Test Maintenance for Machine Learning Systems: A Case Study in the Automotive Industry

Machine Learning (ML) systems have seen widespread use for automated decision making. Testing is essential to ensure the quality of these systems, especially safety-critical autonomous systems in the automotive domain. ML systems introduce new challenges with the potential to affect test maintenance, the process of updating test cases to match the evolving system. We conducted an exploratory case study in the automotive domain to identify factors that affect test maintenance for ML systems, as well as to make recommendations to improve the maintenance process. Based on interview and artifact analysis, we identified 14 factors affecting maintenance, including five especially relevant for ML systems—with the most important relating to non-determinism and large input spaces. We also proposed ten recommendations for improving test maintenance, including four targeting ML systems—in particular, emphasizing the use of test oracles tolerant to acceptable non-determinism. The study’s findings expand our knowledge of test maintenance for an emerging class of systems, benefiting the practitioners testing these systems

Desenvolvimento de metodologia para criação de metaverso imersivo com foco em treinamentos industriais

Orientador: Prof. Dr. Márcio Fontana CatapanCoorientador: Prof. Dr. Pablo Deivid ValleDissertação (mestrado) - Universidade Federal do Paraná, Setor de Tecnologia, Programa de Pós-Graduação em Engenharia de Manufatura. Defesa : Curitiba, 08/12/2022Inclui referências: p. 75-82Resumo: Nos últimos anos, o metaverso tem atraído enorme atenção de todo o mundo com o desenvolvimento de tecnologias relacionadas, como a realidade virtual (RV). Aplicações de metaverso em realidade virtual imersiva, proporcionam experiências partilhadas onde os usuários podem comunicar e interagir no mesmo espaço virtual. Entretanto, o crescimento do metaverso ainda está começando, com grande potencial de melhoria. Quanto a isso, a indústria já chegou avançar a discussão, acompanhada de investimento febril, mas há poucas discussões sobre este assunto no meio acadêmico para orientar cientificamente seu desenvolvimento, principalmente quando se trata na aplicação de treinamentos na indústria. Desta maneira, esta pesquisa propõe uma metodologia de desenvolvimento de metaverso em realidade virtual imersiva com foco em treinamentos industriais. Através da metodologia desenvolvida, foi elaborado um metaverso multiplataforma com o intuito de simular um treinamento industrial, validando a metodologia proposta. Foi criado um questionário para validar com outros desenvolvedores se a metodologia que foi desenvolvida nesta pesquisa está compreensível. A metodologia foi enviada junto com o questionário desenvolvido para 7 voluntários que trabalham utilizando motores de jogos. Como resultado, foi possível analisar que até os desenvolvedores com baixa experiência compreenderam o que foi passado na metodologia, demonstrando que com apenas 6 meses de contato com a ferramenta Unreal Engine já é possível desenvolver metaversos imersivos com foco em treinamentos industriais.Abstract: In recent years, the metaverse has attracted enormous attention from around the world with the development of related technologies such as virtual reality (VR). Metaverse applications in immersive virtual reality, provide shared experiences where users can communicate and interact in the same virtual space. However, the growth of the metaverse is just beginning, with enormous potential for improvement. As for this, the industry has already advanced the discussion, accompanied by feverish investment, but there are few discussions on this subject in academia to scientifically guide its development, especially when it comes to the application of training in the industry. Thus, this research proposes a methodology for developing a metaverse in immersive virtual reality with a focus on industrial training. Through the methodology developed, a multiplatform metaverse was elaborated with the purpose of simulating an industrial training, validating the proposed methodology. A questionnaire was created to validate with other developers if the methodology that was developed in this research is understandable. The methodology was sent along with the developed questionnaire to seven volunteers who work using game engines. As a result, it was possible to analyze that even developers with little experience understood what was passed in the methodology, demonstrating that with only 6 months of contact with the Unreal Engine tool it is already possible to develop immersive metaverses focused on industrial training

Parâmetros térmicos, estrutura e propriedades mecânicas resultantes da solidificação horizontal das ligas de Alumínio com adição de 3 e 5% de Níquel / Thermal parameters, structure and mechanical properties resulting from the horizontal solidification of aluminum alloys with the addition of 3 and 5% Nickel

O objetivo do estudo experimental é avaliar os parâmetros de solidificação, a estrutura e as propriedades mecânicas no processo de solidificação horizontal de ligas binárias de composição Al-3%Ni e Al-5%Ni e efetuar a correlação entre os mesmos. Foram realizados ensaios de microdureza e tração, além de análise micro e macroestrutural. Os parâmetros de solidificação foram obtidos através de aquisição de dados de temperatura. Os resultados encontrados mostraram uma zona intermediária entre a zona colunar e equiaxial denominada de zona de grãos plumosos. Os ensaios mecânicos mostraram que os maiores valores de microdureza e de LRT localizam-se nas regiões com maiores espaçamentos dendríticos

Brane Structure from a Scalar Field in Warped Spacetime

We deal with scalar field coupled to gravity in five dimensions in warped geometry. We investigate models described by potentials that drive the system to support thick brane solutions that engender internal structure. We find analytical expressions for the brane solutions, and we show that they are all linearly stable.Comment: 10 pages, 7 eps figures; version to be published in JCA

Studying the Elimination Pattern of Caprine Arthritis Encephalitis Virus in the Milk of Infected Females

Background: Small ruminants can be infected by lentiviruses, such as Maedi-Visna Virus (MVV) and Caprine ArthritisEncephalitis Virus (CAEV). The main route of transmission is via ingestion of contaminated colostrum and milk although vertical transmission can occur. Recently, several studies for molecular detection of CAEV in milk, using conventional PCR and real-time PCR are being carried out. Considering the elimination of CAEV through the milk of infected animals and the importance of this virus in the goat production, the aim of this study was to evaluate the elimination pattern of  CAEV in milk, evaluating the frequency and the concentration eliminated during the lactation.Materials, Methods & Results: A cohort of four negative females for CAEV was inseminated with semen experimentally infected with CAEV-Cork strain. They were located in stalls at the Hospital of Ruminants from School of Veterinary Medicine and Animal Science from University of São Paulo, Brazil. Goats received coast-cross hay, pellet feeding, mineral salt and water ad libitum. All females were observed every day during pregnancy. After lambing, kids received warm bovine colostrum and bovine milk powder during two months. Forty milk samples were collected at five-day interval during two months. A mixture of five milliliters from each teat was obtained and cDNA extraction was performed using DNA Mini Kit. Initially, real-time PCR was performed using an endogenous control for research of the constitutive gene (12S) for goats. Using positive samples in the first reaction, another reaction was performed using specific primers for lentiviruses based on the gag gene (conserved in retroviruses). In order to compare the results, nested-PCR was performed. After realtime PCR, cDNA was detected in samples from one female, corresponding to the day of calving, 14th, 20th, 25th, 35th and 40th day postpartum (15%; 6/40). The absence of amplified cDNA in thirty days postpartum, as well as in the final twenty days of lactation, was observed. Sample corresponding to the 7th day postpartum was not obtained.  The virus concentration throughout lactation grew up until forty days postpartum. After this period, there was no cDNA amplification. In Nested PCR, positive results were detected in samples corresponding to the day of calving, 15th days, 20th days and 30th days postpartum, only.Discussion: cDNA was detected in samples from one positive female, during forty days postpartum, but not on the 30th. On the other hand, amplified cDNA was observed on 30th day by nested-PCR. In this case, a false negative result was observed after real-time PCR, probably because sample corresponding to 30th days may not have been properly homogenized, so that the fraction used in real-time PCR was not representative. A higher number of positive samples were expected due to the higher sensitivity of the technique used. The low viral concentration in the milk due to high antibody titers, for example, leaded to a small number of cells containing the agent, reducing the possibility of detection. cDNA was not detected in any sample from three infected females. A possible false-positive serological reaction or the very low viral concentration in milk samples could explain the negative results, although some animals might be infected by a strain that could not be recognized by PCR

Aborto equino associado a placentite por Pasteurella pneumotropica

Pasteurella pneumotropica is a bacterium that has so far not been described as a cause of placentitis in animals. Two cases of aborted equine fetuses were sent to the Department of Veterinary Pathology of the “Universidade Federal do Rio Grande do Sul” (SPV-UFRGS) for anatomopathological examination. Both cases presented suppurative placentitis associated with multiple basophilic bacterial cells. After bacterial isolation and biochemical analysis, P. pneumotropica was identified.Pasteurella pneumotropica é uma bactéria que até o momento não foi descrita como causa de placentite em animais. Dois casos de fetos equinos abortados foram enviados ao Setor de Patologia Veterinária da Universidade Federal do Rio Grande do Sul (SPV-UFRGS) para exame anatomopatológico. Em ambos os casos se observou placentite supurativa associada a múltiplas colônias bacterianas basofílicas. Após o isolamento bacteriano e análise bioquímica, indentificou-se P. pneumotropica

Causas de aborto, natimortalidade e morte perinatal em equinos

Causes of abortion, stillbirth, and perinatal mortality in horses were investigated in the Department of Veterinary Pathology of the Federal University of Rio Grande do Sul (SPV-UFRGS) from 2000 to 2015. In this period, 107 cases were analyzed using macroscopic, microscopic, and complementary tests. Of these, 77 were aborted fetuses, 16 were stillbirths, and 14 were perinatal deaths. Conclusive diagnosis was established in 42.8% of the fetuses analyzed, with 28.6% classified as infectious origin, 9.1% as non-infectious, and 5.1% as other. Bacterial infections, especially those related to Streptococcus spp. were the most frequently observed. In stillborn foals, diagnosis was established in 62.5% of cases, and 50% of these were related to non-infectious causes, such as dystocia and birth traumas. As for perinatal mortality, a conclusive diagnosis was reached in 78.57% of cases, and infectious causes associated with bacterial infections accounted for 64.1% of these diagnoses.Causas de aborto, natimortalidade e mortalidade perinatal em equinos foram investigadas no Setor de Patologia Veterinária da Universidade Federal do Rio Grande do Sul (SPV-UFRGS) durante o período de 2000 a 2015. Nesse período, foram analisados 107 casos através de exames macroscópico, microscópico e exames complementares, desses 77 correspondiam a fetos abortados, 16 natimortos e 14 mortes perinatais. Diagnóstico conclusivo foi estabelecido em 42,8% dos fetos analisados e classificados como origem infecciosa em 28,6% dos casos, não infecciosa com 9,1% e outros com 5,1% dos casos. As infecções bacterianas, em especial as relacionadas a Streptococcus spp. foram as mais frequentemente observadas. Em potros natimortos, diagnostico foi estabelecido em 62,5% dos casos, e destes, 50% foram relacionados a causas não infecciosas, como distocia e traumas durante o parto. Quanto a mortalidade perinatal, em 78,57% dos casos houve um diagnostico conclusivo, e as causas infecciosas associadas a infecções bacterianas corresponderam a 64,1% desses diagnósticos

GERENCIAMENTO INTEGRADO DA MANUFATURA EMPREGANDO ARQUITETURA ORIENTADA A SERVIÇOS - GIMSOA

Este artigo descreve o uso do paradigma da Arquitetura Orientada a Serviços (AOS) no gerenciamento de redes industriais, pelo uso de Serviços Web para supervisão e controle de processos industriais. Nesta abordagem foi implementado um emulador de máquina de envasamento de garrafas, utilizando um conjunto de Serviços Web. Protocolos abertos e padrão da Internet como HTTP, XML e SOAP, integrados a protocolos de comunicação industriais (ie. MODBUS e DeviceNET) foram usados. Um aparato experimental foi feito para validação das funcionalidades. Os resultados obtidos mostram as facilidades de abstração do hardware para a implementação da aplicação. Outra vantagem da abordagem AOS é a facilidade de reconfi guração do sistema em caso de mudanças dos CLPs