In shared-disk database systems, disk access has to be scheduled properly to avoid unnecessary contention between processors. The first part of this report studies the allocation of intermediate results of join queries (buckets) on disk and derives heuristics to determine the number of processing nodes and disks to employ. Using an analytical model, we show that declustering should be applied even for single buckets to ensure optimal performance. In the second part, we consider the order of reading the buckets and demonstrate the necessity of highly dynamic load balancing to prevent excessive disk contention, especially under skew conditions.

In the course of evolution, genomes diverge from their ancestors either via global mutations and by rearrangement of their chromosomal segments, or through local mutations within their genes. In this thesis (Chapters: 2, 3 and 4) we analyze the evolution of genomes based on different rearrangement operations including: in Chapter 2 both restricted and unrestricted double-cut-and-join (DCJ) operations, in Chapter 3 both internal and general reversal and translocation (IRT and HP, respectively) operations, and in Chapter 4 translocation, weighted reversal (WR) and maximum length reversal (MLR) operations. Based on the rearrangement operation chosen we can model the evolution of genomes as a discrete or continuous-time Markov chain process on the space of signed genomes. For each model of evolution, we study the stochastic process by investigating the time up to which the difference between the number of operations along the evolutionary trajectory and the edit distance of the genome from its ancestor is negligible, as soon as these two values starts diverging drastically from one another we say the process escapes from parsimony. One of the major parameters in the known edit distance formulas between any two genomes (such as reversal, DCJ, IRT, HP and translocation) is the number of cycles in their breakpoint graph. For DCJ, IRT and HP models by adopting the method elaborated by Berestycki and Durret, we estimate the number of cycles in the breakpoint graph of the genome at time t and its ancestor by the number of tree components of the random graph constructed from the model of evolution at time t, which is an Erdös-Rényi. We also proved that for each of the DCJ, IRT and HP models of evolution, the process on a genome of size n is bound to its parsimonious estimate up to t ≈ n/2 steps. Since the random graph constructed from the models of evolution for the translocation, WR and MLR processes are not Erdös-Rényi, the proofs of their parsimony- bound require more advanced mathematical tools, however our simulation shows for the translocation, two types of WR, and MLR (except for reversals with very short maximum length) models, the escape from parsimony do not occur before n/2 steps, where n is the number of genes in the genome. A basic result in this field is due to Berestycki and Durrett, from 2006, who found that a random transposition (pairwise exchange of the elements in the corresponding permutation of the genome) evolves along its parsimonious path of evolution up to n/2 steps, where n is the number of the genes. Although, this transposition model is applicable solely for evolution of a unichromosomal ancestor which remains unichromosomal at each step t of the process; however for the DCJ, IRT, HP and translocation models the genomes are multichromosomal which increases the difficulty of the problem at hand. The models studied in Chapters 2 - 4 are all based on signed permutation representations of genomes, where each "gene" occurs exactly once, with either positive or negative polarity. The same genes occur in all the genomes being considered. There is no distinction between the same gene in two different genomes. In Chapter 5 we generalize our representation to genes that may have several copies of a gene, which differ only by a few point mutations. This leads to problems of identifying copies in two genomes that are primary orthologs, under the assumptions of differentials in point mutation rate. We provide algorithms, software and test examples.

The Chow/Van der Waerden approach to algebraic cycles via resultants is elaborated and used to give a purely algebraic proof for the algebraicity of the complex suspension over arbitrary fields. The algebraicity of the join pairing on Chow varieties then follows over the complex numbers. The approach implies a more algebraic proof of Lawson´s complex suspension theorem in characteristic 0. The continuity of the action of the linear isometries operad on the group completion of the stable Chow variety is a consequence. Further Hoyt´s proof of the independence of the algebraic-continuous homeomorphism type of Chow varieties on embeddings is rectified and worked out over arbitrary fields.

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This thesis aims to understand how Sweden managed to renounce its long-held military non-alignment policy and identity to join the military alliance NATO in the aftermath of Russia`s full-scale invasion of Ukraine. In order to find out how Sweden achieved this policy shift the thesis builds on social constructivism and studies on ontological security that focuses on the security of identities and adopts the case study method. To answer the research question, the ontological security maximization framework -which presents two complementary strategies that agents must achieve to be able to undertake change-making action- is applied to the selected speeches of Magdalena Andersson, Peter Hultqvist, and Ann Linde, the three leading Swedish politicians that were involved in the decision-making process of the policy change. Regarding the first strategy, the strategy of being, eight distinct identity-signifiers that enhance the Swedish self-esteem and ensure biographical continuity have been identified in the Swedish narrative. When it comes to the second strategy, the strategy of doing, the action “joining NATO” is evaluated positively in three different ways and this was done in a way that consolidates the strategy of being. Furthermore, by addressing the obstacles optimistically- most notably the issue with Türkiye- the three politicians have successfully maximised the Swedish ontological security, thus enabling the initiation of this fundamental policy change.

It is known that a Cayley digraph of an abelian group A is isomorphic to a nontrivial wreath product if and only if there is a proper nontrivial subgroup B of A such that the connection set without B is a union of cosets of B in A. We generalize this result to Cayley digraphs of nonabelian groups G by showing that such a digraph is isomorphic to a nontrivial wreath product if and only if there is a proper nontrivial subgroup H of G such that S without H is a union of double cosets of H in G. This result is proven in the more general situation of a double coset digraph (also known as a Sabidussi coset digraph.) We then give applications of this result which include obtaining a graph theoretic definition of double coset digraphs, and determining the relationship between a double coset digraph and its corresponding Cayley digraph. We further expand the result obtained for double coset digraphs to a collection of bipartite graphs called bi-coset graphs and the bipartite equivalent to Cayley graphs called Haar graphs. Instead of considering when this collection of graphs is a wreath product, we consider the more general graph product known as an X-join by showing that a connected bi-coset graph of a group G with respect to some subgroups L and R of G is isomorphic to an X-join of a collection of empty graphs if and only if the connection set is a union of double cosets of some subgroups N containing L and M containing R in G. The automorphism group of such -joins is also found. We also prove that disconnected bi-coset graphs are always isomorphic to a wreath product of an empty graph with a bi-coset graph.

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Yes / Daily physical activity is vital for the health and development of children. However, many children are inactive. Previous attempts to achieve sustained increases in daily physical activity in children have been ineffective. Join Us: Move Play (JU:MP) is a whole-system, complex, community-based intervention aiming to increase the physical activity levels of children aged 7 to 11 years who live in areas of Bradford, England, which are multicultural and have high levels of deprivation. The purpose of this quasiexperimental controlled trial is to assess whether the JU:MP program increases primary school children's physical activity. The study has a 2-arm, quasiexperimental, nonblinded, nonequivalent group design and will be conducted with primary school children aged 5 to 11 years at 3 timepoints, including baseline (before intervention), 24 months (during intervention), and 36 months (after intervention). Children attending primary schools within the intervention area will be invited to participate. Children attending similar schools within similar neighborhoods based on school and community census demographics (deprivation, free school meals, and ethnicity) outside of the JU:MP geographical area will be invited to participate in the control condition. At each timepoint, consenting participants will wear an accelerometer for 7 consecutive days (24 hours a day) to measure the primary outcome (average daily moderate-to-vigorous physical activity). Multivariable mixed effects linear regression will be applied to estimate differences in the primary outcome between the 2 arms at 24 months and 36 months on an intention-to-treat basis. The secondary outcome analysis will explore changes in socioemotional well-being (teacher reported), quality of life (parental/carer reported), and other contextual factors (parents/carer reported), as well as segments of the day activity, sleep, sedentary screen time, frequency of places to be active, parent practices (nondirective support and autonomy support), social cohesion, and neighborhood walking/exercise environment. Recruitment occurred from July 2021 to March 2022, and baseline data were collected from September 2021 to March 2022. As of March 2022 (end of baseline data collection), a total of 1454 children from 37 schools (17 intervention schools and 20 control schools) have been recruited. The first follow-up data collection will occur from September 2023 to March 2024, and the second and final follow-up data collection will occur from September 2024 to March 2025. Data analysis has not begun, and the final results will be published in December 2025. This article describes the protocol for a quasiexperimental controlled trial examining a novel whole-system intervention. ISRCTN ISRCTN14332797; https://www.isrctn.com/ISRCTN14332797. DERR1-10.2196/43619.

Undoubtedly, state-of-the-art unit selection-based concatenative speech systems produce very high quality synthetic speech. this is due to a large speech database containing many instances of each speech unit, with a varied and natural distribution of prosodic and spectral characteristics. the join cost, which measures how well two units can be joined together is one of the main criteria for selecting appropriate units from this large speech database. The ideal join cost is one that measures percieved discontinuity based on easily measurable spectral properties of the units being joined, inorder to ensure smooth and natural sounding synthetic speech. During first part of my research, I have investigated various spectrally based distance measures for use in computation of the join cost by designing a perceptual listening experiment. A variation to the usual perceptual test paradigm is proposed in this thesis by deliberately including a wide range of qualities of join in polysyllabic words. The test stimuli are obtained using a state-of-the-art unit-selection text-to-speech system: rVoice from Rhetorical Systems Ltd. Three spectral features Mel-frequency cepstral coefficients (MFCC), line spectral frequencies (LSF) and multiple centroid analysis (MCA) parameters and various statistical distances - Euclidean, Kullback-Leibler, Mahalanobis - are used to obtain distance measures. Based on the correlations between perceptual scores and these spectral distances. I proposed new spectral distance measures, which have good correlation with human perception to concatenation discontinuities. The second part of my research concentrates on combining join cost computation and the smoothing operation, which is required to disguise joins, by learning an underlying representation from the acoustic signal. In order to accomplish this task, I have chosen linear dynamic models (LDM), sometimes known as Kalman filters. Three different initialisation schemes are used prior to Expectation-Maximisation (KM) in LDM training. Once the models are trained, the join cost is computed based on the error between model predictions and actual observations. Analytical measures are derived based on the shape of this error plot. These measures and initialisation schemes are compared by computing correlations using the perceptual data. The LDMs are also able to smooth the observations which are then used to synthesise speech. To evaluate the LDM smoothing operation, another listening test is performed where it is compared with the standard methods (simple linear interpolation). I have compared the best three join cost functions, chosen from the first and second parts of my research, subjectively using a listening test in the third part of my research. in this test, I also evaluated different smoothing methods: no smoothing, linear smoothing and smoothing achieved using LDMs.