Artificial Neural Networks applied to improve low-cost air quality monitoring precision

It is a fact that air pollution is a major environmental health problem that affects everyone, especially in urban areas. Furthermore, the cost of high-end air pollution monitoring sensors is considerably high, so public administrations are unable to afford to place an elevated number of measuring stations, leading to the loss of information that could be very helpful. Over the last few years, a large number of low-cost sensors have been released, but its use is often problematic, due to their selectivity and precision problems. A calibration process is needed in order to solve an issue with many parameters with no clear relationship among them, which is a field of application of Machine Learning. The objectives of this project are first, integrating three low-cost air quality sensors into a Raspberry Pi and then, training an Artificial Neural Network model that improves precision in the readings made by the sensors.Es un hecho que la contaminación del aire es un gran problema para la salud a nivel mundial, especialmente en zonas urbanas. Además, el coste de los sensores de contaminación de gama alta es considerablemente alto, por lo que los organismos públicos no pueden permitirse emplazar un gran número de estaciones de medida, perdiendo información que podría ser muy útil. A lo largo de los últimos años, han surgido muchos sensores de contaminación de bajo coste, pero su uso suele ser complicado, ya que tienen problemas de selectividad y precisión. Los objetivos de este proyecto son primero integrar tres sensores de contaminación de bajo coste en una Raspberry Pi y sobre todo, entrenar un modelo basado en una red neuronal artificial que mejore la precisión de las lecturas realizadas por los sensores.Està demostrat que la contaminació de l'aire és un gran problema per a la salut a nivell mundial, especialment en zones urbanes. A més, el cost dels sensors de contaminació de gama alta és considerablement alt, motiu pel qual els organismes públics no es poden permetre emplaçar una gran quantitat d'estacions de mesura, perdent informació que podria resultar molt útil. Al llarg dels últims anys, han sorgit molts sensors de contaminació de baix cost, però el seu ús és sovint complicat, ja que tenen problemes de selectivitat i precisió. Els objectius d'aquest projecte són primer de tot integrar tres sensors de contaminació de baix cost en una Raspberry Pi i sobretot, entrenar un model basat en una xarxa neuronal artificial que millori la precisió de les lectures realitzades pels sensors

An Implementation for Dynamic Application Allocation in Shared Sensor Networks

We present a system architecture implementation to perform dynamic application allocation in shared sensor networks, where highly integrated wireless sensor systems are used to support multiple applications. The architecture is based on a central controller that collects the received data from the sensor nodes, dynamically decides which applications must be simultaneously deployed in each node and, accordingly, over-the-air reprograms the sensor nodes. Waspmote devices are used as sensor nodes that communicate with the controller using ZigBee protocol. Experimental results show the viability of the proposal

On reliable and secure RPL (routing protocol low-power and lossy networks) based monitoring and surveillance in oil and gas fields

Different efforts have been made to specify protocols and algorithms for the successful operation of the Internet of things Networks including, for instance, the Low Power and Lossy Networks (LLNs) and Linear Sensor Networks (LSNs). Into such efforts, IETF, the Internet Engineering Task Force, created a working group named, ROLL, to investigate the requirement of such networks and devising more efficient solutions. The effort of this group has resulted in the specification of the IPv6 Routing Protocol for LLNs (RPL), which was standardized in 2012. However, since the introduction of RPL, several studies have reported that it suffers from various limitations and weaknesses including scalability, slow convergence, unfairness of load distribution, inefficiency of bidirectional communication and security, among many others. For instance, a serious problem is RPL’s under-specification of DAO messages which may result in conflict and inefficient implementations leading to a poor performance and scalability issues. Furthermore, RPL has been found to suffer from several security issues including, for instance, the DAO flooding attack, in which the attacker floods the network with control messages aiming to exhaust network resources. Another fundamental issue is related to the scarcity of the studies that investigate RPL suitability for Linear Sensor Networks (LSN) and devising solution in the lieu of that.Motivated by these observations, the publications within this thesis aim to tackle some of the key gaps of the RPL by introducing more efficient and secure routing solutions in consideration of the specific requirements of LLNs in general and LSNs as a special case. To this end, the first publication proposes an enhanced version of RPL called Enhanced-RPL aimed at mitigating the memory overflow and the under-specification of the of DAOs messages. Enhanced-RPL has shown significant reduction in control messages overhead by up to 64% while maintaining comparable reliability to RPL. The second publication introduces a new technique to address the DAO attack of RPL which has been shown to be effective in mitigating the attack reducing the DAO overhead and latency by up to 205% and 181% respectively as well as increasing the PDR by up to 6% latency. The third and fourth publications focus on analysing the optimal placement of nodes and sink movement pattern (fixed or mobile) that RPL should adopt in LSNs. It was concluded based on the results obtained that RPL should opt for fixed sinks with 10 m distance between deployed nodes

Data redundancy reduction for energy-efficiency in wireless sensor networks: a comprehensive review

Wireless Sensor Networks (WSNs) play a significant role in providing an extraordinary infrastructure for monitoring environmental variations such as climate change, volcanoes, and other natural disasters. In a hostile environment, sensors' energy is one of the crucial concerns in collecting and analyzing accurate data. However, various environmental conditions, short-distance adjacent devices, and extreme usage of resources, i.e., battery power in WSNs, lead to a high possibility of redundant data. Accordingly, the reduction in redundant data is required for both resources and accurate information. In this context, this paper presents a comprehensive review of the existing energy-efficient data redundancy reduction schemes with their benefits and limitations for WSNs. The entire concept of data redundancy reduction is classified into three levels, which are node, cluster head, and sink. Additionally, this paper highlights existing key issues and challenges and suggested future work in reducing data redundancy for future research