Monday, October 22, 2007
Thursday, September 20, 2007
XML MetricsOver the past few meeting with Nick we have began the developed of a framework for measuring the complexity of XML projects. We have based our framework on the extensibility manifesto by Rick Jelliffe.
The extensibility manifesto provides a good overview of the problems that face developers, and hence would provide a good framework to base the application of XML governance.
Using the Jelliffe's outline of the issues behind the extensibility manifesto [Jelliffe2006] as a basis, the following key areas were found:
- Stakeholder requirements
- Fit for purpose
Other Rick issues todo:
- Focus and agility
- Be Methodical
- Business data requirements - from the business end
- External data constraints - extra constraints for the data from the business end
- Stakeholder data requirements = business data requirements + external data constraints
- System data requirements - from the developers end
The schema must comply with all business requirements and external data constraints.
- All requirements and constraints must be documented and agreed upon
- Traceability and accountability must be maintained on all requirements throughout the development lifecycle
- Stakeholders should be informed of the resource implications of their data requirements and data constraints
The schema must be fit to produce the necessary functionality required by the system.
Compliance with business requirements does not necessarily result in a system which is of benefit to the client and fit for their purposes.
A list of good practices that we can apply to the issues of XML governance.
- Schematron - specify the gap between requirements and the data model
- Usage schemas - determine how the structure is being used. Often the schema is not a proper representation of the usage of a schema is not properly
- Progressive validation
- complexity of the schema
- element and attribute count
- Mapping completeness ratio - in fields : out fields
- Mapping additions ratio - from : to
- Configuration items - xlink to other forms of documentation
- XML auditability - daily build
[Jelliffe2006] Jelliffe, Rick 2006, "XML Governance & Publishing", Open Publish 2006
Wednesday, August 22, 2007
The authors conducted a study of the requirements engineering process in 15 software projects form a diverse range of industries. They investigated the RE practices and process that were used in each team and through questionnaires and interviews, collected data directly from each project’s stakeholders. A very insightful journal will be quoting this a lot!
Friday, August 10, 2007
The article: Estimating software projects(2001).
This article addressed the issue of the inaccuracy of project cost estimations due to that fact that it is done in the initial stages of the software development process and therefore likely to be based on incorrect or incomplete software requirements. More specifically it details the causes of poor and inaccurate estimation as being a result of imprecise and drifting requirements, new software projects are nearly always different form the last, software practitioners don't collect enough information about past projects, estimates are forced to match the resources available and there is a general lack of acceptance that developing software is an expensive endeavor. It went on to suggest cost estimation techniques and their various success rates.
This article lead me to the following questions: Does this mean that the completed, correct and non-changing requirement document which is need to deliver a successful project is never available at the commencement of a project? And that IT managers have come to expect this and concentrate their effects on the inevitable add ons and complications? Perhaps this is the reason why there is much focus on a project's contract and accountability. Or perhaps I have become too pessimistic :-D
Monday, August 6, 2007
Pressman's thoughts on web-based development echo my experiences at Allette Systems. Network intensive corresponds to the need for interoperability amount different applications, content driven is the complexity associated with the various data transformations and continuously evolving can be associated the need for compliance to standards that existing web based applications are expected to adhere to.
- Research Directions in Requirements Engineering by Betty H.C. Cheng and Joanne M. Atlee
- Towards a Requirements-driven Workbench for Supporting Software Certification and Accreditation by Seok-Won Lee, Robin A. Gandhi and Siddharth
- Aspectual Support for Specifying Requirements in Software Product Lines by Harvey Siy, Prasanna Aryal, Victor Winter, Mansour Zand
- Specification of Non-functional Requirements for Contract Specification in
the NGOSS Framework for Quality Management and Product Evaluation by
Xiaoqing (Frank) Liu, Manooch Azmoodeh, Nektarios Georgalas
- Requirements development as a modeling activity by Sergey Diev
- Modularisation and Composition of Aspectual Requirements by Awais Rashid, Anna Moreira, Joao Ara0jo
- R. Pressman. Software Engineering: A Practitioner’s
Approach. Mc-Graw Hill, New York, NY, fifth edition,
2000. Chapter 29.