一种新的IP分组丢弃策略PRDP

该文分析了IP业务在MPLS/DiffServ上运行的特点,从考虑业务量工程性能的角度出发提出了一种新的IP分组优先级的划分方法,并在此基础上给出了一种新的IP分组丢弃算法基于优先级的丢弃策略(PBDP)。考虑到随机早检测策略(RED)的优点,将PBDP与RED相结合,得到一种改进的算法基于优先级的RED策略(PRDP),仿真结果表明这种算法在提高全网性能上有优势,其性能优于传统的尾丢弃策略。     

基于嵌入式平台的公交优先智能控制系统

系统基于公交优先智能控制策略,采用内嵌ARM9内核的三星S3C2410处理器,整合了GPS（全球定位系统）、GPRS（通用无线分组业务）以及多数据流传感器,实现对公交车辆位置、温度、人数等数据的采集、传输及反馈,提高了公交系统调度效率和增强了安全性,实现了公交优先的智能控制。介绍了系统的构成,并给出软硬件的设计方案。     

某难选铜镍矿石选矿新工艺

某难选铜镍矿石含铜0.27%、含镍0.72%,为实现矿石中铜镍矿物的综合回收与高效分离,本文采用“铜-镍优先浮选”工艺流程,以自主研发的高效铜矿物捕收剂LP-01作选铜捕收剂,石灰作抑制剂,在矿浆pH为8.5的低碱介质中优先浮选铜矿物;浮选尾矿以硫酸铜作活化剂、丁基黄药作捕收剂浮选镍矿物,获得了含铜25.35%、含镍0.79%,铜回收率80.73%的铜精矿,含镍8.15%、含铜0.23%,镍回收率75.41%的镍精矿。试验指标良好,铜、镍矿物都得到了较好的浮选回收与分离。     

Analysis for a two-dissimilar-component cold standby repairable system with repair priority

In this paper, a cold standby repairable system consisting of two dissimilar components and one repairman is studied. Assume that working time distributions and repair time distributions of the two components are both exponential, and Component 1 has repair priority when both components are broken down. After repair, Component 1 follows a geometric process repair while Component 2 obeys a perfect repair. Under these assumptions, using the perfect repair model, the geometric process repair model and the supplementary variable technique, we not only study some important reliability indices, but also consider a replacement policy T, under which the system is replaced when the working age of Component 1 reaches T. Our problem is to determine an optimal policy T^? such that the long-run average loss per unit time (i.e. average loss rate) of the system is minimized. The explicit expression for the average loss rate of the system is derived, and the corresponding optimal replacement policy T^? can be found numerically. Finally, a numerical example for replacement policy T is given to illustrate some theoretical results and the model's applicability.     

An optimal replacement policy for a repairable system based on its repairman having vacations

This paper studies a cold standby repairable system with two different components and one repairman who can take multiple vacations. If there is a component which fails and the repairman is on vacation, the failed component will wait for repair until the repairman is available. In the system, assume that component 1 has priority in use. After repair, component 1 follows a geometric process repair, while component 2 can be repaired as good as new after failures. Under these assumptions, a replacement policy N based on the failed times of component 1 is studied. The system will be replaced if the failure times of component 1 reach N. The explicit expression of the expected cost rate is given, so that the optimal replacement time N^? is determined. Finally, a numerical example is given to illustrate the theoretical results of the model.     

A DISCRETE TIME TWO-LEVEL MIXED SERVICE PARALLEL POLLING MODEL

We present a discrete time single-server two-level mixed service polling systems with two queue types,one center queue and N normal queues.Two-level means the center queue will be successive served aft...     

Contribution of combined sewer overflows to trace contaminant loads in urban streams

The present study examines the contribution of combined sewer overflows (CSO) to loads and concentrations of trace contaminants in receiving surface water. A simple method to assess the ratio of CSO to wastewater treatment plant (WWTP) effluents was applied to the urban River Spree in Berlin, Germany. The assessment indicated that annual loads are dominated by CSO for substances with removal in WWTP above ∼95%. Moreover, it showed that substances with high removal in WWTP can lead to concentration peaks in the river during CSO events. The calculated results could be verified based on eight years of monitoring data from the River Spree, collected between 2000 and 2007. Substances that are well removed in WWTP such as NTA (nitrilotriacetic acid) were found to occur in significantly increased concentration during CSO, while the concentration of substances that are poorly removable in WWTP such as EDTA (ethylenediaminetetraacetic acid) decreased in CSO-influenced samples due to dilution effects. The overall results indicate the potential importance of the CSO pathway of well-removable sewage-based trace contaminants to rivers. In particular, high concentrations during CSO events may be relevant for aquatic organisms. Given the results, it is suggested to include well-removable, sewage-based trace contaminants, a substance group often neglected in the past, in future studies on urban rivers in case of combined sewer systems. The presented methodology is suggested for a first assessment, since it is based solely on urban drainage data, which is available in most cities.     

Delta互连网有效存贮器带宽性能分析

本文运用概率分析方法，详细地分析了拥有优先级的Ｄｅｌｔａ网有效存贮器带宽的性能，获得的有效带宽模型基于访存请求均匀分布于各存贮器模块中，结果表明：优先级并不影响整个Ｄｅｌｔａ互连网有效存贮器带宽的性能。计算机模拟的结果也验证了理论分析的有效性。     

一种处理多优先级业务的新模型

从链路优先的角度来照顾高优先级业务 ,针对 3类业务的复用传输提出了一种有关链路分配的新策略。通过对新策略下信息传输系统的排队模型进行解析 ,得出了系统不同状态的概率的表达式。模拟试验表明 ,新策略可以更好地满足综合业务网络中高优先级业务的服务质量。     

A priority media access control protocol for video communication support on CSMA/CD LANs

Real-time multimedia communication applications demand performance requirements which differ significantly from conventional data communication applications. Current local area networks (LANs) provide efficient transport for bursty data traffic; however, they cannot necessarily provide quality of service guarantees for real-time communications. In this work we introduce and investigate an experimental priority protocol for supporting real-time communication on Ethernet, a popular implementation of multiple-access broadcast bus LANs. We examine the new protocol, known as Priority Mode-CSMA/CD (PM-CSMA/CD), providing a high priority (HP) class with CSMA/CD employed for standard priority (SP) traffic. PM-CSMA/CD performance is examined through computer simulation of videotelephony workstations operating over the shared bus LAN. Over all observed traffic conditions, the priority protocol provides performance satisfying real-time packet transport requirements of audio and video streams. The primary advantage of our protocol over similar priority schemes is its physical layer compatibility with standard CSMA/CD. The protocol also provides improved channel utilization with increasing high priority load, with no penalty in SP class performance at low to medium network loads.