972 resultados para Tor
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U of I Only
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Many existing encrypted Internet protocols leak information through packet sizes and timing. Though seemingly innocuous, prior work has shown that such leakage can be used to recover part or all of the plaintext being encrypted. The prevalence of encrypted protocols as the underpinning of such critical services as e-commerce, remote login, and anonymity networks and the increasing feasibility of attacks on these services represent a considerable risk to communications security. Existing mechanisms for preventing traffic analysis focus on re-routing and padding. These prevention techniques have considerable resource and overhead requirements. Furthermore, padding is easily detectable and, in some cases, can introduce its own vulnerabilities. To address these shortcomings, we propose embedding real traffic in synthetically generated encrypted cover traffic. Novel to our approach is our use of realistic network protocol behavior models to generate cover traffic. The observable traffic we generate also has the benefit of being indistinguishable from other real encrypted traffic further thwarting an adversary's ability to target attacks. In this dissertation, we introduce the design of a proxy system called TrafficMimic that implements realistic cover traffic tunneling and can be used alone or integrated with the Tor anonymity system. We describe the cover traffic generation process including the subtleties of implementing a secure traffic generator. We show that TrafficMimic cover traffic can fool a complex protocol classification attack with 91% of the accuracy of real traffic. TrafficMimic cover traffic is also not detected by a binary classification attack specifically designed to detect TrafficMimic. We evaluate the performance of tunneling with independent cover traffic models and find that they are comparable, and, in some cases, more efficient than generic constant-rate defenses. We then use simulation and analytic modeling to understand the performance of cover traffic tunneling more deeply. We find that we can take measurements from real or simulated traffic with no tunneling and use them to estimate parameters for an accurate analytic model of the performance impact of cover traffic tunneling. Once validated, we use this model to better understand how delay, bandwidth, tunnel slowdown, and stability affect cover traffic tunneling. Finally, we take the insights from our simulation study and develop several biasing techniques that we can use to match the cover traffic to the real traffic while simultaneously bounding external information leakage. We study these bias methods using simulation and evaluate their security using a Bayesian inference attack. We find that we can safely improve performance with biasing while preventing both traffic analysis and defense detection attacks. We then apply these biasing methods to the real TrafficMimic implementation and evaluate it on the Internet. We find that biasing can provide 3-5x improvement in bandwidth for bulk transfers and 2.5-9.5x speedup for Web browsing over tunneling without biasing.
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International audience
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Dissertação (mestrado)—Universidade de Brasília, Faculdade de Tecnologia, Departamento de Engenharia Florestal, 2016.
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The aim of study was to examine the effects of the world's most challenging mountain ultramarathon (Tor des Geants [TdG]) on running mechanics. Mechanical measurements were undertaken in male runners (n = 16) and a control group (n = 8) before (PRE), during (MID), and after (POST) the TdG. Contact (tc) and aerial (ta) times, step frequency (f), and running velocity (v) were sampled. Spring-mass parameters of peak vertical ground-reaction force (Fmax), vertical downward displacement of the center of mass (Deltaz), leg-length change (DeltaL), and vertical (kvert) and leg (kleg) stiffness were computed. Significant decreases were observed in runners between PRE and MID for ta (P < .001), Fmax (P < .001), Deltaz (P < .05), and kleg (P < .01). In contrast, f significantly increased (P < .05) between PRE and MID-TdG. No further changes were observed at POST for any of those variables, with the exception of kleg, which went back to PRE. During the TdG, experienced runners modified their running pattern and spring-mass behavior mainly during the first half. The current results suggest that these mechanical changes aim at minimizing the pain occurring in lower limbs mainly during the eccentric phases. One cannot rule out that this switch to a "safer" technique may also aim to anticipate further damages.
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La littérature suggère que le sommeil paradoxal joue un rôle dans l'intégration associative de la mémoire émotionnelle. De plus, les rêves en sommeil paradoxal, en particulier leur nature bizarre et émotionnelle, semblent refléter cette fonction associative et émotionnelle du sommeil paradoxal. La conséquence des cauchemars fréquents sur ce processus est inconnue, bien que le réveil provoqué par un cauchemar semble interférer avec les fonctions du sommeil paradoxal. Le premier objectif de cette thèse était de reproduire conceptuellement des recherches antérieures démontrant que le sommeil paradoxal permet un accès hyper-associatif à la mémoire. L'utilisation d'une sieste diurne nous a permis d'évaluer les effets du sommeil paradoxal, comparativement au sommeil lent et à l’éveil, sur la performance des participants à une tâche sémantique mesurant « associational breadth » (AB). Les résultats ont montré que seuls les sujets réveillés en sommeil paradoxal ont répondu avec des associations atypiques, ce qui suggère que le sommeil paradoxal est spécifique dans sa capacité à intégrer les traces de la mémoire émotionnelle (article 1). En outre, les rapports de rêve en sommeil paradoxal étaient plus bizarres que ceux en sommeil lent, et plus intenses émotionnellement ; ces attributs semblent refléter la nature associative et émotionnelle du sommeil paradoxal (article 2). Le deuxième objectif de la thèse était de préciser si et comment le traitement de la mémoire émotionnelle en sommeil paradoxal est altéré dans le Trouble de cauchemars fréquents (NM). En utilisant le même protocole, nos résultats ont montré que les participants NM avaient des résultats plus élevés avant une sieste, ce qui correspond aux observations antérieures voulant que les personnes souffrant de cauchemars soient plus créatives. Après le sommeil paradoxal, les deux groupes, NM et CTL, ont montré des changements similaires dans leur accès associatif, avec des résultats AB-négatif plus bas et AB-positif plus grands. Une semaine plus tard, seul les participants NM a maintenu ce changement dans leur réseau sémantique (article 3). Ces résultats suggèrent qu’au fil du temps, les cauchemars peuvent interférer avec l'intégration de la mémoire émotionnelle pendant le sommeil paradoxal. En ce qui concerne l'imagerie, les participants NM avaient plus de bizarrerie et plus d’émotion positive, mais pas négative, dans leurs rêveries (article 4). Ces attributs intensifiés suggèrent à nouveau que les participants NM sont plus imaginatifs et créatifs à l’éveil. Dans l'ensemble, les résultats confirment le rôle du sommeil paradoxal dans l'intégration associative de la mémoire émotionnelle. Cependant, nos résultats concernant le Trouble de cauchemars ne sont pas entièrement en accord avec les théories suggérant que les cauchemars sont dysfonctionnels. Le groupe NM a montré plus d’associativité émotionnelle, de même que plus d'imagerie positive et bizarre à l’éveil. Nous proposons donc une nouvelle théorie de sensibilité environnementale associée au Trouble de cauchemar, suggérant qu'une sensibilité accrue à une gamme de contextes environnementaux sous-tendrait les symptômes uniques et la richesse imaginative observés chez les personnes souffrant de cauchemars fréquents. Bien que davantage de recherches doivent être faites, il est possible que ces personnes puissent bénéficier e milieux favorables, et qu’elles puissent avoir un avantage adaptatif à l'égard de l'expression créative, ce qui est particulièrement pertinent lorsque l'on considère leur pronostic et les différents types de traitements.
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The Stock Identification Methods Working Group (SIMWG) worked by correspondence in 2016. The working group was chaired by Lisa Kerr (USA). The work plan for SIMWG in 2016 comprised four Terms of Reference (ToR), some of which are continuing goals for SIMWG: a ) Review recent advances in stock identification methods; b ) Build a reference database with updated information on known biological stocks for species of ICES interest; c ) Provide technical reviews and expert opinions on matters of stock identifica-tion, as requested by specific Working Groups and SCICOM; d ) Review and report on advances in mixed stock analysis, and assess their po-tential role in improving precision of stock assessment. ToR a) is an ongoing task of SIMWG in which we provide a comprehensive update on recent applications of stock identification techniques to ICES species of interest, summa-rize new approaches in stock identification, and novel combinations of existing applica-tions. ToR b) is a multi-annual ToR in which SIMWG has taking steps to build a reference data-base consisting of SIMWG reviews of issues of stock identity for ICES species. ToR c) is a key ongoing task by SIMWG in which we addresses specific requests by ICES working groups for technical advice on issues of stock identity. This year we provided advice on mackerel in the Northeast Atlantic as requested by WGWIDE. ToR d) is a multi-annual ToR that is focused on tracking developments in the application of mixed stock analysis and the integration of this information into assessment and management.
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Trabalho baseado no relatório para a disciplina “Sociologia das Novas Tecnologias de Informação” no âmbito do Mestrado Integrado de Engenharia e Gestão Industrial, da Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa em 2015-16. O trabalho foi orientado pelo Prof. António Brandão Moniz do Departamento de Ciências Sociais Aplicadas (DCSA) na mesma Faculdade.
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Objetivo: Analizar las variaciones en el proceso de confirmación diagnóstica entre unidades de cribado, las variaciones en los resultados de cada episodio y la relación entre las tasas de las diferentes pruebas de confirmación diagnóstica y las de detección de lesiones. Método: Estudio observacional de las variaciones de las tasas estandarizadas de pruebas diagnósticas y de detección de lesiones, en 34 unidades de cribado de los programas poblacionales de detección precoz de cáncer de mama, de tres comunidades autónomas, en el periodo de 2002 a 2011. Resultados: Las razones de variación entre los percentiles 25-75 en las tasas de realización de pruebas diagnósticas oscilaron entre 1,68 (recitaciones) y 3,39 (punción-aspiración con aguja fina). En las tasas de detección de lesiones benignas, carcinoma ductal in situ y cáncer invasivo fueron, respectivamente, 2,79, 1,99 y 1,36. Se encontró una relación positiva entre las tasas de realización de pruebas y las tasas de detección en punción-aspiración con aguja fina y lesiones benignas (R²: 0,53), punción-aspiración con aguja fina y carcinoma invasivo (R²: 0, 28), biopsias cerradas y lesiones benignas (R²: 0,64), biopsias cerradas y carcinoma ductal in situ (R²: 0,61), y biopsias cerradas y carcinoma invasivo (R²: 0,48). Conclusiones: Se observaron variaciones en la realización de pruebas invasivas entre las unidades de detección precoz de cáncer de mama de mayor magnitud que las de detección de lesiones. Las unidades con más pruebas de punción-aspiración con aguja fina tienen mayores tasas de detección de lesiones benignas, y las que realizan más biopsias cerradas detectan más lesiones benignas y cáncer.
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Dissertação de mest. em Gestão e Conservação da Natureza, Faculdade de Ciências do Mar e do Ambiente, Univ. do Algarve, 2003
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Fondo Margaritainés Restrepo
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A violência é um problema que perturba a sociedade e a saúde individual e cole-tiva. A violência contra as mulheres é uma forma específica de maus tratos. Tem conse-quências para as mulheres que diretamente a sofrem, com repercussões sociofamiliares, acarretando marcas, mágoas e prejuízo grave nas esferas bio-psico-sociais. O CHBM-EPE tem em curso um programa de atendimento a mulheres vítimas de violência. Tor-na-se necessário realizar a sua revisão e atualização. No projeto atual, através de recolha de dados junto de provedores e beneficiárias de cuidados realizou-se o diagnóstico de situação, descrevem-se ambas as perspetivas e propõem-se medidas de melhoramento. O relatório aqui apresentado consiste na descrição da intervenção realizada. Os resulta-dos serão tidos em conta na revisão do Programa do CHBM-EPE contra a violência doméstica. Pretende-se a melhoria da qualidade dos cuidados; ABSTRAT: Violence Against Women. Review of the Institutional Project of the Hospital Barreiro - Montijo EPE. Violence is a problem that disrupts society and the individual and collective health. Violence against women is a specific form of ill-treatment. It has consequences for the female figures who directly suffer with social-familial repercussions, leading brands, hurts and serious injuries in the bio-psycho-social spheres. The CHBM-EPE has an ongoing program of assistance to women victims of violence. It is necessary to carry out its review and update. The current project, through data collection from providers and recipients of care will describe both perspectives. In the current project, through data collection from providers and recipients of care there was the diagnosis of the sit-uation, describes both perspectives and are proposed improvement measures. The report presented here is the description of the intervention performed. The results will be taken into account in the review of CHBM-EPE Program against domestic violence. It is in-tended to improve the quality of care.