Oscar Alvear

Dr. Oscar Alvear

Universidad de Cuenca
orcid

Research Focus & Metrics

Academic Career Length

13Years (2014-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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1 January 2017 in Journal of Advanced Transportation
Verified
Journal Article
Open access
PDF file
OAOscar Alvear
Oscar Alvear
NZNicola Roberto Zema
Nicola Roberto Zema
Enrico NatalizioEnrico Natalizio
Enrico Natalizio
Carlos T. CalafateCarlos T. Calafate
Carlos T. Calafate
Air pollution monitoring has recently become an issue of utmost importance in our society. Despite the fact that crowdsensing approaches could be an adequate solution for urban areas, they cannot be implemented in rural environments. Instead, deploying a fleet of UAVs could be considered an acceptable alternative. Embracing this approach, this paper proposes the use of UAVs equipped with off-the-shelf sensors to perform air pollution monitoring tasks. These UAVs are guided by our proposed Pollution-driven UAV Control (PdUC) algorithm, which is based on a chemotaxis metaheuristic and a local particle swarm optimization strategy. Together, they allow automatically performing the monitoring of a specified area using UAVs. Experimental results show that, when using PdUC, an implicit priority guides the construction of pollution maps by focusing on areas where the pollutants’ concentration is higher. This way, accurate maps can be constructed in a faster manner when compared to other strategies. The PdUC scheme is compared against various standard mobility models through simulation, showing that it achieves better performance. In particular, it is able to find the most polluted areas with more accuracy and provides a higher coverage within the time bounds defined by the UAV flight time.

4 February 2018 in Sensors
Verified
Journal Article
Open access
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OAOscar Alvear
Oscar Alvear
Carlos T. CalafateCarlos T. Calafate
Carlos T. Calafate
Juan-Carlos CanoJuan-Carlos Cano
Juan-Carlos Cano
Pietro ManzoniPietro Manzoni
Pietro Manzoni
Evidence shows that Smart Cities are starting to materialise in our lives through the gradual introduction of the Internet of Things (IoT) paradigm. In this scope, crowdsensing emerges as a powerful solution to address environmental monitoring, allowing to control air pollution levels in crowded urban areas in a distributed, collaborative, inexpensive and accurate manner. However, even though technology is already available, such environmental sensing devices have not yet reached consumers. In this paper, we present an analysis of candidate technologies for crowdsensing architectures, along with the requirements for empowering users with air monitoring capabilities. Specifically, we start by providing an overview of the most relevant IoT architectures and protocols. Then, we present the general design of an off-the-shelf mobile environmental sensor able to cope with air quality monitoring requirements; we explore different hardware options to develop the desired sensing unit using readily available devices, discussing the main technical issues associated with each option, thereby opening new opportunities in terms of environmental monitoring programs.

28 May 2018 in Mobile Networks and Applications
Verified
Journal Article
Open access
PDF file
OAOscar Alvear
Oscar Alvear
CCCarlos T. Calafate
Carlos T. Calafate
NZNicola Roberto Zema
Nicola Roberto Zema
ENEnrico Natalizio
Enrico Natalizio
EHEnrique Hernández-Orallo
Enrique Hernández-Orallo
Pietro ManzoniPietro Manzoni
Pietro Manzoni
Recently, Unmanned Aerial Vehicles (UAVs) have become a cheap alternative to sense pollution values in a certain area due to their flexibility and ability to carry small sensing units. In a previous work, we proposed a solution, called Pollution-driven UAV Control (PdUC), to allow UAVs to autonomously trace pollutant sources, and monitor air quality in the surrounding area. However, despite operational, we found that the proposed solution consumed excessive time, especially when considering the battery lifetime of current multi-rotor UAVs. In this paper, we have improved our previously proposed solution by adopting a space discretization technique. Discretization is one of the most efficient mathematical approaches to optimize a system by transforming a continuous domain into its discrete counterpart. The improvement proposed in this paper, called PdUC-Discretized (PdUC-D), consists of an optimization whereby UAVs only move between the central tile positions of a discretized space, avoiding monitoring locations separated by small distances, and whose actual differences in terms of air quality are barely noticeable. We also analyze the impact of varying the tile size on the overall process, showing that smaller tile sizes offer high accuracy at the cost of an increased flight time. Taking into account the obtained results, we consider that a tile size of 100 × 100 meters offers an adequate trade-off between flight time and monitoring accuracy. Experimental results show that PdUC-D drastically reduces the convergence time compared to the original PdUC proposal without loss of accuracy, and it also increases the performance gap with standard mobility patterns such as Spiral and Billiard.

11 December 2015
Verified
Conference Paper
Open access
OAOscar Alvear
Oscar Alvear
CCCarlos T. Calafate
Carlos T. Calafate
EHEnrique Hernández
Enrique Hernández
JCJuan-Carlos Cano
Juan-Carlos Cano
Pietro ManzoniPietro Manzoni
Pietro Manzoni
Nowadays, the impact of global warming is causing societies to become more aware and responsive to environmental problems. As a result, pollution sensing is gaining more relevance. In order to have a strict control over air quality, the use of mobile sensors is becoming a promising alternative to traditional air quality stations. Mobile sensors allow to easily perform measurements in many different places, thereby offering substantial improvements in terms of the spatial granularity of the data gathered. Pollution monitoring near large industrial areas or in rural areas where transportation facilities are poor or inexistent can complicate the mobile sensing approach. To address this problem, in this paper we propose endowing Unmanned Aerial Vehicles (UAVs) with pollution sensors, allowing them to become autonomous air monitoring stations. The proposed solution has the potential to quickly cover a target region at a low cost, and providing great flexibility.

1 June 2016
Verified
Conference Paper
Closed access
OAOscar Alvear
Oscar Alvear
WMWillian Jesus Zamora Mero
Willian Jesus Zamora Mero
CCCarlos T. Calafate
Carlos T. Calafate
JCJuan-Carlos Cano
Juan-Carlos Cano
Pietro ManzoniPietro Manzoni
Pietro Manzoni
Air pollution monitoring has become an essential requirement for cities worldwide. Currently, the most extended way to monitor air pollution is via fixed monitoring stations, which are expensive and hard to install. To solve this problem, we have developed EcoSensor, a solution to monitor air pollution through mobile sensors. It is deployed with off-the-shelf hardware such as Waspmote (based on the Arduino platform), low-end sensors, and Raspberry Pi devices.

14 April 2016 in Journal of Sensors
Verified
Journal Article
Open access
PDF file
OAOscar Alvear
Oscar Alvear
WMWillian Jesus Zamora Mero
Willian Jesus Zamora Mero
Carlos T. CalafateCarlos T. Calafate
Carlos T. Calafate
JCJuan-Carlos Cano
Juan-Carlos Cano
Pietro ManzoniPietro Manzoni
Pietro Manzoni
Mobile sensing is becoming the best option to monitor our environment due to its ease of use, high flexibility, and low price. In this paper, we present a mobile sensing architecture able to monitor different pollutants using low-end sensors. Although the proposed solution can be deployed everywhere, it becomes especially meaningful in crowded cities where pollution values are often high, being of great concern to both population and authorities. Our architecture is composed of three different modules: a mobile sensor for monitoring environment pollutants, an Android-based device for transferring the gathered data to a central server, and a central processing server for analyzing the pollution distribution. Moreover, we analyze different issues related to the monitoring process: (i) filtering captured data to reduce the variability of consecutive measurements; (ii) converting the sensor output to actual pollution levels; (iii) reducing the temporal variations produced by mobile sensing process; and (iv) applying interpolation techniques for creating detailed pollution maps. In addition, we study the best strategy to use mobile sensors by first determining the influence of sensor orientation on the captured values and then analyzing the influence of time and space sampling in the interpolation process.