共查询到20条相似文献，搜索用时 359 毫秒
1.
Samir Abd Elghafar Salaheldin M. Diab Bassiouny M. Sallam Emad S. Hassan Mona Shokair Waleed Al-Nauimy Moawad I. Dessouky El-Sayed M. El-Rabaie Saleh Alshebeili Fathi E. Abd El-Samie 《Journal of The Franklin Institute》2014
This paper presents a new implementation of discrete multi-tone (DMT) systems based on different discrete transforms that include the discrete sine transform (DST), discrete cosine transform (DCT), and discrete wavelet transform (DWT). The implementation also considers time-domain equalization to mitigate channel distortion. Compared to the fast Fourier transform discrete multi-tone (FFT-DMT) system, the proposed implementations have an advantage in that their energy-compaction property helps in reducing the channel effects. The performance of the DST-DMT, DCT-DMT, DWT-DMT, and FFT-DMT systems, employing a time-domain equalizer (TEQ), is investigated in the paper. It has been demonstrated by computer simulations that the proposed implementations outperform the FFT-DMT system and that the utilization of the TEQ can lead to higher bit rates 相似文献
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This paper presents a novel dynamic stochastic resonance (DSR)-based technique for robust extraction of a grayscale logo from a tampered watermarked image. The watermark embedding is done on the singular values (SV) of the discrete cosine transform (DCT) coefficients of the cover image. DSR is then strategically applied during the logo extraction process where the SV of DCT coefficients are tuned following a double-well potential model by utilizing the noise introduced during attacks. The resilience of this technique has been tested in the presence of various noises, geometrical distortions, enhancement, compression, filtering and watermarking attacks. The proposed DSR-based technique for logo extraction gives noteworthy robustness without any significant trade-off in perceptual transparency of the watermarked image. A maximization approach has been adopted for the selection of bistable double-well parameters to establish noise-enhanced resonance. When compared with existing watermark extraction techniques based in SVD, DCT, SVD-DCT domains, as well as with their combination with DSR, the results suggest that remarkable improvement of robustness is achieved by using DSR on singular values of DCT. 相似文献
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离散余弦变换(DCT)是一种映射变换方法,通过把图像中的各个像素从一种空间变换到另一种空间,达到图像压缩的目的。本文对基于DCT变换的图像压缩方法进行了研究,给出了基于DCT变换的图像压缩的基本原理及其实现步骤,并最终给出了图像压缩结果。 相似文献
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《Journal of The Franklin Institute》2018,355(18):9245-9270
This paper deals with noise detection and threshold free on-line denoising procedure for discrete scanning probe microscopy (SPM) surface images using wavelets. In this sense, the proposed denoising procedure works without thresholds for the localisation of noise, as well for the stop criterium of the algorithm. In particular, a proposition which states a constructive structural property of the wavelets tree with respect to a defined seminorm has been proven for a special technical case. Using orthogonal wavelets, it is possible to obtain an efficient localisation of noise and as a consequence a denoising of the measured signal. An on-line denoising algorithm, which is based upon the discrete wavelet transform (DWT), is proposed to detect unavoidable measured noise in the acquired data. With the help of a seminorm the noise of a signal is defined as an incoherent part of a measured signal and it is possible to rearrange the wavelet basis which can illuminate the differences between its coherent and incoherent part. In effect, the procedure looks for the subspaces consisting of wavelet packets characterised either by small or opposing components in the wavelet domain. Taking real measurements the effectiveness of the proposed denoising algorithm is validated and compared with Gaussian FIR- and Median filter. The proposed method was built using the free wavelet toolboxes from the WaveLab 850 library of the Stanford University (USA). 相似文献
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提出了一种新的基于视频压缩编码的动态图像水印方案。在嵌入水印时,充分考虑动态图像压缩编码的特性,对帧内编码帧(I帧),将水印信息嵌入到DCT低频系数中;而对帧间编码帧(P,B帧),结合动态补偿/离散余弦变换(MC/DCT)混介编码,把水印信息嵌入到运动补偿后的残差图像的自流成分中。同时,在水印嵌入时,采用扩频技术与多维水印相结合的方法,并通过相关检测的方法判断水印的存在。由于水印的检测是对视频码流直接实施的,不需要对压缩数据进行完全解码,从而大大降低了计算量,提高了视频数据水印的适用性。 相似文献
7.
C. Maharajan R. Raja Jinde Cao G. Rajchakit 《Journal of The Franklin Institute》2018,355(11):4727-4754
In this paper, the global robust exponential stability problem for a class of uncertain inertial-type BAM neural networks with both time-varying delays is focused through Lagrange sense. The existence of time-varying delays in discrete and distributed terms is explored with the availability of lower and upper bounds of time-varying delays. Firstly, we transform the proposed inertial BAM neural networks to usual one. Secondly, by the aid of LKF, stability theory, integral inequality, some novel sufficient conditions for the global robust exponential stability of the addressed neural networks are obtained in terms of linear matrix inequalities, which can be easily tested in practice by utilizing LMI control toolbox in MATLAB software. Furthermore, many comparisons of proposed work are listed with some existing literatures to get less conservatism. Finally, two numerical examples are provided to demonstrate the advantages and superiority of our theoretical outcomes. 相似文献
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中国公立医院医生的工作投入度和绩效不但直接影响了患者对服务水平和质量的感知，也代表了中国整体医疗水平和服务质量。探究这一群体的职业使命感对工作投入度的影响，以及这种影响是如何发生的，不但是关乎每个人的现实问题，也是了解中国特定国情下的医生群体职业心理的理论问题。论文以自我决定理论和生涯构建理论为基础，构建了“职业使命感—职业认同—工作投入”的假设模型，使用403份公立医院医生的有效样本的统计分析表明：博士及以上学历的医生职业使命感显著高于硕士学历和本科及以下学历，共产党员医生的职业使命感水平显著高于非党员医生；高级职务的医生的职业使命感显著高于中低职务的医生。医生的职业使命感与工作投入呈显著的正相关关系，职业认同在职业使命感和工作投入之间起部分中介作用。论文最后提出通过增强医生职业使命感和职业认同的双路径来提高医生的工作投入水平，构建和谐医患关系。 相似文献
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提出了一种提升小波变换和DCT变换相结合的图像融合算法。这种算法并不依赖于对方差,而是直接使用DCT变化和小波变化分别对高频部分、低频部分进行特征提取。实验表明,这种新的融合技术与传统算法相比,不但提高了图像的信噪比,更加保留了边缘的信息细节,同时也提高了处理效率,减少了使用时间,具有较高得实用价值。 相似文献
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This paper presents a moving horizon estimation approach for the multirate sampled-data system with unknown time-delay sequence. To estimate the unknown variables of interest, two main challenging issues need to be addressed: (a) synthesizing the multirate input and output data for state estimation, (b) simultaneously estimating the continuous state and discrete time-delay sequence. In this work a moving horizon estimation based approach is developed to tackle these issues. The proposed approach can simultaneously estimate both the continuous states and discrete time-delay sequence for dynamic systems. The effects of different noise level on the estimation of continuous states and discrete time-delay sequence are analyzed. The effectiveness of this method is illustrated through a simulation study. 相似文献
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Recently the Wigner distribution has been shown to be a potentially useful tool for analysing the time varying frequency domain phenomenon. In this paper, some of the salient features of the Wigner distribution are presented; properties of this important discrete distribution are derived, and an efficient digital implementation is presented. Effective Wigner throughput rates, in excess of those obtainable with an equivalent length FFT, are shown to be feasible. In particular, the Wigner distribution is studied in the context of enhancing speech analysis and recognition systems. It is suggested that this class of distribution is consistent with the mechanics of human speech and, using experimentation, produces a very robust spectral signature. This enriched data space can be used to uncover some frequency domain attributes of human speech which may be lost using a discrete Fourier transform. 相似文献
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本文提出了一种离散余弦变换电路VLSI实现的可测试性设计。它采用基于算法结构变换的并行实现,所用乘法的数量大大减少,降低了硬件面积占用和功率消耗。为提高DCT的可靠性,在本设计中加入可测性设计方法,采用一种新的内建自测试(BIST)技术。实验表明该设计对运算器的内部结构和运算速度影响小,并具有较高的故障覆盖率。本文的方法适用于高可靠性要求下的数字信号处理的VLSI实现。 相似文献
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本文基于工作投入和自我效能理论，对影响网络众包参与者创造力的关键路径进行分析，构建了网络众包参与者创造力影响因素模型。运用SEM模型对Kaggle网络众包竞赛平台的600位众包数据分析家的问卷调查数据进行实证检验，研究发现：（1）网络众包参与者的自我效能和工作投入都可以直接影响个人的创造力水平；（2）工作投入中的情感投入和认知投入对创造力有正向影响，而生理投入有负向影响；（3）自我效能中的领域任务自我效能和互动学习自我效能对创造力都有正向影响；（4）工作投入中的情感投入和认知投入在自我效能与创造力之间有中介作用；（5）自我效能中的领域任务自我效能和互动学习自我效能在工作投入与创造力之间也有中介作用。 相似文献
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In this paper, an algorithm is developed to apply Hann, Hamming, Blackman and related windows directly in the transform domain for the discrete cosine transform and discrete sine transform. These algorithms are useful in applications where windowing is required in order to minimize edge effects caused by implicit symmetries in the transform domain that are not replicated in the real-world data. Examples of such applications include data communication, adaptive system identification and filtering, real-time analysis of financial market data, etc. Software implementations in C language are also given. 相似文献
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《Information processing & management》2022,59(1):102743
Multi-modal hashing can encode the large-scale social geo-media multimedia data from multiple sources into a common discrete hash space, in which the heterogeneous correlations from multiple modalities could be well explored and preserved into the objective semantic-consistent hash codes. The current researches on multi-modal hashing mainly focus on performing common data reconstruction, but they fail to effectively distill the intrinsic and consensus structures of multi-modal data and fully exploit the inherent semantic knowledge to capture semantic-consistent information across multiple modalities, leading to unsatisfactory retrieval performance. To facilitate this problem and develop an efficient multi-modal geographical retrieval method, in this article, we propose a discriminative multi-modal hashing framework named Cognitive Multi-modal Consistent Hashing (CMCH), which can progressively pursue the structure consensus over heterogeneous multi-modal data and simultaneously explore the informative transformed semantics. Specifically, we construct a parameter-free collaborative multi-modal fusion module to incorporate and excavate the underlying common components from multi-source data. Particularly, our formulation seeks for a joint multi-modal compatibility among multiple modalities under a self-adaptive weighting manner, which can take full advantages of their complementary properties. Moreover, a cognitive self-paced learning policy is further leveraged to conduct progressive feature aggregation, which can coalesce multi-modal data onto the established common latent space in a curriculum learning mode. Furthermore, deep semantic transform learning is elaborated to generate flexible semantics for interactively guiding collaborative hash codes learning. An efficient discrete learning algorithm is devised to address the resulting optimization problem, which obtains stable solutions when dealing with large-scale multi-modal retrieval tasks. Sufficient experiments performed on four large-scale multi-modal datasets demonstrate the encouraging performance of the proposed CMCH method in comparison with the state-of-the-arts over multi-modal information retrieval and computational efficiency. The source codes of this work could be available at https://github.com/JunfengAn1998a/CMCH . 相似文献
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《Information processing & management》2020,57(6):102339
This paper aims to establish digital forensics and data exploration as a methodology for supporting archival practice and research into a filmmaker's creative processes. We approach this by exploring the digital legacy hard drives of the late artist Stephen Dwoskin (1939–2012), who is recognised as an influential filmmaker at the forefront of the shift from analogue to digital film production. The research findings of this case study show that digital forensics is effective in extracting a timeline of hard drive activities, data that can be explored to reveal clues about the artist's personal/professional history, stages of creative processes, and technical environment. The paper further demonstrates how this is related to current thinking around user-centred archival workflow and understanding of creative processes. The broader impact of the work for advancing digital archiving and research into creative processes is highlighted, concluding with a discussion of how, going forward, the approach can be coupled with deeper content analysis to reveal what influences editing choices taking place over time. 相似文献
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Quasi-power functionals have been traditionally derived through the Method of Weighted Residuals (MWR) and used as the starting formulation for the finite element method. In this paper, we derive similar but more complete functionals for potential fields through a novel approach. We first form discrete quasi-power functions by applying Tellegen's theorem to the Graph-Theoretic Field Model (GTFM) and then obtain the continuous model quasi-power functionals by applying a limiting process to the discrete counterpart. The procedure herein is in marked contrast to the MWR whereby quasi-power functionals are derived by applying mathematical operations to the partial differential system. The procedure can be used with fields with anisotropy, non-linearities and coupled processes, although the example fields used within are linear and isotropic. This paper is a sequel to similar derivations for Green's identities and variational formulations. 相似文献
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《Journal of The Franklin Institute》2022,359(12):6392-6437
This work realizes lag quasi-synchronization of incommensurate fractional-order memristor-based neural networks (FMNNs) with nonidentical characteristics via quantized control. The motivations behind this research work are threefold: (1) quantized controllers, which generate discrete control signals, can be more easily realized in computers than non-quantized controllers, and can consume smaller communication capacity; (2) incommensurate orders in a single FMNN and nonidentical characteristics in drive-response FMNNs are inescapable due to the differences among the circuit elements used to implement FMNNs; (3) convergence analysis of delayed incommensurate fractional-order nonlinear systems, which is the basis for the derivation of synchronization criterion, has not been handled perfectly. As an effective tool for convergence analysis of delayed incommensurate fractional-order nonlinear systems, especially for estimation of ultimate state bound, a vector fractional Halanay inequality is established at first. Then, a quantized synchronization controller, in which the dead-zone is introduced into some logarithmic quantizers to avoid chattering phenomenon, is designed. By means of vector Lyapunov function together with the newly derived vector fractional Halanay inequality, the synchronization criterion is proved theoretically. Lastly, numerical simulations supplementarily illustrate the correctness of the synchronization criterion. In contrast with the hypotheses in the relevant literature, the hypotheses in this paper are weaker. 相似文献
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《Journal of The Franklin Institute》2022,359(17):9886-9901
This paper considers the output feedback sliding-mode control for an uncertain linear system with unstable zeros. Based on a frequency shaping design, a dynamic-gain observer is used for state estimation of an uncertain system. This paper confirms that (1) state estimation is globally stable in a practical sense, (2) the resultant error can be arbitrarily small with respect to the system uncertainties, and (3) the proposed sliding-mode control can drive the uncertain system state into an arbitrarily small residual set around the origin, such that the size of residual set is controlled by the filter design. Moreover, the proposed control design is inherently robust to measurement noise; the effect of measurement noise can effectively be attenuated without any additional work. 相似文献