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 Advanced Development The objectives of the advanced development phase are to: Resolve the majority of uncertainties(risks) through analysis and development Validate the system design approach as a basis for full-scale engineering The outputs of advanced development are: System design specification A validated development model Advanced development is especially critical for systems: Containing extensive advanced development or unproven concepts That may involve several years of development effort Activities encompassed by advanced development are: Requirements analysis relating functional requirements to needs Functional analysis and design identifying performance issues Prototype development building and testing prototypes of critical components Test and evaluation validating maturity of critical components 2

3 Advanced Development cont.. 3

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6 Advanced Development cont.. Analysis of system functional specification is required to relate them to: Their origin in operational requirements. Especially those not readily met their differences from those of a predecessor system Components that may require further developments include those that: Implement a new function Are a new implementation of an existing function Use a new production method for an existing type of component Extend the function of a proven component Involve complex functions, interfaces and interactions Program risks requiring development may result from: Unusually high performance requirements New materials and processes Extreme environmental conditions Complex component interfaces New software elements 6

7 Advanced Development cont.. 7

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10 Advanced Development cont.. Validating testing to confirm resolution of risks requires: Development of a formal test plan(test and evaluation master plan, TEMP) Development of a test equipment Conduct of validation tests Analysis and evaluation of test results Correction of design deficiencies Special test equipment and facilities often represent a major investment Test failures may seriously endanger the program unless quickly diagnosed and rectified Early experimental exploration of interface design is essential Models of systems and components are used extensively in system development 10

11 Advanced Development cont.. 11

12 Advanced Development cont.. Simulations are increasingly important in all stages of development and are: Essential in the analysis of dynamic systems and software Require development and a staff of analysis and operators Development facilities are installations simulating environmental conditions and: Are used for development tests and component evaluation Represent major investment and require a permanent operating staff Risk assessment is a basic engineering tool, which: Is used throughout development, but especially during advanced development Involves identifying sources of risk, risk likelihood and criticality 12

13 Advanced Development Problems The systems engineering method applies to the advanced development phase in a similar set of four steps, as it does to the preceding concept definition phase. For each step in the method compare the activities in the two places with one another, stating in your own words (a) how they are similar and (b) how they are different. What specific activities in the advanced development phase sometimes cause it to be referred to as a risk reduction phase? Give an example of each activity considering a real or hypothetical system. Why do so many new complex system developments incur large risks by choosing to apply immature technology? Give an example of where and how suchchoicespaidoffandonewheretheydidnot. In the development of a major upgrade to a terminal air traffic control systems, what would you except to be three significant risks and what systems engineering approaches would you recommend to mitigate each of these risks (consider problems of failing to meet schedule as well as safety problems) 13

14 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 14

15 Engineering Design The objectives of the engineering design phase are to: Design system components to performance, cost and schedule requirements Establish consistent internal and external interfaces Engineering design culminates in materialization of components of a new system: focused on the final design of the system building blocks Activities constituting engineering design are: Requirements analysis identifying all interfaces and interactions Functional analysis and design focusing on modular configuration Component design designing and prototyping all components Design validation testing and evaluating system components 15

16 Engineering Design Phase in System Life Cycle 16

17 Engineering Design Phase in System Life Cycle 17

18 Status of System Materialization at Engineering Design Phase 18

19 Engineering Design Phase Flow Diagram 19

20 Engineering Design - cont External system interface requirements are specially important at this point in development User interfaces and environmental interactions require particular attention Functional design stresses 3 areas: Modular configuration simplified interactions Software design modular architecture User interfaces effective human interaction Modular partitioning groups tightly bound functions together, into loosely bound modules Object oriented analysis and design are important methods of software system design 20

21 Engineering Design - cont Major defense and space systems engineering is performed in two steps: Engineering design process is focused on configuration items (CIs): these are substantially equivalent to components Preliminary design review(pdr) centers on: Major interfaces, risk areas, long-lead items and system level trade studies Detailed design has the objective to produce a complete description of the end items(cis) constituting the total system. The critical design review (CDR) examines drawings, plans for soundness and adequacy 21

22 Engineering Design - cont Computer-aided design(cad) has revolutionized hardware implementation: Mechanical component design can be analyzed and designed in software Digital electronic is miniaturized, standardized and does not need bread boarding The Boeing 777 development illustrates the power of automated engineering. Reliability must be designed in at the component level: Interfaces, environment and workmanship are vulnerable areas Software must be built to exacting standards and prototyped Extreme reliability is achievable by redundancy Mean time between failure(mtbf) is use as a measure of reliability Maintainability requires rapid fault detection diagnosis and repair: Mean time to repair/restore(mttr) is used as a measure of maintainability Built-in test equipment(bite) is used to detect and diagnose faults Availability measures the probability of the system being ready when called in: availability increases with MTBF and decreases with MTTR. 22

23 Engineering Design - cont Producibility measures the ease of production of system components and benefits from use of commercial components, digital circuitry and broad tolerances Test planning must be done early: Test equipment requires extensive time to design and build Test costs must be provided Test planning is a team effort Development testing is part of the design process: Should start accumulating reliability statistics Test failures are often due to test equipment or procedures Changes after CDR are subject to formal configuration management 23

24 Engineering Design - cont Qualification testing validates component release to integration Configuration management is a systems engineering process that maintain continuity and integrity of system design Configuration baselines defined in major system developments include: Functional baseline system functional specifications Allocation baseline system development specifications Product baseline product, process and materials specifications The configuration item(ci) is a system element: Used to describe and formally control system design Usually corresponding to a component 24

25 Engineering Design cont Problems In spite of the effort devoted to develop critical system components during advanced development, unknownsunknowns can be expressed to appear during engineering design. Discuss what contingency actions a system engineer should take in anticipation of these unk-unks. Your answer should include the consideration of the potential impact on cost, schedule, personnel assignments and test procedures. If you have knowledge of a real life example fromyourwork,youmayusethatasthebasisforyourdiscussion. External system interfaces are especially important during engineering design. Using the design of a new subway system as an example, list six types of external interfaces that will require critical attention. Explain your answer. 25

26 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 26

27 Integration and Evaluation The objectives of the integration and evaluation phase are to: Integrate the engineered components of a new system into an operating whole Demonstrate that the system meets all its operational requirements The outputs of the integration and evaluation phase are: Validated production designs and specifications Qualification for production and subsequent operational use The activities constituting integration and evaluation are: Test planning defining test issues, test scenarios and test equipment System integration integrating components into subsystems and the total system Developmental system testing verifying that the system meets operational requirements Operational test and evaluation validating that the system meets operational requirements 27

28 Integration and Evaluation Phase in System Life Cycle 28

29 Integration and Evaluation Phase in relation to Engineering Design 29

30 System Test and Evaluation Team 30

31 Status of System Materialization at Integration and Evaluation Phase 31

32 System Integration and Evaluation Process 32

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34 System Element Test Configuration 34

35 SubSystem Test Configuration 35

36 Operational testing of an airliner 36

37 Test realism vs cost 37

38 Integration and Evaluation cont. Integration and evaluation materializes the system as a whole and: Synthesizes a functioning total system from individual components Solves any remaining interface and interaction problems Defense systems require a formal test and evaluation master plan (TEMP) which covers test and evaluation planning throughout system development System requirements should be reviewed prior to preparing test plans to allow for: Customer requirements changing during system development Late injection of technology advances, posing risks Key issues during system integration and evaluation include: Intense management scrutiny during system testing Changes in test schedules and funding due to development overruns Readiness of test equipment and facilities 38

39 Integration and Evaluation cont. System test equipment must meet exacting standards and: Accuracy must be much more precise than component tolerances Reliability must be high to avoid aborted tests Design must accommodate multiple use and failure diagnosis A typical test configuration consists of: The system element(component or subsystem) under test A physical or computer model of the component or subsystem An input generator that provides test stimuli An output analyzer that measures element test responses Control and performance analysis units Subsystem integration should be organized to: Minimize special component test generators Build on results of prior test Monitor internal test points for fault diagnosis 39

40 Integration and Evaluation cont. Test failures are often not due to component deficiencies, but: Test equipment may be inadequate Interface specifications may be misinterpreted Interfaces tolerances may be mismatched Integration test facilities are essential to the engineering of complex systems and inadequacies test plans, training or procedures may lead to personnel errors Developmental system testing has the objectives of: Verifying that the system satisfies all its specifications Obtaining evidences concerning its capability to meet operational requirements The system test environment should be realistic as practicable: All external inputs should be real or simulated Conditions expected in operational evaluation should be anticipated Effects impractical to reproduce should be exercised by special tests The entire system life cycle should be considered 40

41 Integration and Evaluation cont. Test events must be carefully planned: Related test objectives should be combined to save time Detailed test scenarios should be prepared Flexibility should be provided to react to unexpected test results A predictive system performance model must be developed: This is a major task requiring systems engineering leadership and effort An engineering development model is excellent for this purpose Developmental tests are carried out by a coordinated team consisting of: Systems engineer who define test requirements and evaluation criteria Test engineers who conduct test and data analysis Design engineers who design test equipment and correct design discrepancies 41

42 Integration and Evaluation cont. System performance discrepancies during developmental testing must be: Provided for in test scheduling Quickly responded to by a remedial plan of action System operational test and evaluation has the objectives of: Validating that the system design satisfies its operational requirements Qualifying the system for production and subsequent operational use Typical high priority operational test issues are: New features designed to eliminate deficiencies in a predecessor system Susceptibilities to severe operational environments Interoperability with interfacing external equipment User system control interfaces 42

43 Integration and Evaluation cont. Essential features of effective operational evaluation include: Familiarity of customer s or customer agent s test personnel with the system Extensive preparation and observation of developmental testing Test scenarios making effective use of facilities and test results Clear and specific test procedures and detailed analysis plans Thorough training of test operation and analysis personnel Fully instrumented test facilities replicating the operational environment Complete support of test consumables, spare parts, manual, etc Accurate data acquisition for diagnostic purposes Special attention to human-machine interfaces Complete provisions for safety of test personnel and neighbouring inhabitants Technical support by system development staff Timely and accurate test reports 43

44 Integration and Evaluation cont. Problems A group of design engineers, test engineers and systems engineers are working together to implement a project. In addition to differences of responsibilities, these classes of individuals typically approach their tasks with significantly different points of view and objectives. Discuss these differences and emphasize the essential role that systems engineers play in coordinating the total effort. 44