Sensibilidade visual ao contraste

O potencial que a medição da sensibilidade ao contraste representa como indicador de alterações do sistema visual não deve ser esquecido. Neste artigo é feita uma abordagem dos seus princípios e aplicações. Pretende-se assim despertar a atenção para as vantagens do uso da sensibilidade ao contraste como complemento a outros testes, nomeadamente, a acuidade visual de Snellen. Este artigo está dividido em três partes: primeira parte - revisão dos fundamentos da técnica; segunda parte - potenciais aplicações; terceira - aspectos a ter em conta na interpretação dos resultado

The use of smartphones and ereaders as low vision aids

Summary In this debate I want to talk about consumers’ technology and the role they can have for optometrists working in vision rehabilitation. To do this I am sharing some questions that I think we should talk about

Recolha e análise de dados de contactos físicos e sociais numa rede tolerante a atrasos

As redes tolerantes a atrasos surgiram com o propósito de abordar o problema de comunicação em redes onde a ligação é intermitente e feita através de contactos oportunistas. Um caso particular destas redes são aquelas em que os nós são dispositivos transportados por pessoas, as Pocket Switch Networks. A relação social entre os nós tem sido recentemente explorada na decisão de encaminhamento neste tipo de redes.Neste trabalho, foi concebido um sistema de recolha de dados dos contactos físicos e sociais numa RTA com o objetivo de avaliar uma nova métrica social a ser usada na decisão de encaminhamento

Determinação de parâmetros críticos de impressão da informação escrita para crianças com baixa visão

CursoA impressão ampliada é a forma mais prática e barata de disponibilizar informação a pessoas com baixa visão. Quando devidamente escalada este tipo de informação é também, provavelmente, a forma mais eficiente de disponibilizar a informação ao aluno com baixa visão PARTE 1 (teórica) Conceitos fundamentais do fenómeno visual: dimensões da visão, do olho ao cérebro visão normal, acuidade visual. Serão tocadas a temáticas da avaliação da visão, conceito de unidade M, importância do contraste e do “crowding”. [Luísa Santana Silva] O teste MNread e a sua concepção [António Filipe Macedo] PARTE 2 (prática) Serão exemplificados os testes desenhados por Lea Hyvarinen e por Gordon Legge. RESULTADOS ESPERADOS No final deste curso os participantes devem ser capazes de: entender os princípios dos testes utilizados, possuam capacidade para utilizar os testes e sejam capazes de extrair informação útil para cada caso de baixa visão. AVALIAÇÃO Trabalho de grupo, em cada grupo de 4 pessoas

A countermeasure approach for brute-force timing attacks on cache privacy in named data networking architectures

One key feature of named data networks (NDN) is supporting in-network caching to increase the content distribution for today’s Internet needs. However, previously cached contents may be threatened by side-channel timing measurements/attacks. For example, one adversary can identify previously cached contents by distinguishing between uncached and cached contents from the in-network caching node, namely the edge NDN router. The attacks can be mitigated by the previously proposed methods effectively. However, these countermeasures may be against the NDN paradigm, affecting the content distribution performance. This work studied the side-channel timing attack on streaming over NDN applications and proposed a capable approach to mitigate it. Firstly, a recent side-channel timing attack, designated by brute-force, was implemented on ndnSIM using the AT&T network topology. Then, a multi-level countermeasure method, designated by detection and defense (DaD), is proposed to mitigate this attack. Simulation results showed that DaD distinguishes between legitimate and adversary nodes. During the attack, the proposed DaD multi-level approach achieved the minimum cache hit ratio (≈0.7%) compared to traditional countermeasures (≈4.1% in probabilistic and ≈3.7% in freshness) without compromising legitimate requests.This work has been supported by FCT - Fundação para a Ciência e Tecnologia within the R&D Units Project Scope: UIDB/00319/2020

Elements of a methodology to assess the alignment of core-values in collaborative networks

Collaborative networks are typically formed by heterogeneous and autonomous entities, and thus it is natural that each member has its own set of core-values. Since these values somehow drive the behaviour of the involved entities, the ability to quickly identify partners with compatible or common core-values represents an important element for the success of collaborative networks. However, tools to assess or measure the level of alignment of core-values are lacking. Since the concept of 'alignment' in this context is still ill-defined and shows a multifaceted nature, three perspectives are discussed. The first one uses a causal maps approach in order to capture, structure, and represent the influence relationships among core-values. This representation provides the basis to measure the alignment in terms of the structural similarity and influence among value systems. The second perspective considers the compatibility and incompatibility among core-values in order to define the alignment level. Under this perspective we propose a fuzzy inference system to estimate the alignment level, since this approach allows dealing with variables that are vaguely defined, and whose inter-relationships are difficult to define. Another advantage provided by this method is the possibility to incorporate expert human judgment in the definition of the alignment level. The last perspective uses a belief Bayesian network method, and was selected in order to assess the alignment level based on members' past behaviour. An example of application is presented where the details of each method are discussed

A method to analyse the alignment of core values in collaborative networked organisations

Since collaborative networked organisations are usually formed by independent and heterogeneous entities, it is natural that each member holds his own set of values, and that conflicts among partners might emerge because of some misalignment of values. In contrast, it is often stated in literature that the alignment between the value systems of members involved in collaborative processes is a prerequisite for successful co-working. As a result, the issue of core value alignment in collaborative networks started to attract attention. However, methods to analyse such alignment are lacking mainly because the concept of 'alignment' in this context is still ill defined and shows a multifaceted nature. As a contribution to the area, this article introduces an approach based on causal models and graph theory for the analysis of core value alignment in collaborative networks. The potential application of the approach is then discussed in the virtual organisations' breeding environment context

Mota-Engil: a solution to turnover its negative stock market performance

A Work Project, presented as part of the requirements for the Award of a Masters Degree in Finance from the NOVA – School of Business and EconomicsThis project started as an M&A Field Lab, where students are challenged to advise the selected company (Mota-Engil) on typical M&A proposal from an investment bank perspective. However, during the Field Lab path, the source of information to university students proved to be limited, specially in what concerns the searching for an operation abroad. Nevertheless, along the way, I tried to understand the reason why Mota-Engil’s shares were being so bearish in the stock market. So, this project reflects the investigation I did to justify the market valuation of Mota-Engil, to which I proposed opposite solutions to turnaround the negative performance. All the analysis refers to the year end of 2010 and it is important to state that companies’ valuations were done as the base to understand possible changes on corporate value