The Systems Approach to Problem Solving

Transcription

1 The Systems Approach to Problem Solving I. Introduction This course introduces the methodology systems engineers use to solve problems. You will learn about many concepts and tools that systems engineers use on a daily basis to solve problems. This course will also focus on developing your skills in technical writing and group work as a foundation for future courses. Additionally, you will be introduced to speakers from the Systems Engineering faculty and from industry who will show you how they use systems methodology across a broad range of disciplines. II. Course Objectives This course will introduce students to: A sampling of different systems engineering concentrations The underlying methodology of systems engineering The basic analysis tools of a systems engineer. The methodology of writing engineering (technical) papers as preparation for later course work Small-group work situations The use of systems engineering computer software Case-based learning experiences A hands-on design project By the end of this course, you should have a basic understanding of systems engineering. You will also have a general understanding of the following tools, processes, and industries: TOOLS INDUSTRIES 1. Project Management 1. Telecommunications 2. Queuing 2. Manufacturing 3. System Optimization 3. Service Processes 4. System Integration 4. Transportation systems 5. Environmental systems III. Course Materials There is no textbook for this class. There are, however, handouts including homework assignments, case problems, and lecture readings. All materials will be distributed in class. IV. Grading 1) Five graded group homework assignments 40% 2) Midterm Exam 15% 3) Final Exam 15% 4) Oral Presentation 10% 5) Robotics Project 10% 6) Class Participation* 10% *This class has deliberately been kept small because class participation is vital to both the class's success and your learning. Therefore, consistent attendance is vital and active participation is key. Consequently, a significant portion of your grade will be tied to your participation. V. Written Homeworks 1

2 One of the goals of this class is to prepare you for the technical writing assignments you will soon encounter in your engineering courses and will continue to see throughout your engineering career. There are five written assignments which you must complete with a group of two or three other students. Partners will be assigned for some of these assignments, but for others you may choose your own partners. Papers will be limited to a maximum of two typed pages at 11 point font with 1 inch margins. This stringent limitation is meant to teach you how to present a substantial amount of information in a concise and well organized paper. Each group will be required to meet with the TA to discuss and defend two of the four papers. (The papers to be discussed will be selected by the professor). The TA will discuss both the writing style, and the content of the papers. These discussions will be considered part of your grade for this course. More information on these written homeworks will be given as the semester progresses. VI. Robotics Project You will work with a partner to define the requirements for a robotic system. Then you will design and build the system and demonstrate it to your instructors. Your system will be required to interact properly with the robotic systems of other teams. The robotics project embodies the essence of systems engineering. You will learn what it means to integrate the pieces of a system to produce an effective whole. VII. Tutorial Presentation You will be required to make a 15 minute in-class team presentation. You must research one of the tools or topics discussed in class or an application of the tools and make an informative tutorial presentation. This presentation should focus on teaching something beyond what you have learned in class that other students will be interested in. You should bring materials to distribute to your classmates that will aid in your presentation, but you will not have to turn in a written report. You will be responsible for answering in depth questions about your topic and will be graded on both content and presentation. 2

3 TOPIC I: PROJECT MANAGEMENT Class #1 "Course Introduction" Bulkpack: Introduction to Project Management Look at Assignment #1 (airplane problem, not graded) SYS 140 Course Plan Introduction to Project Management You will be immediately engaged in the systems problem of designing an airplane, and asked to develop questions that you would consider at the beginning of the planning process. The instructor will guide you in asking appropriate questions for the problem at hand. You will then take your questions home and complete Assignment #1 found in your assignment pack. Class #2 Turn in completed Assignment #1 (airplane problem, not to be graded) Bulkpack: Sample Gantt Chart What Determines the Schedule? Bring your completed assignment #1. The class will begin by the professor bringing together the work of the individual groups. The important issues (questions?) will be listed on the board. The rest of the time will be devoted to setting up a time line for the tasks the students have identified as a class. The class will then put together a master project schedule. "Computer Assistance, using Microsoft Project" Bulkpack: Tips for Microsoft Project, Project Planning Computer assistance - Microsoft Project The beginning of this class is devoted to showing how the parts of a project can be organized with a computer program such as Microsoft Project. The last part of the class should be devoted to distribution and explanation of Homework Assignment #2, followed by initial work on the assignment in the same groups as for assignment #1. For Assignment #2, you should formulate proper questions and a proper project methodology for building a house. You should present your plan in a Microsoft Project Gantt chart with a clear critical path. Look at Assignment #2 (build a house) The groups will write a 2 page paper (plus Gantt chart), due in one week. In the report, take the role of the contractor. You should explain to your sponsor and workers how they will build the house. You should justify/support your plan. CLASS TOPIC II: SYSTEMS METHODOLOGY Class #3 "Introduction to Systems Engineering" Bulkpack: Outline of discussion Process for Systems Engineering; Definitions of Systems Engineering; Suggested Courses for Application Foci "The Role of Systems Engineering" Introduction to Systems Engineering Each student must develop and articulate his/her own expression of the meaning of Systems Engineering. A systems engineer examines an entire system holistically rather than in independent pieces. Before any questions can be answered, the right questions must be asked. We will discuss a car analogy to bridge many engineering fields. We will discuss a human analogy to show that systems engineering looks at a holistic system, not individual pieces. Systems exist in every environment: environmental, telecommunications, manufacturing, service, etc. The Role of Systems Engineering Examples of systems or processes that have gone wrong will be introduced to teach you the mistakes that are made when the up-front questions are neglected or poorly designed. Together, we will distinguish the terms Science, 3

4 Mathematics, Engineering (and design), System, Systems Engineering, and Systems Analysis, and Scientific Method. We will show a methodology map that is presented during Systems 490 so that you understand the modeling principles underlying the projects that you may soon work on. Class #4 Design - The System as it Should Be Dr. Zandi handout Guest Lecture by Prof. Iraj Zandi Building a House problem is due (Assignment #2, graded) Students choose partner for Robotics Project (2 people per team) Guest Lecture by Prof. Iraj Zandi Prof. Zandi s lecture should teach you that systems engineering involves a methodology. Namely, you will learn to describe a system as-is, as it should be, and as it will be. In order to achieve the system as it should be, you must first figure out what questions have to be asked and what interactions exist among the different variables of a system. Understand that a question must be defined before it can be answered. CLASS TOPIC III: SYSTEM INTEGRATION: The ROBOTICS PROJECT Class #5 The Robotics Project Bulkpack: Robotics project description and FAQ s Tutorial robot to be constructed by each student or with partners within one week; not to be submitted Team Project Work Plan and Schedule due in 1 week The Robotics Project We will describe the project and the integration process and discuss the tentative project schedule and form the project teams. It is imperative that you coordinate and plan effectively among your team members. Much of the work must be done outside of class time. Both the process and the finished project will be graded. Visit the laboratory (127 Towne) and receive the robotic kits (LEGO Mindstorm). Class #6 Guest speaker (in the classroom) Prof. Wen Shieh The purpose of the guest speaker is to acquaint students with the faculty member and with the application area that he represents. Class #7 Work on projects in the laboratory (127 Towne) Turn in written Team Project Work Plan and Schedule Students should test untried design concepts soon Class #8 Guest speaker (in the classroom) Barry Silverman Begin to negotiate team interfaces (outside of class time) Written interface documents due Class #10 (not graded) The purpose of the guest speaker is to acquaint students with the faculty member and with the application area that he represents. Comment on Work Plans and Schedules, perhaps via . Class #9 Negotiate team interfaces in the laboratory (127 Towne) At the end of this class, each project team should have a clear understanding with its neighbor teams, in writing, about the way in which their robots will interact. They should specify dimensions, locations, orientations, weights, timing, etc. They must put their understanding in a single written document that is used by both interfacing teams. 4

5 Class #10 Work on projects in the laboratory (127 Towne) Written interface documents due. Three design concepts due, in writing. Instructor and teaching assistants help project teams with construction of their robots. We will discuss the potential need for redesign during debugging and integration stages. This is the most painless and least costly time to make changes. Class #11 Work on projects in the laboratory (127 Towne) Instructor and teaching assistants help project teams with redesign, construction, debugging, reconstruction, and fine-tuning of their robots. Students should continue to work on their robots outside of class. We will comment on weaknesses in interface documents and in design concepts, perhaps via . Class #12 Work on projects in the laboratory (127 Towne) Instructor and teaching assistants help project teams with redesign, construction, debugging, reconstruction, and fine-tuning of their robots. Class #13 Demonstration of integrated system operation in the laboratory (127 Towne) A formal team report on the robot project is due in Class #15; see instructions in bulkpack for report content and format. CLASS TOPIC IV: INTRODUCTION TO QUEUES Class #14 Building an Amusement Park Quantifying Randomness Bulkpack: Queuing, Queue Formulae Queuing case study: Building an Amusement Park Ride You will be assigned to design a service system an amusement park ride. In class, we will develop a set of questions related specifically to queuing analysis. You should avoid getting focused on profit and costs, which at this time are not central to the queue design. Your queue related questions can be used to explore queuing-system issues. For example, how often somebody comes into a park is pertinent to the arrival rate. How quickly the ride can pick up new people relates to the service rate. The number of people we can serve on a single ride pertains to the number of servers. Quantifying Randomness This class will make the leap from the questions developed in the previous class to the fundamental issues in queuing analysis. You will learn four fundamental properties of a general queue system: 1) Arrival Rate 2) Service Rate 3) Number of Servers 4) Queue Length and/or Waiting Time This class will teach the theoretical relationships inherent in queues. At the end of this class, you should be able to identify the features of the queues in any service system (bank, elevator, etc.) You should NOT yet be able to identify the TYPES of arrival or service distributions. Class #15 Team robotics reports due Random Number Distributions Bulkpack: Homework Assignments #3 (due Class #16) and #4 (due Class #17) Instructor assigns partners for Assignments #3, #4, and #5 5

6 Probability Distributions You should now understand the different features of a queue such as the arrival and service rate. This class should introduce the different types of arrival and service distributions. We will show data regarding people arriving at Wawa. The interarrival times should typify an exponential distribution. The number of arrivals vs time (in bins) should be Poisson. The timing of the process and its properties and underlying assumptions will be discussed. We will then show data for cars passing a traffic light. The number of cars passing in 5 seconds should be similar to a normal distribution. The service rate for cars at the intersection should be determined. Use the heights of class members to typify a normal distribution; birthdays in class to typify a uniform distribution. For homework, students should seek out one example of each of these three distributions prior to the next class. See assignment #3. Students should be ready to discuss and DEFEND why their process exhibits the assumed distribution. A two page paper should be submitted at the beginning of class #16 discussing their three findings. Presentation of data distributions The discussion of probability distributions should continue. You will write on the board your examples of each distribution. This class will be a discussion, based on underlying assumptions, of why each of the findings is or is not an example of the stated distribution. This class should prepare you to write their paper (Assignment #4) that is due at the beginning of Class #17. Class #16 Defending your Findings Assignment #3 is due (not graded) Models of queuing systems Bulkpack: Queuing Theory packet; EXTEND article; EXTEND libraries; EXTEND sample models; Explanation of model Application of queuing models This class will apply queuing principles and probability distributions for arrival and service via examples and Arena simulation. We will address Waiting Time, Service Time, Queue Length, Utilization, and Throughput. Also, the idea of manufacturing blocking vs. telecommunications blocking will be explained. At the end of the class, you should understand the fundamental concepts of queue parameters and performance measures. Queue parameters include arrival rate, service rate, and number of servers. The performance measures include queue length, average waiting time, and throughput. Class #17 Random number distributions paper is due (Assignment #4, graded) Applying Queuing Principles to Amusement Park design Handout: Assignment #5 (Design of telecommunications and manufacturing systems), due Class #19 This class should summarize the queue principles you have learned the past two weeks. It should show how to apply the summary queuing curves (in Queuing Theory packet) to specific problems. You should be able to relate your queuing knowledge to the questions you developed during discussion of amusement park ride design. You might also define the assumptions you would use to plan such a ride. Class #18 Design issues in telecommunications and manufacturing Bulkpack: Telecommunications and Manufacturing Class Examples Telecommunication system queues: We will present telecommunication entities including servers, bandwidth, and data packets, and show how to relate the queuing concepts they have learned to these systems. Queues in a manufacturing environment: Students will be introduced to inventory, throughput, bottlenecks, and utilization and will be able to model a 2-3 machine manufacturing system. You will discover the properties of a manufacturing system as well as measures of performance (e.g. manufacturing lead time). Class #19 Assignment #5 (Design of telecommunications and manufacturing systems) is due for a grade Bulkpack: Computer Assistance EXTEND; Assignment #6 (EXTEND simulation of Amusement Park Ride, due Class #22); Assignment #7 (Simulation of a telecommunication system, due at beginning of Class #23); EXTEND 6

7 usage; list of EXTEND commands Using EXTEND This class will explain how to use EXTEND to simulate queuing systems. A preworked example in EXTEND will be used in this class. EXTEND allows the manipulation of arrival and service rates in a fast and easy manner. Several examples of simple queues will be shown in which you will see the effects of different arrival/service rates on the performance measures such as Total Waiting Time. You will see a simple EXTEND model involving one input, one server, and one exit. Class #20 Midterm exam (in class) Topics include project management, systems methodology, probability distributions, and queuing analysis. Computer simulation is not included. Suggested format would be two cases: one analyzing a queuing system and one writing a project management list; then a short objective question on the topic of systems engineering methodology. Class #21 Guest speaker - Mark Wilson (Lucent Technologies) Assignment #6 should be discussed with TA by today Handout: Tutorial Presentation assignment, to be presented orally and in writing April 26; students choose partners, 3 per team, by April 10. The purpose of inviting this guest speaker is to show how the telecommunications industry views queuing design. Class #22 Modeling the Amusement Park Ride using EXTEND Spend the class looking at the EXTEND structures in use by groups in Assignments #6 and #7 and answering questions about how to model specific events that they are assuming in their designs. 7

8 Class #23 Assignment #6 due Guest speaker: Vukan Vuchic (urban transportation systems) Bulkpack: Regional Planning problem (Assignment #8, performed individually); read for Class #24, due Class #25 The purpose of hearing the guest speaker is to acquaint students with the faculty member and with the application area that he represents. CLASS TOPIC V: INTRODUCTION TO OPTIMIZATION Class #24 Two-page paper for Assignment #7 is due Optimization concepts Read Regional Planning problem (Assignment #8) before coming to class Mathematical modeling of optimization problems Bulkpack: Assignment #9 (optimization modeling, performed individually), due Class #26 Discuss the Oral Presentation teams and topics; you will specify your partners. We will then present the case study Regional Planning. You should have read this case prior to attending class. In class, the professor will guide you to generate a list of questions they must answer in order to solve the problem. These questions should lead to the concepts of objective functions and constraints. You should formulate mathematical expressions for the objective function and constraints for the Regional Planning problem before the next class. LP: Linear objective functions and linear inequality constraints The professor will let the class generate the objective function and constraints for the case example presented last class. Be sure to include nonnegativity constraints. Several example problems will then be presented to show how to organize information mathematically in these categories. A homework sheet with several more examples may be handed out for you to model individually by the succeeding class. No solution methodology has been taught at this point. At the end of class we will discuss how you would find the answer. How would you conceive the concept of an answer? What is the simplest Regional-Planning-like problem structure? Class #25 Guest speaker (in the classroom) Edward Morlok The purpose of hearing the guest speaker is to acquaint students with the faculty member and with the application area that he represents, Logistics and Manufacturing. Regional Planning model (Assignment #8) is due at the end of class, not graded Understanding computer solutions of optimization models Bulkpack: Assignment #10 (Controlling Air Pollution); model due April 19, computer solution due April 21 Instructor assigns partners for Assignments #10 and #11 The geometry of linear programming The professor will present a simple two-dimensional problem, interpreting it graphically, and solving it via LINPROG. Then the simple optimization problems (Assignment #9) will be examined with LINPROG. You should understand the meaning of feasibility, corner points, and optimality, and should be able to find the optimal values of the objective function and of the variables. You are not expected to understand the solution methodology; rather you are expected to understand how to: 1. Identify an objective function 2. Identify functional constraints 3. Correctly set up the model 4. Interpret the solution 5. Understand the real world implications of the model and solution Excel Solver For the rest of the class, we will go through and example of how to use Excel Solver to solve an LP problem, and apply it to Assignment #9. We will also discuss the objective function and constraint 8

9 functions for the Controlling Air Pollution problem (Assignment #10) and show how to use Solver to obtain and interpret a solution. Class #26 Sensitivity Analysis Assignment #9 (optimization modeling) is due (not graded) Assignment #10 due (Controlling Air Pollution, not graded) Bulkpack: Assignment #11 (Red Brand Canners), due Class #27 You should bring to class a model for the Air Pollution problem. The professor will answer questions regarding difficulties that you have experienced. Sensitivity to constraints The professor will then introduce the concept of sensitivity of solutions for a two-dimensional geometric example. We will use LINPROG to demonstrate the effect of loosening constraints a unit amount and compute the sensitivity; then we will show that the sensitivities (shadow prices) are given as part of the computer solution. We will also discuss a business/manufacturing interpretation of the two-dimensional problem. You should understand how changing the value of a constraint (particularly a binding constraint) affects the value of the objective function. Understanding accounting in manufacturing We will give an example (wooden spoon manufacture) to explain fixed and variable costs. What do we want to optimize? In the Red Brand Canners problem, each recommendation made by the executives is from a different point of view. Each view is too limited and ignores important information. WE will then assist the class with interpretation of the Red Brand Canner problem and clarify the meanings of the items of data in response to student questions. Class #27 Red Brand Canners paper is due at the beginning of class (Assignment #11, graded) Red Brand Canners discussion Summarize the Red Brand Canner sensitivity analysis The instructor will work the Red Brand Canners case for the class (after it is handed in) and describe the real world manufacturing systems that the Red Brand Canners case describes. This should lead into a class discussion about several manufacturing engineering implications. Student tutorial presentations Class #28 Student tutorial presentations Final Exam Includes optimization analysis and computer solution of queuing and optimization problems; it also might relate guest speaker topics and/or student tutorials to the modeling and analysis tools 9