Angular Modes Research Articles

Selective intra prediction in HEVC planar and angular modes for efficient near-lossless video compression

In the lossless mode of HEVC (high efficiency video coding), the coding gains of sample-based prediction algorithms are always better than the conventional block-based predictions within the HEVC anchor. Both block based and sample-based prediction strategies select the best prediction mode for the current prediction unit (PU), on the basis of a cost function evaluated at the PU level. Hence, the selected prediction mode for a PU may not be generating the best prediction at the pixel level. If the selection of the best prediction mode can be performed at the pixel level, the accuracy of prediction can be increased significantly. In this work, we propose two selective intra prediction strategies (SIP) which select the best prediction mode from the block-based and sample-based predictions at the pixel level. In the proposed SIP-A algorithm the SIP strategy is applied to only angular prediction modes while the combined SIP algorithm (SIP-C) employs the SIP strategy in both the angular and planar prediction modes. The proposed SIP-C algorithm enhances the performance of the current state of the art SIP algorithm in the literature by introducing better prediction strategies for both angular and planar predictions of HEVC intra prediction. To avoid the enormous overhead required to convey the choice of prediction from the encoder to the decoder, SIP algorithms utilise the least significant bit (LSB) piggybacking strategy. The experimental results provide significant improvements in coding gain and run time for the proposed near-lossless SIP algorithms.

Conformational analysis and vibrational spectroscopic studies of tetraethoxysilane and its hydrolysis products: A DFT prediction

The density functional theory was used to carry out a systematic investigation about the conformational and vibrational analyses of tetraethoxysilane (TEOS) and its hydrolysis products (Si(OCH2CH3)4−n(OH)n, n = 1–4). All possible potential energy curve (PEC) scans were performed in different symmetry point groups, D2d, S4, C2v and Cs, for the fully hydrolyzed product of TEOS, Si(OH)4. The main results indicate clear differences in the spectral profile of each molecular system, which can be used for monitoring the sol-gel processes at the hydrolysis stage. The most significative changes take place in 750–1000 cm−1, where mainly the νasSiO asymmetric stretching and δSiOH angular deformation modes are localized. A significant coupling between νasSiO and δSiOH is observed for the computed spectra of Si(OH)4 in gas-phase, with more pronounced effect for S4 ad D2d symmetries. For the partial hydrolysis products of TEOS (Si(OCH2CH3)4−n(OH)n, n = 1–3) this coupling is also present and it is evidenced by the fact that both vibrational bands in 750–900 cm−1 (δSiOH) and 900–1000 cm−1 (νSiO) show a great contribution of the SiO bond length displacements as much as of the SiOH bond angle changes.

Компенсация погрешностей и учет нелинейности колебаний вибрационного кольцевого микрогироскопа в режиме датчика угловой скорости

Компенсация погрешностей и учет нелинейности колебаний вибрационного кольцевого микрогироскопа в режиме датчика угловой скорости

Vortex type oscillations in a multi-component plasma

Abstract Owing to the fact that the helical wave structures with azimuthal phase dependence can exist and propagate longitudinally in a plasma, a kind of linearized ion-acoustic vortices or phonon modes are studied with orbital angular momentum in an unmagnetized uniform multi-component plasma. Laguerre-Gaussian (LG) type density and potential perturbations are considered to solve the wave equation in paraxial approximation. The solutions determine finite orbital angular momentum states associated with the ion motion giving rise to phonon modes exhibited as vortex-like (twisted) ion-acoustic waves. The electric field energy and angular momentum density are calculated and the effects of the twist due to azimuthal phase components of density and potential profiles are elaborated. The role of density balance and other parameters like radial and angular mode numbers and phase angle are highlighted in the numerical analysis. The relevance of the work with plasma motion in the environment of twisting fields is discussed.

Factors effecting hamstrings to quadriceps peak torque ratio in volleyball players

The aim of this study was to analyze of hamstring to quadriceps peak torque ratio (H:Q) measured in isokinetic testing with respect to different angular velocities (60, 180, 300°/s), gender, dominant side and mode of contraction (concentric, eccentric) in volleyball players. Twenty male and ten female healthy volleyball players participated in this study. An independent t-test was used to compare the differences between gender. One-way analysis of variance test was conducted to test for differences by effecting factors. There was a statistically significant difference between dominant and non-dominant side in H:Q ratio at 300°/s in males (p<0.05). There was no statistically significant difference between dominant and non-dominant side in H:Q ratio between female and male volleyball players (p>0.05). There was no statistically significant difference between at 60-180-300°/s velocities by Hconc:Qconc contractions and at 60°/s by Hconc:Qecc contractions for male and female’s peak torques in dominant side (p>0.05). There was a statistically significant difference between at 60°/s by Hconc:Qconc and Hconc:Qecc contractions for male and female’s peak torques in dominant side (p<0.05). There was a statistically significant difference H:Q ratio obtained by concentric contraction between at 60-300°/s and 180-300°/s velocities (p<0.05), whereas there was no statistically significant difference between 60-180°/s in male and female’s peak torques in dominant side (p>0.05). It was found in our study that H:Q ratio increases with increasing angular velocity. The findings of the present study indicated that angular velocity, type of contraction and leg dominance influence isokinetic strength profiles of male and female, consequently, muscular balance that is H:Q at the knee. This implies that isokinetic concentric knee strength plays more role in high intensity contractions and has more effect at high velocities of contraction in maximal performance.

Anomalous radial and angular strain relaxation around dilute p-, isoelectronic-, and n-type dopants in Si crystal

Doping is widely applied in yielding desirable properties and functions in silicon technology; thus, fully understanding the relaxation mechanism for lattice-mismatch strain is of fundamental importance. Here we systematically study the local lattice distortion near dilute IIIA-, IVA-, and VA-group substitutional dopants in Si crystal using density functional theory, and anomalous radial and angular strain relaxation modes are first revealed. Both the nearest-neighbor (NN) bond-distances and the tetrahedral bond-angles are found to exhibit completely opposite dependence on the electronic configurations for the low Z (Z<26) and high Z (Z>26) dopants. More surprisingly, negative and positive angular shifts for the second NN twelve Si2 atoms are unveiled surrounding the p- and n-type dopants, respectively. While electron localization function shows that the doped hole and electron are highly localized near the dopants, hence being responsible for the abnormal angular shifts, a universal radial strain relaxation mechanism dominated by a competition of the Coulomb interactions among the ion-core, bond-charge, and the localized hole or electron is also proposed. These findings may prove to be instrumental in precise design of silicon-based solotronics.

The clustering of galaxies in the completed SDSS-III Baryon Oscillation Spectroscopic Survey: baryon acoustic oscillations in the Fourier space

We analyse the Baryon Acoustic Oscillation (BAO) signal of the final Baryon Oscillation Spectroscopic Survey (BOSS) data release (DR12). Our analysis is performed in Fourier-space, using the power spectrum monopole and quadrupole. The dataset includes $1\,198\,006$ galaxies over the redshift range $0.2 < z < 0.75$. We divide this dataset into three (overlapping) redshift bins with the effective redshifts $\zeff = 0.38$, $0.51$ and $0.61$. We demonstrate the reliability of our analysis pipeline using N-body simulations as well as $\sim 1000$ MultiDark-Patchy mock catalogues, which mimic the BOSS-DR12 target selection. We apply density field reconstruction to enhance the BAO signal-to-noise ratio. By including the power spectrum quadrupole we can separate the line-of-sight and angular modes, which allows us to constrain the angular diameter distance $D_A(z)$ and the Hubble parameter $H(z)$ separately. We obtain two independent $1.6\%$ and $1.5\%$ constraints on $D_A(z)$ and $2.9\%$ and $2.3\%$ constraints on $H(z)$ for the low ($\zeff=0.38$) and high ($\zeff=0.61$) redshift bin, respectively. We obtain two independent $1\%$ and $0.9\%$ constraints on the angular averaged distance $D_V(z)$, when ignoring the Alcock-Paczynski effect. The detection significance of the BAO signal is of the order of $8\sigma$ (post-reconstruction) for each of the three redshift bins. Our results are in good agreement with the Planck prediction within $\Lambda$CDM. This paper is part of a set that analyses the final galaxy clustering dataset from BOSS. The measurements and likelihoods presented here are combined with others in~\citet{Alam2016} to produce the final cosmological constraints from BOSS.

Table top surface plasmon resonance measurement system for efficient urea biosensing using ZnO thin film matrix.

The present report addresses the application of surface plasmon resonance (SPR) phenomenon for urea sensing. The former promises a high sensitivity, label-free detection, and real-time information by monitoring the refractive index change at the metal–dielectric interface. In the present report, a highly sensitive urea biosensor has been developed by integrating a ZnO thin film matrix with the SPR technique. Kretschmann configuration has been used to excite the surface plasmon (SP) modes at the ZnO–metal (gold) interface using an indigeneously developed table top SPR measurement setup. Urease (Urs), the urea-specific enzyme, has been immobilized on the surface of ZnO thin film by physical adsorption technique. The SPR reflectance curves were recorded for the prism/Au/ZnO/Urs system in angular interrogation mode with phosphate-buffered saline (PBS) solution as the liquid media. The SPR resonance angle is found to be shifted toward a lower angle from 49.1 to 42.0 deg with an increase in the urea concentration (0 to 300 mg/dl) in the PBS solution. The developed sensor (prism/Au/ZnO/Urs) is found to be highly sensitive [sensitivity=0.039 deg/(mg/dl) or 203 deg/RIU] with detection accuracy of 0.045(deg)(−1).

Angular default mode network connectivity across working memory load.

Initially identified during no-task, baseline conditions, it has now been suggested that the default mode network (DMN) engages during a variety of working memory paradigms through its flexible interactions with other large-scale brain networks. Nevertheless, its contribution to whole-brain connectivity dynamics across increasing working memory load has not been explicitly assessed. The aim of our study was to determine which DMN hubs relate to working memory task performance during an fMRI-based n-back paradigm with parametric increases in difficulty. Using a voxel-wise metric, termed the intrinsic connectivity contrast (ICC), we found that the bilateral angular gyri (core DMN hubs) displayed the greatest change in global connectivity across three levels of n-back task load. Subsequent seed-based functional connectivity analysis revealed that the angular DMN regions robustly interact with other large-scale brain networks, suggesting a potential involvement in the global integration of information. Further support for this hypothesis comes from the significant correlations we found between angular gyri connectivity and reaction times to correct responses. The implication from our study is that the DMN is actively involved during the n-back task and thus plays an important role related to working memory, with its core angular regions contributing to the changes in global brain connectivity in response to increasing environmental demands. Hum Brain Mapp 38:41-52, 2017. © 2016 Wiley Periodicals, Inc.

Atmospheric integrated water vapour measured by IR and MW techniques at the Peterhof site (Saint Petersburg, Russia)

ABSTRACTRegular comparison of different systems for monitoring atmospheric integrated water vapour (IWV) is part of their testing and validation protocol. We compared coincident measurements of IWV over Saint Petersburg (Russia) from ground-based Fourier-transform spectrometer Bruker IFS 125 HR (FTIR) and microwave radiometer RPG-HATPRO (MW) at the Peterhof site between March 2013 and June 2015. This study is a contribution towards global efforts to make such inter-comparisons at various ground-based sites. Since FTIR measures solar radiance, the vast majority of coincident pairs correspond to the spring and summer seasons. The numbers of measurements in the dry season (from October to April) and in the wet season (from May to September) are almost identical, comprising 616 and 638 pairs, respectively. MW and FTIR data sets demonstrate a high level of agreement: the mean relative difference between MW and FTIR data is less than 3% (0.3 mm), with standard deviation from the means of about 4% (0.4 mm). Notwithstanding the short distance between both instruments (150 m), they can monitor different air masses: MW is a zenith-viewing instrument whereas FTIR follows the sun. We analysed the FTIR observation fields under different solar zenith and azimuth angles, taking into account the location of the Peterhof site between the Gulf of Finland and rural suburbs of Saint Petersburg. Although in general MW measurements slightly overestimated IWV in comparison with the FTIR data, we detected several episodes when FTIR gave higher values than MW. These episodes relate to the FTIR observations directed at the coastal region with more humid air than that above the measurement site. We may conclude at this stage of our investigations that the spatial inhomogeneity of humidity fields in the atmosphere causes the most significant differences between the two data sets. Detailed analysis of variation in spatial IWV, e.g. using a MW radiometer in angular scanning mode, is an issue for future research.

Self-assembling peptide hydrogels immobilized on silicon surfaces

The hydrogels of self-assembling ionic complementary peptides have collected in the scientific community increasing consensus as mimetics of the extracellular matrix that can offer 3D supports for cell growth or be vehicles for the delivery of stem cells or drugs. Such scaffolds have also been proposed as bone substitutes for small defects as they promote beneficial effects on human osteoblasts. In this context, our research deals with the introduction of a layer of self-assembling peptides on a silicon surface by covalent anchoring and subsequent physisorption.In this work, we present a spectroscopic investigation of the proposed bioactive scaffolds, carried out by surface-sensitive spectroscopic techniques such as XPS (X-ray photoelectron spectroscopy) and RAIRS (Reflection Absorption Infrared Spectroscopy) and by state-of-the-art synchrotron radiation methodologies such as angle dependent NEXAFS (Near Edge X-ray Absorption Fine Structure). XPS studies confirmed the change in the surface composition in agreement with the proposed enrichments, and led to assess the self-assembling peptide chemical stability. NEXAFS spectra, collected in angular dependent mode at the N K-edge, allowed to investigate the self-assembling behavior of the macromolecules, as well as to determine their molecular orientation on the substrate. Furthermore, Infrared Spectroscopy measurements demonstrated that the peptide maintains its secondary structure (β-sheet anti-parallel) after deposition on the silicon surface. The complementary information acquired by means of XPS, NEXAFS and RAIRS lead to hypothesize a “layer-by-layer” arrangement of the immobilized peptides, giving rise to an ordered 3D nanostructure.

Sensitive optical biosensor based on surface plasmon resonance using ZnO/Au bilayered structure

The present article represents the preparation of highly sensitive optical biosensor using an indigenously assembled table top Surface plasmon resonance (SPR) technique. Surface plasmon modes have been excited at the ZnO-gold interface exploiting Kretschmann configuration. RF-magnetron sputtering has been utilised to deposit ZnO thin films further used for the immobilization of specific enzyme GOx by physical adsorption technique. The SPR reflectance curves were recorded for the GOx/ZnO/Au/prism system in angular interrogation mode in Phosphate buffer saline (PBS) solution by varying analyte (glucose) concentration from 0mg/dl to 300mg/dl. The transient variation in the intensity of reflectance (i.e. response) at fixed SPR resonance angle for increasing concentration of glucose is also reported. The prepared sensor exhibits enhanced response (0.75 for 25mg/dl) with high specificity and good linearity beyond the physiological range indicating the realization of an efficient optical biosensor.

Fast and efficient intra mode decision for HEVC, based on dual-tree complex wavelet

The new video coding standard, High Efficiency Video Coding (HEVC) uses up to 33 angular intra modes to achieve better coding efficiency in intra coding. While larger number of modes results in a significant increase in coding efficiency than its predecessor H.264/AVC, it leads to much more complexity. To reduce this complexity, this paper proposes a novel method based on the dual-tree complex wavelet Transform (CWT). As CWT is effectively capable of representing edges in various directions, it is used to estimate the best intra angular mode in each coding block. The encoder then only analyzes a few modes around the best estimated mode. The experimental results show that searching only six modes around the estimated mode (estimated mode?±?3) plus DC and planar can predict the best mode in almost 80 % of the times. In fact the remaining unpredicted blocks have such unspecified behavior that even their random selections do not have any side effects. With all-intra configuration, searching with this method among the estimated mode?±?3 and DC and planar can improve the intra frame coding time by up to 4---10 times faster and can save the total encoding time over 32 %, while causing less than 0.4 % increase in bitrate and preserving the quality.

Influence analysis of secondary O-ring seals in dynamic behavior of spiral groove gas face seals

The current research on secondary O-ring seals used in mechanical seals has begun to focus on their dynamic properties. However, detailed analysis of the dynamic properties of O-ring seals in spiral groove gas face seals is lacking. In particular a transient study and a difference analysis of steady-state and transient performance are imperative. In this paper, a case study is performed to gauge the effect of secondary O-ring seals on the dynamic behavior (steady-state performance and transient performance) of face seals. A numerical finite element method (FEM) model is developed for the dynamic analysis of spiral groove gas face seals with a flexibly mounted stator in the axial and angular modes. The rotor tilt angle, static stator tilt angle and O-ring damping are selected to investigate the effect of O-ring seals on face seals during stable running operation. The results show that the angular factor can be ignored to save time in the simulation under small damping or undamped conditions. However, large O-ring damping has an enormous effect on the angular phase difference of mated rings, affecting the steady-state performance of face seals and largely increasing the possibility of face contact that reduces the service life of face seals. A pressure drop fluctuation is carried out to analyze the effect of O-ring seals on the transient performance of face seals. The results show that face seals could remain stable without support stiffness and O-ring damping during normal stable operation but may enter a large-leakage state when confronting instantaneous fluctuations. The oscillation-amplitude shortening effect of O-ring damping on the axial mode is much greater than that on the angular modes and O-ring damping prefers to cater for axial motion at the cost of angular motion. This research proposes a detailed dynamic-property study of O-ring seals in spiral groove gas face seals, to assist in the design of face seals.

Low complexity depth map intra prediction mode decision algorithm for 3D-HEVC

The presented 3D video coding extension of High Efficiency Video Coding (3D-HEVC) was developed for multiview video plus depth (MVD) format. MVD is depth-enhanced 3D video format that uses a few views to synthesize more immediate virtual views with depth map. In the original 3D-HEVC encoder, as a novel tool Depth Modeling Modes (DMM) is added into intra prediction mode candidate list, which aims at improving as much coding efficiency as possible for 3D-HEVC. However, this promotion leads to extremely complicated computation simultaneously which prevents 3D-HEVC encoder from real-time application. In this paper, we propose a low complexity depth map intra prediction mode decision algorithm, including fast angular modes decision algorithm and early skipping DMM decision algorithm. The basic idea of the proposed algorithm is to predict the current depth block intra prediction mode based on depth map texture feature and early skip DMM decision. Experimental results demonstrate that the proposed low complexity algorithm can achieve 38% coding time reduction with just 1.00% bitrate augment on average under “all-intra” case compared to the original 3D-HEVC encoder.

Fast intra mode decision algorithm based on texture orientation detection in HEVC

The High Efficiency Video Coding is the new video coding standard, which obtains over 50% bit rate savings compared with H.264/AVC for the same perceptual quality. Intra-prediction coding in HEVC achieves high coding performance at the expense of high computational complexity, due to the high density of angular prediction modes, among other new features. This work presents a novel texture orientation detection algorithm by computing the local directional variance along a set of co-lines with rational slopes in the discrete lattice Λ. According with the dominant gradient detected, a reduced set of directional candidate modes is selected to be further checked by the rate-distortion optimization stage. The experimental results demonstrate the proposed algorithm can achieve a 30% computational complexity reduction compared with the HEVC reference model, with a negligible bit rate increase of 0.4%, and quality losses lower 0.03dB. Comparisons with similar state-of-the-art works show the proposed approach achieves the best trade-off between complexity reduction and rate-distortion.

Local topological charge analysis of electromagnetic vortex beam based on empirical mode decomposition.

The topological charge of an electromagnetic vortex beam depends on its wavefront helicity. For mixed vortex beams composed of several different coaxial vortices, it is significant to investigate the local topological charges. Fourier transform based methods are restrained by the uncertainty principle and cannot achieve high angular resolution and mode resolution simultaneously. In this paper, an analysis method for local topological charges of vortex beams is presented based on the empirical mode decomposition (EMD). From EMD, the intrinsic mode functions (IMFs) can be obtained to construct the bases of the electromagnetic wave, and each local topological charge can be respectively defined. With this method the local value achieves high resolution of both azimuth angle and topological charge, meanwhile the amplitudes of each orbital angular momentum (OAM) modes are presented as well. The simulation and experimental results confirm the validity of the EMD based method.

Optical Properties and Instrumental Performance of thin Noble Metal (Cu, Au, Ag) Films Near the Surface Plasmon Resonance

Surface plasmon resonance sensors are routinely employed optical instruments for biochemical research and suited for medical diagnostics. Optical properties and associated instrumental performance of nanometer thin sputter deposited Au, Ag and Cu films at the metal-water interface are reported and compared with theoretical predictions. Prominent optical SP-excitations persist in very thin metal films on BK7 glass substrates and metal film thickness of approximately 40-50nm. Thin Au films are long-term chemically stable in neutral aqueous buffer solution. Cu and Ag films tend to deteriorate and oxidize over longer time period, especially when exposed to solutions with pH>7. Achievable sensor detectivities in the wavelength and angular interrogation modes are compared. The influence of surface oxidation on the irreversible adsorption of a common protein is also reported.

A Prism-based Polymeric Surface Plasmon Resonance Biochip for Angular and Spectral Modes

A prism-based polymeric biochip (called PPBIO), that allows surface plasmon resonance sensing in both angular and spectral or wavelength interrogation modes, was designed and constructed. It is formed from high quality polymer materials, which uses injection molding method to the high volume manufacture of prisms. Two molds have been manufactured with three and four cavities and a comparison is also presented. Experimental tests were conducted and the results indicate a reduction in the mechanical stresses and birefringence. Eventually, our proposal is a good candidate for point-of-care diagnosis, like is extensively investigated for tropical diseases.

Cosmology Large Angular Scale Surveyor (CLASS) Focal Plane Development

The Cosmology Large Angular Scale Surveyor (CLASS) will measure the polarization of the Cosmic Microwave Background to search for and characterize the polarized signature of inflation. CLASS will operate from the Atacama Desert and observe $$\sim $$ 70 % of the sky. A variable-delay polarization modulator provides modulation of the polarization at $$\sim $$ 10 Hz to suppress the 1/f noise of the atmosphere and enable the measurement of the large angular scale polarization modes. The measurement of the inflationary signal across angular scales that spans both the recombination and reionization features allows a test of the predicted shape of the polarized angular power spectra in addition to a measurement of the energy scale of inflation. CLASS is an array of telescopes covering frequencies of 38, 93, 148, and 217 GHz. These frequencies straddle the foreground minimum and thus allow the extraction of foregrounds from the primordial signal. Each focal plane contains feedhorn-coupled transition-edge sensors that simultaneously detect two orthogonal linear polarizations. The use of single-crystal silicon as the dielectric for the on-chip transmission lines enables both high efficiency and uniformity in fabrication. Integrated band definition has been implemented that both controls the bandpass of the single-mode transmission on the chip and prevents stray light from coupling to the detectors.