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Keywords = low-floor train

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19 pages, 8142 KiB  
Article
Recommendations for Planting Sites and Cultivation Modes Suitable for High-Quality ‘Cuiguan’ Pear in Jiangxi Province
by Yanting Li, Sichao Yang, Chuanyong Xiong, Yun Wang, Xinlong Hu, Chaohua Zhou and Lei Xu
Horticulturae 2025, 11(7), 771; https://doi.org/10.3390/horticulturae11070771 - 2 Jul 2025
Viewed by 255
Abstract
The ecological region and training system are critical in determining an orchard’s microclimate and, ultimately, the quality and yield of the fruit produced. However, few studies have addressed the effects of their interactions on the commodity properties preferred by consumers, including appearance, flavor, [...] Read more.
The ecological region and training system are critical in determining an orchard’s microclimate and, ultimately, the quality and yield of the fruit produced. However, few studies have addressed the effects of their interactions on the commodity properties preferred by consumers, including appearance, flavor, and nutritional components. This study was conducted in distinct ecological regions at the county scale, with two classic cultivation modes (a traditional freestanding system with natural grassing and fruit without bagging and a flat-type trellis system with floor covering and fruit bagging) used for investigation and testing in 2020 and 2024, respectively. Significant differences in internal and external quality attributes were observed between the two groups. A sensory analysis showed that an increase in the soluble solid content and a better fruit appearance were strongly associated with higher purchase intentions. By integrating meteorological parameters, it was also found that temperature and air humidity during the month before harvest were associated with the pear phytochemical and metabolomic profiles. Planting site had a particularly notable effect on quality attributes and sensory experience, with low-latitude-harvested samples under cultivation mode 1 clustering together and showing higher overall scores, while cultivation mode 2 may be more suitable for high-latitude areas. Our results pave the way for making precise recommendations for the selection of suitable planting sites and optimum cultivation modes in Jiangxi Province to achieve high-quality ‘Cuiguan’ pears and fully exploit their planting potential. Full article
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23 pages, 3907 KiB  
Article
Woodot: An AI-Driven Mobile Robotic System for Sustainable Defect Repair in Custom Glulam Beams
by Pierpaolo Ruttico, Federico Bordoni and Matteo Deval
Sustainability 2025, 17(12), 5574; https://doi.org/10.3390/su17125574 - 17 Jun 2025
Viewed by 444
Abstract
Defect repair on custom-curved glulam beams is still performed manually because knots are irregular, numerous, and located on elements that cannot pass through linear production lines, limiting the scalability of timber-based architecture. This study presents Woodot, an autonomous mobile robotic platform that combines [...] Read more.
Defect repair on custom-curved glulam beams is still performed manually because knots are irregular, numerous, and located on elements that cannot pass through linear production lines, limiting the scalability of timber-based architecture. This study presents Woodot, an autonomous mobile robotic platform that combines an omnidirectional rover, a six-dof collaborative arm, and a fine-tuned Segment Anything computer vision pipeline to identify, mill, and plug surface knots on geometrically variable beams. The perception model was trained on a purpose-built micro-dataset and reached an F1 score of 0.69 on independent test images, while the integrated system located defects with a 4.3 mm mean positional error. Full repair cycles averaged 74 s per knot, reducing processing time by more than 60% compared with skilled manual operations, and achieved flush plug placement in 87% of trials. These outcomes demonstrate that a lightweight AI model coupled with mobile manipulation can deliver reliable, shop-floor automation for low-volume, high-variation timber production. By shortening cycle times and lowering worker exposure to repetitive tasks, Woodot offers a viable pathway to enhance the environmental, economic, and social sustainability of digital timber construction. Nevertheless, some limitations remain, such as dependency on stable lighting conditions for optimal vision performance and the need for tool calibration checks. Full article
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23 pages, 750 KiB  
Systematic Review
Compliance and Adherence to Pelvic Floor Exercise Therapy in People with Pelvic Floor Disorders: A Systematic Review and Meta-Analysis
by Inmaculada Villa-Del-Pino, José-Jesús Jiménez-Rejano, Manuel Rebollo-Salas, Álvaro-José Rodríguez-Domínguez and Carmen-María Suárez-Serrano
Life 2025, 15(4), 613; https://doi.org/10.3390/life15040613 - 6 Apr 2025
Cited by 2 | Viewed by 2805
Abstract
Background: The impact of muscle-training treatment on quality of life and functional outcomes in people with pelvic floor dysfunction may be related to adherence rates. Methods: Nine electronic databases were searched for studies published up to 15 October 2024. A qualitative synthesis was [...] Read more.
Background: The impact of muscle-training treatment on quality of life and functional outcomes in people with pelvic floor dysfunction may be related to adherence rates. Methods: Nine electronic databases were searched for studies published up to 15 October 2024. A qualitative synthesis was used to describe the relationship between adherence or compliance with treatment, quality of life, and symptomatic severity. A meta-analysis of data from selected studies was performed that assessed quality of life and symptomatic severity in the short term. Results: Seven studies with 2190 participants were included. Of these studies, 42% showed rates greater than 80% in terms of adherence. A beneficial effect was found in terms of urinary incontinence severity without statistical differences between the groups (p = 0.813), while quality of life showed statistically significant improvements favoring the experimental group (p = 0.036). The quality of the evidence was collected or measured from low to high. Conclusions: People with pelvic floor disorders show high rates of adherence to pelvic floor muscle exercise and experience an improved quality of life in the short term, but more research is needed on the design of homogeneous systems to measure compliance and adherence to exercise-based treatments. Full article
(This article belongs to the Special Issue Innovative Perspectives in Physical Therapy and Health)
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31 pages, 4226 KiB  
Article
Raster Image-Based House-Type Recognition and Three-Dimensional Reconstruction Technology
by Jianbo Chang, Yunlei Lv, Jian Wang, Hao Pang and Yaqiu Liu
Buildings 2025, 15(7), 1178; https://doi.org/10.3390/buildings15071178 - 3 Apr 2025
Viewed by 740
Abstract
The automatic identification and three-dimensional reconstruction of house plans has emerged as a significant research direction in intelligent building and smart city applications. Three-dimensional models reconstructed from two-dimensional floor plans provide more intuitive visualization for building safety assessments and spatial suitability evaluations. To [...] Read more.
The automatic identification and three-dimensional reconstruction of house plans has emerged as a significant research direction in intelligent building and smart city applications. Three-dimensional models reconstructed from two-dimensional floor plans provide more intuitive visualization for building safety assessments and spatial suitability evaluations. To address the limitations of existing public datasets—including low quality, inaccurate annotations, and poor alignment with residential architecture characteristics—this study constructs a high-quality vector dataset of raster house plans. We collected and meticulously annotated over 5000 high-quality floor plans representative of urban housing typologies, covering the majority of common residential layouts in the region. For architectural element recognition, we propose a key point-based detection approach for walls, doors, windows, and scale indicators. To improve wall localization accuracy, we introduce CPN-Floor, a method that achieves precise key point detection of house plan primitives. By generating and filtering candidate primitives through axial alignment rules and geometric constraints, followed by post-processing to refine the positions of walls, doors, and windows, our approach achieves over 87% precision and 88% recall, with positional errors within 1% of the floor plan’s dimensions. Scale recognition combines YOLOv8 with Shi–Tomasi corner detection to identify measurement endpoints, while leveraging the pre-trained multimodal OFA-OCR model for digital character recognition. This integrated solution achieves scale calculation accuracy exceeding 95%. We design and implement a house model recognition and 3D reconstruction system based on the WebGL framework and use the front-end MVC design pattern to interact with the data and views of the house model. We also develop a high-performance house model recognition and reconstruction system to support the rendering of reconstructed walls, doors, and windows; user interaction with the reconstructed house model; and the history of the house model operations, such as forward and backward functions. Full article
(This article belongs to the Special Issue Information Technology in Building Construction Management)
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17 pages, 6209 KiB  
Article
Assessing Train-Induced Building Vibrations in a Subway Transfer Station and Potential Control Strategies
by Mengting Xing, Juxiang Zhu and Dingqing Chen
Buildings 2025, 15(7), 1024; https://doi.org/10.3390/buildings15071024 - 23 Mar 2025
Viewed by 482
Abstract
Transit-oriented development (TOD) and over-track buildings have been rapidly expanding in Chinese subways since their development. This new method is highly convenient for people while the influence of indoor vibration and noise in buildings is not yet clear. A case study is conducted [...] Read more.
Transit-oriented development (TOD) and over-track buildings have been rapidly expanding in Chinese subways since their development. This new method is highly convenient for people while the influence of indoor vibration and noise in buildings is not yet clear. A case study is conducted on over-track buildings on a subway transfer station in Chengdu, China. This paper first proposes a numerical prediction model based on a three-step approach to assess vibration impact. Then, a top-down comprehensive design of vibration mitigation based on the transmission path is developed to propose a practical control method. Furthermore, field measurements of vibrations on the ground and in nearby buildings are conducted. The results show that the over-track buildings are significantly affected by train operations, resulting in vertical vibrations with low frequencies ranging from 4 to 20 Hz. The vibration attenuation is different on different building floors, and the response frequency depends on the building’s natural frequency. The natural frequency of the main structures should differ from the main frequency of the vibration source to prevent high building vibration levels. Good comprehensive control strategies significantly reduce train-induced indoor secondary vibrations. Wider isolation trenches can significantly diminish the transfer of vibration transmission from the ground into the structure. These results can provide a guideline for developing transit-oriented buildings. Full article
(This article belongs to the Section Building Structures)
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22 pages, 795 KiB  
Review
Athletes’ Knowledge of Pelvic Floor Dysfunction and Their Knowledge of and Engagement with Pelvic Floor Muscle Training: A Scoping Review
by Jacinta Magor, Romany Martin and Marie-Louise Bird
Int. J. Environ. Res. Public Health 2025, 22(1), 104; https://doi.org/10.3390/ijerph22010104 - 14 Jan 2025
Viewed by 2112
Abstract
Introduction: Pelvic floor dysfunction (PFD) is prevalent among athletes. Investigating whether athletes are practicing pelvic floor muscle training (PFMT) will assist in delineating the factors underlying the burden of PFD in this population. Additionally, investigating athletes’ knowledge of PFD and knowledge of and [...] Read more.
Introduction: Pelvic floor dysfunction (PFD) is prevalent among athletes. Investigating whether athletes are practicing pelvic floor muscle training (PFMT) will assist in delineating the factors underlying the burden of PFD in this population. Additionally, investigating athletes’ knowledge of PFD and knowledge of and attitudes toward PFMT may inform interventions to improve the practice of PFMT. Aims: This scoping review aimed to collate the available evidence regarding athletes’ knowledge of PFD and their knowledge of and engagement with PFMT. Furthermore, this review aimed to determine the types of athletes (sports and competition levels) research had been conducted on and the definitions of PFD and PFMT most used. Methods: Six databases were searched up to January 2024. No study design or publication types were restricted; however, non-English articles were excluded due to resource constraints. Additional publications were identified through the reference lists of included articles. Data were synthesized and presented under subheadings relevant to the aims of this review. Results: Thirty-five publications were included for data extraction. Athletes had low practice of PFMT, poor knowledge of PFD and PFMT, but positive attitudes toward PFMT. One publication reported that higher levels of knowledge were associated with a lower prevalence of PFD. The athletic population was heterogeneous in sport type and competition level, and the definitions of PFD and PFMT were ill-defined. Conclusions: Athletes have a low practice of PFMT and poor knowledge of PFD and PFMT. The education of athletes may have a role in supporting pelvic floor health. Full article
(This article belongs to the Special Issue Physical Fitness and Injury Prevention in Athletes)
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23 pages, 20834 KiB  
Article
Inferring the Variability of Dielectric Constant on the Moon from Mini-RF S-Band Observations
by Shashwat Shukla, Gerald Wesley Patterson, Abhisek Maiti, Shashi Kumar and Nicholas Dutton
Remote Sens. 2024, 16(17), 3208; https://doi.org/10.3390/rs16173208 - 30 Aug 2024
Cited by 3 | Viewed by 1612
Abstract
The physical properties of lunar regolith are crucial for exploration planning, hazard assessment, and characterizing scientific targets at global and polar scales. The dielectric constant, a key property, offers insights into lunar material distribution within the regolith and serves as a proxy for [...] Read more.
The physical properties of lunar regolith are crucial for exploration planning, hazard assessment, and characterizing scientific targets at global and polar scales. The dielectric constant, a key property, offers insights into lunar material distribution within the regolith and serves as a proxy for identifying volatile-rich regoliths. Miniature radio frequency (Mini-RF) on the Lunar Reconnaissance Orbiter (LRO) provides a potential tool for mapping the lunar regolith’s physical nature and assessing the lunar volatile repository. This study presents global and polar S-band Mini-RF dielectric signatures of the Moon, obtained through a novel deep learning inversion model applied to Mini-RF mosaics. We achieved good agreement between training and testing of the model, yielding a coefficient of determination (R2 value) of 0.97 and a mean squared error of 0.27 for the dielectric constant. Significant variability in the dielectric constant is observed globally, with high-Ti mare basalts exhibiting lower values than low-Ti highland materials. However, discernibility between the South Pole–Aitken (SPA) basin and highlands is not evident. Despite similar dielectric constants on average, notable spatial variations exist within the south and north polar regions, influenced by crater ejecta, permanently shadowed regions, and crater floors. These dielectric differences are attributed to extensive mantling of lunar materials, impact cratering processes, and ilmenite content. Using the east- and west-looking polar mosaics, we estimated an uncertainty (standard deviation) of 1.01 in the real part and 0.03 in the imaginary part of the dielectric constant due to look direction. Additionally, modeling highlights radar backscatter sensitivity to incidence angle and dielectric constant at the Mini-RF wavelength. The dielectric constant maps provide a new and unique perspective of lunar terrains that could play an important role in characterizing lunar resources in future targeted human and robotic exploration of the Moon. Full article
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22 pages, 47765 KiB  
Article
Pix2Pix-Assisted Beijing Hutong Renovation Optimization Method: An Application to the UTCI and Thermal and Ventilation Performance
by Rui Wu, Ming Huang, Zhenqing Yang, Lili Zhang, Lei Wang, Wei Huang and Yongqiang Zhu
Buildings 2024, 14(7), 1957; https://doi.org/10.3390/buildings14071957 - 27 Jun 2024
Cited by 4 | Viewed by 1685
Abstract
In response to the issues of low outdoor thermal comfort and poor ventilation environment in Beijing Hutong, this paper proposes a rapid intelligent optimization method combining Pix2Pix (Image-to-Image Translation with Conditional Adversarial Networks) with a genetic algorithm. Firstly, the architectural types of the [...] Read more.
In response to the issues of low outdoor thermal comfort and poor ventilation environment in Beijing Hutong, this paper proposes a rapid intelligent optimization method combining Pix2Pix (Image-to-Image Translation with Conditional Adversarial Networks) with a genetic algorithm. Firstly, the architectural types of the research objects are highly refined and summarized into four traditional building types. Then, they are placed in the site with open spaces in a certain proportion, and a multi-objective optimization model for the UTCI (Universal Thermal Climate Index) and building area is constructed using a genetic algorithm, generating and iteratively optimizing the spatial layout of the building population. Finally, Pix2Pix is used to learn and train a large number of Hutong combination samples, rapidly generating the UTCI and ventilation results, which serve as the optimization objectives to obtain the optimal solution set for Hutong spatial forms. Compared with traditional empirical design methods, this method allows for a rapid and efficient traversal of vast solution spaces, intelligently generating Hutong renovation schemes that balance cultural heritage and healthy comfort. The research results demonstrate that this method can quickly find (26.4 times faster than traditional performance simulation methods) that the reasonable proportions of Siheyuan, Sanheyuan, Erheyuan, new buildings, and empty spaces in the Da Yuan Hutong in Beijing should be controlled at 11.8%, 16.9%, 23.8%, 33.8%, and 13.7%, respectively. Meanwhile, the building density should be maintained between 0.5 and 0.58, and the floor area ratio should be kept between 0.96 and 1.14. This significantly improves outdoor comfort, enhances the living environment of the Hutong, and promotes sustainable urban development. Full article
(This article belongs to the Section Architectural Design, Urban Science, and Real Estate)
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13 pages, 456 KiB  
Article
Robust Detection of Background Acoustic Scene in the Presence of Foreground Speech
by Siyuan Song, Yanjue Song and Nilesh Madhu
Appl. Sci. 2024, 14(2), 609; https://doi.org/10.3390/app14020609 - 10 Jan 2024
Cited by 1 | Viewed by 1263
Abstract
The characterising sound required for the Acoustic Scene Classification (ASC) system is contained in the ambient signal. However, in practice, this is often distorted by e.g., foreground speech of the speakers in the surroundings. Previously, based on the iVector framework, we proposed different [...] Read more.
The characterising sound required for the Acoustic Scene Classification (ASC) system is contained in the ambient signal. However, in practice, this is often distorted by e.g., foreground speech of the speakers in the surroundings. Previously, based on the iVector framework, we proposed different strategies to improve the classification accuracy when foreground speech is present. In this paper, we extend these methods to deep-learning (DL)-based ASC systems, for improving foreground speech robustness. ResNet models are proposed as the baseline, in combination with multi-condition training at different signal-to-background ratios (SBRs). For further robustness, we first investigate the noise-floor-based Mel-FilterBank Energies (NF-MFBE) as the input feature of the ResNet model. Next, speech presence information is incorporated within the ASC framework obtained from a speech enhancement (SE) system. As the speech presence information is time-frequency specific, it allows the network to learn to distinguish better between background signal regions and foreground speech. While the proposed modifications improve the performance of ASC systems when foreground speech is dominant, in scenarios with low-level or absent foreground speech, performance is slightly worse. Therefore, as a last consideration, ensemble methods are introduced, to integrate classification scores from different models in a weighted manner. The experimental study systematically validates the contribution of each proposed modification and, for the final system, it is shown that with the proposed input features and meta-learner, the classification accuracy is improved in all tested SBRs. Especially for SBRs of 20 dB, absolute improvements of up to 9% can be obtained. Full article
(This article belongs to the Special Issue Deep Learning Based Speech Enhancement Technology)
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19 pages, 4699 KiB  
Technical Note
Sexual Disability in Low Back Pain: Diagnostic and Therapeutic Framework for Physical Therapists
by Carla Vanti, Silvano Ferrari, Marco Chiodini, Cesare Olivoni, Arianna Bortolami and Paolo Pillastrini
Healthcare 2024, 12(1), 80; https://doi.org/10.3390/healthcare12010080 - 29 Dec 2023
Cited by 2 | Viewed by 5449
Abstract
Background: The literature shows a relationship between sexual activity and low back pain (LBP). The aim of this work is to provide a theoretical framework and practical proposal for the management of sexual disability in individuals with LBP. Methods: Based on a literature [...] Read more.
Background: The literature shows a relationship between sexual activity and low back pain (LBP). The aim of this work is to provide a theoretical framework and practical proposal for the management of sexual disability in individuals with LBP. Methods: Based on a literature review, a team of specialized physical therapists developed a pattern for the management of LBP-related sexual disability. Results: A patient reporting LBP-related sexual disability may be included in one of four clinical decision-making pathways corresponding to one of the following: #1 standard physical therapy (PT); #2 psychologically informed physical therapy (PIPT); #3 PIPT with referral; or #4 immediate referral. Standard PT concerns the management of LBP-related sexual disability in the absence of psychosocial or pathological issues. It includes strategies for pain modulation, stiffness management, motor control, stabilization, functional training, pacing activities comprising education, and stay-active advice. PIPT refers to patients with yellow flags or concerns about their relationship with partners; this treatment is oriented towards a specific psychological approach. “PIPT with referral” and “Immediate referral” pathways concern patients needing to be referred to specialists in other fields due to relationship problems or conditions requiring medical management or pelvic floor or sexual rehabilitation. Conclusions: The proposed framework can help clinicians properly manage patients with LBP-related sexual disability. Full article
(This article belongs to the Special Issue Outcome Measures and Innovative Approaches in Rehabilitation)
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10 pages, 1571 KiB  
Article
Is Diastasis Recti Abdominis Rehabilitation after Childbirth Able to Prevent the Onset of Stress Urinary Incontinence? A Case-Control Study
by Andrea Braga, Livia Galli, Giorgio Caccia, Giulia Amato, Andrea Papadia, Marco Torella, Stefano Salvatore, Chiara Scancarello, Yoav Baruch and Maurizio Serati
Medicina 2023, 59(12), 2182; https://doi.org/10.3390/medicina59122182 - 15 Dec 2023
Cited by 1 | Viewed by 3197
Abstract
Background and Objectives: Pelvic floor muscle training (PFMT) represent the first-line approach to pelvic floor dysfunctions (PFDs). Recently, studies have shown a synergy between the pelvic floor and abdominal muscles, hypothesizing that the anatomical and functional integrity of the abdominal wall plays a [...] Read more.
Background and Objectives: Pelvic floor muscle training (PFMT) represent the first-line approach to pelvic floor dysfunctions (PFDs). Recently, studies have shown a synergy between the pelvic floor and abdominal muscles, hypothesizing that the anatomical and functional integrity of the abdominal wall plays a role in the prevention of pelvic floor disorders. Some studies have shown a significant correlation between diastasis recti abdominis (DRA) and stress urinary incontinence (SUI). Nevertheless, the evidence reported in the literature is controversial and based on low-quality data. The aim of the study is to clarify whether DRA-specific abdominal rehabilitation is needed in women with SUI after childbirth. Materials and Methods: All consecutive women who had at least one delivery and complained of symptoms of pure SUI that were urodynamically proven were considered for the study. The group of symptomatic patients was compared with a series of consecutive women, identified during the same study period, without any symptoms of SUI. In both groups, we measured the inter-rectal distance (IRD) with an ultrasound scanner above and below the navel. Results: A total of 102 women eligible for the study group and 100 women who did not report any symptoms of SUI were enrolled. The inter-rectal distance above the umbilicus showed no significant difference between the two groups (2.12 ± 0.98 vs. 2.1 ± 0.77; p = 0.94). In contrast, the data from the sub-umbilical measurements showed a significant difference. Surprisingly, the asymptomatic group showed significantly greater (0.98 ± 0.9 vs. 1.33 ± 0.87 p-value: 0.009) IRD compared to the symptomatic group. Conclusions: The study shows that DRA is not a risk factor for SUI in women after childbirth. Therefore, specific abdominal wall rehabilitation after childbirth does not seem to be indicated. Full article
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34 pages, 21809 KiB  
Article
Auxiliary Power Supply System with Parallel-Connected DC–AC Inverters for Low-Floor Light Rail Vehicle
by Paiwan Kerdtuad, Kunjana Chaiamarit and Supat Kittiratsatcha
Electronics 2023, 12(14), 3117; https://doi.org/10.3390/electronics12143117 - 18 Jul 2023
Cited by 1 | Viewed by 5342
Abstract
This research proposes a roof-mounted auxiliary power supply (APS) system for 600 VDC low-floor light rail vehicles (LRVs). The proposed APS system consists of five parallel-connected dc–ac inverter modules (modules 1–5). Inverter modules 1 and 2 are three-phase dc–ac inverters for the compressor [...] Read more.
This research proposes a roof-mounted auxiliary power supply (APS) system for 600 VDC low-floor light rail vehicles (LRVs). The proposed APS system consists of five parallel-connected dc–ac inverter modules (modules 1–5). Inverter modules 1 and 2 are three-phase dc–ac inverters for the compressor motors of the air conditioning system, and inverter modules 3 and 4 are three-phase dc–ac inverters for the air pump motors of the air supply system. Inverter module 5 is a single-phase dc–ac inverter for the 220 VAC power supply of onboard electric loads. Simulations and experiments were carried out under variable load torques and output frequencies for modules 1–4 and under full and no resistive loads for module 5. The measured total input current and total input power of the proposed APS system under the full-load condition are 114.36 A and 68.84 kW. The total efficiency of the proposed APS system (modules 1–5) is 97.05%. The proposed APS system is suitable for 600 VDC low-floor LRVs. The novelty of this research lies in the use of five parallel-connected inverter modules, as opposed to the three-phase output transformer or isolated dc–dc converter in the early and conventional APS systems. Specifically, the proposed APS system requires neither a three-phase output transformer nor an isolated dc–dc converter. Full article
(This article belongs to the Section Power Electronics)
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17 pages, 1125 KiB  
Article
Investigations on the Optimal Estimation of Speech Envelopes for the Two-Stage Speech Enhancement
by Yanjue Song and Nilesh Madhu
Sensors 2023, 23(14), 6438; https://doi.org/10.3390/s23146438 - 16 Jul 2023
Cited by 2 | Viewed by 1738
Abstract
Using the source-filter model of speech production, clean speech signals can be decomposed into an excitation component and an envelope component that is related to the phoneme being uttered. Therefore, restoring the envelope of degraded speech during speech enhancement can improve the intelligibility [...] Read more.
Using the source-filter model of speech production, clean speech signals can be decomposed into an excitation component and an envelope component that is related to the phoneme being uttered. Therefore, restoring the envelope of degraded speech during speech enhancement can improve the intelligibility and quality of output. As the number of phonemes in spoken speech is limited, they can be adequately represented by a correspondingly limited number of envelopes. This can be exploited to improve the estimation of speech envelopes from a degraded signal in a data-driven manner. The improved envelopes are then used in a second stage to refine the final speech estimate. Envelopes are typically derived from the linear prediction coefficients (LPCs) or from the cepstral coefficients (CCs). The improved envelope is obtained either by mapping the degraded envelope onto pre-trained codebooks (classification approach) or by directly estimating it from the degraded envelope (regression approach). In this work, we first investigate the optimal features for envelope representation and codebook generation by a series of oracle tests. We demonstrate that CCs provide better envelope representation compared to using the LPCs. Further, we demonstrate that a unified speech codebook is advantageous compared to the typical codebook that manually splits speech and silence as separate entries. Next, we investigate low-complexity neural network architectures to map degraded envelopes to the optimal codebook entry in practical systems. We confirm that simple recurrent neural networks yield good performance with a low complexity and number of parameters. We also demonstrate that with a careful choice of the feature and architecture, a regression approach can further improve the performance at a lower computational cost. However, as also seen from the oracle tests, the benefit of the two-stage framework is now chiefly limited by the statistical noise floor estimate, leading to only a limited improvement in extremely adverse conditions. This highlights the need for further research on joint estimation of speech and noise for optimum enhancement. Full article
(This article belongs to the Special Issue Machine Learning and Signal Processing Based Acoustic Sensors)
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13 pages, 18410 KiB  
Article
Effect of the Laying Order of Core Layer Materials on the Sound-Insulation Performance of High-Speed Train Carbody
by Ruiqian Wang, Dan Yao, Jie Zhang, Xinbiao Xiao and Xuesong Jin
Materials 2023, 16(10), 3862; https://doi.org/10.3390/ma16103862 - 20 May 2023
Cited by 6 | Viewed by 2265
Abstract
The design of sound-insulation schemes requires the development of new materials and structures while also paying attention to their laying order. If the sound-insulation performance of the whole structure can be improved by simply changing the laying order of materials or structures, it [...] Read more.
The design of sound-insulation schemes requires the development of new materials and structures while also paying attention to their laying order. If the sound-insulation performance of the whole structure can be improved by simply changing the laying order of materials or structures, it will bring great advantages to the implementation of the scheme and cost control. This paper studies this problem. First, taking a simple sandwich composite plate as an example, a sound-insulation prediction model for composite structures was established. The influence of different material laying schemes on the overall sound-insulation characteristics was calculated and analyzed. Then, sound-insulation tests were conducted on different samples in the acoustic laboratory. The accuracy of the simulation model was verified through a comparative analysis of experimental results. Finally, based on the sound-insulation influence law of the sandwich panel core layer materials obtained from simulation analysis, the sound-insulation optimization design of the composite floor of a high-speed train was carried out. The results show that when the sound absorption material is concentrated in the middle, and the sound-insulation material is sandwiched from both sides of the laying scheme, it represents a better effect on medium-frequency sound-insulation performance. When this method is applied to the sound-insulation optimization of a high-speed train carbody, the sound-insulation performance of the middle and low-frequency band of 125–315 Hz can be improved by 1–3 dB, and the overall weighted sound reduction index can be improved by 0.9 dB without changing the type, thickness or weight of the core layer materials. Full article
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18 pages, 12059 KiB  
Article
Indirect Assessment of Railway Infrastructure Anomalies Based on Passenger Comfort Criteria
by Patricia Silva, Diogo Ribeiro, Pedro Pratas, Joaquim Mendes and Eurico Seabra
Appl. Sci. 2023, 13(10), 6150; https://doi.org/10.3390/app13106150 - 17 May 2023
Cited by 3 | Viewed by 2183
Abstract
Railways are among the most efficient and widely used mass transportation systems for mid-range distances. To enhance the attractiveness of this type of transport, it is necessary to improve the level of comfort, which is much influenced by the vibration derived from the [...] Read more.
Railways are among the most efficient and widely used mass transportation systems for mid-range distances. To enhance the attractiveness of this type of transport, it is necessary to improve the level of comfort, which is much influenced by the vibration derived from the train motion and wheel-track interaction; thus, railway track infrastructure conditions and maintenance are a major concern. Based on discomfort levels, a methodology capable of detecting railway track infrastructure failures is proposed. During regular passenger service, acceleration and GPS measurements were taken on Alfa Pendular and Intercity trains between Porto (Campanhã) and Lisbon (Oriente) stations. ISO 2631 methodology was used to calculate instantaneous floor discomfort levels. By matching the results for both trains, using GPS coordinates, 12 track section locations were found to require preventive maintenance actions. The methodology was validated by comparing these results with those obtained by the EM 120 track inspection vehicle, for which similar locations were found. The developed system is a complementary condition-based maintenance tool that presents the advantage of being low-cost while not disturbing regular train operations. Full article
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