Geometric Shape Research Articles

Non-Rigid Registration Via Intelligent Adaptive Feedback Control.

Preserving features or local shape characteristics of a mesh using conventional non-rigid registration methods is always difficult, as the preservation and deformation are competing with each other. The challenge is to find a balance between these two terms in the process of the registration, especially in presence of artefacts in the mesh. We present a non-rigid Iterative Closest Points (ICP) algorithm which addresses the challenge as a control problem. An adaptive feedback control scheme with global asymptotic stability is derived to control the stiffness ratio for maximum feature preservation and minimum mesh quality loss during the registration process. A cost function is formulated with the distance term and the stiffness term where the initial stiffness ratio value is defined by an Adaptive Neuro-Fuzzy Inference System (ANFIS)-based predictor regarding the source mesh and the target mesh topology, and the distance between the correspondences. During the registration process, the stiffness ratio of each vertex is continuously adjusted by the intrinsic information, represented by shape descriptors, of the surrounding surface as well as the steps in the registration process. Besides, the estimated process-dependent stiffness ratios are used as dynamic weights for establishing the correspondences in each step of the registration. Experiments on simple geometric shapes as well as 3D scanning datasets indicated that the proposed approach outperforms current methodologies, especially for the regions where features are not eminent and/or there exist interferences between/among features, due to its ability to embed the inherent properties of the surface in the process of the mesh registration.

Three-dimensional trajectories of irregular-shaped tunnel lining fragments in the flow environment caused by high-speed trains

High-speed railway tunnel lining fragments can cause collisions with trains and track blockages, severely affecting train operation. When a train passes through a tunnel where lining fragment is likely to occur, the train wind effect may significantly affect the trajectory of the lining fragment, making the location where the lining fragment is difficult to predict. For safety purpose, this study aims to analyze the impact of the initial circumferential position and shape of irregular-shaped lining fragments on their aerodynamic performance. Using on-site scanning and mathematical statistical methods, the shape characteristics and probability distribution of actual lining fragments in the tunnel are obtained. The aerodynamic behavior of irregular-shaped lining fragments with different initial positions and three typical aspect ratios (ARs) are investigated based on the overset grid method and the dynamic fluid–body interaction model framework as a high-speed train passes. The study found that the most representative lining fragments with an AR of three have a mass of 1.5 kg and are located 2.5 m from the tunnel centerline. The flight behavior of lining fragments shows distinct three-dimensional features, with both translation and rotation significantly affected by the aerodynamic effects of the train and the geometric shape of the fragments. The longitudinal and lateral translational distances of lining fragments at the top of the train decrease as their initial position moves further from the tunnel's centerline. With an increase in AR, both the longitudinal and lateral flight distances and average flight velocities of the fragments increase. The macroscopic flow field within the tunnel directly influences the motion characteristics of the lining fragments. Complex flow separation and circulation phenomena near the fragments result in uneven pressure differences acting on the smooth and rough surfaces of the lining fragments, causing irregular motion. The conclusions of this study provide a theoretical basis for assessing and preventing the impact of lining fragments on the operational safety of trains.

Rated flow coefficient of geometric compensation control valve

Abstract Aiming at the large design error of the rated flow coefficient of existing control valves, it was difficult to meet the requirements of the equipment system. This study adopts the principle of infinite approximation to the existing flow coefficient calculation equation for geometric shape correction compensation, based on which the rated flow coefficient design method was proposed, and simulation and test verification were carried out. The results show that according to the design method, the rated flow coefficient of the control valve can be accurately designed. The variation rule of the simulated value and the test value under the two kinds of spool inner parts is consistent, and the maximum error is not more than 10%, which meets the requirements of industrial standards. The experiment verifies the accuracy and applicability of the design method.

Joint Optimization of Probabilistic Shaping and Geometric Shaping for Faster-than-Nyquist Signaling

Abstract We propose a joint optimization algorithm of probabilistic shaping and geometric shaping for faster-than-Nyquist (FTN) signaling. The theoretical analysis and bit error performance both represent that the FTN probabilistic-geometric shaping method is superior to the conventional Nyquist regular QAM system. When spectral efficiency (SE) is 3.077 bits/s/Hz, the proposed 16QAM FTN probabilistic-geometric shaping scheme can obtain 1.65 dB theoretical gain compared to the conventional Nyquist regular 16QAM system, while the simulation gain is 2.90 dB with spectral efficiency at 3.077 bits/s/Hz. The proposed 16QAM FTN probabilistic-geometric shaping scheme can obtain 1.63 dB theoretical gain compared to the conventional FTN regular 16QAM system, while the simulation gain is 3.28 dB with spectral efficiency at 3.282 bits/s/Hz. Therefore, the proposed method is reliable, which can be regarded as a potential scheme for the 6G communications.

Connecting the aesthetics of abstract art of geometric shapes to modern architecture "Formation of architectural blocks and urban spaces"

Connecting the aesthetics of abstract art of geometric shapes to modern architecture "Formation of architectural blocks and urban spaces"

A review on microstrip patch antenna for wireless communication systems at 3.5 GHz

This article presents a review of several microstrip patch antennas for 3.5 GHz wireless applications. Different substrate materials, FR-4 (loss), FR-4 Epoxy, Rogers RT/droid 5880, TLC-30, and Rogers RT/droid 5880 LZ, are used. In recent years, wireless antenna applications have increased, including biomedical appliances, internet of things (IoT) terminals, edge devices, radars, mobile phones, and many more. In this work, several articles were reviewed and investigated, and several microstrip patch antennas with a resonance frequency of 3.5 GHz were designed using different substrate materials and shapes. This article also discussed the geometric shapes of antennas, antenna properties, sizes of substrate materials, loss tangent, thickness, return loss, bandwidth, voltage standing wave ratio (VSWR), gain, efficiency, and directivity. Several software is used for design and simulation, including computer simulation technology (CST), high-frequency simulation frequency (HFSS), and advanced design system (ADS), FEKO, and MATLAB. The main goal of this paper is to talk about different wireless application papers that work in the S-band at a frequency of 3.5 GHz and have been published in various international journals and conferences.

Application and Effectiveness of Virtual Reality in Teaching Basic Concepts to Children with Autism Spectrum Disorder

Background: This study compares traditional teaching methods with cutting-edge virtual reality (VR) technology to assess its effectiveness in teaching basic concepts to children with autism spectrum disorder (ASD). Methods: Thirty-two children with ASD were included in the study and randomly assigned to either the VR or the control group. For the VR group, a teaching material was developed as an easy-to-play VR game called Geometry Park to teach concepts of shapes and colors to children with ASD, by virtually traveling through a world filled with geometrical shapes in different colors and sizes. For the control group, similar teaching material was prepared using flashcards with shapes and colors similar to those in Geometry Park. Each subject underwent ten play-and-learn sessions. At the end of the sessions, the research assistant asked them to identify 23 shapes and colors using "test flash cards" and reported the scores for each item. Results: The result of the two-sample t-test did not show a statistically significant difference between the means of the two groups (P=0.45), which might be a false negative due to Type II error. However, a medium effect size was observed for the VR group compared to the control group (Cohen’s d=0.39). Conclusion: The results of this experiment did not demonstrate a statistically significant difference between the VR and the control groups. However, a medium effect size was found for the VR group, which is "clinically significant".

SPATIO-TEMPORAL ANALYSIS OF CHANGES IN ECOSYSTEMS OF MUNICIPAL WASTE LOCALISATION AREAS USING GIS AND REMOTE SENSING DATA

The Zdovbytsia municipal solid waste (MSW) dump (the Rivne region, Ukraine) as a case study allows demonstrating informativeness of identifying waste dump sites and the adjusted areas using the spectral characteristics and texture of earth’s covers obtained from the satellite images for the different years. To identify the MSW dump in the surveyed area, direct coding features were considered, which characterized the properties of the object and are directly represented in the images. These are such features as geometric (shape, shadow, size), brightness (phototone, brightness level, color, spectral image), structural (texture, structure) ones. In addition, satellite images reliably identified the presence of discharging from the dump area, their directions, areas of unloading, the damage to herbaceous cover and other vegetation, etc. The informativeness of the study of dynamics for dump geometrical parameters, the change of its internal “structure,” the functional changes in the surrounding ecosystem elements (first, the changes in the forest stands and agricultural lands) is demonstrated. In particular, satellite image data for the period of 2003 to 2021 allow identifying the increase in a number of the Zdovbytsia MSW dump sites at the expense of adjacent forest stands. Thus, in 2003 one site of the dump is operated, whereas in 2019—already three ones, that integrated in 2021. The study of dynamics for the change of the total area of dump has revealed the increase of this area by approximately 6.25 times (from 6 521 m2 in 2003 to 20 438 m2 in 2021). In addition, the total perimeter along the contours of its stages has enlarged more than 3.35 times (from 438 to 1 466 m, respectively). The use of satellite images of higher spatial resolution in the area of about 0.6 m/pixel will specify the cases of unsatisfactory condition of the dump.

Structural and Optical Properties of Activated Carbon Derived from Eggshell

This research was done to prepare the eggshell as activated carbon (AC) using the simple chemical activation process. Phosphoric acid (H3PO4) at different molarities of 0.50, 0.75 and 1.00 M is used as an activation agent. All samples were analysed and characterized by using X-ray diffraction (XRD), scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). SEM images show irregular shapes of carbon. XRD patterns of AC were observed at 29.7°, 36.2°, 40.5°, 43.5°, 47.7° and 48.7° which corresponds to Braggs reflection planes of (201), (105), (107), (207), (206) and (304) respectively. The obtained diffraction peaks show the hexagonal crystal structure of carbon and are well matched with standard JCPDS: 721-616. SEM images show that the structure of AC are fake-like structures and exhibit partial geometrical shape when synthesized at 0.50 M. A broad and strong peak is observed at 1400 centimeter and a sharp peak appears at 872 centimeter due to stretching and bending vibration of the carbonate group present in the samples. The band observed at 1071 centimeter corresponds to the vibration of the phosphate group.

EKSPLORASI ETNOMATEMATIKA PADA KERAJINAN CAPING DI DAERAH KABUBATEN KAMPAR

Mathematical concepts are often used in everyday life. The term that refers to mathematical concepts in cultural concepts is ethnomathematics. Ethnomathematics is a science used to understand how mathematics is adapted from a culture. This research discusses the exploration of ethnomathematics contained in the process of making Caping crafts in Kampar Regency. This research aims to explore the ethnomathematics concept found in Caping crafts in Kampar Regency. This type of research is qualitative with data collection obtained from observation, documentation and interviews related to Caping crafts in Kampar Regency. The results of the research show that: The mathematical concept that exists in the Caping making process is the geometry of flat shapes, namely equilateral triangles, circles and rectangles. The geometric shape of a space is a cone. Transformation geometry is reflection.

The Influence of Contemporary Architecture on The Shape of Library Buildings and Fine Arts Education Facilities in Surabaya

A library and fine arts educational facility is an educational place to gain knowledge and introduce fine arts. Through observations, the researcher identified issues in Surabaya's libraries, such as the monotonous building structures and unattractive spatial atmosphere. Meanwhile, fine arts facilities lack resources for making art, so the integration of a library and fine arts education facility is necessary in one location. In this building, visitors can not only gain knowledge about art but also increase their creativity by learning while making works of art with artists. It serves as a solution to increase the reading interest index and introduce works of art more widely.The application of a contemporary architectural theme is based on the expressive characteristics of educational and artistic buildings, following current contemporary characteristics. Qualitative research with a descriptive approach depicts the experiences in the field, which were then analyzed using parameters of the function and feasibility of educational and artistic buildings.The design of the library and fine arts education facility applies the contemporary architecture theme to the macro concept of recreational education to provide a special attraction to visitors.The shape design uses an attractive micro concept by giving the building an identity through variations of curved lines, geometric shapes inspired by a book, and bright color combinations derived from mosaic paintings.

DSM design of cold-formed steel fixed-ended lipped channel columns undergoing distortional-global interaction

This work reports a numerical investigation dealing with the post-buckling behaviour, strength, and Direct Strength Method (DSM) design of cold-formed steel fixed-ended lipped channel columns experiencing coupling between distortional and global (flexural-torsional) buckling − distortional-global (D–G) interaction. Various cross-section dimensions and lengths are considered, to ensure that the columns selected undergo different levels and types (“true”, “secondary-bifurcation distortional” or “secondary-bifurcation global”) of D–G interaction. The results presented and discussed, determined by means of Abaqus shell finite element geometrically and materially non-linear analyses, consist of elastic and elastic-plastic post-buckling equilibrium paths, failure loads and collapse modes. The steel material behaviour is deemed elastic-perfectly plastic and several yield stresses are considered, thus making it possible to cover a wide column D–G slenderness range. Particular attention is devoted to identifying the most detrimental initial geometrical imperfection shapes, in the sense that they lead to the lowest column failure loads. The numerical failure load data gathered are subsequently used to assess the merits of the available DSM-based design approaches developed to handle cold-formed steel columns undergoing D–G interaction. Since these design approaches are shown to be either inefficient and/or improvable, the above failure load data are also used to propose modifications/improvements aimed at achieving an efficient failure load prediction in the specific context of fixed-ended lipped channel columns. The success of this endeavour provides encouragement to the authors in their search for a safe, accurate and reliable DSM-based design approach capable of handling cold-formed steel columns with arbitrary cross-section shapes and/or end support conditions that fail in D–G interactive modes.

Coupled Kite-to-Square Distortion Transition and Physical Properties in 2D Lead Halide Perovskite.

2D lead halide perovskites showcase diverse electrical and optoelectrical properties due to their adaptable structural distortion, which dictates the symmetry characteristics of the material. To accommodate the geometric shape of the cation, the inorganic layer of the 2D perovskite often undergoes specific distortions such as lead-halide bond length elongation/compression and lead atom displacement. The resultant distortion manifests as a quadrilateral shape formed by Pb atoms from four adjacent four octahedrons. The degree of distortion increases as the quadrilateral deviates further from a square shape and vice versa. This quadrilateral shape not only visually represents the magnitude of distortion but also confirms its direction. During the transition from kite to square distortion under external stimuli, the positions of the Pb atoms vividly illustrate the symmetry-breaking process, corresponding to a shift from high to low symmetry states. The electrical and optoelectronic properties, including ferroelectricity, pyroelectricity, piezoelectricity, nonlinear optical properties, and characteristics related to bulky photovoltaic effects, some of them exhibit direction dependence nature. This perspective employed a visible structural distortion approach to elucidate symmetry breaking and coupling distortion transitions with eight optoelectronic physical properties in 2D layered perovskite. We review recent research advancements and outline current challenges that help us to understand the structure-property relationship of 2D perovskite.

Finite element software for forming processes of glass containers

AbstractA two‐dimensional (2D) axisymmetric numerical model, based on the finite element method, for glass containers forming processes is presented. Glass forming processes involve coupled thermomechanical phenomena in which heat transfer and viscous flow are dependent, as glass viscosity is highly dependent on temperature. During the overall process glass changes from a molten state to a solid state. Therefore, adequate cooling conditions must be set appropriately. From the numerical point of view, the modeling must be robust so as to adjust to the different sequenced stages. Remeshing techniques requiring adequate data transfer, as well as, different thermal and mechanical contact conditions between glass and molds must be taken into account. Also, effective treatment of the incompressible conditions associated with glass flow must be dealt with. The aim is to set the better process parameters so that the final containers have the required geometrical shape and thickness distribution. A numerical model was conducted addressing all these issues and a thickness distribution comparison with real industrial products was performed.

A REVIEW OF THE RECENT RESEARCH ACTIVITIES IN THE FILD OF ELECTRICAL DISCHARGE MACHINING

Electrical discharge machining (EDM) is one of the earliest non-traditional machining processes being considered one of the most popular machining methods today. The EDM process basis on thermoelectric energy between the workpiece and an electrode, so that the discharge energy generated during the operation characterizes the productivity of the process. Due to the well-established machining options utilized in the industry of aerospace, automotive industry and surgical components for precision machining and making complex geometrical shapes in hard-to-cut materials, a significant amount of research interests has been created in this field. This paper provides a review of numerous academic research activities carried out in the previous years, as well as numerous developments in the field of EDM related to increased machining rates, improved performance, materials and dielectrics used, electrode design and manufacture.

Dynamics of geometric shape solutions for space-time fractional modified equal width equation with beta derivative

The modified equal width equation describes the propagation of shallow water waves in which nonlinear and dispersive effects are significant, including phenomena such as wave breaking, soliton interactions, ion-acoustic waves, energy transfer in plasma, and nonlinear stress waves. The aim of this article is to establish some novel and generic solutions to the space-time fractional modified equal width (MEW) equation using the two variable (θ′/θ, 1/θ)-expansion technique, a modification of the (θ′/θ)-expansion method. A wide range of geometric shapes and inclusive soliton solutions have been constructed, comprising rational, trigonometric, and hyperbolic solutions, along with their integration to the equation under consideration. The two- and three-dimensional graphs of the solitons, including periodic, V-shaped, bell-shaped, singular periodic, flat kink-shaped, plane-shaped, peakon, and parabolic, illustrate the physical aspects of the solitary wave solution and the effect of the fractional parameter. The results demonstrate the efficiency, appropriateness, and reliability of the adopted technique for investigating fractional-order nonlinear evolution equations in science, technology, and engineering.

An Empirical Study on the Upcycling of Glass Bottles into Hydrocyclone Separators

Cyclones are pivotal in mechanical process engineering and crucial in the complex field of separation technology. Their robustness and compact spatial requirements render them universally applicable and versatile across various industrial domains. Depending on the utilized fluid and field of application, both gas-based cyclones and hydrocyclones (HCs) are well established. Regarding HC design, enduring elongated flat cones have seen minimal alterations in shape and structure since their introduction over more than a hundred years ago. Experimental investigations regarding unconventional cone designs within scientific studies remain the exception. Therefore, this study focuses on alternative geometric configurations of the separation chambers and highlights their impact on separation and energy efficiency. To achieve this objective, different geometric shapes are investigated and retrofitted into HCs. The geometric foundation is derived from upcycled glass bottles. The repurposed bottles with a volume of 750 mL are used in conjunction with an inlet part, following the established Rietema design. Experimental tests are conducted with dilute phase separation, using 0.1–200 µm test particles in water. Comparisons between a bottle-based HC and a conventional Rietema design were conducted, establishing a benchmark against the standard. The findings revealed a noticeable correlation between separation efficiency and cone geometry. Conical designs demonstrated enhanced separation, particularly at lower volume flows. At the highest volume flow of 75 L min−1, the best performing bottle cyclones showed separation efficiencies of 78.5%, 78.4% and 77.9% and therefore are in a competitive range with 78.0% efficiency, achieved using the commercial Rietema design. Minimal disparities in cut sizes were observed in terms of separation grade efficiency among the models tested. Variations in separation efficiency and fractional efficiency curves indicated nuanced differences in classification efficiency.

Thermal performance and life cycle analysis of 3D printed concrete wall building

Automated construction process with extrusion-based 3D concrete printing (3DCP) is widely recognised due to its ability to construct complex freeform geometrical shapes. Furthermore, the automation process reduces labour and minimises material wastage, thus improving productivity. The structural performance of printed structures has been widely discussed; however, addressing the knowledge gap in energy performance and their environmental impact needs further investigation. Thus, this study investigated and compared the insulation characteristics, life cycle cost and environmental impact assessment of 3DCP structures with traditional reinforced concrete members. The evaluation of the insulation properties of 3D printable concrete allows the characterisation of operational costs and greenhouse gas emissions incurred from the additional heating and cooling systems. Furthermore, this study also suggested a method to enhance the thermal resistance of 3DCP with recycled fibre recovered from face mask waste. A comparison between face mask fibre-reinforced 3D-printed wall element and conventional reinforced concrete wall is also performed across the thermal, life cycle cost and environmental impact parameters. The results showed that the insulation properties of 3DCP walls were increased by 49.5% with the addition of face mask fibres compared to RC walls. This results in reduced energy consumption from additional heating and cooling systems along with a reduction in greenhouse gas emissions, thereby improving the energy performance of the building. Further, face mask fibre-reinforced printed walls showed a reduction in the life cycle cost, mainly in the operation stage, due to the low labour requirement and elimination of formwork. Moreover, a significant reduction in the depletion of resources and ozone depletion was observed for 3DCP face mask fibre-reinforced walls, along with the reduced impact on human health and ecosystem damage. Consequently, the incorporation of face mask fibres into the 3DCP process paves the way for its potential in constructing energy-efficient and environmentally sustainable buildings.

Two‐stage algorithm for traffic signal optimization and web‐service system development

AbstractEfficient control of traffic signals for vehicles and pedestrians at intersections is critical for relieving traffic congestion. Considering the unique characteristics of intersections, such as the number of roads, the presence or absence of crosswalks, road geometric shapes, and traffic demand patterns, an appropriate phase sequence and duration for traffic signals must be established at each intersection. This paper proposes a simulation‐based two‐stage algorithm comprising integer‐constrained Adam (ICA) and tabu search (TS) to optimize the phase sequence and duration for arbitrary intersections with arbitrary traffic‐demand patterns. The ICA promptly identifies a promising region in which a global optimal solution is likely to be obtained, whereas TS determines the best solution near the region. The performance of the proposed algorithm that optimizes phase durations with fixed phase sequence is evaluated against several baseline methods using 24 instances across six actual intersections. Experimental results show that the proposed algorithm reduces the average travel time by 20.2% compared with existing traffic signals within a computation time of 4 min, thus providing a near‐optimal solution eight times faster than commonly used population‐based metaheuristics. Furthermore, the algorithm demonstrates robust performance across heterogeneous vehicles and recommends the best phase sequence that effectively alleviates congestion in current traffic signal systems. The optimized phase sequence with best phase durations further reduces the average travel time by approximately 11.3% compared with the existing phase sequence with best phase durations at an actual intersection. To facilitate its widespread use, a free, open web‐service system named “Smart Intersection for Traffic Efficiency” is developed, which enables users to optimize traffic signal systems without requiring optimization background or simulation knowledge.

Semantic structures facilitate threat memory integration throughout the medial temporal lobe and medial prefrontal cortex

Emotional experiences can profoundly impact our conceptual model of the world, modifying how we represent and remember a host of information even indirectly associated with that experienced in the past. Yet, how a new emotional experience infiltrates and spreads across pre-existing semantic knowledge structures (e.g., categories) is unknown. We used a modified aversive sensory preconditioning paradigm in fMRI (n= 35) to investigate whether threat memories integrate with a pre-established category to alter the representation of the entire category. We observed selective but transient changes in the representation of conceptually related items in the amygdala, medial prefrontal cortex, and occipitotemporal cortex following threat conditioning to a simple cue (geometric shape) pre-associated with a different, but related, set of category exemplars. These representational changes persisted beyond 24h in the hippocampus and perirhinal cortex. Reactivation of the semantic category during threat conditioning, combined with activation of the hippocampus or medial prefrontal cortex, was predictive of subsequent amygdala reactivity toward novel category members at test. This provides evidence for online integration of emotional experiences into semantic categories, which then promotes threat generalization. Behaviorally, threat conditioning by proxy selectively and retroactively enhanced recognition memory and increased the perceived typicality of the semantic category indirectly associated with threat. These findings detail a complex route through which new emotional learning generalizes by modifying semantic structures built up over time and stored in memory as conceptual knowledge.