ENGI 5708 Design of Civil Engineering Systems

Transcription

1 ENGI 5708 Design of Civil Engineering Systems Lecture 02: Overview of Systems Engineering Shawn Kenny, Ph.D., P.Eng. Assistant Professor Faculty of Engineering and Applied Science Memorial University of Newfoundland

2 Lecture 02 Objective To provide an overview of systems engineering S. Kenny, Ph.D., P.Eng. ENGI 5708 Civil Engineering Systems Lecture 02

3 Systems Engineering is an interdisciplinary approach that encompasses the entire technical effort, and evolves into and verifies an integrated and life cycle balanced set of system people, products, and process solutions that satisfy customer needs. Ref: EIA (1994) S. Kenny, Ph.D., P.Eng. ENGI 5708 Civil Engineering Systems Lecture 02

4 Systems Engineering is an interdisciplinary approach and means to enable the realization of successful systems. It focuses on defining customer needs and required functionality early in the development cycle, documenting requirements, then proceeding with design synthesis and system validation while considering the complete problem: Operations, Cost & Schedule Performance, Training & Support, Test, Disposal and Manufacturing Systems Engineering integrates all the disciplines and specialty groups into a team effort forming a structured development process that proceeds from concept to production to operation. Systems Engineering considers both the business and the technical needs of all customers with the goal of providing a quality product that meets the user needs. Ref: INCOSE (2007) S. Kenny, Ph.D., P.Eng. ENGI 5708 Civil Engineering Systems Lecture 02

5 Systems Engineering is an integrated, quantitative and objective interdisciplinary engineering framework to support decision making processes by establishing optimal solutions to complex problems that satisfy business and technical performance requirements over the life-cycle S. Kenny, Ph.D., P.Eng. ENGI 5708 Civil Engineering Systems Lecture 02

6 Systems Engineering Framework Planning / Development Phasing Systems Engineering Technical Processes Systems Engineering Management Processes Life Cycle Integration S. Kenny, Ph.D., P.Eng. ENGI 5708 Civil Engineering Systems Lecture 02

7 Knowledge Integration Communications Mathematics Complementary Studies Engineering Analysis Engineering Design Systems Engineering Technical Processes Engineering Science S. Kenny, Ph.D., P.Eng. ENGI 5708 Civil Engineering Systems Lecture 02

8 Systems Engineering Applications Civil Engineering Transportation Civil and energy pipeline systems Electrical utilities and telecommunications Water resource management Agriculture and forestry Construction industry S. Kenny, Ph.D., P.Eng. ENGI 5708 Civil Engineering Systems Lecture 02

9 Systems Engineering Applications (cont.) Business Finance Operations management Human resources Marketing Production and Manufacturing Biological and Physical Sciences Military S. Kenny, Ph.D., P.Eng. ENGI 5708 Civil Engineering Systems Lecture 02

10 Systems Engineering Applications (cont.) S. Kenny, Ph.D., P.Eng. ENGI 5708 Civil Engineering Systems Lecture 02

11 Systems Engineering Applications (cont.) S. Kenny, Ph.D., P.Eng. ENGI 5708 Civil Engineering Systems Lecture 02

12 Systems Engineering Lessons Learned History Planning 1968; Delivery 1971 Cost $38 million Systems Approach Integrated working models Human factors unit Design and subsystems integration unit Deployment mechanism, vibration and qualification test units Astronaut trainer Lunar Roving Vehicle Client (NASA astronauts) participation through system life-cycle Lesson Successful project due to applied system engineering management processes and principles Performed all functions reliably with no major anomalies S. Kenny, Ph.D., P.Eng. ENGI 5708 Civil Engineering Systems Lecture 02

13 Systems Engineering Lessons Learned History Planning 1980 s; Launch 1990 Cost $1.5 billion Problem Main mirror spherical aberration Cause Faulty QC during manufacturing Requirement was specified but not properly tested or controlled Device assumed to work correctly Hubble Telescope Lessons Learned Repair in space $50million Conduct appropriate tests on component and system level FAT and SIT S. Kenny, Ph.D., P.Eng. ENGI 5708 Civil Engineering Systems Lecture 02

14 Systems Engineering Approach Problem Definition Generation of Alternatives Model Formulation Evaluation of Alternatives Implementation Data Gathering S. Kenny, Ph.D., P.Eng. ENGI 5708 Civil Engineering Systems Lecture 02

15 Problem Definition Probably Most Critical Systems Phase Get it right the first time Analogue: Free-body diagram Potential negative impact Ineffective use of resources Cascading effect on systems approach Eliminate alternatives Uninformed or incorrect decision making S. Kenny, Ph.D., P.Eng. ENGI 5708 Civil Engineering Systems Lecture 02

16 Problem Definition (cont.) Key Elements Problem statement Objective statement Evaluation criteria S. Kenny, Ph.D., P.Eng. ENGI 5708 Civil Engineering Systems Lecture 02

17 Problem Definition (cont.) Problem Statement System Environment Characterization Engineer Client Systems hierarchy Systems interrelationship Work scope Qualitative and quantitative elements S. Kenny, Ph.D., P.Eng. ENGI 5708 Civil Engineering Systems Lecture 02

18 Problem Definition (cont.) Problem Statement Clear and concise Focus on issues, root cause Expansive, options Tied to work scope Avoid Ambiguity Symptoms focus Narrow view point Preconceptions S. Kenny, Ph.D., P.Eng. ENGI 5708 Civil Engineering Systems Lecture 02

19 Problem Definition (cont.) Problem Statement Address root cause not symptoms Symptom High accident rate at an intersection Potential root cause Traffic volume exceeds capacity Inadequate line of sight Poor alignment or grade Ineffective control systems Driver inattention Weather Combination S. Kenny, Ph.D., P.Eng. ENGI 5708 Civil Engineering Systems Lecture 02

20 Problem Definition (cont.) Objective Statement Decisions to be made Essential variables Parameters Influence decision variables Fixed, uncertainty Constraints Decision variable parameter relationship Natural, physical or practical bound limits Capacity, legal, economic, political, social, moral, ethical Concerned with optimization Exceptions Goal seek problem Multiple objective functions S. Kenny, Ph.D., P.Eng. ENGI 5708 Civil Engineering Systems Lecture 02

21 Problem Definition (cont.) Objective Statement Multiple Objectives Characteristic of most complex systems May appear to be in conflict or mutually exclusive Course focus on single objective problems Production Facility Example Objectives Maximize profits Minimize O&M costs Minimize waste discharge Possible objective statement Maximize profits subject to environmental and waste discharge regulations Remaining objectives become constraints S. Kenny, Ph.D., P.Eng. ENGI 5708 Civil Engineering Systems Lecture 02

22 Problem Definition (cont.) Evaluation Criteria Measure of performance or effectiveness Rational and objective basis to facilitate decision making Quantitative or qualitative Ex: Money/time/quantity, aesthetics, perception Absolute or relative Ex: Profit/loss, product unit cost, benefit/cost ratio S. Kenny, Ph.D., P.Eng. ENGI 5708 Civil Engineering Systems Lecture 02

23 Problem Definition (cont.) Range of Stakeholders Societal engagement Inherent nature with major civil engineering projects Varying concerns, viewpoints and values # problems & solutions system complexity S. Kenny, Ph.D., P.Eng. ENGI 5708 Civil Engineering Systems Lecture 02

24 Generation of Alternatives Brainstorming Keep problem and objective statement in focus Quantity but no prolonged diversion Lateral thinking and unorthodox ideas Avoid criticism Filter and improve alternatives Best Practices and Lessons Learned S. Kenny, Ph.D., P.Eng. ENGI 5708 Civil Engineering Systems Lecture 02

25 Model Formulation Transform Problem Definition Qualitative quantitative Objective framework Parametric sensitivity analysis Mathematical Models Descriptive Prescriptive S. Kenny, Ph.D., P.Eng. ENGI 5708 Civil Engineering Systems Lecture 02

26 Model Formulation (cont.) Caveats Understand theoretical basis Linear, nonlinear Idealizations and limitations Appropriate use and application Deterministic, stochastic process Calibration and validation Quantifiable fact or importance Uncertain or unknown quantities Qualitative limits or thresholds Ex: Land use, noise, aesthetics S. Kenny, Ph.D., P.Eng. ENGI 5708 Civil Engineering Systems Lecture 02

27 Model Formulation (cont.) Descriptive Models Classical engineering models Input and initial condition output Differential equations Finite difference equations Decision making rests with the modeler S. Kenny, Ph.D., P.Eng. ENGI 5708 Civil Engineering Systems Lecture 02

28 Model Formulation (cont.) Prescriptive Models Determine optimal decision or strategy Main focus of systems engineering Problem definition reformulated in mathematical terms Range of mathematical and engineering tools S. Kenny, Ph.D., P.Eng. ENGI 5708 Civil Engineering Systems Lecture 02

29 Model Formulation (cont.) Types of Prescriptive Models Mathematical Programming Variational Methods Analytical Methods Calculus of Variations Linear Programming Dynamic Programming Integer Programming (Continuous) Geometric Programming Maximum Principle Quadratic Programming (Continuous) Convex Programming Dynamic Programming (Discrete) Nonlinear Programming or Multivariable Search Methods Separable Programming Goal Programming or Multicriterion Optimization Combinatorial Programming Maximum Principle (Discrete) Heuristic Programming Ref: Pike (2001) S. Kenny, Ph.D., P.Eng. ENGI 5708 Civil Engineering Systems Lecture 02

30 Model Formulation (cont.) Systems Analysis Techniques Course focus Graphical solutions Linear programming Network analysis Decision theory Resource management tools Economic analysis S. Kenny, Ph.D., P.Eng. ENGI 5708 Civil Engineering Systems Lecture 02

31 Evaluation of Alternatives Systems Analysis Outcome Minimize or maximize objective function Establish single or alternate optimal solutions Informed Decision Basis Evaluation or performance criteria Objective (quantitative) Subjective (aesthetic, political) S. Kenny, Ph.D., P.Eng. ENGI 5708 Civil Engineering Systems Lecture 02

32 Evaluation of Alternatives (cont.) Options Status quo No action or do nothing alternative Reject optimal solution(s) Diverse opinion, no consensus open ended problem May restart systems engineering cycle Select non-optimal solution Subjectivity, external factors Select optimal solution Sensitivity analysis Investigate What if scenarios and variability S. Kenny, Ph.D., P.Eng. ENGI 5708 Civil Engineering Systems Lecture 02

33 Implementation Final Stage On-track with problem definition Tangible results Client engagement Minimal feedback May be dynamic due to variability with time or uncertainty Engineering reporting Technical and non-technical Conclusions and recommendation within systems context S. Kenny, Ph.D., P.Eng. ENGI 5708 Civil Engineering Systems Lecture 02

34 ReVelle et al., (2004) Relevant Chapters Ch. 1 Explaining Systems Analysis Section 1A through 1E Ch. 2 Models in Civil and Environmental Engineering Section 2A through 2C S. Kenny, Ph.D., P.Eng. ENGI 5708 Civil Engineering Systems Lecture 02

35 References EIA (1994). EIA Standard IS-632, Systems Engineering. INCOSE (2007). Wikipedia (2007). Pike, R.W. (2001). Optimization for Engineering Systems. Professor of Chemical Engineering and Systems Science, Louisiana State University ReVelle, C.S., E.E. Whitlatch, Jr. and J.R. Wright (2004). Civil and Environmental Systems Engineering 2 nd Edition, Pearson Prentice Hall ISBN S. Kenny, Ph.D., P.Eng. ENGI 5708 Civil Engineering Systems Lecture 02