A New Contact Mat Wireless System for Estimating Vertical Jump Height

Abstract Among the different devices available for the assessment of the vertical jump height based on the flight time measurement, the contact mats are surely one of the simplest and portable systems and, for this reason, they are more widely used. This paper deals with the comparative evaluation of the performances of a new contact mat system with respect to a force platform. Some tests have been performed and the relative comparative results will be presented. The study shows a significant concurrent validity of Wi-JumpLe system for the flight and ground contact time measurements. In conclusion, the new contact mat structure together with the electronic measurement system is legitimate to assess vertical jump height and leg extensors muscle power

Neural Network Modeling of Arbitrary Hysteresis Processes: Application to GO Ferromagnetic Steel

A computationally efficient hysteresis model, based on a standalone deep neural network, with the capability of reproducing the evolution of the magnetization under arbitrary excitations, is here presented and applied in the simulation of a commercial grain-oriented electrical steel sheet. The main novelty of the proposed approach is to embed the past history dependence, typical of hysteretic materials, in the neural net, and to illustrate an optimized training procedure. Firstly, an experimental investigation was carried out on a sample of commercial GO steel by means of an Epstein equipment, in agreement with the international standard. Then, the traditional Preisach model, identified only using three measured symmetric hysteresis loops, was exploited to generate the training set. Once the network was trained, it was validated with the reproduction of the other measured hysteresis loops and further hysteresis processes obtained by the Preisach simulations. The model implementation at a low level of abstraction shows a very high computational speed and minimal memory allocation, allowing a possible coupling with finite-element analysis (FEA)

Design of a Wireless Wereable DAQ System for the Evaluation of Sports Performances

An accurate monitoring of the professional athletes\u2019 exercises during training sessions is able to improve their performance by helping them in improving the effectiveness of the movement, in the injury prevention and in the rehabilitation protocols. Wearable and non-encumbrance DAQ (Digital Acquisition) systems are required because it is important to collect data from the athlete\u2019s performance in his natural environment rather than in the unspecific spaces of a laboratory. This paper deals with the design of a wireless data logger for the evaluation and analysis of the sport performance. In particular, the system is composed of a multichannel sEMG (surface Electromyography) system synchronized the kinematic signals obtained by an Inertial Measurement Unit (IMU) placed on the back of the athlete by the use of a belt. The system can be wirelessly connected with a proper terminal for data display and analysis

2D Video Analysis System to Analyze the Performance Model of Figure Roller Skating: A Pilot Study

Figure roller skating is a discipline composed of various movements which involve jumps, artistic figures and spins in a seamless program which has both technical and shapely difficult. A biomechanical analysis of a double salchow was performed using a 2D video analysis of one European and in two Italian roller skaters. On average, the high level (HL) roller skater showed a horizontal velocity of the center of mass higher than the average, especially in the prop stage, whereas the medium level (ML) and low level (LL) athletes reduced their velocity significantly. The spin angular velocity of the ML and LL skaters was always higher than of the HL. This phenomenon would seem to be a compensatory strategy for a lower jump height, with a reduced trunk-thigh angle and less thigh lever arm (coxo-femur/knee joints) during the take-off and landing phases of the double salchow jump

Power Flow Management by Active Nodes: A Case Study in Real Operating Conditions

The role of distributor system operators is experiencing a gradual but relevant change to include enhanced ancillary and energy dispatch services needed to manage the increased power provided by intermittent distributed generations in medium voltage networks. In this context, the paper proposes the insertion, in strategic points of the network, of specific power electronic systems, denoted as active nodes, which permit the remote controllability of the active and reactive power flow. Such capabilities, as a further benefit, enable the distributor system operators to provide ancillary network services without requiring any procurement with distributed generation systems owners. In particular, the paper highlights the benefits of active nodes, demonstrating their capabilities in reducing the inverse power flow issues from medium to high voltage lines focusing on a network cluster including renewable energy resources. As a further novelty, this study has accounted for a real cluster operated by the Italian distributor system operator Areti. A specific simulation model of the electrical lines has been implemented in DigSilent PowerFactory (DIgSILENT GmbH–Germany) software using real operating data obtained during a 1-year measurement campaign. A detailed cost-benefit analysis has been provided, accounting for different load flow scenarios. The results have demonstrated that the inclusion of active nodes can significantly reduce the drawbacks related to the reverse power flow

Search for heavy neutral lepton production in K+ decays

A search for heavy neutral lepton production in K + decays using a data sample collected with a minimum bias trigger by the NA62 experiment at CERN in 2015 is reported. Upper limits at the 10−7 to 10−6 level are established on the elements of the extended neutrino mixing matrix |Ue4| 2 and |Uμ4| 2 for heavy neutral lepton mass in the ranges 170–448 MeV/c2 and 250–373 MeV/c2, respectively. This improves on the previous limits from HNL production searches over the whole mass range considered for |Ue4|2 and above 300 MeV/c2 for |Uμ4|2

CNN cell for computing disparity map

The real-time estimation of the distance of objects from an observer is a critical issue in several application fields. A new cellular neural network circuit that uses a stereo vision algorithm to compute the disparity map is presented

A Matlab Simulink model for the study of smart grid — Grid-integrated vehicles interactions

The market of electrical vehicles is in continuous expansion. When the number of the full electrical or hybrid vehicles will be significant, they could represent an interesting further resource of electrical storage in an intermittent renewable power sources scenario. The focus of this paper is to describe a MATLAB Simulink model well suited for the analysis of the behavior of a car park of electric vehicles used as energy storage in a smart grid environment