基于Multigen的无人机任务飞行仿真系统

介绍基于Multigen仿真软件Multigen Creator, Creator Terrain Studio和Vega Prime的无人机任务飞行仿真系统,在Vega Prime中建立无人机的飞行控制运动函数,实现无人机模型在虚拟仿真场景中的六自由度运动。基于.NET 2003环境下多线程编程技术和SBS网络数据传输,实现该系统的实时应用。仿真结果表明该系统能较好地模拟无人机作战飞行任务。     

Experimental and simulation studies on the performance of standing wave thermoacoustic prime mover for pulse tube refrigerator

The thermoacoustic prime mover (TAPM) has gained considerable attention as a pressure wave generator to drive pulse tube refrigerator (PTR) due to no moving parts, reasonable efficiency, use of environmental friendly working fluids etc. To drive PTCs, lower frequencies (f) with larger pressure amplitudes (ΔP) are essential, which are affected by geometric and operating parameters of TAPM as well as working fluids. For driving PTRs, a twin standing wave TAPM is built and studied by using different working fluids such as helium, argon, nitrogen and their binary mixtures. Simulation results of DeltaEc are compared with experimental data wherever possible. DeltaEc predicts slightly increased resonance frequencies, but gives larger ΔP and lower temperature difference ΔT across stack. High mass number working fluid leads to lower frequency with larger ΔP, but higher ΔT. Studies indicate that the binary gas mixture of right composition with lower ΔT can be arrived at to drive TAPM of given geometry.     

实现非单调关联故障树PIS的联合技术

采用“非正规”二元决策图（BDD）技术获取最小形割集 (MCS)可能存在掩盖非单调底事件作用的弊端”。以“继承”关键技术为基础,提出了用统一编码的“正规”BDD技术来获取非单调关联故障树的MCS。结合Q-M算法,研究了联合获取非单调关联故障树的质蕴涵集(PIS)的完整过程。实际例证表明,所述方法不但能够准确地析出非单调关联故障树的MCS,而且能够自动地获取其PIS。     

基于C语言的RSA算法高效实现

RSA算法是现代公钥密码体制事实上的标准,虽然它有被椭圆曲线密码算法（ECC）取代的局势,但是研究RSA加密算法还有一定的实际意义。深入讨论RSA算法的实现细节,对RSA的快速实现给出一种高效实用算法。     

求解关系模式中一个候选关键字的一种有效算法

通过分析关系模式的属性在函数依赖中所起的作用，发现在关系模式中的部分属性必定为主属性，而部分属性必定为非主属性，可以通过减少对属性的搜索次数，从而提高算法的效率，降低算法的时间复杂性。为此，本文提出一种切合实际的求解候选关键字的有效算法。     

A distance measure for large graphs based on prime graphs

Graphs are universal modeling tools. They are used to represent objects and their relationships in almost all domains: they are used to represent DNA, images, videos, social networks, XML documents, etc. When objects are represented by graphs, the problem of their comparison is a problem of comparing graphs. Comparing objects is a key task in our daily life. It is the core of a search engine, the backbone of a mining tool, etc. Nowadays, comparing objects faces the challenge of the large amount of data that this task must deal with. Moreover, when graphs are used to model these objects, it is known that graph comparison is very complex and computationally hard especially for large graphs. So, research on simplifying graph comparison gainedan interest and several solutions are proposed. In this paper, we explore and evaluate a new solution for the comparison of large graphs. Our approach relies on a compact encoding of graphs called prime graphs. Prime graphs are smaller and simpler than the original ones but they retain the structure and properties of the encoded graphs. We propose to approximate the similarity between two graphs by comparing the corresponding prime graphs. Simulations results show that this approach is effective for large graphs.     

基于Creator/Vega Prime的单件生产系统虚拟现实仿真

为了对一个单件生产系统调度过程进行虚拟现实仿真,文中首先采用多线程方式编写了单件生产系统的实时仿真程序,此程序可仿真各工件在各机器上的调度过程.为了使仿真过程可视化,使用三维建模工具Creator建立了这个单件生产系统的模型,并在VS2003环境下由仿真程序调用Vega Prime工具包对模型进行驱动,最终实现了对单件生产系统调度过程的虚拟现实仿真.从仿真结果来看,可以清晰直观地看到该单件生产系统的工作过程,证明此方法正确、有效,并可以推广到更复杂的生产系统中.     

素数管理软件

本文作者在研制素数管理软件的过程中，提出并解决了字节存储、动态生成、自动定位以及数据预处理等多项技术，在ＩＢＭ ＰＣ及其兼容机上实现了２＾３１－１范围内全部素数的窗口管理。此外还提供了六个素数计算有关的扩展功能如因子分解、求本原根、求π（Ｘ）等等。整个系统约１７０ＫＢ，并且运行时对存储空间无任何额外要求，因而即使在无硬盘的ＰＣ机上亦可方便使用，使数学工作者和密码学研究人员从此有了一个理想的辅助工具     

某型飞机特种设备虚拟仿真训练系统设计

分析了特种设备课程的教学现状,介绍了某型飞机特种设备虚拟仿真训练系统的总体结构。利用Client/Server网络通信模式和TCP/IP通信协议,实现了系统间的数据通信;运用OpenGL纹理映射技术实现了虚拟仪表的绘制;采用Flash技术构建了设备原理演示系统;选用VegaPrime开发了视景系统。     

Prime algebraicity

A prime algebraic lattice can be characterised as isomorphic to the downwards-closed subsets, ordered by inclusion, of its complete primes. It is easily seen that the downwards-closed subsets of a partial order form a completely distributive algebraic lattice when ordered by inclusion. The converse also holds; any completely distributive algebraic lattice is isomorphic to such a set of downwards-closed subsets of a partial order. The partial order can be recovered from the lattice as the order of the lattice restricted to its complete primes. Consequently prime algebraic lattices are precisely the completely distributive algebraic lattices. The result extends to Scott domains. Several consequences are explored briefly: the representation of Berry’s dI-domains by event structures; a simplified form of information systems for completely distributive Scott domains; and a simple domain theory for concurrency.