武汉城市圈中小企业融资发展与风险控制研究

作为国民经济重要力量的中小企业,面临融资发展困境是世界各国共性问题。武汉城市圈中小企业融资难问题的解决,可以借鉴美国、日本的经验做法。研究表明,政策性金融设立、融资渠道创新以及风险控制机制的营建是突破中小企业融资瓶颈的有效路径。     

基于AutoCAD的二维渐开线齿轮造型方法研究

齿轮是机械传动中不可或缺的零件,目前大部分的齿轮都采用渐开线齿廓。对如何绘制齿轮轮廓线、进而生成齿轮三维图形一直都是工程人员比较棘手的问题。文中基于AutoCAD软件平台,根据渐开线齿廓的形成特点及参数方程,详细介绍了二维渐开线齿轮的造型方法以及如何得到足够精确的渐开线齿轮轮廓,为后续设计奠定了基础。     

A NEW DIGITAL MODULATION RECOGNITION METHOD USING FEATURES EXTRACTED FROM GAR MODEL PARAMETERS

Based on the features extracted from generalized autoregressive (GAR) model parameters of the received waveform, and the use of multilayer perceptron(MLP) neural network classifier, a new digital modulation recognition method is proposed in this paper. Because of the better noise suppression ability of the GAR model and the powerful pattern classification capacity of the MLP neural network classifier, the new method can significantly improve the recognition performance in lower SNR with better robustness. To assess the performance of the new method, computer simulations are also performed.     

Forgetting Exceptions is Harmful in Language Learning

We show that in language learning, contrary to received wisdom, keeping exceptional training instances in memory can be beneficial for generalization accuracy. We investigate this phenomenon empirically on a selection of benchmark natural language processing tasks: grapheme-to-phoneme conversion, part-of-speech tagging, prepositional-phrase attachment, and base noun phrase chunking. In a first series of experiments we combine memory-based learning with training set editing techniques, in which instances are edited based on their typicality and class prediction strength. Results show that editing exceptional instances (with low typicality or low class prediction strength) tends to harm generalization accuracy. In a second series of experiments we compare memory-based learning and decision-tree learning methods on the same selection of tasks, and find that decision-tree learning often performs worse than memory-based learning. Moreover, the decrease in performance can be linked to the degree of abstraction from exceptions (i.e., pruning or eagerness). We provide explanations for both results in terms of the properties of the natural language processing tasks and the learning algorithms.     

旋流器分级磨矿回路测控系统

本文介绍了旋流器分级磨矿回路测控系统的原理配置及特点 ,结合实际应用 ,论述了该测控系统的功能及使用结果     

Age estimation using a hierarchical classifier based on global and local facial features

The research related to age estimation using face images has become increasingly important, due to the fact it has a variety of potentially useful applications. An age estimation system is generally composed of aging feature extraction and feature classification; both of which are important in order to improve the performance. For the aging feature extraction, the hybrid features, which are a combination of global and local features, have received a great deal of attention, because this method can compensate for defects found in individual global and local features. As for feature classification, the hierarchical classifier, which is composed of an age group classification (e.g. the class of less than 20 years old, the class of 20-39 years old, etc.) and a detailed age estimation (e.g. 17, 23 years old, etc.), provide a much better performance than other methods. However, both the hybrid features and hierarchical classifier methods have only been studied independently and no research combining them has yet been conducted in the previous works. Consequently, we propose a new age estimation method using a hierarchical classifier method based on both global and local facial features. Our research is novel in the following three ways, compared to the previous works. Firstly, age estimation accuracy is greatly improved through a combination of the proposed hybrid features and the hierarchical classifier. Secondly, new local feature extraction methods are proposed in order to improve the performance of the hybrid features. The wrinkle feature is extracted using a set of region specific Gabor filters, each of which is designed based on the regional direction of the wrinkles, and the skin feature is extracted using a local binary pattern (LBP), capable of extracting the detailed textures of skin. Thirdly, the improved hierarchical classifier is based on a support vector machine (SVM) and a support vector regression (SVR). To reduce the error propagation of the hierarchical classifier, each age group classifier is designed so that the age range to be estimated is overlapped by consideration of false acceptance error (FAE) and false rejection error (FRE) of each classifier. The experimental results showed that the performance of the proposed method was superior to that of the previous methods when using the BERC, PAL and FG-Net aging databases.     

涡流分级机的分级轮研究

在分级系统中,分级轮对于物料的分散、分级起着非常重要的作用。通过分析气体在分级轮中所受的作用力,推导出分级粒径公式,并得出分级轮的风量、转速与分级粒度及分级精度的关系。     

Parametric Analysis of the Stability of Degraded Railroad Platforms

The current study is developed based on one of the types of subgrade rupture risk suggested by Selig and Waters （1994）. It aims to evaluate subgrade stability railroad, which consists of the slope stability analysis of a railway yard embankment subjected to a wagon load type gondola parked on this track. This proposed analysis was taken into consideration because there are Brazilian railroads in high deterioration level. In some of these lines the tracks are submitted to increasing amount of load every year. The adopted model slope stability to the studied railroad embankments considers the rupture on circular line. It was applied the Geoslope-Slope/W software, version 6, to the evaluation of the platform-slope system. Several situations are adopted to reach the minimum safety slope, permitting to analyze the platform stability to keep railroad traffic under adequate safety level.     

展成磨齿机磨削不同压力角渐开线圆柱齿轮的方法

展成磨齿机的砂轮磨削角为αs,当被磨削渐开线圆柱齿轮分度圆法向压力角αn不同于砂轮磨削角αs时,通过参数换算得出αjn=αs时的磨削节圆直径dj和磨削节圆螺旋角βj,使操作复杂的展成磨齿机可以磨削不同法向模数mn、不同分度圆法向压力角αn及不同齿数z等各类渐开线圆柱齿轮,减少更换修整磨削砂轮时间及工件的中间检测调整次数,提高展成磨齿机的综合效率。     

煤与瓦斯共采钻孔增透半径理论分析与应用

在煤与瓦斯共采时,受采动加、卸载应力影响,瓦斯抽采钻孔围岩塑性区内煤体会产生大量裂隙,增大了瓦斯的渗透率,形成瓦斯增透圈,增透圈半径的大小直接影响瓦斯的抽采效果。以钻孔围岩"蝶形塑性区"理论为基础,建立了钻孔塑性区与瓦斯增透圈模型,首次推导出了钻孔增透圈半径解析式。深入分析了钻孔增透半径影响因素发现:增透半径与钻孔半径成线性正比例关系,与最小围压和围压比值呈类指数增长关系,与岩石黏聚力和内摩擦角呈负指数变化关系;其中最小围压与围压比值是影响增透半径的关键因素,深部开采与高围压比值是形成大尺寸有效增透圈的必要和充分条件。这一理论为煤与瓦斯共采中瓦斯抽采钻孔间距设计、位置选择、方向确定、采场与钻孔布置在时间和空间上关系协调提供了科学依据。