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An IoT Architecture for Ubiquitous Context-Aware Assessments
No full textA Master of Science thesis in Computer Engineering by Salsabeel Yousef Shapsough entitled, "An IoT Architecture for Ubiquitous Context-Aware Assessments," submitted in May 2017. Thesis advisor is Dr. Imran Zualkernan. Soft and hard copy available.Ubiquitous learning environments aim to move students out of classrooms and into the real world where learners can engage in experiential and tangible learning. Ubiquitous assessment systems are one class of learning environments that enact student learning in the form of teacher, peer, and system-generated assessments that incorporate physical aspects of objects in outdoor locations. A key component of such systems is a wireless-enabled edge device augmented with various types of sensors to represent the state of physical objects and environments. Most such current systems are constructed using traditional Internet technologies which are not suited for this purpose and hence leading to cumbersome and complex designs. This thesis presents a novel generic technical architecture for such systems built around Internet of Things (IoT) computing platforms. The newly proposed architecture is designed to seamlessly incorporate various IoT communication protocols. A commonly used IoT edge device was used to implement four variants of the proposed architecture. The variants based on Advanced Message Queuing Protocol (AMQP), Constrained Application Protocol (CoAP), Message Queue Telemetry Transport (MQTT), and Extensible Messaging and Presence Protocol (XMPP) IoT protocols were evaluated using an experimental setup. Each implementation was evaluated in terms of power consumption, CPU utilization and RAM usage, as well as end-to-end latency and throughput in response to network disturbances. In addition, qualitative aspects of each implementation were analysed based on maximum message size, overhead, security, reliability, and ease of implementation and flexibility. While there were statistical differences in power consumption between the four implementations, the practical difference was negligible. CoAP proved to be the most efficient in terms of CPU and memory utilization but produced the lowest latency in lagged networks only. However, due to payload limitations and lack of reliability features, CoAP was considered ill-suited for such applications. Among the other three variants, MQTT and AMQP seem more appropriate in terms of qualitative features, although MQTT was more resource efficient in most technical aspects.College of EngineeringDepartment of Computer Science and EngineeringMaster of Science in Computer Engineering (MSCoE
Monitoring and Assessment of Water Quality in Coastal Lake using High Resolution Imagery and GIS
No full textDubai has been an example of rapid development in recent years, adversely affecting water quality in the surrounding areas. One such effect is the reoccurring algal bloom (high chlorophyll-a concentration) in Dubai Creek, a coastal lake in Dubai. The objectives of this study were to retrieve chlorophyll-a from Dubai Sat-1 imagery and to further investigate its relationship to different nutrients in the creek. Spectral models of chlorophyll-a were developed from two DubaiSat-1 images acquired in 2010 and 2011. The models showed high correlation (R-squared values of 87.7%and 89.1%, respectively) with field water quality data collected at the monitoring stations operated by Dubai Municipality. Exploratory Regression (ER) analysis was then performed in GIS to study the relationship between spectral-based chlorophyll-a and nutrients. Although the ER nalysis showed low overall correlation, relatively high R-squared values were obtained at the Sewage Treatment Plant outfall location
Anti-Bacterial and Anti-Fungal Activity of Xanthones Obtained via Semi-Synthetic Modification of α-Mangostin from Garcinia mangostana
No full textThe microbial contamination in food packaging has been a major concern that has paved the way to search for novel, natural anti-microbial agents, such as modified α-mangostin. In the present study, twelve synthetic analogs were obtained through semi-synthetic modification of α-mangostin by Ritter reaction, reduction by palladium-carbon (Pd-C), alkylation, and acetylation. The evaluation of the anti-microbial potential of the synthetic analogs showed higher bactericidal activity than the parent molecule. The anti-microbial studies proved that I E showed high anti-bacterial activity whereas I I showed the highest anti-fungal activity. Due to their microbicidal potential, modified α-mangostin derivatives could be utilized as active anti-microbial agents in materials for the biomedical and food industry
Integrated economic and environmental models for a multi stage cold supply chain under carbon tax regulation
No full textThe elevated level of public and organizations awareness concerning sustainability has necessitated the adoption of environmentally conscious practices in the management of supply chains. As such, classical inventory models wherein the sole measure of performance is cost minimization are no longer appropriate to handle such emerging and pressing issue. This paper assesses the impact of accounting for carbon emissions, resulting from transportation and storage activities of a cold item, in the context of a multi stage supply chain comprised of a plant/warehouse, a distribution center (DC) and a retailer. We present an operational cost minimization model, a carbon footprint minimization model and a hybrid economic and environmental minimization model where all models seek to determine the optimal lot sizing and shipping quantities, alongside the number of trucks to be used in the upstream and downstream directions of the supply chain as well as the number of freezer units utilized at the DC which is owned by a third party logistics provider. The structural properties for the optimal solution of the three models are identified and solution algorithms are also proposed. Upon conducting computational experiments, it turns out that the incorporation of carbon related costs, through carbon tax regulation, may call for adjusting the adopted operational policy which results in a minor increase in the operational cost. However, this increase is outweighed by the savings resulting from the carbon related costs. Numerical results of the sensitivity analysis on the carbon tax policy indicate that as the tax rate increases, substantial reductions in the amount of carbon footprint emitted are realized and cost savings are also achieved when adopting the lot sizing and shipping policy of the third/integrated model over the operational cost minimization model
Effect of Aggregate Type and Specimen Configuration on Concrete Compressive Strength
No full textA Master of Science thesis in Civil Engineering by Doaa Mansour entitled, "Effect of Aggregate Type and Specimen Configuration on Concrete Compressive Strength," submitted in April 2017. Thesis advisor is Dr. Sherif Yehia. Soft and hard copy available.Cement content, water-to-cement ratio (w/c), aggregate size and type, specimen size and shape, loading rate, and curing are some factors that affect the concrete compressive strength. This study focuses on the effect of aggregate type and specimen configuration on the compressive strength of concrete. Six concrete mixes utilizing 10 mm and 20 mm natural, LAYTAG and Pumice lightweight, and recycled aggregate from two sources, "Bee'ah and Jabal Ali", were used to investigate the effect of these two factors. In addition, samples from ready-mix concrete producers with different strengths "C45, C75, C60, and C80" were evaluated for the compressive strength using standard size cylinders and cubes. Strength development was monitored on the 7th, 28th, and 90th day. In addition, flexural strength, split tension, and modulus of elasticity were evaluated on the 28th and 90th day. Statistical analyses were conducted to estimate the relationships among the variables considered in the investigation. Moreover, other mechanical properties as a function of compressive strength were discussed and compared to those predicated by the ACI specification. Results indicate that standard specimen size has a negligible effect on the concrete compressive strength; whereas, specimen shape had a noticeable effect on the compressive strength as the Cylinder/Cube ratio on the 90th day was ranging between 0.781 and 0.929. The concrete compressive strength and modulus of elasticity were significantly affected by the aggregate type. Other mechanical properties, such as flexural strength and split tensile strength, were less affected by the aggregate type which was also confirmed by the values predicted with the ACI equations.College of EngineeringDepartment of Civil EngineeringMaster of Science in Civil Engineering (MSCE
A combined resource allocation framework for PEVs charging stations, renewable energy resources and distributed energy storage systems
No full textThe massive deployment of plug-in electric vehicles (PEVs), renewable energy resources (RES), and distributed energy storage systems (DESS) has gained significant interest under the smart grid vision. However, their special features and operational characteristics have created a paradigm shift in distribution network resource allocation studies. This paper presents a combined model formulation for the concurrent optimal resource allocation of PEVs charging stations, RES and DESS in distribution networks. The formulation employs a general objective function that optimizes the total Annual Cost of Energy (ACOE). The decision variables in the formulation are the locations and capacities of PEVs charging stations, RES, and DESS units. A Markov Chain Monte Carlo (MCMC) simulation model is utilized to account for the uncertainties of PEVs charging demand and output generation of RES units. Also, in order to enhance the accuracy of the resource allocation problem, the coordinated control of PEVs charging, RES output power, and DESS charging/discharging are incorporated in the formulated model. The formulation is decomposed into two interdependent sub-problems and solved using a combination of metaheuristic and deterministic optimization techniques. A sample case study is presented to illustrate the performance of the algorithm.Natural Sciences and Engineering Research Council of Canada (NSERC
Iterative Methods for the Solution of a Steady State Biofilter Model
No full textA Master of Science thesis in Chemical Engineering by Mubarak Sahal Salih entitled, "Iterative Methods for the Solution of a Steady State Biofilter Model," submitted in November 2017. Thesis advisor is Dr. Zarook M. Shareefdeen. Soft and hard copy available.Biofilter modeling helps in understanding the biofiltration process and designing of full-scale biofilters. The biofilter models with complex kinetics do not have analytical solutions and numerical algorithms are typically employed to obtain approximate solutions. Therefore, the primary objective of this work is to utilize two iterative schemes known as the Adomian decomposition method and the Green’s function fixed point iteration method. The proposed iterative schemes were used to find approximate solutions for a biofilter model proposed by Mohseni and Allen with methanol and alpha-pinene being the objective pollutants. The proposed schemes were applied to reproduce the concentration profiles of methanol and alpha-pinene along the biofilter column. The numerical results were compared against experimental data obtained from literature and the original model solutions. For the biofiltration of methanol, both methods were able to provide accurate predictions. As for the biofiltration of alpha-pinene, the Adomian decomposition method was not able to describe the biodegradation of alpha-pinene in the biofilter where the solution deteriorated as we moved away from the entrance region. Unlike the Adomian decomposition method, the Green’s function fixed point iteration method showed excellent prediction of alpha-pinene removal along the biofilter height. Moreover, the performance of the biofilter was tested at various conditions by determining the impact of several parameters on the biofiltration process. The simulation showed that a maximum methanol elimination capacity of 285.15 g.m-3 h-1 was achieved at an inlet loading of 300 g.m-3 h-1. Based on the sensitivity analysis study, it was observed that a complete removal of methanol in the biofilter was accomplished at 50 seconds empty bed residence time, 63 m2.m-3 biofilm surface area, 6.00 10-6 m2.h-1 diffusion coefficient and 0.01 air-biofilm partition coefficient, respectively. In conclusion, the comparison of the results demonstrated higher potential for application of the Green’s function fixed point iteration method over the Adomian decomposition method in solving biofilter models and understanding of the biofiltration process.College of EngineeringDepartment of Chemical EngineeringMaster of Science in Chemical Engineering (MSChE
Struvite Recovery from Anaerobically Digested Dairy Manure: A Review of Application Potential and Hindrances
No full textAnaerobically digested dairy manure is rich in ammonium, orthophosphates, and magnesium, indicating a high potential for struvite recovery. Continuous generation of large amounts of dairy manure plus increasing global interest in anaerobic digestion of dairy manure suggest a huge market for struvite production with anaerobically digested dairy manure. However, the complex chemical composition of digested dairy manure presents hindrances to struvite recovery. This review paper assesses the significance and potential of struvite recovery from anaerobically digested dairy manure, identifies the factors hindering struvite recovery, and discusses the methods to overcome hindrances and the measures to improve phosphorus speciation of dairy manure for struvite formation. This paper proposes using “struvite recovery potential” or Pstruvite based on the least molar activity of struvite component ions in addition to “supersaturation ratio” to identify the potential for struvite recovery. The probable hindrances mainly include high Ca2+ concentration and molar activity ratios of Ca2+: Mg2+ and Ca2+: PO43−, high ionic strength, and high alkalinity. Struvite formation and purity is likely a function of all the interfering variables, rather than just a single factor with digested dairy manure. Potential enhancement measures need to be tested for technical and economic feasibility and applicability to various sources of digested dairy manure. This review paper provides guidance to overcoming the hindrances of digested dairy manure to struvite formation
Micropollutants Removal from Water using Microfiltration Membrane Modified with ZIF-8 Metal Organic Frameworks (MOFs)
No full textA polytetrafluoroethylene (PTFE) double layer microfiltration membrane has been modified with zeolite imidazolate metal organic frameworks-8 (ZIF-8) and tested for micropollutants removal from water. The physical properties of the modified membrane and its removal characteristics are tested using progesterone as a model pollutant. Compared to the unmodified membrane, incorporation of ZIF-8 onto the polymer matrix resulted in close to 40% increase in the membrane adsorption capacity and almost doubling its water permeability which could result in significant reduction in processing specific energy consumption. The membrane maintained near 95% of its original removal efficiency after three regeneration cycles using polyethylene glycol-400. Modeling of the adsorption results agreed satisfactorily with the experimental measurements. The synergy provided by using ZIF-8 particles and the significant regeneration volume reduction ratio demonstrates the effectiveness of the approach for increasing the overall micropollutants removal capacity and allows for its further consideration for development of viable continuous membrane adsorption techniques for decontamination of water resources
A Unified Approach for Probability of Detection Evaluation over Generalised Fading Channels
No full textIn this paper, we revisit energy detection-based spectrum sensing cognitive radio systems operating over generalised fading channels. In particular, we derive closed-form exact expressions as well as lowand high-signal-to-noise ratio asymptotic expansions for the misdetection probability over the Fox's H-function fading channel. The closed-form expression is given in terms of the bivariate Fox's Hfunction and subsumes most of the expressions previously presented in the literature. Also, the obtained asymptotic expressions are very easy to compute and can be used to get various performance insights. We verified, theoretically and numerically, the validity of the exact expression for important special cases previously reported in the literature, namely the Nakagami-m and the extended generalised-K (EGK) fading distributions. Numerical results also demonstrate the high accuracy of the asymptotic expansions