Motion Of Different Parts Research Articles

Human Activity Classification Based on Dual Micro-Motion Signatures Using Interferometric Radar

Micro-Doppler signatures obtained from the Doppler radar are generally used for human activity classification. However, if the angle between the direction of motion and radar antenna broadside is greater than 60°, the micro-Doppler signatures generated by the radial motion of human body reduce significantly, thereby degrading the performance of the classification algorithm. For the accurate classification of different human activities irrespective of trajectory, we propose a new algorithm based on dual micro-motion signatures, namely, the micro-Doppler and interferometric micro-motion signatures, using an interferometric radar. First, the motion of different parts of the human body is simulated using motion capture (MOCAP) data, which is further utilized for radar echo signal generation. Second, time-varying Doppler and interferometric spectrograms obtained from time-frequency analysis of a single Doppler receiver and interferometric output data, respectively, are fed as input to the deep convolutional neural network (DCNN) for feature extraction and the training/testing process. The performance of the proposed algorithm is analyzed and compared with a micro-Doppler signatures-based classifier. Results show that a dual micro-motion-based DCNN classifier using an interferometric radar is capable of classifying different human activities with an accuracy level of 98%, where Doppler signatures diminish considerably, providing insufficient information for classification. Verification of the proposed classification algorithm based on dual micro-motion signatures is also performed using a real radar test dataset of different human walking patterns, and a classification accuracy level of approximately 90% is achieved.

Modulation transfer functions for audiovisual speech.

Temporal synchrony between facial motion and acoustic modulations is a hallmark feature of audiovisual speech. The moving face and mouth during natural speech is known to be correlated with low-frequency acoustic envelope fluctuations (below 10 Hz), but the precise rates at which envelope information is synchronized with motion in different parts of the face are less clear. Here, we used regularized canonical correlation analysis (rCCA) to learn speech envelope filters whose outputs correlate with motion in different parts of the speakers face. We leveraged recent advances in video-based 3D facial landmark estimation allowing us to examine statistical envelope-face correlations across a large number of speakers (∼4000). Specifically, rCCA was used to learn modulation transfer functions (MTFs) for the speech envelope that significantly predict correlation with facial motion across different speakers. The AV analysis revealed bandpass speech envelope filters at distinct temporal scales. A first set of MTFs showed peaks around 3-4 Hz and were correlated with mouth movements. A second set of MTFs captured envelope fluctuations in the 1-2 Hz range correlated with more global face and head motion. These two distinctive timescales emerged only as a property of natural AV speech statistics across many speakers. A similar analysis of fewer speakers performing a controlled speech task highlighted only the well-known temporal modulations around 4 Hz correlated with orofacial motion. The different bandpass ranges of AV correlation align notably with the average rates at which syllables (3-4 Hz) and phrases (1-2 Hz) are produced in natural speech. Whereas periodicities at the syllable rate are evident in the envelope spectrum of the speech signal itself, slower 1-2 Hz regularities thus only become prominent when considering crossmodal signal statistics. This may indicate a motor origin of temporal regularities at the timescales of syllables and phrases in natural speech.

Analysis and Simulation of the Micro-Doppler Signature of a Ship With a Rotating Shipborne Radar at Different Observation Angles

Differences in the motion of different parts of a target cause the echo signal to contain specific Doppler modulation information, i.e., the micro-Doppler (m-D) effect. This phenomenon provides an effective way to detect targets in marine environments. In this study, based on the establishment of the micromotion model of a rotating surveillance radar and analysis of the m-D frequency, the geometrical optics and physical optics (GO-PO) method and the time-frequency analysis technique are used to obtain the radar cross section (RCS) and m-D signature of a ship with a shipborne radar at different observation angles. The ship, as the main component of the echo, is associated with the main energy. Finding the optimum angle to observe the shipborne radar is of great importance. The results show that the m-D signatures of the shipborne radar are not clear when the elevation angle is greater than 60° but are clear when the elevation angle is less than 55°. Moreover, some motion parameters can be extracted from the m-D signature, such as the period of the ship micromotion. The rotation speed of the shipborne radar can be obtained and is consistent with the set speed. This can help identify and track the key parts of a ship with local motion.

Unsteady turbulent flow developing inside and around different parts of fluttering trawl net in flume tank

Fluttering motions of a trawl are affected by its geometrical shape, natural underwater flows, and unsteady turbulent flow inside and around it. Thus, knowledge of the interaction between fluttering motions and the turbulent flow developing inside and around the different parts of the trawl is essential for understanding the hydrodynamic performance and selectivity of fishing gear. This paper assesses the coupled dynamics of the fluttering motions of different parts of a trawl and their hydrodynamics behavior. The analysis is based on three-dimensional electromagnetic current velocity meter measurements carried out inside and around different parts of a 1/18 scaled bottom trawl model. Instantaneous flow velocity fields and turbulent flow parameters were analyzed from obtained flow data. Moreover, fast Fourier transform and wavelet transform analysis were conducted to analyze the time–frequency contents of instantaneous flow velocity fields and fluctuating parts. The motions of different parts of the trawl net were oscillatory quasi-periodic and related to low frequency activity. The mean velocity ratios inside and around trawl wing, square, trawl body, and codend were 0.92, 0.89, 0.86, and 0.84, respectively. These results demonstrate the existence of unsteady turbulent flow inside and around different parts of the trawl. This unsteady turbulent flow corresponds to turbulent boundary layer flow, turbulent flow because of trawl wake, and vortex shedding. The dominant frequencies of these unsteady turbulent flows showed low frequency activities and wavelet energy was transferred from small-scale to large-scale motions under unsteady shear turbulence. In addition, knowledge of unsteady turbulent flow is greatly important for better understanding the hydrodynamic forces acting on a trawl and its geometrical shape as well as for implementing various selective devices and mesh shapes to reduce juvenile by-catch.

Fibrous inductance strain sensors for passive inductance textile sensing

Stretchable strain-sensitive textiles that can detect human motion and physiological information in real time have considerable potential for application in next-generation wearable electronic devices. However, the application of such textiles has been hindered largely by their vulnerability to magnetic and electrical interference, wear and tear, and baseline drift. In this article, we report a new type of highly retractable and stretchable inductive sensor with a notable reciprocal change in inductance during stretching and recovery. Our experiments indicate that yarn sensors with a small diameter (627.4 μm) have high sensitivity (0.4 μH/%), fast response (<0.1 s), and stable performance without baseline drift after 4000 cycles of testing. The mechanical performance of the strain sensors was analyzed based on a viscoelastic mechanical model. From the derived effective stress-lifespan curve, the strain sensors can undergo 2.2 × 106 cycles of stretching and recovery with only a 5% reduction in performance. Our flexible yarn sensors can be used for monitoring motion in different parts of the body using the self-inductance effect. On the other hand, by employing mutual inductance to couple the sensors and an external readout coil, strians can also be monitored passively. Thus, these capabilities facilitate new methods for all-in-one wearable motion sensing with potential applications in the field of passive sensing in electronic textiles.

Flexible Gait Recognition Based on Flow Regulation of Local Features Between Key Frames

The information contained in gait frames is different, and the contribution of different frames to recognition tasks is also different. However, each frame has the same degree of attention in the input layer, this prevents the network from focusing on keyframes. Therefore, we propose a keyframe extraction module via information weighting, make network can pay more attention to the high contribution frame at the input layer, and the extraction of the distinctive features is improved. Moreover, the range of motion in different parts of the human body is different, the temporal and spatial correlation of local feature between silhouettes is different. Based on the discovery, we propose a Local Features Flow Regulation module to calculate the correlation coefficient of the local features of each silhouette, and the regulation coefficient is generated by the correlation coefficient. The regulation coefficient is applied to regulate the flow of local features, this enables the network to capture areas with more spatial and temporal features. Through the extraction of frame-level features and the interaction of local features between frames, the network can extract the most discriminative features from global to local flexibly. During training, each horizontal part is trained separately. The training can adjust the regulation coefficients, and the network is more flexible and expressive. Our model has a good performance on cross-viewing and complex environments of CASIA-B dataset. In the case of normal environment and complex environment (pedestrian with backpacks and in coats), the rank-1 of the proposed model is 95.1%, 87.9% and 74.0% respectively, higher than state-of-the-art.

Towards Artificial Emotions to Assist Social Coordination in HRI

Coordination of human–robot joint activity must depend on the ability of human and artificial agencies to interpret and interleave their actions. In this paper we consider the potential of artificial emotions to serve as task-relevant coordination devices in human–robot teams. We present two studies aiming to understand whether a non-humanoid robot can express artificial emotions in a manner that is meaningful to a human observer, the first based on static images and the second on the dynamic production of embodied robot expressions. We present a mixed-methods approach to the problem, combining statistical treatment of ratings data and thematic analysis of qualitative data. Our results demonstrate that even very simple movements of a non-humanoid robot can convey emotional meaning, and that when people attribute emotional states to a robot, they typically apply an event-based frame to make sense of the robotic expressions they have seen. Artificial emotions with high arousal level and negative valence are relatively easy for people to recognise compared to expressions with positive valence. We discuss the potential for using motion in different parts of a non-humanoid robot body to support the attribution of emotion in HRI, towards ethically responsible design of artificial emotions that could contribute to the efficacy of joint human–robot activities.

Millimeter-Wave Doppler Spectrum and Polarimetric Response of Walking Bodies

In this paper, the Doppler spectra of the radar backscatter response of human body and a quadruped are presented at W-band frequencies. This study is motivated by the desire to utilize millimeter-wave radars to detect pedestrians against other targets in the radar scene. The approach is based on dissecting the radar backscatter to isolate the radar returns from different body parts. The forward model is based on an iterative physical optics approach. The complex motion of different parts of walking bodies and their amplitude and range of motion is directly reflected in their radar cross section (RCS) and Doppler spectrum bandwidth. It is shown that the Doppler spectra and RCS differences are sufficient to distinguish a walking human from stationary and other moving objects. Radar polarimetry in conjunction with time-frequency analysis is examined as a method for detecting concealed carried objects. The overall backscatter is decomposed into components associated with the limbs and torso which are then utilized to enhance target detection.

A statistical physics perspective on the evolution of ion distributions across low Mach number quasi-perpendicular collisionless shocks

[1] The heating of directly transmitted ions at low Mach number, perpendicular and quasi-perpendicular shocks has been the subject of previous statistical physics studies. In this paper, we use a Hamiltonian formulation of the ion kinetics for a quasi-perpendicular shock model to derive the general solution to Liouville's equation as a function of six invariants, finding forms of these invariants in terms of the upstream parameters. The ion distribution is expressed as a function of one of these invariants, subject to a Maxwellian upstream boundary condition, and the evolution of the distribution through and downstream of the shock is studied. The momentum-space volume within surfaces of constant probability (related to the temperature) is shown to be inversely proportional to an average value of the canonical momentum associated with motion in the direction normal to the shock plane, generalizing a previous result to three-dimensional phase space. We also study the evolution of the distribution properties numerically, in particular noting that the “twisting” of these surfaces in phase space is the result of the unequal guiding center motion of different parts of the distribution (which is not the case for a fully perpendicular shock). This property provides insight into the damping of oscillations in the mean momentum and the temperature for a quasi-perpendicular model (as the distribution is spread about the central value through gyration) and the observed T⊥ > T∥ anisotropy.

SU‐FF‐J‐108: A Non‐Invasive Respiratory Motion Compensation System for Predicting Organ Motion in Respiratory‐Gated Radiotherapy of the Chest

Purpose: Non‐invasive respiratory gated radiotherapy systems, like those based on external anatomic motion, give better comfort to patients than invasive system during treatment. But to treat efficiently, such systems need a higher correlation between the motion of the external and internal anatomy. So we developed the system to track the motion and compensate for the correlation between internal and external anatomy to accurately predict the dynamic position of internal structures such as the diaphragm and tumor. Method and Materials: The respiratory motion compensation apparatus consists of two image boards, a camera and a fluoroscopy system. The camera and one of the image boards captures the abdominal motion of the patient, while the other image board captures the motion of internal anatomy through the fluoroscopy system. Software interfaced to the camera and fluoroscopy tracks the internal anatomy targets and abdominal surface motion induced by respiration simultaneously, using only image processing without any additional physical markers. The fluoroscopic movie was analyzed to obtain the correlation of internal and external anatomy motion in different parts of the diaphragm, abdominal surface and tumor where possible. Using this correlation coefficient, motion of the internal structures in later sessions was predicted based on the same point of abdominal surface motion. Results: The range of standard deviations between the predicted positions and the observed positions of some sample structures in each patient was measured about in phase and out of phase respectively. The difference between the predicted and observed positions of the abdominal surface, diaphragm or tumor was reduced a maximum 10 mms under the out of phase to 2mms under the in phase. Conclusion: This non‐invasive respiratory motion compensation system accurately predicts the respiratory motion of internal structures within 2 mms. Thus, this may improve the accuracy of gated or conventional 3D conformal radiotherapy.

Temperature dependance of properties of star-branched polymers: A computer simulation study

Dynamic Monte Carlo simulations of single star-branched polymer models were made. Star macromolecules were confined to a simple cubic lattice with the nearest-neighbor attractive interactions. Every star consisted of f=3 arms of equal length. Length of a star varied between 49 and 799 statistical segments. Static and dynamic properties of model stars were calculated in good solvent conditions, Θ-state and in the collapsed state. Change of the chain dimensions, diffusion coefficients, and their scaling exponents with the temperature was shown and discussed. The locations of the Θ temperature and the collapse transition temperature TC were estimated for all chain lengths under consideration. The differences in motion of inner and outer parts of a star-branched polymer in different solvent conditions were described. The existence of a high-density core in the center of star macromolecules was confirmed and the influence of the temperature on its magnitude was studied. An analysis of motion of different parts of star polymers and of the number of inter- and intra-armal contracts was performed.

How long does DNA keep the memory of its conformation? A time-dependent canonical correlation analysis of molecular dynamics simulation

The time dependence of the correlation between motions of different parts of DNA is analyzed from a 200 ps molecular dynamics simulation of the double-stranded self-complementary d(CTGATCAG) in the B form. Each nucleotide is decomposed into three subunits corresponding to the furanose ring (SU), the base (BA), and the backbone (SK). The motion of each subunit is considered as the superimposition of rigid body translation, rigid body rotation, and internal deformation. Canonical time-dependent correlation functions calculated with coordinates describing the different components of the subunits motion are defined and computed. This allows us to probe how long a particular type of motion of one subunit influences the other types of motions of other subunits (cross correlation functions) or how long a particular subunit keeps the memory of its own conformation or location (autocorrelation functions). From auto-correlation analysis it is found that deformation decorrelates within a few tenths of picoseconds, rotational correlation times are on the order of 8 ps, while translational motions are long-time correlated. The deformation of a subunit is not correlated to the deformation of another one (at the 200 ps time scale of our simulation), but influences slightly their translation and orientation as time increases. © 1996 John Wiley & Sons, Inc.

How long does DNA keep the memory of its conformation? A time-dependent canonical correlation analysis of molecular dynamics simulation.

The time dependence of the correlation between motions of different parts of DNA is analyzed from a 200 ps molecular dynamics simulation of the double-stranded self-complementary d(CTGATCAG) in the B form. Each nucleotide is decomposed into three subunits corresponding to the furanose ring (SU), the base (BA), and the backbone (SK). The motion of each subunit is considered as the superimposition of rigid body translation, rigid body rotation, and internal deformation. Canonical time-dependent correlation functions calculated with coordinates describing the different components of the subunits motion are defined and computed. This allows us to probe how long a particular type of motion of one subunit influences the other types of motions of other subunits (cross correlation functions) or how long a particular subunit keeps the memory of its own conformation or location (autocorrelation functions). From autocorrelation analysis it is found that deformation decorrelates within a few tenths of picoseconds, rotational correlation times are on the order of 8 ps, while translational motions are long-time correlated. The deformation of a subunit is not correlated to the deformation of another one (at the 200 ps time scale of our simulation), but influences slightly their translation and orientation as time increases.

Broad-line n.m.r. investigation of molecular motion in solid boron trifluoride amine complexes

Broad-line n.m.r. investigations of a series of complexes of boron trifluoride with amine donor molecules (e.g., BF3· NH3) reveal the presence of molecular motion in the solid state. From the temperature dependence of the linewidths, activation energies are derived for the reorientation process. The observed values of the second moments of the absorption signals are compared with theoretical values calculated from the known X-ray structures assuming motion of different parts of the complexes. The motions are discussed in relation to the crystal and molecular structures of the various complexes.

Atomic Oscillations in the Statistical Approximation

The dipolar spectral distribution function, or the photoabsorption cross section, of atoms is derived in the statistical approximation starting from general dynamic equations describing the density fluctuations induced in the atom by an external field. Using a local form of the theory it is found that coherence between the motion in different parts of the atom causes a modification of the spectral function. The modification can be put in the form of a dispersion denominator, and if this denominator becomes small in certain frequency ranges, the absorption is enhanced by what can be identified as collective resonances of the atom as a whole.

Theory of ultrasonic attenuation in metals and magneto-acoustic oscillations

The attenuation of an ultrasonic wave by direct interaction with the conduction electrons in a metal is analyzed without making any special assumptions about the shape of the Fermi surface. The problem is reduced to a calculation of the currents set up in a stationary lattice by forces on the electrons, some real (due to electric fields) and some fictitious to describe the disturbances due to the passage of the wave. The fictitious forces have their origin in the relative motion of different parts of the metal and in the change in shape of the equilibrium form of the Fermi surface as a result of lattice deformation. It is assumed, as is valid for ultrasonic frequencies below about 10 9 c/s, that the electric fields serve to annul any electronic current relative to the lattice. The expressions obtained are qualitatively similar to the earlier results for a free-electron model, in particular the attenuation tends to a con­stant limit as the electronic free path becomes infinite. Only for a pure longitudinal wave is the limit simple in form and there it is determined by the Gaussian curvature and the mean square value of the deformation parameter round that zone of the Fermi surface on which the electrons move parallel to the wave front. The analysis is extended to cover the situation which arises in a transverse magnetic field, in the limit when the free path is long compared with the electronic orbit perimeters. The results are very complicated, but qualitatively similar to the free-electron results in the types of oscillatory behaviour predicted and in the limiting values of the attenuation as the magnetic field increases without limit; if there are open orbits present, however, the limiting behaviour is changed, the attenuation of longitudinal waves for instance tending to infinity as H 2 . Although the oscillatory behaviour may usually be governed by the extreme exten­sions of the Fermi surface in a direction normal to H and to the direction of propagation, it is suggested that this is not likely to hold if the deformation parameter is very variable over the Fermi surface, as is probable in the noble metals, and that the oscillations may then indicate the positions of parts of high deformability.

A Theory of the Linear Viscoelastic Properties of Dilute Solutions of Coiling Polymers

The necessary coordination of the motions of different parts of a polymer molecule is made the basis of a theory of the linear viscoelastic properties of dilute solutions of coiling polymers. This is accomplished by use of the concept of the submolecule, a portion of polymer chain long enough for the separation of its ends to approximate a Gaussian probability distribution. The configuration of a submolecule is specified in terms of the vector which corresponds to its end-to-end separation. The configuration of a molecule which contains N submolecules is described by the corresponding set of N vectors. The action of a velocity gradient disturbs the distribution of configurations of the polymer molecules away from its equilibrium form, storing free energy in the system. The coordinated thermal motions of the segments cause the configurations to drift toward their equilibrium distribution. The coordination is taken into account by the mathematical requirement that motions of the atom which joins two submolecules change the configurations of both submolecules. By means of an orthogonal transformation of coordinates, the coordination of all the motions of the parts of a molecule is resolved into a series of modes. Each mode has a characteristic relaxation time. The theory produces equations by means of which the relaxation times, the components of the complex viscosity, and the components of the complex rigidity can be calculated from the steady flow viscosities of the solution and the solvent, the molecular weight and concentration of the polymer, and the absolute temperature. Limitations of the theory may arise from the exclusion from consideration of (1) very rapid relaxation processes involving segments shorter than the submolecule and (2) the obstruction of the motion of a segment by other segments with which it happens to be in contact. Another possible cause of disagreement between the theory and experimental data is the polydispersity of any actual polymer; this factor is important because the calculated relaxation times increase rapidly with increasing molecular weight.

The Roentgen-ray Cardiograph

AN instrument is here described that will make separate X-ray exposures of the different phases of motion of the human heart through slits in a metal plate opaque to X-rays. A single X-ray film is made to register the motion in different parts of the heart during one or more cardiac cycles. By moving the photographic film underneath the multiple-slit plate, a series of exposures are produced on the film by the impinging X-rays through each slit. The heart and the slits are stationary with respect to each other so that the same heart area is always exposed in the same slit and the only motion recorded, therefore, is the lateral motion of the heart border itself. With this motion there is produced on the film a wave representing the movement of a definite portion of the heart lying above a particular slit. The use of a multiple-slit plate gives a number of such waves, indicating the motion of the different portions of the heart border, and these, taken collectively, outline the entire heart. The name “Roent...

An apparatus for the direct determination of accelerations

The question of the determination of the acceleration of the true motion of the ground in various seismic phenomena, or of the motion in different parts of buildings, bridges, and all kinds of artificial structures, due to explosions, shocks, or oscillations of the ground, has a considerable theoretical and practical interest, since the investigation of these accelerations serves as a guide in the study of the mechanical forces by which these movements are caused. The knowledge of these forces is particularly important in the design of buildings of all kinds in seismological areas, and also for the calculation of various elements (ties or reinforcements) of structures which are often subjected to vibrations caused by the action of powerful engines by shifting of large' masses (in the case of bridges or buildings on yielding foundations), by sudden shocks (in the case of ships armed with heavy guns), and so on. The problem of the determination of the true magnitude of the acceleration, however, presents great practical difficulties, especially in the case where the amplitudes of the motion are small and the oscillations of short period. The apparatus generally used for this purpose consists mainly of a pendulum—whether simple, horizontal, or elastic—according to the anticipated magnitude of the period and of the three components (two horizontal and one vertical) of the movement under investigation.

On the viscous theory of glacier motion

The first two sections of the present memoir are occupied with a critical examination of the theory advanced by De Saussure to account for the progressive motion of glaciers, which he considered as formed of masses of rigid and inflexible ice, and with the further explanations of that theory given by Ramaud, Bischoff, Agassiz, and Studer. The author, on the other hand, regarding these masses as possessing a considerable degree of plasticity, explains on that supposition the phenomena they present; and, in the third section of the paper, he relates a series of experiments which he carried on in the Mer de Glace, near Chamouni, in the summer of 1844, with a view to determine by direct measurement the relative motion of different parts of the glacier. This he accomplished by selecting a spot on the western side of the Mer de Glace, between Trelaporte and l’Angle, where the ice was compact and free from fissures, and erecting on the surface a row of posts at short distances from one another, in a line transverse to the general direction of the moving mass. He was thus enabled to discover by trigonometrical observations the movements of different points in this line; and he ascertained that they advanced more and more rapidly in proportion as they were distant from the sides of the glacier; and that when not under the influence of neighbouring crevasses, these motions were gradual and uninterrupted; as was shown by the lines carried through the posts forming, after the lapse of a few days, a continuous curve, of which the convexity was turned towards the lower end of the glacier.