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Enabling Decision Support and Costing of Product Designs by using Visual Metaphors - HTML - HTML Version - Word - Word Adobe Acrobat PDF
The diagram below illustrates the aim of having a two way translation between all levels in a hierarchy of translation between human and computer, and between different software environments.
Figure 2 shows the translation mechanism.
Fig. 2. - Translation Process.
The approach involves adapting or creating software systems to provide the visual editor for the source tree, and model builders can create a model by editing this. By doing so they would create a generic model for a particular modelling subject. This is enabled by provision of translation software to translate the taxonomy into a decision support and modelling system. The model users can then use this decision support and modelling system to create their models. These models are a more specific subset of the generic model, and could be applied for their own analyses. Current research is on provision of a translation mechanism to convert information or models into other languages (primarily web based), and to visualise this information. This mechanism has been used in projects with two major aerospace companies. Examples of this are shown later in the paper.
Figure 3 shows the methodology behind the semantic web modelling. We have already prototyped all these stages, but have not yet developed a fully working modelling system to be used outside the university.
Fig. 3. Visualisation and Interaction Mechanism.
1. Connections are established between the ontology system and any databases, spreadsheets, or other systems that hold relevant information for that modelling problem.
2. The ontology is created using RDF/OWL [27], and an interface built to allow domain experts to edit the ontology.
3. Libraries are created in a partnership between ourselves and domain experts.
4. Taxonomies are populated by model builders who want to use them for their modelling problem. These are based on the libraries created in step 3.
5. Taxonomies are colour coded for ease of understanding, this part of the diagram was built with Vanguard system (explained below). We have created a link between the ontology tool and this decision support and calculation tool. Vanguard system reads information from the ontology tool.
6. There are 2 sorts of constraints that can be used in order to make it easier for users to build and adapt models. These are constraints on the way the ontology, and models are built, and user interface constraints to reduce the scope for error.
7. The colour coding makes calculation clearer because all taxonomies can be used in any calculation, this results in a multicoloured result tree that represents the entire calculation history. User choices affect how items are related for the calculation; choices could be made manually or via a search. Colour can also be used to represent cost, time, or uncertainty.
8. Each node can also represent uncertainty, and we have prototyped including uncertainty expressions in the calculations.
9. The result tree can be represented on the web and in other programs, this allows for further searching, processing and evaluation of results. Visualisation techniques and the use of searchable languages such as XML, and SVG can assist in this.
10. and 11. Experts such as designers can interact with the ontology, the model, and results, it's intended that there will be a two way feedback mechanism where the expert can make changes at any stage, and this filter into changed results. This can then support a cycle of results and rework.
The component is created, Input Values are defined and these can be used in a calculation. First the length of the rectangle is defined. This is given a value of 4 metres. Next the width of the rectangle is defined. This is given a value of 2 metres. Another class is created for the results of calculations. This is called Derived Values, but could be given any name. In this example there is just one derived attribute - Area. Area is assigned a value of Length * Width. This is a simple equation that will be used to calculate the result. Calculations are all defined by equations that relate attributes of the taxonomy. Figure 4 shows this.
Fig.4. Rectangle Explanation - Protégé.
The taxonomy is translated and stored in a relational database that maps the structure. The taxonomy can be read from the database by the decision support system DecisionPro. Generic code written using the DecisionPro editor reads from this database and recreates the tree. This represents the task of the software developer in providing the infrastructure for the users/model developers. The advantage of translating the taxonomy into a decision support system is its facility for performing calculations and statistical analysis. This allows the calculation to be made and visualised without any need for the user to create code. The calculation uses the equation(s) defined in the Protégé editor, which relate the nodes in the taxonomy tree. Figure 5 shows this.
Fig.5. - Rectangle Explanation - DecisionPro
The result tree can then be output onto the Web, in W3C compliant languages.
XML (eXtensible Markup Language) and stylesheets are used to display this output in the browser, but any language or format could be provided for. The tree is then displayed in a browser, and it's possible to click on individual items to view the item, and details such as the equation and result. Figure 6 illustrates this.
Fig.6. Rectangle Explanation - Web View Tree.
Sometimes an alternative is needed to the tree view of a taxonomy such as a diagrammatic representation of the object. The alternative view is created using an automated transformation that converts the tree into an interactive diagram. This alternative can be displayed on the Web page using SVG (Scalable Vector graphics). SVG is an XML format. Interactivity is added to help visualisation, and allow for inputs to be changed dynamically.
Figure 7 shows an output SVG rectangle diagram that includes interactivity. This has been translated from the tree-based representation. The input values used for the calculation and the diagram itself can be changed via an automatically produced user interface that is related to the taxonomy structure.
Fig.7. Rectangle Explanation - SVG Diagram View.
The area and the shape of the diagram respond dynamically to any changes in the inputs such as holding down the up or down arrows to change the input values, and there are other controls for moving and resizing the diagram.
A flash movie illustrating this example is available at http://www.cems.uwe.ac.uk/~phale/RectangleDemo/RectangleDemo.viewlet/RectangleDemo_launcher.html.
The example used to illustrate the new approach uses information taken from the composite wing box spreadsheet.
The implementation creates decision support programs automatically in response to user choices. The translation then creates programs in other computer languages, which allow presentation of results. The basis of this is that elaborators are nodes in the tree, which are automatically created and dynamically write objects. This allows our wing box definition to be translated to the decision support system for costing, and then to other software such as web pages for further processing or visualisation. Taxonomies are created in Protégé for Parts, Materials, Consumables, Processes, Rates, and Tooling for a prototype costing system. New categories can be produced as required. Domain experts would edit the taxonomies; these experts can specify the relationships of classes and the equations to be used via a visual user interface in Protégé. These relationships are evaluated and translated to produce computer code. Figure 8 illustrates how code is produced from the semantic relationships.
Fig.8. Rectangle Explanation - SVG Diagram View.
Figure 9 shows the equation as text in the Documentation field of the Periphery attribute of Derived Values. This equation text is translated into the DecisionPro visualisation.
Fig.9. Spar Periphery Calculation translated from Protégé.
For the prototype to be extended and applied for external use each taxonomy would be filled with a structured tree representation of experts' knowledge in the form of classes, values and equations. A costing tree can be produced automatically from these taxonomies. Equations created by the expert, together with choices made by the user of the decision support software, determine how these taxonomies are linked for a particular costing. The costing tool user would then determine which costing equations are used, by answering questions on dialogue forms. These questions would be asked whenever multiple solutions were available. The benefit of this approach is that the user interface and calculations will be changed automatically to reflect any changes in the model. So if the problem to be modelled changes, only the information that defines the model needs updating, and not the user interface or calculation engine. Figure 10 shows the top level of the user interface created automatically by our DecisionPro software from the Protégé taxonomies.
Fig.10. Interface automatically generated from Protégé.
The user will make choices so the decision support result tree will be a subset of the information source tree.
DecisionPro visualises large trees by breaking them into individual pages, and indicating with a right arrow where there are further pages that can be viewed. Clicking the 'Part Definition' right arrow will display the corresponding information. The 'Derived Values' branch contains parameters of the spar that are calculated from the spar dimensions. Figure 11 illustrates this.
Fig.11. Interface automatically generated from Protégé - spar definition.
Figure 12 shows the DecisionPro tree translated into XML and displayed as a web tree using a stylesheet. The menu uses a stylesheet created by De Andreis [56].
Fig.12. XML web translation from Decision tree.
The production of part diagrams using SVG can be automated in a similar manner to that used for the automated production of DecisionPro costing models. Figure 13 shows an example of such an interactive visualisation of a Spar. This interactive diagram was automatically translated from the part definition described in the part taxonomy.
Fig.13. Interactive Spar Diagram (SVG).
Interactive SVG Examples - Interactive SVG Examples - Wing Components.
The way the user can interact with the diagram can be seen by viewing these examples on our Interactive SVG links page demonstrated in [52].
The XML can also be displayed on the web using a Flash program created by Rhodes et al. [53]. This creates a tree with a three dimensional look and a use of colour, shading, and movement of the nodes that makes it an intuitive user interface that is easy to navigate. When a node is chosen, this is moved to the centre of the display and all the other nodes are moved or rotated to position themselves in relation to it. This interface is illustrated in Figure 14.
Fig.14. Flash interface for navigating exported XML tree.
Interactive SVG Examples - Interactive Flash Example - Wing Components.
The representation can also be translated into Java, and cost Estimator
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