One of the main objectives of software development in scientific computing is efficiency. Being focused on highly specialized application domain, important software quality metrics, e.g., usability, extensibility ,etc may not be amongst the list of primary objectives. In this research, we have studied the design structures and iterative releases of scientific research software using Design Structure Matrix(DSM). We implemented a DSM partitioning algorithm using sparse matrix data structure Compressed Row Storage(CRS), and its timing was better than those obtained from the most widely used C++ library boost. Secondly, we computed several architectural complexity metrics, compared releases and total release costs of a number of open source scientific research software. One of the important finding is the absence of circular dependencies in studied software which attributes to the strong emphasis on computational performance of the code. Iterative release analysis indicates that there might be a correspondence between “clustering co-efficient” and “release rework cost” of the software. / x, 87 leaves : ill. ; 29 cm

It was conjectured in the early 1950¡¯s that the empirical spectral distribution (ESD) of an $n \times n$ matrix whose entries are independent and identically distributed with mean zero and variance one, normalized by a factor of $\frac{1}{\sqrt{n}}$, converges to the uniform distribution over the unit disk on the complex plane, which is called the circular law. The goal of this thesis is to prove the so called Replacement Principle introduced by Tao and Vu which is a crucial step in their recent proof of the circular law in full generality. It gives a general criterion for the difference of the ESDs of two normalised random matrices $\frac{1}{\sqrt{n}}A_n$, $\frac{1}{\sqrt{n}}B_n$ to converge to 0. / Thesis (Master, Mathematics & Statistics) -- Queen's University, 2009-07-11 14:57:44.225

No description available.

The character table of any finite group provides a considerable amount of information about a group and the use of character tables is of great importance in Mathematics and Physical Sciences. Most of the maximal subgroups of finite simple groups and their automorphisms are extensions of elementary abelian groups. Various techniques have been used to compute character tables, however Bernd Fischer came up with the most powerful and informative technique of calculating character tables of group extensions. This method is known as the Fischer-Clifford Theory and uses Fischer-Clifford matrices, as one of the tools, to compute character tables. This is derived from the Clifford theory. Here G is an extension of a group N by a finite group G, that is G = N.G. We then construct a non-singular matrix for each conjugacy class of G/N =G. These matrices, together with partial character tables of certain subgroups of G, known as the inertia groups, are used to compute the full character table of G. In this dissertation, we discuss Fischer-Clifford theory and apply it to both split and non-split extensions. We first, under the guidance of Dr Mpono, studied the group 27:S8 as a maximal subgroup of 27:SP(6,2), to familiarize ourselves to Fischer-Clifford theory. We then looked at 26:A8 and 28:O+8 (2) as maximal subgroups of 28:O+8 (2) and O+10(2) respectively and these were both split extensions. Split extensions have also been discussed quite extensively, for various groups, by different researchers in the past. We then turned our attention to non-split extensions. We started with 24.S6 and 25.S6 which were maximal subgroups of HS and HS:2 respectively. Except for some negative signs in the first column of the Fischer-Clifford matrices we used the Fisher-Clifford theory as it is. The Fischer-Clifford theory, is also applied to 53.L(3, 5), which is a maximal subgroup of the Lyon's group Ly. To be able to use the Fisher-Clifford theory we had to consider projective representations and characters of inertia factor groups. This is not a simple method and quite some smart computations were needed but we were able to determine the character table of 53.L(3,5). All character tables computed in this dissertation will be sent to GAP for incorporation. / Thesis (Ph.D.)-University of KwaZulu-Natal, Pietermaritzburg, 2011.

Thèse numérisée par la Division de la gestion de documents et des archives de l'Université de Montréal

The potential of filling carbon nanotubes in polymers has been widely acknowledged for composites with exceptional new properties owing to the high strength of carbon nanotubes. In the thesis, by employing Materials Studio 4.0 software, the buckling behaviour and vibration of polyethylene and carbon nanotube matrix composites are first discussed using molecular mechanics simulations. The research is aimed to acquire a high strength design of PE-CNT matrix with proper PE/CNT ratio as well as discovering the dynamic characteristics of the PE-CNT composites. Investigation results show that as the number of PE chains increases, the buckling strain and the resonance frequency will decrease. Van der Waals forces are collected to explain the relation of the PE chains to the buckling strain and the resonance frequency of the composites.

Kompleksinės sistemos pasižymi naujomis savybėmis, kurias neįmanoma prognozuoti tiriant atskirus tų sistemų elementus. Buvo pastebėta, kad žinomi nesudėtingų sistemų analizės metodai yra neadekvatūs naujiems uždaviniams, neatsako į užduodamus klausimus, todėl kompleksinėms sistemoms analizuoti reikia kurti naujus metodus. Kompleksinių sistemų teorija yra palyginti nauja teorija ir viena iš pagrindinių jos taikymo sričių yra žmogaus organizmo funkcinės būklės vertinimo, mokslinių hipotezių tikrinimo, naujų žinių paieškos uždaviniai. Pasirinkta darbo tematika neabejotinai yra aktuali šiandienos teorijai ir praktikai. Darbe buvo nagrinėjami šeši elektrokardiografiniai parametrai: trukminiai RR-DQRS-DJTp ir amplitudiniai AR-AT1-ATS2. Iš parametrų skirtumų sudaromos matricų sekos ir skaičiuojami invariantiniai parametrai. Trečios eilės charakteringosios lygties didysis ir mažasis diskriminantai atvaizduojami jungtinėje fazinėje plokštumoje. Duomenims buvo pasirinkti kriogeninės terapijos elektrokardiogramų parametrai. / Complex systems have new features that can not be predicted testing of the individual elements of the system. It was noted that the known systems of simple analytical methods are inadequate for new tasks, not respond to questions, therefore, to analyze complex systems need to develop new methods. Complex systems theory is a relatively new theory, and one of its major application areas is human body's functional status assessment, scientific hypothesis testing, and the new knowledge-based search tasks. Selected topics of work are certainly actual today's theory and practice. Were analyzed six electrocardiographic parameters in this work: durational RR-DQRS DJTp and amplitudical-AR-AT1-ATS2. Differences between parameters of the sequence of matrices drawn up and calculated invariantical parameters. Third-order characteristic equations, great and small discriminants are represented in the united phase plane. Electrocardiograms cryogenic therapy parameters have been chosen for data.

In New Zealand, a formal tree improvement and breeding programme for Pinus radiata (D.Don) commenced in 1952. A countrywide series of progeny trials was progressively established on over seventy sites, and is managed by the Radiata Pine Breeding Company (RPBC). Diameter at breast height data from the series were used to investigate genotype x environment interaction with a view to establishing the need for partitioning breeding and deployment efforts for P. radiata. Nearly 300,000 measurements made this study one of the largest for genotype x environment interaction ever done. Bivariate analyses were conducted between all pairs of sites to determine genetic correlations between sites. Genetic correlations were used to construct a proximity matrix by subtracting each correlation from unity. The process of constructing the matrix highlighted issues of low connectivity between sites; whereby meaningful correlations between sites were established with just 5 % of the pairs. However, nearly two-thirds of these genetic correlations were between -1.0 and 0.6, indicating the presence of strong genotype x environment interactions. A technique known as multiple regression on resemblance matrices was carried out by regressing a number of environmental correlation matrices on the diameter at breast height correlation matrix. Genotype x environment interactions were found to be driven by extreme maximum temperatures (t-statistic of 2.03 against critical t-value of 1.96 at 95 % confidence level). When tested on its own, altitude was significant with genetic correlations between sites at the 90 % confidence level (t-statistic of 1.92 against critical t-value of 1.645). In addition, a method from Graph Theory using proximity thresholds was utilised as a form of clustering. However, this study highlighted the existence of high internal cohesion within trial series, and high external isolation between trial series. That is, grouping of sites (in terms of diameter) was observed to be a reflection of the series of trials for which each site was established. This characteristic is particularly unhelpful for partitioning sites into regions of similar propensity to genotype x environment interaction, as the genotype x environment effect is effectively over-ridden by the genotype effect. Better cohesion between past, present and future trial series, and more accurate bioclimatic data should allow more useful groupings of sites to be extracted from the data. Given this, however, it is clear that there are a large number of interactive families contained in the RPBC dataset. It is concluded that partitioning of New Zealand’s P. radiata breeding programme cannot be ruled out as an advantageous option.

No description available.

Cette thèse présente une étude des propriétés de la lumière émise par des diffuseurs atomiques distribués aléatoirement dans l'espace euclidien, et interagissant avec le champ électromagnétique. Dans ce cadre, une théorie ab initio des lasers aléatoires est formulée en terme des propriétés statistiques de la 'matrice de Green'. Cette dernière appartient à la famille des matrices aléatoires euclidiennes (MAE) pour lesquelles nous développons une théorie analytique donnant notamment accès à la distribution de probabilité de leurs valeurs propres. Dans un premier temps, nous démontrons les équations quantiques microscopiques régissant la dynamique du champ électrique ainsi que celle des opérateurs atomiques, et explicitons comment la matrice de Green (dont les éléments sont égaux à la fonction de Green de l'équation de Helmholtz évaluée entre les différentes paires d'atomes constituant le milieu) émerge naturellement du formalisme quantique. Nous exprimons à la fois l'intensité et le spectre de la lumière en termes des propriétés de la matrice de Green, caractérisons les forces de Langevin quantiques, et montrons de quelle manière le seuil semi-classique d'un laser aléatoire est affecté par la prise en considération des fluctuations quantiques (chapitres 2 et 3). Une description mésoscopique et semi-classique de la lumière diffusée par un grand nombre d'atomes soumis à une pompe externe et distribués aléatoirement dans l'espace libre est présentée dans le quatrième chapitre. Après avoir établi une condition de seuil laser universelle, valide quelle que soit la configuration des atomes, nous démontrons une équation de transport obéie par l'intensité moyenne en présence de gain, discutons différentes approximations de cette dernière (équation de Bethe-Salpeter, équation de Boltzmann, équation de diffusion), établissons un 'mapping' avec les MAE, et analysons la condition de seuil laser déduite de l'équation de transport. Poussés par la volonté de caractériser analytiquement les propriétés statistiques de la matrice de Green, nous développons dans les chapitres 5 et 6 une théorie générale des MAE, hermitiennes et non hermitiennes, valide dans la limite de grande taille matricielle. Nous obtenons des équations couplées pour la résolvante et le corrélateur des vecteur propres d'une MAE arbitraire, puis testons la validité de nos résultats sur trois matrices jouant un rôle important dans l'étude de la propagation des ondes en milieux désordonnés: la matrice de Green dans l'espace tridimensionnel, sa partie imaginaire, et sa partie réelle. D'un point de vue physique, nous sommes capables de décrire analytiquement avec une bonne précision la distribution de probabilité des taux d'émission lumineux dus à un grand nombre d'atomes, ainsi que celle du déplacement lumineux collectif dû à l'interaction lumière-matière. Par ailleurs, nous proposons d'utiliser la distribution des valeurs propres de la matrice de Green non hermitienne comme une carte unique sur laquelle peuvent s'identifier différents régimes de désordre (balistique, diffusif, localisé, milieu effectif, superradiance). Finalement, nous combinons les équations microscopiques de l'interaction lumière-matière avec nos résultats relatifs aux MAE non-hermitiennes afin de caractériser dans le détail le comportement des lasers aléatoires. Le seuil laser ainsi que l'intensité au delà du seuil sont calculés analytiquement dans l'approximation semi-classique, et le spectre de la lumière sous le seuil est évalué en prenant en compte les effets quantiques. Notre théorie s'applique aussi bien à basse densité qu'à haute densité de diffuseurs atomiques.