BCIT Citations Collection | BCIT Institutional Repository

BCIT Citations Collection

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Collection of published works from BCIT researchers, faculty, and instructors.

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An explicit model of belief change for cryptographic protocol verification
Proceedings of the 8th International Symposium on Logical Formalizations of Commonsense Reasoning. Stanford, CA, 2007. Cryptographic protocols are structured sequences of messages that are used for exchanging information in a hostile environment. Many protocols have epistemic goals: a successful run of the protocol is intended to cause a participant to hold certain beliefs. As such, epistemic logics have been employed for the verification of cryptographic protocols. Although this approach to verification is explicitly concerned with changing beliefs, formal belief change operators have not been incorporated in previous work. In this preliminary paper, we introduce a new approach to protocol verification by combining a monotonic logic with a non-monotonic belief change operator. In this context, a protocol participant is able to retract beliefs in response to new information and a protocol participant is able to postulate the most plausible event explaining new information. Hence, protocol participants may draw conclusions from received messages in the same manner conclusions are drawn in formalizations of commonsense reasoning. We illustrate that this kind of reasoning is particularly important when protocol participants have incorrect beliefs., Conference paper, Published.
Exploiting known vulnerabilities of a smart thermostat
Proceedings of 2016 14th Annual Conference on Privacy, Security and Trust (PST) in Auckland, New Zealand, 12-14 Dec. 2016. We address security vulnerabilities for a smart thermostat. As this kind of smart appliance is adopted in homes around the world, every user will be opening up a new avenue for cyber attack. Since these devices have known vulnerabilities and they are being managed by non-technical users, we anticipate that smart thermostats are likely to be targetted by unsophisticated attackers relying on publicly available exploits to take advantage of weakly protected devices. As such, in this paper, we take the role of a `script kiddy' and we assess the security of a smart thermostat by using Internet resources for attacks at both the physical level and the network level. We demonstrate that such attacks are unlikely to be effective without some additional social engineering to obtain user credentials. Moreover, we suggest that the vulnerability to attack can be further minimized by simply reducing the use of remote storage where possible., Conference paper
Exploring power storage profiles for vehicle to grid systems
Proceedings of the AAAI Workshop on Artificial Intelligence for Cities, Austin, USA, 2015. The Smart Grid allows users to monitor power usage through the use of Smart Meter technology. In principle, this information can be used to modify usage habits in a way that reduces consumer costs as well as greenhouse emissions. However, in an urban environment, many users are restricted by the same constaints: they work during the day, and they are home at night. This creates spikes in power cost at peak usage times, and it may also lead to increased emissions in scenarios where sustainable resources are limited. An individual user can avoid these spikes by using an electric car as a storage device; it can be charged at the cheapest times, and then discharged to the home at the most expensive times. While this idea is intuitively appealing, it turns out that the benefits vary greatly depending on the storage algorithm used. In this paper, we describe the Power Storage Simulator, a tool for experimenting with storage algorithms to improve the efficiency of vehicle to grid systems. We suggest that this tool is also useful for educating power consumers about load balancing on the Smart Grid through an engaging, visual simulation., Conference paper, Published.
Feasibility of sensory tongue stimulation combined with task-specific therapy in people with spinal cord injury
Background Previous evidence suggests the effects of task-specific therapy can be further enhanced when sensory stimulation is combined with motor practice. Sensory tongue stimulation is thought to facilitate activation of regions in the brain that are important for balance and gait. Improvements in balance and gait have significant implications for functional mobility for people with incomplete spinal cord injury (iSCI). The aim of this case study was to evaluate the feasibility of a lab- and home-based program combining sensory tongue stimulation with balance and gait training on functional outcomes in people with iSCI. Methods Two male participants (S1 and S2) with chronic motor iSCI completed 12 weeks of balance and gait training (3 lab and 2 home based sessions per week) combined with sensory tongue stimulation using the Portable Neuromodulation Stimulator (PoNS). Laboratory based training involved 20 minutes of standing balance with eyes closed and 30 minutes of body-weight support treadmill walking. Home based sessions consisted of balancing with eyes open and walking with parallel bars or a walker for up to 20 minutes each. Subjects continued daily at-home training for an additional 12 weeks as follow-up. Results Both subjects were able to complete a minimum of 83% of the training sessions. Standing balance with eyes closed increased from 0.2 to 4.0 minutes and 0.0 to 0.2 minutes for S1 and S2, respectively. Balance confidence also improved at follow-up after the home-based program. Over ground walking speed improved by 0.14 m/s for S1 and 0.07 m/s for S2, and skilled walking function improved by 60% and 21% for S1 and S2, respectively. Conclusions Sensory tongue stimulation combined with task-specific training may be a feasible method for improving balance and gait in people with iSCI. Our findings warrant further controlled studies to determine the added benefits of sensory tongue stimulation to rehabilitation training., Peer-reviewed article, Published. Received: 10 July 2013 ; Accepted: 2 June 2014 ; Published: 6 June 2014.
Fibroblast growth factor treatment produces differential effects on survival and neurite outgrowth from identified bulbospinal neurons in vitro
The in vivo application of appropriate trophic factors may enhance regeneration of bulbospinal projections after spinal cord injury. Currently, little is known about the sensitivities of specific bulbospinal neuron populations to the many identified trophic factors. We devised novel in vitro assays to study trophic effects on the survival and neurite outgrowth of identified bulbospinal neurons. Carbocyanine dye crystals implanted into the cervical spinal cord of embryonic day (E)5 chick embryos retrogradely labeled developing bulbospinal neurons. On E8, dissociated cultures containing labeled bulbospinal neurons were prepared. Fibroblast growth factor (FGF)-2 (but not FGF-1) promoted the survival of bulbospinal neurons. FGF receptor expression was widespread in the E8 brainstem, but not detected in young bulbospinal neurons, suggesting that nonneuronal cells mediated the FGF-stimulated survival response. Astrocytes synthesize a variety of trophic factors, and astrocyte-conditioned medium (ACM) also promoted the survival of bulbospinal neurons. As might be expected, FGF-2 function blocking antibodies did not suppress ACM-promoted survival, nor did an ELISA detect FGF-2 in ACM. This suggests that nonneuronal cells synthesize other factors in response to exogenous FGF-2 which promote the survival of bulbospinal neurons. Focusing on vestibulospinal neurons, dissociated (survival assay) or explant (neurite outgrowth assay) cultures were prepared. FGF-2 promoted both survival and neurite outgrowth of identified vestibulospinal neurons. Interestingly, FGF-1 promoted neurite outgrowth but not survival; the converse was true of FGF-9. Thus, differential effects of specific growth factors on survival or neurite outgrowth of bulbospinal neurons were distinguished., Peer-reviewed article, Published. Received 10 September 1999; Accepted 18 January 2000; Available online 25 May 2002.
Functional level assessment of individuals with transtibial limb loss
The functional level (K level) of prosthetic users is used to choose appropriate prosthetic components, but ratings may highly subjective. A more objective and robust method to determine K level may be appealing. The aim of this study was to determine the relationship between K level determined in the clinic to K level based on real world ambulatory activity data collected by StepWatch. Twelve individuals with transtibial limb loss gave informed consent to participate. K level assessments performed in the clinic by a single treating prosthetist were compared with a calculated estimate based on seven days of real world ambulatory activity patterns using linear regression. There was good agreement between the two methods of determining K level with R2 = 0.775 (p < 0.001). The calculated estimate of K level based on actual ambulatory activity in real world settings appears to be similar to the treating prosthetist’s assessment of K level based on gait observation and patient responses in the clinic. Clinic-based ambulatory capacity in transtibial prosthetic users appears to correlate with real world ambulatory behavior in this small cohort. Determining functional level based on real world ambulatory activity may supplement clinic-based tests of functional capacity., Peer-reviewed article, Published. Date received: 2 December 2015; Accepted: 20 January 2016; First Published March 9, 2016.
A functional task analysis and motion simulation for the development of a powered upper-limb orthosis
Describes research work directed towards the development and application of a design methodology to determine the optimal configuration of a powered upper-limb orthosis. The design objective was to minimize the orthosis complexity, defined as the number of degrees of freedom, while maintaining the ability to perform specific tasks. This objective was achieved in three stages. First, potential users of a powered orthosis were interviewed to determine their priority tasks. Secondly, the natural arm motions of able-bodied individuals performing the priority tasks were profiled using a video tracking system. Finally, a kinematic simulation algorithm was developed and employed in order to evaluate whether a proposed orthosis configuration could perform the priority tasks. The research results indicate that task functionality is overly compromised for orthosis configurations with less than five degrees of freedom, plus prehension. Acceptable task performance, based on the specific priority tasks considered, was achieved in the simulations of two different orthosis configurations with five degrees of freedom. In the first design option, elevation (rotation about a horizontal axis through the shoulder) and radial/ulnar deviation are fixed, while in the second option wrist flexion and radial/ulnar deviation are fixed. A prototype orthosis is currently being developed using the first design option., Peer-reviewed article, Published.
Fundamental methods of mathematical economics
4th edition., Book, Published.
Getting serious about sustainability
One-planet living represents the per capita share of global ecosystem services that each person on Earth could use were humanity to live equitably within ecological carrying capacity. My research uses ecological footprint analysis to explore the potential for the City of Vancouver to achieve one-planet living. Specifically, I examine what reductions in per capita ecological footprint would be necessary, what policies or changes to management practices are available to the City to facilitate those reductions, and what one-planet living might “look like” if those policies and changes to urban management practices were implemented. I use 2006 data to conduct an integrated urban metabolism and ecological footprint assessment for the City in order to establish a baseline from which to estimate the necessary reductions in material and energy consumption. I develop lifestyle archetypes of societies living at a one-planet ecological footprint (both real and hypothetical) to inform estimates on how changes in diet, buildings, consumables and waste, transportation and water could achieve one-planet living in Vancouver. I also draw on examples from the international sustainable cities literature and interviews with City of Vancouver and Metro Vancouver staff and elected representatives to develop policy proposals for reducing Vancouver’s ecological footprint. Getting to one-planet living in Vancouver requires at least a 58% reduction in the per capita ecological footprint with the greatest contributions coming from reducing food waste, red meat consumption, and virtually eliminating personal motor vehicle use (shifting instead to an 86% walk, cycle and transit mode share which the City already achieves in its Downtown). The City has and can continue to influence individual and corporate choices through zoning and permitting. However, citizens would have to accept lifestyle changes pertaining to food and personal consumption to achieve the one-planet living goal. Involvement by senior governments in reducing the ecological footprint is also required. It remains to be seen whether Vancouverites, or any population accustomed to modern consumer lifestyles, will voluntarily accept and implement the changes necessary to achieve equitable sustainability as articulated by one-planet living., Thesis, Published.
A greenhouse gas emissions inventory and ecological footprint analysis of Metro Vancouver residents’ air travel
Ecological Footprint Analysis (EFA) at the city or regional scale does not typically include air travel due to a lack of readily available data. However, knowing the “load” placed on nature by various lifestyle choices, including air travel, is essential if we hope to enable society to live sustainably within ecological limits. This paper provides methods for including air travel in urban EFA, in a manner that is accessible to those that are interested in the complexities of urban sustainability. Our goal is to use the case of the Vancouver Metropolitan region to illustrate two methods in such a way that they can be replicated or adapted for use in other cities and regions. We found that the greenhouse gas emissions of air travel by Metro Vancouver residents for 2006 is between 1,191,070 and 1,402,420 tonnes of carbon dioxide equivalent (tCO2e). The resulting ecological footprint is between 287,030 and 337,980 global hectares (gha), or between 0.136 and 0.160 gha/capita. The dedicated carbon sink required to neutralize the carbon dioxide emissions from Metro Vancouver residents’ air travel alone is equivalent to twice the land area of the region (283,183 hectares)., Peer-reviewed article, Published. Received: July 15, 2013 ; Accepted: September 16, 2013 ; Online Published: September 27, 2013.
Heat, air and moisture transport properties of several North American bricks and mortar mixes
Hygrothermal models are emerging as practical building design tools. These models require a set of reliable inputs to provide results that are meaningful to the designers. One of these inputs is the set of heat, air and moisture transport properties of materials. For any given class of building materials the properties may vary within a broad range. This paper reports the porosity, density, matrix density, thermal conductivity, equilibrium moisture content, water vapor permeability, water absorption coefficient, liquid diffusivity and air permeability of six types of bricks and four mortar mixes that are commonly used in North America. The experimental and analytical procedures follow either international standards or well-established methodologies., Peer reviewed article, Published. Received 9 July 2003; accepted 17 March 2004.
Heat, air and moisture transport properties of three North American stuccos
Heat, air, and moisture transfer models that are used as practical building design tools require reliable inputs to provide meaningful results. One of these inputs is the set of heat, air, and moisture transport properties of materials. For any given class of building materials the properties may vary within a broad range. This paper reports the porosity, density, matrix density, thermal conductivity, equilibrium moisture content, water vapor permeability, water absorption coefficient, liquid diffusivity, and air permeability of regular lime stucco, regular Portland cement stucco, and acrylic stucco that are commonly used in North America. The experimental and analytical procedures follow either international standards or well-established methodologies., Peer reviewed article, Published. Received 9 January 2004; accepted 13 October 2005; published online 25 January 2006.
Hedging the risk of increased emissions in long term energy planning
The feasibility of meeting emission targets is often evaluated using long range planning optimization models in which the targets are incorporated into the system constraints. These models typically provide one ‘optimal’ solution that considers only a deterministic representative value of emissions for each technology and do not consider the risk of exceeding expected emissions for a given optimal solution. Since actual emissions for any given technology are uncertain, implementation of such an optimal solution carries inherent risk that emissions will exceed the given target. In this paper, we implement a stochastic risk structure into the OSeMOSYS optimization model to incorporate uncertainty related to the emissions of electricity generation technologies. For a given risk premium, defined as the additional amount that society is willing to pay to reduce the risk of exceeding the cost optimal system emissions, we determine the generation technology mix that has the lowest risk of exceeding this baseline. We focus on emissions risk since the literature on emissions risk is sparse while the literature on other risks such as policy risks, financial risks and technological risks is extensive. We apply the model to a case study of a primarily fossil based jurisdiction and find that, when risk is incorporated, solar and wind technologies are built out seven and five years earlier respectively and that carbon free technologies such as coal with carbon capture and storage (CCS) become effective alternatives in the energy mix when compared to the ‘optimal’ solution without consideration of risk, though this does not include the risk of carbon leakage from CCS technologies. If nuclear is included as a generation option, we find that nuclear provides an effective risk hedge against exceeding emissions., Peer-Reviewed Article, Final article published. Available online 12 February 2017., Peer reviewed
Hygrothermal modeling of aerated concrete wall and comparison with field experiment
Proceedings of 3rd International Building Physics Conference: 27 August 2006, Montreal, QC. A two-dimensional heat, air and moisture transport model called hygIRC is adapted to simulate a well-documented field exposure of an aerated concrete wall section. Difficulties are encountered due to a few missing information on boundary conditions of the exposure and hygrothermal properties of aerated con-crete. The paper presents how these inadequacies were overcome to simulate the hygrothermal behavior of the wall section. Appropriate assumptions were made due to justifiable reasons. Then the model provides temporal and spatial distributions of temperature and relative humidity for an extended period that are in ex-cellent agreement with the documented field data. The paper presents the justifications for the assumptions and the comparison of experimental and simulation results., Conference paper, Published. A version of this document is published in: 3rd International Building Physics Conference, Montreal, QC., August 27, 2006, pp. 321-328.
Hygrothermal performance assessment of vented and ventilated wall systems
Proceedings of Thermal Performance of the Exterior Envelopes of Whole Buildings XII International Conference, At Clearwater Beach, Florida, USA, December 2013. Based on analysis of the drying and wetting potentials of a particular local climate, designers choose wall systems with or without an air gap between a sheathing membrane and a cladding layer. In addition to the capillary break that the air gap provides, thereby reducing the moisture transfer from wet cladding to the interior of the wall, the airspace will add the thermal resistance of the wall system and reduce the heat flow across the wall system. These moisture and thermal performances are straightforward to understand if the air in the air cavity is assumed to be a “still air.” In this paper, an experimental study is undertaken to under-stand the impact of airflow through an air cavity on the moisture and thermal performance of wall systems. To achieve this objective three test panels are instrumented and monitored in the field-experimental setting: one with no air gap, another one with an air gap but restricted airflow, and the third one with an air gap and open for airflow. The second and third wall systems have the same air gap width but different top flashing designs creating vented and ventilated wall systems. For the wall systems’ orientation and boundary conditions considered in this study, the wall with no air gap accumulates relatively high moisture content on the sheathing board, stud, and bottom plate and also has high moisture content changes in a year cycle when compared to the vented and ventilated wall systems. In general, the hygrothermal performances of vented and ventilated wall systems are comparable. During the winter period when relatively high moisture accumulation occurs, the upper section of the ventilated wall system shows slightly lower moisture content compared to that of the vented wall system. The temperature readings of the sheathing boards in the vented and ventilated wall systems are slightly warmer than that of the wall with no air gap for 85.5% and 73% of the time (based on hourly data of a year), respectively. For the balance of a period of time, the sheathing boards in the walls with an air cavity are slightly cooler than that of the wall with an air gap. Although the low temperature on the sheathing board, which is caused by solar radiation-induced airflow, is beneficial during a cooling season, the air gap and the associated airflow may reduce the heat gain that may be obtained from solar radiation during the heating season. The implications of air cavity and flashing design (airflow rate) on the heating and cooling load calculations of different orientations, wall configurations, and climate require further investigation., Conference paper, Published.
Hygrothermal performance of exterior wall systems using an innovative vapour retarder in Canadian climate
Proceeding of the 4th International Building Physics Conference: 15 June 2009, Istanbul, Turkey. This paper provides highlights of the research work carried out at the National Research Council Canada, Institute for Research in Construction on assessing the hygrothermal performance of wall systems that included this innovative vapour retarder (Note: Vapour Barrier in Canadian terminology is equivalent to Vapor retarder in US terminology). The performance of walls was assessed when subjected to eastern coastal climate conditions of Halifax, one of the four Canadian climatic locations used in this study. A wood-framed stucco clad wall was the reference assembly. Results from different cases based on the variation of vapour control strategies and their effect on the hygrothermal performance of the wall systems are analysed. The results for the Halifax climate location indicate that the installation of a humidity controlled, innovative vapour retarder is a recommendable solution for the envelope design of residential buildings of these locations with moderate or high water vapour permeance of the interior paint. In this study, the advanced hygrothermal tool, hygIRC, was used to perform the hygrothermal performance analysis of the wall systems., Peer reviewed article, Published. A version of this document is published in: 4th International Building Physics Conference, Istanbul, Turkey, June 15-18, 2009, pp. 1-8.

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