Earliest Deadline First Scheduling with Active Buffer Management for Real-Time Traffic in the Internet

We studied the problem of QoS guarantee for differentiated services. A two-level hierarchical scheduling framework was deployed to separate QoS metrics. Due to its desirable property of minimizing the maximum packet lateness, the Earliest Deadline First (EDF) scheduling was adopted to provide the in-class scheduling for the time-sensitive traffic. We employed an EDF scheduler combined with an active buffer management scheme (CHOKe) to improve the fairness of resource allocation and to maintain a good delay performance for real-time applications. Simulation results showed that the proposed scheme can achieve a better delay performance and make a more fair bandwidth allocation between the real-time TCP and UDP connections than the First Come First Served (FCFS) scheduling with the drop-tail buffer management which is commonly deployed in traditional IP routers.     

双基地雷达实时测距与距离分辨

本文叙述了基线长为10km,以接收点为坐标原点的双基地雷达实时测距系统。最大测量距离为25.5km。方位角观察范围为0°至255°,仰角观察范围为0°至40°。测距系统能提供的角度分辨力为1°;能提供显示器的量化距离小于100m。采用十六位微机对目标离接收点的真实斜距进行了精确计算。在整个测距范围内,最大计算绝对误差不超过51m。以 DMA 实现快速数据读出,形成显示器的时基线。在同一波束位置上,本测距系统能处理10~6sec~(-1)数据率的目标,并给出它们的真实斜距。本测距系统计及了目标高度对斜距的影响。整个系统具有数模结合的特点,并保留了目标的幅度信息,为雷达操纵手识别目标提供方便。本文还讨论了双基地雷达的距离分辨力。     

基于粒子系统的流场实时模拟

数学模型计算结果的显示大多以后处理的形式出现，存在显示时间滞后、存储数据量大、无交互性等方面的不足．应用计算机图形学中的粒子系统来模拟流场，通过分析粒子的存储结构和出生、发展、消亡的生命历程对流场模拟的实时性和模拟效果的影响，从显示方面提高了系统运行的实时性与真实性；采用调整显示时间的方式实现计算和显示时间同步及数据的实时传输，开发了集实时计算和显示于一体的流场模拟系统。     

实时数据库系统中数据压缩技术的研究

实时数据库系统是对时间要求非常高的系统,而企业所集成的数据采集点数通常有几千到十几万个,数据采集时间间隔达秒级,数据量很大,因而数据压缩技术在实时数据库系统中尤为重要。采用基于变化率的矢量压缩和选择适当的动态压缩偏差参数使数据压缩率明显提高,有力地保证了实时数据库系统的时间特性,给企业的生产和管理带来很大的变化,提高了企业的生产率和经济效益。     

电炉流程的物流管制之三——上钢三厂大电炉分厂生产调度的实时系统仿真模型

在分析上钢三厂大电炉分厂的生产系统基础上，建立了电炉－－连铸车间生产调度的实时仿真模型，并对模型运行结果进行了说明，进而提出物流管制的目标和方法。     

复杂地区三维地震资料拼接中的一致性处理技术

在复杂地区三维地震资料拼接中,一致性处理是关键技术之一,其效果对成像质量影响重大.阐述了基于地震信号运动学和动力学特征的一致性处理技术,其基本原理是,首先对各区块地震数据进行精细速度分析和精确静校正处理;然后应用剩余振幅分析补偿值对拼接数据进行振幅一致性处理,使两个工区地震数据的均方根振幅达到同一水平;再通过子波处理技术对相邻区块的地震数据进行相位一致性处理,使地震数据的相位达到一致;最后通过地表一致性反褶积对整个工区的地震数据进行波形一致性处理.通过以上处理,保证了地震数据的运动学特征和动力学特征一致.与常规三维地震资料拼接处理技术相比,在复杂地区三维地震资料拼接处理中,该一致性处理技术可以最小化各区块地震资料之间的品质差异和边界影响.     

A Supervisory Control Method for Ensuring the Conformance of Real-Time Discrete Event Systems

In this article, we study the problem of controlling a plant described as a real-time discrete event system. The aimed objective is to ensure a conformance relation denoted tioco between the plant and the formal specification of the system, by means of a supervisor. We adopt a two-step approach. In Step 1, we express the problem into a non-real-time form, by using a transformation of timed automata (TA) into particular finite state automata called Set-Exp-Automata (SEA). The latter use two additional types of events, Set and Exp. And in Step 2, we propose a non-real-time control method suitable for SEA. We also propose a control architecture.     

Twin-bus-controller protocol for fibre optic networks

A new Data Link Layer protocol, named the Twin-Bus-Controller (TBC) protocol, is proposed for a fibre optic network with unidirectional bus topology. The TBC protocol operates on a contention-based, time-division multiplexing scheme, and is managed by two centralized bus controllers. These controllers, which also function as network managers cooperate with each other to control and coordinate the activities on the twin bus. The IBC protocol has the capability to perform at a very high network utilization, and uses simple hardware at all stations except the two bus controllers. This arrangement provides a relatively inexpensive means to accommodate a large number of stations. Heterogeneous data consisting of real-time sensor and control signals, voice and video data, and non-real-time data such as those due to accounting and administration, can be simultaneously handled by the TBC protocol. The TBC protocol maintains global queues for all different types of data, and each class of data has a bounded delay. Furthermore, any new type of data can be added easily to the network without shutting it down or affecting those stations that are unrelated to the new data. A finite-state-machine model has been used to describe the TBC protocol. Performance of the TBC protocol has been evaluated by statistical analysis as well as via simulation for multiple classes of data traffic. Performance of the TBC protocol has been compared with that of Buzznet and Fasnet. The TBC protocol can be directly applied to diverse computer communication systems, e.g. office, manufacturing, and banking environments.     

双柱塞砂浆泵补偿机构的运动分析和仿真

介绍了双柱塞砂浆泵的工作原理，通过对采用摆动滚子从动件的凸轮机构的双柱塞砂浆泵的工作凸轮机构和补偿凸轮机构进行运动学分析，建立了砂浆泵运动机构的仿真模型．用Matlab软件进行了仿真分析，进一步验证了运动学分析模型的正确性．     

单头单面旋转式化学机械抛光机的运动机理研究

以单头单面旋转式化学机械抛光机为例建立了抛光头的运动模型,并利用Matlab软件模拟出了抛光头的运动轨迹,分析并讨论了抛光盘和抛光头两者之间不同的转速比、旋转方向、偏心距以及抛光点的初始位置等参数对抛光轨迹和抛光质量的影响,为CMP机床的结构和运动设计提供理论依据。