Overview The past Introduction
6.4 The stage-wise and classical waterfall models conventional models
Because of the problems encountered with the unstructured approach of the build-and-fix model, several more detailed models were devised. The earliest of these models was the stage-wise model from which the classical waterfall model developed. The stage-wise model was developed in 1956 by Benington in an attempt to provide an engineering process to the development of software. It represents a unidirectional, sequential process – once a stage has been completed, the results of that stage become a fixed baseline from which the following stages develop – there is no revision. While this appears to be rather rigid and naïve, the development of a defined process at that time was a significant breakthrough in software engineering. It was soon recognised, however, that the sequential nature of the stage-wise model was causing problems and some form of reworking was required in order to allow a user’s needs to be addressed more effectively. For this reason the classical waterfall model was developed – shown in Figure 6.4. The classical waterfall model differed Figure 6.4 The classical waterfall model 120 Chapter 6 n Software development from the stage-wise model in that it allowed some limited iteration between stages – shown as ‘splashing back’ in Figure 6.4. Figure 6.2 highlights one of the main problems with the conventional waterfall-type approaches. As we move through the stages of the process the problem we are trying to solve is not static and moves on shown by the shifting problem ovals with respect to time in Figure 6.2. Thus, by the time we complete our analysis, design and building of the software system, the program we present to our user no longer solves the problem they currently have – i.e., the software is already obsolete. Another problem is that the user’s understanding of the problem is unclear and there are ambiguities in the subse- quent requirements specification. We cannot then guarantee that the system we design and develop is matching the user’s needs at all. The conventional approach to software development is, therefore, only really appropriate for projects that are: n short say six months to one year maximum – a typical student project length so that the problem does not have time to evolve; and n understood clearly – so that the initial requirements are captured accurately and subse- quent specifications and designs are very close matches with what is actually needed. You should, therefore, only use this approach for your own project if you are confident that you fully understand the requirements of the system or they have already been provided to you in an unambiguous way by the client. In most cases we cannot guarantee to fully understand the needs of our user – in which case one of the following approaches is perhaps more suitable for you to follow. •6.5 The incremental model
Rather than delivering your software to your client towards the end of your project in one ‘big bang’ as the conventional models do, it might be better to deliver the system to them as a series of intermediate working sub-systems over a period of time. Thus, you add more functionality to the software at each release of the system. This means that you need to get an overall software structure kernel in place as part of the first release of your system. The other parts of the system are then brought on-line and released to the user as the system is developed. Thus, each release to the user provides added functionality to the existing system. In a project lasting around six months you would not really expect to have more than three releases. Figure 6.5 adapted from Ould, 1999 illustrates the incremental model – in this case there are three incremental releases for the system. Notice that the requirements for the system are gathered in the usual way at the start of this process. You then design and prepare the first release of the system. This includes a kernel for your program and the first component of functionality that will be useful to the client. The second phase of the process involves designing the second increment of the system and developing and implementing this within the existing system. This process continues until all the increments have been completed and the system is fully working. Figure 6.5 also highlights two other aspects of the incremental approach. The first point to note is that the design stages of the later increments are not as detailed as the design stage of the first incremental release. This is because the first increment ofParts
» Projects in Computing and Information Systems A Student's Guide 0273721313 Pearson 2009
» Introduction What are computing projects?
» Computing project types What are computing projects?
» Programming in computing projects
» Degree structures Degree requirements
» Degree requirements for projects
» Overview Your supervisor Stakeholders
» Clients and users Stakeholders
» Evaluators and testers Stakeholders
» Overview How this book is arranged
» Taught degree projects versus research degrees
» Summary Projects in Computing and Information Systems A Student's Guide 0273721313 Pearson 2009
» A definition What is research?
» Originality What is research?
» Gaincontribution What is research?
» Knowledge and understanding What is research?
» Identify the broad area of study.
» Plan how you will perform the research.
» Gather data and information.
» Analyse and interpret these data.
» Present the results and findings.
» Review the field – i.e., perform a literature survey.
» Build a theory – based on your understanding and interpretations of the field.
» Test the theory – does it work?
» Reflect and integrate – i.e., update your ideas based on your ‘tests’ and contribute
» Intellectual discovery The research process
» Research methods Research methods
» List or multiple choice. Provides the respondent with a number of options to
» Scale. Used to rate the respondent’s feelings towards something.
» Ranking. Used to order a series of options. You should not provide too many
» Complex grid or table. Used to gather similar responses on a range of questions.
» Open-ended. Used to obtain extended, qualitative answers.
» Summary Further reading Action points
» Techniques and Information Sources
» Additional considerations Choosing a project
» Follow any guidelines precisely. Most institutions require specific information; for
» Proofread thoroughly and get someone else to check it. Any errors or omissions
» Introduction to the subject area. This will provide the reader with an under-
» Current research in the field. This will emphasise that your project is not based in
» Identify a gap. You should be able to identify some aspect of the field that requires
» Identify how your work fills the gap. Having identified a gap in the field, your
» Identify risks and solutions. It is also useful in a project proposal to highlight any
» Explicit sections Preparing a project proposal
» Reviewing your proposal Preparing a project proposal
» Exercise Projects in Computing and Information Systems A Student's Guide 0273721313 Pearson 2009
» The project process Introduction
» Definition The project’s stages
» Planning The project’s stages
» Initiation The project’s stages
» Control The project’s stages
» Closure. The project’s stages
» Complete a literature search and literature review of existing stock market prediction
» Develop a suitable artificial neural network model.
» Identify and collect suitable data for analyses and evaluation.
» Evaluate the model using appropriate statistical techniques.
» Complete final report. Setting objectives
» Step 1 – Work Breakdown Project planning
» Step 2 – Time estimates Project planning
» Step 3 – Identify milestones Project planning
» Step 4 – Activity sequencing Project planning
» Step 5 – Scheduling Project planning
» Step 6 – Re-planning Project planning
» Rolling wave planning Project planning
» Risks. Include a list of critical risk factors and means of dealing with these risks
» Organisation. If you are undertaking a group project it would be worthwhile
» Alleviate critical risks Introduction
» Identify risks Risk management
» Alleviate critical risks Risk management
» Controlling risks Risk management
» Research degrees versus taught degree projects
» A starting point Introduction
» The literature survey process
» Format of information Literature searching
» Tracing the information Literature searching
» Inter-library loans Literature searching
» Some tips for performing a literature search
» Critical evaluation Writing literature reviews
» Overview The past Introduction
» Introduction The software development life cycle SDLC
» Requirements definition Requirements capture
» Requirements specification Requirements capture
» Functional specification Requirements capture
» Design The software development life cycle SDLC
» Build The software development life cycle SDLC
» Test The software development life cycle SDLC
» Implementation The software development life cycle SDLC
» The earliest ’model’: build-and-fix
» The stage-wise and classical waterfall models conventional models
» explore the requirements of the system with the user – requirements capture, andor
» explore the technical feasibility of a system – experimental prototyping.
» Which development approach should I use?
» Which programming language should I use?
» Introduction Top-down and bottom-up development
» Top-down development Top-down and bottom-up development
» Bottom-up development Top-down and bottom-up development
» Verification Verification, validation and testing
» Validation Verification, validation and testing
» Testing Verification, validation and testing
» Who is involved with testing and evaluation?
» Test plans Miscellaneous testing types
» Quality assurance and quality control
» Exercises Projects in Computing and Information Systems A Student's Guide 0273721313 Pearson 2009
» Getting started – project initiation
» Managing the five project elements
» Introduction Dealing with problems
» Weakening Dealing with problems
» Personal problems Dealing with problems
» Hardware failure Dealing with problems
» Data availability Dealing with problems
» Discovering your workresearch has been done before
» Analyse what you are currently doing.
» Change what you are doing to achieve your aims.
» eliminate activities you don’t need to do; and
» be more efficient doing the things you have to do.
» Time management tips Procrastination
» Using your supervisor effectively
» Introduction Working in teams
» Team development Working in teams
» Managing the team Working in teams
» Teamwork tips Working in teams
» Considerations Writing and structuring reports
» Approaches to writing Writing and structuring reports
» When should I start writing?
» Identify structure. This relates to the content of your report, using a report break-
» Identify presentational style. You should also try to set standards at this stage on
» Draft the introduction. The introduction gives the reader an idea of the
» Develop the main body. The main body of your report is the next part you
» Articulate conclusions and make recommendations. Quite clearly, your conclu-
» Complete the introduction. As part of the evolutionary approach to writing,
» Write the abstract. You cannot really write a clear abstract for your report until
» Add references and appendices. Although you will be collating references and
» Arrange contents list, index. Leave the completion of an index if one is required
» Proofread, check and correct. It is vitally important to proofread your report after
» Introductionliterature review – the first chapter of your report should always be
» Main body – the content of which depends on the type of project you are un-
» Conclusionsrecommendations – summarises the contribution of the work and
» Style Writing and structuring reports
» Word processing Writing and structuring reports
» Tips Writing and structuring reports
» Presenting charts and graphs
» Common mistakes Data presentation
» Miscellaneous charts Data presentation
» Other data presentation Data presentation
» Introduction Referencing material and avoiding plagiarism
» Citing references Referencing material and avoiding plagiarism
» Listing references Referencing material and avoiding plagiarism
» Commenting program code Documenting software
» Writing user guides Documenting software
» The presentation content Visual aids
» Introduction. One or two slides that introduce you and your talk.
» Main body. The slides that constitute the bulk of your presentation and cover the
» Summaryconclusion. A few slides that summarise your presentation and perhaps
» Dealing with questions Oral presentations
» Poster preparation tips Poster presentations
» Introduction Preparation Demonstrating software
» Demonstration tips Demonstrating software
» Introduction Viva voce examinations
» Introduction Examiners and the marking of your project
» General. Examiners will look at the relevance and appropriateness of the topic
» Report. Examiners will look for clarity, consistency, an appropriate use of
» Defence. Examiners will assess the types of arguments you have made to support
» Other. Examiners will review the administrative issues of your project. For example,
» What was the research question?
» Is it a ‘good’ question? This involves a comprehensive literature review to ensure
» Has the student answered the question adequately?
» Has the student made an adequate contribution to knowledge?
» The project approach from a technical perspective i.e., not a project management
» General project considerations subject independent
» Literature reviewproject foundation Assessment criteria
» Project approachmethods Assessment criteria
» Results and contributions Assessment criteria
» Introduction Taking your project further
» Seeking funding Developing commercial software packages
» Copyright and patents Taking your project further
Show more