Friday, July 13, 2007

User Driven Modelling - Detailed Explanation - Part 2 - Research Approach

This research demonstrates how a taxonomy can be used as the information source, from which it is possible to automatically produce software. This technique is most suitable at present to modelling, visualisation, and searching for information. The article explains the technique of User Driven Model (UDM) Development that could be part of a wider approach of User Driven Programming (UDP). This approach involves the creation of a visual environment for software development, where modelling programs can be created without the requirement of the model developer to learn programming languages. The theory behind this approach is explained, and also the main practical work in creation of this system. The basis of this approach is modelling of the software to be produced in Ontology systems such as Jena http://www.hpl.hp.com/semweb/ and Protege http://protege.stanford.edu/. It also has the potential to be computer language and system independent as one representation could be translated into many computer languages or Meta languages (will explaine in other articles).

The research applies this User Driven technique to aerospace engineering but it should be applicable to any subject. The basis of the research is the need to provide better ways for people to specify what they require from computer software using techniques that they understand, instead of needing to take the intermediate steps of either learning a computer language(s) or explaining their requirements to a software expert. These intermediate steps are expensive in terms of time, cost, and level of misunderstanding. If users can communicate intentions directly to the computer, they can receive quick feedback, and be able to adapt their techniques in a quick and agile way in response to this feedback.

A modelling environment needs to be created by software developers in order to allow users/model builders/domain experts to create their own models. This modelling environment could be created using an open standard language such as XML (eXtensible Markup Language). As the high level translation though this would depend on tools developed using lower level languages, this is why tools such as Protege and DecisioPro http://www.vanguardsw.com/are used. Vanguard are creating a modelling network where universities can share decision support models over a network [Vanguard 2006]. This tool was used because it was selected during a project to evaluate, and then use software to solve costing problems. We are creating a modelling network that will link to that of Vanguard http://www.cems.uwe.ac.uk/amrc/seeds/models.htm.

Until recently XML has been used to represent information but languages such as Java, C++, and Visual Basic have been used for the actual code. Semantic languages such as XML could be used in future for software development as well as information representation, as they provide a higher level declarative view of the problem.

A requirement of this research is that open standard semantic languages are used to represent information, to be used both as input and output of the model. These languages are based on XML. These same open standard languages can be used for developing the program code of models. It is proposed that software and information represented by the software, be separated but represented in the same open standard searchable way. Software and the information it manipulates are just information that has different uses, there is no reason why software must be represented differently represented differently from other information. So XML can be used both as the information input and output by the application, and for the definition of the model itself. The model can read or write information it represents, and the information can read from or write to the model. This recursion makes 'meta-programming' possible. Meta programming is writing of programs by other programs. The purpose of this is to provide a cascading series of layers that translate a relatively easy to use visual representation of a problem to be modelled, into code that can be run by present day compilers and interpreters. This is to make it easier for computer literate non-programmers to specify instructions to a computer, without learning and writing code in computer languages. To achieve this, any layer of software or information must be able to read the code or the information represented in any other. Code and information are only separated out as a matter of design choice to aid human comprehension, they can be represented in the same way using the same kinds of open standard languages.

Dynamic software systems such as outlined by Huhns [1]. Huhns explained that current techniques are inadequate, and outlines a technique called Interaction-Oriented Software Development, concluding that there should be a direct association between users and software, so that they can create programs, in the same way as web pages are created today. Paternò [2] explains research that identifies abstraction levels for a software system. These levels are task and object model, abstract user interface, concrete user interface, and final user interface. Stages take development through to a user interface that consists of interaction objects. This approach can be used for automating the design of the user interface and the production of the underlying software. Paternò states that 'One fundamental challenge for the coming years is to develop environments that allow people without a particular background in programming to develop their own applications'. Paternò goes on to explain that 'Natural development implies that people should be able to work through familiar and immediately understandable representations that allow them to easily express relevant concepts'.

The methods used for this representation and translation will be explained in the rest of this document.

References
1 Huhns, M. (2001). Interaction-Oriented Software Development. International Journal of Software Engineering and Knowledge Engineering, 11: 259-279.

2 Paternò, F. (2005). Model-based tools for pervasive usability. Interacting with Computers, 17(3): 291-315.



My Home Page is www.cems.uwe.ac.uk/~phale/.

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