discuss systems

1Massachusetts Institute of Technology © Ed Crawley 2002

From Value to Architecture

Ed Crawley

Aeronautics and Astronautics

Engineering Systems

MIT


Today’s Topics

• Objectives• Analysis of architecture• A useful tool • Synthesis of architecture


Learning Objectives0) Be able to apply the principles, processes and tools of system

architecting to structure and lead the early, conceptual PDP phase

1) Discuss systems, systems thinking, products, the PDP and the role of the architect

2) Critique and create architecture, and deliver the deliverables

3) Drive ambiguity out of the upstream process

4) Create the concept

5) Manage the evolution of complexity

6) Critically evaluate current modes of architecture

7) Develop the principles of architecting

This is a course in how to think, not what to think


Process for Critical Thinking

• Opportunity, challenge, or reference example identified

• Thinker develops an approach option

• Thinker identifies other options, then analyzes and criticizes the options vs. each other and the “developed” approach

• Synthesized, context-appropriate “best” option is defined


The Role of the Architect

• Defines the boundaries, goals, and functions

• Creates the Concept

• Allocates functionality and defines interfaces and abstractions

The architect is not a generalist, but a specialist in simplifying complexity, resolving ambiguity and focusing creativity


Four Basic Tensions inProduct/System Development

Benefit

Schedule Risk

Cost

Value is Benefit at Cost


The Architect Creates Good Architecture

• Satisfies customer needs• Incorporates appropriate technology• Meets strategic business goals• Meets or exceeds present and future regulations

Is operable, maintainable, sustainable, reliable Can be evolved/modified as appropriate

Can be designed and implemented by envisioned team Can be implemented with existing/planned capabilities

AND IS ELEGANT


Deliverables of the Architect• A clear, complete, consistent and attainable (with 80%-

90%confidence) set of goals (with emphasis on functional goals)

• A functional description of the system, with at least two layers of decomposition

• A concept for the system• A design for the form of the system, with at least two layers

of decomposition• A notion of the timing, operator attributes, and the

implementation and operation plans• A document or process which ensures functional

decomposition is followed, and the form at interfaces is controlled


Architecture - 6 Views

Principles

Methods & Tools

ThemesCasesFrameworksRoles &Definitions


Analysis of Architecture

• Form, function and concept - the architecture

• Upstream influences• Downstream influences


A Definition• Architecture

– The embodiment of concept, and the allocation of

physical/informational function (process) to

elements of form (objects) and definition of

structural interfaces among the objects

• Consists of:– Function– Related by Concept– To Form

Form

Fu

nc

tio

n

Concept


Architecture – Form

Suspension bridge

Cable-stayed bridge


Product Attribute - Function

• Function is the activity, operations, transformations that create or contribute to performance

• Function is a system attribute, created by the architect

• Function is associated with form, and emerges as form is assembled

• Function can stated in solution neutral form, as a verb plus noun, and with a limited syntax

• Externally delivered function is linked to value of a product


Function is Associate with Form

• Change voltage proportional to current

• Change voltage proportional to charge

• React translation forces

• Carry moment and shear


Concept - the Mapping of Form to Function

• A system vision which maps form to function and embodies working principles

• Is in solution-specific vocabulary - it is the solution• Is created by the architect• Must allow for the execution of all functions• Specifies the vector of design parameters, which, when

selected, will establish the design

• Is an abstraction of form, or form is a specification of

concept FormF

un

cti

on

Concept


Dominant Upstream Influence on Architecture

Regulation

Corporate,MarketingStrategy

Customers

CompetitiveEnvironment

Technology

Architecture

Need Goals

Downstream Strategies,

Competence

Form

Fu

nc

tio

n

Concept


Product Attribute - Need

• Need is defined as:– an overall desire or want– a necessity– a wish for something which is lacking

• Can also include opportunities to fill unexpressed needs• Exists in the mind of the beneficiary (outside the

enterprise)• Expressed often in fuzzy or general (i.e. ambiguous)

terms• Is interpreted (in part) by the architect


Product Attribute - Goals• Goal is defined as

– what it accomplishes, its performance– what the designer hopes to achieve or obtain

• Expressed in the precise terms of Product Development• Will include goals derived from user Needs (goals from

beneficiaries) i.e. the external functional goals• Will also include goals from corporate strategy,

regulations, competitive analysis, etc.• Embodied in a statement of goals (requirements ?)• Is defined (in part) by the architect• Exist within, and under the control of the enterprise, and

are traded against other attributes


Framework for Downstream Influences

Implementation

Evolution

Operations

Architecture

Design

Operational sequence and dynamic behavior

Operator (training, etc.)

Operational cost

Form

Fu

nc

tio

n

Concept


Product Attribute - Timing• When the system operates, the time sequence of events• Has two important aspects

– Operational sequence– Dynamic behavior

• Operations sequence is the total set of steps or processes that the system undergoes, inclusive of the primary process for which it is intended– Including set up, take down, stand alone, contingency and

emergency operations

• Dynamic behavior is the detailed timing of steps, their sequence, start time, duration, overlap, etc.


Overall Operational Sequence

Waiting in storage

Retrieving, connecting, powering-up,

setting up, initializing

Loading, preparing

Process only ops.

Contingency ops.

Emergency ops.

Archiving, unloading

Terminating, disconnecting,depowering, storing

Inspecting, repairing, calibrating, updating,

maintaining

Executing Primary Process

OPERATING

Store

Get ready

Get set

Go

Get unset

Get unready

Fix


Product Attribute - Operator• Who will use/execute the system• Necessary for products with human

agents/operators/supervisors [which ones don’t?]– most important for human-in-loop (e.g. aircraft,

bicycle)– important for direct human operation (e.g. lathe,

wheelchair, calculator)– for other products, can be considered part of

interface/constraints (e.g. human factors design, industrial design)

• Because of the unique issues of human performance and safety, it is useful to keep separate as an additional attribute


Product Attribute - Operations Cost

• Operations Cost is a product attribute• How much it will cost to operate the system• This is the recurring operational related costs

– Operator and other personnel– Training– Maintenance and (nominal) upgrades– Consumables– Indirect operating costs (insurance, etc.)


Holistic Framework for Attributes of the Product and its Operations

globalwhy

thesystemis built

needopportunity

globalwhat

thesystem

accomplishes

goalsperformance

globalhow

thesystem

acts

functionprocess

globalwhere

theelements

are

formstructure

globalwhen

thingsoccur

timingdynamics

globalwho

doesthem

operatoruser

globalhow much

doesit cost

costexpense


Other Downstream Processes

• The system must be designed, so it must be architected in such a way that design can proceed smoothly and efficiently

• The system must be implemented, so it must be architected for manufacturability, coding, integration, test, and verification

• The system may evolve and be updated, so it must be architected with a view towards these changes - Evolution is really just a recursive pass through conception, design and implementation

• Each has its own who, what, where, when, ...


Qualitative PDP - CDIO

Impl.Schedule

Impl.Team

Impl.Tools

ProcessFlow

Impl.Goals

CustomerCorporateSocietal Needs

DesignSchedule

ProcessMethods

DesignGoals

NRECosts

ProductOperator

ProductGoal

OperatingCosts

Impl.Costs

ProductForm

Product Function

DesignTools

DesignTeam

Product Timing

Conceiving

Designing

Operating

Implementing


Business Strategy

Functional Strategy

Customer Needs

Competitors Program

plan Business

case

Generic PDP

Conceive

Mission Conceptual

Design

Goals Function Concepts Regulation Technology Platform plan Supplier plan Architecture Commitment

Requirements definition

Model development

Requirements flowdown

Detail decomposition

Interface control

Design

Preliminary

Design

Detailed

Design

Design elaboration

Goal verification

Failure & contingency analysis

Validated design

Implement

Element

Creation

Integration,

System Test

Operate

Life Cycle

Support

Evolution

Sourcing Implementation

ramp-up Element

implementation Element testing Element

refinement

Product integration

Product testing

System testing

Refinement Certification Market

positioning Delivery

Sales, Distribution

Operations Logistics Customer

support Maintenance,

repair, overhaul

Upgrades

Product improve-ment

Family expansion

Retirement

Envision Design Develop Deploy


A Tool - Object Process Modeling• Object: that which has the potential of

stable, unconditional existence for some positive duration of time. Objects have states.

• Form is the sum of objects • Process: the pattern of

transformation applied to one or more objects. Processes change states.

• Function emerges from processes• All links between objects and

processes have precise semantics

Objects

Processes


Process and its Links

• A process is associated with a verb and stateless• There are a family of about 5 types of links from

process to object• A process changes the states of its operand(s)

through input and output links

• Transporting changes person from here to there.

Input link Output link


Summary Object-Process Links

• P affects O (affectee)

• P yields O (Resultee)

• P consumes O (Consumee)

• P changes O (from state A to B).

• P is handled by O (agent)

• P requires O (Instrument)


Emergence

• A process can be zoomed into sub-processes• A process emerges from sub-processes• The process and sub-processes are not linked in any

explicit manner, as the object decomposes into parts• Emergence is a powerful feature of systems - parts

and sub-processes can come together to cause a process to emerge

• Emergence sometimes yields the anticipated processes, sometimes does not yield the anticipated process and sometimes unanticipated processes


Synthesis of Products

• Parallel processes: Architecture & Business Case

• Tracing value to architecture• Ambiguity, creativity and complexity• Conclusions


Parallel Cycles

• The parallel cycles end when:- The technical architecture “closes”- The business case “closes”

• The outputs are products with value to customer and profits with value to share holder, while providing appropriate value to society and workforce.


Intent

• An Intent is– What the purpose is– What someone hopes to achieve or obtain

• Is always defined by someone• Useful to create a special symbol for this information

object - supposed to remind you of an arrow - where you are going

Intent


Function - A Formal Definition

• Previous Definition: the …transformation…that contribute to performance…the actions…for which a thing exists

• Function is intent plus process

Intent

Process


Value - Formal DefinitionsValue is delivered when the primary external process(es)

acts on the operand in such a way that the needs of the beneficiary are satisfied at a desirable cost.

Delivering Primary Process

Operand

Intent on process

Has

Beneficiary

Needs

ProductObject

Interpreting &Incorporating

Value Delivery

Value Identification

Value: “how various stakeholders find particular worth, utility, benefit, or reward in exchange for their respective contributions to the enterprise” Murman, et al. LEV p178

Value Proposition


Product Systems and Value• Products include Goods,

which are objects which implicitly execute a process

• Products include Services, which are processes enabled by implicit objects

• In both cases, the value to the primary beneficiary is in the process, not the object

Products

Services

ImplicitProcess

Goods

ImplicitObjects


Whole Product System

• The whole system is the array of objects necessary to deliver the externally delivered process to the operand(s).


Value to Intent • Start by examining the

operand associated with value

• Next identify the attribute of the operand whose change is associated with value

• Next define the transformation of the attribute associated with value, in solution neutral form

This will reduce ambiguity and lead you to a value focused, solution neutral statement of intent on process


Concept

• Concept: a system vision, which embodies working principles, a mapping from function to form

• Choose from among the system operating processing that specialize to the desired solution neutral, value related process

• Specialize the related generic concept to the product form

This is the exercise of creativity

Concept

Five primary functions. McGee, deWeck


Capturing Intent

• Once the system is modeled or built, the “attribute transforming” process and “concept” object vanish

• The “attribute transforming” can be captured as an intent object

• The concept usually remains implicit, represented by the operating process and concept specialization


Decomposition of Function and Form

• Identify form of the whole product system

• Zoom the processes of function

• Decompose the form of the product object

• Establish the object process links


Form and Function - Cooler• The whole product includes

the ice, food, supporting surface, heat load, light and operator

• Chilling zooms to the stated processes (using process precedence framework)

• Cooler decomposes to box and top

• Map objects to processes to determine object-process architecture

Establishing the complexity of the object-process architecture


Structure of Form - Cooler

• Examine the interactions implied by the decomposition of form

Establishing the complexity of the object-object architecture


Form and Function - Refrigerator• More one to one

correspondence of objects and processes

• Note the whole product elements suppressed:– Food– Support

structure– Heat load– Operator


Structure of Form - Refrigerator

Considerably more object - object complexity


So Why Refrigerators and not Coolers?

• Refrigerators have significantly more complexity than coolers

• Refrigerators have more functions, performance and robustness than coolers.

Principle: underlying and long enduring fundamentals that are always (or almost always) valid.

Is a principle lurking here?

Massachusetts Institute of Technology © Ed Crawley 2002

Robust Functionality Drives Essential Complexity

• Essential complexity is that which is essential to deliver functionality before gratuitous complexity slips in

• Functionality drives complexity in any given concept

• But “Functionality” is often defined as a surrogate for a much broader set of functions which the product will actually be use for.

• Therefore, it is the (often implicit) robust functionality which drives essential complexity

A Principle


Conclusions

• Architecture requires consideration of form and function, related through concept

• Value derives from function• Starting with the operand, its transformation

identifies concepts which deliver value• Concepts elaborate into architectures which have

form-function and structural complexity• Essential complexity is accepted to deliver robust

functionality

discuss systems

Education

appropriate technology

architect function

analysis of architecture

form functionconceptconcept15

abstraction of form

mapping of form

performance function

assembled function