查看更多>>摘要：Having the advantages of certificateless signature and the aggregate signature at the same time, certificateless aggregate signature has been widely applied in e-business, e-government and software security since it was proposed in 2007. Although a number of certificateless aggregate signature schemes have been proposed, all of them are based on the classic number theory problem, which are no longer secure in the quantum era. In this paper, a certificateless sequential aggregate signature over number theory research unit lattice is proposed, which is proven to be secure in random oracle model. Moreover, we extend the new scheme into an efficient certificate-based sequential aggregate signature which is also secure in quantum era.
查看更多>>摘要：We study the periods of sequences produced by the cascade connection of two Feedback shift registers (FSRs). The period of the cascade connection is the period of the longest sequences it produces. An upper bound for the period of the cascade connection of a Nonlinear feedback shift register (NFSR) into a Linear feedback shift register (LFSR) is established. In addition, the cascade connection of an n-stage maximum-length LFSR into an n-stage NFSR is called an (n + n)-stage Grain-like NFSR, and we propose two families of (n+n)-stage Grain-like NFSRs such that the minimal period 2n?1 is achievable for a positive integer n.
查看更多>>摘要：Translating computation tree logic formu-las into Büchi tree automata has been proven to be an effective approach for implementing branching-time model checking. For a more generalized class of lattice-valued (L-valued, for short) computation tree logic formulas, the revelent study has not proceeded yet. We introduce the notion of L-valued alternating Büchi tree automata and achieve the goal of associating each L-valued computation tree logic formula with an L-valued Büchi tree automaton. We show that a satisfiability problem for an L-valued computation tree logic formula can be reduced to one for the language accepted by an L-valued Büchi tree automaton. L-valued alternating Büchi tree automata are the key to the automata-theoretic approach to L-valued computation tree logics, and we also study their expressive power and closure properties.
查看更多>>摘要：Images/videos captured in low-light conditions often present low luminance and contrast. Although the existing low-light enhancement algorithms can improve the subjective perception, color distortion and over-enhancement are extremely obvious, which will disturb the subsequent intelligent analysis. Therefore, a naturalness-preserved low-light enhancement algorithm for intelligent analysis is proposed in this paper. An enhancement model is established in RGB color space. Images of ColorChecker color chart are captured under a series of light conditions. To preserve the naturalness, the factors of the proposed enhancement model are estimated by the images captured in practical illumination environment. Experimental results demonstrate that the proposed algorithm can produce natural enhanced results and improve the performance of vehicle license plate localization and skin color detection compared to the existing algorithms. Furthermore, the proposed algorithm can process the 720p videos at the speed of 28.3 fps on average.
WANG ShengshengDONG RuyiSONG WenzhuoWANG Chuangfeng...
325-330页
查看更多>>摘要：Among qualitative direction relation models, Oriented point relation algebra (OPRAm) is a remarkable model for robot navigation with uncertain direction information. It has great advantages in providing powerful expressions with very limited information compared with other point-based spatial relation models. The original OPRAm is defined in 2D space, and its model and reasoning algorithm are found not applicable in 3D space. We proposed a novel direction relation model named OPRA3Dm to extend the original OPRAm to 3D space, and presented a new reasoning algorithm on Oriented point relation algebra in three dimension (OPRA3Dm). A further study was carried out for composition reasoning on OPRA3Dm. The proposed reasoning algorithm will deduce new information which cannot be directly detected by hardware. The experiment showed the algorithm had some practical significance, it can be applied to the Unmanned aerial vehicle (UAV) navigation and similar scenarios.
查看更多>>摘要：Reassembling fragmented image files is a useful technique to seize image evidence in digital forensics. A key problem of reassembly is how to measure the similarity between the fragments. Most of the measurements are based on the local similarity of the images. We analyze the impact of similarity patterns on the judgment of the adjacency of the fragments and conclude that the horizontal similarity has little help. According to this conclusion, we improve the median edge detector by replacing the horizontal similarity with the left and right diagonal similarity. Furthermore, we improve the sum of differences and Euclidean distance by replacing the mean/sum used in the two measurements with the median. Experimental results verify the analysis of similarity patterns and the improvements.
查看更多>>摘要：S-Transform (ST) is a powerful time-frequency analysis tool with several useful performances. It has been found that ST is sensitive to the sudden change of signal phase and causes a spectrum spread phenomenon, which is often regarded as a shortage. However, a new interpretation of ST spectrum is proposed: the ST can provide a better property of phase hopping detection due to the sensitivity and mono-peak response of ST spectrum. It is a beneficial method to phase hopping estimation. The mathematical relation between the phase hopping angle and the instantaneous value changes of ST spectrum is derived in an explicit representation. This work helps to make a better understanding of the ST spectrum. Besides of the formula derivation, the characteristic is also proved and confirmed by the numerical simulations.
查看更多>>摘要：This study proposes a novel short-range multitarget motion parameter estimation method based on Hough transform. The proposed method can be used for multitarget detection, motion parameter estimation, and data association. In our proposed method, the measured radial distance and Doppler frequency versus time data is mapped to the motion parameter space by Hough transform. The motion parameter space data is binarized to determine the number of targets. The unsupervised nearest neighbor clustering technique is used to determine the search space of targets. The maximum value in each search space is estimated as the motion parameter of the corresponding target. Simulation results show that the proposed method has higher parameter estimation accuracy than that of conventional methods.
查看更多>>摘要：Because of the fluctuation and uncertainty characteristics of wind power, it is difficult to achieve a perfect wind power forecast. The forecast error may lead to an imbalance between the load demand and power supply. The object of recent research on forecast error is to achieve the probability distribution of forecast error based on the statistics of historical data. This statistical error achieved from a probability distribution cannot reveal the real-time condition of wind power. A real-time forecast Error estimate method based on dictionary learning (EEDL) was proposed. In EEDL, several coefficients that have strong relevance to the forecast error are computed. The dictionary learning method is used to extract the eigenvalues of forecast error from these coefficients. Based on the eigenvalues, a real-time error estimation model was built to obtain the forecast error. EEDL was compared to the estimation method based on a Probability distribution function (PDF). The performance of EEDL was also compared to the error estimation method based on a PDF while using different forecast techniques.
查看更多>>摘要：The state-of-the-art speaker recognition system degrades performance rapidly dealing with short-time utterances. It is known to all that identity vectors (i-vectors) extracted from short utterances have large uncertainties and standard Probabilistic linear discriminant analysis (PLDA) method can not exploit this uncertainty to reduce the effect of duration variation. In this work, we use Shared mixture of PLDA (SM-PLDA) to remodel the i-vectors utilizing their uncertainties. SM-PLDA is an improved generative model with a shared intrinsic factor, and this factor can be regarded as an identity vector containing speaker indentification information. This identity vector can be modeled by PLDA. Experimental results are evaluated by both equal error rate and minimum detection cost function. The results conducted on the National institute of standards and technology (NIST) Speaker recognition evaluation (SRE) 2010 extended tasks show that the proposed method has achieved significant improvements compared with i-vector/PLDA and some other advanced methods.
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维普