303 lines
14 KiB
Plaintext
303 lines
14 KiB
Plaintext
\documentclass[10pt, draftclsnofoot,onecolumn]{IEEEtran}
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\def\changemargin#1#2{\list{}{\rightmargin#2\leftmargin#1}\item[]}
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\let\endchangemargin=\endlist
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\usepackage{todonotes}
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\usepackage{caption}
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\usepackage{pgfgantt}
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\linespread{1}
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\begin{document}
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\title{Fenceless Grazing Tech Review - Danila Fedorin}
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\author{Danila Fedorin, \and Matthew Sessions, \and Ryan Alder}
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\maketitle
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\begin{abstract}
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The Fenceless Grazing Collar System aims to reduce the burden
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on farmers caused by the need of constant manual herding of livestock.
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The project will use LoRa wireless technology, and will prevent
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animals from leaving prescribed grazing areas through the use of
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an auditory or electrical stimulus. The project will additionally provide
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data gathering features. As a member of the FGC team, I will be
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responsible for creating the smart application that will be used
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to control the wireless collars, as well as some supporting
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software such as an HTTP API server.
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\end{abstract}
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\pagebreak
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\tableofcontents
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\pagebreak
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\section{Role}
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My role in this project is the development of the smart application which
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will be used to control the Fenceless Grazing Collars in the field. This
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includes the actual application, as well as the software to support
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the app, such as a web server for authentication and data retrieval.
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\section{Team Goal}
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The goal of the Fenceless Grazing Collar (FGC) System is to reduce
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the amount of manual labor required for keeping farm animals. The FGC system
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does this by automating the process of keeping animals within their prescribed
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grazing area through the use of GPS location tracking, as well as audio
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and electric stimuli. Additionally, the FGC aims to provide information
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about the behavior of the farm animals to their keepers, with the goal
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of improving their understanding of the livestock.
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\section{Responsibilities}
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\subsection{Smart Device Application}
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A major component of this project is the creation
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of an application that is capable of adjusting
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the settings of the wireless collar devices. This
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section describes the components of this application.
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\subsubsection{Platform}
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The Android platform makes up more than half of the market share
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in the United States \cite{android-share}, with a majority of the remaining share taken
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up by Apple iOS. Because iOS requires an Apple device to perform
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development, and because Android devices are
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on average more than 50\% cheaper than iPhone devices \cite{iphone-price}, we will
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use the Android platform for developing the mobile application
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associated with this project.
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% https://www.businessinsider.com/android-stops-us-market-share-decline-2013-5
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% https://www.forbes.com/sites/amitchowdhry/2015/02/03/average-iphone-price-increases-to-687-and-android-decreases-to-254-says-report/#4d9d29a3539e
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\subsubsection{Language}
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There exists a variety of available technologies and techniques suitable
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for creating an Android application. The most common way for developing
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Android apps is using the Java programming language,
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utilizing the standard Android tooling. Such tooling includes
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the Android Studio Integrated Development Environment (IDE),
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and the Gradle build system. However, since Android's creation,
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multiple other ways of developing Android applications have been introduced. For
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example, technologies such as the Ionic Framework \cite{ionic} and
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React Native \cite{react-native} have been created, allowing for the creation
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of Android applications using the JavaScript programming
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language. More recently, Google announced that JetBrains' Kotlin
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language will be made an official language of the Android
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platform \cite{android-kotlin}.
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%https://ionicframework.com/
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%https://facebook.github.io/react-native/
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%https://www.theverge.com/2017/5/17/15654988/google-jet-brains-kotlin-programming-language-android-development-io-2017
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The use of JavaScript was ruled out due to its weak type system.
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The language does not undergo a process called "type checking",
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which means that certain bugs that can easily be detected
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in other languages may go unnoticed in a JavaScript program
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until they are observed in practice. Since this application
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must reliably control the wireless collars, this is an
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unnecessary risk.
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The choice then remains between Java and Kotlin, both
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official languages of the Android platform. For our
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purpose, Kotlin has advantages over Java. First,
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Kotlin has a stronger type system, which, as described
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above, helps prevents certain bugs before they are
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observed in practice. Second, while Kotlin has access
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to all features of the Android platform that Java does,
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it has significantly less "boilerplate" code. This will
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help reduce the amount of code requiring maintenance,
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and thus reduce the number of mechanical issues with the final code.
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\subsubsection{Backwards Compatibility}
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Because vendors can customize the Android operating system prior
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to using it on their products, a variety of Android devices
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run an "outdated" version of the Android platform, resulting
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in a severe fragmentation of the overall codebase. Since maintaining
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compatibility with every Android version on the market is not viable,
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the project will focus on the version of Android supported by 95\%
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of Android devices at the time the project implementation begins.
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This will allow the project to target a majority of available
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devices, while at the same time not being bogged down by the
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compatibility requirements with very old version of Android.
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\subsection{Data Storage}
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Data storage is a major component of the fenceless grazing project.
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It is important that the collars collect and store meaningful data
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about the animals in the field, to be analyzed by the client.
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\subsubsection{Type of Data Collected}
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The data collected will consist of GPS coordinates of the animal,
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taken every 15 seconds, as well as instances of the activation
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of the collars' sound and shock features. This way, the client
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can monitor the locations and habits of the animals, as well
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as quantitatively assess the number of items that the animals
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attempt to leave the prescribed area. Each data point will
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be associated with the collar that produced it, such that
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behaviors of individual animals can be easily analyzed.
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\subsubsection{Storage Type}
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An SQL database will be used for storing the data generated
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by the collars. The technology chosen for this is MariaDB.
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MariaDB \cite{mariadb} was chosen because of its permissive license
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and compatibility with MySQL \cite{mysql}, another SQL dialect that is very
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commonly used in the industry. There exist other technologies
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for storage, such as MongoDB, which do not use the relational
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model used by SQL-based databases. The advantage of NoSQL databases
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is the ability to store data in arbitrary formats, without
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specifying prior schema. On the other hand, SQL-based
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systems (including MySQL and MariaDB) support concurrency,
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which is much more useful for our project due to the future
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need to scale the fenceless grazing system. Additionally,
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we already know the format of our data, making the benefit
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of flexible data storage irrelevant to our use case.
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% https://mariadb.org/
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% https://www.mysql.com/
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\subsubsection{Storage Hardware}
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Because MariaDB and MySQL require a server machine, a Linux machine
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will be used to host the database. This machine will be
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a Raspberry Pi, a small and low-power Linux single-board
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computer. This computer not only has a full-featured
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Debian Linux operating system, but also allows for the
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addition of hardware components, which will be used
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for communicating with collars in the field. Among the
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hardware components compatible with the Raspberry Pi \cite{raspi} is a
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LoRa shield, which allows the Pi to send and receive
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LoRa signals. This is ideal since the server machine will also act as the LoRa
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gateway, serving as the liaison between the collars
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deployed in the field and the rest of the project.
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Alternative implementations include an AVR-based microcontroller
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equipped with ethernet and / or Bluetooth. Such a controller
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would be integrated with a LoRa receiver and transmitter,
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and programmed to send data to some other storage medium,
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potentially a Virtual Private Server (VPS). This
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implementation was dismissed due to the additional
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complexity introduced by separating the LoRa receiver
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and transmitter from the storage medium. This leaves
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room for issues such as network errors between
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LoRa and the SQL machine, which are entirely
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avoided my using a Linux machine (Raspberry Pi) with support
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for external hardware components (LoRa shield).
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% https://www.raspberrypi.org/
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\subsection{App API Server}
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An API server is needed to allow users of the Android
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smart application to interact with the fenceless collars
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deployed on farm animals. Smartphones do not have
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hardware that can communicate using the LoRa protocol,
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which is used for collars. As such, an intermediate
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device, a server that can communicate with both smartphones
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and LoRa, must be used.
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\subsubsection{Server Technology}
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The server will run on the aforementioned Linux machine.
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This is because it is rather expensive, in terms of both
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price and complexity, to introduce two server machines
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for the individual tasks of SQL data storage and smartphone
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app support.
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The server will use the Python \cite{python} programming
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language, which is natively supported by the Raspberry Pi,
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to host an HTTP(S) server on the local network. The
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use of Python will allow for rapid development, and give
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direct access to the server's LoRa hardware. While other
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languages, such as Go, are also commonly used for API
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implementations, they lack the first-class support that
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Python receives from the Raspberry Pi project. Additionally,
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Python is currently at the top of the popularity rankings
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for programming languages, leading to increased access
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to documentation and support.
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The Gunicorn \cite{gunicorn} server will be used to expose the Python
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application to the Android application clients. While
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other web servers, such as Apache and nginx, are very
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commonly deployed in production, Gunicorn has excellent
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support for Python, which will allow the team to
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quickly develop the HTTP application.
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% https://www.python.org/
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% https://gunicorn.org/
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\subsubsection{Authentication}
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The mobile app will use JSON web token (JWT)
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to allow the mobile application to make multiple requests
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without having to continuously provide a username
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and password to the server. The idea of JWT is that
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a JSON (JavaScript Object Notation) object, containing
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session information (such as the identity of the current user),
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is encrypted with information from the server. The encrypted
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version of this object is then sent to the user, and can be
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used as a "proof of identity". Since only the server can decrypt
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the token, the user cannot deliberately make changes to it, preventing
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security breaches. Once a user logs in, a JWT token will be generated,
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containing the identity of the user and an expiration date, and
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returned to the app. The app will then use the token for further
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requests.
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Cookie-based authentication systems were considered as an alternative;
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This is commonly used in web applications, serving as a different
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way to avoid authentication on every API or web request. However,
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this approach will not generalize well. Using cookie or session-based
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authentication requires more extensive bookkeeping on the client side, which
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complicates the implementation of other clients. In the future, it is
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likely that the smart application will be ported to other platforms,
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including iOS and Web. To ease this expansion, the approach
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requiring the least additional implementation overhead is preferred.
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Because of this criterion, JWT-based authentication is better suited
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for the API server.
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\subsubsection{API}
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There are several ways of communicating data to the mobile application
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from the server. Because writing custom code to encode / decode data
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send between the android application (client) and the server is
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time consuming and prone to errors, priority is given to existing
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encoding / decoding technologies. Of these technologies, Google's
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ProtoBuf \cite{protobuf}, XML, and JSON are the most viable. JSON was chosen
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for this project because of the ease with which it can be decoded,
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as well as due to its compatibility with the JavaScript ecosystem.
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Virtually every language (including Kotlin and Python) has support
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for JSON decoding that is well-tested and supported. This makes
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JSON the most standard choice for an interchange format.
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The aforementioned HTTP server will thus provide a JSON API
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to the client. During each HTTP requests, the client will
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include a JWT token, and, once that token is verified, the server
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will process the relevant information and return a JSON object
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through HTTP containing the resulting data.
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% https://developers.google.com/protocol-buffers
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\pagebreak
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\begin{thebibliography}{99}
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\bibitem{android-share}Alex Cocotas, \textit{Android Bounces Back From U.S. Market Share Decline} \\
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\texttt{https://www.businessinsider.com/android-stops-us-market-share-decline-2013-5}
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\bibitem{iphone-price}Amit Chowdhry, \textit{Average iPhone Price Increases To $687 And Android Decreases To $254, Says Report} \\
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\texttt{https://www.forbes.com/sites/amitchowdhry/2015/02/03/average-iphone-price-increases-to-687-and-android-decreases-to-254-says-report/\#437c18ac539e}
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\bibitem{ionic}\textit{Ionic Framework} \\
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\texttt{https://ionicframework.com/}
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\bibitem{react-native}\textit{React Native} \\
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\texttt{https://facebook.github.io/react-native/}
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\bibitem{android-kotlin}Paul Miller, \textit{Google is adding Kotlin as an official programming language for Android development} \\
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\texttt{https://www.theverge.com/2017/5/17/15654988/google-jet-brains-kotlin-programming-language-android-development-io-2017}
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\bibitem{mariadb}\textit{MariaDB} \\
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\texttt{https://mariadb.org/}
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\bibitem{mysql}\textit{MySQL} \\
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\texttt{https://www.mysql.com/}
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\bibitem{raspi}\textit{Raspberry Pi} \\
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\texttt{https://www.raspberrypi.org/}
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\bibitem{python}\textit{Python} \\
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\texttt{https://www.python.org/}
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\bibitem{gunicorn}\textit{GUnicorn} \\
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\texttt{https://gunicorn.org/}
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\bibitem{protobuf}\textit{Protocol Buffer} \\
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\texttt{https://developers.google.com/protocol-buffers}
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\end{thebibliography}
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\end{document}
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