Sensitivity of the Vertical Response of Footbridges to the Frequency Variability of Crossing Pedestrians

Contemporary design codes and guides for vibration serviceability assessment include some simplifications in load modelling. The same statistical distribution of the inter-pedestrian variability of the step interval (frequency) is proposed for all applications. Moreover, walking loads are considered to be periodic. The intra-pedestrian variability of the step interval is neglected. A more realistic load modelling trying to overcome the limitations of the codes is intended in this paper. Instead of a single mean value of the inter-pedestrian distribution of walking speed, a range of possible variation, which account for the real variations that occur in practice depending on the footbridge location and usage, is considered. An enhanced model is proposed in this paper to reproduce statistically both the intra- and inter-pedestrian variability of the step interval as a function of the walking speed distribution. This innovative model is then applied to study the sensitivity of the vertical response of footbridges to the variability of the step interval and to evaluate the influence of the aforementioned simplifications on the predicted characteristic responses. For this purpose, low-frequency footbridges excited by single-pedestrian crossings are chosen. The response is statistically characterized through Monte Carlo numerical simulations including 720 different configurations and 10,000 load cases in each configuration. Results of the study provide an overview of the influence of the footbridge and load parameters on the responses, which can be useful in practical applications where human–structure interactions are negligible. As for the simplifications of the codes, it is found that either using a single distribution to model the inter-pedestrian variability of the spatiotemporal parameters or neglecting the intra-pedestrian variability can lead to a significant underestimation of the characteristic response of footbridges.

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An Identity-Based Blind Signature Scheme Using Lattice with Provable Security

Mathematical Problems in Engineering ◽

10.1155/2020/7528571 ◽

2020 ◽

Vol 2020 ◽

pp. 1-12

Author(s):

Quanrun Li ◽

Chingfang Hsu ◽

Debiao He ◽

Kim-Kwang Raymond Choo ◽

Peng Gong

Keyword(s):

Quantum Computer ◽

Rapid Development ◽

Random Oracle Model ◽

Random Oracle ◽

Mean Value ◽

Blind Signature ◽

Signature Scheme ◽

Practical Applications ◽

Universal Quantum ◽

Identity Based

With the rapid development of quantum computing and quantum information technology, the universal quantum computer will emerge in the near decades with a very high probability and it could break most of the current public key cryptosystems totally. Due to the ability of withstanding the universal quantum computer’s attack, the lattice-based cryptosystems have received lots of attention from both industry and academia. In this paper, we propose an identity-based blind signature scheme using lattice. We also prove that the proposed scheme is provably secure in the random oracle model. The performance analysis shows that the proposed scheme has less mean value of sampling times and smaller signature size than previous schemes. Thus, the proposed scheme is more suitable for practical applications.

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Polytetrafluoroethylene Films in Rigid Polyurethane Foams’ Dielectric Permittivity Measurements with a One-Side Access Capacitive Sensor

Polymers ◽

10.3390/polym13071173 ◽

2021 ◽

Vol 13 (7) ◽

pp. 1173

Author(s):

Ilze Beverte ◽

Ugis Cabulis ◽

Sergejs Gaidukovs

Keyword(s):

Dielectric Properties ◽

Dielectric Permittivity ◽

Low Frequency ◽

Capacitive Sensor ◽

Polyurethane Foams ◽

Active Area ◽

Ptfe Film ◽

Practical Applications ◽

Permittivity Measurements ◽

The Impact

As a non-metallic composite material, widely applied in industry, rigid polyurethane (PUR) foams require knowledge of their dielectric properties. In experimental determination of PUR foams’ dielectric properties protection of one-side capacitive sensor’s active area from adverse effects caused by the PUR foams’ test objects has to be ensured. In the given study, the impact of polytetrafluoroethylene (PTFE) films, thickness 0.20 mm and 0.04 mm, in covering or simulated coating the active area of one-side access capacitive sensor’ electrodes on the experimentally determined true dielectric permittivity spectra of rigid PUR foams is estimated. Penetration depth of the low frequency excitation field into PTFE and PUR foams is determined experimentally. Experiments are made in order to evaluate the difference between measurements on single PUR foams’ samples and on complex samples “PUR foams + PTFE film” with two calibration modes. A modification factor and a small modification criterion are defined and values of modifications are estimated in numerical calculations. Conclusions about possible practical applications of PTFE films in dielectric permittivity measurements of rigid PUR foams with one-side access capacitive sensor are made.

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Nycthemeral Rhythm of the Frequency and Biomechanical Energy of High Frequency Intraocular Pressure Fluctuations

Volume 1A: Abdominal Aortic Aneurysms; Active and Reactive Soft Matter; Atherosclerosis; BioFluid Mechanics; Education; Biotransport Phenomena; Bone, Joint and Spine Mechanics; Brain Injury; Cardiac Mechanics; Cardiovascular Devices, Fluids and Imaging; Cartilage and Disc Mechanics; Cell and Tissue Engineering; Cerebral Aneurysms; Computational Biofluid Dynamics; Device Design, Human Dynamics, and Rehabilitation; Drug Delivery and Disease Treatment; Engineered Cellular Environments ◽

10.1115/sbc2013-14776 ◽

2013 ◽

Author(s):

Vincent Libertiaux ◽

William P. Seigfreid ◽

Massimo A. Fazio ◽

Juan F. Reynaud ◽

Claude F. Burgoyne ◽

...

Keyword(s):

Intraocular Pressure ◽

High Frequency ◽

Pressure Fluctuations ◽

Low Frequency ◽

Pulse Amplitude ◽

Mean Value ◽

Multiple Time Scales ◽

Dynamic Contour Tonometry ◽

Multiple Time ◽

Ocular Pulse

The optic nerve head (ONH) is the site of insult in glaucoma, the second leading cause of blindness worldwide. Intraocular pressure (IOP) is commonly regarded as a major factor in the onset and progression of the disease1 and lowering IOP is the only clinical treatment that has been shown to retard the onset and progression of glaucoma2. However, many patients continue to progress even at an epidemiologically-determined normal level of IOP3. This suggests that in addition to the mean value of IOP, IOP fluctuations could be a factor in glaucomatous pathophysiology. The importance of low frequency fluctuations of clinically-measured mean IOP remains controversial. These studies all rely on snapshot measurements of mean IOP at each time point, and those measurements are taken at relatively infrequent intervals (hourly at the most frequent, but usually monthly or longer). Recently however, there has been some interest in ocular pulse amplitude, or the fluctuation in IOP associated with the cardiac cycle, which can be measured by Dynamic Contour Tonometry (DCT). DCT provides continuous measurement of IOP, but only for a period of tens of seconds in which a patient can tolerate corneal contact without blinking or eye movement, which ironically are two of the most common sources of large high frequency IOP fluctuations according to our telemetric data collected from monkeys4 and previous human studies. In a recent report, continuous IOP telemetry was used in three nonhuman primates to characterize IOP dynamics at multiple time scales for multiple 24-hour periods5.

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Eliminating Phase Drift for Distributed Optical Fiber Acoustic Sensing System with Empirical Mode Decomposition

Sensors ◽

10.3390/s19245392 ◽

2019 ◽

Vol 19 (24) ◽

pp. 5392 ◽

Cited By ~ 1

Author(s):

Yuejuan Lv ◽

Pengfei Wang ◽

Yu Wang ◽

Xin Liu ◽

Qing Bai ◽

...

Keyword(s):

Empirical Mode Decomposition ◽

Low Frequency ◽

Time Domain Reflectometry ◽

Coherent Detection ◽

Characteristic Time Scale ◽

Phase Drift ◽

Practical Applications ◽

Mode Decomposition ◽

Negative Effect ◽

Signal Fluctuation

Phase-drift elimination is crucial to vibration recovery in the coherent detection phase-sensitive optical time domain reflectometry system. The phase drift drives the whole phase signal fluctuation as a baseline, and its negative effect is obvious when the detection time is long. In this paper, empirical mode decomposition (EMD) is presented to extract and eliminate the phase drift adaptively. It decomposes the signal by utilizing the characteristic time scale of the data, and the baseline is eventually obtained. It is validated by theory and experiment that the phase drift deteriorates seriously when the length of the vibration region increases. In an experiment, the phase drift was eliminated under the conditions of different vibration frequencies of 1 Hz, 5 Hz, and 10 Hz. The phase drift was also eliminated with different vibration intensities. Furthermore, the linear relationship between phase and vibration intensity is demonstrated with a correlation coefficient of 99.99%. The vibrations at 0.5 Hz and 0.3 Hz were detected with signal-to-noise ratios (SNRs) of 55.58 dB and 64.44 dB. With this method, when the vibration frequency is at the level of Hz or sub-Hz, the phase drift can be eliminated. This contributes to the detection and recovery of low-frequency perturbation events in practical applications.

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Molecular coding of olfactory specificity

Canadian Journal of Zoology ◽

10.1139/z75-149 ◽

1975 ◽

Vol 53 (9) ◽

pp. 1247-1253 ◽

Cited By ~ 3

Author(s):

R. H. Wright ◽

R. E. Burgess

Keyword(s):

Organic Compounds ◽

Molecular Basis ◽

Insect Pests ◽

Low Frequency ◽

Olfactory Stimulation ◽

Primary Process ◽

Vibrational Modes ◽

Physiological Mechanisms ◽

Practical Applications

An analysis of the low-frequency vibrational modes of organic compounds in 19 odor categories indicates that the primary process of olfactory stimulation is common to both vertebrates and insects. Understanding the molecular basis of olfactory specificity may provide a clue to the physiological mechanisms and has immediate practical applications in the control of insect pests.

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Acute Fingolimod Effects on Baroreflex and Cardiovascular Autonomic Control in Multiple Sclerosis

Journal of Central Nervous System Disease ◽

10.1177/1179573519849945 ◽

2019 ◽

Vol 11 ◽

pp. 117957351984994 ◽

Cited By ~ 1

Author(s):

Vittorio Racca ◽

Marco Rovaris ◽

Rosella Cavarretta ◽

Emanuele Vaini ◽

Anastasia Toccafondi ◽

...

Keyword(s):

Multiple Sclerosis ◽

Baroreflex Sensitivity ◽

Low Frequency ◽

Acute Effect ◽

Mean Value ◽

Autonomic Control ◽

Oral Drug ◽

Pulse Interval ◽

Dose Administration ◽

Parasympathetic System

Background: Fingolimod, an oral drug used in multiple sclerosis (MS) treatment, exerts its action through S1P-receptor engagement. These receptors are also expressed in heart and endothelial cells. The engagement of receptors on the atrial heart myocytes may cause a slowing effect on heart rate (HR). We aimed to explore the acute effect of fingolimod on the cardiac autonomic control, a side-effect of the drug that still needs to be clarified. Methods: In 10 MS patients, we investigated the influence of the first administration of fingolimod (0.5 mg) on sympathetic and parasympathetic indexes via the analysis of the HR variability, and on the baroreflex sensitivity via sequence and alpha coefficient techniques. Results: Fingolimod produced an average HR maximal drop of 12.7 (7.8) beats/min and the minimal HR occurred after 2.73 (0.38) hours from the dose administration. The pulse interval (PI) mean value and the pNN50 and RMSSD indexes of parasympathetic drive to the heart significantly increased. Interestingly, in 6 out of 10 patients also the power in the low-frequency band (LF) increased. The baroreflex sensitivity was not modified by the first dose of the drug. Conclusions: Our findings indicate that although the first dose of fingolimod invariably activates the parasympathetic system, in several subjects, it may induce also a surge in the sympathetic cardiac drive. This suggests that not only the vagal, as usually assumed, but also the sympathetic autonomic branch should be considered in the risk profile assessment of MS patients starting treatment with fingolimod.

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Rapid Laser Reactive Sintering Synthesis of Colossal Dielectric CCTO Ceramics

Applied Sciences ◽

10.3390/app10103510 ◽

2020 ◽

Vol 10 (10) ◽

pp. 3510

Author(s):

Jiayang He ◽

Yanwei Huang ◽

Guang Feng ◽

Si Shen ◽

Ming Yan ◽

...

Keyword(s):

Impedance Spectroscopy ◽

Dielectric Permittivity ◽

Laser Power ◽

Low Frequency ◽

Reactive Sintering ◽

Practical Applications ◽

Dense Microstructure ◽

Calcium Copper Titanate ◽

Average Grain Size ◽

In Series

Calcium copper titanate (CCTO) ceramics were successfully synthesized using a rapid laser reactive sintering method without conventional long heat treatment times. The microstructure, dielectric properties, and impedance spectroscopy results for CCTO sintered at laser power rates of 25–85 W were investigated in detail. The X-ray diffractometry results showed that prepared CCTO is polycrystalline in a cubic structure with high purity. Scanning electron microscopy showed that CCTO sintered at 85 W has a dense microstructure with an average grain size of 30 nm. The dielectric permittivity of CCTO ceramics increased with increasing laser power over the entire frequency range and achieved a value of almost 105 in the low-frequency region. The dielectric permittivity maintained almost constant values from 102 Hz to 107 Hz, with lower dielectric loss (~0.1) from 103 Hz to 106 Hz, demonstrating good frequency stability. The impedance spectroscopy study showed that grain and grain boundary resistance decreased with rising laser power based on two parallel Resistor-Capacitance (RC) equivalent circuits in series. The activation energies for the grain boundaries were calculated from the impedance using the slope of ln σ versus 1/T and were found to be in the range of 0.53–0.63 eV. CCTO synthesized by rapid laser reactive sintering is competitive for practical applications.

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Antibody Reactivity to α-Enolase in Mothers of Children with Congenital Heart Block

The Journal of Rheumatology ◽

10.3899/jrheum.080860 ◽

2009 ◽

Vol 36 (3) ◽

pp. 565-569 ◽

Cited By ~ 11

Author(s):

CAROLINA LLANOS ◽

EDWARD K.L. CHAN ◽

SONGQING LI ◽

GRANT X. ABADAL ◽

PETER IZMIRLY ◽

...

Keyword(s):

Lupus Erythematosus ◽

Heart Block ◽

Congenital Heart ◽

Low Frequency ◽

Mean Value ◽

Cross Reactivity ◽

Congenital Heart Block ◽

Neonatal Rat ◽

Neonatal Rat Heart ◽

The Mean

Objective.To evaluate the frequency of anti-α-enolase antibodies in the sera of mothers whose children have congenital heart block (CHB), given provocative results in which α-enolase, a membrane protein, was recognized by monoclonal antibodies reactive with the peptide p200 of 52 kDa Ro/SSA in a neonatal rat heart library.Methods.An ELISA using a recombinant α-enolase protein was developed. Sera from 100 anti-Ro52+ CHB mothers in the Research Registry for Neonatal Lupus, 50 patients with systemic lupus erythematosus (SLE; 7 anti-Ro52+), and 48 healthy controls were tested for anti-α-enolase reactivity.Results.There were no significant differences in the median values obtained from CHB mothers, patients with SLE, or controls at each of the dilutions tested. Only 7 (7%) at 1:100 dilution and 2 (2%) at 1:1000 dilution of 100 CHB sera were 3 standard deviations above the mean value obtained for controls. Preincubation with recombinant Ro52 did not inhibit anti-α-enolase reactivity.Conclusion.The low frequency of anti-α-enolase antibodies in the sera of CHB mothers and the absence of apparent cross-reactivity with Ro52 suggest that antibodies to Ro52 are not likely to mediate CHB via binding to α-enolase.

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Fully Automated Identification of Dysplastic Neutrophil in Peripheral Blood Using the Positional Parameters Provided by the Coulter LH750 Analyzer.

Blood ◽

10.1182/blood.v106.11.4904.4904 ◽

2005 ◽

Vol 106 (11) ◽

pp. 4904-4904

Author(s):

Gina Zini ◽

Mariagrazia Garzia ◽

Antonella Di Mario ◽

Bianca Maria Ricerca ◽

Paola Piccioni ◽

...

Keyword(s):

Peripheral Blood ◽

Cell Structure ◽

Low Frequency ◽

High Volume ◽

Mean Value ◽

Moderate Increase ◽

Automated Identification ◽

Data Set ◽

Internal Cell ◽

The Mean

Abstract The hematology analyzer Coulter LH750 provides WBC differential counts using the VCS technology, which combines three simultaneous measurements (Volume, Conductivity, Scatter) to classify circulating blood cells. Cell volume and internal cell structure (opacity) are detected, respectively, by applying a low frequency direct current (DC) and a high frequency alternative (RF) current. The light scattered at different angles between 10° and 70°, on the other hand, is proportional to cell size, granularity, surface topography and reflectance. The system also provides for the main four WBC subtypes (neutrophils, lymphocytes, monocytes, eosinophils) a set of data called ‘positional parameters’ (PP). They express the mean value and the standard deviation (SD) of the three VCS measurements. We focused our study to the analysis of PP of the neutrophil population in normal and in pathological samples in order to: i) evaluate any correspondence with morphology and ii) determine the predictivity of changes in these parameters for the presence of morphological abnormalities. We analysed 100 samples from healthy subjects, 59 males and 41 females, age ranged from 2 years to 79 years, (25 children, 75 adults) to define our neutrophil reference PP ranges. We found a mean volume of 151,7 (SD ± 22,5), a mean opacity of 143,9 (SD ± 7,4) and a mean scatter of 142,19 (SD ± 13,1), without consistent differences due to age or sex. Our results do agree with those found in the literature. In normal samples we could not observe, as expected, any morphological abnormality at the microscope. Thereafter we also analyzed 16 samples from patients with bacterial pneumonitis. Their PP showed a moderate increase in the mean volume (168,9 with SD ± 24,1), a normal value of opacity and a slight decrease of the mean scatter (138,2 with SD ±14.4). Microscope analysis showed granulocytes with normal morphology, sometimes with toxic granules and the presence of band forms and metamyelocytes above 7%. The analysis of the PP of 11 patients with chronic myeloid leukemia at diagnosis showed an increase in the mean volume (160,1) with a consistently highly SD (± 33,4); opacity (142,8 with SD ± 11,7) and scatter (143,9 with SD ± 12,3) were normal. At the microscope the morphology of neutrophils was normal, with the presence of circulating immature granulocytes (range 22–28%). Finally we analyzed samples from N 28 patients with myelodysplastic syndromes (14 RA, 5 RC, 9 RAEB Type 1). Circulating granulocytes showed a great increase in the mean volume with a wide dispersion (178,2 with SD ± 35,6 ), a decreased mean opacity (132 with SD ± 8,3) and very low mean scatter value (119,9 with SD ± 12,4). At microscope neutrophils showed characteristic dysplastic features, such as abnormal nuclear segmentation, chromatin clumping and hypogranularity. Our study demonstrates the Coulter LH750 PP are highly predictive of the presence of dysplastic neutrophils in the peripheral blood. We have found a peculiar data set (high volume with increased SD, low opacity and scatter with small SD) which is easily distinguishable from normal as well as from other types of neutrophil abnormalities, such as myloproliferative and bacterial diseases. These parameters are automatically available during the routine load of hematology laboratories and can be usefully utilized to screen and to early identify patients with mylodysplasia.

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