The links in this document can be found at www.stevens.edu/ciese/istem/science/bdf/
An Introduction to Systems Engineering
Systems engineering activities present an opportunity for students to do engineering the way engineers do it. Students can work together to identify problems or opportunities, explore alternatives, create models and test them. The Internet and computer-aided design software make it feasible for students in multiple locations to work together to develop solutions to complex engineering challenges.
What is a System?
We are surrounded by systems. Some of them are natural and others are engineered. The solar system and a beehive are examples of natural systems. Engineered systems are designed and built to satisfy human needs and wants. Wireless telephone networks, power generation plants and our highways are examples of engineered systems.
A system is collection of different elements that interact to produce results that are not obtainable by the elements alone. An automobile is made up of thousands of parts and each part must work with the others if the vehicle is to function as desired.
From a functional viewpoint, systems have inputs,
Figure 1. This flow chart shows inputs and outputs.
processes and outputs. Inputs are the resources put into a system. Processes combine the resources to produce the output which can be a product, service or enterprise. From a physical viewpoint, the system consists of mechanical, electrical and software components (and even humans) that interact to realize these functions. Many engineered systems, particularly those that incorporate electronics, are built in a way to determine if the system is working properly. To do this the goal of the system and the output are compared. This is called feedback. Systems also have boundaries. Everything outside the boundary of a system is part of another system.

Systems Engineering
Engineers have been building systems from the time of the pyramids. It is no longer possible for a single engineer to plan and execute a complex project. Generally engineers work in teams.
Most engineers are experts in one engineering discipline such as mechanical or electrical engineering. Systems engineering is interdisciplinary in that it seeks to improve the way engineers from different disciplines work together. In the past systems engineers were usually selected from among experienced engineers who demonstrated good communication and leadership skills. Today institutions such as Stevens Institute of Technology have designed courses and programs to formalize the preparation of systems engineers. Systems engineers are trained to look at the "big picture" as they coordinate communication among others and the development of products such as airliners and enterprises such as mass transit and homeland security systems.
Core Principles of Systems Engineering
Engineers create systems for customers but others are also affected by the systems they design. All those affected are referred to as stakeholders. Systems engineering activities continue throughout the entire lifecycle of the system. During the early stages of design it's important to understand the needs of the various stakeholders and translate this into specific
requirements for the system. Requirements detail what the system must do. After the requirements are established the focus is on using the engineering design process to develop,
Figure 2. This V chart can be used as a systems engineering guide.

construct/build, test, use, maintain and retire the system. An important task for systems engineers throughout these phases is to be the "advocate" for the whole system. This means to ensure that all components of the system make their assigned contribution to the system, as well as make sure that the components interact in the way they are supposed to. Assessment should be ongoing and include a continuous feedback loop to insure that the system is working properly and provide an opportunity for continuous improvement.
Dr. Rashmi Jain, an Associate Professor of Systems Engineering at Stevens Institute of
Technology, has identified five core concepts of systems engineering: value, context, trade-offs, abstraction and interdisciplinarity. Systems provide value when they meet the needs of stakeholders. The context of a system is important. Engineers need to consider where the products and processes they design will be used. For example, the engineers who recently designed double-decker passenger train coaches for New Jersey Transit had to make sure that the new cars worked with existing systems including the power lines, platforms, signals and locomotives. Interdisciplinarity supports the systems approach which is based on the idea that systems design must consider the needs of all relevant stakeholders and that design teams are made up of members from many disciplines. This means that a systems engineer needs to obtain a good understanding of the environment (often referred to as the problem domain) where the system is used. Although not an expert, he/she will need a good working knowledge of the different engineering disciplines that are involved in creating the system.
Potential design concepts should be evaluated based on tradeoffs such as cost, time and performance. The goal is to select the optimal solution and recognize that there is no perfect solution for all stakeholders. A tank-like automobile designed to prevent injury during every crash would be inefficient to drive and probably too expensive to build. Instead engineers have focused on seat belts, air bags and designing the structure surrounding the driver and passengers to reduce the forces transferred to them during a crash.
Abstraction is another element of the systems engineering process. Engineers need the ability to abstract a design concept independent of the solution. It's important to consider a wide range of alternative and not select a specific solution too soon. For example, early in the space program NASA wanted astronauts to be able to take notes in a zero gravity environment. They spent millions to develop a ball point pen that would work. Russia solved the problem by having their astronauts use pencils.
Systems engineers are also concerned with risk management. Risk management involves

identifying what may go wrong in a system and then planning to prevent it or solve the problem should it occur. For example, many companies manufacture components for their products in multiple locations so that a tornado or other natural disaster will not totally disrupt production of the final product.
Systems Engineering references:
K-12 Education and Systems Engineering: A New Perspective , Ben Erwin, Tufts University. This is an excellent overview of what systems engineering is and why it can be useful in a K-12 setting. This article includes the Wright brothers an example of a systems engineering case study and a step-by-step guide for developing a systems engineering project for your classroom.
SAGE: Biodynamic Farming: In this telecollaborative project, students in grades 9 - 12 will study and work with appropriate and organic technologies that support sustainable food resources which are necessary to combat current global food shortages. Students will research biodynamic farming systems, conduct investigations, and engage in a series of design challenges. Ultimately, students around the world will collaborate to design an aquaponics system that sustains plant and animal life.
SAGE: Core Concepts of Systems Engineering : This telecollaborative project is designed to provide students in grades 9-12 with an orientation to systems engineering concepts. Students will be provided with an overview of systems thinking including the systems model. Through guided activities students will reverse-engineer a common device that contains both electrical and mechanical components and then create a systems diagram for the deconstructed device.
Students will create reassembly instructions and diagrams that partner schools worldwide will use in their attempt to reconstruct the device.

Biodynamic farming or aquaponics systems are complex projects that can illustrate systems engineering as well as highlight how engineers help to meet the needs of society. This guide should walk you through how you can run this project with your class. It has been broken down into some specific sections; however, these sections are not hard and fast. Most importantly, be sure that students are first introduced to the Problem Definition. The Problem Definition should be a general statement of need. It should not be so detailed that it confines the number of possible solutions to too few a number. Allow students to decide on the further refinement of the project. After that students can progress through the three phases outlined here that give them guidance on how to delineate a complex project into discrete sections. Finally, they should at the end be prepared to present their design. You as the teacher can play the role of the chief systems engineer. For the presentations it would be helpful to have other visitors fill the role of stakeholder to give the design teams a more authentic challenge.
Problem Definition: Your design team will design a biodynamic farm that will work in one of your classrooms or could be adaptable or used in all of your classrooms.
Refine requirements: Consider the context in which your system will operate and value to any relevant stakeholders. Here are some guiding questions to assist you in getting started:

What are the main goals you want your system to accomplish? Produce plants for
___? Raise fish for ___? Use as a model during Ecology Unit?

Based on your goals, what needs (mandatory) and wants (preferences) do you have
for your system? There are a few types of requirements common to many systems

engineering projects: performance (manual vs. automated), safety, cost, and infrastructure. Do not feel confined to these however.
 What constraints will you adhere to?
Functional Decomposition: Divide the system into subsystems and form teams to address each one separately.

Nominate 2 System Engineers: The Systems Engineer’s job have the responsibility of overseeing all aspects of the development of the system, including: o optimizing work flow amongst different teams o ensuring subsystems will integrate properly o keeping the project on the timeline o ensuring the final presentation is completed at the end

General System Design: Create an overall design for your aquaponics system. Take a look at some different hydroponic systems in Appendix 1 and online to guide you. Do not feel compelled to work out every detail. Different teams will work those out in the next phase.

Decompose subsystems: The system as a whole should be broken down into subsystems that can be developed or research separately. Look at some of the resources below and discuss with your group the most effective division of your system.

Assign teams to each sub-system: Each team will focus on researching and testing aspects of their subsystem.
Design, Test, Build: Research each sub-system in teams and explore how possible solutions.
Feel free to build or research online. If you feel confused or lost, consult your systems engineer. Systems engineers should be optimizing workflow and keeping to the timeline. If a

team is falling behind, find help from another group or jump in yourself. If a team is finishing early, have them assist with systems integration and/or assembling the final presentation.
System Integration: Finish with a group meeting to assess how well systems will integrate. You may have to make trade-offs or manage risk.
Assemble the Final Presentation: This presentation should be a cohesive overview of every aspect of your system. Be sure to include the following in your 15 minute presentation:
Pictures, flow diagrams (inputs, outputs, processes), hand sketches of the overall system, engineering drawings, list of materials, schedule of systems monitoring (some examples can be found at the end of this section). You do not have to put all these in your presentation. Use the ones that you feel will be most effective at giving the audience a vision for your biodynamic farm.
See Appendix 2 for some artifacts from other systems engineering projects.
Finally be sure to consider the value of your system to different stakeholders and discuss trade-offs that were made.

Ebb and Flow
Top Drip System

Deep Water Culture
Wick System