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101.
现有基于边信息的半监督维数约减算法大都是直接将保留边信息和数据拓扑结构的目标函数相加,因此数据拓扑结构中的错误连接不会因已知的边信息而得到修正.提出通过边信息传播及修正机制将边信息融入到数据拓扑结构图中的方法,从而在保留边信息的同时保留更为真实的数据拓扑结构信息.实验结果表明本文所提出的算法较之其它算法,对数据降维后用于分类时可取得较高的准确率,且算法对创建的KNN图中的参数K最具鲁棒性. 相似文献
102.
基于免疫算法和反向传播神经元网络的无线网络入侵检测研究 总被引:1,自引:0,他引:1
为了能够检测到无线网络系统中已知和未知类型的入侵者,提高无线网络系统的安全性,在对网络数据分析和研究的基础上,提出一种基于免疫算法和反向传播神经元网络的入侵检测方法。首先利用免疫算法对网络数据进行预处理,再运用反向传播神经元网络对处理后的数据(程序)进行识别。实验表明用该方法检测无线网络系统中的新型入侵者是可行、有效的,检测入侵者的准确率可达到97%。 相似文献
103.
Shape-from-shading (SFS) aims to reconstruct the three-dimensional shape of an object from a single shaded image. This article
proposes an improved framework based on belief propagation for computing SFS. The implementation of the well-known brightness,
integrability and smoothness constraints inside this framework is shown.
We implement the constraints as probability density functions. For example, the brightness constraint is a two-dimensional
probability density function that relates all possible surface gradients at a pixel to their probability given the pixel intensity.
A straightforward extension of the framework to photometric stereo is presented, where multiple images of the same scene taken
under different lighting conditions are available.
The results are promising, especially since the solution is obtained by iteratively applying simple operations on a regular
grid of points. The presented framework therefore can be implemented in parallel and is a reasonably likely biological scheme. 相似文献
104.
105.
Toby Hopp 《Behaviour & Information Technology》2016,35(5):380-393
This study investigated the role of social capital affinity (the sense of community and likeness felt for people online) and the experience of flow (concentrated engagement in/enjoyment of an activity) as antecedents to a variety of positive outcomes associated with the use of e-commerce sites. Also, based on socio-emotional selectivity theory, the current study assessed the influence of age on social capital affinity and flow. As a subset of data from a telephone sample of Internet users in the USA, 282 e-commerce users responded to questions about site satisfaction, perceived focused and incidental knowledge-gains, and affirmation, in addition to flow and social capital affinity. As predicted by socio-emotional selectivity theory, there was a negative relationship between age and social capital affinity and flow. Flow, for its part, mediated the effects of age and social capital affinity on perceived focused and incidental knowledge-gain, satisfaction and affirmation among participants reporting e-commerce use. Finally, the current results indicated that satisfaction and perceived incidental learning predicted participant affirmation for their chosen e-commerce site. 相似文献
106.
针对图像全局立体匹配精度高、计算量大的问题,提出基于mean shift图像分割的全局立体匹配方法。首先,通过mean shift算法对图像进行分割,获取图像同质区域数量和区域的标号。在计算匹配代价时,根据像素所属的分割区域,对像素进行筛选,从而提高匹配代价计算速度;其次,在代价聚合前,将mean shift算法获取的同质区域数K值赋值给K-means聚类算法,对像素再次聚类,提高立体匹配精度和速度;最后通过TRW-S置信传播解决能量最小化问题。实验表明,该算法明显提高了匹配的准确性和速度,与单纯的全局匹配算法相比,具有更大的优势。 相似文献
107.
Ozlem Ozgun Gökhan Apaydin Mustafa Kuzuoglu Levent Sevgi 《Computer Physics Communications》2011,182(12):2638-2654
A MATLAB-based one-way and two-way split-step parabolic equation software tool (PETOOL) has been developed with a user-friendly graphical user interface (GUI) for the analysis and visualization of radio-wave propagation over variable terrain and through homogeneous and inhomogeneous atmosphere. The tool has a unique feature over existing one-way parabolic equation (PE)-based codes, because it utilizes the two-way split-step parabolic equation (SSPE) approach with wide-angle propagator, which is a recursive forward–backward algorithm to incorporate both forward and backward waves into the solution in the presence of variable terrain. First, the formulation of the classical one-way SSPE and the relatively-novel two-way SSPE is presented, with particular emphasis on their capabilities and the limitations. Next, the structure and the GUI capabilities of the PETOOL software tool are discussed in detail. The calibration of PETOOL is performed and demonstrated via analytical comparisons and/or representative canonical tests performed against the Geometric Optic (GO) + Uniform Theory of Diffraction (UTD). The tool can be used for research and/or educational purposes to investigate the effects of a variety of user-defined terrain and range-dependent refractivity profiles in electromagnetic wave propagation.
Program summary
Program title: PETOOL (Parabolic Equation Toolbox)Catalogue identifier: AEJS_v1_0Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEJS_v1_0.htmlProgram obtainable from: CPC Program Library, Queen?s University, Belfast, N. IrelandLicensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.htmlNo. of lines in distributed program, including test data, etc.: 143 349No. of bytes in distributed program, including test data, etc.: 23 280 251Distribution format: tar.gzProgramming language: MATLAB (MathWorks Inc.) 2010a. Partial Differential Toolbox and Curve Fitting Toolbox requiredComputer: PCOperating system: Windows XP and VistaClassification: 10Nature of problem: Simulation of radio-wave propagation over variable terrain on the Earth?s surface, and through homogeneous and inhomogeneous atmosphere.Solution method: The program implements one-way and two-way Split-Step Parabolic Equation (SSPE) algorithm, with wide-angle propagator. The SSPE is, in general, an initial-value problem starting from a reference range (typically from an antenna), and marching out in range by obtaining the field along the vertical direction at each range step, through the use of step-by-step Fourier transformations. The two-way algorithm incorporates the backward-propagating waves into the standard one-way SSPE by utilizing an iterative forward–backward scheme for modeling multipath effects over a staircase-approximated terrain.Unusual features: This is the first software package implementing a recursive forward–backward SSPE algorithm to account for the multipath effects during radio-wave propagation, and enabling the user to easily analyze and visualize the results of the two-way propagation with GUI capabilities.Running time: Problem dependent. Typically, it is about 1.5 ms (for conducting ground) and 4 ms (for lossy ground) per range step for a vertical field profile of vector length 1500, on Intel Core 2 Duo 1.6 GHz with 2 GB RAM under Windows Vista. 相似文献108.
Bing-Kun Bao Author Vitae Bingbing Ni Author VitaeAuthor Vitae Shuicheng Yan Author Vitae 《Pattern recognition》2011,44(3):598-606
With fast growing number of images on photo-sharing websites such as Flickr and Picasa, it is in urgent need to develop scalable multi-label propagation algorithms for image indexing, management and retrieval. It has been well acknowledged that analysis in semantic region level may greatly improve image annotation performance compared to that in the holistic image level. However, region level approach increases the data scale to several orders of magnitude and proposes new challenges to most existing algorithms. In this work, we present a novel framework to effectively compute pairwise image similarity by accumulating the information of semantic image regions. Firstly, each image is encoded as Bag-of-Regions based on multiple image segmentations. Secondly, all image regions are separated into buckets with efficient locality-sensitive hashing (LSH) method, which guarantees high collision probabilities for similar regions. The k-nearest neighbors of each image and the corresponding similarities can be efficiently approximated with these indexed patches. Lastly, the sparse and region-aware image similarity matrix is fed into the multi-label extension of the entropic graph regularized semi-supervised learning algorithm [1]. In combination they naturally yield the capability of handling large-scale dataset. Extensive experiments on NUS-WIDE (260k images) and COREL-5k datasets validate the effectiveness and efficiency of our proposed framework for region-aware and scalable multi-label propagation. 相似文献
109.
Zhongsheng HuaAuthor Vitae 《Decision Support Systems》2011,51(3):671-681
With the increasing interdependence among supply chain members, bankruptcy of a supply chain member may be caused by operational decisions of other members. To investigate how bankruptcy occurs and propagates in supply chain networks, we build a multi-agent simulation model for a two-stage supply chain that consists of multiple upstream manufacturers and multiple downstream retailers. Based on the developed simulation model, we study impacts of various operational parameters and decisions, such as horizontal competition among retailers, order allocation strategies of retailers, wholesale price of manufacturers, characteristics of market demand and number of retailers, on bankruptcy propagation. Since many operational decisions of a firm are made under financial constraints, we also investigate the linkage between firm's operational risks and financial decisions (e.g., the maximal risk of cash flow that a member is willing to take, and the up-front payment proportion of retailers in a two-period payment policy). Experimental results reveal that operational interactions between supply chain members and operational decisions made by supply chain members are important causes of bankruptcy propagation, but impacts of these operational parameters and decisions depend on financial decisions. These observations indicate that supply chain members can moderately hedge their operational risk through financial decisions. 相似文献
110.