Online Quiz Flashcards
Systems Engineering
- Top-Down Approach
- Life-Cycle Orientation
- Emphasis and more complete effort to initially define the system requirements
- Interdisciplinary/Team Approach
Top-Down Approach
views the system as a whole
Life-Cycle Orientation
addresses all phases including design, production, distribution, operation, support, etc.
Systems engineering design process should be applied at _________ stage
every
Basic Principles of Functional Analysis
- Problem can be broken down into functions (functional decomposition)
- Problem should be abstracted by considering WHAT before considering HOW
Design parameters are
any factors that affect the design
General Design Process
- Need
- Need Analysis
- Function
- Function Structure
- Functional Requirements
- Performance Requirements
- Conceptual Design
- Preliminary Design
- Final Design
Need Statement
Modified with insight gained from experience developing the function structure
Value of Function Structure
- Aid to the Thought Process
- Display of Overall System
- Identification of Functional Requirements
- Traceability
Means to Identify “Hows”
- Brainstorming alternate ways of HOW to satisfy the requirements
- Parameter Analysis: determine applicable parameters that will affect design at the component level
Down Select Process
- Team proposes criteria
- Team agrees on list of criteria
- Each member uses same criteria and individually fills out the evaluation matrix including:
- weighting factor
- relative merit
- total scores
Traditional engineering design methods are ___________ approach
Bottom-Up Approach
Bottom-Up Approach
Starting with a set of known elements, design engineers create the product or system by a combination of system elements
Systems Engineering Process (Top-Down Approach)
Starting with requirements about the external behavior of any part of the system, analyzed to identify functional characteristics
Characteristics of Top-Down Process
- Process is applicable to any part of the system
2. Process is self-consistent
Differences in Bottom-Up and Top-Down Approaches
- In Bottom-Up, physical realizability in terms on known elements is assured, where as the Top-Down process ends with the system elements as functional entities. Physical Realizability is not guaranteed.
- In Top-Down, requirements are always satisfied through every step because it is an inherent part of the methodology, but in Bottom-Up Approach, the methodology provides no assurance that the requirements are always satisfied
Most projects will employ _____ methodologies
- first, systems engineer (Top-Down) to reduce complexity by decomposing system into functional elements
- then, Bottom-Up design to realize the elements of the entire system
Detail (Final) Design begins with:
configuration and baseline developed during preliminary design
Realization includes the technical activities of:
- describing subsystems, units, assemblies, etc. that make up the system
- preparing specifications and design data for all system components
- Procuring Commercial Off the Shelf items (COTS)
- Developing an engineering model, service test model or a prototype of the system
- Integrating system components and testing the integration to verify compliance with the specified requirements
- Re-designing, re-engineering, and re-testing the system
Lower-Level Specification
- Appropriate design parameters
- Technical performance measures (TPM)
- Associated criteria for characteristics that should be incorporated into the design
Design process evolves through the iterative steps of:
- synthesis
- analysis
- evaluation
Three Possibilities for Designs
- SELECT an item commercially available (COTS) -most cost-effective approach
- MODIFY an existing commercial item
- DESIGN, develop and produce a new or unique item to meet specific requirement
Operational Feasibility
implies that the system will perform as intended in an effective and efficient manner for as long as necessary
Accomplishment of Operational Feasibility requires the proper integration of design related specialties into the total engineering design effort such as:
- reliability
- maintainability
- usability (human factors)
Reliability
- Inherent characteristic of design
- requirements must be addressed in the definition of operational requirements
One of the most significant design parameters requiring attention is _________.
reliability
Definition of Reliability
Probability that something will perform
- in a satisfactory manner
- for a given period
- when used under specified conditions
Design for Reliability Terms
- Probability
- Satisfactory Performance
- Time
- Specified Operating Conditions
