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1
Makkos, Joseph. "Recursive Loops". ScholarWorks@UNO, 2006. http://scholarworks.uno.edu/td/357.
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Taufer, Daniele. "Elliptic Loops". Doctoral thesis, Università degli studi di Trento, 2020. http://hdl.handle.net/11572/265846.
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Given an elliptic curve E over Fp and an integer e ≥ 1, we define a new object, called “elliptic loop”, as the set of plane projective points over Z/p^e Z lying over E, endowed with an operation inherited by the curve addition. This object is proved to be a power-associative abelian algebraic loop. Its substructures are investigated by means of other algebraic cubics defined over the same ring, which we named “shadow curve” and “layers”. When E has trace 1, a distinctive behavior is detected and employed for producing an isomorphism attack to the discrete logarithm on this family of curves. Stronger properties are derived for small values of e, which lead to an explicit description of the infinity part and to characterizing the geometry of rational |E|-torsion points.Data una curva ellittica E su Fp ed un intero e ≥ 1, definiamo un nuovo oggetto, chiamato "loop ellittico", come l'insieme dei punti nel piano proiettivo su Z/p^e Z che stanno sopra ad E, dotato di una operazione ereditata dalla somma di punti sulla curva. Questo oggetto si prova essere un loop algebrico con associatività delle potenze. Le sue sotto-strutture sono investigate utilizzando altre cubiche definite sullo stesso anello, che abbiamo chiamato "curva ombra" e "strati". Quando E ha traccia 1, un comportamento speciale viene notato e sfruttato per produrre un attacco di isomorfismo al problema del logaritmo discreto su questa famiglia di curve. Migliori proprietà vengono trovate per bassi valori di e, che portano ad una descrizione esplicita della parte all'infinito e alla caratterizzazione della geometria dei punti razionali di |E|-torsione.
3
Taufer, Daniele. "Elliptic Loops". Doctoral thesis, Università degli studi di Trento, 2020. http://hdl.handle.net/11572/265846.
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Given an elliptic curve E over Fp and an integer e ≥ 1, we define a new object, called “elliptic loop”, as the set of plane projective points over Z/p^e Z lying over E, endowed with an operation inherited by the curve addition. This object is proved to be a power-associative abelian algebraic loop. Its substructures are investigated by means of other algebraic cubics defined over the same ring, which we named “shadow curve” and “layers”. When E has trace 1, a distinctive behavior is detected and employed for producing an isomorphism attack to the discrete logarithm on this family of curves. Stronger properties are derived for small values of e, which lead to an explicit description of the infinity part and to characterizing the geometry of rational |E|-torsion points.Data una curva ellittica E su Fp ed un intero e ≥ 1, definiamo un nuovo oggetto, chiamato "loop ellittico", come l'insieme dei punti nel piano proiettivo su Z/p^e Z che stanno sopra ad E, dotato di una operazione ereditata dalla somma di punti sulla curva. Questo oggetto si prova essere un loop algebrico con associatività delle potenze. Le sue sotto-strutture sono investigate utilizzando altre cubiche definite sullo stesso anello, che abbiamo chiamato "curva ombra" e "strati". Quando E ha traccia 1, un comportamento speciale viene notato e sfruttato per produrre un attacco di isomorfismo al problema del logaritmo discreto su questa famiglia di curve. Migliori proprietà vengono trovate per bassi valori di e, che portano ad una descrizione esplicita della parte all'infinito e alla caratterizzazione della geometria dei punti razionali di |E|-torsione.
4
Spohr, Cristina. "Loops de Bol 2-nilpotentes e de expoente 2". Universidade de São Paulo, 2010. http://www.teses.usp.br/teses/disponiveis/45/45131/tde-16042010-133822/.
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Neste trabalho estudamos loops de Bol 2-nilpotentes e de expoente 2. Além disso, mostramos que o ideal de aumento de uma álgebra de loop, de um loop finito p-nilpotente em característica p > 0, é nilpotente. Com este resultado conseguimos caracterizar os elementos inversíveis da álgebra de loop de um loop 2-nilpotente sobre um corpo de dois elementos. Provamos também que loops de Bol finitos 2-nilpotentes e de expoente 2 podem ser mergulhados em um loop de Bol à direita de elementos inversíveis de uma álgebra alternativa à direita, sobre um corpo de característica dois.In this work we study 2-nilpotent Bol loops of exponent 2. Besides, we prove that the augmentation ideal of a loop algebra, of a finite p-nilpotent loop in characteristic p > 0, is nilpotent. With this result we characterized the invertible elements of the loop algebra of a 2-nilpotent loop over a field with two elements. We also proof that 2-nilpotent Bol loops of exponent 2 may be embedded into a right Bol loop of invertible elements of a right alternative algebra, over a field of characteristic 2.
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Mehraban, Mehrdad. "Instant Feedback Loops – for short feedback loops and early quality assurance". Thesis, Blekinge Tekniska Högskola, Institutionen för kommunikationssystem, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-13379.
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Context. In recent years, Software Quality Assurance (SQA) has become a crucial part of software development processes. Therefore, modern software development processes led to an increase in demand for manual and automated code quality assurance. Manual code quality reviews can be a time-consuming and expensive process with varying results. Thus, automated code reviews turn out to be a preferred alternative for mitigating this process. However, commercial and open-source static code analyzer tools often offer deep analysis with long lead time. Objectives. In this thesis work, the main aim is to introduce an early code quality assurance tool, which features a combination of software metrics. The tool should be able to examine code quality and complexity of a telecommunication grade software product such as source code of specific Ericsson product by Ericsson. This tool should encapsulate complexity and quality of a software product with regards to its efficiency, scope, flexibility, and execution time. Methods. For this purpose, the background section of the thesis is dedicated to in-depth research on software metrics included in well-known static code analyzers. Then, development environment, under investigation source code of Ericsson product, and collected software metric for evaluation were presented. Next, according to each software metric’s characteristics, point of interest, and requirement, a set of steps based on a Susman’s action research cycle were defined. Moreover, SWAT, a suitable software analytics toolkit, employed to extract conducted experiment data of each software metric from a static analyzer code named Lizard in order to detect most efficient software metrics. Outcome of conducted experiment demonstrates relationship of selected software metrics with one another. Results. The chosen software metrics were evaluated based on a variety of vital factors especially actual data from number of defects of specific Ericsson product. Highly effective software metrics from investigations in this thesis work were implemented as a new model named hybrid model to be utilized as an early quality assurance. Conclusions. The proposed model, which consist of well-performing software metrics, demonstrate an impressive performance as an early code quality indicator. Consequently, the utilized model in this master thesis could be studied in a future research to further investigate the effectiveness and robustness of this tool an early quality assurance.
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Gabrieli, Elisabetta. "Spiegelungsstrukturen und K-Loops". [S.l. : s.n.], 2000. http://www.sub.uni-hamburg.de/disse/113/inhalt.html.
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Stener, Mikael. "Moufang Loops : General theory and visualization of non-associative Moufang loops of order 16". Thesis, Uppsala universitet, Algebra och geometri, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-295889.
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Fernández, Fuentes Narcís. "Classification of loops in protein structures: applications on loop modeling and protein function". Doctoral thesis, Universitat Autònoma de Barcelona, 2004. http://hdl.handle.net/10803/3516.
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Aquesta tesis esta estructurada en cinc capítols. Al capítol I, es fa una introducció als llaços, el subjecte d'estudi d'aquesta tesis. A més, es fa una petita introducció a les bases de dades biològiques de us corrent i de protocols bio-informàtics en comparacions de seqüències. Del capítol II al IV s'explora el paper que els llaços juguen a les proteïnes utilitzant un enfocament bio-informàtic, es realitza una classificació estructural de llaços (capítol II); es realitza un estudi per inferir relacions d'estructura i funció (capítol III) i es realitza un estudi de predicció d'estructura de llaços (capítol IV). Finalment al capítol V es presenten unes consideracions finals al treball realitzat i es proposen futures extensions al mateix.El treball realitza per el Dr. Oliva ha sigut el punt d'inici d'aquesta tesis. Al capítol II es presenta un procés totalment automatitzat de classificació estructural de llaços de proteïnes quinases. Diferent millores varen ser introduïdes al treball original del Dr. Oliva: (i) un nou procés de reagrupació que evita els solapament entre agrupacions de llaços, (ii) un servidor web que permet l'accés i recerca de dades sobre els llaços classificats a través de internet, (iii) referències creuades amb altre bases de dades important. El capítol III es centra en dues qüestions bàsiques: la conservació de la estructura dels llaços i la seva funció i la conservació de la estructura dels llaços i la seva relació amb l'evolució. Un extensiu estudi sobre una classificació estructural de llaços de proteïnes quinases va ser realitzat. El motiu pe el quan les quinases varen ser escollides com a subjecte d'estudi es degut a la seva importància biològica i perquè hi ha molta informació disponible a la literatura. Finalment al capítol IV s'estudia la aplicabilitat de les classificacions estructurals de llaços en el camp de la predicció d'estructura. Es va realitzat un test de validació (Jack-knife test) per provar la utilitat de la informació de la seqüència en forma de perfils de les agrupacions estructurals de llaços.
This thesis is structured into five chapters. In chapter I, protein loops - the topics of this thesis work - are introduced. Also, a short description of biological databases and current protocols in sequence comparison are given. Chapters II to IV explore a major role that loop segments play in protein structures by using a structural bio-informatics approach: (i) the structural classification (ii) the relationship between the structure and function and (iii) the structure prediction of loops. The conclusive chapter V is devoted to several considerations that complement the conclusions given in previous chapters. Extensions of this thesis work are also suggested.
The research project on structural classification of loops, which was carried out by Dr. Oliva (Oliva et al. 1997), has been the starting point for all the other subsequent projects. In chapter II, a fully automated process for the structural classification of loops of kinases is presented. Several methodological improvements were made on the basis of Oliva's original work: (i) a newly introduced re-clustering process allows to avoid overlaps in classified loop clusters, (ii) a new web server was established to provide access and/or to query data through the internet, and (iii) cross referencing links were introduced with other biological databases. Chapter III focuses on two questions: the conservation of loop structures and functions and the extent of conservation of loop structures during evolution. An extensive analysis of a structural loop database of protein kinases was carried out. There are two main reasons why kinases were selected for the subject of this study: first, their critical biological relevance, and second the vast amount of functional information available in the literature and biological databases. Finally, in chapter IV, we apply ArchDB(Espadaler et al. 2004) for loop structure prediction. A Jack-knife test is performed to assess the usefulness of sequence information, which is included in the form of profiles in our structural clusters.
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Gowanlock, Graham Keith. "Impulse noise on telephone loops". Thesis, University of Ottawa (Canada), 1993. http://hdl.handle.net/10393/6611.
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Impulse noise is an ever increasing impediment to successful digital data transmission in the telephone local cable plant. Two major factors have caused this to happen. Firstly, remedies have been found for nearly all the other causes of signal degradation, such as crosstalk and intersymbol interference, leaving impulse noise outstanding. Secondly, the user's demand for higher and higher data rates and the proliferation of repeaterless operation at extended loop ranges, have made the effects of impulse noise more prominent. This thesis covers the subject of impulse noise in the local plant. It begins with experimental data obtained from field studies of the local loop segments of digital transmission systems. The theoretical aspects of impulse noise are next addressed, including the various methodologies for modeling it. Burst errors in the recovered data stream, and their relationship with impulse noise, their principal cause, are described. The methodologies for modeling burst errors are then discussed. Finally, the techniques for minimizing the harmful effects of impulse noise are examined. Included in this is a novel scheme, referred to as "Pulse Sharpening", now being introduced.
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Zhou, Yongxin. "Alternative algebras and RA loops". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape11/PQDD_0002/NQ42490.pdf.
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Horch, Alexander. "Condition Monitoring of Control Loops". Doctoral thesis, Stockholm : Tekniska högsk, 2000. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-3050.
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Blacklaw, Grant Andrew. "Permutations, loops and difference sets". Thesis, Royal Holloway, University of London, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.406303.
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Steer, Daniele Ann. "Thermal fields and cosmic loops". Thesis, Imperial College London, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.267263.
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Chintapalli, Sree Vamsee. "Closed loops in protein folding". Thesis, University of Essex, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.494193.
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Bordonalli, Aldario Chrestani. "Optical injection phase-lock loops". Thesis, University College London (University of London), 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.244183.
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Bauer, Sven. "Loops on real Stiefel-manifolds". Thesis, University of Aberdeen, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.367371.
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The central object of the study in this thesis is ΩO(n), the space of closed continuous loops on an orthogonal group O(n) based at the identity-element 1 Ε O(n). The space ΩO(n) carries a group structure given by pointwise multiplication of paths in the group O(n). This makes it an infinite dimensional Lie group. A filtration of ΩO(n), more precisely of the subspace of 'polynomial' loops, is constructed. This can be thought of as the 'real' analogue of the Mitchell-Richter filtration of ΩSU(n). Our filtration of ΩO(n) splits stably and O(n)-equivariantly in the cases n = 3, 4. We obtain: In contrast to the complex case no general splitting result can hold (this follows from work by Hopkins on stable indecomposability of ΩSp(2)). The thesis also investigates the topology of the loopspace of a real Stiefel-manifold. A stable O(n)-equivariant splitting for the fibrewise loop-space of a projective bundle is used to give a splitting for the free loop-space LRPn on a real projective space.
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Anjos, Giliard Souza dos. "Half-Isomorfismos de loops automórficos". Universidade de São Paulo, 2018. http://www.teses.usp.br/teses/disponiveis/45/45131/tde-03052018-221550/.
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Loops automórficos, ou A-loops, são loops nos quais todas as aplicações internas são automorfismos. Esta variedade de loops inclui grupos e loops de Moufang comutativos. Loops automórficos diedrais formam uma classe de A-loops construda a partir da duplicação de grupos abelianos finitos, generalizando a construção do grupo diedral. Outra classe de A-loops é a dos loops automórficos de Lie, construda a partir de anéis de Lie, definindo-se uma nova operação entre seus elementos. Um half-isomorfismo é uma bijeção f entre loops L e L\' onde, para quaisquer x e y pertencentes a L, temos que f(xy) pertence ao conjunto . Dizemos que o half-isomorfismo f é não trivial quando f não é um isomorfismo e nem um anti-isomorfismo. Nesta tese descrevemos propriedades de half-isomorfismos de loops, classificamos os half-isomorfismos entre loops automórficos diedrais e obtivemos o grupo de half-automorfismos nesta classe. Para os loops automórficos de Lie de ordem mpar, mostramos que todo half-automorfismo é trivial.Automorphic loops, or A-loops, are loops in which every inner mapping is an automorphism. This variety of loops includes groups and commutative Moufang loops. Dihedral automorphic loops form a class of A-loops, constructed from the duplication of finite abelian groups, that generalizes the construction of the dihedral group. Another class of A-loops is the Lie automorphic loops, constructed from Lie rings, where a new operation between its elements is defined. A half-isomorphism is a bijection f between loops L and L\' where, for any x and y belong to L, we have that f(xy) belongs to the set {f(x)f(y),f(y)f(x)}. We say that half-isomorphism f is non trivial when f is neither an isomorphism nor an anti-isomorphism. In this thesis, we describe properties of half-isomorphisms of loops, we classify the half-isomorphisms between dihedral automorphic loops and we obtain the group of half-automorphisms in this class. For the Lie automorphic loops of odd order, we show that every half-automorphism is trivial.
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FARIA, JUNIOR Joél. "Skew Loops e Superfícies Quádricas". reponame:Repositório Institucional da UNIFEI, 2017. http://repositorio.unifei.edu.br:8080/xmlui/handle/123456789/686.
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Submitted by repositorio repositorio (repositorio@unifei.edu.br) on 2017-03-15T18:01:49Z
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dissertacao_faria_junior_2017.pdf: 937266 bytes, checksum: 9969706623eab67e1e85bc07ef6bd2b1 (MD5)Made available in DSpace on 2017-03-15T18:01:49Z (GMT). No. of bitstreams: 1 dissertacao_faria_junior_2017.pdf: 937266 bytes, checksum: 9969706623eab67e1e85bc07ef6bd2b1 (MD5) Previous issue date: 2017-03
O objetivo deste trabalho é o estudo da relação entre skew loops e superfícies quádricas. Mostramos que as únicas superfícies do ℝ³ com um ponto onde a curvatura é positiva e que não possuem skew loops são as quádricas. Em particular: os elipsóides são as únicas superfícies fechadas sem skew loops.
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Allegro, Matteo. "Un'introduzione a quasigruppi e loops". Bachelor's thesis, Alma Mater Studiorum - Università di Bologna, 2012. http://amslaurea.unibo.it/4160/.
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Larsen, Kasper J. "Maximal Unitarity at Two Loops : A New Method for Computing Two-Loop Scattering Amplitudes". Doctoral thesis, Uppsala universitet, Teoretisk fysik, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-179203.
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The study of scattering amplitudes beyond one loop is necessary for precision phenomenology for the Large Hadron Collider and may also provide deeper insights into the theoretical foundations of quantum field theory. In this thesis we develop a new method for computing two-loop amplitudes, based on unitarity rather than Feynman diagrams. In this approach, the two-loop amplitude is first expanded in a linearly independent basis of integrals. The process dependence thereby resides in the coefficients of the integrals. These expansion coefficients are then the object of calculation. Our main results include explicit formulas for a subset of the integral coefficients, expressing them as products of tree-level amplitudes integrated over specific contours in the complex plane. We give a general selection principle for determining these contours. This principle is then applied to obtain the coefficients of integrals with the topology of a double box. We show that, for four-particle scattering, each double-box integral in the two-loop basis is associated with a uniquely defined complex contour, referred to as its master contour. We provide a classification of the solutions to setting all propagators of the general double-box integral on-shell. Depending on the number of external momenta at the vertices of the graph, these solutions are given as a chain of pointwise intersecting Riemann spheres, or a torus. This classification is needed to define master contours for amplitudes with arbitrary multiplicities. We point out that a basis of two-loop integrals with as many infrared finite elements as possible allows substantial technical simplications, in terms of obtaining the coefficients of the integrals, as well as for the analytic evaluation of the integrals themselves. We compute two such integrals at four points, obtaining remarkably compact expressions. Finally, we provide a check on a recently developed recursion relation for the all-loop integrand of the amplitudes of N=4 supersymmetric Yang-Mills theory, examining the two-loop six-gluon MHV amplitude and finding agreement. The validity of the approach to two-loop amplitudes developed in this thesis extends to all four-dimensional gauge theories, in particular QCD. The approach is suited for obtaining compact analytical expressions as well as for numerical implementations.
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Dang, Francis Hoai Dinh. "Speculative parallelization of partially parallel loops". [College Station, Tex. : Texas A&M University, 2007. http://hdl.handle.net/1969.1/ETD-TAMU-1271.
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Scott, Jason Terrence. "Multi-instrument observations of coronal loops". Diss., Montana State University, 2012. http://etd.lib.montana.edu/etd/2012/scott/ScottJ0512.pdf.
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This document exhibits results of analysis from data collected with multiple EUV satellites (SOHO, TRACE, STEREO, Hinode, and SDO). The focus is the detailed observation of coronal loops using multiple instruments, i.e. filter imagers and spectrometers. Techniques for comparing the different instruments and deriving loop parameters are demonstrated. Attention is given to the effects the different instruments may introduce into the data and their interpretation. The assembled loop parameters are compared to basic energy balance equations and scaling laws. Discussion of the blue-shifted, asymmetric, and line broadened spectral line profiles near the footpoints of coronal loops is made. The first quantitative analysis of the anti-correlation between intensity and spectral line broadening for isolated regions along loops and their footpoints is presented. A magnetic model of an active region shows where the separatrices meet the photospheric boundary. At the boundary, the spectral data reveal concentrated regions of increased blue-shifted outflows, blue wing asymmetry, and line broadening. This is found just outside the footpoints of bright loops. The intensity and line broadening in this region are anti-correlated. A comparison of the similarities in the spectroscopic structure near the footpoints of the arcade loops and more isolated loops suggests the notion of consistent structuring for the bright loops forming an apparent edge of an active region core.
23
Kurnik, Martin. "Protein folding without loops and charges". Doctoral thesis, Stockholms universitet, Institutionen för biokemi och biofysik, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-80512.
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Going down the folding funnel, proteins may sample a wide variety of conformations, some being outright detrimental to the organism. Yet, the vast majority of polypeptide molecules avoid such pitfalls. Not only do they reach the native minimum of the energy landscape; they do so via blazingly fast, biased, routes. This specificity and speed is remarkable, as the surrounding solution is filled to the brim with other molecules that could potentially interact with the protein and in doing so stabilise non-native, potentially toxic, conformations. How such incidents are avoided while maintaining native structure and function is not understood. This doctoral thesis argues that protein structure and function can be separated in the folding code of natural protein sequences by use of multiple partly uncoupled factors that act in a concerted fashion. More specifically, we demonstrate that: i) Evolutionarily conserved functional and regulatory elements can be excised from a present day protein, leaving behind an independently folded protein scaffold. This suggests that the dichotomy between functional and structural elements can be preserved during the course of protein evolution. ii) The ubiquitous charges on soluble protein surfaces are not required for protein folding in biologically relevant timescales, but are critical to intermolecular interaction. Monomer folding can be driven by hydrophobicity and hydrogen bonding alone, while functional and structural intermolecular interaction depends on the relative positions of charges that are not required for the native bias inherent to the folding mechanism. It is possible that such uncoupling reduces the probability of evolutionary clashes between fold and function. Without such a balancing mechanism, functional evolution might pull the carpet from under the feet of structural integrity, and vice versa. These findings have implications for both de novo protein design and the molecular mechanisms behind diseases caused by protein misfolding.At the time of the doctoral defense, the following paper was unpublished and had a status as follows: Paper 2: Manuscript.
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Rivera, Roberto Rafael. "On properties of completely flexible loops". Diss., Georgia Institute of Technology, 2000. http://hdl.handle.net/1853/28841.
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Robertson, David. "Transverse oscillations of interacting coronal loops". Thesis, University of Sheffield, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.538010.
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Serna, Martínez Pablo. "Simulaciones numéricas en modelos de loops". Doctoral thesis, Universidad de Murcia, 2014. http://hdl.handle.net/10803/146182.
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El objetivo de esta tesis consiste en el estudio de varias familias de modelos de loops en dos y tres dimensiones, donde se encuentran dos fases diferentes: una con loops finitos y otra donde hay al menos uno infinito. En concreto, se han estudiado tres clases de modelos de loops. El primero, un modelo de loops tridimensionales con orientación y color, definidos en redes con número de coordinación cuatro. El segundo, una modificación de estos modelos de loops que es un firme candidato a presentar una transición de fase de deconfinamiento. El tercero, un modelo de loops bidimensionales en la red cuadrada donde los loops pueden cruzarse. Hemos caracterizado el diagrama de fases de la primera familia de modelos en dos redes diferentes, las redes tridimensionales L y K. La transición de fase pasa a ser de primer orden a partir del valor n>nc, con cota inferior nc>3.0(2). Para n=1 y n=2 hemos mostrado que las clases de universalidad de los modelos de loops son las de la clase C de las transiciones de Anderson y la del modelo sigma sobre O(3), respectivamente. Esto es compatible con el hecho de que los modelos de loops se pueden expresar como una discretización de modelos sigma CP^{n-1}. Para n=3 los resultados son compatibles con transiciones de fase continuas en ambas redes, y hemos dado los exponentes críticos por primera vez: ν=0.536(13) y η=0.23(2). También hemos caracterizado la distribución de longitudes de loops en la fase extendida y es la de Poisson-Dirichlet con parámetro θ=n. En la segunda clase de modelos, para n=2 hemos podido describir una transición entre la fase extendida y una fase localizada, fase U(1), que cambia mediante un crossover a la fase localizada Z_4. Hemos mostrado que este modelo se comporta de forma similar a los modelos paradigmáticos para el estudio de la criticalidad cuántica de deconfinamiento y parece estar en la misma clase de universalidad. Hemos hecho varias propuestas y podemos destacar que los resultados son compatibles con una transición continua no estándar o una de primer orden muy débil. Damos también estimaciones de los exponentes críticos a partir de varios observables. Hemos propuesto un candidato a mostrar un punto crítico de deconfinamiento, relacionado con sistemas magnéticos SU(2), y hemos estudiados tamaños mayores que los que se han publicado hasta ahora. Por último, hemos estudiado los modelos de loops bidimensionales con cruces. Hemos podido determinar las características de la llamada fase de Goldstone, en particular el comportamiento logarítmico de varios observables: correlaciones, distribución de longitudes, etc. Para conseguir estudiar esto, hemos desarrollado una técnica paralelizable de matriz de transferencia que ha permitido el acceso a tamaños enormes. También hemos caracterizado la transición de fase y hemos proporcionado los valores de los exponentes críticos. Estos exponentes son muy similares a los de la clase simpléctica de las transiciones de Anderson en 2D. El estudio de estos tres modelos se ha realizado mediante simulaciones numéricas y para ello hemos usado varios algoritmos basados en procesos de Monte Carlo. La implementación de los algoritmos se ha hecho en FORTRAN 90, con el uso de bibliotecas para la paralelización como OPENMP y MPICH. También se ha desarrollado una implementación en el lenguaje para procesadores gráficos programables: CUDA. Con este trabajo hemos mostrado una forma diferente de estudiar transiciones de fase cuánticas, mediante la simulación de modelos geométricos (clásicos). Ésto permite el acceso a tamños mucho mayores que otro tipo de técnicas.The work in this thesis is devoted to the study of loop models in two and three dimensions, where there are two different phases: one with finite loops, and the other with at least one infinite loop. Specifically, three families of loop models have been studied. First, a family of three-dimensional completely-packed loop models with n colors, where the loops are defined in four-coordinated, oriented lattices. Second, the same family of loop models when there is an extra interaction that preserves an special symmetry of the lattice. Third, a family of two-dimensional completely-packed loop models where the loops are allowed to cross. We have characterised the phase diagram of the first family of models in two different lattices, the three-dimensional L and K lattices. The character of the phase transitions becomes first order for n>nc and we have presented a lower bound: nc>3.0(2). For n=1 and n=2 we have shown that the universality classes of the loop models are those of the class C at the Anderson transitions and the O(3) sigma model, respectively. This is compatible with the fact that the loop models can be related to a lattice field theory of the CP^{n-1} sigma models. For n=3 we have found results compatibles with a continuous phase transition for both lattices, and we have given for the first time values of the critical exponents: ν=0.536(13) and η=0.23(2). We have also characterised the loop length distribution of the extended phase and we have found that it is the Poisson-Dirichlet distribution with parameter θ=n. In the second model, for n=2 we have been able to describe a transition between the extended phase and a localised phase, the so-called U(1) phase, which crossover to a Z_4 localised phase. We have shown that this model behaves similarly to the paradigmatic models for the study of the quantum deconfinement criticality and seems to be in that universality class. We would like to emphasize that the results are compatible with a "non-standard" continuous transition or a very weak first order transition. We have proposed a candidate to show a deconfined critical point, related to SU(2) magnets, and we have studied system sizes bigger than what have been published up to date. And last, we have also studied the bidimensional loop models with crossings. We have been able to pin down the features of the so-called Goldstone phase. Particularly, we have found logarithmic behaviours in several observables: correlators, winding number, etc. In order to observe them we have developed a parallelizable transfer matrix technique which has allowed us to reach enormous system sizes. We have also studied the phase transition in these models and we have characterised the critical exponents for the first time. We have found that they are quite similar to those of the symplectic class of Anderson transition in two dimensions. We have performed the study of these loop models by numerical procedures, using several Monte Carlo algorithms. The implementation of these algorithms have been done in FORTRAN 90 with the parallelization libraries: OPENMP and MPICH. We have also developed an implementation of one of these algorithms in graphical processing units with CUDA. With this work we have given a different approach to study of several quantum phase transitions by simulating geometrical (classical) models, which allows to study system sizes bigger than other techniques.
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Garreau-Iles, Angelique Genevieve Lucie. "Triblock copolymers : the quest for loops". Thesis, University of Bristol, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.394068.
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Dean, John Scott. "An Aspect Pointcut for Parallelizable Loops". NSUWorks, 2013. http://nsuworks.nova.edu/gscis_etd/131.
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This study investigated the need for a pointcut for parallelizable loops in an aspect-oriented programming environment. Several prototype solutions exist for loop pointcuts, but the solutions are not very granular. In particular, they are not able to differentiate between loops that are parallelizable and those that are not. Being able to identify parallelizable loops automatically, as part of an aspect-oriented compiler's weaving process, is particularly important because (1) manually identifying parallelizable loops is known to be a difficult problem and (2) aspectizing parallelized loops can lead to a reduction in code tangling and an increase in separation of concerns.
This paper describes the concepts behind the loop-pointcut problem. It then describes the approach used in this study for implementing a solution in the form of an aspect-oriented Java compiler with a parallelizable loop pointcut. Identifying parallelizable loops is known to be a difficult problem, and as such, this study's parallelizable loop pointcut implements a heuristic solution. The pointcut identifies many parallelizable loops as being parallelizable, but in erring on the side of conservatism, there are some parallelizable loops that the pointcut is unable to identify as parallelizable.
To test the parallelizable-loop pointcut, the pointcut was applied to a benchmark set of parallelizable programs. There were two versions of each benchmark program - (1) an aspect-oriented version, where the aspect-oriented compiler's weaver added the multi-threading functionality, and (2) a non-aspect-oriented version, where the benchmark program's source code directly implemented the multi-threading functionality. For each benchmark program, the output from the aspect-oriented version was compared to the output from the non-aspect-oriented version. The study found that each loop that was deemed parallelizable by the aspect-oriented benchmark program was executed in parallel (with multiple threads) by both versions of the program - the aspect-oriented version and the non-aspect-oriented version. There were some loops in the non-aspect-oriented benchmark programs that were deemed parallelizable and executed in parallel, but those same loops were deemed non-parallelizable by their associated aspect-oriented benchmark program. This discrepancy is explained by the study's conservative approach to identifying loops as parallelizable.
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Yeomans, Maria Elena Tejeda. "Parton-parton scattering at two-loops". Thesis, Durham University, 2001. http://etheses.dur.ac.uk/3773/.
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We present an algorithm for the calculation of scalar and tensor one- and two-loop integrals that contribute to the virtual corrections of 2 →2 partonic scattering. First, the tensor integrals are related to scalar integrals that contain an irreducible propagator-like structure in the numerator. Then, we use Integration by Parts and Lorentz Invariance recurrence relations to build a general system of equations that enables the reduction of any scalar integral (with and without structure in the numerator) to a basis set of master integrals. Their expansions in e = 2-D/2 have already been calculated and we present a summary of the techniques that have been used to this end, as well as a compilation of the expansions we need in the different physical regions. We then apply this algorithm to the direct evaluation of the Feynman diagrams contributing to the O(α4/8) one- and two-loop matrix-elements for massless like and unlike quark-quark, quark-gluon and gluon-gluon scattering. The analytic expressions we provide are regularised in Convensional Dimensional Regularisation and renormalised in the MS scheme. Finally, we show that the structure of the infrared divergences agrees with that predicted by the application of Catani's formalism to the analysis of each partonic scattering process. The results presented in this thesis provide the complete calculation of the one- and two-loop matrix-elements for 2 2 processes needed for the next-to-next-to-leading order contribution to inclusive jet production at hadron colliders.
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Blasi, Junior Francisco. "Otimização em loops no Projeto Xingo". [s.n.], 2005. http://repositorio.unicamp.br/jspui/handle/REPOSIP/276316.
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Orientador: Rodolfo Jardim de AzevedoDissertação (mestrado profissional) - Universidade Estadual de Campinas, Instituto de Computação
Made available in DSpace on 2018-08-05T13:01:34Z (GMT). No. of bitstreams: 1 BlasiJunior_Francisco_M.pdf: 934725 bytes, checksum: 6a13eaaaee52e0aabb1a74f3c2c4669f (MD5) Previous issue date: 2005
Resumo: As otimizações implementadas em compiladores proporcionam uma melhora significativa de desempenho dos programas. Em muitos casos, proporcionam também a redução do tamanho do programa. Quase todos os programas em produção são compilados com diretivas de otimização, para obter máximo desempenho.Para o estudo de novas técnicas de otimização, faz-se necessário um ambiente de testes no qual essas técnicas possam ser incorporadas facilmente. O projeto Xingó foi desenvolvido com esse intuito. Gerando código C compilável, o Xingó proporciona facilmente a verificação do resultado das otimizações implementadas.Este trabalho mostra a implementa¸c¿ao de algumas otimizações em loops no projeto Xingó, demonstrando a viabilidade de novas otimizações serem incorporadas. Além disso, este trabalho analisa o resultado da utiliza¸c¿ao de ferramentas disponíveis no mercado que verificam a corretude de cada uma das otimizações e que avaliam o desempenho do sistema com as otimizações implementadas
Abstract: Software performance is signifcantly improved by the optimizations implemented on the compilers. In some cases, the compiler optimizations also reduces the size of the software.It is necessary to have a test environment in order to study the result of optimization technics. The Xingó project was developed with such a concept in mind. By generating C compilable code, Xingó allows easy visualization of the results of new optimization technics.This work shows the implementation of some loop optimizations on the Xingó project, demonstrating that it can incorporate new optimizations. Besides that, this work shows the results from the usage of available tools that checks each optimization correctness and also tools that analyses the performance of the system with the optimizations incorporated.
Mestrado
Engenharia de Computação
Mestre em Computação
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Pires, Rosemary Miguel. "Loops de código: automorfismos e representações". Universidade de São Paulo, 2011. http://www.teses.usp.br/teses/disponiveis/45/45131/tde-10072011-093023/.
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Neste trabalho, estudamos Loops de Código. Para este estudo, introduzimos os loops de código a partir de códigos pares e depois, provamos que loops de código de posto $n$ podem ser caracterizados como imagem homomórfica de certos loops de Moufang livres com n geradores. Além disso, introduzimos o conceito de vetores característicos associados a um loop de código. Com os resultados da teoria estudada, classificamos todos os loops de código de posto 3 e 4, encontramos todos os grupos de automorfismos externos destes loops e, finalmente, determinamos todas as suas respectivas representações básicas.This work is about code loops. For this study, we introduce the code loops from even codes and then we prove that code loops of rank n can be characterized as a homomorphic image of a certain free Moufang loops with $n$ generators. Moreover, we introduce the concept of characteristic vectors associated with code loops. With the results of this theory, we classify all the code loops of rank 3 and 4, we find all the groups of outer automorphisms of these loops and finally we determine all their basic representations.
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Reis, Márcio Alexandre de Oliveira. "Loops de Bol algébricos e analíticos". Universidade de São Paulo, 2010. http://www.teses.usp.br/teses/disponiveis/45/45131/tde-27062010-143306/.
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Neste trabalho classificamos, a menos de isomorfismos, as álgebras de Bol de dimensão 2 sobre um corpo de característica 0. Também determinamos suas álgebras de Lie envolvente e, mostramos que existem álgebras de Bol não isomorfas cujas álgebras de Lie envolventes coorrespondentes são isomorfas. Calculamos os grupos algébricos (locais) correspondentes a cada uma das álgebras de Lie envolventes e provamos que todo loop de Bol analítico (algébrico) global de dimensão 2 sobre um corpo de característica 0 é um grupo. Exibimos exemplos de loops de Bol algébricos globais de dimensão n, para todo n > 2, e fornecemos uma condição necessária e suciente para a existência de um loop de Bol algébrico global quando a álgebra de Bol tem uma álgebra de Lie envolvente nilpotente de índice 2 sobre um corpo de característica diferente de 2.In this work, we classify up to isomorphism, the Bol algebras of dimension 2 over a eld of characteristic 0. We also determine their enveloping Lie algebras and we exhibit two non-isomorphic Bol algebras which have isomorphic enveloping Lie algebras. We determine the (local) correspondent algebraic groups of each of those enveloping Lie algebras and we show that every global analytic (algebraic) Bol loop of dimension 2 over a eld of characteristic 0 is a group. We exhibit examples of non-nilpotent solvable algebraic Bol loops in dimension n for every n > 2, and we were able to give a necessary and sucient condition to decide if a local algebraic Bol loop is global when its enveloping Lie algebra is nilpotent of index 2 and char(F) 6= 2:
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Anjos, Giliard Souza dos. "Grupo de automorfismos de A-loops". reponame:Repositório Institucional da UFABC, 2014.
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GOMEZ, CAROLINA VALERIA. "Wilson loops in supersymmetric gauge theories". Doctoral thesis, Università degli Studi di Milano-Bicocca, 2020. http://hdl.handle.net/10281/258696.
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This thesis is dedicated to the study of Wilson loops in supersymmetric gauge theories, we will study their properties and how they are related to physical observables, such as the Bremsstrahlung function that controls to the energy radiated by an accelerating particle. We will give various examples of the computation of their expectations values using perturbative and non-perturbative techniques. For SU(N) superconformal QCD we perform a three-loop calculation of the generalized cusp anomalous dimension of the BPS Wilson loop operator using HQET formalism. We obtain an expression which is valid at generic geometric and internal angles and finite gauge group rank N. For equal and opposite angles this expression vanishes, proving that at these points the cusp becomes BPS. From its small angle expansion we derive the corresponding Bremsstrahlung function at three loops, matching the matrix model prediction given in terms of derivatives of the Wilson loop on the ellipsoid.This thesis is dedicated to the study of Wilson loops in supersymmetric gauge theories, we will study their properties and how they are related to physical observables, such as the Bremsstrahlung function that controls to the energy radiated by an accelerating particle. We will give various examples of the computation of their expectations values using perturbative and non-perturbative techniques. For SU(N) superconformal QCD we perform a three-loop calculation of the generalized cusp anomalous dimension of the BPS Wilson loop operator using HQET formalism. We obtain an expression which is valid at generic geometric and internal angles and finite gauge group rank N. For equal and opposite angles this expression vanishes, proving that at these points the cusp becomes BPS. From its small angle expansion we derive the corresponding Bremsstrahlung function at three loops, matching the matrix model prediction given in terms of derivatives of the Wilson loop on the ellipsoid.
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Fili, Thomas. "Studio, implementazione e test di phase-locked loops per segnali "open loop" da sonde interplanetarie". Bachelor's thesis, Alma Mater Studiorum - Università di Bologna, 2017. http://amslaurea.unibo.it/14372/.
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La tesi tratta di studio, test ed implementazione di Phase-Locked Loops, ovvero sistemi di controllo automatico il cui obiettivo è rigenerare segnali di telecomunicazione di input soggetti a jitter di fase.
Dalla definizione delle trasformate di Laplace del controllore si passa all'implementazione delle analoghe equazioni in tempo discreto (z-transform) in Matlab & Simulink per studiare il comportamento di questi sistemi con segnali sintetici e reali (provenienti dalla sonda Juno).
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Wu, Chia-Ying (Charles). "Musical and Dramatic Functions of Loops and Loop Breakers in Philip Glass's Opera The Voyage". Thesis, University of North Texas, 2016. https://digital.library.unt.edu/ark:/67531/metadc849734/.
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Philip Glass's minimalist opera The Voyage commemorates the 500th Anniversary of Christopher Columbus's discovery of America. In the opera, Philip Glass, like other composers, expresses singers' and non-singers' words and activities by means of melodies, rhythms, chords, textures, timbres, and dynamics. In addition to these traditional musical expressions, successions of reiterating materials (RMs, two or more iterations of materials) and non reiterating materials (NRMs) become new musical expressions. However, dividing materials into theses two categories only distinguishes NRMs from RMs without exploring relations among them in successions. For instance, a listener cannot perceive the functional relations between a partial iteration of the RM and the NRM following the partial RM because both the partial RM and the NRM are NRMs. As a result, a listener hears a succession of NRM followed by another NRM. When an analyst relabels the partial RM as partial loop, and the NRM following the partial RM as loop breaker, a listener hears the NRM as a loop breaker causing a partial loop. The musical functions of loops and loop breakers concern a listener's expectations of the creation, sustaining, departure, and return to the norm in successions of loops and loop breakers. When a listener associates the satisfaction and dissatisfaction of these expectations with dramatic devices such as incidents, words in dialogues and soliloquies, and activities by singers and non-singers, loops and loop breakers in successions become dramatically functional. This dissertation explores the relations among musical and dramatic functions of loops and loop breakers in Glass's musical commemoration of Columbus.
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Souder, William Dai Foster. "A low power 10 GHz phase locked loop for radar applications implemented in 0.13 um SiGe technology". Auburn, Ala, 2009. http://hdl.handle.net/10415/1631.
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Li, Xiang, i xiali@cs rmit edu au. "Utilising Restricted For-Loops in Genetic Programming". RMIT University. Computer Science and Information Technology, 2007. http://adt.lib.rmit.edu.au/adt/public/adt-VIT20080110.122751.
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Genetic programming is an approach that utilises the power of evolution to allow computers to evolve programs. While loops are natural components of most programming languages and appear in every reasonably-sized application, they are rarely used in genetic programming. The work is to investigate a number of restricted looping constructs to determine whether any significant benefits can be obtained in genetic programming. Possible benefits include: Solving problems which cannot be solved without loops, evolving smaller sized solutions which can be more easily understood by human programmers and solving existing problems quicker by using fewer evaluations. In this thesis, a number of explicit restricted loop formats were formulated and tested on the Santa Fe ant problem, a modified ant problem, a sorting problem, a visit-every-square problem and a difficult object classification problem. The experimental results showed that these explicit loops can be success fully used in genetic programming. The evolutionary process can decide when, where and how to use them. Runs with these loops tended to generate smaller sized solutions in fewer evaluations. Solutions with loops were found to some problems that could not be solved without loops. The results and analysis of this thesis have established that there are significant benefits in using loops in genetic programming. Restricted loops can avoid the difficulties of evolving consistent programs and the infinite iterations problem. Researchers and other users of genetic programming should not be afraid of loops.
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Saksena, Mayank. "Verifying Absence of ∞ Loops in Parameterized Protocols". Doctoral thesis, Uppsala University, Department of Information Technology, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-8605.
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The complex behavior of computer systems offers many challenges for formal verification. The analysis quickly becomes difficult as the number of participating processes increases.
A parameterized system is a family of systems parameterized on a number n, typically representing the number of participating processes. The uniform verification problem — to check whether a property holds for each instance — is an infinite-state problem. The automated analysis of parameterized and infinite-state systems has been the subject of research over the last 15–20 years. Much of the work has focused on safety properties. Progress in verification of liveness properties has been slow, as it is more difficult in general.
In this thesis, we consider verification of parameterized and infinite-state systems, with an emphasis on liveness, in the verification framework called regular model checking (RMC). In RMC, states are represented as words, sets of states as regular expressions, and the transition relation as a regular relation.
We extend the automata-theoretic approach to RMC. We define a specification logic sufficiently strong to specify systems representable using RMC, and linear temporal logic properties of such systems, and provide an automatic translation from a specification into an analyzable model.
We develop acceleration techniques for RMC which allow more uniform and automatic verification than before, with greater power. Using these techniques, we succeed to verify safety and liveness properties of parameterized protocols from the literature.
We present a novel reachability based verification method for verification of liveness, in a general setting. We implement the method for RMC, with promising results.
Finally, we develop a framework for the verification of dynamic networks based on graph transformation, which generalizes the systems representable in RMC. In this framework we verify the latest version of the DYMO routing protocol, currently being considered for standardization by the IETF.
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Terlemez, Bortecene. "Oscillation Control in CMOS Phase-Locked Loops". Diss., Georgia Institute of Technology, 2004. http://hdl.handle.net/1853/4841.
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Recent advances in voltage-controlled oscillator (VCO) design and the trend of CMOS processing indicate that the oscillator control is quickly becoming one of the forefront problems in high-frequency and low-phase-noise phase-locked loop (PLL) design. This control centric study explores the limitations and challenges in high-performance analog charge-pump PLLs when they are extended to multiple gigahertz applications.
Several problems with performance enhancement and precise oscillator control using analog circuits in low-voltage submicron CMOS processes, coupled with the fact that analog (or semi-digital) oscillators having various advantages over their digitally controlled counterparts, prompted the proposal of the digitally-controlled phase-locked loop. This research, then, investigates a class of otherwise analog PLLs that use a digital control path for driving a current-controlled oscillator. For this purpose, a novel method for control digitization is described where trains of pulses code the phase/frequency comparison information rather than the duration of the pulses: Pulse-Stream Coded Phase-Locked Loop (psc-PLL).
This work addresses issues significant to the design of future PLLs through a comparative study of the proposed digital control path topology and improved cutting-edge charge-pump PLLs.
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Myllylä, K. (Kari). "On the solvability of groups and loops". Doctoral thesis, University of Oulu, 2003. http://urn.fi/urn:isbn:9514269055.
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Abstract
The dissertation consists of three articles in which the solvability of groups and the solvability of loops are considered. The first parts of the thesis survey some basic information and results on transversals and loops. The summarizing parts provide the three main results for the solvability of groups and loops.
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Berndtsson, Magnus. "Fault detection in lambda-tuned control loops". Licentiate thesis, Luleå : Luleå University of Technology, 2006. http://epubl.ltu.se/1402-1757/2006/47/LTU-LIC-0647-SE.pdf.
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Hennion, Benjamin. "Formal loops spaces and tangent Lie algebras". Thesis, Montpellier, 2015. http://www.theses.fr/2015MONTS160/document.
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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 lissitéIf 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
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Kling, Michael (Michael W. ). "Detecting and escaping infinite loops using Bolt". Thesis, Massachusetts Institute of Technology, 2012. http://hdl.handle.net/1721.1/77024.
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Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2012.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 89-91).
In this thesis we present Bolt, a novel system for escaping infinite loops. If a user suspects that an executing program is stuck in an infinite loop, the user can use the Bolt user interface, which attaches to the running process and determines if the program is executing in an infinite loop. If that is the case, the user can direct the interface to automatically explore multiple strategies to escape the infinite loop, restore the responsiveness of the program, and recover useful output. Bolt operates on stripped x86 and x64 binaries, analyzes both single-thread and multi-threaded programs, dynamically attaches to the program as-needed, dynamically detects the loops in a program and creates program state checkpoints to enable exploration of different escape strategies. This makes it possible for Bolt to detect and escape infinite loops in off-the-shelf software, without available source code, or overhead in standard production use.
by Michael Kling.
M.Eng.
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Durant, Kevin. "Investigating the non-termination of affine loops". Thesis, Stellenbosch : Stellenbosch University, 2013. http://hdl.handle.net/10019.1/80052.
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Thesis (MSc)--Stellenbosch University, 2013.ENGLISH ABSTRACT: The search for non-terminating paths within a program is a crucial part of software verification, as the detection of anfinite path is often the only manner of falsifying program termination - the failure of a termination prover to verify termination does not necessarily imply that a program is non-terminating. This document describes the development and implementation of two focussed techniques for investigating the non-termination of affine loops. The developed techniques depend on the known non-termination concepts of recurrent sets and Jordan matrix decomposition respectively, and imply the decidability of single-variable and cyclic affine loops. Furthermore, the techniques prove to be practically capable methods for both the location of non-terminating paths, as well as the generation of preconditions for non-termination.
AFRIKAANSE OPSOMMING: Sagtewareveri kasie vereis of die bewys van die beeindiging van 'n program, of die deteksie van oneindige uitvoerings. In hierdie tesis ontwikkel en implementeer ons twee tegnieke om oor die oneindige eienskap van a ene lusse te beslis. Die tegnieke wat ontwikkel word is gebaseer op konsepte soos Jordan matriksdekomposisie en herhaalde groepe wat al in die verlede gebruik is om die beeindiging van lusse te ondersoek. Die tegnieke kan gebruik word om die uitvoerbaarheid van beide een-veranderlike en sikliese a ene lusse te bepaal. Feitlik alle nie-eindige a ene lusse kan ge denti seer word en die toestande waaronder hierdie oneindige eienskap verskyn kan beskryf word.
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Mikkelson, Rana Catherine. "Minimum rank of graphs that allow loops". [Ames, Iowa : Iowa State University], 2008.
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Högstedt, Karin Dyveke. "Predicting performance for tiled perfectly nested loops /". Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 1999. http://wwwlib.umi.com/cr/ucsd/fullcit?p9951422.
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Ko, Byung-su. "On performance assessment of feedback control loops /". Digital version accessible at:, 2000. http://wwwlib.umi.com/cr/utexas/main.
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Williamson, Alastair. "Time-dependent resonant damping in coronal loops". Thesis, University of Sheffield, 2013. http://etheses.whiterose.ac.uk/4803/.
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This Thesis will extend the current theory of propagating, linear MHD waves into a cylindrical model containing a time-dependent background density. The current observations of propagating waves in the solar corona clearly show that the magnetic waveguides contain many time-dependent features which have, to date, been excluded from the majority of theoretical models investigating MHD wave propagation. Analysing a straight magnetic flux tube, to leading order in the WKB approximation, allows for the derivation of two governing equations describing the perturbed total pressure and the radial displacement. These governing equations allow for the formation of the general dispersion relation and, taking the thin-tube limit, a full expression for the wave phase can be determined. Using the wave phase, it is possible to calculate the dynamic frequency, dynamic wavenumber and amplitude of the various wave modes and then the temporal evolution of these quantities can be explored. By introducing a thin annular layer, smoothly joining the interior and exterior of the flux tube, an investigation into the resonant damping of the propagating MHD waves can be conducted. Analytical expressions for the resonant jump conditions and the damping coefficient for the fast MHD wave can be found and their temporal evolution explored.
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Scott, Amy. "Transverse oscillations of non-planar coronal loops". Thesis, University of Sheffield, 2012. http://etheses.whiterose.ac.uk/3213/.
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In this thesis a non-planar coronal loop model is introduced. The loop has helical geometry and therefore has non-zero curvature and torsion. A curvilinear coordinate system is introduced, which uses the loop axis as a coordinate line and the loop boundary as a coordinate surface. We assume that the density along the loop is stratified. The governing equation for kink oscillations of the loop is derived under the assumption of the thin tube approximation. It is found that the governing equation has the same form as the governing equation for a straight loop with density varying along the tube. Therefore we find that the curvature and torsion do not directly affect the eigenfrequencies, although they still affect the eigenfrequencies indirectly through modifying the density profile along the loop. The main effect of the loop torsion is that it alters the polarization of the oscillation. We find that, for a loop with non-zero torsion, the direction of polarization rotates with the principal normal as we move along the loop. Observational signatures of kink oscillations of a non-planar loop are discussed. We also investigate whether the non-planarity of a loop has any effect on the results of coronal seismology. We consider two seismological applications: the estimate of the density scale height in the corona using the ratio of the periods of the fundamental harmonic and first overtone of kink oscillations, and the estimate of the magnetic field strength obtained from the period of the fundamental harmonic and the loop length. We show that the non-planarity of the loop does not affect the period ratio, and therefore does not change estimates of the density scale height, and we find that density stratification and loop non-planarity only have a weak effect on estimates of the magnetic field strength.