一种航空武器数据链MAC协议设计与研究

MAC协议是航空武器数据链组网通信的重要技术,网络的性能依赖于所采用的多址接入协议,也是航空武器数据链研究的难点之一。固定分配、竞争和预约三大类MAC协议各有优缺点以及适应场景,需要根据应用需求设计对应的多址接入协议,以满足通信网络的战术和技术性能指标。在分析数字化战场通信网络——战术数据链组网通信应用的主要MAC协议的基础上,结合航空武器数据链的通信特点和体系结构,提出一种基于固定分配TDMA的航空武器数据链MAC协议——ODTCFMA协议,并对协议的时延性能进行了仿真和分析。分析结果表明,该协议能够同时满足编队战术协同和武器制导的低时延要求,对航空武器数据链的研究具有一定的借鉴意义。     

飞机航空电子综合火控系统开发环境仿真

针对轰炸飞机航程远、乘员多和中远程精确打击的情形,开发基于1553B总线具有动态仿真能力的航空电子综合火控系统开发环境系统,分析了轰炸机航空电子综合火控系统开发环境系统的组成和功能,给出了开发环境系统顶层设计、子系统模块化设计思想和系统关键技术,最后进行了开发环境系统动态联试和分析.该系统可用于航空电子综合火控系统研制设计全过程.     

Decommissioning and paramilitary strategy in Northern Ireland: A problem compared

This study examines the problems of paramilitary decommissioning in Northern Ireland. It analyses why decommissioning has become so contentious in the Northern Ireland peace process. Decommissioning, though, is not a unique or intrinsically insurmountable problem. This is demonstrated by highlighting the issue in international context. Three examples of decommissioning in conflict resolution processes are assessed: the Lebanon, El Salvador and Mozambique. These varied examples do supply some limited lessons for Northern Ireland. This study argues that the explanation for the intractability of decommissioning in Northern Ireland resides, to a greater extent, in the tactical and strategic reasoning of the main paramilitary groupings in Northern Ireland. The factors that condition their thinking, however, can be found in the nature of the peace process itself which provides the paramilitiaries with every incentive to retain possession of their weapons.     

模糊理论与D-S理论在指控系统目标识别融合中的应用

多传感器信息融合技术已获得了普遍的关注和广泛的应用,其理论和方法已成为智能信息处理的一个重要领域,模糊理论与证据理论(D-S)是主要的技术之一.在某试飞指控系统中,为了获得可靠的识别结果需要目标识别的融合问题.系统的从实际出发提出了基于模糊理论与D-S理论的目标识别融合方法.仿真计算结果表明,该模型和方法具有方法简单、运算量小和识别结果可靠等优点,具有一定的理论意义和使用价值.     

一类微分方程组极限环的不存在性

在系统奇点唯一的条件下,研究了一类微分方程组不存在极限环的的充分条件,运用和发展了以往的结果。     

Evaluation of effectiveness of polymer coatings in reducing blast-induced deformation of steel plates

Incorporating elastomers such as polymers in protective structures to withstand high energetic dynamic loads, has gained significant interest. The main objective of this study is to investigate the influence of a Polyurea coating towards the blast-induced response in steel plates. As such, Polyurea coated steel plates were tested under near-field blast loads, produced by the detonation of 1 kg of spherical nitromethane charges, at a standoff distance of 150 mm. Mild steel (XLERPLATE 350) and high-strength steel (BIS80) plates with thicknesses of 10 mm were Polyurea coated with thicknesses of 6 mm and 12 mm on either the front (facing the charge) or the back face. The deformation profiles were measured using 3D scanning. Numerical simulations were performed using the non-linear finite element code LS-DYNA. The strain-dependent behaviour of the steel and Polyurea were represented by Johnson-cook and Money-Rivlin constitutive models, respectively. The numerical models were validated by comparing the plate deflection results obtained from the experiments and were then used in the subsequent parametric study to investigate the optimum thickness of the Polyurea coating. The results indicate that back face coating contributes towards an approximately 20% reduction in the residual deformation as well as the absence of melting of the Polyurea layer, while the front-face coating can be used a means of providing additional standoff distance to the steel plates.     

基于梯度矢量流的水平集算法

针对传统水平集分割图像会出现演化曲线停止于梯度的局部极大值或孤立的边缘处的缺点,对速度停止项进行了改进.该方法将梯度阈值和梯度矢量流引入速度停止项中,利用梯度阈值来使边缘得到更好的保持;利用梯度矢量流来代替梯度场以扩大边界梯度场吸引曲线的范围,避免出现演化曲线停止于梯度的局部极大值或孤立的边缘处的现象.实验结果表明该方法优于传统水平集方法.     

ADVANCING THE GOALS OF NPT ARTICLE VI

International technical cooperation on issues relevant to the challenges of nuclear disarmament can demonstrate commitment to obligations under Article VI of the Treaty on the Non-Proliferation of Nuclear Weapons, strengthen the security of fissile materials and weapons, and develop technical approaches to support more ambitious disarmament activities in the future. Including non-nuclear weapon states would ensure that their views are taken into account and would invest them in developing solutions to key challenges. This article discusses three areas for technical cooperation that would build on past activities and that could produce such benefits as improved protection, control, and accounting of nuclear weapons and fissile material; enhanced transparency for nuclear weapon complexes; and mechanisms for international management of sensitive civilian nuclear facilities. International cooperation in each of these areas could provide a technical basis for pursuing possible future disarmament negotiations and substantively demonstrate commitment to Article VI.     

基于仿真的竞争失效产品步降加速寿命试验优化设计

针对竞争失效产品加速寿命试验存在试验时间长、费用高、效率低的问题,提出了一种基于Monte-Carlo仿真的竞争失效产品步降加速寿命试验优化设计方法.采用Monte-Carlo对步降加速寿命试验进行仿真模拟,以正常使用应力下的p阶分位寿命渐进方差估计最小为目标,以各试验应力水平及对应应力下的试验截尾数作为设计变量,采用MIE理论进行统计分析,建立了基于仿真的竞争失效产品步降加速寿命试验优化设计模型.最后,通过实例分析表明:该方法具有可行性、有效性.     

一类二阶微分方程Poincaré分岔极限环的不存在性

讨论一类二阶微分方程x¨+εf(x,x.)x.+g(x)=0的Poincar分岔极限环的不存在性,利用一阶Mel’nikov函数直接从整体上进行分析讨论,得出了若干充分条件和判别准则。