基于时空自动机的CPS建模与验证     

赵文明  陈仪香  张敏 《科技通报》2015,(1)

为了描述信息物理融合系统(cyber-physical systems,CPS)的时空一致性,一种实时规范语言STe C已经提出[1],CPS的设计和实现能否满足时空一致性显得十分重要。文中对混成自动机进行了扩展,提出了具有位置驱动特点的时空自动机。文中提出了基于时空自动机的CPS建模与验证框架。在框架中,首先使用STe C语言对CPS进行了描述并使用时空自动机对CPS进行建模。文中采用的形式化验证方法为微分动态逻辑(differential dynamic logic,DL),其操作模型为HP(hybrid program)。利用DL可以将所建模型转换为对应的HP。结合得到的HP对验证的CPS属性进行规约,最后使用定理证明器Ke Ymaera对属性进行自动化验证。  相似文献   

Hybrid Journals: Ensuring Systematic and Standard Discoverability of the Latest Open Access Articles     

Santiago Chumbe  Brian Kelly  Roddy MacLeod 《期刊图书馆员》2015,68(1-4):143-155

An important current challenge for research information providers is ensuring the automated discovery of Open Access (OA) content in hybrid journals. We found no evidence of discovery services that are able to systematically identify the crucially important free full-text availability of OA articles regardless of where and how such articles have been published (i.e., in fully OA journals or in hybrid journals). A solution is important because hybrid journals are proliferating and consequently the chances of missing OA articles is real and is happening. Nearly all of the major publishers now provide such journals in order to take advantage of recent changes in research funder requirements, and to be competitive in the new OA business model. By working with a group of scholarly publisher partners and by using standard metadata elements that publishers are already familiar with, we show a systematic and standardized manner to identify OA at the article level. Our proposal is to embed OA-related elements in the metadata freely exposed by publishers for aggregators and discovery services. For example, in the Table of Content (TOC) Really Simple Syndication feeds the publishers use to announce new journal issues and content. Based on the initial results obtained, we discuss the capabilities of our solution, and evaluate the impact produced by our application in the systematic discoverability of OA content from the participating hybrid journals, using an implementation done with the freely available journal current awareness service—JournalTOCs.  相似文献   

‘Real Pictures of Current Events’     

Christoph Raetzsch 《Media History》2015,21(3):294-312

Objectivity has been regarded as a central ideal of American journalism in the early twentieth century. The concurrent emergence of photography in the press is rarely associated with this development. The article explores the photographic legacy of journalistic objectivity by discussing a crucial phase in the development of reproduction media for images, the transition from wood engravings to halftones. The former was the dominant mode of ‘illustrated journalism’, the latter became the dominant mode of reproducing photojournalism in print in the twentieth century. The halftone process introduced an equivalence between photographs and their reproductions, obliterating the mediation that had taken place in a code of reproduction that was almost imperceptible. In the contested adoption of the halftone process, it is argued, a shifting valuation of photographs can be observed that prefigures the formulation of objectivity as a transparent code of mediation in journalism.  相似文献   

混合动力汽车动力系统仿真研究     

宋建锋  张伯俊  张蕾 《天津工程师范学院学报》2011,21(1):33-37

针对混合动力汽车中新型动力总成系统的部件构成,研究了新型动力总成的结构形式;以混合动力汽车动力性能仿真研究为目的,对总成中的动力电池、驱动电机、发动机等关键部件以及整车行驶动力学数学模型进行研究;应用Matlab/Simulink仿真软件对数学模型进行了仿真模型的实现,并讨论了模型的有效性;指出了关键总成部件的仿真应用及其方法,为混合动力汽车动力性能仿真研究工作奠定了基础技术条件。  相似文献   

混合动力助力车车架结构强度分析及轻量化设计     

姜绍忠  阎文兵  张希通 《天津工程师范学院学报》2011,21(1):45-47

以某混合动力助力车为研究对象,采用有限元方法对所设计的车架进行静态结构强度分析,得到了车架结构的应力分布图。以轻量化设计为出发点,在车架结构强度满足条件的前提下,对车架结构部分参数改进后的模型进行了进一步的分析,为混合动力助力车车架结构的优化设计以及轻量化设计提供了理论依据。  相似文献   

超轻度混合动力汽车动力转换控制策略     

张伯俊  郭家田 《天津工程师范学院学报》2011,21(3)

讨论以发动机最佳燃油经济性或电动机最佳效率为控制目标的动力转换控制策略,以油门踏板位置及蓄电池SOC状态为输入变量,设计了混合动力汽车动力转换模糊控制器,建立了整车控制仿真模型。文中阐述了由电机切换到发动机工作时发动机的起动、调速控制,以及离合器快速平稳地结合的过程。仿真结果表明：对转换车速的门限值控制模糊化能够使转换车速更加符合驾驶员对动力性的要求。  相似文献   

三维动画模型制作的混合建模流程探讨     

高彬 《Journal of Zhangzhou Technical Institute》2011,13(4):6-9

要制作出一个优秀的三维动画模型需要具备艺术修养和软件技术,同时不能忽略制作方法及工作流程的总结和提炼。本文分析了各种制作方法,初步提出混合建模的工作流程,以探索三维动画模型的制作方法。  相似文献   

A contested profession: employability,performativity and professionalism in Irish further education     

Bernie Grummell  Michael J. Murray 《Journal of educational administration and history》2015,47(4):432-450

Further education typically represents the vocational, technical and practice-based forms of education, but this is now being repositioned in a neo-liberal era that is driving a performance-based and market-orientated vision of education in the Republic of Ireland and elsewhere. The implacable drive of neo-liberal economics in everyday practice is evident in the current economic and training discourses of further education, which aim to upgrade the employability of low-skilled and marginalised sectors of the population. The article provides an overview of shifts in educational policy and practices that align Irish further education with what has occurred in the UK and elsewhere through processes of professionalisation and performativity. Analysis of the potential impact on notions of professional identity in the sector helps to articulate the principles, pedagogies and philosophies that will be vital when contesting the performance cultures of New Managerialism that seem likely to ensue. We explore the implications in terms of the policy discourses, organisational structure and professional practices of further education. We contend that changes in these areas have profound impacts on the learning and knowledge base of further education, constraining its social justice and transformative capacity for the learners at the heart of further education.  相似文献   

You escaped! How did you learn during gameplay?     

Alice Veldkamp  Johanna Rebecca Niese  Martijn Heuvelmans  Marie-Christine P. J. Knippels  Wouter R. van Joolingen 《British journal of educational technology : journal of the Council for Educational Technology》2022,53(5):1430-1458

  相似文献   

教师持续专业学习与发展:内涵、条件与评估 ——专访英国诺丁汉大学荣休教授戴杰思     

谢萍  刘芊  王馨薇 《教师发展研究》2022,6(1):13-22

在教师发展领域,基于原有的教师“专业发展(PD)”“持续/连续专业发展(CPD)”,戴杰思教授进一步提出并强调教师“持续专业学习与发展(CPLD)”的概念。他认为,CPLD项目本质上是对教师实施的系列干预活动,主要是通过有意识地为教师提供有价值的学习内容和发展机会,促进教师的专业成长,从而实现学校的积极变革和可持续发展。在CPLD项目的设计和实施过程中,要重视教师的内因作用,特别是他们的情绪韧性;同时,学校在开展CPLD项目过程中,需要从四个方面保障其有效性,即正确认识教师学习的本质与改变、重视教师专业性、提升学校领导层重视度、创建专业学习共同体。由于教师工作的复杂性,CPLD项目实施效果的测量和评估需通过构建长期、多视角立体式的测评模式探索其有效的路径和方法。  相似文献