The Experts below are selected from a list of 38550 Experts worldwide ranked by ideXlab platform
Thomas J. Impelluso - One of the best experts on this subject based on the ideXlab platform.
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Modeling friction in robotic systems using the Moving Frame method in dynamics
The International journal of mechanical engineering education, 2019Co-Authors: Thorstein R. Rykkje, Daniel Leinebø, Erlend Sande Bergaas, Andreas Skjelde, Thomas J. ImpellusoAbstract:This paper reports on the new Moving Frame method in dynamics that has proven to excite students and reduce student attrition. It applies the Moving Frame method to the analysis of a two-body syste...
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Modeling Crane-Induced Ship Motion Using the Moving Frame Method
Journal of Offshore Mechanics and Arctic Engineering-transactions of The Asme, 2019Co-Authors: Paulo Alexander Jacobsen Jardim, Thorstein R. Rykkje, Jan Tore Rein, Øystein Haveland, Thomas J. ImpellusoAbstract:A decline in oil-related revenues challenges Norway to focus on new types of offshore installations. Often, ship-mounted crane systems transfer cargo or crew onto offshore installations such as floating windmills. This project analyzes the motion of a ship induced by an onboard crane in operation using a new theoretical approach to dynamics: the Moving Frame method (MFM). The MFM draws upon Lie group theory and Cartan's Moving Frames. This, together with a compact notation from geometrical physics, makes it possible to extract the equations of motion, expeditiously. While others have applied aspects of these mathematical tools, the notation presented here brings these methods together; it is accessible, programmable, and simple. In the MFM, the notation for multibody dynamics and single body dynamics is the same; for two-dimensional (2D) and three-dimensional (3D), the same. Most importantly, this paper presents a restricted variation of the angular velocity to use in Hamilton's principle. This work accounts for the masses and geometry of all components, interactive motor couples and prepares for buoyancy forces and added mass. This research solves the equations numerically using a relatively simple numerical integration scheme. Then, the Cayley–Hamilton theorem and Rodriguez's formula reconstruct the rotation matrix for the ship. Furthermore, this work displays the rotating ship in 3D, viewable on mobile devices. This paper presents the results qualitatively as a 3D simulation. This research demonstrates that the MFM is suitable for the analysis of “smart ships,” as the next step in this work.
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Modeling Stabilization of Crane-Induced Ship Motion With Gyroscopic Control Using the Moving Frame Method
Journal of Computational and Nonlinear Dynamics, 2019Co-Authors: Josef Flatlandsmo, Torbjørn Smith, Ørjan O. Halvorsen, Thomas J. ImpellusoAbstract:This paper presents a new method in multibody dynamics and applies it to the challenge of stabilizing ship motion induced by onboard crane operations. Norwegian industries are constantly assessing new technologies for more efficient and safer production in the aquacultural, renewable energy, and oil and gas industries. They share a common challenge to install new equipment and transfer personnel in a safe and controllable way between ships, fish farms, and oil platforms. This paper deploys the Moving Frame method (MFM) to analyze the motion induced by a crane, yet controlled by a gyroscopic inertial device. We represent the crane as a simple two-link system that transfers produce and equipment to and from barges. We analyze how an inertial flywheel can stabilize the ship during the transfer. Lie group theory and the work of Elie Cartan are the foundations of the MFM. This, together with a restriction on the variation of the angular velocity used in Hamilton's principle, enables an effective way of extracting the equations of motion for an open-loop system. Furthermore, this work displays the results in three-dimensional (3D) on cell phones. The long-term results of this work lead to a robust 3D active compensation method for loading/unloading operations offshore. Finally, the simplicity of the analysis anticipates the impending time of artificial intelligence when machines, equipped with onboard central processing units and internet protocol addresses, are empowered with learning modules to conduct their operations.
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Modelling Subsea ROV Motion Using the Moving Frame Method
Volume 4A: Dynamics Vibration and Control, 2018Co-Authors: Katrine Oen Austefjord, Linn-kristin Skeide Larsen, Martin Oddøy Hestvik, Thomas J. ImpellusoAbstract:Norway conducts operations on a variety of structures in the North Sea; e.g. oilrigs, monopole windmills, subsea trees. These structures often require subsea installation, observation, and maintenance. Research and technology that can improve the efficiency of these operations are of high interest to the nation. A remotely operated vehicle (ROV) can assist in these operations. However, the ROV pilot must observe and adjust the vehicle and its motion in accordance with its task, but modified due to impending forces. Automation of this motion is the desired goal. This paper researches the motion of an ROV induced by the motion of the robotic manipulators, motor torques, and fluid buoyancy. The research introduces a new method in engineering dynamics: the Moving Frame Method (MFM). Lie Group Theory and Cartan’s notion of Moving Frames are the foundation of the MFM. This research extends previous work in significant ways. This research accounts for the motor torques, fluid viscosity and the mass of the manipulator’s arms. Interactive visualization on hand-held devices is also an integral part of this research. The Web Graphics Library (WebGL) is a JavaScript API for rendering interactive 3D and 2D graphics within any compatible web browser without the use of plug-ins. This work visualizes the results, interactively, on 3D web pages, viewable on cell phones using WebGL. This work invites further research into improved numerical methods, solid/fluid interaction and the design of Autonomous Underwater Vehicles (AUV). AUVs beckon an era of Artificial Intelligence when machines think, communicate and learn. Rapidly deployable software implementations will be essential to this task. This paper demonstrates the MFM clears the path toward such technological innovations.
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Modeling Crane Induced Ship Motion Using the Moving Frame Method
Volume 4B: Dynamics Vibration and Control, 2018Co-Authors: Paulo Alexander Jacobsen Jardim, Jan Tore Rein, Øystein Haveland, Thomas J. ImpellusoAbstract:A decline in oil-related revenues challenges Norway to focus on new types of offshore installations and their maintenance. Often, ship-mounted crane systems transfer cargo or crew onto marine structures such as floating windmills. This project analyzes the motion of a ship induced by an onboard crane in operation. It analyzes the motion of a crane mounted on a ship using The Moving Frame Method (MFM). The MFM draws upon Lie group theory and Cartan’s Moving Frames. This, together with a compact notation from geometrical physics, makes it possible to extract the equations of motion, expeditiously. This work extends a previous project that assumed many simplifications. It accounts for the masses and geometry of all components. This current approach also accounts interactive motor couples and prepares for buoyancy forces and added mass. The previous work used a symbolic manipulator, resulting in unwieldy equations. In this current phase, this research solves the equations numerically using a relatively simple numerical integration scheme. Then, the Cayley-Hamilton theorem and Rodriguez’s formula reconstructs the rotation matrix for the ship. Furthermore, this work displays the rotating ship in 3D, viewable on mobile devices. WebGL is a JavaScript API for rendering interactive 3D and 2D graphics within any compatible web browser without the use of plug-ins. This paper presents the results qualitatively as a 3D simulation. This research proves that the MFM is suitable for the analysis of “smart ships,” as the next step in this work.
Imran Khan - One of the best experts on this subject based on the ideXlab platform.
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Combined Time Interval in Moving Frame
2019Co-Authors: Imran KhanAbstract:This paper has been studied the relativity time and a time interval in the Moving Frame, when the time interval in rest fame is zero then will get this time interval in the Moving Frame. Notable that, by combining these two time intervals and in Moving Frames there is another a time interval in the Moving Frame in the Moving Frame. That is to say, there will be combine time interval in the Moving Frame. If there is a distance between the two points and in the rest Frame and the time interval between those two points and , then this combination of time interval will be available in Moving Frames. Here, Relativity time refers to dilated time. The Moving Frame will have a relativity time. Keywords Special relativity, Lorentz transformation, combine time interval, dilated time, time interval, Moving Frame, equilibrium, rest Frame
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The time interval in Moving Frames can be negative
2019Co-Authors: Imran KhanAbstract:With respect two each other in the Moving Frame two time interval between and minus the result will be another time interval in Moving Frame. Therefore In particular case will be, for which the time interval will be negative. Here, is the relativity time, is the rest time interval. This equation is Einstein’s time dilation equation And since, Where, is a time interval in Moving Frame. This time interval can be found in Moving Frame when the time interval is zero in the rest Frame.
Yu-chieng Liou - One of the best experts on this subject based on the ideXlab platform.
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Single-Doppler Retrieval of the Three-Dimensional Wind in a Deep Convective System Based on an Optimal Moving Frame of Reference
Journal of the Meteorological Society of Japan, 2007Co-Authors: Yu-chieng LiouAbstract:A single-Doppler radar velocity retrieval method, based on an optimally determined Moving Frame of reference, is developed. This method enables the recovery of the complete three-dimensional wind field using reflectivity, and radial wind observations, detected by a single Doppler radar over multiple volume scans. This method first computes a set of optimal Moving speeds (U, V, W), which can be functions of the height. It is considered optimal in the sense that when a reference Frame is traveling at this speed, as much of the radar reflectivity, interpolated onto this Frame can be conserved as possible. The perturbation velocities (u′, v′, w′) are then solved simultaneously, with respect to the Moving speeds, by minimizing a cost function through the three-dimensional variational (3D-Var) approach. This cost function consists of a set of weak constraints, mainly the equation for radar reflectivity conservation, the continuity equation, the geometric relationship between the radar-observed radial wind and the Cartesian winds, and a smoothness filter. Finally, by adding the optimal Moving speed to the perturbation velocities, a complete three-dimensional wind field is obtained.The performance of this method is tested under different scenarios, including cases with deep convections, embedded in an environment without mean wind, with constant mean wind, with vertical wind shear of the horizontal mean wind, and with differences in the radar observational time at each grid point within one volume scan are considered.This method is demonstrated to be feasible by applying it to recover the three-dimensional wind structure of a subtropical squall line from Doppler radar data, collected during the 1987 Taiwan Area Mesoscale Experiment (TAMEX).
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An investigation of the Moving-Frame single-Doppler wind retrieval technique using Taiwan Area Mesoscale Experiment low-level data
Journal of Applied Meteorology, 2001Co-Authors: Yu-chieng Liou, Ing-shiang LuoAbstract:The Moving-Frame single-Doppler radar wind retrieval technique is investigated using field experimental data observed during the 1987 Taiwan Area Mesoscale Experiment intensive observation period 2. Emphasis is placed on studying the impact of the geometric position of the radar in relation to the quality of the retrievals. Experiments show that this technique is capable of recovering the missing cross-beam wind components, but their magnitude is always underestimated. As a consequence, when the unobserved tangential components are smaller than the observable radial components, the best results are produced. By contrast, if the unknown cross-beam winds considerably exceed the radial winds because of a disadvantageous relationship to the radar observation site, the retrievals become less reliable. However, even without a priori knowledge of the true flow structure, which is always the case in reality, this single-Doppler retrieval scheme demonstrates its ability to distinguish which component (radial or azimuthal) is greater. In other words, when the tangential component completely dominates the radial winds, this message can be correctly delivered through the retrieval algorithm to alert the users so that the radar data and these single-Doppler-retrieved results will be interpreted and used with caution.
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SINGLE RADAR RECOVERY OF CROSS-BEAM WIND COMPONENTS USING A MODIFIED Moving Frame OF REFERENCE TECHNIQUE
Journal of Atmospheric and Oceanic Technology, 1999Co-Authors: Yu-chieng LiouAbstract:Abstract The Moving Frame of reference technique is modified so that the unobserved cross-beam wind components can be retrieved, with high resolution, from data measured by either single-Doppler or conventional radar. In this modified algorithm the reflectivity fields detected by consecutive radar scans are used to find a Moving Frame of reference for which the reflectivity measurements are as stationary as possible. After interpolating all of the observational data onto this optimal Moving Frame and assuming that the wind field is in a steady state for several radar scans, one can formulate a cost function that contains the following weak constraints: 1) conservation of reflectivity; 2) a geometric relationship between the radial velocity Vr and its Cartesian components u, υ, w; 3) incompressibility; and 4) small vertical vorticity. By minimizing this cost function, a complete three-dimensional wind field can be constructed. Using simulated data to test this method against the original Moving-Frame techn...
Igor A. Bandos - One of the best experts on this subject based on the ideXlab platform.
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On pure spinor formalism for quantum superstring and spinor Moving Frame
Classical and Quantum Gravity, 2013Co-Authors: Igor A. BandosAbstract:The D=10 pure spinor constraint can be solved in terms of spinor Moving Frame variables v −� q and 8-component complex null vector � + , � + � + = 0, which can be related to the κ-symmetry ghost. Using this and similar solutions for the conjugate pure spinor and other elements of the non-minimal pure spinor formalism we present a (hopefully useful) reformulation of the measure of the pure spinor path integral for superstring in terms of products of Cartan form corresponding to the coset of 10D Lorentz group and to the coset of complex orthogonal group SO(8,C). Our study suggests a possible complete reformulation of the pure spinor superstring in terms of new irreducible set of variable.
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Spinor Moving Frame, M0-brane covariant BRST quantization and intrinsic complexity of the pure spinor approach
Physics Letters B, 2008Co-Authors: Igor A. BandosAbstract:Abstract To exhibit the possible origin of the inner complexity of the Berkovits's pure spinor approach, we consider the covariant BRST quantization of the D = 11 massless superparticle (M0-brane) in its spinor Moving Frame or twistor-like Lorentz harmonics formulation. The presence of additional twistor-like variables (spinor harmonics) allows us to separate covariantly the first and the second class constraints. After taking into account the second class constraints by means of Dirac brackets and after further reducing the first class constraints algebra, the dynamical system is described by the cohomology of a simple BRST charge Q susy associated to the d = 1 , n = 16 supersymmetry algebra. The calculation of the cohomology of this Q susy requires a regularization which implies the complexification of the bosonic ghost associated to the κ -symmetry and further leads to a complex (non-Hermitian) BRST charge Q ˜ susy which is essentially the ‘pure spinor’ BRST charge Q B by Berkovits, but with a composite pure spinor.
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Green-Schwarz superstrings in spinor Moving Frame formalism
Physics Letters B, 1992Co-Authors: Igor A. Bandos, A.a. ZhelukhinAbstract:Abstract Green-Schwarz superstring theory in D = 4 and D = 10 is formulated in an extended space including additional spinor coordinates of the Cartan Moving Frame. These spinor coordinates, realized in the form of the Lorentz harmonics, are used for constructing covariant irreducible generators of fermionic k -symmetry. Generalizations of the suggested superstring formulations for the cases of super- p -brane theories in the D -dimensional space time including the D = 11 supermembrane are discussed.
Stine Skov Madsen - One of the best experts on this subject based on the ideXlab platform.
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Asymptotically Matched Layer (AML) for transient wave propagation in a Moving Frame of reference
Computers and Geotechnics, 2017Co-Authors: Stine Skov Madsen, Steen KrenkAbstract:Abstract The paper presents an Asymptotically Matched Layer (AML) formulation in a Moving Frame of reference for transient dynamic response of a multi-layer 2D half-space. A displacement based finite element formulation of the convected domain problem is presented together with the AML formulation in which the original convolution integrals are represented via two auxiliary displacement-like state-space variables. A parametric study of the AML parameters is conducted for optimizing the absorbing properties. The performance is demonstrated on a single- and a two-layered half-space for various velocities of an impulse Ricker load. Excellent absorbing properties are demonstrated in both half spaces.
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PERFECTLY MATCHED LAYER (PML) FOR TRANSIENT WAVE PROPAGATION IN A Moving Frame OF REFERENCE
2014Co-Authors: Stine Skov Madsen, Steen Krenk, Ole HededalAbstract:In relation to the development of a Rolling Wheel Deflectomet er (RWD), which is a non-destructive testing device for measuring pavementdeflections, a finite element model for obtaining the soil/pavement response is developed. Abs orbing boundary conditions are necessary in order to prevent reflections of the waves propaga ting through the soil due to the dynamic loading. The Perfectly Matched Layer (PML) has prov en to be highly efficient when solving transient wave propagation problems in a fixed mesh. H owever, since the RWD is operating at traffic speeds, the load is Moving with high speedand a formulation in a Moving mesh is therefore more convenient. In this paper, a formulat ion of the PML is developed in the Moving Frame of reference. Numerical results are presented f or a single layer and a double layer half space, respectively, subjected to a Moving load o different velocities.
