1,721,085 research outputs found
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
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
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
Distributed Algorithms for Online Coordination in Wireless Sensor Networks
No full text198 pg.With the rapid development of large-scale wireless sensor networks in the past few years, we expect the embedded sensors to be integrated smoothly with other mobile embedded devices. In this dissertation, we consider the following model of a hybrid network with both static and mobile nodes. There are pervasive static sensor nodes embedded in the environment to gather real-time data. The mobile nodes can be either robots with controlled mobility to aid the network operation and repair dysfunctional network components, or users of the sensor network that demand real-time knowledge gathered by the sensor nodes, or robots/users that use the sensor network as a communication infrastructure, or a mixture of the above. The specific scenarios include, but are not limited to, online resource management and allocation, maintaining group communication and coordination of mobile agents, and efficient and resilient routing schemes. To solve these problems, we introduce a framework to manage the efficient and highly selective information flow between the sensor nodes and the mobile nodes. This framework involves the following components: ?? We extract a hierarchical well separated tree (HST) to approximate the shortest path metric of the static sensor network. ?? With the HST, we allow spontaneous, distributed matching between users that may emerge anywhere and the resources available in the network. ?? We also show that in the same framework, we can coordinate mobile users by maintaining an approximate minimum Steiner tree with modest communication cost. ?? By using two or multiple HSTs, we also show how to support low-stretch routing that is also resilient to in-transit link failures. In addition to the above HST framework, we develop the compact conformal map for greedy routing in wireless mobile sensor networks. The map is only dependent on the network domain and is independent of the network connectivity. This is the first practical solution for using virtual coordinates for greedy routing in a sensor network and could be easily extended to the case of a mobile network.Advisor(s): Gao, Jie ; Das, Samir. Committee Member(s): Gu, Xianfeng ; Hong, Sangjin.Stony Brook University Libraries. SBU Graduate School in Department of Computer Science. Charles Taber (Dean of Graduate School)
Traffic Driven Analysis of Cellular and WiFi Networks
No full text168 pg.Since the days Internet traffic proliferated, measurement, monitoring and analysis of network traffic have been critical to not only the basic understanding of large networks, but also to seek improvements in resource management, traffic engineering and security. At the current times traffic in wireless local and wide area networks are facing similar upsurge. This calls for a similar vigor in traffic analysis studies. This thesis focuses on several traffic analysis studies in both cellular data networks and WiFi LANs. The broad goal is (i) to improve the understanding of the traffic dynamics, to explore structures in the traffic to help cost-effective monitoring and building of new traffic management strategies --- in the context of cellular networks, and (ii) understanding the interference properties and detecting misbehavior --- in the context of WiFi networks. We first use a large-scale data set collected inside a nationwide 3G cellular data network and conduct a detailed measurement analysis of network resource usage and subscriber behavior. We characterize subscriber mobility and temporal activity patterns and identify their relation to traffic volume. We also investigate how efficiently radio resources are used by different subscribers as well as by different applications. Our analysis using different statistical techniques shows existence of significant spatial correlation in radio resource usage in the base stations. We also use the concept of Granger Causality to understand the underlying functional connectivity and flow of influence in the network. Broadly, our observations deliver important insights into network-wide resource usage. Next, we propose a new traffic management technique for cellular data networks to improve networks' resource crisis situation in the face of exponential increase in mobile data traffic volume. Here we consider the existence of a higher-layer, agent-based scheduling system that could potentially delay scheduling of low priority flows at peak loads. The priorities are assumed to be user or application tagged, either automatically or manually. The general goal is to potentially move the low priority flows in time and space opportunistically to reduce the overall resource needs. We develop and evaluate two scheduling schemes. Simulation results using our large-scale cellular network trace data show the potential of these approaches in reducing base station resource requirements. Next, we present a scalable traffic measurement and monitoring technique for cellular data networks. We use a machine learning technique to learn the underlying conditional dependence structure in the base station traffic loads to show how such probabilistic models can be used to reduce the traffic monitoring efforts. The broad goal is to exploit the model to develop a spatial sampling technique that estimates the loads on all the base stations based on actual measurements only on a small subset of base stations. To understand the tradeoff between the accuracy and monitoring complexity better, we also study the use of this modeling approach on real applications. Two applications are studied --- energy saving and opportunistic scheduling. They show that load estimation via such modeling is quite effective in reducing the monitoring burden. In the last part of our thesis, we turn our attention to WiFi networks. We present a tool to estimate the interference between nodes and links in a live WiFi network by passive monitoring of wireless traffic. Our approach requires deploying multiple sniffers across the network to capture wireless traffic traces. These traces are then analyzed using a machine learning approach to infer the carrier-sense relationship between network nodes. We also demonstrate an important application of this tool--detection of selfish carrier-sense behavior. This is based on identifying any asymmetry in carrier-sense behavior between node pairs and finding multiple witnesses to raise confidence. We evaluate the tool using extensive experiments and simulation which demonstrate the effectiveness of both the applications.Advisor(s): Das, Samir R. Committee Member(s): Ortiz, Luis ; Gupta, Himanshu ; Buddhikot, Milind.Stony Brook University Libraries. SBU Graduate School in Department of Computer Science. Charles Taber (Dean of Graduate School)
Design and Performance Considerations for Vehicular Network Access
No full text155 pg.The `Connected Car' concept has gained considerable interest in recent years from the car manufacturers. The `Connected Car' is envisioned to be connected to the Internet over wireless data networks enabling services like remote vehicle monitoring and diagnostics, real-time navigational assistance, sensor data collection and access to Internet media on the go. Although cellular data connectivity is largely ubiquitous in the developed world, it provides limited bandwidth and is quite expensive. Also, licensed spectrum is a scarce resource and cellular network providers are constantly faced with the challenge of providing good performance to an ever increasing user base. We posit that road-side WiFi networks have the potential to provide high bandwidth and inexpensive wireless connectivity to moving vehicles and can be beneficially used for offloading data away from the cellular data networks. In this dissertation we perform measurement analysis to show feasibility of such offloading. We also develop techniques to show how such offloading could be performed. We follow up with further techniques to improve vehicular WiFi access. First, we investigate a hybrid wireless access network design that integrates 3G and WiFi networks under vehicular mobility. The goal is to shift the load from the expensive 3G networks to the less expensive WiFi network without hurting the user experience. Instead of simply striping data over two network connections, we develop a utility and cost-based formulation that decides the right amount of load that can be put on the 3G network to maximize users benefit. We develop and experiment with a scheduler to do this. We show via extensive measurements on a metro-scale WiFi network and a nationwide 3G network that the hybrid design is able to deliver much superior mobile video streaming experience for the user while reducing the load on the 3G network by three-fourth. Then, we focus our attention to improving vehicular WiFi performance. We argue that mobility and connectivity information along drives can be predicted with good accuracy using historical information such as GPS tracks and RF fingerprints. We exploit such information to develop new handoff and data transfer strategies to reduce connection establishment latency and to improve download performance. Next, we develop Brave - an SNR-based rate adaptation algorithm for vehicular WiFi access environments. Because of the highly dynamic nature of the outdoor vehicular WiFi link, BRAVE only considers short history to make rate selection decisions and out-performs other well-known frame-based and SNR-based algorithms. Finally, we show how a multi-radio multi-vehicle system can improve the perceived coverage and throughput performance of vehicular WiFi clients. Using a metro-scale WiFi deployment we experimentally demonstrate that with intelligent access point filtering, a single multi-radio vehicular client can effectively mask connection establishment latencies completely and using another such vehicle as a relay can mask coverage holes to a large extent.Advisor(s): Das, Samir R. Committee Member(s): Gupta, Himanshu ; Wong, Jennifer ; Tang, Wendy.Stony Brook University Libraries. SBU Graduate School in Department of Computer Science. Charles Taber (Dean of Graduate School)
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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