1,721,079 research outputs found
Context-aware service composition and delivery in NGSONs over SDN
Full text linkNGSON is an IEEE sponsored effort to standardize an open service ecosystem where different stakeholders may cooperate to satisfy users' ever changing requirements by composing and delivering services dynamically across different service providers and network operators' domains. A main distinguishing feature of NGSON is context awareness, that is, the capability of collecting, processing, and using context information to drive the interactions of the NGSON overlay nodes with service and network operators' infrastructures for guaranteeing an optimal user experience. Recent advances in network control and management technologies, such as SDN, NFV, and service-oriented networking paradigms, are expected to make the network effectively able to cope with application service requirements in a more flexible, timely, and agile manner. In this article we discuss how NGSON, which already incorporates several aspects of virtualization, could take advantage of network virtualization mechanisms and programmable traffic steering capabilities to enhance and effectively support context-aware service composition along with adaptive service delivery. We propose an architectural model for NGSON that leverages these novel network service control capabilities and illustrate through a use case how this model could effectively be put into operation
From sectoral industrial composition to employment and reverse. The italian case
Full text linkThe diffusion of knowledge among firms and workers, which, in turn, depends on the nature of the knowledge itself and the relatedness or unrelatedness of the industrial composition, is an essential driver for the growth and employment of territories. The proximity between related industries allows for faster diffusion of specific knowledge, as happens in the Marshall-Arrow-Romer (MAR) theory of externalities (agglomeration) and Jacobs’s theory of knowledge transmission. The literature (notably the Evolutionary Economic Geography one, EEG) has empirically investigated the relationship between employment (or GDP) and some measures of industrial composition (e.g., the related and unrelated variety). In this paper, we contribute to the literature in two ways. First, we propose a more coherent use of entropy indexes to measure the relatedness or unrelatedness of industries in an economy. Second, we empirically investigate the nexus between industrial composition and employment level by exploiting these measures. Unlike the existing literature, we argue that such a nexus could be circular. For such a reason, an empirical investigation using a spatial vector autoregressive (SpVAR) model will be performed for the Italian economy at the provincial level. The results show that such a circular nexus exists, shedding new light on the debate
A Service-Oriented Approach for Dynamic Chaining of Virtual Network Functions over Multi-Provider Software-Defined Networks
Full text linkEmerging technologies such as Software-Defined Networks (SDN) and Network Function Virtualization (NFV) promise to address cost reduction and flexibility in network operation while enabling innovative network service delivery models. However, operational network service delivery solutions still need to be developed that actually exploit these technologies, especially at the multi-provider level. Indeed, the implementation of network functions as software running over a virtualized infrastructure and provisioned on a service basis let one envisage an ecosystem of network services that are dynamically and flexibly assembled by orchestrating Virtual Network Functions even across different provider domains, thereby coping with changeable user and service requirements and context conditions. In this paper we propose an approach that adopts Service-Oriented Architecture (SOA) technology-agnostic architectural guidelines in the design of a solution for orchestrating and dynamically chaining Virtual Network Functions. We discuss how SOA, NFV, and SDN may complement each other in realizing dynamic network function chaining through service composition specification, service selection, service delivery, and placement tasks. Then, we describe the architecture of a SOA-inspired NFV orchestrator, which leverages SDN-based network control capabilities to address an effective delivery of elastic chains of Virtual Network Functions. Preliminary results of prototype implementation and testing activities are also presented. The benefits for Network Service Providers are also described that derive from the adaptive network service provisioning in a multi-provider environment through the orchestration of computing and networking services to provide end users with an enhanced service experience
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Latency-aware composition of Virtual Functions in 5G
No full textThe adoption of the virtualization paradigm in both computing and networking domains portends a landscape of heterogeneous service capabilities and resources pervasively distributed and interconnected and deeply integrated through the 5G network infrastructure. In this service ecosystem, dynamic service demand can be flexibly and elastically accomplished by composing heterogeneous services provisioned over a distributed and virtualized resource infrastructure. Indeed, with the term Virtual Functions we refer to virtual computing as well as network service capabilities (e.g., routers and middlebox functions provided as Virtual Network Functions). In order to cope with the increasingly resource intensive demand, these virtual functions will be deployed in distributed clusters of small-scale datacenters typically located in current exchanges at the network edge and will supplement those deployed in traditional large cloud datacenters. In this work we formulate the problem of composing, computing and networking Virtual Functions to select those nodes along the path that minimizes the overall latency (i.e. network and processing latency) in the above mentioned scenario. The optimization problem is formulated as a Resource Constrained Shortest Path problem on an auxiliary layered graph accordingly defined. The layered structure of the graph ensures that the order of VFs specified in the request is preserved. Additional constraints can be also taken into account in the graph construction phase. Finally, we provide a use case preliminary evaluation of the proposed model
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Cross-Functional resource orchestration in optical telco clouds
No full textWith communication endpoints given by mobile user devices and by elastically provisioned virtual resources, one of the main challenge of cloud-based service provisioning is to deploy a coordinated control of both data center and network resources in order to provide adaptive data delivery services and adequate service experience to cloud users. In this regard, flexible optical networks can play a fundamental role in telco clouds to effectively address bandwidth requirements of elastic data center operations. This paper presents a cross-functional orchestration platform able to coordinate the provision of cloud-based services with multi-granular data delivery services across flexible optical network. The architectural design is described along with orchestration policies that are compared in terms of blocking ratio of service requests against the level of utilization of network links
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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