Detection of Ground Contact Times with Inertial Sensors in Elite 100-m Sprints under Competitive Field Conditions

This study describes a method for extracting the stride parameter ground contact time (GCT) from inertial sensor signals in sprinting. Five elite athletes were equipped with inertial measurement units (IMU) on their ankles and performed 34 maximum 50 and 100-m sprints. The GCT of each step was estimated based on features of the recorded IMU signals. Additionally, a photo-electric measurement system covered a 50-m corridor of the track to generate ground truth data. This corridor was placed interchangeably at the first and the last 50-ms of the track. In total, 863 of 889 steps (97.08%) were detected correctly. On average, ground truth data were underestimated by 3.55 ms. The root mean square error of GCT was 7.97 ms. Error analyses showed that GCT at the beginning and the end of the sprint was classified with smaller errors. For single runs the visualization of step-by-step GCT was demonstrated as a new diagnostic instrument for sprint running. The results show the high potential of IMUs to provide the temporal parameter GCT for elite-level athletes.

Development of an electric measurement system for rapid determination of the friction coefficient

Development of an electric measurement system for rapid determination of the friction coefficient is discussed in this paper. The electric system is capable to use with a ball cage guide bush unit. Two beam load cells are included into the system and the measured values of the forces are processed by microcontrollers. In the course of measurements, normal- and tangential forces of inner or outer surfaces of different enamelled specimens could be determined. A data acquisition program is developed to record the force values to a personal computer. Linear interpolation method is required to synchronize the values of the load cells, which is necessary to calculate the coefficient of friction.

Implementasi Labview Untuk Pemantauan Pemakaian Energi Listrik

In conventional electric measurement devices, measurements are made on the use of electrical energy as a whole where consumers can only see information on the results of the use of electrical energy by looking at the total power consumption amount indicated on the meter kWh meter. Based on the above problems, the author aims to raise the title "Design of Monitoring System of Electricity Energy Usage using LabVIEW". The LabVIEW program has the ability to measure, monitor and store data quickly and accurately. With this tool will be realized a design system monitoring the use of electrical energy in real time through the computer instead of kWH meter analog or digital. This concept is one of the energy management solutions that enable consumers to obtain statistical data on electrical energy consumption in detail. From the results of monitoring the use of loads, obtained very good results in monitoring the usage of energy, which in this case using household burden.