基于云计算安全体系架构的研究

随着计算机与互联网的发展,云计算与物联网、智慧地球等概念一样备受关注。目前云计算已从产生到实质发展阶段,因此云计算的安全问题备受关注,近年来成为计算机学科领域的研究热点。在此背景下,首先介绍了云计算的概念、特点及服务模式,并在此基础上总结了云计算所面临的安全隐患,最后提出了云计算中确保信息安全的解决方案。     

A new method for the synthesis of organic–polyoxometallate hybrid compounds

The reaction of the Na₂MoO₄ or Na₂WO₄ salt with organic amine and PCl₅, SiCl₄ or TiCl₄ in hydrochloric acid medium under hydrothermal conditions yields organic–polyoxometallate hybrid compounds, with the following reaction formula: Na₂MO₄ + Lewis-base + XCl_n + HCl → (Lewis-baseH)_m(XM₁₂O₄₀) + NaCl + H₂O (M = Mo or W; X = P, Si, Ti,; n = 3–5). By using this method, four new complexes, [(CH₃)₂NH]₃[H₃PW₁₂O₄₀] (1), (C₂H₅OH)₃(H₃PMo₁₂O₄₀) (2), [DMDA]₂[H₄SiW₁₂O₄₀]·H₂O (3) (DMDA = 1 N,3 N-dimethyl-1,3-diazolidine) and [(DAN)₆][H₄TiW₁₂O₄₀]·4H₂O (DAN = 4,4′-dianiline) (4), were obtained, and their crystal structures are reported. Thermal analysis of 1, 2 and 4 has been carried out. The thermal analysis indicates that the Keggin anion skeleton begins to decompose at about 300 °C. The possibility of constructing hydrogen-bond interactions by association between the polyoxometallate and the organic compound is explored. The roles of solvents and organic groups in the formation of specific crystalline architectures are discussed. The crystal structure of [H₄TiW₁₂O₄₀], a hetero-transition-metal Keggin polyoxometallate with a square-plane TiO₄, has been reported. Four architectures developed by hydrogen-bond associations of different Keggin polyoxometallates and organic bearing N–H or O–H donor functions are described. The selected organic modules (4,4′-dianiline, 1,3-dimethylimidazolidine, dimethylamine and ethanol) possess hydrogen-donor functions to allow them to act as bridges between polyoxometallate groups. Depending on the nature of the donor group, the number of hydrogens available for bonding, the geometric features and the sizes of the organic modules, diverse assembling patterns have been observed ranging from one-dimensional to three-dimensional networks. For all the networks, H₃O⁺ and H⁺ act as actual linkers between the molecular units.     

Three-dimensional key in a modified joint transform correlator encryption scheme

We propose a modified encryption joint transform correlator scheme that introduces an additional random phase mask. The positions of both the conventional and the new mask are crucial for successful recovery of the original data. Although the two random phase masks are 2D, variation of their relative distance constitutes an additional dimension. Consequently by including this notion, both random phase masks act as a 3-dimensional (3D) key code increasing thereby the security with respect to the conventional JTC encryption scheme. We employ this scheme to multiplex encrypted data, displacing the encoding masks. During decryption of the multiplexed information, we only reconstruct the object that matches the correct predetermined 3D key code, i.e. that matches the random masks positions in the encryption step. We present actual experimental results, by using BSO crystal as recording medium, as well as their respective analysis.     

《汇编语言》课程设计的改革与实践

本通过对《汇编语言》课程设计各环节的深刻讨论，在总结以往工作经验的基础上，为读推荐了一种较实用的《汇编语言》课程设计的改革方案，经实践检验具有一定的推广价值。     

基于多媒体仿真的建筑CAD系统模型

为使新型 CAD系统具有更高水平的集成性和替代人工能力 ,提出了一个基于多媒体仿真的建筑结构 CAD系统设计模型 ( MSCAD)。该模型的基本结构包括设计资源处理器、实体建模器、仿真分析器、设计成果演示器。预研系统已实现了形态模型与行为模型的统一表达 ,创造性地综合使用了计算机图形学和计算几何等技术方法。介绍了该模型的技术背景和需求 ,指出了 MSCAD系统模式的可实现性和该软件推广应用的商业前景     

以太网变换机体系结构与实现技术分析

分析了以太网交换机的交换模式与体系结构，并对交换机所采用的专用芯片技术作了介绍。     

徽派建筑的现代化应用——以合肥至福州铁路南陵站建筑概念方案设计为例

作为徽文化的重要组成部分,徽派建筑在当今应满足建筑的现代化需求,并能代表皖南地区的形象,从而使自身的建筑理念发扬光大。这一思想在合肥至福州铁路段南陵站的设计中得到了体现。     

Synthesis and characterizations of two anhydrous metal borophosphates: M2BP3O12 (M=Fe, In)

Two members of M^III₂BP₃O₁₂ borophosphates, namely Fe₂BP₃O₁₂ and In₂BP₃O₁₂, were synthesized by the solid-state method and characterized by the X-ray single crystal diffraction, the powder diffraction and the electron microscopy. They both crystallize in the hexagonal system, space group P6(3)/m (no. 176) and feature 3D architectures, build up of the M₂O₉ units and B(PO₄)₃ groups via sharing the corners; however, they are not isomorphic for the different crystallographically distinct atomic positions. Optical property measurements of both compounds and magnetic susceptibility measurements of Fe₂BP₃O₁₂ also have been performed. Moreover, in order to gain further insights into the relationship between physical properties and band structure of the M^III₂BP₃O₁₂ borophosphates, theoretical calculations based on density functional theory (DFT) were performed using the total-energy code CASTEP.     

Automatic Identification of Customized Instruction Based on Multiple Attribute Decision-Making for Multi-Issue Architectures

This paper illustrates the importance of the configuration of function units and the change of an application’s critical path when using instruction set extension (ISE) with multi-issue architectures. This paper also presents an automatic identification approach for customized instruction without input/output number constraints for multi-issue architectures. The approach identifies customized instructions using multiple attribute decision-making based on the analysis of several attributes for each candidate...     

LINUX系统的硬件配置方法

Ｌｉｎｕｘ将所有系统（包括硬件设备）都表示为文件，而配置一个文件系统就是使计算机系统可以使用一个具 体的设备，如：磁盘（硬盘或软盘），ＣＤ－ＲＯＭ等等。本文针对Ｌｉｎｕｘ系统进行硬件配置的方式展开论述，以 期提供为用户的计算机系统合理配置硬件、提高使用Ｌｉｎｕｘ系统的能力。