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Exploring Spatiotemporal Dynamics, Seasonality, and Time-of-Day Trends of PM 2.5 Pollution with a Low-Cost Sensor Network: Insights from Classic and Spatially Explicit Markov Chains

SSRN

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SSRN 2024年

作者： Biancardi, Michael Kang, Wei Xiao, Ting Grubesic, Tony Nelson, Jake Liang, Lu Department of Geography and the Environment University of North Texas DentonTX76203 United States Department of Computer Science and Engineering University of North Texas DentonTX United States Department of Information Science University of North Texas DentonTX United States School of Public Policy University of California Riverside RiversideCA92521 United States Department of Geosciences Auburn University United States Department of Landscape Architecture and Environmental Planning University of California Berkeley United States

Fine particulate matter (PM2.5) poses a notable threat to public health and the environment. Given its extensive occurrence and consequential impacts in urban areas, understanding the spatial-temporal patterns of air pollution at a granular level is crucial for shaping city policies and health assessment. This study employs data from a comprehensive low-cost air quality sensor network to explore and contrast classic and spatially explicit Markov chains in characterizing the seasonality and intra-daily variations of PM2.5. This new approach surpasses the traditional daily assessment focus, marking a pioneering step in urban air quality research. This study underlines distinctive PM2.5 seasonality, demonstrating a prevalence of the "Good" air quality state predominantly in summer and least in winter. Moreover, our analysis highlights midday as the peak period for the "Good" state, with mornings and nights showing a lower prevalence. Notably, the impact of temporal scale on spatial Markov analysis is substantial, revealing a broader range of air pollution states, heightened stability, and reduced variation between time intervals compared to the daily scale. Finally, our study accentuates significant spatial effects within PM2.5 dynamics, emphasizing the imperative of integrating spatially explicit models in such analytical contexts. © 2024, The Authors. All rights reserved.

关键词： Sensor networks

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Grid connections and inequitable access to electricity in African cities

Nature Cities

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Nature Cities 2025年 1-9页

作者： Jessica Kersey Daniel M. Kammen Civian Kiki Massa June Lukuyu Judith Mbabazi Jay Taneja Veronica Jacome Energy and Resources Group University of California Berkeley CA USA Goldman School of Public Policy University of California Berkeley CA USA Electrical and Computer Engineering University of Massachusetts Amherst MA USA Department of Electrical and Computer Engineering University of Washington Seattle WA USA Urban Action Lab Makerere University Kampala Uganda Manning College of Information and Computer Sciences University of Massachusetts Amherst MA USA Geography Environment and Urban Studies College of Liberal Arts Temple University Philadelphia PA USA

As the Global South rapidly and inequitably urbanizes, cities are at the forefront of efforts to address energy-related dimensions of poverty. In many African cities, electricity via a connection to a grid—the gold standard of electrification—has not substantially displaced smoky, polluting fuels. Among low-income communities, connections tend to be based on improvised, informal arrangements with local intermediaries. The nature and level of access these connections provide is not well understood and cannot be easily measured using existing energy access metrics such as the Multi-Tier Framework. This study provides a grounded, empirical analysis of grid connections across 25 informal settlements in the Ugandan capital city of Kampala. Using a mixed-methods approach that incorporates surveys, interviews and remote power quality monitoring, we trace electrical and financial flows between the utility, supply intermediaries and end users. We identify 29 unique configurations of these flows—which we term service arrangements—that provide electricity of varying and overall limited levels of affordability, reliability, voltage stability, precarity, autonomy and safety. Our evidence suggests that the grid delivers highly inequitable electricity services that fall short of aspirations of modern energy for the city’s most vulnerable communities.

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engineering Casimir interactions with epsilon-near-zero materials

arXiv

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arXiv 2021年

作者： Camacho, Miguel Gong, Tao Spreng, Benjamin Liberal, Iñigo Engheta, Nader Munday, Jeremy N. Department of Electrical and Systems Engineering University of Pennsylvania PhiladelphiaPA19104 United States Department of Electronics and Electromagnetism Universidad de Sevilla Seville41012 Spain Department of Electrical and Computer Engineering University of California DavisCA95616 United States Department of Materials Science and Engineering University of California DavisCA95616 United States Department of Electrical and Electronic Engineering Public University of Navarra Pamplona31006 Spain

In this paper we theoretically demonstrate the tunability of the Casimir force both in sign and magnitude between parallel plates coated with dispersive materials. We show that this force, existing between uncharged plates, can be tuned by carefully choosing the value of the plasma frequency (i.e., the epsilon-near-zero frequency) of the coating in the neighborhood of the resonance frequency of the cavity. The coating layer enables a continuous variation of the force between four limiting values when a coating is placed on each plate. We explore the consequences of such variation when pairs of electric and magnetic conductors (i.e. low and high impedance surfaces) are used as substrates on either side, showing that this continuous variation results in changes in the sign of the force, leading to both stable and unstable conditions, which could find interesting potential applications in nanomechanics including nanoparticle tweezing. Copyright © 2021, The Authors. All rights reserved.

关键词： Quantum theory

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Wi-Fi Router Signal Coverage Position Prediction System using Machine Learning Algorithms

Wi-Fi Router Signal Coverage Position Prediction System usin...

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Sustainable Computing and Smart Systems (ICSCSS), International Conference on

作者： Rajalaxmi Hegde Sandeep Kumar Hegde Kdv Prasad Ved Srinivas Tanmoy De V Dankan Gowda Department of Computer Science and Engineering NITTE(Deemed to be University) NMAM Institute of Technology Nitte Karnataka India Symbiosis Institute of Business Management (SIBM) Symbiosis International (Deemed University) (SIU) Off Bangalore Highway Kothur Mandal Village Mahabubnagar Hyderabad Telangana India Public Policy Thiagarajar School of Management Madurai Tamil Nadu India Symbiosis Institute of Business Management Hyderabad Symbiosis International (Deemed University) Pune India Department of Electronics and Communication Engineering BMS Institute of Technology and Management Bangalore Karnataka India

As a popular topic, indoor positioning has gradually drawn the attention of both academia and business. Numerous location based services including healthcare, repository tracking, and security call for accurate estimation. An accurate estimation might be achieved by using additional location-sensing equipment, but this is not generally done because it would result in expensive brand specialization. A flexible and affordable location determination technique that exploits the already-existing WLAN infrastructure in indoor spaces has been designed without incurring additional costs, among all suggestions in the literature that include hardware and highly complex *** positioning strategy is becoming more popular. Soon in actual surroundings, WLAN will be able to be employed as part of an indoor positioning system. In comparison to similar systems, it is a good option in terms of accuracy, precision, and cost. It has also become the most user-friendly way, particularly with the widespread use of smartphones and tablet computers. In the literature, many machine learning algorithms such as cluster-filtered KNN and fuzzy c means algorithms have been proposed for the WiFi router signal coverage position prediction system but the disadvantage of these approaches is that it will consume much pre-processing time for reference points data and also these approaches found to be less accurate. In the proposed study, adaptive KNN-based machine learning model has been proposed for the WiFi signal coverage prediction system. The proposed method adjusts the value of K for each position by examining the relationship between the K value and the intensity of the received WiFi signal. This technique improves positioning accuracy by more than 30% when compared to the existing approach. The experimental results are conducted by applying various machine learning algorithms. The experimental finding demonstrates that the proposed approach obtained better results compared to tradi

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A Multi-Channel Ratio-of-Ratios Method for Noncontact Hand Video Based SpO2 Monitoring Using Smartphone Cameras

arXiv

引用

arXiv 2021年

作者： Tian, Xin Wong, Chau-Wai Ranadive, Sushant M. Wu, Min Department of Electrical and Computer Engineering University of Maryland College ParkMD20742 United States Department of Electrical and Computer Engineering Forensic Sciences Cluster Secure Computing Institute NC State University RaleighNC27695 United States Department of Kinesiology School of Public Health University of Maryland College ParkMD20742 United States

Blood oxygen saturation (SpO2) is an important indicator for pulmonary and respiratory functionalities. Clinical findings on COVID-19 show that many patients had dangerously low blood oxygen levels not long before conditions worsened. It is therefore recommended, especially for the vulnerable population, to regularly monitor the blood oxygen level for precaution. Recent works have investigated how ubiquitous smartphone cameras can be used to infer SpO2. Most of these works are contact-based, requiring users to cover a phone’s camera and its nearby light source with a finger to capture reemitted light from the illuminated tissue. Contact-based methods may lead to skin irritation and sanitary concerns, especially during a pandemic. In this paper, we propose a noncontact method for SpO2 monitoring using hand videos acquired by smartphones. Considering the optical broadband nature of the red (R), green (G), and blue (B) color channels of the smartphone cameras, we exploit all three channels of RGB sensing to distill the SpO2 information beyond the traditional ratio-of-ratios (RoR) method that uses only two wavelengths. To further facilitate an accurate SpO2 prediction, we design adaptive narrow bandpass filters based on accurately estimated heart rate to obtain the most cardiac-related AC component for each color channel. Experimental results show that our proposed blood oxygen estimation method can reach a mean absolute error of 1.26% when a pulse oximeter is used as a reference, outperforming the traditional RoR method by 25%. Copyright © 2021, The Authors. All rights reserved.

关键词： Hemoglobin oxygen saturation

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Impossibility theorems involving weakenings of expansion consistency and resoluteness in voting

arXiv

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arXiv 2022年

作者： Holliday, Wesley H. Norman, Chase Pacuit, Eric Zahedian, Saam Department of Philosophy and Group in Logic and the Methodology of Science University of California Berkeley United States Department of Electrical Engineering and Computer Science University of California Berkeley United States Department of Philosophy University of Maryland United States Stanford Institute for Economic Policy Research Stanford University United States

A fundamental principle of individual rational choice is Sen's γ axiom, also known as expansion consistency, stating that any alternative chosen from each of two menus must be chosen from the union of the menus. Expansion consistency can also be formulated in the setting of social choice. In voting theory, it states that any candidate chosen from two fields of candidates must be chosen from the combined field of candidates. An important special case of the axiom is binary expansion consistency, which states that any candidate chosen from an initial field of candidates and chosen in a head-to-head match with a new candidate must also be chosen when the new candidate is added to the field, thereby ruling out spoiler effects. In this paper, we study the tension between this weakening of expansion consistency and weakenings of resoluteness, an axiom demanding the choice of a single candidate in any election. As is well known, resoluteness is inconsistent with basic fairness conditions on social choice, namely anonymity and neutrality. Here we prove that even significant weakenings of resoluteness, which are consistent with anonymity and neutrality, are inconsistent with binary expansion consistency. The proofs make use of SAT solving, with the correctness of a SAT encoding formally verified in the Lean Theorem Prover, as well as a strategy for generalizing impossibility theorems obtained for special types of voting methods (namely majoritarian and pairwise voting methods) to impossibility theorems for arbitrary voting methods. This proof strategy may be of independent interest for its potential applicability to other impossibility theorems in social *** Codes 91B12, 91B14 Copyright © 2022, The Authors. All rights reserved.

关键词： Formal verification

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LEARNING TRANSFER OPERATORS BY KERNEL DENSITY ESTIMATION

arXiv

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arXiv 2022年

作者： Surasinghe, Sudam Fish, Jeremie Bollt, Erik M. Department of Ecology and Evolutionary Biology Yale University New HavenCT06520 United States Public Health Modeling Unit Yale School of Public Health New HavenCT06510 United States Clarkson Center for Complex Systems Science Department of Electrical and Computer Engineering Clarkson University 8 Clarkson Ave PotsdamNY13699 United States

Inference of transfer operators from data is often formulated as a classical problem that hinges on the Ulam method. The conventional description, known as the Ulam-Galerkin method, involves projecting onto basis functions represented as characteristic functions supported over a fine grid of rectangles. From this perspective, the Ulam-Galerkin approach can be interpreted as density estimation using the histogram method. In this study, we recast the problem within the framework of statistical density estimation. This alternative perspective allows for an explicit and rigorous analysis of bias and variance, thereby facilitating a discussion on the mean square error. Through comprehensive examples utilizing the logistic map and a Markov map, we demonstrate the validity and effectiveness of this approach in estimating the eigenvectors of the Frobenius-Perron operator. We compare the performance of Histogram Density Estimation (HDE) and Kernel Density Estimation (KDE) methods and find that KDE generally outperforms HDE in terms of accuracy. However, it is important to note that KDE exhibits limitations around boundary points and jumps. Based on our research findings, we suggest the possibility of incorporating other density estimation methods into this field and propose future investigations into the application of KDE-based estimation for high-dimensional maps. These findings provide valuable insights for researchers and practitioners working on estimating the Frobenius-Perron operator and highlight the potential of density estimation techniques in this area of study. © 2022, CC BY.

关键词： Galerkin methods

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Use of assisted reproductive technologies for male and female infertility and perinatal outcomes

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Fertility and Sterility 2025年

作者： Magnus, Maria C. Skåra, Karoline H. Carlsen, Ellen Ø. Gjerdevik, Miriam Ramlau-Hansen, Cecilia H. Myrskylä, Mikko Romundstad, Liv-Bente Håberg, Siri E. Centre for Fertility and Health Norwegian Institute of Public Health Oslo Norway Department of Computer Science Electrical Engineering and Mathematical Sciences Western Norway University of Applied Sciences Bergen Norway Department of Public Health Research Unit for Epidemiology Aarhus University Aarhus Denmark Max Planck Institute for Demographic Research Rostock Germany Helsinki Institute for Demography and Population Health University of Helsinki Helsinki Finland Max Planck-University of Helsinki Center for Social Inequalities in Population Health Rostock Germany Spiren Fertility Clinic Trondheim Norway Department of Global Public Health and Primary Care University of Bergen Bergen Norway

Objective: To compare adverse perinatal outcomes between naturally conceived and pregnancies conceived by assisted reproductive technologies (ARTs) according to underlying male, female, or unexplained infertility. Design: Registry-based study. Subjects: All singleton births in Norway between 2000 and 2021 recorded in the national birth registry. Exposure: We compared ART pregnancies with underlying male (N = 9,957), female (N = 10,031), mixed (N = 3,287), or unexplained (N = 7,178) infertility with naturally conceived pregnancies (N = 1,210,709). Information on underlying causes of infertility was reported from fertility clinics. Main Outcomes and Measures: We compared the birthweight and pregnancy length using robust linear regression, and the risk of pre-eclampsia, cesarean section, stillbirth, preterm birth, low birth weight, small-for-gestational age and transfer to neonatal unit using logistic regression, adjusting for parental age, maternal parity, cohabitation, country of birth, and year of delivery. Results: Pregnancy length and birthweight were lower in all ART groups compared with the naturally conceived. The shorter pregnancy length was less pronounced in ART deliveries resulting from male infertility (adjusted difference −1.24 days;95% confidence interval [CI]: −1.43 to −1.05) than in ART deliveries resulting from female infertility (adjusted difference −1.92 days;95% CI: −2.12 to −1.73). Similarly, the lower birthweight in ART deliveries was less pronounced in those resulting from male (adjusted difference −29 grams;95% CI: −39 to −18) than those resulting from female (adjusted difference −49 grams;95% CI: −59 to −39) infertility. We also observed a higher risk of most adverse perinatal outcomes in all ART groups, with the magnitude being lower for ART deliveries resulting from male infertility. Conclusion: The increased risk of adverse perinatal outcomes in pregnancies conceived by ART was less pronounced if used for male infertility than for female in

关键词： Assisted reproductive technologies infertility perinatal outcomes

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A machine learning approach for Premature Coronary Artery Disease Diagnosis according to Different Ethnicities in Iran

arXiv

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arXiv 2025年

作者： Roshanzamir, Mohamad Alizadehsani, Roohallah Zarepur, Ehsan Mohammadifard, Noushin Nouri, Fatemeh Roshanzamir, Mahdi Khosravi, Alireza Nouhi, Fereidoon Sarrafzadegan, Nizal Department of Computer Engineering Faculty of Engineering Fasa University Fasa74617-81189 Iran Biostatistics Unit Faculty of Health Deakin University Geelong Australia School of Medicine Deakin University Geelong Australia Faculty of Health School of Clinical Sciences Queensland University of Technology Brisbane Australia Isfahan Cardiovascular Research Center Cardiovascular Research Institute Isfahan University of Medical Sciences Isfahan Iran Interventional Cardiology Research Center Cardiovascular Research Institute Isfahan University of Medical Sciences Isfahan Iran Department of Electrical and Computer Engineering University of Tabriz Tabriz Iran Hypertension Research Center Cardiovascular Research Institute Isfahan University of Medical Sciences Isfahan Iran Iranian Network of Cardiovascular Research Iran Rajaie Cardiovascular Medical and Research Center Iran University of Medical Sciences Tehran Iran Faculty of Medicine School of Population and Public Health University of British Columbia Vancouver Canada

Background Premature coronary artery disease (PCAD) refers to the early onset of the disease, usually before the age of 55 for men and 65 for women. Coronary Artery Disease (CAD) develops when coronary arteries, the major blood vessels supplying the heart with blood, oxygen, and nutrients, become clogged or diseased. This is often due to many risk factors, including lifestyle and cardiometabolic ones, but few studies were done on ethnicity as one of these risk factors, especially in PCAD. Method In this study, we tested the rank of ethnicity among the major risk factors of PCAD, including age, gender, body mass index (BMI), visceral obesity presented as waist circumference (WC), diabetes mellitus (DM), high blood pressure (HBP), high low-density lipoprotein cholesterol (LDL-C), and smoking in a large national sample of patients with PCAD from different ethnicities. All patients who met the age criteria underwent coronary angiography to confirm CAD diagnosis. The weight of ethnicity was compared to the other eight features using feature weighting algorithms in PCAD diagnosis. In addition, we conducted an experiment where we ran predictive models (classification algorithms) to predict PCAD. We compared the performance of these models under two conditions: we trained the classification algorithms, including or excluding ethnicity. Result This study analyzed various factors to determine their predictive power influencing PCAD prediction. Among these factors, gender and age were the most significant predictors, with ethnicity being the third most important. The results also showed that if ethnicity is used as one of the input risk factors for classification algorithms, it can improve their efficiency. Conclusion Our results show that ethnicity ranks as an influential factor in predicting PCAD. Therefore, it needs to be addressed in the PCAD diagnostic and preventive measures. © 2025, CC BY-NC-ND.

关键词： Blood pressure

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Evaluating Offshore Electricity Market Design Considering Endogenous Infrastructure Investments: Zonal or Nodal?

IEEE Transactions on Energy Markets, Policy and Regulation

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IEEE Transactions on Energy Markets, policy and Regulation 2024年第4期2卷 476-487页

作者： Kenis, Michiel Dvorkin, Vladimir Schittekatte, Tim Bruninx, Kenneth Delarue, Erik Botterud, Audun Celestijnenlaan 300 KU Leuven Divison of Applied Mechanics and Energy Conversion LeuvenB-3001 Belgium MolB-2400 Belgium EnergyVille GenkB-3600 Belgium Massachusetts Institute of Technology Energy Initiative and Laboratory for Information and Decision Systems CambridgeMA02139 United States University of Michigan Department of Electrical Engineering and Computer Science Ann ArborMI48109 United States Energy Initiative Massachusetts Institute of Technology CambridgeMA02142 United States Faculty of Technology Policy and Management Delft University of Technology GA Delft2600 Netherlands Divison of Applied Mechanics and Energy Conversion Celestijnenlaan 300 KU Leuven LeuvenB-3001 Belgium KU Leuven Divison of Applied Mechanics and Energy Conversion Celestijnenlaan 300 LeuvenB-3001 Belgium Massachusetts Institute of Technology CambridgeMA02139 United States Argonne National Laboratory LemontIL60439 United States

policy makers are formulating offshore energy infrastructure plans, including wind turbines, electrolyzers, and HVDC transmission lines. An effective market design is crucial to guide cost-efficient investments and dispatch decisions. This paper jointly studies the impact of offshore market design choices on the investment in offshore electrolyzers and HVDC transmission capacity. We present a bilevel model that incorporates investments in offshore energy infrastructure, day-ahead market dispatch, and potential redispatch actions near real-time to ensure transmission constraints are respected. Our findings demonstrate that full nodal pricing, i.e., nodal pricing both onshore and offshore, outperforms the onshore zonal combined with offshore nodal pricing or offshore zonal layouts. While combining onshore zonal with offshore nodal pricing can be considered as a second-best option, it generally diminishes the profitability of offshore wind farms. However, if investment costs of offshore electrolyzers are relatively low, they can serve as catalysts to increase the revenues of the offshore wind farms. This study contributes to the understanding of market designs for highly interconnected offshore power systems, offering insights into the impact of congestion pricing methodologies on investment decisions. Besides, it is useful towards understanding the interaction of offshore loads like electrolyzers with financial support mechanisms for offshore wind farms. © 2024 IEEE.

关键词： Investments

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