Modes Of Body Research Articles

Deep Video‐Based Performance Synthesis from Sparse Multi‐View Capture

AbstractWe present a deep learning based technique that enables novel‐view videos of human performances to be synthesized from sparse multi‐view captures. While performance capturing from a sparse set of videos has received significant attention, there has been relatively less progress which is about non‐rigid objects (e.g., human bodies). The rich articulation modes of human body make it rather challenging to synthesize and interpolate the model well. To address this problem, we propose a novel deep learning based framework that directly predicts novel‐view videos of human performances without explicit 3D reconstruction. Our method is a composition of two steps: novel‐view prediction and detail enhancement. We first learn a novel deep generative query network for view prediction. We synthesize novel‐view performances from a sparse set of just five or less camera videos. Then, we use a new generative adversarial network to enhance fine‐scale details of the first step results. This opens up the possibility of high‐quality low‐cost video‐based performance synthesis, which is gaining popularity for VA and AR applications. We demonstrate a variety of promising results, where our method is able to synthesis more robust and accurate performances than existing state‐of‐the‐art approaches when only sparse views are available.

Researches on the resonance of a new type of suspended monorail vehicle-bridge coupling system based on modal analysis and rigid-flexible coupling dynamics

This paper introduces a new type of suspended monorail developed in China with the advantages of both German and Japanese monorails. The FE (finite element) model of the bridge is built in Ansys and coupled with the multibody dynamic model of the vehicle in the UM (Universal Machine). software. FIALA formula is used to construct the tire model. Then, the vehicle-bridge coupling system of the new type suspended monorail is set up and simulated with Park method. The result of the modal analysis and vehicle-bridge coupling simulation draw the same conclusion that the span of the stiffeners could result in the resonance of the vehicle system, which is due to the coupling of the frequencies of the natural modes of the car body and bogie with that for vehicle passing through stiffeners. Through the multibody dynamic simulation of the vehicle-bridge coupling system, the modes of the bridge at the frequencies of 5–10, 15–25 and 30–40 Hz are easily excited when the vehicle passes through the bridge. The three constraint modes and free modes of the bridge are similar in these frequency ranges.

Investigation on the interaction mechanism and failure behavior between bolt and rock-like mass

The matching relationship between bolt diameter and borehole diameter determines the bolt supporting effect in the mining roadway. In this paper, the failure modes of the anchorage body under different diameter matching were studied by the pullout test. When the anchorage agent was pulled out completely with bolt, the anchoring effect was ideal. Whereas, when the bolt was pulled out smoothly with only a thin layer of anchorage agent, the anchoring effect was relatively worse. Through multiple pullout tests, the suitable diameter matching difference can be defined with a range of 6–11 mm. Based on the interface sliding failure mode between anchorage agent and rock-like mass, a mechanical model of diameter matching was established. Both equations of tensile force and interfacial shear stress along with the anchorage direction in perfectly elastic state were derived. FLAC 3D was applied to analyze the distribution of interfacial shear stress and axial stress under different diameter matching between the bolt and the borehole. As a result, a 4–11 mm diameter difference shows the best anchoring effect. According to both experimental and simulation results, the optimal diameter matching difference is 6–11 mm.

Effect of train speed and track geometry on the ride comfort in high-speed railways based on ISO 2631-1

The operational speeds of passenger trains have been increasing and now often exceed 300 km/h. Higher speeds can lead to increased vibration and reduced ride comfort for railway passengers. This study investigates the combined effect of speed and track geometry on vibration discomfort in high-speed trains. Railway vehicle dynamic models with various levels of complexity are used, with the measured geometry of a section of a high-speed track as an input. The models have been calibrated with vibration measurements carried out in a train running over this section of the track and then applied to predict the vibration discomfort at increased speeds. To evaluate the vibration discomfort at speeds up to 400 km/h, information on track geometry should include wavelengths up to at least 150 m. Vertical irregularities have the greatest effect at all speeds but lateral irregularities are also important. Both the vertical and lateral irregularities of a high-speed track should be controlled at wavelengths of 50–100 m that excite rigid modes of the car body, corresponding to frequencies of typically 1–2 Hz. Additionally, vertical irregularities with wavelengths of 5–12 m that excite the fundamental flexible mode of the car body, typically around 10–15 Hz, should also be controlled. The effects of cant, the rates of change of cant, and the radius of vertical curves are also evaluated although they only have a small effect on vibration discomfort.

The coupled effects of bending and torsional flexural modes of a high-speed train car body on its vertical ride quality

This study is focused on the effects of bending and torsional flexural modes of the car body on the ride quality index of a high-speed train vehicle. The Euler–Bernoulli beam model is used to extract an analytical model for a high-speed train vehicle car body in order to investigate its bending and torsional flexural vibrations. The rigid model includes a car body, two bogie frames, and four wheelsets such that, each mass has three degrees of freedom including vertical displacement, pitch motion, and roll motion. The results obtained with the proposed analytical model are compared with experimental measurements of the car body response of a Shinkansen high-speed train. Moreover, it is determined that the bending and torsional flexural modes have significant effects on the vertical acceleration of the car body, particularly in the 9–15 Hz frequency range. Furthermore, the ride quality index is calculated according to the EN 12299 standard and it is shown that the faster the train the more affected is the ride quality by the flexural modes. In addition, the effect of coherence between two rail irregularities (the right and the left rails) on the results of the simulation is investigated. The results conclude that if the irregularities are completely correlated the torsional flexural mode of the car body does not appear in the response. Also, the first bending flexural mode in such cases is more excited compared with the partially correlated or uncorrelated rail irregularities. Therefore, the ride quality index in completely correlated cases is higher than other cases.

Construction of simulation framework for dynamic analysis of a superconducting magnetic levitation train with flexible car bodies

Magnetic levitation (maglev) trains are eco-friendly and help to transport passengers efficiently and safely. Among two main types of maglev train, the EDS type is more appropriate for ultra-high-speed maglev trains. However, it has disadvantages with regard to vertical and lateral stability induced by external and internal vibrations. To analyze and evaluate the dynamics of ultra-high-speed maglev, we proposed a co-simulation framework for dynamic analysis of an EDS-type maglev with ultra-high-speed and all-flexible car bodies using couple-field analysis. First, electromagnetic forces were calculated with the superconducting coils and magnets using 2D analytic model. And a lookup table for electromagnetic forces was constructed with a large range of levitation from −100 mm to 100 mm and guidance from −50 mm to 50 mm. A rigid car body model was then constructed using a multi-body dynamics program. The flexible car body were modeled using the ANSYS program and converted using rigid body element (RBE2 element). The total simulation framework was constructed using MATLAB Simulink, and the dynamic models, electromagnetic model and lookup table were connected using a cosimulation process. The constructed co-simulation framework was used to investigate the dynamics of a high-speed train under conditions of random irregularity. As results, we found that the first bending and middle layer modes of the flexible car body mutually affected the vibration characteristics of the flexible car body compared to the rigid car body. In addition, flexible car bodies showed greater vibration than rigid car bodies because of elastic modal effects and additional vibration induced by the interactions of the car bodies.

Modelling rubber dynamic stiffness for numerical predictions of the effects of temperature and speed on the vibration of a railway vehicle car body

Using a viscoelastic model containing a temperature spectrum and a friction model, a nonlinear model of rubber elements has been developed and verified. It takes into account the correlation between temperature, vibration frequency, and vibration amplitude, its parameters are identified by conducting static tests and dynamic mechanical thermal analysis. Then, it is used in a dynamic model for high-speed railway vehicles containing suspended under-chassis equipment (UCE). The coupling between the vibrations of the car body and UCE that considers the temperature-dependent characteristics of the rubber elements is studied, and trends for the modal vibrational energy of the UCE and car body are identified. The results indicate that the decrease in the ambient temperature significantly increases the dynamic stiffness of the rubber elements, which impairs their function. It also generates more intense UCE vibrations and increases the vibrational energy of the low-frequency (first-order vertical bending and diamond-shaped deformation) modes of the car body, thus degrading the ride quality assessed via the Sperling index. At extremely high ambient temperature (around 40 °C), the dynamic stiffness and damping coefficient of rubber elements decreases, thus weakening the damping effect and increasing the vibration amplitudes of the car body and UCE. Considering the dynamic stiffness of the rubber elements at 20 °C as a reference, the dispersion of their dynamic stiffness should be maintained within the range [−20%, 50%] at temperatures between −30 and 40 °C to ensure good ride quality of the vehicle at running speeds above 300 km/h.

The results of research to clarify the process of cutting soil spherical disk working body

Purpose. Clarify the size and direction of cutting the soil, taking into account the influence of the coordinates of the instantaneous center of the disk on the rotation of its diameter at the time of its location in a vertical position. Methods. Using the provisions of physics, theoretical mechanics and resistance of materials. Results. The influence of the coordinates of the location of the instantaneous center of the disk on the angle of cutting of the soil by the points of the blade of the disk and the vectors of their trajectory in the soil medium is established, which makes it possible to more accurately determine the value of the angle of cutting of the soil depending on the parameters and operating modes of the spherical disk working body, and its smallest possible value was used in as an evaluation criterion in the selection and justification of rational parameters and operating modes of disk harrows. It has been established that the cutting angle γcut increases with decreasing angle of inclination of the disk β and an increase in the angle of attack α'. Conclusions 1. The direction of movement of the points of the blade of the disk in the soil medium is clarified due to the rotation of the diameter of the disk at the moment of its vertical location under the influence of the coordinates of the instant center, this is confirmed by the profile of the formation of the bottom of the furrow with a notched disk of the working body. 2. A refined dependence is obtained for determining the angle of soil cutting by the points of the blade of a spherical disk working body, which combines all its parameters and the smallest possible value of the angle of soil cutting, and the expediency of its use in the selection and justification of rational parameters of the working bodies of the disk harrow. Keywords: soil, soil environment, the spherical disc working body, the points of the blade of the disk, the speed of movement of points of the blade of the disk, the cutting angle of the soil, the angle of attack, the angle of inclination of the disk to the vertical.

Operational parameters and modes of rotary working body for harrowing crops

A rotary working body with evenly spaced needles along perimeter is a flat disk (rotating in longitudinal–vertical plane). The technological process of interaction with soil is that when rolling rotary disk in soil layer, needle is introduced into it, crushing and shifting soil in direction of rotation. The degree of soil loosening of freely rotating needle disk on axis in longitudinal–vertical plane depends on several parameters: diameter of a disk, number and shape of needles, speed of progressive motion, soil properties. There was made an analytical research of needle working bodies in terms of influence of sizes of disk and needles on process of their interaction with soil.

Modal analysis and optimization of bus body structure

To study the vibration and noise of the bus, the structural and the relevant acoustic models of the bus body are firstly established. Then, their resonant frequencies and crucial modes of vibration are analyzed. The stiffness, mass and natural frequency of the studied beams are varied to optimize the vibration frequencies and modes of the bus body. The results provide valuable guidelines for the modal analysis and optimization of the bus body structures.

A model for the observed decorrelation of partials in the overtone spectra of bowed stringed instruments

It has been shown that the overtone frequencies in the spectra of bowed stringed instruments played with vibrato exhibit less than perfect pairwise correlations. However, these results are inconsistent with the mechanism of performing vibrato by changing the length of the string. Since modulating the string length affects the frequencies of all string modes proportionately, it is curious that the overtones exhibit less than perfect correlations. The observed decorrelations, therefore, may be attributed to the filtering of the string’s vibrations by the mechanical-acoustic resonant modes of the instrument body. The exact frequency deviations depend upon the frequencies of instrument’s resonant modes in relation to the string’s overtone frequencies and the width and rate of the vibrato. By modelling the instrument body as a sum of resonant modes driven by a frequency modulated saw tooth wave, we develop an analytical model relating the observed frequency deviations to the modal properties of the instrument....

Optimised PID control for tilting trains

ABSTRACTNulling-type tilt control in tilting railway vehicles, i.e. Single-Input–Single-Output (SISO) control using non-precedent sensor information for lateral acceleration and tilt angle, suffers from performance limitations due to the system's non-minimum phase characteristics [Zolotas, A. C., & Goodall, R. M. (2000). Advanced control strategies for tilting railway vehicles. UKACC international conference on control, University of Cambridge, Cambridge, UK. 6p., ISBN: 0-85296-240-1.]. From an engineering point of view, this is due to the suspension's dynamic interactions and the sensor information used for feedback control. This paper revisits SISO PID-based nulling-type tilt control design (hereby referred to as ‘economical tilt control’) and rigorously studies its design via optimization to improve system performance. The strong coupling between the roll and lateral dynamic modes of the vehicle body is shown and the performance limitations using conventional control highlighted. PID controllers are designed to illustrate different levels of tilt performance regarding the deterministic (curving acceleration response) and stochastic (ride quality) with the latter being a bounded constraint. With novel contribution to use of PID control in the tilt control application with rational transfer functions, particular emphasis is placed on the practical aspects of the tilt dynamics within the design framework via detailed simulation results.

Theoretical concepts of unlimited-power reflectors, absorbers, and emitters with conjugately matched layers

In order to ensure the fastest wireless energy transfer from a source to the user one needs to maximize the channel capacity for power transport. In communications technologies, the concept of MIMO (multiple input, multiple output) exploits the idea of sending signals via many different rays which may reach the receiver. However, if we are concerned with the task of energy transfer, still only one mode is exploited, even if multiple antennas are used to send power to the receiver. In the near-field scenario, this is the magnetic dipole mode of receiving coil antennas. In the far-field scenario, this is the propagating plane wave TEM mode. Recently, it was shown that using special artificial materials it is possible to ensure that all electromagnetic modes of free space are conjugately matched to the modes of a material body and, thus, all modes deliver power to the body in the most effective way. Such a fascinating feature is acquired because the conjugate matching does not concern only the propagating modes but, most importantly, is applied to all evanescent modes. However, coupling to higher-order (mostly evanescent) modes is weak and disappears in the limit of an infinite planar boundary. We show that properly perturbing the surface of the receiving or emitting body with, for example, randomly distributed small particles we can open up channels for super-radiation into far zone. The currents induced in the small particles act as secondary sources which send the energy to travel far away from the surface and, reciprocally, receive power from far-located sources. We theoretically predict about 20-fold power transfer enhancement between the conjugately matched power-receiving body (as compared with the ideal black body) and far-zone sources. Reciprocally, the proposed structure radiates about 20 times more power into far zone as compared with the same source over a perfect reflector.

Understanding of Major Dynamic Modes of Automotive Body by the Principal Modal Analysis

Understanding of Major Dynamic Modes of Automotive Body by the Principal Modal Analysis

Fluid force and symmetry breaking modes of a 3D bluff body with a base cavity

A cavity at the base of the squareback Ahmed model at Re≃4×105 is able to reduce the base suction by 18% and the drag coefficient by 9%, while the flow at the separation remains unaffected. Instantaneous pressure measurements at the body base, fluid force measurements and wake velocity measurements are investigated varying the cavity depth from 0% to 35% of the base height. Due to the reflectional symmetry of the rectangular base, there are two Reflectional Symmetry Breaking (RSB) mirror modes present in the natural wake that switch from one to the other randomly in accordance with the recent findings of Grandemange et al. (2013b). It is shown that these modes exhibit an energetic 3D static vortex system close to the base of the body. A sufficiently deep cavity is able to stabilize the wake toward a symmetry preserved wake, thus suppressing the RSB modes and leading to a weaker elliptical toric recirculation. The stabilization can be modelled with a Langevin equation. The plausible mechanism for drag reduction with the base cavity is based on the interaction of the static 3D vortex system of the RSB modes with the base and their suppression by stabilization. There are some strong evidences that this mechanism may be generalized to axisymmetric bodies with base cavity.

Experimental analysis of the oscillations of a mechanical system with self-synchronized inertial vibration exciters

This article describes the results of experimental studies of oscillations in a classical singlemass oscillation system on a spring suspension with two unbalanced mass vibration generators in a wide range of excitation frequencies. The testing technique is described, and the results are analyzed in detail. It is shown that there is an effect of self-oscillatory adaptive self-synchronization of imbalances for changes in the oscillation modes of the lifting body, depending on the excitation frequency in the mechanical system.

Cartesian Modes and The Simplicity of Mind

AbstractMalebranche argues that we lack a clear idea of the mind because we cannot, even in principle, derive all the possible modes of mind solely from the idea of thought. But we can, in principle, derive all the possible modes of body from the idea of extension. Therefore, there is epistemic asymmetry between our ideas of mind and body. I offer a defense of Descartes whereby he can assert that we have a clear idea of mind despite this asymmetry. I argue that he can do this by distinguishing the simplicity of mind from the divisibility of body.

Amplification of optical phonons in narrow band semiconductors at low temperatures

Terahertz radiation generation by using the natural modes of solid body has been investigated. The numerical simulation of instability of terahertz range optical phonons in semiconductor structures with quantum wells during the drift of two-dimensional electron gas was performed. The main obstacle of implementing the specified instability is the heating of electron gas during its drift. That is why the investigations were performed for low temperatures T < 77 K, and the electron gas was assumed to be degenerate. Due to the existing closed cycle microcoolers and also the feedback implementation, it is possible to experimentally observe the generation of optical phonons. The numerical simulation involved the use of both kinematic and hydrodynamic approaches. It has been shown that the kinetic approach is more adequate, while the hydrodynamic one leads to overestimated values of instability increments.

Electrically Small UAV Antenna Design Using Characteristic Modes

This paper presents a novel concept of antenna design for an electrically small unmanned aerial vehicle (UAV) using the theory of characteristic modes. With the knowledge of the characteristic modes of the UAV body, a multi-objective evolutionary algorithm is implemented to synthesize currents on the UAV body for achieving desired power patterns. Compact and low-profile feed structures are then designed to excite the synthesized currents. The feed structures are termed as probes, as they are used to excite the currents on the UAV body and cannot work as standalone antennas. The UAV body excited by these probes serves as the radiating aperture. Its reconfigurable radiation patterns are obtained by feeding each probe with proper magnitude and phase. In this method, the aperture of the UAV body is fully utilized. Practical issues associated with large antennas at low frequency band are eliminated. Knowledge for probe placement on such platform becomes more explicit. Simulated and measured results are presented to verify the design concept.

Toward Transpacific Ecopoetics: Three Indigenous Texts

In this article, I employ "the Pacific" as a contact zone, method, and concept with which to examine the dynamic, shifting relationship between land and sea that allows indigenous literature in the transpacific context to engage all of its ecopoetic complexity. The Pacific is the largest oceanic divide on earth. In recent years, issues around global capitalism, national identity, community, and the ecology of the Pacific region have sparked intriguing and provoca- tive discussions. Research along these lines celebrates the networking and coalition activities of various groups of people in the Pacific, and highlights the circulation of ideas and cultures that I believe to be crucial to contem- porary ecological scholarship. It offers an oceanic perspective that serves as a counterweight to continental ways of thinking, and it supplements or challenges transnational approaches to imperialism, postcolonialism, indi- geneity, globalization, and ecology. 1 A recent special issue of the Contemporary Pacific titled "Native Pacific Cultural Studies on the Edge" examines uncharted spaces of the Pacific Islands and historicizes indigenous discourses about making landfall, showing how they have contested the production of new transoceanic environments. The articles in this special issue "explore notions of Pacific indigeneity as they circulate through geographical, cultural, political, and historical flows of people(s), things, knowledge, power—between islands and continents." 2 As the United States and China battle over this geographical space, the message from the indigenous Pacific can be inspiring: neighboring communities have always exchanged ideas and products, often across vast oceanic distances. It was a large world in which indigenous people intermingled along numerous interconnecting routes, unhindered by the boundaries erected much later by imperial powers. Indeed, the recent wave of research on transnational