Modeling and optimization of semiconductor manufacturing process with neural networks

A neural network-based process model is proposed to optimize the semiconductor manufacturing process. Being different from some works in several research groups which developed neural network-based models to predict process quality with a set of process variables of only single manufacturing step, we applied this model to wafer fabrication parameters control and wafer lot yield optimization. The original data are collected from a wafer fabrication line, including technological parameters and wafer test results. The wafer lot yield is taken as the optimization target. Learning from historical technological records and wafer test results, the model can predict the wafer yield. To eliminate the "bad" or noisy samples from the sample set, an experimental method was used to determine the number of hidden units so that both good learning ability and prediction capability can be obtained.

从字形到语义：跨语言Stroop效应的ERP研究

According to the influential dual-route model of reading (Coltheart, Rastle et al. 2001), there are two routes to access the meaning of visual words: one directly by orthography (orthography-semantic) and the other indirectly via the phonology (phonology-semantic). Because of the dramatic difference between written Chinese and alphabetical languages, it is still on debate whether Chinese readers have the same semantic activation processes as readers of alphabetical languages. In this study, the semantic activation processes in alphabetical German and logographic Chinese were compared. Since the N450 for incongruent color words in the Stroop tasks was induced by the semantic conflict between the meaning of the incongruent color words and color naming, this component could be taken as an index for semantic activation of incongruent color words in Stroop tasks. Two cross-script Stroop experiments were adopted to investigate the semantic activation processes in Chinese and German. The first experiment focused on the the role of phonology, while the second one focused on the realative importance of orthography. Cultural differences in cognitive processing between individuals in western and eastern countries have been found (Nisbett & Miyamoto, 2005). In order to exclude potential differences in basic cognitive processes like visual discrimination capabilities during reading, a visual Oddball experiment with non-lexical materials was conducted with all participants. However, as indicated by the P300 elicited by deviant stimuli in both groups, no group difference was observed. In the first Stroop experiments, color words (e.g., “green”), color-word associates (e.g., “grass”), and homophones of color words were used. These words were embedded into color patches with either congruent color (e.g. word “green” in green color patch) or incongruent colors (e.g. word “green” in either red or yellow or blue color patch). The key point is to observe whether homophones in both languages could induce similar behavioral and ERP Stroop effects to that induced by color words. It was also interesting to observe to which extent the N450 was related to the semantic conflicts. Nineteen Chinese adult readers and twenty German adult readers were asked to respond to the back color of these words in the Stroop experiment in their native languages by pressing the corresponding keys. In the behavioral data, incongruent conditions (incongruent color words, incongruent color-word associates, incongruent homophones) had significantly longer reaction times as compared to corresponding congruent conditions. All incongruent conditions in the Geman group elicited an N450 in the 400 to 500 ms time window. In the Chinese group, the N450 in the same time window was also observed for the incongruent color words and incongruent color-word associates. These results indicated that the N450 was very sensitive to semantic conflict-even words with semantic association to colors (e.g. “grass”) could elicite similar N450. However, the N450 was absent for incongruent homophones of color words in the Chinese group. Instead, in a later time window (600-800 ms), incongruent homophones elicited a positivity over left posterior regions as compared to congruent homophones. Similar positivity was also observed for color words in the 700 to 1000 ms time window in the Chinese group and 600 to 1000 ms time window for incongruent color words and homophones in the Geman group. These results indicate that phonology plays an important role in Geman semantic activation processes, but not in Chinese. In the second Stroop experiment, color words and pseudowords which had similiar visual shape to color words in both languages were used as materials. Another group of eighteen Chinese and twenty Germans were involved in the Stroop experiment in their native languages.The ERPs were recorded during their performance. In the behavioral data, strong and comparable Stroop effects (as counted by substract the reaction times in the congruent conditions from reaction times in the incongruent conditions) were observed. In the ERP data, both incongruent color words and incongruent pseudowords elicited an N450 over the whole brain scalp in both groups. These results indicated that orthography played an equally important role in semantic activation processes in both languages. The results of the two Stroop experiments support the view that the semantic activation process in Chiense readers differs significantly from that in German readers. The former rely mainly on the direct route (orthography-semantic), while the latter use both direct route and incirect route (phonology-semantic). These findings also indicate that the characteritics of different languages shape the semantic activation processes.

Numerical Simulation of Heat Transfer and Kinetics in the Bulk Growth of Silicon Carbide

The growth process of 2-inch silicon carbide (SiC) single crystals by the physical vapor transport method (or modified Lely method) has been modeled and simulated. The comprehensive process model incorporates the calculations of radio frequency (RF) induction heating, heat and mass transfer and growth kinetics. The transport equations for electromagnetic field, heat transfer, and species transport are solved using a finite volume-based numerical scheme called MASTRAPP (Multizone Adaptive Scheme for Transport and Phase Change Process). Temperature distribution for a 2-inch growth system is calculated, and the effects of induction heating frequency and current on the temperature distribution and growth rate are investigated. The predicted results have been compared with the experimental data.

一种基于Agent的自适应软件过程模型

传统的软件过程模型大多是静态的、机械的、被动的,它们要求软件工程人员在描述软件过程时预期所有可能发生的情况,并且显式地定义这些问题的解决方案.当软件过程所处的环境发生变化时,软件过程无法自适应地对这些变更作出相应的调整.提出了一种基于Agent的自适应软件过程模型.在这种软件过程模型中,软件过程被描述为一组相互独立而对等的实体——软件过程Agent.这些软件过程Agent能够对软件过程环境的变化主动地、自治地作出反应,动态地确定和变更其行为以实现软件开发的目标.

一种基于模型融合的CMM实施过程建模方法

提出了一种基于模型融合的CMM实施过程建模方法.该方法使用软件过程工程元模型SPEM建立CMM过程模型CPM和企业过程模型EPM,通过融合CPM和EPM来获得CMM实施过程模型C IPM.文中利用带标记的有向图描述过程模型,给出了模型融合方法,并进行了一致性证明.最后通过一个过程模型融合原型工具和实例说明了方法的应用情况.

基于模拟的企业过程模型自动优化技术研究

企业过程模型参数自动优化是一个多参数多目标的系统优化问题.采用线性加权法将其转换成多参数单目标问题的求解,提出基于计算机模拟的企业过程模型参数的自动寻优方法.它将传统的共轭梯度法FR（fletcher reeves）和禁忌搜索算法TS（tabu search）结合起来,采用FR法进行局部寻优,由TS法实现从当前局部最优点向全域范围内的更优区域转移,循环往复达到求出全域范围最优点的目的.改进了FR法与TS法,克服了各自的缺陷,并提出禁忌区域表的概念,从而加速寻优过程.它适用于任意多维曲面的多极值问题最优求解,对企业进行BPR（business process reengineering）和实施ERP（enterprise resource planning）管理有较大的指导意义.

一种基于XML的工作流过程模型的设计和实现

1.引言面对数字经济时代带来的不断增长的竞争压力,企业逐步寻求新的商业运作模式以适应这种变化。随着信息技术和Internet技术的迅猛发展,为适应这种变化提供了条件。企业不再满足于孤立、零散的办公自动化和计算机应用,而是需要综合的、集成化的解决方案。作为一种对常规性事务进行管理、集成的技术,工作流管理系统(Workflow ManagementSystem,WMS)的出现是必然的。如何建立企业业务过程模型是工作流管理系统的核心问题。

A laboratory study of rheological properties of mudflows in Hangzhou Bay, China

A laboratory study of the rheology of mudflows in Hangzhou Bay, China, is reported in this paper. Both the steady and oscillatory (dynamic) rheological properties are studied using RMS-605 rheometer. A Dual-Bingham model is proposed for analyzing flow curves and compared with Worrall-Tuliani model. It is found that Dual-Bingham plastic rheological model is easier to implement than Worrall-Tuliani model and can provide satisfactory representations of the steady mudflows in Hangzhou Bay and other published data. The dependence of the yield stress and viscosity on sediment concentration is discussed based on the data from Hangzhou Bay mud and other published data. For the dynamic rheological properties of Hangzhou Bay mud, empirical expressions for elastic modulus and dynamic viscosity are provided in the form of exponential functions of sediment volume concentration, and comparisons with other published data also discussed.

用计算机辅助创新软件解决产品技术创新问题的研究

本文简要介绍了发明问题解决理论TRIZ和机算机辅助创新软件Pro/Innovator的主要内容,建立了基于创新理论TRIZ和CAI软件的创新问题解决流程模型,作为特例建立了Pro/Innovator1.0的简化流程图,最后用软件完成了一个工程实例问题的创新设计。

基于智能可重构装配线制造系统的产品装配序列规划研究

研究了基于智能装配单元的可重构装配线制造系统环境中的产品装配建模方法与装配序列表达机制,提出由产品层次装配模型与生产线装配工艺齿状结构描述相结合的重构装配线装配序列规划与表达方法。

基于PMAC开放式数控系统软件开发

基于PC和多轴运动控制器的开放式数控系统是理想的开放式数控系统。介绍了基于PMAC的开放式数控系统结构形式,PMAC的差补、位置控制、伺服功能、以PMAC和PC机为硬件平台搭建了数控系统,并对其硬件构成和软件设计结构进行了分析。着重从软件设计的角度,介绍了PTALK控件的功能和作用,对数控系统软件构成进行了详细的阐述。并设计出了友好的用户界面,在实际应用中具有重要意义。

卷烟厂制丝线生产过程建模与计划仿真

对当前卷烟厂制丝线计划与调度管理中存在的不足进行了介绍,并在建立制丝生产线生产过程模型的基础上,提出了用于解决问题的计划仿真系统,对所采用的仿真策略进行了详细介绍。采用这一策略实现的仿真系统能够很方便的适应于其他行业类型的仿真。