Analyzing open-source software systems as complex networks

Software systems represent one of the most complex man-made artifacts. Understanding the structure of software systems can provide useful insights into software engineering efforts and can potentially help the development of complex system models applicable to other domains. In this paper, we analyze one of the most popular open-source Linux meta packages/distributions called the Gentoo Linux. In our analysis, we model software packages as nodes and dependencies among them as edges. Our empirical results show that the resulting Gentoo network cannot be easily explained by existing complex network models. This in turn motivates our research in developing two new network growth models in which a new node is connected to an old node with the probability that depends not only on the degree but also on the “age” of the old node. Through computational and empirical studies, we demonstrate that our models have better explanatory power than the existing ones. In an effort to further explore the properties of these new models, we also present some related analytical results.     

A modular attachment mechanism for software network evolution

A modular attachment mechanism of software network evolution is presented in this paper. Compared with the previous models, our treatment of object-oriented software system as a network of modularity is inherently more realistic. To acquire incoming and outgoing links in directed networks when new nodes attach to the existing network, a new definition of asymmetric probabilities is given. Based on this, modular attachment instead of single node attachment in the previous models is then adopted. The proposed mechanism is demonstrated to be able to generate networks with features of power-law, small-world, and modularity, which represents more realistic properties of actual software networks. This work therefore contributes to a more accurate understanding of the evolutionary mechanism of software systems. What is more, explorations of the effects of various software development principles on the structure of software systems have been carried out, which are expected to be beneficial to the software engineering practices.     

基于LabVIEW的水质监测中心软件设计

针对目前我国的水质污染情况严重,水质监测手段相对落后的现状,设计了基于LabVIEW的多功能水质监测上位机软件。系统采用网络通信方式,从物联网云平台上获取数据,并结合MATLAB、Access数据库和Elman神经网络技术,分别设计出了系统概述模块、数据接收模块、水质报警模块、数据存储模块、记录查询模块和数据预测模块,完成了数据接收、存储、查询、预测等功能。测试结果表明,该系统稳定可靠,各功能模块均能正常运行,达到了软件设计标准,实现了预期的功能。     

大规模软件系统的无标度特性与演化模型

在软件工程中，常用类图来描述类之间的关系. 以软件系统网为研究对象，通过对Sun和IBM公司提供的大规模软件系统进行实证分析，发现Java软件系统网的度分布是无标度分布，标度指数γ≈2.5. 在软件系统网的演化过程中，除加点之外，还存在边的添加、边的随机移除与边的重连等局部事件. 由此建立了软件系统演化模型. 由该模型演化生成的网络，其度分布服从幂律分布. 实际应用与数值仿真验证了该模型的有效性. 关键词： 软件系统 复杂网络 度分布 无标度     

The eight-fold way for optical quasicrystals

Network theory is increasingly employed to study the structure and behaviour of social, physical and technological systems — including civil infrastructure. Many of these systems are interconnected and the interdependencies between them allow disruptive events to propagate across networks, enabling damage to spread far beyond the immediate footprint of disturbance. In this research we experiment with a model to characterise the configuration of interdependencies in terms of direction, redundancy, and extent, and we analyse the performance of interdependent systems with a wide range of possible coupling modes. We demonstrate that networks with directed dependencies are less robust than those with undirected dependencies, and that the degree of redundancy in inter-network dependencies can have a differential effect on robustness depending on the directionality of the dependencies. As interdependencies between many real-world systems exhibit these characteristics, it is likely that many such systems operate near their critical thresholds. The vulnerability of an interdependent network is shown to be reducible in a cost effective way, either by optimising inter-network connections, or by hardening high degree nodes. The results improve understanding of the influence of interdependencies on system performance and provide insight into how to mitigate associated risks.     

Communities and dynamical processes in a complex software network

Complex technological networks represent a growing challenge to support and maintain as their number of elements become higher and their interdependencies more involved. On the other hand, for networks that grow in a decentralized manner, it is possible to observe certain patterns in their overall structure that may be taken into account for a more tractable analysis. An example of such a pattern is the spontaneous formation of communities or modules. An important question regarding the detection of communities is if these are really representative of any internal network feature. In this work, we explore the community structure of a real complex software network, and correlate this modularity information with the internal dynamical processes that the network is designed to support. Our results show that the dependence between community structure and internal dynamical processes is remarkable, supporting the fact that a community division of this complex network is helpful in the assessment of the underlying dynamical structure, and thus is a useful tool to achieve a simpler representation of the complexity of the network.     

OCAD与其他光学设计程序及应用软件的链接和互动

介绍了OCAD(optical CAD)光学设计软件包与国内外其他著名光学设计软件，如美国ORA公司的CodeV，Focus Software公司的Zemax，还有OSLO、LENSVIEW、ASAP和TRACEPRO等，以及国内SOD 88等的链接及互动方法。指出OCAD光学设计软件包本身不仅具有光学设计软件最基本的功能，而且可以利用自身功能界面随时调用上述软件程序为其所用，做到各程序间有效链接，行为互动;OCAD光学设计软件包还可以和文字处理及工作报表等通用程序，如Word和Excel等程序进行链接和互动。针对我国光学设计和光学制图的国家标准，部颁标准及企业标准推出了面向国内的OCAD光学设计软件包。提出目前国内外有关光学设计软件的功能及特点已非常丰富，没必要重复研制内容相同的新软件，只有针对自身的特殊需要研制一些专用应用软件即可。     

Validation and accuracy of software for peak synthesis in XPS

The development of a range of VAMAS format data files containing synthetic test spectra and their use in evaluating the peak fitting routines of three commercial XPS data analysis systems A, B and C, is reported. The synthetic spectra allow tests for: (1) acceptance of VAMAS formats with kinetic energy or binding energy scales that may have positive or negative abscissa increments; (2) Gaussian–Lorentzian sum or product function peaks; (3) effectiveness of Shirley background subtraction; (4) effectiveness of Tougaard background subtraction; (5) peak synthesis with partly resolved peaks with no background; and (6) peak synthesis with a Shirley background. The results show that all the data systems studied accept VAMAS format files but not all would accept both of the options of direction of scan. In addition, each data system had programming faults, some of which were later rectified.Synthetic spectra approximating the carbon 1s peaks for poly(methyl methacrylate), poly(vinyl acetate), poly(vinyl chloride) and poly(isobutylene) allow an analysis of accuracy of the fits in these tests. One full set of spectra is constructed with Gauss–Lorentz product function peaks and a second full set with Gauss–Lorentz sum function peaks since each software was designed for fitting only one of these options. The fitting of the individual peaks is only good for software using the same peak shapes as those of the data. The fit quality can deteriorate markedly for fitting to a peak shape different to that used in the peak fitting algorithm (ie fitting sum function peaks with product function software or vice versa). For unresolved peaks additional information is required to provide meaningful intensities. The three software systems studied all have different facilities but it is clear that the quality of convergence to the correct result gives a general order of preference in the fitting algorithm of B, A and C. Other aspects can favour software A which has more facilities.     

基于模型的软件接口故障注入测试平台技术

针对软件接口类型多、接口故障注入自动控制复杂的困难以及目前缺少有效的软件接口故障注入工具现状,对软件故障注入中的交联接口故障注入技术展开研究,提出了一种基于模型的软件接口故障注入测试平台技术。通过交联接口测试可视化建模和接口故障注入算子设计,自动生成XML 格式的测试用例,并且通过基于XSLT的脚本自动化生成与执行技术实现测试的控制与执行。故障注入测试主机与接口故障注入器网络连接,接口故障注入器将接口故障数据转换成以太网、串口或CAN网络数据注入到被测软件中,并返回被测件输出数据到测试主机实现测试数据收集与判断。基于模型的软件接口故障注入测试平台具有较强的通用性与易用性,提高了接口故障注入测试的效率,降低了接口测试的成本。     

Multifractal analysis of the tensile fracture morphology of polyvinylidene chloride/glass fiber composite

In the present work, the building panel of glass fiber reinforced polyvinylidene chloride composite was prepared and the tensile fracture surfaces of the composites were investigated by the box-counting method of multifractal theory. It suggested that the tensile fracture surface of polyvinylidene chloride/glass fiber (PVDC/GF) composite exhibits multifractal features and the tensile fracture surface morphology of the composite have a strong dependence on the mechanical properties. The results showed that the variation of glass fiber content would lead to the change of mechanical properties, which were responsible for the tensile fracture morphology of PVDC/GF composite. Consequently, the gray value distribution characterizing the surface morphology on the tensile fracture surface would become more non-uniform or less due to this change. The multifractal spectrum could correspondingly mirror this variation according to multifractal methodology. It indicated that the width in multifractal spectrum is sensitive to the morphology of the tensile fractured surface. It is concluded that the multifractal spectrum is the result of the change in mechanical properties of the composites. Additionally, it also suggested that the tensile fracture of the composite is the result of the competition between ductile fracture and brittle fracture by comparing the multifractal spectra and the multifractal spectra would correspondingly change due to this competition. The more the percentage of ductile fracture is, the more rough the fracture surface, the larger the width in the multifractal spectrum. Therefore, it is thought that the multifractal spectrum could feature the rough morphology of the tensile fractured surface and the mechanical properties quantitatively.     

The role of neural architecture and the speed of signal propagation in the process of synchronization of bursting neurons

Synchronized neuronal activity has been observed at all levels of human and any other nervous systems and was suggested as particularly relevant in information processing and coding. In the present paper we investigate the synchronization of bursting neuronal activity. Motivated by the fact that in neural systems the interplay between the network structure and the dynamics taking place on it is closely interrelated, we develop a spatial network representation of neural architecture in which we can tune the network organization between a scale-free network with dominating long-range connections and a homogeneous network with mostly adjacent neurons connected. Our results reveal that the most synchronized response is obtained for the intermediate regime where long- as well as short-range connections constitute the neural architecture. Moreover, the optimal response is additionally enhanced when the speed of signal propagation is optimized.     

Asymmetric Fractal Characteristics and Market Efficiency Analysis of Style Stock Indices

As a typical complex system, the stock market has attracted the attention of scholars and investors to comprehensively understand its fractal characteristics and analyze its market efficiency. Firstly, this paper proposes an asymmetric, detrended fluctuation analysis based on overlapping sliding windows (OSW-A-MFDFA). It reduces the generation of fluctuation errors, and the calculation results are more robust and reliable. The advantage of the OSW-A-MFDFA is that it not only can reveal the multifractal characteristics of time series clearly, but also can further accurately analyze the asymmetry of fractal characteristics under different trends. Secondly, this paper focuses on the variation in the width difference and height difference of the multifractal spectrum under different trends. Finally, based on multifractality, this paper proposes a comprehensive indicator MED that can be used to measure market efficiency, which is characterized by traversing all fluctuation orders. The application revealed many interesting findings in style stock indices. Style stock indices have asymmetric multifractal characteristics, and there are significant differences in the fractal spectrum of different style assets. Moreover, the market efficiency of style stock indices is time-varying, which can be reasonably explained from the perspective of the adaptive market hypothesis.     

Neuronal integration of dynamic sources: Bayesian learning and Bayesian inference

One of the brain's most basic functions is integrating sensory data from diverse sources. This ability causes us to question whether the neural system is computationally capable of intelligently integrating data, not only when sources have known, fixed relative dependencies but also when it must determine such relative weightings based on dynamic conditions, and then use these learned weightings to accurately infer information about the world. We suggest that the brain is, in fact, fully capable of computing this parallel task in a single network and describe a neural inspired circuit with this property. Our implementation suggests the possibility that evidence learning requires a more complex organization of the network than was previously assumed, where neurons have different specialties, whose emergence brings the desired adaptivity seen in human online inference.     

Self-affine and ARX-models zonation of well logging data

Zonation of time series into models which their parameters are piecewise constant are important and well-studied problems. Geophysical well logging data often show a complex pattern due to their multifractal nature. In a multifractal system, any pieces of it are established by a distinct exponent that can characterize them. This feature has the capability to cluster them. Self-affine zonation by Auto Regressive model with exogenous inputs (ARX) is a new approach which places well logging segments in the clusters which are more self-affine against the other clusters. This approach was performed and compared with a conventional ARX zonation in the well logging data of three different oilfields in southern parts of Iran. The results showed a good accuracy for detecting homogeneous lithological segments and led to a precise interpretation process to update the reservoir architecture.     

Deterministic non-periodic structures

Summary Aperiodic structures which are perfectly ordered, but lack translational symmetry, can be considered as intermediate between crystalline and amorphous systems. Their wave-functions and spectra exhibit unusual properties. A one-dimensional model, known as the Thue-Morse lattice, is here investigated; it is particularly interesting because it is deterministic non-periodic, but not quasi-periodic. The propagation of both electrons and photons is considered and the corresponding spectra are characterized with a multifractal analysis. The multifractal scaling function τ(q) tends in both cases to a non-analytic limit that implies the presence of both extended and exponentially localized states, as confirmed by the behaviour of the wave functions. In honour of Prof. Fausto Fumi on the occasion of his retirement from teaching.     

基于激光散斑成像的零件表面粗糙度建模

表面粗糙度是衡量机械表面加工水平的重要参数. 通过构建一套激光散斑成像采集系统, 获取了不同表面加工类型和不同粗糙度值的零件表面激光散斑图像. 应用Tamura纹理特征理论提取图像的纹理粗糙度、对比度、方向度特征, 并分析了这三个特征与表面粗糙度的关系. 发现了纹理粗糙度特征与表面粗糙度的单调关系, 推导出平磨、外磨、研磨三种表面加工工艺的粗糙度值与图像纹理粗糙度特征的数学函数关系, 实现了表面粗糙度的测量. 同时, 利用Tamura纹理特征与加工工艺的依赖关系, 建立了基于贝叶斯网络的工艺识别推理模型, 推理出了零件表面加工工艺. 通过为多种加工类型表面建立粗糙度测量模型, 为粗糙度测量提供了新思路. 实验证明所提的粗糙度测量模型能以较高的准确率识别出零件表面加工类型并测量出其表面粗糙度值.     

脑电信号的标度分析及其在睡眠状态区分中的应用

脑电信号具有长程幂律相关性及多重分形的标度特性,并随生理病理状态改变.本文首次针对睡眠脑电信号应用单重分形去趋势波动分析(detrended fluctuation analysis,简记为DFA)方法与多重分形奇异谱对睡眠脑电信号的标度特征进行系统的对比研究.发现DFA标度指数α对于不同导联和样本组间的差异较为敏感,随睡眠状态的变化不规律;而多重分形奇异强度区间Δα随睡眠状态的变化更为规律,睡眠Ⅰ期至Ⅳ期不断增大,并且导联间差异和样本组间差异均较小.多重分形Δα参数更适合作为判定睡眠状态的定量参数.     

Multifractal analysis and randomness of almost periodic forced two-level systems

Numerical results of multifractal analysis of the (quantum) dynamics of forced two-level systems under some almost periodic time dependence are reported. The aims are to check the presence of multifractal characteristics of these systems, and also to inspect if different degrees of aperiodicities in the force are transferred to the system dynamics. Although the dynamics present signatures of the randomness of the perturbation, it does not follow strictly its autocorrelation type. The wavelet transform is the tool used to carry out the multifractal analysis.     

DEIReconstructor:a software for diffraction enhanced imaging processing and tomography reconstruction

Diffraction enhanced imaging (DEI) has been widely applied in many fields, especially when imaging low-Z samples or when the difference in the attenuation coefficient between different regions in the sample is too small to be detected. Recent developments of this technique have presented a need for a new software package for data analysis. Here, the Diffraction Enhanced Image Reconstructor (DEIReconstructor), developed in Matlab, is presented. DEIReconstructor has a user-friendly graphical user interface and runs under any of the 32-bit or 64-bit Microsoft Windows operating systems including XP and Win7. Many of its features are integrated to support imaging preprocessing, extract absorption, refractive and scattering information of diffraction enhanced imaging and allow for parallel-beam tomography reconstruction for DEI-CT. Furthermore, many other useful functions are also implemented in order to simplify the data analysis and the presentation of results. The compiled software package is freely available.