Schulich School of Engineering Research & Publications
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Item Open Access On Impedance-Pattern Selection for Noise Parameter Measurement(IEEE, 2016-01) Himmelfarb, Michael; Belostotski, LeonidSeveral signal-source impedances (admittances) are required to fully characterize the noise behavior of a linear device. This paper expands the theory of choosing admittances required for noise parameter extraction by finding sets that are guaranteed to form systems of linearly independent equations. A minimal set of four admittances is chosen from four linearly independent admittance regions. Most prior methods require a least-squares solution to noise parameters, using a redundant number of admittances. The proposed method employs a direct solution to the noise parameters using the four admittances. The proposed method also allows adapting the four admittances to overcome signal-source admittance-tuner frequency limitations and/or reducing uncertainty in the minimum noise factor extraction provided approximate knowledge of optimal admittance for minimum noise. The measurement and simulation results demonstrated that the adaptable selection criterion extracted noise parameters well within 3σ uncertainties of noise parameters found with patterns previously reported in literature. Measurements and theory in this work demonstrate that, in general, absolute reflection coefficients of source admittances do not need to exceed approximately 0.4 but should also be less than 0.9. The flexibility of selecting the signal-source admittances has immediate advantages in accurately determining noise parameters of conditionally stable amplifiers, low-frequency devices operating beyond the tuner specifications, devices operating at high frequencies where tuner losses are high, minimizing measurement time, and cases where available admittances do not encompass regions required by other methods.Item Open Access Noise Parameters of Gilbert Cell Mixers(IEEE, 2016-10) Himmelfarb, Michael; Belostotski, LeonidThis paper describes a method for characterizing mixer noise in terms of several noise parameters. A measurement method for extracting the noise parameters is proposed and verified with simulations of a mixer and measurements of two mixers. Direct measurements of single-sideband noise figures are accurately represented by the measured noise parameters, which fully characterize the noise figure of the mixers for all harmonic impedance loading conditions. Over 606 measurements, the maximum error between the measured and modeled noise factors was less than 0.12 dB. This is the first paper that proposes and verifies a method of mixer noise parameter measurements.Item Open Access Noise Performance of a Phased-Array Feed With CMOS Low-Noise Amplifiers(IEEE, 2016-02) Beaulieu, Aaron; Belostotski, Leonid; Burgess, Tom; Veidt, Bruce; Haslett, JamesThe University of Calgary and the National Research Council (NRC) of Canada are developing a low-noise ambient-temperature phased-array demonstrator for possible use in the Square Kilometer Array radio telescope. In December 2014, NRC made noise measurements of the Advanced Focal Array Demonstrator equipped with CMOS low noise amplifiers (LNAs) designed by the University of Calgary. The LNAs were specifically designed for the antenna array operating in the range from 0.7 to 1.5 GHz. Array beam-equivalent noise measurements, using an ambient load as a hot load and the sky as a cold load, show array beam-equivalent noise temperatures as low as 20 K.Item Open Access 5-bit 5-GS/s Noninterleaved Time-Based ADC in 65-nm CMOS for Radio-Astronomy Applications(IEEE, 2016-12) Xu, Yongsheng; Wu, Ge; Belostotski, Leonid; Haslett, JamesThis paper presents a 5-bit noninterleaved time-based analog-to-digital converter (ADC), which operates at a 5-GS/s rate. The ADC is designed for the use in radio-astronomy telescopes, for which time interleaving is not acceptable. The ADC employs a dynamic, differential voltage-to-time converter, a folded-flash time-to-digital converter (TDC), and calibration circuitry. To generate reference delays, the calibration circuitry utilizes a delay-time reference network, which is designed to map the input voltage range into 16 equal time intervals that are used for the calibration of the TDC. The 65-nm CMOS ADC achieves the Signal-to-noise plus distortion ratio/spurious-free dynamic range of 27/32 dB at Nyquist, an effective number of bits (ENOB) of 4.7 bit at low frequencies and 4.1 bit at high frequencies with a power consumption of 21.5 mW at Nyquist.Item Metadata only MOF/MWCNT–Nanocomposite Manipulates High Selectivity to Gas via Different Adsorption Sites with Varying Electron Affinity: A Study in Methane Detection in Parts-per-Billion(ACS, 2022-12-12) Homayoonnia, Setareh; Phani, Arindam; Kim, SeonghwanMetal-organic-frameworks (MOFs) present specific adsorption sites with varying electron affinity which are uniquely conducive to selective gas sensing but are typically large band-gap insulators. In contrary, multiwall-carbon-nanotubes (MWCNTs) exhibit superior mesoscopic transport exploiting strong electron correlations among sub-bands below and above the Fermi level at room temperature. We synergize them in a new-class of nanocomposite based on zeolitic imidazolate framework–8 (ZIF-8) and report selective sensing of CH4 in ~10 parts-per-billion (ppb) with a determined limit of detection of ~0.22 ppb, hitherto unprecedented. The observed selectivity over non-polar CO2, polar volatile organic compounds (VOCs), and moisture has roots in competing electron sharing mechanisms at its different adsorption sites. This important result provides a significant reference to guide future MOFs related composite research to achieve the best sensing performance. On molecular adsorption, MWCNTs facilitate electrical transport via manipulating the ZIF-8 band gap to show a p-type semiconductor behavior with lower activation energy to induce a measurable resistance change. Excellent repeatability and reversibility are shown. Carbon-engineered MOFs composite has the potential to actuate similar selective response to low reactive gases via carrier manipulation in the energy bandgap.Item Open Access Sensitive and selective detection of adsorbed explosive molecules using opto-calorimetric infrared spectroscopy and micro-differential thermal analysis(ELSEVIER, 2016-03-15) Zandieh, Omid; Kim, SeonghwanMulti-modal explosive sensors based on microelectromechanical systems (MEMS) have been developed. Opto-calorimetric infrared (IR) spectroscopy, capable of obtaining molecular signatures of extremely small quantities of adsorbed explosive molecules, has been realized with the use of microheater/thermometer devices and a widely tunable quantum cascade laser. These devices respond to the heat generated by non-radiative decay process when the adsorbed explosive molecules are resonantly excited with IR light. Monitoring the variation in microthermometer signal as a function of illuminating IR wavelength corresponds to the conventional IR absorption spectrum of the adsorbed molecules. Moreover, the mass of the adsorbed molecules is determined by measuring the resonance frequency shift of the device for the quantitative analysis. In addition, micro-differential thermal analysis, which can be used to differentiate exothermic or endothermic reaction of heated molecules, has been performed with the same devices to provide additional orthogonal signal for trace explosive detection and sensor surface regeneration. We have demonstrated successful detection, differentiation, and quantification of trace amounts of explosive molecules (cyclotrimethylene trinitramine (RDX) and pentaerythritol tetranitrate (PETN)) and their mixtures using three orthogonal sensing signals.Item Open Access General Framework for Array Noise Analysis and Noise Performance of a Two-Element Interferometer With a Mutual-Coupling Canceler(IEEE, 2022-09) Belostotski, Leonid; Sutinjo, Adrian T.; Subrahmanyan, Ravi; Mandal, Soumyajit; Madanayake, ArjunaThis article investigates the noise performance of a two-element phased array and interferometer containing a recently introduced self-interference canceler, which in the context of this work acts as a mutual-coupling canceler. To this end, a general framework is proposed to permit noise analysis of this network and a large variety of other networks. The framework-based numerical analysis for a two-element-phased array shows that the addition of the canceler significantly increases the beam-equivalent noise temperature. For a two-element interferometer used in cosmology, this increase in noise temperature is still acceptable as the sky noise temperature in the 20-to-200 MHz band is high. When used in an interferometer, the canceler provides the ability to null mutual coherence at the interferometer output. The ability to provide matching to reduce the sensitivity of the null in mutual coherence to the phase of the 90∘ hybrids in the canceler is discussed.Item Open Access MOF/MWCNT−Nanocomposite Manipulates High Selectivity to Gas via Different Adsorption Sites with Varying Electron Affinity: A Study in Methane Detection in Parts-per-Billion(American Chemical Society, 2022-12-12) Homayoonnia, Setareh; Phani, Arindam; Kim, SeonghwanMetal−organic frameworks (MOFs) present specific adsorption sites with varying electron affinity which are uniquely conducive to selective gas sensing but are typically large-band-gap insulators. On the contrary, multiwall carbon nanotubes (MWCNTs) exhibit superior mesoscopic transport exploiting strong electron correlations among sub-bands below and above the Fermi level at room temperature. We synergize them in a new class of nanocomposites based on zeolitic imidazolate framework-8 (ZIF-8) and report selective sensing of CH4 in ∼10 parts-per-billion (ppb) with a determined limit of detection of ∼0.22 ppb, hitherto unprecedented. The observed selectivity to CH4 over non-polar CO2, polar volatile organic compounds, and moisture has roots in competing electron-sharing mechanisms at its different adsorption sites. This important result provides a significant reference to guide future MOF-related composite research to achieve the best sensing performance. On molecular adsorption, MWCNTs facilitate electrical transport via manipulating the ZIF-8 band gap to show a p-type semiconductor behavior with lower activation energy to induce a measurable resistance change. Excellent repeatability and reversibility are shown. A carbon-engineered MOF composite has the potential to actuate similar selective response to low reactive gases via carrier manipulation in the energy band gap.Item Open Access EEG Features to Quantify the NASA-TLX Factors of Cognitive Workload(IEEE Transactions on Human-Machine Systems, 2025) Zenia, Nusrat Z.; Tarng, Stanley; Ghaemi Dizaji, Lida; Hu, YaopingMeasuring cognitive workload (CWL) is crucial for dynamic task reallocation (i.e., adaptation) between a human and a machine in a human-machine system (HMS). A conventional measurement of the CWL is based on subjectively reported scores about the 6 factors of the NASA Task Load Index questionnaire. The questionnaire cannot however capture real-time fluctuations of the factors for an objective quantification. Additionally, each of the factors is associated with distinct activities and can be influenced by individual characteristics and/or task contexts. Such HMS adaptation should thus consider the objective quantification of each factor. So far, the quantification remains largely unexplored, while existing studies reveal a potential use of an electroencephalography (EEG) in measuring the CWL levels (e.g., high, medium, and low). Herein, we presented a pioneering study to propose EEG features for quantifying the factors. The pertinence of the features was demonstrated by their strong correlations with the scores of the factors across 3 distinct cases of visuomotor tasks. The pertinence is the steppingstone towards factor-based interventions in enabling HMS adaptation.Item Open Access Antenna Two-Port Electrical and Noise Parameters(IEEE, 2016-11) Groves, Patricia; Conroy, Philip; Belostotski, Leonid; Okoniewski, MichalNoise correlation matrices and noise parameters are useful for low-noise amplifier designers seeking to achieve the best noise performance out of their circuits. In some applications, such as radio astronomy, antennas and antenna arrays are part of receivers and, thus, modeling of the antenna noise is useful. Currently, antenna noise is modeled through antenna efficiency. A more accurate information on the highest-possible antenna efficiency is obtained from its S-parameters or noise parameters. In this letter, we show how the two-port S-parameters of an antenna can be determined by measuring its reflection coefficients inside two specifically sized Wheeler caps, in addition to a free-space measurement. We use the measurement to determine the noise correlation matrices and noise parameters of an antenna. The challenges of constructing appropriately sized Wheeler caps are discussed, and a new way of constructing a Wheeler cap is shown.Item Open Access A New 2nd–Order Allpass Filter in 130nm CMOS(IEEE, 2016-09) Ahmadi, Peyman; Maundy, Brent; Elwakil, A.S.; Belostotski, Leonid; Madanayake, ArjunaThis brief presents a novel wide-bandwidth second-order voltage-mode all-pass filter derived from a canonical single transistor bandpass filter. The core of the circuit consists of only one transistor, two resistors, and two energy storage elements. The operation of the proposed filter is validated experimentally. A filter implemented in an IBM 0.13-μm CMOS was measured to have a 55-ps group delay across a 6-GHz bandwidth while consuming 18.5 mW from a 1.5-V supply. This work experimentally demonstrates a CMOS all-pass filter that operates at multigigahertz frequencies and achieves the highest delay-bandwidth product compared to previously published CMOS all-pass filters known to the authors.Item Open Access A 2-D Signal Processing Model to Predict the Effect of Mutual Coupling on Array Factor(IEEE, 2013-09) Kota, John; Madanayake, Arjuna; Belostotski, Leonid; Wijenayake, Chamith; Bruton, Len T.A semi-analytical method for modeling the effects of electromagnetic mutual coupling in uniform linear array (ULA) of N antennas is proposed. The coupling is described as a two-dimensional (2-D) spatiotemporal transfer function derived from S-parameter measurements. The proposed 2-D transfer function enables prediction of the distortions in array factor due to coupling, and thereby enables the potential design of coupling-compensation algorithms. The method is verified with simulations in the 1.5-2.0-GHz range on both an N=7-element ULA using CST Microwave Studio using 50- Ω terminations and a N=3-element ULA in FEKO but with non-50 Ω impedance obtained from measurements of a CMOS low noise amplifier (LNA). Coupling effect on array factor of delay-sum-type beamformer was examined. The proposed model matches within an error of 4%-12% and 4%-10% with respect to the results from two full-wave electromagnetic simulators CST Microwave Studio and FEKO, respectively, in the frequency range 1.75-2 GHz.Item Open Access Use of GNSS Doppler for Prediction in Kalman Filtering for Smartphone Positioning(IEEE Journal of Indoor and Seamless Positioning and Navigation, 2023-11-28) Agarwal, Naman; O'Keefe, KyleThis article demonstrates an alternative approach that uses global navigation satellite system (GNSS) Doppler measurements in a Kalman filter (KF) to improve the accuracy of GNSS smartphone positioning. The proposed method automates the process of estimating the uncertainty of the dynamics model of the system, which is still a challenge for the conventional KF-based GNSS positioning methods that require heuristic tuning. Automation of dynamics model uncertainty estimation also demonstrates notable improvement in GNSS outlier detection or fault detection and exclusion. In addition, this article will perform a quality assessment of the GNSS observations obtained from two Android smartphones and investigate the performance of the proposed method when using GPS L1 + Galileo E1 signals compared to GPS L5 + Galileo E5a signals.Item Open Access Metal-Organic Framework Reinforced Highly Stretchable and Durable Conductive Hydrogel-Based Triboelectric Nanogenerator for Biomotion Sensing and Wearable Human-Machine Interfaces(Wiley, 2023-07-17) Rahman, Muhammad Toyabur; Rahman, Md Sazzadur; Kumar, Hitendra; Kim, Keekyoung; Kim, SeonghwanFlexible triboelectric nanogenerators (TENGs) with multifunctional sensing capabilities offer an elegant solution to address the growing energy supply challenges for wearable smart electronics. Herein, a highly stretchable and durable electrode for wearable TENG is developed using ZIF-8 as a reinforcing nanofiller in a hydrogel with LiCl electrolyte. ZIF-8 nanocrystals improve the hydrogel's mechanical properties by forming hydrogen bonds with copolymer chains, resulting in 2.7 times greater stretchability than pure hydrogel. The hydrogel electrode is encapsulated by microstructured silicone layers that act as triboelectric materials and prevent water loss from the hydrogel. Optimized ZIF-8-based hydrogel electrodes enhance the output performance of TENG through the dynamic balance of electric double layers (EDLs) during contact electrification. Thus, the as-fabricated TENG delivers an excellent power density of 3.47 Wm–2, which is 3.2 times higher than pure hydrogel-based TENG. The developed TENG can scavenge biomechanical energy even at subzero temperatures to power small electronics and serve as excellent self-powered pressure sensors for human-machine interfaces (HMIs). The nanocomposite hydrogel-based TENG can also function as a wearable biomotion sensor, detecting body movements with high sensitivity. This study demonstrates the significant potential of utilizing ZIF-8 reinforced hydrogel as an electrode for wearable TENGs in energy harvesting and sensor technology.Item Open Access In situ encapsulation of ZrQ in UiO-66 (Zr-BDC) for pore size control to enhance detection of a nerve agent simulant dimethyl methyl phosphonate (DMMP)(Wiley, 2022-06-08) Wong, Danny; Kim, Seonghwan; Abuzalat, OsamaChemical warfare agents are toxic chemicals that require rapid, easy-to-use, sensitive, and selective sensors to countermeasure. Simulants, such as dimethyl methyl phosphonate (DMMP), are used to test the effectiveness of sensors toward nerve agents. Metal organic frameworks (MOFs) offer large surface area and selective accessibility to active sites making them appealing for chemical sensing applications. In this work, we propose a fast, facile, direct synthesis method for manufacturing fluorescent MOFs with high sensitivity and selectivity. Zr-BDC is synthesized with 1, 4-benzenedicarboxylic acid (BDC) as an organic ligand and zirconium (Zr) metal. Fluorescent materials are then encapsulated in a novel and rapid in situ approach with strong solvents. X-ray diffraction, UV–visible spectroscopy, Fourier-transform infrared spectroscopy, and Raman spectroscopy are used to verify the successful formation of fluorescent MOFs. Compared to other methods, the gel synthesis method helps to control crystal growth leading to higher BET surface areas of ~1150 m2 g−1 for Zr-BDC and 850 m2 g−1 for ZrQ@Zr-BDC. Titration experiments show the sensitivity of the material to DMMP down to 8.3 nM with a highly linear response. Enhanced fluorescence and occupation of mesopores by ZrQ enable lower limit of detection than those of comparable works in literature. The encapsulation mechanism also prevents substantial defects that would otherwise lead to water adsorption.Item Embargo Object positional uncertainty modelling in 2D viewpoint planning(Elsevier--Automation in Construction, 2023)Item Open Access Advancing Smart Cities through Novel Social Media Text Analysis: A Case Study of Calgary(2023 IEEE Symposium Series on Computational Intelligence, 2023-09-15) Mitra Mirshafiee; Dr. Ann Barcomb; Dr. Benjamin TanIn numerous cities, population expansion and technological advancements necessitate proactive modernization and integration of technology. However, the existing bureaucratic structure often hinders local officials' efforts to effectively address and monitor residents' needs and enhance the city accordingly. Understanding what people find important and useful can be inferred from their posts on social media. Twitter, as one of the most popular social media platforms, provides us with valuable data that, with the right tools and analysis, can provide insights into the performance of urban services and residents' perception of them. In this study, we used the city of Calgary as an exemplar to gather tweets and analyze topics relating to city development, urban planning, and minorities. Natural language processing (NLP) techniques were used and developed to preprocess stored tweets, classify the emotions, and identify the topics present in the dataset to eventually provide a set of topics with the prevalent emotion in that topic. We utilized a variety of methods to analyze the collected data. BERTopic for topic modeling and few-shot learning using Setfit for emotion analysis outperformed the others. Hence, we identify issues related to city development, senior citizens, taxes, and unemployment using these methods, and we demonstrate how delving into these analyses can improve urban planning.Item Open Access Reflections on the 2023 Bonn UN Climate Change Conference: An Engineer's Perspective(2023-07-20) Demissie, Merkebe GetachewThe reflective process of the 2023 Bonn Climate Change Conference involves examining my initial expectations, reflecting on the conference experience, and identifying key takeaways that significantly impacted my professional development and understanding of climate change. This exercise aims to deepen my knowledge of global developments in climate change mitigation, adaptation, and financing. The conference serves as a powerful platform for raising awareness and promoting change. Additionally, I hope to inspire greater participation in the engineering community, leveraging this conference to increase public awareness about climate change and the vital role engineering plays in addressing these challenges.Item Open Access Direct simulation of stably stratified wall-bounded turbulence using the lattice Boltzmann method(2023-04-27) Guo, Junwei; Zhou, Qi; Wong, Ron Chik-KwongThe lattice Boltzmann method (LBM) is employed to simulate stratified plane Couette (SPC) flows in their statistically stationary turbulent state. The aim is to assess the suitability of the LBM for direct simulation of wall-bounded, sheared turbulence under the influence of stable stratification. The SPC flow is generated by two parallel plates moving in opposite directions with velocities ± U w, and the buoyancy is fixed at ± b w at the upper and lower plates, respectively. The Reynolds number Re = U w h / ν, where h is the half-gap height, and ν is the kinematic viscosity, varies from 1000 to 3000. The Richardson number Ri = b w h / U w 2 is set to 0 or 0.01. The LBM results are compared to direct numerical simulations using the conventional pseudo-spectral method, and good agreement is found in various turbulence statistics, such as mean and fluctuation velocity and buoyancy, Reynolds stress, turbulent heat flux, dissipation rate, wall fluxes of momentum and heat, and longitudinal and transverse turbulence spectra. The results from grid-sensitivity tests indicate that the uniform isotropic grid spacing Δ x in LBM needs to be no greater than approximately the near-wall viscous length scale δ ν to achieve adequate resolution of stratified wall-bounded turbulence.Item Open Access Extended-FEM analysis of injection-induced slip on a fault with rate-and-state friction: Insights into parameters that control induced seismicity(Springer, 2023-03-09) Hosseini, Navid; Priest, Jeffrey; Eaton, DavidThe extended finite element method (X-FEM) is utilised to simulate the behavior of a heterogeneous fault characterized by rate-state frictional rheology, embedded within a poroelastic medium. The displacement and pore-pressure fields that are discontinuous across the fault are computed using X-FEM, by enriching the standard finite element approximation with additional degrees of freedom for elements intersected by the fault. We investigate a Mw 4.1 injection-induced earthquake in western Canada; this model incorporates depth-varying rate-slip behavior wherein a high-pressure zone due to hydraulic fracturing stimulation intersects the fault within a stable layer, producing aseismic slip that progressively loads an unstable fault region, thereby triggering dynamic rupture. Parametric studies using our numerical approach provide insights into the influence of rate-state parameters on fault activation, as well as hydraulic properties of a damage zone that surrounds the fault. Results confirm that aseismic slip near the injection zone propagates outwards to seismogenic unstable regions of the fault. The coseismic slip profile, seismic moment, and slip latency are determined by the difference a − b for rate-state parameters of the unstable fault regions. Hydraulic diffusivity in the damage zone controls the rate of pore-pressure diffusion along the fault, which affects timing of the initial seismic event and aftershock productivity.
