库函数调用的安全性分析

首先介绍缓冲区溢出机制和基于缓冲区溢出的攻击形式,从C程序员的角度讨论了三类常用的库函数在调用时可能引发的安全问题,并详细分析了缓冲区溢出的内在原因及可能被利用的攻击方法，如果在编程时能针对这些库函数的调用有意识地采取应对措施,无疑将减少缓冲区溢出漏洞,提高程序的安全性能。     

嵌入式协议栈缓冲区管理的简化实现方法

本文针对嵌入式系统网络协议栈的特点,设计了一种简洁、高效、且对存储资源要求很少的缓冲区管理策略。该策略基于缓冲区单次拷贝技术,克服了有些嵌入式系统存储控制器低效的存储块拷贝。除了提供缓冲区管理例程,还实现了缓冲区的动态分配与回收。最后,我们将实现源代码移植到X86嵌入式裸机平台的64K PCI扩展ROM中,基于该缓冲区管理设计了TCP/IP协议,并已经应用于无本地存储设备的超级刀片服务器上。     

人体骨架模型的建立

人体运动分析在计算机视觉研究领域中具有广泛的应用前景。人体骨架包含了很多的人体运动信息,且简单明了,所以对人体骨架提取具有很重要的意义。本文提出了一种人体骨架模型的建立方法,该方法在骨架提取方面有较强的去噪和抗干扰能力,有很好的鲁棒性,可提取更加有效的骨架图像,进一步结合人体解剖学的基础,建立了人体骨架模型,为人体特征识别(HID)和运动人体的实时追踪打下了坚实的基础。     

基于缓冲器的编码器接口扩展方法研究

在数据采集测控系统中,用于检测的绝对值角度编码器的输出很多是基于SSI接口,采用SSI接口的绝对值角度编码器输出有时需要连接到多个不同的独立测控系统,由于SSI接口是单访问接口,多主机共享往往是较难解决又不得不解决的问题,本文提出了一种缓冲式并行读取绝对值角度编码器值的方法,实现了信号的并行读取,并给出了硬件和软件设计的思想和方法。     

Fabricating Buffer Layers for YBa2Cu3Oy Coated Conductor by Surface Oxidation Epitaxy

Coated conductor of YBa2Cu3Oy(YBCO) withhighsuperconducting critical current (IC)is promisingfor many applications . To decrease weak link andlarge grain boundary angle it is i mportant to achievebiaxial textured YBCO.Sofar ,a fewtechniques havebeen appli…     

TIFF格式在设计与印刷中的作用

印前设计与制作软件日益丰富多样,支持输出的格式也越来越多.由于跨平台、多软件融合制作及文件的复杂性,需要解决输出时常出现的一些问题.TIFF格式可起到设计与印刷的桥梁作用,从而提高制作和输出所需要的效果.?＃     

Win32.SQLExp.Worm蠕虫病毒分析与对策

分析了Win32．SQt,Exp．Worm蠕虫病毒原理，并给出相应解决方案。     

Mechanistic modelling of the milling process using an adaptive depth buffer

A mechanistic model of the milling process based on an adaptive and local depth buffer is presented. This mechanistic model is needed for speedy computations of the cutting forces when machining surfaces on multi-axis milling machines. By adaptively orienting the depth buffer to match the current tool axis, the need for an extended Z-buffer is eliminated. This allows the mechanistic model to be implemented using standard graphics libraries, and gains the substantial benefit of hardware acceleration. Secondly, this method allows the depth buffer to be sized to the tool as opposed to the workpiece, and thus improves the depth buffer size to accuracy ratio drastically. The method calculates tangential and radial milling forces dependent on the in-process volume of material removed as determined by the rendering engine depth buffer. The method incorporates the effects of both cutting and edge forces and accounts for cutter runout. The simulated forces were verified with experimental data and found to agree closely. The error bounds of this process are also determined.     

Entropy maximisation and open queueing networks with priorities and blocking

A review is carried out on the characterisation and algorithmic implementation of an extended product-form approximation, based on the principle of maximum entropy (ME), for a wide class of arbitrary finite capacity open queueing network models (QNMs) with service and space priorities. A single server finite capacity GE/GE/1/N queue with R (R>1) distinct priority classes, compound Poisson arrival processes (CPPs) with geometrically distributed batches and generalised exponential (GE) service times is analysed via entropy maximisation, subject to suitable GE-type queueing theoretic constraints, under preemptive resume (PR) and head-of-line (HOL) scheduling rules combined with complete buffer sharing (CBS) and partial buffer sharing (PBS) management schemes stipulating a sequence of buffer thresholds {N=(N₁,…,N_R),0<N_i≤N_i−1,i=2,…,R}. The GE/GE/1/N queue is utilised, in conjunction with GE-type first two moment flow approximation formulae, as a cost-effective building block towards the establishment of a generic ME queue-by-queue decomposition algorithm for arbitrary open QNMs with space and service priorities under repetitive service blocking with random destination (RS-RD). Typical numerical results are included to illustrate the credibility of the ME algorithm against simulation for various network topologies and define experimentally pessimistic GE-type performance bounds. Remarks on the extensions of the ME algorithm to other types of blocking mechanisms, such as repetitive service blocking with fixed destination (RS-FD) and blocking-after-service (BAS), are included.     

实现基于RTCP协议的参考图象法的探讨

目前视频图象在 IP分组网中的传输正被日益广泛地应用 (如 :视频电话、视频会议 ) .但是 ,由于 IP分组网固有的特点 ,致使 IP分组包丢失的现象不可避免 ,并极大地影响了视频传输的服务质量 .由于参考图象选择法RPS(Reference Picture Selection)是一种较好的视频图象差错复原的方法 ,因此 ,为了改善因分组包丢失而对视频传输带来的质量下降问题 ,利用 RTCP协议提供反馈信息和利用参考图象选择法进行视频图象复原 ,实现了一种在 IP分组网中进行视频传输的差错控制机制 .实践证明 ,通过这种方法不仅可减小因分组包丢失而对视频图象信息带来的损害 ,而且可提高视频图象的传输质量 ,此方法适用于基于分组网的视频传输系统 .