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1

Inverse kinematics based on high-order moments of feature points and their Jacobian matrices  

Microsoft Academic Search

In this paper, we propose the inverse kinematics method based on high-order moment features and their Jaco- bian matrices, which can use an arbitrary information source about the shape of the targeted kinematic chain as reference input. The method is especially useful to generate the motion of humanoid robots and human figures, and we can generate the whole body pose

Ko Ayusawa; Yoshihiko Nakamura

2011-01-01

2

Development of the inverse Jacobian for the Kraft slave, and its use in force reflecting teleoperation  

NASA Astrophysics Data System (ADS)

The development of the symbolic inverse of a manipulator Jacobian and its use in controlling the manipulator is discussed. The ease of symbolically inverting a matrix is directly related to the simplicity of the expressions in the matrix. Therefore, a general method for obtaining a simplified form of the Jacobian of a manipulator in any of the intermediate link frames is developed and presented using an example. Also, a general method is presented for the verification of a manipulator Jacobian using the forward kinematics. A hand-waving discussion of the inversion of the Kraft slave Jacobian using symbolic manipulation software is given and the final form of the inverse is presented. An approximate solution to the inverse Jacobian problem for the Kraft slave using symbolic inverses is presented. This solution is used in dealing with the only reachable singularity of the Kraft slave. Finally, a teleoperational control system using the inverse Jacobian to calculate the inverse kinematics is discussed.

Schinstock, Dale E.; Faddis, Terry N.; Greenway, R. B.

1993-12-01

3

Inverse Jacobian Regulator With Gravity Compensation: Stability and Experiment  

Microsoft Academic Search

Task-space regulation of robot manipulators can be classified into two fundamental approaches, namely, transpose Jacobian regulation and inverse Jacobian regulation. In this paper, two inverse Jacobian regulators with gravity compensations are presented, and the stability problems are formulated and solved. It is shown that the inverse Jacobian systems can be stabilized, and there exists a region of attraction such that

Chien-Chern Cheah; Hwee Choo Liaw

2005-01-01

4

Robust Inverse Kinematics Using Damped Least Squares with Dynamic Weighting.  

National Technical Information Service (NTIS)

This paper presents a general method for calculating the inverse kinematics with singularity and joint limit robustness for both redundant and non-redundant serial-link manipulators. Damped least squares inverse of the Jacobian is used with dynamic weight...

D. E. Schinstock T. N. Faddis R. B. Greenway

1994-01-01

5

Real-Time Inverse Kinematics Techniques for Anthropomorphic Limbs  

Microsoft Academic Search

In this paper we develop a set of inverse kinematics algorithms suitable for an anthropomorphic arm or leg. We use a combination of analytical and numeri-cal methods to solve generalized inverse kinematics problems including position, orientation, and aiming constraints. Our combination of analytical and numerical methods results in faster and more reliable algorithms than conventional inverse Jacobian and optimization-based techniques.

Deepak Tolani; Ambarish Goswami; Norman I. Badler

2000-01-01

6

New insights into input relegation control for inverse kinematics of a redundant manipulator. Part 1, On the orthogonality of matrices B and J and comparison to the extended Jacobian method  

SciTech Connect

A method for kinematically modeling a constrained rigid body mechanical system and a method for controlling such a system termed input relegation control (IRC) were applied to resolve the kinematic redundancy of a serial link manipulator moving in an open chain configuration in. A set of equations was introduced to define a new vector variable parameterizing the redundant degrees of freedom (DOF) as a linear function of the joint velocities. The new set was combined with the classical kinematic velocity model of manipulator and solved to yield a well specified solution for the joint velocities as a function of the Cartesian velocities of the end effector and of the redundant DOF variable. In the previous work a technique was proposed for selecting the matrix relating the redundant DOF variable to the joint velocities which resulted in it rows being orthogonal to the rows of the Jacobian matrix. The implications for such a selection were not discussed in. In Part 1 of this report a basis for the joint space is suggested which provides considerable insight into why picking the aforementioned matrix to be orthogonal to the Jacobian is advantageous. A second objective of Part 1 is to compare the IRC method to the Extended Jacobian method of Baillieul and Martin and other related methods.

Unseren, M.A.; Reister, D.B.

1995-07-01

7

Inverse Kinematics for Humanoid Robots  

Microsoft Academic Search

Real-time control of the endeffector of a human- oid robot in external coordinates requires computationally efficient solutions of the inverse kinematics problem. In this context, this paper investigates methods of resolved motion rate control (RMRC) that employ optimization criteria to resolve kinematic redundancies. In particular we focus on two established techniques, the pseudo inverse with explicit optimization and the extended

Gaurav Tevatia; Stefan Schaal

2000-01-01

8

Review of the damped least-squares inverse kinematics with experiments on an industrial robot manipulator  

Microsoft Academic Search

The goal of this paper is to present experimental results on the implementation of the damped least-squares method for the six-joint ABB IRb2000 industrial robot manipulator. A number of inverse kinematics schemes are reviewed which allow robot control through kinematic singularities. The basic scheme adopts a damped least-squares inverse of the manipulator Jacobian with a varying damping factor acting in

S. Chiaverini; B. Siciliano; O. Egeland

1994-01-01

9

Style-based inverse kinematics  

Microsoft Academic Search

This paper presents an inverse kinematics system based on a learned model of human poses. Given a set of constraints, our system can produce the most likely pose satisfying those constraints, in real-time. Training the model on different input data leads to different styles of IK. The model is represented as a probability distribution over the space of all possible

Keith Grochow; Steven L. Martin; Aaron Hertzmann; Zoran Popovic

2004-01-01

10

Pseudo-inverse Jacobian control with grey relational analysis for robot manipulators mounted on oscillatory bases  

NASA Astrophysics Data System (ADS)

Interest in complex robotic systems is growing in new application areas. An example of such a robotic system is a dexterous manipulator mounted on an oscillatory base. In literature, such systems are known as macro/micro systems. This work proposes pseudo-inverse Jacobian feedback control laws and applies grey relational analysis for tuning outer-loop PID control parameters of Cartesian computed-torque control law for robotic manipulators mounted on oscillatory bases. The priority when modifying controller parameters should be the top ranking importance among parameters. Grey relational grade is utilized to investigate the sensitivity of tuning the auxiliary signal PID of the Cartesian computed-torque law to achieve desired performance. Results of this study can be feasible to numerous mechanical systems, such as mobile robots, gantry cranes, underwater robots, and other dynamic systems mounted on oscillatory bases, for moving the end-effector to a desired Cartesian position.

Lin, J.; Lin, C. C.; Lo, H.-S.

2009-10-01

11

The Inverse Kinematics of 3-D Towing  

Microsoft Academic Search

\\u000a This work addresses the kinematics of 3-D towing where multiple aerial robots are used to cooperatively transport a payload\\u000a using cables. In 3-D towing, it is important to determine the relative positions of the robots for the desired position and\\u000a orientation of the payload. This is actually the inverse kinematics problem of the 3-D towing. In the case with three

Qimi Jiang; Vijay Kumar

12

Wrist-Partitioned, Inverse Kinematic Accelerations and Manipulator Dynamics  

Microsoft Academic Search

An efficient algorithm is presented for the calculation of the inverse kinematic accelerations for a six-degree-of-freedom manipulator with a spherical wrist. The inverse kinematic calculation is shown to work synergistically with the inverse dynamic calculation, producing kinematic parameters needed in the recursive Newton-Euler dynamics formulation. Additional savings in the dynamic computation are noted for a class of kinematically well-structured manipulators,

John M. Hollerbach; Gideon Sahar

1983-01-01

13

Efficient calculation of Jacobian and adjoint vector products in the wave propagational inverse problem using automatic differentiation  

SciTech Connect

Wave propagational inverse problems arise in several applications including medical imaging and geophysical exploration. In these problems, one is interested in obtaining the parameters describing the medium from its response to excitations. The problems are characterized by their large size, and by the hyperbolic equation which models the physical phenomena. The inverse problems are often posed as a nonlinear data-fitting where the unknown parameters are found by minimizing the misfit between the predicted data and the actual data. In order to solve the problem numerically using a gradient-type approach, one must calculate the action of the Jacobian and its adjoint on a given vector. In this paper, the authors explore the use of automatic differentiation (AD) to develop codes that perform these calculations. They show that by exploiting structure at 2 scales, they can arrive at a very efficient code whose main components are produced by AD. In the first scale they exploit the time-stepping nature of the hyperbolic solver by using the Extended Jacobian framework. In the second (finer) scale, they exploit the finite difference stencil in order to make explicit use of the sparsity in the dependence of the output variables to the input variables. The main ideas in this work are illustrated with a simpler, one-dimensional version of the problem. Numerical results are given for both one- and two-dimensional problems. They present computational templates that can be used in conjunction with optimization packages to solve the inverse problem.

Coleman, T.F.; Santosa, F.; Verma, A.

2000-01-01

14

Inverse kinematics positioning using nonlinear programming for highly articulated figures  

Microsoft Academic Search

An articulated figure is often modeled as a set of rigid segments connected with joints. Its configuration can be altered by varying the joint angles. Although it is straight forward to compute figure configurations given joint angles (forward kinematics), it is more difficult to find the joint angles for a desired configuration (inverse kinematics). Since the inverse kinematics problem is

Jianmin Zhao; Norman I. Badler

1994-01-01

15

Directed Neutron Beams From Inverse Kinematic Reactions  

SciTech Connect

Kinematic focusing of an emitted fairly mono-energetic neutron beam by the use of inverse-kinematic reactions, i.e. where the projectile mass is greater than the target atom's mass, can provide for the utilization of a significant fraction of the fast neutron yield and also provide for a safer radiation environment. We examine the merit of various neutron production reactions and consider the practicalities of producing the primary beam using the suitable accelerator technologies. Preliminary progress at the NSWC-Carderock Positive Ion Accelerator Facility is described. Possible important applications for this type of neutron-based system can be both advanced medical imaging techniques and active ''stand-off'' interrogation of contraband items.

Vanhoy, J. R. [Department of Physics, 572C Holloway Road, US Naval Academy, Annapolis, MD 21402 (United States); Guardala, N. A. [Positive Ion Accelerator Facility, NSWC-Carderock Division, West Bethesda, MD 20817 (United States); Glass, G. A. [Louisiana Accelerator Center, Physics Department, University of Louisiana at Lafayette, Louisiana 70504 (United States)

2011-06-01

16

Real-Time Inverse Kinematics through Constrained Dynamics  

Microsoft Academic Search

Motion capture is an essential technique for interactive systems, such as distributed virtual reality, video games, and entertainment.\\u000a Inverse kinematics algorithms are often used to minimize the number of trackers required for motion capture systems. The solving\\u000a of inverse kinematics problems can be computationally expensive. We introduce a real-time algorithm for inverse kinematics\\u000a computation, originally from the field of molecular

Wen Tang; Marc Cavazza; Rae A. Earnshaw

1998-01-01

17

Nailing and Pinning: Adding Constraints to Inverse Kinematics  

Microsoft Academic Search

Inverse kinematics is commonly applied to compute the resulting movement of an avatar for a prescribed target pose. The motion path computed by inverse kinematics, however, often difiers from the expected or desired result due to an underconstrained parameter space of the degrees-of- freedom of all joints. In such cases, it is necessary to introduce additional constraints, for instance by

Mardé Greeff; Jörg Haber; Hans-peter Seidel

2005-01-01

18

A GENERAL ALGORITHM FOR THE INVERSE TRANSFORMATION OF MAP PROJECTIONS USING JACOBIAN MATRICES  

Microsoft Academic Search

Coordinate transformations refer to mathematical processing that enables overlay of maps that use different coordinate reference systems, that is, map projections. The conversion from geographical to plane coordinates is the normal practice in cartography, which is called forward transformation. The inverse transformation, which yields geographical coordinates from map coordinates, is a more recent development, due to the need for transformation

Cengizhan Ipbüker; I. Öztug Bildirici

2002-01-01

19

A motion planning based approach for inverse kinematics of redundant robots: the kinematic roadmap  

Microsoft Academic Search

We propose a new approach to solving the point-to-point inverse kinematics problem for highly redundant manipulators. It is inspired by recent motion planning research and explicitly takes into account constraints due to joint limits and self-collisions. Central to our approach is the novel notion of kinematic roadmap for a manipulator. The kinematic roadmap captures the connectivity of the configuration space

Juan Manuel Ahuactzin; K. Gupta

1997-01-01

20

Inferring the resolution of source kinematic inversions: a blind test  

NASA Astrophysics Data System (ADS)

Kinematic inversions of near-fault data allow to retrieve certain properties of earthquake rupture, such as the slip distribution, the rupture velocity and the slip rate which depends on the choice of the source time function. Accurate images of the spatio-temporal rupture process are also a necessary ingredient to move from kinematic source characterizations to reliable models of the dynamic fracture process. Several techniques have been developed in the past to carry out such source inversions, with an apparent increase in estimated rupture complexity which also reflects the increasing amount and quality of near-fault strong-motion data. However, the resolution, reliability and quality of these finite-source rupture models still remains an open question. Particular choices in the inversion method (fault parametrization, selection and processing of data, minimum search alogrithm and fitness function) influence the inversion results, leading to different and sometimes incompatible slip maps for the same earthquake. We therefore construct a blind test inversion exercise in which several research groups attempt to derive a kinematic rupture model from synthetic seismograms calculated for an input model unknown to the people performing the inversion. During several stages of this blind test, we increase the complexity of the input model while also the "data quality" will be decreased by adding random noise to the synthetic seismograms. The major aim of this study is to compare different source-imaging techniques, to understand their strengths and weaknesses and to check the processing of data. Besides inferring the general properties of the rupture, we will also be able to asses the resolution and possibly uncertainties in the model parameters, which will furnish guide lines and directions for future work. The test is carried out in the framework of the EU-SPICE project (Seismic wave Propagation and Imaging in Complex media - a European project), but is also open to other interested researchers.

Festa, G.; Mai, P. M.; Francois-Holden, C.; Burjanek, J.; di Carli, S.; Emolo, A.; Gallovic, F.; Zollo, A.; Delouis, B.; Madariaga, R.

2005-12-01

21

Stretched knee walking with novel inverse kinematics for humanoid robots  

Microsoft Academic Search

A four degrees of freedom (DoF) waist and trunk mechanism, as well as human-like foot, enable the humanoid robot WABIAN-2R to perform human-like walk with stretched knees, and heel-contact and toe-off gait phases. The inverse kinematics (IK) method, used in the present system, requires specification of not only task space reference trajectories, but also reference trajectories for all redundant DoFs.

Przemyslaw Kryczka; Kenji Hashimoto; Hideki Kondo; Aiman Omer; Hun-ok Lim; Atsuo Takanishi

2011-01-01

22

An inverse kinematics approach to hexapod design and control  

NASA Astrophysics Data System (ADS)

Hexapod platforms have found use in high-end systems when precision positioning and multiple degrees of freedom are required. Hexapods make use of parallel kinematics to achieve these high levels of precision and accuracy and can often outperform traditional methods. Traditional methods generally involve serial kinematics in the form of stacked translation and rotation stages. They have the advantage of being conceptually simple and straightforward to implement, but often suffer from decreased stability. Despite the advantages of stability and the freedom of motion hexapods offer, hexapods are often avoided because of their non-intuitive nature. Inverse kinematics can be used to determine the interaction between the motions of the individual linear actuators and the motion of the mobile platform of a hexapod. We endeavor to present a straightforward approach to understanding hexapod movements and provide insight into the advantages and limitations of hexapod platforms. This paper presents concepts that can be utilized by the designer or user to determine fundamentals such as resolution, motion limits, actuator loading, and stiffness of a given hexapod design.

Dewitt, Frank A., IV

2009-08-01

23

Efficient Calculation of Jacobian and Adjoint Vector Products in the Wave Propagational Inverse Problem Using Automatic Differentiation  

Microsoft Academic Search

Wave propagational inverse problems arise in several applications including medical imaging and geophysical exploration. In these problems, one is interested in obtaining the parameters describing the medium from its response to excitations. The problems are characterized by their large size, and by the hyperbolic equation which models the physical phenomena. The inverse problems are often posed as a nonlinear data-fitting

Thomas F. Coleman; Fadil Santosa; Arun Verma

2000-01-01

24

Coulomb excitation of radioactive nuclear beams in inverse kinematics  

SciTech Connect

Techniques for the measurement of B (E2:0{sub 1}{sup +} {r_arrow} 2{sub 1}{sup +}) values by Coulomb excitation of Radioactive Nuclear Beams in inverse kinematics are described. Using a thin, low Z target, the Coulomb excited beam nuclei will decay in flight downstream of the target. For long lifetimes (nanosecond range) these nuclei decay centimeters downstream of the target and for shorter lifetimes (picoseconds or less) they decay near the target. Corresponding to these two lifetime regimes two methods have been developed to measure {gamma} rays from the Coulomb excited nuclei: the lifetime method in which the lifetime of the excited state is deduced from the decay curve and the integral method in which the B(E2) value is extracted from the measured total Coulomb excitation cross section.

Zamfir, N.V. [Brookhaven National Lab., Upton, NY (United States)]|[Yale Univ., New Haven, CT (United States)]|[Clark Univ., Worcester, MA (United States)]|[Inst. of Atomic Physics, Bucharest Magurele (Romania); Barton, C.J.; Brenner, D.S. [Clark Univ., Worcester, MA (United States); Casten, R.F. [Brookhaven National Lab., Upton, NY (United States)]|[Yale Univ., New Haven, CT (United States); Gill, R.L. [Brookhaven National Lab., Upton, NY (United States); Zilges, A. [Yale Univ., New Haven, CT (United States)]|[Univ. zu Koeln (Germany). Inst. fuer Kernphysik

1996-12-31

25

Combining analytical inverse kinematics with example postures to generate virtual human whole body reaching postures  

Microsoft Academic Search

To ensure the real-time interactivity and the lifelikeness, analytical inverse kinematics and the example posture library are adopted to generate whole body reaching postures. The upper limb joint angles are solved using analytical inverse kinematics and optimization. First, a new objective function to minimize the wrist joint angles is presented and the optimized swivel angel is calculated with directed searching

Shilei Li; Jiahong Liang; Guang Liu; Yong Zhang

2008-01-01

26

Algebraic-elimination based solution of inverse kinematics for a humanoid robot finger  

Microsoft Academic Search

The inverse kinematics is a challenging problem for controlling a humanoid robot finger with nonlinearly coupled joints. In this paper, a novel approach is proposed to derive the algebraic-elimination based solutions of inverse kinematics (IK) for the robot fingers. First, the given position of the fingertip is transformed from the base frame to the solution frames by means of D-H

Ming-Tzong Lin; Hong-Bo Lin; Chung-Ching Liu; Ying-Lung Lin; Che-Hau Wu; Cheng-Wei Tung

2011-01-01

27

Bipedal robot walking strategy on inclined surfaces using position and orientation based inverse kinematics algorithm  

Microsoft Academic Search

This paper proposes a strategy for bipedal robot walking on inclined surfaces using position and orientation based inverse kinematics algorithm. Some researchers implemented control approaches to solve bipedal walking on inclined surfaces. Generally, most of them apply control feedback at ankle joints and also introduced many more control methodologies. In this paper, inverse kinematics methodology is introduced systematically for bipedal

Fariz Ali; Aliza Che Amran; Atsuo Kawamura

2010-01-01

28

Cortical network modeling for inverse kinematic computation of an anthropomorphic finger  

Microsoft Academic Search

The performance of reaching movements to visual targets requires complex kinematic mechanisms such as redundant, multijointed, anthropomorphic actuators and thus is a difficult problem since the relationship between sensory and motor coordinates is highly nonlinear. In this article, we present a neural model able to learn the inverse kinematics of a simulated anthropomorphic robot finger (ShadowHand™ finger) having four degrees

Rodolphe J. Gentili; Hyuk Oh; Javier Molina; Jose L. Contreras-Vidal

2011-01-01

29

Joint coseismic and postseismic kinematic slip inversions in a Bayesian framework (Invited)  

NASA Astrophysics Data System (ADS)

The classic linear, kinematic, static slip inversion of geodetic data requires specification of a smoothing norm of slip parameters, a residual norm of the data, and a choice about the relative weight between the two norms and the relative weights of multiple data sets. Inversions for unknown fault geometry are nonlinear and therefore the fault geometry is often assumed to be known for the slip inversion problem. We present Bayesian, probabilistic inversion methods to invert simultaneously for fault slip and fault geometry and relative data weighting assuming a uniform stress drop over the slipping area of the fault. The method produces the posterior probability distribution of stress drop, fault geometry parameters, fault slip, and data weights. We apply the method to 2003 Cheng Kung, Taiwan earthquake, the 2010 Jiashian, Taiwan earthquake, and the 2004 Parkfield, California earthquake and compare with conventional slip slip inversion results. In each case, the conventional slip inversions and the uniform stress drop inversions produce overly smooth slip distributions because of the inherently poor resolution of slip at depth in static, kinematic inversions. We show that the resolution of coseismic slip can be improved by jointly inverting coseismic and postseismic displacements. We do this joint inversion assuming a uniform stress drop for the coseismic rupture and a full release of coseismic shear stress increase on the fault to compute the cumulative postseismic displacements. The joint inversion is conducted in the same probabilistic framework as the coseismic uniform stress drop inversion. In the case of the 2004 Parkfield and 2003 Cheng Kung earthquakes, the joint inversion results in more compact slip distributions and higher coseismic stress drops than the coseismic-only slip inversion.

Johnson, K. M.; Fukuda, J.; Sun, J.

2010-12-01

30

3D Motion Planning Algorithms for Steerable Needles Using Inverse Kinematics  

PubMed Central

Steerable needles can be used in medical applications to reach targets behind sensitive or impenetrable areas. The kinematics of a steerable needle are nonholonomic and, in 2D, equivalent to a Dubins car with constant radius of curvature. In 3D, the needle can be interpreted as an airplane with constant speed and pitch rate, zero yaw, and controllable roll angle. We present a constant-time motion planning algorithm for steerable needles based on explicit geometric inverse kinematics similar to the classic Paden-Kahan subproblems. Reachability and path competitivity are analyzed using analytic comparisons with shortest path solutions for the Dubins car (for 2D) and numerical simulations (for 3D). We also present an algorithm for local path adaptation using null-space results from redundant manipulator theory. Finally, we discuss several ways to use and extend the inverse kinematics solution to generate needle paths that avoid obstacles.

Duindam, Vincent; Xu, Jijie; Alterovitz, Ron; Sastry, Shankar; Goldberg, Ken

2010-01-01

31

An inverse kinematics architecture enforcing an arbitrary number of strict priority levels  

Microsoft Academic Search

An efficient Inverse Kinematics solver is a key element in applications targeting the on-line or off-line postural control of complex articulated figures. In the present paper we progressively describe the strategic components of a very general and robust IK architecture. We then present an efficient recursive algorithm enforcing an arbitrary number of strict priorities to arbitrate the fulfillment of conflicting

Paolo Baerlocher; Ronan Boulic

2004-01-01

32

Kinematic Source Parameters for the 1989 Loma Prieta Earthquake from the Nonlinear Inversion of Accelerograms  

Microsoft Academic Search

We describe a technique to infer the kinematic parameters of the earth- quake rupture process by the nonlinear inversion of near-source high-frequency seis- mic records. The model assumes that each point on the fault plane slips, when the rupture front passes, with a variable slip amplitude. For a given rupture model syn- thetic seismograms are computed by using the ray

Antonio Emolo; Aldo Zollo

2005-01-01

33

Inverse kinematics with floating base and constraints for full body humanoid robot control  

Microsoft Academic Search

This paper explores inverse kinematics for full body, floating base, task space control on a real humanoid robot. We discuss how constraints can be used to address the issue of under-actuation due to floating base, and list the sufficient conditions for maintaining task space control of arbitrary robot tasks. We suggest a controller based on a task priority framework and

M. Mistry; J. Nakanishi; G. Cheng; S. Schaal

2008-01-01

34

Slope-walking of a biped robot with position and orientation based inverse kinematics method  

Microsoft Academic Search

This paper proposes a slope-walking strategy of a bipedal robot using position and orientation based inverse kinematics method. Some researchers implemented control approaches to solve this problem. Generally, they apply control feedback at ankle joints and introduced many more control methodologies. Several researchers used pelvis and foot trajectories without showing center of mass trajectory. In this paper, a constant center

Fariz Ali; Aliza Che Amran; Atsuo Kawamura

2010-01-01

35

Cortical network modeling for inverse kinematic computation of an anthropomorphic finger.  

PubMed

The performance of reaching movements to visual targets requires complex kinematic mechanisms such as redundant, multijointed, anthropomorphic actuators and thus is a difficult problem since the relationship between sensory and motor coordinates is highly nonlinear. In this article, we present a neural model able to learn the inverse kinematics of a simulated anthropomorphic robot finger (ShadowHand™ finger) having four degrees of freedom while performing 3D reaching movements. The results revealed that this neural model was able to control accurately and robustly the finger when performing single 3D reaching movements as well as more complex patterns of motion while generating kinematics comparable to those observed in human. The long term goal of this research is to design a bio-mimetic controller providing adaptive, robust and flexible control of dexterous robotic/prosthetics hands. PMID:22256258

Gentili, Rodolphe J; Oh, Hyuk; Molina, Javier; Contreras-Vidal, José L

2011-01-01

36

Neutron capture surrogate reaction on 75As in inverse kinematics using (d,p )  

SciTech Connect

The 75As(d,p ) reaction in inverse kinematics as a surrogate for neutron capture was performed at Oak Ridge National Laboratory using a deuterated plastic target. The intensity of the 165 keV -ray from 76As in coincidence with ejected protons, from exciting 76As above the neutron separation energy populating a compound state, was measured. A tight geometry of four segmented germanium clover -ray detectors together with eight ORRUBA-type silicon-strip charged-particle detectors were used to optimize geometric acceptance. The preliminary analysis of the 75As experiment and the ecacy and future plans of the (d,p ) surrogate campaign in inverse kinematics are discussed.

Peters, W. A. [Rutgers University; Cizewski, J. A. [Rutgers University; Hatarik, Robert [Rutgers University; O'Malley, Patrick [Rutgers University; Jones, K. L. [University of Tennessee; Schmitt, Kyle [University of Tennessee; Moazen, Brian [University of Tennessee; Chae, K. Y. [University of Tennessee; Pittman, S. T. [University of Tennessee, Knoxville (UTK); Kozub, R. L. [Tennessee Technological University; Vieira, D. J. [Los Alamos National Laboratory (LANL); Jandel, M. [Los Alamos National Laboratory (LANL); Wilhelmy, J. B. [Los Alamos National Laboratory (LANL); Matei, Catalin [Oak Ridge Associated Universities (ORAU); Escher, J. [Lawrence Livermore National Laboratory (LLNL); Bardayan, Daniel W [ORNL; Pain, Steven D [ORNL; Smith, Michael Scott [ORNL

2010-01-01

37

Cortex inspired model for inverse kinematics computation for a humanoid robotic finger.  

PubMed

In order to approach human hand performance levels, artificial anthropomorphic hands/fingers have increasingly incorporated human biomechanical features. However, the performance of finger reaching movements to visual targets involving the complex kinematics of multi-jointed, anthropomorphic actuators is a difficult problem. This is because the relationship between sensory and motor coordinates is highly nonlinear, and also often includes mechanical coupling of the two last joints. Recently, we developed a cortical model that learns the inverse kinematics of a simulated anthropomorphic finger. Here, we expand this previous work by assessing if this cortical model is able to learn the inverse kinematics for an actual anthropomorphic humanoid finger having its two last joints coupled and controlled by pneumatic muscles. The findings revealed that single 3D reaching movements, as well as more complex patterns of motion of the humanoid finger, were accurately and robustly performed by this cortical model while producing kinematics comparable to those of humans. This work contributes to the development of a bioinspired controller providing adaptive, robust and flexible control of dexterous robotic and prosthetic hands. PMID:23366569

Gentili, Rodolphe J; Oh, Hyuk; Molina, Javier; Reggia, James A; Contreras-Vidal, José L

2012-01-01

38

Cortex Inspired Model for Inverse Kinematics Computation for a Humanoid Robotic Finger  

PubMed Central

In order to approach human hand performance levels, artificial anthropomorphic hands/fingers have increasingly incorporated human biomechanical features. However, the performance of finger reaching movements to visual targets involving the complex kinematics of multi-jointed, anthropomorphic actuators is a difficult problem. This is because the relationship between sensory and motor coordinates is highly nonlinear, and also often includes mechanical coupling of the two last joints. Recently, we developed a cortical model that learns the inverse kinematics of a simulated anthropomorphic finger. Here, we expand this previous work by assessing if this cortical model is able to learn the inverse kinematics for an actual anthropomorphic humanoid finger having its two last joints coupled and controlled by pneumatic muscles. The findings revealed that single 3D reaching movements, as well as more complex patterns of motion of the humanoid finger, were accurately and robustly performed by this cortical model while producing kinematics comparable to those of humans. This work contributes to the development of a bioinspired controller providing adaptive, robust and flexible control of dexterous robotic and prosthetic hands.

Gentili, Rodolphe J.; Oh, Hyuk; Molina, Javier; Reggia, James A.; Contreras-Vidal, Jose L.

2013-01-01

39

Combining Reinforcement Learning and Differential Inverse Kinematics for Collision-Free Motion of Multilink Manipulators  

Microsoft Academic Search

This paper presents a class of neural controllers that learn goal-oriented obstacle-avoiding strategies for multilink manipulators. They acquire these strategies on-line through reinforcement learning from local sensory data. These controllers are mainly made of two neural modules: a reinforcement-based action generator and a module for differential inverse kinematics (DIV). The action generator generates actions with regard to a goal vector

Pedro Martín; José Del R. Millán

1997-01-01

40

Inverse kinematics analysis for the arm of a mobile humanoid robot based on the closed-loop algorithm  

Microsoft Academic Search

This paper presents a kind of method for the inverse kinematics of a seven degrees of freedom (DoF) arm installed on a mobile humanoid robot. Due to the redundancy of 7-DoF open-chain arm, the closed-loop inverse kinematics via pseudoinverse method is used to solve the corresponding joint trajectories if the end-effector trajectory is given. Because of the existence of the

Jingguo Wang; Yangmin Li

2009-01-01

41

Analysis of ^26Al + p elastic and inelastic scattering reactions in inverse kinematics at the HRIBF  

NASA Astrophysics Data System (ADS)

It is unknown to what degree novae contribute to the abundance of ^26Al in the Galaxy. Destruction through the ^26Al(p,?)^27Si reaction may reduce the nova contribution, but uncertainties in the properties of ^27Si levels above the proton threshold limit reaction rate estimates. Inelastic proton scattering in these environments may also reduce the net production of ^26Al. To constrain estimates of the degree of ^26Al destruction in novae, the ^26Al + p elastic and inelastic reactions were investigated in inverse kinematics (Ec.m.= 0.5-1.5 MeV) at the HRIBF. The experiment and results of the analysis will be discussed.

Pittman, S. T.; Chae, K. Y.; Jones, K. L.; Moazen, B. H.; Bardayan, D. W.; Nesaraja, C. D.; Pain, S. D.; Smith, M. S.; Chipps, K. A.; Kozub, R. L.; Shriner, J. F., Jr.; Matei, C.; Matos, M.; O'Malley, P. D.; Peters, W. A.; Parker, P. D.

2009-10-01

42

Vortices and Jacobian varieties  

NASA Astrophysics Data System (ADS)

We investigate the geometry of the moduli space of N vortices on line bundles over a closed Riemann surface ? of genus g>1, in the little explored situation where 1?NJacobian variety of ?. For N=1, we show that the metric on the moduli space converges to a natural Bergman metric on ?. When N>1, the vortex metric typically degenerates as the dissolving limit is approached, the degeneration occurring precisely on the critical locus of the Abel-Jacobi map of ? at degree N. We describe consequences of this phenomenon from the point of view of multivortex dynamics.

Manton, Nicholas S.; Romão, Nuno M.

2011-06-01

43

Integrated Analytic and Linearized Inverse Kinematics for Precise Full Body Interactions  

NASA Astrophysics Data System (ADS)

Despite the large success of games grounded on movement-based interactions the current state of full body motion capture technologies still prevents the exploitation of precise interactions with complex environments. This paper focuses on ensuring a precise spatial correspondence between the user and the avatar. We build upon our past effort in human postural control with a Prioritized Inverse Kinematics framework. One of its key advantage is to ease the dynamic combination of postural and collision avoidance constraints. However its reliance on a linearized approximation of the problem makes it vulnerable to the well-known full extension singularity of the limbs. In such context the tracking performance is reduced and/or less believable intermediate postural solutions are produced. We address this issue by introducing a new type of analytic constraint that smoothly integrates within the prioritized Inverse Kinematics framework. The paper first recalls the background of full body 3D interactions and the advantages and drawbacks of the linearized IK solution. Then the Flexion-EXTension constraint (FLEXT in short) is introduced for the partial position control of limb-like articulated structures. Comparative results illustrate the interest of this new type of integrated analytical and linearized IK control.

Boulic, Ronan; Raunhardt, Daniel

44

Creation of Thin Deuterated Polyethylene Targets for Inverse Kinematics Transfer Reaction Measurements  

NASA Astrophysics Data System (ADS)

Transfer reactions are an important tool for the study of single-particle structure of nuclei. Such measurements have many applications to the field of astrophysics, such as study of the rapid neutron capture (r-) process that is believed to create heavy elements in supernovae. Measurements in inverse kinematics are necessary when studying transfer reactions on unstable nuclei with lifetimes too short to be used as targets. The measurement of deuteron-induced transfer reactions in inverse kinematics requires a target containing a significant quantity of deuterons, such as deuterated polyethylene ((C2D4)n or CD2), which can be fabricated into thin foils by dissolving CD2 in xylene. A campaign is underway at ORNL to measure (d,p) reactions with unique heavy fission fragment beams. For such measurements, thin targets are favored to minimize peak broadening in the energy spectra of emitted particles. Emphasis has been placed on creation of targets of ˜70 ?g/cm^2 thickness, significantly thinner than previously used at ORNL. Improvements, such as careful control of the temperature of slides covered by the CD2/xylene solution, have been developed to produce such targets. Details will be presented. This research is supported by the Office of Nuclear Physics in the U. S. Department of Energy.

Long, K. D.; Kozub, R. L.; Manning, B.; Pain, S. D.; Nesaraja, C. D.; Smith, M. S.; Bardayan, D. W.

2011-10-01

45

Alpha-particle capture reactions in inverse kinematics relevant to p-process nucleosynthesis  

NASA Astrophysics Data System (ADS)

The first feasibility study of an ?-particle capture reaction in inverse kinematics at energies relevant to the p process was performed at the Wien Filter of the LISE spectrometer at GANIL. Hereby, the 4He(78Kr,?)82Sr reaction was investigated using as target an 4He-implanted thin Al foil. The analysis of the data has shown that the determination of (?,?) reaction cross sections at rather low energies around 2 MeV/u in inverse kinematics is indeed feasible regarding the high rejection rate of the primary beam, which in the present work was better than a factor of 109. However, the expected position of the recoils of interest was completely masked by particles of currently unknown origin that could hardly be attributed to scattering of the primary beam. The most probable explanation for the origin of these ``pollutants'' could be microscopic dust particles of 10 ?m diameter and less, that are extremely difficult to avoid in standard experimental conditions. Hence, the use of a gas-jet target instead of a solid one is compulsory.

Uji?, P.; Lagoyannis, A.; Mertzimekis, T. J.; de Oliveira Santos, F.; Harissopulos, S.; Demetriou, P.; Perrot, L.; Stodel, Ch.; Saint-Laurent, M.-G.; Kamalou, O.; Lefebvre-Schuhl, A.; Spyrou, A.; Amthor, M. A.; Grevy, S.; Caceres, L.; Koivisto, H.; Laitinen, M.; Uusitalo, J.; Julin, R.

2011-10-01

46

Minor actinide fission induced by multi-nucleon transfer reaction in inverse kinematics  

NASA Astrophysics Data System (ADS)

In the framework of nuclear waste incineration and design of new generation nuclear reactors, experimental data on fission probabilities and on fission fragment yields of minor actinides are crucial to design prototypes. Transfer-induced fission has proven to be an efficient method to study fission probabilities of actinides which cannot be investigated with standard techniques due to their high radioactivity. We report on the preliminary results of an experiment performed at GANIL that investigates fission probabilities with multi-nucleon transfer reactions in inverse kinematics between a 238U beam on a 12C target. Actinides from U to Cm were produced with an excitation energy range from 0 to 30 MeV. In addition, inverse kinematics allowed to characterize the fission fragments in mass and charge. A key point of the analysis resides in the identification of the actinides produced in the different transfer channels. The new annular telescope SPIDER was used to tag the target-like recoil nucleus of the transfer reaction and to determine the excitation energy of the actinide. The fission probability for each transfer channel is accessible and the preliminary results for 238U are promising.

Derkx, X.; Rejmund, F.; Caamaño, M.; Schmidt, K.-H.; Audouin, L.; Bacri, C.-O.; Barreau, G.; Benlliure, J.; Casarejos, E.; Fernández-Domínguez, B.; Gaudefroy, L.; Golabek, C.; Jurado, B.; Lemasson, A.; Navin, A.; Rejmund, M.; Roger, T.; Shrivastava, A.; Schmitt, C.; Taieb, J.

2010-03-01

47

Evaluating the effect of network density and geometric distribution on kinematic source inversion models  

NASA Astrophysics Data System (ADS)

An essential element of understanding earthquake source processes is obtaining a reliable source model via geophysical data inversion. The most common procedure to determine the kinematic source parameters (final slip, peak slip velocity, rise time and rupture time) is to invert observed ground motions recorded at a number of different stations (typically strong motion accelerometers). Few studies have been dedicated to evaluate the effect of the number of stations and their geometrical distribution on earthquake source parameters. In this paper we investigate these effects by inverting ground motions from synthetic dynamic earthquake rupture models with heterogeneous stress distribution governed by the slip weakening friction law. Our first target model is a buried strike-slip event (Mw 6.5) in a layered half space. The Compsyn code (Spudich and Xu, 2002) was used in the inversion procedure to generate forward synthetic waveforms, and an Evolutionary Algorithm was used to search for the source parameters: peak slip velocity (PSV), rupture time, and rise time at low frequency (up to 1Hz). The regularized Yoffe function was applied as a single window slip velocity function, which is a flexible slip velocity function defined by three independent parameters: the final slip, the slip duration and the duration of the positive slip acceleration, Tacc (Tinti, et al. 2005). The same velocity structure was used for both the foward and inversion modeling and no noise was added to the synthetic ground motions before inversion. We applied the Tikhonov regularization to smooth the final slip on fault, which is controlled by PSV and rise time. Our preliminary results show that: First, we can capture large slip patches of the dynamic models with good ground velocity waveform fitting, using the regularized Yoffe function, which is consistent with the overall properties of dynamic rupture models. Second, the geometry of station distribution is important for finite kinematic source inversion. The number of stations affects the variation of source image, but a surprisingly small number of well-spaced stations appears sufficient to obtain a stable solution in our study. We obtained a relatively good source model even using only one station given a certain azimuthal and distance between source and station, though we note this is in the unrealistic case of perfect knowledge of ground motions (no noise, tilting), velocity structure, and fault geometry, etc.. However, even with these 'perfect' conditions, and using unrealistically large numbers of stations optimally distributed around the fault, the details of slip velocity complexities resulted from the dynamic rupture models are not well captured by the inversion procedure.

Zhang, Youbing; Song, Seok Goo; Dalguer, Luis; Clinton, John

2013-04-01

48

Solving the inverse kinematics problem symbolically by means of knowledge-based and linear algebra-based methods  

Microsoft Academic Search

The construction of kinematics models by hand is often a tedious and error-prone process. This paper presents an overview of the Organic Robot Control project. One main goal of the project is to automate the computation of closed-formed solutions for both the forward and inverse kinematics of general industrial manipulators. For simple manipulator geometries, we use rule-based programming techniques to

Michael Wenz; Heinz Wörn

2007-01-01

49

14Be(p,n)14B reaction at 69 MeV in inverse kinematics  

NASA Astrophysics Data System (ADS)

A Gamow-Teller (GT) transition from the drip-line nucleus 14Be to 14B was studied via the (p,n) reaction in inverse kinematics using a secondary 14Be beam at 69 MeV/nucleon. The invariant mass method is employed to reconstruct the energy spectrum. A peak is observed at an excitation energy of 1.27(2) MeV in 14B, together with bumps at 2.08 and 4.06(5) MeV. The observed forward peaking of the state at 1.27 MeV and a good description for the differential cross section, obtained with a DWBA calculation provide support for the 1+ assignment to this state. By extrapolating the cross section to zero momentum transfer the GT-transition strength is deduced. The value is found to compare well with that reported in a ?-delayed neutron emission study.

Satou, Y.; Nakamura, T.; Kondo, Y.; Matsui, N.; Hashimoto, Y.; Nakabayashi, T.; Okumura, T.; Shinohara, M.; Fukuda, N.; Sugimoto, T.; Otsu, H.; Togano, Y.; Motobayashi, T.; Sakurai, H.; Yanagisawa, Y.; Aoi, N.; Takeuchi, S.; Gomi, T.; Ishihara, M.; Kawai, S.; Ong, H. J.; Onishi, T. K.; Shimoura, S.; Tamaki, M.; Kobayashi, T.; Matsuda, Y.; Endo, N.; Kitayama, M.

2011-03-01

50

Optimization methods for hyper-redundant robots' inverse kinematics in biomedical applications  

NASA Astrophysics Data System (ADS)

The present work describes and compares several approaches applied to compute the inverse kinematics of a ten degrees of freedom hyper-redundant robot. The proposed approaches are based on an exhaustive method and several error-optimization algorithms. The algorithms' performance was evaluated based on two criteria: computational processing time and final actuator positioning error. The results obtained show that for a small number of modules (less or equal to four), the exhaustive method provides the best problem solution: acceptable computational processing time as well as minimum error. However, for larger number of modules, the error-optimization approach has far better performance regarding the error to processing time ratio. The mentioned hyper-redundant robot was projected to be used in biomedical applications.

Espinoza, Mario Sáenz; Pereira, Ana I.; Gonçalves, José

2012-09-01

51

Gravity modeling: the Jacobian function and its approximation  

NASA Astrophysics Data System (ADS)

In mathematics, the elements of a Jacobian matrix are the first-order partial derivatives of a scalar function or a vector function with respect to another vector. In inversion theory of geophysics the elements of a Jacobian matrix are a measure of the change of the output signal caused by a local perturbation of a parameter of a given (Earth) model. The elements of a Jacobian matrix can be determined from the general Jacobian function. In gravity modeling this function consists of the "geometrical part" (related to the relative location in 3D of a field point with respect to the source element) and the "source-strength part" (related to the change of mass density of the source element). The explicit (functional) expressions for the Jacobian function can be quite complicated and depend both on the coordinates used (Cartesian, spherical, ellipsoidal) and on the mathematical parametrization of the source (e.g. the homogenous rectangular prism). In practice, and irrespective of the exact expression for the Jacobian function, its value on a computer will always be rounded to a finite number of digits. In fact, in using the exact formulas such finite representation may cause numerical instabilities. If the Jacobian function is smooth enough, it is an advantage to approximate it by a simpler function, e.g. a piecewise-polynomial, which numerically is more robust than the exact formulas and which is more suitable for the subsequent integration. In our contribution we include a whole family of the Jacobian functions which are associated with all the partial derivatives of the gravitational potential of order 0 to 2, i.e. including all the elements of the gravity gradient tensor. The quality of the support points for the subsequent polynomial approximation of the Jacobian function is ensured by using the exact prism formulas in quadruple precision. We will show some first results. Also, we will discuss how such approximated Jacobian functions can be used for large scale modeling so that the source model can (almost) be of unlimited degree of detail and where the modeling can be conducted without a substantial increase in the computational task. The main idea here is to integrate instead of summing up the partial contributions from the discrete source elements.

Strykowski, G.; Lauritsen, N. L. B.

2012-04-01

52

Humanlike motion of a humanoid robot arm based on a closed-form solution of the inverse kinematics problem  

Microsoft Academic Search

Humanoid robotics is a new challenging field. To cooperate with human beings, humanoid robots not only have to feature human-like form and structure but, more importantly, they must possess human-like characteristics regarding motion, communication and intelligence. In this paper, we propose an algorithm for solving the inverse kinematics problem associated with the redundant robot arm of the humanoid robot ARMAR.

T. Asfour; R. Dillmann

2003-01-01

53

Efficient calculation of sparse Jacobians  

SciTech Connect

This paper describes a new approach for efficient Jacobian calculation using automatic differentiation. This approach obviates the need for vector accumulation by reducing certain parts of the computational graph representing the system of equations, allowing the Jacobian to be accumulated through a series of scalar operations. The advantages of this new approach include low spatial complexity, the ability to adapt to available memory if resources are limited, the ability to efficiently handle linear equations in a convenient manner, and low computational complexity. In addition, this approach is particularly well suited for evaluations within an interpretive environment. The approach can be applied to both the forward and reverse modes of automatic differentiation.

Tolsma, J.E.; Barton, P.I.

1999-07-01

54

Derivation of three closed loop kinematic velocity models using normalized quaternion feedback for an autonomous redundant manipulator with application to inverse kinematics  

SciTech Connect

The report discusses the orientation tracking control problem for a kinematically redundant, autonomous manipulator moving in a three dimensional workspace. The orientation error is derived using the normalized quaternion error method of Ickes, the Luh, Walker, and Paul error method, and a method suggested here utilizing the Rodrigues parameters, all of which are expressed in terms of normalized quaternions. The analytical time derivatives of the orientation errors are determined. The latter, along with the translational velocity error, form a dosed loop kinematic velocity model of the manipulator using normalized quaternion and translational position feedback. An analysis of the singularities associated with expressing the models in a form suitable for solving the inverse kinematics problem is given. Two redundancy resolution algorithms originally developed using an open loop kinematic velocity model of the manipulator are extended to properly take into account the orientation tracking control problem. This report furnishes the necessary mathematical framework required prior to experimental implementation of the orientation tracking control schemes on the seven axis CESARm research manipulator or on the seven-axis Robotics Research K1207i dexterous manipulator, the latter of which is to be delivered to the Oak Ridge National Laboratory in 1993.

Unseren, M.A.

1993-04-01

55

Compactified Jacobians and Torelli map  

Microsoft Academic Search

Abstract. We compare,several constructions of compactified jacobians - us- ing semistable sheaves, semistable projective curves, degenerations of abelian varieties, and combinatorics of cell decompositions - and show that they are equivalent. We give a detailed description of the ”canonical compactified ja- cobian” in degree g ¡ 1. Finally, we explain how Kapranov’s compactification of configuration spaces can be understood as

Valery Alexeev

2004-01-01

56

Study of 13B(d,p)14B Reaction in Inverse Kinematics with Helios  

NASA Astrophysics Data System (ADS)

The ^14B nucleus was studied employing the (d, p) reaction in inverse kinematics using HELIOS at the ATLAS facility at ANL. A beam of ^13B with energy 15.7 MeV/nucleon was produced using the In-Flight method. Protons from the ^13B(d, p)^14B reaction were detected and analyzed using the HELIOS device. Detecting and identifying the recoiling ^13B and ^14B nuclei in a silicon ?E-E telescope at forward angles distinguished bound and unbound states in ^14B. Angular-momentum transfers and relative spectroscopic factors were deduced for the four lowest states in ^14B. The ground and first excited states, 2^- and 1^- respectively, are presumably made up of ?(0p3/2)-?(1s1/2) configurations, while coupling of the proton hole to a d5/2 neutron produces (1,2,3,4)^-. The 0d5/2-1s1/2 splitting in ^14B is expected to be small, producing mixing between the (1,2)^- l = 0 and 2 configurations. The measured spectroscopic factors for neutron transfer will be compared to the predictions of the shell model calculations.

Bedoor, S.; Wuosmaa, A. H.; Lighthall, J. C.; Marley, S. T.; Shetty, D. V.; Alcorta, M.; Back, B. B.; Bertone, P. F.; Rehm, K. E.; Rogers, A. M.; Schiffer, J. P.; Brown, B. A.; Deibel, C. M.

2012-10-01

57

LENDA: A low energy neutron detector array for experiments with radioactive beams in inverse kinematics  

NASA Astrophysics Data System (ADS)

The Low Energy Neutron Detector Array (LENDA) is a neutron time-of-flight (TOF) spectrometer developed at the National Superconducting Cyclotron Laboratory (NSCL) for use in inverse kinematics experiments with rare isotope beams. Its design has been motivated by the need to study the spin-isospin response of unstable nuclei using (p,n) charge-exchange reactions at intermediate energies (>100MeV/u). It can be used, however, for any reaction study that involves emission of low energy neutrons (150 keV to 10 MeV). The array consists of 24 plastic scintillator bars and is capable of registering the recoiling neutron energy and angle with high detection efficiency. The neutron energy is determined by the time-of-flight technique, while the position of interaction is deduced using the timing and energy information from the two photomultipliers of each bar. A simple test setup utilizing radioactive sources has been used to characterize the array. Results of test measurements are compared with simulations. A neutron energy threshold of <150keV, an intrinsic time (position) resolution of ˜ 400 ps (˜ 6 cm) and an efficiency >20% for neutrons below 4 MeV have been obtained.

Perdikakis, G.; Sasano, M.; Austin, Sam M.; Bazin, D.; Caesar, C.; Cannon, S.; Deaven, J. M.; Doster, H. J.; Guess, C. J.; Hitt, G. W.; Marks, J.; Meharchand, R.; Nguyen, D. T.; Peterman, D.; Prinke, A.; Scott, M.; Shimbara, Y.; Thorne, K.; Valdez, L.; Zegers, R. G. T.

2012-09-01

58

Real time evaluation of inverse kinematics for a 3RPS medical parallel robot usind dSpace platform  

Microsoft Academic Search

The paper addresses the analysis of three methods for inverse kinematics of a 3-DOF medical parallel robot with R-P-S (Revolute-Prismatic-Spherical) joint structure using MATLAB\\/Simulink and dSpace platform. The three methods were implemented in MATLAB\\/Simulink and than exported to dSpace realtime development platform. A comparation between the times of these three methods has been studyed. The scope of this paper is

Ciprian-Radu Rad; Milos Manic; R. Ba?lan; S.-D. Stan

2010-01-01

59

The Structure of \\mathcal{H}_s-OPTIMAL Solutions of the Inverse Kinematic Problem of Diffraction from Polycrystalline Objects  

NASA Astrophysics Data System (ADS)

The author continues the study of the inverse kinematic problem of diffraction from polycrystalline objects in Sobolev spaces of automorphic functions on the three-dimensional rotation group. An effective intrinsic description is obtained for the orthogonal complement of the subspace of common zeros of a finite family of diffraction operators. Based on this description, a projection method is proposed for constructing an \\mathcal{H}_s-optimal solution of the diffraction problem with incomplete data.Bibliography: 7 titles.

Yashnikov, V. P.

1984-02-01

60

Hyperelliptic Curves and Their Jacobians  

Microsoft Academic Search

\\u000a The theory of algebraic curves and their Jacobians is a vast subject with a long history and huge applications. In this chapter,\\u000a we are going to present only some basic notions and facts, as necessary for further use. Balancing a reasonable length of\\u000a an introductory chapter and the wish to provide a self-contained exposition, we refer the reader to [GH1978b,Mum1983,Dub1981,Gun1966

Vladimir Dragovi?; Milena Radnovi?

61

Estimating periodic organ motions based on inverse kinematics using tetrahedron mesh registration  

NASA Astrophysics Data System (ADS)

Minimally/Non-invasive surgery has become increasingly widespread because of its therapeutic benefits such as less pain, less scarring, and shorter hospital stay. However, it is very difficult to eliminate the target cancer cells selectively without damaging nearby normal tissues and vessels since the tumors inside organs cannot be visually tracked in realtime with the existing imaging devices while organs are deformed by respiration and surgical instruments. Note that realtime 2D US imaging is widely used for monitoring the minimally invasive surgery such as Radiofrequency ablation; however, it is difficult to detect target tumors except high-echogenic regions because of its noisy and limited field of view. To handle these difficulties, we present a novel framework for estimating organ motion and deformed shape during respiration from the available features of 2D US images, by means of inverse kinematics utilizing 3D CT volumes at the inhale and exhale phases. First, we generate surface meshes of the target organ and tumor as well as centerlines of vessels at the two extreme phases considering surface correspondence. Then, the corresponding tetrahedron meshes are generated by coupling the internal components for volumetric modeling. Finally, a deformed organ mesh at an arbitrary phase is generated from the 2D US feature points for estimating the organ deformation and tumor position. To show effectiveness of the proposed method, the CT scans from real patient has been tested for estimating the motion and deformation of the liver. The experimental result shows that the average errors are less than 3mm in terms of tumor position as well as the whole surface shape.

Kang, Nahyup; Kim, Ji-Yeon; Kim, Kyung Hwan; Lee, Hyong-Euk; Kim, James D. K.

2013-03-01

62

Studies Of Neutron-Rich Nuclei With (d,p) Reactions In Inverse Kinematics At The HRIBF  

SciTech Connect

Two N=51 isotones have been measured using (d,p) reactions in inverse kinematics at the Holifield Radioactive Beam Facility (HRIBF) of Oak Ridge National Laboratory. Additionally, we have performed a test measurement using a stable 124Sn beam in preparation for measurements of the 2H(130,132Sn,p)131,133Sn reactions. Preliminary results for 83Ge and 85Se suggest a 5/2+ ground state and a 1/2+ first excited state for both isotopes, in agreement with systematics for the N=51 isotones. The excitation energy of the first excited state is shown to drop as the proton number is reduced. Proton angular distributions following the 2H(124Sn,p)125Sn reaction show sensitivity to the l-value of the transfered nucleon and spectroscopic factors are in agreement with previous measurements in normal kinematics.

Jones, K.L.; Cizewski, J.A.; Thomas, J.S. [Department of Physics and Astronomy, Rutgers University, New Brunswick, NJ 08903 (United States); Baktash, C.; Bardayan, D.W.; Blackmon, J.C.; Gross, C.J.; Liang, J.F.; Shapira, D.; Smith, M.S. [Physics Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Catford, W.N. [Department of Physics, University of Surrey, Guildford, Surrey, GU2 7XH (United Kingdom); Fitzgerald, R.P.; Visser, D. [Department of Physics and Astronomy, University of NC, Chapel Hill, NC 27599 (United States); Greife, U.; Livesay, R.J. [Department of Physics, Colorado School of Mines, Golden, CO 80401 (United States); Johnson, M.S. [Oak Ridge Associated Universities, Oak Ridge, PO Box 117, TN 37831 (United States); Kozub, R.L.; Moazen, B.H.; Nesaraja, C.D. [Physics Department, Tennessee Technological University, Cookeville, TN 38505 (United States); Ma, Z. [Physics Department, University of Tennessee, Knoxville, TN 37996 (United States)

2005-04-05

63

Testing inverse kinematic models of paleocrustal thickness in extensional systems with high-resolution forward thermo-mechanical models  

NASA Astrophysics Data System (ADS)

Reconstructing continental paleocrustal thickness is important for estimating tectonic accommodation, constraining three-dimensional basin geometry during early rifting phases of extensional margins and predicting the distribution of thick crustal sills that may block the global ocean and create restricted basins. We test an inverse kinematic method for modeling paleocrustal thickness by inverting the final bulk crustal structure produced from high-resolution thermo-mechanical models of lithospheric extension. The inverse kinematic method assumes pure shear, includes simple rules based on geodynamic models and field observations and requires displacement boundary conditions and the prescription of a transition from rigid to nonrigid deformation. The inverse pure-shear method produces a history of bulk crustal thickness that closely matches the forward models provided that the width of the rift zone is narrow during the later phases of continental extension when crust undergoes hyper-extension. We also observe that the width and surface trace of large-scale (LS) shear zones observed in the thermo-mechanical models coincide with inflection points and large gradients in inverted nonrigid velocity field. Our results demonstrate that if displacement boundary conditions can be constrained and the transition from rigid to nonrigid deformation defines a narrow rift zone during hyper-extension then relatively simple kinematic rules can be used to invert present-day bulk crustal structure for paleocrustal thickness, bulk lateral strain and aspects of upper crustal shear zone geometry from extensional systems with nonlinear rheology, structures dominated by simple shear in the upper crust, depth-dependent extension and asymmetric crustal thinning.

Kneller, Erik A.; Albertz, Markus; Karner, Garry D.; Johnson, Christopher A.

2013-07-01

64

Polynomial Automorphisms and the Jacobian Conjecture  

Microsoft Academic Search

In this paper we give an update survey of the most important results concerning the Jacobian conjecture: several equivalent descriptions are given and various related conjectures are discussed. At the end of the paper, we discuss the recent counter-examples, in all dimensions greater than two, to the Markus-Yamabe conjecture (Global asymptotic Jacobian conjecture). Résumé Dans ce papier nous présentons un

Arno van den ESSEN

65

Extraction of human gait signatures: an inverse kinematic approach using Groebner basis theory applied to gait cycle analysis  

NASA Astrophysics Data System (ADS)

This research highlights the results obtained from applying the method of inverse kinematics, using Groebner basis theory, to the human gait cycle to extract and identify lower extremity gait signatures. The increased threat from suicide bombers and the force protection issues of today have motivated a team at Air Force Institute of Technology (AFIT) to research pattern recognition in the human gait cycle. The purpose of this research is to identify gait signatures of human subjects and distinguish between subjects carrying a load to those subjects without a load. These signatures were investigated via a model of the lower extremities based on motion capture observations, in particular, foot placement and the joint angles for subjects affected by carrying extra load on the body. The human gait cycle was captured and analyzed using a developed toolkit consisting of an inverse kinematic motion model of the lower extremity and a graphical user interface. Hip, knee, and ankle angles were analyzed to identify gait angle variance and range of motion. Female subjects exhibited the most knee angle variance and produced a proportional correlation between knee flexion and load carriage.

Barki, Anum; Kendricks, Kimberly; Tuttle, Ronald F.; Bunker, David J.; Borel, Christoph C.

2013-05-01

66

Closed-form inverse kinematics for intra-operative mobile C-arm positioning with six degrees of freedom  

NASA Astrophysics Data System (ADS)

For trauma and orthopedic surgery, maneuvering a mobile C-arm X-ray device into a desired position in order to acquire the right picture is a routine task. The precision and ease of use of the C-arm positioning becomes even more important for more advanced imaging techniques as parallax-free X-ray image stitching, for example. Standard mobile C-arms have only five degrees of freedom (DOF), which definitely restricts their motions that have six DOF in 3D Cartesian space. We have proposed a method to model the kinematics of the mobile Carm and operating table as an integrated 6DOF C-arm X-ray imaging system.1 This enables mobile C-arms to be positioned relative to the patient's table with six DOF in 3D Cartesian space. Moving mobile C-arms to a desired position and orientation requires finding the necessary joint values, which is an inverse kinematics problem. In this paper, we present closed-form solutions, i.e. analytic expressions, obtained in an algebraic way for the inverse kinematics problem of the 6DOF C-arm model. In addition, we implement a 6DOF C-arm system for interactively radiation-free C-arm positioning based on a continuous guidance from C-arm pose estimation. For this we employ a visual marker pattern attached under the operating table and a mobile C-arm system augmented by a video camera and mirror construction. In our experiment, repositioning C-arm to a pre-defined pose in a phantom study demonstrates the practicality and accuracy of our developed 6DOF C-arm system.

Wang, Lejing; Zou, Rui; Weidert, Simon; Landes, Juergen; Euler, Ekkehard; Burschka, Darius; Navab, Nassir

2011-03-01

67

An improved inverse kinematic and velocity solution for spatial hyper-redundant robots  

Microsoft Academic Search

A new and efficient kinematic position and velocity solution scheme for spatial hyper-redundant manipulators is presented. The manipulator's arm has discrete links and universal joints. Backbone curve concepts and a modal approach are used to resolve the manipulator's redundancy. The effects of the mode shapes and the slope of the backbone curve at the starting point on the workspace are

Farbod Fahimi; Hashem Ashrafiuon; Chandrasekhar Nataraj

2002-01-01

68

3D Motion Planning Algorithms for Steerable Needles Using Inverse Kinematics  

Microsoft Academic Search

Steerable needles can be used in medical applica- tions to reach targets behind sensitive or impenetrable areas. The kinematics of a steerable needle are nonholonomic and, in 2D, equivalent to a Dubins car with constant radius of curvature. In 3D, the needle can be interpreted as an airplane with constant speed and pitch rate, zero yaw, and controllable roll angle.

Vincent Duindam; Jijie Xu; Ron Alterovitz; Shankar Sastry; Kenneth Y. Goldberg

2008-01-01

69

The kinematic determinants of anuran swimming performance: an inverse and forward dynamics approach.  

PubMed

The aims of this study were to explore the hydrodynamic mechanism of Xenopus laevis swimming and to describe how hind limb kinematics shift to control swimming performance. Kinematics of the joints, feet and body were obtained from high speed video of X. laevis frogs (N=4) during swimming over a range of speeds. A blade element approach was used to estimate thrust produced by both translational and rotational components of foot velocity. Peak thrust from the feet ranged from 0.09 to 0.69 N across speeds ranging from 0.28 to 1.2 m s(-1). Among 23 swimming strokes, net thrust impulse from rotational foot motion was significantly higher than net translational thrust impulse, ranging from 6.1 to 29.3 N ms, compared with a range of -7.0 to 4.1 N ms from foot translation. Additionally, X. laevis kinematics were used as a basis for a forward dynamic anuran swimming model. Input joint kinematics were modulated to independently vary the magnitudes of foot translational and rotational velocity. Simulations predicted that maximum swimming velocity (among all of the kinematics patterns tested) requires that maximal translational and maximal rotational foot velocity act in phase. However, consistent with experimental kinematics, translational and rotational motion contributed unequally to total thrust. The simulation powered purely by foot translation reached a lower peak stroke velocity than the pure rotational case (0.38 vs 0.54 m s(-1)). In all simulations, thrust from the foot was positive for the first half of the power stroke, but negative for the second half. Pure translational foot motion caused greater negative thrust (70% of peak positive thrust) compared with pure rotational simulation (35% peak positive thrust) suggesting that translational motion is propulsive only in the early stages of joint extension. Later in the power stroke, thrust produced by foot rotation overcomes negative thrust (due to translation). Hydrodynamic analysis from X. laevis as well as forward dynamics give insight into the differential roles of translational and rotational foot motion in the aquatic propulsion of anurans, providing a mechanistic link between joint kinematics and swimming performance. PMID:18805818

Richards, Christopher T

2008-10-01

70

Geometry and kinematics of Late Cretaceous inversion structures in the Jiuquan Basin, western China  

USGS Publications Warehouse

Late Cretaceous inversion structures, which are significant for oil and gas accumulation, are widely distributed throughout the Jiuquan Basin. These structures are primarily made up of inverted faults and fault-related folds. Most of the axial planes of folds are parallel to inverted faults trending north-east, indicating that the principal stress direction was north-west - south-east in the Late Cretaceous. The average inversion ratios of faults in the four sags that were investigated are 0.39, 0.29, 0.38, 0.32. The average inversion ratio in the Jiuquan Basin is 0.34 and the degree of inversion is moderate to strong. As moderate inversion is suitable for forming excellent hydrocarbon traps, there is considered to be significant potential in the basin for the presence of structural traps. ?? 2005 Elsevier Ltd. All rights reserved.

Wang, B.; Chen, H.; Yang, S.; Xiao, A.; Cheng, X.; Rupp, J. A.

2005-01-01

71

Experimental study of the {sup 56}Ni({sup 3}He,d){sup 57}Cu reaction in inverse kinematics  

SciTech Connect

Measurements of ({sup 3}He,d) reactions can provide information on the proton widths of states that play a role in astrophysically important (p,{gamma}) reactions. We report on the first study of the ({sup 3}He,d) reaction in inverse kinematics with a {sup 56}Ni (T{sub 1/2}=6.1 d) ion beam. The Q-value resolution of {approx} keV achieved in this experiment was sufficient to separate the transitions populating the ground state and the 1/2{sup -}-5/2{sup -} doublet at E{sub x}{approx}1.1 MeV in {sup 57}Cu. Prospects for similar ({sup 3}He,d) experiments with improved energy resolution are also discussed.

Jiang, C. L.; Rehm, K. E.; Ackermann, D.; Ahmad, I.; Greene, J. P.; Harss, B.; Henderson, D.; Henning, W. F.; Janssens, R. V. F.; Nolen, J.; Pardo, R. C.; Reiter, P.; Schiffer, J. P.; Seweryniak, D.; Sonzogni, A.; Uusitalo, J.; Wiedenhoever, I.; Wuosmaa, A. H.; Brumwell, F.; McMichael, G. [Physics Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); IPNS, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Hebrew University, Jerusalem 90914 (Israel); Physics Department, Northwestern University, Evanston, Illinois 60201 (United States)] (and others)

2009-10-15

72

Isotopic yield distributions of transfer- and fusion-induced fission from 238U+12C reactions in inverse kinematics  

NASA Astrophysics Data System (ADS)

A method to access the complete identification in atomic number Z and mass A of fragments produced in low-energy fission of actinides is presented. This method, based on the use of multinucleon transfer and fusion reactions in inverse kinematics, is applied in this work to reactions between a 238U beam and a 12C target to produce and induce fission of moderately excited actinides. The fission fragments are detected and fully identified with the VAMOS spectrometer of GANIL, allowing the measurement of fragment yields of several hundreds of isotopes in a range between A˜80 and ˜160, and from Z˜30 to ˜64. Complete isotopic yield distributions of fragments from well defined fissioning systems are made available. Together with the precise measurement of the fragment emission angles and velocities, this technique gives further insight into the nuclear-fission process.

Caamaño, M.; Delaune, O.; Farget, F.; Derkx, X.; Schmidt, K.-H.; Audouin, L.; Bacri, C.-O.; Barreau, G.; Benlliure, J.; Casarejos, E.; Chbihi, A.; Fernández-Domínguez, B.; Gaudefroy, L.; Golabek, C.; Jurado, B.; Lemasson, A.; Navin, A.; Rejmund, M.; Roger, T.; Shrivastava, A.; Schmitt, C.

2013-08-01

73

The Inverse Kinematics Thick Target scattering method as a tool to study cluster states in exotic nuclei  

NASA Astrophysics Data System (ADS)

The inverse kinematics thick target scattering method (TTIK) was used to measure the 8Li resonant elastic scattering on a 4He target in order to investigate 8Li-? cluster configurations in excited states of 12B. A 8Li beam at Ebeam = 30.6 MeV, provided by the radioactive beam facility EXCYT of LNS in Catania, while passing through a thick Helium target decreases continuously its energy. Thus, elastic scattering can be induced starting from the initial beam energy down to zero. Time of flight measurement between beam particles passing through a MCP detector and ?-particles impinging on the ?E stage of a Si telescope detector allows the discrimination of elastic scattering from nuclear reaction events, thus representing an improvement of the TTIK method. In this paper the used experimental technique and preliminary results will be described.

Di Pietro, A.; Torresi, D.; Zadro, M.; Cosentino, L.; Ducoin, C.; Figuera, P.; Fisichella, M.; Lattuada, M.; Maiolino, C.; Musumarra, A.; Papa, M.; Pellegriti, M. G.; Rovituso, M.; Santonocito, D.; Scalia, G.; Scuderi, V.; Strano, E.

2012-05-01

74

Spectroscopy of {sup 16}O Using {alpha}+{sup 12}C Resonant Scattering in Inverse Kinematics  

SciTech Connect

A measurement of the {alpha}({sup 12}C,{alpha}){sup 12}C reaction has been performed using resonant scattering with a gas target. Beam energies of 46, 51, 56 and 63 MeV were used to populate resonances in the excitation energy range of 11.6 to 22.9 MeV in {sup 16}O. The angular distributions of the elastic scattering were measured at zero degrees using an array of segmented silicon strip detectors with a minimum range of 0 deg. to 30 deg. in the centre of mass. The spins of 8 resonances between 14.1 and 18.5 MeV were obtained, confirming spin assignments made using elastic scattering in normal kinematics. An R-matrix analysis of the data was performed which indicates that the present understanding of {sup 16}O in this region is good, but not complete.

Ashwood, N. I.; Freer, M.; Bloxham, T. R.; Curtis, N.; Haigh, P. J.; Price, D. L. [School of Physics and Astronomy, University of Birmingham, Edgbaston, Birmingham, B15 2TT (United Kingdom); Achouri, N. L. [LPC, ISMRA and Universite de Caen, IN2P3 CNRS, 14050 Caen Cedex (France); Catford, W. N.; Harlin, C. W.; Patterson, N. P.; Thomas, J. S. [School of Electronics and Physical Sciences, University of Surrey, Guildford, Surrey, GU2 7XH (United Kingdom); Soic, N. [Rudjer Boskovic Institut, Bijenicka 54, HR-1000, Zagreb (Croatia)

2009-08-26

75

Earthquake source kinematics of moderate earthquakes from the inversion of apparent source time functions  

NASA Astrophysics Data System (ADS)

We present an approach to infer the slip and rupture velocity distributions on the fault plane from the non-linear inversion of the apparent source time functions, obtained from the empirical Green's function deconvolution method. The main advantage of this technique is that it allows overcoming, in the forward modelling, the limitations related to the computation of the Green's function, as the choice of a correct and reliable earth propagation model. We perform a parameter resolution and uncertainty study, which is based on the analysis of the misfit function in the neighbourhood of the best-fitting model. In this paper, we present the results obtained by applying the technique to synthetic and real records from an Mw 4 event which occurred during the 2009 L'Aquila (central Italy) aftershock sequence. Results show a heterogeneous slip distribution, characterized by two main high slip patches located NW of the hypocentre and an average slip of 3.7 cm, corresponding to a seismic model of about 0.82 × 1015 Nm.

Serra, Eugenio Maria Toraldo; Emolo, Antonio; Orefice, Antonella; Zollo, Aldo

2013-08-01

76

Coulomb excitation of the 2{sub ms}{sup +} state of {sup 96}Ru in inverse kinematics  

SciTech Connect

We identify the J{sup {pi}}=2{sub 3}{sup +} state of {sup 96}Ru as the proton-neutron mixed-symmetry 2{sub ms}{sup +} state of this nucleus. This identification is based on the measurement of the transition strengths B(M1,2{sub 3}{sup +}{yields}2{sub 1}{sup +})=0.78(23) {mu}{sub N}{sup 2} and B(E2;2{sub 3}{sup +}{yields}0{sub 1}{sup +})=1.6(3) W.u. These transition strengths were obtained from the Coulomb excitation yield for the population of the 2{sub 3}{sup +} state relative to the yield of the 2{sub 1}{sup +} state with known E2 excitation strength. The Coulomb excitation was done in inverse kinematics using the reaction {sup nat}C({sup 96}Ru,{sup 96}Ru{sup (small star, filled)}) at 280 MeV. This work demonstrates the accessibility of the isovector quadrupole excitation in the valence shell using experiments with an accelerated beam of the nuclei of interest.

Pietralla, N.; Barton, C. J.; Kruecken, R.; Beausang, C. W.; Caprio, M. A.; Casten, R. F.; Cooper, J. R.; Hecht, A. A.; Newman, H.; Novak, J. R. (and others)

2001-09-01

77

Investigating the postseismic deformation of the 2010 Maule Chile megathrust; insights from kinematic inversions  

NASA Astrophysics Data System (ADS)

In the years following great earthquakes, surface deformation around the rupture area occurs at high and variable rates. Rapidly decaying (lasting for days or years) postseismic deformation in the near-field of the rupture may result from fault afterslip caused by the frictional response of the subduction interface to the coseismic stress perturbation. The spatio-temporal evolution of the rapidly decaying deformation has, so far, been difficult to determine based on available observations and present knowledge of the afterslip and related mechanisms. The 2010 Maule earthquake (Mw8.8) that affected about 500 km of the Nazca-South America plate boundary in south-central Chile was the first great and presumably gap-filling event to be captured by modern space-geodetical monitoring networks. The density of GPS coverage (both campaign and continuous daily solutions) alongside the rupture zone of the Maule event provides an excellent opportunity to probe the postseismic deformation along a daily timescale. Inverting the GPS data from 54 stations to model daily slip on the plate interface reveals how the afterslip distribution jumps around the interface in a somewhat chaotic fashion. Inversion results are validated by aftershock locations, which tend to line up in between patches of high slip on the interface. For certain patches in the slip model we see considerable variability in the slip direction and pulses of acceleration on the afterslip; the cumulative afterslip of the first 430 days released in one seismic event would have a Mw of 8.4. So far, we have solely inverted for afterslip along the plate interface in modelling the postseismic process. Our ongoing research involves investigating the contribution of other processes such as crustal fault slip, viscoelasticity and poroelasticity to the surface deformation field.

Bedford, J.; Moreno, M.; Keiding, M.; Heidbach, O.; Oncken, O.; Lange, D.; Baez, J. C.; Maule GPS Team

2012-04-01

78

Multi-GPU Jacobian Accelerated Computing for Soft Field Tomography  

PubMed Central

Image reconstruction in soft-field tomography is based on an inverse problem formulation, where a forward model is fitted to the data. In medical applications, where the anatomy presents complex shapes, it is common to use Finite Element Models to represent the volume of interest and to solve a partial differential equation that models the physics of the system. Over the last decade, there has been a shifting interest from 2D modeling to 3D modeling, as the underlying physics of most problems are three-dimensional. Though the increased computational power of modern computers allows working with much larger FEM models, the computational time required to reconstruct 3D images on a fine 3D FEM model can be significant, on the order of hours. For example, in Electrical Impedance Tomography applications using a dense 3D FEM mesh with half a million elements, a single reconstruction iteration takes approximately 15 to 20 minutes with optimized routines running on a modern multi-core PC. It is desirable to accelerate image reconstruction to enable researchers to more easily and rapidly explore data and reconstruction parameters. Further, providing high-speed reconstructions are essential for some promising clinical application of EIT. For 3D problems 70% of the computing time is spent building the Jacobian matrix, and 25% of the time in forward solving. In the present work, we focus on accelerating the Jacobian computation by using single and multiple GPUs. First, we discuss an optimized implementation on a modern multi-core PC architecture and show how computing time is bounded by the CPU-to-memory bandwidth; this factor limits the rate at which data can be fetched by the CPU. Gains associated with use of multiple CPU cores are minimal, since data operands cannot be fetched fast enough to saturate the processing power of even a single CPU core. GPUs have a much faster memory bandwidths compared to CPUs and better parallelism. We are able to obtain acceleration factors of 20 times on a single NVIDIA S1070 GPU, and of 50 times on 4 GPUs, bringing the Jacobian computing time for a fine 3D mesh from 12 minutes to 14 seconds. We regard this as an important step towards gaining interactive reconstruction times in 3D imaging, particularly when coupled in the future with acceleration of the forward problem. While we demonstrate results for Electrical Impedance Tomography, these results apply to any soft-field imaging modality where the Jacobian matrix is computed with the Adjoint Method.

Borsic, A.; Attardo, E. A.; Halter, R. J.

2012-01-01

79

Inversions  

ERIC Educational Resources Information Center

|Inversions are fascinating phenomena. They are reversals of the normal or expected order. They occur across a wide variety of contexts. What do inversions have to do with learning spaces? The author suggests that they are a useful metaphor for the process that is unfolding in higher education with respect to education. On the basis of…

Brown, Malcolm

2009-01-01

80

Inversions  

NSDL National Science Digital Library

In this lesson students are introduced to various types of symmetry. After exploring the symmetries that exist with letters of the alphabet, they make inversions of their own name. Suggestions for implementation and support materials are provided.

2011-01-01

81

Timing and Kinematics of Cretaceous to Paleogene inversion at the SE margin of the Central European Basin System: Part 1, Kinematics  

NASA Astrophysics Data System (ADS)

Late Cretaceous to Early Tertiary inversion of the Central European Basin system (CEBS) is remarkably heterogeneous in the mode and timing of structural inversion (i.e., including reactivation of normal faults). Paleogene inversion present in rifts from the British Isles to the Netherlands decreases eastward into the Lower Saxony basin. Further east, in the North East German basin (NEGB), the influence of Paleocene to Eocene events is difficult to prove. There, much or all of the inversion occurred in Late Cretaceous time. E.g., the Dekorp Basin 9601 regional seismic section shows flat lying Paleocene on top of steeply dipping, folded and thrust-faulted Triassic to Upper Cretaceous strata. Thickness variations of Lower Tertiary strata in the southern NEGB mostly result from differential subsidence by salt withdrawal: salt-cored anticlines subsided after Late Cretaceous inversion and formed up to 1400 m deep basins predominantly filled with Eocene to Oligocene sediments. Fission track dating on bedrock from the basement highs in central Germany supports the hypothesis of a short but intense phase of inversion in Late Cretaceous time, although some Early Tertiary exhumation is documented as well. Apart from the timing of inversion, the different parts of the CEBS differ in the magnitudes of uplift and horizontal shortening and in structural style. In the western and central parts of the basin system, Late Cretaceous shortening is focussed on the NW-SE trending Jurassic to Lower Cretaceous extensional basins. In contrast, little shortening is accommodated within the NEGB. Rather, it is concentrated in the Thüringer Wald, Harz and Flechtingen basement uplifts and associated footwall structures on the southern basin margin. There is no clear evidence for increased original thicknesses of the sedimentary cover overlying the basement uplifts. On the contrary, part of the area affected by basement thrusting was underlain by the Eichsfeld-Altmark swell, a long-lived paleogeographic and structural high of Permian-Jurassic age. There is also no evidence for the regional reverse faults being reactivated normal faults, so the basement thrusting does not represent inversion in a strict sense. Still further east in Poland, the magnitude of "true" basin inversion increases again in the Polish basin. Nevertheless, first results of structural balancing across the CEBS suggest that shortening and uplift attained a maximum on a transect crossing the East German basement uplifts. Bulk horizontal NE-SW shortening from Scandinavia to southern Germany is about 15-20 km there. The total shortening decreases westward to a few km on a southern North Sea transect and probably also toward the east, although regional uplift of the Bohemian Massif inducing widespread non-deposition or erosion of Mesozoic strata make this difficult to prove. The irregular arrangement of extensional basins and intervening highs or swells apparently had a stronger effect on shortening styles than magnitudes. A counterintuitive conclusion from the symmetric regional shortening pattern is that the basins were not mechanically weaker than some specific regions of unextended crust. Rather than particularly strong basins this probably indicates weak basin margins, potentially resulting from a thermal anomaly or a previously thickened felsic crust.

Jähne, F.; Kley, J.; Hoffmann, V. E.; Eynatten, H. V.; Dunkl, I.

2009-04-01

82

Kinematic Modeling of a High Mobility Mars Rover  

Microsoft Academic Search

The paper describes a method for kinematic modeling of the Rocky 7 Mars rover. The model is derived for full six degree of freedom motions enabling movements in x,y,z directions, as well as pitch, roll and yaw rotations. Forward kinematic equations are derived using wheel Jacobian matrices. The individual matrices are then combined to form the composite equation for the

Mahmoud Tarokh; Gregory J. Mcdermott; S. Hayati; J. Hung

1999-01-01

83

Singularity analysis of closed-loop kinematic chains  

Microsoft Academic Search

The different kinds of singularities encountered in closed-loop kinematics chains are analyzed. A general classification of these singularities in three main groups, which is based on the properties of the Jacobian matrices of the chain, is described. The identification of the singular configurations is particularly relevant for hard automation modules or robotic devices based on closed kinematic chains, such as

C. Gosselin; J. Angeles

1990-01-01

84

The jacobian conjecture: linear triangularizatlon for cubics in dimension three  

Microsoft Academic Search

It is proved that a polynomial endomorphism of three space which is cubic homogeneous and whose jacobian determinant is a non-zero constant is linearly triangularizable, thereby furnishing a proof of the Jacobian Conjecture for this case. An example is given of a such cubic homogeneous map in dimension four for which linear triangularization fails. Explicit polynomial conditions on the coefficients

David Wright

1993-01-01

85

Study of the {sup 124}Sn(d,p) reaction in inverse kinematics close to the Coulomb barrier  

SciTech Connect

The {sup 2}H({sup 124}Sn,p) reaction has been measured at 562 MeV (4.5 A MeV). Differential cross sections were measured from {theta}{sub c.m}=7 deg. -61 deg. Angular momentum transfers and spectroscopic factors determined using finite range DWBA calculations are in good agreement with earlier measurements performed in normal kinematics.

Jones, K.L.; Cizewski, J.A.; Thomas, J.S. [Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08854-8019 (United States); Kozub, R.L.; Nesaraja, C.D. [Physics Department, Tennessee Technological University, Cookeville, Tennessee 38505 (United States); Baktash, C.; Bardayan, D.W.; Blackmon, J.C.; Shapira, D.; Smith, M.S. [Physics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States); Catford, W.N. [Physics Department, University of Surrey, Guildford, Surrey, GU2 7XH (United Kingdom); Fitzgerald, R.P.; Visser, D.W. [Department of Physics and Astronomy, University of North Carolina, Chapel Hill, North Carolina 27599 (United States); Johnson, M.S. [Oak Ridge Associated Universities, Oak Ridge, Tennessee 37831 (United States); Livesay, R.J. [Colorado School of Mines, Golden, Colorado 80401 (United States); Ma, Z. [Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996 (United States)

2004-12-01

86

The application of striation analysis and focal mechanism stress inversion in deducing the kinematic history of faults: Examples from the Bristol Channel UK and the Ionian Zone Greece  

NASA Astrophysics Data System (ADS)

The present work compliments the application of a methodology, in reviewing and investigating further the kinematic history of faults, based on striation analysis and stress inversion of earthquake focal mechanisms and combines them to refine tectonic modelling and hence improve further hazard assessment. Two areas are chosen for this application: the Bristol Channel, UK and the Ionian Zone, Greece. Striation analysis is carried out in two complementary fault terranes. The first along the northern margin of the Inner Bristol Channel, UK, offers a natural laboratory to study in detail the reactivation history of the inverted Bristol Channel basin; and, the second along the north western coastline of the Ionian Zone, Greece, presents an opportunity to illustrate the relationship between movement of a framework of faults within the external orogenic zone of the Hellenides and the stress deduced from focal mechanisms of earthquakes in the region. The UK example reveals phases of Mesozoic negative inversion of Late Palaeozoic basement frontal and oblique ramp thrust faults, followed by Caenozoic positive inversions of Mesozoic normal and strike slip faults. The Greek example shows an equally composite history of faulting; Tethyan basement strata contain normal faults that pass up sequence and across unconformities into Mesozoic and Caenozoic strata, with thrusts and positively inverted faults recording typical dextral transpression. The fault framework in older strata and the veneers of Recent strata above them display Neotectonic fault histories of sinistral transtension, in addition to the transpression. Since the Ionian Zone lies suitably in the external zone, deformation favours the reactivation of fault lineaments, rather than the genesis of pristine faults. Both examples are used to demonstrate this structural principle. Focal mechanisms of Greek earthquake data are used in stress inversion and the results are applied upon the inherited fault framework and are postulated to reactivate it. For example, structures are selected in the field from the tectonised strata of northern Corfu and from recent geological maps of north western Greece. These data are used in conjunction with the results of stress inversion of focal mechanisms, in order to anticipate and then test the gross senses of fault reactivation. Tests are investigated using structural field techniques and available international striation analysis software modules. The defined framework analysis is applied to both the data from ancient faults, in UK and the focal mechanisms of earthquakes, in Greece. Stress tensors are calculated and fault kinematic histories are evaluated. Hence, this application permits the effects of a modern stress regime to be deduced for a known fault framework, in order to complete and understand fully the kinematic history to the present day. As a corollary, the significant field techniques of tracing major fault lines across regional unconformities and measuring the sense of displacements across these stratigraphic boundaries permit kinematic histories to be defined more precisely in both terranes, than by using only structural techniques.

Melis, Nikolaos S.; Miliorizos, Marios N.; Oshoano Aipoh, Hilary

2013-04-01

87

Evolution of the one-phonon mixed-symmetry 2{sub 1,ms}{sup +} state in even-even Xe isotopes from inverse-kinematics Coulomb excitation  

SciTech Connect

Coulomb excitation experiments in inverse kinematics on beams of stable {sup 134,132,130,128,126,124}Xe ions impinging on a carbon target at energies of 82% of the respective Coulomb barriers have been performed. The one-phonon 2{sub 1,ms}{sup +} states have been tracked and identified in {sup 134,132,130,128}Xe from the 2{sub i,ms}{sup +}{yields}2{sub 1}{sup +} M1 strength distributions and from 0{sub 1}{sup +}{yields}2{sub i,ms}{sup +} E2 strength distributions responsible for the one-step Coulomb excitation processes. The evolution of the one-phonon 2{sub 1,ms}{sup +} state within the seven even-even stable Xe isotopes is here presented.

Coquard, L.; Pietralla, N.; Leske, J.; Moeller, O.; Moeller, T. [Institut fuer Kernphysik, Technische Universitaet Darmstadt, 64289 Darmstadt (Germany); Ahn, T. [Institut fuer Kernphysik, Technische Universitaet Darmstadt, 64289 Darmstadt (Germany); A. W. Wright Nuclear Structure Laboratory, Yale University, New Haven, Connecticut 06520 (United States); Rainovski, G. [Faculty of Physics, St. Kliment Ohridski University of Sofia, 1164 Sofia (Bulgaria); Carpenter, M.; Janssens, R. V. F.; Lister, C. J.; Zhu, S. [Argonne National Laboratory, Argonne, IL 60439 (United States); Bettermann, L.; Rother, W. [Institut fuer Kernphysik, Universitaet Koeln, Zuelpicherstr. 77, 50937 Koeln (Germany)

2009-01-28

88

Lifetime measurement of candidate chiral doublet bands in the {sup 103,104}Rh isotopes with the recoil-distance Doppler-shift method in inverse kinematics  

SciTech Connect

Lifetimes of chiral candidate structures in {sup 103,104}Rh were measured using the recoil distance Doppler-shift method. The Gammasphere detector array was used in conjunction with the Cologne plunger device. Excited states of {sup 103,104}Rh were populated by the {sup 11}B({sup 96}Zr,4n){sup 103}Rh and {sup 11}B({sup 96}Zr,3n){sup 104}Rh fusion-evaporation reactions in inverse kinematics. Three and five lifetimes of levels belonging to the proposed chiral doublet bands are measured in {sup 103}Rh and {sup 104}Rh, respectively. The previously observed even-odd spin dependence of the B(M1)/B(E2) values is caused by the variation in the B(E2) values, whereas the B(M1) values decrease as a function of spin.

Suzuki, T. [Cyclotron and Radio-isotope Center, Tohoku University, Sendai 980-8578 (Japan); Department of Physics, Tohoku University, Sendai 980-8577 (Japan); Rainovski, G. [St. Kliment Ohridski University of Sofia, Sofia 1164 (Bulgaria); Department of Physics and Astronomy, SUNY, Stony Brook, New York 11794-3800 (United States); Koike, T. [Department of Physics, Tohoku University, Sendai 980-8577 (Japan); Ahn, T.; Costin, A. [Department of Physics and Astronomy, SUNY, Stony Brook, New York 11794-3800 (United States); Carpenter, M. P.; Janssens, R. V. F.; Lister, C. J.; Zhu, S. [Physics Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Danchev, M. [Department of Physics, University of Tennessee Knoxville, Tennessee 37996 (United States); Dewald, A. [Institute fuer Kernphysik der Universitaet zu Koeln, D-50937 Koeln (Germany); Joshi, P.; Wadsworth, R. [Department of Physics, University of York, Heslington YO10 5DD (United Kingdom); Moeller, O. [Institute fuer Kernphysik der Universitaet zu Koeln, D-50937 Koeln (Germany); Institut fuer Kernphysik, TU Darmstadt, D-64689, Darmstadt (Germany); Pietralla, N. [Department of Physics and Astronomy, SUNY, Stony Brook, New York 11794-3800 (United States); Institut fuer Kernphysik, TU Darmstadt, D-64689, Darmstadt (Germany); Shinozuka, T. [Cyclotron and Radio-isotope Center, Tohoku University, Sendai 980-8578 (Japan); Timar, J. [Institute of Nuclear Research (ATOMKI), Pf. 51, 4001 Debrecen (Hungary); Vaman, C. [National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824 (United States)

2008-09-15

89

Inverse kinematics of redundant systems driver IKORv1.0-2.0 (full space parameterization with orientation control, platform mobility, and portability)  

SciTech Connect

Few optimization methods exist for path planning of kinematically redundant manipulators. Among these, a universal method is lacking that takes advantage of a manipulator`s redundancy while satisfying possibly varying constraints and task requirements. Full Space Parameterization (FSP) is a new method that generates the entire solution space of underspecified systems of algebraic equations and then calculates the unique solution satisfying specific constraints and optimization criteria. The FSP method has been previously tested on several configurations of the redundant manipulator HERMIES-III. This report deals with the extension of the FSP driver, Inverse Kinematics On Redundant systems (IKOR), to include three-dimensional manipulation systems, possibly incorporating a mobile platform, with and without orientation control. The driver was also extended by integrating two optimized versions of the FSP solution generator as well as the ability to easily port to any manipulator. IKOR was first altered to include the ability to handle orientation control and to integrate an optimized solution generator. The resulting system was tested on a 4 degrees-of-redundancy manipulator arm and was found to successfully perform trajectories with least norm criteria while avoiding obstacles and joint limits. Next, the system was adapted and tested on a manipulator arm placed on a mobile platform yielding 7 degrees of redundancy. After successful testing on least norm trajectories while avoiding obstacles and joint limits, IKORv1.0 was developed. The system was successfully verified using comparisons with a current industry standard, the Moore Penrose Pseudo-Inverse. Finally, IKORv2.0 was created, which includes both the one shot and two step methods, manipulator portability, integration of a second optimized solution generator, and finally a more robust and usable code design.

Hacker, C.J.; Fries, G.A.; Pin, F.G.

1997-01-01

90

Crystal plasticity with Jacobian-Free Newton-Krylov  

NASA Astrophysics Data System (ADS)

The objective of this work is to study potential benefits of solving crystal plasticity finite element method (CPFEM) implicit simulations using the Jacobian-Free Newton-Krylov (JFNK) technique. Implicit implementations of CPFEM are usually solved using Newton's method. However, the inherent non-linearity in the flow rule model that characterizes the crystal slip system deformation on occasions would require considerable effort to form the exact analytical Jacobian needed by Newton's method. In this paper we present an alternative using JFNK. As it does not require an exact Jacobian, JFNK can potentially decrease development time. JFNK approximates the effect of the Jacobian through finite differences of the residual vector, allowing modified formulations to be studied with relative ease. We show that the JFNK solution is identical to that obtained using Newton's method and produces quadratic convergence. We also find that preconditioning the JFNK solution with the elastic tensor provides the best computational efficiency.

Chockalingam, K.; Tonks, M. R.; Hales, J. D.; Gaston, D. R.; Millett, P. C.; Zhang, Liangzhe

2013-05-01

91

Kinematic source parameters determined by time-dependent moment-tensor inversion and an analysis of teleseismic first motions  

Microsoft Academic Search

A waveform-inversion technique was applied to the digitally recorded long-period P-waveform data from the Global Digital Seismograph Network for the May 2 earthquake. The solution was constrained to be purely deviatoric but not to be a double couple. The source depth was determined by finding a trial depth that minimized the misfit to the data. By allowing the elements of

S. A. Sipkin; R. E. Needham

1990-01-01

92

Coordinates, Conversions, and Kinematics  

Microsoft Academic Search

This is a guide to coordinate systems, representations, and geometric relationships between them, for components of the Rochester Robotics Laboratory. The main entities at issue are the joint angles, location variables, and coordinate systems of the Puma, the camera angles and coordinate systems associated with the head, the spatial location of three-dimensional points, and the kinematic and inverse kinematic relationships

Christopher M. Brown; Raymond D. Rimey

93

Kinematic source parameters determined by time-dependent moment-tensor inversion and an analysis of teleseismic first motions  

SciTech Connect

A waveform-inversion technique was applied to the digitally recorded long-period P-waveform data from the Global Digital Seismograph Network for the May 2 earthquake. The solution was constrained to be purely deviatoric but not to be a double couple. The source depth was determined by finding a trial depth that minimized the misfit to the data. By allowing the elements of the moment tensor to be independent, arbitrary functions of time, a gross estimate of the source-time history of the rupture process was obtained. A moderately well constrained fault-plane solution was also obtained by fitting the available long-and short-period teleseismic first-motion data. The strike, dip, and rake of the first-motion solution are 307{degree}, 70{degree}, and 90{degree}, respectively. This solution is very close to the best double-couple of the step-function moment-tensor solution of 303{degree}, 72{degree}, and 97{degree}. The best fitting depth is 11 km and the scalar moment is 4.7 {times} 10{sup 25} dyne-cm. The non-double-couple part of the moment tensor is 28%. This substantial non-double-couple component is apparently due to source complexity in which the strike of the fault plane rotated clockwise during rupture, from a strike of approximately 292{degree} to a strike of 302{degree}.

Sipkin, S.A.; Needham, R.E.

1990-01-01

94

Nuclear-matter density distribution in the neutron-rich nuclei 12,14Be from proton elastic scattering in inverse kinematics  

NASA Astrophysics Data System (ADS)

In the present work, the differential cross sections for small-angle proton elastic scattering on the 12,14Be nuclei were measured in inverse kinematics, using secondary radioactive beams with energies near 700 MeV/u produced with the fragment separator FRS at GSI. The main part of the experimental setup was the active target IKAR, which was used simultaneously as a target and a detector for the recoil protons. Auxiliary detectors for projectile tracking and isotope identification completed the setup. The measured differential cross sections were analyzed using the Glauber multiple-scattering theory. For the evaluation of the data several phenomenological nuclear-matter density parametrizations and a sum of Gaussian parametrization were used. The nuclear-matter radii and radial density distributions of the isotopes 12,14Be were deduced. Extended nuclear-matter density distributions were observed in both isotopes, and the halo structure of 14Be was confirmed. The results were also compared with microscopic few-body and fermionic molecular dynamics model calculations concerning the structure of these neutron-rich nuclei.

Ilieva, S.; Aksouh, F.; Alkhazov, G. D.; Chulkov, L.; Dobrovolsky, A. V.; Egelhof, P.; Geissel, H.; Gorska, M.; Inglessi, A.; Kanungo, R.; Khanzadeev, A. V.; Kiselev, O. A.; Korolev, G. A.; Le, X. C.; Litvinov, Yu. A.; Nociforo, C.; Seliverstov, D. M.; Sergeev, L. O.; Simon, H.; Volkov, V. A.; Vorobyov, A. A.; Weick, H.; Yatsoura, V. I.; Zhdanov, A. A.

2012-02-01

95

A new experimental approach to investigate intermediate-energy proton elastic scattering and breakup reactions on exotic nuclei in inverse kinematics  

NASA Astrophysics Data System (ADS)

We report on a new experimental setup for the investigation of proton induced reactions on exotic nuclei in inverse kinematics. It was installed and successfully used in the scattering study of intermediate-energy protons (˜700MeV/u) on neutron-rich nuclei 6,8He produced with the FRagment Separator (FRS) at the GSI facility, Darmstadt. A new pure liquid-hydrogen target was successfully adapted allowing to obtain low-background data as compared to commonly used (CH2)n targets.Absolute differential cross-sections for elastic (p,6,8He) scattering were obtained at angles corresponding to 0.05?|t|?0.125 (GeV/c)2 of the four-momentum transfer squared (-t) leading to the first diffraction minimum and spanning more than two orders of magnitude. They complement an earlier measurement at smaller angles 0.0025?|t|?0.05 (GeV/c)2 performed at the same energy with an active target. Both data sets agree well in the overlap region t?0.05 (GeV/c)2 and enable a refined and comparative study of the radial distribution of the nuclear matter density.

Kiselev, O. A.; Aksouh, F.; Bleile, A.; Bochkarev, O. V.; Chulkov, L. V.; Cortina-Gil, D.; Dobrovolsky, A. V.; Egelhof, P.; Geissel, H.; Hellström, M.; Isaev, N. B.; Komkov, B. G.; Matoš, M.; Moroz, F. V.; Münzenberg, G.; Mutterer, M.; Mylnikov, V. A.; Neumaier, S. R.; Pribora, V. N.; Seliverstov, D. M.; Sergueev, L. O.; Shrivastava, A.; Sümmerer, K.; Weick, H.; Winkler, M.; Yatsoura, V. I.

2011-06-01

96

Kinematic Error Correction for Minimally Invasive Surgical Robots  

Microsoft Academic Search

Robots are useful tools in minimally invasive surgery, providing benefits such as reduction in hand tremor, navigation, and workspace scaling. Unfortunately, minimally invasive configurations result in two likely sources of kinematic error: port displacement and instrument shaft flexion. For a quasi- static system, a measure is presented that relates the errors in the robot Jacobian to the angular difference between

Ryan A. Beasley; Robert D. Howe; Pierre E. Dupont

2004-01-01

97

Kinematic control of redundant robot manipulators: A tutorial  

Microsoft Academic Search

In this paper, we present a tentatively comprehensive tutorial report of the most recent literature on kinematic control of redundant robot manipulators. Our goal is to lend some perspective to the most widely adopted on-line instantaneous control solutions, namely those based on the simple manipulator's Jacobian, those based on the local optimization of objective functions in the null space of

Bruno Siciliano

1990-01-01

98

Multi-GPU Jacobian accelerated computing for soft-field tomography.  

PubMed

Image reconstruction in soft-field tomography is based on an inverse problem formulation, where a forward model is fitted to the data. In medical applications, where the anatomy presents complex shapes, it is common to use finite element models (FEMs) to represent the volume of interest and solve a partial differential equation that models the physics of the system. Over the last decade, there has been a shifting interest from 2D modeling to 3D modeling, as the underlying physics of most problems are 3D. Although the increased computational power of modern computers allows working with much larger FEM models, the computational time required to reconstruct 3D images on a fine 3D FEM model can be significant, on the order of hours. For example, in electrical impedance tomography (EIT) applications using a dense 3D FEM mesh with half a million elements, a single reconstruction iteration takes approximately 15-20 min with optimized routines running on a modern multi-core PC. It is desirable to accelerate image reconstruction to enable researchers to more easily and rapidly explore data and reconstruction parameters. Furthermore, providing high-speed reconstructions is essential for some promising clinical application of EIT. For 3D problems, 70% of the computing time is spent building the Jacobian matrix, and 25% of the time in forward solving. In this work, we focus on accelerating the Jacobian computation by using single and multiple GPUs. First, we discuss an optimized implementation on a modern multi-core PC architecture and show how computing time is bounded by the CPU-to-memory bandwidth; this factor limits the rate at which data can be fetched by the CPU. Gains associated with the use of multiple CPU cores are minimal, since data operands cannot be fetched fast enough to saturate the processing power of even a single CPU core. GPUs have much faster memory bandwidths compared to CPUs and better parallelism. We are able to obtain acceleration factors of 20 times on a single NVIDIA S1070 GPU, and of 50 times on four GPUs, bringing the Jacobian computing time for a fine 3D mesh from 12 min to 14 s. We regard this as an important step toward gaining interactive reconstruction times in 3D imaging, particularly when coupled in the future with acceleration of the forward problem. While we demonstrate results for EIT, these results apply to any soft-field imaging modality where the Jacobian matrix is computed with the adjoint method. PMID:23010857

Borsic, A; Attardo, E A; Halter, R J

2012-09-26

99

Kinematic Analysis of the Arid Manipulator.  

National Technical Information Service (NTIS)

The kinematic structure of the ARID manipulator lends itself to simple forward and inverse kinematics analysis. The purpose of this paper is to fully document and verify an existing analysis. The symbolic software package MATHEMATICA was used to produce a...

K. L Doty

1992-01-01

100

Power system steady-state stability and the load-flow Jacobian  

Microsoft Academic Search

The relationship is presented between a detailed power system dynamic model and a standard load-flow model. The linearized dynamic model is examined to show how the load-flow Jacobian appears in the system dynamic-state Jacobian for evaluating steady-state stability. Two special cases are given for the situation when singularity of the load-flow Jacobian implies singularity of the system dynamic-state Jacobian. The

P. W. Sauer; M. A. Pai

1990-01-01

101

Efficient parallel algorithms and VLSI architectures for manipulator Jacobian computation  

SciTech Connect

The real-time computation of manipulator Jacobian that relates the manipulator joint velocities to the linear and angular velocities of the manipulator end-effector is pursued. Since the Jacobian can be expressed in the form of the first-order linear recurrence, the time lower bound to complete the Jacobian can be proved to be of order O(N) on uniprocessor computers, and of order O(log{sub 2}N) on both parallel single-instruction-stream multiple-data-stream (SIMD) computers and parallel VLSI pipelines, where N is the number of links of the manipulator. To achieve the computation time lower bound, we developed the generalized-k method on uniprocessor computers, the parallel forward and backward recursive doubling algorithm (PFABRD) on SIMD computers, and a parallel systolic architecture on VLSI pipelines. All the methods are capable of computing the Jacobian at any desired reference coordinate frame k from the base coordinate frame to the end-effector coordinate frame. The computation effort in terms of floating point operations is minimal when k is in the range (4, N {minus} 3) for the generalized-k method, and k = (N + 1)/2 for both the PFABRD algorithm and the parallel pipeline.

Yeung, T.B. (LSI Logic Corp., Milpitas, CA (US)); Lee, C.S.G. (Of Electrical Enginerring, Purdue Univ., West Lafayette, IN (US))

1989-09-01

102

Jacobian matrix-based observability analysis for state estimation  

Microsoft Academic Search

In this paper, numerical observability analysis is restudied. Algorithms to determine observable islands and to decide a minimal set of pseudo-measurements to make the unobservable system observable are presented. The algorithms make direct use of the measurement Jacobian matrix. Gaussian elimination, which makes the whole process of observability analysis simple and effective, is the only computation required by the algorithms.

B. Gou

2006-01-01

103

The bounded Jacobian approach to nonlinear observer design  

Microsoft Academic Search

This paper presents a new observer design technique for a nonlinear system with a globally (or locally) bounded Jacobian. The approach utilized is to use the mean value theorem to express the nonlinear error dynamics as a convex combination of known matrices with time varying coefficients. The observer gains are then obtained by solving linear matrix inequalities (LMIs). The developed

G. Phanomchoeng; R. Rajamani

2010-01-01

104

On the equivariant algebraic Jacobian for curves of genus two  

NASA Astrophysics Data System (ADS)

We present a treatment of the algebraic description of the Jacobian of a generic genus two plane curve which exploits an SL2(k) equivariance and clarifies the structure of Flynn’s 72 defining quadratic relations. The treatment is also applied to the Kummer variety.

Athorne, Chris

2012-04-01

105

Direct kinematic solution of a Stewart platform  

Microsoft Academic Search

The Stewart platform is a fully parallel, six-degree-of-freedom manipulator mechanism. Although its inverse kinematics have been extensively studied, no solutions to the direct position kinematics problem have been previously presented in the literature. A solution of the direct kinematics problem of the case in which the six limbs form three concurrent pairs at either the base or the hand member

PRABJOT NANUA; KENNETH J. WALDRON; VASUDEVA MURTHY

1990-01-01

106

Optimum Kinematic Design for a Seven Degree of Freedom Manipulator  

Microsoft Academic Search

oll axes of the forearm andhand, reducing by one the degrees of freedom.Singularities are manifested in inverse kinematicproblems where it is desired to find joint velocitiesthat correspond to desired hand velocities. Joint velocities` and hand velocities x are related by theJacobian matrix J: x = J `where the 6-dimensional hand velocity x = ( p !)consists of a linear velocity

John M. Hollerbach

1985-01-01

107

Adaptive Tracking Control for Robots with Unknown Kinematic and Dynamic Properties  

Microsoft Academic Search

It has been almost two decades since the first globally tracking con- vergent adaptive controllers were derived for robot with dynamic uncertainties. However, the problem of concurrent adaptation to both kinematic and dynamic uncertainties has never been system- atically solved. This is the subject of this paper. We derive a new adaptive Jacobian controller for trajectory tracking of robot with

Chien-chern Cheah; Chao Liu; Jean-jacques E. Slotine

2006-01-01

108

Direct kinematics of a double parallel robot arm for real time velocity control  

Microsoft Academic Search

The determination of the direct kinematics of a parallel mechanism is a difficult problem but must be solved for practical\\u000a application. This paper presents the efficient formulation of the direct kinematics and the Jacobian of a double parallel\\u000a robot arm for velocity control. The robot arm consists of two parallel mechanisms, and a central axis that generates positional\\u000a and orientational

Min Ki Lee; Kun Woo Park

1998-01-01

109

REACTIVE TRANSPORT MODELING USING A PARALLEL FULLY-COUPLED SIMULATOR BASED ON PRECONDITIONED JACOBIAN-FREE NEWTON-KRYLOV  

SciTech Connect

Systems of multicomponent reactive transport in porous media that are large, highly nonlinear, and tightly coupled due to complex nonlinear reactions and strong solution-media interactions are often described by a system of coupled nonlinear partial differential algebraic equations (PDAEs). A preconditioned Jacobian-Free Newton-Krylov (JFNK) solution approach is applied to solve the PDAEs in a fully coupled, fully implicit manner. The advantage of the JFNK method is that it avoids explicitly computing and storing the Jacobian matrix during Newton nonlinear iterations for computational efficiency considerations. This solution approach is also enhanced by physics-based blocking preconditioning and multigrid algorithm for efficient inversion of preconditioners. Based on the solution approach, we have developed a reactive transport simulator named RAT. Numerical results are presented to demonstrate the efficiency and massive scalability of the simulator for reactive transport problems involving strong solution-mineral interactions and fast kinetics. It has been applied to study the highly nonlinearly coupled reactive transport system of a promising in situ environmental remediation that involves urea hydrolysis and calcium carbonate precipitation.

Luanjing Guo; Chuan Lu; Hai Huang; Derek R. Gaston

2012-06-01

110

Real-time estimate of body kinematics during a planar squat task using a single inertial measurement unit.  

PubMed

This study aimed at the real-time estimation of the lower-limb joint and torso kinematics during a squat exercise, performed in the sagittal plane, using a single inertial measurement unit placed on the lower back. The human body was modeled with a 3-DOF planar chain. The planar IMU orientation and vertical displacement were estimated using one angular velocity and two acceleration components and a weighted Fourier linear combiner. The ankle, knee, and hip joint angles were thereafter obtained through a novel inverse kinematic module based on the use of a Jacobian pseudoinverse matrix and null-space decoupling. The aforementioned algorithms were validated on a humanoid robot for which the mechanical model used and the measured joint angles virtually exhibited no inaccuracies. Joint angles were estimated with a maximal error of 1.5°. The performance of the proposed analytical and experimental methodology was also assessed by conducting an experiment on human volunteers and by comparing the relevant results with those obtained through the more conventional photogrammetric approach. The joint angles provided by the two methods displayed differences equal to 3±1°. These results, associated with the real-time capability of the method, open the door to future field applications in both rehabilitation and sport. PMID:23392337

Bonnet, Vincent; Mazzà, Claudia; Fraisse, Philippe; Cappozzo, Aurelio

2013-02-05

111

An application of Newton–Puiseux charts to the Jacobian problem  

Microsoft Academic Search

We study 2-dimensional Jacobian maps using so-called Newton–Puiseux charts. These are multi-valued coordinates near divisors of resolutions of indeterminacies at infinity of the Jacobian map in the source space as well as in the target space. The map expressed in these charts takes a very simple form, which allows us to detect a series of new analytical and topological properties.

Henryk ?o??dek

2008-01-01

112

Study of bound and unbound states in the halo nucleus ^11Be using the ^10Be(d,p) reaction in inverse kinematics  

NASA Astrophysics Data System (ADS)

Light neutron-rich nuclei have been used widely as test cases for ab initio theory, especially to test its ability to predict phenomena that do not occur in stable nuclei, such as halo structure. Extensive experimental data demonstrates that level inversion of the lowest states leads to halo properties in the ground state of ^11Be. Less is known, however, about the excited states of this nucleus. Specifically, the spectroscopic factor of the only bound excited state is disputed and spin-parity assignments for the unbound states are unconfirmed or tentative. A neutron transfer experiment at the HRIBF should improve our understanding of these states. The setup of this experiment will be described, including advancements in fast-timing MCP based detectors for low-Z beams, detection of recoils at small lab angles, and detector arrangement for the ORRUBA array.

Schmitt, K. T.

2009-05-01

113

A dynamic Jacobian estimation method for uncalibrated visual servoing  

Microsoft Academic Search

A dynamic Broyden's method is presented for use in a quasi-Newton control scheme for model-independent vision guided robotic control. Model independent visual servo control is defined as using visual feedback to control a robot without precisely calibrated kinematic and camera models. The control problem is formulated as a nonlinear least squares optimization. For the moving target case, this results in

Jenelle Armstrong Piepmeier; Gary V. McMurray; Harvey Lipkin

1999-01-01

114

Inverse problem in transformation optics  

NASA Astrophysics Data System (ADS)

The straightforward method of transformation optics implies that one starts from the coordinate transformation and determines the Jacobian matrix, the fields and material parameters of the cloak. However, the coordinate transformation appears as an optional function: it is not necessary to know it. We offer the solution of some sort of inverse problem: starting from the fields in the invisibility cloak we directly derive the permittivity and permeability tensors of the cloaking shell. This approach can be useful for finding material parameters for the specified electromagnetic fields in the cloaking shell without knowing the coordinate transformation.

Novitsky, A. V.

2011-03-01

115

Timing and Kinematics of Cretaceous to Paleogene inversion at the SE margin of the Central European Basin System: Part 2, Thermochronology  

NASA Astrophysics Data System (ADS)

During the Late Cretaceous to Early Tertiary some parts of the Central European Basin System (CEBS) were uplifted along NW-SE to WNW-ESE striking compressive fault systems. As a result Pre-Zechstein (Permian) basement is exposed at the southern border of the CEBS from Central Germany to the sudetes still further east (e.g. Harz Mountains, Thuringian Forest). Thrust-related basins like the Subhercynian Cretaceous Basin (SCB) in the foreland of the Harz Mountains accumulated up to 2500m of siliciclastic and chemical sediments in only 10 million years (Late Turonian to Lower Campanian, Voigt et al., 2006). By means of low-temperature thermochronology it is possible to characterise these basin inversion processes with respect to timing, pattern and rates of cooling and exhumation. Differed authors have already applied Apatite Fission Track analysis (AFT) in certain areas of the southern margin of CEBS. Thomson and Zeh (2000) published AFT apparent ages of 69 to 81 Ma for the Ruhla Crystalline Complex in the Thuringian Forest. Similar AFT-ages (73-84 Ma) of granitoids from the Harz Mountains were reported by Thomson et al. (1997). The late Carboniferous felsic volcanic rocks near Halle yield a much broader range of AFT apparent ages (75-108 Ma; Jacobs and Breitkreuz, 2003). Comparable AFT-ages (84-90 Ma) had been also observed for gabbros from the north-eastern part of the Mid German Crystalline High (Ventura et al. 2003). The present study tries to bridge some of the major gaps in the regional distribution of thermochronological data by analysing samples from central and southern parts of the CEBS. Overall almost 50 AFT-ages from Saxony-Anhalt, Lower Saxony, Thuringia, Hesse and North Rhine-Westphalia were measured. Emphasis is placed on the regions from the Harz Mountains to the Rhenish Uplands and the Thuringian Forest and its foreland. Furthermore, apatite (U-Th)/He thermochronology is used to better constrain the time-temperature history models. Apart from some mixed age information two different age groups can be recognized. A major group that is similar to the one reported above points to a short but intense pulse of exhumation and inversion in Coniacian to Campanian time. A younger, less significant age cluster yields information on a second phase of cooling and exhumation in the Paleocene-Eocene. The length distribution of AFT data leads to the assumption of rapid, partially multi-phase, exhumation events. In addition, the data of this study provides indications for thick Jurassic burial that likely reflect phases of Mesozoic extensional tectonics in at least parts of the CEBS. Jacobs, J., Breitkreuz, C. (2003): Zircon and apatite fission-track thermochronology of Late Carboniferous volcanic rocks of the NE German Basin. International Journal of Earth Sciences (Geologische Rundschau), 92, 165-172. Thomson, S., Brix, M., Carter, A. (1997): Late Cretaceous denudation of the Harz Massif assessed by apatite fission track analysis. In: G. Büchel and H. Lützner (Editors), Regionale Geologie von Mitteleuropa, 149. Hauptversammlung Deutsche Geologische Gesellschaft, Jena. Schriftenreihe der Deutschen Geologischen Gesellschaft, 3, 115. Thomson, S.N., Zeh, A. (2000): Fission-track thermochronology of the Ruhla Crystalline Complex:. New constraints on the post-Variscan thermal evolution of the NW Saxo-Bohemian Massif. Tectonophysics, 324, 17-35. Ventura, B., Lisker, F., Kopp, J. (2003): Apatite fission track data from the dill-core Züllsdorf 1/63: implications for the reconstruction of the post Variscan exhumation of the Mid German Crystalline High. Zeitschrift für Geologische Wissenschaften, 31, 251-261. Voigt, T., Wiese, F., von Eynatten, H., Franzke, H.-J. & Gaupp, R. (2006): Facies evolution of syntectonic Upper Cretaceous deposits in the Subhercynian Cretaceous Basin and adjoining areas (Germany). Zeitschrift der Deutschen Gesellschaft für Geowissenschaften, 157/2, 203-244.

Hoffmann, V.-E.; Dunkl, I.; von Eynatten, H.; Jähne, F.; Voigt, T.; Kley, J.

2009-04-01

116

Shotput kinematics made simple  

NASA Astrophysics Data System (ADS)

We show that some results in the kinematics of a point particle can be easily recalled by introducing simple definitions. In particular, in the parabolic motion of a particle thrown from a height h above the origin O at an angle ? from the horizontal direction, the optimum angle ?* for reaching the maximum distance Rmax on the ground, measured from the origin, can be found by calculating the inverse tangent of the ratio between the initial velocity V0 and the final velocity Vf. The value of Rmax is itself found to be easily expressed as V0Vf/g, g being the acceleration due to gravity.

Faella, O.; De Luca, R.

2013-11-01

117

Inverse plasma equilibria  

SciTech Connect

We illustrate in some detail a 2D inverse-equilibrium solver that was constructed to analyze tokamak configurations and stellarators (the latter in the context of the average method). To ensure that the method is suitable not only to determine equilibria, but also to provide appropriately represented data for existing stability codes, it is important to be able to control the Jacobian, tilde J is identical to delta(R,Z)/delta(rho, theta). The form chosen is tilde J = J/sub 0/(rho)R/sup l/rho where rho is a flux surface label, and l is an integer. The initial implementation is for a fixed conducting-wall boundary, but the technique can be extended to a free-boundary model.

Hicks, H.R.; Dory, R.A.; Holmes, J.A.

1983-01-01

118

Lorentz Kinematics  

Microsoft Academic Search

In this paper we present the foundation of a new kinematics. It is based on the Lorentz transformations. The standard initial premises (rejecting some postulates of the Special Theory of Relativity (STR)) result in a notion about the existence of the structure of Nature made of one-dimensional threads, which connect all material particles. It is shown that these premises also

Michail M. Kononenko

1998-01-01

119

Kinematics simulation of an aided fruit-harvesting manipulator based on ADAMS  

Microsoft Academic Search

As a main type of agricultural robot, fruit harvesting robot has a great potential in agriculture production. In this context, a formulation of the manipulator based on Danevit-Hartenberg is educed for the kinematics equation, and the virtual model of manipulator is developed. The kinematics is studied and inverse kinematics is obtained based on algebraic method. The kinematics simulation of the

Yujie Cui; Jianning Hua; Pu Shi

2010-01-01

120

A new family Jacobian solver for global three-dimensional modeling of atmospheric chemistry  

Microsoft Academic Search

We present a new technique to solve complex sets of photochemical rate equations that is applicable to global modeling of the troposphere and stratosphere. The approach is based on the concept of ``families'' of species, whose chemical rate equations are tightly coupled. Variations of species concentrations within a family can be determined by inverting a linearized Jacobian matrix representing the

Xuepeng Zhao; Richard P. Turco; Mei Shen

1999-01-01

121

Extracting the left and right critical eigenvectors from the LDU-decomposed non-symmetric Jacobian matrix in stability problems  

NASA Astrophysics Data System (ADS)

In the previous publications of the authors, an eigenanalysis-free computational procedure has been proposed to extract the bifurcation buckling mode(s) from the LDL T -decomposed symmetric stiffness matrix in the vicinity of a stability point. Any eigensolver, for instance, inverse iteration or subspace method, is not necessary. The procedure has been verified in numerical examples and well works in multiple and clustered bifurcation problems too. This present paper will extend the eigenanalysis-free procedure to the LDU-decomposed non-symmetric Jacobian matrix, from which both left and right critical eigenvectors relevant to the stability point may be extracted in a similar way. The idea is mathematical and totally independent of the physical problem to be solved, so that it is applicable to any non-symmetric square matrix in stability problems including plasticity with non-associated flow rules, contact and fluid-structure interaction. The linear-algebraic background of non-symmetric eigenvalue problems is firstly described. The present paper will then mention the role play of the left and right critical eigenvectors in stability analysis and the eigenanalysis-free LDU-procedure is proposed. Numerical examples of elastoplastic bifurcation are illustrated for verification and discussion. In APPENDICES, a bench model visualizes the mechanical meaning of the left and right critical singular vectors of a rectangular matrix.

Fujii, Fumio; Yamakawa, Yuki; Noguchi, Hirohisa

2010-07-01

122

Computational kinematics of multi-arm manipulators  

NASA Astrophysics Data System (ADS)

Kinematics of multi-arm/multi-loop manipulator systems entail highly nonlinear and coupled systems of equations. This thesis studies and offers methods for topology and kinematic analysis of these systems. In particular, computational complexities, which has so far prevented the development of robust and reliable routines for such analysis, are studied and efficient remedies and solutions developed. Following are the steps taken towards development of these solutions: a new description for the topology of the multi-arm manipulator system resulting in an expression containing information about structure of individual arms; formulation of a unique Jacobian sub-matrix containing differential relations between joint rates and end effectors' velocities of the entire system irrespective of the topology; a new definition for performance evaluation of the manipulator system based on displacement of an entire body from one point to another; a new description for equations of motion based on Euler angles and their derivatives resulting in an exact solution for evaluation of deviation of end effectors between current and goal locations; and significant modifications for removing the manipulator system from a near-singular or hard to reach position.

Vahidi, Siamak

1992-07-01

123

ADIFOR working note {number_sign}2: Using ADIFOR to compute dense and sparse Jacobians  

SciTech Connect

ADIFOR is a source translator that, given a collection of Fortran subroutines for the computation of a ``function,`` produces Fortran code for the computation of the derivatives of this function. More specifically, ADIFOR produces code to compute the matrix-matrix product JS, where J is the Jacobian of the ``function`` with respect to the user-defined independent variables, and S is the composition of the derivative objects corresponding to the independent variables. This interface is flexible; by setting S = x, one can compute the matrix-vector product Jx, or by setting S = I, one can compute the whole Jacobian J. Other initializations of S allow one to exploit a known sparsity structure of J. This paper illustrates the proper initialization of ADIFOR-generated derivative codes and the exploitation of a known structure of J.

Bischof, C.; Hovland, P.

1992-01-01

124

ADIFOR working note. number sign. 2: Using ADIFOR to compute dense and sparse Jacobians  

SciTech Connect

ADIFOR is a source translator that, given a collection of Fortran subroutines for the computation of a function,'' produces Fortran code for the computation of the derivatives of this function. More specifically, ADIFOR produces code to compute the matrix-matrix product JS, where J is the Jacobian of the function'' with respect to the user-defined independent variables, and S is the composition of the derivative objects corresponding to the independent variables. This interface is flexible; by setting S = x, one can compute the matrix-vector product Jx, or by setting S = I, one can compute the whole Jacobian J. Other initializations of S allow one to exploit a known sparsity structure of J. This paper illustrates the proper initialization of ADIFOR-generated derivative codes and the exploitation of a known structure of J.

Bischof, C.; Hovland, P.

1992-01-01

125

A direct matrix method for computing analytical Jacobians of discretized nonlinear integro-differential equations  

NASA Astrophysics Data System (ADS)

In this article, we present a simple direct matrix method for analytically computing the Jacobian of nonlinear algebraic equations that arise from the discretization of nonlinear integro-differential equations. The method is based on a formulation of the discretized equations in vector form using only matrix-vector products and component-wise operations. By applying simple matrix-based differentiation rules, the matrix form of the analytical Jacobian can be calculated with little more difficulty than required to compute derivatives in single-variable calculus. After describing the direct matrix method, we present numerical experiments demonstrating the computational performance of the method, discuss its connection to the Newton-Kantorovich method and apply it to illustrative 1D and 2D example problems from electrochemical transport.

Chu, Kevin T.

2009-08-01

126

Efficient Algorithms for the Kinematics and Path Planning of Manipulator  

Microsoft Academic Search

The two basic problems of the automatic control of robotic manipulators are the kinematics and the path planning, which are the fundamental for computer controlled robots. The article presented fast and efficient algorithms for the inverse kinematics and path planning of manipulator consisting of six revolute joints. Through the control, we cause the end-effector of the manipulator to the maximum

Dequan Guo; Hui Ju; Yuqin Yao; Feng Ling; Tianxiang Li

2009-01-01

127

The inverse mapping and distortion measures for 8-node hexahedral isoparametric elements  

NASA Astrophysics Data System (ADS)

The inverse relations of the isoparametric mapping for the 8-node hexahedra are derived by using the theory of geodesics in differential geometry. Such inverse relations assume the form of infinite power series in the element geodesic coordinates, which are shown to be the skew Cartesian coordinates determined by the Jacobian of the mapping evaluated at the origin. By expressing the geodesic coordinates in turn in terms of the isoparametric coordinates, the coefficients in the resulted polynomials are suggested to be the distortion parameters of the element. These distortion parameters can be used to sompletely describe the inverse relations and the determinant of the Jacobian of the mapping. The meanings of them can also be explained geometrically and mathematically. These methods of defining the distortion measures and deriving the inverse relations of the mapping are completely general, and can be applied to any other two-or three-dimensional isoparametric elements.

Yuan, K.-Y.; Huang, Y.-S.; Yang, H.-T.; Pian, T. H. H.

1994-05-01

128

Addition formulae over the Jacobian pre-image of hyperelliptic Wirtinger varieties  

Microsoft Academic Search

Using results on Frobenius-Stickelberger-type relations for hyperelliptic curves (Y. ^ Onishi, Proc. Edinb. Math. Soc. (2), 48 (2005) p.705-742), we provide certain ad- dition formulae for any symmetric power of the curves, which hold on the strata Wk, the pre-images in the Jacobian of the classical Wirtinger varieties. As an appendix, we give similar relations for a trigonal curve y3

J. C. Eilbeck; V. Z. ENOLSKII; S. Matsutani; E. Previato

2008-01-01

129

Computing Gradient Vector and Jacobian Matrix in Arbitrarily Connected Neural Networks  

Microsoft Academic Search

This paper describes a new algorithm with neuron-by-neuron computation methods for the gradient vector and the Jacobian matrix. The algorithm can handle networks with arbitrarily connected neurons. The training speed is comparable with the Levenberg-Marquardt algorithm, which is currently considered by many as the fastest algorithm for neural network training. More importantly, it is shown that the computation of the

Bogdan M. Wilamowski; Nicholas J. Cotton; Okyay Kaynak; GÜnhan Dundar

2008-01-01

130

A COMPARISON OF METHODS FOR IDENTIFYING THE JACOBIAN FOR UNCONTROLLED MANIFOLD VARIANCE ANALYSIS  

PubMed Central

Uncontrolled Manifold (UCM) analysis has been used to identify a component of joint variance leading to pointer-tip position variability and a component representing motor abundant joint combinations corresponding to an equivalent hand position. A Jacobian is required for UCM analysis, typically derived from an analytic model relating joint postures to pointer-tip position. Derivation of the Jacobian is often non-trivial, however, because of the complexity of the system being studied. In this article, we compared the effect of different methods of deriving the Jacobian on results of UCM analyses during reaching. Jacobian matrices were determined at each percentage of the reach across trials using one of the three methods: (M1) partial derivatives of the geometric model relating ten joint postures, segment lengths and pointer length to the position of a hand-mounted pointer tip; or (M2–M3) as the coefficients of linear regression between the ten joint postures and either (M2) the pointer tip position measured directly from motion capture or (M3) the pointer-tip position estimated from the geometric model. For all methods, motor abundant joint variance (VUCM) was larger than joint variance leading to a variable pointer-tip position (VORT). Results did not differ among methods prior to the time of peak velocity. Thereafter, M2 yielded lower VORT and slightly higher VUCM compared to M1. Method M3 was used to disambiguate the possible effect of estimating model parameters for the geometric model on the M1–M2 comparison. The advantages of the use of linear regression method in the UCM approach are discussed.

Ferreira de Freitas, Sandra Maria Sbeghen; Scholz, John Peter

2009-01-01

131

Solvable 2-dimensional rational chaotic map defined by Jacobian elliptic functions  

Microsoft Academic Search

Cryptanalysis needs a great deal of pseudo-random numbers. The Jacobian elliptic Chebyshev rational map and its associated binary function have been introduced for generating a sequence of independent and identically distributed (i.i.d.) binary random variables. We have shown that the derivative of an elliptic function induces an elliptic curve and a 2-dimensional rational map. Such a rational map is shown

Aya Kato; Tohru Kohda

2005-01-01

132

Introducing the Jacobian-volume-histogram of deforming organs: application to parotid shrinkage evaluation  

NASA Astrophysics Data System (ADS)

The Jacobian of the deformation field of elastic registration between images taken during radiotherapy is a measure of inter-fraction local deformation. The histogram of the Jacobian values (Jac) within an organ was introduced (JVH—Jacobian-volume-histogram) and first applied in quantifying parotid shrinkage. MVCTs of 32 patients previously treated with helical tomotherapy for head-neck cancers were collected. Parotid deformation was evaluated through elastic registration between MVCTs taken at the first and last fractions. Jac was calculated for each voxel of all parotids, and integral JVHs were calculated for each parotid; the correlation between the JVH and the planning dose-volume histogram (DVH) was investigated. On average, 82% (±17%) of the voxels shrinks (Jac < 1) and 14% (±17%) shows a local compression >50% (Jac < 0.5). The best correlation between the DVH and the JVH was found between V10 and V15, and Jac < 0.4-0.6 (p < 0.01). The best constraint predicting a higher number of largely compressing voxels (Jac0.5<7.5%, median value) was V15 >= 75% (OR: 7.6, p = 0.002). Jac and the JVH are promising tools for scoring/modelling toxicity and for evaluating organ/contour variations with potential applications in adaptive radiotherapy.

Fiorino, Claudio; Maggiulli, Eleonora; Broggi, Sara; Liberini, Simone; Mauro Cattaneo, Giovanni; Dell'Oca, Italo; Faggiano, Elena; Di Muzio, Nadia; Calandrino, Riccardo; Rizzo, Giovanna

2011-06-01

133

Reference Jacobian Optimization-Based Rezone Strategies for Arbitrary Lagrangian Eulerian Methods  

NASA Astrophysics Data System (ADS)

The philosophy of the arbitrary Lagrangian-Eulerian (ALE) methodology for solving multidimensional fluid flow problems is to move the computational grid, using the flow as a guide, to improve the accuracy and efficiency of the simulation. A principal element of ALE is the rezone phase in which a ``rezoned'' grid is created that is adapted to the fluid motion. We will describe a general rezone strategy that ensures the continuing geometric quality of the computational grid, while keeping the ``rezoned'' grid as close as possible to the Lagrangian grid at each time step. Although the methodology can be applied to more general grid types, here we restrict ourselves to logically rectangular grids in two dimensions. Our rezoning phase consists of two components: a sequence of local optimizations followed by a single global optimization. The local optimization defines a set of ``reference'' Jacobians which incorporates our definition of mesh quality at each point of the grid. The set of reference Jacobians then is used in the global optimization. At each node we form a local patch from the adjacent cells of the Lagrangian grid and construct a local realization of the Winslow smoothness functional on this patch. Minimization of this functional with respect to the position of the central node defines its ``virtual'' location (the node is not actually moved at this stage). By connecting this virtually moved node to its (stationary) neighbors, we define a reference Jacobian that represents the best locally achievable geometric grid quality. The ``rezoned'' grid results from a minimization (where the points are actually moved) of a global objective function that measures the distance (in a least-squares sense) between the Jacobian of the rezoned grid and the reference Jacobian. This objective function includes a ``barrier'' that penalizes grids whose cells are close to being inverted. The global objective function is minimized by direct optimization leading to the rezoned grid. We provide numerical examples to demonstrate the robustness and effectiveness of our methodology on model examples as well as for ALE calculations of Rayleigh-Taylor unstable flow. .

Knupp, Patrick; Margolin, Len G.; Shashkov, Mikhail

2002-02-01

134

Three-dimensional parallel distributed inversion of CSEM data using a direct forward solver  

NASA Astrophysics Data System (ADS)

For 3-D inversion of controlled-source electromagnetic (CSEM) data, increasing availability of high-performance computers enables us to apply inversion techniques that are theoretically favourable, yet have previously been considered to be computationally too demanding. We present a newly developed parallel distributed 3-D inversion algorithm for interpreting CSEM data in the frequency domain. Our scheme is based on a direct forward solver and uses Gauss-Newton minimization with explicit formation of the Jacobian. This combination is advantageous, because Gauss-Newton minimization converges rapidly, limiting the number of expensive forward modelling cycles. Explicit calculation of the Jacobian allows us to (i) precondition the Gauss-Newton system, which further accelerates convergence, (ii) determine suitable regularization parameters by comparing matrix norms of data- and model-dependent terms in the objective function and (iii) thoroughly analyse data sensitivities and interdependencies. We show that explicit Jacobian formation in combination with direct solvers is likely to require less memory than combinations of direct solvers and implicit Jacobian usage for many moderate-scale CSEM surveys. We demonstrate the excellent convergence properties of the new inversion scheme for several synthetic models. We compare model updates determined by solving either a system of normal equations or, alternatively, a linear least-squares system. We assess the behaviour of three different stabilizing functionals in the framework of our inversion scheme, and demonstrate that implicit regularization resulting from incomplete iterative solution of the model update equations helps stabilize the inversion. We show inversions of models with up to two million unknowns in the forward solution, which clearly demonstrates applicability of our approach to real-world problems.

Grayver, A. V.; Streich, R.; Ritter, O.

2013-06-01

135

Compactified Strings as Quantum Statistical Partition Function on the Jacobian Torus  

SciTech Connect

We show that the solitonic contribution of toroidally compactified strings corresponds to the quantum statistical partition function of a free particle living on higher dimensional spaces. In the simplest case of compactification on a circle, the Hamiltonian is the Laplacian on the 2g-dimensional Jacobian torus associated with the genus g Riemann surface corresponding to the string world sheet. T duality leads to a symmetry of the partition function mixing time and temperature. Such a classical-quantum correspondence and T duality shed some light on the well-known interplay between time and temperature in quantum field theory and classical statistical mechanics.

Matone, Marco; Pasti, Paolo; Shadchin, Sergey; Volpato, Roberto [Dipartimento di Fisica 'G. Galilei' and Istituto Nazionale di Fisica Nucleare, Universita di Padova, Via Marzolo, 8-35131 Padova (Italy)

2006-12-31

136

Recovery Discontinuous Galerkin Jacobian-Free Newton-Krylov Method for All-Speed Flows  

SciTech Connect

A novel numerical algorithm (rDG-JFNK) for all-speed fluid flows with heat conduction and viscosity is introduced. The rDG-JFNK combines the Discontinuous Galerkin spatial discretization with the implicit Runge-Kutta time integration under the Jacobian-free Newton-Krylov framework. We solve fully-compressible Navier-Stokes equations without operator-splitting of hyperbolic, diffusion and reaction terms, which enables fully-coupled high-order temporal discretization. The stability constraint is removed due to the L-stable Explicit, Singly Diagonal Implicit Runge-Kutta (ESDIRK) scheme. The governing equations are solved in the conservative form, which allows one to accurately compute shock dynamics, as well as low-speed flows. For spatial discretization, we develop a “recovery” family of DG, exhibiting nearly-spectral accuracy. To precondition the Krylov-based linear solver (GMRES), we developed an “Operator-Split”-(OS) Physics Based Preconditioner (PBP), in which we transform/simplify the fully-coupled system to a sequence of segregated scalar problems, each can be solved efficiently with Multigrid method. Each scalar problem is designed to target/cluster eigenvalues of the Jacobian matrix associated with a specific physics.

HyeongKae Park; Robert Nourgaliev; Vincent Mousseau; Dana Knoll

2008-07-01

137

A dexterity measure for the kinematic control of a multifinger, multifreedom robot hand  

SciTech Connect

This work examines the properties of the manifold generated as the configuration space of the linkage used for each finger of the Salisbury hand. The authors begin with an exhaustive catalog of design types for the finger based on an analysis of its branch loci. They then study the conditions under which the forward kinematic map becomes singular. These singularities define a submanifold that partitions the linkage's configuration space into a number of open sheets, each of which maps diffeomorphically onto a corresponding open region in the finger's reachable work space. Next they consider the determinant function of the finger's Jacobian matrix. The stationary points of this function reveal those configurations where the Jacobian determinant is a maximum. The Jacobian determinant can be thought of as an oriented volume in the tangent space to the finger's work space, and the orientation of this volume reveals the most favorable direction(s) for effecting tip motion or, reciprocally, for applying tip forces. From this they establish a simple criterion that can be used to find the optimal grasp configuration(s) for a given finite displacement of the workpiece.

McAree, P.R.; Samuel, A.E.; Hunt, K.H. (Univ. of Melbourne, Parkville (Australia)); Gibson, C.G. (Univ. of Liverpool (United Kingdom))

1991-10-01

138

Real time markerless motion tracking using linked kinematic chains  

DOEpatents

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.

Luck, Jason P. (Arvada, CO); Small, Daniel E. (Albuquerque, NM)

2007-08-14

139

Magnetotelluric Inversion in a 2D Anisotropic Environment  

NASA Astrophysics Data System (ADS)

In recent years several authors have proposed algorithms to perform magnetotelluric (MT) inversion in a 3D environment. The development of high performance computer (hpc) machines allows the solution of these inverse problems in a reasonable time, nevertheless the solution of a 3D problem remains at the present extremely challenging. Moreover it is proofed that any magnitude of anisotropy possibly present in the subsurface conductivity can be modeled by a sufficient dense discretization of a 3D isotropic domain, keeping the recognition of intrinsically anisotropic bulks virtually impossible for a 3D code. These arguments convinced us to develop a 2D inverse code able in assessing anisotropy and running in an affordable time, testing several scenario for the same dataset in the same time in which a 3D inversion code produces its first model. In this work we report results from synthetic tests we performed. MT inverse problem is challenging because of several reasons. It is both highly non-linear, ill-conditioned and suffers of a severe non-uniqueness of the solution, therefore we developed an inversion algorithm based on the classic Levenberg-Marquardt (LM) strategy, minimizing the objective function (?-G-(m)-d)2 ?(m )= ? +?aLa +?sLs in which m is the model, G the forward operator, d the data vector, L* the regularization matrix and ?* the trade-off parameter for respectively anisotropy and structure. Usually LM method is used for medium size problems, mainly because it requires the explicit computation and storage of the Jacobian matrix J and the explicit knowledge of the product JTJ. To compute the Jacobian it has proofed that the electrical reciprocity theorem is a valuable tool, allowing to compute the full Jacobian with the evaluation of one forward problem per station in spite of one forward problem per parameter as usually done with the finite-difference method. Moreover the computation of the forward response can be easily performed in parallel, due the mutual independency of the different spectral components, storing the Jacobian in a distribute machine memory and solving at the same time the problem of the huge memory requirements used to store the product JTJ and speeding up the whole process. We performed tests on the simple synthetic model released with the code from Pek and Santos [2004]: an 84-100 cells grid, grouped in 3 up to 20 blocks sharing the same conductivities. Results proof the capacity of the algorithm in recovering the subsurface structure with good precision, reaching an RMS of the magnitude 10-5 for the 20 block case without the use of regularization. More tests will be presented and results highlighted.

Mandolesi, E.; Jones, A. G.

2012-04-01

140

Inverse Functions  

NSDL National Science Digital Library

Using Mathcad, Maple, Mathmatica, or MatLab, learner should be able to review concepts of inverse functions, and to use those concepts, together with functions defined by integrals, to develop inverse trigonometric functions.

Smith, David; Moore, Lawrence

2001-01-25

141

Resolving spectral information from time domain induced polarization data through 2-D inversion  

NASA Astrophysics Data System (ADS)

Field-based time domain (TD) induced polarization (IP) surveys are usually modelled by taking into account only the integral chargeability, thus disregarding spectral content. Furthermore, the effect of the transmitted waveform is commonly neglected, biasing inversion results. Given these limitations of conventional approaches, a new 2-D inversion algorithm has been developed using the full voltage decay of the IP response, together with an accurate description of the transmitter waveform and receiver transfer function. This allows reconstruction of the spectral information contained in the TD decay series. The inversion algorithm is based around a 2-D complex conductivity kernel that is computed over a range of frequencies and converted to the TD through a fast Hankel transform. Two key points in the implementation ensure that computation times are minimized. First, the speed of the Jacobian computation, time transformed from frequency domain through the same transformation adopted for the forward response is optimized. Secondly, the reduction of the number of frequencies where the forward response and Jacobian are calculated: cubic splines are used to interpolate the responses to the frequency sampling necessary in the fast Hankel transform. These features, together with parallel computation, ensure inversion times comparable with those of direct current algorithms. The algorithm has been developed in a laterally constrained inversion scheme, and handles both smooth and layered inversions; the latter being helpful in sedimentary environments, where quasi-layered models often represent the actual geology more accurately than smooth minimum-structure models. In the layered inversion approach, a general method to derive the thickness derivative from the complex conductivity Jacobian is also proposed. One synthetic example of layered inversion and one field example of smooth inversion show the capability of the algorithm and illustrates a complete uncertainty analysis of the model parameters. With this new algorithm, in situ TD IP measurements give access to the spectral content of the polarization processes, opening up new applications in environmental and hydrogeophysical investigations.

Fiandaca, Gianluca; Ramm, James; Binley, Andrew; Gazoty, Aurélie; Christiansen, Anders Vest; Auken, Esben

2013-02-01

142

Rotational kinematics influence multimodal perception of heaviness.  

PubMed

Perceived heaviness has been shown to be specific to an object's rotational inertia (I), its resistance to rotational acceleration. According to the kinematic specification of dynamics (KSD) principle, we hypothesized that I is optically specified by rotational kinematics. Using virtual depictions of wielded objects, we investigated whether the visually detected rotational kinematics of wielded objects would influence perceived heaviness in a manner consistent with the inertial model of heaviness perception. We scaled the virtual object's movement so that it rotated more or less than its wielded counterpart, specifying lower and higher I, respectively. Perceived heaviness was inversely related to the rotational scaling factor, consistent with a KSD interpretation of the inertial model. PMID:17694927

Streit, Matthew; Shockley, Kevin; Morris, Anthony W; Riley, Michael A

2007-04-01

143

A new approach for the geometrical calibration of parallel kinematics machines tools based on the machining of a dedicated part  

Microsoft Academic Search

A main limitation of parallel kinematics machine tools (PKM) in high-speed machining tasks is their low level of accuracy compared with serial kinematics machine tools, which is largely due to geometrical transformation errors. These errors can be reduced by identifying the geometrical parameters of the inverse kinematics model integrated in the controller by exteroceptive calibration. The aim of this paper

H. Chanal; E. Duc; P. Ray; J. Y. Hascoët

2007-01-01

144

Kinematics of an infinitely flexible robot arm  

Microsoft Academic Search

An effort is made to define a command-and-control algorithm for a flexible robot arm design which maximizes flexibility through its large number of degrees-of-freedom, in the manner of a 'tentacle'. Algorithms including both forward and inverse kinematics are developed for commanding smooth arm motions in the presence of obstacles, on the basis of Catmull-Rom splines and local radius-of-curvature commands to

P. J. Choi; J. A. Rice; J. C. Cesarone

1993-01-01

145

Kinematic Jump Processes For Monocular 3D Human Tracking  

Microsoft Academic Search

A major difficulty for 3D human body tracking from monocular image sequences is the near non-observability of kinematic degrees of freedom that generate motion in depth. For known link (body seg- ment) lengths, the strict non-observabilities reduce to twofold 'for- wards\\/backwards flipping' ambiguities for each link. These imply # links formal inverse kinematics solutions for the full model, and hence

Cristian Sminchisescu; Bill Triggs

2003-01-01

146

Jacobian and stiffness analysis of a novel class of six-DOF parallel minimanipulators  

SciTech Connect

The Jacobian and stiffness matrices of two types of novel, six-DOF parallel minimanipulators are derived. A minimanipulator consists of three inextensible limbs, each of which is driven by a two-DOF driver. Bilinear stepper motors are used as drivers in the first type minimanipulator, whereas five-bar linkages are used as drivers in the second type minimanipulator. All of the minimanipulator actuators are base-mounted. Inextensible limbs (and five-bar linkage drivers in the second type minimanipulator) improve positional resolution and stiffness of the minimanipulators in certain directions. It is shown that, at the central configuration, the stiffness matrix of the first type minimanipulator can be diagonalized (decoupled). It is also shown that the first type minimanipulator can be designed to possess direct or torsional isotropic stiffness properties. Moreover, guidelines for designing the drivers of the second type minimanipulator are established. 20 refs.

Tashmasebi, F. [National Aeronautics and Space Administration, Greenbelt, MD (United States). Goddard Space Flight Center; Tsai, Lung-Wen [Maryland Univ., College Park, MD (United States). Dept. of Mechanical Engineering

1992-08-01

147

Jacobian and stiffness analysis of a novel class of six-DOF parallel minimanipulators  

SciTech Connect

The Jacobian and stiffness matrices of two types of novel, six-DOF parallel minimanipulators are derived. A minimanipulator consists of three inextensible limbs, each of which is driven by a two-DOF driver. Bilinear stepper motors are used as drivers in the first type minimanipulator, whereas five-bar linkages are used as drivers in the second type minimanipulator. All of the minimanipulator actuators are base-mounted. Inextensible limbs (and five-bar linkage drivers in the second type minimanipulator) improve positional resolution and stiffness of the minimanipulators in certain directions. It is shown that, at the central configuration, the stiffness matrix of the first type minimanipulator can be diagonalized (decoupled). It is also shown that the first type minimanipulator can be designed to possess direct or torsional isotropic stiffness properties. Moreover, guidelines for designing the drivers of the second type minimanipulator are established. 20 refs.

Tashmasebi, F. (National Aeronautics and Space Administration, Greenbelt, MD (United States). Goddard Space Flight Center); Tsai, Lung-Wen (Maryland Univ., College Park, MD (United States). Dept. of Mechanical Engineering)

1992-01-01

148

Kinematics Graph Interpretation Project  

NSDL National Science Digital Library

The primary goal of the Kinematics Graphing Project is to investigate the ability of students to interpret kinematics graphs and to generate a set of suggestions for faculty teaching the subject. Evaluation instruments are used to uncover the common misconceptions of students.

Beichner, Robert J.

2003-10-10

149

Inverse Methods  

NASA Astrophysics Data System (ADS)

Over the last few decades inversion concepts have become an integral part of experimental data interpretation in several branches of science. In numerous cases similar inversion-like techniques were developed independently in separate disciplines, sometimes based on different lines of reasoning, but not always to the same level of sophistication. This book is based on the Interdisciplinary Inversion Conference held at the University of Aarhus, Denmark. For scientists and graduate students in geophysics, astronomy, oceanography, petroleum geology, and geodesy, the book offers a wide variety of examples and theoretical background in the field of inversion techniques.

Jacobsen, Bo Holm; Mosegaard, Klaus; Sibani, Paolo

150

Kinematic synthesis of bevel-gear-type robotic wrist mechanisms  

NASA Astrophysics Data System (ADS)

Bevel-gear-type robotic wrist mechanisms are commonly used in industry. The reasons for their popularity are that they are compact, light-weight, and relatively inexpensive. However, there are singularities in their workspace, which substantially degrade their manipulative performance. The objective of this research is to develop an atlas of three-degree-of-freedom bevel-gear-type wrist mechanisms, and through dimensional synthesis to improve their kinematic performance. The dissertation contains two major parts: the first is structural analysis and synthesis, the other is kinematic analysis and dimensional synthesis. To synthesize the kinematic structures of bevel-gear-type wrist mechanisms, the kinematic structures are separated from their functional considerations. All kinematic structures which satisfy the mobility condition are enumerated in an unbiased, systematic manner. Then the bevel-gear-type wrist mechanisms are identified by applying the functional requirements. Structural analysis shows that a three-degree-of-freedom wrist mechanism usually consists of non-fractionated, two degree-of-freedom epicyclic gear train jointed with the base link. Therefore, the structural synthesis can be simplified into a problem of examining the atlas of non-fractionated, two-degree-of-freedom epicyclic gear trains. The resulting bevel-gear-type wrist mechanism has been categorized and evaluated. It is shown that three-degree-of-freedom, four-jointed wrist mechanisms are promising for further improving the kinematic performance. It is found that a spherical planetary gear train is necessarily imbedded in a three-degree-of-freedom, four-jointed wrist mechanism. Therefore, to study the workspace and singularity problems of three-degree-of-freedom four-jointed spherical wrist mechanisms, we have to study the trajectories of spherical planetary gear trains. The parametric equations of the trajectories and some useful geometric properties for the analysis and synthesis of workplace are derived. The workspace boundary equations can be derived via both geometric consideration and Jacobian analysis. The workspace is divided by inner and outer boundaries into regions of accessibility of zero, two, and four. The design criteria of full workspace and a maximum four-root region are established. kinematic performance.

Lin, Chen-Chou

151

Kinematic calibration of gantry hybrid machine tool based on estimation error and local measurement information  

Microsoft Academic Search

This paper presents the kinematic calibration of a four degrees-of-freedom (DOF) hybrid machine tool based on a novel planar 3-DOFs parallel mechanism and a long movement of the worktable. Closed-form solutions are developed for both the inverse and direct kinematics about the parallel mechanism. The error model is built and the mechanism accuracy is investigated. Two types of kinematic calibration

Xiaoqiang Tang; Jinsong Wang; Men Gao

2005-01-01

152

KINEMATIC MODELLING AND SIMULATION OF A NOVEL INTERCONNECTED-CHAINS PKM  

Microsoft Academic Search

The paper deals with the conception and the kinematic modelling of a 5-degree-of-freedom Interconnected- Chains Parallel Kinematics Machine (IC-PKM). Usually parallel kinematics machines are composed of a platform connected in parallel to a fixed base by independent actuated serial chains. For this reason, the inverse position analysis is relatively trivial, while the direct position analysis is much more difficult. In

L. Bruzzone; R. Molfino; M. Zoppi

153

A comparison of the Gauss-Netwon and quasi-Newton methods in resistivity imaging inversion  

NASA Astrophysics Data System (ADS)

The smoothness-constrained least-squares method is widely used for two-dimensional (2D) and three-dimensional (3D) inversion of apparent resistivity data sets. The Gauss-Newton method that recalculates the Jacobian matrix of partial derivatives for all iterations is commonly used to solve the least-squares equation. The quasi-Newton method has also been used to reduce the computer time. In this method, the Jacobian matrix for a homogeneous earth model is used for the first iteration, and the Jacobian matrices for subsequent iterations are estimated by an updating technique. Since the Gauss-Newton method uses the exact partial derivatives, it should require fewer iterations to converge. However, for many data sets, the quasi-Newton method can be significantly faster than the Gauss-Newton method. The effectiveness of a third method that is a combination of the Gauss-Newton and quasi-Newton methods is also examined. In this combined inversion method, the partial derivatives are directly recalculated for the first two or three iterations, and then estimated by a quasi-Newton updating technique for the later iterations. The three different inversion methods are tested with a number of synthetic and field data sets. In areas with moderate (less than 10:1) subsurface resistivity contrasts, the inversion models obtained by the three methods are similar. In areas with large resistivity contrasts, the Gauss-Newton method gives significantly more accurate results than the quasi-Newton method. However, even for large resistivity contrasts, the differences in the models obtained by the Gauss-Newton method and the combined inversion method are small. As the combined inversion method is faster than the Gauss-Newton method, it represents a satisfactory compromise between speed and accuracy for many data sets.

Loke, M. H.; Dahlin, T.

2002-03-01

154

Nonlinear Inversion.  

National Technical Information Service (NTIS)

The long term goals of this research are to develop practical and efficient algorithms for application to the nonlinear inversion problems encountered in ocean acoustics. Such algorithms would be used for estimating or accounting for the effects of the en...

R. I. Odom

2010-01-01

155

Phenomenological study of irregular cellular automata based on Lyapunov exponents and Jacobians  

NASA Astrophysics Data System (ADS)

Originally, cellular automata (CA) have been defined upon regular tessellations of the n-dimensional Euclidean space, while CA on irregular tessellations have received only little attention from the scientific community, notwithstanding serious shortcomings are associated with the former manner of subdividing Rn. In this paper we present a profound phenomenological study of two-state, two-dimensional irregular CA from a dynamical systems viewpoint. We opted to exploit properly defined quantitative measures instead of resorting to qualitative methods for discriminating between behavioral classes. As such, we employ Lyapunov exponents, measuring the divergence rate of close trajectories in phase space, and Jacobians, formulated using Boolean derivatives and expressing the sensitivity of a cellular automaton to its inputs. Both are stated for two-state CA on irregular tessellations, enabling us to characterize these discrete dynamical systems, and advancing us to propose a classification scheme for this CA family. In addition, a relationship between these quantitative measures is established in extension of the insights already developed for the classical CA paradigm. Finally, we discuss the repercussions on the CA dynamics that arise when the geometric variability of the spatial entities is taken into account during the CA simulation.

Baetens, Jan M.; de Baets, Bernard

2010-09-01

156

Pelvis and torso kinematics and their relationship to shoulder kinematics in high-school baseball pitchers.  

PubMed

It was the purpose of our study to examine the kinematics of the pelvis and torso and determine their relationship to the kinematics of the shoulder in high-school baseball pitchers. A single group, repeated-measures design was used to collect pelvis, torso, and shoulder kinematics throughout the pitching motion. Subjects threw a series of maximal effort fastballs to a catcher located the regulation distance (18.44m) from the pitching mound, and those data from the fastest pitch passing through the strike zone were analyzed. After test trials, kinematic data were analyzed using a series of descriptive statistics to identify outliers and determine the nature of the distribution before testing for the presence of relationships between the various parameters. Results indicated that for several parameters, the actions at and about the shoulder are strongly related to the actions of the pelvis and torso throughout the pitching motion. However, although pelvis and torso kinematics throughout the pitching motion were inversely related to both shoulder elevation and the plane of shoulder elevation, only the rate of axial torso rotation was significantly related to these shoulder parameters. More importantly, the rate of axial torso rotation is significantly related to these shoulder parameters in a way that may help explain the high rate of shoulder injury in high-school pitchers. Therefore, strength training should focus on developing a strong stable core including the gluteal musculature in an attempt to control the rate of torso rotation during the pitch. PMID:20703168

Oliver, Gretchen D; Keeley, David W

2010-12-01

157

A dedicated solver for fast operational-space inverse dynamics  

Microsoft Academic Search

The most classical solution to generate whole-body motions on humanoid robots is to use the inverse kinematics on a set of tasks. It enables flexibility, repeatability, sensor-feedback if needed, and can be applied in real time onboard the robot. However, it cannot comprehend the whole complexity of the robot dynamics. Inverse dynamics is then a mandatory evolution. Before application as

N. Mansard

2012-01-01

158

Kinematic block model of Switzerland  

NASA Astrophysics Data System (ADS)

In 1997 swisstopo began to install and operate the Automated GPS Network for Switzerland (AGNES). Since then the network has been extended to more than 30 stations. From the time series swisstopo derives velocities which are used to create kinematic models of Switzerland under the assumption that the velocities correspond to the tectonic motion. However, one has to be aware of the very small crustal movements relative to the Eurasian plate. The expected velocities are in the range of 1 to 2 millimetres per year. Local influences like monumentation instability and landslides are not negligible and can bias the velocities significantly. For this purpose the time series were initially analysed for common mode effects and seasonal movements using stacking methods. Additional information from the Tectonic Map of Switzerland, published by swisstopo, helps to delimitate regions belonging to the same with kinematic pattern. The area covering the whole country has been separated into several blocks namely Jura, Basin, Prealps, and Alps. The movements of the blocks were determined by robust estimation, thus reducing the influence of velocities biased by local effects. During this process several stations had to be eliminated by reducing their weight in the inversion. The individual blocks were modelled by the assumption of rigid body dynamics. Two translations and one rotation about the Z-axis have been introduced for the horizontal movements. The vertical velocities are analysed separately using the same block assignments. The unknowns for each vertical block movement are one translation and two rotations about the X- and Y-axis. The block model gives a good first approximation of the tectonic deformation in Switzerlan

Villiger, Arturo; Geiger, Alain; Brockmann, Elmar

2010-05-01

159

Kinematics: Speed, Velocity & Acceleration  

NSDL National Science Digital Library

The following resource is a NFL sponsored, National Science Foundation funded program intended to teach students about scientific concepts by using the popular sport of Football. Each lesson is accompanied by an informative and fast paced video. In this lesson, students will explore kinematics on the playing field. NSF-funded scientists Tony Schmitz from the University of Florida and John Ziegert of Clemson University explain how the kinematic concepts of position, velocity and acceleration can be used to define how a running back moves.

2010-01-01

160

Kinematics of deformable media  

SciTech Connect

We investigate the kinematics of deformations in two and three dimensional media by explicitly solving (analytically) the evolution equations (Raychaudhuri equations) for the expansion, shear and rotation associated with the deformations. The analytical solutions allow us to study the dependence of the kinematical quantities on initial conditions. In particular, we are able to identify regions of the space of initial conditions that lead to a singularity in finite time. Some generic features of the deformations are also discussed in detail. We conclude by indicating the feasibility and utility of a similar exercise for fluid and geodesic flows in a flat and curved spacetimes.

Dasgupta, Anirvan [Department of Mechanical Engineering and Centre for Theoretical Studies, Indian Institute of Technology, Kharagpur 721 302 (India)], E-mail: anir@mech.iitkgp.ernet.in; Nandan, Hemwati [Centre for Theoretical Studies, Indian Institute of Technology, Kharagpur 721 302 (India)], E-mail: hnandan@cts.iitkgp.ernet.in; Kar, Sayan [Department of Physics and Centre for Theoretical Studies, Indian Institute of Technology, Kharagpur 721 302 (India)], E-mail: sayan@cts.iitkgp.ernet.in

2008-07-15

161

Kinemetry: quantifying kinematic maps  

NASA Astrophysics Data System (ADS)

With the development of integral field spectroscopy, our knowledge of the kinematic properties of stars in early-type galaxies is not restricted any more to their minor and major axes alone, but covers their whole extent. However, existing analysis tools are not well suited for this new kind of data. If we want to go beyond producing colorful maps, we have therefore to develop new analysis tools. In this context, I have been working on an extension of technics used in photometry to kinematic maps. I will present this new technic, the kinemetry, and its application to data obtained with the panoramic integral field spectrograph SAURON.

Copin, Yannick; Bacon, R.; Bureau, M.; Davies, R. L.; Emsellem, E.; Kuntschner, H.; Miller, B.; Peletier, R.; Verolme, E. K.; de Zeeuw, P. T.

2001-05-01

162

AVO inversion in V (x;z) media  

Microsoft Academic Search

We implement a new Kirchho-t yped AVO inversion scheme in V (x;z) media. The WKBJ Green's function is calculated using a nite-dierence scheme. We propose a pair of Kirchho inversion operators which have more obvious physical meaning. By analyzing the Kirchho inversion operator, we nd out an unique relationship between the weighting function and the kinematic equation, which is very

Yalei Sun; Wenjie Dong

1998-01-01

163

Kinematics of Tape Recording.  

ERIC Educational Resources Information Center

Describes mathematics of the nonliner relationships between a constant-speed, capstan-driven magnetic tape transport mechanism and a constant-angular-velocity take-up reel. The relationship, derived from the sum of a partial, serves in recognition of a finite tape. Thickness can serve as an example of rotational kinematics. (Author/SK)

Coleman, J. J.

1982-01-01

164

Teaching about Kinematics  

ERIC Educational Resources Information Center

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…

Nelson, Jane Bray; Nelson, Jim

2009-01-01

165

Teaching about Kinematics  

ERIC Educational Resources Information Center

|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…

Nelson, Jane Bray; Nelson, Jim

2009-01-01

166

Jacobian-free Newton Krylov discontinuous Galerkin method and physics-based preconditioning for nuclear reactor simulations  

SciTech Connect

We present high-order accurate spatiotemporal discretization of all-speed flow solvers using Jacobian-free Newton Krylov framework. One of the key developments in this work is the physics-based preconditioner for the all-speed flow, which makes use of traditional semi-implicit schemes. The physics-based preconditioner is developed in the primitive variable form, which allows a straightforward separation of physical phenomena. Numerical examples demonstrate that the developed preconditioner effectively reduces the number of the Krylov iterations, and the efficiency is independent of the Mach number and mesh sizes under a fixed CFL condition.

HyeongKae Park; Robert R. Nourgaliev; Richard C. Martineau; Dana A. Knoll

2008-09-01

167

Indirect inversions  

NASA Astrophysics Data System (ADS)

Since Doug MacAyeal's pioneering studies of the ice-stream basal traction optimizations by control methods, inversions for unknown parameters (e.g., basal traction, accumulation patterns, etc) have become a hallmark of the present-day ice-sheet modeling. The common feature of such inversion exercises is a direct relationship between optimized parameters and observations used in the optimization procedure. For instance, in the standard optimization for basal traction by the control method, ice-stream surface velocities constitute the control data. The optimized basal traction parameters explicitly appear in the momentum equations for the ice-stream velocities (compared to the control data). The inversion for basal traction is carried out by minimization of the cost (or objective, misfit) function that includes the momentum equations facilitated by the Lagrange multipliers. Here, we build upon this idea, and demonstrate how to optimize for parameters indirectly related to observed data using a suite of nested constraints (like Russian dolls) with additional sets of Lagrange multipliers in the cost function. This method opens the opportunity to use data from a variety of sources and types (e.g., velocities, radar layers, surface elevation changes, etc.) in the same optimization process.

Sergienko, Olga

2013-04-01

168

Generalized Quantum Relativistic Kinematics:  

NASA Astrophysics Data System (ADS)

We apply Lie algebra deformation theory to the problem of identifying the stable form of the quantum relativistic kinematical algebra. As a warm up, given Galileo's conception of spacetime as input, some modest computer code we wrote zeroes in on the Poincaré-plus-Heisenberg algebra in about a minute. Further ahead, along the same path, lies a three-dimensional deformation space, with an instability double cone through its origin. We give physical as well as geometrical arguments supporting our view that moment, rather than position operators, should enter as generators in the Lie algebra. With this identification, the deformation parameters give rise to invariant length and mass scales. Moreover, standard quantum relativistic kinematics of massive, spinless particles corresponds to non-commuting moment operators, a purely quantum effect that bears no relation to spacetime non-commutativity, in sharp contrast to earlier interpretations.

Chryssomalakos, C.; Okon, E.

169

Kinematic strain localization  

NASA Astrophysics Data System (ADS)

Deformation within a steady-state compressional orogen, i.e., where tectonic accretion is, on geological time scales, balanced by surface erosion, can best be described by a stationary velocity field. Instantaneous deformation results from spatial gradients in the velocity field, whereas total accumulated strain results from the integration of this instantaneous deformation along material paths following the flow lines defined by the velocity field. We have synthesized the net strain distributions for rocks exposed at the surface of such an orogenic system using simple, linear velocity fields corresponding to (a) simple shear within a dipping shear zone and (b) pure vertical shear. In both cases we demonstrate the development of surface patterns of finite strain accumulation that do not reflect the geometry of the assumed velocity field in a simple manner. Large gradients in finite strain arise as a consequence of the geographic variation in particle residence time imposed by the surface boundary, even for the limiting case where no instantaneous strain gradient exists. Such patterns of deformation are often recognised in exhumed orogenic systems, but have commonly been assumed to reflect more complex velocity fields resulting from nonlinear, localizing crustal rheologies. We therefore demonstrate that caution should be exercised in interpreting observed strain patterns because a proportion of the observed strain localization must be attributed to this purely kinematic (or geometric) effect — and this proportion may be significant in many systems. Such kinematic effects should be quantified, and subtracted from observed strain distributions before they are used to infer the rheological behavior of crustal rocks. We also suggest that in a simple shear (thrust) setting, kinematic strain localization may in fact nucleate strain softening on the side of the deforming region that is stable or fixed with respect to the Earth's surface and thus be responsible for the asymmetry that characterizes the large majority of thrust systems.

Braun, Jean; Herman, Frédéric; Batt, Geoffrey

2010-12-01

170

Network configuration and hydrograph sensitivity to storm kinematics  

NASA Astrophysics Data System (ADS)

This paper explores the relationship between channel network configurations and hydrograph sensitivity to storm kinematics with different storm speeds, storm directions, and storm sizes. A synthetic circular catchment is introduced, in order to prevent bias due to interaction between storm directions and catchment geometry. The drainage network of the test catchment is simulated with Gibbs' model for a given network configuration (?). The peak response of the catchment is investigated with different configurations of drainage network, combined with different conditions of storm kinematics. The results show that the relationship between storm kinematics and the peak discharge response is dependent on the network configuration. The network configuration indicates the network efficiency in terms of the total drainage time of a network. The resonance condition can be defined for a 2-D drainage network as the inverse of the averaged total sum of flow distance. The results show that the storm kinematics that produces the maximum peak discharge depends on the network configuration because the resonance condition changes with the network configuration. The investigation of 12 catchments in the Chicago area indicates that urban drainage networks, typically, are highly efficient but can also be inefficient. The results illustrate that more inefficient networks (networks with lower ?) are less sensitive to rainstorm movement and produce lower peak discharge, compared with efficient networks. In contrast, an efficient network produces higher peak discharges and is more sensitive to storm kinematics, compared with an inefficient network.

Seo, Yongwon; Schmidt, Arthur R.

2013-04-01

171

Comparison of iterative methods and preconditioners for two-phase flow in porous media using exact and approximate Jacobians  

NASA Astrophysics Data System (ADS)

Two-phase flow in porous media occurs in various settings, such as the sequestration of CO2 in the subsurface, radioactive waste management, the flow of oil or gas in hydrocarbon reservoirs, or groundwater remediation. To model the sequestration of CO2, we consider a fully coupled formulation of the system of nonlinear, partial differential equations. For the solution of this system, we employ the Box method after Huber & Helmig (2000) for the space discretization and the fully implicit Euler method for the time discretization. After linearization with Newton's method, it remains to solve a linear system in every Newton step. We compare different iterative methods (BiCGStab, GMRES, AGMG, c.f., [Notay (2012)]) combined with different preconditioners (ILU0, ASM, Jacobi, and AMG as preconditioner) for the solution of these systems. The required Jacobians can be obtained elegantly with automatic differentiation (AD) [Griewank & Walther (2008)], a source code transformation providing exact derivatives. We compare the performance of the different iterative methods with their respective preconditioners for these linear systems. Furthermore, we analyze linear systems obtained by approximating the Jacobian with finite differences in terms of Newton steps per time step, steps of the iterative solvers and the overall solution time. Finally, we study the influence of heterogeneities in permeability and porosity on the performance of the iterative solvers and their robustness in this respect. References [Griewank & Walther(2008)] Griewank, A. & Walther, A., 2008. Evaluating Derivatives: Principles and Techniques of Algorithmic Differentiation, SIAM, Philadelphia, PA, 2nd edn. [Huber & Helmig(2000)] Huber, R. & Helmig, R., 2000. Node-centered finite volume discretizations for the numerical simulation of multiphase flow in heterogeneous porous media, Computational Geosciences, 4, 141-164. [Notay(2012)] Notay, Y., 2012. Aggregation-based algebraic multigrid for convection-diffusion equations, SIAM Journal on Scientific Computing, 34, A2288-A2316.

Büsing, Henrik

2013-04-01

172

Improving the numerical convergence of viscous-plastic sea ice models with the Jacobian-free Newton-Krylov method  

NASA Astrophysics Data System (ADS)

We have implemented the Jacobian-free Newton-Krylov (JFNK) method to solve the sea ice momentum equation with a viscous-plastic (VP) formulation. The JFNK method has many advantages: the system matrix (the Jacobian) does not need to be formed and stored, the method is parallelizable and the convergence can be nearly quadratic in the vicinity of the solution. The convergence rate of our JFNK implementation is characterized by two phases: an initial phase with slow convergence and a fast phase for which the residual norm decreases significantly from one Newton iteration to the next. Because of this fast phase, the computational gain of the JFNK method over the standard solver used in existing VP models increases with the required drop in the residual norm (termination criterion). The JFNK method is between 3 and 6.6 times faster (depending on the spatial resolution and termination criterion) than the standard solver using a preconditioned generalized minimum residual method. Resolutions tested in this study are 80, 40, 20 and 10 km. For a large required drop in the residual norm, both JFNK and standard solvers sometimes do not converge. The failure rate for both solvers increases as the grid is refined but stays relatively small (less than 2.3% of failures). With increasing spatial resolution, the velocity gradients (sea ice deformations) get more and more important. Nonlinear solvers such as the JFNK method tend to have difficulties when there are such sharp structures in the solution. This lack of robustness of both solvers is however a debatable problem as it mostly occurs for large required drops in the residual norm. Furthermore, when it occurs, it usually affects only a few grid cells, i.e., the residual is small for all the velocity components except in very localized regions. Globalization approaches for the JFNK solver, such as the line search method, have not yet proven to be successful. Further investigation is needed.

Lemieux, Jean-François; Tremblay, Bruno; Sedlá?ek, Jan; Tupper, Paul; Thomas, Stephen; Huard, David; Auclair, Jean-Pierre

2010-04-01

173

Simple kinematic gait measurements.  

PubMed

Simple kinematic gait measurement equipment was developed providing fast and inexpensive clinical gait analysis. Such a simple system can be used as a stand-alone clinical gait analyser, or as an accessory for measurements whose results are not sufficiently weighted statistically, such as TV, Selspot, force plate. Time, distance and velocity parameters are included in the clinical gait analysis. Time parameters (step and stride time, swing and stance phase) are measured via easily attachable foot-switches. Analog and digital versions were developed to analyse distance (stride and step length) and velocity (instantaneous velocity of centre of gravity) parameters. With the analog device the velocity is measured by tachometer and distance by potentiometer, while using digital methods, both parameters can be obtained from an optical transducer. PMID:7374117

Bajd, T; Kralj, A

1980-04-01

174

Inverse dynamics of a planetary gear train for robotics  

Microsoft Academic Search

Recursive matrix relations concerning the geometric analysis, kinematics and dynamics of a Bendix wrist planetary bevel-gear train for robotics are established in the paper. The prototype of this mechanism is a 3-DOF system with seven links and four bevel gear pairs controlled by electric motors. Supposing that the rotational motion of the platform is known, an inverse dynamic problem is

Stefan Staicu

2008-01-01

175

Fault-Tolerant Structured Adaptive Model Inversion Control  

Microsoft Academic Search

An adaptive dynamic inversion control formulation is presented that takes advantage of the inherent dynamic structure of the state-space description of a large class of systems. The formulations impose the exact kinematic differential equations, thereby restricting the adaptation process that compensates for model errors to the accel- eration level. The utility of this formulation is demonstrated for the problem of

Monish D. Tandale; John Valasek

2006-01-01

176

A parallel algorithm and architecture for the control of kinematically redundant manipulators  

SciTech Connect

Kinematically redundant manipulators are inherently capable of more dexterous manipulation due to their additional degrees of freedom. To achieve this dexterity, however, one must be able to efficiently calculate the most desirable configuration from the infinite number of possible configurations that satisfy the end-effector constraint. It has been previously shown that the singular value decomposition (SVD) plays a crucial role in doing such calculations. In this work, a parallel algorithm for calculating the SVD is incorporated into a computational scheme for solving the equations of motion for kinematically redundant systems. This algorithm, which generalizes the damped least squares formulation to include solutions that utilize null-space projections and task prioritization as well as augmented or extended Jacobians, is then implemented on a simple linear array of processing elements. By taking advantage of the error bounds on the perturbation of the SVD, it is shown that an array of only four AT T DSP chips can result in control cycle times of less than 3 ms for a seven degree-of-freedom manipulator.

Maciejewski, A.A. (Purdue Univ., West Lafayette, IN (United States). School of Electrical Engineering); Reagin, J.M. (General Motors, Anderson, IN (United States). Inland Fisher Guide Division)

1994-08-01

177

Notes on Kinematics/Motion  

NSDL National Science Digital Library

This outline of kinematics, the introduction to a PTRA manual, provides an approach to teaching the material. It includes activities, discussion questions, and other resources for presenting this material.

Nelson, Jim; Nelson, Jane

2004-11-10

178

Symmetric Inverse Consistent Nonlinear Registration Driven by Mutual Information  

PubMed Central

A nonlinear viscoelastic image registration algorithm based on the demons paradigm and incorporating inverse consistent constraint (ICC) is implemented. An inverse consistent and symmetric cost function using mutual information as a similarity measure is employed. The cost function also includes regularization of transformation and inverse consistent error (ICE). The uncertainties in balancing various terms in the cost function are avoided by alternatively minimizing the similarity measure, the regularization of the transformation, and the ICE terms. The diffeomorphism of registration for preventing folding and/or tearing in the deformation is achieved by the composition scheme. The quality of image registration is first demonstrated by constructing brain atlas from 20 adult brains (age range 30 to 60). It is shown that with this registration technique: 1) the Jacobian determinant is positive for all voxels and 2) the average ICE is around 0.004 voxels with a maximum value below 0.1 voxel. Further, the deformation based segmentation on Internet Brain Segmentation Repository, a publicly available dataset, has yielded high Dice similarity index (DSI) of 94.7% for the cerebellum and 74.7% for the hippocampus, attesting to the quality of our registration method.

Tao, Guozhi; He, Renjie; Datta, Sushmita; Narayana, Ponnada A.

2009-01-01

179

Paracentric inversions: a review  

Microsoft Academic Search

This review of paracentric inversions in man includes what we know of the behaviour and reproductive consequences of paracentric inversions from other species. Observations of naturally occurring inversions in several species of plants and animals and results of experiments with mutagenically induced inversions in the mouse are discussed. From a review of 184 cases, it is concluded that most of

K. Madan

1995-01-01

180

Tracking lung tissue motion and expansion/compression with inverse consistent image registration and spirometry  

SciTech Connect

Breathing motion is one of the major limiting factors for reducing dose and irradiation of normal tissue for conventional conformal radiotherapy. This paper describes a relationship between tracking lung motion using spirometry data and image registration of consecutive CT image volumes collected from a multislice CT scanner over multiple breathing periods. Temporal CT sequences from 5 individuals were analyzed in this study. The couch was moved from 11 to 14 different positions to image the entire lung. At each couch position, 15 image volumes were collected over approximately 3 breathing periods. It is assumed that the expansion and contraction of lung tissue can be modeled as an elastic material. Furthermore, it is assumed that the deformation of the lung is small over one-fifth of a breathing period and therefore the motion of the lung can be adequately modeled using a small deformation linear elastic model. The small deformation inverse consistent linear elastic image registration algorithm is therefore well suited for this problem and was used to register consecutive image scans. The pointwise expansion and compression of lung tissue was measured by computing the Jacobian of the transformations used to register the images. The logarithm of the Jacobian was computed so that expansion and compression of the lung were scaled equally. The log-Jacobian was computed at each voxel in the volume to produce a map of the local expansion and compression of the lung during the breathing period. These log-Jacobian images demonstrate that the lung does not expand uniformly during the breathing period, but rather expands and contracts locally at different rates during inhalation and exhalation. The log-Jacobian numbers were averaged over a cross section of the lung to produce an estimate of the average expansion or compression from one time point to the next and compared to the air flow rate measured by spirometry. In four out of five individuals, the average log-Jacobian value and the air flow rate correlated well (R{sup 2}=0.858 on average for the entire lung). The correlation for the fifth individual was not as good (R{sup 2}=0.377 on average for the entire lung) and can be explained by the small variation in tidal volume for this individual. The correlation of the average log-Jacobian value and the air flow rate for images near the diaphragm correlated well in all five individuals (R{sup 2}=0.943 on average). These preliminary results indicate a strong correlation between the expansion/compression of the lung measured by image registration and the air flow rate measured by spirometry. Predicting the location, motion, and compression/expansion of the tumor and normal tissue using image registration and spirometry could have many important benefits for radiotherapy treatment. These benefits include reducing radiation dose to normal tissue, maximizing dose to the tumor, improving patient care, reducing treatment cost, and increasing patient throughput.

Christensen, Gary E.; Song, Joo Hyun; Lu, Wei; Naqa, Issam El; Low, Daniel A. [Department of Electrical and Computer Engineering and Department of Radiation Oncology, University of Iowa, Iowa City, Iowa 52242 (United States); Department of Electrical and Computer Engineering, University of Iowa, Iowa City, Iowa 52242 (United States); Department of Radiation Oncology, Mallinckrodt Institute of Radiology, Washington University School of Medicine, St. Louis, Missouri 63110 (United States)

2007-06-15

181

Effect of the Ankle Stabilizing Orthosis on Foot and Ankle Kinematics During Cutting Maneuvers  

Microsoft Academic Search

This study was to examine the stability and functionality of the Ankle Stabilizing Orthosis (ASO) in normal ankle kinematics during sideward and forward lateral cutting. Fifteen college students with normal ankles were randomly assigned to each of the following four conditions: sideward and forward lateral cutting, with and without the ASO. Ankle inversion–eversion and dorsiflexion–plantarflexion angular displacements and velocities during

Amisha Gudibanda; Yong “Tai” Wang

2005-01-01

182

Inverse modeling of the global methyl chloride sources  

NASA Astrophysics Data System (ADS)

Inverse modeling using the Bayesian least squares method is applied to better constrain the sources and sinks of atmospheric methyl chloride (CH3Cl) using observations from seven surface stations and eight aircraft field experiments. We use a three-dimensional global chemical transport model, the GEOS-Chem, as the forward model. Up to 39 parameters describing the continental/hemispheric and seasonal dependence of the major sources of CH3Cl are used in the inversion. We find that the available surface and aircraft observations cannot constrain all the parameters, resulting in relatively large uncertainties in the inversion results. By examining the degrees of freedom in the inversion Jacobian matrix, we choose a reduced set of parameters that can be constrained by the observations while providing valuable information on the sources and sinks. In particular, we resolve the seasonal dependence of the biogenic and biomass-burning sources for each hemisphere. The in situ aircraft measurements are found to provide better constraints on the emission sources than surface measurements. The a posteriori emissions result in better agreement with the observations, particularly at southern high latitudes. The a posteriori biogenic and biomass-burning sources decrease by 13 and 11% to 2500 and 545 Gg yr-1, respectively, while the a posteriori net ocean source increases by about a factor of 2 to 761 Gg yr-1. The decrease in biomass-burning emissions is largely due to the reduction in the emissions in seasons other than spring in the Northern Hemisphere. The inversion results indicate that the biogenic source has a clear winter minimum in both hemispheres, likely reflecting the decrease of biogenic activity during that season.

Yoshida, Yasuko; Wang, Yuhang; Shim, Changsub; Cunnold, Derek; Blake, Donald R.; Dutton, Geoffrey S.

2006-08-01

183

Observation of the Inverse Doppler Effect  

NASA Astrophysics Data System (ADS)

We report experimental observation of an inverse Doppler shift, in which the frequency of a wave is increased on reflection from a receding boundary. This counterintuitive effect has been produced by reflecting a wave from a moving discontinuity in an electrical transmission line. Doppler shifts produced by this system can be varied in a reproducible manner by electronic control of the transmission line and are typically five orders of magnitude greater than those produced by solid objects with kinematic velocities. Potential applications include the development of tunable and multifrequency radiation sources.

Seddon, N.; Bearpark, T.

2003-11-01

184

Deformable templates using large deformation kinematics  

Microsoft Academic Search

A general automatic approach is presented for accommodating local shape variation when mapping a two-dimensional (2-D) or three-dimensional (3-D) template image into alignment with a topologically similar target image. Local shape variability is accommodated by applying a vector-field transformation to the underlying material coordinate system of the template while constraining the transformation to be smooth (globally positive definite Jacobian). Smoothness

Gary E. Christensen; Richard D. Rabbitt; Michael I. Miller

1996-01-01

185

Anthropometry and Kinematics in Crew Station Design.  

National Technical Information Service (NTIS)

Attention to the anthropometric and kinematic characteristics of the aircrew member is essential to good cockpit design. The design problems are many in which anthropometric and kinematic variability must be accommodated. Many are crucial to the safety of...

K. W. Kennedy

1973-01-01

186

The kinematics of multi-fingered manipulation  

Microsoft Academic Search

In this paper, we derive a configuration-space description of the kinematics of the fingers-plus-object system. To do this, we first formulate contact kinematics as a “virtual” kinematic chain. Then, the system can be viewed as one large closed kinematic chain composed of smaller chains, one for each finger and one for each contact point. We examine the underlying configuration space

David J. Montana

1995-01-01

187

Kinematics of the western Mediterranean  

Microsoft Academic Search

I I SUMMARY: The kinematic understanding of the relationship between relative plate motion and the structure of orogenic belts depends upon a knowledge of relative plate motion across the plate boundary system, the relative motion of small blocks and flakes within the system, an evaluation of orogenic body forces, and an understanding of the thermomechanical evolution of the upper part

J. F. Dewey; M. L. Helman; S. D. Knott; E. Turco; D. H. W. Hutton

1989-01-01

188

Kinematic theory of piezoelectric hysteresis  

Microsoft Academic Search

A biasing voltage applied across a bonded piezoelectric plate causes a transverse deflection. For slowly varying voltages, the displacement shows a characteristic hysteresis. A kinematic model is proposed which relates nonlinearly the displacement and its rate to the applied voltage. The analysis is developed to account quantitatively for the measured quasistatic hysteresis and decay, and to predict resonant dynamical effects.

P. G. Harper

1981-01-01

189

Kinematic Dexterity of Robotic Mechanisms  

Microsoft Academic Search

In this article we develop a mathematical theory for optimizing the kinematic dexterity of robotic mechanisms and obtain a collection of analytical tools for robot design. The performance criteria we consider are workspace volume and dexterity; by the latter we mean the ability to move and apply forces in arbitrary directions as easily as possible. Clearly, dexterity and workspace volume

Frank C. Park; Roger W. Brockett

1994-01-01

190

Influence of kinematic analysis methods on detecting ankle and subtalar joint instability.  

PubMed

Patients with subtalar joint instability may be misdiagnosed with ankle instability, which may lead to chronic instability at the subtalar joint. Therefore, it is important to understand the difference in kinematics after ligament sectioning and differentiate the changes in kinematics between ankle and subtalar instability. Three methods may be used to determine the joint kinematics; the Euler angles, the Joint Coordinate System (JCS) and the helical axis (HA). The purpose of this study was to investigate the influence of using either method to detect subtalar and ankle joints instability. 3D kinematics at the ankle and subtalar joint were analyzed on 8 cadaveric specimens while the foot was intact and after sequentially sectioning the anterior talofibular ligament (ATFL), the calcaneofibular ligament (CFL), the cervical ligament and the interosseous talocalcaneal ligament (ITCL). Comparison in kinematics calculated from sensor and anatomical landmarks was conducted as well as the influence of Euler angles and JCS rotation sequence (between ISB recommendation and previous research) on the subtalar joint. All data showed a significant increase in inversion when the ITCL was sectioned. There were differences in the data calculated using sensors coordinate systems vs. anatomic coordinate systems. Anatomic coordinate systems were recommended for these calculations. The Euler angle and JCS gave similar results. Differences in Euler angles and JCS sequence lead to the same conclusion in detecting instability at the ankle and subtalar joint. As expected, the HA detected instability in plantarflexion at the ankle joint and in inversion at the subtalar joint. PMID:22056198

Choisne, Julie; Ringleb, Stacie I; Samaan, Michael A; Bawab, Sebastian Y; Naik, Dayanand; Anderson, Claude D

2011-11-03

191

Joint kinematics simulation from medical imaging data  

Microsoft Academic Search

A method for joint kinematics simulation is described. Kinematics parameters are determined from the relative displacement of marker sets placed on anatomical landmarks of surface models generated from medical imaging contour data. The landmarks are identified manually on fingers in multiple positions. A mathematical algorithm was then used to ascertain the kinematics axes of motion of the fingers. Once these

Serge Van Sint Jan; David J. Giurintano; David E. Thompson; Marcel Rooze

1997-01-01

192

Kinematic solution of spherical Stephenson-III six-bar mechanism  

NASA Astrophysics Data System (ADS)

A closed-form solution can be obtained for kinematic analysis of spatial mechanisms by using analytical method. However, extra solutions would occur when solving the constraint equations of mechanism kinematics unless the constraint equations are established with a proper method and the solving approach is appropriate. In order to obtain a kinematic solution of the spherical Stephenson-III six-bar mechanism, spherical analytical theory is employed to construct the constraint equations. Firstly, the mechanism is divided into a four-bar loop and a two-bar unit. On the basis of the decomposition, vectors of the mechanism nodes are derived according to spherical analytical theory and the principle of coordinate transformation. Secondly, the structural constraint equations are constructed by applying cosine formula of spherical triangles to the top platform of the mechanism. Thirdly, the constraint equations are solved by using Bezout's elimination method for forward analysis and Sylvester's resultant elimination method for inverse kinematics respectively. By the aid of computer symbolic systems, Mathematica and Maple, symbolic closed-form solution of forward and inverse displacement analysis of spherical Stephenson-III six-bar mechanism are obtained. Finally, numerical examples of forward and inverse analysis are presented to illustrate the proposed approach. The results indicate that the constraint equations established with the proposed method are much simpler than those reported by previous literature, and can be readily eliminated and solved.

Liu, Yanfang; Yang, Suixian

2013-09-01

193

Kinematic and stability motion limits for a hexapod walking machine  

NASA Astrophysics Data System (ADS)

The major problem addressed by this research is to investigate and implement the basic concepts necessary to lay the groundwork for efficient forms of motion planning, motion control, and gait algorithms with respect to hexapod walking machines. Specifically, the approach taken was to develop and implement the concepts of a stability margin and a joint space motion margin on an object-oriented representation of the Aquarobot. The model was generated in Franz Common Lisp and simulated via Allegro Common Windows. A method by which distance computations can be calculated and applied to the center of mass and triangular support pattern of a walking machine to determine the stability margin is introduced. Inverse kinematics and joint limits are utilized to ascertain the joint space motion margin of the model. Response to impending instability and the effect when a joint hits or approaches a joint kinematic limit on the motion of the hexapod walking machine by stopping the model is also addressed. The results are as follows: the concepts of the joint space motion margin and the stability margin can be successfully implemented on a kinematic model and graphical simulation of a hexapod walking machine. These concepts contribute to future work in the area of more efficient free gait algorithms, specifically asynchronous gait algorithms.

Dunton, Elizabeth M.

1995-03-01

194

Inversion of high frequency surface waves with fundamental and higher modes  

USGS Publications Warehouse

The phase velocity of Rayleigh-waves of a layered earth model is a function of frequency and four groups of earth parameters: compressional (P)-wave velocity, shear (S)-wave velocity, density, and thickness of layers. For the fundamental mode of Rayleigh waves, analysis of the Jacobian matrix for high frequencies (2-40 Hz) provides a measure of dispersion curve sensitivity to earth model parameters. S-wave velocities are the dominant influence of the four earth model parameters. This thesis is true for higher modes of high frequency Rayleigh waves as well. Our numerical modeling by analysis of the Jacobian matrix supports at least two quite exciting higher mode properties. First, for fundamental and higher mode Rayleigh wave data with the same wavelength, higher modes can "see" deeper than the fundamental mode. Second, higher mode data can increase the resolution of the inverted S-wave velocities. Real world examples show that the inversion process can be stabilized and resolution of the S-wave velocity model can be improved when simultaneously inverting the fundamental and higher mode data. ?? 2002 Elsevier Science B.V. All rights reserved.

Xia, J.; Miller, R. D.; Park, C. B.; Tian, G.

2003-01-01

195

A "voice inversion effect?".  

PubMed

Voice is the carrier of speech but is also an "auditory face" rich in information on the speaker's identity and affective state. Three experiments explored the possibility of a "voice inversion effect," by analogy to the classical "face inversion effect," which could support the hypothesis of a voice-specific module. Experiment 1 consisted of a gender identification task on two syllables pronounced by 90 speakers (boys, girls, men, and women). Experiment 2 consisted of a speaker discrimination task on pairs of syllables (8 men and 8 women). Experiment 3 consisted of an instrument discrimination task on pairs of melodies (8 string and 8 wind instruments). In all three experiments, stimuli were presented in 4 conditions: (1) no inversion; (2) temporal inversion (e.g., backwards speech); (3) frequency inversion centered around 4000 Hz; and (4) around 2500 Hz. Results indicated a significant decrease in performance caused by sound inversion, with a much stronger effect for frequency than for temporal inversion. Interestingly, although frequency inversion markedly affected timbre for both voices and instruments, subjects' performance was still above chance. However, performance at instrument discrimination was much higher than for voices, preventing comparison of inversion effects for voices vs. non-vocal stimuli. Additional experiments will be necessary to conclude on the existence of a possible "voice inversion effect." PMID:15177788

Bédard, Catherine; Belin, Pascal

2004-07-01

196

Kinematic Fitting of Detached Vertices  

SciTech Connect

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.

Paul Mattione

2007-05-01

197

Science of NHL Hockey: Kinematics  

NSDL National Science Digital Library

NHL skaters can reach speeds in excess of 20 miles (32km) per hour, and during some short bursts approach 30 miles (48 km) per hour. Kinematics, the branch of classical mechanics, helps describe a player's movement across the ice by defining his position, velocity and acceleration. "Science of NHL Hockey" is a 10-part video series produced in partnership with the National Science Foundation and the National Hockey League.

Learn, Nbc

2010-10-07

198

Kinematic and dynamic synergies of human precision-grip movements.  

PubMed

We analyzed the adaptability of human thumb and index finger movement kinematics and dynamics to variations of precision grip aperture and movement velocity. Six subjects performed precision grip opening and closing movements under different conditions of movement velocity and movement aperture (thumb and index finger tip-to-tip distance). Angular motion of the thumb and index finger joints was recorded with a CyberGlove and a three-dimensional biomechanical model was used for solving the inverse dynamics problem during precision grip movements, i.e., for calculating joint torques from experimentally obtained angular variations. The time-varying joint angles and joint torques were analyzed by principal-component analysis to quantify the contributions of individual joints in kinematic and dynamic synergies. At the level of movement kinematics, we found subject-specific angular contributions. However, the adaptation to large aperture, achieved by an increase of the relative contribution of the proximal joints, was subject-invariant. At the level of movement dynamics, the adaptation of thumb-index finger movements to task constraints was similar among all subjects and required the linear scaling of joint torques, the synchronization of joint torques under high velocity conditions, and a flexible redistribution of joint torques between the proximal joint of the thumb and that of the index finger. This work represents one of the first attempts at calculating the joint torques during human precision-grip movements and indicates that the dynamic synergies seem to be remarkably simple compared with the synergies found for movement kinematics. PMID:15917316

Grinyagin, I V; Biryukova, E V; Maier, M A

2005-05-25

199

Kinematics of Reverse Time Imaging  

NASA Astrophysics Data System (ADS)

Prestack depth migration produces image gathers, which present the kinematic information implicit in seismic data in the form of redundant images of the subsurface. Most effective velocity estimation techniques rely on analysis of image gathers. This talk will describe a computation of image gathers using the full ("two-way") wave equation, known as reverse time imaging, in which the redundant parameter in the image is (subsurface) offset. Similar computations are routinely accomplished using depth extrapolation ("one-way" wave equation). Amongst other advantages, the two-way computation avoids the aperture limitation inherent in the one-way approach. Analysis also shows that two-way reverse time image gathers are free of kinematic artifacts (energetic events not corresponding to actual reflectors), at least near zero (subsurface) offset. Such kinematic artifacts often contaminate other forms of prestack imaging. This new construction of image gathers may provide a basis for reliable velocity analysis, hence imaging, in regions of severe refraction. such as gas chimneys and partial melts.

Symes, W. W.

2005-05-01

200

White dwarf kinematics versus mass  

NASA Astrophysics Data System (ADS)

We investigated the relationship between the kinematics and mass of young (<3 × 108 yr) white dwarfs using proper motions. Our sample is taken from the colour-selected catalogues of the Sloan Digital Sky Survey and the Palomar-Green Survey, both of which have spectroscopic temperature and gravity determinations. We find that the dispersion decreases with increasing white dwarf mass. This can be explained as a result of less scattering by objects in the Galactic disc during the shorter lifetime of their more massive progenitors. A direct result of this is that white dwarfs with high mass have a reduced scale height, and hence their local density is enhanced over their less massive counterparts. In addition, we have investigated whether the kinematics of the highest mass white dwarfs (>0.95 M?) are consistent with the expected relative contributions of single star evolution and mergers. We find that the kinematics are consistent with the majority of high-mass white dwarfs being formed through single star evolution.

Wegg, Christopher; Phinney, E. Sterl

2012-10-01

201

Kinematic models of cometary comae  

SciTech Connect

As a first step towards understanding the kinematics of cometary comae, an analysis was undertaken of the 18-cm OH lines in comets. This work builds on past OH excitation and kinematic studies to meld them into a complete and self-consistent model for a cometary coma. The kinematics were modeled via the vectorial formalism and the powerful Monte Carlo technique was used in an effort to reproduce the high sensitivity, high spectral resolution 18-cm OH line profiles of Comets Halley, Giacobini-Zinner, Hartley-Good, Thiele, and Wilson which were obtained at the 43 meter telescope of the National Radio Astronomy Observatory at Green Bank, West Virginia. For the first time a zeroth order A-doublet quenching correction was applied to the 18-cm data and the long standing UV/radio gas production rate disparity was accounted for. Gas expansion velocities and coma anisotropies were derived from observations covering a wide range of heliocentric distances and gas production rates. The inferred ratio of dayside gas emission to nightside gas emission for all comets in this study, except P/Giacobini-Zinner, is approx. two. This value is consistent with that derived from in situ observations of the neutral gas in the coma of Comet Halley and is independent of both gas productivity and heliocentric distance. For P/Giacobini-Zinner, anomalously high gas outflow anisotropies were inferred for which there is no clear explanation.

Tacconi-Garman, L.E.

1989-01-01

202

Jacobian-Free Newton-Krylov Discontinuous Galerkin (JFNK-DG) Method and Its Physics-Based Preconditioning for All-Speed Flows  

NASA Astrophysics Data System (ADS)

The Discontinuous Galerkin (DG) method for compressible fluid flows is incorporated into the Jacobian-Free Newton-Krylov (JFNK) framework. Advantages of combining the DG with the JFNK are two-fold: a) enabling robust and efficient high-order-accurate modeling of all-speed flows on unstructured grids, opening the possibility for high-fidelity simulation of nuclear-power-industry-relevant flows; and b) ability to tightly, robustly and high-order-accurately couple with other relevant physics (neutronics, thermal-structural response of solids, etc.). In the present study, we focus on the physics-based preconditioning (PBP) of the Krylov method (GMRES), used as the linear solver in our implicit higher-order-accurate Runge-Kutta (ESDIRK) time discretization scheme; exploiting the compactness of the spatial discretization of the DG family. In particular, we utilize the Implicit Continuous-fluid Eulerian (ICE) method and investigate its efficacy as the PBP within the JFNK-DG method. Using the eigenvalue analysis, it is found that the ICE collapses the complex components of the all eigenvalues of the Jacobian matrix (associated with pressure waves) onto the real axis, and thereby enabling at least an order of magnitude faster simulations in nearly-incompressible/weakly-compressible regimes with a significant storage saving.

Park, Hyeongkae; Nourgaliev, Robert; Knoll, Dana

2007-11-01

203

Analysis of pericentric inversions  

Microsoft Academic Search

In an attempt to address the origin of inversions in humans, we have analyzed the data pertaining to 249 pericentric inversions collated by Kaiser. A frequency distribution of the size of the inverted segments, expressed as a percentage of the human haploid autosomal chromosome length (HAL), showed periodicity when the data were binned at intervals of 0.5% HAL testing. This

S. N. Finkle; R. G. Gordon; P. J. McAlpine

1994-01-01

204

3D seismic inversion.  

National Technical Information Service (NTIS)

The research results from the 3D inversion have been made into products already available on the market. The new products are used both within the EU and in the rest of the world. The two partners in the 3D inversion project have launched two different pr...

K. Bolding Rasmussen J. Moerch Pedersen S. Gluck E. Juve

1997-01-01

205

Algebra Lab: Inverse Variation  

NSDL National Science Digital Library

This lesson from Algebra Lab demonstrates "how to write equations of quantities which vary inversely." The lesson includes an example of a graph of this type of equation, and several example problems. This supporting material would be best used following some in-class instruction explaining how to solve inverse variation equations.

2012-01-01

206

Nonlinear inversion of the P-wave P-wave reflection coefficient data  

SciTech Connect

Surface seismic data are used to estimate lithologic parameters at an interface. The four unknown independent parameters at an interface are the ratio of the P-wave velocities and the ratio of the densities of upper and lower media, and the P-wave/S-wave velocity ratios in the upper and lower media respectively. The forward problem is solved by a reparameterized form of the full Zoeppritz equation for PP reflections. The inversion model is fitted to the data using a two part inversion scheme. The near offset (near normal incidence) data is initially inverted using a linearized Zoeppritz normal incidence equation to obtain estimates of the P-wave ratio and density ratio. The estimates of these two parameters are then used as initial guesses in a nonlinear full Zoeppritz inversion by a Levenberg Marquardt procedure. Partial derivatives of the reparameterized Zoeppritz equation for the Jacobian matrix are calculated analytically at each iteration. All parameters are successfully estimated from synthetic data. Poisson`s ratio of the upper and lower media can be calculated from inversion estimates of P-wave/S-wave velocity ratio. Lithologic parameters are estimated for several CDP gathers from a 3D survey of the Rabbit Hills Field in North Central Montana. A sensitivity analysis for the different parameters is performed.

Pate, A.J. [Univ. of Montana, Butte, MT (United States)

1996-06-01

207

Joint Inversion of 3D Cross-well EM and DC Resistivity Data  

NASA Astrophysics Data System (ADS)

The imaging of hydrocarbon contaminants in the subsurface can best be detected with cross-well measurements, but the resolution of a cross-well EM or DC survey by itself is limited. We present a joint inversion algorithm for cross-well time domain EM and DC resistivity data that shows a frequency-dependent response, with the goal of improving resolution in the inverse model. The subsurface is discretized into hexahedral cells using a finite element method, and each cell is assigned a complex resistivity based on a standard Cole-Cole model. The electric field is modeled at the nodes of each of these cells based on a scattered-field approximation for the TDEM data, while in-phase and out-of-phase potentials are modeled for the DC resistivity data. The Jacobian matrix is determined through use of a reciprocity technique, and Dirichlet boundary conditions are assumed. Inversion is carried out using a non-linear conjugate gradient minimization method, with appropriate weighting allowing measurements from all time gates to be simultaneously inverted along with the DC data. The joint inversion can either solve for a single complex conductivity model, or for two models with equality or cross-gradient constraints. Results show improved resolution of complex targets compared to cross-well DC or EM surveys alone.

MacLennan, K.; Revil, A.; Karaoulis, M.

2011-12-01

208

Desktop 3-axis parallel kinematic milling machine  

Microsoft Academic Search

Parallel kinematic machines (PKM) are still a research-and-development topic in many laboratories although many of them, unfortunately,\\u000a have no PKM at all. Therefore, the use of a desktop educational 3-axis parallel kinematic milling machine is suggested as\\u000a a help in the process of acquiring basic experiences in the field of PKM. The developed desktop educational 3-axis parallel\\u000a kinematic milling machine

Milos Glavonjic; Dragan Milutinovic; Sasa Zivanovic; Zoran Dimic; Vladimir Kvrgic

2010-01-01

209

Kinematics analysis of six-bar parallel mechanism and its applications in synchrotron radiation beamline  

NASA Astrophysics Data System (ADS)

Six-bar parallel mechanism is now widely applied in synchrotron radiation beamline, while the six-dimensional adjustment is difficult and inefficient for lack of theoretical direction. This paper introduces a special six-bar parallel mechanism. By means of coordinate transformations, the inverse kinematics of six-bar parallel mechanism is studied, and the precise equations for six bars' lengths are obtained. Based on the inverse kinematics, forward kinematics of six-bar parallel mechanism is obtained with trust region method working for nonlinear optimization. The corresponding MATLAB program is also designed. The results show that trust region method is an effective way to solve forward kinematics, and the program is stable, reliable and rapid. This method has small errors with linear precision of 10-12 mm and rotational precision of 10-15 deg. Using differential snail adjustment, monochromator chamber's attitude can reach a linear resolution of 5 ?m and a rotational resolution of 3?, which entirely satisfies the practical requirements.

Lu, Qipeng; Li, Yongjun; Peng, Zhongqi

2012-05-01

210

Basic concepts of kinematic-wave models  

USGS Publications Warehouse

The kinematic-wave model is one of a number of approximations of the dynamic-wave model. The dynamic-wave model describes one-dimensional shallow-water waves (unsteady, gradually varied, open-channel flow). The report provides a basic reference on the theory and application of kinematic-wave models and describes the limitations of the model in relation to the other approximations of the dynamic-wave model. In the kinematic-wave approximation, a number of the terms in the equation of motion are assumed to be insignificant. The equation of motion is replaced by an equation describing uniform flow. Thus, the kinematic-wave model is described by the continuity equation and a uniform flow equation such as the well-known Chezy or Manning formulas. Kinematic-wave models are applicable to overland flow where lateral inflow is continuously added and is a large part of the total flow. For channel-routing applications, the kinematic-wave model always predicts a steeper wave with less dispersion and attenuation than actually occurs. The effect of the accumulation of errors in the kinematic-wave model shows that the approximations made in the development of the kinematic-wave equations are not generally justified for most channel-routing applications. Modified flow-routing models can be used which help to stop the accumulation of error that occurs when the kinematic-wave model is applied. (USGS)

Miller, J. E.

1984-01-01

211

Physics Suite Thinking Problems: Kinematics  

NSDL National Science Digital Library

This is a collection of introductory physics problems on topics in kinematics. The questions are designed for active learning classrooms and are built around research on student acquisition of knowledge. The problems vary in format and include context-based reasoning, multiple choice, estimation, and essay questions. The topics include velocity and acceleration, graphs, and different representations of motion. This item is part of a larger collection of problems, in-class questions, and interactive resources developed by the University of Maryland Physics Education Research Group.

Redish, Edward F.

2008-07-18

212

Impact of railroad ballast type on frontal plane ankle kinematics during walking  

Microsoft Academic Search

Five healthy male subjects walked on a control surface (level concrete), and two sloped rock surfaces (walking ballast—rock about 1.9cm across; main line ballast—rock about 3.8cm across) while their rearfoot motion (defined throughout as ankle inversion\\/eversion as seen from the frontal plane) was measured to determine if the different walking surfaces caused different ankle kinematics. The ballast was placed in

Robert O. Andres; Kenneth G. Holt; Masayoshi Kubo

2005-01-01

213

Experimental laboratory apparatus to analyze kinematics and 3D kinetics in rowing  

Microsoft Academic Search

In order to quantify internal forces and articular moments, by the inverse dynamics method, specially at lumbar level, an\\u000a experimental laboratory apparatus to analyze kinematics and 3D kinetics of rowers was developed. It comprised a 3D motion\\u000a analysis system, a Type C Concept II ergometer, three force-plates, six axes and two miniature mono-dimensional force transducers.\\u000a The apparatus was designed for

P. Pudlo; A. Pinti; F. X. Lepoutre

2005-01-01

214

Plasma inverse transition acceleration  

SciTech Connect

It can be proved fundamentally from the reciprocity theorem with which the electromagnetism is endowed that corresponding to each spontaneous process of radiation by a charged particle there is an inverse process which defines a unique acceleration mechanism, from Cherenkov radiation to inverse Cherenkov acceleration (ICA) [1], from Smith-Purcell radiation to inverse Smith-Purcell acceleration (ISPA) [2], and from undulator radiation to inverse undulator acceleration (IUA) [3]. There is no exception. Yet, for nearly 30 years after each of the aforementioned inverse processes has been clarified for laser acceleration, inverse transition acceleration (ITA), despite speculation [4], has remained the least understood, and above all, no practical implementation of ITA has been found, until now. Unlike all its counterparts in which phase synchronism is established one way or the other such that a particle can continuously gain energy from an acceleration wave, the ITA to be discussed here, termed plasma inverse transition acceleration (PITA), operates under fundamentally different principle. As a result, the discovery of PITA has been delayed for decades, waiting for a conceptual breakthrough in accelerator physics: the principle of alternating gradient acceleration [5, 6, 7, 8, 9, 10]. In fact, PITA was invented [7, 8] as one of several realizations of the new principle.

Xie, Ming

2001-06-18

215

Perspectives on geoacoustic inversion  

NASA Astrophysics Data System (ADS)

Over the past several decades, there has been a significant amount of research effort in ocean acoustics to develop methods for inverting parameters of geoacoustic models from measurements of the acoustic field in the ocean. This paper reviews the stages in the development of geoacoustic inversion as a statistical inference process to estimate geoacoustic model parameter values and their associated uncertainties. Limitations of model-based inversion methods such as matched field inversion are discussed. The paper concludes by discussing some new approaches that address limitations caused by uncertain ocean waveguide environments.

Chapman, N. Ross; Knobles, David P.

2012-11-01

216

Kinematic, workspace and singularity analysis of a new parallel robot used in minimally invasive surgery  

NASA Astrophysics Data System (ADS)

In the last ten years, due to development in robotic assisted surgery, the minimally invasive surgery has greatly changed. Until now, the vast majority of robots used in surgery, have serial structures. Due to the orientation parallel module, the structure is able to reduce the pressure exerted on the entrance point in the patient's abdominal wall. The parallel robot can also handle both a laparoscope as well an active instrument for different surgical procedures. The advantage of this parallel structure is that the geometric model has been obtained through an analytical approach. The kinematic modelling of a new parallel architecture, the inverse and direct geometric model and the inverse and direct kinematic models for velocities and accelerations are being determined. The paper will demonstrate that with this parallel structure, one can obtain the necessary workspace required for a minimally invasive operation. The robot workspace was generated using the inverse geometric model. An indepth study of different types of singularity is performed, allowing the development of safe control algorithms of the experimental model. Some kinematic simulation results and the experimental model of the robot are presented in the paper.

Stoica, Alin; Pisla, Doina; Andras, Szilaghyi; Gherman, Bogdan; Gyurka, Bela-Zoltan; Plitea, Nicolae

2013-03-01

217

Ballistic representation for kinematic access  

NASA Astrophysics Data System (ADS)

This work uses simple two-body orbital dynamics to initially determine the kinematic access for a ballistic vehicle. Primarily this analysis was developed to assess when a rocket body might conjunct with an orbiting satellite platform. A family of access opportunities can be represented as a volume for a specific rocket relative to its launch platform. Alternately, the opportunities can be represented as a geographical footprint relative to aircraft or satellite position that encompasses all possible launcher locations for a specific rocket. A thrusting rocket is treated as a ballistic vehicle that receives all its energy at launch and follows a coasting trajectory. To do so, the rocket's burnout energy is used to find its equivalent initial velocity for a given launcher's altitude. Three kinematic access solutions are then found that account for spherical Earth rotation. One solution finds the maximum range for an ascent-only trajectory while another solution accommodates a descending trajectory. In addition, the ascent engagement for the descending trajectory is used to depict a rapid access scenario. These preliminary solutions are formulated to address ground-, sea-, or air-launched vehicles.

Alfano, Salvatore

2011-01-01

218

The Inverse Laplace Transform  

NSDL National Science Digital Library

Created by Lang Moore for the Connected Curriculum Project, the purpose of this module is to illustrate the use of the residue theorem in calculating inverse laplace transforms. This is one of many learning modules hosted by Duke University.

Moore, Lang

2010-06-14

219

Inverses and Elementary Matrices  

NSDL National Science Digital Library

The purpose of this module is to explore the properties of inverse matrices. Our principal tool for this exploration is the expression of elementary row operations as left multiplications by elementary matrices.

Smith, David

2002-12-05

220

Interactive inversion in geosciences  

Microsoft Academic Search

Inversion algorithms numerically evaluate the mis- match between model and data to guide the search for minima in parameter spaces. In an alternative approach, the numerical evaluation of data misfit can be replaced by subjectively judging the solution's quality. This widens the class of problems that can be treated within the framework of formal inverse theory—in particular, var- ious geophysical\\/geological\\/geodynamic

F. Boschetti; L. Moresi

2001-01-01

221

Achieving Finite Element Mesh Quality via Optimization of the Jacobian Matrix Norm and Associated Quantities, Part 1 - A Framework for Surface Mesh Optimization  

SciTech Connect

Structured mesh quality optimization methods are extended to optimization of unstructured triangular, quadrilateral, and mixed finite element meshes. N"ew interpretations of well-known nodally-bssed objective functions are made possible using matrices and matrix norms. The matrix perspective also suggests several new objective functions. Particularly significant is the interpretation of the Oddy metric and the Smoothness objective functions in terms of the condition number of the metric tensor and Jacobian matrix, respectively. Objective functions are grouped according to dimensionality to form weighted combinations. A simple unconstrained local optimum is computed using a modiiied N-ewton iteration. The optimization approach was implemented in the CUBIT mesh generation code and tested on several problems. Results were compared against several standard element-based quaIity measures to demonstrate that good mesh quality can be achieved with nodally-based objective functions.

Knupp, P.M.

1999-01-18

222

On the Dispersion of Linear Kinematic Waves  

Microsoft Academic Search

The theory of kinematic waves, initiated by Lighthill & Whitham, is taken up for the case when the concentration k and flow q are related by a series of linear equations. If the initial disturbance is hump-like it is shown that the resulting kinematic wave can be usefully described by the growth of its mean and variance, the former moving

R. Aris

1958-01-01

223

Hamstring Muscle Kinematics during Treadmill Sprinting  

Microsoft Academic Search

THELEN, D. G., E. S. CHUMANOV, D. M. HOERTH, T. M. BEST, S. C. SWANSON, L. LI, M. YOUNG, and B. C. HEIDERSCHEIT. Hamstring Muscle Kinematics during Treadmill Sprinting. Med. Sci. Sports Exerc., Vol. 37, No. 1, pp. 108-114, 2005. Introduction\\/Purpose: The objective of this study was to characterize hamstring muscle kinematics during sprinting, so as to provide scientific data

DARRYL G. THELEN; ELIZABETH S. CHUMANOV; DINA M. HOERTH; THOMAS M. BEST; STEPHEN C. SWANSON; LI LI; MICHAEL YOUNG; BRYAN C. HEIDERSCHEIT

2005-01-01

224

Kinematics of the free throw in basketball  

NASA Astrophysics Data System (ADS)

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.

Tan, A.; Miller, G.

1981-06-01

225

Kinematics of the free throw in basketball  

Microsoft Academic Search

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.

A. Tan; G. Miller

1981-01-01

226

Kinematic problem of rigid body orientation control  

Microsoft Academic Search

The problem of reducing a coordinate system linked with a rigid body to a reference coordinate system rotating with a specified (programmed) angular velocity is analyzed using a kinematic formulation. The mathematic model of motion includes kinematic equations of the angular motion of a rigid body in nonnormalized quaternions; used as the controls are projections of the absolute angular velocity

P. K. Plotnikov; A. N. Sergeev; Iu. N. Chelnokov

1991-01-01

227

Programming and control of kinematically redundant manipulators  

Microsoft Academic Search

Because kinematically redundant robot manipulators have extra degrees of freedom with which to move and orient end effectors in the workspace, they offer a number of advantages over nonredundant designs. In this paper we show how extra degrees of freedom may be used to mitigate the problem of kinematically singular configurations. Programming and control techniques for resolution of redundancy are

John Baillieul; John Hollerbach; Roger Brockett

1984-01-01

228

Precision Robot Calibration Using Kinematically Placed Inclinometers  

Microsoft Academic Search

Relative calibration methods locate each robot link in a predefined position, relative to the previous link in the kinematic structure. This requires highly accurate robot parts, an expensive proposition for high volume manipulators. Optimal methods require a measurement system to measure a set of robot poses and use mathematical models of the robot kinematics to determine the link angles. The

Alec P. Robertson; Patrick J. Willoughby; Alexander Slocum

229

Peripheral arterial disease affects kinematics during walking  

Microsoft Academic Search

Objective: Claudication is the most common manifestation of peripheral arterial disease (PAD) producing significant ambulatory compromise. The purpose of this study was to use advanced biomechanical analysis to characterize the kinematic ambulatory pattern of claudicating patients. We hypothesized that compared with control subjects, claudicat- ing patients have altered kinematic gait patterns that can be fully characterized utilizing advanced biomechanical analysis.

Rolando Celis; Iraklis I. Pipinos; Melissa M. Scott-Pandorf; Sara A. Myers; Jason M. Johanning

2008-01-01

230

Time-lapse three-dimensional inversion of complex conductivity data using an active time constrained (ATC) approach  

NASA Astrophysics Data System (ADS)

Induced polarization (more precisely the magnitude and phase of impedance of the subsurface) is measured using a network of electrodes located at the ground surface or in boreholes. This method yields important information related to the distribution of permeability and contaminants in the shallow subsurface. We propose a new time-lapse 3-D modelling and inversion algorithm to image the evolution of complex conductivity over time. We discretize the subsurface using hexahedron cells. Each cell is assigned a complex resistivity or conductivity value. Using the finite-element approach, we model the in-phase and out-of-phase (quadrature) electrical potentials on the 3-D grid, which are then transformed into apparent complex resistivity. Inhomogeneous Dirichlet boundary conditions are used at the boundary of the domain. The calculation of the Jacobian matrix is based on the principles of reciprocity. The goal of time-lapse inversion is to determine the change in the complex resistivity of each cell of the spatial grid as a function of time. Each model along the time axis is called a 'reference space model'. This approach can be simplified into an inverse problem looking for the optimum of several reference space models using the approximation that the material properties vary linearly in time between two subsequent reference models. Regularizations in both space domain and time domain reduce inversion artefacts and improve the stability of the inversion problem. In addition, the use of the time-lapse equations allows the simultaneous inversion of data obtained at different times in just one inversion step (4-D inversion). The advantages of this new inversion algorithm are demonstrated on synthetic time-lapse data resulting from the simulation of a salt tracer test in a heterogeneous random material described by an anisotropic semi-variogram.

Karaoulis, M.; Revil, A.; Werkema, D. D.; Minsley, B. J.; Woodruff, W. F.; Kemna, A.

2011-10-01

231

Kinematic model of southern California  

SciTech Connect

A kinematic model for southern California, based on late-Quaternary slip rates and orientations of major faults in the region, is proposed. Internally consistent motions are determined assuming that these faults bound rigid blocks. Relative to North America, most of California west of the San Andreas fault is moving parallel to the San Andreas fault through the Transverse Ranges and not parallel to the motion of the Pacific plate. The velocities of the blocks are calculated along several paths in southern California that begin in the Mojave Desert and end off the California coast. A path that crosses the western Transverse Ranges accumulates the accepted relative North America-Pacific plate velocity, whereas paths to the north and south result in a significant missing component of motion, implying the existence of a zone of active deformation in southern California. 70 references.

Weldon, R.; Humphreys, E.

1986-02-01

232

Relating tolerances and kinematic behavior  

NASA Astrophysics Data System (ADS)

Designers usually complete the design with nominal dimensions and allocate tolerances only at the drawing stage. This practice can cause the following problems: (1) unnecessarily tight tolerances that require expensive manufacturing processes; (2) parts whose proper functioning is contingent on excessively tight tolerances; and (3) situations where slight wear on a part can seriously modify the behavior of the device. There is a need for computer-based techniques which allow designers to investigate the effect of manufacturing tolerances on the function their design performs. This paper presents a means for capturing the kinematic behavior of a device and relating it to the tolerances on its components. Behavior is represented using a configuration space representation, which we argue will be a useful tool for designers.

Bourne, D. A.; Navinchandra, D.; Ramaswamy, R.

1989-04-01

233

Pant-tilt Platform Design Based on Parallel Kinematics  

NASA Astrophysics Data System (ADS)

A new long distance measurement system design, based on parallel kinematics, is presented in this paper. This system has two degrees of freedom for positioning and orientating two high precision cameras. In this document is presented the system design. Several configurations have been analyzed and the components needed such as actuators, linear captators (to measure the displacement), spherical ball-and-socket joints and universal joints, have been selected. The developed model allows us to obtain the kinematic joint variables, depending on geometric parameters, by means of the resolution of opened chains for each leg. The direct model allows us to obtain the platform position and orientation for a determined displacement values. Once the matrix transformation (which describes the coordinates of the platform reference system respect to the base reference system) is obtained, the actuators elongation can be found out through the inverse model with numeric or geometric methods. The design optimization, by means of the analysis of anchorage points and the study of singularities (analysis of the limited platform positions, depending on maximum strut lengths and maximum angle that joints can turn), allows us to optimize the workspace of the platform.

Majarena, A. C.; Santolaria, J.; Aguilar, J. J.; Pastor, J.; Cajal, Cajal

2009-11-01

234

Kinematic determinants of human locomotion.  

PubMed Central

1. The aim of this study was to find kinematic patterns that are invariant across the normal range of locomotion speeds. Subjects walked at different, freely chosen speeds ranging from 0.9 to 2.1 m s-1, while motion and ground reaction forces on the right side of the body were recorded in three-dimensional space. 2. The time course of the anatomical angles of flexion-extension at the hip and ankle was variable not only across subjects, but even from trial to trial in the same subject. By contrast, the time course of the changes in the angles of elevation of each limb segment (pelvis, thigh, shank and foot) relative to the vertical was stereotyped across subjects. 3. To compare the waveforms across speeds, data were scaled in time relative to gait cycle duration. The pattern of ground reaction forces was highly speed dependent. Several distinct families of curves could be recognized in the flexion-extension angles at the hip and ankle. Instead, the waveforms of global length and elevation of the limb, elevation angles of all limb segments and flexion-extension at the knee were invariant with speed. 4. When gait trajectories at all speeds are plotted in the position space defined by the elevation angles of the limb segments, they describe regular loops on a plane. The statistical characteristics of these angular covariations were quantified by means of principal component analysis. The first two principal components accounted together for > 99% of the total experimental variance, and were quantitatively comparable in all subjects. 5. This constraint of planar covariation of the elevation angles is closely reminiscent of that previously described for the control of posture. The existence of laws of intersegmental co-ordination, common to the control of posture and locomotion, presumably assures the maintenance of dynamic equilibrium during forward progression, and the anticipatory adaptation to potentially destabilizing factors by means of co-ordinated kinematic synergies of the whole body. Images Figure 1

Borghese, N A; Bianchi, L; Lacquaniti, F

1996-01-01

235

Kinematic Coupling Along the Mexican Subduction Zone From GPS Data  

NASA Astrophysics Data System (ADS)

Kinematic coupling (?) between the subducting Cocos and Rivera oceanic plates, and the continental North America plate is estimated as a ratio between the back slip on the fault plane and the convergence rate (NUVEL1A model). To obtain a distribution of the back slip ("negative" displacement at the plate interface) along the coast of Jalisco, Guerrero, Oaxaca and Chiapas we performed an inversion of the surface crustal deformation data from the permanent GPS network "SSN-Sismologia-UNAM" and campaign GPS measurements. The displacements for each cell of the plate interface model were calculated using closed form expressions developed by Okada (1992). The inversion based on a simulated annealing algorithm reveals a high coupling ratio, ? ~ 1, at the seismogenic zone of 40-50 km width in Guerrero and Oaxaca, just beneath the coast line. Downdip from this area, a transition or partially coupled zone, ? ~ 0.28, extends for a distance of about 200 km. For the Isthmus of Tehuantepec zone, at the southeastern Oaxaca, the inversion model shows a very low coupling ratio. In Chiapas, at the southern Mexico Pacific coast, the sparse distribution of GPS stations does not allow us to constrain a satisfactory model. Nevertheless, some preliminary results show a coupled area close to the trench. At the northwest, along the coast of Jalisco, the observed surface crustal deformation is mostly a result of subduction of the Rivera Plate beneath the North America Plate. For this area, the campaign GPS data were obtained from the UNAVCO database. Preliminary results show a highly coupled seismogenic zone. Strongly coupled areas that were determined from the inversion models are in good agreement with the seismogenic zones defined with the rupture areas of large Mexican subduction thrust earthquakes (M > 6.5) occurred last century.

Franco, S.; Kostoglodov, V.; Iglesias, A.; Singh, S.

2007-05-01

236

Water vapor and temperature inversions near the 0 deg C level over the tropical western Pacific. Master's thesis  

SciTech Connect

During the Intensive Observation Period (IOP), several periods of water vapor and temperature inversions near the 0 deg C level were observed. Satellite and radiosonde data from TOGA COARE are used to document the large-scale conditions and thermodynamic and kinematic structures present during three extended periods in which moisture and temperature inversions near the freezing level were very pronounced. Observations from each case are synthesized into schematics which represent typical structures of the inversion phenomena. Frequency distributions of the inversion phenomena along with climatological humidity and temperature profiles are calculated for the four-month IOP.

Hart, K.A.

1994-01-01

237

Generalized inverse seesaw mechanisms  

NASA Astrophysics Data System (ADS)

The seesaw mechanism can be generalized to a type-III variant and a quintuplet variant. We present two models that provide analogous generalizations of the inverse seesaw mechanism. The first model employs a real fermion triplet F˜(1,3,0) and requires no additional multiplets or parameters relative to the standard inverse seesaw. We argue that, from a bottom-up perspective, there appears to be no particular reason to preference the usual scenario over this variant. The second model employs a fermion quintuplet F˜(1,5,0) and requires an additional scalar S˜(1,4,1). We also show that minimal inverse seesaws with even larger fermionic representations are not expected to realize naturally small neutrino masses.

Law, Sandy S. C.; McDonald, Kristian L.

2013-06-01

238

Inverting Source Time Functions to determine the fault kinematic characteristics  

NASA Astrophysics Data System (ADS)

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 to move from a high- to low-wavelength description of kinematic parameters on the fault. The optimal model parameter set is chosen according to Akaike Information Criterion [1974]. We present results for some synthetic tests and an application to a seismic events occurred during the 2009 L'Aquila (Central Italy) seismic sequence. In particular, we analyzed a small aftershock occurred on 2009 April 9, at 04:43:09 (UTC) characterized by a seismic moment of 1.07e+15 Nm (Mw 4). We found: a slip distribution, with an average value of 0.8 cm, characterized by a main slip patch located NW of the hypocenter and a rupture velocity distribution (mean value of 2.3 km/s) with a strong acceleration in the same direction.

Toraldo Serra, E. M.; Orefice, A.; Emolo, A.; Zollo, A.

2012-04-01

239

Inverse of Banded Matrices.  

National Technical Information Service (NTIS)

The inverses of r-banded matrices, for r = 1, 2, 3 have been thoroughly investigated as one can see from the references we provide. Let Br,n (1 less than or equal to r less than or equal to n) be an n x n matrix of entries (ai sub j), -r less than or equa...

E. Kilic P. Stanica

2013-01-01

240

Condensor Operated Inverse Thermosiphons.  

National Technical Information Service (NTIS)

A form of inverse thermosiphon is described and procedures for its use in thermal hydraulic design are outlined. The use of these procedures in the design of devices containing water as the working fluid is emphasized and charts for use in estimating perf...

D. Chisholm I. D. R. Grant P. J. D. Duncan

1978-01-01

241

Condenser Operated Inverse Thermosiphons.  

National Technical Information Service (NTIS)

An inverse thermosiphon was constructed and its operation evaluated. The use of an evaporator with a capillary surface was examined. Equations were developed for the lift ratio as a function of circulation rate and also for lift ratio to dryness fraction....

D. Chisholm I. D. R. Grant P. J. Duncan

1978-01-01

242

Inversion of Ocean Data.  

National Technical Information Service (NTIS)

When we began our study of inverse procedures to determine ocean circulation, our intent was to build on past studies. It turned out, however, that much of the earlier work contained elements that were unclear so we were forced to begin again and to estab...

M. Fiadeiro G. Veronis

1986-01-01

243

Inverse filtering and deconvolution  

Microsoft Academic Search

This paper studies the so-called inverse filtering and deconvolution problem from different angles. To start with, both exact and almost deconvolution problems are formulated, and the necessary and sufficient conditions for their solvability are investigated. Exact and almost deconvolution problems seek filters that can estimate the unknown inputs of the given plant or system either exactly or almostly whatever may

Ali Saberi; Anton A. Stoorvogel; Peddapullaiah Sannuti

2001-01-01

244

Inversion of triton moments  

NASA Astrophysics Data System (ADS)

We use the formalism of hyperspherical harmonics to calculate several moments for the triton photoeffect, for a Volkov spin-independent potential. First, we improve the accuracy of Maleki's calculations of the moments ?2 and ?3 by including more terms in the hyperspherical expansion. We also calculate moments ?0 and ?1 for a Serber mixture. We find reasonable agreement between our moments found by sum rules and those found from the cross sections calculated by Fang et al. and Levinger-Fitzgibbon. We then develop a technique of inversion of a finite number of moments by making the assumption that the cross section can be written as a sum of several Laguerre polynomials multiplied by a decreasing exponential. We test our inversion technique successfully on several model potentials. We then modify it and apply it to the five moments (?-1 to ?3) for a force without exchange, and find fair agreement with Fang's values of the cross section. Finally, we apply the inversion technique to our three moments (?-1,?0,and ?1) for a Serber mixture, and find reasonable agreement with Gorbunov's measurements of the 3He photoeffect. NUCLEAR REACTIONS Triton photoeffects, hyperspherical harmonics, moments of photoeffect, inversion of moments.

Clare, R. B.; Levinger, J. S.

1981-02-01

245

Inverse giant magnetoresistance (invited)  

SciTech Connect

Inverse giant magnetoresistance (GMR) is obtained in multilayers alternating two ferromagnetic layers {ital F}{sub 1} and {ital F}{sub 2} with different asymmetry of spin scattering, {alpha}{sub 1}{approx_gt}1 and {alpha}{sub 2}{lt}1. This is clearly demonstrated in the simple spin-valve system with perpendicular magnetization Fe{sub 1{minus}{ital x}}V{sub {ital x}}/Au/Co. With respect to Fe, the FeV alloys with {ital x}=0.18 and 0.29 exhibit an inversion of the spin scattering coefficients ({alpha}{sub Fe}{approx_gt}1, {alpha}{sub FeV}{lt}1) due to the change of the densities of states at the Fermi level. The inverse MR of FeV/Au/Co is studied as a function of FeV layer thickness and temperature and compared to calculations based on the Camley{endash}Barnas model. The data show that the inverse GMR is due to the bulk scattering within the FeV layer, which coexists with a substantial interface scattering favoring normal GMR. {copyright} {ital 1996 American Institute of Physics.}

Renard, J.; Bruno, P.; Megy, R.; Bartenlian, B.; Beauvillain, P.; Chappert, C.; Dupas, C.; Kolb, E.; Mulloy, M.; Prieur, J.; Veillet, P.; Velu, E. [Institut dElectronique Fondamentale, CNRS URA 022, Batiment 220, Universite Paris-Sud, 91405 Orsay Cedex (France)

1996-04-01

246

THE KINEMATICS OF SWIMMING IN ANURAN LARVAE  

Microsoft Academic Search

SUMMARY The kinematics of swimming in tadpoles from four species of anurans (Rana catesbeiana Shaw, Rana septentrionalis Baird, Rana clamitans Latreille and Bufo americanus Holbrook) was studied using computer- assisted analysis of high speed (^200 frames s\\

RICHARD J. WASSERSUG

1985-01-01

247

Star cluster kinematics with AAOmega  

NASA Astrophysics Data System (ADS)

The high-resolution setup of the AAOmega spectrograph on the Anglo-Australian Telescope makes it a beautiful radial velocity machine, with which one can measure velocities of up to 350-360 stars per exposure to +/-1--2 km/s in a 2-degree field of view. Here we present three case studies of star cluster kinematics, each based on data obtained on three nights in February 2008. The specific aims included: (i) cluster membership determination for NGC 2451A and B, two nearby open clusters in the same line-of-sight; (ii) a study of possible membership of the planetary nebula NGC 2438 in the open cluster M46; and (iii) the radial velocity dispersion of M4 and NGC 6144, a pair of two globular clusters near Antares. The results which came out of only three nights of AAT time illustrate very nicely the potential of the instrument and, for example, how quickly one can resolve decades of contradiction in less than two hours of net observing time.

Kiss, L. L.; Balog, Z.; Szabó, G. M.; Parker, Q. A.; Frew, D. J.

2008-08-01

248

Regge kinematics in soft collinear effective theory  

SciTech Connect

We discuss the kinematics of the particles that make up a Reggeon in field theory, using the terminology of the soft collinear effective theory (SCET). Reggeization sums a series of strongly ordered collinear emissions resulting in an overall Reggeon exchange that falls in the Glauber or Coulomb kinematic region. This is an extremely multiscale problem and appears to fall outside of the usual organizing scheme of SCET.

Donoghue, John F.; Wyler, Daniel [Department of Physics, University of Massachusetts, Amherst, Massachusetts 01003, USA, and Institut fuer Theoretische Physik, Universitaet Zuerich, 8057 Zuerich (Switzerland); Institut fuer Theoretische Physik, Universitaet Zuerich, 8057 Zuerich (Switzerland)

2010-06-01

249

Kinematics of tt¯ events at CDF  

Microsoft Academic Search

The kinematic properties of tt¯ events are studied in the W+multijet channel using data collected with the CDF detector during the 1992-1995 runs at the Fermilab Tevatron collider corresponding to an integrated luminosity of 109 pb-1. Distributions of a variety of kinematic variables chosen to be sensitive to different aspects of tt¯ production are compared with those expected from Monte

F. Abe; H. Akimoto; A. Akopian; M. G. Albrow; A. Amadon; S. R. Amendolia; D. Amidei; J. Antos; S. Aota; G. Apollinari; T. Arisawa; T. Asakawa; W. Ashmanskas; M. Atac; P. Azzi-Bacchetta; N. Bacchetta; S. Bagdasarov; M. W. Bailey; P. de Barbaro; A. Barbaro-Galtieri; V. E. Barnes; B. A. Barnett; M. Barone; G. Bauer; T. Baumann; F. Bedeschi; S. Behrends; S. Belforte; G. Bellettini; J. Bellinger; D. Benjamin; J. Bensinger; A. Beretvas; J. P. Berge; J. Berryhill; S. Bertolucci; S. Bettelli; B. Bevensee; A. Bhatti; K. Biery; C. Bigongiari; M. Binkley; D. Bisello; R. E. Blair; C. Blocker; K. Bloom; S. Blusk; A. Bodek; W. Bikhari; G. Bolla; Y. Bonushkin; D. Bortoletto; J. Boudreau; L. Breccia; C. Bromberg; N. Bruner; R. Brunetti; E. Buckley-Geer; H. S. Budd; K. Burkett; G. Busetto; A. Byon-Wagner; K. L. Byrum; M. Campbell; A. Caner; W. Carithers; D. Carlsmith; J. Cassada; A. Castro; D. Cauz; A. Cerri; P. S. Chang; H. Y. Chao; J. Chapman; M.-T. Cheng; M. Chertok; G. Chiarelli; C. N. Chiou; F. Chlebana; L. Christofek; R. Cropp; M. L. Chu; S. Cihangir; A. G. Clark; M. Cobal; E. Cocca; M. Contreras; J. Conway; J. Cooper; M. Cordelli; D. Costanzo; C. Couyoumtzelis; D. Cronin-Hennessy; R. Culbertson; D. Dagenhart; T. Daniels; F. Dejongh; S. dell'agnello; M. dell'orso; R. Demina; L. Demortier; M. Deninno; P. F. Derwent; T. Devlin; J. R. Dittmann; S. Donati; J. Done; T. Dorigo; N. Eddy; K. Einsweiler; J. E. Elias; R. Ely; E. Engels; W. Erdmann; D. Errede; S. Errede; Q. Fan; R. G. Feild; Z. Feng; C. Ferretti; I. Fiori; B. Flaugher; G. W. Foster; M. Franklin; J. Freeman; J. Friedman; H. Frisch; Y. Fukui; S. Gadomski; S. Galeotti; M. Gallinaro; O. Ganel; M. Garcia-Sciveres; A. F. Garfinkel; C. Gay; S. Geer; D. W. Gerdes; P. Giannetti; N. Giokaris; P. Giromini; G. Giusti; M. Gold; A. Gordon; A. T. Goshaw; Y. Gotra; K. Goulianos; H. Grassmann; C. Green; L. Groer; C. Grosso-Pilcher; G. Guillian; J. Guimaraes da Costa; R. S. Guo; C. Haber; E. Hafen; S. R. Hahn; T. Handa; R. Handler; W. Hao; F. Happacher; K. Hara; A. D. Hardman; R. M. Harris; F. Hartmann; J. Hausser; E. Hayashi; J. Heinrich; A. Heiss; B. Hinrichsen; K. D. Hoffman; C. Holck; R. Hollebeek; L. Holloway; Z. Huang; B. T. Huffman; R. Hughes; J. Huston; J. Huth; H. Ikeda; M. Incagli; J. Incandela; G. Introzzi; J. Iwai; Y. Iwata; E. James; H. Jensen; U. Joshi; E. Kajfasz; H. Kambara; T. Kamon; T. Kaneko; K. Karr; H. Kasha; Y. Kato; T. A. Keaffaber; K. Kelley; R. D. Kennedy; R. Kephart; D. Kestenbaum; D. Khazins; T. Kikuchi; B. J. Kim; H. S. Kim; S. H. Kim; Y. K. Kim; L. Kirsch; S. Klimenko; D. Knoblauch; P. Koehn; A. Köngeter; K. Kondo; J. Konigsberg; K. Kordas; A. Korytov; E. Kovacs; W. Kowald; J. Kroll; M. Kruse; S. E. Kuhlmann; E. Kuns; K. Kurino; T. Kuwabara; A. T. Laasanen; S. Lami; S. Lammel; J. I. Lamoureux; M. Lancaster; M. Lanzoni; G. Latino; T. Lecompte; S. Leone; J. D. Lewis; M. Lindgren; T. M. Liss; J. B. Liu; Y. C. Liu; N. Lockyer; O. Long; M. Loreti; D. Lucchesi; P. Lukens; S. Lusin; J. Lys; K. Maeshima; P. Maksimovic; M. Mangano; M. Mariotti; J. P. Marriner; G. Martignon; A. Martin; J. A. Matthews; P. Mazzanti; K. McFarland; P. McIntyre; P. Melese; M. Menguzzato; A. Menzione; E. Meschi; S. Metzler; C. Miao; T. Miao; G. Michail; R. Miller; H. Minato; S. Miscetti; M. Mishina; S. Miyashita; N. Moggi; E. Moore; Y. Morita; A. Mukherjee; T. Muller; A. Munar; P. Murat; S. Murgia; M. Musy; H. Nakada; T. Nakaya; I. Nakano; C. Nelson; D. Neuberger; C. Newman-Holmes; C.-Y. P. Ngan; L. Nodulman; A. Nomerotski; S. H. Oh; T. Ohmoto; T. Ohsugi; R. Oishi; M. Okabe; T. Okusawa; J. Olsen; C. Pagliarone; R. Paoletti; V. Papadimitriou; S. P. Pappas; N. Parashar; A. Parri; J. Patrick; G. Pauletta; M. Paulini; A. Perazzo; L. Pescara; M. D. Peters; T. J. Phillips; G. Piacentino; M. Pillai; K. T. Pitts; R. Plunkett; A. Pompos; L. Pondrom; J. Proudfoot; F. Ptohos; G. Punzi; K. Ragan; D. Reher; M. Reischl; A. Ribon; F. Rimondi; L. Ristori; W. J. Robertson; A. Robinson; T. Rodrigo; S. Rolli; L. Rosenson; R. Roser; T. Saab; W. K. Sakumoto; D. Saltzberg; A. Sansoni; L. Santi; H. Sato; P. Schlabach; E. E. Schmidt; M. P. Schmidt; A. Scott; A. Scribano; S. Segler; S. Seidel; Y. Seiya; F. Semeria; T. Shah; M. D. Shapiro; N. M. Shaw; P. F. Shepard; T. Shibayama; M. Shimojima; M. Shochet; J. Siegrist; A. Sill; P. Sinervo; P. Singh; K. Sliwa; C. Smith; F. D. Snider; J. Spalding; T. Speer; P. Sphicas; F. Spinella; M. Spiropulu; L. Spiegel; L. Stanco; J. Steele; A. Stefanini; R. Ströhmer; J. Strologas; F. Strumia; D. Stuart; K. Sumorok; J. Suzuki; T. Suzuki; T. Takahashi; T. Takano; R. Takashima; K. Takikawa; M. Tanaka; B. Tannenbaum; F. Tartarelli; W. Taylor; M. Tecchio; P. K. Teng; Y. Teramoto; K. Terashi; S. Tether; D. Theriot; T. L. Thomas; R. Thurman-Keup; M. Timko; P. Tipton; A. Titov; S. Tkaczyk; D. Toback; K. Tollefson; A. Tollestrup; H. Toyoda; W. Trischuk; J. F. de Troconiz

1999-01-01

250

Chemical Tagging of Solar Neighborhood Kinematic Streams  

NASA Astrophysics Data System (ADS)

Elemental abundance measurements for lanthanum, europium, and iron are presented for 504 stars in the solar neighborhood. The bulk of the data are planet search spectra taken with HIRES on the Keck I telescope at R=50,000, but a subset of 45 kinematically selected stars were observed on the Harlan J. Smith Telescope at McDonald Observatory at R=60,000 and S/N=100 at the 3988 angstrom lanthanum line and S/N=250 around 5240 angstrom near the iron lines. Statistical analyses of stellar kinematics in the solar neighborhood reveal much kinematic substructure in the disk, though it is not readily apparent whether this substructure is extragalactic or dynamical in origin. Much of the substructure can be quickly identified as well known moving groups of stars such as the Hercules, Sirius, and Hyades stellar streams. Additionally, the subset of kinematically selected stars observed at McDonald Observatory are members of a stellar stream putatively identified by Amina Helmi as part of a merger remnant. Taking advantage of a large data set and a homogeneous spectral analysis, a Kolmogorov-Smirnov hypothesis test is applied to investigate the possibility that these kinematic structures are chemically distinct from the Galactic Disk. In all cases, the kinematic streams have chemistries roughly consistent with the Galactic disk trends, although the statistical analyses suggest some subtle variations. The accretion hypothesis is not completely ruled out for Helmi's stream, but the chemical variations are interpreted primarily in terms of dynamical effects.

Stringer, Christopher Bayard

251

Direct inversion of stress, strain or strain rate including vorticity: A linear method of homogenous fault-slip data inversion independent of adopted hypothesis  

NASA Astrophysics Data System (ADS)

A direct linear fault-slip inversion method applicable to both the kinematic and the dynamic hypotheses is presented. If vorticity represents a parameter in the slip generating tensor, this results in an asymmetric tensor and increases the number of unknowns that must be determined by the inversion. By assuming that stress, strain or strain rate (depending on adopted hypothesis) are zero in the direction on the fault plane perpendicular to slip, it is shown that the moment method of fault-slip inversion can be expanded to a nine-dimensional parameter space to account for this asymmetry and calculate all seven parameters of the asymmetric slip generating tensor. While the symmetric part of the calculated tensor constrains the principal axes of stress, strain or strain rate in addition to their relative magnitude, the antisymmetric part of this tensor constrains the axis and magnitude of vorticity. The presented inversion method is robust because: (i) it is a direct linear calculation of the slip generating tensor; (ii) it is independent on the correct assessment of slip sense; (iii) it can evaluate the axis and magnitude of vorticity if present; and (iv) the same mathematical inversion method can be applied regardless whether the dynamic or kinematic hypotheses are adopted.

Hansen, John-Are

2013-06-01

252

Inverse Problems in Wave Scattering  

Microsoft Academic Search

The workshop treated inverse problems for partial differential equations, especially inverse scattering problems, and their applications in technology. While special attention was paid to sampling methods, decom- position methods, Newton methods and questions of unique determination were also investigated.

Martin Hanke-Bourgeois; Andreas Kirsch; William Rundell

2007-01-01

253

Direct and Inverse Variation  

NSDL National Science Digital Library

Lesson 1 of two lessons teaches students about direct variation by allowing them to explore a simulated oil spill using toilet paper tissues (to represent land) and drops of vegetable oil (to simulate a volume of oil). Lesson 2 teaches students about inverse variation by exploring the relationship between the heights of a fixed amount of water poured into cylindrical containers of different sizes as compared to the area of the containers' bases.

Media, Annenberg

2009-12-23

254

Design, kinematics and dynamics of a machine tool based on parallel kinematic structure  

Microsoft Academic Search

The objective of this research is to design, develop and analyse a novel machine tool based on the concept of parallel kinematic structure. This concept is widely recognised as having many significant advantages over conventional machine tools based on open kinematic structures, and accordingly is the subject of several major research efforts in many high-industrialised countries. ^ Tiara is the

Dan Centea

2005-01-01

255

Foot kinematics and loading of professional athletes in American football-specific tasks.  

PubMed

The purpose of this study was to describe stance foot and ankle kinematics and the associated ground reaction forces at the upper end of human performance in professional football players during commonly performed football-specific tasks. Nine participants were recruited from the spring training squad of a professional football team. In a motion analysis laboratory setting, participants performed three activities used at the NFL Scouting Combine to assess player speed and agility: the 3-cone drill, the shuttle run, and the standing high jump. The talocrural and first metatarsophalangial joint dorsiflexion, subtalar joint inversion, and the ground reaction forces were determined for the load bearing portions of each activity. We documented load-bearing foot and ankle kinematics of elite football players performing competition-simulating activities, and confirmed our hypothesis that the talocrural, subtalar, and metatarsophalangeal joint ranges of motion for the activities studied approached or exceeded reported physiological limits. PMID:22591791

Riley, Patrick O; Kent, Richard W; Dierks, Tracy A; Lievers, W Brent; Frimenko, Rebecca E; Crandall, Jeff R

2012-05-15

256

Priority Inversion and Its Prevention.  

National Technical Information Service (NTIS)

A priority inversion occurs when a low-priority task causes execution of a higher-priority task to be delayed. The possibility of priority inversion complicates the analysis of systems that use priority-based schedulers because priority inversions invalid...

F. B. Schneider K. Marzullo O. Babaoglu

1990-01-01

257

Inverse Problems. Activities for Undergraduates  

Microsoft Academic Search

This book is a valuable introduction to inverse problems. In particular, from the educational point of view, the author addresses the questions of what constitutes an inverse problem and how and why we should study them. Such an approach has been eagerly awaited for a long time. Professor Groetsch, of the University of Cincinnati, is a world-renowned specialist in inverse

Masahiro Yamamoto

2003-01-01

258

Effects of Initial Conditions on Inversions of Geodetic Data Using Rate-State Friction Models of Afterslip  

Microsoft Academic Search

Current afterslip modeling efforts in the geodetic community are moving away from a purely kinematic approach, in which slip is estimated using standard inversion methods, towards dynamic models that incorporate stress boundary conditions and fault rheology. Previous studies have modeled geodetic postseismic time series data as a response of a fault to instantaneous stress and velocity changes due to an

J. Fukuda; K. M. Johnson

2008-01-01

259

Chemical Tagging of Solar Neighborhood Kinematic Streams  

NASA Astrophysics Data System (ADS)

We present high resolution spectra measurements for Lanthanum, Europium, and Iron in 700 stars in the solar neighborhood. The bulk of our data are planet search spectra taken with HIRES on the Keck I telescope at R=50,000. A small subset of kinematically selected stars were observed on the Harlan J. Smith Telescope at McDonald Observatory at R=60,000 and S/N 100 at the 3988 Å Lanthanum line and S/N 250 around 5240 Å near the Iron lines. Statistical analyses of stellar kinematics in the solar neighborhood reveal much kinematic substructure in the disk, though it is not readily apparent whether this substructure is extragalactic or dynamical in origin. Much of the substructure can be quickly identified as well known moving groups of stars such as the Hercules, Sirius, and Hyades stellar streams. Additionally, our subset of kinematically selected stars observed at McDonald Observatory are members of a stellar stream putatively identified by Amina Helmi as part of a merger remnant. Taking advantage of a large data set and a homogenous spectral analysis, we apply a Kolmogorov-Smirnov hypothesis test to investigate the possibility that these kinematic structures are chemically distinct from the Galactic Disk.

Stringer, Christopher; Carney, B. W.

2011-01-01

260

A unified approach for local resolution of kinematic redundancy with inequality constraints and its application to nuclear power plant  

Microsoft Academic Search

In this paper, a closed-form formulation for inverse kinematics for redundant manipulators with inequality constraints has been proposed. This formulation has been derived by using the Kuhn-Tucker condition, the Lagrange multiplier method, and the active\\/working set method, so that its solution may satisfy the necessary and sufficient condition for optimization subject to equality and inequality constraints. From the formulation, computationally

K. C. Park; P. H. Chang; J. Kenneth Salisbury

1997-01-01

261

The kinematics and force analysis of a new leg mechanism for multi-legged wall-climbing robot  

Microsoft Academic Search

This paper presents a new kind of leg mechanism with which the wall-climbing robot can easily perform the ground-to-wall transition\\u000a by itself. To get its walking envelope and limit position, the forward\\/inverse kinematics and the statics of the mechanism\\u000a are solved. All of these lay the foundation for ground-to-wall transition gait programing, mechanism parameter selection and\\u000a optimization.

Yi Luo; Jinwu Qian; Yaozong Shen; Zhenbang Gong

1998-01-01

262

Adaptive Core Simulation Employing Discrete Inverse Theory - Part I: Theory  

SciTech Connect

Use of adaptive simulation is intended to improve the fidelity and robustness of important core attribute predictions such as core power distribution, thermal margins, and core reactivity. Adaptive simulation utilizes a selected set of past and current reactor measurements of reactor observables, i.e., in-core instrumentation readings, to adapt the simulation in a meaningful way. A meaningful adaption will result in high-fidelity and robust adapted core simulator models. To perform adaption, we propose an inverse theory approach in which the multitudes of input data to core simulators, i.e., reactor physics and thermal-hydraulic data, are to be adjusted to improve agreement with measured observables while keeping core simulator models unadapted. At first glance, devising such adaption for typical core simulators with millions of input and observables data would spawn not only several prohibitive challenges but also numerous disparaging concerns. The challenges include the computational burdens of the sensitivity-type calculations required to construct Jacobian operators for the core simulator models. Also, the computational burdens of the uncertainty-type calculations required to estimate the uncertainty information of core simulator input data present a demanding challenge. The concerns however are mainly related to the reliability of the adjusted input data. The methodologies of adaptive simulation are well established in the literature of data adjustment. We adopt the same general framework for data adjustment; however, we refrain from solving the fundamental adjustment equations in a conventional manner. We demonstrate the use of our so-called Efficient Subspace Methods (ESMs) to overcome the computational and storage burdens associated with the core adaption problem. We illustrate the successful use of ESM-based adaptive techniques for a typical boiling water reactor core simulator adaption problem.

Abdel-Khalik, Hany S.; Turinsky, Paul J. [North Carolina State University (United States)

2005-07-15

263

The kinematics of cosmic reheating  

NASA Astrophysics Data System (ADS)

We calculate the relaxation rate of a scalar field in a plasma of other scalars and fermions with gauge interactions using thermal quantum field theory. It yields the rate of cosmic reheating and thereby determines the temperature of the "hot big bang" in inflationary cosmology. The total rate originates from various processes, including decays and inverse decays as well as Landau damping by scatterings. It involves quantum statistical effects and off-shell transport. Its temperature dependence can be highly non-trivial, making it impossible to express the reheating temperature in terms of the model parameters in a simple way. We pay special attention to the temperature dependence of the phase space due to the modified dispersion relations in the plasma. We find that it can have a drastic effect on the efficiency of perturbative reheating, which depends on the way particles in the primordial plasma interact. For some interactions thermal masses can effectively close the phase space for the dominant dissipative processes and thereby impose an upper bound on the reheating temperature. In other cases they open up new channels of dissipation, hence increase the reheating temperature. At high temperatures we find that the universe can even be heated through couplings to fermions, which are often assumed to be negligible due to Pauli-blocking. These effects may also be relevant for baryogenesis, dark matter production, the fate of moduli and in scenarios of warm inflation.

Drewes, Marco; Kang, Jin U.

2013-10-01

264

Highly damped kinematic coupling for precision instruments  

DOEpatents

A highly damped kinematic coupling for precision instruments. The kinematic coupling provides support while causing essentially no influence to its nature shape, with such influences coming, for example, from manufacturing tolerances, temperature changes, or ground motion. The coupling uses three ball-cone constraints, each combined with a released flexural degree of freedom. This arrangement enables a gain of higher load capacity and stiffness, but can also significantly reduce the friction level in proportion to the ball radius divided by the distance between the ball and the hinge axis. The blade flexures reduces somewhat the stiffness of the coupling and provides an ideal location to apply constrained-layer damping which is accomplished by attaching a viscoelastic layer and a constraining layer on opposite sides of each of the blade flexures. The three identical ball-cone flexures provide a damped coupling mechanism to kinematically support the projection optics system of the extreme ultraviolet lithography (EUVL) system, or other load-sensitive apparatus.

Hale, Layton C. (Livermore, CA); Jensen, Steven A. (Livermore, CA)

2001-01-01

265

Adding kinematic constraints to purely differential dynamics  

NASA Astrophysics Data System (ADS)

The dynamics of unconstrained mechanical systems is governed by Ordinary Differential Equations (ODEs). When kinematic constraints need to be accounted for, Differential-Algebraic Equations (DAEs) arise. This work describes the introduction of kinematic constraints, expressed as algebraic relationships between the coordinates of unconstrained mechanical systems, ensuring compliance of the solution with up to the second-order derivative of holonomic constraint equations within the desired accuracy, without altering the ODE structure of the unconstrained problem. This represents a simple, little-intrusive, yet effective means to enforce kinematic constraints into existing formulations and implementations originally intended to address ODE problems, without the complexity of solving DAEs or resorting to implicit numerical integration schemes, and without altering the number and type of equations of the original unconstrained problem. The proposed formulation is compared to known approaches. Numerical applications of increasing complexity illustrate its distinguishing aspects.

Masarati, Pierangelo

2011-02-01

266

Geometry and Kinematics of the High Zagros Belt (Iran)  

NASA Astrophysics Data System (ADS)

The High Zagros Belt (HZB) is the most internal part of the wider Zagros Fold-Thrust Belt (ZFTB). It is an elevated domain (up to 4400 m) bounded to the south by the High Zagros Fault (HZF), which we define as the southernmost principal thrust-fault carrying out Lower Paleozoic strata over Mesozoic or Cenozoic rocks. To the north the HZB is bounded either by the Main Zagros Thrust (MZT), which corresponds to the fundamental limit (Neo-Tethys suture) with the internal Sanandaj-Sirjan Zone (pertaining to the Eurasian Plate) or by the front of the discontinuous "Crush Zone" (CZ) in which are exposed rocks coming from the distal margin of the former Neo-Tethys Ocean. Following our definition the HZB, exists in two disconnected prominent and elevated domains: the Central and Eastern High Zagros (CHZB& EHZB) respectively. The CHZB is a funnel shape region with a length of about 450 Km and variable width between 40 to 80 Km broadening from the NW to the SE. We will present a new tectonic map of this region and four new balanced cross-sections with associated kinematic models. From a geometric point of view, we show the existence of an important intermediate décollement level located within Ordovician-Silurian shale. This décollement, together with the well-known Hormuz basal décollement, allows the development of duplexes confined at depth in the core of the anticlines. For the kinematics, we confirm a two-steps model with a first thin-skinned phase leading to the development of large detachment folds developed over the Hormuz salt layer. At this stage the different intermediate décollement levels were activated. The second phase is thick-skinned and corresponds to the inversion of deep-seated basement faults and occurrence oflarge out-of-sequence thrusts,responsible for the exhumation of Lower Paleozoic rocks. The Eastern High Zagros Belt is a more restricted area composed by three giant anticlines, namely the Gakhum, Faraghan and Kue-e-Khush anticlines. Here also, we will present a new tectonic map and balanced-sections crossing the three anticlines. From a geometric point of view, the most striking structure is a major back-thrust floored by Ordovician shale in the Faraghan anticline. We will show that this back-thrust developed during an early thin-skinned phase of deformation and is subsequently cut out by basement faults. Finally, we will present an integrated kinematic model for the whole HZB.

Tavakoli, S.; Frizon de lamotte, D.; Ringenbach, J.-C.; Ballard, J.-F.

2012-04-01

267

Kinematic problem of rigid body orientation control  

NASA Astrophysics Data System (ADS)

The problem of reducing a coordinate system linked with a rigid body to a reference coordinate system rotating with a specified (programmed) angular velocity is analyzed using a kinematic formulation. The mathematic model of motion includes kinematic equations of the angular motion of a rigid body in nonnormalized quaternions; used as the controls are projections of the absolute angular velocity of body rotation to the coordinate axes. Two kinds of correction are proposed which represent quaternion analogs of the positional and integral corrections. Linear error equations for the orientation control system are obtained for the types of correction proposed here.

Plotnikov, P. K.; Sergeev, A. N.; Chelnokov, Iu. N.

1991-10-01

268

[Kinematics of metachronous walking. III. Invariants].  

PubMed

The concept of a kinematic space for a locomotor system is introduced and regime of locomotion is defined as a continued one-dimensional manifold of this space. The problem of describing of locomotion is set (settled) by kinematic invariants. It is shown that metachrony of such millipedes as Scolopendra and Julus can be considered as a special case of some "relativity principle", on the basis of which the expression of metachrony invariant has come out. The attempt is made to use this principle for the determination of step's invariants of each individual leg too. PMID:1203282

Smolianinov, V V; Karpovich, A L

269

Calibration of parallel kinematic devices using sequential determination of kinematic parameters  

SciTech Connect

In PKM Machines, the Cartesian position and orientation of the tool point carried on the platform is obtained from a kinematic model of the particular machine. Accurate positioning of these machines relies on the accurate knowledge of the parameters of the kinematic model unique to the particular machine. The parameters in the kinematic model include the spatial locations of the joint centers on the machine base and moving platform, the initial strut lengths, and the strut displacements. The strut displacements are readily obtained from sensors on the machine. However, the remaining kinematic parameters (joint center locations, and initial strut lengths) are difficult to determine when these machines are in their fully assembled state. The size and complexity of these machines generally makes it difficult and somewhat undesirable to determine the remaining kinematic parameters by direct inspection such as in a coordinate measuring machine. In order for PKMs to be useful for precision positioning applications, techniques must be developed to quickly calibrate the machine by determining the kinematic parameters without disassembly of the machine. A number of authors have reported techniques for calibration of PKMs (Soons, Masory, Zhuang et. al., Ropponen). In two other papers, the authors have reported on work recently completed by the University of Florida and Sandia National Laboratories on calibration of PKMs, which describes a new technique to sequentially determine the kinematic parameters of an assembled parallel kinematic device. The technique described is intended to be used with a spatial coordinate measuring device such as a portable articulated CMM measuring arm (Romer, Faro, etc.), a Laser Ball Bar (LBB), or a laser tracker (SMX< API, etc.). The material to be presented is as follows: (1) methods to identify the kinematic parameters of 6--6 variant Stewart platform manipulators including joint center locations relative to the workable and spindle nose, and initial strut lengths, (2) and example of the application of the method, and (3) results from the application of the technique.

JOKIEL JR.,BERNHARD; BIEG,LOTHAR F.; ZIEGERT,JOHN C.

2000-04-06

270

Delta rule-based neural networks for inverse kinematics: error gradient reconstruction replaces the teacher  

Microsoft Academic Search

Control tasks which feed back a scalar error signal (critic) to a controlling neural network form a more general class than those which provide a teacher that is ordinarily required by delta-rule-based networks like backpropagation or CMAC networks. The author introduces an interface that builds teacher vectors from critic values by reconstruction of the gradient of the critic function. Backpropagation

Heinz W. Werntges

1990-01-01

271

The Pindos Fold-and-thrust belt (Greece): inversion kinematics of a passive continental margin  

Microsoft Academic Search

Continuous exposure in the Pindos mountain chain (Greece) and the detailed stratigraphic measurements in the area enable us to construct eight balanced cross sections across the Pindos Fold-and-thrust belt (PFTB) and to approach quantitatively some parameters which controlled foreland evolution. The 160-km-wide passive continental margin of the Apulian continent in Greece was progressively shortened from east to west at rates

Konstantinos Skourlis; Theodor Doutsos

2003-01-01

272

Nuclear-matter distributions of halo nuclei from elastic proton scattering in inverse kinematics  

Microsoft Academic Search

:   Proton-nucleus elastic scattering at intermediate energies, a well-established method for probing nuclear-matter density distributions\\u000a of stable nuclei, was applied for the first time to exotic nuclei. This method is demonstrated to be an effective means for\\u000a obtaining accurate and detailed information on the size and radial shape of halo nuclei. Absolute differential cross-sections\\u000a for small-angle scattering were measured at

P. Egelhof; G. D. Alkhazov; M. N. Andronenko; A. Bauchet; A. V. Dobrovolsky; S. Fritz; G. E. Gavrilov; H. Geissel; C. Gross; A. V. Khanzadeev; G. A. Korolev; G. Kraus; A. A. Lobodenko; G. Münzenberg; M. Mutterer; S. R. Neumaier; T. Schäfer; C. Scheidenberger; D. M. Seliverstov; N. A. Timofeev; A. A. Vorobyov; V. I. Yatsoura

2002-01-01

273

Block model of western US kinematics from inversion of geodetic, fault slip, and earthquake data  

NASA Astrophysics Data System (ADS)

The active deformation of the southwestern US (30° to 41° N) is represented by a finite number of rotating, elastic spherical caps. Horizontal GPS velocities (1583), fault slip rates (94), and earthquake slip vectors (116) are inverted for block angular velocities, locking on block-bounding faults, and the rotation of individual GPS velocity fields relative to North America. GPS velocities are modeled as a combination of rigid block rotations and elastic strain rates resulting from interactions of adjacent blocks across bounding faults. The resulting Pacific - North America pole is indistinguishable from that of Beavan et al. (2001) and satisfies spreading in the Gulf of California and earthquake slip vectors in addition to GPS. The largest blocks, the Sierra Nevada - Great Valley and the eastern Basin and Range, show internal strain rates, after removing the elastic component, of only a few nanostrain/a, demonstrating long term approximately rigid behavior. Most fault slip data are satisfied except that the San Jacinto fault appears to be significantly faster than inferred from geology while the Coachella and San Bernardino segments of the San Andreas fault are slower, suggesting the San Andreas system is straightening out in Southern California. Vertical axis rotation rates for most blocks are clockwise and in magnitude more like the Pacific than North America. One exception is the eastern Basin and Range (242° E to 248° E) which rotates slowly anticlockwise about a pole offshore Baja.

McCaffrey, R.

2003-12-01

274

Center of mass based inverse kinematics algorithm for bipedal robot motion on inclined surfaces  

Microsoft Academic Search

Nowadays, humanoid researches are progressing widely in many applications. Some of the applications are walking in human environments such as on stairs and inclined floor. In order to solve this, there are researchers who implemented ankle torque control approach. However, by implementing this approach, it may saturate the ankle joints and if too much force is applied, it may damage

Fariz Ali; Barkan Ugurlu; Atsuo Kawamura

2010-01-01

275

Kinematically Redundant ARM Formulations for Coordinated Multiple ARM Implementations.  

National Technical Information Service (NTIS)

Although control laws for kinematically redundant robotic arms were presented as early as 1969, redundant arms have only recently become recognized as viable solutions to limitations inherent to kinematically sufficient arms. The advantages of run-time co...

R. W. Bailey L. J. Quiocho T. F. Cleghorn

1990-01-01

276

Constrained tri-sphere kinematic positioning system  

DOEpatents

A scalable and adaptable, six-degree-of-freedom, kinematic positioning system is described. The system can position objects supported on top of, or suspended from, jacks comprising constrained joints. The system is compatible with extreme low temperature or high vacuum environments. When constant adjustment is not required a removable motor unit is available.

Viola, Robert J (Jackson, WY)

2010-12-14

277

Kinematic Properties of Chromospheric Active Binary Stars  

NASA Astrophysics Data System (ADS)

The kinematic behaviour of 362 chromospherically active binary stars (CABs) in the solar neighbourhood were investigated. The Third CABs Catalog by Eker et al. (2008) was used as the main source. The spatial distribution and the components of the Galactic space velocities of the programme stars were determined. The effects of differential rotation and Local Standard of Rest (LSR) were corrected for all systems. Forty probable moving group (MG) members were determined by Eggen's criteria. The kinematic age of the young systems, which are probable members of MGs, was calculated as 0.79 (0.21) Gyr and the rest of 322 field stars were found to have a kinematic age of 4.38 (1.1) Gyr. Field CABs were separated into two sub-groups: dwarf systems, which were formed by main sequence (dwarf) stars, and evolved systems included at least one evolved (giant or sub-giant) component. The kinematic age of 134 dwarf systems was calculated as 4.69 (0.75) Gyr and 4.15 (1.29) Gyr for 188 evolved CABs.

Tüysüz, M.; Soydugan, F.; Bilir, S.; Demircan, O.

2012-04-01

278

Relativistic Kinematics for Motion Faster Than Light.  

National Technical Information Service (NTIS)

The use of conformal coordinates in relativistic kinematics is illustrated and a simple extension of the theory of motions faster than light is provided. An object traveling at a speed greater than light discloses its presence by appearing suddenly at a p...

R. T. Jones

1982-01-01

279

Stellar Archeology : Chemical Compositions and Kinematics  

NASA Astrophysics Data System (ADS)

The ?-CDM model of cosmology predicts a hierarchical formation mechanism of galaxies, with smaller units accreting to construct larger ones. The detection of merger events in external galaxies is well known, and the detection and analysis of merger remnants in the Milky Way is a key component in piecing together the history of our home galaxy. Statistical analyses of stellar kinematics in the solar neighborhood reveal much kinematic structure in the Galactic disk, but it is not readily apparent whether this structure is extragalactic or dynamical in origin. The most prominent structures are quickly identified as well known moving groups of stars such as the Hercules, Sirius, and Hyades stellar streams. Additionally, a subset of kinematically selected stars observed at McDonald Observatory are members of a stellar stream putatively identified by Amina Helmi as part of a merger remnant. A semi-automated, high resolution spectral analysis is applied to 504 F and G dwarf stars, and the results are amenable to Kolmogorov-Smirnov membership hypothesis testing. In all four cases, the kinematic streams have chemistries roughly consistent with the Galactic disk trends, although the statistical analyses suggest some subtle differences.

Stringer, Bayard; Carney, Bruce

2011-10-01

280

Error motion of a kinematic spindle  

Microsoft Academic Search

A prototype spindle for low-force, low-speed applications that is kinematically constrained in accordance with the principles of exact constraint was designed, fabricated, and tested. In the prototype spindle, the position and orientation of the shaft (rotor) are constrained at five contact points; four constraints are arranged radially around the rotor, and one constraint is located at the end of the

King-Fu Hii; R. Ryan Vallance; Robert D. Grejda; Eric R. Marsh

2004-01-01

281

Estimation methods for GPS kinematic data processing  

Microsoft Academic Search

The characteristics of three GPS kinematical data processing models, Least Square, Kalman filtering, and Semiparametric model are discussed and their advantages and disadvantages are compared. With observational data and pertinent data processing software, the applicable condition, context and effect of the three models are experimented. Results show that when the mobile platform is in uniform motion, the accuracy of the

Gang Chen; Xiong Pan

2009-01-01

282

Compton Effect with Non-Relativistic Kinematics  

ERIC Educational Resources Information Center

|In deducing the change of wavelength of x-rays scattered by atomic electrons, one normally makes use of relativistic kinematics for electrons. However, recoiling energies of the electrons are of the order of a few keV which is less than 0.2% of their rest energies. Hence the authors may ask whether relativistic formulae are really necessary. In…

Shivalingaswamy, T.; Kagali, B. A.

2011-01-01

283

Three-dimensional kinematics of hummingbird flight  

Microsoft Academic Search

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

Bret W. Tobalske; Douglas R. Warrick; Christopher J. Clark; Donald R. Powers; Tyson L. Hedrick; Gabriel A. Hyder; Andrew A. Biewener

2007-01-01

284

KINEMATIC ANALYSIS OF SOME BACKWARD ACROBATIC JUMPS  

Microsoft Academic Search

The aim of our investigation was to determine kinematic parameters of some acrobatic jumps backward, related to the difficulty categories in the current men's FIG Code of points. Ten male gymnasts performed ten different acrobatic jumps backward during the European championship in 1996 in Koebenhaven (Denmark). The analyzed elements were stretched salto backward, stretched salto backward with 1\\/1 turn, stretched

Ivan Cuk; Stanislav Ferkolj

285

The Kinematics of Contact and Grasp  

Microsoft Academic Search

The kinematics of contact describe the motion of a point of contact over the surfaces of two contacting objects in response to a relative motion of these objects. Using concepts from differential geometry, I derive a set of equations, called the contact equations, that embody this relationship. I employ the contact equations to design the following applications to be executed

David J. Montana

1988-01-01

286

Kinematic operator equations of rigid body rotation  

Microsoft Academic Search

Kinematic operator equations containing an absolute and a relative (local) derivative of the operator of rigid body rotation are analyzed. It is shown that general solutions to such equations determine the rules for the summation of finite rotations in the cases where the rotation axes are stationary in space and fixed within the body. Examples of the use of the

A. P. Panov

1986-01-01

287

Kinematical Test Theories for Special Relativity  

Microsoft Academic Search

A comparison of certain kinematical test theories for Special Relativity including the Robertson and Mansouri-Sext test theories is presented and the accuracy of the experimental results testing Special Relativity are expressed in terms of the parameters appearing in these test theories. The theoretical results are applied to the most precise experimental results obtained recently for the isotropy of light propagation

Claus Lämmerzahl; Claus Braxmaier; Hansjörg Dittus; Holger Müller; Achim Peters; Stephan Schiller

2002-01-01

288

Kinematics and the special theory of relativity  

Microsoft Academic Search

Consistent use of the principles of classical kinematics leads to interesting theorems, connecting the coefficients of linear\\u000a transformations between systems of inertia. Differential equations expressing such connections diminish the number of independent\\u000a postulates required for the establishment of the Lorentz group.

Z. Bay; J. A. White

1988-01-01

289

Kinematic Distance Assignments with H I Absorption  

NASA Astrophysics Data System (ADS)

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.

Jones, Courtney; Dickey, John M.

2012-07-01

290

Kinematic Measurements from YouTube Videos  

ERIC Educational Resources Information Center

|Video analysis of motion has been in use now for some time. However, some teachers may not have video equipment or may be looking for innovative ways to engage students with interesting applications at no cost. The recent advent of YouTube offers opportunities for students to measure kinematic properties of real-life events using their computers.…

Ruiz, Michael J.

2009-01-01

291

ANALYTIC MODELING OF THE MORETON WAVE KINEMATICS  

SciTech Connect

The issue whether Moreton waves are flare-ignited or coronal mass ejection (CME)-driven, or a combination of both, is still a matter of debate. We develop an analytical model describing the evolution of a large-amplitude coronal wave emitted by the expansion of a circular source surface in order to mimic the evolution of a Moreton wave. The model results are confronted with observations of a strong Moreton wave observed in association with the X3.8/3B flare/CME event from 2005 January 17. Using different input parameters for the expansion of the source region, either derived from the real CME observations (assuming that the upward moving CME drives the wave), or synthetically generated scenarios (expanding flare region, lateral expansion of the CME flanks), we calculate the kinematics of the associated Moreton wave signature. Those model input parameters are determined which fit the observed Moreton wave kinematics best. Using the measured kinematics of the upward moving CME as the model input, we are not able to reproduce the observed Moreton wave kinematics. The observations of the Moreton wave can be reproduced only by applying a strong and impulsive acceleration for the source region expansion acting in a piston mechanism scenario. Based on these results we propose that the expansion of the flaring region or the lateral expansion of the CME flanks is more likely the driver of the Moreton wave than the upward moving CME front.

Temmer, M.; Veronig, A. M. [IGAM/Kanzelhoehe Observatory, Institute of Physics, Universitaet Graz, Universitaetsplatz 5, A-8010 Graz (Austria); Vrsnak, B.; Zic, T. [Hvar Observatory, Faculty of Geodesy, University of Zagreb, Kaciceva 26, HR-10000 (Croatia)], E-mail: mat@igam.uni-graz.at

2009-09-10

292

Compound nucleus studies withy reverse kinematics  

SciTech Connect

Reverse kinematics reactions are used to demonstrate the compound nucleus origin of intermediate mass particles at low energies and the extension of the same mechanism at higher energies. No evidence has appeared in our energy range for liquid-vapor equilibrium or cold fragmentation mechanisms. 11 refs., 12 figs.

Moretto, L.G.

1985-06-01

293

Local POE model for robot kinematic calibration  

Microsoft Academic Search

A robot kinematic calibration method based on the local frame representation of the product-of-exponentials (Local POE) formula is introduced. In this method, the twist coordinates of the joint axes are expressed in their respective local (body) frames. The advantages of this new approach are threefolds: (1) revolute and prismatic joints can be uniformly expressed in the twist coordinates based on

I-Ming Chen; Guilin Yang; Chee Tat Tan; Song Huat Yeo

2001-01-01

294

Planetary Waves Kinematically Forced by Himalayan Orography  

Microsoft Academic Search

An analysis is made of the planetary-scale response of the atmosphere to the kinematic effects of orographic forcing by, in particular, the Tibetan Plateau-Himalayan Mountain complex. Theoretical scaling arguments are used to deduce a critical mountain height hc beyond which the component of flow around will dominate that over the orography. The hc is proportional to the meridional scale of

Kevin E. Trenberth; Shyh-Chin Chen

1988-01-01

295

KINEMATIC DISTANCE ASSIGNMENTS WITH H I ABSORPTION  

SciTech Connect

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.

Jones, Courtney; Dickey, John M. [School of Mathematics and Physics, Private Bag 37, University of Tasmania, Hobart 7000 (Australia)

2012-07-01

296

Kinematics of a PASCO Motorized Cart  

Microsoft Academic Search

A PASCO motorized cart is used to study the kinematic behavior of the cart when driven by a variety of waveforms produced by a PASCO 750 Interface and Power Amplifier II. The various shapes presented by the waveforms determine the time behavior of the driving voltage applied to the cart motor. Since students are typically exposed only to constant acceleration

Luke Trowbridge; Rachel Peters; Anne Franchek; Ken Taylor

2010-01-01

297

Inverse problem in hydrogeology  

NASA Astrophysics Data System (ADS)

The state of the groundwater inverse problem is synthesized. Emphasis is placed on aquifer characterization, where modelers have to deal with conceptual model uncertainty (notably spatial and temporal variability), scale dependence, many types of unknown parameters (transmissivity, recharge, boundary conditions, etc.), nonlinearity, and often low sensitivity of state variables (typically heads and concentrations) to aquifer properties. Because of these difficulties, calibration cannot be separated from the modeling process, as it is sometimes done in other fields. Instead, it should be viewed as one step in the process of understanding aquifer behavior. In fact, it is shown that actual parameter estimation methods do not differ from each other in the essence, though they may differ in the computational details. It is argued that there is ample room for improvement in groundwater inversion: development of user-friendly codes, accommodation of variability through geostatistics, incorporation of geological information and different types of data (temperature, occurrence and concentration of isotopes, age, etc.), proper accounting of uncertainty, etc. Despite this, even with existing codes, automatic calibration facilitates enormously the task of modeling. Therefore, it is contended that its use should become standard practice. L'état du problème inverse des eaux souterraines est synthétisé. L'accent est placé sur la caractérisation de l'aquifère, où les modélisateurs doivent jouer avec l'incertitude des modèles conceptuels (notamment la variabilité spatiale et temporelle), les facteurs d'échelle, plusieurs inconnues sur différents paramètres (transmissivité, recharge, conditions aux limites, etc.), la non linéarité, et souvent la sensibilité de plusieurs variables d'état (charges hydrauliques, concentrations) des propriétés de l'aquifère. A cause de ces difficultés, le calibrage ne peut êtreséparé du processus de modélisation, comme c'est le cas dans d'autres cas de figure. Par ailleurs, il peut être vu comme une des étapes dans le processus de détermination du comportement de l'aquifère. Il est montré que les méthodes d'évaluation des paramètres actuels ne diffèrent pas si ce n'est dans les détails des calculs informatiques. Il est montré qu'il existe une large panoplie de techniques d'inversion : codes de calcul utilisables par tout-un-chacun, accommodation de la variabilité via la géostatistique, incorporation d'informations géologiques et de différents types de données (température, occurrence, concentration en isotopes, âge, etc.), détermination de l'incertitude. Vu ces développements, la calibration automatique facilite énormément la modélisation. Par ailleurs, il est souhaitable que son utilisation devienne une pratique standardisée. Se sintetiza el estado del problema inverso en aguas subterráneas. El énfasis se ubica en la caracterización de acuíferos, donde los modeladores tienen que enfrentar la incertidumbre del modelo conceptual (principalmente variabilidad temporal y espacial), dependencia de escala, muchos tipos de parámetros desconocidos (transmisividad, recarga, condiciones limitantes, etc), no linealidad, y frecuentemente baja sensibilidad de variables de estado (típicamente presiones y concentraciones) a las propiedades del acuífero. Debido a estas dificultades, no puede separarse la calibración de los procesos de modelado, como frecuentemente se hace en otros campos. En su lugar, debe de visualizarse como un paso en el proceso de enten dimiento del comportamiento del acuífero. En realidad, se muestra que los métodos reales de estimación de parámetros no difieren uno del otro en lo esencial, aunque sí pueden diferir en los detalles computacionales. Se discute que existe amplio espacio para la mejora del problema inverso en aguas subterráneas: desarrollo de códigos amigables alusuario, acomodamiento de variabilidad a través de geoestadística, incorporación de información geológica y diferentes tipos de datos (temperatura, presencia y co

Carrera, Jesús; Alcolea, Andrés; Medina, Agustín; Hidalgo, Juan; Slooten, Luit J.

2005-03-01

298

Upper Limb Assessment in Tetraplegia: Clinical, Functional and Kinematic Correlations  

ERIC Educational Resources Information Center

|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…

Cacho, Enio Walker Azevedo; de Oliveira, Roberta; Ortolan, Rodrigo L.; Varoto, Renato; Cliquet, Alberto

2011-01-01

299

Tracking constant speed targets using a kinematic constraint  

Microsoft Academic Search

The tracking of constant speed, maneuvering targets is addressed through the use of a kinematic constraint. The trajectory of any constant speed target must satisfy the kinematic constraint A·V=0, where A and V are the target acceleration and velocity, respectively. The kinematic constraint is included in the filtering process is a pseudomeasurement. The formulation derived for the constraint equation provides

W. D. Blair; G. A. Waston; A. T. Alouani

1991-01-01

300

On the Kinematics of the Damped Lyman alpha Protogalaxies  

Microsoft Academic Search

We present the first results of an ongoing program to investigate the kinematic properties of high-redshift damped Ly alpha systems. Because damped Ly alpha systems are widely believed to be the progenitors of current massive galaxies, an analysis of their kinematics allows a direct test of galaxy formation scenarios. Specifically, the kinematic history of protogalactic gas is a sensitive discriminator

Jason X. Prochaska; Arthur M. Wolfe

1997-01-01

301

MINI EDUCATIONAL 3AXIS PARALLEL KINEMATIC MILLING MACHINE  

Microsoft Academic Search

Parallel kinematic machines (PKM) are still R&D topic in many laboratories although many of them unfortunately, have no PKM at all. Therefore the use of a low cost mini educational 3-axis parallel kinematic milling machine is suggested as a help in the proc- ess of acquiring basic experiences in the field of PKM. The developed mini educational 3-axis parallel kinematic

D. Milutinovic; M. Glavonjic; S. Zivanovic; Z. Dimic; V. Kvrgic

302

Inverse problem for Bremsstrahlung radiation  

SciTech Connect

For certain predominantly one-dimensional distribution functions, an analytic inversion has been found which yields the velocity distribution of superthermal electrons given their Bremsstrahlung radiation. 5 refs.

Voss, K.E.; Fisch, N.J.

1991-10-01

303

Kinematic Optimization in Birds, Bats and Ornithopters  

NASA Astrophysics Data System (ADS)

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.

Reichert, Todd

304

Kinematical Problem in Spin-Wave Theory  

NASA Astrophysics Data System (ADS)

A spin-1/2, nearest neighbor Heisenberg Hamiltonian acting on a periodic, d-dimensional lattice is considered. Multi-spin-wave solutions to the Schrödinger equation for a Heisenberg ferromagnet involve an unlimited superposition of spin-reversal operators at sites. This violates the physical restriction that no more than one excitation reside on any one site. This exclusion rule affects spin-wave interaction—the determination of these effects is called the kinematical problem. A general nonperturbative treatment that includes kinematical effects in spin-wave theory is developed along the following lines. Using the property of the Heisenberg Hamiltonian that it does not couple states obeying the single occupation condition at all sites with states that violate the single-occupancy condition at some sites, the unphysical multiply occupied states can be eliminated by a nonunitary transformation of the eigenvalue equation. An overcomplete Hamiltonian matrix is obtained that contains all the physical eigenvalues as a subset of its spectrum. Overcompleteness is shown to be a large part of the kinematical problem and several schemes to handle it are discussed. The remainder of the kinematical problem lies in the nonorthogonality of spin waves. It is shown that a new type of distribution, one that is neither Bose nor Fermi, correctly describes free spin-wave statistics at all temperatures. This formal but nonetheless complete solution to the overcompleteness aspect of the kinematical problem is then carried over, in toto, to the boson formulation of the spin Hamiltonian. Application to the calculation of the partition function and to thermal Green's functions is noted.

Stoller, Lincoln

1987-08-01

305

Foot Kinematics During a Bilateral Heel Rise Test in Participants With Stage II Posterior Tibial Tendon Dysfunction  

PubMed Central

STUDY DESIGN Experimental laboratory study using a cross-sectional design. OBJECTIVES To compare foot kinematics, using 3-dimensional tracking methods, during a bilateral heel rise between participants with posterior tibial tendon dysfunction (PTTD) and participants with a normal medial longitudinal arch (MLA). BACKGROUND The bilateral heel rise test is commonly used to assess patients with PTTD; however, information about foot kinematics during the test is lacking. METHODS Forty-five individuals volunteered to participate, including 30 patients diagnosed with unilateral stage II PTTD (mean ± SD age, 59.8 ± 11.1 years; body mass index, 29.9 ± 4.8 kg/m2) and 15 controls (mean ± SD age, 56.5 ± 7.7 years; body mass index, 30.6 ± 3.6 kg/m2). Foot kinematic data were collected during a bilateral heel rise task from the calcaneus (hindfoot), first metatarsal, and hallux, using an Optotrak motion analysis system and Motion Monitor software. A 2-way mixed-effects analysis of variance model, with normalized heel height as a covariate, was used to test for significant differences between the normal MLA and PTTD groups. RESULTS The patients in the PTTD group exhibited significantly greater ankle plantar flexion (mean difference between groups, 7.3°; 95% confidence interval [CI]: 5.1° to 9.5°), greater first metatarsal dorsiflexion (mean difference between groups, 9.0°; 95% CI: 3.7° to 14.4°), and less hallux dorsiflexion (mean difference, 6.7°; 95% CI: 1.7° to 11.8°) compared to controls. At peak heel rise, hindfoot inversion was similar (P = .130) between the PTTD and control groups. CONCLUSION Except for hindfoot eversion/inversion, the differences in foot kinematics in participants with stage II PTTD, when compared to the control group, mainly occur as an offset, not an alteration in shape, of the kinematic patterns.

HOUCK, JEFF; NEVILLE, CHRISTOPHER; TOME, JOSHUA; FLEMISTER, ADOLPH

2010-01-01

306

3D kinematics using dual quaternions: theory and applications in neuroscience  

PubMed Central

In behavioral neuroscience, many experiments are developed in 1 or 2 spatial dimensions, but when scientists tackle problems in 3-dimensions (3D), they often face problems or new challenges. Results obtained for lower dimensions are not always extendable in 3D. In motor planning of eye, gaze or arm movements, or sensorimotor transformation problems, the 3D kinematics of external (stimuli) or internal (body parts) must often be considered: how to describe the 3D position and orientation of these objects and link them together? We describe how dual quaternions provide a convenient way to describe the 3D kinematics for position only (point transformation) or for combined position and orientation (through line transformation), easily modeling rotations, translations or screw motions or combinations of these. We also derive expressions for the velocities of points and lines as well as the transformation velocities. Then, we apply these tools to a motor planning task for manual tracking and to the modeling of forward and inverse kinematics of a seven-dof three-link arm to show the interest of dual quaternions as a tool to build models for these kinds of applications.

Leclercq, Guillaume; Lefevre, Philippe; Blohm, Gunnar

2013-01-01

307

3D kinematics using dual quaternions: theory and applications in neuroscience.  

PubMed

In behavioral neuroscience, many experiments are developed in 1 or 2 spatial dimensions, but when scientists tackle problems in 3-dimensions (3D), they often face problems or new challenges. Results obtained for lower dimensions are not always extendable in 3D. In motor planning of eye, gaze or arm movements, or sensorimotor transformation problems, the 3D kinematics of external (stimuli) or internal (body parts) must often be considered: how to describe the 3D position and orientation of these objects and link them together? We describe how dual quaternions provide a convenient way to describe the 3D kinematics for position only (point transformation) or for combined position and orientation (through line transformation), easily modeling rotations, translations or screw motions or combinations of these. We also derive expressions for the velocities of points and lines as well as the transformation velocities. Then, we apply these tools to a motor planning task for manual tracking and to the modeling of forward and inverse kinematics of a seven-dof three-link arm to show the interest of dual quaternions as a tool to build models for these kinds of applications. PMID:23443667

Leclercq, Guillaume; Lefèvre, Philippe; Blohm, Gunnar

2013-02-20

308

MIMO communications and inverse scattering  

Microsoft Academic Search

We have developed an analogy between MIMO communications and inverse scattering to show that there is a close correspondence between the SNR behaviors of the communications channel capacity, effective degrees of freedom, and the quality of a reconstructed inverse image. These results have application to a MIMO configuration with coherently linked base stations, which can realize a capacity gain similar

K. F. Warnick

2009-01-01

309

Equations in Free Inverse Monoids  

Microsoft Academic Search

It is known that the problem of determining consistency of a finite system of equations in a free group or a free monoid is decidable, but the corresponding problem for systems of equations in a free inverse monoid of rank at least two is undecidable. Any solution to a system of equations in a free inverse monoid induces a solution

Timothy Deis; John C. Meakin; Géraud Sénizergues

2007-01-01

310

Model View of Inversion Evolution.  

National Technical Information Service (NTIS)

The evolution of low clouds and fog trapped under winter valley inversions can be a challenging forecast problem. Typically, model guidance struggles simply to forecast the inversion itself and has very little to add in terms of forecasting where low clou...

T. Barker

2008-01-01

311

A Note on Generalized Inverses.  

National Technical Information Service (NTIS)

It is evident from the variety of properties of the generalized inverse that it is a matrix form which has many powerful uses in the theoretical studies and in practical applications. Historical development of the generalized inverse is given. Basic defin...

H. J. Malik

1968-01-01

312

Trans-dimensional geoacoustic inversion.  

PubMed

This paper develops a general trans-dimensional Bayesian methodology for geoacoustic inversion. Trans-dimensional inverse problems are a generalization of fixed-dimensional inversion that includes the number and type of model parameters as unknowns in the problem. By extending the inversion state space to multiple subspaces of different dimensions, the posterior probability density quantifies the state of knowledge regarding inversion parameters, including effects due to limited knowledge about appropriate parametrization of the environment and error processes. The inversion is implemented here using a reversible-jump Markov chain Monte Carlo algorithm and the seabed is parametrized using a partition model. Unknown data errors are addressed by including a data-error model. Jumps between dimensions are implemented with a birth-death methodology that allows transitions between dimensions by adding or removing interfaces while maintaining detailed balance in the Markov chain. Trans-dimensional inversion results in an inherently parsimonious solution while partition modeling provides a naturally self-regularizing algorithm based on data information content, not on subjective regularization functions. Together, this results in environmental estimates that quantify appropriate seabed structure as supported by the data, allowing sharp discontinuities while approximating smooth transitions where needed. This approach applies generally to geoacoustic inversion and is illustrated here with seabed reflection-coefficient data. PMID:21218873

Dettmer, Jan; Dosso, Stan E; Holland, Charles W

2010-12-01

313

A kinematic method to probe cosmic acceleration  

NASA Astrophysics Data System (ADS)

We propose a method to map the cosmological evolution of the main kinematic parameters H, q and j from observational data. Unlike the traditional approach, the methodology here discussed provides constraints on the kinematic parameters not only at z=0 but also at any value of the redshift parameter. By choosing the scale factor as expansion variable in order to avoid the series convergence and truncation problems, we perform a Taylor expansion of the luminosity distance around an arbitrary a˜ and use current type Ia supernovae data to estimate the values of H, q and j for 0.41?a˜?1 (0?z?1.4). We show that the transition from a decelerated phase to an accelerating one occurs in the range 0.4?z?0.9 and that for z?0.5 the value of j=1 is ruled out in 2? confidence level.

Barboza, Edésio M.; Carvalho, F. C.

2012-08-01

314

The LAMOST Pilot Survey: Local Kinematics  

NASA Astrophysics Data System (ADS)

We explore disk kinematics using the Large Sky Area Area Mulit-Object Fiber Spectroscopic Telescope (LAMOST) pilot survey. Spectra for 484,185 stars with magnitudes 10 to 18 were released after being observed using the Guo Shou Jing Telescope in the pilot survey. Because the majority of the stars with sufficient signal-to-noise for velocity measurements are bright, we focus our study on the Milky Way disk. We show the local kinematics of the disk using these stars, which show gradients in the radial and rotational motion along with longitudinal asymmetries. Funding for this project has been provided by The NASA/NY Space Grant, NSF grant AST 10-09670, NSF grant AST 09-37523 and NSFC grants 10973015 and 11061120454.

DeLaunay, James; Newberg, H. J.; Carlin, J. L.; Gole, D.; Deng, L.; Liu, X.; Luo, A.; Zhang, H.

2013-01-01

315

Kinematics of swimming garter snakes (Thamnophis sirtalis).  

PubMed

We investigate the kinematics of swimming garter snakes (Thamnophis sirtalis) using a novel nonlinear regression-based digitization method to establish quantitative statistical support for non-constant wavelengths in the undulatory pattern exhibited by swimming snakes. We find that in swimming snakes, the growth of the amplitude of the propulsive wave head-to-tail is strongly correlated (p < 0.005) with the head-to-tail growth in the wavelength. We investigate correlations between kinematic parameters and steady swimming speed, and find a very strong positive correlation between swimming speed and undulation frequency. We furthermore find a statistically well-supported positive correlation between swimming speed and both the initial amplitude of the propulsive wave at the head and the degree of amplitude growth from head to tail. PMID:17950016

Munk, Yonatan

2007-09-14

316

Kinematic invariants during cyclical arm movements  

Microsoft Academic Search

It has been observed that the motion of the arm end-point (the hand, fingertip or the tip of a pen) is characterized by a\\u000a number of regularities (kinematic invariants). Trajectory is usually straight, and the velocity profile has a bell shape during\\u000a point-to-point movements. During drawing movements, a two-thirds power law predicts the dependence of the end-point velocity\\u000a on the

Natalia Dounskaia

2007-01-01

317

Saybolt universal viscosity converted to kinematic  

Microsoft Academic Search

This article describes a program for personal and handheld computers, written in Basic, which has been developed for the conversion of Saybolt universal viscosity in Saybolt Universal Seconds (SSU or SUS) to kinematic viscosity in centistokes (cSt), at any selected temperature. It was developed using the mathematical relationship presented in the American Society for Testing and Materials (ASTM) standard D2161-82.

C. Anaya; O. Bermudez

1987-01-01

318

Evaluation of Precise, Kinematic GPS Point Positioning  

Microsoft Academic Search

We present the results of precise static and kinematic point-positioning solutions obtained in post-processing, with a recursive Kalman filter and smoother estimator (i.e., a state space approach). The observations are dual- frequency GPS carrier phase and pseudo-range, treated as two distinct data types, each with its own measurement equations. The receiver data is single-differenced between satellites, to eliminate the receiver

Oscar L. Colombo; Andrew W. Sutter; Alan G. Evans

319

Kinematics in Special and General Relativity  

Microsoft Academic Search

This thesis investigates the problem of motion for extended bodies from the viewpoint of classical field theory, where the classical field is the body's energy-momentum or matter tensor.\\u000aIn Special Relativity a symmetric and divergence-free matter tensor combined with inertial frames is used to generate a kinematics for extended bodies; but I have shown that if the matter tensor also

Robert William Maclaren Woodside

1979-01-01

320

Kinematics in irregular galaxies: NGC 4449.  

NASA Astrophysics Data System (ADS)

A kinematical analysis of the irregular galaxy NGC 4449 is presented based on the Fabry-Perot interferometer PUMA observations. In NGC 4449 we analyse its global velocity field, HII regions population as well as the SNR population identified on radioastronomy studies. Our first results for NGC 4449 show that the optical velocity field, presents a decreasing gradient in velocity along the optical bar and an anticorrelation with respect to the velocity field of the HI halo.

Valdez, M.; Rosado, M.

1998-11-01

321

Kinematic bending moments in pile foundations  

Microsoft Academic Search

In this paper the kinematic seismic interaction of single piles embedded in soil deposits is evaluated by focusing the attention on the bending moments induced by the transient motion. The analysis is performed by modeling the pile like an Euler–Bernoulli beam embedded in a layered Winkler-type medium. The excitation motion is obtained by means of a one-D propagation analysis. A

F. Dezi; S. Carbonari; G. Leoni

2010-01-01

322

Kinetic and kinematic adaptation to anisotropic load  

Microsoft Academic Search

Different investigators have proposed that multi-joint arm movements are planned with respect to either the path of the hand\\u000a or the forces and torques acting about the moving joints. In this experiment, we examined the kinematic and kinetic response\\u000a of the motor system when a load was applied to the forearm, which reduced the natural anisotropy of the arm. We

Jonathan Shemmell; Daniel M. Corcos; Ziaul Hasan

2009-01-01

323

Fault-Zone Reactivation: Kinematics and Mechanisms  

NASA Astrophysics Data System (ADS)

The kinematics and mechanisms of fault-zone reactivation are reviewed. Reactivation is dependent upon fault-zone orientation and the existence of weak mylonites along these zones. The recognition of reactivation within mylonite zones, and the softening processes that first concentrate deformation into these and secondly provide a weak medium for reactivation are discussed. Attention is given to the Darling Mobile Zone, Western Australia and the Redbank Zone (see Obee & White, this symposium) as examples of reactivated zones.

White, S. H.; Bretan, P. G.; Rutter, E. H.

1986-04-01

324

The Montgomery Modular Inverse-Revisited  

Microsoft Academic Search

We modify an algorithm given by Kaliski to compute the Montgomery inverse of an integer modulo a prime number. We also give a new definition of the Montgomery inverse, and introduce efficient algorithms for computing the classical modular inverse, the Kaliski- Montgomery inverse, and the new Montgomery inverse. The proposed algorithms are suitable for software imple- mentations on general-purpose microprocessors.

Erkay Savas; Çetin Kaya Koç

2000-01-01

325

New Kinematical Constraints on Cosmic Acceleration  

SciTech Connect

We present and employ a new kinematical approach to ''dark energy'' studies. We construct models in terms of the dimensionless second and third derivatives of the scale factor a(t) with respect to cosmic time t, namely the present-day value of the deceleration parameter q{sub 0} and the cosmic jerk parameter, j(t). An elegant feature of this parameterization is that all {Lambda}CDM models have j(t)=1 (constant), which facilitates simple tests for departures from the {Lambda}CDM paradigm. Applying our model to redshift-independent distance measurements, from type Ia supernovae and X-ray cluster gas mass fraction measurements, we obtain clear statistical evidence for a late time transition from a decelerating to an accelerating phase. For a flat model with constant jerk, j(t)=j, we measure q{sub 0}=-0.81 {+-} 0.14 and j=2.16 +0.81 -0.75, results that are consistent with {Lambda}CDM at about the 1{sigma} confidence level. In comparison to dynamical analyses, the kinematical approach uses a different model set and employs a minimum of prior information, being independent of any particular gravity theory. The results obtained with this new approach therefore provide important additional information and we argue that both kinematical and dynamical techniques should be employed in future dark energy studies, where possible.

Rapetti, David; Allen, Steve W.; Amin, Mustafa A.; Blandford, Roger; /-KIPAC, Menlo Park

2007-05-25

326

Scapula kinematics differ by body mass index.  

PubMed

The biomechanical changes due to increased arm mass in individuals with high body mass index (BMI) may lead to altered scapular motions at the shoulder joint. Scapula kinematic alterations are often associated with shoulder pain and pathology, and if present in overweight or obese individuals could impact shoulder health. The purpose of this study was to examine if scapula biomechanics differ between groups separated by BMI. Three-dimensional scapula kinematic data during arm elevation were collected on 41 subjects, and then compared between higher BMI (BMI ? 27; n = 10) and lower BMI (BMI ? 23; n = 10) individuals, both with and without holding a 1.36 kg (3 lb) weight. Data were analyzed with a mixed-model ANOVA with Group and Elevation Angle the between- and within-subject factors, respectively. The higher BMI group had significantly greater scapula upward rotation than the lower BMI group at 120° for both the unweighted and weighted tasks. Individuals with higher BMI in this study had altered scapulothoracic movement, which may be a strategy to better manage increased arm mass. With increased scapula upward rotation also reported in groups with rotator cuff tears, this study supports the potential link between high BMI, kinematics, and rotator cuff pathology. PMID:22923369

Gupta, Miti; Dashottar, Amitabh; Borstad, John D

2012-08-22

327

Scapula kinematics differ by body mass index.  

PubMed

The biomechanical changes due to increased arm mass in individuals with high body mass index (BMI) may lead to altered scapular motions at the shoulder joint. Scapula kinematic alterations are often associated with shoulder pain and pathology, and if present in overweight or obese individuals could impact shoulder health. The purpose of this study was to examine if scapula biomechanics differ between groups separated by BMI. Three-dimensional scapula kinematic data during arm elevation were collected on 41 subjects, and then compared between higher BMI (BMI ? 27; n = 10) and lower BMI (BMI ? 23; n = 10) individuals, both with and without holding a 1.36 kg (3 lb) weight. Data were analyzed with a mixed-model ANOVA with Group and Elevation Angle the between- and within-subject factors, respectively. The higher BMI group had significantly greater scapula upward rotation than the lower BMI group at 120° for both the unweighted and weighted tasks. Individuals with higher BMI in this study had altered scapulothoracic movement, which may be a strategy to better manage increased arm mass. With increased scapula upward rotation also reported in groups with rotator cuff tears, this study supports the potential link between high BMI, kinematics, and rotator cuff pathology. PMID:24021983

Gupta, Miti; Dashottar, Amitabh; Borstad, John D

2013-08-01

328

Milky Way Kinematics from RAVE Data  

NASA Astrophysics Data System (ADS)

We present a method to derive kinematic parameters for the Galactic thick and thin disks of the Milky Way (MW) based on the Radial Velocity Experiment (RAVE Steinmetz et al. 2006). We introduce selection criteria in order to clean the observed radial velocities from the Galactic large scale effects and to take into account the partial sky coverage of RAVE. The data are disentangled from a mixture of thin and thick disk stars as explained in a forthcoming paper (Pasetto et al. 2012) on the basis of pure kinematics arguments and supplied with photometric distances and proper motions. We deduce the components of the Solar motion relative to the Local Standard of Rest (LSR) in the radial and vertical directions as well as the components of the velocity dispersion tensors for the two MW component on the basis of pure kinematics arguments. The selected sample is a limited subsample from the RAVE catalogue roughly extending 500 pc above and below the Galactic plane. This sample tracks the velocity dispersion trend in radial direction to 1 kpc within and 500pc outside the Solar radius in the Galactic reference system.

Pasetto, S.; Grebel, E. K.; RAVE Co.

2012-08-01

329

Computational tool for comparison of kinematic mechanisms and commonly used kinematic models  

SciTech Connect

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.

Hollerbach, K.; Hollister, A.M.; Van Vorhis, R.L.

1997-03-01

330

Inverse thermoremanent magnetization  

NASA Astrophysics Data System (ADS)

Inverse thermoremanent magnetization (ITRM) is reversed to the thermoremanent magnetization (TRM) process: ITRM results from warming from low temperature T in a magnetic field, while TRM results from field cooling from high T. The development of ITRM was studied in magnetites of grain sizes from submicron to 135 ?m, in pyrrhotites and in hematite crystals. All three minerals acquired ITRM after warming through their magnetic transitions (35 K for pyrrhotite, 120 and 130 K for magnetite, 250 K for hematite). However, when an impacting meteorite's cold interior warms to ambient T in the geomagnetic field, magnetite is the most likely candidate for acquiring ITRM. The magnetite ITRM blocking temperature distribution was determined from 12 neighboring partial ITRMs in nested field-on warming plus field-off cooling cycles (300-20 K). The largest partial ITRMs are produced in T intervals around magnetite's Verwey transition (TV = 110-120 K) and isotropic point (TK = 130 K). Both transitions involve large changes in crystalline anisotropy and renucleation of magnetic domains. ITRM is blocked when initially broad domain walls narrow and are pinned by dislocations. ITRM has contrasting properties to TRM, which is mainly due to blocked single-domain moments. ITRM is strongest for 3- to 20-?m grains, whereas TRM peaks for submicron magnetites. Only 10-20% of ITRM survives low-temperature demagnetization (LTD) at 77 K or AF demagnetization to 10-15 mT, compared to 30-90% for TRM. ITRM decreases quasi-linearly with T in thermal demagnetization. The median unblocking temperature TUB is ?300°C and 20-25% survives at 550°C. The low-TUB part of ITRM could mimic extraterrestrial NRM of low TUB, cited as evidence of negligible heating of meteorites in their transfer to Earth. The high-TUB ITRM would contaminate paleointensity determinations up to the highest T steps. The best cure for ITRM contamination is AF or LTD pretreatment.

Dunlop, David J.

2006-12-01

331

Givental Graphs and Inversion Symmetry  

NASA Astrophysics Data System (ADS)

Inversion symmetry is a very non-trivial discrete symmetry of Frobenius manifolds. It was obtained by Dubrovin from one of the elementary Schlesinger transformations of a special ODE associated to a Frobenius manifold. In this paper, we review the Givental group action on Frobenius manifolds in terms of Feynman graphs and obtain an interpretation of the inversion symmetry in terms of the action of the Givental group. We also consider the implication of this interpretation of the inversion symmetry for the Schlesinger transformations and for the Hamiltonians of the associated principle hierarchy.

Dunin-Barkowski, Petr; Shadrin, Sergey; Spitz, Loek

2013-05-01

332

Inverse melting and inverse freezing: A spin model  

NASA Astrophysics Data System (ADS)

Systems of highly degenerate ordered or frozen state may exhibit inverse melting (reversible crystallization upon heating) or inverse freezing (reversible glass transition upon heating). This phenomenon is reviewed, and a list of experimental demonstrations and theoretical models is presented. A simple spin model for inverse melting is introduced and solved analytically for infinite range, constant paramagnetic exchange interaction. The random exchange analogue of this model yields inverse freezing, as implied by the analytic solution based on the replica trick. The qualitative features of this system (generalized Blume-Capel spin model) are shown to resemble a large class of inverse melting phenomena. The appearance of inverse melting is related to an exact rescaling of one of the interaction parameters that measures the entropy of the system. For the case of almost degenerate spin states, perturbative expansion is presented, and the first three terms correspond to the empiric formula for the Flory-Huggins ? parameter in the theory of polymer melts. The possible microscopic origin of this ? parameter and the limitations of the Flory-Huggins theory where the state degeneracy is associated with the different conformations of a single polymer or with the spatial structures of two interacting molecules are discussed.

Schupper, Nurith; Shnerb, Nadav M.

2005-10-01

333

Special quadrature rules for Laplace transform inversion  

NASA Astrophysics Data System (ADS)

Quadrature rules for Laplace transform inversion are studied that are adapted to the inversion of transforms corresponding to slowly varying long processes characteristic of linear viscoelasticity problems. The convergence of special quadrature rules for Laplace transform inversion is proved.

Lebedeva, A. V.; Ryabov, V. M.

2012-12-01

334

Whole limb kinematics are preferentially conserved over individual joint kinematics after peripheral nerve injury  

PubMed Central

Summary Biomechanics and neurophysiology studies suggest whole limb function to be an important locomotor control parameter. Inverted pendulum and mass-spring models greatly reduce the complexity of the legs and predict the dynamics of locomotion, but do not address how numerous limb elements are coordinated to achieve such simple behavior. As a first step, we hypothesized whole limb kinematics were of primary importance and would be preferentially conserved over individual joint kinematics after neuromuscular injury. We used a well-established peripheral nerve injury model of cat ankle extensor muscles to generate two experimental injury groups with a predictable time course of temporary paralysis followed by complete muscle self-reinnervation. Mean trajectories of individual joint kinematics were altered as a result of deficits after injury. By contrast, mean trajectories of limb orientation and limb length remained largely invariant across all animals, even with paralyzed ankle extensor muscles, suggesting changes in mean joint angles were coordinated as part of a long-term compensation strategy to minimize change in whole limb kinematics. Furthermore, at each measurement stage (pre-injury, paralytic and self-reinnervated) step-by-step variance of individual joint kinematics was always significantly greater than that of limb orientation. Our results suggest joint angle combinations are coordinated and selected to stabilize whole limb kinematics against short-term natural step-by-step deviations as well as long-term, pathological deviations created by injury. This may represent a fundamental compensation principle allowing animals to adapt to changing conditions with minimal effect on overall locomotor function.

Chang, Young-Hui; Auyang, Arick G.; Scholz, John P.; Nichols, T. Richard

2009-01-01

335

Inverse DWT for Nonorthogonal Wavelets.  

National Technical Information Service (NTIS)

Discrete nonorthogonal wavelet transforms play an important role in signal processing by offering finer resolution in time and scale than their orthogonal counterparts. The standard inversion procedure for such transforms is a finite expansion in terms of...

M. J. Shensa

1993-01-01

336

Geophysical Inversion Tutorials and Workflows  

NSDL National Science Digital Library

Geophysical inversion is deriving the structure of the Earth's subsurface from data collected at the surface, using a formal 'inversion' algorithm that creates a subsurface model structure directly from the surface observations. This portal provides links to introductory articles, online tutorials, and workflows for use in geoscience tasks such as mineral exploration, geotechnical or environmental engineering. The tutorials introduce basic concepts, explain how inversion works, and include applets for modeling linear inversion and magnetic dipoles. The workflows section includes procedures for inverting DC resistivity survey data to obtain 2-dimensional models of subsurface electrical conductivity and for inverting magnetic (or gravity) survey data to obtain 3-dimensional models of subsurface magnetic susceptibility (or density) distributions. There are also links to brief summaries on survey methods, geophysical models, and a seven-step framework for carrying out geophysical surveys.

2011-07-01

337

Temperature Inversions Have Cold Bottoms.  

ERIC Educational Resources Information Center

|Uses discussion and illustrations of several demonstrations on air temperature differences and atmospheric stability to explain the phenomena of temperature inversions. Relates this to the smog in Los Angeles and discusses the implications. (DC)|

Bohren, Craig F.; Brown, Gail M.

1982-01-01

338

Inverse closedness of approximation algebras  

NASA Astrophysics Data System (ADS)

We prove the inverse closedness of certain approximation algebras based on a quasi-Banach algebra X using two general theorems on the inverse closedness of subspaces of quasi-Banach algebras. In the first theorem commutative algebras are considered while the second theorem can be applied to arbitrary X and to subspaces of X which can be obtained by a general K-method of interpolation between X and an inversely closed subspace Y of X having certain properties. As application we present some inversely closed subalgebras of and C[-1,1]. In particular, we generalize Wiener's theorem, i.e., we show that for many subalgebras S of , the property {ck(f)}[set membership, variant]S (ck(f) being the Fourier coefficients of f) implies the same property for 1/f if vanishes nowhere on .

Almira, J. M.; Luther, U.

2006-02-01

339

EXTENSION DIMENSION OF INVERSE LIMITS  

Microsoft Academic Search

Recently L.R. Rubin and P.J. Schapiro have considered inverse sequences X of metrizable spaces Xi, whose extension dimension dim Xi P , i.e., P 2 AE(Xi), where P is an arbitrary polyhedron (or CW -complex). They proved that dim X P , where X = lim X. The present paper generalizes their result to inverse sequences of stratiable spaces, giving

Sibe Marde

2000-01-01

340

Uncertainty Propagation in Calibration of Parallel Kinematic Machines  

SciTech Connect

Over the last decade, multi-axis machine tools and robots based on parallel kinematic mechanisms (PKMs) have been developed and marketed worldwide. Positional accuracy in these machines is controlled by accurate knowledge of the kinematic parameters which consists of the joint center locations and distances between joint pairs. Since these machines tend to be rather large in size, the kinematic parameters (joint center locations, and initial strut lengths) are difficult to determine when these machines are in their fully assembled state. Work recently completed by the University of Florida and Sandia National Laboratories has yielded a method for determining all of the kinematic parameters of an assembled parallel kinematic device. This paper contains a brief synopsis of the calibration method created, an error budget, an uncertainty analysis for the recovered kinematic parameters and the propagation of these uncertainties to the tool tip.

JOKIEL JR.,BERNHARD; ZIERGERT,JOHN C.

1999-11-02

341

Supersymmetry, the ILC, and the LHC inverse problem.  

SciTech Connect

We report the results of the first large scale examination of the MSSM parameter space at the International Linear Collider (ILC). In particular, we address the question of whether or not the ILC can help to resolve the LHC Inverse Problem within this context. We examine 242 randomly generated but representative points in the MSSM parameter space which were found to lead to somewhat difficult signatures at the LHC. Including full Standard Model backgrounds and a fast detector simulation, our study finds that only roughly one third of these scenarios lead to visible signatures of some kind with a significance {ge} 5 at the ILC with {radical}s = 500 GeV. However, kinematically accessible charged sparticles are visible over 90% of the time. Furthermore, we examine these points in the parameter space pairwise and find that only one third of the pairs produce distinguishable signatures at the ILC at 5{sigma}. Going to a 1 TeV center of mass energy would substantially improve this situation since the dominant limitations are kinematic in origin.

Berger, C. F.; Gainer, J. S.; Hewett, J. L.; Lillie, B. H.; Rizzo, T. G.; High Energy Physics; SLAC; MIT; Univ. of Chicago

2009-01-01

342

Geophysical diffraction tomography and waveform inversion: Applications to high resolution seismic data  

NASA Astrophysics Data System (ADS)

We apply two different techniques to analyze high resolution seismic data from surface and borehole measurements made at a groundwater contamination site at Hill Air Force Base, Ogden, Utah. Two vertical seismic profiles and surface data were recorded simultaneously in and between two 15m deep boreholes separated by 21m. The seismic source was a 223 rifle fired on the surface between the two boreholes, generating signals with energy up to ~300Hz. The size of the target area is roughly the order of a few mean wavelengths in the dataset. The relatively large ratio of mean wavelength ( ~5m) to the scale of structural detail in this high-resolution experiment (<1m) necessitates the application of diffraction tomography and waveform inversion methods. In the first method, we use a form of geophysical diffraction tomography based on the modified Kaczmarz method so that uncertainty in the data can be taken into account and other constraints can be incorporated. The forward model is a linearized Born or Rytov approximation formulated in the frequency domain. The inverse model is obtained using the modified Kaczmarz method where the relaxation parameter is a function of weights estimated from the signal/noise ratio in the data set. Using different weights the image is generated iteratively by back projecting misfits in the data space into velocity corrections in the model space. In theory, multiple-frequencies and non-uniform data sampling can be handled easily. In the second technique, full waveform inversion, the inverse problem is posed as nonlinear data fitting where the unknown parameters are solved by minimizing the misfit between the predicted data and the observed data. A gradient-type approach is applied to solve these problems in which the Jacobian and its adjoint are calculated for given model and data vectors. We present an explicit finite difference time stepping scheme to compute the forward model and its adjoint. Waveform data fitting driven by finite difference simulations can be based on different physical modeling assumptions, from acoustic to viscoelastic propagation. Our finite difference class defines an operator in the sense of the Hilbert Class Library (HCL), a C++ software package for optimization (Cockenback, and Symes, 1996). A wide range of gradient type inversion algorithms using HCL as a platform can be tested.

Gao, F.; Shen, P.; Symes, W. W.; Zelt, C. A.; Levander, A.

2001-12-01

343

Comparison of static and dynamic knee kinematics during squatting  

Microsoft Academic Search

BackgroundThere long has been debate whether static knee kinematics measured using magnetic resonance imaging are the same as knee kinematics in dynamic weight-bearing motion. Magnetic resonance imaging provides excellent volumetric detail but is static. Fluoroscopic imaging provides for dynamic observation of knee kinematics but provides no direct observation of the soft-tissue structures. We attempted to answer the question ‘Are knee

S. Mu; T. Moro-oka; P. Johal; S. Hamai; M. A. R. Freeman; S. A. Banks

2011-01-01

344

On the kinematic evolution of flare-associated cmes  

Microsoft Academic Search

We report a common tendency of the kinematic evolution of three flare-associated coronal mass ejections (CMEs). Their kinematic evolutions are examined using well-observed data (eruptive filaments, X-ray structures, and prominences) very close to the solar surface as well as SOHO\\/LASCO C2-C3 data. Their height–time data are fitted using three analytical models (exponential, power-law, and linear) to examine their kinematic behaviors.

A. Shanmugaraju; Y.-J. Moon; M. Dryer; S. Umapathy

2003-01-01

345

Kinematic synthesis of cam-controlled planetary gear trains  

Microsoft Academic Search

In this work, a systematic approach for the kinematic synthesis of cam-controlled planetary gear trains (CCPGTs) is proposed. First, structural synthesis of (4,5) kinematic chains is performed. Furthermore, kinematic analysis is conducted from its geometry. Moreover, the B-spline-based motion design approach is presented. Finally, cam profile equations for the new design are derived. In addition, two design examples are illustrated.

Wen-Hsiang Hsieh

2009-01-01

346

Early-type gal. kinematics in compact groups (Bonfanti+, 1999)  

NASA Astrophysics Data System (ADS)

We present measurements of stellar kinematics for seven early-type galaxies in HCG 67, HCG 74, and HCG 79. These data are aimed at studying the relation between the environment and the dynamics, structure and stellar content of early-type galaxies. In the present three groups, the kinematic features we observed cannot be associated unambiguously to physical interactions. Visible morphological peculiarities do not appear correlated with kinematical perturbations. (2 data files).

Bonfanti, P.; Simien, F.; Rampazzo, R.; Prugniel, P.

1999-10-01

347

A Kinematical Approach to Dark Energy Studies  

SciTech Connect

We present and employ a new kinematical approach to cosmological ''dark energy'' studies. We construct models in terms of the dimensionless second and third derivatives of the scale factor a(t) with respect to cosmic time t, namely the present-day value of the deceleration parameter q{sub 0} and the cosmic jerk parameter, j(t). An elegant feature of this parameterization is that all {Lambda}CDM models have j(t) = 1 (constant), which facilitates simple tests for departures from the {Lambda}CDM paradigm. Applying our model to the three best available sets of redshift-independent distance measurements, from type Ia supernovae and X-ray cluster gas mass fraction measurements, we obtain clear statistical evidence for a late time transition from a decelerating to an accelerating phase. For a flat model with constant jerk, j(t) = j, we measure q{sub 0} = -0.81 {+-} 0.14 and j = 2.16{sub -0.75}{sup +0.81}, results that are consistent with {Lambda}CDM at about the 1{sigma} confidence level. A standard ''dynamical'' analysis of the same data, employing the Friedmann equations and modeling the dark energy as a fluid with an equation of state parameter, w (constant), gives {Omega}{sub m} = 0.306{sub -0.040}{sup +0.042} and w = -1.15{sub -0.18}{sup +0.14}, also consistent with {Lambda}CDM at about the 1{sigma} level. In comparison to dynamical analyses, the kinematical approach uses a different model set and employs a minimum of prior information, being independent of any particular gravity theory. The results obtained with this new approach therefore provide important additional information and we argue that both kinematical and dynamical techniques should be employed in future dark energy studies, where possible. Our results provide further interesting support for the concordance {Lambda}CDM paradigm.

Rapetti, David; Allen, Steven W.; Amin, Mustafa A.; Blandford, Roger D.; /KIPAC, Menlo Park

2006-06-06

348

Kinematic Rupture Process Of Karakocan-Elazig Earthquake, Eastern Turkey  

NASA Astrophysics Data System (ADS)

An earthquake (Mw=5.9) hit Elazig in the eastern part of Turkey on March 8, 2010 at 02:32 (GMT). It is located midway between the provincial capital of Elaz?? and Bingöl with coordinates reported as 38o48.42N and 40o5.99E by Bogazici University Kandilli Observatory and Earthquake Research Institute (KOERI). Source characterization and slip history were estimated the main and four moderate size earthquake almost at the same location. The earthquake occurred at one of the tectonically very active East Anatolian Fault zone starts at the Karl?ova triple junction, where it meets the North Anatolian fault to the NE. Multi time-window linear waveform inversion technique (MTWIT) was applied to strong ground motion (SGM) data. Theoretical Green's functions between subfaults and stations were calculated by a Discrete Wave Number Method (DWNM) using 1-D velocity structure. Inversion technique used in this study yields a non unique solution. Therefore various rupture models have been tried until both observed and synthetic data were matched. Results show simple patterns in slip distributions. Maximum slip is 0.78 and seismic moment is 1.435E+25 dyne.cm from the kinematic rupture process of the strike slip faulting. In this study, we searched a stable 1-D crustal velocity model with low RMS misfit to construct the theoretical Green's function between each sub-fault and each station among the 4 different models. These are Preliminary Reference Earth Model (PREM; Dziewonski and Anderson, 1981), International Association of Seismology and the Physics of the Earth's Interior (IASP91) (Kennett and Engdahl, 1991), Kandilli Observatory and Earthquake Research Institute (KOERI) earthquake location model, explosion model (Gurbuz, 2004). We have collected previous studies Rebollar et al., (2001), Ichinose et al., (1997), Abdel-Fattah (2002), Somerville et al., (1999), Wells and Coppersmith (1994) on source information of moderate size earthquakes occurred worldwide and compared with our results. Results were compared with those of similar size earthquakes around the world and a new empirical relationship was proposed between seismic moment and rupture area. We expect our findings provide usefull information to resolving rupture mechanisms and triggering of the events in Eastern Anatoion Region. Key Words: Rupture Process, Elazig Earthquake, Eastern Turkey

Bekler, F. N.; Ozel, N. M.; Tanircan, G. B.

2012-04-01

349

Quantum simulation of noncausal kinematic transformations.  

PubMed

We propose the implementation of Galileo group symmetry operations or, in general, linear coordinate transformations in a quantum simulator. With an appropriate encoding, unitary gates applied to our quantum system give rise to Galilean boosts or spatial and time parity operations in the simulated dynamics. This framework provides us with a flexible toolbox that enhances the versatility of quantum simulation theory, allowing the direct access to dynamical quantities that would otherwise require full tomography. Furthermore, this method enables the study of noncausal kinematics and phenomena beyond special relativity in a quantum controllable system. PMID:24033011

Alvarez-Rodriguez, U; Casanova, J; Lamata, L; Solano, E

2013-08-28

350

Elbow Position Affects Distal Radioulnar Joint Kinematics  

PubMed Central

Previous in vivo and in vitro studies of forearm supination/pronation suggest that distal radioulnar joint kinematics may be affected by elbow flexion. The primary hypotheses tested by this study were that in vivo: 1) ulnar variance changes with elbow flexion and forearm rotation and 2) the arc of forearm rotation changes in relationship to elbow flexion. Materials and Methods Changes in radioulnar kinematics during forearm supination/pronation and elbow flexion (0–90°) were studied in five uninjured subjects using computed tomography, dual-orthogonal fluoroscopy, and three-dimensional modeling. Analysis of variance and post-hoc testing was performed. Results Proximal translation of the radius was greatest with the elbow flexed to 90° with the arm in mid-pronation. With the arm in mid-pronation, the translation of the radius was significantly greater at 0° versus 45° of elbow flexion (0.82 ± 0.59 mm v. 0.65 ± 0.80 mm, F: 4.49, Post Hoc: 0.055; p = 0.05), and significantly smaller at 45° versus 90° of elbow flexion (0.65 ± 0.80 mm v. 0.97 ± 0.35 mm, F: 4.49, Post Hoc: 0.048; p = 0.05). Proximal translation of the radius in mid-pronation was significantly greater than when the forearm was in a supinated position when the elbow was at 0° or 90° flexion (F: 14.90, post-hoc: < 0.01; p < 0.01, F: 19.11, post-hoc: < 0.01, p < 0.01). The arc of forearm rotation was significantly decreased at 0° compared to 90° of elbow flexion (129.3 ± 22.2° v 152.8 ± 14.4°, F: 3.29, post-hoc: 0.79; p = 0.09). The center of rotation shifted volarly and ulnarly with increasing elbow extension. Discussion Elbow position affects the kinematics of the distal radioulnar joint. The kinematics of the distal radioulnar joint are primarily affected by forearm rotation and secondarily affected by elbow flexion. These findings have clinical relevance to our understanding of ulnar impaction, and how elbow position affects the proximal-distal translation of the radius. These findings have implications upon the treatment of ulna impaction, radiographic evaluation of the distal ulna, and future biomechanical studies.

Fu, Eric; Li, Guoan; Souer, Sebastiaan; Lozano-Calderon, Santiago; Herndon, James H.; Jupiter, Jesse B.; Chen, Neal C.

2009-01-01

351

Physics Suite Peer Instruction Problems: Kinematics  

NSDL National Science Digital Library

This website contains a series of peer instruction problems on kinematics, designed to be solved in a classroom setting. The problems are presented with a qualitative (usually multiple choice) question that is carefully constructed to engage student difficulties with fundamental concepts. Students consider the problem individually and contribute their answers using personal response systems (clickers). Students then confer with their cooperative groups and vote again on the correct response. Topics covered include displacement, velocity, average velocity, speed, and interpreting position and velocity graphs. This problem set is part of the Physics Suite collection, containing sample problems, peer instruction problems, and alternative homework sets.

Redish, Edward F.

2008-08-11

352

AAPT/PTRA Teaching About Kinematics  

NSDL National Science Digital Library

This AAPT/PTRA Teacher Resource Guide covers approaches to teaching and learning kinematics. Based on physics education research, the book provides teachers with the resources needed to introduce students to concepts in motion through step-by-step laboratory-based instruction. Inquiry, measurement, and analysis of laboratory data are emphasized throughout. This book includes materials on measurement of time and space and the distinctions between speed, velocity, and three types of acceleration. It includes laboratory activities, worksheets, transparency masters, teacher notes, typical answers to questions, and helpful hints by master teachers.

Nelson, Jane; Nelson, Jim

2011-01-04

353

Overview of kinematic variables in top production  

SciTech Connect

A selection of simple kinematic variables chosen to be sensitive to different aspects of {ital t{anti t}} production in W + {>=} 3 jets events are studied. Monte Carlo comparisons are made between different top generators (Herwig, Pythia, and Isajet) and a QCD background generator (VECBOS). Finally, Monte Carlo predictions with the {ital t{anti t}} fraction constrained by the SVX {ital b}-tagging rate and measured top mass are compared with 110 pb{sup -1} of CDF data. We conclude that the CDF data is consistent with standard predictions using the studied generators.

Binkley, M.; Beretvas, A.; CDF Collaboration

1996-09-01

354

Exclusive electroproduction revisited: Treating kinematical effects  

SciTech Connect

Generalized parton distributions of the nucleon are accessed via exclusive leptoproduction of the real photon. While earlier analytical considerations of phenomenological observables were restricted to twist-three accuracy, i.e., taking into account only terms suppressed by a single power of the hard scale, in the present study we revisit this differential cross section within the helicity formalism and restore power-suppressed effects stemming from the process kinematics exactly. We restrict ourselves to the phenomenologically important case of lepton scattering off a longitudinally polarized nucleon, where the photon flips its helicity at most by one unit.

Belitsky, A. V. [Department of Physics, Arizona State University, Tempe, Arizona 85287-1504 (United States); Mueller, D. [Institut fuer Theoretische Physik II, Ruhr-Universitaet Bochum, D-44780 Bochum (Germany)

2010-10-01

355

Kinematics of the CSE in VY CMa  

NASA Astrophysics Data System (ADS)

We report on astrometric results of H2O and SiO masers in the circumstellar envelopes of VY Canis Majoris (VY CMa) carried out with VERA for 2 years. Absolute positions and proper motions of 3 different frequencies of masers were measured with phase-referencing analyses. Using the positions and the 3-dimensional velocities of the masers, we considered the 3-dimensional structures and kinematics of the circumstellar envelopes around VY CMa. The H2O masers show bipolar outflow along the line of sight, and the SiO masers have both expanding and contracting motions with less than 5 km/s.

Choi, Yoon Kyung

2009-07-01

356

Mapping Dark Matter Halos with Stellar Kinematics  

NASA Astrophysics Data System (ADS)

Galaxies of all sizes form and evolve in the centers of dark matter halos. As these halos constitute the large majority of the total mass of a galaxy, dark matter certainly plays a central role in the galaxy's formation and evolution. Yet despite our understanding of the importance of dark matter, observations of the extent and shape of dark matter halos have been slow in coming. The paucity of data is particularly acute in elliptical galaxies. Happily, concerted effort over the past several years by a number of groups has been shedding light on the dark matter halos around galaxies over a wide range in mass. The development of new instrumentation and large surveys, coupled with the tantalizing evidence for a direct detection of dark matter from the AMS experiment, has brought on a golden age in the study of galactic scale dark matter halos. I report on results using extended stellar kinematics from integrated light to dynamically model massive elliptical galaxies in the local universe. I use the integral field power of the Mitchell Spectrograph to explore the kinematics of stars to large radii (R > 2.5 r_e). Once the line-of-sight stellar kinematics are measured, I employ orbit-based, axisymmetric dynamical modeling to explore a range of dark matter halo parameterizations. Globular cluster kinematics at even larger radii are used to further constrain the dynamical models. The dynamical models also return information on the anisotropy of the stars which help to further illuminate the primary formation mechanisms of the galaxy. Specifically, I will show dynamical modeling results for the first and second rank galaxies in the Virgo Cluster, M49 and M87. Although similar in total luminosity and ellipticity, these two galaxies show evidence for different dark matter halo shapes, baryon to dark matter fractions, and stellar anisotropy profiles. Moreover, the stellar velocity dispersion at large radii in M87 is significantly higher than the globular clusters at the same radial extent, reinforcing the need for broad comparisons between the different methods and assumptions underlying the dynamical analysis of massive ellipticals.

Murphy, Jeremy; Gebhardt, K.; Greene, J. E.; Graves, G.

2013-07-01

357

Automobile Collisions, Kinematics and Related Injury Patterns  

PubMed Central

It has been determined clinically that fatalities and injury severity resulting from automobile collisions have decreased during the last five years for low impact speeds. This reduction is a direct result of the application of biomechanics and occupant kinematics, as well as changes in automobile design. The paper defines terminology used in the field of mechanics and develops examples and illustrations of the physical concepts of acceleration, force strength, magnitude duration, rate of onset and others, as they apply to collision phenomena and injury. The mechanism of injury pattern reduction through the use of restraint systems is illustrated.

Siegel, A. W.

1972-01-01

358

Quantum Simulation of Noncausal Kinematic Transformations  

NASA Astrophysics Data System (ADS)

We propose the implementation of Galileo group symmetry operations or, in general, linear coordinate transformations in a quantum simulator. With an appropriate encoding, unitary gates applied to our quantum system give rise to Galilean boosts or spatial and time parity operations in the simulated dynamics. This framework provides us with a flexible toolbox that enhances the versatility of quantum simulation theory, allowing the direct access to dynamical quantities that would otherwise require full tomography. Furthermore, this method enables the study of noncausal kinematics and phenomena beyond special relativity in a quantum controllable system.

Alvarez-Rodriguez, U.; Casanova, J.; Lamata, L.; Solano, E.

2013-08-01

359

Kinematic Measurements from YouTube Videos  

NASA Astrophysics Data System (ADS)

Video analysis of motion has been in use now for some time.1-3 However, some teachers may not have video equipment or may be looking for innovative ways to engage students with interesting applications at no cost. The recent advent of YouTube offers opportunities for students to measure kinematic properties of real-life events using their computers. This paper provides examples such as measuring the average speed of a winning horse at the Kentucky Derby, plotting speed versus time from watching the speedometer of a high-performance bike, and determining acceleration for circular motion of amusement park rides.

Ruiz, Michael J.

2009-04-01

360

Kinematics of the South Atlantic rift  

NASA Astrophysics Data System (ADS)

Extensional deformation along the South Atlantic, Central African and West Africa rift systems heralded in the breakup of the western half of the Gondwana supercontinent. The interplay between a complex series of intraplate rifts profoundly affected the spatio-temporal localisation of extensional deformation and the resulting geometries of the conjugate South Atlantic margins. We present a new plate kinematic model which quantitatively integrates lithosphere deformation and observations from both passive margins and intracontinental rifts in Africa and South America. Our model eliminates the need for previously inferred large offset continental shear zones in southern South America such as the Gastre Fault system while satisfying most observations of the onset of subsidence, deformation and rifting along the conjugate rifted margins and related marginal sedimentary basins. The model indicates that extension became focussed in the South Atlantic rift basin by the Earliest Cretaceous, continuing at low extensional velocities, predominantly controlled by African intraplate deformation while there was no deformation along the future Equatorial Atlantic. The Patagonian part of South America acted as an independent plate between Antarctica, Africa, and South America during the Latest Jurassic to Aptian times, hereby opening rift basins striking at high angles to the present-day South American margin. By about 125 Ma (Barremian/Aptian) deformation and subsequent weakening along the Equatorial Atlantic rift branch yielded a large increase in extensional velocities and a change in extension direction between South America and Africa, while lithospheric extension had progressed far enough to create the enigmatic sub-salt basins in the central South Atlantic. The change in spreading direction largely eliminated intraplate deformation in Patagonia and subsequently resulted in the onset of post-rift thermal subsidence in the southern South American basins. Rupture of extended continental lithosphere in the central South Atlantic followed a few million years after this major change in kinematics and is likely responsible for the observed first-order present day margin geometry. We compare our model-derived kinematics against predictions from forward numerical models of lithosphere extension along the conjugate West-African/Brazil and the Equatorial Atlantic margins. We conclude that the multi-velocity, multi-directional rift history can consistently explain the first order margin geometry observed in the South Atlantic. We further couple our plate kinematic model with predictive forward mantle flow models that integrate lithospheric deformation to test the influence of mantle-driven topography on the evolving rift.

Heine, C.; Brune, S.; Young, A.; Zoethout, J.; Flament, N.; Müller, R. D.

2012-04-01

361

Kinematical and mechanical aspects of wafer slicing  

NASA Astrophysics Data System (ADS)

Some recently achieved results concerning the technological fundamentals of slurry sawing are presented. The specific material removal process and the related kinematic and geometric contact conditions between workpiece and saw blade are described. The result of a functional description of the slurry sawing process is presented, expressing the main process criteria, such as infeed per stroke, specific removal rate, specific tool wear, and vertical stroke intensity, in terms of the dominating process parameters, such as stroke length, width of workpiece, stroke frequency, specific cutting force and slurry specification.

Werner, P. G.

1982-02-01

362

On the internal kinematics of PNe  

NASA Astrophysics Data System (ADS)

Our sample of round/elliptical double-shell PNe around central stars (CSs) with H-rich surface chemistry covers all evolutionary phases across the HRD. By means of high-resolution and high-S/N spectra we determine bulk matter velocities of the inner wind-driven rims and the maximum (= post-shock) gas velocities of the surrounding thermally expanding shells. Studying the details of the internal kinematics allows a look at processes of PN formation and at PN expansion history helping, for instance, to determine expansion distances.

Jacob, Ralf; Schönberner, Detlef; Lehmann, Holger; Zwanzig, Alena; Sandin, Christer; Steffen, Matthias

2012-08-01

363

A new approach for modelling kinematic dependencies for monitoring locations of objects in closed kinematic chains. (Part 2).  

PubMed

Location monitoring systems for surgical applications are getting more and more common in clinical daily life. Navigation treatment systems are also a form of a location monitoring system. These systems always consist of an optical, US-, electromagnetic or mechanical navigation system. If two or more navigation systems are combined or one navigations system is combined with a robot system the kinematic model of the entire system consists of closed kinematic loops. In this paper, an approach is presented to gain more information from the closed kinematic chains instead of breaking the kinematic loops. This is the second part of [1]. PMID:15458141

Stien, Malte; Hein, Andreas; Szymanski, Daniel; Lueth, Tim

2002-01-01

364

Kinematic Nuclear Masses of Very Luminous Galaxies  

NASA Astrophysics Data System (ADS)

We have used high resolution infrared spectroscopy to measure the mass in the nuclear regions of five very luminous infrared galaxies: NGC 1614, NGC 3690, IC 694, NGC 6240, and Zw 475.056. The masses were determined from the kinematics of the stellar component. We used FSpec at the Steward Observatory 2.3 m telescope to observe the 2.3 microns CO bandhead at a resolution of 3500. Our methods were validated by observations of M 31, whose nuclear kinematics are well understood. We are testing whether the H2 masses derived from mm CO observations are realistic by comparing them to our dynamical masses. We have are using the mass to bolometric luminosity ratio to determine if enough mass is present to allow a stellar origin for all of the luminosity. At least some of the galaxies we observed may be powered entirely by a starburst. The strength of the CO bands suggest that the K band flux is dominated by stars, not hot dust or an AGN. LMS thanks NASA for support through the Graduate Student Researchers Program. FSpec is supported by NSF grant AST-9116442.

Shier, L. M.; Rieke, M. J.

1993-12-01

365

Pauli Villars regularization and Born Infeld kinematics  

NASA Astrophysics Data System (ADS)

Dynamical symmetries of Born Infeld theory can be absorbed into the spacetime geometry, giving rise to relativistic kinematics with an additional invariant acceleration scale. The standard Poincaré group Script P is thereby enhanced to its pseudo-complexified version, which is isomorphic to Script P × Script P. We construct the irreducible representations of this group, which yields the particle spectrum of a relativistic quantum theory that respects a maximal acceleration. It is found that each standard relativistic particle is associated with a 'pseudo'-partner of equal spin but generically different mass. These pseudo-partners act as Pauli Villars regulators for the other member of the doublet, as is found from the explicit construction of quantum field theory on pseudo-complex spacetime. Conversely, a Pauli Villars regularized quantum field theory on real spacetime possesses a field phase space with integrable pseudo-complex structure, which gives rise to a quantum field theory on pseudo-complex spacetime. This equivalence between maximal acceleration kinematics, pseudo-complex quantum field theory and Pauli Villars regularization rigorously establishes a conjecture on the regularizing property of the maximal acceleration principle in quantum field theory, by Nesterenko, Feoli, Lambiase and Scarpetta.

Schuller, Frederic P.; Wohlfarth, Mattias N. R.; Grimm, Thomas W.

2003-10-01

366

Star cluster kinematics in the GAIA era  

NASA Astrophysics Data System (ADS)

The {GAIA} astrometric satellite will measure positions, proper motions and parallaxes of millions of stars with micro-arcsecond accuracy. This will greatly increase our understanding of the stellar populations of the Milky Way and their dynamics. In particular, it will be possible to determine internal and space motions of a large number of open or globular clusters with an accuracy of a few km/s or better, which will bring new insights into the way star clusters evolve and how they and the Milky Way as a whole have formed. It will also be possible to look for clusters which have a common space motion and follow tidal streams from dissolving globular clusters over many orbits by kinematically selecting their members, which will constrain the form of the galactic potential. I illustrate how {GAIA} will improve our knowledge on the kinematics and dynamics of star clusters and what can be learned by comparing the {GAIA} data with realistic N-body simulations of star clusters, possible with e.g. future GPU or GRAPE computers.

Baumgardt, H.

2008-12-01

367

Maximum likelihood estimation of local stellar kinematics  

NASA Astrophysics Data System (ADS)

Context. Kinematical data such as the mean velocities and velocity dispersions of stellar samples are useful tools to study galactic structure and evolution. However, observational data are often incomplete (e.g., lacking the radial component of the motion) and may have significant observational errors. For example, the majority of faint stars observed with Gaia will not have their radial velocities measured. Aims: Our aim is to formulate and test a new maximum likelihood approach to estimating the kinematical parameters for a local stellar sample when only the transverse velocities are known (from parallaxes and proper motions). Methods: Numerical simulations using synthetically generated data as well as real data (based on the Geneva-Copenhagen survey) are used to investigate the statistical properties (bias, precision) of the method, and to compare its performance with the much simpler "projection method" described by Dehnen & Binney (1998, MNRAS, 298, 387). Results: The maximum likelihood method gives more correct estimates of the dispersion when observational errors are important, and guarantees a positive-definite dispersion matrix, which is not always obtained with the projection method. Possible extensions and improvements of the method are discussed.

Aghajani, T.; Lindegren, L.

2013-03-01

368

Seismic constraints in magnetotelluric inversion  

NASA Astrophysics Data System (ADS)

Non-uniqueness is one of the least governable features in inversion of geophysical data, and magnetotelluric models obtained from inversion are dramatically affected by problems of non-uniqueness. In order to reduce the dimension of acceptable model space in which the inversion model is selected, several solutions have been proposed with different degree of success, usually by introducing some regularization terms in the defined objective function. In our present scheme, information from a seismic inversion is integrated in the inversion process in order to reduce non-uniqueness of solutions and to improve the robustness of the inversion results. The inversion scheme is implemented by including in the objective function a term that maximizes the mutual information between the reference (in this case seismic) model and the electromagnetic model, so that it is possible to plot an empirical histogram that maps phase velocity in electrical conductivity in the considered profile. In probability and information theory the mutual information of two random variables is a quantity that measures their mutual dependence. Given a reference image, in this work a seismic profile, and a second image which needs to be put in the same coordinate system as the reference image, this image is deformed until the mutual information between it and the reference image is maximized. In this way the inversion scheme is driven to fit magnetotelluric data and to take the most possible advantage from seismic information available from the profile. Using this approach it is possible to use a linearized inversion scheme to invert data from a highly non-linear problem like magnetotellurics, keeping it in its whole complexity and obtaining results that allows appreciation of the empirical coupling between the reference image and the obtained (MT) model. Any reference model can be used in our approach during the inversion process, making this scheme suitable to use a reference model produced by a wide range of geophysical or other geoscientific methods. The scheme is applied to synthetic data, but an interesting improvement in the inversion results - particularly reducing artefact constructs beneath areas of high resistivity - is highlighted and can be appreciated. Inverted data are generated from synthetic models that are compatible with the seismic reference, but it is interesting note that it is not required to generate data from a model that shares exactly the same structure as the reference one. What is needed is a model that can be mapped in the reference one following a transformation without too many singularities. Also the robustness of the solution found is improved and less dependent on the starting model. In this sense it is possible to state that the term introduced in the objective function operate as a good constraint in the inversion process, reducing problems caused in the interpretation stage from non-uniqueness of magnetotelluric problem.

Mandolesi, E.; Jones, A. G.

2010-12-01

369

Population inversion by chirped pulses  

SciTech Connect

In this paper, we analyze the condition for complete population inversion by a chirped pulse over a finite duration. The nonadiabatic transition probability is mapped in the two-dimensional parameter space of coupling strength and detuning amplitude. Asymptotic forms of the probability are derived by the interference of nonadiabatic transitions for sinusoidal and triangular pulses. The qualitative difference between the maps for the two types of pulses is accounted for. The map is used for the design of stable inversion pulses under specific accuracy thresholds.

Lu Tianshi [Department of Mathematics and Statistics, Wichita State University, Wichita, Kansas 67260-0033 (United States)

2011-09-15

370

Uncertainty Propagation in Calibration of Parallel Kinematic Machines; Precision Engineering, American Society for Precision Engineering (ASPE).  

National Technical Information Service (NTIS)

Uncertainty Propagation in Calibration of Parallel Kinematic Machines joint center locations and distances be rather large in size, the kinematic parameters (joint center locations, and initial strut lengths) for determining all of the kinematic parameter...

Jokiel Ziergert

1999-01-01

371

A School Experiment in Kinematics: Shooting from a Ballistic Cart  

ERIC Educational Resources Information Center

|Many physics textbooks start with kinematics. In the lab, students observe the motions, describe and make predictions, and get acquainted with basic kinematics quantities and their meaning. Then they can perform calculations and compare the results with experimental findings. In this paper we describe an experiment that is not often done, but is…

Kranjc, T.; Razpet, N.

2011-01-01

372

Kinematic parameters estimation of robot motion using active vision  

Microsoft Academic Search

The authors address the problem of estimating the distance and velocity, between a mobile robot and an obstacle. The goal is to determine the kinematic parameters of the relative motion to build an effective avoidance motion. The information issued from a camera coupled with a laser stripe is used to estimate the kinematic parameters with an extended Kalman filter (EKF).

D. Monteiro; B. Jouvencel; R. Zapata

1992-01-01

373

A medical robot kinematics design approach based on knowledge management  

Microsoft Academic Search

Purpose – The purpose of this paper is to present a methodology for medical robot kinematics design developed using a knowledge-management approach. Design\\/methodology\\/approach – A classification of medical robots is proposed based on their kinematic characteristics and 76 robot specifications were collected in a catalogue. Then, having drawn a generic specifications sheet, rules were proposed to choose a structure from

Natalie Smith-Guerin; Laurence Nouaille; Pierre Vieyres; Gerard Poisson

2008-01-01

374

Lingual Kinematics during Rapid Syllable Repetition in Parkinson's Disease  

ERIC Educational Resources Information Center

|Background: Rapid syllable repetition tasks are commonly used in the assessment of motor speech disorders. However, little is known about the articulatory kinematics during rapid syllable repetition in individuals with Parkinson's disease (PD). Aims: To investigate and compare lingual kinematics during rapid syllable repetition in dysarthric…

Wong, Min Ney; Murdoch, Bruce E.; Whelan, Brooke-Mai

2012-01-01

375

Kinematics and Dynamic Stability of the Locomotion of Polio Patients  

Microsoft Academic Search

The study reported in this article was conducted to propose a set graphical and analytical tools and assess their clinical utility by analyzing gait kinematics and dynamics of polio survivors. Phase plane portraits and first return maps were used as graphical tools to detect abnormal patterns in the sagittal kinematics of polio gait. Two new scalar measures were introduced to

Yildirim Hurmuzlu; Cagatay Basdogan; Dan Stoianovici

2001-01-01

376

A School Experiment in Kinematics: Shooting from a Ballistic Cart  

ERIC Educational Resources Information Center

Many physics textbooks start with kinematics. In the lab, students observe the motions, describe and make predictions, and get acquainted with basic kinematics quantities and their meaning. Then they can perform calculations and compare the results with experimental findings. In this paper we describe an experiment that is not often done, but is…

Kranjc, T.; Razpet, N.

2011-01-01

377

The neglected science of motion: The kinematic origins of relativity  

Microsoft Academic Search

This dissertation elucidates conceptual and mathematical roots of Albert Einstein's special theory of relativity of 1905 by analyzing its emergence in light of the history of kinematics, the science of motion. In the first volume, I trace the development of kinematics, mainly during the nineteenth century, to show how physicists came to regard it as the fundamental branch of physics.

Alberto Antonio Martinez

2001-01-01

378

Kinematic Signatures of Telic and Atelic Events in ASL Predicates  

ERIC Educational Resources Information Center

|This article presents an experimental investigation of kinematics of verb sign production in American Sign Language (ASL) using motion capture data. The results confirm that event structure differences in the meaning of the verbs are reflected in the kinematic formation: for example, in the telic verbs (throw, hit), the end-point of the event is…

Malaia, Evie; Wilbur, Ronnie B.

2012-01-01

379

The Schwarzchild Kinematical Explorer (SKE): A Proposed Midex Mission  

Microsoft Academic Search

The Schwarzchild Kinematical Explorer (SKE) is a proposed midex mission with a telescope aperture that is larger than HST which will perform two large kinematical studies. Both studies will survey at least 200 galaxies in 2-dimensional spectrographic mode with a spatial resolution that is twice that of HST. The first survey will study the supermassive black holes in the cores

C. L. Joseph

2000-01-01

380

Interactive Integration of Ballistic Dynamics with Kinematic Animation  

Microsoft Academic Search

We present an interactive system for editing rigid-body animations that contain both physically simulated and kinematically driven ob- jects interacting via collisions. Users can modify simulated body's state after a collision, and the kinematic body's motion will ad- just accordingly through motion warping. We implement one pos- sible application, in which a motion-captured animation of a soccer player is edited

Daniel Vlasic; Matthew Grimes

381

Kinematics and interaction analysis for tracked mobile manipulators  

Microsoft Academic Search

This paper presents a systematic method to establish the kinematics model for a tracked mobile manipulator on firm grounds, with consideration of the interactive motions between the tracks and the terrain as well as those between the tracked vehicle and the onboard manipulator. Kinematics modeling for a tracked mobile manipulator is an intractable problem, because there are infinite number of

Yugang Liu; Guangjun Liu

2007-01-01

382

Foot orthotics affect lower extremity kinematics and kinetics during running  

Microsoft Academic Search

Objective. To quantify the effects of posting and custom-molding of foot orthotics on lower extremity kinematics and kinetics during running. Design. Repeated measures. Background. Several kinematic and kinetic factors have been suggested to increase a runners risk for injuries. It has been speculated that foot orthotics can be used to reduce injury related complaints or even prevent running injuries by

Anne M; Benno M. Nigg; R. Neil Humble; Darren J. Stefanyshyn

2003-01-01

383

A New Assessment of Singularities of Parallel Kinematic Chains  

Microsoft Academic Search

This paper presents a novel assessment of singularities of general parallel kinematic chains. Hierarchical levels in which different critical phenomena originate are recognized. At each level, the causes of singular events are identified and interpreted, and on their basis, a comprehensive taxonomy is proposed. First, the unactuated kinematic chain is studied. The concepts of leg and passive-constraint singularities are described,

Michele Conconi; Marco Carricato

2009-01-01

384

Measurement of lumbar spine kinematics in incline treadmill walking  

Microsoft Academic Search

A study was undertaken to analyse and compare the pelvic (S1) and the trunk (T12) oscillations during level and uphill walking and to provide kinematic baseline data of the lumbar region in incline walking for future comparisons with pathological gait patterns. An ultrasonic movement analysis device (Zebris® CMS 50) was used to obtain three-dimensional kinematic data for the pelvis and

L. Vogt; W. Banzer

1999-01-01

385

The use of functional analysis in evaluating knee kinematics.  

PubMed

The importance of understanding the six-degrees-of-freedom kinematics of the knee during ambulatory activities was examined in the context of the function of total knee arthroplasty. Studies of knee kinematics during walking, stair climbing, and a deep flexion squat indicate that knee kinematics is activity-dependent. A comparative study of patients and healthy subjects during stair climbing indicates the importance of maintaining the function of the posterior cruciate ligament. A second study used walking kinematics derived from patient testing as input to a wear simulator. There was increased wear relative to standard simulator input that was related to the slip velocity at the contact surface. Finally, results from a study of deep flexion indicate that substantial femoral rotation is required during deep flexion activities. The current study shows the importance of studying in vivo knee kinematics for future enhancement in the treatment of the arthritic knee. PMID:12771816

Andriacchi, Thomas P; Dyrby, Chris O; Johnson, Todd S

2003-05-01

386

Kinematics of the South Atlantic rift  

NASA Astrophysics Data System (ADS)

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 equatorial Atlantic domain, resulting in both progressively increasing extensional velocities as well as a significant rotation of the extension direction to NE-SW. From Base Aptian onwards diachronous lithospheric breakup occurred along the central South Atlantic rift, first in the Sergipe-Alagoas/Rio Muni margin segment in the northernmost South Atlantic. Final breakup between South America and Africa occurred in the conjugate Santos-Benguela margin segment at around 113 Ma and in the Equatorial Atlantic domain between the Ghanaian Ridge and the Piauí-Ceará margin at 103 Ma. We conclude that such a multi-velocity, multi-directional rift history exerts primary control on the evolution of this conjugate passive margins systems and can explain the first order tectonic structures along the South Atlantic and possibly other passive margins.

Heine, C.; Zoethout, J.; Müller, R. D.

2013-01-01

387

Deployable antenna kinematics using tensegrity structure design  

NASA Astrophysics Data System (ADS)

With vast changes in spacecraft development over the last decade, a new, cheaper approach was needed for deployable kinematic systems such as parabolic antenna reflectors. Historically, these mesh-surface reflectors have resembled folded umbrellas, with incremental redesigns utilized to save packaging size. These systems are typically over-constrained designs, the assumption being that high reliability necessary for space operations requires this level of conservatism. But with the rapid commercialization of space, smaller launch platforms and satellite buses have demanded much higher efficiency from all space equipment than can be achieved through this incremental approach. This work applies an approach called tensegrity to deployable antenna development. Kenneth Snelson, a student of R. Buckminster Fuller, invented Tensegrity structures in 1948. Such structures use a minimum number of compression members (struts); stability is maintain using tension members (ties). The novelty introduced in this work is that the ties are elastic, allowing the struts to extend or contract, and in this way changing the surface of the antenna. Previously, the University of Florida developed an approach to quantify the stability and motion of parallel manipulators. This approach was applied to deployable, tensegrity, antenna structures. Based on the kinematic analyses for the 3-3 (octahedron) and 4-4 (square anti-prism) structures, the 6-6 (hexagonal anti-prism) analysis was completed which establishes usable structural parameters. The primary objective for this work was to prove the stability of this class of deployable structures, and their potential application to space structures. The secondary objective is to define special motions for tensegrity antennas, to meet the subsystem design requirements, such as addressing multiple antenna-feed locations. This work combines the historical experiences of the artist (Snelson), the mathematician (Ball), and the space systems engineer (Wertz) to develop a new, practical design approach. This kinematic analysis of tensegrity structures blends these differences to provide the design community with a new approach to lightweight, robust, adaptive structures with the high reliability that space demands. Additionally, by applying Screw Theory, a tensegrity structure antenna can be commanded to move along a screw axis, and therefore meeting the requirement to address multiple feed locations.

Knight, Byron Franklin

388

Kinematic analysis of reaching in the cat.  

PubMed

The present study examines the kinematic features of forelimb movements made by cats reaching for food in horizontal target wells located at different heights and distances. Wrist paths consisted of two relatively straight segments joined at a "via-point" in front of the aperture of the food well. In the initial lift phase, the paw was raised to the via-point in front of the target. In the second, or thrust phase, the paw was directed forward into the food well. During the lift, the paw was moved toward the target primarily by elbow flexion, accompanied by a sequence of biphasic shoulder and wrist movements. Thrust was accomplished primarily by shoulder flexion while the wrist and the paw were maintained at near-constant angles. The animals varied the height of the reach primarily by varying elbow flexion with proportional changes in elbow angular velocity and angular acceleration and with corresponding variations in wrist speed. Thus, cats reached for targets at different heights by scaling a common kinematic profile. Over a relatively large range of target heights, animals maintained movement duration constant, according to a simple "pulse-height" control strategy (isochronous scaling). For reaches to a given target height, animals compensated for variability in peak acceleration by variations in movement time. We examined the coordination between the shoulder and the wrist with the elbow. Early during the lift, peak shoulder extensor and peak elbow flexor accelerations were synchronized. Late during the lift phase, wrist extensor acceleration was found to occur during the period of elbow flexor deceleration. We hypothesize that these linkages could, in part, be due to passive mechanical interactions. To determine how the angular trajectories of the different joints were organized in relation to target location, we plotted joint kinematic changes directly on the wrist and MCP joint paths. These plots revealed that for all target heights and movement speeds, wrist extensor deceleration occurred at approximately the same spatial location with respect to the target. This analysis also demonstrated that the second phase of MCP flexion occurred when the paw was below the lower lip of the food well, while the subsequent extension occurred after the tip cleared this obstacle. During thrust, wrist and MCP angles were maintained, reflecting the need to align the paw within the food well. Our findings suggest that cats plan the reaching phase of prehension as a sequence of discrete movement segments, each serving a particular goal in the task, rather than as an single unit. PMID:7737385

Martin, J H; Cooper, S E; Ghez, C

1995-01-01

389

Pectoral fin locomotion in the striped surfperch. I. Kinematic effects of swimming speed and body size  

PubMed

Swimming trials at increasing velocity were used to determine the effects of steady swimming speed on pectoral fin kinematics for an ontogenetic series of striped surfperch Embiotoca lateralis, ranging from 6 to 23 cm in standard length (SL). The fin stroke cycle consisted of a propulsive period, the duration of fin abduction and adduction, and a 'refractory' period, during which the fin remained adducted against the body. Pectoral fin-beat frequency (fp) measured as the inverse of the entire stride period, as in past studies, increased curvilinearly with speed. Frequency, calculated as the reciprocal of the propulsive period alone, increased linearly with speed, as shown previously for tail-beat frequency of fishes employing axial undulation. Fin-beat amplitude, measured as the vertical excursion of the pectoral fin tip during abduction, increased over a limited range of low speeds before reaching a plateau at 0.35­0.40 SL. Pectoral fin locomotion was supplemented by intermittent caudal fin undulation as swimming speed increased. At the pectoral­caudal gait transition speed (Up-c), frequency and amplitude attained maxima, suggesting that the fin musculature reached a physiological limit. The effects of body size on swimming kinematics differed according to the method used for expressing speed. At a given absolute speed, small fish used higher stride frequencies and increased frequency at a faster rate than large fish. In contrast, the relationship between fp and length-specific speed (SL s-1) had a greater slope for large fish and crossed that for small fish at high speeds. We recommend that comparisons across size be made using speeds expressed as a percentage of Up-c, at which kinematic variables influencing thrust are size-independent. PMID:9320150

Drucker; Jensen

1996-01-01

390

Optimal Estimation of Dynamically Consistent Kinematics and Kinetics for Forward Dynamic Simulation of Gait  

PubMed Central

Background Forward dynamic simulation provides a powerful framework for characterizing in vivo loads, and for predicting changes in movement due to injury, impairment or surgical intervention. However, the computational challenge of generating simulations has greatly limited the use and application of forward dynamic models for simulating human gait. Methods In this study, we introduce an optimal estimation approach to effciently solve for generalized accelerations that satisfy the overall equations of motion and best agree with measured kinematics and ground reaction forces. The estimated accelerations are numerically integrated to enforce dynamic consistency over time, resulting in a forward dynamic simulation. Numerical optimization is then used to determine a set of initial generalized coordinates and speeds that produce a simulation that is most consistent with the measured motion over a full cycle of gait. The proposed method was evaluated with synthetically created kinematics and forceplate data in which both random noise and bias errors were introduced. We also applied the method to experimental gait data collected from five young healthy adults walking at a preferred speed. Results and Conclusions We show that the proposed residual elimination algorithm (REA) converges to an accurate solution, reduces the detrimental effects of kinematic measurement errors on joint moments, and eliminates the need for residual forces that arise in standard inverse dynamics. The greatest improvements in joint kinetics were observed proximally, with the algorithm reducing joint moment errors due to marker noise by over 20% at the hip and over 50% at the low back. Simulated joint angles were generally within 1 deg of recorded values when REA was used to generate a simulation from experimental gait data. REA can thus be used as a basis for generating accurate simulations of subject-specific gait dynamics.

Remy, Christian D.; Thelen, Darryl G.

2010-01-01

391

Visualization of dual-arm robot motion space under kinematic constraints  

SciTech Connect

This article presents a technique for determining and visualizing the geometric motion capabilities of dual-arm robotic systems when the arms work on an object in a closed kinematic chain configuration, taking account of robot arms' base placements, object dimensions, object holding and contact constraints, and space occupancy conflicts of the two arms' links. The constrained and object orientation restricted motion space in general can be visualized as a complex 3D object with hidden unreachable holes or cavities of varying shapes. An automated visualization methodology is presented together with its graphical implementation, illustrated by an example. The methodology is an inverse computer vision technique in the sense that it creates rather than recognizes visual forms. 18 refs., 5 figs.

Tarn, T.J. (Washington Univ., St. Louis, MO (United States)); De, P.K. (Lockwood Greene Engineers, Inc., Atlanta, GA (United States)); Bejczy, A.K. (Jet Propulsion Lab., Pasadena, CA (United States)); Li, Z. (Washington Univ. School of Medicine, St. Louis, MO (United States))

1995-02-01

392

Action Understanding as Inverse Planning  

ERIC Educational Resources Information Center

|Humans are adept at inferring the mental states underlying other agents' actions, such as goals, beliefs, desires, emotions and other thoughts. We propose a computational framework based on Bayesian inverse planning for modeling human action understanding. The framework represents an intuitive theory of intentional agents' behavior based on the…

Baker, Chris L.; Saxe, Rebecca; Tenenbaum, Joshua B.

2009-01-01

393

The double inverse polarity paradigm  

Microsoft Academic Search

A model is presented for the origin of inverse polarity magnetic fields in the perpendicular as well as in the axial direction of quiescent prominences. The model is based on the presence of a discrete coronal arcade structure where magnetic separating surfaces can be identified. On the crossing of these separating surfaces magnetic reconnection driven by photospheric shear and converging

Max Kuperus

1996-01-01

394

Action Understanding as Inverse Planning  

ERIC Educational Resources Information Center

Humans are adept at inferring the mental states underlying other agents' actions, such as goals, beliefs, desires, emotions and other thoughts. We propose a computational framework based on Bayesian inverse planning for modeling human action understanding. The framework represents an intuitive theory of intentional agents' behavior based on the…

Baker, Chris L.; Saxe, Rebecca; Tenenbaum, Joshua B.

2009-01-01

395

Action understanding as inverse planning  

Microsoft Academic Search

Humans are adept at inferring the mental states underlying other agents’ actions, such as goals, beliefs, desires, emotions and other thoughts. We propose a computational framework based on Bayesian inverse planning for modeling human action understanding. The framework represents an intuitive theory of intentional agents’ behavior based on the principle of rationality: the expectation that agents will plan approximately rationally

Chris L. Baker; Rebecca Saxe; Joshua B. Tenenbaum

2009-01-01

396

Inverse Operations in School Teaching.  

ERIC Educational Resources Information Center

The theory of unary and binary operations are discussed and illustrated with examples from school mathematics. Presentations of selected inverse operations are made and attention is drawn to certain "typical" problems that occur during instruction and learning of these concepts. (MP)

Bryll, Grzegorz; Rabijewska, Barbara

1980-01-01

397

Global convergence for Inverse Problems  

NASA Astrophysics Data System (ADS)

A globally convergent numerical method for a multidimensional Coefficient Inverse Problem for a hyperbolic equation is presented. It is shown that this technique provides a good starting point for the finite element adaptive method (adaptivity). This leads to a natural two-stage numerical procedure, which synthesizes both these methods.

Beilina, L.; Klibanov, M. V.

2010-09-01

398

Kinematic tests of exotic flat cosmological models  

SciTech Connect

Theoretical prejudice and inflationary models of the very early Universe strongly favor the flat, Einstein-deSitter model of the Universe. At present the observational data conflict with this prejudice. This conflict can be resolved by considering flat models of the Universe which possess a smooth component by energy density. We study in detail the kinematics of such models, where the smooth component is relativistic particles, a cosmological term, a network of light strings, or fast-moving, light strings. We also discuss the observational tests which can be used to discriminate between these models. These tests include the magnitude-redshift, lookback time-redshift, angular size-redshift, and comoving volume-redshift diagrams and the growth of density fluctuations.

Charlton, J.C.; Turner, M.S.

1986-05-01

399

Improved wave kinematics from wave staff arrays  

SciTech Connect

A method is described for improved prediction of wave kinematics from wave staff array records. This new procedure assigns directions, as well as amplitudes and phases, to wave components at each Fourier frequency, in such a way as to fit the wave staff records best. The water particle velocities from each wave component are added vectorially with various modifications to the basic linear superposition method of the type known as ''stretching.'' Using storm data from Exxon's Ocean Test Structure, predicted water particle velocities are compared with measured values at a number of current meters. Evaluations are made of the importance of modifications to the superposition procedure and of the use of multiple wave staff records and directionality.

Pawsey, S.F.; Dello Stritto, F.J.

1983-05-01

400

Adjustable link for kinematic mounting systems  

DOEpatents

An adjustable link for kinematic mounting systems. The adjustable link is a low-cost, passive device that provides backlash-free adjustment along its single constraint direction and flexural freedom in all other directions. The adjustable link comprises two spheres, two sockets in which the spheres are adjustable retain, and a connection link threadly connected at each end to the spheres, to provide a single direction of restraint and to adjust the length or distance between the sockets. Six such adjustable links provide for six degrees of freedom for mounting an instrument on a support. The adjustable link has applications in any machine or instrument requiring precision adjustment in six degrees of freedom, isolation from deformations of the supporting platform, and/or additional structural damping. The damping is accomplished by using a hollow connection link that contains an inner rod and a viscoelastic separation layer between the two.

Hale, Layton C. (Livermore, CA)

1997-01-01

401

Alcohol consumption and handwriting: a kinematic analysis.  

PubMed

Cerebellar dysfunction is associated with deficits in the control of movement extent, as well as changes in the amplitude and relative amounts of acceleration and deceleration and action tremor. The present study sought to identify whether cerebellar symptoms occur in the handwriting of intoxicated individuals. Twenty participants in two sub-groups (alcohol dependent and non-alcohol dependent) were asked to write four cursive letter 'l's on a Wacom SD420 graphics tablet before and after consumption of a dose of vodka and orange producing a peak blood alcohol concentration of 0.048%. There was a relationship between blood alcohol concentration and stroke length. Kinematic analysis of handwriting indicated increases in the relative proportions of time spent in acceleration and increases in spectral power around 4Hz. It was found that alcohol intoxication causes symptoms of cerebellar dysfunction, and that alcohol dependent individuals had less ballistic handwriting compared to non-alcohol dependent participants. PMID:19395108

Phillips, James G; Ogeil, Rowan P; Müller, Friedemann

2009-04-22

402

Robot Calibration Using Iteration and Differential Kinematics  

NASA Astrophysics Data System (ADS)

In the applications of seam laser tracking welding robot and general measuring robot station based on stereo vision, the robot calibration is the most difficult step during the whole system calibration progress. Many calibration methods were put forward, but the exact location of base frame has to be known no matter which method was employed. However, the accurate base frame location is hard to be known. In order to obtain the position of base coordinate, this paper presents a novel iterative algorithm which can also get parameters' deviations at the same time. It was a method of employing differential kinematics to solve link parameters' deviations and approaching real values step-by-step. In the end, experiment validation was provided.

Ye, S. H.; Wang, Y.; Ren, Y. J.; Li, D. K.

2006-10-01

403

Unraveling L_{n,k}: Grassmannian Kinematics  

SciTech Connect

It was recently proposed that the leading singularities of the S-Matrix of N = 4 super Yang-Mills theory arise as the residues of a contour integral over a Grassmannian manifold, with space-time locality encoded through residue theorems generalizing Cauchy's theorem to more than one variable. We provide a method to identify the residue corresponding to any leading singularity, and we carry this out explicitly for all leading singularities at tree level and one-loop. We also give several examples at higher loops, including all generic two-loop leading singularities and an interesting four-loop object. As an example we consider a 12-pt N{sup 4}MHV leading singularity at two loops that has a kinematic structure involving double square roots. Our analysis results in a simple picture for how the topological structure of loop graphs is reflected in various substructures within the Grassmannian.

Kaplan, Jared; /SLAC

2010-02-15

404

Uncertainty quantification in kinematic wave models  

SciTech Connect

We developed a probabilistic approach to quantify parametric uncertainty in first-order hyperbolic conservation laws (kinematic wave equations). The approach relies on the derivation of a deterministic equation for the cumulative density function (CDF) of the system state, in which probabilistic descriptions (probability density functions or PDFs) of the system parameters and/or initial and boundary conditions serve as inputs. In contrast to PDF equations, which are often used in other contexts, CDF equations allow for straightforward and unambiguous determination of boundary conditions with respect to sample variables.The accuracy and robustness of solutions of the CDF equation for one such system, the Saint-Venant equations of river flows, were investigated via comparison with Monte Carlo simulations.

Wang, Peng; Tartakovsky, Daniel M.

2012-10-01

405

Optimal control of reaching includes kinematic constraints.  

PubMed

We investigate adaptation under a reaching task with an acceleration-based force field perturbation designed to alter the nominal straight hand trajectory in a potentially benign manner: pushing the hand off course in one direction before subsequently restoring towards the target. In this particular task, an explicit strategy to reduce motor effort requires a distinct deviation from the nominal rectilinear hand trajectory. Rather, our results display a clear directional preference during learning, as subjects adapted perturbed curved trajectories towards their initial baselines. We model this behavior using the framework of stochastic optimal control theory and an objective function that trades off the discordant requirements of 1) target accuracy, 2) motor effort, and 3) kinematic invariance. Our work addresses the underlying objective of a reaching movement, and we suggest that robustness, particularly against internal model uncertainly, is as essential to the reaching task as terminal accuracy and energy efficiency. PMID:23554437

Mistry, Michael; Theodorou, Evangelos; Schaal, Stefan; Kawato, Mitsuo

2013-04-03

406

Probing dark matter haloes with satellite kinematics  

NASA Astrophysics Data System (ADS)

Using detailed mock galaxy redshift surveys (MGRSs) we investigate to what extent the kinematics of large samples of satellite galaxies extracted from flux-limited surveys can be used to constrain halo masses. Unlike previous studies, which focused only on satellites around relatively isolated host galaxies, we try to recover the average velocity dispersion of satellite galaxies in all haloes, as a function of the luminosity of the host galaxy. We show that previous host-satellite selection criteria (SC) yield relatively large fractions of interlopers and with a velocity distribution that, contrary to what has been assumed in the past, differs strongly from uniform. We show that with an iterative, adaptive selection criterion one can obtain large samples of hosts and satellites, with strongly reduced interloper fractions, that allow an accurate measurement of ?sat(Lhost) over 2.5 orders of magnitude in host luminosity. We use the conditional luminosity function (CLF) to make predictions and show that satellite weighting, which occurs naturally when stacking many host-satellite pairs to increase the signal-to-noise ratio, introduces a bias towards higher ?sat(Lhost) compared to the true, host-averaged mean. A further bias, in the same direction, is introduced when using flux-limited, rather than volume-limited, surveys. We apply our adaptive selection criterion to the Two Degree Field Galaxy Redshift Survey (2dFGRS) and obtain a sample of 12569 satellite galaxies and 8132 host galaxies. We show that the kinematics of these satellite galaxies are in excellent agreement with the predictions based on the CLF, after taking account of the various biases. We thus conclude that there is independent dynamical evidence to support the mass-to-light ratios predicted by the CLF formalism.

van den Bosch, Frank C.; Norberg, Peder; Mo, H. J.; Yang, Xiaohu

2004-08-01

407

Galactic kinematics from YSOs sample (Bobylev+, 2013)  

NASA Astrophysics Data System (ADS)

Based on published sources, we have created a kinematic database on 220 massive (>10M?) young Galactic star systems located within <3 kpcof the Sun. Out of them, approximately 100 objects are spectroscopic binary and multiple star systems whose components are massive OB stars; the remaining objects are massive Hipparcos B stars with parallax errors of no more than 10 percent. Based on the entire sample, we have constructed the Galactic rotation curve, determined the circular rotation velocity of the solar neighborhood around the Galactic center R0=8kpc, V0=259+/-16km/s, and obtained the following spiral density wave parameters: the amplitudes of the radial and azimuthal velocity perturbations fR=-10.8+/-1.2km/s, and f?=7.9+/-1.3km/s, respectively; the pitch angle for a two-armed spiral pattern i=-6.0+/-0.4deg, with the wavelength of the spiral density wave near the Sun being ?=2.6+/-0.2kpc; and the radial phase of the Sun in the spiral density wave {chi}?=-120+/-4°. We show that such peculiarities of the Gould Belt as the local expansion of the system, the velocity ellipsoid vertex deviation, and the significant additional rotation can be explained in terms of the density wave theory. All these effects decrease noticeably once the influence of the spiral density wave on the velocities of nearby stars has been taken into account. The influence of Gould Belt stars on the Galactic parameter estimates has also been revealed. Eliminating them from the kinematic equations has led to the following new values of the spiral density wave parameters: f?=2.9+/-2.1km/s and {chi}?=-104+/-6°. (2 data files).

Bobylev, V. V.; Bajkova, A. T.

2013-10-01

408

Kinematics of stellar populations with RAVE data  

NASA Astrophysics Data System (ADS)

We study the kinematics of the Galactic thin and thick disk populations using stars from the RAVE survey's second data release together with distance estimates from Breddels et al. (2010). The velocity distribution exhibits the expected moving groups present in the solar neighborhood. We separate thick and thin disk stars by applying the X (stellar-population) criterion of Schuster et al. (1993), which takes into account both kinematic and metallicity information. For 1906 thin disk and 110 thick disk stars classified in this way, we find a vertical velocity dispersion, mean rotational velocity and mean orbital eccentricity of ( ?W, < V?>, < e>) thin = (18 ± 0.3 km s -1, 223 ± 0.4 km s -1, 0.07 ± 0.07) and ( ?W, < V?>, < e>) thick = (35 ± 2 km s -1, 163 ± 3 km s -1, 0.31 ± 0.16), respectively. From the radial Jeans equation, we derive a thick disk scale length in the range 1.5-2.2 kpc, whose greatest uncertainty lies in the adopted form of the underlying potential. The shape of the orbital eccentricity distribution indicates that the thick disk stars in our sample most likely formed in situ with minor gas-rich mergers and/or radial migration being the most likely cause for their orbits. We further obtain mean metal abundances of <[M/H]> thin = +0.03 ± 0.17, and <[M/H]> thick = -0.51 ± 0.23, in good agreement with previous estimates. We estimate a radial metallicity gradient in the thin disk of -0.07 dex kpc -1, which is larger than predicted by chemical evolution models where the disk grows inside-out from infalling gas. It is, however, consistent with models where significant migration of stars shapes the chemical signature of the disk, implying that radial migration might play at least part of a role in the thick disk's formation.

Karata?, Yüksel; Klement, Rainer J.

2012-01-01

409

Medial compressible forefoot sole elements reduce ankle inversion in lateral SSC jumps.  

PubMed

Sideward movements are associated with high incidences of lateral ankle sprains. Special shoe constructions might be able to reduce these injuries during lateral movements. The purpose of this study was to investigate whether medial compressible forefoot sole elements can reduce ankle inversion in a reactive lateral movement, and to evaluate those elements' influence on neuromuscular and mechanical adjustments in lower extremities. Foot placement and frontal plane ankle joint kinematics and kinetics were analyzed by 3-dimensional motion analysis. Electromyographic data of triceps surae, peroneus longus, and tibialis anterior were collected. This modified shoe reduced ankle inversion in comparison with a shoe with a standard sole construction. No differences in ankle inversion moments were found. With the modified shoe, foot placement occurred more internally rotated, and muscle activity of the lateral shank muscles was reduced. Hence, lateral ankle joint stability during reactive sideward movements can be improved by these compressible elements, and therefore lower lateral shank muscle activity is required. As those elements limit inversion, the strategy to control inversion angles via a high external foot rotation does not need to be used. PMID:22923308

Fleischmann, Jana; Mornieux, Guillaume; Gehring, Dominic; Gollhofer, Albert

2012-08-22

410

The Double-Ring Algorithm: A Tool for Assimilating Active Region Data Directly into Kinematic Dynamo Models  

NASA Astrophysics Data System (ADS)

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 ?-effect in kinematic mean-field dynamo models. However, not only 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, but also makes it very difficult to assimilate active region data into kinematic dynamo models. 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. We demonstrate that our treatment of the Babcock-Leighton mechanism through double-ring eruption leads to an inverse relationship between polar field strength and meridional flow speed as expected, reconciling the discrepancy between surface flux-transport simulations and kinematic dynamo models. Finally, we show how this new formulation paves the way for applications, which were not possible before, like the direct assimilation of active region data.

Munoz-Jaramillo, A.; Nandi, D.; Martens, P. C.; Yeates, A. R.

2011-12-01

411

A DOUBLE-RING ALGORITHM FOR MODELING SOLAR ACTIVE REGIONS: UNIFYING KINEMATIC DYNAMO MODELS AND SURFACE FLUX-TRANSPORT SIMULATIONS  

SciTech Connect

The emergence of tilted bipolar active regions (ARs) 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 AR 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 dynamics. Finally, we demonstrate that our treatment of the Babcock-Leighton mechanism through double-ring eruption leads to an inverse relationship between polar field strength and meridional flow speed as expected, reconciling the discrepancy between surface flux-transport simulations and kinematic dynamo models.

Munoz-Jaramillo, Andres; Martens, Petrus C. H. [Department of Physics, Montana State University, Bozeman, MT 59717 (United States); Nandy, Dibyendu [Department of Physical Sciences, Indian Institute for Science Education and Research, Kolkata, Mohampur 741 252, West Bengal (India); Yeates, Anthony R., E-mail: munoz@solar.physics.montana.ed, E-mail: dnandi@iiserkol.ac.i, E-mail: martens@solar.physics.montana.ed, E-mail: anthony@maths.dundee.ac.u [Division of Mathematics, University of Dundee, Dundee DD1 4HN, Scotland (United Kingdom)

2010-09-01

412

Anaerobic digestion of dairy wastewater by inverse fluidization: The inverse fluidized bed and the inverse turbulent bed reactors  

Microsoft Academic Search

This paper describes the application of the inverse fluidization technology to the anaerobic digestion of dairy wastewater. Two reactors were investigated: the inverse fluidized bed reactor and the inverse turbulent reactor. In these reactors, a granular floating solid is expanded by a down?flow current of effluent or an up?flow current of gas, respectively. The carrier particles (Extendospheres) were chosen for

C. Arnaiz; P. Buffiere; S. Elmaleh; J. Lebrato; R. Moletta

2003-01-01

413

Graphical Representations of Kinematical Concepts: A Comparison of Teaching Strategies  

NASA Astrophysics Data System (ADS)

Student difficulties with kinematics concepts and their representations by linear graphs are well known. Several specific learning difficulties have been identified and reported, mainly from studies at the introductory university physics level.1-4 In this paper we investigate the effectiveness of active learning strategies versus traditional instruction on the development of student understanding of kinematical concepts, and their graphical representations, by high school students. We also examine the retention of acquired kinematic concepts and whether it might be affected by subsequent (traditional) instruction.

Guidugli, Silvina; Gauna, Cecilia Fernández; Benegas, Julio

2005-09-01

414

Inverse statistics and information content  

NASA Astrophysics Data System (ADS)

Inverse statistics analysis studies the distribution of investment horizons to achieve a predefined level of return. This distribution provides a maximum investment horizon which determines the most likely horizon for gaining a specific return. There exists a significant difference between inverse statistics of financial market data and a fractional Brownian motion (fBm) as an uncorrelated time-series, which is a suitable criteria to measure information content in financial data. In this paper we perform this analysis for the DJIA and S&P500 as two developed markets and Tehran price index (TEPIX) as an emerging market. We also compare these probability distributions with fBm probability, to detect when the behavior of the stocks are the same as fBm.

Ebadi, H.; Bolgorian, Meysam; Jafari, G. R.

2010-12-01

415

Broadband synthetic aperture geoacoustic inversion.  

PubMed

A typical geoacoustic inversion procedure involves powerful source transmissions received on a large-aperture receiver array. A more practical approach is to use a single moving source and/or receiver in a low signal to noise ratio (SNR) setting. This paper uses single-receiver, broadband, frequency coherent matched-field inversion and exploits coherently repeated transmissions to improve estimation of the geoacoustic parameters. The long observation time creates a synthetic aperture due to relative source-receiver motion. This approach is illustrated by studying the transmission of multiple linear frequency modulated (LFM) pulses which results in a multi-tonal comb spectrum that is Doppler sensitive. To correlate well with the measured field across a receiver trajectory and to incorporate transmission from a source trajectory, waveguide Doppler and normal mode theory is applied. The method is demonstrated with low SNR, 100-900?Hz LFM pulse data from the Shallow Water 2006 experiment. PMID:23862809

Tan, Bien Aik; Gerstoft, Peter; Yardim, Caglar; Hodgkiss, William S

2013-07-01

416

Resolution of iterative inverses in seismic tomography  

NASA Astrophysics Data System (ADS)

With applications to seismic travel time tomography in mind, methods have been developed for computing both the model and data resolution matrices for iterative inverse such as those produced by the Lanczos scheme for finding a matrix inverse.

Berryman, J. G.

1994-02-01

417

Adaptive Non-Linear Inversion Algorithms.  

National Technical Information Service (NTIS)

Computationally efficient inversion algorithms are needed in a variety of disciplines, such as medical imaging, nondestructive evaluation, geophysical prospecting, and robotic vision. The rigorous mathematical models of inversion that are associated with ...

L. D. Sabbagh S. Barkeshli H. A. Sabbagh

1990-01-01

418

Pyramidal inversion domain boundaries revisited  

SciTech Connect

The structure of pyramidal inversion domain boundaries in GaN:Mg was investigated by aberration corrected transmission electron microscopy. The analysis shows the upper (0001) boundary to consist of a single Mg layer inserted between polarity inverted GaN layers in an abcab stacking. The Mg bound in these defects is at least one order of magnitude lower than the chemical Mg concentration. Temperature dependent Hall effect measurements show that up to 27% of the Mg acceptors is electrically compensated.

Remmele, T.; Albrecht, M.; Irmscher, K.; Fornari, R. [Leibniz-Institut fuer Kristallzuechtung, Max-Born-Str. 2, 12489 Berlin (Germany); Strassburg, M. [OSRAM Optical Semiconductors GmbH, Leibniz Strasse 4, 93055 Regensburg (Germany)

2011-10-03

419

Kinematic Seismic Rupture Parameters from a Doppler Analysis  

NASA Astrophysics Data System (ADS)

The radiation emitted from extended seismic sources, mainly when the rupture spreads in preferred directions, presents spectral deviations as a function of the observation location. This aspect, unobserved to point sources, and named as directivity, are manifested by an increase in the frequency and amplitude of seismic waves when the rupture occurs in the direction of the seismic station and a decrease in the frequency and amplitude if it occurs in the opposite direction. The model of directivity that supports the method is a Doppler analysis based on a kinematic source model of rupture and wave propagation through a structural medium with spherical symmetry [1]. A unilateral rupture can be viewed as a sequence of shocks produced along certain paths on the fault. According this model, the seismic record at any point on the Earth's surface contains a signature of the rupture process that originated the recorded waveform. Calculating the rupture direction and velocity by a general Doppler equation, - the goal of this work - using a dataset of common time-delays read from waveforms recorded at different distances around the epicenter, requires the normalization of measures to a standard value of slowness. This normalization involves a non-linear inversion that we solve numerically using an iterative least-squares approach. The evaluation of the performance of this technique was done through a set of synthetic and real applications. We present the application of the method at four real case studies, the following earthquakes: Arequipa, Peru (Mw = 8.4, June 23, 2001); Denali, AK, USA (Mw = 7.8; November 3, 2002); Zemmouri-Boumerdes, Algeria (Mw = 6.8, May 21, 2003); and Sumatra, Indonesia (Mw = 9.3, December 26, 2004). The results obtained from the dataset of the four earthquakes agreed, in general, with the values presented by other authors using different methods and data. [1] Caldeira B., Bezzeghoud M, Borges JF, 2009; DIRDOP: a directivity approach to determining the seismic rupture velocity vector. J Seismology, DOI 10.1007/s10950-009-9183-x

Caldeira, Bento; Bezzeghoud, Mourad; Borges, José F.

2010-05-01

420

Onset of collectivity in neutron-rich Fe isotopes: Toward a new island of inversion?  

SciTech Connect

The lifetimes of the first excited 2{sup +} states in {sup 62}Fe and {sup 64}Fe have been measured for the first time using the recoil-distance Doppler shift method after multinucleon transfer reactions in inverse kinematics. A sudden increase of collectivity from {sup 62}Fe to {sup 64}Fe is observed. The experimental results are compared with new large-scale shell-model calculations and Hartree-Fock-Bogolyubov-based configuration-mixing calculations using the Gogny D1S interaction. The results give a deeper understanding of the mechanism leading to an onset of collectivity near {sup 68}Ni, which is compared with the situation in the so-called island of inversion around {sup 32}Mg.

Ljungvall, J. [CEA Saclay, IRFU, Service de Physique Nucleaire, F-91191 Gif-sur-Yvette (France); GANIL, CEA/DSM-CNRS/IN2P3, Bd Henri Becquerel, BP 55027, F-14076 Caen (France); CSNSM, CNRS/IN2P3, F-91405 Orsay (France); Goergen, A.; Obertelli, A.; Korten, W. [CEA Saclay, IRFU, Service de Physique Nucleaire, F-91191 Gif-sur-Yvette (France); Clement, E.; France, G. de; Rejmund, M.; Schmitt, C.; Shrivastava, A. [GANIL, CEA/DSM-CNRS/IN2P3, Bd Henri Becquerel, BP 55027, F-14076 Caen (France); Buerger, A. [Department of Physics, University of Oslo, PO Box 1048 Blindern, N-0316 Oslo (Norway); Delaroche, J.-P.; Gaudefroy, L.; Girod, M. [CEA, DAM, DIF, F-91297 Arpajon (France); Dewald, A.; Hackstein, M.; Pissulla, T.; Rother, W.; Zell, K. O. [Institut fuer Kernphysik, Universitaet zu Koeln, D-50937 Koeln (Germany); Gadea, A. [Instituto de Fisica Corpuscular, CSIC-Universidad de Valencia, E-46071 Valencia (Spain); Libert, J. [Institut de Physique Nucleaire, CNRS/IN2P3-Universite Paris-Sud, F-91406 Orsay (France)

2010-06-15

421

Spatial distribution and kinematics of OB stars  

NASA Astrophysics Data System (ADS)

The sample of 37 485 suspected OB stars selected by Gontcharov (2008) from the Tycho-2 catalogue has been cleaned of the stars that are not of spectral types OV-A0V. For this purpose, the apparent magnitude V T from Tycho-2, the absolute magnitude M_{V_T } calibrated as a function of the dereddened color index ( B T - V T )0, the interstellar extinction A_{V_T } calculated from the 3D analytical model by Gontcharov (2009) as a function of the Galactic coordinates, and the photometric distance r ph calculated as a function of V T , M_{V_T }, and A_{V_T } have been reconciled in an iterative process. The 20 514 stars that passed the iterations have ( B T - V T )0 < 0 and M_{V_T } > -5 and are considered as a sample of OV-A0V stars complete within 350 pc of the Sun. Based on the theoretical relation between the dereddened color and age of the stars, the derived sample has been divided into three subsamples: ( B T - V T )0 < -0.2, -0.2 < ( B T - V T )0 < -0.1, and -0.1 < ( B T - V T )0 < 0, younger than 100, 100-200, and 200-400 Myr, respectively. The spatial distribution of all 20 514 stars and the kinematics analyzed for more than 1500 stars with radial velocities from the PCRV and RAVE catalogues are different for the subsamples, showing smooth rotations, shears, and deformations of the layer of gas producing stars with the formation of the Gould Belt, the Great Tunnel, the Local Bubble, and other structures within the last 200 Myr. The detected temporal variations of the velocity dispersions, solar motion components, Ogorodnikov-Milne model parameters, and Oort constants are significant, agree with the results of other authors, and show that it is meaningless to calculate the kinematic parameters for samples of stars with uncertain ages or with a wide range of ages.

Gontcharov, G. A.

2012-11-01

422

On Some Inverse Methods in Electromagnetics  

Microsoft Academic Search

The purpose of this paper is to review some of the inverse methods in electromagnetics for the reconstruction of one-dimensional permittivity and conductivity profiles using transient or spectral data. Two different categories of inversion schemes, viz., the differential-inverse and integral-inverse algorithms, are discussed, and their relationships to other approaches developed in the fields of quantum mechanics and geophysics are pointed

T. M. Habashy; R. Mittra

1987-01-01

423

Hybrid methods for inverse aerodynamic design  

Microsoft Academic Search

This thesis describes a novel hybrid approach for the multipoint inverse design of airfoils for complex aerodynamic systems. In this approach, an inverse design method for single-element airfoils is coupled with an analysis module for the complex system. The airfoils that comprise the complex system are generated in isolation using the single-element airfoil inverse design method. The analysis module is

Ashok Gopalarathnam

1999-01-01

424

BOOK REVIEW: Inverse Problems. Activities for Undergraduates  

Microsoft Academic Search

This book is a valuable introduction to inverse problems. In particular, from the educational point of view, the author addresses the questions of what constitutes an inverse problem and how and why we should study them. Such an approach has been eagerly awaited for a long time. Professor Groetsch, of the University of Cincinnati, is a world-renowned specialist in inverse

Charles W. Groetsch

2003-01-01

425

Inversion of azimuthally dependent NMO velocity in transversely isotropic media with a tilted axis of symmetry  

SciTech Connect

Just as the transversely isotropic model with a vertical symmetry axis (VTI media) is typical for describing horizontally layered sediments, transverse isotropy with a tilted symmetry axis (TTI) describes dipping TI layers (such as tilted shale beds near salt domes) or crack systems. P-wave kinematic signatures in TTI media are controlled by the velocity V{sub PO} in the symmetry direction, Thomsen's anisotropic coefficients {xi} and {delta}, and the orientation (tilt {nu} and azimuth {beta}) of the symmetry axis. Here, the authors show that all five parameters can be obtained from azimuthally varying P-wave NMO velocities measured for two reflectors with different dips and/or azimuths (one of the reflectors can be horizontal). The shear-wave velocity V{sub SO} in the symmetry direction, which has negligible influence on P-wave kinematic signatures, can be found only from the moveout of shear waves. Using the exact NMO equation, the authors examine the propagation of errors in observed moveout velocities into estimated values of the anisotropic parameters and establish the necessary conditions for a stable inversion procedure. Since the azimuthal variation of the NMO velocity is elliptical, each reflection event provides them with up to three constraints on the model parameters. Generally, the five parameters responsible for P-wave velocity can be obtained from two P-wave ellipses, but the feasibility of the moveout inversion strongly depends on the tilt {nu}. While most of the analysis is carried out for a single layer, the authors also extend the inversion algorithm to vertically heterogeneous TTI media above a dipping reflector using the generalized Dix equation. A synthetic example for a strongly anisotropic, stratified TTI medium demonstrates a high accuracy of the inversion.

Grechka, V.; Tsvankin, I.

2000-02-01

426

Differences in normal and perturbed walking kinematics between male and female athletes  

Microsoft Academic Search

Objective. To identify differences in lower extremity kinematic movement patterns between genders during walking through the application of an expected perturbation.Design. Randomized limb kinematics were compared between healthy active males and females.Background. Lower extremity kinematics during jump landing and cutting have been implicated as a potential source of the discrepancy in anterior cruciate ligament injury rates between genders. Kinematic differences

Wendy J. Hurd; Terese L. Chmielewski; Michael J. Axe; Irene Davis; Lynn Snyder-Mackler

2004-01-01

427

STAR CLUSTERS IN M31: OLD CLUSTERS WITH BAR KINEMATICS  

SciTech Connect

We analyze our accurate kinematical data for the old clusters in the inner regions of M31. These velocities are based on high signal-to-noise Hectospec data. The data are well suited for analysis of M31's inner regions because we took particular care to correct for contamination by unresolved field stars from the disk and bulge in the fibers. The metal-poor clusters show kinematics that are compatible with a pressure-supported spheroid. The kinematics of metal-rich clusters, however, argue for a disk population. In particular the innermost region (inside 2 kpc) shows the kinematics of the x{sub 2} family of bar periodic orbits, arguing for the existence of an inner Lindblad resonance in M31.

Morrison, Heather; Harding, Paul [Department of Astronomy, Case Western Reserve University, Cleveland, OH 44106-7215 (United States); Caldwell, Nelson [Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Schiavon, Ricardo P. [Gemini Observatory, 670 N. A'ohoku Place, Hilo, HI 96720 (United States); Athanassoula, E. [LAM/OAMP, UMR6110, CNRS/Univ. de Provence, 38 rue Joliot Curie, 13388 Marseille 13 (France); Romanowsky, Aaron J., E-mail: heather@vegemite.case.edu, E-mail: paul.harding@case.edu, E-mail: caldwell@cfa.harvard.edu, E-mail: rschiavo@gemini.edu, E-mail: lia@oamp.fr, E-mail: romanow@ucolick.org [UCO/Lick Observatory, University of California, Santa Cruz, CA 95064 (United States)

2011-01-01

428

In vivo kinematic analysis of squatting after total hip arthroplasty  

Microsoft Academic Search

BackgroundThe in vivo kinematics of squatting after total hip arthroplasty is unclear. The purpose of the present study was to determine the range of motion of the hip joint during squatting after total hip arthroplasty.

Junichiro Koyanagi; Takashi Sakai; Takaharu Yamazaki; Tetsu Watanabe; Keisuke Akiyama; Nobuhiko Sugano; Hideki Yoshikawa; Kazuomi Sugamoto

2011-01-01

429

Kinematic cues and recognition of self-generated actions.  

PubMed

In the present study, we addressed the issue of whether healthy individuals can recognize a given gesture as their own, based on kinematic information. To this purpose, we required 36 volunteers to execute a series of hand movements of increasing complexity, while their kinematics was recorded by a motion-capture system. In a later session, we showed them a series of computer animations where a virtual hand, rendered as a simple stick-diagram, was animated by the kinematics recorded from the participants in the previous session. Their task was to recognize their own movements, choosing from three alternatives. To test the contribution of various potential cues to action recognition, the roles of (1) access to motor representation, (2) gesture complexity, and (3) familiarity effects were separately investigated. The results support the hypothesis that kinematic templates rather than single motor parameters contribute to self-recognition in the absence of morphological cues. PMID:16924486

Daprati, Elena; Wriessnegger, Selina; Lacquaniti, Francesco

2006-08-22

430

FPGA Processor Implementation for the Forward Kinematics of the UMDH.  

National Technical Information Service (NTIS)

The focus of this research was on the implementation of a forward kinematic algorithm for the Utah MIT Dexterous Hand (UMDH). Specifically, the algorithm was synthesized from mathematical models onto a Field Programmable Gate Array (FPGA) processor. The c...

S. M. Parmley

1997-01-01

431

Kinematic Structure of Helicity Amplitudes for Massless Particles.  

National Technical Information Service (NTIS)

A study is made of the kinematic structure of helicity amplitudes describing scattering with massless particles of arbitrary helicities, using certain basic analyticity assumptions on the M functions. The behaviors of the amplitudes at the thresholds and ...

L. N. Chang Y. C. Leung

1969-01-01

432

Fault Tolerant Kinematic Control of Hyper-Redundant Manipulators.  

National Technical Information Service (NTIS)

Hyper-redundant spatial manipulators possess fault-tolerant features because of their redundant structure. The kinematic control of these manipulators is investigated with special emphasis on fault-tolerant control. The manipulator tasks are viewed in the...

N. S. Bedrossian

1994-01-01

433

Geometric, Kinematic and Radiometric Aspects of Image-Based Measurements.  

National Technical Information Service (NTIS)

This paper discusses theoretical foundations of quantitative image-based measurements for extracting and reconstructing geometric, kinematic and dynamic properties of observed objects. New results are obtained by using a combination of methods in perspect...

T. Liu

2002-01-01

434

Kinematical and Chemical Vertical Structure of the Galactic Thick Disk. I. Thick Disk Kinematics  

NASA Astrophysics Data System (ADS)

The variation of the kinematical properties of the Galactic thick disk with Galactic height Z is studied by means of 412 red giants observed in the direction of the south Galactic pole up to 4.5 kpc from the plane. We confirm the non-null mean radial motion toward the Galactic anticenter found by other authors, but we find that it changes sign at |Z| = 3 kpc, and the proposed inward motion of the local standard of rest alone cannot explain these observations. The rotational velocity decreases with |Z| by -30 km s-1 kpc-1, but the data are better represented by a power law with index 1.25, similar to that proposed from the analysis of Sloan Digital Sky Survey data. All the velocity dispersions increase with |Z|, but the vertical gradients are small. The dispersions grow proportionally, with no significant variation of the anisotropy. The ratio ?U/?W = 2 suggests that the thick disk could have formed from a low-latitude merging event. The vertex deviation increases with Galactic height, reaching ~20° at |Z| = 3.5 kpc. The tilt angle also increases, and the orientation of the ellipsoid in the radial-vertical plane is constantly intermediate between the alignment with the cylindrical and the spherical coordinate systems. The tilt angle at |Z| = 2 kpc coincides with the expectations of MOdified Newtonian Dynamics, but an extension of the calculations to higher |Z| is required to perform a conclusive test. Finally, between 2.5 and 3.5 kpc we detect deviations from the linear trend of many kinematical quantities, suggesting that some kinematical substructure could be present. Based on observations collected at the European Organization for Astronomical Research in the Southern Hemisphere, Chile (proposal IDs 075.B-0459(A), 077.B-0348(A)). This paper includes data gathered with the 6.5 m Magellan and the duPont Telescopes, located at Las Campanas Observatory, Chile.

Moni Bidin, C.; Carraro, G.; Méndez, R. A.

2012-03-01

435

KINEMATICAL AND CHEMICAL VERTICAL STRUCTURE OF THE GALACTIC THICK DISK. I. THICK DISK KINEMATICS ,  

SciTech Connect

The variation of the kinematical properties of the Galactic thick disk with Galactic height Z is studied by means of 412 red giants observed in the direction of the south Galactic pole up to 4.5 kpc from the plane. We confirm the non-null mean radial motion toward the Galactic anticenter found by other authors, but we find that it changes sign at |Z| = 3 kpc, and the proposed inward motion of the local standard of rest alone cannot explain these observations. The rotational velocity decreases with |Z| by -30 km s{sup -1} kpc{sup -1}, but the data are better represented by a power law with index 1.25, similar to that proposed from the analysis of Sloan Digital Sky Survey data. All the velocity dispersions increase with |Z|, but the vertical gradients are small. The dispersions grow proportionally, with no significant variation of the anisotropy. The ratio {sigma}{sub U}/{sigma}{sub W} = 2 suggests that the thick disk could have formed from a low-latitude merging event. The vertex deviation increases with Galactic height, reaching {approx}20 Degree-Sign at |Z| = 3.5 kpc. The tilt angle also increases, and the orientation of the ellipsoid in the radial-vertical plane is constantly intermediate between the alignment with the cylindrical and the spherical coordinate systems. The tilt angle at |Z| = 2 kpc coincides with the expectations of MOdified Newtonian Dynamics, but an extension of the calculations to higher |Z| is required to perform a conclusive test. Finally, between 2.5 and 3.5 kpc we detect deviations from the linear trend of many kinematical quantities, suggesting that some kinematical substructure could be present.

Moni Bidin, C. [Departamento de Astronomia, Universidad de Concepcion, Casilla 160-C, Concepcion (Chile); Carraro, G. [European Southern Observatory, Alonso de Cordova 3107, Vitacura, Santiago (Chile); Mendez, R. A., E-mail: cmbidin@astro-udec.cl [Departamento de Astronomia, Universidad de Chile, Casilla 36-D, Santiago (Chile)

2012-03-10

436

Kinematics of AGN and Quasar Jets  

NASA Astrophysics Data System (ADS)

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 study the fine scale structure of the jet base.

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

2009-08-01

437

Growth rate degeneracies in kinematic dynamos  

NASA Astrophysics Data System (ADS)

We consider the classical problem of kinematic dynamo action in simple steady flows. Due to the adjointness of the induction operator, we show that the growth rate of the dynamo will be exactly the same for two types of magnetic boundary conditions: the magnetic field can be normal (infinite magnetic permeability, also called pseudovacuum) or tangent (perfect electrical conductor) to the boundaries of the domain. These boundary conditions correspond to well-defined physical limits often used in numerical models and relevant to laboratory experiments. The only constraint is for the velocity field u to be reversible, meaning there exists a transformation changing u into -u. We illustrate this surprising property using S2T2 type of flows in spherical geometry inspired by [Dudley and James, Proc. R. Soc. London A1364-502110.1098/rspa.1989.0112 425, 407 (1989)]. Using both types of boundary conditions, it is shown that the growth rates of the dynamos are identical, although the corresponding magnetic eigenmodes are drastically different.

Favier, B.; Proctor, M. R. E.

2013-09-01

438

On the Kinematics of Undulator Girder Motion  

SciTech Connect

The theory of rigid body kinematics is used to derive equations that govern the control and measurement of the position and orientation of undulator girders. The equations form the basis of the girder matlab software on the LCLS control system. The equations are linear for small motion and easily inverted as desired. For reference, some relevant girder geometrical data is also given. Equations 6-8 relate the linear potentiometer readings to the motion of the girder. Equations 9-11 relate the cam shaft angles to the motion of the girder. Both sets are easily inverted to either obtain the girder motion from the angles or readings, or, to find the angles and readings that would give a desired motion. The motion of any point on the girder can be calculated by applying either sets of equations to the two cam-planes and extrapolating in the z coordinate using equation 19. The formulation of the equations is quite general and easily coded via matrix and vector methods. They form the basis of the girder matlab software on the LCLS control system.

Welch, J

2011-08-18

439

Virtual human hand: model and kinematics.  

PubMed

The human hand plays an important role in daily life. It is the interface between the human and the exterior world by positioning, orienting, touching and grasping objects. The human hand has multiple degrees of freedom (DOFs) to enable mobility and dexterity. A virtual human hand model can be inserted into CAD (Computer Aided Design) models to assess the manipulation capabilities in the early design stage to reduce design time and cost. Joystick assessment is one of the important design cases. This study is a first step towards a comprehensive hand simulation tool to simulate the manipulation and grasping of objects. This paper presents a novel 25 DOFs' hand skeletal model based on hand anatomy and hand kinematics: (1) joint range of motion, (2) Denavit-Hartenberg method to define the joint relationship and (3) finger workspace determination. Novelty for this hand model includes arching the palm with the four DOFs added in the carpometacarpal and wrist joints for the ring and small fingers. PMID:22920244

Peña-Pitarch, Esteban; Falguera, Neus Ticó; Yang, Jingzhou James

2012-08-24

440

Kinematic mental simulations in abduction and deduction.  

PubMed

We present a theory, and its computer implementation, of how mental simulations underlie the abductions of informal algorithms and deductions from these algorithms. Three experiments tested the theory's predictions, using an environment of a single railway track and a siding. This environment is akin to a universal Turing machine, but it is simple enough for nonprogrammers to use. Participants solved problems that required use of the siding to rearrange the order of cars in a train (experiment 1). Participants abduced and described in their own words algorithms that solved such problems for trains of any length, and, as the use of simulation predicts, they favored "while-loops" over "for-loops" in their descriptions (experiment 2). Given descriptions of loops of procedures, participants deduced the consequences for given trains of six cars, doing so without access to the railway environment (experiment 3). As the theory predicts, difficulty in rearranging trains depends on the numbers of moves and cars to be moved, whereas in formulating an algorithm and deducing its consequences, it depends on the Kolmogorov complexity of the algorithm. Overall, the results corroborated the use of a kinematic mental model in creating and testing informal algorithms and showed that individuals differ reliably in the ability to carry out these tasks. PMID:24082090

Khemlani, Sangeet Suresh; Mackiewicz, Robert; Bucciarelli, Monica; Johnson-Laird, Philip N

2013-09-30

441

Learning Kinematic Constraints in Laparoscopic Surgery  

PubMed Central

To better understand how kinematic variables impact learning in surgical training, we devised an interactive environment for simulated laparoscopic maneuvers, using either 1) mechanical constraints typical of a surgical “box-trainer” or 2) virtual constraints in which free hand movements control virtual tool motion. During training, the virtual tool responded to the absolute position in space (Position-Based) or the orientation (Orientation-Based) of a hand-held sensor. Volunteers were further assigned to different sequences of target distances (Near-Far-Near or Far-Near-Far). Training with the Orientation-Based constraint enabled much lower path error and shorter movement times during training, which suggests that tool motion that simply mirrors joint motion is easier to learn. When evaluated in physically constrained (physical box-trainer) conditions, each group exhibited improved performance from training. However, Position-Based training enabled greater reductions in movement error relative to Orientation-Based (mean difference: 14.0 percent; CI: 0.7, 28.6). Furthermore, the Near-Far-Near schedule allowed a greater decrease in task time relative to the Far-Near-Far sequence (mean ?13:5 percent, CI: ?19:5, ?7:5). Training that focused on shallow tool insertion (near targets) might promote more efficient movement strategies by emphasizing the curvature of tool motion. In addition, our findings suggest that an understanding of absolute tool position is critical to coping with mechanical interactions between the tool and trocar.

Huang, Felix C.; Mussa-Ivaldi, Ferdinando A.; Pugh, Carla M.; Patton, James L.

2012-01-01

442

Milky Way HI Structure and Kinematics  

NASA Astrophysics Data System (ADS)

In galaxies, the gas distribution and kinematics are a reflection of the gravitational potential and the relevant physical processes. To better understand the dynamics of galactic systems, we investigated the atomic gas in the Milky Way. Using the Leiden/Argentine/Bonn (LAB) survey, we mapped the vertical structure of the Milky Way in atomic hydrogen. We reduced the complex structure of the warp to three simple Fourier spatial frequencies, and we showed that the vertical oscillations known as scalloping are local rather than global. We then used unsharp masking to produce perturbed surface density and thickness maps of the outer Milky Way disk. These maps show the presence of spiral arms out to at least 25 kpc from the Galactic center, and demonstrate that overdensities in the surface density are coincident with regions of reduced gas thickness. Using observations from the VLA Galactic Plane Survey (VGPS) and the Southern Galactic Plane Survey (SGPS), we constrained the rotation curve of the inner Galaxy and its first two vertical derivatives. We used global and local models to find the falloff in the rotation speed with distance from the plane is approximately -20 km/s/kpc. This result is consistent with the falloff m