1,720,964 research outputs found
Towards Data-Driven Agent-Based Simulation: A Case Study of West Asian Urban Dynamics
No full textThis extended abstract discusses the challenges of obtaining
data for agent-based simulation in one case. Our motivation is to explore
the e↵ects of significant migrations upon urban dynamics. To date, we
have produced a theoretically-grounded spatial agent-based model, and
validated it with data in urban contexts without migration. Now, in
contexts with migration, upon moving from an abstracted model to a
data-grounded model, we encounter a number of challenges in extending
and validating the model. The majority of these challenges concern data
Agent-based simulation of west asian urban dynamics: impact of refugees
Full text linkRapid international migration of significant populations generates profound implications for countries in West Asia, Europe, and other regions. The motivation of this work is to develop an agent-based model (ABM) to capture the existence of such migrant and refugee flows, and to explore the effects of these flows on urban dynamics. Advances in agent-based modelling have led to theoretically-grounded spatial agent models of urban dynamics, capturing the dynamics of population, property prices, and regeneration. In this article we leverage such an extant agent-based model founded on the rent-gap theory, as a lens to study the effect of sizeable refugee migration upon a capital city in West Asia. In order to calibrate and validate the simulation model we construct indices for housing prices and other factors. Results from the model, implemented in NetLogo, show the impact of migration shock on the housing market, and identify the relative efficacy of housing intervention policies. Our work progresses towards a tool for policy makers asking what-if questions about the urban environment in the context of migration
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
Urbanism and Geographic Crises: A Micro-Simulation Lens on Beirut
Full text linkAt a geographical and strategic confluence, the ancient city of Beirut, Lebanon, has witnessed crises from natural and human causes over the centuries. The modern urban and peri-urban development is a result of neo-classical economics, laissez-faire regulations, and complex socio-political structures. This article considers the contemporary housing situation and asks about its resilience to crises. The methodological approach is speculative simulation. We capture the urban status quo through agent-based simulation, and simulate a range of independent shocks. Although the goal of the article is exploratory and not historical replay, the shocks considered are historical exemplars, such as the explosion on August 4th, 2020. Looking across peri-urban Beirut, we measure qualitative effects on housing economics and dynamics. The research question thus addressed is to determine the optimal amount of capital needed for regeneration without triggering a price increase in the housing market. The contribution of the article is a data-and-modelling approach to humane questions of interest to urban scholars. The simulation model is available open source to provoke further enquiry.Algorithmic
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
Capital Investment as Real Options: A Note on Dixit-Pindyck Model.
Full text linkAbstract
This paper applies Contingent Claims model a la Dixit and Pindyck (1994), on bank investment. Banks are indifferent between investing their assets on their own and extending loans to investors. The critical decision faced by the banker is the timing of the investment decision and its uncertainty. When banks make an irreversible investment decision they exercise the option to invest and give up the opportunity of waiting for new information to arrive. This lost option value is incorporated in the investment cost. Therefore, the value of the project must exceed the investment cost by the value of keeping the investment option alive. Using a third-moment mean-reversion process of the investment’s volatility, the model shows that a higher mean-reversion parameter reduces both the value of the option to invest and the critical value at which the project deems feasible
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