A structural active-object systems (SAOS) is a, transition-based object-oriented system consisting of a collection of interacting structural active objects (SAOs), which can be structurally and hierarchically composed from their component SAOs. The behaviors of SAOs are determined by the transition statements provided in their class definitions. Various concurrent systems such...
Existing graphics systems are too large for students to study in an introductory computer graphics course. We have implemented a lightweight, object-oriented graphics system called OGS for instruction. OGS is written in Java. It demonstrates how a graphics system is implemented from scratch and is intended to help students understand...
In this paper, we describe a software mechanism, a software channel, that allows a group of distributed objects to communicate with each other automatically once they are connected to it. Software channels and predesigned distributed objects that are connected to them encapsulate the communication protocol and the network topology to...
A Kalman filter was developed to recover information on short period variations of ocean circulation from the satellite altimeter signals for the North Pacific Ocean. The ocean circulation at each grid point is specified by three variables: sea level height h, zonal velocity u, and meridional velocity v. In our...
The SAOS Road Network Simulator (SARNS) is a graphical simulation program for transportation planning, implemented using the structural active-object system (SAOS) approach. A SAOS is an object-oriented concurrent system that consists of a collection of interacting structural active objects (SAOs), whose behaviors are determined by transition statements provided in their...
Forms are the most common means of interacting with databases. Database develop1;11ent products offer differing capabilities for creating forms. We will compare the form design features available using 4th Dimension and Oracle database products. These two products have the most complete set of features compared to other micro computer database...
Scheduling problem has both theoretical and practical interest. A great deal of research has been done in this field. In this paper we will use a local optimal search method to do job shop scheduling. This method will be compared with a constraint satisfaction method called Micro-boss. Other issues such...
The majority of database users interact with database systems by manipulating forms. This paper discusses the fundamental mechanisms underlying forms and considers how these mechanisms affect the behavior of forms. We then review the forms supported by commercial products. None of the packages reviewed provide all of the features that...
Data, buffering is an important mechanism to enhance performance of a database system. In this project, we studied the data buffering mechanism of the Oracle database system and created an Oracle data buffering simulation program in Java. The data obtained from the simulation program w re compared with the performance...
In a typical method of database design, ER diagrams are used to represent the conceptual schema of the database. Use-cases are now widely used to capture requirements in designing the basic architecture of an object-oriented system. Use-cases are highly effective in designing forms required for data insertion, retrieval, update, and...
Application supporting a Graphical User Interface (GUI) are difficult to create. Their inherent complexity, their interdependence with many other disciplines, and the inadequacy of the existing tools leave the programmer with too much to do. In particular, almost no help is provided to create application-specific code. Some visual formalisms such...
Little Smalltalk is a small, reasonably fast, easy-to-understand, easy-to-modify Smalltalk system. The system was originally developed in 1984 as a part of an implementation project to develop a minimal Smalltalk system, closely resembling Smalltalk-80. The system was developed in C. The current project is an experiment to port the Little...
We present a model for a distributed virtual market place that can be constructed on the Internet to support selling and buying requests, such as those found as classified advertisements. One requirement for a transaction to take place in the virtual market place is that a sell request and a...
We have developed SearchPak, a machine independent parallel searching tool on shared and distributed memory machines. It can be used for combinatorial optimization problems and OR-parallel computations as well. Both depth-first and best-first search of the state space can be performed using the SearchPak. With SearchPak, a user just provides...
Forms are an easy-to-use interface to access a database, including a remote database on the Internet. An entity-relationship (ER} diagram, which is a pictorial representation of a database schema, is widely used in designing a database. A class diagram, which shows set of classes, relationships among them, and associations, are...
Relational database systems have successfully solved many
business data processing problems. The primary reason of this
success is that the relational data model provides a simple, yet
flexible view of data as tables. In studying VLSI/CAD data, we noticed
that they are often represented in formats similar to relational
tuples....
An active object system is a transition-based object-oriented system suitable for the design of various concurrent systems. An AOS consists of a collection of interacting objects, where the behavior of each object is determined by the transition statements provided in the class of that object. A transition statement is a...
I introduce a compositional approach to application software development. In this approach, an extended entity-relationship diagram (EERD), which represents the component types and the relationship types within an application domain, is used as a template of executable programs in that application domain. As we use structural active objects as the...