Visual secret sharing has received more and more attention over the past years due to the fact that neither complex computation nor cryptographic knowledge is required to decrypt the secret image directly according to...Visual secret sharing has received more and more attention over the past years due to the fact that neither complex computation nor cryptographic knowledge is required to decrypt the secret image directly according to the characteristics of the human vision system. Considering the issue of sharing the secret image at multiple image resolutions with the meaningful shadows, in this paper, we present a friendly progressive visual secret sharing scheme without expanding the image size in the shadows and the reconstructed secret image based on applying a 2x2-sized block-wise operation to generate the shadows block by block. The proposed method can achieve these benefits： 1） the generated shadows are meaningful, and their sizes are not expanded, and 2） the secret image can be recovered at different resolutions by stacking different quantities of shadows together. The experimental results also show that the proposed method is superior to other compared schemes.展开更多
In order to apply the Human Visual System (HVS) model to JPEG2000 standard,several implementation alternatives are discussed and a new scheme of visual optimization isintroduced with modifying the slope of rate-distor...In order to apply the Human Visual System (HVS) model to JPEG2000 standard,several implementation alternatives are discussed and a new scheme of visual optimization isintroduced with modifying the slope of rate-distortion. The novelty is that the method of visual weighting is not lifting the coefficients in wavelet domain, but is complemented by code stream organization. It remains all the features of Embedded Block Coding with Optimized Truncation (EBCOT) such as resolution progressive, good robust for error bit spread and compatibility of lossless compression. Well performed than other methods, it keeps the shortest standard codestream and decompression time and owns the ability of VIsual Progressive (VIP) coding.展开更多
城市生态环境问题日益突出的现实使得城市生态系统健康研究备受关注。以1990-2023年Web of Science(WoS)和CNKI核心合集数据库为检索源,运用文献计量分析梳理当前有关城市生态系统健康的研究进展。结果表明:(1)国内外城市生态系统健康...城市生态环境问题日益突出的现实使得城市生态系统健康研究备受关注。以1990-2023年Web of Science(WoS)和CNKI核心合集数据库为检索源,运用文献计量分析梳理当前有关城市生态系统健康的研究进展。结果表明:(1)国内外城市生态系统健康研究总体可分为初始期、发展期和巩固期三个阶段,研究在2004年后呈现快速增长趋势。(2)中国学者是研究主力,但在该领域与其他国家机构的协同研究并不充分。(3)目前研究聚焦于确立城市生态系统健康的评估方法和评估体系,研究技术多元,但理论研究有待深入、评定标准难以准确量化以及城市生态系统健康管理有待系统性落实。因此,立足城市生态系统健康状况的时空演变规律,探究其与城市空间的耦合关系,继而构建国土空间规划语境下的调控管理方略框架将成为该领域研究的未来趋势。展开更多
Compared with the traditional crypto- graphy, visual cryptography （VC） decrypts secret images referring to the characteristics of human vision, rather than the cryptography knowledge or complex computations. Further...Compared with the traditional crypto- graphy, visual cryptography （VC） decrypts secret images referring to the characteristics of human vision, rather than the cryptography knowledge or complex computations. Furthermore, seeing to the freeness of the secret key, the whole process of encryption as well as deeryption for the visual cryptography meets a fast dealing course. As to the security concern, it is able to guarantee that no one can have access to any clues about the content of a secret image from individual cover images. Thus, owing to the studies on this area, the target of light-weighted cryptography is reached. Now the visual cryptography has been developed from the meaningless shadows to the meaningful ones. Seeing to the highly developed technique, some advanced VC techniques are introduced in this survey, respectively.展开更多
文章基于Web of Science核心数据库,利用CiteSpace 6.2.R2可视化软件,对与众包物流主题相关的129篇相关文献进行可视化科学计量分析,获得相关文献的发文量、作者图谱、机构图谱、国家图谱及关键词图谱,以探讨该领域的研究热点以及未来...文章基于Web of Science核心数据库,利用CiteSpace 6.2.R2可视化软件,对与众包物流主题相关的129篇相关文献进行可视化科学计量分析,获得相关文献的发文量、作者图谱、机构图谱、国家图谱及关键词图谱,以探讨该领域的研究热点以及未来发展趋势。研究结果表明,目前众包物流发文数量总体呈现出曲折上升的态势;作者以及机构的发文量相差不大且相对较少;最后一公里交付、车辆路线规划、众包运输定价策略以及算法优化等将是众包物流领域未来研究热点。展开更多
文摘Visual secret sharing has received more and more attention over the past years due to the fact that neither complex computation nor cryptographic knowledge is required to decrypt the secret image directly according to the characteristics of the human vision system. Considering the issue of sharing the secret image at multiple image resolutions with the meaningful shadows, in this paper, we present a friendly progressive visual secret sharing scheme without expanding the image size in the shadows and the reconstructed secret image based on applying a 2x2-sized block-wise operation to generate the shadows block by block. The proposed method can achieve these benefits： 1） the generated shadows are meaningful, and their sizes are not expanded, and 2） the secret image can be recovered at different resolutions by stacking different quantities of shadows together. The experimental results also show that the proposed method is superior to other compared schemes.
文摘In order to apply the Human Visual System (HVS) model to JPEG2000 standard,several implementation alternatives are discussed and a new scheme of visual optimization isintroduced with modifying the slope of rate-distortion. The novelty is that the method of visual weighting is not lifting the coefficients in wavelet domain, but is complemented by code stream organization. It remains all the features of Embedded Block Coding with Optimized Truncation (EBCOT) such as resolution progressive, good robust for error bit spread and compatibility of lossless compression. Well performed than other methods, it keeps the shortest standard codestream and decompression time and owns the ability of VIsual Progressive (VIP) coding.
文摘城市生态环境问题日益突出的现实使得城市生态系统健康研究备受关注。以1990-2023年Web of Science(WoS)和CNKI核心合集数据库为检索源,运用文献计量分析梳理当前有关城市生态系统健康的研究进展。结果表明:(1)国内外城市生态系统健康研究总体可分为初始期、发展期和巩固期三个阶段,研究在2004年后呈现快速增长趋势。(2)中国学者是研究主力,但在该领域与其他国家机构的协同研究并不充分。(3)目前研究聚焦于确立城市生态系统健康的评估方法和评估体系,研究技术多元,但理论研究有待深入、评定标准难以准确量化以及城市生态系统健康管理有待系统性落实。因此,立足城市生态系统健康状况的时空演变规律,探究其与城市空间的耦合关系,继而构建国土空间规划语境下的调控管理方略框架将成为该领域研究的未来趋势。
基金supported by National Science Council under Grant No. NSC98-2218-E-035-001-MY3
文摘Compared with the traditional crypto- graphy, visual cryptography （VC） decrypts secret images referring to the characteristics of human vision, rather than the cryptography knowledge or complex computations. Furthermore, seeing to the freeness of the secret key, the whole process of encryption as well as deeryption for the visual cryptography meets a fast dealing course. As to the security concern, it is able to guarantee that no one can have access to any clues about the content of a secret image from individual cover images. Thus, owing to the studies on this area, the target of light-weighted cryptography is reached. Now the visual cryptography has been developed from the meaningless shadows to the meaningful ones. Seeing to the highly developed technique, some advanced VC techniques are introduced in this survey, respectively.
文摘文章基于Web of Science核心数据库,利用CiteSpace 6.2.R2可视化软件,对与众包物流主题相关的129篇相关文献进行可视化科学计量分析,获得相关文献的发文量、作者图谱、机构图谱、国家图谱及关键词图谱,以探讨该领域的研究热点以及未来发展趋势。研究结果表明,目前众包物流发文数量总体呈现出曲折上升的态势;作者以及机构的发文量相差不大且相对较少;最后一公里交付、车辆路线规划、众包运输定价策略以及算法优化等将是众包物流领域未来研究热点。
