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BCIT Citations Collection

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Structured documents
Proceedings of 2012 European Intelligence and Security Informatics Conference (EISIC) in Odense, Denmark 22-24 Aug. 2012. Much of the information exchanged between agents over a network is encapsulated in XML documents. An XML document has a tree structure, and the meaning of the document can be understood in terms of a set of label-value pairs. The content of a document is often secured through digital signatures applied to different sections, while the document is passed between several agents. In this paper, we illustrate that this process is insecure in the sense that a malicious agent can deceive an honest agent to hold beliefs that are untrue. We provide a formal framework for analyzing the security of structured documents, based on the implicit epistemic impact that a signed document will have on a recipient. This kind of analysis can provide significant insight into deception and fraud detection., Conference paper, Published.
Student emotions with an edu-game
Proceedings of 2013 Humaine Association Conference on Affective Computing and Intelligent Interaction, Geneva, Switzerland, 2-5 Sept. 2013. We present the results of a study that explored the emotions experienced by students during interaction with an educational game for math (Heroes of Math Island). Starting from emotion frameworks in affective computing and education, we considered a larger set of emotions than in related research. For emotion labeling, we employed a standard method that relies on trained judges to report emotions over 20-second intervals. However, we asked judges to report all observed emotions in each interval, as opposed to only choosing one, as is standard practice. This variation allows us to discuss the appropriateness of this interval for emotion labeling. We present a detailed analysis of inter-coder reliability, both aggregated and over individual students, that considers not only the matching by judges over emotion type, but also the number of emotions detected., Conference paper, Published., Peer reviewed
Suppression of positional errors in biological development
Cells in developing embryos behave according to their positions in the organism, and therefore seem to be receiving `positional information'. A widespread view of the mechanism for this is that each cell responds locally to the concentration level of some extracellular chemical which is distributed in a spatial gradient. For molecules conveying and receiving the positional signal, concentrations are likely to be low enough that, per individual cell, only a few thousand molecules may be involved. Fluctuations to be expected in these numbers (Poisson distribution) could readily lead to errors up to a few percent of embryo length in the reading of position. This is an intolerable level of error for some developmental pattern-forming events. Embryos must have means of suppressing such errors. We maintain that this requires communication between cells, and illustrate this by using the reaction part of two well-known Turing-type reaction–diffusion models as the local gradient reader. We show that switching on diffusion in these models leads to adequate suppression of positional errors., Peer-reviewed article, Published. Received 31 December 1997, Revised 20 July 1998, Accepted 21 July 1998, Available online 24 March 1999.
Suppression of Rho-kinase activity promotes axonal growth on inhibitory CNS substrates
Several molecules inhibit axonal growth cones and may account for the failure of central nervous system regeneration, including myelin proteins and various chondroitan sulfate proteoglycans expressed at the site of injury. Axonal growth inhibition by myelin and chondroitan sulfate proteoglycans may in part be controlled by Rho-GTPase, which mediates growth cone collapse. Here, we tested in vitro whether pharmacological inhibition of a major downstream effector of Rho, Rho-kinase, promotes axonal outgrowth from dorsal root ganglia grown on aggrecan. Aggrecan substrates stimulated Rho activity and were inhibitory to axonal growth. Y-27632 treatment promoted the growth of axons by 5- to 10-fold and induced “steamlined” growth cones with longer filopodia and smaller lamellipodia. Interestingly, more actin bundles reminiscent of stress fibers in the central domain of the growth cone were observed when grown on aggrecan compared to laminin. In addition, Y-27632 significantly promoted axonal growth on both myelin and adult rat spinal cord cryosections. Our data suggest that suppression of Rho-kinase activity may enhance axonal regeneration in the central nervous system., Peer-reviewed article, Published. Received 2 July 2002; Revised 24 October 2002; Accepted 28 October 2002; Available online 23 March 2003.
A survey of stakeholder perspectives on exoskeleton technology
Background Exoskeleton technology has potential benefits for wheelchair users' health and mobility. However, there are practical barriers to their everyday use as a mobility device. To further understand potential exoskeleton use, and facilitate the development of new technologies, a study was undertaken to explore perspectives of wheelchair users and healthcare professionals on reasons for use of exoskeleton technology, and the importance of a variety of device characteristics. Methods An online survey with quantitative and qualitative components was conducted with wheelchair users and healthcare professionals working directly with individuals with mobility impairments. Respondents rated whether they would use or recommend an exoskeleton for four potential reasons. Seventeen design features were rated and compared in terms of their importance. An exploratory factor analysis was conducted to categorize the 17 design features into meaningful groupings. Content analysis was used to identify themes for the open ended questions regarding reasons for use of an exoskeleton. Results 481 survey responses were analyzed, 354 from wheelchair users and 127 from healthcare professionals. The most highly rated reason for potential use or recommendation of an exoskeleton was health benefits. Of the 17 design features, 4 had a median rating of very important: minimization of falls risk, comfort, repair and maintenance cost, and purchase cost. Factor analysis identified two main categories of design features: Functional Activities and Technology Characteristics. Qualitative findings indicated that health and physical benefits, use for activity and access reasons, and psychosocial benefits were important considerations in whether to use or recommend an exoskeleton. Conclusions This study emphasizes the importance of developing future exoskeletons that are comfortable, affordable, minimize fall risk, and enable functional activities. Findings from this study can be utilized to inform the priorities for future development of this technology., Peer-reviewed article, Published. Submission date 13 September 2014 ; Acceptance date 12 December 2014 ; Publication date 19 December 2014.
Synthesis of galactofuranosyl-containing oligosaccharides corresponding to the glycosylinositolphospholipid of Trypanosomacruzi
The oligosaccharide β-d-Galf-(1→3)-α-d-Manp-(1→2)-[β-d-Galf-(1→3)]-α-d-Manp-(1→2)-α-d-Manp corresponds to the terminal end of the glycosylinositolphospholipid oligosaccharide of the protozoan Trypanosomacruzi, the causative agent of Chagas’ disease. Syntheses of methyl or ethylthio glycosides of the terminal disaccharide, trisaccharide, tetrasaccharide, and pentasaccharide corresponding to this structure are described. These syntheses employ the selective activation of a phenyl 1-selenogalactofuranoside or a phenyl 1-selenomannopyranoside donor over ethyl 1-thioglycoside acceptors with NIS–TfOH., Peer-reviewed article, Published. Received 8 December 1999; Accepted 14 December 1999; Available online 19 April 2000.
Taxonomizing features and methods for identifying at-risk students in computing courses
Proceedings from the 23rd Annual ACM Conference on Innovation and Technology in Computer Science Education. Since computing education began, we have sought to learn why students struggle in computer science and how to identify these at-risk students as early as possible. Due to the increasing availability of instrumented coding tools in introductory CS courses, the amount of direct observational data of student working patterns has increased significantly in the past decade, leading to a flurry of attempts to identify at-risk students using data mining techniques on code artifacts. The goal of this work is to produce a systematic literature review to describe the breadth of work being done on the identification of at-risk students in computing courses. In addition to the review itself, which will summarize key areas of work being completed in the field, we will present a taxonomy (based on data sources, methods, and contexts) to classify work in the area., Peer reviewed, Conference paper, Published.
Temperature and air flow patterns in attic roofs
Understanding temperature and airflow patterns in an attic roof helps to identify the sections of the roof where moisture damage and roofing material durability problems can be expected. In this paper, the temperature distribution and the airflow patterns inside an attic space in a climate that can be characterized with cold winter and hot summer periods are discussed. In the study, transient boundary conditions were applied, and the dynamic responses of a typical attic roof, including the flow patterns, attic air and roof sheathing temperatures, ventilation rates, and heating and cooling loads, are presented. These findings can be used to understand the airflow pattern and how it can be affected by an incoming wind speed and solar gain., Peer reviewed article, Published. Received: September 14, 2016; Accepted: March 08, 2017; Published online: June 22, 2017.
Temperature and humidity distributions in mid-rise residential building suites
14th Canadian Conference on Building Science and Technology, Toronto, Canada, October 29th-30th, 2014. It is essential to design and operate buildings with good indoor air quality as people spend most of their time indoor. Their productivity, comfort and health depend on the quality of the indoor air. In addition to other air quality parameters, indoor humidity and temperature need to be controlled and maintained to acceptable ranges. These conditions may not be uniform within the house/building due to local heat and moisture sources and absence of an effective indoor air mixing mechanism as in the case of in buildings with baseboard heating systems. Localized high humidity creates favourable conditions for localized mold growth, poor indoor air quality and building envelope damage. In this paper, the indoor humidity and temperature distributions within four suites (designated as Suite ‘A’, ‘B’, ‘C’ and ‘D’) in a six-storey multi-residential building are studied. A total of 22 rooms are monitored with indoor temperature and relative humidity data loggers, and the outdoor climatic conditions are measured with a weather station for over a year. The hygrothermal performances of exterior walls in the master bedrooms of the respective suites are assessed. Analysis of the measured data suggests that the temperature variations between the rooms (bedrooms, living room, kitchen excluding bathroom) are relatively low during the summer period (mean temperature difference less than 1oC) compared to the winter period where the variations between the rooms can be as high as 2oC. The excess humidity differences between the rooms, excluding the kitchens, are in the range of 0.2 g/m 3 to 1.0 g/m 3 during both winter and summer periods, whereas the excess humidity fluctuations within the rooms are fairly the same and have standard deviation values between 0.8 g/m 3 and 1.0 g/m 3. Excess humidity is defined as the difference between the indoor and outdoor absolute humidities, quantities that are derived from the simultaneously measured temperature and relative humidity of the indoor and outdoor locations. Hygrothermal simulation results of exterior wall systems indicate that, in a mild coastal climate, the winter average indoor relative humidity shall be below 43% (for a seasonal average indoor temperature of 20oC) to avoid building envelope moisture damage., Peer reviewed article, Published.
Thermostat setback effect in whole building performance
Proceedings of Building Physics Symposium: 29 October 2008, Leuven, Belgium. This paper describes the use of a whole building hygrothermal model (HAMFitPlus) to analyze the energy savings resulting from three programmable thermostat setting schemes in a real occupied residential house. It discusses the effect of these schemes on the indoor relative humidity and moisture performance. In the first thermostat-setting scheme, the indoor temperature is maintained constant at 21 at all time (no set-back). In the second thermostat-setting scheme, the indoor temperature is maintained at 21ºC from 7:00 to 21:00 h, and then setback to 17ºC for the remaining hours (21:00 to 7:00 h)., Conference paper, Published. A version of this document is published in: Building Physics Symposium, Lueven, Belgium, October 29-31, 2008, pp. 1-5.
Towards gender diversity in Computer Science postsecondary education
Proceedings from AERA 2018 Conference, 12 pp., New-York, NY, USA., Peer reviewed, Conference paper, Gender studies, Postsecondary education, Women's issues
Transcriptional bursting in drosophila development
Anterior-posterior (AP) body segmentation of the fruit fly (Drosophila) is first seen in the 7-stripe spatial expression patterns of the pair-rule genes, which regulate downstream genes determining specific segment identities. Regulation of pair-rule expression has been extensively studied for the even-skipped (eve) gene. Recent live imaging, of a reporter for the 2nd eve stripe, has demonstrated the stochastic nature of this process, with ‘bursts’ in the number of RNA transcripts being made over time. We developed a stochastic model of the spatial and temporal expression of eve stripe 2 (binding by transcriptional activators (Bicoid and Hunchback proteins) and repressors (Giant and Krüppel proteins), transcriptional initiation and termination; with all rate parameters constrained by features of the experimental data) in order to analyze the noisy experimental time series and test hypotheses for how eve transcription is regulated. These include whether eve transcription is simply OFF or ON, with a single ON rate, or whether it proceeds by a more complex mechanism, with multiple ON rates. We find that both mechanisms can produce long (multi-minute) RNA bursts, but that the short-time (minute-to-minute) statistics of the data is indicative of eve being transcribed with at least two distinct ON rates, consistent with data on the joint activation of eve by Bicoid and Hunchback. We also predict distinct statistical signatures for cases in which eve is repressed (e.g. along the edges of the stripe) vs. cases in which activation is reduced (e.g. by mutagenesis of transcription factor binding sites). Fundamental developmental processes such as gene transcription are intrinsically noisy; our approach presents a new way to quantify and analyze time series data during developmental patterning in order to understand regulatory mechanisms and how they propagate noise and impact embryonic robustness., Peer-reviewed article, Published. Received: November 21, 2016; Accepted: April 8, 2017; Published: April 24, 2017.
Transient model for coupled heat, air and moisture transfer through multilayered porous media
Most building materials are porous, composed of solid matrix and pores. The time varying indoor and outdoor climatic conditions result heat, air and moisture (HAM) transfer across building enclosures. In this paper, a transient model that solves the coupled heat, air and moisture transfer through multilayered porous media is developed and benchmarked using internationally published analytical, numerical and experimental test cases. The good agreements obtained with the respective test cases suggest that the model can be used to assess the hygrothermal performance of building envelope components as well as to simulate the dynamic moisture absorption and release of moisture buffering materials., Peer reviewed article, Published. Received 26 February 2009, Revised 30 September 2009, Accepted 1 October 2009, Available online 13 April 2010.
Treatment of douglas-fir heartwood thermomechanical pulp with laccases
Douglas-fir heartwood thermomechanical pulp was treated with laccase enzymes at 25 and 50°C with and without added oxygen. The treated pulps were cleached with hudrogen peroxide at increasing alkali charges. Laccase treatments without added oxygen increased bleached brightness by 1.5-2.5 pts ISO, and decreased hydrogen peroxide consumption by 15-20%. The enzyme treatments were not enhanced when supplemented with oxygen. When the effectiveness of four different laccase enzymes was compared for the treatment of Douglas-fir heartwood thermomechanical pulp, there were no significant differences found in the performance among the enzymes. Possible explanations for the observed results are given., Peer-reviewed article, Published.
Trust-sensitive belief revision
Proceedings of the Twenty-Fourth International Joint Conference on Artificial Intelligence in Buenos Aires, Argentina, 25–31 July 2015. Belief revision is concerned with incorporating new information into a pre-existing set of beliefs. When the new information comes from another agent, we must first determine if that agent should be trusted. In this paper, we define trust as a pre-processing step before revision. We emphasize that trust in an agent is often restricted to a particular domain of expertise. We demonstrate that this form of trust can be captured by associating a state partition with each agent, then relativizing all reports to this partition before revising. We position the resulting family of trust-sensitive revision operators within the class of selective revision operators of Ferme and Hansson, and we examine its properties. In particular, we show how trust-sensitive revision is manipulable, in the sense that agents can sometimes have incentive to pass on misleading information. When multiple reporting agents are involved, we use a distance function over states to represent differing degrees of trust; this ensures that the most trusted reports will be believed., Conference paper, Published.
The tyranny of chronological age
This paper presents an analysis of a phenomenon known as "The Relative Age" effect. When assessing the innate ability (or talent) of individual children who are grouped into age cohorts, systematic errors occur due to differences in biological maturity. A structural model of a multi-period progression through levels (or grades) that employs screening and selection is developed. Through a series of simulations, impact of the relative age on the of selection process is analyzed., Thesis, Draft published.

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