Management of complex structural engineering objects in a relational framework

To structure the development of an integrated building design environment, the global representation of the design data may best be organized in terms of hierarchies of objects. In structural engineering design we deal with large sets of independent but interrelated objects. These objects are specified by data. For an engineering design data base the system must be able to model the objects composing the design as well as to manage effectively the design data. The data base management system therefore needs to have some knowledge of the intended use of the data, and must provide an abstraction mechanism to represent and manipulate objects. Much recent research in engineering data bases focuses on object management for specific tasks but gives little attention to the shareability of the underlying information. This paper describes an architecture for the management of complex engineering objects in a sharable, relational framework. Potential application of this approach to object management for structural engineering analysis and design is discussed.     

TOWARD A COMMON STRUCTURAL LEVEL FOR SOFTWARE,DATABASE, AND KNOWLEDGE-BASED SYSTEMS

Abstract

Different languages, tools, and techniques are used for the development of software systems, including database and knowledge-based systems. Although underlying languages employ structuring concepts such as classification, modularization, generalization, and perspectives, these common concepts remain overshadowed by differing terminologies and notations, due to the separate histories of software engineering, databases, and knowledge representation. Currently the still more complex and ambitious requirements on software systems call for integrated solutions concerning software engineering environments. As a starting point toward integration, in this paper we aim at deriving a common structural level for software systems. To approach this goal we start by analyzing the human thought process on one hand and successfully applied structuring techniques on the other hand to derive a catalogue of 10 structuring concepts. Building on that, a self-contained language called SFW (structuring framework) is introduced to provide means for a general and uniform specification of the structure of software systems. SFW is aimed at providing a catalogue of reference for structuring concepts in today's languages as well as a suggestion to establish a uniform structural level in future approaches.     

Autonomous objects: A natural model for complex applications

Object-oriented database systems are emerging as the next generation DBMSs for advanced applications, e.g., VLSI design, mechanical CAD/CAM, software engineering, etc. However, a close analysis indicates that the requirements imposed by these application domains cannot be met by an object-oriented model that relies purely onpassive objects. In this work we go beyond the conventionalsingle-thread-of-control paradigm of passive object models and propose a model ofactive objects which can autonomously initiate responses to environmental changes.Autonomous objects cooperate with each other by synchronous orasynchronous message passing—giving rise to themultiple-thread-of-control in such an environment. It is shown howevents—to which active objects react—can be incorporated into this model. We propose a nondeterministic computational model for the individual active objects that allows the autonomous reaction upon events. We show that this very sparse extension to an object-oriented model gives rise to several high-level features which can be controlled by events. The object-oriented paradigm allows one to isolate the rules according to which events are being raised. This leads to a potentially rather efficient execution model compared to existing relational concepts, which are typically globally-defined event trigger mechanisms.     

An aide for instruction on integrated engineering design and support

Effective management of engineering information is critically needed for the design of future complex engineering systems. Yet engineers are not trained in engineering data base management concepts. To help address this issue, a prototype integrated design system has been developed for the Air Force to aide research and instruction on key integration concepts, including (1) the use of a shared data base to eliminate redundancies and inconsistencies; (2) the use of a relational data base management system to store, locate, and retrieve data from the shared data base; (3) the development of interfacing programs to act as interpreters between the application programs and the common data base; and (4) the role of executive software to manage the integrated system. Key software used includes a computer-aided design system, a structural analysis program, various graphics packages, and a relational data base management system. To assess system flexibility, additional programs were added to the system. The design of the data base proved to be an important step in this implementation. Several methodologies useful in the design of the data base were investigated and subsequently used to organize the data base for the integrated design system. Results discussed include system development, and applications, as well as the effectiveness of the integrated system's configuration.     

A communication model for structural design objects. I: Channels and medium

Design objects of integrated engineering systems frequently communicate data and information among each other. The data to be communicated is usually characterized by considerable variability in format and structure. This warrants the development of a uniform mechanism for communicating data and information among design objects. Recent advances in the object-oriented paradigm and the emerging agent-oriented paradigm gave promise to the development of such mechanism for inter-object communication that was difficult to achieve previously. This paper and its companion paper address this issue and propose an object communication model. Specifically, this paper identifies the communication channels among structural engineering design objects and proposes a communication medium based on messenger object for conveying message arguments and responses. The unified modeling language (UML) is used to present the model and its ingredients. A note on implementation of the messenger object, using C++ STL, is shown. Examples to demonstrate the capability of the communication model are presented. The proposed communication model will impose a uniform and consistent mechanism for communicating data and information among design objects. Other ingredients of the communication model such as performatives and protocols are addressed in the companion paper.     

Supporting engineering applications by new data base processing concepts—An experience report

Data base management systems for nonstandard applications (nonstandard data base systems, NDBS), in particular for engineering applications, nowadays constitute one of the most important challenges in the area of data base research. Some major obstacles are concerned with problems of modeling and processing complex engineering objects. Some new system architectures have been proposed, and appropriate concepts for handling the new types of application objects have been developed over the past few years.Based on PRIMA, an NDBS-kernel prototype implementation, we motivate a workstation-oriented architecture for NDBS application systems. We explain a prototypical application system in the environment of VLSI-chip design, which serves as a practical examples in handling complex objects. Analyzing the weaknesses of this initial approach, we derive general concepts for application linkage, discussing, in particular, key issues for an efficient object processing and language binding.     

Structural modelling of information systems

Information systems have become increasingly complex over recent years, underscoring the challenge of designing systems which will provide the different functions in an organization with the information necessary for effective decision-making. With rapidly developing computer technology, it is natural that information systems evolve in a manner which is greatly dependent on computing hardware and software. Yet, there has been little development in the techniques of systems analysis and design to handle new and less well understood functions which are of increasing interest.

This paper discusses the basic mathematical concepts of structural modelling as related to information system analysis. In particular, its concern is with the structuring of information system networks utilizing these concepts as potentially useful tools in (1) partitioning a system into a set of subsystems; (2) specifying subsystems sufficiently to permit separate testing before total system tests ; and (3) eliminating redundant control information flow.     

A design process model for computer integrated structural engineering

Computer integrated design systems will require an improved understanding of the engineering design process, including formalized notions of (1) the structure of the process, (2) the design tasks that need to be performed, and (3) the information required to carry out these tasks. To help formalize the design process, certain conceptual tools are needed, including an organizational model for the process. This paper outlines such a model for structural engineering design, termed theMultilevel Selection-Development model, which is based on a decomposition of design problems intoselection anddevelopment subproblems. A few basic concepts involved in the engineering design process are reviewed, and the proposed model is outlined. The application of the model to a simple example is presented, and management of the interactions between subproblems is discussed.     

复杂对象版本的数学模型

复合组合对象的版本管理机制是工程数据库系统的重要组成部分。本文以支持工程设计方案的修改，选择及配置为主要目的，对ＣＯＨＯＲ复杂对象进行了版本扩展，提出了复杂对象版本的数学模型，并从语义角度讨论了ＤＡＴＦＥＡ版本管理系统的版本模型和基本操作等问题。     

A neutral object data model for integrated building design and construction environment

Construction and civil engineering projects include large numbers of design elements, materials, activities, in addition to a diversity of data types and complex relationships. The need to adopt appropriate representational schemes and database technologies that can handle complex data types and relationships continue to hinder the search for solutions to an integrated design-construction environment. This paper describes a scheme that classifies and codes design information to support an integrated building design data model. The model is conceptual and based on the object-oriented paradigm. It uses concepts such as objects, attributes and different relations between objects. The main feature of the model is a set of hierarchies of design objects which have classes for describing the various aspects of design elements of a building. These classes represent elements, materials, geometry and construction activities represented by work sections. The model provides classes of data items from which the designer can select to model the various pieces of design elements and their associated work sections. Attributes provide information included in design and construction documents like drawings, specifications and bills of quantities. The model deals with a diversity of data abstracts including multimedia features like sound and video that can be stored in different design documents.     

对象依赖集合性质的研究

在复杂对象模式的规范化设计中,对象间的语义关系起了重要作用。然而,目前还没有关系的研究报告,讨论了对象依赖集合的一些性质,首先概括了基本概念和性质;然后给出并证明获取一个OD集合所有关键字的JINGSI算法;最后证明要作为复杂对象模式规范化设计的MIMI算法输入的OD集合的特性,并基于此改进复杂对象模式规范化设计。     

Object-oriented modeling and simulation of neural networks

The field of neural networks is being investigated by many researchers in order to provide solutions to difficult problems in the area of manufacturing systems. Computer simulation of neural networks is an important part of this investigation. This paper applies concepts from an important trend in software engineering research, namely object-oriented programming, to model neural networks.The design and implementation of a software object library is crucial to obtaining the full benefits of object-oriented programming. In this paper we discuss the design and implementation of a foundation library of software objects for the purpose of simulating and validating different network architectures and learning rules. The library contains objects that implement various types of nodes and learning rules. We discuss the results of our experiments to illustrate the benefits of using an object-oriented approach to modeling neural networks.     

Extending Java to dynamic object behaviors

Class inheritance and dynamic binding are the key features of object-oriented programming and they permit designing and developing complex systems. However, standard class inheritance is essentially static and cannot be directly employed for modeling dynamic object behaviors. In this paper we propose a linguistic extension of Java, called Dec-Java, that is partially inspired by the decorator design pattern. This extension permits easily separating the basic features of objects (that are likely not to change during the application) from their behaviors (that, instead, can be composed dynamically at run-time). Thus, Dec-Java enables a dynamic extension and specialization of object responsibilities.     

基于多进程的测控系统软件设计及其数据通信

文章介绍了基于多进程的测控系统软件设计方法,将复杂测控系统的软件设计分割为若干相互联系的进程设计,并对多进程程序设计中的核心问题即进程间数据通信问题进行了详细的讨论。     

Using an Issue-Based Hypertext System to Capture the Software Life-Cycle Process

Hypertext and object-oriented database technology offer significant possibilities for designing new software engineering environments which better represent the complex relationships between the many artifacts created during the life of a software system. These artifacts are composed of structured (machine understandable) and unstructured information. Hypertext systems can record both the structured and unstructured information of the software project and the linking relationships between both types of information. Issue-based information systems (also called argumentation systems) are special-purpose hypertext systems for capturing the issues and reasoning for decision making. The Issue-Based Experiment (IBE) system is an issue-based information system implemented on an object-oriented database platform. IBE was developed to research methods of capturing the life cycle of a software project in an issue-based information network. IBE is demonstrated to be useful in both the requirements development and system maintenance phases of the software life cycle. Several issues are discussed concerning the usability of issue-based information systems: maintaining a constant level of detail, scoping an Issue for placement in the issue network, and enforcing usage. IBE looks promising when integrated as part of a software development environment based on hypertext and object-oriented database technology.     

A semantic framework and software design to enable the transparent integration,reorganization and discovery of natural systems knowledge

I present a conceptualization that attempts to unify diverse representations of natural knowledge while providing a workable computational framework, based on current semantic web theory, for developing, communicating, and running integrated simulation models. The approach is based on a long-standing principle of scientific investigation: the separation of the ontological character of the object of study from the semantics of the observation context, the latter including location in space and time and other observation-related aspects. I will show how current Knowledge Representation theories coupled with the object-oriented paradigm allow an efficient integration through the abstract model of a domain, which relates to the idea of aspect in software engineering. This conceptualization allows us to factor out two fundamental causes of complexity and awkwardness in the representation of knowledge about natural system: (a) the distinction between data and models, both seen here as generic knowledge sources; (b) the multiplicity of states in data sources, handled through the hierarchical composition of independently defined domain objects, each accounting for all states in one well-known observational dimension. This simplification leaves modelers free to work with the bare conceptual bones of the problem, encapsulating complexities connected to data format, and scale. I will then describe the design of a software system that implements the approach, referring to explicit ontologies to unambiguously characterize the semantics of the objects of study, and allowing the independent definition of a global observation context that can be redefined as required. I will briefly discuss applications to multi-scale, multi-paradigm modeling, intelligent database design, and web-based collaboration.     

A Rigorous Architectural Approach to Adaptive Software Engineering

The engineering of distributed adaptive software is a complex task which requires a rigorous approach. Software architectural (structural) concepts and principles are highly beneficial in specifying, designing, analysing, constructing and evolving distributed software. A rigorous architectural approach dictates formalisms and techniques that are compositional, components that are context independent and systems that can be constructed and evolved incrementally. This paper overviews some of the underlying reasons for adopting an architectural approach, including a brief “rational history” of our research work, and indicates how an architectural model can potentially facilitate the provision of self-managed adaptive software system. Much of the research has been supported by the Engineering and Physical Sciences Research Council and is currently partly supported by EPSRC Platform grant AEDUS 2 and a DTC grant.