What is this?

xtUML Days 2020 UK is a modeling conference and represents the 7th edition of xtUML Days. (See Previous xtUML Days.) xtUML Days is the most dense gathering of Shlaer-Mellor modelers of the year. The xtUML Community meets to collaborate on Modeling, Method and Tooling.

The central topic of the conference is end-to-end modeling, execution, translation and deployment of models-as-code in mission critical settings employing rigorous methodology. The unifying theme is practical, actual, industrial application modeling within production installations. Attendees will network with engineers, scientists and educators who understand executable and translatable modeling as applied in active systems.

In 2020, a special focus will be continued to extend and clarify the Shlaer-Mellor Method in light of undocumented developments over the last several years.

Also in focus:

  • Method advances (specifically convergence of PT and K-C dialects)

  • Tooling Refinements

The xtUML Community is keen to exchange expertise and learn from one another. xtUML Days provides a forum for developers to share best practices and influence the direction of the technology. xtUML Days hereby solicits compelling papers and presentations that exhibit method advances, tooling improvements and application experience in Shlaer-Mellor modeling and related Executable/Translatable modeling. This year attendees represent One Fact, UK Crown, BAE Systems, ROGO, Northrop Grumman, Aurora Consulting, Software Improvements, L3, Thales, Toyo Corporation, ICS, FrogOOA, Kyushu University, University of Southampton and Jönköping University.

COVID-19 (Novel Coronavirus) Considerations

This conference may look totally different from previous years. Know your conference committee response will be marked by flexibility and creativity. We are hoping that the world will be normal enough in November to meet in the traditional fashion.

However, we are planning in case it cannot. There is the potential of slipping the date into 2021, but there is also the possibility of a virtual gathering. Your planning committee is super creative and has access to super techy people who know how to make virtual reality a reality. Do not think long, boring, online slideshows. We already have ideas for virtual happy hours and virtual tours and virtual panel discussions. Such approaches take a great deal of preparation which we are willing and even now proceeding to explore.

Keynote Speaker

Stephen Mellor

We are pleased to announce that the xtUML Days 2020 Portsmouth keynote speaker is Stephen J. Mellor, co-author of the Shlaer–Mellor Method and Executable UML, and signatory to the Agile Manifesto. Mellor has been working with methods, particularly executable methods, for real-time and embedded systems for four decades.

He explains, with clarity and humor, the intricacies of real-time and embedded systems model-driven development, in both presentations and text. He is the author of several books:

Stephen presently serves as Chief Technology Officer of the industrial internet CONSORTIUM (IIC).



xtUML Days 2020 UK will be hosted at The Queens Hotel Portsmouth in Southsea, Portsmouth, UK. The hotel combines luxury and history with an ideal location situated with walking access to the shoreline, parks, restaurants and to Old Portsmouth.


Register by emailing the chair (cortland.starrett at onefact.net). Provide name and company information. Do this even if you pay through the electronic portal below.

Registration is $500 (USD) for participants not under contract with the Community Engagement option. Payment can be made with a credit card (through a PayPal portal below). Payment can be made by check. Other methods of payment can be arranged through the conference organizers. Discounts are offered to companies sending more than 3 participants; contact the chair.

Agenda of Presentations

Thursday 5 November (Conference Day)


Travel and Reception Dinner

Plan to arrive Wednesday evening before the conference to attend a reception dinner (included in the conference registration while space permits). Dinner will be hosted at The Still and West. A private upstairs space is reserved for xtUML Days guests. Drinks and meeting and mixing will precede (and succeed) dinner. This is a lovely pub with a view of the Harbour. (The photo at the top of the page was taken from inside The Still and West.)


Portsmouth has many hotels and Airbnb options. The xtUML Days organizers will arrange for a block of hotel rooms with a group rate at the conference venue (The Queens Hotel Portsmouth). Please check back for details!

Call for Papers

A program committee will review and select from submitted papers, posters and presentations. Selection is based upon perceived value to the xtUML Community.

Topics of interest to xtUML Days include but are not limited to the following:

  • real-world application modeling examples of installed systems

  • techniques of editing, verifying, translating, debugging and deploying models

  • methodology (Shlaer-Mellor) advances, extensions and refinements

  • static analysis of models and generated code

  • model-based model compilers

  • model integrity

  • action language dialects

  • target software architectures and translation onto those architectures

  • process integration of modeling and modeling tools

  • tooling supporting the Shlaer-Mellor Method

  • current state of the art editing, verification, translation, debugging

  • recent experience with tooling and BridgePoint in particular

  • techniques for educating modelers from young children to experienced professionals

  • tooling migration experience reports

Submit your paper, poster or presentation electronically as PDF via EasyChair. (If you are unable to submit through EasyChair, please contact the Conference Contact.) Presentations are expected to be 35-45 minutes in duration including time for questions and discussion.

All submissions will be evaluated by the program committee. Selection is based upon significance, clarity and alignment with the call and value to the attendees of xtUML Days 2020 UK. Submissions that promote discussion, advance the Method and generate interaction among xtUML Community members are most desired. For a presentation to be accepted, at least one of the authors must register for xtUML Days, present the material and participate in the conference.

Important Dates

  • Abstract submission deadline: 15 August 2020

  • Author notification: 30 September 2020 (but likely shortly after abstract is submitted)

  • Submission deadline for presentation-ready version: 22 October 2020

  • xtUML Days conference: 5 November 2020

Conference Format

Day 1 of xtUML Days is an information dense and interactive conference lasting one full day. The host will welcome attendees at the starting hour. The host will make significant introductions. Key xtUML Community members will give short updates on their applications and experiences. Presentations with Q&A and discussions will fill the morning and afternoon sessions. An open moderated discussion time will end the day.

A detailed agenda will be available in October upon solidification of the speaking agenda.

A day 2 of xtUML Days is a planning day for active members of the xtUML Community. Planning Day is focused on short and long term requirements of the Method and road map for tooling. Day 2 attendance is by invitation only.

Conference Organization

  • Cortland Starrett, Conference Chair, One Fact, USA, cortland.starrett [at] onefact.net

  • Dave Skinner, Program Committee Member, BAE Systems, UK

  • Dave Salt, Program Committee Member, UK Government, UK

  • Emily Carter, Conference Coordinator, Change Agent Studio LLC, USA

Conference Contact

If you have questions about xtUML Days 2020 UK, contact the Chair via email at: cortland.starrett [at] onefact.net or the Conference Coordinator via email at: emily.carter [at] onefact.net.