Design, implementation and evaluation of a QoS-aware transport protocol

In the context of a reconfigurable transport protocol framework, we propose a QoS-aware Transport Protocol (QSTP), specifically designed to operate over QoS-enabled networks with bandwidth guarantee. QSTP combines QoS-aware TFRC congestion control mechanism, which takes into account the network-level bandwidth reservations, with a Selective ACKnowledgment (SACK) mechanism in order to provide a QoS-aware transport service that fill the gap between QoS enabled network services and QoS constraint applications. We have developed a prototype of this protocol in the user-space and conducted a large range of measurements to evaluate this proposal under various network conditions. Our results show that QSTP allows applications to reach their negotiated QoS over bandwidth guaranteed networks, such as DiffServ/AF network, where TCP fails. This protocol appears to be the first reliable protocol especially designed for QoS network architectures with bandwidth guarantee

Energy-Efficient NOMA Enabled Heterogeneous Cloud Radio Access Networks

Heterogeneous cloud radio access networks (H-CRANs) are envisioned to be promising in the fifth generation (5G) wireless networks. H-CRANs enable users to enjoy diverse services with high energy efficiency, high spectral efficiency, and low-cost operation, which are achieved by using cloud computing and virtualization techniques. However, H-CRANs face many technical challenges due to massive user connectivity, increasingly severe spectrum scarcity and energy-constrained devices. These challenges may significantly decrease the quality of service of users if not properly tackled. Non-orthogonal multiple access (NOMA) schemes exploit non-orthogonal resources to provide services for multiple users and are receiving increasing attention for their potential of improving spectral and energy efficiency in 5G networks. In this article a framework for energy-efficient NOMA H-CRANs is presented. The enabling technologies for NOMA H-CRANs are surveyed. Challenges to implement these technologies and open issues are discussed. This article also presents the performance evaluation on energy efficiency of H-CRANs with NOMA.Comment: This work has been accepted by IEEE Network. Pages 18, Figure

Microservice Transition and its Granularity Problem: A Systematic Mapping Study

Microservices have gained wide recognition and acceptance in software industries as an emerging architectural style for autonomic, scalable, and more reliable computing. The transition to microservices has been highly motivated by the need for better alignment of technical design decisions with improving value potentials of architectures. Despite microservices' popularity, research still lacks disciplined understanding of transition and consensus on the principles and activities underlying "micro-ing" architectures. In this paper, we report on a systematic mapping study that consolidates various views, approaches and activities that commonly assist in the transition to microservices. The study aims to provide a better understanding of the transition; it also contributes a working definition of the transition and technical activities underlying it. We term the transition and technical activities leading to microservice architectures as microservitization. We then shed light on a fundamental problem of microservitization: microservice granularity and reasoning about its adaptation as first-class entities. This study reviews state-of-the-art and -practice related to reasoning about microservice granularity; it reviews modelling approaches, aspects considered, guidelines and processes used to reason about microservice granularity. This study identifies opportunities for future research and development related to reasoning about microservice granularity.Comment: 36 pages including references, 6 figures, and 3 table

Seamless connectivity:investigating implementation challenges of multibroker MQTT platform for smart environmental monitoring

Abstract. This thesis explores the performance and efficiency of MQTT-based infrastructure Internet of Things (IoT) sensor networks for smart environment. The study focuses on the impact of network latency and broker switching in distributed multi-broker MQTT platforms. The research involves three case studies: a cloud-based multi-broker deployment, a Local Area Network (LAN)-based multi-broker deployment, and a multi-layer LAN network-based multi-broker deployment. The research is guided by three objectives: quantifying and analyzing the latency of multi-broker MQTT platforms; investigating the benefits of distributed brokers for edge users; and assessing the impact of switching latency at applications. This thesis ultimately seeks to answer three key questions related to network and switching latency, the merits of distributed brokers, and the influence of switching latency on the reliability of end-user applications

Micro ad-hoc Health Social Networks (uHSN). Design and evaluation of a social-based solution for patient support

Objective: To contribute the design, development, and assessment of a new concept: Micro ad hoc Health Social Networks (uHSN), to create a social-based solution for supporting patients with chronic disease. Design: After in-depth fieldwork and intensive co-design over a 4-year project following Community-Based Participatory Research (CBPR), this paper contributes a new paradigm of uHSN, defining two interaction areas (the “backstage” the sphere invisible to the final user, where processes that build services take place; and the “onstage” the visible part that includes the patients and relatives), and describes a new transversal concept, i.e., “network spaces segments, ” to provide timely interaction among all involved profiles and guaranteeing qualitative relationships. This proposal is applicable to any service design project and to all types of work areas; in the present work, it served as a social-based solution for supporting patients with chronic disease in two real-life health scenarios: a Parkinson disease patient association and a Stroke rehabilitation service in a hospital. These two scenarios included the following main features: thematic (related to the specific disease), private, and secure (only for the patient, relatives, healthcare professional, therapist, carer), with defined specific objectives (around patient support), small size (from tens to hundreds of users), ability to integrate innovative services (e.g., connection to hospital information service or to health sensors), supported by local therapeutic associations, and clustered with preconfigured relationships among users based in network groups. Measurements: Using a mixed qualitative and quantitative approach for 6 months, the performance of the uHSN was assessed in the two environments: a hospital rehabilitation unit working with Stroke patients, and a Parkinson disease association providing physiotherapy, occupational therapy, psychological support, speech therapy, and social services. We describe the proposed methods for evaluating the uHSN quantitatively and qualitatively, and how the scientific community can replicate and/or integrate this contribution in its research. Results: The uHSN overcomes the main limitations of traditional HSNs in the main areas recommended in the literature: privacy, security, transparency, system ecology, Quality of Service (QoS), and technology enhancement. The qualitative and quantitative research demonstrated its viability and replicability in four key points: user acceptance, productivity improvement, QoS enhancement, and fostering of social relations. It also meets the expectation of connecting health and social worlds, supporting distance rehabilitation, improving professionals’ efficiency, expanding users’ social capital, improving information quality and immediacy, and enhancing perceived peer/social/emotional support. The scientific contributions of the present paper are the first step not only in customizing health solutions that empower patients, their families, and healthcare professionals, but also in transferring this new paradigm to other scientific, professional, and social environments to create new opportunities