Aiming at the security communication problem of Heterogeneous Sensor Network (HSN), a secure group key management scheme W-LKH++ was proposed based on LKH++ tree. Firstly, as the wireless sensor nodes with low configuration, the initialization method for group key of LKH++ tree was modified to reduce the computationol overhead on each sensor node. Then, the holding way of keys were improved to reduce the storage overhead on each sensor node. Finally, a dynamic key updating method suitable for cluster head nodes was proposed to enhance the ability against node capture of the cluster head nodes based on low communication overhead, improving the security of communication of Wireless Sensor Network (WSN). Performance analysis and simulation results show that W-LKH++ improves the WSN security with low computation, storage and communication overhead.

In view of the problem that the existing researches do not consider the refinement of the factors affecting the network negative energy propagation and construct a propagation dynamics model for analysis, a Weak-Strong-Received-Infected-Evil (WSRIE) model of network negative energy propagation was proposed. Firstly, considering the difference of negative energy immunity and propagation ability of network users, the vulnerable states were divided into weak immunity and strong immunity, and the infectious states were divided into weak infection, strong infection and malicious propagation with unchanged scale. Secondly, according to the negative energy infection mechanism of the network, the state transition law was proposed. Finally, a dynamics model of network negative energy propagation for complex networks was constructed. The simulation comparison experiments on NW small world network and BA scale-free network were carried out. The simulation results show that under the same parameters, the weak immune node density of the NW network is 9 percentage points lower than that of the BA network, indicating that the network with small world characteristics is more susceptible to negative energy. In the BA network, the density of infected nodes with the malicious node degree of 200 is 5 percentage points higher than that with the node degree of 0, indicating that the greater the node degree of the network red opinion leader, the more network users affected by the network negative energy.

The effective planning and scheduling of the rescue operation plays an important role in saving lives and reducing property losses. Relying on mathematical modeling methods and computer simulation technology to assist decision-makers to complete the vehicle scheduling for emergency material distribution has become a consensus in the academic world. Focused on two key issues, i.e., model and optimization, the recent research status of the vehicle scheduling problem for emergency material distribution were analyzed. The main optimization objects and influence factors in the model of vehicle scheduling problem for emergency material distribution were reduced. The application effects of different optimization algorithms were compared and analyzed. And the existing problems of current research were brought forward. Finally, the future research trends of the vehicle scheduling for emergency material distribution were discussed.

Traditional automatic text summarization has generally no word count requirements while many social network platforms have word count limitation. Balanced performance is hardly obtained in short text summarization by traditional digest technology because of the limitation of word count. In view of this problem, a new automatic short text summarization method was proposed. Firstly, the values of relationship mapping, length mapping, title mapping and position mapping were calculated to respectively form some sets of candidate sentences. Secondly, the candidate sentences sets were mapped to abstract sentences set by multiple mapping strategies according to series of multiple mapping rules, and the recall ratio was increased by putting central sentences into the set of abstract sentences. The experimental results show that multiple mappings can obtain stable performance in short text summarization, the F measures of ROUGE-1 and ROUGE-2 tests are 0.49 and 0.35 respectively, which are better than the average level of NLP&CC2015 evaluation, proving the effectiveness of the method.

Reading imitating of Brain-Computer Interface (BCI) works on synchronous mode, but in practice users want to switch between "work" state and "idle" state freely, namely asynchrony. Therefore, a closing-eyes fixed time as the switch between the two states was proposed to solve the problem. Firstly, an experimental scheme was put forward, then the features of Electroencephalography (EEG) signal were extracted in time and frequency domains respectively, features of time domain were classified by Support Vector Machine (SVM) and the K-means algorithm, and features of frequency domain were classified by SVM. The highest recognition rates of time domain were 95% and 89.17%, the average time needed for classification were 1.89s and 0.11s respectively. The highest and the average recognition of frequency domain rate were 86.25% and 81.875% respectively. The experimental results show that this scheme can achieve the goal of switching the two states freely.

In order to avoid network congestion, concerning that the current algorithms have not considered the aspects of network flow distribution and user's perception, a routing algorithm which can realize maximum load balance was proposed. The algorithm can decrease the maximal bandwidth utilization rate of network with delay guaranteed. The experiment based on real Abilene2 network topology shows that the proposed algorithm can alleviate the network congestion and improve the network utilization rate over 50% effectively. Compared with the existing algorithms, the proposed algorithm can meet two requirements of the bandwidth utilization and network delay. In addition, by adjusting the parameter values it can meet different business requirements in actual networks.

As for the image denoising filter method, the model proposed by J. Weickert does not consider the distinctions between the smooth area and other image features. The diffusion in smooth area is also in accordance with the eigenvalues of local structure characteristics, thus inevitably producing false edges in smooth area. An improved anisotropic diffusion method was proposed. This method firstly used the Wiener filter to weaken the influence of noise on the image, then coherence was applied to judge image feature correctly, as edge region, smooth area, T-shape corner and so on, and the diffusion tensor's eigenvalues in corresponding region were set based on image feature. The experimental results show that the improved method can not only achieve better results in elimination of noise and protection of edge, but also remove false edge in smooth area effectively and get higher peak signal-to-noise ratio.

Ability of resisting authorization assault is weak for existed group key distributed scheme.A group key distributed algorithm based on role authorization was proposed.The algorithm improves ability of resist and depresses threat of security on authorization assault by importing role authorization restricted in access control for group.Comparing with the other alike schemes,the proposed scheme is secure and useable.

Based on a PDA project, a communication protocol which communicated through PSTN was introduced. Then, a series of representative link layer protocol models using Petri net were described abstractly. By the direction of Petri net emulation tool, these models were modified and improved gradually. Finally, a protocol model which could be applied in the practical work was achieved.