1,720,964 research outputs found
Three Essays in Agent-Based Macroeconomics
Full text linkQuesta tesi cerca di contribuire alla crescente letteratura sulla Macroeconomia basata sugli agenti lungo tre linee di ricerca organizzate in tre capitoli distinti: (i) un'applicazione ABM a uno specifico problema macroeconomico; (ii) un contributo metodologico; (iii) una revisione critica sulle sfide aperte che devono ancora essere affrontate dai modellisti ABM;This dissertation seeks to contribute to the growing literature on Agent-Based Macroeconomics along three lines of research organised in three distinct chapters: (i) an ABM application to a specific macroeconomic problem; (ii) a methodological contribution; (iii) a critical review about open challenges still to be faced by ABM modellers;
Although the three chapters can be read independently from each other, I would argue that they show a certain degree of complementarity. Indeed, some insights and findings presented in chapter 2 and 3 support at least partially the modelling strategy implemented in chapter 1, whereas others can be used in the future to refine and improve the model presented in chapter 1.
The organisation of the chapters may seem unusual, in particular the choice to place the literature review at the end of the dissertation. This reflects the trajectory of my research: admittedly, when I started my PhD journey I was not fully aware of many critical issues affecting ABMs, however as my research advanced unresolved challenges stood in my way, some of which I decided to directly address in this dissertation, this is the case of chapter 2, others I decided to critically discuss, which is the case of chapter 3.
In chapter 1 I propose a macroeconomic model suitable for studying technological innovations and structural change, moreover I provide an application of such model which elucidates a plausible and empirically sound mechanism leading from automation to job polarization. The model proposed in this chapter extends and complements models already well established in the literature, in particular it introduces heterogenous consumption goods, the possibility to model a non vertically integrated multi-sectors economy, and a novel production system in which different types of labor must be combined in the production process.
The model, in its general version, is intended to be flexible enough to accommodate for future extensions and therefore to address a variety of research questions dealing with technological change, structural change, and labor market outcomes in terms of: aggregate employment, labor flows across sectors and skill specific reactions to technological shocks.
In chapter 1 I also provide an application of the model to study how automation can lead to job polarization. The modelling strategy has been designed to be as close as possible to available empirical evidence on robots, sectorial workers skill distribution, and consumer preferences over differentiated goods. This allows to provide empirical grounding to some interesting and sometimes counterintuitive results. In particular, the model helps to understand a possible mechanism leading from automation to job polarization. As we will see, a sector specific labor-saving and skill-biased technological shock, which per se should depress the employment share of low skilled workers and increase the employment share of high skilled workers, can actually set in motion a chain of causal events leading to structural change at first and eventually to job polarization. In the chapter such mechanism will be explained in details, moreover it will be justified in light of available empirical evidence and its robustness proved by means of extensive sensitivity analysis.
The second chapter is a methodological contribution, which tries to understand how to model expectations in ABMs. To begin with, the chapter tries to clarify which type of rationality is best suited in the ABM framework, maintaining that: (i) rational expectations a lá Muth are neither applicable, nor needed in the ABM framework; (ii) what is sufficient to achieve in ABMs is collective rationality, which simply implies that the aggregate mean forecasting error is on average zero, i.e. the economy as a whole is not systematically mistaken in making predictions.
Therefore, under the assumption that collective rationality is sufficient in the ABM frame-work, the chapter studies the performances of different expectations formation mechanism within two agent based models. Moreover, I introduce a learning algorithm which combined to "static" expectations allows to update the otherwise fixed parameters contained in the expectation rules. Thus, the goal is to study whether it is possible to obtain aggregate unbiased expectations in an ABM framework. Since typically a macro ABM does not have a closed form solution, I rely on extensive computer simulations in order to assess the performances of different expectation formation mechanisms in different contexts. I do so in two macro environments: (i) a very simple and stylised model in which agents try to forecast a stationary variable and (ii) a full fledged macro ABM in which agents try to forecast a trended variable. In case (i) I designed a simple model in which a central bank set the interest rate and households try to forecast the one-step ahed inflation rate. In this context I will assess the performances of different expectation formation mechanisms across policy regimes and policy shocks. In case (ii) I will employ the model put forward in Caiani et al. (2016) augmented by technological innovation as in Caiani et al. (2019). This is a full fledged macro ABM which I use as a laboratory to assess different expectation formation mechanisms applied to firms trying to forecast future sales. The expectation rules employed in the following exercise are: naive expectations, where the expected value of a variable equals its past realisation, adaptive expectations, trend following, and social learning in the form of a very simple genetic algorithm. Moreover, I also employ hybrid expectations in which adaptive expectations and trend following are combined with learning.
The last chapter discusses some of the main challenges for ABMs, in particular it deals with how to bridge models to real data and how to address the Lucas critique in ABMs. Overall, it is intended as a review of ongoing research on these issues, however I also sug- gest some possible ways to deal with the specific problems surveyed. The chapter concludes with a preliminary meta-analysis trying to assess the state of the art of currently widespread modelling practises, with respect to the challenges laid down in the chapter
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
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
Author Under Sail The Imagination of Jack London, 1893-1902
No full textIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Intro -- Title Page -- Copyright Page -- Dedication -- Contents -- Acknowledgments -- Introduction -- 1. Spirit Truth -- 2. From Absorption to Theatricality and Back Again -- 3. "I Will Build a New Present" -- 4. Sons as Authors -- 5. Fathers as Publishers -- 6. The Daughter as Author -- 7. Lovers as Authors -- 8. At Sea with the Family -- 9. Yellow News, Yellow Stories -- 10. The Return Home -- Notes -- Bibliography -- Index -- About Jay WilliamsIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Description based on publisher supplied metadata and other sources.Electronic reproduction. Ann Arbor, Michigan : ProQuest Ebook Central, YYYY. Available via World Wide Web. Access may be limited to ProQuest Ebook Central affiliated libraries
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