# An IoT-Based Solution for Intelligent Farming +
## 2 Related Work
### Animal Monitoring Platforms  
The monitorization of animals, namely sheep, is one of the main goals of SheepIT. There are several solutions available for different animal breeds, both in the literature and commercial domains. Typically, these solutions are split into two main groups: location monitoring and behaviour/activity monitoring. The former one allows farmers to keep track of animals and thus infer preferred pasturingareas, grazing times or even detect absent animals. The latter group focuses on detecting the type and duration of an animal's activities, such as resting, eating or running. Albeit both kinds of monitoring tasks are relevant for the context of SheepIIT, activity monitoring is particularly important since it is the basis of the conditioning mechanism that it implements. The monitorization of animals' locations was one of the first technologies implemented in the livestock sector. The unpopularity of shepherds' profession, together with the demanding livestock productivity, has led to the deployment of automated solutions for monitoring the grazing areas and duration. Consequently, several solutions arose to address such issue, being the Global Navigation Satellite Systems (GNSS), especially the Global Positioning System (GPS), the most popular technology used. Some examples are the Australian OzTrack platform that allows to upload GPS gathered data (evaluated with on crocodiles) [53], the e-Pasto platform that offers an application to monitor the location of cattle grazing on mountains [54] and the Digitanimal [55], a solution that offers a vast inventory of GPS-based devices for monitoring the location of different animal species (e.g., cattle, goats, sheep, dogs, etc.). These solutions share the use of GPS and resort on web platforms and/or mobile apps to interact with the user. However, they only perform monitorization, and thus still require the use of expensive physical fences. To suppress such a need, some solutions proposed the addition of a virtual mechanism to the existent localization solutions. Two relevant examples are the eShepherd solution [56] applied to grazing cows, and the NoFence platform, developed specially for goats [57]. This later one, available commercially, was tested both on sheep [58] and lambs [59], and the conclusions point to the existence of technical issues and several difficulties on teaching sheep to stay inside the virtual fence. Thus, there are still improvements that must be made in this area. Despite the evolution of GPS technology and developments on energy harvesting, duty-cycle and sensor fusion techniques, to reduce the power consumption and increase device's autonomy, the impact of GPS location is still very relevant. One alternative that we consider interesting for animal monitoring, is the use of RSSI. As it is present on most Radio Frequency (RF) technologies, its deployment would reduce energy consumption and contribute to the reduction of the cost and size of the hardware, which are key factors. Such use is reported on [PERSON] et al. [60] and [PERSON] et al. [61], when applied to cattle location monitoring. Despite being an attractive solution, these works revealed a still significant immaturity of this kind of solutions, particularly concerning the lack of precision. Thus, there is still an open research opportunity in this area. Despite not being addressed in the scope of this paper, it is a goal of the SheepIIT project, and thus, it was taken into account in the design of the solution. Concerning the behaviour and activity monitoring, the most usual automated approaches are based on accelerometry and audiometry. Tri-axial accelerometers allow measurement of both static and dynamic accelerations, which, after being combined, processed and analyzed, permit to distinguish different kinds of animal behaviours and activities.