基于基数排序的集成服务优先队列算法

传统的服务质量(QoS)算法分为差别服务和集成服务两种,前者提供相对的服务质量保证,而后者则可以提供绝对的服务质量保证,二者最终都可以归结为优先队列算法。在核心路由器中QoS对优先队列的要求比较高,差别服务需要提供OC-768(40Gbps)线速、很大的有效排队长度和较小的最小时延。集成服务除了上述要求还需要很大的优先级数目。受到基数排序算法的启发,论文设计了一种基于基数排序的适用于集成服务的优先队列算法,具有以下特点:(1)带宽可以达到OC-768线速,优先级数目和有效排队长度不受限制,最小时延可以接受。(2)结构比较简单,不需要非常复杂的电路设计。     

通过寄存器队列模型实现寄存器分配和指令调度

寄存器分配与指令调度是编译器优化过程中的两项重要任务．由于这两个阶段通常是独立完成的，寄存器分配往往会引入不必要的伪相关，从而影响指令调度的效率和结果，影响最终性能的提高．本文提出了寄存器队列模型，并在其基础上提出了一种结合实现寄存器分配和指令调度的算法，该算法能够在保证每条指令的执行时间最早的同时使用最少数目的寄存器．它的另外一个优点是具有线性的时间和空间复杂度，而且易于硬件实现．     

用Oracle的DBMS_JOB来实现任务计划管理

介绍了运用Oracle数据库来进行计划任务管理的实现过程，包括启动任务队列管理器时Oracle的工作模式、启动参数的设置，以及利用DBMS_JOB将创建的存储过程放入Oracle的作业队列中去，由系统按时调度运行。     

利用关联规则帮助销售商选择商品的两种模型

人们对关联规则技术的理解大多局限在使用它来分析顾客的购买模式,但最近的研究却越来越侧重于对这种数据挖掘技术的经济评价。该文介绍了两个根据微观经济模式来判别关联规则的有用性,并用于销售商选择最佳商品的模型:PROFSET和HAP。并运用模拟数据对这两种模型的效率进行了比较。     

vxWorks下基于缓冲队列的全双工网络通讯

文章针对半自动大型仪器使用半双工网络通讯造成的效率下降问题,建立了在嵌入式实时操作系统vxWorks下全双工网络通讯的模式,并特别提出了双缓冲队列的流水线处理方法和通讯死时间的概念。该方法充分利用vxWorks对多任务和网络的良好支持,做到了在操作人员层面上的软件零死时间,在改善系统响应特性,提高软件效率上都很有帮助。因此比半双工通讯方式更加适用于半自动控制。     

基于令牌漏桶法的数据记录技术

针对实时系统记录数据会引起系统运行速度缓慢、瘫痪、甚至＂死机＂的问题,提出了具有特色的令牌漏桶法。该方法通过创建循环队列数据池并根据数据池的数据量适时发放令牌和拥有令牌的任务自动选择CPU空闲时执行等技术实现。通过试验验证,在保证整个系统实时性、可靠性的前提下,该方法实现了实时记录数据的功能。     

The approximation analysis of the discrete-time Geo/Geo/1 system with additional optional service

This paper analyses a discrete-time Geo/Geo/1 queueing system, where all arriving customers demand the first essential service and some of them may further demand an additional optional service. The interarrival times, the service times of the essential service and the second optional service for arrivals are assumed to be random variables with Geometric distributions. Such a model has potential applications in computer or digital communication network systems. We model this system by the level-dependent and independent quasi-birth-death processes and develop efficient computation algorithms of the stationary distribution of the number of customers in the system using matrix analytic method. A cost model is derived to determine the optimal values of the two different service rates simultaneously at the minimal total expected cost per unit time. Illustrative numerical examples demonstrate the optimization approach.     

Optimal assignment of human resources for maintenance departments using fuzzy queuing systems

Maintenance-related costs are one of the main components of overhead costs and constitute an important part of a product’s actual cost. Therefore, making proper efforts to reduce and optimise maintenance costs could be one way of gaining competitive advantages. A major part of maintenance-related costs is the salaries paid to the workforce in the maintenance department. This paper seeks the optimal assignment of human resources to the maintenance department to reduce the related costs. First, we model the maintenance department using fuzzy queue models. Then, a cost function is proposed which includes the costs of workforce shortage and workforce overload. The optimal size of workforce is obtained by considering different numbers and choosing the one which minimises the total costs. Some parameters are fuzzy outputs of the queue models, which make fuzzy results of the cost function. In order to find the minimum fuzzy cost function, we use Lee and Li fuzzy ranking method. Finally, our model is tested in a spiral-tube company and a sensitivity analysis is performed.     

A Real-Time Application of Modified Inductor Coupled KY Converter Topology in Speed Control of E-Bikes

Abstract

Congested road network and traffic jam lead to vehicle idling and fuel wastage. An E-bike which is a solution to this is often available with Thumb Throttle Mechanism and single speed operation. A motor controller with multiple output voltage levels and Click Throttle Mechanism is presented in this paper which provides variable speed operation, better power utilization and is highly economical. Proposed modified KY converter utilizes the turns ratio of an On-Line Tap Changer (OLTC) to generate multiple output voltages for variable speed commutation. This possess a stable continuous conduction mode throughout its operation and reduced switching transients when compared to the existing topologies. Mutually independent control variables namely turns ratio and duty ratio, are used here for voltage conversion, which facilitates the flexible transition between multiple output voltage levels. A 15?W prototype of the proposed modified inductor coupled KY converter is realized using Arduino Uno Board.     

连续时间完全服务与门限服务两级轮询系统性能研究

在信息分组以连续时间规律到达系统的基础上，对于轮询系统中不同优先级的业务问题，提出区分优先级的两级轮询服务模型。首先，在该模型中，低优先级站点采用门限服务，高优先级站点采用完全服务；然后，在高优先级转低优先级时，将传输服务与转移查询并行处理来降低服务器在查询转换期间所耗费的时间，提高轮询系统的效率；最后，运用马尔可夫链和概率母函数的方法建立了系统的数学模型，通过对数学模型精确解析，得到了连续时间两级服务系统每个站点的平均排队队长和平均等待时间的表达式，精确解析出平均排队队长和平均等待时间的值。仿真实验结果表明：理论计算值与实验仿真值近似相等，说明理论分析正确合理。该模型既能保障低优先级站点服务质量，又能为高优先级站点提供优质服务。