Introduction to Model Based

Systems Engineering (MBSE)

Energy Tech 2016

L. Mark Walker

(28 November 2016)

Topics

• What is a Model?

• Overview of Model Based Systems Engineering (MBSE)

• The Systems Modeling Language (SysML)

• Object Oriented SE Method (OOSEM)

• Personnel & Training

• Tools & Examples

• Conclusions/Recommendations

What is a Model & a Simulation?

• INCOSE SE Handbook (Fourth Edition):

• “The term “model’ has many definitions but generally refers

to an abstraction or representation of a system, entity,

phenomenon, or process of interest (DoD 5000.59, 2007)…”

• “…in the context of SE, a model that represents a system

and its environment is of particular importance to the

systems engineer who must analyze, specify, design and

verify systems, as well as share information with other

stakeholders.

• “… simulations (versus Models) is the implementation of a

model (or models) in a specific environment that allows the

model’s execution (or use) over time. In general, simulations

provide a means for analyzing complex dynamic behavior of

systems, software, hardware, people and physical

phenomena….”

Static Models & Dynamic Simulations

Model Based Systems Engineering (MBSE)

• Formalized application of modeling to support system

requirements, design, analysis, verification and validation

activities

• Beginning in the conceptual design phase and continuing

throughout development and later life cycle phases

• (“A Practical Guide to SysML”)

Model Based SE (MBSE)

Practices for Developing Systems

MBSE Supports:

• Customer Needs

• Operational Concepts

• Specifications/Requirements

• System design/architectures

• Interfaces & Models

• Analysis & Trade-off

• Test plans/procedures

• Life Cycle Support

Moving from Document Centric to Computer based Model Centric

AirplaneATC Pilot

Request to proceed

Authorize

Power-up

Initiate power-up

Direct taxiway

Report Status

Executed cmds

Initiate Taxi

Past Future

MBSE

Interrelationship that Establish

MBSE, UML, SysML & OOSEM

OO

Concept

Fundamental SE Best

PracticesUML (Universal Modeling

Language)/OMG

SW Engineering: e.g.

ISO 12207, & OOA/D &

Agile SW Concepts

SE Engineering:

e.g. ISO 15288 &

Agile SE

Concepts)

Guides, etc. (e.g.

INCOSE SE

Handbook,

SEBOK, etc.

SysML (System Modeling

Language)/OMG

OOSEM (Method)

Fundamental SW

Best Practices

OVERVIEW OF MBSE:

THE FOUR MBSE ESSENTIALS

3. Tools

E.g. Magic

Draw

Customer Needs SE Models & Products

4. Trained

MBSE

Experts

2. Language

Specifications

E.g. SysML,

UPDM, UAF

1. Methods

E.g. OOSEM

MBSE

L. Mark Walker

INCOSE IW10 MBSE Workshop- Mark Sampson page 8

Integrated Systems Engineering Vision

Minimum Turn Radius: 24 ft.

Dry Pavement Braking Distance at

60 MPH : 110 ft.

Thermal/

Heat

Dissipati

on: 780°Ergonomi

c/Pedal

Feedback

: 34

ERGSHydraulic

Pressure:

350 PSISenso

r

MTBF

:

3000

hrs

Power

Rating

:

18

Amps

Hydrau

lic

Fluid:

SAE

1340

not-

compli

ant

Minimum Turn Radius: 24 ft.

Dry Pavement Braking Distance at

60 MPH: 110 ft. 90 ftFigure not include in SE Vision

Modeling Representations

Depend on the Audience, i.e. who is the model for:

Engineers, managers, support personnel, training, etc.

will require difference model representations and

information

The Scope of representations can be a few to many (e.g.

DoDAF 2 has 52 views for one system over its life cycle

The phase of a development or upgrade needs different

and/or tailored views within the model

Models evolve/change during life cycle phases

The level of complexity varies and is dependent of the need

for information by the audience

The supporting information must be provided to the level of

detail needed by the audience

I.E.: Based on the Purpose, Scope, Objectives and Audience

Evolution Life Cycle of Models, Architecture, etc.

10

1

2

3

OVERVIEW OF OOSEM

PROCESSES

OBJECT-ORIENTED SE METHOD

• “Top-down, scenario-driven process that uses

SysML to support the analysis, specification, design

and verification of systems”

– From “A Practical Guide to SysML, Third Edition: The Systems

Modeling Language”, by Friedenthal, Moore, Steiner, Copyright

2015

• Leverages Object-Oriented Analysis and Design

(OOA/D) with Model-Based and Fundamental SE

methods to help analyze, architect, and engineer

flexible and extensible systems that accommodate

evolving technologies and changing operational

needs & requirements

• Facilitates integration with object-oriented software

development, hardware development, and

verification and validation (V&V)/testing

Systems Requirements & Design Activities & Models - OOSEM

Synthesize

Allocated

Architecture

Define

System

Requirements

Define

Logical

ArchitectureOptimize &

Evaluate

Alternatives

Support

Validation &

Verification

Analyze

Needs

Major SE Development Activities

Fundamental SE Development Sub-Activities

Parametric DiagTrade StudyArchitecture Views

Test CasesUser StoriesVerification & TestProcedures

Causal AnalysisMission Use Cases/ScenariosEnterprise ModelMission Concept Document

System Use Cases/ScenariosElaborated ContextSystem Concept DocumentReqts-Architecture Mapping

Logical DecompositionLogical ScenariosLogical Subsystems

Node DiagramHW, SW, Data ArchSystem Deployment

Manage

Requirements

Reqt’sDiagram& Tables

Figure 17.2 (Object Oriented Systems Engineering Method)

Figure 17.2

*Reference: “A Practical Guide to SysML”, second edition

FIGURE 17.5 (ANALYZE STAKEHOLDER NEEDS ACTIVITY)

Figure 17.5

*Reference: “A Practical Guide to SysML”, second edition

Tailoring the OOSEM method

OOSEM can be tailored to meet project objectives and

constraints (i.e. time and money available)

Tailoring is very dependent on the domain and

environment for the system, audience, etc.

Tailoring involves selecting the appropriate level of rigor

to apply to each of the OOSEM activities

Selecting the activities and their ordering

Selecting the artifacts to generate

Selecting the level of detail

Feedback and iterations to develop the Optimum solution

based on current & potential future information and

knowledge

16

SYSTEM MODELING LANGUAGE

(OMG)

SysML DIAGRAMS

SysML

Diagram

Parametrics

New

Behavioral Structural

ActivityState

MachineBlock

DefinitionInternalBlock

Sequence

Package

Spec-Oriented

Un-changed

Modified

UseCase

Reqts

Key

act sd stm uc req par bdd ibd pkg

18

First Stage, Develop Stakeholders’

System UCs, Scenarios & Sequence Diagrams

System Use Cases are a SysMLTM “Spec Oriented” (Requirements) Diagram.

Virtually all SysML and other Architecture diagrams/Models are Derived From & Map To Stakeholders’ System Use Case Diagrams

Copyright © 2014 by Loren M. Walker.

MBSE/SysML Tools

• Many tools support MBSE but vary in their

implementation, look and feel, etc.

• But those that support MBSE must meet the OMG’s SysML

Specifications

• The tools are computer based tools that apply the

specification and associated rules, views, etc.

• The tools capture and manage the models’ views

contents, view and element relationships and all

associated data & information for all views/elements in

One Data Base

• Most advanced tools include ability to interface and/or

share data with other tools that provide further

capabilities

• MBSE SE’s must be trained on these tools to be effective

Integrated Tools

Project Management

CM

/DM

Pro

duct

Data

Manag

em

ent

Requir

em

ents

Manag

em

ent

Engin

eering

Perf

orm

ance A

naly

sis

Verification &

Valid

ation/P

ara

metr

ic

Math

, etc

.

SoS/UAF/DoDAF/ Business Process Modeling/

Unified Profile for DoDAF and MODAF (UPDM)

etc.)

System Modeling

SysML

Software Modeling

UML 2.0

Hardware Modeling

VHDL, CAD, ..

Specia

lty E

ng

ineering

Analy

sis

Personnel Training Required

As shown in the first diagram:

Trained System Engineers in MBSE are Essential

This Training includes:

• Fundamental Systems Engineering Life Cycle Processes

• Includes experience is system developments &

deployments

• MBSE, SysML and OOSEM Training

• SysML Based Tools Training

• Team work with other trained SE, SW and other design

and support professionals

• The ability to work with Operational Customers to

develop System Use Cases, Scenarios, Operational

Concepts, Models, etc. to initiate the development

process

Summary/Conclusions

MBSE is an implementation of Systems and Software

specifications, methods, tools and trained personnel

MBSE integrates Systems/Software Best Practices based on

Guides, Handbooks, Specifications, Research

SysML Computer based Tools are essential with One Data Base

for all views, relationships, information for Models,

architecture, elements, requirements, users/operators, etc.

Implementation of MBSE must meet customer and engineering

domain requirements

e.g. Military, Industries, Customers, Engineering disciplines

Expertise and experience is Essential- i.e. Trained Personnel

Provides Rapid (Agile) Reaction to Life Cycle Changes & Reqts

Applicable to SoS and System Analysis, Upgrades,

Development

23