1,720,965 research outputs found
SLA-based optimization of energy and migration cost on openflow platform
No full textPlatform as a Service (PaaS) is one of the cloud computing services for offering virtual operating systems to clients. The rave over cloud computing services is due to its obvious advantages compared to traditional network services. Those advantages include: high computational power, high scalability, and lower requirements needed from end devices. However, one of the challenges for cloud service providers is related to Service Level Agreements (SLAs), which specify constraints on the provided Quality of Service. The profit of the cloud provider depends on how they meet the SLA. Generally, the greater the size of the datacenter, the better performance clients can achieve. Moreover, the energy cost related to the size of the datacenter results in basic trade-offs with client satisfaction. In this thesis, a dynamic and migration algorithm is proposed to minimize the cost of energy in consideration of SLAs. An emerging Software Defined Networks (SDN) technology called OpenFlow technology is utilized in our local testbed. Simulation and experimental results demonstrate that the efficiency of the resource usage and reduced power consumption of the cloud can coexist with SLAs while keeping the cost of penalties and power consumption to minimum
Cloud based Autonomic service monitoring in an OpenFlow network
No full textThe area of Future Internet research focuses on developing a new network with similar magnitude as today\u27s Internet but with more demanding and complex design goals and specifications. It strives to solve the issues identified in today\u27s Internet, by capitalizing on the advantages of emerging new technologies in the area of computer networking such as OpenFlow, Autonomic computing or Cloud Computing. By combining these technologies and applying them together significant progress is made in the development of an enhanced, more complex, but also more secure, reliable and scalable Internet. This thesis focuses on the development of a complete system, designed with the new requirements of the Future Internet in mind, which builds on OpenFlow, Autonomic Computing and Cloud Computing technologies, and aims to provide, monitor and enhance the very popular video streaming service of today\u27s Internet. One of the main goals is to show, how such a system can function under unstable, changing network conditions, how it can dynamically learn its environment recognize potential service degradation problems and react to these in an autonomic manner without the need for human intervention
Efficient artificial intelligence-based localization algorithms for Wireless Sensor Networks
No full textRecent advancement in wireless communications and electronics has enabled the development of Wireless Sensor Networks (WSN). WSNs are being deployed in a variety of location-aware applications, where the measurement of data is meaningless without accurate location. Many localization algorithms have been proposed in order to increase the accuracy and minimize the cost requirements. Artificial intelligence techniques such as Fuzzy logic and neural networks can be utilized as effective methods to satisfy these requirements. In this thesis, we present two efficient artificial intelligence-based localization algorithms for WSNs. In the first algorithm, we implement a Sugeno-type fuzzy system with a collaborative communication feedback to achieve an accurate and cost effective two- dimensional (2D) localization system. In the second algorithm, the idea of the 2D localization using neural network is extended to achieve a three-dimensional (3D) localization with simplicity, location accuracy, and low cost. The proposed approach is also able to localize mobile nodes with unpredictable movement patterns. The simulation results depict the performance and the effectiveness of each approach. Keywords: Wireless sensor network, Fuzzy logic, Neural networks, Localization, Location accuracy, Cost effective, Mobility
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Quality of service support in optical burst switching
No full textNext-generation high-speed Internet backbone networks are required to support a broad range of emerging applications which may not only require significant bandwidth, but also have strict Quality of Service (QoS) requirements. Optical Burst Switching (OBS) is a promising switching technology for the next-generation networks which attempts to address the problem of efficiently allocating resources for Internet traffic. A key challenge in OBS is how to reduce burst loss probability. In this paper, we evaluate two simple QoS models to support different classes of traffic. The simulation results illustrate the performance of an OBS network when different models of QoS are supported. We primarily evaluate the impact on high loss rate in OBS networks when using these models
Variations on the Author
Get PDF“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
Get PDFWe 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
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe 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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