832 resultados para Guarantees
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A procura de contra-exemplos é provavelmente a fase mais importante do raciocí - nio dedutivo, uma vez que visa garantir a validade da conclusão. A explicação mais difundida para a diminuta procura de contra-exemplos é a capacidade limitada da memória de trabalho (Markovits & Barrouillet 2002; De Neys, Schaeken & d’Ydewalle, 2002; 2003; 2005a; 2005b) o que não parece ser suficiente para explicar a pouca iniciativa dos sujeitos em utilizarem a procura de contra-exemplos como estratégia de verificação (Oakhill, & Johnson-Laird, 1985). No presente trabalho testou-se a hipótese de que a necessidade de cognição dos sujeitos (Cacioppo & Petty, 1982) tem influência no processo de recuperação de contra-exemplos, para condicionais causais, de modo aprofundar o conhecimento das razões que levam a que os sujeitos procurem tão poucos contra-exemplos durante o raciocínio dedutivo (Oakhill, & Johnson-Laird, 1985; Johnson-laird, 2006). Para o efeito, um total de 60 participantes (15 alunos do mestrado integrado em psicologia, 15 alunos de doutoramento, 15 operários fabris e 15 empregados de mesa) realizou 3 tarefas: escala Necessidade de Cognição (Silva & Garcia-Marques, 2006), uma tarefa de raciocínio e uma tarefa para avaliar a capacidade da memória de trabalho (Guerreiro, Quelhas & Garcia-Madruga, 2006). Os resultados indicam que o processo de recuperação de contra-exemplos é influenciado pela necessidade de cognição e que esta influência além de significativa é superior à influência da capacidade da memória de trabalho.
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The big data era has dramatically transformed our lives; however, security incidents such as data breaches can put sensitive data (e.g. photos, identities, genomes) at risk. To protect users' data privacy, there is a growing interest in building secure cloud computing systems, which keep sensitive data inputs hidden, even from computation providers. Conceptually, secure cloud computing systems leverage cryptographic techniques (e.g., secure multiparty computation) and trusted hardware (e.g. secure processors) to instantiate a “secure” abstract machine consisting of a CPU and encrypted memory, so that an adversary cannot learn information through either the computation within the CPU or the data in the memory. Unfortunately, evidence has shown that side channels (e.g. memory accesses, timing, and termination) in such a “secure” abstract machine may potentially leak highly sensitive information, including cryptographic keys that form the root of trust for the secure systems. This thesis broadly expands the investigation of a research direction called trace oblivious computation, where programming language techniques are employed to prevent side channel information leakage. We demonstrate the feasibility of trace oblivious computation, by formalizing and building several systems, including GhostRider, which is a hardware-software co-design to provide a hardware-based trace oblivious computing solution, SCVM, which is an automatic RAM-model secure computation system, and ObliVM, which is a programming framework to facilitate programmers to develop applications. All of these systems enjoy formal security guarantees while demonstrating a better performance than prior systems, by one to several orders of magnitude.
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The past several years have seen the surprising and rapid rise of Bitcoin and other “cryptocurrencies.” These are decentralized peer-to-peer networks that allow users to transmit money, tocompose financial instruments, and to enforce contracts between mutually distrusting peers, andthat show great promise as a foundation for financial infrastructure that is more robust, efficientand equitable than ours today. However, it is difficult to reason about the security of cryptocurrencies. Bitcoin is a complex system, comprising many intricate and subtly-interacting protocol layers. At each layer it features design innovations that (prior to our work) have not undergone any rigorous analysis. Compounding the challenge, Bitcoin is but one of hundreds of competing cryptocurrencies in an ecosystem that is constantly evolving. The goal of this thesis is to formally reason about the security of cryptocurrencies, reining in their complexity, and providing well-defined and justified statements of their guarantees. We provide a formal specification and construction for each layer of an abstract cryptocurrency protocol, and prove that our constructions satisfy their specifications. The contributions of this thesis are centered around two new abstractions: “scratch-off puzzles,” and the “blockchain functionality” model. Scratch-off puzzles are a generalization of the Bitcoin “mining” algorithm, its most iconic and novel design feature. We show how to provide secure upgrades to a cryptocurrency by instantiating the protocol with alternative puzzle schemes. We construct secure puzzles that address important and well-known challenges facing Bitcoin today, including wasted energy and dangerous coalitions. The blockchain functionality is a general-purpose model of a cryptocurrency rooted in the “Universal Composability” cryptography theory. We use this model to express a wide range of applications, including transparent “smart contracts” (like those featured in Bitcoin and Ethereum), and also privacy-preserving applications like sealed-bid auctions. We also construct a new protocol compiler, called Hawk, which translates user-provided specifications into privacy-preserving protocols based on zero-knowledge proofs.
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La ambigüedad y carencias de la regulación sobre internamientos no voluntarios por razón de trastorno psíquico, unidas a la declaración de inconstitucionalidad que afecta a algunas de sus disposiciones por carecer del debido rango legal, exigen la elaboración de una normativa completa y bien estructurada de la materia. La reciente STC 141/2012, de 2 de julio, enjuicia por primera vez un caso de internamiento psiquiátrico urgente desde la óptica del derecho fundamental a la libertad personal, y el TC aprovecha la coyuntura para desarrollar minuciosamente las garantías que han de respetarse en tales casos con el fin de evitar vulneraciones arbitrarias del mismo. Este trabajo analiza la novedosa doctrina que sienta el TC en dicha sentencia.
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Dissertação de Mestrado apresentada ao Instituto Superior de Psicologia Aplicada para obtenção de grau de Mestre na especialidade de Psicologia Clínica.
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Los ciudadanos que en cualquier momento se ven involucrados en un proceso judicial deben conocer cómo se van a sustanciar y resolver sus causas, facilitándose mediante el sistema oral, brindando a los usuarios mayor confianza en la administración de justicia, que desempeña un rol trascendental e importante dentro del desarrollo de una sociedad. Las partes procesales buscan que sus pretensiones se vean reflejadas en una sentencia justa, considerando al Ecuador como un estado de derechos y de justicia garantizado en nuestra Carta Magna. Mediante esta monografía se pretende analizar la aplicación de la oralidad en el Código Orgánico General de Procesos. Revisando brevemente los antecedentes históricos: Egipto, Grecia, Roma hasta la actualidad, un análisis comparativo entre el sistema oral y escrito, pensamientos de autores a favor y en contra del sistema oral. Seanalizará la legislación en el ámbito nacional haciendo referencia a la Constitución del Ecuador, al Código Orgánico General de Procesos y al Código Orgánico de la Función Judicial, considerando a los principios del debido proceso. Se plasmará la opinión de juristas y profesionales de nuestro medio. Finalizando con las conclusiones de este trabajo. Ecuador como país, debe aprender de las experiencias pasadas y aprovecharlas adaptando la administración de justicia a las necesidades de nuestra colectividad, el sistema escrito no ha logrado solucionar satisfactoriamente los retos de la sociedad actual por ello ha sido sustituido y esperemos hayamos tomado el camino correcto.
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Reconfigurable HW can be used to build a hardware multitasking system where tasks can be assigned to the reconfigurable HW at run-time according to the requirements of the running applications. Normally the execution in this kind of systems is controlled by an embedded processor. In these systems tasks are frequently represented as subtask graphs, where a subtask is the basic scheduling unit that can be assigned to a reconfigurable HW. In order to control the execution of these tasks, the processor must manage at run-time complex data structures, like graphs or linked list, which may generate significant execution-time penalties. In addition, HW/SW communications are frequently a system bottleneck. Hence, it is very interesting to find a way to reduce the run-time SW computations and the HW/SW communications. To this end we have developed a HW execution manager that controls the execution of subtask graphs over a set of reconfigurable units. This manager receives as input a subtask graph coupled to a subtask schedule, and guarantees its proper execution. In addition it includes support to reduce the execution-time overhead due to reconfigurations. With this HW support the execution of task graphs can be managed efficiently generating only very small run-time penalties.
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Part 17: Risk Analysis
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Wireless power transfer (WPT) and radio frequency (RF)-based energy har- vesting arouses a new wireless network paradigm termed as wireless powered com- munication network (WPCN), where some energy-constrained nodes are enabled to harvest energy from the RF signals transferred by other energy-sufficient nodes to support the communication operations in the network, which brings a promising approach for future energy-constrained wireless network design. In this paper, we focus on the optimal WPCN design. We consider a net- work composed of two communication groups, where the first group has sufficient power supply but no available bandwidth, and the second group has licensed band- width but very limited power to perform required information transmission. For such a system, we introduce the power and bandwidth cooperation between the two groups so that both group can accomplish their expected information delivering tasks. Multiple antennas are employed at the hybrid access point (H-AP) to en- hance both energy and information transfer efficiency and the cooperative relaying is employed to help the power-limited group to enhance its information transmission throughput. Compared with existing works, cooperative relaying, time assignment, power allocation, and energy beamforming are jointly designed in a single system. Firstly, we propose a cooperative transmission protocol for the considered system, where group 1 transmits some power to group 2 to help group 2 with information transmission and then group 2 gives some bandwidth to group 1 in return. Sec- ondly, to explore the information transmission performance limit of the system, we formulate two optimization problems to maximize the system weighted sum rate by jointly optimizing the time assignment, power allocation, and energy beamforming under two different power constraints, i.e., the fixed power constraint and the aver- age power constraint, respectively. In order to make the cooperation between the two groups meaningful and guarantee the quality of service (QoS) requirements of both groups, the minimal required data rates of the two groups are considered as constraints for the optimal system design. As both problems are non-convex and have no known solutions, we solve it by using proper variable substitutions and the semi-definite relaxation (SDR). We theoretically prove that our proposed solution method can guarantee to find the global optimal solution. Thirdly, consider that the WPCN has promising application potentials in future energy-constrained net- works, e.g., wireless sensor network (WSN), wireless body area network (WBAN) and Internet of Things (IoT), where the power consumption is very critical. We investigate the minimal power consumption optimal design for the considered co- operation WPCN. For this, we formulate an optimization problem to minimize the total consumed power by jointly optimizing the time assignment, power allocation, and energy beamforming under required data rate constraints. As the problem is also non-convex and has no known solutions, we solve it by using some variable substitutions and the SDR method. We also theoretically prove that our proposed solution method for the minimal power consumption design guarantees the global optimal solution. Extensive experimental results are provided to discuss the system performance behaviors, which provide some useful insights for future WPCN design. It shows that the average power constrained system achieves higher weighted sum rate than the fixed power constrained system. Besides, it also shows that in such a WPCN, relay should be placed closer to the multi-antenna H-AP to achieve higher weighted sum rate and consume lower total power.
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Turkey is a non-nuclear member of a nuclear alliance in a region where nuclear proliferation is of particular concern. As the only North Atlantic Treaty Organization (NATO) member that has a border with the Middle East, Turkish officials argue that Turkey cannot solely rely on NATO guarantees in addressing the regional security challenges. However, Turkey has not been able to formulate a security policy that reconciles its quest for independence, its NATO membership, the bilateral relationship with the United States, and regional engagement in the Middle East. This dissertation assesses the strategic implications of Turkey’s perceptions of the U.S./NATO nuclear and conventional deterrence on nuclear issues. It explores three case studies by the process tracing of Turkish policymakers’ nuclear-related decisions on U.S. tactical nuclear weapons deployed in Europe, national air and missile defense, and Iran’s nuclear program. The study finds that the principles of Turkish security policymaking do not incorporate a fundamentally different reasoning on nuclear issues than conventional deterrence. Nuclear weapons and their delivery systems do not have a defining role in Turkish security and defense strategy. The decisions are mainly guided by non-nuclear considerations such as Alliance politics, modernization of the domestic defense industry, and regional influence. The dissertation argues that Turkey could formulate more effective and less risky security policies on nuclear issues by emphasizing the cooperative security approaches within the NATO Alliance over confrontational measures. The findings of this dissertation reveal that a major transformation of Turkish security policymaking is required to end the crisis of confidence with NATO, redefinition of the strategic partnership with the US, and a more cautious approach toward the Middle East. The dissertation argues that Turkey should promote proactive measures to reduce, contain, and counter risks before they develop into real threats, as well as contribute to developing consensual confidence-building measures to reduce uncertainty.
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A presente investigação teve como objetivo analisar o carácter subsidiário e complementar dos serviços de segurança privada, face à atividade desenvolvida pelas forças e serviços de segurança. Centrada nos espetáculos desportivos, procurou mostrar de que forma se materializa a complementaridade e subsidiariedade entre serviços de segurança privada e as forças e serviços de segurança. Através de uma estratégia de investigação qualitativa, concretizada a partir de uma pesquisa documental e um inquérito por entrevista semiestruturada, cujos dados foram alvo de análise de conteúdo, pretendeu-se recolher informação que permita à GNR melhorar a sua atuação na segurança dos espetáculos desportivos. No âmbito da segurança interna, a segurança privada assume um papel fundamental no garante da segurança, a par das atividades desenvolvidas pelas forças e serviços de segurança. Nos espetáculos desportivos, esta relação simbiótica é evidente, sendo um claro exemplo de uma abordagem integrada a este direito fundamental. Conclui-se que a relação, prevista legalmente como complementar e subsidiária, entre serviços de segurança privada e forças e serviços de segurança, se materializa pela adoção e normalização de diversos mecanismos de coordenação e articulação, mas principalmente pela partilha de um fim último comum: a segurança de todos os cidadãos. Abstract: Inserted in the CEMC 2015-16, this work aims to analyze the alternative and complementary nature of private security services, due to the activity carried out by Police Forces. Focusing on sports events, this research sought to show how materializes complementarity and subsidiarity between private security services and Police forces. Through a qualitative research strategy, implemented from documental research and a survey by semi-structured interviews, whose data were subjected to content analysis, we intended to collect information to the GNR improve their performance in the safety of sports events. In the context of internal security, private agents play a key role in security guarantees, along with the activities carried out by security forces and services. In sports events, this symbiotic relationship is too obvious, being a clear example of an integrated approach to this fundamental right. It was concluded that the relationship provided legally as complementary and subsidiarity between private security companies and security forces and services, materializes the adoption and standardization of various mechanisms for coordination and articulation, but mostly by sharing an end last common: the safety of all citizens.
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Coprime and nested sampling are well known deterministic sampling techniques that operate at rates significantly lower than the Nyquist rate, and yet allow perfect reconstruction of the spectra of wide sense stationary signals. However, theoretical guarantees for these samplers assume ideal conditions such as synchronous sampling, and ability to perfectly compute statistical expectations. This thesis studies the performance of coprime and nested samplers in spatial and temporal domains, when these assumptions are violated. In spatial domain, the robustness of these samplers is studied by considering arrays with perturbed sensor locations (with unknown perturbations). Simplified expressions for the Fisher Information matrix for perturbed coprime and nested arrays are derived, which explicitly highlight the role of co-array. It is shown that even in presence of perturbations, it is possible to resolve $O(M^2)$ under appropriate conditions on the size of the grid. The assumption of small perturbations leads to a novel ``bi-affine" model in terms of source powers and perturbations. The redundancies in the co-array are then exploited to eliminate the nuisance perturbation variable, and reduce the bi-affine problem to a linear underdetermined (sparse) problem in source powers. This thesis also studies the robustness of coprime sampling to finite number of samples and sampling jitter, by analyzing their effects on the quality of the estimated autocorrelation sequence. A variety of bounds on the error introduced by such non ideal sampling schemes are computed by considering a statistical model for the perturbation. They indicate that coprime sampling leads to stable estimation of the autocorrelation sequence, in presence of small perturbations. Under appropriate assumptions on the distribution of WSS signals, sharp bounds on the estimation error are established which indicate that the error decays exponentially with the number of samples. The theoretical claims are supported by extensive numerical experiments.
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Tese de Doutoramento, Gestão da Inovação e do Território, Faculdade de Economia, Universidade do Algarve, 2016
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La Constitución de la República del Ecuador vigente desde el año 2008, reconoce y garantiza derechos para los ciudadanos domiciliados en el país, entre ellos trabajadores/as y servidoras y servidores públicos. En diciembre de 2015, la Asamblea Nacional del Ecuador, mediante el procedimiento de Enmienda Constitucional unificó el régimen laboral de las personas que prestan sus servicios laborales en las instituciones y organismos estatales, debiendo adecuarse la normativa legal y secundaria a esta modificación de la Carta Magna hasta junio de 2016. En el presente trabajo abordaremos en su primer capítulo antecedentes históricos del derecho al trabajo en general y la legislación histórica que ha regido en nuestro país. En el segundo capítulo nos centraremos en distinguir cuales son las características del régimen laboral público y del privado en Ecuador y realizaremos recomendaciones en relación a derechos individuales de los servidores públicos. En el tercer capítulo haremos referencia a los Convenios Internacionales de la OIT ratificados y no ratificados por nuestro país. En el cuarto capítulo estableceremos similitudes y diferencias entre las legislaciones regionales en razón del reconocimiento de derechos colectivos para servidores públicos. En el capítulo cinco detallaremos criterios doctrinarios sobre los derechos de ejercicio colectivo, es decir: huelga, convenio colectivo y sindicalización en el sector público para finalmente en el sexto y último capítulo dar recomendaciones para la inminente reforma a la Ley Orgánica de Servicio Público, LOSEP.
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Desde la vigencia de la Constitución del 2008, nuestro país evidencia una serie de cambios significativos, relacionados principalmente con las garantías constitucionales. En la presente monografía se ha realizado un estudio detallado de cada uno de estos mecanismos constitucionales, que garantizan una protección eficiente de los derechos reconocidos en el ordenamiento jurídico interno y en los instrumentos internacionales a favor de las personas. La presente investigación se divide en dos importantes secciones, que son las siguientes: Inicialmente, se presentan los avances en tema de garantías constitucionales establecidas en la Constitución de 2008, en relación a las garantías reguladas en el cuerpo político de 1998; se desarrolla además, un análisis de cada uno de estos mecanismos constitucionales, garantías normativas, institucionales, de políticas públicas, y jurisdiccionales, efectuando una referencia de las instituciones que abarca cada una de ellas.