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Efficient Time Series Clustering: A Distance-Based Feature Engineering Framework with Minimal Hyperparameter Tuning
No full textTime series clustering is a critical tool used to extract valuable insights from time series data. However, challenges accompany time series clustering due to time series unique properties, such as noise and data shifts. One major challenge lies in selecting appropriate distance measures used for clustering algorithms, significantly impacting the overall clustering performance. This research introduces an improved time series clustering approach based on a novel feature extraction technique that is founded on an enhanced vector-based distance measure. Our feature extraction process, named DBFE, converts time series data into distance-based feature vectors using the enhanced distance measure, which is both efficient and hyperparameter-free, overcoming time series challenges while remaining robust to noise, outliers, and simple shifts in data. Experimental results show that our proposed approach enhances clustering performance compared to state-of-the-art methods. When tested on 22 time series datasets and compared with traditional clustering approaches, clustering over DBFE resulted in better clustering results on 18 datasets, equivalent results on two datasets, and only failed on two datasets, one of which is not suitable for clustering and the other is too small to evaluate on. DBFE has also been expanded to multivariate data and, hence, is suitable for a wider range of time series applications in various domains such as medicine, finance, and marketing. By applying this enhanced clustering approach, researchers could more accurately discover patterns, detect anomalies, and recognize dynamic changes in data
Testing, Validation, and Numerical Modeling of Rammed Earth Construction Materials
Get PDFIn recent years, rammed earth is getting more popular due to its environmental benefits mainly in terms of its low carbonic gas emissions compared to conventional concrete construction. In addition to its use in recent construction projects, maintaining the heritage of rammed earth buildings all over the world requires scientific analysis and knowledge in order to evaluate their appropriateness. This technique is considered a cheap way to build as it requires material which is already available on the site. For this reason, rammed earth construction is often used to solve sheltering problems in developing countries. Aesthetically, the horizontal layering varying from red to orange and yellowish-grey make rammed earth an appealing material. Its environmental, economic, and aesthetic components make rammed earth construction a considerable option to meet project requirements. Due to the limited research in modeling rammed earth, this research aims to input rammed earth material into the finite element software “ABAQUS/CAE” and model the behavior of earth samples and walls under compressive load. Samples from a region of Ghazze in Bekaa, Lebanon, were taken and tests were made to meet the recommended properties for rammed earth usage present in previous literatures. These samples were tested for conventional soil properties and then calibrated to validate their adoption in a rammed earth constitutive model in ABAQUS. Several nonlinear modeling techniques were assessed to reach the proper approach for rammed earth numerical simulation, such as Mohr-Coulomb, Drucker-Prager, and Concrete Damage Plasticity (CDP), where CDP converged the most with the experimental test in terms of shape and hardening, compared to the Mohr-Coulomb and Drucker-Prager which do not model the softening behavior of the material
Deciphering Nature's Secret: Genome Mining in Natural Product Drug Discovery.
No full textBackground: Antimicrobial resistance (AMR) stands as a threat against global health, rendering once-effective antibiotics impotent against bacterial infections. Various factors contribute to the emergence of AMR, including overuse and misuse of antibiotics in human healthcare and agriculture sectors, among others. Moreover, the challenge is further intensified by the antimicrobial discovery void that has emerged subsequent to the golden era of antimicrobials. During this period, the development of novel antimicrobials stagnated, creating a scarcity of effective therapeutic agents. In this context, natural products have regained prominence as valuable reservoirs for new antimicrobial agents. Microorganisms, led by evolutionary pressures to outcompete each other, are producers of secondary metabolites (SM) with antimicrobial properties. Focusing on the microbial frontlines, this thesis proposes exploring the untapped potential of soil microorganisms through genome mining, utilizing both metagenomics and isolate genomics approaches. While traditional culture-based methods have limitations in capturing the full range of microbial diversity present in complex environments, Metagenomics offers a powerful tool to unlock biosynthetic potential within the genomes of uncultured bacteria. Simultaneously, isolate genomics provides a targeted approach to study individual microorganisms, enhancing our understanding of their genomic makeup and biosynthetic capabilities. This integrated approach holds the key to discovering novel antimicrobial compounds that may evade traditional cultivation methods. Through a combination of innovative techniques and a focus on nature's own defenses, this study seeks to contribute to the revitalization of antimicrobial drug discovery in the face of an evolving global health crisis.
Materials and Methods: Soil samples from various locations in Lebanon undergo DNA extraction, followed by sequencing using short-read and long-read platforms. Bioinformatics analysis, including assembly, binning, taxonomic classification, and gene annotation, is conducted using tools like antiSMASH for biosynthetic gene cluster (BGC) identification. Genetic Networking and Molecular networking via a high-resolution liquid chromatography mass spectrometer (HR-LC-MS) and metabolomics aid in compound identification and biosynthetic pathway elucidation.
Results: We observed striking differences in BGC abundance across microbial taxa, with Streptomyces species exhibiting a significantly higher number of BGCs compared to other groups. Additionally, the limited number of BGCs in certain microorganisms may facilitate their validation and downstream application, simplifying the process of identifying and characterizing bioactive compounds. Furthermore, our investigation into relatedness revealed that BGCs were only related across the same Streptomyces genera, emphasizing the need for comprehensive exploration and characterization of BGCs across microbial taxa. Comparing these results to the molecular network, we observed that many BGCs producing known compounds were not represented, indicating the presence of unexpressed BGCs, and underscoring the importance of genome mining in identifying cryptic biosynthetic potential
3D Autocomplete: Enhancing UAV Teleoperation with AI in the Loop
No full textManually teleoperating a flying robot can be a demanding task, especially for users
with limited levels of experience. This is primarily due to the nonlinear properties of
such robots in addition to the difficulty of controlling various degrees of freedom at
the same time. To help mitigate such limitations, this thesis proposes a framework
named ‘3D Autocomplete’ that aids users in teleoperation. It uses artificial intelligence
to predict in real-time the operator’s intended motion, and mixed reality to
convey the predicted motion to the user. Previous Autocomplete systems focused on
different 2D motions in the same plane (line, arc, sine). However, since many drone
tasks take place in a three-dimensional environment, 3D Autocomplete primarily
assists users in navigating challenging 3D motions around 3D geometric primitives
(cylinder, cone, and box). During teleoperation, the framework uses a real-time
change point detection algorithm called ‘just-in-time’ to monitor the user’s input,
and deep learning to early predict the motion type as one of predefined 3D motions.
Then, the predicted motion is augmented into the first person view in real-time
using a virtual reality headset. Finally, if the users accept the proposed trajectory,
3D Autocomplete completes their desired motion autonomously. We validate the
proposed mixed reality teleoperation approach by conducting different experiments
on a simulated quadrotor. The results illustrate 3D Autocomplete advantages over
traditional teleoperation methods through both subjective and objective evaluations
conducted via human subject experiments. The system achieves its primary goal of
reducing the users workload, and improves task completion time and covered distance
by at least 30% compared to traditional teleoperation. Moreover, it enhanced
the system performance and trajectory smoothness by approximately 50%
Perceived Quality of School Life of High School Students on Greater Beirut: The Role of Academic and Social Factors and School Facilities and Services
No full textThe purpose of this quantitative descriptive correlational study was to assess the perceived quality of school life (QSL) of Lebanese high school students in Greater Beirut, compare the QSL of males and females and between the different grade levels, investigate the extent of the correlational relationship of each of academic, social, facilities and services domains with their total QSL score, and determine which of these three components relates the strongest with total QSL. The conceptual model of QSL used in the study follows the bottom-up spillover theory. The study was conducted on 442 students from grades 10 to 12 from private English speaking schools in Greater Beirut. To answer the research questions, descriptive statistics was used along with multiple correlational and regression analyses. Results indicated low levels of total QSL, with levels ranging from neutral to dissatisfied on the various domains. Males and females showed no significant difference and grade 12 students showed highest levels of QSL. School facilities and services showed the greatest correlation and was the strongest predictor of QSL. Social satisfaction was the second greatest predictor. Recommendations for further research and for schools in Lebanon to heighten the wellbeing of their students have been made based on the results
Stuttering-induced epigenetic modifications of the Ca 2+ - dependent K + and hyperpolarization-activated inward currents in the basal-ganglia projecting cortical neurons of songbirds
No full textStuttering is a neurodevelopmental disorder marked by disrupted speech flow characterized by repetition of sounds, syllables, or words; prolongation of sounds; and interruptions in speech known as blocks. Despite its importance and our current advances in technology, the pathophysiological mechanisms of stuttering remain largely unknown. Vocal control and learning in both songbirds and humans rely heavily on auditory feedback. Continuous delayed auditory feedback (cDAF) is a technique that has been shown to significantly disrupt speech fluency in humans and induce stuttering in songbirds. Focusing on the cortical nucleus HVC, a crucial area in the song system necessary for song learning and production, we examined the intrinsic neuronal properties of a major class of neurons known as the basal-ganglia projecting HVC neurons, which had been shown to exhibit altered firing behaviors under stuttering conditions.
Building on a biophysically realistic mathematical model incorporating ionic currents which had been pharmacologically identified for this class, we started by constructing an error function customized to this class of neurons given their characteristic spiking patterns, with the aim of generating excellent fits and predictions between the biological recordings and model simulations. We then used bifurcation analysis to study the behavior of the dynamical system and conducted exhaustive parameter searches on a high-performance computing cluster at the American University of Beirut, where we explored a relatively large space of key parameters that had been identified by the bifurcation analysis and that govern the neuronal behavior. The intensive parameter searches were conducted on two datasets of basal-ganglia projecting neurons, a control group of adult zebra finches (N=160 neurons from 35 birds) and another adult group (N=60 neurons from 9 birds) that had been subjected to cDAF for ≥6 days leading to their stuttering. Our model simulations highlighted key roles for two principle ionic channels that had been modified during stuttering leading to the changes observed in the corresponding firing behaviors. In particular, stuttering induced a down-regulation in the Ca2+- dependent K+ current (I_SK) and an upregulation in the hyperpolarization-activated inward current (I_H). Our results link, for the first time, possible channelopathies or epigenetic modifications in I_SK and I_H to the stuttering neurological disorder after cDAF induction. Further basic and clinical follow up have the potential to develop new therapeutics for managing stuttering
The Association Between Social Isolation and Cognitive Function in Older Adults in Urban, Fringe, and Rural Regions of Lebanon
No full textBackground: The ongoing rectangularization of the global age structure signals that one out of four persons will be 65+ by 2050. Studies have shown that altered cognitive function (e.g. cognitive decline) and social status (e.g. social isolation) are significant determinants of health and quality of life in the older adult. Although significant public health and epidemiologic efforts are invested in examining the relationship between these two notions, but it remains poorly understood. The aim of this study is to evaluate the link between social isolation and cognitive decline in the Lebanese older adult and to investigate whether this association is affected by geographical residence. Methods: Statistical analysis methods are applied to secondary data derived from two national cross-sectional studies that assessed the prevalence of dementia in older adults. Out of a 744 cohort, comprised of older adults from urban, fringe and rural regions of Lebanon, 728 participants were included in this study. Living in social isolation was measured via an index score for 5-items: marital status, employment, social networking with children and relatives, social networking with friends and neighbors, and social participation. Living with cognitive decline was assessed via the screening tool, A-IQCODE: a 16-item questionnaire that assesses several cognitive domains. Univariate and multivariate logistic regression analysis evaluated the association between social isolation and cognitive decline while accounting for key confounders and the moderator, area of residence. To examine the effects of the latter on the former association, regression models were stratified by area of residence. All models were adjusted to cluster effect, the sampling technique. Results: The prevalence of cognitive decline and social isolation among older adults was 21% and 19%, respectively. After adjustment for age, gender, education, income, chronic diseases, mental illness and area of residence, the social isolation index score was significantly associated with cognitive decline (aOR 1.45, 95% CI 1.17 – 1.81). Only employment (aOR 3.04, 95% CI 1.19 – 7.75) and social participation (aOR 1.85, 95% CI 1.07 – 3.20) showed significant association with cognitive decline on separate regression models. When all indicators were included in a single regression model, social participation lost significance (aOR 1.63, 95% CI 0.84 – 3.17). All interaction terms for area of residence were not significant, thus we observed no effect modification by area of residence. Upon stratification of the multivariate regression analysis, the social isolation index score was significantly associated with cognitive decline in urban (p 0.03) and rural (p 0.02) areas but not in the fringe (p 0.31). 1 Conclusion: Our findings reveal much higher prevalence of cognitive decline in Lebanese older adults as compared to previous reports. Along with the notable prevalence of social isolation and the finding of a significant differential association with cognitive decline across geographical regions, our study is the first to describe two burdening public health issues in a large and representative cohort of older adults in Lebanon. Future research into the causal relationship and the socio-environmental risk factors for social isolation and cognitive decline could lay the groundwork for a much-needed policy and public health interventions
Investigating the Interplay between Growth Differentiation Factor 15 (GDF-15) and Neutrophil Extracellular Traps (NETs) in the Pathophysiology of Diabetic Nephropathy
No full textBackground: Diabetes mellitus is a heterogeneous group of metabolic disorders characterized by hyperglycemia due to an absolute or relative deficit in insulin secretion, action, or both. The increased prevalence of diabetes globally has led to an increase in the number of both microvascular and macrovascular complications. Among the microvascular complications is diabetic nephropathy, also known as Diabetic Kidney Disease (DKD), which is the single strongest predictor of mortality in patients with diabetes. The main hallmarks of DKD are hyperglycemia-induced progressive renal dysfunction, inflammation, and fibrosis; all of which are mediated by the overproduction of reactive oxygen species (ROS). Growth Differentiation Factor 15 (GDF-15), a member of the TGF-β superfamily, that has been previously recognized for its role in cellular stress response and apoptosis, has recently emerged as a potential mediator in the intricate network of inflammatory pathways associated with DKD. Yet, it is important to note that in the context of DKD, the dual nature of GDF-15—both protective and deleterious—is a subject of debate. On the other hand, neutrophils, via the process of NETosis, play a crucial role in the pathogenesis of DKD through the release of Neutrophil Extracellular Traps (NETs), a novel form of neutrophil-specific cell death. Herein, we investigate the role of GDF-15 in the pathogenesis of DKD and its crosstalk with Neutrophil Extracellular Traps (NETs) in type 2 diabetes. Hypothesis: In this thesis work, we hypothesize that the inhibition of GDF-15 attenuates NETosis, thereby preventing the progression of diabetic kidney disease. Design: T2DM was induced using the high fat diet/STZ model in two sets of experiments over a short- (8 weeks) and long- (15 weeks) term periods respectively. In the first study, C57BL/6J mice were divided into six groups: control, control receiving GDF-15 monoclonal antibody AV-380 (7.5mg/kg or 20mg/kg), T2DM, and T2DM receiving AV-380 (7.5mg/kg or 20mg/kg) for 8 weeks. In the second study, C57BL/6J mice were divided into four groups: control, T2DM, and T2DM receiving AV-380 (7.5mg/kg or 20mg/kg) for 15 weeks. Functional, histopathological, and molecular studies were performed on kidney tissues from all groups.
Results: Our findings show that elevated GDF-15 levels in T2DM mouse models of both studies lead to increased NADPH-associated ROS overproduction, contributing to DKD. Treatment of T2DM mice with a neutralizing anti-GDF-15 antibody (AV-380) attenuated renal injury as assessed by reductions in urinary albumin excretion, urinary albumin to creatinine ratio, proteinuria, blood urea nitrogen levels, glomerular hypertrophy, glomerulosclerosis, and fibrosis. Additionally, inhibition of GDF-15 signaling significantly decreased T2DM-associated NETs formation, oxidative stress, NADPH oxidase activity and NOX4 expression. Our results further indicate that GDF-15 acts upstream of NETs and NOX4 in mediating renal injury. Furthermore, short-term (8 weeks) and long-term (15 weeks) studies confirm that higher doses of AV-380 (20 mg/kg) are more effective in reducing GDF-15 levels and its pathological effects in the context of DKD. Conclusion: Our findings suggest an interplay between GDF-15 and NETosis in the context of DKD, resulting in NADPH oxidase-dependent ROS overproduction. The inhibition of GDF-15 signaling with the AV-380 monoclonal antibody restores renal function, reduces oxidative stress, and regulates NETosis, thereby slowing DKD progression. Taken together, targeting GDF-15 signaling pathway and activity through pharmacological interventions could present a promising strategy for treating DKD
CCECS Frontliners Handbook
No full textLearn more about CCECS mission, vision, and operational framework through the CCECS Frontliners Handboo
Identifying Alternative Approaches to Prevent and Counter Violent Extremism: A Case Study of Iraq Post US Intervention
Get PDFSince the US invasion of Iraq in 2003, the authorities faced massive security challenges and failed to achieve peace and stability. The US led interim government CPA miscarried the navigation through existing dynamics within Iraq. Its failure to recognize the full extent of this operation and the neglect of the so called “essence” of Iraqi society, led ultimately to rise of violence and fostered extremist forces like ISIL. The US led intervention caused the downfall of the Ba'athist regime, hence created a “profound power vacuum”. A series of wrongful political decisions intensified existing tensions by large. The CPA’S lack of comprehension and its deficiency in planning for conflict stabilization and governance left Iraq vulnerable to violent insurgency and internal turmoil until today. Such failed intervention and attempt to reach regional stability, introduces the value in researching alternative approaches to peace building and prevention of rising extremism. As suggested by experts in the field, the empowerment and the involvement of Iraqi local forces, such as tribes, are crucial in achieving stability. This paper is a preliminary study of the subject on alternative approaches to counter violence and prevent extremism in conflict prone regions. Methodologically it is based on existing academic material and previous studies. The key finding of this project is the necessity of including local decision makers as an enhanced and sustainable method to establish stability, compared to the failures and fatalities caused by US intervention. This work is a pathway to a future ethnography to be conducted in Jazira, Iraq