The complexities of coupled environmental and human systems across the space and time of fragile systems challenge new data-driven methodologies. Combining geographic information systems (GIS) and artificial neural networks (ANN) allows us to design a model that forecasts the erosion changes in Costa da Caparica, Lisbon, Portugal, for 2021, with a high accuracy level. The GIS–ANN model proves to be a powerful tool, as it analyzes and provides the “where” and the “why” dynamics that have happened or will happen in the future. According to the literature, ANNs present noteworthy advantages compared to the other methods that are used for prediction and decision making in urban coastal areas. In order to conduct a sensitivity analysis on natural and social forces, as well as dynamic relations in the dune–beach system of the study area, two types of ANNs were tested on a GIS environment: radial basis function (RBF) and multilayer perceptron (MLP). The GIS–ANN model helps to understand the factors that impact coastal erosion changes, and the importance of having an intelligent environmental decision support system to address these risks. This quantitative knowledge of the erosion changes and the analytical map-based frame are essential for an integrated management of the area and the establishment of pro-sustainability policies.
Este estudo trata da caracterização multitemporal de barras e ilhas fluviais no baixo curso do rio Jaguaribe, particularmente no segmento a jusante da barragem do açude Castanhão, em anos secos e chuvosos. Metodologicamente, recorreu-se à determinação de anos-padrão secos e chuvosos, à utilização das ferramentas de sensoriamento remoto, através do uso de fotografias aéreas, imagens de satélite e softwares de geoprocessamento, para o mapeamento das diferentes tipologias de barras e ilhas fluviais. Os resultados indicaram que, embora haja especificidades nos dados morfológicos de quantidade e área para as diferentes tipologias de barras fluviais e ilhas, em geral, a formação destas feições reflete as variações de vazão no baixo curso do rio Jaguaribe, como comprovam os dados do coeficiente de correlação linear de Pearson e do coeficiente de determinação. Ou seja, nos anos considerados secos, observou-se uma redução das feições devido à ausência de fluxos significativos para promover o transporte de sedimentos, ao passo que, em anos chuvosos, verificou-se um incremento de barras fluviais, sobretudo pela ação cíclica dos processos erosivos e sedimentares, que promoveram a distribuição e redistribuição dos sedimentos no canal. Em adição, verificou-se que a correlação é mais expressiva quando se considera a posição da barra no canal (lateral ou central), em detrimento da forma/geometria (pontal), cuja formação está diretamente associada a outros fatores geomorfológicos.
Coastal areas are among the most dynamic earth systems as they are exposed to powerful agents. Nearshore wave energy is one of the most important triggering factors for erosion and flooding and is often neglected for severe infrastructure damaging, property losses and loss of life. These consequences are amplified with high population density and heavy infrastructure implantation as it happens in Lisbon (Portugal). In this context, it is of great importance for coastal stakeholders, decision-makers and civil protection entities to estimate precisely the spatial distribution of storm hazard for prevention and mitigation purposes, as well as to design adjusted answers for calamity responses. We apply a coastal storm hazard index (CSHI) considering triggering and conditioning variables involved in the effects of an extreme storm, namely: 100-year return period of SWAN modelled H s , and its spatial distribution across the study area, land use, number of buildings, height, slope, geology, geomorphology, erosion/ accretion rates, width of the systems, exposure of the coastline, bathymetry and legally protected areas. The variables were weighted according to a hierarchical analysis process and classified into five classes of exposure. A validation process was then implemented by comparing the occurrences identified in the last two decades newspapers and the storm hazard classification, showing a satisfactory validation results. The results show a classified storm hazard map that identifies the most and the less exposed areas. High values of CSHI occur in areas with excessive human pressure, low heights sandy systems with significant costal erosion rates. The main type of consequences identified are associated with inland flooding and erosion, resulting in the destruction of coastal protection infrastructures, and population displacement leading to great economic and social impacts and loss of life.
Resumo -A determinação da taxa de erosão das plataformas rochosas litorais necessita de equipamento específico, adaptado às condições ambientais em que se desenvolvem estas plataformas. Neste trabalho, descreve-se a concepção de equipamento adaptado a esse fim -um microerosómetro do tipo TMEM (Traversing Micro-Erosion Meter) -ao qual foram introduzidas algumas modificações, que visam melhorar quantitativa e qualitativamente os dados a obter. São também indicados, para além das vantagens e limitações deste equipamento, os procedimentos principais seguidos nas fases de instalação e medição com o TMEM. Referem-se ainda os primeiros resultados obtidos num ensaio experimental levado a cabo numa plataforma calcária situada nos Tombadoiros, a norte da Ericeira, entre os níveis mínimo da preiamar morta e o nível máximo da preiamar viva. Os resultados correspondem a 96 dias de evolução entre duas observações no período de Outono/Inverno de 2000/2001 e apontam para uma taxa de rebaixamento médio da plataforma rochosa de 0,153mm/ano. A cobertura pelo líquene Verrucaria maura de mais de metade dos pontos de medição condicionou, no entanto, os resultados obtidos, tendo a separação destes em dois grupos permitido concluir que o sector de rocha limpa apresentou uma taxa de erosão 2,5 superior à do sector coberto por aquele líquene.Palavras-chave: plataforma rochosa litoral, microerosómetro, taxas de rebaixamento, Estremadura portuguesa
Purpose Universities are continually transforming its structure and governance in response to the new social, environmental and economic challenges. Particularly, there has recently been a growing academic interest for measuring sustainable practices of higher education institutions (HEI) aiming to monitor and reduce their carbon emissions, as well as transform them into more sustainable organizations. More recent studies began to focus also on the sustainable performance of distance education Universities. So it became crucial to evaluate their sustainability practices through sustainability assessment tools with the aim of improving their sustainability performance and boosting their role as agents of academic, social and economic change. The purpose of this study is to assess and compare holistically sustainability implementation in two similar distance learning universities and to evaluate their advantages and disadvantages. Design/methodology/approach One of the most rigorous and internationally used sustainability assessment tools was used – the Sustainability Tracking, Assessment and Rating System, to evaluate and compare sustainability implementation in two distance universities, one from Spain and another from Portugal: the Madrid Open University and Universidade Aberta. Indicators of both universities were compared and ways of improvement in both universities were widely discussed. Findings The results of this research show that there is a similar pattern in both universities. Both have low performance in campus operations and low levels of community participation but good performance in sustainability courses and programmes offer. The results of both institutions were compared and allowed a learning process for improvement. Originality/value This research hopes to contribute to the continuous research about the usefulness of sustainability assessment tools in particular when applied to distance universities at the time that offers new paths to carry out improved sustainable practices in crucial areas of interest such as research, administration, education and resource-saving. This research also highlights the value of distance learning universities and their ability to be more sustainable after the advent of COVID-19.
A navegação consulta e descarregamento dos títulos inseridos nas Bibliotecas Digitais UC Digitalis, UC Pombalina e UC Impactum, pressupõem a aceitação plena e sem reservas dos Termos e Condições de Uso destas Bibliotecas Digitais, disponíveis em https://digitalis.uc.pt/pt-pt/termos. Conforme exposto nos referidos Termos e Condições de Uso, o descarregamento de títulos de acesso restrito requer uma licença válida de autorização devendo o utilizador aceder ao(s) documento(s) a partir de um endereço de IP da instituição detentora da supramencionada licença. Ao utilizador é apenas permitido o descarregamento para uso pessoal, pelo que o emprego do(s) título(s) descarregado(s) para outro fim, designadamente comercial, carece de autorização do respetivo autor ou editor da obra. Na medida em que todas as obras da UC Digitalis se encontram protegidas pelo Código do Direito de Autor e Direitos Conexos e demais legislação aplicável, toda a cópia, parcial ou total, deste documento, nos casos em que é legalmente admitida, deverá conter ou fazer-se acompanhar por este aviso.
The study of peri-urbanization attracted attention in the final quarter of the 20th century, due to the pace it acquired worldwide and the implication that urbanization and overall settlement patterns have on social sustainability and development. Theoretical and conceptual achievements are remarkable. Multi-country collaboration has produced a growing body of research on sustainability and peri-urban settlements. There is a lack, however, of a review of the practices of peri-urban informal settlements, the predominant mode of urban expansion, mainly in developing and rapidly urbanizing regions of the world. The purpose is, then, to systematize, from recent literature, the knowledge of the context, challenges, and practices, as well as their impacts and potential courses of action, to ensure sustainability in human–natural complex of the territory beyond urban cores, suburbs, or slums. A systematic review approach was adopted, for articles published in reputable journals, with support of previous reviews, books, and reports. A pragmatist combination of content analysis and critical review identified core topics and highlighted contrasting views. An analytical framework is proposed. Four categories—drivers, challenges and practices, impact, and future trends—are proposed as an adequate approach to systematizing the literature. The review finds that the practices focus on service and resource provision, on regulations to approximate informal to formal institutions, and on an economy founded on the resource base and service provision. This review provides insights on future trends and research topics.
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