62 research outputs found

    Vote buying revisited: implications for receipt-freeness

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    In this paper, we analyse the concept of vote buying based on examples that try to stretch the meaning of the concept. Which ex- amples can still be called vote buying, and which cannot? We propose several dimensions that are relevant to qualifying an action as vote buy- ing or not. As a means of protection against vote buying and coercion, the concept of receipt-freeness has been proposed. We argue that, in or- der to protect against a larger set of vote buying activities, the concept of receipt-freeness should be interpreted probabilistically. We propose a general definition of probabilistic receipt-freeness by adapting existing definitions of probabilistic anonymity to voting

    Core security requirements of DRM systems

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    A Formal Framework for Modelling Coercion Resistance and Receipt Freeness

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    Abstract. Coercion resistance and receipt freeness are critical proper-ties for any voting system. However, many different definitions of these properties have been proposed, some formal and some informal; and there has been little attempt to tie these definitions together or identify rela-tions between them. We give here a general framework for specifying different coercion re-sistance and receipt freeness properties using the process algebra CSP. The framework is general enough to accommodate a wide range of defini-tions, and strong enough to cover both randomization attacks and forced abstention attacks. We provide models of some simple voting systems, and show how the framework can be used to analyze these models un-der different definitions of coercion resistance and receipt freeness. Our formalisation highlights the variation between the definitions, and the importance of understanding the relations between them.

    Estado nutricional vinculado a ingesta alimentaria y actividad física que realizan estudiantes de séptimo grado de tres colegios privados. Managua-Nicaragua. Abril-Agosto 2015.

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    Estudio descriptivo de corte transversal en 150 estudiantes de séptimo grado de los colegios: Mi Redentor, Bautista y Jesús Divino Obrero del departamento de Managua. Se concluye que más de la mitad de estudiantes, presentaron estado nutricional normal. Coexiste malnutrición por déficit, y por exceso, asociado al riesgo cardiovascular y antecedentes patológicos familiares de hipertensión y diabetes. El desayuno es la comida que se saltaron con mayor frecuencia. El patrón alimentario lo conforman trece alimentos. La práctica de actividades físicas que realizan: caminar, correr, montar en bicicleta, jugar futbol, voleibol y baloncesto. En la clase de educación física los alumnos están siempre y algunas veces activos

    Urban coral reefs: Degradation and resilience of hard coral assemblages in coastal cities of East and Southeast Asia

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    © 2018 The Author(s) Given predicted increases in urbanization in tropical and subtropical regions, understanding the processes shaping urban coral reefs may be essential for anticipating future conservation challenges. We used a case study approach to identify unifying patterns of urban coral reefs and clarify the effects of urbanization on hard coral assemblages. Data were compiled from 11 cities throughout East and Southeast Asia, with particular focus on Singapore, Jakarta, Hong Kong, and Naha (Okinawa). Our review highlights several key characteristics of urban coral reefs, including “reef compression” (a decline in bathymetric range with increasing turbidity and decreasing water clarity over time and relative to shore), dominance by domed coral growth forms and low reef complexity, variable city-specific inshore-offshore gradients, early declines in coral cover with recent fluctuating periods of acute impacts and rapid recovery, and colonization of urban infrastructure by hard corals. We present hypotheses for urban reef community dynamics and discuss potential of ecological engineering for corals in urban areas

    Search for Gravitational Waves Associated with Gamma-Ray Bursts Detected by Fermi and Swift during the LIGO-Virgo Run O3b

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    We search for gravitational-wave signals associated with gamma-ray bursts (GRBs) detected by the Fermi and Swift satellites during the second half of the third observing run of Advanced LIGO and Advanced Virgo (2019 November 1 15:00 UTC-2020 March 27 17:00 UTC). We conduct two independent searches: A generic gravitational-wave transients search to analyze 86 GRBs and an analysis to target binary mergers with at least one neutron star as short GRB progenitors for 17 events. We find no significant evidence for gravitational-wave signals associated with any of these GRBs. A weighted binomial test of the combined results finds no evidence for subthreshold gravitational-wave signals associated with this GRB ensemble either. We use several source types and signal morphologies during the searches, resulting in lower bounds on the estimated distance to each GRB. Finally, we constrain the population of low-luminosity short GRBs using results from the first to the third observing runs of Advanced LIGO and Advanced Virgo. The resulting population is in accordance with the local binary neutron star merger rate. © 2022. The Author(s). Published by the American Astronomical Society

    Narrowband Searches for Continuous and Long-duration Transient Gravitational Waves from Known Pulsars in the LIGO-Virgo Third Observing Run

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    Isolated neutron stars that are asymmetric with respect to their spin axis are possible sources of detectable continuous gravitational waves. This paper presents a fully coherent search for such signals from eighteen pulsars in data from LIGO and Virgo's third observing run (O3). For known pulsars, efficient and sensitive matched-filter searches can be carried out if one assumes the gravitational radiation is phase-locked to the electromagnetic emission. In the search presented here, we relax this assumption and allow both the frequency and the time derivative of the frequency of the gravitational waves to vary in a small range around those inferred from electromagnetic observations. We find no evidence for continuous gravitational waves, and set upper limits on the strain amplitude for each target. These limits are more constraining for seven of the targets than the spin-down limit defined by ascribing all rotational energy loss to gravitational radiation. In an additional search, we look in O3 data for long-duration (hours-months) transient gravitational waves in the aftermath of pulsar glitches for six targets with a total of nine glitches. We report two marginal outliers from this search, but find no clear evidence for such emission either. The resulting duration-dependent strain upper limits do not surpass indirect energy constraints for any of these targets. © 2022. The Author(s). Published by the American Astronomical Society
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