pwc-archive/papers-with-abstracts huggingface dataset:
The statistical spread of transmission outages on a fast protection time scale based on utility data
Authors: Ian Dobson, D. Adrian Maldonado, Mihai Anitescu
Date: 2024-07-21 00:00:00

When there is a fault, the protection system automatically removes one or more transmission lines on a fast time scale of less than one minute. The outaged lines form a pattern in the transmission network. We extract these patterns from utility outage data, determine some key statistics of these patterns, and then show how to generate new patterns consistent with these statistics. The generated patterns provide a new and easily feasible way to model the overall effect of the protection system at the scale of a large transmission system. This new generative modeling of protection is expected to contribute to simulations of disturbances in large grids so that they can better quantify the risk of blackouts. Analysis of the pattern sizes suggests an index that describes how much outages spread in the transmission network at the fast timescale.
Efficient Sampling for Data-Driven Frequency Stability Constraint via Forward-Mode Automatic Differentiation
Authors: Wangkun Xu, Qian Chen, Pudong Ge, Zhongda Chu, Fei Teng
Date: 2024-07-21 00:00:00

Encoding frequency stability constraints in the operation problem is challenging due to its complex dynamics. Recently, data-driven approaches have been proposed to learn the stability criteria offline with the trained model embedded as a constraint of online optimization. However, random sampling of stationary operation points is less efficient in generating balanced stable and unstable samples. Meanwhile, the performance of such a model is strongly dependent on the quality of the training dataset. Observing this research gap, we propose a gradient-based data generation method via forward-mode automatic differentiation. In this method, the original dynamic system is augmented with new states that represent the dynamic of sensitivities of the original states, which can be solved by invoking any ODE solver for a single time. To compensate for the contradiction between the gradient of various frequency stability criteria, gradient surgery is proposed by projecting the gradient on the normal plane of the other. In the end, we demonstrate the superior performance of the proposed sampling algorithm, compared with the unrolling differentiation and finite difference. All codes are available at https://github.com/xuwkk/frequency_sample_ad.
Enhancing Microgrid Performance Prediction with Attention-based Deep Learning Models
Authors: Vinod Kumar Maddineni, Naga Babu Koganti, Praveen Damacharla
Date: 2024-07-20 00:00:00
Tasks: Deep Learning, Load Forecasting, regression

In this research, an effort is made to address microgrid systems' operational challenges, characterized by power oscillations that eventually contribute to grid instability. An integrated strategy is proposed, leveraging the strengths of convolutional and Gated Recurrent Unit (GRU) layers. This approach is aimed at effectively extracting temporal data from energy datasets to improve the precision of microgrid behavior forecasts. Additionally, an attention layer is employed to underscore significant features within the time-series data, optimizing the forecasting process. The framework is anchored by a Multi-Layer Perceptron (MLP) model, which is tasked with comprehensive load forecasting and the identification of abnormal grid behaviors. Our methodology underwent rigorous evaluation using the Micro-grid Tariff Assessment Tool dataset, with Root Mean Square Error (RMSE), Mean Absolute Error (MAE), and the coefficient of determination (r2-score) serving as the primary metrics. The approach demonstrated exemplary performance, evidenced by a MAE of 0.39, RMSE of 0.28, and an r2-score of 98.89\% in load forecasting, along with near-perfect zero state prediction accuracy (approximately 99.9\%). Significantly outperforming conventional machine learning models such as support vector regression and random forest regression, our model's streamlined architecture is particularly suitable for real-time applications, thereby facilitating more effective and reliable microgrid management.
A Holistic Optimization Framework for Energy Efficient UAV-assisted Fog Computing: Attitude Control, Trajectory Planning and Task Assignment
Authors: Shuaijun Liu, Jinqiu Du, Yaxin Zheng, Jiaying Yin, Yuhui Deng, Jingjin Wu
Date: 2024-07-20 00:00:00
Tasks: Decision Making, Trajectory Planning

Unmanned Aerial Vehicles (UAVs) have significantly enhanced fog computing by acting as both flexible computation platforms and communication mobile relays. In this paper, we propose a holistic framework that jointly optimizes the total latency and energy consumption for UAV-assisted fog computing in a three-dimensional spatial domain with varying terrain elevations and dynamic task generations. Our proposed framework considers three important and interdependent modules: attitude control, trajectory planning, and task assignment. We first establish a fuzzy proportional-integral-derivative control model to determine the UAV's attitude. Then, we propose an enhanced Ant Colony System (ACS) based algorithm, that includes a safety value and a decoupling mechanism to overcome the convergence issue in classical ACS, to compute the optimal UAV trajectory. Finally, we design an algorithm based on the Particle Swarm Optimization technique, to determine where each offloaded task should be executed. Under our proposed framework, the outcome of one module would affect the decision-making in one other, providing a holistic perspective of the system and thus leading to improved solutions. We demonstrate by extensive simulation results that our proposed framework can significantly improve the overall performance, measured by latency and energy consumption, compared to existing baseline approaches.
Inferring Ingrained Remote Information in AC Power Flows Using Neuromorphic Modality Regime
Authors: Xiaoguang Diao, Yubo Song, Subham Sahoo
Date: 2024-07-20 00:00:00
Tasks: Learning Theory, Philosophy

In this paper, we infer remote measurements such as remote voltages and currents online with change in AC power flows using spiking neural network (SNN) as grid-edge technology for efficient coordination of power electronic converters. This work unifies power and information as a means of data normalization using a multi-modal regime in the form of spikes using energy-efficient neuromorphic learning and event-driven asynchronous data collection. Firstly, we organize the synchronous real-valued measurements at each edge and translate them into asynchronous spike-based events to collect sparse data for training of SNN at each edge. Instead of relying on error-dependent supervised data-driven learning theory, we exploit the latency-driven unsupervised Hebbian learning rule to obtain modulation pulses for switching of power electronic converters that can now comprehend grid disturbances locally and adapt their operation without requiring explicit infrastructure for global coordination. Not only does this philosophy block exogenous path arrival for cyber attackers by dismissing the cyber layer, it also entails converter adaptation to system reconfiguration and parameter mismatch issues. We conclude this work by validating its energy-efficient and effective online learning performance under various scenarios in different system sizes, including modified IEEE 14-bus system and under experimental conditions.
Phase Re-service in Reinforcement Learning Traffic Signal Control
Authors: Zhiyao Zhang, George Gunter, Marcos Quinones-Grueiro, Yuhang Zhang, William Barbour, Gautam Biswas, Daniel Work
Date: 2024-07-20 00:00:00
Tasks: reinforcement-learning, Reinforcement Learning, Reinforcement Learning (RL), Traffic Signal Control

This article proposes a novel approach to traffic signal control that combines phase re-service with reinforcement learning (RL). The RL agent directly determines the duration of the next phase in a pre-defined sequence. Before the RL agent's decision is executed, we use the shock wave theory to estimate queue expansion at the designated movement allowed for re-service and decide if phase re-service is necessary. If necessary, a temporary phase re-service is inserted before the next regular phase. We formulate the RL problem as a semi-Markov decision process (SMDP) and solve it with proximal policy optimization (PPO). We conducted a series of experiments that showed significant improvements thanks to the introduction of phase re-service. Vehicle delays are reduced by up to 29.95% of the average and up to 59.21% of the standard deviation. The number of stops is reduced by 26.05% on average with 45.77% less standard deviation.
Efficient Design of a Pixelated Rectenna for WPT Applications
Authors: Rasool Keshavarz, Md. Amanath Ullah, Ali Raza, Negin Shariati
Date: 2024-07-20 00:00:00

This paper introduces a highly efficient rectenna (rectifying antenna) using a binary optimization algorithm. A novel pixelated receiving antenna has been developed to match the diode impedance of a rectifier, eliminating the need for a separate matching circuit in the rectenna's rectifier. The receiving antenna configuration is fine-tuned via a binary optimization algorithm. A rectenna is designed using optimization algorithm at 2.5 GHz with 38% RF-DC conversion efficiency when subjected to 0 dBm incident power, with an output voltage of 815mV. The proposed rectenna demonstrates versatility across various low-power WPT (wireless power transfer) applications.
Multidirectional Pixelated Cubic Antenna with Enhanced Isolation for Vehicular Applications
Authors: Md. Amanath Ullah, Rasool Keshavarz, Justin Lipman, Mehran Abolhasan, Negin Shariati
Date: 2024-07-20 00:00:00

This paper presents a pixelated cubic antenna design with enhanced isolation and diverse radiation pattern for vehicular applications. The design consists of four radiating patches to take advantage of a nearly omnidirectional radiation pattern with enhanced isolation and high gain. The antenna system with four patches has been pixelated and optimized simultaneously to achieve desired performance and high isolation at 5.4 GHz band. The antenna achieved measured isolation of more than -34 dB between antenna elements. The overall isolation improvement obtained by the antenna is about 18 dB compared to a configuration using standard patch antennas. Moreover, isolation improvement is achieved through patch pixelization without additional resonators or elements. The antenna achieved up to 6.9 dB realized gain in each direction. Additionally, the cubic antenna system is equipped with an E-shaped GPS antenna to facilitate connectivity with GPS satellite. Finally, the antenna performance has been investigated using a simulation model of the vehicle roof and roof rack. The reflection coefficient, isolation and radiation patterns of the antenna remains unaffected. The antenna prototype has been fabricated on Rogers substrate and measured to verify the simulation results. The measured results correlate well with the simulation results. The proposed antenna features low-profile, simple design for ease of manufacture, good radiation characteristics with multidirectional property and high isolation, which are well-suited to vehicular applications in different environments.
Autonomous Nonlinear Passive Transmit-Receive Switch for Compact IoT Devices: A Three-Port Agile Network
Authors: Rasool Keshavarz, Amber Abdullah, Negin Shariati
Date: 2024-07-20 00:00:00

Recent advancements in RF technologies, especially Internet of Things (IoT) devices, require compact and integrated RF circulators or transmit-receive (TR) switches for efficient resource use. Although conventional techniques are crucial in managing signal flow to prevent signal interference to sensitive receiver components, they have some drawbacks, such as limited isolation, low switching speed, complex circuitry, bulkiness, and high cost. This work presents a smart, miniaturized, nonlinear TR switch capable of operating over a wide frequency range (0.8 - 1.3 GHz), making it suitable for IoT frequency bands. The switch achieves high isolation, low insertion loss, and intelligent transitions between transmitter and receiver without requiring external control or bias pins.
Adaptive Uncertainty Quantification for Scenario-based Control Using Meta-learning of Bayesian Neural Networks
Authors: Yajie Bao, Javad Mohammadpour Velni
Date: 2024-07-19 00:00:00
Tasks: Meta-Learning, Model Predictive Control, Uncertainty Quantification

Scenario-based optimization and control has proven to be an efficient approach to account for system uncertainty. In particular, the performance of scenario-based model predictive control (MPC) schemes depends on the accuracy of uncertainty quantification. However, current learning- and scenario-based MPC (sMPC) approaches employ a single timeinvariant probabilistic model (learned offline), which may not accurately describe time-varying uncertainties. Instead, this paper presents a model-agnostic meta-learning (MAML) of Bayesian neural networks (BNN) for adaptive uncertainty quantification that would be subsequently used for adaptive-scenario-tree model predictive control design of nonlinear systems with unknown dynamics to enhance control performance. In particular, the proposed approach learns both a global BNN model and an updating law to refine the BNN model. At each time step, the updating law transforms the global BNN model into more precise local BNN models in real time. The adapted local model is then used to generate scenarios for sMPC design at each time step. A probabilistic safety certificate is incorporated in the scenario generation to ensure that the trajectories of the generated scenarios contain the real trajectory of the system and that all the scenarios adhere to the constraints with a high probability. Experiments using closed-loop simulations of a numerical example demonstrate that the proposed approach can improve the performance of scenario-based MPC compared to using only one BNN model learned offline for all time steps.
Adaptive State Observers of Linear Time-varying Descriptor Systems: A Parameter Estimation-Based Approach
Authors: Romeo Ortega, Alexey Bobtsov, Fernando Castanos, Nikolay Nikolaev
Date: 2024-07-19 00:00:00
Tasks: parameter estimation

In this paper, we apply the recently developed generalized parameter estimation-based observer design technique for state-affine systems to the practically important case of linear time-varying descriptor systems with uncertain parameters. We give simulation results of benchmark examples that illustrate the performance of the proposed adaptive observer.
Trustworthy V2G scheduling and energy trading: A blockchain-based framework
Authors: Yunwang Chen, Xiang Lei, Songyan Niu, Linni Jian
Date: 2024-07-19 00:00:00
Tasks: Decision Making, energy trading, Scheduling

The rapid growth of electric vehicles (EVs) and the deployment of vehicle-to-grid (V2G) technology pose significant challenges for distributed power grids, particularly in fostering trust and ensuring effective coordination among stakeholders. Establishing a trustworthy V2G operation environment is crucial for enabling large-scale EV user participation and realizing V2G potential in real-world applications. In this paper, an integrated scheduling and trading framework is developed to conduct transparent and efficacious coordination in V2G operations. In blockchain implementation, a cyber-physical blockchain architecture is proposed to enhance transaction efficiency and scalability by leveraging smart charging points (SCPs) for rapid transaction validation through a fast-path practical byzantine fault tolerance (fast-path PBFT) consensus mechanism. From the energy dispatching perspective, a game-theoretical pricing strategy is employed and smart contracts are utilized for autonomous decision-making between EVs and operators, aiming to optimize the trading process and maximize economic benefits. Numerical evaluation of blockchain consensus shows the effect of the fast-path PBFT consensus in improving systems scalability with a balanced trade-off in robustness. A case study, utilizing real-world data from the Southern University of Science and Technology (SUSTech), demonstrates significant reductions in EV charging costs and the framework potential to support auxiliary grid services.
Real-time Estimation of Bound Water Concentration during Lyophilization with Temperature-based State Observers
Authors: Prakitr Srisuma, George Barbastathis, Richard Braatz
Date: 2024-07-18 00:00:00

Lyophilization (aka freeze drying) has been shown to provide long-term stability for many crucial biotherapeutics, e.g., mRNA vaccines for COVID-19, allowing for higher storage temperature. The final stage of lyophilization, namely secondary drying, entails bound water removal via desorption, in which accurate prediction of bound water concentration is vital to ensuring the quality of the lyophilized product. This article proposes a novel technique for real-time estimation of the residual moisture during secondary drying in lyophilization. A state observer is employed, which combines temperature measurement and mechanistic understanding of heat transfer and desorption kinetics, without requiring any online concentration measurement. Results from both simulations and experimental data show that the observer can accurately estimate the concentration of bound water in real time for all possible concentration levels, operating conditions, and measurement noise. This framework can also be applied for monitoring and control of the residual moisture in other desorption-related processes.
SOC-Boundary and Battery Aging Aware Hierarchical Coordination of Multiple EV Aggregates Among Multi-stakeholders with Multi-Agent Constrained Deep Reinforcement Learning
Authors: Xin Chen
Date: 2024-07-14 00:00:00
Tasks: Deep Reinforcement Learning, Scheduling

As electric vehicles (EV) become more prevalent and advances in electric vehicle electronics continue, vehicle-to-grid (V2G) techniques and large-scale scheduling strategies are increasingly important to promote renewable energy utilization and enhance the stability of the power grid. This study proposes a hierarchical multistakeholder V2G coordination strategy based on safe multi-agent constrained deep reinforcement learning (MCDRL) and the Proof-of-Stake algorithm to optimize benefits for all stakeholders, including the distribution system operator (DSO), electric vehicle aggregators (EVAs) and EV users. For DSO, the strategy addresses load fluctuations and the integration of renewable energy. For EVAs, energy constraints and charging costs are considered. The three critical parameters of battery conditioning, state of charge (SOC), state of power (SOP), and state of health (SOH), are crucial to the participation of EVs in V2G. Hierarchical multi-stakeholder V2G coordination significantly enhances the integration of renewable energy, mitigates load fluctuations, meets the energy demands of the EVAs, and reduces charging costs and battery degradation simultaneously.
Estimating Probability Densities with Transformer and Denoising Diffusion
Authors: Henry W. Leung, Jo Bovy, Joshua S. Speagle
Date: 2024-07-22 00:00:00
Tasks: Denoising, Density Estimation

Transformers are often the go-to architecture to build foundation models that ingest a large amount of training data. But these models do not estimate the probability density distribution when trained on regression problems, yet obtaining full probabilistic outputs is crucial to many fields of science, where the probability distribution of the answer can be non-Gaussian and multimodal. In this work, we demonstrate that training a probabilistic model using a denoising diffusion head on top of the Transformer provides reasonable probability density estimation even for high-dimensional inputs. The combined Transformer+Denoising Diffusion model allows conditioning the output probability density on arbitrary combinations of inputs and it is thus a highly flexible density function emulator of all possible input/output combinations. We illustrate our Transformer+Denoising Diffusion model by training it on a large dataset of astronomical observations and measured labels of stars within our Galaxy and we apply it to a variety of inference tasks to show that the model can infer labels accurately with reasonable distributions.
Text-to-Battery Recipe: A language modeling-based protocol for automatic battery recipe extraction and retrieval
Authors: Daeun Lee, Jaewoong Choi, Hiroshi Mizuseki, Byungju Lee
Date: 2024-07-22 00:00:00
Tasks: Information Retrieval, Language Modeling, Language Modelling, named-entity-recognition, Named Entity Recognition, Topic Models

Recent studies have increasingly applied natural language processing (NLP) to automatically extract experimental research data from the extensive battery materials literature. Despite the complex process involved in battery manufacturing -- from material synthesis to cell assembly -- there has been no comprehensive study systematically organizing this information. In response, we propose a language modeling-based protocol, Text-to-Battery Recipe (T2BR), for the automatic extraction of end-to-end battery recipes, validated using a case study on batteries containing LiFePO4 cathode material. We report machine learning-based paper filtering models, screening 2,174 relevant papers from the keyword-based search results, and unsupervised topic models to identify 2,876 paragraphs related to cathode synthesis and 2,958 paragraphs related to cell assembly. Then, focusing on the two topics, two deep learning-based named entity recognition models are developed to extract a total of 30 entities -- including precursors, active materials, and synthesis methods -- achieving F1 scores of 88.18% and 94.61%. The accurate extraction of entities enables the systematic generation of 165 end-toend recipes of LiFePO4 batteries. Our protocol and results offer valuable insights into specific trends, such as associations between precursor materials and synthesis methods, or combinations between different precursor materials. We anticipate that our findings will serve as a foundational knowledge base for facilitating battery-recipe information retrieval. The proposed protocol will significantly accelerate the review of battery material literature and catalyze innovations in battery design and development.
Voltage mapping in subcellular nanodomains using electro-diffusion modeling
Authors: Frédéric Paquin-Lefebvre, David Holcman
Date: 2024-07-22 00:00:00

Voltage distribution in sub-cellular micro-domains such as neuronal synapses, small protrusions or dendritic spines regulates the opening and closing of ionic channels, energy production and thus cellular homeostasis and excitability. Yet how voltage changes at such a small scale in vivo remains challenging due to the experimental diffraction limit, large signal fluctuations and the still limited resolution of fast voltage indicators. Here, we study the voltage distribution in nano-compartments using a computational approach based on the Poisson-Nernst-Planck equations for the electro-diffusion motion of ions, where inward and outward fluxes are generated between channels. We report a current-voltage (I-V) logarithmic relationship generalizing Nernst law that reveals how the local membrane curvature modulates the voltage. We further find that an influx current penetrating a cellular electrolyte can lead to perturbations from tens to hundreds of nanometers deep depending on the local channels organization. Finally, we show that the neck resistance of dendritic spines can be completely shunted by the transporters located on the head boundary, facilitating ionic flow. To conclude, we propose that voltage is regulated at a subcellular level by channels organization, membrane curvature and narrow passages.