1,179 research outputs found

    TOWARDS FULLY AUTOMATED DIGITAL ALIBIS WITH SOCIAL INTERACTION

    Get PDF
    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

    Get PDF
    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

    Get PDF
    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

    Full text link
    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)

    Get PDF
    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

    Full text link
    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 rr) 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 rr 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 ρ(v)\rho(v), the ratio of rr and of the number of runs of the BWT of the reverse of vv. Kempa and Kociumaka [FOCS 2020] gave the first non-trivial upper bound as ρ(v)=O(log2(n))\rho(v) = O(\log^2(n)), for any string vv of length nn. However, nothing is known about the tightness of this upper bound. We present infinite families of binary strings for which ρ(v)=Θ(logn)\rho(v) = \Theta(\log n) holds, thus giving the first non-trivial lower bound on ρ(n)\rho(n), the maximum over all strings of length nn. Our results suggest that rr 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

    Get PDF
    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

    Get PDF
    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
    corecore