Update techreview

techreview.latex

@@ -53,30 +53,30 @@ the settings of the wireless collar devices. This
 section describes the components of this application.
 
 \subsubsection{Platform}
-The Android paltform makes up more than half of the market share
+The Android platform makes up more than half of the market share
-in the United States, with a majority of the remaining share taken
+in the United States \cite{android-share}, with a majority of the remaining share taken
 up by Apple iOS. Because iOS requires an Apple device to perform
-development [citation needed], and because Android devices are
+development, and because Android devices are
-on average more 50\% cheaper than iPhone devices, we will
+on average more than 50\% cheaper than iPhone devices \cite{iphone-price}, we will
 use the Android platform for developing the mobile application
 associated with this project.
-% Source https://www.businessinsider.com/android-stops-us-market-share-decline-2013-5
+% https://www.businessinsider.com/android-stops-us-market-share-decline-2013-5
 % https://www.forbes.com/sites/amitchowdhry/2015/02/03/average-iphone-price-increases-to-687-and-android-decreases-to-254-says-report/#4d9d29a3539e
 
 \subsubsection{Language}
-There exists a variety of available technolgoies and techniques suitable
+There exists a variety of available technologies and techniques suitable
 for creating an Android application. The most common way for developing
 Android apps is using the Java programming language,
 utilizing the standard Android tooling. Such tooling includes
 the Android Studio Integrated Development Environment (IDE),
 and the Gradle build system. However, since Android's creation,
 multiple other ways of developing Android applications have been introduced. For
-example, technologies such as the Ionic Framework and
+example, technologies such as the Ionic Framework \cite{ionic} and
-React Native have been created, allowing for the creation
+React Native \cite{react-native} have been created, allowing for the creation
 of Android applications using the JavaScript programming
 language. More recently, Google announced that JetBrains' Kotlin
 language will be made an official language of the Android
-platform.
+platform \cite{android-kotlin}.
 %https://ionicframework.com/
 %https://facebook.github.io/react-native/
 %https://www.theverge.com/2017/5/17/15654988/google-jet-brains-kotlin-programming-language-android-development-io-2017
@@ -122,17 +122,26 @@ The data collected will consist of GPS coordinates of the animal,
 taken every 15 seconds, as well as instances of the activation
 of the collars' sound and shock features. This way, the client
 can monitor the locations and habits of the animals, as well
-as quantatively assess the number of items that the animals
+as quantitatively assess the number of items that the animals
 attempt to leave the prescribed area. Each data point will
 be associated with the collar that produced it, such that
 behaviors of individual animals can be easily analyzed.
 
 \subsubsection{Storage Type}
 An SQL database will be used for storing the data generated
-by the collars. A single MariaDB server will be used to store
+by the collars. The technology chosen for this is MariaDB.
-the data. MariaDB was chosen because of its permissive license
+MariaDB \cite{mariadb} was chosen because of its permissive license
-and compatibility with MySQL, another SQL dialect that is very
+and compatibility with MySQL \cite{mysql}, another SQL dialect that is very
-commonly used in the industry. 
+commonly used in the industry. There exist other technologies
+for storage, such as MongoDB, which do not use the relational
+model used by SQL-based databases. The advantage of NoSQL databases
+is the ability to store data in arbitrary formats, without
+specifying prior schema. On the other hand, SQL-based
+systems (including MySQL and MariaDB) support concurrency,
+which is much more useful for our project due to the future
+need to scale the fenceless grazing system. Additionally,
+we already know the format of our data, making the benefit
+of flexible data storage irrelevant to our use case. 
 
 % https://mariadb.org/
 % https://www.mysql.com/
@@ -145,12 +154,25 @@ computer. This computer not only has a full-featured
 Debian Linux operating system, but also allows for the
 addition of hardware components, which will be used
 for communicating with collars in the field. Among the 
-hardware components compatible with the Raspberry Pi is a
+hardware components compatible with the Raspberry Pi \cite{raspi} is a
 LoRa shield, which allows the Pi to send and receive
 LoRa signals. This is ideal since the server machine will also act as the LoRa
 gateway, serving as the liaison between the collars
 deployed in the field and the rest of the project.
 
+Alternative implementations include an AVR-based microcontroller
+equipped with ethernet and / or Bluetooth. Such a controller
+would be integrated with a LoRa receiver and transmitter,
+and programmed to send data to some other storage medium,
+potentially a Virtual Private Server (VPS). This
+implementation was dismissed due to the additional
+complexity introduced by separating the LoRa receiver
+and transmitter from the storage medium. This leaves
+room for issues such as network errors between
+LoRa and the SQL machine, which are entirely
+avoided my using a Linux machine (Raspberry Pi) with support
+for external hardware components (LoRa shield).
+
 % https://www.raspberrypi.org/
 
 \subsection{App API Server}
@@ -167,13 +189,21 @@ The server will run on the aforementioned Linux machine.
 This is because it is rather expensive, in terms of both
 price and complexity, to introduce two server machines
 for the individual tasks of SQL data storage and smartphone
-app support. The server will use the Python programming
+app support.
-language, which is natively supportd by the Raspberry Pi,
-to host an HTTP(s) server on the local network. The
-use of Python will allow for rapid development, as give
-direct access to the server's LoRa hardware.
 
-The Gunicorn server will be used to expose the Python
+The server will use the Python \cite{python} programming
+language, which is natively supported by the Raspberry Pi,
+to host an HTTP(S) server on the local network. The
+use of Python will allow for rapid development, and give
+direct access to the server's LoRa hardware. While other
+languages, such as Go, are also commonly used for API
+implementations, they lack the first-class support that
+Python receives from the Raspberry Pi project. Additionally,
+Python is currently at the top of the popularity rankings
+for programming languages, leading to increased access
+to documentation and support.
+
+The Gunicorn \cite{gunicorn} server will be used to expose the Python
 application to the Android application clients. While
 other web servers, such as Apache and nginx, are very
 commonly deployed in production, Gunicorn has excellent
@@ -186,7 +216,7 @@ quickly develop the HTTP application.
 \subsubsection{Authentication}
 The mobile app will use JSON web token (JWT)
 to allow the mobile application to make multiple requests
-without having to continously provide a username
+without having to continuously provide a username
 and password to the server. The idea of JWT is that
 a JSON (JavaScript Object Notation) object, containing
 session information (such as the identity of the current user),
@@ -195,17 +225,29 @@ version of this object is then sent to the user, and can be
 used as a "proof of identity". Since only the server can decrypt
 the token, the user cannot deliberately make changes to it, preventing
 security breaches. Once a user logs in, a JWT token will be generated,
-containing the identity of the user and an experiation date, and
+containing the identity of the user and an expiration date, and
 returned to the app. The app will then use the token for further
 requests.
 
+Cookie-based authentication systems were considered as an alternative;
+This is commonly used in web applications, serving as a different
+way to avoid authentication on every API or web request. However,
+this approach will not generalize well. Using cookie or session-based
+authentication requires more extensive bookkeeping on the client side, which
+complicates the implementation of other clients. In the future, it is
+likely that the smart application will be ported to other platforms,
+including iOS and Web. To ease this expansion, the approach
+requiring the least additional implementation overhead is preferred.
+Because of this criterion, JWT-based authentication is better suited
+for the API server.
+
 \subsubsection{API}
 There are several ways of communicating data to the mobile application
 from the server. Because writing custom code to encode / decode data
 send between the android application (client) and the server is
 time consuming and prone to errors, priority is given to existing
 encoding / decoding technologies. Of these technologies, Google's
-ProtoBuf, XML, and JSON are the most viable. JSON was chosen
+ProtoBuf \cite{protobuf}, XML, and JSON are the most viable. JSON was chosen
 for this project because of the ease with which it can be decoded,
 as well as due to its compatibility with the JavaScript ecosystem.
 Virtually every language (including Kotlin and Python) has support
@@ -220,4 +262,41 @@ through HTTP containing the resulting data.
 
 % https://developers.google.com/protocol-buffers
 
+\pagebreak
+\begin{thebibliography}{99}
+
+    \bibitem{android-share}Alex Cocotas, \textit{Android Bounces Back From U.S. Market Share Decline} \\
+    \texttt{https://www.businessinsider.com/android-stops-us-market-share-decline-2013-5}
+
+    \bibitem{iphone-price}Amit Chowdhry, \textit{Average iPhone Price Increases To $687 And Android Decreases To $254, Says Report} \\
+    \texttt{https://www.forbes.com/sites/amitchowdhry/2015/02/03/average-iphone-price-increases-to-687-and-android-decreases-to-254-says-report/\#437c18ac539e}
+
+    \bibitem{ionic}\textit{Ionic Framework} \\
+    \texttt{https://ionicframework.com/}
+
+    \bibitem{react-native}\textit{React Native} \\
+    \texttt{https://facebook.github.io/react-native/}
+
+    \bibitem{android-kotlin}Paul Miller, \textit{Google is adding Kotlin as an official programming language for Android development} \\
+    \texttt{https://www.theverge.com/2017/5/17/15654988/google-jet-brains-kotlin-programming-language-android-development-io-2017}
+
+    \bibitem{mariadb}\textit{MariaDB} \\
+    \texttt{https://mariadb.org/}
+
+    \bibitem{mysql}\textit{MySQL} \\
+    \texttt{https://www.mysql.com/}
+
+    \bibitem{raspi}\textit{Raspberry Pi} \\
+    \texttt{https://www.raspberrypi.org/}
+
+    \bibitem{python}\textit{Python} \\
+    \texttt{https://www.python.org/}
+
+    \bibitem{gunicorn}\textit{GUnicorn} \\
+    \texttt{https://gunicorn.org/}
+
+    \bibitem{protobuf}\textit{Protocol Buffer} \\
+    \texttt{https://developers.google.com/protocol-buffers}
+\end{thebibliography}
+
 \end{document}