Hands-on Activity Simulating the Bug

Learning Objectives

After this activity, students should be able to:

• Follow the design process to modify an App Inventor app.
• Analyze data collected by an Android app manually or by developing an algorithm, and identify how this analysis compares to the same data analyzed by the application.

Educational Standards

Each TeachEngineering lesson or activity is correlated to one or more K-12 science, technology, engineering or math (STEM) educational standards.

All 100,000+ K-12 STEM standards covered in TeachEngineering are collected, maintained and packaged by the Achievement Standards Network (ASN), a project of D2L (www.achievementstandards.org).

In the ASN, standards are hierarchically structured: first by source; e.g., by state; within source by type; e.g., science or mathematics; within type by subtype, then by grade, etc.

NGSS: Next Generation Science Standards - Science

Common Core State Standards - Math

International Technology and Engineering Educators Association - Technology

State Standards

Materials List

Each group needs:

• computer with Internet access
• Android device (Bluetooth capable)
• Disease Transmission Tracking Worksheet
• Disease Transmission Tracking Results

For the teacher's use:

• App Inventor Cheatsheet

Worksheets and Attachments

Pre-Req Knowledge

A working knowledge of App Inventor, which can be gained by completing many of the tutorials on the MIT website listed in the Additional Multimedia Support section. Several other lessons in the TeachEngineering collection use App Inventor. For example, Program Analysis Using App Inventor is an excellent lesson for students or teachers to learn the ins and outs of App Inventor.

Introduction/Motivation

The world around us is very complex with large numbers of variables and objects, even in some small-scale systems. Scientists and engineers use models to simplify the task of understanding how these systems function or designing software and hardware to solve problems involving these systems.

One such complex system in biology is a population. Tracking each individual would be time-consuming and calculation-intensive. Epidemiologists develop models to predict how diseases spread in populations; then they test the models and improve them as more data is collected and compared to predictions.

In general, disease transmission models can be applied to different areas, but when drilling down to the specific neighborhoods or individuals, models often fail in their predictions. Thus, the models for small, isolated populations are different than those for large, dense urban populations.

In this activity, you will play the part of an epidemiologist and software engineer by collecting data and writing an algorithm to help you analyze it. You will design a modification to a disease (provided) by modifying an Android app using App Inventor. In doing so you will apply the software/systems design process, which is cyclical with all steps being equally important. The activity will focus you on the evolution phase in which a solution (in this case an Android app) will be modified to make it apply in a different way/situation. This is similar to how software engineers collaborate with epidemiologists to analyze large amounts of data and make predictions on the spread of diseases. Then you will discuss ways of reducing the spread of disease.

Diseases often evolve and change into different strains that require different medical treatments. An example of this is influenza, which continually has different strains enter into existence or disappear, only to re-emerge later. These new (and old) strains must be tracked and simulated. The well-known breakout of the H1N1 flu is one instance in which a new strain emerged and great effort and expense was employed to simulate the spread of the disease in order to develop a treatment.

In this activity, you will simulate part of the job of a software engineer. Software engineers produce models that can be used to predict patterns in disease transmission, determine lethality of the disease, and learn the origins of the disease. These models are critical for the development of cures. Biomedical engineers work with doctors to discover how the disease spreads, how it affects the human body and develop cures. How do you think these models are developed? Does one model fit all diseases or do they need to be customized?

Procedure

Teacher Background Information: App Inventor Attachment Information

• App Inventor base app source: Simulating the Bug Empty Algorithm Source (zip) - This is the source code for the algorithm designers that students may modify in App Inventor. It requires App Inventor.
• App Inventor base app binary: Simulating the Bug Empty Algorithm Binary (apk) - This pre-built App Inventor app has no algorithm; it is provided to show/test default behavior. It requires an Android device or emulator.
• App Inventor example app source: Simulating the Bug Full Algorithm Source (zip) - This is the source code for the bare-bones algorithm that students may modify in App Inventor. It requires App Inventor.
• App Inventor example app binary: Simulating the Bug Full Algorithm Binary (apk) - This is a pre-built App Inventor app that will apply the bare-bones algorithm to a given dataset. It requires an Android device or emulator.

Before the Activity

• Install App Inventor on the computers that student groups will use to modify a disease and then track the results. They will also need the apk and zip files mentioned above.
• Make copies of the Disease Transmission Tracking Worksheet (which students use to manually record contact events to manually analyze or to help with algorithm creation) and the Disease Transmission Tracking Results (which students use to manually track infection events from the tracking worksheet or to check algorithm results). Instructions for using sheets: Students can use the tracking worksheet as a practice exercise to help develop an algorithm for checking and passing on the infection. You may simulate a small-scale study with them in the classroom and using physical proximity (closer than arm-length to designate a contact event) before using the application with Bluetooth. They may then use the tracking results sheet to assist them in data organization.
• Review the App Inventor Cheatsheet, which outlines how to create a bare-bones algorithm with App Inventor. The cheatsheet is intended to inform the teacher on what constitutes a working algorithm, but may be used with students who have not been exposed to designing algorithms. This algorithm can also serve as a skeleton on which to add more functionality, such as disease immunity or recuperation. Customize its use to the needs of your students.

With the Students

1. Divide the class into groups of three.
2. Direct student teams to use App Inventor to design their own diseases with unique transmission characteristics by altering the full algorithm version (use the Simulating the Bug Full Algorithm Source and Simulating the Bug Full Algorithm Binary) through step-by-step procedures for calculations that take into account different disease properties such as ease of transmission, length of contact required, and possibly accounting for immunity.
3. Next, have groups test the disease algorithm's success using the Android data collection app or by using some of the pre-loaded examples that may be selected from the "Analyze" screen (general movement patterns provided) from the app, or by using data that was collected in class using the associated lesson's disease transmission app (apk) during the Passing the Bug lesson.
4. Direct groups to record the success of their diseases for different population movement patterns. The simplest way to do this is to run the analysis program and record the maximum number of infected individuals or by determining the amount of time it takes to infect a given fraction of the population to become infected. Graphing the number of infections as a function of time can perform more detailed analysis of the transmission pattern. As an example, constraining contact patterns in a hallway often give different results than those in an open gym. Typical patterns:

• mall, compact group: steep-sloped linear or sigmoidal
• individuals in a linear pattern: flatter-sloped linear
• small groups with traveling infected: stepped increase as new groups are infected

5. Depending on infectiousness and minimum number of contacts, some diseases may transmit better if individuals are in contact for longer periods of time rather than brief contacts with wide-ranging movement.
6. As time permits, further activities include comparing with other students and/or customizing their diseases for different simulations. For example, you can change the infectiveness of your disease and test how a disease progresses in the different population structures (urban, rural, world-traveler) if it is highly infectious or more difficult to spread.
7. Conclude with a brief writing assignment, as described in the Assessment section.

Vocabulary/Definitions

communicable: Able to be passed from one organism to another.

epidemiology: The study of the patterns involving health events such as disease.

host: An organism that is infected with a pathogen.

immunity: The ability of an organism to resist infection.

infectious disease: A disease that is caused by an organism such as bacteria or viruses invading another organism.

pathogen: An organism that causes a disease.

transmission: The process of transferring a pathogen from one host to another.

vector: A different species of organism that can move a pathogen between hosts.

Assessment

Pre-Activity Assessment

Questions: As a quiz or discussion questions, ask students about how the design process relates to creating and testing software.

• What are the steps that software engineers follows in the software/systems design process? (Answer: Problem analysis, design, implementation, testing and evolution.)
• Why is the evolution phase so important to software engineers? (Answer: This is the phase when solutions can be applied to fit different problems. Past experiences and solutions can be used to help solve different problems. By beginning with a similar solution, new solutions are easier to develop.)
• Why does the design process work well in the evolution phase? (Answer: Evolving a solution is a logical conclusion for the designed solution. To properly complete the evolution phase, similar problems must be analyzes, solutions designed, implemented and tested.)

Post-Activity Assessment

Writing: Assign students to complete the following writing prompts:

1. Explain how you applied the design process in this activity. (Example answer: The design process was applied in two ways. First, it was partially applied by focusing on the evolution step. To accomplish the evolution step, a second mini design process was completed when I analyzed the changes I wanted to make. I designed a solution and implemented it. Analysis of the results of the modification was like the testing phase.)
2. Explain how you modified the disease that is simulated in the App Inventor app in this activity and the results of your analysis. (Answers may vary widely from the example answers. Example answer 1: I required that my disease was only capable of being transmitted to users having an odd number. This simulated a population in which half of the members were immune to the disease, which resulted in it being much more difficult to transmit. Example answer 2: My algorithm counted the number of contacts between infected and uninfected users and only passed the disease on after three contact events. This made my disease easier to spread in groups with little movement and more difficult to spread to users moving quickly through an area.)
3. Relate your experience in this activity to the real world. How important do you think software engineering and the development of these models and simulations are in the research and prevention of diseases, spread of diseases, epidemics? (Example answer: The development of these simulations and models is critical to understanding how diseases are transmitted and how diseases will likely progress. If the medical community has a glimpse, albeit an educated guess, they are able to determine if quarantines are needed, how to educate the populace and to hopefully develop cures more quickly.)

Troubleshooting Tips

A description of the different methods in the App Inventor code is available by clicking on the question mark on the algorithm block in App Inventor.

Additional Multimedia Support

See additional resources at the MIT App Inventor website, http://appinventor.mit.edu/, including instructions and tutorials for installing App Inventor (see http://appinventor.mit.edu/explore/setup-mit-app-inventor.html).

Copyright

Contributors

Supporting Program

Acknowledgements

The contents of this digital library curriculum were developed as a part of the RET in Engineering and Computer Science Site on Infusing Mobile Platform Applied Research into Teaching (IMPART) Program at the University of Nebraska-Omaha under National Science Foundation RET grant number CNS 1201136. However, these contents do not necessarily represent the policies of the National Science Foundation, and you should not assume endorsement by the federal government.