This thesis is on the study of the characterization of interfaces and surfaces of high-k stacks for the future microelectronics. The changes of the high-k stacks during thermal processing and its mechanism have been experimentally investigated by high-resolution Rutherford Backscattering Spectrometry (HRBS) in combination with isotope tracing. The experimental results are consistent with the theoretical prediction that the silicon will be emitted outward to release the stress which is induced by the interface Si oxidation. Then, we studied the potential method, oxygen-gettering by Ti overlayer, for controlling the interface SiO2 thickness. Furthermore, we proposed a Time-Of-Flight (TOF) detector system for application on crystallographic analysis. TOF-RBS system is capable to analyze the sample’s crystallographic and chemical information even at the near surface of the sample, which is strongly required by the future microelectronics industry. In this chapter, brief introduction to the high-k stacks and the outline of this thesis are described. / Kyoto University (京都大学) / 0048 / 新制・課程博士 / 博士(工学) / 甲第13814号 / 工博第2918号 / 新制||工||1431(附属図書館) / 26030 / UT51-2008-C730 / 京都大学大学院工学研究科マイクロエンジニアリング専攻 / (主査)教授 木村 健二, 教授 斧 髙一, 教授 立花 明知 / 学位規則第4条第1項該当

The enormous increase in device connectivity for data and telecom devices places significant challenges on the packet processing techniques used in embedded systems such as IP stacks. Therefore, the traditional packet processing software cannot handle the line rate packet flow even for the most cutting edge devices. A solution to this problem is to allow applications to directly receive packets without passing through the normal kernel stack and drivers i.e. interface directly with the hardware. Two such open source libraries for Linux are PF_RING and Netmap. In addition Freescale has a similar technology called USDPAA. In order to satisfy the first goal of this project, a detailed analysis and evaluation of PF_RING, Netmap and USDPAA has been conducted in order to determine how they compare in relation to a number of criteria such as functionality, support, performance, ease of use, software/ hardware dependencies and project stability etc. Secondly based on the earlier work, a design is proposed that can be used to build and port an application to run on Freescale DPAA based hardware (P4080) on top of USDPAA.

We develop a theory of unbounded derived categories of quasi-coherent sheaves on algebraic stacks. In particular, we show that these categories are compactly generated by perfect complexes for stacks that either have finite stabilizers or are local quotient stacks. We also extend Toën and Antieau–Gepner’s results on derived Azumaya algebras and compact generation of sheaves on linear categories from derived schemes to derived Deligne–Mumford stacks. These are all consequences of our main theorem: compact generation of a presheaf of triangulated categories on an algebraic stack is local for the quasi-finite flat topology.

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Au cours de ce travail, nous avons préparé des clips moléculaires efficaces à partir de dimères de cuivre(I) ou d'or(I) portant des ligands organophosphorés en tirant parti des interactions métallophiles. Dans un premier temps, un complexe de cuivre(I) portant des ligands bis(2-pyridyl)phospholes a été utilisé comme clip moléculaire pour organiser des systèmes pi monotopiques à fonction cyano et portant divers fragments pi-conjugués. Ces dimères formés par assemblage pis'auto-organisent à l'état solide en colonnes pi infinies. Dans un deuxième temps, un complexe d'or(I) portant un ligand biphosphole a été utilisé comme clip moléculaire pour organiser des unités éthynyl[6]helicenes en dimères. Ces dimères ont montré une augmentation des propriétés chiroptiques par rapport au ligand éthynyl[6]helicene libre. Dans un troisième temps, un complexe bimétallique de cuivre(I) portant des ligands 1,1-bis(diphénylphosphino)méthane (dppm) s'est révélé être un clip moléculaire efficace pour la conception d'architectures supramoléculaires auto-assemblées par réaction avec des cyanométallates. Ces dérivés supramoléculaires ont des topologies différentes et sont émissifs dans le domaine visible après excitation dans l'UV. Dans certains cas, ils ont montré des propriétés de luminescence thermochromique intéressantes. / In this work, we have prepared organophosphorated ligands based copper(I) or gold(I) dimers that act as efficient molecular clips thanks to metallophilic interactions. Firstly, a bimetallic copper(I) complex bearing bis(2-pyridyl)phosphole ligands was used as a molecular clip to organize monotopic cyano-capped pi-systems carrying various pi-conjugated fragments into self-assembled pi-stacked dimers. These dimers organized in the solid state within infinite columnar pi-stacks. Secondly, a bimetallic gold(I) complex bearing a biphosphole ligand was used as a molecular clip to organize ethynyl-capped [6]helicene moieties into self-assembled dimers. These dimers showed an enhancement of the chiroptical properties as compared to the free ethynyl[6]helicene ligand. Thirdly, a bimetallic copper(I) complex bearing 1,1-bis(diphenylphosphino)methane (dppm) ligands has revealed a powerful molecular clip to design self-assembled supramolecular architectures by reaction with different cyanometallates. These supramolecular derivatives have different topologies and are emissive in the visible spectrum upon UV excitation and in some cases they showed intriguing thermochromic luminescence properties.

L'espace des lacets lisses C(S^1,M) associé à une variété symplectique M se voit doté d'une structure (quasi-)symplectique induite par celle de M.Nous traiterons dans cette thèse d'un analogue algébrique de cet énoncé.Dans leur article, Kapranov et Vasserot ont introduit l'espace des lacets formels associé à un schéma. Il s'agit d'un analogue algébrique à l'espace des lacets lisses.Nous generalisons ici leur construction à des lacets de dimension supérieure. Nous associons à tout schéma X -- pas forcément lisse -- l'espace L^d(X) de ses lacets formels de dimension d.Nous démontrerons que ce dernier admet une structure de schéma (dérivé) de Tate : son espace tangent est de Tate, c'est-à-dire de dimension infinie mais suffisamment structuré pour se soumettre à la dualité.Nous définirons également l'espace B^d(X) des bulles de X, une variante de l'espace des lacets, et nous montrerons que le cas échéant, il hérite de la structure symplectique de X. Notons que ces résultats sont toujours valides dans des cas plus généraux : X peut être un champs d'Artin dérivé.Pour démontrer nos résultats, nous définirons ce que sont les objets de Tate dans une infinie-catégorie C stable et complète par idempotence.Nous prouverons au passage que le spectre de K-théorie non-connective de Tate(C) est équivalent à la suspension de celui de C, donnant une version infini-catégorique d'un résultat de Saito.Dans le dernier chapitre, nous traiterons d'un problème différent. Nous démontrerons l'existence d'une structure d'algèbre de Lie sur le tangent décalé de n'importe quel champ d'Artin dérivé X. Qui plus est, ce tangent agit sur tout quasi-cohérent E, l'action étant donnée par la classe d'Atiyah de E.Ces résultats sont par exemple valides dans le cas d'un schéma X sans hypothèse de lissité. / If M is a symplectic manifold then the space of smooth loops C(S^1,M) inherits of a quasi-symplectic form. We will focus in this thesis on an algebraic analogue of that result.In their article, Kapranov and Vasserot introduced and studied the formal loop space of a scheme X. It is an algebraic version of the space of smooth loops in a differentiable manifold.We generalize their construction to higher dimensional loops. To any scheme X -- not necessarily smooth -- we associate L^d(X), the space of loops of dimension d. We prove it has a structure of (derived) Tate scheme -- ie its tangent is a Tate module: it is infinite dimensional but behaves nicely enough regarding duality.We also define the bubble space B^d(X), a variation of the loop space.We prove that B^d(X) is endowed with a natural symplectic form as soon as X has one.To prove our results, we develop a theory of Tate objects in a stable infinity category C. We also prove that the non-connective K-theory of Tate(C) is the suspension of that of C, giving an infinity categorical version of a result of Saito.The last chapter is aimed at a different problem: we prove there the existence of a Lie structure on the tangent of a derived Artin stack X. Moreover, any quasi-coherent module E on X is endowed with an action of this tangent Lie algebra through the Atiyah class of E. This in particular applies to not necessarily smooth schemes X.

The world demand for energy is estimated to increase by up to 70% from 2016 to 2040. To meet this demand in a sustainable way, the power density of electric motors and generators can be increased by using superconducting materials. In particular, trapped field superconducting magnets, where the field is generated by a circulating persistent current in the sample, can create magnetic fields an order of magnitude higher than possible using conventional ferromagnets, thus increasing the power density of motors and generators. This is of great interest where added weight comes at a premium, such as for naval propulsion motors, wind generators and motors/generators for future electric aircraft. This work investigates the suitability of stacked tape layers of second generation high temperature superconductors (HTS), such as YBa2Cu3O7-x (YBCO) for trapped field applications. The present limits for trapped field magnitude have been determined, which provide a basis for the optimization of pulsed field magnetization techniques for in-situ magnetization in motors and generators. Trapped fields were increased by optimising the magnetic pulse sequence, using thermally conductive material to reduce temperature rise during pulse and changing the duration of the magnetic field pulse. Finite element method computer modelling was used to model and predict the behaviour of the trapped field magnets made of HTS tape with good agreement to experiment for both field cooling and pulsed field magnetisation. The models rely on critical current data for the HTS tape and its dependence on magnetic field and temperature. For this reason, a critical current testing facility was developed and constructed as a part of this work capable of measuring critical current up to 900 A, magnetic field of 1.5 T and down to temperatures of ~10 K in forced and dynamically controlled helium vapour flow. Lastly, first steps into scaling up by pulse magnetising an array of HTS tape stacks were made, allowing for larger overall trapped flux values. Such an array exhibits geometry, similar to what is going to be used in a functional motor prototype being developed in our research group (Applied Superconductivity and Cryoscience Group, ASCG). The work done culminated in the highest trapped field achieved to date using both field cooling (13.4 T between two stacks) and pulsed field magnetization (2.1 T above a single stack), for this type of trapped field magnet.

<div>Control-flow hijacking attacks allow adversaries to take over seemingly benign software, e.g., a web browser, and cause it to perform malicious actions, i.e., grant attackers a shell on</div><div>a system. Such control-flow hijacking attacks exploit a gap between high level language semantics and the machine language that they are compiled to. In particular, systems</div><div>software such as web browsers and servers are implemented in C/C++ which provide no runtime safety guarantees, leaving memory and type safety exclusively to programmers. Compilers are ideally situated to perform the required analysis and close the semantic gap between C/C++ and machine languages by adding instrumentation to enforce full or partial memory safety.</div><div><br></div><div><div>In unprotected C/C++, adversaries must be assumed to be able to control to the contents of any writeable memory location (arbitrary writes), and to read the contents of any readable memory location (arbitrary reads). Defenses against such attacks range from enforcing full memory safety to protecting only select information, normally code pointers to prevent control-flow hijacking attacks. We advance the state of the art for control-flow hijacking</div><div>defenses by improving the enforcement of full memory safety, as well as partial memory safety schemes for protecting code pointers.</div></div><div><br></div><div><div>We demonstrate a novel mechanism for enforcing full memory safety, which denies attackers both arbitrary reads and arbitrary writes at half the performance overhead of the</div><div>prior state of the art mechanism. Our mechanism relies on a novel metadata scheme for maintaining bounds information about memory objects. Further, we maintain the application</div><div>binary interface (ABI), support all C/C++ language features, and are mature enough to protect all of user space, and in particular libc.</div></div><div><br></div><div><div>Backwards control-flow transfers, i.e., returns, are a common target for attackers. In particular, return-oriented-programming (ROP) is a code-reuse attack technique built around corrupting return addresses. Shadow stacks prevent ROP attacks by providing partial memory safety for programs, namely integrity protecting the return address. We provide a full taxonomy of shadow stack designs, including two previously unexplored designs, and demonstrate that with compiler support shadow stacks can be deployed in practice. Further we examine the state of hardware support for integrity protected memory regions within a process’ address space. Control-Flow Integrity (CFI) is a popular technique for securing forward edges, e.g., indirect function calls, from being used for control-flow hijacking attacks. CFI is a form of partial memory safety that provides weak integrity for function pointers by restricting them to a statically determined set of values based on the program’s control-flow graph. We survey existing techniques, and quantify the protection they provide on a per callsite basis.</div><div>Building off this work, we propose a new security policy, Object Type Integrity, which provides full integrity protection for virtual table pointers on a per object basis for C++</div><div>polymorphic objects.</div></div>

This thesis concerns the study of chiral algebras over schemes of arbitrary dimension n. In Chapter I, we construct a chiral algebra over each smooth variety X of dimension n. We do this via the Hilbert scheme of points of X, which we use to build a factorisation space over X. Linearising this space produces a factorisation algebra over X, and hence, by Koszul duality, the desired chiral algebra. We begin the chapter with an overview of the theory of factorisation and chiral algebras, before introducing our main constructions. We compute the chiral homology of our factorisation algebra, and show that the D-modules underlying the corresponding chiral algebras form a universal D-module of dimension n. In Chapter II, we discuss the theory of universal D-modules and OO- modules more generally. We show that universal modules are equivalent to sheaves on certain stacks of étale germs of n-dimensional varieties. Furthermore, we identify these stacks with the classifying stacks of groups of automorphisms of the n-dimensional disc, and hence obtain an equivalence between the categories of universal modules and the representation categories of these groups. We also define categories of convergent universal modules and study them from the perspectives of the stacks of étale germs and the representation theory of the automorphism groups.

Le premier chapitre montre par des méthodes toriques ($G-$graphes) que pour tout entier positif $n$, le quotient de l'espace affine à $n$ dimensions par le groupe cyclique $G_n$ d'ordre $2^n-1$ admet le $G_n$-schema de Hilbert comme résolution lisse crepante. Le deuxième chapitre contient des résultats sur les champs algébriques (construction du champ algébrique lisse associé à une log-paire). Le troisième chapitre montre l'équivalence entre la catégorie dérivée bornée des faisceaux cohérents $G_n-$équivariants sur l'espace affine et celle des faisceaux cohérents sur la résolution $G_n-$Hilb. Chapitre 4 donne une réalisation géométrique de la conjecture de Broué via la correspondance de McKay. L'annexe contient des résultats sur les groupes trihédraux, y compris un programme magma.