Characteristic Contours Research Articles

Modeling of fabric sewing break detection based on U-Net network

To solve the problem of false positives and false negatives in the manual detection of fabric sewing breaks, a method of fabric sewing break detection based on the U-Net network is proposed. By detecting the adjacent distance between the characteristic contours of adjacent sewing stitches, the distribution uniformity of sewing stitches in sewing patterns is calculated, and the abnormal detection and traceability of fabric sewing broken threads are realized. First, the U-Net network sewing feature extraction model was trained using sewing images and their corresponding stitching feature annotation maps. Then, the trained network model was used to process sewing image samples to obtain binary stitching feature maps. Second, the stitching feature maps were processed using a closing operation to eliminate residual image noise. On this basis, the template matching algorithm was used to extract the stitching feature contours. Finally, according to the distance between adjacent feature contours, the fabric sewing break detection and abnormality tracing model was constructed. The model is validated by examples, and the results show that the abnormal samples of stitching lines are detected, and the corresponding break positions are given. The overall detection accuracy of the model is 95.75%, indicating that the constructed fabric sewing break detection model is effective.

Wave velocity measurement in the through-thickness direction of the anisotropic material plate with ultrasonic polar scan

Ultrasonic polar scan (UPS) records the amplitude in transmission for a wide range of incidence angles, providing a UPS image with characteristic contours reflecting the acoustic parameters of the material. This study focused on a newly developed wave velocity measurement of the DD6 single-crystal material plate by analyzing the UPS image to realize the ultrasonic thickness measurement of the DD6 single-crystal material plate accordingly. Firstly, considering transducer contour size compensation, the UPS images are obtained by numerical simulation on the DD6 single-crystal material plates with different crystal orientations. Secondly, the fitting equations are obtained by analyzing the UPS images to calculate wave velocity in the thickness direction. Finally, a 5-joint UPS scanner is designed to validate the accuracy of wave velocity simulation results experimentally, and it indicates a good agreement with conventional ultrasonic velocity measurement. The measurement results demonstrated that the UPS method could evaluate the wave velocity in the through-thickness direction of the DD6 single-crystal material plate with high precision.

Area average heat transfer from a vertical flat plate impinged by circular inclined jet

ABSTRACT The inclined impinging jets owing to higher efficiency are widely used to disperse concentrated and transient heat loads. The temperature and heat transfer characteristics of jet cooling vertical hot plate at different inclinations are experimentally investigated. Experiments are performed to investigate the area average heat transfer over a flat surface of 600 × 300 mm2 placed at different location (z) of 3−20 d from the jet. The investigation is employed for Reynolds number based on hydraulic diameter of 11.5 mm ranging from 10,000 to 75,000. The orientation of the jet varies from 15° to 75°. The study aims to investigate the influence of jet orientation at different area locations on the surface from the point of impingement. The effect in stagnation region with different jet tilt is investigated. The area average temperature variation and characteristic temperature contours with increasing surface area and inclination is delineated. The characteristics of heat transfer on the surface’s periphery are studied. Heat transfer increases by 40% at lower tilt angle as the jet is displaced from 20 to 6 d, whereas the maximum average Nu occurs at higher inclination. The available Nusselt numbers in inclined jet are compared with present experimental results. A new empirical correlation is developed for a complete range of z/d, Re and large radial span.

ОСОБЕННОСТИ МОДЕЛИРОВАНИЯ РАСПРЕДЕЛЕНИЯ ВОДНЫХ РЕСУРСОВ НА СИСТЕМАХ ДВОЙНОГО РЕГУЛИРОВАНИЯ ВОДНОГО РЕЖИМА ПОЧВ

The aim of the research is to develop a modeling methodology for solving problems associated with the creation of simulation models and means of information and technological support for the tasks of allocating water resources on drainage systems for double regulation of the water regime of soils. The methodological and informational basis of the work was formed by the experience of creating and operating existing means of information technology support for the design and operation of double regulation drainage systems, the provisions of normative and technical documents on the automation of systems, as well as the design features of drainage and humidification and drainage systems. irrigation systems. As a result of studies of the problem of distribution of water resources on a specific system, the main stages were determined: the allocation of its blocks for which a system of water resources regulation is being developed, the allocation of subsystems in the structure, classification of tasks in subsystems, construction of an information model of the system, construction of a complex of models. To solve the problem associated with the development of simulation models and means of information technology support for the tasks of water resources distribution on dual control systems, it is proposed to use the method of contour modeling of water resources management regimes. The essence of the methodology consists in identifying characteristic contours in the structure of the water distribution network, for which you can use standard modeling algorithms and tools (quickly adjusted to the parameters of these contours) and sequentially calculating the parameters of the distribution of water resources for each of them. In this connection, the main control loops have been determined: the control loop «Water consumer № 1, 2 ... n», «Group of water consumers № 1, 2 ... n», «Section of the system № 1, 2 ... n» and «System». The proposed technique allows you to select typical control loops and then, in the selected standard loop, select characteristic control loops, along which simulation modeling of the processes of regulating the distribution of water resources over all control loops is carried out. The carried out simulation modeling of regulation processes throughout the «system» can be used by the maintenance service of the double regulation drainage system as variations in solutions when controlling the operation of regulatory structures, pumping stations and other structures of the system used to control water distribution.

Использование БПЛА Geoscan 201 для съемки линейного объекта трассы Хива–Ургенч

The aim of this work is to perform a linear aerial survey of the Khiva–Urgench highway using the Geoscan 210 UAV, the results of which will create orthophotomaps at a scale of 1:1 000, which are necessary for designing bicycle and sidewalk paths along this route. Surveyors of the Applied Geodesy Department of UZGASHKLITI performed a field planned-altitude reference at this object. 48 control points were determined. Characteristic solid contours along the route were chosen as reference points. The binding of control points was carried out from the starting points of the State Geodetic Networks, using satellite receivers (SN 5242498595, 5243499034, 4827155394) in the RTK mode in a radial way, by the calibration method on the ground. The coverage area was 17.4 sq. km. Aerial photography was carried out at a height of 211 m by a Geoscan 201 unmanned aerial vehicle at a scale of 1:500 with a DSC RXIR digital camera with a focal length of 35 mm. Forward overlap of aerial photographs was 70 %, and lateral—50 %. 4 aerial routes were made at this facility, the photography basis was 42 m. The number of aerial photographs at the facility was 3 868 pieces, and the coverage of aerial photography was 300 m. The images and their EXIF files were georeferenced by performing field processing using the Geoscan Planner program. Before the start of field work, the GNSS receiver (Trimble R6) was installed at a known point on the ground and started in static mode (10 Hz). The aircraft has a GNSS receiver (Topcon) operating in fast static mode (10 Hz). The GNSS data on the ground and on board the aircraft are balanced. Image center coordinates are calculated from the base station GNSS receiver data using MAGNET Tools software. Then the data is imported into Agisoft Metashape software for automatic processing. In this case, the coordinates of the image centers were recalculated from the WGS-84 system into the SK-42 (Pulkovo 1942) system adopted in our country. The process of optimization and alignment of aerial photographs was carried out. After that, in order to obtain a high image quality, the orthophoto map was built using a height map built on the basis of a dense point cloud. The result of the work performed are orthophoto maps for the Khiva–Urgench highway, which will be used to design the location of bicycle and sidewalk paths.

Finite element computation of magneto-hemodynamic flow and heat transfer in a bifurcated artery with saccular aneurysm using the Carreau-Yasuda biorheological model.

"Existing computational fluid dynamics studies of blood flows have demonstrated that the lower wall stress and higher oscillatory shear index might be the cause of acceleration in atherogenesis of vascular walls in hemodynamics. To prevent the chances of aneurysm wall rupture in the saccular aneurysm at distal aortic bifurcation, clinical biomagnetic studies have shown that extra-corporeal magnetic fields can be deployed to regulate the blood flow. Motivated by these developments, in the current study a finite element computational fluid dynamics simulation has been conducted of unsteady two-dimensional non-Newtonian magneto-hemodynamic heat transfer in electrically conducting blood flow in a bifurcated artery featuring a saccular aneurysm. The fluid flow is assumed to be pulsatile, non-Newtonian and incompressible. The Carreau-Yasuda model is adopted for blood to mimic non-Newtonian characteristics. The transformed equations with appropriate boundary conditions are solved numerically by employing the finite element method with the variational approach in the FreeFEM++ code. Hydrodynamic and thermal characteristics are elucidated in detail for the effects of key non-dimensional parameters i.e. Reynolds number (Re = 14, 21, 100, 200), Prandtl number (Pr = 14, 21) and magnetic body force parameter (Hartmann number) (M = 0.6, 1.2, 1.5) at the aneurysm and throughout the arterial domain. The influence of vessel geometry on blood flow characteristics i.e. velocity, pressure and temperature fields are also visualized through instantaneous contour patterns. It is found that an increase in the magnetic parameter reduces the pressure but increases the skin-friction coefficient in the domain. The temperature decreases at the parent artery (inlet) and both the distant and prior artery with the increment in the Prandtl number. A higher Reynolds number also causes a reduction in velocity as well as in pressure. The blood flow shows different characteristic contours with time variation at the aneurysm as well as in the arterial segment. The novelty of the current research is therefore to present a combined approach amalgamating the Carreau-Yasuda model, heat transfer and magnetohydrodynamics with complex geometric features in realistic arterial hemodynamics with extensive visualization and interpretation, in order to generalize and extend previous studies. In previous studies these features have been considered separately and not simultaneously as in the current study. The present simulations reveal some novel features of biomagnetic hemodynamics in bifurcated arterial transport featuring a saccular aneurysm which are envisaged to be of relevance in furnishing improved characterization of the rheological biomagnetic hemodynamics of realistic aneurysmic bifurcations in clinical assessment, diagnosis and magnetic-assisted treatment of cardiovascular disease."

A Study of the Applicability of Existing Compact Models to the Simulation of Memristive Structures Characteristics on Low-Dimensional Materials.

The use of low-dimensional materials is a promising approach to improve the key characteristics of memristors. The development process includes modeling, but the question of the most common compact model applicability to the modeling of device characteristics with the inclusion of low-dimensional materials remains open. In this paper, a comparative analysis of linear and nonlinear drift as well as threshold models was conducted. For this purpose, the assumption of the relationship between the results of the optimization of the volt–ampere characteristic loop and the descriptive ability of the model was used. A global random search algorithm was used to solve the optimization problem, and an error function with the inclusion of a regularizer was developed to estimate the loop features. Based on the characteristic features derived through meta-analysis, synthetic volt–ampere characteristic contours were built and the results of their approximation by different models were compared. For every model, the quality of the threshold voltage estimation was evaluated, the forms of the memristor potential functions and dynamic attractors associated with experimental contours on graphene oxide were calculated.

The prosody of focus: non-contrastive, contrastive and verum focus in Slovenian, English and Russian

The article presents an approach to information structure that marks focused or topicalized syntactic constituents with the features [foc] and [top], and assumes that the assignment of these information structure features is reflected in prosody. The experimental study measures the fundamental frequency of various Slovenian sentences to identify the characteristic contours of the non-contrastive, contrastive, and verum focus. The findings are compared to those in studies on English and Russian. The results show that the most relevant prosodic characteristics of such structures are the pitch range, the pitch changes on the focus exponent, and the duration of the focus exponent.

A free-boundary model of diffusive valley growth: theory and observation.

Valleys that form around a stream head often develop characteristic finger-like elevation contours. We study the processes involved in the formation of these valleys and introduce a theoretical model that indicates how shape may inform the underlying processes. We consider valley growth as the advance of a moving boundary travelling forward purely through linearly diffusive erosion, and we obtain a solution for the valley shape in three dimensions. Our solution compares well to the shape of slowly growing groundwater-fed valleys found in Bristol, Florida. Our results identify a new feature in the formation of groundwater-fed valleys: a spatially variable diffusivity that can be modelled by a fixed-height moving boundary.

5층 링 조명에 의한 BGA 볼의 검사 방법

Fast inspection of solder ball bumps in ball grid array (BGA) is an important issue in the flip chip bonding technology. Particularly, semiconductor industry has required faster and more accurate inspection of micron-size solder bumps in flip chip bonding, as the density of balls increase dramatically. In this paper, we describe an inspection approach of BGA balls by using 5-step ring illumination device and normalized cross-correlation (NCC) method. The images of BGA ball by the illumination device show unique and distinguishable characteristic contours by their 3-D shapes, which are called as iso-slope contours. Template images of reference ball samples can be produced artificially by the hybrid reflectance model and 3D data of balls. NCC values between test and template samples are very robust and reliable under well-structured condition. The 200 samples on real wafer are tested and show good practical feasibility of the proposed method.

How the molecular face and the interaction vary as H atom approach H2 molecule

First, we briefl y introduce the potential acting on one electron in a molecule ( PAEM ). Second, based on PAEM, the molecular intrinsic characteristic contours ( MICC) is defi ned uniquely and intrinsically, and then, the electron density distribution is mapped on the MICC which is called molecular face ( MF ), an identifi cation card, which is an intrinsic characteristic “ face ” or “ fi ngerprint ” for a molecule. Third, the polarization phenomena have been quantitatively demonstrated, i.e., the changing features of the spatial characteristic and the frontier electron density on the MF surface have been shown for reaction H 2 + H → H + H 2, denoted as H1 − H2 + H3 → H1 + H2 − H3, along the linear reaction path, which is compared with those quantities of the reaction H + H → H 2 process. Furthermore, the conversion between the van der Waals interaction and chemical bonding during the process of H1 − H2 + H3 → H1 + H2 − H3 reaction is shown by the PAEM -MO diagram, which provides insight into the characteristic of the interaction between two atoms: At the starting step of the reaction, the interaction between H1 and H2 atoms is chemically bonded, while the interaction between H2 and H3 is van der Waals interaction, and the contour of H2 atom in H 2 molecule does not overlap with that of the H3 atom, which means that the electron interfl ow between H1 and H2 atoms is free and the electron interfl ow between H2 and H3 atoms is blocked by a PAEM barrier or must tunnel the barrier. At the transition state, both the pair of H1 and H2 and the pair of H2 and H3 are chemically bonded.

Extraction of bulk wave characteristics from a pulsed ultrasonic polar scan

The pulsed ultrasonic polar scan (P-UPS) technique provides a map with characteristic contours reflecting the critical bulk wave angles, which directly relate to the in-plane elastic properties of the insonified material spot. Besides these contours, additional information is captured in a P-UPS experiment which has particular importance for the inspection of anisotropic materials. By extensive post-processing on a single P-UPS experiment, we successfully extracted the local directional (i) critical bulk wave angles, (ii) phase velocity profiles, (iii) slowness curves, (iv) walk-off angles and (v) energy velocity profiles, for the three different polarization states of bulk waves. The procedure is demonstrated and discussed for an isotropic aluminum sample as well as an autoclave manufactured orthotropic [0]8 carbon/epoxy laminate. In addition, a numerical and experimental investigation of the role of the immersion liquid as a lens for the P-UPS result is performed. This lensing effect permits to zoom in/out on the P-UPS fingerprint, hence broadening the class of materials which can be inspected by the P-UPS technique.

Theoretical and experimental determination of the number of water molecules breaking the structure of a glycine-based ionic liquid

The effects of water on the structures of the amino acid ionic liquid (IL) 1-ethyl-3-methylimidazolium glycine ([emim][Gly]) are explored by a classical simulation method. The density and surface tension of the [emim][Gly]–H2O mixture are experimentally studied by a standard addition method. Simulation and experiment show that the density of the [emim][Gly]–H2O mixture reaches the maximum at 2–4 mass% water. Different analysis tools, including radial distribution, an interstice model, and molecular intrinsic characteristic contours are used to describe the structural modifications of the [emim][Gly] and ionic aggregates as a function of the solution concentration. At xw < 0.33 (mole fraction), the isolated water and dimer are located at the interstices formed between the ions, do not modify the network of ILs, and slightly strengthen the interactions between the cation and anion. Consequently, a turnover in the evolution of the IL structures and properties ensues. At 0.33 < xw < 0.50, the formation of relatively large water clusters, such as trimers and tetramers, leads to interstice distention, breakage of the cation–anion network, and gradual loosening of the interactions. With a further increased water concentration, a bicontinuous phase is generated and ionic clusters disperse in a continuous water phase. The size and morphology of the water aggregates are evaluated and analyzed by several statistical functions.

Memory color of natural familiar objects: Effects of surface texture and 3-D shape

Natural objects typically possess characteristic contours, chromatic surface textures, and three-dimensional shapes. These diagnostic features aid object recognition, as does memory color, the color most associated in memory with a particular object. Here we aim to determine whether polychromatic surface texture, 3-D shape, and contour diagnosticity improve memory color for familiar objects, separately and in combination. We use solid three-dimensional familiar objects rendered with their natural texture, which participants adjust in real time to match their memory color for the object. We analyze mean, accuracy, and precision of the memory color settings relative to the natural color of the objects under the same conditions. We find that in all conditions, memory colors deviate slightly but significantly in the same direction from the natural color. Surface polychromaticity, shape diagnosticity, and three dimensionality each improve memory color accuracy, relative to uniformly colored, generic, or two-dimensional shapes, respectively. Shape diagnosticity improves the precision of memory color also, and there is a trend for polychromaticity to do so as well. Differently from other studies, we find that the object contour alone also improves memory color. Thus, enhancing the naturalness of the stimulus, in terms of either surface or shape properties, enhances the accuracy and precision of memory color. The results support the hypothesis that memory color representations are polychromatic and are synergistically linked with diagnostic shape representations.

Fast and Automatic Identification of Contours for Girth Measurement on 3D Human Models with Variant Postures

AbstractWe develop a novel method for fast and automatic identification of characteristic contours for measuring girths on digital 3D human models with various stable postures. For fast identification, the characteristic contours with salient topology and geometric features are selected among the multi-source geodesic iso-contours, which are constructed under a new Morse function as using multi-source points to compute geodesic distance instead of using solely one source point. The resulting iso-contours are stable in a wide range of postures due to the bending invariance of geodesic distance. Based on the characteristic contours, we develop an efficient algorithm to extract the contours for girth measurement. We present a number of experiments on 3D human body samples with variant postures to demonstrate the validity of our approach.

Simple modified freezing technique for identification of human scalp and pubic hairs

BackgroundExamination of the macroscopic and microscopic appearance of human hairs is of great importance in forensic investigations. ObjectiveThe aim of this study is to establish a simple and a low-cost freezing technique for hair cross-sectioning especially suited for use in developing countries. The devised technique is further applied for the differential identification of microscopic cross-sections of human hairs obtained from two different body regions (scalp or pubic). Material and methodsSamples of human hair from both head and pubic regions obtained from Egyptian volunteers of both sexes. A simple modified freezing technique was devised for making cross-sections of the hairs. The modified steps of this technique are suggested by the author. ResultsThere were marked differences between the characteristic regular contours of hair sections obtained from head hairs as compared with the irregular contours of those from the pubic region. ConclusionsThe devised modified freezing technique used in the present study can be considered as a reliable method for making cross-sections of hairs. In addition it is rapid, simple and low cost compared to other methods; thus making it more suited for use in developing countries.

Mars Entry Bank Profile Design for Terminal State Optimization

One challenge examined in NASA’s DRM 5.0 study is that of entry, descent, and landing (EDL) on Mars for high-ballistic-coefficient, human-class payloads. To define best-case entry scenarios for the evaluation of potential EDL system designs, a study is conducted to optimize the entry-to-terminal-state portion of EDL for a variety of entry velocities, vehicle ballistic coefficients ( �), and lift-to-drag ratios ( L/D ). The terminal state is envisioned as one appropriate for the initiation of terminal descent via parachute or other means. A particle swarm optimizer varies entry flight path angle and ten bank profile points to find maximum-final-altitude trajectories. A baseline set of optimizations is performed, as are fulllift-up and relaxed-deceleration-constraint sets fo r comparison. In total, an estimated 9 million trajectories are analyzed to yield 1800 opt imal trajectories. Parametric plots of maximum achievable altitude are shown, as are examples of optimized trajectories. Characteristic vehicle contours are overlaid on the parametric plots, and conclusions are drawn on the feasibility of vehicles in the L/D vs. � design space. It is shown that entry bank angle control is highly deserving of consideration early in design, particularly for vehicles with mid- or high-L/D values, high entry velocities, and deceleration-li mited trajectories. Key conclusions are also drawn regarding trends in optimal bank profiles and in the constraints which impose particularly severe limits on the design of these trajectories.

Edge Extraction by an Exponential Function Considering X-ray Transmission Characteristics

3-D radiographic methodology has been into the spotlight for quality inspection of mass product or in-service inspection of aging product. To locate a target object in 3-D space, its characteristic contours such as edge length, edge angle, and vertices are very important. In spite of a simple geometry product, it is very difficult to get clear shape contours from a single radiographic image. The image contains scattering noise at the edges and ambiguity coming from X-Ray absorption within the body. This article suggests a concise method to extract whole edges from a single X-ray image. At the edge point of the object, the intensity of the X-ray decays exponentially as the X-ray penetrates the object. Considering this X-Ray decaying property, edges are extracted by using the least square fitting with the control of Coefficient of Determination.

Abstraction of man-made shapes

Man-made objects are ubiquitous in the real world and in virtual environments. While such objects can be very detailed, capturing every small feature, they are often identified and characterized by a small set of defining curves. Compact, abstracted shape descriptions based on such curves are often visually more appealing than the original models, which can appear to be visually cluttered. We introduce a novel algorithm for abstracting three-dimensional geometric models using characteristic curves or contours as building blocks for the abstraction. Our method robustly handles models with poor connectivity, including the extreme cases of polygon soups, common in models of man-made objects taken from online repositories. In our algorithm, we use a two-step procedure that first approximates the input model using a manifold, closed envelope surface and then extracts from it a hierarchical abstraction curve network along with suitable normal information. The constructed curve networks form a compact, yet powerful, representation for the input shapes, retaining their key shape characteristics while discarding minor details and irregularities.

MOLECULAR FACE — A NOVEL MOLECULAR MODEL SHOWING BOTH MOLECULAR SPATIAL CONTOUR AND FRONTIER ELECTRON DENSITY

The spatial knowledge is the first one of all information about an object. Molecular shape and size, molecular van der Waals surface and/or solvent-accessible surface etc. have been widely studied and applied. This paper is to show that a molecular face (MF) for a molecule may be defined uniquely and intrinsically via the molecular intrinsic characteristic contours (MICC) with coding the molecular electron density (ED) as the fourth dimension. The significant feature of an MF provides both molecular spatial appearance and its frontier electron density, being an intuitive picture as a molecular fingerprint or face. With simple examples, the physical significance of an MF is then demonstrated.