GEOG 110 – Lab #1 – Getting Started with STELLA – UPDATED VERSIONStarting STELLA using the Citrix serverUsername: <emailed to you>Opening an Existing ModelPeople on the Island is an example of a stock, and stocks are always symbolized in STELLA by a rectangle.Building a Simple Model of Our OwnRunning a Model and Looking at OutputGEOG 110 – Lab #1 – Getting Started with STELLA – UPDATED VERSIONDue time: 23:59 hours September 23, 2005. Objectives: Develop a basic familiarity with the STELLA software; learn how to get itstarted, navigate its views and use its controls, recognize the symbols ituses to represent a model, the basics of constructing models and runningthem.Background: STELLA is the modeling software that we will use throughout this courseto construct models of environmental systems. STELLA is a particularlyuser-friendly modeling system because it represents models usinggraphical flowcharts. Most approaches to modeling require you to convertyour ideas about the physical world into a set of algorithms and equations,and then to write your own software or code to create a functionalmathematical representation of the system. This is not so with STELLA:You still need to conceive of how you will abstract the system into amodel, but constructing your model doesn’t require you to write code, butrather to build something more akin to a flowchart that describes how yourmodel will work.The course textbook, Dynamic Modeling of Environmental Systems,includes version 5.1.1 of STELLA on the accompanying CD-ROM. Alsoon this disc, you’ll find a series of sample exercises that correspond tothose found in each chapter of the text (except Chapter 2). While we willbe making use of those sample exercises, we are going to use a newerversion of STELLA, version 7.0.1. This software is available to youthrough the university’s Citrix server, which allows you to run itanywhere! You should even be able to use it on a computer at home,provided you have an appropriate Windows operating system, an Internetservice provider and can browse the University web site to reach the Citrixserver. Detailed Instructions for how to get STELLA 7.0.1 started usingCitrix can be found below in the Methods section.Resources: This lab exercise does not include the background and theory of usingSTELLA. Instead it shows you step by step how to do some of the basicoperations required to get the software started and to use it. However, youshould read some of the materials that do describe how to use STELLA tohelp you understand how it works and to help you successfully completethis lab exercise. Section 1.7 in the course text, Appendix: GettingAround in STELLA on pages 23 through 27 is a very concise and usefulplace to read about STELLA modeling. A second resource is the onlinehelp that provides complete technical details about the software. A furtherresource is the book that has been placed on reserve, An Introduction toSystems Thinking. This is a comprehensive and detailed look at theSTELLA modeling language, its symbols and customs. If you want the1exact details of how something in STELLA works, the aforementionedtext is a good place to look (several copies are on reserve at the HouseUndergraduate Library).Procedure: This first walk though of STELLA requires you to follow a series of manysteps. To make your task easier, they are described below sequentially,and broken up into sections to help you organize what you are doing.Starting STELLA using the Citrix server1. Open the following URL in a web browser: http://oasis.unc.edu/citrix. Youshould see this login screen:2. In order to use Stella in the Citrix Application, please log in as in thefollowing: Username: <emailed to you>Password: <emailed to you>3. The Domain should be set to asntdomain1 as seen above (if it is not,change it so it is set appropriately).4. Once all the fields are filled in correctly, click on Log In.5. Next you’ll be presented with a window containing the STELLA iconas in the following: 6. Double click on the STELLA icon to get the software started.27. Because the software is being served to your computer from a remoteserver, you may be presented with some windows that inform of youof this fact, and ask your permission to run the software in this way.You’ll need to respond in the affirmative if you want STELLA to run.Opening an Existing ModelBefore we try and make a model of our own, we’ll begin by opening anexisting model from the set provided with the textbook, and having a lookat it to see what a typical STELLA model contains, and the different levelswe can use to view models. STELLA model files have the extension .stm.We’re going to have a look at chap1a.stm, the model described in Chapter1 of the textbook.8. Copy the following link and paste it into a new browser window toopen the course data directory:http://www.unc.edu/courses/2005fall/geog/110/001/data9. Right-click on chap1a.stm and save it to D:\temp on the 322 labmachines, or anywhere you’d like on your own machine10. Using the menu, click on File  Open (or type Ctrl+O on thekeyboard), and open the file from the location where you saved it.Exploring the Components of an Existing Model11. The model should open, and inside the STELLA window, you shouldsee a window that looks like this:12. We’ll now learn about some different parts of STELLA models byselecting them. By default, the Hand tool should be the selected tool;3it allows us to select and highlight model components. Use the Handtool to click once on the rectangle labeled People on the Island. Itshould become highlighted when selected, like this:People on the Island is an example of a stock, and stocks are alwayssymbolized in STELLA by a rectangle.13. Next, let’s select the item labeled Births:Births is a flow, which always symbolized in STELLA by a pipe with avalve in the middle.We can do the same for Birth Rate, which is a converter and is alwayssymbolized by a circleConverters help us deal with units so our models are consistent in thequantities of which they keep track. Note that the Birth Rate converter is linked to Births by a connector,which is always symbolized by a single-line arrow. Connectors showthat there is a cause-effect relationship between the items