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Key management is very important for Wireless Sensor Networks' (WSNs) security. Many key management protocols have been proposed recently. However, most of them assume that the area which nodes monitored is equal security, and the probability of nodes being compromised to be the same for every node. In some application environments(e.g. in battle field), the probability of nodes being compromised in an enemy controlled area is larger than in our controlled area. In this paper, a key management method for such application environment which the security is non-uniform is proposed. The optimization for the tradeoff between storage and calculation overhead for Blom Matrix is taken into account; the secret symmetric matrix is generated by conjugate chaotic sequence, it is easy to implemented in physical circuit and more secure.

This paper is to deal with the blind extraction problem of chaotic signals by using a linear mixing model. In this model, a novel method to describe the distance function in a high dimensional space is proposed which relates the kernel function to objective function. When adopting the artificial bee colony algorithm (ABCA) as an alternative method to solve a multi-modal optimization problem, its analysis under a Markov chain model is also presented. The simulation results show that the objective function of this article has low complexity, and the artificial bee colony algorithm converges to a local minimum quickly. To be specific, the target function is constructed by combining the advantages of the proliferation exponent and the distance kernel function. The proliferation exponent can reflect the chaotic properties of a signal to a large extent, and the distance kernel can help to describe the statistical properties in a higher dimension. Due to the fact that only one frame of time-delay embedded signal is adopted, the computational complexity of our target function is low. The artificial bee colony algorithm is shown to be advantageous over other swarm algorithms. Although adopting ABCA for our evaluation function seems easy, we analyze why this algorithm can work, in contrast to the fact that most literature only runs some simulations to confirm its usefulness. Our analysis is only for a special case when the number of employed bees is set to be 2 and the process of onlooker bees and scouts are temporarily omitted. With smaller complexity than the methods based on proliferation exponents and kurtosises, simulations show that our method can have excellent performance when evaluated by correlation coefficients.

The effect of Vlf communication is impacted by the environment factors, so the effect lacks the uniformity in the region of time, space and frequency. It made use of the prediction of the vlf wave propagation, applied the waveguide mode theory to set up the math model and process the computer simulation, predicted the signal field strength of vlf, the prediction results accord with the measuring data. Then it implemented to display the spatial distribution of vlf signal field strength combined with the MapX, so as to we could display the cover range of the transmitter's reliable communication. So we can implement the accurate prediction of the communication effect, and the efficiency of submarine communication could be enhanced.

We introduce the development status of human resources in rural Xinjiang of China, analyze its obstacles and difficulties, and finally put forward related countermeasures for the rural human resources development in minority areas.

Differential marketing is a strategy opposed to competitive convergence mainly characterized by seeking development in differences. Therefore, marketing of agricultural products dominated by rural cooperative economic organizations has an important practical role. Taking Manas County in Xinjiang Province as an example, agricultural marketing system dominated by rural cooperative economic organizations develops rapidly, mainly reflected in ① constructing agriculture industry association based on characteristic industry and superior industry ② establishing professional economic association, ③ setting up professional technique research association based on scientific research institutes and institutions of higher educations, ④ forming professional cooperatives based on grass-roots supply and marketing departments. However, there are still some problems, and differential marketing of agricultural products can improve the cohesion of rural cooperative economic organizations. Four aspects should be paid attention to during the concrete strategy application of differential marketing of agricultural products, which are precisely making target market positioning, promoting pollution-free agricultural products, perfecting benefit affiliating mechanism, and improving information service level.

Nonlinear time series denoising is the premise for extracting useful information from an observable, for the applications in analyzing natural chaotic signals or achieving chaotic signal synchronizations. A good chaotic signal denoising algorithm processes not only a high signal-to-noise ratio (SNR), but also a good unpredictability of a signal. Starting from the compressed sensing perspective, in this work we provide a novel filtering algorithm for chaotic flows. The first step is to estimate the strength of the noise variance, which is not explicitly provided by any blind algorithm. Then the second step is to construct a deterministic projection matrix, whose columns are polynomials of different orders, which are sampled from the Maclaurin series. Since the noise variance is provided from the first step, then a sparsity level with regard to this signal can be fully constructed, and this sparsity value in conjunction with the orthogonal matching pursuit algorithm is used to recover the original signal. Our method can be regarded as an extension to the local curve fitting algorithm, where the extension lies in allowing the algorithm to choose a wider range of polynomial orders, not just those of low orders. In the analysis of our algorithm, the correlation coefficient of the proposed projection matrix is given, and the reason for shrinking the sparsity when the noise variance increases is also presented, which emphasizes that there is a larger probability of error column selection with larger noise variance. In the simulation, we compare the denoising performance of our algorithm with those of the wavelet shrinking algorithm and the local curve fitting algorithm. In terms of SNR improvement for the Lorenz signal, the proposed algorithm outperforms the local curve fitting method in an input SNR range from 0 dB to 20 dB. And this superiority also exists if the input SNR is larger than 9 dB when compared with the wavelet methods. A similar performance also exists concerning the Rössler chaotic system. The last simulation shows that the chaotic properties of the originals are largely recovered by using our algorithm, where the quantity for "chaotic degree" is described by using the proliferation exponent.

This paper explored a way to design mechanical structure and motion pattern of a quadrupedal robot to realize pitching motion by mimicking a cat. Four joints configuration styles were obtained by simplifying quadrupedal mammal's body. Referring to the leg motion of a cat, joint motion trajectories were designed and a motion mapping relationship between knee and hip was formulated for the quadrupedal robot. Proved by the experiments with a physical robot, these designs are effective and the quadrupedal robot can walk quickly and smoothly just as a cat does. Otherwise, we find robotic mechanical structure in terms of joint-configuration style, layout of COG, etc. has influences on the performance of the robot. That results in slippage or not-clearance-from-the-ground of feet in motion.