Lissa Pollacia

Simulation Of The Object Flow Model: A Conceptual Modeling Language For Object-driven Applications

The Object Flow Model (OFM) has been developed as a conceptual modeling language (CML) for object-driven (i.e. datadriven, object-oriented) applications. The model includes an object-oriented database that provides both a semantic data model to describe the stnrcture of complex objects and local methods associated with the classes appearing in the class hiermhy. The major contribution of the OFM is the dynamic modeling component called the Object Flow Diagram. Process steps are displayed in a directed graph; pmesses are trigered by the availability of the relevant objects that satisfy the guard The OFD was inspired by network-base4 process-oriented, discrete event simulation but adopts formal semantics associated with a deductive database rule language. This paper presents the OFM and discusses the suitability of the model to serve as a simulation model for an application as well as various possibilities for implementing an OFM simulator. This research clearly demonstrates that a simulation language with the power of the OFM should be implemented using both traditional event list technology (to handle the unconditional events) combined with qeert systemstyle matching technology to handle guard enforcement.

Web-Based Delivery of Information Technology Courses

The current American education system is faced with shifting market patterns resulting from rapid changes in the technologies designed to enhance the delivery of education. Todays university is vastly different from the institutions of twenty years ago. Technologys influence is changing the way we teach, the way we conduct research, and the way we seek to provide increased education opportunities without increased budgets. In answering this challenge, many departments of Information Technology are beginning to develop programs to offer courses using Web-based delivery, i.e., via the “virtual classroom.” In this article, we offer background and insight into the key elements involved with creating a virtual classroom, a discussion of the activities associated with the development of an online Information Technology course, and some of our observations concerning the impact of the online paradigm based on our own experience.

The object flow model for data-based simulation

This paper introduces the notion of data-based simulation to describe simulations where the basic entities and timing for the simulation are provided by explicitly captured data, e.g., in a database. This is in contrast to traditional simulation where entities are usually generated when needed, according to the appropriate distributions. This paper also introduces the Object Flow Model, where a single model can serve as the basis for the application software, for dam-based simulation, and for traditional simulation. The Object Flow Model uses an object-oriented database to describe entities and methods for manipulating entities and provides a visual formalism called the Object Flow Diagram (based on network-based process-oriented discrete event simulation languages), to describe the dynamic processing of an application. A data-based simulator for the Object Flow Model has been implemented for an apparel manufacturing shop floor based on data captured from a real-time payroll system to provide detailed, near-term advice for the shop floor manager.