1,720,987 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
Recommended from our members
Tsunami and hurricane wave loads on bridge superstructures
Full text linkThis dissertation examines tsunami and hurricane wave loads on bridge superstructures. Tsunamis have caused significant damage to coastal communities in recent years. For example, the 2011 Great East Japan Earthquake and resulting Tohoku Tsunami destroyed infrastructure along the east coast of Japan including bridge superstructures. Recent hurricanes have also caused extensive damage to coastal bridges in the southern US coastal areas along the Gulf of Mexico. Several coastal highway bridges were completely destroyed and many more experienced substantial damage during Hurricane Katrina in 2005.
The first part of this study examines the tsunami loads on five California and three Oregon coastal bridges. Finite element (FE) models are used to simulate the tsunami loads on these bridges. The FE model includes water and air as a two-phase gravity flow separated by a water free-surface, and a bridge superstructure modeled as a rigid body. The quantities of interest include horizontal and vertical forces and overturning moment. Simulations and analyses are conducted for two tsunami load stages: (1). initial impact and overtopping, and (2). full inundation. The first stage starts from the time when the tsunami water free-surface elevation reaches the low chord of the bridge superstructure, and the water free-surface rises and reaches the top of the bridge barrier where it overtops the bridge and flows on the bridge deck, and until the bridge is totally inundated. The second stage begins when the bridge first becomes fully inundated (i.e. end of first stage) and until all the important events: (a) the maximum tsunami water velocity, (b) the maximum tsunami momentum flux, and (c) the maximum tsunami mass flux, have occurred. In the first part of stage 1, initial impact and overtopping leads to a combination of lateral (horizontal) and uplift (upward vertical) forces. The maximum uplift force during this stage is found to occur when the tsunami water free-surface elevation reaches the top of the bridge barrier right before the water overtopping the bridge and starting to flow onto the bridge deck. The maximum tsunami horizontal and downward vertical loads are found to occur approximately simultaneously when the tsunami flow reaches the landward side of the bridge cross-section and overtops the barrier. It is observed that the time interval representing the initial impact of the tsunami on the bridge superstructure leads to the maximum horizontal force, downward vertical force, and overturning moment. The overall maximum uplift force is found to be in tsunami scenarios where the bridge superstructure is totally inundated, i.e. in stage 2, if total inundation actually occurs. A design procedure is proposed to compute the maximum horizontal and vertical forces on bridge superstructures based on the simulation results. Good agreement between numerical predictions and formula estimations of the tsunami forces is observed.
The second part of this study examines the influence of trapped air on resultant wave forces under different wave conditions for a variety of bridge geometries. Both two and three-dimensional model numerical simulations are performed using a validated finite element model in which two different approaches are used to model the air. The first model is a two-phase simulation containing water and air with associated densities and equation of states while in the second model a single-phase (water only) simulation is conducted. The difference in resulting wave forces is totally attributed to presence of the trapped air. Wave uplift forces are found to be 57%-88% smaller for a wide range of wave periods when the effect of the trapped air is neglected. Moreover, the effectiveness of the presence of air vents in reducing the air pressure between girders and the resulting wave forces is evaluated. Numerical results indicate that the uplift wave forces acting on the bridge superstructures can be reduced by about 56% on the average using air vents
Terrain modelling and classification using full-waveform LiDAR
No full text© 2016 Dr. Mohsen AzadbakhtFull-waveform LiDAR systems capture the complete backscattered signal from the interaction of the laser beam with target(s) located within the laser footprint. The resulting data have advantages over discrete return LiDAR, including higher accuracy of the range measurements and the possibility of retrieving additional returns from weak and overlapping pulses. In addition, radiometric characteristics of targets, e.g. target cross-section, can also be retrieved from the waveforms. These capabilities make waveform LiDAR systems advantageous for a broad range of applications. However, waveform restoration and removal of the effect of the emitted system pulse from the returned waveform are critical for precise range measurement, 3D reconstruction and target cross-section extraction.
In this thesis, a reliable regularization approach, necessary to deconvolve the returned LiDAR waveform and restore the target cross-section, is presented based on sparsity-constrained regularization. The optimal regularization parameter is determined based on the L-curve and generalized cross validation (GCV) methods, with the former providing higher consistency in varied conditions. A new approach for the estimation of system waveform is presented which is useful when the system waveform is not available in the LiDAR data. The system waveform is approximated based on blind deconvolution over the received LiDAR waveforms of standard flat targets (e.g., asphalt). The reliability of blind deconvolution is compared with existing approaches, with respect to oscillation of the temporal cross-section and the accumulated cross-section value for each pulse. Quantitative evaluation and visual assessment of results are presented in comparison with other prominent deconvolution approaches. The superior performance demonstrates the potential of the proposed regularization approach to remove the effect of system waveform in the returned LiDAR signal and reconstruct the target cross-section, therefore improving the accuracy of both range measurements and geophysical attribute retrieval. This also highlights the feasibility and consistency of the presented approach to the processing of a variety of LiDAR data acquired under different system configurations.
Even though full-waveform LiDAR was mainly developed for vegetation studies, efforts have recently been made for utilization of such data in land cover classification of urban areas. In this thesis, new features in small footprint LiDAR data are introduced and their relevance in the separation of different targets in an urban scene is investigated. A wide range of classes, including trees, medium vegetation, low vegetation (grass), water bodies, pitched roofs, flat roofs, asphalt, vehicles, power lines, walls (fences) and concrete are considered. Since the similarity between some classes is quite large in terms of geometric features, it is nearly impossible to separate these classes without including waveform features. In order to tackle the challenge of distinguishing geometrically similar classes and enhancing the separability of other targets, a new set of features based on deconvolved waveforms is introduced. The positive effect of the proposed set of features on classification accuracy in individual classes is shown via utilization of state-of-the-art classifiers. Due to the fact that targets in urban environments are of different size, shape and abundance, the possibility of recording a similar number of samples from different objects is low. This causes the problem of a skewed distribution of samples. Therefore, apart from direct utilization of the classifiers with different number of trees, combinations of the classifiers with different sampling techniques in data mining are proposed in order to address the problem of an imbalanced dataset
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
- …
