Layout Geometry Research Articles

Adaptive hysteretic model for reinforced concrete columns including variations in axial force and shear span length

AbstractIn this study, a hysteretic model is developed for simulating the nonlinear response of reinforced concrete columns with strength degradation behavior under cyclic loading. During analysis, the proposed model exhibits the ability to adjust the model parameters assigned to the model continually, based on the monitored element boundary conditions. A semi‐empirical relationship between model parameters and boundary conditions is formulated from experimental evidence, which is used to adjust the model parameters. The boundary conditions that are monitored include the axial load acting on the column section and shear span length; these are known to have a significant effect on capacity in terms of strength and ductility. The developed model was implemented in the widely used research‐oriented structural analysis software, OpenSees. To simulate the nonlinear response of the columns, model parameter predictive equations composed of input parameters such as material strength, reinforcement layout, and specimen geometry were developed using lasso regression. As an application of the proposed column model, an eight‐story code‐conforming frame building was selected to perform incremental dynamic analyses based on 44 far‐field ground motions. The numerical results showed that, without the model parameter adaptation feature, the median collapse capacity and residual story drift can be significantly overestimated.

Rooms without walls: Young children draw objects but not layouts.

Drawing is the epitome of uniquely human expression, with few known limits beyond those of our perceptual and motor systems and the cultures in and for which we draw. The present study evaluates whether the drawings of young children nevertheless reveal an early emerging bias in the depiction of 2 different foundational spatial categories: layouts and objects. Across 2 experiments following preregistered designs and analysis plans, 4-year-old children either sat in a colorful "fort" or looked at a small "toy" version of the fort and were asked to draw exactly what they saw. Children's drawings often omitted the walls composing the fort's layout but included the corresponding object parts for the toy. Symbolic representations of space in young children's drawings thus privilege small-scale objects over large and fixed layout geometry. A distinction between the intuitive geometries of layouts and objects leads to their differential treatment in both humans and other animals during everyday navigation. This distinction may also underlie the differential treatment of layouts and objects in children's drawings. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

RF-Based Indoor Moving Direction Estimation Using a Single Access Point

Indoor moving direction and rotation angle measurements are crucial to many ubiquitous mobile computing applications. Most of the state-of-the-art approaches rely on inertial sensors, e.g., accelerometers, gyroscopes, and magnetometers, which suffer from severe accumulative errors or accuracy degradation indoors. This article presents an RF-based direction estimation method, which utilizes the off-the-shelf commodity WiFi devices for accurate moving direction and in-place rotation angle estimation. The proposed approach employs a novel 2-D antenna array and leverages the spatial decay property of the time-reversal resonating strength. First, the moving speeds along different directions, specified by the 2-D array, are derived using virtual antenna alignment. The precise estimation of the device’s moving direction is then achieved by combining the obtained velocity information and the a prior knowledge of the array’s geometry layout. Experiments in a multipath-rich indoor environment have shown that the median error for moving direction estimation is 6.9°, which outperforms the accelerometer counterpart. The results also verify the good accuracy of in-place rotation angle estimation without any accumulative error, which beats the gyroscope in long-term tests. Because the proposed approach can achieve high accuracy without accumulative drifts, it is a promising candidate solution to applications that require accurate direction information.

A Scaling Law for SPAD Pixel Miniaturization.

The growing demands on compact and high-definition single-photon avalanche diode (SPAD) arrays have motivated researchers to explore pixel miniaturization techniques to achieve sub-10 μm pixels. The scaling of the SPAD pixel size has an impact on key performance metrics, and it is, thereby, critical to conduct a systematic analysis of the underlying tradeoffs in miniaturized SPADs. On the basis of the general assumptions and constraints for layout geometry, we performed an analytical formulation of the scaling laws for the key metrics, such as the fill factor (FF), photon detection probability (PDP), dark count rate (DCR), correlated noise, and power consumption. Numerical calculations for various parameter sets indicated that some of the metrics, such as the DCR and power consumption, were improved by pixel miniaturization, whereas other metrics, such as the FF and PDP, were degraded. Comparison of the theoretically estimated scaling trends with previously published experimental results suggests that the scaling law analysis is in good agreement with practical SPAD devices. Our scaling law analysis could provide a useful tool to conduct a detailed performance comparison between various process, device, and layout configurations, which is essential for pushing the limit of SPAD pixel miniaturization toward sub-2 μm-pitch SPADs.

Methodological and On-Site Applied Construction Layout Plan with Batter Boards Stake-Out Methods Comparison: A Case Study of Romania

The layout or stake-out is one of the most important assignments of the surveying engineer, and it is of vital importance in the building process, as the designed geometries of the structure ensure the verticality and the correct positioning inside the terrain. The mission of the surveying engineer involves both legal and technical aspects, and the correct planning of the layout process must take into consideration aspects regarding the site conditions, instrumentation used, the required and achievable accuracies, network design and survey methods used. Given the vast applications of geodesy and topography in different domains and industries, the study incorporates general notions and technical aspects regarding the workflow in cadastre and construction surveying, guidelines for an efficient design of site layout plan with on-site applicability, as well as a novel comparison between four methods of construction lines geometry layout on batter boards. The results of this study aim to further consolidate the importance of accurate and efficient construction layout projects, with comprehensive design plans, methods and instrumentation selection, as well as recommendations. The presented discussions and conclusions are of interest to the geodetic community as well as the construction industry, and due to the pragmatic and experimental nature of the research, incorporates technical notes and original results of professional and academic importance.

Robotic coreless filament winding for hyperboloid tubular composite components in construction

Novel fabrication methods are necessary to capitalize on the high strength-to-weight ratio of composites engineered for construction applications. This paper presents prefabrication strategies for geometrically-complex building elements wound out of Glass and Carbon Fiber Reinforced Polymers (G/CFRP). The research focuses on Robotic Coreless Filament Winding (RCFW), a technology that eliminates formwork, proposing upscaling and industrialization strategies combined with updated robot programming and control methods. Our application addresses the prefabrication of hyperboloid, tubular components with differentiated geometry and fiber layout. We examine how the proposed methods enabled the industrial prefabrication of a building-scale G/CFRP dome structure and discuss the industrial process relative to key fabrication parameters. Highlighting the interdisciplinary nature of the research, we envisage future directions and applications for RCFW in construction. Overall, we find that synergy between academia and industry is essential to meeting research, productivity, and certification goals in the rather conservative building industry.

The Effect of Modifying Double Continuous Flow Intersections Layout Geometric Features on their Operation

Introduction: Continuous flow interventions were first introduced as an alternative to improve traffic operations in the intersections with severe congestion caused by heavy left-turn movements. Objective: This study quantified the effect of modifying the intersection angles of Double Continuous Flow Intersections (DCFI) on their operational characteristics. Mainly, the effects of changing the intersection angle between the different approaches of the main intersection and the angle of the minor cross-over intersections were investigated. Methods: VISSIM software simulation models were used for modifying several design features related to the DCFI and the operational performance was compared between the different simulation scenarios. Results and Discussion: Changes to the cross-over intersection angle increase the safety levels by providing better channelization of traffic movements on the minor intersections of the DCFI and reduce the intersection footprint to be used at high-density urban locations. Increasing the cross-over intersection angle and changing the layout geometry have adverse effects on the capacity of the conventional DCFI. This is mainly because of the added curvature in the intersection approaches which reduces the vehicle speeds, therefore reducing the overall capacity of the modified intersection when compared to the conventional DCFI. However, the total footprint for the intersection is reduced for the modified layout geometry, which improves the capacity of the DCFI. Conclusion: The study has explored the effects of modifying the DCFI intersection angles to fit the limited space in major urban areas on the capacity and performance of the intersection. It showed that DCFI designs could be applied in areas with limited space availability and skewed intersection angles.

Comparison between Specialized Quadrature Rules for Method of Moments with NURBS Modelling Applied to Periodic Multilayer Structures

A comparison between Ma-Rokhlin-Wandzura (MRW) and double exponential (DE) quadrature rules for numerical integration of method of moments (MoM) matrix entries with singular behavior is presented for multilayer periodic structures. Non Uniform Rational B-Splines (NURBS) modelling of the layout surfaces is implemented to provide high-order description of the geometry. The comparison is carried out in order to show that quadrature rule is more suitable for MoM matrix computation in terms of sampling, accuracy of computation of MoM matrix, and CPU time consumption. The comparison of CPU time consumption shows that the numerical integration with MRW samples is roughly 15 times faster than that numerical integration using DE samples for results with similar accuracies. These promising results encourage to carry out a comparison with results obtained in previous works where a specialized approach for the specific analysis of split rings geometries was carried out. This previous approach uses spectral MoM version with specific entire domain basis function with edge singularities defined on split ring geometry. Thus, the previous approach provides accurate results with low CPU time consumption to be compared. The comparison shows that CPU time consumption obtained by MRW samples is similar to the CPU time consumption required by the previous work of specific analysis of split rings geometries. The fact that similar CPU time consumptions are obtained by MRW quadrature rules for modelling of general planar geometries and by the specialized approach for split ring geometry provides an assessment for the usage of the MRW quadrature rules and NURBS modelling. This fact provides an efficient tool for analysis of reflectarray elements with general planar layout geometries, which is suitable for reflectarray designs under local periodicity assumption where a huge number of periodic multilayer structures have to be analyzed.

Deep relightable textures

The increasing demand for 3D content in augmented and virtual reality has motivated the development of volumetric performance capture systemsnsuch as the Light Stage. Recent advances are pushing free viewpoint relightable videos of dynamic human performances closer to photorealistic quality. However, despite significant efforts, these sophisticated systems are limited by reconstruction and rendering algorithms which do not fully model complex 3D structures and higher order light transport effects such as global illumination and sub-surface scattering. In this paper, we propose a system that combines traditional geometric pipelines with a neural rendering scheme to generate photorealistic renderings of dynamic performances under desired viewpoint and lighting. Our system leverages deep neural networks that model the classical rendering process to learn implicit features that represent the view-dependent appearance of the subject independent of the geometry layout, allowing for generalization to unseen subject poses and even novel subject identity. Detailed experiments and comparisons demonstrate the efficacy and versatility of our method to generate high-quality results, significantly outperforming the existing state-of-the-art solutions.

An experimental and numerical study of feasibility of a novel technology to manufacture hot stamping dies with pre-constructed tube network

The cooling system is a critical element in tooling for hot stamping high-strength aluminium alloys, for which very high quenching rates are required to ensure a supersaturated solid solution state in formed parts. To enhance cooling, ducts within the tools should be close and conformal to the surface die profile. Currently, ducts with curved profiles are made by drilling short straight lengths in die segments which are clamped together to form a complete die, which is expensive and hard to achieve the shape of duct with best cooling performance. To address these disadvantages, a novel method which enables efficient manufacture of conformal cooling systems by embedding a network of tubular cooling ducts within a cast matrix is presented in this paper. The feasibility of the proposed method of making ducts in the hot stamping die is demonstrated. Both experimental and computer-based die quenching tests using heated aluminium test pieces were undertaken to determine the cooling performance of a laboratory-scale tool set with cooling ducts. Simulations using the validated FE model were performed to investigate the effects of cross-sectional geometry, material and duct layout, on the quenching performance of the tools. It was found that ducts made of mild steel perform sufficiently well to make the use of high conductivity copper unnecessary. For a flat die surface, square section ducts provided highest cooling rates in comparison with circular and diagonal ones. The uniformity of die temperature increases with the decreased distance between neighbouring ducts, which indicates that a minimal gap is recommended without deteriorating tool strength. The developed tooling technology has the potential to provide a low-cost, highly efficient method of making conformal cooling ducts because the hot stamping die of high-strength aluminium alloy panels requires larger dimension, greater complexity and higher quenching rates.

Insights into the Relationships Among the Roof, Rib, Floor, and Pillars of Underground Coal Mines

Ground control failures continue to be one of the leading causes of injuries and fatalities in underground coal mining. The roof, rib, floor, and pillars are four areas of potential ground failures that miners, engineers, and consultants are continually evaluating. Quite often, these four underground structures are evaluated independently. A recent push to consider them as a system and in a similar manner as design engineers evaluate mechanical systems has highlighted the need to fully understand the interrelationship among the roof, rib, floor, and pillar. This relationship combines the geometry of the mine layout, geological environment, installed support, and even the timing of the coal extraction. Several studies using field observations and instrumentation show that these relationships can be independent at times, while being dependent in other scenarios. Cases with good roof conditions while the rib and floor deteriorate are contrasted with cases where the roof, rib, and floor deteriorate at the same time. The presented cases in this study demonstrate the importance of understanding the geological environment and mine design to ensure that the proper support is installed.

BICGSTAB-FFT Method of Moments with NURBS for Analysis of Planar Generic Layouts Embedded in Large Multilayer Structures

BICGSTAB-FFT method of moment (MM) scheme is proposed to analyze several levels of planar generic layouts embedded in large multilayer structures when the layout geometries are modeled by NURBS surfaces. In this scheme, efficient computation of normalized error defined in iterative bi-conjugate gradient stabilized (BICGSTAB) method for large multilayer structure analysis problems is implemented. The efficient computation is based on pulse expansion with dense equi-spaced mesh of generalized rooftop basis functions (BFs) defined on NURBS surfaces and equivalent periodic problem (EPP) in order to apply fast Fourier transforms (FFT). Moreover, efficient computation of Green’s functions for multilayer structure is implemented for near and far field regions. Experimental and numerical validations of whole printed reflect array antennas of electrical size between 8 and 16 times the vacuum wavelengths are shown. In these validations, CPU time consumptions of the proposed method are obtained with results between few minutes and half an hour using a conventional laptop.

PARTICIPATORY IMAGE-BASED MODELS’ ALIGNMENT FOR RECONSTRUCTING A LARGE-SCALE INDOOR MAPPING

Abstract. In this paper, we introduced a recently developed image-based model alignment technique for 3D reconstruction of large-scale indoor corridors. The proposed participatory model alignment technique enables crowd source single image-based modeling since it allows various participants to incorporate their images taken from different cameras for large-scale indoor mapping. This technique is robust against changes of camera orientation and prevents miss-association of a newly generated 3D model to the previously integrated models. To investigate the possibility of aligning two individual 3D models, their respective corridor topological graphs must match, and they need to geometrically transform into the same object space. Here 3D affine transformation is applied, and the transformation parameters are estimated through corresponding vertices of both 3D models. Having integrated two models in the same 3D space, they will be back projected into the image space for evaluation using Direct Linear Transformation. Note that the proposed method performs layout model matching in image space and considers information including layout topology and geometry as well as image information to address model alignment. The advantages of using layout information in the proposed alignment technique are twofold. First, a metric constraint is imposed to insure topological model consistency and balance 3D models scale issues. Second, it will reduce alignment ambiguity related to indoor corridor scenes, where the scene is enriched with multiple structural elements including various corridors junctions. To evaluate the performance of the proposed method, we have performed the experiments on a data set collected from Ross building corridors at York University. This dataset includes single images captured by a handheld wide-angle camera. The obtained results present the ability of the proposed method in alignment of single image-based 3D models while producing limited geometric errors.

A Linear Programming Method for Finding a Minimal Set of Axial Lines Representing an Entire Geometry of Building and Urban Layout

This paper devises an algorithm for finding the minimal set of axial lines that can represent a geometry of building and urban layout in two dimensions. Although axial lines are useful to analyze spatial configuration in the Space Syntax, existing methods for selecting axial lines seldom address the optimality of their solutions. The proposed algorithm uses linear programming to obtain a minimal set of axial lines. To minimize the number of axial lines that represent the entire geometry of building and urban layout, a linear programming problem is established in which a set of axial lines represents the entire geometry. The axial lines must have at least one intersection with every extension line of the wall edges to the sides of the reflex angles. If a solution to this linear programming problem exists, it will be guaranteed to be an optimum. However, some solutions of this general linear programming problem may include isolated lines, which are undesirable for an axial line analysis. To avoid isolated axial lines, this paper states a new formulation by adding a group of constraints to the original formulation. By examining the modified linear programming problem in various two-dimensional building maps and spatial layouts, this paper demonstrates that the proposed algorithm can guarantee a minimum set of axial lines to represent a two-dimensional geometry. This modified linear programming problem prevents isolated axial lines in the process of axial line reduction.

An Optimization Approach for Stiffener Layout of Composite Stiffened Panels Based on Moving Morphable Components (MMCs)

An explicit topology optimization method for the stiffener layout of composite stiffened panels is proposed based on moving morphable components (MMCs). The skin and stiffeners are considered as panels with different bending stiffnesses, with the use of equivalent stiffness method. Then the location and geometric properties of composite stiffeners are determined by several MMCs to perform topology optimization, which can greatly simplify the finite element model. With the objective of maximizing structural stiffness, several typical cases with various loading and boundary conditions are selected as numerical examples to demonstrate the proposed method. The numerical examples illustrate that the proposed method can provide clear stiffener layout and explicit geometry information, which is not limited within the framework of parameter and size optimization. The mechanical properties of composite stiffened panels can be fully enhanced.

Database on seismic response of instrumented flood control levees

We present a database documenting the seismic response of seven instrumented flood control levee segments in Japan. The database includes (1) maps and cross-sections showing levee geometry and instrument layouts; (2) ground motion time series, and (where available) piezometric recordings; (3) reported field performance from post-earthquake reconnaissance (i.e. permanent displacements, other evidence of ground failure); and (4) geotechnical data, including geologic cross-sections, stratigraphy, penetration resistance, and shear wave velocity ( VS) profiles. The data are complete with respect to these attributes for three sites, with geotechnical data and field performance data missing for two and four sites, respectively. The database contains 150 recordings from 25 events and can be accessed through DOI: 10.21222/C2TC95. Ground motions were processed using standard procedures for Next Generation Attenuation projects. We present example data for a segment damaged by the M9.1 2011 Tohoku-oki earthquake, which includes ground motion and pore water pressure measurements.

The instrument suite of the European Spallation Source

An overview is provided of the 15 neutron beam instruments making up the initial instrument suite of the European Spallation Source (ESS), and being made available to the neutron user community. The ESS neutron source consists of a high-power accelerator and target station, providing a unique long-pulse time structure of slow neutrons. The design considerations behind the time structure, moderator geometry and instrument layout are presented.The 15-instrument suite consists of two small-angle instruments, two reflectometers, an imaging beamline, two single-crystal diffractometers; one for macromolecular crystallography and one for magnetism, two powder diffractometers, and an engineering diffractometer, as well as an array of five inelastic instruments comprising two chopper spectrometers, an inverse-geometry single-crystal excitations spectrometer, an instrument for vibrational spectroscopy and a high-resolution backscattering spectrometer. The conceptual design, performance and scientific drivers of each of these instruments are described.All of the instruments are designed to provide breakthrough new scientific capability, not currently available at existing facilities, building on the inherent strengths of the ESS long-pulse neutron source of high flux, flexible resolution and large bandwidth. Each of them is predicted to provide world-leading performance at an accelerator power of 2 MW. This technical capability translates into a very broad range of scientific capabilities. The composition of the instrument suite has been chosen to maximise the breadth and depth of the scientific impact of the early years of the ESS, and provide a solid base for completion and further expansion of the facility.

90% <i>SNR</i> Improvement with Multi-Port Hall Plates

For Hall plates, the ratio of signal over thermal noise is determined by material properties, thickness, layout geometry, magnetic field, and the electric power at which the plate is operated. For traditional Hall plates with four contacts, the optimum choice is a symmetrical device with medium-sized contacts. This paper shows that the signal-to-noise-ratio (SNR) can be further increased by up to 90% for Hall plates with more than four contacts. Supply currents flow through several pairs of contacts, while a signal conditioning circuit taps output voltages at all pairs of contacts and sums them up. We compute the total thermal noise of the sum of correlated noise voltages and relate it to the total magnetic sensitivity. We also prove that for electrically linear devices a spinning current scheme cancels out zero point errors (offset errors) in a strict sense. All our investigations use the definite resistance matrix of multi-port Hall plates. We develop an analytical theory based on recent advances in the theory of Hall plates, and then we compute the integrals and matrices numerically for symmetrical Hall plates with six to 40 contacts. We also present measurements in accordance with our theory.

3D Printed Low-Cost Force-Torque Sensors

Force sensing is essential for many manipulation tasks and, more generally, for all robots physically interacting with their environment. While multi-axis force/torque sensors are readily available commercially, their cost and complex integration have so far limited a wide deployment. In this paper, we introduce a modular approach to design and to integrate low-cost force sensors directly into 3D printed robot parts. Based on off-the-shelf optical sensors embedded into deformable structures, sensitivity and load capacity can be selected from a wide range. A working six-axis sensor, including electronics, can be built for less than 20 dollars, plus a few hours of 3D printing. We present tested example designs for sensors of different complexity, from a basic one-dimensional deflecting beam to six-axis sensors with custom shapes. We summarize the basic sensor layout geometries, explain key 3D printing and integration aspects, discuss sensor calibration, and describe our Arduino firmware and ROS-based drivers.

Turbulent-Resistance Model for Organized Rough Walls

A resistance model for organized rough walls of varying geometry in fully-developed turbulent boundary layers is proposed. For a given flow, the shear stress on rough walls varies with the surface geometry. The model normalizes the roughness shear stress by its theoretical maximum. Based on an analysis of measurable drag on individual roughness elements, the expression for the normalized roughness shear stress is deduced and expressed as a simple function of the roughness density with one empirical coefficient, which varies with the element geometry and array layout. Two reduction mechanisms for the drag on the roughness elements are distinguished, and three types of rough walls are categorized according to the effective ranges of the physical mechanisms. The resistance model is validated by comparison with existing measurements. The directly and indirectly measured drag on roughness elements from classical laboratory experiments and recent simulations are reproduced by this model, providing a convenient method for comparing distinctive experiments and simulations, which is important for the categorization of organized rough walls and the formulation of a unified roughness model.