Travel Agencies: From online channel conflict to multi-channel harmony

The adoption of Internet as a distribution channel and a privileged e-commerce tool has pressed Travel Agencies (TAs) to a latent channel conflict. Our main interest is to understand how the traditional independent travel agencies in Portugal deal with the online channel. We suggest that TAs have to develop an innovative business model based on the online and offline complementary channels, in order to achieve a multi-channel harmony

Recognizing pro-R closures of regular languages

Given a regular language L, we effectively construct a unary semigroup that recognizes the topological closure of L in the free unary semigroup relative to the variety of unary semigroups generated by the pseudovariety R of all finite R-trivial semigroups. In particular, we obtain a new effective solution of the separation problem of regular languages by R-languages

How would tourists use Green Spaces? Case Studies in Lisbon

EntretextosThis report provides in a relative condensed format the results of small-scale study undertaken in Lisbon during the Meeting of the CyberParks Project (www.cost.eu/COST_Actions/tud/Actions/TU1306). CyberParks is a COST Action coordinated by the Universidade Lusófona at the CeiED - Interdisciplinary Research Centre for Education and Development. The Project aims at creating a research platform on the relationship between Information and Communication Technologies (ICT) and the production of public open spaces, and their relevance to sustainable urban development. The impacts of this relationship are being explored from social, ecological, urban design and technological perspectives. Based on the supposition that the participants of the Meeting are tourists visiting Lisbon, a survey was carried out on the topic how people actually use and how they would use public spaces. This survey is also the first approach to the case study areas chosen in Lisbon: Parque Quinta das Conchas and Jardim da Estrela. Both green spaces will be subject of further studies in the forthcoming years. This study employed (1) a questionnaire for measuring the user’s experience and preferences, and (2) two different tracking devices that utilise GNSS (Global Navigation Satellite Systems), in our case the GPS for satellite positioning technologies. It also presents the results of a study on the relevance of wi-fi in Lisbon’s public spaces. Even considering that the surveys in Lisbon’s green spaces are a first exercise within the work programme of CyberParks they show important outcomes. On the one hand, regarding the technologies used and their potential for research and on the other hand the findings about Lisbon’s green spaces. It should be noted that the conducted surveys and the gathered data are statistically not representative, but can be characterised as an empirical case and as a showcase, as how tourists tend to use a green space. The results shows that surveys benefit from multiple research methods and from combining insights.Este relatório apresenta, em formato condensado, os resultados de um estudo de pequena escala realizado em Lisboa durante o Seminário do Projeto CyberParks. CyberParks é uma Ação COST coordenada pela Universidade Lusófona/CeiED - Centro de Estudos Interdisciplinares em Educação e Desenvolvimento. O projeto visa a criação de uma plataforma de debate sobre a relação entre as Tecnologias de Informação e Comunicação (TIC) e a produção de espaços públicos, e da sua relevância para o desenvolvimento urbano sustentável. Os impactos dessa relação estão a ser explorados a partir de perspetivas sociais, ecológicas, tecnológicas e de desenho urbano. Na sua etapa exploratória, este estudo assenta na suposição de que os participantes do Seminário são turistas de visita a Lisboa. A partir dos dados recolhidos pelos investigadores envolvidos na ação COST, foi realizada uma análise à forma como diferentes indivíduos usam, e como poderão usar, diferentes espaços públicos verdes. Este estudo apresenta, portanto, a primeira abordagem às áreas de estudos selecionadas em Lisboa. São elas o Parque Quinta das Conchas e o Jardim da Estrela. Ambos os espaços verdes serão objeto de novos estudos nos próximos anos. Neste primeiro estudo exploratório foram empregues: (1) um questionário, para aferir a experiência de um potencial utilizador e as suas preferências, e (2) dois dispositivos diferentes de rastreamento que utilizam tecnologia GNSS (Sistemas de Navegação Global por Satélite) e, no nosso caso, o GPS para as tecnologias de posicionamento por satélite. Ele também apresenta os resultados de um estudo realizado sobre a relevância do wi-fi em espaços públicos na cidade de Lisboa. Mesmo considerando que os estudos realizados nos espaços verdes representam um primeiro exercício no âmbito do programa de trabalho do CyberParks em Lisboa, são aqui revelados resultados importantes. Por um lado, o recurso às tecnologias utilizadas e seu potencial para a investigação e, por outro lado, os resultados sobre a vivência dos espaços verdes. Deve-se notar que os dados recolhidos não são estatisticamente representativos, mas evidenciam um caso empírico de como turistas tendem a usar um espaço verde urbano. A combinação do questionário com novos métodos digitais resultou num grande ganho de conhecimento, recobrindo as áreas de estudo sob a perspetiva de um turista, para além de maiores informações sobre as potencialidades e limites da tecnologia digital como ferramenta de investigação. Os resultados mostram que a investigação no campo social pode se beneficiar da combinação de vários métodos e técnicas

Adaptive, locally-linear models of complex dynamics

The dynamics of complex systems generally include high-dimensional, non-stationary and non-linear behavior, all of which pose fundamental challenges to quantitative understanding. To address these difficulties we detail a new approach based on local linear models within windows determined adaptively from the data. While the dynamics within each window are simple, consisting of exponential decay, growth and oscillations, the collection of local parameters across all windows provides a principled characterization of the full time series. To explore the resulting model space, we develop a novel likelihood-based hierarchical clustering and we examine the eigenvalues of the linear dynamics. We demonstrate our analysis with the Lorenz system undergoing stable spiral dynamics and in the standard chaotic regime. Applied to the posture dynamics of the nematode $C. elegans$ our approach identifies fine-grained behavioral states and model dynamics which fluctuate close to an instability boundary, and we detail a bifurcation in a transition from forward to backward crawling. Finally, we analyze whole-brain imaging in $C. elegans$ and show that the stability of global brain states changes with oxygen concentration.Comment: 25 pages, 16 figure

Stability of a two-sublattice spin-glass model

We study the stability of the replica-symmetric solution of a two-sublattice infinite-range spin-glass model, which can describe the transition from antiferromagnetic to spin glass state. The eigenvalues associated with replica-symmetric perturbations are in general complex. The natural generalization of the usual stability condition is to require the real part of these eigenvalues to be positive. The necessary and sufficient conditions for all the roots of the secular equation to have positive real parts is given by the Hurwitz criterion. The generalized stability condition allows a consistent analysis of the phase diagram within the replica-symmetric approximation.Comment: 21 pages, 5 figure