Integrating Transaction Services into Web-based Software Development Environments

Software Development Environments (SDE) require sophisticated database transaction models due to the long-duration,interactive, and cooperative nature of the software engineering activities. Such Extended Transaction Models (ETM) have been proposed and implemented by building application-specific databases for the SDEs. With the development of World Wide Web (WWW), there have been a number of efforts to build SDEs on top of the WWW. Using web servers as the databases to store the software artifacts provided us with a new challenge: how to implement the ETMs in such web-based SDEs without requiring the web servers to be customized specifically according to the application domains of the SDEs. This paper presents our experiences of integrating transaction services into web based SDEs. We evolved from the traditional approach of building a transaction management component that operated on top of a dedicated database to the external transaction server approach. A transaction server, called JPernLite, was built to operate independently of the web servers and provide the necessary extensibility for SDEs to implement their ETMs. The transaction server can be integrated into the SDE via a number of interfaces, and we discuss the pros and cons of each alternative in detail

Exploiting method semantics in client cache consistency protocols for object-oriented databases

PhD ThesisData-shipping systems are commonly used in client-server object-oriented databases. This is in- tended to utilise clients' resources and improve scalability by allowing clients to run transactions locally after fetching the required database items from the database server. A consequence of this is that a database item can be cached at more than one client. This therefore raises issues regarding client cache consistency and concurrency control. A number of client cache consistency protocols have been studied, and some approaches to concurrency control for object-oriented datahases have been proposed. Existing client consistency protocols, however, do not consider method semantics in concurrency control. This study proposes a client cache consistency protocol where method se- mantic can be exploited in concurrency control. It identifies issues regarding the use of method semantics for the protocol and investigates the performance using simulation. The performance re- sults show that this can result in performance gains when compared to existing protocols. The study also shows the potential benefits of asynchronous version of the protoco

Object Oriented Terrain Databases For Visual Simulators

Report on a project to develop methodologies and solutions to the problem of representation and utilization of dynamic terrain on a real-time simulator

A comprehensive part model and graphical schema representation for object-oriented databases

Part-whole modeling plays an important role in the development of database schemata in data-intensive application domains such as manufacturing, design, computer graphics. text document processing, and so on. Object-oriented databases (OODBs) have been targeted for use in such areas. Thus, it is essential that OODBs incorporate a part relationship as one of their modeling primitives. In this dissertation, we present a comprehensive OODB part model which expands the boundaries of OODB part-whole modeling along three fronts. First, it identifies and codifies new semantics for the OODB part relationship. Second, it provides two novel realizations for part relationships and their associated modeling constructs in the context of OODB data models. Third. it, provides an extensive graphical notation for the development of OODB schemata. The heart of the part model is a part relationship that imposes part-whole interaction on the instances of an OODB. The part relationship is divided into four characteristic dimensions: (1) exclusive/shared. (2) cardinality/ordinality, (3) dependency. and (A) value propagation. The latter forms the basis for the definition of derived attributes in a part hierarchy. To demonstrate the viability of our part model, we present two novel realizations for it in the context of existing OODBs. The first realizes the part relationship as an object class and utilizes only a basic set of OODB constructs. The second realization, an implementation of which is described in this dissertation, uses the unique metaclass mechanism of the VODAK Model Language (VML). This implementation shows that our part model can be incorporated into an existing OODB without having to rewrite a substantial subsystem of the OODB, and it also shows that the VML metaclass facility can indeed support extensions in terms of new semantic relationships. To facilitate the creation of part-whole schemata, we introduce an extensive graphical notation for the part relationship and its associated constructs. This notation complements our more general OODB graphical schema representation which includes symbols for classes, attributes. methods. and a variety of relationships. OO-dini, a graphical schema editor that employs our notation and supports conversion of the graphical schema into textual formats, is also discussed

Natural language processing and advanced information management

Integrating diverse information sources and application software in a principled and general manner will require a very capable advanced information management (AIM) system. In particular, such a system will need a comprehensive addressing scheme to locate the material in its docuverse. It will also need a natural language processing (NLP) system of great sophistication. It seems that the NLP system must serve three functions. First, it provides an natural language interface (NLI) for the users. Second, it serves as the core component that understands and makes use of the real-world interpretations (RWIs) contained in the docuverse. Third, it enables the reasoning specialists (RSs) to arrive at conclusions that can be transformed into procedures that will satisfy the users' requests. The best candidate for an intelligent agent that can satisfactorily make use of RSs and transform documents (TDs) appears to be an object oriented data base (OODB). OODBs have, apparently, an inherent capacity to use the large numbers of RSs and TDs that will be required by an AIM system and an inherent capacity to use them in an effective way

Integrated persistent object manager (IPOM) : a model to support persistence and data sharing in object-oriented database systems

Computer Scienc