John V. Harrison

Integrating Active and Deductive Rules

This paper describes how active and deductive rules can be integrated to form an expressive representation for declaring and reasoning about events and conditions. Specifically, this paper describes an extension and optimizations to the PF algorithm, which detects events, i.e. updates, that affect derived relations (or views), even when the derived relation is recursively defined. This capability improves the expressiveness of the event-condition-action (ECA) rules, which can then be used to detect more complex events and express conditions that reason with the updates to both stored and derived relations. The updates to the derived relations can be detected without having to materialize the derived relations. The PF algorithm can detect these updates when certain modifications to the definition of the derived relation are made. This approach has been implemented to form an event detector and condition evaluator for an active deductive database. These enhancements increase the sophistication of an active database since ECA rules can be defined that react to a larger scope of real-world situations.

Enhancing software development project courses via industry participation

Many computer science departments offer a course that features a software development project where students work as part of a team. An objective of this type of course is to simulate an industrial development environment thereby allowing students to experience some of the dynamics that they will encounter after completion of their study. The accuracy of the simulation can be improved, and hence the educational experienced enhanced, by the incorporation of industry participation directly into the course. Difficulties in organising and administering the project in the context of industry participation can occur in practice, which serve to deter the incorporation. This paper motivates industry participation in a team project course by identifying the potential benefits for the students, some of which are implicit, and also those for the industry sponsor, lecturer and host academic institution. A methodology for incorporating industry participation, which can be employed to overcome the difficulties in achieving these benefits, is presented. A model for administering a team project course in the context of industrial participation, which includes the use of an intranet as an enabling technology, is also described. The methodology and model, which have been employed successfully, can be utilised to improve the quality of the educational experience resulting from team project software development courses.

An emerging marketplace for digital advertising based on amalgamated digital signage networks

Digital signage networks are a newly emerging form of electronic advertising technology that is rapidly growing in popularity but has received little attention in e-commerce (electronic commerce) literature. We motivate the cost reduction and increased effectiveness of advertising that is displayed and managed using digital signage networks as opposed to traditional signage. We introduce a partially automated intermediary, namely the digital signage exchange that forms a virtual marketplace for the purchase and sale of display time on the digital signage network. We present a concise representation for a customers order for display time on the digital signage network and an informal business transaction management model for the exchange. This model includes support for advance bulk purchase of blocks of display time. It can also make a counter-offer to the customer when an order cannot be completely fulfilled as requested.

Enhancing digital advertising using dynamically configurable multimedia

Digital signage networks are a newly emerging form of multimedia advertising technology that is rapidly growing in popularity but has received little attention in multimedia literature. In this paper we motivate the cost reduction and increased effectiveness of advertising that is displayed and managed using digital signage networks as opposed to traditional signage. As an example, we describe a method for customizing advertising messages for particular demographics in different locations using dynamically configurable multimedia. We describe a partially automated intermediary, namely the digital signage exchange, which forms a virtual marketplace for the purchase and sale of multimedia advertising on the digital signage network.

Active rules in deductive databases

John V, Harrison Department of Computer Science University of Queensland Brisbanej QLD, 4072 Australia Active database systems react to pre-defined situations automatically without user intervention. The system detects when events occur and then triggers an action if a user-defined condition is satisfied. The types of events that can be detected and the expressiveness of the userdefined conditions are metrics of sophistication of an active database as they define the scope of real-world situations that can cause the system to react. This paper describes a situation monitor for an active database that can detect events affecting derived relations, as well as stored relations. The derived relations do not need to be materialized even if recursively defined or if the definition of the relations are modified. A novel representation for conditions that can express both states of stored relations as well as the implied states of the derived relations is described. The representation can be used to reason with the events to the stored relations as well as the detected events to the derived relations. The approach has been implemented to detect events and evaluate conditions for a prototype active deductaue database.

Automated Reverse Engineering of Legacy 4GL Information System Applications Using the ITOC Workbench

Most contemporary fourth-generation languages (4GLs) are tightly coupled with the relational database and other subsystems provided by the vendor. As a result, organisations wishing to change database vendors are typically forced to rewrite their applications using the new vendors 4GL. The anticipated cost of this redevelopment can deter an organisation from changing vendors, hence denying it the benefits that would otherwise result, for example, the exploitation of more sophisticated database technology. If tools existed that could reduce the rewriting effort, the option of changing database vendors would become more economically feasible.

Evaluation of the ITOC information system design recovery tool

Design recovery from legacy information systems is an industrially relevant problem which poses significant research challenges. However, although many approaches have been proposed, few of these have been implemented beyond a prototype stage which makes it difficult to evaluate their effectiveness. The Ingres to Oracle Conversion (ITOC) project is a large collaborative research initiative between The University of Queensland and Oracle Corporation to design and implement a tool that automatically recovers both the application structure and the static schema definition of Ingres 4GL applications. The results of this analysis are then loaded into Oracles CASE tool. The paper describes the basic techniques used by the ITOC tool which includes data flow analysis, query analysis and simple data mining. The effectiveness of these techniques when applied to real commercial applications is then evaluated in detail.

An integrated database reengineering architecture-a generic approach

Methods and tools have been proposed and developed to facilitate database design recovery under the framework of reverse engineering and reengineering. These tools and methods are usually limited to a particular scenario and requirement. They are not adaptive, or general enough, to suit other scenarios. In most cases, new tools and methods will have to be redeveloped to suit these scenarios. This can result in a tremendous waste of effort and cost. In this paper we describe an integrated generic architecture for reengineering legacy databases. The goal of this research is to formalize an integrated generic architecture that is applicable to different database reengineering scenarios and requirements. We examine the conceptual and technical requirement for enabling such an architecture. An overview of the database reengineering process, which serves as a guideline for practitioners and tool developers, is presented. The results of a preliminary feasibility study based on the results of an implementation of relational database reverse engineering tools within the content of the architecture is also provided.

Data flow analysis within the ITOC information system design recovery tool

Most contemporary fourth-generation languages (4GL) are tightly coupled with the database server, and other subsystems, that are provided by the vendor. As a result organizations that wish to change database vendors are typically forced to rewrite their applications using the new vendors 4GL. The anticipated cost of this redevelopment can deter an organization from changing vendors, hence denying it the benefits that would otherwise result, e.g., the exploitation of more sophisticated database server technology. If tools existed that could reduce the rewriting effort, the large upfront cost of migrating the organizations applications would also be reduced, which could make the transition economically feasible. The ITOC project is part of a large collaborative research initiative between the Centre for Software Maintenance at the University of Queensland and Oracle Corporation. The objective of this project is to design and implement a tool that automatically recovers both the application structure and the static schema definition of 4GL information system applications. These recovered system components are transformed into constructs that populate Oracles Designer 2000 CASE repository. An essential component of the ITOC process is to determine the relationships between different columns in the database and between references to those columns and fields that appear within the user interface. This in turn requires analysis of data flow between variables in the 4GL programs. While data flow analysis has been applied in many applications, for example, code optimization and program slicing, this paper presents the results of using data flow analysis in the construction of a novel design recovery tool for 4GL-based information.

Incremental view maintenance in extended relational databases

This paper presents a method for efficiently computing updates to a view when relations appearing in the views definition are modified. Views that are defined using all of the relational operators, stratified negation and general recursion are considered. As a result, the method can be employed in both a traditional relational database system and also a deductive database system. The method can compute the updates without requiring access to a materialization of the view and is shown to be more efficient than related methods. The method can compute the updates even when the views definition is modified.