Pulse Transmission Research Articles

Alternating minimisation approach for direct position determination in passive localisation

AbstractThis article deals with the source localisation problem when the receiver is moving over time, and the sources are sparse across the area. In addition, only one of the sources is active at each time instant, means that the sources are pulse transmitters. The problem was first formulated such as a dictionary learning problem for sparse representation. Then, an alternating minimisation approach to estimate the position of the sources and their signals iteratively is proposed. Simulation results in different scenarios demonstrate the effectiveness of the proposed method relative to state‐of‐the‐art methods.

How to measure arterial stiffness independently of blood pressure: the QKD method.

Arterial stiffness, an important predictor of cardiovascular event, has two components: one linked to the nonlinear elastic behaviour of the arterial wall and dependent of the blood pressure (BP) at the time of measurement, and the other linked to the structural modifications of the arterial wall as the consequences of the long-term effects of all cardiovascular risk factors, including BP. This second component is certainly the most important one and can be assessed with 24-h ambulatory monitoring of cardio-arm pulse transmission time (QKD method). The working hypothesis of this study is that QKD100-60, the value of the QKD for a 100 mmHg SBP and 60 bpm heart rate is independent of 24-h SBP in both normotensive volunteers and treated hypertensive patients, in whom the long-term influence of BP is limited, whereas QKD100-60 is not independent of 24-h SBP in untreated hypertensive patients in whom high BP was able to damage the arterial wall on the long term. So we studied the relationships of QKD100-60 with 24-h BP and heart rate together with age, sex, height in multivariate regression analysis in three groups of patients; normal, untreated and treated hypertensive patients. QKD was measured with Novacor devices. In the normal population (n = 323, aged 29 ± 10 years) and in the treated hypertensive population (n = 425, aged 58 ± 13 years) the QKD100-60 was indeed not significantly related to 24-h SBP. In the untreated hypertensive population (n = 614, aged 51 ± 13 years) the QKD100-60 was weakly but significantly related to 24-h SBP (r = 0.249, P < 0.0001). Ambulatory monitoring of QKD provides indices of arterial stiffness independent of BP level at the time of measurement and most interestingly of 24-h BP with the potential to refine risk in patients with low traditional risk scores.

MODELİNG OF TRAFFİC LİGHT CONTROL SYSTEMS

Traffic light control systems are commonly utilized to monitor and manage the flow of autos across multiple road intersections. Since traffic jams are ubiquitous in daily life, A crucial aim is to optimize the functioning of traffic signals for optimal traffic flow. Traffic light control systems aim to make sure automobiles flow smoothly along transit routes. However, considering the numerous parameters involved, synchronizing several traffic signal systems at neighboring junctions is a difficult challenge. Conventional systems are incapable of dealing with varied flows nearing intersections. Furthermore, the present traffic system does not account for reciprocal interference between nearby traffic signal systems, the asymmetry of automobile flow with time, accidents, the passage of emergency vehicles, and pedestrian crossings. This causes traffic congestion and jams. The goal is to provide an artificial intelligence-based method that enables adaptive management of traffic lights at an intersection to reduce traffic congestion in transportation. A simulation is also created to help visualize the problem and its solution. In this venture, an algorithm that enables adaptive control of congested crossings is presented to reduce traffic congestion in transportation networks. The algorithm modifies the optimal light timings to employ in the following cycle based on the number of cars in the junction and the rise in this number. To improve reliability, employing a doppler radar sensor to collect data from traffic is suggested. The transmitter pulses waves with the assistance of a doppler radar sensor, and the receiver listens for waves flowing back to the antenna as they strike objects in the atmosphere between each pulse. The distance between the antenna and the item (in this application, vehicles) may be measured simply by calculating the time it took for the wave to return to the antenna. The Doppler shift is used to illustrate the speed differential in traffic. The change in frequency or wavelength of a wave perceived by an observer moving relative to the wave's source is known as the Doppler shift. This is a common occurrence with sound and light waves. When the source of a wave approaches an observer, the frequency of the wave increases, resulting in a "blue shift." The frequency of the wave drops as the source moves away from the observer, resulting in a "redshift." As a result, the flexibility of each junction to select its signal lengths saves waiting times and guarantees that the intersection functions at peak performance. Keywords: Traffic control systems, intelligent traffic lights, modeling of traffic lights, traffic jam problems, reinforcement learning, doppler sensors.

Nonlocality-mediated spatiotemporal optical vortex generation in nanorod-based epsilon-near-zero metamaterials.

Optical vortices have myriad applications in photonics. Very recently, promising concepts of spatiotemporal optical vortex (STOV) pulses based on the phase helicity in the space-time coordinates have attracted much attention owing to their donut shape. We elaborate on the molding of STOV under the transmission of femtosecond pulses through a thin epsilon-near-zero (ENZ) metamaterial slab based on a silver nanorod array in a dielectric host. At the heart of the proposed approach is the interference of the so-called main and additional optical waves enabled by strong optical nonlocality of these ENZ metamaterials, which leads to the appearance of phase singularities in transmission spectra. The cascaded metamaterial structure is proposed for high-order STOV generation.

Coherent control of the incident light propagation in a defect one-dimensional photonic crystal

In this paper, we have discussed the transmission and reflection properties of the infrared laser pulse propagated through one-dimensional photonic crystal (1DPC) with single layer of graphene nanotrusses. The single layer graphene system interacts with a probe laser field and two coupling lights. We analytically solve the optical susceptibility of the single layer graphene system for adapting the dielectric function of the 1DPC. After that we discuss the transmission and reflection properties of the incident laser pulse on 1DPC by controlling the intensity for the coupling lights and relative phase between applied lights. We have also found that the absorption and population spectrums of the medium can be controlled by the relative phase between applied lights. Our results show that the gain without population inversion can be obtained for the simultaneous slow light propagation in the transmission and reflection pulses. Our results may have potential application in the future of the all-optical devices in quantum technologies.

Foundation of multilevel apploach to fracture modeling for materials with submicrostructure applicable for Arctic and Subarctic environment

A short review of research on multiscale modeling of the fracture processes of heterogeneous materials with submicrostructures applicable to Arctic and Subarctic environments is presented. The results of solving a number of model problems, both in terms of macroscopic strength and main crack growth, and describing the accumulation of microscopic defects and hierarchical fracture processes by the mechanisms of formation, growth, and fusion of secondary and microcracks, and microscopic pores are provided. Thus, for the fracture process of samples of porous concrete modified with oil palm fruit fibers to improve its consumer qualities, a simulation of crack growth was conducted, which showed a decrease in the crack resistance of the material with increasing fiber content. A three-point bend test was used to evaluate the bending strength and modulus of elasticity, and the compressive strength and modulus of elasticity were determined. An increase in the fiber content led to a decrease in the compressive strength and modulus of elasticity. The fracture surface analysis revealed the mechanism of crack propagation through the coalescence of micropores. The basis of the modeling was an experimentally substantiated criterion for concentrated fractures during crack formation based on percolation theory. Macroscopic finite-element and stochastic modeling of fractures during the bending of a beam made of wood have also been carried out. For wooden structures, the peculiarity is the anisotropic behavior of the material in the loading direction. The structure of the Bilinga tree timber at the mesoscopic and microscale levels was considered, and a hierarchy of the spatial and temporal scales of the fracture process was constructed. The crack growth rates at different scales were determined and compared with macroscopic FE simulations. Another task was to determine the dependence of the crack growth rate in the soil, such as regolith, under the influence of an ultrasonic impactor. Stochastic modeling of the crack growth in the array of micropores revealed the crack growth rate dependence on the ultrasonic transmitter beater parameters and pulse amplitude.

Flexible Sensors Array Based on Frosted Microstructured Ecoflex Film and TPU Nanofibers for Epidermal Pulse Wave Monitoring

Recent advances in flexible pressure sensors have fueled increasing attention as promising technologies with which to realize human epidermal pulse wave monitoring for the early diagnosis and prevention of cardiovascular diseases. However, strict requirements of a single sensor on the arterial position make it difficult to meet the practical application scenarios. Herein, based on three single-electrode sensors with small area, a 3 × 1 flexible pressure sensor array was developed to enable measurement of epidermal pulse waves at different local positions of radial artery. The designed single sensor holds an area of 6 × 6 mm2, which mainly consists of frosted microstructured Ecoflex film and thermoplastic polyurethane (TPU) nanofibers. The Ecoflex film was formed by spinning Ecoflex solution onto a sandpaper surface. Micropatterned TPU nanofibers were prepared on a fluorinated ethylene propylene (FEP) film surface using the electrospinning method. The combination of frosted microstructure and nanofibers provides an increase in the contact separation of the tribopair, which is of great benefit for improving sensor performance. Due to this structure design, the single small-area sensor was characterized by pressure sensitivity of 0.14 V/kPa, a response time of 22 ms, a wide frequency band ranging from 1 to 23 Hz, and stability up to 7000 cycles. Given this output performance, the fabricated sensor can detect subtle physiological signals (e.g., respiration, ballistocardiogram, and heartbeat) and body movement. More importantly, the sensor can be utilized in capturing human epidermal pulse waves with rich details, and the consistency of each cycle in the same measurement is as high as 0.9987. The 3 × 1 flexible sensor array is employed to acquire pulse waves at different local positions of the radial artery. In addition, the time domain parameters including pulse wave transmission time (PTT) and pulse wave velocity (PWV) can be obtained successfully, which holds promising potential in pulse-based cardiovascular system status monitoring.

Ultrasound pulse generation through continuous-wave laser excited thermo-cavitation for all-optical ultrasound imaging

The optical generation of pulsed ultrasound is attractive to nondestructive testing and biological imaging, especially for those involving narrow operation space or strong electro-magnetic interference. However, conventional techniques based on the photoacoustic effect inevitably required an expensive high-energy short pulsed laser and dedicated preparation of the optically absorptive composite film. Here, a fiber-optic ultrasound pulse transmitter based on continuous-wave (CW) laser triggered thermo-cavitation was demonstrated. The fiber-delivered CW laser light heated the highly-absorptive copper nitrate solution and generated explosive bubbles , which emitted strong ultrasound waves. Omnidirectional ultrasound pulses with an amplitude up to 0.3 MPa and a repetition rate of 5 kHz in the frequency range of 5–12 MHz were obtained by using a 50 mW optical heating power at a wavelength of 980 nm. The fiber-tip ultrasound transmitter was integrated with a polymer-cavity-based fiber ultrasound detector to construct an all-fiber ultrasound endoscopic imaging probe. Without the need for a wavelength-tunable laser, the ultrasound detector was interrogated by CW laser light with a fixed wavelength, coupled with feedback-controlled heating of the cavity to stabilize its spectral fringe. The CW laser-driven fiber ultrasound transmitter, in combination with the photothermally stabilized fiber ultrasound detector, opens new routes for a number of ultrasound-related industrial and biomedical applications.

A wideband monopolar patch antenna with a high system fidelity factor for IR‐UWB application

AbstractA compact, broadband microstrip patch antenna with stable monopole‐like radiation patterns is proposed for impulse‐radio ultrawideband (IR‐UWB) positioning systems. Such the antenna consists of a circular patch with eight conductive vias placed concentrically, resulting in the and modes. Moreover, a tapered feeding probe at its center is presented to enhance the matching and excite an antiresonance mode. The compact size of is obtained by using a square ground. The measured results show that the antenna has an impedance bandwidth of 44.1% from 6 to 9.4 GHz and stable monopole‐like radiation patterns in the frequency domain. Finally, a system fidelity factor larger than 96% and a relatively stable group delay are simulated and measured in the time domain. Therefore, this antenna can be potentially useful for UWB pulse transmission with attractive features in engineering applications.

Design and Theoretical Analysis of Highly Negative Dispersion-Compensating Photonic Crystal Fibers with Multiple Zero-Dispersion Wavelengths

This paper presents a highly negative dispersion-compensating photonic crystal fiber (DC-PCF) with multiple zero dispersion wavelengths (ZDWs) within the telecommunication bands. The multiple ZDWs of the PCF may lead to high spectral densities than those of other PCFs with few ZDWs. The full-vectorial finite element method with a perfectly matched layer (PML) is used to investigate the optical properties of the PCFs. The numerical analysis shows that the proposed PCF, i.e., PCF (b), exhibits multiple ZDWS and also achieves a high negative chromatic dispersion of −15089.0 ps/nm·km at 1.55 μ m wavelength, with the multiple ZDWs occurring within the range from 0.8 to 2.0 μ m range. Other optical properties such as the confinement loss of 0.059 dB/km, the birefringence of 4.11 × 10 − 1 , the nonlinearity of 18.92 W − 1 k m − 1 , and a normalized frequency of 2.633 was also achieved at 1.55 μ m wavelength. These characteristics make the PCF suitable for high-speed, long-distance optical communication systems, optical sensing, soliton pulse transmission, and polarization-maintaining applications.

Flexible beam delivery of ultrafast laser through vacuum-pumped anti-resonant hollow-core fiber

We demonstrate the transmission of a 100 MW-peak-power ultrafast laser through a 5-m anti-resonant hollow-core fiber (AR-HCF) with a pumpable armored tube for air exhaust. The AR-HCF consists of a 45-μm-hollow-core and seven untouched capillaries with an attenuation of 0.11 dB/m measured at a wavelength of 1030 nm. We investigate the effect of air-filling and vacuum pumping on transmission efficiency and pulse distortion. The comparison reveals the importance of controlling air concentration in hollow-core fibers (HCFs) for achieving high transmission efficiency and pulse quality. With the suppression of air concentration, the transmission efficiency increases from 61% to 72%, and pulse distortion is effectively controlled. The results demonstrate the potential of AR-HCFs for high-power ultrafast laser delivery systems for various applications. The pumpable armored tube design provides a simple and effective solution to suppress self-phase modulation (SPM) and enable flexible beam delivery.

Abstract P382: Blood Pressure Outcomes After 12 Months in Primary Care: A Prospective Cohort Study in Electronic Health Records Using Propensity Score Matching for Remote Patient Monitoring for Hypertension

Introduction: In primary care (PC) settings, more hands-on hypertension management may be enabled by remote patient monitoring (RPM) for blood pressure (BP), leading to greater BP control over time Hypothesis: Individuals prescribed RPM will have better BP control (BP &lt;140/90 mmHg) and lower office SBP after 12 months, compared with temporally-matched controls. Methods: We conducted a pragmatic matched cohort study in Medicare-enrolled patients with Hypertension at six PC practices, 288 of whom participated in pilot studies of a Omron VitalSight TM RPM system that enabled automatic transmission of BP and pulse into the electronic health record (EHR). We used 1:4 propensity score matching to identify 1152 contemporary matches for these patients from the same PC practices, based on age, sex, systolic BP (SBP), marital status, and several other clinical and healthcare visit characteristics. Outcomes after 12 months included controlling high blood pressure (most recent BP &lt;140/90 mm Hg), and most recent systolic BP and diastolic BP, assessed 1) using PC office measurements only and 2) incorporating RPM measurements. Results: The matched cohort of 1152 patients was, on average, 74 (SD 8) years old, 71% female, and 71% non-Hispanic white. Average baseline systolic BP (SD) was similar between groups: 142.7 (19.5) and 141.2 (18.7) mm Hg in RPM-prescribed patients and controls, respectively (Table). Compared with matched controls, after 12 months the RPM-prescribed cohort had greater BP control (72.6% versus 65.6%) and lower systolic BP (132.3 versus 136.6 mm Hg) when including RPM measurements. However, these metrics were similar when using PC office measurements only. Conclusions: Greater BP control and lower SBP were observed after 12 months in RPM-prescribed patients when considering RPM measurements. Further studies will assess the contributions of adherence to RPM use to observed declines in BP. The EHR can be used to prospectively construct and conduct cohort studies.

Efficient low-density grating setup for monochromatization of XUV ultrafast light sources.

Ultrafast light sources have become an indispensable tool to access and understand transient phenomenon in material science. However, a simple and easy-to-implement method for harmonic selection, with high transmission efficiency and pulse duration conservation, is still a challenge. Here we showcase and compare two approaches for selecting the desired harmonic from a high harmonic generation source while achieving the above goals. The first approach is the combination of extreme ultraviolet spherical mirrors with transmission filters and the second approach uses a normal-incidence spherical grating. Both solutions target time- and angle-resolved photoemission spectroscopy with photon energies in the 10-20 eV range but are relevant for other experimental techniques as well. The two approaches for harmonic selection are characterized in terms of focusing quality, photon flux, and temporal broadening. It is demonstrated that a focusing grating is able to provide much higher transmission as compared to the mirror+filter approach (3.3 times higher for 10.8 eV and 12.9 times higher for 18.1 eV), with only a slight temporal broadening (6.8% increase) and a somewhat larger spot size (∼30% increase). Overall, our study establishes an experimental perspective on the trade-off between a single grating normal incidence monochromator design and the use of filters. As such, it provides a basis for selecting the most appropriate approach in various fields where an easy-to-implement harmonic selection from high harmonic generation is needed.

Методика построения защищенных систем искусственного интеллекта для проведения электроретинографии в офтальмологии

Relevance. It is known that the method of electroretinography (hereinafter – ERG) in ophthalmology, which works on the key registration of changes in the bioelectric potential of the retina, uses the potential of exposure to light passing through the optical media of the eye. A similar method is conditionally applicable to the transmission of a light pulse over a fiber-optic cable, during which the correct transmission of information is carried out. If there is a violation or change in the electrical potential, there is every reason to believe that a person has any diseases. Purpose. To develop a technology for creating intellectual information security systems (IISS) is of a complex nature in which a quasi-biological paradigm is put in the first place, where the form of programming information processes, machine learning systems (MLS) and the construction of neural systems and ending with an AI architecture with built – in mechanisms for ensuring information security. Material and methods. In this article, a methodology for using a new artificial intelligence system (hereinafter referred to as AI) in a protected version for working with corrective devices for electroretinography in ophthalmology is compiled. Results. A set of methodological and scientific and technical solutions for the artificial intelligence system has been developed in order to ensure its «viability» and resistance to computer attacks aimed at violating the integrity. Conclusion. The article raises a key issue – the need to develop software architectural solutions for AI and adaptive neuro-fuzzy AI, which have «neurons» built into the software and hardware information protection systems with a universal set of commands for EG devices. Keywords: artificial intelligence, multi-agent system, electroretinography, neural network, integrity control, information security

Nonlinear field-control of terahertz waves in random media for spatiotemporal focusing.

Controlling the transmission of broadband optical pulses in scattering media is a critical open challenge in photonics. To date, wavefront shaping techniques at optical frequencies have been successfully applied to control the spatial properties of multiple-scattered light. However, a fundamental restriction in achieving an equivalent degree of control over the temporal properties of a broadband pulse is the limited availability of experimental techniques to detect the coherent properties (i.e., the spectral amplitude and absolute phase) of the transmitted field. Terahertz experimental frameworks, on the contrary, enable measuring the field dynamics of broadband pulses at ultrafast (sub-cycle) time scales directly. In this work, we provide a theoretical/numerical demonstration that, within this context, complex scattering can be used to achieve spatio-temporal control of instantaneous fields and manipulate the temporal properties of single-cycle pulses by solely acting on spatial degrees of freedom of the illuminating field. As direct application scenarios, we demonstrate spatio-temporal focusing, chirp compensation, and control of the carrier-envelope-phase (CEP) of a CP-stable, transform-limited THz pulse.

Influence of Nb2O5 Additive on Elastic and Dielectric Properties of NiCuZn Ferrites

The influence of Nb2O5 additive on elastic and dielectric properties of NiZnCu ferrite is reported. The longitudinal and shear wave velocities were measured by ultrasonic pulse transmission method. The elastic constants increased as the Nb2O5 contents increased. The dielectric parameters such as dielectric constant (ɛ′) and dielectric loss tangents as a function of frequency and Nb2O5 additive composition for all samples at room temperature. The variations in the dielectric constant (ɛ′) and dielectric loss tangents values were explained using Maxwell–Wagner interfacial polarization according to Koops phenomenological theory. AC conductivity was increased with an increase in the frequency. A reduction in AC conductivity with Nb2O5 additive is reported.

Propagation of an Ultrawideband Electromagnetic Pulse Along a Plasma-Filled Coaxial Line

The propagation of an ultrawideband (UWB) electromagnetic pulse along a coaxial line filled with a cold isotropic plasma is considered. The pulse shape evolution is studied both in the frequency domain through the Fourier transform analysis and in the time domain using either the high-frequency approximation or the finite-difference time-domain (FDTD) approach. The emphasis is placed on the behavior of the pulse shape for various values of the plasma density in the coaxial line. It is shown that transmission of a nanosecond TEM pulse in a plasma-filled coaxial line can serve for revealing the basic features of changes in the shape of such signals during their propagation in an unbounded plasma medium.

Wearable and Multifunctional Self-Mixing Microfiber Sensor for Human Health Monitoring

We propose a sensor based on the integration of self-mixing interference (SMI) with microfiber, for human health monitoring. Through the power variation of the reflected light from the microfiber which is embedded into polydimethylsiloxane (PDMS), we are able to accurately monitor pulse waves continuously and in real time, and human blood pressure is successfully monitored via the pulse transmission time (PTT). We measured systolic blood pressure (SBP) and diastolic blood pressure (DBP) in volunteers with a measurement error of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$- 0.222\,\,\pm \,\,2.636$ </tex-math></inline-formula> mmHg and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$- 1.056\,\,\pm \,\,2.198$ </tex-math></inline-formula> mmHg, respectively. Long-term health monitoring was also performed for several days, and measurements met the requirements of the American Association for the Advancement of Medical Instrumentation (AAMI). The experimental results show that the sensor is capable of accurately monitoring multiparameter information of human pulse and blood pressure, and has the characteristics of high sensitivity, noninvasive, and long-term monitoring. This application of microfiber to the self-mixing sensor provides an effective solution for smart health monitoring, and has potential applications in disease prevention and healthcare.

Parameter extraction of 3D acoustic images using a nonlinear optimization technique

In biometrics, classification techniques are based on parameter extraction from a large data set, such as fingerprints. Specifically, when using 3D acoustic images, it is necessary to extract a set of meaningful parameters. This work assumes that each significant target will have an acoustic image characterized by the 2D radiation pattern of the array and the envelope of the transmission pulse used. Under this assumption the final acoustic image can be synthesized by a linear combination of the significant targets in the scene. The work uses a non-linear optimization algorithm that obtains the parameters (power, range, elevation and azimuth) for each of the significant targets from a 3D acoustic image. Specifically, the algorithm is applied to the parameterization of 3D images of people, as a prior step to the use of classification algorithms based on machine learning.

Information embedding in DFRC networks through chirp waveform diversity

We consider a dual function radar communications network and propose a waveform diversity-based approach to embed both target and scheduling data in the transmitter pulses. The scheduling data of radar signal bandwidth, carrier frequency, and waveform along with the information on target detection, range, and Doppler are shared among the network radar nodes without a need for designated communication links. Scheduling and target information are encoded to bits and transmitted over the radar coherent processing interval using up- and down-chirps. We derive exact expressions of probability of bit error and false alarm rate for sharing scheduling and target information data between two radar nodes. The effect of different parameters and data sharing on the radar performance is analyzed and validated by computer simulations. Using the cross-ambiguity function, we show the capability of the up- and down- chirp sequence transmission scheme in reducing range sidelobes compared to the conventional transmission of only the up- (or down-) chirps. To overcome the limited data rate associated with only using two chirp waveforms, we consider orthogonal chirp division multiplexing and derive its CAF. We demonstrate the suitability of OCDM for high data rate radar operations by examining the mainlobe width and sidelobe levels of the zero-Doppler and zero-delay cuts of the CAF.