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Installing an MBSE Process, Part 2

by Eric Barnhart 1 Comment

Introduction

In part 1 of this series, I presented several of the approaches companies will use to address model-based systems engineering. All of those approaches in part 1 are doomed to be failures. Now let’s take a look at approaches that have been demonstrated to be successful.  Part 2 addresses how to nurture an MBSE initiative.

Crawl-Walk-Run

Crawl

Crawl Before Walking, Walk Before Running

One of the overarching principles I advocate for bringing MBSE to a company is the Crawl-Walk-Run approach. This was an overarching principle used at one company where our team successfully bootstrapped an MBSE process. It’s actually quite simple; learn to crawl before you try to walk, learn to walk before you try to run. Trying to go right from laying on your back to running a marathon is bound to end in tears, skinned knees and hands, and bruised egos. Going straight from non-standard functional block diagrams in Visio to SysML internal block diagrams in Cameo Architect will end pretty much the same way, plus cost a lot of money. Don’t make that mistake. Start with the basics, and build up from there. Crawl-Walk-Run applies to all the following sections.

Preferably Pick a Prepared Process

One of the earliest things a company must do as part of its MBSE initiative is to select an MBSE process to implement. I suggest selecting an established process, such as OOSEM from INCOSE, IBM’s Rational Harmony SE Process, IBM Rational Unified Process for Systems Engineering, Vitech Corporations’s STRATA process or one of several others. Why an established process? If your company is new to MBSE, it most likely doesn’t have the skills or expertise to develop a custom process. Start with something that already exists.

There are no hard and fast rules for selecting a process, as it depends on the needs of the company, its existing engineering knowledge base and the expectations of its customers. There are some heuristics you can use.

If object orientation is completely foreign to your technical staff, as well as your business development and project management staff, then selecting an object-oriented process is ill-advised. It’s easier to work with concepts your staff already understands, or that they can easily pick up on. You need to get the staff crawling before advancing to either walking or running.

If your typical customers prefer reports and drawings in a particularly format, then it’s best to select a process that supports these reports and formats. For example, if your primary customers and their products are very mode and state focused, your process should revolve around handling modes and states. These require a different approach and different process from products that are user-centric and are use case driven.

Customize the Complexity

Whatever prepared process you select, you will need to customize it to your own needs. Prepared processes are designed for any situation engineering can throw at them, and are generally complex. Most of your customization at this point will be subtracting unneeded complexity from the process. If the process has a series of steps that don’t apply to your company, pull them out of the pre-defined process as part of your customization. If your company is used to performing similar steps in a different order, feel free to change them up. Again, start crawling for your initial deployment before you try to walk.

With all this customization, you’re going to need to document your customized process. If it’s not written down, does it exist? If process documentation requires felling some trees in the forest and nobody reads the resulting paper, did it ever happen? Write your process down and formalize it. Be sure to apply your local configuration management processes for company processes, and make sure the process documents get distributed.

Merge the Maps

A pre-existing process will define the MBSE process using its own map of the process territory. You will need to create a cross-reference between the MBSE process and your standard engineering process. This is necessary for two reasons. First of all, you need to make sure your selected and customized MBSE process covers all significant aspects of your standard, non-MBSE process. For example, if your standard process requires functional decomposition, you should be able to describe how the MBSE process also covers the equivalent of functional decomposition, even though the details will be different. If you can’t make a cross reference between the two, you will need to understand and explain the exception.

Secondly, your engineers will need to grasp what they will be doing in an MBSE environment. Mapping an MBSE process against a non-MBSE process provides a necessary degree of familiarity for engineers. When they put the MBSE process into practice, they’ll be able to recognize that the new practice solves the same problems they were addressing with the old practice.

Without a “Rosetta Stone” for your process, your engineers simply won’t be able to translate it to something they understand. If they don’t understand the what and why of their tasks, they will put up resistance to your new process. Experience has shown that engineers can be stubborn that way.

Wield One Tool Well

Now that you’ve got a customized, MBSE process that suits your company needs, you’re going to have to put it

Hammer

Only One Tool at a Time

into practice using an MBSE tool. Visio and Powerpoint are not going to make the cut for real MBSE, and using Excel databases to hold model entities actually somewhat scares me. (It should scare you too.) Pick a tool, but pick one. That’s right, you’re still at the crawling phase, and you want to have singular focus on a single MBSE tool. Find ones that support your process (you probably already know the tools) and make your best deal with the vendor. You’re going to need a lot of licenses and vendor support to make this work.

So far, you’ve got an MBSE process documented and you’ve got an MBSE tool. The next step is to translate your process into actual practice.

Pilot Projects Perfect Your Process for Practice

The next step in crawling from a set of MBSE process documentation to standing up a MBSE practice is to execute a pilot project using the new process. I recommend a simple project executed by the MBSE deployment team. The pilot should be common to your business and easy for the engineers to agree upon, once they see it. During this pilot, the deployment team learns to walk by executing their process. The team uses the defined methodology and selected tool, but perhaps more importantly, the team
documents every decision, menu selection and mouse click.

The methodology might very well start with a group sketching on white boards and making decisions in analysis. Document all the steps. For example, why is this a use case and some other alternative is not? Explain it. Why is an activity diagram using a fork here but a decision branch there? Explain it.

Next move the artifacts into the tool. How is a new project created? Show the menu selections and mouse clicks. How do you organize a standard project? Show how to create packages and folders, or your tool’s equivalent. How do I build a functional behavior diagram? Again, show all the steps in the tool.

Once you complete your pilot project, you’ll have a small team of experts stood up and ready to walk. Plus you’ll have all you need to create material for the next phase of nurturing.

Embrace Enthusiasm for Education and Training

As I wrote about before, you can’t just throw a process, or even a detailed practice, out into the engineering community and expect engineers to embrace it. Like an aged and experienced elephant, the engineering team will go where it wants and follow the familiar trails. Experience has shown that engineering teams can be stubborn that way as well. You can’t force a team, or an elephant.

But you can train it.

Training Lecture

Effective Training is Essential

In fact, you need to make a commitment to training all of your system engineers in the MBSE process, and more importantly in the practice of it using the tool set. By “commitment,” I mean budget and time. If it’s important to the company, then the company will put money and time behind it. Money and time are the currencies of value in the language of corporations. A company that trains all its system engineers in MBSE clearly communicates the importance the company puts on the process, practice, and use of MBSE.

 

On the other hand, a company that expects engineers and instructors to participate in training during off days for free, or to take generic web-based training on their own time is communicating a very clear message: “MBSE training is not important. It’s value to the company, in our monetary language, is a big fat $0.00.”

Communicate the right message to nurture your MBSE initiative.

Call a Coach

Although your engineering teams will be well trained and ready to put the MBSE process and tools into practice, they are not really experts yet. They are walking and not yet running. They’re still developing paths through the MBSE jungle. You can make it easier for them by having a MBSE coaching team available for teams to call on demand. Instead of fumbling through an initial MBSE program startup, the engineering team can have a small team of experts available to help them, offer advice and make the program bootstrap go much faster.

Summary

The alliterative steps I’ve outlined here, from Picking a Prepared Process to Call a Coach, all support an MBSE initiative from crawling through walking. These aren’t all the good ideas for nurturing an MBSE initiative, but I consider them the main ones. If you have more ideas or additional experience, feel free to share in the comments.

The more effort you put into these nurturing efforts, the more likely you are to successfully stand up an MBSE process initiative and move it forward to the benefit of your company. Walking forward will take you far, but as your system engineering skills improve, you’ll want more options, more tools and higher quality outputs. You’ll probably want to add new MBSE tools and training beyond your initial selection so you can satisfy more customers. Or add new analytical techniques to your repertoire and train the team to use them in the tool. When you reach this stage you can truly say you’re up and running, and your MBSE initiative has reached it goals.

In the meantime, keep calm and MBSE on.

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Example Map – the Simple Requirements Model

(continued from part 2)

What makes a map of System Engineering valuable?  How does a system engineer use a map to get from one place to another in the engineering process?  How does a map support decision making?

In a previous article, I addressed what it takes to build a map of the Systems Engineering territory, or an information schema for SE data.   I included a real map of a schema created for a tool back in the ancient days of the 1990’s.  That map was far too complicated to explore for an introductory discussion, so I put together a very simple map of systems engineering that I expect many SEs can understand and agree to, at least in principle.  I’ll call it the “Simple Requirements Model”, or just SRM.

In the rest of the article I’ll explore the SRM to establish some basic concepts about managing maps of information for systems engineering.

Diagram of a SE entities and relationships

The Simple Requirements Model (SRM)

Entities

The model graphically shows entities using blue rectangles.  Each entity is a collection of tightly coupled data which collectively define the entity, and uniquely identify that entity.  If you are an aficionado of relational databases, you might think of these entities as rows in a table.  If you’re an advocate of object-oriented methods, you might consider the entities to be objects that realize a particular class.  For this high-level discussion, the specific implementation is irrelevant.

Entities also have a set of business rules, which are unique to the type of entity.  The rules define processes for creating an entity, establishing entity validity, how to perform configuration management for the entity, and others.  The business rules are not visible in the entity data; instead the business rules define the processes and operations behind the entities.  Business rules will be unique to the organization that creates the system engineering map.  For this introductory level discussion, the business rules are kept to a minimum.

Relationships

Entities have relationships between one another shown by lines with arrowheads to indicate directionality of the relationship.  Relationships show that entities have a correlation or linkage between them.  To capture the meaning of that linkage, every relationship needs at least a name to define it, and rules for how the linkage is made.

Consider your relationship to an automobile.  You might be the driver of the car which is established when you get into the drivers seat, start it and drive it off.  You might very well also be the owner of the car, which is established by the title to the car and kept by a local government entity.   You and the car are two very different entities, and have two (or more) very different relationships.

Exploring the Map

Now that we have some basics, let’s look  at the SRM map in more detail.

As described above, a well-constructed map of an information territory, or domain, represents well-defined entities with not only a name and perhaps a descriptive definition, but also with a set of attributes necessary to characterize the entity in the particular context. Each of the elements in the SRM needs its own set of attributes.  Let’s explore the entity at the center of the SRM, the requirement.

So what is a requirement?  According to INCOSE, a requirement is:

  1. A condition or capability needed by a user to solve a problem or achieve an objective.
  2. A condition or capability that must be met or possessed by a system or system component to satisfy a contract, standard, specification, or other formally imposed documents.
  3. A documented representation of a condition or capability as in (1) or (2)

For our purposes, a requirement is most closely like definition 3, the documented representation of 1 and 2.  Since it is a defined element of this model, we shall refer to the entity as a «requirement», where the guillemets («») act as a flag that we are talking about a well-defined element of the SRM.

(If you choose to use an indicator of a defined entity in your documentation, you can choose any indicator you like, or no indicator at all.  I advocate flagging any reference that has a well-defined meaning to let readers know they’re looking at something using a precise definition, and not a random or ambiguous term.)

Not only does the «requirement» have a definition, it is also characterized by a specific set of attributes that describe the «requirement» and only the «requirement».  Here is a look at the attributes of a «requirement» in the SRM:

Attribute table

Attributes for a «Requirement» in the SRM

In the context of the SRM (and frankly, in almost all practical contexts) a «requirement» can be characterized with only two required attributes, a unique ID and the text of the user need.  (SysML defines exactly these two.) In the SRM there are only 15 requirement attributes defined, and only two are mandatory.

Since the «requirement» entity is at the center of the SRM domain, the next step will be to see how it relates to the other entities in the SRM.

«Requirement» «has parent» «Requirement» Relationship

A set of «requirement»s tends to have a hierarchical organization, so a «requirement» can have a relationship to another «requirement» called its parent, or «has parent».  The relationship is shown with a directed arrow.  The hierarchy can be discerned by recursively following «has parent» relationships until we find a «requirement» that has no parent «requirement»s.

in a more complex model, the «has parent» relationship might be replaced or complemented with more detailed relationships, such as «decomposes», «disambiguates», or «derived from».  The SRM uses the simpler «has parent» relationship.

«Document» «reports on» «Requirement» Relationship

A hierarchical set of requirements is usually represented not in a simple list, but in a document or specification.  A «document» is a separate entity from a requirement because a document has a different set of characteristics.  Documents will have a formal ID, title, author, revision, multiple sections and subsections and release sensitivity.  None of these apply to individual requirements. It makes sense then that a «document» should be stored as a separate entity from a requirement.

This is significantly different from legacy DOORS 9.x implementations, in which requirements and documents are misguidedly mixed together into a confusing morass. (It is possible to separate the two using DOORS 9.x, but that requires the design of the database to differ from the originally intended design of the DOORS application.)

Furthermore, «document»s differ from «requirement»s because «document»s have different methods to operate on and maintain them.  Instead, «document» «report on» «requirement»s, or inversely, «requirement»s are «reported on» by «document»s.

Publishing a specification is a process of selecting the «requirement»s from a model based on a query of the requirement allocation to a component, and then building a «document» to organize and report on the selected «requirement»s.

«Requirement» «allocated to» / «satisfies» «Component» Relationships

A «requirement» states what the customer needs, but that need is delivered as a «component» of the overall deliverable system.  This is how the SRM ties together the descriptive model of «requirement»s with the structural architecture model of «component»s.  A typical business rule maintains that a «requirement» is allocated to exactly one «component». (If it were allocated to more than one, then the «requirement» would be stating more than one goal and needs to be decomposed into multiple requirements.)   The inverse relationship says that a «component» satisfies a «requirement».  A «component» can satisfy multiple «requirement»s.

A «component» is a separate entity from a «requirement» because it has unique characteristics that describe it as a physical entity.  «Component»s will have a unique identifier, a set of functions, a set of constraints, physical characteristics that describe it as a controllable physical item, procurement attributes and others.  In addition, «component»s are managed and controlled as configuration items, not as «requirement»s.

«Component» «has parent» «Component» Relationship

The architecture of a system generally is a hierarchical structure of «component»s. Similar to a «requirement», a «component» has a relationship to a parent «component» via the «has-parent» relationship.  Traversing the «has-parent» relationship reveals the structural hierarchy.

«System» «is a type of» «Component» Relationship

In the SRM, «requirement»s are «allocated to» «component»s, which allows some flexibility in how a business defines a «component».  Since I’m describing a system engineering model, the model needs to have a «system» in it.  In the SRM, I show that a «system» is a specific kind  of «component» using the relationship «is a type of».  In a larger and more useful SE model, the «system» and «component» would have a much more detailed model surrounding them and describing more relationships.

«Requirement» «satisfied during» «Increment» Relationship

In many projects, the development effort will be spread over several phases, or implemented in «increments».  A business rule might state that a «requirement» will be «satisfied during» exactly one increment.  (If it were «satisfied during» more than one, then the «requirement» would be stating more than one goal and needs to be decomposed into multiple requirements.)

«Test Case» «verifies» «Requirement» Relationship

In order to prove that a «requirement» is met, the «requirement» needs to be tested and verified.  A «test case» defines the testing and verification approach and is related to multiple «requirement»s through the «verifies» relationship.  A «test case» is a unique entity from a «requirement» not only because it has unique descriptions and goals, but is finalized during a later lifecycle phase of the program, generally after the requirements set has been baselined.

«Change Request» «modifies» «Requirement» Relationship

In order to control changes to a requirements set in an orderly fashion, each «requirement» is generally placed under control of configuration management.  A business rule might state that a «change request» is necessary before modifying a «requirement».  The «change request» might have attributes that look a lot like the attributes of a «requirement», as well as additional attributes for status and tracking of the request.  The «change request» is handled differently from a «requirement» and lacks the other relations of a «requirement».  Given these factors, the «change request» is an independent entity in the SRM.

«Requirement» «describes» «Capability» Relationship

A «requirement» states what the customer needs, but ultimately the customer has a specific desired effect the customer wants to see in the end product.  That desired effect is captured by a «capability» entity.  Typically multiple «requirement»s will «describe» a «capability».  This is how the SRM ties together the descriptive model of requirements with the results-driven behavioral model of «capability»s.

«Component» «implements» «Capability» Relationship

Finally, the «components»s of the end product must exhibit well-defined, desired behavior to satisfy the customer.  The SRM models this by showing that a «component» «implements» one or more «capability»s.  A business rule might allow a «component» to «implement» many «capability»s, but insists that a «capability» be implemented by exactly one «component».  (If a «capability» were implemented by multiple «component»s, then the «capability» would need to be decomposed into multiple subcapabilities.  The SRM, being simple, does not support this.)

Map Making Lessons

This map is so simple the reader no doubt found multiple deficiencies and inconsistencies between this simple model and their own company’s system engineering approach.  Still, this simple example provides a background to learn a few lessons.

One of the first lessons learned is that creating this very simple map, or schema, is a surprisingly tedious process.  It was probably even tedious to read it.  (Sorry about about that.)

Part of what makes it so tedious is that we feel we already know these entities and relationships.  If we knew them so well, they would be written down, wouldn’t they?  If everybody knew them by the same exact definition, wouldn’t the system engineering process go much faster and be more accurate?  Despite feeling that we know them, almost no one has really taken the time to be explicit with them.  (I’m sure a Vitech Core sales representative will chime in here.  Feel free to comment.)  As a result, when moving from company to company, and even project to project, we waste a lot of time reinterpreting our map for the SE process, and stumbling over minor misconceptions and terminology.   SE is a discipline of communication and information management, yet we fail to do that for ourselves.

If your company actually goes to this level of detail, or more, please let me know in the comments.  I only encountered one organization in my 35 year career that actually gave this much thought to the engineering process.

Another humorous lesson is that using guillemots is itself tedious, especially in an article that references the underlying entities of a model a lot!

And we’re not done yet.  The next lesson to be learned is captured in the final installment of information management in systems engineering.  I’ll explore how to use the SRM to satisfy the needs of engineering users.

DISCLAIMER:  I am tool agnostic.  I am not associated with any tool or vendor, nor do I benefit from any tool sales or stock.

(part 4 coming soon)

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Installing an MBSE Process (part 1)

Introduction

Moving a company from traditional engineering processes to model-based processes (or any new process for that matter) is a tricky endeavor.  It’s easy to start enthusiastically, and then witness the whole effort crash and burn, or just fade into oblivion.  For those of us who are enthusiasts for modern practices, this can be extremely frustrating.  For those of us who have been given the tricky task of implementing a model-based process in our organization, it can be demoralizing to see our efforts fail. What can we do about these outcomes, other than run away in fear from a presumed MBSE monster?  If you want to avoid a monster movie playing out, this two-part article is for you.

plane-828826_640Over my decades of systems engineering, I’ve seen many variations of attempts to install modeling processes of some form or another into the system engineering process. I’ve learned to predict accurately whether a company will succeed or fail with their efforts, and I can predict it as early as the first 90 days of the start of an MBSE initiative.

Pretty bold claim? Well, I see things. I see dead processes. There are a lot more of those than living ones.  Part 1 addresses the issues that destroy your attempts at updating your process, and Part 2 addresses key elements to make it succeed.

Let’s start by getting a little more analytical about why efforts fail.

Part 1: Don’t Kill the Baby

You don’t want a process that’s DOI (Dead On Initiation) do you? You want an MBSE process that survives and benefits your organization. Before I tell you how to be successful, I feel I should give you an overview of what kills your MBSE process. After all, it makes no sense to nurture a new process at the same time you’re strangling it to death. So first take heed of these cautionary points to “process-proof” your organization before starting an MBSE initiative.

Grass roots efforts are doomed to fail

plants-2411458_640If you are relying on grass-root efforts among the engineering staff to boot-strap your MBSE initiative, you’re dooming yourself to failure. Sure, the grass-roots, die-hard MBSE engineers are the ones who will jump aboard the MBSE band wagon when it shows up (if at all.) They even provide the fertilizer to help the seeds of MBSE to grow. On the other hand, they cannot direct other engineers to follow MBSE standards, nor direct change in programs or organizations.

If you’re relying on grass-roots efforts, your MBSE initiative has already succumbed to drought, chinch bugs and died below the surface.

Dropping tools onto engineers computers is just fumbling the ball

frustrated_at_computer_640So maybe you’ve decided to fork over some of your budget and purchase a set of licenses for the latest and greatest MBSE tool. Then you push the tool to all your engineer’s computers and let them have at it. Nice thought, but ultimately a bad idea. The engineers probably don’t have the time or charge number to learn how to use the tool. If they do find time, each engineer will fumble around until they develop their own approach and methods. There is no ability to transfer tool skills between work groups or programs if everybody is engineering their models differently.

If you think all you need is an MBSE tool pushed out to engineering, you are sadly mistaken. When push comes to shove, your lack of attention to your tool roll-out will have pulled your MBSE initiative to its death.

Executive mandates are ignored in the trenches

Maybe, in a fit of hubris, you decided to issue an executive mandate to use MBSE techniques on all programs, and use the company selected tool. I’ve even heard the suggestion to make MBSE techniques part of the yearly performance review criteria. On the surface this seems to make sense. It shows the company backs the MBSE initiative.

signed_document-640On the other hand, down in the engineering management trenches, the staff knows there’s a much more important mandate: get the job done on schedule and make a profit. As a result, the MBSE implementation will be absolutely minimal, that is, just enough to check the box that the MBSE mandate was followed. MBSE will ultimately have little or no impact on the program.

If you think all it takes to get MBSE off the ground is a mandate from the VP of Engineering, then feel free to tick that box on your management checklist. The box is checked, but the entire MBSE initiative checked out long before the use case analysis began.

Exceptions multiply like weeds

Maybe you’re smarter than most organizations and bootstrapped an MBSE initiative without falling into any of the previously described traps. Did you recognize that sometimes MBSE will not be appropriate, or that some engineers or manager will not be up to speed when necessary? If so, you’ve probably granted some exceptions to the MBSE process, or have been otherwise lax in enforcing your process. Maybe the engineers are bringing Visio and PowerPoint versions of their diagrams to peer reviews, or even to more formal reviews. After all, Visio makes a more pleasing diagram than most MBSE tools, right? Maybe the engineers are skipping use case analysis because they see no value to it. After all, they never needed to do it before. It’s easier to follow the old, familiar path than try this new MBSE stuff. The engineers can make the case that following the old path is faster than doing all these new, unfamiliar MBSE processes.

spring-weeds-640Sure, Visio drawings might look better, but you can’t accurately engineer a solution using non-standard artist’s renditions of the proposed solution. You need the engineering drawings, and those come out of your MBSE process and tool using standard notation. You need ALL the engineering artifacts in your process to be in your MBSE tool’s database in order maintain correct and useful relationships from top to bottom.

And of course, there is a learning curve to deal with in any new endeavor. Don’t forget, the OLD processes had learning curves too.

Do remember, that if you allow exceptions whenever the engineer feels like it, you’ll see everything grow except the MBSE process you wanted.

Bad Management Practices You Can’t Change

Naturally, these are not all the anti-patterns leading to failure. There are other systemic issues to be aware of. Changing executive management in the middle of an MBSE roll-out will often kill off the initiative. Changing corporate values to satisfy the shareholders at the sacrifice of company performance will do the same thing. These are not MBSE specific issues, but overall management problems than run rampant through corporate culture. There’s little an engineering manager can do to fix these.

On the other hand, the engineering managers in charge of MBSE processes do have things in their power they can leverage to make MBSE work. Those will be addressed in part 2.

 


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