578 research outputs found

    The System of Safe News Publish by Virtual Token on .NET

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    本文分析了静态口令身份认证的优缺点,口令身份认证有2个重大的缺陷:口令可以被网络上的非法用户窃听,无法防止回放攻击。本文提出了一种通用的身份认证方案,并根据这种方案设计并实现了基于虚拟Token的安全身份认证系统。这种身份认证方式属于基于动态身份认证方式中的挑战/应答模式。使用这种身份认证方式可以有效地克服口令身份认证的缺陷。在这种方式下,系统将时间作为挑战数,客户使用虚拟Token算出应答数,再根据该应答数进行系统登录。这样,时间作为挑战数是一次性的,每个时间片都是不同的挑战数,因此可以防止回放攻击;在网络中传输的是加密了的应答数,解决了口令以明文方式传递的问题。本系统是通用型的,可以适用于...This thesis analyzes the advantages and disadvantages of static-password authentication. There are two fatal flaws about password-authentication: the passwords can be wiretapped through the internet by illegal users; and this thesis is incapable to protect it from a replay attack. This thesis proposes a universal identity-authentication scheme, and furthermore, design and realize a secure identity...学位:工学硕士院系专业:计算机与信息工程学院计算机科学系_计算机应用技术学号:X200228022

    The Design and Implementation of Process Control Functions of DCS

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    DCS系统是70年代中期在PLC基础上随着现代大型工业生产自动化的不断兴起而发展起来的新型控制系统,是为满足日益复杂的控制需求应运而生的综合控制系统。目前已发展成为工业过程控制的主体设备,为提高工业生产的安全、平稳运行创造了条件,为提高工艺过程操作、控制及生产管理水平发挥了重要作用。 DCS系统紧密依赖于自动控制技术、计算机技术、通讯技术以及CRT显示技术,实现了生产过程的集中监控和集中管理,避免了常规仪表功能单一、布局分散以及计算机控制系统危险高度集中的问题。提高了工业生产过程的控制精度,降低了维护及运行成本。 随着计算机技术及通讯技术的发展,DCS系统已不再是一个局限于以单纯的过程控制...As a new type of control system based on PLC and developed with the continuous rise of modern large-scale industrial production automation in the mid-1970s, DCS is an integrated control system designed to meet the increasingly complex control requirements. For the present DCS develops into the main equipment of industrial process control, creates the conditions for improving the safety and smooth ...学位:工程硕士院系专业:软件学院_工程硕士(软件工程)学号:X201123075

    SDBSH SMEs Loans Innovation Case Study

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    目前,我国中小企业数量已占全国企业总量的99.3%,中小企业创造的最终产品和服务的价值占全国GDP的58.5%、中小企业还吸纳了75%的城镇就业人口和75%以上农村转移出来的劳动力。中小企业作为我国国民经济的一支重要力量,在推动经济发展和保持社会稳定方面发挥着重要的作用。但是中国中小企业“融资难”已经成为制约中国中小企业发展的重要“瓶颈”。 本文既从外部环境、制度体系角度对发展中小企业信贷业务进行宏观分析,又从SDBSH分行自身和中小企业融资角度进行微观分析,坚持宏观和微观相结合的分研究方法。旨在解决SDBSH分行发展中小企业信贷业务中出现的问题。 本文以大量的数据作为分析基础,从信贷实务...At present, the number of SMEs in China accounted for 99.3% of the total national enterprises, SMEs to create the value of final goods and services accounted for 58.5% of the national GDP, SMEs can also absorb 75% of urban employment and 75 percent of rural population transfer out of the labor force. SMEs in the national economy as an important force in promoting economic development and maintaini...学位:工商管理硕士院系专业:管理学院高级经理教育中心(EMBA项目)_高级管理人员工商管理硕士(EMBA)学号:X200915632

    On Internationalized Development Tendency of Art Gallery Education

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    内容摘要立足于21世纪,面对全球经济一体化的当代信息社会的变化,伴随传媒艺术信息网络技术的迅速发展与广泛应用,在教育已得到快速发展的今天,公民大众已不能仅仅满足于学校中学习,对校外社会教育需求增大,越发凸现美术馆教育的重要性是学校外社会教育的重要资源之一,也是实施社会教育的最佳场所。随着大众对文化艺术教育的重视,对文化艺术教育起支柱作用的美术馆教育得到认可,当代社会多元文化的背景要求美术馆教育功能进一步拓展,向美术馆教育国际化方向发展,充分吸取发达国家美术馆教育的实践经验,才能充分发挥美术馆教育所包含的促进国际理解,和体现通过艺术沟通多元文化的价值。所以美术馆教育向国际化发展趋势是必然的,美术...Abstract When it comes to the 21st century, with the rapid development of the current information society and the network technology in art information, the public can not only be satisfied with schooling, but more need to strengthen their need in social education off campus. It is generally acknowledged that art gallery education has become one of the important resources in off-campus ed...学位:文学硕士院系专业:艺术教育学院美术系_美术学学号:20032200

    Change in the Exchange Rate of the RMB and Employment of the Labor Force in China

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    人民币汇率变动会对中国经济带来各方面的影响,哪些影响有利于本国经济,哪些影响不利于本国经济,一直以来是学术界研究的焦点问题。但作为衡量经济发展和社会稳定的一个重要指标——就业与人民币汇率的变动是否有着某种关系,人民币汇率变动又是通过什么途径来影响着就业,我国在人民币汇率发生变动的时候应该采取何种措施来稳定就业率,这些问题较少被提及。显然,认真分析这些问题对我国的经济发展有着重要的现实意义。 本文首先对与汇率和就业的相关概念进行解析,重点讨论了名义汇率与实际汇率的区别、影响实际有效汇率计算的价格指数、劳动力市场的特征及劳动密集型产业在我国存在的现状及主要问题,回顾了学术界研究汇率变动与就业关系...The change in the exchange rate of RMB will affect many aspects of Chinese economy. What beneficial effects on economy and what effects inimical to economy has long been the focus of academic community. However, some issues are less mentioned, for instance, the relationship between change of the RMB exchange rate and employment, one of the important measures of economic development and social stab...学位:经济学硕士院系专业:经济学院经济系_西方经济学学号:X200614101

    Component Quality Improvement Based On Supply Chain Integration

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    中国汽车市场的快速发展使得国际汽车巨头纷纷来中国合资建厂,这种局面使得国内的汽车企业面临如何快速吸收国外先进技术,结合国情对国内原有的供应链系统进行改进,并逐步改善零部件的质量的问题。在供应链集成理念的基础上对零部件质量改进成为有效改善上述问题的一种很好的方法。 本文的主要研究的问题是,在供应链集成管理理念的基础上,如何对汽车零部件采购中出现的质量问题进行改进。本文结合F公司的零部件采购流程,基于供应链集成的模型,以一个关键零部件的联合质量改进为例进行深入分析。这个零部件是由F公司的供应商进行独立设计,但是在设计过程中耐久试验无法达到设计要求,作者运用MBA中所学的知识,解决了这一问题,并形...Due to the development of Chinese automotive market, many joint-venture companies are founded by international automotive tycoons. Under this situation, Chinese internal automotive corporations are facing the problem that how to absorb the international advanced technologies and improve Chinese original supplier chain. After that, they need to improve the component quality step by step. How to acc...学位:工商管理硕士院系专业:管理学院_工商管理硕士(MBA)学号:1792010115088

    Public Housing Supply and Local Governments’Behaviors--Taking the Case of Shenzhen

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    住房问题是世界性难题,住房问题的核心是居民住房消费支付能力的不足。这个观点隐含了这样一个事实,即大量中、低收入家庭的支付能力与具有适宜标准的住房价格之间存在着巨大的鸿沟,这是住房问题的症结所在,也是公共住房问题产生的根本原因,还是各国政府干预住房市场的主要原因。所以世界上几乎所有国家政府的各级政府都在不同程度上为住房供应提供政策支持,为中低收入家庭解决住房问题提供帮助。无论是发达国家,还是经济相对落后的发展中国家,没有哪个国家的全体社会成员全部是以自己购买住房来实现各自的居住愿望,世界上任何一个国家均存在着需要在政府建立的社会保障体系中解决住房问题的一部分居民,即各国政府均无一例外地发展过公共...Housing problem is globally recognized, and the kernel of the problem was insufficient housing consumption capacity of residents. This viewpoint implies the fact that a great gulf lay between the payment capability of large number of low-income families and the appropriate standards of housing prices, This is not only the crux of the problem of housing, but also the root causes of public housing p...学位:管理学硕士院系专业:公共事务学院公共管理系_行政管理学号:2005130060

    Dynamic Analysis of a High-rise-Building Structure during an Earthquake Considering Soil-Structure-Interaction

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    土-结构体系有限元模拟计算分析的复杂性与计算成本,在一定程度上限制了土与结构相互作用分析在高层建筑结构设计中的应用。上部结构数值解与土解析解耦合的土-结构相互作用计算方法,为高层建筑结构提供了有效途径。利用作者提出的耦合算法,对一个钢框架-混凝土核心筒高层结构进行地震作用下的非线性动力分析,讨论了不同强度地震和不同种类地基土对结构地震反应的影响,得出了对实际工程具有指导性意义的结论。The conventional coupling analysis based on a comprehensive finite-element(FE)model is prohibitive in terms of computational complexity and cost.The coupling method between the numerical modeling of the superstructure and the analytical modeling of the soil provides an efficient approach for SSI.This paper applies this method to a steel-reinforced concrete frame-tube high-rise building and verifies its potential through this case study.Using this method,various soil conditions and earthquake intensities are studied to explore the SSI effects,leading to meaningful conclusions to engineering practice.国家重点研发计划项目(2016YFC0701106)、国家自然科学基金项目(51261120376、5157847

    Ionic Liquids-Mediated Formation of 5-Hydroxymethylfurfural

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    5-羟甲基糠醛(5-HMf)被认为是一种非常重要的平台化合物。利用离子液体介导制备5-HMf的研究已经引起了人们越来越广泛的重视,并取得了较为理想的研究成果。本文对离子液体介导制备5-HMf的研究成果进行了系统的归纳和总结,着重介绍了离子液体作为反应溶剂和催化剂在5-HMf制备过程中的应用以及离子液体介导制备5-HMf的形成机理和影响因素,并对离子液体介导制备5-HMf的研究前景进行了展望,以期为5-HMf的进一步研究提供思路和参考。5-Hydroxymethylfurfural(5-HMF) is considered as a very important biomass-based platform compound that can be used to synthesize a broad range of liquid fuels and chemicals,which are mainly derived from fossil resources so far.The study of the production of 5-HMF in the presence of ionic liquids has increasingly attracted more attention.In this review,the recent achievements of ionic liquids-mediated formation of 5-HMF are systematically summarized,including applications of ionic liquids as reaction solvents and catalysts in the production of 5-HMF,influence factors and formation mechanisms in the ionic liquids-mediated formation of 5-HMF.The future research trends of ionic liquids-mediated formation of 5-HMF are suggested.国家重点基础研究发展计划(973)项目(No.2010CB732201);国家自然科学基金项目(No.21106121);中央高校基本业务费专项资金项目(No.2010121077)资

    Advances in production of 5-hydroxymethylfurfural from glucose

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    5-羟甲基糠醛(5-HMf)是一种重要的平台化合物,具有非常广泛的应用价值和市场前景。葡萄糖的选择性脱水是制备5-HMf的主要方法之一,也是碳水化合物降解研究中的重点和难点,现在已经受到了人们越来越广泛的重视。本文综述了近年来葡萄糖制备5-HMf的研究成果,着重介绍了5-HMf的形成机理以及制备5-HMf的催化体系与溶剂体系,并对葡萄糖制备5-HMf的研究前景进行了展望,以期为5-HMf的进一步研究提供思路和参考。5-Hydroxymethylfurfural(5-HMF)is a kind of important platform chemical compound and possesses wide application value and market prospect.Selective dehydration of glucose is one of main synthesis methods for 5-hydroxymethylfurfural and has attracted increasingly more attention.In this paper,the recent research achievements in the dehydration of glucose for preparation of 5-HMF are summarized,including formation mechanisms,catalyst systems and solvent systems,and the future research trends of 5-HMF from dehydration of glucose are prospected.国家973计划(2010CB732201);国家自然科学基金(50776035);中央高校基本业务费专项资金(2010121077)项
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