1,720,961 research outputs found
Network partitioning algorithms for electricity consumer clustering
No full textThis electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.Thesis: S.M. in Technology and Policy, Massachusetts Institute of Technology, School of Engineering, Institute for Data, Systems, and Society, Technology and Policy Program, 2018Thesis: S.M., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2018Cataloged from student-submitted PDF version of thesis.Includes bibliographical references (pages 97-103).In many developing countries, access to electricity remains a significant challenge. Electrification planners in these countries often have to make important decisions on the mode of electrification and the planning of electrical networks for those without access, while under resource constraints. To facilitate the achievement of universal energy access, the Reference Electrification Model (REM), a computational model capable of providing techno-economic analysis and data-driven decision support for these planning efforts, has been developed. Primary among REM's capabilities is the recommendation of the least-cost mode of electrification - i.e by electric grid extension or off-grid systems - for non-electrified consumers in a region under analysis, while considering technical, economic and environmental constraints.This is achieved by the identification of consumer clusters (either as clusters of off-grid microgrids, stand-alone systems or grid-extension projects) using underlying clustering methods in the model. This thesis focuses on the development and implementation of partitioning algorithms to achieve this purpose. Building on previously implemented efforts on the clustering and recommendation capabilities of REM, this work presents the development, analysis and performance evaluation of alternative approaches to the consumer clustering process, in comparison with REM's previously incorporated clustering methodology. Results show that the alternative methodology proposed can compare favorably with the hitherto implemented method in REM. Consequently, the integration of the pro- posed network partitioning procedures within REM, as well as some potential future research directions, is discussed.Finally, this thesis concludes with a discourse on the social and regulatory aspects of energy access and electricity planning in developing countries, providing some perspectives on the development policies and business models that complement the technological contributions of this work.by Olamide Oladeji.S.M. in Technology and PolicyS.M.S.M.inTechnologyandPolicy Massachusetts Institute of Technology, School of Engineering, Institute for Data, Systems, and Society, Technology and Policy ProgramS.M. Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Scienc
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
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Stochastic modeling of channel meanders and resultant point bars
Full text linkThe evolution of river meanders over time greatly determines the distribution of point bars along alluvial streams. These point bars are curvilinear deposits and form potential reservoirs for hydrocarbons. As part of reservoir modeling, it is necessary to reconstruct alluvial stream meanders based on which point bars may have been deposited. This will allow better modeling of connectivity patterns that have significant impact on fluid flow and transport properties within hydrocarbon reservoirs. Multiple point (mp) statistics can be applied to model connectivity patterns in a spatial domain. However, controlling the migration of channels so as to model the location of point bars consistent with the conditioning information observed in the field is difficult within the mp statistics based schemes. In contrast, we generate connected centerlines for meanders, such that they pass through given sets of channel locations deduced from well logs and simultaneously, the meanders are curved so as to yield point bar at the correct locations. These centerlines are stochastically generated, geologically realistic and made to capture applicable geomorphological observations. Based on the generated meander centerlines, several realizations of 3D geologic models are developed and further used to model fluid flow. The stochastic modeling methodology is applied to a real field data set for the Cranfield field in Mississippi. In this reservoir, there are several channel meanders and consequently, the stratigraphic layers are modeled independently. The results demonstrate that the implemented algorithm is a better approach to modeling connectivity patterns in alluvial systems where flow pattern identification is often challenging.Petroleum and Geosystems Engineerin
Information Extraction: An application to the domain of hyper-local financial data on developing countries
Full text linkDespite the need for financial data on company activities in developing
countries for development research and economic analysis, such data does not
exist. In this project, we develop and evaluate two Natural Language Processing
(NLP) based techniques to address this issue. First, we curate a custom dataset
specific to the domain of financial text data on developing countries and
explore multiple approaches for information extraction. We then explore a
text-to-text approach with the transformer-based T5 model with the goal of
undertaking simultaneous NER and relation extraction. We find that this model
is able to learn the custom text structure output data corresponding to the
entities and their relations, resulting in an accuracy of 92.44\%, a precision
of 68.25\% and a recall of 54.20\% from our best T5 model on the combined task.
Secondly, we explore an approach with sequential NER and relation extration.
For the NER, we run pre-trained and fine-tuned models using SpaCy, and we
develop a custom relation extraction model using SpaCy's Dependency Parser
output and some heuristics to determine entity relationships \cite{spacy}. We
obtain an accuracy of 84.72\%, a precision of 6.06\% and a recall of 5.57\% on
this sequential task
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
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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