1,618 research outputs found

    2023-2024 Catalog

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    The 2023-2024 Governors State University Undergraduate and Graduate Catalog is a comprehensive listing of current information regarding:Degree RequirementsCourse OfferingsUndergraduate and Graduate Rules and Regulation

    ENHANCING THE OPERATIONAL RESILIENCE OF CYBER- MANUFACTURING SYSTEMS (CMS) AGAINST CYBER-ATTACKS

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    Cyber-manufacturing systems (CMS) are interconnected production environments comprised of complex and networked cyber-physical systems (CPS) that can be instantiated across one or many locations. However, this vision of manufacturing environments ushers in the challenge of addressing new security threats to production systems that still contain traditional closed legacy elements. The widespread adoption of CMS has come with a dramatic increase in successful cyber-attacks. With a myriad of new targets and vulnerabilities, hackers have been able to cause significant economic losses by disrupting manufacturing operations, reducing outgoing product quality, and altering product designs. This research aims to contribute to the design of more resilient cyber-manufacturing systems. Traditional cybersecurity mechanisms focus on preventing the occurrence of cyber-attacks, improving the accuracy of detection, and increasing the speed of recovery. More often neglected is addressing how to respond to a successful attack during the time from the attack onset until the system recovery. We propose a novel approach that correlates the state of production and the timing of the attack to predict the effect on the manufacturing key performance indicators. Then a real-time decision strategy is deployed to select the appropriate response to maintain availability, utilization efficiency, and a quality ratio above degradation thresholds until recovery. Our goal is to demonstrate that the operational resilience of CMS can be enhanced such that the system will be able to withstand the advent of cyber-attacks while remaining operationally resilient. This research presents a novel framework to enhance the operational resilience of cyber-manufacturing systems against cyber-attacks. In contrast to other CPS where the general goal of operational resilience is to maintain a certain target level of availability, we propose a manufacturing-centric approach in which we utilize production key performance indicators as targets. This way we adopt a decision-making process for security in a way that is aligned with the operational strategy and bound to the socio-economic constraints inherent to manufacturing. Our proposed framework consists of four steps: 1) Identify: map CMS production goals, vulnerabilities, and resilience-enhancing mechanisms; 2) Establish: set targets of performance in production output, scrap rate, and downtime at different states; 3) Select: determine which mechanisms are needed and their triggering strategy, and 4) Deploy: integrate into the operation of the CMS the selected mechanisms, threat severity evaluation, and activation strategy. Lastly, we demonstrate via experimentation on a CMS testbed that this framework can effectively enhance the operational resilience of a CMS against a known cyber-attack

    30th European Congress on Obesity (ECO 2023)

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    This is the abstract book of 30th European Congress on Obesity (ECO 2023

    Santé cardiométabolique, paramètres inflammatoires et faisabilité d’une intervention nutritionnelle en oncologie pédiatrique

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    Grâce aux progrès médicaux, le taux de survie à 5 ans des enfants et des adolescents diagnostiqués d’un cancer est maintenant d’environ 85%. Malgré ces chiffres encourageants, à l’âge adulte, les survivants d’un cancer pédiatrique sont à risque de développer plusieurs problèmes de santé dont des maladies cardiovasculaires et des complications cardiométaboliques (CM) comme de l'hypertension, une résistance à l'insuline, de la dyslipidémie et de l'obésité abdominale. Devant cette réalité, il importe d’enrichir les connaissances quant à l’évolution et l’étiologie de ces séquelles tôt dans la trajectoire du cancer et de la survivance afin d’améliorer la prise en charge précoce des patients. Pourtant, à ce jour, seulement quelques études ont décrit la santé CM de patients à court terme après la fin des traitements et les facteurs associés au développement hâtif de ces complications demeurent méconnus. Le cancer et ses traitements causent un état pro-inflammatoire & pro-oxydant susceptible d’entraîner le développement de complications CM. En parallèle, la période de traitement est caractérisée par des changements dans les habitudes alimentaires, un comportement sédentaire et une augmentation de l’indice de masse corporelle (IMC), qui peuvent persister après la fin des traitements. À long terme chez les survivants de cancers pédiatriques, le statut d’obésité à la fin des traitements ainsi que certains biomarqueurs inflammatoires ont été associés à la présence de complications CM. De plus, la composition des HDL est différente à long terme chez les survivants de la leucémie lymphoblastique aiguë comparativement à celle de contrôles sains. Étant donné l’importance de tous ces facteurs, il est primordial de les décrire à court terme, après la fin des traitements. Par ailleurs, l’obésité au moment du diagnostic et l’augmentation de l’IMC pendant le traitement influencent négativement le pronostic et l’occurrence d’effets secondaires graves durant les traitements. Toutefois, la plupart des interventions nutritionnelles en oncologie pédiatrique ne tiennent pas en compte la problématique du gain de poids significatif durant les traitements. Ainsi, il semble important d’évaluer la possibilité d’implanter des stratégies misant sur la promotion d'habitudes de vie saines tôt après le diagnostic d’un cancer pédiatrique afin d’améliorer l'état nutritionnel, la qualité de vie et possiblement la santé CM des patients à court et à long terme. Les travaux de cette thèse ont pour but de : i) décrire la santé CM de patients en oncologie pédiatrique peu de temps après les traitements, ii) élaborer, par une revue de littérature, sur le rôle de l’état inflammatoire et oxydant relié au cancer de l’enfant et ses traitements dans le développement des complications CM, iii) évaluer les associations entre l’évolution de l’IMC durant la trajectoire de soins d’un cancer pédiatrique et les complications CM ainsi que le statut inflammatoire; vi) détailler la composition lipidique et protéique des HDL des patients peu de temps après la fin des traitements du cancer pédiatrique et; v) déterminer la faisabilité d’une intervention nutritionnelle précoce chez des enfants et des adolescents nouvellement diagnostiqués d’un cancer. Pour ce faire, deux cohortes de patients ont été recrutées dans le cadre de l’étude VIE (Valorisation, Implication, Éducation) au CHU Sainte-Justine. D’abord, 80 patients suivis en hémato-oncologie ont été rencontrés en moyenne 1,4 ± 0,8 an après la fin de leur traitement contre un cancer pédiatrique. De ce groupe, 56,3 % étaient des filles, 43,8% avaient été traités pour une leucémie. L'âge moyen lors de la rencontre était de 11,8 ans (min - max: 4,5 - 21,0). La proportion de complications CM observée était de 26,3 % pour la pression artérielle (PA) élevée, 8,1 % pour le prédiabète, 35,0 % pour la dyslipidémie et 11,5 % pour l’obésité. Les adolescents (≥ 10 ans au diagnostic) étaient plus susceptibles d'avoir une PA élevée, une dyslipidémie et de cumuler ≥ 2 complications CM que les enfants. Être en surpoids ou obèse après le traitement était associé à des niveaux plus élevés d'insuline, d’HOMA-IR, de leptine et du ratio leptine/adiponectine du plasma. Chez les patients en surpoids ou obèses à la fin du traitement, le changement de l’IMC a été relié au niveau d’adipokines (leptine et ratio leptine/adiponectine) après les traitements. De plus, les fractions de HDL3 étaient enrichies en triglycérides chez les patients présentant une dyslipidémie à l’évaluation par rapport aux normolipidiques et chez ceux ayant été traités avec des doses de doxorubicine ≥ 90 mg/m2 par rapport à des doses inférieures. Parallèlement, une intervention nutritionnelle d'un an, comprenant une évaluation initiale et six visites de suivi tous les deux mois, a été effectuée auprès de 61 participants. De ceux-ci, 51,6% étaient des garçons, l’âge moyen était de 8,5 ans et le temps moyen entre le début de l’intervention et le diagnostic était de 13,2 semaines. Après 1 an d’intervention, le taux de rétention étaient de 72,6 %, 258 rencontres ont été menées sur 362 planifiées (taux de présence 71,6%) et la moitié des participants (50,8 %) avaient participé à au moins 4 rencontres de suivi. En conclusion, peu après le traitement d’un cancer pédiatrique, la santé CM est influencée par l’âge au diagnostic et l’évolution de l’IMC pendant les traitements, et le métabolisme des HDL tant par l’âge que les doses de doxorubicine reçues. Les biomarqueurs du statut inflammatoire peuvent servir d’indicateur de la santé CM chez ces patients. Par ailleurs, l’implantation d’une intervention nutritionnelle impliquant les patients et leurs parents tôt après le diagnostic d’un cancer pédiatrique est faisable et constitue une stratégie à prioriser afin d’optimiser la santé CM de cette population à court et à long terme. Dans leur ensemble, nos travaux contribuent à améliorer la prise en charge et les méthodes d’interventions auprès des enfants et des adolescents diagnostiqués d’un cancer.Due to medical advances, the 5-year survival rate for children and adolescents diagnosed with cancer is now approximately 85%. Despite these encouraging statistics, in adulthood, survivors of pediatric cancer are at risk of developing several health problems including cardiovascular disease and cardiometabolic complications (CM) such as hypertension, insulin resistance, dyslipidemia and abdominal obesity. In this context, it is important to increase the knowledge of the evolution and etiology of these sequelae to improve early management. However, to date, only a few studies have described the CM health of patients in the short term after the end of treatment and the factors associated with the early development of these complications remain unknown. Cancer and its treatment cause a pro-inflammatory & pro-oxidative state that can lead to the development of CM complications. In parallel, the treatment period is characterized by changes in dietary habits, sedentary behavior, and increased body mass index (BMI), which may persist after treatment ends. In the long term in pediatric cancer survivors, obesity status at the end of treatment and some inflammatory biomarkers have been associated with the presence of CM complications. In addition, HDL composition is different in long-term survivors of acute lymphoblastic leukemia compared with healthy controls. Given the importance of these factors, it is critical to describe them in the short term, after the end of treatment. In addition, obesity at diagnosis and increasing BMI during treatment negatively influence prognosis and the occurrence of serious side effects during treatment. However, most nutritional interventions in pediatric oncology do not address the issue of significant weight gain during treatment. Thus, it seems important to evaluate the possibility of implementing strategies focusing on the promotion of healthy lifestyle habits early after the diagnosis of pediatric cancer in order to improve the nutritional status, quality of life and possibly the CM health of patients in the short and long term. The work in this thesis aims to: i) describe the CM health of pediatric oncology patients shortly after treatment, ii) elaborate, through a literature review, on the role of inflammatory and oxidative status related to pediatric cancer and its treatments in the development of CM complications, iii) evaluate the associations between changes in BMI during the pediatric cancer care trajectory and CM complications as well as inflammatory status; vi) detail the lipid and protein composition of patients' HDL shortly after completion of pediatric cancer treatments and; v) determine the feasibility of early nutritional intervention in children and adolescents newly diagnosed with cancer. Two cohorts of patients were recruited as part of the VIE (Valorisation, Implication, Education) study at CHU Sainte-Justine. First, 80 patients followed in hemato-oncology were met on average 1.4 ± 0.8 year after the end of their treatment for pediatric cancer. Of this group, 56.3% were girls, 43.8% had been treated for leukemia. The mean age at encounter was 11.8 years (min - max: 4.5 - 21.0). The proportion of CM complications observed was 26.3% for high blood pressure (BP), 8.1% for prediabetes, 35.0% for dyslipidemia, and 11.5% for obesity. Adolescents (≥ 10 years of age at diagnosis) were more likely to have elevated BP, dyslipidemia, and ≥ 2 CM complications than children. Being overweight or obese after treatment was associated with higher levels of insulin, HOMA-IR, leptin, and plasma leptin/adiponectin ratio. In patients who were overweight or obese at the end of treatment, the change in BMI was related to the level of adipokines (leptin and leptin/adiponectin ratio) after treatments. In addition, HDL3 fractions were enriched in triglycerides in patients who were dyslipidemic at assessment compared with the normolipidics, and in those who had been treated with doxorubicin doses ≥90 mg/m2 compared to lower doses. In parallel, a one-year nutrition intervention, including an initial assessment and six follow-up visits every two months, was conducted with 61 participants. Of these, 51.6% were boys, the mean age was 8.5 years, and the mean time from intervention initiation to diagnosis was 13.2 weeks. After 1 year of intervention, the retention rate was 72.6%, 258 visits were held out of the 362 planned (71.6% attendance rate) and half of the participants (50.8%) had attended at least 4 follow-up visits. In conclusion, shortly after treatment of pediatric cancer, CM health is influenced by age at diagnosis and BMI changes during treatment, and HDL metabolism by both age and doses of doxorubicin received. Biomarkers of inflammatory status may serve as an indicator of CM health in these patients. Furthermore, implementation of a nutritional intervention involving patients and parents early after diagnosis of pediatric cancer is feasible and is a strategy to prioritize to optimize CM health in this population in the short and long term. Taken together, our work contributes to improve the management and intervention methods for children and adolescents diagnosed with cancer

    University of Windsor Graduate Calendar 2023 Spring

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    https://scholar.uwindsor.ca/universitywindsorgraduatecalendars/1027/thumbnail.jp

    University of Windsor Graduate Calendar 2023 Winter

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    https://scholar.uwindsor.ca/universitywindsorgraduatecalendars/1026/thumbnail.jp

    The Impact of Heterogenous Cell Populations on Impedance-Based Cell Analysis

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    Many in vitro studies for drug development are based on population-averaging measurement techniques without giving information about cell-to-cell variability within the cell ensembles under study. However, such heterogeneities in cell cultures are omnipresent and can arise by several causes, like spontaneous genetic mutations, different metabolic situations or different cell cycle states of individual cells. Moreover, microenvironmental conditions, like cell crowding, might force cell ensembles to form subpopulations with distinct characteristics. Therefore, single phenotypically different subpopulations may be overseen or averaged responses across different subpopulations might not reflect the majority of the cells, leading to misinterpretations of data – one possible reason for the high failure rate in clinical trials. This thesis addressed the fundamental question of how cell-to-cell variability in populations influence the signal of population-based assays by using three different approaches. The first project addressed the impact of evenly distributed heterogeneities within cell populations, introduced by mixing a cell line expressing a certain G protein-coupled receptor (GPCR) with a cell line not expressing this receptor type, on the impedance-based cell analysis. The second project focused on the development of an impedance-based assay for the future purpose of spatiotemporally introducing heterogeneities in an isogenic cell population, expressing a certain GPCR, by switching an appropriate, photochromic ligand by illumination. The third project addressed the quantification of the impact of heterogeneities within cell populations on the impedance-based cell analysis in a theoretical manner. The first project focused on the impact of cell-to-cell variability on the population-based impedance signal by mixing cell lines in different ratios prior to the seeding onto the co-planar gold electrodes. The evenly distributed heterogeneities in the resulting cell populations were generated by co-culturing two cell lines with one of them expressing a GPCR predominantly coupled to one of the three main canonical G-protein pathways (Gq, Gs, Gi/o). A protocol was established to obtain co-cultures with distinct cell ratios resulting in well-defined areal receptor densities (ARD) as verified by supported microscopic staining studies. The stimulation of cell ensembles with varying ARD by the GPCR's endogenous ligands was analyzed in detail by wholistic impedance-based cell assays. Efficacies and potencies, which describe the maximal agonist effect and the activity of a drug, were compared to those of the pure and original cell lines. It was shown that both parameters were dependent on the ARD and the coupled signaling cascades in distinct ways: for the Gq pathway, efficacy decreased non-linearly with decreasing ARD, while the Gs- and Gi/o-pathways exhibited an almost linear dependency of efficacy on the ARD. The potencies observed for the Gq- and Gi/o-coupled signaling pathway decreased with decreasing ARD, while the potency of the Gs-pathway was almost independent of the ARD. Simple simulations indicated that underlying communication processes between stimulated and non-stimulated cells within the populations under study may be responsible for these trends. Additionally, two proximal assay techniques were used to assist the interpretation of impedance analysis and to assign the impact of the ARD on the signal to a certain part of the signaling cascade. The radioligand competition binding assay confirmed the correct co-culturing strategy for such heterogeneous cell populations and confirmed the corresponding potency to be independent of the population composition. Population-based Ca2+ imaging highlighted the impact of altering the ARD on second messenger mobilization. Again, the ARD did not affect the potency, but the analysis of the response on a single-cell level proposed cell communication as a potential mechanism explaining the dependency of impedance on ARD. Moreover, the stimulation of a co-culture, consisting of two GPCR-expressing cell lines, was analyzed impedimetrically. The outcomes indicated that the potency dependency on the ARD was caused by the simultaneous activation of two different signaling pathways. The obtained data confirmed that the impact of artificially introduced heterogeneities in the cell population under study on the obtained impedance signal was indeed significant. Nevertheless, it remains elusive, whether these results can be translated to other cell lines or other GPCRs. This project addressed the fundamental question of areal heterogeneities influencing the impedance signal. However, further studies on cell ensembles with different compositions and other measurement techniques have to be carried out to obtain a broader picture of such impacts on population-based measurements and its significance for the drug development process. In the second project of this thesis, an assay was developed for the future purpose of introducing cell-to-cell variability within isogenic cell populations by spatiotemporal illumination of photochromic GPCR-ligands, which can be toggled between their bioactive and -inactive isomer. Thus, it was required to establish a protocol to active in situ such a ligand by online irradiation with light and to monitor the cell responses in a time-resolved manner. The wholistic impedance-based cell assay was appropriate to monitor the in situ toggling of a model photoswitchable ligand for a Gq-coupled receptor. To accomplish the superordinate goal, it will be necessary to establish a measurement setup, which is capable of spatiotemporal illumination of the cell culture, so that a small subpopulation can be stimulated in a spatiotemporally well-defined manner after the systemic addition of the bioinactive species of a photoswitchable ligand. The third part of this thesis addressed the impact of heterogeneous cell populations on the impedance readout by theoretical means. For this purpose, a MATLAB-based algorithm was developed, capable of simulating different cell types following the electric cell-substrate impedance sensing (ECIS) model. In contrast to the conventional mode, which assumes global cell-related parameters (α for the cell-substrate contacts, Rb for the cell-cell contacts, Cm for the cell membrane capacitances) for the whole population, the new approach emulated cell populations by cell-related parameters, each showing a Gaussian distribution with a mean and a deviation value. After successful validation of the underlying algorithm, discrepancies from the ECIS model using global parameters were found for such populations with heterogeneous cell-related parameters for three distinct cell types, emulating leaky, moderately tight, and tight cells. Especially the deviation of the Gaussian-distributed parameters α and Rb had a big impact on the spectra. In direct comparison to the reference, which was a homogenous cell population with global parameter values being equal to the mean values of the Gaussian distribution, a systematical misestimation could be found for α (up to 110 % of the reference value) and underestimation for Rb (down to 78 % of the reference value) when the deviation values were set to 30 % of the mean values. In contrast, Cm was found to be very robust for deviations up to 30 % (100 % of the reference value). In summary, the thesis has demonstrated in an experimental and theoretical manner that cell-to-cell variability has indeed major impacts on the population-based impedance signal, having the potential to misdirect data interpretation. These can affect fundamental as well as pharmacological research. Thus, it is crucial to address such heterogeneities within cell populations in future studies using population- as well as single-cell-based assay techniques

    Deep Learning, Shallow Dips: Transit light curves have never been so trendy

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    At the crossroad between photometry and time-domain astronomy, light curves are invaluable data objects to study distant events and sources of light even when they can not be spatially resolved. In particular, the field of exoplanet sciences has tremendously benefited from acquired stellar light curves to detect and characterise a majority of the outer worlds that we know today. Yet, their analysis is challenged by the astrophysical and instrumental noise often diluting the signals of interest. For instance, the detection of shallow dips caused by transiting exoplanets in stellar light curves typically require a precision of the order of 1 ppm to 100 ppm in units of stellar flux, and their very study directly depends upon our capacity to correct for instrumental and stellar trends. The increasing number of light curves acquired from space and ground-based telescopes—of the order of billions—opens up the possibility for global, efficient, automated processing algorithms to replace individual, parametric and hard-coded ones. Luckily, the field of deep learning is also progressing fast, revolutionising time series problems and applications. This reinforces the incentive to develop data-driven approaches hand-in-hand with existing scientific models and expertise. With the study of exoplanetary transits in focus, I developed automated approaches to learn and correct for the time-correlated noise in and across light curves. In particular, I present (i) a deep recurrent model trained via a forecasting objective to detrend individual transit light curves (e.g. from the Spitzer space telescope); (ii) the power of a Transformer-based model leveraging whole datasets of light curves (e.g. from large transit surveys) to learn the trend via a masked objective; (iii) a hybrid and flexible framework to combine neural networks with transit physics

    On Reward Structures of Markov Decision Processes

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    A Markov decision process can be parameterized by a transition kernel and a reward function. Both play essential roles in the study of reinforcement learning as evidenced by their presence in the Bellman equations. In our inquiry of various kinds of "costs" associated with reinforcement learning inspired by the demands in robotic applications, rewards are central to understanding the structure of a Markov decision process and reward-centric notions can elucidate important concepts in reinforcement learning. Specifically, we study the sample complexity of policy evaluation and develop a novel estimator with an instance-specific error bound of O~(Ď„sn)\tilde{O}(\sqrt{\frac{\tau_s}{n}}) for estimating a single state value. Under the online regret minimization setting, we refine the transition-based MDP constant, diameter, into a reward-based constant, maximum expected hitting cost, and with it, provide a theoretical explanation for how a well-known technique, potential-based reward shaping, could accelerate learning with expert knowledge. In an attempt to study safe reinforcement learning, we model hazardous environments with irrecoverability and proposed a quantitative notion of safe learning via reset efficiency. In this setting, we modify a classic algorithm to account for resets achieving promising preliminary numerical results. Lastly, for MDPs with multiple reward functions, we develop a planning algorithm that computationally efficiently finds Pareto-optimal stochastic policies.Comment: This PhD thesis draws heavily from arXiv:1907.02114 and arXiv:2002.06299; minor edit

    Duality methods for stochastic optimal control problems in finance

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