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1.
Lutz Bornmann Rüdiger Mutz Sven E. Hug Hans-Dieter Daniel 《Journal of Informetrics》2011,5(3):346-359
This paper presents the first meta-analysis of studies that computed correlations between the h index and variants of the h index (such as the g index; in total 37 different variants) that have been proposed and discussed in the literature. A high correlation between the h index and its variants would indicate that the h index variants hardly provide added information to the h index. This meta-analysis included 135 correlation coefficients from 32 studies. The studies were based on a total sample size of N = 9005; on average, each study had a sample size of n = 257. The results of a three-level cross-classified mixed-effects meta-analysis show a high correlation between the h index and its variants: Depending on the model, the mean correlation coefficient varies between .8 and .9. This means that there is redundancy between most of the h index variants and the h index. There is a statistically significant study-to-study variation of the correlation coefficients in the information they yield. The lowest correlation coefficients with the h index are found for the h index variants MII and m index. Hence, these h index variants make a non-redundant contribution to the h index. 相似文献
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This paper reviews a number of studies comparing Thomson Scientific’s Web of Science (WoS) and Elsevier’s Scopus. It collates their journal coverage in an important medical subfield: oncology. It is found that all WoS-covered oncological journals (n = 126) are indexed in Scopus, but that Scopus covers many more journals (an additional n = 106). However, the latter group tends to have much lower impact factors than WoS covered journals. Among the top 25% of sources with the highest impact factors in Scopus, 94% is indexed in the WoS, and for the bottom 25% only 6%. In short, in oncology the WoS is a genuine subset of Scopus, and tends to cover the best journals from it in terms of citation impact per paper. Although Scopus covers 90% more oncological journals compared to WoS, the average Scopus-based impact factor for journals indexed by both databases is only 2.6% higher than that based on WoS data. Results reflect fundamental differences in coverage policies: the WoS based on Eugene Garfield’s concepts of covering a selective set of most frequently used (cited) journals; Scopus with broad coverage, more similar to large disciplinary literature databases. The paper also found that ‘classical’, WoS-based impact factors strongly correlate with a new, Scopus-based metric, SCImago Journal Rank (SJR), one of a series of new indicators founded on earlier work by Pinski and Narin [Pinski, G., & Narin F. (1976). Citation influence for journal aggregates of scientific publications: Theory, with application to the literature of physics. Information Processing and Management, 12, 297–312] that weight citations according to the prestige of the citing journal (Spearman’s rho = 0.93). Four lines of future research are proposed. 相似文献
4.
We investigate the effect of feature weighting on document clustering, including a novel investigation of Okapi BM25 feature
weighting. Using eight document datasets and 17 well-established clustering algorithms we show that the benefit of tf-idf weighting over tf weighting is heavily dependent on both the dataset being clustered and the algorithm used. In addition, binary weighting
is shown to be consistently inferior to both tf-idf weighting and tf weighting. We investigate clustering using both BM25 term saturation in isolation and BM25 term saturation with idf, confirming that both are superior to their non-BM25 counterparts under several common clustering quality measures. Finally,
we investigate estimation of the k1 BM25 parameter when clustering. Our results indicate that typical values of k1 from other IR tasks are not appropriate for clustering; k1 needs to be higher. 相似文献
5.
We consider text retrieval applications that assign query-specific relevance scores to documents drawn from particular collections.
Such applications represent a primary focus of the annual Text Retrieval Conference (TREC), where the participants compare
the empirical performance of different approaches. P(K), the proportion of the top K documents that are relevant, is a popular measure of retrieval effectiveness.
Participants in the TREC Very Large Corpus track have observed that when the target is a random sample from a collection,
P(K) is substantially smaller than when the target is the entire collection. Hawking and Robertson (2003) confirmed this finding
in a number of experimental settings. Hawking et al. (1999) posed as an open research question the cause of this phenomenon
and proposed five possible explanatory hypotheses. In this paper, we present a mathematical analysis that sheds some light
on these hypotheses and complements the experimental work of Hawking and Robertson (2003). We will also introduce C(L), contamination at L, the number of irrelevant documents amongst the top L relevant documents, and describe its properties.
Our analysis shows that while P(K) typically will increase with collection size, the phenomenon is not universal. That is, the asymptotic behavior of P(K) and C(L) depends on the score distributions and relative proportions of relevant and irrelevant documents in the collection.
While this article went to press, Yehuda Vardi passed away. We dedicate the paper to his memory. 相似文献
6.
Antonio Quesada 《Journal of Informetrics》2011,5(3):476-480
The Hirsch index and the Egghe index are both numbers that synthesize a researcher's output. The h-index associated with researcher r is the maximum number h such that r has h papers with at least h citations each. The g-index is the maximum number g of papers by r such that the average number of citations of the g papers is at least g. Both indices are characterized in terms of four axioms. One identifies outputs deserving index at most one. A second one establishes a strong monotonicity condition. A third one requires the index to satisfy a property of subadditivity. The last one consists of a monotonicity condition, for the h-index, and an aggregate monotonicity condition, for the g-index. 相似文献
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Robert W. P. Luk 《Information Retrieval》2008,11(6):539-561
This paper discusses various issues about the rank equivalence of Lafferty and Zhai between the log-odds ratio and the query
likelihood of probabilistic retrieval models. It highlights that Robertson’s concerns about this equivalence may arise when
multiple probability distributions are assumed to be uniformly distributed, after assuming that the marginal probability logically
follows from Kolmogorov’s probability axioms. It also clarifies that there are two types of rank equivalence relations between
probabilistic models, namely strict and weak rank equivalence. This paper focuses on the strict rank equivalence which requires
the event spaces of the participating probabilistic models to be identical. It is possible that two probabilistic models are
strict rank equivalent when they use different probability estimation methods. This paper shows that the query likelihood,
p(q|d, r), is strict rank equivalent to p(q|d) of the language model of Ponte and Croft by applying assumptions 1 and 2 of Lafferty and Zhai. In addition, some statistical
component language model may be strict rank equivalent to the log-odds ratio, and that some statistical component model using
the log-odds ratio may be strict rank equivalent to the query likelihood. Finally, we suggest adding a random variable for
the user information need to the probabilistic retrieval models for clarification when these models deal with multiple requests. 相似文献
9.
Abstract Furunori (aged paste) is a conservation material that is used for Japanese painting conservation. Furunori is a smoother and weaker adhesive than fresh paste, and it enables the surfaces to be easily peeled apart, with application of water, in a future conservation. Due to these characteristics, furunori has traditionally been used for attaching the backing paper to paintings in Japan, because it is considered that furunori causes less stress on the paintings than fresh paste. This study aims to clarify the characteristics of furunori based on chemical analysis and examination of the microorganisms involved in the early stage of furunori generation. Based on the results obtained, a polysaccharide similar to furunori was prepared. 相似文献
10.
Marcus Nevitt 《Media History》2017,23(2):218-240
This article offers detailed analysis of the patterns of book advertising in Marchamont Nedham’s government-sponsored newsbook, Mercurius Politicus. It contends that, for a brief period, Politicus was the nearest thing that the mid-seventeenth century had to a literary periodical and contests standard accounts that Politicus was only successful because government monopoly made it so. Instead I show that Politicus was instrumental in creating an image of the Commonwealth and Protectorate as a Republic of Letters; the cheap print of its small advertisements insisted that the publication of a book was an event, that London was a city of the book, and that its inhabitants might respond to the uncertainty of political revolution by eagerly imagining a future comprised of new books as yet unread. 相似文献
11.
“There’s nothing I hate more than a racist:” (Re)centering whiteness in American Horror Story: Coven
Amanda Kay LeBlanc 《Critical Studies in Media Communication》2018,35(3):273-285
This article examines race and racism in the popular cable horror-drama American Horror Story: Coven. Centered around a feud between a white witch coven and a black, voodoo group of witches, Coven overtly deals with the issue of racism, but presents racism as a phenomenon contained in the past; something that does not happen anymore. Using critical post-race theory and scholarship on colorblind racism, whiteness, as well as black feminist theory, I show that although the narrative of Coven explicitly decries racism, it simultaneously invests in colorblind racist narratives and dialogue. Whiteness is central in Coven, operating through discourse that ignores racial difference and contemporary forms of oppression and erasure. Coven uses graphic depictions of violence against black bodies, makes explicit connections between black sexuality and animals, and uses exotic and aggressive stereotypes of black women to tell its story. Thus, Coven’s narrative both condemns racism and relies on it. This article shows that the contemporaneous presentations of explicit anti-racist dialogue and racist imagery work to (re)place whiteness at the center of Coven, a TV show that purports to forward a message of equality and justice for those who are different. 相似文献
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David C. Tyler Signe Boudreau Katharine C. Potter Misty Redinbaugh 《Behavioral & Social Sciences Librarian》2013,32(4):57-87
ABSTRACT In a prior edition of this study, we examined whether the established online communication studies indexes—Communication Abstracts, ComIndex, and ComAbstracts—provided a good avenue of access to the journal literature that researchers in the field cite and whether, where the current journal literature was concerned, that avenue of access might be equal or superior to that provided by large, multisubject online indexes. In this iteration of the study, we similarly address EBSCO's new product for communication studies, Communication & Mass Media Complete. 相似文献
13.
The ability to correctly classify sentences that describe events is an important task for many natural language applications
such as Question Answering (QA) and Text Summarisation. In this paper, we treat event detection as a sentence level text classification
problem. Overall, we compare the performance of discriminative versus generative approaches to this task: namely, a Support
Vector Machine (SVM) classifier versus a Language Modeling (LM) approach. We also investigate a rule-based method that uses
handcrafted lists of ‘trigger’ terms derived from WordNet. Two datasets are used in our experiments to test each approach
on six different event types, i.e., Die, Attack, Injure, Meet, Transport and Charge-Indict. Our experimental results show that the trained SVM classifier significantly outperforms the simple rule-based system and
language modeling approach on both datasets: ACE (F1 66% vs. 45% and 38%, respectively) and IBC (F1 92% vs. 88% and 74%, respectively).
A detailed error analysis framework for the task is also provided which separates errors into different types: semantic, inference, continuous and trigger-less. 相似文献
14.
Nadine Ehlers 《传播与批判/文化研究》2013,10(4):313-334
This article examines the intersectionality of law and race to argue that law, in its broadest understanding, has played a pivotal role in the performative constitution of racial subjects. This disciplinary regulation, which has operated to “fix” an individual within a racial status under law, has augmented the production of the individual as a raced subject. An analysis of Rhinelander v. Rhinelander, however, illuminates that a defiance of racial performative dictates can render “race” hidden in plain sight. This rendering represents an escape from the regulatory mechanisms of law, posing a counter‐power that threatens to disturb hegemonic whiteness. 相似文献
15.
Christopher L. Aberson 《Communication monographs》2016,83(2):276-280
In this rejoinder, I argue that explanations made in Croucher (2015) [Further development of integrated threat theory and intergroup contact: A reply to Aberson (2015). Communication Monographs] for odd results are not theoretically relevant, represent highly unlikely outcomes inconsistent with the reporting in Croucher (2013) [Integrated threat theory and acceptance of immigrant assimilation: An analysis of Muslim immigration in Western Europe. Communication Monographs, 80, 46–62], and are likely not the result of a unique sample or target. First, I demonstrate that arguments regarding negative contact are not applicable to the present work as Croucher (2013) [Integrated threat theory and acceptance of immigrant assimilation: An analysis of Muslim immigration in Western Europe. Communication Monographs, 80, 46–62] measured positive contact. Next, I note that arguments regarding use of pairwise deletion are theoretically possible, but practically would represent extreme situations that suggest substantial issue with the dataset. I also note that Croucher (2013) [Integrated threat theory and acceptance of immigrant assimilation: An analysis of Muslim immigration in Western Europe. Communication Monographs, 80, 46–62] made no mention of the amount of missing data or approaches used to deal with missing values. Finally, I highlight that the use of an adult sample and Muslim targets is by no means unique within the integrated threat literature and that findings from studies using similar samples and targets remain at odds with Croucher (2013) [Integrated threat theory and acceptance of immigrant assimilation: An analysis of Muslim immigration in Western Europe. Communication Monographs, 80, 46–62]. 相似文献
16.
Marnie Ritchie 《传播与批判/文化研究》2013,10(2):179-197
This essay argues that Eye on Awareness?, a recent deployment of the If You See Something, Say Something? Department of Homeland Security campaign in US hotels, disciplines workers in order to organize their senses for the state, a process I term “feeling for the state,” by subtly redefining what it means to see the terrorist as what it means to feel the terrorist. I argue that feeling for the state throughout the training legitimizes expanded sovereign power and organizes affective labor to police racialized bodies and behaviors. I conclude by offering implications for readings of biopolitics that foreground affect. 相似文献
17.
《Communication methods and measures》2013,7(3):212-227
ABSTRACTWordscores is a popular computational text analysis method with numerous applications in communication research. Wordscores claims to scale documents on specified dimensions without requiring researchers to read or even understand the language of the input text. We investigate whether Wordscores delivers this claim by scaling the Euromanifestos of 117 political parties across 23 countries on 4 salient dimensions of political conflict. We assess validity by comparing the Wordscores estimates to expert surveys and other judgmental measures, and by examining the Wordscores’s estimates ability to predict party membership in the European Parliament groups. We find that the Wordscores estimates correlate poorly with expert and judgmental measures of party positions, while the latter outperform Wordscores in the predictive validity test. We conclude that Wordscores does not live up to its original claim of a “quick and easy” language blind method, and urge researchers to demonstrate the validity of the method in their domain of interest before any empirical analysis. 相似文献
18.
《Journalism Practice》2013,7(6):758-771
Does media ownership affect the editorial page? Scholars such as Tim Groseclose, Jeffrey Milyo, and Tim Groeling have offered recent empirical tests for media bias in political news coverage. This article focuses on the editorial content of newspapers to examine whether a change in publishers affects a newspaper's editorial page's support for government action on public policy questions, the attention given to the major political parties, and the tone of coverage of the parties. Our content analyses compare the Wall Street Journal's editorial page before and after Rupert Murdoch's News Corporation purchased the paper with two newspapers that did not change ownership structures over the same time period (New York Times and Washington Times). We show that Murdoch's Wall Street Journal is far less supportive of government intervention in the economy, much more negative to Democrats, and much more positive to Republicans than the paper's editorial page was under Bancroft family ownership. We also show that the Wall Street Journal's changes were unique as the New York Times and Washington Times generally did not exhibit similar changes to their own editorial pages. 相似文献
19.
Maria J. Grant 《Health information and libraries journal》2018,35(3):177-179
After the excitement of this summer's Health Libraries Group conference, it is important to maintain that sense of momentum and enthusiasm that being with like‐minded library and information workers can bring. #HLG2018 certainly presented plenty of opportunities for collaboration and the enthusiasm to put ideas into action. The launch of CILIP's Health Hub, bringing together content and resources co‐produced with CILIP members, together with additional categories specifically designed for those working in health to extend CILIP's. Professional Knowledge and Skills Base (PKSB) to that of PKSB for Health means there is every reason and resource available to help maintain your momentum and enthusiasm. 相似文献
20.
ABSTRACT Information professionals strive to understand the needs of communities in order to discover ways to connect and engage them in library resources and services. Positive word-of-mouth communication remains one of the most powerful tools used to develop mutually rewarding connections with the community. This article argues that libraries can harness the power of brand advocacy to transform their patrons into the most enthusiastic sharers of information, or informal brand advocates. Moreover, it emphasizes how libraries can carefully build and maintain mutually rewarding community connections through effective brand advocacy by utilizing the STEPPS framework – Social Currency, Triggers, Emotion, Public, Practical Value, Stories. Each principle in this framework can help an organization to effectively spread important brand messages. While the social currency principle encourages people to talk about topics that make them appear more favorable to others, triggers provide everyday cues that remind people of the library brand. Emotion focuses on appealing to feelings and the public principle calls for initiatives that advertise the brand. Finally, practical value motivates people to spread useful information and the stories principle explains that people share their experiences through memorable narratives. The article calls for adopting a holistic approach toward brand advocacy in applying the STEPPS framework in libraries. 相似文献