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61.
土石过水围堰过水期最不利工况及其流量确定 总被引:7,自引:0,他引:7
本文系统分析了影响土石过水围堰溢流工况的主要因素,提出衡量最不利工况的指标和确定员不利流量的方法,为土石过水围堰堰体下游护坡结构及消能防冲设施设计提供了理论依据。通过理论计算结果与模型试验现场观测资料数据对比分析,说明提出的过水期最不利流量判别方法是符合实际情况的。 相似文献
62.
Li Yu-cheng He Ming Dept.of Civil Engineering Dalian Univ.of Technology Dalian P.R.China 《水动力学研究与进展(B辑)》1993,(4)
Based on model test,the statistical distribution of extreme values of wave-current in-line forces acting on vertical circular cylinder is analyzed in this paper.It is shownthat the results calculated by the simplified method,proposed by authors,agree well with the testdata;Weibull distribution is also adoptable in the region of high KC number, and the shapeparameter a and scale parameter β are related well with KC number respectively. 相似文献
63.
64.
BP算法的改进及用模拟电路实现的神经网络分类器 总被引:1,自引:0,他引:1
基于用模拟电路实现神经网络分类器的目的,对多层静态前馈神经网络的BP算法做了改进,采用线性限幅函数代替Sigmoid函数作为神经元的激活函数,给出了改进的BP算法。对该算法性能的实验研究表明:这种改进算法不但方便了用线性模拟集成运算放大电路实现神经网络,而且具有学习速度快,映射能力强等优点。根据本文算法设计的神经网络分类器,无论是计算机仿真,还是模拟电路实现,都得到了比较高的识别率。 相似文献
65.
Takeshi Nakajo 《Quality and Reliability Engineering International》1993,9(2):111-119
Work system improvements are implemented in various manufacturing processes to prevent problems caused by human errors. However, they are almost always applied to problems which have already occurred. This paper examines a method of identifying latent human errors existing within the work systems beforehand. A procedure for applying failure mode and effect analysis to this identification problem was defined based on over 1000 empirical errors: a work system decomposition criterion and fundamental error modes for listing latent human errors, and then applied to three practical manufacturing processes in order to evaluate its effectiveness. 相似文献
66.
目前,世界上最大的计算机网络Internet网,已成为通达150多个国家的国际互联网络。作为引导中国计算机用户进入Internet的中国公用计算机互联网CHINANET也正迅速发展。本文就Internet网的服务方式和入网方式进行了综述。 相似文献
67.
A mixed mode digital/analog special purpose VLSI hardware implementation of an associative memory with neural architecture is presented. The memory concept is based on a matrix architecture with binary storage elements holding the connection weights. To enhance the processing speed analog circuit techniques are applied to implement the algorithm for the association. To keep the memory density as high as possible two design strategies are considered. First, the number of transistors per storage element is kept to a minimum. In this paper a circuit technique that uses a single 6-transistor cell for weight storage and analog signal processing is proposed. Second, the device precision has been chosen to a moderate level to save area as much as possible. Since device mismatch limits the performance of analog circuits, the impact of device precision on the circuit performance is explicitly discussed. It is shown that the device precision limits the number of rows activated in parallel. Since the input vector as well as the output vector are considered to be sparsely coded it is concluded, that even for large matrices the proposed circuit technique is appropriate and ultra large scale integration with a large number of connection weights is feasible. 相似文献
68.
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70.
Pai H. Chou Jinfeng Liu Dexin Li Nader Bagherzadeh 《Design Automation for Embedded Systems》2002,7(3):205-232
Power-aware systems are those that must exploit a widerange of power/performance trade-offs in order to adapt to the power availabilityand application requirements. They require the integration of many novel powermanagement techniques, ranging from voltage scaling to subsystem shutdown.However, those techniques do not always compose synergistically with eachother; in fact, they can combine subtractively and often yield counterintuitive,and sometimes incorrect, results in the context of a complete system. Thiscan become a serious problem as more of these power aware systems are beingdeployed in mission critical applications.To address the problem of technique integration for power-aware embedded systems, we propose a new design tool framework called IMPACCT and the associated design methodology. The system modeling methodology includes application model for capturing timing/powerconstraints and mode dependencies at the system level. The tool performs power-awarescheduling and mode selection to ensure that all timing/power constraintsare satisfied and that all overhead is taken into account. IMPACCT then synthesizesthe implementation targeting a symmetric multiprocessor platform. Experimentalresults show that the increased dynamic range of power/performance settingsenabled a Mars rover to achieve significant acceleration while using lessenergy. More importantly, our tool correctly combines the state-of-the-arttechniques at the system level, thereby saving even experienced designersfrom many pitfalls of system-level power management. 相似文献