Average Motion Research Articles

The MotoNet: A 3 Tesla MRI-Conditional EEG Net with Embedded Motion Sensors.

The MotoNet was built using polymer thick film (PTF) EEG leads and motion sensors on opposite sides in the same flex circuit. EEG/motion measurements were made with a standard commercial EEG acquisition system in a 3 Tesla (T) MRI. A Kalman filtering-based BCG correction tool was used to clean the EEG in healthy volunteers. MRI safety studies in 3 T confirmed the maximum heating below 1 °C. Using an MRI sequence with spatial localization gradients only, the position of the head was linearly correlated with the average motion sensor output. Kalman filtering was shown to reduce the BCG noise and recover artifact-clean EEG. The MotoNet is an innovative EEG net design that co-locates 32 EEG electrodes with 32 motion sensors to improve both EEG and MRI signal quality. In combination with custom gradients, the position of the net can, in principle, be determined. In addition, the motion sensors can help reduce BCG noise.

Operating indicators in diesels with reduced heat and energy losses

The foregoing explains the experimentally established fact that in a heat-insulated diesel engine, diffusion combustion is of great importance - both in terms of the share of heat release and the duration of combustion. To compensate for the decrease in the efficiency of a thermally insulated diesel engine due to an increase in the duration of combustion, the injection advance is increased. The economic effect achieved in this way by increasing the maximum cylinder pressure cannot be considered due to thermal insulation. For typical compression end temperatures in a thermally insulated diesel engine, diffusion combustion, especially in the near-wall layers, is limited by transfer processes. This fact, in addition to the need to eliminate re-enriched zones in the near-wall layers, urgently requires additional turbulization of the working fluid during mixture formation and combustion in thermally insulated engines. The difficulty in solving this problem lies in the fact that one of the most important turbulence generators is the intake process, and one of the most effective solutions is special intake channels. However, the averaged motion and turbulence in the combustor decay significantly during compression. This process is enhanced in a thermally insulated diesel engine due to an increase in the molecular viscosity of the air. The same applies to the generation of turbulence at the end of compression-beginning of expansion. Thus, turbulization of the charge in the combustion chamber of a thermally insulated diesel engine is an urgent problem.

Proper Motions of Water Masers in W49 N Measured by KaVA

We report the proper motions of 22 GHz water masers toward W49 N that were observed by the KVN and VERA Array (KaVA) during 2017 February–May. We found 263, 268, and 310 features in three successive epochs; they were distributed in a region of size 4 × 4 arcsec2. The strongest flux density was in the third epoch, and its averaged value was 18,090 Jy at V LSR +0.47 km s−1. For 102 H2O maser features, proper motion was detected across all three epochs. The average proper motions in R.A. and decl. offset were −0.352 and +0.890 mas yr−1, respectively. The morphology of the distribution of the H2O maser features was found to be a bipolar outflow structure with an inclination angle of 37° ± 13° to the line of sight, and the features were expanding from a well-defined outflow center. A model of the source combining expansion and rotation yielded a distance to W49 of 11.12 ± 0.96 kpc that is consistent with the results from trigonometric parallax. A redshifted lobe was situated in the northeast direction and a blueshifted lobe in the southwest direction. We also discussed the location of the powerful flaring H2O maser feature at V LSR = + 6 km s−1 and its possible mechanisms on the basis of spatial structures for the maser feature in VLBI maps observed with the KaVA, timed just before and during the rebrightening phase.

Non-conservative Solutions of the Euler-$$\alpha $$ Equations

The Euler- $$\alpha $$ equations model the averaged motion of an ideal incompressible fluid when filtering over spatial scales smaller than $$\alpha $$ . We show that there exists $$\beta >1$$ such that weak solutions to the two and three dimensional Euler- $$\alpha $$ equations in the class $$C^0_t H^\beta _x$$ are not unique and may not conserve the Hamiltonian of the system, thus demonstrating flexibility in this regularity class. The construction utilizes a Nash-style intermittent convex integration scheme. We also formulate an appropriate version of the Onsager conjecture for Euler- $$\alpha $$ , postulating that the threshold between rigidity and flexibility is the regularity class .

Extension of Ekman (1905) wind-driven transport theory to the β plane

Abstract. The seminal Ekman (1905) f-plane theory of wind-driven transport at the ocean surface is extended to the β plane by substituting the pseudo-angular momentum for the zonal velocity in the Lagrangian equation. When the β term is added, the equations become nonlinear, which greatly complicates the analysis. Though rotation relates the momentum equations in the zonal and the meridional directions, the transformation to pseudo-angular momentum greatly simplifies the longitudinal dynamics, which yields a clear description of the meridional dynamics in terms of a slow drift compounded by fast oscillations; this can then be applied to describe the motion in the zonal direction. Both analytical expressions and numerical calculations highlight the critical role of the Equator in determining the trajectories of water columns forced by eastward-directed (in the Northern Hemisphere) wind stress even when the water columns are initiated far from the Equator. Our results demonstrate that the averaged motion in the zonal direction depends on the amplitude of the meridional oscillations and is independent of the direction of the wind stress. The zonal drift is determined by a balance between the initial conditions and the magnitude of the wind stress, so it can be as large as the mean meridional motion; i.e., the averaged flow direction is not necessarily perpendicular to the wind direction.

Time evolution of Majorana corner modes in a Floquet second-order topological superconductor

We propose a practically feasible time-periodic sinusoidal drive protocol in onsite mass term to generate the two-dimensional~(2D) Floquet second-order topological superconductor, hosting both the regular $0$- and anomalous $\pi$-Majorana corner modes~(MCMs) while starting from a static 2D topological insulator/$d$-wave superconductor heterostructure setup. We theoretically study the local density spectra and the time dynamics of MCMs in the presence of such drive. The dynamical MCMs are topologically characterized by employing the average quadrupolar motion. Furthermore, we employ the Floquet perturbation theory~(FPT) in the strong driving amplitude limit to provide analytical insight into the problem. We compare our exact (numerical), and the FPT results in terms of the eigenvalue spectra and the time dynamics of the MCMs. We emphasize that the agreement between the exact numerical and the FPT results are more prominent in the higher frequency regime for close to the $0$-quasi-energy mode.

Diffusion Properties of a Brownian Ratchet with Coulomb Friction

The motion of a Brownian particle in the presence of Coulomb friction and an asymmetric spatial potential was evaluated in this study. The system exhibits a ratchet effect, i.e., an average directed motion even in the absence of an external force, induced by the coupling of non-equilibrium conditions with the spatial asymmetry. Both the average motion and the fluctuations of the Brownian particle were analysed. The stationary velocity shows a non-monotonic behaviour as a function of both the temperature and the viscosity of the bath. The diffusion properties of the particle, which show several time regimes, were also investigated. To highlight the role of non-linear friction in the dynamics, a comparison is presented with a linear model of a Brownian particle driven by a constant external force, which allows for analytical treatment. In particular, the study unveils that the passage times between different temporal regimes are strongly affected by the presence of Coulomb friction.

Human motion recognition based on Nano-CMOS Image sensor.

Human motion recognition is of great value in the fields of intelligent monitoring systems, driver assistance system, advanced human-computer interaction, human motion analysis, image and video processing. However, the current human motion recognition methods have the problem of poor recognition effect. Therefore, we propose a human motion recognition method based on Nano complementary metal oxide semiconductor (CMOS) image sensor. First, using the Nano-CMOS image sensor to transform and process the human motion image, and combines the background mixed model of pixels in the human motion image to extract the human motion features, and feature selection is conducted. Second, according to the three-dimensional scanning features of Nano-CMOS image sensor, the human joint coordinate information data is collected, the state variables of human motion are sensed by the sensor, and the human motion model is constructed according to the measurement matrix of human motions. Finally, the foreground features of human motion images are obtained by calculating the feature parameters of each motion gesture. According to the posterior conditional probability of human motion images, the recognition objective function of human motion is obtained to realize human motion recognition. The results show that the human motion recognition effect of the proposed method is good, the extraction accuracy is high, the average human motion recognition rate is 92%, the classification accuracy is high, and the recognition speed is up to 186 frames/s.

Implementation of triggered kilovoltage imaging for stereotactic radiotherapy of the spine for patients with spinal fixation hardware.

Mitigation of intrafraction motion (IM) is valuable in stereotactic radiotherapy (SRT) radiotherapy where submillimeter accuracy is desired. The purpose of this study was to investigate the application of triggered kilovoltage (kV) imaging for spine SRT patients with hardware by correlating kV imaging with patient motion and summarizing implications of tolerance for IM based on calculated dose. Ten plans (33 fractions) were studied, correlating kV imaging during treatment with pre- and post-treatment cone beam computed tomography (CBCT). Images were taken at 20-degree gantry angle intervals during the arc-based treatment. The contour of the hardware with a 1mm expansion was displayed at the treatment console to manually pause treatment delivery if the hardware was visually detected outside the contour. The treatment CBCTs were compared using retrospective image registration to assess the validity of contour-based method for pausing treatment. Finally, plans were generated to estimate dose volume objective differences in case of 1mm deviation. When kV imaging during treatment was used with the 1mm contour, 100% of the post-treatment CBCTs reported consistent results. One patient in the cohort exhibited motion greater than 1mm during treatment which allowed intervention and re-setup during treatment. The average translational motion was 0.35mm. Treatment plan comparison at 1mm deviation showed little differences in calculated dose for the target and cord. Utilizing kV imaging during treatment is an effective method of assessing IM for SRT spine patients with hardware without increasing treatment time.

MCSfM: Multi-Camera-Based Incremental Structure-From-Motion.

Fully perceiving the surrounding world is a vital capability for autonomous robots. To achieve this goal, a multi-camera system is usually equipped on the data collecting platform and the structure from motion (SfM) technology is used for scene reconstruction. However, although incremental SfM achieves high-precision modeling, it is inefficient and prone to scene drift in large-scale reconstruction tasks. In this paper, we propose a tailored incremental SfM framework for multi-camera systems, where the internal relative poses between cameras can not only be calibrated automatically but also serve as an additional constraint to improve the system robustness. Previous multi-camera based modeling work has mainly focused on stereo setups or multi-camera systems with known calibration information, but we allow arbitrary configurations and only require images as input. First, one camera is selected as the reference camera, and the other cameras in the multi-camera system are denoted as non-reference cameras. Based on the pose relationship between the reference and non-reference camera, the non-reference camera pose can be derived from the reference camera pose and internal relative poses. Then, a two-stage multi-camera based camera registration module is proposed, where the internal relative poses are computed first by local motion averaging, and then the rigid units are registered incrementally. Finally, a multi-camera based bundle adjustment is put forth to iteratively refine the reference camera and the internal relative poses. Experiments demonstrate that our system achieves higher accuracy and robustness on benchmark data compared to the state-of-the-art SfM and SLAM (simultaneous localization and mapping) methods.

Effect of the respiratory motion of pulmonary nodules on CT-guided percutaneous transthoracic needle biopsy.

Computed tomography (CT)-guided percutaneous transthoracic needle biopsy (PTNB) is highly affected by respiratory motion; however, respiratory motion of target nodule during the PTNB and its effect on CT-guided lung biopsy have not been studied. To investigate the effect of the respiratory motion of pulmonary nodules on CT-guided PTNB. We retrospectively reviewed the procedural CT scans of 426 pulmonary nodules that underwent PTNB during quiet breathing. Maximal and average respiratory motions were measured using the difference of table position of the targeted nodule between multiple procedural scans. Diagnostic performance, complications, and technical factors of PTNB in nodules with large motion (maximal motion >1 cm) were compared with those in nodules with small motion (≤1 cm). The mean maximal and average respiratory motions between tidal volume breathing were 5.4 ± 4.4 and 2.7 ± 2.6 mm, respectively. Sensitivity and accuracy were 93.1% and 96.1% in nodules with large motion, compared with 94.7% and 95.9% in nodules with small motion, respectively. Respiratory targeting (P < 0.001), needle modulation (P < 0.001), motion artifact of target (P < 0.001), target disappearance from scans (P < 0.001), and number of performed CT scans (P < 0.001) were significantly higher in the large motion group, with no significant difference in radiation dose and complications between the groups. The respiratory motion of pulmonary nodules during CT-guided PTNB may cause technical difficulties but does not affect diagnostic performance nor complications associated with PTNB.

Новый каталог орбит 152 галактических шаровых скоплений по данным Gaia EDR3

This paper provides a new catalog of orbits and their parameters for a practically complete list of currently known galactic globular clusters (GCs), compiled by Vasiliev (2019) based on the most accurate modern measurements of their velocities and positions. The integration of the orbits of 152 globular clusters for 5 Gyr was performed using the new average proper motions obtained from the Gaia EDR3 catalog (Vasiliev and Baumgardt, 2021) and new average distances (Baumgardt and Vasiliev, 2021) in the axisymmetric three-component potential with spherical bulge, disk component, and spherical dark Navarro-Frank-White halo (Bajkova and Bobylev, 2016). The new orbital parameters are compared with the orbital parameters constructed by us earlier (Bajkova and Bobylev, 2021) in the same gravitational potential using proper motions obtained from the Gaia DR2 catalog (Vasiliev, 2019) and with the distances from the Harris catalog (2010).

Remove Blur Image Using Bi-Directional Akamatsu Transform and Discrete Wavelet Transform

Purpose: Image is an imitation of everything that can be materialized, and digital images are taken using a machine. Although digital image capture uses machines, digital images are not free from interference. Image restoration is needed to restore the quality of the damaged image.Methods: Bi-directional Akamatsu Transform is proven to have an effective performance in reducing blur in images. Meanwhile, Discrete Wavelet Transform has been widely used in digital image processing research. We had been investigated the image restoration method by combining Bi-directional Akamatsu Transform and Discrete Wavelet Transform. Bi-directional Akamatsu Transform applied in Low-Low (LL) sub-band is the Discrete Wavelet Transform decomposition image most similar to the original image before decomposing. In this study, there are still shortcomings, including the determination of the values of N, up_enh, and down_enh, which are still manual. Manually setting the three values makes the Bi-directional Akamatsu Transform method not get the best results. With the use of machine learning methods can get better restoration results. Further testing is also needed for a more diverse and robust blur. The image data has a resolution of 256x256, 512x512, and 1024x1024. The image will be directly converted to a grey-scale image. The converted image will be given an attack model: average blur, gaussian blur, and motion blur. The image that has been attacked will apply two restoration methods: the proposed method and the Bi-direction Akatamatsu Transform. These two restoration images will then be compared using PSNR.Result: The average PSNR value from the restoration of the proposed method is 0.1446 higher than the average PSNR value from the restoration of the Bi-directional Akamatsu Transform method. When we compare it with the average PSNR value of the Akamatsu Transform restoration method, the average PSNR of the proposed method is 0.2084.Value: The combination of DWT and akamatsu transform results produce good PSNR values even though they have gone through the blurring method in image restoration.

Extended molecular dynamics: Seamless temporal coarse-graining and transition between deterministic and probabilistic paradigms

This article explores the formulation of evolution equations for atomistic systems where the time resolution is controlled at will. Based on a time-rescaled version of Hamilton’s equations of motion, the equations of motion of these systems are derived with adjustable time granularity. Also, using the Liouville formalism for Hamiltonian mechanics, the evolution equations are recast in probabilistic terms, opening the door to variational, Galerkin-type projections. The resulting approximation provides the governing equations for the average motion of the system as well as the evolution of a temperature-like variable that modulates the thermal, unresolved, vibrations of each particle. The balance between the resolved and unresolved motions is, by construction, adjustable at every instant and fully reversible. This kind of models can be used to study the behavior of atomistic systems at different time scales.

Particle trajectory of nonlinear progressive flexural-gravity waves in Lagrangian coordinates

In this paper, we study the particle dynamics of nonlinear flexural-gravity waves propagating in a finite water depth, which is the interaction between ice sheets and water flows. The nonlinear deformation of a floating elastic sheet is modeled by the Cosserat shell theory. The theoretical analysis is performed by a uniform asymptotic perturbation expansion. A third-order explicit parametric solution of particle trajectories in Lagrangian coordinates is presented. Taking the time average of particle motion, the mass transport velocity and the Lagrangian surface setup are also derived. Numerical simulations are computed. The influences of flexural rigidity on the water particle orbits and the mass transport velocity of nonlinear flexural-gravity waves are first discussed.

Outcomes of single digit replantation for amputation proximal to the flexor digitorum superficialis insertion: A systematic review with meta-analysis.

A single digit amputated proximal to the flexor digitorum superficialis (FDS) insertion is a relative contraindication to replantation. The aim of this study is to conduct a systematic review on replantation of these injuries to synthesize best available evidence on outcomes. This review was registered in PROSPERO under registration number CRD42021277305. A MEDLINE, CENTRAL, and EMBASE databases search yielded 1536 studies. Primary clinical studies on single digit replantation and functional outcome with at least 10 cases were included. Data on revision amputation and replantation distal to the FDS were collected as comparators. Data extracted included demographics, type of digit, level of injury, secondary surgeries, duration of sick leave, survival, function, and patient-reported outcomes. All studies were assessed using the Risk of Bias In Non-randomized Studies of Intervention (ROBINS-I) tool and data synthesis was completed using RevMan and Microsoft Excel. Six studies representing 182 replanted single digits that were amputated proximal to the FDS insertion were included. The average PIPJ motion of replanted single digits was 50° in those amputated proximal to the FDS insertion compared to 82.5 in those amputated distal to the FDS. The average Michigan Hand Questionnaire (MHQ) score was 84.78 in replantation group versus 76.81 in the amputation group which was statistically significant (p< .00001). Mean Disability of Arm, Shoulder, and Hand Questionnaire (DASH) score was 12 in replantation group compared to 18.5 in amputation group, however this was not statistically significant (p= .17). Few studies exist on outcomes of single digit replantations proximal to FDS insertion. Although range of motion is inferior in the replant group, this has increased since initial studies were performed, and patient satisfaction and patient reported outcomes are high. This is promising evidence for achieving reasonable outcomes in replantation of single digits amputated proximal to the FDS. Level III.

Non-contact optical in-vivo sensing of cilia motion by analyzing speckle patterns

Cilia motion is an indicator of pathological-ciliary function, however current diagnosis relies on biopsies. In this paper, we propose an innovative approach for sensing cilia motility. We present an endoscopic configuration for measuring the motion frequency of cilia in the nasal cavity. The technique is based on temporal tracking of the reflected spatial distribution of defocused speckle patterns while illuminating the cilia with a laser. The setup splits the optical signal into two channels; One imaging channel is for the visualization of the physician and another is, defocusing channel, to capture the speckles. We present in-vivo measurements from healthy subjects undergoing endoscopic examination. We found an average motion frequency of around 7.3 Hz and 9.8 Hz in the antero-posterior nasal mucus (an area rich in cilia), which matches the normal cilia range of 7–16 Hz. Quantitative and precise measurements of cilia vibration will optimize the diagnosis and treatment of pathological-ciliary function. This method is simple, minimally invasive, inexpensive, and promising to distinguish between normal and ciliary dysfunction.

On analyzing GNSS displacement field variability of Taiwan: Hierarchical Agglomerative Clustering based on Dynamic Time Warping technique

We investigate the feasibility of using the Dynamic Time Warping (DTW) technique to cluster continuous GNSS displacements in Taiwan. Using the DTW distance as the measure for waveform similarity, we combine the DTW method with the Hierarchical Agglomerative Clustering (HAC) algorithm. This is in contrast to the conventional clustering approach that uses the Euclidean distance, considering the average long-term crustal motion, but inherently neglects full-waveform temporal variations. Here we apply the DTW-based HAC algorithm adopting DTW distance as the waveform similarity measure on 11 years worth of 3-D displacement data from 115 continuous GNSS network stations in Taiwan. We demonstrate the efficacy of the DTW-based HAC method in distinguishing the GNSS spatiotemporal variabilities that are consistent with the known, complex tectonic behavior of the region. An open-source Python package has been developed and made available to perform the HAC analysis.

Hindfoot Motion Analysis by Subtalar Compensation and Ankle Osteoarthritis Stage using a 3D Multi- Segment Foot Model

Category: Hindfoot Introduction/Purpose: Biomechanics of the hindfoot in ankle osteoarthritis (OA) have not yet fully understood. We aimed to identify hindfoot motions by gait analysis using multi-segment foot model (MFM) according to the stage of ankle OA or hindfoot alignment determined by the presence of subtalar compensation. Methods: We retrospectively reviewed the medical records, simple radiographs, and gait MFM data from 54 ankles which admitted to our hospital for the treatment of advanced ankle OA. Spatiotemporal gait parameters and 3-dimensional motions of hindfoot segment were analyzed according to sex, age, body mass index, the Takakura classification, and the presence of subtalar compensation. Results: As a result, all spatiotemporal gait parameters showed no significant difference according to the presence of subtalar compensation and the stage of ankle OA. With regard to the relationship between hindfoot segmental motion and the stage of ankle OA, only normalized step width was significantly different from each other (p value=0.028). Average motion of hindfoot (decompensation versus compensation) showed no significant difference in sagittal and transverse plane. In coronal movement of hindfoot, there were collapsed curves in both groups, which had constant significant difference. In comparison of 3a, 3b, and 4 stages of Takakura, more advanced 3b stages of ankle OA had the smaller sagittal range of motion compared to 3a (p value=0.028). Coronal movement of hindfoot in Takakura 3a/3b/4 all showed relatively flat pattern. Conclusion: In conclusion, spatiotemporal parameters were not affected by the alignment state of the heel resulted from subtalar compensation. Sagittal range of hindfoot motion decreased in the advanced ankle OA. Coronal movement of subtalar joint in ankle OA, once it was disrupted, showed no change regardless of the stage of ankle OA or compensation state of the hindfoot.

Adaptive margins for online adaptive radiotherapy

Objective. In online adaptive radiotherapy a new plan is generated every fraction based on the organ and clinical target volume (CTV) delineations of that fraction. This allows for a planning target volume margin that does not need to be constant over the whole course of treatment, as is the case in conventional radiotherapy. This work aims to introduce an approach to update the margins each fraction based on the per-patient treatment history and explore the potential benefits of such adaptive margins. Approach. We introduce a novel methodology to implement adaptive margins, isotropic and anisotropic, during a treatment course based on the accumulated dose to the CTV. We then simulate treatment histories for treatments delivered in up to 20 fractions using various choices for the standard deviations of the systematic and random errors and homogeneous and inhomogeneous dose distributions. The treatment-averaged adaptive margin was compared to standard constant margins. The change in the minimum dose delivered to the CTV was compared on a patient and a population level. All simulations were performed within the van Herk approach and its known limitations. Main results. The population mean treatment-averaged margins are down to 70% and 55% of the corresponding necessary constant margins for the isotropic and anisotropic approach. The reduction increases with longer fractionation schemes and an inhomogeneous target dose distribution. Most of the benefit can be attributed to the elimination of the effective systematic error over the course of treatment. Interpatient differences in treatment-averaged margins were largest for the isotropic margins. For the 10% of patients that would receive a lower than prescribed dose to the CTV this minimum dose to the CTV is increased using the adaptive margin approaches. Significance. Adaptive margins can allow to reduce margins in most patients without compromising patients with greater than average target motion.