Nowadays, passengers in urban public transport systems do not only seek a shorttime travel, but they also ask for optimizing other criteria such as cost and effort. Therefore, an efficient routing system should incsorporate a multiobjective analysis into its search process. Several algorithms have been proposed to optimally compute the set of nondominated journeys while going from one place to another such as the generalisation of the algorithm of Dijkstra. However, such approaches become less performant or even inapplicable when the size of the network becomes very large or when the number of criteria considered is very important. Therefore, we propose in this paper an advanced heuristic approach whereby a Genetic Algorithm (GA) is combined with a Variable Neighbourhood Search (VNS) to solve the Multicriteria Shortest Path Problem (MSPP) in multimodal networks. As transportation modes, we focus on railway, bus, tram and pedestrian. As optimization criteria, we consider travel time, monetary cost, number of transfers and the total walking time. The proposed approach is compared with the exact algorithm of Dijkstra, as well as, with a standard GA and a pure VNS. Experimental results have been assessed by solving real life itinerary problems defined on the transport network of the city of Paris and its suburbs. Results indicate that the proposed combination GA-VNS represents the best approach in terms of computational time and solutions quality for a real world routing system.
Due to the exponential rise of the Internet in the last two decades, the digital presence has seen an enormous increase. Today, billions of people, devices and objects are digitally connected making the interactions much easier than before. To securely establish this connectivity in the digital era, proving digital identities has become crucial. Due to this, a growing number of organizations are building solutions that establish, verify and manage digital identities. Yet, a solution whereby digital identities and their associated data are efficiently managed is still far from being achieved. To fully understand the reason behind this lack, this paper provides a detailed state of the art related to identity management systems. It overviews traditional systems, analyses their strengths and limitations. This work highly focuses on the novel decentralized identity systems based on blockchain; a complete study describing their architecture, components, lifecycle and workflow is detailed. Additionally, solutions enabling decentralized identity are discussed, analysed and compared according to the ten principles of self-sovereign identity. Lastly, the challenges hindering the shift toward the fully decentralized identity paradigm are discussed.
RESUMOA catarata congênita é uma causa importante de deficiência visual, principalmente por ambliopia, com prevalência aproximada de 0,4%. Seu manejo cirúrgico, inclusive em crianças, tem se desenvolvido, levando a melhores resultados visuais e contribuindo para o controle da ambliopia. Objetivo: Relatar os resultados precoces de uma série de casos submetidos a diferentes modalidades cirúrgicas para catarata congênita no Serviço de Catarata do Instituto de Oftalmologia Tadeu Cvintal (IOTC) de janeiro de 2004 a janeiro de 2005.métodos: Estudo retrospectivo em 19 crianças (32 olhos) com catarata congênita. A série de casos foi dividida em três grupos de acordo com a abordagem cirúrgica: lensectomia via pars plana, facoaspiração com e sem implante de lente intraocular. A acuidade visual corrigida final foi registrada com quatro meses de pós-operatório. Resultados: Oito olhos foram submetidos à lensectomia, treze (13) à facoaspiração com implante de lente intra-ocular, e onze (11) à facoaspiração sem implante de lente intra-ocular. Em dez olhos foi realizada capsulotomia posterior primária. A única complicação observada foi opacidade de cápsula posterior em 60% (n=05) dos casos. Aproximadamente 43% dos pacientes (n=14) desenvolveram AV final corrigida entre 20/20 (LogMAR + 0.0) e 20/40 (LogMAR +0.3). Destes, oito (57%) eram olhos de crianças operadas de ambos os olhos (catarata bilateral). A média de idade em que foram operadas, neste grupo de melhor acuidade, foi de sete anos. Sete (50%) olhos foram submetidos a facoaspiração com implante de lente intra-ocular, e cinco (35%) destes foram submetidos á capsulotomia posterior secundária. Conclusão: A série de casos analisada apresentou bons resultados cirúrgicos e funcionais precoces, embora trata-se de um número pequeno e heterogêneo de pacientes. O acompanhamento a longo prazo desses pacientes é essencial para avaliarmos que papel as diferentes indicações cirúrgicas têm para o prognóstico visual funcional.Descritores: Catarata/congênito; Extração de catarata; Ambliopia; Criança
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