Roberto Ulloa

Roberto Ulloa
GESIS - Leibniz-Institute for the Social Sciences | GESIS · Department of Computational Social Science

PhD

About

33
Publications
4,696
Reads
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103
Citations
Additional affiliations
September 2015 - December 2015
Universidad Nacional Autónoma de México
Position
  • Collaborator: A Mathematical Model of the Political Organization of a Classic Maya City based on Scale-Free Networks
September 2014 - April 2015
The University of Western Ontario
Position
  • Assistant professor in Spanish 1030: Spanish for Beginners
April 2013 - July 2015
The University of Western Ontario
Position
  • Cognition on Sports Performance

Publications

Publications (33)
Preprint
Full-text available
In today's high-choice media environment, search engines play an integral role in informing individuals and societies about the latest events. The importance of search algorithms is even higher at the time of crisis, when users search for information to understand the causes and the consequences of the current situation and decide on their course o...
Article
Full-text available
Web search engines are important online information intermediaries that are frequently used and highly trusted by the public despite multiple evidence of their outputs being subjected to inaccuracies and biases. One form of such inaccuracy, which so far received little scholarly attention, is the presence of conspiratorial information, namely pages...
Article
Full-text available
Implicit and explicit gender biases in media representations of individuals have long existed. Women are less likely to be represented in gender-neutral media content (representation bias), and their face-to-body ratio in images is often lower (face-ism bias). In this article, we look at representativeness and face-ism in search engine image result...
Preprint
Full-text available
Online platforms have transformed the ways in which individual access and interact with news. For example, individuals put a high degree of trust in search engines. We use web-tracked behavioral data across a 2-month period and analyze three competing factors, two algorithmic (ranking and representativeness) and one psychological (familiarity), tha...
Article
Full-text available
Algorithm audits have increased in recent years due to a growing need to independently assess the performance of automatically curated services that process, filter and rank the large and dynamic amount of information available on the Internet. Among several methodologies to perform such audits, virtual agents stand out because they offer the abili...
Article
Full-text available
Search engines serve as information gatekeepers on a multitude of topics that are prone to gender, ethnicity, and race misrepresentations. In this paper, we specifically look at the image search representation of migrant population groups that are often subjected to discrimination and biased representation in mainstream media, increasingly so with...
Research
Full-text available
This whitepaper addresses the prospect of creating a digital archive for the memorialization of mass atrocities (abbreviated herein as DAMMA). It is based on the proceedings of a virtual workshop held in October 2021 that addressed questions regarding the scope, form, usages, and development of such an archive.
Article
Full-text available
Battery electric vehicles generate a significant share of their greenhouse gas emissions during production and later, when in use, through the energy used for charging. A shift in charging behavior could substantially reduce emissions if aligned with the fluctuating availability of renewable energy. Financial incentives and environmental appeals ha...
Article
Full-text available
With this work, we present a publicly available dataset of the history of all the references (more than 55 million) ever used in the English Wikipedia until June 2019. We have applied a new method for identifying and monitoring references in Wikipedia, so that for each reference we can provide data about associated actions: creation, modifications,...
Article
Full-text available
Purpose This study investigates perceptions of the use of online tracking, a passive data collection method relying on the automated recording of participant actions on desktop and mobile devices, for studying information behavior. It scrutinizes folk theories of tracking, the concerns tracking raises among the potential participants and design mec...
Preprint
Full-text available
Web search engines are important online information intermediaries that are frequently used and highly trusted by the public despite multiple evidence of their outputs being subjected to inaccuracies and biases. One form of such inaccuracy, which so far received little scholarly attention, is the presence of conspiratorial information, namely pages...
Article
Full-text available
By filtering and ranking information, search engines shape how individuals perceive both the present and past events. However, these information curation mechanisms are prone to malperformance that can misinform their users. In this article, we examine how search malperformance can influence representation of traumatic past by investigating image s...
Preprint
Full-text available
Web search engines influence perception of social reality by filtering and ranking information. However, their outputs are often subjected to bias that can lead to skewed representation of subjects such as professional occupations or gender. In our paper, we use a mixed-method approach to investigate presence of race and gender bias in representati...
Preprint
Full-text available
Algorithm audits have increased in recent years due to a growing need to independently assess the performance of automatically curated services that process, filter and rank the large and dynamic amount of information available on the internet. Among several methodologies to perform such audits, virtual agents stand out because they offer the possi...
Preprint
Full-text available
We audit the presence of domain-level source diversity bias in video search results. Using a virtual agent-based approach, we compare outputs of four Western and one non-Western search engines for English and Russian queries. Our findings highlight that source diversity varies substantially depending on the language with English queries returning m...
Chapter
Full-text available
Web search engines influence perception of social reality by filtering and ranking information. However, their outputs are often subjected to bias that can lead to skewed representation of subjects such as professional occupations or gender. In our paper, we use a mixed-method approach to investigate presence of race and gender bias in representati...
Preprint
Full-text available
We examine how six search engines filter and rank information in relation to the queries on the U.S. 2020 presidential primary elections under the default - that is nonpersonalized - conditions. For that, we utilize an algorithmic auditing methodology that uses virtual agents to conduct large-scale analysis of algorithmic information curation in a...
Article
Full-text available
We examine how six search engines filter and rank information in relation to the queries on the U.S. 2020 presidential primary elections under the default—that is nonpersonalized—conditions. For that, we utilize an algorithmic auditing methodology that uses virtual agents to conduct large-scale analysis of algorithmic information curation in a cont...
Conference Paper
Full-text available
We audit the presence of domain-level source diversity bias in video search results. Using a virtual agent-based approach, we compare outputs of four Western and one non-Western search engines for English and Russian queries. Our findings highlight that source diversity varies substantially depending on the language with English queries returning m...
Preprint
Full-text available
With this work, we present a publicly available dataset of the history of all the references (more than 55 million) ever used in the English Wikipedia until June 2019. We have applied a new method for identifying and monitoring references in Wikipedia, so that for each reference we can provide data about associated actions: creation, modifications,...
Article
Full-text available
Access to accurate and up-to-date information is essential for individual and collective decision making, especially at times of emergency. On February 26, 2020, two weeks before the World Health Organization (WHO) officially declared the COVID-19’s emergency a “pandemic,” we systematically collected and analyzed search results for the term “corona...
Preprint
Resilience and vulnerability of societies to large-scale events such as wars, climate catastrophes, immigration waves, and institutional collapses is not well-understood. Some societies prove more resilient, while others collapse. Diversity has been proposed in the literature as a potential cause of resilience in areas such as ecology, computer sci...
Article
The purpose of this article is to illustrate data transformation in a mixed methods research phenomenological study, investigating how athletes use concrete and abstract spontaneous imagery in and around competition. To achieve this, we combined the application of co-occurring codes and numerical transformation in a novel way. A thematic analysis o...
Article
Full-text available
CulSim is an agent-based computer simulation software that allows further exploration of influential and recent models of emergence of cultural groups grounded in sociological theories. CulSim provides a collection of tools to analyze resilience of cultural diversity when events affect agents, institutions or global parameters of the simulations; u...
Conference Paper
Full-text available
Cooperation in scale-free networks has proven to be very robust against removal of randomly selected nodes (error) but highly sensitive to removal of the most connected nodes (attack). In this paper we analyze two comparable types of node removal in which the removal selection is based on tournaments where the fittest (raids) or the least fit (batt...
Article
Full-text available
In a connected world where people influence each other, what can cause a globalized monoculture, and which measures help to preserve the coexistence of cultures? Previous research has shown that factors such as homophily, population size, geography, mass media, and type of social influence play important roles. In the present paper, we investigate...
Conference Paper
Full-text available
The study of external pages (pages that links a site) is important since search engines use them to rank their results. Therefore, it is useful to have a “snapshop” of the content of the external pages to understand the surroundings of a particular site in the extense topic dimensionality of Internet. To achieve this, a graph, in which the external...
Technical Report
Full-text available
The recognition of painting styles is a very complex task that has been left to human experts. The importance of preserving this kind of cultural inheritance has been recognized by the researchers as a task that can be assisted by computers since there has been a significant develops in the image processing area. In this work, I present an Adaboost...
Conference Paper
Full-text available
Modelado de oponentes en paralelo con conocimiento del dominio: búsqueda directa de estrategias en sistemas multiagentes Resumen. Se presenta un sistema de inferencia de estrategias en paralelo para un juego de múltiples agentes. Uno de los participantes del juego "adivina" la estrategia del resto distribuyendo el proceso de inferencia en una plata...
Conference Paper
Full-text available
Se presenta una herramienta de simulación para la investigación de aspectos de seguridad en sistemas de agentes. La herramienta implementa el juego “Los Hombres Lobo de Castro Negro”. La complejidad de este juego puede ser incrementada o disminuida con relativa facilidad introduciendo nuevos tipos de personajes. Cada personaje tiene reglas de inter...

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