The planning， deployment and optimization of mobile communication system networks all depend to varying degrees on the accuracy of the Reference Signal Receiving Power （RSRP） estimation. Traditionally， the RSRP of a signal receiver in a cell covered by a base station can be estimated by the corresponding wireless propagation model. In an urban environment， the wireless propagation models for different cells need to be calibrated using a large number of RSRP measurements. Due to the environment differences of different cells， the calibrated model is only applicable to the corresponding cell， and has low accuracy of RSRP estimation within the cell. To address these issues， the RSRP estimation problem was transformed into an image denoising problem and a cell-level wireless propagation model was obtained through image processing and deep learning techniques， which not only enabled RSRP estimation for the cell as a whole， but also was suitable to cells in similar environments. Firstly， the RSRP estimation map of the whole cell was obtained by predicting the RSRP of each receiver point by point through a random forest regressor. Then， the loss between the RSRP estimation map and the measured RSRP distribution map was regarded as the RSRP noise map， and a image denoising RSRP estimation method based on Conditional Generative Adversarial Network （CGAN） was proposed to reflect the environmental information of the cell through an electronic environmental map， which effectively reduced the RSRP of different cell. Experimental results show that the root mean square error of the proposed method is 6.77 dBm in predicting RSRP in a new cross-cell RSRP scenario without measured data， which is 2.55 dBm lower than that of the convolutional neural network-based RSRP estimation method EFsNet； in the same-cell RSRP prediction scenario， the number of model parameters is reduced by 80.3% compared with EFsNet.

Existing tree decoder is only suitable for solving single variable problems， but has no good effect of solving multivariate problems. At the same time， most mathematical solvers select truth expression wrongly， which leads to learning deviation occurred in training. Aiming at the above problems， a Graph to Equation Tree （GET） model based on expression level-by-level aggregation and dynamic selection was proposed. Firstly， text semantics was learned through the graph encoder. Then， subexpressions were obtained by aggregating quantities and unknown variables iteratively from bottom of the equation tree layer by layer. Finally， combined with the longest prefix of output expression， truth expression was selected dynamically to minimize the deviation. Experimental results show that the precision of proposed model reaches 83.10% on Math23K dataset， which is 5.70 percentage points higher than that of Graph to Tree （Graph2Tree） model. Therefore， the proposed model can be applied to solution of complex multivariate mathematical problems， and can reduce influence of learning deviation on experimental results.

In order to optimize the Energy Efficiency （EE） and Spectrum Efficiency （SE） of Decode-and-Forward （DF） full-duplex relay network， a trade-off method of EE and SE for DF full-duplex relay network was proposed. In full-duplex relay network， firstly， the EE of the network was optimized with the goal of improving the SE of the network. And the optimal power of the relay was obtained by combining the derivation and the Newton-Raphson method， then the Pareto optimal set of the objective function was given. Secondly， a trade-off factor was introduced through the weighted scalar method， a trade-off optimization function of EE and SE was constructed， and the multi-objective optimization problem of EE optimization and SE optimization was transformed into a single-objective energy-spectrum efficiency optimization problem by using normalization. At the same time， the performance of EE， SE and trade-off optimization under different trade-off factor was analyzed. Simulation results show that the SE and EE of the proposed method are higher at the same data transmission rate compared with the those of the full-duplex-optimal power method and the half-duplex-optimal relay-optimal power allocation method. By adjusting different trade-off factors， the optimal trade-off and the optimization of EE and SE can be achieved.

In view of the high computational complexity of opinion leader mining in social networks， an opinion leader recognition algorithm based on K-core decomposition， named CandidateRank （CR）， was proposed. Firstly， the opinion leader candidate set in a social network was obtained based on K-core decomposition method， so as to reduce the data size of opinion leader recognition. Then， a user similarity concept including location similarity and neighbor similarity was proposed， and the user similarity was calculated by K-core value， the number of entries， average K-core change rate and the number of user followers， and the global influence of the user in the candidate set was calculated according to the user similarity. Finally， opinion leaders were recognized by ranking users in the opinion leader candidate set by the global influence. In the experiment， two evaluation indexes of user influence predicted by Independent Cascade Model （ICM） and centrality were used to evaluate the opinion leader set selected by the proposed algorithm on three real datasets with different sizes. The results show that the proposed algorithm has the average user influence for the selected Top-15 users of 21.442， which is higher than those of the other three algorithms. In addition， compared to four K-core-related algorithms in correlation index， the results show that CandidateRank algorithm performs better in general. In summary， CandidateRank algorithm improves the accuracy while reducing the computational complexity.

The concept and architecture of the Internet of Things (IoT) were introduced. Key characteristics and technologies, which included the ubiquity of the IoT, intelligent identification and sensing technologies, uncertainty of data, representation methods of data, information propagation towards massive data, security and privacy were discussed in detail, and related open issues were presented. Based on the future ubiquitous applications, the research directions of the IoT were put forward.

In order to solve the problem of reduction anomaly in the existing probabilistic rough set models, non-parameterized and parameterized maximum decision entropy measures for attribute reduction were proposed by using the concept of maximum confidence of uncertain object. The monotonicity of the parameterized maximum decision entropy was explained and the relationship between its attribute reduction and other ones was analyzed. The definitions for core and relatively dispensable attributes in the proposed model were also given. Moreover, non-parameterized and parameterized confidence discernibility matrixes were put forward and the difference of classical discernibility matrix and the proposed ones in charactering the uncertain object were discussed. Finally, a case study was given to show the validity of the proposed model.