January 4, 2018

Most MBSE methodologies place emphasis on organizing the model correctly before actually modeling the system, but this task should not be approached too narrowly.  First, as we discussed in a previous blog, modeling should encompass both the system under development and the project structure, which includes both process and organization. Model organization should facilitate collaboration

December 19, 2017
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Introduction Axe in hand, I strode into the misty forest, looking for the perfect Christmas tree. As the slushy snow soaked into my shoes, I thought, “I should have modeled this first!” In any project as critical as decorating the house for Christmas, Model-Based Systems Engineering has a lot to offer the serious practitioner. In

October 17, 2017

Introduction In the first four parts of this series, we have focused on the SysML modeling part of the systems engineering effort. While general-purpose modeling serves many purposes, some parts of design and analysis are best done with more specialized tools. The ability to keep multiple models consistent is the objective of Model-Based Engineering (MBE)

September 29, 2017
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Introduction SysML models readily connect structure, behaviors, requirements, and analysis in a single model. We started to show behaviors back in Part 1 with a series of simple state machine behaviors. In this blog post, we show how SysML interaction elements and sequence diagrams can be used to model the message-based communication between different parts

September 19, 2017

Introduction In this third post, we build simple rail subsystems from the blocks and control points created before. We offer two examples, a single track with a siding and two parallel tracks with crossovers. These can, in turn, act as parts of larger systems. This post is the third in a series of blog posts

September 14, 2017
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Introduction We extend our best wishes for safety and a rapid recovery to all those affected by Hurricanes Harvey and Irma, but we have a responsibility as system engineers to do more. The impact of these catastrophic weather events can be reduced by intelligent preparation and Model-Based Systems Engineering (MBSE) offers a better way to

September 6, 2017

Introduction One advantage of SysML for general-purpose modeling is that it is an object-oriented modeling language. We take advantage of it here to build RCS control point models, composed of Switch, LightSignal and JBox (communications junction box) building blocks. We can think of our RCS as a network of control points connecting blocks of bi-directional

August 16, 2017

Introduction In many respects, railway control systems (RCS) can be thought of as a pre-digital progenitor of the Internet-of-Things, a distributed network of sensors, actuators and intelligent control that work together to respond to a variety of situations. While there are many different approaches to RCS, modern systems are increasingly based on Centralized Traffic Control

August 8, 2017
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Introduction Electronics is increasingly about networked products. Here, MBE becomes critical to electronic product development because it incorporates the network connection in the model from the very beginning, including very detailed, reusable specifications of function and requirements. A significant benefit of the object-oriented general-purpose SysML modeling language is that models can be merged easily in