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Binary rat swarm optimizer algorithm for computing independent domination metric dimension problem
Get PDFIn this article, we look at the NP-hard problem of determining the minimum independent domination metric dimension of graphs. A vertex set B of a connected graph G(V,E) resolves G if every vertex of G is uniquely recognized by its vector of distances to the vertices in B. If there are no neighboring vertices in a resolving set B of G, then B is independent. Every vertex of G that does not belong to B must be a neighbor of at least one vertex in B for a resolving set to be dominant. The metric dimension of G, independent metric dimension of G, and independent dominant metric dimension of G are, respectively, the cardinality of the smallest resolving set of G, the minimal independent resolving set, and the minimal independent domination resolving set. We propose the first attempt to use a binary version of the Rat Swarm Optimizer Algorithm (BRSOA) to heuristically calculate the smallest independent dominant resolving set of graphs. The search agent of BRSOA are binary-encoded and used to identify which one of the vertices of the graph belongs to the independent domination resolving set. The feasibility is enforced by repairing search agent such that an additional vertex created from vertices of G is added to B, and this repairing process is repeated until B becomes the independent domination resolving set. Using theoretically computed graph findings and comparisons to competing methods, the proposed BRSOA is put to the test. BRSOA surpasses the binary Grey Wolf Optimizer (BGWO), the binary Particle Swarm Optimizer (BPSO), the binary Whale Optimizer (BWOA), the binary Gravitational Search Algorithm (BGSA), and the binary Moth-Flame Optimization (BMFO), according to computational results and their analysis
Crack recognition and defect detection of assembly building constructions for intelligent construction
Get PDFVision-assisted surface defect detection technology is shallowly applied in crack identification of assembly building components, for this reason, the study proposes a crack identification and defect detection method for assembly building components oriented to intelligent construction. An image preprocessing algorithm is designed by improving bilateral filtering, on the basis of which an image classification model is constructed using the GhostNet algorithm, and the cracks are localized and measured using the 2D pixel positioning technique. Algorithm validation showed that the processed image denoising is better, and the peak signal-to-noise ratio of the image of the proposed algorithm is improved by 15.701 % and 2.395 %, respectively, compared to other algorithms. The F1 value of the proposed model after 50 training rounds increased by 20.970 % on average compared to other models, and the detection accuracy was as high as 0.990. The actual measurements of cracks in concrete wall panels revealed that the research-proposed method has better results compared to the traditional manual measurements, and is not subject to the limitations and interferences of factors such as manual experience, and it is more effective in the recognition of crack images. Overall, the detection method proposed by the study has high accuracy and small error, can meet the needs and standards of crack detection in assembly building components, and can intelligently locate the maximum length and width coordinates of the cracks, which is of high value in the application of crack detection in assembly building components
A ball screw all-round error compensation technology based on novel hybrid deep learning for CNC machine tool
Get PDFConsidering the detrimental impact of thermal phenomena on the geometric precision of machine tools, a machine tool ball screw’s omni-directional error model is created using the LSTM neural network algorithm. Subsequently, the machine tool ball screw's omni-directional error compensation module is devised by combining the core functions of the Huazhong numerical control system with the visual programming environment of QT and the numerical computation capability of Matlab. To enhance the practicality and accuracy of the compensation model, this study has employed the Whale Optimization Algorithm (WOA) to optimize the parameters of the LSTM model. This has resulted in an improvement in the model's generalization ability and prediction performance, making it more effective. During the experimental validation phase, the Z-axis error of the machine tool was practically operated and analyzed using the compensation method. Results manifestly show that, after employing the compensation method, the peak amplitude of the Z-axis error fluctuations have been notably curtailed to ±0.006 mm – a considerable reduction compared to the initial error bandwidth of ±0.0145 mm. These empirical findings substantiate the efficacy of the proposed compensation strategy in substantially boosting the machining precision of products, thus furnishing a substantial and instructive benchmark for future inquiries into CNC machine tool error compensation technologies
Development of an empirical model for the prediction of the sound absorption coefficient for thin and low-density fibrous materials
Get PDFCurrently, FEA software such as ABAQUS uses empirical models to predict the sound absorption coefficient of poroelastic materials. However, based on a recent review of the literature it was found that the current sound absorption empirical models are inadequate for accurate prediction of thin (t < 20 mm), low-density materials (ρB < 50 kg/m3). Therefore, the predictions of the sound pressure levels in vehicle cabins, using such software, will be inaccurate since the trim materials are thin and have a low density. Thus, this research aimed to develop an empirical model that can accurately predict the sound absorption coefficient of these materials. Hence, polypropylene fibres consisting of four different diameters were manufactured and converted into nonwovens. Thereafter, airflow resistivity and impedance tube experimental testing were performed on the specimens. Subsequently, statistical analysis of the data was performed using SAS software. SAS was used to identify which independent variables should be included in the models to be developed. The empirical models were developed using the regression analysis toolbox in Microsoft Excel. Once the models were developed, various checks were performed to validate the assumptions of linear regression. The software NumXL was used to perform Cook’s distance tests. Thereafter, the models were validated against the validation dataset, where it was found that the developed exponential model performed best. Finally, the exponential model was compared to existing models using two data sets i.e. an internal dataset, and an external dataset derived from the literature. The developed model outperformed all the historic models on both datasets
Active suspension LQR control based on modified differential evolutionary algorithm optimization
Get PDFThe selection of weight matrices Q and R in the LQR control strategy for active suspension is susceptible to subjective interference. To address this issue, a modified differential evolutionary algorithm is proposed to optimize the active suspension LQR controller, ensuring that the weighting coefficients are set to their optimal values. The differential evolutionary algorithm exhibits drawbacks in terms of its slow convergence rate and the significant impact of algorithm parameter settings on the obtained results. An modified differential evolutionary algorithm that is adaptive to the two candidate mutation strategies and adaptively adjusts the scaling factor and crossover rate is proposed so as to better improve the ability of jumping out of the local optimum and global search. The algorithm's functionality is verified by constructing a 1/4 suspension model in the Simulink software platform and implementing a modified differential evolution algorithm program written in C++ language using MATLAB. The program iterates through Simulink inputs to obtain the optimal fitness value for three suspension comfort indices. By comparing the results with those obtained from passive suspension and traditional LQR control of active suspension, optimizing the LQR control of active suspension based on the modified differential evolution algorithm can effectively reduce vehicle vibration amplitude while considering overall suspension performance enhancement, thereby significantly improving ride comfort and handling stability
Study on the mechanical characteristics and impact resistance improvement of substation masonry wall under flood load
Get PDFThis study examines the stress characteristics and deformation modes of masonry walls under flood loads in a 500kV substation project in Xinyang City, Henan Province. A simplified finite element model of substation masonry walls is developed in ABAQUS, considering dynamic water loads, the stress characteristics and deformation modes of masonry walls under flood loads are studied. Flood depth, water velocity, and erosion depth are selected as variables to carry out the parametric analysis of masonry enclosure walls under flood load, to investigate the dynamic response of walls under various parameters, and to examine the damage mechanism of the wall. The research findings suggest that stress levels are elevated at critical locations, such as the bottom center of the wall, the junction between the inner wall and structural column, and the connection between the foundation and structural column during flood loading. The safety of a masonry wall is significantly compromised when flood depth exceeds 0.8 m, water velocity exceeds 2.3 m/s, or erosion depth reaches 0.4 m. A proposed measure aims to enhance the performance of masonry walls by improving stress distribution and reducing stress concentrations, thereby significantly augmenting their load-bearing capacity
Treatment of unilateral posterior crossbite with Maurício Vaz de Lima appliance – case report
Get PDFPosterior crossbite (PCB) is a common malocclusion and its diagnosis must be careful, because only knowing its etiology can determine the treatment plan. The PCB can be dental, skeletal or functional. For each subtype, there is a specific treatment. The aim of this study was to report the treatment of two patients with Skeletal Unilateral Posterior Crossbite. The patients were treated with the same device, a Maurício expander with a Hawley arch. The technique employed, following the Knowledge of Jaw Functional Orthopedics (JFO), proved to be extremely efficient, allowing correction of crossbite malocclusion, mandible centralization, correct dental positioning, restoring conditions so that the growth and development of the patients occurred in a correct and balanced way
Case report of 2-year-old child with congenital torticollis and crossbite treated with functional orthopedics of the jaws
Get PDFSatisfactory chewing is performed by an alternating bilateral pattern that depends on occlusal balance, the absence of occlusal interference or premature contacts, stability, good functioning of the temporomandibular joints (TMJs) and neuromuscular maturation. If mandibular functional imbalances occur, discrepancies in maxillomandibular development and future facial asymmetries may occur. The objective of this work was to remove dental interferences that cause anterior and posterior crossbite, as well as those that prevent the good execution of symmetrical lateroprotrusive movements (right side/left side), through occlusal adjustment and subsequent correction of maxillary asymmetry using the device; encapsulated. Clinical case report of a two-year-old female patient, with unilateral crossbite on the right side (anterior/posterior), diagnosed with congenital torticollis, difficulty breastfeeding and difficulty performing alternating lateral movements. with follow-up until the complete deciduous dentition. The treatment was divided into three stages. The first step was to correct the unilateral crossbite (anterior and posterior), on the right side, by making occlusal adjustment using a grid, and later with the addition of Planas Direct Tracks resin. The second stage used an encapsulated device to correct maxillary asymmetry. The third stage was completed after the eruption of the deciduous second molars with the functional analysis of lateral movements plus occlusal adjustments using a grid. Correction of unilateral crossbite (anterior and posterior) on the right side, symmetrization of the maxilla and better execution of lateroprotrusive movements. The results obtained in this case report suggest that the occlusal adjustment removed the dental interferences that caused the anterior/posterior crossbite on the right side; the maxilla was symmetrized with the distalization of sector 63-65, and the removal of dental interferences that prevented lateral movements made it possible to perform lateroprotrusive movements (right/left side) after the complete eruption of the primary teeth
Assessing environmental influences on radon levels: analysis of independent variables
Get PDFRegression analysis is essential for prediction analysis and variable identification since air pollution studies are complicated by competing suggestions and require careful interpretation. In the existing predictive analysis, estimating indoor radon levels is challenging due to multicollinearity issues and the existing algorithm's assumption of independent predictor variables, making it difficult to accurately assess individual effects. Hence a novel Unsupervised Bayesian Multiple Regression Analysis is used to correctly offer the specific impacts of each predictor variable by taking the complex interactions between factors in the estimation of indoor radon levels. Furthermore, in the variable identification, indoor radon levels are influenced by complex residual distributions, with existing algorithms failing to predict non-Gaussian residuals due to outlier-sensitive least squares estimation. So a novel Quadratic Discriminant Extreme Learning Machine is implemented to overcome this issue, which creates models that are better able to reliably detect the factors driving indoor radon levels and are more robust to non-Gaussian residual distributions. The proposed method demonstrates excellence in predictive analysis and variable identification achieving high coefficient of relation and low MAE
Prestressed concrete continuous bridge girders: comparison of the Chinese and Southern African codes
Get PDFTo provide a reference for designers, taking a 30 m + 40 m + 30 m prestressed concrete continuous beam bridge as an example, this paper compares the differences between Chinese Codes and Southern African Codes in terms of load effect, prestressing requirements and design safety. The results show that the actual number of prestressed strands required by the Southern African Code in the mid-span section is 11.63 %-12.50 % larger than that required by the Chinese Code. The actual number of prestressed strands required by the Southern African Code in the fulcrum section is 16.33 %-30.00 % lower than that required by the Chinese Code. The safety margin factor of the section designed by the Southern African Code is higher than that of the Chinese Code, and has a higher safety reserve