To estimate pseudo code period of multipath tamed spread spectrum signal, a blind method based on power spectrum reprocessing was proposed to estimate the pseudo code period of the tamed spread spectrum signal in multipath channel. Firstly, the general single path tamed spectrum signal was extended to multipath model. Then, the primary power spectrum of the signal was calculated on the basis of the tamed spread spectrum signal model in multipath environment. Next, the obtained primary power spectrum was used as the input signal to calculate the secondary power spectrum of the signal, and the theoretical analyses showed that the peak line of the secondary power spectrum of the signal would appear in the integral multiple of the pseudo code period. Finally, the pseudo code period of the tamed spread spectrum signal could be estimated by detecting the spacing between the peak spectrum lines. In the comparison experiments with time domain correlation method, the Signal-to-Noise Ratio (SNR) of the proposed method was improved by about 1 dB and 2 dB when the correct rate of pseudo code period was 100% and the length of pseudo code sequence was 127 bits and 255 bits, and the average accumulation times of the proposed method was less under the same condition. The experimental results show that the proposed method not only has less computational complexity, but also improves the estimation correct rate.

Intention is the main method of crowdsourcing service in Crowd Sensing (CS), in view of the existing methods in the process of service without fully considering the effects on CS which are from the number of participants and malicious competition, a kind of Incentive Mechanism based on Reverse Vickrey Auction model (RVA-IM) method was proposed. Firstly, incentive mechanisms of crowdsourcing were studied in this paper, in combination with reverse auction and Vickrey auction, a reverse auction model oriented to task covering was built. Secondly, the in-depth analysis and research on the key technical problems involved in the model were conducted, such as task covering, reverse auction selection and reward implementation. Finally, the effectiveness of RVA-IM method was analyzed in five ways:computational efficiency, individual rationality, budget-balance, truthfulness and honesty. The simulation results show that, compared with IMC-SS (Incentive Mechanism for Crowdsourcing in the Single-requester Single-bid (SS)-model) and MSensing (Myerson Sensing) method, RVA-IM method is more effective and feasible. It can solve the problem of malicious competition in the existing methods, and improves the average rate of service completion by 21%.

During the procedure of the stone image segmentation, there are some practical problems such as the great difference of stones and different regions of a piece of stone having distinctly different brightness characteristics. A growing method based on degree fussy number was introduced. During the region growing, different growing functions were selected. The conception of relative statistical character was put forward. Using this conception, not only can the seeds used for region growing be selected, but also can the size of stone and the main relative statistical character of the whole stone be known. All these above were the base of the region growing method based on different-size degree fussy number. Using this method, stone image segmentation can get a great result.