Breakage and damage of fiber optic cable fibers seriously affects the normal operation of fiber optic networks, and it is important to quickly and accurately determine the type and location of faults when they occur. Unlike the old traditional methods, the advantages of wavelet transform in singular signal detection and signal filtering are used to analyze the Optical Time Domain Reflectometer curve signal and the fault detection method of fiber communication links with no relay and a large span in a high altitude area is given, which realizes the accurate detection and location of optical fiber communication link fault events under strong noise. The proposed technology detects fiber optic faults in high-altitude environments, with an average measurement accuracy improvement of $9.8\%$. The maximum distance for detecting fiber optic line faults is up to 250 km, which increases the system power budget. In the simulation experiment results, the infrastructure nodes of the Wuhan FiberHome Laboratory successfully verified the superiority of this technology. The method has been directly applied to the on-site detection of ultra long optical fiber links in high-altitude areas, which has good financial significance and has certain reference significance for the future real-time detection of optical fiber cables.

Splicing loss of optical fibers has always been the focus of attention in engineering. With the construction of communication networks in high altitude areas, more attention has been paid to the fusion of optical fibers in high altitude areas. A mathematical model of single-mode optical fibers splice loss affected by altitude is established in this paper. The model takes the splice loss caused by the mismatch in mode field diameters (MFD), angular misalignment and lateral misalignment into account, as well as the influence of atmospheric pressure on splicing angular misalignment. Fiber fusion experiments are carried out at different altitudes. The proposed model validated by the experimental results and can be used as a reference to future research on the splice loss of single-mode fibers in plateau areas.

Up to now, there have been no complete theoretical researches and field experiment reports on the fiber fusion loss at high altitude. Therefore, we have conducted an exploratory study on the fiber splicing loss at high altitude, and firstly analyze the influence of mode field diameter mismatch, axial offset, angle tilt or end face gap affected by high altitude on splice loss, and then discuss the influence of fusion-splicing parameters on splice loss. Besides, a mathematical model for reducing the splicing loss of single-mode fiber at high altitude is established by combining the effects of temperature, humidity, oxygen content, atmospheric pressure, gale and gravity. We have conducted repeated field fusion experiments in different altitude areas (53, 2980, 4000, 4200, 4300, 5020, and 5200 m) more than once, hence obtaining a large number of field experimental data, making a deep comparison between typical “plain” area and typical “high altitude” area. The splice loss of most fusion points achieved successfully has been reduced by at least 0.07 dB. The simulation results are basically consistent with the theoretical analysis. Ultimately, the method proposed has been directly applied to on-site splicing engineering in high altitude environment and achieves good results.

Cognitive impairment is common but often overlooked in patients with inflammatory demyelinating diseases such as multiple sclerosis and neuromyelitis optica spectrum disorder. The conventional assessments may fail to detect subtle deficits and require substantial time and expertise. We collected neuropsychological scores and real-time handwriting data across nine drawing tasks and tasks from the Symbol Digit Modalities Test in 93 patients. Temporal, pressure, and kinematic features were extracted, and machine learning classifiers were trained using five-fold cross-validation with bootstrap confidence intervals. The response timing and pen pressure metrics correlated significantly with global cognitive scores (|r| = 0.30–0.37, p < 0.01). A support vector machine using eight selected features achieved an area under the receiver-operating characteristic curve (AUC) of 0.910, and a streamlined five-feature variant maintained an equivalent performance (AUC = 0.921) while reducing the assessment time by 35%. These results indicate that digital handwriting metrics can complement the standard screening by capturing fine motor and temporal characteristics overlooked in conventional testing. Validation in larger, disease-balanced, and longitudinal cohorts is needed to confirm their clinical utility.

Distributed space‐time block coding (STBC) is a promising technique for future broadband wireless communication system, because of its substantially improving the reliability of wireless channel by exploiting cooperative spatial diversity. In this study, the authors propose a novel two time slots distributed time‐reversal STBC scheme for amplify‐and‐forward relay‐assisted single‐carrier (SC) block transmissions over frequency‐selective fading channel. They first exploit the discrete Fourier transform extended properties to construct a linear precoding matrix. They then employ a low‐complexity suboptimal frequency domain decision feedback equalisation (FD‐DFE) to collect potential multipath diversity at high signal‐to‐noise ratio. Simulation results demonstrate that the proposed scheme provides better performance than the conventional distributed SC‐STBC scheme with minimum‐mean‐square error FD linear equalisation.