# Presentation: 313556

## AP233 Systems Engineering

- A NASA/PDES Inc. Needs Perspective
- as seen by
- Harold P. Frisch

## STEP/SC4 FrameworkNASA Product Life Cycle View

- Slide from STEP Frameworks document

## SYSTEM ENGINEERING PROCESS - IEEE 1220

- Slide from SEDRES  team

## SE PROCESS w.r.t some SE TOOLS

- Slide from SEDRES  team

## AP233Neutral Data Format

- Slide from SEDRES  team

## AP233Current Focus/Capability

- System architecture information model
- Functional hierarchy
- Physical architecture
- Allocations
- System modeling
- Finite State Machines, causal chains, statecharts, ...
- EXCEL spread sheets (e.g. GSFC/JPL’s IMDC, Team_X,  ISAL, Team_I)
- Verification & Validation
- Requirements Capture, Decomposition & Tracking
- PDM, CM, Work Flow, Graphics, ...
- Current work is essential, it appears solid

## AP233 NASA/PDES Needs

- For products within an established product-line
- Unmanned spacecraft, space based science instruments
- Modeling  needs -  Do you agree ? (Workshop answer - No)
- System engineering models bring minimal added value
- Finite state machine, causal chain
- Engineering test & analysis models for domain and cross domain what-if, trade, and anomaly studies of critical importance
- Need SE Interface to/from Engineering support domains
- Record of: Who, what, how, when, assumptions, limitations
- Sufficient information to support reuse/redo decisions

- SE - System Engineering
- EA - Engineering Analysis

## AP233 NASA/PDES Needs

- At SE interface to the engineering support domains enable the  representation and exchange of:
- System Characterization Properties
- Behavior Models (static, quasi-static, dynamic)
- Metadata (who, what, when, how, why, ...)
- Technical Data Packages exchanged at interface
- From SE to Engineering Support Domains and back
- Package has all data & metadata to enable future users to determine if information is reusable for a new need
- Provide for archival/retrieval of Technical Data Packages

## On Property Metadata

- Property -
- an observable or measurable aspect of a
- product, state or activity
- relative to a modeling paradigm that can be used for prediction
- For example,  F=ma implies mass (m) is constant
- Life cycle dependency
- As: required, proposed, built, maintained, operated...
- Need to archive - What, how, who, why, when, ...
- Observation or measurement has method -
- estimation, analysis, test
- Estimation, analysis, test has -
- _x0008_Methodology detail & conditions, measure with units and value

## On Property Metadata

- Measure with units and value may be -
- numeric, Boolean, fuzzy, percentile, probabilistic etc.
- Properties have relationships -
- laws of nature-math-geometry, product design, risk & opportunity, engineering insight, corporate knowledge - these are properties
- Values have measures of precision -
- statistical, fuzzy, bounded - these are properties
- Methodology detail & conditions defines
- How, under what conditions - these are properties

## AP233 Status

- Requirements document ready for final approval by AP233 working group in Melbourne (2/00)
- NASA/PDES needs embedded in requirements document
- EXPRESS & EXPRESS-G models exist, definitions for entities, attributes - some written, more in Melbourne
- NASA need issues being pushed hard; but, consensus required
- SE to EA information exchange interface
- Technical Data Packages (TDP) (AP232 has enabling capability)
- Embedded within TDP’s is property metadata
- EXPRESS expert from NASA/PDES need group required
- Evaluate EXPRESS model and validate that needs are being satisfied
- Support modularization & harmonization