1. Chapter 7: The 30 elements of systems engineering
ISE 443 / ETM 543
Fall 2013

2. 7.1 Overview Architecture and construction of systems.
Systems approach …
7 key features
See pg. 193
3 key aspects
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3. 7.2 SE perspectives 2 representations of SE perspectives
Mil-Std-499B Revisited
Broader view of interrelated systems
4 main features to systems engineering
Variety of inputs and outputs exist
NASA mission design process
Built in 3 phases:
Conceptual design
Mission analysis
Definition process
Focuses attention on mission analysis (often overlooked)
Focuses on front end of system life cycle
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4. elements
Inclusive activities that are necessary over the system life cycle
See Exhibit 7.1, pg. 199
See also figs. 7.2 & 7.3, pp
It is important that the CSE master each element and also understand the interrelationship between elements.

5. 7.3.1 Needs, Goals, & Objectives
The same as the first element of the project plan.
Given by the system user and must be current and appropriately stated.

6. 7.3.2 Mission engineering
Detailed articulation and analysis of the intended mission of the system that is being engineered.
Main purposes are to verify that the system has legitimate missions to be executed that are not being carried out by other systems and to provide a technical basis for the full definition of requirements for the system.

7. 7.3.3 Requirements analysis & allocation
Set of activities that review existing requirements, derive new requirements, and then allocate requirements to functional elements of the system.
Can determine ultimate success or failure of the system.

8. 7.3.4 Functional analysis and decomposition
Separate the “what is to be done” from the “how it is to be done”
Includes defining top level functions, decomposing low level functions and subfunctions, allocating data flow appropriately.
Cause the CSE to consider alternative ways to implement a given function.

9. 7.3.5 Architecture design and synthesis
Formulating alternative system architectures and then evaluating them for system requirements satisfaction.
Can involve various technologies and concurrent engineering considerations.
Concurrent engineering is considered as one of the 30 key elements of SE.
Does not include selection of a preferred architecture.

10. 7.3.6 Alternatives analysis and evaluation
Decides the preferred system architecture.
It can use TPM, LCC, risk analysis, ILS, and RMA, etc.
Not enough to simply select the architecture, but also must explain why the architecture was selected.

11. 7.3.7 Technical Performance Measurement
Underlying basis for evaluating the performance of the architecture alternatives.
Key ingredient in selecting more detailed design parameters.
TPP – additional measures represented by the parameters upon which the TPM are dependent.
Load is a special consideration
Often involves computer simulation and models.

12. 7.3.8 Life cycle costing 3 main categories of cost
RDT&E
Acquisition or procurement
O&M
Evaluate a system using a LCC model
Looks at the cost elements of the system
Years of useful life of the overall system and subsystems
Utilize various CERs to develop the necessary cost estimates
Example – COCOMO

13. 7.3.9 Risk analysis Main categories
Schedule
Cost
Performance
Societal
Most difficult is performance because it leads to both scheduling and cost risks
Each risk is evaluated and given a probability level of occurrence and consequence
Societal risk is risk to public that can result from deployment of the system.

14. 7.3.10 Concurrent engineering
Concurrent Engineering is ‘a systematic approach to the integrated, concurrent design of products and their related processes, including manufacturing and support’, and essentially attempts to involve all parties with a role to play throughout the system life cycle. (Justin Blount)
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15. 7.3.11 Specification development
Specification Development is used to continue the design after system architecture selection. It usually involves three categories: hardware, software, and human. (Justin Blount)
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16. 7.3.12 Hardware, software, and human engineering
This element refers to the design and construction of subsystems as well as the components that make up these subsystems. (Ryan Stapleton)
(there’s more to it than this … the challenge to the class is to find at least 1 more thing to say …)
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