Track Position Research Articles

Shower separation in five dimensions for highly granular calorimeters using machine learning

To achieve state-of-the-art jet energy resolution for Particle Flow, sophisticated energy clustering algorithms must be developed that can fully exploit available information to separate energy deposits from charged and neutral particles. Three published neural network-based shower separation models were applied to simulation and experimental data to measure the performance of the highly granular CALICE Analogue Hadronic Calorimeter (AHCAL) technological prototype in distinguishing the energy deposited by a single charged and single neutral hadron for Particle Flow. The performance of models trained using only standard spatial, energy and charged track position information from an event was compared to models trained using timing information available from AHCAL, which is expected to improve sensitivity to shower development and, therefore, aid in clustering. Both simulation and experimental data were used to train and test the models and their performances were compared. The best-performing neural network achieved significantly superior event reconstruction when timing information was utilised in training for the case where the charged hadron had more energy than the neutral one, motivating temporally sensitive calorimeters. All models under test were observed to tend to allocate energy deposited by the more energetic of the two showers to the less energetic one. Similar shower reconstruction performance was observed for a model trained on simulation and applied to data and a model trained and applied to data.

Real-Time Table Tennis Scoring and Player Position Tracking System Using Computer Vision

This study focuses on developing a system that uses state-of-the-art computer vision techniques to improve the accuracy and efficiency of table tennis tracking. The table tennis ball's trajectory and movement are tracked automatically by the system using a mobile camera array, allowing for real-time score updates without the need for human participation. This method guarantees precise and seamless scoring, freeing players from worrying about maintaining score and allowing them to concentrate fully on the game. The system uses player pose estimation technologies in addition to real-time scoring to track and record player positions and motions during the match. The system may provide a thorough study of player motions, including tracking posture and finding important motion patterns, by gathering and analyzing skeletal data.

Enhanced deep potential model for fast and accurate molecular dynamics: application to the hydrated electron.

In molecular simulations, neural network force fields aim at achieving ab initio accuracy with reduced computational cost. This work introduces enhancements to the Deep Potential network architecture, integrating a message-passing framework and a new lightweight implementation with various improvements. Our model achieves accuracy on par with leading machine learning force fields and offers significant speed advantages, making it well-suited for large-scale, accuracy-sensitive systems. We also introduce a new iterative model for Wannier center prediction, allowing us to keep track of electron positions in simulations of general insulating systems. We apply our model to study the solvated electron in bulk water, an ostensibly simple system that is actually quite challenging to represent with neural networks. Our trained model is not only accurate, but can also transfer to larger systems. Our simulation confirms the cavity model, where the electron's localized state is observed to be stable. Through an extensive run, we accurately determine various structural and dynamical properties of the solvated electron.

Vertical Track–Bridge Interaction in Railway Bridges with Ballast Superstructure: Experimental Analysis of Dynamic Stiffness and Damping Behavior

Realistic vibration predictions of railway bridges during high-speed train crossings require reliable dynamic input parameters for the applied calculation model. In particular, the dynamic stiffness and damping properties of the ballast superstructure for the mathematical consideration of the vertical track–bridge interaction (TBI) significantly influence the generated calculation results. However, due to a striking scattering of model-related characteristic values available in the literature, adequate and realistic consideration of the dynamic properties of the vertical TBI in vibration predictions is associated with considerable uncertainties. This uncertainness illustrates the need to determine experimental-based and reliable characteristic values. For targeted and isolated research of dynamic characteristics of vertical TBI, a unique large-scale test facility was developed at the Institute of Structural Engineering at TU Wien, which replicates a section of ballast superstructure on a railway bridge on a scale of 1:1 and excited to vertical movements. This paper presents the essential results and findings from the experiments, focusing on determining the ballast superstructure’s dynamic stiffness and damping characteristics, which can subsequently be implemented in practical applications for vibration predictions. As a result of the experiments, model-related dynamic stiffness and damping parameters are provided to describe the vertical TBI. In addition, the experiments are used to identify destabilization processes occurring in the ballast superstructure as a result of vertical vibrations. The investigations include the vertical TBI’s displacement and acceleration behavior and the track’s settlement behavior due to the entire structure’s vertical movements. These investigations allow for assessing the currently valid, internationally, and nationally normatively prescribed permissible accelerations for railway bridges due to train crossings. The conclusion is that short-term excessive vertical accelerations of the ballast superstructure caused by train passage do not destabilize the ballast bed or considerably change the track position.

The development of patient-specific quality assurance (PSQA) for a proton wobbling nozzle using PTSim Monte Carlo code

The aim of this study is to develop a Monte Carlo-based platform for patient-specific quality assurance (PSQA) in the proton wobbling nozzle at Chang Gung Memorial Hospital. To efficiently reduce time usage and enhance simulated precision, this platform required an initial fine-tuning of the Guard volume (GV) and lateral displacement (LD) settings. Different GV sizes combined with LD modes were utilized to estimate depth dose profiles in a water phantom. The simulated central axis depth doses were then analyzed using PTSim and compared to measurement using a PTW MP3 water tank and a Markus ionization chamber type 34045. Treatment parameters for a liver case were extracted from the Eclipse DICOM RT Plan file. Simulated doses were compared to measurements using Zebra and MatriXX systems during PSQA process. Furthermore, a geometrical trigger technique was applied to assess the track positions in patient-specific components. The study found that the mean dose difference between measured and simulated values for the optimized LD/GV was below 1% at all depth positions. With passing rates of 97.4% at the middle SOBP and 90.3% at the proximal SOBP, the gamma analysis demonstrated satisfactory results. For the axial dose profile, SOBP flatness was within 2.5%. From the geometric trigger analysis, more than 95–98% of the dose was delivered through the range compensator, while approximately 2–5% originated from scattered protons from the Multi-Leaf Collimator (MLC) and block's edges. The PTSim simulation's performance in conducting PSQA demonstrated its capability and reliability.

VACUUM SYSTEM FOR COATING PARTS OF ROCKET AND SPACE EQUIPMENT

A vertical type vacuum plant was created for applying coatings using the ion-plasma deposition method to the inner surface of hollow products with a diameter of up to 200 mm and a length of up to 1000 mm. The plant includes: a vacuum chamber with a vacuum system, an evaporator with a magnetic system, a power supply and control system, a cooling system. Radial evaporation cathode of tubular shape with controlled arc is used. Inside the cathode is a magnetic system that controls the movement of cathode spots on its surface. Permanent magnets create arched magnetic fields that hold the position of the discharge track in the tangential direction. The trajectory of the movement of the cathode spots has the form of an ellipse stretched along the cathode. For uniform spraying of the cathode surface, the track moves in two directions: around the circumference of the cathode surface and along its length. A mechanism for moving the magnetic system is mounted on the cover of the vacuum chamber. The product to be coated is mounted inside the vacuum chamber in a vertical position thanks to the removable top cover. The necessary rarefaction of the atmosphere (vacuum) is achieved with the help of two vacuum pumps. Coating materials are traditional Сr and Ni-Cr alloys. A feature of the coating structure is presented: the formation of a combination of solid condensed and soft droplet phases. The droplet phase is a part of the evaporator material with several times lower hardness compared to the nitrided condensed phase. The distribution of the soft phase in a strong coating prevents its brittleness, which is important for thick coatings. The disadvantage of the vacuum-arc deposition process is the heating of the part to a temperature of 380-450 °C. To exclude the softening of the main metal of the combustion chamber and nozzle, it is recommended to use bronze alloys with a recrystallization temperature of at least 500 °C.

TRACKING SYSTEM USING GPS AND SMART CARD AUTHENTIFICATION BASED ON ESP 32 MCU

Logistics distribution is a series of activities that are interconnected in each process. Therefore, an information system is necessary to record, report conditions, and display the current location of items directly. An Android-based application system is vulnerable to spoofing, such as fake GPS. The application is used to falsify the coordinates of digital map locations. This research aims to develop a common tracking system and prevent Fake GPS by employing the System Development Life Cycle method, consisting of several stages, i.e., planning, analysis, design, implementation, testing, and maintenance. In this research, a prototype of the tracker tool and its information system were made. It used an RFID Smart Card for courier identity authentication and a GPS module to track position information on a digital map. RFID and GPS were controlled using the ESP32. Furthermore, the Website served as an information system to read and create a QR Code to identify the goods carried. It received data from the RFID Smart Card and GPS, stored it in the Database, and displayed it online. The test results indicated that the tracker prototype succeeded in sending location data throughout the test and gained an average distance of 6.82 meters, which was different from a commercial GPS device. It had a delay of 268.5 seconds when the location was first read. The tracker prototype had an average power consumption of 1.5 watts, an average battery life of 2 hours, 28 minutes, and 40 seconds, as well as an average battery deficiency of 36.79%. In conclusion, the system test was successful.

Effect of additional herbage areas on grazing dairy cows in commercial farms: A GPS and LoRaWAN based case study on herbage intake and milk yield

Although grazing systems are widely used for lactating dairy cattle feed intake is generally lower than in a fully housed system even when the feed quality and animal’s nutritional requirements are similar. Here we investigate whether allocating additional herbage at a time linked to the cow’s behaviour can increase productivity using long range wide area network (LoRa) technology and GPS positioning to track animal activity and position. In particular, we examined whether additional herbage allowance increases daily herbage intake and milk production without compromising grazing efficiency. Fourteen trials were undertaken with commercial dairy herds in 2019, 2020 and 2021 with cows in mid to late lactation. The ‘GrazeMore’ additional grazing was compared to a standard daily herbage allocation. The ‘GrazeMore’ treatment period always followed an initial control period, sometimes with a subsequent control period. The composition of the herds was largely consistent over the duration of each trial, enabling the responses to be compared directly, though with an adjustment made for stage of lactation. Responses to additional ‘GrazeMore’ pasture allocations were inconsistent. Increased intakes during day grazing periods were sometimes balanced by reduced intakes in the following night periods, suggesting that factors other than the quantity of herbage on offer and the timing of its allocation during day grazing were responsible for limiting total 24h herbage intake and milk production. Synchronising additional pasture allocation with grazing behaviour does not always increase herbage intake and milk production.

Neural network applications to improve drift chamber track position measurements

This paper describes applications of two neural networks to improve drift chamber position measurements. One network calculates a data-driven estimate of the drift cell time-to-distance relationship that is conventionally estimated by a numerical calculation based on the anode and cathode wire geometry, wire potentials, and gas properties. The second network additionally uses the full digital waveform of the signal in the drift chamber, hence accessing information on the full ensemble of ionization clusters. This network uses more information than the conventional position estimate that relies exclusively on the arrival time of the first drift electron. In principle, this technique improves resolution even when multiple ionization clusters cannot be separated, in contrast with a cluster-counting technique. The performance of both networks when applied to MEG II drift chamber data is reported and compared to that of a conventional approach.

A virtual reference trajectory scheme for tracking control of wheeled mobile robots with slip disturbances

The problem of trajectory tracking control for wheeled mobile robots with slip disturbances is investigated in this paper. A virtual reference trajectory scheme is proposed based on disturbance compensations. Different from the conventional design philosophy of adding disturbance compensations to the controller, the proposed scheme integrates slip disturbance estimates into the reference trajectory. The proposed scheme consists of two parts. First, the slip disturbance estimates and the reference trajectory are fused to generate a virtual reference trajectory, where the slip disturbances are estimated using a disturbance approximation method. Second, a controller is designed to enable the wheeled mobile robot’s odometry position and yaw angle track the virtual reference trajectory, and then the actual position of the wheeled mobile robot track the position of the real reference trajectory. Comparison simulations and experiments are provided to illustrate the validity and advantages of the proposed scheme.

Comparative analysis of gender disparity in academic positions based on U.S. region and STEM discipline.

Despite a move toward gender parity in the United States (U.S.) workforce, a large gender gap persists in the fields of science, technology, engineering, and mathematics (STEM); this is particularly true for academic (i.e., instructor and tenure track) STEM positions. This gap increases as women advance through the traditional steps of academia, with the highest degree of gender disparity in tenured positions. As policies, politics, and culture, which all contribute to gender equity across the world, vary across regions in the United States, we expect that the gender gap in STEM might also vary across geographic regions. Here, we evaluated over 20,000 instructor and tenure track positions in university STEM departments across the U.S. to evaluate whether and how the geographic region of a university might determine its proportion of women in STEM academic positions. Similar to previous research, regardless of geographic region, more men were employed in both tenure track and instructor positions across STEM fields. However, variation existed regionally within the U.S., with the Mountain region employing the lowest proportion of women in tenure track positions and the East North Central and Pacific regions employing the greatest proportion. We expect this regional variation could be caused by differences in state and local policies, regional representation, and mentorship, resulting in inconsistent support for women, leading to differences in work environments, hiring, and job retention rates across the country. A better understanding of which geographic areas within the U.S. have more equal distributions of women in the STEM field will help us to identify the specific mechanisms that facilitate more equal and inclusive opportunities for women and other underrepresented groups across all levels of STEM academia.

Evolution of winter precipitation in the Nile river watershed since the last glacial

Abstract. Between 14.5 and 5 ka, the Sahara was vegetated owing to a wet climate during the African humid period. However, the climatic factors sustaining the “green Sahara” are still a matter of debate. Particularly the role of winter precipitation is poorly understood. Using the stable hydrogen isotopic composition (δD, where D stands for deuterium) of high molecular weight (HMW) n-alkanoic acids in a marine sediment core from the eastern Mediterranean, we provide a continuous record for winter precipitation in the Nile river delta spanning the past 18 kyr. Pairing the data with δD records from HMW n-alkanes from the same core, we show that HMW n-alkanoic acids constantly derived from the delta, while the HMW n-alkanes also received significant contributions from the headwaters between ∼ 15–1 ka when fluvial runoff enhanced. This enables us to reconstruct the evolution of Mediterranean (winter) and monsoonal (summer) rainfall in the Nile river watershed in parallel. In the delta, the Heinrich stadial 1 (HS1) evolved in two phases, with a dry episode between ∼ 17.5–16.0 ka, followed by wet conditions between ∼ 16–14.5 ka. Winter rainfall enhanced substantially between 11–6 ka, lagging behind the intensification of the summer monsoon by ca. 3 kyr. Heavy winter rainfall resulted from a southern position of the Atlantic storm track combined with elevated sea surface temperatures in the eastern Mediterranean, reinforcing local cyclogenesis. We show that during the green Sahara, monsoon precipitation and Mediterranean winter rainfall were both enhanced and infer that the winter rainfall zone extended southwards, delivering moisture to the Sahara. Our findings corroborate recent hypotheses suggesting that winter rains that extended southward were a crucial addition to the northward displacement of the summer monsoon in helping to sustain a green Sahara.

After Abu Dhabi: Restoring Integrity and Accountability in Formula 1

The 2021 Abu Dhabi Grand Prix ended the 2021 Formula One World Championship in a dramatic and controversial fashion. Mercedes’ Lewis Hamilton and Red Bull’s Max Verstappen went into the final round with an equal number of points scored for the World Drivers’ Championship. The race was decided in the final few laps after Williams’ Nicholas Latifi crashed into the barriers with five laps remaining. After the safety car was deployed, Verstappen pitted for a fresh set of soft tyres, while Hamilton stayed out to maintain track position. On the second-to-last lap, Race Director Michael Masi directed only the five lapped cars between Verstappen and Hamilton to unlap themselves, in direct contravention of established Fédération Internationale de l'Automobile (FIA) rules. On the final lap, the green flag was deployed and the race resumed; Verstappen overtook Hamilton on his fresher tyres and maintained the lead, going on to win the Grand Prix and consequently the World Drivers’ Championship. Mercedes initially filed protests for breach of sporting regulations, but eventually withdrew them, citing a loss of faith in racing and that what happened in Abu Dhabi was "not right."

The Infrared Auroral Footprint Tracks of Io, Europa and Ganymede at Jupiter Observed by Juno‐JIRAM

AbstractThe electromagnetic coupling between the Galilean satellites at Jupiter and the planetary ionosphere generates an auroral footprint, which is detected with high spatial resolution in the infrared L band by the Jovian InfraRed Auroral Mapper (JIRAM) onboard the Juno spacecraft. We report the JIRAM data acquired since 27 August 2016 until 23 May 2022, which are used to compute the average position of the footprint tracks of Io, Europa and Ganymede. The result of the present analysis help to test the reliability of magnetic field models, to calibrate ground‐based observations and to highlight the variability in the footprint positions, which can be used to probe the plasma environment at the orbit of the satellites. The determination of the plasma properties around the moons is particularly relevant to complement the Juno flybys of the moons during its extended mission, and to support the future Juice and Europa Clipper missions. Lastly, we report no clear evidence of the auroral footprint of Callisto, which is likely due to a combination of its low expected brightness and its position very close to the main Jovian aurora.

Stratospheric influence on the winter North Atlantic storm track in subseasonal reforecasts

Abstract. Extreme stratospheric polar vortex events, such as sudden stratospheric warmings (SSWs) or extremely strong polar vortex events, can have a significant impact on surface weather in winter. SSWs are most often associated with negative North Atlantic Oscillation (NAO) conditions, cold air outbreaks in the Arctic and a southward-shifted midlatitude storm track in the North Atlantic, while strong polar vortex events tend to be followed by a positive phase of the NAO, relatively warm conditions in the extratropics and a poleward-shifted storm track. Such changes in the storm track position and associated extratropical cyclone frequency over the North Atlantic and Europe can increase the risk of extreme windstorm, flooding or heavy snowfall over populated regions. Skillful predictions of the downward impact of stratospheric polar vortex extremes can therefore improve the predictability of extratropical winter storms on subseasonal timescales. However, there exists a strong inter-event variability in these downward impacts on the tropospheric storm track. Using ECMWF reanalysis data and reforecasts from the Subseasonal to Seasonal (S2S) Prediction Project database, we investigate the stratospheric influence on extratropical cyclones, identified with a cyclone detection algorithm. Following SSWs, there is an equatorward shift in cyclone frequency over the North Atlantic and Europe in reforecasts, and the opposite response is observed after strong polar vortex events, consistent with the response in reanalysis. However, although the response of cyclone frequency following SSWs with a canonical surface impact is typically captured well during weeks 1–4, less than 25 % of the reforecasts manage to capture the response following SSWs with a “non-canonical” impact. This suggests a possible overconfidence in the reforecasts with respect to reanalysis in predicting the canonical response after SSWs, although it only occurs in about two-thirds of the events. The cyclone forecasts following strong polar vortex events are generally more successful. Understanding the role of the stratosphere in subseasonal variability and predictability of storm tracks during winter can provide a key for reliable forecasts of midlatitude storms and their surface impacts.

Worlds apart? An empirical assessment of education as a social boundary among young people in Flanders

ABSTRACT Educational tracking refers to the grouping of students based on their academic abilities. Although tracking has been intensively debated in terms of its impact on academic outcomes, this study assesses whether educational tracks effectively constitute a social boundary between youth. Data from 11 surveys (Total N = 38,372) gathered among pupils enrolled in secondary education in Flanders were used to assess to what extent young people’s educational track position relates to a wide range of opinions and behavior in general (471 outcomes) and the potential moderating role of gender and migration status. Subsequently, we focused on indicators that refer to intergroup processes (i.e. cross-track friendships and perceived contempt). Educational differences are especially large for tastes, indicators of lifestyle, and societal attitudes. Moreover, we find that differences in educational track position are connected with perceived status differences and constitute an important structuring factor regarding their friendships.

Empirical and numerical-based predictive analysis of a single-axis PV system under semi-arid climate conditions of Pakistan

Power generation from fossil fuels is the biggest challenge in the next half of the century. Alternative power generation techniques such as solar photovoltaic (PV) show potential to act as a future fuel with a challenge to efficiently convert the harvested solar energy into electrical power. This investigation conclusively focused on setting a 2.160-kW solar PV system capable of working at a higher efficiency by developing a mechanical structure that optimizes power production and minimizes energy losses. In addition to that, solar PV system efficiencies at various tracking positions, performance coefficients during rainy and sunny days, and system degradation rates have also been investigated. The PVsyst v6.8 simulation tool was used to obtain the simulated results, which were compared with the actual experimental results. The parameters considered for the investigations include ambient temperature, irradiance, solar PV module surface temperature, solar PV voltage and current, wind velocity, and atmospheric turbidity. The solar PV system was evaluated based on two modes, namely, M1 (no tracking/fixed type) and M2 (manual tracking by changing the position of the solar PV system every hour). The predictive results obtained using PVsyst v6.8 concluded that total energy production from the installed system was 3,242 kWh/yr and 3,984 kWh/yr for M1 and M2, respectively. The performance ratio (PR), obtained from simulation, was 72% and 78% for M1 and M2, respectively, which was consistent with the experimental results, i.e., 70% and 72% for M1 and M2, respectively. Similarly, the power conversion efficiencies under standard temperature and conditions for both modes, simulated and experimental, were found to be 16.50% and 12.75%, respectively. The estimated degradation rate was observed in the range of −0.6% to −5.0%.

Dynamic characteristics of a compliant seat coupled with the human body and a manikin during the exposure to the whole-body vibration: Effect of the polyurethane foam, the track position, and the measurement location

Purpose Transmissibility is used to assess dynamic responses of the occupant-seat system, and most studies have exclusively assessed the transmissibility from the floor to the cushion or the backrest surface with the human body. Methods In this investigation, the vertical vibration transmitted from the floor to six specific locations both on the seat surface and the frame when the seat was fixed on three positions on the track was examined utilizing an SAE J826 manikin and 12 male adults (0.25 to 20 Hz) for a duration of 120 seconds at three vibration amplitudes. Results The transmissibility from the floor to the headrest frame, the cushion surface, the headrest surface, the seat back frame, and the seat back surface all exhibited a principal peak frequency within 4-5 Hz. With the exception of the cushion frame, the principal peak frequency and the peak transmissibility in transmissibilities to all positions decreased with increasing vibration amplitude, indicating the non-linearity within the occupant-seat system. It was also found modifying seat track positions minimally affected the seat transmissibility to either the surface or the frame of the seat. Conclusions Polyurethane foam amplified vibration at peak frequency, simultaneously enhancing static sitting comfort and reducing the vertical vibration transmission above peak frequency.

Uključivanje kretanja gornje i donje platforme - generalizovani inverzni kinematički model za simulaciju i eksperimentalno testiranje 6-ups Stjuart platforme

Due to accuracy and precision of parallel manipulators like Stewart platform, several technological applications have relied on them. An accurate kinematic model must be developed in order to improve the manipulator's accuracy. In this paper, inverse kinematic model investigation and verification have been accomplished. Conducting both upper and lower platforms under various motion types is a defining feature of this model. The 3D model of the platform has been directly linked to SimMechanics, paving the way for simulation analysis. MATLAB was used to code the obtained kinematic model. Workspace analysis of the platform has shown the permissible 3D range of each leg, and its intersection consists the total range of the upper platform. Simulation analysis has shown that, position track error hadn't exceeded 10% along any axis, while orientation error hadn't exceeded 2.32% about any axis. In the Experimental model test, the total average error in actuator's displacements is 0.094 cm, while the total average error in rotation angles is 1.145° .

Model-free scheme using time delay estimation with fixed-time FSMC for the nonlinear robot dynamics

<abstract><p>This paper presents a scheme of time-delay estimation (TDE) for unknown nonlinear robotic systems with uncertainty and external disturbances that utilizes fractional-order fixed-time sliding mode control (TDEFxFSMC). First, a detailed explanation and design concept of fractional-order fixed-time sliding mode control (FxFSMC) are provided. High performance tracking positions, non-chatter control inputs, and nonsingular fixed-time control are all realized with the FxSMC method. The proposed approach performs better and obtains superior performance when FxSMC is paired with fractional-order control. Furthermore, a TDE scheme is included in the suggested strategy to estimate the unknown nonlinear dynamics. Afterward, the suggested system's capacity to reach stability in fixed time is determined by using Lyapunov analyses. By showing the outcomes of the proposed technique applied to nonlinear robot dynamics, the efficacy of the recommended method is assessed, illustrated, and compared with the existing control scheme.</p></abstract>