A generic simulation model for evaluating concurrency control protocols in native XML database systems

In this paper we propose a generic simulation model, named XSM, with which researchers can construct standard platforms and evaluate their proposed concurrency control protocols for native XDBMSs. The system environment, the performance metrics, and the protocol rules of various types of XML protocols are all considered by the model. To facilitate the implementation of XSM, the state diagrams, the sequence diagrams, the component diagram, and the class diagram of XSM are depicted using UML 2.0 notations. We also show a simulation platform constructed from XSM to fairly and comprehensively evaluate the performance of various XML protocols.     

Generalized Block Diagrams

The conventions and rules for generalized block diagram representation are developed and the relationships between generalized block diagrams and network graphs discussed. The generalized block diagram as developed here should prove of value in the computer-aided study of complex systems.     

Investigating Reasoning with Constraint Diagrams

Constraint diagrams are a visual notation designed to express logical constraints. Augmenting the diagrams with a reading tree (effectively a partial ordering of quantifiers) ensures that each diagram has a unique semantic interpretation.In this paper, we discuss examples of reasoning rules for augmented constraint diagrams which exhibit interesting properties or difficulties that can arise when developing rules for such a diagrammatic system. We do not present a complete set of rules, but investigate the generic problems arising, providing solutions. One problem corresponds to the nesting of quantifiers and another relates to the domain of universal quantification. These issues may be an important consideration in the definition of other logical reasoning systems which explicitly represent quantification diagrammatically.     

基于UML和Petri网的锅炉仿真系统的研究

结合了UML状态图的表达特性和Petri网的分析特性,总结出状态图的设计步骤和状态图转化为Petri网的规则,并以国家质检总局科技项目-锅炉仿真系统为背景,对锅炉自动燃烧过程实例进行分析,按照设计步骤和转化规则,最终用Petri网描述出实例,为进一步分析系统特性奠定基础.     

Logichart — Intelligible Program Diagram for Prolog and its Processing System

An intelligible program diagram called Logichart has been developed for Prolog visualization. Its syntax rules and layout rules are formalized in terms of an attribute graph grammar. This grammar is underlain by a context–free graph grammar whose productions are defined to formalize the graph–syntax rules of Logichart diagrams. Semantic rules attached to the productions are defined in such a way that they can extract the layout information needed to display a Logichart diagram as attributes. Our Prolog visualization system, which has been implemented based on the attribute graph grammar, can draw a Logichart diagram for any correct Prolog program (completeness), and any Logichart diagram displayed by the system is always valid for the grammar (soundness). The system can also display the execution of a Prolog program in real time; that is, the Logichart diagram is dynamically updated as the program runs.     

具有不稳定零极点对消的结构图等效问题

为进一步完善经典控制论中的结构图简化规则,深入研究具有不稳定零极点对消的结构图等效问题。指出复杂结构图等效后,如果其等效式与其他环节存在不稳定零极点对消,则对消后系统的性质将发生改变,此时应保持原结构图而不做进一步的简化,仿真示例验证这一结论。     

计算机绘制三元系等活度图方法的研究

以三元系等活度线计算机绘制过程中出现的锯齿形问题,抓住常见等活度线的一般规律,提出一种新的三元系等活度线的计算方法。通过转换浓度变量,构造一组在计算范围内单调的方程,确保了绘图不出现锯齿形。此法原理简单,可用于各种热力学模型的等活度线计算。用于SReM热力学模型,并建立等活度图绘制程序。程序具有界面友好、应用灵活、实用性强的特点。用之于绘图,表明本文提出的方法,可有效避免出现锯齿形。     

Topological semantics for lumped parameter systems modeling

Behaviors of many engineering systems are described by lumped parameter models that encapsulate the spatially distributed nature of the system into networks of lumped elements; the dynamics of such a network is governed by a system of ordinary differential and algebraic equations. Languages and simulation tools for modeling such systems differ in syntax, informal semantics, and in the methods by which such systems of equations are generated and simulated, leading to numerous interoperability challenges. Logical extensions of SysML aim specifically at unifying a subset of the underlying concepts in such languages.We propose to unify semantics of all such systems using standard notions from algebraic topology. In particular, Tonti diagrams classify all physical theories in terms of physical laws (topological and constitutive) defined over a pair of dual cochain complexes and may be used to describe different types of lumped parameter systems. We show that all possible methods for generating the corresponding state equations within each physical domain correspond to paths over Tonti diagrams. We further propose a generalization of Tonti diagram that captures the behavior and supports canonical generation of state equations for multi-domain lumped parameter systems.The unified semantics provides a basis for greater interoperability in systems modeling, supporting automated translation, integration, reuse, and numerical simulation of models created in different authoring systems and applications. Notably, the proposed algebraic topological semantics is also compatible with spatially and temporally distributed models that are at the core of modern CAD and CAE systems.     

Contract-collaboration network method for modeling manufacturing resource control workflows

This paper presents contract-collaboration network (CC-Net) method that is developed to model manufacturing resource control workflows. The CC-Net is an object-oriented class diagram. It depicts the contract-collaboration relationships among the classes in a manufacturing system, with constraints. The CC-Net method uses a primitive modeling block called collaboration module by which the CC-Net is established systematically. This idea is very similar to that of the Lego® block toy. Unlike most workflow modeling methods, the CC-Net method views workflow modeling as a constraint satisfaction process. That is, describing the set of constraint recovery rules corresponding to the constraint violations is regarded as workflow modeling. The obtained set of workflow rules is free from process deadlock and considers all the events of triggering the workflow. We explore the use of the CC-Net method for the workflow modeling of a flexible manufacturing system.     

More Fun with Symmetric Venn Diagrams

Many researchers have had fun searching for and rendering symmetric Venn diagrams, culminating in the recent result of Griggs, Killian, and Savage ("Venn Diagrams and Symmetric Chain Decompositions in the Boolean Lattice," Electronic Journal of Combinatorics, 11 (2004), R2), that symmetric Venn diagrams on n curves exist if and only if n is prime. Our purpose here is to point out ways to prolong the fun by introducing and finding the basic properties of Venn and near-Venn diagrams that satisfy relaxed notions of symmetry, while leaving tantalizing open problems. A symmetric Venn diagram is one that possesses a rotational symmetry in the plane. A monochrome symmetric Venn diagram is one that is rotationally symmetric when the colours of the curves are ignored. A necessary condition for the existence of a monochrome symmetric Venn diagram is that the number of curves be a prime power. We specify conditions under which all curves must be non-congruent and give examples of small visually striking monochrome symmetric Venn diagrams found by algorithmic searches. A Venn diagram partitions the plane into 2ⁿ open regions. For non-prime n we also consider symmetric diagrams where the number of regions is as close to 2ⁿ as possible, both larger and smaller.     

Towards an Integrated Graph Based Semantics for UML

Recently, we proposed an integrated formal semantics based on graph transformation for central aspects of UML class, object and state diagrams. In this paper, we explain the basic ideas of that approach and show how two more UML diagram types, sequence and collaboration diagrams, can be captured. For UML models consisting of a class diagram and particular state diagrams, a graph transformation system can be defined. Its graphs are associated with system states and its rules with operations in the class diagram and transitions in the state diagrams. Sequence and collaboration diagrams then characterize sequences of operation applications and therefore sequences of transformation rule applications. Thus valid sequence and collaboration diagrams correspond to derivations induced by the graph transformation system. Proceeding this way, it can be checked for example whether such an operation application sequence may be applied in a specific system state.     

Refactoring OCL annotated UML class diagrams

Refactoring of UML class diagrams is an emerging research topic and heavily inspired by refactoring of program code written in object-oriented implementation languages. Current class diagram refactoring techniques concentrate on the diagrammatic part but neglect OCL constraints that might become syntactically incorrect by changing the underlying class diagram. This paper formalizes the most important refactoring rules for class diagrams and classifies them with respect to their impact on attached OCL constraints. For refactoring rules that have an impact on OCL constraints, we formalize the necessary changes of the attached constraints. Our refactoring rules are specified in a graph-grammar inspired formalism. They have been implemented as QVT transformation rules. We finally discuss for our refactoring rules the problem of syntax preservation and show, by using the KeY-system, how this can be resolved.     

State diagrams and steady-state balance equations for open queuing network models

In this paper, the state diagrams and steady-state balance equations for two kinds of open queuing network models are presented. The first model comprises a network of single queues with single servers, while the second model comprises multiple servers for single queues. State diagrams are drawn for (2, 3) queuing networks with (i) single servers and (ii) multiple servers. Steady-state balance equations are derived from the state diagrams. The paper provides a method to solve open queuing networks by analyzing the stochastic process involved in the transition of states in a continuous time Markov chain which represents the state diagram of a queuing system.     

Exact Computation of the Topology and Geometric Invariants of the Voronoi Diagram of Spheres in 3D

In this paper, we are addressing the exact computation of the Delaunay graph (or quasi-triangulation) and the Voronoi diagram of spheres using Wu’s algorithm. Our main contributions are first a methodology for automated derivation of invariants of the Delaunay empty circumsphere predicate for spheres and the Voronoi vertex of four spheres, then the application of this methodology to get all geometrical invariants that intervene in this problem and the exact computation of the Delaunay graph and the Voronoi diagram of spheres. To the best of our knowledge, there does not exist a comprehensive treatment of the exact computation with geometrical invariants of the Delaunay graph and the Voronoi diagram of spheres. Starting from the system of equations defining the zero-dimensional algebraic set of the problem, we are applying Wu’s algorithm to transform the initial system into an equivalent Wu characteristic (triangular) set. In the corresponding system of algebraic equations, in each polynomial (except the first one), the variable with higher order from the preceding polynomial has been eliminated (by pseudo-remainder computations) and the last polynomial we obtain is a polynomial of a single variable. By regrouping all the formal coefficients for each monomial in each polynomial, we get polynomials that are invariants for the given problem. We rewrite the original system by replacing the invariant polynomials by new formal coefficients. We repeat the process until all the algebraic relationships (syzygies) between the invariants have been found by applying Wu’s algorithm on the invariants. Finally, we present an incremental algorithm for the construction of Voronoi diagrams and Delaunay graphs of spheres in 3D and its application to Geodesy.     

Contour diagram fuzzy model for maximum surface ozone prediction

A contour diagram approach is presented for the identification of surface ozone concentration feature based on a set of rules by considering the meteorological variables such as the solar radiation, wind speed, temperature, humidity and rainfall. A fuzzy rule system approach is used because of the imprecise, insufficient, ambiguous and uncertain data available. The contour diagrams help to identify qualitative ozone concentration variability rules which are more general than conventional statistical or time series analysis. In the methodology, ozone concentration contours are based on a fixed variable as ozone precursor, namely, NO_x and as the third variable one of the meteorological factors. Such contour diagrams for ozone concentration variation are prepared for six months. It is possible to identify the maximum ozone concentration episodes from these diagrams and then to set up the valid rules in the form of IF-THEN logical statements. These rules are obtained from available daily ozone, NO_x and meteorological data as a first approximate reasoning step. In this manner, without mathematical formulations, expert maximum ozone concentration systems are identified. The application of the contour diagram approach is performed for daily ozone concentration measurements on European side of Istanbul city. It is concluded that through approximate reasoning with fuzzy rules, the maximum ozone concentration episodes can be identified and predicted without any mathematical expression.     

CDADE: Conflict detector in activity diagram evolution based on speech act and ontology

Software system user requirements tend to change and evolve over time. The UML activity diagrams are a useful language for modeling system processes. Additionally, designers must often maintain activity diagrams incrementally. This paper presents the CDADE tool, which can help designers detect conflicts in activity diagram evolution. The CDADE tool is composed of ontologies, metadata, and conflict detection rules. Speech act theory is used to reveal evolutionary change in the activity diagrams. The CDADE prototype and a case study of electronic commerce are presented to demonstrate and validate the feasibility and effectiveness of the CDADE tool.     

顺序图与状态图的递归语义一致性研究

建模面向对象的软件系统是UML的动态图的重要应用,采用顺序图描述消息传送,动态图描述活动.在大型系统开发过程中,往往存在大量顺序图和状态图,由于语义的缺失,导致这些图形表达涵义模糊不清,特别是在递归的信息传送上,由于表达方式的特点,状态图很容易造成实现过程的歧义甚至死锁.提出了基于ASM的多agent实时控制方法,结合形式化的规则定义,通过多个层次agent控制状态的跃迁,保证状态图在描述复杂信息传送时,能够和顺序图的时序保持一致,这对提高系统的可靠性具有一定的现实意义.     

基于UML的医院信息系统建模

UML是一种面向对象的建模语言,能够将用户的业务需求映射为模型,可大大提高系统的开发效率和扩展性。运用UML用例图、时序图、协作图、状态图、活动图等表示方法,对医院信息系统HIS的需求和业务流程进行分析与设计,准确地表达系统的功能需求,有效解决了HIS的需求分析和业务建模问题,为下一步的总体设计奠定了良好的基础。     

一种SysML模型到AADL模型的自动转换方法

安全关键系统的实现需要通过需求、设计、集成、验证和测试等多个阶段。近年来,模型驱动开发方法逐渐成为安全关键系统设计与开发的重要手段。由于还没有一个建模语言能够支持整个安全关键系统开发生命周期,因此选择集成使用2种广泛使用的标准语言:系统建模语言(SysML)和嵌入式实时系统体系结构分析与设计语言(AADL)。SysML和AADL提供了同一系统的2个不同视图,SysML模型为系统工程师提供了一个系统视图,AADL为架构设计师建立一个较低层次的设计视图,它结合了实现所有功能的硬件、操作系统和代码。提出一种SysML模型到AADL模型的自动转换方法。首先,定义SysML子集SubSysML,主要包括模块定义图(BDD)、内部模块图(IBD)、活动图(ACT)子集和从IBD和BDD扩展的AADL Profile;其次,定义SubSysML到AADL的转换规则并设计转换算法;然后,对生成的AADL初始模型进行精化;最后,使用EMF框架技术实现SubSysML到AADL的模型转换工具并通过雷达案例验证所提方法的有效性。