Search Results (1,087)

In Optical Camera Communication (OCC), precise localization of LED arrays under complex tilt conditions is a core challenge for reliable decoding. This paper proposes an OCC reception scheme for RGB-LED arrays that integrates YOLO-OBB rotated object detection with two-stage geometric correction. The system first employs a YOLOv8n-OBB model to extract a quadrilateral region of interest that tightly encloses the LED array boundary. This effectively suppresses background interference caused by superimposed perspective tilt and in-plane rotation. A coarse-to-fine two-stage correction framework is then applied. The first stage rapidly eliminates the dominant perspective distortion based on the detected bounding-box corners. The second stage performs a refined correction using the actual LED center positions. Two homography matrices are cascaded into a combined transformation, achieving two-stage correction accuracy through a single coordinate mapping. In the corrected image, K-Means clustering constructs a 16 × 16 LED topological grid. A locking strategy is adopted so that subsequent frames skip repeated LED detection and clustering. The steady-state per-frame processing time is reduced to approximately 78.9 ms. Experiments covered 16 cross-combinations of vertical tilt from 0° to 45° (0°, 15°, 30°, 45°) and in-plane rotation from 0° to 40° (0°, 15°, 30°, 40°). The uncorrected scheme and the horizontal-box scheme experienced severe bit errors or complete failure under complicated distortion. The proposed scheme maintained error-free transmission under all 16 tested conditions. The ratios of opposite sides of the corrected LED grid remained stable between 0.997 and 1.004. The system simultaneously achieves high reliability and low-latency real-time processing under complex geometric distortions. Full article

This study aimed to design, develop, and evaluate a multi-axis welding positioner, designed as a laboratory simulator with 360° rotational capability and 90° tilting functionality to support outcome-based instruction in welding and fabrication technology courses. A developmental research design was employed to systematically address common challenges in instructional welding operations, such as limited workpiece maneuverability, inconsistent welding angles, operator fatigue, safety risks from manual repositioning, and the lack of affordable, adaptable positioning equipment. The study was conducted at Caraga State University–Cabadbaran Campus in Cabadbaran City, Agusan del Norte, and involved sixteen purposively selected experts in Welding and Fabrication Technology. These experts assessed the prototype during the design, development, and evaluation phases via a validated researcher-developed survey instrument. The welding positioner was evaluated based on the following criteria: design, construction and material availability, functionality, usability, safety, modularity, and ergonomics. Data were analyzed using descriptive statistics. Findings indicated that the prototype was highly functional, safe, and user-centered, enhancing welding accuracy and reducing operator fatigue. Of the evaluated parameters, Design, Construction, and Material Availability achieved the highest mean rating (3.61), reflecting strong structural quality and resource accessibility. Functionality received the lowest mean rating (3.51), signaling minor areas for improvement in responsiveness and component adjustability. The prototype, built from locally available, cost-effective materials, featured a motorized rotation system and a manual tilting mechanism that operated reliably during testing. The study concluded that the welding positioner met structural, ergonomic, and operational standards for use as a laboratory simulator in outcome-based welding instruction. Recommendations include integrating automated controls, enhancing portability, embedding digital monitoring features, and conducting extended performance evaluations in industrial settings. Full article

With the advancement of artificial intelligence (AI) technologies such as large language models and autonomous driving, the data traffic via optical interconnects in data centers has surged significantly. The stability of the optical interconnects relies on intelligent operation and maintenance (O&M). Integrated sensing and communication (ISAC) over fibers enables vibration sensing utilizing existing communication fibers, providing critical support for intelligent O&M in data centers. Compared to sensing in the coherent systems, it is difficult to use phase and state of polarization (SOP) monitoring for vibration detection in intensity-modulation and direct-detection (IM-DD) systems. In this paper, we propose a joint phase-based and SOP-based sensing scheme integrated in IM-DD systems. In the proposed scheme, the received IM-DD communication signals are tapped for sensing with a power ratio of 10%. Then the tapped signals are split for vibration sensing based on SOP and phase, respectively. In the phase-based sensing arm, a circulator, a $3\times 3$ coupler and two Faraday rotating mirrors (FRMs) are used to build an unbalanced Michelson interferometer without phase fading and polarization fading. For the purpose of SOP-based sensing, a polarizer is used to monitor the vibration-induced SOP variations. Experimental results demonstrate that the proposed scheme enables vibration sensing based on both phase and SOP across a frequency range of 200 Hz to 10 kHz. Regarding the communication performance, the integration of the sensing system only induces 0.8 dB received optical power penalty. This vibration-sensing scheme based on both phase and SOP can be integrated into pluggable optical modules, providing an efficient and reliable solution for intelligent optical network O&M. Full article

This research introduces a unique optimization framework centered on the Geese V-Formation Algorithm to enhance the technical planning of distributed energy resources in renewable microgrid-oriented radial distribution systems. The proposed methodology addresses the optimal placement and sizing of photovoltaic panels, wind turbines, battery energy storage systems, and capacitor banks to provide comprehensive voltage support, minimize active power losses, and refine overall grid functionality. Drawing inspiration from the aerodynamic efficiency of migratory geese, the Geese V-Formation Algorithm integrates dynamic leader-follower coordination, adaptive role rotation, and cooperative information exchange mechanisms. These features allow the algorithm to effectively balance global exploration and local exploitation, making it uniquely suited to address the complex, nonlinear, and multi-objective nature of modern microgrid design. The effectiveness of this approach was evaluated through rigorous simulations on the IEEE-33 and IEEE-69 bus distribution systems utilizing the Python programming language. The empirical results indicate that the Geese V-Formation Algorithm achieves substantial power loss reductions, reaching 91.62% and 92.45%, respectively, when integrating solar and wind resources with energy storage and reactive power compensation. Furthermore, the optimized configurations significantly improved bus voltage profiles and enhanced substation power factors, confirming the technical effectiveness of the framework under the considered benchmark constraints. By providing a technical decision-support approach for engineers and utility planners, this framework facilitates the deployment of reliable, decentralized renewable energy systems that align with global energy transition objectives and promote sustainable infrastructure development. Full article

Background: High-level badminton performance requires rapid perceptual processing, visuomotor coordination, and precise movement responses under continuously changing spatial conditions. Although wearable sports vision interventions have shown potential for enhancing perceptual–motor performance, evidence regarding their longitudinal effects and transfer to sport-specific outcomes remains limited. Trial design: A single-center, exploratory randomized controlled trial using a parallel-group structure. Simple randomization without blocking or stratification resulted in a final allocation ratio of 16:10 (approximately 1.6:1) between the training and control groups. Methods: Twenty-six collegiate badminton athletes aged 18–25 were randomized into a wearable sports vision training group (n = 16) or a control group (n = 10). The intervention group completed wearable sports vision training using Automatic Dual Rotational Risley Prisms (ADRRPs) for 15 min twice weekly over 4 weeks. Results: Baseline-adjusted ANCOVA demonstrated significant between-group effects for reaction time (p = 0.003) and target-zone accurate hits (p = 0.004), whereas binocular visual function outcomes did not show statistically significant between-group differences. No adverse events were reported. Conclusions: Four weeks of wearable sports vision training may be associated with improvements in selected visuomotor outcomes, particularly reaction performance and target-zone hitting accuracy, in collegiate badminton players. Larger trials are needed to evaluate long-term retention and broader sport-specific applicability. Trial registration: ClinicalTrials.gov Identifier: NCT07105462, registered 29 July 2025. Full article

The increasing use of cardiac implantable electronic devices (CIEDs) in pediatric and adolescent populations has led to a growing need for transvenous lead extraction (TLE). However, data on long-term outcomes remain limited. This study aimed to evaluate the efficacy and safety of TLE using mechanical rotational dilator sheaths in a pediatric cohort. This retrospective single-center study included 35 patients who underwent TLE between 2007 and 2025. Outcomes were compared between Evolution^® (Cook Medical, Bloomington, IN, USA) and TightRail™ (Spectranetics/Philips, Colorado Springs, CO, USA) sheath systems. A total of 40 leads were extracted (mean age at extraction: 15.1 ± 4.2 years; 57% male). The most common indication for extraction was lead fracture/dysfunction (22/35–63%). Complete success with the procedure was achieved in 23 (66%) patients, and clinical success in 30 (86%). Major complications requiring surgery occurred in 5 (14%) patients, and minor complications in 2 (6%). Notably, all major complications occurred in patients with implantable cardioverter-defibrillator (ICD) leads (p = 0.013), including innominate vein injury, pericardial effusion, tricuspid entrapment, and cardiac perforation. A comparison of the Evolution^® (n:20) and TightRail™ (n:15) sheath groups showed no statistically significant differences in complete procedural success (p = 0.603), clinical success (p = 0.604), or the incidence of major complications (p = 0.640). No procedure-related mortality was observed. TLE using mechanical rotational dilator sheaths in pediatric patients is feasible and provides acceptable clinical success rates. However, the risk of major complications remains considerable, particularly in patients with ICD leads. These findings highlight the importance of careful procedural planning and performing TLE in experienced centers with immediate surgical backup. Full article

Background/Objectives: Due to the inherent rotational instability of the proximal fragment in unstable basicervical intertrochanteric (IT) fractures, the biomechanical effect of lag screw position may differ from that observed in typical unstable IT fractures. This study aimed to evaluate the influence of lag screw positioning on proximal fragment displacement and stress distribution after cephalomedullary nailing (CMN) in unstable basicervical IT fractures using finite element analysis. Methods: Twelve finite element models of unstable basicervical IT fractures fixed with a CM nail were constructed with lag screws placed in four anteroposterior (AP) positions (superior 5 mm, center, inferior 5 mm, and inferior 10 mm) and three axial positions (anterior, center, and posterior). The positional change of the proximal fragment and stress concentration on the nail construct were measured. Results: In this computational model, proximal fragment displacement and stress concentration, including peak von Mises stress and mean stress over a region of interest, increased as the lag screw was positioned more inferiorly on the AP view and more posteriorly on the axial view. Conversely, a relatively superior-anterior lag screw position was associated with the lowest proximal fragment displacement and reduced stress concentration on the nail construct and around the lag screw tip. Conclusions: Within the limitations of this finite element analysis using a single femoral model and axial loading condition, a relatively superior-anterior lag screw position was associated with more favorable biomechanical behavior compared with more inferior or posterior positions. These findings should be interpreted as hypothesis-generating biomechanical observations rather than direct clinical guidance. Full article

Wearable inertial sensors offer a portable alternative to laboratory-grade force plates for postural stability assessment; however, their validity across progressively challenging balance tasks remains under-explored. This study evaluated the reliability and concurrent validity of inertially sensed metrics compared with force-plate-derived postural sway metrics across a five-level spectrum of unstable surfaces (Floor, Foam Pad, Rotating Disc, Air Disc, Bosu). Twenty-five healthy young women (22.1 ± 3.6 years, 1.64 ± 0.04 m, 58.44 ± 8.21 kg) performed five trials of single-leg standing (40 s each) on each surface. Postural sway was computed from antero-posterior (AP) and medio-lateral (ML) center of pressure (CoP) recordings using a force plate (Kistler, 9286 AA, Winterthur, Switzerland, sampling at 500 Hz) in synchronization with a lateral shank-mounted inertial sensor (Bionomadix BN-ACCL3, Biopac Systems, Inc., Santa Barbara, CA, USA, sampling at 100 Hz). In addition to reliability, a two-tiered analysis evaluated global concordance (unstandardized slopes) and method agreement (standardized z-scores). Intraclass correlation coefficients (ICCs) for the inertial sensor were excellent (range: 0.95–0.96), surpassing the force plate (range: 0.85–0.92) as trials accumulated. Analysis revealed moderate-to-good global concordance in the AP direction (r = 0.60, p = 0.001) and good-to-excellent in the ML one (r = 0.85, p < 0.001), validating the progressive intensifying effect of the surface graduation. Individual ranking agreement—evaluated via standardized z-scores—was also significant in both the AP (r = 0.61, p < 0.001) and the ML (r = 0.85, p < 0.001) directions, indicating a convergence into how the two modalities rank individual performance. Bland–Altman plots confirmed high absolute agreement between standardized scores, though a predictable proportional bias was observed in raw units, where the inertial sensor’s underestimation of sway magnitude increased linearly with task difficulty. The five-level postural challenge graduation is a highly reliable framework for balance assessment. While the shank-mounted sensor exhibits proportional underestimation of sway magnitude compared to the CoP at extreme intensities, its high internal stability and sensitivity to task difficulty make it a valid and robust tool for longitudinal clinical monitoring. Full article

Rolling bearing fault diagnosis is critical for ensuring the safe operation of rotating machinery, yet it faces significant challenges in noisy environments. This paper proposes BEAM-Net (Bearing-spectrum Enhanced by EMA and Weighted Spectral Convolution Network), a lightweight neural network designed specifically for rolling bearing fault diagnosis under strong noise conditions. Classifying bearing faults from vibration signals remains a challenging task when fault-related features are subtle and easily submerged in background noise—especially when the signal-to-noise ratio (SNR) is low. To address this challenge, BEAM-Net adopts a “decompose–enhance–extract” pipeline: first, an Exponential-Moving-Average Trend Decomposer (ETD) splits the frequency spectrum into a smooth trend component and a fault-sensitive residual component; second, a Spectral Residual Gate (SRG) reinjects detailed residual information through a learnable gating mechanism; finally, a Weighted Spectrum Convolution block (WSC) incorporates a symmetric center-emphasizing prior into the convolution kernel, ensuring that local spectral patterns receive greater attention. Experimental results on the Case Western Reserve University (CWRU) bearing dataset at SNR = −6 dB show that BEAM-Net achieves an F1 score of 99.15% with only 2835 parameters. Compared to the single-convolution baseline, this represents a $+0.78\%$ improvement in F1 score and a 50% reduction in the false positive rate (from $0.18\%$ to $0.09\%$). Cross-dataset validation on the Paderborn University (PU) and Machinery Failure Prevention Technology (MFPT) datasets further confirms the generalizability of the proposed approach, achieving F1 scores of 97.83% and 98.46%, respectively, under comparable noise conditions. These findings demonstrate that combining explicit spectral trend modeling with weighted convolution is not only effective but also parameter-efficient, making it well-suited for noise-robust rolling bearing fault diagnosis. It should be noted that the current method is primarily validated on spectral-analysis-based diagnostics of rolling bearings; its applicability to other vibroacoustic diagnostic modalities (e.g., tapping or nonlinear vibration excitation) and to quantitative defect severity grading remains to be investigated in future work. Full article

Background/Objectives: Egocentric and allocentric spatial transformations are central to spatial cognition, yet it is unknown whether they rely on the same neural mechanisms. The goal of this study was to examine whether egocentric transformations engage the neural processes associated with mental rotation in visual–spatial working memory. Methods: High-density EEG was recorded while participants performed two matched pointing-direction tasks, in which they indicated the direction toward a target location, while instructed to use either allocentric array rotation or egocentric perspective-taking. Response times and accuracy were recorded, and event-related potential (ERP) responses were analyzed as a function of rotation angle (100° vs. 160°) and differences between front and back pointing directions. Results: Response times increased with rotation angle in both tasks, whereas a front–back asymmetry in accuracy was observed only in perspective-taking. Both tasks showed rotation-related ERP modulation, but the timing and spatial distribution of these effects differed across tasks. In the array-rotation task, rotation-related ERP effects were observed over right-parieto–occipital regions at 460–510 ms. In the perspective-taking task, the ERP effects were observed over left-central regions at 400–470 ms and 520–610 ms. ERP differences between front and back directions were robust and widespread in the egocentric condition but limited in the allocentric condition. Conclusions: Perspective-taking does not show the posterior rotation-related ERP effect associated with mental rotation of object representations in visual–spatial working memory. Instead, it appears to reflect updating of the observer-centered reference frame, consistent with simulated self-motion processes involving vestibular and proprioceptive signals. Full article

Efficient capture of respirable dust remains difficult in fully mechanized excavation roadways because fine particles readily migrate with airflow beyond the effective spray region. Here, a wind-assisted negative-pressure dust suppression device was developed by integrating annular Venturi entrainment with a mechanical air duct, enabling coupled airflow induction and droplet transport. The device was optimized using nozzle atomization tests, CFD-based orthogonal simulations, and laboratory-scale validation. The results show that an SK508 solid-cone nozzle provides suitable atomization for Venturi-induced suction. Using induced air inlet velocity and diffuser-inlet static pressure as evaluation indicators, the optimal Venturi unit was obtained at 0.1 MPa water pressure, 0.4 MPa air pressure, a 15° diffuser angle, and a throat-center nozzle position. For the integrated device, the best configuration was ten Venturi tubes, an impeller rotational speed of 2400 r/min, and an impeller position of 300 mm from the air duct inlet. In laboratory-scale tests, the complete wind-assisted negative-pressure mode outperformed fan-only, spray-only, wind-assisted spray, and negative-pressure secondary dust suppression modes, achieving maximum total and respirable dust suppression efficiencies of 87.39% and 86.68%. The results demonstrate the feasibility of coupling mechanical airflow with Venturi entrainment and support subsequent field-scale validation. Full article

Background/Objectives: Paprosky Type IIC acetabular defects encountered during revision total hip arthroplasty (rTHA) present substantial challenges in terms of surgical planning and implant stability. This study evaluates the outcomes of indication-based reconstruction strategies using dual mobility cups (DMC) and reconstruction cages (RC) in patients with Paprosky Type IIC acetabular defects. Methods: This retrospective, non-randomized study included 41 patients who underwent revision total hip arthroplasty for Paprosky Type IIC acetabular defects between 2014 and 2023, reflecting an indication-based treatment strategy. Patients were categorized into two groups: the DMC group (n = 25) and the RC group (n = 16). Clinical evaluation was performed using the Harris Hip Score (HHS), while radiographic assessment focused on the restoration of the hip center of rotation. Complications, revision rates, and implant survivorship were also analyzed. Results: Both groups demonstrated significant functional improvement; however, the differences in postoperative HHS were observed between groups (86.1 vs. 74.7; p < 0.001). The DMC group also showed a shorter operative time, reduced blood loss, and a shorter hospital stay (p < 0.05). Although the dislocation rate was lower in the DMC group (4% vs. 12.5%), the difference was not statistically significant. The overall complication rate was markedly higher in the RC group (68.8% vs. 28.0%; p = 0.010). Implant survivorship was high in both groups (92.7%), with no significant difference between them. Mean follow-up duration was 49.9 ± 16.0 months. Conclusions: Both dual mobility cups and reconstruction cages can achieve successful outcomes in revision total hip arthroplasty for Paprosky Type IIC acetabular defects. However, the observed differences in perioperative and functional outcomes should be interpreted within the context of indication-based patient selection and do not imply superiority of one reconstruction strategy over the other. Rather, these findings reflect outcomes of reconstruction strategies applied according to defect reconstructability in a real-world clinical setting. Full article

During the hoisting of prefabricated segmented beams, the alignment of rods and holes mainly relies on manual operation, which suffers from low safety and efficiency. To improve the safety and efficiency of rod–hole alignment, this paper proposes a vision-based alignment method for hoisting prefabricated segmented beams. The method uses binocular vision to measure the spatial coordinates of key points on rods and holes, establishes a mathematical model for alignment, and calculates the center distance and relative rotation angle between them. An experimental platform is built and tests are conducted. The results show that the proposed method can effectively measure the center distance and rotation angle, improve measurement efficiency and safety, achieve high accuracy, and possess high practical engineering value. Full article

To address the demanding requirements for high gain, wide bandwidth, and stable circularly polarized (CP) radiation in wireless local area network (WLAN) applications, this paper proposes and implements a broadband circularly polarized array antenna primarily targeting the 2.4–2.484 GHz ISM band. The design employs a coplanar waveguide fed broadband CP monopole antenna as the radiating element. A sequential rotation technique is utilized to form a four-element array, and a windmill-shaped defected ground structure is introduced to further extend the bandwidth. The antenna is fabricated on a low-cost FR4 substrate with overall dimensions of 0.98λ₀ × 0.98λ₀ × 0.008λ₀ at 2.4 GHz. Simulation and measurement results show that the array antenna achieves a −10 dB impedance bandwidth of 1.22–2.78 GHz (87.1% relative bandwidth) and a 3-dB axial ratio bandwidth of 1.85–2.66 GHz (35.0% relative bandwidth), ensuring sufficient margin over the target WLAN band. At the center frequency of 2.45 GHz, the antenna exhibits left-hand circular polarization radiation, with a measured peak gain of 8.2 dBic and a cross-polarization discrimination better than 20 dB. To verify its performance advantages in practical systems, the designed antenna was integrated into a ZigBee wireless communication system for data transmission testing. Under controlled conditions, the system employing the proposed antenna achieves a packet loss rate of 3.0% ± 0.4% in a complex multipath environment, significantly outperforming a traditional linear-polarized whip antenna (19.0% ± 1.1%). The results demonstrate that the proposed antenna, featuring wide bandwidth, high gain, and strong anti-interference capability, is a robust solution for WLAN access points and internet of things gateways. Full article

This paper proposes a rotation-locking alignment scheme and system based on a Gaussian beam addressing the relative displacement between the receiver and the spot center during the fine tracking phase of spaceborne laser communication APT technology caused by platform vibration, temperature variations and other factors. By rotational scanning fitting, the offset angle and offset distance of the receiver relative to the spot center can be derived and achieve high-precision adaptive tracking. The simulated result demonstrates that the fitting distance error of this scheme is less than 1%, and the fitting angle error is less than π/32. At the same time, the system prototype is developed to conduct ground-based validation experiments, including the static test and outdoor link establishment test. The system prototype features simpler structure, lower computational complexity, and easier integration, satisfying the miniaturization and lightweight design requirements for spaceborne laser communication terminals. The test results verify the system can successfully establish stable laser communication links rapidly. Full article