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Shelat, Abhi. "Études in non-interactive zero-knowledge." Thesis, Massachusetts Institute of Technology, 2005. http://hdl.handle.net/1721.1/35531.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, February 2006.<br>Includes bibliographical references (p. 72-76).<br>N a ZERO-KNOWLEDGE PROOF [GMR85], Prover interactively convinces Verifier that theorem 7r is true in such a way that (a) a corrupt Prover cannot convince Verifier of a false theorem and (b) a corrupt Verifier cannot "learn" anything other than the fact that r is true. In a NON-INTERACTIVE ZERO-KNOWLEDGE PROOF [BFM88], the Prover must do the above by sending only a single message to Verifier! To make this possible, Prover and Verifier are not tabula rasa, but rather born with some setup information. Much in the fashion of a musical TUDE, in this thesis, we explore several variations on the setup assumptions for non-interactive zero-knowledge in order to enjoy a richer understanding. Our labor brings forth * various unconditional characterizations of computational and statistical NIZK proofs, * new constructions that have practical applications to non-malleable encryption and CCAz encryption, * new constructions which form the building blocks of "fair" versions of interactive zero-knowledge and collusion-free multi-party computation protocols, * and conceptual contributions which underlie the recent works on how cryptography can be used to achieve equilibrium in game theory.<br>by Abhi Shelat.<br>Ph.D.
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González, Ulloa Alonso Emilio. "Efficient non-interactive zero-knowledge Proofs." Tesis, Universidad de Chile, 2017. http://repositorio.uchile.cl/handle/2250/144465.
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Doctor en Ciencias, Mención Computación<br>Non-Interactive Zero-Knowledge (NIZK) proofs, are proofs that yield nothing beyond their validity. As opposed to the interactive variant, NIZK proofs consist of only one message and are more suited for high-latency scenarios and for building inherently non- interactive schemes, like signatures or encryption.
With the advent of pairing-based cryptography many cryptosystems have been built using bilinear groups, that is, three abelian groups G1,G2,GT oforderqtogetherwithabilinear function e : G1 × G2 → GT . Statements related to pairing-based cryptographic schemes are naturally expressed as the satisfiability of equations over these groups and Zq.
The Groth-Sahai proof system, introduced by Groth and Sahai at Eurocrypt 2008, provides NIZK proofs for the satisfiability of equations over bilinear groups and over the integers modulo a prime q. Although Groth-Sahai proofs are quite efficient, they easily get expensive unless the statement is very simple. Specifically, proving satisfiability of m equations in n variables requires sending as commitments to the solutions Θ(n) elements of a bilinear group, and a proof that they satisfy the equations, which we simply call the proof, requiring additional Θ(m) group elements.
In this thesis we study how to construct aggregated proofs i.e. proofs of size independent of the number of equations for different types of equations and how to use them to build more efficient cryptographic schemes.
We show that linear equations admit aggregated proofs of size Θ(1). We then study the case of quadratic integer equations, more concretely the equation b(b − 1) = 0 which is the most useful type of quadratic integer equation, and construct an aggregated proof of size Θ(1). We use these results to build more efficient threshold Groth-Sahai proofs and more efficient ring signatures.
We also study a natural generalization of quadratic equations which we call set-membership proofs i.e. show that a variable belongs to some set. We first construct an aggregated proof of size Θ(t), where t is the set size, and of size Θ(logt) if the set is of the form [0,t − 1] ⊂ Zq. Then, we further improve the size of our set-membership proofs and construct aggregated proofs of size Θ(log t). We note that some cryptographic schemes can be naturally constructed as set-membership proofs, specifically we study the case of proofs of correctness of a shuffle and range proofs. Starting from set-membership proofs as a common building block, we build the shortest proofs for both proof systems.<br>Este trabajo ha sido parcialmente financiado por CONICYT, CONICYT-PCHA/Doctorado Nacional/2013-21130937
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Hegde, Suprabha Shreepad. "Analysis of Non-Interactive Zero Knowledge Proof." University of Cincinnati / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1535702372270471.
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Evans, P. Wynne M. "Non-zero temperature charmonium potentials from the lattice." Thesis, Swansea University, 2014. https://cronfa.swan.ac.uk/Record/cronfa42456.
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A reliable calculation of the charmonium potential at non-zero temperature from first principles is required as part of a wider effort to understand the phase transition of hadronic matter to quark-gluon plasma at high temperature. The interquark potential inside hot matter produced in heavy ion collisions can not be measured directly. Therefore the precise role of the intcrquark potential in quark-gluon plasma formation can currently only be determined through a reliable theoretical calculation. In this thesis charmonium potentials are obtained from dynamical lattice simulations of quantum chromodynamics by analysing correlators using two different approaches; i) conventional fitting - correlators are fitted in the conventional manner familiar from hadron spectroscopy on the lattice; ii) the HAL QCD time-dependent method - a novel technique borrowed from nuclear physics is used to derive an expression for the potential directly in terms of the correlators. Recent lattice QCD studies relevant to the charmonium potential fall into two categories: i) non-zero temperature studies of the static quark potential; ii) zero temperature studios with i)hysical charm masses. The results presented in this thesis are novel because they are from a study of the charnionium potential using physical charm masses at non-zero temperature. The charmonium potential obtained from conventional fitting is found to be temperature dependent, as the temperature increases, the potential flattens. However the method suffers from certain reliability issues. The time-dependent method is found to be more suitable than conventional fitting for studying the interquark potential at high temperature. Using the time-dependent method the charmonium potential between 0.76Tc and 1.09Tc is found to be temperature dependent. The result is reliable and shows the potential flattening as the temperature increases, which is consistent with the expectation that at high temperature the interquark potential becomes colour-Debye screened. Extracting the potential from temperatures higher than 1.09Tc would have led to unreliable results, but this limit is specific to the configurations used and not the method itself. The study shows that if configurations are generated with the time-dependent method in mind, then it can be used to extract the charmonium potential at temperatures higher than 1.09Tc.
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Brandt, Bastian Benjamin [Verfasser]. "Chiral properties of two-flavour QCD at zero and non-zero temperature / Bastian Benjamin Brandt." Mainz : Universitätsbibliothek Mainz, 2012. http://d-nb.info/102939122X/34.
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Steele, Nathan L. "Social utility in zero-sum and non-zero-sum games, with and without competing norms." [Bloomington, Ind.] : Indiana University, 2004. http://wwwlib.umi.com/dissertations/fullcit/3203864.
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Thesis (Ph.D.)--Indiana University, Dept. of Psychology, 2004.<br>Title from PDF t.p. (viewed Nov. 10, 2008). Source: Dissertation Abstracts International, Volume: 67-02, Section: B, page: 1209. Adviser: Jerome M. Chertkoff.
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Pindado, Zaira. "Pairing-based non-interactive zero-knowledge arguments and applications." Doctoral thesis, Universitat Pompeu Fabra, 2021. http://hdl.handle.net/10803/671270.
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Elliptic curves with a bilinear map, or pairing, have a rich algebraic structure that has been fundamental to develop practical Non-Interactive Zero-Knowledge (NIZK) proofs.
On the theoretical side, we explore how efficient can NIZK proofs be under weak complexity assumptions. Specifically, we reduce the cost of proofs of satisfiability of quadratic equations, we define a new commitment scheme that is compatible with other pairing-based NIZK arguments, and we construct a simulation-sound argument that results in a new a signature of knowledge with communication sublinear in the circuit size under standard assumptions.
Additionally, we study how to reduce the cost of verification in one of the most widely deployed NIZK arguments in practice.<br>Les corbes el·líptiques amb una aplicació bilineal, o pairing, tenen una estructura algebraica molt rica que ha sigut fonamental per desenvolupar proves de zero coneixement no interactives (NIZK).
En la banda teòrica, explorem quant eficients poden ser les proves NIZK sota hipòtesis de complexitat dèbils. Més concretament, reduïm el cost de les proves de satisfacció per equacions quadràtiques, definim un nou esquema de compromís que és compatible amb altres proves NIZK basades en pairings i construïm una prova que resulta en una nova signatura de coneixement amb una comunicació sublineal en la mida del circuit sota hipòtesis estàndards.
A més, estudiem com es redueix el cost de verificació en una de les proves NIZK més desenvolupades a la pràctica.
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Au, Tsz-Chiu. "Synthesis of strategies for non-zero-sum repeated games." College Park, Md.: University of Maryland, 2008. http://hdl.handle.net/1903/8629.
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Thesis (Ph. D.) -- University of Maryland, College Park, 2008.<br>Thesis research directed by: Dept. of Computer Science. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
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Roussellet, Guillaume. "Non-Negativity, Zero Lower Bound and Affine Interest Rate Models." Thesis, Paris 9, 2015. http://www.theses.fr/2015PA090012/document.
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Cette thèse présente plusieurs extensions relatives aux modèles affines positifs de taux d'intérêt. Un premier chapitre introduit les concepts reliés aux modélisations employées dans les chapitres suivants. Il détaille la définition de processus dits affines, et la construction de modèles de prix d'actifs obtenus par non-arbitrage. Le chapitre 2 propose une nouvelle méthode d’estimation et de filtrage pour les modèles espace-état linéaire-quadratiques. Le chapitre suivant applique cette méthode d’estimation à la modélisation d’écarts de taux interbancaires de la zone Euro, afin d’en décomposer les fluctuations liées au risque de défaut et de liquidité. Le chapitre 4 développe une nouvelle technique de création de processus affines multivariés à partir leurs contreparties univariées, sans imposer l’indépendance conditionnelle entre leurs composantes. Le dernier chapitre applique cette méthode et dérive un processus affine multivarié dont certaines composantes peuvent rester à zéro pendant des périodes prolongées. Incorporé dans un modèle de taux d’intérêt, ce processus permet de rendre compte efficacement des taux plancher à zéro<br>This thesis presents new developments in the literature of non-negative affine interest rate models. The first chapter is devoted to the introduction of the main mathematical tools used in the following chapters. In particular, it presents the so-called affine processes which are extensively employed in no-arbitrage interest rate models. Chapter 2 provides a new filtering and estimation method for linear-quadratic state-space models. This technique is exploited in the 3rd chapter to estimate a positive asset pricing model on the term structure of Euro area interbank spreads. This allows us to decompose the interbank risk into a default risk and a liquidity risk components. Chapter 4 proposes a new recursive method for building general multivariate affine processes from their univariate counterparts. In particular, our method does not impose the conditional independence between the different vector elements. We apply this technique in Chapter 5 to produce multivariate non-negative affine processes where some components can stay at zero for several periods. This process is exploited to build a term structure model consistent with the zero lower bound features
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Herron, Trevor P. "An Internship with the Zero Waste Alliance." Miami University / OhioLINK, 2005. http://rave.ohiolink.edu/etdc/view?acc_num=miami1114196877.
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Stevens, Irina. "Hereditary subalgebras of certain simple non real rank zero C§*-algebras." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape11/PQDD_0011/NQ41511.pdf.
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Neofytidis, Christoforos. "Non-zero degree maps between manifolds and groups presentable by products." Diss., Ludwig-Maximilians-Universität München, 2014. http://nbn-resolving.de/urn:nbn:de:bvb:19-172047.
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Spegal, Christopher S. "Unrelated Machine Scheduling with Deteriorating Jobs and Non-zero Ready Times." Ohio University / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou154672272196773.
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Bachman, David Charles. "A piecewise-linear theory of minimal surfaces of non-zero index /." Digital version accessible at:, 1999. http://wwwlib.umi.com/cr/utexas/main.
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Ramchandani, Nand-Lal. "Gas network optimisation using Nash equilibria derived from dynamic non-cooperative non-zero sum game theory." Thesis, University of Salford, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.261924.
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Dufner, Michael, Daniel Leising, and Jochen E. Gebauer. "Which Basic Rules Underlie Social Judgments?: Agency Follows a Zero-Sum Principle and Communion Follows a Non-Zero-Sum Principle." Sage, 2016. https://tud.qucosa.de/id/qucosa%3A35366.
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How are people who generally see others positively evaluated themselves? We propose that the answer to this question crucially hinges on the content domain: We hypothesize that Agency follows a “zero-sum principle” and therefore people who see others as high in Agency are perceived as low in Agency themselves. In contrast, we hypothesize that Communion follows a “non-zero-sum principle” and therefore people who see others as high in Communion are perceived as high in Communion themselves. We tested these hypotheses in a round-robin and a half-block study. Perceiving others as agentic was indeed linked to being perceived as low in Agency. To the contrary, perceiving others as communal was linked to being perceived as high in Communion, but only when people directly interacted with each other. These results help to clarify the nature of Agency and Communion and offer explanations for divergent findings in the literature.
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Ji, Kaiwen. "Exceptional Points Bifurcations and Zero Mode Lasing in Coupled Nanolaser Arrays." Electronic Thesis or Diss., université Paris-Saclay, 2024. http://www.theses.fr/2024UPASP167.
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La conservation de l'énergie façonne notre compréhension de la réalité. Néanmoins, ce principe peut être violé lorsqu’on considère un sous-système où l'énergie peut être échangée avec l'environnement externe. Un tel scénario physique peut être décrit par un Hamiltonien non-Hermitien présentant un spectre d'énergies complexes. L'étude des systèmes non-Hermitiens a connu des avancées remarquables depuis la découverte de la symétrie Parité-Temps (PT). Dans un tel système PT-symétrique, une singularité, appelée point exceptionnel (EP), a récemment suscité une attention considérable. Dans les systèmes optiques avec des composants gain/pertes, les points exceptionnels sont généralement définis sous le seuil de laser, spécifiquement dans le régime linéaire. En revanche, les dynamiques complexes liées aux points exceptionnels au-dessus du seuil laser n'ont pas encore été explorées. Dans la première partie de cette thèse, nous démontrons, à la fois théoriquement et expérimentalement, que les singularités EP dans des nanolasers couplés à cristal photonique en semi-conducteurs III-V peuvent être approchées au-dessus du seuil de laser, où elles deviennent des points de bifurcation non linéaires. Contrairement à l’idée préconçue selon laquelle le désaccord de cavité empêche la formation des EPs, nous montrons que, dans le contexte des systèmes lasers à semi-conducteurs, un tel désaccord est essentiel pour compenser le décalage de fréquence induit par les porteurs de charge. Le suivi continu du point exceptionnel en régime laser est rendu possible grâce à des expériences de photoluminescence avec une distribution spatiale contrôlable du faisceau de pompe. La deuxième partie de cette thèse aborde la mise en œuvre des mode zéro laser, qui attirent une attention considérable en raison de leur protection par la symétrie ou la topologie des réseaux : il s’agit du domaine des lasers topologiques. Le mode zéro en régime laser est d'abord démontré dans un système à trois nanocavités couplées (trimère) avec un pompage quasi égal sur les deux cavités extrêmes. Néanmoins, les modes zéro photoniques conventionnels, distingués par une émission en opposition de phase une distribution d'intensité confinée aux bords du système (edge modes), limitent considérablement leur applicabilité. Nous pallions à ces deux limitations par la technique d'ingénierie image-barrière d’une part, et la non-Hermiticité d’autre part. La première peut inverser le signe du couplage inter-cavité et générer un mode zéro en accord de phase; la seconde peut réaliser un mode zéro dans le volume (bulk) grâce à la restauration spontanée de la symétrie particule-trou non-Hermitienne. Enfin, nous explorons l'émergence à la fois des EP et du mode zéro dans une structure bidimensionnelle comprenant quatre nanolasers couplés disposés en anneau. La symétrie chirale non-Hermitienne génère un mode zéro à travers la coalescence des modes au niveau du EP, qui est ensuite stabilisée par une saturation non linéaire. De manière surprenante, les modes zéro au EP présentent une singularité de phase, à l’origine d’un vortex optique, observé expérimentalement à l'aide d’un interféromètre de Sagnac. Cette thèse se conclut par la présentation d'une application intrigante du mode zéro : le calcul optique. Nous démontrons, tant théoriquement qu’expérimentalement, que nos nanolasers peuvent exécuter des tâches de classification non triviales, qui s’avèrent difficiles pour une structure de calcul en réseau neuronal à une seule couche. Nous montrons que la couche complexe de nanolasers améliore considérablement la précision de calcul, notamment pour une faible dimensionalité des données d’entrée<br>Energy conservation shapes our understanding of reality. Nevertheless, this principle is no longer applicable when analyzing a subsystem where energy is exchanged with an external environment. Such a physical scenario can be described by a non-Hermitian Hamiltonian that exhibits a complex-energy spectrum. The investigation of non-Hermitian systems has undergone remarkable advancement since the discovery of Parity Time (PT) symmetry. In a PT symmetric system, a singularity, referred to as an exceptional point (EP), has recently attracted significant attention. In optical systems with gain/loss components, EPs are typically defined below the lasing threshold, specifically in the linear regime. Still, the complex dynamics related to EP above the lasing threshold are yet to be investigated. In the first part of this thesis, we both theoretically and experimentally demonstrate that EP singularities in coupled III-V semiconductor photonic crystal nanolasers can be accessed above the lasing threshold, where they become nonlinear branch points. Contrary to the common belief that the cavity detuning prohibits the formation of EPs, we point out that, in the context of the semiconductor laser system, such detuning is essential for compensating the carrier-induced frequency shift. Continuous tracking of the lasing EP is enabled by unbalanced pumping photoluminescence experiments. The second part of this thesis addresses the implementation of lasing zero modes, which receive considerable attention due to their symmetry or topology protected characteristics: a research domain called topological lasers. The lasing regime of the zero mode is first demonstrated in a photonic trimer system with nearly equal pumping for the two extreme cavities. Nonetheless, the conventional photonic zero modes, distinguished by their out-of-phase emission and the boundary-confined intensity distribution, significantly restrict their applications. We tackle the two aforementioned limitations by the barrier-image engineering technique and the non-Hermiticity. The former can flip the sign of the inter-cavity coupling and generate an in-phase zero mode; the latter can leverage a bulk zero mode through the spontaneous restoration of non-Hermitian particle-hole symmetry. In order to address zero modes in larger coupled-cavity arrays, we investigate the emergence of both EP and zero modes in a two-dimensional structure including four coupled nanolasers arranged in a ring. The non-Hermitian chiral symmetry generates a zero mode through a collision of modes at the EP, which is further stabilized by nonlinear saturation. Interestingly, the modes at EP exhibit a phase singularity, resulting in an optical vortex, which is experimentally observed using near-field interference. This thesis concludes with the presentation of an intriguing application of the zero mode: optical computing capabilities. We demonstrate both theoretically and experimentally that our nanolasers can address non-trivial classification tasks, which prove to be challenging for a single-layer neural network architecture. The complex nanolaser layer markedly enhances computing accuracy, particularly for low dimensional input datasets
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Gleeson, Liam M. "Polarisation mode dispersion in non-return-to-zero systems : assessment and impact." Thesis, University of Essex, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.343569.
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Walters, David Nathan. "The 3+1 dimensional lattice NJL model at non-zero baryon density." Thesis, Swansea University, 2003. https://cronfa.swan.ac.uk/Record/cronfa42346.
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Lattice simulations of the 3+1 dimensional Nambu-Jona-Lasinio model are undertaken that provide non-perturbative evidence for the existence of a BCS superfluid phase in the low temperature, high density regime. Standard analytic methods are used to fit the model's free parameters to low energy vacuum phenomenology. The model is simulated numerically for a range of baryon chemical potential mu, with the introduction of a diquark source j to allow for the observation of spontaneous U(1) global symmetry breaking in a finite volume system. For mu ≥ 0.6 inverse lattice spacings and in the limit that j → 0, a non-zero diquark condensate, a vanishing diquark susceptibility ratio and an energy gap Delta ≠ 0 about the Fermi surface in the fermion dispersion relation are all consistent with the ground-state being that of a U(l)-broken BCS superfluid. The ratio between the gap at mu = 0.8 and the vacuum fermion mass is found to be 0.15(2). This is interpreted as tentative non-perturbative evidence for the existence of a colour superconducting phase in cold, dense QCD. The effects of simulating on a finite volume, and any conditions this places on the above conclusions, are investigated. Finally, the results of some initial studies at non-zero isospin chemical potential and the prospect of simulations at non-zero temperature are discussed.
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Tiwari, Railesha. "A Decision-Support Framework for Design of Non-Residential Net-Zero Energy Buildings." Diss., Virginia Tech, 2015. http://hdl.handle.net/10919/73301.
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Designing Net-Zero Energy Buildings (NZEB) is a complex and collaborative team process involving knowledge sharing of experts leading to the common goal of meeting the Net-Zero Energy (NZE) project objectives. The decisions made in the early stages of design drastically affect the final outcome of design and energy goals. The Architecture, Engineering and Construction (AEC) industry is pursuing ways to improve the current building design process and project delivery methods for NZEBs. To enable the building industry to improve the building design process, it is important to identify the gaps, ways of improvement and potential opportunities to structure the decision-making process for the purpose of NZE performance outcome. It is essential to identify the iterative phases of design decisions between the integrated team of experts for the design processes conducted in these early stages to facilitate the decision-making of NZEB design. The lack of a structured approach to help the AEC industry in making informed decisions for the NZEB context establishes the need to evaluate the argumentation of the NZEB design decision process. The first step in understanding the NZEB design decision process is to map the current processes in practice that have been successful in achieving the NZE goal. Since the energy use performance goal drives the design process, this research emphasizes first the need to document, in detail, and investigate the current NZEB design process with knowledge mapping techniques to develop an improved process specific to NZEB context.
In order to meet this first objective, this research qualitatively analyzed four NZEB case studies that informed decision-making in the early design phases. The four components that were studied in the early design phases included (1) key stakeholders involved (roles played), (2) phases of assessments (design approach, (3) processes (key processes, sub-processes and design activities affecting performance) and (4) technology (knowledge type and flow). A series of semi-structured, open-ended interviews were conducted with the key decision-makers and decision facilitators to identify their roles in the early design processes, the design approach adopted, rationale for decision-making, types of evaluations performed, and tools used for analysis. The qualitative data analysis was performed through content analysis and cognitive mapping techniques. Through this process, the key phases of decision-making were identified that resulted in understanding of the path to achieving NZE design goal and performance outcome.
The second objective of this research was to identify the NZE decision nodes through a comparative investigation of the case studies. This research also explored the key issues specific to each stakeholder group. The inter-relationships between the project objectives, decision context, occupants usage patterns, strategies and integrated systems, building operation and renewable energy production was identified through a series of knowledge maps and visual process models leading to the identification of the key performance indicators. This research reviewed the similarities and differences in the processes to identify significant opportunities that can improve the early building design process for NZEBs. This research identifies the key decision phases used by the integrated teams and describes the underlying structure that can change the order of key phases.
A process mapping technique was adapted to capture the practice-based complex NZEB design approach and draw insights of the teamwork and interdisciplinary communication to enable more comprehensive understanding of linkages between processes, sub-processes and design activities, knowledge exchange, and decision rationale. Ket performance indicators identified for early design of NZEBs resulted in developing a decision-support process model that can help the AEC industry in making informed decisions. This dissertation helps improve understanding of linkages between processes, decision nodes and decision rationale to enable industry-wide NZEB design process assessment and improvement. This dissertation discusses the benefits the proposed NZEB design process model brings to the AEC industry and explores future development efforts.<br>Ph. D.
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Antolin, Nikolas. "Density-Functional Theory Study of Materials and Their Properties at Non-Zero Temperature." The Ohio State University, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=osu1452253704.
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Phillips, Michael James. "A random matrix model for two-colour QCD at non-zero quark density." Thesis, Brunel University, 2011. http://bura.brunel.ac.uk/handle/2438/5084.
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We solve a random matrix ensemble called the chiral Ginibre orthogonal ensemble, or chGinOE. This non-Hermitian ensemble has applications to modelling particular low-energy limits of two-colour quantum chromo-dynamics (QCD). In particular, the matrices model the Dirac operator for quarks in the presence of a gluon gauge field of fixed topology, with an arbitrary number of flavours of virtual quarks and a non-zero quark chemical potential. We derive the joint probability density function (JPDF) of eigenvalues for this ensemble for finite matrix size N, which we then write in a factorised form. We then present two different methods for determining the correlation functions, resulting in compact expressions involving Pfaffians containing the associated kernel. We determine the microscopic large-N limits at strong and weak non-Hermiticity (required for physical applications) for both the real and complex eigenvalue densities. Various other properties of the ensemble are also investigated, including the skew-orthogonal polynomials and the fraction of eigenvalues that are real. A number of the techniques that we develop have more general applicability within random matrix theory, some of which we also explore in this thesis.
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Abel, Guy. "Non-zero trajectories for long-run net migration assumptions in global population projection models." Max Planck Institute for Demographic Research, 2018. http://epub.wu.ac.at/6387/1/38%2D54.pdf.
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BACKGROUND
Little attention is given to the role of migration in global population projection models.
Most demographers set future levels of net migration on trajectories towards zero in all
countries, nullifying the impact of migration on long-run projected populations. Yet as
fertility and mortality rates fall, the role of migration on future population change is
becoming more pronounced.
OBJECTIVES
In this paper we develop future long-run migration scenarios to provide a range of
possible outcomes.
METHODS
Our alternative migration scenarios are linked to the Shared Socioeconomic Pathways
(SSP), widely used in research on global environmental change. These are utilized as
inputs for a global cohort component projection model to obtain population totals up
until 2100 for all countries.
CONTRIBUTION
The results illustrate the important role of migration assumptions in long-run
projections, especially in post-demographic-transition countries. Further, they provide
plausible alternatives to projections based on the commonly used, but poorly justified,
convergence towards a zero net migration assumption.
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Yamashita, Kyousuke. "A Study of Non-Interactive Zero-Knowledge Proof Systems in a Black-Box Framework." Doctoral thesis, Kyoto University, 2021. http://hdl.handle.net/2433/263778.
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Galassi, De Orchi Tommaso. "A Security Study for Non-Internet Connected Managed Software." Thesis, KTH, Kommunikationssystem, CoS, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-99047.
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This master thesis project aims to improve the security of managed software developed at SCANIA's research and development group NEVE. The thesis will present several security schemes that can be effective against tampering, theft, and reverse engineering of application. The schemes presented were selected to ensure confidentiality, integrity, authenticity, and authentication of applications. NEVE’s software will be analyzed and compared against state of the art solutions. A theoretical threat analysis will be presented, corroborated by empirical reverse engineering attacks. The final part of this thesis introduces a new security scheme for C# .NET programs operating without requiring an internet connection.<br>Denna uppsats försöker förbättra säkerheten av [managed software] utvecklad hos SCANIAS forsknings- och utvecklingsgrupp NEVE. Den visar på flera säkerhetslösningar som kan vara effektiva mot manipulation, stöld och omvänd ingenjörskonst av applikationer. De säkerhetslösningar som presenteras valdes för att säkerställa sekretess, integritet, äkthet och autentisering hos applikationer. NEVEs mjukvara kommer att analyseras och ställs mot de allra senaste lösningarna. En teoretisk hotanalys kommer att presenteras, förstärkt med attacker baserat empiriskt omvänd ingenjörskonst. Den sista delen av denna uppsats introducerar en ny säkerhetslösning. Den riktar sig mot program skrivna i C# .NET som inte kräver en uppkoppling mot internet.
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Hedir, Melissa. "Design, study, and fabrication of photonic crystal coupled-cavity arrays for investigating non-Hermitian zero-modes." Electronic Thesis or Diss., université Paris-Saclay, 2024. http://www.theses.fr/2024UPASP056.
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Les cavités couplées à base de cristal photonique (PhC) représentent des plates-formes intéressantes pour de nombreux protocoles d'information ou de calcul, tant classiques que quantiques. Elles servent également de bancs d'essai très polyvalents pour étudier des phénomènes optiques avancés, tels que les zero-modes photoniques non Hermitiens. Ces zero-modes, des états liés intrigants ayant suscité l'intérêt à travers le cas des zero-modes de Majorana, présentent des valeurs propres d'énergie nulle dans un réseau de cavités ou de guides d'ondes. En tant que modes protégés topologiquement ou symétriquement, on s'attend à ce qu'ils soient robustes face aux désordres de couplage, ouvrant ainsi un large éventail d'applications, de l'ingénierie des modes laser au calcul optique. Ce travail de thèse présentel'observation expérimentale des zer-modes photoniques dans des réseaux unidimensionnels de cavités couplées présentant une distribution de gain/perte, également appelés réseaux non Hermitiens. Notre étude s'est focalisée sur des réseaux composés d'un nombre impair de cavités (trois et cinq). Nous avons notamment constaté que le contrôle du couplage évanescent entre les cavités modifie considérablement le désaccord en fréquence, ce qui entrave la réalisation des zero-modes. Pour contourner ce problème, nous avons développé un nouveau design que nous avons appelée "technique d'ingénierie des barrières images", permettant un contrôle précis de la force de couplage au sein de réseaux unidimensionnels de cavités couplées sans le désaccord en fréquence concomitant causé par les terminaisons dans la chaîne, élargissant ainsiconsidérablement la plage d'observabilité des modes zéro. Cette méthode facilite également la construction de chaînes de cavités avec un couplage non uniforme, ce qui nous permet d'évaluer l'immunité inhérente des zero-modes face aux perturbations de couplage. Remarquablement, la capacité à inverser les signes de couplage permise par notre méthode de contrôle du couplage conduit à une inversion de la symétrie du zero-mode, permettant donc d'élargir le potentiel pour des investigations expérimentales et théoriques de ces modes. Cela offre une possibilité de réaliser une oscillation de zero-mode en phase, une caractéristique intéressante pour exalter le champ lointain des lasers topologiques<br>Coupled photonic crystal (PhC) cavities are outstanding platforms for many classical and quantum information or computing protocols. They are also highly versatile testbeds for exploring advanced collective optical phenomena, such as the so-called non-Hermitian photonic zero modes. Zero modes are intriguing bound states that have captured attention through the elusive case of Majorana zero modes. In optics, “photonic zero-modes” exhibit zero-energy eigenvalues in a cavity or waveguide array. Being topologically or symmetry-protected modes, they are expected to be robust against coupling disorder, opening up a wide range of applications, from laser mode engineering to optical computing. This thesis work presents the experimental observation of photonic zero modes in small coupled cavity arrays featuring a gain/loss distribution -also called non-Hermitian arrays composed of an odd number of photonic crystal (PhC) cavities, from three to five. Importantly,we have found that controlling the evanescent coupling between the cavities significantly alters the frequency detuning which hampers the realization of zero modes.To address this issue, we developed a new design that we called “image barrier ” engineering technique, which enables precise control of coupling strength within 1D arrays of coupled cavities without the concomitant frequency detuning caused byterminations in the chain, thus, significantly expanding the observability range of zero modes. This method also facilitates the construction of cavity chains with nonuniform coupling, thus allowing us to assess the inherent immunity of zero modesto coupling perturbations. Remarkably, the ability to invert coupling signs enabled by our coupling control method leads to achieving an inversion of the zero mode's symmetry, broadening the potential for experimental and theoretical investigationsof these modes, either symmetry or topologically protected. This gives a handle to realize in-phase zero-mode oscillation, a crucial requirement to improve the far-field of topological lasers
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Han, Chang Woon. "Shadow moiré using non-zero talbot distance and application of diffraction theory to moiré interferometry." College Park, Md. : University of Maryland, 2005. http://hdl.handle.net/1903/2352.
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Thesis (Ph. D.) -- University of Maryland, College Park, 2005.<br>Thesis research directed by: Mechanical Engineering. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
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Kaczmarek, Olaf [Verfasser]. "The heavy quark mass limit of QCD at non-zero baryon number density / Olaf Kaczmarek." Bielefeld : Universitätsbibliothek Bielefeld, 2000. http://d-nb.info/1034401211/34.
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Scarlet, Benjamin S. 1974. "Solving sign problems with meron cluster algorithms : simulating field theories at non-zero chemical potential." Thesis, Massachusetts Institute of Technology, 2000. http://hdl.handle.net/1721.1/8280.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Physics, February 2001.<br>Includes bibliographical references (p. 97-102) and index.<br>Numerical simulation of quantum systems develop sign problems upon the introduction of a chemical potential. The sign problem thus makes many interesting physical systems very difficult to study numerically. In this thesis, two related systems which develop sign problems in this way are considered: a D-Theory representation of a 1+1 dimensional 0(3) quantum field theory with a chemical potential, and antiferromagnetic Heisenberg quantum spin ladders in a magnetic field. In both cases, meron cluster algorithms are used to completely solve the sign problem. Using these algorithms, numerical results were generated in the two models for, respectively, the particle number as a function of the chemical potential and magnetization as a function of the external field. These results are in agreement with corresponding analytic predictions.<br>by Benjamin S. Scarlet.<br>Ph.D.
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Obranovich, Michael A. "The effects of non-zero neutrino masses on the CMB determination of the cosmological parameters." The Ohio State University, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=osu1337799009.
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Yan, Guqi. "Zero-group-velocity Lamb modes in laser ultrasonics : fatigue monitoring and material characterization." Thesis, Le Mans, 2018. http://www.theses.fr/2018LEMA1026/document.
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Ces dernières années, les modes de Lamb à vitesse de groupe nulle (ZGV) se sont révélés être un outil efficace pour sonder localement et précisément l'épaisseur d'un échantillon ou les propriétés mécaniques de matériaux isotropes ou anisotropes. Ce type particulier d'ondes guidées, telles de fortes résonances locales de la structure, résulte de l'interférence de deux ondes de Lamb ayant une vitesse de phase opposée et coexistant pour un couple fréquence-nombre d'ondes particulier. Les ultrasons laser ont démontré leur capacité à générer et détecter efficacement de telles résonances locales dans la gamme des MHz. En effet, la configuration tout optique, constituée d'une source laser pulsée pour générer les ondes élastiques et d'un interféromètre pour sonder le déplacement normal associé, évite tout contact avec l'échantillon, limitant ainsi l'élargissement ou la suppression de résonances. L'utilisation de modes ZGV pour suivre la fatigue des matériaux et sonder des phénomènes non linéaires reste cependant un défi et constitue le cœur des travaux de recherche présentés ici. La partie théorique porte sur la compréhension de l’effet de la fatigue mécanique sur les modes ZGV à travers l’analyse fréquence-nombre d’ondes des modes de Lamb. La partie expérimentale est consacrée à l’application de cette technique pour l'ECND et le suivi de la fatigue de plaques métalliques minces. Les modes ZGV en ultrasons laser montrent un grand potentiel pour localiser les dommages dus à la fatigue, prédire la vie en fatigue et évaluer qualitativement, voire quantitativement, les différents stades de dommages causés par la fatigue<br>In recent years, zero-group-velocity (ZGV) Lamb modes have proven to be an efficient tool to probe locally and very accurately the thickness of a sample or the mechanical properties of either isotropic or anisotropic materials. This particular type of guided waves, corresponding to sharp local resonances of the structure, results of the interference of two Lamb waves having opposite phase velocity and coexisting at a couple given frequency-wavenumber. The laser ultrasonic technique has demonstrated its ability to efficiently generate and detect such local resonances within the MHz frequency range. Indeed, the all-optical setup, consisting of a pulsed laser source to generate elastic waves and of an interferometer to probe the associated normal displacement, avoids any contact with the sample, hence limiting the broadening or suppression of the resonances. Yet, the use of ZGV Lamb modes to monitor material fatigue and to probe nonlinear phenomena remains challenging and is the core of the here-reported research. The theoretical part of this PhD research deals with the understanding of the effect of mechanical fatigue on ZGV Lamb modes through the frequency-wavenumber analyzes of the Lamb waves. The experimental part of the PhD research is dedicated to the application of this technique for the nondestructive characterization and for the monitoring of mechanical and thermal fatigue of thin metal plates. Zero-group-velocity Lamb modes in laser ultrasonics shows great promises to locate fatigue damage, to predict the fatigue lifetime, and to qualitatively, and even quantitatively, assess the different stages of fatigue damage in m- to potentially cm-thick solid plates
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Kwan, Man Ho. "Electroabsorption-modulator based clock recovery circuit for high-speed optical non-return-to-zero (NRZ) signals /." View abstract or full-text, 2005. http://library.ust.hk/cgi/db/thesis.pl?ELEC%202005%20KWAN.
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Neofytidis, Christoforos [Verfasser], and Dieter [Akademischer Betreuer] Kotschick. "Non-zero degree maps between manifolds and groups presentable by products / Christoforos Neofytidis. Betreuer: Dieter Kotschick." München : Universitätsbibliothek der Ludwig-Maximilians-Universität, 2014. http://d-nb.info/1054599114/34.
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Ellingsen, Simen Andreas Ådnøy. "Dispersion forces in Micromechanics : Casimir and Casimir-Polder forces affected by geometry and non-zero temperature." Doctoral thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for energi- og prosessteknikk, 2011. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-12365.
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The present thesis focuses on several topics within three separate but related branches of the overall field of dispersion forces. The three branches are: temperature corrections to the Casimir force between real materials (Part 1), explicit calculation of Casimir energy in wedge geometries (Part 2), and Casimir-Polder forces on particles out of thermal equilibrium (Part 3). Part 1 deals primarily with analysis of a previously purported thermodynamic inconsistency in the Casimir-Lifshitz free energy of the interaction of two plane mirrors – violation of the third law of thermodynamics – when the latter’s dielectric response is described with dissipative models. It is shown analytically and numerically that the Casimir entropy of the interaction between two metallic mirrors described by the Drude model does tend to zero at zero temperature, provided electronic relaxation does not vanish. The leading order terms at low temperature are found. A similar calculation is carried out for the interaction of semiconductors with small but non-zero DC conductivity. In a generalisation, it is shown that a violation of the third law can only occur for permittivities whose low-frequency behaviour is temperature dependent near zero temperature. A calculation using path integral methods shows that the low temperature behaviour of the interaction of fluctuating Foucault currents in two mirrors of Drude metal is identical to that of the full Casimir-Lifshitz free energy, reasserting a previous finding by Intravaia and Henkel that such fluctuating bulk currents are the physical reason for the anomalous entropy behaviour. In a related effort, an analysis of the frequency dependence of the Casimir force by Ford is generalised to imperfectly reflecting mirrors. A paradox is pointed out, in that the effects of a perturbation of the reflecting properties of the mirrors in a finite frequency window can be calculated in two ways giving different results. It is concluded that optimistic conclusions reached by Ford based on one of these methods, which seems to allow radically changing and tailoring the Casimir force with engineered materials, can not be realised. Part 2 presents several explicit calculations of the Casimir energy of different wedge and cylinder geometries. The Casimir energy of a perfectly conducting wedge intercut by a circularly cylindrical arc, either perfectly conducting or (magneto)dielectric, is calculated. The energy is found to include a singular and non-regularisable term due to the corners where the arc meets the wedge, whereas the finite part is an immediate generalisation of the previously known results for a circular cylinder. The energy of a magnetodielectric wedge obeying a criterion of isorefractivity (spatially uniform speed of light) superimposed coaxially on a perfectly conducting cylindrical shell is calculated. This is the first expression for the energy of a wedge which is not perfectly reflecting. Finally, the energy of the perfectly conducting wedge and arc (and, as a special case, cylinder) is extended to the case of non-zero temperatures. After a regularisation procedure making use of the Chowla-Selberg formula an analytical expression for the temperature-dependent energy at all temperatures is derived, and showed to coincide with previously calculated high-temperature asymptotics by Bordag, Nesterenko and Pirozhenko. Part 3 considers numerical and analytical studies of the Casimir-Polder forces acting on particles prepared in a given eigenstate (or superposition of such) in an environment which is otherwise at thermal equilibrium. We first consider cold polar molecules outside a metallic halfspace. It is found that the force in the near-zone (non-retarded regime) is much weaker than what would result from a naïve perturbative calculation, and that in the far-zone (retarded regime) the force becomes spatially oscillatory. It is demonstrated how these spatial oscillations may be enhanced in a resonating planar cavity, although for polar molecules the resulting amplitude is still insufficient for observation. A cylindrical cavity, however, can achieve a better enhancement factor. The Casimir-Polder forces on Rydberg atoms near a surface are calculated; because of the very large transition dipole moments of Rydberg transitions, the force is enormous on an atomic scale. We show that the oscillating force on Rydberg atoms can be enhanced into the observable regime by use of a fine-tuned cylindrical cavity. A particle in an eigenstate which is in the non-retarded regime with respect to all its dominant transitions is shown to feel a Casimir-Polder force which is virtually independent of temperature from zero to room temperature and beyond. Both for cold polar molecules and Rydberg atoms, the temperature-independent regime extends to a few and hundreds of micrometers, respectively, and includes the separations generally accessed in experiments
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Swallow, Ben. "Bayesian multi-species modelling of non-negative continuous ecological data with a discrete mass at zero." Thesis, University of St Andrews, 2015. http://hdl.handle.net/10023/9626.
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Severe declines in the number of some songbirds over the last 40 years have caused heated debate amongst interested parties. Many factors have been suggested as possible causes for these declines, including an increase in the abundance and distribution of an avian predator, the Eurasian sparrowhawk Accipiter nisus. To test for evidence for a predator effect on the abundance of its prey, we analyse data on 10 species visiting garden bird feeding stations monitored by the British Trust for Ornithology in relation to the abundance of sparrowhawks. We apply Bayesian hierarchical models to data relating to averaged maximum weekly counts from a garden bird monitoring survey. These data are essentially continuous, bounded below by zero, but for many species show a marked spike at zero that many standard distributions would not be able to account for. We use the Tweedie distributions, which for certain areas of parameter space relate to continuous nonnegative distributions with a discrete probability mass at zero, and are hence able to deal with the shape of the empirical distributions of the data. The methods developed in this thesis begin by modelling single prey species independently with an avian predator as a covariate, using MCMC methods to explore parameter and model spaces. This model is then extended to a multiple-prey species model, testing for interactions between species as well as synchrony in their response to environmental factors and unobserved variation. Finally we use a relatively new methodological framework, namely the SPDE approach in the INLA framework, to fit a multi-species spatio-temporal model to the ecological data. The results from the analyses are consistent with the hypothesis that sparrowhawks are suppressing the numbers of some species of birds visiting garden feeding stations. Only the species most susceptible to sparrowhawk predation seem to be affected.
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Heide, Johannes van der. "The pion form factor from lattice QCD a non-perturbative study at zero and finite temperature /." [S.l. : Amsterdam : s.n.] ; Universiteit van Amsterdam [Host], 2004. http://dare.uva.nl/document/76697.
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Okamoto, Toshihiro. "Successful Sub-zero Non-freezing Preservation of Rat Lungs at -2℃ Utilizing a New Supercooling Technology." Kyoto University, 2010. http://hdl.handle.net/2433/120596.
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Buso, Tiziana. "Nearly Zero Energy multi-functional Buildings - Energy and Economic evaluations." Doctoral thesis, Politecnico di Torino, 2017. http://hdl.handle.net/11583/2690913.
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Building energy renovation is one of the pillars upon which the 2050 European low-carbon goals are based. Simultaneously, building energy renovation is widely recognized as the trump card for the new start of European economy. However, at present the renovation rate of the existing building is very low throughout Europe (approximately 1%) and investments in high performing buildings are generally mistrusted by stakeholders, due to their high capital costs.
In this context, this PhD thesis dedicated its efforts to investigate from the energy and financial perspective the consequences of buildings renovation in the European scene. Particularly, the research boundaries were delineated by focusing on non-residential, multi-functional buildings, that are nowadays poorly studied due to their heterogeneous nature.
In this view, the thesis’ contributions were addressed at three levels:
a) multi-functional buildings as archetypes to input in energy models for long-term energy analysis;
b) multi-functional buildings used to test the financial viability of energy efficiency projects, in view of reaching the nearly Zero Energy performance level. As these analyses necessarily require case studies, the attention was directed towards a specific type of multi-functional buildings, hotels;
c) multi-functional buildings as test-bed to assess the impact of co-benefits on the financial performances of energy efficiency projects. Once again, hotel buildings were selected for the development of the detailed analyses.
To include archetypes of multi-functional buildings in bottom-up building energy models, a new modelling method was proposed. The method provides a rationale for the classification of energy end-uses into typical and extra, so that the modeling problem is simplified and a coherent use of well-established Reference Buildings modelling methods is allowed.
Then, the focus of the research was narrowed to the hotel sector, which was found to lack of reliable energy performance benchmarks and effective performance-based greens labels. Case study buildings were object of energy and financial evaluations. On one side, real hotels were analyzed to test the application of the EU imposed cost-optimal methodology as a support tool to guide private investors’ investment decisions. On the other side, an Italian Reference Hotel was modelled and the cost-optimal methodology was applied to investigate the existing energy and financial gaps between cost-optimal and Nearly Zero Energy performance level in Italy. From both perspectives, findings converged to similar conclusions: high performing retrofit are not financially viable, if avoided energy costs are the only operational benefits accounted for.
Starting from these outcomes, the thesis investigated how valuation procedures could be exploited to make NZEB retrofit solutions appealing for private investors. Based on a literature review of the co-benefits of energy efficiency projects, 2 different strategies were pursued and tested on the Italian Reference Hotel. The first approach proposed to monetize co-benefits of energy efficiency interventions based on literature and to include them in the well-established cost-optimal methodology. Results highlighted that co-benefits related to the market appreciation of a retrofitted hotel can drastically change the perception of the financial convenience of an ambitious retrofit project. In the latter strategy, the issue of monetizing non-energy benefits was faced directly: a technique to value non-market goods was applied to monetize comfort. Findings proved that hotels guests’ willingness to pay for comfortable indoor conditions is higher than the hoteliers’ extra costs for providing them. Due to the context-dependent nature of co-benefits, the findings of the 2 applications do not represent generally applicable quantitative benchmarks. Nonetheless, they confirm the leading role that literature attribute to co-benefits in the success of energy efficiency projects.
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Harvie, Dawn Marie. "Tracking down old relatives, zero relatives in subject and non-subject function in early African American english." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp03/MQ38754.pdf.
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Wang, Wei. "CAUSAL MEDIATION ANALYSIS FOR NON-LINEAR MODELS." Case Western Reserve University School of Graduate Studies / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=case1332961697.
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MEDEIROS, Rex Antonio da Costa. "Zero-Error capacity of quantum channels." Universidade Federal de Campina Grande, 2008. http://dspace.sti.ufcg.edu.br:8080/jspui/handle/riufcg/1320.
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Previous issue date: 2008-05-09<br>Nesta tese, a capacidade erro-zero de canais discretos sem memória é generalizada para
canais quânticos. Uma nova capacidade para a transmissão de informação clássica através de canais quânticos é proposta. A capacidade erro-zero de canais quânticos (CEZQ) é definida como sendo a máxima quantidade de informação por uso do canal que pode ser enviada através de um canal quântico ruidoso, considerando uma probabilidade de erro igual a zero. O protocolo de comunicação restringe palavras-código a produtos tensoriais de estados quânticos de entrada, enquanto que medições coletivas entre várias saídas do canal são permitidas. Portanto, o protocolo empregado é similar ao protocolo de Holevo-Schumacher-Westmoreland. O problema de encontrar a CEZQ é reformulado usando elementos da teoria de grafos. Esta definição equivalente é usada para demonstrar propriedades de famílias de estados quânticos e medições que atingem a CEZQ. É mostrado
que a capacidade de um canal quântico num espaço de Hilbert de dimensão d pode sempre ser alcançada usando famílias compostas de, no máximo,d estados puros. Com relação às medições, demonstra-se que medições coletivas de von Neumann são necessárias e suficientes para alcançar a capacidade. É discutido se a CEZQ é uma generalização não trivial da capacidade erro-zero clássica. O termo não trivial refere-se a existência de canais quânticos para os quais a CEZQ só pode ser alcançada através de famílias de estados quânticos não-ortogonais e usando códigos de comprimento maior ou igual a dois. É investigada a CEZQ de alguns canais quânticos. É mostrado que o problema de calcular a CEZQ de canais clássicos-quânticos é puramente clássico. Em particular, é exibido um canal quântico para o qual conjectura-se que a CEZQ só pode ser alcançada usando uma família de estados quânticos não-ortogonais. Se a conjectura é verdadeira, é possível calcular o valor exato da capacidade e construir um código de bloco quântico que alcança a capacidade. Finalmente, é demonstrado que a CEZQ é limitada superiormente pela capacidade de Holevo-Schumacher-Westmoreland.
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Thompson, Alasdair Graham. "Lattice models of pattern formation in bacterial dynamics." Thesis, University of Edinburgh, 2012. http://hdl.handle.net/1842/6248.
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In this thesis I study a model of self propelled particles exhibiting run-and tumble dynamics on lattice. This non-Brownian diffusion is characterised by a random walk with a finite persistence length between changes of direction, and is inspired by the motion of bacteria such as Escherichia coli. By defining a class of models with multiple species of particle and transmutation between species we can recreate such dynamics. These models admit exact analytical results whilst also forming a counterpart to previous continuum models of run-and- tumble dynamics. I solve the externally driven non-interacting and zero-range versions of the model exactly and utilise a field theoretic approach to derive the continuum fluctuating hydrodynamics for more general interactions. I make contact with prior approaches to run-and-tumble dynamics of lattice and determine the steady state and linear stability for a class of crowding interactions, where the jump rate decreases as density increases. In addition to its interest from the perspective of nonequilibrium statistical mechanics, this lattice model constitutes an efficient tool to simulate a class of interacting run-and-tumble models relevant to bacterial motion. Pattern formation in bacterial colonies is confirmed to be able to stem solely from the interplay between a diffusivity that depends on the local bacterial density and regulated division of the cells, in particular without the need for any explicit chemotaxis. This simple and generic mechanism thus provides a null hypothesis for pattern formation in bacterial colonies which has to be falsified before appealing to more elaborate alternatives. Most of the literature on bacterial motility relies on models with instantaneous tumbles. As I show, however, the finite tumble duration can play a major role in the patterning process. Finally a connection is made to some real experimental results and the population ecology of multiple species of bacteria competing for the same resources is considered.
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Davis, Simon. "On the existence of a non-zero lower bound for the number of Goldbach partitions of an even integer." Universität Potsdam, 2002. http://opus.kobv.de/ubp/volltexte/2008/2647/.
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The Goldbach partitions of an even number greater than 2, given by the sums of two prime addends, form the non-empty set for all integers 2n with 2 ≤ n ≤ 2 × 1014. It will be shown how to determine by the method of induction the existence of a non-zero lower bound for the number of Goldbach partitions of all even integers greater than or equal to 4. The proof depends on contour arguments for complex functions in the unit disk.
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Ljung, Carolina, and Maria Svedberg. "Estimation of Loss Given Default Distributions for Non-Performing Loans Using Zero-and-One Inflated Beta Regression Type Models." Thesis, KTH, Matematisk statistik, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-273593.
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This thesis investigates three different techniques for estimating loss given default of non-performing consumer loans. This is a contribution to a credit risk evaluation model compliant with the regulations stipulated by the Basel Accords, regulating the capital requirements of European financial institutions. First, multiple linear regression is applied, and thereafter, zero-and-one inflated beta regression is implemented in two versions, with and without Bayesian inference. The model performances confirm that modeling loss given default data is challenging, however, the result shows that the zero-and-one inflated beta regression is superior to the other models in predicting LGD. Although, it shall be recognized that all models had difficulties in distinguishing low-risk loans, while the prediction accuracy of riskier loans, resulting in larger losses, were higher. It is further recommended, in future research, to include macroeconomic variables in the models to capture economic downturn conditions as well as adopting decision trees, for example by applying machine learning.<br>Detta examensarbete undersöker tre olika metoder för att estimera förlusten vid fallissemang för icke-presterande konsumentlån. Detta som ett bidrag till en kreditrisksmodell i enlighet med bestämmelserna i Baselregelverken, som bland annat reglerar kapitalkraven för europeiska finansiella institut. Inledningsvis tillämpas multipel linjär regression, därefter implementeras två versioner av utvidgad betaregression, med och utan bayesiansk inferens. Resultatet bekräftar att modellering data för förlust givet fallissemang är utmanande, men visar även att den utvidgade betaregressionen utan bayesiansk inferens är bättre de andra modellerna. Det ska dock tilläggas att alla modeller visade svårigheter att estimera lån med låg risk, medan tillförlitligheten hos lån med hög risk, vilka generellt sett medför större förluster, var högre. Vidare rekommenderas det för framtida forskning att inkludera makroekonomiska variabler i modellerna för att fånga ekonomiska nedgångar samt att implementera beslutsträd, exempelvis genom applicering av maskininlärning.
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Sinha, Piyush M. "Nanoengineered implantable devices for controlled drug delivery." The Ohio State University, 2005. http://rave.ohiolink.edu/etdc/view?acc_num=osu1115138930.
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Cain, Tyler Joshua. "Central Asian energy policy : cooperative non-zero sum policy on legal status and pipeline issues benefit local and global actors." Honors in the Major Thesis, University of Central Florida, 2008. http://digital.library.ucf.edu/cdm/ref/collection/ETH/id/1068.
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This item is only available in print in the UCF Libraries. If this is your Honors Thesis, you can help us make it available online for use by researchers around the world by following the instructions on the distribution consent form at http://library.ucf.edu/Systems/DigitalInitiatives/DigitalCollections/InternetDistributionConsentAgreementForm.pdf You may also contact the project coordinator, Kerri Bottorff, at kerri.bottorff@ucf.edu for more information.<br>Bachelors<br>Sciences<br>Political Science
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Rosales, Núñez José. "Machine Translation of User-Generated Contents : an Evaluation of Neural Translation Systems under Zero-shot Conditions." Electronic Thesis or Diss., université Paris-Saclay, 2023. http://www.theses.fr/2023UPASG058.
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Les avancées rapides des télécommunications au cours des dernières décennies ont révolutionné la manière dont les gens échangent des informations. Grâce à ces progrès, l'utilisateur moyen peut désormais communiquer avec d'autres personnes à travers le monde en temps réel et avec un délai minimal. Avec environ 60 % de la population mondiale ayant accès à Internet, des milliards d'individus interagissent en partageant du contenu généré par les utilisateurs (UGC) sous diverses formes. Ce contenu généré par les utilisateurs, qui comprend souvent des critiques et des opinions, constitue une source précieuse d'informations, offrant une vue d'ensemble des tendances mondiales. La traduction automatique joue un rôle vital en permettant une communication fluide et en facilitant le traitement automatique de l'UGC à des fins d'exploration de données.Cependant, la traduction des UGC présente des défis uniques par rapport à la traduction d'un texte traditionnel. L'UGC est très productif et présente divers phénomènes tels que des caractères répétés, des erreurs typographiques, des contractions, du jargon et des structures de phrases non conventionnelles. Ces spécificités entraînent un nombre important de mots hors vocabulaire (OOV) et de séquences rares, qui posent des problèmes car ils ne sont pas représentés de manière adéquate dans les corpus parallèles standard utilisés pour entraîner les modèles de traduction automatique. En outre, les techniques conventionnelles d'adaptation au domaine, telles que le “fine-tuning”, n'ont qu'un succès limité dans la résolution de ces problèmes. Elles souffrent d'une dégradation des performances lorsqu'elles sont appliquées aux données du domaine et ne sont pas en mesure de suivre l'évolution constante de la nature de l'UGC.Dans cette étude, nous nous concentrons sur la tâche de traduction automatique des UGC dans le scénario "zero-shot", où nous nous abstenons d'utiliser des données d'apprentissage spécifiques aux UGC. Notre objectif est de développer des architectures de traduction automatique plus généralisées, capables de gérer le “distributional shift”, inhérente à l'évaluation de la traduction des UGC. Dans la phase initiale de notre recherche, nous avons consacré nos efforts à l'identification et à la quantification des spécificités de l'UGC qui entravent la performance de la traduction. Nous avons également créé des cadres d'évaluation et des collections de données pour nous aider dans cette tâche. À l'aide de modèles “off-the-shelf”, nous étudions les difficultés rencontrées par les systèmes de traduction automatique lorsqu'ils traduisent des UGC et nous établissons un lien entre les erreurs et les mécanismes sous-jacents.Ensuite, nous nous penchons sur l'étude et la proposition de différentes méthodes pour relever les défis posés par l'UGC. Ces méthodes comprennent l'exploration des pipelines de normalisation, l'emploi de techniques de tokenisation plus granulaires et l'utilisation de modèles de variables latentes pour améliorer la robustesse des systèmes de traduction automatique. Pour chacune de ces approches, nous évaluons systématiquement les performances et la robustesse des systèmes, nous effectuons une analyse détaillée des erreurs et nous proposons des pistes prometteuses pour aborder la traduction automatique des UGC dans une évaluation “zéro-shot”<br>The rapid advancements in telecommunications over the past few decades have revolutionized the way people exchange information. Thanks to these advancements, the average user can now communicate with others across the globe in real-time and with minimal delay. With approximately 60% of the global population having Internet access, billions of individuals interact by sharing user-generated content (UGC) in various forms. This UGC, which often includes reviews and opinions, provides a valuable source of information, offering a comprehensive view of global trends. Machine Translation (MT) plays a vital role in enabling smooth communication and facilitating the automatic processing of UGC for data mining purposes.However, translating UGC presents unique challenges compared to translating traditional text. UGC is highly productive and exhibits various phenomena such as repeated characters, typographical errors, contractions, jargon, and unconventional sentence structures. These specificities lead to a significant number of Out-of-Vocabulary tokens (OOVs) and rare sequences, which pose problems since they are not adequately represented in the standard parallel corpora used to train MT models. Additionally, conventional domain adaptation techniques like fine-tuning have limited success in addressing these challenges. They suffer from performance degradation when applied to in-domain data and are unable to keep up with the ever-evolving nature of UGC.In this study, we focus on the task of automatically translating UGC in the zero-shot scenario, where we restrain from using any UGC-specific training data. Our aim is to develop more generalized MT architectures that can handle the distributional drift inherent in UGC. In the initial phase of our research, we dedicated our efforts to identifying and quantifying the specificities of UGC that hinder translation performance. We have also created evaluation frameworks and data collections to aid in this endeavor. Using off-the-shelf models, we investigate the challenges faced by MT systems when translating UGC and link the errors to their underlying mechanisms.Subsequently, we delve into the study and proposal of different methods to address the challenges posed by UGC. These methods include exploring normalization pipelines, employing more granular tokenization techniques, and utilizing latent variable models to enhance the robustness of MT systems. For each of these approaches, we systematically evaluate the performance and robustness of the systems, conduct a detailed error analysis, and offer insights into promising avenues for tackling the automatic translation of UGC in the zero-shot setting
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Eliasson, Daniel. "Game contingent claims." Thesis, KTH, Matematisk statistik, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-103080.
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Abstract Game contingent claims (GCCs), as introduced by Kifer (2000), are a generalization of American contingent claims where the writer has the opportunity to terminate the contract, and must then pay the intrinsic option value plus a penalty. In complete markets, GCCs are priced using no-arbitrage arguments as the value of a zero-sum stochastic game of the type described in Dynkin (1969). In incomplete markets, the neutral pricing approach of Kallsen and Kühn (2004) can be used. In Part I of this thesis, we introduce GCCs and their pricing, and also cover some basics of mathematical finance. In Part II, we present a new algorithm for valuing game contingent claims. This algorithm generalises the least-squares Monte-Carlo method for pricing American options of Longstaff and Schwartz (2001). Convergence proofs are obtained, and the algorithm is tested against certain GCCs. A more efficient algorithm is derived from the first one using the computational complexity analysis technique of Chen and Shen (2003). The algorithms were found to give good results with reasonable time requirements. Reference implementations of both algorithms are available for download from the author’s Github page https://github.com/del/ Game-option-valuation-library
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Economou, Theodoros. "Bayesian modelling of recurrent pipe failures in urban water systems using non-homogeneous Poisson processes with latent structure." Thesis, University of Exeter, 2010. http://hdl.handle.net/10036/111499.
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Recurrent events are very common in a wide range of scientific disciplines. The majority of statistical models developed to characterise recurrent events are derived from either reliability theory or survival analysis. This thesis concentrates on applications that arise from reliability, which in general involve the study about components or devices where the recurring event is failure. Specifically, interest lies in repairable components that experience a number of failures during their lifetime. The goal is to develop statistical models in order to gain a good understanding about the driving force behind the failures. A particular counting process is adopted, the non-homogenous Poisson process (NHPP), where the rate of occurrence (failure rate) depends on time. The primary application considered in the thesis is the prediction of underground water pipe bursts although the methods described have more general scope. First, a Bayesian mixed effects NHPP model is developed and applied to a network of water pipes using MCMC. The model is then extended to a mixture of NHPPs. Further, a special mixture case, the zero-inflated NHPP model is developed to cope with data involving a large number of pipes that have never failed. The zero-inflated model is applied to the same pipe network. Quite often, data involving recurrent failures over time, are aggregated where for instance the times of failures are unknown and only the total number of failures are available. Aggregated versions of the NHPP model and its zero-inflated version are developed to accommodate aggregated data and these are applied to the aggregated version of the earlier data set. Complex devices in random environments often exhibit what may be termed as state changes in their behaviour. These state changes may be caused by unobserved and possibly non-stationary processes such as severe weather changes. A hidden semi-Markov NHPP model is formulated, which is a NHPP process modulated by an unobserved semi-Markov process. An algorithm is developed to evaluate the likelihood of this model and a Metropolis-Hastings sampler is constructed for parameter estimation. Simulation studies are performed to test implementation and finally an illustrative application of the model is presented. The thesis concludes with a general discussion and a list of possible generalisations and extensions as well as possible applications other than the ones considered.
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Elfrgani, Aseim M. N. "Non-Foster Circuit Design and Stability Analysis for Wideband Antenna Applications." The Ohio State University, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=osu1431109155.
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