1,179 research outputs found
TOWARDS FULLY AUTOMATED DIGITAL ALIBIS WITH SOCIAL INTERACTION
Digital traces found on local hard drives as a result of online activities have become very valuable in reconstructing events in digital forensic investigations. This paper demonstrates that forged alibis can be created for online activities and social interactions. In particular, a novel, automated framework is presented that uses social interactions to create false digital alibis. The framework simulates user activity and supports communications via email as well as instant messaging using a chatbot. The framework is evaluated by extracting forensic artifacts and comparing them with the results obtained from a human user study
A mixed behavioural and data-driven method for assessing the shift potential to electric micromobility: evidence from Rome
Electric micromobility, both as a private option and as a shared service, can represent an alternative to cars, particularly for given user groups (market segments) and specific classes of travel distance. The paper explores the potential for shifting from cars to electric micromobility (specifically, e-bikes and e-scooters) for commuting trips, investigated through floating car data (FCD). The methodology combines the calibration of random utility models (RUMs) and the subsequent simulation through the adoption of FCD spanning the entire city of Rome (Italy). The data used for the calibration of RUM models have been sourced from an online revealed preferences and stated preferences survey carried out between November 2020 and January 2021. Socioeconomic factors, along with transport features (travel time, access time, monetary costs, and perceived safety levels), enter into the definition of the mode choice probability. The first results showed that in Rome, the potential demand for electric micromobility could range between 14% of the FCD sample in the best case (low cost, high accessibility, and road infrastructures with a high perceived level of safety) and about 2% in the worst case (high cost, low accessibility, and a low perceived level of safety)
Delivering in Urban Areas: A Probabilistic-Behavioral Approach for Forecasting the Use of Electric Micromobility
Urban delivering is facing some significant changes that are heading towards unsustainable scenarios. At the same time, local administrations as well as city planners are involved in promoting new solutions that can help to improve city sustainability and livability. In this context, electric micromobility could offer a valuable contribution. In fact, electric micromobility systems such as e-bikes and e-scooters, both at an individual level or as a shared service, could represent sustainable mobility options for city logistics, especially for specific classes of parcel delivery, users’ characteristics and travelled distances. Considering both the growth of e-commerce and the spreading of new options for delivering parcels (e.g., crowdshipping), electric micromobility (e-bikes and e-scooters) could support the penetration and acceptability of such new options, limiting the impacts of delivery operations. After analysis of the current e-commerce background and a review of the current delivery options to satisfy delivery demand, crowdshipping stands out. Thus, the potential shift from private transport to e-micromobility for crowdshipping is investigated, assuming that potential crowdshippers may, mainly, be commuters. The methodology is based on using probabilistic-behavioral models developed within random utility theory, which allow the potential shift towards e-micromobility for commuting to be forecasted. The models were calibrated in Rome, where more than 200 interviews with commuters were available
On the terminal velocity of sedimenting particles in a flowing fluid
The influence of an underlying carrier flow on the terminal velocity of
sedimenting particles is investigated both analytically and numerically. Our
theoretical framework works for a general class of (laminar or turbulent)
velocity fields and, by means of an ordinary perturbation expansion at small
Stokes number, leads to closed partial differential equations (PDE) whose
solutions contain all relevant information on the sedimentation process. The
set of PDE's are solved by means of direct numerical simulations for a class of
2D cellular flows (static and time dependent) and the resulting phenomenology
is analysed and discussed.Comment: 13 pages, 2 figures, submitted to JP
La Asociación Argentina de Estudios Coreanos y su gestión en tiempos complejos (2018-2021)
El presente trabajo escapa a la estructura clásica de una ponencia formal, acercándonos un poco más a contar las alternativas de una asociación académica y sus miembros, frente a la pandemia en un país como la Argentina con una gran potencialidad en aspectos simbólicos y materiales.Centro de Estudios Coreano
Novel Results on the Number of Runs of the Burrows-Wheeler-Transform
The Burrows-Wheeler-Transform (BWT), a reversible string transformation, is
one of the fundamental components of many current data structures in string
processing. It is central in data compression, as well as in efficient query
algorithms for sequence data, such as webpages, genomic and other biological
sequences, or indeed any textual data. The BWT lends itself well to compression
because its number of equal-letter-runs (usually referred to as ) is often
considerably lower than that of the original string; in particular, it is well
suited for strings with many repeated factors. In fact, much attention has been
paid to the parameter as measure of repetitiveness, especially to evaluate
the performance in terms of both space and time of compressed indexing data
structures.
In this paper, we investigate , the ratio of and of the number
of runs of the BWT of the reverse of . Kempa and Kociumaka [FOCS 2020] gave
the first non-trivial upper bound as , for any string
of length . However, nothing is known about the tightness of this upper
bound. We present infinite families of binary strings for which holds, thus giving the first non-trivial lower bound on
, the maximum over all strings of length .
Our results suggest that is not an ideal measure of the repetitiveness of
the string, since the number of repeated factors is invariant between the
string and its reverse. We believe that there is a more intricate relationship
between the number of runs of the BWT and the string's combinatorial
properties.Comment: 14 pages, 2 figue
Insights into the Effect of Lithium Doping on the Deep Eutectic Solvent Choline Chloride: Urea
Choline-based deep eutectic solvents (DESs) are potential candidates to replace flammable
organic solvent electrolytes in lithium-ion batteries (LIBs). The effect of the addition of a lithium salt
on the structure and dynamics of the material needs to be clarified before it enters the battery. Here,
the archetypical DES choline chloride:urea at 1:2 mole fraction has been added with lithium chloride
at two different concentrations and the effect of the additional cation has been evaluated with
respect to the non-doped system via multinuclear NMR techniques. 1H and 7Li spin-lattice
relaxation times and diffusion coefficients have been measured between 298 K and 373 K and
revealed a decrease in both rotational and translational mobility of the species after LiCl doping at
a given temperature. Temperature dependent 35Cl linewidths reflect the viscosity increase upon LiCl
addition, yet keep track of the lithium complexation. Quantitative indicators such as correlation
times and activation energies give indirect insights into the intermolecular interactions of the
mixtures, while lithium single-jump distance and transference number shed light into the lithium
transport, being then of help in the design of future DES electrolytes
Key Indistinguishability vs. Strong Key Indistinguishability for Hierarchical Key Assignment Schemes
A hierarchical key assignment scheme is a method to assign some private information and encryption keys to a set of classes in a partially ordered hierarchy, in such a way that the private information of a higher class can be used to derive the keys of all classes lower down in the hierarchy.
In this paper we analyze the security of hierarchical key assignment schemes according to different notions: security with respect to key indistinguishability and against key recovery, as well as the two recently proposed notions of security with respect to strong key indistinguishability and against strong key recovery. We first explore the relations between all security notions and, in particular, we prove that security with respect to strong key indistinguishability is not stronger than the one with respect to key indistinguishability. Afterwards, we propose a general construction yielding a hierarchical key assignment scheme offering security against strong key recovery, given any hierarchical key assignment scheme which guarantees security against key recovery
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