1,720,969 research outputs found
A new Cu(II) three-dimensional network with 4,4′-oxybis benzoic acid: structural diversity, EPR, and magnetism
No full textThe copper derivative [Cu4(oba)4(H2O)4]∙H2On(1) has been hydro(solvo)thermally synthesized by combining flexible 4,4′-oxybis benzoic acid (oba) and divalent copper nitrate. As a result of the potential coordination modes of carboxylate oxygens from the oba ligand, the aforementioned complex leads to the formation of an interesting 3D framework, as evidenced by single-crystal X-ray diffractometry. Concerning the topology in 1, the dimers [Cu2C4O8] are nodes of a 5-fold 4-connected uninodal net of the type lvt, with point symbol 42.84 and vertex symbol [4.4.84.84.88.88]. The encapsulation of the copper coordination polymer displays a moderate luminescent property. On temperature-dependent magnetic study, it reveals that the magnetic behaviour of 1 can be associated to a strong antiferromagnetic coupling between the two Cu(II) ions
Concept-Aware Ranking: Teaching an Old Graph New Moves
No full textRanking algorithms for web graphs, such as PageRank and HITS, are typically utilized for graphs where a node represents a unique URL (Webpage) and an edge is an explicitly-defined link between two such nodes. In addition to the link structure itself, additional information about the relationship between nodes may be available. For example, anchor text in a Web graph is likely to provide information about the underlying concepts connecting URLs. In this paper, we propose an extension to the Web graph model to take into account conceptual information encoded by links in order to construct a new graph which is sensitive to the conceptual links between nodes. By extracting keywords and recurring phrases from the anchor tag data, a set of concepts is defined. A new definition of a node (one which encodes both an URL and concept) is then leveraged to create an entirely new Web graph, with edges representing both explicit and implicit conceptual links between nodes. In doing so, inter-concept relationships can be modeled and utilized when using graph ranking algorithms. This improves result accuracy by not only retrieving links which are more authoritative given a users' context, but also by utilizing a larger pool of web pages that are limited by concept-space, rather than keyword-space. This is illustrated using webpages from the University of Minnesota's College of Liberal Arts websites.DeLong, Colin; Mane, Sandeep; Srivastava, Jaideep. (2006). Concept-Aware Ranking: Teaching an Old Graph New Moves. Retrieved from the University Digital Conservancy, https://hdl.handle.net/11299/215692
Who Thinks Who Knows Who? Socio-cognitive Analysis of Email Networks
No full textInterpersonal interaction plays an important role in organizational dynamics, and understanding these interaction networks is a key issue for any organization, since these can be tapped to facilitate various organizational processes. However, the approaches of collecting data about them using surveys/interviews are fraught with problems of scalability, logistics and reporting biases, especially since such surveys may be perceived to be intrusive. Widespread use of computer networks for organizational communication provides a unique opportunity to overcome these difficulties and automatically map the organizational networks with a high degree of detail and accuracy. This paper describes an effective and scalable approach for modeling organizational networks by tapping into an organization's email communication. The approach models communication between actors as non-stationary Bernoulli trials and Bayesian inference is used for estimating model parameters over time. This approach is useful for socio-cognitive analysis (who knows who knows who) of organizational communication networks. Using this approach, novel measures for analysis of (i) closeness between actors' perceptions about such organizational networks (agreement), (ii) divergence of an actor's perceptions about organizational network from reality (misperception) are explained. Using the Enron email data, we show that these techniques provide sociologists with a new tool to understand organizational networks.Pathak, Nishith; Mane, Sandeep; Srivastava, Jaideep. (2006). Who Thinks Who Knows Who? Socio-cognitive Analysis of Email Networks. Retrieved from the University Digital Conservancy, https://hdl.handle.net/11299/215708
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
Network Size Estimation In A Peer-to-Peer Network
No full textThe emergence of peer-to-peer networks over the last decade has changed user's perspective about information available on the Web. But, with thousand of nodes joining and leaving a peer-to-peer network within a short span of time, it has become practically impossible for a node (or peer) to keep track of complete network. Often times, however, a node needs to at least have an estimate of number of nodes in such a network. For example, in determining time-to-live for a search query packet, a node must have a good estimate of network size. Previous deterministic approaches require a complete walk on the network, since such networks usually lack a central authority. Such approaches hence do not scale well to large networks. A few approaches, which collect partial information about the network, have been proposed as an alternative to address the scalability issues. This paper presents a novel approach for size estimation of a peer-to-peer network. The basic idea is to sample nodes in the network and then using this partial information about the network, an estimate of the network size is obtained using capture-recapture method. The capture-recapture method is a statistical method, which has been widely used for estimation of size of a closed population in oceanography and epidemiology. For a better estimate, the capture-recapture method requires two or more random (independent) samplings (sets of detected nodes) of the network. In our case, for independent sampling, we use random walks on the peer-to-peer network, since a random walk can achieve same statistical properties as independent samplings for a peer-to-peer network (see Gkantsidis et al [1]). Experimental results show that the proposed random walk based capture-recapture approach gives a good estimate of network size. In addition, results of using proposed method as well as three other size estimation methods on scale-free and random networks shows that the former algorithm gives a better estimate (lesser error) with a slight overhead on computation. This research motivates further study of estimation techniques for open networks (i.e. networks whose size changes during the estimation process).Mane, Sandeep; Mopuru, Sandeep; Mehra, Kriti; Srivastava, Jaideep. (2005). Network Size Estimation In A Peer-to-Peer Network. Retrieved from the University Digital Conservancy, https://hdl.handle.net/11299/215671
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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