期刊文献+
共找到1,639篇文章
< 1 2 82 >
每页显示 20 50 100
A New Eighth Order Implicit Block Algorithms for the Direct Solution of Second Order Ordinary Differential Equations
1
作者 Ademola M. Badmus 《American Journal of Computational Mathematics》 2014年第4期376-386,共11页
This paper focuses on derivation of a uniform order 8 implicit block method for the direct solution of general second order differential equations through continuous coefficients of Linear Multi-step Method (LMM). The... This paper focuses on derivation of a uniform order 8 implicit block method for the direct solution of general second order differential equations through continuous coefficients of Linear Multi-step Method (LMM). The continuous formulation and its first derivatives were evaluated at some selected grid and off grid points to obtain our proposed method. The superiority of the method over the existing methods is established numerically. 展开更多
关键词 UNIFORM Order SECOND Order INITIAL Value Problem IMPLICIT block algorithms Zero Stable
在线阅读 下载PDF
A hybrid genetic-simulated annealing algorithm for optimization of hydraulic manifold blocks 被引量:7
2
作者 刘万辉 田树军 +1 位作者 贾春强 曹宇宁 《Journal of Shanghai University(English Edition)》 CAS 2008年第3期261-267,共7页
This paper establishes a mathematical model of multi-objective optimization with behavior constraints in solid space based on the problem of optimal design of hydraulic manifold blocks (HMB). Due to the limitation o... This paper establishes a mathematical model of multi-objective optimization with behavior constraints in solid space based on the problem of optimal design of hydraulic manifold blocks (HMB). Due to the limitation of its local search ability of genetic algorithm (GA) in solving a massive combinatorial optimization problem, simulated annealing (SA) is combined, the multi-parameter concatenated coding is adopted, and the memory function is added. Thus a hybrid genetic-simulated annealing with memory function is formed. Examples show that the modified algorithm can improve the local search ability in the solution space, and the solution quality. 展开更多
关键词 hydraulic manifold blocks (HMB) genetic algorithm (GA) simulated annealing (SA) optimal design
在线阅读 下载PDF
A Linear-Time Algorithm for 2-Step Domination in Block Graphs
3
作者 Yancai ZHAO Lianying MIAO Zuhua LIAO 《Journal of Mathematical Research with Applications》 CSCD 2015年第3期285-290,共6页
The 2-step domination problem is to find a minimum vertex set D of a graph such that every vertex of the graph is either in D or at distance two from some vertex of D. In the present paper, by using a labeling method,... The 2-step domination problem is to find a minimum vertex set D of a graph such that every vertex of the graph is either in D or at distance two from some vertex of D. In the present paper, by using a labeling method, we provide an O(m) time algorithm to solve the 2-step domination problem on block graphs, a superclass of trees. 展开更多
关键词 2-step domination block graph algorithm labeling method
原文传递
Some Results for Exact Support Recovery of Block Joint Sparse Matrix via Block Multiple Measurement Vectors Algorithm
4
作者 Yingna Pan Pingping Zhang 《Journal of Applied Mathematics and Physics》 2023年第4期1098-1112,共15页
Block multiple measurement vectors (BMMV) is a reconstruction algorithm that can be used to recover the support of block K-joint sparse matrix X from Y = ΨX + V. In this paper, we propose a sufficient condition for a... Block multiple measurement vectors (BMMV) is a reconstruction algorithm that can be used to recover the support of block K-joint sparse matrix X from Y = ΨX + V. In this paper, we propose a sufficient condition for accurate support recovery of the block K-joint sparse matrix via the BMMV algorithm in the noisy case. Furthermore, we show the optimality of the condition we proposed in the absence of noise when the problem reduces to single measurement vector case. 展开更多
关键词 Support Recovery Compressed Sensing block Multiple Measurement Vectors algorithm block Restricted Isometry Property
在线阅读 下载PDF
BLOCK ADAPTIVE RECURSIVE ALGORITHM FOR VIDEO CONFERENCE CODING
5
作者 Tu Guofang(Graduate School, University of Science and Technology of China, Beijing 100039)Zhang Can(704 Institute, Company of Aero-Space Industry, Beijing 100076) 《Journal of Electronics(China)》 1996年第2期140-146,共7页
This paper presents a new motion estimation algorithm for video conference signal coding. This type of algorithm is called block adaptive recursive algorithm (BARA). Simulation results show that this new algorithm has... This paper presents a new motion estimation algorithm for video conference signal coding. This type of algorithm is called block adaptive recursive algorithm (BARA). Simulation results show that this new algorithm has better performance than conventional ones. 展开更多
关键词 MOTION estimation block ADAPTIVE RECURSIVE algorithm MOTION compensated IMAGE CODING
在线阅读 下载PDF
Hardware Architecture Design of Block-Matching and 3D-Filtering Denoising Algorithm
6
作者 张昊 刘文江 +2 位作者 王若琳 刘涛 戎蒙恬 《Journal of Shanghai Jiaotong university(Science)》 EI 2016年第2期173-183,共11页
Block-matching and 3D-filtering(BM3D) is a state of the art denoising algorithm for image/video,which takes full advantages of the spatial correlation and the temporal correlation of the video. The algorithm performan... Block-matching and 3D-filtering(BM3D) is a state of the art denoising algorithm for image/video,which takes full advantages of the spatial correlation and the temporal correlation of the video. The algorithm performance comes at the price of more similar blocks finding and filtering which bring high computation and memory access. Area, memory bandwidth and computation are the major bottlenecks to design a feasible architecture because of large frame size and search range. In this paper, we introduce a novel structure to increase data reuse rate and reduce the internal static-random-access-memory(SRAM) memory. Our target is to design a phase alternating line(PAL) or real-time processing chip of BM3 D. We propose an application specific integrated circuit(ASIC) architecture of BM3 D for a 720 × 576 BT656 PAL format. The feature of the chip is with 100 MHz system frequency and a 166-MHz 32-bit double data rate(DDR). When noise is σ = 25, we successfully realize real-time denoising and achieve about 10 d B peak signal to noise ratio(PSNR) advance just by one iteration of the BM3 D algorithm. 展开更多
关键词 block-matching and 3D-filtering(BM3D) denoising algorithm IMPLEMENTATION block-MATCHING 3D-filtering AGGREGATION
原文传递
Adaptive block greedy algorithms for receiving multi-narrowband signal in compressive sensing radar reconnaissance receiver
7
作者 ZHANG Chaozhu XU Hongyi JIANG Haiqing 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2018年第6期1158-1169,共12页
This paper extends the application of compressive sensing(CS) to the radar reconnaissance receiver for receiving the multi-narrowband signal. By combining the concept of the block sparsity, the self-adaption methods, ... This paper extends the application of compressive sensing(CS) to the radar reconnaissance receiver for receiving the multi-narrowband signal. By combining the concept of the block sparsity, the self-adaption methods, the binary tree search,and the residual monitoring mechanism, two adaptive block greedy algorithms are proposed to achieve a high probability adaptive reconstruction. The use of the block sparsity can greatly improve the efficiency of the support selection and reduce the lower boundary of the sub-sampling rate. Furthermore, the addition of binary tree search and monitoring mechanism with two different supports self-adaption methods overcome the instability caused by the fixed block length while optimizing the recovery of the unknown signal.The simulations and analysis of the adaptive reconstruction ability and theoretical computational complexity are given. Also, we verify the feasibility and effectiveness of the two algorithms by the experiments of receiving multi-narrowband signals on an analogto-information converter(AIC). Finally, an optimum reconstruction characteristic of two algorithms is found to facilitate efficient reception in practical applications. 展开更多
关键词 compressive sensing(CS) adaptive greedy algorithm block sparsity analog-to-information convertor(AIC) multinarrowband signal
在线阅读 下载PDF
FBS-uBlock:灵活的uBlock算法比特切片优化方法
8
作者 龚子睿 郭华 +3 位作者 陈晨 张宇轩 陈俊鑫 关振宇 《软件学报》 北大核心 2025年第10期4827-4845,共19页
uBlock算法在算法设计、侧信道防护、物联网应用、密码分析领域得到了广泛应用.虽然uBlock算法适合高速实现,但目前该算法公开的实现速率远不如AES、SM4等算法.比特切片是优化分组密码的常用方法,但在采用比特切片优化uBlock算法时,面... uBlock算法在算法设计、侧信道防护、物联网应用、密码分析领域得到了广泛应用.虽然uBlock算法适合高速实现,但目前该算法公开的实现速率远不如AES、SM4等算法.比特切片是优化分组密码的常用方法,但在采用比特切片优化uBlock算法时,面临着因寄存器资源不足而导致的巨大访存开销问题.为uBlock算法设计了一种灵活的比特切片优化方法FBS-uBlock(flexible bit slicing uBlock),降低算法在比特切片下占用的寄存器数量,进而降低访存开销,提升速率.经过测试,该优化方法最多能够让uBlock-128/128、uBlock-128/256和uBlock-256/256算法的访存指令分别降低71%、71%和72%,加密速率最高能够分别达到12758 Mb/s、8944 Mb/s和8984 Mb/s,比设计文档中的实现速率分别提升了3.9、4.2和3.4倍. 展开更多
关键词 分组密码 ublock算法 软件优化 比特切片 单指令多数据
在线阅读 下载PDF
Analysis and Design for Unsymmetrical Block Encryption Algorithm
9
作者 王以刚 孔令飞 《Journal of China Textile University(English Edition)》 EI CAS 1999年第2期50-52,共3页
This article explains the imbalance in DES and introduces the operators in IDEA. At last it puts forward a Unsym-metrical Block Encryption Algorithm which is achieved by adding some operators to DES.
关键词 BLACK CIPHER CIPHER algorithm DES IDEA UNSYMMETRICAL block ENCRYPTION
在线阅读 下载PDF
An Efficient Algorithm for Self-consistent Field Theory Calculations of Complex Self-assembled Structures of Block Copolymer Melts
10
作者 Jun-Qing Song Yi-Xin Liu Hong-Dong Zhang 《Chinese Journal of Polymer Science》 SCIE CAS CSCD 2018年第4期488-496,共9页
Self-consistent field theory(SCFT), as a state-of-the-art technique for studying the self-assembly of block copolymers, is attracting continuous efforts to improve its accuracy and efficiency. Here we present a four... Self-consistent field theory(SCFT), as a state-of-the-art technique for studying the self-assembly of block copolymers, is attracting continuous efforts to improve its accuracy and efficiency. Here we present a fourth-order exponential time differencing Runge-Kutta algorithm(ETDRK4) to solve the modified diffusion equation(MDE) which is the most time-consuming part of a SCFT calculation. By making a careful comparison with currently most efficient and popular algorithms, we demonstrate that the ETDRK4 algorithm significantly reduces the number of chain contour steps in solving the MDE, resulting in a boost of the overall computation efficiency, while it shares the same spatial accuracy with other algorithms. In addition, to demonstrate the power of our ETDRK4 algorithm, we apply it to compute the phase boundaries of the bicontinuous gyroid phase in the strong segregation regime and to verify the existence of the triple point of the O70 phase, the lamellar phase and the cylindrical phase. 展开更多
关键词 block copolymer Self-consistent field theory algorithm Pseudo-spectral Phase structure
原文传递
An Electronic Image Stabilization Algorithm Based on Efficient Block Matching on the Bitplane
11
作者 Luo Fang Qin Xiaozhen 《Open Journal of Applied Sciences》 2013年第1期1-5,共5页
This paper proposes an electronic image stabilization algorithm based on efficient block matching on the plane. This algorithm uses a hexagonal search algorithm, and uses the bit-planes to estimate and compensate for ... This paper proposes an electronic image stabilization algorithm based on efficient block matching on the plane. This algorithm uses a hexagonal search algorithm, and uses the bit-planes to estimate and compensate for the translational motion between video sequences at the same time;As for the rotary motion vector generated in the video sequences, in order to highlight the intensity change of the image sequence, the algorithm firstly conducts Laplace transform for the reference frame, then select a number of characteristics at the image edge to make block matching with the current frame, calculate and compensate for the rotational movement that may exist finally. Through theoretical analysis and simula-tion, we prove that, as for a mixed translational and rotational motion video sequences, the proposed algorithm can reduce required time for block matching computation ,while improving the accuracy of the electronic image stabilization. 展开更多
关键词 Electronic Image STABILIZATION algorithm BIT PLANE block MATCHING HEXAGON Motion Estimation
在线阅读 下载PDF
Solving Job-Shop Scheduling Problems by Genetic Algorithms Based on Building Block Hypothesis
12
作者 CHENG Rong CHEN You-ping LI Zhi-gang 《International Journal of Plant Engineering and Management》 2006年第2期119-123,共5页
In this paper, we propose a new genetic algorithm for job-shop scheduling problems (JSP). The proposed method uses the operation-based representation, based on schema theorem and building block hypothesis, a new cro... In this paper, we propose a new genetic algorithm for job-shop scheduling problems (JSP). The proposed method uses the operation-based representation, based on schema theorem and building block hypothesis, a new crossover is proposed : By selecting short, low order highly fit schemas to genetic operator, the crossover can exchange meaningful ordering information of parents effectively and can search the global optimization. Simulation results on MT benchmark problem coded by C + + show that our genetic operators are very powerful and suitable to job-shop scheduling problems and our method outperforms the previous GA-based approaches. 展开更多
关键词 job-shop scheduling genetic algorithm schema theorem building block hypothesis
在线阅读 下载PDF
A Novel Decoder Based on Parallel Genetic Algorithms for Linear Block Codes
13
作者 Abdeslam Ahmadi Faissal El Bouanani +1 位作者 Hussain Ben-Azza Youssef Benghabrit 《International Journal of Communications, Network and System Sciences》 2013年第1期66-76,共11页
Genetic algorithms offer very good performances for solving large optimization problems, especially in the domain of error-correcting codes. However, they have a major drawback related to the time complexity and memor... Genetic algorithms offer very good performances for solving large optimization problems, especially in the domain of error-correcting codes. However, they have a major drawback related to the time complexity and memory occupation when running on a uniprocessor computer. This paper proposes a parallel decoder for linear block codes, using parallel genetic algorithms (PGA). The good performance and time complexity are confirmed by theoretical study and by simulations on BCH(63,30,14) codes over both AWGN and flat Rayleigh fading channels. The simulation results show that the coding gain between parallel and single genetic algorithm is about 0.7 dB at BER = 10﹣5 with only 4 processors. 展开更多
关键词 CHANNEL Coding Linear block Codes META-HEURISTICS PARALLEL Genetic algorithmS PARALLEL Decoding algorithmS Time Complexity Flat FADING CHANNEL AWGN
在线阅读 下载PDF
分数阶微分方程block-by-block算法的最优阶收敛性分析 被引量:2
14
作者 王自强 曹俊英 《工程数学学报》 CSCD 北大核心 2015年第4期533-545,共13页
经典的block-by-block方法是求解积分方程的一种高效的数值方法.研究者们已经把经典的block-by-block方法成功地用在构造非线性分数阶常微分方程的高阶数值格式上,对该格式的收敛性分析也已经有了初步的结果.但数值实验的结果表明目前... 经典的block-by-block方法是求解积分方程的一种高效的数值方法.研究者们已经把经典的block-by-block方法成功地用在构造非线性分数阶常微分方程的高阶数值格式上,对该格式的收敛性分析也已经有了初步的结果.但数值实验的结果表明目前的理论分析仍未达到最优阶误差估计.本文将利用Taylor公式和积分中值定理对非线性分数阶常微分方程的block-by-block方法的收敛性进行细致的分析,对其获得了最优阶误差估计,最后通过数值算例验证了理论分析的正确性. 展开更多
关键词 分数阶微分方程 block-by-block算法 收敛性分析 Caputo导数
在线阅读 下载PDF
对轻量级分组密码算法LBlock的差分故障攻击 被引量:3
15
作者 王涛 王永娟 +1 位作者 高杨 张诗怡 《密码学报》 CSCD 2019年第1期18-26,共9页
本文首先分析差分故障攻击的故障模型与原理,利用S盒的差分不均匀性,通过建立输入差分、输出差分和可能输入值之间的对应关系,给出差分故障分析的优化方案,实现快速归约,提高差分故障攻击的效率.本文通过对LBlock算法建立对应关系,可以... 本文首先分析差分故障攻击的故障模型与原理,利用S盒的差分不均匀性,通过建立输入差分、输出差分和可能输入值之间的对应关系,给出差分故障分析的优化方案,实现快速归约,提高差分故障攻击的效率.本文通过对LBlock算法建立对应关系,可以快速直观缩小输入值取值空间,进而快速确定对应扩展密钥.对于不同故障值(输入差分),对应的输出差分和可能输入值均不相同,可以得到二元关系集合.由于轻量级分组密码S盒多为4×4 S盒,该集合中元素较少,注入少量不同故障值,通过查表,对可能输入值取交集即可快速确定唯一可能输入值.将优化方案应用于LBlock轻量级分组密码算法,在最后一轮输入处注入2次宽度为16 bit的故障可恢复最后一轮轮密钥,然后将状态回推一轮,在倒数第二轮输入处注入2次宽度为16 bit的故障可恢复倒数第二轮密钥.根据密钥扩展方案,恢复两轮轮密钥后将恢复主密钥的计算复杂度降为2^(19). 展开更多
关键词 轻量级分组密码 Lblock算法 差分故障攻击
在线阅读 下载PDF
基于分块策略的二维装箱问题求解
16
作者 赵向领 苏坛杰 +2 位作者 秦雪 李朝阳 陈晓刚 《包装工程》 北大核心 2026年第1期111-121,共11页
目的提升条带型容器二维装箱问题的空间利用率和算法效率,支持物流、制造等复杂装载场景下的资源优化。方法提出基于分块和分层叠加的两阶段优化算法。第1阶段为分块策略,以最小分块数量和最大所有分块长度之和为目标,依据条带型容器长... 目的提升条带型容器二维装箱问题的空间利用率和算法效率,支持物流、制造等复杂装载场景下的资源优化。方法提出基于分块和分层叠加的两阶段优化算法。第1阶段为分块策略,以最小分块数量和最大所有分块长度之和为目标,依据条带型容器长度,把容器分割成多块,并关联每块与某一待装物品的长度。第2阶段为单块组装策略,引入动态分层叠加机制,建立单块组装算法。结果采用17组经典Benchmark数据,与自适应分块策略、Gurobi求解器进行对比,所提算法的平均求解时间仅为0.10s,自适应分块策略需要0.97s,Gurobi需要1285.15s;所提算法的面积利用率为85.06%,自适应分块策略为72.96%,Gurobi为72.91%,可见效率显著提升。该算法以0.51s的平均运行时间实现了面积利用率84.70%,标准差为0.56,优于多数对比算法。测试了5组航空货运实际案例,最多有565件货物,规划时间仅为2.81s,满足工业实时性需求。结论所提出的分块、分层叠加两阶段算法兼顾了分配效果与效率,适用于实时性和可靠性要求较高的工业应用,可为复杂物流装载优化提供有效支持。 展开更多
关键词 二维装箱问题 分块策略 面积利用率 组合优化 启发式算法
在线阅读 下载PDF
基于大规模FSP问题Block性质的SA算法 被引量:2
17
作者 金锋 宋士吉 吴澄 《系统工程与电子技术》 EI CSCD 北大核心 2007年第1期49-52,共4页
对于大规模流水线调度问题(FSP),模拟退火算法(SA)中邻域候选解的被接受概率,因邻域增大和邻域中的劣解数的增多而大大降低,SA算法的性能因而大为降低。针对这一问题,提出一种基于FSP问题Block性质的SA算法。将邻域划分成若干个子邻域,... 对于大规模流水线调度问题(FSP),模拟退火算法(SA)中邻域候选解的被接受概率,因邻域增大和邻域中的劣解数的增多而大大降低,SA算法的性能因而大为降低。针对这一问题,提出一种基于FSP问题Block性质的SA算法。将邻域划分成若干个子邻域,用子邻域中的最好解作为候选解,以提高候选解被接受的概率。引入FSP问题的Block性质,减小邻域尺寸,将搜索集中在邻域中“最有希望”的区域,进一步增强算法性能。数值仿真实验表明,该算法能在较短时间内获得大规模FSP问题的近优解。 展开更多
关键词 流水线调度问题 模拟退火算法 block性质
在线阅读 下载PDF
LBlock算法的相关密钥不可能飞来去器分析 被引量:2
18
作者 谢敏 牟彦利 《通信学报》 EI CSCD 北大核心 2017年第5期66-71,共6页
研究了相关密钥不可能飞来去器分析方法及轻量级分组密码算法LBlock在该分析方法下的安全性。将不可能飞来去器分析方法和相关密钥分析方法相结合,针对22轮LBlock给出了新的攻击。构造了15轮的相关密钥不可能飞来去器区分器,通过向前扩... 研究了相关密钥不可能飞来去器分析方法及轻量级分组密码算法LBlock在该分析方法下的安全性。将不可能飞来去器分析方法和相关密钥分析方法相结合,针对22轮LBlock给出了新的攻击。构造了15轮的相关密钥不可能飞来去器区分器,通过向前扩展3轮,向后扩展4轮,成功攻击了22轮LBlock。该攻击的数据复杂度仅为2^(51.3)个明文,计算复杂度为2^(71.54)次22轮加密。与已有结果相比,攻击的数据复杂度和计算复杂度均有明显下降。 展开更多
关键词 Lblock算法 轻量级分组密码 相关密钥 不可能飞来去器
在线阅读 下载PDF
A BLOCK VARIANT OF THE GMRES METHOD FOR UNSYMMETRIC LINEAR SYSTEMS
19
作者 GUANGYE LI CRAY RESEARCH, INC.(55F LONE OAK DRIVE EAGAN, MN 55121, USA FAX: 612-683-5276, E-MAIL: GLI@CRAY.COM) 《Wuhan University Journal of Natural Sciences》 CAS 1996年第Z1期508-514,共7页
Iterative methods that take advantage of efficient block operations and block communications are popular research topics in parallel computation. These methods are especially important on Massively Parallel Processors... Iterative methods that take advantage of efficient block operations and block communications are popular research topics in parallel computation. These methods are especially important on Massively Parallel Processors (MPP). This paper presents a block variant of the GMRES method for solving general unsymmetric linear systems. It is shown that the new algorithm with block size s, denoted by BVGMRES(s,m), is theoretically equivalent to the GMRES(s. m) method. The numerical results show that this algorithm can be more efficient than the standard GMRES method on a cache based single CPU computer with optimized BLAS kernels. Furthermore, the gain in efficiency is more significant on MPPs due to both efficient block operations and efficient block data communications. Our numerical results also show that in comparison to the standard GMRES method, the more PEs that are used on an MPP, the more efficient the BVGMRES(s,m) algorithm is. 展开更多
关键词 iterative method unsymmetric linear system block algorithm parajlel computation.
在线阅读 下载PDF
基于HMT模型的block-DCT域隐写图像移除攻击 被引量:2
20
作者 冯帆 王嘉祯 +1 位作者 马懿 张拥军 《计算机应用与软件》 CSCD 2009年第11期274-277,共4页
针对block-DCT(Discrete Cosine Transform)域加性噪声隐写图像,基于隐马尔科夫树HMT(Hiding Markov Tree)模型,提出一种新的隐写图像移除攻击算法。在分析研究HMT模型结构特点和离散的小波变换DWT(Discrete Wavelet Transform)域、bloc... 针对block-DCT(Discrete Cosine Transform)域加性噪声隐写图像,基于隐马尔科夫树HMT(Hiding Markov Tree)模型,提出一种新的隐写图像移除攻击算法。在分析研究HMT模型结构特点和离散的小波变换DWT(Discrete Wavelet Transform)域、block-DCT域系数特性的基础上,构建了准确刻画图像block-DCT变换统计特性的HMT模型,将隐写图像秘密信息的移除问题转化为约束优化求解问题。在Matlab7.0平台进行仿真实验,结果表明:基于该算法移除秘密信息后的图像,其质量(信噪比和视觉效果)明显高于传统的噪声移除方法。 展开更多
关键词 block-DCT HMT模型 EM算法 移除攻击
在线阅读 下载PDF
上一页 1 2 82 下一页 到第
使用帮助 返回顶部