https://repositorio.unifei.edu.br/jspui/handle/123456789/87 2026-07-06T17:40:45Z https://repositorio.unifei.edu.br/jspui/handle/123456789/3173 Aquisição e validação de sinal de ruído eletroquímico Corrosion is a global problem, which implies costs in industrialized countries of up to 4.5% of GDP, with either economic, but also social and environmental impacts. In the case of Brazil, the waste of water supply networks due to leaks loss is quite significant and much of it is caused by network degradation, indicating that corrosion control should be promoted whenever possible. This study proposes a corrosion monitoring system, in system subject to the use of inhibitor, with the approach of passive technique for monitoring corrosion by electrochemical noise (EN), in which the classification of events in a corrosion sensor by EN is part of methodological study for structural integrity (or “health”) monitoring system (SHM). Due to very dynamic and stochastic nature of the signal, this study and analysis of EN measurements (ENM) considers numerical and graphic characteristics of two corrosion systems both in saline aqueous solution: carbon steel and stainless steel. These experiments are repeated for accumulating data, which allow the generation of several graphs in time and frequency domains, from which at least one characteristic is extracted, which has a good correlation with data from corrosion processes. Then, based on a supervised machine learning system, the training data allows the model to be calibrated. From the test data, the correctness rate of the model above 50% is verified. Dissertação 2022-02-17T00:00:00Z https://repositorio.unifei.edu.br/jspui/handle/123456789/4463 Proposta de melhoria da jornada empreendedora de uma incubadora de base tecnológica: um estudo de caso universitário Entrepreneurship plays a strategic role in regional socioeconomic development, particularly in contexts marked by the need for economic diversification. In this scenario, university-based technology business incubators are relevant mechanisms for fostering innovation and supporting the creation of new ventures. In this context, the present study aims to propose the improvement of the entrepreneurial journey of a university-based technology incubator, based on the evaluation of its first operational cycle and on the theoretical foundation of startup development models throughout the entrepreneurial process. To achieve this objective, a basic research approach was adopted, with a descriptive nature and a qualitative methodology, conducted through a single case study. Data collection was carried out through bibliographic research, document analysis, non-participant observation, and semi-structured interviews with the incubator team and the incubated ventures. The data were analyzed using content analysis techniques, allowing for an understanding of the perceptions, experiences, and practices associated with the incubation process. The results showed that the initial entrepreneurial journey, composed of three stages, contributed to the maturation of ideas, market understanding, and the initial structuring of the ventures, with mentoring, advisory support, and networking standing out as the main valuegenerating factors. However, relevant operational limitations were identified, such as the use of a generic entrepreneurial journey model that did not address the specificities of technology-based businesses, as well as the absence of systematized tools for monitoring and tracking the incubated ventures. Based on the analysis of the collected data and the literature on startup development models, a new entrepreneurial journey structured into five stages, focused on technology-based businesses, was proposed. Additionally, a prototype of a digital system was developed to monitor the progress of startups. The evaluation of the perception of the revised journey and the prototype screens was carried out by specialists, confirming its importance for the incubation process and for the management of the incubator. Dissertação 2026-05-28T00:00:00Z https://repositorio.unifei.edu.br/jspui/handle/123456789/4462 A systematic analysis of security and performance in the internet of drones: re-evaluation and enhancement of the PMAP protocol This dissertation investigates authentication protocols applied to the context of the Internet of Drones (IoD), an environment characterized by high mobility, computational constraints, and strict security requirements. The work is divided into two complementary parts. In the rst part, a systematic literature review is conducted, following established methodological guidelines, with the objective of identifying, classifying, and analyzing recent authentication and key agreement protocols for IoD. Aspects such as communication topologies, threat models, employed cryptographic primitives, security properties analyzed both formally and informally, and performance metrics are examined. In the second part, a technical reassessment of the PMAP protocol is carried out, encompassing the Drone-to-ZSP (D2Z) and Drone-to-Drone (D2D) scenarios. The protocol is analyzed from di erent perspectives, including the formal Real-or-Random (RoR) model, automated veri cation using tools such as AVISPA, Scyther, and ProVerif, an informal analysis of resistance to attacks, and an evaluation of communication and computational costs. The results indicate that, under the adopted models, no violations of the speci ed security properties were identi ed in the formal veri cation procedures. However, the analysis also reveals limitations related to the absence of Perfect Forward Secrecy, exposure to privileged insider attacks, the lack of speci c mitigation mechanisms against denial-of-service attacks, and the computational cost of Hénon map based operations on constrained platforms. From a performance perspective, the protocol proved to be executable in an embedded environment, but with signi cant latency, especially in the D2D scenario. Based on the obtained results, it is observed that the advancement of the eld depends not only on the proposal of new cryptographic mechanisms, but also on the adoption of more standardized and robust evaluation methodologies, combining formal models, informal analyses, and compatible metrics that enable comparison across di erent studies. In this way, this dissertation contributes to a more structured understanding of the properties, limitations, and evaluation challenges of authentication protocols applied to the Internet of Drones. Dissertação 2026-06-02T00:00:00Z https://repositorio.unifei.edu.br/jspui/handle/123456789/4461 Análise da convexidade de funções de superfície de resposta em processos de fabricação Response Surface Methodology (RSM) has proven to be highly relevant in the optimization of industrial processes, as it provides a comprehensive understanding of the relationship between input and output variables while minimizing the number of experiments required for analysis. However, the complexity associated with obtaining saddle-type functions represents a critical challenge, demanding effective approaches to overcome limitations in the search for global optima in multivariate experiments. The convexity of objective functions generated by RSM designs can be analyzed through spectral decomposition. This work presents an analysis of the convexity of functions derived from RSM in different manufacturing processes, applying the aforementioned theory. The study involves the calculation and classification of eigenvalues to identify concave, convex, and saddle-type functions, as well as curvature tests to verify the presence of significant quadratic components. The main consequence of using saddle-type objective functions is that, for this type of optimization, the optima—usually constrained—tend to fall in regions far from the experimental design center, where the prediction variance is extremely high, compromising the quality of optimization models. In this work, an extended set of 240 objective functions obtained from RSM with Central Composite Design (CCD) arrangements was analyzed. The investigation revealed that 71.25% of the analyzed functions exhibited a “saddle-type” behavior, while 14.17% were “concave” and 14.58% “convex.” It was found that 80.42% of the models showed statistically significant curvature and that, in approximately 80% of the cases, the experiments were conducted with fewer center points than recommended, which contributed to increased variance and predictive instability. Among the saddle-type functions, 92.40% required active experimental-space constraints, reinforcing the importance of controlling the hypersphere radius (ρ) to ensure more stable predictions. The results demonstrate that an appropriate balance between the expected response value and variance, combined with the use of additional center points and suitable constraints, constitutes an effective strategy to ensure statistical stability and reliability in the application of RSM to manufacturing processes. Dissertação 2025-10-02T00:00:00Z