1,476 research outputs found

    Creating Tailored and Adaptive Network Services with the Open Orchestration C-RAN Framework

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    Next generation wireless communications networks will leverage software-defined radio and networking technologies, combined with cloud and fog computing. A pool of resources can then be dynamically allocated to create personalized network services (NSs). The enabling technologies are abstraction, virtualization and consolidation of resources, automatization of processes, and programmatic provisioning and orchestration. ETSI's network functions virtualization (NFV) management and orchestration (MANO) framework provides the architecture and specifications of the management layers. We introduce OOCRAN, an open-source software framework and testbed that extends existing NFV management solutions by incorporating the radio communications layers. This paper presents OOCRAN and illustrates how it monitors and manages the pool of resources for creating tailored NSs. OOCRAN can automate NS reconfiguration, but also facilitates user control. We demonstrate the dynamic deployment of cellular NSs and discuss the challenges of dynamically creating and managing tailored NSs on shared infrastructure.Comment: IEEE 5G World Forum 201

    Scalable processing of aggregate functions for data streams in resource-constrained environments

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    The fast evolution of data analytics platforms has resulted in an increasing demand for real-time data stream processing. From Internet of Things applications to the monitoring of telemetry generated in large datacenters, a common demand for currently emerging scenarios is the need to process vast amounts of data with low latencies, generally performing the analysis process as close to the data source as possible. Devices and sensors generate streams of data across a diversity of locations and protocols. That data usually reaches a central platform that is used to store and process the streams. Processing can be done in real time, with transformations and enrichment happening on-the-fly, but it can also happen after data is stored and organized in repositories. In the former case, stream processing technologies are required to operate on the data; in the latter batch analytics and queries are of common use. Stream processing platforms are required to be malleable and absorb spikes generated by fluctuations of data generation rates. Data is usually produced as time series that have to be aggregated using multiple operators, being sliding windows one of the most common abstractions used to process data in real-time. To satisfy the above-mentioned demands, efficient stream processing techniques that aggregate data with minimal computational cost need to be developed. However, data analytics might require to aggregate extensive windows of data. Approximate computing has been a central paradigm for decades in data analytics in order to improve the performance and reduce the needed resources, such as memory, computation time, bandwidth or energy. In exchange for these improvements, the aggregated results suffer from a level of inaccuracy that in some cases can be predicted and constrained. This doctoral thesis aims to demonstrate that it is possible to have constant-time and memory efficient aggregation functions with approximate computing mechanisms for constrained environments. In order to achieve this goal, the work has been structured in three research challenges. First we introduce a runtime to dynamically construct data stream processing topologies based on user-supplied code. These dynamic topologies are built on-the-fly using a data subscription model de¿ned by the applications that consume data. The subscription-based programing model enables multiple users to deploy their own data-processing services. On top of this runtime, we present the Amortized Monoid Tree Aggregator general sliding window aggregation framework, which seamlessly combines the following features: amortized O(1) time complexity and a worst-case of O(log n) between insertions; it provides both a window aggregation mechanism and a window slide policy that are user programmable; the enforcement of the window sliding policy exhibits amortized O(1) computational cost for single evictions and supports bulk evictions with cost O(log n); and it requires a local memory space of O(log n). The framework can compute aggregations over multiple data dimensions, and has been designed to support decoupling computation and data storage through the use of distributed Key-Value Stores to keep window elements and partial aggregations. Specially motivated by edge computing scenarios, we contribute Approximate and Amortized Monoid Tree Aggregator (A2MTA). It is, to our knowledge, the first general purpose sliding window programable framework that combines constant-time aggregations with error bounded approximate computing techniques. A2MTA uses statistical analysis of the stream data in order to perform inaccurate aggregations, providing a critical reduction of needed resources for massive stream data aggregation, and an improvement of performance.La ràpida evolució de les plataformes d'anàlisi de dades ha resultat en un increment de la demanda de processament de fluxos continus de dades en temps real. Des de la internet de les coses fins al monitoratge de telemetria generada en grans servidors, una demanda recurrent per escenaris emergents es la necessitat de processar grans quantitats de dades amb latències molt baixes, generalment fent el processat de les dades tant a prop dels origines com sigui possible. Les dades son generades com a fluxos continus per dispositius que utilitzen una varietat de localitzacions i protocols. Aquests processat de les dades s pot fer en temps real amb les transformacions efectuant-se al vol, i en aquest cas la utilització de plataformes de processat d'streams és necessària. Les plataformes de processat d'streams cal que absorbeixin pics de freqüència de dades. Les dades es generen com a series temporals que s'agreguen fent servir multiples operadors, on les finestres són l'abstracció més habitual. Per a satisfer les baixes latències i maleabilitat requerides, els operadors necesiten tenir un cost computacional mínim, inclús amb extenses finestres de dades per a agregar. La computació aproximada ha sigut durant decades un paradigma rellevant per l'anàlisi de dades on cal millorar el rendiment de diferents algorismes i reduir-ne el temps de computació, la memòria requerida, l'ample de banda o el consum energètic. A canvi d'aquestes millores, els resultats poden patir d'una falta d'exactitud que pot ser estimada i controlada. Aquesta tesi doctoral vol demostrar que es posible tenir funcions d'agregació pel processat d'streams que tinc un cost de temps constant, sigui eficient en termes de memoria i faci ús de computació aproximada. Per aconseguir aquests objectius, aquesta tesi està dividida en tres reptes. Primer presentem un entorn per a la construcció dinàmica de topologies de computació d'streams de dades utilitzant codi d'usuari. Aquestes topologies es construeixen fent servir un model de subscripció a streams, en el que les aplicación consumidores de dades amplien les topologies mentre s'estan executant. Aquest entorn permet multiples entitats ampliant una mateixa topologia. A sobre d'aquest entorn, presentem un framework de propòsit general per a l'agregació de finestres de dades anomenat AMTA (Amortized Monoid Tree Aggregator). Aquest framework combina: temps amortitzat constant per a totes les operacions, amb un cas pitjor logarítmic; programable tant en termes d'agregació com en termes d'expulsió d'elements de la finestra. L'expulsió massiva d'elements de la finestra es considera una operació atòmica, amb un cost amortitzat constant; i requereix espai en memoria local per a O(log n) elements de la finestra. Aquest framework pot computar agregacions sobre multiples dimensions de dades, i ha estat dissenyat per desacoplar la computació de les dades del seu desat, podent tenir els continguts de la finestra distribuits en diferents màquines. Motivats per la computació en l'edge (edge computing), hem contribuit A2MTA (Approximate and Amortized Monoid Tree Aggregator). Des de el nostre coneixement, es el primer framework de propòsit general per a la computació de finestres que combina un cost constant per a totes les seves operacions amb tècniques de computació aproximada amb control de l'error. A2MTA fa us d'anàlisis estadístics per a poder fer agregacions amb error limitat, reduint críticament els recursos necessaris per a la computació de grans quantitats de dades

    Domain-Specific Multi-Modeling of Security Concerns in Service-Oriented Architectures

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    As a common reference for many in-development standards and execution frameworks, special attention is being paid to Service-Oriented Architectures. SOAs modeling, however, is an area in which a consensus has not being achieved. Currently, standardization organizations are defining proposals to offer a solution to this problem. Nevertheless, until very recently, non-functional aspects of services have not been considered for standardization processes. In particular, there exists a lack of a design solution that permits an independent development of the functional and non-functional concerns of SOAs, allowing that each concern be addressed in a convenient manner in early stages of the development, in a way that could guarantee the quality of this type of systems. This paper, leveraging on previous work, presents an approach to integrate security-related non-functional aspects (such as confidentiality, integrity, and access control) in the development of services

    Flint for safer smart contracts

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    The Ethereum blockchain platform supports the execution of decentralised applications or smart contracts. These typically hold and transfer digital currency to other parties on the platform; however, they have been subject to numerous attacks due to the unintentional introduction of bugs. Over a billion dollars worth of currency has been stolen since its release in July 2015. As smart contracts cannot be updated after deployment, it is imperative that the programming language supports the development of robust contracts. We propose Flint, a new statically-typed programming language specifically designed for writing robust smart contracts. Flint's features enforce the writing of safe and predictable code. To encourage good practices, we introduce protection blocks. Protection blocks restrict who can run code and when (using typestate) it can be executed. To prevent vulnerabilities relating to the unintentional loss of currency, Flint Asset traits provide safe atomic operations, ensuring the state of contracts is always consistent. Writes to state are restricted, simplifying reasoning about smart contracts

    The Evolution of Smart Buildings: An Industrial Perspective of the Development of Smart Buildings in the 2010s

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    Over the course of the 2010s, specialist research bodies have failed to provide a holistic view of the changes in the prominent reason (as driven by industry) for creating a smart building. Over the 2010s, research tended to focus on remaining deeply involved in only single issues or value drivers. Through an analysis of the author’s peer reviewed and published works (book chapters, articles, essays and podcasts), supplemented with additional contextual academic literature, a model for how the key drivers for creating a smart building have evolved in industry during the 2010s is presented. The critical research commentary within this thesis, tracks the incremental advances of technology and their application to the built environment via academic movements, industrial shifts, or the author’s personal contributions. This thesis has found that it is demonstrable, through the chronology and publication dates of the included research papers, that as the financial cost and complexity of sensors and cloud computing reduced, smart buildings became increasingly prevalent. Initially, sustainability was the primary focus with the use of HVAC analytics and advanced metering in the early 2010s. The middle of the decade saw an economic transformation of the commercial office sector and the driver for creating a smart building was concerned with delivering flexible yet quantifiably used space. Driven by society’s emphasis on health, wellbeing and productivity, smart buildings pivoted their focus towards the end of the 2010s. Smart building technologies were required to demonstrate the impacts of architecture on the human. This research has evidenced that smart buildings use data to improve performance in sustainability, in space usage or for humancentric outcomes

    Algorithm of Remote Monitoring ECG Using Mobile Phone: Conception and Implementation

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    Researches in the medical remote monitoring at home have taken a great consideration and care in wireless communication these last years. The set of these researches is linked to the aging population and lack of infrastructures of reception for persons exposed to accident’s risks in their daily life or degradation of their health in short time. The principal objective is to permit a taking off for medical and social dependant people as aged ones, handicapped, in order to the adaptation with their environment domestically and make up their incapacities. In this case, it is indispensable to make a diagnostic in a real time and managed really the given data of patients between medical actors with the permanent security insurance of highly risky patients. Furthermore, the need to make a speed diagnostic of patients and to detect their health state with efficacy permits the gain of time in their taking off. The stakes of setting up such systems are numerous, so much for patients, medical staff and the society generally. So, it is useful to detect and prevent the occurrence of critical situations of a person at home, implying the transmission of message and alarms to actors concerned and ready to intervene in case of necessity. Our attention has been focused on the choice of a relevant work. It concerns an application on a mobile terminal (MIDlet) for monitoring patient in a non-hospital setting. This paper recalls a complete architecture of an economic wireless transmission system with the implementation of an effective algorithm, adapted to the mobile terminal, allowing to the doctor to have the results of analysis of ECG data wirelessly

    OSA/PARLAY on a SIP network

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