Current Organizations / Institutes

The organizations/institutes from the scholar's latest article

Previous Organizations / Institutes

The organizations / institutes from the scholar's other articles in the past ten years


Miriam Akemi Manabe Capretz has a total of 98 co-authors. Here are the top co-authors by number of shared publications:


Latest Publications

  • Open Access

    A multi-level traffic analysis framework for software-defined networks using hierarchical aggregation and topological mapping

    by Wander Queiroz, Jose Eduardo Santarem Segundo, Mario A.R. Dantas, Miriam A.M. Capretz

  • Open Access

    Can large language models predict solar irradiance in the long term?

    by Thales W. Cabral, Gustavo Fraidenraich, Miriam A.M. Capretz

  • Open Access

    Prospect utility with hyperbolic tangent function

    by Patrick Adjei, Santiago Gomez-Rosero, Miriam A.M. Capretz


  • Open Access

    Safe Reinforcement Learning for Arm Manipulation with Constrained Markov Decision Process

    by Patrick Adjei, Norman Tasfi, Santiago Gomez-Rosero, Miriam A. M. Capretz

    In the world of human–robot coexistence, ensuring safe interactions is crucial. Traditional logic-based methods often lack the intuition required for robots, particularly in complex environments where these methods fail to account for all possible scenarios. Reinforcement learning has shown promise in robotics due to its superior adaptability over traditional logic. However, the exploratory nature of reinforcement learning can jeopardize safety. This paper addresses the challenges in planning trajectories for robotic arm manipulators in dynamic environments. In addition, this paper highlights the pitfalls of multiple reward compositions that are susceptible to reward hacking. A novel method with a simplified reward and constraint formulation is proposed. This enables the robot arm to avoid a nonstationary obstacle that never resets, enhancing operational safety. The proposed approach combines scalarized expected returns with a constrained Markov decision process through a Lagrange multiplier, resulting in better performance. The scalarization component uses the indicator cost function value, directly sampled from the replay buffer, as an additional scaling factor. This method is particularly effective in dynamic environments where conditions change continually, as opposed to approaches relying solely on the expected cost scaled by a Lagrange multiplier.


  • Open Access

    Toward Prediction of Energy Consumption Peaks and Timestamping in Commercial Supermarkets Using Deep Learning

    by Mengchen Zhao, Santiago Gomez-Rosero, Hooman Nouraei, Craig Zych, Miriam A. M. Capretz, Ayan Sadhu

    Building energy consumption takes up over 30% of global final energy use and 26% of global energy-related emissions. In addition, building operations represent nearly 55% of global electricity consumption. The management of peak demand plays a crucial role in optimizing building electricity usage, consequently leading to a reduction in carbon footprint. Accurately forecasting peak demand in commercial buildings provides benefits to both the suppliers and consumers by enhancing efficiency in electricity production and minimizing energy waste. Precise predictions of energy peaks enable the implementation of proactive peak-shaving strategies, the effective scheduling of battery response, and an enhancement of smart grid management. The current research on peak demand for commercial buildings has shown a gap in addressing timestamps for peak consumption incidents. To bridge the gap, an Energy Peaks and Timestamping Prediction (EPTP) framework is proposed to not only identify the energy peaks, but to also accurately predict the timestamps associated with their occurrences. In this EPTP framework, energy consumption prediction is performed with a long short-term memory network followed by the timestamp prediction using a multilayer perceptron network. The proposed framework was validated through experiments utilizing real-world commercial supermarket data. This evaluation was performed in comparison to the commonly used block maxima approach for indexing. The 2-h hit rate saw an improvement from 21% when employing the block maxima approach to 52.6% with the proposed EPTP framework for the hourly resolution. Similarly, the hit rate increased from 65.3% to 86% for the 15-min resolution. In addition, the average minute deviation decreased from 120 min with the block maxima approach to 62 min with the proposed EPTP framework with high-resolution data. The framework demonstrates satisfactory results when applied to high-resolution data obtained from real-world commercial supermarket energy consumption.


  • Open Access

    LoRaCELL-Driven IoT Smart Lighting Systems: Sustainability in Urban Infrastructure

    by Iago Z. Biundini, Milena F. Pinto, Leonardo M. Honório, Miriam A. M. Capretz, Amanda O. Timotheo, Mario A. R. Dantas, Priscilla C. Villela

    In recent years, the rate of urbanization has increased enormously, precipitating an escalating demand for improved services and applications in urban areas to improve the quality of life. In the Internet of Things (IoT)era, cities are transforming into smart urban centers. These cities incorporate connected devices, such as intelligent public lighting systems, to enhance their urban infrastructure. Therefore, this work explores the transformative potential of an IoT-enabled smart lighting system in urban environments, emphasizing its essential role in enhancing safety, economy, and sustainability. In this sense, LoRaCELL (Long-Range Cell) is introduced. LoRaCELL is an innovative system that utilizes edge devices for data collection, such as light intensity, humidity, temperature, air quality, solar ultraviolet radiation, ammeter, and voltmeter. It stands as a pioneering solution for intelligent public lighting systems, contributing to advancing IoT-driven urban development. The outcomes showed that the proposed system could successfully synchronize the devices with each other and send IoT sensing data at a low cost compared to traditional technologies such as LoRaWAN.


  • Multi-Factor Edge-Weighting with Reinforcement Learning for Load Balancing of Electric Vehicle Charging Stations

    by Lucas Hartman, Santiago Gomez-Rosero, Patrick Adjei, Miriam A. M. Capretz

    The number of electric vehicle (EV) owners continues to grow at a rate that makes it increasingly difficult to avoid overloading the capacity of charging stations. Existing solutions to balance this load primarily focus on solving parts of the problem and fail to consider a more holistic approach that can solve the issue of balancing the load across multiple stations by handling EV routing. This paper proposes a novel solution that routes EVs while considering both travel times and peak loads at charging stations. The approach integrates a reinforcement learning algorithm with a path-finding algorithm and a custom-built simulation environment. Compared with baseline methods, the solution showed improved performance in minimizing peak power loads across charging stations while increasing individual trip duration by less than 5%. This approach has the potential to significantly improve the efficiency of EV charging by reducing peak loads at charging stations.

  • Open Access

    Health Prognostics Classification with Autoencoders for Predictive Maintenance of HVAC Systems

    by Ruiqi Tian, Santiago Gomez-Rosero, Miriam A. M. Capretz

    Buildings’ heating, ventilation, and air-conditioning (HVAC) systems account for significant global energy use. Proper maintenance can minimize their environmental footprint and enhance the quality of the indoor environment. The adoption of Internet of Things (IoT) sensors integrated into HVAC systems has paved the way for predictive maintenance (PdM) grounded in real-time operational metrics. However, HVAC systems without such sensors cannot leverage the advantages of current data-driven PdM techniques. This work introduces a novel data-driven framework, the health prognostics classification with autoencoders (HPC-AE), designed specifically for PdM. It utilizes solely HVAC power consumption and outside temperature readings for its operations, both of which are readily obtainable. The primary objective of the HPC-AE framework is to facilitate PdM through a health prognostic approach. The HPC-AE framework utilizes an autoencoder for feature enrichment and then applies an artificial neural network to classify the daily health condition of an HVAC system. A multi-objective evaluation metric is employed to ensure optimal performance of the autoencoder within this framework. This metric evaluates the autoencoder’s proficiency in reducing reconstruction discrepancies in standard data conditions and its capability to differentiate between standard and degraded data scenarios. The HPC-AE framework is validated in two HVAC fault scenarios, including a clogged air filter and air duct leakage. The experimental results show that compared to methods used in similar studies, HPC-AE exhibits a 5.7% and 2.1% increase in the F1 score for the clogged air filter and duct leakage scenarios.


  • Top Cited Papers
    Open Access

    Toward Smart-Building Digital Twins: BIM and IoT Data Integration

    by Dagimawi D. Eneyew, Miriam A. M. Capretz, Girma T. Bitsuamlak

    Smart building digital twins aim to virtually replicate the static and dynamic building characteristics through real-time connectivity between the virtual and physical counterparts. The virtual replica of the building can then be leveraged to monitor the current state, predict the future state, and take proactive measures to ensure optimal operation. Despite its potential, smart building digital twin research is at an early stage compared to manufacturing and aerospace fields. One of the major impediments to adopting digital twin technology in smart buildings is the lack of interoperability, primarily between Building Information Modeling (BIM) and Internet of Things (IoT) data sources. Consequently, this paper presents a novel multi-layer digital twin architecture for smart buildings called BIM-IoT Data Integration (BIM-IoTDI) to enable semantic interoperability among smart building digital twin applications. A detailed framework is presented based on the newly developed architecture, introducing an ontology-based query mediation method that provides integrated data access. The feasibility of the BIM-IoTDI architecture and framework is demonstrated using a case study building and real-time monitoring application. Furthermore, the performance of the new query mediation method is evaluated and compared to an existing BIM-IoT data integration approach. According to the evaluation results, the BIM-IoTDI architecture and framework are better suited to supporting the envisioned smart building digital twin capabilities.