CC532 Collaborative System Design

Transcription

1 CC532 Collaborative Design Part I: Fundamentals of s Engineering 5. s Thinking, s and Functional Analysis

2 Views External View : showing the system s interaction with environment (users) 2 of 24 Inputs Outputs Internal View Structural View : showing the system or data architecture Behavioural View : showing the behaviour of the system

3 s Thinking 3 of 24 Definition Any process of estimating or inferring how local policies, actions, or changes influences the state of the neighboring universe [Wikipedia Encyclopedia] s thinking is a discipline for seeing wholes, recognizing patterns and interrelationships, and learning how to structure those interrelationships in more effective, efficient ways. [Senge, P. & Lannon-Kim, C., 1991] Objective of s Thinking Learning to see the world systemically Reasoning of Multi-levels + + PARTS? WHOLE

4 s Thinking : Multiple Views of 4 of 24 Abstraction View High Level Decomposition View Low Modularity Composition View High Cohesion Low Coupling Low Level High Modularity Low Cohesion High Coupling

5 Traditional vs. s Thinking 5 of 24 Step 1 Traditional Thinking (Analytic, Reductionistic, Mechanistic Thinking) Decompose Thing Part 1 Part 2 Part N s Thinking (Strategic, atic Thinking) Identify a whole that contains the Thing of interest Thing Containing environment 2 Explain the behavior of each part, separately, in isolation Part 1 Part 2 Part N Explain the behavior of the containing whole Containing environment 3 Aggregate the part behaviors into an explanation of the whole Part 1 Part 2 Part N Thing Explain the behavior of the Thing to be explained in terms of its functions within its containing whole Thing Function 1 Function 2 Function K

6 Diagrams for s Thinking 6 of 24 Spray Diagram Elements Central circle or blob for main topic; Blobs for sub-topics(optional); Words on the lines or at the ends of lines; Branching sets of lines; Title aaa Sub Topic1 bbb Visual Form ccc Main Topic ddd hhh Sub Topic2 ggg eee fff Rich Picture s Map Pictorial symbols; Keywords; Cartoons; Sketches; Symbols; Title Blobs of varying sizes; Words; Title questions accurate relevant records 1 2 aaa bbb 3 4 ccc ddd 4 ccc 3 ddd How used? What use? eee eee 6 fff ggg 5 treasurer 5 Influence Diagram Blobs of varying sizes; Assorted arrows; Words labeling and possibly also labeling arrows; Key for arrows; Title 6 1 bbb ccc ddd 3 4 eee 2 5 aaa fff Multiple Cause Diagram boundary(optional); Phrases; Arrows(which may occasionally be labeled); Title aaa ccc fff bbb ddd eee ggg Causal Loop Diagram Phrases; Arrows labeled with either + or sign; Title aaa ccc - - fff bbb + - ddd - eee + - ggg

7 Example: Causal Loop Diagram 7 of 24 Deficit Spending - - Invest in Capacity - + Tax Rate Tax-able Economy Tax Collected + Increase Lead Time Reduce Free Capacity + Manufacture - - Cash in Manipulating Income Incentive to Avoid Taxes Tax Driven Investing + + Reduce Customer Satisfaction Sell - - Invest in Sales Force [Higher Tax Rates Mean More Taxes Collected] [Business Management]

8 Example: s Map 8 of 24

9 ANSI/EIA-632 s Engineering Process 9 of 24 Process Input Customer Needs / Objectives / s - Mission / Operations - Measures of Effectiveness - Environments - Constraints Technology Base Prior Output Data Program Decision s s from Tailored Standards & Specifications s Analysis Analyze Missions & Environment Identify Functional s Define / Refine Performance & Design Constraint s s Loop Verification Functional Analysis / Allocation s Analysis & Control Decomposition to Lower-Level Functions Allocate Performance & Other limiting s to Lower-Level Functions Define / Refine Functional Interfaces (internal / External) Define / Refine / Integrate Functional Architecture Design Loop Select Preferred Alternatives Trade-off Studies Effectiveness Analysis Risk Management Configuration Management Interface Management Data Management Performance-Based Progress Measurement - SEMS - TPMs - Technical Reviews Synthesis Transform Architectures (Functional to Physical) Define Alternate Product Concepts Define / refine Functional Interfaces (Internal / External) Define Alternative Product & Process Solutions Integrated Decision Database Decision Support Data Functional & Physical Architectures Specifications & Baselines Balanced Solution Process Output ANSI: American National Standards Institute EIA: Electronic Industries Alliance

10 ? 10 of 24 Definition of A singular documented need of what a particular product or service should be or do in a formal sense. [Wikipedia Encyclopedia] A requirement must be: Necessary Specific / Measurable Achievable but implementation free Consistent Analyst Customer Procedure Compatibility Why What How s Analysis Domain Expert (Derived) s Specification (Additional) Design Implementation Expert Developer Designer Document Not Good s Good s Process

11 s Set 11 of 24 User s CR (Cost ) TOR (Trade-Off ) Technology s TR (Technology ) Concept & Capability / Platform s Analysis Functional s FR (Functional ) TR (Test ) PR (Performance ) Sub-system Functional Analysis Derived s Component

12 Engineer s Design 12 of 24 s Set FR (Functional ) TR (Technology ) PR ( Performance ) CR (Cost ) TOR (Trade-Off ) TR (Test ) PR FR TR Functional Design Buildable Design Performance Analysis Cost Analysis Implementable Design C/P Optimization Design For Specialized Engineers CR TOR

13 Performance-oriented Functional Design 13 of 24 PR Efficiency Response time Speed Throughput Latency Accuracy Length of operational life Inputs Outputs Input trajectory Functional (Logical) Design Performance Analysis A set of logical designs satisfying PR Output trajectory Eligibility function IOR

14 Cost-oriented Buildable Design 14 of 24 CR Financial/Time cost of Develop Purchase Prototype Test Operation Maintain Repair Security Hardware Software Bioware Buildable Design Cost Analysis A set of Buildable Designs satisfying CR Humanware TYR

15 Analysis and Specification of s 15 of 24 Focus on: Synchronization, concurrency, and communication Control Oriented Flowchart Focus on: Input/output transformation and flow of process Function/Process Oriented s Analysis and Specification SA(Structured Analysis) SADT(Structured Analysis and Design) VDM(Vienna Design Method) Focus on: Internal state of system Data Oriented JSD(Jackson Development) ER(Entity-relationship Modeling) Object Oriented Focus on: State change of components and their interactions UML (Unified Modeling Language)

16 s Tools 16 of 24 Functional block N x N chart Architecture Functional areas C1 C2 C3 C4 C1 X X C2 X X C3 X X C4 X X Interfaces Relationships Sub-A Sub-B Component1 Component2 Component3 Component4 Data/Control flow Functional/Operational flow Component1 F1 F2 Database Control flows F3 Functions Sequences F4

17 s Primary Life Cycle 17 of 24 Process Identification of Need Development Planning Feasibility Analysis s Analysis User s Technical s Operational s Maintenance and Support s Technical Performance Measures (TPMs) Research Input(Techn ology) and suggestion Functional Analysis Functional Allocation Functional Decomposition s Specification Conceptual Design Review Preliminary Architectural Design

18 s at Different Stakeholders 18 of 24 Customers Specify the requirements and read them to check that they meet their needs. They specify changes to the requirements Interviews and surveys Feasibility studies Use cases and scenarios Introspection Group elicitation Managers Use the requirements document to plan a bid for the system and to plan the system development process Management s Program Planning Control Version Control Engineers Use the requirements to understand what system is to be developed Specification Software Hardware Test Engineers Use the requirements to develop validation tests for the system Test and Support Equipment Test Data Dissemination Integration Reporting Maintenance Engineers Use the requirements to help understand the system and the relationship between its parts Maintenance and Support Planning Maintenance and Support Personnel Training & Training Support Minor Upgrades (components) Major Upgrades (system)

19 s Analysis 19 of 24 Mission statement (programs) Objective statement (projects) boundaries Identified customer set customer needs/wants Feedback s Analysis Collect requirement source documents/information Refine system requirements Analysis of customer needs, requirements and objectives Define projected utilization environments for people, products and processes measure of effectiveness(moe) Customer s Set Technical s Set Design s Specification Review

20 Functional Analysis / Allocation 20 of 24 Functional Analysis the process of translating systems requirements into detailed design criteria Specify whats (not hows ) Abstract and analyze Functions -Decompose Higher Functions Assess the integrity of the functional architecture As system functions are decomposed into functions, interfaces between interacting functions are created Iteratively keep decomposing functions onto a lower-level functions Functional Allocation Allocate - From Higher to Lower Functions Combine or group similar functions into logical subdivisions, identifying major groups Conversion of the whats into hows system broken down into components Trade-offs studies involved implementation approaches involved

21 Bottom-Up vs. Top-Down Design 21 of 24 Bottom-up The designer starts with basic components and synthesizes them to create the overall system Consider designing a car from many parts will the final product meet requirements? Pros: Leads to efficient subsystem Cons: Difficult to meet requirement; Complexity difficult to manage; Difficult redesign Top-down The designer has an overall vision of what the final system must do, and the problem is partitioned into components, or subsystems that work together to achieve the goal Pros: Highly predictable design cycle; Full utilization of requirements; Efficient development of large systems Cons: More time spent in planning; May limit creativity In reality, the designer must alternate between both designs

22 Functional Allocation and Flowdown Allocation s Sub- A Sub- B SYS001 X X 22 of 24 Sub- C SYS002 X X SYS003 X SYS004 X X X SYS005 X Sub- A Sub- B Sub- C SYS006 SYS007 X X X Flowdown Sub- A Sub- B Sub- C SYS001 SSA 001 SSA 002 SSB 001 Component A Component B Component C Component D Component E Component F Component G SYS002 SSA 003 SSA 004 SSA 005 SSC 001 SSC 002 SYS003 SSB 002 SSB 003 SYS004 SSA 006 SSA 007 SSB 004 SSB 005 SSB 006 SSC 003 Sub-Components Hierarchy SYS005 SYS006 SYS007 SSA 008 SSA 009 SSB 007 SSB 008 SSB 009 SSC 004 SSC 005

23 Iteration in Functional Allocation and Flowdown Develop s 23 of 24 Define Hierarchy Traceability Fail Fail Allocate (1 Level) Validate Flowdown (1 Level) Validate Pass Pass Allocate (1 More Level) s SYS001 SYS002 Sub- A SSA001 SSA002 SSA003 Component A CMA001 CMA002 CMA003 Component B CMB001 CMB002 CMB003 Component C CMC001 CMC002 SSA004 CMA004 CMB004 CMC003 SSA005 CMA005 CMB005 CMB006 CMC004 CMC005 Iteration Validate ETC.

24 Example: Audio Amplifier 24 of 24 Audio Amplifier Level-0 s : Amplify the audio input signal and output the amplified audio signal. Level-1 Audio input signal Power, 220 V ac Audio Amplifier Audio Output signal Pre-amplified input signal Amplified signal Audio input signal Input Amplifier High Gain Amplifier Output Stage Audio Output signal Level-2 15V dc Power, 220 V ac Power Supply