Repository logo

Browsing by Issue Date, starting with "2020-10-12"

Filter results by year or month
Now showing 1 - 5 of 5
  • Optimal distribution of active piezoelectric elements for noise attenuation in sandwich panels
    Publication . Madeira, JFA; Araújo, A. L.
    In this paper, a multiobjective optimization approach for obtaining the optimal distribution of surface-bonded piezoelectric sensors and actuators for noise attenuation in sandwich panels is presented. The noise attenuation is achieved by using negative velocity feedback control with co-located sensors and actuators. The control gains are also optimized in order to obtain the most efficient noise attenuation in a given frequency band. An in-house implementation of a viscoelastic soft core sandwich plate finite element, including surface-bonded piezoelectric sensors and actuators with active control capabilities, is used for obtaining the frequency response of the panels. The sound transmission capability of the panels is evaluated using the radiated sound power, along with the Rayleigh integral approach, which is suitable for lightly coupled structural/acoustic problems. The Direct MultiSearch (DMS) optimization algorithm is used to minimize the added weight due to the piezoelectric material, minimizing also the number of required controllers and maximizing the noise attenuation. The total length of the radiated sound power curve is shown to be an effective measure of noise attenuation in a given frequency band. Trade-off Pareto fronts and the obtained optimal configurations are presented and discussed.
    2020-10-12Journal article Open access Show more
  • Carpooling : agregador de sistemas de boleias
    Publication . Moura, Rodrigo Diniz de; Filipe, Porfírio Pena
    Os sistemas inteligentes de transporte são aplicações informáticas avançadas que suportam requisitos inovadores relacionados com os diferentes modos de transporte. Estas aplicações são vitais para atenuar o congestionamento de tráfego urbano e consequentes questões ambientais tornando os transportes mais eficazes e sustentáveis. Neste contexto, surge a noção de sistema de boleias, do inglês Carpooling System, que pode ser descrito como um facilitador da partilha de lugares disponíveis num veículo particular que realiza uma determinada viagem. O objetivo desta dissertação, intitulada Agregador de Sistemas de Boleias, é delinear a arquitetura de um agregador de sistemas de boleias que virtualizam a existência de comunidades restritas de viajantes, do inglês Carpool Clubs, com regras de agregação estabelecidas por um acordo previamente negociado. Neste âmbito, o agregador emerge como um facilitador da organização de sistemas de boleias, com administrações próprias que gerem autonomamente admissões, recompensas e penalizações, mantendo a privacidade e a confiança entre o seu grupo restrito de viajantes. Para o efeito, propõe-se que o agregador adote uma arquitetura descentralizada e baseada em serviços. A avaliação experimental desta arquitetura foi realizada desenvolvendo e instalando um demonstrador que agrega sistemas de boleias, que unificam e melhoram os requisitos mais comuns presentes no mercado, destacando a privacidade e a confiança dos utilizadores.
    2020-10-12Master thesis Open access Show more
  • Comunicação de risco em contexto municipal: Reflexões preliminares
    Publication . Nunes, Mariana; Pereira, Sandra Cristina Martins
    Os contornos da atual realidade – global e isenta de fronteiras - onde o digital revolucionou relações interpessoais e noção de distância, democratizando o acesso ao conhecimento e melhorando a vida dos indivíduos, lançaram a sociedade num drama enraizado na sua própria atividade tecnocientífica, cujo estado normal ameaça tornar-se catastrófico, dado o seu caráter de vulnerabilidade, incerteza, complexidade e ambiguidade, e originando a denominada ‘sociedade de risco’.Neste paradoxo, reside a pertinência em estudar num contexto municipal o fluxo comunicacional, assim como os mecanismos de resposta a situações de risco da comunidade. Os objetivos do estudo são avaliar o esforço empregue na comunicação do risco pela autarquia e captar a perceção dos munícipes, quer do risco, quer da receção das mensagens e participação ativa nas decisões para a capacitação de um município alerta, consciente e capaz de agir preventivamente.Não existindo consenso entre técnicos, decisores e o público leigo em matéria de perceção do risco, urge comungar a noção de risco, simetrizando conteúdos entre peritos e desconhecedores. A prática de uma comunicação integrada do risco, estrategicamente voltada para públicos em diferentes níveis de consciência/informação, constitui-se como um meio eficaz para a capacitação populacional quanto à compreensão, avaliação e ação sobre os riscos a que pode, infortunadamente, estar sujeita. Esta comunicação aproxima-se do ideal de governança do risco, caracterizado por uma comunicação bilateral, na qualidade de canal de troca de (in)formações e opiniões entre os stakeholders para que, no fim, convirjam na tomada de decisão face aos comportamentos a implementar.Acreditando na comunicação como pedra basilar, apta a instituir as condições do relacionamento organis- mos-público, registam-se parcas investigações na área da comunicação estratégica, nomeadamente em contexto local, daí o interesse pela Vila de Mafra.Recorre-se a uma metodologia mista, usando ferramentas de pesquisa qualitativas – como uma auditoria à comunicação da Câmara; análise SWOT; mapeamento de stakeholders; entrevistas a responsáveis pela tomada de decisão, governança e comunicação do risco – e quantitativas – com o inquérito a uma amostra da população mafrense.Em resultado queremos aferir as dúvidas da comunidade mafrense no que concerne à comunicação rececionada para a sua capacitação, assim como qual a abertura à sua opinião sobre a legitimidade das decisões tomadas em situação de risco. Esperamos auxiliar no (re)estabelecimento de uma comunicação estratégica fluida e mútua entre a Câmara Municipal e a comunidade envolvente, corroborando a grande responsabilidade que justifica a sua existência neste município.
    2020-10-12Conference object Restricted access Show more
  • Edge virtualization in multihomed vehicular networks
    Publication . Silva, Miguel; Luís, Miguel; Sargento, Susana
    Vehicular Networks (VANETs) are a critical component of a Smart City environment. They extended the connectivity plane with support for a wide range of applications, from safety to entertainment. Such services, when deployed outside the vehicular network, may imply an additional delay, which can be critical. In addition, these services become inaccessible whenever the vehicles lose contact with the infrastructure.This paper proposes a practical solution that aims to minimize the impact of the services' location and its inaccessibility in a VANET. The solution focuses on using Network Function Virtualization technologies to support the deployment of the services at the edge of a mobility-enabled multihomed VANET, thus allowing the services to be accessible in intermittent connectivity situations, as well as enabling lower delays for critical services. The results obtained show that the solution is capable of deploying services at the edge of the VANET with low delay and with a fast recovery when in handover and mobility scenarios.
    2020-10-12Conference object Open access Show more
  • The PR function in portuguese SME: betwixt suspicion and curiosity
    Publication . Eiró-Gomes, Mafalda; Raposo, Ana Luísa Canelas Rasquilho
    Between what has been called the dominant paradigm, Grunig’s symmetrical approach, and what we may, due to a lack of a better word call the critical paradigm, the last 40 years haven’t seem to be able to offer a coherent and identitary theoretical corpus for the discipline or even, a coherent theoretical terminology, globally recognized for the role performed by PR practitioners all over different kinds of organizations, enterprises or public institutions (Grunig, 1002; Heath, 2001; L’Etang, 2008; Hazelton, 2006). What are their main functions, what’s their role at the manager level in promoting better relationships between the organization and its stakeholders or in the promotion of a better corporate citizenship? What is the PR impact in society? None of these questions are new. We have been struggling with them since, at least, the late eighties of the last century but now practitioners are facing new challenges due to globalization of markets, migrations with new intercultural tournaments or the increase of information exchanges, which, as Wolton (2019) has defended, cannot be seen as sufficient to promote the human communication. Communication is understood in this article as the human capacity to share and to be able to negotiate, that is, to build authentic relationships. Against many approaches that tend to consider the concepts of Public Relations (PR) or Corporate Communication as mere instrumental contributes to the report function of so many organizations, authors consider communication as constitutive of the organizations and of all the human practices and tend to see, as well, the PR function as being pervasive to all the organization levels from the operational to the managerial and strategic one (Dozier, 1992; Steyn and Puth, 2000). This research paper offers a summary of an ongoing research focused on the understanding of the PR function in the portuguese small and medium size enterprises (SME). The research has as its main objectives to understand how SME perceive the PR function as well as to enable researchers to make sense of the state of the function in these enterprises. In the framework of a pragmatist approach to research it goes without saying that to figure out the problems and needs in what concerns PR in this sector, in order to be able to offer some theoretical insights that can be used by those organizations, is also a fundamental purpose of the work being developed. A manual is being written in accordance to the main expressed needs: from a better understanding of the discipline, to what has been called “B to B communication” as well as to be able to construct bridges with different kinds of stakeholders especially in the context of exportations where notions as those of trust and transparency are the main actors. Public affairs or questions concerning risk and crisis communication are some of the theoretical aspects that are also being explored. In the framework of a pragmatist worldview, a sequential explanatory mixed methods approach was developed. The sequential explanatory approach is one of the three kinds of mixed methods basic designs proposed by Creswell (Creswell, 2014; Creswell and Creswell, 2018) concomitantly with the convergent parallel and the exploratory sequential. In the case of the convergent parallel mixed method design the qualitative and the quantitative data are treated in parallel and compared in order to see if the findings confirm or refute each other, while in the exploratory one the quantitative data collection and analysis follows the qualitative phase aiming to a future possible generalization of the findings. In the case of the sequential explanatory the qualitative findings help to explain the quantitative results and offer an in-depth understanding of the situation under investigation. This is a two phase design that is characterized by an initial quantitative phase of data collection and analysis, followed by a phase of qualitative data collection and analysis. If it is true that the first results help frame the kind of qualitative questions that must be asked to participants it is important to note that one of the most relevant aspects of this kind of inquiry is that the qualitative findings help to confirm and explain the data found during the quantitative phase. Small and medium-sized enterprises are the engine of the portuguese economy, representing almost 99% of the corporate structure in Portugal. A quarter of the portuguese small and medium-sized enterprises are managed by women and the Portuguese Agency for Competitiveness and Innovation has created a network of enterprises that, beyond being leaders in their sectors, have a woman as a leader - Rede Mulher Lider (Leader Woman Network). No research has been done considering this group of enterprises and almost nothing is known about the role of PR in these enterprises. The general idea however is that these SME could gain if recognised outside their traditional zones of influence and that their CEOS are willing to expand their exportations. In this sense a study of the potentialities of a strategic approach to communication is felt as needed. For many of these enterprises a certain secrecy - the secret is the soul of the business as a portugeuse say states - and a mistrust concerning PR seem to be quite prevalent. In a first moment, through an online survey, researchers tried to get an overall picture of the organizations that could enable them to understand their structure and how their "communicative" aspects were dealt with. The quantitative data gathering was undertaken over 2 months - november and december 2019 and 25 out of the 76 enterprises that belong to the Network answered the survey (33%). The great majority of the organizations under analysis operates in the industry business (61,5%) or in the services business (30,8%), focusing on business-to-business (80,8%) activities. The business-to-business (B2B) is here understood as “relating to the sale of a product for any use other than personal consumption. The buyer may be a manufacturer, a reseller, a government body, a non-profit-making institution or any organisation other than an ultimate consumer” (Cornelissen 2004: 184). Taking into consideration the purpose of this study, it was essential to know if there is a communication department who performed the role of Public Relations in these specific organizations. Almost 70% of the organizations declare not having a communication/public relations department. Even though, when asked if in the absence of a specific structure to manage the PR function if there is someone who is concerned about these issues the majority of the respondents (73,7%) answered “yes”. When focusing on who has this responsibility, data points to marketing, commercial and sales functions as the most relevant ones. Thereby, as the researchers found a relevant number of organizations that didn't have a specific communication structure, secondly the focus was on evaluating if this function could be outsourced, totally or partially, as a complement to the work done in-house. Here the results showed that the organizations tend to not use outsourcing models in what concerns communication services (61,5%). Regarding the issues related to communication with the employees (Internal Communication), these activities seem to be managed in the majority of the organizations by the Human Resources Departments. In this area the investments can be summarized in team building initiatives, christmas lunches or dinners. In terms of channels of communication with different stakeholders, from employees, to media, clientes, suppliers the “email” appears as the most prefered option. When asked about the way of promotion followed, fairs (57,7%) and advertising to products (69,2%) are the most highlighted. The majority of the organizations declared to not having a Sustainability Report (96,2%), a Corporate Citizenship Policy (61,5%), a Spokesperson (61,5%) or a risk/crisis communication plan (76,9%). Even the Media Relations, which is appointed as the most well known area related to the PR function, is not a priority for the portuguese SME enterprises under study. 61,5% stated to not invest in relations with the traditional media and 88,5% don’t consider influencers, of any kind (from the old brand ambassadors to the new digital influencers), at all. In conclusion, the data collected during this first part of the research pointed to the unrecognition of the PR function among the organizations under analysis. The SME enterprises in Portugal aren´t able to grasp what are the main activities under the responsibility of the PR function or the benefits that can derive from the investments in this area. They state however that they could grow if they could reach different publics or be better recognised in international markets. The challenges posed by a more globalised market and what has been called the “social” media are highlighted as the main concerns for these organisations. At the moment, and as it has been already said, the researchers are finishing the second part of the inquiry and are trying to interview as many CEOs as possible in order to understand in a more accurate way how they see the role of the PR function in their organizations.
    2020-10-12Conference object Restricted access Show more