To solve anycast routing problem with multiple QoS constraints, a improved hybrid algorithm which combines genetic algorithm and ant colony algorithm is proposed. In the initial period of hybrid algorithm, genetic algorithm was used to distribute pheromones in links and code and optimize control parameters of ant colony algorithm. Through judgment function, this algorithm can judge the time to combine the genetic algorithm with ant colony algorithm, and initialize the pheromones and start the ant colony algorithm at the last period of hybrid algorithm. To avoid hybrid algorithm falling into local optimal solution, a mutation operator was introduced in algorithm hybrid to update local pheromones of new path produced by mutation operation and reduced pheromones concentration on optimal path in time. The NS2 simulation results show that this algorithm can commendably solve the anycast routing problem with multiple QoS constraints, and its performance is better than other two algorithms.

Wireless sensor networks (WSN) are used extensively in various important areas of agriculture. Many of the associated activities involve the transmission of data or control commands through gateways that connect the servers to 3G networks. In this paper, we investigate the issues caused by Radio Resource Control (RRC) state transitions, which introduce high sudden delays in TCP packets. The packets that are subjected to these delays are then usually retransmitted because of timeouts. Further, the recently recommended TCP retransmission timer settings (RFC6298) reduce the initial retransmission timeout (RTO) from the previous three seconds to one second, further exacerbating the phenomenon of SYN packet retransmission, because a SYN packet is always the first packet to trigger the RRC state to change. We conduct a number of tests to examine the phenomenon and analyze the effect of this spurious retransmission timeout. Consequently, we propose recommendations for improvement.

This thesis aims to discuss the problems now existing in mining probabilistic of MapReduce Apriori, and to put forward an algorithm about mining probabilistic frequent itemsets based on cloud computing. This algorithm proposes to reduce the quantity of candidate item sets by the strategy of designing to decrease candidate item sets, and divide data sets and candidate item sets into related nodes in order to minimize candidate item sets. By compressing the transaction set to accomplish connecting optimization, it can avoid producing massive alternatives item sets in the process of self-link to improve the operation efficiency of algorithm.

Wireless Mesh Networks are new type of multi-hop wireless network with high rate and strong reliability. Multipath routing is employed for load balancing, fault tolerance purposes in wireless mesh networks. With the more and more application need, multipath routing has gradually become an important topic to study. An algorithm of multipath routing algorithm based on dynamic source routing protocol(DSR) is proposed in this paper. This algorithm provides multiple QoS guarantee, such as bandwidth, delay and cost, achieves multipath load balancing and improves networks’ performance. The experimental results show that our algorithm achieves better QoS performance and more advantages over DSR and split multipath routing protocol(SMR).

This paper put forward an image fusion algorithm which based on the analysis of the imaging theory fusion, the fusion process is first will have been registration of the original image into several pieces, we calculate the correlation of corresponding piece, as the image contrast evaluation criteria, by selecting two images in the clear image block form fusion image. This paper discusses the principle analysis from optical imaging, the cause of the fusion algorithm, to avoid the use of Gaussian Blur model to explain the image of a fuzzy controversy. The experimental results show that the proposed algorithm is good real-time performance, for registration fusion image can achieve even more than general wavelet decomposition of the fusion algorithm.