Estudo sobre modelos de estruturas tridimensionais para impressão 3D aplicadas no desenvolvimento de piezoeletretos

Every day technology advances in a way never seen before. With it, the need arises to capture the analog signals coming from the physical environment around us. Today, we measure almost everything imaginable through sensors. Sensors are devices that interpret signals from the world as input and emit a signal as output. There are several types of sensors that can be applied in di erent contexts, but most of them share costly materials and manufacturing processes. The physical structure of the sensor plays a very important role in the way it responds to environmental stimuli. In this work, a study was made on the types of materials that are most suitable for sensor manufacturing technology through 3D printing. The results were obtained with polymeric materials using the piezoelectricity concept. A piezoelectric sensor is a device that measures pressure or stress measurements by deformation of the material producing an electrical signal in response. This type of sensor has several applications. It is widely used in the construction of microphones, sonars, touch screens, biomedicine and scienti c research for new applications. With this, it was possible to develop printed lms using an innovative manufacturing methodology through 3D printing. The lms produced through this technique were tested and it was observed that the material maintained electrical charges stored for a short period of time proving that the material and methodology used is feasible for the production of piezoelectric sensors.A cada dia a tecnologia avança de uma forma nunca vista antes. Com ela, surge a necessidade de capturar os sinais analógicos advindos do ambiente físico ao nosso redor. Atualmente, medimos quase tudo o que é imaginável através de sensores. Os sensores são dispositivos que interpretam sinais do mundo como entrada e emitem um sinal como saída. Existem diversos tipos de sensores que podem ser aplicados em diferentes contextos, mas, em sua maioria, compartilham de materiais e processos de fabrica c~ao custosos. A estrutura física do sensor tem papel importantíssimo na forma como ele reage aos estímulos do ambiente. Neste trabalho, foi feito um estudo sobre os tipos de materiais que mais se adequam a tecnologia de fabricação de sensores por meio da impressão 3D. Os resultados obtidos foram realizados com materiais poliméricos utilizando-se do conceito da piezoeletricidade. Um sensor piezoelétrico é um dispositivo que afere medidas da pressão ou tensão por meio da deformação do material produzindo um sinal elétrico como resposta.Esse tipo de sensor possui diversas aplicações. Ele é muito usado na construção de microfones, sonares, telas sensíveis ao toque, biomedicina e em varias pesquisas cientificas para novas aplicações. Com isso, foi possível desenvolver filmes impressos utilizando uma metodologia de fabricação inovadora através da impressão 3D. Os fi lmes produzidos através dessa técnica foram testados e observou-se que o material manteve cargas elétricas armazenadas por um curto período de tempo provando que o material e a metodologia usada é viável para produção de sensores piezoelétricos

Finding Software Vulnerabilities in Open-Source C Projects via Bounded Model Checking

Computer-based systems have solved several domain problems, including industrial, military, education, and wearable. Nevertheless, such arrangements need high-quality software to guarantee security and safety as both are mandatory for modern software products. We advocate that bounded model-checking techniques can efficiently detect vulnerabilities in general software systems. However, such an approach struggles to scale up and verify extensive code bases. Consequently, we have developed and evaluated a methodology to verify large software systems using a state-of-the-art bounded model checker. In particular, we pre-process input source-code files and guide the respective model checker to explore them systematically. Moreover, the proposed scheme includes a function-wise prioritization strategy, which readily provides results for code entities according to a scale of importance. Experimental results using a real implementation of the proposed methodology show that it can efficiently verify large software systems. Besides, it presented low peak memory allocation when executed. We have evaluated our approach by verifying twelve popular open-source C projects, where we have found real software vulnerabilities that their developers confirmed.Comment: 27 pages, submitted to STTT journa