Abstract
The purpose of the study was to examine the reliability, factorial validity evidence, invariance (by gender, type of sport and competitive level) and evidence of convergent validity of the CSAI-2. The total sample consisted of 375 athletes (284 males and 91 females). For evidence of convergent validity, the sample consisted of 163 athletes (115 males and 48 females). The athletes responded to the instruments (CSAI-2 and reduced version of the State Trait Anxiety Inventory - STAI) an hour before starting competitions. The results showed reliability (alpha > .70) and good indices of fit (CFI = .959, GFI = .942 and RMSEA = .044) for the reduced model of 17 items (CSAI-2R). The invariance and the evidence of convergent validity were supported. The Brazilian reduced version of CSAI-2 showed good psychometric properties, supporting its use in Brazilian athletes.

Abstract

Abstract

Abstract
This work focuses on the evaluation of different sensing techniques for the detection of wireless microphones in the UHF band, by means of simulation. The metrics used for the comparisons include probability of detection, probability of false alarm and minimum SNR detected for a given observation time. The energy detector is used as a benchmark against blind detection techniques. As an example, simulation results showed that blind detection algorithms can sense a wireless microphone signal with SNR = -17 dB in a Rayleigh channel, considering 100 ms sensing time, 90 % probability of detection and 10 % probability of false alarm.

Abstract

Abstract
This article describes an experimental testbed that combines wireless microphone sensors with a web-based terrestrial digital video broadcasting geolocation database and a program making and special events spectrumbooking platform. Software defined radio and Internet technologies are the enabling tools in use. The key sensing techniques are identified and implemented. Test trials in a real scenario have shown that the platform was able to receive information from a DVB-T geolocation database and a PMSE spectrum-booking platform, updating the list of vacant channels with blind sensing techniques. The proposed method has shown capabilities to protect primary users of interferences from secondary users of the spectrum. © 2012 IEEE.