223 research outputs found

    Software-Driven and Virtualized Architectures for Scalable 5G Networks

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    In this dissertation, we argue that it is essential to rearchitect 4G cellular core networks–sitting between the Internet and the radio access network–to meet the scalability, performance, and flexibility requirements of 5G networks. Today, there is a growing consensus among operators and research community that software-defined networking (SDN), network function virtualization (NFV), and mobile edge computing (MEC) paradigms will be the key ingredients of the next-generation cellular networks. Motivated by these trends, we design and optimize three core network architectures, SoftMoW, SoftBox, and SkyCore, for different network scales, objectives, and conditions. SoftMoW provides global control over nationwide core networks with the ultimate goal of enabling new routing and mobility optimizations. SoftBox attempts to enhance policy enforcement in statewide core networks to enable low-latency, signaling-efficient, and customized services for mobile devices. Sky- Core is aimed at realizing a compact core network for citywide UAV-based radio networks that are going to serve first responders in the future. Network slicing techniques make it possible to deploy these solutions on the same infrastructure in parallel. To better support mobility and provide verifiable security, these architectures can use an addressing scheme that separates network locations and identities with self-certifying, flat and non-aggregatable address components. To benefit the proposed architectures, we designed a high-speed and memory-efficient router, called Caesar, for this type of addressing schemePHDComputer Science & EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttps://deepblue.lib.umich.edu/bitstream/2027.42/146130/1/moradi_1.pd

    Achieving reliable and enhanced communication in vehicular ad hoc networks (VANETs)

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    A thesis submitted to the University of Bedfordshire in partial fulfilment of the requirement for the degree of Doctor of PhilosophyWith the envisioned age of Internet of Things (IoTs), different aspects of Intelligent Transportation System (ITS) will be linked so as to advance road transportation safety, ease congestion of road traffic, lessen air pollution, improve passenger transportation comfort and significantly reduce road accidents. In vehicular networks, regular exchange of current position, direction, speed, etc., enable mobile vehicle to foresee an imminent vehicle accident and notify the driver early enough in order to take appropriate action(s) or the vehicle on its own may take adequate preventive measures to avert the looming accident. Actualizing this concept requires use of shared media access protocol that is capable of guaranteeing reliable and timely broadcast of safety messages. This dissertation investigates the use of Network Coding (NC) techniques to enrich the content of each transmission and ensure improved high reliability of the broadcasted safety messages with less number of retransmissions. A Code Aided Retransmission-based Error Recovery (CARER) protocol is proposed. In order to avoid broadcast storm problem, a rebroadcasting vehicle selection metric η, is developed, which is used to select a vehicle that will rebroadcast the received encoded message. Although the proposed CARER protocol demonstrates an impressive performance, the level of incurred overhead is fairly high due to the use of complex rebroadcasting vehicle selection metric. To resolve this issue, a Random Network Coding (RNC) and vehicle clustering based vehicular communication scheme with low algorithmic complexity, named Reliable and Enhanced Cooperative Cross-layer MAC (RECMAC) scheme, is proposed. The use of this clustering technique enables RECMAC to subdivide the vehicular network into small manageable, coordinated clusters which further improve transmission reliability and minimise negative impact of network overhead. Similarly, a Cluster Head (CH) selection metric ℱ(\u1d457) is designed, which is used to determine and select the most suitably qualified candidate to become the CH of a particular cluster. Finally, in order to investigate the impact of available radio spectral resource, an in-depth study of the required amount of spectrum sufficient to support high transmission reliability and minimum latency requirements of critical road safety messages in vehicular networks was carried out. The performance of the proposed schemes was clearly shown with detailed theoretical analysis and was further validated with simulation experiments

    Desarrollo dirigido por modelos de aplicaciones móviles multiplataforma a partir de un conjunto de reglas heurísticas basadas en esquemas preconceptuales

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    ilustraciones, diagramas, tablasModel driven development (MDD) approaches aim for increasing development team productivity and decreasing software time-to-market. Such approaches comprise a set of model-to-model and model-to-text transformation rules for generating the source code based on models. Some authors propose MDD approaches for cross-platform mobile applications. So, we perform a systematic literature review looking for MDD approaches for cross-platform mobile applications, having as a result 39 primary studies grouped on 19 different MDD approaches. We observe 100.0 % approaches lack close-to-natural modeling languages, 36.8 % approaches lack design patterns, and 84.2 % lack usability features. In addition, 42.1 % approaches use out-of-date programming languages as automation result. Therefore, we propose an MDD approach for cross-platform mobile applications by using pre-conceptual schemas. Such schemas allow for guaranteeing a close-to-natural modeling language, including design patterns, and including usability features. Moreover, we complete the UN-LEND specification language as an intermediate model between pre-conceptual schemas and cross-platform mobile applications, avoiding the usage of out-of-date programming languages. Then, we design a pre-conceptual-schema-based metamodel in order to develop an MDD prototype based on the Eclipse Modeling Framework and XPAND. We propose a set of heuristic rules divided into model, view, and controller layers, having the pre-conceptual schema as a rule left-hand side, UN-LEND as an intermediate model, and Java-Android and Swift-iOS code as a rule right-hand side. We validate our approach by using a case of study about MobileSQUARE: an Android application for requirements gathering based on a question answering model. As a result, we automatically generate 90.86 % of the MobileSQUARE application by using our approach. Specifically, we observe model layer is close to be fully automated having 98.95 % as automation percentage compared to view and controller layers with 82.31 % and 84.56 % respectively. We expect researchers and software engineering practitioners increase their productivity and decrease software time-to-market based on our results. We identify some future work and challenges such as: including Programming eXperience heuristics in the resulting code (PX); allowing round-trip transformations between code, UN-LEND, and pre-conceptual schemas; including rules related to pre-conceptual schema vectors, matrices, and achievement relationships; improving controller and view layers related rules to increase the automation percentage; developing a compiler for UN-LEND models.Los enfoques de desarrollo dirigidos por modelos (MDD) tienen como objetivo aumentar la productividad del equipo de desarrollo y reducir el tiempo de comercialización del software. Algunos autores proponen enfoques MDD para aplicaciones móviles multiplataforma. Por ello, se realiza una revisión sistemática de la literatura en busca de enfoques MDD para aplicaciones móviles multiplataforma, teniendo como resultado 39 estudios primarios agrupados en 19 enfoques MDD diferentes. Se observa que el 100,0 % de los enfoques carecen de lenguajes de modelado cercanos al natural, el 36,8 % de los enfoques carecen de patrones de diseño y el 84,2 % carecen de características de usabilidad. Además, el 42,1 % de los enfoques utilizan lenguajes de programación obsoletos como resultado de la automatización. Por lo tanto, se propone un enfoque MDD para aplicaciones móviles multiplataforma mediante el uso de esquemas preconceptuales. Estos esquemas permiten garantizar un lenguaje de modelado cercano al natural, incluir patrones de diseño e incluir características de usabilidad. Además, se completa el lenguaje de especificación UN-LEND como modelo intermedio entre los esquemas preconceptuales y las aplicaciones móviles multiplataforma, evitando el uso de lenguajes de programación desfasados. Luego, se diseña un metamodelo del esquema preconceptual para desarrollar un prototipo de MDD basado en el Eclipse Modeling Framework y XPAND. Se propone un conjunto de reglas heurísticas divididas en las capas modelo, vista, y controlador, teniendo al esquema preconceptual como el lado izquierdo de la regla, UN-LEND como modelo intermedio, y el código Android Java e iOS Swift como el lado derecho de la regla. Se valida este enfoque utilizando un caso de estudio sobre MobileSQUARE: una aplicación Android para la recopilación de requisitos basada en un modelo de respuesta a preguntas. Como resultado, se genera automáticamente el 90,86 % de la aplicación MobileS-QUARE utilizando las reglas propuestas. En concreto, se observa que la capa model está cerca de la automatización total teniendo un 98,95 % como porcentaje de automatización en comparación con las capas vista y controlador con un 82,31 % y 84,56 % respectivamente. Se espera que los investigadores y los profesionales de la ingeniería del software aumenten su productividad y reduzcan el tiempo de comercialización del software basándose en estos resultados. Como resultado de esta Tesis de Maestría, se identifican algunas propuestas y retos futuros como: incluir heurísticas de Experiencia del Programador (PX) en el código resultante; permitir las transformaciones de ida y vuelta entre código, UN-LEND y los esquemas preconceptuales; incluir reglas relacionadas con los vectores, la matrices y las relaciones de logro de los esquemas preconceptuales; y desarrollar un compilador para los modelos UN-LEND. (Texto tomado de la fuente)MaestríaMagister en Ingeniería - Ingeniería de SistemasSoftware engineeringÁrea Curricular de Ingeniería de Sistemas e Informátic

    Flexible Application-Layer Multicast in Heterogeneous Networks

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    This work develops a set of peer-to-peer-based protocols and extensions in order to provide Internet-wide group communication. The focus is put to the question how different access technologies can be integrated in order to face the growing traffic load problem. Thereby, protocols are developed that allow autonomous adaptation to the current network situation on the one hand and the integration of WiFi domains where applicable on the other hand

    Security for network services delivery of 5G enabled device-to-device communications mobile network

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    The increase in mobile traffic led to the development of Fifth Generation (5G) mobile network. 5G will provide Ultra Reliable Low Latency Communication (URLLC), Massive Machine Type Communication (mMTC), enhanced Mobile Broadband (eMBB). Device-to-Device (D2D) communications will be used as the underlaying technology to offload traffic from 5G Core Network (5GC) and push content closer to User Equipment (UE). It will be supported by a variety of Network Service (NS) such as Content-Centric Networking (CCN) that will provide access to other services and deliver content-based services. However, this raises new security and delivery challenges. Therefore, research was conducted to address the security issues in delivering NS in 5G enabled D2D communications network. To support D2D communications in 5G, this thesis introduces a Network Services Delivery (NSD) framework defining an integrated system model. It incorporates Cloud Radio Access Network (C-RAN) architecture, D2D communications, and CCN to support 5G’s objectives in Home Network (HN), roaming, and proximity scenarios. The research explores the security of 5G enabled D2D communications by conducting a comprehensive investigation on security threats. It analyses threats using Dolev Yao (DY) threat model and evaluates security requirements using a systematic approach based on X.805 security framework. Which aligns security requirements with network connectivity, service delivery, and sharing between entities. This analysis highlights the need for security mechanisms to provide security to NSD in an integrated system, to specify these security mechanisms, a security framework to address the security challenges at different levels of the system model is introduced. To align suitable security mechanisms, the research defines underlying security protocols to provide security at the network, service, and D2D levels. This research also explores 5G authentication protocols specified by the Third Generation Partnership Project (3GPP) for securing communication between UE and HN, checks the security guarantees of two 3GPP specified protocols, 5G-Authentication and Key Agreement (AKA) and 5G Extensive Authentication Protocol (EAP)-AKA’ that provide primary authentication at Network Access Security (NAC). The research addresses Service Level Security (SLS) by proposing Federated Identity Management (FIdM) model to integrate federated security in 5G, it also proposes three security protocols to provide secondary authentication and authorization of UE to Service Provider (SP). It also addresses D2D Service Security (DDS) by proposing two security protocols that secure the caching and sharing of services between two UEs in different D2D communications scenarios. All protocols in this research are verified for functional correctness and security guarantees using a formal method approach and semi-automated protocol verifier. The research conducts security properties and performance evaluation of the protocols for their effectiveness. It also presents how each proposed protocol provides an interface for an integrated, comprehensive security solution to secure communications for NSD in a 5G enabled D2D communications network. The main contributions of this research are the design and formal verification of security protocols. Performance evaluation is supplementary

    Ninth Workshop and Tutorial on Practical Use of Coloured Petri Nets and the CPN Tools, Aarhus, Denmark, October 20-22, 2008

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    This booklet contains the proceedings of the Ninth Workshop on Practical Use of Coloured Petri Nets and the CPN Tools, October 20-22, 2008. The workshop is organised by the CPN group at the Department of Computer Science, University of Aarhus, Denmark. The papers are also available in electronic form via the web pages: http://www.daimi.au.dk/CPnets/workshop0

    CHORUS Deliverable 2.1: State of the Art on Multimedia Search Engines

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    Based on the information provided by European projects and national initiatives related to multimedia search as well as domains experts that participated in the CHORUS Think-thanks and workshops, this document reports on the state of the art related to multimedia content search from, a technical, and socio-economic perspective. The technical perspective includes an up to date view on content based indexing and retrieval technologies, multimedia search in the context of mobile devices and peer-to-peer networks, and an overview of current evaluation and benchmark inititiatives to measure the performance of multimedia search engines. From a socio-economic perspective we inventorize the impact and legal consequences of these technical advances and point out future directions of research

    Radio Communications

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    In the last decades the restless evolution of information and communication technologies (ICT) brought to a deep transformation of our habits. The growth of the Internet and the advances in hardware and software implementations modified our way to communicate and to share information. In this book, an overview of the major issues faced today by researchers in the field of radio communications is given through 35 high quality chapters written by specialists working in universities and research centers all over the world. Various aspects will be deeply discussed: channel modeling, beamforming, multiple antennas, cooperative networks, opportunistic scheduling, advanced admission control, handover management, systems performance assessment, routing issues in mobility conditions, localization, web security. Advanced techniques for the radio resource management will be discussed both in single and multiple radio technologies; either in infrastructure, mesh or ad hoc networks
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