一种UML2的交互的形式化语义

UML2(unified modeling language2.x)的规范为其交互定义了一种基于事件发生轨迹的语义,弥补了之前版本在语义上的欠缺。但是此语义是用自然语言(英语)描述的,不够精确、不一致,并且很多细节解释得不够清楚和完备。利用集合论以组合定义的方式形式化语义,并且证明了形式化后交互的语义为拟序集,此拟序集的线性化恰好就是规范所定义的轨迹集。此形式化语义可以作为UML2交互规范的很好的补充,不但有助于UML2交互的理解,还为UML2交互的应用和研究奠定了坚实的理论基础。     

Semantics and Verification of Data Flow in UML 2.0 Activities

One of the major changes in going from UML 1.5 to UML 2.0 is the reengineering of activity diagrams. This paper examines activity diagramies as described in the current version of the UML 2.0 standard by defining a denotational semantics. It covers basic control flow and data flow, but excludes hierarchy, expansion nodes, and exception handling (see [Störrle, H., Semantics of Control-Flow in UML 2.0 Activities, in: P. Bottoni, C. Hundhausen, S. Levialdi and G. Tortora, editors, Proc. IEEE Symposium on Visual Languages and Human-Centric Computing (VL/HCC) (2004), pp. 235–242, Störrle, H., Semantics of Exceptions in UML 2.0 Activities (2004), submitted to Journal of Software and Systems Modeling, May, 9^th, available at www.pst.informatik.uni-muenchen.de/~stoerrle, Störrle, H., Semantics of Expansion Nodes in UML 2.0 Activities, in: I. Porres, editor, Proc. 2^nd Nordic Ws. on UML, Modeling, Methods and Tools (NWUML'04), 2004] for these issues). The paper shows, where the constructs proposed in the standard are not so easily formalized, and how the formalisation may be used for formal analysis.     

UML活动图的形式语义及分析

UML活动图缺乏精确的动态语义,不利于对其所描述的系统进行形式化的分析、验证和确认。为此,论文结合Petri网给出了包含对象流状态描述的UML活动图的形式语义,并据此对UML活动图的典型流程和其所描述的动态系统的正确性进行了分析。该形式语义覆盖了UML活动图的绝大部分特征,为精确描述工作流程并对其进行分析奠定了基础。     

UML在数据库建模中的应用

UML是目前面向对象分析设计中的一种标准建模技术,它被用作确定、构建和文档化一个系统的结构.本文主要探讨以UML对象类图为中心出发点,来为数据库建模的方法:在UML的对象类中得到关系模式的键;把关联的多重性分配到关系模式中去;把泛化(继承)联系转换为关系模式;把行为(操作)转换为触发器和存储过程.     

On Capturing Semantics in Ontology Mapping

Semantic interoperability between disparate systems in open, distributed environments has become the quest of many practitioners in a variety of fields. One way to achieve such a goal is through ontology mapping. The perspective users of such technology, however, are faced with a number of challenges including ambiguity of the meaning of mappings, difficulties of capturing semantics, choice of the right ontology mapping tools, verification and validation of results and operationalisation in the beneficiary semantic web application. In this paper we present a formalisation of ontologies and a triangle model for the ontology mapping problems. This formalisation of ontology mapping reflects the engineering steps needed to materialise a versatile mapping system in order to faithfully re-capture the semantics embodied in ontologies which is the fundamental requirements posed by the semantic web environment. We further accommodate this formalisation with a series of specialist algorithms targeting at particular aspects of semantic capturing. Finally, we evaluated the proposed algorithms by way of ontology mapping benchmark tests.     

UML建模过程探讨

对UML作了简要介绍,描述了建模过程研究与运用领域的现状。根据UML的语言特点提出了一种简洁、实用的建模过程。     

On the Computation of the Disjunctive Well-Founded Semantics

A characterization of the disjunctive well-founded semantics (DWFS) is given in terms of the Gelfond–Lifschitz transformation. This characterization is used to develop a top-down method of testing DWFS membership, employing a hyperresolution-like operator and quasi-cyclic trees to handle minimal model processing. A flexible bottom-up method of computing the DWFS is also given that admits the use of a powerful reduction operator. For finite propositional databases, all of our methods run in polynomial space.     

MDA中关联从UML模型到Java模型的转换

关联变换是MDA中模型转换的难点,研究了如何定义一套高质量的映射规则用于关联变换.首先讨论了UML中关联关系及其两种实现模式,接着对每种模式分别定义了一套从UML模型（平台独立模型）到Java模型（平台相关模型）的变换规则,最后给出了两种实现模式按规则转换的实例.     

On the Dynamic Semantics and the Timing Behavior of Ravenscar Kernels

Mature research advances in scheduling theory show that carefully-crafted concurrent computational models permit static analysis of real-time behavior. This evidence enables designers to consider using suitable forms of explicit concurrency to model the inherent concurrency of real-time systems. The Ravenscar Profile, a specifically tailored subset of the Ada 95 tasking model, defines a compact and efficient concurrent computational model, especially suited for the development of high integrity, high efficiency real-time systems.Ravenscar runtimes can be implemented by small, efficient, reliable and certifiable kernels. At least two such implementations already exist and are being industrially deployed. The simplicity and intrinsic determinism of Ravenscar kernels facilitate the definition of metrics that cater for very accurate characterization of the dynamic behavior of the runtime and of the execution time of its primitives. Accurate runtime metrics enable forms of response time analysis that minimize the pessimism in the prediction of the runtime influence on the application. This is especially useful for concurrent systems that exhibit significant dependency on runtime support services. This paper recalls the motivations of the Ravenscar Profile, outlines the definition of it and formulates a precise characterisation of the associated runtime metrics.     

基于关联规则的移动通信业务间关联的分析

利用数据挖掘中的关联规则发现技术设计并实现了一个移动业务关联规则发现系统,通过对实验结果进行分析,系统能够根据用户的参数设置自动发现移动通信业务之间的相关性和规律,并界面友好地显示给用户。帮助移动通信行业的决策者发现当前各业务之间的联系,从而有针对性地实施点对点营销,达到增收的目的。     

关于BAN逻辑的语义模型的分析与改进

该文针对BAN逻辑及其语义模型的不足之处,提出了改进后的定义,它比BAN原作者们所提供的信念定义更加合理。     

Semantics and the crowd

One of the principal scientific challenges that drives my group is to understand the character of formal knowledge on the Web. By formal knowledge     

On the Semantics of Deliberation in IndiGolog — from Theory to Implementation

We develop an account of the kind of deliberation that an agent that is doing planning or executing high-level programs under incomplete information must be able to perform. The deliberator's job is to produce a kind of plan that does not itself require deliberation to interpret. We characterize these as epistemically feasible programs: programs for which the executing agent, at every stage of execution, by virtue of what it knew initially and the subsequent readings of its sensors, always knows what step to take next towards the goal of completing the entire program. We formalize this notion and characterize deliberation in the situation calculus based IndiGolog agent programming language in terms of it. We also show that for certain classes of problems, which correspond to those with bounded solutions and those with solutions without sensing, the search for epistemically feasible programs can be limited to programs of a simple syntactic form. Finally, we discuss implementation issues and execution monitoring and replanning too.     

基于UML的研究生培养系统建模的研究

为了实现学位申请人基本数据远程提交,院系、研究生部答辩资格审查网络化,以提高工作效率,采用统一建模语言UML建立模型,描述了从功能分析、系统设计,到物理模型设计的整个过程,将复杂的研究生培养系统用简单明了的可视化图形表示出来,给整个系统的开发提供了有利的条件,具有现实意义。     

On evaluating the layout of UML diagrams for program comprehension

UML class and sequence diagrams are helpful for understanding the static structure and dynamic behavior of a software system. Algorithms and tools have been developed to generate these UML diagrams automatically for program understanding purposes. Many tools, however, often ignore perceptual factors in the layout of these diagrams. Therefore, users still have to spend much time and effort rearranging boxes and lines to make the diagram understandable. This article presents key criteria and guidelines for the effective layout of UML class and sequence diagrams from the perspective of perceptual theories. Two UML tools are evaluated to illustrate how the criteria can be applied to assess the readability of their generated diagrams. Kenny Wong is an Associate Professor in the Department of Computing Science at the University of Alberta. His main areas of research include software comprehension, evolution, and visualization. This research includes building, using, and evaluating integrated environments for reverse engineering, and devising strategies to understand and evolve diverse software systems. He is General Chair of the 2007 International Conference on Program Comprehension in Banff, and Program Chair of the 2008 International Conference on Software Maintenance in Beijing. Dabo Sun is an M.Sc. student in the Department of Computing Science at the University of Alberta. His research interests include program comprehension, software visualization, and end-user software engineering. He has assisted the teaching of courses in software engineering and web information systems. He also has been working as a software engineer on developing and maintaining industrial software systems.     

On the impact of size to the understanding of UML diagrams

Background

Practical experience suggests that usage and understanding of UML diagrams is greatly affected by the quality of their layout. While existing research failed to provide conclusive and comprehensive evidence in support of this hypothesis, our own previous work provided substantial evidence to this effect, also suggesting diagram size as a relevant factor, for a range of diagram types and layouts.

Aims

Since there is no generally accepted precise notion of “diagram size,” we first need to operationalize this concept, analyze its impact on diagram understanding, and derive practical advice from our findings.

Method

We define three alternative, plausible metrics. Since they are all highly correlated on a large sample of UML diagrams, we opt for the simplest one. We use it to re-analyze existing experimental data on diagram understanding.

Results

We find a strong negative correlation between diagram size and modeler performance. Our results are statistically highly significant and exhibit a very large degree of validity. We utilize these results to derive a recommendation on diagram sizes that are, on average, optimal for model understanding. These recommendations are implemented in a plug-in to a widely used modeling tool, providing continuous feedback about diagram size to modelers.

Conclusions

The effect sizes are varying, but generally suggest that the impact of size matches or exceeds that of other factors in diagram understanding. With the guideline and tool, modelers are steered toward avoiding too large diagrams.