School of Mathematics and Statistics, Yancheng Teachers University, Yancheng, 224002, China (Received January 04 2019, accepted May 29 2019) In this paper, the dynamics and the finite-time synchronization of the delay hyperchaotic Lü system with disturbance are discussed. Based on the finite-time stability theory, a control law is put forward to realize finite-time chaos synchronization of the delay hyperchaotic Lü system with disturbance. Finally, numerical simulation results are provided to demonstrate the effectiveness and robustness of the proposed scheme.

School of Mathematics and Statistics, Nanjing University of Information Science & Technology, Nanjing, 210044, China (Received January 06 2019, accepted May 20 2019) In this article, we design and analyze a Galerkin finite element method (FEM) to solve the nonlinear Klein-Gordon equation in ?(? = 1,2,3) dimensions. The scheme is proved to preserve well the total energy in the discrete sense, which is consistent with the conservative property possessed by the original problem. Numerical results are reported to show the high accuracy of the numerical methods and confirm the energy conservation.

School of Mathematics and Statistics, NUIST, Nanjing, 210044, China (Received March 12 2019, accepted June 27 2019) In this paper, we give some equivalent conditions on when the fractions of rings can preserve Gorenstein flat modules.

School of Computing, University of Kent, CT2 7NZ, England, UK (Received May 10 2019, accepted June 11 2019) The tones of piano are produced by regular periodic oscillations and different keys’ individual inherent audio characteristics. Based on the collection of the sound wave signals and the analysis of the frequency characteristics from different keys, this study explores the methods to effectively identify and detect the corresponding numbers of keys. This paper will also compare and analyzed the different methods of audio signal extraction and identification of piano keys, to find effective methods to make theoretical preparation for further system development.

School of Mathematics and Statistics, Nanjing University of Information Science & Technology, Nanjing 210044, China (Received March 21 2019, accepted June 20 2019) Based on the air quality status of 161 cities in China, this paper studies the temporal and spatial distribution characteristics of PM2.5 concentration of major pollutants affecting air quality index (AQI). We use improved functional clustering analysis methods and add priori information about location and human factors to make the clustering results more accurate. The improved functional clustering model is compared with the basic sparse data function clustering method, k-centres functional clustering method, functional principal component analysis and traditional K-means clustering method by repeated simulation. Finally, we use the PM2.5 concentration of selected 161 cities in China as an illustrative example.

Jingji Zhao School of Mathematics and Statistics, Nanjing University of Information Science & Technology, Nanjing, 210044, China (Received May 11 2019, accepted July 20 2019) Existing content-based image retrieval methods exist some drawbacks, such as low retrieval precision, unstable performance. To address these drawbacks, in this paper a content-based image retrieval method is presented based on multi-feature fusion of principal component, oriented-gradient and color histogram. The idea for the proposed method is: firstly, input image is grayscale and flattened into a one- dimensional vector, and the first n principal components from the vector yielded by the PCA algorithm are extracted, in other word, input image is represented as a n×1 dimensional PCA feature vector. Secondly, to remedy color and orientation information missed by PCA, oriented-gradient and color histograms are used to extract orientation and color features respectively. Thirdly, extracted oriented-gradient and color histograms are merged with PCA features to generate the multi-feature representation of the input image. This paper confirms that the proposed multi-feature method can better represent an input image and can easily measure the similarity between images. The experiments are carried out and evaluated based on Corel-1000 , the target method is significantly better than the four popular methods.

1School of Mathematics and Statistics, Yancheng Teachers University, Yancheng, P.R. China 2 Computer and Information Engineering College, Hohai University, Nanjing, P.R. China (Received April 25 2019, accepted June 11 2019) In this paper, we investigate the color image encryption based on fractional-order memristive neuron system and DNA coding technology. The proposed encryption method consists of two stages: permutation and diffusion. Some numerical examples are exploited to demonstrate the feasibility of the encryption algorithm, and the security analysis shows that the algorithm has high security and good resistance to statistical attacks.

In this article, Shannon wavelet packets are studied together with their properties and focused the properties of packets through inner product.

School of Mathematics and Statistics, Nanjing University of Information Science & Technology, Nanjing, 210044, China (Received February 20 2019, accepted June 24 2019) Recognition of age and gender based on face image is one of the hotspots of current artificial intelligence research. In this paper, an improved VGG+SENet algorithm is proposed to simplify the identification of age and gender algorithm by simplifying VGGNet model, improving the loss function and embedding the SENet module. Compared with other models, the improved network structure and loss function model proposed in this paper can quickly and accurately obtain output recognition results. Experimental results on multiple benchmark face datasets show that the proposed improved VGG+SENet algorithm has higher recognition accuracy than other related models based on deep learning.

Anhui University of Technology, Anhui Maanshang 24300,China (Received April 01 2019, accepted June 07 2019) In view of the numerical calculation of zero-dimensional interior ballistics is not efficient for catapult interior ballistic engineers and it is difficult to simulate the flow field in the two-dimensional interior ballistic numerical simulation, combining with computer simulation technology, we build a gas-ejection interior ballistic simulation platform according to the idea of system structure. In this platform, the numerical simulation of gas-ejection interior trajectory is carried out from zero-dimensional and two-dimensional interior trajectory mathematical model. The simulation of interior ballistic flow field is accomplished by fluid mechanics software, and output the images of the interior trajectory characteristic parameter curve and temperature, velocity and pressure field. To help engineers to study the impact of structure parameters, material parameters and environmental coefficients on missile ejection. Through the use of military unit testing, the platform has been validated.