Zhenwei Zhang

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In this paper, we propose a new multiple-level power allocation strategy for the secondary user (SU) in cognitive radio (CR) networks. Different from the conventional strategies, where SU either stays silent or transmit with a constant/binary power depending on the busy/idle status of the primary user (PU), the proposed strategy allows SU to choose(More)
With the development of the techniques of Event Detection and Tracking, it is feasible to gather text information from many sources and structure it into events which are constructed online automatically and updated temporally. There are always diversified versions to describe an event and users usually are eager to know all the versions. With the huge(More)
A nonlinear-feedforward-feedback controller is designed for an electric clutch actuator, which adopts ball screw as the speed reduction mechanism. Ball screw has high transmission efficiency. However, it does not self-lock. Moreover, the nonlinear friction force, load force, and the nonlinear characteristics of the motor drive circuit increase the(More)
With the rapid development of Internet technology and the explosive growth of data, the storage system designed by tightly coupled hardware and software is limiting the development of storage technology severely, and unable to meet the fast changing needs in the mobile Internet and exploding big data era. Software Defined Storage (SDS) as a new storage(More)
Human gait is a complex interaction of many nonlinear systems and stride intervals exhibiting self-similarity over long time scales that can be modeled as a fractal process. The scaling exponent represents the fractal degree and can be interpreted as a "biomarker" of relative diseases. The previous study showed that the average wavelet method provides the(More)