基于非质点模型的纯方位解距离方法

目标距离是战场进行作战决策和武器使用时考虑的一个重要参数.在传统的二维被动跟踪系统基础上,将目标建模为椭圆刚体.论文借鉴修正极坐标(MPC)的思想,利用刚体目标的尺寸参数,建立目标的状态模型和测量模型.采用无迹卡尔曼滤波(UKF)算法进行解距离,为工程实现提供了可能性,并从不同的初始条件下分析了距离误差.Monte-Carlo仿真表明:在新的状态模型下利用UKF算法进行解距离,可以达到较高的精度.其中传感器与目标的相对速度和刚体目标的尺寸对距离解的精度影响较大.     

符号执行中高语句覆盖率的路径调度

符号执行和约束求解相结合的软件测试方法采用深度优先搜索的路径调度算法会造成测试路径聚居性问题,实际软件中存在路径爆炸,使得采用该算法的测试语句覆盖率低下。提出一种新的PSHC路径调度算法。先将路径分为前缀和后缀两部分,每次测试总是试图寻找这样的路径,该路径与已存在的路径具有最短的相同前缀,并且包含尽可能多的尚未被访问过的基本块作为其后缀。基于Phoenix漏洞发掘工具的实验结果表明,PSHC算法可以迅速提高测试的语句覆盖率到100%,有效解决由于深度优先搜索的路径聚居性导致的测试代码的局部性问题,PSHC算法产生的路径数与循环深度无关,软件规模越大,该算法的表现越好。     

组合型材参数化快速设计的方法研究

为了满足大型工程系统对组合型材的快速参数化设计要求,本文设计开发了一套针对组合型材的参数化绘图系统。系统在天喻参数化零件库的基础上,以其参数化和数据库技术做支撑,通过其参数化驱动的技术来绘制单个型材的截面图形,并通过一系列的变换矩阵对截面图形进行变换,以达到相互组合的目的;并根据组合后的图形数据,在特定的消隐算法的基础上,完成组合型材的水平与竖直方向的投影视图。文中分析了此系统的框架结构,并对所涉及到的关键技术,如型材的组合运算、方位视图的生成以及对型材视图的投影所涉及到的消隐算法进行了介绍,最后给出了此系统在某锅炉企业中的应用实例。     

机场视景模型参数化建模方法研究

随着计算机虚拟现实和视景仿真技术的发展与完善,用于提高视景的逼真度和视觉效果的技术在飞行模拟机视景仿真中已得到广泛的应用。但是,基于Multigen Creator等3D建模软件构建机场模型的缺点日益凸显:人工收集机场数据、手工绘制机场拓扑图的建模方法耗时、费力、效率低、缺乏灵活性和可复用性。针对这些问题,结合机场路网结构的特点,将参数化的思想引入到机场路网三维建模过程中,提出了一种基于交通拓扑约束的机场路网参数化三维建模方法,设计并实现了基于该方法的用于视景的机场路网模型参数化建模系统。该系统已成功应用到机场模型建模工作中,建模速度较之传统方法有了显著的提高,而且制作出来的模型可以复用,系统在稳定性、可扩展性和可移植性方面表现出色,并具有很强的真实感和沉浸感。     

Collaborative assignment using belief-desire-intention agent modeling and negotiation with speedup strategies

In this paper, we propose a distributed agent model that applies belief-desire-intention (BDI) reasoning and negotiation for addressing the linear assignment problem (LAP) collaboratively. In resource allocation, LAP is viewed as seeking a concurrent allocation of one different resource for every task to optimize a linear sum objective function. The proposed model provides a basic agent-based foundation needed for efficient resource allocation in a distributed environment. A distributed agent algorithm that has been developed based on the BDI negotiation model is examined both analytically and experimentally. To improve performance in terms of average negotiation speed and solution quality, two initialization heuristics and two different reasoning control strategies are applied, with the latter yielding different variants of the basic algorithm. Extensive simulations suggest that all the heuristic-algorithm combinations can produce a near optimal solution soon enough in some specific sense. The significance and applicability of the research work are also discussed.     

Automatic Construction and Verification of Isotopy Invariants

We extend our previous study of the automatic construction of isomorphic classification theorems for algebraic domains by considering the isotopy equivalence relation. Isotopism is an important generalisation of isomorphism, and is studied by mathematicians in domains such as loop theory. This extension was not straightforward, and we had to solve two major technical problems, namely, generating and verifying isotopy invariants. Concentrating on the domain of loop theory, we have developed three novel techniques for generating isotopic invariants, by using the notion of universal identities and by using constructions based on subblocks. In addition, given the complexity of the theorems that verify that a conjunction of the invariants form an isotopy class, we have developed ways of simplifying the problem of proving these theorems. Our techniques employ an interplay of computer algebra, model generation, theorem proving, and satisfiability-solving methods. To demonstrate the power of the approach, we generate isotopic classification theorems for loops of size 6 and 7, which extend the previously known enumeration results. This work was previously beyond the capabilities of automated reasoning techniques. The author’s work was supported by EPSRC MathFIT grant GR/S31099.     

Behaviour based on decision matrices for a coordination between agents in a urban traffic simulation

This paper describes a multi-agent coordination mechanism applied to intersection simulation situations. In a goal of urban traffic simulation, we must consider the dynamic interactions between autonomous vehicles. The field of multi-agent systems provides us some studies for such systems, in particular on the coordination mechanisms. Conflicts between vehicles (i.e. agents) are very frequent in such applications, and they may cause deadlocks, particularly at intersections such as crossroads. Our approach is based on the solving of two player games/decision matrices which characterize three basic situations. An aggregation method generalizes to n-player games for complex crossroads. The objective of this approach consists in searching basic two-player matrices for solving n-agent problems. To explain the principle, we describe our approach for a particular case of crossroad with three agents. Finally, the obtained results have been examined via a tool of road traffic simulation, ARCHISIM. We assume also that the global traffic replicates the behavior of agents in different situations.     

基于Pro／E的机械产品设计

基于Pro／E特征建模、参数化、全数据相关的特点,不仅能实现零部件的参数化实体建模,也可以方便地建立从三维模型到二维工程图的转换,有效地缩短设计时间,提高设计效率与质量。通过对Pro／E特点的讨论,结合台式钻床产品设计实例,论述了Pro／E在机械产品设计中的应用。     

单片机中基于查表法的多变量函数求解方法设计

针对多变量非线性复杂函数关系式在单片机中难以实现的问题,提出了一种快速有效的查表求解算法。首先建立顺序存储数据块,接下来查找输入变量在已存变量存储块中的自然序号,最后利用查得的变量自然数序号及事先确定的算法查找这些变量所对应的函数值的存储地址,进而得到计算结果。实现了非线性复杂关系式的快速精确求解,可推广于各种运算能力有限的单片机,提高了单片机的整体使用效率。