查看更多>>摘要：The complexity measures of chaotic or periodic signals are perpetual topics of interest to data scientists. This work adheres to the framework of the traditional 0-1 test for chaos and replaces sine and cosine functions by modified sign functions. The compressive mapping rules chosen are one-threshold of three-value or three-threshold of five-value. In new criteria for chaos in forms of the 3s plot and Ks metric compared with 0-1 test results, the periodic state of data features a short beeline instead of a big ring in the pq plot and signs the nearest zero mark, while the chaotic state signs a simple curve instead of a random-walking shape in the pq plot, and shows the nearest one mark. By computing the Lorenz equation evolution under the contrast tests of the Poincare section and Lyapunov index, we visualize a new chaos-criteria design in symbolic dynamics and data compression principles, and our work may lay the foundation for further expressing the chaotic appearance of novel signals deep into future brainets.
查看更多>>摘要：Electromagnetic compromising emanations are potential threat to computer security. Computer emits energy in the form of electromagnetic wave which includes the processed information. The electromagnetic wave can be received and decoded in the distance, so the unintended information leakage occurs. In this paper, the automatic information reconstruction for computer electromagnetic eavesdropping is studied. This paper attempts to combine simple digital signal processing method for the first time to extract electromagnetic leakage information. The performance of the new method is presented numerically and experimentally. Compared with other algorithms, this method has strong practicability and reliability. Under complex electromagnetic environment, the synchronization parameters can be extracted and the information can be reconstructed automatically, quickly and reliably.
查看更多>>摘要：Existing dynamic data possession veri-fication schemes not only suffer from low efficiency of rebalancing its Merkle Hash tree (MHT) when executing data updating, but also lack effective mechanism to verify multi-version files. Aiming at these problems, this paper propose a new data structure called Rank-based multi-version Merkle AVL tree (RBMV-MAT) to achieve efficient batch updating verification for multi-version data. RBMV-MAT uses a special lock and relaxed balance to decrease the frequency of rebalacing operations. The experimental results show that our efficient scheme has better efficiency than those of existing methods.
查看更多>>摘要：An Index geographic gossip (IGG) algorithm is proposed. Relay nodes participate in infor-mation exchange and updating. The cumulative number of times these nodes participate is characterized by an index number, which can be used to accelerate information updating. The convergence property of the IGG algorithm is theoretically analyzed in ring and grid network topologies. The IGG algorithm improves the standard gossip algorithm by a gain of O(n) in both convergence time and communication cost. Compared to the geographic gossip algorithm, the IGG algorithm has a gain on the order of O(n) and O(n1/2) in the average hop count for information exchange and communication cost, respectively. Finally, the proposed IGG algorithm is compared with various baselines through simulations, and it is shown that significant performance gain can be achieved.
查看更多>>摘要：A new frequency standard comparison system is proposed based on the group quantization phase processing. By shortening the width of phase coincidence fuzzy area and capturing the best group phase coincidences, we reduce the randomness of the counting gate and improve the measurement precision of the comparison system. The method is based on the Field-programmable gate array (FPGA), which not only retains the advantage using phase synchronization detection technology to overcome the ±1-word counting error, but also accelerates the system response time, simplifies the measurement equipment, and reduces the development cost and power consumption. The experimental results show that the method is reasonable and scientific, and the comparison accuracy of the system can reach the E-12 s-1 level, obviously superior to the measurement accuracy of the traditional frequency standard comparison method, which has a wide application and popularization value.
查看更多>>摘要：Sensor networks contain a large number of nodes that can perceive changes of external environment, which makes sensor networks particularly suitable for target tracking and discovery. In practical applications, once the sensor nodes are arranged, it is difficult to move them. We focus on analysing the target discovery ability of static-sensor networks. We divided the target into two kinds, one is persistent target and the other is instantaneous target. We investigate target discovery probability and discovery delay with different nodes density, sensing range and duty cycle. Energy saving is still the most important problem for the applications of sensor networks. Balancing target discovery capability and lifetime of the whole sensor network is necessary. Based on the theoretical analysis, we propose a coverage adaptive optimization algorithm that significantly prolongs the life of sensor networks. Simulation results show the advantage of coverage adaptive optimization algorithm over previous proposed methods.
查看更多>>摘要：Distributed Denial of Service (DDoS) attack is a difficult issue which needs to be addressed in Software defined networking (SDN). In order to help the controller to weather out the DDoS attack, an efficient controller scheduling method is proposed. The proposed controller scheduling method uses the normalized waiting time, length and extent of the switch being attacked to choose the request that needs to be processed by the controller. The evaluation results validate that compared with the polling based controller scheduling method, the proposed one can significantly reduce the connection failure ratio and delay.
查看更多>>摘要：At present, fixing Android system vulnerabilities relies on official Android support and various equipment manufacturers, and it is mainly implemented by system upgrades. This situation causes many problems, such as high costs and delayed fixing of vulnerabilities. This study is performed to design a novel fixing policy construction model targeting Android system vulnerabilities, which can be used for vulnerability feature quantification and fixing policy customization. On this basis, a novel security vulnerability solution called DroidHFix is proposed and implemented. This solution constructs security policies and loads security policy files during the risky application startup. The system helps to fix Android system vulnerabilities dynamically and defend against attacks on the risky application depending on sys-tem vulnerability exploitation. Experimental results show that DroidHFix fixes the Android system vulnerabilities effectively, with good performance and compatibility.
查看更多>>摘要：Network coding technology is always employed to improve the throughput of Wireless mesh networks (WMNs). However, traditional routing protocols based on network coding can only passively wait for coding opportunity, and the routing process is oblivious to coding operation. Taking into account the high throughput requirement in WMNs, a novel Coding awareness routing protocol with maximum benefit (CARMB) is proposed in this paper. The CARMB could actively create potential coding opportunities in the process of path establishment, which attempts to choose an appreciated route with more coding benefits among available path candidates. Simulations through NS-2 demonstrate that the CARMB performs better than traditional schemes in enhancing average end-to-end throughput and increasing coding opportunities as well as reducing average end-to-end delay. In particular, average end-to-end throughput and coding gain could be improved by 11％ and 17％ respectively compared with previous approaches.
查看更多>>摘要：Convolutional neural network (CNN) has become a promising method for Synthetic aperture radar (SAR) target recognition. Existing CNN models aim at seeking the best separation between classes, but rarely care about the separability of them. We performs a separability measure by analyzing the property of linear separability, and proposes an objective function for CNN to extract linearly separable features. The experimental results indicate the output features are linearly separable, and the classification results are comparable with the other state of the art techniques.
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维普