158 research outputs found
FM carrier deviation measured by differential probability method
Differential probability FM system measures deviation of a carrier modulated by a complex signal. The peak-to-peak amplitude is measured and related to the frequency shift of the carrier signal. The deviation is described in terms of a probability as well as a peak value
Drift and its mediation in terrestrial orbits
The slow deformation of terrestrial orbits in the medium range, subject to
lunisolar resonances, is well approximated by a family of Hamiltonian flow with
degree-of-freedom. The action variables of the system may experience
chaotic variations and large drift that we may quantify. Using variational
chaos indicators, we compute high-resolution portraits of the action space.
Such refined meshes allow to reveal the existence of tori and structures
filling chaotic regions. Our elaborate computations allow us to isolate precise
initial conditions near specific zones of interest and study their asymptotic
behaviour in time. Borrowing classical techniques of phase- space
visualisation, we highlight how the drift is mediated by the complement of the
numerically detected KAM tori.Comment: 22 pages, 11 figures, 1 table, 52 references. Comments and feedbacks
greatly appreciated. This article is part of the Research Topic `The
Earth-Moon System as a Dynamical Laboratory', confer
https://www.frontiersin.org/research-topics/5819/the-earth-moon-system-as-a-dynamical-laborator
Lagrangian descriptors and their applications to deterministic chaos
We present our recent contributions to the theory of Lagrangian descriptors
for discriminating ordered and deterministic chaotic trajectories. The class of
Lagrangian Descriptors we are dealing with is based on the Euclidean length of
the orbit over a finite time window. The framework is free of tangent vector
dynamics and is valid for both discrete and continuous dynamical systems. We
review its last advancements and touch on how it illuminated recently Dvorak's
quantities based on maximal extent of trajectories' observables, as
traditionally computed in planetary dynamics.Comment: Submitted as part of the proceedings of the Complex Planetary Systems
II - Kalvi-IAU Symposium 382. 3 figures. Limited to 6 page
Vicarious Victimization: Examining the Effects of Witnessing Victimization While Incarcerated on Offender Reentry.
Witnessing victimization in prison is a relatively new area of research. Prison victimization research focuses on direct experiences of victimization and its attending consequences; however, studies have not focused on the vicarious victimization experiences of prisoners. Drawing from the prison victimization, witnessing/exposure to violence, and offender reentry literature, this study will investigate the link between witnessing victimization in prison and individual post-release outcomes. Using multivariate analyses, I examined the extent to which individuals witness victimization in prison and the effects of witnessing victimization on individual post-release outcomes using The Prison Experience and Reentry study, a longitudinal study of 1613 males residing in Ohio halfway houses. The findings suggest that a significant proportion of offenders witness victimization while incarcerated. Furthermore, witnessing victimization, particularly witnessing sexual victimization and stealing, was significantly related to post-release outcomes. Policy implications and directions for future research are discussed
Inmate Misconduct and Victimization: Investigating the Changes Over Time and If the Risk Factors are Invariant Across Age and Victim-Offender Status
Before the 1970, there were approximately 196,000 offenders housed in prisons (Cahalan & Parsons, 1986). Today, more than one million offenders are housed in prison (Carson & Anderson, 2016). The increase in the size of the prison population has been, in part, attributed to the shift towards determinate sentencing. The prison boom fueled research that aimed at how inmates adapt to the depriving nature of prisons. Despite the vast amount of research on misconduct and victimization, there are still some gaps in the literature. Few researchers have examined how these policy shifts may have affected inmate adaptation and behavior while incarcerated. Second, the increase in time served in prison has resulted in inmates aging in prison, resulting in an increasing number of older inmates (age 50 and older) in prisons. The prison experiences of older inmates are still an understudied area. Finally, the literature shows that misconduct and victimization share numerous risk factors, yet the overlap has not been explored within the prison context. The current dissertation aims to extend the prison literature by using data from the Survey of Inmates in State and Federal Correctional Facilities series. The main findings are (1) inmates admitted to prison before 1980 had the highest rates of misconduct, (2) age differences exist in the risk factors of victimization and misconduct, and (3) the victim-offender overlap exists in prisons and the established risk factors of misconduct and victimization explain who is at risk of being a victim only, offender only, or a victim-offender
From order to chaos in Earth satellite orbits
We consider Earth satellite orbits in the range of semi-major axes where the
perturbing effects of Earth's oblateness and lunisolar gravity are of
comparable order. This range covers the medium-Earth orbits (MEO) of the Global
Navigation Satellite Systems and the geosynchronous orbits (GEO) of the
communication satellites. We recall a secular and quadrupolar model, based on
the Milankovitch vector formulation of perturbation theory, which governs the
long-term orbital evolution subject to the predominant gravitational
interactions. We study the global dynamics of this two-and-a-half
degrees-of-freedom Hamiltonian system by means of the fast Lyapunov indicator
(FLI), used in a statistical sense. Specifically, we characterize the degree of
chaoticity of the action space using angle-averaged normalized FLI maps,
thereby overcoming the angle dependencies of the conventional stability maps.
Emphasis is placed upon the phase-space structures near secular resonances,
which are of first importance to the space debris community. We confirm and
quantify the transition from order to chaos in MEO, stemming from the critical
inclinations, and find that highly inclined GEO orbits are particularly
unstable. Despite their reputed normality, Earth satellite orbits can possess
an extraordinarily rich spectrum of dynamical behaviors, and, from a
mathematical perspective, have all the complications that make them very
interesting candidates for testing the modern tools of chaos theory.Comment: 30 pages, 9 figures. Accepted for publication in the Astronomical
Journa
Detection of separatrices and chaotic seas based on orbit amplitudes
The Maximum Eccentricity Method (MEM) is a standard tool for the analysis of
planetary systems and their stability. The method amounts to estimating the
maximal stretch of orbits over sampled domains of initial conditions. The
present paper leverages on the MEM to introduce a sharp detector of
separatrices and chaotic seas. After introducing the MEM analogue for
nearly-integrable action-angle Hamiltonians, i.e., diameters, we use
low-dimensional dynamical systems with multi-resonant modes and junctions,
supporting chaotic motions, to recognise the drivers of the diameter metric.
Once this is appreciated, we present a second-derivative based index measuring
the regularity of this application. This quantity turns to be a sensitive and
robust indicator to detect separatrices, resonant webs and chaotic seas. We
discuss practical applications of this framework in the context of -body
simulations for the planetary case affected by mean-motion resonances, and
demonstrate the ability of the index to distinguish minute structures of the
phase space, otherwise undetected with the original MEM.Comment: Under review at Celestial Mechanics and Dynamical Astronomy. 8
Figures, 59 references, 17 pages. Comments and feedback welcom
Slavery and feminism in the writings of Madame de Staël
Anne-Louise Germaine de Staël devoted her works to the idea of freedom, particularly for women and slaves. As an intellectual and a writer of the late eighteenth and early nineteenth centuries in France, she judged not only her community but its political regimes according to the principles of feminism and abolitionism. As a woman, she had only two possible ways to play a public role: to hold a salon like her mother, or to publish books. She did both, and through these acquired considerable influence. De Staël was a feminist whose work queries the subordination of women to men, and her strong liberal position led her to equate the condition of women with that of slaves. De Staël's liberalism was a product of the Enlightenment and early Romanticism. Although she never departed from the Enlightenment's principles, she displayed a more Romantic attitude when she promoted 'enthusiasm' and emotion, which were reflected in her art, politics and love life.
Feminism
De Staël's most important struggle was her fight for the rights of women to education and freedom of thought. She was a feminist who questioned the organisation of society and the place of women in it. During the French Revolution, despite claims advocating gender equality and social justice, the status of women regressed rapidly. Like her feminist contemporaries, she advocated that women ought to be judged by the same liberal code as men while she also praised the positive aspects of female gender roles. De Staël was a moderate feminist who celebrated the feminine. She believed that if educated women retained their traditional female values, they could play an effective role in society.
Slavery
The European slave trade peaked in the eighteenth century, and feminists were among those campaigning for its abolition. Probably initially influenced by her father's stand against slavery, de Staël fought against it in life and in many of her writings. She took a pragmatic and political position when she addressed the subject in her literature, when she supported the campaign of William Wilberforce, and the fight of the leader of the Haitian Revolution, Toussaint Louverture.
Intersection of Feminism and Slavery in Madame de Staël's Writings
There is a strong link between abolitionism and feminism in de Staël's work, as in the works of other turn of the nineteenth-century feminists. Feminism was closely related to abolitionism as married women, especially from the upper classes, could identify with slaves because they too lacked certain civil rights and were treated as property. While de Staël fought for women to be treated fairly, she also introduced the notion of 'enslavement' to strong emotions which was as distressing as the physical and cultural restrictions enforced on women, and could be used to reinforce those restrictions. In her novels and treatises, she demonstrates that to be in the throes of passion is destructive, causing a loss of autonomy, identity and self-control, the same predicament suffered by slaves.
While numerous biographers of Madame de Staël have noted the impact her work has had on a range of political, social and historical matters, few have considered the way her feminism and abolitionism interacted and intersected in her work. This study analyses de Staël's work in the context of her times and demonstrates that not only did she advocate passionately for abolitionism and feminism, but that she saw how the repression of women and enslavement of Africans were linked in the society of eighteenth and early nineteenth centuries France
Drift and Its Mediation in Terrestrial Orbits
The slow deformation of terrestrial orbits in the medium range, subject to lunisolar resonances, is well approximated by a family of Hamiltonian flow with 2.5 degree-of-freedom. The action variables of the system may experience chaotic variations and large drift that we may quantify. Using variational chaos indicators, we compute high-resolution portraits of the action space. Such refined meshes allow to reveal the existence of tori and structures filling chaotic regions. Our elaborate computations allow us to isolate precise initial conditions near specific zones of interest and study their asymptotic behaviour in time. Borrowing classical techniques of phase-space visualization, we highlight how the drift is mediated by the complement of the numerically detected KAM tori
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