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


Francisco Cercas has a total of 101 co-authors. Here are the top co-authors by number of shared publications:


Latest Publications

  • Open Access

    Can ChatGPT Support Clinical Coding Using the ICD-10-CM/PCS?

    by Bernardo Nascimento Teixeira, Ana Leitão, Generosa Nascimento, Adalberto Campos-Fernandes, Francisco Cercas

    Introduction: With the growing development and adoption of artificial intelligence in healthcare and across other sectors of society, various user-friendly and engaging tools to support research have emerged, such as chatbots, notably ChatGPT. Objective: To investigate the performance of ChatGPT as an assistant to medical coders using the ICD-10-CM/PCS. Methodology: We conducted a prospective exploratory study between 2023 and 2024 over 6 months. A total of 150 clinical cases coded using the ICD-10-CM/PCS, extracted from technical coding books, were systematically randomized. All cases were translated into Portuguese (the native language of the authors) and English (the native language of the ICD-10-CM/PCS). These clinical cases varied in complexity levels regarding the quantity of diagnoses and procedures, as well as the nature of the clinical information. Each case was input into the 2023 ChatGPT free version. The coding obtained from ChatGPT was analyzed by a senior medical auditor/coder and compared with the expected results. Results: Regarding the correct codes, ChatGPT’s performance was higher by approximately 29 percentage points between diagnoses and procedures, with greater proficiency in diagnostic codes. The accuracy rate for codes was similar across languages, with rates of 31.0% and 31.9%. The error rate in procedure codes was substantially higher than that in diagnostic codes by almost four times. For missing information, a higher incidence was observed in diagnoses compared to procedures of slightly more than double the comparative rates. Additionally, there was a statistically significant excess of codes not related to clinical information, which was higher in procedures and nearly the same value in both languages under study. Conclusion: Given the ease of access to these tools, this investigation serves as an awareness factor, demonstrating that ChatGPT can assist the medical coder in directed research. However, it does not replace their technical validation in this process. Therefore, further developments of this tool are necessary to increase the quality and reliability of the results.


  • Wearable Tag for Indoor Localization in the Context of Ambient Assisted Living

    by Mariana Jacob Rodrigues, Octavian Postolache, Francisco Cercas


  • The Influence of Stress Noise and Music Stimulation on the Autonomous Nervous System

    by Mariana C. Jacob Rodrigues, Octavian Postolache, Francisco Cercas

    Music sound has shown to affect brain function and cardiac activity. Based on this premise, this study examines the effects of sound stimulation, such as music and stress noise, on the balance of the autonomous nervous system (ANS). To monitor such effects, physiological data was collected from a group of volunteers to analyze pulse rate variability (PRV), as well as electrodermal activity (EDA). The final goals of this study are supported by the possibility of automatically integrating musical stimuli into a smart environment to potentially lower individual’s stress levels, as well as to improve their well-being. To accomplish this objective, this research involved three different phases. The first was based on the development of a biomedical wearable sensor for measuring PRV and its validation using a reference sensing system. Good correlation results were obtained between both devices. The second consisted of a preliminary study of the effects of ambient, classic and metal music on PRV. Significant variations of PRV were measured between the three music genres. Considering the obtained results in the previous phase and overcoming the limitations presented in it, the third phase was based on a more in-depth study of the effects of musical stimuli and noise stress, through PRV analysis and the measurement of galvanic skin response (GSR). The obtained results suggested that noise stress contributes to the increasing of sympathetic activity. In contrast, ambient music proved to be very effective in increasing parasympathetic activity and stabilizing comfort levels.


  • Open Access

    An Optimized Planning Tool for Microwave Terrestrial and Satellite Link Design

    by Eduardo Ferreira, Pedro Sebastião, Francisco Cercas, Carlos Sá Costa, Américo Correia

    Today, the internet is fundamental to social inclusion. There are many people that live in remote areas, and the only way to supply internet services is through the use of microwave terrestrial and satellite systems. Thus, it is important to have efficient tools to design and optimize these systems. In this paper, a tool with the objective to shorten the time spent in the design process of microwave terrestrial and satellite point-to-point links is presented. This tool can be applied in academia by engineering students, providing an extended analysis of many sections of a link project design, as well as in professional practice by telecommunication engineering departments, presenting a concise step-by-step interactive design process. This tool uses three-dimensional world visualization, with the Cesium Application Programming Interface (API), to display and analyze site-specific characteristics that can disrupt the link’s quality of service (QoS). Using this visualization, two ray-tracing algorithms were developed to analyze signal diffraction and reflection mainly throughout terrestrial links. Using this new algorithm, an innovative process for signal diffraction and reflection calculations was created. Using updated standards provided by the International Telecommunication Union Radiocommunication Sector (ITU-R), the characteristics of the defined simulated links could be predicted, thus providing the user with the metrics of signal quality and system link budget.


  • Open Access

    IoT-Based Systems for Soil Nutrients Assessment in Horticulture

    by Stefan Postolache, Pedro Sebastião, Vitor Viegas, Octavian Postolache, Francisco Cercas

    Soil nutrients assessment has great importance in horticulture. Implementation of an information system for horticulture faces many challenges: (i) great spatial variability within farms (e.g., hilly topography); (ii) different soil properties (e.g., different water holding capacity, different content in sand, sit, clay, and soil organic matter, different pH, and different permeability) for different cultivated plants; (iii) different soil nutrient uptake by different cultivated plants; (iv) small size of monoculture; and (v) great variety of farm components, agroecological zone, and socio-economic factors. Advances in information and communication technologies enable creation of low cost, efficient information systems that would improve resources management and increase productivity and sustainability of horticultural farms. We present an information system based on different sensing capability, Internet of Things, and mobile application for horticultural farms. An overview on different techniques and technologies for soil fertility evaluation is also presented. The results obtained in a botanical garden that simulates the diversity of environment and plant diversity of a horticultural farm are discussed considering the challenges identified in the literature and field research. The study provides a theoretical basis and technical support for the development of technologies that enable horticultural farmers to improve resources management.


  • Unobtrusive Cardio-Respiratory Assessment for Different Indoor Environmental Conditions

    by Mariana C. Jacob Rodrigues, Octavian Postolache, Francisco Cercas

    The achievement of a healthy indoor environment - an indispensable requirement for human well-being - relies on the establishment of good air quality conditions and thermal comfort levels. This study addresses the development of a healthcare-focused Internet of Things (IoT) system for cardiac assessment using photoplethysmography (PPG) and ballistocardiography (BCG) that can be applied in any indoor environment. Results from its experimental application include the analysis of heart rate variability (HRV) and respiratory status from a group of young adults under different thermal conditions and relative humidity levels. The final goal was to investigate the effects of a short-term exposure of different air temperature and humidity conditions on human thermal comfort, based on the analysis of the autonomic nervous system (ANS) activity. The experiment took place in a regular and non-isothermal office environment. Simulations based on computational fluid dynamics (CFD) were conducted to estimate heat distribution and select the optimal locations for the environmental sensor nodes’s placement. Results indicated that an activation of the parasympathetic system was more notable in short-term exposures to environments with different air temperatures (24°C – 30°C) than with different levels of relative humidity (50% - 70%). Changes in ambient air temperature led to the activation of thermal regulatory reflexes and thermal discomfort, perceived by an increase of the ratio of low frequency to high frequency (LF/HF) at higher air temperature exposures. Additionally, HRV parameters were used to train machine learning models on predicting if the user is at a thermally comfortable environment or discomfortable environment (hot or humid), having achieved an 87% average accuracy.


  • Open Access

    Two methods for Jamming Identification in UAVs Networks using New Synthetic Dataset

    by Joseanne Viana, Hamed Farkhari, Luis Miguel Campos, Pedro Sebastiao, Francisco Cercas, Luis Bernardo, Rui Dinis

    Unmanned aerial vehicle (UAV) systems are vulnerable to jamming from self-interested users who utilize radio devices for their benefits during UAV transmissions. The vulnerability occurs due to the open nature of air-to-ground (A2G) wireless communication networks, which may enable network-wide attacks. This paper presents two strategies to identify Jammers in UAV networks. The first strategy is based on time series approaches for anomaly detection where the signal available in resource blocks are decomposed statistically to find trend, seasonality, and residues, while the second is based on newly designed deep networks. The joined technique is suitable for UAVs because the statistical model does not require heavy computation processing but is limited in generalizing possible attack's identification. On the other hand, the deep network can classify attacks accurately but requires more resources. The simulation considers the location and power of the jamming attacks and the UAV position related to the base station. The statistical method technique made it feasible to identify 84.38 % of attacks when the attacker was at 30 m from the UAV. Furthermore, the Deep network's accuracy was approximately 99.99 % for jamming powers greater than two and jammer distances less than 200 meters.

  • Open Access

    Increasing Reliability on UAV Fading Scenarios

    by Joseanne Viana, Joao Madeira, Nidhi, Pedro Sebastiao, Francisco Cercas, Albena Mihovska, Rui Dinis

    Unmanned aerial vehicles (UAVs) are the next technology to be incorporated into a telecommunications network to improve command and control on a large scale in both line-of-sight (LOS) and non-line-of-sight (NLOS) conditions. However, there is still room for improvement in terms of reliability. This paper investigates Constant Packet Combining (CPC) and Adaptive Packet Combining (APC) techniques applied to Unmanned Aerial Vehicle (UAV) communication in the presence of large-scale fading, where the channels are subject to sudden degradation for long periods due to obstructions. We use Single Carrier (SC) Frequency Domain Equalization (FDE) combined with the Iterative Block Decision-Feedback Equalizer (IB-DFE) to handle command and control messages mapped for UAV use cases. We present closed-form equations for the equalization design as well as the performance parameters such as Bit Error Rate (BER), the Packet Error Rate (PER), the throughput, the retransmissions amount, the goodput (the transmission rate without the retransmissions quantity), and the outage probability. Then, we analyze the system performance using correlated, independent, and equal channels. There is a trade-off between the overall available power, throughput, and reliability. For instance, more retransmissions result in higher reliability, power consumption and lower goodputs (effective data rates). CPC validates the transmission system and confirms the improvement of BER and PER parameters without energy efficiency optimization. APC is appealing because it can reduce the number of retransmissions for all channels used with the advantage of meeting energy efficiency requirements by adapting the overall power to the scenario experienced by the UAV.


  • Open Access

    Low-Complexity Channel Codes for Reliable Molecular Communication via Diffusion

    by Sofia Figueiredo, Nuno Souto, Francisco Cercas

    It is envisioned that healthcare systems of the future will be revolutionized with the development and integration of body-centric networks into future generations of communication systems, giving rise to the so-called “Internet of Bio-nano things”. Molecular communications (MC) emerge as the most promising way of transmitting information for in-body communications. One of the biggest challenges is how to minimize the effects of environmental noise and reduce the inter-symbol interference (ISI) which in an MC via diffusion scenario can be very high. To address this problem, channel coding is one of the most promising techniques. In this paper, we study the effects of different channel codes integrated into MC systems. We provide a study of Tomlinson, Cercas, Hughes (TCH) codes as a new attractive approach for the MC environment due to the codeword properties which enable simplified detection. Simulation results show that TCH codes are more effective for these scenarios when compared to other existing alternatives, without introducing too much complexity or processing power into the system. Furthermore, an experimental proof-of-concept macroscale test bed is described, which uses pH as the information carrier, and which demonstrates that the proposed TCH codes can improve the reliability in this type of communication channel.