Managing Mobility for Distributed Smart Cities Services

The IoT refers to the idea of internetworking physical devices, vehicles, buildings, and any other item embedded with the appropriate electronics, software, sensors, actuators, and network connectivity to allows them to interchange data and to provide highly effective new services. In this thesis we focus on the communications issues of the IoT in relation to mobility and we provide different solutions to alleviate the impact of these potential problems and to guarantee the information delivery in mobile scenarios. Our reference context is a Smart City where various mobile devices collaboratively participate, periodically sending information from their sensors. We assume that these services are located in platforms based in cloud infrastructures where the information is protected through the use of virtualisation ensuring their security and privacy. This thesis is structured into seven chapters. We first detail our objectives and identify the current problems we intend to address. Next, we provide a thorough review of the state of the art of all the areas involved in our work, highlighting how we improved the existing solutions with our research. The overall approach of the solutions we propose in this thesis use prototypes that encompasses and integrates different technologies and standards in a small infrastructure, using real devices in real scenarios with two of the most commonly used networks around the world: WiFi and 802.15.4 to efficiently solve the problems we originally identified. We focussed on protocols based on a producer/consumer paradigm, namely AMQP and particularly MQTT. We observed the behaviour of these protocols using in lab experiments and in external environments, using a mesh wireless network as the backbone network. Various issues raised by mobility were taken into consideration, and thus, we repeated the tests with different messages sizes and different inter-message periodicity, in order to model different possible applications. We also present a model for dimensioning the number of sources for mobile nodes and calculating the number of buffers required in the mobile node as a function of the number of sources and the size of the messages. We included a mechanism for avoiding data loss based on intermediate buffering adapted to the MQTT protocol that, in conjunction with the use of an alternative to the Network Manager in certain contexts, improves the connection establishment for wireless mobile clients. We also performed a detailed study of the jitter behaviour of a mobile node when transmitting messages with this proposal while moving through a real outdoor scenario. To emulate simple IoT networks we used the Cooja simulator to study and determine the effects on the probability of delivering messages when both publishers and subscribers were added to different scenarios. Finally we present an approach that combines the MQTT protocol with DTN which we specifically designed for constrained environments and guarantees that important information will never be lost. The advantage of our proposed solutions is that they make an IoT system more resilient to changes in the point of attachment of the mobile devices in an IoT network without requiring IoT application & service developers to explicitly consider this issue. Moreover, our solutions do not require additional support from the network through protocols such as MobileIP or LISP. We close the thesis by providing some conclusions, and identifying future lines of work which we unable to address here.Internet de las cosas (IoT) se refiere a la idea de interconectar sensores, actuadores, dispositivos físicos, vehículos, edificios y cualquier elemento dotado de la electrónica, así como del software y de la conectividad de red que los hace capaces de intercambiar datos para proporcionar servicios altamente efectivos. En esta tesis nos centramos en temas relacionados con la comunicación de sistemas IoT, específicamente en situaciones de movilidad y en los problemas que esto conlleva. Con este fin ofrecemos diferentes soluciones que alivian su impacto y garantizan la entrega de información en estas situaciones. El contexto de referencia es una ciudad inteligente donde varios dispositivos móviles participan de forma colaborativa enviando periódicamente información desde sus sensores hacia servicios ubicados en plataformas en la nube (cloud computing) donde mediante el uso de virtualización, la información está protegida garantizando su seguridad y privacidad. Las soluciones propuestas en esta tesis se enfocan en probar sobre una pequeña infraestructura un prototipo que abarca e integra diferentes tecnologías y estándares para resolver eficientemente los problemas previamente identificados. Hemos enfocado nuestro esfuerzo en el uso de dispositivos sobre escenarios reales con dos de las redes más extendidas en todo el mundo: WiFi y enlaces 802.15.4. Nos enfocamos en protocolos que ofrecen el paradigma productor/consumidor como el protocolo avanzado de colas de mensajes (AMQP) y particularmente el protocolo de transporte de mensajes telemétricos (MQTT), observamos su comportamiento a través de experimentos en laboratorio y en pruebas al aire libre, repitiendo las pruebas con diferentes tamaños de mensajes y diferente periodicidad entre mensajes. Para modelar las diferentes posibles aplicaciones de la propuesta, se tomaron en consideración varias cuestiones planteadas por la movilidad, resultando en un modelo para dimensionar eficientemente el número de fuentes para un nodo móvil y para calcular el tamaño requerido del buffer, en función del número de fuentes y del tamaño de los mensajes. Proponemos un mecanismo adaptado al protocolo MQTT que evita la pérdida de datos en clientes móviles, basado en un buffer intermedio entre la producción y publicación de mensajes que, en conjunto con el uso de una alternativa al gestor de conexiones inalámbricas "Network Manager", en ciertos contextos mejora el establecimiento de las conexiones. Para la evaluación de esta propuesta se presenta un estudio detallado de un nodo móvil que se mueve en un escenario real al aire libre, donde estudiamos el comportamiento del jitter y la transmisión de mensajes. Además, hemos utilizado emuladores de redes IoT para estudiar y determinar los efectos sobre la probabilidad de entrega de mensajes, cuando se agregan tanto publicadores como suscriptores a diferentes escenarios. Finalmente, se presenta una solución totalmente orientada a entornos con dispositivos de recursos limitados que combina los protocolos MQTT con redes tolerantes a retardos (DTN) para garantizar la entrega de información. La ventaja de las soluciones que proponemos reside en el hecho de que los sistemas IoT se vuelven resilientes a la movilidad y a los cambios de punto de acceso, permitiendo así que los desarrolladores creen fácilmente aplicaciones y servicios IoT evitando considerar estos problema. Otra ventaja de nuestras soluciones es que no necesitan soporte adicional de la red como sucede con protocolos como MobileIP o el protocolo que separa el identificador del localizador (LISP). Se destaca cómo hemos mejorado las soluciones existentes hasta el momento de la escritura de esta disertación, y se identifican futuras líneas de actuación que no han sido contempladas.Internet de les coses (IoT) es refereix a la idea d'interconnectar sensors, actuadors, dispositius físics, vehicles, edificis i qualsevol element dotat de l'electrònica, així com del programari i de la connectivitat de xarxa que els fa capaces d'intercanviar dades per proporcionar serveis altament efectius. En aquesta tesi ens centrem en temes relacionats amb la comunicació de sistemes IoT, específicament en situacions de mobilitat i en els problemes que això comporta. A aquest efecte oferim diferents solucions que alleugeren el seu impacte i garanteixen el lliurament d'informació en aquestes situacions. El context de referència és una ciutat intel·ligent on diversos dispositius mòbils participen de forma col·laborativa enviant periòdicament informació des dels seus sensors cap a serveis situats en plataformes en el núvol (cloud computing) on mitjançant l'ús de virtualització, la informació està protegida garantint la seva seguretat i privadesa. Les solucions proposades en aquesta tesi s'enfoquen a provar sobre una xicoteta infraestructura un prototip que abasta i integra diferents tecnologies i estàndards per a resoldre eficientment els problemes prèviament identificats. Hem enfocat el nostre esforç en l'ús de dispositius sobre escenaris reals amb dos de les xarxes més esteses a tot el món: WiFi i enllaços 802.15.4. Ens enfoquem en protocols que ofereixen el paradigma productor/consumidor com el protocol avançat de cues de missatges (AMQP) i particularment el protocol de transport de missatges telemètrics (MQTT), observem el seu comportament a través d'experiments en laboratori i en proves a l'aire lliure, repetint les proves amb diferents grandàries de missatges i diferent periodicitat entre missatges. Per a modelar les diferents possibles aplicacions de la proposta, es van prendre en consideració diverses qüestions plantejades per la mobilitat, resultant en un model per a dimensionar eficientment el nombre de fonts per a un node mòbil i per a calcular la grandària requerida del buffer, en funció del nombre de fonts i de la grandària dels missatges. Proposem un mecanisme adaptat al protocol MQTT que evita la pèrdua de dades per a clients mòbils, basat en un buffer intermedi entre la producció i publicació de missatges que en conjunt amb l'ús d'una alternativa al gestor de connexions sense fils "Network Manager'', en certs contextos millora l'establiment de les connexions. Per a l'avaluació d'aquesta proposta es presenta un estudi detallat d'un node mòbil que es mou en un escenari real a l'aire lliure, on estudiem el comportament del jitter i la transmissió de missatges. A més, hem utilitzat emuladors de xarxes IoT per a estudiar i determinar els efectes sobre la probabilitat de lliurament de missatges, quan s'agreguen tant publicadors com subscriptors a diferents escenaris. Finalment, es presenta una solució totalment orientada a entorns amb dispositius de recursos limitats que combina els protocols MQTT amb xarxes tolerants a retards (DTN) per a garantir el lliurament d'informació. L'avantatge de les solucions que proposem resideix en el fet que els sistemes IoT es tornen resilients a la mobilitat i als canvis de punt d'accés, permetent així que els desenvolupadors creuen fàcilment aplicacions i serveis IoT evitant considerar aquests problema. Un altre avantatge de les nostres solucions és que no necessiten suport addicional de la xarxa com succeeix amb protocols com MobileIP o el protocol que separa l'identificador del localitzador (LISP). Es destaca com hem millorat les solucions existents fins al moment de l'escriptura d'aquesta dissertació, i s'identifican futures línies d'actuació que no han sigut contemplades.Luzuriaga Quichimbo, JE. (2017). Managing Mobility for Distributed Smart Cities Services [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/84744TESI

Descarga de computación de dispositivos móviles a ambientes Cloud Computing en un caso en concreto, el reconocimiento facial

[ES] Beneficios en la descarga de computación con una aplicación de reconocimiento facial para dispositivos móviles hacia un entorno Cloud Computing con el Reconocimiento como Servicio. Se mide prestaciones en ambos plataformas y se busca un escenario colaborativo que ofresca un equilibrio entre los procesos inmersos en este contexto.[EN] Benefits in computation offloading with a facial recognition application for mobile devices to Cloud Computing environment with the Recognition as a Service. The performance is measured on both platforms and we looking a collaborative setting to permit a balance between the processes involved in this contextLuzuriaga Quichimbo, JE. (2012). Descarga de computación de dispositivos móviles a ambientes Cloud Computing en un caso en concreto, el reconocimiento facial. http://hdl.handle.net/10251/17873Archivo delegad

Handling Mobility in IoT applications based on the MQTT protocol

© 2015 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.Connectivity clearly plays an important role in Internet of Things (loT) solutions, and the efficient handling of mobility is crucial for the overall performance of loT applications. Currently, the most widely adopted protocols for loT and Machine to Machine (M2M) environments, namely MQTT, CoAP or LWM2M, are directly dependent on the TCP/IP protocol suite. This suite is highly reliable when using wired networks, but it is not the best solution in the presence of intermittent connections. In this work we provide a solution to improve MQTT with an emphasis on mobile scenarios. The advantage of the solution we propose is making the system more immune to changes in the point of attachment of mobile devices. This way we avoid loT service developers having to explicitly consider this issue. Moreover, our solution does not need extra support from the network through protocols like MobilelP or LISP. The obtained results show that our proposal, based on intermediate buffering, guarantees that there is no information loss during hand-off periods due to node mobility; furthermore, based on discrete event simulation results, we determine the maximum number of sources and the required amount of buffers for a mobile node.This work was partially supported by the Ministerio de Economía y Competitividad, Programa Estatal de Investigación, Desarrollo e Innovación Orientada a los Retos de la Sociedad, Proyectos I+D+I 2014, Spain, under Grant TEC2014-52690-R.Luzuriaga Quichimbo, JE.; Cano Escribá, JC.; Tavares De Araujo Cesariny Calafate, CM.; Manzoni, P.; Perez, M.; Boronat, P. (2015). Handling Mobility in IoT applications based on the MQTT protocol. IEEE. https://doi.org/10.1109/ITechA.2015.7317403

Impact of mobility on Message Oriented Middleware (MOM) protocols for collaboration in transportation

© 2015 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.Message Oriented Middleware (MOM) refers to the software infrastructure that support ubiquitous information delivery among software and hardware systems. Two of the most relevant protocols in this context are AMQP and MQTT. Lately, they have been extensively used to exchange messages conserving network bandwidth, device memory and batteries. These protocols provide an abstraction of the communication programming details of the different participating system entities, alleviating their coordination and collaboration. However, these protocols have not been thoroughly tested focused on studying the impact of node mobility. In this paper we present an experimental evaluation of both protocols quantifying the effect of the node mobility in terms of message loss, latency, jitter and saturation boundary values. Based on the results obtained, we provide criteria of applicability of these protocols. This evaluation is of interest for the upcoming applications that can be supported by MOM, and in especial for communication in Machine to Machine (M2M) and Internet of Things (IoT).This work was partially supported by the Ministerio de Ciencia e Innovación, Spain, under Grant TIN2011-27543-C03-01.Luzuriaga Quichimbo, JE.; Pérez, M.; Boronat, P.; Cano Escribá, JC.; Tavares De Araujo Cesariny Calafate, CM.; Manzoni, P. (2015). Impact of mobility on Message Oriented Middleware (MOM) protocols for collaboration in transportation. IEEE. https://doi.org/10.1109/CSCWD.2015.7230943

A comparative evaluation of AMQP and MQTT protocols over unstable and mobile networks

© 2015 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.Message oriented middleware (MOM) refers to the software infrastructure supporting sending and receiving messages between distributed systems. AMQP and MQTT are the two most relevant protocols in this context. They are extensively used for exchanging messages since they provide an abstraction of the different participating system entities, alleviating their coordination and simplifying the communication programming details. These protocols, however, have not been thoroughly tested in the context of mobile or dynamic networks like vehicular networks. In this paper we present an experimental evaluation of both protocols in such scenarios, characterizing their behavior in terms of message loss, latency, jitter and saturation boundary values. Based on the results obtained, we provide criteria of applicability of these protocols, and we assess their performance and viability. This evaluation is of interest for the upcoming applications of MOM, especially to systems related to the Internet of Things.This work was partially supported by the Ministerio de Ciencia e Innovación, Spain, under Grant TIN2011-27543-C03-01.Luzuriaga Quichimbo, JE.; Pérez, M.; Boronat, P.; Cano Escribá, JC.; Tavares De Araujo Cesariny Calafate, CM.; Manzoni, P. (2015). A comparative evaluation of AMQP and MQTT protocols over unstable and mobile networks. IEEE. https://doi.org/10.1109/CCNC.2015.7158101

Evaluating computation offloading tradeoffs in mobile cloud computing: a sample application

[EN] Mobile cloud computing is generally referred to as the infrastructure where both the data storage and the data processing happen outside of the mobile device. The nature of the connection between the cloud servers and the mobile host are anyway much less reliable than in classical cloud computing with static devices. A compromise must be found between local versus remote computation so to cope with the reduced performance of the data connection and with the characteristics of the mobile device, basically its power availability limitations. In this paper, we evaluate the tradeoffs of computation offloading using as a case study a facial recognition application for smartphones where recognition is a service in the cloud. We present a specifically designed application for mobile devices developed as a component of the proposed evaluation system. The intensive calculus needed for the image manipulation is compared in terms of speed and accuracy both when we delegate it to cloud computing and when we perform it locally on the mobile device. These two alternatives and the intermediate options are compared to determine the optimal settings to take better advantage of integrating these two technologies.This work was partially supported by the Ministerio de Ciencia e Innovación, Spain, under Grant TIN2011-27543-C03-01.Luzuriaga Quichimbo, JE.; Cano Escribá, JC.; Tavares De Araujo Cesariny Calafate, CM.; Manzoni, P. (2013). Evaluating computation offloading tradeoffs in mobile cloud computing: a sample application. IARIA XPS Press. http://hdl.handle.net/10251/75238

Testing AMQP protocol on unstable and mobile networks

The final publication is available at Springer via http://dx.doi.org/ 10.1007/978-3-319-11692-1_22AMQP is a middleware protocol extensively used for exchanging messages in distributed applications. It provides an abstraction of the different participating parts and simplifies communication programming details. AMQP provides reliability features and alleviates the coordination of different entities of an application. However, implementations of this protocol have not been well tested in the context of mobile or unstable networks. This paper is the starting point of an experimental evaluation of AMQP protocol in such kind of scenarios. Our goal is to identify the limits of applicability of this middleware, assessing its the capacity in terms of message losses, latencies or jitter, when wireless devices are interrupted and reconnected. This evaluation is of interest for the upcoming applications in which personal devices and vehicles will collaborate, forming part of large complex systems.Luzuriaga Quichimbo, JE.; Pérez, M.; Boronat, P.; Cano Escribá, JC.; Tavares De Araujo Cesariny Calafate, CM.; Manzoni, P. (2014). Testing AMQP protocol on unstable and mobile networks. En Internet and Distributed Computing Systems. Springer. 250-260. doi:10.1007/978-3-319-11692-1_22S250260O’Hara, J.: Toward a Commodity Enterprise Middleware. Communications Magazine (2007)Gusmeroli, S., Piccione, S., Rotondi, D.: IoT@Work automation middleware system design and architecture. In: IEEE International Conference on Emerging Technologies and Factory Automation, ETFA (2012)Foundation OpenStack. AMQP and Nova (2014)Corporation IMatix. Security and Robustness (2014)Subramoni, H., Marsh, G., Narravula, S., Lai, P., Panda, D.K.: Design and evaluation of benchmarks for financial applications using advanced message queuing protocol (AMQP) over infiniband. In: 2008 Workshop on High Performance Computational Finance, WHPCF 2008 (2008)Appel, S., Sachs, K., Buchmann, A.: Towards benchmarking of amqp. In: Proceedings of the Fourth ACM International Conference on Distributed Event-Based Systems, pp. 99–100. ACM (2010)Fernandes, J.L., Lopes, I.C., Rodrigues, J.J.P.C., Ullah, S.: Performance evaluation of RESTful web services and AMQP protocol. In: IEEE ICUFN, pp. 810–815 (2013)Lee, S., Kim, H., Hong, D.K., Ju, H.: Correlation analysis of MQTT loss and delay according to QoS level. In: International Conference on Information Networking, pp. 714–717 (2013)Inc. Pivotal Software. Messaging that just works (2014

Improving MQTT Data Delivery in Mobile Scenarios:Results from a Realistic Testbed

© 2016 Jorge E. Luzuriaga et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.MQTT is being widely used for data delivery in IoT applications but its architecture does not properly handle mobility when disconnection periods tend to be large. In this paper we describe an experimental evaluation, made in a real environment, of a solution that guarantees that there is no information loss when variable length hand-offs appear due to the movement of a node. Our proposal modifies the classical publish/subscribe scheme by introducing an intermediate buffer that takes care of message transfer. Finally, we study the impact related to the connectivity of mobile devices of the use of the standard Linux Network Manager. We propose a cross-layer solution that improves the device connectivity in conjunction with the data layer management. We show that our solution improves the data delivery guaranteeing that no information is lost.This work was partially supported by Ministerio de Economia y Competitividad, Programa Estatal de Investigacion, Desarrollo e Innovacion Orientada a los Retos de la Sociedad, Proyectos I+D+I 2014, Spain, under Grant TEC2014-52690-R.Luzuriaga-Quichimbo, JE.; Perez, M.; Boronat, P.; Cano Escribá, JC.; Tavares De Araujo Cesariny Calafate, CM.; Manzoni, P. (2016). Improving MQTT Data Delivery in Mobile Scenarios:Results from a Realistic Testbed. Mobile Information Systems. 2016:1-11. https://doi.org/10.1155/2016/4015625S111201

Empowering Youth Employment through European Digital Bootcamps (EDIBO)

[EN] Information and Communication Technologies (ICT) are transforming every area of economic and social life all around the world. New types of jobs different from the traditional ones are created rapidly. The demand for highly skilled staff who uses technology effectively has become a requirement for success of companies and the growing industry. However, the number of IT graduates is not keeping up with the current demand. In addition, companies have little or no training programs to develop ICT skills. Initiatives from the European Economic Area (EEA) and Norway Grants to support transnational projects for Youth Employment including European Digital Bootcamps (EDIBO) contribute to increase the job opportunities for young people outside of the labour market. In this way the Sustainable Development Goal 8 which aims to “promote sustained, inclusive and sustainable economic growth, full and productive employment and decent work for all” could be fulfilled. Nowadays, EDIBO is developing different training labs in order to achieve a success model of all processes involved with the organization, execution and evaluation. The goal of this document is to allow a rapid replication of the intensive ICT training among the partners of the project as well to the social innovation community in general.Luzuriaga Quichimbo, JE.; Mauleón, B.; Ampuero Canellas, O.; Lemus Zúñiga, LG.; Mateo Pla, MÁ.; Benlloch Dualde, JV.; González Del Rio Cogorno, J.... (2019). Empowering Youth Employment through European Digital Bootcamps (EDIBO). En Proceedings 5th CARPE Conference: Horizon Europe and beyond. Editorial Universitat Politècnica de València. 21-28. https://doi.org/10.4995/CARPE2019.2019.10207OCS212