568,140 research outputs found
Embedding object-oriented design in system engineering
The Unified Modeling Language (UML) is a collection of techniques intended to document design decisions about software. This contrasts with systems engineering approaches such as for exampleStatemate and the Yourdon Systems Method (YSM), in which the design of an entire system consisting of software and hardware can be documented. The difference between the system- and the software level is reflected in differences between execution semantics as well as in methodology. In this paper, I show how the UML can be used as a system-level design technique. I give a conceptual framework for engineering design that accommodates the system- as well as the software level and show how techniques from the UML and YSM can be classified within this framework, and how this allows a coherent use of these techniques in a system engineering approach. These ideas are illustrated by a case study in which software for a compact dynamic bus station is designed. Finally, I discuss the consequences of this approach for a semantics of UML constructs that would be appropriate for system-level design
Towards a general object-oriented software development methodology
An object is an abstract software model of a problem domain entity. Objects are packages of both data and operations of that data (Goldberg 83, Booch 83). The Ada (tm) package construct is representative of this general notion of an object. Object-oriented design is the technique of using objects as the basic unit of modularity in systems design. The Software Engineering Laboratory at the Goddard Space Flight Center is currently involved in a pilot program to develop a flight dynamics simulator in Ada (approximately 40,000 statements) using object-oriented methods. Several authors have applied object-oriented concepts to Ada (e.g., Booch 83, Cherry 85). It was found that these methodologies are limited. As a result a more general approach was synthesized with allows a designer to apply powerful object-oriented principles to a wide range of applications and at all stages of design. An overview is provided of this approach. Further, how object-oriented design fits into the overall software life-cycle is considered
Guide to object-oriented analysis and design
The purpose of this guide is to provide Marshall Space Flight Center personnel with guidelines for the use of object-oriented analysis and design and to describe how it can be accomplished within the framework of existing development directives, including the Software Development Plan. It is not intended as a detailed tutorial. The reader is referred to the Coad and Yourdon texts in the References
A comparative analysis of data redundancy and execution time between relational and object oriented schema table
The design of database is one of the important parts in building software, because
database is the data storage inside the system. There are some techniques that allow
the programmer to improve design of the database. One of the most popular
techniques being used for database is the relational technique, which content entity
relationship diagram and normalization. The relational technique is easy to use and
useful for reducing data redundancy because the normalization technique solves the
data redundancy by applying normalization normal forms on the schema tables. The
second technique is the object oriented technique, which content class diagram and
generate schema table. An advantage of object oriented technique is its closeness to
programming languages like C++ or C#. This project is starting with applying
relational technique and object oriented technique to define which technique uses
less data redundancy during design database. Based on experimental results for total
data redundancy in HMS case study was 336 for relational technique and 364 for
object oriented technique as well as, course database case study was 186 for
relational technique and 204 for object oriented technique. Also, this project is focus
on query execution time between relational databases and object oriented database by
using user friendly window. The experimental result for query execution time in
HMS case study was 107.25 milliseconds for RDBMS and 80.5 milliseconds for
OODBMS. In course database case study was 46.75 milliseconds for RDBMS and
31.75 milliseconds for OODBMS. However, the comparative analysis in this project
is explaining the result of comparison between relational and object oriented
techniques specifically with data redundancy and query execution time
Object oriented development of engineering software using CLIPS
Engineering applications involve numeric complexity and manipulations of a large amount of data. Traditionally, numeric computation has been the concern in developing an engineering software. As engineering application software became larger and more complex, management of resources such as data, rather than the numeric complexity, has become the major software design problem. Object oriented design and implementation methodologies can improve the reliability, flexibility, and maintainability of the resulting software; however, some tasks are better solved with the traditional procedural paradigm. The C Language Integrated Production System (CLIPS), with deffunction and defgeneric constructs, supports the procedural paradigm. The natural blending of object oriented and procedural paradigms has been cited as the reason for the popularity of the C++ language. The CLIPS Object Oriented Language's (COOL) object oriented features are more versatile than C++'s. A software design methodology based on object oriented and procedural approaches appropriate for engineering software, and to be implemented in CLIPS was outlined. A method for sensor placement for Space Station Freedom is being implemented in COOL as a sample problem
An environment for object-oriented real-time system design
A concise object-oriented method for the development of real-time systems has been composed. Hardware components are modelled by (software) base objects; base objects are controlled by a hierarchy of coordinator objects, expressed in an organizational diagram. The behaviour of objects is specified by state transition diagrams. This approach considerably promotes requirements analysis and communication with the customer. A CASE tool has been constructed with diagram editors for graphical specifications of real-time systems. The tool can generate executable code for PLCs from these graphical specifications; reuse of previous results is supported by the repository function of the tool. Experiences attained in practice with method and tool show that time spent in system testing and installation is reduced considerabl
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