97 research outputs found
Innovative Evaluation System – IESM: An Architecture for the Database Management System for Mobile Application
As the mobile applications are constantly facing a rapid development in the recent years especially in the academic environment such as student response system [1-8] used in universities and other educational institutions; there has not been reported an effective and scalable Database Management System to support fast and reliable data storage and retrieval. This paper presents Database Management Architecture for an Innovative Evaluation System based on Mobile Learning Applications. The need for a relatively stable, independent and extensible data model for faster data storage and retrieval is analyzed and investigated. It concludes by emphasizing further investigation for high throughput so as to support multimedia data such as video clips, images and documents
Object oriented database management systems
Modern data intensive applications, such as multimedia systems require the ability to store and manipulate complex data. The classical Database Management Systems (DBMS), such as relational databases, cannot support these types of applications efficiently. This dissertation presents the salient features of Object Database Management Systems (ODBMS) and Persistent Programming Languages (PPL), which have been developed to address the data management needs of these difficult applications. An 'impedance mismatch' problem occurs in the traditional DBMS because the data and computational aspects of the application are implemented using two different systems, that of query and programming language. PPL's provide facilities to cater for both persistent and transient data within the same language, hence avoiding the impedance mismatch problem. This dissertation presents a method of implementing a PPL by extending the language C++ with pre-compiled classes. The classes are first developed and then used to implement object persistence in two simple applications.ComputingM. Sc. (Information Systems
Towards implementing integrated building product libraries
Electronic product catalogues and brochures are gaining
popularity but there is little agreement on content, format and
searching methods. This limits their usability and integration with
existing construction software tools. This paper examines a productmodelling
approach to delivering building product information and
describes a proposed multi-tier client-server environment. ISO/STEP
and IAI/IFC building product models are considered to facilitate
representation, exchange and sharing of product information. The
proposed architecture incorporates scalability with middleware
components that would provide single or few points of entry to
integrated product information. This paper is part of a research
project, which builds on the results of related projects including
ConstructIT Strategy, PROCAT-GEN, Active Catalog, COMBINE and ARROW,
towards implementing the required software components
Serving Massive Time-Based Media (SMaTBaM) - Report on the evaluation process of system needs and demands of serving time -based media in the area of the Performing Arts
The SMaTBaM project (Serving Massive Time-Based Media) aimed to establish a working example of a dataserver for time-based media in the area of the Performing Arts. Building on experience gained in the UMI/NetMuse project, the project will demonstrate the searching and serving of massive realtime data, using a web-based interactive front end.
The project is designed directly to enhance the Performing Arts Data Service, PADS , whose remit and funding from the Arts and Humanities Data Service, AHDS, do not extend to conducting research into the development of specialized supporting technology. (PADS is a Glasgow University Arts Planning Unit Project based in the Departments of Music and of Theatre, Film and Television Studies.
Engineering Enterprise Software Systems with Interactive UML Models and Aspect-Oriented Middleware
Large scale enterprise software systems are inherently complex and hard to maintain. To deal with this complexity, current mainstream software engineering practices aim at raising the level of abstraction to visual models described in OMG’s UML modeling language. Current UML tools, however, produce static design diagrams for documentation which quickly become out-of-sync with the software, and thus obsolete. To address this issue, current model-driven software development approaches aim at software automation using generators that translate models into code. However, these solutions don’t have a good answer for dealing with legacy source code and the evolution of existing enterprise software systems. This research investigates an alternative solution by making the process of modeling more interactive with a simulator and integrating simulation with the live software system. Such an approach supports model-driven development at a higher-level of abstraction with models without sacrificing the need to drop into a lower-level with code. Additionally, simulation also supports better evolution since the impact of a change to a particular area of existing software can be better understood using simulated “what-if” scenarios. This project proposes such a solution by developing a web-based UML simulator for modeling use cases and sequence diagrams and integrating the simulator with existing applications using aspect-oriented middleware technology
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A Systematic Performance Study of Object Database Management Systems
Many previous performance benchmarks for Object Database Management Systems (ODBMSs) have typically used arbitrary sets of tests based on what their designers felt were the characteristics of Engineering applications. Increasingly, however, ODBMSs are being used in non-engineering domains, such as Financial Trading, Clinical Healthcare, Telecommunications Network Management, etc. Part of the reason for this is that the technology has matured over the past few years and has become a less risky choice for organisations looking for better w'ays to manage complex data. However, the development of suitable application- or industry-specific benchmarks, based on actual performance studies, has not paralleled this growth.
The research reported here approaches performance evaluation of ODBMSs pragmatically. It uses a combination of case studies and benchmark experiments to investigate the performance characteristics of ODBMSs for particular applications, following the successful use of this approach by Youssef [Youss93] for studying the performance of On- Line Transaction Processing (OLTP) applications for Relational Database Management Systems (RDBMSs).
Six case studies at five organisations show’ that organisations consider a wide range of factors when undertaking their own performance studies or benchmarks. Furthermore, none of the studied organisations considered using any public benchmarks. Six current and derived benchmarks also highlight statistically significant performance differences between three major commercial products: Objectivity/DB, ObjectStore and UniSQL. These benchmarks indicate the suitability of the products tested for particular application domains.
The research could not find any evidence at this time to support the concept of a generic or canonical performance workload for ODBMSs. This is demonstrated by the case studies and supported by the benchmark experiments. However, the research shows that performance benchmarks serve a very useful role in ODBMS evaluations and can help identify architectural and quality problems with products that would not otherwise be observed until significant application or system development was already in progress
The advantages and cost effectiveness of database improvement methods
Relational databases have proved inadequate for supporting new classes of
applications, and as a consequence, a number of new approaches have been taken
(Blaha 1998), (Harrington 2000). The most salient alternatives are denormalisation
and conversion to an object-oriented database (Douglas 1997). Denormalisation
can provide better performance but has deficiencies with respect to
data modelling. Object-oriented databases can provide increased performance
efficiency but without the deficiencies in data modelling (Blaha 2000).
Although there have been various benchmark tests reported, none of these
tests have compared normalised, object oriented and de-normalised databases.
This research shows that a non-normalised database for data containing type
code complexity would be normalised in the process of conversion to an objectoriented
database. This helps to correct badly organised data and so gives the
performance benefits of de-normalisation while improving data modelling.
The costs of conversion from relational databases to object oriented databases
were also examined. Costs were based on published benchmark tests, a
benchmark carried out during this study and case studies. The benchmark tests
were based on an engineering database benchmark. Engineering problems such as
computer-aided design and manufacturing have much to gain from conversion to
object-oriented databases. Costs were calculated for coding and development, and
also for operation. It was found that conversion to an object-oriented database was
not usually cost effective as many of the performance benefits could be achieved
by the far cheaper process of de-normalisation, or by using the performance
improving facilities provided by many relational database systems such as
indexing or partitioning or by simply upgrading the system hardware.
It is concluded therefore that while object oriented databases are a better
alternative for databases built from scratch, the conversion of a legacy relational
database to an object oriented database is not necessarily cost effective
Hybrid semantic-document models
This thesis presents the concept of hybrid semantic-document models to aid information management when using standards for complex technical domains such as military data communication. These standards are traditionally text based documents for human interpretation, but prose sections can often be ambiguous and can lead to discrepancies and subsequent implementation problems. Many organisations produce semantic representations of the material to ensure common understanding and to exploit computer aided development. In developing these semantic representations, no relationship is maintained to the original prose. Maintaining relationships between the original prose and the semantic model has key benefits, including assessing conformance at a semantic level, and enabling original content authors to explicitly define their intentions, thus reducing ambiguity and facilitating computer aided functionality.
Through the use of a case study method based on the military standard MIL-STD-6016C, a framework of relationships is proposed. These relationships can integrate with common document modelling techniques and provide the necessary functionality to allow semantic content to be mapped into document views. These relationships are then generalised for applicability to a wider context. Additionally, this framework is coupled with a templating approach which, for repeating sections, can improve consistency and further enhance quality. A reflective approach to model driven web rendering is presented and evaluated. This reflective approach uses self-inspection at runtime to read directly from the model, thus eliminating the need for any generative processes which result in data duplication across source used for different purpose
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