关系模式关键字的一个求解算法

本文给出了关系数据库模式中求解关键字的一个算法。算法很简洁并且对于[1]定义的一大类问题,执行时间是多项式级的。     

Sending-or-Not-Sending Twin-Field Quantum Key Distribution with a Passive Decoy-State Method

Twin-field quantum key distribution (TF-QKD) has attracted considerable attention because it can exceed the basic rate-distance limit without quantum repeaters. Its variant protocol, sending or not-sending quantum key distribution (SNS-QKD), not only fixes the security vulnerability of TF-QKD, but also can tolerate large misalignment errors. However, the current SNS-QKD protocol is based on the active decoy-state method, which may lead to side channel information leakage when multiple light intensities are modulated in practice. In this work, we propose a passive decoy-state SNS-QKD protocol to further enhance the security of SNS-QKD. Numerical simulation results show that the protocol not only improves the security in source, but also retains the advantages of tolerating large misalignment errors. Therefore, it may provide further guidance for the practical application of SNS-QKD.     

KEADA: Identifying Key Classes in Software Systems Using Dynamic Analysis and Entropy-Based Metrics

Software maintenance is indispensable in the software development process. Developers need to spend a lot of time and energy to understand the software when maintaining the software, which increases the difficulty of software maintenance. It is a feasible method to understand the software through the key classes of the software. Identifying the key classes of the software can help developers understand the software more quickly. Existing techniques on key class identification mainly use static analysis techniques to extract software structure information. Such structure information may contain redundant relationships that may not exist when the software runs and ignores the actual interaction times between classes. In this paper, we propose an approach based on dynamic analysis and entropy-based metrics to identify key classes in the Java GUI software system, called KEADA (identifying KEy clAsses based on Dynamic Analysis and entropy-based metrics). First, KEADA extracts software structure information by recording the calling relationship between classes during the software running process; such structure information takes into account the actual interaction of classes. Second, KEADA represents the structure information as a weighted directed network and further calculates the importance of each node using an entropy-based metric OSE (One-order Structural Entropy). Third, KEADA ranks classes in descending order according to their OSE values and selects a small number of classes as the key class candidates. In order to verify the effectiveness of our approach, we conducted experiments on three Java GUI software systems and compared them with seven state-of-the-art approaches. We used the Friedman test to evaluate all approaches, and the results demonstrate that our approach performs best in all software systems.     

基于改进GMM与帧差法的运动棉杂率分析算法研究

针对清梳棉流程中产出棉含杂高、质量差的问题,结合改进高斯混合模型(Gaussian mixed model,GMM)与帧差法,提出一种局部运动棉杂率控制优化方法。首先针对清棉机除杂原理及棉杂特性进行分析;其次通过提取视频关键帧并改进GMM与帧差法对图像序列“与”运算实现目标的精确提取,进而通过设计GMM分类器获得棉杂率并进行分析;最后与传统的检测算法作对比验证。实验表明,改进后的算法在有效性以及实用性方面优于传统算法。同时,通过引入闭环控制能满足工业高精度、实时性的需求。     

Propolis Contra Pharmacological Interventions in Bees

In addition to wax, propolis is a mixture of resins, terpenes, and etheric and aromatic oils. This composition supports its very strong biochemical activity that affects bee health. Bee colonies are externally exposed to the activity of other different pharmacologically active substances and toxic agents used in beekeeping procedures, veterinary interventions, and the environment. Even if free form common diseases, they may suffer from parasites or toxins. In any such case the abundance and variety of honeyflow, besides proper therapy, is crucial for the maintenance of bee health. Propolis itself cannot be considered as food but can be considered as micro-nutrients for bees. This is due to the fact that some of its compounds may penetrate different bee products, and this way be consumed by bees and their larvae, while stored in the hive. This perspective shows propolis as natural agent reducing the toxicity of pyrethroid acaricides, stimulating production of detoxification enzymes, enhancing the action of antibiotics, and increasing expression of genes that encode proteins responsible for detoxication. The aim of this review is to summarize current data on the possible impact on veterinary public health of the introduction into propolis of residues of pharmacological agents approved in the EU for use in the treatment of bee colonies and their environment.     

科技博物馆公共空间利用初探

在科技博物馆界,利用公共空间进行展览教育活动已经成为一种发展趋势。本文在讨论科技博物馆公共空间的定义及功能的基础上,结合国内外实例归纳了依据空间结构编制情节和设立展示内容的方法。公共空间是人与环境、人与人在特定的环境中的交流场所,空间的情节决定了此种交流的内涵。编制公共空间的情节是科技博物馆公共空间设计的主要任务。本文认为有意义的主题、主题的展开方式、能够表达主题的展品、烘托主题的场景、情节或场景的顺序变化等五项元素是公共空间情节编制的主要内容。并据此总结了公共空间展示设计的基本思路和若干展示设计原则。     

基于分段Logistic映射的二维耦合映像格子模型的密码学相关特性分析

将分段Logistic映射作为局部混沌映射,引入到二维耦合映像格子模型中,构造了一种具有复杂动力学特性的混沌模型.从密码学应用出发,深入分析了该模型中参数设置对Lyapunov指数、分岔、遍历区间和概率密度分布等特性的影响.分析的结果为将该模型应用于保密通信的参数设置提供了理论依据.在此基础上,通过引入状态值偏移量,解决了该模型状态值概率密度分布不均的问题,研究结果表明本文模型具有良好的性能,为将其应用于混沌保密通信方案设计提供了基础与条件.     

美国米勒公民科学素养测评指标体系的形成与演变

美国学者J.D.米勒教授首创了公民科学素养测评指标体系,为科学评估公众科学素养水平提供了有效工具.本文论述了米勒公民科学素养测评指标体系的产生背景、形成过程与演变历程及其国际应用,并揭示了其对我国当前公民科学素质测评指标建设所具有的借鉴意义.     

郡县制国家现代化：中央政府如何扩大公共事务治理职能

郡县制国家的传统职能是“管人”,但是在当代,为了适应现代世界,需要加强和完善“管事”的职能。然而,加强“管事”的职能遇到的一大障碍,是“管事”与“管人”通常难以分开,带来管事与管人的冲突。在全国性公共事务上,面对管事与管人的冲突,郡县制国家的一种改革方向,即建立中央统一管理与地方属地管理相结合的体制,既扩大中央政府的治理职能,同时又发挥纵向约束机制的作用,从而能改善全国性公共事务治理。此种中央统一管理与地方属地管理相结合的体制,通常不是中央政府事先设计出来的,而是在改革过程中,经由中央政府与地方政府的策略性互动过程,逐渐建立起来的。因此,郡县制国家蕴含着一种潜力,即在公共事务治理上,包括地方公共事务和全国性公共事务,可以引入和发挥“纵向约束机制”的作用,使得国家既保持“管人”的基本体制不变,又能提高治理能力。     

Unidimensional continuous-variable quantum key distribution with discrete modulation

In this paper, we proposed an unidimensional continuous-variable quantum key distribution (CV-QKD) protocol with discrete modulation, which waives the necessity in one of the quadrature modulations and further simplified the implementation of the CV-QKD protocol. On the basis of the Heisenberg uncertainty relation, we analyze the boundary between the unphysical and physical region. Besides, we utilize a novel proof approach to achieve a lower bound valid of transmission distance. This scheme shows an available method to further simplified the implementation of the QKD.