ProSync： A protective synchronization scheme for NC-OFDM based opportunistic spectrum sharing system

A protective synchronization scheme （ProSync） for the non-contiguous orthogonal frequency-division multiplexing （NC-OFDM） system is proposed in this paper, aiming to minimize the impact of cross-band interference in opportunistic dynamic spectrum sharing networks. ProSync partly shrinks the preamble at the transmitter and exploits two multi-band filters at the receiver. By doing so, the potential interference suffered by NC-OFDM users, including both the cross-band interference and self interference, can be greatly reduced. Simulation results verify the effectiveness of ProSync, which is able to lower the carrier frequency offset （CFO） estimation error by up to 50%, compared with the traditional method.

浅析面向用户关系的网络隐私攻击与保护

随着网络信息技术的发展和社交网站的普及,网络用户隐私泄露问题变得日益严重。本文介绍了三种类型的网络隐私攻击手段,并重点讨论了面向用户关系的网络隐私攻击与保护。本文采用图的理想模型描述网络用户关系,分析了随机化社交网络图中边的保护技术。通过对图频谱属性的研究,整体评估了不同随机方法的保护效果。用现有实验验证了频谱保护技术相比于基本方法对保护用户关系的优越性。