Picking on the family: disrupting android malware triage by forcing misclassification

Machine learning classification algorithms are widely applied to different malware analysis problems because of their proven abilities to learn from examples and perform relatively well with little human input. Use cases include the labelling of malicious samples according to families during triage of suspected malware. However, automated algorithms are vulnerable to attacks. An attacker could carefully manipulate the sample to force the algorithm to produce a particular output. In this paper we discuss one such attack on Android malware classifiers. We design and implement a prototype tool, called IagoDroid, that takes as input a malware sample and a target family, and modifies the sample to cause it to be classified as belonging to this family while preserving its original semantics. Our technique relies on a search process that generates variants of the original sample without modifying their semantics. We tested IagoDroid against RevealDroid, a recent, open source, Android malware classifier based on a variety of static features. IagoDroid successfully forces misclassification for 28 of the 29 representative malware families present in the DREBIN dataset. Remarkably, it does so by modifying just a single feature of the original malware. On average, it finds the first evasive sample in the first search iteration, and converges to a 100% evasive population within 4 iterations. Finally, we introduce RevealDroid*, a more robust classifier that implements several techniques proposed in other adversarial learning domains. Our experiments suggest that RevealDroid* can correctly detect up to 99% of the variants generated by IagoDroid

Training experience as a limiting factor in master long distance runners

En las últimas décadas ha aumentado el número de atletas veteranos en carreras populares de resistencia. El estudio, que incluyó 103 atletas, tuvo el objetivo de analizar cómo influye la edad y los años de experiencia en el rendimiento de corredores veteranos en largas distancias. Para ello se elaboró un cuestionario ad hoc. El análisis de los años de experiencia muestra correlaciones significativas (p<0,05) en todas las distancias de la categoría de 35-39 años, así como en la distancia de 21,1 km en categoría 40-44 años. Por otro lado, en la comparación entre categorías relacionados con el tiempo total, se encontraron diferencias significativas en la distancia de 21,1 km para los grupos de edad de 35-39/45-49 (p=0,014) y 35-39/50-54 (p=0,014) así como en la distancia de 42,2 km para los grupos de edad de 35-39/45-49 (p=0,022) y 45- 49/50-54 (p=0,050). Los años de experiencia parecen ser un factor limitante del rendimientoIn the last decades, the number of recreational master runners in long-distance running events has increased. This study, which included 103 runners, aimed to analyze the influence of age and training experience on master runners' performance over long distances. An ad hoc questionnaire was used. Training experience analysis showed significant correlations (p<0.05) in all distances in the 35-39 years category, as well as in the distance of 21.1 km in the 40-44 years category. Furthermore, in the comparison between categories related to the total time, significant differences were found in 21.1 km distance for age groups of 35-39 / 45-49 (p=0.014) and 35-39 / 50-54 (p= 0.014) as well as in 42.2 km distance for the age groups of 35-39 / 45-49 (p=0.022) and 45-49 / 50- 54 (p=0.050). Training experience appears to be a limiting factor for performance in recreational master runner

Carrier and Light Trapping in Graded Quantum Well Laser Structures

We investigated the carrier and light trapping in GaInAs/AlGaAs single quantum well laser structures by means of time resolved photoluminescence and Raman spectroscopy. The influence of the shape and depth of the confinement potential and of the cavity geometry was studied by using different AlGaAs/GaAs short-period superlattices as barriers. Our results show that grading the optical cavity improves considerably both carrier and light trapping in the quantum well, and that the trapping efficiency is enhanced by increasing the graded confining potential.Comment: PDF-format, 15 pages (including 4 figures), Applied Physics Letters (June 2000

Periodically rippled graphene: growth and spatially resolved electronic structure

We studied the growth of an epitaxial graphene monolayer on Ru(0001). The graphene monolayer covers uniformly the Ru substrate over lateral distances larger than several microns reproducing the structural defects of the Ru substrate. The graphene is rippled with a periodicity dictated by the difference in lattice parameter between C and Ru. The theoretical model predict inhomogeneities in the electronic structure. This is confirmed by measurements in real space by means of scanning tunnelling spectroscopy. We observe electron pockets at the higher parts of the ripples.Comment: 5 page

Non-destructive evaluation of ferromagnetic material thickness using Pulsed Eddy Current sensor detector coil voltage decay rate

© 2018 Elsevier Ltd A ferromagnetic material thickness quantification method based on the decay rate of the Pulsed Eddy Current sensor detector coil voltage is proposed. An expression for the decay rate is derived and the relationship between the decay rate and material thickness is established. Pipe wall thickness estimation is done with a developed circular sensor incorporating the proposed method, and results are evaluated through destructive testing. The decay rate feature has a unique attribute of being lowly dependent on properties such as sensor shape and size, and lift-off, enabling the method to be usable with any detector coil-based sensor. A case study on using the proposed method with a commercial sensor is also presented to demonstrate its versatility

Potential reactivity of the andesitic rocks from Cabo de Gata (SE Spain)

8 páginas, 4 figuras, 3 tablas.[ES] Las rocas andesíticas producen una reacción álcalis-sílice con los componentes de la fase intersticial del hormigón. Esta reacción puede encuadrarse dentro de las de cinética lenta, ya que la disolución incongruente de los minerales constituyentes de las rocas, da lugar a la formación tardía de geles silicocalco- alcalinos. En consecuencia, la utilización convencional del método de ensayo de barras de mortero no detecta la reacción hasta transcurridos al menos 90 días.[EN] Andesitic rocks produce an alkali-silica reaction with the components of the interstitial phase of concrete. This reaction can be considered as belonging to the slow-kinetic type, since the incongruent dissolution of the rock-forming minerals leads to the late formation of siliceous calc-alkaline gel. As a conquence, the conventional mortar-bar method does not detect such reaction until 90 days later.Peer reviewe

Equivalence of two approaches for the inhomogeneous density in the canonical ensemble

In this article we show that the inhomogeneous density obtained from a density-functional theory of classical fluids in the canonical ensemble (CE), recently presented by White et al [Phys. Rev. Lett. 84 (2000) 1220], is equivalent to first order to the result of the series expansion of the CE inhomogeneous density introduced by Gonzalez et al [Phys. Rev. Lett. 79 (1997) 2466].Comment: 6 pages, RevTe