Abstract
The incidence of colorectal cancer cases in the Portuguese Institute of Oncology of Porto created the need of a telenursing program in the Gastro-Intestinal Cancer Unit. After staging, treatment may involve surgery radio and chemotherapy (either oral or IV). Patients with no treatment after surgery are scheduled for medical exams every 3 months in the first 2 years. Patients on chemotherapy need to be compliant and to have a close monitoring of adverse events. The GI Cancer Unit uses a telenursing information system to help assess colorectal cancer patients' follow-up after surgery, medical treatment compliance and adverse events. A mixed-methods evaluation was done to a) describe the target population, b) detect problems in the telenursing information system, and c) suggest changes to meet users' requirements. From 181 outbound phone calls, representing 67 patients (49 in treatment and 18 in follow-up), patients' main characteristics were extracted and system's problems were identified by the intervening nurses. Recommendations will be useful for a further development of the system.

Abstract
This research intends to reduce energy consumption in a plastic film industrial unit. Trough the development of a new energy model focused on self renewable energy production and energy management in some sectors, such as lighting and compressed air. It is expected that this model leads to energy savings with environmental advantages (lower greenhouse gases emission). This may grant access to eco-sustainable certifications/awards as a factor of competitiveness, as well as economic benefits. The methodology followed to design the new energy model was developed from an energy audit to characterize the existing consumptions and use of energy.

Abstract
In this work we study the impact of a set of bag-of-features strategies for the recognition of cancer in gastroenterology images. By using the SIFT descriptor, we analyzed the importance and performance impact of term weighting functions for the construction of visual vocabularies. Further analyzes were conducted in order to ascertain the robustness of multiclass decomposition rules for Support Vector Machines with different kernels. Our study was extended by tailoring a decomposition rule that explores prior knowledge according the four grades of the Singh taxonomy (SDR). We found that SDR coupled with a frequency term weight function attained the best overall results (80%) when trained with an intersection kernel. It also outperformed standard decomposition rules when using a chi(2) kernel and attained competitive performances with a linear kernel.

Abstract
In food supply chain planning, the trade-off between expected profit and risk is emphasized by the perishable nature of the goods that it has to handle. In particular, the risk of spoilage and the risk of revenue loss are substantial when stochastic parameters related to the demand, the consumer behavior, and the spoilage effect are considered. This paper aims to expose and handle this trade-off by developing risk-averse production planning models that incorporate financial risk measures. In particular, the performance of a risk-neutral attitude is compared to the performance of models taking into account the upper partial mean and the conditional value-at-risk. Insights from an illustrative example show the positive impact of the-risk-averse models in operational performance indicators, such as the amount of expired products. Furthermore, through an extensive computational experiment, the advantage of the conditional value-at-risk model is evidenced, as it is able to dominate the solutions from the upper partial mean for the spoilage performance indicator. These advantages are tightly related to a sustainable view of production planning, and they can be achieved at the expense of controlled losses in the expected profit.

Abstract

Abstract
Underwater wireless communication systems are becoming a priority in terms of research and technological development due to the increasing demand for exploring the oceans’ potential in areas such as pharmaceutical, oil, minerals, environmental and biodiversity. This demand is increasing exponentially with the need for high data rate and near-real-time communications between submerged mobile and static agents. The existing wireless communication technologies using electromagnetic waves or lasers are not very efficient due to the large attenuation in aquatic environment. Ultrasound reveals a lower attenuation, and thus has been used in underwater long-distance communications. But the underwater acoustic medium is one of the less reliable communication channels which represent major challenges for communications. With relatively slow sound speed propagation (~1500 m/s) the delay may represent a problem for communications with real-time applications. A theoretical model of an underwater communication system was also developed. The model allows to emulate the emitter, the hydrophone and the underwater acoustic channel, which includes attenuation, environmental noise, Doppler Effect, multipath and propagation delay. This model supported the study of wireless communications by emulating the transmission of acoustic signals using different types of digital modulations. The acoustic signal attenuation, multipath, ambient noise in several environments theoretical results were compared to those obtained experimentally. Allowing to conclude that the model represents a suitable approximation to the real subaquatic communication channel for the evaluation of digital acoustic communications. An optimization study of ultrasound transducers for underwater communications was addressed, focusing on a piston type emitter operating in the thickness mode (d33). It was discussed how the acoustic impedance, thickness, resonance frequency and structure affect the transducer performance. This work allowed a better understanding of the emitter transducer characteristics allowing reaching the optimum point of operation for specific applications. Focusing on underwater communication, the transducer was optimized by finite element computer simulations. The results were compared with experimental tests and show that four-layer structures increase up to 16 dB in performance when compared to single-layer transducer disks. For high data-rates and real-time applications it was necessary to develop ultrasound transducers able to work at high frequencies and wideband, with suitable responses to digital modulations. It was thus also included a comparison study that shows how the acoustic impedance influences the performance of an ultrasonic emitter when using different digital modulations and operating at frequencies between 100 kHz and 1 MHz and some tens of meters of distance. It is presented a Finite Element Method (FEM) and a MATLAB/Simulink simulation with an experimental validation to evaluate two types of piezoelectric materials: one based in ceramics (high acoustic impedance) with a resonance design and a polymer based (low acoustic impedance) system, designed to optimize the performance when using digital modulations. The transducers performance for Binary Amplitude Shift Keying (BASK), On-Off Keying (OOK), Binary Phase Shift Keying (BPSK) and Binary Frequency Shift Keying (BFSK) modulations with a 1 MHz carrier at 125 kbps baud rate were compared. The transducers materials used were the ceramics PZT-5H and the polymer PVDF. The results show that PVDF transducer has a better performance to digital modulations than PZT-5H transducer, providing the signal full demodulation for all digital modulations tested. On the other hand, the PZT-5H transducer showed a higher output, but fails to perform accurate modulated signals. Finally, the system was validated by the implementation of a full duplex point-to-point communication at 1 Mbps using OOK modulation with a 1 MHz single carrier. The system was successfully tested in a swimming pool at a distance of 6 meters with a 1 Mbps rate, achieving a 3x10-3 Bit Error Rate (BER) using just 1.4 W of power consumption. These results represent an advance in underwater acoustic communications, being the first practical system to achieve data rates up to 1 Mbps.;O desenvolvimento de sistemas de comunicação subaquáticos sem fios está a tornar-se uma prioridade na comunidade científica no sentido de aumentar o desenvolvimento tecnológico. Este facto deve-se à crescente necessidade de exploração do potencial dos oceanos em áreas científicas diversas como farmacêutica, petrolífera, mineral, ambiental e até do próprio estudo da biodiversidade. Essa necessidade aumenta exponencialmente com a necessidade de comunicações de alto débito e em tempo real entre agentes submersos móveis e estáticos. As tecnologias de comunicações sem fios existentes, nomeadamente as que utilizam ondas eletromagnéticas ou lasers não são muito eficientes, devido, em grande parte, à atenuação no ambiente subaquático. Os ultrassons revelam uma menor atenuação tendo sido, por isso, utilizados em comunicações subaquáticas em longas distâncias. Contudo o canal acústico subaquático definisse como um dos mais difíceis, devido em parte as suas características únicas, o que apresenta ser um enorme desafio. Como a velocidade de propagação do som é relativamente lenta (~1500 m/s), o atraso pode representar um problema para as aplicações em tempo real. Foi desenvolvido um modelo teórico do sistema de comunicações subaquáticos que permite emular o emissor, o hidrofone e o canal acústico subaquático. No canal acústico subaquático foi simulado o efeito da atenuação, ruído ambiente, efeito de Doppler, multipath e atraso de propagação. Este modelo é indicado para o estudo das comunicações subaquáticas, emulando a transmissão de sinais acústicos utilizando diferentes tipos de modulações digitais. Neste estudo foram testados, a atenuação do sinal acústico, multipath, ruído em diversos ambientes e os resultados teóricos foram comparados com os obtidos experimentalmente. Permitindo concluir que o modelo representa uma aproximação adequada do canal de comunicação, permitindo a avaliação das comunicações digitais acústicas. Inclui ainda um estudo de otimização de transdutores de ultrassons para comunicações subaquáticos, tendo como base o emissor do tipo pistão, operando ao longo da espessura (d33). Foi analisada ainda a forma como a impedância, espessura, frequência de ressonância acústica e estrutura afetam o desempenho do transdutor. Este trabalho permitiu uma melhor compreensão das características do transdutor emissor que permitem atingir o ponto ótimo de operação para aplicações específicas. Tendo como base a comunicação subaquática, o transdutor foi otimizado usando os resultados de simulações pelo Método dos Elementos Finitos. Os resultados foram comparados com os testes experimentais, onde se mostra que as estruturas de quatro camadas podem aumentar até 16dB no desempenho quando comparados com discos de transdutor de única camada. Para aplicações em tempo real e de elevado debito, foi necessário desenvolver transdutores de ultrassons capazes de operar em banda larga a altas frequências, com resposta adequada às modulações digitais. Foi, portanto, incluído também um estudo comparativo que mostra como a impedância acústica influencia o desempenho do emissor de ultrassons quando se utilizam modulações digitais a operar com frequências entre 100 kHz e 1 MHz abrangendo distâncias de algumas dezenas de metros. São apresentadas simulações por Método de Elementos Finitos (MEF) e MATLAB/Simulink com validação experimental de modo a avaliar dois tipos de materiais piezoelétricos: um com base cerâmica PZT-5H (alta impedância acústica) com um design de ressonância e outro de base de polimérica PVDF (baixa impedância acústica), otimizado para modulações digitais. O desempenho dos transdutores foi comparado para as modulações: Binary Amplitude Shift Keying (BASK), On-Off Keying (OOK), Binary Phase Shift Keying (BPSK) e Binary Frequency Shift Keying (BFSK) com uma portadora de 1 MHz a 125 kbps. Os resultados mostram que o transdutor de PVDF tem um melhor desempenho do que transdutor PZT-5H, proporcionando a desmodulação completa do sinal para todas as modulações digitais testadas. Por outro lado, o transdutor de PZT-5H mostrou uma potência acústica mais elevada, embora não consiga produzir sinais modulados precisos. Finalmente, o sistema foi validado através da implementação de uma comunicação ponto-aponto bidirecional de 1 Mbps utilizando uma modulação OOK com uma portadora de 1 MHz. O sistema foi testado com sucesso numa piscina a uma distância de 6 metros com uma taxa de 1 Mbps, com um BER (Bit Error Rate) de 3x10-3, utilizando apenas 1,4 W de consumo de potência. Estes resultados representam um avanço nas comunicações acústicas subaquáticas, sendo o primeiro sistema prático de atingir velocidades até 1 Mbps.