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A secure image steganography algorithm based on least significant bit and integer wavelet transform 被引量:4
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作者 ELSHAZLY Emad ABDELWAHAB Safey +3 位作者 ABOUZAID Refaat ZAHRAN Osama ELARABY Sayed ELKORDY Mohamed 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2018年第3期639-649,共11页
The rapid development of data communication in modern era demands secure exchange of information. Steganography is an established method for hiding secret data from an unauthorized access into a cover object in such a... The rapid development of data communication in modern era demands secure exchange of information. Steganography is an established method for hiding secret data from an unauthorized access into a cover object in such a way that it is invisible to human eyes. The cover object can be image, text, audio,or video. This paper proposes a secure steganography algorithm that hides a bitstream of the secret text into the least significant bits(LSBs) of the approximation coefficients of the integer wavelet transform(IWT) of grayscale images as well as each component of color images to form stego-images. The embedding and extracting phases of the proposed steganography algorithms are performed using the MATLAB software. Invisibility, payload capacity, and security in terms of peak signal to noise ratio(PSNR) and robustness are the key challenges to steganography. The statistical distortion between the cover images and the stego-images is measured by using the mean square error(MSE) and the PSNR, while the degree of closeness between them is evaluated using the normalized cross correlation(NCC). The experimental results show that, the proposed algorithms can hide the secret text with a large payload capacity with a high level of security and a higher invisibility. Furthermore, the proposed technique is computationally efficient and better results for both PSNR and NCC are achieved compared with the previous algorithms. 展开更多
关键词 image steganography image processing integer wavelet transform
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A new all-zero 4×4 block determination rule for integer transform and quantization in AVS-M encoder 被引量:1
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作者 LIU Dong-hua CHEN Yi-qiang 《Journal of Zhejiang University-Science A(Applied Physics & Engineering)》 SCIE EI CAS CSCD 2006年第z1期89-94,共6页
A new all-zero block determination rule was used to reduce the complexity of the AVS-M encoder. It reuses the sum of absolute difference of 4x4 block obtained from motion estimation or intra prediction as parameters s... A new all-zero block determination rule was used to reduce the complexity of the AVS-M encoder. It reuses the sum of absolute difference of 4x4 block obtained from motion estimation or intra prediction as parameters so that the determination threshold need to be computed only once when quantization parameter (QP) is invariable for given video sequence. This method avoids a lot of computation for transform, quantization, inverse transform, inverse quantization and block reconstruction. Simulation results showed that it can save about 20%~50% computation without any video quality degradation. 展开更多
关键词 AVS-M integer DCT transform QUANTIZATION All-zero 4x4 block PSNR
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Seismic data compression based on integer wavelet transform 被引量:1
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作者 WANG Xi-zhen(王喜珍) TENG Yun-tian(滕云田) +1 位作者 GAO Meng-tan(高孟潭) JIANG Hui(姜慧) 《Acta Seismologica Sinica(English Edition)》 CSCD 2004年第z1期123-128,共6页
Due to the particularity of the seismic data, they must be treated by lossless compression algorithm in some cases. In the paper, based on the integer wavelet transform, the lossless compression algorithm is studied.... Due to the particularity of the seismic data, they must be treated by lossless compression algorithm in some cases. In the paper, based on the integer wavelet transform, the lossless compression algorithm is studied. Comparing with the traditional algorithm, it can better improve the compression rate. CDF (2, n) biorthogonal wavelet family can lead to better compression ratio than other CDF family, SWE and CRF, which is owe to its capability in can- celing data redundancies and focusing data characteristics. CDF (2, n) family is suitable as the wavelet function of the lossless compression seismic data. 展开更多
关键词 lossless compression integer wavelet transform lifting scheme biorthogonal wavelet
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An Approach to Integer Wavelet Transform for Medical Image Compression in PACS
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作者 YANG Yan ZHANG Dong 《Wuhan University Journal of Natural Sciences》 CAS 2000年第2期204-206,共3页
We study an approach to integer wavelet transform for lossless compression of medical image in medical picture archiving and communication system (PACS). By lifting scheme a reversible integer wavelet transform is gen... We study an approach to integer wavelet transform for lossless compression of medical image in medical picture archiving and communication system (PACS). By lifting scheme a reversible integer wavelet transform is generated, which has the similar features with the corresponding biorthogonal wavelet transform. Experimental results of the method based on integer wavelet transform are given to show better performance and great applicable potentiality in medical image compression. 展开更多
关键词 Key words integer wavelet transform lifting scheme lossless compression PACS
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A Recursive High Payload Reversible Data Hiding Using Integer Wavelet and Arnold Transform
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作者 Amishi Mahesh Kapadia P.Nithyanandam 《Intelligent Automation & Soft Computing》 SCIE 2023年第1期537-552,共16页
Reversible data hiding is an information hiding technique that requires the retrieval of the error free cover image after the extraction of the secret image.We suggested a technique in this research that uses a recurs... Reversible data hiding is an information hiding technique that requires the retrieval of the error free cover image after the extraction of the secret image.We suggested a technique in this research that uses a recursive embedding method to increase capacity substantially using the Integer wavelet transform and the Arnold transform.The notion of Integer wavelet transforms is to ensure that all coefficients of the cover images are used during embedding with an increase in payload.By scrambling the cover image,Arnold transform adds security to the information that gets embedded and also allows embedding more information in each iteration.The hybrid combination of Integer wavelet transform and Arnold transform results to build a more efficient and secure system.The proposed method employs a set of keys to ensure that information cannot be decoded by an attacker.The experimental results show that it aids in the development of a more secure storage system and withstand few tampering attacks The suggested technique is tested on many image formats,including medical images.Various performance metrics proves that the retrieved cover image and hidden image are both intact.This System is proven to withstand rotation attack as well. 展开更多
关键词 Reversible data hiding(RDH) integer wavelet transforms(IWT) arnold transform PAYLOAD embedding and extraction
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Fragile Audio Watermarking with Perfect Restoration Capacity Based on an Adapted Integer Transform
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作者 LUO Xinrong XIANG Shijun 《Wuhan University Journal of Natural Sciences》 CAS 2014年第6期497-504,共8页
We propose a novel audio watermarking scheme which can recover the original audio carrier perfectly if the watermarked audio is modified. Besides, we can adjust the maximum tampered rate allowed and the quality of wat... We propose a novel audio watermarking scheme which can recover the original audio carrier perfectly if the watermarked audio is modified. Besides, we can adjust the maximum tampered rate allowed and the quality of watermarked audio flexibly as required. In the scheme, an efficient generalized integer transform is improved to embed watermark data which are composed of least significant bits(LSBs) of averages in each patch, reference-bits and check-bits. LSBs are needed in the inverse transform. Then, by comparing the extracted check-bits and calculated ones, the modified area can be localized. Finally, reliable reference-bits and samples data help us reconstruct the original audio without errors. The efficiency of the proposed method is theoretically and experimentally verified. 展开更多
关键词 error-free restoration integer transform fragile audio watermarking
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A High-performance Low Cost Inverse Integer Transform Architecture for AVS Video Standard
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作者 李宇飞 王琴 付宇卓 《Journal of Shanghai Jiaotong university(Science)》 EI 2008年第1期116-121,共6页
A high-performance, low cost inverse integer transform architecture for advanced video standard (AVS) video coding standard was presented. An 8 × 8 inverse integer transform is required in AVS video system whic... A high-performance, low cost inverse integer transform architecture for advanced video standard (AVS) video coding standard was presented. An 8 × 8 inverse integer transform is required in AVS video system which is compute-intensive. A hardware transform is inevitable to compute the transform for the real-time application. Compared with the 4 × 4 transform for H.264/AVC, the 8 × 8 integer transform is much more complex and the coefficient in the inverse transform matrix Ts is not inerratic as that in H.264/AVC. Dividing the Ts into matrix Ss and Rs, the proposed architecture is implemented with the adders and the specific CSA-trees instead of multipliers, which are area and time consuming. The architecture obtains the data processing rate up to 8 pixels per-cycle at a low cost of area. Synthesized to TSMC 0.18 μm COMS process, the architecture attains the operating frequency of 300 MHz at cost of 34 252 gates with a 2-stage pipeline scheme. A reusable scheme is also introduced for the area optimization, which results in the operating frequency of 143 MHz at cost of only 19 758 gates. 展开更多
关键词 inverse integer transform high-definitioin television (HDTV) carry-save adder (CSA) tree pipeline advanced video standard (AVS)
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A COMPRESSION ALGORITHM FOR ECG BASED ON INTEGER LIFTING SCHEME WAVELET TRANSFORM
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作者 Zhang Kunyan Guo Yinjing Lü Wenhong Sun Jinping Wang Xiuzhen 《Journal of Electronics(China)》 2007年第5期674-678,共5页
In view of the shortcomes of conventional ElectroCardioGram (ECG) compression algo- rithms,such as high complexity of operation and distortion of reconstructed signal,a new ECG compression encoding algorithm based on ... In view of the shortcomes of conventional ElectroCardioGram (ECG) compression algo- rithms,such as high complexity of operation and distortion of reconstructed signal,a new ECG compression encoding algorithm based on Set Partitioning In Hierarchical Trees (SPIHT) is brought out after studying the integer lifting scheme wavelet transform in detail.The proposed algorithm modifies zero-tree structure of SPIHT,establishes single dimensional wavelet coefficient tree of ECG signals and enhances the efficiency of SPIHT-encoding by distributing bits rationally,improving zero-tree set and ameliorating classifying method.For this improved algorithm,floating-point com- putation and storage are left out of consideration and it is easy to be implemented by hardware and software.Experimental results prove that the new algorithm has admirable features of low complexity, high speed and good performance in signal reconstruction.High compression ratio is obtained with high signal fidelity as well. 展开更多
关键词 Electro Cardio Gram (ECG) integer lifting scheme Wavelet transform Set Partitioning InHierarchical Trees (SPIHT)
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SAR Image Compression Using Integer to Integer Transformations, Dimensionality Reduction, and High Correlation Modeling
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作者 Sergey Voronin 《Journal of Computer and Communications》 2022年第2期19-32,共14页
In this document, we present new techniques for near-lossless and lossy compression of SAR imagery saved in PNG and binary formats of magnitude and phase data based on the application of transforms, dimensionality red... In this document, we present new techniques for near-lossless and lossy compression of SAR imagery saved in PNG and binary formats of magnitude and phase data based on the application of transforms, dimensionality reduction methods, and lossless compression. In particular, we discuss the use of blockwise integer to integer transforms, subsequent application of a dimensionality reduction method, and Burrows-Wheeler based lossless compression for the PNG data and the use of high correlation based modeling of sorted transform coefficients for the raw floating point magnitude and phase data. The gains exhibited are substantial over the application of different lossless methods directly on the data and competitive with existing lossy approaches. The methods presented are effective for large scale processing of similar data formats as they are heavily based on techniques which scale well on parallel architectures. 展开更多
关键词 SAR Imagery integer-to-integer transforms Dimensionality Reduction High Correlation Modeling Lossy and Lossless Compression
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Integer Wavelet-Based Image Interpolation in Lifting Structure for Image Resolution Enhancement
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作者 Chin-Yu Chen Shu-Mei Guo +1 位作者 Ching-Hsuan Tsai Jason Sheng-Hong Tsai 《Applied Mathematics》 2018年第10期1156-1178,共23页
A floating-point wavelet-based and an integer wavelet-based image interpolations in lifting structures and polynomial curve fitting for image resolution enhancement are proposed in this paper. The proposed prediction ... A floating-point wavelet-based and an integer wavelet-based image interpolations in lifting structures and polynomial curve fitting for image resolution enhancement are proposed in this paper. The proposed prediction methods estimate high-frequency wavelet coefficients of the original image based on the available low-frequency wavelet coefficients, so that the original image can be reconstructed by using the proposed prediction method. To further improve the reconstruction performance, we use polynomial curve fitting to build relationships between actual high-frequency wavelet coefficients and estimated high-frequency wavelet coefficients. Results of the proposed prediction algorithm for different wavelet transforms are compared to show the proposed prediction algorithm outperforms other methods. 展开更多
关键词 IMAGE Compression IMAGE Interpolation WAVELET transform integer WAVELET transform POLYNOMIAL Curve Fitting
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输电网拓扑优化的MISOCP模型及邻域搜索加速求解方法 被引量:1
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作者 李佩杰 玉君连 孙志媛 《电力系统自动化》 北大核心 2025年第3期170-177,共8页
电力系统中引发潮流过载等安全问题的场景日益增多,拓扑优化可通过网络拓扑转换来消除潮流过载问题,但其复杂的模型转换逻辑与大规模整数变量的引入,显著增加了建模的复杂度和求解的难度。为此,文中提出一种考虑主接线拓扑转换的输电网... 电力系统中引发潮流过载等安全问题的场景日益增多,拓扑优化可通过网络拓扑转换来消除潮流过载问题,但其复杂的模型转换逻辑与大规模整数变量的引入,显著增加了建模的复杂度和求解的难度。为此,文中提出一种考虑主接线拓扑转换的输电网拓扑优化方法。首先,在通用变电站主接线拓扑转换模型的基础上,建立了混合整数二阶锥规划(MISOCP)的模型。该模型不仅可以考虑拓扑变换对有功潮流的影响,还可计及无功平衡和电压的约束,解决了以往基于直流潮流的拓扑优化模型消除有功过载时调控方式可能偏乐观甚至恶化电压指标的问题。此外,为高效求解所提模型,提出一种邻域搜索加速求解方法。最后,采用IEEE 14、IEEE 118和波兰2383节点系统进行仿真计算。结果表明,所提优化模型能够经济、有效地解决线路过载问题,所提求解方法能够提高所提模型的求解效率。 展开更多
关键词 拓扑转换 混合整数二阶锥规划 邻域搜索 拓扑优化
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High-performance multi-transform architecture for H.264/AVC
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作者 王刚 王庆 +1 位作者 李冰 陈锐 《Journal of Southeast University(English Edition)》 EI CAS 2013年第3期276-281,共6页
In order to increase the hardware utilization and minimize the chip area a multi-transform coding architecture which includes 4 ×4 forward integer transform 4 ×4 inverse integer transform 4 ×4 Hadamard ... In order to increase the hardware utilization and minimize the chip area a multi-transform coding architecture which includes 4 ×4 forward integer transform 4 ×4 inverse integer transform 4 ×4 Hadamard transform and 2 ×2 Hadamard transform is proposed. By simplifying these transforms and exploring their similarities the proposed design merges the architectures processing individual transforms into a high-performance multi-transform coding architecture.Using a semiconductor manufacturing international corporation SMIC 0.18 μm complementary metal oxide semiconductor CMOS technology the proposed architecture achieves the maximum operating clock frequency of 200 MHz and the throughput rate of 800 ×106 pixel/s with the hardware cost of 3 704 gates.The results demonstrate that the data throughput rate per unit area DTUA of this design is at least 40.28%higher than that of the reference design.This design can meet the requirements of real-time decoding digital cinema video 4 096 ×2 048@30 Hz at 62.9 MHz which helps to reduce the power consumption. 展开更多
关键词 H. 264/AVC multi-transform architecture Hadamard transform integer transform
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采用IWT和自适应伪Zernike矩的鲁棒可逆水印方案
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作者 高光勇 花锋 +2 位作者 王敏 赵传信 夏志华 《电子学报》 北大核心 2025年第5期1571-1583,共13页
鲁棒可逆水印(Robust Reversible Watermarking,RRW)是近年来信息隐藏领域中一个非常新颖和有价值的研究方向,无论是在图像的版权认证还是高保真领域都有较好发展前景.然而,现有的RRW方案抵抗几何变换、常见攻击以及联合攻击的鲁棒性较... 鲁棒可逆水印(Robust Reversible Watermarking,RRW)是近年来信息隐藏领域中一个非常新颖和有价值的研究方向,无论是在图像的版权认证还是高保真领域都有较好发展前景.然而,现有的RRW方案抵抗几何变换、常见攻击以及联合攻击的鲁棒性较差.为了解决这些问题,本文提出一种采用整数小波变换(Integer Wavelet Transfor⁃mation,IWT)和自适应伪Zernike矩的鲁棒可逆水印方案,该方案在提升水印不可感知性的同时具有可逆性和鲁棒性.首先,由原始图像通过IWT得到低频区域计算生成伪Zernike矩的幅度,然后用自适应归一化方法选择合适的矩,再通过改进的带抖动补偿量化索引调制技术将鲁棒水印嵌入到合适的伪Zernike矩中,对带水印的伪Zernike矩进行重构生成水印图像.最后计算其hash值,并将其与水印图像和原始图像之间的误差、重构误差组成辅助信息嵌入水印图像中,在无攻击的情况下实现载体图像的可逆还原.实验结果表明,本方案对常见信号处理和几何变换攻击具有鲁棒性,相较于近几年提出的RRW方案,本方案在不可见性下实现了更好的鲁棒性. 展开更多
关键词 鲁棒水印 伪ZERNIKE矩 整数小波变换 可逆性 信息隐藏
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基于游程编码和颜色转换的图像安全传输研究
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作者 赵杨宇 姚丙君 +1 位作者 汤震宇 平萍 《计算机仿真》 2025年第5期147-152,220,共7页
由于电力巡检缺陷图像在传输过程中易被攻击者获取和利用,从而对电力公司造成潜在威胁。研究首次结合频域和空域提出了一种基于游程编码和颜色转换的电力巡检缺陷图像安全传输方案。首先,游程编码被首次用于图像隐藏中对缺陷图像进行编... 由于电力巡检缺陷图像在传输过程中易被攻击者获取和利用,从而对电力公司造成潜在威胁。研究首次结合频域和空域提出了一种基于游程编码和颜色转换的电力巡检缺陷图像安全传输方案。首先,游程编码被首次用于图像隐藏中对缺陷图像进行编码,这可降低图像嵌入对掩体图像像素值的损害。然后,在频域下,秘密信息被嵌入到频域的子带中。最后,在空域下,颜色转换被使用以提高含密图像的质量。在模拟实验中,上述方法含密图像的PSNR和MSSIM高于经典的图像隐藏方法,且含密图像能够抵抗残差分析和直方图分析。多方面的实验结果表明该方案在保证缺陷图像无损恢复的前提下显著提高了含密图像的质量,增强了含密图像在不安全网络中传输的安全性。 展开更多
关键词 电力巡检缺陷图像 整数小波变换 游程编码 颜色转换 图像隐藏
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面向故障恢复的配电网实时拓扑辨识技术研究
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作者 杨乐 徐正宏 +2 位作者 朱莹 常颢 鞠玲 《电力需求侧管理》 2025年第3期113-118,共6页
随着分布式能源接入配电网,其结构愈发复杂,故障率也有所增加。配电网故障恢复有助于快速恢复供电,提高电力系统的稳定性和可靠性。配变智能终端(distribution transformer supervisory terminal unit,TTU)的大量安装,为配网故障恢复提... 随着分布式能源接入配电网,其结构愈发复杂,故障率也有所增加。配电网故障恢复有助于快速恢复供电,提高电力系统的稳定性和可靠性。配变智能终端(distribution transformer supervisory terminal unit,TTU)的大量安装,为配网故障恢复提供了数据支撑。重点研究了考虑TTU数据量测误差的配电网实时拓扑辨识技术。首先,在分析TTU量测数据的基础上,构建了以功率残差最小为目标的拓扑辨识优化方程。然后,针对优化方程中的混合整数规划问题以及约束的非线性化问题,将方程转换为二次规划问题使其方便求解,并提出了对个别误差较大的量测数据进行修正的方法。最后,通过算例验证了所提出的拓扑辨识算法的鲁棒性和性能以及误差修正算法的有效性。 展开更多
关键词 配变智能终端 拓扑辨识 二次规划 整数规划
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Explicit Expression of Foldy-Wouthuysen Transformation
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作者 WANG An-min 《Chinese Physics Letters》 SCIE CAS CSCD 1998年第4期235-237,共3页
The general,explicit and formally closed expression of arbitrary n-times Foldy-Wouthuysen transformations is clearly and strictly derived out.It is proved that if transformed Hamiltonian needs to be approximated to th... The general,explicit and formally closed expression of arbitrary n-times Foldy-Wouthuysen transformations is clearly and strictly derived out.It is proved that if transformed Hamiltonian needs to be approximated to the order 1/m^(K) or mv^(2K) when to involve the orders of the operators,then to make N=[(K+1)/2]-times Foldy-Wouthuysen transformations is just enough(“[...]”means to take the part of integer).An example in non-relativistic quantum chromodynamics is given. 展开更多
关键词 transformATION integer OPERATORS
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城市轨道交通乘务交路方案编制的禁忌搜索优化方法 被引量:2
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作者 邓连波 谢子若 +2 位作者 甘书怀 张颖 任绍坤 《北京交通大学学报》 CAS CSCD 北大核心 2024年第4期164-171,共8页
针对城市轨道交通普遍采用轮乘制、日班和两头班混合等特点,对城市轨道交通乘务交路方案编制问题进行研究,旨在降低乘务成本并提高乘务效率.首先,通过分析城市轨道交通乘务交路方案的构成要素,考虑值乘时长、值乘片段接续时间和接续地... 针对城市轨道交通普遍采用轮乘制、日班和两头班混合等特点,对城市轨道交通乘务交路方案编制问题进行研究,旨在降低乘务成本并提高乘务效率.首先,通过分析城市轨道交通乘务交路方案的构成要素,考虑值乘时长、值乘片段接续时间和接续地点等要求,构建值乘片段、值乘任务构成和乘务规则约束,由此建立以乘务组数量和总接续时间等综合指标最小化为目标函数的多目标0-1整数规划模型.然后,针对该模型设计禁忌搜索(Tabu Search,TS)算法进行求解,以先到先走(First-In-First-Out,FIFO)的就近指派原则得到初始解,并设计4种邻域变换策略,以提高邻域解的多样性,并构建基于多邻域结构的禁忌搜索求解算法,实现对乘务交路方案的优化.最后,以广州地铁7号线的乘务交路方案为例进行实例验证.研究结果表明:优化方案较实际运营方案的乘务作业段数和总接续时间分别降低了20%和4.94%,每个乘务作业段值乘列车数量从8.2列增加到10.3列,有效驾驶时间从5.4 h增加到5.8 h,优化方案的各项指标均得到显著提升.研究成果可以为城市轨道交通乘务计划编制提供理论和方法支持. 展开更多
关键词 城市轨道交通 乘务交路计划 多目标0-1整数规划 禁忌搜索算法 多邻域变换
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基于整数U变换的图像压缩方法 被引量:1
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作者 袁茜茜 蔡占川 +1 位作者 石武祯 尹文楠 《华南理工大学学报(自然科学版)》 EI CAS CSCD 北大核心 2024年第10期124-134,共11页
整数变换方法因其较快的计算速度被国际图像和视频编码标准广泛采纳。现有基于连续正交函数系的整数变换方法不仅难以获得原始变换的准确整数形式,而且无法克服在非连续信号表达时出现的吉布斯震荡现象,降低了重构图像质量。为此,文中... 整数变换方法因其较快的计算速度被国际图像和视频编码标准广泛采纳。现有基于连续正交函数系的整数变换方法不仅难以获得原始变换的准确整数形式,而且无法克服在非连续信号表达时出现的吉布斯震荡现象,降低了重构图像质量。为此,文中提出了基于非连续正交U系统的整数变换算法及其图像压缩方法。首先,采用分段积分法和施密特正交化法计算出U系统的2维正交变换矩阵,提取行向量的缩放因子得到整数矩阵;接着,建立整数U矩阵的可逆正交变换方法,使用整数矩阵将离散图像信息的能量集中到少量数据集,同时将缩放因子与量化步骤合并以减轻计算负担;然后,采用矩阵分解法将整数U矩阵分解为稀疏矩阵的乘积,从而实现图像变换的快速计算;最后,设计基于整数U变换模块和逆变换模块的图像压缩方法,用于减轻图像存储和传输压力。实验结果表明:文中方法与其他相关方法相比,可以降低图像可逆变换的截断误差;在图像和视频压缩实验中,在相同的压缩率下文中方法获得的压缩图像质量更高,而且快速变换方法可以有效地节省运算时间。 展开更多
关键词 图像压缩 整数变换 非连续正交U系统 吉布斯现象 快速计算
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适合水声隐蔽通信的图像隐写算法
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作者 王文锦 李庆忠 《计算机辅助设计与图形学学报》 EI CSCD 北大核心 2024年第8期1263-1271,共9页
为了实现水声信道场景中的快速、安全信息隐藏,提出一种基于杜鹃搜索(CS)与整数小波变换的水声隐蔽通信下图像隐写算法.首先对待嵌入的水下图像进行交织打包处理,生成秘密信息码流,提高传输差错检测和恢复能力;然后将载体图像划分为不... 为了实现水声信道场景中的快速、安全信息隐藏,提出一种基于杜鹃搜索(CS)与整数小波变换的水声隐蔽通信下图像隐写算法.首先对待嵌入的水下图像进行交织打包处理,生成秘密信息码流,提高传输差错检测和恢复能力;然后将载体图像划分为不重叠的块,对每个子块应用整数小波变换进行处理,既可以节省CS搜索空间,又能提高算法的寻优性能;再对高频子带系数的嵌入位置矩阵进行混沌置乱,使用CS选择最优密钥获得秘密信息的最优匹配位置,产生最佳质量的隐秘图像;最后对提取出的秘密信息采用传输差错检测与恢复措施,提高水声信道传输后水下图像的重建质量.在标准测试图像数据集SIPI上进行实验结果表明,当信息嵌入容量为0.5 bit/像素时,所提算法生成隐秘图像的平均峰值信噪比(PSNR)达到52.80 dB,平均数据结构相似性指数度量为0.9999,优于现有算法,满足水下通信安全性、实时性的要求;当丢包率高达20%时,重建图像的PSNR超过35.9 dB,在0.8%的混合误码率下,重建图像的PSNR超过36 dB,具有应对恶劣水下噪声环境下传输差错的检测与恢复能力. 展开更多
关键词 整数小波变换 杜鹃搜索 水声通信 图像隐写
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低压配电台区移动储能系统优化调度方法 被引量:6
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作者 孙义豪 李科 +3 位作者 许长清 马杰 孟赫 王凯奇 《电力系统及其自动化学报》 CSCD 北大核心 2024年第12期37-44,共8页
日益增长的负荷需求和分布式可再生能源的广泛接入使得配电网运行波动剧增。为此,本文提出一种两阶段移动储能系统日前运行调度方法,以解决低压配电台区变压器重载和分布式可再生能源消纳问题。首先,构建表征多台区转移路径的移动储能... 日益增长的负荷需求和分布式可再生能源的广泛接入使得配电网运行波动剧增。为此,本文提出一种两阶段移动储能系统日前运行调度方法,以解决低压配电台区变压器重载和分布式可再生能源消纳问题。首先,构建表征多台区转移路径的移动储能系统时空转移矩阵;其次,考虑储能系统移动成本,根据混合整数二次规划方法构建第1阶段优化模型,以确定移动储能系统的多台区转移路径;然后,根据更小的时间颗粒度构建第2阶段优化模型管理移动储能系统的调度曲线。算例结果表明,移动储能系统可实现台区负载的优化运行,以及多台区间负荷特性的时空互补。 展开更多
关键词 低压配电台区 移动储能系统 时空转移矩阵 混合整数二次规划
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