Percorrer por autor "Almeida, Ana"
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- Abordagens ao Problema de Escalonamento em Ambientes Reais de ProduçãoPublication . Madureira, Ana Maria; Almeida, Ana[Resumo] Num sistema de fabrico do tipo Job-Shop podem ser identificados alguns factores que contribuem para a dificuldade do processo de escalonamento, nomeadamente, a complexidade, as restrições e a incerteza. Os ambientes industriais reais são sujeitos a várias fontes de mudança, as quais são tratadas como ocorrências aleatórias, tais como, lançamento de novas ordens de fabrico, avarias, alterações de prioridades, atrasos nas operações, etc. Por escalonamento dinâmico consideramos a situação na qual um plano flexível é executado, isto é, o plano inicial é dinamicamente ajustado (re-escalonado) sempre que eventos inesperados ocorrem no sistema. Esta comunicação tem por objectivo principal efectuar uma sistematização de conceitos e classificações de problemas e tipos de escalonamento, bem como das abordagens usadas na sua resolução. Inicialmente, é apresentado o problema de escalonamento, através da caracterização dos seus elementos e da referência a algumas definições encontradas na literatura, A seguir descrevem-se algumas classificações para os problemas de escalonamento e os tipos de abordagens de resolução a adoptar. Finalmente, são propostas duas arquitecturas para a resolução do problema de escalonamento em ambientes reais de produção caracterizados por um elevado grau de dinamismo. À primeira baseada em Sistemas de Apoio à Decisão e a segunda em Algoritmos Genéticos.
- AIRDOC: Smart mobile application for individualized support and monitoring of respiratory function and sounds of patients with chronic osbtructive diseasePublication . Almeida, Rute; Amaral, Rita; Jácome, Cristina; Martinho, Diogo; Vieira-Marques, Pedro; Jacinto, Tiago; Ferreira, Ana; Almeida, Ana; Martins, Constantino; Pereira, Mariana; Pereira, Ana; Valente, José; Almeida, Rafael; Vieira, Ana; Amaral, Rita; Sá-Sousa, Ana; Gonçalves, Ivânia; Rodrigues, Pedro; Alves-Correia, Magna; Freitas, Alberto; Marreiros, GoretiCurrent tools for self-management of chronic obstructive respiratory diseases (CORD) are difficult to use, not individualized and requiring laborious analysis by health professionals, discouraging their use in healthcare. There is an opportunity for cost-effective and easy-to-disseminate advanced technological solutions directed to patients and attractive to different stakeholders. The strategy of AIRDOC is to develop and integrate self-monitoring and self-managing tools, making use of the smartphone's presence in everyday life. AIRDOC intends to innovate on: i) technologies for remote monitoring of respiratory function and computerized lung auscultation; ii) coaching solutions, integrating psychoeducation, gamification and disease management support systems; and iii) management of personal health data, focusing on security, privacy and interoperability. It is expected that AIRDOC results will contribute for the innovation in CORD healthcare, with increased patient involvement and empowerment while providing quality prospective information for better clinical decisions, allowing more efficient and sustainable healthcare delivery.
- Creating and optimizing client-server applications on mobile devicesPublication . Anacleto, Ricardo; Luz, Nuno; Almeida, Ana; Figueiredo, Lino; Novais, PauloMobile devices are embedded systems with very limited capacities that need to be considered when developing a client-server application, mainly due to technical, ergonomic and economic implications to the mobile user. With the increasing popularity of mobile computing, many developers have faced problems due to low performance of devices. In this paper, we discuss how to optimize and create client-server applications for in wireless/mobile environments, presenting techniques to improve overall performance.
- Dynamic scheduling of manufacturing orders: A decision support system approachPublication . Almeida, Ana; Ramos, Carlos; Silva, S. D. C.This paper presents a decision support system (DSS) based architecture and a new method for the dynamic scheduling of manufacturing systems. The proposed architecture is based on the DSS paradigm. The typical scheduling problems, namely the order allocation and order sequencing problems, are to be solved for a given production plan which defines a set of manufacturing orders to be processed. These specify product types to be manufactured, their quantities and due dates. The allocation problem deals with the assignment of n orders to m manufacturing processors, under the given production plan, and the solution to the sequencing problem identifies the input sequence and the instants of processing of the assigned orders on each manufacturing processor.
- Energy and exergy analysis of co-gasification of crude glycerol and animal fat mixturesPublication . Almeida, Ana; Pilão, Rosa Maria; Ramalho, Elisa; Pinho, CarlosThis work presents an energy and exergy analysis of co-gasification tests of crude glycerol and animal fat mixtures, in order to obtain first and second law efficiencies, the last ones representing a novelty in the field of gasification technology. Mixtures with 5% (w/w) of dry animal fat, 57% (w/w) of dry treated crude glycerol and 38% (w/w) of water were studied in a fixed bed down flow gasification reactor at 800°C and 900°C. The increase of gasification temperature seems not to affect the energy and exergy yields of the overall process.
- Frequency of TERT promoter mutations in human cancersPublication . Vinagre, João; Almeida, Ana; Pópulo, Helena; Batista, Rui; Lyra, Joana; Pinto, Vasco; Coelho, Ricardo; Celestino, Ricardo; Prazeres, Hugo; Lima, Luís; Melo, Miguel; Rocha, Adriana Gaspar; Preto, Ana; Castro, Patrícia; Castro, Ligia; Pardal, Fernando; Lopes, José Manuel; Santos, Lúcio; Reis, Rui Manuel; Cameselle-Teijeiro, José; Sobrinho-Simões, Manuel; Lima, Jorge; Máximo, Valdemar; Soares, PaulaReactivation of telomerase has been implicated in human tumorigenesis, but the underlying mechanisms remain poorly understood. Here we report the presence of recurrent somatic mutations in the TERT promoter in cancers of the central nervous system (43%), bladder (59%), thyroid (follicular cell-derived, 10%) and skin (melanoma, 29%). In thyroid cancers, the presence of TERT promoter mutations (when occurring together with BRAF mutations) is significantly associated with higher TERT mRNA expression, and in glioblastoma we find a trend for increased telomerase expression in cases harbouring TERT promoter mutations. Both in thyroid cancers and glioblastoma, TERT promoter mutations are significantly associated with older age of the patients. Our results show that TERT promoter mutations are relatively frequent in specific types of human cancers, where they lead to enhanced expression of telomerase.
- Gasification of crude glycerol after salt removalPublication . Almeida, Ana; Pilão, Rosa; Ribeiro, A.M.; Ramalho, Elisa; Pinho, CarlosThe increase in the amount of crude glycerol available on the market, as well as the decrease in its purity due to the use of waste materials in the production of biodiesel, has forced producers to look for alternative ways of valuing this byproduct. In this research work, crude glycerol of a Portuguese biodiesel producer was pretreated using an ion exchange process in order to reduce its salt content. The gasification process was performed using steam as the oxidizing agent in a down-flow fixed-bed reactor using alumina particles as bed material. After the gasification process, the producer gas flowed through a condensing and cleaning system, in order to remove the condensable fraction. Dry gas samples were collected and analyzed by GC in order to quantify the CO, CO2, CH4, and H2 content. Three different feed mixtures were studied with 35%, 39%, and 59% (w/w) water, and the tests were performed at 850, 900, and 950 °C. The results showed that the increase of the water content in the feed mixture led to higher values of H2 and CO2, and lower values for CO and CH4, on the producer gas composition. A slight increase of dry gas yield and hydrogen conversion efficiency with the increase of water content in the feed was observed, while the lower heating value of producer gas decreased. No significant influence of water content was detected in the carbon conversion efficiency and cold gas efficiency. The increase of temperature resulted in the increase of four gasification parameters with maximum mean values of 90% for carbon conversion efficiency, 100% for hydrogen conversion efficiency, 107% for cold gas efficiency, and 1.3 m3/kg raw material. The maximum lower heating value of 14.5 MJ/m3 was obtained at 850 °C.
- Geo-localization System for People with Cognitive DisabilitiesPublication . Ramos, João; Anacleto, Ricardo; Novais, Paulo; Figueiredo, Lino; Almeida, Ana; Neves, JoséTechnology is present in almost every simple aspect of the people’s daily life. As an instance, let us refer to the smartphone. This device is usually equipped with a GPS modulewhich may be used as an orientation system, if it carries the right functionalities. The problem is that these applications may be complex to operate and may not be within the bounds of everybody. Therefore, the main goal here is to develop an orientation system that may help people with cognitive disabilities in their day-to-day journeys, when the caregivers are absent. On the other hand, to keep paid helpers aware of the current location of the disable people, it will be also considered a localization system. Knowing their current locations, caregiversmay engage in others activities without neglecting their prime work, and, at the same time, turning people with cognitive disabilities more independent.
- A hybrid recommendation approach for a tourism systemPublication . Lucas, Joel P.; Luz, Nuno; Moreno, María; Anacleto, Ricardo; Almeida, Ana; Martins, ConstantinoMany current e-commerce systems provide personalization when their content is shown to users. In this sense, recommender systems make personalized suggestions and provide information of items available in the system. Nowadays, there is a vast amount of methods, including data mining techniques that can be employed for personalization in recommender systems. However, these methods are still quite vulnerable to some limitations and shortcomings related to recommender environment. In order to deal with some of them, in this work we implement a recommendation methodology in a recommender system for tourism, where classification based on association is applied. Classification based on association methods, also named associative classification methods, consist of an alternative data mining technique, which combines concepts from classification and association in order to allow association rules to be employed in a prediction context. The proposed methodology was evaluated in some case studies, where we could verify that it is able to shorten limitations presented in recommender systems and to enhance recommendation quality.
- Lightweight user modeling – a case studyPublication . Luz, Nuno; Anacleto, Ricardo; Martins, Constantino; Almeida, AnaIn the context of previous publications, we propose a new lightweight UM process, intended to work as a tourism recommender system in a commercial environment. The new process tackles issues like cold start, gray sheep and over specialization through a rich user model and the application of a gradual forgetting function to the collected user action history. Also, significant performance improvements were achieved regarding the previously proposed UM process.
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