Applied Mechanics and Materials Vols. 713-715

Abstract: The mixture two-phase turbulence model and theory of particle dynamics is used to simulate the high concentration water-sand two-phase flow in a hydrocyclone. The article mainly analyzes the particle volumetric concentration distribution and separative efficiency of different diameter particles in a hydrocyclone. The simulation result shows that the particle volumetric concentration distribution of different diameter particles is nonuniform in a hydrocyclone. In the annular space, the small diameter particles are affected by the shortcut flow greatly and have high concentration near the wall of the overflow pipe, while the big diameter particles are mainly distributed near the wall in a hydrocyclone. In cylinder space and cone space, different-diameter particles show a similar distribution, the smaller-diameter particles mainly in inner vortex and the larger-diameter particles in outer vortex.

Abstract: With the modern economic and social development, economic research on fixed-asset investment has also become an important integral part. In this paper, Euler numerical approximation of the fixed assets model is given, and analysis proved the numerical solution of the model converges to its analytical solution.

Abstract: By using the AUTODYN, the study of numerical simulation on pressure field characteristics of underwater explosion detonated by the double explosive sources at the same time shows that a coupled zone with increased pressure appears after the two initial shock waves transmit through each other and at the intersection of the two initial shock waves, the mach wave appears. The transmitted waves diffract around bubbles with a reflected rarefaction wave. The peak pressure in the central area between the two explosive sources is caused by transmitted wave and has dishing isosurface. And the peak pressure outside the two explosive sources is caused by initial shock wave and has spherical isosurface. Coupled peak pressure in the plane of symmetry is two times more than incident peak pressure and with the propagation of shock wave, the ratio of coupled peak pressure and incident peak pressure gradually increases.

Abstract: For a population according to a uniform distribution where is known, Thomas Yageen (1996) derived an efficient estimator for . Here for the case when both and 'are unknown, we obtain uniformly minimum variance unbiased (UMVU) estimators for them. Moreover, for a sample drawn without replacement from an integer-valued population which is uniformly distributed on consecutive integers with both and unknown, we obtain a UMVU estimator for and apply it in a number serial analysis problem. Finally, under the criterion of mean squared error, one developed estimator is provided.

Abstract: Automatic orange quality classification based on computer image processing is accurate and efficient. In this paper, we discuss the orange feature extraction and description method based on image processing. Design an orange image edge detection method based on Canny operator, color characteristics description methods based on HIS model and shape characteristics description methods based on Fourier descriptor operator. The experiment result proof that Canny operator is high SNR,high accuracy and low computation;HIS model is more accord with human vision and low computation also; shape characteristics description methods based on Fourier descriptor operator is more easy to shape classification.

Abstract: K-means is a classic algorithm of clustering analysis and widely applied to various data mining fields. Traditional K-means algorithm selects the initial centroids randomly, so the clustering result will be affected by the noise points, and the clustering result is not stable. For this problem, this paper proposed a k-means algorithm based on density outlier detection. The algorithm firstly detected the outliers with the density model and avoided selecting outliers as the initial cluster centers. After clustering the non outlier, according to distance of the outlier to each centroids, the algorithm distributed the outliers to the corresponding clustering. The algorithm effectively reduced the influence of outliers to K-means and improved the accuracy of clustering result. The experimental result demonstrated that this algorithm can effectively improve the accurate rate and stability of the clustering.

Abstract: With the steady growth of the population in our country, the analysis of population is essential to the distribution of social resources and the improvement of the population quality. In this paper, we use the neural network of rational spline weight functions with cubic numerator and quadratic denominator to establish the model of Chinese population by four indicators, gender ratio, birth rate, elderly dependency ratio and natural increase rate. Finally we come to the conclusion through MATLAB simulation that the training speed is fast and the error is small. This kind of neural network can be applied to population analysis and it could be used in various fields.

Abstract: A Recursive Particle Swarm Optimization (RPSO) is proposed to solve dynamic optimization problems where the data is obtained not once but one by one. The position of each particle swarm is updated recursively based on the continuous data and the historical knowledge. The experiment results indicate that RPSO-based radial basis function networks needs fewer radial basis functions and gives more accurate results than traditional PSO in solving dynamic problems.

Abstract: BP algorithm is a classical neural network algorithm. We analyzed the deficiency of traditional BP neural network algorithm, designed new S function and momentum method strategy, optimized the algorithm parameters. We use the new algorithm in the classification of orange images, take color and shape features as input value, the experimental results proved that our algorithm is faster and the classification accuracy rate reaches to 90%

Abstract: With the purpose to overcome the numerical instabilities and to generate more distinct structural layouts in the topology optimization, by using bilinear interpolation function, a topology optimization model of density interpolation based on nodal density is established, smooth density field is constructed. This method can ensure that the density field in the fixed design domain owns C₀ continuity, and checkerboard patterns are naturally avoided in the nature of mathematics. After adding the sensitivity filtering, the optimal structures are smoother and have lesser details, which is helpful for manufacturing. Two numerical examples show that not only checkerboard pattern can be solved by the proposed method, but also the middle density nodal can be suppressed effectively.