天下视频Flash 制作下载转换通

宽带流行了,播客兴起了,FLV吃香了,菜鸟也坐不住了,迅即抱回了DV,开通了播客。历经N天修炼,Flash视频终于成为菜鸟的拿手好菜之一。播客的兴起,使得Flash视频(FLV)格式大行其道。究其原因,不外乎FLV视频避免了不安装特定视频插件就     

让经典延续! Win8开始菜单全攻略

没错,开始菜单从Windows95开始被正式应用到现在,她所带来的便捷已经深入人心,突然升级到Win8了,开始菜单取消了,我们似乎一下子变得无所适从,找不到重启、关机的按钮了,找不到控制面板了,找不到打印机了,找不到需要的程序了,才刚熟悉了在开始菜单中快速搜索文件,现在又不知道     

产品外形协同设计系统的研究与实现*

提出了协同设计工作模式,给出了系统的工作流程,定义了用户的权限分配,研究了基于交互日志的传输方式,讨论了协同设计过程中的实时更新机制.最后采用了基于MVC的体系结构构建了一个原型系统,该系统在实际应用中,验证了该技术思路的正确性.     

多媒体技术在小学数学教学中的作用

科学技术的日新月异发展,推动了素质教育的进程,多媒体技术已经走进了课堂,本文阐述了小学数学教学应用多媒体技术,激发了学生浓厚的学习兴趣,化解了教学重点难点,营造了良好的氛围,优化了课堂教学,提高了课堂教学效率。     

2011年1-12月美国工业机器人统计数据

北美地区2011年工业机器人订单为19337台套,一举超越了2005年历史最高水平的18228台。较2010年增长47%,合11.7亿美元,金额增长38%。从行业领域看,汽车零部件厂商工业机器人订单大增,增加了77%,汽车行业订单增加了59%。金属加工工业增加了56%,半导体、电子器件、光学仪器等增加了24%。从用途来看,弧焊机器人增加了66%,点焊增加了78%,装配增加了63%,胶合增加了42%,搬运增加了30%。具体情况见下面图表。     

机会! 有木有?

<正>摩托罗拉移动被谷歌收购了,诺基亚和微软联姻了,惠普退出Web OS了,即使PC业务,惠普也有意让出了,乔布斯辞职了,苹果的威胁是不是会有所降低了?资本市场其实已经给出了最好的说明。市场在变化,这个时候对竞争对手而言,无疑是最好的一次追赶的机会。谷歌跑步入场,跑马圈地正当时摩托罗拉终于在挣扎了许久之后还是放弃了移     

基于电磁感应的矿井探测方法研究及仿真

本文首先分析了矿井探测中遇到的信号干扰种类,结合噪声信号的特点,提出了基于电磁感应的矿井探测方法,给出了其原理图和设计原则.然后详细论述了电磁感应探测方法的具体实现,给出了各主要测试参数的计算公式,明确了在探测过程中需要采集的各种信号.为了验证提出的电磁感应探测方法,最后采用了MATLAB建立了仿真测试模型,并给出了仿真测试结果.     

发挥多媒体技术的优势,营造轻松的学习氛围

小学语文教学应用于多媒体技术,实现二者的整合,营造了宽松的学习环境,突出了学生的主体地位,激发了学生的创新意识。多媒体技术的应用为小学语文教学改革带来了机遇与挑战,为学生提供了全面的感性材料,活跃了教学气氛,激发了学习欲望。多媒体技术与小学语文教学有机结合,形成了一种全新的学习方式。本文试就发挥多媒体技术的优势,营造轻松的学习氛围进行了阐述。     

IT融资：冬去春来，谁当领跑

地震震动了人心,奥运鼓舞了人心,金融海啸席卷了人心。 失业了,郁闷;降息了,还银行贷款少了,高兴。人们在悲喜交织中动荡着。     

基于条码的移动护理系统

在PDA上集成了一维条码扫描组件,建立了移动护理系统,系统软件采用B/S结构,具有病人识别、医嘱执行管理、检验标本采集和体征录入等功能,优化了护理工作流程,提高了护士的工作效率,提升了护理质量,改善了医院护理管理,减少了医疗差错。     

协作机器人的构型分析研究

针对协作机器人的构型分析研究,得出了偏置是影响机器人构型的一个重要因素。首先,对现有典型协作机器人的构型进行分析,通过构型间的内在联系与演化过程得到构型之间的差异。然后利用构型之间的差异引出了偏置的定义,并通过偏置对关节运动范围的影响将其分为S型偏置和Y型偏置。最后以全局性能指标、工作空间体积指标和灵活工作空间指标为性能评价标准,对iiwa、Sawyer、Yumi三种典型构型的性能进行了仿真。通过对比分析可知,偏置的存在使构型的全局性能和工作空间体积性能降低,但对灵活工作空间性能有提高作用。结果表明偏置是影响机器人性能的重要因素,该分析研究为协作机器人的构型设计提供了理论依据。     

群智能新研究:角色?匹配的狼群劳动分工

启发于生物狼群群体的劳动分工行为,本文提出一种新颖的角色?匹配狼群劳动分工方法。通过剖析自然狼群的生物学行为,概括提炼出狼群劳动分工行为的个体任务的专职化、个体角色可塑性和任务分配均衡性3个典型特征,并建立了生物狼群劳动分工行为与普适性任务分配问题之间的仿生映射关系;从狼群“个体?个体”+“个体?环境”的交互方式角度出发,分析了角色?匹配的狼群劳动分工的个体角色转换和任务调整机制,研究了狼群角色?匹配的柔性劳动分工机制,提出了一种新的群智能方法,即角色?匹配的狼群劳动分工方法;将狼群的角色?匹配劳动分工与蚁群的刺激?响应劳动分工和蜂群的激发?抑制劳动分工进行了比较分析,并展示出角色?匹配狼群劳动分工方法的应用前景。     

Expert system verification and validation: a survey and tutorial

Assuring the quality of an expert system is critical. A poor quality system may make costly errors resulting in considerable damage to the user or owner of the system, such as financial loss or human suffering. Hence verification and validation, methods and techniques aimed at ensuring quality, are fundamentally important. This paper surveys the issues, methods and techniques for verifying and validating expert systems. Approaches to defining the quality of a system are discussed, drawing upon work in both computing and the model building disciplines, which leads to definitions of verification and validation and the associated concepts of credibility, assessment and evaluation. An approach to verification based upon the detection of anomalies is presented, and related to the concepts of consistency, completeness, correctness and redundancy. Automated tools for expert system verification are reviewed. Considerable attention is then given to the issues in structuring the validation process, particularly the establishment of the criteria by which the system is judged, the need to maintain objectivity, and the concept of reliability. This is followed by a review of validation methods for validating both the components of a system and the system as a whole, and includes examples of some useful statistical methods. Management of the verification and validation process is then considered, and it is seen that the location of methods for verification and validation in the development life-cycle is of prime importance.     

A method of defuzzification based on the approach of areas' ratio

The new method of defuzzification of output parameters from the base of fuzzy rules for a Mamdani fuzzy controller is given in the paper. The peculiarity of the method is the usage of the universal equation for the area computation of the geometric shapes. During the realization of fuzzy inference linguistic terms, the structure changes from the triangular into a trapezoidal shape. That is why the universal equation is used. The method is limited and can be used only for the triangular and trapezoidal membership functions. Gaussian functions can also be used while modifying the proposed method. Traditional defuzzification models such as Middle of Maxima − MoM, First of Maxima − FoM, Last of Maxima − LoM, First of Suppport − FoS, Last of Support − LoS, Middle of Support − MoS, Center of Sums − CoS, Model of Height − MoH have a number of systematic errors: curse of dimensionality, partition of unity condition and absence of additivity. The above-mentioned methods can be seen as Center of Gravity − CoG, which has the same errors. These errors lead to the fact that accuracy of fuzzy systems decreases, because during the training root mean square error increases. One of the reasons that provokes the errors is that some of the activated fuzzy rules are excluded from the fuzzy inference. It is also possible to increase the accuracy of the fuzzy system through properties of continuity. The proposed method guarantees fulfilling of the property of continuity, as the intersection point of the adjustment linguistic terms equals 0.5 when a parametrized membership function is used. The causes of errors and a way to delete them are reviewed in the paper. The proposed method excludes errors which are inherent to the traditional and non- traditional models of defuzzification. Comparative analysis of the proposed method of defuzzification with traditional and non-traditional models shows its effectiveness.     

并行模糊测试综述

软件脆弱性已成为互联网安全的主要威胁来源,软件脆弱性分析技术的重要性日益突出。模糊测试是脆弱性分析的热点技术之一,通过持续生成测试用例、动态监控目标代码执行和反馈调节变异策略的方法尝试触发程序异常,具有部署便捷、适用性广和效果直观的优点。随着测试目标的复杂性增加,从业人员对模糊测试的效率提出了更高的要求。并行模糊测试通过并行执行、任务分解和共享信息等方法提高脆弱性分析的效率。首先,分析了基于覆盖反馈的模糊测试面临的主要挑战;之后,探讨了并行模糊测试的解决思路和方案,从系统结构、任务划分、语料库共享和崩溃去重等方面对并行模糊测试进行了综述;最后,总结了现有并行模糊测试的优缺点,并对未来发展方向进行了展望。     

氯乙烯精馏控制模式的分析及实践

在对氯乙烯精馏这个复杂生产过程工艺及控制的分析基础上,提出了低沸塔回流、低塔釜加热、中间过料、高塔回流、高塔釜加热、成品冷凝等回路的控制模型。并介绍了用开放的DCS进行的组态、调试过程。因其图形化组态工具的直观、灵活、功能强,使复杂的控制问题简单化,且控制对工况变化的适应性强。经生产实际运行表明,产品质量、生产能力均超过预期值。     

构建安全的局域网策略

网络安全是一门涉及计算机科学、网络技术、密码技术、信息安全技术、应用数学、教论、信论等多种学科的综合性学科,它涉及的因素主要包括物理安全、系统安全、信息安全和文化安全等范围。局域网络中人为的、非人为的,有意的、无意的;非法用户入侵、计算机病毒、黑客的不断侵袭等随时威胁局域网的安全。随着计算机网络技术迅速发展,网络安全问题也日渐突出。该文分析了威胁局域网安全的主要因素,探讨了从物理环境、网络层、应用层以及管理制度方面,运用VPN、NAT、VLAN、IDS、身份验证等技术构建安全局域网的策略。     

计算机硬件系统常见故障的分析处理

归纳总结了计算机用户在日常工作、生活中可能碰到的多种代表性的电脑软硬件故障和问题及解决方法。各种故障问题类型和故障排除思维习惯来编排,具体包括开关机故障、死机故障、显示故障、声音故障、存储设备故障、CPU故障、内存故障、主板故障。在碰到电脑故障时,能快速判断和解决一些有规律可循的常见故障,以及如何维护电脑、如何避免电脑故障。     

Remote sensing of spring phenology in boreal regions: A free of snow-effect method using NOAA-AVHRR and SPOT-VGT data (1982-2004)

Measurements of spring phenological dates in boreal regions using NDVI can be affected by snowmelt. This impacts the analysis of interannual variations in phenology and the estimates of annual carbon fluxes. For these two objectives, snowmelt effect must be removed from the phenological detection. We propose a methodology for determining the date of onset of greening in the 1982-2004 period using SPOT-VEGETATION (VGT) and NOAA Advanced Very High Resolution Radiometer (AVHRR) data. From 1998 onwards, the date of onset of greening is taken as the date at which the Normalized Difference Water Index (NDWI), calculated from SPOT-VGT near and short-wave infrared bands, starts increasing. This index decreases with snowmelt but increases with vegetation greening. For the 1982-2001 period, the date of onset of greening is the date at which AVHRR-NDVI equals a pixel specific threshold (PST), determined using the results of the NDWI method in the years common to the two datasets. The methods are validated using in situ measurements of the dates of leaf appearance. RMSE of 6.7 and 7.8 days, respectively, is found using NDWI-VGT and PST-NOAA methodologies, and the difference between the two methodologies in the common years is small. Very importantly, the dates are not biased. The interannual variations of the 23-year spring phenology dataset on the study area in northern Eurasia are analysed. In average over the study area, an advance of 8 days and a delay of 3.6 days are, respectively, found over the periods 1982-1991 and 1993-2004. These results confirm and complete previous studies about the greening trend, remove the uncertainty due to snow, and may improve carbon budget calculations.     

联邦开发过程中的校核、验证与确认（VV＆A）

对联邦的VV＆A不仅能够使每一步的工作得到跟踪和衡量,还使每一步能够减少多余的工作量,巩固需要加强的工作,明确开发人员的角色和职责,从而使人力、时间、资金等资源得到更加有效率的利用,仿真的结果变得更加可预测和准确,在很大程度上减少了编程的风险.联邦成员描述了仿真模型的各对象类、交互类、相关的属性、参数等信息,而联邦是各联邦成员的有机集成,构成具有特定功能的仿真系统.因此,联邦成员的正确性是联邦正确性的前提,决定了仿真系统的成败.在VV＆A的过程中,最好采用一些自动化工具以便于工作,同时要根据具体仿真系统的实际情况来确定VV＆A所需要作的工作.