Location Of Ball Research Articles

Observer effect, quasi-probabilities and generalized Specker's boxes.

Quantum non-locality and contextuality can be simulated with quasi-probabilities, i.e. probabilities that take negative values. Here, we show that another quantum phenomenon, the observer effect, admits a quasi-probabilistic description too. We also investigate post-quantum observer effects based on the Specker's triangle scenario. This scenario comprises three observables, with the possibility of measuring two simultaneously. Represented as three boxes with a hidden ball, this scenario exhibits counterintuitive behaviour: regardless of the chosen pair of boxes, one box always contains the ball. Moreover, the scenario demonstrates a strong observer effect. When an observer selects and opens the first box, finding it empty, the ball is guaranteed to be in the second box, thereby allowing the observer to determine the ball's location among the remaining two boxes. We extend this scenario to include additional boxes and multiple balls. By employing negative probabilities, we demonstrate amplification of the observer effect. This article is part of the theme issue 'Quantum contextuality, causality and freedom of choice'.

Opponent Hitting Behavior Prediction and Ball Location Control for a Table Tennis Robot.

The hitting position and velocity control for table tennis robots have been investigated widely in the literature. However, most of the studies conducted do not consider the opponent's hitting behaviors, which may reduce hitting accuracy. This paper proposes a new table tennis robot framework that returns the ball based on the opponent's hitting behaviors. Specifically, we classify the opponent's hitting behaviors into four categories: forehand attacking, forehand rubbing, backhand attacking, and backhand rubbing. A tailor-made mechanical structure that consists of a robot arm and a two-dimensional slide rail is developed such that the robot can reach large workspaces. Additionally, a visual module is incorporated to enable the robot to capture opponent motion sequences. Based on the opponent's hitting behaviors and the predicted ball trajectory, smooth and stable control of the robot's hitting motion can be obtained by applying quintic polynomial trajectory planning. Moreover, a motion control strategy is devised for the robot to return the ball to the desired location. Extensive experimental results are presented to demonstrate the effectiveness of the proposed strategy.

Effects of Voids on Thermal Fatigue Reliability of Solder Joints on Inner Rings in Ball Grid Array Packaging by Finite Element Analysis

Under alternating temperatures, the fatigue failure of solder balls caused by the mismatch of the thermal expansion coefficient is a key problem in a Ball Grid Array (BGA). However, the combined effects of the solder ball location and the size of voids within it can seriously affect the thermal fatigue reliability of BGA solder balls, which can be easily ignored by researchers. Firstly, the thermal fatigue reliability of the board-level solder balls was evaluated by a temperature cycling test of the BGA package at -20 °C-+125 °C. The experimental results showed that the thermal fatigue reliability of the outer ring's solder joint was lower than that of the inner ring. Secondly, the reliability of the solder balls in the BGA package was studied under the same thermal cycling condition based on finite element analysis (FEA). The influences of voids on fatigue life were investigated. Generally, a linear correlation between the void content and the fatigue life of the inner rings' solder balls could be identified with a gradually smoothed relationship for solder balls closer to the center. In addition, when the size of the void exceeded a critical volume, the inner ring's solder ball with the void would fail before the outermost ring. The results of FEA showed that the critical void volume ratio from the second to fifth ring increased from 10.5% to 42.3%. This study provides a valuable reference for the influence of voids on the thermal fatigue reliability of BGA solder balls.

The Impact of the Connection Failure of Ground Solder Balls on Digital Signal Waveform

Ball-grid array (BGA) packages are widely used in digital signal devices, whose reliability and signal integrity are critical. In this research, the impact of failed ground solder balls on digital signal waveforms was theoretically modeled and analyzed, and the results were experimentally verified. A 3-D electromagnetic field model of a digital signal transmission channel with failed ground solder balls was developed to analyze the signal transmission in the frequency domain. In addition, a time-domain waveform simulation system was developed to examine the changes in the digital signal waveforms before and after degradation. Based on the structural and signal transmission characteristics of the solder area with failed ground solder balls, an equivalent circuit model of the degraded solder area was developed, which accurately predicts the effect of the failed ground solder balls on the amplitude and rising edge of the digital signals. The results obtained from the simulation were validated using experimental tests. This study fully examines the effects of the location and number of failed ground solder ball on signal transmission in both the frequency and the time domain. It provides insight and guidance regarding the impact on signal integrity of such faults, which serves to assist in improved packaging reliability and the development of fault detection strategies for such electronic systems.

Mobile robot vision navigation strategy based on Pixy2 camera

This paper aims to present an efficient navigation method for collecting tennis balls using a visual sensor, specifically the Pixy2 camera, which, in addition to the sensor, also has a high-quality processor built in. In order to achieve this goal, a navigation algorithm based on three situations encountered in practice when detecting a tennis ball was developed and the information received from the Pixy2 camera, that is width, height and two coordinates on the x-axis and y-axis was processed. Basically, two hypotheses were considered, namely: area decides the order and object coordination defines the choice of navigation strategy. Using a square consisting of 100x100 [mm] gray squares, the navigation method was validated based on a visual sensor, by studying five individual and representative cases of tennis ball location. For each case, the four data provided by the sensor were collected and then processed in order to highlight the two hypotheses initially established.

Nature exposure might be the intervention to improve the self-regulation and skilled performance in mentally fatigue athletes: A narrative review and conceptual framework.

BackgroundDue to causing inability of self-regulation (ego depletion) and executive functions such as directed attention and visual searching for relevant information (e.g., the ball location and the position of teammates), mental fatigue impairs skilled performance in various sports. On the other hand, natural scenes could improve directed attention, which may considerably benefit visual searching ability and self-regulation. However, nature exposure as a potential intervention to improve skilled performance among mentally fatigued athletes has not been discussed thoroughly.PurposeTo propose the potential intervention for the impairment of skilled performance among mentally fatigued athletes and generate a framework for future studies.MethodsA narrative review was applied to search broadly across disciplines, retrieving literature from several databases (PubMed, Web of Science, Scopus, and EBSCOhost).ResultsThirty-three works of literature including 39 experiments (mental fatigue 15; ego depletion 5; and nature exposure 19) were obtained. Finally, a conceptual framework was built regarding the effect of nature exposure intervention on skilled performance in athletes for future studies.ConclusionThree theories (the psychobiological model of exercise performance, the strength model of self-regulation, and attention restoration theory) could be potentially integrated to be a conceptual framework and explain the mechanism of preventing prior mental exertion (e.g., mental fatigue and ego depletion). Future studies could examine more on the duration of the intervention.

Context modulates the impact of auditory information on visual anticipation

Research on the impact of auditory information on visual anticipation in tennis suggests that the intensity of racket-ball-contact sounds systematically biases estimates of the ball’s speed, thereby influencing anticipatory judgments. Here we examined whether the effect of auditory information on visual anticipation is dependent on the sport-specific context in two separate experiments. In Exp. 1, participants watched short videos of tennis rallies that were occluded at racket-ball-contact. Racket-ball-contact sounds of the final shot were either present or absent. Participants faced different tasks in two counterbalanced blocks: In one block they estimated the ball’s speed; in the other block they indicated the ball’s landing location. Results showed that participants estimated longer ball flight trajectories and higher ball speeds in the sound present condition than in the sound absent condition. To probe whether this effect is dependent on the sport-specific context, Exp. 2 introduced an abstract (i.e., context-free) version of the previous stimuli. Based on the ball locations in the original videos used in Exp. 1, we rendered new videos that displayed only a moving circle against a blank background. Sine tones replaced the original racket-ball contact sounds. Results showed no impact of sound presence on location anticipation judgments. However, similar to Exp. 1, object speeds were judged to be faster when the final sound was present. Together, these findings suggest that the impact of auditory information on anticipation does not seem to be driven by sound alone, but to be moderated by contextual information.

Prediction of the Ball Location on the 2D Plane in Football Using Optical Tracking Data

Tracking the ball location is essential for automated game analysis in complex ball-centered team sports such as football. However, it has always been a challenge for image processing-based techniques because the players and other factors often occlude the view of the ball. This study proposes an automated machine learning-based method for predicting the ball location from players' behavior on the pitch. The model has been built by processing spatial information of players acquired from optical tracking data. Optical tracking data include samples from 300 matches of the 2017-2018 season of the Turkish Football Federation's Super League. We use neural networks to predict the ball location in 2D axes. The average coefficient of determination of the ball tracking model on the test set both for the x-axis and the y-axis is accordingly 79% and 92%, where the mean absolute error is 7.56 meters for the x-axis and 5.01 meters for the y-axis.

Reference values for collective tactical behaviours based on positional data in professional football matches: a systematic review.

Match collective tactical behaviours can be used as a reference to design and select training strategies to improve individual and team performance in professional football. The aim of the systematic review was to cluster the collective tactical variables used to highlight and compare male soccer teams’ collective behaviour during professional official matches, providing reference values for each of them. A systematic review of relevant articles was carried out using three electronic databases (PubMed, SPORTdiscus and Web of Science). From a total of 1,187 studies initially found, 13 original articles were included in the qualitative synthesis. The articles found concerned studies carried out on the Spanish, Portuguese, English and Brazilian 1st divisions and during the European UEFA Champions League. The team length and width ranged from 31 to 46 m and from 35 to 48 m, respectively. The distance from a defending team’s goalkeeper to the nearest teammate ranged from 9 ± 6 to 30 ± 7 m, the goal line-recovery location from 27 to 37 m, and the opponent’s goal line from 42 to 50 m. The stretch index ranged from 7 to 16 m. Mean team area was ~900 m2 and the area of the pitch which included all outfield players divided by the 20 outfield players ranged from 79 ± 15 to 94 ± 16 m2. All studies provided greater distance and area values during the team-possession phase in comparison to the non-possession one. The ball location on the pitch determined the collective tactical behaviour of the teams. The differences between halves in the distance and area values were contradictory. Further studies should assess the effect of the interaction between the contextual factors on the collective tactical behaviour to obtain more accurate references. This could help football coaches in the design of suitable training tasks to optimize tactical performance.

Team numerical advantage in Australian rules football: A missing piece of the scoring puzzle?

The primary aim of this study was to determine the relationship between a team numerical advantage during structured phases of play and match event outcomes in professional Australian football. The secondary aim was to quantify how players occupy different sub-areas of the playing field in match play, while accounting for match phase and ball location. Spatiotemporal player tracking data and play-by-play event data from professional players and teams were collected from the 2019 Australian Football League season played at a single stadium. Logistic regression analysed the relationship between total players and team numerical advantage during clearances and inside 50’s. Total players and team numerical advantage were also quantified continuously throughout a match, which were separated into three match phases (offence, defence, and stoppage) and four field positions (defensive 50, defensive midfield, attacking midfield, and forward 50). Results identified an increased team numerical advantage produced a greater likelihood of gaining possession from clearances or generating a score from inside 50’s. Although, an increased number of total players inside 50 was likely associated with a concomitant decrease in the probability of scoring, irrespective of a team numerical advantage. Teams were largely outnumbered when the ball was in their forward 50 but attained a numerical advantage when the ball was in the defensive 50.

Are you missing a concussion by watching American football? Video analysis of ball location in a Division 1 football program

ABSTRACT Objective Action in a football game occurs quickly. Medical staff can miss a sport-related concussion (SRC) if they do not observe it directly. The objective of this study is to determine if SRCs occur more frequently at ball than away from ball during gameplay. Game-specific concussion statistics can enhance medical provider care of athletes. Methods We used gameplay videos of an NCAA Division I football program to analyze SRCs and determine the primary tackler or ball handler during each concussion play. We compared the relative risk of SRCs for the primary ball handlers/tacklers to that of the other 10 players on the same team during that play. Results Over 10 seasons, 26 SRCs occurred at ball for the primary ball handler/tackler position (0.22 SRCs/game) versus 16 away from ball (0.13 SRCs/game). The relative risk of an SRC according to exposure (at ball) vs. no exposure (away from ball) was 16.2 (CI 8.7–30.2, P < .05). Special teams had more SRCs away from ball than at ball, but this was not significant (relative risk 3.32, CI 0.90–12.3, P > .05). Conclusions The study provides medical staff guidance to more efficiently identify in-game SRCs and supports evidence for rules changes.

A Study of Human Balance and Coordination Using a Head Mounted Display

Abstract This paper reports on an experiment in human subject balance and coordination using a HTC Vive head mounted display to create a virtual environment. For the experiment, 30 male human subjects of college age and 30 female subjects of college age were asked to navigate along a clear path in a virtual world using a controller with their dominant hand and asked to balance a virtual ball on a virtual plate using the other controller in the non-dominant hand. The test subjects moved along a clearly marked path, with three surprise obstacles occurring: a large rock landing near the path, and explosion near the path, and a flock of birds coming across the path. Data included 6 degree of freedom trajectories for the head, and both hands, as well as data gathered by the computer system on ball location and velocity, plate location and velocity and ball status. Likert scale questionnaires were answered by the test subjects relative to video game experience, sense of presence, and ease of managing the ball movement. Statistics showed that the male students dropped the ball less frequently at p = 0.0254 and p = 0.0036. In contrast, female students were aware of their performance with correlation levels of 0.632 and 0.588.

Risk factors for abdominal wall pseudohernia after percutaneous cryoablation of renal cell carcinoma.

IntroductionPercutaneous cryoablation (PCA) is increasingly recognized as a feasible minimally invasive, nephron-sparing treatment for renal cell carcinomas, with comparable efficacy to nephrectomy. The development of abdominal wall pseudohernia (AWP) is a rare complication of PCA for renal masses, which can negatively impact patients’ quality of life.AimTo retrospectively evaluate the risk factors and prognosis for AWP after PCA and, based on these results, to discuss strategies to lower the risk of AWP associated with image-guided PCA for renal masses.Material and methodsWe retrospectively studied 117 PCAs performed for renal masses in 92 patients, between 2016 and 2019, at our hospital. We compared the following clinical characteristics (age, sex, body mass index, tumour diameter, RENAL nephrometry score, procedural details, transcatheter arterial embolization, dissection techniques, number of cryoneedles used, location of needles, and location of ice ball) between those who developed AWP and those who did not.ResultsOf the 117 PCAs (92 patients) included in our study group, AWP complications were observed in 6 (5.1%) procedures. Puncture through the erector spinae muscle (p < 0.01) and non-use of hydro- or pneumo-dissection (p = 0.01) were identified as risk factors for AWP.ConclusionsAlthough PCA is relatively safe to perform and the occurrence of an associated AWP is a rare and infrequent complication, the risk for AWP could be further decreased by avoiding punctures through the erector spinae muscle and using hydro- or pneumo-dissection.

Comparison of Postoperative Results According to Fungus Ball Extension in Maxillary Sinus

Background and Objectives Fungus ball is the most common type of fungal sinusitis commonly associated with good prognosis. However, postoperative results depending on the extent of the lesion has not been investigated. This study aimed to identify differences in postoperative results depending on the location and extent of the fungus ball.Subjects and Method Medical records of 165 patients who underwent endoscopic sinus surgery and who were diagnosed with fungus balls by biopsy from 2010 to 2019 were retrospectively reviewed. Patients were classified into four grades according to the location and extent of the fungus ball based on their endoscopic and CT findings. Poor outcome is defined as any pathologic signs such as nasal secretion, granulation, and polyps or narrowing of the natural ostium observed postoperatively according to Kennedy’s criteria, whereas good outcome is defined as absence of pathologic signs.Results A total of 23 patients were Grade 1, 38 Grade 2, 67 Grade 3, and 37 Grade 4. Grades 1 and 2 were mostly asymptomatic. However, as the location of the fungus ball became closer to the natural ostium, patients complained postnasal drip and purulent discharge. Grades 3 and 4, who have much severe and more extensive lesions than those of Grades 1 and 2, had poor outcome (&lt;i&gt;p&lt;/i&gt;=0.007) and took longer time to completely recover (&lt;i&gt;p&lt;/i&gt;&lt;0.001).Conclusion Wound healing was delayed and poor when the fungus ball was located closer to the natural ostium of the maxillary sinus. Therefore, preoperative consultation using endoscopic and CT findings could be useful for predicting their postoperative results.

Temporally Coupled Coordination of Eye and Body Movements in Baseball Batting for a Wide Range of Ball Speeds.

We investigated the visuomotor strategies of baseball batting, in particular, the relationship between eye and body (head and hip) movements during batting for a wide range of ball speeds. Nine college baseball players participated in the experiment and hit balls projected by a pitching machine operating at four different ball speeds (80, 100, 120, 140 km/h). Eye movements were measured with a wearable eye tracker, and body movements were measured with an optical motion capture system. In the early period of the ball's flight, batters foveated the ball with overshooting head movements in the direction of the ball's flight while compensating for the overshooting head movements with eye movements for the two slower ball speeds (80 and 100 km/h) and only head rotations for the two faster ball speeds (120 and 140 km/h). After that, batters made a predictive saccade and a quick head rotation to the future ball position before the angular velocity of the ball drastically increased. We also found that regardless of the ball speed, the onsets of the predictive saccade and the quick head movement were temporally aligned with the bat-ball contact and rotation of the hip (swing motion), but were not correlated with the elapsed time from the ball's release or the ball's location. These results indicate that the gaze movements in baseball batting are not solely driven by external visual information (ball position or velocity) but are determined in relation to other body movements.

The informational properties of the throwing arm for anticipation of goal-directed action.

We examined the informational value of biological motion from the arm in predicting the location of a thrown ball. In three experiments, participants were classified as being skilled and less skilled based on their actual performance on the task (i.e., using a within-task criterion). We then presented participants with a range of stick figure representations and required them to predict throw direction. In Experiment 1, we presented stick figure movies of a full body throwing action, right throwing arm plus left shoulder and throwing arm only. Participants were able to anticipate throw direction above chance under all conditions irrespective of perceptual skill level, with the perceptually skilled participants excelling under full body conditions. In Experiment 2, we neutralized dynamical differences in motion to opposing throw directions from the shoulder, elbow and wrist of the throwing arm. Neutralizing the wrist location negatively affected anticipation performance in all participants reducing accuracy to below chance. In Experiment 3, we presented movies of the motion wrist location alone and the upper section of the throwing arm (shoulder-elbow). Participants were able to successfully anticipate above chance in these latter two conditions. Our findings suggest that motion of the throwing arm contains multiple sources of information that can help facilitate the anticipation of goal-directed action. Perceptually skilled participants were superior in extracting informational value from motion at both the local and global levels when compared to less skilled counterparts.

Three-Dimensional Pressure Profile of the Lower Esophageal Sphincter and Crural Diaphragm in Patients with Achalasia Esophagus

Smooth muscles of the lower esophageal sphincter (LES) and skeletal muscle of the crural diaphragm (esophagus hiatus) provide the sphincter mechanisms at the esophagogastric junction (EGJ). We investigated differences in the 3-dimensional (3D) pressure profile of the LES and hiatal contraction between healthy subjects and patients with achalasia esophagus. We performed a prospective study of 10 healthy subjects (controls; 7 male; mean age, 60 ± 15 years; mean body mass index, 25 ± 2) and 12 patients with a diagnosis of achalasia (7 male; mean age, 63 ± 13 years; mean body mass index, 26 ± 1), enrolled at a gastroenterology clinic. Participants underwent 3D high-resolution manometry (3DHRM) with a catheter equipped with 96 transducers (for the EGJ pressure recording). A 0.5-mm metal ball was taped close to the transducer number 1 of the 3DHRM catheter. EGJ pressure was recorded at end-expiration (LES pressure) and at the peak of forced inspiration (hiatal contraction). Computed tomography (CT) scans were performed to localize the circumferential location of the metal ball on the catheter. Esophagus, LES, stomach, right and left crus of the diaphragm, and spine were segmented in each CT scan slice images to construct the 3D morphology of the region. The metal ball was located at the 7 o'clock position in all controls. The circumferential orientation of metal ball was displaced 45 to 90 degrees in patients with achalasia compared with controls. The 3D-pressure profile of the EGJ at end-expiration and forced inspiration revealed marked differences between the groups. The LES turns to the left as it entered from the chest into the abdomen, forming an angle between the spine and LES. The spine-LES angle was smaller in patients with achalasia (104°) compared with controls (124°). Five of the 10 subjects with achalasia had physical breaks in the left crus of the diaphragm CONCLUSIONS: Besides LES, the 3D pressure profile of the EGJ can indicate anatomic and functional abnormalities of the crural diaphragm muscle in patients with achalasia esophagus. Further studies are needed to define the nature of hiatal and crural diaphragm dysfunction in patients with achalasia of the esophagus.

Online sonification for golf putting gesture: reduced variability of motor behaviour and perceptual judgement.

This study investigates whether real-time auditory feedback has a direct behavioural or perceptual effect on novices performing a golf putting task with limited visual feedback. Due to its significant role in the success of a putt, club head speed was selected as the parameter for sonification. Different combinations of synthesisers, timbral modulations, scales, and mappings were developed to examine whether particular sound classes influenced performance. When compared to trials with static pink noise, we found that, despite their vision being limited at impact, participants were able to use different types of sonification to significantly reduce variability in their distance from the target and ball location estimation. These results suggest that concurrent sound can play an important role in reducing variability in behavioural performance and related perceptual estimations. In addition, we found that, when compared to trials with static pink noise, participants were able to use sonification to significantly lower their average impact velocity. In the discussion, we offer some trends and observations relative to the different sound synthesis parameters and their effects on behavioural and perceptual performance.

Finite Element Analysis for Indentation Formation Process of Angular Contact Ball Bearing for Space Equipment under Impulsive Vibration

Impulsive vibration during rocket launch has the risk of causing indentations inside the bearings of reaction wheel mounted on a satellite. The indentations induce the vibration disturbance during the bearing rotation, which is harmful to precision equipment. In order to investigate the mechanism of the indentation formation, we carried out the experiments and finite element simulation for simplified reaction wheel. Based on the results of simulation, we estimated the depth of plastic deformation and wear using Palmgren’s formula and PV value, respectively. The indentation depth of simulation shows good agreements with that of experiment. The results also show that the wear between balls and rings is dominant factor of indentation formation, as compared with the plastic deformation. The amount of wear is greatly affected by the location of ball. In the location where the contact direction between ring and ball is parallel to the vibration direction, contact pressure contributes the wear as compared with slip velocity. Inversely, in the location where the contact direction is perpendicular to the vibration direction, the slip velocity contributes the wear and induces the larger wear region.

Fourteen- to Eighteen-Month-Old Infants Use Explicit Linguistic Information to Update an Agent's False Belief.

The current research examined how infants exploit linguistic information to update an agent’s false belief about an object’s location. Fourteen- to eighteen-month-old infants first watched a series of events involving two agents, a ball, and two containers (a box and a cup). Agent1 repeatedly acted on the ball and then put it in the box in the presence of agent2. Then agent1 disappeared from the scene and agent2 switched the ball’s location from the box to the cup. Upon agent1’s return, agent2 told her, “The ball is in the cup!” Agent1 then reached for either the cup (cup event) or the box (box event). The infants looked reliably longer if shown the box event as opposed to the cup event. However, when agent2 simply said, “The ball and the cup!” – which does not explicitly mention the ball’s new location – infants looked significantly longer if shown the cup event as opposed the box event. These findings thus provide new evidence for false-belief understanding in infancy and suggest that infants expect an agent’s false belief to be updated only by explicit verbal information.