Filter Analysis Method Research Articles

Inferring neutral winds in the ionospheric transition region from atmospheric-gravity-wave traveling-ionospheric-disturbance (AGW-TID) observations with the EISCAT VHF radar and the Nordic Meteor Radar Cluster

Abstract. Atmospheric gravity waves and traveling ionospheric disturbances can be observed in the neutral atmosphere and the ionosphere at a wide range of spatial and temporal scales. Especially at medium scales, these oscillations are often not resolved in general circulation models and are parameterized. We show that ionospheric disturbances forced by upward-propagating atmospheric gravity waves can be simultaneously observed with the EISCAT very high frequency incoherent scatter radar and the Nordic Meteor Radar Cluster. From combined multi-static measurements, both vertical and horizontal wave parameters can be determined by applying a specially developed Fourier filter analysis method. This method is demonstrated using the example of a strongly pronounced wave mode that occurred during the EISCAT experiment on 7 July 2020. Leveraging the developed technique, we show that the wave characteristics of traveling ionospheric disturbances are notably impacted by the fall transition of the mesosphere and lower thermosphere. We also demonstrate the application of using the determined wave parameters to infer the thermospheric neutral wind velocities. Applying the dissipative anelastic gravity wave dispersion relation, we obtain vertical wind profiles in the lower thermosphere.

Shallow crustal model of the DehDasht in Zagros, Iran, using Rayleigh wave tomography

Surface wave tomography is considered an efficient method to reveal the physical properties of subsurface geological structures, particularly beneath geologically complex areas where conventional active seismic methods are problematic. The salt-rich DehDasht structural basin, in the SW of Iran, is an example of this area, which is characterized by high seismicity. Despite the complex geology and the great thickness of evaporitic deposits in this region, surface wave tomography can retrieve high-resolution images by applying a dense network of stations. Therefore, >11,000 micro-earthquakes (M ≤ 3.0) recorded by 116 broadband stations in 9 months were processed to detect geological structures and a crustal model beneath the DehDasht region. After selecting strict data selection criteria, the observed dispersion curves of Rayleigh waves were then measured using the multiple filter analysis method, and the 2D tomography was done for periods of 0.3 to 5.0 s. A non-linear iterative damped least-squares inversion procedure was then applied to each local dispersion curve to obtain the 1D VS model of the uppermost 5 km, and the results were inserted into the original cells to construct a quasi-3D VS model. Although our resulted VS model has high correlations with known geological units and tectonic features of the study area, we validated it by inverting the observed gravity data independently and consequently recovering the location of the anomalies at the basin and/or around faults, anticlines, and synclines. Generally, the observed low-and high-velocity anomalies are associated with the sedimentary materials.

Shear wave velocity structure beneath Bandung basin, West Java, Indonesia from ambient noise tomography

Summary We investigated the seismic shear wave velocity structure of the upper crust beneath the Bandung area in West Java, Indonesia, using ambient seismic noise tomography. We installed 60 seismographs to record ambient seismic noise continuously in the city of Bandung and its surrounding area for 8 months. After inter-station cross-correlation of recordings of ambient seismic noise, we obtained empirical Green's functions for Rayleigh waves. Group velocity dispersion curves for Rayleigh waves between periods of 1 s and 8 s were measured on each inter-station path by applying the multiple filter analysis method with phase-matched processing. The spatial variation of group velocities shows a good correlation with the geological structure of the Bandung Basin. The Rayleigh wave dispersion maps were inverted to obtain the 1D shear wave velocity profiles beneath each station, which were interpolated to infer a pseudo-3D structure under the study region. The results show that the Bandung Basin has a thick layer of sediment. Along the northern, eastern and southern mountains surrounding the Bandung Basin there is high-velocity structure, except to the west of the Tangkuban Parahu volcano, where a massive low-velocity structure extending throughout the upper crust might indicate the presence of fluids or partial melts.

Effects of meteorology and emission reduction measures on air pollution in Beijing during heating seasons

Beijing implemented five-year clean air plan during 2013–2017, and realized the continuous improvement of air quality in the whole city year by year. In this study, the MK (Mann-Kendall) test and KZ (Kolmogorov-Zurbenko) filtering analysis method were applied to evaluate the variations of PM2.5 concentration at different sites in Beijing before and after the filtering meteorological conditions. The results showed that the averaged PM2.5 concentrations in five sites decreased by 29.82% after filtering weather conditions, which was significantly lower than the average decrease rate (33.61%) of the original data. The emissions by human activities contributed about 69–94% to the decreased PM2.5 concentrations during 2013–2017 at different sites in Beijing while the meteorological conditions contributed not more than 31% indicating the leading role of the emission reduction measures in the air quality improvement in Beijing. Contrary to the monthly averaged trends, the original PM2.5 concentrations in heating seasons during 2013–2016 did not decrease obviously and not passed the significant test (α = 0.1) due to the unfavor weather conditions which always aggravated degree and duration of air pollution. In order to further improve air quality, emission reduction measures such as reducing coal combustion, reducing oil consumption, controlling vehicles, emissions reduction, and cleaning dust should be continuously promoted.

“ABED TANGI” As a Solution for Time Inaccuracy in Returning Medical Record at X Hospital

This study aims to determine the root of problem and alternative solutions of inaccuracy return medical record inpatient files. The research was conducted through qualitative descriptive approach in RSUD Blambangan from September until October 2017. Data was collected by document review, field observation and unstructured interview with Head of Services, Head of Nursing Services, 1 doctor, 2 head of ward, Head of Medical Record Installation, Head of Nutrition Installation and Head of Pharmacy Installation. Root of problem was analyzed with fishbone diagram, focus group discussion (FGD) method and urgency, seriousness, growth (USG) method. Priority determination solution is carried out using filter analysis method with CARL (Capability Accessibility Readiness Leverage). The results show that factor inaccuracy return inpatient medical records file because are incomplete of medical record file, absence of standard opera t i ng procedure and unavailability of monitoring and evaluation, and the increasing number of medical record form according to hospital quality standard. The root problem is not optimally main task and function of professional care giver when filling medical record. Alternative proposed solutions is socialization to professional care giver, revised standard of operational procedure, and monitoring evaluation of the completeness and timeliness of medical record file returns with innovation ABED TANGI .

Analysis of group-velocity dispersion of high-frequency Rayleigh waves for near-surface applications

The Multichannel Analysis of Surface Waves (MASW) method is an efficient tool to obtain the vertical shear (S)-wave velocity profile using the dispersive characteristic of Rayleigh waves . Most MASW researchers mainly apply Rayleigh-wave phase-velocity dispersion for S-wave velocity estimation with a few exceptions applying Rayleigh-wave group-velocity dispersion. Herein, we first compare sensitivities of fundamental surface-wave phase velocities with group velocities with three four-layer models including a low-velocity layer or a high-velocity layer. Then synthetic data are simulated by a finite difference method . Images of group-velocity dispersive energy of the synthetic data are generated using the Multiple Filter Analysis (MFA) method. Finally we invert a high-frequency surface-wave group-velocity dispersion curve of a real-world example. Results demonstrate that (1) the sensitivities of group velocities are higher than those of phase velocities and usable frequency ranges are wider than that of phase velocities, which is very helpful in improving inversion stability because for a stable inversion system, small changes in phase velocities do not result in a large fluctuation in inverted S-wave velocities; (2) group-velocity dispersive energy can be measured using single-trace data if Rayleigh-wave fundamental-mode energy is dominant, which suggests that the number of shots required in data acquisition can be dramatically reduced and the horizontal resolution can be greatly improved using analysis of group-velocity dispersion; and (3) the suspension logging results of the real-world example demonstrate that inversion of group velocities generated by the MFA method can successfully estimate near-surface S-wave velocities. ► Sensitivities of fundamental surface-wave phase velocities and group velocities with three four-layer models including a low-velocity layer or a high-velocity layer were compared. ► Images of group-velocity dispersive energy of the synthetic data are generated using the Multiple Filter Analysis method. ► A high-frequency surface-wave group-velocity dispersion curve of a real-world example was inverted.

Three-dimensional S-wave velocity structure in eastern Tibet from ambient noise Rayleigh and love wave tomography

We apply ambient noise tomography to continuous three-component broadband seismic data between January 1, 2008 and December 31, 2008 from the regional networks of 76 stations deployed by China Earthquake Administration. Ambient noise cross-correlations were performed to produce the Green’s functions of each station-pair. Within the period from 6 to 50 s, Rayleigh and Love wave dispersion curves were measured using the multiple filter analysis method. Then three-dimensional (3-D) S-wave velocity structures from the surface down to 70 km are inverted from both Rayleigh and Love wave dispersion results. The obtained S-wave velocity maps show strong lateral variations and correlate well with the distinct geological and tectonic features in the study area. The Sichuan basin displays low velocity in shallow depth due to thick sedimentary deposits but high velocity in the mid-lower crust; the eastern Tibetan plateau is clearly featured with a low-velocity zone in its mid-to-lower crust which is consistent with the crustal flow model proposed to explain the mechanism of uplift and pattern of deformation for the Tibetan plateau. Meanwhile, our results also exhibit that the crustal thickness decreased from the eastern Tibetan plateau to the Sichuan basin.

A survey of mouth level exposure to cigarette smoke in the United States

Smoke yields determined by a machine-based smoking method cannot adequately predict exposures experienced by human smokers. In this work, a filter analysis technique which addresses this fundamental limitation was used to measure mouth level exposures (MLE) to tar and nicotine in 1330 smokers of 26 brand-styles of US cigarettes covering a wide range of machine-generated yields.Despite the high degree of variability observed among individual smokers, MLEs were significantly correlated with machine-derived tar and nicotine yields (r=0.423 for nicotine MLE/cigarette; r=0.493 for tar MLE/cigarette; p<0.001 for both). Mean tar and nicotine MLE was higher for males than for females. Mean MLE across races was generally similar. Menthol cigarettes tended toward lower MLE than non-menthol cigarettes and King-Size cigarettes (∼83mm) tended toward lower MLE than 100’s cigarettes (∼100mm), though those trends were not statistically significant.There were good agreements between MLEs measured in a group of 159 subjects smoking their usual cigarette brand-style on two separate occasions and between two independent groups of subjects smoking the same brand-styles. The results indicated that the filter analysis method used had sufficient precision to show similarity among groups.

Estimation of nicotine and tar yields from human-smoked cigarettes before and after the implementation of the cigarette ignition propensity regulations in Canada

In 2005, Human-Smoked (HS) tar and nicotine yields from commercial Canadian cigarettes were determined using a part filter analysis method to obtain estimates representative of human smoking behavior. In 2006, new cigarette designs were introduced to ensure compliance with the Canadian Low Ignition Propensity (LIP) regulations. It was not known how the changes in product design would affect HS yields. To assess the impact of the cigarette design modifications on HS yields, a further group of Canadian smokers was recruited for smoking the modified version of 10 products previously assessed. No differences in estimated HS tar yields were found between products following product modification. The HS nicotine yield was different for one product. In general, HS yields were higher than ISO machine yields while Canadian intense machine yields were more representative of the maximum HS yields. The same product ranking order was obtained for HS yields and the two machine yields but differences between the mean HS yields and ISO yields were smaller as the product ISO yields increased. Higher HS yields were measured when products were smoked by male smokers. The methodology used in this study showed the wide range of HS yields obtained by smokers as well as a good degree of stability in average HS yields just before and after the introduction of LIP regulations.

Estimating tar and nicotine exposure: Human smoking versus machine generated smoke yields

Determine human smoked (HS) cigarette yields of tar and nicotine for smokers using their own brand in their everyday environment. A robust, filter analysis method was used to estimate the tar and nicotine yields for 784 subjects. Seventeen brands were chosen to represent a wide range of styles: 85 and 100 mm lengths; menthol and non-menthol; 17, 23, and 25 mm circumference; with tar yields [Federal Trade Commission (FTC) method] ranging from 1 to 18 mg. Tar bands chosen corresponded to yields of 1-3 mg, 4-6 mg, 7-12 mg, and 13+ mg. A significant difference (p<0.0001) in HS yields of tar and nicotine between tar bands was found. Machine-smoked yields were reasonable predictors of the HS yields for groups of subjects, but the relationship was neither exact nor linear. Neither the FTC, the Massachusetts (MA) nor the Canadian Intensive (CI) machine-smoking methods accurately reflect the HS yields across all brands. The FTC method was closest for the 7-12 mg and 13+ mg products and the MA method was closest for the 1-3mg products. The HS yields for the 4-6 mg products were approximately midway between the FTC and the MA yields. HS nicotine yields corresponded well with published urinary and plasma nicotine biomarker studies.

A comparison of nicotine dose estimates in smokers between filter analysis, salivary cotinine, and urinary excretion of nicotine metabolites

RationaleNicotine uptake during smoking was estimated by either analyzing the metabolites of nicotine in various body fluids or by analyzing filters from smoked cigarettes. However, no comparison of the filter analysis method with body fluid analysis methods has been published.ObjectivesCorrelate nicotine uptake estimates between filter analysis, salivary cotinine, and urinary excretion of selected nicotine metabolites to determine the suitability of these methods in estimating nicotine absorption in smokers of filtered cigarettes.Materials and methodsA 5-day clinical study was conducted with 74 smokers who smoked 1–19 mg Federal Trade Commission tar cigarettes, using their own brands ad libitum. Filters were analyzed to estimate the daily mouth exposure of nicotine. Twenty-four-hour urine samples were collected and analyzed for nicotine, cotinine, and 3′-hydroxycotinine plus their glucuronide conjugates. Saliva samples were collected daily for cotinine analysis.ResultsEach method correlated significantly (p < 0.01) with the other two. The best correlation was between the mouth exposure of nicotine, as estimated by filter analysis, and urinary nicotine plus metabolites. Multiple regression analysis implies that saliva cotinine and urinary output are dependent on nicotine mouth exposure for multiple days. Creatinine normalization of the urinary metabolites degrades the correlation with mouth exposure.ConclusionsThe filter analysis method was shown to correlate with more traditional methods of estimating nicotine uptake. However, because filter analysis is less complicated and intrusive, subjects can collect samples easily and unsupervised. This should enable improvements in study compliance and future study designs.

Effect of the vocal tract yielding sidewall on inverse filter analysis of the glottal waveform

Summary The inverse filter is a serial cascade of filter elements with a transfer function that cancels the effect of the poles of the vocal tract transfer function on the acoustic waveform to reveal the underlying glottal volume velocity waveform. Inaccuracies in the glottal wave reconstruction derived from an all-zero inverse filter can be attributed to deviations of the vocal tract transfer function from an all-pole model. Presented is an analysis of the error stemming from the effect of the yielding vocal tract sidewalls on the vocal tract transfer function. Predictions about the resulting artifacts in the estimated glottal volume velocity are derived from an acoustic model. These predictions are confirmed by applying a linear predictive coding (LPC) inverse filter analysis method to vowels synthesized using a transmission line model of the vocal tract containing yielding sidewall parameters as well as natural productions of nonnasalized vowels.

A fast new method for frequency-filter analysis of surface waves: Application in the west pacific

abstract A very simple modification to the Dziewonski multiple filter analysis method for surface-wave data yields a 90 per cent reduction in computation time. The method involves a frequency shift such that the center frequency of the bandpass filter is moved to the origin. The effect is to greatly reduce the apparent bandwidth and allow a reduction of the inverse transform size down to only 256 points. The new method was used to analyze Rayleigh waves for 32 paths to Guam in the southwest Pacific. Results support the existence of a very thick crustal region north of the Fiji Plateau. Data from Samoa exhibited the highest group velocities, peaking at 4.0 km/sec; other regions generally showed anomalously low-group velocities, reflecting the anomalous mantle structure known to exist in many parts of the region.