Grey Correlation Theory Research Articles

Sensitivity Analysis of Influencing Factors of Underground Civil Air Defense Construction Vibration under Vehicle Load

Grey correlation theory is an uncertainty analysis method, which can find the relevance of various factors studied through certain data processing in incomplete information and find the main influencing factors. In order to study the influence of vehicle load on the vibration of underground civil air defense construction, taking the civil air defense construction at the intersection of Zhongzhou Middle Road and Shachang South Road in Luoyang as the study subject, based on the field measured data, and using ANSYS to expand the working conditions, this paper studies the influence of such factors as elastic modulus of concrete, thickness of overburden layer, density of soil layer, elastic modulus of soil layer, vehicle speed, and vehicle mass on the vibration of the civil air defense construction through the grey correlation sensitivity analysis method. The field measurement and numerical simulation results show that the displacement, velocity, and acceleration values decrease gradually from the mid−span position of the roof to the wall. Displacement, velocity, and acceleration are important indexes for evaluating vibration. The grey correlation degree of the influencing factors of displacement and velocity from large to small is density of soil layer, vehicle mass, vehicle speed, elastic modulus of concrete, elastic modulus of soil layer, and thickness of overburden layer. The grey correlation degree of the influencing factors of acceleration from large to small is vehicle mass, layer of density of soil layer, vehicle speed, elastic modulus of concrete, elastic modulus of soil layer, and thickness of overburden layer. The grey correlation degree of soil layer density, vehicle mass and vehicle speed to displacement, velocity, and acceleration is 0.7951–0.9993, which indicates that their influence is significant. This study can provide reference for the design and construction of similar civil air defense constructions.

Influence of3Dprinting process parameters on the tribological properties of acrylic resin

AbstractThis article studied the mechanism of the influence of light‐curing 3D forming parameters of acrylic resin on its tribological and mechanical properties. A three‐factor hybrid orthogonal table was designed, that is, the three key process parameters of printing monolayer thickness (P), heat treatment (H), and ultraviolet curing treatment (U). The priority of three process parameters affecting tribological performance was studied based on Gray Correlation Theory. The results showed that the order of priority was P, U, and H. The tribological and mechanical properties of acrylic resin decreased with the increase of printing monolayer thickness, while the printing efficiency increased with the increase of the printing monolayer thickness. Based on Gray Correlation Theory, the “Wear Resistance Efficiency” (WRE) parameter was defined to comprehensively evaluate the wear resistance and printing efficiency of the samples. When the thickness of the printing monolayer was 30 μm, the comprehensive properties of the material reached the optimal value. The U increased the cross‐linking degree of the acrylic interlayer molecules, and the H reduced the residual stress generated during the printing of the samples. The research results provided data support for the application of 3D printing acrylic resin and its nanocomposites in the field of tribology.

Habitat quality assessment of wintering migratory birds in Poyang Lake National Nature Reserve based on InVEST model.

Poyang Lake National Nature Reserve (PLNNR) is an important resting place for wintering migratory birds on the East Asian-Australasian Flyway (EAAF). In recent years, due to human activities and climate change, the area of wetlands has shown a downward trend, and the number and habitat of wintering migratory birds have been threatened. It is urgent to evaluate the habitat quality of wintering migratory birds in PLNNR. Therefore, the InVEST model and landscape index were used to evaluate the habitat quality of wintering migratory birds, and the grey correlation theory was used to reveal the response of typical wintering migratory bird population to habitat quality. The results showed that the habitat quality of the PLNNR was still at a high level, but showed a downward trend, with the average index of habitat quality decreasing from 0.872 to 0.817. The area of the highest quality habitat decreased by 3394.92 hm2, the area of the lowest, low, and medium quality habitats increased by 3112.11 hm2, and the area of the high quality habitat remained stable. The lowest, low, and medium quality habitat expanded from the middle to the south of the PLNNR mainly because of the expansion of construction land and cultivated land. The area with deterioration in habitat quality was 10,477.53 hm2, mainly concentrated in the center and south of the PLNNR. The area with restoration in habitat quality was 6148.26 hm2, mainly concentrated in the Bang Lake and Dacha Lake. The area with no change in habitat quality remained stable. The fragmentation degree and shape complexity of highest and high quality habitats increased, dominance degree and connectivity decreased, and the landscape pattern of habitat quality showed a downward trend. Typical wintering migratory birds have a strong correlation with highest, high, and low habitat quality, and there is a downward trend with the deterioration of habitat quality. Finally, this paper puts forward constructive suggestions on the degradation of habitat quality caused by land-use change.

The Quality Evaluation and Knowledge System Construction of Hierarchical Teaching in the Curriculum Are Based on the Grey Association Method

Based on the theory of grey correlation, the hierarchical teaching quality evaluation and knowledge system structure of the curriculum are established. Using the optimal clustering method, the teaching quality assessment and knowledge system construction at the curriculum level were obtained, and the grey correlation method was used to study the teaching at the course level. Through the evaluation of the discipline level and the discipline level and the construction of the knowledge system, the evaluation of the discipline level and the construction of the discipline knowledge system are achieved. The study found that the correlation between the curriculum grading teaching and the establishment of the knowledge system using the grey correlation method was higher than 0.900, the evaluation and knowledge system of the curriculum grading teaching were better evaluated, and the selection and retesting of evaluation indicators exceeded 0.700.

Effect of loading rate and height–diameter ratio on compression characteristics of aviation alloys

Loading rate and height–diameter ratio are important factors affecting mechanical properties of materials. In this paper, the effects of the two factors on the stress–strain curves and section deformation characteristics of titanium alloy and aluminum alloy were compared by uniaxial compression tests. The gray correlation coefficient between compressive strength and loading rate, height–diameter ratio, and high compression ratio of the two alloys was calculated by using the gray correlation theory, and multiple regression models of compressive strength of the two alloys were established based on the least squares method. The results show that ( i) the gray correlation coefficient of the two alloys is greater than 0.6, indicating that loading rate and height–diameter ratio have obvious effects on the compressive strengths of aluminum alloy; ( ii) of loading rate and height–diameter ratio, loading rate has more significant effect on compressive strength; and ( iii) the correlation coefficient of the regression model of titanium alloy compressive strength is 0.9, which is higher than that of the corresponding model of aluminum alloy (0.65), indicating that the reliability of the regression model of titanium alloy is higher than that of aluminum alloy, and the established model can better predict the uniaxial compressive strength of titanium alloy.

Research on structural parameter optimization of elliptical bipolar linear shaped charge based on machine learning

Numerical simulation based on SPH method, compared with laboratory experiments, using the grey correlation theory to analyze the correlation between the parameters of the elliptical bipolar linear shaped charge and the performance of the shaped charge jet. The structure of shaped charge is optimized by machine learning to obtain the optimal structural parameters, and it is compared with the rock crack development of shaped charge blasting in practical application. The results show that the structural parameters of the shaped charge have the same influence on the jet head velocity, and there are certain differences in the impact on the jet length. The fitted curve of the support vector machine (SVM) regression model based on the genetic algorithm (GA) is high prediction accurate. By comparing the optimization results with the actual engineering application of the shaped charge structure, the rock breaking effect has been significantly improved, which has important guiding significance for the actual engineering application.

Analysis of Uniaxial Compression Mechanical Properties of Rubber Powder Recycled Coarse Aggregate Concrete Based on Strain Energy Theory

In order to develop and make full use of waste construction concrete and waste tyre rubber powder, the experiment entirely used recycled coarse aggregate to replace natural crushed stone aggregate and investigated the effect of different mesh sizes of rubber powder (20 mesh, 60 mesh, and 100 mesh) on the uniaxial compressive mechanical properties, strain energy density, and pore structure of recycled coarse aggregate concrete at three curing ages (14 d, 28 d, and 90 d). Based on the strain energy theory, fractal theory, and grey correlation theory, the effects of the fractal dimension of the pore size of the rubber powder recycled concrete on the correlation of the strain energy parameters were investigated at different curing ages. The research results show that as the age period increases, the ability of the rubber powder recycled coarse aggregate concrete to absorb strain energy increases. Before the peak stress, the rubber powder recycled coarse aggregate concrete mainly carries out the storage of elastic strain energy. The incorporation of rubber powder can refine the pore structure of the rubber powder recycled coarse aggregate concrete so that the large pore size pores evolve towards the medium (50–200 μm) or small pores (<50 μm). The fractal dimension analysis revealed that the incorporation of 20 mesh and 60 mesh rubber powder enhances the inhomogeneity of the small pore (<50 μm) and the medium pore (40 μm–140 μm) in the recycled concrete. The grey correlation analysis revealed that the pore size factor with the greatest influence on the elastic energy density was the large pore size (>200 μm).

An Optimization of a Turbocharger Blade Based on Fluid–Structure Interaction

The structural fracture of the compressor blade is the main cause of fatigue failure. The novelty of this paper is the creative application of bent swept-back modeling to the blade of the turbocharger impeller. This paper is based on a compressor impeller satisfying the k-ε turbulence model. A simulation model was established in ANSYS software, the fluid–structure interaction was calculated in the three models before and after improvement, and the results were compared and analyzed. The optimized blade could improve the blade structure, reduce stress and deformation, and improve the pressurization ratio. In this paper, the optimization scheme of different parameters was discussed in line with the optimal solution. Based on the combination of fuzzy and grey correlation theory, it was concluded that the correlation between pressure and total deformation was higher than that of equivalent stress, and these two values reached 0.8596 and 0.8001, respectively. The results showed that the pressure and total deformation were significantly related to the flow rate. It provides a feasible scheme for further improvement of the supercharger compressor.

A Proposed Diagnostic Procedure for DC Electrical Tree Damage in XLPE

The growth and partial discharge (PD) characteristics of electrical tree in crosslinked polyethylene (XLPE) needle-plate electrode samples are investigated under constant dc voltage at different temperatures. The results reveal that under the experimental conditions, the electrical trees are all branch trees, and the discharge intensity fluctuates with time. The increase in temperature promotes the growth of electrical tree as well as the intensity of PD. Five texture features of PD <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${q}$ </tex-math></inline-formula> - <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${t}$ </tex-math></inline-formula> histogram are extracted and used as the elements to evaluate the insulation status of XLPE needle-plate electrode under dc voltage based on the gray correlation degree. The area ratio and lateral tree ratio of electrical tree is extracted based on the gray histogram. The lateral tree ratio increases with the increase in temperature, which is closely related to the intensity of PD. Gray correlation theory is used to evaluate the status of XLPE insulation. The results reveal that the evaluated insulation statuses based on the gray correlation degree are the same as those based on experience, which indicates that the proposed diagnosis method of XLPE insulation status based on the gray correlation degree with <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${q}$ </tex-math></inline-formula> - <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${t}$ </tex-math></inline-formula> histogram texture features as elements has a high accuracy.

Analysis of the drainage characteristics of different graded asphalt mixtures

ABSTRACT This study investigates the drainage characteristics of different asphalt mixtures in different directions using a new selfmade water seepage test device. Among them, the pavement drainage characteristics of five aggregate gradations were analyzed, which include asphalt concrete (AC-20), stone matrix asphalt (SMA-20), SUPAVE (SUP-20), and open-graded frictional course (OGFC-13 and OGFC-16). In addition, the effect of the void ratio on the drainage characteristics of different asphalt mixtures was analyzed based on the results of the permeability test. Finally, the gray correlation theory was applied to rate the relationship between different sieve passage rates and drainage properties of asphalt mixtures. The results of the study show that the transverse flow is larger than the longitudinal flow and plays a major role in the drainage process. The water volume is negatively correlated with the permeability coefficient of variation (CV). In addition, the permeability CV in all directions shows a gradual decrease with the increase of the permeability coefficient.

Laboratory investigation on influence of mixture parameters on noise reduction characteristics of porous asphalt concrete

ABSTRACT To investigate the influence of PAC mixture type and parameters on noise reduction performance and their variation patterns. This study investigated: the mixes’ gradation characteristics parameters, the coefficient of uniformity (CU) and coefficient of curvature (CC); the nominal maximum size (DT), the material’s composition parameter; the void ratio (VV) and thickness (H), the mixes’ structural composition parameters, and finally, the surface density (BD). PAC specimens’ sound absorption coefficient was measured indoors by the standing wave tube method, and the variation law were observed under different PAC parameters. PAC parameters’ degree of influence on noise reduction performance was investigated through grey correlation theory and correlation analysis. The results indicated that increasing the void ratio and thickness improved the peak absorption coefficient and enhanced PAC’s noise reduction performance effectively. Increasing the nominal maximum particle size weakened the noise reduction performance. In addition, the mix type and thickness had a greater influence on the basic trend in the absorption coefficient spectrogram. PAC’s noise reduction effect was reflected primarily in the middle and high frequency band, and moved to the high frequency band gradually as the thickness increased. Overall, VV, H, and DT had a relatively large effect on PAC’s noise reduction performance.

Analysis and Application of Vibration Damping Hole in Tunnel Working Face Based on Grey Correlation Analysis

In the process of tunnel blasting construction, certain vibration hazards will be caused to adjacent buildings. Therefore, it is necessary to explore feasible vibration reduction measures in the construction process. Combined with field measurement and numerical calculation, the law of vibration reduction effect of vibration reduction holes in the blasting construction of subway tunnels is analyzed. The gray correlation theory is used to determine the influence degree of vibration reduction hole parameters on the vibration reduction effect; each parameter is clarified, and the primary and secondary relationship of each parameter in the vibration reduction effect is clarified. Among them, the effect of damping hole spacing is particularly obvious. Combined with numerical calculation and comprehensive analysis of on-site construction effects, it is found that during the construction process, the distance between the vibration damping holes is 120 mm, the distance between the vibration damping holes and the explosion source is 2000 mm, the diameter of the vibration damping holes is more than 120 mm, the depth of the vibration damping holes is 1200–1500 mm, and double-row vibration-damping hole spacing is 50–100 mm, which can achieve a better vibration-damping effect. The research results will provide a reference vibration reduction technology for the blasting construction of urban shallow tunnels and have certain reference value and guiding significance for the blasting scheme design and vibration control of similar projects.

Day-Ahead Spot Market Price Forecast Based on a Hybrid Extreme Learning Machine Technique: A Case Study in China

With the deepening of China’s electricity spot market construction, spot market price prediction is the basis for making reasonable quotation strategies. This paper proposes a day-ahead spot market price forecast based on a hybrid extreme learning machine technology. Firstly, the trading center’s information is examined using the Spearman correlation coefficient to eliminate characteristics that have a weak link with the price of power. Secondly, a similar day-screening model with weighted grey correlation degree is constructed based on the grey correlation theory (GRA) to exclude superfluous samples. Thirdly, the regularized limit learning machine (RELM) is tuned using the Marine Predators Algorithm (MPA) to increase RELM parameter accuracy. Finally, the proposed forecasting model is applied to the Shanxi spot market, and other forecasting models and error computation methodologies are compared. The results demonstrate that the model suggested in this paper has a specific forecasting effect for power price forecasting technology.

Study on thermal resistance efficiency of open-graded frictional course pavements based on a laboratory simulated test

ABSTRACT The meso-structure of open-graded frictional course (OGFC) can significantly affect the heat transfer characteristics of the asphalt pavement. In this study, a laboratory simulation test device was developed to investigate the effect of aggregate gradations and void ratios on OGFC asphalt pavement heat transfer characteristics. Three aggregate gradations including asphalt concrete, stone mastic asphalt and OGFC were selected for pavement thermal resistance efficiency analysis. In addition, grey correlation theory was used to rate the relationship between different gradation ranges and thermal resistance efficiency. The test results show that this laboratory measurement device provides an effective method for estimating the thermal resistance of asphalt pavements. The OGFC asphalt mixture has the best thermal resistance performance compared to other grades. The air porosity and density have good linear relationship with the average temperature difference increment, and decreasing the density of the asphalt mixture or increasing the air voids content both increase the thermal resistance effect of the pavement.

Reliability allocation method of comprehensive weight computer numerical control machine tool based on failure correlation and factor correlation

AbstractAccording to the shortage of independent hypothesis allocation models between influence factors and subsystems, a reliability allocation method considering influence factor correlation and subsystem failure correlation is proposed. The CNC (Computer Numerical Control) machine tool is taken as the research object. Using Copula function to analyze failure correlation analysis between subsystems, establish subsystem complete reliability model and integrated importance measure model under failure correlation. The four factors of influencing reliability allocation are subsystem complexity, integrated importance measure of subsystem based on failure correlation, failure frequency, and specific gravity ratio of failure downtime. The correlation analysis among the influencing factors was carried out by using gray correlation theory, and the subjective weight of the subsystem was determined. The IEW‐VIKOR (Information Entropy Weight‐Vlsekriterijumska Optimizacija I Kompromisno Resenje) method is used to determine the objective weights of subsystems. The comprehensive weight of the subsystem is also obtained through combinatorial empowerment. The reliability allocation of the CNC machine tool subsystem was carried out according to the failure correlation reliability model, and the results of failure independence and failure correlation hypothesis allocation were compared and analyzed. When the reliability index is the same, the reliability allocation method proposed in this paper can assign lower reliability to each subsystem, which is of great significance to improve the reliability of CNC machine tools and reduce the difficulty of reliability design

Grey correlation analysis of milling temperature and milling vibration of TC4 titanium alloy

In this paper, a synchronous acquisition system of milling temperature and milling vibration was established to measure the data of milling temperature and milling vibration. Based on grey correlation theory, the influence of milling parameters and milling vibration on milling temperature was analyzed. It is found that the grey correlation degree between milling temperature and milling parameters and vibration is above 0.70, indicating that milling parameters and vibration have great influence on temperature. In addition, the GM (0, N) grey prediction model of milling temperature on milling parameters and milling vibration was established, and the correlation coefficient of the model was above 0.8, indicating that the reliability of the model was high, and the correlation between milling temperature and milling vibration signal was high.

Research on Evaluation Index of High Temperature Performance of Rubberized Asphalt Binder

The high-temperature rheological properties of rubberized asphalt and mixture were evaluated by frequency scanning, repeated creep recovery (RCR) test, temperature sweep test, Hamburg wheel tracking test (HWTT). Based on the Pearson correlation coefficient, the correlation of the mixture gradation and asphalt characteristics with the high-temperature stability of the mixture was analyzed. Finally, the gray correlation theory was applied to analyze the evaluation indexes of the high-temperature rheological properties of rubberized asphalt and mixture. The results show that the asphalt-stone ratio and the fractal dimension (Dc) of coarse aggregate have a significant correlation with the high-temperature performance of the mixture, and the mixture with a smaller asphalt-stone ratio and a higher percentage of coarse aggregate has a better high-temperature performance. The correlation degree of softening point, viscous stiffness modulus and permanent deformation with rubber-asphalt mixture is higher than 0.7, and are significantly higher than those of rotational viscosity at 180°C. Therefore, we recommend the use of permanent deformation, softening point, and viscous stiffness modulus to evaluate the high-temperature performance of rubberized asphalt mixture.

Research on the realization path of carbon emission reduction in Zhejiang Province

Zhejiang Province is a developed province in China. Over the years, the scale of economic development has been expanding. At the same time, Zhejiang province attaches great importance to reducing carbon emissions and has achieved remarkable results. Based on the grey correlation theory, this paper analyses the influencing factors of carbon emission in Zhejiang Province, and puts forward a series of suggestions for realizing carbon emission reduction in Zhejiang Province. The results show that the factors affecting carbon emissions in Zhejiang Province, in order of importance from high to low, are as follows:total population; total GDP; financial investment in education; financial investment in environmental protection and financial investment in science and technology. Therefore, in order to achieve the goal of carbon emission reduction in Zhejiang Province, we should focus on the following aspects: controlling the population and advocating green consumption; Improving the green growth level of local economy; increasing education expenditure to improve the people’s awareness of energy saving and environmental protection; increasing financial science and technology expenditure to develop advanced carbon emission reduction technology; Further increasing investment in environmental protection to purchase and configure more advanced environmental protection equipment.

To select suitable supplier for complex equipment military-civilian collaborative design based on fuzzy preference information that from matching perspective

Combine complex equipment collaborative development in military-civilian integration context not only fulfils actual development requirement, but also beneficial to the national economy. Design procedure as first stage of complex equipment military-civilian collaborative development process, select suitable design supplier is significant to whole development process of complex equipment. In order to select suitable design supplier for complex equipment, two aspects done in this paper. One is comprehensive analysis of evaluated influencing factors that affect complex equipment military-civilian collaborative design process, corresponding evaluation indicator constructed and a combination of grey correlation, entropy, DEMATEL (Decision-making Trial and Evaluation Laboratory) and VIKOR analysis theory to obtain grey entropy-DEMATEL-VIKOR, then the combined method is utilized to acquire matching attributes for followed research content. Meanwhile, satisfaction degree for matching side obtained with the help of information aggregation based on power generalized Heronian mean which on the basis of fuzzy preference information. Then, through constructed matching model, suitable design supplier obtained. Finally, a corresponding illustrative example given.

Fractional order time-delay multivariable discrete grey model for short-term online public opinion prediction

Aiming at the rapid fermentation characteristics of the online public opinion, this paper established the fractional order multivariable time-delayed discrete grey model to predict the trend of short-term online public opinion. Considering the dynamic time-varying delays of each driving factor in online public opinion, the time-delay parameters are introduced, and the lag time are determined by the maximum grey correlation theory. In order to reduce the influence of uncertainty between short-term public opinion data, the integer order accumulation is extended to the fractional order one, and the parameters are calculated by optimization model. Furthermore, the model is applied to forecast real event on microblog, and the results show that the new grey model has higher prediction accuracy compared with related grey models.