边际函数的绝对连续性

本文给出边际函数的绝对连续性性质．     

一般化的灰SOM模型及其性能评估

自组织特征映射是Kohonen提出的一种人工神经网络模型，它能把高维的信息数据以有序方式映射到低维空间上，形成一种拓扑意义上的有序图，但其权值的调整仅考虑了学习率及输入模式与获胜神经元及其邻域，却忽略了输入模式分量与全体参与竞争的神经元权值向量间的某种相关关系。Hu等人利用灰关系系数(GRC)的描述方法显式地刻画这种关系。尽管如此，但GRC仍忽略了输入模式与所有参与竞争的神经元权值间的整体描述关系。该文通过在GRC中引入该整体关系，提出了一个一般化的灰关系模型G^2SOM，并将GSOM作为其特例，进而侧重就三种特殊的函数关系进行了性能评估，最后，通过实验验证了G^2SOM的有效性与可行性。     

地形图点状虚线的自动矢量化研究与实现

虚线的矢量化一直是地形图自动识别的难点之一。文章通过人眼对虚线视觉感知特性的分析，提出了基于点与点之间相互作用的视觉组织模型。根据感知的类似性对地图图像进行形态滤波，然后运用有界深度优先搜索法生成初始种子段，提出可变形模型迭代算法实现对虚线的自动跟踪矢量化。从理论分析及实验结果得出，本算法是行之有效的，具有稳定性好、易于实现的特点。     

Evaluation of Linguistic Features for Word Sense Disambiguation with Self-Organized Document Maps

Word sense disambiguation automatically determines the appropriate senses of a word in context. We have previously shown that self-organized document maps have properties similar to a large-scale semantic structure that is useful for word sense disambiguation. This work evaluates the impact of different linguistic features on self-organized document maps for word sense disambiguation. The features evaluated are various qualitative features, e.g. part-of-speech and syntactic labels, and quantitative features, e.g. cut-off levels for word frequency. It is shown that linguistic features help make contextual information explicit. If the training corpus is large even contextually weak features, such as base forms, will act in concert to produce sense distinctions in a statistically significant way. However, the most important features are syntactic dependency relations and base forms annotated with part of speech or syntactic labels. We achieve 62.9% ± 0.73% correct results on the fine grained lexical task of the English SENSEVAL-2 data. On the 96.7% of the test cases which need no back-off to the most frequent sense we achieve 65.7% correct results.     

Geometrical study of the three-dimensional temperature–composition diagrams. An important aid to understand the behavior of the liquid–vapour equilibrium in ternary systems

In this work the usefulness of qualitatively studying and drawing three-dimensional temperature–composition diagrams for ternary systems is pointed out to understand and interpret the particular behavior of the liquid–vapour equilibrium of non-ideal ternary systems. Several examples have been used in order to highlight the interest and the possibilities of this tool, which should be an interesting support not only for lecturers, but also for researchers interested in experimental equilibrium data determination.     

Roman glazed inkwells from the “Nuovo Mercato di Testaccio” (Rome,Italy): Production technology

This study is focused on Roman lead-glazed inkwells from the archaeological site of the “Nuovo Mercato di Testaccio” (Rome, Italy) dated in the half 2nd century AD. Optical microscopy (OM), X-ray powder diffraction (XRPD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and electron microprobe analysis (EMPA) have been used. Petrographic analysis of the body indicated the occurrence of only one fabric. The reaction zone at the contact glaze/body is marked by the enucleating of euhedral Pb-bearing alkali feldspar from a felsic melt enriched in Pb as revealed by EMP analysis. The mineralogical assemblages of the body and glaze, the microstructure and the chemical composition suggest that the inkwells were fired in the range 950–1100 °C, under oxidizing conditions.     

Vibrations of an aramid anchor cable subjected to turbulent wind

The vibration response of an initially pre-stressed anchor cable made of parallel-lay aramid fibres excited by a measured and artificially simulated spatial turbulent wind field is presented in the paper. Results of the analyses of in situ measured wind records are described. For selected data set statistical characteristics and power spectral density functions of the measured wind velocity components are calculated. The wind stochastic velocity fluctuation is modelled as a one-variate bi-dimensional random field. Cross-power spectral density functions, at different point locations are introduced. The combination of the weighted amplitude wave superposition method (WAWS) with the Shinozuka–Deodatis method is used for the analyzed problem. A time-dependent behaviour of the synthetic cable is investigated which is subjected to turbulent wind with large expected oscillations that arise as a result of slackening due to the relaxation effects. A nonlinear transient dynamic analysis is used in conjunction with the finite element method to determine the dynamic response of the cable subjected to turbulent wind at its initially prestressed state and in the selected times after the relaxation effect. The constitutive equation of the relaxation of the aramid cable follows an experimentally obtained law of the logarithmic type. To monitor the dependences of the individual quantities of cable vibration in the phase space, attractors and Poincaré maps are created by sampling the cable’s displacement and velocity at periods of relevant frequencies. Interesting findings based on the response of the cable with rheological properties to turbulent wind are presented.     

Exploratory analysis of excitation-emission matrix fluorescence spectra with self-organizing maps—A tutorial

Large datasets are common in chemical and environmental engineering applications and tools for their analysis are in great demand. Here, the outputs of a series of fluorescence spectroscopy analyses are utilised to demonstrate the application of the self-organising map (SOM) technique for data analysis. Fluorescence spectroscopy is a well-established technique of organic matter fingerprinting in water. The technique can provide detailed information on the physico-chemical properties of water. However, analysis of fluorescence spectra requires the application of robust statistical and computational data pre-processing and analysis tools.This paper presents a tutorial for training engineering postgraduate researchers in the use of SOM techniques using MATLAB^®. Via a tutorial, the application of SOM to fluorescence spectra and, in particular, the characterisation of organic matter removal in water treatment, is presented. The tutorial presents a step-by-step example of the application of SOM to fluorescence data analysis and includes the source code for MATLAB^®, together with presentation and discussion of the results. With this tutorial we hope to popularise this robust pattern recognition technique for fluorescence data analysis and large data sets in general, and also to provide educational practitioners with a novel tool with which to train engineering students in SOM.     

Tribo-oxidation maps for Ti against steel

A fundamental study of wear transition regimes was carried out for a pin-on-disk sliding couple, involving titanium and steel. The sliding speed was varied from 0.38 to 1.5 m s⁻¹ and the normal load from 10 to 50 N. Wear mapping approaches have been undertaken to represent the transitions in wear modes and wear mechanisms regimes, as a function of applied normal loads and sliding speeds and for both pin and disc separately on the basis of experimental results. Dry sliding wear behaviour of steel was characterized by tribo-oxidative wear with high material transfer from the titanium. In contrast, adhesive wear was more prevalent for the titanium and oxidative wear mechanisms led to formation of non-protective films on the surface.     

Mental maps compared to actual spatial behavior using GPS data: A new method for investigating segregation in cities

This article examines the relationship between perceived territorial boundaries and actual spatial activity. The methodology used includes a combination of mental maps and interviews for examining perceptions of territorial boundaries, with tracking technology (GPS) and activity diaries to track the actual use of space. This methodology was implemented in a pilot study with a sample of 18 women living in Jerusalem, including secular Jews, ultra-orthodox Jews, and Palestinian Muslims.The study found a very strong relationship between perceived personal territory and actual spatial activity. However, while the secular Jewish women appeared to be completely segregated within their territory, the ultra-orthodox Jewish women and the Palestinian Muslim women were both very active within the secular Jewish territory, but avoided each other’s territories. The analysis of mental maps and actual spatial patterns of residential daily activities challenges prevailing notions about the spatial structure of Jerusalem and the internal power relations between the populations that inhabit it. More generally, it provides a new methodological approach for investigating segregation in cities.