浅析企业信息安全风险与对策

当前越来越多的企业已经把信息安全看做影响业务发展的核心因素之一,信息安全管理已经成为企业管理的重点。本文对当前企业信息安全风险的现状展开了探讨,并就信息安全政策,安全管理手段等方面进行了剖析,为企业做好、做强信息安全管理体系给出了一些通用性的标准,对企业构建信息安全管理体系,消除信息安全隐患,避免信息安全事件造成的损失,确保信息系统安全、稳定运行具有探索意义。     

Coding scheme based on spherical polar coordinate for control over packet erasure channel

Like feedback strategy, coding scheme is an important part of networked control system design as well. On the basis of spherical polar coordinate, a novel coding scheme is proposed for stabilization problem of discrete linear time invariant system subject to packet erasure channel with feedback. The coding scheme uses encoder without access to control inputs. In the case that a decoder does not use control inputs, a definite relation between the quantized data and the corresponding quantization error is established, which helps to analyze the stability of system, and a selective quantization method is adopted, by which finite data rate is obtained. In the case that a decoder uses control inputs, instead of quantizing the system state at each time step as usual, the encoder quantizes the initial state all the time by updating quantizer. Sufficient conditions guaranteeing the system stable are presented for two cases, respectively, and the corresponding design methods for coding schemes are given. Copyright © 2012 John Wiley & Sons, Ltd.     

Phase Equilibrium Investigations on Na–K–(β+β")-Alumina

The activities of Na₂O and K₂O dissolved in mixed-alkali Na–K–(β+β")-Al₂O₃ (NKBA) have been determined by using yttria stabilized zirconia (YSZ) as a solid electrolyte in the following galvanic cells: The approach enables to verify in situ the establishment and maintenance of the β/β"-equilibrium, and to characterize it as a function of the phase composition of NKBA. The results can be expressed as follows:      

Preparation and characterization of a series of polyamides with long alkylene segments: Nylons 12 20, 10 20,s 20,6 20, 4 20 and 2 20

Summary A series of nylons with long alkylene segments between amide groups were newly prepared by step-heating melt-polycondensation of 1,lS-octadecanedicarboxylic acid with various diamines. The prepared polyamides were characterized carefully. The results show that many properties of the prepared nylons change regularly with the length of methylene segments in diamines. In addition, nylon 2 20 has a relatively low molecular weight and much different melting and thermal decomposition behaviors in comparison with other nylons. Received: 21 June 2OO2/Revised version: 18 September 2002/ Accepted: 18 September 2002 Correspondence to Deyue Yan E-mail: dyyan@mail.sjtu.edu.cn Tel: 0086-21-54742863 Fax: 0086-21-54741297     

视频服务器拥塞控制算法的研究与实现

分析现有网络拥塞控制算法的优缺点,在此基础上,根据多媒体数据和嵌入式设备的特点提出改进的基于视频服务器的拥塞控制算法。此算法以UDP协议为基础,通过控制传输速率来降低丢包率和网络时延,提高了嵌入式设备的多媒体数据传输质量。同时,将此算法应用于基于TMS320DM6467T硬件开发平台和Linux操作系统的视频服务器上,并通过实验验证了算法的可靠性与实用性。     

Interbay物料自动搬运系统性能分析

Interbay物料自动搬运系统的运行效率对于晶圆制造系统影响较大,研究Interbay物料自动搬运系统的绩效具有较大的意义[1]。该文以带有捷径的单闭环背脊式布局的物料自动搬运系统为研究对象,通过问题描述,简化、假设将实际问题抽象为导引运输模型。然后,建立数学模型,采用Dijkstra算法确定工件搬运的最短路径。最后,利用Arena仿真软件建立含有导引运输设备的模型,采用控制变量法探究小车数量小车占用轨道的方式、调度规则等因素对于产出的影响,发现对于本文中的模型,其它条件相同时,搬运系统采用Release-at-end的控制方式,系统最大搬运量越大。     

浅谈信息管理技术在建筑施工企业项目管理中的应用简

信息技术与先进的管理思想相结合,创造性地利用信息技术,可以高效提升企业管理创新能力。本文从施工管理的视角,阐述了在石油化工行业大型炼化工程项目管理中,如何利用信息管理技术,构架起综合项目管理平台,采用工程验收平台和POWER ON项目管理软件来进行二次开发,结合具体工程实践,实现网上机械车辆结算。     

特殊教育幼儿园中的导视系统设计分析简

随着我国越来越重视对特殊需要儿童的教育,特殊儿童幼儿园的人性化设计也成为了近几年热门的设计方向。导视系统的设计在特殊儿童幼儿园中起着非常重要的作用,完善的导视系统设计能够创造人性化的特殊教育幼儿园环境、儿童主体意识的确立和强化、对特殊儿童意愿需求的尊重和理解。同时,也能够让特殊教育儿童在使用中感到非常方便、自然。本文旨在构建功能合理的、具有人情味的、准确体现环境意象的导视系统设计,并且通过优秀的导视系统设计提高儿童在空间内行动的便捷性和安全性,提高空间环境使用的品质。     

IN SITU LEACHING OF URANIUM USING DILUTE SULFURIC ACID AND MOLECULAR OXYGEN

The technical feasibility of in situ uranium leaching using dilute sulfuric acid and molecular oxygen has been assessed and the important process parameters examined by use of laboratory high pressure leaching columns.

The dilute H₂SO₄/O₂ lixiviant was effective in leaching uranium from the ore samples tested. The leaching process was chemical reaction rate limited and can be represented using pseudo first-order kinetics. The leaching rate constant is proportional to the proton concentration of the lixiviant.

Much of the uranium was leached from the ore before decomposition of carbonate minerals by the acid was complete. Acid consumption per pound of U₃O₈ increased sharply as the uranium recovery level exceeded 70%. There appears to be a minimum oxygen pressure for effective uranium leaching. A pressure of 2758 KPa was adequate for the ore samples tested     

PA66/UHMWPE合金的力学性能和微观结构研究

制备了PA66／uHMwPE／HDPE-g-MAH共混合金，并对其力学性能和微观结构进行了研究。结果表明，随着UHMWPE质量分数的增加，共混合金常温和低温下的缺口冲击强度都显著提高，拉伸强度和拉伸模量下降，但仍能保持较高的力学性能；添加了UHMWPE的PA66合金的断裂面有大量的空穴产生和应力发白现象。