Neural Networks retrieving Boolean patterns in a sea of Gaussian ones

Restricted Boltzmann Machines are key tools in Machine Learning and are described by the energy function of bipartite spin-glasses. From a statistical mechanical perspective, they share the same Gibbs measure of Hopfield networks for associative memory. In this equivalence, weights in the former play as patterns in the latter. As Boltzmann machines usually require real weights to be trained with gradient descent like methods, while Hopfield networks typically store binary patterns to be able to retrieve, the investigation of a mixed Hebbian network, equipped with both real (e.g., Gaussian) and discrete (e.g., Boolean) patterns naturally arises. We prove that, in the challenging regime of a high storage of real patterns, where retrieval is forbidden, an extra load of Boolean patterns can still be retrieved, as long as the ratio among the overall load and the network size does not exceed a critical threshold, that turns out to be the same of the standard Amit-Gutfreund-Sompolinsky theory. Assuming replica symmetry, we study the case of a low load of Boolean patterns combining the stochastic stability and Hamilton-Jacobi interpolating techniques. The result can be extended to the high load by a non rigorous but standard replica computation argument.Comment: 16 pages, 1 figur

Burn after reading: A shadow stack with microsecond-level runtime rerandomization for protecting return addresses

Return-oriented programming (ROP) is an effective code-reuse attack in which short code sequences (i.e., gadgets) ending in a ret instruction are found within existing binaries and then executed by taking control of the call stack. The shadow stack, control flow integrity (CFI) and code (re)randomization are three popular techniques for protecting programs against return address overwrites. However, existing runtime rerandomization techniques operate on concrete return addresses, requiring expensive pointer tracking. By adding one level of indirection, we introduce BarRA, the first shadow stack mechanism that applies continuous runtime rerandomization to abstract return addresses for protecting their corresponding concrete return addresses (protected also by CFI), thus avoiding expensive pointer tracking. As a nice side-effect, BarRA naturally combines the shadow stack, CFI and runtime rerandomization in the same framework. The key novelty of BarRA, however, is that once some abstract return addresses are leaked, BarRA will enforce the burn-after-reading property by rerandomizing the mapping from the abstract to the concrete return address space in the order of microseconds instead of seconds required for rerandomizing a concrete return address space. As a result, BarRA can be used as a superior replacement for the shadow stack, as demonstrated by comparing both using the 19 C/C++ benchmarks in SPEC CPU2006 (totalling 2,047,447 LOC) and analyzing a proof-of-concept attack, provided that we can tolerate some slight binary code size increases (by an average of 29.44%) and are willing to use 8MB of dedicated memory for holding up to 220 return addresses (on a 64-bit platform). Under an information leakage attack (for some return addresses), the shadow stack is always vulnerable but BarRA is significantly more resilient (by reducing an attacker's success rate to 1 220 on average). In terms of the average performance overhead introduced, both are comparable: 6.09% (BarRA) vs. 5.38% (the shadow stack)

Do you know this syndrome? Nail patela syndrome: a pathognomonic dermatologic finding

Hosp Barra DOr, Unidade Neurointens, Rio De Janeiro, RJ, BrazilUniv Fed Sao Paulo UNIFESP, Dept Clin Med, Escola Paulista Med, Sao Paulo, SP, BrazilHosp Barra DOr, Intens Care Dept, Rio De Janeiro, RJ, BrazilUniv Fed Sao Paulo UNIFESP, Dept Clin Med, Escola Paulista Med, Sao Paulo, SP, BrazilWeb of Scienc

Acquaintance role for decision making and exchanges in social networks

We model a social network by a random graph whose nodes represent agents and links between two of them stand for a reciprocal interaction; each agent is also associated to a binary variable which represents a dichotomic opinion or attribute. We consider both the case of pair-wise (p=2) and multiple (p>2) interactions among agents and we study the behavior of the resulting system by means of the energy-entropy scheme, typical of statistical mechanics methods. We show, analytically and numerically, that the connectivity of the social network plays a non-trivial role: while for pair-wise interactions (p=2) the connectivity weights linearly, when interactions involve contemporary a number of agents larger than two (p>2), its weight gets more and more important. As a result, when p is large, a full consensus within the system, can be reached at relatively small critical couplings with respect to the p=2 case usually analyzed, or, otherwise stated, relatively small coupling strengths among agents are sufficient to orient most of the system.Comment: 7 pages, 1 figur

Lírica y épica. La Tercera Residencia

Análisis de la obra "Residencia en la Tierra" del poeta Pablo Neruda

Investigations on the Peach 4 Debrite, a Late Pleistocene Mass Movement on the Northwest British Continental Margin

The Peach 4 debrite is the most recent in a series of large scale Pleistocene MTDs within the Barra fan on the northwest British continental margin. Geophysical data indicate that Peach 4 was formed through a combination of blocky and muddy debris flows and affects an area of ~ 700 km2. BGS core sample 56 -10 36, located directly over the Peach 4 debrite, provides a minimum age of 14.68 ka cal BP for the last major failure. An upwards fining turbidite sequence in BGS core sample 56 -10 239 is associ-ated with increased As and S concentrations, indicators of diagenetic pyrite which forms under anoxic conditions. It is proposed that As and S concentrations may pro-vide a method of distinguishing between contourite and turbidite sedimentation, though further research is required

Mathematical modelling of tilt-rotor aircraft configurations. A comprehensive model for flight control system development and real-time piloted simulation.

L'abstract è presente nell'allegato / the abstract is in the attachmen

Un silicoflagelado en el Albiano medio de la Cuenca Austral, Argentina

Calcareous nannofossil biostratigraphic investigations of Cretaceous sediments within the southern high latitude Austral Basin, Argentina, have revealed the presence of a fragment of a silicoflagellate possibly belonging to the species Variramus aculeifera (Deflandre) McCartney, Wise, Harwood and Gersonde. Although only a fragment was identified in the samples examined from this locality, its presence is important, as it is only the second documented occurrence of an Early Cretaceous silicoflagellate. The specimen was found in a subsurface sample from the informal Palermo Aike Formation at Austral Basin. This stratigraphic level is interpreted as middle Albian on the basis of calcareous nannofossil biostratigraphy. The specimen consists of a fragmented strut with broken spines at the base, which allows the observation of the hollow skeletal structure. The strut is curved and slightly expanded at the widest part, which are characteristics diagnostic of the genus Variramus.Estudios sobre nanofósiles calcáreos en sedimentitas cretácicas de la Cuenca Austral, Argentina, revelaron la presencia de un fragmento de un silicoflagelado, posiblemente de Variramus aculeifera (Deflandre) McCartney, Wise, Harwood and Gersonde. A pesar de que se recuperó solo un fragmento, su presencia es importante porque representa el segundo registro de silicoflage-lados del Cretácico Temprano. El espécimen fue hallado en una muestra de subsuelo correspondiente a la Formación Palermo Aike, en la Cuenca Austral. Ese nivel estratigráfico fue interpretado como Albiano medio sobre la base de los nanofósiles calcáreos. El ejemplar corresponde al fragmento de una barra con espinas rotas en la base, que permitieron observar la naturaleza hueca del esqueleto silíceo. La barra es curva y presenta un leve ensanchamiento, dos características diagnósticas del género Variarmus.Fil: Perez Panera, Juan Pablo. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo; Argentin

An Economy-Wide Perspective on Earnings Data in Ireland: Methodological Issues and Analysis. ESRI WP156. 2004

The objective of this article is to give a detailed description as to how earnings data is recorded in the Irish economy and to develop new methods of presenting this data in order to give a more comprehensive picture of wage movements over the period since 1998. Currently, earnings data are published by the Central Statistics Office (CSO) on a sectoral basis with similar methodological backgrounds across the surveys. However, the surveys can vary though in terms of their scope. For example the industrial earnings survey presents both hourly and weekly earnings series’ while the distribution & business services earnings survey contains just weekly earnings data. The type of worker being surveyed can also vary, some surveys covering all workers and other surveys covering just full-time workers. Therefore, a discussion of the various sectoral earnings surveys is necessary

A case of 'new Soviet internationalism' : relations between the USSR and Chile's Christian Democratic government, 1964–1970

After Iosif Stalin's death in 1953, the Soviet Union emerged from its isolation and began to show an interest in traditionally marginalized foreign societies. As the example of the Chilean-Soviet rapprochement under Eduardo Frei's administration (1964–1970) shows, Soviet leaders viewed state-to-state relations with "progressive" Latin American regimes as an appropriate means of undermining U.S. influence in the region without risking an armed confrontation with "imperialism." The reformist project of the Chilean Christian Democratic government, which included a diplomatic opening to the Soviet bloc, provided a testing ground for the suitability of Moscow's new global approach. The surge of cultural and political exchanges indicate that the Soviet authorities were keenly interested in the Chilean experience. In addition, the considerable growth of travel and official missions beyond the Iron Curtain also demonstrates that Santiago wished to benefit by diversifying its international partners