Recording Of Waves Research Articles

Extreme learning machine approach on heart abnormalities identification in ECG images

Heart abnormalities are atypical heart conditions that can lead to chronic heart disease. Heart abnormalities can be severe if not treated directly due to the crucial function of the heart as the blood circulation center. Heart abnormalities cannot be seen with the naked eye so it requires the recording of a heartbeat wave or electrocardiogram (EKG) for the disease to be detected. Therefore, a strategy that uses image processing and artificial neural networks to detect anomalies in the heart is strongly advocated. The proposed methods for feature extraction and identification are Invariant Moments and Extreme Learning Machine respectively. The testing procedure for this research employed a total of 386 ECG images as training data. and 44 ECG images for test data, and the heart condition was classified into 4 classes, namely Atrial Fibrillation, T-Wave, ST-Segment, and normal heart conditions. The test was carried out using 3 choices of extreme learning machine activation functions, namely sigmoidal, sine and hard-lim. The test also applied the parameter of hidden neurons in which amounting to 10, 30, 50, 100 and 500. The system accuracy in identifying heart abnormalities achieved 95.45% by the application of the sigmoid function with the total number of hidden neurons equal to 500.

Coherent Noise (Ground roll) Consideration: Local Wave-field Decomposition (LWD) Based Approaches to Suppression

There is always a signal and a noise component in seismic data. Noise can be defined as any recorded energy that tampers with the desired signal of interest. Although it might be difficult to separate signal from noise due to the variety of noise kinds, effective noise suppression is crucial for high-quality imaging. Surface waves or ground roll are a prominent source-generated coherent noise in exploration seismology. Ground roll contains little to no information about the deeper subsurface as it moves laterally through the earth’s near surface. The low-frequency contents and strong amplitudes of these arrivals often mask recordings of body waves reflected by deeper subsurface targets. This discussion paper will describe ground rolls, a significant form of seismic coherent noise, as well as their unique characteristics, how they appear on acquired seismic data, the significance of suppressing them in seismic processing applications, and an examination of local wave-field decomposition (LWD) techniques and their applications.

Does VS30 reflect seismic amplification? Observations from the West Bohemia Seismic Network

The present study addresses verification of average seismic shear-wave velocity from the surface to a depth of 30 m (VS30) as a suitable proxy for a seismic amplification. For this purpose, we used instrumentally homogeneous and spatially dense seismic network WEBNET (West Bohemia Seismic Network), designed to monitor an intraplate earthquake swarm activity in the West Bohemia/Vogtland region (Czech Republic/Germany). Using a Multichannel analysis of surface waves (MASW) shear-wave velocity models and parameters VS30 and H800 (depth of Vs > 800 m/s) were obtained at 17 WEBNET sites. VS30 were compared with (i) H800 and (ii) determined bedrock densities. To understand the relation between VS30 and site amplification, VS30 values were correlated with amplitudes of two earthquakes: (1) Mw 6.4 Petrinja, Croatia (12/2020) and (2) Mw 4.2 SE of Vienna, Austria (03/2021) both recorded by the WEBNET. The correlation analysis examined four categories of seismic waves in nine frequency windows and described the relation between amplification and VS30 using newly defined regression model. The results show that for the regression model, the frequency window with the highest correlation is in the 1–3 Hz range, and this dependence is statistically best observed in the full wave record. The amplification generally decreases with increasing VS30. However, a large scatter in amplification within Eurocode 8 category B is observed. Based on the observations a new general approach is put forward to finely indicate the relation between amplification and VS30 and the use of other site proxies is discussed.

A Creativity Monitoring Device (CMD) for New Insight into the Brain Mechanisms of Artistic, Scientific and Engineering Creative Acts

This paper introduces the basic design of a novel neuroscientific device named Creativity Monitoring Device, CMD, able to provide new insights into the brain mechanisms of artistic, scientific and engineering creative acts. The novelty of the device is threefold. First, it allows the artifact-free recording of association cortical EEG waves during such creative acts as painting artistic visions, composing music, running novel experiments in a laboratory or working on an engineering invention. Second, it allows the synchronous monitoring of the sounds and visual events in the environment of such actions along with the artist’s, scientist’s or engineer’s verbal and non-verbal interactions with this environment and his or her own notes on the engaged creative phase. Third, it allows the offline analysis of the synchronously collected EEG and audio-visual data with the new method of dynamic neurocombinatorics, which can reveal at 2 msec accuracy the relationships between the recorded objects of 5 sets: (1) the spatial occurrence codes of the recorded association cortical EEG waves; (2) the complexity codes of each of the recorded 0.2 - 200 Hz EEG waves; (3) the codes of the synchronously recorded environmental events including those of the subject’s verbal and non-verbal interactions with this environment; (4) the subject’s own dictated notes identifying the phase of the engaged creative act, and (5) the time-course of these continuously recorded objects within each of the indicated sets over the entire, at least 10-hour, creativity monitoring period. Thus, CMD studies should reveal the key electrical brain changes underlying the initiation, maintenance and termination of creative acts and should show the similarities and differences between artistic, scientific and engineering creativities.

Model validation and applications of wave and current forecasts from the Hong Kong Observatory's Operational Marine Forecasting System

The Hong Kong Observatory has been running an Operational Marine Forecasting System (OMFS) adapted from the Regional Ocean Modelling System (ROMS) coupled with the WaveWatch III and SWAN wave models to provide wave, current and sea temperature forecasts up to 144 h twice a day since December 2021. To facilitate users’ interpretation of model forecasts of significant wave height and current speed in coastal predictions and open seas which are of particular significance in high wind situations, model forecasts were validated against moored buoy observations and wave recorder measurements near the shores of Hong Kong and drifting buoy data over the South China Sea, as well as Mercator Ocean model reanalysis in 2022. The validation results showed that the wave forecasts generally agreed well with the buoy observations with coefficient of determination (R2) of around 0.7 and root-mean-square error (RMSE) of less than 0.2 m up to 72 h ahead. The R2 for sea current forecasts ranged between 0.4 and 0.6, and the RMSE was around 8 to 11 cm/s in near shores up to T + 144 forecast hours. Validation against drifting buoy demonstrated that the trend of current forecasts generally agreed well with the measurements. RMSE of surface current forecasts over open seas ranged from 19 cm/s for 24-hour forecast to around 30 cm/s for 144-hour forecast when compared against Mercator Ocean reanalysis. Results from the current downscaling approach could serve as a benchmark reference for HKO to enhance OMFS in the future. In this paper, applications of model forecasts in the provision of marine weather services in Hong Kong are also introduced.

Non-invasive assessment of stroke volume and cardiovascular parameters based on peripheral pressure waveform.

Cardiovascular diseases are the leading cause of death globally, making the development of non-invasive and simple-to-use tools that bring insights into the state of the cardiovascular system of utmost importance. We investigated the possibility of using peripheral pulse wave recordings to estimate stroke volume (SV) and subject-specific parameters describing the selected properties of the cardiovascular system. Peripheral pressure waveforms were recorded in the radial artery using applanation tonometry (SphygmoCor) in 35 hemodialysis (HD) patients and 14 healthy subjects. The pressure waveforms were then used to estimate subject-specific parameters of a mathematical model of pulse wave propagation coupled with the elastance-based model of the left ventricle. Bioimpedance cardiography measurements (PhysioFlow) were performed to validate the model-estimated SV. Mean absolute percentage error between the simulated and measured pressure waveforms was 4.0% and 2.8% for the HD and control group, respectively. We obtained a moderate correlation between the model-estimated and bioimpedance-based SV (r = 0.57, p<0.05, and r = 0.58, p<0.001, for the control group and HD patients, respectively). We also observed a correlation between the estimated end-systolic elastance of the left ventricle and the peripheral systolic pressure in both HD patients (r = 0.84, p<0.001) and the control group (r = 0.70, p<0.01). These preliminary results suggest that, after additional validation and possibly further refinement to increase accuracy, the proposed methodology could support non-invasive assessment of stroke volume and selected heart function parameters and vascular properties. Importantly, the proposed method could be potentially implemented in the existing devices measuring peripheral pressure waveforms.

Registration of the atmospheric effect of the Hunga Tonga volcano eruption

The paper presents the results of recording of acoustic waves, caused by the Hunga Tonga volcano eruption in the South Pacific Ocean on January 15, 2022, in Eastern Siberia at a distance of about 11230 km from the eruption. The received acoustic signal is interpreted as a set of atmospheric waves in a wide range of oscillations. The structure of the signal is similar to signals from the previously known powerful sources: the thermonuclear explosion on Novaya Zemlya in 1961 and the explosion of the Tunguska meteorite in 1908. The acoustic signal was preceded by three trains of low-frequency damped oscillations. We assume that these three trains of oscillations are associated with three important stages in the Hunga Tonga volcano eruption: 1) destruction of Tonga island and formation of an underwater caldera; 2) release of hot magma from the caldera to the ocean surface and release of a large volume of superheated steam into the atmosphere 3) formation of a layered structure from a mixture of superheated steam, ash, and tephra on the ocean surface and formation of an eruptive convective column. Successive phases of the eruption might have contributed to the excitation of acoustic vibrations in a wide range of periods including Lamb waves, internal gravity waves (IGW), and infrasound. We compare the structure of the acoustic signal received in Siberia at a distance of more than 11000 km from the volcano and that of the acoustic signal recorded in Alaska at a distance of more than 9300 km. Using the solution of the linearized Korteweg — de Vries equation, we estimate the energy released during the volcanic eruption.

О регистрации атмосферного эффекта извержения вулкана Хунга-Тонга

The paper presents the results of recording of acoustic waves, caused by the Hunga Tonga volcano eruption in the South Pacific Ocean on January 15, 2022, in Eastern Siberia at a distance of about 11230 km from the eruption. The received acoustic signal is interpreted as a set of atmospheric waves in a wide range of oscillations. The structure of the signal is similar to signals from the previously known powerful sources: the thermonuclear explosion on Novaya Zemlya in 1961 and the explosion of the Tunguska meteorite in 1908. The acoustic signal was preceded by three trains of low-frequency damped oscillations. We assume that these three trains of oscillations are associated with three important stages in the Hunga Tonga volcano eruption: 1) destruction of Tonga island and formation of an underwater caldera; 2) release of hot magma from the caldera to the ocean surface and release of a large volume of superheated steam into the atmosphere 3) formation of a layered structure from a mixture of superheated steam, ash, and tephra on the ocean surface and formation of an eruptive convective column. Successive phases of the eruption might have contributed to the excitation of acoustic vibrations in a wide range of periods including Lamb waves, internal gravity waves (IGW), and infrasound. We compare the structure of the acoustic signal received in Siberia at a distance of more than 11000 km from the volcano and that of the acoustic signal recorded in Alaska at a distance of more than 9300 km. Using the solution of the linearized Korteweg — de Vries equation, we estimate the energy released during the volcanic eruption.

Estimates of longshore sediment transport rates along Macumba and Recreio-Barra da Tijuca sandy beaches (Rio de Janeiro, southeastern Brazil)

Due to the complex nature of coastal dynamics, several models were developed to estimate longshore sediment transport (LST) rates. The Coastal Engineering Research Center (CERC), Kamphuis, and Bayram models are among the most used and were applied to three east–west oriented sandy urban beaches from Rio de Janeiro (southeastern Brazil): Macumba, Recreio, and Barra da Tijuca. The wave record from oceanographic buoys and the WaveWatch III (WW3) model were used to identify fairweather periods and increased storminess between 2016 and 2018. Eastwards, median sediment grain-size grades from coarse to medium sand, and is associated with decreasing beach slopes in the same direction. The magnitude of the estimated LST rates varied significantly between the models (Δ ≈ 1,000 m3/day, p < 0.001), although the time-averaged LST rates obtained from the four models indicate eastward transport. The four models identified areas of convergence and divergence of sediment transport with increasing rates to the east. The modeling results may support effective coastal management initiatives when integrated with topographic profiles, numerical modeling, satellite imagery, and historical information.

Pulse rate variability and health-related quality of life assessment with the Short Form-8 Japanese version in the general Japanese population

We aimed to investigate the association between pulse rate variability (PRV) and health-related quality of life (HRQOL) in the general population. A cross-sectional study was conducted with 5908 Japanese men and women aged 30–79 years. PRV was assessed at rest using 5-min recordings of pulse waves with a photoplethysmographic signal from a fingertip sensor, and the time and frequency domains of PRV were determined. HRQOL was assessed with the Short Form-8 (SF-8) Japanese version, and poor HRQOL was defined as an SF-8 sub-scale score < 50. A test for nonlinear trends was performed with the generalized additive model with a smoothing spline adjusted for confounders. The lowest multivariable-adjusted odds ratios for poor physical component score were found in those who had second or third quartile levels of standard deviation of normal-to-normal intervals (SDNN) and root mean square of successive difference (RMSSD), and high-frequency (HF) power and trended slightly upward in the higher levels. PRV-derived parameters were nonlinearly associated with poor physical component scores. In conclusion, reduced PRV-derived SDNN, RMSSD and HF power were associated with poor HRQOL in the domain of physical function. Higher levels of these parameters did not necessarily translate into better HRQOL.

Ocean Coupling Limits Rupture Velocity of Fastest Observed Ice Shelf Rift Propagation Event

AbstractThe Antarctic ice sheet is buttressed by floating ice shelves that calve icebergs along large fractures called rifts. Despite the significant influence exerted by rifting on ice shelf geometry and buttressing, the scarcity of in situ observations of rift propagation contributes considerable uncertainty to understanding rift dynamics. Here, we report the first‐ever seismic recording of a multiple‐kilometer rift propagation event. Remote sensing and seismic recordings reveal that a rift in the Pine Island Glacier Ice Shelf extended 10.53 km at a speed of 35.1 m/s, the fastest known ice fracture at this scale. We simulate ocean‐coupled rift propagation and find that the dynamics of water flow within the rift limit the propagation rate, resulting in rupture two orders of magnitude slower than typically predicted for brittle fracture. Using seismic recordings of the elastic waves generated during rift propagation, we estimate that ocean water flows into the rift at a rate of at least 2,300 m3/s during rift propagation and causes mixing in the subshelf cavity. Our observations support the hypotheses that large ice shelf rift propagation events are brittle, hydrodynamically limited, and exhibit sensitive coupling with the surrounding ocean.

Волны в морской акватории вблизи мыса Свободный (юго-восточная часть о. Сахалин)

A study of wave processes near Cape Svobodny on the south-eastern coast of the island Sakhalin using autonomous wave recorders and a weather station has been performed. Analysis of five-month data of sea level and temperature, atmospheric pressure and wind speed revealed that there are no significant peaks for wind and infragravity (IG) waves in the wave period range 2–600 s, and the wave energy is lower at the point protected by Cape Svobodny. During storms, there is an increase in the energy of IG waves. Waves detected at periods of 14.2 seconds, 3.62 minutes, and 8.85 minutes are related to swell and edge waves propagating seaward. For explanation of short waves, the Longuet-Higgins and Stewart theory was used which describes the dispersion of swell in the surf zone and the formation of free waves. Edge waves were analyzed using the Lamb model and the Bessel function of the first kind of zero order. Modelling of wave processes propagating shoreward revealed the presence of IG waves with periods of 20–110 seconds and edge waves with periods of 4.27–7.63 minutes, confirmed by the dispersion relation for Stokes waves on a sloping bottom. Sea water temperature fluctuations of more than 7 °C with periods of 3–100 minutes affect the propagation of waves with periods longer than 3 minutes, destroying the edge and leaky waves. Analysis of wind wave characteristics showed no significant wave processes, including wind waves, in the 2–20 second period range. The maximum wave height was observed during prolonged southern winds associated with a cyclone. This study is important for understanding wave processes in this area, aiding in predicting their behaviour and impact on the coastline.

Field observations of Hurricane Ian’s wave and surge impact in the areas of Fort Myers Beach and Sanibel Island, USA

On September 18, Category 4 Hurricane Ian made landfall near Fort Myers Beach and Sanibel Island, two barrier islands on the northern Gulf of Mexico. In this paper, we present a novel set of observations from a post-event High Water Mark field survey as well as wavelet analysis of in-situ wave data. We also present a qualitative overview of some erosive effects and infrastructure damage. Measured peak surge elevations exceed 5 m, and wave plus surge elevations exceed 6.0 m (NAVD88). High Water Mark observations are consistent within the expected range produced by numerical hindcast models. A wavelet analysis, from one of the few wave records available during the storm, demonstrates the presence of long-period basin mode waves at a 40-min period. The 40-min wave appeared on the wave record before the storm surge, and the peak of this motion also occurred before the peak of the surge. In addition, the wavelet analysis reveals the presence of infragravity wave energy (periods between 30 s and 20 min). Together, these intermediate and long-period waves add over 40 cm to the total water level at peak energy. The measured field data shows a rapidly decreasing surge elevation within the first 300 m from the pre-storm shoreline, and we observe no statistically meaningful attenuation difference between the highly developed shoreline of Fort Myers and the more vegetated shoreline of Sanibel Island. However, the structural survey team observed more infrastructure damage in Fort Myers than Sanibel Island.

FLAYERS IN THE PLANETS ATMOSPHERE

Planets of the Solar System or exoplanets with atmospheres are complicated to investigate because of the absence of sufficiently intense energy fluxes reflected by their atmospheres. At a sufficiently high brightness of the neighboring star, the atmosphere of the exoplanet gives the absorption spectra of some molecules with a high dissociation potential. If the star's surface temperature is low enough and its activity is low, then the presence of thunderstorm activity in the planet's atmosphere can make it possible to identify it. We show the processes that lead to the formation of flare spectra in the γ- and optical ranges and ways to identify them. It is important to note that current discharges initiate intense nuclear transformations with the formation of proton-rich C11, N13, and O15 nuclei. The spectrum of such a medium is specific and different from the spectra formed by the neighboring star. The statistical irregularity of the frequency of thunderstorms and the variety of conditions in the atmospheres of planets makes it possible to study them due to their illumination in the optical part of the spectrum. It is shown that the integrated optical flow and the detailed γ-spectrum make it possible to trace the time evolution of the lightning head current cord and obtain quantitative values of the current strength. Such fluctuations of the current give changes in the magnetic field of the filament, comparable with the value and even greater than the intrinsic magnetic fields of the planets. To carry out the proposed research, M. Doikov developed a multichannel spectrograph consisting of a γ- and optical spectrometer, a highly sensitive magnetometer, and a radio wave recorder. Its design is discussed in his report. We also note here that the calculations make it possible to determine the statistical parameter of time signals, the operating modes of the equipment, and the selection of the necessary nodes for designing the final working layout of the multichannel spectrometer. The value of the choice of observation site is indicated. In mountainous areas, these are heights of the order of a kilometer. In this case, the devices are near lightning.

Automatic Extraction of Surface Wave Dispersion Curves Using Unsupervised Learning and High‐Resolution Tau‐p Transform

AbstractDispersion curves for surface wave recordings are required input for many surface wave inversion methods to image subsurface shear wave velocity distribution, while the conventional extraction of dispersion curves requires significant amount of human interaction. This step impedes efficiency enhancement of surface wave analysis and its automation. In this paper, we present an unsupervised learning scheme to achieve efficient automatic picking of dispersion curves of the fundamental mode for surface wave gathers. This scheme is composed of four major steps: computing a frequency velocity(f‐v) spectrum for the surface wave gather using a high‐resolution Tau‐p transform improved by the iteratively shrinkage Thresholding algorithm (ISTA) algorithm, generating clusters points along the dispersion energy in the f‐v spectrum via a weighted Kmeans algorithm, filtering these cluster points by principal component analysis (PCA) and Local Outlier Factor (LOF) algorithms to remove the erroneous clusters, and fitting the remaining clusters to form the dispersion curve. Tests with synthetic and field noisy surface wave recordings demonstrated the effectiveness of this approach and its potential in automatic processing of noisy surface wave data sets.

Effect Analysis on Field Acquisition Parameters of Surface Wave Survey - Case Study on The Gobi Desert Field

In this paper, the Gobi Desert landform is used as a test site to analysis the results on surface wave survey. The body wave exploration methods are used to determined velocity structure of the site as a reference standard firstly. Subsequently, different acquisition parameters for surface wave are tested. After comparing the results, the optimal parameters are selected by using the surface wave multi-channel analysis method (MASW). Meanwhile, several theoretical equations for estimating minimum offset, optimum offset, geophone spread length, and resolution of dispersion are demonstrated as the guidelines to organize the real-world data acquisition. Finally, the selected optimal parameters are applied to the data acquisition of total 69 surface wave recorders. The final two-dimensional inversion profile is in good agreement with the known background. It means the method of MASW is feasible in geological surveys on Gobi Desert landform.

Storm Franz: Societal and energy impacts in northwest Europe on 11–12 January 2007

Abstract. January 2007 was a bad storm month for much of central and northern Europe with a series of extratropical cyclones bringing high winds and precipitation to highly populated areas between Ireland and Russia. Although Storm Kyrill on 18–19 January 2007 was the most serious for its infrastructure damage and insurance costs, Storm Franz from the preceding week on 11–12 January 2007 was actually more serious for its maritime impacts in western Europe. This contribution takes a closer look at Storm Franz with an overview of its wind field and its impact on energy infrastructure, transportation networks and building damage. Maritime casualties are reviewed with respect to met-ocean conditions. The storm was notable for a series of wave-related accidents off southeast Ireland, the English Channel, and German Bight. An analysis is carried out on water level recorders around the North Sea to assess the storm surge and short period oscillations that may reveal harbour seiches or meteotsunamis. The results are compared with wave recorders, which had a fairly good coverage across the North Sea in 2007. The issue of wave damage to offshore infrastructure was highlighted in events associated with Storm Britta on 31 October–1 November 2006. Offshore wind energy in northwest Europe was in a growth phase during this time, and there were questions about the extreme met-ocean conditions that could be expected in the 20 year lifetime of an offshore wind turbine.

Spectrum Analysis of Sound Wave Recordings with Dolphinear type DE200 Based on Distance and Frequency Variations in Mahakam River Using Audacity Software

Dolphinear is an instrument for monitoring sound wave signals underwater. This study aims to see how the results of sound recording by Dolphinear type DE200 based on variations in distance and frequency of the sound source using the Audacity Software. In this study, the sound source will be generated through a waterproof speaker with a frequency variation of 100 Hz to 20 kHz. The distance between the sound source and the dolphinear is also varied from 1 to 5 meters. Audacity software is used to generate, record, and obtain the spectrum of the recorded audio sound signal. Based on the spectrum of the sound recorded by the DE200 dolphinear, frequency peaks close to the source frequency can be detected in recording using a 500 Hz sound source, but the main frequency peaks in the spectrum are difficult to detect in recording using sound sources above 500 Hz. In this study, it was also found that there is a limit to the recording ability of the dolphinear DE200 for frequencies above 18 kHz which is indicated by a decrease in intensity at that frequency.

Analysis of the Effect of Local Magnitude on Peak Ground Acceleration and Seismic Vulnerability Index for Geothermal Field Monitoring Using Microearthquake

Intensive exploitation of geothermal injection and production can trigger microearthquakes which it signals come from dynamic fractures. The purpose of this study is to decide the impact of local magnitude on mitigation in geothermal fields based on soil acceleration and vulnerability of seismic in geothermal fields. This study uses seismic wave recording data and the geology of the research area. It is focable on calculating local magnitude, ground acceleration and seismic susceptibility index to earthquakes based on ground acceleration and seismic susceptibility index in geothermal fields. The maximum amplitude value represent that the medium classification class (3&lt;A0&lt;6) is associated with a moderate degree of deformation. Natural frequency value are found with a moderate classification (4&lt;f0&lt;10) around the area of injection wells and production wells, indicating that the research area has a moderate level of soil hardness structure. The peak ground acceleration in the study area is classified as moderate (0.25&lt;PGA&lt;0.7) which means that the area has a moderate level of risk. Vulnerability of seismic in the study area is included in the low classification (Kg&lt;10). The local magnitude impact on soil acceleration and vulnerability of seismic in this study has a moderate risk and can be categorised as safe. In the future, this research serves as a basis for proper decision-making in geothermal energy operations, monitoring, and infrastructure development

Large aperture and defect-free liquid crystal planar optics enabled by high-throughput pulsed polarization patterning.

The liquid crystal (LC) geometrical phase optics, which is realized by the high-resolution control of the optical axis orientation in transparent micrometer-thin polymer films, is emerging as a next generation of planar optics. It features pronounced optical properties and stimuli-responsive behaviors, which could introduce appealing and new possibilities for photonic purposes. The development of fabrication techniques producing elements with large aperture sizes and arbitrarily varying molecular orientation is of significance in terms of practical utility. Here, we propose the pulsed polarization patterning technique to create large-aperture and defect-free LC geometrical phase elements. We investigated the capability of the azo photo-alignment material responding to nanosecond laser pulses and the corresponding anchoring behaviors to LCs. The threshold was reduced to one fourth of that under the continuous wave recording. The patterning resolution was found to be enhanced to around 0.71 µm, due to the ultra-fast interaction nature of the photo-alignment material with the polarized light field. We proposed the flying exposure mode to deliver high frequency modulated polarized laser pulses (8 kHz), with the precision stage moving in a uniform velocity for light-field stitching and the servo auto-focusing in the sample normal, enabling the stable and reliable polarization patterning for large aperture sizes. We further report on representative fabrication of LC polarization gratings with an aperture of 4 inch and 99.2% average diffraction efficiency.