Methodology for WSN communication technologies automated field tests

Wireless Sensor Networks(WSN) are networks of devices used to sense and act that applies wireless radios to communicate. To achieve a successful implementation of a wireless device it is necessary to take in consideration the existence of a wide variety of radios available, a large number of communication parameters (payload, duty cycle, etc.) and environmental conditions that may affect the device’s behaviour. However, to evaluate a specific radio towards a unique application it might be necessary to conduct trial experiments, with such a vast amount of devices, communication parameters and environmental conditions to take into consideration the number of trial cases generated can be surprisingly high. Thus, making trial experiments to achieve manual validation of wireless communication technologies becomes unsuitable due to the existence of a high number of trial cases on the field. To overcome this technological issue an automated test methodology was introduced, presenting the possibility to acquire data regarding the device’s behaviour when testing several technologies and parameters that care for a specific analysis. Therefore, this method advances the validation and analysis process of the wireless radios and allows the validation to be done without the need of specific and in depth knowledge about wireless devices

Assessment of improvement techniques effect on fatigue behaviour of friction stir welded aerospace aluminium alloys

AbstractThis research work is based on analysis of the improvement of friction stir welded joints of the aerospace aluminium alloy AA2024-T351. Therefore, initially, the Taguchi method was used to obtain the optimal FSW parameters for improvement its mechanical behaviour. Then the fatigue resistance of base material, joints in as-welded condition and sound and defective FSW welded joints improved by grinding were detailed investigated. The influence of process parameters was addressed via statistical analysis of weld bead appearance parameters, mechanical tensile and bending resistance, metallurgical features and hardness field characterization. Validation tests demonstrate the Taguchi design’s feasibility in the optimization of the FSW parameters and fatigue results show the resistance of improved welded joints overcoming base material

Monitoring of the mechanical load and thermal history during friction stir channelling under constant position and constant force control modes

UID/EMS/50022/2019 UID/EMS/00667/2019In the present investigation, constant position and constant force process control modes; and representative process temperature measurements were analysed during the application of the friction stir channelling process. The experimental tests were carried out using rolled plates of AA5083-H111 with thickness of 15 mm. Results show that the FSC process was found not stable during the forward traverse movement stage when it is performed via position control. For both control modes, the tool was subjected to a more severe loading during the initial plunge than during the channelling period. Moreover, it was found that the tool vertical position is not significantly affected during the channelling stage when the process was force controlled. From the temperature measurements carried out, it was recorded a maximum process temperature of about 330 °C.publishersversionpublishe

The influence of chemical reaction conditions upon poly(styrene‐methyl methacrylate‐acrylic acid) synthesis: Variations in nanoparticle size, colour and deposition methods

Monodisperse latex nanospheres of poly(styrene‐methyl methacrylate‐acrylic acid) with different sizes were synthetised by soap‐free emulsion copolymerisation and applied onto polyamide 6,6 fabrics by two methods, ie, gravitational sedimentation and dip‐drawing. Different‐sized nanospheres were synthetised by varying temperature and stirring velocity as reaction parameters. Scanning electron microscopy and scanning transmission electron microscopy were used to evaluate nanosphere sizes and deposition structures. The results showed two different nanosphere structural arrangements on the fabric surface, a hexagonal packed centre structure in the even surfaces and a square arrangement in the out‐of‐plane surfaces. Different colours were observed according to particle size, namely, violet (ca. 170 nm), blue (ca. 190 nm), green (ca. 210 nm), yellow (ca. 230 nm) and red (ca. 250 nm). An iridescence effect was also observed, displaying different colours at different observation angles. By controlling the size of the nanospheres it was possible to obtain different, brilliant and iridescent colours. Using different nanosphere sizes it was possible to obtain different interplanar distances and to control the light scattering in the crystalline lattice planes, obtaining Bragg diffraction patterns.Fundação para a Ciência e a Tecnologia, Grant/Award Number: IF/00071/2015, PTDC/CTM-TEX/28295/2017 , SFRH/BD/145269/2019 and UID/CTM/00264/2019; European Regional Development funds (FEDER); Competitiveness and Internationalization Operational Program (POCI)—COMPETE, Grant/Award Number: POCI-01-0145-FEDER-0071

Automatic pre-bended customized prosthesis for pectus excavatum minimal invasive surgery correction

Pectus excavatum is the most common deformity of the thorax. A minimally invasive surgical correction is commonly carried out to remodel the anterior chest wall, by employing an intrathoracic convex prosthesis in substernal position. The process of prosthesis modeling and bending still remains an area of improvement. The authors developed a new system, i3DExcavatum, which can automatically model and bend the bar preoperatively based on a thoracic CT-scan. This paper presents a comparison between automatic and manual bending. The i3DExcavatum was used to personalize prosthesis for 41 patients who underwent pectus excavatum surgical correction between 2007 and 2012. Regarding the anatomic variations, the soft tissue thicknesses external to the ribs show that symmetric or asymmetric patients have always asymmetric variations by comparing both patients’ sides. It highlighted that the prosthesis bar should be modeled according to each patient ribs position and dimension. The average differences between the skin and costal line curvature lengths were 84±4 mm and 96±11mm, for male and female patients, respectively. On the other hand, the i3DExcavatum ensured a smooth curvature of the surgical prosthesis and was capable to predict and simulate a virtual shape and size of the bar for asymmetric or symmetric patients. In conclusion, the i3DExcavatum allows preoperative personalization according to the thoracic morphology of each patient. It reduces surgery time and minimizes the margin error induced by the manual bended bar shape that only uses a template that copies the chest wall curvature

Multiyear and multi-criteria AC Transmission Expansion Planning model considering reliability and investment costs

One of the major concerns in Power Systems issurely related with their reliability. Long-term expansionplanning studies traditionally use the well-known deterministic"N-1" contingency criterion. However, this criterion is appliedbased on worst-case analyses and the obtained plan mayoriginate over-investments. Differently, probabilistic reliabilityapproaches can incorporate different type of uncertainties thataffect power systems. In this work, a long term multi-criteriaAC Transmission Expansion Planning model was developedconsidering two objectives - the probabilistic reliability indexExpected Energy Not Supplied (EENS) and the investment cost.The Pareto-Front associated with these two objectives wasobtained using Genetic Algorithms and the final solution wasselected using a fuzzy decision making function. This approachwas applied to the IEEE 24 Bus Test System and the resultsensure its robustness and efficiency

Um sistema de controlo de acessos baseado no modelo cargo-organização

Dissertação de mestrado em Engenharia de InformáticaO paradigma do controlo de acessos, em especial o controlo de acesso à informação, tem vindo a mudar nos últimos anos. Controlo este que inicialmente era efetuado pelas próprias aplicações de forma isolada e autónoma, sem a possibilidade de consultarem ou se integrarem com qualquer sistema centralizado. Todavia, com o crescente uso das tecnologias de informação nas organizações, novas soluções (tais como os serviços de diretoria LDAP) têm vindo a ser adotadas com o intuito de dar resposta à necessidade de uma política de acessos unificada e coesa, transversal aos diversos serviços e aplicações. Estas soluções representam uma mais-valia no desempenho das tarefas organizacionais. Tendo em conta esta necessidade, este trabalho propõe uma nova solução para o controlo de acessos físicos e lógicos através da apresentação e implementação de um novo modelo de controlo de acessos baseado no par Cargo-Organização. É ainda apresentada e implementada neste projeto uma nova abordagem no controlo de acessos lógicos, sendo esta assim capaz de interagir e configurar aplicações que carecem do suporte de protocolos e mecanismos padrão para o controlo de acessos.The access control paradigm has been changing in the past years, specially what regards the access control to information. Information access control was originally achieved independently by each application without querying or interacting with a central system. However, due to the increasing usage of information technologies, new solutions (such as LDAP services) have been put in place in order to obtain a unified access policy across different services and applications. These solutions greatly improve the performance of organizational tasks. This project aims to present a new access control solution for both physical and logical layers. Therefore, a new access control model based on the pair Role/Organization is presented, as well as a concrete implementation of this model. Bearing in mind that not all applications support access control protocols, another approach (which allows the interaction with these applications) is also taken. In this context, after presenting the conceptual organization of the proposed solution, along with some implementation details, some illustrative evaluation tests are also presented and discussed

Gestão da produção em ambiente híbrido de fabrico para stock e por encomenda numa empresa de produção de linhas de costura

Dissertação de mestrado em Engenharia Industrial (área de especialização em Gestão Industrial)Esta dissertação de mestrado relata o trabalho desenvolvido de organização e gestão integrada da produção e de stocks de linhas ou fios de costura na Liconfe, uma empresa de rebobinagem de linhas em cones a partir de bobines de fio cru ou tingido, de Barcelos, Portugal. Devido à variedade de referências de artigo, frequentemente referidas nesta dissertação como cores, a opção da empresa de produção para stock de todas as referências, com vista à garantia de um elevado serviço ao cliente, foi sujeita a um estudo e análise crítica, já que os encargos de stock eram demasiado elevados com tal política e, frequentemente, a qualidade de serviço pretendido não era atingido devido a frequentes ruturas de stock, agravadas por restrições severas de entrega de pedidos de tingimento de fio. O objetivo era reduzir os encargos de stock e se possível melhorar o serviço ao cliente. Assim, o estudo teve como objetivo desenvolver uma abordagem mais racional à produção e armazenagem de linhas, procurando reduzir stocks, pelo menos da grande maioria dos artigos, e ao mesmo tempo melhorar a qualidade do serviço ao cliente. Foi proposta uma metodologia de gestão integrada da produção e de stocks diferenciada por classes de artigo, numa lógica híbrida de produção para stock e por encomenda. No sentido de reduzir a complexidade da análise, e chegar a resultados úteis no tempo disponível, fez-se a opção de tratar apenas o fio poliéster, por ter uma contribuição elevada, cerca de 80%, para as vendas da empresa, reduzindo assim o leque de referências de análise para aproximadamente um milhar. Assim, foram feitas análises ABC às vendas das cores, em diferentes períodos recentes, estendidos por ano e meio de vendas, e decidido que os artigos da classe A, que contavam para cerca de 70% das vendas, deveriam ser produzidos para stock com níveis que reduzissem o risco de rutura então existente, tendo em conta a procura prevista e o tempo de entrega do serviço de tingimento de 15 dias. Os artigos da classe B manteriam a abordagem de gestão usada, que era garantir um nível mínimo de stock e, sempre que houvesse ruturas negociar a eventual entrega no prazo possível, produzindo por encomenda. A principal diferença entre estas classes, é que em geral os produtos da classe B mantêm um nível inferior de stock e os níveis de reposição praticamente não variam nesta classe. Para os artigos da classe C propôs-se a produção por encomenda. Estes constituem a maior variedade, mais de 50% das cores, mas verificou-se terem uma contribuição pequena nas vendas, entre 9% a 10%. Quando forem produzidos, devido à quantidade mínima de tingimento de 35Kg, a quantidade que é rebobinada e não vendida, é mantida em inventário. Esta abordagem híbrida é facilitada pelo facto de haver extrema flexibilidade na mudança de artigo e rebobinagem, com a existência de cerca de 100 fusos de rebobinagem, sendo possível satisfazer várias encomendas em menos de uma hora, a partir de matéria-prima tingida. As propostas apresentadas estão a ser implementadas, não havendo, no entanto, ainda, dados concretos da implementação. No entanto argumenta-se com estudo e análise que a abordagem proposta à gestão integrada da produção e de stocks pode atingir os objetivos estipulados. No trabalho também se propõe e implementa uma reestruturação da área de armazenagem, por forma a reduzir o desperdício de tempo e carga física na manipulação e transporte dos conjuntos de bobines tingidas para rebobinar. Concluiu-se também que a utilização da produção híbrida MTS-MTO, aliada à análise dinamicamente atualizada da classificação ABC dos artigos, é uma estratégia que tende a reduzir ruturas de stock em relação ao volume de vendas e portanto melhorar a qualidade de serviço da empresa, melhorando assim a satisfação do cliente.This master dissertation reports a study of production and inventory integrated management procedures in the rewinding of yarn for the apparel industry by the firm Liconfe, from Barcelos, Portugal. Due to the large variety of products, i.e. yarns of many colors, the actual approach of the firm to production and inventory towards satisfying demand was critically analyzed. The firm policy of offering a high service level, with as much as possible immediate deliveries, led to the make-to-stock approach of every colour with an identical treatment for all colours as far stock levels and related production orders are concerned. In spite of this, frequently customer orders could not be met due to frequent stock outs, amplified by the highly variable delivery time of the dyeing service that would make deliveries of rewinding yarn late or lost. The study developed an approach to improve management towards meeting firm objectives of high service levels and reduced costs of inventory and production. In order to reduce the complexity of the analysis, and get useful results in time made available the option of treating only the polyester yarn, having a high contribution, about 80% to the company's sales, thereby reducing the range references analysis for approximately one thousand. The logical step was to develop and propose an approach to management that took account of the behavior differences on demand of the different products. An ABC analysis clearly identified the 20% of products that accounted for 70% of the sales, i.e. the class A products, and also the B and C classes. The C class constitute the largest range more than 50% of the color, but were found to have a small contribution in sales, between 9% to 10%. The management approach proposed combined MTS and MTO in several ways dependent on the class where the products felled, A, B or C. For every class A product was established a reorder level, dependent both on demand and the reasonable time, slightly above average, actually 15 days, to get the dyeing service done. The amount of production or raw yarn to dye, every time production was needed, also varied according to demand. The aim was to avoid stock outs without exaggerated inventory levels, ensuring very high service level of products of the class A. Products of class B were also proposed to be made to stock, and exceptionally to order if when a customer order arrives no inventory is available, as was done for class A products. The great difference is that in general a much lower inventory level was kept for B class products and reorder levels didn’t practically vary for products within class B. It is worth to mention that, due to the very flexible and fast rewinding process and the existence of about a hundred of rewinding heads, customer orders of average size, for any product, could be met in a matter of minutes. Because of this and the infrequent ordering of class C products, these were proposed to be made to order, when this is required. When this was made, due to the minimum amount of 35kg of yarn dyeing service, this amount was rewound, whenever no stock was available. Yarn not sold, after the order was delivered, was kept in inventory. The methodology was proven to have a great potential to improve the delivery service level and reduce costs of both production and inventory in relation to the actual situation in the firm. The work also proposed and implemented an arrangement of the inventory areas in order to reduce waste of time and energy manipulation of transport of the sets of dyed bobbins for rewinding. It was also concluded that the use of the production hybrid MTS-MTO, coupled with dynamically updated analysis of the ABC classification of items, is a strategy that tends to reduce disruptions of stock relative to sales volume and thus improve the quality of service of the company, thereby improving customer satisfaction