Shooting Conditions Research Articles

Influence of Fatigue and Defensive Pressure on Three-Point Jump-Shot Kinematics in Basketball

This study examines the influence of fatigue and defensive pressure on the kinematic parameters of the three-point jump shot in basketball. Fourteen male collegiate basketball players (age: 21 ± 3 years old, body height: 186.35 ± 7.02 cm, body mass: 82.20 ± 10.99) participated in the study. Each participant performed three-point jump shots under four conditions: without defense, with defense, without defense after a fatigue protocol, and with defense after a fatigue protocol. Kinematic data were collected using the Xsens MVN inertial suit system and the OptoJump Next system. The analysis focused on various parameters including jump height, center of mass, release height, shoulder angle, and segment velocities. The repeated-measures ANOVA was used to observe the differences between each shot condition (fatigue, defense). Results indicated significant changes in the kinematic parameters due to both fatigue and defensive pressure. Fatigue notably changed shooting performance, affecting jump height and release mechanics. The defensive pressure altered shooting technique, leading to quicker ball release and higher release points. These findings highlight the importance of incorporating fatigue and defensive scenarios in training, suggesting that coaches develop more targeted training plans to improve performance under conditions of fatigue and defensive pressure.

Meta-learning with deep flow kernel network for few shot cross-domain remaining useful life prediction

Reliable prediction of the remaining useful life (RUL) is important for improving maintenance efficiency, equipment availability, and avoiding catastrophic accidents in complex industrial systems. Existing RUL prediction models have made some contribution, relying mainly on a large amount of degraded data with similar patterns or approximate distributions. However, in practical industrial systems, only a small amount of labeling data is usually available, which may also come from different devices and different working conditions, resulting in different distributions in the degraded data. This situation makes the existing RUL methods difficult to achieve satisfactory generalization performance. To address this challenge, this paper proposes a novel Meta-Learning with Deep Flow Kernel Network (MetaDFKN) model for RUL prediction under the few shot and cross-domain conditions. The model first learns kernel features in a data-driven manner and considers them as latent variables to improve the model’s representative ability of shared knowledge between tasks. Then, we introduce the conditional normalized flow technique to infer richer posterior distributions in the kernel features, which helps to obtain feature information with stronger discriminative power. Moreover, shared knowledge and task-specific information are integrated into the contextual inference process, which can mine the dependencies of related tasks and capture richer domain information. Finally, to evaluate the proposed model, we conduct extensive experiments on engine and bearings degradation data, and the results verify the superiority of the model.

A novel metric-based model with the ability of zero-shot learning for intelligent fault diagnosis

Intelligent fault diagnosis plays an important role in maintaining the safe and reliable operation of rotating machinery. However, the data collected in real engineering scenarios may be severely insufficient, which presents challenges to the intelligent fault diagnosis methods. To address this problem, this paper introduces a metric-based meta learning approach for gear fault diagnosis under zero shot conditions. Firstly, a gear-rotor dynamics model is established to simulate the vibration signals under different fault conditions. And the signals are converted into energy maps through wavelet transformation to provide frequency domain fault features. Secondly, a deep convolutional network is employed as the feature extraction module to construct the prototype representations by calculating the average embedding within each fault class. Then, the distances between the actual signals collected from the gear test rig and the class prototypes are computed. Finally, the softmax is applied to convert these distances into probability distributions for outputting the predicted fault classes. Furthermore, label smoothing technology is introduced to mitigate the probability distribution differences between simulated signals and real signals. The experimental results demonstrate that the average diagnostic accuracy of the proposed model reaches 98.9%, which is better than other models.

Speech emotion recognition based on meta-transfer learning with domain adaption

Deep learning often requires large amounts of labeled data to train the model, which is not always readily available in the field of speech emotion recognition (SER). Related research work on SER in few shot conditions has reported problem with overfifitting and domain transfer of training. In this study, a few-shot learning method based on meta-transfer learning with domain adaption (MTLDA) is proposed for SER. It not only effectively reduces the over-fitting phenomenon of deep neural networks (DNN) trained with a small number of samples, but also solves the forgetting problem in meta-learning and the target domain adaptability problem in transfer learning. Experiments on three databases (i.e., CASIA is used for pre-training, Emo-DB and SAVEE are used for few-shot learning) are performed for few-shot learning of SER, from which the WAR is 65.12% and UAR is 64.50% on Emo-DB, and the WAR is 58.84% and UAR is 53.26% on SAVEE.

Актуальные вопросы систематизации научных знаний об условиях выстрела в судебной баллистике

In this research, there was considered a challenge of constructing a system of scientific knowledge of the shot conditions in judicial ballistics. It was observed that there are underlying factors that are intended to ensureits [scientific knowledge] consistency: identification of the list of shot conditions, which require consideration when solving expert-level research tasks on weapons, cartridges and traces of their action; determination of the communication systems in the course of objects’ interaction, which present the result of exposure to the conditions of the shot; classification of the shot conditions based on the grounds significant for solving scientific and practical problems. The article contains the characteristics of a constructive, functional factor (condition) of weapons and cartridges influence, environmental and fire factors, the structure of the target and its physical properties, situational and spatial factors, and projectile energy characteristics. Highlighted are the forms of connections formed in the course of objects’ interaction, proposed are the author’s classifications of forensically significant shooting conditions with them being divided on the basis of the following criteria: production from the object of interaction, production from a natural phenomenon, production method, results weapon operation and utilization, duration of exposure, type of structural connections between interaction objects, number of conditions that apply when firing and the forming traces.

Establishing Shot Type Affects Arousal and Cognitive Load During Transitions Between Novel Interior Locations in Films.

An “establishing shot” prefaces a scene in a movie with a wide shot of the scene’s location. It is meant to help viewers process a shift to a new location. Establishing shots can depict the actors in the space in which they will be acting, the exterior of a building, or the larger geographic context of the scene. While use of an establishing shot is standard filmmaking practice, some argue that establishing shots are unnecessary. This study sought to investigate how effective four types of establishing shots are at helping viewers process location shifts. Pupil diameter was recorded using a MangoldVision eye tracking system as a measure of arousal and cognitive load. Oxygenation levels in the prefrontal cortex provided an additional measure of cognitive load assessed through functional near infrared spectroscopy (fNIRS). We expected scene transitions to be followed by transient increases in pupil diameter and oxygenation levels, suggesting increased cognitive load and arousal. We predicted that participants should experience less cognitive load and arousal after a transition to a new scene when that scene has been prefaced with an establishing shot and that these effects would be greatest for establishing shots that depict actors. We found that geographic establishing shots produced significantly lower average pupil diameter than all other establishing shot types and the use of no establishing shot. Actors establishing shots elicited significantly lower average pupil diameter values than the use of no establishing shot. Maximum and average oxygenation values for the actors establishing shot condition were significantly higher than for the exterior establishing shot condition. An alpha level of 0.05 was used for all analyses. These results suggest differences between pupil diameter and fNIRS in terms of the psychological phenomenon they measure, and may inform the design of future films.

Al 박육 다이캐스팅 주물에서 기포결함에 미치는 주물두께, 사출속도의 영향

The Al die casting process has been widely used in the manufacturing of automotive parts when the process requires near-net shape casting and a high productive rate. However, porosity arises in the casting process, and this hampers the wider use of this method for the creation of high-durability automotive components. The porosity can be controlled by the shot condition, but, it is critical to set the shot condition in the sleeve, and it remains difficult to optimize the shot condition to avoid air entrapment efficiently. In this study, the 4.5 mm, 2.0 mm plate die castings were fabricated under various shot conditions, such as plunger velocities of 0.7 m/s ~ 3.0 m/s and fast shot set points of the cavity of -25%, 0%, 25%, and 50%. The mold filling behavior of Al melts in the cavity was analyzed by a numerical method. Also, according to the shot conditions, the results of numerical analyses were compared to those of die-casting experiments. The porosity levels of the plate castings were analyzed by X-ray CT images and by density and microstructural analyses. The effects of the porosity on the mechanical properties were analyzed by tensile tests and hardness tests. The simulation results are in good general agreements with the die-casting experimental results. When plunger velocity and fast shot set point are 1.0 m/s and cavity 25% position, castings had optimum condition for good mechanical properties and a low level of porosity.

Vacuum Die Casting Process and Simulation for Manufacturing 0.8 mm-Thick Aluminum Plate with Four Maze Shapes

Using vacuum die casting, 0.8 mm-thick plates in complicated shapes are manufactured with the highly castable aluminum alloy Silafont-36 (AlSi9MgMn). The sizes and shapes of the cavities, made of thin plates, feature four different mazes. To investigate formability and mechanical properties by shot condition, a total of six parameters (melt temperatures of 730 °C and 710 °C; plunger speeds of 3.0 m/s and 2.5 m/s; vacuum pressure of 250 mbar and no vacuum) are varied in experiments, and corresponding simulations are performed. Simulation results obtained through MAGMA software show similar tendencies to those of the experiments. When the melt pouring temperature is set to 730 °C rather than 710 °C, formability and mechanical properties are superior, and when the plunger speed is set to 3.0 m/s rather than to 2.5 m/s, a fine, even structure is obtained with better mechanical properties. The non-vacuumed sample is half unfilled. The tensile strength and elongation of the sample fabricated under a melt temperature of 730 °C, plunger speed of 3.0 m/s, and vacuum pressure of 250 mbar are 265 MPa and 8.5%, respectively.

Counterbalancing the use of ultrasound contrast agents by a cavitation-regulated system

The stochastic behavior of cavitation can lead to major problems of initiation and maintenance of cavitation during sonication, responsible of poor reproducibility of US-induced bioeffects in the context of sonoporation for instance. To overcome these disadvantages, the injection of ultrasound contrast agents as cavitation nuclei ensures fast initiation and lower acoustic intensities required for cavitation activity. More recently, regulated-cavitation devices based on the real-time modulation of the applied acoustic intensity have shown their potential to maintain a stable cavitation state during an ultrasonic shot, in continuous or pulsed wave conditions. In this paper is investigated the interest, in terms of cavitation activity, of using such regulated-cavitation device or injecting ultrasound contrast agents in the sonicated medium. When using fixed applied acoustic intensity, results showed that introducing ultrasound contrast agents increases reproducibility of cavitation activity (coefficient of variation 62% and 22% without and with UCA, respectively).Moreover, the use of the regulated-cavitation device ensures a given cavitation activity (coefficient of variation less 0.4% in presence of UCAs or not). This highlights the interest of controlling cavitation over time to free cavitation-based application from the use of UCAs. Interestingly, during a one minute sonication, while ultrasound contrast agents progressively disappear, the regulated-cavitation device counterbalance their destruction to sustain a stable inertial cavitation activity.

Regulation of reaction forces during the golf swing

During the golf swing, the reaction forces applied at the feet control translation and rotation of the body–club system. In this study, we hypothesized that skilled players using a 6-iron would regulate shot distance by scaling the magnitude of the resultant horizontal reaction force applied to the each foot with minimal modifications in force direction. Skilled players (n = 12) hit golf balls using a 6-iron. Shot distance was varied by hitting the ball as they would normally and when reducing shot distance using the same club. During each swing, reaction forces were measured using dual force plates (1200 Hz) and three-dimensional kinematics were simultaneously captured (110 Hz). The results indicate that, on average, the peak resultant horizontal reaction forces of the target leg were significantly less than normal (5%, p < 0.05) when reducing shot distance. No significant differences in the orientation of the peak resultant horizontal reaction forces were observed. Resultant horizontal reaction force–angle relationships within leg and temporal relationships between target and rear legs during the swing were consistent within player across shot conditions. Regulation of force magnitude with minimal modification in force direction is expected to provide advantages from muscle activation, coordination, and performance points of view.

Pre-Current Effects on Basketball Free-Throw Shooting Accuracy

In this study, first and second free-throw pre-shot routines were considered as ”pre-current operant.” The result of the first free-throw shooting was a ”pre-current result” for the second free-throw shooting. Based on variables related to time series, this study was designed to examine the effects of pre-current operant and pre-current result on basketball free-throw shooting accuracy. Data were collected during the 2004 UBA Semi-final and Finals games. The videotape observation included 144 times of free-throw in 9 games. The measures included time of pre-shot routine and the number of free-throws made scores by each player in two free-throw shot conditions. The pre-shot interval of free-throw was transformed into z scores and was divided into ”short,” ”medium” and ”long” pre-shot intervals. ”Hit” or ”missed” groups were categoried, according to the result of the first performance of 2 free-throws, in order to define effect of pre-current results. The inter-rater and intra-rater reliability were r = .86 and r = .88. Independent t-test and one-way ANOVA were utilized to analyze between groups difference. The findings were as follows: 1. for accuracy of free-throw shooting, significant difference was found on pre-current result (p ＜ .05), in that ”hit” group was higher than ”missed” group; 2. for accuracy of free-throw shooting, no significant difference was found in pre-current operant (p ＞ .05). The conclusions of this study: 1. pre-current result has effect on the accuracy of free-throw shooting, and 2. pre-current operant has no effect on the accuracy of free-throw shooting.

Individual differences in VWM capacity assessed by the flicker task

Here we demonstrate that the flicker change detection paradigm provides a more stable estimate of individual differences in visual working memory (VWM) capacity than the more typical “one shot” paradigm. Recent excitement has surrounded the drive to understand individual differences in VWM capacity, as these differences may be a locus for broader impacts throughout cognition. In our study, participants completed 240 or 480 trials of either a one shot or a flicker task, during which they were presented with displays containing 2,4, or 8 colored squares. The one shot condition used standard parameters from published papers and capacity was estimated using Cowan's K. In the flicker condition, participants saw these same displays with the memory and change displays alternating until the changing stimulus was found and capacity was estimated using Rensink's RT-based estimate. Capacity estimates were generated for each set size and compared. Reliability of capacity estimates were assessed via split-half correlation and revealed significantly higher reliability for flicker than for one shot. Dramatically, after 10 minutes of testing (the amount used in many published papers with the one shot task), split-half correlation for one shot was non-significant (R2 = .01), suggesting little to no reliability in its estimate of individual differences in VWM capacity, while split-half correlation for flicker was significant (R2 = .63). When the number of trials in the task was doubled, one shot began to produce significant split-half correlations. A likely source of the difference between these tasks is that the flicker task requires the subject to deploy VWM capacity many times during a single trial allowing for a more stable estimate of VWM capacity. Concerns about search behavior in the flicker task remain (e.g., is it random with or without replacement or something in between) and further comparison of these two paradigms seems warranted.

Dynamic simulation and preliminary finite element analysis of gunshot wounds to the human mandible

ObjectiveDue to the complications arising from gunshot wounds to the maxillofacial region, traditional models of gunshot wounds cannot meet our research needs. In this study, we established a finite element model and conducted preliminary simulation and analysis to determine the injury mechanism and degree of damage for gunshot wounds to the human mandible. MethodsBased on a previously developed modelling method that used animal experiments and internal parameters, digital computed tomography data for the human mandible were used to establish a three-dimensional finite element model of the human mandible. The mechanism by which a gunshot injures the mandible was dynamically simulated under different shot conditions. First, the residual velocities of the shootings using different projectiles at varying entry angles and impact velocities were calculated. Second, the energy losses of the projectiles and the rates of energy loss after exiting the mandible were calculated. Finally, the data were compared and analysed. ResultsThe dynamic processes involved in gunshot wounds to the human mandible were successfully simulated using two projectiles, three impact velocities, and three entry angles. The stress distributions in different parts of mandible after injury were also simulated. Based on the computation and analysis of the modelling data, we found that the injury severity of the mandible and the injury efficiency of the projectiles differ under different injury conditions. ConclusionsThe finite element model has many advantages for the analysis of ballistic wounds, and is expected to become an improved model for studying maxillofacial gunshot wounds.

Design Method and Effect Analysis of 3D Block Acquisition Geometry in Loess Plateau

The huge thick loess plateau has the characteristic of dry, loose, high attenuation for seismic wave, and it's hard to get high S/N ratio data. According to the practical condition of survey area, the survey area was divided and 3-d block acquisition geometry was designed to acquire seismic data. after improving shot condition, optimizing acquisition geometry, increasing fold times and using multi-domain iteration static correction, the result showed that the block acquisition geometry and shot condition choosing were proper for data acquisition geometry and the S/N ratio of acquired data was high. The data processing procedure was suitable for data process, and the final result was good.

Elite golfers' kinematic sequence in full-swing and partial-swing shots

The aim of this study was to investigate whether kinematic proximal-to-distal sequencing (PDS) and speed-summation are common characteristics of both partial and full-swing shots in golf players of different skill levels and genders. A total of 45 golfers participated, 11 male tournament professionals, 21 male and 13 female elite amateurs. They performed partial shots with a wedge to targets at three submaximal distances, 40, 55 and 70 m, and full-swing shots with a 5 iron and a driver for maximal distance. Pelvis, upper torso and hand movements were recorded in 3D with an electromagnetic tracking system (Polhemus Liberty) at 240 Hz and the magnitude of the resultant angular velocity vector of each segment was computed. The results showed a significant proximal-to-distal temporal relationship and a concomitant successive increase in maximum (peak) segment angular speed in every shot condition for both genders and levels of expertise. A proximal-to-distal utilization of interaction torques is indicated. Using a common PDS movement strategy in partial and full-swing golf shots appears beneficial from mechanical and control points of view and could serve the purpose of providing both high speed and accuracy.

Relaxation of Residual Stress Part 2: Relaxation of Stage 2

Problem statement: Compressive residual stress induced by surface treatment such as shot peening increased component’s fatigue life. However the initial induced residual stresses relax during component operating life and it is important to consider the relaxation in the design. Approach: In this study, a 2024-T351 aluminum alloy specimens were shot peened into three shot peening intensities condition to induce compressive residual stresses. Then fatigue test for two loads was performed for the 10, 1000 and 10000 cyclic loads. The initial residual stresses at the initial condition and after 10, 1000 and 10000 cycle of fatigue loading were measured using X-ray diffraction method. Results: The results showed that the relaxation of the residual stress for the load 15.5 kN is less than the relaxation of the load 30 kN for the three shot peening intensity. The maximum relaxation for load 15.5 kN is 46% of the initial residual stress at 10000 cycles for intensity 0.009 A while the maximum relaxation for load 30 kN is 54% at 10000 cycles for the intensity of 0.0054% A. this result indicated that the residual stress relaxation depended on the load amplitude. Conclusion: The initial residual stress did not remain stable during the component’s fatigue life. Within the second phase relaxation, micro-plastic strains accumulating from cycle to cycle. The residual stress relaxation for second phase is in logarithmic relationship.

Hugoniot measurement by hyper-velocity impact at velocities up to 9 km/s using a two-stage light-gas gun under optimized shot conditions

Abstract The optimization for acceleration of a projectile was performed by varying piston mass in consideration with the correlation with projectile mass and the engineering limits of the two-stage light-gas gun, and the projectile velocity has been achieved 9.2 km/s using the optimum acceleration conditions. Moreover, the Hugoniot measurements of oxygen-free copper were performed using the line reflection method at pressures up to 380 GPa by symmetric impact. The tilt and curvature of shock front were investigated according to the impact velocity, and it is proved to be important that the continuous spatial profile of shock front would be recorded.

Lining of Carbon Steel with Metal Foils by Shot Peening

A lining process for carbon steel using shot peening was investigated. In the shot peening experiment, the dissimilar foil set on the carbon steel substrate is pelted with many shots at a high velocity. The foil is bonded to the surface of the substrate due to plastic deformation induced by the collision of the shots. In the experiment, an air-type shot peening machine with an electrical heater was employed. The substrates are commercially carbon steel S45C, and the foils are commercially pure aluminum, pure copper, and pure nickel. The effects of shot conditions and the heating temperature on the joinability were examined. To improve surface characteristics such as wear resistance and corrosion resistance, the surface alloying of the lined workpiece was also attempted. The metal foils were successfully joined to the surface of the substrate. It was found that surface properties of carbon steel could be improved by the shot lining process.

Effects of Trust Training on Tee and Pitch Shots in Golf

This study assessed the effects of a training program designed to enhance trust in the performance of a full swing tee shot and a greenside pitch shot using a repeated measures design with a cohort group. Skilled golfers with an average age of 21.3 years, average golf experience of 11.6 years, and a USGA handicap index of less than 7.0 served as participants. Following baseline performance assessment of six pitch shots, each participant completed a 2-day trust training program. Post-training measurements were taken during blocks of 10 trials for each test shot condition, a 25 m (30-yd) greenside pitch shot and a full swing tee shot with a driver, at 1 and 2 weeks following training Dependent measures included effective distance from a target, self-report measures of tempo, target and trust; process measures of last look at target to backswing start; and body position measures using both digital video and the GolfTEC system Statistical analyses revealed that tempo, target, hip and shoulder tilt were significant predictors of trust, while tempo and trust were significant predictors of effective distance. Results for the pitch shot revealed that when golfers trusted their swing, tempo was rated high and they hit their target, resulting in a 60% improvement in getting closer to the hole. Results for the tee shot suggest that when subjects trusted their swing and tempo was rated one interval higher than when they didn't trust their swing, effective driving distance increased an average of 18.3 m (20 yards). These results suggest that when skilled golfers access trust, their execution of golf shots markedly improves.

Laser Megajoule Cryogenic Target: A Path from Automatic Transfer to Laser Shot Conditions

The Laser Megajoule (LMJ) Cryotarget Positioner (PCC) will be used to set cryogenic targets in the vacuum chamber centre of this experimental facility for fusion by inertial confinement. In the French concept, only the targets will be transferred at cryogenic temperature to the PCC, using a Cryotarget Transfer Unit (UTCC). Some of the specifications are very ambitious. Indeed, the targets must be transferred automatically between those cryorobots, at a temperature between 20 K and 29 K. Then, they have to be cooled carefully by the PCC to the triple point (TP) of deuterium-tritium mixture at a rate of 0.5 mK/min. Just below the TP they have to be regulated with an accuracy of +/- 2 mK. Eventually, the DT mixture has to be set 1.5 K below the TP.Scale one prototypes of the cryostats have been built at the Low Temperature Laboratory (SBT) in CEA-Grenoble, France, to deal with specific issues: cryogenic contact resistances, fine cryogenic temperature regulation, test of the feasibility of various thermodynamic paths, 6 degrees of freedom robot positioner, vision control of the transfer and automation. This paper presents the results obtained with these prototypes regarding topics specific to cryogenic transfers, followed by very fine regulation of temperature around 20 K and by dynamic quenching just before the laser shot.