Hacking Smart Machines with Smarter Ones: How to Extract Meaningful Data from Machine Learning Classifiers

Machine Learning (ML) algorithms are used to train computers to perform a variety of complex tasks and improve with experience. Computers learn how to recognize patterns, make unintended decisions, or react to a dynamic environment. Certain trained machines may be more effective than others because they are based on more suitable ML algorithms or because they were trained through superior training sets. Although ML algorithms are known and publicly released, training sets may not be reasonably ascertainable and, indeed, may be guarded as trade secrets. While much research has been performed about the privacy of the elements of training sets, in this paper we focus our attention on ML classifiers and on the statistical information that can be unconsciously or maliciously revealed from them. We show that it is possible to infer unexpected but useful information from ML classifiers. In particular, we build a novel meta-classifier and train it to hack other classifiers, obtaining meaningful information about their training sets. This kind of information leakage can be exploited, for example, by a vendor to build more effective classifiers or to simply acquire trade secrets from a competitor's apparatus, potentially violating its intellectual property rights

Remote colorimetric measurements by hyperspectral lidar compared to contact conventional colorimetry

Lidars have many applications in different fields, including the field of Cultural Heritage. The purpose of this study is to evaluate a scanning hyperspectral lidar prototype developed at ENEA Center of Frascati as a useful tool for colorimetric analysis when samples cannot be studied with standard contact instruments. A certified X-Rite Color-checker sample, consisting of 24 colored blocks with a coordinated colorimetric certificate, was analyzed. In order to obtain colorimetric data from the reflectance spectra, the precepts of the Commission de l'Éclairage were followed and an algorithm was developed to calculate the color difference between the certified values of the Color-checker and commercial and non-commercial spectrophotometers and those obtained by the lidar, confirming this latter as a useful tool for remote colorimetry

Long and short term changes in abundance and distribution of butterflies: hints from the Lazio database

The DB on the occurrence data of the butterflies (Papilionoidea) of Lazio, at 14th February 2022 consisted of 36244 records including 154 species istributed throughout a total of 6719 sites. The data set included geoeferenced and chrono-referenced data collected from the literature, specialist-validated occurrences from websites (Forum Natura Mediterraneo, iNaturalist, Ornitho), as well as an important amount of original observations included in the database of the Lazio Biodiversity Observatory. All observations were used to create distribution maps. In order to evaluate any change in observations over time for the various species, all records were divided into three different periods: before 1980 (4425 records), 1980-2000 (6498 records) and post 2000 (25321 records). A finer subdivision was then examined within the post-2000 period: 2001-2007 (11888 records), 2008-2014 (4977 records), 2014-2021 (8456 records). Further analyses were carried out to highlight differences in the distribution of species as a function of altitude and / or changes in land use that have occurred in the last decades. The results show that qualitatively the species present in the region before 1980 are all still present today, however the abundance of related observations in several cases has changed considerably. Observations of an important portion of the species have significantly decreased in recent years. This trend is observed in the majority of mountain species and various habitat-specialist butterflies regardless of altitude. In some other species, often the most common or habitat-generalist butterflies, an increase was observed. The causes of these trends can be identified in the human land use and climate change, without excluding, however, the differences in data recording over time that could favor the most common species

Precisione nella determinazione della lunghezza di lavoro mediante localizzatori elettronici d’apice, radiologia digitale e prova visiva: presentazione di una nuova metodica sperimentale di indagine – uno studio ex-vivo. Exact determination of the working length by electronic apex locators, digital radiology, and visual test: presentation of a new experimental research strategy – an ex-vivo study.

Abstract Objectives: This study compared: 1) the accuracy of three different electronic apex locators (EALs) in detecting the apical foramen ex-vivo under clinical conditions; 2) the accuracy of digital radiography and EALs in determining the K-file position in the root canal; 3) the accuracy of two different radiographic planes; (4) the precision of #10, #15, and #20 K-files in electronic measurements; 5) the precision of EALs in relation to the dental anatomy classification (anterior, bicuspids, and molars). Materials and methods: The length of 101 extracted human teeth was measured with three different EALs (Endex, Propex II and Root ZX), with RVG and compared to the actual length. Experimental procedures were performed using an endodontic training kit (Pro-Train). Results: The statistical analysis showed that Endex and Propex II were more accurate than Root ZX in determining the working length (WL). The t-test showed no statistically significant difference of accuracy between the two radiographic planes examined. The t-test showed no significant difference between the three different K-file size measurements. EALs and RVG are less accurate in anterior teeth. Conclusions: To prevent overestimation of the root canal length using the EALs tested, 1 mm should be subtracted from the measurement on the ‘‘APEX’’ mark. Instrument sizes did not affect the accuracy of EALs. EALs showed to be more accurate in determining the WL than RVG. 2011 Societa` Italiana di Endodonzia. Published by Elsevier Srl. All rights reserved

Self-organizing communication in language games

From the point of view of semiotic dynamics language is an evolving complex dynamical system. In this perspective, unrevealing the mechanisms that allow for the birth of shared conventions is a major issue. Here we describe a very simple model in which agents negotiate conventions and reach a global agreement without any intervention from the outside. In particular we focus on the possibility of predicting on which of the several competing conventions the agreement is reached. We find from simulations that early created conventions are favored in the competition process and this advantage can be quantified. Beyond the specific results presented here, we think that this paper provides an example of a new way of investigating language features where simple models allow for the investigation of precise problems and, possibly, for analytical approaches

ROUNDHOUSE KICK WITH AND WITHOUT IMPACT IN KARATEKA OF DIFFERENT TECHNICAL LEVEL

The purpose of this study was to compare two different Karate roundhouse kicks performed by athletes of different technical level. The combination of high movement velocities and a high technical difficulty, qualify these actions as a good model to quantify the ability of a Karateka to execute complex movements. The first kick, directed to the face, entails a strong braking action to avoid the impact (NI), the other, directed to the chest, is concluded by an impact (IM). Technical aspects and the role of muscular co-activation as joint protector were investigated in six top level Karateka (KA) and six practicing karate amateurs (CO), by estimating joint kinematics and neuromuscular activity patterns. KA presented a faster execution for both tasks, prevalently due to a faster knee extension, supported by a low co-activation of the antagonist Biceps Femoris. This behaviour confirms that elite KA tend to lower the co-activation of antagonist muscles during fast movements, partially in contrast with the antagonists possible role in maintaining knee stability. The NI task, requiring higher technical competence and entailing a high target, is performed by KA athletes using a peculiar technique, based on a wide hip flexion-extension range, with a peak hip ab-adduction occurring earlier than in CO. A lower co-activation presented by CO during knee flexion is presumably due to their difficulty in mastering this complex kick

Multiple scattering approach to DAFS

In this article we outline a general approach to the anomalous correction to the atomic scattering factor ab initio calculation based on the multiple scattering theory. This approach can be used for structural determination in any system and in particular in the surfaces where symmetry conditions make usual analysis impossible. We show as an application of the formalism calculations related to experimental data of bulk Ge

Epitaxial MgB2 thin films on ZrB2 buffer layers: structural characterization by synchrotron radiation

Structural and superconducting properties of magnesium diboride thin films grown by pulsed laser deposition on zirconium diboride buffer layers were studied. We demonstrate that the ZrB2 layer is compatible with the MgB2 two step deposition process. Synchrotron radiation measurements, in particular anomalous diffraction measurements, allowed to separate MgB2 peaks from ZrB2 ones and revealed that both layers have a single in plane orientation with a sharp interface between them. Moreover, the buffer layer avoids oxygen contamination from the sapphire substrate. The critical temperature of this film is near 37.6 K and the upper critical field measured at Grenoble High Magnetic Field Laboratory up to 20.3 T is comparable with the highest ones reported in literature.Comment: 14 pages, 8 figures, submitted to Supercond. Sci. and Techno