Grid Lines Research Articles

Catalyst‐enhanced plasma oxidation of n‐butane over α‐MnO2 in a temperature‐controlled twin surface dielectric barrier discharge reactor

AbstractA twin surface dielectric barrier discharge is used for the catalyst‐enhanced plasma oxidation of 300 ppm n‐butane in synthetic air. Plasma‐only operation results in the conversion of n‐butane into CO and CO2. Conversion is improved by increasing the temperature of the feed gas, but selectivity shifts to undesired CO. α‐MnO2 is used as a catalyst deposited on the electrodes by spray coating with a distance of 1.5 mm between the uncoated grid lines and the square catalyst patches to prevent the inhibition of plasma ignition. The catalyst strongly influences selectivity, reaching 40% conversion and 73% selectivity to CO2 at a specific energy density of 390 J·L−1 and 140°C, which is far below the onset temperature of thermocatalytic n‐butane conversion.

A Review on Shoulder Surfing Attack in Authentication Technique using Cued Click Point (CCP)

Security important now a days. Users of primary preference to security. Authentication process provide security to the user. Authentication process of identifying the person’s identity or conforming the identity of person. There are various authentication method, but most commonly used method is textual password. Combination of alphabet and number create a secure password. But some drawbacks i.e. it easily guess by also called attacker. If it make complex then it hard to memorize. Also various attacks brute force attack, dictionary attack, social engineering attack, evesdropping, etc. of textual password graphical password system introduced. Graphical system is easy to memorize but it undergo shoulder surfing attack which big problem. any entity or person can observe users password directly or by using any device. So as an alternative Graphical Passwords are introduced to resist the Shoulder surfing attack. the above mentioned attacks the new scheme highlights cued click point (CCP), Using graphical password as input and grid lines for image point verification. This paper survey shoulder surfing attacks in graphical password approach.

Circle formation by asynchronous opaque robots on infinite grid

This paper presents a distributed algorithm for circle formation problem under the infinite grid environment by asynchronous mobile opaque robots. Initially all the robots are acquiring distinct positions and they have to form a circle over the grid. Movements of the robots are restricted only along the grid lines. They do not share any global co-ordinate system. Robots are controlled by an asynchronous adversarial scheduler that operates in Look-Compute-Move cycles. The robots are indistinguishable by their nature, do not have any memory of their past configurations and previous actions. We consider the problem under luminous model, where robots communicate via lights, other than that they do not have any external communication system. Our protocol solves the circle formation problem using seven colors. A subroutine of our algorithm also solves the line formation problem using three colors.

New approximations for one-dimensional 3-point and two-dimensional 5-point compact integrated RBF stencils

This paper presents some new compact approximation stencils based on integrated radial basis functions (IRBFs) for numerically solving second-order elliptic differential problems on Cartesian grids. Higher-order IRBF schemes are employed to approximate the field/dependent variable. The IRBF approximations in each direction are based on 3 points and constructed independently, where derivatives of the second, third, fourth, fifth and sixth orders along the grid line are enforced at the two end-points. The imposed nodal derivative values are simply acquired through a Picard-type iteration scheme. The stencil is made up of 3 points and 5 points for 1D and 2D discretisations, respectively. Numerical results show that the proposed stencils yield a high rate of convergence with respect to grid refinement, e.g. up to the 13th order for 1D problems and to the 9th order for 2D problems.

Exponential fractional cat swarm optimization for video steganography

In this paper, an effective method named Exponential Fractional-Cat Swarm Optimization (Exponential Fractional-CSO) along with multi-objective cost function is proposed. The proposed method is designed by integrating the CSO with the fractional concept based on the Exponential parameters. Initially, an input video is selected from the database from which frames are generated. Key frames are chosen among the frames using the contourlet transform and Structural Similarity Index Measure (SSIM). Regions are formed on the selected key frames through the help of grid lines. Once the regions are formed, optimal regions are ascertained with the help of the proposed optimization algorithm along with multi-objective cost functions to hide the secret data. During the embedding process, the secret data is hidden in the optimal region using the lifting wavelet transform (LWT). The embedded video is then transmitted through the network to reach its intended receiver. The experimental results reveal that the proposed Exponential Fractional-CSO obtained a maximal correlation of 0.9931 by considering the frames, maximal Peak Signal-to-Noise Ratio (PSNR) of 89.70 dB and MSE of 0.00006 respectively. Hence, the proposed method shows greater effectiveness of hiding the secret data in the video sequence along with data security.

Study on performance degradation and damage modes of thin-film photovoltaic cell subjected to particle impact

It has been a key issue for photovoltaic (PV) cells to survive under mechanical impacts by tiny dust. In this paper, the performance degradation and the damage behavior of PV cells subjected to massive dust impact are investigated using laser-shock driven particle impact experiments and mechanical modeling. The results show that the light-electricity conversion efficiency of the PV cells decreases with increasing the impact velocity and the particles’ number density. It drops from 26.7 to 3.9% with increasing the impact velocity from 40 to 185 m/s and the particles’ number densities from 35 to 150/mm2, showing a reduction up to 85.7% when being compared with the intact ones with the light-electricity conversion efficiency of 27.2%. A damage-induced conversion efficiency degradation (DCED) model is developed and validated by experiments, providing an effective method in predicting the performance degradation of PV cells under various dust impact conditions. Moreover, three damage modes, including damaged conducting grid lines, fractured PV cell surfaces, and the bending effects after impact are observed, and the corresponding strength of each mode is quantified by different mechanical theories.

An automatic calibration algorithm for laser vision sensor in robotic autonomous welding system

Visual sensor plays an important part in intelligentized welding systems, and the calibration of the vision sensor is the indispensable part of visual systems. Aiming at the problem of the tedious calibration process, this paper describes an automatic calibration algorithm. First, the robot motion equation and the motion range constraint equation are proposed to ensure that the collected images of calibration grid and laser line meet the calibration requirements. Based on these two equations, the automatic collection procedure can be realized. Second, the simplified visual servoing method and the Extended Kalman filter were used to adjust the images and rectify system parameters, respectively, which will improve the stability of the calibration motion. Third, to reduce the impact of the complex welding environments, a robustness feature extraction algorithm based on local threshold is studied. And then, the laser plane and hand-eye matrix are fitted with optimization algorithms to ensure calibration accuracy. Finally, the simulation experiments prove the feasibility and stability of the proposed algorithm. And the actual calibration tests suggest that the algorithm can significantly improve calibration efficiency. Moreover, the experimental results of welding guidance and seam tracking confirm that the calibration precision has met the welding requirement.

Breaking Symmetries on Tessellation Graphs via Asynchronous Robots: The Line Formation Problem as a Case Study

Concerning the coordination of autonomous mobile robots, the main focus has been on the important class of Pattern Formation problems, where the robots are required to arrange themselves to form a given geometric shape. This class of problems has been extensively studied in the continuous environment (e.g., the Euclidean plane), whereas few results exist when robots move in a discretization of the plane, like infinite grids. In this environment, to form any pattern, the problem of breaking symmetries emerges. Breaking the symmetry by moving some leader robot is not a straightforward task due to the movement restrictions as all the adjacent nodes of the leader may be occupied. It may even happen that before obtaining the requested asymmetric configuration, most of the robots must be moved. Due to the asynchrony of robots, this fact greatly increases the difficulty of the problem. We assume very weak robots moving on any regular tessellation graph as a discretization of the Euclidean plane, and we devise an algorithm Abreak able to solve the Symmetry Breaking problem on both the square and triangular grids. It is important to note that Abreak is proposed so that it can be used as a module for solving more general problems. As a case study, we use Abreak to deal with the Line Formation problem, where n≥3 robots must arrange themselves to occupy n contiguous vertices along a grid line. In this respect, we first provide an algorithm ALF- able to partially solve this problem (it works with configurations in which it is not necessary to break symmetries), and then we show how Abreak and ALF- can be combined to form ALF. We provide a complete characterization of the solvability of the Line Formation problem on the considered topologies by showing that ALF solves the problem in each configuration where this is possible.

Design of intelligent distribution network based on Geographic Information Technology

According to the business requirements of distribution network planning, this paper deeply studies the existing simplified display algorithm of distribution network in GIS, constructs the distribution network model based on geographic information technology, develops the functions of supporting storage, display and display, and the function module of professional map editing for distribution network planning. The concept of spatiotemporal data and its application in GIS are innovatively put forward. The display research based on the status quo and the analysis and management technology of distribution network structure under planning state are carried out. The spatiotemporal representation, spatiotemporal evolution, and comparison of power grid are realized. The geographic image elements are matched and associated with equipment parameters to realize the integrated modeling of map and power grid, realize the penetration function from the map to equipment parameters and power grid indicators, and support the diagnosis and analysis of power grid-related indicators. Finally, a three-dimensional power map with time dimension, space dimension, and attribute dimension is constructed to provide geographic environment and equipment parameter data for power grid planning, site selection, and line selection.

Hierarchical Coordinated Control Method for Multiload DC Microgrid Units

Electricity has become not merely a source of power but also a vital component of our lives in a rapidly changing world. However, according to a World Bank report, 17% of the globe’s population live without power. The key cause for such a huge population not being electrified is the proximity of the central electrical grid system or the high expenditure of installing the grid lines to such remote areas. The notion of a microgrid was first proposed more than a decade ago, but the numerous obstacles it entails have hampered its broad adoption and made it a research focus in recent years. A hierarchical control structure of the microgrid is designed, which is divided into layers according to the control objectives and control time scales of the microgrid, and the hierarchical control structure is realized by using multiagent technology. In the framework of hierarchical control, aiming at the demand of energy coordination and optimization of the microgrid, the operation strategy of the microgrid is proposed in grid‐connected and/or off‐grid mode. In the grid‐connected mode, the large power grid is used for power supply and in the off‐grid mode, the load bidding mechanism is introduced to ensure the power supply of important loads. Experiment results reveal the power quality and stability of the system.

Возможности сравнения разновременных снимков различного разрешения при исследованиях динамики северных дельт

With the warming of the climate and the resumption of the Northern Sea Route, studies of the dynamics of the northern deltas, that close the exit to the ocean, have intensified. The best way to detect changes is to compare images, obtained at the end of the last century from the Landsat/ETM satellite (resolution R = 30 m) and modern Sentinel-2/MSI images (R = 10 m). To identify the effect of differences in the resolution of the compared images on the accuracy of determining changes in the coastline, a graphical simulation of reproducing changes (areas of coastal erosion or sediment accumulation) at the pixel level was performed. Reproduction of changes had been simulated for coastlines, that coincide in the direction of the pixel grid lines and deviate from them at angles of 15°, 30°, 45°, when the coastline is shifted from 10 to 40 m. It has been revealed that it is possible to determine the displacement of the coastline starting from the value of 20 m from multitemporal images with a resolution of 30 and 10 m. For coastlines directed along the pixel grid lines, it is possible to downplay (or exaggerate) the washout (or accumulation) band by 1/2 RL + 1/2 LS = 20 m. Coastlines that are tilted to the pixel grid may show false changes, especially if the shoreline position is unchanged or the offset is small (10 m). The kind of the distortion strongly depends on the position of the real coastline within the large Landsat pixels. The greatest distortions are characteristic of coastlines that occupy a peripheral position in the cells of the pixel grid. The simulation results should be used when preparing palettes to determine changes from combined multi-temporal images.

Accuracy and reliability of a smartphone application for measuring the knee joint angle.

[Purpose] Recently, a photo-based smartphone application for angle measurement—“Grid line imaging application Professional”—was developed to evaluate joint disease treatments. The aim of this study was to determine the accuracy and reliability of the application. [Participants and Methods] We measured the knee joint of a mannequin using an application and a universal goniometer. Twelve examiners measured eight knee joints of mannequins at different arbitrary angles using the application and a universal goniometer. Correlations between the application and universal goniometer measurements were examined using scatter plots and correlation coefficients. Systematic errors of the application were visually confirmed using the Bland-Altman method. Intra-class correlation coefficients were used to evaluate the inter-examiner reliability of the application. [Results] The application and universal goniometer measurements showed a good correlation (r=0.99) and no systematic error. The intra-class correlation coefficient for inter-examiner reliability was 0.999. Furthermore, to evaluate intra-examiner reliability, six examiners measured six different knee joints twice using the application on a 2-day interval. The intra-class correlation coefficient for intra-examiner reliability was 0.982. [Conclusion] The accuracy of the application was equivalent to that of a universal goniometer, and both the inter- and intra-examiner reliabilities of the application were almost perfect.

Minimum Number of Bends of Paths of Trees in a Grid Embedding

We are interested in embedding trees T with ∆(T) ≤ 4 in a rectangular grid, such that the vertices of T correspond to grid points, while edges of T correspond to non-intersecting straight segments of the grid lines. Such embeddings are called straight models. While each edge is represented by a straight segment, a path of T is represented in the model by the union of the segments corresponding to its edges, which may consist of a path in the model having several bends. The aim is to determine a straight model of a given tree T minimizing the maximum number of bends over all paths of T. We provide a quadratic-time algorithm for this problem. We also show how to construct straight models that have k as its minimum number of bends and with the least number of vertices possible. As an application of our algorithm, we provide an upper bound on the number of bends of EPG models of VPT ∩ EPT graphs.

АНАЛИЗ ВЛИЯНИЯ КОНСЕРВАТИВНОГО СГЛАЖИВАНИЯ КОНЕЧНО-ЭЛЕМЕНТНОГО РЕШЕНИЯ НА ПОДАВЛЕНИЕ МОД НУЛЕВОЙ ЭНЕРГИИ

The problem of high-speed penetration of a non-deformable cylinder into a steel plate is considered. The defining system of equations is formulated in Lagrange variables in a three-dimensional formulation. The equation of motion is derived from virtual work capacities balance. Kinematic relations are recorded in the metric of the current state. The relations of the flow theory with kinematic and isotropic hardening are used as equations of state. The contact interaction of the cylinder and the plate is modeled by non-penetration conditions. The numerical solution of the problem under given boundary and initial conditions is based on the moment scheme of the finite element method and “cross” type explicit time integration scheme. To discretize the defining system of equations with respect to spatial variables, 8-node isoparametric finite elements with multilinear form functions are used. To suppress the high-frequency oscillations of the numerical solution, the procedure of nodal displacement velocities conservative smoothing is used. The smoothing algorithm is based on the momentum conservation law, focused on finite element grids consisting of blocks that are mutually unambiguously mapped to a unit cube. To analyze the nodal displacement velocities monotonicity, the numerical solution splitting in the directions of the finite element grid lines is used. As the results of computer modeling have shown, the finite elements of the plate are exposed large deformations and rotation angles as a rigid whole during local intense dynamic loading. The conservative smoothing procedure influence on the numerical solution stability is analyzed. It is shown that in the problem under consideration, without applying the conservative smoothing procedure, zero-energy modes develop in the contact zone in the finite-element grid of the plate (an hourglass-type instability) and the collision process cannot be modeled before the cylinder rebounds.

A Resilience Assessment Framework for Distribution Systems Under Typhoon Disasters

With the increase of extreme natural disasters and the frequent occurrence of man-made attacks, resilience studies of power grids have attracted much attention, among which resilience assessment reflects the resistance and resilience of power systems to cope with extreme disasters. To improve the resilience of distribution grids under extreme weather conditions, this paper proposes a resilience assessment framework for distribution grids under typhoon disasters. First, a probabilistic generation model of typhoon is established. Second, a spatiotemporal vulnerability model of the distribution grid lines to quantify the spatiotemporal impacts of typhoon. Third, a breadth-first search algorithm is used to island the distribution grid, and the amount of load shedding of the islanded microgrid is calculated. Meanwhile, the resilience of the distribution grid was quantitatively assessed according to the proposed new resilience index. Finally, the feasibility of the proposed resilience assessment method is verified in the IEEE 33-bus test system, and the results show that the proposed method can accurately account for the impact of typhoon on the distribution grid and provides a quantitative reference basis for later power system planning and scheduling.

Quantitative Prediction Method for Distribution Power Grid Risk

The electric power distribution grid is directly oriented to the majority of the ordinary users. Traditional operation and maintenance are performed mainly based on experience, which disable to rationally evaluate the status of the line and predict faults. Based on big data, the risk of the line is evaluated through principal component analysis in this paper, so that a machine learning algorithm is carried out to calculate the risk value of the distribution grid line unit. Finally, GA-BP neural network is used to build a line risk value prediction model for improvement.

Sand Dredging in Anyang River and its Implication on Morphological Structure in Edebom II, Nsit Ibom, Akwa Ibom State, Nigeria

This study focused on sand dredging in Anyang Nsit River and its implication on morphological structure in Edebom II, Nsit Ibom, Akwa Ibom State, Nigeria, a third order tributary of Kwa Iboe river basin, which entails the morphometric parameters, dredging induced hazards, measurement and calculation of hydraulic parameters at two high dredging sites, are related to the dynamic nature of the river channel. Digital Elevation Model (DEM) of the study area with resolution 30x30m was obtained from United States Geological Survey (USGS) and the river channel was delineated. With the aid of Arc GIS 10.3 software package and Erdas Imagine 9.2 software reprojection and the map was produced in the layout view on a scale of 1:187500. The linear, areal and relief aspects of the sub-catchment were derived using strings and constructed grid lines placed on the map, while morphometric parameters of the river channel were calculated using relevant statistical package. The hydraulic parameters (bank full width, mean depth, velocity) of the two dredging sites were measured in a period of four months (MarchJune). The results showed that hydraulic parameters of these dredging points have changed significantly within this period. The calculated channel discharge had increased by 10m3/s and 7.42m3/s respectively at the two dredging sites. A total of 26,804 tonnes of dry weight sand is dredged both manually and mechanically (hydraulically) between March-June, 2021 which is consistent with the assertion that sand dredging is responsible for the change in the channel morphology especially in depth and deformation of channel configuration parameters. It was recommended that sand dredging in Akwa Ibom should be monitored by the Ministry of Environment as a statutory responsibility to maintain morphometric parameters in Akwa Ibom State, Nigeria.

Detection of Common Foreign Objects on Power Grid Lines Based on Faster R-CNN Algorithm and Data Augmentation Method

Foreign objects hanging on the electrical equipment are big threats to the safety of the power grid. In this paper, a high-precision object detection model designed for common foreign objects in power grid based on Faster R-CNN algorithm is proposed. The data augmentation methods such as rotation, adjusting brightness and colour saturation, adding Gaussian noise are carried out to expand the data in the training set. The accuracy rate and the recall rate of the model reach 93.09% and 94.33% respectively. The object detection model trained by the training set with data augmentation has achieved better detection results.

High-resolution additive direct writing of metal micro/nanostructures by electrohydrodynamic jet printing

Patterned conductive structures have attracted significant attention as important components of printed and flexible micro/nanodevices. However, the fabrication of conductive micro/nanostructures with controlled and well-organized morphologies is a key challenge in the development and application of micro/nanoelectronic devices based on low-dimensional materials. To meet the requirements of depositing conductive structures on specific substrates, electrohydrodynamic jet (E-jet) printing, developed as a simple and effective method for fabricating micro/nanopatterns of polymers, was combined with a conventional wet metal etching process for patterning conductive metals on polymer substrates. Under optimized experimental conditions, we achieved fine straight-line patterns with a line spacing of 1 μm at a nanoscale printing resolution (average line width: 68 nm) and grid patterns with variable spacings and grid line widths, down to size of 871 nm. Furthermore, fully printed graphene photodetectors were obtained through in situ direct writing, and their photoelectric response to a change in photocurrent of 0.22 μA was demonstrated. The results suggest that combining E-jet printing with chemical etching is a promising mask-free approach for producing conductive metal patterns for micro/nanoelectronic devices.

StoBEST: an efficient methodology for increased spatial resolution in two-component molecular tagging velocimetry

A new methodology to analyze two-component molecular tagging velocimetry image pairs is presented. Velocity measurements with high spatial resolution are achieved by determining grid displacements at the intersections as well as along the grid lines using a multivariate adaptive regression splines parameterization along the segments connecting adjacent grid intersections. The methodology can detect the orientation of the grid, contains redundant steps for increased reliability, and handles cases where parts of the grid are missing, indicating potential for automation. Initial demonstration of the algorithm’s performance was illustrated using synthetic data sets derived from Computational Fluid Dynamics simulations and compared to Hough-transform and cross-correlation methodologies. Besides providing comparable results in terms of precision and accuracy to previously reported methodologies, the analysis of images by the proposed methodology results in significantly increased spatial resolution of the flow displacement determinations along the grid lines with comparable precision and accuracy. This methodology’s ability to handle different grid orientations without modifications was assessed using synthetic datasets with grids formed by sets of parallel lines at 90, 45, and 30 degrees from the vertical axis. Comparable results in terms of precision and accuracy were obtained across grid orientations, with all uncertainties below 0.1 pixel for images with signal-to-noise levels exceeding 5, and within 0.5 pixel for the noisiest image sets.