Title: NU CITMOT 601 Systems Engineering
1NU CIT-MOT 601 Systems Engineering
Systems, Life Cycle, and Approaches BRINGING
SYSTEMS INTO BEING
Benjamin S. Blanchard Walter J. Fabrycky,
"System Engineering and Analysis", 4th Ed.
Prentice Hall, 2006
2Engineering for Product Competitiveness
- Products must meet customer expectations
- Systems engineering is to provide systems and
products that meet expectations cost-effectively - Improved methods for defining product and system
requirements - Define systems functionally before physically
- Overall system hierarchy Interrelationships and
Intra-relationships - Integration of engineering and other related
disciplines - Establishing a disciplined approach with
appropriate review, evaluation and feedback
3Motives For Engineering Optimum Systems
- High competition
- Globalization
- Ever demanding customers
- Technology Development
- Great strides in Science, Technology, and tools
- Limited resources
4The System Life Cycle Engineering
- Acquisition phase
- Need
- Conceptual design
- Detailed design
- Production and/ or construction
- Utilization phase
- Delivery/ use
- Support and improvement
- - Phase out/ retirement/ Discard
51 - Conceptual Design
- Feasibility studies are conducted to determine
design parameters - Economic feasibility study
- Market study ---- System boundaries (volume/
quantities), price ranges, competition, life
expectancy, capital/ funding. - Technical feasibility ---- resources availability
(suppliers, capital/ funding, ..), designs, - Feasibility study involves
- Needs analysis
- Functional requirements
- System operational requirements
- System maintenance concept
- Advanced product/ system planning (Plans
Specifications)
62 - Preliminary Design
- System Functional Analysis
- Functional analysis
- System operational functions
- System maintenance functions
- Preliminary Synthesis and Allocation of Design
Criteria - Allocation of performance factors, design
factors, and effectiveness requirements
72 - Preliminary Design
- System Optimization
- System and subsystem trade-offs analysis
- Evaluation of alternatives
- System and subsystem analysis
- System Synthesis and Definition
- Preliminary design, performance metrics,
configuration and arrangement of chosen system
(analyses, data prototyping, physical models,
testing, etc.) - Detailed specification
83 - Detailed Design and Development
- System-Product Design
- Detailed design of functional system (equipment
s/w) - Detailed design of system maintenance and
logistic support elements - Design support functions
- Design data and documentation
- System analysis and evaluation
- Design review
93 - Detailed Design and Development
- System Prototype Development
- Development of system prototype model
- Development of system maintenance and logistic
support requirements - System Prototype Test and Evaluation
- Test preparation
- Testing
- Modification for corrective actions
104 Production and/or Construction
- System assessment, analysis and evaluation
- Modifications for corrective action and/or for
product improvement
115 Utilization and Support
- System assessment, analysis and evaluation
- Continued modification for corrective action or
for product improvement
6 Phase-out and Disposal
12Designing For The Life Cycle
- Considerations
- Acquisition process
- Standards
- Ability to integrate
- user compatibility
- Serviceability/ Support
- ...
- For shorter Development cycle
- Teams
- Concurrent engineering
13System Engineering Definitions
- Systems Engineering
- An interdisciplinary collaborative approach to
derive, evolve, and verify a life cycle balanced
system solution which satisfies customer
expectations and meets public acceptability
14System Engineering Definitions
- Characteristics of Systems Engineering
- Top-down approach that views the system as a
whole - A life Cycle orientation that addresses phases of
system life cycle - Initial definition of system requirements,
relating such requirements to design evaluation
criteria and performance measures - An interdisciplinary or team approach throughout
the system design and development - The use of appropriate technologies and
management principles in a synergetic manner
15The System ProcessLife-Cycle Process and Steps
- Phase
- Conceptual Design
- Preliminary Design
- Detailed Design
- Production
- Operational Use
- Baseline
- System Specification
- Functional allocation
- Design/ Material/ Processes
- Optimize
- Open ended
Figure 2.4 pp 26
16The System ProcessTop-Down and Bottom-Up
Approaches
- Top-Down Approach
- Starts from the systems functional
requirements, (top where system input is known)
and breaking it down into sub-functions
identifying relationships, input, output and
devising requirements (process) for each. - Bottom-Up Approach
- Starts from the output requirement (Bottom),
identifying what does it take for this output to
be realized (functions, input, output), leading
to top, where system input is determined.
17The System ProcessTop-Down and Bottom-Up
Approaches
- Top-Down Approach
- Does not guarantee exactly the required
outcome, however recognizes the need and
limitations all along - Bottom-Up Approach
- May guarantee the outcome, however, does not
recognize limitations at the design stage, which
require iterations. - Best approach is a combination of the two
18The System ProcessFeedback In System Engineering
Process
19The System ProcessOther System Engineering Models
Waterfall Process Model
20The System ProcessOther System Engineering Models
Vee Process Model
21The System ProcessOther System Engineering Models
Spiral Process Model
22System Design Evaluation
- At all stages, it is essential to evaluate
alternative designs - To evaluate is to assess satisfying the
requirements - Requirements analysis establishes the baseline
for evaluation - Design criteria depends on the stage
- Criteria are classified as
- System level criteria
- Sub-system level criteria
- Components level criteria
- ...
23System Design Criteria - Decomposition
24System Design Evaluation
- The technical performance measures (TPMs)
refelect the overall performance of the system - The design-dependent parameters (DDPs) are
identified at subsystem level - Many factors, measures of effectiveness,
trade-offs at all levels to be considered - Follow the design consideration hierarchy (Fig.
2.9 pp 35)
25Design Consideration Hierarchy
26System Design Evaluation
- An iterative, continuous process
27Generating Evaluating Design alternatives
- Morphology for design synthesis, analysis, and
evaluation
28Implementing System Engineering
- Due to the following factors there is an
increased trend in the use of system eng.
Methodology - New technology is being introduced
- Increased customer demands/ needs
- Life cycles are being extended
- Cost increase
- Limited resources
- ..
- The use of strictly bottom-up approach proved
unreliable
29Implementing System Engineering
30Applications of System Engineering
- Large-scale systems with many components.
- Small-scale systems with relatively few
components. - Manufacturing systems.
- Introduction of advanced technologies / new
systems. - System that are highly equipment, software,
facilities, or data intensive. - Systems having several suppliers.
- ... etc
31Management of System Engineering
- System engineering is applicable in all phases of
life cycle - Greatest benefits are derived from emphasis in
early stages
32Management of System Engineering
- Objective is to influence the design in the early
phases of acquisition, effectively and
efficiently - It leads to the identification of the individual
design disciplinary needs proceeding from system
level to subsystem levels - Goal is to ensure that requirements are properly
balanced and integrated - Applicable engineering disciplines responsible
for the design of the individual system elements
to be properly integrated - System engineering first establishes the
requirements then ensure proper integration
throughout the life cycle
33Integration of Disciplines
34Management of System Engineering
- System engineering must be addressed in terms of
both technology and management. - Concurrent Engineering
- Communication
35Potential Benefits of System Engineering
- Reduction in costs along the life cycle
- Reduction in system acquisition time
- More visibility and less risk associated with
design decisions