Open Platform Communication Unified Architecture, or OPC UA, is a world-leading communication protocol specializing in unifying and automating production systems communication. In 2018 the OPC Foundation, an industrial consortium, started the OPC UA Field eXchange initiative to develop the current protocol to extend the reach of the communication down to field level devices like sensors and actuators. This paper explores whether OPC UA FX software can be implemented and integrated with HMS Networks’ product AnyBus CompactCom M40.  The problem formulation stems from the future need for factory communication. For factories to compete, they need to adapt and keep up with the technological progression. OPC UA FX is based on decentralized communication where devices transmit data to each other by distributing the load over the entire system.   The purpose of this report is to, based on the Open62541 implementation, develop software that extends OPC UA with PubSub functionality and methods that enable two or more instances to run as an FX application, meaning that the program publishes and subscribes data simultaneously. Once the software is developed, we integrate it on an AnyBus CompactCom 40 module. This will work as a communication prototype that proves that it is possible to extend OPC UA with FX into HMS Networks’ products.  Open62541 is used to gather libraries and methods needed for OPC UA development. The software is developed using C in Visual Studios and integrated into the hardware using Eclipse.  The result in the form of software was a connection-oriented data exchange, based on the OPC UA information model, where two or more instances can publish and subscribe to information simultaneously. HMS Networks can use the result on their way to implementing OPC UA FX in their products.  In conclusion, the Open62541 implementation is beneficial when developing the OPC UA protocol. The software is complete, but it could not be fully integrated into the CompactCom module. The achieved application is still useful for the development of HMS Network’s products that might use the protocol. / Open Platform Communication Unified Architechure, eller OPC UA, är ett av de världsledande kommunikationsprotokoll som är specialiserat i att förena kommunikation i produktionssystem. 2018 startade OPC Foundation, ett industriellt konsortium, ett initiativ vid namn OPC UA Field eXchange med målet att utvekcla det nuvarande protokollet så att det kan användas till kommunikation på låg nivå, exempelvis mellan sensorer och ställdon. Denna rapport utforskar ifall det är möjligt att utveckla protokollet och integrera det i HMS Networks modul AnyBus CompactCom 40.  Problemformluleringen baseras på framtida behov hos fabriker relaterat till automatisering. För att konkurrera framöver behöver fabriker anpassa sig till utvecklingen inom automatisering. OPC UA FX fokuserar på decentralierad kommunikation mellan enheter som fältanordning, maskin och moln samtidigt för att belastningen ska delas upp över hela systemet. Samtidigt som enheter i industiella nätverket fritt ska kunna överföra data mellan varandra oberoende vilken tillverkare som skapat enheten.   Syftet med arbetet är att, baserat på Open62541, utveckla PubSub teknologi med metoder som möjlighetsgör att två eller fler instanser av en FX applikation ska kunna transportera data genom att prenumerera på och publicera data samtidigt. När mjukvaran fungerar är tanken att integrera mjukvaran på en AnyBus CompactCom 40 modul för att bevisa att implementationen är möjlig i ett praktiskt sammanhang.  Open62541 används för att inkludera nödvändiga OPC UA bibliotek, funktionalitet och datatyper. Protokollet utvecklas i C i en VisualStudio miljö och integreras med hjälp av Eclipse. Resultatet i form av mjukvara var en kopplings intriktat data utbyte, baserad på OPC UA information modell, där en eller två instanser av ett program kan publicera och prenumerera på data samtidigt. HMS Networks kan använda resultatet i arbetet att implementera OPC UA FX i deras produkter. ​Sammanfattningsvis är Open62541 ett mycket användbart verktyg för utvekcling av OPC UA protokol. Dessvärre lyckades inte integrationen av mjukvaran i CompactCom modulen helt och hållet, men det som åstadkommits i arbetet kan i hög grad användas för fortsatt utveckling av OPC UA FX i HMS Networks produkter.

Afin de réduire l’intervalle de temps nécessaire entre la publication de l’information sur le Web et sa consultation par les utilisateurs, les sites Web reposent sur le principe de la Syndication Web. Les fournisseurs d’information diffusent les nouvelles informations à travers des flux RSS auxquels les utilisateurs intéressés peuvent s’abonner. L’objectif de la thèse est de proposer un système de notification passant à l’échelle du Web, prenant en considération le grand nombre d’utilisateurs et le débit élevé d’items. Nous proposons un index basé sur les mots-clés des requêtes utilisateurs permettant de retrouver ceux-ci dans les items des flux. Trois structures d’indexation de souscriptions sont présentées. Un modèle analytique pour estimer le temps de traitement et l’espace mémoire de chaque structure est détaillé. Nous menons une étude expérimentale approfondie de l’impact de plusieurs paramètres sur ces structures. Pour les souscriptions jamais notifiées, nous adaptons les index étudiés pour prendre en considération leur satisfaction partielle. Afin de réduire le nombre d’items reçus par l’utilisateur, nous intégrons une deuxième phase de filtrage par nouveauté et diversité considérant l’ensemble d’items déjà reçus par l’utilisateur. / Based on a Publish/Subscribe paradigm, Web Syndication formats such as RSS have emerged as a popular means for timely delivery of frequently updated Web content. According to these formats, information publishers provide brief summaries of the content they deliver on the Web, while information consumers subscribe to a number of RSS feeds and get informed about newly published items. The goal of this thesis is to propose a notification system which scales on the Web. To deal with this issue, we should take into account the large number of users on the Web and the high publication rate of items. We propose a keyword-based index for user subscriptions to match it on the fly with incoming items. We study three indexing techniques for user subscriptions. We present analytical models to estimate memory requirements and matching time. We also conduct a thorough experimental evaluation to exhibit the impact of critical workload parameters on these structures. For subscriptions which are never notified, we adapt the indexes to support a partial matching between subscriptions and items. We integrate a diversity and novelty filtering step in our system in order to decrease the number of notified items for short subscriptions. This filtering is based on the set of items already received by the user.

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.

Le parking intelligent, permettant aux conducteurs d'accéder aux informations de stationnement sur leurs appareils mobiles, réduit les difficultés des usagers. Tout d'abord, nous mettons en lumière la manière de recueillir les informations de parking en introduisant une architecture de réseaux de capteurs multi-saut, et les modèles d'intensité applicative en examinant la probabilité d'arrivées et de départs de véhicules. Puis nous étudions la stratégie de déploiement des réseaux de capteurs et définissons un problème multi-objectifs, puis nous le résolvons sur deux cartes de parking réelles. Ensuite, nous définissons un service Publish-Subscribe pour fournir aux conducteurs des informations pertinentes. Nous illustrons le système dans des réseaux véhiculaires et mobiles et soulignons l'importance du contenu et du contexte du message au conducteur. Afin d'évaluer la résilience du système, nous proposons un modèle Publish-Subscribe étendu et nous l'évaluons dans différentes circonstances imprévues. Notre travail est basé sur la prémisse que les capteurs de parking sont déployés à une grande échelle dans la ville. Nous considérons une vue d'ensemble des services urbains du point de vue de la municipalité. Ainsi, nous faisons la lumière sur deux thèmes principaux: la collecte d'informations sur le déploiement de capteurs et un modèle étendu de Publish-Subscribe. Notre travail donne un guide avant de démarrer un projet de parking intelligent ou tout service urbain similaire en temps réel. Il fournit également une plate-forme d'évaluation valable pour tester des jeux de données plus réalistes, comme des traces de véhicules ou de trafic réseau. / Smart parking, allowing drivers to access parking information through their smart-phone, is proposed to ease drivers' pain. We first spotlight the manner to collect parking information by introducing the multi-hop sensor network architecture, and how the network is formed. We then introduce the traffic intensity models by looking at the vehicle's arrival and departure probabilities, following the heavy-tailed distribution. We study the deployment strategy of wireless on-street parking sensor layouts. We define a multiple-objective problem and solve it with two real street parking maps. In turn, we present a Publish-Subscribe service system to provide good parking information to drivers. We illustrate the system with a vehicular network and point out the importance of content and context of a driver’s message. To evaluate the resilience, we propose an extended Publish-Subscribe model, and evaluate it under different unforeseen circumstances. Our work is based on the premise that large-scale parking sensors are deployed in the city. We look at the whole picture of urban service from viewpoint of the municipality. As such, we shed light on two main topics: the information collection on sensor deployment and an extended version of Publish-Subscribe messaging paradigm. Our work gives a guideline from network-related perspectives for city before launching a smart parking or any similar real-time urban service. It also provides a meaningful evaluation platform for testing more realistic datasets, such as real vehicle traces or network traffic.

Distributed event processing systems suffer from poor scalability and inefficient resource usage caused by load distributions typical in real-world applications. The results of these shortcomings are availability issues, poor system performance, and high operating costs. This thesis proposes three remedies to solve these limitations in content-based publish/subscribe, which is a practical realization of an event processing system. First, we present a load balancing algorithm that relocates subscribers to distribute load and avoid overloads. Second, we propose publisher relocation algorithms that reduces both the load imposed onto brokers and delivery delay experienced by subscribers. Third, we present ``green" resource allocation algorithms that allocate as few brokers as possible while maximizing their resource usage efficiency by reconfiguring the publishers, subscribers, and the broker topology. We implemented and evaluated all of our approaches on an open source content-based publish/subscribe system called PADRES and evaluated them on SciNet, PlanetLab, a cluster testbed, and in simulations to prove the effectiveness of our solutions. Our evaluation findings are summarized as follows. One, the proposed load balancing algorithm is effective in distributing and balancing load originating from a single server to all available servers in the network. Two, our publisher relocation algorithm reduces the average input load of the system by up to 68%, average broker message rate by up to 85%, and average delivery delay by up to 68%. Three, our resource allocation algorithm reduces the average broker message rate even further by up to 92% and the number of allocated brokers by up to 91%.

Distributed event processing systems suffer from poor scalability and inefficient resource usage caused by load distributions typical in real-world applications. The results of these shortcomings are availability issues, poor system performance, and high operating costs. This thesis proposes three remedies to solve these limitations in content-based publish/subscribe, which is a practical realization of an event processing system. First, we present a load balancing algorithm that relocates subscribers to distribute load and avoid overloads. Second, we propose publisher relocation algorithms that reduces both the load imposed onto brokers and delivery delay experienced by subscribers. Third, we present ``green" resource allocation algorithms that allocate as few brokers as possible while maximizing their resource usage efficiency by reconfiguring the publishers, subscribers, and the broker topology. We implemented and evaluated all of our approaches on an open source content-based publish/subscribe system called PADRES and evaluated them on SciNet, PlanetLab, a cluster testbed, and in simulations to prove the effectiveness of our solutions. Our evaluation findings are summarized as follows. One, the proposed load balancing algorithm is effective in distributing and balancing load originating from a single server to all available servers in the network. Two, our publisher relocation algorithm reduces the average input load of the system by up to 68%, average broker message rate by up to 85%, and average delivery delay by up to 68%. Three, our resource allocation algorithm reduces the average broker message rate even further by up to 92% and the number of allocated brokers by up to 91%.

This thesis defines a generic framework that allows building high level services, of both data search and content distribution, for structured peer-to-peer networks (SPN). We consider a twofold genericity: (i) Extensible framework for services and applications, with a dynamic deploy over other P2P systems; and (ii) generic and portable framework over most of the SPNs. / Esta tesis construye un marco de trabajo genérico que permite construir servicios de alto nivel, tanto de gestión de datos como de distribución de contenidos, para redes peer-to-peer estructradas (RPE). Consideramos que la genericidad proporcionada es doble: (i) Marco de trabajo extensible para servicios y aplicaciones, con un despliegue dinámico sobre diferentes sistemas peer-to-peer; (ii) Marco de trabajo genérico y portable de la mayoría de RPEs.

[pt] Esta dissertação apresenta uma abordagem para a coordenação de enxames de Veículos Aéreos Não Tripulados (VANT), baseada na comunicação via Internet provida pelas redes de telefonia móvel. Um grande número de atividades pode ser coberto com uma missão conjunta de VANTs voando em formação, como a vigilância e monitoramento de grandes eventos, tarefas de busca e salvamento, controle de pestes agrárias, fiscalização e conservação florestal, inspeção de oleodutos e redes de distribuição elétrica ou mesmo em missões militares de ataque e reconhecimento. A coordenação de enxame de VANTs pode ser fatorada na comunicação entre os membros do enxame e o algoritmo de controle e interrelacionamento entre os membros. A solução proposta consiste no uso de smartphones acoplados a VANTs capazes de prover o nível necessário de comunicação confiável sobre a Internet móvel, e processar o algoritmo proposto para a coordenação dos enxames de VANTs. Experimentos foram feitos através da emulação de VANTs e redes de dados de telefonia que demostraram a eficácia do algoritmo proposto e analisam o impacto da latência de rede e da velocidade dos VANTs sobre a precisão da coordenação de movimento de enxames. / [en] This work presents an approach to coordinate swarms of Unmanned Aerial Vehicles (UAV) based on Internet communication provided by mobile phone networks. Several activities can be done by several UAVs flying in formation, such as surveillance and monitoring of mass events, search and rescue tasks, control of agricultural pests, monitoring and forest conservation, inspection of pipelines and electricity distribution networks or even military attack and recognition missions. Coordination of UAVs swarm can be branch in two sub-problems: communication between members of the swarm and the algorithm that controls members behaviors regarding their movements. The proposed solution assumes the use of a smartphone coupled with each UAV of the swarm, in order to provide the required level of reliable communication on the mobile Internet and run the proposed algorithm for the coordination of swarms of UAVs. Experiments were performed with emulated UAVs and WAN mobile networks. The results have demonstrated the effectiveness of the proposed algorithm, and have shown the influence of the network latency and the UAV speeds on the accuracy of the movement coordination in the swarms.

Τα τελευταία χρόνια οι εφαρμογές συνεχούς μετάδοσης ροών πληροφορίας στο διαδίκτυο έχουν γίνει ιδιαίτερα δημοφιλείς. Με τον συνεχώς αυξανόμενο ρυθμό εισόδου νέων αντικειμένων πληροφορίας, γίνεται ολοένα και πιο επιτακτική η ανάγκη για την ανάπτυξη πληροφορικών συστημάτων που να μπορούν να προσφέρουν στους χρήστες τους μόνο εκείνες τις πληροφορίες που τους ενδιαφέρουν, φιλτράροντας τεράστιους όγκους από άσχετες για τον κάθε χρήστη, πληροφορίες. Ένα μοντέλο διάδοσης πληροφορίας ικανό να ενσωματώσει τέτοιου είδους ιδιότητες, είναι το μοντέλο δημοσιεύσεων/συνδρομών βασισμένο στο περιεχόμενο ( content-based publish/subscribe) Βασική συνεισφορά μας στο χώρο είναι η εφαρμογή του μοντέλου δημοσιεύσεων/συνδρομών βασισμένου στο περιεχόμενο (content-based publish/subscribe) πάνω στα δίκτυα ομοτίμων ώστε να μπορέσουμε να προσφέρουμε στους χρήστες υψηλή εκφραστικότητα κατά την δήλωση των ενδιαφερόντων τους, λειτουργώντας σε ένα πλήρως κατανεμημένο και κλιμακώσιμο περιβάλλον. Ο κορμός των προτεινόμενων λύσεων σε αυτή τη διατριβή είναι: (α) η ανάπτυξη αλγορίθμων για την αποθήκευση των κλειδιών των δημοσιεύσεων σε κατάλληλους κόμβους του δικτύου με βάση τις συνθήκες στο περιεχόμενο που έχουν δηλωθεί και (β) αλγορίθμων δρομολόγησης δημοσιεύσεων στο διαδίκτυο έτσι ώστε να ((συναντούν)) αυτούς τους κόμβους οι οποίοι περιέχουν συνδρομές που ικανοποιούνται από την πληροφορία της δημοσίευσης. Οι προτεινόμενοι αλγόριθμοι υλοποιήθηκαν και εξετάσθηκαν ενδελεχώς με προσομοίωση μελετώντας την απόδοσή τους με βάση μετρικές όπως: η δίκαιη κατανομή του φόρτου στους κόμβους του δικτύου από τη διακίνηση μηνυμάτων κατά την επεξεργασία των συνδρομών/δημοσιεύσεων, ο συνολικός αριθμός μηνυμάτων που διακινούνται, ο συνολικός όγκος επιπλέον πληροφορίας που απαιτούν οι αλγόριθμοι να εισέλθει στο δίκτυο (network bandwidth), και ο χρόνος που απαιτείται για την ανεύρεση των συνδρομών που συζευγνύουν με κάθε δημοσίευση. / In the past few years the continuous data streams applications have become particularly popular. With the continuously increasing rate of entry of new information, it becomes imperative the need for developing appropriate infrastructures that will offer only the information that users are interested for, filtering out large volumes of irrelevant for each user, information. The content-based publish/subscribe model, is capable of handling large volumes of data traffic in a distributed, fully decentralized manner. Our basic contribution in this research area is the coupling of the content-based publish/subscribe model with the structured (DHT-based) peer-to-peer networks, offering high expressiveness to users on stating their interests. The proposed infrastructure operated in a distributed and scalable environment. The proposed solutions in this thesis are related to the development and testing: (a) of a number of algorithms for subscription processing in the network and (b) of a number of algorithms for processing the publication events. The proposed algorithms were developed and thoroughly tested with a detailed simulation-based experimentation. The performance metrics are: the fair distribution of load in the nodes of network from the distribution of messages while processing subscriptions and publication events, the total number of messages that are generated, the total volume of additional information that is required from the algorithms to operate, and the time that is required for matching publication events to subscriptions.

Historically, the United States (US) electric grid has been a stable one-way power delivery infrastructure that supplies centrally-generated electricity to its predictably consuming demand. However, the US electric grid is now undergoing a huge transformation from a simple and static system to a complex and dynamic network, which is starting to interconnect intermittent distributed energy resources (DERs), portable electric vehicles (EVs), and load-altering home automation devices, that create bidirectional power flow or stochastic load behavior. In order for this grid of the future to effectively embrace the high penetration of these disruptive and fast-responding digital technologies without compromising its safety, reliability, and affordability, plug-and-play interoperability within the field area network must be enabled between operational technology (OT), information technology (IT), and telecommunication assets in order to seamlessly and securely integrate into the electric utility's operations and planning systems in a modular, flexible, and scalable fashion. This research proposes a potential approach to simplifying the translation and contextualization of operational data on the electric grid without being routed to the utility datacenter for a control decision. This methodology integrates modern software technology from other industries, along with utility industry-standard semantic models, to overcome information siloes and enable interoperability. By leveraging industrial engineering tools, a framework is also developed to help devise a reference architecture and use-case application process that is applied and validated at a US electric utility.