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Technique of Error Concealment for Block-Based Image Coding Using Genetic Algorithm
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作者 杨守义 罗伟雄 《Journal of Beijing Institute of Technology》 EI CAS 2002年第2期164-168,共5页
Since real world communication channels are not error free, the coded data transmitted on them may be corrupted, and block based image coding systems are vulnerable to transmission impairment. So the best neighborh... Since real world communication channels are not error free, the coded data transmitted on them may be corrupted, and block based image coding systems are vulnerable to transmission impairment. So the best neighborhood match method using genetic algorithm is used to conceal the error blocks. Experimental results show that the searching space can be greatly reduced by using genetic algorithm compared with exhaustive searching method, and good image quality is achieved. The peak signal noise ratios(PSNRs) of the restored images are increased greatly. 展开更多
关键词 block based image coding genetic algorithm error concealment
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BLOCK BASED NEWTON-LIKE BLENDING OSCULATORY RATIONAL INTERPOLATION 被引量:2
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作者 Shuo Tang Le Zou Chensheng Li 《Analysis in Theory and Applications》 2010年第3期201-214,共14页
With Newton's interpolating formula, we construct a kind of block based Newton-like blending osculatory interpolation.The interpolation provides us many flexible interpolation schemes for choices which include the ex... With Newton's interpolating formula, we construct a kind of block based Newton-like blending osculatory interpolation.The interpolation provides us many flexible interpolation schemes for choices which include the expansive Newton's polynomial inter- polation as its special case. A bivariate analogy is also discussed and numerical examples are given to show the effectiveness of the interpolation. 展开更多
关键词 Newton interpolation osculatory interpolation block based
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General Structures of Block Based Interpolational Function 被引量:1
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作者 Zou LE TANG SHUO 《Communications in Mathematical Research》 CSCD 2012年第3期193-208,共16页
We construct general structures of one and two variable interpolation function, without depending on the existence of divided difference or inverse differences, and we also discuss the block based osculatory interpola... We construct general structures of one and two variable interpolation function, without depending on the existence of divided difference or inverse differences, and we also discuss the block based osculatory interpolation in one variable case. Clearly, our method offers marly flexible interpolation schemes for choices. Error terms for the interpolation are determined and numerical examples are given to show the effectlveness of the results. 展开更多
关键词 osculatory interpolation continued fractions interpolation blendingrational interpolation block based interpolation
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Text extraction method for historical Tibetan document images based on block projections 被引量:3
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作者 段立娟 张西群 +1 位作者 马龙龙 吴健 《Optoelectronics Letters》 EI 2017年第6期457-461,共5页
Text extraction is an important initial step in digitizing the historical documents. In this paper, we present a text extraction method for historical Tibetan document images based on block projections. The task of te... Text extraction is an important initial step in digitizing the historical documents. In this paper, we present a text extraction method for historical Tibetan document images based on block projections. The task of text extraction is considered as text area detection and location problem. The images are divided equally into blocks and the blocks are filtered by the information of the categories of connected components and corner point density. By analyzing the filtered blocks' projections, the approximate text areas can be located, and the text regions are extracted. Experiments on the dataset of historical Tibetan documents demonstrate the effectiveness of the proposed method. 展开更多
关键词 HISTORICAL TIBETAN document filtered blockS bounding CORNER APPROXIMATE projection COORDINATE
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Polymerization of lactide and synthesis of block copolymer catalyzed by copper(Ⅱ) Schiff base complex 被引量:4
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作者 Anita Routaray Somanath Mantri +2 位作者 Nibedita Nath Alekha Kumar Sutar Tungabidya Maharana 《Chinese Chemical Letters》 SCIE CAS CSCD 2016年第12期1763-1766,共4页
In the present investigation, the novel copper Schiff base complex was synthesized and its catalytic activity was evaluated for the ring-opening polymerization (ROP) of lactide and block polymerization of poly(lact... In the present investigation, the novel copper Schiff base complex was synthesized and its catalytic activity was evaluated for the ring-opening polymerization (ROP) of lactide and block polymerization of poly(lactide) with po/y(ethylene glycol)methyl ether, 展开更多
关键词 ROP LACTIDE Schiff base Copper complex PLA block polymer
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Corundum Based Composite Block Containing Plastic Phase
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作者 Yu Lingyan 《China's Refractories》 CAS 2009年第3期29-31,共3页
1 Scope This standard specifies the definition, classification, technical requirements, test methods, inspection rules, packing, marking, transportation and quality certificate of corundum block containing plastic ph... 1 Scope This standard specifies the definition, classification, technical requirements, test methods, inspection rules, packing, marking, transportation and quality certificate of corundum block containing plastic phase. 展开更多
关键词 Corundum based Composite block Containing Plastic Phase than GB
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New Diamond Block Based Gradient Descent Search Algorithm for Motion Estimation in the MPEG- 4 Encoder
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作者 王振洲 李桂苓 《Transactions of Tianjin University》 EI CAS 2003年第3期202-205,共4页
Motion estimation is an important part of the MPEG- 4 encoder, due to its significant impact on the bit rate and the output quality of the encoder sequence. Unfortunately this feature takes a significant part of the e... Motion estimation is an important part of the MPEG- 4 encoder, due to its significant impact on the bit rate and the output quality of the encoder sequence. Unfortunately this feature takes a significant part of the encoding time especially when the straightforward full search(FS) algorithm is used. In this paper, a new algorithm named diamond block based gradient descent search (DBBGDS) algorithm, which is significantly faster than FS and gives similar quality of the output sequence, is proposed. At the same time, some other algorithms, such as three step search (TSS), improved three step search (ITSS), new three step search (NTSS), four step search (4SS), cellular search (CS) , diamond search (DS) and block based gradient descent search (BBGDS), are adopted and compared with DBBGDS. As the experimental results show, DBBGDS has its own advantages. Although DS has been adopted by the MPEG- 4 VM, its output sequence quality is worse than that of the proposed algorithm while its complexity is similar to the proposed one. Compared with BBGDS, the proposed algorithm can achieve a better output quality. 展开更多
关键词 MPEG motion estimation full search(FS) block based gradient descent search(BBGDS) diamond search(DS) new three step search(NTSS)
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Steganalysis of MSU Stego Video Based on Block Matching of Interframe Collusion and Motion Detection
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作者 REN Yanzhen WANG Mingjie +2 位作者 ZHAO Yanbin WANG Lina CAI Tingting 《Wuhan University Journal of Natural Sciences》 CAS 2012年第5期441-446,共6页
MSU Stego Video is a public video steganographic tool, which has strong robustness and is regarded as a real video steganographic tool. In order to increase the detection rate, this paper proposes a new steganoalysis ... MSU Stego Video is a public video steganographic tool, which has strong robustness and is regarded as a real video steganographic tool. In order to increase the detection rate, this paper proposes a new steganoalysis method against MSU, which uses the chessboard character of MSU embedded video, proposes a down-sample block-based collusion method to estimate the original frame and checks the chessboard mode of the different frame between tested frame and estimated frame to detect MSU steganographic evidences. To reduce the error introduced by severe movement of the video content, a method that abandons severe motion blocks from detecting is proposed. The experiment results show that the false negative rate of the proposed algorithm is lower than 5%, and the false positive rate is lower than 2%. Our algorithm has significantly better performance than existing algorithms. Especially to the video that has fast motion, the algorithm has more remarkable performance. 展开更多
关键词 MSU Stego Video video steganalysis block-based matching chessboard pattern motion detection
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Block Based Bivariate Blending Rational Interpolation via Symmetric Branched Continued Fractions
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作者 Qianjin Zhao Jieqing Tan 《Numerical Mathematics A Journal of Chinese Universities(English Series)》 SCIE 2007年第1期63-73,共11页
This paper constructs a new kind of block based bivariate blending rational interpolation via symmetric branched continued fractions. The construction process may be outlined as follows. The first step is to divide th... This paper constructs a new kind of block based bivariate blending rational interpolation via symmetric branched continued fractions. The construction process may be outlined as follows. The first step is to divide the original set of support points into some subsets (blocks). Then construct each block by using symmetric branched continued fraction. Finally assemble these blocks by Newton’s method to shape the whole interpolation scheme. Our new method offers many flexible bivariate blending rational interpolation schemes which include the classical bivariate Newton’s polynomial interpolation and symmetric branched continued fraction interpolation as its special cases. The block based bivariate blending rational interpolation is in fact a kind of tradeoff between the purely linear interpolation and the purely nonlinear interpolation. Finally, numerical examples are given to show the effectiveness of the proposed method. 展开更多
关键词 插值 函数构造论 二变量 非线性特征
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Twin-block矫治器矫治青少年安氏Ⅱ类1分类错疗效的系统评价 被引量:13
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作者 龙飞 栗震亚 +2 位作者 杨克虎 马彬 任卫萍 《实用口腔医学杂志》 CAS CSCD 北大核心 2009年第6期880-884,共5页
目的:评价Twin-block矫治器治疗青少年安氏II类1分类错畸形的有效性。方法:计算机检索PubMed(1966~2008.9)、Cochrane library(2008年第3期)、Embase(1984~2008.9.);中国生物医学文献数据库(CBM)(1978~2008.9)、中国期刊全文数据库... 目的:评价Twin-block矫治器治疗青少年安氏II类1分类错畸形的有效性。方法:计算机检索PubMed(1966~2008.9)、Cochrane library(2008年第3期)、Embase(1984~2008.9.);中国生物医学文献数据库(CBM)(1978~2008.9)、中国期刊全文数据库(CNKI)(1994~2008.9)、中文科技期刊数据库(VIP)(1994~2008.9)。手工检索中华口腔医学杂志(1994~2008)等5种中文期刊。纳入Twin-block矫治器治疗青少年安氏II类1分类错畸形的随机对照试验(RCT)。纳入研究按照Cochrane Reviewer's Handbook 4.2.6随机对照试验的质量标准评价。统计分析采用RevMan5.0.0版软件。结果:共纳入4个RCT,289例受试者。Meta分析显示和对照组相比,治疗组患者的覆、覆盖、ANB角、Ls-E有明显减小;SNB、Ar-Gn、鼻唇角、颏唇角有明显增大,差异在2组之间有统计学意义,但在SNA、Li-E变化方面,尚无差别。结论:Twin-block矫治器治疗青少年安氏II类1分类错畸形,能明显减小覆盖、覆,促进下颌生长,而对上颌发育的抑制作用不明显。尚需要更多高质量、大样本的RCT进一步验证Twin-block矫治器的疗效。 展开更多
关键词 TWIN-block矫治器 错畸形 循证医学 系统评价
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轻量级分组密码Lblock算法的Nibble积分攻击 被引量:1
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作者 王衡 张文英 韩国勇 《小型微型计算机系统》 CSCD 北大核心 2017年第8期1704-1707,共4页
Lblock算法是2011年提出的一种轻量级分组密码密码算法,在有限的环境下得到广泛使用.积分攻击是一种有效的密码分析方法,对于Lblock算法的基于比特的积分攻击,可以先构建8轮区分器,再向前做4轮高阶积分扩散,然后在积分区分器后加上5轮... Lblock算法是2011年提出的一种轻量级分组密码密码算法,在有限的环境下得到广泛使用.积分攻击是一种有效的密码分析方法,对于Lblock算法的基于比特的积分攻击,可以先构建8轮区分器,再向前做4轮高阶积分扩散,然后在积分区分器后加上5轮做17轮积分攻击,但是攻击轮数较少,且攻击复杂度较高,本文是在基于字节的积分攻击也是首先构建8轮区分器,再向前做6轮高阶积分扩散,构造14轮区分器,在积分区分器后面加7轮,猜测部分密钥,对其进行解密,做21轮积分攻击,时间复杂度降低.然后结合不同的对Lblock算法的攻击方法,对其进行比较,积分攻击在尽可能多的轮数下,时间复杂度降低. 展开更多
关键词 Lblock 积分攻击 积分区分器 基于字节的攻击 轻量级分组密码
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Comparison between the seismic response of 2D and 3D models of rigid blocks 被引量:3
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作者 Angelo Di Egidio Daniele Zulli Alessandro Contento 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2014年第1期151-162,共12页
A three-dimensional rigid body on the shape of a parallelepiped is modelled in order to rock on a side or a vertex of the base,in order to evaluate the seismic response of rigid blocks lying on a horizontal support.Th... A three-dimensional rigid body on the shape of a parallelepiped is modelled in order to rock on a side or a vertex of the base,in order to evaluate the seismic response of rigid blocks lying on a horizontal support.The center of mass of the body is considered as eccentric with respect to its geometric center.As seismic input,three Italian recorded accelerograms,with different spectral content,are used.The study is mainly conducted to highlight the differences between the seismic response of 2D and 3D models of rigid blocks,with the aim to understand if,in some cases,the use of the 3D model of rigid block is required to obtain safer results.In fact,the outcomes show that in some ranges of the geometrical and mechanical parameters that characterize the excitation and the body,a two-dimensional model,which is not able to consider the 3D rocking on a vertex,can provide unsafe results.In particular,it is found that the overturning process of the three-dimensional block can occur under excitations which are lower than those which overturn a corresponding two-dimensional block. 展开更多
关键词 seismic excitation 3D rigid block rectangular base ROCKING OVERTURNING
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The advantage of blue InGaN multiple quantum wells light-emitting diodes with p-AlInN electron blocking layer 被引量:4
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作者 卢太平 李述体 +8 位作者 张康 刘超 肖国伟 周玉刚 郑树文 尹以安 仵乐娟 王海龙 杨孝东 《Chinese Physics B》 SCIE EI CAS CSCD 2011年第9期456-459,共4页
InGaN based light-emitting diodes (LEDs) with different electron blocking layers have been numerically investi- gated using the APSYS simulation software. It is found that the structure with a p-AlInN electron block... InGaN based light-emitting diodes (LEDs) with different electron blocking layers have been numerically investi- gated using the APSYS simulation software. It is found that the structure with a p-AlInN electron blocking layer showes improved light output power, lower current leakage, and smaller efficiency droop. Based on numerical simulation and analysis, these improvements of the electrical and optical characteristics are mainly attributed to the efficient electron blocking in the InGaN/GaN multiple quantum wells (MQWs). 展开更多
关键词 GaN-based light-emitting diodes electron blocking layer AIInN
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One-step preparation of polyimide-inlaid amine-rich porous organic block copolymer for efficient removal of chlorophenols from aqueous solution 被引量:1
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作者 Yanyang Liu Haijian Ou +4 位作者 Shangqing Li Qingliang You Huixian Liu Guiying Liao Dongsheng Wang 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2019年第4期215-229,共15页
A novel polyimide-inlaid amine-rich porous organic block copolymer(PI-b-ARPOP) was prepared via one-step polymerization by using different molar ratios of melamine(MA)/terephthalaldehyde(TA)/pyromellitic dianhydride(P... A novel polyimide-inlaid amine-rich porous organic block copolymer(PI-b-ARPOP) was prepared via one-step polymerization by using different molar ratios of melamine(MA)/terephthalaldehyde(TA)/pyromellitic dianhydride(PMDA), at molar ratios of 4/3/1, 4/2/2 and 4/1/3. The copolymer contained both aminal groups belonging to ARPOP and imide groups belonging to PI, and the bonding styles of the monomers and growth orientations of the polymeric chains were diversiform, forming an excellent porous structure. Notably, MA/TA/PMDA(4/2/2) had a surface area and pore volume of 487.27 m^2/g and 1.169 cm^3/g,respectively. The adsorption performance of the materials towards 2,4-dichlorophenol(2,4-DCP) in ultra-pure water was systematically studied. The pH value of 7 was optimal in aqueous solution. Na^+ and Cl^-ions did not negatively affect the adsorption process, while humic acid(HA) slightly decreased the capacity. The equilibrium time was 40 sec, and the maximum adsorption capacity reached 282.49 mg/g at 298 K. The removal process was endothermic and spontaneous, and the copolymer could maintain its porous structure and consistent performance after regeneration by treatment with alkali. Moreover, to further assess the practical applicability of the material, the adsorption performance towards 2,4-DCP in river water was also investigated. This paper demonstrated that the PI-b-ARPOP can be an efficient and practical adsorbent to remove chlorophenols from aqueous solution. 展开更多
关键词 POROUS block copolymer SCHIFF base POLYIMIDE Adsorption 2 4-DICHLOROPHENOL
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LBlock算法的基于比特积分攻击 被引量:1
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作者 潘志舒 郭建胜 《信息工程大学学报》 2013年第1期30-35,共6页
对分组密码算法LBlock在基于比特积分攻击下的安全性进行了分析,利用基于比特的积分攻击思想,构造了8轮积分区分器,并向前扩展到12轮,基于该区分器对17轮算法进行了积分攻击,给出了攻击算法,攻击的计算复杂度约为263.7。
关键词 分组密码 密码分析 基于比特积分攻击 Lblock算法
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OPTIMIZATION AND METHOD OF DRAWING CONTROL IN BLOCK CAVING AT TONGKUANGYU MINE
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作者 Zhou, Aimin 《中国有色金属学会会刊:英文版》 EI CSCD 1997年第2期10-15,共6页
OPTIMIZATIONANDMETHODOFDRAWINGCONTROLINBLOCKCAVINGATTONGKUANGYUMINE①ZhouAiminChangshaInstituteofMiningResear... OPTIMIZATIONANDMETHODOFDRAWINGCONTROLINBLOCKCAVINGATTONGKUANGYUMINE①ZhouAiminChangshaInstituteofMiningResearch,Changsha410012... 展开更多
关键词 block CAVING METHOD DRAWING CONTROL computer based production planning DRAWING OPTIMIZATION
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天基智能模型的协同可信分布式推理技术
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作者 杨德伟 栗渊钧 +1 位作者 聂勇仕 冯笑 《北京理工大学学报》 北大核心 2025年第6期629-640,共12页
针对天基网络中多节点分布式推理及推理过程中的安全隐私挑战,研究协同可信的天基智能模型分布式推理技术.构建基于区块链的天基智能模型推理系统——包含云端节点和边缘卫星节点集群,提出协同可信的天基智能模型分布式推理方法,准备阶... 针对天基网络中多节点分布式推理及推理过程中的安全隐私挑战,研究协同可信的天基智能模型分布式推理技术.构建基于区块链的天基智能模型推理系统——包含云端节点和边缘卫星节点集群,提出协同可信的天基智能模型分布式推理方法,准备阶段基于负载均衡和时延最小对模型进行自适应分割,推理阶段采用区块链技术实现协同可信的集群推理.实验结果表明,所设计的系统及方法能够保障分布式节点安全有效地完成智能模型分布式推理,为智能模型在卫星场景中的应用提供支撑. 展开更多
关键词 天基网络 分布式推理 区块链
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油基高密度钻井液污染解堵液体系
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作者 罗志锋 李轲 闫丙森 《钻井液与完井液》 北大核心 2025年第3期418-424,共7页
油基高密度钻井液因其高度的稳定性和抑制性,在钻井过程中有着广泛的应用,但因其经过滤失、迁移后所形成的重晶石滤饼对储层有着很大的危害,导致油气产量下降。常规化学方法如酸溶,碱溶等方式难以解除滤饼造成的污染。以螯合剂DTPA为主... 油基高密度钻井液因其高度的稳定性和抑制性,在钻井过程中有着广泛的应用,但因其经过滤失、迁移后所形成的重晶石滤饼对储层有着很大的危害,导致油气产量下降。常规化学方法如酸溶,碱溶等方式难以解除滤饼造成的污染。以螯合剂DTPA为主体,添加碳酸钾为转化剂、草酸为催化剂、过硫酸铵为氧化剂,结合以AEC为表面活性剂和乙二醇丁醚为有机溶剂,形成了一套稳定、高效的油基高密度解堵液体系,其对钻井液滤饼渗透、螯合、增溶及洗涤作用,能破坏油基钻井液滤饼内部结构,降低物质间的胶黏作用,增加对油基高密度钻井液污染的解除。高密度钻井液固相螯合液配方为:20%DTPA+3%草酸+6%K_(2)CO_(3)+0.06%过硫酸铵+KOH,油相清洗液的最终配方为:12%乙二醇丁醚+0.5%AEC,对该体系解堵能力,油相清洗能力进行评价。结果表明,在不同的温度条件下(120℃~180℃),复合解堵体系均能对高密度钻井液滤饼有效降解,120℃下单级处理4 h达到66.7%的滤饼溶解率,在120℃多级处理4 h对滤饼的溶解率为72.22%,且滤饼溶解率随温度上升也同时增加,180℃多级处理8 h后溶解率为89.24%,最高腐蚀速率为1.1537g/(m^(2)·h),其具有优秀的解堵性能和耐温性能,在同等实验条件下,复合解堵方法较常规螯合解堵方法对油基钻井液滤饼的溶解效率提升了20%左右,经现场试验证明,该体系能有效解决高密度钻井液所造成的污染及堵塞,其产能恢复率为90%左右。 展开更多
关键词 油基高密度钻井液 解堵液体系 油相清洗能力 重晶石滤饼 油相
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理想格下的紧凑身份加密方案
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作者 赵宗渠 张帆 汤永利 《重庆邮电大学学报(自然科学版)》 北大核心 2025年第6期954-964,共11页
格上基于身份加密技术(identity-based encryption,IBE)能够抵抗量子计算,并将个体的身份信息直接转化为公钥,简化了公钥基础设施(public key infrastructure,PKI)对大规模用户群体中的公钥管理。在资源受限的物联网环境中,IBE加密方案... 格上基于身份加密技术(identity-based encryption,IBE)能够抵抗量子计算,并将个体的身份信息直接转化为公钥,简化了公钥基础设施(public key infrastructure,PKI)对大规模用户群体中的公钥管理。在资源受限的物联网环境中,IBE加密方案密文较大造成存储和传输的成本较高,计算效率较低使得运算速度不能满足实时数据传输需求。针对上述问题,提出了一种基于身份加密选择明文攻击下的不可区分性(IND-ID-CPA)安全的IBE低膨胀率方案。该方案基于环上容错学习(ring learning with errors,R-LWE)问题,提出分块复用技术,重复使用辅助解密向量b,实现对多个明文的同时加密;运用Kyber压缩技术,减小了密文大小;引入明文扩张参数,使多项式能包含更多比特信息。分析结果表明,提出的方案在不同的安全等级下,具有更好的加解密效率,有效降低了密文膨胀率。 展开更多
关键词 基于身份加密 环上容错学习 分块复用技术 压缩技术 明文扩张参数
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肺泡灌洗液细胞蜡块在诊断肺泡蛋白沉积症中的应用
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作者 刘甜 何惠华 +2 位作者 阎红琳 成红豆 袁静萍 《临床与实验病理学杂志》 北大核心 2025年第3期397-399,共3页
目的探讨肺泡灌洗液制作细胞蜡块在诊断肺泡蛋白沉积症(pulmonary alveolar proteinosis,PAP)中的应用。方法收集15例PAP的临床资料,比较细胞学涂片、液基薄层细胞学、细胞蜡块在诊断PAP中的优劣。结果细胞学涂片难以分辨蛋白沉积物;液... 目的探讨肺泡灌洗液制作细胞蜡块在诊断肺泡蛋白沉积症(pulmonary alveolar proteinosis,PAP)中的应用。方法收集15例PAP的临床资料,比较细胞学涂片、液基薄层细胞学、细胞蜡块在诊断PAP中的优劣。结果细胞学涂片难以分辨蛋白沉积物;液基薄层细胞学检测虽然保留大量有诊断意义的细胞,但可能会丢掉大量蛋白沉积物质,且不能重复切片,无法进行多次特殊染色;细胞蜡块可最大限度保留细胞量,同时可连续切片结合特殊染色做出明确诊断。结论肺泡灌洗液细胞蜡块法能提高制片中的细胞量、阳性检出率,同时结合特殊染色,对PAP诊断具有更好的应用价值。 展开更多
关键词 细胞蜡块 肺泡灌洗液 细胞学涂片 液基薄层细胞学
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