Orientador: Eliezer Rizzo de Oliveira / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Filosofia e Ciencias Humanas / Made available in DSpace on 2018-08-06T00:04:33Z (GMT). No. of bitstreams: 1 Fuccille_LuisAlexandre_D.pdf: 2009624 bytes, checksum: 7fb797e0c477c429ecbfece4c0c377b2 (MD5) Previous issue date: 2006 / Resumo: O propósito do presente trabalho é avaliar em que medida a reforma militar empreendida pelo governo Femando Henrique Cardoso (1995-2002), "imposta" por mudanças tanto endógenas quanto exógenas, pode ser vista como parte de um esforço majs amplo de redesenho do aparelho de Estado e de busca de uma subordinação militar ainda pendente no processo de transição pós-autoritarismo. A inovação introduzida pela instituição do Ministério da Defesa não é desprezível, podendo representar profundas alterações tanto de ordem política como diplomáticas, administrativas, estratégicas e operacionais, que necessitam seriamente ser avaliadas. Buscar compreender como a democracia entra como uma variável interveniente no desenho da defesa nacional no quadro pós-1985 via análise da criação do Ministério da Defesa é a tarefa que pretendemos levar a cabo nesta Tese, sem perder de vista que o controle civil pleno dos militares é condição necessária, ainda que insuficiente, àconsolidação eaprofundamento do regime democrático brasileiro / Abstract: The aim of this study is to analyze in what measure the military reform released by the Fernando Henrique Cardoso's government (1995-2002), "imposed" by endogenous and exogenous changes, may be understood as part of a bigger effort on redraw up the State structure and seek a military subordination still missed in the transition process post authoritarian era in Brazil. The innovation introduced by the creation of the Defense Ministry is not despicable, indeed it represents deep changes in ali spheres: political, diplomatic, management, strategic and operational, ali of them needed to be evaluated. In this study we intend also to analyze the creation of the Defense Ministry by trying to comprehend how democracy appears as an intervening actor in the National Defense's structure post-1985. We do this being sure not to forget that, in spite of not being itself sufficient, the complete civilian's military control is essential to the consolidation and deepen of the Brazilian emocratic regime / Doutorado / Doutor em Ciência Política

This thesis aims to define the differences between the concept of self-defense under the criminal law of the Czech Republic and the United States of America, to assess their practical implications and propose possible recommendations de lege ferenda for the Czech legislation. Within the United States, the thesis further distinguishes between the concept of self-defense under the common law and the so-called Model Criminal Code, which together with the common law represents one of the most important sources of US criminal law. The thesis first compares the differences between the Continental and Anglo-American legal system, from which the respective national legal systems derive. Next part of the thesis further characterizes the Czech and American legal system, especially with regard to the status of criminal law and the role of jurisprudence within it. Particular attention is paid to the division of US legal system into federal and state, and the related issues of the organization of the judiciary and the system of precedents between various judicial bodies. This part then further introduces the aforementioned Model Criminal Code, which presents a compilation of the views of high-profile experts in the field of criminal law regarding the ideal form of criminal substantive law in the United States....

M.Sc. (Biochemistry) / Lipopolysaccharide (LPS) is a complex lipoglycan that is found in the outer membrane of Gram-negative bacteria and is composed of three regions namely the fatty acid Lipid A, a core region of short oligosaccharide chains and an O-antigen region of polysaccharides. When LPS is recognized as a microbe-/pathogen-associated molecular pattern (M/PAMP), it not only induces an innate immune response in plants but also stimulates the development of defence responses such as the immediate release of reactive oxygen species/intermediates (ROS/I), pathogen-related (PR) gene expression and activation of the hypersensitive response (HR), resulting in stronger subsequent pathogen interactions. The identification and characterisation of the elusive LPS receptor/receptor complex in plants is thus of importance, since understanding the mechanism of perception and specific signal transduction pathways will clarify, and lead to the advancement of, basal resistance in plants in order to decrease crop plant losses due to pathogen attack. In mammals, LPS binds to a LPS binding protein (LBP) to form a LPS-LBP complex which is translocated to myeloid differentiation 2 (MD2) with the presence/absence of its co-receptor, a glycosylphosphatidylinositol (GPI)-linked protein, CD14. The interaction occurs on the host membrane and triggers an inflammatory defence response through the signalling cascade activated by the interaction with Toll-like receptor 4 (TLR4). A similar LPS-receptor interaction is, however, unknown in plants. To address the LPS perception mechanism in plants, biological binding studies with regard to concentration, incubation time and temperature, affinity, specificity and saturation were conducted in Arabidopsis thaliana protoplasts using LPS labeled with Alexa 488 hydrazide. Quantum dots (Qdots), which allow non-covalent hydrophobic labeling of LPS, were further also employed in similar Arabidopsis protoplast binding studies. These studies were conducted by fluorescence determination through the use of a BD FACS Aria flow cytometer. Although Alexa-labeling does not affect the biological activity in mammalian studies, the same cannot necessarily be said for plant systems, and hence Qdots were included to address this question. The conjugation of Qdots to LPS was confirmed by transmission electron microscopy (TEM) and results illustrated higher fluorescence values as compared to Alexa-LPS fluorescence analysis. Furthermore, inhibition of the perception process is also reported using Wortmannin and Brefeldin A as suitable endo- and exocytosis inhibitors. Affinity, specificity and saturability as well as the role of endo- and exocytosis inhibition in LPS binding to protoplasts was ultimately demonstrated by both fluorophores, with the use of Qdots as a label proving to be a more sensitive strategy in comparison to the conventional Alexa 488 hydrazide label.

Les études entreprises depuis une douzaine d'années indiquent que le monoxyde d'azote (NO) est un médiateur physiologique impliqué dans de nombreux processus chez les plantes, incluant la germination, le développement des racines, la fermeture des stomates ou encore la réponse adaptative aux stress biotiques et abiotiques. Malgré cet important panel de fonctions, les mécanismes sous-jacents aux effets du NO ont été peu appréhendés et restent pour l'essentiel énigmatiques. Le travail présenté dans ce manuscrit s'inscrit dans cette problématique et a consisté en l’identification et la caractérisation de protéines cibles du NO chez le tabac dans le contexte de stress biotiques et abiotiques. Nous avons démontré que la cryptogéine, un éliciteur des réactions de défense, induit la S-nitrosylation rapide et transitoire de plusieurs protéines dans des suspensions cellulaires de tabac. Après purification, une douzaine de ces protéines ont été identifiées via une analyse par spectrométrie de masse. Celles-ci incluent notamment une protéine chaperonne de la famille des AAA-ATPase nommée CDC48 (Cell Division Cycle 48). Cette dernière a fait l'objet d'une étude structure/fonction approfondie afin d'appréhender l'impact de sa S-nitrosylation. Après avoir vérifié que la protéine recombinante était S-nitrosylable in vitro, nous avons démontré que ce processus n'affecte pas la structure secondaire de la protéine mais induit des modifications locales de sa structure tertiaire et une inhibition de son activité ATPasique. Le résidu cystéine 526, localisé dans le second domaine ATPasique de la protéine, a été identifié comme site probable de S-nitrosylation. Cette localisation stratégique pourrait expliquer l'effet inhibiteur du NO sur l'activité enzymatique de CDC48. La dernière partie de ce travail a été centrée sur l'analyse des mécanismes par lesquels le NO active la protéine kinase NtOSAK (Nicotiana tabacum stress activated protein kinase) chez le tabac. Nous avons démontré que NtOSAK forme un complexe constitutif avec la glycéraldéhyde 3 phosphate deshydrogénase (GAPDH). En réponse à un stress salin, le NO promeut l'activation de NtOSAK via la phosphorylation de deux résidus serine localisés dans la boucle d'activation de l'enzyme. De plus, il induit une S-nitrosylation rapide de la GAPDH, ce processus n'affectant pas la formation du complexe. Notre hypothèse est que ce complexe constituerait une plateforme de signalisation régulée par le NO et pouvant recruter les protéines cibles de NtOSAK lors de la réponse au stress salin. / Studies conducted over the past ten years indicate that nitric oxide (NO) is a physiological mediator involved in many physiological processes in plants, including germination, root development, stomatal closure or responses against biotic or abiotic stresses. Despite this important range of functions, the mechanisms underlying the effects of NO in plants remain largely unknown. The present work aims at identifying and functionally characterizing NO target proteins in tobacco in the context of biotic and abiotic stresses. We demonstrated that cryptogein, an elicitor of defense responses, induces a rapid and transient S-nitrosylation of several proteins in tobacco cell suspensions. After purification, a dozen of these proteins have been identified through mass spectrometry analysis. These proteins include CDC48 (Cell Division Cycle 48), a chaperone-like protein belonging to the AAA-ATPase family. The regulation of CDC48 by NO was deeply investigated using a combination of structural and biochemical analyses. Once the in vitro S-nitrosylation of CDC48 was confirmed, we next demonstrated that this process does not affect the secondary structure of the protein but induces local changes in its tertiary structure together with an inhibition of its ATPase activity. The cysteine residue 526, located in the second ATPase domain of the protein, was identified as a probable S-nitrosylation site. This crucial localization may explain the inhibitory effect of NO on CDC48 enzymatic activity. The last part of this work was focused on the analysis of the mechanisms underlying the NO-dependent activation of the protein kinase NtOSAK (Nicotiana tabacum stress activated protein kinase) in tobacco. We demonstrated that NtOSAK forms a constitutive complex with glyceraldehyde 3-phosphate dehydrogenase (GAPDH). In response to salt stress, NO promotes the activation of NtOSAK via the phosphorylation of two serine residues located in the activation loop of the enzyme. Moreover, it induces a rapid S-nitrosylation of GAPDH. Interestingly, this latter process does not affect the complex formation. Our hypothesis is that once S-nitrosylated, GAPDH might act as a phosphorelay recruiting protein substrates for NtOSAK.

M.Sc. / Since plants are stationary, their immune systems have adapted to their environments to enable them to overcome or respond appropriately to various environmental, physical and physiological stresses that they may encounter by developing complicated defense mechanisms. The plant defense response activates complex biochemical and structural changes in plant cells. Heat stress per se, appears to be a priority stress response in plants, and increased disease susceptibility may be a result of this response. In this study, altered gene expression levels mediated by a heat treatment in Arabidopsis thaliana seedlings were analyzed. Seedlings were exposed to a heat stress of 42C for 30 minutes, followed by a 2.5 hour recovery period at 25ºC. RNA that was isolated from the heat stress treated plants as well as control plants (untreated) was used to perform suppression subtractive hybridization (SSH) in order to obtain a forward and a reverse DNA library. The forward SSH library represented the genes that were up-regulated due to the heat shock and the reverse SSH library represented the down-regulated genes. Sequenced clones from these libraries were BLAST against the A. thaliana genome using the Genbank database and the Accession numbers retrieved were then used for Bioinformatics analysis to obtain functionality of the genes found. The bioinformatics tools used were TAIR tools, DAG graphs and FatiGO and genes were categorized into the biological processes, molecular functions and cellular components. The TAIR tools and FatiGO were then used to analyze microarray data obtained for a similar study, in order to compare the genes identified with SSH. The genes coding for photosystem IID, serine-type peptidase, phospholipase D α, a S-locus protein kinase, regulator of chromosome condensation (RCC1) and Glucose-6-phosphate translocator are prominently up-regulated whilst other genes encoding photosystem I, plastocyanin-like mavicyanin, carbohydrate trans-membrane transporter MSS1, zinc finger C3HC4 ring family protein, ubiquitin conjugating enzyme 35 (UBC35) and integral membrane family proteins are significantly down-regulated. The FatiGO results helped to assign functionality to the genes that were found. For the SSH forward library, the cellular protein metabolic pathway was the most highly expressed term (19.21%), whereas in the microarray data, the term „positive regulation of response to stimulus‟ and membrane disassembly had a 100% expression. The reverse SSH data (down-regulation) found phosphate metabolic process as the most highly expressed term with an expression of 44.36% ix and the microarray data (negative fold-change) found the term photorespiration to be the most highly expressed with 93.54% expression. These high levels of negative expression indicate the down-regulation of these processes in the cell during heat shock. From these results it can be assumed that at the onset of a heat stress, the plant‟s immediate response is to activate pathways of regulation as a response to the stimulus as a self-protection mechanism, and repress other pathways such as photorespiration in order to preserve its energy such as ATP. These findings suggest that the plant is well equipped to overcome stress in its environment by activation/repression of specific organelles and pathways in the system, in order to maintain its equilibrium. Studies such as these can prove to be helpful to solve the interesting question of how a plant overcomes various environmental stresses in order to prevent disease susceptibility.

<div>Cellular networks are an indispensable part of a nation's critical infrastructure. They not only support functionality that are critical for our society as a whole (e.g., business, public-safety message dissemination) but also positively impact us at a more personal level by enabling applications that often improve our quality of life (e.g., navigation). Due to deployment constraints and backward compatibility issues, the various cellular protocol versions were not designed and deployed with a strong security and privacy focus. Because of their ubiquitous presence for connecting billions of users and use for critical applications, cellular networks are, however, lucrative attack targets of motivated and resourceful adversaries. </div><div><br></div><div></div><div>In this dissertation, we investigate the security and privacy of 4G LTE and 5G protocol designs and deployments. More precisely, we systematically identify design weaknesses and implementation oversights affecting the critical operations of the networks, and also design countermeasures to mitigate the identified vulnerabilities and attacks. Towards this goal, we developed a systematic model-based testing framework called LTEInspector. LTEInspector can be used to not only identify protocol design weaknesses but also deployment oversights. LTEInspector leverages the combined reasoning capabilities of a symbolic model checker and a cryptographic protocol verifier by combining them in a lazy fashion. We instantiated \system with three critical procedures (i.e., attach, detach, and paging) of 4G LTE. Our analysis uncovered 10 new exploitable vulnerabilities along with 9 prior attacks of 4G LTE all of which have been verified in a real testbed. Since identifying all classes of attacks with a unique framework like \system is nearly impossible, we show that it is possible to identify sophisticated security and privacy attacks by devising techniques specifically tailored for a particular protocol and by leveraging the findings of LTEInspector. As a case study, we analyzed the paging protocol of 4G LTE and the current version of 5G, and observed that by leveraging the findings from LTEInspector and other side-channel information and by using a probabilistic reasoning technique it is possible to mount sophisticated privacy attacks that can expose a victim device's coarse-grained location information and sensitive identifiers when the adversary is equipped only with the victim's phone number or other soft-identity (e.g., social networking profile). An analysis of LTEInspector's findings shows that the absence of broadcast authentication enables an adversary to mount a wide plethora of security and privacy attacks. We thus develop an attack-agnostic generic countermeasure that provides broadcast authentication without violating any common-sense deployment constraints. Finally, we design a practical countermeasure for mitigating the side-channel attacks in the paging procedure without breaking the backward compatibility.</div>

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Memory corruption attacks have existed in C and C++ for more than 30 years, and over the years many defenses have been proposed. In addition to that, a new class of attacks, Spectre, has emerged that abuse speculative execution to leak secrets and sensitive data through micro-architectural side channels. Many defenses have been proposed to mitigate Spectre as well. However, with every new defense a new attack emerges, and then a new defense is proposed. This is an ongoing cycle between attackers and defenders. There exists many defenses for many different attack avenues. However, many suffer from either practicality or effectiveness issues, and security researchers need to balance out their compromises. Recently, many hardware vendors, such as Intel and ARM, have realized the extent of the issue of memory corruption attacks and have developed hardware security mechanisms that can be utilized to defend against these attacks. ARM, in particular, has released a mechanism called Pointer Authentication in which its main intended use is to protect the integrity of pointers by generating a Pointer Authentication Code (PAC) using a cryptographic hash function, as a Message Authentication Code (MAC), and placing it on the top unused bits of a 64-bit pointer. Placing the PAC on the top unused bits of the pointer changes its semantics and the pointer cannot be used unless it is properly authenticated. Hardware security features such as PAC are merely mechanisms not full fledged defences, and their effectiveness and practicality depends on how they are being utililzed. Naive use of these defenses doesn't alleviate the issues that exist in many state-of-the-art software defenses. The design of the defense that utilizes these hardware security features needs to have practicality and effectiveness in mind. Having both practicality and effectiveness is now a possible reality with these new hardware security features. This dissertation describes utilizing hardware security features, namely ARM PAC, to build effective and practical defense mechanisms. This dissertation first describes my past work called PACTight, a PAC based defense mechanism that defends against control-flow hijack- ing attacks. PACTight defines three security properties of a pointer such that, if achieved, prevent pointers from being tampered with. They are: 1) unforgeability: A pointer p should always point to its legitimate object; 2) non-copyability: A pointer p can only be used when it is at its specific legitimate location; 3) non-dangling: A pointer p cannot be used after it has been freed. PACTight tightly seals pointers and guarantees that a sealed pointer cannot be forged, copied, or dangling. PACTight protects all sensitive pointers, which are code pointers and pointers that point to code pointers. This completely prevents control-flow hijacking attacks, all while having low performance overhead. In addition to that, this dissertation proposes Scope-Type Integrity (STI), a new defense policy that enforces pointers to conform to the programmer's intended manner, by utilizing scope, type, and permission information. STI collects information offline about the type, scope, and permission (read/write) of every pointer in the program. This information can then be used at runtime to ensure that pointers comply with their intended purpose. This allows STI to defeat advanced pointer attacks since these attacks typically violate either the scope, type, or permission. We present Runtime Scope-Type Integrity (RSTI). RSTI leverages ARM Pointer Authentication (PA) to generate Pointer Authentication Codes (PACs), based on the information from STI, and place these PACs at the top bits of the pointer. At runtime, the PACs are then checked to ensure pointer usage complies with STI. RSTI overcomes two drawbacks that were present in PACTight: 1) PACTight relied on a large external metadata for protection, whereas RSTI uses very little metadata. 2) PACTight only protected a subset of pointers, whereas RSTI protects all pointers in a program. RSTI has large coverage with relatively low overhead. Also, this dissertation proposes sPACtre, a new and novel defense mechanism that aims to prevent Spectre control-flow attacks on existing hardware. sPACtre is an ARM-based defense mechanism that prevents Spectre control-flow attacks by relying on ARM's Pointer Authentication hardware security feature, annotations added to the program on the secrets that need to be protected from leakage and a dynamic tag-based bounds checking mechanism for arrays. We show that sPACtre can defend against these attacks. We evaluate sPACtre on a variety of cryptographic libraries with several cryptographic algorithms, as well as a synthetic benchmark, and show that it is efficient and has low performance overhead Finally, this dissertation explains a new direction for utilizing hardware security features to protect energy harvesting devices from checkpoint-recovery errors and malicious attackers. / Doctor of Philosophy / In recent years, cyber-threats against computer systems have become more and more preva- lent. In spite of many recent advancements in defenses, these attacks are becoming more threatening. However, many of these defenses are not implemented in the real-world. This is due to their high performance overhead. This limited efficiency is not acceptable in the real-world. In addition to that, many of these defenses have limited coverage and do not cover a wide variety of attacks. This makes the performance tradeoff even less convincing. Thus, there is a need for effective and practical defenses that can cover a wide variety of attacks. This dissertation first provides a comprehensive overview of the current state-of-the-art and most dangerous attacks. More specifically, three types of attacks are examined. First, control-flow hijacking attacks, which are attacks that divert the proper execution of a pro- gram to a malicious execution. Second, data oriented attacks. These are attacks that leak sensitive data in a program. Third, Spectre attacks, which are attacks that rely on sup- posedly hidden processor features to leak sensitive data. These "hidden" features are not entirely hidden. This dissertation explains these attacks in detail and the corresponding state-of-the-art defenses that have been proposed by the security research community to mitigate them. This dissertation then discusses effective and practical defense mechanisms that can mitigate these attacks. The dissertation discusses past work, PACTight, as well as its contributions, RSTI and sPACtre, presenting the full design, threat model, implementation, security eval- uation and performance evaluation of each one of these mechanisms. The dissertation relies on insights derived from the nature of the attack and compiler techniques. A compiler is a tool that transforms human-written code into machine code that is understandable by the computer. The compiler can be modified and used to make programs more secure with compiler techniques. The past work, PACTight, is a defense mechanism that defends against the first type of attacks, control-flow hijacking attacks, by preventing an attacker from abusing specific code in the program to divert the program to a malicious execution. Then, this dissertation presents RSTI, a new defense mechanism that overcomes the limitations of PACTight and extends it to cover data oriented attacks and prevent attackers from leaking sensitive data from the program. In addition to that, this dissertation presents sPACtre, a novel defesnse mechanism that defends against Spectre attacks, and prevents an attacker from abusing a processor's hidden features. Finally, this dissertation briefly discusses a possible future direction to protect a different class of devices, referred to as energy-harvesting devices, from attackers.

<p dir="ltr">This research explores adversarial attacks on Graph Convolutional Transformer (GCT) models that utilize Electronic Health Record (EHR) data. As deep learning models become increasingly integral to healthcare, securing their robustness against adversarial threats is critical. This research assesses the susceptibility of GCT models to specific adversarial attacks, namely the Fast Gradient Sign Method (FGSM) and the Jacobian-based Saliency Map Attack (JSMA). It examines their effect on the model’s prediction of mortality and readmission. Through experiments conducted with the MIMIC-III and eICU datasets, the study finds that although the GCT model exhibits superior performance in processing EHR data under normal conditions, its accuracy drops when subjected to adversarial conditions—from an accuracy of 86% with test data to about 57% and an area under the curve (AUC) from 0.86 to 0.51. These findings averaged across both datasets and attack methods, underscore the urgent need for effective adversarial defense mechanisms in AI systems used in healthcare. This thesis contributes to the field by identifying vulnerabilities and suggesting various strategies to enhance the resilience of GCT models against adversarial manipulations.</p>