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王华 《计算机工程与应用》1999,35(5):52-54
信息安全是人们密切关注的重要问题。目前,数字签名的讨论和分析中,大多数研究的焦点都集中在签名体制的安全和控制验证方的验证能力这一方面;而对签名方却没有什么控制,但在很多实际应用中需要控制签名方的随意性。文章正是在这一方面进行了研究。1995年,Delos和QuisquateHM首次提出了一个签名方案;在该方案中,签名者能且只能签发固定数目的消息,而且不能控制多重签名次数。文章建立在RSA安全的基础上,设计了控制签名数目的方案。该方案允许签名者签发任意数次,但可控制其签名数次;同时设计了一种能够控制多重签名能力的方案。该新方案在实际中有着十分广阔的应用。 相似文献
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提出了一个具有消息恢复的共享验证代理签名方案。在该方案中,把签名的验证权让[n]个验证人分享,使得指定验证组中的[t]个或更多验证人合作能从签名中恢复消息并能验证签名的有效性。该方案满足代理签名方案的安全要求,传送签名时无需传送消息,和其他代理签名方案相比,降低了通信开销;同时也降低了验证人欺骗的风险,万一遇到验证人欺骗,该方案能准确地检查出哪一个验证人在欺骗。 相似文献
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具有前向安全性质的指定验证人代理签名方案 总被引:1,自引:0,他引:1
由于已有的指定验证人代理签名方案都不具有前向安全的性质,基于有限域上离散对数难解问题和强RSA假设,应用前向安全理论和指定验证人代理签名方案思想,提出了一种具有前向安全特性的指定验证人代理签名方案。在该方案中,代理签名具有前向安全性,即使代理签名人当前时间段的代理签名密钥被泄漏,敌手也不能伪造此时段之前的签名,以前所产生的代理签名依然有效。 相似文献
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在一般的数字签名中,拥有签名者公钥的任何人都可以验证该签名的有效性;而强指定验证者签名是由签名者指定一个验证者,在签名验证阶段,只有这个指定验证者可以验证该签名的有效性,其他人都不能验证该签名。这是因为在签名的验证阶段必须用到指定验证者的私钥。基于这个性质,强指定验证者签名被广泛应用于电子商务、网上投标、电子选举中。基于双线性对提出了一个新的基于身份的强指定验证者签名方案,并基于GBDH困难问题假设,采用密码学上安全性分析的方法,证明了该方案在适应性选择消息和选择身份攻击下是不可伪造的。最后,分析了方案的计算成本,结果表明该方案具有较高的效率。 相似文献
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由于已有的指定验证人代理签名方案都是基于公钥密码体制和身份密码体制的,应用自认证公钥技术和指定验证人代理签名思想,提出了一种新的使用自认证公钥的指定验证人代理签名方案。该方案具有以下特点:在传送签名时,没有必要传送消息,因为指定验证人能从签名中正确恢复出消息;在验证签名有效性的同时,也验证了公钥的真实性,这些验证能在逻辑单步内完成;在验证公钥真实性时,不需要额外的证书。和已有方案相比,新方案具有通信代价低、计算量少的优点,是一种更高效的指定验证人代理签名方案。 相似文献
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S. Shaw 《Journal of Computer Assisted Learning》1993,9(2):93-99
Abstract This paper describes an approach to the design of interactive multimedia materials being developed in a European Community project. The developmental process is seen as a dialogue between technologists and teachers. This dialogue is often problematic because of the differences in training, experience and culture between them. Conditions needed for fruitful dialogue are described and the generic model for learning design used in the project is explained. 相似文献
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European Community policy and the market 总被引:1,自引:0,他引:1
C. Lloyd 《Journal of Computer Assisted Learning》1993,9(2):86-91
Abstract This paper starts with some reflections on the policy considerations and priorities which are shaping European Commission (EC) research programmes. Then it attempts to position the current projects which seek to capitalise on information and communications technologies for learning in relation to these priorities and the apparent realities of the marketplace. It concludes that while there are grounds to be optimistic about the contribution EC programmes can make to the efficiency and standard of education and training, they are still too technology driven. 相似文献
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融合集成方法已经广泛应用在模式识别领域,然而一些基分类器实时性能稳定性较差,导致多分类器融合性能差,针对上述问题本文提出了一种新的基于多分类器的子融合集成分类器系统。该方法考虑在度量层融合层次之上通过对各类基多分类器进行动态选择,票数最多的类别作为融合系统中对特征向量识别的类别,构成一种新的自适应子融合集成分类器方法。实验表明,该方法比传统的分类器以及分类融合方法识别准确率明显更高,具有更好的鲁棒性。 相似文献
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Wayne O’Brien Author Vitae 《Journal of Systems and Software》2008,81(11):1997-2013
Development of software intensive systems (systems) in practice involves a series of self-contained phases for the lifecycle of a system. Semantic and temporal gaps, which occur among phases and among developer disciplines within and across phases, hinder the ongoing development of a system because of the interdependencies among phases and among disciplines. Such gaps are magnified among systems that are developed at different times by different development teams, which may limit reuse of artifacts of systems development and interoperability among the systems. This article discusses such gaps and a systems development process for avoiding them. 相似文献
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This paper presents control charts models and the necessary simulation software for the location of economic values of the control parameters. The simulation program is written in FORTRAN, requires only 10K of main storage, and can run on most mini and micro computers. Two models are presented - one describes the process when it is operating at full capacity and the other when the process is operating under capacity. The models allow the product quality to deteriorate to a further level before an existing out-of-control state is detected, and they can also be used in situations where no prior knowledge exists of the out-of-control causes and the resulting proportion defectives. 相似文献
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Going through a few examples of robot artists who are recognized worldwide, we try to analyze the deepest meaning of what
is called “robot art” and the related art field definition. We also try to highlight its well-marked borders, such as kinetic
sculptures, kinetic art, cyber art, and cyberpunk. A brief excursion into the importance of the context, the message, and
its semiotics is also provided, case by case, together with a few hints on the history of this discipline in the light of
an artistic perspective. Therefore, the aim of this article is to try to summarize the main characteristics that might classify
robot art as a unique and innovative discipline, and to track down some of the principles by which a robotic artifact can
or cannot be considered an art piece in terms of social, cultural, and strictly artistic interest.
This work was presented in part at the 13th International Symposium on Artificial Life and Robotics, Oita, Japan, January
31–February 2, 2008 相似文献
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张涛 《计算机测量与控制》2015,23(1):86-89
为了设计一种具有低成本、低功耗、易操作、功能强且可靠性高的煤矿井下安全分站,针对煤矿安全生产实际,文章提出了采用MCS-51系列单片机为核心、具有CAN总线通信接口的煤矿井下安全监控分站的设计方案;首先给出煤矿井下安全监控分站的整体构架设计,然后着重阐述模拟量输入信号处理系统的设计过程,最后说明单片机最小系统及其键盘、显示、报警、通信等各个组成部分的设计;为验证设计方案的可行性与有效性,使用Proteus软件对设计内容进行仿真验证,设计的煤矿井下安全监控分站具有瓦斯、温度等模拟量参数超标报警功能和电机开停、风门开闭等开关量指示功能;仿真结果表明:设计的煤矿井下安全监控分站具有一定的实际应用价值. 相似文献
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Recent years have seen rapid advances in various grid-related technologies, middleware, and applications. The GCC conference has become one of the largest scientific events worldwide in grid and cooperative computing. The 6th international conference on grid and cooperative computing (GCC2007) Sponsored by China Computer Federation (CCF),Institute of Computing Technology, Chinese Academy of Sciences (ICT) and Xinjiang University ,and in Cooperation with IEEE Computer Soceity ,is to be held from August 16 to 18, 2007 in Urumchi, Xinjiang, China. 相似文献
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David Poole 《Computational Intelligence》1989,5(2):97-110
Although there are many arguments that logic is an appropriate tool for artificial intelligence, there has been a perceived problem with the monotonicity of classical logic. This paper elaborates on the idea that reasoning should be viewed as theory formation where logic tells us the consequences of our assumptions. The two activities of predicting what is expected to be true and explaining observations are considered in a simple theory formation framework. Properties of each activity are discussed, along with a number of proposals as to what should be predicted or accepted as reasonable explanations. An architecture is proposed to combine explanation and prediction into one coherent framework. Algorithms used to implement the system as well as examples from a running implementation are given. 相似文献
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Watts S. Humphrey 《Annals of Software Engineering》2002,14(1-4):39-72
This paper provides the author's personal views and perspectives on software process improvement. Starting with his first work on technology assessment in IBM over 20 years ago, Watts Humphrey describes the process improvement work he has been directly involved in. This includes the development of the early process assessment methods, the original design of the CMM, and the introduction of the Personal Software Process (PSP)SM and Team Software Process (TSP){SM}. In addition to describing the original motivation for this work, the author also reviews many of the problems he and his associates encountered and why they solved them the way they did. He also comments on the outstanding issues and likely directions for future work. Finally, this work has built on the experiences and contributions of many people. Mr. Humphrey only describes work that he was personally involved in and he names many of the key contributors. However, so many people have been involved in this work that a full list of the important participants would be impractical. 相似文献