Shape Of Signal Research Articles

Saltire: a model to measure dynamical masses for high-contrast binaries and exoplanets with high-resolution spectroscopy

ABSTRACT High-resolution cross-correlation methods are widely used to discover and to characterise atomic and molecular species in exoplanet atmospheres. The characteristic cross-correlation signal is typically represented as a function of the velocity of the system, and the semi-amplitude of the planet’s orbit. We present Saltire, a fast and simple model that accurately reproduces the shape of such cross-correlation signals, allowing a direct fit to the data by using a minimum set of parameters. We show how to use this model on the detection of atmospheric carbon monoxide in archival data of the hot Jupiter $\rm \tau$ Boötis b, and how Saltire can be used to estimate the semi-amplitude and rest velocity of high brightness ratio binaries. By including the shape of the signal, we demonstrate that our model allows to robustly derive the signal position up to 10 times more accurate, compared to conventional methods. Furthermore, we discuss the impact of correlated noise and demonstrate that Saltire is a robust tool for estimating systematic uncertainties on the signal position. Saltire opens a new door to analyse high signal-to-noise data to accurately study atmospheric dynamics and to measure precise dynamical masses for exoplanets and faint stellar companions. We show that the phase-resolved shape of the atmospheric cross-correlation signal can accurately be reproduced, allowing studies of phase-dependent signal changes and to disentangle them from noise and data aliases.

Extracellular molecular signals shaping dendrite architecture during brain development.

Proper growth and branching of dendrites are crucial for adequate central nervous system (CNS) functioning. The neuronal dendritic geometry determines the mode and quality of information processing. Any defects in dendrite development will disrupt neuronal circuit formation, affecting brain function. Besides cell-intrinsic programmes, extrinsic factors regulate various aspects of dendritic development. Among these extrinsic factors are extracellular molecular signals which can shape the dendrite architecture during early development. This review will focus on extrinsic factors regulating dendritic growth during early neuronal development, including neurotransmitters, neurotrophins, extracellular matrix proteins, contact-mediated ligands, and secreted and diffusible cues. How these extracellular molecular signals contribute to dendritic growth has been investigated in developing nervous systems using different species, different areas within the CNS, and different neuronal types. The response of the dendritic tree to these extracellular molecular signals can result in growth-promoting or growth-limiting effects, and it depends on the receptor subtype, receptor quantity, receptor efficiency, the animal model used, the developmental time windows, and finally, the targeted signal cascade. This article reviews our current understanding of the role of various extracellular signals in the establishment of the architecture of the dendrites.

Design and construction of an Ultrasounographic Device Dedicated to the Parietal Rheology Measurement in Human Carotid Artery

We present in this article a detection system of ultrasounographic signal (USG) dedicated to the measurement of parietal rheology in human carotid artery. The aim of this practical work is to develop an ultrasonic method capable of visualizing the localized velocity profile of the carotid artery wall. The device produced makes it possible to take the USG signal from carotid wall of the human neck. It comprises an ultrasonic contact probe applied during the measurement (sensor), a signal shaping circuit, an acquisition and digitization interface in conjunction with an RS232 serial communication port and a local computer terminal hosting a graphical user interface (GUI) implemented in Visual Basic integrated development environment enabling the display, archiving and the digital processing of parietal ultrasonic signal. The aim of this study is to reconnoitering the possibility of using ultrasound for a continuous and non-invasive measurement of the arteries parietal rheology. In this work, a sensor of ultrasound is used to measure the movement and the speed of the carotid artery wall, an image of the arteries parietal rheology.

Simulated Surface Electromyographic (SEMG) Signal Generation and Detection Model

Abstract For didactic purposes, the aim of this work was to improve a simulation model of surface electromyographic (sEMG) signal by taking into consideration the shortcomings of previously developed models. This model started with the simulation of the single fibre action potential (SFAP), then the model of the single motor unit action potential (MUAP), afterwards the imitation of the train of MUAP and finally the modellig of the resultant sEMG signal which is the sum of the MUAPs trains. SFAP simulation was based on: i) the description of the volume conductor model which is composed of four layers (bone, muscle, fat and skin), ii) the description of the electrodes shapes and sizes as well as spatial filters, iii) and the transmebrane current. The proposed model shows its effectiveness in the possibility of carrying out practical work by simulation on the modelling of SFAP, MUAP, MUAPT and the sEMG signal. The most important result of this model is that signal processing tools can be applied to analyze and interpret real-world phenomena such as the effects of physiological, non physiological and sensing system parameters on the shape of the simulated sEMG signal.

Scheduling-Based Transmit Signal Shaping in Energy-Constrained Molecular Communications

Scheduling-Based Transmit Signal Shaping in Energy-Constrained Molecular Communications

The Advantages of Global Photometric Models in Fitting Transit Variations

Estimation of planetary orbital and physical parameters from light-curve data relies heavily on the accurate interpretation of Transit Timing Variation (TTV) measurements. In this letter, we review the process of TTV measurement and compare two fitting paradigms—one that relies on making transit-by-transit timing estimates and then fitting a TTV model to the observed timings, and one that relies on fitting a global flux model to the entire light-curve data set simultaneously. The latter method is achieved either by solving for the underlying planetary motion (often referred to as “photodynamics”), or by using an approximate or empirical shape of the TTV signal. We show that, across a large range of the transit S/N regime, the probability distribution function of the mid-transit time significantly deviates from a Gaussian, even if the flux errors do distribute normally. Treating the timing uncertainties as if they are distributed normally leads, in such a case, to a wrong interpretation of the TTV measurements. We illustrate these points using numerical experiments and conclude that a fitting process that relies on a global flux fitting, rather than the derived TTVs, should be preferred.

Analytical estimation of the signal to noise ratio efficiency in axion dark matter searches using a Savitzky-Golay filter

The signal to noise ratio efficiency ϵSNR in axion dark matter searches has been estimated using large-statistic simulation data reflecting the background information and the expected axion signal power obtained from a real experiment. This usually requires a lot of computing time even with the assistance of powerful computing resources. Employing a Savitzky-Golay filter for background subtraction, in this work, we estimated a fully analytical ϵSNR without relying on large-statistic simulation data, but only with an arbitrary axion mass and the relevant signal shape information. Hence, our work can provide ϵSNR using minimal computing time and resources prior to the acquisition of experimental data, without the detailed information that has to be obtained from real experiments. Axion haloscope searches have been observing the coincidence that the frequency independent scale factor ξ is approximately consistent with the ϵSNR. This was confirmed analytically in this work, when the window length of the Savitzky-Golay filter is reasonably wide enough, i.e., at least 5 times the signal window.

PULMONARY SOUND DESIGN USING MAX 9814 SENSOR WITH NEXTION VIEW

This study aims to develop a tool that can assist nurses in examining patients by displaying sounds and signals on a TFT LCD screen. This tool uses the MAX 9814 sound sensor, which converts sound into an electrical signal. This sensor will generate a voltage when the diaphragm inside it moves back and forth. To design this tool, researchers used a series of high pass filters and low pass filters with a cut-off frequency of 333 Hz - 714 kHz. During testing of this tool using the MAX 9814 sensor mounted on a stethoscope, the signal appears stable on the TFT LCD screen and sound can be played properly. However, if the placement of the stethoscope is not correct during the examination, this can also affect the signal and sound produced. This tool should not produce a clear and loud sound when checking, because if this happens, the inspection cannot be carried out optimally. This research also produces a signal shape that is almost similar to the signal on the phantom. It is important to note that the MAX 9814 can work optimally if it is not exposed to environmental noise. Therefore, if this equipment is used in a noisy environment, the signal and sound produced may be disturbed by environmental noise. This research was conducted with the aim of making it easier for doctors and nurses to carry out portable examinations, as well as to monitor signals and sounds easily.

Tribological evaluation of electric vehicle driveline lubricants in an electrified environment

Electrification continues to permeate the automotive industry, with future projections showing an exponential growth in the market share for both light and heavy-duty applications. Existing test methods for automotive applications were developed to model internal combustion engine vehicles and drivelines and are not appropriate for electric drivelines that experience stray electric currents. Tribometers can be used to evaluate friction and wear on modeled surfaces simulating in-vehicle operation. In this work, a commercially available tribometer was modified to isolate an electrical input into a tribological contact. After necessary modifications to the tribometer, a test matrix was completed for investigating different temperatures, load conditions, speed conditions, voltage input types, frequencies of AC signal, and shapes of AC signal. These parameters were tested on three lubricants—two typical automatic transmission fluid formulations and gear oil used in differential applications. Friction was measured throughout the tests, and wear scar width was measured at the end of each test. Results indicated that temperature, DC voltage, AC frequency, lubricant, and test profile had statistically significant differences in wear scar width. For electrical parameters, AC frequency produced different results from DC voltage when no voltage was applied. This significance applied to only one lubricant, with the other two lubricants having mixed results.

Precision Measurement of the Group Velocity of Ultrasound in Samples with Millimeter Thickness

A methodology is proposed for high-precision local measurement of the group velocity of longitudinal waves in solid samples with millimeter thickness. Achievement of the required accuracy involves laser thermo-optical excitation of submicrosecond ultrasonic video pulses and ultrawideband piezoelectric recording of acoustic signals reflected from the test sample. Plane-parallel samples made of duralumin, quartz, and steel with a thickness of 2–6 mm are studied. To achieve the required accuracy in measuring the group velocityof ultrasound, the signal shape is mathematically processed with compensation for diffraction of the ultrasonic beam as it propagates through the sample. The possibility of ensuring the uncertainty in measuring the group velocity of ultrasound in the 1–15 MHz frequency range at a level of 0.1% in samples with millimeterthickness is demonstrated.

A novel method for the whole-cell detection of environmental microorganisms using hemin and tyramide signal amplification (Hemin-TSA) with a desired fluorescent dye

A method called hemin-tyramide signal amplification (Hemin-TSA) was developed for visualization of environmental microorganisms using hemin and tyramide signal amplification. In Hemin-TSA, hemin, which has peroxidase activity, is bound to microbial cells, and a desired fluorescent dye is deposited on the microbial cells by a hemin-catalyzed TSA reaction. The protocol was initially optimized in terms of hemin concentration, hemin binding time and repeated reaction times of TSA. Hemin-TSA showed a comparative or improved signal-to-noise ratio compared to DAPI staining. The shapes of fluorescent signals obtained from microbial cells were almost morphologically identical to those observed in phase contrast microscopy. Hemin-TSA staining provided more accurate cell counts than DAPI staining, especially for actively growing cells, for which two or three spotty DAPI signals were obtained from a single cell. In addition, microbial cells that were not detected by DAPI staining were detected by Hemin-TSA with fluorescein, which enabled us to avoid high non-specific fluorescence under UV excitation. The method developed in this study allows us to visually detect microbial cells in various environments with the characteristics of better cell morphological identification, improved enumeration accuracy and selectivity of fluorescent dyes.

Development of hard x-ray photoelectron spectroscopy using synchrotron radiation x-ray up to 30 keV.

Hard X-ray photoelectron spectroscopy (HAXPES) is a powerful tool for investigating the chemical and electronic states of bulk and buried interfaces non-destructively due to its large probing depth. To obtain a much larger probing depth and measure deeper regions than conventional HAXPES, we have developed a high-energy HAXPES (HE-HAXPES) system excited by photon energies up to 30keV. This system is achieved by combining an applied bias voltage on the sample with a conventional hemispherical electron energy analyzer. By utilizing this system, we successfully observed a Si 1s peak from the bulk-Si substrate underneath the 110-nm-thick SiO2 film at a photon energy of 30keV. Moreover, the system found that the asymmetrical spectral shape of the Si substrate signal originated from the electronic state, which is upward band bending formed at the interface between the SiO2 film and Si substrate. The HE-HAXPES system, excited by photon energy up to 30keV, could be a very useful tool to yield genuine insights into the chemical and electronic states in deeply buried regions.

Decision criteria in signal detection model are not based on the objective likelihood ratio.

How people set decision criteria in signal detection model is an important research question. The likelihood ratio (LR) theory, which is one of the most influential theories about criteria setting, typically assumes that (a) decisions are based on the objective LR of the signal and noise distributions, and (b) LR criteria do not change across tasks with various difficulty levels. However, it is often questioned whether people are really able to know the exact shape of signal and noise distributions, and compute the objective LR accordingly. Here we suggest whether decision criteria are set based on objective LR can be tested in two-condition experiments with different difficulty levels across conditions. We then asked participants in three empirical experiments to perform two-condition perceptual or memory tasks, and give their answer using confidence rating scale. Results revealed that the two assumptions of LR theory contradicted with each other: if we assumed decision criteria were based on objective LR, then the estimated LR criteria differed across difficulty levels, and fanned out as task difficulty decreased. We suggest people might inaccurately estimate the LR in signal detection tasks, and several possible explanations for the distortion of LR are discussed. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

CONFIGURATIONS OF ULTRASONIC EMITTER RESONANCE MODES FOR UNILATERAL ACCESS TO AN OBJECT

Link for citation: Azin A.V., Bogdanov E.P., Vasilyev A.V., Ponomarev S.A., Ponomarev S.V., Rikkonen S.V. Configurations of ultrasonic emitter resonance modes for unilateral access to an object. Bulletin of the Tomsk Polytechnic University. Geo Аssets Engineering, 2023, vol. 334, no. 10, рр. 199-209. In Rus. Relevance. To prepare high-viscosity oil for transport, a number of methods are used in practice: thermal, chemical and the method of physical influences. Ultrasonic exposure of hydrocarbon raw materials is one of the physical methods. It is necessary to develop an effective method for tuning an ultrasonic emitter for maximum energy transfer into a multilayer technological medium. Aim: to study resonant operating modes of an ultrasonic emitter in a multilayer system with unilateral access to the object with simplified design of a resonance type ultrasonic emitter. Objects: oscillating system of an ultrasonic resonant type emitter, multilayer system, physical model of a system «ultrasonic emitter – multilayer system». Methods: mathematical modeling of linear oscillating system to determine the properties of oscillating system influence and technological factors on the form of vibration oscillations and on the amplitude-frequency characteristics of the system; experimental research on the basis of the physical model «ultrasonic emitter – multilayer system». Results. The authors have revealed a physical feature of the oscillatory system operation, which consists in the fact that at resonance the form of oscillations of the force signals of a multilayer piezoactor and vibration acceleration signals are purely harmonic in nature. This effect extends to operation of a resonant-type ultrasonic emitter in a short-circuit mode on a multilayer system. It was found that force and vibration acceleration amplitude-frequency characteristics of a multilayer piezoactor are similar to each other. Based on the analysis of theoretical and experimental data, the authors developed the method for adjusting the resonant operating modes of an ultrasonic emitter with unilateral access to an object. This allows simplification and reduction in the emitter design cost. The method for setting up oscillatory systems is applicable for laboratory and industrial installations. Conclusion. The research results show that in practice, harmonic shape of acceleration and force signals, as well as force amplitude of a multilayer piezoactor can be used as criteria for determining and adjusting the resonance of an oscillatory system. The oscillatory system of a resonant-type ultrasonic emitter can be tuned to resonance according to the shape and amplitude of the signal from the force sensor of the multilayer piezoactor. The force sensor is located in series with the multilayer piezoactor and does not require additional structural elements for its fastening. The ultrasonic emitter design is greatly simplified due to the absence of a vibration acceleration sensor. The method of adjusting the resonance of an oscillatory system using only a force sensor is also applied when operating a resonant-type ultrasonic emitter to a multilayer mechanical system. The developed design and technique for tuning the oscillatory system of a resonant-type ultrasonic emitter can be conveniently used when influencing process fluids through the walls of tanks and storage tanks.

Оценка точности цифровой обработки сильно зашумленных сигналов с помощью эвристических алгоритмов

Heuristic algorithms are often used as an alternative when solving problems of high computational complexity or lacking an exact solution, allowing to quickly obtain the desired result. Usually, they do not have a strict mathematical justification, but their application is justified in terms of practicality. Formally, algorithms that use approximate methods can be classified as heuristic. However, when applying them, the problem of determinism lack is often arises, which does not always allow one to evaluate the solution obtained accuracy. The paper considers a methodical approach to assessing the accuracy of heuristic algorithms designed to determine the useful signal shape and parameters on the strong noise component background. It is based on the method of analogy and consists in modeling an artificial signal with given parameters and a background noise interference similar in its characteristics to additive white Gaussian noise. In this case, the noise component is formed by software using a pseudo-random number sequence generator. Such generators are included in the packages of almost all high-level programming languages built-in functions. A comparative analysis of the real and artificial noise characteristics is presented, that shown the problem solving by numerical modeling possibility. The results of accuracy estimation in determining the artificial signal parameters, that is separated from the noise component using piecewise linear approximation and averaging heuristic algorithms, are obtained. The problem of empirical data smoothing with the discrete signal equivalent replacement by a quadratic functions whose parameters provide a piecewise parabolic approximation its shape is also considered. This procedure eliminates the residual signal bounce that inevitably occurs as a result of linearization and allows further recording at any sampling rate. Thus, the proposed approach allows us to quantify the accuracy of heuristic algorithms used in determining the expected signal parameters.

Diagnostic development using net analyte signal for pure component modeling approaches

The use of calibration-free or minimal calibration chemometric modeling approaches has garnered increased interest as the application of process analytical technologies (PAT) has expanded in the pharmaceutical industry. Pure component models such as iterative optimization technology (IOT) algorithms require only pure component spectra and no mixture samples as model inputs. However, the deployment of pure component models for PAT is limited by the lack of model diagnostics to establish confidence in model predictions and identify outliers. In the presented research, a novel diagnostic for use with IOT, called NAS-T, is proposed based on comparing the shape of net analyte signals (NAS) between the pure components and a sample mixture. Circular statistics were used in the analysis of NAS-T. The new diagnostic was applied in parallel with the partial least squares (PLS) Hotelling's T2 diagnostic to identify outlier near-infrared spectral samples from a set of pharmaceutical powder mixtures. The outliers detected by the NAS-T diagnostic included both chemical interferences (contamination) and physical interferences (process variations). Preprocessing the mixture sample spectra produced trends in the model diagnostics that were consistent between IOT and PLS. These results support the adoption of IOT and other pure component models for PAT applications in the pharmaceutical industry.

Height measurement accuracy improvement due to the shape of envelope echo signal

Height measurement accuracy improvement due to the shape of envelope echo signal

Tomography analysis of Al–Mg alloys manufactured by wire-arc directed energy deposition with different metal transfer modes

The interest in aluminum-magnesium alloy additive manufacturing through Wire-arc Directed Energy Deposition (DED) technology has substantially grown in recent years. The main challenge in additive manufactured aluminum-magnesium alloys is the occurrence of porosity. In this context, Gas Metal Arc Welding (GMAW) based additive technology is suitable for aluminum printing as it allows high deposition rates and reduces porosity levels through alternative metal transfer modes without adding any extra equipment. Therefore, this research explores the effects of these alternative metal transfer modes, which determine the current signal shape and polarity, on the distribution and morphology of micropores using X-ray computed tomography in both single-bead and double-bead walls. The novelty of this paper lies in the comparison of the porosity obtained using alternative transfer modes, which, unlike CMT (Cold Metal Transfer) modes, have not been exhaustively analyzed. Additionally, to date, there has been no comprehensive comparison of the porosity results obtained in single walls and overlapped walls. The results demonstrate that pulsed-AC transfer mode with a current signal featuring variable polarity yields acceptable porosity fraction values of less than 0.04% in single-bead walls and less than 0.01% in double-bead walls, achieving high productivity.

Photomultiplier tube signal conditioning for high-temperature applications

Abstract Ionizing radiation detection in harsh environment conditions often requires additional signal processing to match the requirements of the commercial data readout systems. The subject of this paper is the design of the high-temperature (HT) signal conditioning module that ensures the applicability of scintillation detectors that utilize photomultiplier tubes (PMT) with moderate sampling rate instrumentation. The design was developed for the operation in HT environments (up to 120°C). In order to achieve the optimal signal shape, the module combines a charge amplifier and a low-pass filtering circuitry. An embedded power supply section makes it a complete, standalone unit requiring a single 12 V supplying line. A comprehensive analysis of the developed device, named “PreAmp Shape”, was conducted in order to prove the intended functionality over the different working conditions.

Analyses of unpredictable properties of a wind-driven triboelectric random number generator

Wind-driven triboelectric nanogenerators (W-TENGs) are a promising candidate for an energy harvester because wind itself possesses unexhausted, ubiquitous, and clean properties. W-TENG has also been used as a random number generator (RNG) due to the inherent chaotic properties of wind that is also an entropy source. Thus, a W-TENG which simultaneously generates both power and true random numbers with a two-in-one structure, is a wind-driven RNG (W-RNG) like the Janus. However, a root cause of W-RNG unpredictability has not been elucidated. In this work, the unpredictability, which is essential and critical for an RNG, is statistically and mathematically analyzed by auto-correlation, cross-correlation, joint entropy, and mutual information. Even though the overall shape of the total output analog signals from the W-RNG looks like a sinusoidal wave that is not obviously unpredictable, discretized digital signals from the continuous analog output become unpredictable. Furthermore, partial adoption of 4-bit data from 8-bit raw data, with the aid of analog-to-digital converter hardware, further boosts the unpredictability. The W-RNG, which functions as a W-TENG, can contribute to self-powering and self-securing outdoor electrical systems, such as drones, by harvesting energy and generating true random numbers.