Angle Variance Research Articles

Distributed Improved RILOS Guidance-Based Formation Control of Underactuated ASVs for Cooperative Maritime Search

A distributed improved robust integral line-of-sight (RILOS) guidance-based sliding mode controller is designed for multiple underactuated autonomous surface vessels (ASVs) to perform cooperative maritime search operations. First, a parallel circle search pattern is designed based on the detection range of ASVs, which can provide the reference formation shape. Second, an improved RILOS method is presented by introducing an integral term into the improved robust LOS method, which can counteract the disadvantageous effect of the unknown sideslip angle and kinematic discrepancy simultaneously. Third, distributed improved RILOS guidance is presented by integrating the extended second-order consensus algorithm into the improved RILOS method; then, the desired heading angle and desired velocity are generated for the control system simultaneously. Finally, the fuzzy logic system is integrated into the sliding mode control (SMC) method to approximate the unknown nonlinear function; then, a distributed improved RILOS guidance-based SMC controller is presented for multiple ASVs. The close-loop signals are proved to be stable by the Lyapunov theory. The effectiveness of the presented method is verified by multiple simulations.

Fracturability of shale based on rock brittleness and natural fracture tensile reactivation

Exploration and development practices have proved that fracturability evaluation is the primary basis for sucessful fracturing operations. Current studies mainly rely on using traditional physical parameters to evaluate shale fracturability. However, fracture morphology and the extension of natural fractures during fracturing are also crucial for shale fracturability evaluation. In this study, the correlations among factors and rock fracture complexity and natural fracture opening degree were analyzed through 40 sets of related experiments, proposing a new method for shale fracturability evaluation that considers Young's Modulus, shear expansion angle, residual strain, approach angle, and stress variance coefficient. Finally, taking the shale gas field in the Sichuan Basin as an example, a comprehensive evaluation model of shale fracturability was established by using the gray correlation method combined with the core experimental data. One well was selected to compare and analyze the fracturability profile with the stimulated reservoir volume. The results show thatthe peak strain has the most significant influence on the shale fracture complexity, followed by the shear expansion angle and Young's Modulus. The approach angle and the stress difference coefficient affect the degree of natural fracture opening at the same time. The model is accurate because the fractureability values match the study block's stimulated reservoir volume data. This new method of shale fractureability evaluation offers important technology for predicting the fractureability of shale gas reservoirs and optimizing operation schemes.

Design and Experiment of an Independent Leg-Type Chassis Vehicle Attitude Adjustment System

In response to the current low work efficiency of soil ridge-working machinery, as well as its poor stability, passability, and adaptability, this paper designs an independent leg-type working platform that can autonomously adjust its vehicle attitude through LiDAR scanning in a soil ridge-working environment. The platform, in terms of its mechanism and structural design, adopts dual parallelogram mechanisms, dual lead screw mechanisms, and independent column leg mechanisms, with a maximum adjustable ground clearance of 107 mm and a maximum wheelbase adjustment of 150 mm. A gyroscope is mounted at the center of the platform for attitude adjustment, ensuring the accurate data collection of the ultrasonic ranging module. Moreover, the platform adopts an adaptive adjustment method based on vehicle attitude and soil ridge shape parameters, obtaining soil ridge parameters through LiDAR and combining ultrasonic ranging module data with stepper motor pulse signals to obtain the absolute vehicle attitude parameters, using first and second linear regression methods to adjust the vehicle attitude and other working parameters. A prototype was also created, and the test data from the soil obtained through experiments show that, after leveling with the gyroscope leveling algorithm, the average value of the pitch angle is up to 0.6154°, and the average value of the roll angle is up to 0.9989°, with the maximum variance of the pitch angle being 0.0474° and the maximum variance of the tilt angle being 0.1320°. After the ultrasonic ranging module data are filtered by the Kalman filter, the maximum variance is 0.0304, and after applying the final fusion algorithm, the maximum variance is only 0.0085. The LiDAR measurement width value deviates from the actual width value by no more than 1.0 cm, and the LiDAR measurement height value deviates from the actual height value by no more than 1.0 cm. The platform’s actual adjusted width deviates from the actual soil ridge width by no more than 2.0 cm, and the platform’s actual adjusted height deviates from the actual soil ridge height by no more than 1.2 cm. This platform can improve the passability, adaptability, and stability of agricultural machinery in soil ridge work and provide technical references for subsequent related research.

A Virtual Synchronous Generator-Based Control Strategy and Pre-Synchronization Method for a Four-Leg Inverter under Unbalanced Loads

Virtual synchronous generator (VSG) control has positive effects on the stability of microgrids. In practical power systems, both single-phase loads and three-phase unbalanced loads are present. The four-leg inverter is an alternative solution for the power supply of unbalanced loads and grid connections. The traditional VSG control strategy still faces challenges when using a four-leg inverter to provide a symmetrical voltage and stable frequency in the load power supply and pre-synchronization. This paper proposes a VSG-based control strategy along with a pre-synchronization method for four-leg inverters. An improved VSG control strategy is put forward for four-leg inverters. The improved virtual impedance control and power calculation methods are integrated into the control loop to suppress the voltage asymmetry and frequency ripples. Building on the improved VSG control strategy, a pre-synchronization control approach is proposed to minimize the amplitude and phase angle discrepancies between the inverter output voltage and the power grid voltage. In addition, an optimized design method for control parameters is presented to improve VSG dynamic performance. A hardware prototype of the four-leg inverter is built; the results show that the voltage unbalance ratio can be reduced by 89%, and the response time can be shortened by 50%.

Medial Closing Wedge High Tibial Osteotomy Accurately Corrects Genu Valgum without Iatrogenic Deformity or Complications: A Consecutive Series of Thirty-one Procedures.

Angular deformities of the tibia and femur lead to mechanical axis deviation (MAD) of the lower limb and malorientation of the joints adjacent to the deformity. The current study analyses the outcomes of using a medial closing wedge high tibial osteotomy (MCWHTO) for the management of genu valgum with high medial proximal tibial angle (MPTA), and combined MCWHTO with lateral opening-wedge distal femoral osteotomy (LOWDFO) in the setting of concomitant genu varum with low lateral distal femoral angle (LDFA). There were 18 high tibial osteotomy (HTO)-only and 13 combined HTO + distal femoral osteotomy (DFO) procedures performed. The primary radiographic outcome variables included postoperative MPTA and MAD (in mm). The accuracy of MAD correction was expressed as a percentage. The postoperative posterior proximal tibial angle (PPTA) and limb length discrepancy (LLD) were also measured as secondary radiographic outcome variables. The clinical outcome variables included intraoperative surgical complications (e.g., hinge fracture), all-causes for revision, union rate, time to union, and postoperative knee range of motion. Functional outcomes used included the LDSRS, PROMIS, and EuroQOL scores. The mean preoperative MPTA was 92.9° (SD = 1.81, range: 88-96). After surgical correction, the mean MPTA was 86.0° (SD = 1.80, range: 83-90) (p < 0.0001). The mean preoperative MAD was 32.5 mm (SD = 20.16, range: 10-77) lateral to the centre of the knee joint. The mean postoperative MAD was 2.44 mm medial to the centre of the joint (SD = 7.13, range: 13 medial - 15 lateral) (p < 0.0001). The mean change in MAD achieved through surgical correction was 38.16 mm (SD = 17.94, range: 13-77). The accuracy of MAD correction was 96.1% (SD = 0.06%, range: 81.25-100%). The time to unassisted WB was a mean of 75 days (SD = 44.5, range: 44-242).There was a single stable hinge fracture and one case of chronic regional pain syndrome diagnosed. There were no cases of non-union and no indications for revision surgery in any case. Medial closing wedge high tibial osteotomy is an effective surgical procedure for the management of genu valgum deformity. The MPTA, LDFA, and MAD can be accurately corrected without significantly altering PPTA or limb length. It may be combined with open lateral distal femoral osteotomy for cases with femoral and tibial contributions to deformity without significantly impacting clinical outcomes. Functional outcomes, specifically relating to self-image are significantly improved after the MCWHTO has been performed. Sheridan GA, Page BJ, Greenstein MD, et al. Medial Closing Wedge High Tibial Osteotomy Accurately Corrects Genu Valgum without Iatrogenic Deformity or Complications: A Consecutive Series of Thirty-one Procedures. Strategies Trauma Limb Reconstr 2024;19(2):82-86.

Slope Stability Analysis of Rockfill Embankments Considering Stress-Dependent Spatial Variability in Friction Angle of Granular Materials

Slope stability is a major safety concern of rockfill embankments. Since rockfills are incohesive materials, only friction angle is considered as a shear strength parameter in the slope stability analysis of rockfill embankments. Recently, it was found that confining pressure can significantly affect the mean value and variance of the friction angle of rockfills. Since the confining pressure spatially varies within a rockfill embankment, the effect of stress-dependent spatial variability in the friction angle of rockfills should be investigated for slope stability evaluation of rockfill embankments. In the framework of the Limit Equilibrium Method (LEM), an approach is proposed for the slope stability analysis of rockfill embankments considering the stress-dependent spatial variability in the friction angle. The safety factors of slope stability are computed with variable values of the friction angle at the bases of slices which are determined by the stress-dependent mean value and variance of the friction angle of rockfills. The slope stability of a homogeneous rockfill embankment is analyzed to illustrate the proposed approach, and a parametric analysis is carried out to explore the effect of variation in the parameters of the variance function of friction angle on slope stability. The illustrative example demonstrates that the stress-dependent spatial variability of friction angle along the slip surface is obvious and is affected by the location of the slip surface and the loading condition. The effects of the stress-dependent spatial variability of the friction angle on the slope stability of high rockfill embankments should be considered.

Three-Dimensional Human Posture Recognition by Extremity Angle Estimation with Minimal IMU Sensor.

Recently, posture recognition technology has advanced rapidly. Herein, we present a novel posture angle calculation system utilizing a single inertial measurement unit and a spatial geometric equation to accurately identify the three-dimensional (3D) motion angles and postures of both the upper and lower limbs of the human body. This wearable system facilitates continuous monitoring of body movements without the spatial limitations or occlusion issues associated with camera-based methods. This posture-recognition system has many benefits. Providing precise posture change information helps users assess the accuracy of their movements, prevent sports injuries, and enhance sports performance. This system employs a single inertial sensor, coupled with a filtering mechanism, to calculate the sensor's trajectory and coordinates in 3D space. Subsequently, the spatial geometry equation devised herein accurately computed the joint angles for changing body postures. To validate its effectiveness, the joint angles estimated from the proposed system were compared with those from dual inertial sensors and image recognition technology. The joint angle discrepancies for this system were within 10° and 5° when compared with dual inertial sensors and image recognition technology, respectively. Such reliability and accuracy of the proposed angle estimation system make it a valuable reference for assessing joint angles.

Distal radius fractures after 75 years of age: are six-month functional and radiological outcomes better with plate fixation than with conservative treatment?

BackgroundSurgery and non-operative treatment produce similar 1-year functional outcomes in patients older than 65 years. Data are lacking for patients older than 75 years. The main objective of this study was to compare surgical vs. non-operative treatment regarding short-term outcomes in patients older than 75 years. In addition to an overall analysis, sub-group analyses were done in patients with displacement and severe displacement (>20 ° posterior tilt). HypothesisSurgery provides better clinical and radiological outcomes than does non-operative treatment. Patients and methodsPatients older than 75 years at the time of a distal radius fracture were included prospectively over a 2-year period. A follow-up duration of at least 6 months was required. Treatment choices were based on displacement, Charlson’s Co-morbidity Index, and patient autonomy. Surgery consisted in open fixation using an anterior locking plate and non-operative treatment in a short arm cast without reduction. The main assessment was based on clinical criteria: range of motion, strength, visual analogue scale (VAS) scores, the short version of the Disabilities of the Arm, Shoulder, and Hand tool (QuickDASH), the Patient Rated Wrist Evaluation (PRWE), and the 36-Item Short Form Health Survey (SF-36). The secondary assessment criteria were the radiological outcomes and the complications. Results74 patients were included, among whom 24 were treated surgically and 50 non-operatively. At 1.5 months, surgery was associated with significantly better results for flexion, ulnar inclination, and supination, with range increases of at least 7 ° vs. non-operative treatment, and with greater dorsal angle and ulnar variance values (p < 0.05 for all comparisons). At 6 months, pronation and the radio-ulnar index were better with surgery (p < 0.05 for both comparisons). In the patients with displacement or severe displacement, surgery was associated with 10° gains vs. conservative treatment for flexion, ulnar inclination, and supination at 1.5 months (p < 0.05 for all comparisons). DiscussionIn patients older than 75 years, surgery for distal radius fracture was associated with significantly better clinical and radiological outcomes within 6 months. Surgery is recommended for displaced and severely displaced distal radius fractures to expedite the recovery of joint motion ranges. Beyond 6 months, the outcomes are similar. Level of evidenceIII.

A New Perspective to Assess Patellar Surface-Trochlear Sulcus Compatibility: Narrowed Patellar Angle is Associated with Greater Trochlear Sulcus Angle

Objective: In this study, the relationship between patella angle - trochlear sulcus angle (TSA) discrepancy was investigated. A specific cutoff value of patella angle (PA), TSA, trochlear groove depth (TGD), and medial trochlear/lateral trochlear length (MT/LT) ratio for effusion, fat-pad edema, chondromalacia, meniscal and ligament tear were investigated. By doing so, to the best of our knowledge, we bridged the gap in literature since these relationships between the above-mentioned measurements have almost never been examined. Methods: A total of 446. patients were evaluated on magnetic resonance imaging. PA and TSA were calculated with. the highest specificity and sensitivity in predicting effusion, fat-pad edema, and patellar chondromalacia. A specific cutoff value of PA, TSA, TGD and MT/LT for effusion, fat-pad edema, chondromalacia, meniscal tear, and ligament tear were investigated. Results: A low-level and insignificant correlation was found between PA and TSA in the negative direction. TSA value. with the highest sensitivity and specificity in predicting the presence of effusion, fat-pad, and chondromalacia was found ≤131, ≤129.6, and &gt;125.8, respectively. Tibial tubercle-trochlear groove (TT-TG) distance. measurement was significantly less in the group with Medial Meniscus (MM) rupture. Increased TT-TG distance posed a risk for quadriceps tendinosis 1.127 times and increased medial trochlea length (MT) posed a risk for quadriceps tendinosis 1.167 times. Conclusion: Certain cutoff values of PA and TSA may predispose risk for meniscal tear, effusion, fat-pad edema, and chondromalacia. A negative correlation was present between the patella angle and TSA.

Bi-level game theoretic approach for robust design: A case study of path-generating four-bar

This study addresses the bi-level multi-objective optimization problems (MOP) that raise in robust design and optimization of engineering systems through establishing a state-of-the-art game theoretic scenario. A novel leader-follower decentralized decision-making scenario is proposed, leveraging the synergy of game theory, Robust Design Optimization (RDO), Monte Carlo Simulation (MCS), and Artificial Intelligence (AI). The proposed algorithm can be employed for optimum robust Pareto design of a wide range of dynamical systems. In order to achieve a robust design, both the mean and variance of each objective function are considered as players in a multi-agent game setting. In this approach, both Stackelberg and cooperative games are utilized to model the behaviors of the players. Genetic Programming (GP) meta-models are employed to capture the Stackelberg protocol between two levels specifically for constructing the follower's rational reaction set (RRS). Additionally, the Nash bargaining function is -utilize to model the cooperative behaviors among players in each level. The proposed approach is applied and demonstrated through a case study involving multi-objective robust design of planar four-bar linkages. In this manner, four objective functions are assigned to four players within the system. Each player is responsible for optimizing a specific objective criterion, namely the mean of tracking error (TE), variance of tracking error, mean of transmission angle and variance of transmission angle (TA) of the linkage. As a result, the four-objective optimization problem of mechanism is transformed into a single-objective robust synthesis problem. The comparisons of the results show a significant enhancement in the robust behavior of the linkage, while ensuring that deterministic criteria such as quality of motion and precision are preserved.

A DEEP LEARNING MODEL FOR EFFECTIVE CYCLONE INTENSITY ESTIMATION

Tropical cyclones are extremely dangerous weather phenomena that cause significant damage to human life, property, economy, agriculture, and development. Currently, various methods are being used to estimate cyclone intensity. One such method is the objective deviation angle variance technique, which estimates the intensity of tropical cyclones from satellite infrared imagery by performing statistical analysis of the brightness of those images. The limitation of this method is that it requires images with properly marked cyclone centers. Another method to estimate cyclone intensity involves feature engineering and machine learning, however, which is a manual process. To address the limitations associated with the above conventional methods, a new approach is being proposed that uses a deep learning mechanism to design a CYCLONE NETWORK (CY-Net) model. This model will estimate the cyclone intensity by using INSAT-3D infrared (IR) images. The CY-Net model is developed based on structural, intensification, and landfall features along with biasing parameters such as wind speed, sea level pressure, and sea surface temperature. The INSAT 3D data is given as input to the model for training, testing, and validation. It undergoes convolution along with the Re-lu activation function to generate feature maps, max pooling, sub-convolution, and fully connected layers. The stochastic gradient descent factor is measured to implement the backpropagation. The Stochastic gradient and backpropagation network are implemented to obtain the best filter coefficients. The trained, tested, and validated model is deployed in Python-flask for web application and then hosted using the web servers for web application. This approach uses advanced machine learning techniques to estimate cyclone intensity and has the potential to improve accuracy and reduce manual effort.

SAR Target Recognition Method based on Adaptive Weighted Decision Fusion of Deep Features

Background: This paper proposes a synthetic aperture radar (SAR) target recognition method based on adaptive weighted decision fusion of multi-level deep features. Methods: The trained ResNet-18 is employed to extract multi-level deep features from SAR images. Afterwards, based on the joint sparse representation (JSR) model, the multi-level deep features are represented to obtain the corresponding reconstruction error vectors. Considering the differences in the abilities of different levels of features to distinguish the target, the reconstruction error vectors are analyzed based on entropy theory, and their corresponding weights are adaptively obtained. Finally, the fused reconstruction error result is obtained through adaptively weighted fusion, and the target label is determined accordingly. Results: Experiments are conducted on the Moving and Stationary Target Acquisition and Recognition (MSTAR) dataset under different conditions, and the proposed method is compared with published methods, including multi-feature decision fusion, JSR-based decision fusion and other types of ResNets. Conclusion: The experimental results under standard operating condition (SOC) and extended operating conditions (EOCs) including depression angle variance and noise corruption validate the advantages of the proposed method.

Is AI 3D-printed PSI an accurate option for patients with developmental dysplasia of the hip undergoing THA?

BackgroundIn traditional surgical procedures, significant discrepancies are often observed between the pre-planned templated implant sizes and the actual sizes used, particularly in patients with congenital hip dysplasia. These discrepancies arise not only in preoperative planning but also in the precision of implant placement, especially concerning the acetabular component. Our study aims to enhance the accuracy of implant placement during Total Hip Arthroplasty (THA) by integrating AI-enhanced preoperative planning with Patient-Specific Instrumentation (PSI). We also seek to assess the accuracy and clinical outcomes of the AI-PSI (AIPSI) group in comparison to a manual control group.MethodsThis study included 60 patients diagnosed with congenital hip dysplasia, randomly assigned to either the AIPSI or manual group, with 30 patients in each. No significant demographic differences between were noted the two groups. A direct anterior surgical approach was employed. Postoperative assessments included X-rays and CT scans to measure parameters such as the acetabular cup anteversion angle, acetabular cup inclination angle, femoral stem anteversion angle, femoral offset, and leg length discrepancy. Functional scores were recorded at 3 days, 1 week, 4 weeks, and 12 weeks post-surgery. Data analysis was conducted using SPSS version 22.0, with the significance level was set at α = 0.05.Results and conclusionThe AIPSI group demonstrated greater prosthesis placement accuracy. With the aid of PSI, AI-planned THA surgery provides surgeons with enhanced precision in prosthesis positioning. This approach potentially offers greater insights and guidelines for managing more complex anatomical variations or cases.

Enhancing green sea turtle (Chelonia mydas) conservation for tourists at Little Liuqiu island, Taiwan: Application of deep learning algorithms

Observing marine life has emerged as a pivotal catalyst for the growth of the Blue Economy. Yet, overzealous and recurrent observations may exert undue stress on marine creatures, thereby complicating the sustainable management of marine assets. After the easing of Covid-19 pandemic restrictions, a notable influx of tourists to Little Liuqiu Island, Taiwan puts considerable stress on its green sea turtle population. This surge intensified incidents of illegal harassment, triggering concerns from both the local community and administrative bodies. The prevailing challenge is to ensure tourists observe these turtles with respect, refraining from behaviors such as touching or pursuing them. Addressing this, our study harnesses deep learning algorithms to equip ecotourism operators and tourists with tools to detect green sea turtles across diverse coastal terrains, reinforcing conservation efforts. Our analysis scrutinized object detection AI models, namely YOLOv3, YOLOv5s, and YOLOv5l. Fieldwork was undertaken on the island to gather ample training images, capturing elusive green sea turtles in various settings, from coastline strolls to drone imagery. Supplemental images sourced from local social media platforms were later added. Contrary to expectations, we found that merely expanding the training dataset did not guarantee improved outcomes. Instead, the variance in image content, considering distances, angles, and turtle appearances, played a pivotal role in enhancing model precision. Through our experimentation, the streamlined YOLOv5s model consistently eclipsed its more complex counterparts in performance. An AI service, underpinned by the YOLOv5s model, has been launched to distinguish between green sea turtle types for tourist-focused conservation initiatives. Future iterations will incorporate user feedback to refine accuracy. Our research breaks new ground, spotlighting the intricacies of gathering natural environment data, pinpointing optimal AI models, and evaluating their practical implications for green sea turtle conservation.

Closed-Loop Wearable Device Network of Intrinsically-Controlled, Bilateral Coordinated Functional Electrical Stimulation for Stroke.

Innovative functional electrical stimulation has demonstrated effectiveness in enhancing daily walking and rehabilitating stroke patients with foot drop. However, its lack of precision in stimulating timing, individual adaptivity, and bilateral symmetry, resulted in diminished clinical efficacy. Therefore, a closed-loop wearable device network of intrinsically controlled functional electrical stimulation (CI-FES) system is proposed, which utilizes the personal surface myoelectricity, derived from the intrinsic neuro signal, as the switch to activate/deactivate the stimulation on the affected side. Simultaneously, it decodes the myoelectricity signal of the patient's healthy side to adjust the stimulation intensity, forming an intrinsically controlled loop with the inertial measurement units. With CI-FES assistance, patients' walking ability significantly improved, evidenced by the shift in ankle joint angle mean and variance from 105.53° and 28.84 to 102.81° and 17.71, and the oxyhemoglobin concentration tested by the functional near-infrared spectroscopy. In long-term CI-FES-assisted clinical testing, the discriminability in machine learning classification between patients and healthy individuals gradually decreased from 100% to 92.5%, suggesting a remarkable recovery tendency, further substantiated by performance on the functional movement scales. The developed CI-FES system is crucial for contralateral-hemiplegic stroke recovery, paving the way for future closed-loop stimulation systems in stroke rehabilitation is anticipated.

Identification of exhaust stack sampling location of a research reactor considering ANSI/HPS N13.1-2011 mixing criteria using computational fluid dynamics

ABSTRACT Research Reactors have exhaust stacks that emit filtered radioactive gaseous waste into the atmosphere. In this research work, to check whether the radioactive gaseous waste met the requirements of ANSI/HPS N13.1–2011 mixing criteria, computational fluid dynamics (CFD) analysis was performed. According to ANSI criteria, Coefficient of Variance (COV) of velocity uniformity, flow angle, tracer gas, and aerosol particles concentration should be less than 20%. Therefore, the COV of the four parameters at different sampling positions along the stack height, with eight tracer gas and eight particles injection cases, were analyzed. The COV of velocity at 6 m height is 17.5% and flow cyclone is 9.8 degree. The results indicated that the 6 m height of the stack is enough for cyclone angle and COV of velocity to fulfill the ANSI mixing criteria. The COV of tracer gas concentration in one to eight injection cases is 10%, 4.8%, 7.5%, 17%, 2.5%, 6%, 13%, and 5% at 14 m stack height so the tracer gas also satisfied the standard mixing criteria in a concise length of 14 m because of the minimal difference in densities of tracer gas and air. However, due to their much higher density, aerosol particles took much longer to mix into the air. At 60 m stack height, the COV of aerosol particle concentration in one to eight injection cases is 14.8%, 18%, 8%, 12%, 11%, 15%, 15.5%, and 2%, respectively. As a result, when the stack height is set to 60 m, the COV of velocity, cyclone flow angle, tracer gas concentration, and aerosol particle concentration are found to meet the ANSI mixing criteria. Therefore, the minimum recommended height of the stack is proposed to be 60 m for the case under consideration.

Monitoring of Levee Deformation for Urban Flood Risk Management Using Airborne 3D Point Clouds

In the low-lying, river-rich Pearl River Delta in South China, an extensive network of flood defense levees, spanning over 4400 km, plays a crucial role in urban flood management. These levees are designed to withstand floods and storm surges, yet their failure can lead to significant human and economic losses, highlighting the need for robust urban flood defense strategies. This necessitates the development of a sophisticated geographic information system for the levee network and rapid, accurate assessment methods for levee conditions to support water management and flood mitigation efforts. This study focuses on the levees along the Hengmen waterway in the Pearl River Delta, utilizing airborne Light Detection and Ranging (LiDAR) technology to gather 3D spatial data of the levees. Employing the Cloth Simulation Filter (CSF) algorithm, non-ground point cloud data were extracted. The study improved upon the region-growing algorithm, using a seed point set approach for the automatic extraction of levee point cloud data. The accuracy and completeness of levee extraction were evaluated using the quality index. This method achieved effective extraction of four levee types, showing significant improvements over traditional algorithms, with extraction quality ranging from 72% to 83%. Key research outcomes include the development of a novel method for detecting localized levee depressions based on the computation of the variance of angles between normal vectors in single-phase levee point cloud data. An adaptive optimal neighborhood approach was utilized to accurately determine the normal vectors, effectively representing the local morphology of the levee point clouds. Applied in three levee depression detection experiments, this method proved effective, demonstrating the capability of single-phase data in identifying regions of levee depression deformation. This advancement in levee monitoring technology marks a significant step forward in enhancing urban flood defense capabilities in regions such as the cities of the Pearl River Delta in China.

(396) Comparing Phone Based 3D Scanning App to In-Office Measurements to Assess Peyronie's Deformity

Abstract Introduction Peyronie’s disease can lead to complex deformity of the penis. Three-dimensional scanning applications available on personal phones like PD Scan from endo pharmaceuticals offer the possibility of better capturing the condition in the privacy of one’s own home and track progress over time. While the application carries a disclaimer of not being FDA approved to diagnose or treat any condition, it may prove to be a useful tool to facilitate communication between the clinician and patient. Objective We sought to evaluate the differences between 3D scans captured on the PD Scan app and office measurements done by a urologist using a goniometer. Methods This study obtained measurements using: (1) a bench-top model penis bent to represent various angles and (2) real patients who were offered to monitor progress through xialfex injections. Goniometer measurements were made by a single urologist and compared to PD Scan measurements. Patients also evaluated ease of use of the app on a lichert-scale of 1-5. Results 26 measurements were obtained comparing urologist obtained goniometer measurements and PD scan software. 10 measurements were patient-generated (4 patients) and 16 measurements were from bench-top model. Primary angle variance range was +/- 15.4 degrees. Patient measurements tended to exceed urologist obtained goniometer measurements (mean difference +9 degrees). Bench model had less variance (mean difference -5 degrees). Patients overall found the app somewhat difficult to use rating it 2/5. We found PD scan useful to better document hourglass deformity and volume loss. Conclusions PD scan software in patient hands tended to overestimate penile angulation compared to office measurements with a goniometer. When used on a bench model, the 3D scan accuracy improved suggesting a user induced variance. This can have implications for tracking progress through xiaflex treatment cycles. Disclosure No.

Kinematic synergy of speed reduction during stair descent

Purpose This study aimed to quantify multi-segmental coordination using Uncontrolled Manifold (UCM) analysis to examine the effect of speed reduction on the control of stair descent. Methods Twenty healthy participants performed stair descent at a self-comfortable pace for normal speed conditions, and at a slow speed set to a metronome rhythm of 60 beats/min. UCM analysis was separately conducted for the COM and swing foot, with anteroposterior and vertical movements designated as task variables, and segment angles defined as elemental variables. ΔV, the normalized difference between the variance in segment angle that does not affect task performance (VUCM) and the variance that does affect task performance (VORT) was calculated separately for the COM and swing foot and compared between normal and slow speeds. Results The VORT for the COM and the swing foot in the anteroposterior direction were significantly lower at slow speeds than at normal speeds. The VORT of task-relevant segment angles affecting COM control in the vertical direction was significantly higher at slow speed compared to normal speed. Additionally, the ΔV in segment angle variance impacting swing foot control in the anteroposterior direction was significantly greater at slow speed than at normal speed. Conclusions The findings suggest that descending stairs at reduced speed promotes enhanced coordination of lower limb segments for controlling the swing foot in the anteroposterior direction, while concurrently increasing segmental variability that destabilizes the vertical COM.

Promoting structural distortion to enhance the crystal field strength of Mn(II) in tetrahedral bromide for near-unity yellow emission.

Two zero-dimensional hybrid manganese bromide polymorphs ((DMAPH)2MnBr4) exhibit single-crystal to single-crystal phase transformation, accompanied by an increase in MnBr4 tetrahedral bond angle variance (σ2). This structural change leads to an emission redshift due to enhanced crystal field strength, achieving yellow emission with near-unity quantum yield, which highlights its potential for solid-state lighting applications.