There is not only sensor noise, but also outlier disturbance when a robot explores in unknown environments. The traditional EKF-SLAM algorithm does not consider the impact of outlier disturbance that may lead to positioning failure. The new algorithm detects the outlier disturbance by comparing two observations result using polar coordinates. Covariance would be inflated when disturbance is detected, so that system state of uncertainty is expanded and the state quickly converges to the true value. Simulation results show that the proposed algorithm is better than EKF-SLAM both in mobile robot SLAM accuracy and robustness.
The existing methods ignore multicomponent characteristics of evolution process of Internet public opinions, which leads to an unsatisfactory performance of analysis and modeling. To deal with the problem, this paper presents an evolution analysis and modeling method of Internet public opinions based on Empirical Mode Decomposition(EMD). It decomposes the evolution process of Internet public opinions by EMD, to form trend component, period component, mutation component and random component. Then it analyzes and models the evolution process of Internet public opinions by analyzing and modeling the above-mentioned components. Experiments show that the components decomposed by EMD have clear physical meanings, which can help to analyze the evolution patterns of Internet public opinions; at the same time, the method has good forecasting performance, thus is more suitable.
This paper presents a digital watermarking algorithm based on audio features and the relatively smaller values of the low frequency of DWT coefficients. The proposed algorithm analyzes the zero-cross ratio and the short-time energy of frame to select the appropriate threshold for initial discarding the high-frequency signal components of the audio frame, selecting the audio frame to be processed. The selected audio frames are stitched together and perform discrete wavelet transform, choosing the low-frequency coefficients and segmenting, using the sum binary value of the neighboring three watermark bit combination to determine the location of the watermark embedding, and make its value smaller. The proposed algorithm for blind watermark detection reduces the extraction time complexity of low-frequency components through the analysis of audio features, and improves the robustness of the watermark.
The aircraft sudden failure is a kind of random faults, which is a serious threat for the safe. To present the law of the aircraft sudden failure, this paper proposes to analyze and disclose the mechanism, the feature and procedure of the aircraft sudden failure evolution by dissipative structure theory. Based on that, it models the sudden failure evolution model on aircraft via time varying entropy and time varying frequency band energy distribution, and then it simulates the model by the surge of aero-engine. The results suggest that the entropy and the frequency band energy distribution of the dissipative structure are useful to present the procedure and the feature of the aircraft sudden failure evolution.
A dynamic graph software watermarking algorithm based on the m-n Variable Carrying Rule(VCR) is proposed towards the drawback of the slow recovery rate and the data expansion of software watermarking sharing algorithm. This algorithm takes advantage of the correspondence of watermarking, m-n Variable Carrying Number(VCN), permutation number and Permutation Graph(PG) to implement the watermarking sharing and encoding. When the watermarking is embedded, it uses the VCR to share the watermarking as VCN, and then convertes them into a permutation number with a perfect Hash function, at last encodes them as the PG and embeds it in the program execution code. The watermarking extracting is the reverse process of the watermarking embedding. Experimental analysis shows that this algorithm decreases the program load and the watermarking recovery time complexity and improves the watermarking steganography and error correction capability.
Combined Input and Crosspoint Queued(CICQ) switch fabric can effectively isolate input ports and output ports because of crossspoint buffers. Due to this fabric, it can reduce the complexity of the scheduling algorithm. This paper researches the CICQ switch and a lot of different types of scheduling algorithms for CICQ switch and proposes an algorithm based on flow control, called FCSA. Extensive simulation results using OPNET show that the algorithm achieves a satisfactory delay and throughput performance under both uniform and a broad class of non-uniform traffic patterns. Additional simulation results in the satellite onboard switch also using OPNET show that the proposed algorithm is suitable to apply to implement onboard satellite switch with different bursty traffics, because of its low complexity and capability in hardware implementation.
For the problem of background interference in wound infection detection by electronic nose, this paper proposes a background interference elimination algorithm of Independent Component Analysis(ICA) with reference vector. It employs ICA to decompose signals of the sensor array and extract independent components, and discriminates useful sources and background interference through the correlation between the independent components and a reference vector. Then neural network classifier is used for discrimination. Experimental results show that the algorithm can effectively eliminate the electronic nose background interference and improve the recognition accuracy rate of wound infection.