The effectiveness of using virtual labs to train students in computer networking skills, when real equipment is limited or unavailable, is uncertain. The purpose of this study was to determine the effectiveness of using virtual labs to train students in the acquisition of computer network configuration and troubleshooting skills. The study was conducted in the developing country of Zambia, where there is an acute shortage of network lab equipment. Effectiveness was determined by the transfer of skills learned in a virtual lab to a real lab. A two stage true experimental design, that compared the proficiency of randomly assigned experimental (virtual-lab) and control (no-virtual-lab) groups, was used to determine effectiveness (N = 56). In the first stage, the virtual-lab group practiced in a virtual lab while the no-virtual-lab group did not. Both groups were subjected to a lab test where the speed and accuracy of network configuration and troubleshooting of real equipment was measured, prior and after treatment. In the second stage, both groups practiced using real equipment and the speed and accuracy was again measured. An independent t-test was used to determine if there was a significant difference in the final performance between the two groups. It was found that there were significant differences between the groups in the configuration time (p = 0.011) and troubleshooting time (p = 0.03), favoring the virtual-lab group. On the other hand, there were no significant difference in configuration accuracy (p = 0.06) and troubleshooting accuracy (p = 0.440) between the two groups. In addition, there was positive transfer of training from the virtual lab to the real lab for configuration accuracy, configuration speed, troubleshooting accuracy and troubleshooting speed. There was also evidence that students showed performance gains both in using virtual and real labs by comparing their pre-test and post-test results. From the results, there is evidence that the use of virtual labs contributes positively to the transfer of practical computer networking skills from the virtual to the real lab environment. Hence, virtual labs were found to be effective in the teaching of computer networking skills relating to configuration and troubleshooting. / Ph. D.

This licentiate thesis considers computer-assisted troubleshooting of complex products such as heavy trucks. The troubleshooting task is to find and repair all faulty components in a malfunctioning system. This is done by performing actions to gather more information regarding which faults there can be or to repair components that are suspected to be faulty. The expected cost of the performed actions should be as low as possible. The work described in this thesis contributes to solving the troubleshooting task in such a way that a good trade-off between computation time and solution quality can be made. A framework for troubleshooting is developed where the system is diagnosed using non-stationary dynamic Bayesian networks and the decisions of which actions to perform are made using a new planning algorithm for Stochastic Shortest Path Problems called Iterative Bounding LAO*. It is shown how the troubleshooting problem can be converted into a Stochastic Shortest Path problem so that it can be efficiently solved using general algorithms such as Iterative Bounding LAO*.  New and improved search heuristics for solving the troubleshooting problem by searching are also presented in this thesis. The methods presented in this thesis are evaluated in a case study of an auxiliary hydraulic braking system of a modern truck. The evaluation shows that the new algorithm Iterative Bounding LAO* creates troubleshooting plans with a lower expected cost faster than existing state-of-the-art algorithms in the literature. The case study shows that the troubleshooting framework can be applied to systems from the heavy vehicles domain.

Since the coronavirus pandemic in 2019, millions of people started to use online streaming and entertainment services during the lockdown. Streaming solutions such as OTT and IPTV has grown and boosted the live streaming and non-linear streaming revenue, by using new technologies and innovation such as Artificial Intelligence (AI) to improve the video quality, performance, and security of video streaming services. However, QoS and QoE guarantee and traffic management is still a challenge to many multimedia services and systems provided over the Internet. In this paper the analysis of a proposed user-friendly design will be discussed, describing how it can improve the management and troubleshooting experience. And in what way an AI knowledge-based agent can be used to improve and support the operators daily tasks and challenges. With an usability test, the results showed that the combination of an user-centered interface and AI-technology can improve the productivity in video troubleshooting and prevention of common issues. The user-centered design focuses on the user’s goal and needs, using interactive products to help the user achieve their goal. And the AI would assist the operators to identifying network congestion, stream quality, and much more.

5G is becoming reality with companies rolling out the technology around the world. In 5G,the Radio Access Network (RAN) is moving from a monolithic-based architecture into a cloud-based microservice architecture for the purpose of simplifying deployment and manageability,and explore scalability and flexibility. Thus, the transition of functionalities from a proprietaryhardware-based system into a more distributed and flexible virtualized system is ongoing. Insuch systems, legacy methods performance monitoring is relevant, wheresystem tracingplaysan important role. System tracing is important for the purpose of performance analysis of anygiven system. However, current tools were designed thinking about monolith architectureswhere, therefore, in new distributed architectures, new tracing tools need to be developed. System tracing often requires special permissions to be executed in applications running ina virtualized third-party environment. Unfortunately, not all applications running in a dis-tributed virtualized environment can be given such special access, at the risk of compromis-ing security and stability of the system. However, tracing data needs to be also collected fromapplications running in such environments. This thesis addresses the challenge of remotely configuring and controlling the system tracingtool with the example of LTTng in applications that run as part of a distributed virtualizedenvironment with Kubernetes. We explore the problem of remotely controlling and configuringsystem tracing as well as to optimize data collection. The main outcome is a tool able to re-motely control and configure system tracing tools. In addition, a proof-of-concept is presentedwith working demos for basic system tracing commands. It was discovered that a relay-based solution can be exposed outside the cluster via node-portwhich can relay incoming requests on-wards to any number of microservices. However, dis-covery of these microservices that are running system tracing tools is critial. Service discoverymechanism’s were brought forth and introduced to the system for the purpose of disoveringmicroservices with system tracing tools. Tracing data that is saved locally can be extracted bythe user through the relay-based solution or sent directly to any remote system using LTTngrelay daemon functionality. Comparison between directly executing commands in a bash shelland the remote CLI was measured. It has been concluded that the overall the response timeof both Linux and LTTng commands that are sent through the remote CLI is 1.96 times longerthan directly executing these commands in a bash shell. This was accounted to the fact thatcommands sent over the network traffic within the kubernetes cluster which is the cost ofremotely being able to control and configure system tracing tools. This being said, there arestill many steps that can be taken to improve the solution and to develop a more productionready solution.i

A perfilagem de colunas por raios gama (column gamma scan) é uma técnica nuclear empregada para solucionar problemas em equipamentos de processos industriais, nas refinarias e petroquímicas. Consiste na utilização de uma fonte selada e um detector de radiação [NaI(Tl)], obtendo-se o perfil de densidade unidimensional (1D) do equipamento. Nas últimas décadas, ocorreram algumas melhorias na técnica de perfilagem, tais como, na digitalização contínua das informações e nos sistemas de detecção da radiação (wireless). Novos aplicativos melhoraram a qualidade da apresentação dos resultados. Entretanto, a condição da técnica não mudou drasticamente, desde sua criação. Seu resultado é simplesmente um gráfico 1D da densidade média, em função da altura do equipamento industrial. A tecnologia inovadora proposta neste trabalho de Mestrado utiliza a reconstrução tomográfica industrial, via algoritmos iterativos derivados da ART (Algebraic Reconstruction Technique) e do MART (Multiplicative Algebraic Reconstruction Technique), para apresentar o resultado de perfilagem como uma imagem bidimensional (2D) da distribuição de densidade, ao invés de um gráfico 1D. Nitidamente, uma imagem 2D possui mais informações técnicas do equipamento em análise, permitindo um avanço na tecnologia de ensaios não destrutivos (END). Assim, muitos problemas operacionais não detectáveis em equipamentos de processos industriais podem ser descobertos e solucionados de forma on-line, usando-se o imageamento 2D. Esta tecnologia permitiu que um pedido de patente fosse depositado junto ao Instituto Nacional de Propriedade Industrial (INPI). / Column gamma scan is one of the most common nuclear techniques on troubleshooting industrial process equipments like distillation columns and reactors. With a very simple concept, the technique is easy to implement. Searching for a competitive edge the industry has been long developing solutions to achieve better results. On the last decades, significant development has been done with the advent of new hardware, electronics, portable computers and software. Continuous scanning and wireless detection systems are examples of successful field solutions, while new software aid on reporting and data presentation. However the type and quality of the results itself has not dramatically changed since its beginning. A scan profile is simple to understand, although the process to build it can be very complex as it requires a specific blend of knowledge and abilities. Process engineering, chemical engineering, internal hydraulic project, nuclear engineering and field abilities are pre requisites for of any scan specialist. Correct data gathering, interpretation and reporting are abilities often difficult to match or requires a long time of training. The industry faces a similar difficult on the customer side, as it is always necessary to train end users to understand a report and how to use its best. This scientific work describes our effort on developing a new approach on the gamma column scan test using image reconstruction techniques that would result on a graphic image rather than a XY plot. Direct and easier to understand, a report with graphic images would be also be accessible to a wider audience, not limited to the customers experienced with gamma scan interpretation.

A perfilagem de colunas por raios gama (column gamma scan) é uma técnica nuclear empregada para solucionar problemas em equipamentos de processos industriais, nas refinarias e petroquímicas. Consiste na utilização de uma fonte selada e um detector de radiação [NaI(Tl)], obtendo-se o perfil de densidade unidimensional (1D) do equipamento. Nas últimas décadas, ocorreram algumas melhorias na técnica de perfilagem, tais como, na digitalização contínua das informações e nos sistemas de detecção da radiação (wireless). Novos aplicativos melhoraram a qualidade da apresentação dos resultados. Entretanto, a condição da técnica não mudou drasticamente, desde sua criação. Seu resultado é simplesmente um gráfico 1D da densidade média, em função da altura do equipamento industrial. A tecnologia inovadora proposta neste trabalho de Mestrado utiliza a reconstrução tomográfica industrial, via algoritmos iterativos derivados da ART (Algebraic Reconstruction Technique) e do MART (Multiplicative Algebraic Reconstruction Technique), para apresentar o resultado de perfilagem como uma imagem bidimensional (2D) da distribuição de densidade, ao invés de um gráfico 1D. Nitidamente, uma imagem 2D possui mais informações técnicas do equipamento em análise, permitindo um avanço na tecnologia de ensaios não destrutivos (END). Assim, muitos problemas operacionais não detectáveis em equipamentos de processos industriais podem ser descobertos e solucionados de forma on-line, usando-se o imageamento 2D. Esta tecnologia permitiu que um pedido de patente fosse depositado junto ao Instituto Nacional de Propriedade Industrial (INPI). / Column gamma scan is one of the most common nuclear techniques on troubleshooting industrial process equipments like distillation columns and reactors. With a very simple concept, the technique is easy to implement. Searching for a competitive edge the industry has been long developing solutions to achieve better results. On the last decades, significant development has been done with the advent of new hardware, electronics, portable computers and software. Continuous scanning and wireless detection systems are examples of successful field solutions, while new software aid on reporting and data presentation. However the type and quality of the results itself has not dramatically changed since its beginning. A scan profile is simple to understand, although the process to build it can be very complex as it requires a specific blend of knowledge and abilities. Process engineering, chemical engineering, internal hydraulic project, nuclear engineering and field abilities are pre requisites for of any scan specialist. Correct data gathering, interpretation and reporting are abilities often difficult to match or requires a long time of training. The industry faces a similar difficult on the customer side, as it is always necessary to train end users to understand a report and how to use its best. This scientific work describes our effort on developing a new approach on the gamma column scan test using image reconstruction techniques that would result on a graphic image rather than a XY plot. Direct and easier to understand, a report with graphic images would be also be accessible to a wider audience, not limited to the customers experienced with gamma scan interpretation.

O objetivo deste trabalho de pesquisa foi de fazer a modelagem por meio de sistemas de inferência Fuzzy da análise da concentração dos gases dissolvidos no óleo mineral isolante e desta forma diagnosticar defeitos elétricos internos em transformadores de Potência. Assim sendo o sistema proposto deve fornecer respostas que auxiliem no diagnóstico de falhas e avarias nos interiores dos transformadores e no processo de tomada de decisões no acompanhamento da evolução destas falhas de forma a aumentar a confiabilidade em relação à utilização dos métodos individualmente. O sistema desenvolvido baseou-se na pesquisa acadêmica de normas e técnicas mais utilizadas na literatura que relacionam o gás dissolvido no óleo mineral isolante com a falha. O sistema proposto foi validado por meio de dados reais de dois transformadores pilotos e vários sistemas Fuzzy foram construídos, cada um especialista em um determinado método. Os resultados encontrados mostraram-se compatíveis com aqueles obtidos pelos métodos convencionais comprovando que a ferramenta pode ser utilizada como suporte para uma análise rápida e confiável do estado do óleo isolante dos transformadores. / The objective of this research was to model by analyzing the fuzzy inference systems the concentration of gases dissolved in the insulating oil and diagnosing thereby internal defects in electrical power transformers. Therefore the proposed system should provide answers that help in the diagnosis of faults and malfunctions in the interiors of the transformers and in the decision-making process in monitoring the evolution of these failures in order to increase the reliability regarding the use of the methods individually. The system developed was based on academic research standards and techniques commonly used in the literature relating the gas dissolved in the insulating oil with failure. The proposed system was validated by real data of two pilots transformers and various Fuzzy systems were built, each an expert in a particular method. The results were compatible with those obtained by conventional methods proving that the tool can be used as support for quick and reliable analysis of the insulating oil condition of transformers.

Orientadora: Profa. Dra. Virgínia Cardia Cardoso / Dissertação (mestrado) - Universidade Federal do ABC, Programa De Pós-Graduação em Ensino, História, Filosofia das Ciências e Matemática, 2015. / O presente trabalho consiste na análise de um projeto para o ensino de frações. O referencial teórico adotado foi a Teoria das Inteligências Múltiplas de Howard Gardner, que assume a ideia de que a inteligência humana seria multifacetada, totalizando um espectro formado por oito inteligências: corporal-cinestésica, espacial, interpessoal, intrapessoal, lógico-matemática, linguística, musical e naturalista. Serão relatados os principais pontos da teoria de Gardner, dentre eles, a importância de uma educação que considere as individualidades cognitivas dos educandos, a concepção de inteligência baseada na capacidade de resolver problemas e a abordagem dos conteúdos escolares por meio de cinco pontos de entrada: narrativo, fundamental, por uma abordagem estética, lógico-quantitativo e experimental. Com base nos pressupostos educacionais da teoria e no levantamento das problemáticas relacionadas ao ensino de frações, apresentaremos o projeto de ensino elaborado pela autora deste trabalho e o seu desenvolvimento em uma escola da rede pública municipal de São Paulo, em uma pesquisa-ação com a observação participante de uma turma do quinto ano do ensino fundamental que buscou verificar que contribuições emergiriam das práticas adotadas para a compreensão de tópicos relacionados aos números racionais em sua forma fracionária. Os resultados mostraram que a abordagem utilizada possibilitou avanços na aprendizagem dos alunos nos conteúdos matemáticos trabalhados, em um contexto educacional que teve em suas finalidades propiciar o estímulo e o desenvolvimento de suas inteligências. / This work is the analysis of a project for teaching fractions. The theoretical framework adopted was the Theory of Multiple Intelligences of Howard Gardner, who takes the view that human intelligence would be multifaceted, totaling a spectrum made up of eight intelligences: bodily-kinesthetic, spatial, interpersonal, intrapersonal, logical-mathematical, linguistic, Music and naturalist. The main points will be reported in Gardner's theory, including the importance of an education that consider the cognitive legend of the students, the concept of intelligence-based problem-solving skills and the approach of school subjects through five entry points: narrative, critical, for an aesthetic approach, logical-quantitative and experimental. Based on the assumptions of educational theory and survey of issues related to teaching fractions, we will present the educational project developed by the author of this work and its development in a municipal public school of São Paulo, in an action research with participant observation of a group of fifth grade of elementary school who sought to verify that emerge contributions of practices for understanding topics related to rational numbers in its fractional form. The results showed that the approach has enabled advances in student learning in mathematical contents worked in an educational context he had in his purposes provide the stimulation and the development of their intelligence.

O objetivo deste trabalho de pesquisa foi de fazer a modelagem por meio de sistemas de inferência Fuzzy da análise da concentração dos gases dissolvidos no óleo mineral isolante e desta forma diagnosticar defeitos elétricos internos em transformadores de Potência. Assim sendo o sistema proposto deve fornecer respostas que auxiliem no diagnóstico de falhas e avarias nos interiores dos transformadores e no processo de tomada de decisões no acompanhamento da evolução destas falhas de forma a aumentar a confiabilidade em relação à utilização dos métodos individualmente. O sistema desenvolvido baseou-se na pesquisa acadêmica de normas e técnicas mais utilizadas na literatura que relacionam o gás dissolvido no óleo mineral isolante com a falha. O sistema proposto foi validado por meio de dados reais de dois transformadores pilotos e vários sistemas Fuzzy foram construídos, cada um especialista em um determinado método. Os resultados encontrados mostraram-se compatíveis com aqueles obtidos pelos métodos convencionais comprovando que a ferramenta pode ser utilizada como suporte para uma análise rápida e confiável do estado do óleo isolante dos transformadores. / The objective of this research was to model by analyzing the fuzzy inference systems the concentration of gases dissolved in the insulating oil and diagnosing thereby internal defects in electrical power transformers. Therefore the proposed system should provide answers that help in the diagnosis of faults and malfunctions in the interiors of the transformers and in the decision-making process in monitoring the evolution of these failures in order to increase the reliability regarding the use of the methods individually. The system developed was based on academic research standards and techniques commonly used in the literature relating the gas dissolved in the insulating oil with failure. The proposed system was validated by real data of two pilots transformers and various Fuzzy systems were built, each an expert in a particular method. The results were compatible with those obtained by conventional methods proving that the tool can be used as support for quick and reliable analysis of the insulating oil condition of transformers.

It was not long ago. On Christmas Eve 2012, a war of troubleshooting began in Amazon data centers. It started at 12:24 PM, with an mistaken deletion of the state data of Amazon Elastic Load Balancing Service (ELB for short), which was not realized at that time. The mistake first led to a local issue that a small number of ELB service APIs were affected. In about six minutes, it evolved into a critical one that EC2 customers were significantly affected. One example was that Netflix, which was using hundreds of Amazon ELB services, was experiencing an extensive streaming service outage when many customers could not watch TV shows or movies on Christmas Eve. It took Amazon engineers 5 hours 42 minutes to find the root cause, the mistaken deletion, and another 15 hours and 32 minutes to fully recover the ELB service. The war ended at 8:15 AM the next day and brought the performance troubleshooting in data centers to world’s attention. As shown in this Amazon ELB case.Troubleshooting runtime performance issues is crucial in time-sensitive multi-tier cloud services because of their stringent end-to-end timing requirements, but it is also notoriously difficult and time consuming. To address the troubleshooting challenge, this dissertation proposes VScope, a flexible monitoring and analysis system for online troubleshooting in data centers. VScope provides primitive operations which data center operators can use to troubleshoot various performance issues. Each operation is essentially a series of monitoring and analysis functions executed on an overlay network. We design a novel software architecture for VScope so that the overlay networks can be generated, executed and terminated automatically, on-demand. From the troubleshooting side, we design novel anomaly detection algorithms and implement them in VScope. By running anomaly detection algorithms in VScope, data center operators are notified when performance anomalies happen. We also design a graph-based guidance approach, called VFocus, which tracks the interactions among hardware and software components in data centers. VFocus provides primitive operations by which operators can analyze the interactions to find out which components are relevant to the performance issue. VScope’s capabilities and performance are evaluated on a testbed with over 1000 virtual machines (VMs). Experimental results show that the VScope runtime negligibly perturbs system and application performance, and requires mere seconds to deploy monitoring and analytics functions on over 1000 nodes. This demonstrates VScope’s ability to support fast operation and online queries against a comprehensive set of application to system/platform level metrics, and a variety of representative analytics functions. When supporting algorithms with high computation complexity, VScope serves as a ‘thin layer’ that occupies no more than 5% of their total latency. Further, by using VFocus, VScope can locate problematic VMs that cannot be found via solely application-level monitoring, and in one of the use cases explored in the dissertation, it operates with levels of perturbation of over 400% less than what is seen for brute-force and most sampling-based approaches. We also validate VFocus with real-world data center traces. The experimental results show that VFocus has troubleshooting accuracy of 83% on average.