It aims at the interactive development of qualitative multi-attribute decision models and the evaluation of options. A multi-attribute model is a hierarchical structure that represents the decomposition of the decision problem into subproblems, which are smaller, less complex, and possibly easier to solve than the complete problem.
Availability
This is useful for supporting complex decision-making tasks where a particular option must be selected from a range of possible options in order to achieve the decision maker's goals.
Functionality
DEXi differs from most conventional multi-attribute decision modeling tools in that it uses qualitative (symbolic) attributes instead of quantitative (numeric) attributes. It also has better graphical and reporting capabilities and facilitates the use of weights to represent and evaluate qualitative utility functions.
Applications
On the other hand, DEXi is somewhat less robust than DEX in handling incomplete option descriptions: DEX uses probabilistic and ambiguous value distributions, while DEXi only facilitates the use of unambiguous or unknown option values.
Development and history
Versions
Credits
Acknowledgments
Decision Analysis
Decision Problem
Decision Process
Participants of the Decision Process
Stakeholders (also called decision problem owners): individuals or organizations who have a legitimate interest in the decision problem. Experts: People with knowledge in the field so that they can provide information and advice important to the decision.
Decision Problem Identification
They can contribute to the overall identification of the decision problem, to the definition of options, goals and criteria and to the development of the decision model. It is important that the decision problem can be decomposed into smaller, less complex sub-problems and that the options can be described by their basic features that correspond to the problem breakdown.
Decision Model
It should primarily be about options that need to be evaluated, analyzed and compared.
Multi-Attribute Model
Qualitative Multi-Attribute Model
Attribute
Tree of Attributes
Interpretation
Linked Attributes
Recommendations
Scale
Example scales
Recommendations
Utility Function
- Intervals
- Complex Rules
- Weights
- Combinatorial Explosion
In DEXi, a utility function maps all combinations of lower-level attribute values to values of Y. Consider a utility function f that maps attribute values X1, X2,.., Xn to the value of the aggregate attribute Y .
Options
Evaluation of Options
In all cases, you must regroup the lower-level attributes and introduce one or two new aggregated attributes, denoted by . In the evaluation, undefined values of base attributes, denoted by '*', are interpreted as sets of all possible values that can be assigned to corresponding attributes.
Analysis
DEXi Model
DEXi File
Main Toolbar
File Menu
Option Data File
Option data files contain option data that is imported and exported via File Menu commands. On the Chart page/Settings sub-page where you can select settings to actually export (all settings are selected by default). In 'Import options' and 'Export options' dialogs used to specify file names and basic file format, which is either 'tab separated' or 'comma separated (CSV)'.
Tab-separated settings data file containing both options from the car evaluation model and exported using the default settings: using 'base 1' values, displaying all attributes using indentation, normal orientation. The same data as above, but using comma-separated format, 'base 0' values, and with only non-indented base attributes in normal orientation.
Function Data File
Exported the same function using text values and exporting only entered lines (in this case there is no need to display the '+' or '-' entered status).
Edit Menu
Window Menu
Help Menu
Model Window
Model Page
- Workspace
- Commands
- Remarks
- Tree View
Add attribute: This command creates a new attribute and inserts it into the tree as a descendant ('child') of the currently selected attribute. Paste: Inserts the previously cut or copied sub-tree into the model, positioning it as a descendant ('child') of the currently selected attribute. Duplicate: Creates a copy of the currently selected sub-tree and inserts it as a new top-level tree in the model so it can be easily moved around.
Move Up: Moves the currently selected attribute up one position from where it is displayed in the tree view. Move Down: Moves the currently selected attribute down one position relative to what is displayed in the tree view. Criterion: Invokes the Criterion Editor to create or edit the criterion of the currently selected attribute.
Reverse scale: The scale of the currently selected attribute is reversed: all scale values are placed in reverse order, and the scale order is changed from descending to ascending or vice versa. Utility Function: Invoke the Function Editor to create or modify the utility function of the currently selected aggregate feature.
Scale Editor
Workspace
Aggregate property whose utility function cannot be constructed due to undefined scales of its own and/or its descendants. Sometimes and only with good reason, it is acceptable to leave a partially defined utility function and/or have a linked property.
Commands
Remarks
Function Editor
- Table
- Toolbars
- Pop-up Menu
- Utility Function Status
- Weight Editor
- Handling Non-Entered Function Values
- Function Editing
- Function Chart
By default, non-entered values are handled by DEXi and recalculated every time the table has changed. Use scale orders and Use weights are two checkboxes that define how to handle non-entered values. This is generally achievable with less than 100% imported rules due to DEXi's handling of non-imported values.
Rounding' specifies how to calculate the values of non-typed rules that lie equally between two ordinal values. In the Function Editor, values for auxiliary functions are either entered by the user or not entered. Untyped values are displayed in normal font and by default are recalculated when the table changes.
Similarly, a bad value entered for rule 7 means that the value of unentered rules 4 and 1 is also bad. Using these weights and the already defined rules 3, 5, 7, and 9, DEXi constructed a hyperplane and used it to determine the values of the unentered rules and 8.
Options Page
Workspace
Arrows, which appear in the control area, indicate the axis used to display the corresponding attribute. The graphical display can be changed from the controls in the lower right part of the window: Zoom, Rotation (horizontal), Height (vertical), Spacing (setting the labels of the ground axes) and Font size. Double-clicking the leftmost table header automatically adjusts the width of all columns in the table.
Commands
Remarks
Evaluation Page
Workspace
The workspace is similar to that of the options page in that it provides a table of information about the options. The difference is that all optional data is displayed here, including base and summary attribute values. The rows of the table correspond to all attributes and are displayed to show the tree structure of the current model.
When you select a cell that corresponds to a basic property, a data entry field appears on the toolbar, allowing you to change the value of that cell in the same way as on the settings page.
Commands
Plus-Minus-1 Analysis: Investigating the effects of changing the value of the underlying options by one step up and down.
Analysis Menu
Option analyses
Charts Page
Workspace
Commands
Show Values: When this item is checked, full-scale value names are displayed in graphs. Show option names: This item determines whether or not option names are displayed in charts.
Report
Report elements
Copy Chart: Copies the current chart to the clipboard so that it can be pasted into other documents. For each scale in your model, the scale name, associated attribute description, and all scale values are printed along with their own values. Only options selected on the Charts page are included in this report element.
Preview
Internal browser
Settings
Report Page
Reports in html: If checked, all reports are drawn up in html and displayed in a browser, without activating the standard preview. Use default system browser: When checked, html reports are displayed using the default system browser, ie external to DEXi.
Import/Export Page
Advanced Page
Disable model editing: specifies whether or not it is possible to edit the model on the DEXi Model tab. It is possible to open Function Editor to view utility functions, but saving changes is disabled. Disabling model editing is useful to prevent inadvertent changes after the model is completed.
This is a very small and simple model used to illustrate the main concepts of multi-attribute modeling and DEXi, and is not intended to solve the problem of car evaluation at any realistic level. This model has traditionally been supplied with all previous versions of the DEX and DEXi programs.
Tree of Attributes for Car Evaluation
Interpretation
Attribute Types
Attribute Descriptions
Scales for Car Evaluation
Utility Functions for Car Evaluation
Interpretation
Each row provides a value of CAR for one combination of the values of PRICE and TECH.CHAR.
Elementary decision rules
Complex rules and weights
Description and Evaluation of Cars
Interpretation
At the bottom, the table shows two options, Bil1 and Bil2, described by the qualitative values assigned to the six basic characteristics of the tree. These values were then aggregated from the bottom to the top of the tree of attributes according to the structure of the tree and defined auxiliary functions. In this way, intermediate evaluation results are obtained first and attributes PRICE, COMFORT and TECH.CHAR are assigned.
Some Car Option Analyses
Plus-minus-1 analysis
The two brackets ']' indicate that the values of corresponding attributes, #PERS and LUGGAGE, can no longer be incremented, thus preventing the +1 portion of the analysis.
Selective explanation
Compare options
Some Car Evaluation Charts
Bar Chart
Scatter Chart
Radar Chart
Documentation in Slovene
Publications
Bohanec, M., Messéan, A., Scatasta, S., Angevin, F., Griffiths, B., Krogh, P.H., Žnidaršič, M., Džeroski, S.: A qualitative multi-attribute model for economic and ecological assessment of genetically modified crops. Pavlovič, M., Čerenak, A., Pavlovič, V., Rozman, Č., Pažek, K., Bohanec, M.: Development of DEX-HOP multi-attribute decision model for preliminary assessment of hop hybrids. Mileva Boshkoska, B., Bohanec, M., Boškoski, P., Juričić, Đ.: Copula-based decision support system for quality ranking in electronically commutated motor manufacturing.
Bohanec, M., Trdin, N., Kontić, B.: A multi-criteria qualitative model for the evaluation of electricity generation technologies in Slovenia. Trdin, N., Bohanec, M.: Extending the DEX multi-criteria decision-making method with numerical attributes, value distributions and relational models. Nusev, G., Boškoski, P., Bohanec, M., Mileva Boshkoska, B.: A DSS model for module computer selection based on PROMETHEE and DEX methods.
Delibašić, B., Radovanović, S., Jovanović, M., Bohanec, M., Suknović, M.: Integrering af viden fra DEX-hierarkier i en logistisk regressionsstablingsmodel til forudsigelse af skiskader. Žnidaršič, M., Ženko, B., Osojnik, A., Bohanec, M., Panov, P., Burger, H., Matjačić, Z., Debeljak, M.: Multi-criteria modeling approach for ambient assisted coaching of senior voksne.
Version 2.0
New components
New program features
Changed program features
Bug fixes
Version 3.0
- New program features
- Changed program features
- Changed documentation
- Bug fixes
Improved option data entry: right-click menus are now also available on the Options and Evaluation Pages. Added Collapse/Expand commands to change the display of feature trees on the Model page.
Version 3.01
New program features
Bug fixes
Version 3.02
New program features
Version 3.03
New program features
Bug fixes
Version 3.04
New program features
Bug fixes
Version 4.00
Technical issues
New program features
Version 4.01
Technical issues
New program features
Bug fixes
Version 5.00
Licensing
Technical issues
New program features
Bug fixes
Version 5.01
Bug fixes
Version 5.02
New program features
Version 5.03
Technical issues
New program features
Bug fixes
Version 5.04
New program features
