查看更多>>摘要：Proxy ring signature is a proxy signature designed to protect the privacy of the proxy signer. In this paper, we propose a new proxy ring signature based on the Schnorr's signature. Our scheme combines the idea of the Schnorr's signature with the method of existing structure of proxy ring signature. In order to improve the performance, we eliminate the use of bilinear pairing operation. We only use the hash function in the signature verification phase. Because of above features, the proxy ring signature scheme we proposed is more efficient in computation. We also prove that our scheme is unforgeable against all kinds of adversaries in the random oracle model.
查看更多>>摘要：The local crowd density and the crowd distribution estimation tasks are useful but challenging. There are two main problems which limit the performance of existing algorithms. The first one is that there are not enough labeled training samples to build the high-performance estimation model. Another one is that existing methods lack the supports of physical theories of the crowd. To remedy them, a novel crowd density field model is proposed, which is deduced by jointing crowd dynamics theory and social force model. A crowd counting method based on the proposed crowd density field model is introduced to measure the proposed crowd density field model. Extensive experiments confirm the effectiveness of the proposed plan.
查看更多>>摘要：For an odd prime p and positive integers r, d such that 0 < d ≤ pr , a generic construction of d-ary sequence based on Euler quotients is presented in this paper. Compared with the known construction, in which the support set of the sequence is fixed and d is usually required to be a prime, the support set of the proposed sequence is flexible and d could be any positive integer less then pr in our construction. Furthermore, the linear complexity of the proposed sequence over prime field GF(q) with the assumption of qp?1(≡) 1 mod p2 is determined. An algorithm of computing the linear complexity of the sequence is also given. Our results indicate that, with some constrains on the support set, the new sequences possess large linear complexities.
查看更多>>摘要：Network analysis based on graph theory has greatly promoted the cognition of the human brain network. A detailed brain network function connection analysis was carried out for the brain of normal human brain and mental illness patients. We studied the Magnetoencephalography (MEG) of 9 normal subjects and 9 schizophrenics in left hemisphere temporal lobe and frontal lobe regions. And obtained the dynamic function connectivity matrix by calculating Pearson correlation coefficients that based on sliding time window and short-time Fourier transform, and constructed weight and binary network by graph theory. Analyzed the small world properties of normal human brain networks, and compared the differences of network between normal subjects and patients with schizophrenia.
查看更多>>摘要：Reverberation is the major interference of active detection, discrimination between target echo and reverberation is difficult when the reverberation is very strong. For the distinguishing of underwater target echo with strong interference, the modulation feature of echo and reverberation spectrum are characterized by signal spectral flatness measure, and the relationship between signal spectral flatness and target physical properties are theoretically formed. A method of discrimination between broadband underwater target echo and reverberation that based on signal spectral flatness characteristics difference is proposed and studied. Sea experiment results of complex underwater target broadband acoustic scattering have shown that signal spectral flatness characteristics of underwater target broadband echo and reverberation have obvious differences. Target echo and reverberation can be well distinguished using the proposed method.
查看更多>>摘要：To deeply understand the essential relationship between two different-frequency signals and explore the phase synchronization law in frequency standard comparison, a novel modeling building method of Lissajous figure reversal period is proposed based on the group quantization phase processing. The relationships between the Lissajous figure reversal period and group period are revealed. The frequency deviation and nominal frequency of the measured signal are obtained using the group period and number of inflection point in the Lissajous figure. The results of a frequency standard comparison can accurately achieved using the frequency deviation. A lot of noise problems introduced by the frequency divider, frequency multiplier and frequency mixer are solved in the traditional frequency standard comparison, and the high-precision frequency standard comparison results can be quickly obtained using the proposed method. The experimental results show that a close relationship exists among the Lissajous figure reversal period, group period and frequency deviation. The measured frequency can be precisely calculated using the relationship, and the frequency stability of system can reach the E-112/s level.
查看更多>>摘要：Sand painting is a form of combination of arts and modern aesthetic, which relies on profound cultural heritage and cultural connotation. To provide the public and artists with an opportunity to better understand sand painting and make art creations surpris-ingly, this paper proposes a self-adaptive algorithm to simulate sand painting in a real-time way. Our simulation system exploits the height field to simulate sand flow to achieve a fast even real-time target. Seven frequently-used styles of painting techniques are elaborately defined and successfully simulated in our system, including pouring, seeping, dotting, stroking, sweeping, multi-stroking, and pinching. The procedure of sand flow is mainly consist of two key parts: sand accumulation and collapse. The direction field is introduced into the system to control a similar appearance of a normal distribution, which will be of benefit to sand accumulation algorithm. A self-adaptive approach is taken advantage of into sand collapse algorithm to present certain appearances with various details. A color factor is also considered for realistic simulation in this paper in two ways: one is the background color of sand table/canvas and the other is the natural color of sand particles themselves. User feedbacks and experimental results reveal that the algorithm of sand painting simulation in this paper can realize kinds of sand painting arts of creations easily, realistically, effectively and interactively.
查看更多>>摘要：The present study proposes an improved Quantum-behaved particle swarm optimization algorithm based on the two-body problem model (QTPSO) for solving the problem that other quantum-behaved par-ticle swarm optimization algorithms easily converge on local optimal solutions when solving complex nonlinear problems. In the proposed QTPSO algorithm, particles are categorised as core particles and edge particles. Once the position of the core particle is determined, the edge particle appears in the vicinity of the attractor exhibiting a high probability, and the attractor is obtained through the random weighted sum of the core particle and the optimal mean position. Through simulation of the motion of these two particles by applying the interaction of the particles in the two-body problem, this mechanism not only improves the diversity of the population, but also enhances the local search capacity. To validate the proposed algorithm, three groups of experimental results were obtained to compare the proposed algorithm with other swarm intelligence algorithms. The experimental results indicate the superiority of the QTPSO algorithm.
查看更多>>摘要：Millions of smart meters have been installed all around the world so far. The reported meter readings are conducive for utility companies to provide high quality of service. To efficiently and securely make use of those readings, data aggregation has been widely studied. Lu et al. proposed an Efficient and privacy-preserving aggregation (EPPA) scheme for secure smart grid communications in recent years. Unfortunately, we found a man-in-the-middle attack to the EPPA scheme in this paper. We then propose a new meter reading aggregation scheme, namely Universally composable meter reading aggregation (UCMRA) scheme, in order to resist against that attack. Moreover, we give a universally composable symbolic analysis to prove the security for UCMRA scheme. This proof also enables the UCMRA scheme to adopt an alternative cryptographic primitive arbitrarily, as long as the primitive meets the requirements of the corresponding ideal functionality. Finally, the experiment results show that the performance of the UCMRA scheme is almost as good as that of the EPPA scheme.
查看更多>>摘要：An important aspect of a Speech tutoring aimed talking-head system (STTS) is the accuracy of produced articulatory movements. Little work has been done for the Articulatory movements' accuracy (AMA) evaluation in STTSs. Although subjective evaluation is reliable, it is time consuming and inconvenient. The traditional objective evaluation is comparing the motion of several points on the surface of the synthetic articulator to the Electromagnetic articulography (EMA) data which describes the motion of corresponding points on the articulatory surface of a speaker. The EMA information is too limited to describe the whole shape changing of deformable articulators for a speech process. To solve this problem, we propose a substantially different objective evaluation method based on a separately recorded medical video. The synthetic articulatory shapes in a speech process are compared to the corresponding shapes tracked from the medical video. This method is translation, rotation, and scaling invariant which allows the comparison of the shapes from the synthetic tongue and the medical images. The time difference problem of synthesis results and medical video is solved by introducing Dynamic time warping (DTW) to the proposed method. Experimental results demonstrate that our method has the ability to evaluate the deformation shape accuracy from an entire articulation process. The comparison results suggest that our method is more accurate than the traditional method especially for deformable articulators.
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