## 2 Related Works
### Open Issues  
There are several open issues that have been found in the reviewed literature that are yet to be properly solved with regard to the main topics and ideas that have been put forward in this manuscript. Table 1 highlights the pros and cons for each of the studied solutions. In a more general manner, the open issues found are as follows:  
1. Lack of focus on cybersecurity implementation. Security features usually come as an afterthought rather than having them embedded in the development of the solution from the very beginning. In most of cases of the reviewed literature they are given negligible importance, whereas in some others cybersecurity is nonexistent as a feature. This might create major issues when monitoring cattle or performing Smart Farming activities, as the collected data can be tampered with easily, whereas other pieces of information (what kind of protocols must be used for data transmission, which components are vulnerable to cyberattacks, etc.) are missing. 2. Lack of UAV tailoring for the purpose of cattle monitoring. Rather than having one or a collection of UAVs specifically prepared for the purpose of monitoring cattle (something that demands specific components that can be used for data transmission, UAV control or information security) commercial models have been used for the most part to perform the missions. While this might work in some cases, there are others where, due to the communications range or the information flows, using purely \begin{table}
\begin{tabular}{c c c} \hline \hline
**Authors** & **Advantages** & **Disadvantages** \\ \hline
[10] & Usage of algorithms to determine accurate livestock positions. & Security, or tailoring a UAV for the scope of the paper is not considered. \\
[11] & Profuse data processing used, usage of mobile application. & No security considered. Different scope from the one put forward in our paper. \\
[12] & UAVs used for livestock guidance. & No security is taken into account in the paper. No usage of specific UAV. \\
[13] & IoT-based, reliable deployment of technologies. & No security is evaluated in the paper. UAV as a closed solution. \\
[15] & Real-world development oriented to cattle monitoring in the countryside. & No security considerations. Commercial UAV rather than tailored solution. \\
[16] & Usage of Unmanned Aerial Systems for cattle monitoring in the countryside. & No security considerations in the paper. No usage of tailored UAV. \\
[17] & UAV built from scratch with the purpose of livestock monitoring. & No information about how to secure data or how to create a secure infrastructure. \\
[18] & Experiments proving that UAVs can be used for livestock monitoring. & Secure framework or UAV building are out of the scope of the paper. \\
[19] & Development of the concept of a & No security framework is taken into consideration. No specific \\
[20] & Usage of Convolutional Neural Network (CNN) for cattle counting purposes & UAV building. \\
[21] & Usage of Deep Learning for visual localization and individual identification & UAV preparation for livestock monitoring is not considered. \\
[23] & UAVs are used for measurement of specific parameter (spatial proximity) & Security components have not been described, nor any kind of framework. \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Advantages and disadvantages of the studied UAV solutions. multi-purpose commercial UAVs might present issues that could limit the usefulness of such solution. 3. Lack of description in hardware and software component interweaving and integration. Partially because of the previous open issue, most of the components used in the deployments performed are taken for granted and there is very limited research on how to build hardware and software parts with the specific purpose of cattle monitoring adapted to the actual needs of farmers. In addition to that, cybersecurity features are still largely missing.