A cascaded neuro-computational model for spoken word recognition

In human speech recognition, words are analysed at both pre-lexical (i.e., sub-word) and lexical (word) levels. The aim of this paper is to propose a constructive neuro-computational model that incorporates both these levels as cascaded layers of pre-lexical and lexical units. The layered structure enables the system to handle the variability of real speech input. Within the model, receptive fields of the pre-lexical layer consist of radial basis functions; the lexical layer is composed of units that perform pattern matching between their internal template and a series of labels, corresponding to the winning receptive fields in the pre-lexical layer. The model adapts through self-tuning of all units, in combination with the formation of a connectivity structure through unsupervised (first layer) and supervised (higher layers) network growth. Simulation studies show that the model can achieve a level of performance in spoken word recognition similar to that of a benchmark approach using hidden Markov models, while enabling parallel access to word candidates in lexical decision making.     

基于语音识别技术的刀具工况在线监测的研究

分析了刀具在线监测研究概况,提出了基于语音识别技术的刀具工况在线监测方法.实验结果表明,刀具切削声谱特征与其磨损情况之间具有对应关系,刀具磨损的工况信息与所产生的声信号具有同步效应,可以实时地获得监测信息,预先发现故障或危险.为刀具工况监测提供一种新的有效方法.     

基于混合特征LLE融合与SVM的质量异常模式识别

针对生产过程中存在的异常模式识别的问题,提出基于LLE融合与支持向量机的质量异常模式识别方法。首先从动态数据流中提取其原始特征、统计特征、几何特征并将其进行混合,形成动态数据流的混合特征,然后利用LLE算法对混合特征进行降维,将降维后的特征集作为MSVM分类器的输入进行训练,同时采用粒子群算法对MSVM分类器进行参数寻优。最后用训练好的模型对动态数据流进行异常模式的识别。并将所提方法与单一类型特征方法、混合特征方法的识别模型进行比较,仿真结果和应用实例表明,所提方法的识别精度较高,可用于生产过程的质量异常模式识别中。     

振动给料随流孕育装置压簧减振支撑组件设计

设计一种以压簧为弹性元件的减振支撑组件,不仅可以方便地调试确定振动给料随流孕育装置中的电磁振动给料系统所需的最佳减振效果,而且可以使其支撑组件免受其外界环境温差变化的影响,且结构简单,经久耐用,可靠性强,具有可推广的价值。     

Structure and weights optimisation of a modified Elman network emotion classifier using hybrid computational intelligence algorithms: a comparative study

Artificial neural networks are efficient models in pattern recognition applications, but their performance is dependent on employing suitable structure and connection weights. This study used a hybrid method for obtaining the optimal weight set and architecture of a recurrent neural emotion classifier based on gravitational search algorithm (GSA) and its binary version (BGSA), respectively. By considering the features of speech signal that were related to prosody, voice quality, and spectrum, a rich feature set was constructed. To select more efficient features, a fast feature selection method was employed. The performance of the proposed hybrid GSA-BGSA method was compared with similar hybrid methods based on particle swarm optimisation (PSO) algorithm and its binary version, PSO and discrete firefly algorithm, and hybrid of error back-propagation and genetic algorithm that were used for optimisation. Experimental tests on Berlin emotional database demonstrated the superior performance of the proposed method using a lighter network structure.     

硅对铸态厚壁高韧性球铁QT400—18影响的研究

本文通过研究硅对高炉冷却壁用铸态球铁的力学性能和导热性能的影响，确定了硅含量的最佳范围；讨论了硅对硅对孕育效果及碎块块状石墨形成的影响。生产实践表明，采用本研究设计的低硅随流孕育方案，成功地生产出铸态厚高性球铁冷却壁。     

基于小波变换的金属断口模式识别与分类

提出了一种基于小波变换的金属断口模式识别分类方法。该方法采用Daubechies四点小波和标准的金字塔结构小波变换对粘口图像进行二级小波变换，将小波变换后各个频带输出的L1范数、能量、熵作为断口分类的特征，并根据特征本身的离散程度对特征进行加权处理，采用线性最小距离分类器，对等轴塑坑、腐蚀疲劳、河流花样、拉长塑抗、韧性疲劳和韧性沿晶等六种典型的断口进行分类。实验结果表明，这种方法可以对金属断口模式进行准确的识别与分类。     

柱坐标流函数解析半无限体压入

对平冲头压入半无限体问题建立了柱坐标流函数速度场，证明了该速度场散度为零，旋度为剪切应变速度的２倍。采用上界定理对该速度场积分，变形力与滑移线法结果相一致，证明了流线为一族同心圆（曲线族滑移线），柱坐标流函数的解法比直角坐标的简化。     

Direct numerical simulation of melt–gas hydrodynamic interactions during the early stage of atomisation of liquid intermetallic

The dynamic interactions between Raney Ni–Al intermetallic melt and argon gas at the start of atomisation, near the nozzle of close-coupled gas atomiser, for the first time, are numerically investigated using a front-tracking formulation. Some key geometric parameters of a real device are used in the model in order to simulate the real atomiser. In the model predictions of gas/melt movement, the gas jets cause melt stream pinch off and force the melt stream to wet the melt nozzle tip. Meanwhile, the melt flow has a strong influence on the evolution of gas recirculation via significant feedback. The simulated evolution of the melt stream topology up to disconnection is positively supported by related experimental results. The mechanism of the stagnation point formation proves to be very different from that predicted in conventional gas-only case studies. The peak pressure along the vertical centre line significantly varies once the melt stream becomes disconnected. The pressure gradient within the melt stream in the vertical direction contributes to the aspiration pressure, which is over-ambient with the specific parameters of this paper. This is the first time that direct numerical simulation has been used to investigate the melt–gas two-fluid flow in a real gas atomiser. Besides delivering a deep insight into the physical process involved, this new model has the potential to supply industrially applicable predictions.     

Performance of candidate gas turbine abradeable seal materials in high temperature combustion atmospheres

The development of abradeable gas turbine seals for higher temperature duties has been the target of an EU‐funded R&D project, ADSEALS, with the aim of moving towards seals that can withstand surface temperatures as high as ～ 1100°C for periods of at least 24,000 h. The ADSEALS project has investigated the manufacturing and performance of a number of alternative materials for the traditional honeycomb seal design and novel alternative designs. This paper reports results from two series of exposure tests carried out to evaluate the oxidation performance of the seal structures in combustion gases and under thermal cycling conditions. These investigations formed one part of the evaluation of seal materials that has been carried out within the ADSEALS project. The first series of three tests, carried out for screening purposes, exposed candidate abradeable seal materials to a simulated natural gas combustion environment at temperatures within the range 1050–1150°C in controlled atmosphere furnaces for periods of up to ～ 2,500 h with fifteen thermal cycles. The samples were thermally cycled to room temperature on a weekly basis to enable the progress of the degradation to be monitored by mass change and visual observation, as well as allowing samples to be exchanged at planned intervals. The honeycombs were manufactured from PM2000 and Haynes 214. The backing plates for the seal constructions were manufactured from Haynes 214. Some seals contained fillers or had been surface treated (e.g. aluminised). The second series of three tests were carried out in a natural gas fired ribbon furnace facility that allowed up to sixty samples of candidate seal structures (including honeycombs, hollow sphere structures and porous ceramics manufactured from an extended range of materials including Aluchrom YHf, PM2Hf, Haynes 230, IN738LC and MarM247) to be exposed simultaneously to a stream of hot combustion gas. In this case the samples were cooled on their rear faces to produce a temperature gradient through the seals and the samples were thermally cycled by switching the natural gas off every three hours. The total exposure period for each test was ～ 1,000 h, with seal face temperatures of 1000–1180°C. The performance of the materials in these tests was evaluated using visual observations and cross‐sectional examinations using optical and SEM/EDX techniques. The data gathered have included measurements of oxide thickness and metal‐loss on the exposed samples. A wide range of materials performances has been observed in these studies from minimal damage through to total destruction of samples. Overall, this study has shown that there is still a lot of development work required in order to move to higher temperature sealing systems structures in gas turbine applications.     

随流孕育对WD615飞轮金相组织和断面敏感性的影响

利用金相显微镜、布氏硬度计分析了随流孕育处理对WD615飞轮金相组织和断面敏感性的影响。结果表明,飞轮采用0．10％的Si-Zr随流孕育处理,能够消除D型石墨和碳化物,获得均匀分布的A型片状石墨,并改善了其断面敏感性。用Si-Zr孕育剂进行随流孕育处理在WD615飞轮生产中取得了良好的效果。     

价值流在液压螺纹插装阀精益制造的应用

为改进某液压公司螺纹插装阀生产过程,对生产线进行精益改善。以价值流图为主线,运用山积图识别和记录过程中的浪费,采用5 Whys法分析产生浪费的原因。利用ECRS方法优化生产线结构和工艺以消除浪费,并结合标准作业方法绘制价值流未来状态图,实现了对生产线的精益改善。结果表明:改善后比改善前生产周期缩短了34.9%,在制品库存天数缩短了56.8%,增值比提升了51.2%,生产效率明显提升。     

自动变速器供油调压系统减压回路的稳定性分析

以自动变速器供油调压系统中由定值输出减压阀组成的减压回路为研究对象,建立其由初始状态至建立起稳定压力全过程的数学模型,并利用Matlab/Smulink软件进行仿真,分析减压阀阻尼孔、敏感腔容积、二次回路腔室容积以及阀芯所受库仑摩擦力等因素对二次压力稳定性的影响,为自动变速器供油调压系统中减压回路的参数优化设计打下基础。     

基于LabVIEW的图像识别系统在油泵焊接生产线中的应用

随着计算机等相关技术的发展,图像处理技术越来越多地应用于焊接工业生产质量监控中。利用基于LabVIEW技术的图像处理软件IMAQVision,对被测工件图像进行图像增强、模版匹配、二值化处理、形态学处理等一系列图像处理及图像识别,从而设计出可以在线检测柴油机油泵锁紧垫片安装质量的目标图像识别系统。实验结果表明,设计的系统完成了预定目标,有较好的实际应用价值。     

MAG焊旋转喷射过渡熔滴运动形态的相关分析

熔滴旋转喷射过渡ＭＡＧ焊是用于钢结构的一种高效焊接方法,在窄间隙焊和角焊缝时还可以克服焊接时侧壁的熔剑不良等缺陷。本文用高速摄影方法拍摄了Ａｒ＋Ｏ２保护气体时旋转喷射过渡的熔滴过渡形态,建立了液尖－液流束运动的相关分析模型,并由此分析讨论了熔滴运动的动态变化过程和旋转参数。结果表明,用本文提出的“相关分析”方法,可以确定液尖与液流束运动的主从关系。在脉冲旋转喷射过渡期间,液尖、液流束均绕焊丝轴线做     

高强度灰铸铁缸体铁液处理工艺研究

介绍了6DL、道依茨(Deutz)、6DM、6DN系列灰铸铁缸体铸件的力学性能要求。对材料性能不稳定的原因进行了分析,提出了稳定材料性能的试验研究内容,最后采取了以下改进措施:采用预处理剂,提高铁液形核、抗衰退、受孕育能力;选用优质增C剂,增加石墨核心数量;改变铁液充型的进液位置;适当降低原铁液w(C)、w(Si)及w(Mn)量,提高w(S)量;降低GF300合金加入量,并将GF300合金改成随流变质处理剂,与随流孕育剂一同在浇注时加入到铁液中。结果显示:上述各系列缸体的本体抗拉强度已稳步提高,达到了技术要求。     

基手LabVIEW的图像识别系统在油泵焊接生产线中的应用

随着计算机等相关技术的发展，图像处理技术越来越多地应用于焊接工业生产质量监控中。利用基于LabVIEW技术的图像处理软件IMAQVision，对被测工件图像进行图像增强、模版匹配、二值化处理、形态学处理等一系列图像处理及图像识别，从而设计出可以在线检测柴油机油泵锁紧垫片安装质量的目标图像识别系统。实验结果表明，设计的系统完成了预定目标，有较好的实际应用价值。     

激光同轴送粉增材制造粉末束流关键特征表征与分析

粉末束流焦距和焦点位置处的粉末颗粒的空间分布是粉末束流的两个关键特征,对激光同轴送粉增材制造工艺特性影响较大. 利用高速摄像拍摄粉末束流的宏观形貌,以图像灰度处理技术为基础,建立了粉末束流焦距和焦点位置处粉末颗粒空间浓度分布表征方法,提出利用有效粉斑直径定量分析粉末束流的汇聚性,系统研究了载气流量、同轴保护气流量、送粉速率等主要工艺参数对粉末束流关键特征的影响规律. 结果表明,工艺参数的改变几乎不影响粉末束流焦点位置处粉末颗粒呈高斯分布这一规律;载气流量增加,粉末束流焦距变小,有效粉斑直径变大,粉末束流汇聚性变差;同轴保护气流量增加,粉末束流焦距变长,有效粉斑直径基本不变;送粉速率提高,粉末束流的焦距和有效粉斑直径变化均不大.     

A new triangle element for the axisymmetric UBET

UBET is a useful technique for the analysis of forging and other metal forming processes. However, geometrical shape of a element used in this technique is limited to a rectangle or a right angle triangle. To overcome this problem, an arbitrary shape triangle element which define a kinematically admissible velocity field using stream function is proposed and applied to the UBET. Although, this triangle element is a proper element to be used for the analysis of plane strain problem, it has several problems to be applied to axisymmetric problem. Therefore, a new arbitrary shape triangle element which has constant inlet flow at the side of the triangle is developed. On this element, a kinematically admissible velocity field is expressed easily using stream function and a second order isoparametric triangle element. The power consumption is calculated by the numerical integration. Also, a new conversion technique is introduced for the minimization of power consumption, and it makes possible to use many variables on UBET.     

消失模冷粘结模具的三维造型与设计

运用现代辅助设计方法－三维造型，完成了复杂箱体消失模冷粘结模的设计。结果表明，采用参数的三维造型方法使模具设计柔性强，周期短，并为后续的模具制造提供了可靠的数据流。