Motion Variations Research Articles

Encoding Time-Series Ground Motions as Images for Convolutional Neural Networks-Based Seismic Damage Evaluation

Traditional methods for seismic damage evaluation require manual extractions of intensity measures (IMs) to properly represent the record-to-record variation of ground motions. Contemporary methods such as convolutional neural networks (CNNs) for time series classification and seismic damage evaluation face a challenge in training due to a huge task of ground-motion image encoding. Presently, no consensus has been reached on the understanding of the most suitable encoding technique and image size (width × height × channel) for CNN-based seismic damage evaluation. In this study, we propose and develop a new image encoding technique based on time-series segmentation (TS) to transform acceleration (A), velocity (V), and displacement (D) ground motion records into a three-channel AVD image of the ground motion event with a pre-defined size of width × height. The proposed TS technique is compared with two time-series image encoding techniques, namely recurrence plot (RP) and wavelet transform (WT). The CNN trained through the TS technique is also compared with the IM-based machine learning approach. The CNN-based feature extraction has comparable classification performance to the IM-based approach. WT 1,000 × 100 results in the highest 79.5% accuracy in classification while TS 100 × 100 with a classification accuracy of 76.8% is most computationally efficient. Both the WT 1,000 × 100 and TS 100 × 100 three-channel AVD image encoding methods are promising for future studies of CNN-based seismic damage evaluation.

Application of mineral liberation analysis (MLA) for investigations of grain size distribution in submarine density flow deposits

Textural and structural features of submarine mass density flow sediments are a record of depositional flow evolution and hydrodynamics. Record of changes in such flow movement are difficult or impossible to detect, especially in fine sediments, without quantitative grain size analysis. This study shows an automated measurement system of mineral liberation analysis MLA applied for the first time to grain size distribution. The analysis concerns heavy minerals extracted from very fine- and fine-grained sandstones of the Cergowa Beds (Lower Oligocene) in the Polish and Slovak Outer Carpathians, which macroscopically show unclear textural trends and represent deposits of steady and uniform turbidity currents, possibly initiated by hyperpycnal effluents. The MLA analysis showed that the tested material represents sediments deposited by flows with developing turbulence. Simultaneously, the study verified that a turbulence damping contributes to size-density sorting during transport and demonstrated that maximum rather than average grain size is controlled by flow concentration, therefore reflects flow hydrodynamics. Besides, MLA measurements recognised variations in flow motion recorded by three types of grain-size breaks: (i) in high-density flow when capacity-controlled conditions are changing so that high energy flow erodes the previously deposited material; (ii) at a sharp interface between high-concentration basal layer and the overriding flow with lower concentration, and (iii) at a transition between low- and high-density flows during deposition of the Bouma interval Tb or between Tb and Tc. The MLA test study appears to be promising because this method increases objectivity of large amount of data collection, therefore provides significant statistical representation. Besides, this automated system reduces human errors, bias and tedious manual analyses, thus opening new perspectives in analysis of detrital sediments and interpretation of depositional processes.

PanoMan: Sparse Localized Components–based Model for Full Human Motions

Parameterizing Variations of human shapes and motions is a long-standing problem in computer graphics and vision. Most of the existing methods only deal with a specific kind of motion, such as body poses, facial expressions, or hand gestures. We propose PanoMan (sParse locAlized compoNents based mOdel for full huMAn motioNs) to handle shape variation and full-motion across body, face, and hand in a unified framework. Like previous approaches, we factor shape variation into principal components to obtain a human shape space that approximates the shape of arbitrary identity. We then analyze sparse localized components in terms of relative edge length and dihedral angle to capture full motions of body poses, facial expressions, and hand gestures. The final piece of our model is a multilayer perceptron (MLP) that fits the residual between the ground truth and the aforementioned two-level approximation. As an application, we employ the discrete-shell deformation to drive the model to fit sparse constraints such as joint positions and surface feature points. We thoroughly evaluate PanoMan on body, face, and hand motion benchmarks as well as scanned data. The existing skinning-based techniques suffer from joint collapsing when encountering twisting motion of joints. Experiments show that PanoMan can capture all kinds of full human motions with high quality and is easier than the state-of-the-art models in recovering poses with wide joint twisting and complex hand gestures.

Output Regulation of Linear Stochastic Systems

We address the output regulation problem for a general class of linear stochastic systems. Specifically, we formulate and solve the ideal full-information and output-feedback problems, obtaining perfect, but non-causal, asymptotic regulation. A characterisation of the problem solvability is deduced. We point out that the ideal problems cannot be solved in practice because they unrealistically require that the Brownian motion affecting the system is available for feedback. Drawing from the ideal solution, we formulate and solve approximate versions of the full-information and output-feedback problems, which do not yield perfect asymptotic tracking but can be solved in a realistic scenario. These solutions rely on two key ideas: first we introduce a discrete-time a-posteriori estimator of the variations of the Brownian motion obtained causally by sampling the system state or output; second we introduce a hybrid state observer and a hybrid regulator scheme which employ the estimated Brownian variations. The approximate solution tends to the ideal as the sampling period tends to zero. The proposed theory is validated by the regulation of a circuit subject to electromagnetic noise.

Microscopic understanding of particle-matrix interaction in magnetic hybrid materials by element-specific spectroscopy

Abstract Mössbauer spectroscopy is a well-known technique to study complex magnetic structures, due to its sensitivity to electronic and magnetic interactions of the probed nucleus with its electronic surrounding. It has also been applied to the emerging fields of magnetic hybrid materials as well as to ferrofluids, as information on the magnetic alignment and the velocity of the probed nucleus, i.e. of the particle it is embedded in, can be inferred from the spectra in addition to the above-mentioned quantities. Considering the wide range of preparation methods and sample properties, including fluids, particle powders, sintered pellets, polymer matrices and viscoelastic hydrogels, a considerable advantage of Mössbauer spectroscopy is the usage of γ-photons. This allows measurements on opaque samples, for which optical experiments are usually not feasible, also making the technique relatively independent of specific sample geometries or preparation. Using iron oxide nanoparticles in glycerol solution as an exemplary material here, the variety of system parameters simultaneously accessible via Mössbauer spectroscopy can be demonstrated: Spectra recorded for particles of different sizes provided information on the particles’ Brownian dynamics, including the effect of the shell thickness on their hydrodynamic diameter, the presence (or absence) and ballpark frequency of Néel superspin relaxation as well as the particles’ average magnetic orientation in external magnetic fields. For single-core particles, this resulted in the observation of standard Langevin-type alignment behavior. Mössbauer spectra additionally provide information on the absolute degree of spin alignment, also allowing the determination of the degree of surface spin canting, which limits the maximum magnetization of ferrofluid samples. Analyzing the alignment behavior of agglomerated particles for comparison, we found a completely different trend, in which spin alignment was further hindered by the competition of easy magnetic directions. More complex particle dynamics are observed when going from ferrofluids to hybrid materials, where the particle mobility and alignability depends not only on the particles’ shape and material, but also on the matrices’ inner structure and the acting force-transfer mechanism between particles and the surrounding medium. In ferrohydrogels for example, particle mobility in terms of Mössbauer spectroscopy was probed for different crosslinker concentrations, resulting in widely different mesh-sizes of the polymer network and different degrees of freedom. While a decrease in particle dynamics is clearly visible in Mössbauer spectroscopy upon rising crosslinker density, complementary AC-susceptometry experiments indicated no Brownian motion on the expected timescales. This apparent contradiction could, however, be explained by the different timescales of the experiments, probing either the relatively free Brownian motion on ultrashort timescales or the more bound state preventing extensive particle motion by interaction with the trapping mesh walls in the millisecond regime. However, it should also be considered that the effect of the surroundings on particle rotation in AC-susceptometry may also differ from the variation in translational motion, probed by Mössbauer spectroscopy. Being sensitive mainly to translational motion also results in a wide range of particles to be accessible for studies via Mössbauer spectroscopy, including larger agglomerates embedded in polymers, intended for remote-controlled heating. Despite the agglomerates’ wide distribution in effective diameters, information on particle motion was found to be in good agreement with AC-susceptometry experiments at ultralow frequencies in and above the polymer melting region, while additionally giving insight into Néel relaxation of the individual nanoparticles and their magnetic structure.

Track and Teach: Identifying Key Movement Patterns in Endoscopic Transurethral Enucleation of the Prostate

Purpose: We evaluated a system for noninvasive quantitative motion tracking to recognize differences in the movement pattern of experienced surgeons and beginners. Since performing endoscopic procedures requires extensive training, and tissue damage due to disruptive movements with sudden acceleration is possible, the learning curve for beginners is of clinical relevance. Steepening this curve may improve patient outcome. Materials and Methods: We used a commercial gyroscope sensor with a wireless data link, which was attached to the resectoscope handle (RH). After recording, orientation was retrieved by application of the calculated rotation matrices to the RH vector relative to the sensor under the boundary condition of rotational movement around and quasi-constant distance to the pivot point at pelvic floor level. Data alignment, normalization, interpolation, and analysis were performed in custom software scripts. Results: Experienced surgeons and beginners were recorded in n = 36 and n = 14 holmium laser enucleation of the prostate (HoLEP), respectively. Prostate size, patient age, and recorded procedure duration were comparable. Mean lever angle of the individual normalized motion patterns was considerably lower (19.28 ± 0.54° [SEM]) in the advanced than in the beginners’ group (24.52 ± 1.00°; p = 0.0001). Further parameters such as velocity and motion variation demonstrated additional differences between both groups. Conclusions: We demonstrate the feasibility of motion tracking in HoLEP. Pronounced differences exist between different stages of surgeon experience with this procedure. The method can easily be adopted to aide young surgeons in resectoscope handling and identification of improvable motion patterns. Damage to the pelvic floor and surrounding tissue may thus be reduced.

Challenges in the definition of input motions for forensic ground-response analysis in the near-source region

This article scrutinizes the determination of input motions for forensic ground-response analysis in the near-source region, based on recorded surface ground motions at strong-motion station sites, from the same event. The first part of the article draws upon observed ground motions from the 22 February 2011 6.2 Mw Christchurch earthquake to discuss key challenges of the problem associated with the strong spatial variation of ground motion in the near-source region. Effects from the complexity of the rupture, propagation of seismic waves through complex geological structures, and site characteristics are explored. It is argued that, because of the strongly varying source-path “signature” on near-source ground motions, “reference” input motions for ground-response analysis must be specific to, and have similar signature characteristics (be “compatible”) with, the target site which is subject to the analysis. The second part of the article presents a four-step procedure for the derivation of site-specific input motions involving (1) determination of the reference layer where the input motion is to be applied in the analysis, (2) record selection considering the appropriateness of the recording station site for deconvolution and its compatibility with the target site, (3) deconvolution of the selected record to remove local site effects from the recorded ground motion, and (4) scaling of the deconvolved motion to account for differences in the source-to-site distance between the recording station and the target site. As part of the proposed procedure, a novel (amplitude-duration) scaling method is presented. Results from one-dimensional (1D) effective-stress analysis of two target Christchurch sites using input motions from the proposed procedure are used to critically evaluate the procedure and discuss essential requirements for its successful application.

A 3D cine-MRI acquisition technique and image analysis framework to quantify bowel motion demonstrated in gynecological cancer patients.

PurposeMagnetic resonance imaging (MRI) is increasingly used in radiation oncology for target delineation and radiotherapy treatment planning, for example, in patients with gynecological cancers. As a consequence of pelvic radiotherapy, a part of the bowel is irradiated, yielding risk of bowel toxicity. Existing dose‐effect models predicting bowel toxicity are inconclusive and bowel motion might be an important confounding factor. The exact motion of the bowel and dosimetric effects of its motion are yet uncharted territories in radiotherapy. In diagnostic radiology methods on the acquisition of dynamic MRI sequences were developed for bowel motility visualization and quantification. Our study aim was to develop an imaging technique based on three‐dimensional (3D) cine‐MRI to visualize and quantify bowel motion and demonstrate it in a cohort of gynecological cancer patients.MethodsWe developed an MRI acquisition suitable for 3D bowel motion quantification, namely a balanced turbo field echo sequence (TE = 1.39 ms, TR = 2.8 ms), acquiring images in 3.7 s (dynamic) with a 1.25 × 1.25 × 2.5 mm3 resolution, yielding a field of view of 200 × 200 × 125 mm3. These MRI bowel motion sequences were acquired in 22 gynecological patients. During a 10‐min scan, 160 dynamics were acquired. Subsequent dynamics were deformably registered using a B‐spline transformation model, resulting in 159 3D deformation vector fields (DVFs) per MRI set. From the 159 DVFs, the average vector length was calculated per voxel to generate bowel motion maps. Quality assurance was performed on all 159 DVFs per MRI, using the Jacobian Determinant and the Harmonic Energy as deformable image registration error metrics. In order to quantify bowel motion, we introduced the concept of cumulative motion–volume histogram (MVH) of the bowel bag volume. Finally, interpatient variation of bowel motion was analyzed using the MVH parameters M10%, M50%, and M90%. The M10%/M50%/M90% represents the minimum bowel motion per frame of 10%/50%/90% of the bowel bag volume.ResultsThe motion maps resulted in a visualization of areas with small and large movements within the bowel bag. After applying quality assurance, the M10%, M50%, and M90% were 4.4 (range 2.2–7.6) mm, 2.2 (range 0.9–4.1) mm, and 0.5 (range 0.2–1.4) mm per frame, on average over all patients, respectively.ConclusionWe have developed a method to visualize and quantify 3D bowel motion with the use of bowel motion specific MRI sequences in 22 gynecological cancer patients. This 3D cine‐MRI‐based quantification tool and the concept of MVHs can be used in further studies to determine the effect of radiotherapy on bowel motion and to find the relation with dose effects to the small bowel. In addition, the developed technique can be a very interesting application for bowel motility assessment in diagnostic radiology.

Nonlinear numerical assessment of the seismic response of hillside RC buildings

Major damage has been reported in hilly areas after major earthquakes, primarily because of two special conditions: the variation in the seismic ground motion due to the inclined ground surface and the irregularities caused by a stepped base level in the structure. The aim of this study is to evaluate possible differences in the responses of Chilean hillside buildings through numerical linear-elastic and nonlinear analyses. In the first step, a set of response-spectrum analyses were performed on four simplified 2D structures with mean base inclination angles of 0°, 15°, 30°, and 45°. The structures were designed to comply with Chilean seismic codes and standards, and the primary response parameters were compared. To assess the seismic performance of the buildings, nonlinear static (pushover) and dynamic (time-history) analyses were performed with SeismoStruct software. Pushover analyses were used to compare the nonlinear response at the maximum roof displacement and the damage patterns. Time-history analyses were performed to assess the nonlinear dynamic response of the structures subjected to seismic ground motions modified by topographic effects. To consider the topographic modification, acceleration records were obtained from numerical models of soil, which were calculated using the rock acceleration record of the Mw 8.0 1985 Chilean earthquake. Minor differences in the structure responses (roof displacements and maximum element forces and moments) were caused by the topographic effects in the seismic input motion, with the highly predominant ones being the differences caused by the step-back configuration at the base of the structures. High concentrations of shear forces in short walls were observed, corresponding to the walls located in the upper zone of the foundation system. The response of the structures with higher angles was observed to be more prone to fragile failures due to the accumulation of shear forces. Even though hillside buildings gain stiffness in the lower stories, resulting in lower design roof displacement, maximum roof displacements for nonlinear time-history analyses remained very close for all the models that were primarily affected by the drifts of the lower stories. Additionally, vertical parasitic accelerations were considered for half the time-history analyses performed here. The vertical component seems to considerably modify the axial load levels in the shear walls on all stories.

Steam flow excited vibration and dynamic characteristics of seal in different rotor whirling motion

A multi-frequency conical whirl model was established to investigate the influence of different rotor whirling motion on seal steam flow excited vibration and dynamic characteristics. The simulation method of rotor motion was improved to adapt the ultra-supercritical steam turbine, in which the whirling motion and rotational motion were decomposed by user-defined function (UDF). The seal steam flow excited vibration and dynamic characteristics of parallel whirl motion, semi and full conical whirl motion were present. The influences of different rotor motion were analyzed via pressure waveform. The dynamic coefficients have the obvious variation in semi and full conical whirl motion. The expansion profile of seal cavity caused by conical whirl motion makes the fluctuation range of circumferential pressure great.

Application of discrete cosine transform to assess the effect of tumor motion variations on the definition of ITV in lung and liver SBRT.

To use Discrete Cosine Transform to include tumor motion variations on ITV definition of SBRT patients. Data from 66 patients was collected. 2D planar fluoroscopy images (FI) were available for 54 patients. Daily CBCT projections (CBCTp) from 29 patients were employed to measure interfraction amplitude variability. Systematic amplitude variations were obtained from 17 patients with data from both FI and CBCTp. Tumor motion curves obtained from FI were characterized with a Cosine model (CM), based on cosine functions to the power of 2, 4 or 6, and DCT. Performance of both models was evaluated by means of R2 coefficient and by comparing their results on Internal Target Volume (ITV) margins against those calculated from original tumor motion curves. Amplitude variations from CBCTp, as well as estimations of baseline shift variations were added to the DCT model to account for their effect on ITV margins. DCT replicated tumor motion curves with a mean R2 values for all patients of 0.86, 0.91 and 0.96 for the lateral (LAT), anterior-posterior (AP) and cranio-caudal (CC) directions respectively. CM yielded worst results, with R2 values of 0.64, 0.61 and 0.74 in the three directions. Interfraction amplitude variation increased ITV margins by a 9%, while baseline shift variability implied a 40% and 80-100% increase for normalized values of baseline shift of 0.2 and 0.4 respectively. Probability distribution functions of tumor positions can be successfully characterized with DCT. This permits to include tumor motion variablilities obtained from patient population into patient specific ITVs.

Small Island Effects in DYNAMO and Their Impact on Large-Scale Budget Analyses

AbstractDuring the Dynamics of the MJO (DYNAMO) field campaign, radiosonde launches were regularly conducted from three small islands/atolls (Malé and Gan, Maldives, and Diego Garcia, British Indian Ocean Territory) as part of a large-scale sounding network. Comparison of island upsondes with nearby and near-contemporaneous dropsondes over the ocean provides evidence for the magnitude and scope of the islands’ influence on the surrounding atmosphere and on the island upsonde profiles. The island’s impact on the upsonde data is most prominent in the lowest 200 m. Noting that the vertical gradients of temperature, moisture, and winds over the ocean are generally constant in the lowest 0.5 km of dropsondes, a simple procedure was constructed to adjust the upsonde profiles in the lowest few hundred meters to resemble the atmospheric structures over the open ocean. This procedure was applied to the soundings from the three islands mentioned above for the October–December 2011 period of DYNAMO. As a result of this procedure, the adjusted diurnal cycle amplitude of surface temperature is reduced fivefold, resembling that over the ocean, and low-level wind speeds are increased in ~90% of the island soundings. Examination of the impact of these sounding adjustments shows that dynamical and budget fields are primarily affected by adjustments to the wind field, whereas convective parameters are sensitive to the adjustments in thermodynamic fields. Although the impact of the adjustments is generally small (on the order of a few percent), intraseasonal wind regime changes result in some systematic variations in divergence and vertical motion over the sounding arrays.

The constancy of the holistic processing of unfamiliar faces: Evidence from the study-test consistency effect and the within-person motion and viewpoint invariance

It has been well documented that static face processing is holistic. Faces contain variant (e.g., motion, viewpoint) and invariant (race, sex) features. However, little research has focused on whether holistic face representations are tolerant of within-person variations. The present study thus investigated whether holistic face representations of faces are tolerant of within-person motion and viewpoint variations by manipulating study-test consistency using a complete composite paradigm. Participants were shown two faces sequentially and were asked to judge whether the faces' top halves were identical or different. The first face was a static face or a dynamic face rotated in depth at 30°, 60°, and 90°. The second face was either a different front-view static face (Experiment 1a, study-test inconsistent) or identical to the first face (Experiment 1b, study-test consistent). In Experiment 2, study-test consistency was manipulated within subjects, and inverted faces were included. Our results show that study-test consistency significantly enhanced the holistic processing of upright and inverted faces; this study-test consistency effect and holistic processing were not modulated by motion and viewpoint changes via depth rotation. Interestingly, we found holistic processing for moving study-test consistent inverted faces, but not for static inverted faces. What these results tell us about the nature of holistic face representation is discussed in depth with respect to earlier and current theories on face processing.

Action recognition using kinematics posture feature on 3D skeleton joint locations

Action recognition is a very widely explored research area in computer vision and related fields. We propose Kinematics Posture Feature (KPF) extraction from 3D joint positions based on skeleton data for improving the performance of action recognition. In this approach, we consider the skeleton 3D joints as kinematics sensors. We propose Linear Joint Position Feature (LJPF) and Angular Joint Position Feature (AJPF) based on 3D linear joint positions and angles between bone segments. We then combine these two kinematics features for each video frame for each action to create the KPF feature sets. These feature sets encode the variation of motion in the temporal domain as if each body joint represents kinematics position and orientation sensors. In the next stage, we process the extracted KPF feature descriptor by using a low pass filter, and segment them by using sliding windows with optimized length. This concept resembles the approach of processing kinematics sensor data. From the segmented windows, we compute the Position-based Statistical Feature (PSF). These features consist of temporal domain statistical features (e.g., mean, standard deviation, variance, etc.). These statistical features encode the variation of postures (i.e., joint positions and angles) across the video frames. For performing classification, we explore Support Vector Machine (Linear), RNN, CNNRNN, and ConvRNN model. The proposed PSF feature sets demonstrate prominent performance in both statistical machine learning- and deep learning-based models. For evaluation, we explore five benchmark datasets namely UTKinect-Action3D, Kinect Activity Recognition Dataset (KARD), MSR 3D Action Pairs, Florence 3D, and Office Activity Dataset (OAD). To prevent overfitting, we consider the leave-one-subject-out framework as the experimental setup and perform 10-fold cross-validation. Our approach outperforms several existing methods in these benchmark datasets and achieves very promising classification performance.

Designing self-oscillating matter

Designing self-oscillating matter

The capacity analysis of dynamic positioning for semi-submersible vessel

In this paper, the Dynamic Position model (DP) of semi-submersible vessel was established in Ariane system based on static analysis and standards, to obtain DP capability polar plot under different failure pattern. Through the time-domain simulation, PID control theory and Kalman filtering method were used in DP accuracy analysis. Analysis results, such as ship motion, DP accuracy and propeller variation, could be provided for safety and reliability check in engineering practice.

Real-time measurement of ICD lead motion during stereotactic body radiotherapy of ventricular tachycardia.

Here we aimed to evaluate the respiratory and cardiac-induced motion of a ICD lead used as surrogate in the heart during stereotactic body radiotherapy (SBRT) of ventricular tachycardia (VT). Data provides insight regarding motion and motion variations during treatment. We analyzed the log files of surrogate motion during SBRT of ventricular tachycardia performed in 20 patients. Evaluated parameters included the ICD lead motion amplitudes; intrafraction amplitude variability; correlation error between the ICD lead and external markers; and margin expansion in the superior-inferior (SI), latero-lateral (LL), and anterior-posterior (AP) directions to cover 90% or 95% of all amplitudes. In the SI, LL, and AP directions, respectively, the mean motion amplitudes were 5.0 ± 2.6, 3.4. ± 1.9, and 3.1 ± 1.6 mm. The mean intrafraction amplitude variability was 2.6 ± 0.9, 1.9 ± 1.3, and 1.6 ± 0.8 mm in the SI, LL, and AP directions, respectively. The margins required to cover 95% of ICD lead motion amplitudes were 9.5, 6.7, and 5.5 mm in the SI, LL, and AP directions, respectively. The mean correlation error was 2.2 ± 0.9 mm. Data from online tracking indicated motion irregularities and correlation errors, necessitating an increased CTV-PTV margin of 3 mm. In 35% of cases, the motion variability exceeded 3 mm in one or more directions. We recommend verifying the correlation between CTV and surrogate individually for every patient, especially for targets with posterobasal localization where we observed the highest difference between the lead and CTV motion.

Reconfigurable Physical Unclonable Function Based on Spin-Orbit Torque Induced Chiral Domain Wall Motion

A reliable design of physical unclonable function (PUF) based on spin-orbit torque (SOT) induced domain wall (DW) motion has been proposed and experimentally demonstrated. Magnetic DWs are nucleated and propagate in Ta/CoFeB/MgO heterostructures in which their device-to-device variation enables the PUF, while cycle-to-cycle variation in DW motion enables the reconfigurable design. Furthermore, field-free SOT switching has been observed in the chiral domain wall likely caused by the large Dzyaloshinskii-Moriya interaction (DMI) effect. The proposed DW motion based anti-counterfeiting device shows good promises as a CMOS-compatible PUF for hardware security.

Asymmetrically distorted 3D video quality assessment: From the motion variation to perceived quality

The two-stage framework has been widely used in objective image/video quality assessment (IQA/VQA) methods, which includes local quality measurement and global quality pooling. Most of the existing IQA/VQA methods dedicate to local quality degradation modeling. Nevertheless, the significant pooling strategies are often neglected, especially in the quality assessment methods for asymmetrically distorted 3D video sequences. In this paper, motivated by the fact that the perceptual visual information might be affected by the visual masking due to motion suppression, a novel pooling strategy is proposed for visual quality assessment of asymmetrically distorted 3D video sequences by considering the motion variation-based perceptual visual information (MVPVI). In specific, to extract valuable visual information of video sequences, the proposed method computes the motion energy information (MEI) and edge energy information (EEI) by quantifying the frame difference map and the gradient map, respectively. Furthermore, in order to simulate the phenomenon of motion suppression in local motion scenes, where the perceptual information of low-attentional regions might be neglected by the human visual system (HVS), the proposed method first employs the coefficient of variation (CV) to determine the type of motion (local or global) in consecutive frames. Then, the perceptual visual information of the two cases is quantified. Finally, to simulate the role of HVS as an optimal information extractor, the estimated perceptual visual information of each single-view video sequence is used as the weighting factor for the quality pooling of left and right-view video sequences. Extensive comparison experiments conducted on Waterloo-IVC 3D video quality databases demonstrate that the proposed pooling strategy outperforms other relevant pooling strategies, and it achieves better performance than state-of-the-art 3D-IQA/VQA methods when combined with 2D-IQA/VQA methods.

Molecular dynamics, residue network analysis, and cross-correlation matrix to characterize the deleterious missense mutations in GALE causing galactosemia III.

Epimerase-deficiency galactosemia (EDG) is caused by mutations in the UDP-galactose 4'-epimerase enzyme, encoded by gene GALE. Catalyzing the last reaction in the Leloir pathway, UDP-galactose-4-epimerase catalyzes the interconversion of UDP-galactose and UDP-glucose. This study aimed to use in-depth computational strategies to prioritize the pathogenic missense mutations in GALE protein and investigate the systemic behavior, conformational spaces, atomic motions, and cross-correlation matrix of the GALE protein. We searched four databases (dbSNP, ClinVar, UniProt, and HGMD) and major biological literature databases (PubMed, Science Direct, and Google Scholar), for missense mutations that are associated with EDG patients, our search yielded 190 missense mutations. We applied a systematic computational prediction pipeline, including pathogenicity, stability, biochemical, conservational, protein residue contacts, and structural analysis, to predict the pathogenicity of these mutations. We found three mutations (p.K161N, p.R239W, and p.G302D) with a severe phenotype in patients with EDG that correlated with our computational prediction analysis; thus, they were selected for further structural and simulation analyses to compute the flexibility and stability of the mutant GALE proteins. The three mutants were subjected to molecular dynamics simulation (MDS) with native protein for 200 ns using GROMACS. The MDS demonstrated that these mutations affected the beta-sheets and helical region that are responsible for the catalytic activity; subsequently, affects the stability and flexibility of the mutant proteins along with a decrease and more deviations in compactness when compared to that of a native. Also, three mutations created major variations in the combined atomic motions of the catalytic and C-terminal regions. The network analysis of the residues in the native and three mutant protein structures showed disturbed residue contacts occurred owing to the missense mutations. Our findings help to understand the structural behavior of a protein owing to mutation and are intended to serve as a platform for prioritizing mutations, which could be potential targets for drug discovery and development of targeted therapeutics.