Acceleration Measurements Research Articles

Model for Determining Earth's Gravitational Acceleration on a Mathematical Pendulum

Gravity is an accelerating property of the earth that causes objects to fall freely. The acceleration of gravity is not the same at every place on the Earth's surface. To measure the Earth's gravity (small g), scientists can use various techniques, such as dropping a mass from a certain height and measuring the time it takes to fall to the ground or using a mathematical pendulum to measure the period of oscillation and use it to calculate the acceleration due to gravity. In this paper, a study of the mathematical pendulum in the measurement of the Earth's gravitational acceleration is conducted, and the measurement experiment is illustrated. Method To measure the length of the pendulum, you must have a ruler, meter stick, or tape measure. At the top end of the string, start the measurement at the point where the string rotates out of place. Then, measure up to the center of the pendulum, which is the object hanging on the string. From the results of this study, it can be concluded that the value of the period of a pendulum is affected by several factors, including the length of the rope used and the angle of initial deviation, while the factors that do not affect the period are the mass and diameter of the pendulum.

Measurement of Acceleration Due to Gravity Using Arduino

The undertaken research paper is an easy experiment based on Arduino was constructed in order to investigate the acceleration of the object while it was falling freely and to estimate the value of "g" (the acceleration that is generated by gravity). The reseach aimed to achieve three objectives through this research: first, to comprehend the manner in which airborne gravity gradiometers synthesise gravity fields using residual terrain modelling and the equivalent source layer method; second, to evaluate the durability of systems based on Arduino in various environments; and third, to contrast the accuracy, efficiency, and user-friendliness of these systems with those that are more conventional. The investigation of the acceleration due to gravity measurement using Arduino was conducted using secondary sources, which include books, websites, academic papers, newspapers, and magazines. These sources are not directly comparable. The evaluation and severity determination of a diverse array of research topics are facilitated by this explanatory research approach to the analysis of the conceptual components. The result of the study implies that in order to obtain distance time curves, readings realted to gravity is made at a variety of intervals throughout the course of application of the traditional kinematic equations made it possible to compute the acceleration that happened during the free fall. There has been found to be a good agreement between “the shape of the distance-time graphs” that were gathered from the secondary setup and the graphs that were expected, and the values of g that were calculated were within the range that was anticipated. It has been further discovered that the magnitude of gravitational acceleration is 9.805 metres per second squared after a series of research study were carried out.

A broken-track association method for robust multi-target tracking adopting multi-view Doppler measurement information

Due to reasons such as target maneuvering and track crossing, mistaken track association may be caused. When the target is in Doppler blind zone, it often leads to the loss of measurement information, which is reflected in the situation as track breakage. In response to the demand of track repair in the case of track breakage, we propose a robust multi-target broken-track association method that comprehensively utilizes multi-view Doppler measurement information. Firstly, based on the derivation of measurement coordinate transformation bias, the multi-sensor Doppler measurement after error correction is fused to obtain the heading velocity and heading acceleration measurement of the target. Secondly, the multi-scan association cost function based on the heading velocity and heading acceleration measurement is constructed, and the optimal correlation sequence is obtained by minimizing the complexity of the cost function. Then, for the case of missing measurements, the optimal association sequence is used to extrapolate the missing measurements, thereby accomplishing the correlation among the broken track segment, the extrapolated measurement and the optimal correlation sequence. Thirdly, we design a multi-scan GLMB smoother to perform forward prediction and backward smoothing on the above correlation results to improve the smoothness of the track. Simulation and actual experimental results suggest that our proposed method can effectively deal with the track breakage situation of dense targets, particularly in track integrity, track accuracy and robustness compared with the existing approaches.

Experimental investigation of vortex rope mitigation in a 10 MW axial turbine

Increased utilization of hydraulic turbines as a regulatory tool for electrical grid stabilization forces some turbines to operate away from their design point, thus increasing wear and tear. In here, rotating vortex rope (RVR) mitigation by means of radial insertion of cylindrical rods in the draft tube is investigated experimentally on a 10 MW Kaplan turbine operating as a propeller. Pressure measurements in the draft tube, runner chamber and spiral casing, along with strain and acceleration measurements on the turbine shaft are performed to scrutinize the effectiveness of the mitigation system. Three part-load operating points are investigated, corresponding to 83 %, 72 %, and 68 % of the guide vane servo stroke relative to the best-efficiency point opening. It is shown that the mitigation system dampens the harmful effects of the vortex rope at all operating points, especially at lower part-load conditions. Specifically, the pressure amplitude of the RVR fundamental mode inside the runner chamber reduces by 84 %, 63 %, and 73 % at the three investigated operating points, relative to the amplitudes without mitigation. On the turbine shaft, the fundamental mode of the axial thrust oscillations at the RVR frequency reduces by 65 %, 83 %, and 95 %. It is shown that the mitigation does not come with a high cost on the turbine time-averaged efficiency over the course of the measurements, the penalty being 2 %, 2.5 %, and 3.2 % at the protrusion length where optimal mitigation is achieved at each operating point. For high-head machines, the penalty is expected to be lower since the relative importance of the draft tube diminishes for higher heads.

Assessment of Hoisting Conveyance Guiding Forces Based on Field Acceleration Measurements and Numerical Simulation

Shafts play a key role in the operation of mining plants. They connect underground excavations with the surface and provide the ability to transport people, equipment, and raw materials. The nature of the dynamic interaction of a conveyance moving at a significant speed along deformed guide rails is complex, and the method of assessing the interaction of hoisting conveyances with shaft steelwork, despite ongoing research, still requires further understanding and improvement. Misalignments of the guide rails and conveyance movements transverse to the shaft axis induce impact (guiding) forces, which are the key design parameters of shaft steelwork. The reliable assessment of guiding forces allows the design of safe and economical steelworks and the assessment of their structural safety during operation under deformations and corrosive deterioration. Determining the value of guiding forces requires their field measurements or the use of approximate empirical formulas. Both methods have their limitations—measurement is expensive and interferes with normal shaft operation, while empirical formulas are subject to high error due to the lack of consideration of many structural details specific to each shaft that significantly affect the behavior of the system. This study presents a new method for using a relatively simple-to-implement measurement of hoisting conveyance acceleration to assess guiding forces. A finite element model of the skip and steelwork was built, and simulations of the conveyance interaction with the structure were carried out. A strong relationship between the sliding plate’s impact point location and the guiding force was found. Extreme values of the guiding force were observed in the vicinity of the bunton connection. The study showed that reducing the skip load mass does not affect the force value. Simplified methods of calculating the moments of inertia of the hoisting conveyance significantly overestimate the code-based values of the guiding forces. The presented method considers the actual stiffness and mass distribution of hoisting conveyance and, therefore, allows for a more accurate estimation of the guiding forces and the transport of larger loads. This data-driven approach allows for the continuous monitoring of the guiding forces, the adjustments of the hoisting parameters, the rational planning of repairs, and a reduction in the replacement of corroded shaft steelwork.

A wide-frequency triboelectric vibration sensor for self-powered machinery health monitoring

Abnormal vibration is usually a precursor to structural damage and performance degradation industrial equipment and transportation. Vibration detection at critical locations such as electrical motors and bearings within large equipment has emerged as an indispensable method for machinery health monitoring. Current vibration detection instruments mostly need to be powered by cables or batteries, which has application limitations in complex moving equipment and restricted space. In this paper, a disc-like triboelectric nanogenerator (DL-TENG) with a multi-sized honeycomb structure is proposed as an innovative solution for achieving wide band and high precision acceleration detection of the vibration. Multi-diameter polytetrafluoroethylene (PTFE) balls are used as friction materials to achieve the high voltage output of the TENG, providing sufficient energy for the detection circuit. By carefully designing suitable honeycomb structures for PTFE balls of different diameters, the ability to detect broadband vibration signals is obtained. The experimental results demonstrate that DL-TENG with honeycomb structure and multi-size PTFE balls can detect acceleration signals ranging from 10 to 2000 Hz, and the acceleration measurement range can reach 1–11 m/s2 with an acceleration resolution of 0.1 m/s2. Moreover, DL-TENG can output more than 80 V peak-to-peak under vibration conditions of 11 m/s2. And under vibration conditions of 8 m/s2, the DL-TENG can fully charge a 100 μF capacitor to 5 V in just 100 seconds. By equipping a special circuit for DL-TENG, wireless self-powered vibration detection is realized. This study is expected to be applied in the scenario of vibration information collection in complex ring vibration environment and provides a new paradigm for the realization of self-powered vibration sensors.

Abstract 4145812: Cardiovascular MRI-Derived Cardiac Age Acceleration is Associated with Shortened Leukocyte Telomere Length But Not Clonal Hematopoiesis of Indeterminate Potential

Introduction: Cardiac structure and function typically decline with age. Abnormal acceleration of this decline, known as cardiac age acceleration, can be estimated from MRI using deep learning. Both general and cardiac-specific mechanisms may contribute to cardiac aging. Longer telomere length in circulating leukocytes, which indicates greater cellular capacity for replication, has been associated with a lower risk of heart failure and more favorable cardiac structure and function Recent data have also suggested that longer telomeres contribute to risk of clonal hematopoiesis of indeterminate potential (CHIP), which has been linked to increased risk of atherosclerosis, heart failure and arrhythmia. Here we studied whether telomere length or CHIP status are associated with deep learning derived cardiac age acceleration. Methods: We developed a deep learning model to estimate cardiac age acceleration in 70,805 UK Biobank participants from the cardiovascular MRI (four-chamber long axis view). Of these, we identified leukocyte telomere length (LTL) in 61,554 and were able to evaluate CHIP in 61,636. In an additional 372,465 participants unrelated to those with imaging, a genome-wide association study (GWAS) was conducted for LTL, and a GWAS of cardiac age acceleration was conducted in those with imaging; using these, a two-sample Mendelian randomization (MR) was performed to identify putatively causal relationships. Results: In the 61,636 participants with both CHIP and cardiac age acceleration measurements, CHIP was not associated with cardiac age acceleration regardless of driver gene (p=0.79). In contrast, cardiac age acceleration was associated with a shorter LTL (Beta=-0.025 SD, p=5.4E-10). Shorter LTL was causally associated with cardiac age acceleration (Beta=-0.10, p=0.047). Conclusions: These data suggest that general aging mechanisms conferred by shortening telomeres may contribute to the age-associated structural and functional decline of the heart as observed with MRI. In comparison, the relationship between CHIP and cardiovascular risk may not manifest in ways that cause apparent cardiac age acceleration.

Accelerated strategies for impact identification of composite laminate using sparse sensor networks and model-based virtual time reversal

Barely visible impact damages are notorious threats to the health of composite structures. Detection of the impact is critical to promise the performance of composite structures. Recently, the authors proposed an impact identification method based on sparse sensor networks and virtual time reversal, which is verified on composite laminates. However, the computational demands of virtual time reversal simulations pose a notable limitation to this approach. To improve the efficiency of the method, several acceleration measures are developed in this article. First, the re-emitted wavefield analysis is accelerated using a frequency-domain method rather than the time-domain simulation, which largely reduces the computational costs. Subsequently, the GPU parallel acceleration algorithm is configured to further improve the efficiency. The proposed acceleration strategy is experimentally validated by various impact events on a composite laminate. The results render that the proposed acceleration strategy can promise the accuracy of the results of impact identification while significantly promoting computational efficiency, in which the time consumption plummets to only 1.94 s. Moreover, factors affecting the efficiency of the proposed method are discussed. The time consumption is positively correlated with the number of sensors involved in the identification. In addition, as the number of candidate points increases, the GPU encounters difficulty in handling all complex matrix operations simultaneously, leading to a substantial rise in computation time. Furthermore, the effect of signal lengths on the efficiency is minimal and largely negligible.

Diagnostic Value of Maximal Systolic Acceleration Measurements in the Follow-up of Complex Endovascular Aortic Repair: Illustration of a Concept.

After complex endovascular aortic repair (cEVAR), long-term surveillance is advocated to monitor for potential (stent-related) complications. Although various imaging modalities are used, computed tomography angiography remains the standard in current clinical practice worldwide. However, radiopaque markers can cause metal artifacts and scattering, hampering assessment of patency of side branches. The maximal systolic acceleration (ACCmax) is a relatively new duplex ultrasound (DUS) parameter measured distal to a stenosis, avoiding in-stent assessment and scattering. The aim of this article is to illustrate the potential diagnostic utility of the ACCmax after cEVAR and visceral artery stenting in general. The ACCmax is measured at the maximal slope of the upstroke during the systolic phase in arterial flow. By manually connecting 2 points, a tangent line is created in which the maximal acceleration is automatically calculated and expressed in m/s2. A higher value reflects better arterial perfusion proximal to its measurement point. One measurement of a visceral artery takes about 5 minutes. ACCmax measurements can be a useful addition during DUS follow-up after cEVAR or visceral artery stenting, possibly decreasing radiation exposure, nephrotoxicity, and health care costs. Long-term surveillance after complex endovascular aortic repair (cEVAR) is necessary to monitor for potential (stent-related) complications. Although CTA is the most common modality for imaging, metal artifacts and scattering can hamper the assessment of stent patency. The maximal systolic acceleration (ACCmax) is a duplex ultrasound based parameter that reflects arterial perfusion proximal to its measurement point. Due to its noninvasive nature, it can be a useful addition during follow-up after cEVAR or visceral artery stenting, possibly decreasing radiation exposure, nephrotoxicity and health care costs as well.

Origami-Inspired Collapsible Structures for Small Rotorcraft Collision Resilience and Landing

Abstract This article reports on the design, fabrication, and testing of flexible, collapsible structures inspired by origami and kirigami that can be used to protect small rotorcraft from collision impacts and to serve as landing gear. Twenty structures created from variations of Pako Pako, Magic Ball, and Herringbone fold patterns were laser cut from cardstock and evaluated experimentally. Some of the Pako Pako structures were designed to have graduated mechanical stiffness. An empirical procedure based on acceleration measurements has been developed that enables quantitative evaluation of each structure based on the characterization parameters of peak acceleration, peak velocity, translational kinetic energy, impact duration, mass, and mechanical stiffness. Structures were mounted onto the front of a radio-controlled (RC) car and driven on a linear test track into a rigid wall. Accelerations measured during the collisions were numerically integrated to determine velocities over the impact and collapse/compression of the structures. Flight tests conducted with small RC quadcopters demonstrated that the collapsible structures could successfully be used to mitigate collisions, enough to enable the quadcopters to continue flying after a direct impact and to land indoors or on outdoor terrain with varying slopes and surfaces. Based on trade-off comparisons between the evaluative metrics of the cases studied, conical Pako Pako structures with uniform stiffness are shown to be the most effective for collision resilience and landing.

A ferroelectric capacitor with an asymmetric double-layered ferroelectric structure comprising a liquid-delivery MOCVD Pb(Zr, Ti)O3 layer and a sputter-deposited La-doped Pb(Zr, Ti)O3 for highly reliable FeRAM

We have developed a double-layered ferroelectric capacitor comprising a liquid-delivery metal–organic chemical vapor deposition-based Pb(Zr, Ti)O3 (PZT) lower layer and a sputter-deposited La-doped Pb(Zr, Ti)O3 (PLZT) upper layer. This structure is designed to achieve a large polarization in the stacked-type capacitor of FeRAM. Ferroelectric capacitors with noble metal electrodes, which are patterned by sputter-etching due to the difficulty of standard chemical reactive etching typically exhibit sloped sidewalls. Consequently, their polarization values, determined by the actual capacitor area, depend on their geometric shape. Our developed capacitor exhibits a 35% increase in polarization compared to an all-sputter-deposited PLZT capacitor. This improvement is due to the reduced total thickness of the developed capacitor achieved by simplifying the bottom electrode structure, which results in steeper capacitor sidewalls. Furthermore, our developed capacitor demonstrates excellent retention margin even after 3000 h of baking at 150 °C, and with a potential endurance of 1014 cycles as predicted by voltage acceleration measurements.

The Influence of Temperature Disturbance on Space Inertial Sensors.

The TianQin program is an independently proposed space-borne detection initiative from China. The inertial sensor, as a crucial component, is susceptible to disturbances from temperature fluctuations, the impact of which on acceleration measurements remains elusive. Therefore, a comprehensive analysis on the influence of temperature disturbance is necessary to avoid errors in acceleration measurement. In this study, we proposed a complete scheme for calculating the level of acceleration noise. Based on the traditional temperature control scheme of using a heat pipe, we developed a systematic heat transfer simulation model to obtain the temperature signals. These signals can then be converted into the frequency domain and used to calculate the acceleration noise level within the target bandwidth. Our results indicate that, with a temperature control of 0.13 K/Hz1/2@1 mHz, the largest contributions to acceleration noise come from the outgassing effect, radiometer effect, and radiative pressure effect, in descending order. The total noise peak is 3.6×10-12 m/(s2⋅Hz1/2) at 1 mHz, which is more than three orders of magnitude higher than the TianQin target of 10-15 m/(s2⋅Hz1/2). This study provides new avenues for evaluating measurement errors and solutions for the TianQin program.

Reduction of Multipath Effect in GNSS Positioning by Applying Pseudorange Acceleration as Weight.

A novel approach is proposed to mitigate the multipath effect that is considered a major source of error in global navigation satellite system (GNSS) positioning in urban areas. We utilize code pseudorange acceleration measurements as a weight in a least squares estimation process. If GNSS signals are reflected off a surrounding surface, they cause large variations in the recorded pseudorange measurement. Accelerations computed at each epoch with three consecutive pseudoranges exhibit significant fluctuations in a multipath signal. As a result, positioning accuracy improved by 75% horizontally and 79% vertically compared to not applying any weight. Even when multipath errors exist, the range acceleration (RA) value is sometimes low at many epochs. When a threshold value for the signal-to-noise ratio was additionally applied besides RA, the positioning accuracy at two test sites (including a deep urban environment) improved by more than 80% in both horizontal and vertical directions.

Accelerometer-assisted computer vision data fusion framework for structural dynamic displacement reconstruction

Accurate displacement measurement provides crucial information for evaluating the structural health condition. It is important to note that both direct and indirect displacement measurement methods have their own limitations, which can be remedied by leveraging each other’s strengths. In this study, a novel accelerometer-assisted computer vision data fusion framework is developed for accurately reconstructing structural dynamic displacement. The framework does not require a specific mathematical model or prior knowledge about the data’s characteristics, allowing it to be applied more broadly across different applications without the constraints of model assumptions. The core of this framework is to integrate successive variational mode decomposition (SVMD) and Bayesian optimization approaches to adaptively determine the weight factors of the fusion components. Importantly, an enhanced optical flow approach is presented for converting pixel movement to structural displacement from natural targets. This approach can effectively reduce the selection of mis-matched points within the ROI (Region of Interest), thereby reducing drift errors. The developed framework is verified via shaking table tests of a reinforced concrete frame structure under seismic excitation. Results indicate that the developed framework excels in accurately estimating structural dynamic displacement. Compared to single-vision displacement identification results, the proposed framework demonstrates lower peak error (< 1.65 mm) and normalized root mean square error (< 0.30). Meanwhile, the reconstructed displacement, by introducing dynamic displacement component from acceleration measurement, presents a wider frequency range than the vision-based displacement.

Gross movement counting of fetuses conceived with assisted reproductive technology using a fetal movement acceleration measurement recorder

To investigate whether assisted reproductive technology (ART) affects gross fetal movement. A prospective cohort study. 65 women who conceived with ART (ART group) and 211 women (control group) without ART recorded fetal movement with the fetal movement acceleration measurement recorder at night weekly after 28 weeks. The number ratio of 10 s epochs with fetal movement to all epochs was calculated as the fetal movement parameter. When no fetal movement was observed for more than 5 min, it was defined as a no fetal movement period, and the average number per hour, the average duration, and the longest duration of the no fetal movement periods were calculated as the no fetal movement parameters. Gestational weeks were classified into 28–33 and 34–39 weeks, and the fetal movement parameter and the no fetal movement parameters were compared using the Student’s t-test. The fetal movement parameters at 28–33 weeks were 17.43% (ART) and 16.58% (control) (p = 0.219), and those at 34–39 weeks were 11.72% (ART) and 11.96% (control) (p = 0.590). In the same way, for the no fetal movement parameters, the average numbers were 1.58 and 1.63 per hour (p = 0.357), and 2.36 and 2.30 per hour (p = 0.503). The average durations were 8.30 and 8.46 min (p = 0.712), and 9.20 and 9.51 min (p = 0.188). The longest durations were 16.26 and 17.02 min (p = 0.295), and 22.34 and 22.87 min (p = 0.534). ART does not affect gross fetal movement count.

Dynamic strain field estimation of fixed offshore support structures using limited acceleration measurements

The strain history affecting the fatigue life of fixed offshore support structures is one of the most important topics in structural monitoring. However, some critical fatigue locations are located below the seabed, and the installation of strain gauges at these locations entails significant maintenance costs. In contrast, acceleration which reflects the vibration characteristics of the structure is an easily accessible and more stable physical parameter. Therefore, this study presents a strain estimation scheme that uses limited acceleration measurements to estimate the dynamic strain field of the fixed offshore support structures. An adaptive displacement reconstruction method is used to obtain the displacements at the master degrees of freedom, then the global displacements are obtained by the evolutionary orthogonal response expansion method, and finally, these displacements are implemented into the numerical software by redefining the boundary conditions to obtain the dynamic strain field. The advantage of the proposed method over the traditional strain-solving forward problem is that it relies solely on measured acceleration and structural geometry information, without requiring displacement, strain, or modal information. The correctness of the proposed method is verified by a numerical jacket platform model with multi-harmonic and non-stationary random excitations. Furthermore, physical experiments under eccentric rotation and hammering excitations are performed to assess the applicability of the proposed method on a wind turbine model equipped with laser displacement and fibre bragg grating sensors as reference measurements. The results show that the proposed method can accurately predict the dynamic strains of jacket platform and wind turbine support structures, while the appropriate agreement between the estimated strains and the numerical results, and the optical measured response is observed, with maximum estimation errors of 1.80% and 4.63%, respectively. Summarily, the application of the approach enables a new type of strain monitoring applicable to fixed offshore support structures.

Experimental analysis of wheel and bogie frame transfer functions for on-board measurements of rail roughness

Acceleration measurements on in-service rail vehicles give many valuable insights into track condition. These measurements are favourable in terms of measurement frequency, no need for additional track possession for measurements, operator safety, etc. The collected acceleration data however needs to be further processed to extract more detailed information on rail surface defects. To derive rail roughness from bogie frame acceleration, a complex signal processing approach is required, as well as determining the dynamic parameters of the track, vehicle, and operational conditions. In this paper, a method to evaluate the influence of resilient wheel and bogie frame on the acceleration data received from bogie frame-mounted accelerometers is described. The method is based on a standstill measurement of frequency response functions on wheel and bogie frame positions using an impact hammer and accelerometers. Following the preliminary results of bogie acceleration measurements, in-situ wheel receptance measurements were carried out on the same tramway vehicle in a standstill position, to determine the transfer function between the wheel-rail contact point and the position of the accelerometer mounted on the wheel frame. After the experimental study, a discussion of their potential application in the method for deriving rail roughness from vibration data is presented.

Resonant frequencies of multi-layer building constructions: Estimation by measurement of acceleration amplitudes

The Austrian building regulation requirements for impact sound insulation are based on the weighted standardized impact sound pressure level as single-number specification. In recent years, it has become apparent that not only the single-number specification, but the extended frequency range and frequency characteristics of impact sound insulation of constructions can have noticeable influence on the perceived acoustic performance of a construction. Therefore, the Austrian Classification Standard ÖNORM B 8115-5: 2021-04 includes extended requirements on impact sound insulation. It provides two ways for verification of the sound insulation classes A to C. One way is the verification via the resonance frequency of multi-layer constructions. However, there exist as yet no standardized measurement methods for the estimation of the resonance frequency of multi-layer building constructions. In response, in course of this study a new measurement method for the estimation of the resonance frequencies of multi-layer constructions was developed. For this development acceleration measurements were carried out on both surfaces of particularly double-layer building constructions, that were excited with a rubber hammer. From these measurement results, in conjunction with an analytical model, it was possible to derive a measurement method for estimating the resonant frequency via the frequency characteristics of the acceleration amplitudes.

LSTM Gate Disclosure as an Embedded AI Methodology for Wearable Fall-Detection Sensors

In this paper, the concept of symmetry is used to design the efficient inference of a fall-detection algorithm for elderly people on embedded processors—that is, there is a symmetric relation between the model’s structure and the memory footprint on the embedded processor. Artificial intelligence (AI) and, more particularly, Long Short-Term Memory (LSTM) neural networks are commonly used in the detection of falls in the elderly population based on acceleration measures. Nevertheless, embedded systems that may be utilized on wearable or wireless sensor networks have a hurdle due to the customarily massive dimensions of those networks. Because of this, the algorithms’ most popular implementation relies on edge or cloud computing, which raises privacy concerns and presents challenges since a lot of data need to be sent via a communication channel. The current work proposes a memory occupancy model for LSTM-type networks to pave the way to more efficient embedded implementations. Also, it offers a sensitivity analysis of the network hyper-parameters through a grid search procedure to refine the LSTM topology network under scrutiny. Lastly, it proposes a new methodology that acts over the quantization granularity for the embedded AI implementation on wearable devices. The extensive simulation results demonstrate the effectiveness and feasibility of the proposed methodology. For the embedded implementation of the LSTM for the fall-detection problem on a wearable platform, one can see that an STM8L low-power processor could support a 40-hidden-cell LSTM network with an accuracy of 96.52%.

The Imprint of Dark Matter on the Galactic Acceleration Field

Measurements of the accelerations of stars enabled by time-series extreme-precision spectroscopic observations, pulsar timing, and eclipsing binary stars in the solar neighborhood offer insights into the mass distribution of the Milky Way that do not rely on traditional equilibrium modeling. Given the measured accelerations, we can determine a total mass density and infer the amount of dark matter (DM) by accounting for the mass in stars, gas, and dust. Leveraging FIRE-2 simulations of Milky Way–mass galaxies we compare vertical acceleration profiles between cold DM (CDM) and self-interacting DM (SIDM) with a constant cross section of 1 cm2 g−1 across three halos with diverse assembly histories. Notably, significant asymmetries in vertical acceleration profiles near the midplane at fixed radii are observed in both CDM and SIDM, particularly in halos recently affected by mergers with satellites of Sagittarius/SMC-like masses or greater. These asymmetries offer a unique window into exploring the merger history of a galaxy. We show that SIDM halos manifest a more oblate shape and consistently exhibit higher local stellar and DM densities and steeper vertical acceleration gradients, up to 10%–30% steeper near the solar neighborhood. However, similar magnitude changes can arise from azimuthal variations in the baryonic components at a fixed radius and external influences like mergers, making it difficult to distinguish between CDM and SIDM using acceleration measurements in a single galaxy.