SUMMARYAd hoc network is a collection of wireless mobile nodes dynamically forming a local area network without the use of any existing network infrastructure or centralized administration. One problem in the design of such network is its wireless vulnerabilities and limited physical security. This paper considers the security attributes and goals of ad hoc network, reviews the latest developments of current routing and security mechanissm including encryption, protocols, user authentication, and physical security. It also explores the new approaches trying to solve current problems and points out the future research directions. These methods will be helpful in the military and other security-sensitive fields.

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The discrete space representation of most scientific datasets (pixels, voxels, etc.), generated through instruments, while being simple, is also verbose and structureless. in order to convert it to a universal 3 0 file fwmat, such as M L , this paper introduces a new type of 3 0 graphic file format generated by a 3 0 imaging camera. It is called GTi format. It then presents a method to manage the disordered data into a well-organized structure, and the conversion procedures between it and other universal j l e formats, i.e., VRML and STL. The test result shows that GTIfile size is much smaller than the other two graphic files os W L and STL and the image can betransfirred with less distortion. The use of GTI format will greatb sirnplifL the rendering, transmission and storage process of graphics files.