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Markus M.,University of Illinois at Urbana - Champaign | Knapp H.V.,University of Illinois at Urbana - Champaign | Flegel A.,University of Illinois at Urbana - Champaign | McConkey S.,University of Illinois at Urbana - Champaign | Thomas W.O.,Baker Corporation
Journal of Hydrologic Engineering | Year: 2013

Decreasing annual maximum flood peaks on the rivers and streams in the Wisconsin driftless area have been reported in recent studies. Various explanations have been offered, generally suggesting different episodes or change points separating the early periods of higher peak flows from the more recent lower peak flows. The present research used two statistical tests to detect a change point in annual flood peaks at Freeport on the Pecatonica River for the period 1914-2008. Both tests indicated that the most significant change occurred in 1954. Next, to find an explanation for the decreasing peaks, this research carried out a seasonal analysis of flood timing. The decrease in winter flood peaks was partly explained by the decrease in snow depth and the increase in winter temperature, providing less favorable conditions for winter flooding. In turn, the decrease in winter peak flows made once smaller summer peak flows more dominant in recent years, causing the shift in flood timing. Similar analysis showed a significant degree of resemblance between the Pecatonica River and several streams in its vicinity. © 2013 American Society of Civil Engineers.

Barton M.,Technion - Israel Institute of Technology | Hanniel I.,Technion - Israel Institute of Technology | Hanniel I.,Baker Corporation | Elber G.,Technion - Israel Institute of Technology | Kim M.-S.,Seoul National University
Computer Aided Geometric Design | Year: 2010

We present an exact algorithm for computing the precise Hausdorff distance between two general polyhedra represented as triangular meshes. The locus of candidate points, events where the Hausdorff distance may occur, is fully classified. These events include simple cases where foot points of vertices are examined as well as more complicated cases where extreme distance evaluation is needed on the intersection curve of one mesh with the medial axis of the other mesh. No explicit reconstruction of the medial axis is conducted and only bisectors of pairs of primitives (i.e. vertex, edge, or face) are analytically constructed and intersected with the other mesh, yielding a set of conic segments. For each conic segment, the distance functions to all primitives are constructed and the maximum value of their low envelope function may correspond to a candidate point for the Hausdorff distance. The algorithm is fully implemented and several experimental results are also presented. © 2010 Elsevier B.V.

Wojtowicz R.L.,Baker Corporation | Wojtowicz R.L.,Shepherd University
Innovations in Systems and Software Engineering | Year: 2016

In this paper, we give an overview of sketch theory as a knowledge management framework and discuss its strengths relative to logic, the semantic web and relational algebra. Sketch theory, for example, supports modularity among meta-data, instance data and uncertainty. It also provides a notion of constraint-preserving map. We explore Q-trees as a technique for inference with sketches and compare it to logical deduction. Ideas can be formulated in distinct ways even within a fixed formalism. We illustrate solution of this alignment problem using sketches and the notion of Morita equivalence of logical theories. Sketch theory provides rich notions of contextual view with which we compute illustrative examples. Finally, we outline a program for advancing sketch theory as a complement to other knowledge management technologies and discuss transformations between sketches and other models. © 2015, Springer-Verlag London.

Baker B.,Baker Corporation
IBM Data Management Magazine | Year: 2010

Bonnie Baker explores the use of SQL predicates-how they may improve performance, and how DB2 works with predicate statements in parsing.

Baker B.,Baker Corporation
IBM Data Management Magazine | Year: 2010

Are you following best practices in your programming methods? Bonnie Baker offers up more examples of bad SQL habits that need to be broken to help eliminate or reduce conversations with DB2 for z/OS.

Villotti L.,Baker Corporation | Brethauer W.K.,Highway Performance Monitoring System
Public Roads | Year: 2013

Communities ins Southwestern Pennsylvania used the scenario planning process to develop a vision scenario that prioritizes investments in revitalization and redevelopment of existing infrastructure. In the early years of developing growth projections, they were almost purely developed using straight-lined trending. That process involves simply carrying the most recent past trends from the current situation to some point in future, using an annual growth factor. Although accurate in the near term, the overall usefulness of this approach over time was dependent on duration and stagnation. The farther from the origination date, the less accurate the projections became, because the important input variables changed, instead of staying stagnant, and their ability to maintain accuracy degraded. A scenario is essentially a story about the future that helps people understand the forces of change and the collective choices they have.

Barton M.,Technion - Israel Institute of Technology | Elber G.,Technion - Israel Institute of Technology | Hanniel I.,Technion - Israel Institute of Technology | Hanniel I.,Baker Corporation
CAD Computer Aided Design | Year: 2011

We present an algorithm which robustly computes the intersection curve(s) of an underconstrained piecewise polynomial system consisting of n equations with n+1 unknowns. The solution of such a system is typically a curve in Rn+1. This work extends the single solution test of Hanniel and Elber (2007) [6] for a set of algebraic constraints from zero-dimensional solutions to univariate solutions, in Rn+1. Our method exploits two tests: a no-loop test (NLT) and a single-component test (SCT) that together isolate and separate domains D where the solution curve consists of just one single component. For such domains, a numerical curve tracing is applied. If one of those tests fails, D is subdivided. Finally, the single components are merged together and, consequently, the topological configuration of the resulting curve is guaranteed. Several possible applications of the solver, namely solving the surfacesurface intersection problem, computing 3D trisector curves, flecnodal curves or kinematic simulations in 3D are also discussed. © 2011 Elsevier Ltd. All rights reserved.

Kupai M.M.,University of Alberta | Yang F.,University of Alberta | Harbottle D.,University of Alberta | Moran K.,Baker Corporation | And 2 more authors.
Canadian Journal of Chemical Engineering | Year: 2013

In oil sands froth treatment, an undesirable intermediate layer, often accumulates during the separation of water-oil emulsions. The layer referred to as rag layer is a complex mixture of water, oil, solids and interfacially active components. The presence of a rag layer has a detrimental impact on the separation of water and fine solids from diluted bitumen. The current study focuses on characterisation of solids from a rag layer forming stream of a naphthenic froth treatment plant in an attempt to understand the mechanism of rag layer formation. Through detailed characterisation of rag-forming and non-rag-forming solids, the mineralogy of solids and their contamination were shown to be critical to rag layer formation. The iron-based minerals such as siderite and pyrite were found to be enriched within the rag layer. Analysis of surface organic complexes confirms a high level of organic matter associated with these solids through the binding of carboxylic acid group with iron on solids, resulting in a surface hydrophobicity susceptible for rag layer formation. © 2013 Canadian Society for Chemical Engineering.

Gao S.,University of Alberta | Moran K.,Baker Corporation | Xu Z.,University of Alberta | Masliyah J.,University of Alberta
Journal of Physical Chemistry B | Year: 2010

The need for alkaline conditions in oil sands processing is, in part, to produce natural surfactants from bitumen. Previous studies have shown that the produced surfactants are primarily carboxylic salts of naphthenic acids with the possibility of sulfonic salts as well. The role of these natural surfactants, particularly those in the naphthenate class, is to provide a physicochemical basis for several subprocesses in bitumen extraction. In this study, it was found that the content of indigenous naphthenic acids in bitumen can destabilize, to some extent, the water-in-oil emulsion by lowering the interfacial tension, reducing the rigidity and promoting the coalescence of water droplets. © 2010 American Chemical Society.

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