Acceleration Values Research Articles

Early player transition in elite youth and first team soccer: The predictive role of sprint distance and high-intensity acceleration and deceleration attributes

Physical performance is an important determinant of elite youth soccer player development and can influence successful transition through the professional phase of the talent development pathway. In response to previous research highlighting key stakeholders’ perceptions that successful transitions within the club pathway are influenced by sprinting capacity and explosive power; this study objectively quantified the predictive value of sprint distance and high intensity acceleration and deceleration efforts on the early transition of elite, professional youth soccer players from U18 to U21, and U21 to first team squads of a Scottish Premier League club. Early transition was defined as a player progressing to the next age group (i.e., U18 to U21) prior to reaching the chronological age limits of his current squad. Retrospective physical performance data of thirty-seven players from training and competitive matches across two seasons were analysed. Results suggest that early transition is less likely for players progressing from the U21 to the first team relative to players progressing from U18 to U21. Relative sprint distance resulted in a 52% probability of early transition (OR = 0.52) with relative aggregated high intensity acceleration and deceleration efforts reflecting an increased probability of early transition (OR = 1.70) for elite youth soccer players within the club. This novel study provides a unique insight to the complexities and context-specific nature of youth soccer player development and transition. This paper challenges the subjective perceptions of key stakeholders using objective physical data of youth players who have transitioned to advanced squads.

Vehicle active suspension control considering parameter uncertainty and velocity variation

Due to the uncertainty in vehicle model parameters, the control performance of active suspensions often deteriorates, especially under extreme conditions such as high velocities and full loads. To address this challenge, this paper proposes a novel robust finite frequency H ∞ output feedback control strategy based on linear parameter varying (LPV) systems. First, we establish a new LPV model for the half-car active suspension control system, taking into account the uncertainties associated with vehicle velocity and sprung mass. Next, a robust finite frequency H ∞ output feedback controller is designed using a gain scheduling approach, formulated through a set of linear matrix inequalities (LMIs). Finally, simulation results demonstrate that the proposed velocity-dependent robust control strategy significantly reduces the root mean square (RMS) values of vertical acceleration by approximately 21% to 31% under various conditions of sprung mass and vehicle speed compared to traditional control methods.

Detecting flying objects in synthetic aperture radar images using Moving Target Indicator methods

AbstractThe growing proliferation of synthetic aperture radar (SAR) sensors brings the tantalising prospect of extending their utility into ‘novel’ applications. One potential extension is the detection of fast moving and accelerating flying objects in SAR imagery. However, since SAR image formation typically assumes the scene to be static over the coherent processing interval, moving objects give rise to blurred point spread functions, significant range migration and even potential aliasing of target signatures. The result is reduced target to clutter ratio (TCR) and poor detection performance. Successful detection of airborne targets thus requires compensation for potentially large target acceleration and velocity values observed over the comparatively long dwell times typical of practical SAR collection paradigms. This paper considers this problem and presents two main ideas to achieve this goal: a carefully constructed Moving Target Indicator (MTI) detection method implemented using real‐world Ingara SAR data, and a theoretical ground clutter suppression method. The MTI detection method combines several well‐known techniques for the flying target detection problem: interferometric processing, clutter suppression, and autofocus, and provides an extended acceleration phase compensation technique for highly accelerating targets such as planes. This proposed processing pipeline has been applied to experimental data of a plane during take off (a challenging Doppler unambiguous moving target), with the goal of continued detecting and tracking of this target. A generalised SAR signal model is presented that parameterises a flying moving target signature in terms of range and azimuthal target velocities and accelerations. Data driven approaches for estimating these motion parameters are examined and applied to experimental data acquired with the Ingara SAR sensor. The detection method was found to improve TCR by around 6 dB, along with superior detection and tracking performance. Following this, a theoretical study into suppressing ground clutter via multi‐channel cross‐track interferometry is investigated. Three separate ground clutter suppression methods, coherent subtraction, conventional beamforming, and minimum variance distortionless response (MVDR) beamformer, are presented then analysed using stochastic simulations. The MVDR adaptive beamformer method was found to provide the best performance for the scenario simulated.

Establishing reliable acceleration-speed profiles: Minimum data requirements in rugby union matches

ABSTRACT The aim of this study was to determine the minimum playing time in matches required to produce reliable acceleration – speed (AS) profiles from global navigation satellite system (GNSS) data. The playing time of 25 professional rugby union players was recorded using GNSS technology and segmented into four sections from 40, 80, 120 and 160 minutes of play. For each interval, the impact of integrating new match data on the AS profile was assessed, aiming to identify the saturation point where additional data did not induce significant changes in the profile outputs. A repeated measures ANOVA and Bonferroni post-hoc tests were applied to examine the variations of AS profile between time intervals. This led to identify the saturation point for assessing “robust” values of theoretical maximum acceleration (A0) and maximum speed (S0). A substantial lack of significant effect was observed for A0 (p = 1.00) and S0 (p = 0.99) in the section of 160 minutes, with an intra-subject variability of 1.50 and 1.20% for A0 and S0, respectively. Determining AS profiles for rugby players is essential for monitoring performance in training and match contexts. Our findings indicate that an equivalent of two full rugby union matches is required to generate a reliable AS profile.

Research on ride control strategy of electromagnetic suspension based on sliding mode algorithm

This study proposes a main inner loop control technique to address the dynamic response of the electromagnetic suspension during vehicle driving. The genetic algorithm is employed to optimize the control parameters of the linear quadratic adjustment controller in the control main loop, with the aim of achieving the desired control force. In the control inner loop, a closed-loop sliding mode controller is designed based on the exponential approximation law to regulate the current. The Lyapunov function was utilized to assess the stability of the controller in terms of its theoretical feasibility. The simulation results of Matlab/Simulink show that under the given working conditions, compared with the passive suspension, sliding mode control and fuzzy sliding mode control for references, the root mean square value and peak value of the vertical acceleration of the body and the dynamic load of the tire with the improved sliding mode control are significantly reduced, the root mean square value of the dynamic deflection of the suspension was not improved. However, on the whole, the ride comfort of the vehicle has been improved.

Assessment of Building Nondeterministic Dynamic Structural Behavior considering the Effect of Geometric Nonlinearity and Aerodynamic Damping

The objective of this research is to evaluate the dynamic structural response of tall buildings subjected to wind loads, taking into account the influence of geometric nonlinearity and aerodynamic damping. The project focuses on a steel-concrete composite structure with 48 floors and a height of 172.8 m, examining its response to wind non-deterministic dynamic actions. The building finite element model was developed based on the Finite Element Method (FEM), using the ANSYS computational program, and considering the soil-structure interaction effect, with the objective of obtaining a realistic representation of the dynamic behavior. The building dynamic response was obtained based on the displacement and acceleration values, determined with the consideration of a wind velocity range between 5 m/s (18 km/h) and 45 m/s (162 km/h). The findings of this study indicate that when the effect of geometric nonlinearity was incorporated into the analysis, the dynamic response of the investigated building exhibited notable discrepancies. The maximum differences observed in the horizontal translational displacements and accelerations were 30% and 45%, respectively. In contrast, the inclusion of aerodynamic damping had a negligible impact on the structural dynamic response, with maximum differences of 5% for displacements and 10% for accelerations.

A fractional adaptive type-2 fuzzy structural control system: Theoretical/experimental study

A new modified sliding mode control (SMC) method based on type-2 fuzzy neural networks (T2FNNs) is introduced for the active mass damper (AMD) systems. An adaptive T2FNN is used in the switching part, and another adaptive T2FNN is used to estimate the uncertainty of the AMD system. T2FNNs are adopted to predict the system’s uncertainties and establish a dynamic model of the AMD system, independent of the mathematical model. The chattering phenomenon is also taken into account and analyzed. The stability is studied by using the Lyapunov approach to derive training rules for both T2FNNs in dynamic modeling and switching part. Numerical simulation and experimental verifications confirm the feasibility and effectiveness of the designed T2FNN based SMC. The results reveal that the designed controller outperforms the conventional controllers in reducing the vibration peak and reducing the root mean square (RMS) value of structural displacement and acceleration. It also exhibits good robustness against external disturbances and structural dynamic perturbations. The suggested algorithm combines the advantages of adaptive control and fuzzy logic, addressing the issue of chattering in control and overcoming the lack of self-learning capability in conventional SMCs.

Investigation of Earthquake Disaster Risk Using ArcGis Satellite Imagery Study Case in North Tapanuli Regency

Abstract Earthquakes are one of the natural phenomena that occur surprisingly without any signs or symptoms that can be felt by humans, so that generally earthquakes cause tremendous panic. Tectonic earthquakes from faults generate a Peak Ground Acceleration (PGA) value, which helps assess their risk impact. North Tapanuli Regency is one of the districts in Indonesia that is passed by two faults, namely Renun and Toru. To determine the risk of earthquake disasters in the area, calculations are carried out using spatial methods to obtain values of PGA, Mmax, and Tmax values. From the processing results, it is known that the maximum magnitude of the Toru segment is 7.37 M and the Renun segment is 7.69 M, and the Toru segment has a maximum earthquake return period in the Toru segment of 429 years and the renun segment has a return period of 1013 years. Also, a disaster mitigation map is obtained that is formed using the PGA value as a parameter, with an explanation that areas that have a higher PGA value (colored red) have a greater risk of being affected by an earthquake.

Assessment of seismic liquefaction hazard and ground response in subduction zone: A 1D non-linear effective stress approach

Abstract The Makran Subduction Zone (MSZ) represents a convergent plate boundary where the Arabian Plate is subducting beneath the Eurasian Plate. This study assessed liquefaction susceptibility and ground response in Gwadar region, located on the eastern side of MSZ. A comprehensive dataset of seismic records, compatible with Pakistan design code BCP: 2021 rock spectrum, was used as input motions at bedrock. A series of one-dimensional (ID) non-linear effective stress analyses (NL-ESA) was conducted using DEEPSOIL v7 numerical tool. The findings revealed that pore water pressure ratio (ru) exceeded the threshold value for liquefaction onset (ru > 0.8) at various depths within the site profiles. A significant de-amplification of peak ground acceleration values was observed at liquefiable depths in soft soils. The liquefied stratum exhibited a non-linear response, with high shear strain values manifesting plastic deformations. A comparison of computed design spectra with code spectra revealed significant discrepancies. It is demonstrated that BCP: 2021 underestimated site amplification for site class D profiles in the 0.1 to 0.8 s period range, while overestimating it for site class E profiles across the entire period range up to 1.6 s. The findings will benefit infrastructure development in the region, particularly within the China-Pakistan Economic Corridor.

Experimental Comparison of the Performance of Shear Frame with TLD and TLCD Under Harmonic Ground Motion

Today, various systems are used to reduce vibrations in civil engineering structures. Among these systems, tuned liquid dampers are the preferred passive systems due to their ability to be designed in different geometries, their low cost, their ease of installation, and their low maintenance costs. This study examines the effectiveness of tuned liquid dampers (TLD) and tuned liquid column dampers (TLCD) under identical geometric conditions and harmonic ground motion to assess which is more efficient in controlling the behavior of a three-storey steel shear frame model equipped with these systems. A small-scale, three-storey shear frame model placed on a uniaxial shaking table was subjected to harmonic motion with a 5 mm amplitude, 1.4 Hz frequency, and 10 cycles. The chosen frequency aligns with the resonance frequency of the undamped building model’s first mode. Both TLD and TLCD tanks, positioned atop the structure, share a geometry of 30 cm in length and 10 cm in width, with variable liquid heights of 5, 10, 15, and 20 cm. Mounting TLD and TLCD models with four different liquid heights on the undamped model resulted in nine distinct setups. In this designed scenario, the TLDs and TLCDs on the undamped shear frame were compared according to liquid heights at rest. To identify the best-performing system based on liquid height, response displacement–frequency graphs were generated for all models within a frequency range of 0.5–2.5 Hz, and damping ratios were calculated using the half-power bandwidth method. Additionally, harmonic ground motion experiments at the resonance frequency compared both acceleration and displacement values over time for damped and undamped models. Peak acceleration and displacement values on each floor were also analyzed. The results highlight which system proves more effective based on damping ratio, acceleration, and displacement values under equivalent conditions.

Prototype of small-scale test machine for vibration measurement on bearings

Repetitive movements of shaft in bearings over time intervals generate vibrations. The aim of this research is to build the prototype of small scale of machine to measure the vibration values of bearing due to spinning shaft using an accelerometer and Arduino sensor device. The method used is to build a device of miniature rotating machines which was used to simulate machine vibrations. The ADXL345 accelerometer measured the magnitudes of vibration that occurs on the rotating shaft. Arduino Uno analyzed data from ADXL345. The amplitude, speed, acceleration and frequency values were measured according to rotation values. It was found the largest amplitude, speed, acceleration and frequency values were obtained at the radial point Y1 position.

Self-Sensing Approach for Semi-Active Control of Variable Damping Electromagnetic Suspension System

This paper combines the Kalman filter observer with self-sensing technology and integrates it into the electromagnetic damper (EMD), estimating the displacement and velocity of the EMD based on the three-phase voltage generated by the permanent magnet synchronous motor (PMSM). The self-sensing performance of the EMD is verified through theoretical analysis and experimental results. A vehicle suspension vibration control system composed of one-quarter vehicle electromagnetic suspension (EMS), a acceleration damping driven control (ADDC) algorithm, and a vibration excitation platform is established to test the vibration control performance of the self-sensing EMS. The experimental results show that under random road excitation, compared to passive suspension, the self-sensing-based ADDC reduced the vehicle vertical acceleration of the vehicle suspension, with a 28.92% decrease in the root mean square (RMS) value of the vehicle vertical acceleration. This verifies the effectiveness of the self-sensing capability of the EMS system. Incorporating self-sensing technology into the EMS system improves the vibration reduction performance of the suspension.

Utilizing smartphone proximity sensor to analyse accelerated motion of object in an inclined plane and determine the acceleration and kinetic friction coefficient

Abstract In this work, we launched smartphones with a moving object to analyse the motion on an inclined plane. The data of time versus distance was acquired by utilizing a smartphone proximity sensor to record time intervals between detection objects whose distance had been set beforehand. The plot of time versus distance was used to analyze the characteristics of accelerated motion. Meanwhile, time squared versus distance was used to determine acceleration. The inclination angle was varied to observe the effect on the motion characteristic and acceleration value. Furthermore, kinetic friction coefficient existing along the object’s motion was also calculated.

Inertial mass modeling and compensation for an energy-harvesting vehicle suspension system with limited-DOF parallel mechanisms actuator

An energy-harvesting suspension can improve the energy efficiency of vehicle. By introducing a lower-mobility parallel mechanism as motion transfer in the energy-harvesting suspension, the stiffness of the system is significantly improved. However, the overlage equivalent of inertial mass make the system is difficult to control and imped the development of this kind of suspension. To solve the problem, an equivalent linearization model to calculate the nonlinear inertial mass of low-DOF (Degree Of Freedom) parallel mechanism actuator is studied firstly. Furthermore, a 2-DOF 1/4 suspension system dynamic model that includes inertial mass is proposed to analyze the vehicle acceleration, dynamic tire load, and dynamic stroke. On this basis, the linear-quadratic Gaussian (LQG) controller is adopted to compensate the inertial mass of the suspension to improve the system performance. Results show that the proposed model accurately reflects the characteristics of the suspension inertial mass, the root-mean-square (RMS) value of the vehicle body acceleration and suspension dynamic stroke through compensation controller is reduced by 33.4% and 30.89%, respectively. Moreover, the RMS of the dynamic tire load is reduced by 3.06%, and the system stability is improved significantly.

Unsupervised classification of Blanding's turtle (Emydoidea blandingii) behavioural states from multi-sensor biologger data.

Classifying animal behaviors in their natural environments is both challenging and ecologically important, but the use of biologgers with multiple sensors has significantly advanced this research beyond the capabilities of traditional methods alone. Here, we show how biologgers containing an integrated tri-axial accelerometer, GPS logger and immersion sensor were used to infer behavioural states of a cryptic, freshwater turtle, the Blanding's turtle (Emydoidea blandingii). Biologgers were attached to three males and five females that reside in two undisturbed coastal marshes in northeastern Georgian Bay (Ontario, Canada) between May and July 2023. Raw acceleration values were separated into static and dynamic acceleration and subsequently used to calculate overall dynamic body acceleration (ODBA) and pitch. The unsupervised Hidden Markov Model (HMM) successfully differentiated five behavioural states as follows: active in water, resting in water, active out of water, resting in water, and nesting. Overall accuracy of the classification was 93.8%, and except for nesting (79%), all other behaviours were above 92%. There were significant differences in daily activity budgets between male and female turtles, with females spending a greater proportion of time active out of water, and inactive out of the water, while males spent a greater proportion of time active in water. These differences were likely a result of large seasonal life-history requirements such as nesting and mate finding. Accurate classification of behavioural states is important for researchers to understand fine-scale activities carried out during the active season and how environmental variables may influence the behaviours of turtles in their natural habitats.

A Five-Axis Toolpath Corner-Smoothing Method Based on the Space of Master–Slave Movement

The smoothing of linear toolpaths plays is critical in improving machining quality and efficiency in five-axis CNC machining. Existing corner-smoothing methods often overlook the impact of spline curvature fluctuations, which may lead to acceleration variations, hindering surface quality improvements. The paper presents a five-axis toolpath corner-smoothing method based on the space of master–slave movement (SMM), aiming to minimize curvature fluctuations in five-axis machining and improve surface quality. The concept of movement space in master–slave cooperative motion is introduced, where the tool tip position and tool orientation are decoupled into a main motion trajectory and two master–slave movement space trajectories. By deriving the curvature monotony conditions of a dual Bézier spline, a G2-continuous tool tip corner-smoothing curve with minimal curvature fluctuations is constructed in real-time. Subsequently, using the SMM and the asymmetric dual Bézier spline, a high-order continuous synchronization relationship between the tool tip position and tool orientation is established. Simulation tests and machining experiments show that with our smoothing algorithm, maximum acceleration values for each axis were reduced by 21.05%, while jerk was lowered by 22.31%. These results indicate that trajectory smoothing significantly reduces mechanical vibrations and improves surface quality.

Вібрація в будинках, вимоги до допустимих рівнів та критерії оцінки

Objective. The purpose of the study is to determine the current requirements for vibration regulation in buildings. Object and methods of the study. Standards: ISO 2631-1:1997; ISO 2631-2: 2003; DSTU ISO 2631-1:2004; DSTU ISO 2631-2: 2004; BS 6472-1:2008; ONORM S 9012:2010 (Austria); DIN 4150-2:1999 (Germany); UNI 9614:1990 (Italy); Japan: Vibration Control Law; SBR Richtli - Deel B 2002 (Netherlands); NS 8176:2005 (Norway); Real Decreto 1307/2007 (Spain); SS 4604861:1992 (Sweden); FRA (2005), FTA, 2006 (USA). Research results and discussion. The main parameters of vibration, thresholds of sensitivity and comfort, vibration evaluation criteria (VDV, eVDV), directions of action of general vibration, frequency weighting curves (Wb, Wd, Wm), the probability of complaints at different values of vibration acceleration, desirable and maximum weighted average values of vibration acceleration for continuous and impulsive vibration in buildings were analyzed. The current DSTUs on vibration in buildings in Ukraine are analyzed. It was found that these standards are outdated (old coordinate systems and old values of the coefficients of frequency weighting curves are used). It was found that there are no standards for permissible levels or values of vibration in buildings for humans in Ukraine. Conclusions. As a result of the analysis of the considered standards, it was found that the main parameters of vibration are: vibration displacement, vibration velocity; vibration acceleration. Vibration acceleration is most often used. Vibration perception thresholds are not consistent with existing standards, which use frequency weighting factors that do not sufficiently take into account human sensitivity. In different countries, limit value criteria are set above the perception thresholds. Some of them are derived from the threshold irritation level. Vibration criteria are based on maximum and average values. The former are more related to sleep disturbance, the latter are more related to irritation. Keywords. Vibration, standards, vibration criteria, vibration perception thresholds.

Does the External Load Have an Impact on Winning Matches in Football?

The present study was conducted to examine the impact of external load on winning matches in football. The study group comprised players of the football team in the Spor Toto 1 st League. A total of 13 matches, including 6 won matches and 7 lost matches, were used in the analysis. The data on matches were taken from the 2022-2023 season of the Spor Toto 1st League. The following external load parameters were used in the analysis: total running distance (m), total high-speed running (HSR) distance, total sprint distance (m), acceleration distance (m), deceleration distance (m), ACD load, and maximum sprint reached (km/h). Data were collected with the wearable technology tracking system on football players during matches via GPS. The independent t-test was used in the program (SPSS 26.0) when analyzing normally distributed research data. The analysis of research data found a statistically significant difference in the total distance covered, total HSR distance, total sprint distance, and acceleration values among the external load results for the won and lost matches (p 0.05) but did not find a statistically significant difference in the deceleration, ACD load, and sprint speed values (p>0.05). Consequently, it can be concluded that differences in many values that are considered necessary for success in the football field have an effect on winning matches in football. For values with no statistical difference, it may be recommended to conduct studies in a higher league, with more matches and more players. Keywords: football, external load, gps

Advancements in Bamboo-Based Cushioning Material Manufacturing

The study focuses on producing cushioning packaging material from bamboo fibers. The effects of varying the surface treatment duration and the proportions of foaming agents, adhesives, plasticizers, cross-linking agents, and other components were analyzed in terms of foam density, foaming rate, elasticity, and bubble size. The optimal reagents and the ideal ratios for the different components were identified. The parameters for the foaming process were determined based on a high-efficiency, eco-friendly foaming mechanism. Impact testing was conducted to obtain curves for maximum acceleration versus static stress, dynamic stress versus strain, and dynamic buffering factor versus stress. The study examined the dynamic buffering performance as a function of drop height and compared it to other cushioning materials. The findings indicate that at a height of 450 mm, the bamboo pulp product exhibited a lower peak acceleration value than EPE and EPS in the stress range of 2.8-5.4 kPa, indicating superior cushioning performance under these conditions.

Duration Models for Subduction Earthquakes

ABSTRACT An empirical model for the significant duration of acceleration for subduction zone earthquakes is developed based on the normalized Arias intensity. The data set is a subset from the Next Generation Attenuation-Subduction database (Bozorgnia and Stewart, 2020). The functional form of the duration model uses an additive model for the source, path, and site terms with three lognormally distributed random effects for the source, path, and site. The remaining aleatory variability is modeled by a power-normal distribution. There are two parts of the duration model: a model for the D5–75 duration and a model for the D5–X/D5–75 ratio, which can be combined with the D5–75 model to estimate the DY–X for any interval. The D5–75 model includes regionalized coefficients for Japan, New Zealand, South America, and Taiwan. The large-magnitude (M >7) scaling of the D5–75 model is much weaker than the recent duration model by Bahrampouri et al. (2021). The residuals of the D5–75 model are negatively correlated with the lnPGA residuals with a correlation coefficient of −0.50 such that above-average peak ground acceleration values are associated with below-average duration values.