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Detecção de fraudes em auditoria interna por meio de algoritmos de aprendizado semi-supervisionado
(Universidade Federal de Lavras, 2025-09-29) Pedroso, Sérgio Herique de Carvalho; Lacerda, Wilian Soares Lacerda; Barbosa, Bruno Henrique Groenner; Rodrigues, Thiago de Souza
This study investigated the application of machine learning algorithms to support fraud and anomaly detection in accounting data from a logistics company. The dataset was extracted from the ERP (Enterprise Resource Planning) system, covering road fleet service records acquired between 2023 and 2025. Three semi-supervised learning strategies were compared, Active Learning, Pseudo-Labeling, and Label Propagation, applied to different models, including Logistic Regression, MLP, XGBoost, and CatBoost. The experimental protocol consisted of running each model-strategy combination over 10 independent repetitions, with stratified sampling and a fixed test set used exclusively for final evaluation. Results showed that Active Learning, particularly when combined with CatBoost, achieved the best performance, with an F1 score of 0.94 and PR-AUC of 0.98. As the second-best approach, CatBoost with Label Propagation reached an F1 score of 0.80 and PR-AUC of 0.87. In contrast, Pseudo-Labeling exhibited limitations in later iterations due to noise propagation from pseudo-labels. In practical terms, the findings demonstrate the potential of integrating semi-supervised learning techniques into internal auditing processes, enabling greater efficiency in prioritizing suspicious cases, reducing operational costs, and strengthening corporate governance.
Manual Técnico do Programa Nacional de Alimentação Escolar (PNAE)
(Universidade Federal de Lavras, 2025-12-08) Silveira, Adalise Dayane Vieira da; Vilas Boas, Lucas Guedes; Pereira, Viviane Santos; Franco Júnior, Kleso Silva; Assis, Thiago Rodrigo de Paula; Santos, Higor Mozart Geraldo
The National School Feeding Program (PNAE) is one of Brazil’s oldest and most comprehensive public policies on food and nutritional security, ensuring the right to adequate and healthy food for public school students. Since the enactment of Law No. 11.947/2009, which requires that at least 30% of program funds be used to purchase food products from family farming, the PNAE has played a key role in fostering local and sustainable development. This dissertation aimed to develop a technical manual for the Technical Assistance and Rural Extension Company of Minas Gerais (EMATER-MG), in order to enhance the performance of extension agents and other stakeholders involved in the implementation of the PNAE. The methodology employed was a narrative and documentary literature review, based on legislation, technical publications, and scientific articles related to the program. The research resulted in the development of a technical guide designed to assist family farmers, extension professionals, and public managers in understanding the regulations, operational procedures, and best practices concerning the PNAE. It is concluded that the production of accessible and updated technical materials is crucial to improve program management, expand the participation of family farming, and strengthen food and nutritional security among Brazilian students.
Fornecimento de flushing com silagem de milho moído e reidratado a cabras da raça Saanen
(Universidade Federal de Lavras, 2025-04-29) Dias, Brenda Veridiane; Alves, Nadja Gomes; Leite, Rafael Fernandes; Lima, Renato Ribeiro de; Bispo, Charles André Souza; Figueira, Lucas Machado
The objective was to evaluate the impact of replacing ground corn (GC) with rehydrated ground corn silage (RGCS) in flushing diets on productive performance, feeding behavior, metabolites, follicular development, and ovulations in Saanen goats. Thirty-six non-lactating goats were blocked by body condition score (BCS) and randomly assigned to one of three treatments: maintenance diet (control, n=12), GC flushing (n=12), or RGCS flushing (n=12) for 24 days. The estrus synchronization protocol began on the 12th day. Goats were weighed, and BCS and subcutaneous backfat thickness (SFT; mm) were measured on the day before feeding the diets (d-0; covariate) and on days 7, 14, and 21. Blood samples (days 0, 7, 14, and 21) were analyzed for glucose and urea. Feeding behavior was assessed (days 13-14) using 24-h scans at fiveminute intervals. Digestibility was evaluated via total fecal collection over five days, and apparent digestibility coefficients for dry matter (DM) and nutrients were calculated. Ovaries were assessed daily by ultrasonography from day 20 until ovulation. After 10 days, the corpora lutea was assessed. Analyses were performed in SAS software, with generalized models for intake, digestibility, feeding behavior, and reproductive data. Mixed models were used for metabolite concentrations. Treatment effects were compared using orthogonal contrasts: 1) control diet vs. flushing, and 2) GC vs. RGCS, with significance set at 5%. All nutrients, except NDF and ash, showed higher intake in flushing diets (GC and RGCS) compared to the maintenance diet (CON). Flushing diets with GC and RGCS did not differ (P>0.05) in terms of intake of DM, protein, ether extract, non-fibrous carbohydrates, and starch, indicating that both sources are equivalent. Final body weight was higher in the RGCS group (P<0.05). Plasma glucose concentrations did not differ between treatments (P>0.05). Plasma urea nitrogen (PUN) concentrations were lower (P<0.05) in goats fed flushing diets, suggesting better nitrogen utilization. On day 21, concentrations differed between goats fed GC and RGCS (13.0±1.26 mg and 8.3±1.24 mg dL⁻¹, respectively). Follicular growth was more pronounced in the flushing groups (P<0.05), but the total number of ovulations did not significantly differ between treatments (P>0.05). The number and diameter of follicles did not differ (P>0.05) between treatments, but a higher follicular growth rate (P<0.01) was observed in animals fed flushing diets. The number of ovulations was 1.47 in the control group, 1.18 in animals fed GC, and 1.94 in those fed RGCS (P>0.05). Total luteal area differed between flushing treatments and was greater in animals in the RGCS group (2.76 vs. 1.56; P<0.05). Goats fed flushing diets required less time for feeding, rumination, and total chewing activity. The feeding efficiency of DM and NDF was greater in animals fed RGCS, and a higher number of chews per ruminal bolus was observed in these animals. It was concluded that replacing GC with RGCS in flushing diets does not impair feeding behavior and improves DM and NDF efficiency, resulting in higher weight gain. Flushing diets resulted in a higher follicular growth rate, with a greater total luteal area observed in the RGCS diet.
Biocarvão de borra de café pelo processo hidrotermico com níquel (ii) ou cobre (ii) como precursor de carvão ativado
(Universidade Federal de Lavras, 2025-09-26) Alves, Rafael Pereira; Guerreiro, Mário César; Bianchi, Maria Lucia; Caetano, Aline Aparecida
Brazil, the world's largest coffee producer, generates large volumes of coffee grounds as waste, approximately 450 kg of dry grounds per ton of coffee processed. This work proposes the reuse of this byproduct as a carbonaceous precursor for the production of hydrochars by hydrothermal carbonization (HTC) catalyzed by metal ions (Ni2+ and Cu2+) and, subsequently, of activated carbon by physicochemical activation. The HTC process was conducted in the absence and presence of metal ions (Cu2+ and Ni2+), with the aim of evaluating their catalytic influence. The results demonstrated that HTC promoted the formation of carbonaceous and polyaromatic structures, with higher yields in hydrochars prepared with metal ions (Cu2+ and Ni2+), highlighting the catalytic effect of these ions in the hydrolysis, dehydration, and repolymerization reactions of the biomass. After physicochemical activation, the carbons presented estimated surface areas of 801 m2·g−1 (AC-Cu) and 729 m2·g−1 (AC-Ni), while the reference carbon Alpha-W810, evaluated by the same method, exhibited an area of 502 m2·g−1. In the methylene blue isotherms, the AC-Cu and AC-Ni carbons exhibited maximum adsorption capacities of 415 mg·g−1 and 378 mg·g−1, respectively, values higher than those obtained for the Alpha-W810 carbon (260 mg·g−1) under the same conditions. The isotherms were best fitted by the Langmuir model, confirming adsorption onto homogeneous monolayers, while the kinetics followed the pseudo-second-order model, suggesting a predominance of chemisorption. In summary, metal ion-catalyzed HTC proved to be an efficient strategy and, when combined with physicochemical activation, demonstrated the potential to produce activated carbons with high adsorptive performance, suitable for applications as adsorbents in the treatment of aqueous effluents and environmental remediation.
Compostos orgânicos voláteis em queijos minas artesanal de casca florida natural: estudos aplicados ás microrregiões da canastra e de Diamantina
(Universidade Federal de Lavras, 2025-07-17) Mansur, Bethânia Leite; Saczk, Adelir Aparecida; Magalhães, Elisângela Jaqueline; Botelho, Bruno Gonçalves; Boari, Cleube Andrade; Abreu, Luiz Ronaldo de; Pedroso, Marcio Pozzobon
Minas Gerais artisanal cheeses have achieved national and international awards in competitions. The traditional method of producing Artisanal Minas Cheese has been designated as Intangible Cultural Heritage of Humanity by UNESCO, underscoring its cultural significance. The primary objective of this study was to deepen the understanding of the volatile compound profile in Natural Bloomy Rind Artisanal Minas Cheese (NBRAMC) and Artisanal Minas Cheese produced in the Diamantina microregion. Emphasis was placed on regional identity and the influence of factors such as ripening time, production practices, and seasonal climatic conditions, utilizing HS-SPME coupled with GC-MS, alongside chemometric analyses such as Principal Component Analysis (PCA) and Partial Least Squares Discriminant Analysis (PLS-DA). In the first article, NBRAMC samples were analyzed, and 67 volatile compounds were identified. PCA revealed that the primary differentiation among samples was attributed to the cheese portion analyzed (surface or core), rather than ripening time or producer. The second article focused on the influence of climatic conditions (rainy and dry seasons) on the volatile compound profile of artisanal cheeses from the Diamantina microregion. Although PCA was unable to clearly group samples based on seasonality or cheese portion (surface or core), PLS- DA demonstrated a high classification capability between samples from the rainy and dry seasons. This indicates that, despite not being visually apparent in reduced dimensions, volatile patterns exist that allow for the discrimination of samples by seasonality. Supporting literature reinforces that the microbiota of artisanal cheese, and consequently volatile compound production, is significantly affected by seasonal conditions, including temperature and humidity variations, as well as pasture composition, which directly influences the milk. In conclusion, this thesis demonstrated the complexity and dynamism of the volatile compound profile in artisanal cheeses, revealing that both the producer's "know-how" and seasonal environmental conditions significantly impact the final product's sensory characteristics. The identification of these volatile compounds and the ability to classify them by various factors contribute to the cultural, social, and economic valorization of Brazilian artisanal cheeses, providing important tools for the authenticity and quality control of these products.