The emerging importance of distributed computing systems raises the needs of gaining a better understanding of system performance. As a major indicator of system performance, analysing CPU host load helps evaluate system performance in many ways. Discovering similar patterns in CPU host load is very useful since many applications rely on the pattern mined from the CPU host load, such as pattern-based prediction, classification and relative rule mining of CPU host load.
Essentially, the problem of mining patterns in CPU host load is mining the time series data. Due to the complexity of the problem, many traditional mining techniques for time series data are not suitable anymore. Comparing to mining known patterns in time series, mining unknown patterns is a much more challenging task. In this thesis, we investigate the major difficulties of the problem and develop the techniques for mining unknown patterns by extending the traditional techniques of mining the known patterns.
In this thesis, we develop two different CPU host load discovery methods: the segment-based method and the reduction-based method to optimize the pattern discovery process. The segment-based method works by extracting segment features while the reduction-based method works by reducing the size of raw data. The segment-based pattern discovery method maps the CPU host load segments to a 5-dimension space, then applies the DBSCAN clustering method to discover similar segments. The reduction-based method reduces the dimensionality and numerosity of the CPU host load to reduce the search space. A cascade method is proposed to support accurate pattern mining while maintaining efficiency.
The investigations into the CPU host load data inspired us to further develop a pattern mining algorithm for general time series data. The method filters out the unlikely starting positions for reoccurring patterns at the early stage and then iteratively locates all best-matching patterns. The results obtained by our method do not contain any meaningless patterns, which has been a different problematic issue for a long time. Comparing to the state of art techniques, our method is more efficient and effective in most scenarios.
High-resolution large-eddy simulations (LES) are performed for an incompressible turbulent circular jet impinging upon a vibrating heated wall supplied with a constant heat flux. The present work serves to understand the flow dynamics and thermal characteristics of a turbulent jet under highly dynamic flow and geometric conditions. The baseline circular vibrating-wall jet impingement configuration undergoes a forced vibration in the wall-normal direction at the frequency, f = 100 Hz. The jet Reynolds number is = 23,000 and the nozzle-exit is at y/D = 2 where the wall vibrates between 0 and 0.5D with amplitude of vibration, A = 0.25D. The configuration is assembled through validation of sub-systems, in particular the method for generating the turbulent jet inflow and the baseline circular jet impingement configuration. Both time-mean and phase-averaged results are presented. The mean radial velocity increases upon positive displacement of the wall and decreases upon negative displacement but this correlation changes with increased radial distance from the stagnation point. Vortical structures are shown to play a major role in convective heat transfer even under the vibrating conditions of the impingement wall. Periodic shifts in the secondary Nusselt number peak are observed that depend upon the travelling eddy location and strength of large-eddy structures. Enhancement in heat transfer is seen in the stagnation region but this beneficial effect of vibration on heat transfer is confined to the impingement region, r/D < 1.5.
Thanks to a recent spate of sequencing projects, the Hemiptera are the first hemimetabolous insect order to achieve a critical mass of species with sequenced genomes, establishing the basis for comparative genomics of the bugs. However, as the most speciose hemimetabolous order, there is still a vast swathe of the hemipteran phylogeny that awaits genomic representation across subterranean, terrestrial, and aquatic habitats, and with lineage-specific and developmentally plastic cases of both wing polyphenisms and flightlessness. In this review, we highlight opportunities for taxonomic sampling beyond obvious pest species candidates, motivated by intriguing biological features of certain groups as well as the rich research tradition of ecological, physiological, developmental, and particularly cytogenetic investigation that spans the diversity of the Hemiptera.
We study the relaxation dynamics of fully clustered networks (maximal number of triangles) to an unclustered state under two different edge dynamics—the double-edge swap, corresponding to degree-preserving randomization of the configuration model, and single edge replacement, corresponding to full randomization of the Erdős-Rényi random graph. We derive expressions for the time evolution of the degree distribution, edge multiplicity distribution and clustering coefficient. We show that under both dynamics networks undergo a continuous phase transition in which a giant connected component is formed. We calculate the position of the phase transition analytically using the Erdős-Rényi phenomenology.
The magneto-mechanical memory (MMM) method, that is often referred to as the metal magnetic memory method, has been reported to be a non-destructive testing technique capable of quantifying stress concentrations and detecting defects in ferromagnetic materials. The underlying mechanism behind MMM has been explained in the literature, but the sensitivity to stress concentration has not been satisfactorily investigated. In this paper, both the normal and tangential components of the stress-induced MMM signal were measured by permanently installed magnetic sensor arrays on specimens made from three grades of L80 alloy steel and 20 other structural steels; tests were also carried out on a pipe made from the 4140-L80 steel. As expected, the stress history affects the MMM signal, but the experimental results show that significant irreversible change of magnetization always occurs only in the first cycle of loading regardless whether the deformation is purely elastic or partially plastic. If the peak stress level is increased at a given point during cycling, the immediately following next cycle acts as a new "first" cycle at that peak stress level and causes additional significant irreversible change of magnetization, but there is no evidence that plastic deformation might build up a cumulative magnetization. The MMM effect is very small in the steel samples tested, indicating that it will not be useful in field applications. In un-notched specimens the irreversible change in magnetization caused a proportional change in the measured external magnetic field on the order of only 5–10 A/m, while in the case of notched specimens the leakage field was on the order of 30–60 A/m.
This paper distinguishes two kinds of endogenous business cycle models: EBC1 models, which display dynamic indeterminacy, and EBC2 models, which display steady-state indeterminacy. Both strands of the literature have their origins in the sunspot literature that developed at the University of Pennsylvania in the 1980s. I argue that EBC1 models are part of the evolution of modern macroeconomics that has classical roots dating back to the 1920s. EBC2 models provide a microfoundation for one of the most important ideas to emerge from Keynes's (1936) General Theory of Employment, Interest and Money: that high involuntary unemployment can persist as part of the steady-state equilibrium of a market economy.
The Colorado potato beetle is one of the most challenging agricultural pests to manage. It has shown a spectacular ability to adapt to a variety of solanaceaeous plants and variable climates during its global invasion, and, notably, to rapidly evolve insecticide resistance. To examine evidence of rapid evolutionary change, and to understand the genetic basis of herbivory and insecticide resistance, we tested for structural and functional genomic changes relative to other arthropod species using genome sequencing, transcriptomics, and community annotation. Two factors that might facilitate rapid evolutionary change include transposable elements, which comprise at least 17% of the genome and are rapidly evolving compared to other Coleoptera, and high levels of nucleotide diversity in rapidly growing pest populations. Adaptations to plant feeding are evident in gene expansions and differential expression of digestive enzymes in gut tissues, as well as expansions of gustatory receptors for bitter tasting. Surprisingly, the suite of genes involved in insecticide resistance is similar to other beetles. Finally, duplications in the RNAi pathway might explain why Leptinotarsa decemlineata has high sensitivity to dsRNA. The L. decemlineata genome provides opportunities to investigate a broad range of phenotypes and to develop sustainable methods to control this widely successful pest.
Microbial communities closely associated with the rhizosphere can have strong positive and negative impacts on plant health and growth. We used a group-specific amplicon approach to investigate local scale drivers in the diversity and distribution of plasmodiophorids in rhizosphere/root and bulk soil samples from oilseed rape (OSR) and wheat agri-systems. Plasmodiophorids are plant- and stramenopile-associated protists including well known plant pathogens as well as symptomless endobiotic species. We detected 28 plasmodiophorid lineages (OTUs), many of them novel, and showed that plasmodiophorid communities were highly dissimilar and significantly divergent between wheat and OSR rhizospheres and between rhizosphere and bulk soil samples. Bulk soil communities were not significantly different between OSR and wheat systems. Wheat and OSR rhizospheres selected for different plasmodiophorid lineages. An OTU corresponding to Spongospora nasturtii was positively selected in the OSR rhizosphere, as were two genetically distinct OTUs. Two novel lineages related to Sorosphaerula veronicae were significantly associated with wheat rhizosphere samples, indicating unknown plant-protist relationships. We show that group-targeted eDNA approaches to microbial symbiont-host ecology reveal significant novel diversity and enable inference of differential activity and potential interactions between sequence types, as well as their presence.
This article reframes the extensive literature on the policing of protests in Paris in Mai '68 around (i) the concept, borrowed from Critical Security Studies, of the management of (in)security and (ii) Peter Manning's understanding of the dramaturgical function of policing. In the absence of direct archival evidence about how police felt during May, the article attempts a reconstruction – based on archival and secondary sources – of officers' experience of insecurity by highlighting the contrast between Mai and customary practice in managing demonstrations as 'co-productions' with the services d'ordre of trade unions and political parties. It is argued that the response of rank-and-file officers to Maurice Grimaud's strategy was widespread insubordination, contrary to the impression given in accounts by Grimaud himself. The role of le Service d'action civique (SAC) as clandestine policing auxiliaries is also discussed. The article concludes that the spread of police ways of knowing protestors into the wider population in the last week of May constituted a form of (in)security governance which worked by allowing ordinary people to feel sufficiently afraid to reaffirm their support of the regime and its frontline functionaries.
This thesis examines relations between charities and the state in Britain and Canada: it challenges a common view that government responsibility for welfare provision in this century has rendered charities relatively insignificant and isolated from the political process in both countries. By focusing specifically on medical research charities, evidence is presented to show that lobbying has become an increasingly important aspect of their activity, in spite of legal limitations restricting much of their involvement in the policy process. It is concluded that the law restricting charities from engaging in political activities has had limited success both because of its 'vagueness' and poor enforcement. The only countervailing force keeping medical research charities 'out of politics' to any significant degree has come from volunteers and the donating public, but, even they have had only a limited impact. The degree of political involvement by a charity is now contingent on the policy area in which it operates, the degree of 'hostility' of government policy towards the organisation and its objectives as well as the charity's financial resources.
In light of cut-backs in government expenditure to medical research in the 1980s, of the need to co-ordinate scientific investigations, and of pressures from some volunteers to represent the interests of disease sufferers, as well as a number of other factors, British and Canadian medical research charities have been drawn increasingly into the political process. This evidence suggests that charity-state relations have changed dramatically since the 19th century when charities not only resisted state encroachment into many areas of social welfare, but devoted much of their resources towards encouraging state withdrawal from areas where tax revenues were already being applied. Now charities frequently criticize government policies aimed at cutting-back state funding for programmes in policy areas where charities are operating and also propose new legislation to ensure minimum levels and quality of state-funded services.
Given this, the nature of charity-state relations has changed dramatically and has created difficulties for legislators who have had to reconcile the non-political qualities of philanthropy- including altruism, and community participation - with the reality that much charitable activity is devoted to participating in the policy process. In conclusion the blurring of the distinction between philanthropy and politics has meant that charities have begun to resemble more traditional forms of interest groups while at the same time maintaining their privileged 'tax exempt status'. This is a particularly interesting development given that many British and Canadian medical research charities have been co-opted by pharmaceutical companies to participate in a number of that industry's lobbying campaigns in return for corporate donations.
In this paper, we describe various definitions of geometrical finiteness for discrete hyperbolic groups in any dimension, and prove their equivalence. This generalises what has been worked out in two and three dimensions by Marden. Beardon, Maskit, Thurston and others. We also discuss the nature of convex fundamental domains for such groups. We begin the paper with a discussion of results related to the Margulls Lemma and Bieberbach Theorems.
The Magnetic Tomography Method (MTM), a passive Non-Destructive Testing (NDT) technique based on the magneto-mechanical effect, has been claimed to be able to detect defects at large (>1 m) stand-off distances. In this study, the MTM signal was studied experimentally on a 4140-L80 pipe sample, in which a flat bottom defect was electrochemically generated. The Residual Magnetic Leakage Field (RMLF) signal was recorded using an annular array of AMR sensors. The experimental results show perturbations due to the defect (about 12 dB above noise level) only when the AMR sensors were positioned at a very low stand-off. The presence of ferromagnetic objects near the sensors could cause perturbations many times larger than that from a defect (about 18 dB above the noise level). A Finite Element (FE) model validated the experimental results. The model showed that there is a significant risk of false indications due to foreign ferromagnetic objects when measuring at a large distance from the pipe.