Xiaofeng Gong

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Direction-of-arrival (DOA) estimation based on the array of three-component electromagnetic vector-sensors is considered within a biquaternion framework. A relationship is established between the biquaternion covariance and the combination of both complex covariance and cross-product. By exploiting this relationship, the DOA estimates can finally be(More)
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The dynamical origin of complex networks, i.e., the underlying principles governing network evolution, is a crucial issue in network study. In this paper, by carrying out analysis to the temporal data of Flickr and Epinions-two typical social media networks, we found that the dynamical pattern in neighborhood, especially the formation of triadic links,(More)
Existing software systems designed to support learning do not adequately provide for vicarious learning in a cross-institutional collaborative environment. We have developed an architecture based on role-based access control, which provides the necessary security, robustness, flexibility, and explicit formulation of policy. Such an architecture is general(More)
—Direction-of-arrival (DOA) estimation for multiple sources using the array of three-component electromagnetic (EM) vector-sensors is considered in this paper within a tensorial framework. The cross covariance tensor is firstly defined as the one in which the cross covariance terms between every two components of the array signals are arranged in a(More)
In this paper, we numerically investigate the development of generalized synchronization (GS) on typical complex networks, such as scale-free networks, small-world networks, random networks, and modular networks. By adopting the auxiliary-system approach to networks, we observe that GS generally takes place in oscillator networks with both heterogeneous and(More)
The last decade has seen the explosive uptake of technologies to support true Internet-scale distributed systems, many of which will require security. The policy dictating authorisation and privilege restriction should be decoupled from the services being protected: (1) policy can be given its own independent language syntax and semantics, hopefully in an(More)