Actuellement, des descriptions basées sur de simples schémas XML sont utilisées pour décrire un capteur/actuateur et les données qu’il mesure et fournit. Ces schémas sont généralement formalisés en utilisant le langage SensorML (Sensor Model Language), ne permettant qu’une description hiérarchique basique des attributs des objets sans aucune notion de liens sémantiques, de concepts et de relations entre concepts. Nous pensons au contraire que des descriptions sémantiques des capteurs/actuateurs sont nécessaires au design et à la mise en œuvre de mécanismes efficaces d’inférence, de fusion et de composition de données. Cette ontologie sémantique permettra de masquer l’hétérogénéité des données collectées et facilitera leur fusion et leur composition au sein d’un environnement de gestion de capteur similaire à celui d’une architecture ouverte orientée services. La première partie des travaux de cette thèse porte donc sur la conception et la validation d’une ontologie sémantique légère, extensible et générique de description des données fournies par un capteur/actuateur. Cette description ontologique de données brutes devra être conçue : • d’une manière extensible et légère afin d’être applicable à des équipements embarqués hétérogènes, • comme sous élément d’une ontologie de plus haut niveau (upper level ontology) utilisée pour modéliser les capteurs et actuateurs (en tant qu’équipements et non plus de données fournies), ainsi que les informations mesurées (information veut dire ici donnée de plus haut niveau issue du traitement et de la fusion des données brutes). La seconde partie des travaux de cette thèse portera sur la spécification et la qualification : • d’une architecture générique orientée service (SOA) permettant la découverte et la gestion d’un capteur/actuateur, et des données qu’il fournit (incluant leurs agrégation et fusion en s’appuyant sur les mécanismes de composition de services de l’architecture SOA), à l’identique d’un service composite de plus haut niveau, • d’un mécanisme amélioré de collecte de données à grande échelle, au dessus de cette ontologie descriptive. L’objectif des travaux de la thèse est de fournir des facilitateurs permettant une mise en œuvre de mécanismes efficaces de collecte, de fusion et d’agrégation de données, et par extension de prise de décisions. L’ontologie de haut niveau proposée sera quant à elle pourvue de tous les attributs permettant une représentation, une gestion et une composition des ‘capteurs, actuateurs et objets’ basées sur des architectures orientées services (Service Oriented Architecture ou SOA). Cette ontologie devrait aussi permettre la prise en compte de l’information transporter (sémantique) dans les mécanismes de routage (i.e. routage basé information). Les aspects liés à l’optimisation et à la modélisation constitueront aussi une des composantes fortes de cette thèse. Les problématiques à résoudre pourraient être notamment : • La proposition du langage de description le mieux adapté (compromis entre richesse, complexité et flexibilité), • La définition de la structure optimum de l’architecture de découverte et de gestion d’un capteur/actuateur, • L’identification d’une solution optimum au problème de la collecte à grande échelle des données de capteurs/actuateurs / The constant evolution of technology in terms of inexpensive and embedded wireless interfaces and powerful chipsets has leads to the massive usage and development of wireless sensor networks (WSNs). This potentially affects all aspects of our lives ranging from home automation (e.g. Smart Buildings), passing through e-Health applications, environmental observations and broadcasting, food sustainability, energy management and Smart Grids, military services to many other applications. WSNs are formed of an increasing number of sensor/actuator/relay/sink devices, generally self-organized in clusters and domain dedicated, that are provided by an increasing number of manufacturers, which leads to interoperability problems (e.g., heterogeneous interfaces and/or grounding, heterogeneous descriptions, profiles, models …). Moreover, these networks are generally implemented as vertical solutions not able to interoperate with each other. The data provided by these WSNs are also very heterogeneous because they are coming from sensing nodes with various abilities (e.g., different sensing ranges, formats, coding schemes …). To tackle this heterogeneity and interoperability problems, these WSNs’ nodes, as well as the data sensed and/or transmitted, need to be consistently and formally represented and managed through suitable abstraction techniques and generic information models. Therefore, an explicit semantic to every terminology should be assigned and an open data model dedicated for WSNs should be introduced. SensorML, proposed by OGC in 2010, has been considered an essential step toward data modeling specification in WSNs. Nevertheless, it is based on XML schema only permitting basic hierarchical description of the data, hence neglecting any semantic representation. Furthermore, most of the researches that have used semantic techniques for developing their data models are only focused on modeling merely sensors and actuators (this is e.g. the case of SSN-XG). Other researches dealt with data provided by WSNs, but without modelling the data type, quality and states (like e.g. OntoSensor). That is why the main aim of this thesis is to specify and formalize an open data model for WSNs in order to mask the aforementioned heterogeneity and interoperability between different systems and applications. This model will also facilitate the data fusion and aggregation through an open management architecture like environment as, for example, a service oriented one. This thesis can thus be split into two main objectives: 1)To formalize a semantic open data model for generically describing a WSN, sensors/actuators and their corresponding data. This model should be light enough to respect the low power and thus low energy limitation of such network, generic for enabling the description of the wide variety of WSNs, and extensible in a way that it can be modified and adapted based on the application. 2)To propose an upper service model and standardized enablers for enhancing sensor/actuator discovery, data fusion, data aggregation and WSN control and management. These service layer enablers will be used for improving the data collection in a large scale network and will facilitate the implementation of more efficient routing protocols, as well as decision making mechanisms in WSNs

The purpose of this thesis is to investigate the impact on latency and power consumption of certain usage environments for selected communication protocols that have been designed for resource constrained usage. The research questions in this thesis is based on the findings in Lindén report “A latency comparison of IoT protocols in MES” and seeks to answer the following: ”How does MQTT impact the latency and power consumption on a constrained device?” ”How does CoAP impact the latency and power consumption on a constrained device?” ”How does usage environment influence the latency for MQTT and CoAP?” This thesis only seeks to explore concepts and usage environments related to wireless sensor networks, internet of things and constrained devices. The experiments have been carried out on a ESP WROOM 32 Core board V2 applying MQTT and CoAP as the communication protocols. The overall research method used in this thesis is the experimental research design proposed by Wohlin et al. Experiments have been created to support or disprove hypotheses which are formulated to answer the research questions. The experiments were conducted in test environments, which mimic a real-life wireless sensor network environment. The process is thoroughly recorded to further increase the traceability of this thesis. This decision was made due to a comment Boyle et al. made about the problems with real-life experiments about the wireless communication-based research domain. Where Boyle et al. states that there is “insufficient knowledge” available for the research community. The MQTT related latency experiments showed that QoS level 0 had the lowest latency of all the QoS levels. However, the results also showed that QoS 1 and 2 almost had an identical latency. The CoAP related latency experiments did not indicate any obvious trends. The results from the power consumption related experiments were inconclusive since the data was incomplete. The usage environment related experiments yielded conclusive results. The data showed that there was a small variation in the latency impact across the various usage environments. Furthermore, the data suggest that CoAP and MQTT had lower latencies in a high signal strength environment compared to a lower signal strength environment. However, it is not clear if there were any unknown factors influencing the results.

The recent development of wired and wireless communication technologiesmake building automation the next battlefield of the Internet of Things. Multiplestandards have been drafted to accommodate the complex environmentand minimize the resource consumption of wireless sensor networks. This MasterThesis presents a thorough experimental evaluation with the latest Contikinetwork stack and TI CC2650 platform of network performance indicators,including signal coverage, round trip time, packet delivery ratio and powerconsumption. The Master Thesis also provides a comparison of the networkprotocols for low power operations, the existing operating systems for wirelesssensor networks, and the chips that operate on various network protocols. Theresults show that CC2650 is a promising competitor for future development inthe market of building automation.

As the number of Internet of Things devices is increasing rapidly, it is of utmost significance that the implementations of protocols for constrained devices are bug-free. In general implementations of network protocols are error-prone due to their complex nature and ambiguities in the protocol specification. Implementations of network protocols often contain critical errors which could be exploited. To avoid bugs and vulnerabilities, the implementation of network protocols has to adhere to their specifications. The objective of this thesis is to use symbolic execution to test one implementation of the Ephemeral Diffie-Hellman Over COSE (EDHOC) protocol and one implementation of the Constrained Application Protocol (CoAP) against their specifications. The goal is to identify bugs such as crashes, non-conformances, memory errors, and security vulnerabilities that may occur if the implementations are not adhering to their specifications. The methodology to do this consists of three steps: 1) extracting requirements from the protocols Request For Comments and expressing them as formulas, 2) preparing the system under test for symbolic execution and applying the formulas during symbolic execution to detect any paths that violate a requirement, 3) for every path which violates a requirement, the concrete value that the symbolic execution engine provided is used in the unmodified implementation to validate the bug. In total seven non-conformances were found which have been reported to developers. One non-conformance was found in the EDHOC implementation and six were found in the CoAP implementation. / Eftersom antalet Internet of Things enheter ökar snabbt är det av yttersta vikt att imple-menteringarna av nätverksprotokoll för Internet of Things enheter är korrekta. Generellt sett är implementeringar av nätverksprotokoll felbenägna på grund av deras komplexa natur och oklarheter i protokollspecifikationen. Implementeringar av nätverksprotokoll innehåller ofta kritiska buggar som kan utnyttjas. För att undvika buggar och sårbarheter måste implementeringar av nätverksprotokoll följa sina specifikationer. Målet med detta examensarbete är att använda symbolisk exekvering för att testa en implementation av protokollet Ephemeral Diffie-Hellman Over COSE ( EDHOC ) och en implementation av protokollet Constrained Application Protocol (CoAP) mot deras specifikationer. Syftet är att identifiera buggar såsom krascher, icke-konformiteter, minnesfel och säker-hetssårbarheter som kan uppstå om implementeringarna inte följer sina specifikationer. Metodiken för att uppnå detta består av tre steg: 1) extrahera krav från protokollensspecifikationer och uttrycka dem som formler, 2) förbereda systemet som ska testas försymbolisk exekvering och tillämpa formlerna under symbolisk exekvering för att upp-täcka eventuella vägar som bryter mot ett krav, 3) för varje väg som bryter mot ett krav används det konkreta värde som den symboliska exekveringsmotorn tillhandahåller i den oförändrade implementationen för att validera buggen. Totalt sett hittades sju icke-konformiteter. En icke-konformitet hittades i EDHOC implementeringen och sex hittades i CoAP implementeringen.

The Internet is one of the greatest innovations ever created by mankind, and it is a technical trend that has moved into industries to facilitate automation, supervision and management in the form of IoT devices. These devices are designed to be extremely lightweight and operate in low-power and lossy networks, and therefore run a low duty cycle and CPU-clock frequency to reserve battery life. Fog nodes are located on site to minimize network delay and provide centralized processing to handle data from hundreds of connected devices in wireless sensor networks. This is the future of industrial automation. Our goal is to show the functionality of an industrial IoT network within the scope of Fog computing by implementing a closed-loop control system in Cooja. Performance evaluations considered network reliability in terms of packet delivery ratio and timeliness. We assume that wireless IoT devices are running RPL routing (one of the most common standard routing protocols for IoT applications). We implement a mobility controller at the Fog-server in order to collect measurements made by the Fog nodes and send commands to IoT devices. In this thesis work, we assume that the commands are related to the mobility pattern of mobile node (e.g. AGVs in industrial automation) in order to avoid collision. From the simulation results we can conclude that sampling rates and node density have a greater impact on performance compared to payload size. We cannot be sure that our results reflect what a real-world evaluation would imply as we are running an emulation software, even though it has a very realistic physical layer. We do however believe that with substantial testing and improvements to both Cooja and our implementation, an accurate representation can be accomplished and algorithms in Cooja can be moved to real-world implementations.

The Internet of Things (IoT) is seen as one of the next Internet revolutions. In a near future the majority of all connected devices to the Internet will be IoT devices. These devices will connect previously offline constrained systems, thus it is essential to ensure end-to-end security for such devices. Object Security is a concept where the actual packet or sensitive parts of the packet are encrypted instead of the radio channel. A compromised node in the network will with this mechanism still have the data encrypted ensuring full end-to-end security. This paper proposes an architecture for using the object security format COSE in a typical constrained short-range radio based IoT platform. The IoT platform utilizes Bluetooth Low Energy and the Constrained Application Protocol for data transmission via a capillary gateway. A proof-of-concept implementation based on the architecture validates that the security solution is implementable. An overhead comparison between current channel security guidelines and the proposed object security solution results in a similar size for each data packet. The thesis concludes that object security should be seen as an alternative for ensuring end-to-end security for the Internet of Things.

This Master's thesis „Secure communication and data protection in the internet of things“ is dealing with crypthografy and crypthographic libraries, which are compared with eachother according to supporting algorithm and standard. For comparing therewere used following libraries: openSSL, wolfSSL, nanoSSL and matrixSSL. Practical part of the thesis is focused on testing the productivity of each ciphers and protocols of openSSL and wolfSSL libraries on RaspberryPi 2 device. Further, the thesis shows the design of communication scenario client-server in the Internet of Things (IoT). Simple authentication protocol client-server was implemented and simulated on RaspberryPi 2 device.

With the rapid development of the Internet of Things, Wireless Sensor Networks (WSNs) are deployed increasingly all over the world, providing data that can help increase sustainable development. Currently in Uppsala, Sweden, the GreenIoT project monitors air pollution by using WSNs. The resource constrained nature of WSNs demand that special care is taken in the design of communication models and communication protocols. The publish-subscribe (pub/sub) model suits WSNs very well since it puts an intermediary the broker server between sensor nodes and clients, thus alleviating the workload of the sensor nodes. The IETF (Internet Engineering Task Force) is currently in the process of standardizing a pub/sub extension to the Constrained Application Protocol (CoAP). Since the extension is such a recent addition to CoAP and not yet standardized, there are very few actual implementations of it and little is known of how it would work in practice. The GreenIoT project is considering replacement of their current pub/sub broker with the CoAP pub/sub broker since its underlying implementation is likely to be more energy efficient and the standardizing organization behind CoAP is the well-esteemed IETF. On a general level, this report offers an investigation of the problems and challenges faced when implementing the CoAP pub/sub extension with respect to design choices, implementation and protocol ambiguities. More specifically, a CoAP pub/sub broker is implemented for the GreenIoT project. By means of carefully analyzing the CoAP protocol and CoAP pub/sub draft as well as other necessary protocols, then proceeding to make decisions of what programming language to use as well as what existing CoAP library to use, a broker server was implemented and tested iteratively as the work proceeded. The implementation gave rise to several questions regarding the pub/sub draft which are also discussed in the report. / Den hastiga utvecklingen av Sakernas Internet över hela världen har medfört ett ökat användande av trådlösa sensornätverk vars datainsamling kan bidra till en mer hållbar utveckling. För närvarande använder sig GreenIoT-projektet i Uppsala av trådlösa sensornätverk för att övervaka halterna av luftföroreningar. Resursbegränsningarna för dylika nätverk medför att särskild hänsyn måste tas vid design av såväl kommunikationsmodeller som kommunikationsprotokoll. Modellen Publicera-Prenumerera (pub/pre) passar ypperligt för trådlösa sensornätverk då en mellanhand placeras mellan klient och server en s.k. broker vilket får den positiva effekten att att sensornoderna avlastas. För närvarande är IETF (Internet Engineering Task Force) i färd med att standardisera en pub/pre-utvidgning av det redan standardiserade CoAP (Constrained Application Protocol). Eftersom att utvidgningen är så pass ny finns ytterst få implementationer av den och man vet därmed väldigt lite om hur den faktiskt fungerar i praktiken. GreenIoT-projektet överväger att ersätta sin nuvarande pub/pre-broker med en CoAP pub/pre-broker eftersom att energianvändningen kan antas bli lägre samt att standardiseringsorganisationen bakom CoAP är det välrenommerade IETF. Sett ur ett större perspektiv erbjuder denna rapport en undersökning av de problem och utmaningar man ställs inför vid implementation av CoAP pub/pre-utvidgningen med avseende på designval, implementationsval, och protokolltvetydigheter. Mer konkret implementeras en CoAP pub/pre-broker åt GreenIoT-projektet. Genom att först noggrant analysera CoAP-protokollet, CoAP pub/pre-utkastet, liksom andra nödvändiga protokoll, för att därefter bestämma vilket programmeringsspråk och vilket existerande CoAP-bibliotek som skulle användas, implementerades en broker server som testades iterativt under processens gång. Ett flertal frågor som uppstod rörande pub/pre-utkastet presenteras och diskuteras i rapporten.

Internet of Things, or the infrastructure of the information age society, is an expanding area of research. It is the idea that physical things that we have today, can be turned into devices by being connected to a network. The purpose of these devices is through more sensors and actuators, allow smarter and more robust infrastructure to be built, as well as improving consumer devices interoperability. This thesis will investigate the current state of the art application layer communication protocols that have been developed with resource constrained mobile devices in mind. It will look specifically at high latency mid-range wireless cellular communication by investigating how the protocols affect energy consumption for an embedded Internet of Things device. This is done with the constraint that these findings needs to be applicable to the fifth generation of cellular networks, as well as extensions to current generation standards. The application layer communication protocols Constrained Applications Protocol(CoAP), Message Queue Telemetry Transport(MQTT) and Hypertext Transfer Protocol(HTTP) used on multiple modem modules, are investigated in a quantitative approach in deductive survey experiments, testing a variety of what is concluded to be typical sensor and actuator scenarios. The goal with the survey, is to ultimately select the protocol that shows to be the most suitable for a project to build a prototype platform for embedded mobile devices in the shape of publicly shared bikes in a city. This prototype is described and its architecture and design decisions are presented and argued for. The survey discovers that CoAP is the most suitable protocol for the purpose of the thesis, and proceeds to show how it is applied to the described platform.

Abstract Wireless sensors play a bigger and bigger role in our everyday life and they have become a part of our life in homes, vehicles, traffic, food production and healthcare, monitoring and controlling our activities. Low-cost and resource-efficient solutions are an essential part of this development. The aim of the study was to develop solutions, which improve the energy efficiency of wireless sensor networks yet still fulfil the requirements of monitoring applications. In the study, five new solutions were developed to save energy in wireless sensor networks and all the solutions were studied and verified with test bed implementations. The developed solutions are: 1. Energy-efficient medium access control (MAC), namely revive MAC (R-MAC) for duty-cycling networks with a long sampling interval (many minutes) 2. Wake-up radio solution for on-demand sampling networks, which uses the main radio as the wake-up transmitter 3. Energy-efficient internet of things (IoT) routing solution for wake-up routing with a routing protocol for low-Power and lossy networks (RPL) 4. Energy-efficient IoT compression solution: robust header compression (ROHC) compression with constrained application protocol (CoAP) 5. Data analysis solution based on an energy-efficient sensor node, where filter clogging is forecast from analysis of the vibration data at the node. All the developed solutions were promising and can be utilized in many domain areas. The solutions can be considered as proofs of concept, which need to be developed further for use in final products. / Tiivistelmä Langattomat sensoreilla on yhä suurempi osuus jokapäiväisessä arjessa, jossa langattomat sensorit ovat tulleet osaksi kodin, autojen, ruuantuotannon sekä terveyden valvonta- ja seurantajärjestelmiä. Oleellisena osana tätä kehitystä ovat sekä edulliset että energia- ja resurssitehokkaat ratkaisut. Työn päämääränä oli kehittää ratkaisuja, jotka parantavat langattoman sensoriverkon energia tehokkuutta niin, että edelleen täytetään monitorointi sovellutusten asettamat vaatimukset. Työssä kehitettiin viisi uutta ratkaisua säästää energiaa langattomissa sensoriverkoissa ja kaikki ratkaisut tutkittiin ja varmennetiin työssä tehdyillä testi alustoilla. Kehitetyt ratkaisut ovat: 1. Energiatehokas alempi siirtoyhteyskerroksen protokolla (medium access control, MAC), nimittäin heräävä MAC (Revive MAC, R-MAC) jaksoittain toimiville (duty-cycling) verkoille, joissa on pitkät mittausvälit (useita minuutteja). 2. Heräteradioratkaisu (wake-up) pyynnöstä toimiville (on-demand) verkoille, joissa pääradiota käytetään heräte signaalin lähettämiseen. 3. Energiatehokas esineiden internetin (Internet of Things, IoT) reititysratkaisu herätereititykseen käyttäen matalatehoisille ja häviöllisille verkoille suunniteltua reititysprotokollaa (Routing protocol for low-Power and Lossy networks, RPL). 4. Energiatehokas IoT-pakkausratkaisu: varmatoiminen otsakkeen pakkausprotokolla (Robust Header Compression, ROHC) yhdessä rajoitettujen sovellusten protokollan (Constrained Application Protocol, CoAP) kanssa. 5. Energiatehokas sensorilaite perusteinen data prosessointi ratkaisu suodattimen tukkeutumisen ennustamiseen värähtelymittauksia käyttäen. Kaikki kehitetyt ratkaisut olivat lupaavia ja niitä voidaan käyttää useilla sovellutusalueilla. Ratkaisut ovat soveltuvuusselvityksiä (proof of concept), joita pitää kehittää edelleen loppu tuotteiden käyttöön.