Search Results (5,734)

Safe and energy-aware navigation is still difficult for unmanned surface vehicles (USVs), especially in cluttered waters where obstacles, smooth motion, and wind or current effects must be considered at the same time. If these issues are handled separately, the path may become longer and the vehicle may turn more often, which raises propulsion effort and hurts stability. To reduce these problems, a hybrid path planning method called ${\theta }^{\ast }$-APF-Q is proposed, and it combines global planning, learning-based decisions, and local adjustment in a three-layer structure. First, an any-angle ${\theta }^{\ast }$ global planner is employed to generate a near-optimal backbone trajectory by line-of-sight pruning, thereby reducing redundant waypoints and limiting detours. Second, an enhanced tabular Q-learning model is executed in an expanded eight-direction action space, and policy learning is guided by a multi-objective reward that jointly encourages distance reduction, alignment with ocean current and wind-induced forces for energy saving, smooth heading variation to suppress excessive steering, and maintenance of a safety margin near obstacles. Third, an adaptive artificial potential field (APF) module is used for real-time local correction, providing repulsion in high-risk regions and assisting trajectory smoothing to reduce unnecessary turning operations. A decision bias strategy further couples instantaneous APF forces with long-term state–action values, while the influence weight is adaptively adjusted according to environmental complexity. The algorithm is validated on the randomly generated marine grid maps and on the real-world satellite map scenario, with comparisons against a conventional four-direction Q-learning baseline. Across randomized tests, average path length, turning frequency, and the composite energy indicator are reduced by 22.3%, 55.6%, and 26.4%, respectively, and the success rate increases by 16%. The results indicate that integrating global guidance, adaptive learning, and local reactive decision making supports practical, energy-aware USV navigation. Full article

Accidental crushing by sows is the primary cause of pre-weaning piglet mortality in intensive production, often due to the spatiotemporal lag of manual inspection. While Internet of Things (IoT) solutions exist, they frequently face challenges such as vision occlusion, high hardware costs, and latency. To address these, this study developed a low-cost multi-modal edge computing system based on TinyML. Using an ESP32-S3 microcontroller, the system employs a “Motion-Gated Acoustic Detection” strategy, activating a lightweight 1D-CNN model to identify piglet screams only when an IMU detects high-risk postural transitions of the sow. Results show the quantized model (5.1 KB) achieves 95.56% accuracy and 2 ms inference latency. The total end-to-end response latency is within 179 ms, ensuring intervention within the early “golden rescue window.” The low-power design enables the battery life to cover the entire lactation period. Field tests demonstrated that the system intercepted identified crushing risks within the monitored cohort, supporting its potential for significantly improving piglet survival probability. This research overcomes the limitations of single-modal monitoring and provides a scalable, cost-effective engineering intervention for enhancing animal welfare and achieving intelligent, unattended supervision in precision livestock farming. Full article

Gait analysis study comparing unicompartmental vs. total knee arthroplasty, differences in knee kinematics: a retrospective cohort study. Background and Objectives: Total knee arthroplasty (TKA) is an effective treatment for advanced knee osteoarthritis, although functional outcomes may remain suboptimal in many patients. Unicompartmental knee arthroplasty (UKA) often provides better functional recovery but shows lower long-term implant survival. Recently, personalized TKA approaches have been developed to improve kinematic restoration and patient satisfaction. This study aimed to compare knee kinematics among patients who underwent personalized TKA, medial UKA, and healthy controls. Materials and Methods: This retrospective cohort study included 9 patients treated with robotic-assisted personalized TKA, 9 patients treated with medial UKA, and 9 healthy controls matched for age, sex, and BMI. Inclusion criteria were age 60–80 years, Kellgren–Lawrence grade III–IV, a minimum follow-up of 12 months, deviation from neutral HKA < 15°, healthy contralateral knee, and high postoperative functional scores. Exclusion criteria included valgus knees (HKA > 180°), postoperative complications, and neuromotor disorders. In the TKA group, a Medial Congruent implant was implanted with ROSA robotic assistance using a restricted kinematic alignment (±5° HKA) and asymmetric intercompartmental balancing. In the UKA group, a fixed-bearing medial implant (Physica ZUK) was used. Gait analysis was performed on a markerless instrumented treadmill (WalkerView™; Dalmine, Italy). Differences between groups were analyzed using one-way ANOVA and Tukey’s post-hoc test (p < 0.05). Results: UKA patients walked with a stiffer knee during stance. Knee range of motion during stance increased from UKA (6.3° ± 7.2°) to TKA (13.6° ± 8.8°, p = 0.045) and to controls (16.6° ± 4.5°, p = 0.02). During loading response, UKA patients showed lower flexion (10.2° ± 6.1°) than TKA (19.4° ± 7.9°, p = 0.049) and controls (19.6° ± 2.8°, p = 0.004). Knee flexion during swing was comparable between UKA and TKA. Conclusions: UKA patients demonstrated reduced knee flexion during early stance compared with robotic-assisted TKA and healthy controls. The observed differences may reflect multiple factors, including surgical technique, implant design, and patient-related characteristics. Because preoperative functional data were not available, potential selection bias cannot be excluded. These findings should be interpreted cautiously and warrant confirmation in larger prospective studies. Full article

As the development of the ocean extends to the deep and open seas, the application of multi-hull floating systems is becoming increasingly widespread, covering offshore oil and gas transfer and material replenishment operations. In multi-body floating systems, the hydrodynamic interactions between adjacent floating bodies significantly affect the overall motion response and load distribution. However, there is currently a lack of systematic experimental research on systems involving three or more units under the combined action of wind, waves, and currents. This study presents a 1:50 scale model experiment on a five-body offshore replenishment station, comprising a central transfer platform and four surrounding vessels. Absolute six-degree-of-freedom motions and relative displacements between the transfer platform and neighboring vessels were measured. The results indicate distinct differences among the units. The peripheral vessels have greater horizontal and yaw motions, while the central units are more restricted. The relative motions are substantially increased for beam and oblique wave conditions, implying increased interaction effects in the gaps between neighboring bodies. Moreover, the combined oblique environmental loading and asymmetric mooring stiffness result in increased global drift and yaw motions. These findings provide benchmark data for numerical validation and practical guidance for the design and operation of multi-body floating systems. Full article

Fully maintenance-free smart collars for range cattle, sheep and deer must survive years of uncontrolled grazing under highly variable shade and motion conditions. This paper presents an ultra-low-power buck converter governed by a fast integral terminal sliding mode controller (FITSMC) with a fixed-time observer. A new reaching law retains the initial sliding manifold and a negative-power term maintains the constant switching gain to preserve robustness near the surface while attenuating chattering without widening the bandwidth. The fixed-time observer estimates the irradiance and load changes and provides a feed-forward correction, tightening the output regulation regardless of initial conditions. Load step tests with moderate resistance swings showed the proposed method recovers noticeably faster and exhibits slightly lower overshoot than a recent method based on a two-phase power reaching law, while visible inductor current spikes are also suppressed. Simulations under daily grazing profiles confirmed tight output regulation adequate for microwatt data logging and periodic long-range (LoRa) bursts. The sleep mode quiescent current remained in the 9 microamps range, eliminating the need for manual recharge across multi-season field deployments. By integrating robust power electronics with collar-grade solar harvesting, the circuit offers a truly maintenance-free energy path for untethered livestock wearables and supports sustainable precision agriculture. Full article

Background and Objectives: This study aimed to evaluate the effectiveness of Transfer of Energy Capacitive and Resistive (TECAR) therapy in treating active myofascial trigger points (MTrPs) in the upper trapezius muscle (UT) and to compare it with the effects of dry needling (DN). Materials and Methods: We recruited 29 men (mean age: 35.52 ± 5.73 years) with active MTrPs in the UT. Participants were randomly assigned to two groups: TECAR (n = 17) and DN (n = 12). Treatment was administered twice, with a 7-day interval between sessions. PPT, pain intensity (NRS), UT muscle strength (dynamometer), and cervical spine range of motion (ROM) were measured before treatment, immediately after each therapy session, and at a 30-day follow-up. Data were analyzed using parametric or non-parametric tests depending on data distribution (p < 0.05). Results: Both groups showed significant increases in PPT, but TECAR reduced NRS significantly more than DN (p < 0.001), demonstrating superior immediate analgesia. While TECAR temporarily decreased unaffected UT strength, it provided broader improvements in cervical mobility (flexion: 19.5%, contralateral rotation: 13.1%). Over 30 days, both groups improved PPT (TECAR: ~110%; DN: ~63%) and NRS (TECAR: ~97.1%; DN: ~84.5%). The TECAR group consistently outperformed DN in long-term pain reduction and achieved more substantial improvements in ROM. Conclusions: TECAR therapy appears to provide immediate and longer-term analgesic effects in the treatment of active MTrPs in the UT, although its impact on cervical ROM seems relatively limited compared with DN. It may therefore represent a useful, though less commonly applied, option for MTrPs management. Full article

To address the demand for a micro-power supply for vehicle suspension control, a novel harvester is proposed to recover vortex-induced vibration energy in the wake of a shock absorber. A suspension dynamic model was established to simulate the spring compression process and identify the wind-shielding condition. The spring-shock absorber assembly was then simplified as a stepped cylinder with two cross-sections. Flow-field analysis showed that the size, shape, and rising angle of the wake vortices were affected by the bluff-body geometry, Reynolds number, and boundary conditions. The downwash motion was found to directly influence vortex development, and two new vortex-connection modes were identified. These results provided guidance for harvester optimization. A two-way fluid–structure interaction model was developed to describe the electromechanical conversion behavior of the proposed harvester under flow excitation. Numerical results showed that the output voltage increased with vehicle speed. An average peak voltage of 1.82 V was obtained when the piezoelectric patches were installed two larger-cylinder diameters downstream. The optimal patch length was 120 mm, and further increasing the length did not significantly improve the harvesting performance. Finally, a full-scale prototype was tested, and the measured voltage agreed well with the simulation results. The proposed harvester can therefore serve as a potential micro-power source for low-power suspension electronics. Full article

Background: Knee osteoarthritis (KOA) is a major cause of pain, mobility limitation, and increased fall risk among older adults. Gait dysfunction, characterized by spatiotemporal and kinematic alterations, is a key functional consequence of KOA. While sagittal-plane gait deviations are well-established, multiplanar kinematic changes—particularly in the frontal and transverse planes—remain less clearly understood. This study aimed to compare three-dimensional gait characteristics between older adults with and without KOA. Methods: Ninety older adults (45 with KOA and 45 controls) completed gait assessments using a VICON™ motion capture system. Participants walked at a self-selected speed along a straight walkway without turning movements during data collection. Spatiotemporal parameters and lower-limb joint kinematics (hip, knee, and ankle) were recorded during key gait phases: initial contact, mid-stance, toe-off, and mid-swing. Group comparisons were performed using independent t-tests with statistical significance set at p < 0.05. Results: Compared with controls, participants with KOA demonstrated significantly slower gait velocity (p = 0.001), reduced cadence (p = 0.020), shorter stride length (p = 0.011), increased step time (p = 0.006), prolonged double support time (p = 0.009), and reduced single support time (p = 0.012). Kinematic analysis revealed greater knee adduction at initial contact (p = 0.001), reduced hip adduction (p = 0.002) and greater knee adduction (p = 0.003) during mid-stance, and increased ankle plantarflexion at toe-off (p = 0.004) in the KOA group. No significant between-group differences were observed during the mid-swing phase. Conclusions: Older adults with KOA exhibit distinct spatiotemporal and multiplanar kinematic gait alterations, particularly during weight-bearing phases. These changes may reflect adaptive gait patterns associated with joint dysfunction rather than definitive compensatory mechanisms. Three-dimensional gait analysis may provide valuable biomechanical insights to support early identification of mobility impairments and inform targeted rehabilitation planning in individuals with KOA. Full article

Objectives: To quantitatively assess masticatory function with instrumental measures in a group of patients suffering from temporomandibular joint (TMJ) arthralgia, and to compare the results with symptom-free controls. Methods: Data of bite force, variance-of-hue-based (VOH) chewing efficiency, chewing frequency, the bilateral pressure pain threshold (PPT) of the temporalis and masseter muscles, and mandibular range of motion (RoM) were collected in a sample of TMJ arthralgia patients (n = 14) and controls (n = 19). The diagnosis of arthralgia was obtained following the DC/TMD protocol. Comparison between the groups was conducted using independent samples t-tests (level of significance α = 0.05). Associations within the arthralgia group were assessed using Pearson’s correlation coefficient. Results: In comparison to the controls, arthralgia patients showed significantly restricted pain-free and maximum unassisted mouth opening (p < 0.001, p = 0.022 respectively) as well as a significant decrease in both bite force (p < 0.001) and chewing frequency (p = 0.01). The average chewing efficiency for the arthralgia group was 0.14 ± 0.08 VOH. The PPT for both masseter muscles did not show significant differences in comparison to the control group. Conclusions: In patients with TMJ arthralgia, functional markers such as RoM, bite force, and chewing frequency exhibited significant limitations compared to the control group. The employment of instrumental measurements in the documentation of symptoms in clinical practice provides an objective basis for the assessment of functional limitations. Hence, we recommend integrating them into the longitudinal patients’ observation during therapy. Full article

Electron fields (and more generally spinor fields) with a vortex structure in free space that allows them to have arbitrary integer orbital angular momentum along the direction of motion have been studied for some time. We point out that there are several ways to calculate the local velocity of the electron field, defined as the ratio of momentum density to energy density, and that all but one show a singular vorticity at the vortex line. That one, using the Dirac bilinear current with no derivatives, is the only one so far (to our knowledge) studied in the literature in this context and we further show how to understand an apparent conflict in the existing results. The momentum densities corresponding to the three possible velocity fields give different physical results, in particular regarding the electron induced quantum superkicks given to small electron-absorbing test objects. Full article

Rigid-body chain following on piecewise analytic paths is a fundamental subroutine in motion planning and multibody simulation. The problem is nontrivial when only the leader trajectory of the first node is available: enforcing fixed inter-node distances reduces to circle–curve intersection, which is generally multi-valued and becomes particularly challenging near non-smooth junctions. We present a Dichotomy Geometric Path Search (DGPS) framework that converts each constraint into a one-dimensional root-finding task and resolves the branch selection through no-backtracking ordering: at every time step, the admissible solution for the current node is the nearest feasible root in the past relative to its immediately preceding node. DGPS combines backward bracketing with bisection, achieving robust convergence. Compared with the inverse Jacobian method, which maps end-effector velocities to joint velocities via explicit inversion, the proposed approach avoids Jacobian inversion and globally coupled nonlinear solves. We further characterize the local structure of the zero set and establish monotonicity/uniqueness conditions that justify stable root selection across piecewise junctions. Extensive tests on representative piecewise trajectories (line–arc–line, polylines with corners, piecewise sinusoids, and time reparameterization) show that DGPS enforces distance constraints to near machine precision, produces interpretable speed/acceleration transients around non-smooth events, and exhibits computational costs consistent with iteration difficulty. The results support DGPS as a general, efficient solver requiring only the prescribed leader trajectory. Full article

Background: Intrinsic foot muscle strengthening and orthotic devices such as toe spacers are commonly used to improve foot alignment and function. However, evidence regarding the combined effects of strengthening exercises and interdigital spacers remains limited. Objective: To examine whether adding a silicone toe spacer to a foot strengthening exercise program provides additional benefits compared with exercise alone. Design: Randomized controlled trial. Setting: University biomechanics laboratory. Participants: Twenty-five healthy adults (mean age 23.8 ± 1.3 years) without lower limb injury or neurological disorders were randomly allocated to one of two intervention groups. Interventions: Participants performed a six-week foot strengthening program (22 sessions). One group performed exercises alone, while the second group performed the same exercises while wearing a silicone interdigital toe spacer. Main outcome measures: The primary outcome was hallux valgus angle. Secondary outcomes included active and passive hallux range of motion (ROM), ankle dorsiflexion ROM (weight-bearing lunge test), navicular drop, and postural stability during single-leg stance assessed using center-of-pressure (CoP) measures. Results: Both groups demonstrated improvements over time in hallux valgus angle (p = 0.001, η² = 0.361), active hallux range of motion (p < 0.001, η² = 0.545), and ankle dorsiflexion (p < 0.001). However, no significant between-group differences were observed for the primary outcome or most secondary outcomes. A significant time × group interaction was observed only for passive hallux range of motion (p = 0.040, η² = 0.170), indicating greater improvement in the exercise-only group. Navicular drop and postural stability variables did not change significantly. Conclusions: A six-week foot strengthening program improved hallux alignment, hallux mobility, and ankle dorsiflexion in healthy adults. The addition of a silicone toe spacer did not provide additional short-term benefits compared with exercise alone. Full article

The navigation of ships in complex shallow water areas is constrained by various factors such as water depth, channel boundaries, and environmental interference. Therefore, it is crucial to improve the adaptability and effectiveness of collision avoidance decisions for ships in complex shallow water scenarios. To address these issues, this paper proposes a multi-factor constrained autonomous decision-making method for complex shallow water vessel maneuvering. Firstly, a digital transportation environment was constructed by combining dynamic and static information, such as water depth, tides, channel boundaries, changes in maneuvering characteristics, and navigation rules, and a navigable water area model that was suitable for shallow water was proposed. Then, considering the constraints of ship maneuverability and the navigation environment, a shallow water ship motion model affected by wind flow was developed. A complex shallow water adaptive maneuvering coupled decision-making method was constructed, considering the influence of ship navigation rules and channel constraints. This method utilizes the Kalman filtering algorithm to correct residuals and predict the maneuvering of the target vessel. Integrated improved heading control and guidance algorithms achieved automatic heading control and future position prediction. Through testing and verification in the complex waters of the Yangtze River estuary, the results show that the autonomous collision avoidance decision-making method proposed in this paper can effectively make collision avoidance decisions in complex multi-ship shallow water areas. This study can provide innovative and practical solutions for the technological development of autonomous ship collision avoidance decision-making. Full article

Change-of-direction (COD) ability is a key determinant of performance in youth basketball, yet the relative contribution of braking, re-acceleration, trunk motion, and body composition remains unclear. Thirty-two male U18 national-team level players (17.6 ± 0.7 y; 194.8 ± 4.5 cm; 89.1 ± 9.4 kg) completed whole-body and segmental DEXA assessment, bilateral countermovement jump (CMJ) testing and a 505 agility test (505) instrumented with a local positioning system. Mean COD times were 2.36 ± 0.09 s (505) and 1.84 ± 0.08 s (303), with maximal deceleration (DcMax) of −7.26 ± 0.52 m·s⁻². Paired t-tests showed no significant differences between right- and left-leg turns for any variable (all p > 0.25), indicating symmetrical COD performance. General linear models revealed that DcMax was the only consistent predictor of COD time (505: R² = 0.53, F (7,24) = 3.91, p = 0.006, partial η² = 0.31; 303: R² = 0.49, F(9,22) = 2.34, p = 0.050, partial η² = 0.34), with a smaller additional effect of approach speed for the 303 segment (p = 0.049). Body-composition indices and CMJ variables showed only weak, non-significant correlations with COD time (|r| < 0.30, p > 0.05), and neither centripetal force nor trunk angular speed was associated with performance. These findings indicate that high-intensity braking capacity, rather than muscle mass or jump power per se, is the primary mechanical determinant of COD in elite youth basketball, suggesting that deceleration-focused training should be prioritized in performance development. Full article

Multi-purpose platforms, which combine renewable energy generation devices and diverse functionalities, are a smart way to expand the applications of offshore platforms. An environmentally friendly multi-purpose offshore platform is proposed by the ‘Blue Growth Farm’ project, which includes a wind turbine, a set of wave energy converters, and an aquaculture system. To assess its feasibility and performance, a field experiment is conducted at an offshore site in Italy using a 1:15 scaled outdoor platform prototype. To provide comprehensive insights into the platform’s behavior, in the present work, aero–hydro–servo–elastic coupled numerical models based on the blade element method and potential flow theory are developed for various experimentally tested configurations of this multi-purpose platform. Time domain analyses are conducted to investigate the performance of the outdoor prototype platform under the recorded realistic environmental loads from the field experiment. The numerical results, including platform motion, mooring line tension forces, and wind turbine responses, agree with the corresponding experimental records. For example, the absolute mean value errors for platform roll and pitch motions are approximately 1 degree, validating the developed numerical model. Meanwhile, the present comparative study demonstrates the feasibility of the proposed multi-purpose concept and can provide a reference for similar projects in the future. Full article