电力系统下的轻量级自适应认证系统

电力物联终端种类繁多,绝大多数处于资源受限的状态下,在实际应用上存在安全需求。本文设计了一种基于LBlock加密算法的挑战应答协议和基于国家商用密码认证方案的轻量级自适应身份认证系统。系统通过树莓派仿真资源受限的电力物联终端测试身份认证以及密钥协商效率与安全性。测试结果表明,该轻量级自适应认证系统可以实现边缘物联代理与各类受限电力物联终端的双向身份认证,有效保证了电力系统自适应认证的需求。     

基于Hyperledger的电力物联网分布式认证研究

随着能源互联网的发展和"云、大、物、移"战略的实施,传统的电力物联网终端集中式接入认证方式难以应对泛在普适的应用需求。基于联盟区块链的超级账本技术,研究了电力物联网终端分布式接入认证技术,将安全多方计算中密钥共享和分配协议与超级账本共识算法相结合,提出了一种有效的电力物联网终端接入认证方案。仿真结果表明,所提方案在认证时间和资源消耗等方面具有优势。     

基于区块链的电力物联网接入认证技术研究

随着信息通信技术的发展和"云、大、物、移"战略的实施,电力物联网已为电网发输变配用电等环节提供重要支撑,然而目前集中式的接入认证方式给认证中心带来了巨大的计算和通信压力,特别是大规模并发接入和移动接入为系统认证效率带来严重影响。利用区块链技术去中心化、不可否认的特性,结合电力系统特点,提出了适用于电力物联网的分布式认证方案,方案结合Shamir门限秘密共享机制实现了一种PBFT共识机制,已经合法接入的终端组成认证组,发起对新入终端的分布式认证,并通过区块链分布式账本进行记录。实验表明,该方案可有效提高电力物联网终端并发接入效率。     

基于零信任框架的泛在电力物联网安全防护研究

建设泛在电力物联网是充分应用"大云物移智"等现代化信息技术,实现电力系统各个环节的万物互联、人机交互.在这种新场景下,身份认证、数据安全、信息交互等网络安全问题迫切需要解决,本文从零信任框架出发,构建泛在电力物联网安全防护方案,重点从身份认证、动态授权、监测审计三个方面提出防护建议,打破传统以边界防护为基础的网络安全框架,为泛在电力物联网安全防护提供新思路、新方法,以适应泛在电力物联网的业务发展需求.     

泛在电力物联网可信安全接入方案

为全面提高全业务泛在电力物联网安全综合防御能力,解决目前全业务泛在电力物联网安全防护指导和终端认证机制的缺失和不足,本文提出一种泛在电力物联网可信安全接入方案。首先给电力物联网终端层设备确定一个唯一标识的指纹信息;然后结合该指纹信息,采用身份标识密码技术实现终端层设备的接入认证,阻断非法终端的接入;最后设计合法终端的身份信息安全传递机制,根据身份信息对合法终端的异常行为进行溯源。     

基于政务物联数据专网的物联网安全技术保障框架研究

物联网在安防、电力、环保等众多领域得到广泛应用,物联网应用面临的安全威胁日益凸显,建设、运营单位普遍对物联网安全保障认识不足。文章针对基于北京市政务物联数据专网的物联网应用,从网络边界安全、感知网安全、物联应用安全等方面探讨了北京市政务物联数据专网的安全威胁,并建立了安全技术保障框架,为政务物联网应用的安全等级保护建设及测评工作奠定了良好的基础。     

物联网中基于聚合签名的认证方案研究

随着物联网用户终端数量的增长,现有的接入认证方案出现系统资源消耗大和信令拥塞问题。为了解决认证过程中的这些问题,提高认证效率,本文将安全高效的基于身份的聚合签名方案引入物联网终端与网络之间的认证,可以实现若干的物联网终端只需生成一个签名,就可以完成多个终端的认证。本文提出的方案在保证安全的同时提高了认证的效率,也避免了基于公钥证书的认证方案中证书管理的困难。     

基于区块链技术的电力物联网终端安全认证系统应用研究

电网状态全感知的目标意味着物联网技术在电网的广泛应用,大量物联网终端通过传感技术、通信技术和计算机技术接入网络。电力物联网终端分布呈现数量大、地域广、采集数据复杂的特点,容易被攻击者突破和入侵,而且传统的中心化认证存在单点失败、性能瓶颈等问题。本文基于区块链技术,研发并应用了基于终端标识符的DID数字身份、区块链多源适配的DID解析器、基于终端凭证信息的零知识证明、基于机器学习算法的设备管理等技术,设计出了一种基于区块链的电力物联网终端安全认证系统。该系统在电网内成功应用,实现了物联网设备接入认证的去中心化,降低了设备接入的网络安全风险,减少了中心化基础设施建设和维护的成本,提高了运维人员的工作效率。     

面向物联网的可信设备标识及安全更新方案

物联网终端规模巨大、设备间能力差异大，存在资源受限、安全防护能力较弱、部署环境不安全等问题，容易被攻击者利用安全漏洞入侵，物联网终端安全成为当前物联网安全的薄弱环节。基于可信计算技术，面向物联网资源受限终端场景，提出了以物理不可克隆函数和设备标识符组合技术为基础的轻量化密码应用方案，并设计了信任根、设备标识、设备认证和安全代码更新关键机制，可为后续物联网终端安全防护技术研究及工程实践提供参考。     

电力物联网信息安全防护技术研究

介绍了电力物联网在配电网的应用场景,总结了我国电力物联网信息安全防护的发展历程,分析了当前电力物联网信息安全应用中存在的主要问题和解决电力物联网信息安全的关键技术,最后提出了电力物联网终端本体的信息安全防护的四道防线模型和实践。     

European Community policy and the market

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.     

一种自适应子融合集成多分类器方法

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。     

Explanation and prediction: an architecture for default and abductive reasoning

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.     

Three Process Perspectives: Organizations, Teams, and People

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.     

基于复小波噪声方差显著修正的SAR图像去噪

提出了一种基于复小波域统计建模与噪声方差估计显著性修正相结合的合成孔径雷达(Synthetic Aperture Radar,SAR)图像斑点噪声滤波方法。该方法首先通过对数变换将乘性噪声模型转化为加性噪声模型,然后对变换后的图像进行双树复小波变换(Dualtree Complex Wavelet Transform,DCWT),并对复数小波系数的统计分布进行建模。在此先验分布的基础上,通过运用贝叶斯估计方法从含噪系数中恢复原始系数,达到滤除噪声的目的。实验结果表明该方法在去除噪声的同时保留了图像的细节信息,取得了很好的降噪效果。     

How do children do mathematics with LOGO?

Abstract  This paper considers some results of a study designed to investigate the kinds of mathematical activity undertaken by children (aged between 8 and 11) as they learned to program in LOGO. A model of learning modes is proposed, which attempts to describe the ways in which children used and acquired understanding of the programming/mathematical concepts involved. The remainder of the paper is concerned with discussing the validity and limitations of the model, and its implications for further research and curriculum development.     

Editorial: Special issue on recent advances in hybrid control theory and applications

正The demands of a rapidly advancing technology for faster and more accurate controllers have always had a strong influence on the progress of automatic control theory.In recent years control problems have been arising with increasing frequency in widely different areas,which cannot be addressed using conventional control techniques.The principal reason for this is the fact that a highly competitive economy is forcing systems to operate in regimes where     

Information for Authors

正Aim The Journals of Zhejiang University-SCIENCE(A/B/C)areedited by the international board of distinguished Chinese andforeign scientists,and are aimed to present the latest devel-opments and achievements in scientific research in China andoverseas to the world’s scientific circles,especially to stimulateand promote academic exchange between Chinese and for-eign scientists everywhere.     

Enhancing a leaf radiative transfer model to estimate concentrations and in vivo specific absorption coefficients of total carotenoids and chlorophylls a and b from single-needle reflectance and transmittance

The relative concentrations of different pigments within a leaf have significant physiological and spectral consequences. Photosynthesis, light use efficiency, mass and energy exchange, and stress response are dependent on relationships among an ensemble of pigments. This ensemble also determines the visible characteristics of a leaf, which can be measured remotely and used to quantify leaf biochemistry and structure. But current remote sensing approaches are limited in their ability to resolve individual pigments. This paper focuses on the incorporation of three pigments—chlorophyll a, chlorophyll b, and total carotenoids—into the LIBERTY leaf radiative transfer model to better understand relationships between leaf biochemical, biophysical, and spectral properties.Pinus ponderosa and Pinus jeffreyi needles were collected from three sites in the California Sierra Nevada. Hemispheric single-leaf visible reflectance and transmittance and concentrations of chlorophylls a and b and total carotenoids of fresh needles were measured. These data were input to the enhanced LIBERTY model to estimate optical and biochemical properties of pine needles. The enhanced model successfully estimated reflectance (RMSE = 0.0255, BIAS = 0.00477, RMS%E = 16.7%), had variable success estimating transmittance (RMSE = 0.0442, BIAS = 0.0294, RMS%E = 181%), and generated very good estimates of carotenoid concentrations (RMSE = 2.48 µg/cm², BIAS = 0.143 µg/cm², RMS%E = 20.4%), good estimates of chlorophyll a concentrations (RMSE = 10.7 µg/cm², BIAS = − 0.992 µg/cm², RMS%E = 21.1%), and fair estimates of chlorophyll b concentrations (RMSE = 7.49 µg/cm², BIAS = − 2.12 µg/cm², RMS%E = 43.7%). Overall root mean squared errors of reflectance, transmittance, and pigment concentration estimates were lower for the three-pigment model than for the single-pigment model. The algorithm to estimate three in vivo specific absorption coefficients is robust, although estimated values are distorted by inconsistencies in model biophysics. The capacity to invert the model from single-leaf reflectance and transmittance was added to the model so it could be coupled with vegetation canopy models to estimate canopy biochemistry from remotely sensed data.     

Mr. Twinn’s bombes

This article discusses the history and design of the special versions of the bombe key-finding machines used by Britain’s Government Code & Cypher School (GC&CS) during World War II to attack the Enigma traffic of the Abwehr (the German military intelligence service). These special bombes were based on the design of their more numerous counterparts used against the traffic of the German armed services, but differed from them in important ways that highlight the adaptability of the British bombe design, and the power and flexibility of the diagonal board. Also discussed are the changes in the Abwehr indicating system that drove the development of these machines, the ingenious ways in which they were used, and some related developments involving the bombes used by the U.S. Navy’s cryptanalytic unit (OP-20-G).