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Zhibing Xu

Publications and source records attributed to Zhibing Xu.

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Antenna Optimization for Decode-and-Forward Relay in Magnetic Induction Communications

Magnetic Induction (MI) communication is effective in underground tunnels for emergency rescue vehicle due to the small-size antenna. It can highly benefit from a cooperative decode-and-forward (DF) relay to achieve a higher data rate. However, its channel gain is extremely position-and-orientation-selective. The unreachable space increases the complexity of the antenna deployment. To find the best antenna position and orientation (PO) of the relay achieving the higher data rate, this paper formulates the optimization problem of the relay MI antenna PO with tunnel constraints. To solve the problem more quickly, we propose to use geometric modeling to eliminate the tunnel constraints and develop a random-search algorithm achieving a fast convergence and excellent global search ability. Simulations show that the proposed algorithm can quickly converge to one optimum which signifies a noticeable improvement of data rate for vehicle MI systems with weak signals.

eess.SP

Reliability Analysis of Polymeric Materials

Polymeric materials are widely used in many applications and are especially useful when combined with other polymers to make polymer composites. The appealing features of these materials come from their having comparable levels of strength and endurance to what one would find in metal alloys while being more lightweight and economical. However, these materials are still susceptible to degradation over time and so it is of great importance to manufacturers to assess their product's lifetime. Because these materials are meant to last over a span of several years or even decades, accelerated testing is often the method of choice in assessing product lifetimes in a more feasible time frame. In this article, a brief introduction is given to the methods of accelerated testing and analysis used with polymer materials. Special attention is given to degradation testing and modeling due to the growing popularity of these techniques along with a brief discussion of fatigue testing. References are provided for further reading in each of these areas.

stat.AP