Elements of Non-Linear Hamiltonian Dynamics

In this paper we present a set of generic results on Hamiltonian non-linear dynamics. We show the necessary conditions for a Hamiltonian system to present a non-twist scenario and from that we introduce the isochronous resonances. The generality of these resonances is shown from the Hamiltonian given by the Birkhof-Gustavson normal form, which can be considered a toy model, and from an optic system governed by the non-linear map of the annular billiard. We also define a special kind of transport barrier called robust torus. The meanders and shearless curves are also presented and we show the most robust shearless barrier associated with the rotation numbers.

Birth of limit cycles bifurcating from a nonsmooth center

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Disfunção craniomandibular e sua correlação com radiografia transcraniana da articulação temporomandibular: estudo comparativo entre indivíduos portadores de sintomas severos pelo índice de helkimo e indivíduos assintomáticos

Pós-graduação em Odontologia Restauradora - ICT

Nonlocal dissipative tunneling for high-fidelity quantum-state transfer between distant parties

In this work, we propose the nonlocal tunneling mechanism for high-fidelity state transfer between distant parties. The nonlocal tunneling follows from the overlap between the distant sending and receiving wave functions, which is indirectlymediated by the off-resonant normal modes of a quantum channel. This channel is made up of a network of dissipative quantum systems exhibiting the same bosonic or fermionic statistical nature as the sender and receiver. We demonstrate that the incoherence arising from quantum channel nonidealities is almost completely circumvented by the tunneling mechanism, which thus affords a high-fidelity transfer process.

Miniversal deformations of matrices of bilinear forms

Arnold [V.I. Arnold, On matrices depending on parameters, Russian Math. Surveys 26 (2) (1971) 29-43] constructed miniversal deformations of square complex matrices under similarity; that is, a simple normal form to which not only a given square matrix A but all matrices B close to it can be reduced by similarity transformations that smoothly depend on the entries of B. We construct miniversal deformations of matrices under congruence. (C) 2011 Elsevier Inc. All rights reserved.

Modeling and identification of freeplay nonlinearity

A nonlinear analysis is performed for the purpose of identification of the pitch freeplay nonlinearity and its effect on the type of bifurcation of a two degree-of-freedom aeroelastic system. The databases for the identification are generated from experimental investigations of a pitch-plunge rigid airfoil supported by a nonlinear torsional spring. Experimental data and linear analysis are performed to validate the parameters of the linearized equations. Based on the periodic responses of the experimental data which included the flutter frequency and its third harmonics, the freeplay nonlinearity is approximated by a polynomial expansion up to the third order. This representation allows us to use the normal form of the Hopf bifurcation to characterize the type of instability. Based on numerical integrations, the coefficients of the polynomial expansion representing the freeplay nonlinearity are identified. Published by Elsevier Ltd.

Bifurcation analysis of an aeroelastic system with concentrated nonlinearities

Analytical and numerical analyses of the nonlinear response of a three-degree-of-freedom nonlinear aeroelastic system are performed. Particularly, the effects of concentrated structural nonlinearities on the different motions are determined. The concentrated nonlinearities are introduced in the pitch, plunge, and flap springs by adding cubic stiffness in each of them. Quasi-steady approximation and the Duhamel formulation are used to model the aerodynamic loads. Using the quasi-steady approach, we derive the normal form of the Hopf bifurcation associated with the system's instability. Using the nonlinear form, three configurations including supercritical and subcritical aeroelastic systems are defined and analyzed numerically. The characteristics of these different configurations in terms of stability and motions are evaluated. The usefulness of the two aerodynamic formulations in the prediction of the different motions beyond the bifurcation is discussed.

Identification of logically related heap regions

This paper introduces a novel technique for identifying logically related sections of the heap such as recursive data structures, objects that are part of the same multi-component structure, and related groups of objects stored in the same collection/array. When combined withthe lifetime properties of these structures, this information can be used to drive a range of program optimizations including pool allocation, object co-location, static deallocation, and region-based garbage collection. The technique outlined in this paper also improves the efficiency of the static analysis by providing a normal form for the abstract models (speeding the convergence of the static analysis). We focus on two techniques for grouping parts of the heap. The first is a technique for precisely identifying recursive data structures in object-oriented programs based on the types declared in the program. The second technique is a novel method for grouping objects that make up the same composite structure and that allows us to partition the objects stored in a collection/array into groups based on a similarity relation. We provide a parametric component in the similarity relation in order to support specific analysis applications (such as a numeric analysis which would need to partition the objects based on numeric properties of the fields). Using the Barnes-Hut benchmark from the JOlden suite we show how these grouping methods can be used to identify various types of logical structures allowing the application of many region-based program optimizations.

Cooperative Multi-robot Patrolling: A study of distributed approaches based on mathematical models of game theory to protect infrastructures

El principio de Teoría de Juegos permite desarrollar modelos estocásticos de patrullaje multi-robot para proteger infraestructuras criticas. La protección de infraestructuras criticas representa un gran reto para los países al rededor del mundo, principalmente después de los ataques terroristas llevados a cabo la década pasada. En este documento el termino infraestructura hace referencia a aeropuertos, plantas nucleares u otros instalaciones. El problema de patrullaje se define como la actividad de patrullar un entorno determinado para monitorear cualquier actividad o sensar algunas variables ambientales. En esta actividad, un grupo de robots debe visitar un conjunto de puntos de interés definidos en un entorno en intervalos de tiempo irregulares con propósitos de seguridad. Los modelos de partullaje multi-robot son utilizados para resolver este problema. Hasta el momento existen trabajos que resuelven este problema utilizando diversos principios matemáticos. Los modelos de patrullaje multi-robot desarrollados en esos trabajos representan un gran avance en este campo de investigación. Sin embargo, los modelos con los mejores resultados no son viables para aplicaciones de seguridad debido a su naturaleza centralizada y determinista. Esta tesis presenta cinco modelos de patrullaje multi-robot distribuidos e impredecibles basados en modelos matemáticos de aprendizaje de Teoría de Juegos. El objetivo del desarrollo de estos modelos está en resolver los inconvenientes presentes en trabajos preliminares. Con esta finalidad, el problema de patrullaje multi-robot se formuló utilizando conceptos de Teoría de Grafos, en la cual se definieron varios juegos en cada vértice de un grafo. Los modelos de patrullaje multi-robot desarrollados en este trabajo de investigación se han validado y comparado con los mejores modelos disponibles en la literatura. Para llevar a cabo tanto la validación como la comparación se ha utilizado un simulador de patrullaje y un grupo de robots reales. Los resultados experimentales muestran que los modelos de patrullaje desarrollados en este trabajo de investigación trabajan mejor que modelos de trabajos previos en el 80% de 150 casos de estudio. Además de esto, estos modelos cuentan con varias características importantes tales como distribución, robustez, escalabilidad y dinamismo. Los avances logrados con este trabajo de investigación dan evidencia del potencial de Teoría de Juegos para desarrollar modelos de patrullaje útiles para proteger infraestructuras. ABSTRACT Game theory principle allows to developing stochastic multi-robot patrolling models to protect critical infrastructures. Critical infrastructures protection is a great concern for countries around the world, mainly due to terrorist attacks in the last decade. In this document, the term infrastructures includes airports, nuclear power plants, and many other facilities. The patrolling problem is defined as the activity of traversing a given environment to monitoring any activity or sensing some environmental variables If this activity were performed by a fleet of robots, they would have to visit some places of interest of an environment at irregular intervals of time for security purposes. This problem is solved using multi-robot patrolling models. To date, literature works have been solved this problem applying various mathematical principles.The multi-robot patrolling models developed in those works represent great advances in this field. However, the models that obtain the best results are unfeasible for security applications due to their centralized and predictable nature. This thesis presents five distributed and unpredictable multi-robot patrolling models based on mathematical learning models derived from Game Theory. These multi-robot patrolling models aim at overcoming the disadvantages of previous work. To this end, the multi-robot patrolling problem was formulated using concepts of Graph Theory to represent the environment. Several normal-form games were defined at each vertex of a graph in this formulation. The multi-robot patrolling models developed in this research work have been validated and compared with best ranked multi-robot patrolling models in the literature. Both validation and comparison were preformed by using both a patrolling simulator and real robots. Experimental results show that the multirobot patrolling models developed in this research work improve previous ones in as many as 80% of 150 cases of study. Moreover, these multi-robot patrolling models rely on several features to highlight in security applications such as distribution, robustness, scalability, and dynamism. The achievements obtained in this research work validate the potential of Game Theory to develop patrolling models to protect infrastructures.

Securing implementations of feedback-shift-register-based ciphers using compiler optimizations and co-processors

Los algoritmos basados en registros de desplazamiento con realimentación (en inglés FSR) se han utilizado como generadores de flujos pseudoaleatorios en aplicaciones con recursos limitados como los sistemas de apertura sin llave. Se considera canal primario a aquel que se utiliza para realizar una transmisión de información. La aparición de los ataques de canal auxiliar (en inglés SCA), que explotan información filtrada inintencionadamente a través de canales laterales como el consumo, las emisiones electromagnéticas o el tiempo empleado, supone una grave amenaza para estas aplicaciones, dado que los dispositivos son accesibles por un atacante. El objetivo de esta tesis es proporcionar un conjunto de protecciones que se puedan aplicar de forma automática y que utilicen recursos ya disponibles, evitando un incremento sustancial en los costes y alargando la vida útil de aplicaciones que puedan estar desplegadas. Explotamos el paralelismo existente en algoritmos FSR, ya que sólo hay 1 bit de diferencia entre estados de rondas consecutivas. Realizamos aportaciones en tres niveles: a nivel de sistema, utilizando un coprocesador reconfigurable, a través del compilador y a nivel de bit, aprovechando los recursos disponibles en el procesador. Proponemos un marco de trabajo que nos permite evaluar implementaciones de un algoritmo incluyendo los efectos introducidos por el compilador considerando que el atacante es experto. En el campo de los ataques, hemos propuesto un nuevo ataque diferencial que se adapta mejor a las condiciones de las implementaciones software de FSR, en las que el consumo entre rondas es muy similar. SORU2 es un co-procesador vectorial reconfigurable propuesto para reducir el consumo energético en aplicaciones con paralelismo y basadas en el uso de bucles. Proponemos el uso de SORU2, además, para ejecutar algoritmos basados en FSR de forma segura. Al ser reconfigurable, no supone un sobrecoste en recursos, ya que no está dedicado en exclusiva al algoritmo de cifrado. Proponemos una configuración que ejecuta múltiples algoritmos de cifrado similares de forma simultánea, con distintas implementaciones y claves. A partir de una implementación sin protecciones, que demostramos que es completamente vulnerable ante SCA, obtenemos una implementación segura a los ataques que hemos realizado. A nivel de compilador, proponemos un mecanismo para evaluar los efectos de las secuencias de optimización del compilador sobre una implementación. El número de posibles secuencias de optimizaciones de compilador es extremadamente alto. El marco de trabajo propuesto incluye un algoritmo para la selección de las secuencias de optimización a considerar. Debido a que las optimizaciones del compilador transforman las implementaciones, se pueden generar automáticamente implementaciones diferentes combinamos para incrementar la seguridad ante SCA. Proponemos 2 mecanismos de aplicación de estas contramedidas, que aumentan la seguridad de la implementación original sin poder considerarse seguras. Finalmente hemos propuesto la ejecución paralela a nivel de bit del algoritmo en un procesador. Utilizamos la forma algebraica normal del algoritmo, que automáticamente se paraleliza. La implementación sobre el algoritmo evaluado mejora en rendimiento y evita que se filtre información por una ejecución dependiente de datos. Sin embargo, es más vulnerable ante ataques diferenciales que la implementación original. Proponemos una modificación del algoritmo para obtener una implementación segura, descartando parcialmente ejecuciones del algoritmo, de forma aleatoria. Esta implementación no introduce una sobrecarga en rendimiento comparada con las implementaciones originales. En definitiva, hemos propuesto varios mecanismos originales a distintos niveles para introducir aleatoridad en implementaciones de algoritmos FSR sin incrementar sustancialmente los recursos necesarios. ABSTRACT Feedback Shift Registers (FSR) have been traditionally used to implement pseudorandom sequence generators. These generators are used in Stream ciphers in systems with tight resource constraints, such as Remote Keyless Entry. When communicating electronic devices, the primary channel is the one used to transmit the information. Side-Channel Attack (SCA) use additional information leaking from the actual implementation, including power consumption, electromagnetic emissions or timing information. Side-Channel Attacks (SCA) are a serious threat to FSR-based applications, as an attacker usually has physical access to the devices. The main objective of this Ph.D. thesis is to provide a set of countermeasures that can be applied automatically using the available resources, avoiding a significant cost overhead and extending the useful life of deployed systems. If possible, we propose to take advantage of the inherent parallelism of FSR-based algorithms, as the state of a FSR differs from previous values only in 1-bit. We have contributed in three different levels: architecture (using a reconfigurable co-processor), using compiler optimizations, and at bit level, making the most of the resources available at the processor. We have developed a framework to evaluate implementations of an algorithm including the effects introduced by the compiler. We consider the presence of an expert attacker with great knowledge on the application and the device. Regarding SCA, we have presented a new differential SCA that performs better than traditional SCA on software FSR-based algorithms, where the leaked values are similar between rounds. SORU2 is a reconfigurable vector co-processor. It has been developed to reduce energy consumption in loop-based applications with parallelism. In addition, we propose its use for secure implementations of FSR-based algorithms. The cost overhead is discarded as the co-processor is not exclusively dedicated to the encryption algorithm. We present a co-processor configuration that executes multiple simultaneous encryptions, using different implementations and keys. From a basic implementation, which is proved to be vulnerable to SCA, we obtain an implementation where the SCA applied were unsuccessful. At compiler level, we use the framework to evaluate the effect of sequences of compiler optimization passes on a software implementation. There are many optimization passes available. The optimization sequences are combinations of the available passes. The amount of sequences is extremely high. The framework includes an algorithm for the selection of interesting sequences that require detailed evaluation. As existing compiler optimizations transform the software implementation, using different optimization sequences we can automatically generate different implementations. We propose to randomly switch between the generated implementations to increase the resistance against SCA.We propose two countermeasures. The results show that, although they increase the resistance against SCA, the resulting implementations are not secure. At bit level, we propose to exploit bit level parallelism of FSR-based implementations using pseudo bitslice implementation in a wireless node processor. The bitslice implementation is automatically obtained from the Algebraic Normal Form of the algorithm. The results show a performance improvement, avoiding timing information leakage, but increasing the vulnerability against differential SCA.We provide a secure version of the algorithm by randomly discarding part of the data obtained. The overhead in performance is negligible when compared to the original implementations. To summarize, we have proposed a set of original countermeasures at different levels that introduce randomness in FSR-based algorithms avoiding a heavy overhead on the resources required.

Vector Boolean Functions: Applications in Symmetric Cryptography

Esta tesis establece los fundamentos teóricos y diseña una colección abierta de clases C++ denominada VBF (Vector Boolean Functions) para analizar funciones booleanas vectoriales (funciones que asocian un vector booleano a otro vector booleano) desde una perspectiva criptográfica. Esta nueva implementación emplea la librería NTL de Victor Shoup, incorporando nuevos módulos que complementan a las funciones de NTL, adecuándolas para el análisis criptográfico. La clase fundamental que representa una función booleana vectorial se puede inicializar de manera muy flexible mediante diferentes estructuras de datas tales como la Tabla de verdad, la Representación de traza y la Forma algebraica normal entre otras. De esta manera VBF permite evaluar los criterios criptográficos más relevantes de los algoritmos de cifra en bloque y de stream, así como funciones hash: por ejemplo, proporciona la no-linealidad, la distancia lineal, el grado algebraico, las estructuras lineales, la distribución de frecuencias de los valores absolutos del espectro Walsh o del espectro de autocorrelación, entre otros criterios. Adicionalmente, VBF puede llevar a cabo operaciones entre funciones booleanas vectoriales tales como la comprobación de igualdad, la composición, la inversión, la suma, la suma directa, el bricklayering (aplicación paralela de funciones booleanas vectoriales como la empleada en el algoritmo de cifra Rijndael), y la adición de funciones coordenada. La tesis también muestra el empleo de la librería VBF en dos aplicaciones prácticas. Por un lado, se han analizado las características más relevantes de los sistemas de cifra en bloque. Por otro lado, combinando VBF con algoritmos de optimización, se han diseñado funciones booleanas cuyas propiedades criptográficas son las mejores conocidas hasta la fecha. ABSTRACT This thesis develops the theoretical foundations and designs an open collection of C++ classes, called VBF, designed for analyzing vector Boolean functions (functions that map a Boolean vector to another Boolean vector) from a cryptographic perspective. This new implementation uses the NTL library from Victor Shoup, adding new modules which complement the existing ones making VBF better suited for cryptography. The fundamental class representing a vector Boolean function can be initialized in a flexible way via several alternative types of data structures such as Truth Table, Trace Representation, Algebraic Normal Form (ANF) among others. This way, VBF allows the evaluation of the most relevant cryptographic criteria for block and stream ciphers as well as for hash functions: for instance, it provides the nonlinearity, the linearity distance, the algebraic degree, the linear structures, the frequency distribution of the absolute values of the Walsh Spectrum or the Autocorrelation Spectrum, among others. In addition, VBF can perform operations such as equality testing, composition, inversion, sum, direct sum, bricklayering (parallel application of vector Boolean functions as employed in Rijndael cipher), and adding coordinate functions of two vector Boolean functions. This thesis also illustrates the use of VBF in two practical applications. On the one hand, the most relevant properties of the existing block ciphers have been analysed. On the other hand, by combining VBF with optimization algorithms, new Boolean functions have been designed which have the best known cryptographic properties up-to-date.

Characterization of the transforming activity of p80, a hyperphosphorylated protein in a Ki-1 lymphoma cell line with chromosomal translocation t(2;5).

We have molecularly cloned a cDNA encoding a protein uniquely expressed and hyperphosphorylated at tyrosine residues in a Ki-1 lymphoma cell that contained chromosomal translocation t(2;5). The encoded protein p80 was shown to be generated by fusion of a protein-tyrosine kinase and a nucleolar protein B23/nucleophosmin (NPM). The coding sequence of this cDNA turned out to be virtually identical to that of the fusion cDNA for NPM-anaplastic lymphoma kinase (ALK) previously cloned from the transcript of the gene at the breakpoint of the same translocation. Overexpression of p80 in NIH 3T3 cells induced neoplastic transformation, suggesting that the p80 kinase is aberrantly activated. The normal form of p80 was predicted to be a receptor-type tyrosine kinase on the basis of its sequence similarity to the insulin receptor family of kinases. However, an immunofluorescence study using COS cells revealed that p80 was localized to the cytoplasm. Thus, subcellular translocation and activation of the tyrosine kinase presumably by its structural alteration would cause the malignant transformation. We also showed that a mutant p80 lacking the NPM portion was unable to transform NIH 3T3 cells. Thus, the NPM sequence is essential for the transforming activity, suggesting that the chromosomal translocation is responsible for the oncogenesis. Finally, Shc and insulin receptor substrate 1 (IRS-1) were tyrosine-phosphorylated and bound to p80 in p80-transformed cells. However, mutants of p80 that were defective for binding to and phosphorylation of Shc and insulin receptor substrate 1 could transform NIH 3T3 cells. Association of these mutants with GRB2 was still observed, suggesting that interaction of p80 with GRB2 but not with Shc or IRS-1 was relevant for cell transformation.

Probabilistic resource space model for managing resources in cyber-physical society

Classification is the most basic method for organizing resources in the physical space, cyber space, socio space and mental space. To create a unified model that can effectively manage resources in different spaces is a challenge. The Resource Space Model RSM is to manage versatile resources with a multi-dimensional classification space. It supports generalization and specialization on multi-dimensional classifications. This paper introduces the basic concepts of RSM, and proposes the Probabilistic Resource Space Model, P-RSM, to deal with uncertainty in managing various resources in different spaces of the cyber-physical society. P-RSM’s normal forms, operations and integrity constraints are developed to support effective management of the resource space. Characteristics of the P-RSM are analyzed through experiments. This model also enables various services to be described, discovered and composed from multiple dimensions and abstraction levels with normal form and integrity guarantees. Some extensions and applications of the P-RSM are introduced.

Holocene Mg/Ca, alkenones, and light stable isotope measurements on the outer North Iceland shelf, sediment core MD99-2269

We present new Holocene century to millennial-scale proxies for the well-dated piston core MD99-2269 from Húnaflóadjúp on the North Iceland Shelf. The core is located in 365 mwd and lies close to the fluctuating boundary between Atlantic and Arctic/Polar waters. The proxies are: alkenone-based SST°C, and Mg/Ca SST°C estimates and stable d13C and d18O values on planktonic and benthic foraminifera. The data were converted to 60 yr equi-spaced time-series. Significant trends in the data were extracted using Singular Spectrum Analysis and these accounted for between 50% and 70% of the variance. A comparison between these data with previously published climate proxies from MD99-2269 was carried out on a data set which consisted of 14-variable data set covering the interval 400-9200 cal yr BP at 100 yr time steps. This analysis indicated that the 1st two PC axes accounted for 57% of the variability with high loadings clustering primarily into "nutrient" and "temperature" proxies. Clustering on the 100 yr time-series indicated major changes in environment at ~6350 and ~3450 cal yr BP, which define early, mid- and late Holocene climatic intervals. We argue that a pervasive freshwater cap during the early Holocene resulted in warm SST°s, a stratified water column, and a depleted nutrient supply. The loss of the freshwater layer in the mid-Holocene resulted in high carbonate production, and the late Holocene/neoglacial interval was marked by significantly more variable sea surface conditions.

(Table 1) Late Pleistocene planktonic foraminifera of Hole 302-M0004C

Planktonic foraminifera populations were studied throughout the top 25 meters of the IODP ACEX 302 Hole 4C from the central Arctic Ocean at a resolution varying from 5cm (at the top of the record) to 10cm. Planktonic foraminifera occur in high absolute abundances only in the uppermost fifty centimetres and are dominated by the taxa Neogloboquadrina pachyderma. Except for a few intermittent layers below this level,most samples are barren of calcareous microfossils.Within the topmost sediments, Neogloboquadrina pachyderma specimens present large morphological variability in the shape and number of chambers in the finalwhorl, chamber sphericity, size, and coiling direction. Five morphotypeswere identified among the sinistral (sin.) population (Nps-1 to Nps-5), including a small form (Nps-5) that is similar to a non-encrusted normal form also previously identified in the modern Arctic Ocean watermasses. Twenty five percent of the sinistral population is made up by large specimens (Nps-2, 3, 4), with a maximal mean diameter larger than 250µm. Following observations made in peri-Arctic seas (Hillaire-Marcel et al. 2004, doi:10.1016/j.quascirev.2003.08.006), we propose that occurrence of these large-sized specimens of N. pachyderma (sin.) in the central Arctic Ocean sediments could sign North Atlantic water sub-surface penetration.