2006-01-3493

Physical to Functional Mapping with Mindmap Software

Michael R Sevcovic International Truck and Engine Corporation

Copyright © 2006 SAE International

ABSTRACT

This paper describes how mind mapping software can help to visualize:

• System performance requirements

• Product attributes that satisfy performance requirements

• Mapping between performance requirements and product attributes

An example is given using a partial model for vehicle performance developed by the International Truck and Engine Corporation. The mind map software used in this study is Mind Manager Pro version 6 by Mindjet. Anecdotal evidence is offered for the benefits and challenges of implementing a visual Mind Map scheme; however, the judgment of overall effectiveness is left to the reader.

INTRODUCTION

THE NEED

There is little doubt in the systems engineering community that visual images convey information more succinctly and quickly than text; however, it is generally challenging to determine how far to go with images. Visual images tend to be more difficult to create and maintain than text or tables, and sorting or filtering can be more difficult with strictly visual content. Modern systems engineering tools such as IBM/Rational Rose, Telelogic DOORS/Tau/Rhapsody, UGS TeamCenter Requirements a.k.a. SLATE and Artisan Real Time Studio provide a feature-rich environment for visual modeling and mapping the models to text-based requirements. One of the shortcomings of all of the aforementioned tools is that they require a steep learning curve and constant usage for developers to remain effective in their use. A need exists for a simple tool and method that provides adequate visual modeling capabilities at a lower deployment cost than full-featured tools. It is the intent of this paper to provide the reader with one possible way to deploy mind maps in a Systems Engineering application, and to allow readers to decide if it might work for their organization. If the readers wish to become more familiar with mind maps, it might be useful to refer to Appendix 1 which is a mind map of this paper.

THE EXAMPLE

The example map for this paper is based on Class 6 – 7 commercial vehicles produced by the International Truck and Engine Corporation, and is shown in Appendix 2 – 8. In order to simplify the graphics for this paper, the example shows a partial list of Vehicle Performance Targets and a Product Entity Structure (Physical Architecture). If an element in the vehicle affects a Vehicle Performance Target, a curved arrow is shown from the Performance target to a measurable attribute of the physical subsystem. This example focuses on the Vehicle Performance Targets of Subjective Handling, Subjective Ride, Steering Wheel Vibration and Pass-by Noise and shows how the physical systems/subsystems impact the performance targets. It also shows how one might map customer needs to system performance targets using mind map relationships. Since the example has a large amount of graphic content that is cumbersome to distribute in a word processor format, a web site has been established (www.systemsarts.com/5.html) to allow the reader to explore the details in color and with better visual resolution.

THE BENEFITS, LIMITATIONS AND POSSIBILITIES

For systems of relatively low complexity, the mind map representation may help developers conceptualize the relationships between the parts they are designing and the performance of the system they are developing. The mind map software in this study proved to be easy to use. One can become productive with the software after one or two days use. Depending on a development team’s propensity for learning new tools, this ease of use is a key benefit. It is this author’s opinion that the mind map approach becomes too cumbersome when the total number of objects exceeds 500. A quick look at the overview map (Appendix 2) will illustrate how the visual view can get quite complex. The filtering and view manipulation features of mind map tools such as MindManager help to manage the complexity; however, each user will discover his own pain threshold for graphic manipulation. Integrating mind maps with software applications such as Microsoft Office provides an opportunity to use mind

maps in a standard development environment. For example, MindManager exports to Microsoft Word, and maintains data linkages to Microsoft Excel and Project. This helps keep data synchronized between the mind maps and other documentation. The shape of mind maps lends itself nicely to P-Diagrams that are sometimes used in Failure Mode and Effects Analysis (FMEA).

MAIN SECTION

VEHICLE EXAMPLES

A website has been created (www.systemsarts.com) to aid in viewing the graphic content of this study. An overview page showing the graphic content of this paper is available on the website under Projects | Physical To Functional or by clicking http://www.systemsarts.com/5.html. Links to the individual graphic elements are included in the appendix. The overview mind map (Appendix 2) is barely legible due to the page size; however, it illustrates the overall flow of the mappings from the Vehicle Performance Targets on the left to Product Entity Requirements on the right. A more clearly viewable form of the overview map can be seen on the SystemsArts website. The native MindManager file is available on the SystemsArts website. This author strongly recommends that the reader download the trial version of MindManager Pro 6.0 or the free viewer from Mindjet in order to manipulate the mind map in its native form. MindManager creates .html output from a mind map, allowing for web based distribution of the mind map content. The web output has limitations that are discussed later in this paper; however, for the most part the web content is easy to create and quite useful. The .html output for the mind map in this paper is available on the SystemsArts website: http://www.systemsarts.com/SysartsContent/FunctionalPhysicalMindMap/MindJet/index.html . The reader may want to spend a few minutes exploring this view. The left side provides a site map. The graphic images are clickable and change as one navigates through the site map. The “Table Of Contents” and “Overview Map” links in the upper right hand corner of the page are quite useful, and the Overview Map graphics are clickable. A flat file table view of the data used to create this mind map study is available in: http://www.systemsarts.com/SysartsContent/FunctionalPhysicalMindMap/SAEPaper/CascadeGeneralStructure.htm Ride Quality View Example

In order to illustrate how to reduce the visual clutter by manipulating views in the Mind Map, Appendix 3 shows only the linkages between the Ride Quality Vehicle Performance Target and measurable physical subsystem attributes that impact Ride Quality. Note that some value may be obtained by simply relating

performance targets to physical systems or subsystems; however, it is this author’s opinion that relating measurable performance targets to measurable physical attributes gives developers the best guidance when designing subsystems. Another view of the same content may be obtained by looking at the web page output for the Ride Quality target. Appendix 4 shows an approximate view of the web page, which is better viewed on the website. Notice that the web page in Appendix 4 provides a nice Requirements Traceability list, showing the mapping from the system performance target to the physical subsystem requirements. Unfortunately, the MindManager web output does not show the linkage when viewed from the other direction, the physical subsystem requirements. As shown in Appendix 5, the traceability back up to Subjective Ride Quality does not appear in the web view. For example, it would be desirable that when one viewed the web output for item 2.6.2.8, Frame Vertical Stiffness, there would be a linkage back to indicate that this impacted the Subjective Ride Quality. In order to see this data, a filtered view must be created showing the frame attributes and the Vehicle Performance Targets they impact. Such a view is shown in Appendix 6. Exterior Noise Example

An additional filtered view showing the Physical Requirements that impact Exterior Pass-By Noise is shown in Appendix 7. This view shows interactions with different areas of the vehicle than those related to Ride Quality. Customer Needs Example

Brainstorming Customer Needs is an ideal application for mind mapping. A filtered view showing how a few Customer Needs map to Vehicle Performance Targets is shown in Appendix 8. Capturing Customer Needs and mapping them to system performance parameters is similar to Physical to Functional Mapping. SOFTWARE USAGE TIPS

If the reader is interested in using MindManager software, here are a few tips:

• Branches can be turned off and on by clicking the branch nodes shown as small circle with a “-“ or “=” inside. This allows views to be filtered down to a more manageable and printable size.

• Move objects around in the structure to provide better static “filtered” views. The relationships move with the object, so once the arrows are drawn, they follow the source and destinations objects regardless of where they are moved in the structure. One might consider adding a branch for viewing only in order to separate objects and create better static views. The

objects can easily be move back to their proper place in the structure after viewing is complete.

BENEFITS

The key benefit for using mind map software instead of full feature development tools (or no tools at all) is that one can generally create graphically rich views with a simple-to-use interface. It is safe to say that one can become proficient with mind map software within a few days of use, while full featured systems development tools generally require specialized training and months of use before one feels comfortable and productive. A mind map may be useful for initial analysis in cases where development with full featured tools is still desired. If someone is new to systems engineering tools and wishes to capture concepts quickly and share them with a wide audience, mind maps are a good choice. MindManager Pro software has the following specific benefits in the business environment.

• MindManager has been quite stable and robust throughout this study.

• MindManager integrates with Microsoft Office products such as Word (export), Excel (Import, data synchronization) and Project (Import, Export, data synchronization). An interface to Microsoft SQL is advertised; however, it was not tested for this paper.

• Mind Manager includes Global Search features that work in the native software.

• The web page export of Mind Manager is full-featured and easy to use.

• Mind Manager provides a free viewer application so one can view native MindManager files without purchasing the software.

When compared to traditional business applications such as word processors or spreadsheets, documenting relationships such as physical to functional mapping are more intuitive for visually oriented users.

LIMITATIONS

Complex Systems With Formal Traceability Needs

In the author’s opinion, a key limitation of mind map software is in areas where formal requirements tracability documentation is desired or required by a regulatory authority. The visual representation is good for concept development but not for formal reports, particularly when thousands of data items exist. An anecdotal rule of thumb would be to consider mind maps in situations where 500 objects or less need to be related. The MindManager software can handle many more objects; however, a process would need to be developed to handle partitioning the content across many maps. This is certainly achievable, but starts to blur the line between “simple and easy-to-use” and “full-featured, full scale development. Obviously maps with hundreds or thousands of objects become unwieldy to maintain and

difficult to print. It also becomes difficult to find and navigate to items as the complexity increases, and one becomes more reliant on the search tool to locate items. Web Output Limitations

While developing this paper, the author discovered a limitation in the way web output captures the relationship links from the mind map. Appendix 5 shows a scenario where an object on the tail end of a relationship line has the destination (head of arrow) objects listed in its web output, but the destination objects do not show the source (tail) objects in their web view. The author has contacted Mindjet to see if there is a way around this limitation, but there is no work around other than to create a second set of links. Mind Manager might be effective for formal requirements traceability if this limitation is removed. Functional Block Diagrams

One unique characteristic of mind maps is that they all have a “center” object from which all other branches radiate. While this makes the maps easy to understand and create, it poses a serious limitation if one wishes to create a functional block diagram or data flow diagram with a mind map. POSSIBILITIES

Here are a few ideas that are not directly related to the topic of this paper, but may be of interest to the reader: Spreadsheet and Database Connectivity

Mind maps are valuable for showing relationships, but it is not obvious how they might be used to quantify relationships and requirements values. For example, the vehicle performance targets of ride and handling tend to drive the mechanical design parameters in opposite directions. How might one capture this on a mind map? MindManager allows relationship links to be annotated with a “Callout Topic” and allows notes and attachments to be associated with map objects; however, these simple text based techniques are cumbersome for numerical analysis. It may be worth pursuing a way that mind map entities can be associated with database or spreadsheet items in order to overcome the limitations with numerical analysis. MindManager advertises interfaces to Microsoft Excel and SQL. P-Diagrams

P-Diagrams, which show a system and its input, outputs, noise and control factors have a shape that is ideally suited for mind map creation. These diagrams are used at the beginning of Failure Mode and Effects Analysis. A sample P-Diagram created with MindManager is shown in Appendix 9. The ease of creating such diagrams may justify the cost of the software with one drawing.

CONCLUSION

The following conclusions are suggested as a result of this study. The reader is encouraged to investigate further to determine if mind map software can improve their development process.

• Visual representation appeals to a wide range of readers, and helps de-mystify the physical to functional mapping aspect of Systems Engineering.

• Mind Maps are a good option for someone new to systems engineering tools that wishes to capture concepts quickly and share them with a wide audience.

• Mind Map requirements mapping techniques are useful for concept development on small to medium-sized systems with no formal traceability reporting needs. Full-featured requirements management tools may still be needed to capture detailed requirements.

• Filtering map views is necessary to narrow the focus to a specific performance attribute or product entity item. This is necessary to manage the visual complexity as the number of items on a map increases.

• Mind Mapping is useful for up front analysis identifying customer needs and mapping the needs to product performance targets.

• Software package limitation should be thoroughly understood before deployment.

• A web based interface is a key benefit for communicating to a wide audience and reducing document distribution costs.

REFERENCES

SYSTEMSARTS WEBSITE

www.systemsarts.com A website created by Mike Sevcovic to host the content for this paper and advance the art of Systems Engineering. MINDJET

www.mindjet.com Developer of the MindManager mind map software used in this study.

FULL FEATURED SYSTEMS ENGINEERING TOOLS

IBM/Rational

Rational Software Architect and Rational Software Modeler: http://www-128.ibm.com/developerworks/architecture/kits/?S_TACT=106AH01A&S_CMP=tbc_print Telelogic

DOORS Requirements Management and Tau Visual Modeling http://www.telelogic.com/corp/products/doors/index.cfm Rhapsody visual modeling and software development: http://www.ilogix.com/sublevel.aspx?id=53 UGS Team Center Requirements

Team Center Systems Engineering, Requirements (current version and replacement of Slate) http://www.ugs.com/products/teamcenter/sol_prod/systems_engineering/ Artisan Real Time Studio

Visual Modeling, Software Development: http://www.artisansw.com/ INTERNATIONAL TRUCK AND ENGINE CORPORATION

Manufacturer of commercial vehicles, diesel engines and school busses in North and South America. http://www.internationaldelivers.com/site_layout/index.asp

CONTACT

Michael R Sevcovic

International Truck and Engine Corporation

2911 Meyer Road

Fort Wayne, Indiana 46803

260-428-3358

Michael.sevcovic@nav-international.com

APPENDICIES

Appendix 1 - Mind Map of this Paper

For better viewing, go to: http://www.systemsarts.com/SysartsContent/FunctionalPhysicalMindMap/SAEPaper/PaperOutline.html

Appendix 2 - Overview Map

For better viewing, go to: http://www.systemsarts.com/SysartsContent/FunctionalPhysicalMindMap/MindJet/map.htm

Appendix 3 - Subjective Ride Quality Filtered View

For better viewing, go to: http://www.systemsarts.com/SysartsContent/FunctionalPhysicalMindMap/SAEPaper/FilteredRideQuality.html

Appendix 4 -Subjective Ride Quality Web View

For better viewing, go to: http://www.systemsarts.com/SysartsContent/FunctionalPhysicalMindMap/MindJet/SubjectiveRide.html

Appendix 5 - One Subjective Ride Quality Child View

For better viewing, go to: http://www.systemsarts.com/SysartsContent/FunctionalPhysicalMindMap/MindJet/FrameVerticalStiffness.html

Appendix 6 - Frame Impact on Vehicle Performance

For better viewing, go to: http://www.systemsarts.com/SysartsContent/FunctionalPhysicalMindMap/SAEPaper/FilteredFrameImpact.html

Appendix 7 - Exterior Pass By Noise Filtered View

For better viewing, go to: http://www.systemsarts.com/SysartsContent/FunctionalPhysicalMindMap/SAEPaper/FilteredPassByNoise.html

Appendix 8 - Customer Needs Filtered View

For better viewing, go to: http://www.systemsarts.com/SysartsContent/FunctionalPhysicalMindMap/SAEPaper/FilteredCustomerNeeds.html

Appendix 9 – Under Hood Thermal Management Sample P Diagram

For better viewing, go to: http://www.systemsarts.com/SysartsContent/FunctionalPhysicalMindMap/SAEPaper/UnderhoodThermalManagementP/map.htm