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Publicações

2024

Efficient Runtime Firmware Update Mechanism for LoRaWAN Class A Devices

Autores
Neves, BP; Valente, A; Santos, VDN;

Publicação
ENG

Abstract
This paper presents an efficient and secure method for updating firmware in IoT devices using LoRaWAN network resources and communication protocols. The proposed method involves dividing the firmware into fragments, storing them in the application server's database, and transmitting them to remote IoT devices via downlink messages, without necessitating any changes to the device's class. This approach can be replicated across any IoT LoRaWAN device, offering a robust and scalable solution for large-scale firmware updates while ensuring data security and integrity. The proposed method significantly reduces the downtime of IoT devices and enhances the energy efficiency of the update process. The method was validated by updating a block in the program memory, associated to a specific functionality of the IoT end device. The associated Intel Hex file was segmented into 17 LoRaWAN downlink frames with an average size of 46 bytes. Upon receiving the complete firmware update, the microcontroller employs self-programming techniques that restrict the update process to specific rows of the program memory, avoiding interruptions or reboots. The update process was successfully completed in 51.33 ms, resulting in a downtime of 16.88 ms. This method demonstrates improved energy efficiency compared to existing solutions while preserving the communication network's capacity, making it an adequate solution for remote devices in LoRaWAN networks.

2024

Variation in monitoring: Glucose measurement in the ICU as a case study to preempt spurious correlations

Autores
Teotia, K; Jia, YR; Woite, NL; Celi, LA; Matos, J; Struja, T;

Publicação
JOURNAL OF BIOMEDICAL INFORMATICS

Abstract
Objective: Health inequities can be influenced by demographic factors such as race and ethnicity, proficiency in English, and biological sex. Disparities may manifest as differential likelihood of testing which correlates directly with the likelihood of an intervention to address an abnormal finding. Our retrospective observational study evaluated the presence of variation in glucose measurements in the Intensive Care Unit (ICU). Methods: Using the MIMIC-IV database (2008-2019), a single -center, academic referral hospital in Boston (USA), we identified adult patients meeting sepsis-3 criteria. Exclusion criteria were diabetic ketoacidosis, ICU length of stay under 1 day, and unknown race or ethnicity. We performed a logistic regression analysis to assess differential likelihoods of glucose measurements on day 1. A negative binomial regression was fitted to assess the frequency of subsequent glucose readings. Analyses were adjusted for relevant clinical confounders, and performed across three disparity proxy axes: race and ethnicity, sex, and English proficiency. Results: We studied 24,927 patients, of which 19.5% represented racial and ethnic minority groups, 42.4% were female, and 9.8% had limited English proficiency. No significant differences were found for glucose measurement on day 1 in the ICU. This pattern was consistent irrespective of the axis of analysis, i.e. race and ethnicity, sex, or English proficiency. Conversely, subsequent measurement frequency revealed potential disparities. Specifically, males (incidence rate ratio (IRR) 1.06, 95% confidence interval (CI) 1.01 - 1.21), patients who identify themselves as Hispanic (IRR 1.11, 95% CI 1.01 - 1.21), or Black (IRR 1.06, 95% CI 1.01 - 1.12), and patients being English proficient (IRR 1.08, 95% CI 1.01 - 1.15) had higher chances of subsequent glucose readings. Conclusion: We found disparities in ICU glucose measurements among patients with sepsis, albeit the magnitude was small. Variation in disease monitoring is a source of data bias that may lead to spurious correlations when modeling health data.

2024

Generative AI for Test Driven Development: Preliminary Results

Autores
Mock, M; Melegati, J; Russo, B;

Publicação
XP Workshops

Abstract
AbstractTest Driven Development (TDD) is one of the major practices of Extreme Programming for which incremental testing and refactoring trigger the code development. TDD has limited adoption in the industry, as it requires more code to be developed and experienced developers. Generative AI (GenAI) may reduce the extra effort imposed by TDD. In this work, we introduce an approach to automatize TDD by embracing GenAI either in a collaborative interaction pattern in which developers create tests and supervise the AI generation during each iteration or a fully-automated pattern in which developers only supervise the AI generation at the end of the iterations. We run an exploratory experiment with ChatGPT in which the interaction patterns are compared with the non-AI TDD regarding test and code quality and development speed. Overall, we found that, for our experiment and settings, GenAI can be efficiently used in TDD, but it requires supervision of the quality of the produced code. In some cases, it can even mislead non-expert developers and propose solutions just for the sake of the query.

2024

Predicting Retail Store Transaction Patterns: A Comparison of ARIMA and Machine Learning Models

Autores
Vaz, CB; Sena, I; Braga, AC; Novais, P; Fernandes, FP; Lima, J; Pereira, AI;

Publicação
OPTIMIZATION, LEARNING ALGORITHMS AND APPLICATIONS, OL2A 2024, PT I

Abstract
Retail transactions represent sales of consumer goods, or final goods, by consumer companies. This sector faces security challenges due to the hustle and bustle of sales, affecting employees' workload. In this context, it is essential to estimate the number of customers who will appear in the store daily so that companies can dynamically adjust employee schedules, aligning workforce capacity with expected demand. This can be achieved by forecasting transactions using past observations and forecasting algorithms. This study aims to compare the ARIMA time series algorithm with several Machine Learning algorithms to predict the number of daily transactions in different store patterns, considering data variability. The study identifies four typical store patterns based on these criteria using daily transaction data between 2019 and 2023 from all retail stores of the leading company in Portugal. Due to data variability and the results obtained, the algorithm that presents the most minor errors in predicting daily transactions is selected for each store. This study's ultimate goal is to fill the gap in forecasting daily customer transactions and present a suitable forecasting model to mitigate risks associated with transactions in retail stores.

2024

UAV-Assisted Navigation for Insect Traps in Olive Groves

Autores
Berger, GS; Bonzatto, L Jr; Pinto, MF; Júnior, AO; Mendes, J; da Silva, YMR; Pereira, AI; Valente, A; Lima, J;

Publicação
ROBOT 2023: SIXTH IBERIAN ROBOTICS CONFERENCE, VOL 2

Abstract
Unmanned Aerial Vehicles (UAVs) have emerged as valuable tools in precision agriculture due to their ability to provide timely and detailed information over large agricultural areas. In this sense, this work aims to evaluate the semi-autonomous navigation capacity of a multirotor UAV when applied in the field of precision agriculture. For this, a small aircraft is used to identify and track a set of fiducial markers (Ar Track Alvar) in an environment that simulates inspections of insect traps in olive groves. The purpose of this marker is to provide a visual reference point for the drone's navigation system. Once the Ar Track Alvar marker is detected, the robot will receive navigation information based on the marker's position to approach the specific trap. The experimental setup evaluated the computer vision algorithm applied to the UAV to make it recognize the Ar Track Alvar marker and then reach the trap efficiently. Experimental tests were conducted in a indoor and outdoor environment using DJI Tello. The results demonstrated the feasibility of applying these fiducial markers as a solution for the UAV's navigation in this proposed scenario.

2024

The moderator effect of balance of power on the relationships between the adoption of digital technologies in supply chain management processes and innovation performance in SMEs

Autores
Zimmermann, R; Soares, A; Roca, JB;

Publicação
INDUSTRIAL MARKETING MANAGEMENT

Abstract
Managing supply chain (SC) relationships to deal with challenges posed by contemporary social and business environments is a difficult task that can be facilitated with the use of digital technologies. The growing complexity of supply chains, characterized by over-dependencies on geographically dispersed partners across different regions, increases risks related to managing these relationships and highlights the importance of collaboration and balancing the power dynamics between SC partners. Previous studies have shown that small and medium enterprises (SMEs) can be considered the weakest link in terms of digitization and balance of power. This article aims to analyse how buyer-seller power relations moderate the relationship between the adoption of digital technologies in supply chain management (SCM) processes and innovation performance in the context of SMEs. Data were collected from manufacturing SMEs operating in Portugal. The results support the assumption that the use of digital technologies in processes related to SCM has a positive effect on SMEs innovation performance. The results also suggest that non-mediated power and reward-mediated positively moderate the relationship between the adoption of digital technologies and innovation performance, while the impact of coercive-mediated power was not confirmed. The article contributes to theory and practice by advancing the literature and guiding managers in the challenging task of carrying out digital transformation initiatives, considering their relationship with the power dynamics in the complex context of SMEs.

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