A Views-Based Design Framework for Web Applications

Web application design is a broad term that refers to any aspect of designing a Web application, including designing Web interfaces to data. There are a number of commercial software tools available that employ various techniques for implementing Web access to databases. However, these techniques apply only to portions of Web application implementation and lack a common design paradigm. We believe that defining an approach to designing and implementing Web applications based on views, frameworks, and patterns allows us to extend an object-oriented design representation and develop reusable and extensible design solutions for a class of Web applications in which the concerns are separated. The major contribution of this thesis is the development of a new approach to designing Web applications, producing the following visible contributions: a model for Web applications based upon a separation of concerns using views; a framework for system elements so that object-oriented design patterns can be used to build the application; a reusable design approach so that many Web applications can be built around the same framework; a coherent and organized framework representation using extended UML; and an implementation approach that can be implemented on a number of different platforms using a range of software and tools. In support of this solution, this thesis shows the design and implementation of a proof-of-concept Web application using this design technique. We believe that the approach to Web application design promoted in this thesis has proven itself useful in a practical way for the case studies discussed herein and points the way to a wider range of design and implementation possibilities

A generic neural network framework using design patterns

Designing object-oriented software is hard, and designing reusable object-oriented software is even harder. This task is even more daunting for a developer of computational intelligence applications, as optimising one design objective tends to make others inefficient or even impossible. Classic examples in computer science include ‘storage vs. time’ and ‘simplicity vs. flexibility.’ Neural network requirements are by their very nature very tightly coupled – a required design change in one area of an existing application tends to have severe effects in other areas, making the change impossible or inefficient. Often this situation leads to a major redesign of the system and in many cases a completely rewritten application. Many commercial and open-source packages do exist, but these cannot always be extended to support input from other fields of computational intelligence due to proprietary reasons or failing to fully take all design requirements into consideration. Design patterns make a science out of writing software that is modular, extensible and efficient as well as easy to read and understand. The essence of a design pattern is to avoid repeatedly solving the same design problem from scratch by reusing a solution that solves the core problem. This pattern or template for the solution has well understood prerequisites, structure, properties, behaviour and consequences. CILib is a framework that allows developers to develop new computational intelligence applications quickly and efficiently. Flexibility, reusability and clear separation between components are maximised through the use of design patterns. Reliability is also ensured as the framework is open source and thus has many people that collaborate to ensure that the framework is well designed and error free. This dissertation discusses the design and implementation of a generic neural network framework that allows users to design, implement and use any possible neural network models and algorithms in such a way that they can reuse and be reused by any other computational intelligence algorithm in the rest of the framework, or any external applications. This is achieved by using object-oriented design patterns in the design of the framework.Dissertation (MSc)--University of Pretoria, 2007.Computer Scienceunrestricte

A comparative evaluation of dynamic visualisation tools

Despite their potential applications in software comprehension, it appears that dynamic visualisation tools are seldom used outside the research laboratory. This paper presents an empirical evaluation of five dynamic visualisation tools - AVID, Jinsight, jRMTool, Together ControlCenter diagrams and Together ControlCenter debugger. The tools were evaluated on a number of general software comprehension and specific reverse engineering tasks using the HotDraw objectoriented framework. The tasks considered typical comprehension issues, including identification of software structure and behaviour, design pattern extraction, extensibility potential, maintenance issues, functionality location, and runtime load. The results revealed that the level of abstraction employed by a tool affects its success in different tasks, and that tools were more successful in addressing specific reverse engineering tasks than general software comprehension activities. It was found that no one tool performs well in all tasks, and some tasks were beyond the capabilities of all five tools. This paper concludes with suggestions for improving the efficacy of such tools

Real world evaluation of aspect-oriented software development : a thesis submitted in partial fulfilment of the requirements for the degree of Master of Science in Computer Science at Massey University, Palmerston North, New Zealand

Software development has improved over the past decade with the rise in the popularity of the Object-Oriented (OO) development approach. However, software projects continue to grow in complexity and continue to have alarmingly low rates of success. Aspect-Oriented Programming (AOP) is touted to be one solution to this software development problem. It shows promise of reducing programming complexity, making software more flexible and more amenable to change. The central concept introduced by AOP is the aspect. An aspect is used to modularise crosscutting concerns in a similar fashion to the way classes modularise business concerns. A crosscutting concern cannot be modularised in approaches such as OO because the code to realise the concern must be spread throughout the module (e.g. a tracing concent is implemented by adding code to every method in a system). AOP also introduces join points, pointcuts, and advice which are used with aspects to capture crosscutting concerns so they can be localised in a modular unit. OO took approximately 20 years to become a mainstream development approach. AOP was only invented in 1997. This project considers whether AOP is ready for commercial adoption. This requires analysis of the AOP implementations available, tool support, design processes, testing tools, standards, and support infrastructure. Only when AOP is evaluated across all these criteria can it be established whether it is ready to be used in commercial projects. Moreover, if companies are to invest time and money into adopting AOP, they must be aware of the benefits and risks associated with its adoption. This project attempts to quantify the potential benefits in adopting AOP, as well as identifying areas of risk. SolNet Solutions Ltd, an Information Technology (IT) company in Wellington, New Zealand, is used in this study as a target environment for integration of aspects into a commercial development process. SolNet is in the business of delivering large scale enterprise Java applications. To assist in this process they have developed a Common Services Architecture (CSA) containing components that can be reused to reduce risk and cost to clients. However, the CSA is complicated and SolNet have identified aspects as a potential solution to decrease the complexity. Aspects were found to bring substantial improvement to the Service Layer of SolNet. applications, including substantial reductions in complexity and size. This reduces the cost and time of development, as well as the risk associated with the projects. Moreover, the CSA was used in a more consistent fashion making the system easier to understand and maintain, and several crosscutting concerns were modularised as part of a reusable aspect library which could eventually form part of their CSA. It was found that AOP is approaching commercial readiness. However, more work is needed on defining standards for aspect languages and modelling of design elements. The current solutions in this area are commercially viable, but would greatly benefit from a standardised approach. Aspect systems can be difficult to test and the effect of the weaving process on Java serialisation requires further investigation

Pattern Reification as the Basis for Description-Driven Systems

One of the main factors driving object-oriented software development for information systems is the requirement for systems to be tolerant to change. To address this issue in designing systems, this paper proposes a pattern-based, object-oriented, description-driven system (DDS) architecture as an extension to the standard UML four-layer meta-model. A DDS architecture is proposed in which aspects of both static and dynamic systems behavior can be captured via descriptive models and meta-models. The proposed architecture embodies four main elements - firstly, the adoption of a multi-layered meta-modeling architecture and reflective meta-level architecture, secondly the identification of four data modeling relationships that can be made explicit such that they can be modified dynamically, thirdly the identification of five design patterns which have emerged from practice and have proved essential in providing reusable building blocks for data management, and fourthly the encoding of the structural properties of the five design patterns by means of one fundamental pattern, the Graph pattern. A practical example of this philosophy, the CRISTAL project, is used to demonstrate the use of description-driven data objects to handle system evolution.Comment: 20 pages, 10 figure

Database independent Migration of Objects into an Object-Relational Database

This paper reports on the CERN-based WISDOM project which is studying the serialisation and deserialisation of data to/from an object database (objectivity) and ORACLE 9i.Comment: 26 pages, 18 figures; CMS CERN Conference Report cr02_01

Strategic Directions in Object-Oriented Programming

This paper has provided an overview of the field of object-oriented programming. After presenting a historical perspective and some major achievements in the field, four research directions were introduced: technologies integration, software components, distributed programming, and new paradigms. In general there is a need to continue research in traditional areas:\ud (1) as computer systems become more and more complex, there is a need to further develop the work on architecture and design; \ud (2) to support the development of complex systems, there is a need for better languages, environments, and tools; \ud (3) foundations in the form of the conceptual framework and other theories must be extended to enhance the means for modeling and formal analysis, as well as for understanding future computer systems

Two Case Studies of Subsystem Design for General-Purpose CSCW Software Architectures

This paper discusses subsystem design guidelines for the software architecture of general-purpose computer supported cooperative work systems, i.e., systems that are designed to be applicable in various application areas requiring explicit collaboration support. In our opinion, guidelines for subsystem level design are rarely given most guidelines currently given apply to the programming language level. We extract guidelines from a case study of the redesign and extension of an advanced commercial workflow management system and place them into the context of existing software engineering research. The guidelines are then validated against the design decisions made in the construction of a widely used web-based groupware system. Our approach is based on the well-known distinction between essential (logical) and physical architectures. We show how essential architecture design can be based on a direct mapping of abstract functional concepts as found in general-purpose systems to modules in the essential architecture. The essential architecture is next mapped to a physical architecture by applying software clustering and replication to achieve the required distribution and performance characteristics

Designing Traceability into Big Data Systems

Providing an appropriate level of accessibility and traceability to data or process elements (so-called Items) in large volumes of data, often Cloud-resident, is an essential requirement in the Big Data era. Enterprise-wide data systems need to be designed from the outset to support usage of such Items across the spectrum of business use rather than from any specific application view. The design philosophy advocated in this paper is to drive the design process using a so-called description-driven approach which enriches models with meta-data and description and focuses the design process on Item re-use, thereby promoting traceability. Details are given of the description-driven design of big data systems at CERN, in health informatics and in business process management. Evidence is presented that the approach leads to design simplicity and consequent ease of management thanks to loose typing and the adoption of a unified approach to Item management and usage.Comment: 10 pages; 6 figures in Proceedings of the 5th Annual International Conference on ICT: Big Data, Cloud and Security (ICT-BDCS 2015), Singapore July 2015. arXiv admin note: text overlap with arXiv:1402.5764, arXiv:1402.575

Towards an aspect weaving BPEL engine

This position paper proposes the use of dynamic aspects and the visitor design pattern to obtain a highly configurable and extensible BPEL engine. Using these two techniques, the core of this infrastructural software can be customised to meet new requirements and add features such as debugging, execution monitoring, or changing to another Web Service selection policy. Additionally, it can easily be extended to cope with customer-specific BPEL extensions. We propose the use of dynamic aspects not only on the engine itself but also on the workflow in order to tackle the problems of Web Service hot deployment and hot fixes to long running processes. In this way, composing aWeb Service "on-the-fly" means weaving its choreography interface into the workflow