共查询到20条相似文献,搜索用时 8 毫秒
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汽油喷射发动机电子控制系统 总被引:3,自引:0,他引:3
对汽油喷射发动机电子控制系统进行了剖析研究,阐明了电控系统的组成、单片机控制单元的电路特点、控制原理和控制软件。电子控制使汽车发动机的动力性能、经济性和排放污染得到了很大的改善。 相似文献
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Cooling Load Density Analysis and Optimization for an Endoreversible Air Refrigerator 总被引:2,自引:0,他引:2
Shengbing Zhou Lingen Chen Fengrui Sun Chih Wu 《Open Systems & Information Dynamics》2001,8(2):147-155
The performance analysis and optimization of an endoreversible air refrigerator is carried out by taking the cooling load density, which is defined as the ratio of cooling load to the maximum specific volume in the cycle, as the optimization objective in this paper. The results obtained are different from those with the cooling load objective. Numerical examples show the effects of pressure ratio and allocation of heat exchanger inventory on the cooling load density of the refrigerator. 相似文献
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UAV集电子设备于一身,其最大射频电磁干扰(EMI)源自发动机点火系统,它不同程度地影响着机载计算机、自动驾驶仪等以及不同任务载荷的正常工作;通过对某UAV发动机研制的电容放电式点火系统(CDI)的电路和布局描述,研讨了屏蔽对其二次回路影响的机理,合理确定了工程路径,并研究出一种阻尼-屏蔽法实施在CDI中,降低点火系统EMI近20dB,同时不影响其可靠性;本研究的成功,使长期困扰CDI的EMI深入抑制取得了进步。 相似文献
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合成信息系统与子信息系统 总被引:4,自引:0,他引:4
本文给出了对象合成信息系统、属性合成信息系统、对象子信息系统及属性子信息系统的定义,分别讨论了它们的上下近似算子与原信息系统的上下近似算子之间的关系.并给出了它们的一些实际应用。 相似文献
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提出一种针对选择自动重传(SR-ARQ)技术结合自适应调制系统(AMS)的跨层分析和设计方法.该方法采用有限状态马尔可夫链(FSMC),同时对物理层和链路层进行建模,然后用更新报酬(renewal-reward)理论对系统的有效吞吐量进行精确分析,并根据分析结果设计系统中所使用的参数.计算机仿真结果验证了该跨层分析方法的精确性,并可以从中看出本方法对系统参数选取的指导意义. 相似文献
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两个小额电子支付系统的性能评估 总被引:3,自引:0,他引:3
小额电子支付系统具有很强的现实意义。详细介绍了两个比较典型的系统:Paywords,SAS-Coin,并从计算量、通信量和安全性等方面对它们的性能进行了评估和分析。 相似文献
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合成信息系统与子信息系统的属性特征 总被引:1,自引:0,他引:1
数据库的合成和分解在实际应用中是一个很重要的问题,它所对应的数学模型就是信息系统的合成与分解,该文给出了对象合成信息系统、属性合成信息系统、对象子信息系统及属性子信息系统的定义,讨论了合成信息系统、子信息系统与原信息系统等属性特征之间的关系。 相似文献
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Qin Xiaoyong Chen Lingen Sun Fengrui Wu Chih 《Open Systems & Information Dynamics》2004,11(2):147-159
Based on an endoreversible absorption heat-transformer cycle model operating between four temperature levels with linear (Newtonian) heat transfer law, the fundamental optimal relation between the specific heating load and the coefficient of performance, the optimal temperatures of the working substance, and the optimal heat transfer surface areas of the four heat exchangers are derived by using finite-time thermodynamics. Moreover, the effects of the cycle parameters on the cycle characteristic are studied by numerical examples. The results obtained herein can provide some guidance for the optimal design of absorption heat-transformers. 相似文献
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This paper describes two classifier systems that learn. These are rule-based systems that use genetic algorithms, which are based on an analogy with natural selection and genetics, as their principal learning mechanism, and an economic model as their principal mechanism for apportioning credit. CFS-C is a domain-independent learning system that has been widely tested on serial computers. CFS is a parallel implementation of CFS-C that makes full use of the inherent parallelism of classifier systems and genetic algorithms, and that allows the exploration of large-scale tasks that were formerly impractical. As with other approaches to learning, classifier systems in their current form work well for moderately-sized tasks but break down for larger tasks. In order to shed light on this issue, we present several empirical studies of known issues in classifier systems, including the effects of population size, the actual contribution of genetic algorithms, the use of rule chaining in solving higher-order tasks, and issues of task representation and dynamic population convergence. We conclude with a discussion of some major unresolved issues in learning classifier systems and some possible approaches to making them more effective on complex tasks. 相似文献
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正则表达式具有强大的描述能力,在计算机领域,正则表达式匹配技术应用十分广泛。目前,已经有多个正则表达式匹配引擎,在实际应用中,对于不同的匹配规则集和正则语法,不同的匹配引擎会有不同的性能表现。本文通过对PCRE、Greta、Boost、RE2四种常用正则表达式匹配引擎的性能测试,给出在不用的正则语法情况下的匹配速度,并深入分析不同坏境下适用的正则表达式匹配引擎。对实际系统设计中正则表达式库的选择有指导意义。 相似文献
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介绍搜索引擎的查询服务工作原理.通过网络拓扑分析、路由分析等方法,研究查询服务对网络流量的影响.由此搭建网络流量估算模型,做到对网络性能瓶颈的准确预测,在对该模型进行有针对性的测试后.提出可以更有效地解决网络性能方面问题的搜索引擎数据中心网络部署方案.保证网络设备能满足搜索引擎性能需求。 相似文献
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《Advanced Robotics》2013,27(9-10):1349-1361
In recent years, Japanese society has been aging, creating a shortage of young workers. Robots are expected to be useful to perform tasks such as rehabilitation therapy, nursing elderly people and day-to-day work support for elderly people. In particular, robots that are designed for use in the fields of medical care and welfare must be safe for the human environment because they often come into contact with humans. Furthermore, robots must have dexterity that is similar to that of humans. Under these circumstances, tendon-driven systems of two types using flexible silicone rubber materials have been developed. They are lightweight and have characteristics resembling those of human muscle. This paper describes the basic features and mechanisms of two tendon-driven systems that we have developed as a soft actuator. Furthermore, basic properties of the system are evaluated and compared with those of human muscles. 相似文献
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J. C. Chimal-Eguía M. A. Barranco-Jiménez F. Angulo-Brown 《Open Systems & Information Dynamics》2006,13(1):43-53
A local stability study of an endoreversible Stefan-Boltzmann (SB) engine, working in a maximum-power-like regime, is presented.
This engine consists of a Carnot engine that exchanges heat with heat reservoirs T1 and T2, (T1 > T2) through a couple of thermal links, both having the same conductance g. In addition, the working fluid has the same heat capacity C in the two isothermal branches of the cycle. From the local stability analysis we conclude that the SB engine is stable for
every value of g, C and τ = T2/T1. After a small perturbation, the system decays to the steady state with either of two different relaxation times; both being
proportional to C/g, and τ. Finally, when we plot some of the thermodynamic properties in the steady state versus τ, we find how an increment of τ can improve the stability of the system, at the same decreasing the efficiency and the power of the system. This suggests
a compromise between the stability and the energetic properties of the engine driven by τ. 相似文献
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广义系统的两个不确定型的脉冲控制 总被引:5,自引:2,他引:3
本文讨论了广义系统的两种不确定型Ex=(A+δA)x+Bu(t),y(t)=Cx(t),Ex(t)=(A+δA)x(t)+(B+δB)u(r),y(t)=(C+δC)x(t)的脉冲控制,其中δA,δB,δC都是不确定量,在一定条件下给出了脉冲控制器的构造方法. 相似文献
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线性多变量系统的联合辨识算法 总被引:3,自引:1,他引:2
本文提出了同时估计线性多变量系统所有参数的联合辨识算法(CIA),并用随机过程理论分析了算法的收敛性。与子系统辨识算法(SSIA)相比,CIA的计算量要小得多。各输出间存在相互作用噪声时的辨识问题通过使用递推广义增广最小二乘法(RGELA)得到解决。数字仿真结果表明了CIA的有效性。 相似文献
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在视频监控的运动检测中,由于光照、风吹等影响,运动阴影常常被误认为运动对象。为了有效解决动态背景下运动目标中存在的阴影问题,提出了一种归一化的RGB颜色空间和HSV颜色空间相结合的阴影消除方法。该方法首先在归一化RGB颜色空间下用背景减除法得到运动目标,然后在HSV空间下对阴影进行检测和消除,从而得到真实运动目标。实验结果证实:该方法在运动目标检测及跟踪方面取得了较好的效果,对动态背景的视频,能准确、实时地检测出阴影并进行消除。 相似文献