1,721,125 research outputs found
Intelligent caching in information-centric networks
No full textCaching has become an integral part of the Internet to improve the performance of services and applications that rely on the Internet as a medium to disseminate information and content. Information-centric networks (ICN) is an alternative paradigm to reconstruct the Internet that puts information and content as the first class citizens. Under such paradigm, caching is natively supported in the network layer. In this thesis, we address the inefficiencies resulting from the default caching strategy employed by ICN forwarders, and discuss the design and implementation of two caching schemes that improve caching in the spatial and temporal dimensions. In the spatial dimension, we introduce cooperative caching. Forwarders share their caches with one-hop neighbors while evicting redundant cache entries. We make several design decisions to make this scheme practical to implement. In the temporal dimension, we explore the use of machine learning methods to construct a model that is used to predict future content popularity based on past history, and design a cache algorithm that uses predicted popularity to make cache decisions. We evaluate the caching schemes by extensive emulations of network traffic on emulated network topologies.</p
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
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
Core-PC: A class of correlative power control algorithms for single channel mobile ad hoc networks
No full textIn this paper we study the correlations that exist between the required transmission power of RTS, CTS, DATA and ACK frames to guarantee a successful 4-way handshake in wireless ad hoc networks based on the IEEE 802.11 distributed coordination function (DCF). From these correlations, and starting from a set of different initial conditions, we can derive a class of power controlled media access control (MAC) algorithms for single channel ad hoc networks based on the existing IEEE 802.11 DCF. From substantial simulations of the different algorithms and comparison to some prominent alternatives, we come to a conclusion that contradicts the intuitively sound, commonly held belief which states that sending control frames at maximum power - to reduce interference on the long data frames - then, the ensuing long data frames at a lower, yet sufficient power level decreases power consumption per carried bit.</p
Energy Efficient Medium Access with Interference Mitigation in LTE Femtocell Networks
No full textWith the rapidly increasing number of deployed LTE femtocell base stations (FBS), energy consumption of femtocell networks has become a serious environmental issue. Therefore, energy-efficient protocols are needed to balance the trade-off between energy saving and bandwidth utilization. The key component of the desired protocol to prevent both energy and bandwidth waste is interference mitigation, which, nevertheless, most previous work has failed to properly consider. To this end, in this paper, we manipulate user equipment (UE) association and OFDMA scheduling with a combination of interference mitigation. Recognizing the NP-hardness of the problem, we propose two distributed algorithms with guaranteed convergence. Extensive simulations show that our algorithms outperform the alternative algorithms in multiple metrics such as utility, power consumption, and convergence speed
Next-generation WDM network design and routing: Introduction to the feature issue
No full textFeature Issue on Next-Generation WDM Network Design and Routing (WDMN) The ever-increasing volume of Internet traffic is the major driver behind the increased efforts toward designing switches, routers, and new techniques and technologies that are capable of sustaining such tremendous demands. Optical networking and wavelength-division multiplexing (WDM) have emerged in the past decade as the technology and the technique of choice for efficiently exploiting the large bandwidth offered by optical devices at a very competitive cost per carried bit. To bring such technologies all the way from mere hardware to user-ready devices, there remains a large gap to be filled with protocols, frameworks, algorithms, and designs that make effective and efficient use of this optical fiber bandwidth. Research in the area has been focused recently on many aspects of optical networks. Of particular interest to this feature issue of JON are some aspects that can grossly be sorted as follows: teletraffic techniques; routing and wavelength assignment in circuit-switched WDM networks; optical packet and burst switching and performance-related issues; GMPLS and IP traffic transport in WDM networks; topology configuration, path protection, network architecture, and related issues. To cover theses areas, 15 papers have been carefully selected through a rigorous peer-review process. Seven of these are invited papers that also underwent review to help enhance the quality of the presentation. The remaining 8 papers were selected among 31 submitted.</p
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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