3D Perspective Research Articles

ABC: Aligning binary centers for single-stage monocular 3D object detection

Precisely perceiving the environment through a 3D perspective is essential and challenging for autonomous navigation and driving. Existing techniques rely on depth from LiDAR data or disparity in stereo vision to solve the poorly presented problem of detecting far-off and occluded objects. This increases structure complexity and computation burden, especially for single-stage systems. We argue that existing well-established detectors have the intrinsic potential to detect full-scene objects, but the extrinsic capabilities are limited by the structure form and optimization. Hence, we propose a double-branch single-stage monocular 3D object detection framework that aligns binary centers of object. Structurally, we construct two symmetrical and independent detectors, respectively using different prediction manners for 3D box parameters. Functionally, two detection heads have different sensitivities for the same object due to disentangling alignment. During the training, the detection heads were trained separately to obtain specific ability and aligned to promote the convergence. At inference, predictions of two branches are filtered via depth-aware non-maximal suppression (NMS) to acquire comprehensive detection results. Extensive experiments demonstrate that the proposed method achieves the state-of-the-art performance in monocular 3D detection on the KITTI-3D benchmark.

Small black hole explosions

Small black holes are a powerful tool to explore infinite distances in moduli spaces. However, we show that in 4d theories with a scalar potential growing fast enough at infinity, it is energetically too costly for scalars to diverge at the core, and the small black hole puffs up into a regular black hole, or follows a runaway behaviour.We derive a critical exponent characterizing the occurrence or not of such small black hole explosions, both from a 4d perspective, and in the 2d theory after an S2 truncation. The latter setup allows a unified discussion of fluxes, domain walls and black holes, solving an apparent puzzle in the expression of their potentials in the 4d mathcal{N} = 2 gauged supergravity context.We discuss the realization of these ideas in 4d mathcal{N} = 2 gauged supergravities. Along the way we show that many regular black hole supergravity solutions in the literature in the latter context are incomplete, due to Freed-Witten anomalies (or duals thereof), and require the emission of strings by the black hole.From the 2d perspective, small black hole solutions correspond to dynamical cobordisms, with the core describing an end of the world brane. Small black hole explosions represent obstructions to completing the dynamical cobordism. We study the implications for the Cobordism Distance Conjecture, which states that in any theory there should exist dynamical cobordisms accessing all possible infinite distance limits in scalar field space. The realization of this principle using small black holes leads to non-trivial constraints on the 4d scalar potential of any consistent theory; in the 4d mathcal{N} = 2 context, they allow to recover from a purely bottom-up perspective, several non-trivial properties of vector moduli spaces near infinity familiar from CY3 compactifications.

Simulation of horizontal sporadic E layer movement driven by atmospheric tides

The present study aims to reveal horizontal sporadic E (Es) movements driven by atmospheric diurnal/semi-diurnal tides using a three-dimensional (3D) ionospheric model. Horizontal Es movements have been investigated since the mid-twentieth century, using a variety of 1D/2D observational techniques. However, there are no comprehensive studies that explain the different results asserted by the observations. Herein, we performed 3D Es simulations at mid- and low-latitudes. This is the first study to investigate horizontal Es movements from a 3D perspective. We found that the Es layers are constrained at the zonal-wind shear nodes above sim110 km, but transported by horizontal winds below sim110 km. The Es layers that descend with the downward tidal phases move southward. The descending Es layers move westward as they lag behind the zonal-wind shear nodes. The Es layers that stagnate at sim100 km are transported by the semi-diurnal tides. In general, the descending and stagnating Es layers do not move eastward. This is because the Es layers diffuse vertically in the eastward/northward wind region or in the early stage of formation in the eastward/southward wind region. The horizontal Es movement tendency in the simulations agreed with and provided a general explanation for previous observations.Graphic

PO-03-201 VIRTUAL REALITY-BASED METHOD FOR TEACHING COMPLEX CONGENITAL HEART DISEASE ANATOMY TO EP TRAINEES – A PILOT STUDY

Developing an accurate and detailed 3D mental model of cardiac anatomy is critical for electrophysiology (EP) trainees. This can be challenging in certain forms of palliated congenital heart disease. Surgical repair of d-TGA via a Mustard or Senning procedure requires a complex baffling technique that is particularly difficult to visualize from a 3D perspective and creates a propensity for arrhythmias. Traditional teaching methods may be sub-optimal for visualizing the interaction between the conduction system and this unusual anatomic substrate. Due to its immersive, stereoscopic nature, virtual reality (VR) may provide a better learning platform in a collaborative environment. The purpose of this pilot study is to compare the experience of a collaborative, immersive VR-based educational environment with a traditional PowerPoint (PPT) method for teaching the 3D cardiac anatomy of patients who have undergone Mustard and Senning procedures to EP trainees. In collaboration with the Visible Heart Lab at the University of Minnesota and DOPL Technologies, LLC, we created an immersive VR environment that allows remotely shared viewing, manipulation, and virtual dissection of high-resolution digital 3D models of wax-infiltrated heart specimens (d-TGA s/p Mustard and Senning procedures) that were provided by Boston Children’s Hospital. Participants viewed the environment using Oculus Quest2 head-mounted displays (Meta, Menlow Park, CA, USA). Three EP trainees were recruited for the pilot study, which entailed a traditional PPT lecture followed by an interactive viewing of the models in the VR learning environment. Participants were asked to complete a pre/post-test based on the material taught then a Likert satisfaction survey adapted from previously validated usability instruments. The study participants’ mean pre-test score was 46.7% and post-test score was 76.7%, a 64.3% improvement. They globally rated the VR learning environment favorably on the Likert satisfaction survey and reported that they would like to use the VR learning environment in both didactic lecture series and for self-directed study (Figure 1). We demonstrate the feasibility of using a remote, shared, immersive VR-based education platform for teaching EP trainees cardiac anatomy related to Mustard and Senning procedures. This learning environment was favorably received. Further efforts are needed to expand the library of CHD defects and provide additional features to the learning environment.

In-situ three-dimensional investigation on micro ductile fracture mechanism of mild steel

In this paper, in-situ micro-computed tomography (micro-CT) experiments were performed on mild steel samples under monotonic tension using X-ray microscopy. A three-dimensional (3D) visualization model was reconstructed and the characteristics of void evolution under different strain states, such as void distribution, void shape, void growth and void coalescence, were quantitatively analyzed from a 3D perspective. It is found that void growth mainly depends on the stress state, while void coalescence is controlled by the stress state and intervoid spacing. The critical intervoid spacing for void coalescence occurring at the post-necking stage was given. Two stages of void coalescence, local coalescence and global coalescence, were found during void evolution. Local void coalescence was first observed at a strain of 10.02%, well before necking, but has a negligible effect on the overall void evolution. Global void coalescence was developed after the formation of a strain localization band dominated by large coalesced voids in the necking region. The propagation of fine cracks between voids along the strain localization band leads to the formation of macroscopic ductile cracks. Overall, the micro ductile fracture of mild steel is triggered by the combined effects of multiple damage mechanisms rather than independent competition.

Geometrical properties of a generalized cone and its 2D image

The generalized cone is a simple 3D shape that is produced by sweeping a planar cross-section along a curve. Many complex and articulated 3D objects can be represented by combining generalized cones. It has been shown that generalized cones play an important role in our visual system for perceiving the shapes of these objects and recognizing them. In this study, we analyzed the geometrical properties of generalized cones and their 2D images and found that there are invariant features in the images of the generalized cones under both 2D orthographic and perspective projections that facilitate the recovery of the 3D shapes of the cones from the images. We found that the 3D translational symmetry of generalized cones can be analyzed using tools designed for 3D mirror-symmetry.

A Pedagogical Approach Using Digitalization and Heritage Building Information Modelling (HBIM) for a New Practice in Architecture and Archaeology

In the past years, architectural heritage was represented and described through 2D plans, sections, perspective drawings, pictures, and texts. But, in the last decades, with the development of digital tools such as 3D scanner laser and photogrammetry, new technologies have been introduced in the digital survey of architectural heritage and 3D modelling. In this regard, we noticed that students, architects, and archaeologists still do not use photogrammetry and lasergrammetry in their work. Some of them found those methods difficult and expensive. This paper aims to describe a methodology of digitizing architectural artefacts based on digital tools such as photogrammetry and lasergrammetry that allows representing realistic and accurate 3D models and then to explain the steps that lead to introducing photogrammetric model from Autodesk recap photo software in the Autodesk Revit software to have a Heritage Building Information Modeling (HBIM) project that is useful for architectural intervention on cultural heritage using digital platform allowing multidisciplinary collaboration in architectural projects. The field of experimentation is our teaching courses with the students at the national school of architecture and urban planning in Tunisia in different sites. The student’s results are promising in the new practice of Digital Architecture and Digital Archeology and the HBIM can be a conception aid design.

Weakly-supervised pre-training for 3D human pose estimation via perspective knowledge

Modern deep learning-based 3D pose estimation approaches require plenty of 3D pose annotations. However, existing 3D datasets lack diversity, which limits the performance of current methods and their generalization ability. Although existing methods utilize 2D pose annotations to help 3D pose estimation, they mainly focus on extracting 2D structural constraints from 2D poses, ignoring the 3D information hidden in the images. In this paper, we propose a novel method to extract weak 3D information directly from 2D images without 3D pose supervision. Firstly, we utilize 2D pose annotations and perspective prior knowledge to generate the relative depth of human joints. Then, we collect a 2D pose dataset (MCPC) and generate relative depth labels. Based on MCPC, we propose a weakly-supervised pre-training (WSP) strategy to distinguish the depth relationship between two points in an image. WSP enables the learning of the relative depth of two keypoints on lots of in-the-wild images, which is more capable of predicting depth and generalization ability for 3D human pose estimation. After fine-tuning the pose model on 3D pose datasets, WSP achieves state-of-the-art results on two widely-used benchmarks.

Human cochlear microstructures at risk of electrode insertion trauma, elucidated in 3D with contrast-enhanced microCT

Cochlear implant restores hearing loss through electrical stimulation of the hearing nerve from within the cochlea. Unfortunately, surgical implantation of this neuroprosthesis often traumatizes delicate intracochlear structures, resulting in loss of residual hearing and compromising hearing in noisy environments and appreciation of music. To avoid cochlear trauma, insertion techniques and devices have to be adjusted to the cochlear microanatomy. However, existing techniques were unable to achieve a representative visualization of the human cochlea: classical histology damages the tissues and lacks 3D perspective; standard microCT fails to resolve the cochlear soft tissues; and previously used X-ray contrast-enhancing staining agents are destructive. In this study, we overcame these limitations by performing contrast-enhanced microCT imaging (CECT) with a novel polyoxometalate staining agent Hf-WD POM. With Hf-WD POM-based CECT, we achieved nondestructive, high-resolution, simultaneous, 3D visualization of the mineralized and soft microstructures in fresh-frozen human cochleae. This enabled quantitative analysis of the true intracochlear dimensions and led to anatomical discoveries, concerning surgically-relevant microstructures: the round window membrane, the Rosenthal’s canal and the secondary spiral lamina. Furthermore, we demonstrated that Hf-WD POM-based CECT enables quantitative assessment of these structures as well as their trauma.

Revisiting the empirical particle‐fluid coupling model used in DEM‐CFD by high‐resolution DEM‐LBM‐IMB simulations: A 2D perspective

AbstractThe work investigates the applicability of the unresolved Computational Fluid Dynamics and Discrete Element Method (CFDDEM) technique based on empirical equations for fluid‐particle coupling. We first carry out a series of representative volume element simulations using the high‐resolution particle‐resolved Lattice Boltzmann method and Discrete Element Method (LBMDEM) coupled by an Immersed Moving Boundary (IMB) scheme. Then, we compare the results obtained by both LBMDEM and empirical equations used in unresolved CFDDEM with analytical solutions. It is found that the existing empirical equations used in solving fluid‐particle interactions in 2D CFDDEM fail to accurately calculate the hydrodynamic force applied to solid particles. The underlying reason is that the existing empirical models are obtained based on 3D experimental results and thus are not applicable to 2D problems. Based on the simulation results, a new drag coefficient model is then proposed. The estimated drag forces using the new model are compared favourably with the simulated ones, indicating the good performance of the proposed model.

Geometric Wheat Modeling and Quantitative Plant Architecture Analysis Using Three-Dimensional Phytomers.

The characterization, analysis, and evaluation of morphology and structure are crucial in wheat research. Quantitative and fine characterization of wheat morphology and structure from a three-dimensional (3D) perspective has great theoretical significance and application value in plant architecture identification, high light efficiency breeding, and cultivation. This study proposes a geometric modeling method of wheat plants based on the 3D phytomer concept. Specifically, 3D plant architecture parameters at the organ, phytomer, single stem, and individual plant scales were extracted based on the geometric models. Furthermore, plant architecture vector (PA) was proposed to comprehensively evaluate wheat plant architecture, including convergence index (C), leaf structure index (L), phytomer structure index (PHY), and stem structure index (S). The proposed method could quickly and efficiently achieve 3D wheat plant modeling by assembling 3D phytomers. In addition, the extracted PA quantifies the plant architecture differences in multi-scales among different cultivars, thus, realizing a shift from the traditional qualitative to quantitative analysis of plant architecture. Overall, this study promotes the application of the 3D phytomer concept to multi-tiller crops, thereby providing a theoretical and technical basis for 3D plant modeling and plant architecture quantification in wheat.

Spatially heterogeneous influence of street greenery on street-level PM2.5 pollution using mobile monitoring from a three-dimensional perspective

Greenery may be effective in mitigating particulate matter (PM) pollution. However, most previous studies have explored the effects of greenery on air quality from a two-dimensional rather than a three-dimensional (3D) perspective. In this study, a geographically weighted regression (GWR) model was constructed to explore the effect of street greenery on street-level PM2.5 concentrations using street view imagery from a 3D perspective. Mobile monitoring of PM2.5 concentrations was conducted in Wuhan. The results demonstrated that GWR is suitable for exploring street-level air quality. From a 3D perspective, street greenery strongly affects the air quality of the surrounding area within 300 m. Moreover, considering spatial nonstationarity, the negative impact of street greenery on air quality depends on the pollution and ventilation conditions. High pollution and canyon effects amplify the negative impact of street greenery on pollution dispersion. Thus, the negative effect of street greenery on air quality is sensitive to the density of second-level roads and of commercial areas, the number of intersections and the distance to rivers. Dense planting trees in these areas must be reconsidered based on the possibility of ventilation loss. These results provide insights into street-level PM2.5 pollution and can contribute to the evidence-based design of urban green infrastructure.

Structure tracking strategies in different agricultural configurations

Navigating in an off-road environment is a challenging task. Indeed, robots need to recognize and detect significant elements on the path in order to navigate and perform required tasks in these environments safely. In this paper, it is proposed to study two different structure tracking strategies, that depend on the disposition of a 2D LiDAR perception solution that allows for fulfilling different agricultural tasks. The first strategy positions the LiDAR horizontally w.r.t. to the soil which permits extracting the outer contour of the structure to be followed by taking advantage of an extended vision provided by this disposition. This allows anticipation and obstacle avoidance capabilities. The second approach positions the LiDAR inclined toward the soil, allowing the recognition of the shape of a structure of interest thanks to the 3D perspective of the environment provided by the sensor layout. The 3D perspective provides knowledge on the presence or absence of vegetation. The problem associated with accurate control for mobile robots following a structure is addressed thanks to a backstepping control. In this control strategy, the longitudinal and lateral controls are computed independently and thus the regulation of the position and the orientation of the robot are separated. It is used in order to control a 4-wheel-steered mobile robot in an experimental field. The efficiency of both approaches is then investigated through full-scale experiments in various conditions.

X-view: Non-egocentric Multi-View 3D Object Detector.

3D object detection algorithms for autonomous driving reason about 3D obstacles either from 3D birds-eye view or perspective view or both. Recent works attempt to improve the detection performance via mining and fusing from multiple egocentric views. Although the egocentric perspective view alleviates some weaknesses of the birds-eye view, the sectored grid partition becomes so coarse in the distance that the targets and surrounding context mix together, which makes the features less discriminative. In this paper, we generalize the research on 3D multi-view learning and propose a novel multi-view-based 3D detection method, named X-view, to overcome the drawbacks of the multi-view methods. Specifically, X-view breaks through the traditional limitation about the perspective view whose original point must be consistent with the 3D Cartesian coordinate. X-view is designed as a general paradigm that can be applied on almost any 3D detectors based on LiDAR with only little increment of running time, no matter it is voxel/grid-based or raw-point-based. We conduct experiments on KITTI [1] and NuScenes [2] datasets to demonstrate the robustness and effectiveness of our proposed X-view. The results show that X-view obtains consistent improvements when combined with mainstream state-of-the-art 3D methods.

Seismic attributes and static reservoir simulation applications for imaging the thin-bedded stratigraphic systems of the Lower-Cretaceous Lower Goru fluvial resources, Pakistan

• Constructed workflow is a vital case for discovery of gas-bearing fluvial stratigraphic traps. • The SRSN resolves the thin-bedded point bar sandstone deposits in the basin. • AI and thicknesses for point bars sandstone are -0.214 to -0.219 g/c.c.*m/s and 17 to 19 m. • SRSN image sedimentary facies during the sea-level rise and fall events. Fluvial depositional systems accommodate a variety of primary stratigraphic-based trapping pools (STP) such as the channelized sands (CS) and point bars (PB). When they are encased within the non-porous and compacted shales, they develop hydrocarbon-bearing reserves. However, these STP are developed during the rapidly rising sea level and very slow fall, which creates hurdles in the development of accommodation space to accumulate the thin-bedded (hydrocarbon-bearing) and coarse-grained PB. PB are the primary stratigraphic traps within the fluvial hierarchy. Therefore, they require sophisticated tools such as reflection-based impedance reservoir simulations to simulate the thickness, accommodation space, proximal and distal locations, and sealing configurations of PB from a 3D perspective. The conventional seismic amplitudes are not sufficient enough to quantitatively portray these seismic sedimentological attributes due to a lack of preserved amplitudes and tuning frequency content aimed at fluvial-dominated clastic sequences. Therefore, the ultimate goal of conducting this research work is to detect thin-beds of PB and CF aimed at accumulating and generating hydrocarbon-posture STP. These thin-bedded reservoir facies are very delicate in tuning the frequency of the sub-surface systems. They require amplitude-based seismic data interpretation tools such as amplitude-based seismic attributes and inverted reservoir simulations. These tools can image the exact thickness of the reservoir lithology and types of fluids compared to the bandlimited geometrical attributes. Generally, the inverted reservoir simulations reconstruct the reflection-based impedances for the stratigraphic reservoirs, which helps in the quantification of the sub-surface thin-bedded stratigraphic systems. Therefore, the amplitude-based seismic attributes and thin-bedded wedge static reservoir simulation (SRSN) tools in Pakistan's Indus Basin. The amalgamated root-mean-square (RMS)-based seismic amplitude and frequency highlighted a full of twist continuous meander channel with a sinuosity index (S.I) > 2.7. Strong low-frequency shadows are observed at 23 Hz magnitudes that authorize the restoration of petroleum-posture fluvial-dominated PB STP. The amplitude attenuation model using the continuous wavelet transform (CWT) showed attenuation of spectral energy below the PB. The SRSN determined a 16 m thickness of STP using a constant velocity of 3449 m/s, which pinched out in the east of the Indus Basin. The predicted physical attributes from SRSN and their cross-plots against the thickness constraint have discriminated against the dominant sedimentary facies of the fluvial system during the significant rising and negligible falling sea levels. The predicted physical parameters have enabled vigorous controls aimed at developing accommodating intervals that have stored a significant amount of hydrocarbon-bearing PB. The quantitative characterization has enhanced acoustic impedance [AI] [g/c.c.*m/s] and thickness of PB with a strong correlation coefficient of R 2 >0.93. The predicted AI [g/c.c.*m/s] and thicknesses [m] aimed at PB were -0.214 to -0.219 g/c.c.*m/s and 16 to 19 m, respectively. Therefore, the SRSN can be used as a dynamic instrument for the accurate prediction of AI [g/c.c.*m/s] and thickness for the characterization of fluvial systems. This workflow may serve as a vital example for exploring the oil and gas-bearing stratigraphic system within the Indus Basin and similar basin settings.

3D Printing in the Water Treatment Industry

The advancement of 3D printing in the past few decades propelled many ground-breaking developments in the water treatment industry. More specifically, 3D printing has the unique advantage of prototyping parts of high complexity with acute precision within a short period of time. Innovative feed spacers and membranes, which could not be fabricated using conventional methods, can now be 3D printed and evaluated in actual filtration experiments. However, there are still limitations to 3D printing such as the printing resolution, build volume and printing speed which poses some problems, especially in the fabrication of membranes. This paper presents a comprehensive and critical discussion on the 3D printed feed spacer and membrane prototypes from a 3D printing perspective.

Three-dimensional mapping reveals heterochronic development of the neuromuscular system in postnatal mouse skeletal muscles

The development of the neuromuscular system, including muscle growth and intramuscular neural development, in addition to central nervous system maturation, determines motor ability improvement. Motor development occurs asynchronously from cephalic to caudal. However, whether the structural development of different muscles is heterochronic is unclear. Here, based on the characteristics of motor behavior in postnatal mice, we examined the 3D structural features of the neuromuscular system in different muscles by combining tissue clearing with optical imaging techniques. Quantitative analyses of the structural data and related mRNA expression revealed that there was continued myofiber hyperplasia of the forelimb and hindlimb muscles until around postnatal day 3 (P3) and P6, respectively, as well as continued axonal arborization and neuromuscular junction formation until around P3 and P9, respectively; feature alterations of the cervical muscle ended at birth. Such structural heterochrony of muscles in different body parts corresponds to their motor function. Structural data on the neuromuscular system of neonatal muscles provide a 3D perspective in the understanding of the structural status during motor development.

Different approaches to test orientation of self in space: comparison of a 2D pen-and-paper test and a 3D real-world pointing task

Spatial orientation is based on a complex cortical network with input from multiple sensory systems. It is affected by training, sex and age as well as cultural and psychological factors, resulting in different individual skill levels in healthy subjects. Various neurological disorders can lead to different patterns or specific deficits of spatial orientation and navigation. Accordingly, numerous tests have been proposed to assess these abilities. Here, we compare the results of (1) a validated questionnaire-based self-estimate of orientation/navigation ability (Santa Barbara Sense of Direction Scale, SBSODS) and (2) a validated pen-and-paper two-dimensional perspective test (Perspective Taking Spatial Orientation Test, SOT) with (3) a newly developed test of finger-arm pointing performance in a 3D real-world (3D-RWPT) paradigm using a recently established pointing device. A heterogeneous group of 121 participants (mean age 56.5 ± 17.7 years, 52 females), including 16 healthy volunteers and 105 patients with different vestibular, ocular motor and degenerative brain disorders, was included in this study. A high correlation was found between 2D perspective task and 3D pointing along the horizontal (azimuth) but not along the vertical (polar) plane. Self-estimated navigation ability (SBSODS) could not reliably predict actual performance in either 2D- or 3D-tests. Clinical assessment of spatial orientation and memory should therefore include measurements of actual performance, based on a 2D pen-and-paper test or a 3D pointing task, rather than memory-based questionnaires, since solely relying on the patient’s history of self-estimated navigation ability results in misjudgments. The 3D finger-arm pointing test (3D-RWPT) reveals additional information on vertical (polar) spatial performance which goes undetected in conventional 2D pen-and-paper tests. Diseases or age-specific changes of spatial orientation in the vertical plane should not be clinically neglected. The major aim of this pilot study was to compare the practicability and capability of the three tests but not yet to prove their use for differential diagnosis. The next step will be to establish a suitable clinical bedside test for spatial memory and orientation.

Molecular Clouds as Gravitational Instabilities in Rotating Disks: A Modified Stability Criterion

Molecular gas disks are generally Toomre stable (Q T > 1) and yet clearly gravitationally unstable to structure formation as evidenced by the existence of molecular clouds and ongoing star formation. This paper adopts a 3D perspective to obtain a general picture of instabilities in flattened rotating disks, using the 3D dispersion relation to describe how disks evolve when perturbed over their vertical extents. By explicitly adding a vertical perturbation to an unperturbed equilibrium disk, stability is shown to vary with height above the midplane. Near z = 0, where the equilibrium density is roughly constant, instability takes on a Jeans-like quality, occurring on scales larger than the Jeans length and subject to a threshold Q M = κ 2/(4π G ρ) = 1 or roughly Q T ≈ 2. Far from the midplane, on the other hand, stability is pervasive, and the threshold for the total disk (out to z = ±∞) to be stabilized is lowered to Q T = 1 as a consequence. In this new framework, gas disks are able to fragment through partial 3D instability even where total 2D instability is suppressed. The growth rates of the fragments formed via 3D instability are comparable to, or faster than, Toomre instabilities. The rich structure in molecular disks on the scale of tens of parsecs can thus be viewed as a natural consequence of their 3D nature and their exposure to a variety of vertical perturbations acting on roughly a disk scale height, i.e., due to their situation within the more extended galaxy potential, participation in the disk-halo flow, and exposure to star formation feedback.

Methodology to Analyse Three-Dimensional Asymmetries in the Forces Applied to the Pedals in Cycling

The asymmetries study between both legs of the forces applied to the pedals in cycling is important because they may affect the performance of the cyclist or prevent the occurrence of injuries. Studies focused on analysing asymmetries in forces tend to consider only the effective force, disregarding the three-dimensional nature of the force. Furthermore, these studies do not analyse the possible physical or neurological causes that may have led to the appearance of the asymmetries. This paper presents a methodology to carry out three-dimensional analysis of the asymmetries of the forces applied in both pedals and discriminate the possible sources of these asymmetries. Seven participants, amateurs and without pathologies, were analysed. Two commercial pedals were instrumented to measure the three components of the force applied to each pedal. The Normalized Symmetry Index (NSI) and the Cross Correlation Coefficient (CCC) were used for the asymmetries analysis. Results showed that both indexes need to be used in conjunction to analyse the causes of asymmetry in the pedal forces from a 3D perspective along the pedal cycle. The NSI is an index that makes it possible to evaluate asymmetry by considering only the value of the force applied by each leg at each instant. The CCC makes it possible to evaluate whether the temporal evolutions of the forces applied by each leg are similar. Preliminary results suggest that the proposed methodology is effective for analysing asymmetries in the forces in a pedalling cycle from a three-dimensional point of view. Forces in the sagittal plane showed a high level of symmetry. The lateral-medial force presented the highest level of asymmetry due to the difference in the magnitudes of the applied forces by both legs and the existing time shift between the two force patterns. The results of this work will allow for more complete and accurate three-dimensional dynamic analyses of the lower body during pedalling.