Recursos de colección

Repositório do Instituto Politénico de Castelo Branco (14.183 recursos)

O Repositório Científico do Instituto Politécnico de Castelo Branco tem como objectivos fundamentais a divulgação, a preservação em formato digital e a partilha do conhecimento científico gerado na instituição, constituindo-se numa ferramenta de valor acrescentado porque permite aumentar a visibilidade e o impacto da investigação desenvolvida.

ESTCB - Escola Superior de Tecnologia

Mostrando recursos 1 - 20 de 414

  1. Computational intelligence applied to discriminate bee pollen quality and botanical origin

    Gonçalves, P.J.S.; Estevinho, L.M.; Pereira, A.P.; Sousa, J.M.C.; Anjos, O.
    The aim of this work was to develop computational intelligence models based on neural networks (NN), fuzzy models (FM), and support vector machines (SVM) to predict physicochemical composition of bee pollen mixture given their botanical origin. To obtain the predominant plant genus of pollen (was the output variable), based on physicochemical composition (were the input variables of the predictive model), prediction models were learned from data. For the inverse case study, input/output variables were swapped. The probabilistic NN prediction model obtained 98.4% of correct classification of the predominant plant genus of pollen. To obtain the secondary and tertiary plant genus...

  2. Estudo empírico do desempenho dos modelos de gestão de filas FIFO, WFQ e CBWFQ em sistemas reais

    Sousa, Celso; Fonte, Alexandre
    As aplicações multimédia (e.g., voz ou vídeo) exigem às redes IP um serviço de comunicação com baixa latência, baixas taxas de perdas de pacotes, e requisitos mínimos de largura de banda. Diferentes arquiteturas de Qualidade de Serviço (QoS) foram propostas e desenvolvidas por dois grupos do IETF, o modelo IntServ e o modelo, um pouco mais recente, DiffServ. Os fabricantes de equipamento de rede adotaram as suas próprias implementações destes modelos nos seus equipamentos de encaminhamento IP ou de comutação multicamada, para além do modelo Best-Effort. Neste trabalho, pretende-se avaliar a eficácia da implementação DiffServ realizada por um dos principais...

  3. Multiview real-time media distribution for next generation networks

    Marques, Hugo; Silva, Hélio; Logota, Evariste; Rodriguez, Jonathan; Vahid, Seiamak; Tafazolli, Rahim
    With the massive deployment of broadband access to the end-users, the continuous improvement of the hardware capabilities of end devices and better video compression techniques, acceptable conditions have been met to unleash over-the-top bandwidth demanding and time-stringent P2P applications, such as multiview real-time media distribution. Such applications enable the transmission of multiple views of the same scene, providing consumers with a more immersive visual experience. This article proposes an architecture to distribute multiview real-time media content using a hybrid DVB-T2, client-server and P2P paradigms, supported by an also novel QoS solution. The approach minimizes packet delay, interar- rival jitter, inter-ISP...

  4. Multiview real-time media distribution for next generation networks

    Marques, Hugo; Silva, Hélio; Logota, Evariste; Rodriguez, Jonathan; Vahid, Seiamak; Tafazolli, Rahim
    With the massive deployment of broadband access to the end-users, the continuous improvement of the hardware capabilities of end devices and better video compression techniques, acceptable conditions have been met to unleash over-the-top bandwidth demanding and time-stringent P2P applications, such as multiview real-time media distribution. Such applications enable the transmission of multiple views of the same scene, providing consumers with a more immersive visual experience. This article proposes an architecture to distribute multiview real-time media content using a hybrid DVB-T2, client-server and P2P paradigms, supported by an also novel QoS solution. The approach minimizes packet delay, interar- rival jitter, inter-ISP...

  5. A numerical study of the effect of single overloads on plasticity induced crack closure

    Baptista, J.B.; Antunes, F.V.; Correia, L.; Branco, R.
    In this work, the effect of single overloads on plasticity induced crack closure is studied. An elastic-plastic finite element model was developed and the crack opening level was calculated from the contact forces along the crack flank. The effects of the loading parameters and stress state are analysed, and the mechanisms behind crack closure variations are identified. An overload is a traumatic event that eliminates material’s memory relative to the load history. Crack tip blunting is the mechanism behind this memory loss, since it eliminates crack closure. Material hardening has a major relevance on the evolution of plastic blunting, which was evident in the variation of...

  6. A numerical study of the effect of single overloads on plasticity induced crack closure

    Baptista, J.B.; Antunes, F.V.; Correia, L.; Branco, R.
    In this work, the effect of single overloads on plasticity induced crack closure is studied. An elastic-plastic finite element model was developed and the crack opening level was calculated from the contact forces along the crack flank. The effects of the loading parameters and stress state are analysed, and the mechanisms behind crack closure variations are identified. An overload is a traumatic event that eliminates material’s memory relative to the load history. Crack tip blunting is the mechanism behind this memory loss, since it eliminates crack closure. Material hardening has a major relevance on the evolution of plastic blunting, which was evident in the variation of...

  7. Caraterização de patologias do património edificado da cidade de Castelo Branco: diagnóstico e intervenção

    Costa, Cátia de Jesus Simão Dias
    Relatório de Estágio apresentado à Escola Superior de Tecnologia do Instituo Politécnico de Castelo Branco para cumprimento dos requisitos necessários à obtenção do grau de Mestre em Construção Sustentável, realizado sob orientação científica da Professora Doutora Cristina Calmeiro dos Santos, do Instituto Politécnico de Castelo Branco.

  8. Caraterização de patologias do património edificado da cidade de Castelo Branco: diagnóstico e intervenção

    Costa, Cátia de Jesus Simão Dias
    Relatório de Estágio apresentado à Escola Superior de Tecnologia do Instituo Politécnico de Castelo Branco para cumprimento dos requisitos necessários à obtenção do grau de Mestre em Construção Sustentável, realizado sob orientação científica da Professora Doutora Cristina Calmeiro dos Santos, do Instituto Politécnico de Castelo Branco.

  9. Affordable LTE network benchmarking based on transport fleets

    Dionísio, Rogério; Marques, Paulo; Marques, Hugo; Alves, Tiago; Pereira, Luís; Silva, Fernando; Ribeiro, Jorge
    “© 2017 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.”

  10. Affordable LTE network benchmarking based on transport fleets

    Dionísio, Rogério; Marques, Paulo; Marques, Hugo; Alves, Tiago; Pereira, Luís; Silva, Fernando; Ribeiro, Jorge
    “© 2017 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.”

  11. Real-time tourists counting and tracking system for management of nature trails in naturtejo global geopark (Portugal)

    Dionísio, Rogério; Marques, Paulo; Silva, F.P.; Rodrigues, J.; Carvalho, C.N.
    This paper presents a counting system project for the Naturtejo Global Geopark, which is structured in two phases. The objective of the first phase was to develop, install and test an electronic system able to remotely count the number of visitors on the Naturtejo Geopark walking routes and touristic sites. The data is reported through a web interface. A Pilot test is currently installed on Trail PR3 – “Fossil’s Route”, near the village of Penha Garcia. Since May 2015, more than 6000 tourists where monitored. The second phase of the project aims to track tourists based on the detection of...

  12. Experimental analysis of building airtightness in traditional residential portuguese buildings

    Salehi, Atefeh; Torres, Isabel; Ramos, A.T.V.F.
    It is currently recognized that the residential building sector is one of the largest energy consumers in the world. The energy crisis of the 1970s was important for drawing attention to the subject of energy consumption and the necessity to save energy. The airtightness of buildings is an important factor affecting a building’s energy consumption and also energy-saving potential. On the other hand, the ventilation rate has also a significant effect on indoor air quality and is assumed to be an essential criterion of a building’s performance. However, most of the existing research in this area has been developed in...

  13. Computing the thermal energy performance of building by virtue of building dimensional typology

    Salehi, Atefeh; Torres, Isabel; Ramos, A.T.V.F.
    The constructive particularities of Portuguese old buildings, with specific and ancient constructive solutions and buildings’ aesthetics, determine the type of interventions and turn some of the most efficient interventions impossible to apply. Since the external appearance of buildings in old city centers must be preserved, nor is the use of external isolation not an alternative, neither the use of materials with low hygro-scopicity, due to the nature of the material used in exterior walls, usually stone. Presented research was expanded to figure out the reaction of different intervention solutions which are used in old buildings’ envelope to accomplish their energy...

  14. An analytical approach to the ventilation effectiveness of mediterranean buildings: case study: existing residential building, Portugal

    Salehi, Atefeh; Torres, Isabel; Ramos, A.T.V.F.
    Building airtightness assumes an important role in the energy saving and the indoor thermal comfort. Ventilation rates bring significant impacts on energy usage in the constructions and indoor contaminant concentrations and also setting them as the key parameters in building performance. Ventilation rate have been measured in building for a long time, and there are some developed measurement methodologies related to it in the research domains. However, most of the investigations in recent years have been done usually in the cold climate conditions, while Mediterranean construction are not deeply investigated in the literature. In this paper, the authors present the...

  15. Developing a new bayesian risk index for risk evaluation of soil contamination

    Albuquerque, M.T.D.; Gerassis, S.; Sierra, C.; Taboada, J.; Martín, J.E.; Antunes, I.M.H.R.; Gallego, J.R.
    Industrial and agricultural activities heavily constrain soil quality. Potentially Toxic Elements (PTEs) are a threat to public health and the environment alike. In this regard, the identification of areas that require remediation is crucial. In the herein research a geochemical dataset (230 samples) comprising 14 elements (Cu, Pb, Zn, Ag, Ni, Mn, Fe, As, Cd, V, Cr, Ti, Al and S) was gathered throughout eight different zones distinguished by their main activity, namely, recreational, agriculture/livestock and heavy industry in the Avilés Estuary (North of Spain). Then a stratified systematic sampling method was used at short, medium, and long distances from...

  16. Assessment of ventilation effectiveness in exiting residential building in mediterranean countries: case study, existing residential building in Portugal

    Salehi, Atefeh; Torres, Isabel; Ramos, A.T.V.F.
    Natural ventilation as a part of a buildinǵs function that has a strong effect on human comfort. The reduction of natural ventilation and infiltration, as a part of the ventilation system in the old existing buildings, due to intervention actions, have been causing a reduction in indoor air quality and an increment of relative humidity levels in the indoor environment. Providing optimal indoor condition is not only related to the renewal of the air but also with its distribution. Hence airflow patterns in historical buildings influence interior comfort conditions. The aim of this work is to assess the effectiveness of the...

  17. Improving performance in POLCA controlled high variety shops: an assessment by simulation

    Thürer, Matthias; Fernandes, N.O.G.; Carmo-Silva, Sílvio; Stevenson, Mark
    POLCA (i.e. Paired-cell Overlapping Loops of Cards with Authorization) is a card-based production control approach developed to support the adoption of Quick Response Manufacturing. The approach has received significant research attention but has remained largely unchanged since its introduction in the late 1990s. The main improvements have occurred in the context of an electronic POLCA system, but such developments undermine the simplicity of the original card-based concept. We ask: is there any refinement possible to enhance the performance of POLCA without jeopardizing its simplicity? By analyzing POLCA, two possible refinements are identified: (i) the choice of rule to support both...

  18. On the backlog-sequencing decision for extending the applicability of ConWIP to high-variety contexts: an assessment by simulation

    Thürer, Matthias; Fernandes, N.O.G.; Stevenson, Mark; Qu, Ting
    Constant Work-in-Process (ConWIP) is a card-based control system that was developed for simple flow shops – a lack of load-balancing capabilities hinders its application to more complex shops. In contrast, load balancing is an integral part of Workload Control, a production planning and control concept developed for high-variety environments. One means of load balancing evident in the Workload Control literature is through the use of a capacity slack-based backlog-sequencing rule. This study therefore investigates the potential of the backlog-sequencing decision to improve load balancing in the context of ConWIP, thereby making it suitable for more complex, high-variety environments. Using simulation,...

  19. Improving workload control order release: incorporating a starvation avoidance trigger into continuous release

    Fernandes, N.O.G.; Thürer, Matthias; Silva, Cristóvão; Carmo-Silva, Sílvio
    Order release is a key component of Workload Control - a production planning and control system that aims at balancing workloads across workstations, while ensuring the timely release of jobs (or orders) to the shop floor in order to meet due dates. Several release methods have been proposed and evaluated in the WLC literature. A major criterion to distinguish between release methods is whether they take the release decision at periodic time intervals or continuously. This paper aims at improving WLC order release by incorporating a starvation avoidance trigger into continuous release. Using simulation, we demonstrate that significant performance improvements...

  20. Model for and integrates evaluation of rehabilitation actions:an approach to a group of buildings of the beginning of the 20th century

    Mouraz, Catarina P.; Silva, José Mendes; Ramos, A.T.V.F.; Bettencourt, António A.
    The current challenges of sustainable construction are frequently deemed incompatible or hardly reconcilable with the basic principles of heritage safeguarding and conservation. This issue may gradually be surpassed with a thorough integrated analysis of the rehabilitation solutions and a detailed knowledge of the existing building. This paper presents the application of an exploratory model for an integrated evaluation of rehabilitation actions according to different perspectives, such as local regulatory demands as well as sustainable heritage preservation concerns. The design of this approach was based on a constructive characterization and conservation state analysis of three city blocks located in the Historical...

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