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VV&A-1 The Basics of the M&S VV&A Process Simone Youngblood The Johns Hopkins University Applied Physics Lab
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VV&A-2 Agenda Definitions The VV&A Processes VV&A as Applied to the Simulation Categories Documentation Conclusion
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VV&A-3 Definitions M&S VV&A
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VV&A-4 What is Verification? The process of determining that a model implementation accurately represents the developer's conceptual description and specifications. Provides information about M&S attributes that is used to assess & demonstrate suitability Goal: Did I build it RIGHT?
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VV&A-5 What is Validation? The process of determining the degree to which a model is an accurate representation of the real world from the perspective of the intended uses of the model. Provides information about M&S attributes that is used to assess & demonstrate suitability Goal: Did I build the RIGHT thing?
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VV&A-6 What is Accreditation? The official certification that a model, simulation, or federation of models and simulations and its associated data are acceptable for use for a specific purpose. The certification is based on the accreditation assessment. Goal: Are the results of the M&S FIT FOR PURPOSE and USEFUL for making decisions?
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VV&A-7 The Balancing Act RiskResourcesVV&A Balancing the cost of knowing against the risk of assuming.
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VV&A-8 The VV&A Processes M&S VV&A
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VV&A-9 VV&A and the Problem Solving Process From the RPG
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VV&A-10 Tailoring Guidance: Stay Focused on the Problem Maintain a problem orientation –Understand the relationships between The problem being solved The role of M&S in the problem The role of VV&A in establishing M&S credibility –If the problem is too complex, decompose it into workable units Ensure that you are still trying to solve the same problem Focus on accreditation –Ensure that the V&V evidence is clearly applicable to the intended purpose - solving ‘this’ problem
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VV&A-11 Tailoring Guidance: Understand the Problem Define the explicit problem requirements –What specific questions are to be answered? –What are the MOE’s? –How will M&S be used? –What do the M&S need to do? –How good do the M&S need to be? Define what question(s) need to be answered... –Define what the M&S needs really are –Define the acceptability criteria needed to assess M&S attributes and the specific needs –Identify the M&S choices, the VV&A credibility needs, and the level of development resources ($$$) necessary to meet defined needs An explicit statement of the problem is the most important aspect of cost-effective VV&A and the hardest to come by
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VV&A-12 Tailoring Guidance: Know the Level of Credibility Required Credibility is Defined by the Customer - but it has a cost –Ensure that the right people make the decision on the level of credibility they need –Ensure the Level of Credibility is explicitly defined by the Acceptability Criteria Credibility and Risk Assessment - know the limits & tolerances –How will accepting a bad answer affect the ‘end user’ decision or results –What are the costs in time, equipment and decisions for lower levels of results Tailor Risk Analysis to Level of Credibility Requirements –Determine how much evidence will be needed to accredit M&S –Determine the impact of NOT doing (or failing) V&V –Provide forums to facilitate development of workaround strategies and assessment of these solutions- both positive and negative impacts
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VV&A-13 Tailoring Guidance: Determine How to Optimize Resources Not all V&V supports Accreditation to the same extent –Know what each type of M&S information ‘buys’ you relative to the cost of producing it Try to avoid (re)doing it all yourself –Capitalize on existing VV&A information whenever possible –Know how to extract useful data from software V&V results Cooperative evolution for resources : use common VV&A data elements and report structure –The VV&A Templates provides a common structure for documenting VV&A information –Each of the Services has adopted a common database structure for their M&S Resource Repositories
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VV&A-14 Challenge Issues that Impact VV&A Implementation The lack of a well defined referent Determining how to use and when to use Subject Matter Experts The lack of insight into the M&S The lack of M&S stability Starting the V&V/A process “late” Keeping the second “V” in V&V
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VV&A-15 VV&A as Applied to the Simulation Categories M&S VV&A
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VV&A-16 Simulation Categories New M&S Development Any stand-alone model or simulation under development being built to address the intended purpose or purposes of the User. Legacy Any model or simulation that was developed either in the past or for a different purpose. Federation A system of interacting models and/or simulations, with supporting infrastructure, based on a common understanding of the objects portrayed in the system.
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VV&A-17 VV&A and New M&S Development ACCREDITATION PROCESS PROBLEM SOLVING PROCESS Establish Objectives Define Problem Accept & Record Solution Analyze Results Non-M&S Methods M&S USE PROCESS Select Approaches Select Approaches Apply Results Apply Results Repository Execute and Prepare Results yes no Make Accreditation Decision Develop New M&S Define M&S Rqmts Plan Approach M&S Method M&S DEVELOPMENT/PREPARATION PROCESS Refine M&S Rqmts Plan M&S Develop -ment Develop Con- ceptual Model Imple- ment & Test Develop Design Collect and Evaluate Accreditation Information Perform Accreditatio n Assessment Perform Accreditatio n Assessment Develop Accreditation Plan V&V PROCESS Verify Design Validate Concep -tual Model Verify Imple- ment- ation Validate Results Verify Rqmts Develop V&V Plan Prepare M&S for Use
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VV&A-18 VV&A and Legacy M&S Is There Sufficient Info to Assess the M&S? NO Refine Rqmts and Verify Obtain Needed Information and Verify NO YES NO Plan/Conduct Accreditation Assessment Plan M&S Modification Modify and Verify Use As-Is Use As-Is or Modify? Reject M&S Are the Requirements Adequate? YES Validate Prepare M&S for Use Issue Accreditation Decision AA User AA Define Requirements User AA Select Legacy M&S AA VV AA VV User Prop User AA, VV VV User Prop User, Dev, VV Prop Dev VV, Prop Is the Info on M&S Capability Adequate? Can the M&S be Used? Modify V&V as Needed VV NO YES Prop, Dev AA, VV [ AA ]Accreditation Agent[ User ]User [ Dev ]Developer[ VV ]V&V Agent [ Prop ]M&S Proponent [ AA ]Accreditation Agent[ User ]User [ Dev ]Developer[ VV ]V&V Agent [ Prop ]M&S Proponent
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VV&A-19 Advantages of Using Legacy M&S Starting with a legacy simulation may be more expedient, requiring less time and fewer resources than a new development The experience of previous developers and users may be leveraged to establish a knowledge base that can provide guidance and support training Testing and VV&A histories can provide evidence of simulation capabilities and limitations allowing the current effort to focus on high risk areas A legacy simulation with a good reputation for providing credible results in similar applications can increase the simulation’s credibility (i.e., the User’s confidence in the simulation’s ability to address the current situation) due to –the demonstrated ability to address similar requirements –the demonstrated capabilities of the existing simulation –the direct experiences of previous users who successfully applied the simulation to related problems
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VV&A-20 Disadvantages of Using Legacy M&S The simulation was developed to address different requirements Unexpected and undesirable side effects may occur during execution of the code The simulation comes with specific hardware and software, which may be obsolete The simulation comes with specific data needs, however the data to fulfill those needs may no longer be authoritative or available Information about the simulation and its previous usage may be incomplete or inconsistent Participants (e.g., Accreditation Agent, V&V Agent) may need time up front to acquire knowledge about the simulation
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VV&A-21 What Can Help Reduce Legacy V&V Cost Documentation that can directly support the accreditation assessment can reduce the burden of an extensive discovery effort Documentation that completely and accurately describes simulation capabilities and use history can reduce the discovery and training costs A simulation under configuration control with an established user community that can provide necessary information can reduce the support and discovery costs Participants familiar with the simulation can reduce the need for extensive training
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VV&A-22 Scope of the Distributed M&S Problem
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VV&A-23 Distributed M&S: Technical Interoperability From “HLA and Beyond: Interoperability Challenges” by Dahmann, Salisbury, Barry, Turrell, and Blemberg (99F-SIW-073) Characterized by the ability of federates to physically connect and exchange data in accordance with the Federation Object Model (FOM) Involves the use of common standards, compatible interfaces and coordinated data structures Elements of technical interoperability –Hardware compatibility –Standards compatibility –Time management coordination –Coordinated use of Run Time Infrastructure (RTI) services –Security issues
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VV&A-24 Distributed M&S: Substantive Interoperability The capability of federates, when connected, to provide adequate, accurate & consistent simulated representations that adhere to the principles of “fair fight” & address the mission objectives. “HLA supports the technical interoperability between distributed simulations. Substantive interoperability, on the other hand, remains a key challenge to achieving complete distributed simulation interoperability.” [Dahmann et al.]
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VV&A-25 Distributed M&S: Substantive Interoperability Issues Logical interaction between entities modeled in different federates Temporal resolution Spatial resolution Coherent relationships between the components of the physical environment: ground, ocean, atmosphere, weather, infrared, and electromagnetic
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VV&A-26 Documentation M&S VV&A
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VV&A-27 Documentation Philosophy Organize information according to a standard outline –Rationale Eases the comparison of data with accreditation requirements Facilitates V&V data accumulation for future use Reduces costs of multiple accreditations over time –Specific outlines vary with type of data element Structure V&V results to facilitate comparison with M&S requirements –Include description of how the results impact m&s use –State newly discovered discrepancies as assumptions, limitations on model use, or as errors –Identify the range of applicability for all results Particularly regarding any limitations or errors –Ensure results are linked to the applicable M&S version Configuration Management
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VV&A-28 MIL-STD 3022 VV&A Documentation Templates Accreditation PlanV&V PlanV&V ReportAccreditation Report Executive Summary 1 Problem Statement 2 M&S Requirements and Acceptability Criteria 3 M&S Assumptions, Capabilities, Limitations & Risks/Impacts 4 Accreditation Methodology 4 V&V Methodology4 V&V Task Analysis4 Accreditation Assessment 5 Accreditation Issues5 V&V Issues5 V&V Recommendations5 Accreditation Recommendations 6 Key Participants 7 Planned Accreditation Resources 7 Planned V&V Resources7 Actual V&V Resources7 Actual Accreditation Resources 8 V&V Lessons Learned8 Accreditation Lessons Learned Suggested Appendices: A M&S Description B M&S Requirements Traceability Matrix C Basis of Comparison D References E Acronyms F Glossary G Accreditation Programmatics H Distribution List Suggested Appendices: A M&S Description B M&S Requirements Traceability Matrix C Basis of Comparison D References E Acronyms F Glossary G V&V Programmatics H Distribution List I Accreditation Plan Suggested Appendices: A M&S Description B M&S Requirements Traceability Matrix C Basis of Comparison D References E Acronyms F Glossary G V&V Programmatics H Distribution List I V&V Plan J Test Information Suggested Appendices: A M&S Description B M&S Requirements Traceability Matrix C Basis of Comparison D References E Acronyms F Glossary G Accreditation Programmatics H Distribution List I Accreditation Plan J V&V Report
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VV&A-29 VV&A Data Archiving VV&A Documents –Should be archived in central location: Defense Department level or Program level –Indexed in a electronic database –Possibly available on-line Electronic Database –Should contain summarized, unclassified data from VV&A reports –Should be sufficient for model comparisons and selection VV&A data are only useful if they are documented, and the documentation is readily available to model users.
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VV&A-30 Conclusion M&S VV&A
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VV&A-31 Summary of VV&A Cost-effective accreditation requires –Complete problem definition –Clear application description –Explicit statements of M&S requirements and acceptability criteria –A well-planned, tailored and focused accreditation assessment effort Efficient V&V to support accreditation requires –A clearly defined application context to permit focused V&V efforts –The use of risk to focus and tailor the V&V effort –A clear understanding of how each V&V activity contributes to M&S credibility –A means of extracting key accreditation support information from previous V&V (and other M&S) efforts –An efficient means to produce, document, and archive all V&V information (from software and M&S V&V)
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VV&A-32 Simone Youngblood Simone.Youngblood@jhuapl.edu (240) 228-7958 M&S VV&A
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