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Upper limb analysis measured by inertial measurement unit tool: a case report

100%

Filip Wołoszyn F. , Anna Czmi A.

nr 1

94-100

Introduction. This article reports differences in accurate and inaccurate forehand and backhand strokes in tennis. The tests were carried out on a professional tennis player. The duration of a stroke, the heights of the individual segments of the right upper limb and differences in the heights of the segments at the beginning and at the end of every phase of stroke were examined. Aim. The major aim of the work was to expose upper limb disparity in stokes. Description of the case report. The research tool was inertial motion sensors (IMS) based on an accelerometer, a gyroscope and a magnetometer. A professional tennis player was examined using the individual case method and kinematic analysis. Results. The analysis concerned the average time to perform forehand and backhand strokes during all phases of the stroke, i.e. preparation, acceleration and follow-through phases. The average heights of the individual upper limb segments during a stroke were also taken into account. The results of the study are meant to show how the movement of the upper limb affects the accuracy and velocity of a stroke. Conclusion. The movements of individual segments in some accurate strokes were similar to those in inaccurate strokes.

Application of the Teager Kaiser Energy Operator in an autonomous burst detector to create onset and offset profiles of forearm muscles during reach-to-grasp movements

72%

Krabben T. , Prange G. B. , Kobus H. J. , Rietman J. S. , Buurke J. H.

tom Vol. 18, no. 4

135--144

Purpose: The primary aim of this study is to investigate the potential benefit of the Teager–Kaiser Energy Operator (TKEO) as data pre-processor, in an autonomous burst detection method to classify electromyographic signals of the (fore)arm and hand. For this purpose, optimal settings of the burst detector, leading to minimal detection errors, need to be known. Additionally, the burst detector is applied to real muscle activity recorded in healthy adults performing reach-to-grasp movements. Methods: The burst detector was based on the Approximated Generalized Likelihood Ratio (AGLR). Simulations with synthesized electromyographic (EMG) traces with known onset and offset times, yielded optimal settings for AGLR parameters “window width” and “threshold value” that minimized detection errors. Next, comparative simulations were done with and without TKEO data pre-processing. Correct working of the burst detector was verified by applying it to real surface EMG signals obtained from arm and hand muscles involved in a submaximal reach-to-grasp task, performed by healthy adults. Results: Minimal detection errors were found with a window width of 100 ms and a detection threshold of 15. Inclusion of the TKEO contributed significantly to a reduction of detection errors. Application of the autonomous burst detector to real data was feasible. Conclusions: The burst detector was able to classify muscle activation and create Muscle Onset Offset Profiles (MOOPs) autonomously from real EMG data, which allows objective comparison of MOOPs obtained from movement tasks performed in different conditions or from different populations. The TKEO contributed to improved performance and robustness of the burst detector.

Performance analysis of IRNSS using compact microstrip patch antenna for S band application

58%

Prajapati M. , Rawat A.

2020

tom Vol. 68, no. 4

1223--1228

The Indian Regional Navigation Satellite System (IRNSS) is a newly functional regional satellite navigation system around Indian subcontinent. It is also known as its functioning name of NaVIC, Navigation with Indian Constellation, working on L5 and S band. In this paper a compact and low cost circularly polarized microstrip patch antenna is proposed for IRNSS S band application, to provide single frequency navigation solution. Fabrication of proposed antenna is performed using substrate of RT Duroid 5880 with the dimensions of 0.66λ × 0.5λ. The performance of IRNSS is investigated by prototype antenna and Accord made triband antenna with IRNSS/GPS/SBAS receiver which is enable to receive L1, L5 and S band data. The comparison of proposed S band antenna, triband accord system antenna and GPS antenna is presented in terms of carrier to noise ratio and positioning error. Results show that proposed antenna is suitable for S band application of IRNSS receiver.