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1,171 results on '"Perez, Sergio"'

169. On the Use of Latency Graphs for the Construction of Tor Circuits

Author

Castillo-Perez, Sergio and Garcia-Alfaro, Joaquin

Subjects
Computer Science - Cryptography and Security
Abstract

The use of anonymity-based infrastructures and anonymisers is a plausible solution to mitigate privacy problems on the Internet. Tor (short for The onion router) is a popular low-latency anonymity system that can be installed as an end-user application on a wide range of operating systems to redirect the traffic through a series of anonymising proxy circuits. The construction of these circuits determines both the latency and the anonymity degree of the Tor anonymity system. While some circuit construction strategies lead to delays which are tolerated for activities like Web browsing, they can make the system vulnerable to linking attacks. We evaluate in this paper three classical strategies for the construction of Tor circuits, with respect to their de-anonymisation risk and latency performance. We then develop a new circuit selection algorithm that considerably reduces the success probability of linking attacks while keeping a good degree of performance. We finally conduct experiments on a real-world Tor deployment over PlanetLab. Our experimental results confirm the validity of our strategy and its performance increase for Web browsing., Comment: 34

Published
2012

170. Vacancy-Dependent Bulk and Surface Retention of Hydrogen Isotopes in Tungsten—A Molecular Dynamics Study

Author

Towell, Sophie, Lavrentiev, Mikhail Yu., and Lozano-Perez, Sergio

Abstract

Tungsten, given its high heat and neutron resistance, is often the material of choice for plasma-facing components in nuclear fusion reactors. However, understanding and predicting the behavior of hydrogen isotopes (deuterium and tritium) within tungsten’s lattice poses a significant challenge. The retention and diffusion of these isotopes, which are influenced by microstructural defects such as vacancies, can significantly impact the performance and safety of fusion devices. This article employs the Large-scale Atomic/Molecular Massively Parallel Simulator (LAMMPS) simulation package to analyze the behavior of hydrogen isotopes in tungsten lattices with varying vacancy densities. Simple relationships between penetration depth and energy and mass of hydrogen isotope, as well as between reflection/penetration ratio, are found. The effect of vacancies on isotope diffusion and retention in the material and the role of temperature in this process are investigated.

Published
2024
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171. Cracking and Void Formation in Bulk W Components Manufactured for JET ITER-Like Wall

Author

Kerr, Robert, Lozano-Perez, Sergio, Armstrong, David E. J., Meier, Martin S., Moody, Michael P., Zayachuk, Yevhen, and Widdowson, Anna

Abstract

When manufacturing W for fusion applications, it is crucial to consider microstructural features, such as grain shape and size, dislocation densities, distribution of defects, and impurities. These factors have a significant impact on a component’s lifetime in the fusion environment. This work provides valuable insights into the potential failure mechanisms that impact bulk W components. A bulk W lamella, which was manufactured for the JET divertor as part of the ITER-like wall (ILW) campaigns, was studied. A crack network had formed on the plasma-facing surface of the sample due to electrical discharge machining (EDM). The cracks predominantly propagated around larger grains due to grain misorientation and impurities. Notably, P and Fe were observed via atom probe tomography (APT), which appears to promote the diffusion of O. The results suggest that the initiation of crack propagation is linked to the nucleation of voids which exhibit behavior akin to KSiAl-doped W wires, involving diffusion-driven processes. O signal found inside some of the voids, confirmed by analytical transmission electron microscopy (TEM), suggests W oxide had formed on the internal surface, supporting the theory of oxidation-assisted void formation. It is, therefore, extremely important to consider the distribution of impurities and preexisting surface damage in W plasma-facing components (PFCs) before they are placed in the vessel.

Published
2024
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172. Highlights from the SOAP project survey. What Scientists Think about Open Access Publishing

Author

Dallmeier-Tiessen, Suenje, Darby, Robert, Goerner, Bettina, Hyppoelae, Jenni, Igo-Kemenes, Peter, Kahn, Deborah, Lambert, Simon, Lengenfelder, Anja, Leonard, Chris, Mele, Salvatore, Nowicka, Malgorzata, Polydoratou, Panayiota, Ross, David, Ruiz-Perez, Sergio, Schimmer, Ralf, Swaisland, Mark, and van der Stelt, Wim

Subjects
Computer Science - Digital Libraries
Abstract

The SOAP (Study of Open Access Publishing) project has run a large-scale survey of the attitudes of researchers on, and the experiences with, open access publishing. Around forty thousands answers were collected across disciplines and around the world, showing an overwhelming support for the idea of open access, while highlighting funding and (perceived) quality as the main barriers to publishing in open access journals. This article serves as an introduction to the survey and presents this and other highlights from a preliminary analysis of the survey responses. To allow a maximal re-use of the information collected by this survey, the data are hereby released under a CC0 waiver, so to allow libraries, publishers, funding agencies and academics to further analyse risks and opportunities, drivers and barriers, in the transition to open access publishing., Comment: Data manual available at http://bit.ly/gI8nct Compressed CSV data file available at http://bit.ly/gSmm71 Alternative data formats: CSV http://bit.ly/ejuvKO XLS http://bit.ly/e6gE7o XLSX http://bit.ly/gTjyvy

Published
2011

173. First results of the SOAP project. Open access publishing in 2010

Author

Dallmeier-Tiessen, Suenje, Darby, Robert, Goerner, Bettina, Hyppoelae, Jenni, Igo-Kemenes, Peter, Kahn, Deborah, Lambert, Simon, Lengenfelder, Anja, Leonard, Chris, Mele, Salvatore, Polydoratou, Panayiota, Ross, David, Ruiz-Perez, Sergio, Schimmer, Ralf, Swaisland, Mark, and van der Stelt, Wim

Subjects
Computer Science - Digital Libraries
Abstract

The SOAP (Study of Open Access Publishing) project has compiled data on the present offer for open access publishing in online peer-reviewed journals. Starting from the Directory of Open Access Journals, several sources of data are considered, including inspection of journal web site and direct inquiries within the publishing industry. Several results are derived and discussed, together with their correlations: the number of open access journals and articles; their subject area; the starting date of open access journals; the size and business models of open access publishers; the licensing models; the presence of an impact factor; the uptake of hybrid open access., Comment: Submitted to PLoS ONE

Published
2010

175. Technological Change, Tasks and Class Inequality in Europe.

Author

Gil-Hernández, Carlos J, Vidal, Guillem, and Torrejón Perez, Sergio

Subjects
TECHNOLOGICAL innovations, SOCIAL status, WEALTH inequality, INCOME inequality, DIGITAL technology, SOCIAL stratification, GENDER inequality, SUPINE position
Abstract

Neo-Weberian occupational class schemas, rooted in industrial-age employment relations, are a standard socio-economic position measure in social stratification. Previous research highlighted Erikson-Goldthorpe-Portocarero (EGP)-based schemas' difficulties in keeping up with changing labour markets, but few tested alternative explanations. This article explores how job tasks linked to technological change and rising economic inequality might confound the links between employment relations, classes, and life chances. Using the European Working Conditions Survey covering the European Union (EU)-27 countries, this article analyses over time and by gender: 1) the task distribution between social classes; and 2) whether tasks predict class membership and life chances. Decomposition analyses suggest that tasks explain class membership and wage inequality better than theorised employment relations. However, intellectual/routine tasks and digital tools driving income inequality are well-stratified by occupational classes. Therefore, this article does not argue for a class (schema) revolution but for fine-tuning the old instrument to portray market inequalities in the digital age. [ABSTRACT FROM AUTHOR]

Published
2024
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181. A Groundbreaking Technology in Virtual Rehabilitation to Improve Falls in Older People

Author

Da Silva, Marlene Goncalves, Albiol-Pérez, Sergio, Lombano, Javier López, Salas, Sonsoles Valdivia, Cano, Sandra, Gutierrez, Erika Giselle, Jacho-Guanoluisa, Nancy, Collazos, Cesar A., Kacprzyk, Janusz, Series Editor, Pal, Nikhil R., Advisory Editor, Bello Perez, Rafael, Advisory Editor, Corchado, Emilio S., Advisory Editor, Hagras, Hani, Advisory Editor, Kóczy, László T., Advisory Editor, Kreinovich, Vladik, Advisory Editor, Lin, Chin-Teng, Advisory Editor, Lu, Jie, Advisory Editor, Melin, Patricia, Advisory Editor, Nedjah, Nadia, Advisory Editor, Nguyen, Ngoc Thanh, Advisory Editor, Wang, Jun, Advisory Editor, Rocha, Álvaro, editor, Adeli, Hojjat, editor, Reis, Luís Paulo, editor, and Costanzo, Sandra, editor

Published
2018
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182. A Novel Approach in Virtual Rehabilitation for Children with Cerebral Palsy: Evaluation of an Emotion Detection System

Author

Albiol-Pérez, Sergio, Cano, Sandra, Da Silva, Marlene Goncalves, Gutierrez, Erika Giselle, Collazos, Cesar A., Lombano, Javier López, Estellés, Elena, Ruiz, Mónica Alberich, Kacprzyk, Janusz, Series Editor, Pal, Nikhil R., Advisory Editor, Bello Perez, Rafael, Advisory Editor, Corchado, Emilio S., Advisory Editor, Hagras, Hani, Advisory Editor, Kóczy, László T., Advisory Editor, Kreinovich, Vladik, Advisory Editor, Lin, Chin-Teng, Advisory Editor, Lu, Jie, Advisory Editor, Melin, Patricia, Advisory Editor, Nedjah, Nadia, Advisory Editor, Nguyen, Ngoc Thanh, Advisory Editor, Wang, Jun, Advisory Editor, Rocha, Álvaro, editor, Adeli, Hojjat, editor, Reis, Luís Paulo, editor, and Costanzo, Sandra, editor

Published
2018
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183. Erlang Code Evolution Control

Author

Insa, David, Pérez, Sergio, Silva, Josep, Tamarit, Salvador, Hutchison, David, Series Editor, Kanade, Takeo, Series Editor, Kittler, Josef, Series Editor, Kleinberg, Jon M., Series Editor, Mattern, Friedemann, Series Editor, Mitchell, John C., Series Editor, Naor, Moni, Series Editor, Pandu Rangan, C., Series Editor, Steffen, Bernhard, Series Editor, Terzopoulos, Demetri, Series Editor, Tygar, Doug, Series Editor, Weikum, Gerhard, Series Editor, Fioravanti, Fabio, editor, and Gallagher, John P., editor

Published
2018
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184. Thermal Prediction for Immersion Cooling Data Centers Based on Recurrent Neural Networks

Author

Pérez, Jaime, Pérez, Sergio, Moya, José M., Arroba, Patricia, Hutchison, David, Series Editor, Kanade, Takeo, Series Editor, Kittler, Josef, Series Editor, Kleinberg, Jon M., Series Editor, Mattern, Friedemann, Series Editor, Mitchell, John C., Series Editor, Naor, Moni, Series Editor, Pandu Rangan, C., Series Editor, Steffen, Bernhard, Series Editor, Terzopoulos, Demetri, Series Editor, Tygar, Doug, Series Editor, Weikum, Gerhard, Series Editor, Yin, Hujun, editor, Camacho, David, editor, Novais, Paulo, editor, and Tallón-Ballesteros, Antonio J., editor

Published
2018
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