航天产品多源可靠性信息的收集与整理--建立可靠性信息数据库

航天产品可靠性信息的来源多样，可靠性信息的时间性、随机性、有价性、时效性和可追溯性等特征，决定了可靠性数据收集应满足真实性、连续性、完整性等基本要求。同时，对多源信息的收集应遵循先进行需求分析，再确定数据收集点并制定数据收集表格的程度进行。给出了信息的适用性准则和信息分类的三维模型。最后结合具体型号航天产品的可靠性工作的要求，给出了可靠性信息数据库系统的整体方案设计。     

Logistic映射及其混沌序列特性分析

提出了一种基于频谱特征分析Logistic映射工作状态的方法.首先,对典型Logistic迭代映射函数,在给定初值的情况下随参数μ变化得到不同的数值分布序列图和分岔图;其次,通过傅立叶变换得到Logistic映射的频谱特性,从频域弥补了时域分析中无法观测到的Logistic映射混沌特性;最后,通过对比分析表明Logistic映射的类随机性适合应用于保密通信领域.     

Data Security Model for Cloud Computing

From the perspective of data security, which has always been an important aspect of quality of service, cloud computing focuses a new challenging security threats. Therefore, a data security model must solve the most challenges of cloud computing security. The proposed data security model provides a single default gateway as a platform. It used to secure sensitive user data across multiple public and private cloud applications, including Salesforce, Chatter, Gmail, and Amazon Web Services, without influencing functionality or performance. Default gateway platform encrypts sensitive data automatically in a real time before sending to the cloud storage without breaking cloud application. It did not effect on user functionality and visibility. If an unauthorized person gets data from cloud storage, he only sees encrypted data. If authorized person accesses successfully in his cloud, the data is decrypted in real time for your use. The default gateway platform must contain strong and fast encryption algorithm, file integrity, malware detection, firewall, tokenization and more. This paper interested about authentication, stronger and faster encryption algorithm, and file integrity.     

基于云模型的科技奖励评审模型研究

云模型是实现定性概念与定量表示之间不确定性转换的模型,它把模糊性和随机性有机结合起来。本文提出了一种基于云模型的科技奖励评审模型,利用云模型客观描述项目的评分在各属性下的分布情况,通过计算云模型参数来确定云模型数字特征图或云滴分布情况,并以此确定最后等级。结果表明,该模型能够解决项目单一属性分类及非共识等问题,同时能够客观地反映出项目实际综合评审结果,从而使得评审更加公平合理。     

Logistic混沌网络会议加密系统的设计

文章采用Logistic混沌序列对实时视频传输系统进行数据的分块加／解密,并从算法的安全性、效率等方面进行了性能分析,该算法具有良好的实时性、快速性和易实施性,可以有效地防止敏感信息被轻易的窃取、篡改和传播,有效保障网络视频传输的流畅性及安全性。     

混沌密码系统弱密钥随机性分析

弱密钥问题是混沌密码系统设计中的关键问题,已有研究主要从混沌序列退化角度进行分析.然而,本文指出保证混沌序列不退化的密钥参数仍可能构成混沌密码的弱密钥.本文提出以混沌密码序列随机性作为评价标准,应用严格的统计检验方法对混沌密码的弱密钥进行检测.进一步,对一类混沌密码系统进行了弱密钥研究,检测出了该系统大量未被发现的弱密钥.这确证了所提出方法的有效性.另一方面,虽然已有较多研究采用统计检验对混沌比特序列进行测试,但将统计检验用于分析混沌密码弱密钥或弱序列的研究还很少见.本文给出的统计检验弱序列分析,对当前混沌密码统计检验研究是一个很好的补充.     

Comparing notions of randomness

It is an open problem in the area of effective (algorithmic) randomness whether Kolmogorov-Loveland randomness coincides with Martin-Löf randomness. Joe Miller and André Nies suggested some variations of Kolmogorov-Loveland randomness to approach this problem and to provide a partial solution. We show that their proposed notion of injective randomness is still weaker than Martin-Löf randomness. Since in this proof some of the ideas we use are clearer, we also show the weaker theorem that permutation randomness is weaker than Martin-Löf randomness.     

泥沙起动流速的随机分析

泥沙起动流速是河流泥沙动力学基本概念之一,对泥沙运动及河床冲淤变形研究有着重要意义.天然河流中的泥沙运动多处在紊流状态下,其影响因素极其复杂,具有显著的随机性.本文在总结前人研究成果的基础上,从流体力学层面论述了以作用于泥沙颗粒上的局部流速表示泥沙起动流速的合理性,进一步拓展分析,指出了以往公式的不足,给出了以局部点流速表示的包括散粒体与粘性颗粒在内的全沙起动流速公式,继而与各家公式作了对比;基于随机理论,给出了泥沙普遍动、少量动、个别动的判据,并将均值流速概率化,扩展了泥沙颗粒起动的范围与认知.     

一种改善Tent混沌序列随机性的方法

Tent混沌映射具有良好的遍历性和均匀性,但其随机性不理想。为此,提出一种改善Tent混沌序列随机性的方法。通过将Tent混沌映射变换为分段混沌映射,增大Lyapunov指数,改善相关系数和功率谱特性。对序列进行NIST随机性测试,结果表明,该分段Tent映射的序列具有较好的随机性,适用于通信与信息安全领域。     

Probabilistic Type-2 Operators and “Almost”-Classes

We define and examine several probabilistic operators ranging over sets (i.e., operators of type 2), among them the formerly studied ALMOST-operator. We compare their power and prove that they all coincide for a wide variety of classes. As a consequence, we characterize the ALMOST-operator which ranges over infinite objects (sets) by a bounded-error probabilistic operator which ranges over strings, i.e., finite objects. This leads to a number of consequences about complexity classes of current interest. As applications, we obtain (a) a criterion for measure 1 inclusions of complexity classes, (b) a criterion for inclusions of complexity classes relative to a random oracle, (c) a new upper time bound for ALMOST-PSPACE, and (d) a characterization of ALMOST-PSPACE in terms of checking stack automata. Finally, a connection between the power of ALMOST-PSPACE and that of probabilistic circuits is given. Received: 16 April 1996