Outline. Concept of Development Stage. Engineering Development Stage. Post Development Stage. Systems Engineering Decision Tool

Transcription

1 Outline Course Outline Introduction to the Course Introduction to Systems Engineering Structure of Complex System System Development Process Needs Analysis Concept Exploration Concept Definition Advanced Development Engineering Design Integration and Evaluation Production Operation and Support Software Systems Engineering Systems Engineering Decision Tool Concept of Development Stage Engineering Development Stage Post Development Stage Systems Engineering Decision Tool 1

2 Needs Analysis Objectives of the need analysis phase are to identify: A valid operational need for a new system A feasible approach to meeting the need A needs-driven system development: Stems from a serious deficiency in current system capabilities Requires a feasible and affordable technical approach Is the characteristicsof mostdefenseand other government programs A technology-driven system development: Stems from a major technological opportunity to better meet a need Requires demonstration of practicality and marketability Is the characteristic of most commercial system developments 2

3 Needs Analysis Phase in system life cycle 3

4 Status of System Materialization at Needs Analysis Phase 4

5 Needs Analysis cont. The needs analysis phase is the first step in the materializationof a new system: from a general operational concept to an engineered system Activities comprising needs analysis are: Operation analysis understanding needs for a new system Functional analysis deriving functions required to accomplish operations Feasibility definition visualizing a feasible implementation approach Needs validation demonstrating cost effectiveness Projected needs should considertechnological growth for entire life of a new system To serve as a basis for system development, operational objectives should be necessary and sufficient 5

6 Needs Analysis Phase Flow Diagram 6

7

8

9

10 Needs Analysis cont. Predecessor systems exist for most new system applications and are: Candidates for major upgrading in place of new systems Useful points of departure for new systems concepts Feasibilityofsatisfyinga projected need must be demonstrated and: At least one credible approach must be visualized System functions to achieve operational objectives must be defined Approach must be described and the cost need to be approximate System operational requirements must be defined and: Validated by operational effectiveness analysis Evaluated with agreed upon measures of effectiveness (MOE) Reflect the entire system life cycle 10

11 Needs Analysis cont. Problems Describe and define the principal outputs (products) of the needs analysis phase. List and define the primary systems engineering activities that contribute to these products. Identify the relationships between operational objectives and functional requirements for the case of new consumer aircraft. Cite three operational objectives and the functional requirements that are needed to realize these objectives. What is meat by measure of effectiveness? For the effectiveness analysis of a sport utility vehicle (SUV), list what you think would be the ten most important characteristics that should be exercised and measured in the analysis. 11

12 Outline Course Outline Introduction to the Course Introduction to Systems Engineering Structure of Complex System System Development Process Needs Analysis Concept Exploration Concept Definition Advanced Development Engineering Design Integration and Evaluation Production Operation and Support Software Systems Engineering Systems Engineering Decision Tool Concept of Development Stage Engineering Development Stage Post Development Stage Systems Engineering Decision Tool 12

13 Concept Exploration Objectives of the concept exploration phase are to: Explore alternatives concepts to derive common characteristics Convert the operationally oriented system view into an engineering-oriented view Outputs of the concept exploration are: System performance requirements System architecture down to the subsystem level Alternative system concepts Activities that comprise concept exploration are: Operational requirements analysis ensuring completeness and consistency Implementation concepts exploration refining functional characteristics Performance requirements formulation deriving functions and parameters Performance requirements validation ensuring operational validity 13

14 Concept Exploration Phase in System Life Cycle 14

15 Status of System Materialization of Concept Exploration Phase 15

16 Concept Exploration Phase Flow Diagram 16

17 Concept Exploration cont. Operational requirements analysis usually involves: Analysis of alternatives concepts Conduct of effectiveness simulations Ensuring that requirements are properly stated Considering interfaces with related systems Prescribing a concept of operations System development is a non-deterministic process in that: It requires an iterative induction reasoning process Many possible solutions can satisfy a set of operational requirements The predecessor system can help define: System functional architecture Performance of functional building blocks 17

18 Concept Exploration cont. Exploration of alternative implementation concepts should: Avoid the Point Design Syndrome Address a broad spectrum of alternatives Consider adaptation of predecessor system technology Consider innovative approaches using advanced technology Assess the performance, risk, cost and growth potential of each alternative Technology development is an important component of system development: Industry and government support major R&D programs The defense industry has IR&D funds for system innovations technical base is the source of many innovative concepts System performance requirements are developed through: Analyses to establish performance parameters of each concept Effectiveness analyses of conformance with operational requirements Careful examination of constraints 18

19 Concept Exploration cont. Constraints are imposed by: System operator, maintenance and test considerations Requirements for interfacing with other systems Externally determined operational environments Fabrication, transportation and storage environments System performance requirements define: What the system should do, but not how it should do it System characteristics in engineering terms Necessary and sufficient set reflecting operational requirements and constraints Performance requirements validation involves two interrelated activities: Integration of requirements derived from alternative system concepts Effectiveness analyses to demonstrate satisfaction of the operational requirements Performance requirements are defined in a living document: Requirements are reviewed and updated throughout the system life cycle 19

20 Concept Exploration cont. Problems Explain why it is necessary to examine a number of alternative system concepts prior to defining a set of system performance requirements for the purpose of competitive system acquisition. What are the likely results of failing to examine a sufficient range of such concepts? To meet future pollution standards several automobile manufacturers are developing cars powered by electricity. Which major components of gasolinepowered automobiles would you expect to be retained with minor changes, which ones would probably be substantially changed, and how and which would be new? (Do not consider components not directly associated with the automobile s primary function, such as entertainment, automatic cruise control, power seats and windows, airbags, etc) List the characteristics of a set of well stated operational requirements, that is, the qualities that you would look for in analyzing their adequacy. For each, state what could be the result if a requirement did not have this characteristic. 20

21 Outline Course Outline Introduction to the Course Introduction to Systems Engineering Structure of Complex System System Development Process Needs Analysis Concept Exploration Concept Definition Advanced Development Engineering Design Integration and Evaluation Production Operation and Support Software Systems Engineering Systems Engineering Decision Tool Concept of Development Stage Engineering Development Stage Post Development Stage Systems Engineering Decision Tool 21

22 Concept Definition Objectives of the concept definition phase are to: Select a preferred system configuration Define the system functional specifications, development schedule and cost Concept definition concludes the concept development stage, which: Lays the basic for the engineering development stage of the system life cycle Provides a baseline for development and engineering Activities that comprise concept definition are: Performance requirement analysis relating to operational objectives Functional analysis and formulation allocating functions to components Concept selection choosing the preferred concept by trade-off analysis Concept validation confirming validity and superiority of the chosen concept 22

23 Concept Definition Phase in System Life Cycle 23

24 Status of System Materialization of Concept Definition Phase 24

25 Concept Definition Phase Flow Diagram 25

26 Concept Definition cont. Performance requirements analysis must include: Compatibility with system operating site and logistic support Reliability, maintainability and support facilities Environmental compatibility The entire life cycle from production to system disposition Functional system building blocks are usefulfor functional definition Selectionof a preferred concept is a systems engineering function, which formulatesand compares evaluationof a range of alternative concepts. 26

27 Integrated definition zero (IDEF0)is the primary technique for representing system functionality

28 Example: Coffee Maker Input Functions Accept user command (on/off) Receive coffee materials Distribute electricity Distribute weight Transformative Functions Heat water Mix hot water with coffee grinds Filter out coffee grinds Warm brewed coffee Output Functions Provide status Facilitate removal of materials Dissipate heat

29 Example: Coffee Maker FBD using 11 functions

30 Concept Definition cont. System concepts are evaluated in terms of: Operational performance and compatibility Program cost and schedule Risks in achieving each of the above Program risk can be considered toconsist of a combination of 2 factors: Likelihood that the system will fail to achieve its objectives Impact of the failureon the success of the program Program risks can result from: Unproven technology Difficult performance requirements Severe environments Inadequate funding or staffing An unduly short schedule 30

31 Concept Definition cont. Trade-offanalysisis fundamentalin all systematic decision making In concept selection trade-off analysis should be: Organized set up as a distinct process Exhaustive consider the full range of alternatives Semi-quantitative use relative weightings of criteria Comprehensive consider all major characteristics Documented describe the results fully Work breakdown structure (WBS) is essentialin a system development, and: Is organized in a hierarchical structure Defines all of the constituent tasks in the program 31

32 Concept Definition cont. The systems engineering management plan (SEMP) definesall systems engineering activities through the system life cycle. Justification for the development of the selected concept should: Show the validityof the needto be met State reasons for selecting the concept over the alternatives Describe program risks and means for containment Give evidence of detailed plans, such as WBS, SEMP Give evidence of previous experience and successes Present life cycle costing Cover other relevant issues such as environmental impact. System functional address: System functional description Required characteristics Support requirements 32

33 Concept Definition cont. Problems Describe three principal differences between system performance requirements, which are an input to the concept definition phase, and system functional specifications which are an output. Both the concept exploration and concept definition phases analyze several alternative system concepts. Explain the principal differences in the objectives of this process in the two phases and in the manner in which the analysis is performed. Describe what is meant by the term functional allocation and illustrate its application to a personal computer. Draw a functional diagram of a personal computer using the functional elements described as building blocks, describe what functions it performs, how it interacts with other building blocks and how it relates to the external inputs and outputs of the computer system. 33