虚拟环境中装配设计语义的表达、传递与转化研究

研究了虚拟环境产品装配建模过程中装配语义的表达、装配语义与装配约束的转化技术,提出了采用语义－约束图对装配设计语义与约束进行维护。通过语义－约束图可以从语义层次和约束层次对产品装配模型进行编辑和维护。提出了采用模糊参量表达和处理产品装配设计中的模糊语义。基于模糊参量的语义表达不仅为设计信息输入提供了更大的自由度,而且扩展了计算机对模糊信息的处理能力,有利于产品设计意图的维护。通过产品装配信息从抽象到具体、从模糊到精确的转化,实现了虚拟装配设计系统对抽象、模糊设计信息的表达、传递与处理。     

A geometric modelling framework for conceptual structural design from early digital architectural models

Computer support for conceptual structural design is still ineffective. This is due, in part, to the fact that current computer applications do not recognize that structural design and architectural design are highly interdependent processes, particularly at the early stages. The goal of this research is to assist structural engineers at the conceptual stage with early digital architectural models. This paper presents a geometric modeling framework for facilitating the engineers’ interactions with architectural models in order to detect potential structural problems, uncover opportunities, respect constraints, and ultimately synthesize structural solutions interactively with architectural models. It consists of a process model, a representation model and synthesis algorithms to assist the engineer on demand at different stages of the design process. The process model follows a top-down approach for design refinements. The representation model describes the structural system as a hierarchy of entities with architectural counterparts. The algorithms rely on geometric and topologic relationships between entities in the architectural model and a partial structural model to help advance the synthesis process. A prototype system called StAr (Structure-Architecture) implements this framework. A case study illustrates how the framework can be used to support the conceptual structural design process.     

Information schema constructs for instantiation and composition of system manifestation features

Complementing our previous publications, this paper presents the information schema constructs (ISCs) that underpin the programming of specific system manifestation feature (SMF) orientated information management and composing system models. First, we briefly present (1) the general process of pre-embodiment design with SMFs, (2) the procedures of creating genotypes and phenotypes of SMFs, (3) the specific procedure of instantiation of phenotypes of SMFs, and (4) the procedure of system model management and processing. Then, the chunks of information needed for instantiation of phenotypes of SMFs are discussed, and the ISCs designed for instantiation presented. Afterwards, the information management aspects of system modeling are addressed. Methodologically, system modeling involves (1) placement of phenotypes of SMF in the modeling space, (2) combining them towards the desired architecture and operation, (3) assigning values to the parameters and checking the satisfaction of constraints, and (4) storing the system model in the SMFs-based warehouse database. The final objective of the reported research is to develop an SMFs-based toolbox to support modeling of cyber-physical systems (CPSs).     

CHARMY: A Framework for Designing and Verifying Architectural Specifications

Introduced in the early stages of software development, the Charmy framework assists the software architect in making and evaluating architectural choices. Rarely, the software architecture of a system can be established once and forever. Most likely poorly defined and understood architectural constraints and requirements force the software architect to accept ambiguities and move forward to the construction of a suboptimal software architecture. Charmy aims to provide an easy and practical tool for supporting the iterative modeling and evaluation of software architectures. From an UML-based architectural design, an executable prototype is automatically created. Charmy simulation and model checking features help in understanding the functioning of the system and discovering potential inconsistencies of the design. When a satisfactory and stable software architecture is reached, Java code conforming to structural software architecture constraints is automatically generated through suitable transformations. The overall approach is tool supported.     

Product modeling framework based on interaction feature pair

Designing products effectively and efficiently is of great significance. However, currently part models are usually created without knowing how they will interact with other parts, leading to gaps between part modeling and assembly modeling and between other applications, and to tedious and redundant labor. This paper proposes a novel product modeling framework to address the problems. The framework is different from current product modeling systems from two aspects. On the architecture level, a new module based on a concept of interaction feature pair (IFP) is developed. An IFP incorporates information of interaction type, related feature pairs and behavioral information that fulfill the interactions. The new module can model the structure of IFPs mathematically through operators and functions defined in a space spanned from six basic IFPs. It can also utilize the constituent elements of an IFP as state variables to form behavior models for the IFP. On the process level, the IFP-based framework can support both bottom-up and top-down approaches, and integrate part modeling and assembly modeling together by changing the workflows. Concretely, IFPs will be embedded into part models at part modeling stage to make them pre-interact with each other, and at assembly modeling stage, parts will be assembled by instantiating the embedded IFPs instead of specifying mating constraints, thus reducing the tedious and redundant labor. Incorporating knowledge of different domains, IFPs can also be developed to integrate more applications together. The implementation of the framework is demonstrated through a prototype system.     

Multi-level assembly model for top-down design of mechanical products

To enable next generation CAD tools to effectively support top-down design of products, a top-down assembly design process is refined from the traditional product design process to better exhibit the recursive-execution and structure-evolvement characteristics of product design. Based on the top-down assembly design process, a multi-level assembly model is put forward to capture the abstract information, skeleton information and detailed information involved. The multi-level assembly model is a meta-level implementation and is easy to be extended. Moreover, the inheritance mechanisms are explored to ensure the feasibility of information transferring and conversion between different design phases in the top-down assembly design process. A top-down assembly design sample is analyzed at length to show the application effects of the multi-level assembly model and the relevant inheritance mechanisms. In addition, a practical topic about the model adaptation of existing CAD systems is also discussed for a broader application of the top-down assembly design. Finally, the conclusion of the work and the future directions for further exploration are given.     

面向应用的Web服务组合设计和验证框架

针对Web服务组合设计规范缺乏形式化的语义和验证方法的问题,提出了一个自顶向下的Web服务设计和验证的框架-iFrame4WS。在iFrame4WS中,将Web服务组合的设计方案划分为描述层、抽象层和执行层,并通过抽象层的形式化模型和形式化验证来检查Web服务组合的正确性。     

Abstraction database concept for engineering modeling

Engineering modeling and design generally involve a large set of independent but interrelated data items. One way to organize and store these data items in a systematic and consistent manner is through the use of a database management system. The abstraction concepts of aggregation and generalization provide a powerful mechanism for organizing and structuring engineering data. The invariants required to maintain the abstract data model are examined in this paper. Integrity issues involved in the data representation of hierarchically structured engineering models, such as constructive solid geometry models, are discussed. Object-oriented programming concepts are used to implement a prototype integrity subsystem for enforcement of integrity constraints in the aggregation/generalization framework for modeling data.     

一种软件自适应UML建模及其形式化验证方法

软件自适应的建模和形式化验证是提高自适应软件开发效率、保证自适应软件可靠性的基础,现有研究中软件自适应可视化建模与形式化建模相隔离,一定程度上阻碍了自适应软件的开发.为此,提出MV4SAS的方法,将可视化的UML与严格化的时间自动机相结合,用于软件自适应的建模和形式化验证.首先,应用UML扩展机制引入新的构造型、标记值和约束条件,定义软件自适应建模设施,在此基础上构造软件自适应结构模型和行为模型;然后,根据定义好的转换算法将软件自适应行为模型转换为时间自动机网络,建立软件自适应形式化模型;最后,定义一组软件自适应形式化验证性质,并利用模型检测工具UPPAAL验证软件自适应模型的可靠性.案例研究表明,该方法可有效降低软件自适应建模和验证的复杂度,提高软件自适应的建模效率和模型可靠性.     

Structure and spatial consistency of network-based space layouts for building and product design

Network-based space layouts are schematic models of whole spaces, subspaces, and related physical elements. They address diverse space modeling needs in building and product design. A schema (data model) for network-based space layouts is defined that is influenced by existing space schemas. Layout elements and selected spatial relations form a geometric network. The network is embedded in 3-space and facilitates analysis with graph and network algorithms. Spatial constraints on layout elements and spatial relations extend the schema to support spatial consistency checking. Spatially consistent layouts are required for reliable network analysis and desirable for layout modification operations. An operation is introduced that evaluates spatial constraints to detect and semi- or fully-automatically resolve spatial inconsistencies in a layout. A layout modeling system prototype that includes proof-of-concept implementations of the layout schema extended by spatial constraints and the inconsistency resolution operation is described. Layouts of a floor of an office building and a rack server cabinet have been modeled with the system prototype.     

A software engineering perspective on environmental modeling framework design: The Object Modeling System

The environmental modeling community has historically been concerned with the proliferation of models and the effort associated with collective model development tasks (e.g., code generation, data transformation, etc.). Environmental modeling frameworks (EMFs) have been developed to address this problem, but much work remains before EMFs are adopted as mainstream modeling tools. Environmental model development requires both scientific understanding of environmental phenomena and software developer proficiency. EMFs support the modeling process through streamlining model code development, allowing seamless access to data, and supporting data analysis and visualization. EMFs also support aggregation of model components into functional units, component interaction and communication, temporal-spatial stepping, scaling of spatial data, multi-threading/multi-processor support, and cross-language interoperability. Some EMFs additionally focus on high-performance computing and are tailored for particular modeling domains such as ecosystem, socio-economic, or climate change research. The Object Modeling System Version 3 (OMS3) EMF employs new advances in software framework design to better support the environmental model development process. This paper discusses key EMF design goals/constraints and addresses software engineering aspects that have made OMS3 framework development efficacious and its application practical, as demonstrated by leveraging software engineering efforts outside of the modeling community and lessons learned from over a decade of EMF development. Software engineering approaches employed in OMS3 are highlighted including a non-invasive lightweight framework design supporting component-based model development, use of implicit parallelism in system design, use of domain specific language design patterns, and cloud-based support for computational scalability. The key advancements in EMF design presented herein may be applicable and beneficial for other EMF developers seeking to better support environmental model development through improved framework design.     

利用用户定义特征实现基于约束设计

提出了基于约束的用户定义特征（User Defined Feature,UDF)定义与比实例化的通用机制及基于约束的特征库管理,并应用于国产CAD／CAM软件金银花（Lonicera)系统,以航空发动机转子为例,建立了转子特征库,对系统功能进行了验证。该项工作既为详细设计阶段考虑装约束和制造约束提供了方便,提高了设计效率,也为将用户定义特征与产品功能相联系、以支持计算机辅助概念设计打下了基础。     

一种支持多目标框架的模型驱动开发方法

平台无关模型到平台相关模型的转换是OMG提出的模型驱动架构(MDA)中的关键技术。目前多数开发工具将平台相关模型定义为具体的目标运行框架,这严重降低了软件演化过程中设计模型的可重用性。为此,引入抽象平台相关模型和具体平台相关模型的概念,使基于某种平台的业务逻辑设计与目标运行框架相分离,提出一种支持多目标框架代码生成的扩展MDA开发模型。实验证明,该方法提升了模型描述的灵活性和可重用性,能够对模型驱动的软件开发提供有力的支持。     

基于模板的自顶向下并行装配设计

在分析产品设计系统的装配功能的基础上,提出了一个并行装配设计模式及装配模板与模板实例化的概念;在处理装配约束的虚拟表示与实例表示概念,使得系统具有了支持自顶向下和自底向上２种设计方法的能力。该方法已被成功地应用于参数化特征造型系统ＺＤ－ＭＣＡＤＩＩ中,证明了基于装配模板基础上的装配设计方法法能在零件设计级上有效地支持并行设计。     

A constraint-based variability modeling framework

Constraint-based variability modeling is a flexible, declarative approach to managing solution-space variability. Product variants are defined in a top-down manner by successively restricting the admissible combinations of product artifacts until a specific product variant is determined. In this paper, we illustrate the range of constraint-based variability modeling by discussing two of its extreme flavors: constraint-guarded variability modeling and constraint-driven variability modeling. The former applies model checking to establish the global consistency of product variants which are built by manual specification of variations points, whereas the latter uses synthesis technology to fully automatically generate product variants that satisfy all given constraints. Each flavor is illustrated by means of a concrete case study.     

A transformation contract to generate aspects from access control policies

Access control is an important security issue. It has been addressed since the late 1960s in the early time-sharing computer systems. Many access control models have been proposed since than but of particular interest is Ferraiolo and Khun’s role-based access control model (RBAC). It is a simple and yet general model which has been deeply studied and applied both in industry and in academia. A variety of industrial standards have been proposed based on this model. Generating code for an access control policy is an interesting challenge. Understanding access control as a non-functional concern that cross-cuts the functional part of a system raises difficulties quite suitable for a solution based on aspect-oriented programming. In this paper, we address the problems of specification and validation of code generation for access control policies targeting an aspect-based infra-structure. We propose an MDA approach. The code generator is a transformation from SecureUML, an RBAC-based modeling language, to the language Aspects for Access Control (AAC), an aspect-oriented modeling language proposed in this paper. Metamodels are used to represent the languages and to specify the transformation. A metamodel is used to represent the abstract syntax of a language and the constraints that a given instance model of the metamodel must fulfill. We also use a metamodel to specify the code generator. This transformation metamodel, together with all the constraints, that is, from both languages and those constraints regarding the merge of the two languages, we call a transformation contract. It merges and conservatively extends the source and target metamodels of the model transformation it represents. In the context of code-generation for access control policies, the transformation contract specifies the relationships between the abstract syntaxes of SecureUML and AAC and constrains the two languages. The validation of the code generator also uses the transformation contract. For a given access control policy and aspect, represented as instances of the appropriate metamodels, with aspects produced by the code generator, the constraints of the transformation contract must hold. We have prototyped a transformer from SecureUML to aspects on top of ITP/OCL, an OCL interpreter that automatically validates the generated aspect code by applying the constraints of the transformation contract.     

Knowledge-based approach and system for assembly oriented design,Part I: the approach

Assembly is one of the most important stages for product development. Assembly-oriented design (AOD) is a new approach to designing assemblies, which uses a number of design and analysis tools to help the designer plan out and analyze candidate assembly schemes prior to having detailed knowledge of the geometry of the parts. Using this approach, many assembly schemes can be inexpensively evaluated for their ability to deliver the important characteristics of the final product. This research proposes a knowledge-based approach and develops an expert design system to support top-down design for assembled products. The presentation of research report is divided into two parts: the knowledge-based approach (Part I) and the knowledge-based expert design system (Part II). This paper is the first part of the report (Part I), which mainly proposes a knowledge-based approach and framework for intelligent assembly oriented design. The proposed approach focuses on the integration of product design, assemblability analysis and evaluation, and design for assembly with economical analysis. It differs from the existing approaches adopting the part-first bottom-up modeling technique, in which a hybrid model related to design problem-solving including function–behavior–structure model, feature-based geometric model, and parametric constraint model is used as a comprehensive intelligent framework for assembly modeling and design in a top-down manner from the conceptual level to the detailed level. Through the use of intelligent approach and framework, concurrent engineering knowledge can be effectively incorporated into the assembly design process, and a knowledge-based expert design system can be implemented.     

基于CIM的设备状态检修信息模型构建方法

公共信息模型（CIM）描述电力企业中所有主要对象的抽象模型．可以以此为基础采用原型法设计支撑设备状态检修信息化支持平台的信息模型。该方法主要分为需求分析、初步建模、模型验证和迭代优化四个步骤,同时该方法的实施还需要建立一套信息模型应用的长效机制,才能保证设备状态检修信息模型能支撑设备状态检修业务的发展和应用。