There are difficulties to guarantee QoS of mobile Ad Hoc networks due to their features of dynamically changing topology and wireless communication. Current QoS techniques for mobile Ad Hoc networks are divided into five categories: link layer solutions, network layer solutions, transport layer solutions, cross layers solutions and cross networks solutions. The main link layer solutions are QoS MAC protocols. The main idea in network layer solutions is QoS routing. Wireless TCP is the main scheme to guarantee QoS in transport layer. To choose route and balance load, cross layer solutions were researched to provide network architectures to support QoS. The main idea in cross network solutions is to propose QoS solutions between mobile Ad Hoc networks and fixed networks. These QoS solutions were introduced and analyzed.

In this paper, a new coding scheme was proposed, which was based on the sequence of its complete binary tree. The scheme is easy to realize and only one positive integer is needed to express the position of the node in XML tree. The time-bounding of identifying the ancestor-descendant relationships is only O(log n). It also supports XML document update. In the scheme, the length of the code is short.

Structural join operation is the main solution to Native XML database query. Based on the survey of existing structural join algorithms, a new structural join algorithm, depth partition based structural join algorithm (DRIAM) was proposed. In DRIAM, input data sets AList and DList were not necessary to be ordered or indexed so that the additional cost was avoided. AList and DList were not necessary to be loaded in the memory. Besides, the timecomplexity of DRIAM was very low.