To improve the signal-to-noise ratio (SNR) of vibration signals in a phase-sensitive optical time-domain reflectometer (Φ-OTDR) system, a principal component analysis variable step-size normalized ...least mean square (PCA-VSS-NLMS) denoising method was proposed in this study. First, the mathematical principle of the PCA-VSS-NLMS algorithm was constructed. This algorithm can adjust the input signal to achieve the best filter effect. Second, the effectiveness of the algorithm was verified via simulation, and the simulation results show that compared with the wavelet denoising (WD), Wiener filtering, variational mode decomposition (VMD), and variable step-size normalized least mean square (VSS-NLMS) algorithms, the PCA-VSS-NLMS algorithm can improve the SNR to 30.68 dB when the initial SNR is −1.23 dB. Finally, the PCA-VSS-NLMS algorithm was embedded into the built Φ-OTDR system, an 11.22 km fiber was measured, and PZT was added at 10.19–10.24 km to impose multiple sets of fixed-frequency disturbances. The experimental results show that the SNR of the vibration signal is 8.77 dB at 100 Hz and 0.07 s, and the SNR is improved to 26.17 dB after PCA-VSS-NLMS filtering; thus, the SNR is improved by 17.40 dB. This method can improve the SNR of the system’s position information without the need to change the existing hardware conditions, and it provides a new scheme for the detection and recognition of long-distance vibration signals.
Returning lysed sludge to biochemical tanks to achieve in-situ sludge reduction is promising. A novel approach for regulating and initiating the sludge lysis process utilizing thermophilic strains is ...proposed. In this study, three strains were isolated from sludge, and sequencing of the 16 S rDNA amplicon revealed that the three thermophilic strains were the closest relatives to the genus Geobacillus, and they were designated as Geobacillus sp. DX5, Geobacillus sp. DX8 and Geobacillus sp. DX11. Sludge lysis experiments demonstrated that composite thermophilic strains (CTS) were dosed at 65°C, and the sludge VSS removal efficiency after 24 h was 37.8%, significantly surpassing individual strains. Moreover, 65.8% of proteins and 52.0% of polysaccharides in Extracellular polymeric substances (EPS) of sludge were degraded. Furthermore, Three-dimensional excitation-emission matrix (3D-EEM) fluorescence spectroscopy results revealed a substantial release of dissolved organic matter during sludge lysis. Inoculation of CTS under optimal conditions (65°C, pH 7, 4 × 1010cfu/L) resulted in VSS removal efficiency and protease activity of 42.7% and 2584 U/L, respectively. After 20 days of inoculation with CTS to initiate sludge lysis reactor, VSS removal efficiency reached 46%. Additionally, it stimulated the growth of the thermophilic bacterial community, engaging indigenous thermophilic strains in the sludge lysis process.
Display omitted
•Three novel thermophilic bacterial strains were isolated from sludge.•Inoculated with CTS at 65 °C reduces sludge VSS by 36.8% within 24 hours.•CTS enables rapid initiation of the sludge lysis reactor.•Inoculation with CTS can rapidly adapt to the environment and colonize the sludge.
Scar contracture bands after burns are frequent problems that cause discomfort and physical limitation. This study investigates the efficacy of a minimally invasive contracture band release technique ...(MICBR) inspired by closed platysmotomy.
Patients with burn scars treated with MICBR in our center were included retrospectively. Our routine scar and contracture treatments (non-invasive and invasive) were utilized prior to undergoing MICBR. Range of motion (ROM) and Vancouver Scar Scale was measured before and after the procedure when feasible.
Forty-five patients were included, with 97 total contracture sites treated all over the body. An average of 1.6 sites were treated per patient, with a maximum of six. Patients age was 6–68 years; total burn surface area ranged from 0.5% to 85%. 24% were performed under local anesthesia. 84% were in originally skin grafted areas. We found significant improvements in ROM and VSS. 84% of patients surveyed were “satisfied” or “very satisfied”. 95% reported improved mobility. No significant adverse events occurred.
This MICBR technique is a versatile, safe, and well-tolerated adjunct procedure that can help patients regain mobility after a burn injury.
•Burn injuries can cause scar contractures that have severe functional consequences.•Minimally invasive contracture release can be performed on patients of any age or burn surface area.•This contracture release is safe and can be performed under local anesthesia.•Patients undergoing this contracture release had significant range-of-motion increases.•95% of patients reported improved mobility.
The only way for the Blind and visually impaired persons to read the holy Quran is by using a special paper edition of embossed Braille code. A new approach to reading the Holy Quran text for those ...persons was proposed by the author. One of the main demands for this approach is the classification of the dots and diacritics, which can be abbreviated as DaDs. This paper outlines the creation of a dataset of images for the DaDs of Al-Mushaf. A handheld scanner was developed for this purpose, and MATLAB programs were employed for DaDs segmentation. The final goal is the design of a tactile vision sensory substitution system based on an optical character recognition technique to help blind individuals read the Holy Quran in an alternative way to Braille codes. Approximately 1750 images were taken from two distinct Al-Mushaf versions with the proposed handheld scanner. Using the suggested techniques and algorithms, 6000 DaDs were retrieved from these images; however, only 4710 images of the DaDs, arranged in 22 classes, were selected after the repeated, incomplete, and non-DaDs were eliminated. The dataset was organized by DaD class, prepared to be used directly for machine learning purposes, and made available for public use upon request.
A viable technology for the future wireless communication system to obtain extremely high information rates with improved coverage is the collaborative incorporation of an intelligent reflecting ...surface (IRS) with millimeter-wave (mmWave) multiple-input multiple-output (MIMO) systems. An IRS provides a virtual line-of-sight (LoS) path to enhance the wireless system's capacity. However, accurate channel state information is essential for the complete utilization of IRS and mmWave MIMO systems. Existing channel estimators based on orthogonal matching pursuit (OMP) and sparse Bayesian learning (SBL) entail large pilot overhead and matrix inversion. Therefore, these techniques offer low spectral efficiency and high computational complexity. To overcome the limitations of existing estimators, we propose an online variable step-size zero-attracting least mean square (VSS-ZALMS) based algorithm for IRS-assisted mmWave hybrid MIMO system channel estimation. Further, we derive analytical expressions for the range of step-size and regularization parameters to improve estimation accuracy and convergence rates. Moreover, we conduct an analysis of IRS location, spectral efficiency, complexity analysis, and pilot overhead requirements. Simulation results are then compared with OMP, SBL, and oracle least square for benchmarking. The results corroborate superiority of the proposed approach concerning accuracy, complexity, and robustness compared to the existing estimators.
In the event of grid faults, the disconnection of a large capacity distributed generation (DG) may compromise grid stability. To address this challenge, grid codes in many countries have incorporated ...fault ride-through capability that requires the DG to remain connected to the grid for a stipulated time and regulate the voltage at the point of common coupling (PCC). A voltage support scheme (VSS) aims at restoring the PCC voltage within stipulated limits by injecting suitable currents. To restore the voltage under asymmetrical faults, a conventional VSS requires unequal current injection. As the phase current of the highest amplitude hits the rating of the inverter, the voltage support capability of the DG is compromised. The VSS proposed in this article aims to minimize the highest phase current while maintaining the same voltage support at PCC. The reduction in the highest phase current, in turn, provides reserve voltage support capability. The proposed scheme works well for all types of grid impedances, and the optimum points are found to be independent of the grid impedance. This independence of the optimum points simplifies the implementation of the proposed VSS. The simulation and experimental results demonstrate the effectiveness of the proposed VSS.
Power Quality (PQ) issue has always been a challenge for Grid-Interfaced PV Systems (GIPS). A novel Variable Step Size Robust Least Mean Logarithmic Square (VSS-RLMLS)-based control scheme is thus ...presented for a GIPS. In the proposed control scheme, the VSS-RLMLS algorithm extracts the fundamental components of the nonlinear load currents accurately even during dynamic conditions which results in generation of accurate reference grid current thus allowing efficient functioning of the Voltage Source Converter (VSC) and delivering high quality power to the grid by mitigating the harmonics of the loads. The performance of the proposed control scheme is validated both in simulation and laboratory developed prototype system with different load and environmental conditions. This VSS-RLMLS control scheme is compared with LMF and variable leaky LMS. It is found that the proposed control exhibits superior PQ performance with least grid current THD.
Intelligent transportation system (ITS) collects numerous data for analysis of the transportation system. The data can be used for providing services for travellers and traffic controllers in the ITS ...and optimizing it, for the purpose of making the transportation more efficient and safer. Due to the wide and flexible employment of video cameras in visual surveillance system (VSS), mature edge-cloud resource scheduling for data transmission and analysis, and the fast development of deep learning, computer vision (CV) methods have been employed in the visual-based ITS services successfully. In this paper, we discuss the edge-cloud surveillance resource scheduling for the CV methods and review the deep learning-based CV methods in the VSS, including detection, classification, and tracking methods, for better understanding of the relationship between the CV-based ITS services and these methods. We experimentally compare several state-of-the-art deep learning-based methods, which have been successfully applied in the CV fields under the ITS scenario, on their performance, inference speed, computational quantity, and model size. According to the comparisons, we propose four main challenges of the deep learning-based CV methods applied in the services, as a discussion of the future research directions. Code are available at https://github.com/PRIS-CV/DL-CV-ITS .
Conventional least-mean-square (LMS) algorithm is one of the most popular algorithms, which is widely used for adaptive beamforming. But the performance of the LMS algorithm degrades significantly ...because the constant step size is not suitable for varying signal-to-noise ratio (SNR) scenarios. Although numerous variable-step-size LMS (VSS-LMS) algorithms were proposed to improve the performance of the LMS algorithm; however, most of these VSS-LMS algorithms are either computationally complex or not reliable in practical scenarios since they depend on many parameters that are not easy to tune manually. In this letter, a fast and robust VSS-LMS algorithm is proposed for adaptive beamforming. The VSS is obtained based on normalized sigmoid function, where the sigmoid function is calculated by using the mean of instantaneous error first and then normalized by the squared cumulative sum of instantaneous error and estimated signal power. The proposed algorithm can update the step size adaptively without tuning any parameter and outperform state-of-the-art algorithms with low computational complexity. The simulation results show better performance of the proposed algorithm.
