直升机飞行视景仿真实现

为了用视景仿真技术模拟直升机的飞行姿态,通过三维视景建模软件Multigen Creator,建立了直升机、地形场景的视景模型,以三维仿真软件包OpenGVS作为图形开发引擎,用现代软件工程的方法,在VisualC++6.0平台上构建了直升机飞行仿真软件的整体框架,完成其中关键模块的代码编写.对于输入模块,用游戏杆作为视点变换的控制工具,运用Direct-Input接口技术对其编程.通过实例运行所编制代码,在飞行操作杆控制下,系统在飞行模拟过程中实时跟随性较好,达到理想的飞行仿真效果,从而为以后进一步研究直升机综合操纵特性和飞行品质作了一个预先性仿真研究.     

一种新型套筒天线宽频特性的HFSS仿真分析

针对传统套简单极子天线结构变量复杂、要做到3:1的频带宽度难的问题,利用电抗补偿方法设计了一款位于特殊接地铜管上的双层套筒偶极子天线,并利用HFSS软件对结构进行仿真分析,找到影响频带及反射特性的结构参数,通过软件自带的优化功能,对各个参数进行仿真优化,得到工作在800-960MHz,1710-1920MHz,2400-2483MHz频带范围内驻波系数低于1.5的实用套筒天线结构,包含目前移动通信所用频带:2G、3G和WLAN.天线在同一个结构上实现多频工作,且在各个频段内反射很小,节省了天线资源,利于系统集成.     

模糊自整定PID的船舶蒸汽动力负荷控制

船舶蒸汽动力装置自动控制的首要任务是机组的负荷控制。传统的PID控制算法由于具有结构简单、易于实现、可消除静差等优点得到了广泛的应用,但它受控制对象的影响较大,只有在各参数整定良好的前提下才能得到满意的控制效果。根据上述情况,结合船舶蒸汽动力单元工况变化频繁的特点,提出一种基于输出响应的自适应PID算法,以提高控制系统适应负荷变化的能力。方法在保留传统定值PID控制算法优点的同时,引入模糊控制在线整定PID控制参数,改善了机组的负荷控制特性,具有一定的工程应用价值.     

一种基于双线性链表结构编码的遗传算法

针对基于以往经典编码方式的遗传算法解决并行机大批量成组调度问题时的弊端,提出了一种基于双线性链表结构编码的遗传算法（DLGA）,并设计了相应的遗传算子。应用于某轮胎厂的硫化工序调度问题,进行了仿真分析。     

粗糙集理论在选矿生产成本分析中的应用

科学地分析影响原料消耗成本变化的主要因素,才能揭示成本变动原因,为成本控制提供有效依据.因此,提出基于粗糙集理论的原料消耗成本影响因素重要度确定方法.利用分类质量来度量各因素对原料消耗成本的影响程度,应用基于可辨识矩阵和逻辑运算方法求解决策表的最小简约,找出影响原料消耗成本的确定性因素和不确定性因素,为改进生产提供辅助决策支持.实例分析表明,该方法简捷实用,可定量分析影响因素对原料消耗成本的影响程度.     

A novel fault-tolerant execution model by using of mobile agents

The exponential expansion of the Internet and the widespread popularity of the World Wide Web give a challenge to experts on reliable and secure system design, e.g., e-economy applications. New paradigms are on demand and mobile agent technology is one of the features. In this paper, we propose a fault-tolerance execution model by using of mobile agents, for the purpose of consistent and correct performance with a required function under stated conditions for a specified period of time. Failures are classified into two classes based on their intrinsic different effects on mobile agents. For each kind of failure, a specified handling method is adopted. The introduction of exceptional handling method allows performance improvements during mobile agents’ execution. The behaviors of mobile agents are statistically analyzed through several key parameters, including the migration time from node to node, the life expectancy of mobile agents, and the population distribution of mobile agents, to evaluate the performance of our model. The analytical results give new theoretical insights to the fault-tolerant execution of mobile agents and show that our model outperforms the existing fault-tolerant models. Our model provides an effective way to improve the reliability of computer systems.     

曼彻斯特编码技术在测井数据传输中的应用研究

基于曼彻斯特码编码技术文章提出一种适用于石油测井下行数据传输链路的设计方案。采用Verilog HDL设计的曼彻斯特编、译码器,在ALTERA公司的QuartusⅡ6．0软件平台上完成了仿真,并在FPGA器件上实现了硬件测试．最后下行数据传输链路的发送端和接收端在6km的电缆模拟器上完成了系统测试。通过计算机仿真和工程实现验证了该设计方法的正确性和实用性。     

一种基于ENVI二次开发的遥感薄云去除方法的改进

近年来常用的同态滤波去云算法因其采用滤波器的局限性只能去除低频区域的云而无法去除高频区域的云。因此在分析传统的同态滤波去云算法的基础上,引入了空域滤波,采用中值滤波器对图像进行处理,旨在去除高频区域的云。而后在ENVI遥感图像处理软件平台中采用IDL语言实现了算法并对ENVI进行二次开发。经实验结果分析表明,该法是有效的,并且为遥感数据的后续应用提供了方便。     

基于FPGA的PCI总线接口设计与实现

文章提出了一种基于FPGA的PCI接口控制器的设计方案,重点叙述了PCI控制器核心的状态机的设计原理与结构,对时序设计进行了分析,并进行TN试仿真,经验证后速度和正确性均达到设计要求。     

Stability of three-dimensional metallic glass Ni68B21Si11

Under isothermal and linear heating conditions, the thermal stability of the three-dimensional metallic glass Ni₆₈B₂₁Si₁₁, produced by rapid quenching of the denucleated melt (RQDM), has been systematically studied using PE DSC7 differential scanning calorimetry in relation to denucleation of liquid alloy prior to rapid quenching, pre-anneal treatment of amorphous specimens, and cooling rate. The following results were observed. First, the thermal stability of metallic glass prepared by RQDM is obviously enhanced because of the removal of pre-existing nuclei in advance. This is substantiated by the experimental data showing that the projected life of three-dimensional metallic glass Ni₆₈B₂₁Si₁₁ is increased by an order of magnitude at 400 K. Secondly, pre-anneal treatment of the amorphous alloy leads to a reduction of temperature for the onset of crystallization,T _x, and crystallization heat, H. Finally, quenching rates have little effect on the thermal stability of amorphous alloys.