优秀的流式媒体播放技术

本文分析了几种流式媒体的发展历史 ,重点介绍了微软的流媒体解决方案。流媒体的提出对于解决视、音频信息在网络中的传输具有非常重要的意义 ,同时对于远程教学中的课程注册也提出了非常好的解决方案。     

The role of corporate technology strategy and patent portfolios in low-, medium- and high-technology firms

Previous research into technology strategies and patent portfolios has focused on high-technology firms, whereas low- and medium-technology companies have been relatively neglected. Therefore, we analyze how corporate technology strategy and the size and composition of patent portfolios affect the performance of low-, medium- and high-technology firms. Data from 136 European companies are used to examine four hypotheses relating financial performance to technological diversification, technological aggressiveness, patent portfolio size, and patent portfolio quality. The cross-industry sample allows analyzing the different consequences of these strategic parameters in low-, medium- and high-technology firms by considering technological intensity as a moderator. Our first finding is that the positive impact of technological aggressiveness is limited in low- and medium-technology companies. Secondly, technological diversification has a positive effect in high-technology firms and a negative effect in low-technology firms. Thirdly, patent portfolio size has a positive effect only in high-technology firms. Finally, patent portfolio quality has an equally positive influence on all firms’ performance. In part, these results conflict with the findings of previous research into high-technology companies, and they call for rethinking the role of technology strategies and intellectual property portfolios in firms across industries.     

环境规制与行业异质性对制造业企业技术创新的影响——基于我国沿海与内陆地区的比较

基于行业异质性视角,以2010年—2015年我国省级制造业规模以上企业为样本,将环境规制划分为正式型与非正式型两类,对比分析了沿海与内陆地区环境规制、行业异质性对企业技术创新影响的差异。研究发现：(1)从制造业全行业来看,正式型环境规制对技术创新的影响作用在沿海与内陆地区均显著为正;非正式型环境规制对技术创新的影响作用在沿海地区显著为正,在内陆地区作用不显著;环境规制强度对技术创新的影响作用在沿海地区显著为负,在内陆地区显著为正。(2)环境规制对高污染行业的技术创新作用在沿海地区显著为正,在内陆地区显著为负。(3)环境规制对高搬迁成本行业的技术创新作用在沿海地区显著为正,在内陆地区显著为负。     

Fractional order sliding mode control of a pneumatic position servo system

Gas flow has fractional order dynamics; therefore, it is reasonable to assume that the pneumatic systems with a proportional valve to regulate gas flow have fractional order dynamics as well. There is a hypothesis that the fractional order control has better control performance for this inherent fractional order system, although the model used for fractional controller design is integer order. To test this hypothesis, a fractional order sliding mode controller is proposed to control the pneumatic position servo system, which is based on the exponential reaching law. In this method, the fractional order derivative is introduced into the sliding mode surface. The stability of the controller is proven using Lyapunov theorem. Since the pressure sensor is not required, the control system configuration is simple and inexpensive. The experimental results presented indicate the proposed method has better control performance than the fractional order proportional integral derivative (FPID) controller and some conventional integral order control methods. Points to be noticed here are that the fractional order sliding mode control is superior to the integral order sliding mode counterpart, and the FPID is superior to the corresponding integral order PID, both with optimal parameters. Among all the methods compared, the proposed method achieves the highest tracking accuracy. Moreover, the proposed controller has less chattering in the manipulated variable, the energy consumption of the controller is therefore substantially reduced.     

基于组合模型的“十四五”期间中国科技人才需求预测

选用《中国统计年鉴(1999—2020)》中我国(不含港澳台地区)R&D人员全时当量数据,以2012—2019年数据构建灰色GM(1,1)预测模型,以1995—2019年数据构建时间序列模型,并将两者组合,对"十四五"期间我国的科技人才需求总量进行预测.预测结果显示,"十四五"期间科技人才需求逐年上升,科技人才的全时当量需求规模达到647.46万人年,科技人才需求端压力较大.基于预测结果,本文认为应关注科技人才的需求与供给,从人才规划、培养、管理、使用等方面保障科技人才数量积累、素质提升和充分利用.     

高职“现代纺织技术”特色专业建设的探索

高职＂现代纺织技术＂专业建设中存在诸多问题,高职院校应紧紧围绕社会需求办学,明确专业人才培养目标。以特色专业建设为契机,精心设计专业人才培养方案,以培养应用性人才为核心任务,加强校内外实训基地建设,建立健全教学管理制度和教学质量监控体系。     

高效课堂技术化模型的内在关联及平衡点

先进理念与有力技术的完美结合是缔造现代课堂典范形态的两大支撑点。当代高效课堂改革的内在线路之一是寻求一条高效课堂理念与现代技术文化之间更为完美的结合方式。技术是＂形而上＂的思想与＂形而下＂的工具组成的有机体,高效课堂理念在技术文化的技术思维、技术手段、技术工艺等层面都能找到相应的结合点。高效课堂理念技术化过程的实质是先进课改理念与技术文化全面融合的立体化过程,是先进课改理念借技术思维、技术手段、技术工艺来付诸实践的过程。这一过程有三个关键环节：课改理念的精确化、课堂手段的现代化与教学过程的工艺化,构成了高效课改理念技术化的＂三部曲＂。如何在技术与艺术之间寻求一种平衡,努力实现理念与实践在技术条件中的完美耦合与整合匹配,是当代高效课堂改革的重要思路。这一平衡的实现需要重点解决三大平衡：有形模式与无形变革间的平衡、理念创新与技术配合间的平衡、学习环境与教学控制间的平衡。     

三重视角下融合技术的学科教学知识之内涵与特征

TPACK（融合技术的学科教学知识）是信息时代全新的教师知识框架,对于理解信息化教学诉求之下的教师知识发展具有重要的意义。TPACK的知识内涵与特征,亟待更加丰富而深入的阐释。通过文献分析,首次提出了理解TPACK内涵的三重视角：在跨学科视角下,TPACK是教师对跨学科认知方式与信息技术的交互所做出的明智设计和无缝衔接;在解构视角下,TPACK是教师对信息技术与特定学科（或主题）活动和特定主题表征之间的有机融合;在纵深视角下,TPACK是教师采纳技术并使之融入学科教学的多方面进阶与渐进式改变。据此,进一步阐述了TPACK的特征为融合转化性、复杂多面性、动态层级性、实践生成性和个人创造性。     

Is small actually big? The chaos of technological change

In this paper, we develop themes from complexity and chaos theory that help to explain the technological change process. We apply two quantifiers, correlation dimensions and Lyapunov exponents, to examine the signs and degrees of chaotic technological dynamics. To illustrate our ideas, we study the development of electronic displays from 1976 to 2010, using patent data. The results of the chaos model are matched against the profiles of patent citations. Our analysis contributes to the development of a chaotic model of technological change.     

中国彩电总装企业的技术学习

本从产品和工艺技术的角度，总结了中国彩电总装企业的技术学习行为及其特点，指出了总装企业主要是学习了产品的整机设计能力和装配操作技能，导致了总装企业较窄的知识基础，因此，总装企业的“追赶”主要是专注于国内同质且可大批量生产产品的生产能力和国内市场份额的扩张，难以升级到高端和正在增长的差别化产品市场。因此，总装企业需要加强与国内供应商的后向联系，以创造更广和更多样化的知识基础，尤其在关键零部件和生产设备的生产和设计方面。