Near-Earth asteroid binaries in close encounters with the Earth

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

Effective field theory methods to model compact binaries

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

Search for gravitational radiation from intermediate mass black hole binaries in data from the second LIGO-Virgo joint science run

This paper reports on an unmodeled, all-sky search for gravitational waves from merging intermediate mass black hole binaries (IMBHB). The search was performed on data from the second joint science run of the LIGO and Virgo detectors (July 2009-October 2010) and was sensitive to IMBHBs with a range up to similar to 200 Mpc, averaged over the possible sky positions and inclinations of the binaries with respect to the line of sight. No significant candidate was found. Upper limits on the coalescence-rate density of nonspinning IMBHBs with total masses between 100 and 450 M-circle dot and mass ratios between 0.25 and 1 were placed by combining this analysis with an analogous search performed on data from the first LIGO-Virgo joint science run (November 2005-October 2007). The most stringent limit was set for systems consisting of two 88 M-circle dot black holes and is equal to 0.12 Mpc(-3) Myr(-1) at the 90% confidence level. This paper also presents the first estimate, for the case of an unmodeled analysis, of the impact on the search range of IMBHB spin configurations: the visible volume for IMBHBs with nonspinning components is roughly doubled for a population of IMBHBs with spins aligned with the binary's orbital angular momentum and uniformly distributed in the dimensionless spin parameter up to 0.8, whereas an analogous population with antialigned spins decreases the visible volume by similar to 20%.

Application of effective theory and Grassmann variables to model compact binaries with spin

Pós-graduação em Física - IFT

Mean motion resonances and the stability of a circumbinary disk in a triple stellar system

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Travestilidades nômades: a explosão dos binarismos e a emergência queering

Apresentamos neste artigo algumas problematizações a respeito da expressão travesti, que, não se apoiando em um modelo único de referência sexual e de gênero para sua efetivação, nos permitiria falar em processos de 'travestilização'. Esses processos se constituem através de dispositivos em que lineamentos duros, flexíveis e de fuga participam da criação de seus corpos, desejos e prazeres, transitando entre efeitos-consequências de discursos normativos e singularizadores. Sua circulação no mundo coloca em xeque as matrizes binárias heteronormativas do sistema sexo/gênero/desejo, que se desmancham diante de modos de subjetivação orientados por potências subversivas criadoras de novos campos possíveis de existencialização. Nessa perspectiva, queremos mostrar que as expressões sexuais e de gêneros das travestis formulam novas questões a respeito dos modelos identitários vigentes, demonstrando que a coerência e a inteligibilidade impostas pelos códigos heteronormativos precisam ser urgentemente revistas, de modo a questionar a respeito da ordem social que apresenta o gênero associado ao sexo reprodutivo, para ressignificar as expressões sexuais, gendradas e subjetivas, em sua processualidade histórica que explode os binarismos, despreza os universais e desmancha o absolutismo da ideia de verdade, enraizados nos sistemas binários de pensamentos sedentários, fechados, universais e a-históricos.

Context-sensitive analysis of obfuscated x86 executables

A method for context-sensitive analysis of binaries that may have obfuscated procedure call and return operations is presented. Such binaries may use operators to directly manipulate stack instead of using native call and ret instructions to achieve equivalent behavior. Since definition of context-sensitivity and algorithms for context-sensitive analysis have thus far been based on the specific semantics associated to procedure call and return operations, classic interprocedural analyses cannot be used reliably for analyzing programs in which these operations cannot be discerned. A new notion of context-sensitivity is introduced that is based on the state of the stack at any instruction. While changes in 'calling'-context are associated with transfer of control, and hence can be reasoned in terms of paths in an interprocedural control flow graph (ICFG), the same is not true of changes in 'stack'-context. An abstract interpretation based framework is developed to reason about stack-contexts and to derive analogues of call-strings based methods for the context-sensitive analysis using stack-context. The method presented is used to create a context-sensitive version of Venable et al.'s algorithm for detecting obfuscated calls. Experimental results show that the context-sensitive version of the algorithm generates more precise results and is also computationally more efficient than its context-insensitive counterpart. Copyright © 2010 ACM.

Context-sensitive analysis without calling-context

Since Sharir and Pnueli, algorithms for context-sensitivity have been defined in terms of 'valid' paths in an interprocedural flow graph. The definition of valid paths requires atomic call and ret statements, and encapsulated procedures. Thus, the resulting algorithms are not directly applicable when behavior similar to call and ret instructions may be realized using non-atomic statements, or when procedures do not have rigid boundaries, such as with programs in low level languages like assembly or RTL. We present a framework for context-sensitive analysis that requires neither atomic call and ret instructions, nor encapsulated procedures. The framework presented decouples the transfer of control semantics and the context manipulation semantics of statements. A new definition of context-sensitivity, called stack contexts, is developed. A stack context, which is defined using trace semantics, is more general than Sharir and Pnueli's interprocedural path based calling-context. An abstract interpretation based framework is developed to reason about stack-contexts and to derive analogues of calling-context based algorithms using stack-context. The framework presented is suitable for deriving algorithms for analyzing binary programs, such as malware, that employ obfuscations with the deliberate intent of defeating automated analysis. The framework is used to create a context-sensitive version of Venable et al.'s algorithm for analyzing x86 binaries without requiring that a binary conforms to a standard compilation model for maintaining procedures, calls, and returns. Experimental results show that a context-sensitive analysis using stack-context performs just as well for programs where the use of Sharir and Pnueli's calling-context produces correct approximations. However, if those programs are transformed to use call obfuscations, a contextsensitive analysis using stack-context still provides the same, correct results and without any additional overhead. © Springer Science+Business Media, LLC 2011.

Context-sensitive analysis of x86 obfuscated executables

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Bias na Representação de Assunto: Uma Discussão de Oposições Binárias nos Functional Requirements for Subject Authority Data (FRSAD)

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

Measuring the Spin of Black Holes in Binary Systems Using Gravitational Waves

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

A potência do cyborg no agenciamento de modos de subjetivação pós-identitários: conexões parciais entre arte, psicologia e gênero

In line with a psychology more attached to the becoming [devenir] rather than tothe essence, the goal of this paper is to ground the importance of understandingsubjectivity as a process, mainly when regarding our current discussions aboutidentity and gender. After that, we do some linkage between art and psychology. Forus, art is understood as a powerfulmanner to encourage modes of subjectivation thathave difference as an inherited relation. Lastly, we draw our attention upon somefragments of the contemporaneous artist, Mathew Barney's work-of-art (specially,Cremaster), to see how it runs through the binaries of gender boundaries andlaunches post-identity lines of subjectivation.

Planet formation in a triple stellar system: implications of the third star's orbital inclination

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