Orientador: Frank José Affonso / Resumo: O cenário atual de desenvolvimento de software tem revelado um uso crescente de aplicações baseadas em serviços. Em um ambiente de computação distribuída, monitorar a qualidade de serviços para que essa aplicação não apresente algum tipo de anomalia ou interrupção pode ser considerada uma tarefa vital. Para isso, é necessário prover meios para o desenvolvimento de sistemas baseados em serviços capazes de observar seu estado interno de execução e/ou contexto ao qual estão inseridos e reagir diante de mudanças ou algum tipo de imprevisibilidade. Aplicações orientadas a serviços que permitem adaptação em tempo de execução podem ser classificadas como Self-Apps (do inglês, Self-adaptive Service-oriented Applications). Em função da complexidade intrínseca a esse tipo de aplicação, o uso de frameworks tem se mostrado uma alternativa viável por aliviar a carga cognitiva de desenvolvimento, a qual envolve o conhecimento de diversas áreas de pesquisa. Motivado por esse cenário, durante a realização deste trabalho foi conduzida uma revisão da literatura que engloba a condução de um mapeamento sistemático e consultas complementares em bases nacionais de teses e dissertações. Essa revisão permitiu obter um panorama detalhado referente ao estágio atual da pesquisa, seus desafios e as perspectivas futuras sobre frameworks para Self-Apps. Embasado nos resultados dessa revisão, o objetivo deste trabalho é o desenvolvimento do framework DynaMS (do inglês, Dynamic Deployment, QoS Metrics and S... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The current software development scenario has shown a crescent usage of service-based applications. In a distributed computing environment, the monitoring of the service’s quality is a relevant task because aims to assure that it does not present any anomaly or interruption. To do so, it is necessary to provide means to develop service-based systems that are capable to observe their internal execution state and/or the context in which they are inserted and to react in face of changes or unforeseen circumstances. Service-oriented applications that are able to perform adaptation in runtime can be classified as Self-Apps (i.e., Self-adaptive Service-oriented Applications). Given the complexity involved in this type of application, the use of frameworks has been shown as a viable alternative to reduce the cognitive development load regarding the knowledge from different research areas. Motivated by this scenario, we conducted a literature review as a part of this work. This review includes a systematic mapping and complementary searches to national thesis and dissertations’ databases. This review provided us a detailed panorama about the current stage of research, its challenges and the future perspectives regarding frameworks for Self-Apps. Based on the results from this review, the purpose of this Master’s project is to present a framework called DynaMS (Dynamic Deployment, QoS Metrics and Semantic Search) to support the development of this type of application. In short, this f... (Complete abstract click electronic access below) / Mestre

Modern technologies are growing and Voice over Internet Protocol (VoIP) technology is able to function in heterogeneous networks. VoIP gained wide popularity because it offers cheap calling rates compared to traditional telephone system and the number of VoIP subscribers has increased significantly in recent years. End users need reliable and acceptable call quality in real time communication with best Quality of Service (QoS). Server complexity is increasing to handle all client requests simultaneously and needs huge processing power. VoIP Servers will increase processing power but the engineering tradeoff needs to be considered e.g. increasing hardware will increase hardware complexity, energy consumption, network management, space requirement and overall system complexity. Modern System-on-Chip (SoC) uses multiple core technology to resolve the complexity of hardware computation. With enterprises needing to reduce overall costs while simultaneously improving call setup time, the amalgamation of VoIP with SoC can play a major role in the business market. The proposed VoIP Server model with multiple processing capabilities embedded in it is tailored for multicore hardware to achieve the required result. The model uses SystemC-2.2.0 and TLM-2.0 as a platform and consists of three main modules. TLM is built on top of SystemC in an overlay architectural fashion. SystemC provides a bridge between software and hardware co-design and increases HW & SW productivity, driven by fast concurrent programming in real time. The proposed multicore VoIP Server model implements a round robin algorithm to distribute transactions between cores and clients via Load Balancer. Primary focus of the multicore model is the processing of call setup time delays on a VoIP Server. Experiments were performed using OpenSIP Server to measure Session Initiation Protocol (SIP) messages and call setup time processing delays. Simulations were performed at the KTH Ferlin system and based on the theoretical measurements from the OpenSIP Server experiments. Results of the proposed multicore VoIP Server model shows improvement in the processing of call setup time delays.

The Data Distribution Service (DDS) is a flexible, decentralized, peer-to-peer communication middle-ware. This thesis presents a performance analysis of the DDS usage in the Toyota Smartness platform that is used in Toyota’s Autonomous Guided Vehicles (AGVs). The purpose is to find if DDS is suitable for internal communication between modules that reside within the Smartness platform and for external communication between AGVs that are connected in the same network. An introduction to the main concepts of DDS and the Toyota Smartness platform architecture is given together with a presentation of some earlier research that has been done in DDS. A number of different approaches of how DDS can be integrated to the Smartness platform are explored and a set of different configurations that DDS provides are evaluated. The tests that were performed in order to evaluate the usage of DDS are described in detail and the results that were collected are presented, compared and discussed. The advantages and disadvantages of using DDS are listed, and some ideas for future work are proposed.

Traditionally the Internet is used for the following applications: FTP, e-mail and Web traffic. However in the recent years the Internet is increasingly supporting emerging applications such as IP telephony, video conferencing and online games. These new applications have different requirements in terms of throughput and delay than traditional applications. For example, interactive multimedia applications, unlike traditional applications, have more strict delay constraints and less strict loss constraints. Unfortunately, the current Internet offers only a best-effort service to all applications without any consideration to the applications specific requirements. In this thesis three existing Active Queue Management (AQM) mechanisms are modified by incorporating into these a control function to condition routers for better Quality of Service (QoS). Specifically, delay is considered as the key QoS metric as it is the most important metric for real-time multimedia applications. The first modified mechanism is Drop Tail (DT), which is a simple mechanism in comparison with most AQM schemes. A dynamic threshold has been added to DT in order to maintain packet queueing delay at a specified value. The modified mechanism is referred to as Adaptive Drop Tail (ADT). The second mechanism considered is Early Random Drop (ERD) and, iii in a similar way to ADT, a dynamic threshold has been used to keep the delay at a required value, the main difference being that packets are now dropped probabilistically before the queue reaches full capacity. This mechanism is referred to as Adaptive Early Random Drop (AERD). The final mechanism considered is motivated by the well known Random Early Detection AQM mechanism and is effectively a multi-threshold version of AERD in which packets are dropped with a linear function between the two thresholds and the second threshold is moveable in order to change the slope of the dropping function. This mechanism is called Multi Threshold Adaptive Early Random Drop (MTAERD) and is used in a similar way to the other mechanisms to maintain delay around a specified level. The main focus with all the mechanisms is on queueing delay, which is a significant component of end-to-end delay, and also on reducing the jitter (delay variation) A control algorithm is developed using an analytical model that specifies the delay as a function of the queue threshold position and this function has been used in a simulation to adjust the threshold to an effective value to maintain the delay around a specified value as the packet arrival rate changes over time. iv A two state Markov Modulated Poisson Process is used as the arrival process to each of the three systems to introduce burstiness and correlation of the packet inter-arrival times and to present sudden changes in the arrival process as might be encountered when TCP is used as the transport protocol and step changes the size of its congestion window. In the investigations it is assumed the traffic source is a mixture of TCP and UDP traffic and that the mechanisms conserved apply to the TCP based data. It is also assumed that this consists of the majority proportion of the total traffic so that the control mechanisms have a significant effect on controlling the overall delay. The three mechanisms are evaluated using a Java framework and results are presented showing the amount of improvement in QoS that can be achieved by the mechanisms over their non-adaptive counterparts. The mechanisms are also compared with each other and conclusions drawn.

As the number of people using wireless networks is increasing, the need to reduce the vulnerability of wireless networks from node or link failures that cause loss of data is becoming a priority. Also the present techniques and topologies used for wireless networking are not sufficient to handle the traffic load even if we solve the issues of reliability and resilience. Packet loss or delay is increasingly likely due to the increase in the number of packets as technology is evolving and more video and voice packets along with the data packets are being transmitted. Only the efficient and intelligent use of the shared medium can solve the problem and help in avoiding the collision or delay among the packets using a newly proposed intelligent topology. Wireless technology offers the potential to replace wires from many applications, particularly for the rapid deployment of networks for permanent or temporary use. Fiber_ optic metropolitan area networks (WAN) provide security and resilience. A target of the research was to match this in the wireless environment. This research investigates the suitability if using wireless technology for the establishment of a MAN by adding features to enhance resilience. We proposed a mechanism that may be rapidly deployed and provide automatic configuration. Research work and simulation design has been used to develop a new wireless network topology for an efficient and intelligent packet transmission by identifying reliable routes. This novel idea will help give wireless as well as mobile technology a clear edge over wired technology, not only in the case of mobility but also in the case of security of data and other services. A decision based routing tree mechanism has been developed, that can establish routes in an ad-hoc network which may than be configured into a logical dual ring. At the same time the proposed system proposes to embed the quality of service mechanisms, resilience, and reliability features from RPR. The simulations were created using Microsoft Visual Studio.Net for the Decision based routing algorithm. The results were compared with an existing LAR algorithm. We have obtained 95% confidence intervals on all the performance analysis results to indicate accuracy.

The Information and Communication Technology (ICT) industry is one of the most energy consuming industries in the world. With the increase of the number of global mobile traffic users which is growing rapidly for each year, it is more important than ever for all industries to implement energy efficient methods to decrease the greenhouse gas emissions. This thesis looks into Ericsson, one of the largest companies within ICT, and how their energy efficient methods in LTE impact the end-users. The experiment was conducted in an Ericsson laboratory in Lund and the results showed that some quality of service metrics (latency,throughput, etc.) were impacted by the different energy efficient features enabled. However, performing a mean opinion score showed that the end-users were not as affected while browsing through different sites and streaming videos in 720p. While the experiment was performed on a smaller scale (4 User Equipments and 3 end-users) the result was promising enough for it to be conducted on a larger scale in the future. With enough data Ericsson and other ICT companies can be able to convince mobile operators to enable more energy efficient features (without it having any impact on the end-users) while fighting the climate change.

Currently, there is a lack of research behind the security of Virtual Reality against fingerprinting attacks and how these affect the Quality of Experience (QoE) and Quality of Service (QoS) for a user. With practical testing in a game which implements traffic shaping methods as security defences, this thesis aims to take the first step towards changing this. Here, tests were made testing QoS and QoE of countermeasures in a VR game using the game-engine Unity. The countermeasures utilized were random padding, random delays and VPNs. The conclusion reached was that using a delay had a significant impact on QoE, creating a high Round-Trip Time, while changing the packet size had minimal impact to both QoE and QoS. Additionally, utilizing a VPN yielded a minimal impact to both the QoE and QoS.

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