem of a set of LMIs. The method is applied on a large-scale live-stock ventilation model....

  13. Calcite precipitation on glass substrates and active stalagmites in Katerloch Cave (Austria): Constraints from environmental monitoring

    Science.gov (United States)

    Sakoparnig, Marlene; Boch, Ronny; Wang, Xianfeng; Lin, Ke; Spötl, Christoph; Leis, Albrecht; Gollowitsch, Anna; Dietzel, Martin

    2016-04-01

    Located near Graz at the SE-rim of the Alps Katerloch is well-known for its impressive dripstone decoration, e.g. several metres tall and relatively fast growing (0.2-0.7 mm/yr on average) candle-stick-type stalagmites. In the course of an ongoing multi-annual and partially high-resolution cave monitoring program we study modern (active) sites of carbonate deposition focusing on the site-specific growth dynamics and connection of modern regional and cave environmental conditions with petrographic, chemical and stable isotopic information captured in the speleothems. Fresh calcite precipitates on artificial (glass) substrates underneath active drip sites were collected continuously from 2006 to 2014 (eight years!). The samples (up to 7 mm thick) represent cave sections of different temperature and drip sites of partially different characteristics (e.g. drip rate). We also recovered short drill cores (up to 3 cm length, 1 cm diameter) from the top of active stalagmites probably representing the last decades to centuries of calcite crystallization. Moreover, an actively growing stalagmite (K10) comprising both modern and past calcite deposition was collected. 238U-234U-230Th dating using MC-ICP-MS of K10 (71 cm long) revealed several distinct growth intervals (separated by growth interruptions) starting at 129.1 ±1.2 kyr BP (Last Interglacial) up to now, mostly reflecting warm and humid climate intervals. High-resolution (100 μm) isotope profiles micromilled from the multi-annual modern calcite precipitates on artificial substrates revealed low δ13C values of -12.8 to -8.3 ‰ (VPDB) and relatively high δ18O of -6.9 to -4.9 ‰Ṫhe δ18O curves from all collection sites (different growth rate) record a pronounced decrease during their most recent growth period most likely corresponding to a significant decrease towards lower oxygen isotope values observed in drip waters collected in the year 2014 compared with samples from 2005 to 2007. Drip water δ2H /δ18O

  14. Teaching about Kinematics

    Science.gov (United States)

    Nelson, Jane Bray; Nelson, Jim

    2009-01-01

    Written by Jim and Jane Nelson, Teaching About Kinematics is the latest AAPT/PTRA resource book. Based on physics education research, the book provides teachers with the resources needed to introduce students to some of the fundamental building blocks of physics. It is a carefully thought-out, step-by-step laboratory-based introduction to the…

  15. Petroleum activity in the Russian Barents Sea: constraints and options for Norwegian offshore and shipping companies

    Energy Technology Data Exchange (ETDEWEB)

    Moe, Arild; Rowe, Lars

    2008-09-15

    Presently most attention in the Barents Sea is given to the Shtokman project. Experience from development of this field, where there are still many uncertainties, will have large consequences for the further development program and relations with foreign companies. The exploration activity going on is fairly limited, but over the last few years there has been a struggle over licenses and control over exploration capacity. In the medium term the goal of rapid development of the Arctic continental shelf has become intertwined with a comprehensive government effort to modernise the domestic shipbuilding industry to make it able to cover most of the needs offshore. With the shipbuilding industry in a deep crisis these goals are not fully reconcilable. Russia will either have to accept more foreign involvement, or scale down its offshore ambitions. We believe a combination of the two alternatives is likely. This means that there will still be room for foreign offshore and shipping companies, but that the total amount of activity on the continental shelf will not be as great as stated in official plans. (author). 100 refs., map

  16. Temporal and geochemical constraints on active volcanism in southeastern Papua New Guinea

    Science.gov (United States)

    Catalano, J. P.; Baldwin, S.; Fitzgerald, P. G.; Webb, L. E.; Hollocher, K.

    2010-12-01

    Active volcanism in southeastern Papua New Guinea occurs on the Papuan Peninsula (Mt. Lamington and Mt. Victory), in the Woodlark Rift (Dobu Island, SE Goodenough Island, and Western Fergusson Island), and in the Woodlark Basin. In the Woodlark Basin seafloor spreading is active and decompression melting of the mantle produces basalts. However, the cause of volcanism on the Papuan Peninsula and immediately west of active seafloor spreading rift tip in the Woodlark Basin is controversial. Previous studies have suggested active volcanism there results from 1) southward subduction of Solomon Sea lithosphere at the Trobriand Trough or 2) decompression melting as the lithosphere is extended and eventually ruptures. To evaluate these possibilities 20 samples were collected from a bimodal basalt-rhyolite suite in the D’Entrecasteaux Islands approximately 80 km west of the sea floor spreading rift tip. Siliceous ash flow tuffs on Dobu Island, Sanaroa Island, and Eastern Fergusson Island consist of sanidine/anorthoclase + Fe/Ti oxides (illmenite/ magnetite) ± quartz ± nepheline ± clinopyroxene ± xenocrystic olivine. Sanidine and K-feldspar from these ash flow tuffs yielded flat age spectra with 40Ar/39Ar isochron ages of 0.008 ± 0.002 Ma and 0.553 ± 0.001 Ma. ICP-MS trace and REE geochemistry on felsic rocks from Dobu Island and Eastern Fergusson Island yielded multi-element diagrams with enriched incompatible elements, and corresponding negative Nb, Sr, Eu, and Ti anomalies. In contrast, mafic volcanics from SE Goodenough Island are comprised of plagioclase + olivine + Fe/Ti oxides ± orthopyroxene ± clinopyroxene ± hornblende ± biotite. Biotite yielded a 40Ar/39Ar isochron age of 0.376 ± 0.05 Ma. MORB-normalized multi-element diagrams of mafic rocks from SE Goodenough Island are LREE-enriched patterns with negative Nb and positive Sr anomalies. In comparison, multi-element diagrams from previous work on mafic rocks from the New Britain arc to the north also

  17. Determining the Errors in Output Kinematic Parameters of Planar Mechanisms with a Complex Structure

    Directory of Open Access Journals (Sweden)

    Trzaska W.

    2014-11-01

    Full Text Available The study is focused on determining the errors in output kinematic parameters (position, velocity, acceleration, jerk of entire links or their selected points in complex planar mechanisms. The number of DOFs of the kinematic system is assumed to be equal to the number of drives and the rigid links are assumed to be connected by ideal, clearance-free geometric constraints. Input data include basic parameters of the mechanism with the involved errors as well as kinematic parameters of driving links and the involved errors. Output errors in kinematic parameters are determined basing on the linear theory of errors.

  18. Real-time Design Constraints in Implementing Active Vibration Control Algorithms

    Institute of Scientific and Technical Information of China (English)

    Mohammed Alamgir Hossain; Mohammad Osman Tokhi

    2006-01-01

    Although computer architectures incorporate fast processing hardware resources, high performance real-time implementation of a complex control algorithm requires an efficient design and software coding of the algorithm so as to exploit special features of the hardware and avoid associated architecture shortcomings. This paper presents an investigation into the analysis and design mechanisms that will lead to reduction in the execution time in implementing real-time control algorithms. The proposed mechanisms are exemplified by means of one algorithm, which demonstrates their applicability to real-time applications. An active vibration control (AVC) algorithm for a flexible beam system simulated using the finite difference (FD) method is considered to demonstrate the effectiveness of the proposed methods. A comparative performance evaluation of the proposed design mechanisms is presented and discussed through a set of experiments.

  19. Atomic ionization by sterile-to-active neutrino conversion and constraints on dark matter sterile neutrinos with germanium detectors

    CERN Document Server

    Chen, Jiunn-Wei; Lin, Shin-Ted; Liu, C -P; Singh, Lakhwinder; Wong, Henry T; Wu, Chih-Liang; Wu, Chih-Pan

    2016-01-01

    The transition magnetic moment of a sterile-to-active neutrino conversion gives rise to not only radiative decay of a sterile neutrino, but also its non-standard interaction (NSI) with matter. For sterile neutrinos of keV-mass as dark matter candidates, their decay signals are actively searched for in cosmic X-ray spectra. In this work, we consider the NSI that leads to atomic ionization, which can be detected by direct dark matter experiments. It is found that this inelastic scattering process for a nonrelativistic sterile neutrino has a pronounced enhancement in the differential cross section at energy transfer about half of its mass, manifesting experimentally as peaks in the measurable energy spectra. The enhancement effects gradually smear out as the sterile neutrino becomes relativistic. Using data taken with germanium detectors that have fine energy resolution in keV and sub-keV regimes, constraints on sterile neutrino mass and its transition magnetic moment are derived and compared with those from ast...

  20. Dynamic and kinematic viscosities, excess volumes and excess Gibbs energies of activation for viscous flow in the ternary mixture {1- propanol+ N,N-dimethylformamide + chloroform} at temperatures between 293.15 K and 323.15 K

    Energy Technology Data Exchange (ETDEWEB)

    Hassein-bey-Larouci, A., E-mail: hasseinbey@yahoo.fr [Laboratoire Thermodynamique et Modélisation Moléculaire, Faculté de Chimie, Université des Sciences et de la Technologie Houari Boumediene, B.P. 32, El-Alia, 16111 Bab-Ezzouar, Alger (Algeria); Igoujilen, O.; Aitkaci, A. [Laboratoire Thermodynamique et Modélisation Moléculaire, Faculté de Chimie, Université des Sciences et de la Technologie Houari Boumediene, B.P. 32, El-Alia, 16111 Bab-Ezzouar, Alger (Algeria); Segovia, J.J.; Villamañán, M.A. [TERMOCAL Research Group, Escuela de Ingenierías Industriales, Universidad de Valladolid, Paseo del Cauce, 59, 47011 Valladolid (Spain)

    2014-08-10

    Highlights: • Many engineering applications require quantitative thermodynamic data of the fluids. • Excess properties of mixtures are important in the understanding of mixing process. • The results are used to explain the molecular interaction in the mixtures. - Abstract: Dynamic and kinematic viscosities, and densities of the ternary mixture {x_1 propanol + x_2 DMF + x_3 chloroform} and of the three corresponding binary systems have been measured at 293.15, 303.15, 313.15 and 323.15 K and atmospheric pressure. The thermophysical properties, viscosity deviations (Δη), kinematic viscosity (γ), excess Gibbs energies of activation of viscous flow (G*{sup E}) and excess molar volumes (V{sup E}) have been calculated from experimental values of dynamic viscosity, η, and density, ρ. The different results have been correlated by the Redlich–Kister equation for the binary mixtures and the Cibulka equation for equation for the ternary ones.

  1. Active faulting in the Inner California Borderlands: new constraints from high-resolution multichannel seismic and multibeam bathymetric data.

    Science.gov (United States)

    Bormann, J. M.; Holmes, J. J.; Sahakian, V. J.; Klotsko, S.; Kent, G.; Driscoll, N. W.; Harding, A. J.; Wesnousky, S. G.

    2014-12-01

    Geodetic data indicate that faults offshore of Southern California accommodate 6-8 mm/yr of dextral Pacific-North American relative plate motion. In the Inner California Borderlands (ICB), modern strike-slip deformation is overprinted on topography formed during plate boundary reorganization 30-15 Ma. Despite its proximity to urban Southern California, the hazard posed by active faults in the ICB remains poorly understood. We acquired a 4000-line-km regional grid of high-resolution, 2D multichannel seismic (MCS) reflection data and multibeam bathymetry to examine the fault architecture and tectonic evolution of the ICB. We interpret the MCS data using a sequence stratigraphic approach to establish a chronostratigraphy and identify discrete episodes of deformation. We present our results in a regional fault model that distinguishes active deformation from older structures. Significant differences exist between our model of ICB deformation and existing models. Mounting evidence suggests a westward temporal migration of slip between faults in the ICB. In the eastern ICB, slip on the Newport-Inglewood/Rose Canyon fault and the neighboring Coronado Bank fault (CBF) diminishes to the north and appears to decrease over time. Undeformed Late Pliocene sediments overlie the northern extent of the CBF and the breakaway zone of the purported Oceanside Blind Thrust. Therefore, CBF slip rate estimates based on linkage with the Palos Verdes fault to the north are unwarranted. Deformation along the San Mateo, San Onofre, and Carlsbad trends is best explained as localized deformation resulting from geometrical complexities in a dextral strike-slip fault system. In the western ICB, the San Diego Trough fault (SDTF) offsets young sediments between the US/Mexico border and the eastern margin of Avalon Knoll, where the fault is spatially coincident with the San Pedro Basin fault (SPBF). Farther west, the San Clemente fault (SCF) has a strong linear bathymetric expression. The length

  2. Constraint-induced movement therapy after stroke.

    Science.gov (United States)

    Kwakkel, Gert; Veerbeek, Janne M; van Wegen, Erwin E H; Wolf, Steven L

    2015-02-01

    Constraint-induced movement therapy (CIMT) was developed to overcome upper limb impairments after stroke and is the most investigated intervention for the rehabilitation of patients. Original CIMT includes constraining of the non-paretic arm and task-oriented training. Modified versions also apply constraining of the non-paretic arm, but not as intensive as original CIMT. Behavioural strategies are mostly absent for both modified and original CIMT. With forced use therapy, only constraining of the non-paretic arm is applied. The original and modified types of CIMT have beneficial effects on motor function, arm-hand activities, and self-reported arm-hand functioning in daily life, immediately after treatment and at long-term follow-up, whereas there is no evidence for the efficacy of constraint alone (as used in forced use therapy). The type of CIMT, timing, or intensity of practice do not seem to affect patient outcomes. Although the underlying mechanisms that drive modified and original CIMT are still poorly understood, findings from kinematic studies suggest that improvements are mainly based on adaptations through learning to optimise the use of intact end-effectors in patients with some voluntary motor control of wrist and finger extensors after stroke.

  3. Global Constraints on a Heavy Neutrino

    CERN Document Server

    de Gouvêa, André

    2015-01-01

    We estimate constraints on the existence of a heavy, mostly sterile neutrino with mass between 10 eV and 1 TeV. We improve upon previous analyses by performing a global combination and expanding the experimental inputs to simultaneously include tests for lepton universality, lepton flavor violating processes, electroweak precision data, dipole moments, and neutrinoless double beta decay. Assuming the heavy neutrino and its decay products are invisible to detection, we further include, in a self-consistent manner, constraints from direct kinematic searches, the kinematics of muon decay, cosmology, and neutrino oscillations, in order to estimate constraints on the values of $|U_{e4}|^2$, $|U_{\\mu4}|^2$, and $|U_{\\tau4}|^2$.

  4. Kinematics of Einstein-Cartan universes

    CERN Document Server

    Pasmatsiou, Klaountia; Barrow, John D

    2016-01-01

    We analyse the kinematics of cosmological spacetimes with nonzero torsion, in the framework of the classical Einstein-Cartan gravity. After a brief introduction to the basic features of spaces with non-vanishing torsion, we consider a family of observers moving along timelike worldlines and focus on their kinematic behaviour. In so doing, we isolate the irreducible variables monitoring the observers' motion and derive their evolution formulae and associated constraint equations. Our aim is to identify the effects of spacetime torsion, and the changes they introduce into the kinematics of the standard, torsion-free, cosmological models. We employ a fully geometrical approach, imposing no restrictions on the material content, or any a priori couplings between torsion and spin. Also, we do not apply the familiar splitting of the equations, into a purely Riemannian component plus a torsion/spin part, at the start of our study, but only introduce it at the very end. With the general formulae at hand, we use the Ei...

  5. A KINEMATIC STUDY OF FINSWIMMING AT SURFACE

    Directory of Open Access Journals (Sweden)

    Pier-Giorgio Zanone

    2004-06-01

    Full Text Available Finswimming is a sport of speed practiced on the surface or underwater, in which performance is based on whole-body oscillations. The present study investigated the undulatory motion performed by finswimmers at the surface. This study aiming to analyze the influence of the interaction of gender, practice level, and race distance on selected kinematic parameters. Six elite and six novices finswimmers equipped with joints markers (wrist, elbow, shoulder, hip, knee, and ankle were recorded in the sagittal plane. The position of these anatomical marks was digitized at 50 Hz. An automated motion analysis software yielded velocity, vertical amplitude, frequency, and angular position. Results showed that stroke frequency decreased whereas the mean amplitude of all joints increased with increasing race distance (p < 0.01. Mean joint amplitude for the upper limbs (wrist, elbow and shoulder was smaller for experts than for novices. Whereas that of the ankle was larger, so that the oscillation amplitude increased from shoulder to ankle. Elite male finswimmers were pitching more acutely than female. Moreover, elite male finswimmers showed a smaller knee bending than novices and than elite females (p < 0.01. This indicated that elite male finswimmers attempt to reduce drag forces thanks to a weak knee bending and a low upper limbs pitch. To sum up, gender, expertise, and race distance affect the performance and its kinematics in terms frontal drag. Expertise in finswimming requires taking advantage of the mechanical constraints pertaining to hydrodynamic constraints in order to optimize performance

  6. Phreatic activity in the Valley of Desolation, Dominica (Lesser Antilles) - constraints from field investigations and experimental volcanology

    Science.gov (United States)

    Mayer, Klaus; Scheu, Bettina; Montanaro, Cristian; Yilmaz, Tim; Aßbichler, Donja; Gilg, H. Albert; Dingwell, Donald B.

    2016-04-01

    Dominica has one of the highest concentrations of potentially active volcanoes worldwide, flanked by abundant surficial geothermal manifestations: The Boiling Lake - Valley of Desolation area represents one of the most vigorous ones, hosting hot springs, mud pools, fumaroles, and steam vents. Intense alteration, together with predominantly phreatic explosive features of varying scales, characterize the whole area. The last historic eruptions in Dominica occurred at the Valley of Desolation. Phreatic eruptions are also the most likely type of volcanic activity to occur in the near future at Dominica in general and the Valley of Desolation in particular. Phreatic eruptions are up to date largely unpredictable in time and magnitude, strongly asking for constraints of eruptive conditions as well as trigger mechanisms. We conducted sampling and field mapping, together with the determination of in situ physical (density, humidity, permeability) and mechanical (strength, stiffness) properties to characterize the main active surficial area which possesses a high probability for a phreatic event. Rapid decompression experiments performed on selected samples from this area give insight into the fragmentation and ejection behavior of steam driven eruptions. These experiments were flanked by chemical analyses and laboratory measurements as porosity and granulometry. The results indicate that advanced argillic alteration in the proximity of degassing vents significantly changes the rock properties, which in turn play a crucial role for the degassing of hydrothermal systems. High-temperature acidic fluids lead to an intense alteration of the host rocks, and thereby cause the formation of a kaolinite-rich, low permeable layer above the vent. In addition, alteration enhances slope instabilities causing landslides which may cover and clog the outgassing vents. Such processes increase the likelihood of the site experiencing a pressurization, which may result in a steam

  7. Canonical quantum gravity in the Vassiliev invariants arena; 2, Constraints, habitats and consistency of the constraint algebra

    CERN Document Server

    Di Bartolo, C; Griego, J R; Pullin, J; Bartolo, Cayetano Di; Gambini, Rodolfo; Griego, Jorge; Pullin, Jorge

    2000-01-01

    In a companion paper we introduced a kinematical arena for the discussion of the constraints of canonical quantum gravity in the spin network representation based on Vassiliev invariants. In this paper we introduce the Hamiltonian constraint, extend the space of states to non-diffeomorphism invariant ``habitats'' and check that the off-shell quantum constraint commutator algebra reproduces the classical Poisson algebra of constraints of general relativity without anomalies. One can therefore consider the resulting set of constraints and space of states as a consistent theory of canonical quantum gravity.

  8. Development of a Kinematic 3D Carpal Model to Analyze In Vivo Soft-Tissue Interaction Across Multiple Static Postures

    OpenAIRE

    Marai, G. Elisabeta; Crisco, Joseph J; Laidlaw, David H.

    2009-01-01

    We developed a subject-specific kinematic model to analyze in vivo soft-tissue interaction in the carpus in static, unloaded postures. The bone geometry was extracted from a reference computed tomography volume image. The soft-tissue geometry, including cartilage and ligament tissues, was computationally modeled based on kinematic constraints; the constraints were extracted from multiple computed tomography scans corresponding to different carpal postures. The data collected in vivo was next ...

  9. Kinematics grounded on light

    CERN Document Server

    Neda, Zoltan

    2015-01-01

    The space-time of modern physics is tailored on light. We rigorously construct the basic entities needed by kinematics: geometry of the physical space and time, using as tool electromagnetic waves, and particularly light-rays. After such a mathematically orthodox construction, the special theory of relativity will result naturally. One will clearly understand and easily accept all those puzzling consequences that makes presently the special theory of relativity hard to digest. Such an approach is extremely rewarding in teaching the main ideas of Einstein's relativity theory for high-school and/or university students. Interesting speculations regarding the fundaments and future of physics are made.

  10. Kinematic geometry of gearing

    CERN Document Server

    Dooner, David B

    2012-01-01

    Building on the first edition published in 1995 this new edition of Kinematic Geometry of Gearing has been extensively revised and updated with new and original material. This includes the methodology for general tooth forms, radius of torsure', cylinder of osculation, and cylindroid of torsure; the author has also completely reworked the '3 laws of gearing', the first law re-written to better parallel the existing 'Law of Gearing" as pioneered by Leonard Euler, expanded from Euler's original law to encompass non-circular gears and hypoid gears, the 2nd law of gearing describing a unique relat

  11. A KBE tool for solving the mechanisms kinematics

    Science.gov (United States)

    Rusu, C.; Tiuca, T. L.; Noveanu, S.; Mândru, D.

    2016-08-01

    Knowledge-Based-Engineering (KBE) is a research field in which the methodologies and technologies for capturing and re-using the engineering knowledge are studied. Nowadays, the mechanisms design is accomplished by using various CAD software. Since, every CAD system includes KBE tools, those can be used to reduce time and simplify the mechanism's design process.One step in the design of the mechanisms with more than one degree of freedom is the direct and inverse kinematic analysis. This step can be difficult, because many calculations are involved and usually more than one solution exists. The geometrical constraints defined in the CAD system for the mechanism linkage's assembling, offer a simple solution for the kinematics analysis.This paper presents a KBE tool useful for kinematics analysis.The automation of repetitive tasks is implemented in an external application written in C# that it is also presented.

  12. Kinematic Control of Wheeled Snake-Like Mobile Robot

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    From a bionics viewpoint , this paper proposes a mechanical model of a wheeled snake-like mobile mechanism. On the hypothesis of the existing non-holonomic constraints on the robot kinematics, we set up the relationship among the kinetic control parameters in the snake-like movement using Lie group and Lie algebra of the principle fiber bundle and provide some theoretical control methods to realize the snake-like locomotion.

  13. Kinematics of the crustal velocity field in the western US

    Science.gov (United States)

    Pollitz, F. F.

    2008-12-01

    GPS measurements embodied in PBO and PBO Nucleus allow the crustal velocity field of the western US to be constructed in unprecedented detail. Velocity and strain fields span the entire San Andreas fault system and Cascadia subduction zone from Baja California to northern Washington as well as the continental interior including the Great Basin and Wasatch Front. Rationalizing the GPS velocity field over the several tectonic regimes provides key tests of prevailing notions of interseismic crustal deformation. In our interpretation, we begin with the premise that the load-carrying portion of the lithosphere coincides with the (seismogenic) upper crust with an effective elastic thickness of ~20 km at the time scales of interseimic motions (Thatcher and Pollitz, 2008). End member kinematic models include (1) viscoelastic relaxation of the ductile lower crust and upper mantle following large earthquakes, and (2) slip in the lower elastic lithosphere, each of which serves to localize strain around major faults during interseismic periods. More detailed kinematic models emphasize the roles of lateral variations in rigidity and/or effective elastic plate thickness as well as distributed deformation. Our modeling of western US kinematics shows that the GPS velocity field is well explained with a range of models involving a combination of all of the above components; no single endmember suffices. Zones of inferred distributed deformation in the continental interior coincide with well-known seismic belts (Eastern California Shear Zone; Walker Lane; Interseismic Mountain Belt). Continued acquisition of vector constraints on crustal motions and study of available geodetic data are needed to clarify active deformation patterns in several areas. Some outstanding issues are: The nature of distributed faulting at the margins of the Great Basin (southern Nevada Transverse Zone, northern Walker Lane); understanding how dextral shear from the eastern boundary of the Sierra Nevada

  14. Effect of modified constraint-induced movement therapy on the activities of daily living of patients with acute stroke

    Directory of Open Access Journals (Sweden)

    Wei-ming ZHANG

    2015-04-01

    Full Text Available Objective To observe the rehabilitation effect of modified constraint-induced movement therapy (mCIMT on activities of daily living (ADL in patients with acute ischemic stroke.  Methods A total of 60 patients in acute stage of cerebral stroke with limb dysfunction admitted in Ruijin Hospital from December 2012 to May 2013, were randomly divided into routine rehabilitation treatment group (control group, N = 30 and mCIMT group (N = 30. Control group was given routine rehabilitation training, 60 min each time, twice per day, 5 d per week; mCIMT group received mCIMT treatment with the similar frequency. After 2-week training, all patients were transferred to rehabilitation center for 4-week continous training. The total treatment period was 6 weeks. All of those patients received assessment before treatment and 2 weeks, 6 weeks, 12 weeks after treatment on the ability of daily living and motor function, including the modified Barthel Index (mBI, Fugl-Meyer Assessment (FMA and Berg Balance Scale (BBS.  Results Patients in both groups got increased mBI (P = 0.004, 0.000, 0.000, FMA (upper limb: P = 0.000, for all and BBS scores (P = 0.005, 0.000, 0.000 2, 6, 12 weeks after treatment. FMA (lower limb score was increased 6 and 12 weeks after treatment (P = 0.000, for all. Compared to the control group, patients in mCIMT group got increased mBI (P = 0.000, for all, FMA (upper limb: P = 0.000, for all; lower limb: P = 0.000, for all and BBS scores (P = 0.000, for all 2, 6, 12 weeks after treatment.  Conclusions mCIMT has positive therapeutic effects on the motor function of limbs in hemiplegic patients with stroke in acute stage, which can improve the balance ability and the ability of daily life, so as to raise the quality of life of patients. The efficacy of mCIMT is superior to general routine rehabilitation treatment. DOI: 10.3969/j.issn.1672-6731.2015.04.006

  15. Kinematics and Workspace Analysis of a Three-Axis Parallel Manipulator: the Orthoglide

    CERN Document Server

    Pashkevich, Anatoly; Wenger, Philippe

    2006-01-01

    The paper addresses kinematic and geometrical aspects of the Orthoglide, a three-DOF parallel mechanism. This machine consists of three fixed linear joints, which are mounted orthogonally, three identical legs and a mobile platform, which moves in the Cartesian x-y-z space with fixed orientation. New solutions to solve inverse/direct kinematics are proposed and we perform a detailed workspace and singularity analysis, taking into account specific joint limit constraints.

  16. Simulating avian wingbeat kinematics.

    Science.gov (United States)

    Parslew, Ben; Crowther, William J

    2010-12-01

    Inverse dynamics methods are used to simulate avian wingbeats in varying flight conditions. A geometrically scalable multi-segment bird model is constructed, and optimisation techniques are employed to determine segment motions that generate desired aerodynamic force coefficients with minimal mechanical power output. The results show that wingbeat kinematics vary gradually with changes in cruise speed, which is consistent with experimental data. Optimised solutions for cruising flight of the pigeon suggest that upstroke wing retraction is used as a method of saving energy. Analysis of the aerodynamic force coefficient variation in high and low speed cruise leads to the proposal that a suitable gait metric should include both thrust and lift generation during each half-stroke.

  17. Rattlesnake strike behavior: kinematics

    Science.gov (United States)

    Kardong; v

    1998-03-01

    The predatory behavior of rattlesnakes includes many distinctive preparatory phases leading to an extremely rapid strike, during which venom is injected. The rodent prey is then rapidly released, removing the snake's head from retaliation by the prey. The quick action of the venom makes possible the recovery of the dispatched prey during the ensuing poststrike period. The strike is usually completed in less than 0.5 s, placing a premium on an accurate strike that produces no significant errors in fang placement that could result in poor envenomation and subsequent loss of the prey. To clarify the basis for effective strike performance, we examined the basic kinematics of the rapid strike using high-speed film analysis. We scored numerous strike variables. Four major results were obtained. (1) Neurosensory control of the strike is based primarily upon sensory inputs via the eyes and facial pits to launch the strike, and upon tactile stimuli after contact. Correction for errors in targeting occurs not by a change in strike trajectory, but by fang repositioning after the jaws have made contact with the prey. (2) The rattlesnake strike is based upon great versatility and variation in recruitment of body segments and body postures. (3) Forces generated during acceleration of the head are transferred to posterior body sections to decelerate the head before contact with the prey, thereby reducing impact forces upon the snake's jaws. (4) Body acceleration is based on two patterns of body displacement, one in which acute sections of the body open like a gate, the other in which body segments flow around postural curves similar to movements seen during locomotion. There is one major implication of these results: recruitment of body segments, launch postures and kinematic features of the strike may be quite varied from strike to strike, but the overall predatory success of each strike by a rattlesnake is very consistent.

  18. Geochemical and geochronological constraints on the origin and evolution of rocks in the active Woodlark Rift of Papua New Guinea

    Science.gov (United States)

    Zirakparvar, Nasser Alexander

    Tectonically active regions provide important natural laboratories to glean information that is applicable to developing a better understanding of the geologic record. One such area of the World is Papua New Guinea, much of which is situated in an active and transient plate boundary zone. The focus of this PhD research is to develop a better understanding of rocks in the active Woodlark Rift, situated in Papua New Guinea's southernmost reaches. In this region, rifting and lithospheric rupture is occurring within a former subduction complex where there is a history of continental subduction and (U)HP metamorphism. The lithostratigraphic units exposed in the Woodlark Rift provide an opportunity to better understand the records of plate boundary processes at many scales from micron-sized domains within individual minerals to regional geological relationships. This thesis is composed of three chapters that are independent of one another but are all related to the overall goal of developing a better understanding of the record of plate boundary processes in the rocks currently exposed in the Woodlark Rift. The first chapter, published in its entirety in Earth and Planetary Science Letters (2011 v. 309, p. 56 - 66), is entitled 'Lu-Hf garnet geochronology applied to plate boundary zones: Insights from the (U)HP terrane exhumed within the Woodlark Rift'. This chapter focuses on the use of the Lu-Hf isotopic system to date garnets in the Woodlark Rift. Major findings of this study are that some of the rocks in the Woodlark Rift preserve a Lu-Hf garnet isotopic record of initial metamorphism and continental subduction occurring in the Late Mesozoic, whereas others only preserve a record of tectonic processes related to lithospheric rupture during the initiation of rifting in the Late Cenozoic. The second chapter is entitled 'Geochemical and geochronological constraints on the origin of rocks in the active Woodlark Rift of Papua New Guinea: Recognizing the dispersed

  19. Cortical fMRI activation to opponents' body kinematics in sport-related anticipation: expert-novice differences with normal and point-light video.

    Science.gov (United States)

    Wright, M J; Bishop, D T; Jackson, R C; Abernethy, B

    2011-08-18

    Badminton players of varying skill levels viewed normal and point-light video clips of opponents striking the shuttle towards the viewer; their task was to predict in which quadrant of the court the shuttle would land. In a whole-brain fMRI analysis we identified bilateral cortical networks sensitive to the anticipation task relative to control stimuli. This network is more extensive and localised than previously reported. Voxel clusters responding more strongly in experts than novices were associated with all task-sensitive areas, whereas voxels responding more strongly in novices were found outside these areas. Task-sensitive areas for normal and point-light video were very similar, whereas early visual areas responded differentially, indicating the primacy of kinematic information for sport-related anticipation.

  20. Microgravity Vibration Isolation System Based on Parallel Kinematic Communications

    Science.gov (United States)

    Russkin, Alexander; Postojuk, Nikolay

    The paper is devoted to the construction of an active vibration isolation system of experimental and technological equipment operating in microgravity conditions. Space experiments associated with obtaining ultrapure materials are required the residual level of microgravity vibration from mmug to mg at the frequency range from 0.01 Hz to 100 Hz in the experiment area. This residual level of microgravity vibration is difficult to achieve by conventional passive protection systems. To date the different types of active vibration isolation systems are constructed, such as STABLE, ARIS, MIM, g-LIMIT and MVIS, but their characteristics and geometrical parameters do not always satisfy the given technological requirements. In this paper, the mechanism with parallel kinematic constraints (MPKS) is proposed for constructing microgravity active vibration isolation system, which provides protection against vibrations in six degrees of freedom and can be scaled depending on the specific tasks. MPKS distinguishing feature is the presence of closed kinematic chain, which provide high rigidity of the structure, reduce the mass of moving parts and reduce the load on the actuator. As a result, this increases the dynamics and positioning accuracy MPKS. The proposed version of microgravity vibration isolation system consists of two main parts: the electromechanical assembly and control unit. The main specifications for the constituent parts of the system are defined. A comparative analysis of different types of actuators and sensors for electromechanical assembly is carried out. The appropriate components to provide the desired specifications are selected. There are proposed to use piezoelectric motors as actuators in electromechanical assembly. Mathematical models of MPKS with six degrees of freedom and control system are considered. The structure of the control system and controller type is selected. A mathematical model of proposed microgravity vibration isolation system is

  1. BASALT 1: Extravehicular Activity Science Operations Concepts under Communication Latency and Bandwidth Constraints at Craters of the Moon, Idaho

    Science.gov (United States)

    Chappell, Steven P.; Beaton, Kara; Miller, Matthew J.; Lim, Darlene S. S.; Abercromby, Andrew F. J.

    2017-01-01

    An over-arching goal of the multi-year Biologic Analog Science Associated with Lava Terrains (BASALT) project is to iteratively develop, implement, and evaluate concepts of operations (ConOps) and supporting capabilities intended to enable and enhance human exploration of Mars. Geological and biological scientific fieldwork is being conducted during four total deployments at two high-fidelity Mars analogs, all within simulated Mars mission conditions that are based on current architectural assumptions for Mars exploration missions. Specific capabilities being evaluated include the use of mobile science platforms, extravehicular informatics, communication and navigation packages, advanced science mission planning tools, and scientifically-relevant instrument packages to achieve the project goals. This paper describes the planning, execution, and results of the first field deployment, referred to as BASALT 1, which consisted of a series of 12 simulated extravehicular activities (EVAs) on the lava terrains of Craters of the Moon, Idaho. Scientific objectives of the EVAs related to determination of how microbial communities and habitability correlate with the physical and geochemical characteristics of chemically-altered basalt environments. The concept of operations (ConOps) and capabilities deployed and tested during BASALT 1 were based on extensive data from previous NASA trade studies and analog testing, and the primary research question was whether those ConOps and capabilities would work acceptably when performing real (non-simulated) biological and geological scientific exploration under four different communication scenarios. Specifically, communication latencies of 5 and 15 minutes one-way light time (OWLT) were tested; these delays fall within the range of 4 to 22 minute OWLT delays that would be experienced during a Mars mission. Science operations were also conducted under low bandwidth conditions (0.512 Mb/s uplink, 1.54 Mb/s downlink), representing a

  2. Fault-related fold kinematics recorded by terrestrial growth strata, Sant Llorenç de Morunys, Pyrenees Mountains, NE Spain

    Science.gov (United States)

    Carrigan, James H.; Anastasio, David J.; Kodama, Kenneth P.; Parés, Josep M.

    2016-10-01

    Foreland basin growth strata are ideal recorders of deformation rates and kinematics in tectonically active regions. This study develops a high-resolution chronostratigraphic age model to determine folding rates in the Eocene-Oligocene terrestrial growth strata of the Berga Conglomerate Group, NE Spain. The Berga Conglomerate Group was sampled for rock magnetic, magnetostratigraphic, and magnetic susceptibility (χ) cyclostratigraphy analyses. Analysis of rock magnetic measurements indicate a mixed mineral assemblage with both paramagnetic and ferromagnetic minerals. A new magnetic reversal stratigraphy constrains the time frame of folding and is in agreement with previous interpretations. Time series analysis of χ variations show statistically significant power at expected orbital frequencies and provides precession-scale (20 kyr) temporal resolution. Strain measurements including anisotropy of magnetic susceptibility (AMS) fabrics and bedding plane strain worm burrow distortion are consistent with fixed hinge, flexural folding kinematics. Fault-related folding was modeled using χ cyclostratigraphy timing and strain measurement kinematic constraints. The onset of folding was at 33.85 Ma and the end of deformation is less constrained but is younger than 31.06 Ma. Deformation and sediment accumulation rates are unsteady at 20 kyr time scales but appear artificially steady at polarity chron time scales.

  3. Changes of right-hemispheric activation after constraint-induced, intensive language action therapy in chronic aphasia: fMRI evidence from auditory semantic processing

    Directory of Open Access Journals (Sweden)

    Bettina eMohr

    2014-11-01

    Full Text Available The role of the two hemispheres in the neurorehabilitation of language is still under dispute. This study explored the changes in language-evoked brain activation over a two-week treatment interval with intensive constraint induced aphasia therapy (CIAT, which is also called intensive language action therapy (ILAT. Functional magnetic resonance imaging (fMRI was used to assess brain activation in perilesional left hemispheric and in homotopic right hemispheric areas during passive listening to high and low-ambiguity sentences and non-speech control stimuli in chronic non-fluent aphasia patients. All patients demonstrated significant clinical improvements of language functions after therapy. In an event-related fMRI experiment, a significant increase of BOLD signals was manifest in right inferior frontal and temporal areas. This activation increase was stronger for highly ambiguous sentences than for unambiguous ones. These results suggest that the known language improvements brought about by intensive constraint-induced language action therapy at least in part relies on circuits within the right-hemispheric homologues of left-perisylvian language areas, which are most strongly activated in the processing of semantically complex language.

  4. Changes of right-hemispheric activation after constraint-induced, intensive language action therapy in chronic aphasia: fMRI evidence from auditory semantic processing.

    Science.gov (United States)

    Mohr, Bettina; Difrancesco, Stephanie; Harrington, Karen; Evans, Samuel; Pulvermüller, Friedemann

    2014-01-01

    The role of the two hemispheres in the neurorehabilitation of language is still under dispute. This study explored the changes in language-evoked brain activation over a 2-week treatment interval with intensive constraint induced aphasia therapy (CIAT), which is also called intensive language action therapy (ILAT). Functional magnetic resonance imaging (fMRI) was used to assess brain activation in perilesional left hemispheric and in homotopic right hemispheric areas during passive listening to high and low-ambiguity sentences and non-speech control stimuli in chronic non-fluent aphasia patients. All patients demonstrated significant clinical improvements of language functions after therapy. In an event-related fMRI experiment, a significant increase of BOLD signal was manifest in right inferior frontal and temporal areas. This activation increase was stronger for highly ambiguous sentences than for unambiguous ones. These results suggest that the known language improvements brought about by intensive constraint-induced language action therapy at least in part relies on circuits within the right-hemispheric homologs of left-perisylvian language areas, which are most strongly activated in the processing of semantically complex language.

  5. SKIRT: Stellar Kinematics Including Radiative Transfer

    Science.gov (United States)

    Baes, Maarten; Dejonghe, Herwig; Davies, Jonathan

    2011-09-01

    SKIRT is a radiative transfer code based on the Monte Carlo technique. The name SKIRT, acronym for Stellar Kinematics Including Radiative Transfer, reflects the original motivation for its creation: it has been developed to study the effects of dust absorption and scattering on the observed kinematics of dusty galaxies. In a second stage, the SKIRT code was extended with a module to self-consistently calculate the dust emission spectrum under the assumption of local thermal equilibrium. This LTE version of SKIRT has been used to model the dust extinction and emission of various types of galaxies, as well as circumstellar discs and clumpy tori around active galactic nuclei. A new, extended version of SKIRT code can perform efficient 3D radiative transfer calculations including a self-consistent calculation of the dust temperature distribution and the associated FIR/submm emission with a full incorporation of the emission of transiently heated grains and PAH molecules.

  6. On the kinematic age of RZ Psc

    Science.gov (United States)

    Potravnov, I. S.; Grinin, V. P.

    2013-11-01

    RZ Psc belongs to the family of young UX Ori stars whose photometric activity is due to strong extinction variations in the circumstellar disks surrounding them. However, in contrast to all the remaining stars of this type, no evidence of youth has been detected for RZ Psc until recently. A rough estimate of the star's kinematic age was made for the first time in our previous paper (Grinin et al. 2010). It shows that RZ Psc is intermediate in its evolutionary status between young stars in Orion and stars with debris disks. In this paper, we provide a refined estimate of the kinematic age for the star confirming this conclusion. According to this estimate, the age of RZ Psc is approximately 25 ± 5 Myr at M * = 1 M ⊙.

  7. Kinematics of Haro11 - the miniature Antennae

    CERN Document Server

    Östlin, Göran; Cumming, Robert; Fathi, Kambiz; Bergvall, Nils; Adamo, Angela; Amram, Philippe; Hayes, Matthew

    2015-01-01

    (abridged) Luminous blue compact galaxies are among the most active galaxies in the local universe in terms of their star formation rate per unit mass. They may be seen as the local analogs of higher redshift Lyman Break Galaxies. Studies of their kinematics is key to understanding what triggers their unusually active star formation In this work we investigate the kinematics of stars and ionised gas in Haro11, one of the most luminous blue compact galaxies in the local universe. Previous works have indicated that many such galaxies may be triggered by galaxy mergers. We have employed Fabry-Perot interferometry, long-slit spectroscopy and Integral Field Unit (IFU) spectroscopy to explore the kinematics of Haro11. We target the near infrared Calcium triplet to derive the stellar velocity field and velocity dispersion. Ionised gas is analysed through emission lines from hydrogen, [OIII] , and [SIII]. When spectral resolution and signal to noise allows we investigate the the line profile in detail and identify mu...

  8. Kinematic precision of gear trains

    Science.gov (United States)

    Litvin, F. L.; Goldrich, R. N.; Coy, J. J.; Zaretsky, E. V.

    1982-01-01

    Kinematic precision is affected by errors which are the result of either intentional adjustments or accidental defects in manufacturing and assembly of gear trains. A method for the determination of kinematic precision of gear trains is described. The method is based on the exact kinematic relations for the contact point motions of the gear tooth surfaces under the influence of errors. An approximate method is also explained. Example applications of the general approximate methods are demonstrated for gear trains consisting of involute (spur and helical) gears, circular arc (Wildhaber-Novikov) gears, and spiral bevel gears. Gear noise measurements from a helicopter transmission are presented and discussed with relation to the kinematic precision theory.

  9. Kinematic precision of gear trains

    Science.gov (United States)

    Litvin, F. L.; Goldrich, R. N.; Coy, J. J.; Zaretsky, E. V.

    1983-01-01

    Kinematic precision is affected by errors which are the result of either intentional adjustments or accidental defects in manufacturing and assembly of gear trains. A method for the determination of kinematic precision of gear trains is described. The method is based on the exact kinematic relations for the contact point motions of the gear tooth surfaces under the influence of errors. An approximate method is also explained. Example applications of the general approximate methods are demonstrated for gear trains consisting of involute (spur and helical) gears, circular arc (Wildhaber-Novikov) gears, and spiral bevel gears. Gear noise measurements from a helicopter transmission are presented and discussed with relation to the kinematic precision theory. Previously announced in STAR as N82-32733

  10. Tensor Networks from Kinematic Space

    CERN Document Server

    Czech, Bartlomiej; McCandlish, Samuel; Sully, James

    2015-01-01

    We point out that the MERA network for the ground state of a 1+1-dimensional conformal field theory has the same structural features as kinematic space---the geometry of CFT intervals. In holographic theories kinematic space becomes identified with the space of bulk geodesics studied in integral geometry. We argue that in these settings MERA is best viewed as a discretization of the space of bulk geodesics rather than of the bulk geometry itself. As a test of this kinematic proposal, we compare the MERA representation of the thermofield-double state with the space of geodesics in the two-sided BTZ geometry, obtaining a detailed agreement which includes the entwinement sector. We discuss how the kinematic proposal can be extended to excited states by generalizing MERA to a broader class of compression networks.

  11. Tensor networks from kinematic space

    Science.gov (United States)

    Czech, Bartlomiej; Lamprou, Lampros; McCandlish, Samuel; Sully, James

    2016-07-01

    We point out that the MERA network for the ground state of a 1+1-dimensional conformal field theory has the same structural features as kinematic space — the geometry of CFT intervals. In holographic theories kinematic space becomes identified with the space of bulk geodesics studied in integral geometry. We argue that in these settings MERA is best viewed as a discretization of the space of bulk geodesics rather than of the bulk geometry itself. As a test of this kinematic proposal, we compare the MERA representation of the thermofield-double state with the space of geodesics in the two-sided BTZ geometry, obtaining a detailed agreement which includes the entwinement sector. We discuss how the kinematic proposal can be extended to excited states by generalizing MERA to a broader class of compression networks.

  12. The Ambiguous Role of Constraints in Creativity

    DEFF Research Database (Denmark)

    Biskjær, Michael Mose; Onarheim, Balder; Wiltschnig, Stefan

    2011-01-01

    The relationship between creativity and constraints is often described in the literature either in rather imprecise, general concepts or in relation to very specific domains. Cross-domain and cross-disciplinary takes on how the handling of constraints influences creative activities are rare. In t......-disciplinary research into the ambiguous role of constraints in creativity....

  13. Spatially Resolving the Kinematics of the <100 {\\mu}as Quasar Broad Line Region using Spectroastrometry

    CERN Document Server

    Stern, Jonathan; Pott, Jörg-Uwe

    2015-01-01

    The broad line region (BLR) of luminous active galactic nuclei (AGN) is a prominent observational signature of the accretion flow around supermassive black holes, which can be used to measure their masses (M_BH) over cosmic history. Due to the <100 {\\mu}as angular size of the BLR, current direct constraints on BLR kinematics are limited to those provided by reverberation mapping studies, which are most efficiently carried out on low-luminosity L and low-redshift z AGN. We analyze the possibility to measure the BLR size and study its kinematic structure using spectroastrometry, whereby one measures the spatial position centroid of emission line photons as a function of velocity. We calculate the expected spectroastrometric signal of a rotation-dominated BLR for various assumptions about the ratio of random to rotational motions, and the radial distribution of the BLR gas. We show that for hyper-luminous quasars at z < 2.5, the size of the low-ionization BLR can already be constrained with existing telesc...

  14. Automatic Design Theory and Realization of Kinematic Schemes for Mechanism System

    Institute of Scientific and Technical Information of China (English)

    YE Zhi-gang; ZOU Hui-jun; GUO Wei-zhong; HU Song; TIAN Yong-li; XU Yong

    2006-01-01

    Based on an analysis of mechanism combination methods of a current mechanism system kinematic scheme,inpuf/output kinematic behavior and their constraint relations were proposed to represent the kinematic behavior knowledge of a mechanism system.Furthermore,a tree stmcture of a kinematic behavior decomposition process for a mechanism system was provided.Considering multiple outputs for a mechanism system,the matching algorithm and the attributes propagation method of kinematic behavior were used to generate a mechanism combination scheme.Its intermediate design solution and the constraint relations between input and output are generated to fill the common blackboard.Moreover,using information in the blackboard as input motion.the behavior attributes of other process actions are transmitted to attribute items of the blackboard,which finally enables a computer-aided automatic design process of a mechanism system kinematic scheme.To avoid the problem of schemes combination explosion caused by unbounded depth in the search process,bounded depth-first search was used to control the number of expanded hierarchies for a design tree.Finally.an example was given to show its feasibility and solution efficiency.

  15. Mg II & C IV Kinematics vs. Stellar Kinematics in Galaxies

    CERN Document Server

    Churchill, C W; Churchill, Chris; Steidel, Chuck

    2002-01-01

    Comparisons of the kinematics of Mg II absorbing gas and the stellar rotation curves in 0.5 < z < 1.0 spiral galaxies suggests that, at least in some cases, the extended gaseous envelopes may be dynamically coupled to the stellar matter. A strong correlation exists between the overall kinematic spread of Mg II absorbing gas and C IV absorption strength, and therefore kinematics of the higher-ionization gas. Taken together, the data may suggest a "halo/disk connection" between z~1 galaxies and their extended gaseous envelopes. Though the number of galaxies in our sample are few, there are no clear examples that suggest the gas is accreting/infalling isotropically about the galaxies from the intergalactic medium.

  16. Kinematics, seismotectonics and seismic potential of the eastern sector of the European Alps from GPS and seismic deformation data

    Science.gov (United States)

    Serpelloni, E.; Vannucci, G.; Anderlini, L.; Bennett, R. A.

    2016-10-01

    We present a first synoptic view of the seismotectonics and kinematics of the eastern sector of the European Alps using geodetic and seismological data. The study area marks the boundary between the Adriatic and the Eurasian plates, through a wide zone of deformation including a variety of tectonic styles within a complex network of crustal and lithospheric faults. A new dense GPS velocity field, new focal mechanisms and seismic catalogues, with uniformly re-calibrated magnitudes (from 1005), are used to estimate geodetic and seismic deformation rates and to develop interseismic kinematic and fault locking models. Kinematic indicators from seismological and geodetic data are remarkably consistent at different spatial scales. In addition to large-scale surface motion, GPS velocities highlight more localized deformation features revealing a complex configuration of interacting tectonic blocks, for which new constraints are provided in this work accounting for elastic strain build up at faults bonding rotating blocks. The geodetic and seismological data highlight two belts of higher deformation rates running WSW-ENE along the Eastern Southern Alps (ESA) in Italy and E-W in Slovenia, where deformation is more distributed. The highest geodetic strain-rates are observed in the Montello-Cansiglio segment of the ESA thrust front, for which the higher density of the GPS network provides indications of limited interseismic locking. Most of the dextral shear between the Eastern Southern Alps and the Eastern Alps blocks is accommodated along the Fella-Sava fault rather than the Periadriatic fault. In northern Croatia and Slovenia geodetic and seismological data allow constraining the kinematics of the active structures bounding the triangular-shaped region encompassing the Sava folds, which plays a major role in accommodating the transition from Adria- to Pannonian-like motion trends. The analysis of the seismic and geodetic moment rates provides new insights into the seismic

  17. KINEMATIC DESIGN OF A RECONFIGURABLE MINIATURE PARALLEL KINEMATIC MACHINE

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The kinematic design of a reconfigurable miniature parallel kinematic machine is dealt with. It shows that the reconfigurability may be realized by packaging a tripod-based parallel mechanism with fixed length struts into a compact and rigid frame with which the different configurations can be formed. Utilizing a dual parameter model, the influences of the geometrical parameters on the dexterous performance and the workspace/machine volume ratio are investigated. A novel global performance index for the dimensional synthesis is proposed and optimized, resulting in a set of dimensionless geometrical parameters.

  18. Kinematics and computation of workspace for adaptive geometry structures

    Science.gov (United States)

    Pourki, Forouza; Sosa, Horacio

    1993-09-01

    A new feature in the design of smart structures is the capability of the structure to respond autonomously to undesirable phenomena and environment. This capability is often synonymous to the requirement that the structure should assume a set of different geometric shapes or adapt to a set of kinematic constraints to accomplish a maneuver. Systems with these characteristics have been referred to as `shape adaptive' or `variable geometry' structures. The present paper introduces a basis for the kinematics and work space studies of statically deterministic truss structures which are shape adaptive. The difference between these structures and the traditional truss structures, which are merely built to support the weight and may be modelled by finite element methods, is the fact that these variable geometry structures allow for large (and nonlinear) deformations. On the other hand, these structures unlike structures composed of well investigated `four bar mechanisms,' are statically deterministic.

  19. Radiative distortion of kinematic edges in cascade decays

    CERN Document Server

    Beneke, Martin; Mück, Alexander; Ubiali, Maria

    2016-01-01

    Kinematic edges of cascade decays of new particles produced in high-energy collisions may provide important constraints on the involved particles' masses. For the exemplary case of gluino decay $\\tilde{g}\\to q\\bar q \\tilde{\\chi}$ into a pair of quarks and a neutralino through a squark resonance, we study the hadronic invariant mass distribution in the vicinity of the kinematic edge. We perform a next-to-leading order calculation in the strong coupling $\\alpha_s$ and the ratio of squark width and squark mass $\\Gamma_\\tilde{q}/m_\\tilde{q}$, based on a systematic expansion in $\\Gamma_\\tilde{q}/m_\\tilde{q}$. The separation into hard, collinear and soft contributions elucidates the process dependent and universal features of distributions in the edge region, represented by on-shell decay matrix elements, universal jet functions and a soft function that depends on the resonance propagator and soft Wilson lines.

  20. A constrained generalised- method for coupling rigid parallel chain kinematics and elastic bodies

    Science.gov (United States)

    Gransden, Derek I.; Bornemann, P. Burkhard; Rose, Michael; Nitzsche, Fred

    2015-03-01

    A problem arises from combining flexible rotorcraft blades with stiffer mechanical links, which form a parallel kinematic chain. This paper introduces a method for solving index-3 differential algebraic equations for coupled stiff and elastic body systems with closed-loop kinematics. Rigid body dynamics and elastic body mechanics are independently described according to convenient mathematical measures. Holonomic constraint equations couple both the parallel chain kinematics and describe the coupling between the rigid and continuum bodies. Lagrange multipliers enforce the kinetic conditions for both sets of constraints. Additionally, to prevent numerical inaccuracy from inverting stiff mechanical matrices, a scaling factor normalises the dynamic tangential stiffness matrix. Finally, example tests show the verification of the algorithm with respect to existing computational tests and the accuracy of the model for cases relevant to the problem definition.

  1. Tibiofemoral conformity and kinematics of rotating-bearing knee prostheses.

    Science.gov (United States)

    D'Lima, D D; Trice, M; Urquhart, A G; Colwell, C W

    2001-05-01

    Increasing tibiofemoral articular conformity theoretically increases articular contact area and reduces contact stresses in total knee arthroplasty. Fixed-bearing knee designs possess relatively low tibiofemoral conformity, in part to allow tibiofemoral rotation without generating excessive stresses at the articulation or the implant-bone interface. This study analyzed knee kinematics of mobile-bearing designs in a closed chain dynamic knee extension model in posterior cruciate-retaining design with high- and low tibiofemoral conformity and posterior cruciate-substituting designs with and without rotational constraint. Overall, for all conditions, the mobile-bearing insert rotated with the femur in the presence of tibiofemoral axial rotation. In addition, the correlation of bearing rotation with femoral rotation was stronger for the high-conformity and rotationally-constrained designs than for the low-conformity designs and strongest for the posterior cruciate-retaining high-conformity condition. Changes in conformity or rotational constraint did not appear to affect femoral roll back, tibiofemoral axial rotation, or varus-valgus angulation. The results suggest that mobile-bearing inserts rotate with the femur and increasing conformity or rotational constraint in mobile-bearing design knee prostheses does not affect knee kinematics adversely, at least under closed chain knee extension conditions in vitro.

  2. Clifford Fibrations and Possible Kinematics

    Science.gov (United States)

    McRae, Alan S.

    2009-07-01

    Following Herranz and Santander [Herranz F.J., Santander M., Mem. Real Acad. Cienc. Exact. Fis. Natur. Madrid 32 (1998), 59-84, physics/9702030] we will construct homogeneous spaces based on possible kinematical algebras and groups [Bacry H., Levy-Leblond J.-M., J. Math. Phys. 9 (1967), 1605-1614] and their contractions for 2-dimensional spacetimes. Our construction is different in that it is based on a generalized Clifford fibration: Following Penrose [Penrose R., Alfred A. Knopf, Inc., New York, 2005] we will call our fibration a Clifford fibration and not a Hopf fibration, as our fibration is a geometrical construction. The simple algebraic properties of the fibration describe the geometrical properties of the kinematical algebras and groups as well as the spacetimes that are derived from them. We develop an algebraic framework that handles all possible kinematic algebras save one, the static algebra.

  3. Latest Advances in Robot Kinematics

    CERN Document Server

    Husty, Manfred

    2012-01-01

    This book is  of interest to researchers inquiring about modern topics and methods in the kinematics, control and design of robotic manipulators. It considers the full range of robotic systems, including serial, parallel and cable driven manipulators, both planar and spatial. The systems range from being less than fully mobile to kinematically redundant to overconstrained. In addition to recognized areas, this book also presents recent advances in emerging areas such as the design and control of humanoids and humanoid subsystems, and the analysis, modeling and simulation of human body motions, as well as the mobility analysis of protein molecules and the development of machines which incorporate man.

  4. Kinematics of the Danakil microplate

    Science.gov (United States)

    Eagles, Graeme; Gloaguen, Richard; Ebinger, Cynthia

    2002-10-01

    A refinement and extrapolation of recent motion estimates for the Danakil microplate, based on ancient kinematic indicators in the Afar region, describes the evolution of a microplate in the continental realm. The Danakil horst is an elevated part of this microplate, exposing a Precambrian basement within the Afar depression, the site of the Nubia-Somalia-Arabia triple junction. We compare evidence for strike- or oblique-slip faults in data from the Afar depression and southern Red Sea to small circles about published poles of rotation for the Danakil microplate with respect to Nubia. A reconstruction about the preferred pole reunites lengths of a Precambrian shear zone on the Nubia and Danakil sides and preserves a uniform basement fabric strike through Nubia, Danakil and Yemen. Since at least magnetic chron C5 (˜11 Ma) Danakil rotated about a different pole with respect to Nubia than either Somalia or Arabia, but between chrons C5 and C2A Nubia-Danakil motion was a close approximation to Nubia-Somalia motion. Since C2A relative motions of the Danakil microplate have been independent of movements on any of the neighbouring plate boundaries. We relate this to the onset of oceanic-type accretion within Afar. The resulting eastwards acceleration of Danakil was accommodated by westwards propagation of the Gulf of Aden rift that became the new, discrete, plate boundary between the Danakil microplate and the Somalia plate. Present-day activity suggests that the Red Sea and Aden rifts will link through Afar, thereby isolating the Danakil horst as a microcontinent on the Arabian margin.

  5. Development of a Kinematic 3D Carpal Model to Analyze In Vivo Soft-Tissue Interaction Across Multiple Static Postures

    Science.gov (United States)

    Marai, G. Elisabeta; Crisco, Joseph J.; Laidlaw, David H.

    2012-01-01

    We developed a subject-specific kinematic model to analyze in vivo soft-tissue interaction in the carpus in static, unloaded postures. The bone geometry was extracted from a reference computed tomography volume image. The soft-tissue geometry, including cartilage and ligament tissues, was computationally modeled based on kinematic constraints; the constraints were extracted from multiple computed tomography scans corresponding to different carpal postures. The data collected in vivo was next coupled with numerical simulation in order to analyze the role of soft-tissues in different postures. The resulting model extends the state of biomecanical modeling by incorporating soft-tissue constraints across the carpus range of motion, while successfully using only physiological constraints. The model results suggest that soft-tissue wrapping constraints have substantial impact on carpus stability. PMID:19965271

  6. Stochastic Constraint Programming

    OpenAIRE

    Walsh, Toby

    2009-01-01

    To model combinatorial decision problems involving uncertainty and probability, we introduce stochastic constraint programming. Stochastic constraint programs contain both decision variables (which we can set) and stochastic variables (which follow a probability distribution). They combine together the best features of traditional constraint satisfaction, stochastic integer programming, and stochastic satisfiability. We give a semantics for stochastic constraint programs, and propose a number...

  7. Ordered Kinematic Endpoints for 5-body Cascade Decays

    CERN Document Server

    Klimek, Matthew D

    2016-01-01

    We present expressions for the kinematic endpoints of 5-body cascade decay chains proceeding through all possible combinations of 2-body and 3-body decays, with one stable invisible particle in the final decay stage. When an invariant mass can be formed in multiple ways by choosing different final state particles from a common vertex, we introduce techniques for finding the sub-leading endpoints for all indistinguishable versions of the invariant mass. In contrast to short decay chains, where sub-leading endpoints are linearly related to the leading endpoints, we find that in 5-body decays, they provide additional independent constraints on the mass spectrum.

  8. Stability analysis for natural slope by kinematical approach

    Institute of Scientific and Technical Information of China (English)

    孙志彬; 覃长兵

    2014-01-01

    The stability of natural slope was analyzed on the basis of limit analysis. The sliding model of a kind of natural slope was presented. A new kinematically admissible velocity field for the new sliding model was constructed. The stability factor formulation by the upper bound theorem leads to a classical nonlinear programming problem, when the external work rate and internal energy dissipation were solved, and the constraint condition of the programming problem was given. The upper bound optimization problem can be solved efficiently by applying a nonlinear SQP algorithm, and stability factor was obtained, which agrees well with previous achievements.

  9. Examination of center of pressure displacement and muscle activity of the hip girdle muscles on lateral movement in the sitting position, focusing on kinematic features before and after the start of exercise

    Science.gov (United States)

    Ikeda, Kouji; Suehiro, Kenji; Kizu, Akito; Kunieda, Hideki; Takasaki, Hirokazu; Suzuki, Toshiaki

    2017-01-01

    [Purpose] This study aimed to evaluate the kinematic characteristics at the start of lateral movement in the sitting position, for application in physical therapy. [Subjects and Methods] Eleven healthy male subjects (mean age, 24.8 ± 3.7 years) were included in the study after they provided informed consent. The electromyographic activities of the tensor fascia lata, gluteus medius, and rectus femoris, and the center of pressure (COP) displacement during lateral reach in the sitting position were measured. The task was recorded on video for analysis. [Results] In almost all subjects, before the beginning of the task, the electromyographic activity in the opposite side of each studied muscle was recorded, and the opposite and anterior displacement of the COP was observed. The video analysis revealed that all subjects showed lateral displacement of the thoracic part of the trunk after the start of the task. However, the lumbar region and pelvis maintained their starting positions. [Conclusion] COP displacement occurred in the reverse reaction before the task, and this involved the hip girdle muscles of the opposite side. A reverse reaction displaced the pelvis to the opposite side to ensure instability of posture through side tilting of the trunk at the beginning of the task. PMID:28356627

  10. Impact responses of the cervical spine: A computational study of the effects of muscle activity, torso constraint, and pre-flexion.

    Science.gov (United States)

    Nightingale, Roger W; Sganga, Jake; Cutcliffe, Hattie; Bass, Cameron R 'Dale'

    2016-02-29

    Cervical spine injuries continue to be a costly societal problem. Future advancements in injury prevention depend on improved physical and computational models, which are predicated on a better understanding of the neck response during dynamic loading. Previous studies have shown that the tolerance of the neck is dependent on its initial position and its buckling behavior. This study uses a computational model to examine three important factors hypothesized to influence the loads experienced by vertebrae in the neck under compressive impact: muscle activation, torso constraints, and pre-flexion angle of the cervical spine. Since cadaver testing is not practical for large scale parametric analyses, these factors were studied using a previously validated computational model. On average, simulations with active muscles had 32% larger compressive forces and 25% larger shear forces-well in excess of what was expected from the muscle forces alone. In the short period of time required for neck injury, constraints on torso motion increased the average neck compression by less than 250N. The pre-flexion hypothesis was tested by examining pre-flexion angles from neutral (0°) to 64°. Increases in pre-flexion resulted in the largest increases in peak loads and the expression of higher-order buckling modes. Peak force and buckling modality were both very sensitive to pre-flexion angle. These results validate the relevance of prior cadaver models for neck injury and help explain the wide variety of cervical spine fractures that can result from ostensibly similar compressive loadings. They also give insight into the mechanistic differences between burst fractures and lower cervical spine dislocations.

  11. Are static and dynamic kinematics comparable after total knee arthroplasty?

    Science.gov (United States)

    Saevarsson, Stefan K; Romeo, Carolina I; Anglin, Carolyn

    2013-04-05

    Knee kinematics provide information about how the femoral, tibial and patellar bones or prosthetic components move relative to each other. Accurate knowledge of kinematics is valuable for implant design, comparisons between designs or surgical techniques, and to identify differences between patients with good and poor outcomes. Both static and dynamic imaging techniques have been used to evaluate kinematics. In general, static imaging is used to capture better quality images or to capture views that cannot be acquired by dynamic imaging, whereas dynamic imaging is used to capture real-life movements. How well static kinematics represent dynamic kinematics is subject to frequent debate and has not been adequately addressed, especially after total knee arthroplasty (TKA). We compared the static and dynamic weightbearing kinematics of 10 female subjects after TKA. Using the same clinical scanner for both methods, static images were taken using our standard protocol, sequential-biplane radiographs at multiple flexion angles, as well as with dynamic video fluoroscopy during a step up activity. The static method can reliably measure all 12 degrees of freedom (DOF) after TKA, however only seven were compared due to the poorer out-of-plane reliability in the single-plane dynamic imaging. No differences were found between the static and dynamic kinematics for nine out of ten subjects. For one subject, however, a difference of 5-8° in internal/external tibial rotation was found. The research question, study purpose and the advantages and disadvantages of each method need to be considered when determining which imaging method to use.

  12. Modulation of constitutive activity and signaling bias of the ghrelin receptor by conformational constraint in the second extracellular loop

    DEFF Research Database (Denmark)

    Mokrosinski, Jacek; Frimurer, Thomas M; Sivertsen, Bjoern

    2012-01-01

    phenotypes as the negatively charged Glu residue. Computational chemistry analysis indicated that the propensity for the C-terminal segment of ECL2b to form an extended a-helix was increased from 15% in the wild type to 89% and 82% by introduction in position 204(C+6) of a Glu or a Lys residue, respectively....... Moreover, the constitutive activity of the receptor was inhibited by Zn(2+) binding in an engineered metal-ion site stabilizing an a-helical conformation of this loop segment. It is concluded that the high constitutive activity of the ghrelin receptor is dependent upon flexibility in the C-terminal segment...

  13. Real time markerless motion tracking using linked kinematic chains

    Science.gov (United States)

    Luck, Jason P.; Small, Daniel E.

    2007-08-14

    A markerless method is described for tracking the motion of subjects in a three dimensional environment using a model based on linked kinematic chains. The invention is suitable for tracking robotic, animal or human subjects in real-time using a single computer with inexpensive video equipment, and does not require the use of markers or specialized clothing. A simple model of rigid linked segments is constructed of the subject and tracked using three dimensional volumetric data collected by a multiple camera video imaging system. A physics based method is then used to compute forces to align the model with subsequent volumetric data sets in real-time. The method is able to handle occlusion of segments and accommodates joint limits, velocity constraints, and collision constraints and provides for error recovery. The method further provides for elimination of singularities in Jacobian based calculations, which has been problematic in alternative methods.

  14. Classical Nonminimal Lagrangians and Kinematic Tests of Special Relativity

    CERN Document Server

    Schreck, M

    2016-01-01

    This article gives a brief summary on recently obtained classical lagrangians for the nonminimal fermion sector of the Standard-Model Extension (SME). Such lagrangians are adequate descriptions of classical particles that are subject to a Lorentz-violating background field based on the SME. Explicitly, lagrangians were obtained for the leading nonminimal contributions of the m, a, c, e, and f coefficients. These results were then used to interpret classical, kinematic tests of Special Relativity in the framework of the nonminimal SME. This led to new constraints on certain nonminimal controlling coefficients. Although the experiments were very sophisticated in the era when they were carried out, their sensitivities for detecting Lorentz violation were still far away from the Planck scale. Obtaining the novel constraints can be considered as a proof-of-principle demonstrating the applicability of the classical lagrangians computed.

  15. Multi-joint movements with reversal in Parkinson's disease: Kinematics and electromyography.

    Science.gov (United States)

    Sande de Souza, Luciane Aparecida Pascucci; Dionísio, Valdeci Carlos; Almeida, Gil Lúcio

    2011-04-01

    Subjects with Parkinson's disease (PD) presented difficulties in the performance of multi-joint movements. The purpose of the study was to determine whether the slowness of such movements was caused by the generation of non-linear trajectories and/or by a reduction or a deficit in the modulation of EMG activity. Nine healthy subjects and 10 subjects with PD performed multi-joint movements involving elbow and shoulder with reversal towards three targets in the sagittal plane without any constraint. The movement kinematics were calculated using X and Y coordinates of the markers positioned on the joints. EMG signals were recorded for the muscles related to these movements. The results revealed that subjects with PD presented a lower linear speed and the differences between them and healthy subjects increased with target distance. The trajectory was found to be linear and both groups of subjects had few errors in the targets despite the slower muscle activity in subjects with PD. Another interesting finding was the EMG pattern of subjects with PD. They showed a difficulty in modulating the activity of agonists and antagonists during the different movement phases. The low speed movements of PD subjects were attributable to the low EMG activity and difficulty in modulating the bursts of muscle activity.

  16. Kinematic characteristics of postural control during reaching in preterm children with cerebral palsy

    NARCIS (Netherlands)

    Van Der Heide, JC; Folk, JM; Otten, B; Stremmelaar, E; Hadders-Algra, M

    2005-01-01

    The relationships between kinematic characteristics of sitting posture during reaching movements of the dominant arm and I) the kinematics of the reaching movement itself and 2) functional performance during daily life activities (PEDI) were assessed in 51 sitting preterm children with cerebral pals

  17. Algebraic analysis of kinematics of multibody systems

    Directory of Open Access Journals (Sweden)

    S. Piipponen

    2013-02-01

    Full Text Available The constructive commutative algebra is very useful in the kinematical analysis of the mechanisms because a large class of systems can be described using polynomial equations. We show that one can analyze quite complicated systems using a sort of divide and conquer strategy to decompose the system, and hence the configuration space, into simpler parts. The key observation is that it seems that typically systems indeed have a lot of distinct components, but usually only one of them is physically relevant. Hence if one finds the equations describing the component of interest the analysis of this system can be surprisingly simple compared to the original system. In particular typically the possible singularities of the original system disappear when one restricts the attention to the relevant component. On the technical side we show that some basic constraints used to define joints in 3 dimensional mechanisms can be decomposed to simpler parts. This has significant practical consequences because using these fundamental decompositions when writing the equations for complicated mechanisms decreases dramatically the complexity of the required computations.

  18. Dynamics and causality constraints in field theory

    CERN Document Server

    De Souza, M M

    1997-01-01

    We discuss the physical meaning and the geometric interpretation of causality implementation in classical field theories. Causality is normally implemented through kinematical constraints on fields but we show that in a zero-distance limit they also carry a dynamical information, which calls for a revision of our standard concepts of interacting fields. The origin of infinities and other inconsistencies in field theories is traced to fields defined with support on the lightcone; a finite and consistent field theory requires a lightcone generator as the field support.

  19. SUMOylation Is an Inhibitory Constraint that Regulates the Prion-like Aggregation and Activity of CPEB3

    Directory of Open Access Journals (Sweden)

    Bettina Drisaldi

    2015-06-01

    Full Text Available Protein synthesis is crucial for the maintenance of long-term-memory-related synaptic plasticity. The prion-like cytoplasmic polyadenylation element-binding protein 3 (CPEB3 regulates the translation of several mRNAs important for long-term synaptic plasticity in the hippocampus. Here, we provide evidence that the prion-like aggregation and activity of CPEB3 is controlled by SUMOylation. In the basal state, CPEB3 is a repressor and is soluble. Under these circumstances, CPEB3 is SUMOylated in hippocampal neurons both in vitro and in vivo. Following neuronal stimulation, CPEB3 is converted into an active form that promotes the translation of target mRNAs, and this is associated with a decrease of SUMOylation and an increase of aggregation. A chimeric CPEB3 protein fused to SUMO cannot form aggregates and cannot activate the translation of target mRNAs. These findings suggest a model whereby SUMO regulates translation of mRNAs and structural synaptic plasticity by modulating the aggregation of the prion-like protein CPEB3.

  20. Exploring MaNGA's kinematic maps

    Science.gov (United States)

    Weijmans, Anne-Marie; MaNGA Team

    2016-01-01

    Different galaxy formation processes leave different imprints on the gas and stellar kinematic patterns for a galaxy. With MaNGA, we now have after one year of observations an unprecedented sample of 1400 nearby galaxies for which we can study gas and stellar kinematics in much detail, based on integral-field spectroscopy. We are measuring kinematic quantities such as LambdaR (angular momentum) and their (possible) correlations with other galaxy properties such as mass, morphology and environment. By quantifying the kinematic (sub)structures in velocity and dispersion maps, we will construct a kinematic galaxy classification that can be linked to their formation processes.

  1. A kinematic comparison of alterations to knee and ankle angles from resting measures to active pedaling during a graded exercise protocol.

    Science.gov (United States)

    Peveler, Willard W; Shew, Brandy; Johnson, Samantha; Palmer, Thomas G

    2012-11-01

    Saddle height is one of the most researched areas of bike fit. The current accepted method for adjusting saddle height involves the use of a goniometer to adjust saddle height so that a knee angle between 25° and 35° is obtained. This measurement is taken while the cyclist maintains a static position with the pedal at the 6-o'-clock position. However, the act of pedaling is dynamic, and angles may alter during movement. The purpose of this study was to examine the alterations to knee and ankle angle occurring from static measures to active pedaling across intensities experienced by cyclists during a graded exercise protocol. Thirty-four recreational to highly trained cyclists were evaluated using 2D analysis of stationary position and 3 active levels (level 1, respiratory exchange ratio of 1.00, and max). Dependent measures were compared using repeated measures analysis of variance (p = 0.05). When examining the results, it is evident that significant alterations to pedal stroke occur from stationary measures to active pedaling and as intensity increases toward maximal. Plantar flexion increased when moving from stationary measures to active pedaling, which resulted in an increase in knee angle. Although still greater than stationary measures, less plantar flexion occurred at higher intensities when compared with lower intensity cycling. Less plantar flexion at higher intensities is most likely a result of application of a larger downward torque occurring because of greater power requirements at higher intensities. There appeared to be greater variability in angle when examining novice cyclists in relation to more experienced cyclists. Although stationary measures are where a bike fit session will begin, observation during the pedal cycle may be needed to fine-tune the riders' fit.

  2. Kinematic modeling, analysis and test on a quiet spherical pump

    Science.gov (United States)

    Guan, Dong; Wu, Jiu Hui; Jing, Li; Hilton, Harry H.; Lu, Kuan

    2016-11-01

    In this paper, design and modeling of a novel spherical pump are undertaken. Both sound and vibration properties of the pump are studied experimentally. The working mechanism of the pump is analyzed firstly, and then structural design and kinematic theory are modeled by using two different coordinate systems. Nonlinear kinematic constraint equations are developed using a generalized computational method for spatial kinematic analysis. These equations are solved to yield the displacement, angular velocity and acceleration properties of motion parts with different structural parameters. Sound and vibration characteristics of the spherical pump and traditional solenoid pumps are studied experimentally at different rotating speeds of 1000, 1500, 2000, 2500 and 3000 rev/min. Results indicate that sound pressure levels of the proposed spherical are reduced to 40.7 dB(A), which are 11.1 dB(A) lower than the traditional solenoid pump's 51.8 dB(A) at the rated operating conditions. The sound spectra are analyzed in detail in order to investigate the causes, which are structural pattern and working mechanisms. The proposed spherical pump has many advantages and can be utilized as a substitute for other pumps in some special fields, such as hospital facilities and household appliances.

  3. Time-dependence between upper arm muscles activity during rapid movements: observation of the proportional effects predicted by the kinematic theory.

    Science.gov (United States)

    Plamondon, Réjean; Djioua, Moussa; Mathieu, Pierre A

    2013-10-01

    Rapid human movements can be assimilated to the output of a neuromuscular system with an impulse response modeled by a Delta-Lognormal equation. In such a model, the main assumption concerns the cumulative time delays of the response as it propagates toward the effector following a command. To verify the validity of this assumption, delays between bursts in electromyographic (EMG) signals of agonist and antagonist muscles activated during a rapid hand movement were investigated. Delays were measured between the surface EMG signals of six muscles of the upper limb during single rapid handwriting strokes. From EMG envelopes, regressions were obtained between the timing of the burst of activity produced by each monitored muscle. High correlation coefficients were obtained supporting the proportionality of the cumulative time delays, the basic hypothesis of the Delta-Lognormal model. A paradigm governing the sequence of muscle activities in a rapid movement could, in the long run, be useful for applications dealing with the analysis and synthesis of human movements.

  4. Constraints from atmospheric CO2 and satellite-based vegetation activity observations on current land carbon cycle trends

    Directory of Open Access Journals (Sweden)

    S. Zaehle

    2012-11-01

    Full Text Available Terrestrial ecosystem models used for Earth system modelling show a significant divergence in future patterns of ecosystem processes, in particular carbon exchanges, despite a seemingly common behaviour for the contemporary period. An in-depth evaluation of these models is hence of high importance to achieve a better understanding of the reasons for this disagreement. Here, we develop an extension for existing benchmarking systems by making use of the complementary information contained in the observational records of atmospheric CO2 and remotely-sensed vegetation activity to provide a firm set of diagnostics of ecosystem responses to climate variability in the last 30 yr at different temporal and spatial scales. The selection of observational characteristics (traits specifically considers the robustness of information given the uncertainties in both data and evaluation analysis. In addition, we provide a baseline benchmark, a minimum test that the model under consideration has to pass, to provide a more objective, quantitative evaluation framework. The benchmarking strategy can be used for any land surface model, either driven by observed meteorology or coupled to a climate model. We apply this framework to evaluate the offline version of the MPI-Earth system model's land surface scheme JSBACH. We demonstrate that the complementary use of atmospheric CO2 and satellite based vegetation activity data allows to pinpoint specific model failures that would not be possible by the sole use of atmospheric CO2 observations.

  5. Kinematic Fitting of Detached Vertices

    Energy Technology Data Exchange (ETDEWEB)

    Mattione, Paul [Rice Univ., Houston, TX (United States)

    2007-05-01

    The eg3 experiment at the Jefferson Lab CLAS detector aims to determine the existence of the $\\Xi_{5}$ pentaquarks and investigate the excited $\\Xi$ states. Specifically, the exotic $\\Xi_{5}^{--}$ pentaquark will be sought by first reconstructing the $\\Xi^{-}$ particle through its weak decays, $\\Xi^{-}\\to\\pi^{-}\\Lambda$ and $\\Lambda\\to\\pi^{-}$. A kinematic fitting routine was developed to reconstruct the detached vertices of these decays, where confidence level cuts on the fits are used to remove background events. Prior to fitting these decays, the exclusive reaction $\\gamma D\\rightarrow pp\\pi^{-}$ was studied in order to correct the track measurements and covariance matrices of the charged particles. The $\\Lambda\\rightarrow p\\pi^{-}$ and $\\Xi^{-}\\to\\pi^{-}\\Lambda$ decays were then investigated to demonstrate that the kinematic fitting routine reconstructs the decaying particles and their detached vertices correctly.

  6. Sex Differences in Tibiocalcaneal Kinematics

    Directory of Open Access Journals (Sweden)

    Sinclair Jonathan

    2014-08-01

    Full Text Available Purpose. Female runners typically suffer more from chronic running injuries than age-matched males, although the exact biome-chanical mechanisms behind the increased susceptibility of female runners are unknown. This study aimed to compare sex differences in tibiocalcaneal kinematics during the stance phase of running. Methods. Twenty male and twenty female participants ran at 4.0 m · s–1. Tibiocalcaneal kinematics were measured using an eight-camera motion analysis system and compared using independent samples t tests. Results. Peak eversion and tibial internal rotation angles were shown to be significantly greater in female runners. Conclusions. based on these observations, it was determined that female runners may be at increased risk from chronic injury development in relation to excessive tibiocalcaneal motions in the coronal and transverse planes.

  7. Measurement of reed valve kinematics

    Directory of Open Access Journals (Sweden)

    Fenkl Michael

    2016-01-01

    Full Text Available The measurement of key kinematic parameters of a reed valve movement is necessary for the further development of the reed valve system. These parameters are dependent on the geometry and material properties of the valve. As they directly affect the quantity of air flowing around the valve, a simple and easy to implement measurement of various valve configuration based on the air flow has been devised and is described in this paper, along with its technical parameters and drawbacks when evaluating reed valves used in reciprocating air compressors. Results are presented for a specimen of a compressor under examination. All kinematic parameters, and timing of the opening and closing of the valve, obtained from the measurement are presented and discussed.

  8. Measurement of reed valve kinematics

    Science.gov (United States)

    Fenkl, Michael; Dvořák, Václav; Vít, Tomáš

    2016-03-01

    The measurement of key kinematic parameters of a reed valve movement is necessary for the further development of the reed valve system. These parameters are dependent on the geometry and material properties of the valve. As they directly affect the quantity of air flowing around the valve, a simple and easy to implement measurement of various valve configuration based on the air flow has been devised and is described in this paper, along with its technical parameters and drawbacks when evaluating reed valves used in reciprocating air compressors. Results are presented for a specimen of a compressor under examination. All kinematic parameters, and timing of the opening and closing of the valve, obtained from the measurement are presented and discussed.

  9. Pythagoras Theorem and Relativistic Kinematics

    Science.gov (United States)

    Mulaj, Zenun; Dhoqina, Polikron

    2010-01-01

    In two inertial frames that move in a particular direction, may be registered a light signal that propagates in an angle with this direction. Applying Pythagoras theorem and principles of STR in both systems, we can derive all relativistic kinematics relations like the relativity of simultaneity of events, of the time interval, of the length of objects, of the velocity of the material point, Lorentz transformations, Doppler effect and stellar aberration.

  10. Kinematics of the Danakil microplate

    OpenAIRE

    2002-01-01

    A refinement and extrapolation of recent motion estimates for the Danakilmicroplate, based on ancient kinematic indicators in the Afar region, describesthe evolution of a microplate in the continental realm. The Danakil horst is anelevated part of this microplate, exposing Precambrian basement within theAfar depression, site of the Nubia-Somalia-Arabia triple junction. We compareevidence for strike- or oblique-slip faults in data from the Afar depression andsouthern Red Sea to small circles a...

  11. The Soft Cumulative Constraint

    CERN Document Server

    Petit, Thierry

    2009-01-01

    This research report presents an extension of Cumulative of Choco constraint solver, which is useful to encode over-constrained cumulative problems. This new global constraint uses sweep and task interval violation-based algorithms.

  12. Submarine explosive activity and ocean noise generation at Monowai Volcano, Kermadec Arc: constraints from hydroacoustic T-waves

    Science.gov (United States)

    Grevemeyer, Ingo; Metz, Dirk; Watts, Anthony

    2016-04-01

    Submarine volcanic activity is difficult to detect, because eruptions at depth are strongly attenuated by seawater. With increasing depth the ambient water pressure increases and limits the expansion of gas and steam such that volcanic eruptions tend to be less violent and less explosive with depth. Furthermore, the thermal conductivity and heat capacity of water causes rapid cooling of ejected products and hence erupted magma cools much more quickly than during subaerial eruptions. Therefore, reports on submarine volcanism are restricted to those sites where erupted products - like the presence of pumice rafts, gas bubbling on the sea surface, and local seawater colour changes - reach the sea surface. However, eruptions cause sound waves that travel over far distances through the Sound-Fixing-And-Ranging (SOFAR) channel, so called T-waves. Seismic networks in French Polynesia recorded T-waves since the 1980's that originated at Monowai Volcano, Kermadec Arc, and were attributed to episodic growth and collapse events. Repeated swath-mapping campaigns conducted between 1998 and 2011 confirm that Monowai volcano is a highly dynamic volcano. In July of 2007 a network of ocean-bottom-seismometers (OBS) and hydrophones was deployed and recovered at the end of January 2008. The instruments were located just to the east of Monowai between latitude 25°45'S and 27°30'S. The 23 OBS were placed over the fore-arc and on the incoming subducting plate to obtain local seismicity associated with plate bending and coupling of the subduction megathrust. However, we recognized additional non-seismic sleuths in the recordings. Events were best seen in 1 Hz high-pass filtered hydrophone records and were identified as T-waves. The term T-wave is generally used for waves travelling through the SOFAR channel over large distances. In our case, however, they were also detected on station down to ~8000 m, suggesting that waves on the sea-bed station were direct waves caused by explosive

  13. Methodological constraints in interpreting serum paraoxonase-1 activity measurements: an example from a study in HIV-infected patients

    Directory of Open Access Journals (Sweden)

    Joven Jorge

    2010-03-01

    Full Text Available Abstract Background Paraoxonase-1 (PON1 is an antioxidant enzyme that attenuates the production of the monocyte chemoattractant protein-1 (MCP-1 in vitro. Although oxidation and inflammation are closely related processes, the association between PON1 and MCP-1 has not been completely characterised due, probably, to that the current use of synthetic substrates for PON1 measurement limits the interpretation of the data. In the present study, we explored the relationships between the circulating levels of PON1 and MCP-1 in human immunodeficiency virus-infected patients in relation to the multifunctional capabilities of PON1. Methods We measured selected variables in 227 patients and in a control group of 409 participants. Serum PON1 esterase and lactonase activities were measured as the rates of hydrolysis of paraoxon and of 5-(thiobutyl-butyrolactone, respectively. Oxidised LDL and MCP-1 concentrations were determined by enzyme-linked immunosorbent assay. High-density lipoproteins cholesterol, apolipoprotein A-I, and C-reactive protein concentrations were measured by standard automated methods. Results There were significant relationships between PON1 activity and several indices of oxidation and inflammation in control subjects and in infected patients. However, these relationships varied not only with disease status but also on the type of substrate used for PON1 measurement. Conclusion The present study is a cautionary tale highlighting that results of clinical studies on PON1 may vary depending on the methods used as well as the disease studied. Until more specific methods using physiologically-akin substrates are developed for PON1 measurement, we suggest the simultaneous employment of at least two different substrates in order to improve the reliability of the results obtained.

  14. Constraints on Alpine hydrothermal activity and deformation from U-Th-Pb dating of cleft monazite and xenotime (Western Alps)

    Science.gov (United States)

    Grand'Homme, Alexis; Janots, Emilie; Bosse, Valerie; Seydoux-Guillaume, Anne-Magali; De Ascencao, Roger

    2016-04-01

    In this large-scale regional study, age of hydrothermal monazite (and xenotime) precipitation has been investigated through in-situ U-Th-Pb dating of crystals collected in 11 clefts (veins) taken in the internal and external massifs (Western Alps). The investigated clefts are composed of quartz, chlorite (± epidote), albite and millimetric accessory minerals (monazite, apatite, xenotime, anatase, rutile). Prior to dating, cleft monazite composition was thoroughly studied to reveal potential zoning. In-situ dating through different compositional domains of single monazite crystal yields well-resolved Th-Pb ages (typically with 0.1-0.3 Ma resolution) indicating for growth episodes with short duration. Comparison of U-Pb and Th-Pb dating indicates that the U-Pb systematics appears successful to date cleft monazite with low Th/U ratio (typically hand, monazite dating in the Argentera (20.6 ± 0.3 Ma) confirms for the regional diachronism observed from South to the North of the ECM in the Western Alps. First ages were here obtained for the hydrothermal activity of the internal massifs of the Western Alps. As expected from other (thermo)chronometers, hydrothermal activity in the Internal Alpine domains (Briançonnais) is older than in the ECM. In the Briançonnais zone, monazite age at 32.1 ± 0.2 Ma coincides with the exhumation along the penninic front. In the second cleft, monazite age at 23.3 ± 0.2 Ma is more complex to attribute to a specific deformation stage.

  15. Kinematic Downsizing at z~2

    CERN Document Server

    Simons, Raymond C; Trump, Jonathan R; Weiner, Benjamin J; Heckman, Timothy M; Barro, Guillermo; Koo, David C; Guo, Yicheng; Pacifici, Camilla; Koekemoer, Anton; Stephens, Andrew W

    2016-01-01

    We present results from a survey of the internal kinematics of 49 star-forming galaxies at z$\\,\\sim\\,$2 in the CANDELS fields with the Keck/MOSFIRE spectrograph (SIGMA, Survey in the near-Infrared of Galaxies with Multiple position Angles). Kinematics (rotation velocity $V_{rot}$ and integrated gas velocity dispersion $\\sigma_g$) are measured from nebular emission lines which trace the hot ionized gas surrounding star-forming regions. We find that by z$\\,\\sim\\,$2, massive star-forming galaxies ($\\log\\,M_*/M_{\\odot}\\gtrsim10.2$) have assembled primitive disks: their kinematics are dominated by rotation, they are consistent with a marginally stable disk model, and they form a Tully-Fisher relation. These massive galaxies have values of $V_{rot}/\\sigma_g$ which are factors of 2-5 lower than local well-ordered galaxies at similar masses. Such results are consistent with findings by other studies. We find that low mass galaxies ($\\log\\,M_*/M_{\\odot}\\lesssim10.2$) at this epoch are still in the early stages of disk...

  16. Activation and application of an obligatory phonotactic constraint in German during automatic speech processing is revealed by human event-related potentials.

    Science.gov (United States)

    Steinberg, Johanna; Truckenbrodt, Hubert; Jacobsen, Thomas

    2010-07-01

    In auditory speech processing, implicit linguistic knowledge is activated and applied on phonetic and segment-related phonological processing level even if the perceived sound sequence is outside the focus of attention. In this study, the effects of language-specific phonotactic restrictions on pre-attentive auditory speech processing were investigated, using the Mismatch Negativity component of the human event-related brain potential. In German grammar, the distribution of the velar and the palatal dorsal fricative is limited by an obligatory phonotactic constraint, Dorsal Fricative Assimilation, which demands that a vowel and a following dorsal fricative must have the same specifications for articulatory backness. For passive oddball stimulation, we used three phonotactically correct VC syllables and one incorrect VC syllable, composed of the vowels [epsilon] and [open o] and the fricatives [ç] and []. Stimuli were contrasted pairwise in experimental oddball blocks in a way that they differed in regard to their respective vowel but shared the fricative. Additionally to the usual Mismatch Negativity which is attributable to the change of the initial vowel and which was elicited by all deviants, we observed a second negative deflection in the deviant ERP elicited by the phonotactically ill-formed syllable only. This negativity cannot be attributed to any acoustical or phonemic difference between standard and deviant, it rather reflects the effect of a phonotactic evaluation process after both sounds of the syllable were identified. Our finding suggests that implicit phonotactic knowledge is activated and applied even outside the focus of the participants' attention.

  17. Geochemical constraints on the diversity and activity of H2 -oxidizing microorganisms in diffuse hydrothermal fluids from a basalt- and an ultramafic-hosted vent.

    Science.gov (United States)

    Perner, Mirjam; Petersen, Jillian M; Zielinski, Frank; Gennerich, Hans-Hermann; Seifert, Richard

    2010-10-01

    Mixing processes of reduced hydrothermal fluids with oxygenated seawater and fluid-rock reactions contribute to the chemical signatures of diffuse venting and likely determine the geochemical constraints on microbial life. We examined the influence of fluid chemistry on microbial diversity and activity by sampling diffuse fluids emanating through mussel beds at two contrasting hydrothermal vents. The H(2) concentration was very low at the basalt-hosted Clueless site, and mixing models suggest O(2) availability throughout much of the habitat. In contrast, effluents from the ultramafic-hosted Quest site were considerably enriched in H(2) , while O(2) is likely limited to the mussel layer. Only two different hydrogenase genes were identified in clone libraries from the H(2) -poor Clueless fluids, but these fluids exhibited the highest H(2) uptake rates in H(2) -spiked incubations (oxic conditions, at 18 °C). In contrast, a phylogenetically diverse H(2) -oxidizing potential was associated with distinct thermal conditions in the H(2) -rich Quest fluids, but under oxic conditions, H(2) uptake rates were extremely low. Significant stimulation of CO(2) fixation rates by H(2) addition was solely illustrated in Quest incubations (P-value <0.02), but only in conjunction with anoxic conditions (at 18 °C). We conclude that the factors contributing toward differences in the diversity and activity of H(2) oxidizers at these sites include H(2) and O(2) availability.

  18. Kinematic Characteristics of 3-UPU Parallel Manipulator in Singularity and Its Application

    Directory of Open Access Journals (Sweden)

    Peng Binbin

    2011-09-01

    Full Text Available This paper focuses on the kinematic characteristics of the 3‐UPU (universal‐prismatic‐ universal parallel manipulator in one of singular configurations. The motion of the moving platform is analyzed by changing the layout of the universal joints. A layout of universal joints in the singular configuration is discussed in detail by deriving the kinematic and constraint equations. Solving the equations, the kinematic characteristics in such case is obtained. At the same time the kinematic characteristics is simulated by the commercial software and the results of the simulation verify it. Based on the kinematics characteristics of it, the application of the singular configuration is presented. And a compound limb which can translate freely along a circular path is presented. Finally, the some new 2‐DOF (degree of freedom planar parallel translating manipulators whose orientation can remain constant are put forward by the compound limb. The passive joints of the new 2‐DOF planar parallel translating manipulators are universal joint and the struts of it do not bear the bending moment. It gives the planar parallel manipulator a good architecture to resist the force which is perpendicular to the kinematics plane.

  19. Composing constraint solvers

    NARCIS (Netherlands)

    Zoeteweij, P.

    2005-01-01

    Composing constraint solvers based on tree search and constraint propagation through generic iteration leads to efficient and flexible constraint solvers. This was demonstrated using OpenSolver, an abstract branch-and-propagate tree search engine that supports a wide range of relevant solver configu

  20. Analysis and experimental kinematics of a skid-steering wheeled robot based on a laser scanner sensor.

    Science.gov (United States)

    Wang, Tianmiao; Wu, Yao; Liang, Jianhong; Han, Chenhao; Chen, Jiao; Zhao, Qiteng

    2015-04-24

    Skid-steering mobile robots are widely used because of their simple mechanism and robustness. However, due to the complex wheel-ground interactions and the kinematic constraints, it is a challenge to understand the kinematics and dynamics of such a robotic platform. In this paper, we develop an analysis and experimental kinematic scheme for a skid-steering wheeled vehicle based-on a laser scanner sensor. The kinematics model is established based on the boundedness of the instantaneous centers of rotation (ICR) of treads on the 2D motion plane. The kinematic parameters (the ICR coefficient , the path curvature variable and robot speed ), including the effect of vehicle dynamics, are introduced to describe the kinematics model. Then, an exact but costly dynamic model is used and the simulation of this model's stationary response for the vehicle shows a qualitative relationship for the specified parameters and . Moreover, the parameters of the kinematic model are determined based-on a laser scanner localization experimental analysis method with a skid-steering robotic platform, Pioneer P3-AT. The relationship between the ICR coefficient and two physical factors is studied, i.e., the radius of the path curvature and the robot speed . An empirical function-based relationship between the ICR coefficient of the robot and the path parameters is derived. To validate the obtained results, it is empirically demonstrated that the proposed kinematics model significantly improves the dead-reckoning performance of this skid-steering robot.

  1. Feedback between erosion and active deformation: geomorphic constraints from the frontal Jura fold-and-thrust belt (eastern France)

    Science.gov (United States)

    Madritsch, Herfried; Fabbri, Olivier; Hagedorn, Eva-Marie; Preusser, Frank; Schmid, Stefan M.; Ziegler, Peter A.

    2010-10-01

    A regional tectono-geomorphic analysis indicates a Pliocene to recent rock uplift of the outermost segment of the Jura fold-and-thrust belt, which spatially coincides with the intra-continental Rhine-Bresse Transfer Zone. Elevated remnants of the partly eroded Middle Pliocene Sundgau-Forêt de Chaux Gravels identified by heavy mineral analyses allow for a paleo-topographic reconstruction that yields minimum regional Latest Pliocene to recent rock uplift rates of 0.05 ± 0.02 mm/year. This uplift also affected the Pleistocene evolution of the Ognon and Doubs drainage basins and is interpreted as being tectonically controlled. While the Ognon River was deflected from the uplifted region the Doubs deeply incised into it. Focused incision of the Doubs possibly sustained ongoing deformation along anticlines which were initiated during the Neogene evolution of the thin-skinned Jura fold-and-thrust belt. At present, this erosion-related active deformation is taking place synchronously with thick-skinned tectonics, controlling the inversion of the Rhine-Bresse Transfer Zone. This suggests local decoupling between seismogenic basement faulting and erosion-related deformation of the Mesozoic cover sequences.

  2. Differences in unilateral chest press muscle activation and kinematics on a stable versus unstable surface while holding one versus two dumbbells.

    Science.gov (United States)

    Patterson, Jeffrey M; Vigotsky, Andrew D; Oppenheimer, Nicole E; Feser, Erin H

    2015-01-01

    Training the bench press exercise on a traditional flat bench does not induce a level of instability as seen in sport movements and activities of daily living. Twenty participants were recruited to test two forms of instability: using one dumbbell rather than two and lifting on the COR bench compared to a flat bench. Electromyography (EMG) amplitudes of the pectoralis major, middle trapezius, external oblique, and internal oblique were recorded and compared. Differences in range of motion (ROM) were evaluated by measuring an angular representation of the shoulder complex. Four separate conditions of unilateral bench press were tested while lifting on a: flat bench with one dumbbell, flat bench with two dumbbells, COR Bench with one dumbbell, and COR Bench with two dumbbells. The results imply that there are no differences in EMG amplitude or ROM between the COR bench and traditional bench. However, greater ROM was found to be utilized in the single dumbbell condition, both in the COR bench and the flat bench.

  3. Differences in unilateral chest press muscle activation and kinematics on a stable versus unstable surface while holding one versus two dumbbells

    Directory of Open Access Journals (Sweden)

    Jeffrey M. Patterson

    2015-10-01

    Full Text Available Training the bench press exercise on a traditional flat bench does not induce a level of instability as seen in sport movements and activities of daily living. Twenty participants were recruited to test two forms of instability: using one dumbbell rather than two and lifting on the COR bench compared to a flat bench. Electromyography (EMG amplitudes of the pectoralis major, middle trapezius, external oblique, and internal oblique were recorded and compared. Differences in range of motion (ROM were evaluated by measuring an angular representation of the shoulder complex. Four separate conditions of unilateral bench press were tested while lifting on a: flat bench with one dumbbell, flat bench with two dumbbells, COR Bench with one dumbbell, and COR Bench with two dumbbells. The results imply that there are no differences in EMG amplitude or ROM between the COR bench and traditional bench. However, greater ROM was found to be utilized in the single dumbbell condition, both in the COR bench and the flat bench.

  4. Polarimetric Observations of 15 Active Galactic Nuclei at High Frequencies: Jet Kinematics from Bimonthly Monitoring with the Very Long Baseline Array

    CERN Document Server

    Jorstad, S G; Lister, M L; Stirling, A M; Cawthorne, T V; Gear, W K; Gómez, J L; Stevens, J A; Smith, P S; Forster, J R; Gabuzda, D C; Robson, E I; Jorstad, Svetlana G.; Marscher, Alan P.; Lister, Matthew L.; Stirling, Alastair M.; Cawthorne, Timothy V.; Gear, Walter K.; Gomez, Jose L.; Stevens, Jason A.; Smith, Paul S.; Forster, James R.; Gabuzda, Denise C.

    2005-01-01

    We present total and polarized intensity images of 15 active galactic nuclei obtained with the Very Long Baseline Array at 7 mm at 17 epochs from 1998 March to 2001 April. At some epochs the images are accompanied by nearly simultaneous polarization measurements at 3 mm, 1.35/0.85 mm, and optical wavelengths. Here we analyze the 7 mm images to define the properties of the jets of two radio galaxies, five BL Lac objects, and eight quasars on angular scales $\\gtrsim 0.1$ milliarcseconds. We determine the apparent velocities of 109 features in the jets; for many of the features we derive Doppler factors using a new method based on comparison of timescale of decline in flux density with the light-travel time across the emitting region. This allows us to estimate the Lorentz factors, intrinsic brightness temperatures, and viewing angles of 77 superluminal knots, as well as the opening angle of the jet for each source. We analyze the derived physical parameters of the jets. In nine sources we detect statistically m...

  5. On Testing Constraint Programs

    CERN Document Server

    Lazaar, Nadjib; Yahia, Lebbah

    2010-01-01

    The success of several constraint-based modeling languages such as OPL, ZINC, or COMET, appeals for better software engineering practices, particularly in the testing phase. This paper introduces a testing framework enabling automated test case generation for constraint programming. We propose a general framework of constraint program development which supposes that a first declarative and simple constraint model is available from the problem specifications analysis. Then, this model is refined using classical techniques such as constraint reformulation, surrogate and global constraint addition, or symmetry-breaking to form an improved constraint model that must be thoroughly tested before being used to address real-sized problems. We think that most of the faults are introduced in this refinement step and propose a process which takes the first declarative model as an oracle for detecting non-conformities. We derive practical test purposes from this process to generate automatically test data that exhibit no...

  6. A Concept for Extending the Applicability of Constraint-Induced Movement Therapy through Motor Cortex Activity Feedback Using a Neural Prosthesis

    Directory of Open Access Journals (Sweden)

    Tomas E. Ward

    2007-01-01

    Full Text Available This paper describes a concept for the extension of constraint-induced movement therapy (CIMT through the use of feedback of primary motor cortex activity. CIMT requires residual movement to act as a source of feedback to the patient, thus preventing its application to those with no perceptible movement. It is proposed in this paper that it is possible to provide feedback of the motor cortex effort to the patient by measurement with near infrared spectroscopy (NIRS. Significant changes in such effort may be used to drive rehabilitative robotic actuators, for example. This may provide a possible avenue for extending CIMT to patients hitherto excluded as a result of severity of condition. In support of such a paradigm, this paper details the current status of CIMT and related attempts to extend rehabilitation therapy through the application of technology. An introduction to the relevant haemodynamics is given including a description of the basic technology behind a suitable NIRS system. An illustration of the proposed therapy is described using a simple NIRS system driving a robotic arm during simple upper-limb unilateral isometric contraction exercises with healthy subjects.

  7. Kinematical and EMG-classifications of a fencing attack.

    Science.gov (United States)

    Frère, J; Göpfert, B; Nüesch, C; Huber, C; Fischer, M; Wirz, D; Friederich, N F

    2011-01-01

    8 expert fencers were studied with a 3-dimensional motion analysis system. Each subject performed 10 flèche attacks toward a standardized target. Surface electromyography signals (EMG) were recorded of the deltoid pars clavicularis, infraspinatus and triceps brachii caput laterale muscles of the weapon arm. The recorded EMGs were averaged using EMG wavelet-transformation software. 4 phases were defined based on the arm kinematics and used to classify fencers into 2 groups. A first group of 4 fencers showed an early maximal elbow extension (Early MEE) whereas the second group presented a late maximal elbow extension (Late MEE). 2 EMG-classifications were based on this kinematical classification, one in the time-domain and the other in the frequency-domain by using the spherical classification. The time-domain EMG-classification showed a significantly ( P=0.03) higher normalized deltoid intensity for the Early MEE group (91 ± 18%) than the Late MEE group (36 ± 13%) in the attack phase. The spherical classification revealed that the activity of all the muscles was significantly classified (recognition rate 75%, P=0.04) between the 2 groups. This study of EMG and kinematics of the weapon upper limb in fencing proposes several classifications, which implies a relationship between kinematic strategies, muscular activations and fencing success.

  8. Kinematically complete chemical reaction dynamics

    Science.gov (United States)

    Trippel, S.; Stei, M.; Otto, R.; Hlavenka, P.; Mikosch, J.; Eichhorn, C.; Lourderaj, U.; Zhang, J. X.; Hase, W. L.; Weidemüller, M.; Wester, R.

    2009-11-01

    Kinematically complete studies of molecular reactions offer an unprecedented level of insight into the dynamics and the different mechanisms by which chemical reactions occur. We have developed a scheme to study ion-molecule reactions by velocity map imaging at very low collision energies. Results for the elementary nucleophilic substitution (SN2) reaction Cl- + CH3I → ClCH3 + I- are presented and compared to high-level direct dynamics trajectory calculations. Furthermore, an improved design of the crossed-beam imaging spectrometer with full three-dimensional measurement capabilities is discussed and characterization measurements using photoionization of NH3 and photodissociation of CH3I are presented.

  9. Calibration of a Parallel Kinematic Machine Tool

    Institute of Scientific and Technical Information of China (English)

    HE Xiao-mei; DING Hong-sheng; FU Tie; XIE Dian-huang; XU Jin-zhong; LI Hua-feng; LIU Hui-lin

    2006-01-01

    A calibration method is presented to enhance the static accuracy of a parallel kinematic machine tool by using a coordinate measuring machine and a laser tracker. According to the established calibration model and the calibration experiment, the factual 42 kinematic parameters of BKX-I parallel kinematic machine tool are obtained. By circular tests the comparison is made between the calibrated and the uncalibrated parameters and shows that there is 80% improvement in accuracy of this machine tool.

  10. Kinematical Analysis of an Articulated Mechanism

    CERN Document Server

    Fleischfresser, Luciano

    2015-01-01

    The purpose of this work is twofold: to present mathematical expressions for the kinematics of an articulated mechanism and to perform numerical experiments with the implemented Fortran code. The system of rigid parts is made of two slender bars and a disk. A constant 2 rad/s counterclockwise rotation rate is imposed on the disk triggering the planar motion of the longer bar (link) and the rotation of the shorter one (output). Angular relations, velocities and accelerations are analyzed for a 90-degree turn of the disk. The inversion of the linking bar sense of rotation is well captured by the simulation, and the paper and pencil solutions that may lead to wrong conclusions are explained. Equations are derived from first principles and the Fortran code is placed under version control (currently, v.0.8-beta). This computer project is relevant for those in charge of vector dynamics courses and wishing to expose students to project-based learning activities.

  11. Finite rotation and nonlinear beam kinematics

    Science.gov (United States)

    Hodges, Dewey H.

    1987-01-01

    Standard means of representing finite rotation in rigid-body kinematics, including orientation angles, Euler parameters, and Rodrigues parameters, are reviewed and compared. General kinematical relations for a beam theory that treats arbitrarily large rotation are then presented. The standard methods of representing finite rotations are applied to these kinematical expressions, and comparison is made among the standard methods and additional methods found in the literature, such as quasi-coordinates and linear combinations of projection angles. The method of Rodrigues parameters is shown to stand out for both its simplicity and generality when applied to beam kinematics, a result that is really missing from the literature.

  12. Active kinematics of the southern Red Sea

    Science.gov (United States)

    McClusky, S.; Reilinger, R.; Ogubazghi, G.; Amlesom, A.; Haileab, B.; Sholan, J.; Vernant, P.; Arrajehi, A.

    2009-04-01

    GPS measurements adjacent to the southern Red Sea and around the Afar Triple Junction (Red Sea Rift-Gulf of Aden Rift-East African Rift), indicate that the Red Sea rift bifurcates south of 16° N latitude with one branch following a continuation of the main Red Sea rift (~150° Azimuth) and the other oriented roughly N-S traversing the Danakil Depression/Afar volcanic province. These two rift branches account for the full Arabia-Nubia relative motion. Within the resolution of our observations, the partitioning of extension between rift branches varies linearly along strike; north of ~16°N extension (~15 mm/yr at 16°N) is confined to the main Red Sea rift while at the latitude of the Afar Triple Junction (~12°N) extension (~20 mm/yr) has transferred completely to the Danakil-Afar Depression. The Danakil block separates the two rifts and rotates counterclockwise, accommodating extension along the rifts and developing the triangular geometry of the Danakil/Afar Depression. Extrapolating the geodetic rates to the time of initial rifting of Arabia from Nubia (~25 ± 3 Ma) and estimating total extension across the rift branches from the present-day widths of the rifts suggests that Arabia-Nubia relative motion has been roughly constant since the initiation of Red Sea spreading, and that extension was initially confined to the main Red Sea rift with the presently observed bifurcation initiating at about 17 Ma.

  13. Constraints meet concurrency

    CERN Document Server

    Mauro, Jacopo

    2014-01-01

    This book describes the benefits that emerge when the fields of constraint programming and concurrency meet. On the one hand, constraints can be used in concurrency theory to increase the conciseness and the expressive power of concurrent languages from a pragmatic point of view. On the other hand, problems modeled by using constraints can be solved faster and more efficiently using a concurrent system. Both directions are explored providing two separate lines of development. Firstly the expressive power of a concurrent language is studied, namely Constraint Handling Rules, that supports constraints as a primitive construct. The features of this language which make it Turing powerful are shown. Then a framework is proposed to solve constraint problems that is intended to be deployed on a concurrent system. For the development of this framework the concurrent language Jolie following the Service Oriented paradigm is used. Based on this experience, an extension to Service Oriented Languages is also proposed in ...

  14. Canonical quantum gravity in the Vassiliev invariants arena; 1, Kinematical structure

    CERN Document Server

    Di Bartolo, C; Griego, J R; Pullin, J; Bartolo, Cayetano Di; Gambini, Rodolfo; Griego, Jorge; Pullin, Jorge

    2000-01-01

    We generalize the idea of Vassiliev invariants to the spin network context, with the aim of using these invariants as a kinematical arena for a canonical quantization of gravity. This paper presents a detailed construction of these invariants (both ambient and regular isotopic) requiring a significant elaboration based on the use of Chern-Simons perturbation theory which extends the work of Kauffman, Martin and Witten to four-valent networks. We show that this space of knot invariants has the crucial property -from the point of view of the quantization of gravity- of being loop differentiable in the sense of distributions. This allows the definition of diffeomorphism and Hamiltonian constraints. We show that the invariants are annihilated by the diffeomorphism constraint. In a companion paper we elaborate on the definition of a Hamiltonian constraint, discuss the constraint algebra, and show that the construction leads to a consistent theory of canonical quantum gravity.

  15. Kinematic analysis of rope skipper's stability

    Science.gov (United States)

    Ab Ghani, Nor Atikah; Rambely, Azmin Sham

    2014-06-01

    There are various kinds of jumping that can be done while performing rope skipping activity. This activity was always associated with injury. But, if the rope skipper can perform the activity in a right way, it is believed that the injury might be reduced. The main purpose of this paper is to observe the stability of rope skipper from a biomechanics perspective, which are the centre of mass, angle at the ankle, knee and hip joints and also the trajectory for the ipsilateral leg between the two types of skip which is one leg and two legs. Six healthy, physically active subject, two males and four females (age: 8.00±1.25 years, weight: 17.90±6.85 kg and height: 1.22±0.08 m) participated in this study. Kinematic data of repeated five cycles of rope skipping activity was captured by using Vicon Nexus system. Based on the data collected, skipping with two legs shows more stable behavior during preparation, flight and landing phases. It is concluded that landing on the balls of the feet, lowering the trajectory positions of the feet from the ground as well as flexion of each joint which would reduce the injury while landing.

  16. On Minimal Constraint Networks

    CERN Document Server

    Gottlob, Georg

    2011-01-01

    In a minimal binary constraint network, every tuple of a constraint relation can be extended to a solution. It was conjectured that computing a solution to such a network is NP complete. We prove this conjecture true and show that the problem remains NP hard even in case the total domain of all values that may appear in the constraint relations is bounded by a constant.

  17. Temporal Concurrent Constraint Programming

    DEFF Research Database (Denmark)

    Nielsen, Mogens; Valencia Posso, Frank Dan

    2002-01-01

    The ntcc calculus is a model of non-deterministic temporal concurrent constraint programming. In this paper we study behavioral notions for this calculus. In the underlying computational model, concurrent constraint processes are executed in discrete time intervals. The behavioral notions studied...... reflect the reactive interactions between concurrent constraint processes and their environment, as well as internal interactions between individual processes. Relationships between the suggested notions are studied, and they are all proved to be decidable for a substantial fragment of the calculus...

  18. Cortical Decoding of Individual Finger and Wrist Kinematics for an Upper-Limb Neuroprosthesis

    OpenAIRE

    Aggarwal, Vikram; Tenore, Francesco; Acharya, Soumyadipta; Schieber, Marc H.; Thakor, Nitish V.

    2009-01-01

    Previous research has shown that neuronal activity can be used to continuously decode the kinematics of gross movements involving arm and hand trajectory. However, decoding the kinematics of fine motor movements, such as the manipulation of individual fingers, has not been demonstrated. In this study, single unit activities were recorded from task-related neurons in M1 of two trained rhesus monkey as they performed individuated movements of the fingers and wrist. The primates’ hand was placed...

  19. Kinematics of the South Atlantic rift

    Directory of Open Access Journals (Sweden)

    C. Heine

    2013-01-01

    Full Text Available The South Atlantic rift basin evolved as branch of a large Jurassic-Cretaceous intraplate rift zone between the African and South American plates during the final breakup of western Gondwana. While the relative motions between South America and Africa for post-breakup times are well resolved, many issues pertaining to the fit reconstruction and particular the relation between kinematics and lithosphere dynamics during pre-breakup remain unclear in currently published plate models. We have compiled and assimilated data from these intraplated rifts and constructed a revised plate kinematic model for the pre-breakup evolution of the South Atlantic. Based on structural restoration of the conjugate South Atlantic margins and intracontinental rift basins in Africa and South America, we achieve a tight fit reconstruction which eliminates the need for previously inferred large intracontinental shear zones, in particular in Patagonian South America. By quantitatively accounting for crustal deformation in the Central and West African rift zone, we have been able to indirectly construct the kinematic history of the pre-breakup evolution of the conjugate West African-Brazilian margins. Our model suggests a causal link between changes in extension direction and velocity during continental extension and the generation of marginal structures such as the enigmatic Pre-salt sag basin and the São Paulo High. We model an initial E–W directed extension between South America and Africa (fixed in present-day position at very low extensional velocities until Upper Hauterivian times (≈126 Ma when rift activity along in the equatorial Atlantic domain started to increase significantly. During this initial ≈17 Myr-long stretching episode the Pre-salt basin width on the conjugate Brazilian and West African margins is generated. An intermediate stage between 126.57 Ma and Base Aptian is characterised by strain localisation, rapid lithospheric weakening in the

  20. Activity prediction of substrates in NADH-dependent carbonyl reductase by docking requires catalytic constraints and charge parameterization of catalytic zinc environment.

    Science.gov (United States)

    Dhoke, Gaurao V; Loderer, Christoph; Davari, Mehdi D; Ansorge-Schumacher, Marion; Schwaneberg, Ulrich; Bocola, Marco

    2015-11-01

    Molecular docking of substrates is more challenging compared to inhibitors as the reaction mechanism has to be considered. This becomes more pronounced for zinc-dependent enzymes since the coordination state of the catalytic zinc ion is of greater importance. In order to develop a predictive substrate docking protocol, we have performed molecular docking studies of diketone substrates using the catalytic state of carbonyl reductase 2 from Candida parapsilosis (CPCR2). Different docking protocols using two docking methods (AutoDock Vina and AutoDock4.2) with two different sets of atomic charges (AM1-BCC and HF-RESP) for catalytic zinc environment and substrates as well as two sets of vdW parameters for zinc ion were examined. We have selected the catalytic binding pose of each substrate by applying mechanism based distance criteria. To compare the performance of the docking protocols, the correlation plots for the binding energies of these catalytic poses were obtained against experimental Vmax values of the 11 diketone substrates for CPCR2. The best correlation of 0.73 was achieved with AutoDock4.2 while treating catalytic zinc ion in optimized non-bonded (NBopt) state with +1.01 charge on the zinc ion, compared to 0.36 in non-bonded (+2.00 charge on the zinc ion) state. These results indicate the importance of catalytic constraints and charge parameterization of catalytic zinc environment for the prediction of substrate activity in zinc-dependent enzymes by molecular docking. The developed predictive docking protocol described here is in principle generally applicable for the efficient in silico substrate spectra characterization of zinc-dependent ADH.

  1. Multibody motion in implicitly constrained director format with links via explicit constraints

    DEFF Research Database (Denmark)

    Nielsen, Martin Bjerre; Krenk, Steen

    2013-01-01

    A conservative time integration algorithm is developed for constrained mechanical systems of kinematically linked rigid bodies based on convected base vectors. The base vectors are represented in terms of their absolute coordinates, hence the formulation makes use of three translation components......, plus nine base vector components for each rigid body. Both internal and external constraints are considered. Internal constraints are used to enforce orthonormality of the three base vectors by constraining the equivalent Green strain components, while the external constraints are associated...... with the presence of kinematic joints for linking bodies together. The equations of motion are derived from Hamilton’s equations with an augmented Hamiltonian in which internal and external constraints initially are included via Lagrange multipliers. Subsequently the Lagrange multipliers associated with internal...

  2. Kinematics of the free throw in basketball

    Science.gov (United States)

    Tan, A.; Miller, G.

    1981-06-01

    The kinematics of the two basic styles of free throw in basketball are discussed. It is shown that from a purely kinematic and trajectory point of view, the overhand push shot is preferable to the underhand loop shot. The advantages of the underhand shot lie in the actual execution of the shot.

  3. Knee Kinematics Estimation Using Multi-Body Optimisation Embedding a Knee Joint Stiffness Matrix: A Feasibility Study.

    Science.gov (United States)

    Richard, Vincent; Lamberto, Giuliano; Lu, Tung-Wu; Cappozzo, Aurelio; Dumas, Raphaël

    2016-01-01

    The use of multi-body optimisation (MBO) to estimate joint kinematics from stereophotogrammetric data while compensating for soft tissue artefact is still open to debate. Presently used joint models embedded in MBO, such as mechanical linkages, constitute a considerable simplification of joint function, preventing a detailed understanding of it. The present study proposes a knee joint model where femur and tibia are represented as rigid bodies connected through an elastic element the behaviour of which is described by a single stiffness matrix. The deformation energy, computed from the stiffness matrix and joint angles and displacements, is minimised within the MBO. Implemented as a "soft" constraint using a penalty-based method, this elastic joint description challenges the strictness of "hard" constraints. In this study, estimates of knee kinematics obtained using MBO embedding four different knee joint models (i.e., no constraints, spherical joint, parallel mechanism, and elastic joint) were compared against reference kinematics measured using bi-planar fluoroscopy on two healthy subjects ascending stairs. Bland-Altman analysis and sensitivity analysis investigating the influence of variations in the stiffness matrix terms on the estimated kinematics substantiate the conclusions. The difference between the reference knee joint angles and displacements and the corresponding estimates obtained using MBO embedding the stiffness matrix showed an average bias and standard deviation for kinematics of 0.9±3.2° and 1.6±2.3 mm. These values were lower than when no joint constraints (1.1±3.8°, 2.4±4.1 mm) or a parallel mechanism (7.7±3.6°, 1.6±1.7 mm) were used and were comparable to the values obtained with a spherical joint (1.0±3.2°, 1.3±1.9 mm). The study demonstrated the feasibility of substituting an elastic joint for more classic joint constraints in MBO.

  4. Knee Kinematics Estimation Using Multi-Body Optimisation Embedding a Knee Joint Stiffness Matrix: A Feasibility Study.

    Directory of Open Access Journals (Sweden)

    Vincent Richard

    Full Text Available The use of multi-body optimisation (MBO to estimate joint kinematics from stereophotogrammetric data while compensating for soft tissue artefact is still open to debate. Presently used joint models embedded in MBO, such as mechanical linkages, constitute a considerable simplification of joint function, preventing a detailed understanding of it. The present study proposes a knee joint model where femur and tibia are represented as rigid bodies connected through an elastic element the behaviour of which is described by a single stiffness matrix. The deformation energy, computed from the stiffness matrix and joint angles and displacements, is minimised within the MBO. Implemented as a "soft" constraint using a penalty-based method, this elastic joint description challenges the strictness of "hard" constraints. In this study, estimates of knee kinematics obtained using MBO embedding four different knee joint models (i.e., no constraints, spherical joint, parallel mechanism, and elastic joint were compared against reference kinematics measured using bi-planar fluoroscopy on two healthy subjects ascending stairs. Bland-Altman analysis and sensitivity analysis investigating the influence of variations in the stiffness matrix terms on the estimated kinematics substantiate the conclusions. The difference between the reference knee joint angles and displacements and the corresponding estimates obtained using MBO embedding the stiffness matrix showed an average bias and standard deviation for kinematics of 0.9±3.2° and 1.6±2.3 mm. These values were lower than when no joint constraints (1.1±3.8°, 2.4±4.1 mm or a parallel mechanism (7.7±3.6°, 1.6±1.7 mm were used and were comparable to the values obtained with a spherical joint (1.0±3.2°, 1.3±1.9 mm. The study demonstrated the feasibility of substituting an elastic joint for more classic joint constraints in MBO.

  5. Kinematics of planet-host stars and their relation with dynamical streams in the solar neighbourhood

    CERN Document Server

    Ecuvillon, A; Pont, F; Santos, N C; Mayor, M

    2006-01-01

    We present a detailed study on the kinematics of metal-rich stars with and without planets, and their relation with the Hyades, Sirius and Hercules dynamical streams in the solar neighbourhood. Accurate kinematics have been derived for all the stars belonging to the CORALIE planet search survey. We used precise radial velocity measurements and CCF parameters from the CORALIE database, and parallaxes, photometry and proper motions from the HIPPARCOS and Tycho-2 catalogues. The location of stars with planets in the thin or thick discs has been analysed using both kinematic and chemical constraints. We compare the kinematic behaviour of known planet-host stars to the remaining targets belonging to the volume-limited sample, in particular to its metal-rich population. The high average metallicity of the Hyades stream is confirmed. The planet-host targets show a kinematic behaviour similar to that of the metal-rich comparison subsample, rather than to that of the comparison sample as a whole, thus supporting a pri...

  6. The kinematics modeling based on Spinor theory for CT-guided hybrid robot

    Institute of Scientific and Technical Information of China (English)

    Tang Can; Liu Da; Wang Tianmiao; Yun Chao

    2009-01-01

    This paper focused on a simplified method for solving the hybrid robot kinematics in CT-guided (computerized tomography, CT) surgery. By position constraint introduced, the hybrid robot can be transformed as a redundant serial 7-DOF robot. The forward displacement calculation was developed based on the product-of-exponential formula (POE). Because of the kinematics complexity of the hybrid and redundant robot, the combination technique of Ulrich two-step iteration method and paul variables detachment method (UTI-PVD) was introduced to fulfill the inverse kinematics of redundant robot, the novelty of which lay in the flexibility of various robots structures and in high calculation efficiency for real-time control. The process of solving the inverse displacement was analyzed. The UTI-PVD method can be applicable to kinematics of many robots, especially for redundant robots with more than 6DOF. The kinematics simulation was provided, and robot dexterity analysis was presented. The results indicated that the hybrid robot could implement the minimally invasive CT-guided surgery.

  7. Off-shell Color-Kinematics Duality

    CERN Document Server

    Mastrolia, Pierpaolo; Schubert, Ulrich; Bobadilla, William J Torres

    2015-01-01

    We elaborate on the color-kinematics duality for off-shell diagrams in gauge theories coupled to matter, by investigating the scattering process $gg\\to ss, q\\bar q, gg$, and show that the Jacobi relations for the kinematic numerators of off-shell diagrams, built with Feynman rules in axial gauge, reduces to a color-kinematics violating term due to the contributions of sub-graphs only. Such anomaly vanishes when the four particles connected by the Jacobi relation are on their mass shell with vanishing squared momenta, being either external or cut particles, where the validity of the color-kinematics duality is recovered. We discuss the role of this off-shell decomposition in the direct construction of higher-multiplicity numerators satisfying color-kinematics identity, providing an explicit example for the QCD process $gg\\to q\\bar{q}g$.

  8. Theory of Constraints (TOC)

    DEFF Research Database (Denmark)

    Michelsen, Aage U.

    2004-01-01

    Tankegangen bag Theory of Constraints samt planlægningsprincippet Drum-Buffer-Rope. Endvidere skitse af The Thinking Process.......Tankegangen bag Theory of Constraints samt planlægningsprincippet Drum-Buffer-Rope. Endvidere skitse af The Thinking Process....

  9. Temporal Concurrent Constraint Programming

    DEFF Research Database (Denmark)

    Nielsen, Mogens; Palamidessi, Catuscia; Valencia, Frank Dan

    2002-01-01

    The ntcc calculus is a model of non-deterministic temporal concurrent constraint programming. In this paper we study behavioral notions for this calculus. In the underlying computational model, concurrent constraint processes are executed in discrete time intervals. The behavioral notions studied...

  10. Evaluating Distributed Timing Constraints

    DEFF Research Database (Denmark)

    Kristensen, C.H.; Drejer, N.

    1994-01-01

    In this paper we describe a solution to the problem of implementing time-optimal evaluation of timing constraints in distributed real-time systems.......In this paper we describe a solution to the problem of implementing time-optimal evaluation of timing constraints in distributed real-time systems....

  11. Probing RNA Native Conformational Ensembles with Structural Constraints.

    Science.gov (United States)

    Fonseca, Rasmus; van den Bedem, Henry; Bernauer, Julie

    2016-05-01

    Noncoding ribonucleic acids (RNA) play a critical role in a wide variety of cellular processes, ranging from regulating gene expression to post-translational modification and protein synthesis. Their activity is modulated by highly dynamic exchanges between three-dimensional conformational substates, which are difficult to characterize experimentally and computationally. Here, we present an innovative, entirely kinematic computational procedure to efficiently explore the native ensemble of RNA molecules. Our procedure projects degrees of freedom onto a subspace of conformation space defined by distance constraints in the tertiary structure. The dimensionality reduction enables efficient exploration of conformational space. We show that the conformational distributions obtained with our method broadly sample the conformational landscape observed in NMR experiments. Compared to normal mode analysis-based exploration, our procedure diffuses faster through the experimental ensemble while also accessing conformational substates to greater precision. Our results suggest that conformational sampling with a highly reduced but fully atomistic representation of noncoding RNA expresses key features of their dynamic nature.

  12. Functional constraints on SoxE proteins in neural crest development: The importance of differential expression for evolution of protein activity.

    Science.gov (United States)

    Lee, Eric M; Yuan, Tian; Ballim, Reyna D; Nguyen, Kristy; Kelsh, Robert N; Medeiros, Daniel M; McCauley, David W

    2016-10-01

    Vertebrate SoxE genes (Sox8, 9, and 10) are key regulators of neural crest cell (NCC) development. These genes arose by duplication from a single SoxE gene in the vertebrate ancestor. Although SoxE paralogs are coexpressed early in NCC development, later, Sox9 is restricted to skeletogenic lineages in the head, and Sox10 to non-skeletogenic NCC in the trunk and head. When this subfunctionalization evolved and its possible role in the evolution of the neural crest are unknown. Sea lampreys are basal vertebrates that also possess three SoxE genes, while only a single SoxE is present in the cephalochordate amphioxus. In order to address the functional divergence of SoxE genes, and to determine if differences in their biochemical functions may be linked to changes in neural crest developmental potential, we examined the ability of lamprey and amphioxus SoxE genes to regulate differentiation of NCC derivatives in zebrafish colourless (cls) mutants lacking expression of sox10. Our findings suggest that the proto-vertebrate SoxE gene possessed both melanogenic and neurogenic capabilities prior to SoxE gene duplication. Following the agnathan-gnathostome split, lamprey SoxE1 and SoxE3 largely lost their melanogenic and/or enteric neurogenic properties, while gnathostome SoxE paralogs have retained functional conservation. We posit that this difference in protein subfunctionalization is a direct consequence of the independent regulation of SoxE paralog expression between the two lineages. Specifically, we propose that the overlapping expression of gnathostome SoxE paralogs in early neural crest largely constrained the function of gnathostome SoxE proteins. In contrast, the largely non-overlapping expression of lamprey SoxE paralogs allowed them to specialize with regard to their DNA-binding and/or protein interaction properties. Restriction of developmental potential among cranial and trunk neural crest in lampreys may be related to constraints on SoxE activity among

  13. Decentralized Constraint Satisfaction

    CERN Document Server

    Duffy, K R; Leith, D J

    2011-01-01

    Constraint satisfaction problems (CSPs) lie at the heart of many modern industrial and commercial tasks. An important new collection of CSPs has recently been emerging that differ from classical problems in that they impose constraints on the class of algorithms that can be used to solve them. In computer network applications, these constraints arise as the variables within the CSP are located at physically distinct devices that cannot communicate. At each instant, every variable only knows if all its constraints are met or at least one is not. Consequently, the CSP's solution must be found using a decentralized approach. Existing algorithms for solving CSPs are either centralized or distributed, both of which violate these algorithmic constraints. In this article we present the first algorithm for solving CSPs that fulfills these new requirements. It is fully decentralized, making no use of a centralized controller or message-passing between variables. We prove that this algorithm converges with probability ...

  14. Constraints in Quantum Geometrodynamics

    CERN Document Server

    Gentle, A P; Kheyfets, A I; Miller, W A; Gentle, Adrian P.; George, Nathan D.; Kheyfets, Arkady; Miller, Warner A.

    2003-01-01

    We compare different treatments of the constraints in canonical quantum gravity. The standard approach on the superspace of 3-geometries treats the constraints as the sole carriers of the dynamic content of the theory, thus rendering the traditional dynamic equations obsolete. Quantization of the constraints in both the Dirac and ADM square root Hamiltonian approach lead to the well known problems of the description of time evolution. These problems of time are both of interpretational and technical nature. In contrast, the so-called geometrodynamic quantization procedure on the superspace of the true dynamic variables separates the issue of quantization from enforcing the constraints. The resulting theory takes into account the states that are off shell with respect to the constraints, and thus avoids the problems of time. Here, we develop, for the first time, the geometrodynamic quantization formalism in a general setting and show that it retains all essential features previously illustrated in the context ...

  15. Effects of modified constraint-induced movement therapy and functional bimanual training on upper extremity function and daily activities in a patient with incomplete spinal cord injury: a case study.

    Science.gov (United States)

    Kim, Yeon-Ju; Kim, Jin-Kyung; Park, So-Yeon

    2015-12-01

    [Purpose] In this study, we examined effects of modified constraint-induced movement therapy (m-CIMT) and functional bimanual training, when applied to a patient with incomplete spinal cord injury, on upper extremity function and daily activities. [Subject and Methods] One patient, diagnosed with C4 incomplete spinal cord injury, underwent physical therapy with constraint-induced movement therapy for 3 hours and task-oriented bimanual training for 1 hour, per day. This combined 4-hour session was performed five times a week, for 3 weeks, totaling 15 sessions. Upper extremity function was measured using the Manual Function Test (MFT) and Box & Block Test (BBT). Additionally, Spinal Cord Independence Measure Version III (SCIM-III) and Short Form 36 Health Survey (SF-36) were used to assess functional outcomes. [Results] Mobility of the hand and overall function of upper extremities were enhanced following intervention. Moreover, the subject's quality of life and ability to carry out daily activities also improved. [Conclusion] Modified constraint-induced movement therapy and bimanual training was effective in enhancing upper extremity function and performance of daily routines in a patient with incomplete spinal cord injury. Further studies, recruiting multiple subjects, should focus on m-CIMT using diverse methods, performed during the course of daily activities.

  16. Intervertebral anticollision constraints improve out-of-plane translation accuracy of a single-plane fluoroscopy-to-CT registration method for measuring spinal motion

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Cheng-Chung; Tsai, Tsung-Yuan; Hsu, Shih-Jung [Institute of Biomedical Engineering, National Taiwan University, Taiwan 10051 (China); Lu, Tung-Wu [Institute of Biomedical Engineering, National Taiwan University, Taiwan 10051, Republic of China and Department of Orthopaedic Surgery, School of Medicine, National Taiwan University, Taiwan 10617 (China); Shih, Ting-Fang [Department of Medical Imaging, National Taiwan University, Taiwan 10051 (China); Wang, Ting-Ming [Department of Orthopaedic Surgery, National Taiwan University Hospital, Taiwan 10051 (China)

    2013-03-15

    Purpose: The study aimed to propose a new single-plane fluoroscopy-to-CT registration method integrated with intervertebral anticollision constraints for measuring three-dimensional (3D) intervertebral kinematics of the spine; and to evaluate the performance of the method without anticollision and with three variations of the anticollision constraints via an in vitro experiment. Methods: The proposed fluoroscopy-to-CT registration approach, called the weighted edge-matching with anticollision (WEMAC) method, was based on the integration of geometrical anticollision constraints for adjacent vertebrae and the weighted edge-matching score (WEMS) method that matched the digitally reconstructed radiographs of the CT models of the vertebrae and the measured single-plane fluoroscopy images. Three variations of the anticollision constraints, namely, T-DOF, R-DOF, and A-DOF methods, were proposed. An in vitro experiment using four porcine cervical spines in different postures was performed to evaluate the performance of the WEMS and the WEMAC methods. Results: The WEMS method gave high precision and small bias in all components for both vertebral pose and intervertebral pose measurements, except for relatively large errors for the out-of-plane translation component. The WEMAC method successfully reduced the out-of-plane translation errors for intervertebral kinematic measurements while keeping the measurement accuracies for the other five degrees of freedom (DOF) more or less unaltered. The means (standard deviations) of the out-of-plane translational errors were less than -0.5 (0.6) and -0.3 (0.8) mm for the T-DOF method and the R-DOF method, respectively. Conclusions: The proposed single-plane fluoroscopy-to-CT registration method reduced the out-of-plane translation errors for intervertebral kinematic measurements while keeping the measurement accuracies for the other five DOF more or less unaltered. With the submillimeter and subdegree accuracy, the WEMAC method was

  17. Torque exerted on the side of crustal blocks controls the kinematics of Ethiopian Rift

    Science.gov (United States)

    Muluneh, Ameha A.; Kidane, Tesfaye; Cuffaro, Marco; Doglioni, Carlo

    2016-04-01

    Plate tectonic stress at active plate boundary can arises from 1) a torque applied on the side of lithospheric blocks and 2) a torque at the base of the lithosphere due to the flow of the underlying mantle. In this paper we use a simple force balance analysis to compare side and basal shear stresses and their contribution in driving kinematics and deformation in the Ethiopian Rift (ER), in the northern part of the East African Rift System (EARS). Assuming the constraints of the ER given by the dimension of the lithospheric blocks, the strain rate, the viscosity of the low velocity zone (LVZ) and the depth of the brittle-ductile transition zone, the lateral torque is several orders of magnitude higher than the basal torque. The minor contribution of basal torque might be due to low viscosity in the LVZ. Both Africa and Somalia plates are moving to the "west" relative to the mantle and there are not slabs that can justify this pull and consequent motion. Therefore, we invoke that westerly oriented tidal torque on Africa and Somalia plates in providing the necessary side torque in the region. This plate motion predicts significant sinistral transtension along the ER and rift parallel strike-slip faulting similar to the estimated angular velocity vector for tectonic blocks and GPS observations. Vertical axis block rotations are observed in areas where the lithospheric mantle is removed and strain is widely distributed.

  18. Constraint-based reachability

    Directory of Open Access Journals (Sweden)

    Arnaud Gotlieb

    2013-02-01

    Full Text Available Iterative imperative programs can be considered as infinite-state systems computing over possibly unbounded domains. Studying reachability in these systems is challenging as it requires to deal with an infinite number of states with standard backward or forward exploration strategies. An approach that we call Constraint-based reachability, is proposed to address reachability problems by exploring program states using a constraint model of the whole program. The keypoint of the approach is to interpret imperative constructions such as conditionals, loops, array and memory manipulations with the fundamental notion of constraint over a computational domain. By combining constraint filtering and abstraction techniques, Constraint-based reachability is able to solve reachability problems which are usually outside the scope of backward or forward exploration strategies. This paper proposes an interpretation of classical filtering consistencies used in Constraint Programming as abstract domain computations, and shows how this approach can be used to produce a constraint solver that efficiently generates solutions for reachability problems that are unsolvable by other approaches.

  19. Communication with Disturbance Constraints

    CERN Document Server

    Bandemer, Bernd

    2011-01-01

    The problem of communication with disturbance constraints is introduced. The rate-disturbance region is established for the single constraint case. The optimal encoding scheme turns out to be the same as the Han-Kobayashi scheme for the two user-pair interference channel. For communication with two disturbance constraints, a coding scheme and a corresponding inner bound for the deterministic case are presented. The results suggest a natural way to obtain a new inner bound on the capacity region of the interference channel with more than two user pairs.

  20. Inverse Kinematics With Closed Form Solution For Denso Robot Manipulator

    Directory of Open Access Journals (Sweden)

    Ikhsan Eka Prasetia

    2015-03-01

    Full Text Available In this paper, the forward kinematics and inverse kinematics used on the Denso robot manipulator which has a 6-DOF. The forward kinematics will result in the desired position by end-effector, while inverse kinematics produce angel on each joint. Inverse kinematics problem are very difficult, therefor to obtain the solution of inverse kinematics using closed form solution with geometry approach. The simulation result obtained from forward kinematics and inverse kinematics is determining desired position by Denso robot manipulator. Forward kinematics produce the desired position by the end-effector. Inverse kinematics produce joint angle, where the inverse kinematics produce eight conditions obtained from closed form solution with geometry approach to reach the desired position by the end-effector.

  1. Anisotropic superconductivity driven by kinematic interaction

    Science.gov (United States)

    Ivanov, V. A.

    2000-11-01

    We have analysed the effect of kinematic pairing on the symmetry of superconducting order parameter for a square lattice in the frame of the strongly correlated Hubbard model. It is argued that in the first perturbation order the kinematic interaction renormalizes the Hubbard-I dispersions and provides at low doping the mixed singlet (s + s*)-wave superconductivity, giving way at higher doping to the triplet p-wave superconductivity. The obtained phase diagram depends only on the hopping integral parameter. The influence of the Coulomb repulsion on the kinematic superconducting pairing has been estimated. The (s + s*)-wave gap and the thermodynamic critical magnetic field have been derived.

  2. Optimization under Nonlinear Constraints

    OpenAIRE

    1982-01-01

    In this paper a timesaving method is proposed for maximizing likelihood functions when the parameter space is subject to nonlinear constraints, expressible as second order polynomials. The suggested approach is especially attractive when dealing with systems with many parameters.

  3. Astrophysical Constraints on Planck Scale Dissipative Phenomena

    Science.gov (United States)

    Liberati, Stefano; Maccione, Luca

    2014-04-01

    The emergence of a classical spacetime from any quantum gravity model is still a subtle and only partially understood issue. If indeed spacetime is arising as some sort of large scale condensate of more fundamental objects, then it is natural to expect that matter, being a collective excitation of the spacetime constituents, will present modified kinematics at sufficiently high energies. We consider here the phenomenology of the dissipative effects necessarily arising in such a picture. Adopting dissipative hydrodynamics as a general framework for the description of the energy exchange between collective excitations and the spacetime fundamental degrees of freedom, we discuss how rates of energy loss for elementary particles can be derived from dispersion relations and used to provide strong constraints on the base of current astrophysical observations of high-energy particles.

  4. Constraint-Referenced Analytics of Algebra Learning

    Science.gov (United States)

    Sutherland, Scot M.; White, Tobin F.

    2016-01-01

    The development of the constraint-referenced analytics tool for monitoring algebra learning activities presented here came from the desire to firstly, take a more quantitative look at student responses in collaborative algebra activities, and secondly, to situate those activities in a more traditional introductory algebra setting focusing on…

  5. Edge-driven microplate kinematics

    Science.gov (United States)

    Schouten, Hans; Klitgord, Kim D.; Gallo, David G.

    1993-01-01

    It is known from plate tectonic reconstructions that oceanic microplates undergo rapid rotation about a vertical axis and that the instantaneous rotation axes describing the microplate's motion relative to the bounding major plates are frequently located close to its margins with those plates, close to the tips of propagating rifts. We propose a class of edge-driven block models to illustrate how slip across the microplate margins, block rotation, and propagation of rifting may be related to the relative motion of the plates on either side. An important feature of these edge-driven models is that the instantaneous rotation axes are always located on the margins between block and two bounding plates. According to those models the pseudofaults or traces of disrupted seafloor resulting from the propagation of rifting between microplate and major plates may be used independently to approximately trace the continuous kinematic evolution of the microplate back in time. Pseudofault geometries and matching rotations of the Easter microplate show that for most of its 5 m.y. history, block rotation could be driven by the drag of the Nazca and Pacific plates on the microplate's edges rather than by a shear flow of mantle underneath.

  6. Kinematics of the Hercules Supercluster

    CERN Document Server

    Barmby, P; Barmby, Pauline; Huchra, John P.

    1997-01-01

    The Hercules Supercluster consists of the Abell clusters 2147, 2151, and 2152. Previous studies of the kinematics have been confounded by the difficulty of correctly assigning galaxies to the individual clusters, which are not well-separated. Our study has a total of 468 available velocities for galaxies in the region, 175 of them new. 414 galaxies are in the supercluster, about three times the number used in the previous supercluster study. We verify the existence of the three individual clusters and compute their individual dynamical parameters. We investigate several techniques for assigning galaxy membership to clusters in this crowded field. We use the KMM mixture-modeling algorithm to separate the galaxies into clusters; we find that A2152 has a higher mean velocity than previous studies have reported. A2147 and A2152 also have lower velocity dispersions: 821(+68)(-55) and 715(+81)(-61) km/s. The assignment of galaxies to either A2152 or A2147 requires velocity and position information. We study the kin...

  7. Impact of uncertain reference-frame motions in plate kinematic reconstructions: A theoretical appraisal

    Science.gov (United States)

    Iaffaldano, Giampiero; Stein, Seth

    2017-01-01

    Geoscientists infer past plate motions, which serve as fundamental constraints for a range of studies, from observations of magnetic isochrons as well as hotspots tracks on the ocean floor and, for stages older than the Cretaceous, from paleomagnetic data. These observations effectively represent time-integrals of past plate motions but, because they are made at present, yield plate kinematics naturally tied to a present-day reference-frame, which may be another plate or a hotspots system. These kinematics are therefore different than those occurred at the time when the rocks acquired their magnetisation or when hotspot-related marine volcanism took place, and are normally corrected for the reference-frame absolute motion (RFAM) that occurred since then. The impact of true-polar-wander events on paleomagnetic data and the challenge of inferring hotspot drifts result in RFAMs being less resolved - in a temporal sense - and prone to noise. This limitation is commonly perceived to hamper the correction of plate kinematic reconstructions for RFAMs, but the extent to which this may be the case has not been explored. Here we assess the impact of uncertain RFAMs on kinematic reconstructions using synthetic models of plate motions over 100 million years. We use randomly-drawn models for the kinematics of two plates separated by a spreading ridge to generate a synthetic magnetisation pattern of the ocean floor. The kinematics we infer from such a pattern are outputs that we correct for synthetic RFAMs using two equivalent methods (a classical one as well as another that we propose and test here) and then compare to the 'true' motions input. We assess the misfits between true and inferred kinematics by exploring a statistically-significant number of models where we systematically downgrade the temporal resolution of RFAM synthetic data and add noise to them. We show that even poorly-resolved, noisy RFAMs are sufficient to retrieve reliable plate kinematic reconstructions

  8. Estimating total knee replacement joint load ratios from kinematics.

    Science.gov (United States)

    Fitzpatrick, Clare K; Rullkoetter, Paul J

    2014-09-22

    Accurate prediction of loads acting at the joint in total knee replacement (TKR) patients is key to developing experimental or computational simulations which evaluate implant designs under physiological loading conditions. In vivo joint loads have been measured for a small number of telemetric TKR patients, but in order to assess device performance across the entire patient population, a larger patient cohort is necessary. This study investigates the accuracy of predicting joint loads from joint kinematics. Specifically, the objective of the study was to assess the accuracy of internal-external (I-E) and anterior-posterior (A-P) joint load predictions from I-E and A-P motions under a given compressive load, and to evaluate the repeatability of joint load ratios (I-E torque to compressive force (I-E:C), and A-P force to compressive force (A-P:C)) for a range of compressive loading profiles. A tibiofemoral finite element model was developed and used to simulate deep knee bend, chair-rise and step-up activities for five patients. Root-mean-square (RMS) differences in I-E:C and A-P:C load ratios between telemetric measurements and model predictions were less than 1.10e-3 Nm/N and 0.035 N/N for all activities. I-E:C and A-P:C load ratios were consistently reproduced regardless of the compressive force profile applied (RMS differences less than 0.53e-3 Nm/N and 0.010 N/N, respectively). When error in kinematic measurement was introduced to the model, joint load predictions were forgiving to kinematic measurement error when conformity between femoral and tibial components was low. The prevalence of kinematic data, in conjunction with the analysis presented here, facilitates determining the scope of A-P and I-E joint loading ratios experienced by the TKR population.

  9. Dynamic Control of Kinematically Redundant Robotic Manipulators

    Directory of Open Access Journals (Sweden)

    Erling Lunde

    1987-07-01

    Full Text Available Several methods for task space control of kinematically redundant manipulators have been proposed in the literature. Most of these methods are based on a kinematic analysis of the manipulator. In this paper we propose a control algorithm in which we are especially concerned with the manipulator dynamics. The algorithm is particularly well suited for the class of redundant manipulators consisting of a relatively small manipulator mounted on a larger positioning part.

  10. Chiral quark model with relativistic kinematics

    CERN Document Server

    Garcilazo, H

    2003-01-01

    The non-strange baryon spectrum is studied within a three-body model that incorporates relativistic kinematics. We found that the combined effect of relativistic kinematics together with the pion exchange between quarks is able to reverse the order of the first positive- and negative-parity nucleon excited states as observed experimentally. Including the chiral partner of the pion (the $\\sigma$ meson) leads to an overall good description of the spectrum.

  11. KINEMATIC ANALYSIS OF MODULAR, TRUSS-BASED MANIPULATOR UNITS

    Energy Technology Data Exchange (ETDEWEB)

    Salerno, R. J.

    1994-06-01

    Decontamination and Dismantling (D&D) activities within the U.S. Department of Energy (DOE) require a long reach manipulator with a large load capacity. Variable Geometry Trusses (VGTs) are a unique class of mechanical structures which allow the advantages of truss structures for large scale applications to be applied to large robotic manipulators. Individual VGT units may be assembled to create a modular, long-reach, truss-type manipulator. Each module of such a manipulator system is either a static truss section or one of several possible VGT geometries. While many potential applications exist for this technology, the present work is largely motivated by the need for generic robotic systems for remote manipulation. A manipulator system based on VGT modules provides several advantages. The reconfigurable nature of the manipulator system allows it to be adapted on site to unforeseen conditions. The kinematic redundancy of the manipulator enables it to work effectively even in a highly obstructed workspace. The parallel structure of the truss modules enables the manipulator to be withdrawn in the event of a structural failure. Finally, the open framework of the modules provides a clear, protected passageway for control and power cabling, waste conveyance, or other services required at the end effector. As is implied in a truss structure, all primary members of a VGT are ideally loaded in pure tension or compression. This results in an extremely stiff and strong manipulator system with minimal overall weight. Careful design of the joints of a VGT is very important to the overall stiffness and accuracy of the structure, as several links (as many as six) are joined together at each joint. The greatest disadvantage to this approach to manipulator design has traditionally been that the kinematics of VGT structures are complex and poorly understood. This report specifically addresses the kinematics of several possible geometries for the individual VGT units. Equations and

  12. Implementation of Complex Projects Using Constraint Programming

    Directory of Open Access Journals (Sweden)

    Miodrag Strak

    2012-09-01

    Full Text Available During the implementation of the complex projects, all planned activities and resources must be taken into account. In general, it is necessary to assign the resources to the activities, but to also avoid simultaneous engagement of resources for multiple activities. In order to solve these problems, various techniques and methods are used. Mathematic and integer programming, genetic algorithms, simulated annealing, or taboo search are just some of the techniques used for solving this problem. Constraint programming comes from artificial intelligence i.e. papers from this area that occurred in 1960s and 1970s. Constraints exist in every segment of human environment. They represent a natural medium for expressing relations that exist in the physical world. Fulfilment of constraints is used in many different areas. Problems such as scheduling, allocations etc. are typical examples of constraints problems, where the basic concept of constraint programming can be applied. This paper considered implementation of the Bor Regional Development Project. Development of constraint programming was followed by the development of appropriate tools. B-Prolog was used in this paper. Many systems, including B-Prolog, enable interface with classic object-oriented languages, such as C++ or Java. One of the greatest advantages is the possibility of simple modelling, even for beginners in planning and implementation of the project.

  13. Geometry and kinematics of the Xianshuihe fault belt in southwestern Sichuan, eastern Tibetan Plateau: Constraints from magnetic fabrics%青藏高原东缘鲜水河断裂带磁组构特征及构造意义

    Institute of Scientific and Technical Information of China (English)

    陈应涛; 张国伟; 鲁如魁; 谢晋强; 郭泱泱

    2013-01-01

    为了探究鲜水河断裂带的几何学、运动学特征,在野外构造、显微构造分析基础上,研究了鲜水河断裂带296块构造岩定向样品的磁组构特征和热磁特征,结果显示样品的平均磁化率km值总体较小,属微弱磁性到弱磁性;热磁实验及其显微构造表明顺磁性的页硅酸盐(如黑云母)等矿物对糜棱岩类样品磁化率贡献较大;磁化率各向异性度PJ总体较大,表明鲜水河断裂带构造变形强烈;磁化率椭球体形状参数T总体大于0,扁率E总体在1附近分布,说明鲜水河断裂带磁化率椭球体以扁圆形为主,整体上磁面理较磁线理发育,进一步显示出鲜水河断裂带构造变形样式以剪切、压扁为主,伴有拉伸的构造变形,同时也反映出鲜水河断裂带多次变形的综合特征;最小磁化率主轴Kmin方位表明鲜水河断裂带北段和南段分别受近EW向和NE-SW向主压应力控制;同时Kmin方位及其倾伏角特征显示鲜水河断裂带总体以左行走滑剪切为主,北段两侧块体在鲜水河断裂带两次不同的构造活动时期,各自有一定的相对抬升,但抬升幅度均不大;南段则是SW块体相对NE块体抬升,抬升幅度较大;整个断裂带特征显示出鲜水河断裂带在向南发展逐渐转化为挤压构造,这可能与青藏高原物质的向东逃逸受阻以及鲜水河断裂带与龙门山断裂带在此交接的地质背景不无关系.%In order to probe into the geometry and kinematics of the Xianshuihe fault belt, this paper carried out a structural deformation characteristics research to the Xianshuihe fault belt through the anisotropy of magnetic susceptibility ( AMS) and thermomagnetic analyses of 296 oriented samples on the basis of the field structural, and microstructural analyses. Average susceptibility ( km ) values of the collected samples are generally small so that they are slightly weak magnetic to weak magnetic. Thermomagnetic curves and

  14. Kinematics of AGN and Quasar Jets

    CERN Document Server

    Kellermann, K I; Homan, D C; Kovalev, Y Y; Kadler, M; Cohen, M C

    2008-01-01

    The major multi-epoch VLBA programs are described and discussed in terms of relativistic beaming models. Broadly speaking the observed kinematics are consistent with models having a parent population which is only mildly relativistic but with Lorentz factors extending up to about 30. While the collimation and acceleration appears to mainly occur close to the central engine, there is evidence of accelerations up to 1 kpc downstream. Generally the motion appears to be linear, but in some sources the motion follows a curved trajectory. In other sources, successive features appear to be ejected in different directions possibly the result of a precessing nozzle. The launch of GLAST in 2008 will offer new opportunities to study the relation between radio and gamma-ray activity, and possibly to locate the source of the gamma-ray emission. VSOP-2 will give enhanced resolution and will facilitate the study of the two-dimensional structure of relativistic jets, while RadioAstron will provide unprecedented resolution to...

  15. Kinematics of the South Atlantic rift

    CERN Document Server

    Heine, Christian; Müller, R Dietmar

    2013-01-01

    The South Atlantic rift basin evolved as branch of a large Jurassic-Cretaceous intraplate rift zone between the African and South American plates during the final breakup of western Gondwana. By quantitatively accounting for crustal deformation in the Central and West African rift zone, we indirectly construct the kinematic history of the pre-breakup evolution of the conjugate West African-Brazilian margins. Our model suggests a causal link between changes in extension direction and velocity during continental extension and the generation of marginal structures such as the enigmatic Pre-salt sag basin and the S\\~ao Paulo High. We model an initial E-W directed extension between South America and Africa (fixed in present-day position) at very low extensional velocities until Upper Hauterivian times ($\\approx$126 Ma) when rift activity along in the equatorial Atlantic domain started to increase significantly. During this initial $\\approx$17 Myr-long stretching episode the Pre-salt basin width on the conjugate Br...

  16. Spectroscopic signatures of youth in low-mass kinematic candidates of young moving groups

    CERN Document Server

    Gálvez-Ortiz, M C; Clarke, J R A; Pavlenko, Ya V; Folkes, S L; Pinfield, D J; Jones, H R A; Jenkins, J S; Barnes, J R; Burningham, B; Day-Jones, A C; Martín, E L; Pérez, A E García; del Burgo, C; Pokorny, R S

    2014-01-01

    We present a study of age-related spectral signatures observed in 25 young low-mass objects that we have previously determined as possible kinematic members of five young moving groups: the Local Association (Pleiades moving group, age=20 - 150 Myr), the Ursa Major group (Sirius supercluster, age=300 Myr), the Hyades supercluster (age=600 Myr), IC 2391 supercluster (age=35--55 Myr) and the Castor moving group (age=200 Myr). In this paper we characterize the spectral properties of observed high or low resolution spectra of our kinematic members by fitting theoretical spectral distributions. We study signatures of youth, such as lithium {\\sc i} 6708 \\AA, H$\\alpha$ emission and other age-sensitive spectroscopic signatures in order to confirm the kinematic memberships through age constraints. We find that 21 ($84\\%$) targets show spectroscopic signatures of youth in agreement with the age ranges of the moving group to which membership is implied. For two further objects, age-related constraints remain difficult t...

  17. The warm ionized gas in CALIFA early-type galaxies: 2D emission-line patterns and kinematics for 32 galaxies

    CERN Document Server

    Gomes, J M; Kehrig, C; Vílchez, J M; Lehnert, M D; Sánchez, S F; Ziegler, B; Breda, I; Reis, S N dos; Iglesias-Páramo, J; Bland-Hawthorn, J; Galbany, L; Bomans, D J; Rosales-Ortega, F F; Fernandes, R Cid; Walcher, C J; Falcón-Barroso, J; García-Benito, R; Márquez, I; del Olmo, A; Masegosa, J; Mollá, M; Marino, R A; Delgado, R M González; López-Sánchez, Á R

    2015-01-01

    The morphological, spectroscopic and kinematical properties of the warm interstellar medium (wim) in early-type galaxies (ETGs) hold key observational constraints to nuclear activity and the buildup history of these massive, quiescent systems. High-quality integral field spectroscopy (IFS) data with a wide spectral and spatial coverage, such as those from the CALIFA survey, offer an unprecedented opportunity for advancing our understanding of the wim in ETGs. This article centers on a 2D investigation of the wim component in 32 nearby (<~150Mpc) ETGs from CALIFA, complementing a previous 1D analysis of the same sample (Papaderos et al. 2013; P13). We include here H\\alpha\\ intensity and equivalent width (EW) maps and radial profiles, diagnostic emission-line ratios, besides ionized-gas and stellar kinematics. This study is supplemented by \\tau-ratio maps as an efficient means to quantify the role of photoionization by pAGB stars, as compared to other mechanisms (e.g., AGN, low-level star formation). Additio...

  18. Analysis and Experimental Kinematics of a Skid-Steering Wheeled Robot Based on a Laser Scanner Sensor

    Directory of Open Access Journals (Sweden)

    Tianmiao Wang

    2015-04-01

    Full Text Available Skid-steering mobile robots are widely used because of their simple mechanism and robustness. However, due to the complex wheel-ground interactions and the kinematic constraints, it is a challenge to understand the kinematics and dynamics of such a robotic platform. In this paper, we develop an analysis and experimental kinematic scheme for a skid-steering wheeled vehicle based-on a laser scanner sensor. The kinematics model is established based on the boundedness of the instantaneous centers of rotation (ICR of treads on the 2D motion plane. The kinematic parameters (the ICR coefficient , the path curvature variable  and robot speed , including the effect of vehicle dynamics, are introduced to describe the kinematics model. Then, an exact but costly dynamic model is used and the simulation of this model’s stationary response for the vehicle shows a qualitative relationship for the specified parameters  and . Moreover, the parameters of the kinematic model are determined based-on a laser scanner localization experimental analysis method with a skid-steering robotic platform, Pioneer P3-AT. The relationship between the ICR coefficient  and two physical factors is studied, i.e., the radius of the path curvature  and the robot speed . An empirical function-based relationship between the ICR coefficient of the robot and the path parameters is derived. To validate the obtained results, it is empirically demonstrated that the proposed kinematics model significantly improves the dead-reckoning performance of this skid–steering robot.

  19. Kinematic analysis of cable-driven parallel mechanisms based on minimum potential energy principle

    Directory of Open Access Journals (Sweden)

    Guan Liwen

    2015-12-01

    Full Text Available The forward kinematic analysis of the cable-driven parallel mechanism has been a challenging and interesting problem since 10 years ago. This work converts the forward kinematic analysis problem of the cable-driven parallel mechanism to an optimization problem, whose objective is to minimize the potential energy of mobile platform. In order to simplify the optimization problem further so that it can be solved with any simple optimization algorithm in short time, some constraints are introduced to design variables. We utilize the sequential quadratic programming algorithm to solve the simplified optimization problem in this article. The efficiency and effectiveness of the proposed approach are validated with some numerical examples. Furthermore, due to the fact that a required pose may be not stable, the availability of its inverse kinematic solution should be supervised. The aforementioned approach provides a valid tool for solving this type of problems by contrasting the distinction between the required pose and the actual pose calculated by it. The feasibility of applying our proposed method to execute the inverse kinematic analysis of cable-driven parallel mechanism is proved with several examples in this article.

  20. Dwarf Galaxy Dark Matter Density Profiles Inferred from Stellar and Gas Kinematics

    CERN Document Server

    Adams, Joshua J; Fabricius, Maximilian H; Bosch, Remco C E van den; Barentine, John C; Bender, Ralf; Gebhardt, Karl; Hill, Gary J; Murphy, Jeremy D; Swaters, R A; Thomas, Jens; van de Ven, Glenn

    2014-01-01

    We present new constraints on the density profiles of dark matter (DM) halos in seven nearby dwarf galaxies from measurements of their integrated stellar light and gas kinematics. The gas kinematics of low mass galaxies frequently suggest that they contain constant density DM cores, while N-body simulations instead predict a cuspy profile. We present a data set of high resolution integral field spectroscopy on seven galaxies and measure the stellar and gas kinematics simultaneously. Using Jeans modeling on our full sample, we examine whether gas kinematics in general produce shallower density profiles than are derived from the stars. Although 2/7 galaxies show some localized differences in their rotation curves between the two tracers, estimates of the central logarithmic slope of the DM density profile, gamma, are generally robust. The mean and standard deviation of the logarithmic slope for the population are gamma=0.67+/-0.10 when measured in the stars and gamma=0.58+/-0.24 when measured in the gas. We als...

  1. Spectroscopy and kinematics of low-mass members of young moving groups

    CERN Document Server

    Galvez-Ortiz, M C; Pinfield, D J; Jenkins, J S; Folkes, S L; Perez, A E Garcia; Day-Jones, A C; Burningham, B; Jones, H R A; Barnes, J R; Pokorny, R S

    2010-01-01

    We study a target sample of 68 low-mass objects (with spectral types in the range M4.5-L1) previously selected via photometric and astrometric criteria, as possible members of five young moving groups: the Local Association (Pleiades moving group, age=20 - 150 Myr), the Ursa Mayor group (Sirius supercluster, age=300 Myr), the Hyades supercluster (age=600 Myr), IC 2391 supercluster (age=35 - 55 Myr) and the Castor moving group (age=200 Myr). In this paper we assess their membership by using different kinematic and spectroscopic criteria. We use high resolution echelle spectroscopic observations of the sample to measure accurate radial velocities (RVs). Distances are calculated and compared to those of the moving group from the literature, we also calculate the kinematic Galactic components (U,V,W) of the candidate members and apply kinematic criterion of membership to each group. In addition we measure rotational velocities (v sin i) to place further constraints on membership of kinematic members. We find that...

  2. Kinematic and ground reaction force accommodation during weighted walking.

    Science.gov (United States)

    James, C Roger; Atkins, Lee T; Yang, Hyung Suk; Dufek, Janet S; Bates, Barry T

    2015-12-01

    Weighted walking is a functional activity common in daily life and can influence risks for musculoskeletal loading, injury and falling. Much information exists about weighted walking during military, occupational and recreational tasks, but less is known about strategies used to accommodate to weight carriage typical in daily life. The purposes of the study were to examine the effects of weight carriage on kinematics and peak ground reaction force (GRF) during walking, and explore relationships between these variables. Twenty subjects walked on a treadmill while carrying 0, 44.5 and 89 N weights in front of the body. Peak GRF, sagittal plane joint/segment angular kinematics, stride length and center of mass (COM) vertical displacement were measured. Changes in peak GRF and displacement variables between weight conditions represented accommodation. Effects of weight carriage were tested using analysis of variance. Relationships between peak GRF and kinematic accommodation variables were examined using correlation and regression. Subjects were classified into sub-groups based on peak GRF responses and the correlation analysis was repeated. Weight carriage increased peak GRF by an amount greater than the weight carried, decreased stride length, increased vertical COM displacement, and resulted in a more extended and upright posture, with less hip and trunk displacement during weight acceptance. A GRF increase was associated with decreases in hip extension (|r|=.53, p=.020) and thigh anterior rotation (|r|=.57, p=.009) displacements, and an increase in foot anterior rotation displacement (|r|=.58, p=.008). Sub-group analysis revealed that greater GRF increases were associated with changes at multiple sites, while lesser GRF increases were associated with changes in foot and trunk displacement. Weight carriage affected walking kinematics and revealed different accommodation strategies that could have implications for loading and stability.

  3. Biological constraints do not entail cognitive closure.

    Science.gov (United States)

    Vlerick, Michael

    2014-12-01

    From the premise that our biology imposes cognitive constraints on our epistemic activities, a series of prominent authors--most notably Fodor, Chomsky and McGinn--have argued that we are cognitively closed to certain aspects and properties of the world. Cognitive constraints, they argue, entail cognitive closure. I argue that this is not the case. More precisely, I detect two unwarranted conflations at the core of arguments deriving closure from constraints. The first is a conflation of what I will refer to as 'representation' and 'object of representation'. The second confuses the cognitive scope of the assisted mind for that of the unassisted mind. Cognitive closure, I conclude, cannot be established from pointing out the (uncontroversial) existence of cognitive constraints.

  4. The photogrammetric inner constraints

    Science.gov (United States)

    Dermanis, Athanasios

    A derivation of the complete inner constraints, which are required for obtaining "free network" solutions in close-range photogrammetry, is presented. The inner constraints are derived analytically for the bundle method, by exploiting the fact that the rows of their coefficient matrix from a basis for the null subspace of the design matrix used in the linearized observation equations. The derivation is independent of any particular choice of rotational parameters and examples are given for three types of rotation angles used in photogrammetry, as well as for the Rodriguez elements. A convenient algorithm based on the use of the S-transformation is presented, for the computation of free solutions with either inner or partial inner constraints. This approach is finally compared with alternative approaches to free network solutions.

  5. Psychological constraints on egalitarianism

    DEFF Research Database (Denmark)

    Kasperbauer, Tyler Joshua

    2015-01-01

    Debates over egalitarianism for the most part are not concerned with constraints on achieving an egalitarian society, beyond discussions of the deficiencies of egalitarian theory itself. This paper looks beyond objections to egalitarianism as such and investigates the relevant psychological...... processes motivating people to resist various aspects of egalitarianism. I argue for two theses, one normative and one descriptive. The normative thesis holds that egalitarians must take psychological constraints into account when constructing egalitarian ideals. I draw from non-ideal theories in political...... philosophy, which aim to construct moral goals with current social and political constraints in mind, to argue that human psychology must be part of a non-ideal theory of egalitarianism. The descriptive thesis holds that the most fundamental psychological challenge to egalitarian ideals comes from what...

  6. Constraint algebra in bigravity

    Energy Technology Data Exchange (ETDEWEB)

    Soloviev, V. O., E-mail: Vladimir.Soloviev@ihep.ru [National Research Center Kurchatov Institute, Institute for High Energy Physics (Russian Federation)

    2015-07-15

    The number of degrees of freedom in bigravity theory is found for a potential of general form and also for the potential proposed by de Rham, Gabadadze, and Tolley (dRGT). This aim is pursued via constructing a Hamiltonian formalismand studying the Poisson algebra of constraints. A general potential leads to a theory featuring four first-class constraints generated by general covariance. The vanishing of the respective Hessian is a crucial property of the dRGT potential, and this leads to the appearance of two additional second-class constraints and, hence, to the exclusion of a superfluous degree of freedom—that is, the Boulware—Deser ghost. The use of a method that permits avoiding an explicit expression for the dRGT potential is a distinctive feature of the present study.

  7. Constraints as evolutionary systems

    CERN Document Server

    Rácz, István

    2016-01-01

    The constraint equations for smooth $[n+1]$-dimensional (with $n\\geq 3$) Riemannian or Lorentzian spaces satisfying the Einstein field equations are considered. It is shown, regardless of the signature of the primary space, that the constraints can be put into the form of an evolutionary system comprised either by a first order symmetric hyperbolic system and a parabolic equation or, alternatively, by a strongly hyperbolic system and a subsidiary algebraic relation. In both cases the (local) existence and uniqueness of solutions are also discussed.

  8. Constraint-based scheduling applying constraint programming to scheduling problems

    CERN Document Server

    Baptiste, Philippe; Nuijten, Wim

    2001-01-01

    Constraint Programming is a problem-solving paradigm that establishes a clear distinction between two pivotal aspects of a problem: (1) a precise definition of the constraints that define the problem to be solved and (2) the algorithms and heuristics enabling the selection of decisions to solve the problem. It is because of these capabilities that Constraint Programming is increasingly being employed as a problem-solving tool to solve scheduling problems. Hence the development of Constraint-Based Scheduling as a field of study. The aim of this book is to provide an overview of the most widely used Constraint-Based Scheduling techniques. Following the principles of Constraint Programming, the book consists of three distinct parts: The first chapter introduces the basic principles of Constraint Programming and provides a model of the constraints that are the most often encountered in scheduling problems. Chapters 2, 3, 4, and 5 are focused on the propagation of resource constraints, which usually are responsibl...

  9. Effects of robotically modulating kinematic variability on motor skill learning and motivation.

    Science.gov (United States)

    Duarte, Jaime E; Reinkensmeyer, David J

    2015-04-01

    It is unclear how the variability of kinematic errors experienced during motor training affects skill retention and motivation. We used force fields produced by a haptic robot to modulate the kinematic errors of 30 healthy adults during a period of practice in a virtual simulation of golf putting. On day 1, participants became relatively skilled at putting to a near and far target by first practicing without force fields. On day 2, they warmed up at the task without force fields, then practiced with force fields that either reduced or augmented their kinematic errors and were finally assessed without the force fields active. On day 3, they returned for a long-term assessment, again without force fields. A control group practiced without force fields. We quantified motor skill as the variability in impact velocity at which participants putted the ball. We quantified motivation using a self-reported, standardized scale. Only individuals who were initially less skilled benefited from training; for these people, practicing with reduced kinematic variability improved skill more than practicing in the control condition. This reduced kinematic variability also improved self-reports of competence and satisfaction. Practice with increased kinematic variability worsened these self-reports as well as enjoyment. These negative motivational effects persisted on day 3 in a way that was uncorrelated with actual skill. In summary, robotically reducing kinematic errors in a golf putting training session improved putting skill more for less skilled putters. Robotically increasing kinematic errors had no performance effect, but decreased motivation in a persistent way.

  10. KINEMATIC AND SPATIAL SUBSTRUCTURE IN NGC 2264

    Energy Technology Data Exchange (ETDEWEB)

    Tobin, John J. [Hubble Fellow, National Radio Astronomy Observatory, Charlottesville, VA 22903 (United States); Hartmann, Lee; Hsu, Wen-Hsin; Mateo, Mario [Department of Astronomy, University of Michigan, Ann Arbor, MI 48109 (United States); Fűrész, Gabor, E-mail: tobin@strw.leidenuniv.nl [Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)

    2015-04-15

    We present an expanded kinematic study of the young cluster NGC 2264 based upon optical radial velocities measured using multi-fiber echelle spectroscopy at the 6.5 m MMT and Magellan telescopes. We report radial velocities for 695 stars, of which approximately 407 stars are confirmed or very likely members. Our results more than double the number of members with radial velocities from Fűrész et al., resulting in a much better defined kinematic relationship between the stellar population and the associated molecular gas. In particular, we find that there is a significant subset of stars that are systematically blueshifted with respect to the molecular ({sup 13}CO) gas. The detection of Lithium absorption and/or infrared excesses in this blueshifted population suggests that at least some of these stars are cluster members; we suggest some speculative scenarios to explain their kinematics. Our results also more clearly define the redshifted population of stars in the northern end of the cluster; we suggest that the stellar and gas kinematics of this region are the result of a bubble driven by the wind from O7 star S Mon. Our results emphasize the complexity of the spatial and kinematic structure of NGC 2264, important for eventually building up a comprehensive picture of cluster formation.

  11. Inverse kinematic-based robot control

    Science.gov (United States)

    Wolovich, W. A.; Flueckiger, K. F.

    1987-01-01

    A fundamental problem which must be resolved in virtually all non-trivial robotic operations is the well-known inverse kinematic question. More specifically, most of the tasks which robots are called upon to perform are specified in Cartesian (x,y,z) space, such as simple tracking along one or more straight line paths or following a specified surfacer with compliant force sensors and/or visual feedback. In all cases, control is actually implemented through coordinated motion of the various links which comprise the manipulator; i.e., in link space. As a consequence, the control computer of every sophisticated anthropomorphic robot must contain provisions for solving the inverse kinematic problem which, in the case of simple, non-redundant position control, involves the determination of the first three link angles, theta sub 1, theta sub 2, and theta sub 3, which produce a desired wrist origin position P sub xw, P sub yw, and P sub zw at the end of link 3 relative to some fixed base frame. Researchers outline a new inverse kinematic solution and demonstrate its potential via some recent computer simulations. They also compare it to current inverse kinematic methods and outline some of the remaining problems which will be addressed in order to render it fully operational. Also discussed are a number of practical consequences of this technique beyond its obvious use in solving the inverse kinematic question.

  12. Consideration of Photon Radiation in Kinematic Fits for Future e+ e- Colliders

    CERN Document Server

    Beckmann, Moritz; List, Jenny

    2010-01-01

    Kinematic fitting is an important tool to improve the resolution in high-energy physics experiments. At future e+e- colliders, photon radiation parallel to the beam carrying away large amounts of energy and momentum will become a challenge for kinematic fitting. A photon with longitudinal momentum pz({\\eta}) is introduced, which is parametrized such that {\\eta} follows a normal distribution. In the fit, {\\eta} is treated as having a measured value of zero, which corresponds to pz = 0. As a result, fits with constraints on energy and momentum conservation converge well even in the presence of a highly energetic photon, while the resolution of fits without such a photon is retained. A fully simulated and reconstructed e+e- -> qqqq event sample at sqrt(s) = 500 GeV is used to investigate the performance of this method under realistic conditions, as expected at the International Linear Collider.

  13. Kinematic and Dynamic Simulation Analysis of Hydraulic Excavator’s Working Equipment based on ADAMS

    Directory of Open Access Journals (Sweden)

    Yu Hong Yan

    2016-01-01

    Full Text Available This paper establishes the 3D excavator model according to the actual size in UG firstly. Then based on the virtual simulation software ADAMS, the virtual prototype of the working device is built by adding interrelated constraints(kinematic pair and hydraulic cylinder driving function and load secondly. This paper gets the main parameters of the excavator working scope and the pressure situation change curves of point of each hydraulic cylinder by making kinematic and dynamic simulation analysis of hydraulic excavator’s working equipment at last. The conclusion providing design theory and improvement for the excavator’s working device, which also play an important role in improving the level of China’s excavator design, enhancing excavator’s performance and promoting the rapid development of excavator industry.

  14. Kinematic Analysis of a Serial - Parallel Machine Tool: the VERNE machine

    CERN Document Server

    Kanaan, Daniel; Chablat, Damien; 10.1016/j.mechmachtheory.2008.03.002

    2008-01-01

    The paper derives the inverse and the forward kinematic equations of a serial - parallel 5-axis machine tool: the VERNE machine. This machine is composed of a three-degree-of-freedom (DOF) parallel module and a two-DOF serial tilting table. The parallel module consists of a moving platform that is connected to a fixed base by three non-identical legs. These legs are connected in a way that the combined effects of the three legs lead to an over-constrained mechanism with complex motion. This motion is defined as a simultaneous combination of rotation and translation. In this paper we propose symbolical methods that able to calculate all kinematic solutions and identify the acceptable one by adding analytical constraint on the disposition of legs of the parallel module.

  15. Space reconstruction of the morphology and kinematics of axisymmetric radio sources

    CERN Document Server

    Diep, P N; Hoai, D T; Nhung, P T; Thao, N T; Tuan-Anh, P; Darriulat, P

    2016-01-01

    The unprecedented quality of the observations available from the Atacama Large Millimetre/sub-millimetre Array (ALMA) calls for analysis methods making the best of them. Reconstructing in space the morphology and kinematics of radio sources is an underdetermined problem that requires imposing additional constraints for its solution. The hypothesis of rotational invariance about a well-defined star axis, which is a good approximation to the description of the gas envelopes of many evolved stars and protostars, is particularly efficient in this role. In the first part of the article, a systematic use of simulated observations allows for identifying the main problems and for constructing quantities aimed at solving them. In particular the evaluation of the orientation of the star axis in space and the differentiation between expansion along the star axis and rotation about it are given special attention. The use of polar rather than Cartesian sky coordinates is shown to better match the morphology and kinematics...

  16. Constraint Optimization Literature Review

    Science.gov (United States)

    2015-11-01

    COPs. 15. SUBJECT TERMS high-performance computing, mobile ad hoc network, optimization, constraint, satisfaction 16. SECURITY CLASSIFICATION OF: 17...France): INRA Editions; 1996. p. 111–150. Black PE. Branch-and-bound. US national institute of standards and technology dictionary of algorithms

  17. Mining Matters : Natural Resource Extraction and Local Business Constraints

    NARCIS (Netherlands)

    de Haas, Ralph; Poelhekke, Steven

    2016-01-01

    We estimate the impact of local mining activity on the business constraints experienced by 22,150 firms across eight resource-rich countries. We find that with the presence of active mines, the business environment in the immediate vicinity (<20 km) of a firm deteriorates but business constraints of

  18. Kinematics of the most efficient cilium

    CERN Document Server

    Eloy, Christophe

    2012-01-01

    In a variety of biological processes, eukaryotic cells use cilia to transport flow. Although cilia have a remarkably conserved internal molecular structure, experimental observations report very diverse kinematics. To address this diversity, we determine numerically the kinematics and energetics of the most efficient cilium. Specifically, we compute the time-periodic deformation of a wall-bound elastic filament leading to transport of a surrounding fluid at minimum energetic cost, where the cost is taken to be the positive work done by all internal molecular motors. The optimal kinematics are found to strongly depend on the cilium bending rigidity through a single dimensionless number, the Sperm number, and closely resemble the two-stroke ciliary beating pattern observed experimentally.

  19. Identifying the Isomorphism of Kinematic Chains

    Directory of Open Access Journals (Sweden)

    Romaniak Krystyna

    2016-09-01

    Full Text Available Identification of isomorphic kinematic chains is one of the key issues in researching the structure of mechanisms. As a result the structures which duplicate are eliminated and further research is carried out on kinematic chains that do not duplicate. This dilemma has been taken up by many scholars who have come up with a variety of ideas how to solve it. The review of the methods for identifying the isomorphism of kinematic chains suggested by researchers is contained in this study, including Hamming Number Technique, eigenvalues and eigenvectors, perimeter graphs, dividing and matching vertices. The spectrum of methods applied to the issue of identifying the iso-morphism of mechanisms reflects the researchers’ efforts to obtain a precise result in the shortest time possible.

  20. Kinematic Model-Based Pedestrian Dead Reckoning for Heading Correction and Lower Body Motion Tracking

    Directory of Open Access Journals (Sweden)

    Min Su Lee

    2015-11-01

    Full Text Available In this paper, we present a method for finding the enhanced heading and position of pedestrians by fusing the Zero velocity UPdaTe (ZUPT-based pedestrian dead reckoning (PDR and the kinematic constraints of the lower human body. ZUPT is a well known algorithm for PDR, and provides a sufficiently accurate position solution for short term periods, but it cannot guarantee a stable and reliable heading because it suffers from magnetic disturbance in determining heading angles, which degrades the overall position accuracy as time passes. The basic idea of the proposed algorithm is integrating the left and right foot positions obtained by ZUPTs with the heading and position information from an IMU mounted on the waist. To integrate this information, a kinematic model of the lower human body, which is calculated by using orientation sensors mounted on both thighs and calves, is adopted. We note that the position of the left and right feet cannot be apart because of the kinematic constraints of the body, so the kinematic model generates new measurements for the waist position. The Extended Kalman Filter (EKF on the waist data that estimates and corrects error states uses these measurements and magnetic heading measurements, which enhances the heading accuracy. The updated position information is fed into the foot mounted sensors, and reupdate processes are performed to correct the position error of each foot. The proposed update-reupdate technique consequently ensures improved observability of error states and position accuracy. Moreover, the proposed method provides all the information about the lower human body, so that it can be applied more effectively to motion tracking. The effectiveness of the proposed algorithm is verified via experimental results, which show that a 1.25% Return Position Error (RPE with respect to walking distance is achieved.

  1. SMACK - SMOOTHING FOR AIRCRAFT KINEMATICS

    Science.gov (United States)

    Bach, R.

    1994-01-01

    The computer program SMACK (SMoothing for AirCraft Kinematics) is designed to provide flightpath reconstruction of aircraft forces and motions from measurements that are noisy or incomplete. Additionally, SMACK provides a check on instrument accuracy and data consistency. The program can be used to analyze data from flight-test experiments prior to their use in performance, stability and control, or aerodynamic modeling calculations. It can also be used in the analysis of aircraft accidents, where the actual forces and motions may have to be determined from a very limited data set. Application of a state-estimation method for flightpath reconstruction is possible because aircraft forces and motions are related by well-known equations of motion. The task of postflight state estimation is known as a nonlinear, fixed-interval smoothing problem. SMACK utilizes a backward-filter, forward-smoother algorithm to solve the problem. The equations of motion are used to produce estimates that are compared with their corresponding measurement time histories. The procedure is iterative, providing improved state estimates until a minimum squared-error measure is achieved. In the SMACK program, the state and measurement models together represent a finite-difference approximation for the six-degree-of-freedom dynamics of a rigid body. The models are used to generate time histories which are likely to be found in a flight-test measurement set. These include onboard variables such as Euler angles, angular rates, and linear accelerations as well as tracking variables such as slant range, bearing, and elevation. Any bias or scale-factor errors associated with the state or measurement models are appended to the state vector and treated as constant but unknown parameters. The SMACK documentation covers the derivation of the solution algorithm, describes the state and measurement models, and presents several application examples that should help the analyst recognize the potential

  2. Autonomous gliding entry guidance with geographic constraints

    Institute of Scientific and Technical Information of China (English)

    Guo Jie; Wu Xuzhong; Tang Shengjing

    2015-01-01

    This paper presents a novel three-dimensional autonomous entry guidance for relatively high lift-to-drag ratio vehicles satisfying geographic constraints and other path constraints. The guidance is composed of onboard trajectory planning and robust trajectory tracking. For trajectory planning, a longitudinal sub-planner is introduced to generate a feasible drag-versus-energy profile by using the interpolation between upper boundary and lower boundary of entry corridor to get the desired trajectory length. The associated magnitude of the bank angle can be specified by drag profile, while the sign of bank angle is determined by lateral sub-planner. Two-reverse mode is utilized to satisfy waypoint constraints and dynamic heading error corridor is utilized to satisfy no-fly zone constraints. The longitudinal and lateral sub-planners are iteratively employed until all of the path constraints are satisfied. For trajectory tracking, a novel tracking law based on the active disturbance rejection control is introduced. Finally, adaptability tests and Monte Carlo simulations of the entry guidance approach are performed. Results show that the proposed entry guidance approach can adapt to different entry missions and is able to make the vehicle reach the prescribed target point precisely in spite of geographic constraints.

  3. The Kinematic Theory of Solar Dynamo

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Generation of the Sun's magnetic fields by self-inductive processes inthe solar electrically conducting interior, the solar dynamo theory, is a fundamen-tally important subject in astrophysics. The kinematic dynamo theory concernshow the magnetic fields are produced by kinematically possible flows without beingconstrained by the dynamic equation. We review a number of basic aspects of thekinematic dynamo theory, including the magnetohydrodynamic approximation forthe dynamo equation, the impossibility of dynamo action with the solar differentialrotation, the Cowling's anti-dynamo theorem in the solar context, the turbulent al-pha effect and recently constructed three-dimensional interface dynamos controlledby the solar tachocline at the base of the convection zone.

  4. H$\\alpha$ kinematics of KPG 390

    CERN Document Server

    Repetto, P; Fuentes-Carrera, R Gabbasov I

    2009-01-01

    In this work we present scanning Fabry-Perot H$\\alpha$ observations of the isolated interacting galaxy pair NGC 5278/79 obtained with the PUMA Fabry-Perot interferometer. We derived velocity fields, various kinematic parameters and rotation curves for both galaxies. Our kinematical results together with the fact that dust lanes have been detected in both galaxies, as well as the analysis of surface brightness profiles along the minor axis, allowed us to determine that both components of the interacting pair are trailing spirals.

  5. Kinematic Distance of Galactic Planetary Nebulae

    CERN Document Server

    Yang, A Y; Zhu, H; Leahy, D A; Wu, D

    2016-01-01

    We construct \\HI~absorption spectra for 18 planetary nebulae (PNe) and their background sources using the data from the International Galactic Plane Survey. We estimate the kinematic distances of these PNe, among which 15 objects' kinematic distances are obtained for the first time. The distance uncertainties of 13 PNe range from 10% to 50%, which is a significant improvement with uncertainties of a factor two or three smaller than most of previous distance measurements. We confirm that PN G030.2-00.1 is not a PN because of its large distance found here.

  6. Structure and Kinematics of the Indo-Burmese Wedge

    Science.gov (United States)

    Maurin, T.; Rangin, C.

    2007-12-01

    The Burma subduction trench and the associated Indo Burmese wedge mark the present eastern boundary of the Indian plate in the northern Bengal area. The initiation, duration and history of the Bengal crust subduction beneath Burma is still debated. The aim of this paper is to provide a structural and kinematic analysis of the Indo- Burmese wedge in order to better constraints the Bengal crust subduction history beneath Burma. On the basis of field observations, seismic reflection data interpretation and well logs data we present a structural analysis of the Outer Indo-Burmese Wedge. We also constrain the onset of this Outer Wedge to be younger than 2Ma, implying a recent and fast westward growth (~10cm/yr) since Late Pliocene in close relationship with the onset of the Shillong plateau. Restoration process of a synthetic cross section through the Outer Wedge allowed us to estimate the amount of EW shortening accommodated in the Outer Wedge to be 5.1mm/yr since 2Ma. These results combined with previous available GPS data from central Myanmar suggest strain partitioning at wedge scale. The core of the wedge is affected by shear deformation and acts as a buttress for a frontal wedge that accommodates a more compressive strain component. Finally we propose that the main characteristic of the Indo-Burmese wedge growth mechanism is the progressive incorporation of the most internal part of the wedge, formerly affected by transpressive thin-skinned tectonics, to the buttress where they are subsequently affected by shear deformation. The crustal structure boarding the newly formed buttress seems to be guided by the subducting crust fabrics. We are in favour of a very recent (Late Miocene) onset of the present Indian crust subduction beneath Burma coeval with the global plate kinematics reorganisation related to the Indian/Australian plate spliting. This subduction postdates the Indo Burmese range onset that must have started in early Miocene. This range first began to

  7. A constraint algorithm for singular Lagrangians subjected to nonholonomic constraints

    Energy Technology Data Exchange (ETDEWEB)

    de Leon, M. [Instituto de Matematicas y Fisica Fundamental, Consejo Superior de Investigaciones Cientificas, Serrano 123, 28006 Madrid (Spain); de Diego, D.M. [Departamento de Economia Aplicada Cuantitativa, Facultad de Ciencias Economicas y Empresariales, UNED, 28040 Madrid (Spain)

    1997-06-01

    We construct a constraint algorithm for singular Lagrangian systems subjected to nonholonomic constraints which generalizes that of Dirac for constrained Hamiltonian systems. {copyright} {ital 1997 American Institute of Physics.}

  8. Ionized gas kinematics of galaxies in the CALIFA survey I: Velocity fields, kinematic parameters of the dominant component, and presence of kinematically distinct gaseous systems

    CERN Document Server

    Garcia-Lorenzo, B; Barrera-Ballesteros, J K; Masegosa, J; Husemann, B; Falcón-Barroso, J; Lyubenova, M; Sanchez, S F; Walcher, J; Mast, D; Garcia-Benito, R; Mendez-Abreu, J; van de Ven, G; Spekkens, K; Holmes, L; Monreal-Ibero, A; del Olmo, A; Ziegler, B; Bland-Hawthorn, J; Sanchez-Blazquez, P; Iglesias-Paramo, J; Aguerri, J A L; Papaderos, P; Gomes, J M; Marino, R A; Delgado, R M Gonzalez; Cortijo-Ferrero, C; Lopez-Sanchez, A R; Bekeraite, S; Wisotzki, L; Bomans, D

    2014-01-01

    This work provides an overall characterization of the kinematic behavior of the ionized gas of the galaxies included in the Calar Alto Legacy Integral field Area (CALIFA), offering kinematic clues to potential users of this survey for including kinematical criteria for specific studies. From the first 200 galaxies observed by CALIFA, we present the 2D kinematic view of the 177 galaxies satisfying a gas detection threshold. After removing the stellar contribution, we used the cross-correlation technique to obtain the radial velocity of the dominant gaseous component. The main kinematic parameters were directly derived from the radial velocities with no assumptions on the internal motions. Evidence of the presence of several gaseous components with different kinematics were detected by using [OIII] profiles. Most objects in the sample show regular velocity fields, although the ionized-gas kinematics are rarely consistent with simple coplanar circular motions. 35% of the objects present evidence of a displacemen...

  9. Lower limb kinematic variability in dancers performing drop landings onto floor surfaces with varied mechanical properties.

    Science.gov (United States)

    Reeve, Helen K; Hopper, Luke S; Elliott, Bruce C; Ackland, Timothy R

    2013-08-01

    Elite dancers perform highly skilled and consistent movements. These movements require effective regulation of the intrinsic and extrinsic forces acting within and on the body. Customized, compliant floors typically used in dance are assumed to enhance dance performance and reduce injury risk by dampening ground reaction forces during tasks such as landings. As floor compliance can affect the extrinsic forces applied to the body, secondary effects of floor properties may be observed in the movement consistency or kinematic variability exhibited during dance performance. The aim of this study was to investigate the effects of floor mechanical properties on lower extremity kinematic variability in dancers performing landing tasks. A vector coding technique was used to analyze sagittal plane knee and ankle joint kinematic variability, in a cohort of 12 pre-professional dancers, through discrete phases of drop landings from a height of 0.2m. No effect on kinematic variability was observed between floors, indicating that dancers could accommodate the changing extrinsic floor conditions. Future research may consider repeat analysis under more dynamic task constraints with a less experienced cohort. However, knee/ankle joint kinematic variability was observed to increase late in the landing phase which was predominantly comprised of knee flexion coupled with the terminal range of ankle dorsiflexion. These findings may be the result of greater neural input late in the landing phase as opposed to the suggested passive mechanical interaction of the foot and ankle complex at initial contact with a floor. Analysis of joint coordination in discrete movement phases may be of benefit in identifying intrinsic sources of variability in dynamic tasks that involve multiple movement phases.

  10. kinematics of nearby galaxies using Fabry-Perot and IFU data

    Science.gov (United States)

    Erroz-Ferrer, Santiago; S4G Team; MUSE-GTO Consortium

    2017-03-01

    I present here analysis of the shapes of the rotation curves of a large sample of nearby spiral galaxies with high angular and spectral resolution Hα (Fabry-Perot GHαFaS) kinematics, and the resulting constraints on their total mass distributions. In particular I discuss how their rotation curve shapes relate to key galaxy properties. Finally I present related results from the MUSE Atlas of Disks (MAD) program, which is dissecting the nearby disk population with IFU spectroscopy at ~100pc resolution.

  11. Kinematics and Dynamics of a Translational Parallel Robot Based on Planar Mechanisms

    Directory of Open Access Journals (Sweden)

    Mario A. Garcia-Murillo

    2016-11-01

    Full Text Available In this contribution, a novel translational parallel robot composed of an arrangement of mechanisms with planar motion is presented. Its mobility is analyzed and the position analysis is solved by using equations derived from mechanical constraints. Furthermore, the analysis of velocity and acceleration are solved by means of the screw theory. For completeness, the inverse dynamics are also presented and solved by means of an interesting combination of the screw theory and the virtual work principle. Finally, a numerical example is included to show the application of the kinematic model, which is verified with the aid of a commercially available software.

  12. The complexity of South China Sea kinematics

    Science.gov (United States)

    Sibuet, Jean-Claude; Gao, Jinyao; Zhao, Minghui; Wu, Jonny; Ding, Weiwei; Yeh, Yi-Ching; Lee, Chao-Shing

    2016-04-01

    Magnetic modeling shows that the age of the youngest South China Sea (SCS) oceanic crust is controversial (e.g. 15.5 Ma, Briais et al., JGR 1993 and 20.5 Ma, Barckhausen et al., MPG 2014). Close to the rift axis of the East sub-basin, Ar-Ar age dating of oceanic crustal rocks collected during IODP Leg 349 gives ages of 15 and 15.2 +/- 0.2 Ma (Koppers, Fall AGU meeting, 2014), which seems to favor the 15.5 Ma age given by Briais et al. modeling. However, basaltic samples might belong to a sill and not to the typical oceanic crust. As post-spreading magmatic activity (~8-13 Ma) largely masks the spreading fabric, in particular near the previously identified E-W portion of the extinct ridge axis of the East sub-basin, the published locations of the axial magnetic anomaly and spreading rates are incorrect. The compilation of available swath bathymetric data shows that if post-spreading volcanics hide the seafloor spreading magnetic fabric mostly along and near the extinct spreading axis, the whole SCS is globally characterized by rift directions following three directions: N055°in the youngest portion of the SCS, N065° and N085° in the oldest portions of the SCS (Sibuet et al., Tectonophysics 2016) suggesting the extinct ridge axis is N055° trending instead of E-W. We present an updated version of the whole SCS structural sketch based on previously published swath bathymetric trends and new detailed magnetic lineations trends compiled from an extremely dense set of magnetic data. The new structural sketch shows: - The distribution of conjugate kinematic domains, - The early opening of the NW and East sub-basins, before a jump of the rift axis, - A second ridge jump in the East basin, - The different expressions of the post-spreading magmatism in the East and SW sub-basins. In the East sub-basin, crustal magmatic intrusions led to the formation of extrusive basalts associated with the presence of numerous volcanoes (Wang et al., Geological Journal 2016). In the SW

  13. Dynamical Constraints on Exoplanets

    CERN Document Server

    Horner, Jonti; Tinney, Chris; Hinse, Tobias C; Marshall, Jonathan P

    2013-01-01

    Dynamical studies of new exoplanet systems are a critical component of the discovery and characterisation process. Such studies can provide firmer constraints on the parameters of the newly discovered planets, and may even reveal that the proposed planets do not stand up to dynamical scrutiny. Here, we demonstrate how dynamical studies can assist the characterisation of such systems through two examples: QS Virginis and HD 73526.

  14. (non) Emergent Constraints

    Science.gov (United States)

    Jackson, C. S.; Hattab, M. W.; Huerta, G.

    2014-12-01

    Emergent constraints are observable quantities that provide some physical basis for testing or predicting how a climate model will respond to greenhouse gas forcing. Very few such constraints have been identified for the multi-model CMIP archive. Here we explore the question of whether constraints that apply to a single model, a perturbed parameter ensemble (PPE) of the Community Atmosphere Model (CAM3.1), can be applied to predicting the climate sensitivities of models within the CMIP archive. In particular we construct our predictive patterns from multivariate EOFs of the CAM3.1 ensemble control climate. Multiple regressive statistical models were created that do an excellent job of predicting CAM3.1 sensitivity to greenhouse gas forcing. However, these same patterns fail spectacularly to predict sensitivities of models within the CMIP archive. We attribute this failure to several factors. First, and perhaps the most important, is that the structures affecting climate sensitivity in CAM3.1 have a unique signature in the space of our multivariate EOF patterns that are unlike any other climate model. That is to say, we should not expect CAM3.1 to represent the way another models within CMIP archive respond to greenhouse gas forcing. The second, perhaps related, reason is that the CAM3.1 PPE does a poor job of spanning the range of climates and responses found within the CMIP archive. We shall discuss the implications of these results for the prospect of finding emergent constraints within the CMIP archive. We will also discuss what this may mean for establishing uncertainties in climate projections.

  15. The NCL natural constraint language

    CERN Document Server

    Zhou, Jianyang

    2012-01-01

    This book presents the Natural Constraint Language (NCL) language, a description language in conventional mathematical logic for modeling and solving constraint satisfaction problems. It uses illustrations and tutorials to detail NCL and its applications.

  16. Constraints on the optical depth of galaxy groups and clusters

    CERN Document Server

    Flender, Samuel; McDonald, Michael

    2016-01-01

    Future data from galaxy redshift surveys, combined with high-resolutions maps of the cosmic microwave background, will enable measurements of the pairwise kinematic Sunyaev-Zel'dovich (kSZ) signal with unprecedented statistical significance. This signal probes the matter-velocity correlation function, scaled by the average optical depth ($\\tau$) of the galaxy groups and clusters in the sample, and is thus of fundamental importance for cosmology. However, in order to translate pairwise kSZ measurements into cosmological constraints, external constraints on $\\tau$ are necessary. In this work, we present a new model for the intra-cluster medium, which takes into account star-formation, feedback, non-thermal pressure, and gas cooling. Our semi-analytic model is computationally efficient and can reproduce results of recent hydrodynamical simulations of galaxy cluster formation. By calibrating the model using recent X-ray measurements of gas density profiles of clusters and $M_{\\mathrm{gas}}-M$ relations of groups ...

  17. Constraints on Relaxion Windows

    CERN Document Server

    Choi, Kiwoon

    2016-01-01

    We examine low energy phenomenology of the relaxion solution to the weak scale hierarchy problem. Assuming that the Hubble friction is responsible for the dissipation of relaxion energy, we identify the cosmological relaxion window which corresponds to the parameter region compatible with a given value of the acceptable number of inflationary $e$-foldings. We then discuss a variety of observational constraints on the relaxion window, while focusing on the case that the barrier potential to stabilize the relaxion is induced by new physics, rather than by low energy QCD dynamics. We find that majority of the parameter space with a relaxion mass $m_\\phi\\gtrsim 100$ eV or a relaxion decay constant $f\\lesssim 10^7$ GeV is excluded by existing constraints. There is an interesting small parameter region with $m_\\phi\\sim \\,0.2-1$ GeV and $f\\sim\\, {\\rm few}-10$ TeV, which is allowed by existing constraints, but can be probed soon by future beam dump experiment such as the SHiP experiment, or by improved EDM experiment...

  18. KINEMATICS OF 13 BRIGHTEST CLUSTER GALAXIES

    NARCIS (Netherlands)

    FISHER, D; ILLINGWORTH, G; FRANX, M

    1995-01-01

    Velocity dispersion profiles and rotation curves have been determined for a sample of 13 brightest duster galaxies (BCGs) in order to study their internal stellar kinematics and investigate their relationship to ellipticals. We find that BCGs generally display velocity dispersion profiles with gradi

  19. Kinematics of shot-geophone migration

    NARCIS (Netherlands)

    C.C. Stolk; M.V. de Hoop; W.W. Symes

    2009-01-01

    Recent analysis and synthetic examples have shown that many prestack depth migration methods produce nonflat image gathers containing spurious events, even when provided with a kinematically correct migration velocity field, if this velocity field is highly refractive. This pathology occurs in all m

  20. Kinematic structures in galactic disc simulations

    NARCIS (Netherlands)

    Roca-F� brega, S.; Romero-Gómez, M.; Figueras, F.; Antoja Castelltort, Teresa; Valenzuela, O.; Henney, W.J.; Torres-Peimbert, S.

    2011-01-01

    N-body and test particle simulations have been used to characterize the stellar streams in the galactic discs of Milky Way type galaxies. Tools such as the second and third order moments of the velocity ellipsoid and clustering methods -EM-WEKA and FoF- allow characterizing these kinematic structure

  1. Kinematic artifacts in prestack depth migration.

    NARCIS (Netherlands)

    Stolk, C.C.; Symes, W.W.

    2004-01-01

    Strong refraction of waves in the migration velocity model introduces kinematic artifacts¿coherent events not corresponding to actual reflectors¿into the image volumes produced by prestack depth migration applied to individual data bins. Because individual bins are migrated independently, the migrat

  2. Action experience changes attention to kinematic cues

    Directory of Open Access Journals (Sweden)

    Courtney eFilippi

    2016-02-01

    Full Text Available The current study used remote corneal reflection eye-tracking to examine the relationship between motor experience and action anticipation in 13-month-old infants. To measure online anticipation of actions infants watched videos where the actor’s hand provided kinematic information (in its orientation about the type of object that the actor was going to reach for. The actor’s hand orientation either matched the orientation of a rod (congruent cue or did not match the orientation of the rod (incongruent cue. To examine relations between motor experience and action anticipation, we used a 2 (reach first vs. observe first x 2 (congruent kinematic cue vs. incongruent kinematic cue between-subjects design. We show that 13-month-old infants in the observe first condition spontaneously generate rapid online visual predictions to congruent hand orientation cues and do not visually anticipate when presented incongruent cues. We further demonstrate that the speed that these infants generate predictions to congruent motor cues is correlated with their own ability to pre-shape their hands. Finally, we demonstrate that following reaching experience, infants generate rapid predictions to both congruent and incongruent hand shape cues—suggesting that short-term experience changes attention to kinematics.

  3. KINEMATIC DISTANCE ASSIGNMENTS WITH H I ABSORPTION

    Energy Technology Data Exchange (ETDEWEB)

    Jones, Courtney; Dickey, John M. [School of Mathematics and Physics, Private Bag 37, University of Tasmania, Hobart 7000 (Australia)

    2012-07-01

    Using H I absorption spectra from the International Galactic Plane Survey, a new method is implemented to resolve the kinematic distance ambiguity for 75 H II regions with known systemic velocities from radio recombination lines. A further 40 kinematic distance determinations are made for H II region candidates without known systemic velocities through an investigation of the presence of H I absorption around the terminal velocity. New kinematic distance determinations can be used to further constrain spiral arm parameters and the location and extent of other structures in the Milky Way disk. H I absorption toward continuum sources beyond the solar circle is also investigated. Follow-up studies of H I at higher resolution than the 1' to 2' of existing Galactic Plane Surveys will provide kinematic distances to many more H II regions on the far side of the Galactic center. On the basis of the velocity channel summation technique developed in this paper, a much larger sample of H II regions will be analyzed in a future paper to remove the near-far distance ambiguity.

  4. 基于ADAMS的助力型外骨骼特征动作驱动液压缸运动学研究%Kinematics research of exoskeleton characteristic action activated hydraulic cylinders based on ADAMS

    Institute of Scientific and Technical Information of China (English)

    李贤坤; 刘放; 迟振华; 赵兴忠

    2014-01-01

    以助力型外骨骼为研究对象,以建立助力型外骨骼运动学模型以及分析外骨骼运动学特性为研究目标,以运动生物力学为基础,选择单膝下跪-起立动作为特征动作,采用多层次光学捕捉系统采集人体运动数据,采用多波峰(波谷)最小二乘法进行数据拟合,得到人体运动时特征角度的数学模型。助力型外骨骼在完成动作时需要与人体高度偕行,因此将特征角度的数学模型运用到助力型外骨骼中,建立外骨骼三维模型,在ADAMS软件中完成外骨骼特征动作仿真,以此来分析外骨骼运动学特性。%Choose help exoskeleton for the study in order to establish the modeling of the assist -type exoskeleton and analytical ki-nematics characteristic of exoskeleton .Based on sports biomechanics ,select one knee-stand up action for characterized action .Use multi-level optical capture system to capture human motion data , and multi-peak ( trough ) method of least squares to fit data . Therefor get the mathematical model of the human motion characteristic angle .Help exoskeleton complete the characteristic action with body accompanying ,then the mathematical model of characterized angle must be used to help exoskeleton .Establish three-di-mensional model of the help exoskeleton ,and simulation the characterized action of help exoskeleton in ADAMS to analyze the ex-oskeleton kinematics .

  5. Loop theory and applications to some key problems of kinematic structure of kinematic chains

    Institute of Scientific and Technical Information of China (English)

    Huafeng DING; Zhen HUANG

    2009-01-01

    Structure synthesis of mechanisms is a pivotal issue in the field of mechanical innovation and mechanical conceptual design. In this paper, a new loop theory of kinematic chains is proposed. Based on this theory, some key problems that hamper computer-based automatic synthesis of mechanisms are solved. 1) The open problem of isomorphism of kinematic chains that has lasted for more than four decades is successfully solved. 2) A new rigid sub-chain detection method that is especially suitable for complex chains is proposed. 3) The characteristic representation code remains the same even if the drawing modes and labeling ways of a chain are changed, and an atlas database of kinematic chains is established. The multi-value problem for the representation of kinematic chains is solved. The results in this paper will benefit the digitization and computerization of mechanical conceptual design.

  6. Current deformation in Central Afar and triple junction kinematics deduced from GPS and InSAR measurements

    Science.gov (United States)

    Doubre, Cécile; Déprez, Aline; Masson, Frédéric; Socquet, Anne; Lewi, Elias; Grandin, Raphaël; Nercessian, Alexandre; Ulrich, Patrice; De Chabalier, Jean-Bernard; Saad, Ibrahim; Abayazid, Ahmadine; Peltzer, Gilles; Delorme, Arthur; Calais, Eric; Wright, Tim

    2017-02-01

    Kinematics of divergent boundaries and Rift-Rift-Rift junctions are classically studied using long-term geodetic observations. Since significant magma-related displacements are expected, short-term deformation provides important constraints on the crustal mechanisms involved both in active rifting and in transfer of extensional deformation between spreading axes. Using InSAR and GPS data, we analyse the surface deformation in the whole Central Afar region in detail, focusing on both the extensional deformation across the Quaternary magmato-tectonic rift segments, and on the zones of deformation transfer between active segments and spreading axes. The largest deformation occurs across the two recently activated Asal-Ghoubbet (AG) and Manda Hararo-Dabbahu (MH-D) magmato-tectonic segments with very high strain rates, whereas the other Quaternary active segments do not concentrate any large strain, suggesting that these rifts are either sealed during interdyking periods or not mature enough to remain a plate boundary. Outside of these segments, the GPS horizontal velocity field shows a regular gradient following a clockwise rotation of the displacements from the Southeast to the East of Afar, with respect to Nubia. Very few shallow creeping structures can be identified as well in the InSAR data. However, using these data together with the strain rate tensor and the rotations rates deduced from GPS baselines, the present-day strain field over Central Afar is consistent with the main tectonic structures, and therefore with the long-term deformation. We investigate the current kinematics of the triple junction included in our GPS data set by building simple block models. The deformation in Central Afar can be described by adding a central microblock evolving separately from the three surrounding plates. In this model, the northern block boundary corresponds to a deep EW-trending trans-tensional dislocation, locked from the surface to 10-13 km and joining at depth the

  7. A New Topological Description Method of Kinematic Chain

    Institute of Scientific and Technical Information of China (English)

    Ding Huafeng; Huang Zhen; Cao Yi

    2004-01-01

    This paper presents a novel method for the description of kinematic chains, namely the canonical description of kinematic chains including the synthetic degree-sequences and the canonical adjacency matrices sets of kinematic chains. The most important characteristic of this new description method is its uniqueness. Based on the new principle the isomorphism identification becomes easy and the structures of all kinds of kinematic chains can be stored in computer for the benefits of the realization of automation and intelligence of machine design.

  8. The Maiden Voyage of a Kinematics Robot

    Science.gov (United States)

    Greenwolfe, Matthew L.

    2015-04-01

    In a Montessori preschool classroom, students work independently on tasks that absorb their attention in part because the apparatus are carefully designed to make mistakes directly observable and limit exploration to one aspect or dimension. Control of error inheres in the apparatus itself, so that teacher intervention can be minimal.1 Inspired by this example, I created a robotic kinematics apparatus that also shapes the inquiry experience. Students program the robot by drawing kinematic graphs on a computer and then observe its motion. Exploration is at once limited to constant velocity and constant acceleration motion, yet open to complex multi-segment examples difficult to achieve in the lab in other ways. The robot precisely and reliably produces the motion described by the students' graphs, so that the apparatus itself provides immediate visual feedback about whether their understanding is correct as they are free to explore within the hard-coded limits. In particular, the kinematic robot enables hands-on study of multi-segment constant velocity situations, which lays a far stronger foundation for the study of accelerated motion. When correction is anonymous—just between one group of lab partners and their robot—students using the kinematic robot tend to flow right back to work because they view the correction as an integral part of the inquiry learning process. By contrast, when correction occurs by the teacher and/or in public (e.g., returning a graded assignment or pointing out student misconceptions during class), students all too often treat the event as the endpoint to inquiry. Furthermore, quantitative evidence shows a large gain from pre-test to post-test scores using the Test of Understanding Graphs in Kinematics (TUG-K).

  9. Three-dimensional kinematics of hummingbird flight.

    Science.gov (United States)

    Tobalske, Bret W; Warrick, Douglas R; Clark, Christopher J; Powers, Donald R; Hedrick, Tyson L; Hyder, Gabriel A; Biewener, Andrew A

    2007-07-01

    Hummingbirds are specialized for hovering flight, and substantial research has explored this behavior. Forward flight is also important to hummingbirds, but the manner in which they perform forward flight is not well documented. Previous research suggests that hummingbirds increase flight velocity by simultaneously tilting their body angle and stroke-plane angle of the wings, without varying wingbeat frequency and upstroke: downstroke span ratio. We hypothesized that other wing kinematics besides stroke-plane angle would vary in hummingbirds. To test this, we used synchronized high-speed (500 Hz) video cameras and measured the three-dimensional wing and body kinematics of rufous hummingbirds (Selasphorus rufus, 3 g, N=5) as they flew at velocities of 0-12 m s(-1) in a wind tunnel. Consistent with earlier research, the angles of the body and the stroke plane changed with velocity, and the effect of velocity on wingbeat frequency was not significant. However, hummingbirds significantly altered other wing kinematics including chord angle, angle of attack, anatomical stroke-plane angle relative to their body, percent of wingbeat in downstroke, wingbeat amplitude, angular velocity of the wing, wingspan at mid-downstroke, and span ratio of the wingtips and wrists. This variation in bird-centered kinematics led to significant effects of flight velocity on the angle of attack of the wing and the area and angles of the global stroke planes during downstroke and upstroke. We provide new evidence that the paths of the wingtips and wrists change gradually but consistently with velocity, as in other bird species that possess pointed wings. Although hummingbirds flex their wings slightly at the wrist during upstroke, their average wingtip-span ratio of 93% revealed that they have kinematically ;rigid' wings compared with other avian species.

  10. Effects of social intention on movement kinematics in cooperative actions

    Directory of Open Access Journals (Sweden)

    Francois eQuesque

    2013-10-01

    Full Text Available Optimal control models of biological movements are used to account for those internal variables that constrain voluntary goal-directed actions. They however do not take into account external environmental constraints as those associated to social intention. We investigated here the effects of the social context on kinematic characteristics of sequential actions consisting in placing an object on an initial pad (preparatory action before reaching and grasping as fast as possible the object to move it to another location (main action. Reach-to-grasp actions were performed either in an isolated condition or in the presence of a partner (audience effect, located in the near or far space (effect of shared reachable space, and who could intervene on the object in a systematic fashion (effect of social intention effect or not (effect of social uncertainty. Results showed an absence of audience effect but nevertheless an influence of the social context both on the main and the preparatory actions. In particular, a localized effect of shared reachable space was observed on the main action, which was smoother when performed within the reachable space of the partner. Furthermore, a global effect of social uncertainty was observed on both actions with faster and jerkier movements. Finally, social intention affected the preparatory action with higher wrist displacements and slower movements when the object was placed for the partner rather than placed for self-use. Overall, these results demonstrate specific effects of action space, social uncertainty and social intention on the planning of reach-to-grasp actions, in particular on the preparatory action, which was performed with no specific execution constraint. These findings underline the importance of considering the social context in optimal models of action control for human-robot interactions, in particular when focusing on the implementation of motor parameters required to afford intuitive

  11. Kinematic Constraints on Evolutionary Scenarios for Blue Compact Dwarf Galaxies I. Neutral Gas Dynamics

    CERN Document Server

    Van Zee, L; Skillman, E D; Zee, Liese van; Salzer, John J.; Skillman, Evan D.

    2001-01-01

    We present the results of high spatial resolution HI synthesis observations of six blue compact dwarf (BCD) galaxies. Optically, the selected galaxies have smooth, symmetric isophotes, and thus are the most likely of the BCD class to fade into an object morphologically similar to a dwarf elliptical when the current starburst ends. The neutral gas in all six galaxies appears to be rotationally supported, however, indicating that true morphological transformation from a BCD to a dE will require significant loss of angular momentum. Based on the observed neutral gas dynamics of these and other BCDs, it is unlikely that present-day BCDs will evolve directly into dwarf ellipticals after a starburst phase. We discuss alternative evolutionary scenarios for BCDs and place them within the larger context of galaxy formation and evolution models.

  12. Collinear cluster tri-partition: Kinematics constraints and stability of collinearity

    Science.gov (United States)

    Holmvall, P.; Köster, U.; Heinz, A.; Nilsson, T.

    2017-01-01

    Background: A new mode of nuclear fission has been proposed by the FOBOS Collaboration, called collinear cluster tri-partition (CCT), and suggests that three heavy fission fragments can be emitted perfectly collinearly in low-energy fission. This claim is based on indirect observations via missing-energy events using the 2 v 2 E method. This proposed CCT seems to be an extraordinary new aspect of nuclear fission. It is surprising that CCT escaped observation for so long given the relatively high reported yield of roughly 0.5 % relative to binary fission. These claims call for an independent verification with a different experimental technique. Purpose: Verification experiments based on direct observation of CCT fragments with fission-fragment spectrometers require guidance with respect to the allowed kinetic-energy range, which we present in this paper. Furthermore, we discuss corresponding model calculations which, if CCT is found in such verification experiments, could indicate how the breakups proceed. Since CCT refers to collinear emission, we also study the intrinsic stability of collinearity. Methods: Three different decay models are used that together span the timescales of three-body fission. These models are used to calculate the possible kinetic-energy ranges of CCT fragments by varying fragment mass splits, excitation energies, neutron multiplicities, and scission-point configurations. Calculations are presented for the systems 235U(nth,f ) and 252Cf(s f ) , and the fission fragments previously reported for CCT; namely, isotopes of the elements Ni, Si, Ca, and Sn. In addition, we use semiclassical trajectory calculations with a Monte Carlo method to study the intrinsic stability of collinearity. Results: CCT has a high net Q value but, in a sequential decay, the intermediate steps are energetically and geometrically unfavorable or even forbidden. Moreover, perfect collinearity is extremely unstable, and broken by the slightest perturbation. Conclusions: According to our results, the central fragment would be very difficult to detect due to its low kinetic energy, raising the question of why other 2 v 2 E experiments could not detect a missing-mass signature corresponding to CCT. Considering the high kinetic energies of the outer fragments reported in our study, direct-observation experiments should be able to observe CCT. Furthermore, we find that a realization of CCT would require an unphysical fine tuning of the initial conditions. Finally, our stability calculations indicate that, due to the pronounced instability of the collinear configuration, a prolate scission configuration does not necessarily lead to collinear emission, nor does equatorial emission necessarily imply an oblate scission configuration. In conclusion, our results enable independent experimental verification and encourage further critical theoretical studies of CCT.

  13. Collective behaviour of self-propelling particles with conservative kinematic constraints

    NARCIS (Netherlands)

    Ratushna, Valeriya Igorivna

    2007-01-01

    In this thesis I considered the dynamics of self-propelling particles (SPP). Flocking of living organisms like birds, fishes, ants, bacteria etc. is an area where the theory of the collective behaviour of SPP can be applied. One can often see how these animals develop coherent motion, amazing the ob

  14. Upper Limb Assessment in Tetraplegia: Clinical, Functional and Kinematic Correlations

    Science.gov (United States)

    Cacho, Enio Walker Azevedo; de Oliveira, Roberta; Ortolan, Rodrigo L.; Varoto, Renato; Cliquet, Alberto

    2011-01-01

    The aim of this study was to correlate clinical and functional evaluations with kinematic variables of upper limp reach-to-grasp movement in patients with tetraplegia. Twenty chronic patients were selected to perform reach-to-grasp kinematic assessment using a target placed at a distance equal to the arm's length. Kinematic variables (hand peak…

  15. Unitary Gas Constraints on Nuclear Symmetry Energy

    CERN Document Server

    Kolomeitsev, Evgeni E; Ohnishi, Akira; Tews, Ingo

    2016-01-01

    We show the existence of a lower bound on the volume symmetry energy parameter $S_0$ from unitary gas considerations. We further demonstrate that values of $S_0$ above this minimum imply upper and lower bounds on the symmetry energy parameter $L$ describing its lowest-order density dependence. The bounds are found to be consistent with both recent calculations of the energies of pure neutron matter and constraints from nuclear experiments. These results are significant because many equations of state in active use for simulations of nuclear structure, heavy ion collisions, supernovae, neutron star mergers, and neutron star structure violate these constraints.

  16. Motor resonance facilitates movement execution: an ERP and kinematic study

    Directory of Open Access Journals (Sweden)

    Mathilde eMénoret

    2013-10-01

    Full Text Available Action observation, simulation and execution share neural mechanisms that allow for a common motor representation. It is known that when these overlapping mechanisms are simultaneously activated by action observation and execution, motor performance is influenced by observation and vice versa. To understand the neural dynamics underlying this influence and to measure how variations in brain activity impact the precise kinematics of motor behaviour, we coupled kinematics and electrophysiological recordings of participants while they performed and observed congruent or non-congruent actions or during action execution alone. We found that movement velocities and the trajectory deviations of the executed actions increased during the observation of congruent actions compared to the observation of non-congruent actions or action execution alone. This facilitation was also discernible in the motor-related potentials of the participants; the motor-related potentials were transiently more negative in the congruent condition around the onset of the executed movement, which occurred 300 ms after the onset of the observed movement. This facilitation seemed to depend not only on spatial congruency but also on the optimal temporal relationship of the observation and execution events.

  17. Investigation of kinematic features for dismount detection and tracking

    Science.gov (United States)

    Narayanaswami, Ranga; Tyurina, Anastasia; Diel, David; Mehra, Raman K.; Chinn, Janice M.

    2012-05-01

    With recent changes in threats and methods of warfighting and the use of unmanned aircrafts, ISR (Intelligence, Surveillance and Reconnaissance) activities have become critical to the military's efforts to maintain situational awareness and neutralize the enemy's activities. The identification and tracking of dismounts from surveillance video is an important step in this direction. Our approach combines advanced ultra fast registration techniques to identify moving objects with a classification algorithm based on both static and kinematic features of the objects. Our objective was to push the acceptable resolution beyond the capability of industry standard feature extraction methods such as SIFT (Scale Invariant Feature Transform) based features and inspired by it, SURF (Speeded-Up Robust Feature). Both of these methods utilize single frame images. We exploited the temporal component of the video signal to develop kinematic features. Of particular interest were the easily distinguishable frequencies characteristic of bipedal human versus quadrupedal animal motion. We examine limits of performance, frame rates and resolution required for human, animal and vehicles discrimination. A few seconds of video signal with the acceptable frame rate allow us to lower resolution requirements for individual frames as much as by a factor of five, which translates into the corresponding increase of the acceptable standoff distance between the sensor and the object of interest.

  18. Metallicity and kinematics of the bar in-situ

    CERN Document Server

    Babusiaux, C; Hill, V; Royer, F; Gomez, A; Arenou, F; Combes, F; Di Matteo, P; Gilmore, G; Haywood, M; Robin, A C; Rodriguez-Fernandez, N; Sartoretti, P; Schultheis, M

    2014-01-01

    Constraints on the Galactic bulge/bar structure and formation history from stellar kinematics and metallicities mainly come from relatively high-latitude fields (|b|>4) where a complex mix of stellar population is seen. We aim here to constrain the formation history of the Galactic bar by studying the radial velocity and metallicity distributions of stars in-situ (|b|<1). We observed red clump stars in four fields along the bar's major axis (l=10,6,-6 and b=0 plus a field at l=0,b=1) with low-resolution spectroscopy from VLT/FLAMES, observing around the CaII triplet. We developed robust methods for extracting radial velocity and metallicity estimates from these low signal-to-noise spectra. We derived distance probability distributions using Bayesian methods rigorously handling the extinction law. We present radial velocities and metallicity distributions, as well as radial velocity trends with distance. We observe an increase in the radial velocity dispersion near the Galactic plane. We detect the streamin...

  19. The Lyman alpha reference sample. VII. Spatially resolved Hα kinematics

    Science.gov (United States)

    Herenz, Edmund Christian; Gruyters, Pieter; Orlitova, Ivana; Hayes, Matthew; Östlin, Göran; Cannon, John M.; Roth, Martin M.; Bik, Arjan; Pardy, Stephen; Otí-Floranes, Héctor; Mas-Hesse, J. Miguel; Adamo, Angela; Atek, Hakim; Duval, Florent; Guaita, Lucia; Kunth, Daniel; Laursen, Peter; Melinder, Jens; Puschnig, Johannes; Rivera-Thorsen, Thøger E.; Schaerer, Daniel; Verhamme, Anne

    2016-03-01

    We present integral field spectroscopic observations with the Potsdam Multi-Aperture Spectrophotometer of all 14 galaxies in the z ~ 0.1 Lyman Alpha Reference Sample (LARS). We produce 2D line-of-sight velocity maps and velocity dispersion maps from the Balmer α (Hα) emission in our data cubes. These maps trace the spectral and spatial properties of the LARS galaxies' intrinsic Lyα radiation field. We show our kinematic maps that are spatially registered onto the Hubble Space Telescope Hα and Lyman α (Lyα) images. We can conjecture a causal connection between spatially resolved Hα kinematics and Lyα photometry for individual galaxies, however, no general trend can be established for the whole sample. Furthermore, we compute the intrinsic velocity dispersion σ0, the shearing velocity vshear, and the vshear/σ0 ratio from our kinematic maps. In general LARS galaxies are characterised by high intrinsic velocity dispersions (54 km s-1 median) and low shearing velocities (65 km s-1 median). The vshear/σ0 values range from 0.5 to 3.2 with an average of 1.5. It is noteworthy that five galaxies of the sample are dispersion-dominated systems with vshear/σ0 1. Our result indicates that turbulence in actively star-forming systems is causally connected to interstellar medium conditions that favour an escape of Lyα radiation. Based on observations collected at the Centro Astronómico Hispano Alemán (CAHA) at Calar Alto, operated jointly by the Max-Planck Institut für Astronomie and the Instituto de Astrofísica de Andalucía (CSIC).The reduced data cubes (FITS files) are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/587/A78

  20. System reliability analysis for kinematic performance of planar mechanisms

    Institute of Scientific and Technical Information of China (English)

    ZHANG YiMin; HUANG XianZhen; ZHANG XuFang; HE XiangDong; WEN BangChun

    2009-01-01

    Based on the reliability and mechanism kinematic accuracy theories, we propose a general methodology for system reliability analysis of kinematic performance of planar mechanisms. The loop closure equations are used to estimate the kinematic performance errors of planar mechanisms. Reliability and system reliability theories are introduced to develop the limit state functions (LSF) for failure of kinematic performance qualities. The statistical fourth moment method and the Edgeworth series technique are used on system reliability analysis for kinematic performance of planar mechanisms, which relax the restrictions of probability distribution of design variables. Finally, the practicality, efficiency and accuracy of the proposed method are demonstrated by numerical examples.

  1. Kinematics and trajectory synthesis of manipulation robots

    CERN Document Server

    Vukobratović, Miomir

    1986-01-01

    A few words about the series "Scientific Fundamentals of Robotics" should be said on the occasion of publication of the present monograph. This six-volume series has been conceived so as to allow the readers to master a contemporary approach to the construction and synthesis of con­ trol for manipulation ~obots. The authors' idea was to show how to use correct mathematical models of the dynamics of active spatial mecha­ nisms for dynamic analysis of robotic systems, optimal design of their mechanical parts based on the accepted criteria and imposed constraints, optimal choice of actuators, synthesis of dynamic control algorithms and their microcomputer implementation. In authors' oppinion this idea has been relatively successfully realized within the six-volume mono­ graphic series. Let us remind the readers of the books of this series. Volumes 1 and 2 are devoted to the dynamics and control algorithms of manipulation ro­ bots, respectively. They form the first part of the series which has a certain topic...

  2. The kinematics of crustal deformation in Java from GPS observations: Implications for fault slip partitioning

    Science.gov (United States)

    Koulali, A.; McClusky, S.; Susilo, S.; Leonard, Y.; Cummins, P.; Tregoning, P.; Meilano, I.; Efendi, J.; Wijanarto, A. B.

    2017-01-01

    Our understanding of seismic risk in Java has been focused primarily on the subduction zone, where the seismic records during the last century have shown the occurrence of a number of tsunami earthquakes. However, the potential of the existence of active crustal structures within the island of Java itself is less well known. Historical archives show the occurrence of several devastating earthquake ruptures north of the volcanic arc in west Java during the 18th and the 19th centuries, suggesting the existence of active faults that need to be identified in order to guide seismic hazard assessment. Here we use geodetic constraints from the Global Positioning System (GPS) to quantify the present day crustal deformation in Java. The GPS velocities reveal a homogeneous counterclockwise rotation of the Java Block independent of Sunda Block, consistent with a NE-SW convergence between the Australian Plate and southeast Asia. Continuous GPS observations show a time-dependent change in the linear rate of surface motion in west Java, which we interpret as an ongoing long-term post-seismic deformation following the 2006 Mw 7.7 Java earthquake. We use an elastic block model in combination with a viscoelastic model to correct for this post-seismic transient and derive the long-term inter-seismic velocity, which we interpret as a combination of tectonic block motions and crustal faults strain related deformation. There is a north-south gradient in the resulting velocity field with a decrease in the magnitude towards the North across the Kendeng Thrust in the east and the Baribis Thrust in the west. We suggest that the Baribis Thrust is active and accommodating a slow relative motion between Java and the Sunda Block at about 5 ± 0.2 mm /yr. We propose a kinematic model of convergence of the Australian Plate and the Sunda Block, involving a slip partitioning between the Java Trench and a left-lateral structure extending E-W along Java with most of the convergence being

  3. The Incidence, Geometry, and Kinematics of Extraplanar Gas in MaNGA Galaxies

    Science.gov (United States)

    Diamond-Stanic, Aleksandar M.; MaNGA Team

    2016-01-01

    The efficiency of star formation in galaxies is regulated by the cycle of accretion and feedback processes in the circumgalactic medium. The geometry, kinematics, and multi-phase structure of circumgalactic gas are not well predicted by numerical simulations, so there is motivation to characterize these properties empirically by observing ionized gas around galaxies in both emission and absorption. Absorption-line studies are quite sensitive to diffuse gas at low column densities, but they are limited in scope because they require bright background sources, which are rare and offer pencil-beam probes of gas properties for individual galaxies. A complementary approach is to use optical emission lines to study extraplanar diffuse ionized gas, which can trace the spatial extent and kinematics of outflowing and inflowing gas. Using the unique dataset of spatially resolved spectroscopy from MaNGA (Mapping Nearby Galaxies at Apache Point Observatory), we are developing techniques to identify galaxies with extraplanar gas on the basis of optical emission lines that extend above and below the plane of disk galaxies. Our initial results suggest that extraplanar gas is quite common among galaxies in the MaNGA sample, particularly among star-forming galaxies with inclination angles greater than 45 degrees, for which it is more straightforward to separate extraplanar gas from emission associated with the disk. These results on the incidence, geometry, and kinematics of extraplanar gas as a function of global galaxy properties provide important constraints on models of accretion and feedback in the circumgalactic medium.

  4. The influence of body posture on the kinematics of prehension in humans and gorillas (Gorilla gorilla).

    Science.gov (United States)

    Reghem, E; Chèze, L; Coppens, Y; Pouydebat, E

    2014-03-01

    Much of our current understanding of human prehension in a comparative context is based on macaque models in a sitting, constrained body posture. In a previous study, we clearly showed differences in the amplitude of the forelimb joints between five primate species (lemur, capuchin, chimpanzee, gorilla and human) during unconstrained grasping where the animals were free to choose their body posture. One of our interrogations was to know if these differences could be due to the body posture. To address this question, this study compares humans with new data for gorillas during an unconstrained food prehension task in two body postures, a sitting and a quadrupedal one. The objective is to determine the behavioral and kinematic strategies (amplitudes and patterns of evolution of the articular angles) as well as differences and invariants of trunk and forelimb motions between species. The subjects were recorded by five cameras, and landmarks were digitized frame by frame to reconstruct 3D movement. Our results show that (1) despite significant influences of body postures on ranges of motion in gorillas and humans, species preserve their specific forelimb joint and trunk contribution; (2) body posture has a limited effect on the basic pattern of wrist velocity. Our study indicates that different primate species have specific kinematic features of limb coordination during prehension, which dose not alter with changes in posture. Therefore, across varying species, it is possible to compare limb kinematics irrespective of postural constraints and unconstrained condition need to be explored in other primates to understand the evolution of primate prehension.

  5. Asteroseismic constraints for Gaia

    CERN Document Server

    Creevey, O L

    2012-01-01

    Distances from the Gaia mission will no doubt improve our understanding of stellar physics by providing an excellent constraint on the luminosity of the star. However, it is also clear that high precision stellar properties from, for example, asteroseismology, will also provide a needed input constraint in order to calibrate the methods that Gaia will use, e.g. stellar models or GSP_phot. For solar-like stars (F, G, K IV/V), asteroseismic data delivers at the least two very important quantities: (1) the average large frequency separation and (2) the frequency corresponding to the maximum of the modulated-amplitude spectrum nu_max. Both of these quantities are related directly to stellar parameters (radius and mass) and in particular their combination (gravity and density). We show how the precision in , nu_max, and atmospheric parameters T_eff and [Fe/H] affect the determination of gravity (log g) for a sample of well-known stars. We find that log g can be determined within less than 0.02 dex accuracy for ou...

  6. Design with Nonlinear Constraints

    KAUST Repository

    Tang, Chengcheng

    2015-12-10

    Most modern industrial and architectural designs need to satisfy the requirements of their targeted performance and respect the limitations of available fabrication technologies. At the same time, they should reflect the artistic considerations and personal taste of the designers, which cannot be simply formulated as optimization goals with single best solutions. This thesis aims at a general, flexible yet e cient computational framework for interactive creation, exploration and discovery of serviceable, constructible, and stylish designs. By formulating nonlinear engineering considerations as linear or quadratic expressions by introducing auxiliary variables, the constrained space could be e ciently accessed by the proposed algorithm Guided Projection, with the guidance of aesthetic formulations. The approach is introduced through applications in different scenarios, its effectiveness is demonstrated by examples that were difficult or even impossible to be computationally designed before. The first application is the design of meshes under both geometric and static constraints, including self-supporting polyhedral meshes that are not height fields. Then, with a formulation bridging mesh based and spline based representations, the application is extended to developable surfaces including origami with curved creases. Finally, general approaches to extend hard constraints and soft energies are discussed, followed by a concluding remark outlooking possible future studies.

  7. Electron beam gun with kinematic coupling for high power RF vacuum devices

    Energy Technology Data Exchange (ETDEWEB)

    Borchard, Philipp

    2016-11-22

    An electron beam gun for a high power RF vacuum device has components joined by a fixed kinematic coupling to provide both precise alignment and high voltage electrical insulation of the components. The kinematic coupling has high strength ceramic elements directly bonded to one or more non-ductile rigid metal components using a high temperature active metal brazing alloy. The ceramic elements have a convex surface that mates with concave grooves in another one of the components. The kinematic coupling, for example, may join a cathode assembly and/or a beam shaping focus electrode to a gun stem, which is preferably composed of ceramic. The electron beam gun may be part of a high power RF vacuum device such as, for example, a gyrotron, klystron, or magnetron.

  8. Motion analysis of the shoulder in adults: kinematics and electromyography for the clinical practice.

    Science.gov (United States)

    Parel, Ilaria; Jaspers, Ellen; DE Baets, Liesbet; Amoresano, Amedeo; Cutti, Andrea G

    2016-08-01

    In this paper, the principal aspects of kinematic and electromyographic (EMG) analysis of the shoulder and their potential for the every-day clinical practice are described. The text reports a brief description of standard recommendations for movement assessment, an overview of the main quantitative motion analysis protocols and a description of the most commonly investigated scapulothoracic muscles. To assess the possibility of using these protocols for clinical applications, reliability and repeatability of kinematic and EMG measures were investigated and reference data for scapulohumeral joint kinematics were provided. The last part of the manuscript reports the integration of the quantitative analysis of scapula dyskinesis within the widely accepted Constant-Murley clinical score. In addition, examples of assessment of muscles activity and recruitment patterns are discussed since they are crucial for the clinical evaluation of common shoulder pathologies.

  9. Neural Network-Based Control of Networked Trilateral Teleoperation With Geometrically Unknown Constraints.

    Science.gov (United States)

    Li, Zhijun; Xia, Yuanqing; Wang, Dehong; Zhai, Di-Hua; Su, Chun-Yi; Zhao, Xingang

    2016-05-01

    Most studies on bilateral teleoperation assume known system kinematics and only consider dynamical uncertainties. However, many practical applications involve tasks with both kinematics and dynamics uncertainties. In this paper, trilateral teleoperation systems with dual-master-single-slave framework are investigated, where a single robotic manipulator constrained by an unknown geometrical environment is controlled by dual masters. The network delay in the teleoperation system is modeled as Markov chain-based stochastic delay, then asymmetric stochastic time-varying delays, kinematics and dynamics uncertainties are all considered in the force-motion control design. First, a unified dynamical model is introduced by incorporating unknown environmental constraints. Then, by exact identification of constraint Jacobian matrix, adaptive neural network approximation method is employed, and the motion/force synchronization with time delays are achieved without persistency of excitation condition. The neural networks and parameter adaptive mechanism are combined to deal with the system uncertainties and unknown kinematics. It is shown that the system is stable with the strict linear matrix inequality-based controllers. Finally, the extensive simulation experiment studies are provided to demonstrate the performance of the proposed approach.

  10. Analysis of Active Force and Constraint Force of Parallel Manipulator Based on Virtual Work Theory%基于虚功原理的并联机构驱动力和约束力分析

    Institute of Scientific and Technical Information of China (English)

    叶勇

    2012-01-01

    Based on the virtual work theory, the active and constraint forces of each limb of the parallel manipulator are solved. Taking the 2SPS + 2UPU spatial parallel manipulator as research object, a simulation mechanism of the parallel manipulator with Euler angles was created firstly. Then the force/torque simulation mechanisms were created. When modifying the driving dimension, the configuration of the simulation mechanisms were varied correspondingly, and the active and constraint forces were solved automatically and visualized dynamically. The results show that the CAD variation geometry is fairly quick and straightforward, and is also advantageous from viewpoint of accuracy and reliability.%以虚功原理为基础,利用CAD变量几何法,求解空间并联机构各分支的驱动力和约束力.以一种空间2SPS+ 2UPU并联机构为例,首先构造含有欧拉角的该机构的模拟机构,在此基础上进一步构造F/T(力/力矩)模拟机构,得到其驱动力和约束力解.当改变驱动参数时,F/T(力/力矩)模拟机构随之变化,驱动力和约束力自动求解和动态显示.结果表明CAD变量几何法不仅快速直观,而且准确可靠.

  11. Kinematical uniqueness of homogeneous isotropic LQC

    Science.gov (United States)

    Engle, Jonathan; Hanusch, Maximilian

    2017-01-01

    In a paper by Ashtekar and Campiglia, invariance under volume preserving residual diffeomorphisms has been used to single out the standard representation of the reduced holonomy-flux algebra in homogeneous loop quantum cosmology (LQC). In this paper, we use invariance under all residual diffeomorphisms to single out the standard kinematical Hilbert space of homogeneous isotropic LQC for both the standard configuration space {{{R}}\\text{Bohr}} , as well as for the Fleischhack one {R}\\sqcup {{{R}}\\text{Bohr}} . We first determine the scale invariant Radon measures on these spaces, and then show that the Haar measure on {{{R}}\\text{Bohr}} is the only such measure for which the momentum operator is hermitian w.r.t. the corresponding inner product. In particular, the measure is forced to be identically zero on {R} in the Fleischhack case, so that for both approaches, the standard kinematical LQC-Hilbert space is singled out.

  12. Quantum gravity kinematics from extended TQFTs

    CERN Document Server

    Dittrich, Bianca

    2016-01-01

    We show how extended topological quantum field theories (TQFTs) can be used to obtain a kinematical setup for quantum gravity, i.e. a kinematical Hilbert space together with a representation of the observable algebra including operators of quantum geometry. In particular, we consider the holonomy-flux algebra of (2+1)-dimensional Euclidean loop quantum gravity, and construct a new representation of this algebra that incorporates a positive cosmological constant. The vacuum state underlying our representation is defined by the Turaev-Viro TQFT. We therefore construct here a generalization, or more precisely a quantum deformation at root of unity, of the previously-introduced SU(2) BF representation. The extended Turaev-Viro TQFT provides a description of the excitations on top of the vacuum, which are essential to allow for a representation of the holonomies and fluxes. These excitations agree with the ones induced by massive and spinning particles, and therefore the framework presented here allows automatical...

  13. Kinematics of the symbiotic system R Aqr

    Science.gov (United States)

    Navarro, S.; Corral, L. J.; Steffen, W.

    2014-04-01

    We present the results of the kinematical analysis of the symbiotic system R Aqr. We obtained high dispersion spectra with the MES spectrograph at the 2.1 m telescope of San Pedro Mártir (MEZCAL). The used filter were Ha + [NII], (λc = 6575Å, Δλ = 90Å). We analyse the [NII] λλ6583 line. When the observations are compared with previous ones by Solf (1992) we detected an important change in the projected velocities of the observed knots, supporting the idea of a precessing jet. We are working also in a 3-D kinematic model for the object using the measured velocities and the state of the model is presented.

  14. The kinematic component of the cosmological redshift

    CERN Document Server

    Chodorowski, Michał

    2009-01-01

    It is widely believed that the cosmological redshift is not a Doppler shift. However, Bunn & Hogg have recently pointed out that to settle properly this problem, one has to transport parallelly the velocity four-vector of a distant galaxy to the observer's position. Performing such a transport along the null geodesic of photons arriving from the galaxy, they found that the cosmological redshift is purely kinematic. Here we argue that one should rather transport the velocity four-vector along the geodesic connecting the points of intersection of the world-lines of the galaxy and the observer with the hypersurface of constant COSMIC TIME. We find that the resulting relation between the transported velocity and the redshift of arriving photons is NOT given by a relativistic Doppler formula. Instead, for small redshifts it coincides with the well known non-relativistic decomposition of the redshift into a Doppler (kinematic) component and a gravitational component. We perform such a decomposition for arbitrar...

  15. Kinematic measurements using an infrared sensor

    CERN Document Server

    Marinho, F

    2016-01-01

    The use of an infrared sensor as a new alternative to measure position as a function of time in kinematic experiments was investigated using a microcontroller as data acquisition and control device. These are versatile sensors that offer advantages over the typical ultrasound devices. The setup described in this paper enables students to develop their own experiments promoting opportunities for learning physical concepts such as the different types of forces that can act on a body (gravitational, elastic, drag, etc.) and the resulting types of movements with good sensitivity within the $\\rm 4-30~cm$ range. As proof of concept we also present the application of a prototype designed to record the kinematics of mass-spring systems.

  16. Kinematics of horizontal and vertical caterpillar crawling.

    Science.gov (United States)

    van Griethuijsen, Linnea I; Trimmer, Barry A

    2009-05-01

    Unlike horizontal crawling, vertical crawling involves two counteracting forces: torque rotating the body around its center of mass and gravity resisting forward movement. The influence of these forces on kinematics has been examined in the soft-bodied larval stage of Manduca sexta. We found that crawling and climbing are accomplished using the same movements, with both segment timing and proleg lift indistinguishable in horizontal and vertical locomotion. Minor differences were detected in stride length and in the delay between crawls, which led to a lower crawling speed in the vertical orientation. Although these differences were statistically significant, they were much smaller than the variation in kinematic parameters between animals. The ability of Manduca to crawl and climb using the same movements is best explained by Manduca's relatively small size, slow speed and strong, controlled, passive grip made possible by its proleg/crochets.

  17. Plasma electron-hole kinematics: momentum conservation

    CERN Document Server

    Hutchinson, I H

    2016-01-01

    We analyse the kinematic properties of a plasma electron hole: a non-linear self-sustained localized positive electric potential perturbation, trapping electrons, that behaves as a coherent entity. When a hole accelerates or grows in depth, ion and electron plasma momentum is changed both within the hole and outside it, by an energization process we call jetting. We present a comprehensive analytic calculation of the momentum changes of an isolated general one-dimensional hole. The conservation of the total momentum gives the hole's kinematics, determining its velocity evolution. Our results explain many features of the behavior of hole speed observed in numerical simulations, including self-acceleration at formation, and hole pushing and trapping by ion streams.

  18. A Kinematical Calibration of the Galactocentric Distance

    Institute of Scientific and Technical Information of China (English)

    Ming Shen; Zi Zhu

    2007-01-01

    We present a new determination of the Galactocentric distance by a pure kinematical model. Two subgroups of components from the Galactic thin disk, the O-B5 stars and the Galactic open clusters, were selected for our analysis. On the basis of kinematical data of around 1200 O-B5 stars, we obtained an estimated value of R0=8.25±0.79 kpc, while a similar evaluation from 270 Galactic open clusters gives R0=7.95±0.62 kpc. Considering the scatter of R0 given by individual investigators with different methods, our present determinations agree well with the best value proposed by Reid.

  19. Surface growth kinematics via local curve evolution

    KAUST Repository

    Moulton, Derek E.

    2012-11-18

    A mathematical framework is developed to model the kinematics of surface growth for objects that can be generated by evolving a curve in space, such as seashells and horns. Growth is dictated by a growth velocity vector field defined at every point on a generating curve. A local orthonormal basis is attached to each point of the generating curve and the velocity field is given in terms of the local coordinate directions, leading to a fully local and elegant mathematical structure. Several examples of increasing complexity are provided, and we demonstrate how biologically relevant structures such as logarithmic shells and horns emerge as analytical solutions of the kinematics equations with a small number of parameters that can be linked to the underlying growth process. Direct access to cell tracks and local orientation enables for connections to be made to the underlying growth process. © 2012 Springer-Verlag Berlin Heidelberg.

  20. Kinematic measurements using an infrared sensor

    Science.gov (United States)

    Marinho, F.; Paulucci, L.

    2016-03-01

    The use of an infrared sensor as a new alternative to measure position as a function of time in kinematic experiments was investigated using a microcontroller as the data acquisition and control device. These are versatile sensors that offer advantages over typical ultrasound devices. The setup described in this paper enables students to develop their own experiments, promoting opportunities for learning physical concepts such as the different types of forces that can act on a body (gravitational, elastic, drag, etc) and the resulting types of movements with good sensitivity within the 4-30 cm range. As a proof of concept we also present the application of a prototype designed to record the kinematics of mass-spring systems.

  1. Foot kinematics and kinetics during adolescent gait.

    Science.gov (United States)

    MacWilliams, Bruce A; Cowley, Matthew; Nicholson, Diane E

    2003-06-01

    Gait analysis models typically analyze the ankle joint complex and treat the foot as a rigid segment. Such models are inadequate for clinical decision making for patients with foot impairments. While previous multisegment foot models have been presented, no comprehensive kinematic and kinetic databases for normal gait exist. This study provides normative foot joint angles, moments and powers during adolescent gait. Eighteen subjects were evaluated using 19 retroreflective markers, six cameras, a pressure platform and a force plate. A nine-segment model determined 3D angles, 3D moments, and powers in eight joints or joint complexes. A complete sets of sagittal, coronal and frontal plane results are presented. Results indicate that single link models of the foot significantly overestimate ankle joint powers during gait. Understanding normal joint kinematics and kinetics during gait will provide a baseline for documenting impairments in patients with foot disorders.

  2. 6th International Workshop on Computational Kinematics

    CERN Document Server

    Gracia, Alba

    2014-01-01

    Computational kinematics is an enthralling area of science with a rich spectrum of problems at the junction of mechanics, robotics, computer science, mathematics, and computer graphics. The covered topics include design and optimization of cable-driven robots, analysis of parallel manipulators, motion planning, numerical methods for mechanism calibration and optimization, geometric approaches to mechanism analysis and design, synthesis of mechanisms, kinematical issues in biomechanics, construction of novel mechanical devices, as well as detection and treatment of singularities. The results should be of interest for practicing and research engineers as well as Ph.D. students from the fields of mechanical and electrical engineering, computer science, and computer graphics. Indexed in Conference Proceedings Citation Index- Science (CPCI-S).

  3. The kinematic advantage of electric cars

    Science.gov (United States)

    Meyn, Jan-Peter

    2015-11-01

    Acceleration of a common car with with a turbocharged diesel engine is compared to the same type with an electric motor in terms of kinematics. Starting from a state of rest, the electric car reaches a distant spot earlier than the diesel car, even though the latter has a better specification for engine power and average acceleration from 0 to 100 km h-1. A three phase model of acceleration as a function of time fits the data of the electric car accurately. The first phase is a quadratic growth of acceleration in time. It is shown that the tenfold higher coefficient for the first phase accounts for most of the kinematic advantage of the electric car.

  4. Kinematical uniqueness of homogeneous isotropic LQC

    CERN Document Server

    Engle, Jonathan

    2016-01-01

    In a paper by Ashtekar and Campiglia, invariance under volume preserving residual diffeomorphisms has been used to single out the standard representation of the reduced holonomy-flux algebra in homogeneous loop quantum cosmology (LQC). In this paper, we use invariance under all residual diffeomorphisms to single out the standard kinematical Hilbert space of homogeneous isotropic LQC for both the standard configuration space $\\mathbb{R}_{\\mathrm{Bohr}}$, as well as for the Fleischhack one $\\mathbb{R} \\sqcup \\mathbb{R}_{\\mathrm{Bohr}}$. We first determine the scale invariant Radon measures on these spaces, and then show that the Haar measure on $\\mathbb{R}_{\\mathrm{Bohr}}$ is the only such measure for which the momentum operator is hermitian w.r.t. the corresponding inner product. In particular, the measure is forced to be identically zero on $\\mathbb{R}$ in the Fleischhack case, so that for both approaches, the standard kinematical LQC-Hilbert space is singled out.

  5. Kinematic analysis of head, trunk, and pelvis movement when people early after stroke reach sideways.

    NARCIS (Netherlands)

    Verheyden, G.; Duijnhoven, H.J.R. van; Burnett, M.; Littlewood, J.; Kunkel, D.; Ashburn, A.M.

    2011-01-01

    BACKGROUND: Sideways reaching with the unaffected arm while seated is a component of everyday activities and can be a challenging task early after stroke. Kinematic analysis of a lateral reach task may provide potential rehabilitation strategies. OBJECTIVE: The authors examined the difference betwee

  6. The Alpine evolution of Thessaly (NW Greece) and Late Tertiary Aegean kinematics

    NARCIS (Netherlands)

    Walcott, C.R.

    1998-01-01

    The Aegean region is one ofthe most studied regions currently undergoing post-orogenic extension. Numerous kinematic and dynamic models have been proposed to account for its active tectonics. Most recent studies have demonstrated that, since the onset ofextension in the early Miocene, there has been

  7. Kinematic Diversity in Rorqual Whale Feeding Mechanisms.

    Science.gov (United States)

    Cade, David E; Friedlaender, Ari S; Calambokidis, John; Goldbogen, Jeremy A

    2016-10-10

    Rorqual whales exhibit an extreme lunge filter-feeding strategy characterized by acceleration to high speed and engulfment of a large volume of prey-laden water [1-4]. Although tagging studies have quantified the kinematics of lunge feeding, the timing of engulfment relative to body acceleration has been modeled conflictingly because it could never be directly measured [5-7]. The temporal coordination of these processes has a major impact on the hydrodynamics and energetics of this high-cost feeding strategy [5-9]. If engulfment and body acceleration are temporally distinct, the overall cost of this dynamic feeding event would be minimized. However, greater temporal overlap of these two phases would theoretically result in higher drag and greater energetic costs. To address this discrepancy, we used animal-borne synchronized video and 3D movement sensors to quantify the kinematics of both the skull and body during feeding events. Krill-feeding blue and humpback whales exhibited temporally distinct acceleration and engulfment phases, with humpback whales reaching maximum gape earlier than blue whales. In these whales, engulfment coincided largely with body deceleration; however, humpback whales pursuing more agile fish demonstrated highly variable coordination of skull and body kinematics in the context of complex prey-herding techniques. These data suggest that rorquals modulate the coordination of acceleration and engulfment to optimize foraging efficiency by minimizing locomotor costs and maximizing prey capture. Moreover, this newfound kinematic diversity observed among rorquals indicates that the energetic efficiency of foraging is driven both by the whale's engulfment capacity and the comparative locomotor capabilities of predator and prey. VIDEO ABSTRACT.

  8. Kinematic dynamo induced by helical waves

    OpenAIRE

    Wei, Xing

    2014-01-01

    We investigate numerically the kinematic dynamo induced by the superposition of two helical waves in a periodic box as a simplified model to understand the dynamo action in astronomical bodies. The effects of magnetic Reynolds number, wavenumber and wave frequency on the dynamo action are studied. It is found that this helical-wave dynamo is a slow dynamo. There exists an optimal wavenumber for the dynamo growth rate. A lower wave frequency facilitates the dynamo action and the oscillations o...

  9. Treatment of photon radiation in kinematics fits at future e{sup +}e{sup -} colliders

    Energy Technology Data Exchange (ETDEWEB)

    Beckmann, M.; List, J. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); List, B. [Hamburg Univ. (Germany). Inst. fuer Experimentalphysik

    2010-05-15

    Kinematic fitting, where constraints such as energy and momentum conservation are imposed on measured four-vectors of jets and leptons, is an important tool to improve the resolution in high-energy physics experiments. At future e{sup +}e{sup -} colliders, photon radiation parallel to the beam carrying away large amounts of energy and momentum will become a challenge for kinematic fitting. A photon with longitudinal momentum p{sub z,{gamma}} ({eta}) is introduced, which is parametrized such that {eta} follows a normal distribution. In the fit, {eta} is treated as having a measured value of zero, which corresponds to p{sub z,{gamma}}, = 0. As a result, fits with constraints on energy and momentum conservation converge well even in the presence of a highly energetic photon, while the resolution of fits without such a photon is retained. A fully simulated and reconstructed e{sup +}e{sup -}{yields}q anti qq anti q event sample at {radical}(s)=500 GeV is used to investigate the performance of this method under realistic conditions, as expected at the International Linear Collider. (orig.)

  10. Treatment of Photon Radiation in Kinematic Fits at Future e+ e- Colliders

    CERN Document Server

    Beckmann, Moritz; List, Jenny

    2010-01-01

    Kinematic fitting, where constraints such as energy and momentum conservation are imposed on measured four-vectors of jets and leptons, is an important tool to improve the resolution in high-energy physics experiments. At future e+ e- colliders, photon radiation parallel to the beam carrying away large amounts of energy and momentum will become a challenge for kinematic fitting. A photon with longitudinal momentum p_z^\\gamma (\\eta) is introduced, which is parametrized such that \\eta ~follows a normal distribution. In the fit, \\eta ~is treated as having a measured value of zero, which corresponds to p_z^\\gamma (\\eta)=0. As a result, fits with constraints on energy and momentum conservation converge well even in the presence of a highly energetic photon, while the resolution of fits without such a photon is retained. A fully simulated and reconstructed e+ e- -> qqqq event sample at \\sqrt{s}=500 GeV is used to investigate the performance of this method under realistic conditions, as expected at the International...

  11. Kinematic gait analyses in healthy Golden Retrievers

    Directory of Open Access Journals (Sweden)

    Gabriela C.A. Silva

    2014-12-01

    Full Text Available Kinematic analysis relates to the relative movement between rigid bodies and finds application in gait analysis and other body movements, interpretation of their data when there is change, determines the choice of treatment to be instituted. The objective of this study was to standardize the march of Dog Golden Retriever Healthy to assist in the diagnosis and treatment of musculoskeletal disorders. We used a kinematic analysis system to analyse the gait of seven dogs Golden Retriever, female, aged between 2 and 4 years, weighing 21.5 to 28 kg, clinically normal. Flexion and extension were described for shoulder, elbow, carpal, hip, femorotibialis and tarsal joints. The gait was characterized lateral and had accepted hypothesis of normality for all variables, except for the stance of hip and elbow, considering a confidence level of 95%, significance level α = 0.05. Variations have been attributed to displacement of the stripes during movement and the duplicated number of reviews. The kinematic analysis proved to be a consistent method of evaluation of the movement during canine gait and the data can be used in the diagnosis and evaluation of canine gait in comparison to other studies and treatment of dogs with musculoskeletal disorders.

  12. Scapula Kinematics of Youth Baseball Players.

    Science.gov (United States)

    Oliver, Gretchen; Weimar, Wendi

    2015-12-22

    Literature has revealed the importance of quantifying resting scapular posture in overhead athletes as well as quantifying scapular kinematics during dynamic movement. Prior to this project much of the attention in throwing research had been focused on the position of the humerus without description of the positioning of the scapula. Therefore, it was the purpose of this study to present scapular kinematics during pitching in youth baseball players. Twenty-five youth baseball players (age 11.3 + 1.0 years; body height 152.4 + 9.0 cm; body mass 47.5 + 11.3 kg), with no history of injury, participated in the study. Scapular kinematics at the events of maximum humeral external rotation (MER) and maximum humeral internal rotation (MIR) during the pitching motion were assessed three-dimensionally while pitching fastballs for strikes. Results revealed that at the event of MER, the scapula was in a position of retraction, upward rotation and a posterior tilt. While at the event of MIR, the scapula was protracted, upward rotated and tilted anteriorly.

  13. Scapula Kinematics of Youth Baseball Players

    Directory of Open Access Journals (Sweden)

    Oliver Gretchen

    2015-12-01

    Full Text Available Literature has revealed the importance of quantifying resting scapular posture in overhead athletes as well as quantifying scapular kinematics during dynamic movement. Prior to this project much of the attention in throwing research had been focused on the position of the humerus without description of the positioning of the scapula. Therefore, it was the purpose of this study to present scapular kinematics during pitching in youth baseball players. Twenty-five youth baseball players (age 11.3 + 1.0 years; body height 152.4 + 9.0 cm; body mass 47.5 + 11.3 kg, with no history of injury, participated in the study. Scapular kinematics at the events of maximum humeral external rotation (MER and maximum humeral internal rotation (MIR during the pitching motion were assessed three-dimensionally while pitching fastballs for strikes. Results revealed that at the event of MER, the scapula was in a position of retraction, upward rotation and a posterior tilt. While at the event of MIR, the scapula was protracted, upward rotated and tilted anteriorly.

  14. Kinematics of Straight Right Punch in Boxing

    Directory of Open Access Journals (Sweden)

    Mahdi Cheraghi

    2014-07-01

    Full Text Available The purpose of this study was to describe biomechanical parameters of head, upper and lower body extremities during a straight right punch throw related to performance and injury mechanism. Subjects were eight elite right-handed male (age 20.4 ± 2.1yrs; height 177.4 ± 8.5 cm; mass 70.4 ± 16.8 kg amateur boxers. 3D motion analysis was used to assess the kinematics of the right side extremities and head. Ensemble averaging of time normalized kinematic parameters was used to have better visual inspection. Results showed a similar pattern between subjects with some considerable variation in some parameters that pointed out to individualized pattern in elite boxers. Investigation of lower body joints kinematics explained boxers throw punch using leg drive. Stretch-shortening cycle detected in the technique implies potential for performance enhancing using plyometrics. Head velocity measured in anterior-posterior and medial-lateral direction would intensify potential head injuries.

  15. Dynamic and kinematic strategies for head movement control

    Science.gov (United States)

    Peterson, B. W.; Choi, H.; Hain, T.; Keshner, E.; Peng, G. C.

    2001-01-01

    This paper describes our analysis of the complex head-neck system using a combination of experimental and modeling approaches. Dynamical analysis of head movements and EMG activation elicited by perturbation of trunk position has examined functional contributions of biomechanically and neurally generated forces in lumped systems with greatly simplified kinematics. This has revealed that visual and voluntary control of neck muscles and the dynamic and static vestibulocollic and cervicocollic reflexes preferentially govern head-neck system state in different frequency domains. It also documents redundant control, which allows the system to compensate for lesions and creates a potential for substantial variability within and between subjects. Kinematic studies have indicated the existence of reciprocal and co-contraction strategies for voluntary force generation, of a vestibulocollic strategy for stabilizing the head during body perturbations and of at least two strategies for voluntary head tracking. Each strategy appears to be executed by a specific muscle synergy that is presumably optimized to efficiently meet the demands of the task.

  16. Computational tool for comparison of kinematic mechanisms and commonly used kinematic models

    Energy Technology Data Exchange (ETDEWEB)

    Hollerbach, K.; Hollister, A.M.; Van Vorhis, R.L.

    1997-03-01

    Accurate, reliable, and reproducible methods to measure the movements of human joints have been elusive. Currently, three-dimensional recording methods are used to track the motion of one segment relative to another as the joint moves. Six parameters describe the moving segment`s location and orientation relative to the reference segment: three translations (x, y, and z) and three rotations (yaw, pitch and roll) in the reference frame. The raw data can be difficult to interpret. For this reason, several methods have been developed to measure the motion of human joints and to describe the resulting data. For example, instant helical axes or screw deviation axes (Kinzell et al., 1972), the Joint Coordinate System of Grood and Suntay (1983), and the Euler angle method have been used to describe the movements of bones relative to each other. None of these methods takes into account the physical kinematic mechanism producing the joint motion. More recently, Lupichuk (1995) has developed an algorithm to find, for an arbitrary revolute, the axis` position and orientation in three- dimensional space. Each of these methods has advantages and disadvantages in analyzing joint kinematics. The authors have developed software to provide a means of comparing these methods for arbitrary, single degree of freedom, kinematic mechanisms. Our objective is to demonstrate the software and to show how it can be used to compare the results from the different kinematic models as they are applied to specific kinematic mechanisms.

  17. Rewriting Constraint Models with Metamodels

    CERN Document Server

    Chenouard, Raphael; Soto, Ricardo

    2010-01-01

    An important challenge in constraint programming is to rewrite constraint models into executable programs calculat- ing the solutions. This phase of constraint processing may require translations between constraint programming lan- guages, transformations of constraint representations, model optimizations, and tuning of solving strategies. In this paper, we introduce a pivot metamodel describing the common fea- tures of constraint models including different kinds of con- straints, statements like conditionals and loops, and other first-class elements like object classes and predicates. This metamodel is general enough to cope with the constructions of many languages, from object-oriented modeling languages to logic languages, but it is independent from them. The rewriting operations manipulate metamodel instances apart from languages. As a consequence, the rewriting operations apply whatever languages are selected and they are able to manage model semantic information. A bridge is created between the metamode...

  18. Constraint Propagation as Information Maximization

    CERN Document Server

    Abdallah, A Nait

    2012-01-01

    Dana Scott used the partial order among partial functions for his mathematical model of recursively defined functions. He interpreted the partial order as one of information content. In this paper we elaborate on Scott's suggestion of regarding computation as a process of information maximization by applying it to the solution of constraint satisfaction problems. Here the method of constraint propagation can be interpreted as decreasing uncertainty about the solution -- that is, as gain in information about the solution. As illustrative example we choose numerical constraint satisfaction problems to be solved by interval constraints. To facilitate this approach to constraint solving we formulate constraint satisfaction problems as formulas in predicate logic. This necessitates extending the usual semantics for predicate logic so that meaning is assigned not only to sentences but also to formulas with free variables.

  19. Constraints On Cosmic Dynamics

    CERN Document Server

    Mbonye, M R

    2003-01-01

    Observationally, the universe appears virtually critical. Yet, there is no simple explanation for this state. In this article we advance and explore the premise that the dynamics of the universe always seeks equilibrium conditions. Vacuum-induced cosmic accelerations lead to creation of matter-energy modes at the expense of vacuum energy. Because they gravitate, such modes constitute inertia against cosmic acceleration. On the other extreme, the would-be ultimate phase of local gravitational collapse is checked by a phase transition in the collapsing matter fields leading to a de Sitter-like fluid deep inside the black hole horizon, and at the expense of the collapsing matter fields. As a result, the universe succumbs to neither vacuum-induced run-away accelerations nor to gravitationally induced spacetime curvature singularities. Cosmic dynamics is self-regulating. We discuss the physical basis for these constraints and the implications, pointing out how the framework relates and helps resolve standing puzzl...

  20. Constraints on Spontaneous Entrainment

    Directory of Open Access Journals (Sweden)

    Richardson Michael J.

    2011-12-01

    Full Text Available Past research has revealed that a person's rhythmic limb movements become spontaneously entrained to an environmental rhythm if a. visual information about the environmental rhythm is available and b. its frequency of the environmental rhythm is near that of the person's movements. Further, this research has demonstrated that if the eyes track the environmental stimulus, the spontaneous entrainment to the environmental rhythm is strengthened. Experiments were performed to investigate two hypotheses that could explain this eye-tracking enhancement of spontaneous entrainment. One hypothesis is that eye tracking allows for the pick up of important coordinative information at the turn-around points of a movement trajectory. Another hypothesis is that the limb movements entrain to the moving eyes through a neuromotor synergy linking the eyes and limb. Results of these experiments will help delineate the informational and dynamical constraints that can impact the acquisition of skilled actions.

  1. Volunteer kinematics and reaction in lateral emergency maneuver tests.

    Science.gov (United States)

    Rooij, L van; Elrofai, H; Philippens, M M G M; Daanen, H A M

    2013-11-01

    It is important to understand human kinematics and muscle activation patterns in emergency maneuvers for the design of safety systems and for the further development of human models. The objective of this study was to quantify kinematic behavior and muscle activation in simulated steering tests in several realistic conditions. In total 108 tests were performed with 10 volunteers undergoing purely lateral maneuvers at 5 m/s^2 deceleration or simulated lane change maneuvers at 5 m/s^2 peak acceleration and peak yaw velocity of 25 °/s. Test subjects were seated on a rigid seat and restrained by a 4-point belt with retractor. Driver subjects were instructed to be relaxed or braced and to hold the steering wheel while passenger subjects were instructed to put their hands on their thighs. Subjects were instrumented with photo markers that were tracked with 3D high- speed stereo cameras and with electromyography (EMG) electrodes on 8 muscles. Corridors of head displacement, pitch and roll and displacement of T1, shoulder, elbow, hand and knee were created representing mean response and standard deviation of all subjects. In lane change tests for the passenger configuration significant differences were observed in mean peak of head left lateral displacement between the relaxed and the braced volunteers, i.e. 171 mm (σ=58, n=21) versus 121 mm (σ=46, n=17), respectively. Sitting in a relaxed position led to significantly lower muscle activity of the neck muscles. It was concluded that significantly more upper body motion and lower muscle activity was observed for relaxed subjects than for braced subjects.

  2. Kinematics of the Ethiopian Rift and Absolute motion of Africa and Somalia Plates

    Science.gov (United States)

    Muluneh, A. A.; Cuffaro, M.; Doglioni, C.

    2013-12-01

    The Ethiopian Rift (ER), in the northern part of East African Rift System (EARS), forms a boundary zone accommodating differential motion between Africa and Somalia Plates. Its orientation was influenced by the inherited Pan-African collisional system and related lithospheric fabric. We present the kinematics of ER derived from compilation of geodetic velocities, focal mechanism inversions, structural data analysis, and construction of geological profiles. GPS velocity field shows a systematic eastward magnitude increase in NE direction in the central ER. In the same region, incremental extensional strain axes recorded by earthquake focal mechanism and fault slip inversion show ≈N1000E orientation. This deviation between GPS velocity trajectories and orientation of incremental extensional strain is developed due to left lateral transtensional deformation. This interpretation is consistent with the en-échelon pattern of tensional and transtensional faults, the distribution of the volcanic centers, and the asymmetry of the rift itself. Small amount of vertical axis blocks rotation, sinistral strike slip faults and dyke intrusions in the rift accommodate the transtensional deformation. We analyzed the kinematics of ER relative to Deep and Shallow Hot Spot Reference Frames (HSRF). Comparison between the two reference frames shows different kinematics in ER and also Africa and Somalia plate motion both in magnitude and direction. Plate spreading direction in shallow HSRF (i.e. the source of the plumes locates in the asthenosphere) and the trend of ER deviate by about 27°. Shearing and extension across the plate boundary zone contribute both to the style of deformation and overall kinematics in the rift. We conclude that the observed long wavelength kinematics and tectonics are consequences of faster SW ward motion of Africa than Somalia in the shallow HSRF. This reference frame seems more consistent with the geophysical and geological constraints in the Rift. The

  3. Support vector machine for classification of walking conditions using miniature kinematic sensors.

    Science.gov (United States)

    Lau, Hong-Yin; Tong, Kai-Yu; Zhu, Hailong

    2008-06-01

    A portable gait analysis and activity-monitoring system for the evaluation of activities of daily life could facilitate clinical and research studies. This current study developed a small sensor unit comprising an accelerometer and a gyroscope in order to detect shank and foot segment motion and orientation during different walking conditions. The kinematic data obtained in the pre-swing phase were used to classify five walking conditions: stair ascent, stair descent, level ground, upslope and downslope. The kinematic data consisted of anterior-posterior acceleration and angular velocity measured from the shank and foot segments. A machine learning technique known as support vector machine (SVM) was applied to classify the walking conditions. SVM was also compared with other machine learning methods such as artificial neural network (ANN), radial basis function network (RBF) and Bayesian belief network (BBN). The SVM technique was shown to have a higher performance in classification than the other three methods. The results using SVM showed that stair ascent and stair descent could be distinguished from each other and from the other walking conditions with 100% accuracy by using a single sensor unit attached to the shank segment. For classification results in the five walking conditions, performance improved from 78% using the kinematic signals from the shank sensor unit to 84% by adding signals from the foot sensor unit. The SVM technique with the portable kinematic sensor unit could automatically recognize the walking condition for quantitative analysis of the activity pattern.

  4. Transcriptional activities of methanogens and methanotrophs vary with methane emission flux in rice soils under chronic nutrient constraints of phosphorus and potassium

    Science.gov (United States)

    Sheng, Rong; Chen, Anlei; Zhang, Miaomiao; Whiteley, Andrew S.; Kumaresan, Deepak; Wei, Wenxue

    2016-12-01

    Nutrient status in soil is crucial for the growth and development of plants which indirectly or directly affect the ecophysiological functions of resident soil microorganisms. Soil methanogens and methanotrophs can be affected by soil nutrient availabilities and plant growth, which in turn modulate methane (CH4) emissions. Here, we assessed whether deficits in soil-available phosphorus (P) and potassium (K) modulated the activities of methanogens and methanotrophs in a long-term (20 year) experimental system involving limitation in either one or both nutrients. Results showed that a large amount of CH4 was emitted from paddy soil at rice tillering stage (flooding) while CH4 flux was minimum at ripening stage (drying). Compared to soils amended with NPK fertiliser treatment, the soils without P input significantly reduced methane flux rates, whereas those without K input did not. Under P limitation, methanotroph transcript copy number significantly increased in tandem with a decrease in methanogen transcript abundance, suggesting that P-deficiency-induced changes in soil physio-chemical properties, in tandem with rice plant growth, might constrain the activity of methanogens, whereas the methanotrophs might be adaptive to this soil environment. In contrast, lower transcript abundance of both methanogen and methanotrophs were observed in K-deficient soils. Assessments of community structures based upon transcripts indicated that soils deficient in P induced greater shifts in the active methanotrophic community than K-deficient soils, while similar community structures of active methanogens were observed in both treatments. These results suggested that the population dynamics of methanogens and methanotrophs could vary along with the changes in plant growth states and soil properties induced by nutrient deficiency.

  5. Step kinematic calibration of a 3-DOF planar parallel kinematic machine tool

    Institute of Scientific and Technical Information of China (English)

    CHANG Peng; WANG JinSong; LI TieMin; LIU XinJun; GUAN LiWen

    2008-01-01

    This paper presents a novel step kinematic calibration method for a 3 degree-of-freedom (DOF) planar parallel kinematic machine tool, based on the minimal linear combinations (MLCs) of error parameters. The method using mapping of linear combinations of parameters in error transfer multi-parameters coupling system changes the modeling, identification and error compensation of geometric pa-rameters in the general kinematic calibration into those of linear combinations of parameters. By using the four theorems of the MLCs, the sets of the MLCs that are respectively related to the relative precision and absolute precision are determined. All simple and feasible measurement methods in practice are given, and identifica-tion analysis of the set of the MLCs for each measurement is carried out. According to the identification analysis results, a step calibration including step measurement, step identification and step error compensation is determined by taking into ac-count both measurement costs and observability. The experiment shows that the proposed method has the following merits: (1) the parameter errors that cannot influence precision are completely avoided; (2) it reflects the mapping of linear combinations of parameters more accurately and enhances the precision of identi-fication; and (3) the method is robust, efficient and effective, so that the errors in position and orientation are kept at the same order of the measurement noise. Due to these merits, the present method is attractive for the 3-DOF planar parallel ki-nematic machine tool and can be also applied to other parallel kinematic machine tools with weakly nonlinear kinematics.

  6. How realistic are flat-ramp-flat fault kinematic models? Comparing mechanical and kinematic models

    Science.gov (United States)

    Cruz, L.; Nevitt, J. M.; Hilley, G. E.; Seixas, G.

    2015-12-01

    Rock within the upper crust appears to deform according to elasto-plastic constitutive rules, but structural geologists often employ kinematic descriptions that prescribe particle motions irrespective of these physical properties. In this contribution, we examine the range of constitutive properties that are approximately implied by kinematic models by comparing predicted deformations between mechanical and kinematic models for identical fault geometric configurations. Specifically, we use the ABAQUS finite-element package to model a fault-bend-fold geometry using an elasto-plastic constitutive rule (the elastic component is linear and the plastic failure occurs according to a Mohr-Coulomb failure criterion). We varied physical properties in the mechanical model (i.e., Young's modulus, Poisson ratio, cohesion yield strength, internal friction angle, sliding friction angle) to determine the impact of each on the observed deformations, which were then compared to predictions of kinematic models parameterized with identical geometries. We found that a limited sub-set of physical properties were required to produce deformations that were similar to those predicted by the kinematic models. Specifically, mechanical models with low cohesion are required to allow the kink at the bottom of the flat-ramp geometry to remain stationary over time. Additionally, deformations produced by steep ramp geometries (30 degrees) are difficult to reconcile between the two types of models, while lower slope gradients better conform to the geometric assumptions. These physical properties may fall within the range of those observed in laboratory experiments, suggesting that particle motions predicted by kinematic models may provide an approximate representation of those produced by a physically consistent model under some circumstances.

  7. Step kinematic calibration of a 3-DOF planar parallel kinematic machine tool

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    This paper presents a novel step kinematic calibration method for a 3 degree-of-freedom(DOF) planar parallel kinematic machine tool,based on the minimal linear combinations(MLCs) of error parameters.The method using mapping of linear combinations of parameters in error transfer multi-parameters coupling system changes the modeling,identification and error compensation of geometric parameters in the general kinematic calibration into those of linear combinations of parameters.By using the four theorems of the MLCs,the sets of the MLCs that are respectively related to the relative precision and absolute precision are determined.All simple and feasible measurement methods in practice are given,and identification analysis of the set of the MLCs for each measurement is carried out.According to the identification analysis results,a step calibration including step measurement,step identification and step error compensation is determined by taking into account both measurement costs and observability.The experiment shows that the proposed method has the following merits:(1) the parameter errors that cannot influence precision are completely avoided;(2) it reflects the mapping of linear combinations of parameters more accurately and enhances the precision of identification;and(3) the method is robust,efficient and effective,so that the errors in position and orientation are kept at the same order of the measurement noise.Due to these merits,the present method is attractive for the 3-DOF planar parallel kinematic machine tool and can be also applied to other parallel kinematic machine tools with weakly nonlinear kinematics.

  8. Tephrochronology of the Mont-Dore volcanic Massif (Massif Central, France): new 40Ar/39Ar constraints on the Late Pliocene and Early Pleistocene activity

    Science.gov (United States)

    Nomade, Sébastien; Pastre, Jean-François; Nehlig, Pierre; Guillou, Hervé; Scao, Vincent; Scaillet, Stéphane

    2014-03-01

    The Mont-Dore Massif (500 km2), the youngest stratovolcano of the French Massif Central, consists of two volcanic edifices: the Guéry and the Sancy. To improve our knowledge of the oldest explosive stages of the Mont-Dore Massif, we studied 40Ar/39Ar-dated (through single-grain laser and step-heating experiments) 11 pyroclastic units from the Guéry stratovolcano. We demonstrate that the explosive history of the Guéry can be divided into four cycles of explosive eruption activity between 3.09 and 1.46 Ma (G.I to G.IV). We have also ascertained that deposits associated with the 3.1-3.0-Ma rhyolitic activity, which includes the 5-km3 "Grande Nappe" ignimbrite, are not recorded in the central part of the Mont-Dore Massif. All the pyroclastites found in the left bank of the Dordogne River belong to a later explosive phase (2.86-2.58 Ma, G.II) and were channelled down into valleys or topographic lows where they are currently nested. This later activity also gave rise to most of the volcanic products in the Perrier Plateau (30 km east of the Mont-Dore Massif); three quarters of the volcano-sedimentary sequence (up to 100 m thick) was emplaced within less than 20 ky, associated with several flank collapses in the northeastern part of the Guéry. The age of the "Fournet flora" (2.69 ± 0.01 Ma) found within an ash bed belonging to G.II suggests that temperate forests already existed in the French Massif Central before the Pliocene/Pleistocene boundary. The Guéry's third explosive eruption activity cycle (G.III) lasted between 2.36 and 1.91 Ma. It encompassed the Guéry Lake and Morangie pumice and ash deposits, as well as seven other important events recorded as centimetric ash beds some 60 to 100 km southeast of the Massif in the Velay region. We propose a general tephrochronology for the Mont-Dore stratovolcano covering the last 3.1 My. This chronology is based on 44 40Ar/39Ar-dated events belonging to eight explosive eruption cycles each lasting between 100 and 200

  9. Wave kinematics and response of slender offshore structures. Vol 4: Wave kinematics

    Energy Technology Data Exchange (ETDEWEB)

    Riber, H.J.

    1999-08-01

    The kinematics of large surface waves has been measured by means of sonar's placed on the sea floor at the Tyra field. Measurements from the most severe storm are analysed and extreme wave velocity profiles are compared to Stoke wave velocity profiles. Statistical distributions of crest velocity and wave celerity are presented. The analysis shows how the deviation from the Stokes prediction varies with wave heights and steepness. Analyses of the directional wave field leads to the conclusion that the extreme waves are three-dimensional. It is shown that the peculiar kinematics of extreme waves is of great relevance to the design of jacket type structures. (au)

  10. Kinematic and electromyographic analysis in patients with patellofemoral pain syndrome during single leg triple hop test.

    Science.gov (United States)

    Kalytczak, Marcelo Martins; Lucareli, Paulo Roberto Garcia; Dos Reis, Amir Curcio; Bley, André Serra; Biasotto-Gonzalez, Daniela Aparecida; Correa, João Carlos Ferrari; Politti, Fabiano

    2016-09-01

    Possible delays in pre-activation or deficiencies in the activity of the dynamic muscle stabilizers of the knee and hip joints are the most common causes of the patellofemoral pain syndrome (PFPS). The aim of the study was to compare kinematic variables and electromyographic activity of the vastus lateralis, biceps femoris, gluteus maximus and gluteus medius muscles between patients with PFPS and health subjects during the single leg triple hop test (SLTHT). This study included 14 female with PFPS (PFPS group) and 14 female healthy with no history of knee pain (Healthy group). Kinematic and EMG data ware collected through participants performed a single session of the SLTHT. The PFPS group exhibited a significant increase (p<0.05) in the EMG activity of the biceps femoris and vastus lateralis muscles, when compared with the healthy group in pre-activity and during the stance phase. This same result was also found for the vastus lateralis muscle (p<0.05) when analyzing the EMG activity during the eccentric phase of the stance phase. In kinematic analysis, no significant differences were found between the groups. These results indicate that biceps femoris and vastus lateralis muscles mainly during the pre-activation phase and stance phases of the SLTHT are more active in PFPS group among healthy group.

  11. A learning-based markerless approach for full-body kinematics estimation in-natura from a single image.

    Science.gov (United States)

    Drory, Ami; Li, Hongdong; Hartley, Richard

    2017-01-31

    We present a supervised machine learning approach for markerless estimation of human full-body kinematics for a cyclist from an unconstrained colour image. This approach is motivated by the limitations of existing marker-based approaches restricted by infrastructure, environmental conditions, and obtrusive markers. By using a discriminatively learned mixture-of-parts model, we construct a probabilistic tree representation to model the configuration and appearance of human body joints. During the learning stage, a Structured Support Vector Machine (SSVM) learns body parts appearance and spatial relations. In the testing stage, the learned models are employed to recover body pose via searching in a test image over a pyramid structure. We focus on the movement modality of cycling to demonstrate the efficacy of our approach. In natura estimation of cycling kinematics using images is challenging because of human interaction with a bicycle causing frequent occlusions. We make no assumptions in relation to the kinematic constraints of the model, nor the appearance of the scene. Our technique finds multiple quality hypotheses for the pose. We evaluate the precision of our method on two new datasets using loss functions. Our method achieves a score of 91.1 and 69.3 on mean Probability of Correct Keypoint (PCK) measure and 88.7 and 66.1 on the Average Precision of Keypoints (APK) measure for the frontal and sagittal datasets respectively. We conclude that our method opens new vistas to robust user-interaction free estimation of full body kinematics, a prerequisite to motion analysis.

  12. Seismological Constraints on Geodynamics

    Science.gov (United States)

    Lomnitz, C.

    2004-12-01

    Earth is an open thermodynamic system radiating heat energy into space. A transition from geostatic earth models such as PREM to geodynamical models is needed. We discuss possible thermodynamic constraints on the variables that govern the distribution of forces and flows in the deep Earth. In this paper we assume that the temperature distribution is time-invariant, so that all flows vanish at steady state except for the heat flow Jq per unit area (Kuiken, 1994). Superscript 0 will refer to the steady state while x denotes the excited state of the system. We may write σ 0=(J{q}0ṡX{q}0)/T where Xq is the conjugate force corresponding to Jq, and σ is the rate of entropy production per unit volume. Consider now what happens after the occurrence of an earthquake at time t=0 and location (0,0,0). The earthquake introduces a stress drop Δ P(x,y,z) at all points of the system. Response flows are directed along the gradients toward the epicentral area, and the entropy production will increase with time as (Prigogine, 1947) σ x(t)=σ 0+α {1}/(t+β )+α {2}/(t+β )2+etc A seismological constraint on the parameters may be obtained from Omori's empirical relation N(t)=p/(t+q) where N(t) is the number of aftershocks at time t following the main shock. It may be assumed that p/q\\sim\\alpha_{1}/\\beta times a constant. Another useful constraint is the Mexican-hat geometry of the seismic transient as obtained e.g. from InSAR radar interferometry. For strike-slip events such as Landers the distribution of \\DeltaP is quadrantal, and an oval-shaped seismicity gap develops about the epicenter. A weak outer triggering maxiμm is found at a distance of about 17 fault lengths. Such patterns may be extracted from earthquake catalogs by statistical analysis (Lomnitz, 1996). Finally, the energy of the perturbation must be at least equal to the recovery energy. The total energy expended in an aftershock sequence can be found approximately by integrating the local contribution over

  13. Analysis of the kinematic characteristics of a high-speed parallel robot with Schönflies motion: Mobility, kinematics, and singularity

    Science.gov (United States)

    Xie, Fugui; Liu, Xin-Jun

    2016-06-01

    This study introduces a high-speed parallel robot with Schönflies motion. This robot exhibits a promising prospect in realizing high-speed pick-andplace manipulation for packaging production lines. The robot has four identical limbs and a single platform. Its compact structure and single-platform concept provides this robot with good dynamic response potential. A line graph method based on Grassmann line geometry is used to investigate the mobility characteristics of the proposed robot. A generalized Blanding rule is also introduced into this procedure to realize mutual conversion between the line graphs for motions and constraints. Subsequently, the inverse kinematics is derived, and the singularity issue of the robot is investigated using both qualitative and quantitative approaches. Input and output transmission singularity indices are defined based on the reciprocal product in screw theory and the virtual coefficient by considering motion/force transmission performance. Thereafter, the singular loci of the proposed robot with specific geometric parameters are derived. The mobility analysis, inverse kinematics modeling, and singularity analysis conducted in this study are helpful in developing the robot.

  14. On Constraints in Assembly Planning

    Energy Technology Data Exchange (ETDEWEB)

    Calton, T.L.; Jones, R.E.; Wilson, R.H.

    1998-12-17

    Constraints on assembly plans vary depending on product, assembly facility, assembly volume, and many other factors. Assembly costs and other measures to optimize vary just as widely. To be effective, computer-aided assembly planning systems must allow users to express the plan selection criteria that appIy to their products and production environments. We begin this article by surveying the types of user criteria, both constraints and quality measures, that have been accepted by assembly planning systems to date. The survey is organized along several dimensions, including strategic vs. tactical criteria; manufacturing requirements VS. requirements of the automated planning process itself and the information needed to assess compliance with each criterion. The latter strongly influences the efficiency of planning. We then focus on constraints. We describe a framework to support a wide variety of user constraints for intuitive and efficient assembly planning. Our framework expresses all constraints on a sequencing level, specifying orders and conditions on part mating operations in a number of ways. Constraints are implemented as simple procedures that either accept or reject assembly operations proposed by the planner. For efficiency, some constraints are supplemented with special-purpose modifications to the planner's algorithms. Fast replanning enables an interactive plan-view-constrain-replan cycle that aids in constraint discovery and documentation. We describe an implementation of the framework in a computer-aided assembly planning system and experiments applying the system to a number of complex assemblies, including one with 472 parts.

  15. An Introduction to 'Creativity Constraints'

    DEFF Research Database (Denmark)

    Onarheim, Balder; Biskjær, Michael Mose

    2013-01-01

    Constraints play a vital role as both restrainers and enablers in innovation processes by governing what the creative agent/s can and cannot do, and what the output can and cannot be. Notions of constraints are common in creativity research, but current contributions are highly dispersed due to n...

  16. Nonholonomic constraints with fractional derivatives

    Energy Technology Data Exchange (ETDEWEB)

    Tarasov, Vasily E [Skobeltsyn Institute of Nuclear Physics, Moscow State University, Moscow 119992 (Russian Federation); Zaslavsky, George M [Courant Institute of Mathematical Sciences, New York University, 251 Mercer St, New York, NY 10012 (United States)

    2006-08-04

    We consider the fractional generalization of nonholonomic constraints defined by equations with fractional derivatives and provide some examples. The corresponding equations of motion are derived using variational principle. We prove that fractional constraints can be used to describe the evolution of dynamical systems in which some coordinates and velocities are related to velocities through a power-law memory function.

  17. Constraint Programming for Context Comprehension

    DEFF Research Database (Denmark)

    Christiansen, Henning

    2014-01-01

    of knowledge. The language of Constraint Handling Rules, CHR, is suggested for defining constraint solvers that reflect “world knowledge” for the given domain, and driver algorithms may be ex- pressed in Prolog or additional rules of CHR. It is argued that this way of doing context comprehension is an instance...

  18. Minimal Flavor Constraints for Technicolor

    DEFF Research Database (Denmark)

    Sakuma, Hidenori; Sannino, Francesco

    2010-01-01

    We analyze the constraints on the the vacuum polarization of the standard model gauge bosons from a minimal set of flavor observables valid for a general class of models of dynamical electroweak symmetry breaking. We will show that the constraints have a strong impact on the self-coupling and mas...

  19. A Novel Algorithm for the Generation of Distinct Kinematic Chain

    Science.gov (United States)

    Medapati, Sreenivasa Reddy; Kuchibhotla, Mallikarjuna Rao; Annambhotla, Balaji Srinivasa Rao

    2016-07-01

    Generation of distinct kinematic chains is an important topic in the design of mechanisms for various industrial applications i.e., robotic manipulator, tractor, crane etc. Many researchers have intently focused on this area and explained various processes of generating distinct kinematic chains which are laborious and complex. It is desirable to enumerate the kinematic chains systematically to know the inherent characteristics of a chain related to its structure so that all the distinct chains can be analyzed in depth, prior to the selection of a chain for a purpose. This paper proposes a novel and simple method with set of rules defined to eliminate isomorphic kinematic chains generating distinct kinematic chains. Also, this method simplifies the process of generating distinct kinematic chains even at higher levels i.e., 10-link, 11-link with single and multiple degree of freedom.

  20. FORWARD KINEMATICS ANALYSIS FOR A NOVEL 5-DOF PARALLEL MECHANISM USING TETRAHEDRON CONFIGURATIONS

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Forward kinematics analysis of a novel 5-DOF parallel mechanism using tetrahedron configurations is presented. Such mechanism is suitable to many tasks requiring less than 6 DOFs. It consists of a movable platform connected to the base by five identical 6-DOF active limbs plus one active limb with its DOF being exactly the same as the specified DOF of the movable platform, which leads to its legs' topology 4-UPS/UPU. Based on the tetrahedron geometry, both closed-form solution with an extra sensor and numerical method using iterative algorithm are employed to obtain the forward kinematics solutions of the mechanism. Compared with the conventional methods, the proposed closed-form solution has the advantages in automatically avoiding unnecessary complex roots and getting a unique solution for the forward kinematics. Finally, an example shows that the proposed numerical algorithm is so effective that it enables a real-time forward kinematics solution to be achieved and the initial value can be chosen easily.

  1. Locomotion of Gymnarchus Niloticus: Experiment and Kinematics

    Institute of Scientific and Technical Information of China (English)

    Li Fei; Hu Tian-jiang; Wang Guang-ming; Shen Lin-cheng

    2005-01-01

    In addition to forward undulatory swimming, Gymnarchus niloticus can swim via undulations of the dorsal fin while the body axis remains straight; furthermore, it swims forward and backward in a similar way, which indicates that the undulation of the dorsal fin can simultaneously provide bidirectional propulsive and maneuvering forces with the help of the tail fin. A high-resolution Charge-Coupled Device (CCD) imaging camera system is used to record kinematics of steady swimming as well as maneuvering in G. niloticus. Based on experimental data, this paper discusses the kinematics ( cruising speed, wave speed, cycle frequency, amplitude, lateral displacement) of forward as well as backward swimming and maneuvering.During forward swimming, the propulsive force is generated mainly by undulations of the dorsal fin while the body axis remains straight. The kinematic parameters (wave speed, wavelength, cycle frequency, amplitude ) have statistically significant correlations with cruising speed. In addition, the yaw at the head is minimal during steady swimming. From experimental data, the maximal lateral displacement of head is not more than 1% of the body length, while the maximal lateral displacement of the whole body is not more than 5% of the body length. Another important feature is that G. niloticus swims backwards using an undulatory mechanism that resembles the forward undulatory swimming mechanism. In backward swimming, the increase of lateral displacement of the head is comparatively significant; the amplitude profiles of the propulsive wave along the dorsal fin are significantly different from those in forward swimming. When G. niloticus does fast maneuvering, its body is first bent into either a C shape or an S shape, then it is rapidly unwound in a travelling wave fashion. It rarely maneuvers without the help of the tail fin and body bending.

  2. Kinematics of transition during human accelerated sprinting

    Directory of Open Access Journals (Sweden)

    Ryu Nagahara

    2014-07-01

    Full Text Available This study investigated kinematics of human accelerated sprinting through 50 m and examined whether there is transition and changes in acceleration strategies during the entire acceleration phase. Twelve male sprinters performed a 60-m sprint, during which step-to-step kinematics were captured using 60 infrared cameras. To detect the transition during the acceleration phase, the mean height of the whole-body centre of gravity (CG during the support phase was adopted as a measure. Detection methods found two transitions during the entire acceleration phase of maximal sprinting, and the acceleration phase could thus be divided into initial, middle, and final sections. Discriminable kinematic changes were found when the sprinters crossed the detected first transition—the foot contacting the ground in front of the CG, the knee-joint starting to flex during the support phase, terminating an increase in step frequency—and second transition—the termination of changes in body postures and the start of a slight decrease in the intensity of hip-joint movements, thus validating the employed methods. In each acceleration section, different contributions of lower-extremity segments to increase in the CG forward velocity—thigh and shank for the initial section, thigh, shank, and foot for the middle section, shank and foot for the final section—were verified, establishing different acceleration strategies during the entire acceleration phase. In conclusion, there are presumably two transitions during human maximal accelerated sprinting that divide the entire acceleration phase into three sections, and different acceleration strategies represented by the contributions of the segments for running speed are employed.

  3. Inverting Source Time Functions to determine the fault kinematic characteristics

    Science.gov (United States)

    Toraldo Serra, E. M.; Orefice, A.; Emolo, A.; Zollo, A.

    2012-04-01

    In seismology, the analisys of source kinematic parameters (slip-rate and rupture velocity ecc.) is a fundamental way to study the time-history of the rupture process that occurs during a seismic event. To this end various method to reconstruct source kinematics models from the inversion of seismogram have been proposed during the time. In this work we present an alternative methodology to infer source models. We aim, indeed, at obtaining the slip and rupture velocity distribution on the fault plane inverting the apparent Source Time Functions (STFs). This kind of analysis, rather than a classical inversion based on a direct study of seismograms recorded at various stations, may have several advantages. A major advantage is related to the possibility to overcome in the forward modeling any problem related to the computation of the Green's function, as the choice of the correct and reliable propagation model. To retrieve reliable STF, we apply the stabilized deconvolution technique proposed by Vallée [2004]. Based on Empirical Green's Functions (EGF) approach, this technique integrates in the deconvolution process four physical constraints on the STFs, that are causality, positivity, limited duration, and equal area. In any case the EGF approach suffers from certain limitations related to the selection of valuable Empirical Green Function, especially for small events. The approach used to invert the STFs is based on the technique of Emolo and Zollo [2005] to invert strong-motion data. In particular, the slip and the rupture velocity values are specified only at a set of control-points on the fault plane and their distributions on the whole fault are then obtained by a bicubic interpolation. The final slip and rupture velocity values at the fault-grid nodes are then determined by searching for the maximum of a fitness function (based of comparison between real and synthetic STFs) by using the Genetic Algorithm. The number of control-points is progressively increased

  4. Kinematic analysis for the implementation of landslide mitigation measures

    Science.gov (United States)

    Delmonaco, Giuseppe; Margottini, Claudio; Spizzichino, Daniele

    2010-05-01

    The present work is finalised at the implementation of a landslide risk mitigation master plan of the ancient citadel of Machu Picchu. After the warning launched in March 2001, by the scientific community on potential collapse of the citadel from a near-disastrous landslide event different studies have been promoted to reconstruct landslide activity and suggest landslide risk mitigation measures for the protection and conservation of Machu Picchu cultural heritage. A site-scale analysis has been implemented following the application and integration of geomechanical classifications, ambient noise measurements and structural and kinematical analysis. The geology of the area is characterized by granitoid bodies that had been emplaced in the axial zones of the main rift system that are now exposed at the highest altitudes, together with country rocks (Precambrian and Lower Paleozoic metamorphics) originally constituting the rift ‘roots'. The bedrock of the Inca citadel of Machu Picchu is mainly composed by granite and subordinately granodiorite. This is mainly located in the lower part of the slopes. Superficially, the granite is jointed in blocks with variable dimensions, promoted by local structural setting. Single blocks vary from 10-1 to about 200 m3. Soil cover, widely outcropping in the area, is mainly composed by individual blocks and subordinately by coarse materials originated by chemical and physical weathering of minerals. Regional tectonic uplift and structural setting rule the general morphological features of the area and as a consequence, landslide type and evolution. Rock falls, rock slides, debris flows and debris slides are the main landslide typologies affecting the citadel slopes. In the last mission in May 2009, elastic and deformation rock parameters have been collected using a passive seismic innovative technique based on natural microtremor measurements and geostructural scan lines elaboration. A landslide zoning of the citadel has been

  5. Theory of gearing kinematics, geometry, and synthesis

    CERN Document Server

    Radzevich, Stephen P

    2012-01-01

    The first book of its kind, Theory of Gearing: Kinematics, Geometry, and Synthesis systematically develops a scientific theory of gearing that makes it possible to synthesize novel gears with the desired performance. Written by a leading gearing expert who holds more than 200 patents, it presents a modern methodology for gear design. The proposed theory is based on a key postulate: all the design parameters for an optimal gear pair for a particular application can be derived from (a) a given configuration of the rotation vectors of the driving and driven shafts and (b) the power transmitted by

  6. Kinematics and Fluid Dynamics of Jellyfish Maneuvering

    Science.gov (United States)

    Miller, Laura; Hoover, Alex

    2014-11-01

    Jellyfish propel themselves through the water through periodic contractions of their elastic bells. Some jellyfish, such as the moon jellyfish Aurelia aurita and the upside down jellyfish Cassiopea xamachana, can perform turns via asymmetric contractions of the bell. The fluid dynamics of jellyfish forward propulsion and turning is explored here by analyzing the contraction kinematics of several species and using flow visualization to quantify the resulting flow fields. The asymmetric contraction and structure of the jellyfish generates asymmetries in the starting and stopping vortices. This creates a diagonal jet and a net torque acting on the jellyfish. Results are compared to immersed boundary simulations

  7. Spectral gaps, inertial manifolds and kinematic dynamos

    Energy Technology Data Exchange (ETDEWEB)

    Nunez, Manuel [Departamento de Analisis Matematico, Universidad de Valladolid, 47005 Valladolid (Spain)]. E-mail: mnjmhd@am.uva.es

    2005-10-17

    Inertial manifolds are desirable objects when ones wishes a dynamical process to behave asymptotically as a finite-dimensional ones. Recently [Physica D 194 (2004) 297] these manifolds are constructed for the kinematic dynamo problem with time-periodic velocity. It turns out, however, that the conditions imposed on the fluid velocity to guarantee the existence of inertial manifolds are too demanding, in the sense that they imply that all the solutions tend exponentially to zero. The inertial manifolds are meaningful because they represent different decay rates, but the classical dynamos where the magnetic field is maintained or grows are not covered by this approach, at least until more refined estimates are found.

  8. Confined kinematics of suspended rigid fibres

    Science.gov (United States)

    Scheuer, A.; Perez, M.; Abisset-Chavanne, E.; Chinesta, F.; Keunings, R.

    2016-10-01

    We address the extension of Jeffery's model, governing the orientation of rods immersed in a Newtonian fluid, to confined regimes occurring when the thickness of the flow domain is narrower than the rod length. The main modelling ingredients concern: (i) the consideration of the rod interactions with one or both gap walls and their effects on the rod orientation kinematics; (ii) the consideration of non-uniform strain rates at the scale of the rod, requiring higher-order descriptions. Such scenarios are very close to those encountered in real composites forming processes and have never been appropriately addressed from a microstructural point of view.

  9. A robotic exoskeleton to treat crouch gait from cerebral palsy: Initial kinematic and neuromuscular evaluation.

    Science.gov (United States)

    Lerner, Zachary F; Damiano, Diane L; Bulea, Thomas C; Lerner, Zachary F; Damiano, Diane L; Bulea, Thomas C; Damiano, Diane L; Lerner, Zachary F; Bulea, Thomas C

    2016-08-01

    A robotic exoskeleton was designed for individuals with crouch gait caused by cerebral palsy with the intent to supplement existing muscle function during walking. The aim of this study was to evaluate how powered knee extension assistance provided during stance and swing phases of the gait cycle affect knee kinematics, and knee flexor and extensor muscle activity. Muscle activity and kinematic data were collected from four individuals with crouch gait from cerebral palsy during their normal walking condition and while walking with the exoskeleton under stance, swing, and stance & swing assistance. The exoskeleton was effective in reducing crouch by an average of 13.8° in three of the four participants when assistance was provided during the stance phase; assistance during the swing phase alone was ineffective. Peak knee extensor activity was maintained for all of the conditions during the stance and swing phases. Integrated (i.e. area under the curve) knee extensor activity decreased in two of the subjects indicating a more well-modulated activation pattern. Modest increases in peak and integrated antagonist knee flexor activity were exhibited in all participants; the subject without kinematic improvement had the greatest increase. While the exoskeleton was well tolerated, additional training with a focus on reducing knee flexor activity may lead to further improvements in crouch gait reduction.

  10. Static and kinematic formulation of planar reciprocal assemblies

    DEFF Research Database (Denmark)

    Parigi, Dario; Sassone, Mario; Kirkegaard, Poul Henning

    2014-01-01

    Planar reciprocal frames are two dimensional structures formed by elements joined together according to the principle of structural reciprocity. In this paper a rigorous formulation of the static and kinematic problem is proposed and developed extending the theory of pin-jointed assemblies....... This formulation is used to evaluate the static and kinematic determinacy of reciprocal assemblies from the properties of their equilibrium and kinematic matrices...

  11. Direct Kinematic modeling of 6R Robot using Robotics Toolbox

    OpenAIRE

    Prashant Badoni

    2016-01-01

    The traditional approaches are insufficient to solve the complex kinematics problems of the redundant robotic manipulators. To overcome such intricacy, Peter Corke’s Robotics Toolbox [1] is utilized in the present study. This paper aims to model the direct kinematics of a 6 degree of freedom (DOF) Robotic arm. The Toolbox uses the Denavit-Hartenberg (DH) Methodology [2] to compute the kinematic model of the robot.

  12. Direct Kinematic modeling of 6R Robot using Robotics Toolbox

    Directory of Open Access Journals (Sweden)

    Prashant Badoni

    2016-01-01

    Full Text Available The traditional approaches are insufficient to solve the complex kinematics problems of the redundant robotic manipulators. To overcome such intricacy, Peter Corke’s Robotics Toolbox [1] is utilized in the present study. This paper aims to model the direct kinematics of a 6 degree of freedom (DOF Robotic arm. The Toolbox uses the Denavit-Hartenberg (DH Methodology [2] to compute the kinematic model of the robot.

  13. Changes in knee kinematics following total knee arthroplasty.

    Science.gov (United States)

    Akbari Shandiz, Mohsen; Boulos, Paul; Saevarsson, Stefan Karl; Yoo, Sam; Miller, Stephen; Anglin, Carolyn

    2016-04-01

    Total knee arthroplasty (TKA) changes the knee joint in both intentional and unintentional, known and unknown, ways. Patellofemoral and tibiofemoral kinematics play an important role in postoperative pain, function, satisfaction and revision, yet are largely unknown. Preoperative kinematics, postoperative kinematics or changes in kinematics may help identify causes of poor clinical outcome. Patellofemoral kinematics are challenging to record since the patella is obscured by the metal femoral component in X-ray and moves under the skin. The purpose of this study was to determine the kinematic degrees of freedom having significant changes and to evaluate the variability in individual changes to allow future study of patients with poor clinical outcomes. We prospectively studied the 6 degrees of freedom patellofemoral and tibiofemoral weightbearing kinematics, tibiofemoral contact points and helical axes of rotation of nine subjects before and at least 1 year after total knee arthroplasty using clinically available computed tomography and radiographic imaging systems. Normal kinematics for healthy individuals were identified from the literature. Significant differences existed between pre-TKA and post-TKA kinematics, with the post-TKA kinematics being closer to normal. While on average the pre-total knee arthroplasty knees in this group displayed no pivoting (only translation), individually only five knees displayed this behaviour (of these, two showed lateral pivoting, one showed medial pivoting and one showed central pivoting). There was considerable variability postoperatively as well (five central, two lateral and two medial pivoting). Both preop and postop, flexion behaviour was more hinge-like medially and more rolling laterally. Helical axes were more consistent postop for this group. An inclusive understanding of the pre-TKA and post-TKA kinematics and changes in kinematics due to total knee arthroplasty could improve implant design, patient diagnosis and

  14. 3D Kinematics and Hydrodynamic Analysis of Freely Swimming Cetacean

    Science.gov (United States)

    Ren, Yan; Sheinberg, Dustin; Liu, Geng; Dong, Haibo; Fish, Frank; Javed, Joveria

    2015-11-01

    It's widely thought that flexibility and the ability to control flexibility are crucial elements in determining the performance of animal swimming. However, there is a lack of quantification of both span-wise and chord-wise deformation of Cetacean's flukes and associated hydrodynamic performance during actively swimming. To fill this gap, we examined the motion and flexure of both dolphin fluke and orca fluke in steady swimming using a combined experimental and computational approach. It is found that the fluke surface morphing can effectively modulate the flow structures and influence the propulsive performance. Findings from this work are fundamental for understanding key kinematic features of effective Cetacean propulsors, and for quantifying the hydrodynamic force production that naturally occurs during different types of swimming. This work is supported by ONR MURI N00014-14-1-0533 and NSF CBET-1313217.

  15. Tracking whole hand kinematics using extended Kalman filter.

    Science.gov (United States)

    Fu, Qiushi; Santello, Marco

    2010-01-01

    This paper describes the general procedure, model construction, and experimental results of tracking whole hand kinematics using extended Kalman filter (EKF) based on data recorded from active surface markers. We used a hand model with 29 degrees of freedom that consists of hand global posture, wrist, and digits. The marker protocol had 4 markers on the distal forearm and 20 markers on the dorsal surface of the joints of the digits. To reduce computational load, we divided the state space into four sub-spaces, each of which were estimated with an EKF in a specific order. We tested our framework and found reasonably accurate results (2-4 mm tip position error) when sampling tip to tip pinch at 120 Hz.

  16. In Vivo Healthy Knee Kinematics during Dynamic Full Flexion

    Directory of Open Access Journals (Sweden)

    Satoshi Hamai

    2013-01-01

    Full Text Available Healthy knee kinematics during dynamic full flexion were evaluated using 3D-to-2D model registration techniques. Continuous knee motions were recorded during full flexion in a lunge from 85° to 150°. Medial and lateral tibiofemoral contacts and femoral internal-external and varus-valgus rotations were analyzed as a function of knee flexion angle. The medial tibiofemoral contact translated anteroposteriorly, but remained on the center of the medial compartment. On the other hand, the lateral tibiofemoral contact translated posteriorly to the edge of the tibial surface at 150° flexion. The femur exhibited external and valgus rotation relative to the tibia over the entire activity and reached 30° external and 5° valgus rotations at 150° flexion. Kinematics’ data during dynamic full flexion may provide important insight as to the designing of high-flexion total knee prostheses.

  17. Precision Constraints on Extra Fermion Generations

    CERN Document Server

    Erler, Jens

    2010-01-01

    In the recent past there has been renewed interest in the possibility of additional fermion generations. At the same time there have been significant changes in the relevant electroweak (EW) precision constraints, in particular in the interpretation of several of the low energy experiments. We summarize the various motivations for the increased activity regarding extra families and analyze them in view of the latest EW precision data.

  18. Tissue-Mimicking Geometrical Constraints Stimulate Tissue-Like Constitution and Activity of Mouse Neonatal and Human-Induced Pluripotent Stem Cell-Derived Cardiac Myocytes

    Directory of Open Access Journals (Sweden)

    Götz Pilarczyk

    2016-01-01

    Full Text Available The present work addresses the question of to what extent a geometrical support acts as a physiological determining template in the setup of artificial cardiac tissue. Surface patterns with alternating concave to convex transitions of cell size dimensions were used to organize and orientate human-induced pluripotent stem cell (hIPSC-derived cardiac myocytes and mouse neonatal cardiac myocytes. The shape of the cells, as well as the organization of the contractile apparatus recapitulates the anisotropic line pattern geometry being derived from tissue geometry motives. The intracellular organization of the contractile apparatus and the cell coupling via gap junctions of cell assemblies growing in a random or organized pattern were examined. Cell spatial and temporal coordinated excitation and contraction has been compared on plain and patterned substrates. While the α-actinin cytoskeletal organization is comparable to terminally-developed native ventricular tissue, connexin-43 expression does not recapitulate gap junction distribution of heart muscle tissue. However, coordinated contractions could be observed. The results of tissue-like cell ensemble organization open new insights into geometry-dependent cell organization, the cultivation of artificial heart tissue from stem cells and the anisotropy-dependent activity of therapeutic compounds.

  19. Rigid-body kinematics versus flapping kinematics of a flapping wing micro air vehicle

    NARCIS (Netherlands)

    Caetano, J.V.; Weehuizen, M.B.; De Visser, C.C.; De Croon, G.C.H.E.; Mulder, M.

    2015-01-01

    Several formulations have been proposed to model the dynamics of ornithopters, with inconclusive results regarding the need for complex kinematic formulations. Furthermore, the impact of assumptions made in the collected results was never assessed by comparing simulations with real flight data. In t

  20. Structure and kinematics of edge-on galaxy discs - IV. The kinematics of the stellar discs

    NARCIS (Netherlands)

    Kregel, M; van der Kruit, PC

    2005-01-01

    The stellar disc kinematics in a sample of 15 intermediate- to late-type edge-on spiral galaxies are studied using a dynamical modelling technique. The sample covers a substantial range in maximum rotation velocity and deprojected face-on surface brightness and contains seven spirals with either a b

  1. Structure and kinematics of edge-on galaxy discs - I. Observations of the stellar kinematics

    NARCIS (Netherlands)

    Kregel, M; van der Kruit, PC; Freeman, KC

    2004-01-01

    We present deep optical long-slit spectra of 17 edge-on spiral galaxies of intermediate to late morphological type, mostly parallel to their major axes and in a few cases parallel to the minor axes. The line-of-sight stellar kinematics are obtained from the stellar absorption lines using the improve

  2. Geometric deviation modeling by kinematic matrix based on Lagrangian coordinate

    Science.gov (United States)

    Liu, Weidong; Hu, Yueming; Liu, Yu; Dai, Wanyi

    2015-09-01

    Typical representation of dimension and geometric accuracy is limited to the self-representation of dimension and geometric deviation based on geometry variation thinking, yet the interactivity affection of geometric variation and gesture variation of multi-rigid body is not included. In this paper, a kinematic matrix model based on Lagrangian coordinate is introduced, with the purpose of unified model for geometric variation and gesture variation and their interactive and integrated analysis. Kinematic model with joint, local base and movable base is built. The ideal feature of functional geometry is treated as the base body; the fitting feature of functional geometry is treated as the adjacent movable body; the local base of the kinematic model is fixed onto the ideal geometry, and the movable base of the kinematic model is fixed onto the fitting geometry. Furthermore, the geometric deviation is treated as relative location or rotation variation between the movable base and the local base, and it's expressed by the Lagrangian coordinate. Moreover, kinematic matrix based on Lagrangian coordinate for different types of geometry tolerance zones is constructed, and total freedom for each kinematic model is discussed. Finally, the Lagrangian coordinate library, kinematic matrix library for geometric deviation modeling is illustrated, and an example of block and piston fits is introduced. Dimension and geometric tolerances of the shaft and hole fitting feature are constructed by kinematic matrix and Lagrangian coordinate, and the results indicate that the proposed kinematic matrix is capable and robust in dimension and geometric tolerances modeling.

  3. The Kinematics of Manipulators Built From Closed Planar Mechanisms

    CERN Document Server

    Slutski, Leonid; Angeles, Jorge

    1999-01-01

    The paper discusses the kinematics of manipulators builts of planar closed kinematic chains. A special kinematic scheme is extracted from the array of these mechanisms that looks the most promising for the creation of different types of robotic manipulators. The structural features of this manipulator determine a number of its original properties that essentially simplify its control. These features allow the main control problems to be effectively overcome by application of the simple kinematic problems. The workspace and singular configurations of a basic planar manipulator are studied. By using a graphic simulation method, motions of the designed mechanism are examined. A prototype of this mechanism was implemented to verify the proposed approach.

  4. Effect of two different kinesio taping techniques on knee kinematics and kinetics in young females

    OpenAIRE

    Guner, Senem; Alsancak, Serap; KOZ, Mitat

    2015-01-01

    [Purpose] The application of kinesio taping may improve strength and performance, inhibit and facilitate motor activity, and increase range of motion. The aim of this study was to compare the effects of kinesio taping facilitation and inhibition applications on spatiotemporal knee kinematics and kinetics during walking activity in healthy subjects. [Subjects and Methods] A three-dimensional quantitative gait evaluation was performed without tape and with, facilitation and inhibition kinesio t...

  5. About kinematics and hydrodynamics of spinning particles: some simple considerations

    Energy Technology Data Exchange (ETDEWEB)

    Recami, Erasmo; Rodrigues Junior, Waldyr A. [Universidade Estadual de Campinas, SP (Brazil). Dept. de Matematica Aplicada; Salesi, Giovanni [Universita Statale di Catania (Italy). Dipt. di Fisica

    1995-12-01

    In the first part (Sections 1 and 2) of this paper - starting from the Pauli current, in the ordinary tensorial language - we obtain the decomposition of the non-relativistic field velocity into two orthogonal parts: the classical part, that is the velocity w p/m of the center-of-mass (CM), and the so-called quantum part, that is, the velocity V of the motion in the CM frame (namely, the integral spin motion or Zitterbewegung). By inserting such a complete, composite expression of the velocity into the kinetic energy term of the non-relativistic classical (Newtonian) Lagrangian, we straightforwardly get the appearance of the so-called quantum potential associated, as it is know, with the Madelueng fluid. This result carries further evidence that the quantum behaviour of micro-systems can be a direct consequence of the fundamental existence of spin. In the second part (Sections 3 and 4), we fix our attention on the total velocity vector v vector w + vector V, being now necessary to pass to relativistic (classical) physics; and we show that the proper time entering the definition of the four-velocity v{sup {mu}} for spinning particles has to be the proper time {tau} of the CM frame. Inserting the correct Lorentz factor into the definition of v{sup {mu}} leads to completely new kinematical properties for v{sup 2}. The important constraint p{mu} v{sup {mu}} identically true for scalar particles, but just assumed a priori in all previous spinning particle theories, is herein derived in a self-consistent way. (author). 24 refs.

  6. Research on constraint-based virtual assembly technologies

    Institute of Scientific and Technical Information of China (English)

    YANG Rundang; WU Dianliang; FAN Xiumin; YAN Juanqi

    2007-01-01

    To realize a constraint-based virtual assembly operation,the unified representations of the assembly constraint,the equivalent relation between the constraint and the degree of freedom(DOF),and the movement DOF reduction in a virtual environment are proposed.Several algorithms about the constraint treatment are submitted.First,the automatic recognition algorithm based on the assembly relation is used to determine the position and orientation relation between two geometry elements of constraint whether they meet the given errors.Second,to satisfy the new constraint,according to the positing solving algorithm,the position and orientation of an active part are modified with minimal adjustment after the part has satisfied the affirmed constraints.Finally,the algorithm of movement navigation based on the generalized coordinate system is put forward,and the part movement is guided.These algorithms have been applied to the integrated virtual assembly environment(IVAE)system.Experiments have indicated that these algorithms have well supported constraint treatments in the IVAE and realized the closer combination of the virtual and the real assembly processes.

  7. Noble gas isotopic ratios from historical lavas and fumaroles at Mount Vesuvius (southern Italy): constraints for current and future volcanic activity

    Science.gov (United States)

    Tedesco, Dario; Nagao, Keisuke; Scarsi, Paolo

    1998-12-01

    Helium, neon and argon isotope ratios have been analysed from phenocrysts of eleven lava samples belonging to the last eruptive cycle of Mount Vesuvius (1631 until 1944). The phenocrysts separates include pyroxene ( N=10) and olivine ( N=1). All phenocryst samples show similarly low gas contents (He, Ne and Ar ˜10 -10 cm 3/g). 3He/ 4He ratios, 5.3-2.11 Ra, are generally low if compared to those typical of the MORB and those of the European Subcontinental Mantle (ESCM), respectively R/ Ra 8.5±1 and 6.0-6.5. A decreasing trend is found from 1631 to 1796, while a more homogeneous set of data is obtained for more recent eruptions, as evidenced by an average R/ Ra value of 2.85. Neon ratios ( 21Ne/ 22Ne and 20Ne/ 22Ne) strongly differ from those typically found on volcanoes and suggest that a crustal component has been added in the source region to Mt. Vesuvius magmas. Argon ratios ( 40Ar/ 36Ar and 38Ar/ 36Ar) have values similar to the atmosphere and are well correlated. The low 40Ar/ 36Ar ratio (max. 302) is, however, in the range of the 40Ar/ 36Ar ratios obtained from several lava samples at other Italian volcanoes and might be considered to have a deep origin. Two hypothesis have been discussed: (1) a deep argon-like-air source, due to subduction of air-rich sediments and/or (2) a preferential loss of Ar, in comparison to lighter noble gases, from silicic melts. Helium isotopic analysis of gas samples recently collected from crater and submarine fumaroles are similar to those of lavas belonging to the final part of this eruptive cycle. This result supports the idea that no new juvenile fluids from the source region have been injected into the magmatic reservoir during the 1631-1944 eruptive cycle and, more importantly, until 1993. Both sets of data help to understand the genesis of these fluids and to constrain the current activity of the volcano.

  8. Feeding kinematics of phyllomedusine tree frogs.

    Science.gov (United States)

    Gray, L A; Nishikawa, K C

    1995-02-01

    Previous studies have demonstrated that the phyllomedusine hylids possess highly protrusible tongues, a derived characteristic within the family Hylidae. In the present study, the kinematics of the feeding behavior of a phyllomedusine species, Pachymedusa dacnicolor, was analyzed using high-speed video (180 frames s-1). Its behavior was compared with that of Hyla cinerea, a species with a weakly protrusible tongue. P. dacnicolor exhibits a faster rate of tongue protraction, a longer gape cycle and more variable feeding kinematics than H. cinerea. In addition, the tongue is used in a unique 'fly-swatter' fashion, to pin the prey to the substratum as the frog completes the lunge. The rapid tongue protraction, extended gape cycle and fly-swatter action may have evolved in response to a diet of large, rapidly moving insects. In addition, several duration variables of the feeding cycle were greater for misses than for captures and drops, which suggests that sensory feedback rather than biomechanics controls gape cycle duration.

  9. Kinematics and Aerodynamics of Backward Flying Dragonflies

    Science.gov (United States)

    Bode-Oke, Ayodeji; Zeyghami, Samane; Dong, Haibo

    2015-11-01

    Highly maneuverable insects such as dragonflies have a wide range of flight capabilities; precise hovering, fast body reorientations, sideways flight and backward takeoff are only a few to mention. In this research, we closely examined the kinematics as well as aerodynamics of backward takeoff in dragonflies and compared them to those of forward takeoff. High speed videography and accurate 3D surface reconstruction techniques were employed to extract details of the wing and body motions as well as deformations during both flight modes. While the velocities of both forward and backward flights were similar, the body orientation as well as the wing kinematics showed large differences. Our results indicate that by tilting the stroke plane angle of the wings as well as changing the orientation of the body relative to the flight path, dragonflies control the direction of the flight like a helicopter. In addition, our detailed analysis of the flow in these flights shows important differences in the wake capture phenomena among these flight modes. This work is supported by NSF CBET-1313217.

  10. Kinematic criterion for breaking of shoaling waves

    Science.gov (United States)

    Liberzon, Dan; Itay, Uri

    2016-11-01

    Validity of a kinematic criterion for breaking of shoaling waves was examined experimentally. Results obtained by simultaneous measurements of water surface velocity by PTV and of the propagation velocity of a steep crest up to the point of breaking inception during shoaling will be reported. The experiments performed in a large wave tank examining breaking behavior of gentle spillers during shoaling on three different slopes suggest a validity of the recently proposed kinematic criterion. The breaking inception was found to occur when the horizontal velocity of the water surface on the steep (local steepness of 0.41-0.6) crest reaches a threshold value of 0.85-0.95 of that of the crest propagation. The exact moment and position of breaking inception detected using a Phase Time Method (PTM), characterizing a unique shape of the local frequency fluctuations at the inception. Future implementation of the PTM method for detection of breaking events in irregular wave fields will be discussed. Supported by German-Israeli Foundation for Scientific Research and Development (GIF) Grant #2019392.

  11. Dissecting new physics models through kinematic edges

    Science.gov (United States)

    Iyer, Abhishek M.; Maitra, Ushoshi

    2017-02-01

    Kinematic edges in the invariant mass distributions of different final state particles are typically a signal of new physics. In this work we propose a scenario wherein these edges could be utilized in discriminating between different classes of models. To this effect, we consider the resonant production of a heavy Higgs like resonance (H1) as a case study. Such states are a characteristic feature of many new physics scenarios beyond the standard model (SM). In the event of a discovery, it is essential to identify the true nature of the underlying theory. In this work we propose a channel, H1→t2t , where t2 is a vectorlike gauge singlet top-partner that decays into W b , Z t , h t . Invariant mass distributions constructed out of these final states are characterized by the presence of kinematic edges, which are unique to the topology under consideration. Further, since all the final state particles are SM states, the position in the edges of these invariant mass distributions can be used to exclusively determine the masses of the resonances. Observation of these features are meant to serve as a trigger, thereby mandating a more detailed analysis in a particular direction of parameter space. The absence of these edge like features, in the specific invariant mass distributions considered here, in minimal versions of supersymmetric models (MSSM) also serves as a harbinger of such non-MSSM-like scenarios.

  12. Evolutionary constraints or opportunities?

    Science.gov (United States)

    Sharov, Alexei A.

    2014-01-01

    Natural selection is traditionally viewed as a leading factor of evolution, whereas variation is assumed to be random and non-directional. Any order in variation is attributed to epigenetic or developmental constraints that can hinder the action of natural selection. In contrast I consider the positive role of epigenetic mechanisms in evolution because they provide organisms with opportunities for rapid adaptive change. Because the term “constraint” has negative connotations, I use the term “regulated variation” to emphasize the adaptive nature of phenotypic variation, which helps populations and species to survive and evolve in changing environments. The capacity to produce regulated variation is a phenotypic property, which is not described in the genome. Instead, the genome acts as a switchboard, where mostly random mutations switch “on” or “off” preexisting functional capacities of organism components. Thus, there are two channels of heredity: informational (genomic) and structure-functional (phenotypic). Functional capacities of organisms most likely emerged in a chain of modifications and combinations of more simple ancestral functions. The role of DNA has been to keep records of these changes (without describing the result) so that they can be reproduced in the following generations. Evolutionary opportunities include adjustments of individual functions, multitasking, connection between various components of an organism, and interaction between organisms. The adaptive nature of regulated variation can be explained by the differential success of lineages in macro-evolution. Lineages with more advantageous patterns of regulated variation are likely to produce more species and secure more resources (i.e., long-term lineage selection). PMID:24769155

  13. CONSTRAINT PROGRAMMING AND UNIVERSITY TIMETABLING

    Directory of Open Access Journals (Sweden)

    G.W. Groves

    2012-01-01

    Full Text Available

    ENGLISH ABSTRACT: The technology of Constraint Programming is rapidly becoming a popular alternative for solving large-scale industry problems. This paper provides an introduction to Constraint Programming and to Constraint Logic Programming (CLP, an enabler of constraint programming. The use of Constraint Logic Programming is demonstrated by describing a system developed for scheduling university timetables. Timetabling problems have a high degree of algorithmic complexity (they are usually NP-Complete, and share features with scheduling problems encountered in industry. The system allows the declaration of both hard requirements, which must always be satisfied, and soft constraints which need not be satisfied, though this would be an advantage.

    AFRIKAANSE OPSOMMING: Hierdie artikel beskryf ’n familie van probleem-oplossingstegnieke bekend as “Constraint Programming”, wat al hoe meer gebruik word om groot-skaalse industriële probleme op te los. Die nut van hierdie tegnieke word gedemonstreer deur die beskrywing van ’n skeduleringsisteem om die roosters vir ’n universiteit te genereer. Roosterskeduleringsprobleme is in praktiese gevalle NP-volledig en deel baie eienskappe met industriële skeduleringsprobleme. Die sisteem wat hier beskryf word maak gebruik van beide harde beperkings (wat altyd bevredig moet word en sagte beperkings (bevrediging hiervan is wel voordelig maar dit is opsioneel.

  14. Effective Constraints for Quantum Systems

    CERN Document Server

    Bojowald, Martin; Skirzewski, Aureliano; Tsobanjan, Artur

    2008-01-01

    An effective formalism for quantum constrained systems is presented which allows manageable derivations of solutions and observables, including a treatment of physical reality conditions without requiring full knowledge of the physical inner product. Instead of a state equation from a constraint operator, an infinite system of constraint functions on the quantum phase space of expectation values and moments of states is used. The examples of linear constraints as well as the free non-relativistic particle in parameterized form illustrate how standard problems of constrained systems can be dealt with in this framework.

  15. Human body parts tracking and kinematic features assessment based on RSSI and inertial sensor measurements.

    Science.gov (United States)

    Blumrosen, Gaddi; Luttwak, Ami

    2013-08-23

    Acquisition of patient kinematics in different environments plays an important role in the detection of risk situations such as fall detection in elderly patients, in rehabilitation of patients with injuries, and in the design of treatment plans for patients with neurological diseases. Received Signal Strength Indicator (RSSI) measurements in a Body Area Network (BAN), capture the signal power on a radio link. The main aim of this paper is to demonstrate the potential of utilizing RSSI measurements in assessment of human kinematic features, and to give methods to determine these features. RSSI measurements can be used for tracking different body parts' displacements on scales of a few centimeters, for classifying motion and gait patterns instead of inertial sensors, and to serve as an additional reference to other sensors, in particular inertial sensors. Criteria and analytical methods for body part tracking, kinematic motion feature extraction, and a Kalman filter model for aggregation of RSSI and inertial sensor were derived. The methods were verified by a set of experiments performed in an indoor environment. In the future, the use of RSSI measurements can help in continuous assessment of various kinematic features of patients during their daily life activities and enhance medical diagnosis accuracy with lower costs.

  16. A physiologically based hypothesis for learning proprioception and in approximating inverse kinematics.

    Science.gov (United States)

    Simkins, Matt

    2016-05-01

    A long-standing problem in muscle control is the "curse of dimensionality". In part, this problem relates to the fact that coordinated movement is only achieved through the simultaneous contraction and extension of multitude muscles to specific lengths. Couched in robotics terms, the problem includes the determination of forward and inverse kinematics. Of the many neurophysiological discoveries in cortex is the existence of position gradients. Geometrically, position gradients are described by planes in Euclidean space whereby neuronal activity increases as the hand approaches locations that lie in a plane. This work demonstrates that position gradients, when coupled with known physiology in the spinal cord, allows for a way to approximate proprioception (forward kinematics) and to specify muscle lengths for goal-directed postures (inverse kinematics). Moreover, position gradients provide a means to learn and adjust kinematics as animals learn to move and grow. This hypothesis is demonstrated using computer simulation of a human arm. Finally, experimental predictions are described that might confirm or falsify the hypothesis.

  17. A quantitative comparison of two kinematic protocols for lumbar segment motion during gait.

    Science.gov (United States)

    Kiernan, D; Malone, A; O'Brien, T; Simms, C K

    2015-02-01

    During gait analysis, motion of the lumbar region is tracked either by means of a 2-dimensional assessment with markers placed along the spine or a 3-dimensional assessment treating the lumbar region as a rigid segment. The rigid segment assumption is necessary for inverse dynamic calculations further up the kinematic chain. In the absence of a reference standard, the choice of model is mostly based on clinical experience. However, the potential exists for large differences in kinematic output if different protocols are used. The aim of this study was to determine the influence of using two 3-dimensional lumbar segment protocols on the resultant kinematic output during gait. The first protocol was a skin surface rigid protocol with markers placed across the lumbar region while the second consisted of a rigid cluster utilizing active markers applied over the 3rd lumbar vertebra. Data from both protocols were compared through simultaneous recording during gait. Overall variability was lower in 4 out of 6 measures for the skin surface protocol. Ensemble average graphs demonstrated similar mean profiles between protocols. However, Functional Limits of Agreement demonstrated only a poor to moderate agreement. This trend was confirmed with a poor to moderate waveform similarity (CMC range 0.29-0.71). This study demonstrates that the protocol used to track lumbar segment kinematics is an important consideration for clinical and research purposes. Greater variability recorded by the rigid cluster during lumbar rotation suggests the skin surface protocol may be more suited to studies where axial rotation is a consideration.

  18. Human Body Parts Tracking and Kinematic Features Assessment Based on RSSI and Inertial Sensor Measurements

    Directory of Open Access Journals (Sweden)

    Gaddi Blumrosen

    2013-08-01

    Full Text Available Acquisition of patient kinematics in different environments plays an important role in the detection of risk situations such as fall detection in elderly patients, in rehabilitation of patients with injuries, and in the design of treatment plans for patients with neurological diseases. Received Signal Strength Indicator (RSSI measurements in a Body Area Network (BAN, capture the signal power on a radio link. The main aim of this paper is to demonstrate the potential of utilizing RSSI measurements in assessment of human kinematic features, and to give methods to determine these features. RSSI measurements can be used for tracking different body parts’ displacements on scales of a few centimeters, for classifying motion and gait patterns instead of inertial sensors, and to serve as an additional reference to other sensors, in particular inertial sensors. Criteria and analytical methods for body part tracking, kinematic motion feature extraction, and a Kalman filter model for aggregation of RSSI and inertial sensor were derived. The methods were verified by a set of experiments performed in an indoor environment. In the future, the use of RSSI measurements can help in continuous assessment of various kinematic features of patients during their daily life activities and enhance medical diagnosis accuracy with lower costs.

  19. Age-related changes in kinematics of the knee joint during deep squat.

    Science.gov (United States)

    Fukagawa, Shingo; Leardini, Alberto; Callewaert, Barbara; Wong, Pius D; Labey, Luc; Desloovere, Kaat; Matsuda, Shuichi; Bellemans, Johan

    2012-06-01

    Researchers frequently use the deep knee squat as a motor task in order to evaluate the kinematic performance after total knee arthroplasty. Many authors reported about the kinematics of a normal squatting motion, however, little is known on what the influence of aging is. Twenty-two healthy volunteers in various age groups (range 21-75 years) performed a deep knee squat activity while undergoing motion analysis using an optical tracking system. The influence of aging was evaluated with respect to kinematics of the trunk, hip, knee and ankle joints. Older subjects required significantly more time to perform a deep squat, especially during the descending phase. They also had more knee abduction and delayed peak knee flexion. Older subjects were slower in descend than ascend during the squat. Although older subjects had a trend towards less maximal flexion and less internal rotation of the knee compared to younger subjects, this difference was not significant. Older subjects also showed a trend towards more forward leaning of the trunk, resulting in increased hip flexion and anterior thoracic tilt. This study confirmed that some aspects of squat kinematics vary significantly with age, and that the basic methodology employed here can successfully detect these age-related trends. Older subjects had more abduction of the knee joint, and this may indicate the load distribution of the medial and lateral condyles could be different amongst ages. Age-matched control data are therefore required whenever the performance of an implant is evaluated during a deep knee squat.

  20. 偏瘫患者与正常人日常生活活动的三维运动学分析%Three-dimensional kinematic analysis of the ability in the activities of daily living of hemiplegic patients and normal subjects

    Institute of Scientific and Technical Information of China (English)

    杨唐柱; 黄晓琳; 陈文斌; 熊蔡华; 孙容磊

    2010-01-01

    目的 采用三维运动学分析方法研究正常人和偏瘫患者在日常生活活动(ADL)中的上肢运动学特点.方法 应用Vcion运动捕捉系统(简称Vicon系统)采集15名正常人(健康组)和10例偏瘫患者(偏瘫组)在执行抬臂、梳头、喝水、摸对侧肩、摸后口袋这5项ADL时的上肢关节三维运动数据.经数据处理得到2组的胸锁关节、肩锁关节、肩关节、肘关节、腕关节的三维运动角度和各动作的运动时间,并进行比较.结果 偏瘫组胸锁关节旋外和外展角度,肩锁关节旋内和后伸角度,肘关节屈曲角度较健康组均显著增大,差异有统计学意义(P<0.05),而其肩锁关节内收角度,肩关节内收、外展、前屈、后伸、旋外和旋内角度较健康组则显著减小,差异有统计学意义(P<0.05);偏瘫组运动时间较健康组显著延长,差异有统计学意义(P<0.05).结论 初步建立了一种基于Vicon系统的上肢三维运动学分析方法,所得结果提示偏瘫患者采用与正常人不同的关节运动模式来完成ADL.%Objective To study the kinematic characteristics of normal subjects and hemiplegic patients in activities of daily living (ADL) by three-dimensional (3D) kinematic analysis. Methods A Vicon motion capture system was used to record 3D kinematic data on 15 normal subjects ( the healthy group) and 10 hemiparetic patients (the hemiplegic group) performing 5 ADL tasks: reaching up, combing, drinking, touching the opposite shoulder and touching the back pocket. The movement times and the 3D motion angles of the sternoclavicular joint,the acromioclavicular joint, the shoulder joint, the elbow joint and the wrist joint were recorded. Three-dimensional joint angles and movement times were compared between the normal group and the hemiplegic group. Results Compared with the normal group, the hemiplegic group had significantly more lateral rotation and abduction of the sternoclavicular joint, medial rotation and