目录服务技术及其在NOS中的应用

目录服务能构建更为安全有效,易于管理的网络应用于平台,该项技术已越来越受到业界的重视。本文首先介绍了目录服务的基本概念和它的协议基础,然后重点介绍了两 网络操作系统中的目录服务技术：Novell的NDS和Microsoft的AD,并分析了两者的异同。     

基于LDAP服务器的模式管理系统研究与设计

以一个电子政务研究中的基于LDAP服务器的模式管理研究为背景,通过对LDAP服务器的特性和所需安全功能的研究和分析,给出了以LDAP服务器为基础和以安全服务系统为数据交换平台的模式管理系统的开发设计方案,突破LDAP服务器自身提供的安全限制,同时也体现了目录和文件管理的便捷性。     

基于CIM的机群系统资源信息模型

通过对CIM进行面向机群系统的扩展和裁减,设计了一种基于CIM的机群系统资源信息模型,并且在Linux上用LDAP实现了这个信息模型,为表示机群系统的资源信息提供了一种统一的方式,为大规模机群系统的资源信息服务、高性能计算服务和其他相关应用打下了良好的基础。     

基于PUF的轻量级RFID安全认证协议

针对现有的RFID(Radio Frequency Identification)认证协议存在的安全隐私保护弱点以及成本过高问题,提出一个基于PUF(Physical Unclonable Functions)的轻量级RFID安全认证协议。利用PUF与LFSR(Linear Feedback Shift Register)实现阅读器和标签之间强的安全认证。另外,协议中增加了阅读器二次验证安全机制,为了保证阅读器与标签共享密钥同步,添加了不良攻击标识M等手段,解决了已有认证协议存在的多种安全漏洞。安全性分析表明该认证协议不仅成本低,而且能够有效地抵抗物理攻击、DoS攻击、同步破坏攻击等多种攻击,满足了认证协议的正确性、安全性、隐私性。     

Neapolitan Yellow Tuff as raw material for lightweight aggregates in lightweight structural concrete production

The possibility of using Italian zeolitized volcanoclastites for the production of lightweight aggregates in the building industry has been tested.The present paper definitely demonstrates the good attitude of the Neapolitan Yellow Tuff (NYT) for the production of lightweight expanded aggregates (LEA) with bulk densities ranging between 0.9 and 1.1 g/cm³. LEAs showing these features, usually manufactured with clays, are mainly used in the production of lightweight structural concretes (LSC). The physical characterization of LEAs was carried out by means of: grain size analysis, loose weight, mean density of the single grain, water absorption after 30 min and 24 h, and strength of particles (UNI-7549). Afterwards, LEAs were mixed with sand, cement and water to prepare cubic concrete blocks following the UNI specifications (UNI-7549-12). On these specimens, the unit weight and uniaxial compressive strength after 28 days were determined.The investigated parameters measured both on LEAs and concretes, are comparable with those measured on materials commonly traded in Italy.The obtained results foresee interesting potential applications of a raw material characterized by a low exploitation cost and a widespread availability on the Italian territory.     

Manufacturing of Long Products Made of Innovative Lightweight Materials

The processing of innovative lightweight materials to sheet metal components and assemblies with globally or locally defined properties is the object of this work. It takes a load-dependent design of components and assemblies, for example, based on the composition of different construction materials or a targeted setting of component areas with specified characteristics to fully exploit the lightweight potential when substituting conventionally used materials. Different process chains for the manufacturing of roll-formed long products made of magnesium alloys and high-strength steels with locally defined properties will be presented in this paper. Depending on the kind of material to be formed and the desired product characteristics, different temperature managements are needed for capable processes. Due to limited formability at room temperature, magnesium alloys require a heating of the forming zones above 200–225 °C throughout the bending process in order to activate additional gliding planes and to avoid any failures in the radii. The realization of local hardening effects requires at least one process-integrated heat treatment when roll forming manganese–boron steels. For both processes, it is imperative to realize a heating and cooling down or quenching appropriate for the manufacturing of long products with the required quality. Additionally, proper line speeds that allow a continuously operated economical production have to be considered. Research results including design, FEA, realization and experimentation of the mentioned process chains and strategies will be described in detail.     

Material Elegance

In the everyday, elegance is a wholly subjective attribute. Whether we deem someone to be ‘elegant’ is entirely dependent on our own personal perception of their outward appearance. Here, Manuel DeLanda provides for architecture an objective interpretation of the elegant or smart solution in which ‘there is a measurable economy of means to achieve a certain outcome’. Through a brief historical survey, he traces an empirical tradition of material elegance. Copyright © 2007 John Wiley & Sons, Ltd.     

Tectonics and Textiles

Technical textiles are now omnivalent - used in many different everyday applications - and have been adopted by civil engineers and physicians alike. In an exhibition, ‘Extreme Textiles’ at New York's Cooper-Hewitt Museum last year, curator Matilda McQuaid brought these common but often ignored extraordinary materials to public attention. Here she highlights the high-performance qualities of this very special category of materials. Copyright © 2006 John Wiley & Sons, Ltd.     

Parametricism: A New Global Style for Architecture and Urban Design

Though parametricism has its roots in the digital animation techniques of the mid-1990s, it has only fully emerged in recent years with the development of advanced parametric design systems. Patrik Schumacher explains why parametricism has become the dominant, single style for avant-garde practice today and why it is particularly suited to large-scale urbanism as exemplified by a series of competition-winning masterplans by Zaha Hadid Architects. Copyright © 2009 John Wiley & Sons, Ltd.     

微硅漂珠复合低密度水泥体系的探讨

低密度水泥是解决低压易漏井固井水泥浆漏失的主要途径。研究了微硅漂珠复合低密度水泥体系,分析了该水泥体系的作用机理,并对微硅漂珠复合低密度水泥体系的水灰比与密度的关系、水泥浆配方、流变性、沉降稳定性等性能进行了评价。结果表明,微硅漂珠复合低密度水泥浆体系强度高、滤失量低、自由水含量低及稳定性能好,水泥浆密度为1.30—1.33 g/cm~3。微硅漂珠复合低密度水泥体系克服了漂珠低密度水泥和微硅低密度水泥的缺点,满足了定向井和水平井施工作业对水泥浆的要求。