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[Author] Guoxing ZHANG(3hit)

1-3hit
  • Predicting Taxi Destination by Regularized RNN with SDZ

    Lei ZHANG  Guoxing ZHANG  Zhizheng LIANG  Qingfu FAN  Yadong LI  

     
    LETTER-Data Engineering, Web Information Systems

      Pubricized:
    2018/05/02
      Vol:
    E101-D No:8
      Page(s):
    2141-2144

    The traditional Markov prediction methods of the taxi destination rely only on the previous 2 to 3 GPS points. They negelect long-term dependencies within a taxi trajectory. We adopt a Recurrent Neural Network (RNN) to explore the long-term dependencies to predict the taxi destination as the multiple hidden layers of RNN can store these dependencies. However, the hidden layers of RNN are very sensitive to small perturbations to reduce the prediction accuracy when the amount of taxi trajectories is increasing. In order to improve the prediction accuracy of taxi destination and reduce the training time, we embed suprisal-driven zoneout (SDZ) to RNN, hence a taxi destination prediction method by regularized RNN with SDZ (TDPRS). SDZ can not only improve the robustness of TDPRS, but also reduce the training time by adopting partial update of parameters instead of a full update. Experiments with a Porto taxi trajectory data show that TDPRS improves the prediction accuracy by 12% compared to RNN prediction method in literature[4]. At the same time, the prediction time is reduced by 7%.

  • Fast Time-Aware Sparse Trajectories Prediction with Tensor Factorization

    Lei ZHANG  Qingfu FAN  Guoxing ZHANG  Zhizheng LIANG  

     
    LETTER-Data Engineering, Web Information Systems

      Pubricized:
    2018/04/13
      Vol:
    E101-D No:7
      Page(s):
    1959-1962

    Existing trajectory prediction methods suffer from the “data sparsity” and neglect “time awareness”, which leads to low accuracy. Aiming to the problem, we propose a fast time-aware sparse trajectories prediction with tensor factorization method (TSTP-TF). Firstly, we do trajectory synthesis based on trajectory entropy and put synthesized trajectories into the original trajectory space. It resolves the sparse problem of trajectory data and makes the new trajectory space more reliable. Then, we introduce multidimensional tensor modeling into Markov model to add the time dimension. Tensor factorization is adopted to infer the missing regions transition probabilities to further solve the problem of data sparsity. Due to the scale of the tensor, we design a divide and conquer tensor factorization model to reduce memory consumption and speed up decomposition. Experiments with real dataset show that TSTP-TF improves prediction accuracy generally by as much as 9% and 2% compared to the Baseline algorithm and ESTP-MF algorithm, respectively.

  • Entropy-Based Sparse Trajectories Prediction Enhanced by Matrix Factorization

    Lei ZHANG  Qingfu FAN  Wen LI  Zhizhen LIANG  Guoxing ZHANG  Tongyang LUO  

     
    LETTER-Data Engineering, Web Information Systems

      Pubricized:
    2017/06/05
      Vol:
    E100-D No:9
      Page(s):
    2215-2218

    Existing moving object's trajectory prediction algorithms suffer from the data sparsity problem, which affects the accuracy of the trajectory prediction. Aiming to the problem, we present an Entropy-based Sparse Trajectories Prediction method enhanced by Matrix Factorization (ESTP-MF). Firstly, we do trajectory synthesis based on trajectory entropy and put synthesized trajectories into the trajectory space. It can resolve the sparse problem of trajectory data and make the new trajectory space more reliable. Secondly, under the new trajectory space, we introduce matrix factorization into Markov models to improve the sparse trajectory prediction. It uses matrix factorization to infer transition probabilities of the missing regions in terms of corresponding existing elements in the transition probability matrix. It aims to further solve the problem of data sparsity. Experiments with a real trajectory dataset show that ESTP-MF generally improves prediction accuracy by as much as 6% and 4% compared to the SubSyn algorithm and STP-EE algorithm respectively.