Exploring SysML with David Hatharington at EA Global Summit 2021

Welcome to the EA Global Summit 2021, organized by the summit team member Sujath. David Hatharington, head of research and development with over 10 years of managerial and consulting experience, 15 years in modeling safety critical systems and enterprise architecture, and over 20 years in software and system architecture, will be presenting on Sis ML Quick Start using Enterprise Architect.

Participants will be muted throughout the session. Questions can be asked via the chat window, and queries will be addressed at the end of the session. Participants are encouraged to visit the Microsoft Teams channel post-session for further discussions with David and other EA practitioners.

Participants facing difficulties in connecting to Teams can contact the organizers via the chat window or email at registration@globaleaglobalsummit.com. The session aims to provide valuable insights and support to all attendees.

David is invited to start his presentation, setting the stage for an informative session. The audience eagerly awaits the valuable insights and knowledge he will share.

David greets the audience, mentioning his location in Austin, Texas, and the session's focus on using Enterprise Architect for Sis ML. He plans to demonstrate model construction and provide detailed guidance. The presentation slides and additional resources are available for download on the Teams channel.

SysML is a system modeling language developed by INCOSE and OMG, serving as a standard for system modeling. It is not a mere PowerPoint compiler but a comprehensive language for modeling complex systems. Interested individuals can access tutorials and resources on SysML for beginners on the ASATE Press website.

Discussion on the ethical implications of cloud applications, including data privacy laws, driving data visibility, and decision-making scenarios like speeding near schools.

The purpose of SysML is to establish a common understanding among stakeholders without replacing their specialized tools, such as CAD systems for mechanical engineers, accounting tools for accountants, and databases for lawyers.

Overview of Enterprise Architect 15.2 with a focus on the SysML perspective, emphasizing the importance of setting perspectives for effective modeling.

Guidance on creating a doorbell system model in Enterprise Architect, starting with organizing elements into packages to enhance model clarity and ease of understanding.

The speaker introduced the concept of a block definition diagram, clarifying that it is not the same as traditional block diagrams used in hardware engineering. Instead, it functions more like a bill of materials diagram, illustrating the relationship between different types of components within a system.

A context diagram, such as the 'doorbell system context' mentioned, is one of the initial diagrams created to provide an overview of a system without delving into intricate details. It typically outlines the system and its top-level subsystems, as well as external entities related to the system.

In SysML, a block can represent various entities, ranging from hardware components to software systems or even abstract concepts like political parties or cooking recipes. This flexibility allows for a versatile modeling approach that is not limited to specific design types.

The speaker discussed the concept of part association in SysML, emphasizing that it signifies a structural relationship between components rather than a nesting of objects within objects. It functions more like a mounting bracket for parts, as seen in the example of a car's engine and mounting holes.

The diagram illustrates the basic structure of the doorbell system, consisting of a doorbell button unit and a chime unit. These components need to be assembled to create the complete system.

An 'actor' named the 'visitor' is introduced in the context of the doorbell system. The visitor is not a part of the system but interacts with it. To organize actors better, a new package called 'actors' is created, and the visitor is placed within it.

The diagram showcases the front doorbell unit and the kitchen chime unit as parts of the doorbell system. This setup forms the foundation for creating a bill of materials for the system.

A new package named 'requirements' is added to outline the system requirements. Specific requirements include a chime tone, a chime cycle of three rings, and a visual indicator on the doorbell button to confirm activation.

When setting up requirements, it is important to use short names for easy management. The process involves assigning a short name, such as 'chime tone,' and linking it to a number and text in the tool.

In the tool, requirement details like numbers and text have been moved to the 'Tags' tab. Users need to access the compartments and turn on tags visibility to view and input these details accurately.

Users can add requirements by creating a new entry with a title, such as 'final dim glow,' and linking it to a specific ID and text. This process allows for the systematic inclusion of multiple requirements in the tool.

Diagrams play a crucial role in understanding the usefulness of system modeling. By creating diagrams like 'idle dim glow details,' users can visually represent components like the doorbell button unit and establish requirements traceability.

Requirements traceability is essential for demonstrating how components, like the doorbell button unit, satisfy specific requirements. In complex systems, diagrams help illustrate the relationships between components and requirements, aiding in safety critical systems and regulatory compliance.

In SysML, verifying requirements is crucial. This involves creating relationships between different requirements, resolving conflicts, and depicting the final consensus requirement. Stakeholders need to be aligned on who needs to fulfill which requirement. This process is essential for validation engineers to understand what tests need to be conducted.

SysML includes three types of behavior diagrams: activity diagrams, state machine diagrams, and sequence diagrams. Sequence diagrams are particularly useful for illustrating how a system functions and can help stakeholders understand the system's operation. Creating a sequence diagram can show the flow of events when a visitor arrives, providing a clear visualization of the system's behavior.

Organizing a SysML model structure depends on what works best for specific stakeholders. There are various approaches like organizing by project phases, subsystems, or logical versus physical design. The key is to make the structure easy to understand for stakeholders. Flexibility in structuring the model is essential, and the organization should be tailored to the needs of the project.

In SysML, creating interactions involves adding an interaction element before creating a diagram within it. This process aligns with the standard requirements and ensures proper modeling practices. Following the correct procedure for creating interactions helps maintain consistency and clarity in the SysML model.

A visitor walks up and presses the button, initiating a message flow from the button to the chime unit. The message is named 'button pressed' to indicate the action taken by the visitor.

Initially, the message transmission was synchronous, symbolized by a solid triangular arrow, requiring the visitor to hold the button until someone responded. To make it asynchronous, the arrowhead is changed to an open one, allowing the visitor to release the button like dropping a letter in a mailbox.

Upon receiving the signal that the button was pressed, the chime unit instructs the button unit to start flashing asynchronously, indicating a response to the visitor's action.

The button continues to flash, signaling an ongoing response, while the chime unit eventually finishes its task, completing the interaction cycle.

In the final stage, the button transitions to a dim glow state, indicating the completion of the interaction process between the visitor, button, and chime unit.

Sequence diagrams are valuable for setting up test sequences and aligning stakeholders but can become complex if detailed loops are added. Balancing detail for compilation and stakeholder understanding is crucial.

Sequence diagrams, activity diagrams, flowcharts, and state machines can work together in system design to describe interactions and state transitions. They are especially useful for coordinating multiple independent components in a system of systems.

The quick start tutorial concludes, emphasizing the importance of diagram integration in system design. The tutorial provides a comprehensive overview of sequence diagrams and their role in system testing and stakeholder alignment.

David mentions that there is plenty of time for questions and offers to demonstrate tools. He encourages participants to ask questions and thanks David for the session.

The session transitions to the Q&A segment where questions from the chat will be read out and answered by David. Participants are encouraged to ask questions.

David highlights the availability of the tutorial for SML, mentioning the need for the corporate version of Enterprise Architect. The tutorial can be downloaded from asatepress.com, and the book on SSML is available in Kindle and paperback formats.

David invites participants to ask questions and mentions the availability of the presentation for download. He encourages attendees to send questions via chat and offers to stay for a while to address any queries.

A participant named Long requests David to show the CSML tutorial slide again, which David promptly displays.

Motiza asks about the differences between CSML and UML. David explains that CSML is built on UML but offers stereotypes more suited for a wider range of engineering applications. CSML simplifies diagrams, introduces new elements like parametric diagrams, and is geared towards designing complex systems beyond just software.

David elaborates on the industries and sectors that use SSML, including aircraft, defense, automotive, medical devices, trains, construction companies, and ships. He emphasizes that SSML is crucial for extremely complex and safety-critical systems where thorough documentation and testing are essential.

UML is used by software engineers, while SysML involves a variety of people beyond software engineers. SysML diagrams are not just for software engineers.

Rocky asked about importing requirements from Excel using EA Ultimate, but the demonstration was not possible during the session. EA Ultimate offers features to interface with Microsoft Office, export diagrams to PowerPoint, create Word documents, and exchange data with spreadsheets.

Long inquired about coding tests to simulate functions like flashing when a button is depressed. In reality, the test case team would create their own models, possibly modular, linked to a core model. SysML allows for generating code and documents, such as test plans.

David thanked the audience for their time and support during the session, offering to continue discussions in MS Teams. The link to the MS Teams channel was provided for further interaction. Any difficulties in connecting were to be addressed through the chat window or email at registration@daglobalsummit.com.