An Object Oriented Paradigm for Requirements Specifications.

Software engineering defines a formalized five-step life-cycle for software development. These steps are: requirements specification, design, implementation, testing and maintenance. The requirements specification phase of the software development life-cycle is responsible for determining the functionality of the proposed system. In this work, a methodology is developed that enhances the generation of accurate requirements specifications, utilizing an object-oriented paradigm. This research realizes four objectives. First, the process of information transferral between the user and the specification team is enhanced. Second, a working base of knowledge containing the domain-specific information within the initial requirements document is established for use by the specification team. Third, techniques for evaluating the overall quality of the initial requirements document are addressed. Specifically, the problems associated with document ambiguity, completeness, consistency and structure are examined. Finally, a specification paradigm is defined utilizing this knowledge-based specification environment. The paradigm permits the automatic generation of an object-oriented specification model. This model may then be used as an input for the design phase. This paradigm defines a methodology for the establishment and evaluation of the knowledge-based specification environment. The environment permits the incorporation of an object-oriented development strategy into the specification process. In addition, the concept of information traceability throughout the specification process is enhanced

The utilization of neural nets in populating an object-oriented database

Existing NASA supported scientific data bases are usually developed, managed and populated in a tedious, error prone and self-limiting way in terms of what can be described in a relational Data Base Management System (DBMS). The next generation Earth remote sensing platforms (i.e., Earth Observation System, (EOS), will be capable of generating data at a rate of over 300 Mbs per second from a suite of instruments designed for different applications. What is needed is an innovative approach that creates object-oriented databases that segment, characterize, catalog and are manageable in a domain-specific context and whose contents are available interactively and in near-real-time to the user community. Described here is work in progress that utilizes an artificial neural net approach to characterize satellite imagery of undefined objects into high-level data objects. The characterized data is then dynamically allocated to an object-oriented data base where it can be reviewed and assessed by a user. The definition, development, and evolution of the overall data system model are steps in the creation of an application-driven knowledge-based scientific information system

Management, design and developement of a mesh generation environment using open source software

In this paper we present an object oriented implementation of a general-purpose mesh generation environment for geometry-based simulations. The aim of this application is to unify available legacy code and new research algorithms in only one mesh generation suite. We focus in two aspects that can be of the general interest for managers, designers and developers of similar projects. On the one hand, we analyze the software engineering practices that we have followed in the management and development process. In addition, we detail and discuss the Open Source tools and libraries that we have used. On the other hand, we discuss the design and the data structure of the environment. In particular, we first summarize the topological and geometrical representation. Second, we detail our implementation of the hierarchical mesh generation structure. Third we present our design to mediate collaboration between classes. Finally, we present some of the mesh generation features to show the capabilities of the environment

Expert system decision support for low-cost launch vehicle operations

Progress in assessing the feasibility, benefits, and risks associated with AI expert systems applied to low cost expendable launch vehicle systems is described. Part one identified potential application areas in vehicle operations and on-board functions, assessed measures of cost benefit, and identified key technologies to aid in the implementation of decision support systems in this environment. Part two of the program began the development of prototypes to demonstrate real-time vehicle checkout with controller and diagnostic/analysis intelligent systems and to gather true measures of cost savings vs. conventional software, verification and validation requirements, and maintainability improvement. The main objective of the expert advanced development projects was to provide a robust intelligent system for control/analysis that must be performed within a specified real-time window in order to meet the demands of the given application. The efforts to develop the two prototypes are described. Prime emphasis was on a controller expert system to show real-time performance in a cryogenic propellant loading application and safety validation implementation of this system experimentally, using commercial-off-the-shelf software tools and object oriented programming techniques. This smart ground support equipment prototype is based in C with imbedded expert system rules written in the CLIPS protocol. The relational database, ORACLE, provides non-real-time data support. The second demonstration develops the vehicle/ground intelligent automation concept, from phase one, to show cooperation between multiple expert systems. This automated test conductor (ATC) prototype utilizes a knowledge-bus approach for intelligent information processing by use of virtual sensors and blackboards to solve complex problems. It incorporates distributed processing of real-time data and object-oriented techniques for command, configuration control, and auto-code generation

Strategy development for object-oriented multiblock grid generation and adaptation to complex geometries

The first part of the thesis deals with the strategy development for multiblock structured grid generation to complex geometries. Based on the grid generation practices over years, a set of grid construction rules is developed to provide the CFD engineer an object-oriented method for grid design. The essential core of the object-oriented method is to decompose a complex meshing task into a set of sub-tasks, which are treated individually at a lower level of both geometry and topology. The grid construction rules cover the questions of dealing with selection of meshing direction, generation of surface description and block topology building. To explain this grid design method, an example, dealing with a highly complex geometry, is demonstrated. The second part of the thesis deals with the strategy development for multiblock structured grid adaptation. Since a grid can be adapted with or without a flow solution, the terminologies passive and active grid adaptation are introduced to describe a solution-dependent or a solution-independent grid adaptation. Passive grid adaptation is performed by generating adequate block topologies, such that a local enrichment of grid points can be achieved. It consists of three concepts: one-dimensional clustering of grid lines, block encapsulation, and smart block. The method for solution-dependent grid adaptation is developed based on the idea of grid optimization. A grid is adapted by minimization of objective functions, in which relations among weight functions and grid line distribution are formulated. The measures for grid quality, such as smoothness, cell aspect ratio, and orthogonality, are formulated as control terms of the objective functions to improve grid quality. In addition, a concept of smart cell used for solution-dependent grid adaptation is proposed in this thesis

SCOS 2: ESA's new generation of mission control system

New mission-control infrastructure is currently being developed by ESOC, which will constitute the second generation of the Spacecraft Control Operations system (SCOS 2). The financial, functional and strategic requirements lying behind the new development are explained. The SCOS 2 approach is described. The technological implications of these approaches is described: in particular it is explained how this leads to the use of object oriented techniques to provide the required 'building block' approach. The paper summarizes the way in which the financial, functional and strategic requirements have been met through this combination of solutions. Finally, the paper outlines the development process to date, noting how risk reduction was achieved in the approach to new technologies and summarizes the current status future plans

Development of a client interface for a methodology independent object-oriented CASE tool : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Computer Science at Massey University

The overall aim of the research presented in this thesis is the development of a prototype CASE Tool user interface that supports the use of arbitrary methodology notations for the construction of small-scale diagrams. This research is part of the larger CASE Tool project, MOOT (Massey's Object Oriented Tool). MOOT is a meta-system with a client-server architecture that provides a framework within which the semantics and syntax of methodologies can be described. The CASE Tool user interface is implemented in Java so it is as portable as possible and has a consistent look and feel. It has been designed as a client to the rest of the MOOT system (which acts as a server). A communications protocol has been designed to support the interaction between the CASE Tool client and a MOOT server. The user interface design of MOOT must support all possible graphical notations. No assumptions about the types of notations that a software engineer may use can be made. MOOT therefore provides a specification language called NDL for the definition of a methodology's syntax. Hence, the MOOT CASE Tool client described in this thesis is a shell that is parameterised by NDL specifications. The flexibility provided by such a high level of abstraction presents significant challenges in terms of designing effective human-computer interaction mechanisms for the MOOT user interface. Functional and non-functional requirements of the client user interface have been identified and applied during the construction of the prototype. A notation specification that defines the syntax for Coad and Yourdon OOA/OOD has been written in NDL and used as a test case. The thesis includes the iterative evaluation and extension of NDL resulting from the prototype development. The prototype has shown that the current approach to NDL is efficacious, and that the syntax and semantics of a methodology description can successfully be separated. The developed prototype has shown that it is possible to build a simple, non-intrusive, and efficient, yet flexible, useable, and helpful interface for meta-CASE tools. The development of the CASE Tool client, through its generic, methodology independent design, has provided a pilot with which future ideas may be explored

Multicomputers

This report outlines the history, current status, current developments, and plans for the message-passing concurrent computers, or multicomputers, developed in the Submicron Systems Architecture Project at Caltech. These systems include the Cosmic Cube and its commercial descendants, two second-generation cosmic cubes currently in development, and the Mosaic C, a fine grain multicomputer whose nodes are single VLSI chips. Section 1 introduces the physical architectures, with particular attention to the characteristics of the message-passing networks. Section 2 describes the programming environments for the first and second generation medium grain size "cubes." Section 3 describes a fine grain concurrent object-oriented programming notation called Cantor, which currently runs on cubes and sequential systems, and which will be used for application programming of the Mosaic C

Veamy: an extensible object-oriented C++ library for the virtual element method

This paper summarizes the development of Veamy, an object-oriented C++ library for the virtual element method (VEM) on general polygonal meshes, whose modular design is focused on its extensibility. The linear elastostatic and Poisson problems in two dimensions have been chosen as the starting stage for the development of this library. The theory of the VEM, upon which Veamy is built, is presented using a notation and a terminology that resemble the language of the finite element method (FEM) in engineering analysis. Several examples are provided to demonstrate the usage of Veamy, and in particular, one of them features the interaction between Veamy and the polygonal mesh generator PolyMesher. A computational performance comparison between VEM and FEM is also conducted. Veamy is free and open source software