Truss decomposition is an essential problem in graph mining, which focuses on discovering dense subgraphs of a graph. Detecting trusses in deterministic graphs is extensively studied in the literature. As most of the real-world graphs, such as social, biological, and communication networks, are associated with uncertainty, it is of great importance to study truss decomposition in a probabilistic context. However, the problem has received much less attention in a probabilistic framework. Furthermore, due to computational challenges of truss decomposition in probabilistic graphs, state-of- the-art approaches are not scalable to large graphs. Formally, given a user-defined threshold k (for truss denseness), we are interested in finding all the maximal subgraphs, which are a k-truss with high probability. In this thesis, we introduce a novel approach based on an asynchronous h-index updating process, which offers significant improvement over the state-of-the-art. Our extensive experimental results confirm the scalability and efficiency of our approach. / Graduate

The present research examined the effects that the variables of burial depth and presence of a plastic covering material had on the decomposition rate of fetal remains. The experimental sample consisted of fetal pigs (Sus scrofa) as a substitute for fetal human remains. The general size and bone composition of fetal pigs are comparable to those of fetal humans. The decomposition of the fetal pigs remains was observed in four independent variable groups: 20 cm unwrapped, 20 cm wrapped, 60 cm unwrapped, and 60 cm wrapped, per time period. The author hypothesized that the rate of decay would be slower for wrapped remains or for remains at a greater burial depth. The results of the two different burial depths and of the wrapped versus unwrapped groups was analyzed to determine the effects of those variables on the rate of decomposition. Analysis of these remains consisted of quantitative data, including pre-burial and post-burial mass comparison as well as the Total Body Score. It was found that wrapping was a significant influencer of mass loss with a p value of 0.0298 but not for the Total Body Score with a p value of 0.17565, while burial depth did not have a significant effect on either mass loss nor Total Body Score with a p value of 0.1956 and 0.08969, respectively.

Ph.D, Faculty of Science, University of the Witwatersrand, 2011 / Investigations into methane conversion (both catalytic and non-catalytic) and characterization of the carbon produced for use in high efficiency DCFCs were performed. Under non-catalytic processes, a high methane conversion (> 80%) was achieved at 1200 oC at flow rates of between 10-60 ml/min. Analysis of the carbon using Raman spectroscopy showed that the carbon was highly disordered and the degree of disorder increased with increase in methane flow rate (from aD/aG = 1.54 at 10 ml to aD/aG = 2.24 at 60 ml/min). Further analysis of the carbon using thermogravimetric analysis (TGA) demonstrated that the carbon produced at higher flow rates e.g. 100 ml/min were easily oxidized (746 oC) compared with those produced at lower flow rates (10 ml/min, 846 oC). Therefore, a high temperature coupled with high flow rates (60-100 ml/min) produced carbon with desired qualities (high disorder, low crystallinity and more thermally reactive) for DCFC uses. In the catalytic decomposition of methane, Ni supported on TiO2 and a 1:1 mixture of TiO2/Al2O3 gave high and stable methane conversions of about 60% at only 600 oC compared to 1200 oC required for the non-catalytic conversion. These catalysts were found to be the best catalyst systems of the tested catalysts. Considering the thermal oxidation and crystallinity data which are some of the properties of the carbon required for direct carbon fuel cells (DCFCs), the carbon produced can potentially be used in DCFC systems.

In this dissertation, we study an important problem of security in wireless networks. We study different attacks and defense strategies in general and more specifically jamming attacks. We begin the dissertation by providing a tutorial introducing the operations research community to the various types of attacks and defense strategies in wireless networks. In this tutorial, we give examples of mathematical programming models to model jamming attacks and defense against jamming attacks in wireless networks. Later we provide a comprehensive taxonomic classification of the various types of jamming attacks and defense against jamming attacks. The classification scheme will provide a one stop location for future researchers on various jamming attack and defense strategies studied in literature. This classification scheme also highlights the areas of research in jamming attack and defense against jamming attacks which have received less attention and could be a good area of focus for future research. In the next chapter, we provide a bi-level mathematical programming model to study jamming attack and defense strategy. We solve this using a game-theoretic approach and also study the impact of power level, location of jamming device, and the number of transmission channels available to transmit data on the attack and defense against jamming attacks. We show that by increasing the number of jamming devices the throughput of the network drops by at least 7%. Finally we study a special type of jamming attack, flow-jamming attack. We provide a mathematical programming model to solve the location of jamming devices to increase the impact of flow-jamming attacks on wireless networks. We provide a Benders decomposition algorithm along with some acceleration techniques to solve large problem instances in reasonable amount of time. We draw some insights about the impact of power, location and size of the network on the impact of flow-jamming attacks in wireless networks.

In the absence of canopy-opening disturbances, upland oak forests in the eastern United States are shifting to shade-tolerant, fire-sensitive tree species (i.e. mesophytes) via a hypothesized positive feedback loop of less flammable, self-promoting conditions, termed mesophication. To evaluate species-specific impacts on mesophication, I quantified canopy, bark, and leaf litter traits of five hypothesized mesophytes [red maple (Acer rubrum), sugar maple (A. saccharum), American beech (Fagus grandifolia), hickory (Carya spp.), and tulip poplar (Liriodendron tulipifera)] and four upland oaks [black oak (Quercus velutina), chestnut oak (Q. montana), scarlet oak (Q. coccinea), and white oak (Q. alba)] in central Kentucky. Red maple, sugar maple, and American beech had increased canopy depth with stem size, smoother bark, and small, thin leaves when compared to oaks. My findings suggest that some mesophytes, such as red maple, sugar maple, and American beech, may decrease future forest flammability by reducing understory light and increasing fuel moisture.

No description available.

Multiway data are becoming more and more common. While there are many approaches to extending principal component analysis (PCA) from usual data matrices to multiway arrays, their conceptual differences from the usual PCA, and the methodological implications of such differences remain largely unknown. This thesis aims to specifically address these questions. In particular, we clarify the subtle difference between PCA and singular value decomposition (SVD) for multiway data, and show that multiway principal components (PCs) can be estimated reliably in absence of the eigengaps required by the usual PCA, and in general much more efficiently than the usual PCs. Furthermore, the sample multiway PCs are asymptotically independent and hence allow for separate and more accurate inferences about the population PCs. The practical merits of multiway PCA are further demonstrated through numerical, both simulated and real data, examples.

Building structure of wine-growing is situated in the countryside not far from the village Strachotin in South Moravia. Concerned area slopes wildly down to the level of the water reservoir. To the building of production concures parts of presentation, degustation, and distribution of wine. This area includes also leisure centre with possibility of accomodation , visit of wellness, seminary rooms, restaurant and coffee. Buildings for accomodation and some other are designed as energetically selfsufficient wooden structures using energy from renewable natural resources.

<p> This work was initiated with a view to elucidating the hitherto little-studied thermolysis of esters of oxalic acid. A number of symmetrical diesters were synthesized and several were investigated thoroughly by use of product studies, kinetic methods and kinetic isotope-effect measurements. Both preparative and pyrolytic procedures and results are recorded. The literature regarding previous studies of the effect of heat on oxalate esters is surveyed, and a review of the principles and uses of the investigative methods employed is presented. The results are discussed in the light of more recent work and both general and specific mechanisms for oxalate thermolysis are suggested.</p> / Thesis / Doctor of Philosophy (PhD)

<p> The reaction of lead tetra-acetate with ketone carbohydrazones and 4-substituted semicarbazones gave a series of 2-(substituted imino)-△^3-1,3,4-oxadiazolines. Spectroscopic and chemical evidence is presented to establish the proposed structure, and the scope of the reaction is described. The thermolysis of the 5,5-diaryl-2-phenylimino-△^3-1,3,4-oxadiazolines was studied in chlorobenzene solution. The results of kinetic experiments (gas evolution and infra-red) are reported, and the mechanism of the decomposition is discussed. A survey of the literature pertaining to related lead tetra-acetate oxidations, and to decomposition of cyclic azo compounds is presented.</p> / Thesis / Doctor of Philosophy (PhD)