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1.
基于小波变换的零水印算法   总被引:4,自引:0,他引:4       下载免费PDF全文
为了实施图像的版权保护,提出了一种基于小波变换的零水印算法。该算法采用经典密码学中的方法嵌入水印。为验证该算法的性能,还对该算法进行了一系列的实验,并且与另一种水印算法的实验结果进行了比较。通过比较发现,该算法对剪切、涂抹、压缩等攻击的鲁棒性远远超过了另一种水印算法。最后对该算法进行了推广,它可以用来隐藏任何数字图像的信息,不仅仅是水印。因此该算法可用于数字图像信息的隐藏。  相似文献   

2.
改进的种群分类蚁群算法及其应用   总被引:1,自引:1,他引:0       下载免费PDF全文
提出了一种改进的种群分类蚁群算法,该算法在种群分类的基础上,引入了蚂蚁的知觉感觉特性等。该算法能明显的防止蚁群算法可能出现早熟的问题,从而解决了传统蚁群算法加速收敛与早熟、停滞现象的矛盾。为了说明该算法的性能,将该算法应用到聚类分析算法中,设计了算法的模型以及算法步骤,并通过仿真实验证明了本算法的可行性和有效性。  相似文献   

3.
为提高波达方向(DOA)角估计算法的运算速度,针对对称压缩谱( MSCS)算法,提出了构建MSCS算法的多项式,求解MSCS算法的多项式根的方法。该算法不需要在半谱内搜索,保持了MSCS的镜像特性。理论分析和仿真实验表明,该算法进一步提高了MSCS运算速度;相对于求根类MUSIC算法,该算法提高了DOA估计精度,从而证明了该算法的有效性。  相似文献   

4.
蚁群算法是一种元启发式算法,其经典应用是解决旅行商问题。该算法有着先天的并行特性。介绍了该算法的两种并行实现策略,给出了蚁群算法的并行实现模型,分析了该算法并行实现需要解决的问题。  相似文献   

5.
目前IR-UWB(脉冲超宽带)测距算法中基于匹配滤波的TOA(到达时刻)估计算法存在有复杂度高和运算量大的缺点,提出了一种基于能量包络的简单TOA估计算法。该算法是一种单纯的基于相关输出最大值点检测的TOA估计算法:相关器输入接收到的多径信号和锯齿波,检测相关输出最大值点作为TOA估计。该算法比基于匹配滤波输出峰值点检测算法的运算量减小,且算法简单;无需在本地产生复杂的模板信号。通过理论分析,证明了该算法的科学性,通过仿真验证了算法的有效性,对该算法与已有的多种TOA估计算法进行了比较,分析了该算法的误差性能。  相似文献   

6.
一种克隆选择算法的收敛性分析   总被引:1,自引:0,他引:1  
针对目前的免疫算法很少涉及分析其理论模型和收敛性的问题,就免疫算法中的一种克隆选择算法提出了该算法的收敛性分析。分析过程主要分为两步:首先利用马尔可夫链建立了这种克隆选择算法的马尔可夫模型,然后在此模型的基础上进一步分析了该算法的收敛性。分析结果从数学的角度证明了该算法是收敛的。为该算法进一步的完善、实用提供了一定的理论基础。  相似文献   

7.
为了提高免疫克隆选择算法的搜索能力,提出了一种基于差分进化和免疫克隆选择算法的混合优化方法。该方法采用差分进化提高免疫克隆选择算法的抗体亲和度,并对该算法的收敛性进行了分析。为了测试该算法的有效性,将该算法应用于函数优化问题中。仿真结果表明,该方法具有更高的收敛速度和收敛精度。  相似文献   

8.
针对粒子群优化算法早熟及细菌觅食算法收敛慢的问题,提出了将量子粒子群优化与细菌觅食算法融合的一种群体智能融合算法。该算法将细菌觅食、量子计算理论及粒子群优化的优点进行融合,以细菌觅食算法为主体,将量子进化算法及粒子群优化算法嵌入其中,从而极大地提高了算法的性能。通过对三个标准函数求解和验证,结果表明该算法提高了收敛精度及速度。最后用该算法求解公共卫生应急服务设施点选址问题,取得了较好的效果,说明了该算法的有效性。  相似文献   

9.
基于蚁群算法求路径规划问题的新方法及仿真   总被引:7,自引:1,他引:6  
该文提出了一种基于蚁群算法求解路径规划问题的新方法及其仿真,蚁群算法就是对自然界中蚂蚁的寻食过程进行模拟而得出的一种模拟进化算法。与传统的算法相比,该算法的主要特点是正反馈和并行性,正反馈使得该算法能很快发现较好解,并行性使得该算法易于实现并行计算。虽然蚁群算法在时间复杂度上可能不如传统的算法,但是理论研究表明该方法是一种基于种群的鲁棒性较强的模拟进化算法。最后,利用Java语言对蚁群算法和改进的Dijkstra算法进行了仿真,并进行了比较。  相似文献   

10.
针对NP-hard性质的作业车间调度问题, 设计了一种改进的离散粒子群优化算法。引入遗传算法交叉算子和变异算子来实现粒子的更新, 并将变异思想和模拟退火算法思想融入该算法中对全局最优粒子的邻域进行局部搜索, 很好地防止了算法出现早熟收敛。通过将该算法和标准粒子群优化算法用于求解典型JSP, 计算结果对比表明, 改进的算法具有很强的全局寻优能力; 就综合解的质量和计算效率而言, 改进算法优于标准粒子群优化算法。同时, 将该算法结果与文献中其他相关算法结果进行比较, 验证了该改进算法的有效性。该算法能够有效地、高质量地解决作业车间调度问题。  相似文献   

11.
诉微分算子CCS(Calclus of Communi-cating Systems)是由英国爱丁堡大学计算机科学系的RobinMilner首先提出的。CCS是一个在数学上完整的理论算子系统,可以作为计算机通讯系统的基本理论模型。我们先简要说明一个CCS的内容。我们所作的工作是在理论上扩充地的CCS,使得我们的CCS更为一般化。在我们的观战看来,RobinMiber的CCS只不过是我们的CCS的一  相似文献   

12.
In modern service-oriented architectures, database access is done by a special type of services, the so-called data access services (DAS). Though, particularly in data-intensive applications, using and developing DAS are very common today, the link between the DAS and their implementation, e.g. a layer of data access objects (DAOs) encapsulating the database queries, still is not sufficiently elaborated, yet. As a result, as the number of DAS grows, finding the desired DAS for reuse and/or associated documentation can become an impossible task. In this paper we focus on bridging this gap between the DAS and their implementation by presenting a view-based, model-driven data access architecture (VMDA) managing models of the DAS, DAOs and database queries in a queryable manner. Our models support tailored views of different stakeholders and are scalable with all types of DAS implementations. In this paper we show that our view-based and model driven architecture approach can enhance software development productivity and maintainability by improving DAS documentation. Moreover, our VMDA opens a wide range of applications such as evaluating DAS usage for DAS performance optimization. Furthermore, we provide tool support and illustrate the applicability of our VMDA in a large-scale case study. Finally, we quantitatively prove that our approach performs with acceptable response times.  相似文献   

13.
Specularities often confound algorithms designed to solve computer vision tasks such as image segmentation, object detection, and tracking. These tasks usually require color image segmentation to partition an image into regions, where each region corresponds to a particular material. Due to discontinuities resulting from shadows and specularities, a single material is often segmented into several sub-regions. In this paper, a specularity detection and removal technique is proposed that requires no camera calibration or other a priori information regarding the scene. The approach specifically addresses detecting and removing specularities in facial images. The image is first processed by the Luminance Multi-Scale Retinex [B.V. Funt, K. Barnard, M. Brockington, V. Cardei, Luminance-Based Multi-Scale Retinex, AIC’97, Kyoto, Japan, May 1997]. Second, potential specularities are detected and a wavefront is generated outwards from the peak of the specularity to its boundary or until a material boundary has been reached. Upon attaining the specularity boundary, the wavefront contracts inwards while coloring in the specularity until the latter no longer exists. The third step is discussed in a companion paper [M.D. Levine, J. Bhattacharyya, Removing shadows, Pattern Recognition Letters, 26 (2005) 251–265] where a method for detecting and removing shadows has also been introduced. The approach involves training Support Vector Machines to identify shadow boundaries based on their boundary properties. The latter are used to identify shadowed regions in the image and then assign to them the color of non-shadow neighbors of the same material as the shadow. Based on these three steps, we show that more meaningful color image segmentations can be achieved by compensating for illumination using the Illumination Compensation Method proposed in this paper. It is also demonstrated that the accuracy of facial skin detection improves significantly when this illumination compensation approach is used. Finally, we show how illumination compensation can increase the accuracy of face recognition.  相似文献   

14.
FTDSS:高容错分布式共享存储机制   总被引:1,自引:1,他引:1  
Computerized data has become critical to the survival of an enterprise. Company must have a strategy for recovering their data should data lose. RAID is a popular mechanism to offer good fault-tolerance. But RAID can notwork well when one more disks fail. In this paper, we present an efficient Network-based high High-Tolerance Dis-tributed Shared Storage mechanism called FTDSS. FTDSS makes use of disk space of node in Network to build alarge pubhc shared storage space. Users can read/write their file from/to the public storage space from node of net-work. Physically File is stored in each node in form of data fragment or XOR verify fragment. Because of redundant XOR fragments, file is available even when two more nodes fail. FTDSS realize distant redundant srorage. At last,this paper use experiment to prove that FTDSS can offer high. fault-tolerance and advanced performance.  相似文献   

15.
The theses of existonness, compoundness, and polyadness are proved. The consistency of these theses with the reversibility principle is founded. Existential foundations of the composition paradigm are constructed. __________ Translated from Kibernetika i Sistemnyi Analiz, No. 2, pp. 3–12, March–April 2008.  相似文献   

16.
A major challenge in nanoscience is the design of synthetic molecular devices that run autonomously (that is, without externally mediated changes per work-cycle) and are programmable (that is, their behavior can be modified without complete redesign of the device). DNA-based synthetic molecular devices have the advantage of being relatively simple to design and engineer, due to the predictable secondary structure of DNA nanostructures and the well-established biochemistry used to manipulate DNA nanostructures. However, ideally we would like to minimize the use of protein enzymes in the design of a DNA-based synthetic molecular device. We present the design of a class of DNA-based molecular devices using DNAzyme. These DNAzyme-based devices are autonomous, programmable, and further require no protein enzymes. The basic principle involved is inspired by a simple but ingenious molecular device due to Tian et al. [Y. Tian, Y. He, Y. Chen, P. Yin, C. Mao, A DNAzyme that walks processively and autonomously along a one-dimensional track, Angew. Chem. Intl. Ed. 44 (2005) 4355–4358] that used DNAzyme to traverse on a DNA nanostructure, but was not programmable in the sense defined above (it did not execute computations).  相似文献   

17.
《Ergonomics》2012,55(12):1597-1618
Although often suggested as a control measure to alleviate musculoskeletal stresses, the use of mechanical assistance devices (i.e. manipulators) in load transfers has not been extensively studied. Without data describing the biomechanical effects of such devices, justification for decisions regarding implementation of such tools is difficult. An experimental study of two types of mechanical manipulators (articulated arm and overhead hoist) was conducted to determine whether biomechanical stresses, and hence injury risk, would be alleviated. Short distance transfers of loads with moderate mass were performed both manually and with manipulator assistance under a variety of task conditions. Using analysis and output from new dynamic torso models, strength demands at the shoulders and low back, lumbar spine forces, and lumbar muscle antagonism were determined. Strength requirements decreased significantly at both the shoulders and low back when using either manipulator in comparison with similar transfers performed manually. Peak spine compression and anteriorposterior (a-p) shear forces were reduced by about 40% on average, and these reductions were shown to be primarily caused by decreases in hand forces and resultant spinal moments. Two metrics of muscular antagonism were defined, and analysis showed that torso muscle antagonism was largest overall when using the hoist. The results overall suggest that hoist-assisted transfers, although better in reducing spine compression forces, may impose relatively higher demands on coordination and/or stability at extreme heights or with torso twisting motions. The relatively higher strength requirements and spine compression associated with the articulated arm may be a result of the high inertia of the system. Potential benefits of practice and training are discussed, and conclusions regarding implementation of mechanical manipulators are given.  相似文献   

18.
19.
基于LDA话题演化研究方法综述   总被引:6,自引:1,他引:5  
现实生活中不断有新话题的产生和旧话题的衰减,同时话题的内容也会随着时间发生变化。自动探测话题随时间的演化越来越受到人们的关注。Latent Dirichlet Allocation模型是近年提出的概率话题模型,已经在话题演化领域得到较为广泛的应用。该文提出了话题演化的两个方面 内容演化和强度演化,总结了基于LDA话题模型的话题演化方法,根据引入时间的不同方式将目前的研究方法分为三类 将时间信息结合到LDA模型、对文本集合后离散和先离散方法。在详细叙述这三种方法的基础上,针对时间粒度、是否在线等多个特征进行了对比,并且简要描述了目前广泛应用的话题演化评测方法。文章最后分析了目前存在的挑战,并且对该研究方向进行了展望。  相似文献   

20.
BOOTSTRAP methodology was initially developed in an ESPRIT project together with European industry. After February 1993, the methodology has been managed and further developed by a European Economic Interest Group, called BOOTSTRAP Institute. BOOTSTRAP methodology version 3.0 was released in September 1997. It is compliant with the ISO/IEC software engineering standard number 15504, the emerging standard on software process assessment. The core of the methodology consists of an assessment model and method. The assessment model of the methodology version 3.0 was updated to align with the ISO 12207 life-cycle and 15504 reference model requirements. In addition to the Process and Capability dimensions, it contains a Technology dimension. The Process dimension contains 33 different processes organised in six clusters: Organisation, Life Cycle Dependent, Management, Support, Customer-Supplier, and Process Related. The Capability dimension consists of six levels, each level consisting of one or more process attributes, adopted from ISO 15504. An assessment is conducted at SPU and project levels. The BOOTSTRAP Institute organises and co-ordinates assessor training and registration scheme. BOOTSTRAP methodology is being used in two European projects: SPAM and PROFES.  相似文献   

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