公交车停靠诱发交通瓶颈的元胞自动机模拟

利用双车道元胞自动机模型,研究公交车停靠对道路混合交通流的影响.针对港湾式和非港湾式两种不同公交车站设置,在开放边界下模拟了公交车停靠所产生的交通瓶颈问题,给出了车辆入流概率-公交车比例相平面上的相图,区分了自由流相和拥挤相,研究了相图各区中公交车站附近的平均密度和速度分布图,比较了两种公交车站情况下的道路交通流的动力学特征.研究发现,当公交车比例较小时,与非港湾式车站相比,港湾式车站可以显著改善车站处的交通状况. 关键词： 元胞自动机 混合交通流 交通瓶颈 公交车站     

ARINC659总线桥接的设计及对总线同步的影响分析

ARINC659总线因其在时间和空间上均提供了完备的故障冗余和操作健壮性,已经逐渐在对数据通信确定性及故障沉默和屏蔽要求较高的航天领域中展开应用。为了使ARINC659总线能够更好的适应航天器综合电子系统的高度冗余容及分布式控制的需求,对一种能够在不同设备中ARINC659总线之间相互桥接的技术进行了研究,进而实现分布式综合电子系统中所有硬件模块的统一时序规划和通信调度,可以显著提升系统中的资源共享、并行处理、故障冗余及分布式控制能力,同时也为关键系统中不同设备中的硬件模块间实现严格的时序关系操作提供了一种解决方案。最后就桥接对ARINC659总线同步机制的影响进行了分析,据此提出了桥接设计的约束和实现规则。     

A New System of the Real Time Infrared Scene Simulator

This paper represents a new real-time infrared scene simulator. It has two PENTIUM 266MHz CPUs, the hardware of Z-BUFFER and the architecture based on PCI bus. The hardware architecture of the system and the schematic diagram are given and show how the great significance was achieved. Finally , the experimental results indicate that the simulator can meet the great demand of application in practice.     

一种新型飞行器管理计算机的设计和实现

围绕新一代先进航空飞行器,对高度综合化飞行器管理计算机的需求,国内外争相开展新型容错计算机的相关技术研究。ARINC 659背板总线因其强实时性、高带宽、抗干扰和容错能力强而著称,现已成为航空电子设备标准背板总线,也已成为模块化、综合化架构航电系统的关键技术。因此,基于ARINC 659总线容错计算机的研制已逐渐成为高可靠航空电子系统研究的热点和重点。提出了基于ARINC 659总线的新型容错计算机构架设计方案、余度管理以及故障实时诊断与隔离等关键技术。     

飞行试验测试采集的AFDX总线检测分析技术研究

在航空产品的航电系统跨代升级中,AFDX总线数据的检测分析是飞行试验对航空产品航电系统进行科研鉴定的一项重要技术手段,针对复杂航空电子环境下的采集记录的AFDX总线数据的多类、随机性等特点,提出了AFDX总线消息识别、帧检测、丢包检测分析方法及实现技术,并结合采用了AFDX总线周期检测分析算法,设计了AFDX总线的检测分析技术,实现了飞行试验AFDX总线的检测分析,最后在某试验机AFDX总线飞行试验测试中进行了应用,试验表明该AFDX总线检测分析技术满足飞行试验对航电系统进行科研鉴定的需求。     

基于1553B总线的运载火箭供电测控系统设计

新一代运载火箭采用低温动力技术,测量系统获取飞行过程遥测参数的同时,需要完成火箭发射前低温推进剂加注期间压力、温度等关键参数的可靠获取。相比传统火箭,对测量系统在供配电和地面测控的可靠性设计、连续工作时间、测试性、扩展性和箭地接口设计提出了较高要求,对此文中提出了一种基于1553B总线的供电测控系统,介绍了系统的硬件和软件组成、功能和测控信息流向,分析了系统设计的4项关键技术：单机设备智能化设计、箭地接口简化设计、总线通信协议和高可靠PXI冗余备份设计。设计的新型供电测控系统在新一代运载火箭各项大型地面试验中成功实现了工程应用,系统方案设计的正确性得到了充分验证,系统方案在其他项目中得到了推广。     

武汉市高校间公交线路的最优化设计

对武汉市高校间公交线路进行了设计.首先根据互访人数对25所代表性高校间的距离进行修正,采用聚类分析模型将25所高校划分为3类,分别以到达目的地所经过路程和线路总长度作为学生和公交公司的满意度指标,在每一类别内建立基于学生和公交公司满意度最大化的多目标优化模型,采用线性加权法将其转化为单目标优化模型并采用模拟退火算法进行模型求解.结果表明设计的3条公交线路长度适宜,学生到达目的地所经过路程结果较为合理.     

超导磁体低温液位监测单元的设计与实现

介绍了一种应用于超导磁体的低温液位监测单元的设计与实现.设计了压控电流源电路和电压-频率转换电路用于液氦的液位测量,并设计了电容-频率转换电路用于液氮的液位测量;设计了以STM32微控制器为核心的数字电路,用于压控电流源的控制、频率信号的处理和液位监测数据的数字化显示;同时通过CAN总线把液位的监测数据自动发送至上位机,完成液位监测单元的远程控制.测试结果证明了该设计的可行性.     

Dynamic vibrations of a damageable viscoelastic beam in contact with two stops

A model for the material damage, due to dynamic vibrations of a Kelvin‐Voigt viscoelastic beam whose tip is constrained to move between two stops, is presented and numerically analyzed. The contact of the free tip with the stops is described by the normal compliance condition. The evolution of damage of the beam's material, which measures the reduction of its load carrying capacity, is modeled with a parabolic inclusion. The existence of the unique local solution is stated. A numerical algorithm is presented, in which spatially it is approximated by finite elements, and the time derivatives are discretized with the Euler scheme. Error estimates are derived for sufficiently regular solutions, and four numerical simulations are shown. © 2012 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2013     

Combined bottleneck effect of on-ramp and bus stop in a cellular automaton model

The combined bottleneck effect is investigated by modeling traffic systems with an on-ramp and a nearby bus stop in a two-lane cellular automaton model. Two cases, i.e. the bus stop locates in the downstream section of the on-ramp and the bus stop locates in the upstream section of the on-ramp, are considered separately. The upstream flux and downstream flux of the main road, as well as the on-ramp flux are analysed in detail, with respect to the entering probabilities and the distance between the on-ramp and the bus stop. It is found that the combination of the two bottlenecks causes the capacity to drop off, because the vehicles entering the main road from the on-ramp would interweave with the stopping (pulling-out) buses in the downstream (upstream) case. The traffic conflict in the former case is much heavier than that in the latter, causing the downstream main road to be utilized inefficiently. This suggests that the bus stop should be set in the upstream section of the on-ramp to enhance the capacity. The fluxes both on the main road and on the on-ramp vary with the distance between the two bottlenecks in both cases. However, the effects of distance disappear gradually at large distances. These findings might give some guidance to traffic optimization and management.