JFKengine: A Jacobian and Forward Kinematics Generator
Fischer, K.N.
2003-02-13
During robot path planning and control the equations that describe the robot motions are determined and solved. Historically these expressions were derived analytically off-line. For robots that must adapt to their environment or perform a wide range of tasks, a way is needed to rapidly re-derive these expressions to take into account the robot kinematic changes, such as when a tool is added to the end-effector. The JFKengine software was developed to automatically produce the expressions representing the manipulator arm motion, including the manipulator arm Jacobian and the forward kinematic expressions. Its programming interface can be used in conjunction with robot simulation software or with robot control software. Thus, it helps to automate the process of configuration changes for serial robot manipulators. If the manipulator undergoes a geometric change, such as tool acquisition, then JFKengine can be invoked again from the control or simulation software, passing it parameters for the new arm configuration. This report describes the automated processes that are implemented by JFKengine to derive the kinematic equations and the programming interface by which it is invoked. Then it discusses the tree data structure that was chosen to store the expressions, followed by several examples of portions of expressions as represented in the tree. The C++ classes and their methods that implement the expression differentiation and evaluation operations are described. The algorithms used to construct the Jacobian and forward kinematic equations using these basic building blocks are then illustrated. The activity described in this report is part of a larger project entitled ''Multi-Optimization Criteria-Based Robot Behavioral Adaptability and Motion Planning'' that focuses on the development of a methodology for the generalized resolution of robot motion equations with time-varying configurations, constraints, and task objective criteria. A specific goal of this project is the implementation of this generalized methodology in a single general code that would be applicable to the motion planning of a wide class of systems and would automate many of the processes involved in developing and solving the motion planning and controls equations. This project is funded by the U.S. Department of Energy's Environmental Management Science Program (DOE-EMSP) as project EMSP no. 82794 and is transitioning to the DOE-Office of Biological and Environmental Research (OBER) as per FY-02.
Unseren, M.A.; Reister, D.B.
1995-07-01
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.
Improved numerical inverse kinematics for human pose estimation
NASA Astrophysics Data System (ADS)
Seo, Yung-Ho; Lee, Chil-Woo; Choi, Jong-Soo
2011-03-01
We propose a real-time pose estimation method that addresses the weaknesses of the numerical inverse kinematics method. Using conventional inverse kinematics based on the numerical method requires many iterations; moreover, a singularity in the Jacobian matrix as well as a local minimum problem can occur. To solve these problems, we propose an inverse kinematics method combined with an unscented Kalman filter (UKF) to recover intermediate joint information. Because the numerical inverse kinematics method optimizes a state, the solution can often converge to the local minimum and require many iterations. We use several sigma points for analysis to find the optimum state by using an unscented transform. The improved method using a UKF converges faster than the numerical inverse kinematics method for the global minimum of the existing inverse kinematics. We use 2-D image processes to extract body areas from the input images, and a 3-D reconstruction algorithm is used to estimate the 3-D positions of the extracted human body area. Using the improved method, we generate intermediate joints for each body part and the results show that the proposed method reduces the computational complexity and increases the accuracy of estimation compared to conventional numerical inverse kinematics.
Efficient Calculation of Jacobian and Adjoint Vector Products in Wave Propagational Inverse Problem
Santosa, Fadil
which models the physical phenomena. The inverse problems are often posed as a nonlinear dataÂ fittingEfficient Calculation of Jacobian and Adjoint Vector Products in Wave Propagational Inverse Problem propagational inverse problems arise in several applications including medical imaging and geophysical
Inverse Kinematic Solution Based on Decomposed Manipulability
Jihong Lee; K. T. Won
1999-01-01
For redundant robot manipulators, linear motion and angular motion are handled separately in solving inverse kinematics and trajectory planning. We apply the concept of decomposed specified manipulability to solve the inverse kinematic equation. With given joint velocity limits and given task velocity, we solve the inverse kinematic equation so that the linear velocity of the solution has maximum magnitude while
Inverse Kinematics Positioning Using Nonlinear Programming
Chai, Jinxiang
Inverse Kinematics Positioning Using Nonlinear Programming for Highly Articulated Figures JIANMIN the inverse kinematics problem is of special importance to an animator wishing to set a figure to a posture or performance. So, we approach this problem through nonlinear programming techniques. It has been successfully
Inverse kinematics Prof. Alessandro De Luca
De Luca, Alessandro
#12;Workspace of Fanuc R-2000i/165F WS1 (! WS2 for spherical wrist without joint limits) Robotics 1 4 at the origin) x y · p l1 l2 q1 q2 l1+l2 |l1-l2| 2 orientations 1 orientation (WS1 Robotics 1 5 #12;WristRobotics 1 Inverse kinematics Prof. Alessandro De Luca Robotics 1 1 #12;Inverse kinematics problem
Iterative inverse kinematics with manipulator configuration control
Grudic, G.Z.; Lawrence, P.D. [Univ. of British Columbia, Vancouver, British Columbia (Canada). Dept. of Electrical Engineering] [Univ. of British Columbia, Vancouver, British Columbia (Canada). Dept. of Electrical Engineering
1993-08-01
A new method, termed the offset modification method (OM method), for solving the manipulator inverse kinematics problem is presented. The OM method works by modifying the link offset values of a manipulator until it is possible to derive closed-form inverse kinematics equations for the resulting manipulator (termed the model manipulator). This procedure allows one to derive a set of three nonlinear equations in three unknowns that, when numerically solved, give an inverse kinematics solution for the original manipulator. The OM method can be applied to manipulators with any number of degrees of freedom, as long as the manipulator satisfies a given set of conditions (Theorem 1). The OM method is tested on a 6-degree-of-freedom manipulator that has no known closed-form inverse kinematics equations. It is shown that the OM method is applicable to real-time manipulator control, can be used to guarantee convergence to a desired endpoint position and orientation (if it exists), and allows one to directly choose which inverse kinematics solution the algorithm will converge to (as specified in the model manipulator closed-form inverse kinematics equations). Applications of the method to other 6-DOF manipulator geometries and to redundant manipulators (i.e. greater than 6 DOF geometries) are discussed.
Wrist-Partitioned Inverse Kinematic Accelerations and Manipulator Dynamics
Hollerbach, John M.
1983-04-01
An efficient algorithm is presented for the calculation of the inverse kinematic accelerations for a 6 degree-of-freedom manipulator with a spherical wrist. The inverse kinematic calculation is shown to work synergistically ...
Wrist-Partitioned, Inverse Kinematic Accelerations and Manipulator Dynamics
John M. Hollerbach; Gideon Sahar
1983-01-01
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,
Solution of inverse kinematic problem for serial robot using quaterninons
Emre Sariyildiz; Hakan Temeltas
2009-01-01
A new inverse kinematic solution for serial robot manipulators is represented in this paper. Major aims of this paper are to obtain singularity avoiding inverse kinematic solutions and formulize kinematic problems in a compact closed form. Our solution method is based on screw theory and it uses quaternions as a screw motion operator. Screw theory methods based on line transformation.
Directed Neutron Beams From Inverse Kinematic Reactions
NASA Astrophysics Data System (ADS)
Vanhoy, J. R.; Guardala, N. A.; Glass, G. A.
2011-06-01
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.
Inverse differential kinematics Prof. Alessandro De Luca
De Luca, Alessandro
"generalized" velocity (linear and angular) ! problems ! near a singularity of the Jacobian matrix (high q robot ! there is a sudden increase of the displacement/velocity of the first joint near !2= " (end motion q = JDLS(q) v . Robotics 1 13 q = J-1 (q) v . extremely large peak velocity of first joint!! very
Inverse Kinematic Analysis of Human Hand Thumb Model
NASA Astrophysics Data System (ADS)
Toth-Tascau, Mirela; Pater, Flavius; Stoia, Dan Ioan; Menyhardt, Karoly; Rosu, Serban; Rusu, Lucian; Vigaru, Cosmina
2011-09-01
This paper deals with a kinematic model of the thumb of the human hand. The proposed model has 3 degrees of freedom being able to model the movements of the thumb tip with respect to the wrist joint centre. The kinematic equations are derived based on Denavit-Hartenberg Convention and solved in both direct and inverse way. Inverse kinematic analysis of human hand thumb model reveals multiple and connected solutions which are characteristic to nonlinear systems when the number of equations is greater than number of unknowns and correspond to natural movements of the finger.
Computational neural learning formalisms for manipulator inverse kinematics
NASA Technical Reports Server (NTRS)
Gulati, Sandeep; Barhen, Jacob; Iyengar, S. Sitharama
1989-01-01
An efficient, adaptive neural learning paradigm for addressing the inverse kinematics of redundant manipulators is presented. The proposed methodology exploits the infinite local stability of terminal attractors - a new class of mathematical constructs which provide unique information processing capabilities to artificial neural systems. For robotic applications, synaptic elements of such networks can rapidly acquire the kinematic invariances embedded within the presented samples. Subsequently, joint-space configurations, required to follow arbitrary end-effector trajectories, can readily be computed. In a significant departure from prior neuromorphic learning algorithms, this methodology provides mechanisms for incorporating an in-training skew to handle kinematics and environmental constraints.
Inverse Kinematics in Biology: The Protein Loop Closure Problem
Rachel Kolodny; Leonidas J. Guibas; Michael Levitt; Patrice Koehl
2005-01-01
Assembling fragments from known protein structures is a widely used approach to construct structural models for new proteins. We de- scribe an application of this idea to an important inverse kinematics problem in structural biology: the loop closure problem. We have developed an algorithm for generating the conformations of can- didate loops that fit in a gap of given length
FPGA-Implementation of Inverse Kinematics and Servo Controller for Robot Manipulator
Ying-shieh Kung; Kuan-hsuan Tseng; Chia-sheng Chen; Hau-zen Sze; An-peng Wang
2006-01-01
The implementation of inverse kinematics and servo controller for robot manipulator using FPGA (Field Programmer Gate Array) is investigated in this paper. Firstly, the mathematical model and the servo controller of robot manipulator are described. Secondly, the inverse kinematics is formulated. Thirdly, the circuit design to implement the function of inverse kinematics and servo controller based on FPGA is introduced.
Reexamination of 6Li +p elastic scattering in inverse kinematics
NASA Astrophysics Data System (ADS)
Soukeras, V.; Pakou, A.; Cappuzzello, F.; Acosta, L.; Agodi, C.; Alamanos, N.; Bondi, M.; Carbone, D.; Cavallaro, M.; Cunsolo, A.; De Napoli, M.; Di Pietro, A.; Fernández-García, J. P.; Figuera, P.; Fisichella, M.; Foti, A.; Keeley, N.; Marquinez-Duran, G.; Martel, I.; Mazzocco, M.; Nicolosi, D.; Pierroutsakou, D.; Rusek, K.; Sgouros, O.; Stiliaris, E.; Strano, E.; Torresi, D.
2015-05-01
Elastic-scattering measurements have been performed for the 6Li +p system in inverse kinematics at the energies of 16, 20, 25, and 29 MeV. The heavy ejectile was detected by the large acceptance MAGNEX spectrometer at the Laboratori Nazionali del Sud in Catania, Italy. The results are considered in a Jeukenne-Lejeune-Mahaux and a continuum discretized coupled-channel calculation framework.
Jacobi inversion on strata of the Jacobian of the $C_{rs}$ curve $y^r = f(x)$. II
Matsutani, Shigeki
2010-01-01
Continuing previous work by the authors (J. Math. Soc. Japan 60 (2008) 1009-1044), this paper gives the precise order of vanishing of the $\\sigma$-function on a stratification of the Jacobian of a cyclic $C_{rs}$ curve. The result is expressed through combinatorial properties of the Schur functions, related to the stratification of Sato's infinite-dimensional Grassmann manifold.
Learning inverse kinematics: reduced sampling through decomposition into virtual robots.
de Angulo, Vicente Ruiz; Torras, Carme
2008-12-01
We propose a technique to speedup the learning of the inverse kinematics of a robot manipulator by decomposing it into two or more virtual robot arms. Unlike previous decomposition approaches, this one does not place any requirement on the robot architecture, and thus, it is completely general. Parametrized self-organizing maps are particularly adequate for this type of learning, and permit comparing results directly obtained and through the decomposition. Experimentation shows that time reductions of up to two orders of magnitude are easily attained. PMID:19022727
Kinematic Waveform Inversion: Application in Southwest Iberia Seismicity
NASA Astrophysics Data System (ADS)
Domingues, A. L.; Custodio, S.; Cesca, S.
2011-12-01
The seismic activity that affects the Portuguese territory occurs mainly and more frequently offshore, in the south and southwest of Mainland Portugal. The study of the Portuguese seismicity is conditioned by the poor azimuthal coverage, due to the geographic location of Portugal, and by the large sedimentary basin west of the straight of Gibraltar (Cadiz Basin). In this work we focus on the study of regional seismicity in Portugal (mostly offshore earthquakes) using a recently developed package - the KIWI (Kinematic Waveform Inversion) tools. This new technique performs point and finite source inversions at regional distances. The KIWI routine is a multi-step approach composed of 3 steps, finding different source parameters at different steps. At first, we assume a point source approximation. We initially retrieve the focal mechanism of the earthquake (strike, dip, and rake), the seismic scalar moment M0 and the depth. This inversion step is performed in the spectral domain, by fitting amplitude spectra. In the second step, compressive and dilatation quadrants are retrieved, which is carried out in the time domain. Refined latitude and longitude for the centroid, as well as an earthquake origin time, are also given at this time. The final step of the inversion consists of a simplified finite-fault inversion. We assume the eikonal source model, and determine parameters such as the fault plane orientation (discrimination between fault and auxiliary plane), radius (rupture extension), nucleation point coordinates (indicative of directivity effects) and average rupture velocity of the earthquake. This inversion is performed in the frequency domain by fitting amplitude spectra in a wider frequency band (including higher frequencies). This multi-step approach has the advantage of using different inversion methods, seismic phases and range of frequencies to infer specific parameters. In this work we study 17 regional earthquakes occurred in Southwest Iberia between 2007 and 2009 with moderate magnitude (3.3 to 4.4). The small magnitude of these earthquakes prevents their study with the third step of the algorithm. The solutions obtained are evaluated by a quality criteria and compared with other moment tensor solutions. The quality factor is based on the number of stations and on the misfit between the recorded and the synthetic waveforms. Apart from this study another offshore event was analyzed. The earthquake occurred SW of St Vincent Cape on February 12, 2007 with Mw 5.9. In this study the KIWI tools were employed to infer both the point and finite source parameters of this earthquake. The results of the kinematic source inversion step indicate that the 2007 HAP earthquake ruptured a plane trending WNW-ESE, whereas previous studies suggest that the conjugate fault plane (ENE-WSW) is the true rupture plane. The proposed solution also indicates that the earthquake occurred within the SWIM fault-zone. However, the 46° dip is difficult to reconcile with the sub-vertical nature of the SWIM faults.
On the inverse kinematics of redundant manipulators: characterization of the self-motion manifolds
Joel W. Burdick
1989-01-01
The author takes a global rather than instantaneous look at the inverse kinematics of redundant manipulators. This approach is based on a manifold mapping reformulation of manipulator kinematics. While the kinematic problem has an infinite number of solutions for redundant manipulators, the infinity of solutions can be grouped into a finite and bounded set of disjoint continuous manifolds. Each of
An open mapping theorem using unbounded generalized Jacobians
V. Jeyakumar; D. T. Luc
2002-01-01
In this paper, three key theorems (the open mapping theorem, the inverse function theorem, and the implicit function theorem) for contin- uously differentiable maps are shown to hold for nonsmooth continuous maps which are not necessarily Lipschitz continuous. The significance of these extensions is that they are given using generalized Jacobians, called approximate Jacobians. The approximate Jacobian which replaces the
NASA Technical Reports Server (NTRS)
Kelmar, Laura; Khosla, Pradeep K.
1990-01-01
An algorithm is proposed for automatically generating both the forward and inverse kinematics of a serial-link N-degree-of-freedom reconfigurable manipulator (RM). Generation of the kinematic equations that govern a modular manipulator starts with geometric descriptions of the units, or modules, as well as their sequence in the manipulator. This geometric information is used to obtain the Denavit-Hartenberg (DH) parameters of an RM. The DH kinematic parameters are then used to obtain the forward kinematic transformation of the system. The problem of obtaining the inverse kinematics of RMs is addressed, and the idea of scaling an RM to automate the inverse kinematics and make the procedure as general as possible is proposed.
An Efficient Energy Transfer Inverse Kinematics Jing Huang and Catherine Pelachaud
Pelachaud, Catherine
to control virtual vertebral living creatures, such as human beings or animals, which frequently appear in films and video games. Inverse Kinematics (IK) is a method for computing joint rotation values
A Closed Form Solution for Inverse Kinematics of Robot Manipulator with Redundancy
Chang, Pyung H.
1986-03-01
A closed form equation for inverse kinematics of manipulator with redundancy is derived, using the Lagrangian multiplier method. The proposed equation is proved to provide the exact equilibrium state for the resolved ...
Seeing the world topsy-turvy: The primary role of kinematics in biological motion inversion effects.
Fitzgerald, Sue-Anne; Brooks, Anna; van der Zwan, Rick; Blair, Duncan
2014-01-01
Physical inversion of whole or partial human body representations typically has catastrophic consequences on the observer's ability to perform visual processing tasks. Explanations usually focus on the effects of inversion on the visual system's ability to exploit configural or structural relationships, but more recently have also implicated motion or kinematic cue processing. Here, we systematically tested the role of both on perceptions of sex from upright and inverted point-light walkers. Our data suggest that inversion results in systematic degradations of the processing of kinematic cues. Specifically and intriguingly, they reveal sex-based kinematic differences: Kinematics characteristic of females generally are resistant to inversion effects, while those of males drive systematic sex misperceptions. Implications of the findings are discussed. PMID:25469217
Xuguang Wang
1999-01-01
In this paper, the computational problem of inverse kinematics of arm prehension movements was investigated. How motions of each joint involved in arm movements can be used to control the end-effector (hand) position and orientation was first examined. It is shown that the inverse kinematics problem due to the kinematic redundancy in joint space is ill-posed only at the control
Dhananjay P. Mehendale
2009-12-29
The direct or algorithmic approach for the Jacobian problem, consisting of the direct construction of the inverse polynomials, using the principle and derived Jacobi conditions discussed in section 2.4 is proposed. The approach is extendable to higher dimensions by identically proceeding on similar lines. As per the result of Bass, Connell, and Right [3] it is enough to show the conjecture to be true for cubic polynomials of special type in n variables. The method of proof for two and three variables cases is discussed first and it is shown that the extension for the several variables case is straightforward. Thus, we show that the problem can be solved completely using the important reduction of the problem to a homogeneous-cubic degree obtained in [3]. The other objective of the paper is to point out the merits of the direct or algorithmic approach for the Jacobian problem, subsequently leading to main objective of settling it in the end using the result in [3].
NASA Astrophysics Data System (ADS)
Zielke, O.; McDougall, D.; Mai, P. M.; Babuska, I.
2014-12-01
One fundamental aspect of seismic hazard mitigation is gaining a better understanding of the rupture process. Because direct observation of the relevant parameters and properties is not possible, other means such as kinematic source inversions are used instead. By constraining the spatial and temporal evolution of fault slip during an earthquake, those inversion approaches may enable valuable insights in the physics of the rupture process. However, due to the underdetermined nature of this inversion problem (i.e., inverting a kinematic source model for an extended fault based on seismic data), the provided solutions are generally non-unique. Here we present a statistical (Bayesian) inversion approach based on an open-source library for uncertainty quantification (UQ) called QUESO that was developed at ICES (UT Austin). The approach has advantages with respect to deterministic inversion approaches as it provides not only a single (non-unique) solution but also provides uncertainty bounds with it. Those uncertainty bounds help to qualitatively and quantitatively judge how well constrained an inversion solution is and how much rupture complexity the data reliably resolve. The presented inversion scheme uses only tele-seismically recorded body waves but future developments may lead us towards joint inversion schemes. After giving an insight in the inversion scheme ifself (based on delayed rejection adaptive metropolis, DRAM) we explore the method's resolution potential. For that, we synthetically generate tele-seismic data, add for example different levels of noise and/or change fault plane parameterization and then apply our inversion scheme in the attempt to extract the (known) kinematic rupture model. We conclude with exemplary inverting real tele-seismic data of a recent large earthquake and compare those results with deterministically derived kinematic source models provided by other research groups.
Pain, S. D. [Rutgers University; Bardayan, Daniel W [ORNL; Blackmon, Jeff C [ORNL; Chae, K. Y. [University of Tennessee, Knoxville (UTK); Chipps, K. [Colorado School of Mines, Golden; Cizewski, J. A. [Rutgers University; Hatarik, Robert [Rutgers University; Johnson, Micah [ORNL; Jones, K. L. [University of Tennessee, Knoxville (UTK); Kapler, R. [University of Tennessee, Knoxville (UTK); Kozub, R. L. [Tennessee Technological University; Livesay, Jake [ORNL; Matei, Catalin [Oak Ridge Associated Universities (ORAU); Moazen, Brian [University of Tennessee, Knoxville (UTK); Nesaraja, Caroline D [ORNL; O'Malley, Patrick [Rutgers University; Smith, Michael Scott [ORNL; Swan, T. P. [University of Surrey, UK; Thomas, J. S. [Rutgers University; Wilson, Gemma L [ORNL
2009-01-01
The development of high quality radioactive beams has made possible the measurement of transfer reactions in inverse kinematics on unstable nuclei. Measurement of (d,p) reactions on neutron-rich nuclei yield data on the evolution of nuclear structure away from stability, and are of astrophysical interest. Experimentally, (d,p) reactions on heavy (Z=50) fission fragments are complicated by the strongly inverse kinematics, and relatively low beam intensities. Consequently, ejectile detection with high resolution in position and energy, a high dynamic range and a high solid angular coverage is required. The Oak Ridge Rutgers University Barrel Array (ORRUBA) is a new silicon detector array optimized for the measurement of (d,p) reactions in inverse kinematics.
Dead-reckoning inverse and direct kinematic solution of a 4W independent driven rover
E. A. Marti?nez-Garci?a; O. Mar; R. Torres-Cordoba
2010-01-01
We tackle the problem of trajectory control of a four-wheel driven skid-steering (4WDSS) robotic platform with asynchronous wheels velocity. A practical mathematical formulation for solving inverse and direct kinematics is provided. This approach also includes the formulation and implementation of a home made arrange of accelerometers to infer robot displacements in global coordinates system. Although we provide a direct kinematics
AN INVERSE KINEMATIC MATHEMATICAL MODEL USING GROEBNER BASIS THEORY FOR
kinematics, joint configurations of the shoulder and elbow are found to place the wrist at a specific (Kendricks, 2007; Hartenberg, 1995). In robotics, the IK- problem is most widely used to determine object capability, efficiency, and accuracy for various robot manipulators. It's been proven that Groebner Basis
Samy F. M. Assal; Keigo Watanabe; Kiyotaka Izumi
2006-01-01
In this paper, a neural network (NN)-based inverse kinematics problem of redundant manipulators subject to joint limits is presented. The Widrow-Hoff NN with an adaptive learning algorithm derived by applying Lyapunov stability theory is introduced. Since the inverse kinematics has an infinite number of joint angle vectors, a fuzzy neural network (FNN) is designed to provide an approximate value for
Attractor-based computation with reservoirs for online learning of inverse kinematics
R. Felix Reinhart; Jochen J. Steil
2009-01-01
We implement completely data driven and e!cient online learning from temporally correlated data in a reservoir network setup. We show that attractor states rather than transients are used for computation when learning inverse kinematics for the redundant robot arm PA-10. Our findings shade also light on the role of output feedback. In robotics, learning is typically constrained by limited resources
Direct and Inverse Kinematics of a Novel Tip-Tilt-Piston Parallel Manipulator
NASA Technical Reports Server (NTRS)
Tahmasebi, Farhad
2004-01-01
Closed-form direct and inverse kinematics of a new three degree-of-freedom (DOF) parallel manipulator with inextensible limbs and base-mounted actuators are presented. The manipulator has higher resolution and precision than the existing three DOF mechanisms with extensible limbs. Since all of the manipulator actuators are base-mounted; higher payload capacity, smaller actuator sizes, and lower power dissipation can be obtained. The manipulator is suitable for alignment applications where only tip, tilt, and piston motions are significant. The direct kinematics of the manipulator is reduced to solving an eighth-degree polynomial in the square of tangent of half-angle between one of the limbs and the base plane. Hence, there are at most 16 assembly configurations for the manipulator. In addition, it is shown that the 16 solutions are eight pairs of reflected configurations with respect to the base plane. Numerical examples for the direct and inverse kinematics of the manipulator are also presented.
3D Motion Planning Algorithms for Steerable Needles Using Inverse Kinematics
Duindam, Vincent; Xu, Jijie; Alterovitz, Ron; Sastry, Shankar; Goldberg, Ken
2010-01-01
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. PMID:21359051
Fu, Zhongtao; Yang, Wenyu; Yang, Zhen
2013-08-01
In this paper, we present an efficient method based on geometric algebra for computing the solutions to the inverse kinematics problem (IKP) of the 6R robot manipulators with offset wrist. Due to the fact that there exist some difficulties to solve the inverse kinematics problem when the kinematics equations are complex, highly nonlinear, coupled and multiple solutions in terms of these robot manipulators stated mathematically, we apply the theory of Geometric Algebra to the kinematic modeling of 6R robot manipulators simply and generate closed-form kinematics equations, reformulate the problem as a generalized eigenvalue problem with symbolic elimination technique, and then yield 16 solutions. Finally, a spray painting robot, which conforms to the type of robot manipulators, is used as an example of implementation for the effectiveness and real-time of this method. The experimental results show that this method has a large advantage over the classical methods on geometric intuition, computation and real-time, and can be directly extended to all serial robot manipulators and completely automatized, which provides a new tool on the analysis and application of general robot manipulators. PMID:23918347
Kinematical synthesis of an inversion of the double linked fourbar for morphing wing applications
NASA Astrophysics Data System (ADS)
Aguirrebeitia, J.; Avilés, R.; Fernández, I.; Abasolo, M.
2013-03-01
This paper presents the kinematical features of an inversion of the double linked fourbar for morphing wing purposes. The structure of the mechanism is obtained using structural synthesis concepts, from an initial conceptual schematic. Then, kinematic characteristics as instant center of rotation, lock positions, dead point positions and uncertainty positions are derived for this mechanism in order to face the last step, the dimensional synthesis; in this sense, two kinds of dimensional synthesis are arranged to guide the wing along two positions, and to fulfill with the second one some aerodynamic and minimum actuation energy related issues.
NASA Astrophysics Data System (ADS)
Melgar, D.; Bock, Y.
2014-12-01
Rapid kinematic slip inversions immediately following earthquake rupture is traditionally limited to teleseismic data and delayed many hours after large events. Regional data such as strong motion is difficult to incorporate quickly into images of the source process because baseline offsets render the long period portion of the recording unreliable. Recently it's been demonstrated that high rate GPS can potentially produce rapid slip inversions for large events but is limited to very long periods. With an example of the 2011 M9 Tohoku-oki event we will demonstrate that the optimal on-the-fly combination of GPS and strong motion through a seismogeodetic Kalman filter produces reliable, broadband strong motion displacement and velocity waveforms that can be used for kinematic inversion. Through joint inversion of displacement and velocity waveforms we will show that it is possible to obtain a broadband image of the source. Furthermore, we will also show that it is possible to include offshore geophysical observables such as sea surface measurements of tsunami propagation from GPS buoys and ocean bottom pressure sensors into the kinematic inversion. These data better constrain the shallowest part of rupture. We will use the time-dependent deformation of bathymetry predicted from the inversion results as an initial condition for tsunami propagation and inundation modeling. Through a comparison to post-event survey observations we will demonstrate that it is possible to reproduce the inundation pattern along the coastline in great detail and argue that detailed site-specific forecast of tsunami intensity is achievable with current methods and instrumentation.
Cortical network modeling for inverse kinematic computation of an anthropomorphic finger.
Gentili, Rodolphe J; Oh, Hyuk; Molina, Javier; Contreras-Vidal, José L
2011-01-01
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
Infinite dimensional generalized Jacobian
NASA Astrophysics Data System (ADS)
Páles, Zsolt; Zeidan, Vera
2008-08-01
The extension to infinite dimensional domains of Clarke's generalized Jacobian is the focus of this paper. First, a generalization of a Fabian-Preiss theorem to the infinite dimensional setting is obtained. As a consequence, a new formula relating the Clarke's generalized Jacobians corresponding to finite dimensional spaces K, L with K[subset, double equals]L is established. Furthermore, in the infinite dimensional case, basic properties pertaining the generalized Jacobian are developed and then an identification of this set-valued map is produced. Applications of these results in the form of chain rules including sum and product rules, and a computational formula for continuous selections are derived.
Approximating a Robot Inverse Kinematics Solution Using Fuzzy Logic Tuned by Genetic Algorithms
C.-Y. Chen; M.-G. Her; Y.-C. Hung; M. Karkoub
2002-01-01
A new scheme based on recursive fuzzy logic is presented in this paper for solving the point-to-point inverse kinematics problem\\u000a of serial robots. To improve the convergence problem in the whole workspace, the membership functions of the fuzzy logic are\\u000a searched for, tuned, and optimised using a simple genetic algorithm. A dominant joint, which brings the end-effect closer\\u000a to the
Cortex inspired model for inverse kinematics computation for a humanoid robotic finger.
Gentili, Rodolphe J; Oh, Hyuk; Molina, Javier; Reggia, James A; Contreras-Vidal, José L
2012-01-01
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
Inverse kinematic and forward dynamic models of the 2002 Denali fault earthquake, Alaska
Oglesby, D.D.; Dreger, Douglas S.; Harris, R.A.; Ratchkovski, N.; Hansen, R.
2004-01-01
We perform inverse kinematic and forward dynamic models of the M 7.9 2002 Denali fault, Alaska, earthquake to shed light on the rupture process and dynamics of this event, which took place on a geometrically complex fault system in central Alaska. We use a combination of local seismic and Global Positioning System (GPS) data for our kinematic inversion and find that the slip distribution of this event is characterized by three major asperities on the Denali fault. The rupture nucleated on the Susitna Glacier thrust fault, and after a pause, propagated onto the strike-slip Denali fault. Approximately 216 km to the east, the rupture abandoned the Denali fault in favor of the more southwesterly directed Totschunda fault. Three-dimensional dynamic models of this event indicate that the abandonment of the Denali fault for the Totschunda fault can be explained by the Totschunda fault's more favorable orientation with respect to the local stress field. However, a uniform tectonic stress field cannot explain the complex slip pattern in this event. We also find that our dynamic models predict discontinuous rupture from the Denali to Totschunda fault segments. Such discontinuous rupture helps to qualitatively improve our kinematic inverse models. Two principal implications of our study are (1) a combination of inverse and forward modeling can bring insight into earthquake processes that are not possible with either technique alone, and (2) the stress field on geometrically complex fault systems is most likely not due to a uniform tectonic stress field that is resolved onto fault segments of different orientations; rather, other forms of stress heterogeneity must be invoked to explain the observed slip patterns.
NASA Technical Reports Server (NTRS)
Podhorodeski, R. P.; Fenton, R. G.; Goldenberg, A. A.
1989-01-01
Using a method based upon resolving joint velocities using reciprocal screw quantities, compact analytical expressions are generated for the inverse solution of the joint rates of a seven revolute (spherical-revolute-spherical) manipulator. The method uses a sequential decomposition of screw coordinates to identify reciprocal screw quantities used in the resolution of a particular joint rate solution, and also to identify a Jacobian null-space basis used for the direct solution of optimal joint rates. The results of the screw decomposition are used to study special configurations of the manipulator, generating expressions for the inverse velocity solution for all non-singular configurations of the manipulator, and identifying singular configurations and their characteristics. Two functions are therefore served: a new general method for the solution of the inverse velocity problem is presented; and complete analytical expressions are derived for the resolution of the joint rates of a seven degree of freedom manipulator useful for telerobotic and industrial robotic application.
The Kinematics of Robotic Wrists
Rodney G. Roberts; Daniel W. Repperger
1994-01-01
This paper examines the kinematics of robotic wrists by using the singular value decomposition (SVD) of the wrist Jacobian. Since the manipulator Jacobian of a wrist is relatively simple, it is possible to calculate the SVD in closed form via a simple matrix factorization. Once this has been accomplished, a variety of issues can be examined including kinematic singularities and
Utrecht, Universiteit
Insights into the kinematics of a volcanic caldera drop: Probabilistic finite-source inversion Editor: R.D. van der Hilst Keywords: volcanic caldera Bárdarbunga Iceland finite-source inversion critically on information concerning the interaction between the caldera and the underlying magma chamber
NASA Astrophysics Data System (ADS)
Castro-Artola, O.; Iglesias Mendoza, A.
2012-04-01
Aiming to obtain some information about the rupture process of intermediate to great earthquakes, many waveform inversion schemes have been proposed. Usual methods involve several subfaults on the fault plane to obtain a detailed image of the kinematic rupture process. On the other hand, it has been questioned the resolution over obtained paramters on the inversion process. In the literature contradictory results can be found for the same earthquake, using different schemes. For this reason, recently, simplified schemes of the rupture process have been proposed, while not providing details it can recover their main characteristics. In this work we propose a modification of the Cotton & Campillo (1995) inversion scheme, while unlike considering the problem as a "rupture process tomographic inversion", we invert the main characteristics assuming simplified geometries (ellipses). Based on the work quoted, the direct problem is reparameterized including one or two ellipses in which the maximum displacement is distributed. For the first ellipse, the position of the center within the fault plane, the major and minor semi-axis are inverted. For the second one we invert the position with respect to the first ellipse and the two semi-axis. To avoid the linearization of the problem, we use a simulated annealing scheme for inversion. When there is not enough evidence of the proper fault plane, we perform an inversion for the two nodal planes published to solve the ambiguity between the auxiliary plane and the fault plane that a point source inversion schemes involve. We tested our method for the well studied earthquake September 30th 1999 Oaxaca (Mw=7.5) (e.g. Hernandez et al., 2001) which is one of the intraslab earthquakes within the Northamerican Plate of moderate magnitude and well recorded. The scheme is evaluated as well with the data generated by the "Escenario 2011" framework for an hypothetical earthquake in Guerrero, Mexico. Results will give us the opportunity to evaluate their later routinary implementation to the earthquakes occurring within Mexico.
Kinematically redundant robot manipulators
NASA Technical Reports Server (NTRS)
Baillieul, J.; Hollerbach, J.; Brockett, R.; Martin, D.; Percy, R.; Thomas, R.
1987-01-01
Research on control, design and programming of kinematically redundant robot manipulators (KRRM) is discussed. These are devices in which there are more joint space degrees of freedom than are required to achieve every position and orientation of the end-effector necessary for a given task in a given workspace. The technological developments described here deal with: kinematic programming techniques for automatically generating joint-space trajectories to execute prescribed tasks; control of redundant manipulators to optimize dynamic criteria (e.g., applications of forces and moments at the end-effector that optimally distribute the loading of actuators); and design of KRRMs to optimize functionality in congested work environments or to achieve other goals unattainable with non-redundant manipulators. Kinematic programming techniques are discussed, which show that some pseudo-inverse techniques that have been proposed for redundant manipulator control fail to achieve the goals of avoiding kinematic singularities and also generating closed joint-space paths corresponding to close paths of the end effector in the workspace. The extended Jacobian is proposed as an alternative to pseudo-inverse techniques.
34P(7Li,7Be+?) reaction at 100A??MeV in inverse kinematics.
Zegers, R G T; Meharchand, R; Shimbara, Y; Austin, Sam M; Bazin, D; Brown, B A; Diget, C Aa; Gade, A; Guess, C J; Hausmann, M; Hitt, G W; Howard, M E; King, M; Miller, D; Noji, S; Signoracci, A; Starosta, K; Tur, C; Vaman, C; Voss, P; Weisshaar, D; Yurkon, J
2010-05-28
We report on the first successful extraction of a ?+ Gamow-Teller strength distribution from a radioactive isotope in an intermediate-energy charge-exchange experiment in inverse kinematics. The (7Li,7Be+?(429??keV)) reaction at 100A??MeV was used to measure Gamow-Teller transition strengths from 34P to states in 34Si. The results show that little mixing occurs between sd and pf shell configurations for the low-lying 0+ and 2+ states even though 34Si neighbors the island of inversion and low-lying 2?? intruder states exist. Shell-model calculations in the sdpf model space are consistent with these findings. PMID:20867091
Alpha-particle capture reactions in inverse kinematics relevant to p-process nucleosynthesis
NASA Astrophysics Data System (ADS)
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
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.
Integrated Analytic and Linearized Inverse Kinematics for Precise Full Body Interactions
NASA Astrophysics Data System (ADS)
Boulic, Ronan; Raunhardt, Daniel
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.
An inverse kinematics algorithm for a highly redundant variable-geometry-truss manipulator
NASA Technical Reports Server (NTRS)
Naccarato, Frank; Hughes, Peter
1989-01-01
A new class of robotic arm consists of a periodic sequence of truss substructures, each of which has several variable-length members. Such variable-geometry-truss manipulator (VGTMs) are inherently highly redundant and promise a significant increase in dexterity over conventional anthropomorphic manipulators. This dexterity may be exploited for both obstacle avoidance and controlled deployment in complex workspaces. The inverse kinematics problem for such unorthodox manipulators, however, becomes complex because of the large number of degrees of freedom, and conventional solutions to the inverse kinematics problem become inefficient because of the high degree of redundancy. A solution is presented to this problem based on a spline-like reference curve for the manipulator's shape. Such an approach has a number of advantages: (1) direct, intuitive manipulation of shape; (2) reduced calculation time; and (3) direct control over the effective degree of redundancy of the manipulator. Furthermore, although the algorithm was developed primarily for variable-geometry-truss manipulators, it is general enough for application to a number of manipulator designs.
N. Simaan; M. Shoham
2003-01-01
This paper presents a closed-form formulation and geometrical interpretation of the derivatives of the Jacobian matrix of fully parallel robots with respect to the moving platforms' position\\/orientation variables. Similar to the Jacobian matrix, these derivatives are proven to be also groups of lines that together with the lines of the instantaneous direct kinematics matrix govern the singularities of the active
Development of a new Recoil Distance Technique using Coulomb Excitation in Inverse Kinematics
NASA Astrophysics Data System (ADS)
Rother, Wolfram; Dewald, Alfred; Ilie, Gabriela; Pissulla, Thomas; Melon, Barbara; Jolie, Jan; Pascovici, Gheorghe; Iwasaki, Hironori; Hackstein, Matthias; Zell, Karl-Oskar; Julin, Rauno; Jones, Peter; Greenlees, Paul; Rahkila, Panu; Uusitalo, Juha; Scholey, Cath; Harissopulos, Sotirios; Lagoyannis, Anastasios; Konstantinopoulos, Theodore; Grahn, Tuomas; Balabanski, Dimiter; Petkov, Pavel
2009-01-01
We report on an experiment using Coulomb excitation in inverse kinematics in combination with the plunger technique for measuring lifetimes of excited states of the projectiles. Aside from the investigation of E(5) features in 128Xe, the aim was to explore the special features of such experiments which are also suited to be used with radioactive beams. The measurement was performed at the JYFL with the Köln coincidence plunger device and the JUROGAM spectrometer using a 128Xe beam impinging on a natFe target at a beam energy of 525 MeV. Recoils were detected by means of 32 solar cells placed at extreme forward angles. Particle-gated ?-singles and ??-coincidences were measured at different target-degrader distances. Details of the experiment and first results are presented.
NASA Technical Reports Server (NTRS)
Fielding, Eric; Sladen, Anthony; Avouac, Jean-Philippe; Li, Zhenhong; Ryder, Isabelle; Burgmann, Roland
2008-01-01
The presentations explores kinematics of the Wenchaun-Beichuan earthquake using data from ALOS, Envisat, and teleseismic recordings. Topics include geomorphic mapping, ALOS PALSAR range offsets, ALOS PALSAR interferometry, Envisat IM interferometry, Envisat ScanSAR, Joint GPS-InSAR inversion, and joint GPS-teleseismic inversion (static and kinematic).
Mavroidis, Constantinos
1994-01-01
Robotica (1994) volume 12, pp 421-430. © 1994 Cambridge University Press Inverse kinematics of six. Bidaud Laboratoire de Robotique de Paris, Universite Pierre et Marie Curie, Tour 66, 2eme etage, 4 Place to the inverse kinematics problem of the GMF Arc Mate welding manipulator. In spite of its geometry
Zhang Shuzhen; Huang Jianlong; Kong Minxiu; Sun Lining
2010-01-01
For the RRRR motion chain, a kind of sub-problem which can be described as rotating about four not intersecting axes to a given point and adjacent axes are parallel or vertical intersecting or vertical skew is proposed. By combining analytic geometry and screw theory exponential product method, the inverse kinematics solution of the RRRR motion chain is derived, and joint
McCaffrey, Robert
Block kinematics of the PacificNorth America plate boundary in the southwestern United StatesNorth America plate boundary in the southwestern United States from inversion of GPS, seismological of the southwestern United States (30°41°N) is represented by a finite number of rotating, elastic-plastic spherical
On the kinematic design of spherical three-degree-of-freedom parallel manipulators
Gosselin, C.M.; Lavoie, E. (Univ. Laval, Ste.-Foy (Canada))
1993-08-01
This article studies the kinematic design of different types of spherical three-degree-of-freedom parallel manipulators. The mechanical architectures presented have been introduced elsewhere. However, designs having at least one isotropic configuration are suggested here for the first time. Isotropic configurations are defined, in turn, as those configurations in which the Jacobian matrix, mapping the angular velocity vector of the effector into the joint velocities, is proportional to an orthogonal matrix. First, a review of the direct and inverse kinematics of spherical three-degree-of-freedom parallel manipulators is outlined, and a general form for the Jacobian matrix is given. Parallel manipulators with revolute or prismatic actuators are discussed. Then, the concept of kinematic conditioning is recalled and used as a performance index for the optimization of the manipulators. It is shown that this leads to designs having at least one isotropic configuration. Finally, a few examples of such designs are presented. 15 refs.
Unseren, M.A.
1993-04-01
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.
NASA Astrophysics Data System (ADS)
Heimann, Sebastian; Sudhaus, Henriette; Wang, Rongjiang; Cesca, Simone; Dahm, Torsten
2014-05-01
The notorious discrepancies among finite fault slip inversion results have attracted much attention over the last years. In consequence, much effort has been put into methods to improve the robustness of such inversions and to quantify uncertainties on results. The techniques exploited include controlling the smoothness of the inferred slip distribution, reducing dimensionality of parameter-space, propagation of observational errors through Bayesian inference, Monte-Carlo modelling and bootstrapping. The difficulties in earthquake finite source parameter estimation arise from three distinct origins: (1) observational errors, (2) the (in)ability of the earthquake source model to represent nature, and (3) mismodelling of synthetic seismograms. While observational errors can often be formally included in the source parameter estimation process, the latter two are much harder to to handle. Appropriateness of the source model (2) is hard to achieve because more realistic models require more model parameters and quickly lead to underdetermined systems. Mismodelling of synthetic seismograms (3) has not been investigated much, probably because the technical effort to deal with it is usually high (because forward modelling may have to be repeated for many earth model variations). In this presentation, we will show that freely available precomputed Green's functions for ensembles of different earth models will make such investigations feasible for routine practice. We will illustrate this with a synthetic test case of a regional kinematic source parameter optimization. The presented work is closely related with the development of a new open source Python toolbox for the handling of precomputed Green's functions and for synthetic seismogram generation (http://emolch.github.io/pyrocko/gf). Ultimately, we would like to launch a community driven open access Green's function sharing platform and web services for synthetic seismogram and test scenario generation (http://kinherd.org/).
NASA Astrophysics Data System (ADS)
Alkhazov, G. D.; Vorobyov, A. A.; Dobrovolsky, A. V.; Inglessi, A. G.; Korolev, G. A.; Khanzadeev, A. V.
2015-05-01
In order to study the spatial structure of exotic nuclei, it was proposed at the Petersburg Nuclear Physics Institute (PNPI) to measure the differential cross section for small-angle proton elastic scattering in inverse kinematics. Several experiments in beams of 0.7-GeV/nucleon exotic nuclei were performed at the heavy-ion accelerator facility of GSI (Gesellschaft für Schwerionenforschung, Darmstadt, Germany) by using the IKAR ionization spectrometer developed at PNPI. The IKAR ionization chamber filled with hydrogen at a pressure of 10 bar served simultaneously as a target and as a recoil-proton detector, which measured the recoil-proton energy. The beam-particle scattering angle was also measured. The results obtained for the cross sections in question were analyzed on the basis of the Glauber-Sitenko theory using phenomenological nuclear-density distributions with two free parameters. Nuclear-matter distributions and root-mean-square radii were found for the nuclei under investigation. The size of the halo in the 6He, 8He, 11Li, and 14Be nuclei was determined among other things. Information about neutron distributions in nuclei was deduced by combining the data obtained here with the known values of the radii of proton distributions. A sizable neutron skin was revealed in the 8Li, 9Li, and 12Be nuclei.
Measurement of the ^134Te(d,p)^135Te Reaction in Inverse Kinematics
NASA Astrophysics Data System (ADS)
Pain, Steven
2007-10-01
The development of high quality radioactive beams, such as those at the HRIBF at ORNL, has made possible the performance of transfer reactions on unstable nuclei. Measurements of (d,p) reactions on n-rich fission fragments yield data on nuclear structure away from stability, and are of astrophysical interest due to the proximity to suggested r- process paths. The energies and spectroscopic information of single-particle states near to shell closures are of particular importance, since they provide both an important constraint on nuclear structure models and are directly relevant to direct neutron-capture cross sections. The single-neutron states in ^ 135Te, one neutron beyond the N=82 shell closure, are of particular interest, both for r-process nucleosynthesis and its relevance to an isotopic anomaly of Xe found in pre-solar meteoritic grains. The ^134Te(d,p)^135Te reaction has been measured in inverse kinematics at the HRIBF utilizing a beam of ^134Te at 643 MeV and a deuterated plastic target. Proton ejectiles were detected forward and backwards of ?lab = 90^o using an early implementation of the Oak Ridge Rutgers University Barrel Array (ORRUBA) in conjunction with SIDAR. Details of the experiment and the current stage of the data analysis will be presented.
Direct measurement of 38K(p , ?) 39Ca in inverse kinematics
NASA Astrophysics Data System (ADS)
Lotay, Gavin; Christian, Gregory; Burke, Devin; Chen, Alan; Connolly, Devin; Davids, Barry; Fallis, Jenniffer; Hager, Ulrike; Hutcheon, Dave; Mahl, Adam; Rojas, Alex; Ruiz, Chris; Sun, Xuan
2014-09-01
Sensitivity studies have identified 38K(p , ?) 39Ca as one of a handful of significant reactions in ONe novae, with the potential to change 38Ar, 39K, and 40Ca abundances in ONe ejecta by factors of ~18, ~17 and ~24, respectively. We have performed the first ever measurement of this reaction using the DRAGON recoil mass separator at TRIUMF. The experiment was performed in inverse kinematics using a beam of radioactive 38K. To date, this is the most massive projectile ever used in a radiative capture experiment. The astrophysical reaction rate is expected to be dominated by low- l resonances inside the Gamow window. Hence we have focused our efforts on the resonances at Ec.m. = 386, 515, and 689 keV. In this talk, I will present an overview of the experiment and data analysis and show preliminary resonance strengths (or upper limits) measured at each of the three energies. Finally, I will discuss the astrophysical implications of the measurements as they relate to ONe novae.
Manipulator inverse kinematics for untimed end-effector trajectories with ordinary singularities
Kieffer, J. (Univ. of Hull (United Kingdom))
1992-06-01
This article addresses the following inverse kinematics problem: given an untimed spatial end-effector trajectory, determine joint trajectories that are consistent with its execution. An algorithm for the continuous iterative solution of this problem for six-degree-of-freedom manipulators of arbitrary structure is presented. The main idea of this algorithm is that it converges with equal ease at both regular configurations and certain ordinary singularities. Ordinary singularities (herein defined) depend on the given end-effector trajectory, as well as the manipulator configuration, and represent dead points where the end effector (but not the manipulator) must pause during trajectory execution. The algorithm is based on the predictor-corrector method of path following using (1) a newly developed second-order predictor, (2) a first-order Newton method corrector, and (3) the idea of including the end effector's position (along its trajectory) as a dependent (rather than independent) variable in the formulation. Both the predictor and the corrector are derived from Taylor series expansion of the 4 [times] 4 matrix equation of closure and require only the solution of linear systems of equations. Examples are given that demonstrate the algorithm's ability to pass through ordinary singularities to determine alternate joint trajectories for the same end-effector trajectory. These examples also show how ordinary singularities can be included in manipulator motions that are similar to a boxer's jab or a runner's kick.
NASA Astrophysics Data System (ADS)
Reifarth, René; Litvinov, Yuri A.; Endres, Anne; Göbel, Kathrin; Heftrich, Tanja; Glorius, Jan; Koloczek, Alexander; Sonnabend, Kerstin; Travaglio, Claudia; Weigand, Mario
2015-05-01
Neutron capture cross sections of unstable isotopes are important for neutron-induced nucleosynthesis as well as for technological applications. A combination of a radioactive beam facility, an ion storage ring and a high flux reactor would allow a direct measurement of neutron induced reactions over a wide energy range on isotopes with half lives down to minutes. The idea is to measure neutron-induced reactions on radioactive ions in inverse kinematics. This means, the radioactive ions will pass through a neutron target. In order to efficiently use the rare nuclides as well as to enhance the luminosity, the exotic nuclides can be stored in an ion storage ring. The neutron target can be the core of a research reactor, where one of the central fuel elements is replaced by the evacuated beam pipe of the storage ring. Using particle detectors and Schottky spectroscopy, most of the important neutron-induced reactions, such as (n,?), (n,p), (n,?), (n,2n), or (n,f), could be investigated.
René Reifarth; Yuri A. Litvinov; Anne Endres; Kathrin Göbel; Tanja Heftrich; Jan Glorius; Alexander Koloczek; Kerstin Sonnabend; Claudia Travaglio; Mario Weigand
2015-07-12
Neutron capture cross sections of unstable isotopes are important for neutron-induced nucleosynthesis as well as for technological applications. A combination of a radioactive beam facility, an ion storage ring and a high flux reactor would allow a direct measurement of neutron induced reactions over a wide energy range on isotopes with half lives down to minutes. The idea is to measure neutron-induced reactions on radioactive ions in inverse kinematics. This means, the radioactive ions will pass through a neutron target. In order to efficiently use the rare nuclides as well as to enhance the luminosity, the exotic nuclides can be stored in an ion storage ring. The neutron target can be the core of a research reactor, where one of the central fuel elements is replaced by the evacuated beam pipe of the storage ring. Using particle detectors and Schottky spectroscopy, most of the important neutron-induced reactions, such as (n,$\\gamma$), (n,p), (n,$\\alpha$), (n,2n), or (n,f), could be investigated.
NASA Astrophysics Data System (ADS)
Pain, S. D.; Cizewski, J. A.; Hatarik, R.; Jones, K. L.; Thomas, J. S.; Bardayan, D. W.; Blackmon, J. C.; Nesaraja, C. D.; Smith, M. S.; Kozub, R. L.; Johnson, M. S.
2007-08-01
The development of high quality radioactive beams, such as those at the HRIBF at Oak Ridge National Laboratory, has made possible the measurement of transfer reactions in inverse kinematics on unstable nuclei. Measurement of (d,p) reactions on neutron-rich nuclei yield data on the evolution of nuclear structure away from stability, and are of astrophysical interest due to the proximity of suggested nuclear burning paths in the astrophysical r-process in supernovae. Experimentally, (d,p) reactions on heavy (Z = 50) fission fragments are complicated by the strongly inverse kinematics, and the relatively low beam intensities. Consequently, ejectile detection with high resolution in position and energy, a high dynamic range and a high solid angular coverage is required. The Oak Ridge Rutgers University Barrel Array (ORRUBA) is a new silicon detector array currently under construction, optimized for the measurement of (d,p) reactions in inverse kinematics. It consists of two rings of silicon detectors, providing a high solid angular coverage for angles symmetrically forward and backward of 90°. Resistive strip detectors are used to obtain high precision position and energy measurement of reaction ejectiles.
NASA Astrophysics Data System (ADS)
Goldberg, D.; Haase, J. S.; Melgar, D.; Bock, Y.; Geng, J.; Saunders, J. K.
2014-12-01
The seismogeodetic combination of high-rate GPS observables and seismic acceleration captures the broadband on-scale recording of earthquake ground motions. The use of these data for determining rapid centroid moment tensor solutions ("fastCMT") has been demonstrated in the post-analysis of the 2010 Mw 7.2 El Mayor-Cucapah earthquake. This seismogeodetic combination will improve source inversions for future earthquakes, but large-scale accelerometer deployment at the many available permanent GPS stations is limited by the cost of traditional observatory-grade accelerometers. Instead, we improve feasibility by installing SIO Geodetic Modules and low-cost MEMS accelerometers at 17 GPS stations in southern California near the San Andreas, San Jacinto, and Elsinore faults, transmitting data in real time for analysis of seismic velocity and displacement waveforms. We examine the performance of our seismogeodetic subnetwork using the El Mayor-Cucapah earthquake as our focus. We calculate a kinematic slip inversion, using the small set of seismogeodetic waveforms available at the time of the event, and assess the reliability of the result in comparison to the fastCMT solution. We evaluate reliability by using our model to predict ground motion at independent stations, and using recorded data as verification at a range of frequencies. Next we supplement the dataset by including realistic simulated waveforms for the additional 17 seismogeodetic stations, adding realistic seismogeodetic noise, and demonstrate the improved reliability of our result in terms of reducing the space of possible solutions due to better geometric constraints. The MEMS accelerometer has higher noise than the observatory-grade accelerometer, which we quantify using strong motion recordings from a series of UCSD NEES outdoor shaketable experiments conducted in December 2013 and January 2014. Results will provide confidence in the use of the MEMS accelerometer for large-scale deployment as an alternative to an observatory-grade accelerometer, as well as the prospects for the increased station density to improve the source parameters of future events, in particular a large earthquake forecast for the southern San Andreas fault.
Resonant scattering of 22Na + p studied by the thick-target inverse-kinematic method
NASA Astrophysics Data System (ADS)
Jin, S. J.; Wang, Y. B.; Su, J.; Yan, S. Q.; Li, Y. J.; Guo, B.; Li, Z. H.; Zeng, S.; Lian, G.; Bai, X. X.; Liu, W. P.; Yamaguchi, H.; Kubono, S.; Hu, J.; Kahl, D.; Jung, H. S.; Moon, J. Y.; Lee, C. S.; Teranishi, T.; Wang, H. W.; Ishiyama, H.; Iwasa, N.; Komatsubara, T.; Brown, B. A.
2013-09-01
Background: In presolar low-density graphite grains, an extraordinarily large 22Ne/20Ne ratio or even nearly pure 22Ne is found, pointing to the condensation of radioactive 22Na in grains. Supernovae and neon-rich novae are the main events that produce 22Na via the explosive hydrogen burning process. The 22Na(p, ?)23Mg reaction is one of the key reactions that influences the 22Na abundance in ejecta.Purpose:The present work aims to explore the proton resonant states in 23Mg relevant to the astrophysical 22Na(p, ?)23Mg reaction. The determined 23Mg resonant parameters can be used to evaluate the 22Na(p, ?)23Mg reaction rate.Method:A low-energy 22Na radioactive ion beam is produced via the 1H(22Ne, 22Na)n reaction, and used to measure the experimental excitation function of the 22Na + p resonant scattering with a conventional thick-target inverse kinematic method. R-matrix analysis is applied to deduce the 23Mg resonance parameters from the experimental excitation function.Results: Three proton resonance states in 23Mg are observed. Spins/parities and the proton partial widths are determined. The deduced excitation energies agree with the compiled values.Conclusions: The new spin and parity assignments allow us to perform a shell-model calculation of the ? widths of the 23Mg resonant states for the evaluation of the 22Na(p, ?)23Mg astrophysical reaction rate. The two s-wave resonant states established in this work at 8.793 and 8.916 MeV in 23Mg, respectively, increase the total reaction rate by about 5% at a temperature greater than 2 GK.
R. V. Dubey; J. A. Euler; S. M. Babcock; R. L. Glassell
1988-01-01
A computationally efficient, kinematic optimization scheme is presented for seven-degree-of-freedom robots with spherical wrists. This scheme uses the gradient projection method, and it does not require the generalized inverse of the Jacobian. An efficient formulation for determining joint velocities is obtained. Thus, this control scheme is well-suited for real-time implementation, which is essential if the end-effector trajectory is continuously modified
Computational Development of Jacobian Matrices for Complex Spatial Manipulators
Goehler, Craig M.; Murray, Wendy M.
2012-01-01
Current methods for developing manipulator Jacobian matrices are based on traditional kinematic descriptions such as Denavit and Hartenberg parameters. The resulting symbolic equations for these matrices become cumbersome and computationally inefficient when dealing with more complex spatial manipulators, such as those seen in the field of biomechanics. This paper develops a modified method for Jacobian development based on generalized kinematic equations that incorporates partial derivatives of matrices with Leibniz’s Law (the product rule). It is shown that a set of symbolic matrix functions can be derived that improve computational efficiency when used in MATLAB® M-Files and are applicable to any spatial manipulator. An articulated arm subassembly and a musculoskeletal model of the hand are used as examples. PMID:22442500
NASA Astrophysics Data System (ADS)
Kneller, Erik A.; Johnson, Christopher A.; Karner, Garry D.; Einhorn, Jesse; Queffelec, Thomas A.
2012-12-01
Published plate reconstructions commonly show significant differences in initial plate configuration and syn-extensional opening directions. The variability of published models is primarily due to the difficulty associated with restoring crustal stretching history. Here we present an inverse non-rigid kinematic method that inverts plate motion and present day crustal thickness to approximate the history of bulk lateral strain and crustal thinning associated with lithospheric stretching. The kinematic link between plate motion and bulk crustal thickness that is used with this method is based on insights obtained from geodynamic models. We implement this approach in open source kinematic modeling software and apply it to test new Early Mesozoic plate kinematic models of the Central Atlantic. This application shows that the patterns of stretching inferred from the syn-rift basins of the Newark Supergroup can be explained if (1) syn-rift Euler pole flow lines were parallel to the Grand Banks transform margin and (2) initial formation of the East Coast Margin Igneous Province was coincident with the formation of the Central Atlantic Magmatic Province. These syn-rift to breakup models of the Central Atlantic lead to better constrained models of early seafloor spreading that show full spreading velocities in the ultraslow regime and within the transition from ultraslow to slow spreading regimes.
Development of a kinematically focused neutron source with the p(7Li,n)7Be inverse reaction
NASA Astrophysics Data System (ADS)
Lebois, M.; Wilson, J. N.; Halipré, P.; Leniau, B.; Matea, I.; Oberstedt, A.; Oberstedt, S.; Verney, D.
2014-01-01
Directional beams of neutrons can be produced, if a nuclear reaction, which emits neutrons, is initiated in inverse kinematics with a heavy ion projectile bombarding a light target. In this paper we investigate the use of the p(7Li,n)7Be inverse reaction to produce kinematically focused, quasi-mono-energetic neutron beams with a view to develop such an unusual neutron source for fundamental and applied nuclear physics studies. An experiment was carried out to validate the concept and to test the viability of two types of hydrogen-rich solid targets: polypropylene and TiH2. Neutron time-of-flight/energy spectra at 3 m distance from the source have been measured at 7Li bombarding energies of 13.5, 15, 15.5, 16, and 17 MeV, and neutron backgrounds from parasitic reactions have been characterized. The neutron angular distribution in the laboratory has been measured at 15 MeV. A Monte-Carlo code based on two-body relativistic kinematics has been developed and validated by comparison with the experimental data. Code-based extrapolations have then been used to deduce neutron energy spectra and maximum neutron fluxes available for future irradiation of samples placed in the neutron beam at small distances. For neutrons produced with thin (4 ?m) and thick (28 ?m) polypropylene targets the maximum available fluxes are calculated to be 107n/s/sr and 7×107 n/s/sr respectively. The development of a dedicated facility to produce kinematically focused neutrons is discussed.
NASA Astrophysics Data System (ADS)
Wang, Lejing; Zou, Rui; Weidert, Simon; Landes, Juergen; Euler, Ekkehard; Burschka, Darius; Navab, Nassir
2011-03-01
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.
Solving the Differential Biochemical Jacobian from Metabolomics Covariance Data
Nägele, Thomas; Mair, Andrea; Sun, Xiaoliang; Fragner, Lena; Teige, Markus; Weckwerth, Wolfram
2014-01-01
High-throughput molecular analysis has become an integral part in organismal systems biology. In contrast, due to a missing systematic linkage of the data with functional and predictive theoretical models of the underlying metabolic network the understanding of the resulting complex data sets is lacking far behind. Here, we present a biomathematical method addressing this problem by using metabolomics data for the inverse calculation of a biochemical Jacobian matrix, thereby linking computer-based genome-scale metabolic reconstruction and in vivo metabolic dynamics. The incongruity of metabolome coverage by typical metabolite profiling approaches and genome-scale metabolic reconstruction was solved by the design of superpathways to define a metabolic interaction matrix. A differential biochemical Jacobian was calculated using an approach which links this metabolic interaction matrix and the covariance of metabolomics data satisfying a Lyapunov equation. The predictions of the differential Jacobian from real metabolomic data were found to be correct by testing the corresponding enzymatic activities. Moreover it is demonstrated that the predictions of the biochemical Jacobian matrix allow for the design of parameter optimization strategies for ODE-based kinetic models of the system. The presented concept combines dynamic modelling strategies with large-scale steady state profiling approaches without the explicit knowledge of individual kinetic parameters. In summary, the presented strategy allows for the identification of regulatory key processes in the biochemical network directly from metabolomics data and is a fundamental achievement for the functional interpretation of metabolomics data. PMID:24695071
NASA Technical Reports Server (NTRS)
Williams, Robert L., II
1992-01-01
The forward position and velocity kinematics for the redundant eight-degree-of-freedom Advanced Research Manipulator 2 (ARM2) are presented. Inverse position and velocity kinematic solutions are also presented. The approach in this paper is to specify two of the unknowns and solve for the remaining six unknowns. Two unknowns can be specified with two restrictions. First, the elbow joint angle and rate cannot be specified because they are known from the end-effector position and velocity. Second, one unknown must be specified from the four-jointed wrist, and the second from joints that translate the wrist, elbow joint excluded. There are eight solutions to the inverse position problem. The inverse velocity solution is unique, assuming the Jacobian matrix is not singular. A discussion of singularities is based on specifying two joint rates and analyzing the reduced Jacobian matrix. When this matrix is singular, the generalized inverse may be used as an alternate solution. Computer simulations were developed to verify the equations. Examples demonstrate agreement between forward and inverse solutions.
Inverse Kinematics for a Point-Foot Quadruped Robot with Dynamic Redundancy Resolution
Alexander C. Shkolnik; Russ Tedrake
2007-01-01
In this work we examine the control of center of mass and swing leg trajectories in LittleDog, a point-foot quadruped robot. It is not clear how to formulate a function to compute forward kinematics of the center of mass of the robot as a function of actuated joint angles because point-foot walkers have no direct actuation between the feet and
A new approach to solve inverse kinematics of a planar flexible continuum robot
NASA Astrophysics Data System (ADS)
Amouri, Ammar; Mahfoudi, Chawki; Zaatri, Abdelouahab; Merabti, Halim
2014-10-01
Research on the modeling of continuum robots, focused on ways to constrain the geometrical models, while maintaining maximum specificities and mechanical properties of the robot. In this paper we propose a new numerical solution for solving the inverse geometric model of a planar flexible continuum robot, we assuming that each section is curved in an arc of a circle, while having the central axis of the inextensible structure. The inverse geometric model for one section is calculated geometrically, whereas the extreme points, of each section, used in calculating the inverse geometric model for multi-section is calculated numerically using a particle swarm optimization (PSO) method. Simulation examples of this method are carried to validate the proposed approach.
Measurement of the 8He(p,n)8Li Reaction at Intermediate Energy in Inverse Kinematics
NASA Astrophysics Data System (ADS)
Kobayashi, Motoki; Yako, Kentaro; Shimoura, Susumu; Dozono, Masanori; Kawase, Shoichiro; Kisamori, Keiichi; Kubota, Yuki; Lee, CheongSoo; Michimasa, Shinichiro; Miya, Hiroyuki; Ota, Shinsuke; Sakai, Hideyuki; Sasano, Masaki; Takaki, Motonobu
We performed the first measurement of the 8He(p,n)8Li reaction at a beam energy of 190A MeV in inverse kinematics at the RIKEN RI Beam Factory in order to study the spin-isospin response of a neutron-rich nucleus 8He. The excitation energy spectrum of the residual 8Li was obtained by tagging the channels decaying to Li isotopes. In addition to a peak which is assigned to the 1+ state at 0.98 MeV, a peak with a large transition strength is observed at around 8 MeV, which is likely to be populated by Gamow-Teller transitions.
Kinematic earthquake source inversion and tsunami runup prediction with regional geophysical data
NASA Astrophysics Data System (ADS)
Melgar, D.; Bock, Y.
2015-05-01
Rapid near-source earthquake source modeling relying only on strong motion data is limited by instrumental offsets and magnitude saturation, adversely affecting subsequent tsunami prediction. Seismogeodetic displacement and velocity waveforms estimated from an optimal combination of high-rate GPS and strong motion data overcome these limitations. Supplementing land-based data with offshore wave measurements by seafloor pressure sensors and GPS-equipped buoys can further improve the image of the earthquake source and prediction of tsunami extent, inundation, and runup. We present a kinematic source model obtained from a retrospective real-time analysis of a heterogeneous data set for the 2011 Mw9.0 Tohoku-Oki, Japan, earthquake. Our model is consistent with conceptual models of subduction zones, exhibiting depth dependent behavior that is quantified through frequency domain analysis of slip rate functions. The stress drop distribution is found to be significantly more correlated with aftershock locations and mechanism types when off-shore data are included. The kinematic model parameters are then used as initial conditions in a fully nonlinear tsunami propagation analysis. Notably, we include the horizontal advection of steeply sloping bathymetric features. Comparison with post-event on-land survey measurements demonstrates that the tsunami's inundation and runup are predicted with considerable accuracy, only limited in scale by the resolution of available topography and bathymetry. We conclude that it is possible to produce credible and rapid, kinematic source models and tsunami predictions within minutes of earthquake onset time for near-source coastal regions most susceptible to loss of life and damage to critical infrastructure, regardless of earthquake magnitude.
Tachi, Susumu
ISMCR2004 A12-Page 1 A Method to Solve Inverse Kinematics of Redundant Slave Arm in The Master-Slave}@star.t.u-tokyo.ac.jp Abstract A master-slave manipulator with different degrees of freedom has some advantages, such as operational performance. However, it is difficult to determine the angles of a redundant slave manipulator
Pin, F.G.; Belmans, P.F.R.; Culioli, J.C.; Carlson, D.D.; Tulloch, F.A.
1994-12-31
A new analytical method to resolve underspecified systems of algebraic equations is presented. The method is referred to as the Full Space Parameterization (FSP) method and utilizes easily- calculated projected solution vectors to generate the entire space of solutions of the underspecified system. Analytic parameterizations for both the space of solutions and the null space of the system reduce the determination of a task-requirement-based single solution to a m {minus} n dimensional problem, where m {minus} n is the degree of underspecification, or degree of redundancy, of the system. An analytical solution is presented to directly calculate the least-norm solution from the parameterized space and the results are compared to solutions of the standard pseudo-inverse algorithm which embodies the (least-norm) Moore-Penrose generalized inverse. Application of the new solution method to a variety of systems and task requirements are discussed and sample results using four-link planar manipulators with one or two degrees of redundancy and a seven degree-of-freedom manipulator with one or four degrees of redundancy are presented to illustrate the efficiency of the new FSP method and algorithm.
Y. X. Su; B. Y. Duan; C. H. Zheng
2001-01-01
This paper presents a methodology for the design of optimal kinematical characteristics of Stewart platform using genetic algorithms (GAs). The optimal kinematics index which expressed by Jacobian matrix of Stewart platform is first deduced, and then the minimum of condition numbers of Jacobian matrix in the whole trajectory tracing workspace is used as the objective function. The constrained optimal design
Jacobian approach to fast acoustic model adaptation
Shigeki Sagayama; Yoshikazu Yamaguchi; Satoshi Takahashi; J. Takahashi
1997-01-01
This paper describes a Jacobian approach to fast adaptation of acoustic models to noisy environments. Acoustic models under a noise assumption are compensated by Jacobian matrices with the difference between assumed and observed noise cepstra. Detailed mathematical formulation and algorithm derivation are presented. Experiments showed that when a small amount of training data is given, this approach outperforms the existing
Spin-isospin response of neutron-rich nucleus 8He via (p,n) reaction in inverse kinematics
NASA Astrophysics Data System (ADS)
Kobayashi, Motoki; Yako, Kentaro; Shimoura, Susumu; Kawase, Shoichiro; Kisamori, Keiichi; Kubota, Yuki; Lee, Cheongsoo; Michimasa, Shin'ichiro; Miya, Hiroyuki; Ota, Shinsuke; Takaki, Motonobu; Dozono, Masanori; Sakai, Hideyuki; Sasano, Masaki; Sharaq06 Collaboration
2014-09-01
We measured the Gamow-Teller (GT) strength of the neutron-rich nucleus 8He, which has the largest neutron-to-proton ratio among all known particle-stable nuclei, to study the spin-isospin response of very neutron-rich nuclei. We performed the first measurement of the 8He (p , n) 8Li reaction at 190 A MeV in inverse kinematics at the RIKEN RI Beam Factory. Recoil neutrons with low kinetic energies were detected by the neutron detector array WINDS, which was recently developed. The residual particle 8Li and its decay product 7Li were detected by auxiliary beam line detectors, a plastic scintillator and a multi-wire drift chamber. We obtained the double differential cross sections at excitation energies up to Ex ~ 20 MeV, where two peaks were observed at ~ 1 MeV and ~ 8 MeV. We evaluated the GT strength for the neutron decay channel of the observed 8-MeV state. The result suggests that most of the GT strength is concentrated in the resonance state at ~ 8 MeV. It was the first direct observation of the GT Resonance of 8He.
NASA Astrophysics Data System (ADS)
Roma, Maria; Pla, Oriol; Butillé, Mireia; Roca, Eduard; Ferrer, Oriol
2015-04-01
The widespread extensional deformation that took place during Jurassic to Cretaceous times in the Western Europe and north-Atlantic realm resulted in the formation of several rift systems. Some of the basins associated to these rifts show broad syncline-shapes filled by thick sedimentary successions deposited overlying a hyperextended crust (i.e., Parentis, Cameros, Organyà or Columbrets basins in Iberia). The development of these syncline basins has been associated to the slip of low-angle lithospheric-scale extensional faults with ramp/flat geometries. The shape and kinematics of such faults have been usually established using the architecture of syn-kinematic layers and assuming a complete coupling of the hangingwall rocks and a layer parallel flexural slip deformation mechanism. However almost all these basins include pre-kinematic Upper Triassic salt layers which undubtoufully acted as an effective detachment decoupling the structure of sub- and suprasalt units. The presence of this salt is denoted by the growth of salt structures as diapirs or salt walls at the edges of these basins where the overburden was thinner. During latest Cretaceous and Cenozoic these basins were partially inverted and often incorporated into thrust-and-fold belts as the Pyrenees . Contractional deformation resulted in the reactivation of major extensional faults and, above the salt, the squeezing of pre-existent salt structures. The pre-kinematic salt clearly acted again as as a major detachment decoupling the contractional deformation. Using an experimental approach (scaled sand-box models) the aim of our research is threefold: 1) to determine the geometrical features of the hangingwall above a convex upwards ramp of a low angle extensional fault with and without pre-kinematic salt, and consequently; 2) to decipher the role played by a pre-kinematic viscous layer, such as salt, in the development of these syncline basins; and 3) to characterize the contractional deformation that took place in them during a later contractional inversion. To achieve this goal an experimental program including seven different sand-box models has been carried out. The experimental results show that fault shape controls the geometry and the kinematic evolution of the ramp synclines formed on the hangingwall during extension and subsequent inversion. Regarding this, the experiments also demonstrate that the presence of a viscous layer changed significantly the kinematic of the basin developing two clearly different structural styles above and below the polymer. The kinematic of this basin during extension change dramatically when the silicone layer was depleted with the formation of primary welds. Since this moment model's kinematic becomes similar to the models without silicone. During the inversion, models show that low shortening produced the contractional reactivation of the major fault arched and uplifted the basin. In this scenario, if salt is rather continuous, took place an incipient reactivation of the silicone layer as a contractional detachment. By contrast, high shortening produces the total inversion of the detachment faults and the pop-up of the extensional basin. Finally, models are compared with different natural analogues from Iberia validating previous published interpretations or proposing new interpretations inferring the geometry of the major fault, specially if the presence of a salt interlayer in the deformed rocks is known or suspected.
ERIC Educational Resources Information Center
Brown, Malcolm
2009-01-01
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…
NSDL National Science Digital Library
2011-01-01
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.
{sup 34}P({sup 7}Li,{sup 7}Be+{gamma}) Reaction at 100A MeV in Inverse Kinematics
Zegers, R. G. T.; Meharchand, R.; Brown, B. A.; Guess, C. J.; Hitt, G. W. [National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824-1321 (United States); Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824 (United States); Joint Institute for Nuclear Astrophysics, Michigan State University, East Lansing, Michigan 48824 (United States); Shimbara, Y.; Bazin, D.; Diget, C. A.; Hausmann, M.; Vaman, C.; Weisshaar, D.; Yurkon, J. [National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824-1321 (United States); Austin, Sam M.; Tur, C. [National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824-1321 (United States); Joint Institute for Nuclear Astrophysics, Michigan State University, East Lansing, Michigan 48824 (United States); Gade, A.; King, M.; Miller, D.; Signoracci, A.; Starosta, K.; Voss, P. [National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824-1321 (United States); Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824 (United States)
2010-05-28
We report on the first successful extraction of a {beta}{sup +} Gamow-Teller strength distribution from a radioactive isotope in an intermediate-energy charge-exchange experiment in inverse kinematics. The ({sup 7}Li,{sup 7}Be+{gamma}(429 keV)) reaction at 100A MeV was used to measure Gamow-Teller transition strengths from {sup 34}P to states in {sup 34}Si. The results show that little mixing occurs between sd and pf shell configurations for the low-lying 0{sup +} and 2{sup +} states even though {sup 34}Si neighbors the island of inversion and low-lying 2({h_bar}/2{pi}){omega} intruder states exist. Shell-model calculations in the sdpf model space are consistent with these findings.
Jacobian for conversion from Euler Angles to Quaternions
Roumeliotis, Stergios I.
Jacobian for conversion from Euler Angles to Quaternions Nikolas Trawny and Stergios Roumeliotis-0572 URL: http://www.cs.umn.edu/~trawny #12;Jacobian for conversion from Euler Angles to Quaternions the Jacobian needed for error conversion when changing from Euler angles to quaternion based attitude
Tropical curves, their Jacobians and Theta functions
Grigory Mikhalkin; Ilia Zharkov
2006-01-01
We study Jacobian varieties for tropical curves. These are real tori equipped with integral affine structure and symmetric bilinear form. We define tropical counterpart of the theta function and establish tropical versions of the Abel-Jacobi, Riemann-Roch and Riemann theta divisor theorems.
A Dexterity Measure for the Kinematic Control of Robot Manipulator with Redundany
Chang, Pyung H.
1988-02-01
We have derived a new performance measure, product of minors of the Jacobian matrix, that tells how far kinematically redundant manipulators are from singularity. It was demonstrated that previously used performance ...
Learning the inverse kinetics of an octopus-like manipulator in three-dimensional space.
Giorelli, M; Renda, F; Calisti, M; Arienti, A; Ferri, G; Laschi, C
2015-06-01
This work addresses the inverse kinematics problem of a bioinspired octopus-like manipulator moving in three-dimensional space. The bioinspired manipulator has a conical soft structure that confers the ability of twirling around objects as a real octopus arm does. Despite the simple design, the soft conical shape manipulator driven by cables is described by nonlinear differential equations, which are difficult to solve analytically. Since exact solutions of the equations are not available, the Jacobian matrix cannot be calculated analytically and the classical iterative methods cannot be used. To overcome the intrinsic problems of methods based on the Jacobian matrix, this paper proposes a neural network learning the inverse kinematics of a soft octopus-like manipulator driven by cables. After the learning phase, a feed-forward neural network is able to represent the relation between manipulator tip positions and forces applied to the cables. Experimental results show that a desired tip position can be achieved in a short time, since heavy computations are avoided, with a degree of accuracy of 8% relative average error with respect to the total arm length. PMID:25970238
Hacker, C.J.; Fries, G.A.; Pin, F.G.
1997-01-01
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.
A Jacobian elliptic single-field inflation
Villanueva, J R
2015-01-01
In the scenario of single-field inflation, this field is done in terms of Jacobian elliptic functions. This approach provides, when constrained to particular cases, analytic solutions already known in the past, generalizing them to a bigger family of analytical solutions. The emergent cosmology is analysed using the Hamilton-Jacobi approach and then, the main results are contrasted with the recent measurements obtained from the Planck 2015 data.
A Jacobian elliptic single-field inflation
NASA Astrophysics Data System (ADS)
Villanueva, J. R.; Gallo, Emanuel
2015-06-01
In the scenario of single-field inflation, this field is described in terms of Jacobian elliptic functions. This approach provides, when constrained to particular cases, analytic solutions already known in the past, generalizing them to a bigger family of analytical solutions. The emergent cosmology is analyzed using the Hamilton-Jacobi approach and then the main results are contrasted with the recent measurements obtained from the Planck 2015 data.
Projectors on the intermediate algebraic Jacobians
Vial, Charles
2009-01-01
Let $X$ be a smooth projective variety over an algebraically closed subfield of $\\C$. Under mild assumption, we construct projectors modulo rational equivalence onto the last step of the coniveau filtration on the cohomology of $X$. We obtain a "motivic" description of the Abel-Jacobi maps to the algebraic part of the intermediate Jacobians. As an application, this enables us to relate the injectivity of the Abel-Jacobi map in all degrees modulo torsion to finite dimensionality for the motive of $X$.
Kinematic programming alternatives for redundant manipulators
John Baillieul
1985-01-01
In the growing literature on redundant manipulator control, a number of techniques have been proposed for solving the inverse kinemetics problem. Some of these techniques are surveyed with a discussion of strengths and weaknesses of each. A new approach, called the extended Jacobian technique, is also presented. It is argued that because this technique may be expected to lift closed
Y. X. Su; B. Y. Duan
2000-01-01
A large Stewart platform for fine tuning of the feed source tracing is presented in this paper. The model of kinematics control is developed with coordinate transformation, and a quasi-static load analysis is made by virtual work principle with Jacobian matrix because the tracing speed is slow. The kinematics accuracy model is derived by position vector analysis, and the kinematics
NASA Astrophysics Data System (ADS)
Lorito, S.; Piatanesi, A.; Cannelli, V.; Romano, F.; Melini, D.
2010-02-01
We (re)analyzed the source of the 26 December 2004 Sumatra-Andaman earthquake and tsunami through a nonlinear joint inversion of an inhomogeneous data set made up of tide gauges, satellite altimetry, and far-field GPS recordings. The purpose is twofold: (1) the retrieval of the main kinematics rupture parameters (slip, rake, and rupture velocity) and (2) the inference of the rigidity of the source zone. We independently estimate the slip from tsunami data and the seismic moment from geodetic data to derive the rigidity. Our results confirm that the source of the 2004 Sumatra-Andaman earthquake has a complex geometry, constituted by three main slip patches, with slip peaking at ˜30 m in the southern part of the source. The rake direction rotates counterclockwise at the northern part of the source, according to the direction of convergence along the trench. The rupture velocity is higher in the deeper than in the shallower part of the source, consistent with the expected increase of rigidity with depth. It is also lower in the northern part, consistent with known variations of the incoming plate properties and shear velocity. Our model features a rigidity (20-30 GPa) that is lower than the preliminary reference Earth model (PREM) average for the seismogenic volume. The source rigidity is one of the factors controlling the tsunami genesis: for a given seismic moment, the lower the rigidity, the higher the induced seafloor displacement. The general consistence between our source model and previous studies supports the effectiveness of our approach to the joint inversion of geodetic and tsunami data for the rigidity estimation.
Learning-based Modified Transpose Jacobian control of robotic manipulators
Mahmood Karimi; S. Moosavian
2008-01-01
The modified transpose Jacobian (MTJ) algorithm has been proposed, based on an approximated feedback linearization approach, in which there is no need to a priori knowledge of the plant dynamics. In this paper, a Learning-based modified transpose Jacobian (LMTJ) control algorithm is presented for trajectory tracking of robotic manipulators in an iterative operation mode. In this new control method, the
What Color Is Your Jacobian? Graph Coloring for Computing Derivatives
Assefaw Hadish Gebremedhin; Fredrik Manne
2005-01-01
Graph coloring has been employed since the 1980s to efficiently compute sparse Jacobian and Hessian matrices using either finite differences or automatic differentiation. Several coloring problems occur in this context, depending on whether the matrix is a Jacobian or a Hessian, and on the specifics of the computational techniques employed. We consider eight variant vertexcoloring problems here. This article begins
NASA Astrophysics Data System (ADS)
Lorito, S.; Piatanesi, A.; Cannelli, V.; Romano, F.; Melini, D.
2009-04-01
We (re)analyzed the causative source of the 26 December 2004 Sumatra-Andaman earthquake and tsunami. We performed nonlinear joint inversion of an in-homogeneous dataset made up of tide-gages, satellite altimetry, and far-field GPS recordings. The purpose is two-fold: (1) the retrieval of the main kinematics rupture parameters (slip, rake, rupture velocity), and (2) the inference of the rigidity of the source zone. Our results confirm the source of the 2004 Sumatra-Andaman earthquake is complex as constituted by three main slip patches, with peaks of slip of ~30 meters. The rake rotates counter-clockwise at North. Our source model features a rigidity (20-30 GPa) that is lower than the Preliminary Reference Earth Model [Dziewonski and Anderson, 1981], and the rupture velocity is lower (2 km/s) for the shallower than for deeper part (3.25 km/s) of the source, and lower (2 km/sec) in the deep Northern part of the source.
Piatanesi, A.; Cirella, A.; Spudich, P.; Cocco, M.
2007-01-01
We present a two-stage nonlinear technique to invert strong motions records and geodetic data to retrieve the rupture history of an earthquake on a finite fault. To account for the actual rupture complexity, the fault parameters are spatially variable peak slip velocity, slip direction, rupture time and risetime. The unknown parameters are given at the nodes of the subfaults, whereas the parameters within a subfault are allowed to vary through a bilinear interpolation of the nodal values. The forward modeling is performed with a discrete wave number technique, whose Green's functions include the complete response of the vertically varying Earth structure. During the first stage, an algorithm based on the heat-bath simulated annealing generates an ensemble of models that efficiently sample the good data-fitting regions of parameter space. In the second stage (appraisal), the algorithm performs a statistical analysis of the model ensemble and computes a weighted mean model and its standard deviation. This technique, rather than simply looking at the best model, extracts the most stable features of the earthquake rupture that are consistent with the data and gives an estimate of the variability of each model parameter. We present some synthetic tests to show the effectiveness of the method and its robustness to uncertainty of the adopted crustal model. Finally, we apply this inverse technique to the well recorded 2000 western Tottori, Japan, earthquake (Mw 6.6); we confirm that the rupture process is characterized by large slip (3-4 m) at very shallow depths but, differently from previous studies, we imaged a new slip patch (2-2.5 m) located deeper, between 14 and 18 km depth. Copyright 2007 by the American Geophysical Union.
Off-diagonal Jacobian support for Nodal BCs
John W. Peterson; David Andrs; Derek R. Gaston; Cody J. Permann; Andrew E. Slaughter
2015-01-01
In this brief note, we describe the implementation of o-diagonal Jacobian computations for nodal boundary conditions in the Multiphysics Object Oriented Simulation Environment (MOOSE) [1] framework. There are presently a number of applications [2{5] based on the MOOSE framework that solve complicated physical systems of partial dierential equations whose boundary conditions are often highly nonlinear. Accurately computing the on- and o-diagonal Jacobian and preconditioner entries associated to these constraints is crucial for enabling ecient numerical solvers in these applications. Two key ingredients are required for properly specifying the Jacobian contributions of nonlinear nodal boundary conditions in MOOSE and nite element codes in general: 1. The ability to zero out entire Jacobian matrix rows after \
Elliptic Fibrations on a Generic Jacobian Kummer Surface
Kumar, Abhinav
We describe all the elliptic fibrations with section on the Kummer surface X of the Jacobian of a very general curve C of genus 2 over an algebraically closed field of characteristic 0, modulo the automorphism group of X ...
Inversion strategies for visco-acoustic waveform inversion
NASA Astrophysics Data System (ADS)
Kamei, R.; Pratt, R. G.
2013-08-01
Visco-acoustic waveform inversion can potentially yield quantitative images of the distribution of both velocity and the attenuation parameters from seismic data. Intrinsic P-wave attenuation has been of particular interest, but has also proven challenging. Frequency-domain inversion allows attenuation and velocity relations to be easily incorporated, and allows a natural multiscale approach. The Laplace-Fourier approach extends this to allow the natural damping of waveforms to enhance early arrivals. Nevertheless, simultaneous inversion of velocity and attenuation leads to significant `cross-talk' between the resulting images, reflecting a lack of parameter resolution and indicating the need for pre-conditioning and regularization of the inverse problem. We analyse the cross-talk issue by partitioning the inversion parameters into two classes; the velocity parameter class, and the attenuation parameter class. Both parameters are defined at a reference frequency, and a dispersion relation is assumed that describes these parameters at any other frequency. We formulate the model gradients at a forward modelling frequency, and convert them to the reference frequency by employing the Jacobian of the coordinate change represented by the dispersion relation. We show that at a given modelling frequency, the Fréchet derivatives corresponding to these two parameter classes differ only by a 90° phase shift, meaning that the magnitudes of resulting model updates will be unscaled, and will not reflect the expected magnitudes in realistic (Q-1 ? 1) media. Due to the lack of scaling, cross-talk will be enhanced by poor subsurface illumination, by errors in kinematics, and by data noise. To solve these issues, we introduce an attenuation scaling term (the inverse of a penalty term) that is used to pre-condition the gradient by controlling the magnitudes of the updates to the attenuation parameters. Initial results from a suite of synthetic cross-hole tests using a three-layer randomly heterogenous model with both intrinsic and extrinsic (scattering) attenuation demonstrate that cross-talk is a significant problem in attenuation inversion. Using the same model, we further show that cross-talk can be suppressed by varying the attenuation scaling term in our pre-conditioning operator. This strategy is effective for simultaneous inversion of velocity and attenuation, and for sequential inversion (a two-stage approach in which only the velocity models are recovered in the first stage). Further regularization using a smoothing term applied to the attenuation parameters is also effective in reducing cross-talk, which is often highly oscillatory. The sequential inversion approach restricts the search space for attenuation parameters, and appears to be important in retrieving a reliable attenuation model when strong time-damping is applied. In a final test with our synthetic model, we successfully carry out visco-acoustic inversions of noise-contaminated data.
A modal approach to hyper-redundant manipulator kinematics
Gregory S. Chirikjian; Joel W. Burdick
1994-01-01
This paper presents novel and efficient kinematic modeling techniques for hyper-redundant'' robots. This approach is based on a backbone curve'' that captures the robot's macroscopic geometric features. The inverse kinematic, or hyper-redundancy resolution,'' problem reduces to determining the time varying backbone curve behavior. To efficiently solve the inverse kinematics problem, the authors introduce a modal'' approach, in which a set
Kügler, Philipp; Yang, Wei
2014-06-01
Model building of biochemical reaction networks typically involves experiments in which changes in the behavior due to natural or experimental perturbations are observed. Computational models of reaction networks are also used in a systems biology approach to study how transitions from a healthy to a diseased state result from changes in genetic or environmental conditions. In this paper we consider the nonlinear inverse problem of inferring information about the Jacobian of a Langevin type network model from covariance data of steady state concentrations associated to two different experimental conditions. Under idealized assumptions on the Langevin fluctuation matrices we prove that relative alterations in the network Jacobian can be uniquely identified when comparing the two data sets. Based on this result and the premise that alteration is locally confined to separable parts due to network modularity we suggest a computational approach using hybrid stochastic-deterministic optimization for the detection of perturbations in the network Jacobian using the sparsity promoting effect of [Formula: see text]-penalization. Our approach is illustrated by means of published metabolomic and signaling reaction networks. PMID:23708492
THE MINIMUM AND MAXIMUM NUMBER OF RATIONAL POINTS ON JACOBIAN SURFACES OVER FINITE FIELDS
Paris-Sud XI, Université de
THE MINIMUM AND MAXIMUM NUMBER OF RATIONAL POINTS ON JACOBIAN SURFACES OVER FINITE FIELDS SAFIA HALOUI Abstract. We give some bounds on the numbers of rational points on abelian varieties and jacobians of rational points on jacobians varieties of dimension 2. 1. Introduction We are interested in the number
COLORINGS FOR MORE EFFICIENT COMPUTATION OF JACOBIAN MATRICES
DANIEL WESLEY CRANSTON
Abstract Many methods for computing,Jacobians (such as automatic differentiation and finite difference methods) can be made more efficient given colorings of the lattice points of the plane, cylinder, or torus that assign different colors to all vertices within some specified stencil. We give colorings for the 4l,3 -point star and the l l square stencils (for all l) in the
Exploring Strange Nonchaotic Attractors through Jacobian Elliptic Functions
ERIC Educational Resources Information Center
Garcia-Hoz, A. Martinez; Chacon, R.
2011-01-01
We demonstrate the effectiveness of Jacobian elliptic functions (JEFs) for inquiring into the reshaping effect of quasiperiodic forces in nonlinear nonautonomous systems exhibiting strange nonchaotic attractors (SNAs). Specifically, we characterize analytically and numerically some reshaping-induced transitions starting from SNAs in the context of…
Jacobian, manipulability, condition number and accuracy of parallel robots
Boyer, Edmond
variables vector . The twist W of the end effector is composed of its translational and angular velocities as there is no representation of the orientation whose derivatives corresponds to the angular velocities. However there existsJacobian, manipulability, condition number and accuracy of parallel robots J-P. Merlet INRIA, BP 93
QUASIHOMOGENEITY OF CURVES AND THE JACOBIAN ENDOMORPHISM RING
Schulze, Mathias
QUASIHOMOGENEITY OF CURVES AND THE JACOBIAN ENDOMORPHISM RING MICHEL GRANGER AND MATHIAS SCHULZE is obtained by repeatedly replacing A by the endomorphism ring EndA(J-1 A ) = (JAJ-1 A )-1 . Not much is known by this operation we consider the length X := (EndA(J-1 A )/A). Smoothness of X is equivalent to X = 0
Classical Integrable Systems and Billiards Related to Generalized Jacobians
Yu. Fedorov
1999-01-01
We study some classical integrable systems of dynamics (the Euler top in space, the asymptotic geodesic motion on an ellipsoid) which are linearized on unramified coverings of generalized Jacobian varieties. We find explicit expressions for so called root functions living on such coverings which enable us to solve the problems in terms of generalized theta-functions. In addition, general and asymptotic
Analytical Jacobian Calculation in RT Model Including Polarization Effect
NASA Astrophysics Data System (ADS)
Okabayashi, Y.; Yoshida, Y.; Ota, Y.
2014-12-01
The greenhouse gas observing satellite "GOSAT" launched in January 2009 has been observing global distribution of CO2 and CH4. The TANSO-FTS mounted on GOSAT measures the two polarized components (called "P" and "S") of short wavelength infrared (SWIR) spectrum reflected from the earth's surface. In NIES, column-averaged dry air mole fraction of CO2 and CH4 (XCO2 and XCH4) are retrieved from SWIR spectra. However, the observed polarization information is not effectively utilized in the retrieval process due to the large computational cost of a vector RT model, instead the polarization synthesized spectra and a scalar RT model are used in the operational processing. An optical path length modification due to aerosol scattering is known as the major error source for XCO2 and XCH4 retrieval from SWIR spectra. Because the aerosol scattering changes polarization state of light, more accurate or additional aerosol information is expected by using the observed polarization spectra effectively in the retrieval process, which improves the retrieval accuracy of XCO2 and XCH4. In addition, for information content analysis, sensitivity analysis and error analysis, Jacobian matrix is important onto retrieval algorithm design before analyses for actual observed data. However, in the case of using RT model including polarization effect in retrieval process, the computational cost of Jacobian matrix calculations in maximum a posteriori retrieval is significantly large. Efficient calculation of analytical Jacobian is necessary. As a first step, we are implementing an analytical Jacobian calculation function to the vector RT model "Pstar". RT scheme of Pstar is based on hybrid method comprising the discrete ordinate and matrix operator methods. The reflection/transmission matrices and source vectors are obtained for each vertical layer through the discrete ordinate solution, and the vertically inhomogeneous system is constructed using the matrix operator method. Because the delta-M truncation method is used in the Pstar to reduce the computational cost, single scattering component correction called TMS method is implemented. Calculation of analytical Jacobian has to be constructed above the RT scheme. We will show the formulation and some results of the analytical Jacobian implementation at the presentation.
NASA Astrophysics Data System (ADS)
Yue, Han; Lay, Thorne; Li, Linyan; Yamazaki, Yoshiki; Cheung, Kwok Fai; Rivera, Luis; Hill, Emma M.; Sieh, Kerry; Kongko, Widjo; Muhari, Abdul
2015-03-01
Tsunami observations have particular importance for resolving shallow offshore slip in finite-fault rupture model inversions for large subduction zone earthquakes. However, validations of amplitude linearity and choice of subfault discretization of tsunami Green's functions are essential when inverting tsunami waveforms. We explore such validations using four tsunami recordings of the 25 October 2010 Mentawai Mw 7.8 tsunami earthquake, jointly inverted with teleseismic body waves and 1 Hz GPS (high-rate GPS) observations. The tsunami observations include near-field and far-field deep water recordings, as well as coastal and island tide gauge recordings. A nonlinear, dispersive modeling code, NEOWAVE, is used to construct tsunami Green's functions from seafloor excitation for the linear inversions, along with performing full-scale calculations of the tsunami for the inverted models. We explore linearity and finiteness effects with respect to slip magnitude, variable rake determination, and subfault dimensions. The linearity assumption is generally robust for the deep water recordings, and wave dispersion from seafloor excitation is important for accurate description of near-field Green's functions. Breakdown of linearity produces substantial misfits for short-wavelength signals in tide gauge recordings with large wave heights. Including the tsunami observations in joint inversions provides improved resolution of near-trench slip compared with inversions of only seismic and geodetic data. Two rupture models, with fine-grid (15 km) and coarse-grid (30 km) spacing, are inverted for the Mentawai event. Stronger regularization is required for the fine model representation. Both models indicate a shallow concentration of large slip near the trench with peak slip of ~15 m. Fully nonlinear forward modeling of tsunami waveforms confirms the validity of these two models for matching the tsunami recordings along with the other data.
Luanjing Guo; Hai Huang; Derek Gaston; Cody Permann; David Andrs; George Redden; Chuan Lu; Don Fox; Yoshiko Fujita
2013-03-01
Modeling large multicomponent reactive transport systems in porous media is particularly challenging when the governing partial differential algebraic equations (PDAEs) are highly nonlinear and tightly coupled due to complex nonlinear reactions and strong solution-media interactions. Here we present a preconditioned Jacobian-Free Newton-Krylov (JFNK) solution approach to solve the governing PDAEs in a fully coupled and fully implicit manner. A well-known advantage of the JFNK method is that it does not require explicitly computing and storing the Jacobian matrix during Newton nonlinear iterations. Our approach further enhances the JFNK method by utilizing physics-based, block preconditioning and a multigrid algorithm for efficient inversion of the preconditioner. This preconditioning strategy accounts for self- and optionally, cross-coupling between primary variables using diagonal and off-diagonal blocks of an approximate Jacobian, respectively. Numerical results are presented demonstrating the efficiency and massive scalability of the solution strategy for reactive transport problems involving strong solution-mineral interactions and fast kinetics. We found that the physics-based, block preconditioner significantly decreases the number of linear iterations, directly reducing computational cost; and the strongly scalable algebraic multigrid algorithm for approximate inversion of the preconditioner leads to excellent parallel scaling performance.
43. Kinematics 1 43. KINEMATICS
43. Kinematics 1 43. KINEMATICS Revised January 2000 by J.D. Jackson (LBNL) and June 2008 by D the particles. In the frame where one particle (of mass m2) is at rest (lab frame), Ecm = (m2 1 + m2 2 + 2E1 lab m2)1/2 . (43.3) The velocity of the center-of-mass in the lab frame is cm = plab/(E1 lab + m2) , (43
39. Kinematics 1 39. KINEMATICS
39. Kinematics 1 39. KINEMATICS Revised January 2000 by J.D. Jackson (LBNL) and June 2008 by D the particles. In the frame where one particle (of mass m2) is at rest (lab frame), Ecm = (m2 1 + m2 2 + 2E1 lab m2)1/2 . (39.3) The velocity of the center-of-mass in the lab frame is cm = plab/(E1 lab + m2) , (39
Endomorphism rings of certain Jacobians in finite characteristic
Zarkhin, Yu G [Institute of Mathematical Problems of Biology, Russian Academy of Sciences, Pushchino, Moscow region (Russian Federation)
2002-08-31
We prove that, under certain additional assumptions, the endomorphism ring of the Jacobian of a curve y{sup l}=f(x) contains a maximal commutative subring isomorphic to the ring of algebraic integers of the lth cyclotomic field. Here l is an odd prime dividing the degree n of the polynomial f and different from the characteristic of the algebraically closed ground field; moreover, n{>=}9. The additional assumptions stipulate that all coefficients of f lie in some subfield K over which its (the polynomial's) Galois group coincides with either the full symmetric group S{sub n} or with the alternating group A{sub n}.
Luanjing Guo; Chuan Lu; Hai Huang; Derek R. Gaston
2012-06-01
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.
NASA Astrophysics Data System (ADS)
Hoffmann, V.-E.; Dunkl, I.; von Eynatten, H.; Jähne, F.; Voigt, T.; Kley, J.
2009-04-01
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.
Prejean, S.; Ellsworth, W.; Zoback, M.; Waldhauser, F.
2002-01-01
We have determined high-resolution hypocenters for 45,000+ earthquakes that occurred between 1980 and 2000 in the Long Valley caldera area using a double-difference earthquake location algorithm and routinely determined arrival times. The locations reveal numerous discrete fault planes in the southern caldera and adjacent Sierra Nevada block (SNB). Intracaldera faults include a series of east/west-striking right-lateral strike-slip faults beneath the caldera's south moat and a series of more northerly striking strike-slip/normal faults beneath the caldera's resurgent dome. Seismicity in the SNB south of the caldera is confined to a crustal block bounded on the west by an east-dipping oblique normal fault and on the east by the Hilton Creek fault. Two NE-striking left-lateral strike-slip faults are responsible for most seismicity within this block. To understand better the stresses driving seismicity, we performed stress inversions using focal mechanisms with 50 or more first motions. This analysis reveals that the least principal stress direction systematically rotates across the studied region, from NE to SW in the caldera's south moat to WNW-ESE in Round Valley, 25 km to the SE. Because WNW-ESE extension is characteristic of the western boundary of the Basin and Range province, caldera area stresses appear to be locally perturbed. This stress perturbation does not seem to result from magma chamber inflation but may be related to the significant (???20 km) left step in the locus of extension along the Sierra Nevada/Basin and Range province boundary. This implies that regional-scale tectonic processes are driving seismic deformation in the Long Valley caldera.
The sensor-control Jacobian as a basis for controlling calibration-free robots
Volker Graefe; André Maryniak
1998-01-01
A method for controlling the motions of robots is presented. It is based on the newly introduced sensor-control Jacobian matrix and avoids all quantitative modeling of the robot and the sensor system. The sensor-control Jacobian contains the coefficients that relate those changes in sensor data which are caused by a motion of the robot to the robot control words that
Kinematics and singularity analysis of a 3DOF parallel kinematic machine
F. Zhang; D. Zhang; Jianguo Yang; Beizhi Li
2005-01-01
In this paper, a 3-DOF parallel mechanism that can be used for 3-axis machine tool is introduced. The geometric structure is presented first. Then the inverse kinematic and forward kinematic problems for this structure are solved, the results are validated as well. Screw theory is applied in the paper in order to conduct the singularity analysis. The rational of using
Kinematics and control of redundant robotic arm based on dielectric elastomer actuators
NASA Astrophysics Data System (ADS)
Branz, Francesco; Antonello, Andrea; Carron, Andrea; Carli, Ruggero; Francesconi, Alessandro
2015-04-01
Soft robotics is a promising field and its application to space mechanisms could represent a breakthrough in space technologies by enabling new operative scenarios (e.g. soft manipulators, capture systems). Dielectric Elastomers Actuators have been under deep study for a number of years and have shown several advantages that could be of key importance for space applications. Among such advantages the most notable are high conversion efficiency, distributed actuation, self-sensing capability, multi-degree-of-freedom design, light weight and low cost. The big potentialities of double cone actuators have been proven in terms of good performances (i.e. stroke and force/torque), ease of manufacturing and durability. In this work the kinematic, dynamic and control design of a two-joint redundant robotic arm is presented. Two double cone actuators are assembled in series to form a two-link design. Each joint has two degrees of freedom (one rotational and one translational) for a total of four. The arm is designed to move in a 2-D environment (i.e. the horizontal plane) with 4 DoF, consequently having two degrees of redundancy. The redundancy is exploited in order to minimize the joint loads. The kinematic design with redundant Jacobian inversion is presented. The selected control algorithm is described along with the results of a number of dynamic simulations that have been executed for performance verification. Finally, an experimental setup is presented based on a flexible structure that counteracts gravity during testing in order to better emulate future zero-gravity applications.
Hicks, H.R.; Dory, R.A.; Holmes, J.A.
1983-01-01
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.
Solving Nonlinear Solid Mechanics Problems with the Jacobian-Free Newton Krylov Method
J. D. Hales; S. R. Novascone; R. L. Williamson; D. R. Gaston; M. R. Tonks
2012-06-01
The solution of the equations governing solid mechanics is often obtained via Newton's method. This approach can be problematic if the determination, storage, or solution cost associated with the Jacobian is high. These challenges are magnified for multiphysics applications with many coupled variables. Jacobian-free Newton-Krylov (JFNK) methods avoid many of the difficulties associated with the Jacobian by using a finite difference approximation. BISON is a parallel, object-oriented, nonlinear solid mechanics and multiphysics application that leverages JFNK methods. We overview JFNK, outline the capabilities of BISON, and demonstrate the effectiveness of JFNK for solid mechanics and solid mechanics coupled to other PDEs using a series of demonstration problems.
Low-rank Quasi-Newton updates for Robust Jacobian lagging in Newton methods
Brown, J.; Brune, P. [Mathematics and Computer Science Division, Argonne National Laboratory, 9700 S. Cass Ave., Argonne, IL 60439 (United States)
2013-07-01
Newton-Krylov methods are standard tools for solving nonlinear problems. A common approach is to 'lag' the Jacobian when assembly or preconditioner setup is computationally expensive, in exchange for some degradation in the convergence rate and robustness. We show that this degradation may be partially mitigated by using the lagged Jacobian as an initial operator in a quasi-Newton method, which applies unassembled low-rank updates to the Jacobian until the next full reassembly. We demonstrate the effectiveness of this technique on problems in glaciology and elasticity. (authors)
Magnetotelluric inversion via reverse time migration algorithm of seismic data
Ha, Taeyoung [Department of Mathematical Sciences, Seoul National University, San 56-1, Sillim-dong, Gwanak-gu, Seoul 151-747 (Korea, Republic of)]. E-mail: tyha@math.snu.ac.kr; Shin, Changsoo [School of Civil, Urban and Geosystem Engineering, Seoul National University, San 56-1, Sillim-dong, Gwanak-gu, Seoul 151-742 (Korea, Republic of)]. E-mail: css@model.snu.ac.kr
2007-07-01
We propose a new algorithm for two-dimensional magnetotelluric (MT) inversion. Our algorithm is an MT inversion based on the steepest descent method, borrowed from the backpropagation technique of seismic inversion or reverse time migration, introduced in the middle 1980s by Lailly and Tarantola. The steepest descent direction can be calculated efficiently by using the symmetry of numerical Green's function derived from a mixed finite element method proposed by Nedelec for Maxwell's equation, without calculating the Jacobian matrix explicitly. We construct three different objective functions by taking the logarithm of the complex apparent resistivity as introduced in the recent waveform inversion algorithm by Shin and Min. These objective functions can be naturally separated into amplitude inversion, phase inversion and simultaneous inversion. We demonstrate our algorithm by showing three inversion results for synthetic data.
Kinematics in four-dimensional atmospheric guidance
Ilie Stiharu-Alexe; Carl Dionne; Marc Nolette
1997-01-01
The four-dimensional (4D) atmospheric guidance depict another point of view into the modern autopilot design. This type of guidance assures the tracking, with a pre-specified error, of a desired 4D trajectory. In this paper the 4D kinematics is analyzed, for the case of classical atmospheric vehicles control, in order to develop powerful guidance controllers. The solution of the inverse kinematics
Kinematic functions for the 7 DOF robotics research arm
NASA Technical Reports Server (NTRS)
Kreutz, K.; Long, M.; Seraji, Homayoun
1989-01-01
The Robotics Research Model K-1207 manipulator is a redundant 7R serial link arm with offsets at all joints. To uniquely determine joint angles for a given end-effector configuration, the redundancy is parameterized by a scalar variable which corresponds to the angle between the manipulator elbow plane and the vertical plane. The forward kinematic mappings from joint-space to end-effector configuration and elbow angle, and the augmented Jacobian matrix which gives end-effector and elbow angle rates as a function of joint rates, are also derived.
Fatigue Exploitation in an Inverse Kinematics Framework
Rodríguez, Inmaculada
model to be applied to an articulated figure representing a human body so that it is an adequate is solved and the process repeated until the system converges to a solution. The control of human postures in such a way that fatigue evolution over time can be exploited. Fatigue is then applied to postures
Jacobian Adaptation of HMM with Initial Model Selection for Noisy Speech Recognition
Shimodaira, Hiroshi; Kato, Yukata; Akae, Toshihiko; Nakai, Mitsuru; Sagayama, Shigeki
An extension of Jacobian Adaptation (JA) of HMMs for degraded speech recognition is presented in which appropriate set of initial models is selected from a number of initial-model sets designed for different noise environments. Based on the first...
Nakamura, Kunio; Guizard, Nicolas; Fonov, Vladimir S.; Narayanan, Sridar; Collins, D. Louis; Arnold, Douglas L.
2013-01-01
Gray matter atrophy provides important insights into neurodegeneration in multiple sclerosis (MS) and can be used as a marker of neuroprotection in clinical trials. Jacobian integration is a method for measuring volume change that uses integration of the local Jacobian determinants of the nonlinear deformation field registering two images, and is a promising tool for measuring gray matter atrophy. Our main objective was to compare the statistical power of the Jacobian integration method to commonly used methods in terms of the sample size required to detect a treatment effect on gray matter atrophy. We used multi-center longitudinal data from relapsing–remitting MS patients and evaluated combinations of cross-sectional and longitudinal pre-processing with SIENAX/FSL, SPM, and FreeSurfer, as well as the Jacobian integration method. The Jacobian integration method outperformed these other commonly used methods, reducing the required sample size by a factor of 4–5. The results demonstrate the advantage of using the Jacobian integration method to assess neuroprotection in MS clinical trials. PMID:24266007
Hybrid Motion Control combining Inverse Kinematics and Inverse Dynamics Controllers
Paris-Sud XI, Université de
Rennes I, France Abstract Virtual characters playing in a realistic way virtual musical instruments need of the instrument to his actions and the resulting sound. Transposing these real-world experiences into virtual with virtual musical instruments. This paper proposes a physics-based framework in which a virtual character
A Framework to Illustrate Kinematic Behavior of Mechanisms by Haptic Feedback
Zhang, Qinqin; Bennis, Fouad; Zhang, Wei
2007-01-01
The kinematic properties of mechanisms are well known by the researchers and teachers. The theory based on the study of Jacobian matrices allows us to explain, for example, the singular configuration. However, in many cases, the physical sense of such properties is difficult to explain to students. The aim of this article is to use haptic feedback to render to the user the signification of different kinematic indices. The framework uses a Phantom Omni and a serial and parallel mechanism with two degrees of freedom. The end-effector of both mechanisms can be moved either by classical mouse, or Phantom Omni with or without feedback.
REDBACK: opensource software for efficient noisereduction in plate kinematic reconstructions
Bodin, Thomas
kinematics inferred from hightemporalresolution finiterotation data sets. We describe REDBACK, an opensourceREDBACK: opensource software for efficient noisereduction in plate kinematic reconstructions G University, as part of the AuScopeAGOS Inversion Labora- tory. REDBACK is released opensource under the GNU
Study of the Jacobian of an extended Kalman filter for soil analysis in SURFEXv5
NASA Astrophysics Data System (ADS)
Duerinckx, A.; Hamdi, R.; Mahfouf, J.-F.; Termonia, P.
2015-03-01
An externalised surface scheme like SURFEX allows computationally cheap offline runs. This is a major advantage for surface assimilation techniques such as the extended Kalman filter (EKF), where the offline runs allow a cheaper numerical estimation of the observation operator Jacobian. In the recent past an EKF has been developed within SURFEX for the initialisation of soil water content and soil temperature based on screen-level temperature and relative humidity observations. In this paper we make a comparison of the Jacobian calculated with offline SURFEX runs and with runs coupled to the atmospheric ALARO model. Comparisons are made with respect to spatial structure and average value of the Jacobian, gain values and increments. We determine the optimal perturbation size of the Jacobian for the offline and coupled approaches and compare the linearity of the Jacobian for these cases. Results show that the offline Jacobian approach gives similar results to the coupled approach and that it allows for smaller perturbation sizes that better approximate this linearity assumption. We document a new case of non-linearities that can hamper this linearity assumption and cause spurious 2? t oscillations in small parts of the domain for the coupled as well as offline runs. While these oscillations do not have a detrimental effect on the model run, they can introduce some noise in the Jacobian at the affected locations. The oscillations influence both the surface fluxes and the screen-level variables. The oscillations occur in the late afternoon in summer when a stable boundary layer starts to form near the surface. We propose a filter to remove the oscillations and show that this filter works accordingly.
A hybrid strategy to solve the forward kinematics problem in parallel manipulators
Pratik J. Parikh; Sarah S. Y. Lam
2005-01-01
A parallel manipulator is a closed kinematic structure with the necessary rigidity to provide a high payload to self-weight ratio suitable for many applications in manufacturing, flight simulation systems, and medical robotics. Because of its closed structure, the kinematic control of such a mechanism is difficult. The inverse kinematics problem for such manipulators has a mathematical solution; however, the forward
A new family Jacobian solver for global three-dimensional modeling of atmospheric chemistry
Xuepeng Zhao; Richard P. Turco; Mei Shen
1999-01-01
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
Flux Jacobian matrices and generaled Roe average for an equilibrium real gas
NASA Technical Reports Server (NTRS)
Vinokur, Marcel
1988-01-01
Inviscid flux Jacobian matrices and their properties used in numerical solutions of conservation laws are extended to general, equilibrium gas laws. Exact and approximate generalizations of the Roe average are presented. Results are given for one-dimensional flow, and then extended to three-dimensional flow with time-varying grids.
Derivation of the regularized chiral Jacobian using the zeta function method
Wang, R.
1988-10-01
Using the zeta function method, a general formula for the regularized chiral Jacobian to theories including non-Hermitian Dirac operators D-script defined in arbitrary even-dimensional Euclidean space is derived. The agreement of this formula with the results obtained in the differential geometric approach is also clarified.
Ventilation from four-dimensional computed tomography: density versus Jacobian methods
NASA Astrophysics Data System (ADS)
Castillo, Richard; Castillo, Edward; Martinez, Josue; Guerrero, Thomas
2010-08-01
Two calculation methods to produce ventilation images from four-dimensional computed tomography (4DCT) acquired without added contrast have been reported. We reported a method to obtain ventilation images using deformable image registration (DIR) and the underlying CT density information. A second method performs the ventilation image calculation from the DIR result alone, using the Jacobian determinant of the deformation field to estimate the local volume changes resulting from ventilation. For each of these two approaches, there are variations on their implementation. In this study, two implementations of the Jacobian-based methodology are evaluated, as well as a single density change-based model for calculating the physiologic specific ventilation from 4DCT. In clinical practice, 99mTc-labeled aerosol single photon emission computed tomography (SPECT) is the standard method used to obtain ventilation images in patients. In this study, the distributions of ventilation obtained from the CT-based ventilation image calculation methods are compared with those obtained from the clinical standard SPECT ventilation imaging. Seven patients with 4DCT imaging and standard 99mTc-labeled aerosol SPECT/CT ventilation imaging obtained on the same day as part of a prospective validation study were selected. The results of this work demonstrate the equivalence of the Jacobian-based methodologies for quantifying the specific ventilation on a voxel scale. Additionally, we found that both Jacobian- and density-change-based methods correlate well with global measurements of the resting tidal volume. Finally, correlation with the clinical SPECT was assessed using the Dice similarity coefficient, which showed statistically higher (p-value < 10-4) correlation between density-change-based specific ventilation and the clinical reference than did either Jacobian-based implementation.
NSDL National Science Digital Library
David Smith
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.
Kinematic And Dynamic Simulation Of The 2000 Tottori Japan Earthquake
NASA Astrophysics Data System (ADS)
Francois-Holden, C.; di Carli, S.; Hubans, F.; Madariaga, R.
2005-12-01
We study the kinematic and dynamic rupture propagation of the 2000 Tottori (Japan) earthquake. The earthquake region was well instrumented and provided a good strong motion data set that has been intensively studied. We develop a nonlinear kinematic inversion method based on the neighborhood algorithm which we applied to a set of 30 strong motion recordings located within 40 km of the epicenter. The main purpose of this first step of this study is to compare our results with those from linearised kinematic inversions by Yagi (2001), Sekiguchi (2002) and Semanne et al. (2005). We find several differences that are mainly related to the choice of hypocenter and rupture speed. In a second step, we use the non-linear kinematic source parameters to start a non-linear dynamic inversion. In order to satisfy the dynamic aspects of the rupture we define a rupture scenario where rupture propagation is controlled by the properties of the friction law on the fault. In this study a simple uniform slip-weakening friction law is used everywhere on the fault. From the kinematic slip distribution, we compute the initial stress field on the fault. We then force the beginning of the rupture into an asperity located around the hypocentre of Tottori. Then we determine the initial stress field that leads to a propagation of the rupture that is similar to the kinematics. Several aspects of our kinematic models need to be modified in order to satisfy the generalized Griffith criterion for rupture (from Madariaga and Olsen). The final step is to make a full dynamic inversion using a reduced number of dynamic parameters. For that purpose we project the initial stress field into a limited number of ellipsoidal patches that we parameterize with 5-6 parameters. Using a limited number of such patches we expect to simplify the non-linear inversion method proposed by Peyrat and Olsen.
Kinematic Analysis of the vertebra of an eel like robot
Chablat, Damien
2008-01-01
The kinematic analysis of a spherical wrist with parallel architecture is the object of this article. This study is part of a larger French project, which aims to design and to build an eel like robot to imitate the eel swimming. To implement direct and inverse kinematics on the control law of the prototype, we need to evaluate the workspace without any collisions between the different bodies. The tilt and torsion parameters are used to represent the workspace.
Kinematic modeling for feedback control of an omnidirectional wheeled mobile robot
P. Muir; C. Neuman
1987-01-01
We have introduced a methodology for the kinematic modeling of wheeled mobile robots. In this paper, we apply our methodology to Uranus, an omnidirectional wheeled mobile robot which is being developed in the Robotics Institute of Carnegie Mellon University. We assign coordinate systems to specify the transformation matrices and write the kinematic equations-of-motion. We illustrate the actuated inverse and sensed
Real time kinematic solutions of a non-contacting, three dimensional metrology frame
D. E. Schinstock; J. F. Cuttino
2000-01-01
The forward and the inverse kinematics solutions for a three dimensional, non-contacting metrology system are presented. The solutions are a continuation of earlier works involving the derivation of an error budget for the metrology system; however, the earlier work required iterative methods. The kinematic solutions presented in this paper are closed form, providing real-time feedback and making the system practical
NSDL National Science Digital Library
Moore, Lang
Created by Lang Moore and David Smith for the Connected Curriculum Project, this is a module to review concepts of inverse functions, and to use those concepts, together with functions defined by integrals, to develop inverse trigonometric functions. This is one within a much larger set of learning modules hosted by Duke University.
NASA Astrophysics Data System (ADS)
Sabaapour, Mohammad Reza; Zohoor, Hassan
Swashplate mechanism is the steering control mechanism used in most helicopters. It is a complex multi-loop closed kinematic chain which controls the angles of attack of the main rotor blades. In most new model helicopters, this mechanism is also equipped with the bell-hiller stabilizer bar (flybar), to improve the stability. This paper aimed at the kinematic analysis of one of the latest architectures of the swashplate mechanism, used for hingeless rotor with the flybar. Hence, the position analysis of each module and whole mechanism, based on parallel manipulators concept with more details involved than other works, was presented here. The kinematic model was further developed to obtain Jacobian matrices, velocity and acceleration analysis in detail. Finally, a particular example was conducted and compared with an ADAMS rigid body dynamic model, to verify the analytical model. In many simulated cases, the results matched.
Kinemetry: quantifying kinematic maps
Y. Copin; R. Bacon; M. Bureau; R. L. Davies; E. Emsellem; H. Kuntschner; B. Miller; R. Peletier; E. K. Verolme; P. T. de Zeeuw
2001-09-06
We describe a new technique, kinemetry, to quantify kinematic maps of early-type galaxies in an efficient way. We present the first applications to velocity fields obtained with the integral-field spectrograph SAURON.
Employment of Jacobian elliptic functions for solving problems in nonlinear dynamics of microtubules
Zekovi?, Slobodan; Zdravkovi?, Slobodan; Kavitha, Louis
2012-01-01
We show how Jacobian elliptic functions (JEF) can be used to solve ordinary differential equations (ODE) describing nonlinear dynamics of microtubules (MT). We demonstrate that only one of JEFs can be used while the remaining two do not represent the solutions of the crucial differential equation. We show that a kink-type soliton moves along MT. Beside this solution, we discuss a few more that may or may not have physical meaning. Finally, we show what kinds of ODE can be solved using JEFs.
Assessing the quality of curvilinear coordinate meshes by decomposing the Jacobian matrix
NASA Technical Reports Server (NTRS)
Kerlick, G. D.; Klopfer, G. H.
1982-01-01
An algebraic decomposition of the Jacobian matrix which relates physical and computational variables is presented. This invertible decomposition parameterizes the mesh by the physically intuitive qualities of cell orientation, cell orthogonality, cell volume, and cell aspect ratio. The decomposition can be used to analyze numerically generated curvilinear coordinate meshes and to assess the contribution of the mesh to the truncation error for any specific differential operator and algorithm. This is worked out in detail for Laplace's equation in nonconservative and conservative forms. The analysis is applied to the solution of the full potential code TAIR, showing grid plots, carpet plots, and truncation error for a NACA 0012 airfoil.
Acceleration of k-Eigenvalue / Criticality Calculations using the Jacobian-Free Newton-Krylov Method
Dana Knoll; HyeongKae Park; Chris Newman
2011-02-01
We present a new approach for the $k$--eigenvalue problem using a combination of classical power iteration and the Jacobian--free Newton--Krylov method (JFNK). The method poses the $k$--eigenvalue problem as a fully coupled nonlinear system, which is solved by JFNK with an effective block preconditioning consisting of the power iteration and algebraic multigrid. We demonstrate effectiveness and algorithmic scalability of the method on a 1-D, one group problem and two 2-D two group problems and provide comparison to other efforts using silmilar algorithmic approaches.
A modal approach to hyper-redundant manipulator kinematics
Chirikjian, G.S. (Johns Hopkins Univ., Baltimore, MD (United States). Dept. of Mechanical Engineering); Burdick, J.W. (California Inst. of Tech., Pasadena, CA (United States). School of Engineering and Applied Science)
1994-06-01
This paper presents novel and efficient kinematic modeling techniques for hyper-redundant'' robots. This approach is based on a backbone curve'' that captures the robot's macroscopic geometric features. The inverse kinematic, or hyper-redundancy resolution,'' problem reduces to determining the time varying backbone curve behavior. To efficiently solve the inverse kinematics problem, the authors introduce a modal'' approach, in which a set of intrinsic backbone curve shape functions are restricted to a modal form. The singularities of the modal approach, modal non-degeneracy conditions, and modal switching are considered. For discretely segmented morphologies, the authors introduce fitting'' algorithms that determine the actuator displacements that cause the discrete manipulator to adhere to the backbone curve. These techniques are demonstrated with planar and spatial mechanism examples. They have also been implemented on a 30 degree-of-freedom robot prototype.
Kinematic synthesis of bevel-gear-type robotic wrist mechanisms
NASA Astrophysics Data System (ADS)
Lin, Chen-Chou
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 analysis of platform-type robotic manipulators
NASA Astrophysics Data System (ADS)
Shi, Xiaolun
New methods are developed for the kinematic analysis of serial and platform-type parallel robotic manipulators, including forward and inverse kinematic solutions, singularity identifications and workspace evaluation. Differences between serial and platform-type parallel manipulators, which can provide substantially improved end-point rigidity compared with the conventional serial robotic arms, are addressed. The problem of determining the screw parameters of rigid body motion from initial and final position data is discussed, as a basis to search for a general and efficient procedure to solve the complex forward kinematics problem of platform-type manipulators. Several Screw-Theory based approaches for solving the inverse instantaneous problem of 6 DOF serial manipulators are studied and compared in terms of their computational efficiency, accuracy, sensitivity to data error and capability of dealing with singularities. A modified Vector Decomposition method is then proposed for solving the IIK problem and for singularity analysis of serial kinematic chains, the method is especially effective when applied to the wrist partitioned serial manipulators, which are essential components to any platform-type parallel manipulators. By using the data of three point positions, velocities, and accelerations of the end effector a general method is developed for solving the forward kinematics problem, including position, velocity and acceleration kinematics, of platform-type manipulators. The solution procedure can be applied to a wide variety of platform-type manipulators such as the 6 DOF Steward Platform manipulator and other models. It is found that while the solution for the forward position kinematics of a platform-type manipulator can be obtained by solving a non-linear system of equations, the closed-form solutions for forward rate and acceleration kinematics can be found by solving a system of linear equations. Based on the proposed kinematic formulations, an algorithm for detecting the boundaries of reachable workspace of platform-type manipulators is introduced, using a new concept of the Geometric Envelope. As the algorithm is based on the relatively simple inverse kinematic solution of platform-type manipulators, it is, in general, more efficient and easier to implement than any other existing methods for this purpose. Singular configurations of platform-type manipulators are discussed and a general analytical condition for configuration singularity is derived, based on the forward rate kinematics of platform-type manipulators. It is believed that this is one of the most general analytical expressions so far for singular configurations of a platform-type parallel manipulator.
Visual servoing of robot manipulators -- Part 1: Projective kinematics
Ruf, A.; Horaud, R.
1999-11-01
Visual servoing of robot manipulators is a key technique where the appearance of an object in the image plane is used to control the velocity of the end-effector such that the desired position is reached in the scene. The vast majority of visual servoing methods proposed so far uses calibrated robots in conjunction with calibrated cameras. It has been shown that the behavior of visual control loops does not degrade too much in the presence of calibration errors. Nevertheless, camera and robot calibration are complex and time-consuming processes requiring special-purpose mechanical devices, such as theodolites and calibration jigs. In this paper, the authors, suggest formulating a visual servoing control loop in nonmetric space, which in this case amounts to the projective space in which a triangulation of the scene using an uncalibrated stereo rig is expressed. The major consequence of controlling the robot in nonmetric space rather than in Euclidean space is that both the robot's direct kinematic map and the robot's Jacobian matrix must be defined in this space as well. Finally, they provide a practical method to estimate the projective kinematic model and they describe some preliminary simulated experiments that use this nonmetric model to perform stereo-based servoing. Nevertheless, in-depth analysis of projective control will be the topic of a forthcoming paper.
Moshin, Pavel Yu
2015-01-01
We continue our research arXiv:1405.0790[hep-th], arXiv:1405.7549[hep-th], arXiv:1406.0179[hep-th], arXiv:1406.5086[hep-th] and extend the class of finite BRST-antiBRST transformations with odd-valued parameters $\\lambda_{a}$, $a=1,2$, introduced in these works. In doing so, we calculate the Jacobians induced by linearized finite BRST-antiBRST transformations with functionally-dependent parameters, as well as those induced by finite BRST-antiBRST transformations with arbitrary functional parameters. The calculations cover the cases of gauge theories with a closed algebra, dynamical systems with first-class constraints, and general gauge theories. The resulting Jacobians in the case of linearized transformations are different from those in the case of polynomial dependence on the parameters. Finite BRST-antiBRST transformations with arbitrary parameters induce an extra contribution to the quantum action, which cannot be absorbed into a change of the gauge. These transformations include an extended case of func...
Kinematics: Speed, Velocity & Acceleration
NSDL National Science Digital Library
2010-01-01
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.
Weisenseel, P; Reich, K
2015-06-01
Inverse psoriasis is clinically defined by chronic inflammatory lesions in intertrigineous areas. Colonisation or infection with Candida ssp. or bacteria is common. The disease-related quality of life is significantly reduced especially regarding sexual behavior. After the exclusion of relevant differential diagnoses, therapy should be adapted to the clinical outcome and potential comorbidities. Substances which are efficacious in psoriasis vulgaris are generally efficacious in inverse psoriasis, but have to be used off-label. Controlled clinical studies are only available for topical ascomycin. PMID:25896586
ERIC Educational Resources Information Center
Coleman, J. J.
1982-01-01
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)
Slickenside kinematic indicators
Miguel Doblas; Consejo Superior de Investigaciones; JoseGutierrez Abascal
1998-01-01
A new classification of slickenside kinematic indicators is presented based on 61 criteria. These slickensides have been subdivided into eleven major groups: `V' or crescentic markings, steps, fractures, trains of inclined planar structures, trailed material, asymmetric elevations, deformed elements, mineralogical\\/crystallographic orientations, asymmetric plan-view features, asymmetric cavities, and asymmetric folds. This classification constitutes a useful tool for geologists interested in the
Jacobian and stiffness analysis of a novel class of six-DOF parallel minimanipulators
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
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.
Jacobian and stiffness analysis of a novel class of six-DOF parallel minimanipulators
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
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.
A systematic and effective supervised learning mechanism based on Jacobian rank deficiency.
Zhou, G; Si, J
1998-05-15
Most neural network applications rely on the fundamental approximation property of feedforward networks. Supervised learning is a means of implementing this approximate mapping. In a realistic problem setting, a mechanism is needed to devise this learning process based on available data, which encompasses choosing an appropriate set of parameters in order to avoid overfitting, using an efficient learning algorithm measured by computation and memory complexities, ensuring the accuracy of the training procedures as measured by the training error, and testing and cross-validation for generalization. We develop a comprehensive supervised learning algorithm to address these issues. The algorithm combines training and pruning into one procedure by utilizing a common observation of Jacobian rank deficiency in feedforward networks. The algorithm not only reduces the training time and overall complexity but also achieves training accuracy and generalization capabilities comparable to more standard approaches. Extensive simulation results are provided to demonstrate the effectiveness of the algorithm. PMID:9573418
Microwave spectrum of the HD2O+ ion: inversion-rotation transitions and inversion splitting.
Furuya, Takashi; Saito, Shuji
2008-01-21
Inversion-rotation spectral lines of the dideuterated hydronium ion, HD2O+, have been observed by a source-modulation millimeter- to submillimeter-wave spectrometer. The ion was generated by a hollow-cathode discharge in a gas mixture of D2O and H2O in a free-space cell. Ten inversion-rotation lines were measured precisely for the lowest pair of inversion doublets in the frequency region from 380 to 730 GHz. The observed lines include the most astronomically important transitions, 0(00) (-)-1(10)+ for the para species at 380 538.031(32) MHz and 1(01) (-)-1(11)+ for the ortho species at 728 420.189(34) MHz, which could be used as a radio astronomical probe investigating interstellar chemistry of deuterium fractionation. An analysis of the measured lines has yielded the rotational constants in the ground doublet states and the inversion splitting. The inversion splitting in the ground state was determined to be 808 866(34) MHz, that is, 26.980 87(113) cm(-1), where the numbers in parentheses give uncertainties estimated from the Jacobian matrix of the assumed centrifugal distortion constants. The determined inversion splitting is off by -0.51 cm(-1) from the predicted value of 27.49 cm(-1) by Rajamaki et al. using high-order coupled cluster ab initio calculation [J. Chem. Phys. 118, 10929 (2003)], and by -0.0510 cm(-1) from the observed value of 27.0318(72) cm(-1) by Dong et al. using high-resolution jet-cooled infrared spectroscopy [J. Chem. Phys. 122, 224301 (2005)] beyond the quoted uncertainty. PMID:18205502
Mesh Puppetry: Cascading Optimization of Mesh Deformation with Inverse Kinematics
Desbrun, Mathieu
-mail:{kunzhou,bainguo}@microsoft.com e-mail: {yiying,mathieu}@caltech.edu Figure 1: Armadillo Olympics: The Armadillo model (top left the Armadillo look like it is bouncing off a springboard (high diving, top right); or the pose of a sprint
Mesh Puppetry: Cascading Optimization of Mesh Deformation with Inverse Kinematics
Zhou, Kun
,mathieu}@caltech.edu Figure 1: Armadillo Olympics: The Armadillo model (top left) can be deformed to take various sport poses of its hands and feet is enough to make the Armadillo look like it is bouncing off a springboard (high
INVERSE KINEMATICS AND SINGULARITIES OF MANIPULATORS WITH OFFSET WRIST
Williams II, Robert L.
-2979 ABSTRACT The double universal joint robot wrist can eliminate singularities which limit the performance of existing industrial robot wrists. Unfortunately, this singularity-free wrist has an offset which prevents the overall manipulator singularity problem. KEY WORDS Offset robot wrist, Double universal joint robot wrist
NASA Astrophysics Data System (ADS)
Sergienko, Olga
2013-04-01
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.
Speaker independent acoustic-to-articulatory inversion
NASA Astrophysics Data System (ADS)
Ji, An
Acoustic-to-articulatory inversion, the determination of articulatory parameters from acoustic signals, is a difficult but important problem for many speech processing applications, such as automatic speech recognition (ASR) and computer aided pronunciation training (CAPT). In recent years, several approaches have been successfully implemented for speaker dependent models with parallel acoustic and kinematic training data. However, in many practical applications inversion is needed for new speakers for whom no articulatory data is available. In order to address this problem, this dissertation introduces a novel speaker adaptation approach called Parallel Reference Speaker Weighting (PRSW), based on parallel acoustic and articulatory Hidden Markov Models (HMM). This approach uses a robust normalized articulatory space and palate referenced articulatory features combined with speaker-weighted adaptation to form an inversion mapping for new speakers that can accurately estimate articulatory trajectories. The proposed PRSW method is evaluated on the newly collected Marquette electromagnetic articulography -- Mandarin Accented English (EMA-MAE) corpus using 20 native English speakers. Cross-speaker inversion results show that given a good selection of reference speakers with consistent acoustic and articulatory patterns, the PRSW approach gives good speaker independent inversion performance even without kinematic training data.
Parallel Kinematic Machines (PKM)
Henry, R.S.
2000-03-17
The purpose of this 3-year cooperative research project was to develop a parallel kinematic machining (PKM) capability for complex parts that normally require expensive multiple setups on conventional orthogonal machine tools. This non-conventional, non-orthogonal machining approach is based on a 6-axis positioning system commonly referred to as a hexapod. Sandia National Laboratories/New Mexico (SNL/NM) was the lead site responsible for a multitude of projects that defined the machining parameters and detailed the metrology of the hexapod. The role of the Kansas City Plant (KCP) in this project was limited to evaluating the application of this unique technology to production applications.
Slickenside kinematic indicators
NASA Astrophysics Data System (ADS)
Doblas, Miguel
1998-09-01
A new classification of slickenside kinematic indicators is presented based on 61 criteria. These slickensides have been subdivided into eleven major groups: `V' or crescentic markings, steps, fractures, trains of inclined planar structures, trailed material, asymmetric elevations, deformed elements, mineralogical/crystallographic orientations, asymmetric plan-view features, asymmetric cavities, and asymmetric folds. This classification constitutes a useful tool for geologists interested in the determination of the shear sense in fault surfaces bearing slickensides. Examples of application of this classification to natural fault surfaces at different scales are presented.
Kinematic Self-Similar Solutions
NASA Astrophysics Data System (ADS)
Sharif, M.; Aziz, S.
2005-04-01
We review some kinematic self-similar solutions of spherically symmetric spacetime. This analysis has been used to investigate the kinematic self-similar solutions of cylindrically symmetric spacetime. These have been discussed for the tilted case only. We have attempted solutions for the first, second, zeroth and infinite kind. The governing equations for perfect fluid cosmological models are introduced and a set of integrability conditions for the existence of a kinematic self-similar solutions are derived.
NASA Astrophysics Data System (ADS)
Godoy, William F.; Liu, Xu
2012-06-01
The present study introduces a parallel Jacobian-free Newton Krylov (JFNK) general minimal residual (GMRES) solution for the discretized radiative transfer equation (RTE) in 3D, absorbing, emitting and scattering media. For the angular and spatial discretization of the RTE, the discrete ordinates method (DOM) and the finite volume method (FVM) including flux limiters are employed, respectively. Instead of forming and storing a large Jacobian matrix, JFNK methods allow for large memory savings as the required Jacobian-vector products are rather approximated by semiexact and numerical formulations, for which convergence and computational times are presented. Parallelization of the GMRES solution is introduced in a combined memory-shared/memory-distributed formulation that takes advantage of the fact that only large vector arrays remain in the JFNK process. Results are presented for 3D test cases including a simple homogeneous, isotropic medium and a more complex non-homogeneous, non-isothermal, absorbing-emitting and anisotropic scattering medium with collimated intensities. Additionally, convergence and stability of Gram-Schmidt and Householder orthogonalizations for the Arnoldi process in the parallel GMRES algorithms are discussed and analyzed. Overall, the introduction of JFNK methods results in a parallel, yet scalable to the tested 2048 processors, and memory affordable solution to 3D radiative transfer problems without compromising the accuracy and convergence of a Newton-like solution.
Tetrahedral element shape optimization via the Jacobian determinant and condition number.
Freitag, L. A.; Knupp, P. M.
1999-07-30
We present a new shape measure for tetrahedral elements that is optimal in the sense that it gives the distance of a tetrahedron from the set of inverted elements. This measure is constructed from the condition number of the linear transformation between a unit equilateral tetrahedron and any tetrahedron with positive volume. We use this shape measure to formulate two optimization objective functions that are differentiated by their goal: the first seeks to improve the average quality of the tetrahedral mesh; the second aims to improve the worst-quality element in the mesh. Because the element condition number is not defined for tetrahedral with negative volume, these objective functions can be used only when the initial mesh is valid. Therefore, we formulate a third objective function using the determinant of the element Jacobian that is suitable for mesh untangling. We review the optimization techniques used with each objective function and present experimental results that demonstrate the effectiveness of the mesh improvement and untangling methods. We show that a combined optimization approach that uses both condition number objective functions obtains the best-quality meshes.
Homoclinic tangencies and non-normal Jacobians - Effects of noise in nonhyperbolic chaotic systems
NASA Astrophysics Data System (ADS)
Jaeger, Lars; Kantz, Holger
1997-02-01
A general study of the effects of noise interacting with the deterministic dynamics of nonhyperbolic chaotic 2-D maps and 3-flows is presented. Noise in these systems can have dramatic effects on the invariant measure of the system. In regions of homoclinic tangencies perturbations are transported away from the neighborhood of the attractor, leading to deformations which can be one to two orders of magnitude larger than the noise level. A qualitative understanding is attained by a study of the universal properties of the unstable and stable foliation of the phase space in the vicinity of homoclinic tangencies. Through the investigation of nontrivial structures of the tangent space at homoclinic tangencies related to the non-normal Jacobians we obtain a quantitative description of these noise-induced deformations of the attractor. Local expansion rates which are much larger than the maximal Lyapunov exponent can be used as a measure of the system's structural instability under perturbations. We exemplify our general results on the Hénon, Ikeda and Duffing system. A new and effective algorithm to calculate the homoclinic tangencies in the entire phase space based on the results of this paper is presented.
Kinematics of Strong Discontinuities
NASA Technical Reports Server (NTRS)
Peterson, K.; Nguyen, G.; Sulsky, D.
2006-01-01
Synthetic Aperture Radar (SAR) provides a detailed view of the Arctic ice cover. When processed with the RADARSAT Geophysical Processor System (RGPS), it provides estimates of sea ice motion and deformation over large regions of the Arctic for extended periods of time. The deformation is dominated by the appearance of linear kinematic features that have been associated with the presence of leads. The RGPS deformation products are based on the assumption that the displacement and velocity are smooth functions of the spatial coordinates. However, if the dominant deformation of multiyear ice results from the opening, closing and shearing of leads, then the displacement and velocity can be discontinuous. This presentation discusses the kinematics associated with strong discontinuities that describe possible jumps in displacement or velocity. Ice motion from SAR data are analyzed using this framework. It is assumed that RGPS cells deform due to the presence of a lead. The lead orientation is calculated to optimally account for the observed deformation. It is shown that almost all observed deformation can be represented by lead opening and shearing. The procedure used to reprocess motion data to account for leads will be described and applied to regions of the Beaufort Sea. The procedure not only provides a new view of ice deformation, it can be used to obtain information about the presence of leads for initialization and/or validation of numerical simulations.
Kinematics of Globular Cluster Systems
Aaron J. Romanowsky
2006-09-08
I review the field of globular cluster system (GCS) kinematics, including a brief primer on observational methods. The kinematical structures of spiral galaxy GCSs so far appear to be broadly similar. The inferred rotation and mass profiles of elliptical galaxy halos exhibit a diversity of behaviors, requiring more systematic observational and theoretical studies.
Joint inversion of acoustic and resistivity data for the estimation of gas hydrate concentration
Lee, Myung W.
2002-01-01
Downhole log measurements, such as acoustic or electrical resistivity logs, are frequently used to estimate in situ gas hydrate concentrations in the pore space of sedimentary rocks. Usually the gas hydrate concentration is estimated separately based on each log measurement. However, measurements are related to each other through the gas hydrate concentration, so the gas hydrate concentrations can be estimated by jointly inverting available logs. Because the magnitude of slowness of acoustic and resistivity values differs by more than an order of magnitude, a least-squares method, weighted by the inverse of the observed values, is attempted. Estimating the resistivity of connate water and gas hydrate concentration simultaneously is problematic, because the resistivity of connate water is independent of acoustics. In order to overcome this problem, a coupling constant is introduced in the Jacobian matrix. In the use of different logs to estimate gas hydrate concentration, a joint inversion of different measurements is preferred to the averaging of each inversion result.
Fast Iterative Implementation of Nonlinear Geostatistical Inverse Modeling
NASA Astrophysics Data System (ADS)
Liu, X.; Zhou, Q.; Kitanidis, P. K.
2012-12-01
Previous research reduced the dimensionality of the under-determined geostatistical inverse problems from the number of unknowns (m) to the number of measurements (n), and a fair amount of reduction in computational cost have been achieved when n<
Detailed solution to a complex kinematics chain manipulator
March-Leuba, S.; Jansen, J.F.; Kress, R.L.; Babcock, S.M.
1992-12-31
This paper presents a relatively simple method based on planar geometry to analyze the inverse kinematics for closed kinematics chain (CKC) mechanisms. Although the general problem and method of approach are well defined, the study of the inverse kinematics of a closed-chain mechanism is a very complicated one. The current methodology allows closed-form solutions to be found, if a solution exists, for the displacements and velocities of all manipulator joints. Critical design parameters can be identified and optimized by using symbolic models. This paper will focus on planar closed-chain structures extended with a rotational base. However, with open and CKC mechanisms combined in different planes, the extension to the case is straightforward. Further, real-time algorithms are developed that can be handled by existing microprocessor technology. To clarify the methodology, the Soldier Robot Interface Project (SRIP) manipulator is analyzed, and a graphic simulation is presented as a verification of the results. This manipulator has 17 links, 24 one-degree-of-freedom (DOF) joints, and 7 CKC loops working in a plane and a rotational base, which determine its 3 DOFs. The SRIP manipulator allows a decoupled linear motion along the vertical or horizontal directions using only one of its linear actuators. The symbolic solution for the inverse kinematics allows optimization to be performed to further decouple the Cartesian motions by changing link lengths of the manipulator. The conclusion achieved by the optimization is that only two link lengths need to be changed to tune the manipulator for a perfect decoupling at each area of the workspace.
Detailed solution to a complex kinematics chain manipulator
March-Leuba, S; Jansen, J F; Kress, R L; Babcock, S M
1992-01-01
This paper presents a relatively simple method based on planar geometry to analyze the inverse kinematics for closed kinematics chain (CKC) mechanisms. Although the general problem and method of approach are well defined, the study of the inverse kinematics of a closed-chain mechanism is a very complicated one. The current methodology allows closed-form solutions to be found, if a solution exists, for the displacements and velocities of all manipulator joints. Critical design parameters can be identified and optimized by using symbolic models. This paper will focus on planar closed-chain structures extended with a rotational base. However, with open and CKC mechanisms combined in different planes, the extension to the case is straightforward. Further, real-time algorithms are developed that can be handled by existing microprocessor technology. To clarify the methodology, the Soldier Robot Interface Project (SRIP) manipulator is analyzed, and a graphic simulation is presented as a verification of the results. This manipulator has 17 links, 24 one-degree-of-freedom (DOF) joints, and 7 CKC loops working in a plane and a rotational base, which determine its 3 DOFs. The SRIP manipulator allows a decoupled linear motion along the vertical or horizontal directions using only one of its linear actuators. The symbolic solution for the inverse kinematics allows optimization to be performed to further decouple the Cartesian motions by changing link lengths of the manipulator. The conclusion achieved by the optimization is that only two link lengths need to be changed to tune the manipulator for a perfect decoupling at each area of the workspace.
Abel inversions: Error propagation and inversion reliability
A. T. Ramsey; M. Diesso
1999-01-01
Inversion of chordally integrated data to infer the profile of a plasma parameter (plasma density, radiated power, or, in our case, the visible continuum from bremsstrahlung) propagates errors from outer shells inward as the inversion progresses. If the inversion is done by a matrix technique, error propagation can likewise be determined by a matrix technique. Where other considerations make the
NASA Astrophysics Data System (ADS)
Liu, Xiao-Bo; Liu, Fu-Ping; Meng, Xian-Jun; Xiao, Jia-Qi
2012-03-01
The optimization inversion method based on derivatives is an important inversion technique in seismic data processing, where the key problem is how to compute the Jacobian matrix. The computational precision of the Jacobian matrix directly influences the success of the optimization inversion method. Currently, most of the AVO (amplitude versus offset) inversions are based on approximate expressions for the Zoeppritz equations to obtain the derivatives of the seismic wave reflection coefficients (SWRCs) with respect to the stratum parameters. As a result, the computational precision and range of applications of these AVO inversions are restricted undesirably. In order to improve the computational precision and to extend the range of applications of AVO inversions, the partial derivative equations of the Zoeppritz equations are established, with respect to the ratios of wave velocities and medium densities. By solving the partial derivative equations of the Zoeppritz equations accurately, we obtained the partial derivative of SWRCs with respect to the ratios of seismic wave velocities and medium densities. With the help of the chain rule for derivatives, the gradient of the SWRCs can be accurately computed. To better understand the behavior of the gradient of the SWRCs, we plotted the partial derivative curves of the SWRCs, analyzed the characteristics of these curves, and gained some new insight into the derivatives. Because only a linear system of equations is solved in our method without adding any new restrictions, the new computational method has both high precision and a quick running speed; it is not only suitable for small incident angles and weak reflection seismic waves but also for large incident angles and strong reflection seismic waves. With the theoretical foundations established in the article, we can further study inversion problems for layered stratum structures and we can further improve the computational speed and precision of the inversions.
Kinematics, controls, and path planning results for a redundant manipulator
NASA Technical Reports Server (NTRS)
Gretz, Bruce; Tilley, Scott W.
1989-01-01
The inverse kinematics solution, a modal position control algorithm, and path planning results for a 7 degree of freedom manipulator are presented. The redundant arm consists of two links with shoulder and elbow joints and a spherical wrist. The inverse kinematics problem for tip position is solved and the redundant joint is identified. It is also shown that a locus of tip positions exists in which there are kinematic limitations on self-motion. A computationally simple modal position control algorithm has been developed which guarantees a nearly constant closed-loop dynamic response throughout the workspace. If all closed-loop poles are assigned to the same location, the algorithm can be implemented with very little computation. To further reduce the required computation, the modal gains are updated only at discrete time intervals. Criteria are developed for the frequency of these updates. For commanding manipulator movements, a 5th-order spline which minimizes jerk provides a smooth tip-space path. Schemes for deriving a corresponding joint-space trajectory are discussed. Modifying the trajectory to avoid joint torque saturation when a tip payload is added is also considered. Simulation results are presented.
HyeongKae Park; Robert R. Nourgaliev; Richard C. Martineau; Dana A. Knoll
2008-09-01
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.
Kinematic precision of gear trains
NASA Technical Reports Server (NTRS)
Litvin, F. L.; Goldrich, R. N.; Coy, J. J.; Zaretsky, E. V.
1982-01-01
Kinematic precision is affected by errors which are the result of either intentional adjustments or accidental defects in manufacturing and assembly of gear trains. A method for the determination of kinematic precision of gear trains is described. The method is based on the exact kinematic relations for the contact point motions of the gear tooth surfaces under the influence of errors. An approximate method is also explained. Example applications of the general approximate methods are demonstrated for gear trains consisting of involute (spur and helical) gears, circular arc (Wildhaber-Novikov) gears, and spiral bevel gears. Gear noise measurements from a helicopter transmission are presented and discussed with relation to the kinematic precision theory.
Rosen, Jacob
to the inverse kinematics. The redundancy of a wearable robotic system (exoskeleton) that interacts robots such as the wearable exoskeleton robot [1] directly interact with humans to enhance or support system (exoskeleton) such that it will be able to render motions as natural as that of the human arm
Ground reaction forces, kinematics, and muscle activations during the windmill softball pitch
Gretchen D. Oliver; Hillary Plummer
2011-01-01
The aims of the present study were to examine quantitatively ground reaction forces, kinematics, and muscle activations during the windmill softball pitch, and to determine relationships between knee valgus and muscle activations, ball velocity and muscle activation as well as ball velocity and ground reaction forces. It was hypothesized that there would be an inverse relationship between degree of knee
A. Linden; J. Kindermann
1989-01-01
The method of inversion for arbitrary continuous multilayer nets is developed. The inversion is done by computing iteratively an input vector which minimizes the least-mean-square errors to approximate a given output target. This inversion is not unique for given targets and depends on the starting point in input space. The inversion method turns out to be a valuable tool for
Kinematics of a New High Precision Three Degree-of-Freedom Parallel Manipulator
NASA Technical Reports Server (NTRS)
Tahmasebi, Farhad
2005-01-01
Closed-form direct and inverse kinematics of a new three degree-of-freedom (DOF) parallel manipulator with inextensible limbs and base-mounted actuators are presented. The manipulator has higher resolution and precision than the existing three DOF mechanisms with extensible limbs. Since all of the manipulator actuators are base-mounted; higher payload capacity, smaller actuator sizes, and lower power dissipation can be obtained. The manipulator is suitable for alignment applications where only tip, tilt, and piston motions are significant. The direct kinematics of the manipulator is reduced to solving an eighth-degree polynomial in the square of tangent of half-angle between one of the limbs and the base plane. Hence, there are at most sixteen assembly configurations for the manipulator. In addition, it is shown that the sixteen solutions are eight pairs of reflected configurations with respect to the base plane. Numerical examples for the direct and inverse kinematics of the manipulator are also presented.
Solving coupled groundwater flow systems using a Jacobian Free Newton Krylov method
NASA Astrophysics Data System (ADS)
Mehl, S.
2012-12-01
Jacobian Free Newton Kyrlov (JFNK) methods can have several advantages for simulating coupled groundwater flow processes versus conventional methods. Conventional methods are defined here as those based on an iterative coupling (rather than a direct coupling) and/or that use Picard iteration rather than Newton iteration. In an iterative coupling, the systems are solved separately, coupling information is updated and exchanged between the systems, and the systems are re-solved, etc., until convergence is achieved. Trusted simulators, such as Modflow, are based on these conventional methods of coupling and work well in many cases. An advantage of the JFNK method is that it only requires calculation of the residual vector of the system of equations and thus can make use of existing simulators regardless of how the equations are formulated. This opens the possibility of coupling different process models via augmentation of a residual vector by each separate process, which often requires substantially fewer changes to the existing source code than if the processes were directly coupled. However, appropriate perturbation sizes need to be determined for accurate approximations of the Frechet derivative, which is not always straightforward. Furthermore, preconditioning is necessary for reasonable convergence of the linear solution required at each Kyrlov iteration. Existing preconditioners can be used and applied separately to each process which maximizes use of existing code and robust preconditioners. In this work, iteratively coupled parent-child local grid refinement models of groundwater flow and groundwater flow models with nonlinear exchanges to streams are used to demonstrate the utility of the JFNK approach for Modflow models. Use of incomplete Cholesky preconditioners with various levels of fill are examined on a suite of nonlinear and linear models to analyze the effect of the preconditioner. Comparisons of convergence and computer simulation time are made using conventional iteratively coupled methods and those based on Picard iteration to those formulated with JFNK to gain insights on the types of nonlinearities and system features that make one approach advantageous. Results indicate that nonlinearities associated with stream/aquifer exchanges are more problematic than those resulting from unconfined flow.
Deformation field validation and inversion applied to adaptive radiation therapy
NASA Astrophysics Data System (ADS)
Vercauteren, Tom; De Gersem, Werner; Olteanu, Luiza A. M.; Madani, Indira; Duprez, Fréderic; Berwouts, Dieter; Speleers, Bruno; De Neve, Wilfried
2013-08-01
Development and implementation of chronological and anti-chronological adaptive dose accumulation strategies in adaptive intensity-modulated radiation therapy (IMRT) for head-and-neck cancer. An algorithm based on Newton iterations was implemented to efficiently compute inverse deformation fields (DFs). Four verification steps were performed to ensure a valid dose propagation: intra-cell folding detection finds zero or negative Jacobian determinants in the input DF; inter-cell folding detection is implemented on the resolution of the output DF; a region growing algorithm detects undefined values in the output DF; DF domains can be composed and displayed on the CT data. In 2011, one patient with nonmetastatic head and neck cancer selected from a three phase adaptive DPBN study was used to illustrate the algorithms implemented for adaptive chronological and anti-chronological dose accumulation. The patient received three 18F-FDG-PET/CTs prior to each treatment phase and one CT after finalizing treatment. Contour propagation and DF generation between two consecutive CTs was performed in Atlas-based autosegmentation (ABAS). Deformable image registration based dose accumulations were performed on CT1 and CT4. Dose propagation was done using combinations of DFs or their inversions. We have implemented a chronological and anti-chronological dose accumulation algorithm based on DF inversion. Algorithms were designed and implemented to detect cell folding.
Dana A. Knoll; H. Park; Kord Smith
2011-02-01
The use of the Jacobian-free Newton-Krylov (JFNK) method within the context of nonlinear diffusion acceleration (NDA) of source iteration is explored. The JFNK method is a synergistic combination of Newton's method as the nonlinear solver and Krylov methods as the linear solver. JFNK methods do not form or store the Jacobian matrix, and Newton's method is executed via probing the nonlinear discrete function to approximate the required matrix-vector products. Current application of NDA relies upon a fixed-point, or Picard, iteration to resolve the nonlinearity. We show that the JFNK method can be used to replace this Picard iteration with a Newton iteration. The Picard linearization is retained as a preconditioner. We show that the resulting JFNK-NDA capability provides benefit in some regimes. Furthermore, we study the effects of a two-grid approach, and the required intergrid transfers when the higher-order transport method is solved on a fine mesh compared to the low-order acceleration problem.
A global approach for using kinematic redundancy to minimize base reactions of manipulators
NASA Technical Reports Server (NTRS)
Chung, C. L.; Desa, S.
1989-01-01
An important consideration in the use of manipulators in microgravity environments is the minimization of the base reactions, i.e. the magnitude of the force and the moment exerted by the manipulator on its base as it performs its tasks. One approach which was proposed and implemented is to use the redundant degree of freedom in a kinematically redundant manipulator to plan manipulator trajectories to minimize base reactions. A global approach was developed for minimizing the magnitude of the base reactions for kinematically redundant manipulators which integrates the Partitioned Jacobian method of redundancy resolution, a 4-3-4 joint-trajectory representation and the minimization of a cost function which is the time-integral of the magnitude of the base reactions. The global approach was also compared with a local approach developed earlier for the case of point-to-point motion of a three degree-of-freedom planar manipulator with one redundant degree-of-freedom. The results show that the global approach is more effective in reducing and smoothing the base force while the local approach is superior in reducing the base moment.
Kinematics and dynamics of deployable structures with scissor-like-elements based on screw theory
NASA Astrophysics Data System (ADS)
Sun, Yuantao; Wang, Sanmin; Mills, James K.; Zhi, Changjian
2014-07-01
Because the deployable structures are complex multi-loop structures and methods of derivation which lead to simpler kinematic and dynamic equations of motion are the subject of research effort, the kinematics and dynamics of deployable structures with scissor-like-elements are presented based on screw theory and the principle of virtual work respectively. According to the geometric characteristic of the deployable structure examined, the basic structural unit is the common scissor-like-element(SLE). First, a spatial deployable structure, comprised of three SLEs, is defined, and the constraint topology graph is obtained. The equations of motion are then derived based on screw theory and the geometric nature of scissor elements. Second, to develop the dynamics of the whole deployable structure, the local coordinates of the SLEs and the Jacobian matrices of the center of mass of the deployable structure are derived. Then, the equivalent forces are assembled and added in the equations of motion based on the principle of virtual work. Finally, dynamic behavior and unfolded process of the deployable structure are simulated. Its figures of velocity, acceleration and input torque are obtained based on the simulate results. Screw theory not only provides an efficient solution formulation and theory guidance for complex multi-closed loop deployable structures, but also extends the method to solve dynamics of deployable structures. As an efficient mathematical tool, the simper equations of motion are derived based on screw theory.
KINEMATIC ANALYSIS OF MODULAR, TRUSS-BASED MANIPULATOR UNITS
Salerno, R. J.
1994-06-01
Decontamination and Dismantling (D&D) activities within the U.S. Department of Energy (DOE) require a long reach manipulator with a large load capacity. Variable Geometry Trusses (VGTs) are a unique class of mechanical structures which allow the advantages of truss structures for large scale applications to be applied to large robotic manipulators. Individual VGT units may be assembled to create a modular, long-reach, truss-type manipulator. Each module of such a manipulator system is either a static truss section or one of several possible VGT geometries. While many potential applications exist for this technology, the present work is largely motivated by the need for generic robotic systems for remote manipulation. A manipulator system based on VGT modules provides several advantages. The reconfigurable nature of the manipulator system allows it to be adapted on site to unforeseen conditions. The kinematic redundancy of the manipulator enables it to work effectively even in a highly obstructed workspace. The parallel structure of the truss modules enables the manipulator to be withdrawn in the event of a structural failure. Finally, the open framework of the modules provides a clear, protected passageway for control and power cabling, waste conveyance, or other services required at the end effector. As is implied in a truss structure, all primary members of a VGT are ideally loaded in pure tension or compression. This results in an extremely stiff and strong manipulator system with minimal overall weight. Careful design of the joints of a VGT is very important to the overall stiffness and accuracy of the structure, as several links (as many as six) are joined together at each joint. The greatest disadvantage to this approach to manipulator design has traditionally been that the kinematics of VGT structures are complex and poorly understood. This report specifically addresses the kinematics of several possible geometries for the individual VGT units. Equations and solution techniques are developed for solving the "forward" or "direct" and "inverse" kinematic problems for these geometries. The" forward" kinematic problem is that of finding the position and orientation of the distal end of the VGT relative to the proximal end, given the specific displacements of the (linear) actuators. This problem is rarely solvable in closed form. However, powerful iterative algorithms capable of solution in real time on typical modern robot control hardware are presented. The "inverse" kinematic problem is that of finding the required actuator displacements given the position and orientation of the distal end of the VGT relative to the proximal end. For specific VGT geometries, closed-form solutions are presented. For the more general problem, iterative algorithms capable of solution in real time are again derived and presented.
Reconstruction procedures for two inverse scattering problems without the phase information
Michael V. Klibanov; Vladimir G. Romanov
2015-05-08
This is a continuation of two recent publications of the authors about reconstruction procedures for 3-d phaseless inverse scattering problems. The main novelty of this paper is that the Born approximation for the case of the wave-like equation is not considered. It is shown here that the phaseless inverse scattering problem for the 3-d wave-like equation in the frequency domain leads to the well known Inverse Kinematic Problem. Uniqueness theorem follows. Still, since the Inverse Kinematic Problem is very hard to solve, a linearization is applied. More precisely, geodesic lines are replaced with straight lines. As a result, an approximate explicit reconstruction formula is obtained via the inverse Radon transform. The second reconstruction method is via solving a problem of the integral geometry using integral equations of the Abel type.
Kinematic sensitivity of robot manipulators
NASA Technical Reports Server (NTRS)
Vuskovic, Marko I.
1989-01-01
Kinematic sensitivity vectors and matrices for open-loop, n degrees-of-freedom manipulators are derived. First-order sensitivity vectors are defined as partial derivatives of the manipulator's position and orientation with respect to its geometrical parameters. The four-parameter kinematic model is considered, as well as the five-parameter model in case of nominally parallel joint axes. Sensitivity vectors are expressed in terms of coordinate axes of manipulator frames. Second-order sensitivity vectors, the partial derivatives of first-order sensitivity vectors, are also considered. It is shown that second-order sensitivity vectors can be expressed as vector products of the first-order sensitivity vectors.
Emergent gravity requires kinematic nonlocality.
Marolf, Donald
2015-01-23
This Letter refines arguments forbidding nonlinear dynamical gravity from appearing in the low energy effective description of field theories with local kinematics, even for those with instantaneous long-range interactions. Specifically, we note that gravitational theories with universal coupling to energy-an intrinsically nonlinear phenomenon-are characterized by Hamiltonians that are pure boundary terms on shell. In order for this to be the low energy effective description of a field theory with local kinematics, all bulk dynamics must be frozen and, thus, irrelevant to the construction. The result applies to theories defined either on a lattice or in the continuum, and requires neither Lorentz invariance nor translation invariance. PMID:25658991
Paris-Sud XI, Université de
Robust fusion of Jacobian maps for Deformation-Based Morphometry Nicolas Guizard with Magnetic Resonance Imaging (MRI), Deformation-Based Morphometry (DBM) [Ashburner, 1998] has received more for normalization. Registration errors due to anatomical singularities such as non-homologous gyri, the presence
Dorst, Leo
angle and an elbow angle . The upper arm has length `1, the lower arm length `2. The `hand' of the robot is the Jacobian in this state? Answer: (; 1p2 ;1) ;1 1p2 0 ! (5) (b) Let the robot wave a little, from the elbow
Kinematic solution of spherical Stephenson-III six-bar mechanism
NASA Astrophysics Data System (ADS)
Liu, Yanfang; Yang, Suixian
2013-09-01
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.
Locative Inversion in Cantonese.
ERIC Educational Resources Information Center
Mok, Sui-Sang
This study investigates the phenomenon of "Locative Inversion" in Cantonese. The term "Locative Inversion" indicates that the locative phrase (LP) syntactic process in Cantonese and the appears at the sentence-initial position and its logical subject occurs postverbally. It is demonstrated that this Locative Inversion is a widespread syntactic…
NASA Technical Reports Server (NTRS)
Nguyen, Charles C.; Pooran, Farhad J.
1989-01-01
This report presents results from the research grant entitled Active Control of Robot Manipulators, funded by the Goddard Space Flight Center, under Grant NAG5-780, for the period July 1, 1988 to January 1, 1989. An analysis is presented of a 6 degree-of-freedom robot end-effector built to study telerobotic assembly of NASA hardware in space. Since the end-effector is required to perform high precision motion in a limited workspace, closed-kinematic mechanisms are chosen for its design. A closed-form solution is obtained for the inverse kinematic problem and an iterative procedure employing Newton-Raphson method is proposed to solve the forward kinematic problem. A study of the end-effector workspace results in a general procedure for the workspace determination based on link constraints. Computer simulation results are presented.
Righting kinematics in beetles (Insecta: Coleoptera).
Frantsevich, Leonid
2004-07-01
Twenty modes of stereotyped righting motions were observed in 116 representative species of coleoptera. Methods included cine and stereocine recording with further frame by frame analysis, stereogrammetry, inverse kinematic reconstruction of joint angles, stroboscopic photography, recording of electromyograms, 3D measurements of the articulations, etc. The basic mode consists of a search phase, ending up with grasping the substrate, and a righting, overturning phase. Leg coordination within the search cycle differs from the walking cycle with respect to phasing of certain muscle groups. Search movements of all legs appear chaotic, but the tendency to move in antiphase is still present in adjacent ipsilateral and contralateral leg pairs. The system of leg coordination might be split: legs of one side might search, while contralateral legs walk, or fore and middle legs walk while hind legs search. Elaborated types of righting include somersaults with the aid of contralateral or diagonal legs, pitch on elytra, jumps with previous energy storage with the aid of unbending between thoracic segments (well-known for Elateridae), or quick folding of elytra (originally described in Histeridae). Righting in beetles is compared with righting modes known in locusts and cockroaches. Search in a righting beetle is directed dorsad, while a walking insect searches for the ground downwards. Main righting modes were schematized for possible application to robotics. PMID:18089036
Kinematics and trajectory generation for MIRADAS arms
NASA Astrophysics Data System (ADS)
Sabater, J.; Gómez, J. M.; Torra, J.; López, M.; Raines, S. N.; Eikenberry, S. S.
2015-05-01
The Mid-resolution InfRAreD Astronomical Spectrograph (MIRADAS) is a NIR multi-object spectrograph for the Gran Telescopio Canarias (GTC). The instrument has a multiplexing system (MXS) that enables the simultaneous observation of twenty objects located within its field of view. These user selected targets are acquired by twenty deployable robotic probe arms with pickoff mirror optics operating at cryogenic temperatures. The MIRADAS probe arm is a close-loop mechanism designed with optics simplicity in mind, presenting good stability when it is operated upside down. Calculating optimum collision-free trajectories requires a good knowledge of the MIRADAS arm behavior based on its geometry and its mechanical constraints. This study introduces a geometric model for the two degree-of-freedom (DoF) mechanism, including solutions for the forward and inverse kinematics problem. The concepts of zone-of-avoidance (ZoA), workspace and envelope of MIRADAS arm are presented and studied. Finally, the paper proposes two different patrolling approaches that can be exploited when planning trajectories.
Kinematic Parameters of Signed Verbs
ERIC Educational Resources Information Center
Malaia, Evie; Wilbur, Ronnie B.; Milkovic, Marina
2013-01-01
Purpose: Sign language users recruit physical properties of visual motion to convey linguistic information. Research on American Sign Language (ASL) indicates that signers systematically use kinematic features (e.g., velocity, deceleration) of dominant hand motion for distinguishing specific semantic properties of verb classes in production…
The kinematics of lopsided galaxies
Edo Noordermeer; Linda S. Sparke; Stephen E. Levine
2001-12-13
Lopsidedness is a common feature in galaxies, both in the distribution of light and in the kinematics. We investigate the kinematics of a model for lopsided galaxies that consists of a disc lying off-centre in a dark halo, and circling around the halo centre. We search for families of stable, closed, non-crossing orbits, and assume that gas in our galaxies moves on these orbits. Several of our models show strong lopsided gas kinematics, especially the ones in which the disc spins around its axis in a retrograde sense compared to its motion around the halo centre. We are able to reproduce the HI velocity map of the kinematically lopsided galaxy NGC 4395. The lopsidedness in our models is most pronounced in the models where the halo provides a relatively large fraction of the total mass at small radii. This may explain why the gas shows lopsidedness more frequently in late-type galaxies, which are dominated by dark matter. Surfaces of section show large regions of irregular orbits in the models where the halo density is low. This may indicate that these models are unstable.
Barberis, Emanuela; /Northeastern U.
2006-05-01
A summary of the results on the measurement of the Top Quark mass and the study of the kinematics of the t{bar t} system at the Tevatron collider is presented here. Results from both the CDF and D0 collaborations are reported.
Kinematics Equations for Differential Drive
Hellström, Thomas
concept for the derivation of the kinematics equations is the Angular velocity of the robot that is NOT an angular polar coordinate for the position, instead it points in the forward direction of the robot. Figure / T where T is the time it would take to complete one full turn around ICC. The angular velocity is defined
Robotics and Autonomous Systems 58 (2010) 648656 Contents lists available at ScienceDirect
Kim, Jongwon
2010-01-01
on kinematics for a quadruped gecko model with redundancy Donghoon Sona , Dongsu Jeona , Woo Chul Nama , Doyoung by a gecko lizard. Our gait planning was based on inverse kinematics using the Jacobian of the whole body, where the redundancy was solved by defining an object function for the gecko posture to avoid collisions
NASA Astrophysics Data System (ADS)
Rodríguez-Sánchez, J. L.; Benlliure, J.; Taïeb, J.; Ayyad, Y.; Bélier, G.; Boutoux, G.; Casarejos, E.; Chatillon, A.; Gorbinet, T.; Laurent, B.; Martin, J.-F.; Paradela, C.; Pellereau, E.; Álvarez-Pol, H.; Audouin, L.; Cortina-Gil, D.; Heinz, A.; Kelié-Heil, A.; Pietras, B.; Ramos, D.; Rodríguez-Tajes, C.; Rossi, D.; Simon, H.; Tassan-Got, L.; Vargas, J.; Voss, B.
Proton-induced fission of 208Pb has been investigated at 370, 500 and 650 A MeV in complete kinematic measurements. The experiment was performed at GSI Darmstadt where the combined use of the inverse kinematics technique with an efficient detection setup allowed to measure for the first time the atomic and mass number of both fission fragments. The performed measurement together with different model calculations allow us to investigate dissipative and transient effects in the fission process and the dependence on temperature and deformation of the dissipation strength ?. The use of spallation reactions with lead projectiles favours this study due to its high excitation energy and low angular momentum.
Kinematics of Galaxies Spectral Features of Galaxies
Crenshaw, Michael
Kinematics Â· Faber-Jackson and the Fundamental Plane Â· Disk Kinematics (Stellar and H I) Â· 2D Velocity Fields-Line Centroid: c lab r lab v c - = 3c. Radial Velocity Centroid: (nonrelativistic) (Ã?) (km s-1) Fc Fc F F F (Binney & Merrifield p.695, 698) #12;12 Results for Ellipticals: Kinematic Correlations Â· Faber-Jackson
Abel inversions: Error propagation and inversion reliability
Ramsey, A.T.; Diesso, M. [Plasma Physics Laboratory, Princeton University, Princeton, New Jersey 08543 (United States)] [Plasma Physics Laboratory, Princeton University, Princeton, New Jersey 08543 (United States)
1999-01-01
Inversion of chordally integrated data to infer the profile of a plasma parameter (plasma density, radiated power, or, in our case, the visible continuum from bremsstrahlung) propagates errors from outer shells inward as the inversion progresses. If the inversion is done by a matrix technique, error propagation can likewise be determined by a matrix technique. Where other considerations make the matrix method undesirable, there is no clearly defined analytical method to test the reliability of the inversion. We have solved this problem by taking real data from the Tokamak Fusion Test Reactor (TFTR) visible bremsstrahlung (VB) diagnostic, applying normally distributed random noise of a known mean value, and inverting the signal. When we have done this hundreds of times at all points in the profile, we can clearly track the error propagation. At the plasma center, for example, the error is several times the average error in the relative (chord to chord) calibration of the system. This error multiplier is a powerful generalization; it depends little on the details of the inversion, and almost entirely on the profile shape. For the TFTR VB profile it ranges from 2 to 4 for most types of plasma. We have also looked at the damping of the inversion error from an error in a single chord; this damping can be rather fast in some cases. {copyright} {ital 1999 American Institute of Physics.}
NASA Astrophysics Data System (ADS)
Jen, Fu-Hua
This work studies three related aspects of robotics: the set of possible kinematic representations of robot motion, the range of all possible robot positions, i.e., the workspace, and the designing of stable grasps with a multifingered end-effector. A survey of alternatives to the homogeneous transformation to represent robot coordinate translations and rotations is given. The advantages and disadvantages of each are discussed, and their computational complexities are compared, giving the number of arithmetic operations required by the different methods. In viewing rigid body motions, two aspects are considered: point transformations, which result in matrix-based transformations, and line transformations, which result in screw-based transformations. Algebraic expressions for the robot workspace are helpful in the design of robots. Here, a complete methodology is developed to obtain algebraic expressions to aid robot workspace construction, based on the analysis of Jacobian matrices. Reduction of the complexity of the workspace analysis is achieved by choice of the coordinate system used in the representation. It is shown that, in the worst case 2 x 2 submatrices of the Jacobian need to be checked, and with some specific kinematic structures, it is sufficient to examine only a set of scalar expressions. Examples of using algebraic expressions to generate workspace without mechanical limitations are given. The third part of this work represents the first application of Liapunov stability theory of differential equations to the problem of generating stable grasps of an object with a multifingered hand. The analysis of grasp stability where finger forces are maintained constant is considered, as well as certain modified force control laws that introduce damping. In the robotics community there is considerable research emphasis related to the use of force control methods rather than the usual position control, and this motivates the study. Stability theory for nonlinear differential equations is applied to establish the conditions on finger locations and grasp force directions that are associated with Liapunov stability, with asymptotic stability, and with instability of grasps. Relationships are given between these mathematical concepts and various desirable properties of grasp that have previously been used in defining various concepts of stable grasp. A geometrical representation of the stability condition is given which assists the synthesis of the grasp, and examples in two and three dimensions are given.
Robust magnetotelluric inversion
NASA Astrophysics Data System (ADS)
Matsuno, Tetsuo; Chave, Alan D.; Jones, Alan G.; Muller, Mark R.; Evans, Rob L.
2014-03-01
A robust magnetotelluric (MT) inversion algorithm has been developed on the basis of quantile-quantile (q-q) plotting with confidence band and statistical modelling of inversion residuals for the MT response function (apparent resistivity and phase). Once outliers in the inversion residuals are detected in the q-q plot with the confidence band and the statistical modelling with the Akaike information criterion, they are excluded from the inversion data set and a subsequent inversion is implemented with the culled data set. The exclusion of outliers and the subsequent inversion is repeated until the q-q plot is substantially linear within the confidence band, outliers predicted by the statistical modelling are unchanged from the prior inversion, and the misfit statistic is unchanged at a target level. The robust inversion algorithm was applied to synthetic data generated from a simple 2-D model and observational data from a 2-D transect in southern Africa. Outliers in the synthetic data, which come from extreme values added to the synthetic responses, produced spurious features in inversion models, but were detected by the robust algorithm and excluded to retrieve the true model. An application of the robust inversion algorithm to the field data demonstrates that the method is useful for data clean-up of outliers, which could include model as well as data inconsistency (for example, inability to fit a 2-D model to a 3-D data set), during inversion and for objectively obtaining a robust and optimal model. The present statistical method is available irrespective of the dimensionality of target structures (hence 2-D and 3-D structures) and of isotropy or anisotropy, and can operate as an external process to any inversion algorithm without modifications to the inversion program.
Kinematic and dynamic synergies of human precision-grip movements.
Grinyagin, I V; Biryukova, E V; Maier, M A
2005-10-01
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
Pythagoras Theorem and Relativistic Kinematics
NASA Astrophysics Data System (ADS)
Mulaj, Zenun; Dhoqina, Polikron
2010-01-01
In two inertial frames that move in a particular direction, may be registered a light signal that propagates in an angle with this direction. Applying Pythagoras theorem and principles of STR in both systems, we can derive all relativistic kinematics relations like the relativity of simultaneity of events, of the time interval, of the length of objects, of the velocity of the material point, Lorentz transformations, Doppler effect and stellar aberration.
NASA Astrophysics Data System (ADS)
Ólafsson, Haraldur; Líf Kristinsdóttir, Birta; Ágústsson, Hálfdán; Opsanger Jonassen, Marius; Jónsson, Sigurður
2015-04-01
Inversions are known to be important for the structure and magnitude of orographic flow disturbances. Several observational and numerical evidence of the impact of inversions is presented, ranging from gravity waves with extreme rotors to weak mountain flow. A preliminary attempt to map the climatology of inversions in Iceland is also presented. The above studies indicate that elements of the flow may be very sensitive to not only the elevation, but also the strength or sharpness of the inversion. A temperature change of less than 2 K at the inversion may transform the downstream flow pattern, leading to an increased magnitude of vertical velocities by an order of magnitude, up to tens of m/s. Numerical weather prediction models tend to fail in reproduction of the inversions.
"Nonrelativistic" kinematics: Particles or waves?
Jens Madsen Houlrik; Germain Rousseaux
2010-05-11
The kinematics of particles refer to events and tangent vectors, while that of waves refer to dual gradient planes. Special relativity [1-3] applies to both objects alike. Here we show that spacetime exchange symmetry [7] implicit in the SIdefinition of length based on the universal constant c has profound consequences at low velocities. Galilean physics, exact in the limit c \\to \\infty, is mirrored by a dual so-called Carrollian superluminal kinematics [4-6] exact in the limit c \\to 0. Several new results follow. The Galilean limit explains mass conservation in Newtonian mechanics, while the dual limit is a kinematical prerequisite for wavelike tachyonic motion [8, 9]. As an example, the Land\\'e paradox [19, 20] of waveparticle duality has a natural resolution within special relativity in terms of superluminal, particlelike waves. It is emphasized that internal particle energy mc^2 can not be ignored, while kinetic energy leads to an extended Galilei group. We also demonstrate that Maxwell's equations have magnetic and electric limits covariant under Galilean and Carrollian symmetry.
CME -CME interaction: Kinematics & Consequences
NASA Astrophysics Data System (ADS)
Srivastava, Nandita; Mishra, Wageesh
2015-04-01
The launch of STEREO spacecraft with the capability of heliospheric imaging alongwith in-situ observations have provided us an opportunity to track and understand the propagation of CMEs from the Sun to the Earth and beyond. We present the results of a study based on several cases of CME-CME interaction observed by STEREO/HI instruments. These CMEs were launched in quick succession and interacted as they propagated in the inner heliosphere. We estimate the 3D kinematics of these interacting CMEs using stereoscopic observations and examine the nature of their collision /interaction and exchange of momentum during interaction. We also compare the actual arrival times of these CMEs with that estimated from the 3D kinematics. This would help us to understand the role of the post-collision kinematics dependence on the actual arrival time of these CMEs at the in-situ spacecraft. Further, we examine the signatures of collision/interaction of CMEs in in-situ observations. The consequences of interaction in strengthening the geoeffectiveness of CMEs will also be presented.
MEERSCHAERT, MARK M.; STRAKA, PETER
2013-01-01
The inverse stable subordinator provides a probability model for time-fractional differential equations, and leads to explicit solution formulae. This paper reviews properties of the inverse stable subordinator, and applications to a variety of problems in mathematics and physics. Several different governing equations for the inverse stable subordinator have been proposed in the literature. This paper also shows how these equations can be reconciled. PMID:25045216
Inversion of high frequency surface waves with fundamental and higher modes
Xia, J.; Miller, R.D.; Park, C.B.; Tian, G.
2003-01-01
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.
Development of a sensor coordinated kinematic model for neural network controller training
NASA Technical Reports Server (NTRS)
Jorgensen, Charles C.
1990-01-01
A robotic benchmark problem useful for evaluating alternative neural network controllers is presented. Specifically, it derives two camera models and the kinematic equations of a multiple degree of freedom manipulator whose end effector is under observation. The mapping developed include forward and inverse translations from binocular images to 3-D target position and the inverse kinematics of mapping point positions into manipulator commands in joint space. Implementation is detailed for a three degree of freedom manipulator with one revolute joint at the base and two prismatic joints on the arms. The example is restricted to operate within a unit cube with arm links of 0.6 and 0.4 units respectively. The development is presented in the context of more complex simulations and a logical path for extension of the benchmark to higher degree of freedom manipulators is presented.
The Maximal Kinematical Invariance Group of Fluid Dynamics and Explosion–Implosion Duality
L. O'Raifeartaigh; V. V. Sreedhar
2001-01-01
It has recently been found that supernova explosions can be simulated in the laboratory by implosions induced in a plasma by intense lasers. A theoretical explanation is that the inversion transformation, (?:t??1\\/t, x?x\\/t), leaves the Euler equations of fluid dynamics, with standard polytropic exponent, invariant. This implies that the kinematical invariance group of the Euler equations is larger than the
Optimal Trajectory Planning for Wheeled Mobile Robots Based on Kinematics Singularity
Luis Gracia; Josep Tornero
2008-01-01
This research introduces a new optimality criterion for motion planning of wheeled mobile robots based on a cost index that assesses the nearness to singularity of forward and\\u000a inverse kinematic models. Slip motions, infinite estimation error and impossible control actions are avoided escaping from singularities. In addition, high amplification of wheel velocity errors and high wheel velocity values are\\u000a also
NASA Astrophysics Data System (ADS)
Lu, Qipeng; Li, Yongjun; Peng, Zhongqi
2012-05-01
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.
Abel inversion: optical preprocessing
Igor V. Markhvida; Ludmila V. Chvyaleva; Pavel Sumin
1997-01-01
The Abel inversion is a tomographic problem which we meet in a wide range of areas from astronomy, plasma and jet research to cell microscopy. The Abel inversion restores a radial distribution of refractive index, absorption index or other values for axial symmetric objects. It uses derivative operation that is why the theoretical solving is incorrect. Complex mathematical methods are
JULIAN TUDOR HART
care tends to vary inversely with the need for it in the population served. This inverse care law operates more completely where medical care is most exposed to market forces, and less so where such exposure is reduced. The market distribution of medical care is a primitive and historically outdated social form, and any return to it would further exag-
Algebra Lab: Inverse Variation
NSDL National Science Digital Library
2012-01-01
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.
ERIC Educational Resources Information Center
Bedard, Catherine; Belin, Pascal
2004-01-01
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…
Inverse Lighting for Photography
Donald P. Greenberg; Stephen R. Marschner
1997-01-01
We introduce a technique for improving photographs using inverse lighting, a new process based on algorithms developed in computer graphics for computing the reflection of light in 3D space. From a photograph and a 3D surface model for the object pictured, inverse lighting estimates the directional distribution of the incident light. We then use this information to process the photograph
Auditory filter bank inversion
L. Lin; W. H. Holines; Eliathamby Ambikairajah
2001-01-01
Models of auditory filtering using the Gammatone filter bank are useful tools in speech processing. A perceptually accurate auditory inversion model has applications in speech and audio coding. This paper proposes a new auditory filter bank inversion method using a least squares optimization technique. The proposed method is computationally efficient and its low delay makes it suitable for frame-by-frame processing.
NASA Astrophysics Data System (ADS)
Pearson, Bruce R.; van de Water, Willem
2005-03-01
While the ordinary structure function in turbulence is concerned with the statistical moments of the velocity increment ?u measured over a distance r , the inverse structure function is related to the distance r where the turbulent velocity exits the interval ?u . We study inverse structure functions of wind-tunnel turbulence which covers a range of Reynolds numbers Re?=400-1100 . We test a recently proposed relation between the scaling exponents of the ordinary structure functions and those of the inverse structure functions [S. Roux and M. H. Jensen, Phys. Rev. E 69, 16309 (2004)]. The relatively large range of Reynolds numbers in our experiment also enables us to address the scaling with Reynolds number that is expected to highlight the intermediate dissipative range. While we firmly establish the (relative) scaling of inverse structure functions, our experimental results fail both predictions. Therefore, the question of the significance of inverse structure functions remains open.
NASA Astrophysics Data System (ADS)
Stoica, Alin; Pisla, Doina; Andras, Szilaghyi; Gherman, Bogdan; Gyurka, Bela-Zoltan; Plitea, Nicolae
2013-03-01
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.
Kinematics in Vector Boson Fusion
D. Green
2006-03-02
The vector boson fusion process leads to two forward/backward jets (tag jets) and the produced state, a Higgs boson in this case, moving slowly in the p-p C.M. frame at the LHC. For the case of Higgs decaying to W+W (W*) with Higgs mass below 180 GeV, the W bosons have low momentum in the Higgs C.M. For the case of W leptonic decays, this fact allows for an approximate reconstruction of the two final state neutrinos. In turn, those solutions then provide additional kinematic cuts against background.
Kinematics of evaporating black holes
Vilkovisky, G.A. [Lebedev Physical Institute and Lebedev Research Center in Physics, Leninsky Prospect 53, 119991 Moscow (Russian Federation)]. E-mail: vilkov@sci.lebedev.ru
2006-12-15
The correspondence principle and causality divide the spacetime of a macroscopic collapsing mass into three regions: classical, semiclassical, and ultraviolet. The semiclassical region covers the entire evolution of the black hole from the macroscopic to the microscopic scale if the latter is reached. It is shown that the metric in the semiclassical region is expressed purely kinematically through the Bondi charges. The only quantum calculation needed is the one of radiation at infinity. The ultraviolet ignorance of semiclassical theory is irrelevant. The metric with arbitrary Bondi charges is obtained and studied.
Ensemble Modeling of Kinematic Open Channel Flow
NASA Astrophysics Data System (ADS)
Ercan, A.; Kavvas, M. L.
2012-12-01
In this study, stochastic modeling of kinematic open channel flow is performed. Nonlocal Lagrangian-Eulerian Fokker-Planck Equation of the kinematic open channel flow process under uncertain channel properties and lateral flow is developed utilizing the stochastic method of characteristics. Monte Carlo simulations applied to two numerical test problems showed that the developed Fokker-Planck equation is capable of modeling ensemble behavior of the kinematic open channel flow process.
Kinematic features of wheelchair propulsion.
Sanderson, D J; Sommer, H J
1985-01-01
Three male paraplegics volunteered to push their wheelchairs on a motor driven treadmill, for a total of 80 min each, at a work rate of 60-65% of their VO2 maximum, determined on an earlier test session. At 20 min intervals 16 mm high-speed film of the subjects was taken for three consecutive push cycles. The digitized film was used to compute the angular kinematics of the shoulder and elbow joints, the variations in the position of the trunk (as measured by a marker on the neck) and hand relative to the axle of the rear wheel. There were no intrasubject variations over the 80 min testing period for any of the recorded variables. This was interpreted as implying that at that work rate, fatigue was not exhibited as variations in the kinematics of movement. There were considerable differences between the style of one subject when compared to the other two over all the trials of each subject. This variation in style was most obvious in subject number PT who had a pumping style of push and recovery whereas subjects CA and GW employed a more continuous circular motion. The differences in the amount of forward lean of each subject were related to residual muscle strength. The discussion centered on the influence of the different styles on performance. PMID:4030799
Ballistic representation for kinematic access
NASA Astrophysics Data System (ADS)
Alfano, Salvatore
2011-01-01
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.
Ajay Verma; Kamesh Subbarao; John L. Junkins
2000-01-01
Structured adaptive model inversion is used for designing adaptive flight control laws to track a target reference trajectory for autonomous UAVs. The mathematical model of the plant is refined by incorporating the known structured kinematic nonlinearities arising out of the gyroscopic coupling and the Coriolis terms thereby rendering the plant to have an “almost” exact nonlinear structure. For the aircraft
Instituto de Sistemas e Robotica
An Online Algorithm for Simultaneously Learning Forward and Inverse Kinematics Bruno Damas and Jos´e Santos-Victor Abstract-- This paper proposes a supervised algorithm for online learning of input is an incre- mental, online and localized learning algorithm that performs nonlinear, multivariate regression
O. H. Frankel
1937-01-01
Summary 1. In twenty-two species ofFritillaria no evidence of inversions has been found.\\u000a \\u000a 2. In the following species, viz.F. dasyphylla 2x, F. dasyphylla 3x, F. pudica 3x, F. citrina andF. recurva 3x, the results of crossing-over in inversions have been observed.\\u000a \\u000a \\u000a \\u000a 3. InversionA inF. dasyphylla 2x, located at, or near, the distal end of anS bivalent, has a frequency of about
Speeding up the learning of robot kinematics through function decomposition.
Ruiz de Angulo, Vicente; Torras, Carme
2005-11-01
The main drawback of using neural networks or other example-based learning procedures to approximate the inverse kinematics (IK) of robot arms is the high number of training samples (i.e., robot movements) required to attain an acceptable precision. We propose here a trick, valid for most industrial robots, that greatly reduces the number of movements needed to learn or relearn the IK to a given accuracy. This trick consists in expressing the IK as a composition of learnable functions, each having half the dimensionality of the original mapping. Off-line and on-line training schemes to learn these component functions are also proposed. Experimental results obtained by using nearest neighbors and parameterized self-organizing map, with and without the decomposition, show that the time savings granted by the proposed scheme grow polynomially with the precision required. PMID:16342491
Geological Inverse Theory Resources
NSDL National Science Digital Library
Ganse, Andrew A.
This website from Andrew A. Ganse of the University of Washington's Applied Physics Laboratory includes a list of resources on geophysical inverse theory. It includes introductory material, textbooks, papers, web resources, lab lecture notes and more.
Inverse problems in electromagnetics
Chen, Xudong, 1977-
2005-01-01
Two inverse problems in electromagnetics are investigated in this thesis. The first is the retrieval of the effective constitutive parameters of metamaterials from the measurement of the reflection and the transmission ...
Borehole Resistivity Inversion
Garipova, Yulia V.
1997-01-01
In this paper we perform the inversion of borehole resistivity data using the software package developed by Western Atlas Logging Services, Houston, TX. Direct current resistivity methods, namely lateral sounding and ...
Wang, Fang
2014-06-26
of inverse problems, namely the reconstructions of the parameters, may not exist, may not be unique or may be unstable. Regularization is a technique that deals with such situations. The well-known Tikhonov regularization method translates the original...
Pant-tilt Platform Design Based on Parallel Kinematics
NASA Astrophysics Data System (ADS)
Majarena, A. C.; Santolaria, J.; Aguilar, J. J.; Pastor, J.; Cajal, Cajal
2009-11-01
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.
A Kinematically Consistent Two-Point Correlation Function
NASA Technical Reports Server (NTRS)
Ristorcelli, J. R.
1998-01-01
A simple kinematically consistent expression for the longitudinal two-point correlation function related to both the integral length scale and the Taylor microscale is obtained. On the inner scale, in a region of width inversely proportional to the turbulent Reynolds number, the function has the appropriate curvature at the origin. The expression for two-point correlation is related to the nonlinear cascade rate, or dissipation epsilon, a quantity that is carried as part of a typical single-point turbulence closure simulation. Constructing an expression for the two-point correlation whose curvature at the origin is the Taylor microscale incorporates one of the fundamental quantities characterizing turbulence, epsilon, into a model for the two-point correlation function. The integral of the function also gives, as is required, an outer integral length scale of the turbulence independent of viscosity. The proposed expression is obtained by kinematic arguments; the intention is to produce a practically applicable expression in terms of simple elementary functions that allow an analytical evaluation, by asymptotic methods, of diverse functionals relevant to single-point turbulence closures. Using the expression devised an example of the asymptotic method by which functionals of the two-point correlation can be evaluated is given.
Kinematics of the foot during slips
April J. Chambers; Raki ´ e Chama
Slip and fall accidents are often listed among the leading generators of injuries. The goals of this study were to (1) describe the foot kinematics during unexpected slips, and (2) to compare the foot kinematics during gait in unexpected slippery environment and when warnings of slippery environments are provided. Five participants walked on dry and glycerol- contaminated floors, while varying
Approximating Kinematics for Tracked Mobile Robots
J. L. Martínez; A. Mandow; J. Morales; S. Pedraza; A. García-Cerezo
2005-01-01
In this paper we propose a kinematic approach for tracked mobile robots in order to improve motion control and pose estimation. Complex dynamics due to slippage and track–soil interactions make it difficult to predict the exact motion of the vehicle on the basis of track velocities. Nevertheless, real-time computations for autonomous navigation require an effective kinematics approximation without introducing dynamics
Control Algorithms For Kinematically Redundant Manipulators
NASA Technical Reports Server (NTRS)
Wegner, David R.
1995-01-01
Report presents improved algorithms for controlling kinematically redundant robotic manipulators, producing unique configuration for each end-effector location. Furthermore, they generally produce configurations in which no interference between robot boom and payload or base structures. Report presents comparison between various other robot-kinematic algorithms.
Is precession electron diffraction kinematical? Part II
A. S. Eggeman; T. A. White; P. A. Midgley
2010-01-01
A series of experiments was undertaken to investigate the kinematical nature of precession electron diffraction data and to gauge the optimum precession angle for a particular system. Kinematically forbidden reflections in silicon were used to show how a large precession angle is needed to minimise multi-beam conditions for specific reflections and so reduce the contribution from dynamical diffraction. Small precession
Kinematic Event Patterns in Speech: Special Problems.
ERIC Educational Resources Information Center
Westbury, John R.; Severson, Elizabeth J.; Lindstrom, Mary J.
2000-01-01
Results from a new analysis of synchronous acoustic and fleshpoint-kinematic data, recorded from 53 normal young-adult speakers of American English, are reported. The kinematic data represent speech-related actions of the tongue blade and dorsum, both lips, and the mandible, during the test words, "special" and "problem," and were drawn from an…
FORWARD KINEMATICS: THE DENAVIT-HARTENBERG
Baltes, Jacky
rise to a universal language with which robot engineers can communicate. A robot manipulator with n the forward or configuration kinematic equations for rigid robots. The forward kinematics problem is concerned with the relationship between the individual joints of the robot manipulator and the position and orientation
In vivo kinematic measurement during laparoscopic cholecystectomy
M. Rasmus; R. Riener; S. Reiter; A. Schneider; H. Feussner
2004-01-01
Background: Despite the rapid development of computer-assisted surgery, studies on kinematic measurement for surgical innovation are rare. This study describes a system for kinematic measurement in real operating theater environments. Six laparoscopic cholecystectomies were recorded and analyzed. In addition to a demonstration of the feasibility of the method, basis data for the development of an actuated laparoscopic camera holder are
Target tracking problems subject to kinematic constraints
MINJEA TAHK; JASON L. SPEYER
1990-01-01
Filtering problems with kinematic constraints which may arise in target tracking problems are considered. A novel approach which treats kinematic constraints as additional fictitious or pseudomeasurements is proposed. A numerical example is provided to show the technical feasibility of the proposed idea for target tracking problems. This example shows that the proposed method can improve estimation accuracy significantly for velocity
The kinematic effects on the rotation curve
Chongming Xu; Xuejun Wu
1988-01-01
In this paper, it is pointed out that if the spiral galaxies as a whole revolve about some common center, the rotation curve will be changed by the kinematic effects. The common center could be the center of a supercluster or the center of dark matter and luminous matter. The kinematic effects on the rotation curve are calculated. The additional
The inverse electroencephalography pipeline
NASA Astrophysics Data System (ADS)
Weinstein, David Michael
The inverse electroencephalography (EEG) problem is defined as determining which regions of the brain are active based on remote measurements recorded with scalp EEG electrodes. An accurate solution to this problem would benefit both fundamental neuroscience research and clinical neuroscience applications. However, constructing accurate patient-specific inverse EEG solutions requires complex modeling, simulation, and visualization algorithms, and to date only a few systems have been developed that provide such capabilities. In this dissertation, a computational system for generating and investigating patient-specific inverse EEG solutions is introduced, and the requirements for each stage of this Inverse EEG Pipeline are defined and discussed. While the requirements of many of the stages are satisfied with existing algorithms, others have motivated research into novel modeling and simulation methods. The principal technical results of this work include novel surface-based volume modeling techniques, an efficient construction for the EEG lead field, and the Open Source release of the Inverse EEG Pipeline software for use by the bioelectric field research community. In this work, the Inverse EEG Pipeline is applied to three research problems in neurology: comparing focal and distributed source imaging algorithms; separating measurements into independent activation components for multifocal epilepsy; and localizing the cortical activity that produces the P300 effect in schizophrenia.
Relating tolerances and kinematic behavior
NASA Astrophysics Data System (ADS)
Bourne, D. A.; Navinchandra, D.; Ramaswamy, R.
1989-04-01
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.
Kinematic model of southern California
Weldon, R.; Humphreys, E.
1986-02-01
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.
Non-linear traveltime inversion for 3-D seismic tomography in strongly anisotropic media
NASA Astrophysics Data System (ADS)
Zhou, Bing; Greenhalgh, Stewart
2008-01-01
We have developed two, new non-linear traveltime inversion schemes for 3-D seismic tomography in anisotropic media. They differ from the traditional linearized inversion approach and offer five significant improvements: (1) they are based on an alternative form of the first-order traveltime perturbation equation, derived so as to simplify the inversion formulae and overcome the quasi shear wave singularity problem; (2) robust 3-D ray tracing is employed which enables the simultaneous computation of the first-arrival traveltimes and ray paths for the three body waves (qP, qS1 and qS2) in arbitrary anisotropic media; (3) the Jacobian matrix used in the update is based on an efficient computation for a 3-D anisotropic model, so that the inversion is applicable to both weakly and strongly anisotropic situations, unlike most previous approaches which assume weak anisotropy; (4) a local-search, constrained minimization is applied to the non-linear inversion which makes anisotropic tomographic imaging an iterative procedure; (5) there is an option to invert for the elastic moduli directly or the Thomsen parameters directly in heterogenous, tilted transversely isotropic media, using any source-receiver recording geometry. We have examined the imaging capability of the non-linear solver with individual body-wave modes using a 3-D synthetic anisotropic model incorporating two targets, a `high velocity' and a `low velocity' anomaly, embedded in a titled transversely isotropic medium. The model is illuminated by means of azimuthal VSP and crosshole measurements. The experimental results show that the two non-linear inversion schemes successfully image the `targets' and yield satisfactory 3-D tomograms of the elastic moduli and the Thomsen parameters.
Relativistic kinematics beyond Special Relativity
J. M. Carmona; J. L. Cortes; F. Mercati
2012-09-28
In the context of departures from Special Relativity written as a momentum power expansion in the inverse of an ultraviolet energy scale M, we derive the constraints that the relativity principle imposes between coefficients of a deformed composition law, dispersion relation, and transformation laws, at first order in the power expansion. In particular, we find that, at that order, the consistency of a modification of the energy-momentum composition law fixes the modification in the dispersion relation. We therefore obtain the most generic modification of Special Relativity that preserves the relativity principle at leading order in 1/M.
NASA Technical Reports Server (NTRS)
Bayo, Eduardo; Ledesma, Ragnar
1993-01-01
A technique is presented for solving the inverse dynamics of flexible planar multibody systems. This technique yields the non-causal joint efforts (inverse dynamics) as well as the internal states (inverse kinematics) that produce a prescribed nominal trajectory of the end effector. A non-recursive global Lagrangian approach is used in formulating the equations for motion as well as in solving the inverse dynamics equations. Contrary to the recursive method previously presented, the proposed method solves the inverse problem in a systematic and direct manner for both open-chain as well as closed-chain configurations. Numerical simulation shows that the proposed procedure provides an excellent tracking of the desired end effector trajectory.
Kinematic modeling of folding above listric propagating thrusts
NASA Astrophysics Data System (ADS)
Cardozo, Nestor; Brandenburg, J. P.
2014-03-01
We describe a kinematic approach to simulate folds above listric propagating thrusts. The model is based on a pre-defined circular thrust geometry with a maximum central angle beyond which the thrust is planar, inclined shear above the circular thrust, and trishear in front of the thrust. Provided the trajectory of thrust propagation is established, the model can be run forward and backwards. We use this last feature to implement a global simulated annealing, inverse modeling strategy. This inverse modeling strategy is applied to synthetic folds as well as two real examples in offshore Venezuela and the Niger Delta toe-thrust system. These three examples illustrate the benefits of the algorithm, particularly in predicting the possible range of models that can fit the structures. Thrust geometry, depth to detachment level, and backlimb geometry have high impact in model parameters such as backlimb shear angle and fault slip; while forelimb geometry is critical to constrain parameters such as fault propagation to fault slip ratio and trishear angle. Steep to overturned beds in forelimb areas are often not imaged by seismic, so in the absence of additional well data, considering all possible thrust-fold geometries is critical for the modeling and whatever prediction (e.g. hydrocarbon trap integrity) is made from it.
Estimation of near-surface shear-wave velocity by inversion of Rayleigh waves
Xia, J.; Miller, R.D.; Park, C.B.
1999-01-01
The shear-wave (S-wave) velocity of near-surface materials (soil, rocks, pavement) and its effect on seismic-wave propagation are of fundamental interest in many groundwater, engineering, and environmental studies. Rayleigh-wave phase velocity of a layered-earth model is a function of frequency and four groups of earth properties: P-wave velocity, S-wave velocity, density, and thickness of layers. Analysis of the Jacobian matrix provides a measure of dispersion-curve sensitivity to earth properties. S-wave velocities are the dominant influence on a dispersion curve in a high-frequency range (>5 Hz) followed by layer thickness. An iterative solution technique to the weighted equation proved very effective in the high-frequency range when using the Levenberg-Marquardt and singular-value decomposition techniques. Convergence of the weighted solution is guaranteed through selection of the damping factor using the Levenberg-Marquardt method. Synthetic examples demonstrated calculation efficiency and stability of inverse procedures. We verify our method using borehole S-wave velocity measurements.Iterative solutions to the weighted equation by the Levenberg-Marquardt and singular-value decomposition techniques are derived to estimate near-surface shear-wave velocity. Synthetic and real examples demonstrate the calculation efficiency and stability of the inverse procedure. The inverse results of the real example are verified by borehole S-wave velocity measurements.
S. N. Storchak
2008-10-31
The geometrical representation of the path integral reduction Jacobian obtained in the problem of the path integral quantization of a scalar particle motion on a smooth compact Riemannian manifold with the given free isometric action of the compact semisimple Lie group has been found for the case when the local reduced motion is described by means of dependent coordinates. The result is based on the scalar curvature formula for the original manifold which is viewed as a total space of the principal fibre bundle.
Kinematic determinants of human locomotion.
Borghese, N A; Bianchi, L; Lacquaniti, F
1996-01-01
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 PMID:8865081
Reducing Nonuniqueness in Finite Source Inversion Using Rotational Ground Motions
NASA Astrophysics Data System (ADS)
Bernauer, M.; Fichtner, A.; Igel, H.
2014-12-01
We assess the potential of rotational ground motion recordings to reduce nonuniqueness in kinematic source inversions, with emphasis on the required measurement accuracy of currently developed rotation sensors. Our analysis is based on synthetic Bayesian finite source inversions that avoid linearizations and provide a comprehensive quantification of uncertainties and trade-offs. Using the fault and receiver geometry of the Tottori 2000 earthquake as a testbed, we perform inversions for two scenarios: In scenario I, we use translational velocity recordings only. In scenario II, we randomly replace half of the velocity recordings by rotation recordings, thus keeping the total amount of data constant. To quantify the noise-dependent impact of rotation recordings, we perform a sequence of inversions with varying noise levels of rotations relative to translations. Our results indicate that the incorporation of rotational ground motion recordings can significantly reduce nonuniqueness in finite source inversions, provided that measurement uncertainties are similar to or below the uncertainties of translational velocity recordings. When this condition is met, rupture velocity and rise time benefit most from rotation data. The trade-offs between both parameters are then strongly reduced, and the information gain nearly doubles. This suggests that rotational ground motion recordings may improve secondary inferences that rely on accurate information about rise time and rupture velocity. These include frictional properties of the fault, radiation directivity and ground motion in general.
Inverse and forward numerical modeling of trishear fault-propagation folds
NASA Astrophysics Data System (ADS)
Allmendinger, Richard W.
1998-08-01
Fault-propagation folds commonly display footwall synclines as well as changes in stratigraphic thickness and dip on their forelimbs, features that cannot easily be explained by simple parallel kink fold kinematics. An alternative kinematic model, trishear, can explain these observations, as well as a variety of other features which have long intrigued structural geologists. Trishear has received little attention until recently, in part because it must be applied numerically rather than graphically. A new computer program has been developed to analyze trishear and hybrid trishear-fault-bend fold deformation. Trishear fold shape can vary considerably by changing the apical angle of the trishear zone and/or the propagation to slip ratio (P/S) during the evolution of the structure. Breakouts, anticlinal and synclinal ramps, and inversion structures can also be modeled, tracking the kinematics with growth strata. Strain within trishear zones can be used to predict fracture orientations throughout the structures as demonstrated by comparison with analog clay models. Also presented is a method for inverting data on real structures for a best fit trishear model by performing a grid search over a six-parameter space (ramp angle, trishear apical angle, displacement, P/S, and X and Y positions of the fault tip line). The inversion is performed by restoring a key bed to a planar orientation by least squares regression. Because trishear provides a bulk kinematic description of a deforming zone, it is complementary to, rather than competing with, other kinematic models.
Kinematical Uniqueness of Loop Quantum Gravity
Fleischhack, Christian
2015-01-01
We review uniqueness results for the kinematical part of loop quantum gravity. After sketching the general loop formalism, the holonomy-flux and the Weyl algebras are introduced. In both cases, then, diffeomorphism invariant representations are described.
Kinematical Uniqueness of Loop Quantum Gravity
Christian Fleischhack
2015-05-17
We review uniqueness results for the kinematical part of loop quantum gravity. After sketching the general loop formalism, the holonomy-flux and the Weyl algebras are introduced. In both cases, then, diffeomorphism invariant representations are described.
Kinematical coincidence method in transfer reactions
NASA Astrophysics Data System (ADS)
Acosta, L.; Amorini, F.; Auditore, L.; Berceanu, I.; Cardella, G.; Chatterjiee, M. B.; De Filippo, E.; Francalanza, L.; Gianì, R.; Grassi, L.; Grzeszczuk, A.; La Guidara, E.; Lanzalone, G.; Lombardo, I.; Loria, D.; Minniti, T.; Pagano, E. V.; Papa, M.; Pirrone, S.; Politi, G.; Pop, A.; Porto, F.; Rizzo, F.; Rosato, E.; Russotto, P.; Santoro, S.; Trifirò, A.; Trimarchi, M.; Verde, G.; Vigilante, M.
2013-07-01
A new method to extract high resolution angular distributions from kinematical coincidence measurements in binary reactions is presented. Kinematics is used to extract the center of mass angular distribution from the measured energy spectrum of light particles. Results obtained in the case of 10Be+p?9Be+d reaction measured with the CHIMERA detector are shown. An angular resolution of few degrees in the center of mass is obtained. The range of applicability of the method is discussed.
Regge kinematics in soft collinear effective theory
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
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.
In vivo kinematic measurement during laparoscopic cholecystectomy
M. Rasmus; R. Riener; S. Reiter; A. Schneider; H. Feussner I
2004-01-01
Background Despite the rapid development of computer-assisted surgery, studies on kinematic measurement for surgical innovation are rare.\\u000a This study describes a system for kinematic measurement in real operating theater environments. Six laparoscopic cholecystectomies\\u000a were recorded and analyzed. In addition to, a demonstration of the feasibility of the method, basis data for the development\\u000a of an actuated laparoscopic camera holder are evaluated.
Kinematics of tt¯ events at CDF
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
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
Statistical Methods for Estimation of Direct and Differential Kinematics of the Vocal Tract
Lammert, Adam; Goldstein, Louis; Narayanan, Shrikanth; Iskarous, Khalil
2012-01-01
We present and evaluate two statistical methods for estimating kinematic relationships of the speech production system: Artificial Neural Networks and Locally-Weighted Regression. The work is motivated by the need to characterize this motor system, with particular focus on estimating differential aspects of kinematics. Kinematic analysis will facilitate progress in a variety of areas, including the nature of speech production goals, articulatory redundancy and, relatedly, acoustic-to-articulatory inversion. Statistical methods must be used to estimate these relationships from data since they are infeasible to express in closed form. Statistical models are optimized and evaluated – using a heldout data validation procedure – on two sets of synthetic speech data. The theoretical and practical advantages of both methods are also discussed. It is shown that both direct and differential kinematics can be estimated with high accuracy, even for complex, nonlinear relationships. Locally-Weighted Regression displays the best overall performance, which may be due to practical advantages in its training procedure. Moreover, accurate estimation can be achieved using only a modest amount of training data, as judged by convergence of performance. The algorithms are also applied to real-time MRI data, and the results are generally consistent with those obtained from synthetic data. PMID:24052685
NASA Astrophysics Data System (ADS)
Clare, R. B.; Levinger, J. S.
1981-02-01
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.
W. P. Chu; M. P. McCormick; J. Lenoble; C. Brogniez; P. Pruvost
1989-01-01
The operational Stratospheric Aerosol and Gas Experiment II multichannel data inversion algorithm is described. Aerosol and ozone retrievals obtained with the algorithm are discussed. The algorithm is compared to an independently developed algorithm (Lenoble, 1989), showing that the inverted aerosol and ozone profiles from the two algorithms are similar within their respective uncertainties.
Inverses and Elementary Matrices
NSDL National Science Digital Library
Smith, David
Created by David Smith for the Connected Curriculum Project, 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. This is part of a larger collection of learning modules hosted by Duke University.
Inverse problem in optical diffusion tomography. IV. Nonlinear inversion formulas
Vadim A. Markel; Joseph A. O’Sullivan; John C. Schotland
2003-01-01
We continue our study of the inverse scattering problem for diffuse light. In contrast to our earlier work, in which we considered the linear inverse problem, we now consider the nonlinear problem. We obtain a solution to this problem in the form of a functional series expansion. The first term in this expansion is the pseudo- inverse of the linearized
Kinematics of the Danakil microplate
NASA Astrophysics Data System (ADS)
Eagles, Graeme; Gloaguen, Richard; Ebinger, Cynthia
2002-10-01
A refinement and extrapolation of recent motion estimates for the Danakil microplate, based on ancient kinematic indicators in the Afar region, describes the evolution of a microplate in the continental realm. The Danakil horst is an elevated part of this microplate, exposing a Precambrian basement within the Afar depression, the site of the Nubia-Somalia-Arabia triple junction. We compare evidence for strike- or oblique-slip faults in data from the Afar depression and southern Red Sea to small circles about published poles of rotation for the Danakil microplate with respect to Nubia. A reconstruction about the preferred pole reunites lengths of a Precambrian shear zone on the Nubia and Danakil sides and preserves a uniform basement fabric strike through Nubia, Danakil and Yemen. Since at least magnetic chron C5 (˜11 Ma) Danakil rotated about a different pole with respect to Nubia than either Somalia or Arabia, but between chrons C5 and C2A Nubia-Danakil motion was a close approximation to Nubia-Somalia motion. Since C2A relative motions of the Danakil microplate have been independent of movements on any of the neighbouring plate boundaries. We relate this to the onset of oceanic-type accretion within Afar. The resulting eastwards acceleration of Danakil was accommodated by westwards propagation of the Gulf of Aden rift that became the new, discrete, plate boundary between the Danakil microplate and the Somalia plate. Present-day activity suggests that the Red Sea and Aden rifts will link through Afar, thereby isolating the Danakil horst as a microcontinent on the Arabian margin.
NASA Technical Reports Server (NTRS)
Hennessey, Michael P.; Huang, Paul C.; Bunnell, Charles T.
1989-01-01
An efficient approach to cartesian motion and force control of a 7 degree of freedom (DOF) manipulator is presented. It is based on extending the active stiffness controller to the 7 DOF case in general and use of an efficient version of the gradient projection technique for solving the inverse kinematics problem. Cooperative control is achieved through appropriate configuration of individual manipulator controllers. In addition, other aspects of trajectory generation using standard techniques are integrated into the controller. The method is then applied to a specific manipulator of interest (Robotics Research T-710). Simulation of the kinematics, dynamics, and control are provided in the context of several scenarios: one pertaining to a noncontact pick and place operation; one relating to contour following where contact is made between the manipulator and environment; and one pertaining to cooperative control.
a Six-Link Kinematic Chain Model of Human Body Using Kane's Method
NASA Astrophysics Data System (ADS)
Rambely, A. S.; Fazrolrozi
A biomechanics model of six-link kinematic chain of human body is developed by using Kane's method. The kinematic data comprise of six segments; foot, calf, thigh, trunk, upper arm and forearm, are obtained through data collection of walking, running and jumping using the Vicon Nexus system. The motion capture system uses 12 Vicon MX-3+ cameras and 12 Vicon MX-F40 cameras, two DV (50 Hz) cameras and a force plate (100 Hz). Inverse dynamics approach is used to obtain the unknown value of torques produced by joint segments during walking, running and jumping activities. The results show that the largest value of torques produced occurs at the foot segment.
Inverse Problems in Wave Scattering
Martin Hanke-Bourgeois; Andreas Kirsch; William Rundell
2007-01-01
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.
Modular Inverse Algorithms without Multiplications
Laszlo Hars
2004-01-01
the basic left-shift, right-shift and shifting Euclidean modular inverse algorithms are presented with new optimization tricks. These algorithms are based on the corresponding extended GCD algorithms, but only one multiplicator, the modular inverse is computed. On many computational platforms, for operand lengths used in cryptography, the fastest modular inverse algorithms need about twice the modular multiplication time, or even less.
Inverse Problems in Systems Biology
Fulmek, Markus
Inverse Problems in Systems Biology Heinz W.Engl Johann Radon Institute for Computational.W. Engl, C. Flamm, P. K¨ugler, J. Lu, S. M¨uller and P. Schuster, Inverse problems in systems biology, Inverse Problems 25 (2009) 1 #12;Systems biology is a relatively young biological discipline that claims
INVERSE PROTEIN FOLDING, HIERARCHICAL OPTIMISATION
Halligan, Daniel
INVERSE PROTEIN FOLDING, HIERARCHICAL OPTIMISATION AND TIE KNOTS Thomas M. A. Fink st. john Introduction 3 1.1 Inverse Protein Folding 3 1.2 Hierarchical Optimisation 5 1.3 Tie Knots 6 1.4 Schematic Organisation 6 1.5 Publications 9 2 Protein Folding, Inverse Protein Folding and Energy Landscapes 10 2
Inverse avalanches on Abelian sandpiles
Chau, H.F. (School of Natural Sciences, Institute for Advanced Study, Olden Lane, Princeton, New Jersey 08540 (United States) Department of Physics, University of Illinois at Urbana-Champaign, 1110 West Green Street, Urbana, Illinois 61801-3080 (United States))
1994-11-01
A simple and computationally efficient way of finding inverse avalanches for Abelian sandpiles, called the inverse particle addition operator, is presented. In addition, the method is shown to be optimal in the sense that it requires the minimum amount of computation among methods of the same kind. The method is also conceptually succinct because avalanche and inverse avalanche are placed in the same footing.
7, 1043910465, 2007 Mesoscale inversion
Boyer, Edmond
ACPD 7, 1043910465, 2007 Mesoscale inversion T. Lauvaux et al. Title Page Abstract Introduction Discussions Mesoscale inversion: first results from the CERES campaign with synthetic data T. Lauvaux 1,2 , M.lauvaux@lsce.ipsl.fr) 10439 #12;ACPD 7, 1043910465, 2007 Mesoscale inversion T. Lauvaux et al. Title Page Abstract
Probabilistic Approach to Inverse Problems
Klaus Mosegaard; Albert Tarantola
2002-01-01
In 'inverse problems' data from indirect measurements are used to estimate unknown parameters of physical systems. Uncertain data, (possibly vague) prior information on model parameters, and a physical theory relating the model parameters to the observations are the fundamental elements of any inverse problem. Using concepts from probability theory, a consistent formulation of inverse problems can be made, and, while
Molecular Gas Kinematics in Barred Spiral Galaxies
Michael W. Regan; Kartik Sheth; Stuart N. Vogel
1999-08-10
To quantify the effect that bar driven mass inflow can have on the evolution of a galaxy requires an understanding of the dynamics of the inflowing gas. In this paper we study the kinematics of the dense molecular gas in a set of seven barred spiral galaxies to determine which dynamical effects dominate. The kinematics are derived from observations of the CO J=(1-0) line made with the Berkeley-Illinois-Maryland Association (BIMA) millimeter array. We compare the observed kinematics to those predicted by ideal gas hydrodynamic and ballistic cloud-based models of gas flow in a barred potential. The hydrodynamic model is in good qualitative agreement with both the current observations of the dense gas and previous observations of the kinematics of the ionized gas. The observed kinematics indicate that the gas abruptly changes direction upon entering the dust lanes to flow directly down the dust lanes along the leading edge of the bar until the dust lanes approach the nuclear ring. Near the location where the dust lanes intersect the nuclear ring, we see two velocity components: a low velocity component, corresponding to gas on circular orbits, and a higher velocity component, which can be attributed to the fraction of gas flowing down the bar dust lane which sprays past the contact point toward the other half of the bar. The ballistic cloud-based model of the ISM is not consistent with the observed kinematics. The kinematics in the dust lanes require large velocity gradients which cannot be reproduced by an ISM composed of ballistic clouds with long mean-free-paths. Therefore, even the dense ISM responds to hydrodynamic forces.
Interplanetary stream magnetism - Kinematic effects
NASA Technical Reports Server (NTRS)
Burlaga, L. F.; Barouch, E.
1976-01-01
The particle density and the magnetic-field intensity and direction are calculated for volume elements of the solar wind as a function of the initial magnetic-field direction and the initial speed gradient. It is assumed that the velocity is constant and radial. These assumptions are approximately valid between about 0.1 and 1.0 AU for many streams. Time profiles of the particle density, field intensity, and velocity are calculated for corotating streams, neglecting effects of pressure gradients. The compression and rarefaction of the magnetic field depend sensitively on the initial field direction. By averaging over a typical stream, it is found that the average radial field intensity is inversely proportional to the square of the heliocentric distance, whereas the average intensity in the direction of the planets' motion does not vary in a simple way, consistent with deep space observations. Changes of field direction may be very large, depending on the initial angle; but when the initial angle at 0.1 AU is such that the base of the field line corotates with the sun, the spiral angle is the preferred direction at 1 AU. The theory is also applicable to nonstationary flows.
Kinematic reconstruction of the Caribbean region since the Early Jurassic
NASA Astrophysics Data System (ADS)
Boschman, L. M.; Van Hinsbergen, D. J.
2013-12-01
The Caribbean region has a complex tectonic history that resulted from the interplay of the North and South American, the Caribbean, and (Paleo-)Pacific plates. Being largely surrounded by long-lived subduction zones and transform boundaries, reconstructing Caribbean plate motion into the global plate circuit cannot be done using marine magnetic anomalies. Here, we present a fully quantitative, kinematically consistent tectonic reconstruction, back to 200 Ma, using the Atlantic plate circuit as boundary condition. This reconstruction is made in GPlates freeware and all reconstruction files are made available. To restore Caribbean plate motion between the American continents, we use a reconstruction hierarchy based on strike-slip and thrust belt records, using regionally extensive geological phenomena such as the Great Arc of the Caribbean, the Caribbean Large Igneous Province (CLIP) and the Caribeana high-pressure belt as correlation markers. The resulting model restores the Caribbean plate back along the Cayman Trough and strike-slip faults in Guatemala, offshore Nicaragua, offshore Belize and along the Northern Andes towards its position of origin, west of the North and South American continents. Two plate kinematic scenarios for the origin of the Caribbean plate lithosphere are evaluated; an origin from Proto-Caribbean/Atlantic spreading, or from spreading within the Panthalassa domain: we conclude that the latter can provide a simpler explanation. Placing our reconstruction in the most recent mantle reference frames shows that the CLIP erupted 2-3000 km east of, and is probably not the result of the plume head stage of the Galápagos hotspot. Finally, our reconstruction suggests that all modern subduction zones surrounding the Caribbean plate probably formed by inversion of transform faults, two of these (along the southern Mexican and NW South American margins) strongly diachronously as a result of migrating trench-trench-transform triple junctions.
NSDL National Science Digital Library
The Exploratorium
2012-07-11
In this math activity related to light, learners explore why a light, such as a candle or a streetlight, looks dimmer the farther away from it we get. The answer lies in the Inverse Square Law, which learners demonstrate using graph paper or perfboard. (Two methods are given for this activity.) Learners will discover that the intensity of light is described by the power distributed over an area.
Axel Dürrbaum; Willy Klier; Hubert Hahn
2002-01-01
The objective of this paper is to check the efficiency and validity oftwo approaches for computing derivatives of complex functions,automatic differentiation using ADOLC and symbolicdifferentiation using MACSYMA. This has been done in three benchmarkexamples, where the gradient of a Helmholtz energy function has beencomputed for different dimensions of independent variables (Example 1)and Jacobian matrices of inverse kinematics of planar and
Optimal pumping kinematics of a cilium
NASA Astrophysics Data System (ADS)
Eloy, Christophe; Lauga, Eric
2012-11-01
In a variety of biological processes, eukaryotic cells use cilia to transport flow. Although the internal molecular structure of cilia has been remarkably conserved throughout evolution, experimental observations report qualitatively diverse kinematics in different species. To address this diversity, we have determined numerically the kinematics of the most efficient cilium. Specifically, we have computed the time-periodic deformation of a wall-bound elastic filament leading to transport of a surrounding fluid at minimum energetic cost. Here, the energetic cost is taken to be the sum of positive works done by the internal torques, such that elastic energy is not conservative. The optimal kinematics are found to strongly depend on the cilium bending rigidity through a single dimensionless number, the Sperm number Sp, and closely resemble the two-stroke ciliary beating pattern observed experimentally. We acknowledge supports from the EU (fellowship PIOF-GA-2009-252542 to C.E.) and the NSF (grant CBET-0746285 to E.L.).
Kinematics of Diffuse Ionized Gas Halos
NASA Astrophysics Data System (ADS)
Rand, R. J.
2005-06-01
Existing long-slit spectral data for edge-on spiral galaxies suggesting that their Diffuse Ionized Gas (DIG) halos rotate slower than their underlying disks are summarized. An attempt to characterize lagging halos using a model of purely ballistic disk-halo flow is discussed, with the result that the model fails badly for the lagging halo of NGC 891, but is somewhat more successful for NGC 5775. New two-dimensional kinematic data on the DIG halo of NGC 4302 are presented, along with a preliminary analysis of its rotation. Two-dimensional data on NGC 5775 and a preliminary analysis of its halo rotation is discussed by Heald et al. (this volume). The halo of NGC 4302 shows clear signs of lagging on its approaching side, but also strong indications of peculiar kinematics. The kinematics of the receding side are more complex.
Kinematics of Diffuse Ionized Gas Halos
R. J. Rand
2004-09-22
Existing long-slit spectral data for edge-on spiral galaxies suggesting that their Diffuse Ionized Gas (DIG) halos rotate slower than their underlying disks are summarized. An attempt to characterize lagging halos using a model of purely ballistic disk-halo flow is discussed, with the result that the model fails badly for the lagging halo of NGC 891, but is somewhat more successful for NGC 5775. New two-dimensional kinematic data on the DIG halo of NGC 4302 are presented, along with a preliminary analysis of its rotation. Two-dimensional data on NGC 5775 and a preliminary analysis of its halo rotation is discussed by Heald et al. (this volume). The halo of NGC 4302 shows clear signs of lagging on its approaching side, but also strong indications of peculiar kinematics. The kinematics of the receding side are more complex.
Dark energy as a kinematic effect
Jennen, H
2015-01-01
We present a generalization of teleparallel gravity that is consistent with local spacetime kinematics regulated by the de Sitter group $SO(1,4)$. The mathematical structure of teleparallel gravity is shown to be given by a nonlinear Riemann--Cartan geometry without curvature, which inspires us to build the generalization on top of a de Sitter--Cartan geometry with a cosmological function. The cosmological function is given its own dynamics and naturally emerges nonminimally coupled to the gravitational field in a manner akin to teleparallel dark energy models or scalar-tensor theories in general relativity. New in the theory here presented, the cosmological function gives rise to a kinematic contribution in the deviation equation for the world lines of adjacent free-falling particles. While having its own dynamics, dark energy manifests itself in the local kinematics of spacetime.
SMACK - SMOOTHING FOR AIRCRAFT KINEMATICS
NASA Technical Reports Server (NTRS)
Bach, R.
1994-01-01
The computer program SMACK (SMoothing for AirCraft Kinematics) is designed to provide flightpath reconstruction of aircraft forces and motions from measurements that are noisy or incomplete. Additionally, SMACK provides a check on instrument accuracy and data consistency. The program can be used to analyze data from flight-test experiments prior to their use in performance, stability and control, or aerodynamic modeling calculations. It can also be used in the analysis of aircraft accidents, where the actual forces and motions may have to be determined from a very limited data set. Application of a state-estimation method for flightpath reconstruction is possible because aircraft forces and motions are related by well-known equations of motion. The task of postflight state estimation is known as a nonlinear, fixed-interval smoothing problem. SMACK utilizes a backward-filter, forward-smoother algorithm to solve the problem. The equations of motion are used to produce estimates that are compared with their corresponding measurement time histories. The procedure is iterative, providing improved state estimates until a minimum squared-error measure is achieved. In the SMACK program, the state and measurement models together represent a finite-difference approximation for the six-degree-of-freedom dynamics of a rigid body. The models are used to generate time histories which are likely to be found in a flight-test measurement set. These include onboard variables such as Euler angles, angular rates, and linear accelerations as well as tracking variables such as slant range, bearing, and elevation. Any bias or scale-factor errors associated with the state or measurement models are appended to the state vector and treated as constant but unknown parameters. The SMACK documentation covers the derivation of the solution algorithm, describes the state and measurement models, and presents several application examples that should help the analyst recognize the potential advantages of using state estimation. Complete instructions are given for preparing a coding list for problem solution by SMACK. The use of SMACK as part of an overall flight-test methodology is illustrated, as well as its application for analysis of a windshear accident. The details required for installing the program are presented, including sample output listings to facilitate testing. SMACK is written in FORTRAN 77 for DEC VAX series computers running VMS. Two versions of the source code are provided, a single precision version, which can be ported to Cray series computers, and a VAX double precision version. SMACK can call routines from the commercial package IMSL, or replacement routines which are provided can be used. SMACK solution variables to be plotted are written to an ASCII plot file. A sample plotting program, which is designed to be used with the DISSPLA graphics package, is included; however this program can easily be modified for use with other xy plotting packages. The double precision version requires 10Mb of RAM for execution under VMS. SMACK is available in DEC VAX BACKUP format on a 9-track 1600 BPI magnetic tape (standard distribution) or on a TK50 tape cartridge. This program was developed in 1991. DEC, VAX, and VMS are trademarks of Digital Equipment Corporation. DISSPLA is a trademark of Computer Associates, Inc. IMSL is a registered trademark of IMSL, Inc.
Kinematically versus mechanically aligned total knee arthroplasty.
Dossett, H Gene; Swartz, George J; Estrada, Nicolette A; LeFevre, George W; Kwasman, Bertram G
2012-02-01
The purpose of this study was to compare 2 alignment methods for total knee arthroplasty (TKA): kinematic alignment with the use of patient-specific guides and mechanical alignment with conventional instruments. A randomized, controlled trial of 41 kinematically aligned and 41 mechanically aligned patients was conducted with the patient, radiographic evaluator, and clinical evaluator blinded to the alignment technique. Radiographic measurements were made from long-leg computer tomography scanograms. Clinical outcome scores and motion were measured preoperatively and 6 months postoperatively. The hip-knee-ankle angle (0.3° difference; P=.693) and anatomic angle of the knee (0.8° difference; P=.131) were similar for both groups. In the kinematically aligned group, the angle of the femoral component was 2.4° more valgus (P<.000) and the angle of the tibial component was 2.3° more varus (P<.000) than the mechanically aligned group. At 6 months postoperatively, the Western Ontario and McMaster Universities Osteoarthritis Index score was 16 points better (P<.000), Oxford Score was 7 points better (P=.001), combined Knee Society Score was 25 points better (P=.001), and flexion was 5.0° greater (P=.043) in the kinematically aligned group than in the mechanically aligned group.Our findings suggest that the risk of early failure related to limb or knee alignment should be similar in kinematic and mechanically aligned TKA. More anatomic alignment of the implant was associated with better flexion and better clinical outcome scores in the kinematically aligned group. PMID:22310400
Local Helioseismology as an Inverse Source-Inverse Scattering Problem
NASA Astrophysics Data System (ADS)
Skartlien, R.
2002-02-01
The inverse source and inverse scattering problems for a general inhomogeneous medium is investigated within the framework of helioseismic holography. Holographic images, defined by the method of Lindsey and Braun, or via the Porter-Bojarski equation, define a Fredholm integral equation of the first kind in terms of acoustic sources, scatterers, and absorbers. This integral equation is well posed in the sense that it can be inverted by standard constrained inversion methods. The inversion produces an image that does not distinguish between sources, scatterers, and absorbers. The inversion is necessarily approximate because of the null space of the kernel that defines the Fredholm equation. Physically, the null space corresponds to the nonradiating source contribution, as previously shown by Devaney and Porter. Numerical experiments based on a solar model show that the sidelobes in the ``imaging point-spread function'' are greatly reduced after inversion, such that the image is sharper than the corresponding holographic image.
Knupp, P.M.
1999-01-18
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.
Calibration of parallel kinematic devices using sequential determination of kinematic parameters
JOKIEL JR.,BERNHARD; BIEG,LOTHAR F.; ZIEGERT,JOHN C.
2000-04-06
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.
Sklenar, Heinz; Wüstner, Daniel; Rohs, Remo
2006-02-01
This article describes a method for solving the geometric closure problem for simplified models of nucleic acid structures by using the constant bond lengths approximation. The resulting chain breakage/closure equations, formulated in the space of variable torsion and bond angles, are easy to solve, and have only two solutions. The analytical simplicity is in contrast with the high complexity of the closure problem in the torsion angle space with at most 16 solutions, which has been dealt with by several authors and was solved analytically by Wu and Deem (J. Chem. Phys. 1999, 111, 6625). The discussion on the choice of variables and associated Jacobians is focussed on the question of how conformational equilibration is affected in Monte Carlo simulations of molecular systems. In addition to the closure of the phosphate backbone, it is necessary to also solve the closure problem for the five-membered flexible furanose sugar ring. Explicit closure equations and the resulting Jacobians are given both for the complete four-variable model of the furanose ring and simulations in the phase-amplitude space of the five-membered ring, which are based on the approximate two-variable model of furanose introduced by Gabb et al. (J. Comput. Chem. 1995, 16, 667). The suggested closure algorithm can be combined with collective variables defined by translations and rotations of the monomeric nucleotide units. In comparison with simple internal coordinate moves, the resulting concerted moves describe local structural changes that have high acceptance rates and enable fast conformational equilibration. Appropriate molecular models are put forward for prospective Monte Carlo simulations of nucleic acids, but can be easily adapted to other biomolecular systems, such as proteins and lipid structures in biological membranes. PMID:16355439
Structural fabric of the Palisades Monocline: a study of positive inversion, Grand Canyon, Arizona
Orofino, James Cory
2005-08-29
Cory Orofino, B.A., The Colorado College Chair of Advisory Committee: Dr. Judith S. Chester A field study of positive inversion is conducted to describe associated structural fabrics and to infer kinematic development of the Palisades... of the people who helped. I cannot mention all to whom I am indebted, as it starts with my parents and moves to my many friends, colleagues, teachers, coaches, and professors that I have known from Oak Hall School, The Colorado College, and finally Texas A...
A model of plate kinematics in Gondwana breakup
NASA Astrophysics Data System (ADS)
Eagles, Graeme; König, Matthias
2008-05-01
An accurate model of relative plate motions in Gondwana breakup is based on visual fitting of seafloor isochrons and fracture zones (FZ) from the Riiser-Larsen Sea and Mozambique Basin. Used predictively, the model precisely locates kinematic markers in the West Somali Basin, which allows the conclusion that the spreading centres in the West Somali and Mozambique basins and the Riiser-Larsen Sea formed parts of the boundary between the same two plates. The locations of FZ and less well-defined isochrons from neighbouring regions are also consistent with their formation on other lengths of this same boundary and with its relocation from the West Somali Basin and northern Natal Valley to the West Enderby Basin and Lazarev Sea during chron M10n. Small independently moving plates thus played no role in the breakup of this core part of Gondwana. In an inversion procedure, the data from these areas yield more precise finite rotations that describe the history of the two plates' separation. Breakup is most simply interpreted to have occurred in coincidence with Karoo volcanism, and a reconstruction based on the rotations shows the Lebombo and Mateke-Sabi monoclines and the Mozambique and Astrid ridges as two sets of conjugate volcanic margins. Madagascar's pre-drift position can be used as a constraint to reassess the positions of India and Sri Lanka in the supercontinent.
Doppler Boosting, Superluminal Motion, and the Kinematics of AGN Jets
K. I. Kellermann; Y. Y. Kovalev; M. L. Lister; D. C. Homan; M. Kadler; M. H. Cohen; E. Ros; J. A. Zensus; R. C. Vermeulen; M. F. Aller; H. D. Aller
2007-08-23
We discuss results from a decade long program to study the fine-scale structure and the kinematics of relativistic AGN jets with the aim of better understanding the acceleration and collimation of the relativistic plasma forming AGN jets. From the observed distribution of brightness temperature, apparent velocity, flux density, time variability, and apparent luminosity, the intrinsic properties of the jets including Lorentz factor, luminosity, orientation, and brightness temperature are discussed. Special attention is given to the jet in M87, which has been studied over a wide range of wavelengths and which, due to its proximity, is observed with excellent spatial resolution. Most radio jets appear quite linear, but we also observe curved non-linear jets and non-radial motions. Sometimes, different features in a given jet appear to follow the same curved path but there is evidence for ballistic trajectories as well. The data are best fit with a distribution of Lorentz factors extending up to gamma ~30 and intrinsic luminosity up to ~10^26 W/Hz. In general, gamma-ray quasars may have somewhat larger Lorentz factors than non gamma-ray quasars. Initially the observed brightness temperature near the base of the jet extend up to ~5x10^13 K which is well in excess of the inverse Compton limit and corresponds to a large excess of particle energy over magnetic energy. However, more typically, the observed brightness temperatures are ~2x10^11 K, i.e., closer to equipartition.
Kinematics of the ankle joint complex in snowboarding.
Delorme, Sebastien; Tavoularis, Stavros; Lamontagne, Mario
2005-11-01
Because snowboarders are known to injure their ankles more often than Alpine skiers, it has been postulated that stiffer snowboard boots would provide better protection to the ankle than current soft boots do. Snowboarders are also known to injure their front ankle more often than their back ankle, presumably because of the asymmetrical rotations of the ankles due to asymmetrical binding adjustement. To test these hypotheses, we measured the kinematics of the feet and legs of 5 snowboarders wearing soft boots and stiffer step-in boots during snowboarding maneuvers using an electromagnetic motion tracking system. The results were expressed in anatomically relevant rotations of the ankle joint complex, namely dorsi-/plantar flexion, eversion/inversion, and internal/external rotation. The measured ankle rotations show differences in the movement patterns of the front and back legs. Step-in boots were shown to allow less dorsiflexion, eversion, and external rotation than softer boots, possibly explaining why they are associated with a lower rate of fractures of the talus than soft boots. PMID:16498184
The kinematics of the Virgo cluster revisited
B. Binggeli; C. C. Popescu; G. A. Tammann
1993-01-01
The paper updates the velocity data of Virgo cluster galaxies and reconsiders the kinematic structure of the Virgo cluster. New velocities are given for 144 galaxies listed in the Virgo Cluster Catalog (VCC). Improved velocities are given for another 131 VCC galaxies. The Virgo cluster is disentangled from its surrounding clouds of galaxies, and the likely members of each of
A geodynamic framework for eastern Mediterranean kinematics
Paul Lundgren; Domenico Giardini; Raymond M. Russo
1998-01-01
We use a finite element model incorporating plate motion boundary conditions, fault constraints, and space geodetic velocities to calculate eastern Mediterranean plate kinematics and to estimate the motion of the region's major faults. We then use subsets of these constraints to generate models testing different scenarios of driving forces (slab roll-back at the Hellenic arc, Arabian plate push, gravitational collapse
Kinematic-Wave Furrow Irrigation Model
Wynn R. Walker; Allan S. Humpherys
1983-01-01
A kinematic-wave model of furrow irrigation under both continu- ous and surged flow management was developed and verified. Numerical so- lution of the differential continuity equation is accomplished with a Eulerian first-order integration coupled with the assumption that flow rate and flow area are uniquely related by the Manning uniform flow equation. Field data from three Colorado sites, a Utah
Kinematical test of the ICRS inertiality
NASA Astrophysics Data System (ADS)
Bobylev, V. V.
2004-09-01
The kinematics of the Hipparcos (ESA, 1997) and TRC (Hoeg et al. 1998) stars has been tested using Ogorodnikov-Milne model (Ogorodnikov, 1965, Clube, 1972). On the basis of the TRC the Oort constants were determined. With the use of this approach the corrections of the luni-solar precession constant IAU (1976) have been derived.
Is precession electron diffraction kinematical? Part I
T. A. White; A. S. Eggeman; P. A. Midgley
2010-01-01
Results from multislice simulations are presented which demonstrate that diffracted intensities obtained using precession electron diffraction are less sensitive to the phases of structure factors compared to electron diffraction intensities recorded without precession. Since kinematical diffraction intensities depend only on the moduli of the structure factors, this result supports previous research indicating that the application of precession leads to electron
Singularity-theoretic methods in robot kinematics
Donelan, Peter
theory provides methodologies for a deeper analysis with the aim of classifying singularities, providing-theoretic methods in robot kinematics and presents some new results. Keywords: Singularity theory; Robot manipulator; Transversality; Lie group; Genericity; Screw systems. #12;1 Introduction In simple terms, a singularity
On the Kinematic Analysis of Robotic Mechanisms
James Nielsen; Bernard Roth
1999-01-01
The kinematic analyses, of manipulators and other robotic devices composed of mechanical links, usually depend on the solution of sets of nonlinear equations. There are a variety of both numerical and algebraic techniques available to solve such systems of equations and to give bounds on the number of solutions. These solution methods have also led to an understanding of how
KINEMATIC DISTANCE ASSIGNMENTS WITH H I ABSORPTION
Jones, Courtney; Dickey, John M. [School of Mathematics and Physics, Private Bag 37, University of Tasmania, Hobart 7000 (Australia)
2012-07-01
Using H I absorption spectra from the International Galactic Plane Survey, a new method is implemented to resolve the kinematic distance ambiguity for 75 H II regions with known systemic velocities from radio recombination lines. A further 40 kinematic distance determinations are made for H II region candidates without known systemic velocities through an investigation of the presence of H I absorption around the terminal velocity. New kinematic distance determinations can be used to further constrain spiral arm parameters and the location and extent of other structures in the Milky Way disk. H I absorption toward continuum sources beyond the solar circle is also investigated. Follow-up studies of H I at higher resolution than the 1' to 2' of existing Galactic Plane Surveys will provide kinematic distances to many more H II regions on the far side of the Galactic center. On the basis of the velocity channel summation technique developed in this paper, a much larger sample of H II regions will be analyzed in a future paper to remove the near-far distance ambiguity.
Technical Note Pulmonary Kinematics From Tagged Hyperpolarized
Utah, University of
the feasibility of a novel method for quantifying 3D regional pulmonary kinematics from hyperpolarized helium-3 tagged MRI in human sub- jects using a tailored image processing pipeline and a recently developed of disease and the predicted extent of recovery in the afflicted lung. Recent developments in lung MRI using
Spitzer SAGE Followup: Kinematics of the LMC
Knut Olsen; Robert Blum; Karl Gordon; Jason Harris; Margaret Meixner; Sally Oey; Schuyler van Dyk; Dennis Zaritsky
2007-01-01
We propose to use the CTIO 4-m telescope and Hydra spectrograph to measure velocites for ~4500 LMC carbon stars and red supergiants (RSGs). Our pointings uniformly sample the entire H I disk of the LMC, covering significant area untouched by previous velocity surveys. These data will allow us to investigate a number of important issues concerning the LMC's kinematics. First,
Lower extremity kinematics of athletics curve sprinting.
Alt, Tobias; Heinrich, Kai; Funken, Johannes; Potthast, Wolfgang
2015-01-01
Curve running requires the generation of centripetal force altering the movement pattern in comparison to the straight path run. The question arises which kinematic modulations emerge while bend sprinting at high velocities. It has been suggested that during curve sprints the legs fulfil different functions. A three-dimensional motion analysis (16 high-speed cameras) was conducted to compare the segmental kinematics of the lower extremity during the stance phases of linear and curve sprints (radius: 36.5 m) of six sprinters of national competitive level. Peak joint angles substantially differed in the frontal and transversal plane whereas sagittal plane kinematics remained unchanged. During the prolonged left stance phase (left: 107.5 ms, right: 95.7 ms, straight: 104.4 ms) the maximum values of ankle eversion (left: 12.7°, right: 2.6°, straight: 6.6°), hip adduction (left: 13.8°, right: 5.5°, straight: 8.8°) and hip external rotation (left: 21.6°, right: 12.9°, straight: 16.7°) were significantly higher. The inside leg seemed to stabilise the movement in the frontal plane (eversion-adduction strategy) whereas the outside leg provided and controlled the motion in the horizontal plane (rotation strategy). These results extend the principal understanding of the effects of curve sprinting on lower extremity kinematics. This helps to increase the understanding of nonlinear human bipedal locomotion, which in turn might lead to improvements in athletic performance and injury prevention. PMID:25495196
Prof. Alessandro De Luca Kinematic calibration
De Luca, Alessandro
! an " # $ $$ % & ' '' ! d = d1 ! dn " # $ $ $ % & ' ' ' " = "1 ! "n # $ % %% & ' ( ((! are typically measured by encoders not be consistent with the "zero reference" of the robot direct kinematics (joint angle measures are constantly set of D-H parameters, based on independent external (accurate!) measurements ! experiments to be done
Stellar Archeology : Chemical Compositions and Kinematics
NASA Astrophysics Data System (ADS)
Stringer, Bayard; Carney, Bruce
2011-10-01
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.
Kinematic analysis of reaching in the cat
J. H. Martin; S. E. Cooper; C. Ghez
1995-01-01
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
Chemical tagging of stellar kinematic groups
NASA Astrophysics Data System (ADS)
Tabernero, H. M.; Montes, D.; González Hernández, J. I.
2013-05-01
Stellar Kinematic Groups are kinematical coherent groups of stars which might share a common origin. These groups spread through the Galaxy over time due to tidal effects caused by galactic rotation and disc heating, however the chemical information survives. The aim of chemical tagging is to show that abundances of every chemical element must be homogeneus among candidate members. We have studied the case of the Hyades Supercluster and the Ursa Major Moving Group for kinematically selected FGK stars, based on high-resolution spectroscopic observations obtained at the 1.2 m Mercator Telescope with the HERMES Spectrograph. Stellar atmospheric parameters (T_{eff}, log{g}, ? and [Fe/H]) have been determined using an own-implemented automatic code (StePar) which makes use of the sensibility from iron EWs measured in the spectra. We have derived the chemical abundances of several elements and their [X/Fe] ratios. Thus, we finally perform a careful differential abundance analysis using a known member of each cluster as a reference star, with the aim to clarify the origin of these kinematical groups.
ANALYTIC MODELING OF THE MORETON WAVE KINEMATICS
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
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.
KINEMATIC ANALYSIS OF LOWER MOBILITY COOPERATIVE ARMS BY SCREW THEORY
Paris-Sud XI, Université de
KINEMATIC ANALYSIS OF LOWER MOBILITY COOPERATIVE ARMS BY SCREW THEORY Philip Long1 , St´ephane Caro.secondname}@irccyn.ec-nantes.fr Keywords: Cooperative Manipulators:Humanoid Robots: Screw theory Abstract: This paper studies the kinematic
Kinematic conditioning augmentation to haptic interface for teleoperation
Dongaonkar, Ranjeet Manohar
2003-01-01
A solution is proposed for the kinematic conditioning problem in teleoperation. The proposed solution helps the operator in understanding the kinematic conditioning of the slave manipulator with the help of haptic interface. Teleoperation involves...
Detailed stellar and gaseous kinematics of M31
NASA Astrophysics Data System (ADS)
Opitsch, Michael; Fabricius, Maximilian; Saglia, Roberto; Bender, Ralf; Williams, Michael
2015-02-01
We have collected optical integral field spectroscopic data for M31 with the spectrograph VIRUS-W that result in kinematic maps of unprecedented detail. These reveal the presence of two kinematically distinct gas components.
NASA Astrophysics Data System (ADS)
Deverchere, J.; Yelles, K.; Bracene, R.; Mercier de Lepinay, B. F.; Cattaneo, A.; Medaouri, M.; Gaullier, V.; Babonneau, N.; Ratzov, G.; Boudiaf, A.; Graindorge, D.; Kherroubi, A.; Strzerzynski, P. H.; Authemayou, C.; Djellit, H.; Heddar, A.; Maradja'03; Maradja-Samra'05 Scientific Teams
2011-12-01
The reasons to study the Algerian margin (Western Mediterranean) are at least threefold: (1) the seismic hazard offshore is obviously present but unconstrained, (2) the way the opening of the Algerian basin occurred is highly debated, and (3) this margin represents one of the rare examples on Earth of an ongoing subduction inception. We present an overview of recent findings on the tectonic evolution of this margin, where most of the plate convergence between Africa and Europe is taken up today, mostly from cruises MARADJA and MARADJA2/SAMRA led by joint Algerian and French teams. Large, overlapping active thrust faults and folds apparently dominate the seismotectonic pattern from the Atlas domain on land to the foot of the margin offshore, with a clear segmentation. Strain is distributed across the whole area, with a significant part of the relative plate convergence taken up offshore. Fault activity offshore is tenuous and most often indirect (Plio-Quaternary growth strata, folds, uplifted basins, scars and slope breaks). Along the eastern margin, faults form stepwise, en-échelon systems on the slope and in the deep basin. Some thrusts identified turn to fault-propagation folds at the sub-surface. Thrusts interact with the sediment flux, Messinian salt and seafloor currents, forming complex structures at deep-sea fans and scarps or scars on the main slope breaks. The 2003 Mw 6.9 Boumerdes rupture is correlated segmented cumulative scarps on the slope and at the foot of the margin. Using various VHR seismic reflection and coring analyses, we show that the record of turbidite deposition since ca. 10.000 yrs can be identified and correlated over long distances within or across large segments of the margin affected by the 1954, 1980 and 2003 events. The consequences in term of earthquake size and recovery of their recurrences (identification of paleo-events) are explored and discussed. Although we cannot associate the triggering of large turbidity currents to a given fault, we find that the Algerian margin gathers favourable conditions to reconstruct times series of turbidites associated to significant earthquakes. Finally, we show that the structures inherited from the Algerian basin opening and from the Alpine belt building (AlKaPeCa blocks migration and collision) determine for a large part the size, style and location of this strain pattern. The overall geometry indicates the predominance of back thrusts, implying underthrusting of the young oceanic crust, although large dextral strike-slip structures may guide deformation at some places on land. The recent (probably less than 3 Ma) reactivation of the Algerian margin is strongly influenced by the subduction of the Tethyan Maghrebian ocean, implying not only an important roll-back of the slab, but also strong thermal, magmatic and isostatic effects of the slab evolution at depth.
The Pindos Fold-and-thrust belt (Greece): inversion kinematics of a passive continental margin
Konstantinos Skourlis; Theodor Doutsos
2003-01-01
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
A motion planner for a redundant mobile manipulator using the inverse kinematics
Gupta, Gautam Jagannath
2003-01-01
application in personal robotics as well as a service robot in various fields like factory automation, personal robotics, underwater exploration, surgery, space robotics and nuclear power plant. Furthermore, application of haptics interface for the mobde... to scan natural terrain and detect metal objects hidden beneath. The control of a mo- bile manipulator by a haptic device, via internet or using teleoperation has added a new dimension to the robotics and expanded the domain of application. Elhaji et...
Measurement of 4He(12C,16 O) ? Reaction in Inverse Kinematics
NASA Astrophysics Data System (ADS)
Fujita, K.; Sagara, K.; Teranishi, T.; Iwasaki, M.; Kodama, D.; Liu, S.; Matsuda, S.; Mitsuzumi, T.; Moon, J. Y.; Rosary, M. T.; Yamaguchi, H.
2013-08-01
A cross section measurement employing a direct 16O detection method for the reaction energies from E cm = 2.4 to 0.7 MeV is planned at Kyushu University Tandem Laboratory. To perform this experiment and to obtain quantitative information about the cross section to within an error of 10%, we have developed several instruments, including a blow-in type windowless gas target and a ionization chamber. A target thickness of 24 × 3.9 Torr cm was achieved using the developed gas target. The particle identification was successfully performed by using the energy deposit in the ionization chamber. Experiments were performed at E cm = 2.4 and 1.5 MeV using the developed instruments and the cross sections were obtained.
A biomimetic approach to inverse kinematics for a redundant robot arm
Artemiadis, Panagiotis
Redundant robots have received increased attention during the last decades, since they provide solutions to problems investigated for years in the robotic community, e.g. task-space tracking, obstacle avoidance etc. However, ...
Inverse-kinematics one-neutron pickup with fast rare-isotope beams
Gade, A.; Baugher, T.; Brown, B. A.; Glasmacher, T.; McDaniel, S.; Ratkiewicz, A.; Stroberg, S. R. [National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824 (United States); Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824 (United States); Tostevin, J. A. [Department of Physics, Faculty of Engineering and Physical Sciences, University of Surrey, Guildford, Surrey GU2 7XH (United Kingdom); Department of Physics, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8550 (Japan); Bazin, D.; Campbell, C. M.; Grinyer, G. F.; Weisshaar, D.; Winkler, R. [National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824 (United States); Meierbachtol, K. [National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824 (United States); Department of Chemistry, Michigan State University, East Lansing, Michigan 48824 (United States); Walsh, K. A. [Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824 (United States)
2011-05-15
Measurements and reaction model calculations are reported for single-neutron pickup reactions onto a fast {sup 22}Mg secondary beam at 84 MeV per nucleon. Measurements made on both carbon and beryllium targets, having very different structures, were used to investigate the likely nature of the pickup reaction mechanism. The measurements involve thick reaction targets and {gamma}-ray spectroscopy of the projectile-like reaction residue for final-state resolution, which permit experiments with low incident beam rates compared to traditional low-energy transfer reactions. From measured longitudinal momentum distributions we show that the {sup 12}C({sup 22}Mg,{sup 23}Mg+{gamma})X reaction largely proceeds as a direct two-body reaction, with the neutron transfer producing bound {sup 11}C target residues. The corresponding reaction on the {sup 9}Be target seems to largely leave the {sup 8}Be residual nucleus unbound at excitation energies high in the continuum. We discuss the possible use of such fast-beam one-neutron pickup reactions to track single-particle strength in exotic nuclei and also their expected sensitivity to neutron high-l (intruder) states, which are often direct indicators of shell evolution and the disappearance of magic numbers in the exotic regime.
Block model of western US kinematics from inversion of geodetic, fault slip, and earthquake data
NASA Astrophysics Data System (ADS)
McCaffrey, R.
2003-12-01
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.
L. A. Riley; M. L. Agiorgousis; T. R. Baugher; D. Bazin; M. Bowry; P. D. Cottle; F. G. DeVone; A. Gade; M. T. Glowacki; K. W. Kemper; E. Lunderberg; D. M. McPherson; S. Noji; F. Recchia; B. V. Sadler; M. Scott; D. Weisshaar; R. G. T. Zegers
2014-07-20
We have performed measurements of the $0_\\mathrm{g.s.}^+ \\rightarrow 2_1^+$ excitations in the neutron-rich isotopes $^{48,50}$Ca via inelastic proton scattering on a liquid hydrogen target, using the GRETINA $\\gamma$-ray tracking array. A comparison of the present results with those from previous measurements of the lifetimes of the $2_1^+$ states provides us the ratio of the neutron and proton matrix elements for the $0_\\mathrm{g.s.}^+ \\rightarrow 2_1^+$ transitions. These results allow the determination of the ratio of the proton and neutron effective charges to be used in shell model calculations of neutron-rich isotopes in the vicinity of $^{48}$Ca.
A study of generalized inverses
McKinney, Nancy Lee
1973-01-01
A STUDY OF GENERALIZED INVERSES A Thesis by NANCY LEE MCKINNEY Submitted to the Graduate College of Texas ASM University in partial fulfillment of the requirement for the degree of MASTER OF SCIENCE August 1973 Major Subject: Mathematics A... STUDY OF GENERALIZED INVERSES A Thesis by NANCY LEE MCKINNEY Approved as to style and content by: airman o ittee Hea o epartment e er Me er August 1973 ABSTRACT A Study of Generalized Inverses. (August 1973) Nancy Lee NcKinney, B. A...
Wavelet Sparse Approximate Inverse Preconditioners
NASA Technical Reports Server (NTRS)
Chan, Tony F.; Tang, W.-P.; Wan, W. L.
1996-01-01
There is an increasing interest in using sparse approximate inverses as preconditioners for Krylov subspace iterative methods. Recent studies of Grote and Huckle and Chow and Saad also show that sparse approximate inverse preconditioner can be effective for a variety of matrices, e.g. Harwell-Boeing collections. Nonetheless a drawback is that it requires rapid decay of the inverse entries so that sparse approximate inverse is possible. However, for the class of matrices that, come from elliptic PDE problems, this assumption may not necessarily hold. Our main idea is to look for a basis, other than the standard one, such that a sparse representation of the inverse is feasible. A crucial observation is that the kind of matrices we are interested in typically have a piecewise smooth inverse. We exploit this fact, by applying wavelet techniques to construct a better sparse approximate inverse in the wavelet basis. We shall justify theoretically and numerically that our approach is effective for matrices with smooth inverse. We emphasize that in this paper we have only presented the idea of wavelet approximate inverses and demonstrated its potential but have not yet developed a highly refined and efficient algorithm.
3D kinematics using dual quaternions: theory and applications in neuroscience.
Leclercq, Guillaume; Lefèvre, Philippe; Blohm, Gunnar
2013-01-01
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
Distributed Dynamics of Systems with Closed Kinematic Chains
Krovi, Venkat
Distributed Dynamics of Systems with Closed Kinematic Chains Waseem Ahmad Khan wakhan@cim.mcgill.ca Centre for Intelligent Machines, McGill University Distributed Dynamics of Systems with Closed Kinematic Distributed Dynamics of Systems with Closed Kinematic Chains p.2/45 #12;Introduction Problems associated
Characterization and Comparison of Rover Locomotion Performance Based on Kinematic
Paris-Sud XI, Université de
Characterization and Comparison of Rover Locomotion Performance Based on Kinematic Aspects Thomas.thueer, roland.siegwart}@mavt.ethz.ch Summary. Evaluation and comparison of locomotion performance of rovers. In this work, three different rovers were analyzed from a kinematic point of view. Based on a kinematic model
Advances in Robot Kinematics 13th International Symposium
Nawratil, Georg
Advances in Robot Kinematics 13th International Symposium June 2428, 2012 Innsbruck, Austria ARK for researchers working in robot kinematics and to stimulate new directions of research by forging links between robot kinematics and other areas. Organized by Unit Geometry and CAD, University Inns- bruck, Austria
Upper Limb Assessment in Tetraplegia: Clinical, Functional and Kinematic Correlations
ERIC Educational Resources Information Center
Cacho, Enio Walker Azevedo; de Oliveira, Roberta; Ortolan, Rodrigo L.; Varoto, Renato; Cliquet, Alberto
2011-01-01
The aim of this study was to correlate clinical and functional evaluations with kinematic variables of upper limp reach-to-grasp movement in patients with tetraplegia. Twenty chronic patients were selected to perform reach-to-grasp kinematic assessment using a target placed at a distance equal to the arm's length. Kinematic variables (hand peak…
Inverse problem in optical diffusion tomography. IV. Nonlinear inversion formulas
Vadim A. Markel; Joseph A. O'Sullivan; John C. Schotland
2003-01-01
We continue our study of the inverse scattering problem for diffuse light. In contrast to our earlier work, in which we considered the linear inverse problem, we now consider the nonlinear problem. We obtain a solution to this problem in the form of a functional series expansion. The first term in this expansion is the pseudoinverse of the linearized forward-scattering
Selective inverse lithography methodology
NASA Astrophysics Data System (ADS)
Lim, ChinTeong; Temchenko, Vlad; Niehoff, Martin
2010-04-01
Selective Inverse Lithography (ILT) approach recently introduced by authors [1] has proven to be advantageous for extending life-span of lower-NA 193nm exposure tools to achieve satisfactory 65nm contact layer patterning. We intend to find an alternative solution without the need for higher NA tools and advanced light source optimization. In this paper we explore possible region selection criteria for ILT application based on pitch for a full chip optical proximity correction (OPC). Through studying the impact of a given selection criteria on runtime, resolution, and the process window we recommend an optimal combination. With a justified choice of an ILT selection criteria, we construct a hybrid OPC flow comprising a recursive sequence of direct assist features generation, selective ILT application, layout repair, model OPC and hot spots screening.
Inverse magnetorheological fluids.
Rodríguez-Arco, L; López-López, M T; Zubarev, A Y; Gdula, K; Durán, J D G
2014-09-01
We report a new kind of field-responsive fluid consisting of suspensions of diamagnetic (DM) and ferromagnetic (FM) microparticles in ferrofluids. We designate them as inverse magnetorheological (IMR) fluids for analogy with inverse ferrofluids (IFFs). Observations on the particle self-assembly in IMR fluids upon magnetic field application showed that DM and FM microparticles were assembled into alternating chains oriented along the field direction. We explain such assembly on the basis of the dipolar interaction energy between particles. We also present results on the rheological properties of IMR fluids and, for comparison, those of IFFs and bidispersed magnetorheological (MR) fluids. Interestingly, we found that upon magnetic field application, the rheological properties of IMR fluids were enhanced with respect to bidispersed MR fluids with the same FM particle concentration, by an amount greater than the sum of the isolated contribution of DM particles. Furthermore, the field-induced yield stress was moderately increased when up to 30% of the total FM particle content was replaced with DM particles. Beyond this point, the dependence of the yield stress on the DM content was non-monotonic, as expected for FM concentrations decreasing to zero. We explain these synergistic results by two separate phenomena: the formation of exclusion areas for FM particles due to the perturbation of the magnetic field by DM particles and the dipole-dipole interaction between DM and FM particles, which enhances the field-induced structures. Based on the second phenomenon, we present a theoretical model for the yield stress that semi-quantitatively predicts the experimental results. PMID:25022363
Inverse Spectral Problem Proof of Main Result
Stanhope, Liz
Inverse Spectral Problem Proof of Main Result Geodesics on Weighted Projective Spaces Zuoqin Wang of Main Result Inverse Spectral Geometry Main Result Inverse Spectral Geometry Manifold setting: (M, g Proof of Main Result Inverse Spectral Geometry Main Result Inverse Spectral Geometry Manifold setting
Abel inversion by Kalman filtering
E. Hansen; Phaih-Lan Law
1984-01-01
The Abel transform and its inverse appear in a wide variety of problems, where it is necessary to reconstruct an axisymmetric function from its line-integral projections. This paper is concerned with Abel inversion from noisy experimental data, and presents a recursive approach based on a state space model of the forward transform and a Kalman filter.
Inverse Problems and Industrial Mathematics
Fulmek, Markus
line coke ore charging of ore and coke layers indirect reduction of ore by CO and H2 Inverse Problems in process parameters - charging strategy (distribution of coke-ore layers) - different raw materials Inverse and uniform quality of produced liquid iron - the decrease of coke consumption - a uniform gas mass flow
Industrial Mathematics and Inverse Problems
Fulmek, Markus
#12;The Industrial Mathematics Structure in Linz 5 #12;The Blast Furnace Process 6 #12;Aims and thermal wear, the wall at the hearth is (slowly) washed out danger of breakthrough. Question: Can one infer the thickness of the wall from thermal measurements outside? Inverse problem; other inverse
Trans-dimensional geoacoustic inversion.
Dettmer, Jan; Dosso, Stan E; Holland, Charles W
2010-12-01
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
NASA Astrophysics Data System (ADS)
Sirovich, Livio; Pettenati, Franco; Cavallini, Fabio
2013-12-01
inverted the regional pattern of intensities of the catastrophic earthquake of 1694 in the southern Apennines and determined the geometrical and kinematic characteristics of its source, including the double-couple orientation (strike angle 299° ± 10°, dip 54° ± 12°, and rake 309° ± 11°; pure dip-slip solution not precluded). The objective nonlinear inversion was performed using the simple 11 parameter kinematic-function model (KF) with a niching genetic algorithm technique. The similarity between the pattern of the field intensities of the 1694 earthquake and the synthetic pattern is striking. This result is supported by the fact that our inversion technique was verified in the study area, where it was able to again find the source of the Ms 6.9 Irpinia 1980 earthquake, known from instruments and from field surveys of the rupture. This type of inversion enables researchers to exploit the extensive intensity data from Italy and other countries to extend the knowledge of seismotectonic activity to preinstrumental times. New paleoseismological evidence and even published descriptions of the fault rupture by witnesses of the 1694 earthquake were found, confirming our results. We also present and apply a new algorithm, of general interest, to calculate disorientations between double-couples via standard linear algebra. The 3-D rotations that bring the pairwise orthogonal unit vectors that were estimated by our intensity inversion into the instrumental triples of the 1980 Irpinia earthquake, assumed as benchmarks, provide verification of our algorithm.
NASA Astrophysics Data System (ADS)
Sirovich, Livio; Pettenati, Franco
2004-10-01
We demonstrate that it is possible to retrieve geometric and kinematic information about the source of a destructive past earthquake by inverting its regional macroseismic intensity patterns. In fact, in the case study the inversion results agree with the seismological instrumental measurements of the 1930s and with neotectonic evidence. This leads to the hope that more knowledge about preinstrumental events can be obtained: a key toward improving the calculation of seismic hazard, mostly in the Old World. After validating our technique on the 1987 Whittier Narrows, California, earthquake [, 2003; , 2004] we achieve the present results by investigating an earthquake that happened in 1936 in northeast Italy. The automatic inversions were performed by using a simplified formula for body waves that radiate from a linear source. The inversion shows two minima on the hypersurface of the minimum residuals (calculated - observed intensity at all sites) in the multiparameter model space. These two minimum variance source models resemble the two auxiliary planes of the same theoretical fault plane solution, similar to that given by the standard use of the first P wave arrivals. The present result encourages us to treat more cases and to explore new inversion techniques for quantitatively treating the intensity patterns of earthquakes because, at least in some cases, they carry geometric and kinematic information about their source.
Galactic warp kinematics: model vs. observations
NASA Astrophysics Data System (ADS)
Abedi, H.; Figueras, F.; Aguilar, L.; Mateu, C.; Romero-Gómez, M.; López-Corredoira, M.; Garzón, F.
2015-05-01
We test the capability of several methods to identify and characterise the warping of the stellar disc of our Galaxy in the Gaia era. We have developed a first kinematic model for the galactic warp and derived the analytical expressions for the force field of a warped Miyamoto- Nagai potential. We have generated realistic mock catalogues of OB, A and red clump stars within the warped galactic disc, where a very complete model of Gaia observables and their expected errors are included. We use the family of Great Circle Cell Counts (GC3) methods and LonKin methods for detecting and characterising the galactic warp. As a complementary work, we look into one of the existing proper motion catalogue namely the UCAC4, and look for the kinematic signature of the warp. We demonstrate the necessity of correcting for a possible residual rotation of the Hipparcos celestial reference frame with respect to the extra galactic inertial one.
On kinematical constraints in Regge calculus
V. Khatsymovsky
1993-11-04
In the (3+1)D Hamiltonian Regge calculus (one of the coordinates, $ t$, is continuous) conjugate variables are (defined on triangles of discrete 3D section $ t=const$) finite connections and antisymmetric area bivectors. The latter, however, are not independent, since triangles may have common edges. This circumstance can be taken into account with the help of the set of kinematical (that is, required to hold by definition of Regge manifold) bilinear constraints on bivectors. Some of these contain derivatives over $ t$, and taking them into account with the help of Lagrange multipliers would result in the new dynamical variables not having analogs in the continuum theory. It is shown that kinematical constraints with derivatives are consequences of eqs. of motion for Regge action supplemented with the rest of these constraints without derivatives and can be omitted; so the new dynamical variables do not appear.
A kinematic method to probe cosmic acceleration
NASA Astrophysics Data System (ADS)
Barboza, Edésio M.; Carvalho, F. C.
2012-08-01
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.
Philippine fault: A key for Philippine kinematics
NASA Astrophysics Data System (ADS)
Barrier, E.; Huchon, P.; Aurelio, M.
1991-01-01
On the basis of new geologic data and a kinematic analysis, we establish a simple kinematic model in which the motion between the Philippine Sea plate and Eurasia is distributed on two boundaries: the Philippine Trench and the Philippine fault. This model predicts a velocity of 2 to 2.5 cm/yr along the fault. Geologic data from the Visayas provide an age of 2 to 4 Ma for the fault, an age in good agreement with the date of the beginning of subduction in the Philippine Trench. The origin of the Philippine fault would thus be the flip of subduction from west to east after the locking of convergence to the west by the collision of the Philippine mobile belt with the Eurasian margin.
Optimal Hydrofoil Kinematics for Tidal Energy Extraction
NASA Astrophysics Data System (ADS)
Frank, Sarah; Mandre, Shreyas; Franck, Jennifer
2013-11-01
The pitch and heave kinematics of an oscillating hydrofoil are explored for tidal energy extraction using 2D Direct Numerical Simulation in a non-inertial reference frame. The hydrofoil is modeled by an ellipse of aspect ratio 10 at a Reynolds number of 1000 in uniform freestream. Starting with sinusoidal motion in pitch and heave, the heaving magnitude, pitch angle, frequency, and phase angle between pitch and heave were varied. The optimal case had a maximum heave of .5 chord lengths, a maximum pitch angle of 75 degrees, a non-dimensional frequency of 0.15, and a phase of 90 degrees, which are consistent with similar computational studies, and parallel theory and experimentation. In order to further optimize the hydrofoil's stroke for fluid energy extraction, higher harmonics are systemically added to the kinematics, finding that small perturbations to the heave signal can increase the efficiency by up to 6.0%.
Identification of top quarks using kinematic variables
Abe, F.; Akimoto, H.; Akopian, A.; Albrow, M.G.; Amendolia, S.R.; Amidei, D.; Antos, J.; Anway-Wiese, C.; Aota, S.; Apollinari, G.; Asakawa, T.; Ashmanskas, W.; Atac, M.; Auchincloss, P.; Azfar, F.; Azzi-Bacchetta, P.; Bacchetta, N.; Badgett, W.; Bagdasarov, S.; Bailey, M.W.; Bao, J.; de Barbaro, P.; Barbaro-Galtieri, A.; Barnes, V.E.; Barnett, B.A.; Bartalini, P.; Bauer, G.; Baumann, T.; Bedeschi, F.; Behrends, S.; Belforte, S.; Bellettini, G.; Bellinger, J.; Benjamin, D.; Benlloch, J.; Bensinger, J.; Benton, D.; Beretvas, A.; Berge, J.P.; Bertolucci, S.; Bhatti, A.; Biery, K.; Binkley, M.; Bisello, D.; Blair, R.E.; Blocker, C.; Bodek, A.; Bokhari, W.; Bolognesi, V.; Bortoletto, D.; Boudreau, J.; Brandenburg, G.; Breccia, L.; Bromberg, C.; Buckley-Geer, E.; Budd, H.S.; Burkett, K.; Busetto, G.; Byon-Wagner, A.; Byrum, K.L.; Cammerata, J.; Campagnari, C.; Campbell, M.; Caner, A.; Carithers, W.; Carlsmith, D.; Castro, A.; Cauz, D.; Cen, Y.; Cervelli, F.; Chao, H.Y.; Chapman, J.; Cheng, M.; Chiarelli, G.; Chikamatsu, T.; Chiou, C.N.; Christofek, L.; Cihangir, S.; Clark, A.G.; Cobal, M.; Contreras, M.; Conway, J.; Cooper, J.; Cordelli, M.; Couyoumtzelis, C.; Crane, D.; Cronin-Hennessy, D.; Culbertson, R.; Cunningham, J.D.; Daniels, T.; DeJongh, F.; Delchamps, S.; Dell`Agnello, S.; Dell`Orso, M.; Demortier, L.; Denby, B.; Deninno, M.; Derwent, P.F.; Devlin, T.; Dickson, M.; Dittmann, J.R.; Donati, S.; Drucker, R.B.; Dunn, A.; Eddy, N.; Einsweiler, K.; Elias, J.E.; Ely, R.; Engels, E. Jr.; Errede, D.; Errede, S.; Fan, Q.; Fiori, I.; Flaugher, B.; Foster, G.W.; Franklin, M.; Frautschi, M.; Freeman, J.; Friedman, J.; Frisch, H.; Fuess, T.A.; Fukui, Y.; Funaki, S.; Gagliardi, G.; Galeotti, S.; Gallinaro, M.; Garcia-Sciveres, M.; Garfinkel, A.F.; Gay, C.; Geer, S.; Gerdes, D.W.; Giannetti, P.; Giokaris, N.; Giromini, P.; Gladney, L.; Glenzinski, D.; Gold, M.; Gonzalez, J.; Gordon, A.; Goshaw, A.T.; Goulianos, K.; Grassmann, H.; Groer, L.; Grosso-Pilcher, C.; CDF Collabora..
1995-09-01
We have used a kinematic technique to distinguish top quark pair production from background in {ital p{bar p}} collisions at {radical}{ital s}=1.8 TeV, applied to 67 pb{sup {minus}1} of data. We define a sample of {ital W}+{ge}3 jet events in which the jets are produced at large angles relative to the incident beams. In this sample, we find an excess of events with large jet transverse energies relative to expectations from background. The excess is consistent with top quark production; a large fraction of events in this kinematic region contains {ital b} jets. We interpret these results as evidence that most of the selected events are from {ital t{bar t}} decay.
A classification of finite quantum kinematics
NASA Astrophysics Data System (ADS)
Tolar, J.
2014-10-01
Quantum mechanics in Hilbert spaces of finite dimension N is reviewed from the number theoretic point of view. For composite numbers N possible quantum kinematics are classified on the basis of Mackey's Imprimitivity Theorem for finite Abelian groups. This yields also a classification of finite Weyl-Heisenberg groups and the corresponding finite quantum kinematics. Simple number theory gets involved through the fundamental theorem describing all finite discrete Abelian groups of order N as direct products of cyclic groups, whose orders are powers of not necessarily distinct primes contained in the prime decomposition of N. The representation theoretic approach is further compared with the algebraic approach, where the basic object is the corresponding operator algebra. The consideration of fine gradings of this associative algebra then brings a fresh look on the relation between the mathematical formalism and physical realizations of finite quantum systems.
Kinematics of swimming garter snakes (Thamnophis sirtalis).
Munk, Yonatan
2008-06-01
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
Internal Kinematics of Microstructures and Implications
Luis F. Miranda
2003-10-14
High resolution images at different wavelengths show the common presence of structures and microstructures in planetary nebulae (PNe), which are not well incorporated to the existing models for the formation of these objects. We summarize how studies of the internal kinematics, combined with the information provided by high resolution images, may help to establish the nature and possible origin of the observed structures as well as to provide information about the physical processes involved in the formation and evolution of PNe.
Kinematic structures in galactic disc simulations
NASA Astrophysics Data System (ADS)
Roca-Fàbrega, S.; Romero-Gómez, M.; Figueras, F.; Antoja, T.; Valenzuela, O.
2011-10-01
N-body and test particle simulations have been used to characterize the stellar streams in the galactic discs of Milky Way type galaxies. Tools such as the second and third order moments of the velocity ellipsoid and clustering methods -EM-WEKA and FoF- allow characterizing these kinematic structures and linking them to the stellar overdensities and to the resonant regions all through the disc.
Kinematics of 13 brightest cluster galaxies
NASA Astrophysics Data System (ADS)
Fisher, David; Illingworth, Garth; Franx, Marijn
1995-01-01
Velocity dispersion profiles and rotation curves have been determined for a sample of 13 brightest cluster galaxies (BCGs) in order to study their internal stellar kinematics and investigate their relationship to ellipticals. We find that BCGs generally display velocity dispersion profiles with gradients similar to those found in normal bright ellipticals. A rising velocity dispersion profile is found for the BCG IC 1101, the dominant member of Abell 2029, confirming Dressler's (1979) result. No other rising velocity dispersion profiles are found in our sample suggesting that they are not a feature common to brightest cluster galaxies. Significant rotation is found in only two of the galaxies, a result in agreement with previous studies showing the declining importance of rotation with increasing luminosity for elliptical galaxies. Our data suggest that environment plays a role in the kinematic characteristics of BCGs. We find a correlation between the rotation of BCGs and the velocity dispersion of their parent clusters in the sense that very slow rotating galaxies (Vm/(mean value of sigma))* less than 0.1, are predominantly found in high velocity dispersion (sigmacL greater than 650 km/s) clusters. This relation between the internal stellar kinematics of BCGs and the cluster velocity dispersion is in the sense expected if ellipticals formed by merging. Brightest cluster galaxy mass-to-light ratios derived from photometric and kinematic modeling are found to be similar to normal elliptical M/L values. For the galaxy NGC 4073, the dominant galaxy in the poor cluster MKW 4, we find that it contains a counterrotating stellar core suggestive of the occurrence of an accretion event(s).
Identification of top quarks using kinematic variables
F. Abe; H. Akimoto; A. Akopian; M. G. Albrow; S. R. Amendolia; D. Amidei; J. Antos; C. Anway-Wiese; S. Aota; G. Apollinari; T. Asakawa; W. Ashmanskas; M. Atac; P. Auchincloss; F. Azfar; P. Azzi-Bacchetta; N. Bacchetta; W. Badgett; S. Bagdasarov; M. W. Bailey; J. Bao; P. de Barbaro; A. Barbaro-Galtieri; V. E. Barnes; B. A. Barnett; P. Bartalini; G. Bauer; T. Baumann; F. Bedeschi; S. Behrends; S. Belforte; G. Bellettini; J. Bellinger; D. Benjamin; J. Benlloch; J. Bensinger; D. Benton; A. Beretvas; J. P. Berge; S. Bertolucci; A. Bhatti; K. Biery; M. Binkley; D. Bisello; R. E. Blair; C. Blocker; A. Bodek; W. Bokhari; V. Bolognesi; D. Bortoletto; J. Boudreau; G. Brandenburg; L. Breccia; C. Bromberg; E. Buckley-Geer; H. S. Budd; K. Burkett; G. Busetto; A. Byon-Wagner; K. L. Byrum; J. Cammerata; C. Campagnari; M. Campbell; A. Caner; W. Carithers; D. Carlsmith; A. Castro; D. Cauz; Y. Cen; F. Cervelli; H. Y. Chao; J. Chapman; M.-T. Cheng; G. Chiarelli; T. Chikamatsu; C. N. Chiou; L. Christofek; S. Cihangir; A. G. Clark; M. Cobal; M. Contreras; J. Conway; J. Cooper; M. Cordelli; C. Couyoumtzelis; D. Crane; D. Cronin-Hennessy; R. Culbertson; J. D. Cunningham; T. Daniels; F. Dejongh; S. Delchamps; L. Demortier; B. Denby; M. Deninno; P. F. Derwent; T. Devlin; M. Dickson; J. R. Dittmann; S. Donati; R. B. Drucker; A. Dunn; N. Eddy; K. Einsweiler; J. E. Elias; R. Ely; E. Jr. Engels; D. Errede; S. Errede; Q. Fan; I. Fiori; B. Flaugher; G. W. Foster; M. Franklin; M. Frautschi; J. Freeman; J. Friedman; H. Frisch; T. A. Fuess; Y. Fukui; S. Funaki; G. Gagliardi; S. Galeotti; M. Gallinaro; M. Garcia-Sciveres; A. F. Garfinkel; C. Gay; S. Geer; D. W. Gerdes; P. Giannetti; N. Giokaris; P. Giromini; L. Gladney; D. Glenzinski; M. Gold; J. Gonzalez; A. Gordon; A. T. Goshaw; K. Goulianos; H. Grassmann; L. Groer; C. Grosso-Pilcher; G. Guillian; R. S. Guo; C. Haber; S. R. Hahn; R. Handler; R. M. Hans; K. Hara; B. Harral; R. M. Harris; S. A. Hauger; J. Hauser; C. Hawk; E. Hayashi; J. Heinrich; M. Hohlmann; C. Holck; R. Hollebeek; L. Holloway; A. Ho; S. Hong; G. Houk; P. Hu; B. T. Huffman; R. Hughes; J. Huston; J. Huth; J. Hylen; H. Ikeda; M. Incagli; J. Incandela; J. Iwai; Y. Iwata; H. Jensen; U. Joshi; R. W. Kadel; E. Kajfasz; T. Kamon; T. Kaneko; K. Karr; H. Kasha; Y. Kato; L. Keeble; K. Kelley; R. D. Kennedy; R. Kephart; P. Kesten; D. Kestenbaum; R. M. Keup; H. Keutelian; F. Keyvan; B. J. Kim; D. H. Kim; H. S. Kim; S. B. Kim; S. H. Kim; Y. K. Kim; L. Kirsch; P. Koehn; K. Kondo; J. Konigsberg; S. Kopp; K. Kordas; W. Koska; E. Kovacs; W. Kowald; M. Krasberg; J. Kroll; M. Kruse; T. Kuwabara; S. E. Kuhlmann; E. Kuns; A. T. Laasanen; N. Labanca; S. Lammel; J. I. Lamoureux; T. Lecompte; S. Leone; J. D. Lewis; P. Limon; M. Lindgren; T. M. Liss; N. Lockyer; O. Long; C. Loomis; M. Loreti; J. Lu; D. Lucchesi; P. Lukens; S. Lusin; J. Lys; K. Maeshima; A. Maghakian; P. Maksimovic; M. Mangano; J. Mansour; M. Mariotti; J. P. Marriner; A. Martin; J. A. Matthews; R. Mattingly; P. McIntyre; P. Melese; A. Menzione; E. Meschi; S. Metzler; C. Miao; G. Michail; S. Mikamo; R. Miller; H. Minato; S. Miscetti; M. Mishina; H. Mitsushio; T. Miyamoto; S. Miyashita; Y. Morita; J. Mueller; A. Mukherjee; T. Muller; P. Murat; H. Nakada; I. Nakano; C. Nelson; D. Neuberger; C. Newman-Holmes; M. Ninomiya; L. Nodulman; S. Ogawa; S. H. Oh; K. E. Ohl; T. Ohmoto; T. Ohsugi; R. Oishi; M. Okabe; T. Okusawa; R. Oliver; J. Olsen; C. Pagliarone; R. Paoletti; V. Papadimitriou; S. P. Pappas; J. Patrick; G. Pauletta; M. Paulini; L. Pescara; M. D. Peters; T. J. Phillips; G. Piacentino; M. Pillai; K. T. Pitts; R. Plunkett; L. Pondrom; J. Proudfoot; F. Ptohos; G. Punzi; K. Ragan; A. Ribon; F. Rimondi; L. Ristori; W. J. Robertson; T. Rodrigo; J. Romano; L. Rosenson; R. Roser; W. K. Sakumoto; D. Saltzberg; L. Santi; H. Sato; V. Scarpine; P. Schlabach; E. E. Schmidt; M. P. Schmidt; G. F. Sciacca; A. Scribano; S. Segler; S. Seidel; Y. Seiya; G. Sganos; A. Sgolacchia; M. D. Shapiro; N. M. Shaw; Q. Shen; P. F. Shepard; M. Shimojima; M. Shochet; J. Siegrist; A. Sill; P. Sinervo; P. Singh; J. Skarha; K. Sliwa; D. A. Smith; F. D. Snider; T. Song; J. Spalding; P. Sphicas; L. Spiegel; A. Spies; L. Stanco; J. Steele; A. Stefanini; K. Strahl; J. Strait; D. Stuart; G. Sullivan; A. Soumarokov; K. Sumorok; J. Suzuki; T. Takada; T. Takahashi; T. Takano; K. Takikawa; N. Tamura; F. Tartarelli; W. Taylor; P. K. Teng; Y. Teramoto; S. Tether; D. Theriot; T. L. Thomas; R. Thun; M. Timko; P. Tipton; A. Titov; S. Tkaczyk; D. Toback; K. Tollefson; A. Tollestrup; J. Tonnison; J. F. de Troconiz; S. Truitt; J. Tseng; N. Turini; T. Uchida; N. Uemura; F. Ukegawa; G. Unal; S. C. van den Brink; S. Vejcik; G. Velev; R. Vidal; M. Vondracek; D. Vucinic; R. G. Wagner; R. L. Wagner; J. Wahl; R. C. Walker; C. Wang; G. Wang; J. Wang; M. J. Wang; Q. F. Wang; A. Warburton; G. Watts; T. Watts; R. Webb; C. Wei; C. Wendt
1995-01-01
We have used a kinematic technique to distinguish top quark pair production from background in pp¯ collisions at &surd;s=1.8 TeV, applied to 67 pb-1 of data. We define a sample of W+>=3 jet events in which the jets are produced at large angles relative to the incident beams. In this sample, we find an excess of events with large jet
Kinematic GPS positioning in a highway environment
Li, Yingfeng
1994-01-01
. Relationship between ionospheric delay and epoch time observed from the fixed receiver 12. Relationship between ionospheric delay and epoch time observed from the moving receiver 13. The result of kinematic GPS positioning using Ll carrier phase 14... to solve for cycle slips, orbit precision improvement techniques, and the modeling of the ionospheric effects in single frequency measurements. There are, however, many applications where the relative position of a moving vehicle, ship or aircraft...
Kinematics of Hooke universal joint robot wrists
NASA Technical Reports Server (NTRS)
Mckinney, William S., Jr.
1988-01-01
The singularity problem associated with wrist mechanisms commonly found on industrial manipulators can be alleviated by redesigning the wrist so that it functions as a three-axis gimbal system. This paper discussess the kinematics of gimbal robot wrists made of one and two Hooke universal joints. Derivations of the resolved rate motion control equations for the single and double Hooke universal joint wrists are presented using the three-axis gimbal system as a theoretical wrist model.
The Galactic Kinematics of Mira Variables
Michael Feast
2002-07-09
The galactic kinematics of Mira variables derived from radial velocities, Hipparcos proper motions and an infrared period-luminosity relation are reviewed. Local Miras in the 145-200day period range show a large asymmetric drift and a high net outward motion in the Galaxy. Interpretations of this phenomenon are considered and (following Feast and Whitelock 2000) it is suggested that they are outlying members of the bulge-bar population and indicate that this bar extends beyond the solar circle.
Kinematic adaptations to tripedal locomotion in dogs.
Goldner, B; Fuchs, A; Nolte, I; Schilling, N
2015-05-01
Limb amputation often represents the only treatment option for canine patients with certain diseases or injuries of the appendicular system. Previous studies have investigated adaptations to tripedal locomotion in dogs but there is a lack of understanding of biomechanical compensatory mechanisms. This study evaluated the kinematic differences between quadrupedal and tripedal locomotion in nine healthy dogs running on a treadmill. The loss of the right pelvic limb was simulated using an Ehmer sling. Kinematic gait analysis included spatio-temporal comparisons of limb, joint and segment angles of the remaining pelvic and both thoracic limbs. The following key parameters were compared between quadrupedal and tripedal conditions: angles at touch-down and lift-off, minimum and maximum joint angles, plus range of motion. Significant differences in angular excursion were identified in several joints of each limb during both stance and swing phases. The most pronounced differences concerned the remaining pelvic limb, followed by the contralateral thoracic limb and, to a lesser degree, the ipsilateral thoracic limb. The thoracic limbs were, in general, more retracted, consistent with pelvic limb unloading and previous observations of bodyweight re-distribution in amputees. Proximal limb segments showed more distinct changes than distal ones. Particularly, the persistently greater anteversion of the pelvis probably affects the axial system. Overall, tripedal locomotion requires concerted kinematic adjustments of both the appendicular and axial systems, and consequently preventive, therapeutic and rehabilitative care of canine amputees should involve the whole musculoskeletal apparatus. PMID:25862392
New Kinematical Constraints on Cosmic Acceleration
Rapetti, David; Allen, Steve W.; Amin, Mustafa A.; Blandford, Roger; /-KIPAC, Menlo Park
2007-05-25
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.
Computational tool for comparison of kinematic mechanisms and commonly used kinematic models
Hollerbach, K.; Hollister, A.M.; Van Vorhis, R.L.
1997-03-01
Accurate, reliable, and reproducible methods to measure the movements of human joints have been elusive. Currently, three-dimensional recording methods are used to track the motion of one segment relative to another as the joint moves. Six parameters describe the moving segment`s location and orientation relative to the reference segment: three translations (x, y, and z) and three rotations (yaw, pitch and roll) in the reference frame. The raw data can be difficult to interpret. For this reason, several methods have been developed to measure the motion of human joints and to describe the resulting data. For example, instant helical axes or screw deviation axes (Kinzell et al., 1972), the Joint Coordinate System of Grood and Suntay (1983), and the Euler angle method have been used to describe the movements of bones relative to each other. None of these methods takes into account the physical kinematic mechanism producing the joint motion. More recently, Lupichuk (1995) has developed an algorithm to find, for an arbitrary revolute, the axis` position and orientation in three- dimensional space. Each of these methods has advantages and disadvantages in analyzing joint kinematics. The authors have developed software to provide a means of comparing these methods for arbitrary, single degree of freedom, kinematic mechanisms. Our objective is to demonstrate the software and to show how it can be used to compare the results from the different kinematic models as they are applied to specific kinematic mechanisms.
Improved Klett lidar inversion techniques
NASA Astrophysics Data System (ADS)
Lentz, William J.; Cooper, Alfred W.; Regush, M. M.
1994-06-01
Realistic inversions of lidar signals for extinction using the Klett technique must take into account both the theoretical limitations of the inversion and the experimental constraints of the hardware. A simple test of the Klett inversion algorithm s19 is performed with and without experimental limitations and uncertainties. The effect of limited accuracy in the digitization of the lidar return and limited dynamic range is presented. A simplified technique for detecting clouds in the presence of low visiblity is developed, and some limitations are presented.
Inversion of simulated satellite signals
NASA Astrophysics Data System (ADS)
Kaestner, Martina
1987-03-01
The inversion of simulated lidar signals from space was investigated. Profiles of atmospheric extinction coefficients were determined from lidar signals with high vertical resolution. The examination of the sensitivity of inversion algorithms for backscatter profiles shows that the otherwise advantageous Klett algorithm has disadvantages if applied to satellite lidar signals. Because the dependence of the extinction profiles on the lidar quotient and the extinction coefficient of the air layer close to the soil is so large, an iterative inversion algorithm was developed. It has a small dependence on a priori unknown quantities.
Givental graphs and inversion symmetry
P. Dunin-Barkowski; S. Shadrin; L. Spitz
2012-12-17
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.
Inverse thermoremanent magnetization
NASA Astrophysics Data System (ADS)
Dunlop, David J.
2006-12-01
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.
Salinger, Andy [Sandia National Laboratories (SNL); Evans, Katherine J [ORNL; Lemieux, Jean-Francois [New York University; Holland, David [New York University; Payne, Tony [University of Bristol, UK; Price, Stephen [Los Alamos National Laboratory (LANL); Knoll, Dana [Los Alamos National Laboratory (LANL)
2011-01-01
We have implemented the Jacobian-free Newton-Krylov (JFNK) method for solving the rst-order ice sheet momentum equation in order to improve the numerical performance of the Community Ice Sheet Model (CISM), the land ice component of the Community Earth System Model (CESM). Our JFNK implementation is based on signicant re-use of existing code. For example, our physics-based preconditioner uses the original Picard linear solver in CISM. For several test cases spanning a range of geometries and boundary conditions, our JFNK implementation is 1.84-3.62 times more efficient than the standard Picard solver in CISM. Importantly, this computational gain of JFNK over the Picard solver increases when rening the grid. Global convergence of the JFNK solver has been signicantly improved by rescaling the equation for the basal boundary condition and through the use of an inexact Newton method. While a diverse set of test cases show that our JFNK implementation is usually robust, for some problems it may fail to converge with increasing resolution (as does the Picard solver). Globalization through parameter continuation did not remedy this problem and future work to improve robustness will explore a combination of Picard and JFNK and the use of homotopy methods.
Banded matrices with banded inverses
Srinivasa Gopala Raghavan, Venugopalan
2010-01-01
We discuss the conditions that are necessary for a given banded matrix to have a banded inverse. Although a generic requirement is known from previous studies, we tend to focus on the ranks of the block matrices that are ...
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.
Action understanding as inverse planning
Baker, Christopher Lawrence
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 ...
Computation of inverse magnetic cascades
NASA Technical Reports Server (NTRS)
Montgomery, D.
1981-01-01
Inverse cascades of magnetic quantities for turbulent incompressible magnetohydrodynamics are reviewed, for two and three dimensions. The theory is extended to the Strauss equations, a description intermediate between two and three dimensions appropriate to Tokamak magnetofluids. Consideration of the absolute equilibrium Gibbs ensemble for the system leads to a prediction of an inverse cascade of magnetic helicity, which may manifest itself as a major disruption. An agenda for computational investigation of this conjecture is proposed.
NASA Astrophysics Data System (ADS)
Hou, W.; Wang, J.; Xu, X.; Ding, S.; Han, D.; Leitch, J. W.; Delker, T.; Chen, G.
2014-12-01
This paper presents an inversion method to retrieve aerosol properties from the hyperspectral data collected by airborne GeoTASO (Geostationary Trance gas and Aerosol Sensor Optimization). Mounted on the NASA HU-25C aircraft, GeoTASO measures radiation in 1000 spectral bands from 415 nm to 696 nm, and is a prototype for the TEMPO (Tropospheric Emissions: Monitoring of Pollution) instrument. It flew over Houston during September 2013 and gathered several days' of airborne hyperspectral remote sensing data for our research. Our inversion method, which is based on the optimization theory and different from the traditional lookup table (LUT) retrieval technique, can simultaneously retrieve parameters of atmospheric aerosols such as the aerosol optical depth and other aerosol parameters, as well as the surface reflectance albedo. To provide constraints of hyperspectral surface reflectance in the inversion, we first conduct principal component analysis (PCA) using 46 reflectance spectra of various plants and vegetation to identify the most influential components. With the first six principal components and the corresponding calculated weight vector, the spectra could be reconstructed with an accuracy of 1%. UNL-VRTM (UNified Linearized Radiative Transfer Model) is employed for forward model calculation, and its outputs include not only the Stokes 4-vector elements, but also their sensitivities (Jacobians) with respect to the aerosol properties parameters and the principal components of surface spectral reflectance. The inversion is carried out with optimization algorithm L-BFGS-B (Large scale BFGS Bound constrained), and is conducted iteratively until the modeled spectral radiance fits with GeoTASO measurements. Finally, the retrieval results of aerosol optical depth and other aerosol parameters are compared against those retrieved by AEROENT and/or in situ measurements during the aircraft campaign.
Athletic Footwear, Leg Stiffness, and Running Kinematics
Bishop, Mark; Fiolkowski, Paul; Conrad, Bryan; Brunt, Denis; Horodyski, MaryBeth
2006-01-01
Context: The leg acts as a linear spring during running and hopping and adapts to the stiffness of the surface, maintaining constant total stiffness of the leg-surface system. Introducing a substance (eg, footwear) may affect the stiffness of the leg in response to changes in surface stiffness. Objective: To determine if the type of athletic footwear affects the regulation of leg stiffness in dynamic activities. Design: Repeated-measures design. Setting: Motion analysis laboratory. Patients or Other Participants: Nine healthy adults (age = 28 ± 6.8 years, mass = 71.6 ± 12.9 kg) free from lower extremity injuries. Intervention(s): Subjects hopped at 2.2 Hz on a forceplate under 3 footwear conditions (barefoot, low-cost footwear, high-cost footwear). Subjects ran on a treadmill at 2 speeds (2.23 m/s, 3.58 m/s) under the same footwear conditions. Main Outcome Measure(s): Limb stiffness was calculated from forceplate data. Kinematic data (knee and ankle angles at initial contact and peak joint excursion after contact) were collected during running. We calculated 1-way repeated-measures (stiffness) and 2-way (speed by footwear) repeated-measures analyses of variance (running kinematics) to test the dependent variables. Results: A significant increase in leg stiffness from the barefoot to the “cushioned” shoe condition was noted during hopping. When running shod, runners landed in more dorsiflexion but had less ankle motion than when running barefoot. No differences were seen between the types of shoes. The primary kinematic difference was identified as running speed increased: runners landed in more knee flexion. At the ankle, barefoot runners increased ankle motion to a significantly greater extent than did shod runners as speed increased. Conclusions: Footwear influences the maintenance of stiffness in the lower extremity during hopping and joint excursion at the ankle in running. Differences in cushioning properties of the shoes tested did not appear to be significant. PMID:17273463
Kinematics of transition during human accelerated sprinting
Nagahara, Ryu; Matsubayashi, Takeo; Matsuo, Akifumi; Zushi, Koji
2014-01-01
ABSTRACT This study investigated kinematics of human accelerated sprinting through 50?m and examined whether there is transition and changes in acceleration strategies during the entire acceleration phase. Twelve male sprinters performed a 60-m sprint, during which step-to-step kinematics were captured using 60 infrared cameras. To detect the transition during the acceleration phase, the mean height of the whole-body centre of gravity (CG) during the support phase was adopted as a measure. Detection methods found two transitions during the entire acceleration phase of maximal sprinting, and the acceleration phase could thus be divided into initial, middle, and final sections. Discriminable kinematic changes were found when the sprinters crossed the detected first transition—the foot contacting the ground in front of the CG, the knee-joint starting to flex during the support phase, terminating an increase in step frequency—and second transition—the termination of changes in body postures and the start of a slight decrease in the intensity of hip-joint movements, thus validating the employed methods. In each acceleration section, different contributions of lower-extremity segments to increase in the CG forward velocity—thigh and shank for the initial section, thigh, shank, and foot for the middle section, shank and foot for the final section—were verified, establishing different acceleration strategies during the entire acceleration phase. In conclusion, there are presumably two transitions during human maximal accelerated sprinting that divide the entire acceleration phase into three sections, and different acceleration strategies represented by the contributions of the segments for running speed are employed. PMID:24996923
A Kinematical Approach to Dark Energy Studies
Rapetti, David; Allen, Steven W.; Amin, Mustafa A.; Blandford, Roger D.; /KIPAC, Menlo Park
2006-06-06
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.
Automobile Collisions, Kinematics and Related Injury Patterns
Siegel, A. W.
1972-01-01
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. PMID:5059661
Mapping Dark Matter Halos with Stellar Kinematics
NASA Astrophysics Data System (ADS)
Murphy, Jeremy; Gebhardt, K.; Greene, J. E.; Graves, G.
2013-07-01
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.
Quantum simulation of noncausal kinematic transformations.
Alvarez-Rodriguez, U; Casanova, J; Lamata, L; Solano, E
2013-08-30
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
Kinematic Design to Improve Ergonomics in Human Machine Interaction
André Schiele; Frans C. T. van der Helm
2006-01-01
This paper introduces a novel kinematic design paradigm for ergonomic human machine interaction. Goals for optimal design are formulated generically and applied to the mechanical design of an upper-arm exoskeleton. A nine degree-of-freedom (DOF) model of the human arm kinematics is presented and used to develop, test, and optimize the kinematic structure of an human arm interfacing exoskeleton. The resulting
Weighted Inverse Gaussian -a Versatile Lifetime Model
Kundu, Debasis
-parameter generalized inverse Gaussian distribution, which is a mixture of the inverse Gaussian distribution and lengthWeighted Inverse Gaussian - a Versatile Lifetime Model Ramesh C. Gupta1 & Debasis Kundu2 Abstract biased inverse Gaussian distri- bution. Also Birnbaum-Saunders distribution is a special case for p = 1
Prestack seismic inversion and reservoir property prediction
Xingang Chi
2008-01-01
In this dissertation, I have applied the method of prestack seismic inversion with uncertainty analysis. Also, I have developed the methods of the rock physics template analysis, the fluid modulus inversion and the reservoir property inversion from AVO attributes with and without constraint to improve the technique of reservoir characterization. I use the prestack seismic inversion to invert the elastic
TWO UNCONVENTIONAL APPROACHES TO ELECTROMAGNETIC INVERSION
Snieder, Roel
the feasibility of the inverse scattering series, which can effectively resolve the nonlinearity of an inverse problem, for the interpretation of electromagnetic data. The application of the inverse scat- tering to the true model. This study quantifies convergence conditions of the inverse scattering series and suggests
Kinematic GPS Profiles to monitor surface deformation
NASA Astrophysics Data System (ADS)
Charara, R.; Vigny, C.; Briole, P.
2008-12-01
GPS kinematic measurement consists in placing a GPS rover receiver that registers its position on a moving vehicule with a high frequency. The frequency of the data acquisition is chosen according to the number of points and the precision needed to characterize the rover trajectory. The position of the rover receiver can be determined with respect to another GPS reference station with a precision of a few centimeters. Consequently different kinematic profiles on trajectories can be realized in different contexts (volcano slopes, active faults,...). We first studied the correlation between different profiles on the same trajectory in the absense of any particular event. Then different individual profiles are interpolated and a single profiles is generated which we refer to as "tube". We also studied and analyzed the impact of different parameters such as the baseline length, the atmospheric errors and the number of individual profiles on the precision of the obtained tube. We present results of experimentations that were performed in Chili, Reunion Island and Greece and we show how the results can be influenced by the baselines lengths and topographies. In case of event (Earthquakes, volcanoes eruptions, landslides,...) this technique can be used to assess the amplitude of ground deformation. We estimate the thresholds (in term of amplitude and spatial extension) of detectable signals.
Friction Stir Welding at MSFC: Kinematics
NASA Technical Reports Server (NTRS)
Nunes, A. C., Jr.
2001-01-01
In 1991 The Welding Institute of the United Kingdom patented the Friction Stir Welding (FSW) process. In FSW a rotating pin-tool is inserted into a weld seam and literally stirs the faying surfaces together as it moves up the seam. By April 2000 the American Welding Society International Welding and Fabricating Exposition featured several exhibits of commercial FSW processes and the 81st Annual Convention devoted a technical session to the process. The FSW process is of interest to Marshall Space Flight Center (MSFC) as a means of avoiding hot-cracking problems presented by the 2195 aluminum-lithium alloy, which is the primary constituent of the Lightweight Space Shuttle External Tank. The process has been under development at MSFC for External Tank applications since the early 1990's. Early development of the FSW process proceeded by cut-and-try empirical methods. A substantial and complex body of data resulted. A theoretical model was wanted to deal with the complexity and reduce the data to concepts serviceable for process diagnostics, optimization, parameter selection, etc. A first step in understanding the FSW process is to determine the kinematics, i.e., the flow field in the metal in the vicinity of the pin-tool. Given the kinematics, the dynamics, i.e., the forces, can be targeted. Given a completed model of the FSW process, attempts at rational design of tools and selection of process parameters can be made.
Kinematics of unconstrained tactile texture exploration.
Callier, Thierri; Saal, Hannes P; Davis-Berg, Elizabeth C; Bensmaia, Sliman J
2015-04-01
A hallmark of tactile texture exploration is that it involves movement between skin and surface. When we scan a surface, small texture-specific vibrations are produced in the skin, and specialized cutaneous mechanoreceptors convert these vibrations into highly repeatable, precise, and informative temporal spiking patterns in tactile afferents. Both texture-elicited vibrations and afferent responses are highly dependent on exploratory kinematics, however; indeed, these dilate or contract systematically with decreases or increases in scanning speed, respectively. These profound changes in the peripheral response that accompany changes in scanning speed and other parameters of texture scanning raise the question as to whether exploratory behaviors change depending on what surface is explored or what information is sought about that surface. To address this question, we measure and analyze the kinematics as subjects explore textured surfaces to evaluate different types of texture information, namely the textures' roughness, hardness, and slipperiness. We find that the exploratory movements are dependent both on the perceptual task, as has been previously shown, but also on the texture that is scanned. We discuss the implications of our findings regarding the neural coding and perception of texture. PMID:25744883
Nuclear Rings in Galaxies - A Kinematic Perspective
NASA Technical Reports Server (NTRS)
Mazzuca, Lisa M.; Swaters, Robert A.; Knapen, Johan H.; Veilleux, Sylvain
2011-01-01
We combine DensePak integral field unit and TAURUS Fabry-Perot observations of 13 nuclear rings to show an interconnection between the kinematic properties of the rings and their resonant origin. The nuclear rings have regular and symmetric kinematics, and lack strong non-circular motions. This symmetry, coupled with a direct relationship between the position angles and ellipticities of the rings and those of their host galaxies, indicate the rings are in the same plane as the disc and are circular. From the rotation curves derived, we have estimated the compactness (v(sup 2)/r) up to the turnover radius, which is where the nuclear rings reside. We find that there is evidence of a correlation between compactness and ring width and size. Radially wide rings are less compact, and thus have lower mass concentration. The compactness increases as the ring width decreases. We also find that the nuclear ring size is dependent on the bar strength, with weaker bars allowing rings of any size to form.
K to pi pi Amplitudes at Unphysical Kinematics Using Domain Wall Fermions
Matthew Lightman
2007-11-26
The use of chiral perturbation theory in extracting physical K to pi pi matrix elements from matrix elements calculated at unphysical kinematics is outlined. In particular, the possibility of utilizing pions with non-zero momentum in the final state, and of using partial quenching is discussed. Preliminary (not physically normalized) Delta I=3/2 (27,1) K to pi pi matrix elements are calculated on the RBC/UKQCD $24^3 \\times 64$, $L_s=16$ lattices, using 2+1 dynamical flavors and domain wall fermions, with an inverse lattice spacing of $a^{-1}=1.729(28) GeV$. Effective mass plots are presented for a light sea quark mass of $m_l^{sea}=0.005$, and various valence quark masses. The plateaux are fit and $E_{\\pi\\pi}-m_K$ is extracted.
Kinematic modeling of a double octahedral Variable Geometry Truss (VGT) as an extensible gimbal
NASA Technical Reports Server (NTRS)
Williams, Robert L., II
1994-01-01
This paper presents the complete forward and inverse kinematics solutions for control of the three degree-of-freedom (DOF) double octahedral variable geometry truss (VGT) module as an extensible gimbal. A VGT is a truss structure partially comprised of linearly actuated members. A VGT can be used as joints in a large, lightweight, high load-bearing manipulator for earth- and space-based remote operations, plus industrial applications. The results have been used to control the NASA VGT hardware as an extensible gimbal, demonstrating the capability of this device to be a joint in a VGT-based manipulator. This work is an integral part of a VGT-based manipulator design, simulation, and control tool.
Jung, Yihwan; Jung, Moonki; Lee, Kunwoo; Koo, Seungbum
2014-08-22
Kinetic analysis of walking requires joint kinematics and ground reaction force (GRF) measurement, which are typically obtained from a force plate. GRF is difficult to measure in certain cases such as slope walking, stair climbing, and track running. Nevertheless, estimating GRF continues to be of great interest for simulating human walking. The purpose of the study was to develop reaction force models placed on the sole of the foot to estimate full GRF when only joint kinematics are provided (Type-I), and to estimate ground contact shear forces when both joint kinematics and foot pressure are provided (Type-II and Type-II-val). The GRF estimation models were attached to a commercial full body skeletal model using the AnyBody Modeling System, which has an inverse dynamics-based optimization solver. The anterior-posterior shear force and medial-lateral shear force could be estimated with approximate accuracies of 6% BW and 2% BW in all three methods, respectively. Vertical force could be estimated in the Type-I model with an accuracy of 13.75% BW. The accuracy of the force estimation was the highest during the mid-single-stance period with an average RMS for errors of 3.10% BW, 1.48% BW, and 7.48% BW for anterior-posterior force, medial-lateral force, and vertical force, respectively. The proposed GRF estimation models could predict full and partial GRF with high accuracy. The design of the contact elements of the proposed model should make it applicable to various activities where installation of a force measurement system is difficult, including track running and treadmill walking. PMID:24917473
Deployable antenna kinematics using tensegrity structure design
NASA Astrophysics Data System (ADS)
Knight, Byron Franklin
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.
Kinematic Signatures of Telic and Atelic Events in ASL Predicates
ERIC Educational Resources Information Center
Malaia, Evie; Wilbur, Ronnie B.
2012-01-01
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…
Thermal and Kinematic Evolution of the Eastern Cordillera Fold and
Toro, Jaime
Thermal and Kinematic Evolution of the Eastern Cordillera Fold and Thrust Belt, Colombia Jaime Toro and then calculated the conductive thermal state of key steps of the kinematic history using ThrustpackR 4.0. The models were constrained by well, seismic, apatite fission-track, and thermal-maturity data. The main
KINEMATIC MAPPING APPLICATION TO APPROXIMATE TYPE AND DIMENSION
Hayes, John
the focus of a significant volume of research; in particular, robots whose mechanical systems are parallel approach for kinematic synthesis of planar parallel robots with three degrees-of- freedom (DOF). MurrayKINEMATIC MAPPING APPLICATION TO APPROXIMATE TYPE AND DIMENSION SYNTHESIS OF PLANAR MECHANISMS M
Online Learning of Humanoid Robot Kinematics Under Switching Tools Contexts
Instituto de Sistemas e Robotica
Online Learning of Humanoid Robot Kinematics Under Switching Tools Contexts Lorenzo Jamone1, Bruno different hidden contexts. To do that, we employ IMLE, a recent online learning algorithm that fits, a performance comparable to state-of-the-art online learning algorithms. The context varying forward kinematics
Determination of the stiffness of rolling kinematic pairs of manipulators
Przemys?aw Szumi?ski
2007-01-01
A method of determination of the radial and axial stiffness of rolling bearings and rolling kinematic pairs as a function of the external load and the kinematics of motion has been presented. In this method, an influence of the distribution of rolling elements during the bearing raceway motion (with respect to the direction the resultant vector of the radial load
Continuous kinematic wave models of merging traffic flow
Wen-Long Jin
2010-01-01
Merging junctions are important network bottlenecks, and a better understanding of merging traffic dynamics has both theoretical and practical implications. In this paper, we present continuous kinematic wave models of merging traffic flow which are consistent with discrete Cell Transmission Models with various distribution schemes. In particular, we develop a systematic approach to constructing kinematic wave solutions to the Riemann
On the kinematic analysis of geared robotic wrists
Ettore Pennestrì
1991-01-01
Geared robotic wrists are often mounted on heavy duty robots with high dexterity. Although these devices have only recently been adopted in industrial practice, systematic studies on their kinematic structure and design methodologies have already been initiated. In this paper parametric equations, to be used for the automated kinematic analysis of such mechanical systems, have been deduced. The formulation of
Limiting-case Analysis of Continuum Trunk Kinematics
Bryan A. Jones; Ian D. Walker
2007-01-01
Continuum robotic manipulators, termed trunks, mimic the astounding capabilities of elephant trunks and octopus arms by bending in smooth arcs. Several approaches to kinematic analysis of continuum trunks complement a wide variety of available continuum robots. However, these kinematics exhibit singularity-like conditions when the trunk assumes a straight posture, which is essential to complete many tasks. The novel limiting-case analysis
A School Experiment in Kinematics: Shooting from a Ballistic Cart
ERIC Educational Resources Information Center
Kranjc, T.; Razpet, N.
2011-01-01
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…
Inversion of ultrasonic scattering data
Rose, J.H.; Opsal, J.L.
1981-01-01
The elastic wave inverse scattering problem is examined from the point of view of the Inverse Born Approximation (IBA). It is shown that the IBA yields highly accurate results for the shape of complex composite voids given sufficient scattering data. The IBA is shown to provide accurate determinations for the size and shape of simple cracks and for a composite flaw which consists of a void with a circumferential crack. The Born approximation is also shown to provide a means for determining the composition of inclusions.
Population inversion by chirped pulses
Lu Tianshi [Department of Mathematics and Statistics, Wichita State University, Wichita, Kansas 67260-0033 (United States)
2011-09-15
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.
Multiphase inverse modeling: An Overview
Finsterle, S.
1998-03-01
Inverse modeling is a technique to derive model-related parameters from a variety of observations made on hydrogeologic systems, from small-scale laboratory experiments to field tests to long-term geothermal reservoir responses. If properly chosen, these observations contain information about the system behavior that is relevant to the performance of a geothermal field. Estimating model-related parameters and reducing their uncertainty is an important step in model development, because errors in the parameters constitute a major source of prediction errors. This paper contains an overview of inverse modeling applications using the ITOUGH2 code, demonstrating the possibilities and limitations of a formalized approach to the parameter estimation problem.
Combining asymptotic linearized inversion and full waveform inversion
NASA Astrophysics Data System (ADS)
Métivier, L.; Brossier, R.; Virieux, J.
2015-06-01
A method for combining the asymptotic operator designed by Beylkin (Born migration operator) for the solution of linearized inverse problems with full waveform inversion is presented. This operator is used to modify the standard L2 norm that measures the distance between synthetic and observed data. The modified misfit function measures the discrepancy of the synthetic and observed data after they have been migrated using the Beylkin operator. The gradient of this new misfit function is equal to the cross-correlation of the single scattering data with migrated/demigrated residuals. The modified misfit function possesses a Hessian operator that tends asymptotically towards the identity operator. The trade-offs between discrete parameters are thus reduced in this inversion scheme. Results on 2-D synthetic case studies demonstrate the fast convergence of this inversion method in a migration regime. From an accurate estimation of the initial velocity, three and five iterations only are required to generate high-resolution P-wave velocity estimation models on the Marmousi 2 and synthetic Valhall case studies.
Numerical analysis of kinematic soil-pile interaction
Castelli, Francesco; Maugeri, Michele [Department of Civil and Environmental Engineering, University of Catania, Viale Andrea Doria no. 6, 95125, Catania (Italy); Mylonakis, George [Department of Civil Engineering, University of Patras, Rio GR-26500, Patras (Greece)
2008-07-08
In the present study, the response of singles pile to kinematic seismic loading is investigated using the computer program SAP2000. The objectives of the study are: (1) to develop a numerical model that can realistically simulate kinematic soil-structure interaction for piles accounting for discontinuity conditions at the pile-soil interface, energy dissipation and wave propagation; (2) to use the model for evaluating kinematic interaction effects on pile response as function of input ground motion; and (3) to present a case study in which theoretical predictions are compared with results obtained from other formulations. To evaluate the effects of kinematic loading, the responses of both the free-field soil (with no piles) and the pile were compared. Time history and static pushover analyses were conducted to estimate the displacement and kinematic pile bending under seismic loadings.
Effective kinematic viscosity of turbulent He II
Chagovets, T. V.; Gordeev, A. V. [Institute of Physics ASCR, v.v.i., Na Slovance 2, 182 21 Prague (Czech Republic); Skrbek, L. [Faculty of Mathematics and Physics, Charles University, V Holesovickach 2, 180 00 Prague (Czech Republic)
2007-08-15
The temperature dependence of the effective kinematic viscosity of turbulent He II, {nu}{sub eff}(T), is deduced from second sound attenuation data using the late stage of decay of thermally induced counterflow He II turbulence in two channels of square cross section. It is shown to qualitatively agree with the published data for {nu}{sub eff}(T) calculated based on experiments on decaying-grid-generated He II turbulence [Niemela et al., J. Low Temp. Phys. 138, 537 (2005)]. Corrections to these data due to the 'sine squared' law that describes attenuation of the second sound wave propagating along an arbitrary direction with respect to the direction of the core of a quantized vortex in turbulent He II are discussed and applied.
Validation of a kinematic laserscanning system
NASA Astrophysics Data System (ADS)
Vennegeerts, Harald; Martin, Jens; Becker, Matthias; Kutterer, Hansjörg
2008-08-01
The increasing data rate of actual laser scanners qualifies these sensors for kinematic applications. In case of surveying static environments the scanner can be integrated into a moving platform system. Therefore two main tasks are outstanding. Position and orientation of the platform have to be registered throughout a freely driven trajectory. The second challenge is to synchronize the scanned spatial data with the time scale of the positioning unit. This paper presents the specification of a mobile mapping system using a phase-based laser scanner with a hybrid INS (Inertial Navigation System)/GPS solution. Among a description of the system structure it includes a software-based method to synchronize the scanned profiles with the trajectory. No extra hardware unit for time registration of scanned profiles is required. After all a spatial comparison of independently observed control points allows the assessment of the system performance.
Reproducing the kinematics of damped Lyman ? systems
NASA Astrophysics Data System (ADS)
Bird, Simeon; Haehnelt, Martin; Neeleman, Marcel; Genel, Shy; Vogelsberger, Mark; Hernquist, Lars
2015-02-01
We examine the kinematic structure of damped Lyman ? systems (DLAs) in a series of cosmological hydrodynamic simulations using the AREPO code. We are able to match the distribution of velocity widths of associated low-ionization metal absorbers substantially better than earlier work. Our simulations produce a population of DLAs dominated by haloes with virial velocities around 70 km s-1, consistent with a picture of relatively small, faint objects. In addition, we reproduce the observed correlation between velocity width and metallicity and the equivalent width distribution of Si II. Some discrepancies of moderate statistical significance remain; too many of our spectra show absorption concentrated at the edge of the profile and there are slight differences in the exact shape of the velocity width distribution. We show that the improvement over previous work is mostly due to our strong feedback from star formation and our detailed modelling of the metal ionization state.
Kinematic characteristics of hailstorms in Northern Greece
NASA Astrophysics Data System (ADS)
Foris, D. V.; Karacostas, T. S.; Flocas, A. A.; Makrogiannis, T. I.
2006-02-01
The purpose of this study is the analysis of radar data, digitally recorded, during an operational hail suppression program in the region of Central Macedonia, Greece, for the warm period of the years 1997-2001. Kinematic characteristics, such as lifetime and distance traveled by hailstorms, as well as direction of motion and speed, have been related to type of storms and season. It has been found that singlecells are short-lived and travel short distances, while multicells are long-lived and travel long distances. On the contrary, their corresponding speed distributions are similar. The deviation of the direction of motion from mean wind is smaller for singlecells than for multicells. September and July exhibit the maximum and minimum average storm speeds as a direct implication of synoptic disturbances passage and convection, prevailing respectively. Finally, storms overcoming orographic barriers decelerate in general on the windward side and accelerate on the lee side of mountains.
Kinematical Foundations of Loop Quantum Cosmology
Christian Fleischhack
2015-05-17
First, we review the $C^\\ast$-algebraic foundations of loop quantization, in particular, the construction of quantum configuration spaces and the implementation of symmetries. Then, we apply these results to loop quantum gravity, focusing on the space of generalized connections and on measures thereon. Finally, we study the realm of homogeneous isotropic loop quantum cosmology: once viewed as the loop quantization of classical cosmology, once seen as the symmetric sector of loop quantum gravity. It will turn out that both theories differ, i.e., quantization and symmetry reduction do not commute. Moreover, we will present a uniqueness result for kinematical measures. These last two key results have originally been due to Hanusch; here, we give drastically simplified and direct proofs.
Adjustable link for kinematic mounting systems
Hale, L.C.
1997-07-01
An adjustable link for kinematic mounting systems is disclosed. 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. 3 figs.
Uncertainty quantification in kinematic wave models
Wang, Peng; Tartakovsky, Daniel M.
2012-10-01
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.
Unraveling L_{n,k}: Grassmannian Kinematics
Kaplan, Jared; /SLAC
2010-02-15
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.
NASA Astrophysics Data System (ADS)
Mehanee, Salah Abdelraheem
A new approach for multisource three-dimensional (3-D) finite-difference (FD) electromagnetic (EM) modeling in the frequency domain is introduced. This approach is based on the balance method, solves for the anomalous electric field and automatically takes into account the conservation law of Maxwell's equations. Also a new Dirichlet boundary condition, based on the quasi-analytical (QA) approximation/series, is proposed to truncate the FD modeling grid significantly without notable loss of computational accuracy. The developed 3-D FD modeling code can be used in different geophysical applications including magnetotelluric (MT), controlled source magnetotelluric (CSMT), airborne, and borehole EM methods in the frequency domain. The modeling results obtained by the new algorithm demonstrated good agreement with the respective integral equation solutions. Regularization methods search for a smooth or focused class of the geoelectrical models to invert for. The traditional approach has been to use smooth models to describe the conductivity distribution in the subsurface formations. A new method for two-dimensional (2-D) MT focusing inversion is developed. It approximates the conductivity distribution by models with blocky (focused) conductivity structures. The class (smooth or focused) of inverse models is chosen based on the objective of the survey and available geological information, and can be determined from inversion by selecting the corresponding stabilizing functional in the regularized objective functional subjected to minimization. This new method was applied to synthetic MT data, and MT field data collected for crustal imaging in Carrizo Plain, California and for mining exploration in Voisey's Bay, Canada. A novel algorithm for 3-D EM iterative migration is introduced. It does not require Frechet (Jacobian) matrix computation but rather the conjugate of Frechet matrix acting on the residual field using just one forward modeling run. This algorithm utilizes the 3-D FD method described above and the regularized conjugate gradient (RCG) scheme. In the framework of this approach, the 3-D FD forward modeling solution is computed three times per frequency in each iteration step. In the first forward solution, the FD forward operator is applied to compute the predicted field for a given conductivity distribution. The residual field is then computed by taking the difference between the observed and predicted data. In the second forward solution, the FD operator is utilized to migrate the residual field in the lower half-space using the adjoint operator. In the third forward solution, the FD operator is used to compute the optimal step of minimization. The practical effectiveness of the newly developed 3-D FD inversion technique is illustrated by inverting both synthetic data and field data of Voisey's Bay like geoelectrical model.
Kinematics of Visually-Guided Eye Movements
Hess, Bernhard J. M.; Thomassen, Jakob S.
2014-01-01
One of the hallmarks of an eye movement that follows Listing’s law is the half-angle rule that says that the angular velocity of the eye tilts by half the angle of eccentricity of the line of sight relative to primary eye position. Since all visually-guided eye movements in the regime of far viewing follow Listing’s law (with the head still and upright), the question about its origin is of considerable importance. Here, we provide theoretical and experimental evidence that Listing’s law results from a unique motor strategy that allows minimizing ocular torsion while smoothly tracking objects of interest along any path in visual space. The strategy consists in compounding conventional ocular rotations in meridian planes, that is in horizontal, vertical and oblique directions (which are all torsion-free) with small linear displacements of the eye in the frontal plane. Such compound rotation-displacements of the eye can explain the kinematic paradox that the fixation point may rotate in one plane while the eye rotates in other planes. Its unique signature is the half-angle law in the position domain, which means that the rotation plane of the eye tilts by half-the angle of gaze eccentricity. We show that this law does not readily generalize to the velocity domain of visually-guided eye movements because the angular eye velocity is the sum of two terms, one associated with rotations in meridian planes and one associated with displacements of the eye in the frontal plane. While the first term does not depend on eye position the second term does depend on eye position. We show that compounded rotation - displacements perfectly predict the average smooth kinematics of the eye during steady- state pursuit in both the position and velocity domain. PMID:24751602
Collision kinematics in the western external Alps
NASA Astrophysics Data System (ADS)
Bellahsen, N.; Mouthereau, F.; Boutoux, A.; Bellanger, M.; Lacombe, O.; Jolivet, L.; Rolland, Y.
2014-06-01
The kinematics of the collision in Western Alps are investigated through five balanced cross sections of the whole external domain from the Oisans to the Mont Blanc massif. These cross sections were built using published data for the Jura and subalpine fold-and-thrust belts and new structural and field analysis for the External Crystalline Massifs. Five units are defined: the sedimentary nappes from innermost parts of the external zone (e.g., ultra-Dauphinois/Helvetic), the crystalline units with their dysharmonically folded cover (e.g., Morcles nappe), sedimentary nappes over the frontal parts of the crystalline massifs (the Aravis-Granier unit), the subalpine belts (e.g., Vercors, Chartreuse, Bauges, and Bornes), and the Jura. Except for the ultra-Dauphinois nappes, the shortening, including the cover shortening, always corresponds to basement shortening. The total amount of shortening increases from south (28 km, 20%) to north (66 km, 27%). Moreover, the shortening is slightly older in the south than in the north; deepwater turbidites (flysch) and shallow marine to freshwater clastics (molasse) basins are more developed in the north; pressure and temperature conditions are higher in the north; the average uplift rates are about 3 times higher in the north and more localized in space. We propose that these differences are due to along-strike variations in the structure of the European continental margin inherited from Mesozoic times. We then build five palinspastic maps: one at Cretaceous times showing the inherited European Mesozoic margin structure and four from Priabonian to upper Miocene times showing the collision kinematics and the related rotation of Adria.
INVERSE ANALYSES AND THEIR APPLICATIONS TO NONDESTRUCTIVE EVALUATIONS
Shiro Kubo
2006-01-01
Inverse problems and inverse analyses, which deal with estimation of inputs or source from outputs or results, have been receiving increasing attention in various fields of science and engineering. A reasonable classification of the inverse problems is described. The nature of inverse problems and difficulties encountered in the inverse analyses are discussed. Typical inversion analysis schemes for solving the inverse
Inversion of feedforward neural networks: algorithms and applications
CRAIG A. JENSEN; RUSSELL D. REED; Robert J. Marks II; MOHAMED A. EL-SHARKAWI; Jae-Byung Jung; ROBERT T. MIYAMOTO; GREGORY M. ANDERSON; CHRISTIAN J. EGGEN
1999-01-01
There are many methods for performing neural network inversion. Multi-element evolutionary inversion procedures are capable of finding numerous inversion points simultaneously. Constrained neural network inversion requires that the inversion solution belong to one or more specified constraint sets. In many cases, iterating between the neural network inversion solution and the constraint set can successfully solve constrained inversion problems. This paper
Oracle Inequalities for Inverse Problems
L. Cavalier; G. K. Golubev; D. Picard; A. B. Tsybakov
2002-01-01
We consider a sequence space model of statistical linear inverse problems where we need to estimate a function f from indirect noisy observations. Let a finite set ? of linear estimators be given. Our aim is to mimic the estimator in ? that has the smallest risk on the true f. Under general conditions, we show that this can be
Oracle Inequalities for Inverse Problems
L. Cavalier; G. k. Golubev; D. Picard; A. b. Tsybakov
2000-01-01
We consider a sequence space model of statistical linear inverse problems wherewe need to estimate a function f from indirect noisy observations. Let a finiteset of linear estimators be given. Our aim is to mimic the estimator in thathas the smallest risk on the true f . Under general conditions, we show that thiscan be achieved by simple minimization of
Action understanding as inverse planning
Chris L. Baker; Rebecca Saxe; Joshua B. Tenenbaum
2009-01-01
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
Inverse Problems = Quest for Information
Albert Tarantola; Bernard Valette
1987-01-01
We examine the general non-linear inverse problem with a finite number of parameters. In order to permit the in- corporation of any a priori information about parameters and any distribution of data (not only of gaussian type) we propose to formulate the problem not using single quantities (such as bounds, means, etc.) but using prob- ability density functions for data
INVERSION BASED CONSTRAINED TRAJECTORY OPTIMIZATION
Murray, Richard M.
the Nonlinear Trajectory Generation (NTG) software package. Keywords: Real-time optimization, optimal control and functions are real-analytic. It is desired to find a trajectory of (1), i.e. [t0, tf ] t (x, u)(t) Rn+1INVERSION BASED CONSTRAINED TRAJECTORY OPTIMIZATION Nicolas Petit, Mark B. Milam, Richard M. Murray
Action Understanding as Inverse Planning
ERIC Educational Resources Information Center
Baker, Chris L.; Saxe, Rebecca; Tenenbaum, Joshua B.
2009-01-01
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…
Inverse problem and Bertrand's theorem
Yves Grandati; Alain Bérard; Ferhat Menas
2006-12-03
The Bertrand's theorem can be formulated as the solution of an inverse problem for a classical unidimensional motion. We show that the solutions of these problems, if restricted to a given class, can be obtained by solving a numerical equation. This permit a particulary compact and elegant proof of Bertrand's theorem.
Barrera-Ballesteros, J K; Falcón-Barroso, J; van de Ven, G; Lyubenova, M; Wild, V; Méndez-Abreu, J; Sánchez, S F; Marquez, I; Masegosa, J; Monreal-Ibero, A; Ziegler, B; del Olmo, A; Verdes-Montenegro, L; García-Benito, R; Husemann, B; Mast, D; Kehrig, C; Iglesias-Paramo, J; Marino, R A; Aguerri, J A L; Walcher, C J; Vílchez, J M; Bomans, D J; Cortijo-Ferrero, C; Delgado, R M González; Bland-Hawthorn, J; McIntosh, D H; Bekeraite, Simona
2015-01-01
We present spatially resolved stellar and/or ionized gas kinematic properties for a sample of 103 interacting galaxies, tracing all merger stages: close companions, pairs with morphological signatures of interaction, and coalesced merger remnants. We compare our sample with 80 non-interacting galaxies. We measure for the stellar and the ionized gas components the major (projected) kinematic position angles (PA$_{\\mathrm{kin}}$, approaching and receding) directly from the velocity fields with no assumptions on the internal motions. This method allow us to derive the deviations of the kinematic PAs from a straight line ($\\delta$PA$_{\\mathrm{kin}}$). Around half of the interacting objects show morpho-kinematic PA misalignments that cannot be found in the control sample. Those misalignments are present mostly in galaxies with morphological signatures of interaction. Alignment between the kinematic sides for both samples is similar, with most of the galaxies displaying small misalignments. Radial deviations of the...
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
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.
Generalized inversion and theory of agree
Wu, Hsiao-hung Iris
2008-01-01
In this thesis I examine some of the fundamental questions surrounding inversion structures. I first provide an analysis of Locative Inversion. I show that the mixed A- and A- syntactic behavior of the fronted PP in English ...
Complexity regularization for nonlinear inverse problems
Jean Michel Loubes; Ludeña Carenne
2005-01-01
We provide estimators for a large class of inverse problems, including nonlinear inverse problems. Using complexity regularization technics we provide adaptive estimators achieving the best rate over the collection of models.
The Maximal Kinematical Invariance Group of Fluid Dynamics and Explosion-Implosion Duality
L. O'Raifeartaigh; V. V. Sreedhar
2001-04-09
It has recently been found that supernova explosions can be simulated in the laboratory by implosions induced in a plasma by intense lasers. A theoretical explanation is that the inversion transformation, ($\\Sigma: t \\to -1/t,~ {\\bf x}\\to {\\bf x}/t$), leaves the Euler equations of fluid dynamics, with standard polytropic exponent, invariant. This implies that the kinematical invariance group of the Euler equations is larger than the Galilei group. In this paper we determine, in a systematic manner, the maximal invariance group ${\\cal G}$ of general fluid dynamics and show that it is a semi-direct product ${\\cal G} = SL(2,R) \\wedge G$, where the $SL(2,R)$ group contains the time-translations, dilations and the inversion $\\Sigma$, and $G$ is the static (nine-parameter) Galilei group. A subtle aspect of the inclusion of viscosity fields is discussed and it is shown that the Navier-Stokes assumption of constant viscosity breaks the $SL(2, R)$ group to a two-parameter group of time translations and dilations in a tensorial way. The 12-parameter group ${\\cal G}$ is also known to be the maximal invariance group of the free Schr\\"odinger equation. It originates in the free Hamilton-Jacobi equation which is central to both fluid dynamics and the Schr\\"odinger equation.
Predicting Object Size from Hand Kinematics: A Temporal Perspective
Ansuini, Caterina; Cavallo, Andrea; Koul, Atesh; Jacono, Marco; Yang, Yuan; Becchio, Cristina
2015-01-01
Research on reach-to-grasp movements generally concentrates on kinematics values that are expression of maxima, in particular the maximum aperture of the hand and the peak of wrist velocity. These parameters provide a snapshot description of movement kinematics at a specific time point during reach, i.e., the maximum within a set of value, but do not allow to investigate how hand kinematics gradually conform to target properties. The present study was designed to extend the characterization of object size effects to the temporal domain. Thus, we computed the wrist velocity and the grip aperture throughout reach-to-grasp movements aimed at large versus small objects. To provide a deeper understanding of how joint movements varied over time, we also considered the time course of finger motion relative to hand motion. Results revealed that movement parameters evolved in parallel but at different rates in relation to object size. Furthermore, a classification analysis performed using a Support Vector Machine (SVM) approach showed that kinematic features taken as a group predicted the correct target size well before contact with the object. Interestingly, some kinematics features exhibited a higher ability to discriminate the target size than others did. These findings reinforce our knowledge about the relationship between kinematics and object properties and shed new light on the quantity and quality of information available in the kinematics of a reach-to-grasp movement over time. This might have important implications for our understanding of the action-perception coupling mechanism. PMID:25781473
Analysis of nonlinear channel friction inverse problem
Weiping Cheng; Guohua Liu
2007-01-01
Based on the Backus-Gilbert inverse theory, the singular value decomposition (SVD) for general inverse matrices and the optimization\\u000a algorithm are used to solve the channel friction inverse problem. The resolution and covariance friction inverse model in\\u000a matrix form is developed to examine the reliability of solutions. Theoretical analyses demonstrate that the convergence rate\\u000a of the general Newton optimization algorithm is
Onset of collectivity in neutron-rich Fe isotopes: Toward a new island of inversion?
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
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.
Notes 03. Kinematics of motion in cylindrical journal bearings
San Andres, Luis
2009-01-01
NOTES 3. KINEMATICS OF JOURNAL BEARINGS ? Dr. Luis San Andr?s (2009) 1 NOTES 3 KINEMATICS OF JOURNAL BEARINGS Lecture 3 introduces the analysis of fluid flow in a (simple & ideal) cylindrical journal bearing whose film thickness is a... Y X e e? ?? ?? ? . Journal attitude angle ? Fluid density [kg/m3] ? Fluid absolute viscosity [N.s/m2] ? Whirl frequency [rad/s] ? Journal angular speed [rad/s] NOTES 3. KINEMATICS OF JOURNAL BEARINGS ? Dr. Luis San Andr?s (2009) 2...
Nonlinear Solution of Linear Inverse Problems by
Donoho, David
of homogeneous type { such as numerical dierentiation, inversion of Abel-type transforms, certain convolution is a lineartransformation, such as Radon transform, Convolution transform, or Abel Transform. Such Linear Inverse ProblemsNonlinear Solution of Linear Inverse Problems by Wavelet-Vaguelette Decomposition David L. Donoho
Mathematical Modeling and Analysis Abel inversion using
Kurien, Susan
Mathematical Modeling and Analysis Abel inversion using total-variation regularization Thomas J's density is given by the inverse Abel trans- form of the attenuation measured by the radio- graph. Unfortunately, this approach is of limited use- fulness. The reason is that the inverse Abel trans- form
Radon Transform Inversion using the Shearlet Representation
Labate, Demetrio
Radon Transform Inversion using the Shearlet Representation Flavia Colonna Department The inversion of the Radon transform is a classical ill-posed inverse problem where some method-optimal rate of convergence in estimating a large class of images from noisy Radon data. This is achieved
Inversion of Magnetic Resonance Sounding data
U. Yaramanci; M. Hertrich; Hochschule Zürich
2007-01-01
In this paper the basics, state of the art, current and future developments considering inversion of Magnetic Resonance Sounding (MRS) data are presented. A very brief account is given about the MRS method as such to an extent for better understanding of inversion and what it relates to. The inversion is introduced in general terms as usual for the geophysical
Displacement rank of the Drazin inverse
NASA Astrophysics Data System (ADS)
Diao, Huaian; Wei, Yimin; Qiao, Sanzheng
2004-05-01
In this paper, we study the displacement rank of the Drazin inverse. Both Sylvester displacement and the generalized displacement are discussed. We present upper bounds for the ranks of the displacements of the Drazin inverse. The general results are applied to the group inverse of a structured matrix such as close-to-Toeplitz, generalized Cauchy, Toeplitz-plus-Hankel, and Bezoutians.
Mesospheric temperature inversion and gravity wave breaking
A. Hauchecorne; M. L. Chanin; R. Wilson
1987-01-01
Rayleigh lidar observations of mesospheric temperature over southern France have shown that a temperature inversion is often present which persists for several days at the same altitude. The statistical characteristics of this inversion were determined from more than 500 nightly mean profiles. The characteristics of the inversion are compared with estimates of the amplitude growth with height of a gravity
The role of nonlinearity in inverse problems
Roel Snieder
1998-01-01
In many practical inverse problems, one aims to retrieve a model that has infinitely many degrees of freedom from a finite amount of data. It follows from a simple variable count that this cannot be done in a unique way. Therefore, inversion entails more than estimating a model: any inversion is not complete without a description of the class of
Wavelet Decomposition Approaches to Statistical Inverse Problems
Abramovich, Felix
for such inverse problems do not perform satis- factorily when is spatially inhomogeneous. One existing nonlinear inverse problem for the problem of estimating from noisy data in the model (1). Many such problems fallWavelet Decomposition Approaches to Statistical Inverse Problems BY F. ABRAMOVICH Department
COURSE SYLLABUS GEO 7600 Inverse Theory
Lowry, Anthony R.
). #12;(VERY) TENTATIVE SCHEDULE Date Topic 26 Aug Intro to Inverse Problems: How the model defines) 11 Nov Constrained Optimization (Nonlinear Problems) 13 Nov Cooperative Inversion 18 Nov quantitative observations to an optimally parameterized model. Historically, inversion has been most heavily
Recombination rate predicts inversion size in Diptera.
Cáceres, M; Barbadilla, A; Ruiz, A
1999-01-01
Most species of the Drosophila genus and other Diptera are polymorphic for paracentric inversions. A common observation is that successful inversions are of intermediate size. We test here the hypothesis that the selected property is the recombination length of inversions, not their physical length. If so, physical length of successful inversions should be negatively correlated with recombination rate across species. This prediction was tested by a comprehensive statistical analysis of inversion size and recombination map length in 12 Diptera species for which appropriate data are available. We found that (1) there is a wide variation in recombination map length among species; (2) physical length of successful inversions varies greatly among species and is inversely correlated with the species recombination map length; and (3) neither the among-species variation in inversion length nor the correlation are observed in unsuccessful inversions. The clear differences between successful and unsuccessful inversions point to natural selection as the most likely explanation for our results. Presumably the selective advantage of an inversion increases with its length, but so does its detrimental effect on fertility due to double crossovers. Our analysis provides the strongest and most extensive evidence in favor of the notion that the adaptive value of inversions stems from their effect on recombination. PMID:10471710
Li, Yangmin
problems are solved in closed-form, but also the Jacobian matrix is derived analytically, along, a medical robot applicable to chest compressions is highly required. In this paper, we propose the concept such as high speed, high accuracy, high stiffness, and high load Fig. 1. A schematic of CPR operation. carrying
Novel approach to Abel inversion
Paul, R. K. [Department of Applied Physics, Birla Institute of Technology, Mesra, Ranchi 835215 (India)
2007-09-15
Simple yet versatile, physically valid emissivity functions for peaked and hollow profiles with only two determinable parameters are proposed for performing Abel inversion. The advantages of the proposed functions have been explored. The inversion is very fast, accurate, convenient, and viable, in contrast to the existing methods. The validation of these functions has been confirmed by using simulated data under various conditions. The error in the process has been computed and found to depend on the functional form of the model emissivity. A comprehensive comparison has been drawn with the existing method and it has been found to offer a definite advantage over the existing technique in some respects, especially for real time applications. Limitation of this technique has also been discussed. The soft x-ray and visible light emissivity profile of SINP tokamak has been successfully obtained by using this method.
Novel approach to Abel inversion.
Paul, R K
2007-09-01
Simple yet versatile, physically valid emissivity functions for peaked and hollow profiles with only two determinable parameters are proposed for performing Abel inversion. The advantages of the proposed functions have been explored. The inversion is very fast, accurate, convenient, and viable, in contrast to the existing methods. The validation of these functions has been confirmed by using simulated data under various conditions. The error in the process has been computed and found to depend on the functional form of the model emissivity. A comprehensive comparison has been drawn with the existing method and it has been found to offer a definite advantage over the existing technique in some respects, especially for real time applications. Limitation of this technique has also been discussed. The soft x-ray and visible light emissivity profile of SINP tokamak has been successfully obtained by using this method. PMID:17902949
Inverse Compton conversion. Final report
Weitz, R.L. [Science Applications International Corp., Albuquerque, NM (United States)
1990-11-19
Inverse Compton conversion has been proposed as an alternative to the bremsstrahlung conversion process as a method of transforming the kinetic energy of an electron beam into a directed beam of photons. An electron beam with incident electron kinetic energy E{sub o} enters a volume of dimension L containing a photon gas, which is characterized by a blackbody temperature E{sub bb} and a density {rho}{sub {gamma}}. The electrons will inverse-Compton scatter with individual photons in the photon gas. In this process, energy is transferred to the photons, which are then emitted in the forward direction. The resultant photon beam could be used to deliver a radiation dose to a distant target. This report discusses the theoretical formulation of the problem, presents sample results, and describes the computer code developed to analyze this concept.
Techniques in Doppler gravity inversion
NASA Technical Reports Server (NTRS)
Phillips, R. J.
1974-01-01
The types of Doppler gravity data available for local as opposed to planetwide geophysical modeling are reviewed. Those gravity fields that are determined dynamically in orbit determination programs yield a smoothed representation of the local gravity field that may be used for quantitative modeling. An estimate of the difference between smoothed and true fields can be considered as a noise limitation in generating local gravity models. A nonlinear inversion for the geometry, depth, and density of the Mare Serenitatis mascon using an ellipsoidal model yielded a global least squares minimum in horizontal dimensions, depth, and thickness-density contrast product. It was subsequently found, by using a linear model, that there were an infinite number of solutions corresponding to various combinations of depth and lateral inhomogeneity. Linear modeling was performed by means of generalized inverse theory.
Kinematic analysis of rope skipper's stability
NASA Astrophysics Data System (ADS)
Ab Ghani, Nor Atikah; Rambely, Azmin Sham
2014-06-01
There are various kinds of jumping that can be done while performing rope skipping activity. This activity was always associated with injury. But, if the rope skipper can perform the activity in a right way, it is believed that the injury might be reduced. The main purpose of this paper is to observe the stability of rope skipper from a biomechanics perspective, which are the centre of mass, angle at the ankle, knee and hip joints and also the trajectory for the ipsilateral leg between the two types of skip which is one leg and two legs. Six healthy, physically active subject, two males and four females (age: 8.00±1.25 years, weight: 17.90±6.85 kg and height: 1.22±0.08 m) participated in this study. Kinematic data of repeated five cycles of rope skipping activity was captured by using Vicon Nexus system. Based on the data collected, skipping with two legs shows more stable behavior during preparation, flight and landing phases. It is concluded that landing on the balls of the feet, lowering the trajectory positions of the feet from the ground as well as flexion of each joint which would reduce the injury while landing.
Feeding underground: kinematics of feeding in caecilians.
Herrel, Anthony; Measey, G John
2012-11-01
Caecilians are limbless amphibians that have evolved distinct cranial and postcranial specializations associated with a burrowing lifestyle. Observations on feeding behavior are rare and restricted to above-ground feeding in laboratory conditions. Here we report data on feeding in tunnels using both external video and X-ray recordings of caecilians feeding on invertebrate prey. Our data show feeding kinematics similar to those previously reported, including the pronounced neck bending observed during above-ground feeding. Our data illustrate, however, that caecilians may be much faster than previously suspected, with lunge speeds of up to 7 cm?sec(-1). Although gape cycles are often slow (0.67?±?0.29 sec), rapid jaw closure is observed during prey capture, with cycle times and jaw movement velocities similar to those observed in other terrestrial tetrapods. Finally, our data suggest that gape angles may be large (64.8?±?18°) and that gape profiles are variable, often lacking distinct slow and fast opening and closing phases. These data illustrate the importance of recording naturalistic feeding behavior and shed light on how these animals are capable of capturing and processing prey in constrained underground environments. Additional data on species with divergent cranial morphologies would be needed to better understand the co-evolution between feeding, burrowing, and cranial design in caecilians. PMID:22927194
Thermally Insulating, Kinematic Tensioned-Fiber Suspension
NASA Technical Reports Server (NTRS)
Voellmer, George M.
2004-01-01
A salt pill and some parts of a thermally insulating, kinematic suspension system that holds the salt pill rigidly in an adiabatic-demagnetization refrigerator (ADR) is presented. "Salt pill" in this context denotes a unit comprising a cylindrical container, a matrix of gold wires in the container, and a cylinder of ferric ammonium alum (a paramagnetic salt) that has been deposited on the wires. The structural members used in this system for both thermal insulation and positioning are aromatic polyamide fibers (Kevlar(R) or equivalent) under tension. This suspension system is designed to satisfy several special requirements to ensure the proper operation of the ADR. These requirements are to (1) maintain the salt pill at a specified position within the cylindrical bore of an electromagnet; (2) prevent vibrations, which would cause dissipation of heat in the salt pill; and (3) minimize the conduction of heat from the electromagnet bore and other neighboring objects to the salt pill; all while (4) protecting the salt pill (which is fragile) against all tensile and bending loads other than those attributable to its own weight. In addition, the system is required to consist of two subsystems -- one for the top end and one for the bottom end of the salt pill -- that can be assembled and tensioned separately from each other and from the salt pill, then later attached to the salt pill.
Kinematic mental simulations in abduction and deduction
Khemlani, Sangeet Suresh; Mackiewicz, Robert; Bucciarelli, Monica; Johnson-Laird, Philip N.
2013-01-01
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
Kinematics of kiloparsec-scale jets
NASA Astrophysics Data System (ADS)
Laing, R. A.; Bridle, A. H.
2015-03-01
It has long been known that kiloparsec-scale jets in radio galaxies can be divided into two flavours: strong (found in powerful sources, narrow and terminating in compact hot-spots) and weak (found in low-luminosity sources, flaring, unable to form hot-spots and terminating in diffuse lobes or tails). Both flavours are initially relativistic, but weak jets decelerate to sub-relativistic, transonic speeds by entraining external gas while strong jets remain relativistic and supersonic until they terminate. Much is now known about the kinematics of weak-flavour jets, which can be modelled as intrinsically symmetrical, decelerating relativistic flows, and we summarize the results of our work in this area. Strong-flavour jets are relatively faint and narrow, so it has hitherto proved difficult to obtain the necessary deep, transverse-resolved images in total intensity and linear polarization. The spectacular jets in the radio galaxy NGC 6251 appear to represent a transition case between weak and strong flavours: the jets show no clear evidence for deceleration, but are relatively wide. VLA observations hint at transverse velocity structure with a very fast (Lorentz factor >5) spine surrounded by a slower shear layer. New observations with the upgraded VLA should be able to test this picture.
The [N II] Kinematics of R Aquarii
NASA Technical Reports Server (NTRS)
Hollis, J. M.; Vogel, S. N.; VanBuren, D.; Strong, J. P.; Lyon, R. G.; Dorband, J. E.
1998-01-01
We report a kinematic study of the symbiotic star system R Aqr derived from [N H]lambda 6584 emission observations with a Fabry-Perot imaging spectrometer. The [N II] spatial structure of the R Aqr jet, first observed circa 1977, and surrounding hourglass-shaped nebulosity, due to an explosion approximately 660 years ago, are derived from 41 velocity planes spaced at approximately 12 km/s intervals. Fabry-Perot imagery shows the elliptical nebulosity comprising the waist of the hourglass shell is consistent with a circular ring expanding radially at 55 km/s as seen at an inclination angle, i approximately 70 deg. Fabry-Perot imagery shows the two-sided R Aqr jet is collimated flow in opposite directions. The intensity-velocity structure of the strong NE jet component is shown in contrast to the amorphous SW jet component. We offer a idealized schematic model for the R Aqr jet motion which results in a small-scale helical structure forming around a larger-scale helical path. The implications of such a jet model are discussed. We present a movie showing a side-by-side comparison of the spatial structure of the model and the data as a function of the 41 velocity planes.
Bat flight: aerodynamics, kinematics and flight morphology.
Hedenström, Anders; Johansson, L Christoffer
2015-03-01
Bats evolved the ability of powered flight more than 50 million years ago. The modern bat is an efficient flyer and recent research on bat flight has revealed many intriguing facts. By using particle image velocimetry to visualize wake vortices, both the magnitude and time-history of aerodynamic forces can be estimated. At most speeds the downstroke generates both lift and thrust, whereas the function of the upstroke changes with forward flight speed. At hovering and slow speed bats use a leading edge vortex to enhance the lift beyond that allowed by steady aerodynamics and an inverted wing during the upstroke to further aid weight support. The bat wing and its skeleton exhibit many features and control mechanisms that are presumed to improve flight performance. Whereas bats appear aerodynamically less efficient than birds when it comes to cruising flight, they have the edge over birds when it comes to manoeuvring. There is a direct relationship between kinematics and the aerodynamic performance, but there is still a lack of knowledge about how (and if) the bat controls the movements and shape (planform and camber) of the wing. Considering the relatively few bat species whose aerodynamic tracks have been characterized, there is scope for new discoveries and a need to study species representing more extreme positions in the bat morphospace. PMID:25740899
GLOBAL H I KINEMATICS IN DWARF GALAXIES
Stilp, Adrienne M.; Dalcanton, Julianne J. [Department of Astronomy, University of Washington, Box 351580, Seattle, WA 98195 (United States); Warren, Steven R.; Skillman, Evan [Minnesota Institute for Astrophysics, University of Minnesota, 116 Church St. SE, Minneapolis, MN 55455 (United States); Ott, Juergen [National Radio Astronomy Observatory, P.O. Box O, 1003 Lopezville Road, Socorro, NM 87801 (United States); Koribalski, Baerbel [Australia Telescope National Facility, CSIRO Astronomy and Space Science, P.O. Box 76, Epping, NSW 1710 (Australia)
2013-03-10
H I line widths are typically interpreted as a measure of interstellar medium turbulence, which is potentially driven by star formation (SF). In an effort to better understand the possible connections between line widths and SF, we have characterized H I kinematics in a sample of nearby dwarf galaxies by co-adding line-of-sight spectra after removing the rotational velocity to produce average global H I line profiles. These ''superprofiles'' are composed of a central narrow peak ({approx}6-10 km s{sup -1}) with higher-velocity wings to either side that contain {approx}10%-15% of the total flux. The superprofiles are all very similar, indicating a universal global H I profile for dwarf galaxies. We compare characteristics of the superprofiles to various galaxy properties, such as mass and measures of SF, with the assumption that the superprofile represents a turbulent peak with energetic wings to either side. We use these quantities to derive average scale heights for the sample galaxies. When comparing to physical properties, we find that the velocity dispersion of the central peak is correlated with ({Sigma}{sub HI}). The fraction of mass and characteristic velocity of the high-velocity wings are correlated with measures of SF, consistent with the picture that SF drives surrounding H I to higher velocities. While gravitational instabilities provide too little energy, the SF in the sample galaxies does provide enough energy through supernovae, with realistic estimates of the coupling efficiency, to produce the observed superprofiles.
The Kinematic State of the Local Volume
Alan B. Whiting
2003-02-06
The kinematics of galaxies with 10 megaparsecs (10 Mpc) of the Milky Way is investigated using published distances and radial velocities. With respect to the average Hubble flow (isotropic or simple anisotropic), there is NO systematic relation between peculiar velocity dispersion and absolute magnitude over a range of 10 magnitudes; neither is there any apparent variation with galaxy type or between field and cluster members. There are several possible explanations for the lack of variation, though all have difficulties: either there is no relationship between light and mass on these scales, or the peculiar velocities are not produced by gravitational interaction, or the background dynamical picture is wrong in some systematic way. The extremely cold local flow of 40-60 km/s dispersion reported by some authors is shown to be an artifact of sparse data, a velocity dispersion of over 100 km/s being closer to the actual value. Galaxies with a high (positive) radial velocity have been selected against in studies of this volume, biasing numerical results.
A kinematic wave theory of capacity drop
Wen-Long Jin; Qi-Jian Gan; Jean-Patrick Lebacque
2013-10-09
Capacity drop at active bottlenecks is one of the most puzzling traffic phenomena, but a thorough understanding is practically important for designing variable speed limit and ramp metering strategies. In this study, we attempt to develop a simple model of capacity drop within the framework of kinematic wave theory based on the observation that capacity drop occurs when an upstream queue forms at an active bottleneck. In addition, we assume that the fundamental diagrams are continuous in steady states. This assumption is consistent with observations and can avoid unrealistic infinite characteristic wave speeds in discontinuous fundamental diagrams. A core component of the new model is an entropy condition defined by a discontinuous boundary flux function. For a lane-drop area, we demonstrate that the model is well-defined, and its Riemann problem can be uniquely solved. We theoretically discuss traffic stability with this model subject to perturbations in density, upstream demand, and downstream supply. We clarify that discontinuous flow-density relations, or so-called "discontinuous" fundamental diagrams, are caused by incomplete observations of traffic states. Theoretical results are consistent with observations in the literature and are verified by numerical simulations and empirical observations. We finally discuss potential applications and future studies.
Dielectric screening in inversion layers
G. Srinivasan; M. Jonson
1975-01-01
The authors have investigated the dielectric response of carriers in inversion layers in a MISFET. Particular attention has been paid to the Anderson-localized regime (where the carriers are localized by disorder) and the possible Wigner lattice. In the Anderson-localized regime, it is found that the long-wavelength dielectric function is given by a Thomas-Fermi function. The most interesting feature of the
Statistical Inference in Inverse Problems
Xun, Xiaolei
2012-07-16
fields, from science like physics and biology to engineering like medical imaging and remote sensing. Generally speaking, inverse problems are concerned with converting observed measurements into informa- tion about quantities of a physical system... The biases, standard deviations (SDs), square root of mean squared errors (RMSEs) of the parameter estimates for the PDE model (3.2) using the Bayesian method (BM), the parameter cascading method (PC), and the two-stage method (TS) in the 1000 sim...
Inversion of potential field data
P. S. Moharir
1990-01-01
The problem of inversion of potential field data is a challenging one because of the difficulty in obtaining a unique solution.\\u000a This paper identifies various types of nonuniqueness and argues that it is neither possible nor necessary to remove all categories\\u000a of nonuniqueness. Some types of nonuniqueness are due to human limitations and choice and these would always persist.\\u000a \\u000a Listing
Inverse Relationships (Multiplication and Division)
NSDL National Science Digital Library
2012-07-13
This activity for the interactive white board (free access with registration) provides an opportunity for learners to practice building the fact family sets to reinforce the inverse relationship between multiplication and division. A set of three numbers are displayed and the learner drags the numbers and the operation down into the spaces to create a number fact (equation). The goal is to find all four facts in the family.
Linear and Nonlinear Inverse Problems
Roel Snieder; Jeannot Trampert
2000-01-01
An important aspect of the physical sciences is to make inferences about physical paramcters from data. In general, the laws\\u000a of physics provide the means for computing the data values given a model. This is called the “forward problem”, see figure\\u000a 1. In the inverse problem, the aim is to reconstruct the model from a set of measurements. In the
Lightcurve Inversion for 65 Cybele
NASA Astrophysics Data System (ADS)
Franco, Lorenzo; Pilcher, Frederick
2015-07-01
We present a shape and spin axis model for main-belt asteroid 65 Cybele. The model was obtained with lightcurve inversion process, using combined dense photometric data obtained during fifteen apparitions from 1977 to 2014 and sparse data from USNO Flagstaff. Analysis of the resulting data found a sidereal period P = 6.081434 ± 0.000005 hours and two possible pole solutions: (l = 208°, b = –7°) and (l = 27°, b = –14°) with an error of ±15 degrees.
Theory of lasers without inversion
Blok, V.R.; Krochik, G.M. (Applied Science Research Laboratory, 106-3C Twin Willow Court, Owings Mills, Maryland 21117-2729 (US))
1990-02-01
We here present the theory of lasing without inversion for systems with a split upper laser level. We show that the effect of amplification without inversion may be realized for at least two different situations. In the first situation, the effect is due to the asymmetry of radiative characteristics of quasidegenerate transitions. In the second situation, the effect can be provided without any asymmetry and is achievable for the definite phase of the transfer of coherence between the quasidegenerate levels (quasiparametric amplification). We also show that for laser amplification without inversion, the rate (frequency) of mixing of the quasidegenerate levels should be significantly higher than the linewidths of these levels. This mixing of quasidegenerate levels can be realized by low-frequency electromagnetic radiation or by interaction with an auxiliary third level. In addition, we derive the conditions for providing laser action for such systems rigorously, and we give some specific examples for the realization of this effect in gaseous and solid-state media. One of the most promising configurations may be realized in solid-state media when two narrow quasidegenerate levels are embedded in quasifree states (low-density state conduction band). We also discuss the use of a parametric mechanism for the creation of spatial gratings and for the construction of new types of electro-optical devices.
The Inverse Electromagnetic Scattering Problem for Anisotropic Media
Cakoni, Fioralba
The Inverse Electromagnetic Scattering Problem for Anisotropic Media Fioralba Cakoni1 , David. The inverse electromagnetic scattering problem for anisotropic media plays a special role in inverse. Introduction The inverse electromagnetic scattering problem for anisotropic media plays a special role
A kinematic coupling based 6 degrees of freedom dynamometer
Moreu Gamazo, Jaime
2009-01-01
A new 6-degree of freedom dynamometer is presented. Six load cells measure the normal forces at the contact points of a three groove kinematic coupling. Three toggle clamps are used to preload the machine, so that it does ...
Kinematic wave model of bed profiles in alluvial channels
Tayfur, Gokmen; Singh, Vijay P.
2006-06-21
A mathematical model, based on the kinematic wave (KW) theory, is developed for describing the evolution and movement of bed profiles in alluvial channels. The model employs a functional relation between sediment transport rate and concentration, a...
Theoretical Positioning Accuracy for Serial and Parallel Kinematic Structure
NASA Astrophysics Data System (ADS)
Kurekova, Eva; Halaj, Martin; Omachelová, Milada; Martišovitš, Ilja
2014-10-01
Modern production machines employ complex kinematic structures that shall enhance their performance. As those machines are very sophisticated electro-mechanical structures, their design is time consuming and financially demanding. Therefore, designers search for new possibilities how to estimate future properties of the machine as early as in the design phase. The paper gives a brief introduction to the adoption of methodology of measurement uncertainties into the design of production machines. The adapted methodology enables to estimate the theoretical positioning accuracy of the machine end effector that is one of the important indicators of machine performance. Both serial and parallel kinematic structures are considered in the paper. Methodology and sample calculations of theoretical positioning accuracy are presented for serial kinematic structure (represented by advanced plasma cutting head) and parallel kinematic structure, represented by one specific design named Tricept.
Kinematic distributions for electron pair production by muons
NASA Technical Reports Server (NTRS)
Linsker, R.
1972-01-01
Cross sections and kinematic distributions for the trident production process plus or negative muon plus charge yields plus or minus muon plus electron plus positron plus charge (with charge = dipion moment and Fe) are given for beam energies of 100 to 300 GeV at fixed (electron positron) masses from 5 to 15 GeV. This process is interesting as a test of quantum electrodynamics at high energies, and in particular as a test of the form of the photon propagator at large timelike (four-momentum) squared. For this purpose, it is desirable to impose kinematic cuts that favor those Bethe-Heitler graphs which contain a timelike photon propagator. It is found that there are substantial differences between the kinematic distributions for the full Bethe-Heitler matrix element and the distributions for the two timelike-photon graphs alone; these differences can be exploited in the selection of appropriate kinematic cuts.
3D kinematics of white dwarfs from the SPY project
E. -M. Pauli; R. Napiwotzki; M. Altmann; U. Heber; M. Odenkirchen; F. Kerber
2003-01-23
We present kinematics of a sample of 107 DA white dwarfs from the SPY project and discuss kinematic criteria for a distinction of thin disk, thick disk, and halo populations. This is the first homogeneous sample of white dwarfs for which 3D space motions have been determined. Studies of white dwarf kinematics can help determine the fraction of the total mass of our Galaxy contained in the form of thick disk and halo white dwarfs. Radial velocities and spectroscopic distances obtained by the SPY project are combined with our measurements of proper motions to derive 3D space motions. Galactic orbits and further kinematic parameters are computed. Candidates for thick disk and halo members are selected in a first step from the classical U-V-velocity diagram. Our final assignment of population membership is based on orbits and position in the angular-momentum-eccentricity diagram. We find four halo and twelve thick disk white dwarfs.
Kinematics and amplitude evolution of global coronal extreme ultraviolet waves
Ting Li; Jun Zhang; Shu-Hong Yang; Wei Liu
2012-01-01
With the observations of the Solar-Terrestrial Relations Observatory (STEREO) and the Solar Dynamics Observatory (SDO), we analyze in detail the kinematics of global coronal waves together with their intensity amplitudes (so-called “perturbation profiles\\
STAR CLUSTERS IN M31: OLD CLUSTERS WITH BAR KINEMATICS
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
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.
PERIORAL BIOMECHANICS, KINEMATICS, AND ELECTROPHYSIOLOGY IN PARKINSON'S DISEASE
Chu, Shin Ying
2010-11-21
This investigation quantitatively characterized the orofacial biomechanics, labial kinematics, and associated electromyography (EMG) patterns in individuals with Parkinson's disease (PD) as a function of anti-PD medication state. Passive perioral...
Influence of the 3D inverse dynamic method on the joint forces and moments during gait.
Dumas, R; Nicol, E; Chèze, L
2007-10-01
The joint forces and moments are commonly used in gait analysis. They can be computed by four different 3D inverse dynamic methods proposed in the literature, either based on vectors and Euler angles, wrenches and quaternions, homogeneous matrices, or generalized coordinates and forces. In order to analyze the influence of the inverse dynamic method, the joint forces and moments were computed during gait on nine healthy subjects. A ratio was computed between the relative dispersions (due to the method) and the absolute amplitudes of the gait curves. The influence of the inverse dynamic method was negligible at the ankle (2%) but major at the knee and the hip joints (40%). This influence seems to be due to the dynamic computation rather than the kinematic computation. Compared to the influence of the joint center location, the body segment inertial parameter estimation, and more, the influence of the inverse dynamic method is at least of equivalent importance. This point should be confirmed with other subjects, possibly pathologic, and other movements. PMID:17887905
Contemporary kinematics of the southern Aegean and the Mediterranean Ridge
Corné Kreemer; Nicolas Chamot-Rooke
2004-01-01
This study focuses on the kinematics of the southern Aegean and the Mediterranean Ridge (MR). A quantification of the deformation of the MR is essential for both evaluating physical models of accretionary wedges in general and for obtaining a self-consistent model of the surface deformation over the entire Nubia-Eurasia (NU-EU) plate boundary zone in the eastern Mediterranean. Previous kinematic studies
Collinearity approximations and kinematic shifts in partonic shower algorithms
F. Hautmann; H. Jung
2012-09-28
We study kinematic effects due to the approximation of on-shell, collinear partons in shower Monte Carlo event generators. We observe that the collinearity approximation, combined with the requirements of energy-momentum conservation, gives rise to a kinematic shift, event by event, in longitudinal momentum distributions. We present numerical results in the case of jet and heavy flavor production processes measured at the LHC.
Specimen-specific method for quantifying glenohumeral joint kinematics.
Lee, Yeon Soo; Lee, Thay Q
2010-10-01
The existing glenohumeral joint kinematic protocols are highly effective for studying in vivo shoulder kinematics but are not anatomically specific enough to address the asymmetric changes in glenohumeral joint kinematics and do not provide clear anatomic definitions for landmarks and directions. Therefore, the objective of this study was to develop an anatomically relevant and specimen-specific three-dimensional glenohumeral joint kinematic method as a new standard definition protocol for the glenohumeral coordinate systems (CSs). The in situ kinematic data of the intra-capsular glenoid-based CS of the glenohumeral joint were mathematically determined from the kinematic data of the extra-capsular CSs measured with an intact capsule. To minimize irreproducibility arising from discrepancy in initial specimen condition and error in determining CSs, several techniques were employed to determine anatomical landmarks and directions. To examine and demonstrate the details of this method, six fresh frozen cadaveric shoulders were used with a custom shoulder testing system. The accuracy and repeatability in the humeral head center (HHC) measurement were 0.44 and 0.41 mm, respectively. The inter-observer reliability for the location of the glenoid CS origin and HHC were 0.37 and 0.30 mm, respectively. The smaller anteroposterior (AP) depth of the glenoid with respect to the superoinferior (SI) depth (27.3 ± 16.5%) was significantly correlated to the larger AP/SI translation ratio of the humeral head apex (191.4 ± 43.8%, R = 0.90, p = 0.02). This study provides a glenohumeral kinematic protocol that enables the assessment of asymmetric glenohumeral kinematics determined by a precise and reproducible method using anatomic landmarks. PMID:20499181
Kinematic Precise Orbit Determination for Gravity Field Determination
D. Švehla; M. Rothacher
In this paper we first present approaches and results in precise orbit determination (POD) for satellites in Low Earth Orbit\\u000a (LEO) based on one or two frequency GPS measurements and, secondly, we focus on the relations between kinematic POD and gravity\\u000a field determination. Using GPS measurements of the CHAMP satellite we show that it is possible to estimate kinematic positions
Interplanetary stream magnetism: Kinematic effects. [solar magnetic fields and wind
NASA Technical Reports Server (NTRS)
Burlaga, L. F.; Barouch, E.
1974-01-01
The particle density, and the magnetic field intensity and direction are calculated in corotating streams of the solar wind, assuming that the solar wind velocity is constant and radial and that its azimuthal variations are not two rapid. The effects of the radial velocity profile in corotating streams on the magnetic fields were examined using kinematic approximation and a variety of field configurations on the inner boundary. Kinematic and dynamic effects are discussed.
Doriot, Nathalie; Chèze, Laurence
2004-01-01
This paper presents a method to analyze three dimensional kinematics and dynamics of lower limb during walking. The proposed method is based on a homogeneous matrix concept, derived from robotics and using compact, expressive notation convenient for computer applications. The major advantage of this method is that no hypothesis is required on the joint model, which makes it applicable to complex and pathologic joints. Kinematic data are computed from 3-D trajectories of markers collected by a motion analysis system. External forces applied on the leg are measured synchronously during the stance phase of gait. Angular velocity components obtained using the homogeneous matrix method are displayed for three subjects and compared with those obtained from the same experimental data using a helical axis method. Then, intersegmental moments calculated from the inverse dynamic part of the homogeneous matrix method are shown on the same subjects. Kinematic results indicate that there are no significant differences between the methods, thus demonstrating the reproducibility of the stance phase of gait in the sagittal plane. Use of this synthetic homogeneous method developed for both kinematics and dynamics of rigid bodies demonstrates good promise for applications in biomechanics. PMID:14723490