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Edmonton, Canada

For other similarly named institutions, see Concordia University Concordia University College of Alberta, is an independent publicly funded university in Edmonton, Alberta, Canada. Accredited under the Alberta Post-secondary Learning Act. Concordia is primarily funded by the Government of Alberta, tuition, and private donations. Wikipedia.

Schnitzler E.G.,Concordia University College of Alberta | Schnitzler E.G.,University of Alberta | McDonald K.M.,Concordia University College of Alberta
Atmospheric Environment | Year: 2012

Many models of secondary organic aerosol (SOA) formation, adhering to gas-particle equilibrium partitioning theory, require known vapour pressures for low volatility products of volatile organic compound (VOC) oxidation. Since the majority of such products have yet to be isolated and analysed, few experimental determinations of pertinent vapour pressures have been achieved, and models are forced to rely on vapour pressure estimates, such as those available through the common, computer-based SPARC and MPBPWIN property calculators. Thus, the accuracy of the respective estimation methods must be measured and evaluated, in order to determine the consequences in the resulting models. However, published evaluations, and most models themselves, typically focus on moderate to high ambient temperatures, which may not be applicable year-round in colder regions, where the rate of VOC oxidation slows, while the vapour pressures of the products decrease, indicating an increased tendency to condense into the aerosol phase. In this paper, the accuracy of the SPARC and MPBPWIN methods is evaluated over a broad temperature range, from 248.15 to 298.15. K, in five degree intervals using a test set of 45 compounds. The results are reported in terms of mean average error (MAE) and mean bias error (MBE), and given for alcohol, carboxylic acid, aldehyde, and ketone compound classes at each temperature. Specific trends in MAE and MBE with regard to compound class and changing temperature are discussed. More generally, the evaluation indicates that SPARC, with MAE decreasing from 0.288 at 248.15. K to 0.165 at 298.15. K and MBE increasing from -0.180 at 248.15. K to a peak of -0.081 at 293.15. K, is more accurate at low to moderate temperatures than MPBPWIN, with MAE decreasing from 0.436 at 248.15. K to 0.272 at 298.15. K and MBE increasing from -0.328 at 248.15. K to -0.213 at 298.15. K. Decreasing accuracy at lower temperatures emphasizes a need for focused experimental and model efforts in this temperature range. © 2012 Elsevier Ltd. Source

Young A.E.,Liberty Mutual Research Institute for Safety | Wasiak R.,United Biosource Corporation | Phillips L.,Concordia University College of Alberta | Gross D.P.,University of Alberta
Pain | Year: 2011

Although various measures of low back pain (LBP) recurrence have been proposed, none have been tested to determine if they are consistent with what those with LBP perceive a "recurrence" to be. To further the understanding of LBP recurrence and how to measure it, we examined how individuals with a history of LBP describe their back pain experiences. A qualitative approach was chosen and six mixed-gender focus groups were conducted. Discussions were facilitated by two researchers and structured around predetermined questions. All four authors were involved in the data analysis and thematic congruence was achieved through an iterative process of coding and discussion. Participants included 31 individuals (14 female, 17 male), with ages ranging from early 20s to mid 70s. When asked about LBP recurrence, participants had difficulty understanding the concept. There was a sense that, although the pain may disappear, the condition was always there. Three states were defined: "normal," "flared-up," and "attack." "Normal" could include experiencing pain, but generally represented a tolerable state. "Flared-up" was associated with increased pain, the use of strategies to overcome difficulties, and modified participation. "Attack" state was described as severely disabled: "I just have to lay there." Participants described their experiences in a way that is consistent with the idea that LBP is a fluctuating and disabling health condition. Results cast doubt on the validity of currently available measures of LBP recurrence. Focusing on recurrence of pain without consideration of broader contextual factors will result in an incomplete understanding of the meaning of the pain experience. © 2010 International Association for the Study of Pain. Published by Elsevier B.V. All rights reserved. Source

Law C.C.H.,Concordia University College of Alberta | Chen C.C.,Appalachian State University | Wu B.J.P.,Tamkang University
Computers in Industry | Year: 2010

Companies adopting enterprise resource planning (ERP) systems have often focused primarily on implementation-related factors while neglecting those of post-implementation. As a result, the usefulness and operation of the ERP systems, once installed, are compromised. This research adopted a case study approach to demonstrate that ERP adoption efforts that fail to pay attention to post-implementation requirements (especially those relevant to maintenance and support (M&S)) from an early stage in the project lifecycle will face dire consequences. It points out that poor planning and management of M&S services can imperil the normal operations of an ERP system and the daily activities of a business. With the life span of ERP systems getting shorter, sound M&S practices can extend their life and create a stable system platform to support efficient and effective business operations. M&S issues deserve to be considered as integral elements among the critical success factors (CSF) of ERP adoption projects. In other words, ERP success requires a full lifecycle perspective to be taken by adopting companies. With lessons having been learned from the mistakes in the first project, the company in this case study revamped its ERP implementation second time out, with due consideration being given to M&S strategies and practices from project initiation onward in order to realize a stable, usable, and maintainable system. The case study explores and identifies the critical success factors (CSF) of ERP adoption, and shows that M&S must be included as a key element from the outset and throughout the system lifecycle. Our findings capture a great deal of experience for any ERP adopting companies to follow in order to avoid learning costly lessons both in implementation and subsequent M&S throughout the lifespan of the system. A set of propositions is also presented for academic researcher to consider in future ERP research endeavors. © 2009 Elsevier B.V. All rights reserved. Source

Cui B.,Beijing Normal University | He Q.,Beijing Normal University | Zhang K.,University of Calgary | Chen X.,Concordia University College of Alberta
Oecologia | Year: 2011

Vegetation zonation patterns in coastal marshes are hypothesized to be the result of both physical stress and competitive interactions. How these patterns may be driven by these factors at different life history stages remains poorly understood. We investigated the relative importance of species tolerance (response to physical stress) and competitive ability in determining the distributions of two dominant marsh species across a salt-fresh marsh interface in the Yellow River Estuary, China. There is a steep gradient in salinity across this interface and Suaeda salsa, an annual, dominates the saline side of the interface, while Phragmites australis, a perennial species, dominates the freshwater side. Using a series of field transplants, we examined the roles of physical stress and competition in mediating this zonation at different life history stages. Suaeda salsa performed well in its home zone, but seedling emergence, seedling survival, adult survival and adult growth were significantly suppressed by competition in the freshwater P. australis zone. Emergence, survival and growth of P. australis were inhibited in the saline S. salsa zone, regardless of neighbor treatments, but it performed well in its home zone. The magnitude of the competitive effect on the performance of S. salsa differed among the life history stages. Competition from P. australis had a much stronger effect on S. salsa seedling emergence and adult growth than on seedling survival and adult survival. Our results reveal that both physical stress and competition contributed to the observed zonation patterns in this marsh system. However, for S. salsa, the effect of competition varied with life-history stage. Insight into these ecological processes is critical to understanding how the zonation pattern in the marsh system is formed and maintained. © 2011 Springer-Verlag. Source

Butakov S.,Concordia University College of Alberta
CEUR Workshop Proceedings | Year: 2013

Data leak prevention systems become a must-have component of enterprise information security. To minimize the communication delay, these systems require fast mechanisms for massive document comparison. Bloom filters have been proven to be a fast tool for membership checkup with some allowed level of false positive errors. Taking into account specific needs of fast text comparison this paper proposes modifications to the Matrix Bloom filters. Approach proposed in this paper allows to improve density in Matrix Bloom filters with the help of special index to track documents uploaded into the system. Density is improved by combining a few documents in one line of the matrix to reduce the filter size and to address the problem of document removal. The experiment provided in the paper outlines advantages and applicability of the proposed approach. Copyright © 2013 for the individual papers by the papers' authors. Source

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