Open Access Publications
Permanent URI for this collection
Open access publications by faculty, postdocs, and graduate students in the Department of Electrical and Computer Engineering
Browse
Browsing Open Access Publications by Issue Date
Now showing 1 - 20 of 105
Results Per Page
Sort Options
Item Contactless electroreflectance study of E0 and E0+ΔSO transitions in In0.53Ga0.47BiXAs1-X alloys(American Institute of Physics, 2011) Kudrawiec, R.; Kopaczek, J.; Misiewicz, J.; Petropoulos, J. P.; Zhong, Y.; Zide, J. M. O.; R. Kudrawiec, J. Kopaczek, J. Misiewicz, J. P. Petropoulos, Y. Zhong, and J. M. O. Zide; Petropoulos, J. P.; Zhong, Y.; Zide, J. M. O. (orcid.org/0000-0002-6378-7221)Energies of E0 and E0 + ΔSO transitions in In0.53Ga0.47BixAs1−x alloys with 0 < x ≤ 0.036 have been studied by contactless electroreflectance spectroscopy at room temperature. It has been clearly observed that the E0 transition shifts to longer wavelengths (∼50 meV/% of Bi), while the E0 + ΔSO transition is approximately unchanged with changes in Bi concentration. These changes in the energies of optical transitions are discussed in the context of the valence band anticrossing model as well as the common anion rule applied to III-V semiconductors.Item Optical and electrical characterization of InGaBiAs for use as a new mid-infrared optoelectronic material(American Institute of Physics, 2011) Petropoulos, J. P.; Zhong, Y.; Zide, J. M. O.; Petropoulos, J. P., Zhong, Y., Zide, J. M. O.; Petropoulos, J. P.; Zhong, Y.; Zide, J. M. O. (orcid.org/0000-0002-6378-7221)In0.53Ga0.47BixAs1 x films were grown on InP:Fe substrates by molecular beam epitaxy, with Bi concentrations up to x¼3.60%. Bi content in the epilayers was determined by Rutherford backscattering spectroscopy, and channeling measurements show Bi incorporating substitutionally. Unlike previous work, electrical and optical data are obtained for all samples. A redshift in peak wavelength of about 56 meV/%Bi was observed using spectrophotometry. The valence band anti-crossing model is applied, showing InyGa1 yBixAs1 x lattice-matched to InP is possible by varying the composition, with a theoretical cutoff wavelength of about 6 lm.Item Effects of molecular beam epitaxial growth conditions on composition and optical properties of InGaBiAs(American Institute of Physics, 2012) Zhong, Y.; Dongmo, P. B.; Petropoulos, J. P.; Zide, J. M. O.; Y. Zhong, P. B. Dongmo, J. P. Petropoulos, and J. M. O. Zide; Zhong, Y.; Dongmo, P. B.; Petropoulos, J. P.; Zide, J. M. O.(orcid.org/0000-0002-6378-7221)We describe the growth conditions of InxGa1 xBiyAs1 y (lattice-mismatched and matched) on InP substrates by molecular beam epitaxy and the resulting properties. Due to their anomalously narrow bandgaps and the presence of bismuth, these materials are promising for optoelectronics and thermoelectrics. Low growth temperature and moderate As/Bi beam equivalent pressure ratios are beneficial for Bi incorporation, in good qualitative agreement with GaBiyAs1 y on GaAs. Up to 6.75% bismuth is incorporated. High resolution x-ray diffraction and reciprocal space mapping show that InxGa1 xBiyAs1 y samples exhibit good crystalline quality and zero relaxation. The band gap is reduced in agreement with theoretical predictions. Lattice-matched samples have been produced with lattice mismatch 0.21%.Item Physical Analysis of VO2 Films Grown by Atomic Layer Deposition and RF Magnetron Sputtering(The Electrochemical Society, 2014-04-30) Tangirala, Madhavi; Zhang, Kai; Nminibapiel, David; Pallem, Venkateswara; Dussarrat, Christian; Cao, Wei; Adam, Thomas N.; Johnson, Corbet S.; Elsayed-Ali, Hani E.; Baumgart, Helmut; Madhavi Tangirala, Kai Zhang, David Nminibapiel, Venkateswara Pallem, Christian Dussarrat, Wei Cao, Thomas N. Adam, Corbet S. Johnson, Hani E. Elsayed-Ali and Helmut Baumgarta; Zhang, KaiAmong the many vanadium suboxides and different stoichiometries, VO2 has received considerable attention due to its remarkable metal-insulator transition (MIT) behavior, which causes a significant reversible change in its electrical and optical properties occurring across the phase transition at 67◦C. The initially amorphous VO2 thin films were fabricated by the emerging, Atomic Layer Deposition (ALD) technique with (tetrakis[ethylmethylamino]vanadium) {V(NEtMe)4} as precursor and H2O vapor as oxidation agent. For benchmarking we have also used the RF Magnetron Sputtering technique to deposit metallic vanadium thin films, which were later oxidized during furnace annealing. Post annealing of the as-deposited ALD films was performed in order to obtain the technologically important form of crystallized VO2 thin films using furnace annealing. All film depositions were carried out on native oxide covered (100) Si substrates. The conditions for successful furnace annealing are reported in terms of temperature and annealing gas composition and the physical characterization results are presented.Item Experiences with non-intrusive monitoring of distribution transformers based on the on-line frequency response(Universidad Nacional de Colombia, 2015-02-13) Gomez-Luna, Eduardo; Duarte Guardon, Cesar Antonio; Aponte, Guillermo; Pleite Guerra, Jorge; Goossen, Keith W.; E. Gomez-Luna, C. Duart2, G. Aponte, J. Pleite and K. W. Goossen; Duarte Guardon, Cesar AntonioThe following article presents the results obtained in experiences that use the Impulse Frequency Response Analysis (IFRA) method with a transformer in service. The IFRA method has been implemented in order to transform the transient signals to the frequency domain using Discrete Fourier Transform (DFT). However, it can be considered that the DFT is not the most suitable tool for this type of analysis, since, by definition, this tool is useful for processing stationary signals. Taking that into consideration, the analysis of transient signals could be hypothetically improved by using continuous wavelet transform (CWT), given their variable time/frequency resolution. The analysis of transient signals in Wavelet domain has improved the repeatability of the frequency response curves, as it has been ob-served in experimental results. The proposed on-line IFRA method, based on Wavelet transform, was validated under load and no-load conditions on a 150 kVA three-phase transformer 13200/225 Volts, in the Campus of the Universidad del Valle, Cali, Colombia.Item Impact of Different Surface Ligands on the Optical Properties of PbS Quantum Dot Solids(MDPI (Multidisciplinary Digital Publishing Institute), 2015-04-21) Xu, Fan; Gerlein, Luis Felipe; Ma, Xin; Haughn, Chelsea R.; Doty, Matthew F.; Cloutier, Sylvain G.; Fan Xu, Luis Felipe Gerlein, Xin Ma, Chelsea R. Haughn, Matthew F. Doty and Sylvain G. Cloutier; Xu, Fan; Ma, Xin; Doty, Matthew F.; Cloutier, Sylvain G.The engineering of quantum dot solids with low defect concentrations and efficient carrier transport through a ligand strategy is crucial to achieve efficient quantum dot (QD) optoelectronic devices. Here, we study the consequences of various surface ligand treatments on the light emission properties of PbS quantum dot films using 1,3-benzenedithiol (1,3-BDT), 1,2-ethanedithiol (EDT), mercaptocarboxylic acids (MPA) and ammonium sulfide ((NH4)2S). We first investigate the influence of different ligand treatments on the inter-dot separation, which mainly determines the conductivity of the QD films. Then, through a combination of photoluminescence and transient photoluminescence characterization, we demonstrate that the radiative and non-radiative recombination mechanisms in the quantum dot films depend critically on the length and chemical structure of the surface ligands.Item Impact of Different Surface Ligands on the Optical Properties of PbS Quantum Dot Solids(MDPI AG, 2015-04-21) Xu, Fan; Gerlein, Luis Felipe; Ma, Xin; Haughn, Chelsea R.; Doty, Matthew F.; Cloutier, Sylvain G.; Fan Xu, Luis Felipe Gerlein, Xin Ma, Chelsea R. Haughn, Matthew F. Doty and Sylvain G. Cloutier; Xu, Fan; Ma, Xin; Haughn, Chelsea R.; Doty, Matthew F.; Cloutier, Sylvain G.The engineering of quantum dot solids with low defect concentrations and efficient carrier transport through a ligand strategy is crucial to achieve efficient quantum dot (QD) optoelectronic devices. Here, we study the consequences of various surface ligand treatments on the light emission properties of PbS quantum dot films using 1,3-benzenedithiol (1,3-BDT), 1,2-ethanedithiol (EDT), mercaptocarboxylic acids (MPA) and ammonium sulfide ((NH4)2S). We first investigate the influence of different ligand treatments on the inter-dot separation, which mainly determines the conductivity of the QD films. Then, through a combination of photoluminescence and transient photoluminescence characterization, we demonstrate that the radiative and non-radiative recombination mechanisms in the quantum dot films depend critically on the length and chemical structure of the surface ligands.Item Multi-spectral compressive snapshot imaging using RGB image sensors(The Optical Society of America, 2015-04-30) Rueda, Hoover; Lau, Daniel; Arce, Gonzalo R.; Hoover Rueda, Daniel Lau, and Gonzalo R. Arce; Rueda, Hoover; Arce, Gonzalo R.Compressive sensing is a powerful sensing and reconstruction framework for recovering high dimensional signals with only a handful of observations and for spectral imaging, compressive sensing offers a novel method of multispectral imaging. Specifically, the coded aperture snapshot spectral imager (CASSI) system has been demonstrated to produce multi-spectral data cubes color images from a single snapshot taken by a monochrome image sensor. In this paper, we expand the theoretical framework of CASSI to include the spectral sensitivity of the image sensor pixels to account for color and then investigate the impact on image quality using either a traditional color image sensor that spatially multiplexes red, green, and blue light filters or a novel Foveon image sensor which stacks red, green, and blue pixels on top of one another.Item Full-physics 3-D heterogeneous simulations of electromagnetic induction fields on level and deformed sea ice(International Glaciological Society, 2015-10-01) Samluk, Jesse P.; Geiger, Cathleen A.; Weiss, Chester J.; Jesse P. SAMLUK, Cathleen A. GEIGER, Chester J. WEISS; Samluk, Jesse P.; Geiger, Cathleen A.In this paper we explore simulated responses of electromagnetic (EM) signals relative to in situ field surveys and quantify the effects that different values of conductivity in sea ice have on the EM fields. We compute EM responses of ice types with a three-dimensional (3-D) finite-volume discretization of Maxwell’s equations and present 2-D sliced visualizations of their associated EM fields at discrete frequencies. Several interesting observations result: First, since the simulator computes the fields everywhere, each gridcell acts as a receiver within the model volume, and captures the complete, coupled interactions between air, snow, sea ice and sea water as a function of their conductivity; second, visualizations demonstrate how 1-D approximations near deformed ice features are violated. But the most important new finding is that changes in conductivity affect EM field response by modifying the magnitude and spatial patterns (i.e. footprint size and shape) of current density and magnetic fields. These effects are demonstrated through a visual feature we define as ‘null lines’. Null line shape is affected by changes in conductivity near material boundaries as well as transmitter location. Our results encourage the use of null lines as a planning tool for better ground-truth field measurements near deformed ice types.Item On the uncertainty of sea-ice isostasy(International Glaciological Society, 2015-10-01) Geiger, Cathleen A.; Wadhams, Peter; Müller, Hans-Reinhard; Richter-Menge, Jacqueline A.; Samluk, Jesse P.; DeLiberty, Tracy L.; Corradina, Victoria; Cathleen GEIGER, Peter WADHAMS, Hans-Reinhard MÜLLER, Jacqueline RICHTER-MENGE, Jesse SAMLUK, Tracy DELIBERTY, Victoria CORRADINA1; Geiger, Cathleen A.; DeLiberty, Tracy L.; Corradina, Victoria; Samluk, Jesse P.During late winter 2007, coincident measurements of sea ice were collected using various sensors at an ice camp in the Beaufort Sea, Canadian Arctic. Analysis of the archived data provides new insight into sea-ice isostasy and its related R-factor through case studies at three scales using different combinations of snow and ice thickness components. At the smallest scale (<1 m; point scale), isostasy is not expected, so we calculate a residual and define this as ��� (‘zjey’) to describe vertical displacement due to deformation. From 1 to 10m length scales, we explore traditional isostasy and identify a specific sequence of thickness calculations which minimize freeboard and elevation uncertainty. An effective solution exists when the R-factor is allowed to vary: ranging from 2 to 12, with mean of 5.17, mode of 5.88 and skewed distribution. At regional scales, underwater, airborne and spaceborne platforms are always missing thickness variables from either above or below sea level. For such situations, realistic agreement is found by applying small-scale skewed ranges for the R-factor. These findings encourage a broader isostasy solution as a function of potential energy and length scale. Overall, results add insight to data collection strategies and metadata characteristics of different thickness products.Item Impact of spatial aliasing on sea-ice thickness measurements(International Glaciological Society, 2015-10-01) Geiger, Cathleen A.; Müller, Hans-Reinhard; Samluk, Jesse P.; Bernstein, E. Rachel; Richter-Menge, Jacqueline A.; Cathleen GEIGER, Hans-Reinhard MÜLLER, Jesse P. SAMLUK, E. Rachel BERNSTEIN, Jacqueline RICHTER-MENGE; Geiger, Cathleen A.; Samluk, Jesse P.; Bernstein, E. RachelWe explore spatial aliasing of non-Gaussian distributions of sea-ice thickness. Using a heuristic model and >1000 measurements, we show how different instrument footprint sizes and shapes can cluster thickness distributions into artificial modes, thereby distorting frequency distribution, making it difficult to compare and communicate information across spatial scales. This problem has not been dealt with systematically in sea ice until now, largely because it appears to incur no significant change in integrated thickness which often serves as a volume proxy. Concomitantly, demands are increasing for thickness distribution as a resource for modeling, monitoring and forecasting air–sea fluxes and growing human infrastructure needs in a changing polar environment. New demands include the characterization of uncertainties both regionally and seasonally for spaceborne, airborne, in situ and underwater measurements. To serve these growing needs, we quantify the impact of spatial aliasing by computing resolution error (Er) over a range of horizontal scales (x) from 5 to 500 m. Results are summarized through a power law (Er = bxm) with distinct exponents (m) from 0.3 to 0.5 using example mathematical functions including Gaussian, inverse linear and running mean filters. Recommendations and visualizations are provided to encourage discussion, new data acquisitions, analysis methods and metadata formats.Item Road-Aided Ground Slowly Moving Target 2D Motion Estimation for Single-Channel Synthetic Aperture Radar(MDPI Ag, 2016-01-31) Wang,Zhirui; Xu,Jia; Huang,Zuzhen; Zhang,Xudong; Xia,Xiang-Gen; Long,Teng; Bao,Qian; Zhirui Wang, Jia Xu, Zuzhen Huang , Xudong Zhang, Xiang-Gen Xia, Teng Long and Qian Bao; Xia, Xiang-GenTo detect and estimate ground slowly moving targets in airborne single-channel synthetic aperture radar (SAR), a road-aided ground moving target indication (GMTI) algorithm is proposed in this paper. First, the road area is extracted from a focused SAR image based on radar vision. Second, after stationary clutter suppression in the range-Doppler domain, a moving target is detected and located in the image domain via the watershed method. The target's position on the road as well as its radial velocity can be determined according to the target's offset distance and traffic rules. Furthermore, the target's azimuth velocity is estimated based on the road slope obtained via polynomial fitting. Compared with the traditional algorithms, the proposed method can effectively cope with slowly moving targets partly submerged in a stationary clutter spectrum. In addition, the proposed method can be easily extended to a multi-channel system to further improve the performance of clutter suppression and motion estimation. Finally, the results of numerical experiments are provided to demonstrate the effectiveness of the proposed algorithm.Item Beamforming Based Full-Duplex for Millimeter-Wave Communication(MDPI AG, 2016-07-21) Liu,Xiao; Xiao,Zhenyu; Bai,Lin; Choi,Jinho; Xia,Pengfei; Xia,Xiang-Gen; Xiao Liu, Zhenyu Xiao, Lin Bai, Jinho Choi, Pengfei Xia, Xiang-Gen Xia; Xia, Xiang-GenIn this paper, we study beamforming based full-duplex (FD) systems in millimeter-wave (mmWave) communications. A joint transmission and reception (Tx/Rx) beamforming problem is formulated to maximize the achievable rate by mitigating self-interference (SI). Since the optimal solution is difficult to find due to the non-convexity of the objective function, suboptimal schemes are proposed in this paper. A low-complexity algorithm, which iteratively maximizes signal power while suppressing SI, is proposed and its convergence is proven. Moreover, two closed-form solutions, which do not require iterations, are also derived under minimum-mean-square-error (MMSE), zero-forcing (ZF), and maximum-ratio transmission (MRT) criteria. Performance evaluations show that the proposed iterative scheme converges fast (within only two iterations on average) and approaches an upper-bound performance, while the two closed-form solutions also achieve appealing performances, although there are noticeable differences from the upper bound depending on channel conditions. Interestingly, these three schemes show different robustness against the geometry of Tx/Rx antenna arrays and channel estimation errors.Item A mechanistic stochastic framework for regulating bacterial cell division(Nature Publishing Group, 2016-07-26) Ghusinga,Khem Raj; Vargas-Garcia,Cesar A.; Singh,Abhyudai; Khem Raj Ghusinga, Cesar A. Vargas-Garcia,Abhyudai Singh; Singh, AbhyudaiHow exponentially growing cells maintain size homeostasis is an important fundamental problem. Recent single-cell studies in prokaryotes have uncovered the adder principle, where cells add a fixed size (volume) from birth to division, irrespective of their size at birth. To mechanistically explain the adder principle, we consider a timekeeper protein that begins to get stochastically expressed after cell birth at a rate proportional to the volume. Cell-division time is formulated as the first-passage time for protein copy numbers to hit a fixed threshold. Consistent with data, the model predicts that the noise in division timing increases with size at birth. Intriguingly, our results show that the distribution of the volume added between successive cell-division events is independent of the newborn cell size. This was dramatically seen in experimental studies, where histograms of the added volume corresponding to different newborn sizes collapsed on top of each other. The model provides further insights consistent with experimental observations: the distribution of the added volume when scaled by its mean becomes invariant of the growth rate. In summary, our simple yet elegant model explains key experimental findings and suggests a mechanism for regulating both the mean and fluctuations in cell-division timing for controlling size.Item Transcriptional Bursting Explains the Noise-Versus-Mean Relationship in mRNA and Protein Levels(Public Library Science, 2016-07-28) Dar,Roy D.; Shaffer,Sydney M.; Singh,Abhyudai; Razooky,Brandon S.; Simpson,Michael L.; Raj,Arjun; Weinberger,Leor S.; Roy D. Dar, Sydney M. Shaffer, Abhyudai Singh, Brandon S. Razooky, Michael L. Simpson, Arjun Raj, Leor S. Weinberger; Singh, AbhyudaiRecent analysis demonstrates that the HIV-1 Long Terminal Repeat (HIV LTR) promoter exhibits a range of possible transcriptional burst sizes and frequencies for any mean-expression level. However, these results have also been interpreted as demonstrating that cell-tocell expression variability (noise) and mean are uncorrelated, a significant Developmentiation from previous results. Here, we re-examine the available mRNA and protein abundance data for the HIV LTR and find that noise in mRNA and protein expression scales inversely with the mean along analytically predicted transcriptional burst-sizemanifolds. We then experimentally perturb transcriptional activity to test a prediction of the multiple burst-size model: that increasing burst frequency will cause mRNA noise to decrease along given burst-size lines as mRNA levels increase. The data show that mRNA and protein noise decrease as mean expression increases, supporting the canonical inverse correlation between noise and mean.Item Intercellular Variability in Protein Levels from Stochastic Expression and Noisy Cell Cycle Processes(Public Library Science, 2016-08-18) Soltani,Mohammad; Vargas-Garcia,Cesar A.; Antunes,Duarte; Singh,Abhyudai; Mohammad Soltani, Cesar A. Vargas-Garcia, Duarte Antunes, Abhyudai Singh; Singh, AbhyudaiInside individual cells, expression of genes is inherently stochastic and manifests as cell-to-cell variability or noise in protein copy numbers. Since proteins half-lives can be comparable to the cell-cycle length, randomness in cell-division times generates additional intercellular variability in protein levels. Moreover, as many mRNA/protein species are expressed at low-copy numbers, errors incurred in partitioning of molecules between two daughter cells are significant. We derive analytical formulas for the total noise in protein levels when the cell-cycle duration follows a general class of probability distributions. Using a novel hybrid approach the total noise is decomposed into components arising from i) stochastic expression; ii) partitioning errors at the time of cell division and iii) random cell-division events. These formulas reveal that random cell-division times not only generate additional extrinsic noise, but also critically affect the mean protein copy numbers and intrinsic noise components. Counter intuitively, in some parameter regimes, noise in protein levels can decrease as cell-division times become more stochastic. Computations are extended to consider genome duplication, where transcription rate is increased at a random point in the cell cycle. We systematically investigate how the timing of genome duplication influences different protein noise components. Intriguingly, results show that noise contribution from stochastic expression is minimized at an optimal genome-duplication time. Our theoretical results motivate new experimental methods for decomposing protein noise levels from synchronized and asynchronized single-cell expression data. Characterizing the contributions of individual noise mechanisms will lead to precise estimates of gene expression parameters and techniques for altering stochasticity to change phenotype of individual cells.Item Effect of Al2O3 Buffer Layers on the Properties of Sputtered VO2 Thin Films(Springer Berlin Heidelberg, 2017-02-14) Zhang, Dainan; Wen, Tianlong; Xiong, Ying; Qiu, Donghong; Wen, Qiye; Dainan Zhang, Tianlong Wen, Ying Xiong, Donghong Qiu, Qiye Wen; Zhang, DainanVO2 thin films were grown on silicon substrates using Al2O3 thin films as the buffer layers. Compared with direct deposition on silicon, VO2 thin films deposited on Al2O3 buffer layers experience a significant improvement in their microstructures and physical properties. By optimizing the growth conditions, the resistance of VO2 thin films can change by four orders of magnitude with a reduced thermal hysteresis of 4 C at the phase transition temperature. The electrically driven phase transformation was measured in Pt/Si/Al2O3/VO2/Au heterostructures. The introduction of a buffer layer reduces the leakage current and Joule heating during electrically driven phase transitions. The C–V measurement result indicates that the phase transformation of VO2 thin films can be induced by an electrical field.Item Memristors Based on (Zr, Hf, Nb, Ta, Mo, W) High-Entropy Oxides(Advanced Electronic Materials, 2021-04-15) Ahn, Minhyung; Park, Yongmo; Lee, Seung Hwan; Chae, Sieun; Lee, Jihang; Heron, John T.; Kioupakis, Emmanouil; Lu, Wei D.; Phillips, Jamie D.Memristors have emerged as transformative devices to enable neuromorphic and in-memory computing, where success requires the identification and development of materials that can overcome challenges in retention and device variability. Here, high-entropy oxide composed of Zr, Hf, Nb, Ta, Mo, and W oxides is first demonstrated as a switching material for valence change memory. This multielement oxide material provides uniform distribution and higher concentration of oxygen vacancies, limiting the stochastic behavior in resistive switching. (Zr, Hf, Nb, Ta, Mo, W) high-entropy-oxide-based memristors manifest the “cocktail effect,” exhibiting comparable retention with HfO2- or Ta2O5-based memristors while also demonstrating the gradual conductance modulation observed in WO3-based memristors. The electrical characterization of these high-entropy-oxide-based memristors demonstrates forming-free operation, low device and cycle variability, gradual conductance modulation, 6-bit operation, and long retention which are promising for neuromorphic applications.Item AI Cannot Understand Memes: Experiments with OCR and Facial Emotions(Computers, Materials & Continua, 2021-05-11) Priyadarshini, Ishaani; Cotton, ChaseThe increasing capabilities of Artificial Intelligence (AI), has led researchers and visionaries to think in the direction of machines outperforming humans by gaining intelligence equal to or greater than humans, which may not always have a positive impact on the society. AI gone rogue, and Technological Singularity are major concerns in academia as well as the industry. It is necessary to identify the limitations of machines and analyze their incompetence, which could draw a line between human and machine intelligence. Internet memes are an amalgam of pictures, videos, underlying messages, ideas, sentiments, humor, and experiences, hence the way an internet meme is perceived by a human may not be entirely how a machine comprehends it. In this paper, we present experimental evidence on how comprehending Internet Memes is a challenge for AI. We use a combination of Optical Character Recognition techniques like Tesseract, Pixel Link, and East Detector to extract text from the memes, and machine learning algorithms like Convolutional Neural Networks (CNN), Region-based Convolutional Neural Networks (RCNN), and Transfer Learning with pre-trained denseNet for assessing the textual and facial emotions combined. We evaluate the performance using Sensitivity and Specificity. Our results show that comprehending memes is indeed a challenging task, and hence a major limitation of AI. This research would be of utmost interest to researchers working in the areas of Artificial General Intelligence and Technological Singularity.Item Modeling protein concentrations in cycling cells using stochastic hybrid systems(IFAC-PapersOnLine, 2021-07-16) Vahdat, Zahra; Xu, Zikai; Singh, AbhyudaiWe analyze a class of time-triggered stochastic hybrid systems where the state-space evolves as per a linear time-invariant dynamical system. This continuous-time evolution is interspersed with two kinds of stochastic resets. The first reset occurs based on an internal timer that measures the time elapsed since it last occurred. Whenever the first reset occurs, the states-space undergoes a random jump, and the timer is reset to zero. The second reset occurs based on an arbitrary timer-depended rate, and whenever this reset fires, the state-space is changed based on a given random map. We provide exact conditions for this class of systems that lead to finite statistical moments and the corresponding exact analytical expressions for the first two moments. This framework is applied to study random fluctuations in the concentration of a protein in a growing cell. In the context of this example, the timer denotes the time elapsed since the cell was born, and the cell division event (first reset) is triggered based on a timer-dependent rate. The second reset corresponds to the protein synthesis in stochastic bursts, and finally, during cell growth, protein concentration continuously decreases due to dilution. Our analysis provides closed-form formulas for the noise in the protein concentration and leads to a striking result - for a constant (timer-independent) protein synthesis rate, the noise in the protein concentration is invariant of the noise in the cell-cycle time. Finally, we provide a rigorous framework for investigating protein noise levels for different forms of timer-dependent synthesis rates, as is the case for cell-cycle regulated genes inside the cell.