Moisture in the sensing coil of fiber-optic gyroscope (FOG) gives rise to bias drift. To explain and predict this phenomenon, one needs to quantify the strain along the fiber induced by moisture. In this paper, a full theoretical approach to determine the strain field into the sensing coil induced by a moisture loading is proposed. The approach consists in solving an analytical Fickian diffusion model in a semi-infinite medium, to implement a semi-analytical mechanical model of the moisture diffusion effect. The computed strain along the fiber is then compared with the distributed strain along the fiber measured using Rayleigh optical frequency domain reflectometry (Rayleigh-OFDR). Agreement between predicted and measured data demonstrate the validity of the proposed approach. Finally, a step function of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$60\%RH$</tex-math></inline-formula> (relative humidity) is shown to be equivalent to a thermal loading of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$1 \ ^{\circ }C/min$</tex-math></inline-formula> on <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\Delta T = 15 \ ^{\circ }C$</tex-math></inline-formula> and these loadings may induce an estimated bias of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$0.1 \ ^{\circ }/h$</tex-math></inline-formula> .

The method of Rayleigh-Optical Frequency Domain Reflectometry (Rayleigh-OFDR) has been used to estimate, at the component level, the thermal bias drift due the elasto-optic effect into a 400m-long self-standing quadrupolar coil, under a temperature ramp ranging from -20°C to 80°C. This estimation is performed before integration of the sensing coil in a Fiber-Optic Gyroscope (FOG). A theoretical reminder of how a thermal perturbation is creating a spurious bias in the FOG rotation rate measurement is described. Then, we propose a new methodology to estimate the thermal bias drift of the sensing coil before its assembly. It is based upon Rayleigh-OFDR. Uncertainties are characterized to assess the performances of the Rayleigh-OFDR to characterize the thermal bias drift due to <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">elasto-optic</i> effect in a FOG.

The paper introduces a general structure for parameter adaptation/learning algorithms (PALA). This structure is characterized by the presence of an embedded ARMA (poles-zeros) filter in the PALA. The key question is how to select the coefficients of this filter in order, on the one hand, to guarantee the stability of the parameter estimator for any (positive) value of the adaptation gain/learning rate and for any initial conditions and on the other hand to accelerate the adaptation transient. In order to achieve this, it is shown that on one hand the embedded ARMA filter should be characterized by a positive real transfer function and on the other hand the filter acting on the correcting term (the dynamic adaptation gain) should be characterized by a strictly positive real transfer function. Specific conditions for the design of a second order ARMA embedded filter (ARIMA2 algorithm) are provided.It is shown in the paper that many parameter adaptation/learning algorithms (PALA) used in adaptive control, system identification and neural networks (Nesterov, Conjugate gradients, Momentum back propagation, Averaged gradient, Integral+proportional+derivative, …) are particular cases of the PALA structure introduced in this paper and specific conditions for the stable operation of these algorithms are given.Performance of the ARIMA2 algorithm as well as of the other algorithms reviewed in the paper will be comparatively evaluated by simulations and experimental results obtained on an active noise control system.

ABSTRACT Purpose: Investigate acute locomotor, internal (heart rate (HR) and ratings of perceived exertion (RPE)) and neuromuscular responses to using wearable resistance loading for soccer-specific training. Methods: Twenty-six footballers from a French 5th division team completed a 9-week parallel-group training intervention (intervention group: n = 14, control: n = 12). The intervention group trained with wearable resistance (200-g on each posterior, distal-calf) for full-training sessions on Day + 2, D + 4 and unloaded on D + 5. Between-group differences in locomotor (GPS) and internal load were analyzed for full-training sessions and game simulation drills. Neuromuscular status was evaluated using pre- and post-training box-to-box runs. Data were analyzed using linear mixed-modelling, effect size ± 90% confidence limits (ES ± 90%CL) and magnitude-based decisions. Results: Full-training sessions: Relative to the control, the wearable resistance group showed greater total distance (ES [lower, upper limits]: 0.25 [0.06, 0.44]), sprint distance (0.27 [0.08, 0.46]) and mechanical work (0.32 [0.13, 0.51]). Small game simulation (<190 m2/player): wearable resistance group showed small decreases in mechanical work (0.45 [0.14, 0.76]) and moderately lower average HR (0.68 [0.02, 1.34]). Large game simulation (>190 m2/player): no meaningful between-group differences were observed for all variables. Training induced small to moderate neuromuscular fatigue increases during post-training compared to pre-training box-to-box runs for both groups (Wearable resistance:0.46 [0.31, 0.61], Control:0.73 [0.53, 0.93]). Conclusion: For full training, wearable resistance induced higher locomotor responses, without affecting internal responses. Locomotor and internal outputs varied in response to game simulation size. Football-specific training with wearable resistance did not impact neuromuscular status differently than unloaded training.

After Achilles tendon tenorraphy, tendon tissue undergoes a long period of biological healing. During this period, tissue turnover shows heterogeneity between its peripheral and central regions. This case report concerns the description of the tendon healing process of an athlete who underwent an Achilles tendon tenorraphy. As the reparative processes progressed, magnetic resonance imaging (MRI) showed centralization of the hyperintensity area and the tendon assumed a doughnut-like appearance. At the same time, ultrasound (US) assessment showed a progressive reorganization of the tendon fibrillar structure. Therefore, for the athlete, MRI and US assessment together represent a useful tool for the decision-making process after Achilles tendon tenorraphy.

The newly discovered cyphelloid species Chromocyphella meloana is here described and illustrated based on specimens collected in continental France. Hypothetic reproductive isolation of this species is supported by the morpholological characteristics of fruit bodies, which initially develop as corticioid basidiomes, and mature into folded, torn structures producing ellipsoid brown rugose basidiospores. A combination of ITS, 28S rDNA and rpb2 sequences is used to classify the collection as a new species within the genus Chromocyphella. A key to the species of Chromocyphella is provided.