具有小规模公开参数的适应安全的非零内积加密方案

内积加密是一种支持内积形式的函数加密,已有内积加密方案的公开参数规模较大,为解决该问题,该文基于素数阶熵扩张引理,利用双对偶向量空间(DPVS)技术,提出一个公开参数规模较小的具有适应安全性的内积加密方案。在方案的私钥生成算法中,将用户的属性向量的分量与主私钥向量结合,生成一个可与熵扩张引理中密钥分量结合的向量;在方案的加密算法中,将内积向量的每一分量与熵扩张引理中的部分密文分量结合。在素数阶熵扩张引理和${\rm{MDDH}}_{k, k + 1}^n$困难假设成立条件下,证明了方案具有适应安全性。该文方案公开参数仅有10个群元素,与现有内积加密方案相比,公开参数规模最小。     

国外“遗产化”研究引介——对国内遗产认知和遗产实践的启示

"申遗热"和"遗产热"的社会现状表明我国已经进入了"遗产化"时代,本文侧重介绍国外遗产化的研究历史,包括"遗产化"的产生和概念、"遗产化"的反思批判、新世纪"遗产化"的再认知,进而分析我国当前"遗产化"进程中存在的问题,并结合国外"遗产化"的经验教训,提出对当前遗产实践和遗产认知的几点启示。     

一次变色龙哈希函数及其在可修正区块链中的应用

提出了称作一次变色龙哈希函数的新密码学原语:同一哈希值的2个原像(一次碰撞)不会暴露任何陷门信息,而同一哈希值的3个原像(二次碰撞)则会暴露部分陷门信息,但足以导致严重的安全危害.基于经典的RSA困难问题构造了简单高效的一次变色龙哈希函数方案,并在随机预言模型下证明了其安全性.应用该一次变色龙哈希函数方案,进一步高效实现了对每个区块仅允许至多一次修正的可修正区块链,而任何区块的二次修改都将导致区块链崩溃的惩罚.对区块链进行有效治理是网络空间安全治理的关键领域,而可修正区块链则构成了区块链监管和治理的最核心技术.所提出的可修正区块链方案具有高效和修正权限契合实际需求的两大特点,有望为区块链监管(尤其是链上有害数据的事后治理)提供有力的技术参考.     

“饥饿”反应器中自由基聚合动力学(Ⅰ)──关于长链假定适用性的讨论

在建立自由基聚合动力学模型时，由于聚合度很大，通常假定聚合速率等于链增长速率，认为用于链引发所消耗的单体量极少，将其忽略不计，即所谓的长链假定．本文对这一假定进行了详尽的分析，通过计算表明：在高温或／和高引发剂浓度下，特别是在“饥饿”反应器中，长链假定不再适用，建立更为精确的聚合动力学模型时，须考虑长链假定适用性．     

Morton Deutsch.

Morton Deutsch is recognized for his achievements in psychology. This article provides a citation explaining his accomplishments, a biography and a selected bibliography. The citation is as follows: "For rigorous scientific study of significant social problems. Beginning with groundbreaking inquiries into cooperative and competitive relationships, his work produced major advances in society's understanding of racial prejudice, individual conformity, and social justice. Through sustained, systematic investigation, he formulated a unified theory containing principles applicable to intrapersonal and international conflicts as well as interpersonal ones. His methodological innovations made possible controlled study of complex social phenomena, including trust, suspicion, promises, and threats. An inspiring mentor and colleague, he is a model citizen-scientist, devoting selfless effort to improving society through the humane application of scientifically derived knowledge." (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Modeling currency exchange rate time series

Previous studies have shown that a random walk model is an appropriate time series model for explaining exchange rate time series. This analysis is based on the assumption that the variance of an exchange rate time series is homogeneous with respect to time. This paper shows that this assumption may be violated for exchange rate time series. The monthly exchange rate of German Deutschemark per U.S. dollar is considered. The data ranges from March 1973 to December 1984. The starting point roughly coincides with the beginning of the floating rate regime. It is seen that a non-linear model would be more appropriate than a linear model for explaining this exchange rate time series.     

天津市工业自动化技术发展战略研究

简要地介绍了自动化技术的服务原理,并详细地分析天津市工业自动化技术现状,对各类技术发展的可能性与需要性进行评价,提出天津市工业自动化技术发展的设想和建议。     

三角形钢屋架力学计算模型的研究

对三角形钢屋架的杆件类型及立柱抗侧刚度因素对屋架的内力影响进行了研究．由于三角形屋架的弦杆制作通常采用整根杆件制作,与腹杆用节点板连接,并支撑于钢立柱上,因此弦杆杆件类型及立柱侧移刚度对屋架内力有一定影响．本文利用MIDAS对某仓库工程三角形屋架进行了4种力学模拟计算,通过对比：设计时,三角形钢屋架的弦杆按梁单元是必要的,同时不考虑立柱抗侧刚度对屋架内力影响．对此类屋架设计本文提出了明确的计算方法,具有较高的实用价值．     

Implicit Epistemic Aspects of Constructive Logic

In the present paper I wish to regard constructivelogic as a self-contained system for the treatment ofepistemological issues; the explanations of theconstructivist logical notions are cast in anepistemological mold already from the outset. Thediscussion offered here intends to make explicit thisimplicit epistemic character of constructivism.Particular attention will be given to the intendedinterpretation laid down by Heyting. This interpretation, especially as refined in the type-theoretical work of Per Martin-Löf, puts thesystem on par with the early efforts of Frege andWhitehead-Russell. This quite recent work, however,has proved valuable not only in the philosophy andfoundations of mathematics, but has also foundpractical application in computer science, where thelanguage of constructivism serves as an implementableprogramming language, and within the philosophy oflanguage.\footnote{Nordstr\"{o}m et al. (1990) give an overview of the work in computerscience, whereas Ranta (1995) provides an impressiveconstructivist alternative to Montague Grammar usingthe richer type structure of Martin-L\"{o}f in placeof the simple classical type theory of Church.} Mypresentation will be carried out through a contrastwith standard metamathematical work.\footnote{Troelstra and van Dalen (1988) give an encyclopedictreatment of the metamathematics of constructivism.}In the course of the development I have occasion tooffer some novel considerations (in Sections~6 and 8) on thenature of proof and inference(-acts).     

群盲签名的通用可组合性研究

协议的UC安全性可以确保它在并发环境下运行的安全性。本文在UC框架下提出了一个群盲签名的理想函数,并在离散对数假设下构造了一个具有UC安全的群盲签名协议。然后,分析了此协议的安全性并详细地证明了群盲签名可以安全实现理想函数。