Necessary and sufficient conditions for the existence of positive definite solutions of the matrix equation X+A T X −2 A=I

Necessary and sufficient conditions for the matrix equation X+A ^T X ^?2 A=I to have a real symmetric positive definite solution X are derived. Based on these conditions, some properties of the matrix A as well as relations between the solution X and A are derived.     

“A+一+X,B+一+Y”构式的分类及释义模板

该文以现代汉语中的“A+一+X,B+一+Y”格式为例,介绍了构建《现代汉语构式知识库》的初步工作。“A+一+X,B+一+Y”格式可根据其表义功能不同分为三个大类,十个小类。该文重点阐释了该构式表达“因果倚变义、事物交错义、状态交替义、动作行为交替义、周遍大量义、让步小量义”等6种意义的判定条件及相应的释义模板。     

电子商务：A2A是B2B2C的基础

A2A在不同场合有不同内涵,一般指“Any to Any”即“Anyone to Anyone”、“Anywhere to Anywhere”、“Anytime to Anytime”之类,对电子商务B2B、B2C、C2C(简称B2B2C)等而言,这些表述常见诸于对前台客户端的说法。事实上,在互联网环境下,一般的Any to Any并不成问题,但能真正支持B2B2C运行的A2A,是“应用到应用”即“Application to Application”,它涉及各种电子商务和企业信息化(MIS、MRPⅡ、ERP、SCM.CRM等)中各作业层面、各种流程与系统整合。本文的A2A即指“应用到应用”。     

1+1≠2

一、存在问题 某单位需要打印规章制度,纸张大小为两张4开纸张拼接。 在WPS2000环境下排版,然后设置字体向右旋转90度,同时纸张也向右旋转90度,因为纸张超过24针针式打印机最大宽度,设想打印完成后将两张纸拼接即可。 打印时出现问题,每张纸打印四五行后的每行字体均被分为两半。     

AMD Athlon X2 3800+双核

在处理器的介绍中,我们大多测试的是来自于Intel和AMD公司的高端产品,每当这两个公司推出最新,最为高端的处理器,我们几乎都会在第一时间收到评测样品,虽然我们很高兴看到高性能的处理器层出不穷,但是对于这些产品的价格却从来没有喜欢过。     

追求1+1>2

对于多功能一体机的发展,早先人们都持观望态度。但随着集成化的高速发展和一体机技术不断的完善,多功能一体机成了这几年最热门的产品之一。同传统的单一功能设备相比,多功能一体机在很多方面显示出了多种功能相加所产生的优势。在价格上,多功能一体机具有比传统单项功能的打印机、传真机等高的性价比;在技术上,一体机集成了多种先进技术,一定程度上引领了单项功能设备的发展潮流。在价格上,目前市场上的彩色喷墨打印机至少要500元左右,一台好一点的传真机要3000元,扫描仪要几百元, 而复印机少则几千元,多则要上万元,这样     

A framework to identify factors affecting the performance of third-party B2B e-marketplaces: A seller’s perspective

This study conducted exploratory research to determine factors affecting the performance of third-party B2B e-marketplaces from a seller’s perspective. Building on the relevant literature, ten factors were proposed and mapped into the domain-specific model for e-marketplaces. The performance of e-marketplaces was measured in terms of customer loyalty and trading volume. The proposed model was tested on data from 200 selling companies in Thailand participating in various third-party B2B e-marketplaces. The exploratory factor analysis generated seven factors. Partial least squares structural equation modeling was employed to test the research model. There were three major findings. First, the reputation of e-marketplace and trust in market makers, as well as transaction cost reduction and website usability, had significant effects on customer loyalty. Second, website reliability had a positive impact on trading volume. Finally, the relative advantage and number of buyers had significant effects on both customer loyalty and trading volume. These findings reveal factors previously unreported in the literature on e-marketplaces, and they can be used by practitioners to improve performance.     

PC+DC+AIO,家庭流行"P·D·A"

AIO,即All In One的缩写.在打印领域的含意是将打印机、复印机、扫描仪,还有传真机等各种单一功能的设备组合起来,成为一个具备多种功能的"一体机"产品.从表面上看,似乎产品本身的功能变得复杂了,但实际上却简化了人为的操作过程.这一设计不仅体现了一体机化繁为简的产品理念,其多种功能的组合应用实际上也为用户带来了丰富的、创造性的应用体验.     

PC+DC+AIO,家庭流行"P·D·A"

2000年,席卷中国的电脑热潮,让台式PC成为了千万家庭步入IT时代的象征;2002年,数码相机在中国的骤然风行,又把家庭摄影从传统的胶片时代带进了时尚的数字天地;数码时尚的潮流波涟不断,应接不暇的数码精品把我们的生活装点得多姿多彩.现如今,2004年,在数码打印领域以便捷、实用、人性而著称的AIO开始风靡全球.由此,PC+DC+AIO的组合模式也逐渐在中国的时尚家庭中初露端倪……     

Hyperspectral unmixing employing l1−l2 sparsity and total variation regularization

ABSTRACT

Hyperspectral unmixing is essential for image analysis and quantitative applications. To further improve the accuracy of hyperspectral unmixing, we propose a novel linear hyperspectral unmixing method based on l₁?l₂ sparsity and total variation (TV) regularization. First, the enhanced sparsity based on the l₁?l₂ norm is explored to depict the intrinsic sparse characteristic of the fractional abundances in a sparse regression unmixing model because the l₁?l₂ norm promotes stronger sparsity than the l₁ norm. Then, TV is minimized to enforce the spatial smoothness by considering the spatial correlation between neighbouring pixels. Finally, the extended alternating direction method of multipliers (ADMM) is utilized to solve the proposed model. Experimental results on simulated and real hyperspectral datasets show that the proposed method outperforms several state-of-the-art unmixing methods.     

爱普生演绎从A1+到A3+的数码影像输出

第十三届中国国际照相机械影像器材与技术博览会于2010年6月在北京国际展览中心如期开幕。展会上,除专业的摄影器材外,影像输出解决方案更是关注的焦点。其中,爱普生大幅面打印机认证经销商及合作伙伴尤为突出:如莱卡、奥林巴斯和爱色丽几大知名企业展台,分别展出了爱普生大幅面打印机从A1+到A3+的专业数码影像输出以及高品质光盘制作解决方案。     

1+1>2?

数学上,1+1=2是众所周知的。生活中,我们经常会遇到1+1≠2的情况。一对犹太人父子在休斯敦做铜器生意。为了能赚到更多的钱,父亲就经常教育儿子说:"我们犹太人唯一的财富就是智慧,当别人说一加一等于二的时候,你就应该想到大于二。"一天,父亲问:"你知道一磅铜多少钱吗?"儿子答:"35美分。"父亲说:"对,整个得州都知道一磅铜是35美分,但作为犹太人的儿子,你应该说是     

1+X证书制度下教学改革探索

1+X证书制度是近年来职业教育的一个重要制度设计,Web前端证书是首批推出的1+X证书之一.文章主要探讨在此制度下,如何对作为WEB前端开发核心内容的PHP应用开发课程进行教学改革.通过深入研究Web前端开发中级证书文件,结合校企合作内容,有针对性地进行教学改革.通过教改,使学生掌握Web前端开发的核心内容.     

An algorithm for computing positive definite solutions of the nonlinear matrix equation X + A*X −1 A = I

In this paper, an algorithm for obtaining the Hermitian positive definite solutions of the nonlinear matrix equation X?+?A*X ^?1 A?=?I is considered and discussed. The convergence of the algorithm is proved. Numerical experiments to illustrate the behavior of the algorithm are executed.     

轻松实现A1+大幅面打印

除了传统的CAD和GIS应用需要输出大幅面图纸以外,在新的应用领域如建筑业、广告业甚至个人消费者对于高精度彩色、大幅面输出的要求也越来越多。去年Epson推出的以“大幅面打印领域无局限”而著称的Stylus Pro 9000,可以实现B0+打印幅面,如今,新型Stylus Pro 7000,同样可实现1440dpi高精度6色打印,不仅打印幅面可满足A1+用户的需要,而且价位更易于接受。 Stylus Pro 7000的结构与它的前辈Stylus Pro 9000一样:送纸滚筒位于机身上后方,但只提供了一个滚筒,采用垂直走纸方式,从机身前面下方出纸。为了降     

三星笔记本电脑900X1B 移动伴侣

正以引领尖端科技为己任的三星笔记本电脑,继今年年初推出了集轻薄与高性能于一身的三星 900X3A后,在刚刚过去的秋季新品发布会上三星笔记本电脑又带来了一款更加精致灵动的 11 寸小本900X1B,与三星 900X3A 相比更加轻薄