COM技术在电力系统图形生成子系统中的应用

COM(ComponentObjectModel)技术是一种新的软件开发方法 ,它提供了跨越编程语言、操作系统甚至网络来访问组件对象的通用途径。在阐述其基本概念、特点和实现方法的基础上 ,讨论了COM技术在电力系统图形生成子系统中的应用 ,使图形子系统的开发在最大程度上实现了软件复用。基于该方法开发的图形子系统已在电力系统倒闸操作票系统中得到实际应用     

基于Web机制的作业管理系统的设计与实现

传统的作业管理系统一般局限在局域网范围内，用户量有限，作业的执行状态和结果不能通过Internet网远程监控和查询。文章在考察Web技术的基础上设计并实现了一种基于Web机制的作业管理系统，文中阐述了系统的应用模式和体系结构，以及系统中各个子系统的功能及相互关系，引入了作业网络的概念，描述了作业间复杂的逻辑依赖关系，也可表达作业网络间的层次和嵌套关系，这进一步扩大了系统的应用领域。     

松辽盆地北部沙河子组-登二段含气子系统评价

利用气势能场的分隔槽,将松辽盆地北部沙河子组—登二段含气系统划分为8个含气子系统。选取源岩、储层、盖层、圈闭和运移以及盖层与源岩、断裂活动与源岩、圈闭与源岩之间的时间匹配关系分别作为含气子系统综合评价指标。通过划分等级、赋予权值、计算综合评价权值建立了一套含气子系统的综合评价方法,并对松辽盆地北部沙河子组—登二段含气系统的8个含气子系统进行了综合评价。结果表明,古龙、安达南—昌五、肇州—肇源和双城—呼兰含气子系统为好的含气子系统,是天然气勘探的有利地区。古龙北和朝长—肇东南含气子系统为较好的含气子系统,是天然气勘探的较有利地区。     

CPLD在电脑横机控制器中的应用

电脑横机的核心部分是其整机控制系统,有两百多路I/O信号,控制起来相当复杂.若使用传统的器件(例如8255)实现这两百多路I/O集中接入主处理器,集成度会很低,稳定性也不好.提出一种基于CPLD的实现方法,构建其中的工艺执行子系统,代替多块8255器件的互联,实践证明它具有集成度高,稳定性好的优点.一方面软件层的许多工作可以适当下移到CPLD中,由硬件实现,控制更有效;另一方面,CPLD器件的可重复编程的特性也为系统提供了很好的可移植性.     

非线性系统受随机激励的动力响应分析

利用线性系统脉冲响应函数的概念,采用矩阵摄动法对非线性系统受随机激励的响应进行分析,得到了求解此类问题的一般途径,给出算例,并讨论了其可信度和精度     

基于JMS的系统工具子系统的设计与实现

研究了JMS（Java message service）的基本原理和消息传递模式,并给出了基于JMS的系统工具子系统的设计和实现方案.网管后台系统中,利用JMS技术来实现消息的异步通信,极大提高了系统性能,使系统更健壮、更灵活.     

汽车振动噪声（NVH）控制——汽车工业面临的新问题

汽车NVH（Noise,Vibration,Harshness）特性是汽车五大重要性能之一,是汽车行业与相关汽车零部件行业关注的综合性问题。本文分析了车内振动、噪声的产生原因及传递路径,并给出了汽车主要的减振、降噪、密封零部件（如动力总成悬置、底盘衬套、悬架系统、筒式减振器等）的结构形式,工作原理、发展趋势等,并展望了汽车NVH控制技术的发展前景。     

优特钢冷床上钢系统的优化与改造

分析轧钢厂优特钢冷床上钢系统存在的问题,提出有效的技术改造措施,确保冷床上钢装置动作正常稳定.     

Performance of RAID5 disk arrays with read and write caching

In this paper, we develop analytical models and evaluate the performance of RAID5 disk arrays in normal mode (all disks operational), in degraded mode (one disk broken, rebuild not started) and in rebuild mode (one disk broken, rebuild started but not finished). Models for estimating rebuild time under the assumption that user requests get priority over rebuild activity have also been developed. Separate models were developed for cached and uncached disk controllers. Particular emphasis is on the performance of cached arrays, where the caches are built of Non-Volatile memory and support write caching in addition to read caching. Using these models, we evaluate the performance of arrayed and unarrayed disk subsystems when driven by a database workload such as those seen on systems running any of several popular database managers. In particular, we assume single-block accesses, flat device skew and little seek affinity.With the above assumptions, we find six significant results. First, in normal mode, we find there is no difference in performance between subsystems built out of either small arrays or large arrays as long as the total number of disks used is the same. Second, we find that if our goal is to minimize the average response time of a subsystem in degraded and rebuild modes, it is better to use small arrays rather than large arrays in the subsystem. Third, we find the counter-intuitive result that if our goal is to minimize the average response time of requests to any one array in the subsystem, it is better to use large arrays than small arrays in the subsystem. We call this the best worst-case phenomenon.Fourth, we find that when no caching is used in the disk controller, subsystems built out of arrays have a normal mode performance that is significantly worse than an equivalent unarrayed subsystem built of the same drives. For the specific drive, controller, workload and system parameters we used for our calculations, we find that, without a cache in the controller and operating at typical I/O rates, the normal mode response time of a subsystem built out of arrays is 50% higher than that of an unarrayed subsystem. In rebuild mode, we find that a subsystem built out of arrays can have anywhere from 100% to 200% higher average response time than an equivalent unarrayed subsystem.Out fifth result is that, with cached controllers, the performance differences between arrayed and equivalent unarrayed subsystems shrink considerably. We find that the normal mode response time in a subsystem built out of arrays is only 4.1% higher than that of an equivalent unarrayed system. In degraded (rebuild) mode, a subsystem built out of small arrays has a response time 11% (13%) higher and a subsystem built out of large arrays has a response time 15% (19%) higher than an unarrayed subsystem.Our sixth and last result is that cached arrays have significantly better response times and throughputs than equivalent uncached arrays. For one workload, a cached array with good hit ratios had 5 times the throughout and 10 to 40 times lower response times than the equivalent uncached array. With poor hit ratios, the cached array is still a factor of 2 better in throughput and a factor of 4 to 10 better in response time for this same workload.We conclude that 3 design decisions are important when designing disk subsystems built out of RAID level 5 arrays. First, it is important that disk subsystems built out of arrays have disk controllers with caches, in particular Non-Volatile caches that cache writes in addition to reads. Second, if one were trying to minimize the worst response time seen by any user, one would choose disk array subsystems built out of large RAID level 5 arrays because of the best worst-case phenomenon. Third, if average subsystem response time is the most important design metric, the subsystem should be built out of small RAID level 5 arrays.     

可靠性工程分配法在雷达设计中的应用

在工程设计中经常要评估产品可靠性方面的指标，如失效率、平均无故障时间、平均维修时间等数值的测算和分配。总结了双基地多普勒气象雷达可靠性设计方面的一些具体工作，以及可靠性原理在其中的应用。