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[Author] Li TAN(6hit)

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  • Automated 3D Measurement of Shape and Strain Distribution Using Fourier Transform Grid Method

    Yoshiharu MORIMOTO  Li TANG  Yasuyuki SEGUCHI  

     
    PAPER

      Vol:
    E74-D No:10
      Page(s):
    3459-3466

    The Fourier transform grid methos (FTGM) had been proposed previously by the authors for measuring in-plane strain distibution. In this paper, two automated grid methods are proposed using the FTGM. One is a method for measuring the shape of the full surface of a cylindrical object. A new forming grid method is proposed for introducing the FTGM into the slit projection method. In order to measure the full surface of the object, the object is rotated by a constant angle, the projected line is recorded and the line image is shifted by a constant number of pixels. The next recorded projected line is superimposed in the same image memory. By repeating the above operation, a grating image is formed in the image memory. The formed grating iemage is precisely analyzed at once by the FTGM. The other is a shape and strain measurement method for a curved plate. In the conventional automated grid method, because the position of a grid point is exprssed by an integer number of pixels, it is difficult to use for accurate measurement. Using the FTGM, the position of the grating is measured by the decimal number of pixels by analyzing the phase distribution. The accuracy is higher. Moreover, since each pixel point has a phase, matching for corresponding points between different images is easily performed by comparing the phases of the points. Two applications for medical and mechanical experiments are presented.

  • An Iterative Factorization Method Based on Rank 1 for Projective Structure and Motion

    Shigang LIU  Chengke WU  Li TANG  Jing JIA  

     
    PAPER-Image Recognition, Computer Vision

      Vol:
    E88-D No:9
      Page(s):
    2183-2188

    We propose a method for the recovery of projective structure and motion by the factorization of the rank 1 matrix containing the images of all points in all views. In our method, the unknowns are the 3D motion and relative depths of the set of points, not their 3D positions. The coordinates of the points along the camera plane are given by their image positions in the first frame. The knowledge of the coordinates along the camera plane enables us to solve the SFM problem by iteratively factorizing the rank 1 matrix. This simplifies the decomposition compared with the SVD (Singular Value Decomposition). Experiments with both simulated and real data show that the method is efficient for the recovery of projective structure and motion.

  • A Weighted Voronoi Diagram-Based Self-Deployment Algorithm for Heterogeneous Directional Mobile Sensor Networks in Three-Dimensional Space

    Li TAN  Xiaojiang TANG  Anbar HUSSAIN  Haoyu WANG  

     
    PAPER-Network

      Pubricized:
    2019/11/21
      Vol:
    E103-B No:5
      Page(s):
    545-558

    To solve the problem of the self-deployment of heterogeneous directional wireless sensor networks in 3D space, this paper proposes a weighted Voronoi diagram-based self-deployment algorithm (3DV-HDDA) in 3D space. To improve the network coverage ratio of the monitoring area, the 3DV-HDDA algorithm uses the weighted Voronoi diagram to move the sensor nodes and introduces virtual boundary torque to rotate the sensor nodes, so that the sensor nodes can reach the optimal position. This work also includes an improvement algorithm (3DV-HDDA-I) based on the positions of the centralized sensor nodes. The difference between the 3DV-HDDA and the 3DV-HDDA-I algorithms is that in the latter the movement of the node is determined by both the weighted Voronoi graph and virtual force. Simulations show that compared to the virtual force algorithm and the unweighted Voronoi graph-based algorithm, the 3DV-HDDA and 3DV-HDDA-I algorithms effectively improve the network coverage ratio of the monitoring area. Compared to the virtual force algorithm, the 3DV-HDDA algorithm increases the coverage from 75.93% to 91.46% while the 3DV-HDDA-I algorithm increases coverage from 76.27% to 91.31%. When compared to the unweighted Voronoi graph-based algorithm, the 3DV-HDDA algorithm improves the coverage from 80.19% to 91.46% while the 3DV-HDDA-I algorithm improves the coverage from 72.25% to 91.31%. Further, the energy consumption of the proposed algorithms after 60 iterations is smaller than the energy consumption using a virtual force algorithm. Experimental results demonstrate the accuracy and effectiveness of the 3DV-HDDA and the 3DV-HDDA-I algorithms.

  • Improved LEACH-M Protocol for Processing Outlier Nodes in Aerial Sensor Networks

    Li TAN  Haoyu WANG  Xiaofeng LIAN  Jiaqi SHI  Minji WANG  

     
    PAPER-Network

      Pubricized:
    2020/11/05
      Vol:
    E104-B No:5
      Page(s):
    497-506

    As the nodes of AWSN (Aerial Wireless Sensor Networks) fly around, the network topology changes frequently with high energy consumption and high cluster head mortality, and some sensor nodes may fly away from the original cluster and interrupt network communication. To ensure the normal communication of the network, this paper proposes an improved LEACH-M protocol for aerial wireless sensor networks. The protocol is improved based on the traditional LEACH-M protocol and MCR protocol. A Cluster head selection method based on maximum energy and an efficient solution for outlier nodes is proposed to ensure that cluster heads can be replaced prior to their death and ensure outlier nodes re-home quickly and efficiently. The experiments show that, compared with the LEACH-M protocol and MCR protocol, the improved LEACH-M protocol performance is significantly optimized, increasing network data transmission efficiency, improving energy utilization, and extending network lifetime.

  • A Collaborative Filtering Recommendation Algorithm Based on Hierarchical Structure and Time Awareness

    Tinghuai MA  Limin GUO  Meili TANG  Yuan TIAN  Mznah AL-RODHAAN  Abdullah AL-DHELAAN  

     
    PAPER-Data Engineering, Web Information Systems

      Pubricized:
    2016/03/09
      Vol:
    E99-D No:6
      Page(s):
    1512-1520

    User-based and item-based collaborative filtering (CF) are two of the most important and popular techniques in recommender systems. Although they are widely used, there are still some limitations, such as not being well adapted to the sparsity of data sets, failure to consider the hierarchical structure of the items, and changes in users' interests when calculating the similarity of items. To overcome these shortcomings, we propose an evolutionary approach based on hierarchical structure for dynamic recommendation system named Hierarchical Temporal Collaborative Filtering (HTCF). The main contribution of the paper is displayed in the following two aspects. One is the exploration of hierarchical structure between items to improve similarity, and the other is the improvement of the prediction accuracy by utilizing a time weight function. A unique feature of our method is that it selects neighbors mainly based on hierarchical structure between items, which is more reliable than co-rated items utilized in traditional CF. To the best of our knowledge, there is little previous work on researching CF algorithm by combining object implicit or latent object-structure relations. The experimental results show that our method outperforms several current recommendation algorithms on recommendation accuracy (in terms of MAE).

  • Social Network and Tag Sources Based Augmenting Collaborative Recommender System

    Tinghuai MA  Jinjuan ZHOU  Meili TANG  Yuan TIAN  Abdullah AL-DHELAAN  Mznah AL-RODHAAN  Sungyoung LEE  

     
    PAPER-Office Information Systems, e-Business Modeling

      Pubricized:
    2014/12/26
      Vol:
    E98-D No:4
      Page(s):
    902-910

    Recommender systems, which provide users with recommendations of content suited to their needs, have received great attention in today's online business world. However, most recommendation approaches exploit only a single source of input data and suffer from the data sparsity problem and the cold start problem. To improve recommendation accuracy in this situation, additional sources of information, such as friend relationship and user-generated tags, should be incorporated in recommendation systems. In this paper, we revise the user-based collaborative filtering (CF) technique, and propose two recommendation approaches fusing user-generated tags and social relations in a novel way. In order to evaluate the performance of our approaches, we compare experimental results with two baseline methods: user-based CF and user-based CF with weighted friendship similarity using the real datasets (Last.fm and Movielens). Our experimental results show that our methods get higher accuracy. We also verify our methods in cold-start settings, and our methods achieve more precise recommendations than the compared approaches.