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Table of Content

      
    20 September 2020
    Volume 55 Issue 9
    Bifurcation analysis and control of HR neuron model under electromagnetic induction
    QIAO Shuai, AN Xin-lei, WANG Hong-mei, ZHANG Wei
    JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE). 2020, 55(9):  1-9.  doi:10.6040/j.issn.1671-9352.0.2019.634
    Abstract ( 200 )   PDF (2693KB) ( 261 )   Save
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    It is of great value to study the firing activity of neurons under electromagnetic radiation for the control and treatment of neuron-related lesions. Based on the theoretical analysis and numerical simulation, the bifurcation structure of HR neuron model of magnetic flux and its stability control of subcritical Hopf bifurcation are studied. Through the numerical simulation, it is found that the system has alternations of plus period 1 bifurcation, double period bifurcation and chaos in the two-parameter region. In addition, through the theoretical analysis of distribution and stability of the system equilibrium point under the change of external stimulus current, it is concluded that there exists a supercritical Hopf bifurcation point in the system, and a hidden limit cycle attractor is found near the subcritical Hopf bifurcation point. By using Washout controller, the subcritical Hopf bifurcation stability control is realized, which eliminates the phenomenon of hidden discharge and helps reveal and understand the internal mechanism of the generation and transformation of hidden discharge in neurons.
    Bifurcation analysis and synchronous control of e-HR neuron model
    WANG Hong-mei, AN Xin-lei, QIAO Shuai, ZHANG Wei
    JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE). 2020, 55(9):  10-18.  doi:10.6040/j.issn.1671-9352.0.2019.795
    Abstract ( 163 )   PDF (7327KB) ( 46 )   Save
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    On the generalized distance spectrum of graphs
    LU Peng-li, LIU Wen-zhi
    JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE). 2020, 55(9):  19-28.  doi:10.6040/j.issn.1671-9352.0.2019.766
    Abstract ( 184 )   PDF (448KB) ( 105 )   Save
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    The upper and lower bounds of the generalized distance spectral radius of G and of its line graph L(G)are obtained, based on some graph parameters, and the extremal graphs are determined. Then, the generalized distance spectrum of some composite graphs is calculated.
    Neighbor sum distinguishing edge coloring of the join of paths
    TIAN Shuang-liang, YANG Huan, YANG Qing, SUOLANG Wang-qing
    JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE). 2020, 55(9):  29-35.  doi:10.6040/j.issn.1671-9352.0.2018.144
    Abstract ( 153 )   PDF (377KB) ( 44 )   Save
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    A proper [k]-edge coloring σ of a graph G is a k-proper-edge-coloring of G using colors in [k]={1,2,…,k}, let wσ(x)denote the sum of the colors of edges incident with x, i.e., wσ(x)=∑e??綍xσ(e), and wσ(x)is called the weight of the vertex x with respect to σ. A neighbor sum distinguishing edge coloring σ of G is a proper [k]-edge coloring of G such that no pair adjacent vertices receive the same weight. The smallest value k for which G has such a coloring is called the neighbor sum distinguishing edge chromatic number of G and denoted by χ'(G). The exact values of the neighbor sum distinguishing edge chromatic number of the join of two paths with different orders are given. The upper bound of the neighbor sum distinguishing edge chromatic number of the join of two paths with same orders is obtained.
    Adjacent vertex distinguishing edge coloring of planar graphs without intersecting triangles
    LIU Zhuo-ya, XU Chang-qing
    JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE). 2020, 55(9):  36-41.  doi:10.6040/j.issn.1671-9352.0.2019.610
    Abstract ( 212 )   PDF (453KB) ( 69 )   Save
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    A k-adjacent vertex distinguishing edge coloring of a graph G is a proper k-edge coloring of G such that for any two adjacent vertices u and v, the color set of edges incident with u is different from the color set of edges incident with v. The least k for a k-adjacent vertex distinguishing edge coloring of G is the adjacent vertex distinguishing chromatic number, denoted by χ'a(G). By using the discharging method, we study the adjacent vertex distinguishing chromatic number of a planar graph without intersecting triangles, and get the conclusion: if G is a planar graph without intersecting triangles, then χ'a(G)≤max{Δ(G)+2,10}.
    Edge-magic total labeling of unicyclic graphs
    WANG Bi-mei, LI Jing-wen, GU Yan-bo, SHAO Shu-hong
    JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE). 2020, 55(9):  42-50.  doi:10.6040/j.issn.1671-9352.0.2019.439
    Abstract ( 196 )   PDF (741KB) ( 72 )   Save
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    An edge-magic total labeling is a one-to-one mapping f from V(G)∪E(G) onto {1,2,…,p+q} such that there exists a constant K satisfying f(u)+f(v)+f(uv)=K, for each uv∈E(G). A graph G(p,q) which has a edge-magic total labeling can be called edge-magic total labeling graph. An algorithm to label the unicyclic graphs with less than 16 vertices is designed. The rules of two special unicyclic graphs are obtained, and CnSymbolQC@Sm and CnΔSm to describe the two types of graphs are defiened, and related theorems are given and proved. The results show that all the unicyclic graphs with less than or equal to 16 vertices have a edge-magic total labeling, and most of them are super edge-magic total labeling. Therefore, it is speculated that the unicyclic graphs with more than 16 vertices also have the same characters.
    Vertex-disjoint triangles in anti-d-degenerate graphs
    NIU Bei, ZHANG Xin
    JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE). 2020, 55(9):  51-53.  doi:10.6040/j.issn.1671-9352.0.2019.089
    Abstract ( 143 )   PDF (324KB) ( 74 )   Save
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    A graph G is an anti-d-degenerate graph if its complement graph (-overG) is a d-degenerate graph. It is proved that every anti-d-degenerate graph G with |G|=3k and δ(G)≥k≥26d contains k vertex-disjoint triangles, where d≥2.
     
    A high-performance FPGA-based implementation method of SM9
    Qiu-liang XU
    JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE). 2020, 55(9):  54-61.  doi:10.6040/j.issn.1671-9352.0.2020.322
    Abstract ( 224 )   HTML ( 12 )   PDF (10423KB) ( 121 )   Save
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    In order to improve the performance of SM9, this paper uses the fixed-base comb method for modular exponentiation in SM9, which is verified on the Xilinx's Kintex-7 FPGA platform. The experimental results show that this work can improve the performance of SM9 signature by 2.3 times, and facilitate the large-scale popularization of SM9 algorithm.

    Detection method of hemorrhages of fundus image based on deep learning
    Wen-she YIN,Jian-feng HE
    JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE). 2020, 55(9):  62-71.  doi:10.6040/j.issn.1671-9352.0.2019.475
    Abstract ( 222 )   HTML ( 6 )   PDF (8260KB) ( 63 )   Save
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    This paper proposes a method for detecting the bleeding point of fundus images based on convolutional neural networks (CNN) plus conditional random fields (CRF). First, in order to avoid the influence of the background area of the image on subsequent detection, refer to the gray level information in the fundus image and adjust the image to the appropriate size according to the length of the fundus center to its edge, and then linearly weight the image to enhance its brightness and contrast; then, using the cropped image block to train the CNN model for detecting the bleeding point on the CNN architecture built on the VGG network; finally, to overcome the problems of false detection and missed detection in the bleeding point detection of the CNN model, CRF is used for CNN. The probability map of the model output is post-processed to achieve accurate detection of the bleeding point of the fundus image. The detection method proposed in this paper was trained and verified on the open Kaggle and Messidor databases, and achieved 98.8% accuracy, 99.4% recall rate and 99.1% F-score. In addition, the sensitivity tested on the DIARETDB1 database reached 98.5% and the F-score was 96.1%. The experimental results show that the effectiveness and superiority of the proposed method are illustrated from both image visual and quantitative detection.

    Low-light image enhancement algorithm based on variational structure
    Ming-xing LIN
    JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE). 2020, 55(9):  72-80.  doi:10.6040/j.issn.1671-9352.0.2020.202
    Abstract ( 183 )   HTML ( 8 )   PDF (24083KB) ( 53 )   Save
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    Aiming at the problem that the images captured under low illumination present some defects, such as low brightness and poor visibility, a low-light image enhancement algorithm based on variational structure guided filtering is proposed. First, the maximum of R, G and B channels are searched at each pixel of the input image, and the bright channel map is obtained by using the maximum filtering. Secondly, a novel guided filtering based on variational model is constructed to refine the bright channel image to estimate the illumination component. Subsequently, the reflection component is obtained by removing the illumination component according to the Retinex model. Finally, homomorphic filtering and linear stretching are employed to further improve the contrast of the reflection component to output an enhanced image with clear visibility. Comprehensive experimental results show that this algorithm can effectively and quickly enhance the illumination and contrast of low-light images and retain details.

    Net premium reserve in life insurance under Vasicek model with jumps
    Chun-yan SONG,Shi-long LI
    JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE). 2020, 55(9):  81-88.  doi:10.6040/j.issn.1671-9352.0.2019.700
    Abstract ( 178 )   HTML ( 6 )   PDF (947KB) ( 49 )   Save
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    Considering the characteristics of random volatility with jumps of market interest rates, both compound Poisson process and Ornstein-Uhlenbeck process are utilized to describe the stochastic jumps and random continuous changes of interest rates respectively. A Vasicek interest model with Poisson jumps is obtained by coupling the two kinds of stochastic processes. The mathematical expressions of the cumulative interest force function and the expected discount function of money under the model are studied. At the same time, the corresponding numerical analysis is given. Based on this interest model, the calculation of the net premium reserves of life insurance products is further studied

    Dynamic quality improvement strategies with delay effect in consumer reference quality
    De-qing MA,Jin-song HU
    JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE). 2020, 55(9):  101-89.  doi:10.6040/j.issn.1671-9352.0.2019.190
    Abstract ( 162 )   HTML ( 6 )   PDF (1479KB) ( 64 )   Save
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    Considering the delay effect of manufacturer product improvement on consumer reference quality, the supply chain differential game models of Nash non-cooperative game, cooperative game, partial cooperative game for manufacturer to bear retailer advertising cost and partial cooperative game for retailer to bear manufacturer quality cost are constructed. The member equilibrium strategy and supply chain performance of four game modes are obtained with the help of differential game theory. It is found that the delay effect will affect the quality improvement strategy of the manufacturer, but will not affect the advertising strategy of the retailer. The marginal revenue and cost of the members are the key factors affecting the strategy and performance. The results of comparative analysis and numerical examples show that partial cooperative games of supply chain members can not realize the perfect coordination of supply chain, but it can improve the decentralized supply chain in Pareto. The strategies members performance and consumer reference quality level under cooperative games are higher with or without the delay effect.

    Pathological study on infection of Vibrio anguillarum and Vibrio parahemolyticus to Octopus ocellatus
    Yan-wei FENG,Zan LI,Wei-jun WANG,Guo-hua SUN,Guo-hua SUN,Xiao-hui XU
    JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE). 2020, 55(9):  102-110.  doi:10.6040/j.issn.1671-9352.0.2019.834
    Abstract ( 178 )   HTML ( 8 )   PDF (24826KB) ( 22 )   Save
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    In order to control aquaculture diseases and understand the influence of pathogen microorganisms on cephalopoda culture, we selected vibrio with high incidence in seawater culture, including V.anguillarum and V.parahemolyticus, to study their virulence level and pathogenic mechanism against shortarm octopus. Through direct injection of diluted bacteria solution into shortarm octopus carpus arm, the death rate and half lethal time of shortarm octopus after infection were observed, as well as the effects of various bacteria on the structures of shortarm octopus liver, gill, gill heart and white body. The results showed that V.anguillarum and V.parahemolyticus were both highly pathogenic to shortarm octopus, reaching a semi-fatality rate at 60 h and 48 h, respectively. In addition, the activity of octopus was decreased, weakness and abdominal swelling were observed; Through the observation of paraffin sections and HE staining and ultramicroscopic structure of diseased and healthy tissues, it was found that the liver, gill, gill heart and white body of the diseased octopus showed different degrees of tissue or cell structure damage. The above results indicated that both V.anguillarum and V.parahemolyticus were significantly pathogenic to shortarm octopus, and the pathogenicity of V.parahaemolyticus might be stronger, which would be one of the greatest threats of shortarm octopus large-scale farming if the conditions were suitable.