In this research, the performance and movements of amateur and professional cyclists were analyzed. For this, reflective markers have been used on different parts of the body of the participants in ...conjunction with sports cameras and a mobile power meter. The trajectories of the markers have been obtained with the software Kinovea and subsequently analyzed using error ellipses. It is demonstrated that the error ellipses help determine movement patterns in the knees, back, and hip. The covariance of the error ellipses can be indicative of the alignment and symmetry of the frontal movement of the knees. In addition, it allows verifying the alignment of the spine and the symmetry of the hip. Finally, it is shown that it is necessary to consider the uncertainty of the power devices since it considerably affects the evaluation of the cyclists' performance. Devices with high uncertainty will demand a greater effort from the cyclist to meet the power required in the endurance test developed. The statistical magnitudes considered help to analyze power and evaluate the cyclists' performance.
•Lightning Detection Network median error ellipses often misinterpreted and used in “binary” manner in forensic investigations.•A methodology to investigate the effectiveness of this practice is ...explained.•South African Lightning Detection Network data compared with photographed ground-truth lightning events.•The method demonstrates how median error ellipse do not always include the location of attachment.
Lightning Detection Networks (LDNs) are sometimes used to investigate the possibility of lightning attachment to a specific geographic location for forensic investigations. When the time of the event to be investigated is unknown, the reported location of detected strokes and the measurement of their accuracy (median error ellipses) become the only LDN parameters available to determine whether lightning attached to a location or not. However, the information provided by the median error ellipses is often misinterpreted and the investigation only involves determining whether the median error ellipse includes the location of interest. In this paper, a reproducible methodology for investigating the effectiveness of using median error ellipses in this manner to determine if lightning attached to a specific geographic location is established. The methodology is applied to a case study – the Brixton tower, South Africa – and it is found that 40% of strokes detected as part of a flash that attached to the Brixton tower have median error ellipses including the location of the tower. Zero strokes that were detected as part of a flash that attached to another location had median error ellipses including the location of the tower. Concerns about using lightning events to tall towers for such an event are discussed.
In tennis, the serve is the shot of greatest importance. The serve depends mainly on the player's technique, however, environmental factors can influence the accuracy of the serve. This study ...highlights the effect of side wind on the serve of 12 experienced tennis players. The players were asked to hit the intersection point between the central and the service line at maximum speed while a wind effect was artificially generated by a ventilator setup with various speed of Induced Aerodynamic Flow (IAF). Each player's serve was then analyzed using error ellipses as a statistical measure. This method allowed us to evaluate the effect of "random wind" in comparison to "constant wind" on the accuracy of the serves. The truncated Fourier series analysis showed that there was an adaptive pattern in the accuracy of the serve depending on the random wind. However in four players, the more unpredictable the impact of the wind the more accurate they became with the serve. The fact that there was not a linear trend in the accuracy of serves when IAF increased shows that each player adapts differently to the wind influence.
For USBL (Ultra short Baseline), the positioning precision is a significant technical index. How to use the data gained in field trail to evaluate the precision has become an important problem that ...the USBL users pay more attention to. This paper used error ellipses theory to evaluate the USBL positioning precision, and after analyzing and computing, verified the conclusion that the error ellipse is equivalent to the statistical results corresponding to the 39.35% of the positioning points and then established a connection between the theoretical error model and the actual statistical results. Therefore, with the correct prior errors information, the USBL positioning precision evaluation can be performed with one of the USBL error ellipses. When the actual data is polluted by system errors, USBL theoretical error ellipse is not consistent with the statistical results of the scatter points. On this occasion, the error ellipse can be a criterion to evaluate system errors. In the last, according to the analysis for the results, this paper made a summary about the method used to evaluate USBL positioning precision combining error ellipse theory and actual positioning scatter points. That is, using the statistical value of the 39.95% of the positioning scatter points as the system precision and the theoretical error ellipse to evaluate the system error. Application has been achieved in the field trail to process data.
Many traditional mobile telemetry systems require permanently mounting a rod through the cabin of a vehicle to serve as the mast for a directional antenna. In this article we present an alternative ...to this configuration by providing a platform that can be placed atop the vehicle in which the antenna mast can be mounted and controlled from the cabin of the vehicle. Thereby making this design a viable option for researchers who share vehicles with others that may not approve of permanent vehicle modifications such as placing a hole in the roof of the vehicle as required by traditional mobile configurations. We tested the precision and accuracy of detachable mobile and adjustable telemetry system (DMATS) in an urban park with varying terrain, tree stands, overhead wires, and other structures that can contribute to signal deflection. We placed three radiocollars 50 m apart and 1.2 m above the ground then established three testing stations ~280 m from the location of the radiocollars. The DMATS platform required 12 h for completion and cost $1059 USD. Four technicians were randomly assigned radio collars to triangulate using DMATS and a handheld telemetry system. We used a one‐way analysis of variance (ANOVA) with a Scheffe post hoc test to compare error ellipses between azimuths taken using DMATS and the hand held system. Average error ellipses for all testers was 1.96 ± 1.22 ha. No significant differences were found between error ellipses of testers (P = 0.292). Our design, the DMATS, does not require any vehicle modification; thereby, making this a viable option for researchers sharing vehicles with others that may not approve of permanent vehicle alterations.
In this article we present an alternative to this configuration by providing a platform that can be placed atop the vehicle in which the antenna mast can be mounted and controlled from the cabin of the vehicle.
PDF
