## 2 Related Work
### IoT Applications  
A typical IoT application is a smart house where the refrigerator can report the current status of the food; the temperature of each room sets according to the preferences of the people occupying such space; and all devices working on identifying possible catastrophes such as a gas leak.  
Another application is a smart campus which can use the new generation of information technology such as IoT, cloud computing, and big data to perceive, store, manage, and analyze all the key information of campus system; all of these can serve, for example, to save energy and assisting the staff such as faculty, students and administrative in decision making [7].  
The evolution of IoT, starting from smart house, through smart campus and joining with other technologies such as big data, data analysis, among others, have paved the way to smart cities. This concept brings a bigger picture from the houses into a whole city where public transportation, energy, water supply, and environmental factors are at stake.  
For example, there is a large number of different devices designed for IoT, but also modern smartphones can work since they include multiple sensors, communication standards, and can store data. The authors in [8], have looked at a different perspective by using smartphones to create the next generation of civil infrastructure monitoring systems. However, [PERSON] et al. [9], have identified that there are not enough tools to design the cities of the future. Therefore, they created InterSCity, which is a smart city platform that focuses on collaborative development of services, applications, and systems. Unfortunately, it is complex and requires a lot of time and a large budget to do enough testing to actually identify opportunities.  
Consequently, researchers are now focusing on working on smart campuses, which is a bridgework between smart homes and cities.  
A campus is large enough to provide challenges related to device positioning and at the same time it allows a safe environment to collect data from the parking lot, the usage of rooms, the amount of water and electrical energy during the day and monitor other aspects as well.  
Thus, the authors in [10] used an agent-based computing paradigm to gather data from their smart university campus where they could test communication issues and solve them as a decentralized system.  
Another example is [7] where key data is stored and analyzed to provide useful information to teachers, students, and staff. Monitoring a classroom to identify how much time is used and by how many people, can help take better decisions on how to assign classrooms to different groups in such a way that it is optimized.  
[PERSON] et al. [11] have mainly focused on profiling energy usage in campus buildings, setting power distribution system architecture, and pinpointing key micro-grid components. They propose a general Microgrid (MG) testbed and simulate the operation of proposed MG model/architecture. They delineate relevant pros and cons towards a futuristic real-world/physical MG deployment in a university campus.  
IoT is gaining a special moment and the application in smart campuses (respectively smart cities) requires essential technologies for the deployment of successful products and services as described by [PERSON] and [PERSON] [12]. Such essential technologies are:  
1. Radio frequency identification (RFID);
2. Middleware;
3. IoT software application;
4. Cloud computing; and
5. Wireless sensor networks (WSN).  
In the following subsections we put our attention in WSN.