I OCD Modeling, Shared Vision
CS577a Fall 2000
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Modeling
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Why Model?
What makes computers useful?
Can faithfully represent a conceptual system in a particular context outside of real time/space. That is.... Computers support software models. Software implementations are representations (models) of real-world conceptual systems. 3
Model Clashes: Faithfulness
Consistency:
(I) A constraint set forth by one model element does not violate a constraint elsewhere (e.g. inter-model clashes such Waterfall and IKIWISI) (II) The same name is never used to denote two different model elements (e.g. domain-entities and system-components, [internal and external] increments) (III) Two different names are never used to refer to the same model element (e.g increment and build)
Soundness: all elements (including the product itself) deduced from a model satisfy all models
Ex. All requirements must be consistently represented in the software
Ex. Requirements are eventually functionally decomposed into operations (operations can only be carried out by objects) Ex. Gantt/Pert charts must represent the process strategy
Coverage: all model elements map to other model or nonmodel elements
Ex. All operations must eventually be mapped to objects Ex. All level of service requirements must have a verification activity
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People-Technology Gap: product models
System Concept General People
People General Domain ion Descript System Design Specific System Analysis System n mentatio Imple
y echnolog T
System Representation Technology Specific 5
People-Technology Gap: product models
Thoughts Natural Language Programming Language Instructions
DD
A
D
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People Characteristics of People 1. Non-linear 2. Abstract 3. Continuous 4. Context sensitive 5. Active 6. Creative 7. Inconsistent 8. Need doughnuts 9. Semantic 10. Highly parallel (small task) 11. Approximate (PAC, PACE) 12. Learn 13. Do as they want 14. Make choices 15. Flexible (usually) 16. Desires power 17. Informal
Technology Characteristics of Computers 1. Linear 2. Concrete 3. Discrete 4. Context free 5. Passive 6. Logical 7. Consistent 8. Need batteries 9. Syntactic 10. Sequential 11. Exact 12. Represent 13. Do as they're told 14. Compute 15. Rigid 16. Needs power 17. Formal
"[Software] people tend to focus more on the technologies context rather than the customer." - E.Port
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targeted development
Implementation Design Analysis Domain Description
Responsibilities Results Goals
{Time, information}
"Center Out" approach
Customers
(Why/Where)
Domain Experts
(What)
Developers
Iterative development
(How)
Technology
(Do)
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Development Parts
Domain System Model: Description Analysis System System Design Implementation
Concepts
Entities
Components
Objects
Structures
Audience:
Project Domain Implementers Computers Constituents Experts
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Modeling versus Documenting
MBASE describes models, how to build them, integrate them, and ways to communicate them. Documentation is a necessary consequence of modeling
Why? What are models... how are they used... Important observation: documenting solidifies a model
Communication is an essential part of the collaborative development approach Avoid documenting for documentation's sake!
Everything you document should be the result of modeling activity Everything you document should have value and meaning to stakeholders (think about risk here)
The models are the documentation!!! The documents are the models!!!
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The OCD Models
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Purpose of OCD
Describe the overall context of the system to be developed, why it's being built, what exists now, and where the project is starting from Describe to the stakeholders of the system to be developed ("developed" is meant to include such terms as "enhanced", "updated", "re-engineered", "automated"), how the system will work in practice once it is deployed Enable the operational stakeholders to evolve knowledgeably from their current operational concept to the new operational concept, and to collaboratively adapt the operational concept as developments arise, to make clear the value of developing the new system Establish goals and other success criteria, establish basis of value assessment (for use in FRD Business Case Prepare for evolution: how to transition from current to new operational concept, what future changes may be needed.
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OCD High-Level Dependencies
WinWin Negotiations Give:
System Project Capabilities Goals and Constraints Levels of Service Terms (CDL) for the domain description
OCD Yields:
Project, System and Level of service Reqs for SSRD Domain Description and Initial Analysis for SSAD Stakeholder and Organizational Responsibilities for LCP Business Case Analysis parameters for FRD
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OCD Completion Criteria
LCO
Top- level system objectives and scope Operational concept Shared vision and context for stakeholders
LCA
Elaboration of system objectives and scope Critical scenarios described Complete Traceability between capabilities, activities, project goals, levels of service and organization goals.
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OCD Modeling Resources
Electronic Process Guide (EPG) MBASE Deliverables Guidelines Active Template for OCD Best Practices
Examples from previous projects
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Shared Vision and The OCD
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OCD 2. Shared Vision
Provides common basis among stakeholders of understanding as to what the project is and why it is being done Critical to establish early on and maintain throughout A good place to start a project
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OCD 2.1
System Capability Description
A concise description of the system that can pass the "elevator test" Form:
For (target customer) Who (statement of the need or opportunity The (product name) is a (product category) That (statement of key benefit-that is, compelling reaon to buy) Unlike (primary competitive alternative) Our product (statement of primary differentiation)
Here is an example for a corporate order-entry system: "Our sales people need a faster, more integrated order entry system to increase sales. Our proposed Web Order system would give us an e-commerce order entry system similar to Amazon.com's, that will fit the special needs of ordering mobile homes and their aftermarket components. Unlike the template based system our main competitor bought, ours would be faster, more user friendly, and better int egrated with our order fulfillment system.
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2.1.1 Benefits Realized
Describe what the expected benefits to the organization will result from the project Helps avoid "Field of Dreams" syndrome
"Build the field and the players will come" or "Build the software and the benefits will come".
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OCD 2.1.2
Results Chain
A framework linking Initiatives (which consume resources) to Contributions (not delivered systems, but their effects on existing operations) and Outcomes, which may lead either to further contributions or to added value May also identify some additional success-critical stakeholders who need to be represented and "brought into" the shared vision
Implement a new order entry system Increased sales Reduce t...