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11.
A comparison is made of a differential-competitive-learning (DCL) system with two supervised competitive-learning (SCL) systems for centroid estimation and for phoneme recognition. DCL provides a form of unsupervised adaptive vector quantization. Standard stochastic competitive-learning systems learn only if neurons win a competition for activation induced by randomly sampled patterns. DCL systems learn only if the competing neurons change their competitive signal. Signal-velocity information provides unsupervised local reinforcement during learning. The sign of the neuronal signal derivative rewards winners and punishes losers. Standard competitive learning ignores instantaneous win-rate information. Synaptic fan-in vectors adaptively quantize the randomly sampled pattern space into nearest-neighbor decision classes. More generally, the synaptic-vector distribution estimates the unknown sampled probability density function p( x). Simulations showed that unsupervised DCL-trained synaptic vectors converged to class centroids at least as fast as, and wandered less about these centroids than, SCL-trained synaptic vectors did. Simulations on a small set of English phonemes favored DCL over SCL for classification accuracy. 相似文献
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关于加强财务管理,提高经济效益的思考 总被引:1,自引:0,他引:1
随着我国经济改革的不断深入,我局的经济工作也从单一的地质勘查向经济多元化方面发展,并且取得了可喜的成果,仅去年我局的多经产值就上亿元,经济规模比上世纪末又上了一个台阶.但我们同时又看到,经济规模虽已扩大,而效益却不尽如人意,虽有利润但微乎其微,有些甚至出现负数.是什么原因使之我们的经济状况总是停留在维持简单再生产上呢?其中原因虽有客观上的,比如:承揽的工程项目单价太低,业务量不饱满,安置人员任务较重等等.但主观原因我认为我们的成本管理还是不到位,“跑、冒、滴、漏”现象严重,这就给我们的财务管理提出了一个严竣的问题,财务应如何管理才能为经济效益的提高发挥其作用呢?我想就这个问题谈谈自己的一些看法和想法. 相似文献
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氨合成塔出口氨含量偏低原因分析及对策 总被引:1,自引:0,他引:1
阐述UHDE合成塔运行现状 ,分析氨净值达不到设计值的原因 ,提出相应的解决措施 相似文献
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Shumin Zhai Jing Kong Xiangshi Ren 《International journal of human-computer studies》2004,61(6):823-856
Pointing tasks in human–computer interaction obey certain speed–accuracy tradeoff rules. In general, the more accurate the task to be accomplished, the longer it takes and vice versa. Fitts’ law models the speed–accuracy tradeoff effect in pointing as imposed by the task parameters, through Fitts’ index of difficulty (Id) based on the ratio of the nominal movement distance and the size of the target. Operating with different speed or accuracy biases, performers may utilize more or less area than the target specifies, introducing another subjective layer of speed–accuracy tradeoff relative to the task specification. A conventional approach to overcome the impact of the subjective layer of speed–accuracy tradeoff is to use the a posteriori “effective” pointing precision We in lieu of the nominal target width W. Such an approach has lacked a theoretical or empirical foundation. This study investigates the nature and the relationship of the two layers of speed–accuracy tradeoff by systematically controlling both Id and the index of target utilization Iu in a set of four experiments. Their results show that the impacts of the two layers of speed–accuracy tradeoff are not fundamentally equivalent. The use of We could indeed compensate for the difference in target utilization, but not completely. More logical Fitts’ law parameter estimates can be obtained by the We adjustment, although its use also lowers the correlation between pointing time and the index of difficulty. The study also shows the complex interaction effect between Id and Iu, suggesting that a simple and complete model accommodating both layers of speed–accuracy tradeoff may not exist. 相似文献
16.
Flame retardant and the degradation mechanism of high impact polystyrene/Fe-montmorillonite nanocomposites 总被引:1,自引:1,他引:0
High impact polystyrene/Fe-montmorillonite (HIPS/Fe-MMT) nanocomposites were successfully prepared by melting intercalation.
The nanostructures of HIPS/Fe-MMT were testified by X-ray diffraction (XRD) and transmission electron microscope (TEM). Corresponding
to pure HIPS, the thermal stability of HIPS/Fe-MMT nanocomposites was notably improved. The peaks of heat release rate (PHRR)
and the mass loss rate (MLR) were significantly reduced after the formation of the HIPS/Fe-MMT nanocomposites from cone calorimetry.
And nanocomposites PHRR was further lower with the increase of Fe-MMT content in the range of 1 to 5 wt%. The degradation
mechanism of HIPS and HIPS/Fe-MMT nanocomposites was conducted by pyrolysis gas chromatography mass spectrometry (Py-GC-MS).
And the reason of the enhancement of thermal stability maybe is that structural iron is the operative site for radical trapping
in the Fe-MMT and the nanostructure enhances the interaction of the chains of the HIPS. 相似文献
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通过在三种不同的强化负荷下进行深沟球轴承疲劳寿命试验,并与常规试验一组结果对比。结果表明,适当地加大滚动轴承疲劳寿命试验负荷,可以大大缩短试验时间,而疲劳寿命依然服从Weibul分布,且与常规试验结果基本一致,同时疲劳破坏的形式仍是表面下萌生裂纹,然后扩展至表面形成剥落。 相似文献
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