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大规模软件系统的无标度特性与演化模型   总被引:9,自引:0,他引:9       下载免费PDF全文
闫栋  祁国宁 《物理学报》2006,55(8):3799-3804
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  相似文献   
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闫栋  董明  Abdelaziz Bouras  于随然 《中国物理 B》2011,20(4):40205-040205
In a scale-free network,only a minority of nodes are connected very often,while the majority of nodes are connected rarely. However,what is the ratio of minority nodes to majority nodes resulting from the Matthew effect In this paper,based on a simple preferential random model,the poor-rich demarcation points are found to vary in a limited range,and form a poor-rich demarcation interval that approximates to k/m ∈ [3,4]. As a result,the (cumulative) degree distribution of a scale-free network can be divided into three intervals: the poor interval,the demarcation interval and the rich interval. The inequality of the degree distribution in each interval is measured. Finally,the Matthew effect is applied to the ABC analysis of project management.  相似文献   
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闫栋  祁国宁  顾新建 《中国物理》2006,15(11):2489-2495
In software engineering, class diagrams are often used to describe the system's class structures in Unified Modelling Language (UML). A class diagram, as a graph, is a collection of static declarative model elements, such as classes, interfaces, and the relationships of their connections with each other. In this paper, class graphs are examined within several Java software systems provided by Sun and IBM, and some new features are found. For a large-scale Java software system, its in-degree distribution tends to an exponential distribution, while its out-degree and degree distributions reveal the power-law behaviour. And then a directed preferential-random model is established to describe the corresponding degree distribution features and evolve large-scale Java software systems.  相似文献   
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金属薄壁结构由于其优异的轻质性和耐撞性,一直被广泛地应用在汽车、飞机和火车等交通工具的碰撞动能耗散系统中。以一种类向日葵薄壁夹芯吸能结构为研究对象,研究了在瓣尖压和瓣间压两种径向冲击载荷下,类向日葵薄壁夹芯结构的变形模式、能量吸收能力、比吸能和平均压缩力。结果表明,类向日葵薄壁夹芯结构的壁厚、花瓣数、加载速度以及加载方向都会对结构的耐撞性产生一定的影响。在质量恒定条件下,随着外壳厚度的增加,瓣尖压冲击方式下薄壁结构的吸能效率降低,瓣间压比瓣尖压的比吸能最高多出了44.6%。随着花瓣数的变化,金属薄壁结构的吸能效率存在一个最优值。  相似文献   
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