If all nodes of a sensor network worked simultaneously, not only there would be a lot of redundant information, but also they would have great adverse impact on network throughput, bandwidth, latency, energy and network lifetime. Consequently, density control technology is necessary for sensor networks, because it can reduce the number of active sensor nodes under the precondition of ensuring network coverage and network connectivity. This paper proposes SNDC (Sensor Network Density Control), a location-free and range-free density control algorithm for wireless sensor network to keep as few as possible sensors in active state to achieve an optimal complete connected coverage of a specific monitored area by periodically sending three beacons of different transmission ranges. Inactive sensors can turn off sensing modules to save energy and sleep. Simulation results show that this algorithm can prolong the network lifetime and guarantee the small number of active nodes and complete network coverage.

Beam cooperative scheduling of downlink transmission is an important technique to improve the spectrum efficiency in next generation mobile networks. This paper focuses on switched beams (the emission angles of the beams are fixed) and proposes a joint beam-power coordinative scheduling algorithm among neighbor sectors in the downlink of mobile systems. Each sector coordinates the applied order and transmitted power of the beams with adjacent interfering sector, so as to reduce inter-sector interference and maximize throughputs. This scheduling problem is modeled as a constrained optimization problem and solved by our proposed iterative approach. Computer simulation shows that the proposed approach significantly outperform the existing round robin beam servicing approach and the approach that applies only beam cooperative scheduling.

It is very important for wireless sensor network to position the nodes’ location because location information is favorable for providing network service such as geographic routing, people tracking and so on. After researching the range-based atomic multilateration algorithm carefully, this paper presents a novel positioning algorithm based on adaptive genetic algorithm (AGA). The new positioning algorithm uses adaptive genetic algorithm to search the optimal solution of nonlinear multivariate positioning equations set. Furthermore, the proposed algorithm uses a new model to estimate range error in order to improve the localization accuracy. Simulation results show that the proposed scheme has better robust performance. Compare with general genetic algorithm, adaptive genetic algorithm has better localization accuracy and higher speed of convergence.

In this paper, the AOS effective throughput rate is analyzed firstly. Then, in order to improve the effective throughput rate, a scheme of AOS cross layer transmission system is presented. In the proposed scheme, based on the space channel state, the dynamic optimization parameters of AOS Space Date Link Protocol sublayer and AOS Sync and Channel Coding sublayer are selected. Then the switch thresholds are presented. Finally, the effective throughput rate of the proposed AOS cross layer transmission system is simulated. Simulations show that the throughput rate can be optimized effectively.

The ultimate goal of researches on Wireless Sensor Networks (WSNs) is how to improve network energy efficiency as possible as can. Certainly, there are many researches concerned to energy efficient scheme in wireless sensor networks. Dividing geographically distributed sensor nodes into different clusters in order to decrease transmission range and transmission quantity is one of traditional energy efficient strategies for WSNs. In this paper, an energy efficient ACE clustering algorithm named EEACE in short is presented to improve the performance of ACE scheme. The EEACE algorithm is derived from ACE scheme but overcomes many shortcomings of ACE and other clustering algorithms such as famous LEACH and DCHS. By dividing sensor nodes into uniform clusters with minimum communication cost, EEACE algorithm improves the network’s performance at aspect of lifetime and energy efficiency significantly. The simulation results verified that EEACE algorithm prolongs the lifetime of WSNs by more than 15% comparing with ACE and DCHS algorithm.

For phishing problems and its essential characteristics, the authentication protocol of anti-phishing based on two-direction, two-factor, and interaction is proposed, and its safeties are investigated. For PKI security infrastructure and B/S technology model under Internet, an interactive authentication mechanism based on special custom image and client program is designed and implemented. The method is universal to authenticate any server on Internet. It is a new solution of anti-phishing.

The core of smart antenna is its adaptive algorithm. For the characteristics of TD-SCDMA mobile terminal, we analyze the advantages and disadvantages of various algorithms and propose a semi-blind algorithm combining the NLMS algorithm and the CMA algorithm in this paper. The new semi-blind algorithm has strong robustness and low complexity. It is suitable for smart antenna of TD-SCDMA mobile terminals.

The peculiarity of Wireless Sensor Networks demands extra consideration during the design of the security protocol. One of the most challenging yet important security features in Wireless Sensor Network is in establishing trusted communication between sensor node and base station. While the term trusted has been widely used referring to valid nodes in the group, this paper discuss the term trusted based on the specifications of Trusted Computing Group (TCG) and presents an IBE-Trust security protocol utilizing well-known identity based encryption scheme. The protocol incorporates ideas from Trusted Computing Group and Identity-based cryptosystem by Boneh Franklin in ensuring trusted and secured communications between sender and receiver. The proposed protocols were then modeled using the high-level formal language HLPSL and verified using the model checking tool AVISPA. Analysis on the proposed protocols is presented at the end of this paper.

According to the instant high rate and high intensity of LDoS attacks, this paper explores using fair queue management mechanism to mitigate their effect. We perform simulation experiments to evaluate the performance of fair AQM FRED and CHOKe under LDoS attacks. The simulation results show that they are able to reduce the impact of the attacks in various degrees. FRED outperforms CHOKe in throttling the attacks, but it is slightly inferior to CHOKe in time performance.

There are some classic structured multi-signature programs, such as Burmester’s, Harn’s and Lin’s schemes that can not resist inside attack and outside attack. In this paper, we briefly review Burmester’s program and relate safety analysis, Burmester’s scheme vulnerable to forgery attack. Then we propose a structured multi-signature scheme against forgery attack. In the new scheme, we increase the signature parameter verification to improve security.