O modelo de atores tem sido visto como uma abordagem alternativa à programação concorrente convencional, baseada em travas e variáveis de condição. Atores são agentes computacionais que se comunicam por troca de mensagens e que possuem uma caixa de correio e um comportamento. As mensagens destinadas a um ator são armazenadas na caixa de correio do ator e processadas de maneira assíncrona. Sistemas de middleware orientados a mensagens trabalham com troca assíncrona de mensagens e formam uma base que simplifica o desenvolvimento de aplicações distribuídas. Tais sistemas permitem interoperabilidade com baixo acoplamento e provêm suporte para tratamento robusto de erros em caso de falhas. Message brokers são frequentemente apresentados como uma tecnologia que pode mudar a maneira com que sistemas distribuídos são construídos. A especificação AMQP é uma proposta recente de padronização de um protocolo para message brokers. Neste trabalho exploramos a potencial sinergia entre um message broker e uma implementação do modelo de atores. Criamos uma versão modificada da implementação do modelo de atores do projeto Akka que utiliza um message broker AMQP como mecanismo de transporte de mensagens para atores remotos. / The actor model has been seen as an alternative for conventional concurrent programming based on locks and condition variables. Actors are computational agents that communicate by sending messages and have a mailbox and a behavior. The messages sent to an actor are stored in its mailbox and are asynchronously processed. Message oriented middleware systems work with asynchronous message exchange and create a base that simplifies the development of distributed applications. These systems have interoperability with low coupling and provide support for robust error handling in case of failures. Message brokers are often presented as a technology that can change the way distributed systems are built. The AMQP specification is a recent proposal of a standard protocol for message brokers. In this document we explore the potential synergy between a message broker and an implementation of the actor model. We created a modified version of the actor model implementation provided by the Akka project. Our modified implementation uses an AMQP message broker as the transport engine for messages to remote actors.

O modelo de atores tem sido visto como uma abordagem alternativa à programação concorrente convencional, baseada em travas e variáveis de condição. Atores são agentes computacionais que se comunicam por troca de mensagens e que possuem uma caixa de correio e um comportamento. As mensagens destinadas a um ator são armazenadas na caixa de correio do ator e processadas de maneira assíncrona. Sistemas de middleware orientados a mensagens trabalham com troca assíncrona de mensagens e formam uma base que simplifica o desenvolvimento de aplicações distribuídas. Tais sistemas permitem interoperabilidade com baixo acoplamento e provêm suporte para tratamento robusto de erros em caso de falhas. Message brokers são frequentemente apresentados como uma tecnologia que pode mudar a maneira com que sistemas distribuídos são construídos. A especificação AMQP é uma proposta recente de padronização de um protocolo para message brokers. Neste trabalho exploramos a potencial sinergia entre um message broker e uma implementação do modelo de atores. Criamos uma versão modificada da implementação do modelo de atores do projeto Akka que utiliza um message broker AMQP como mecanismo de transporte de mensagens para atores remotos. / The actor model has been seen as an alternative for conventional concurrent programming based on locks and condition variables. Actors are computational agents that communicate by sending messages and have a mailbox and a behavior. The messages sent to an actor are stored in its mailbox and are asynchronously processed. Message oriented middleware systems work with asynchronous message exchange and create a base that simplifies the development of distributed applications. These systems have interoperability with low coupling and provide support for robust error handling in case of failures. Message brokers are often presented as a technology that can change the way distributed systems are built. The AMQP specification is a recent proposal of a standard protocol for message brokers. In this document we explore the potential synergy between a message broker and an implementation of the actor model. We created a modified version of the actor model implementation provided by the Akka project. Our modified implementation uses an AMQP message broker as the transport engine for messages to remote actors.

This thesis project has studied a number of protocols that could be used to communicate between a vehicle and a remote server in the context of Scania’s connected services. While there are many factors that are of interest to Scania (such as response time, transmission speed, and amount of data overhead for each message), this thesis will evaluate each protocol in terms of how much data overhead is introduced and how packet loss affects this overhead. The thesis begins by giving an overview of how a number of alternative protocols work and what they offer with regards to Scania’s needs. Next these protocols are compared based on previous studies and each protocol’s specifications to determine which protocol would be the best choice for realizing Scania’s connected services. Finally, a test framework was set up using a virtual environment to simulate different networking conditions. Each of the candidate protocols were deployed in this environment and setup to send sample data. The behaviour of each protocol during these tests served as the basis for the analysis of all of these protocols. The thesis draws the conclusion that to reduce the data transmission overhead between vehicles and Scania’s servers the most suitable protocol is the UDP based MQTT SN. / I den här rapporten har jag undersökt ett antal protokoll som kan användas för att kommunicera mellan server och lastbil och därmed användas för Scanias Connected Services. Då det är många faktorer som är intressanta när det kommer till kommunikation mellan lastbil och server för Scania som till exempel responstid, överföringshastighet och mängden extra data vid överföring så har jag valt att begränsa mig till att utvärdera protokollen utifrån hur mycket extra data de använder vid överföring och hur detta påverkas av paketförlust. Rapporten börjar med att ge en överblick över vilka tänkbara protokoll som kan användas och vad de kan erbjuda gällande Scanias behov. Efter det så jämförs protokollen baserat på tidigare studier och protokollens specifikationer för att avgöra vilket protokoll som är bäst lämpat att användas i Scanias Connected Services. Sists så skapas ett virtuellt ramverk för att simulera olike nätverksförhållanden. Här testas varje protokoll och får sända olike datamängder för att sedan få sin prestanda utvärderad baserat på hur mycket extra data som sändes. Dessa resultat ligger sedan till grund för den analys och slutsats angående vilket protokoll som är bäst lämpat att användas av Scania. Rapporten drar slutsatsen att baserat på den information som finns tillgänglig och de resultat som ficks av testerna så skulle den UDP baserade MQTT-SN vara bäst lämpad för att minimera mängden extra data som skickas.

Med en ökande tillväxt inom flygtrafikbranschen behöver de bakomliggande flygtrafikledningssystemen uppgraderas för att möta den växande komplexiteten i syfte att säkerställa en ordnad flygtrafik. Här anses det arkitekturella konceptet System Wide Information Management (SWIM) för distribuerade flygledningssystem vara lösningen för att bygga system som är lättare att underhålla och enklare kan kan samverka med varandra. År 2021 fastslog Europeiska unionen att samtliga operativa intressenter inom det aeronautiska informationsutbytet i EU skall tillhandahålla och kunna konsumera SWIM-tjänster och erbjöd då en uppsättning tjänstegränssnittsbindningar för intressenter att hävda foglighet med för att efterfölja de nya regleringarna. Bland dessa finner vi AMQP Messaging och WS Light som utiliserar AMQP respektive HTTP som meddelandeprotokoll. Tidigare forskning har visat att AMQP presterar bättre än HTTP inom de flesta områden, men denna studie undersöker om någon av de två lämpar sig bättre som meddelandeprotokoll för en europabaserad SWIM-implementation genom att analysera resultatet i en SWIM-kontext. Med hjälp av en komparativ analys och kvantitativ dataanalys jämförs de två meddelandeprotokollen i denna studie för att identifiera liknande och åtskiljande karaktärsdrag samt för att svara på om någon av de två lämpar sig bättre för ändamålet. De punkter protokollen jämförs på är struktur, overhead och effektivitet, interoperabilitet och kompabilitet, tillförlitlighet och feltolerans samt förekomster i Eurocontrols SWIM Registry. Studiens resultat visar att AMQP är den lämpligaste kandidaten av de två sett till implementationstrender och prestanda, men att det är bör göras en avvägning innan en intressent väljer vilket gränssnitt denne skall implementera. / With an increasing growth within the aviation industry, the underlying air traffic control systems needs to be upgraded to meet the growing complexity for ensuring an organized air traffic. This is where the architectural concept System Wide Information Management (SWIM) for distributed air traffic control systems is believed to be the solution for building systems that are easier to maintain and can cooperate with ease. In the year 2021, the European Union decided that all operative stakeholders within the aeronautical information exchange in EU shall provide and be able to consume SWIM services, and provided a set of service interface bindings for stakeholders to claim conformance to in order to follow the new regulations. Among these we find AMQP Messaging and WS Light that utilizes AMQP and HTTP, respectively, as messaging protocols. Previous research has shown that AMQP performs better than HTTP in most areas, but this study analyses the result in a SWIM context to see if any of the two is a more suitable messaging protocol in a Europe based SWIM implementation. Through a comparative analysis and a quantitative data analysis the two messaging protocols are compared in this study to identify similar and distinctive characteristics to answer whether one of the two is a better candidate for the purpose. The protocols are compared on their structure, overhead and efficiency, interoperability and fault tolerance, and their occurances in Eurocontrol's SWIM Registry. The result of the study shows that AMQP is the more suitable candidate of the two, in regards to trends in current implementations as well as performance metrics, but a stakeholder should make a trade-off before choosing what service interface binding to implement.

Many industries are now moving several of their processes into the cloud computing sphere. One important process is to collect machine data in an effective way. Moving signal collection processes to the cloud instead of on premise raises many questions about performance, scalability, security and cost.This thesis focuses on some of the market leading and cutting edge protocols appropriate for industrial production data collection. It investigates and compares the pros and cons of the protocols with respect to the demands of industrial systems. The thesis also presents examples of how the protocols can be used to collect data all the way to a higher-level system such as ERP or MES.The protocols focused on are MQTT and AMQP (in OPC-UA). The possibilities of OPC-UA in cloud computing is of extra interest to investigate in this thesis due to its increasing usage and development.

A current challenge in the Internet of Things is the seeking after conceptual structures to connect the presumably billions of devices of innumerable forms and capabilities. An emerging architectural concept, the fog cloud computing, moves the seemingly unlimited computational power of the distant cloud to the edge of the network, closer to the potentially computationally limited things, effectively diminishing the experienced latency. To allow computationally-constrained devices partaking in the network they have to be relieved from the burden of constant availability and extensive computational execution. Establishing a publish/subscribe communication pattern with the utilization of the popular Internet of Things application layer protocol Constrained Application Protocol is depicted one approach of overcoming this issue. In this project, a Java based library to establish a publish/subscribe communication pattern for the Constrained Application Protocol was develop. Furthermore, efforts to build and assess prototypes of several publish/subscribe application layer protocols executed over varying common as well as secured versions of the standard and non-standard transport layer protocols were made to take advantage, evaluate, and compare the developed library. The results indicate that the standard protocol stacks represent solid candidates yet one non-standard protocol stack is the considered prime candidate which still maintains a low response time while not adding a significant amount of communication overhead.

The Internet of Things market grows at an extreme rate each passing year. Devices will gather more data, which puts a lot of pressure on the communication between the devices and the cloud. The protocols used needs to be fast, secure, reliable and send any type of content. This thesis work conducts a research of the three most popular application level protocols ; MQTT, HTTP and AMQP, to examine which is best suited in an Internet of Things environment. The project is made with Axians AB to provide insight regarding the protocols, so that the company can decide which protocol will be best suited for their projects. A theoretical study of the performance was made, followed by case studies on different aspects of the protocol. The case studies were made using a Dell gateway and a 4G connection to mimic a real world project. Scripts were developed to measure different performance attributes of the protocols. The analysis and discussion of the results proved that MQTT or AMQP is the best protocols, depending on the project.

Att flera datorer används för att gemensamt lösa problem är inte någonting nytt. Det finns många distribuerade system i bruk och många olika lösningar för hur dessa ska kommunicera med varandra. Vissa använder sig av meddelande-orienterade lager för kommunikation vilket det finns väldigt många implementationer av. RabbitMQ är ett exempel där att kommunikation går genom en (eller ett kluster av) central nod och kommunicerar med hjälp av protokollet Advanced Message Queue Protocol, AMQP. I en helt annan kategori finns ZeroMQ som inte definierar någon central nod för all kommunikation att passera utan peer to peer är istället möjlig vilket innebär snabbare responstider men försvårar hur olika klienter hittar till varandra. Det bloggindexerande företaget Twingly kör idag med ett distribuerat system som använder flera olika kösystem för att koordinera ut arbete till de olika datorerna. De vill kolla närmare på hur de kan bygga sitt system med hjälp av meddelande-orienterade lager. Resultatet av arbetet är att RabbitMQ innebär mindre komponenter att hålla reda på vilket innebär att koden blir mindre komplex. Det som kommer gratis med att använda RabbitMQ är just att klienterna inte behöver känna till varandra utan endast behöver känna till RabbitMQ-servern. Nackdelen är att RabbitMQ-servern kommer bli en flaskhals för systemet. ZeroMQ är däremot friare att implementera den funktionalitet man själv behöver vilket är till fördel i de fall tid och pengar finns för att skapa ett eget system byggt ovanpå ZeroMQ. För Twingly som vill ha ett system inom en snar framtid är RabbitMQ ett bättre val av dessa två alternativ.

Genetic algorithms are modern algorithms intended to solve optimization problems. Inspiration originates in evolutionary principles in nature. Parallelization of genetic algorithms provides not only faster processing but also new and better solutions. Parallel genetic algorithms are also closer to real nature than their sequential counterparts. This paper describes the most used models of parallelization of genetic algorithms. Moreover, it provides the design and implementation in programming language Python. Finally, the implementation is verified in several test cases.

Výkonností testování aplikací nabírá v poslední době na důležitosti během vývoje všeho druhu. Tato práce mapuje základy testování výkonu, které jsou aplikovatelné na libovolné aplikace a následně analýzuje testování výkonu komponent používaných v Messaging systémech a to konkrétně Apache ActiveMQ Artemis a Qpid-Dispatch. Využívané metody testování výkonu je zaměřeno zejména na Apache ActiveMQ Artemis pomocí systému Messaging Performance Tool s názvem Maestro. Práce navrhuje vylepšení této aplikace o rozšíření testování systému Qpid-Dispatch a její možnosti při automatizovaném testování. Řešení je demonstrováno na sérii experimentů s různými topologiemi. Výsledná zpráva závěrem vyhodnocuje navržené rozšíření systému Maestro, zhodnocuje výkon komponenty Qpid-Dispatch a rozvíjí myšlenky pro další rozšíření.