Search

Quantum secret sharing (QSS) allows a dealer to distribute a secret quantum state among a set of parties in such a way that certain authorized subsets can reconstruct the secret, while unauthorized subsets obtain no information about it. Previous works on QSS for general access structures focused solely on the existence of perfectly secure schemes, and the share size of the known schemes is necessarily exponential even in cases where the access structure is computed by polynomial size monotone circuits. This stands in stark contrast to the classical setting, where polynomial-time computationally-secure secret sharing schemes have been long known for all access structures computed by polynomial-size monotone circuits under standard hardness assumptions, and one can even obtain shares which are much shorter than the secret (which is impossible with perfect security). While QSS was introduced over twenty years ago, previous works only considered information-theoretic privacy. In this work, we initiate the study of computationally-secure QSS and show that computational assumptions help significantly in building QSS schemes, just as in the classical case. We present a simple compiler and use it to obtain a large variety results: We construct polynomial-time computationally-secure QSS schemes under standard hardness assumptions for a rich class of access structures. This includes many access structures for which previous results in QSS necessarily required exponential share size. In fact, we can go even further: We construct QSS schemes for which the size of the quantum shares is significantly smaller than the size of the secret. As in the classical setting, this is impossible with perfect security. We also apply our compiler to obtain results beyond computational QSS. In the information-theoretic setting, we improve the share size of perfect QSS schemes for a large class of n-party access structures to 1.5^{n+o(n)}, improving upon best known schemes and matching the best

Artificially intelligent perception is increasingly present in the lives of every one of us. Vehicles are no exception, (...) In the near future, pattern recognition will have an even stronger role in vehicles, as self-driving cars will require automated ways to understand what is happening around (and within) them and act accordingly. (...) This doctoral work focused on advancing in-vehicle sensing through the research of novel computer vision and pattern recognition methodologies for both biometrics and wellbeing monitoring. The main focus has been on electrocardiogram (ECG) biometrics, a trait well-known for its potential for seamless driver monitoring. Major efforts were devoted to achieving improved performance in identification and identity verification in off-the-person scenarios, well-known for increased noise and variability. Here, end-to-end deep learning ECG biometric solutions were proposed and important topics were addressed such as cross-database and long-term performance, waveform relevance through explainability, and interlead conversion. Face biometrics, a natural complement to the ECG in seamless unconstrained scenarios, was also studied in this work. The open challenges of masked face recognition and interpretability in biometrics were tackled in an effort to evolve towards algorithms that are more transparent, trustworthy, and robust to significant occlusions. Within the topic of wellbeing monitoring, improved solutions to multimodal emotion recognition in groups of people and activity/violence recognition in in-vehicle scenarios were proposed. At last, we also proposed a novel way to learn template security within end-to-end models, dismissing additional separate encryption processes, and a self-supervised learning approach tailored to sequential data, in order to ensure data security and optimal performance. (...), Comment: Doctoral thesis presented and approved on the 21st of December 2022 to the University of Porto

Multi-party quantum computation (MPQC) allows a set of parties to securely compute a quantum circuit over private quantum data. Current MPQC protocols rely on the fact that the network is synchronous, i.e., messages sent are guaranteed to be delivered within a known fixed delay upper bound, and unfortunately completely break down even when only a single message arrives late. Motivated by real-world networks, the seminal work of Ben-Or, Canetti and Goldreich (STOC'93) initiated the study of multi-party computation for classical circuits over asynchronous networks, where the network delay can be arbitrary. In this work, we begin the study of asynchronous multi-party quantum computation (AMPQC) protocols, where the circuit to compute is quantum. Our results completely characterize the optimal achievable corruption threshold: we present an n-party AMPQC protocol secure up to t < n/4 corruptions, and an impossibility result when t ≥ n/4 parties are corrupted. Remarkably, this characterization differs from the analogous classical setting, where the optimal corruption threshold is t < n/3.

As two sides of the same coin, causality and explainable artificial intelligence (xAI) were initially proposed and developed with different goals. However, the latter can only be complete when seen through the lens of the causality framework. As such, we propose a novel causality-inspired framework for xAI that creates an environment for the development of xAI approaches. To show its applicability, biometrics was used as case study. For this, we have analysed 81 research papers on a myriad of biometric modalities and different tasks. We have categorised each of these methods according to our novel xAI Ladder and discussed the future directions of the field.

We consider the problem of designing low-redundancy codes in settings where one must correct deletions in conjunction with substitutions or adjacent transpositions; a combination of errors that is usually observed in DNA-based data storage. One of the most basic versions of this problem was settled more than 50 years ago by Levenshtein, who proved that binary Varshamov-Tenengolts codes correct one arbitrary edit error, i.e., one deletion or one substitution, with nearly optimal redundancy. However, this approach fails to extend to many simple and natural variations of the binary single-edit error setting. In this work, we make progress on the code design problem above in three such variations: - We construct linear-time encodable and decodable length-n non-binary codes correcting a single edit error with nearly optimal redundancy log n+O(log log n), providing an alternative simpler proof of a result by Cai, Chee, Gabrys, Kiah, and Nguyen (IEEE Trans. Inf. Theory 2021). This is achieved by employing what we call weighted VT sketches, a new notion that may be of independent interest. - We show the existence of a binary code correcting one deletion or one adjacent transposition with nearly optimal redundancy log n+O(log log n). - We construct linear-time encodable and list-decodable binary codes with list-size 2 for one deletion and one substitution with redundancy 4log n+O(log log n). This matches the existential bound up to an O(log log n) additive term.

SARS-CoV-2 has presented direct and indirect challenges to the scientific community. One of the most prominent indirect challenges advents from the mandatory use of face masks in a large number of countries. Face recognition methods struggle to perform identity verification with similar accuracy on masked and unmasked individuals. It has been shown that the performance of these methods drops considerably in the presence of face masks, especially if the reference image is unmasked. We propose FocusFace, a multi-task architecture that uses contrastive learning to be able to accurately perform masked face recognition. The proposed architecture is designed to be trained from scratch or to work on top of state-of-the-art face recognition methods without sacrificing the capabilities of a existing models in conventional face recognition tasks. We also explore different approaches to design the contrastive learning module. Results are presented in terms of masked-masked (M-M) and unmasked-masked (U-M) face verification performance. For both settings, the results are on par with published methods, but for M-M specifically, the proposed method was able to outperform all the solutions that it was compared to. We further show that when using our method on top of already existing methods the training computational costs decrease significantly while retaining similar performances. The implementation and the trained models are available at GitHub., Comment: Accepted at the 16th IEEE International Conference on Automatic Face and Gesture Recognition, FG 2021

The recent Covid-19 pandemic and the fact that wearing masks in public is now mandatory in several countries, created challenges in the use of face recognition systems (FRS). In this work, we address the challenge of masked face recognition (MFR) and focus on evaluating the verification performance in FRS when verifying masked vs unmasked faces compared to verifying only unmasked faces. We propose a methodology that combines the traditional triplet loss and the mean squared error (MSE) intending to improve the robustness of an MFR system in the masked-unmasked comparison mode. The results obtained by our proposed method show improvements in a detailed step-wise ablation study. The conducted study showed significant performance gains induced by our proposed training paradigm and modified triplet loss on two evaluation databases., Comment: Accepted at 20th International Conference of the Biometrics Special Interest Group (BIOSIG 2021)

A imagem corporal é um tema que vem se ampliando nos últimos anos. Por isso, a partir de uma revisão integrativa da literatura efetuada na plataforma Scientific Eletronic Library Online, realizou-se uma pesquisa em 26 artigos publicados no ano de 2016, com o objetivo de identificar as principais características dos textos sobre imagem corporal. Os resultados apontam para três tipos de estudo predominantes: a) artigos de revisão; b) validação de instrumentos e protocolos e; c) análise dos níveis de satisfação/insatisfação com a imagem corporal de grupos distintos. A partir dessas informações, também foi possível concluir que são necessários novos estudos, sobretudo, vinculados às possíveis determinações sociais sobre a imagem corporal., Body image is a theme that has been expanding in recent years. Therefore, based on an integrative literature review carried out on the Scientific Electronic Electronic Library Online (SciELO) platform, a survey was carried out on 26 articles published in 2016, to identify the main characteristics of texts on body image. The results point to three predominant types of study, being them, a) review articles; b) validation of instruments and protocols and; c) analysis of the levels of satisfaction/dissatisfaction with the body image of different groups. From this information, it was also possible to conclude that further studies are needed, above all, linked to possible social determinations about body image.

A imagem corporal é um tema que vem se ampliando nos últimos anos. Por isso, a partir de uma revisão integrativa da literatura efetuada na plataforma Scientific Eletronic Library Online, realizou-se uma pesquisa em 26 artigos publicados no ano de 2016, com o objetivo de identificar as principais características dos textos sobre imagem corporal. Os resultados apontam para três tipos de estudo predominantes: a) artigos de revisão; b) validação de instrumentos e protocolos e; c) análise dos níveis de satisfação/insatisfação com a imagem corporal de grupos distintos. A partir dessas informações, também foi possível concluir que são necessários novos estudos, sobretudo, vinculados às possíveis determinações sociais sobre a imagem corporal., Body image is a theme that has been expanding in recent years. Therefore, based on an integrative literature review carried out on the Scientific Electronic Electronic Library Online (SciELO) platform, a survey was carried out on 26 articles published in 2016, to identify the main characteristics of texts on body image. The results point to three predominant types of study, being them, a) review articles; b) validation of instruments and protocols and; c) analysis of the levels of satisfaction/dissatisfaction with the body image of different groups. From this information, it was also possible to conclude that further studies are needed, above all, linked to possible social determinations about body image.

A imagem corporal é um tema que vem se ampliando nos últimos anos. Por isso, a partir de uma revisão integrativa da literatura efetuada na plataforma Scientific Eletronic Library Online, realizou-se uma pesquisa em 26 artigos publicados no ano de 2016, com o objetivo de identificar as principais características dos textos sobre imagem corporal. Os resultados apontam para três tipos de estudo predominantes: a) artigos de revisão; b) validação de instrumentos e protocolos e; c) análise dos níveis de satisfação/insatisfação com a imagem corporal de grupos distintos. A partir dessas informações, também foi possível concluir que são necessários novos estudos, sobretudo, vinculados às possíveis determinações sociais sobre a imagem corporal., Body image is a theme that has been expanding in recent years. Therefore, based on an integrative literature review carried out on the Scientific Electronic Electronic Library Online (SciELO) platform, a survey was carried out on 26 articles published in 2016, to identify the main characteristics of texts on body image. The results point to three predominant types of study, being them, a) review articles; b) validation of instruments and protocols and; c) analysis of the levels of satisfaction/dissatisfaction with the body image of different groups. From this information, it was also possible to conclude that further studies are needed, above all, linked to possible social determinations about body image.

Body image is a theme that has been expanding in recent years. Therefore, based on an integrative literature review carried out on the Scientific Electronic Electronic Library Online (SciELO) platform, a survey was carried out on 26 articles published in 2016, to identify the main characteristics of texts on body image. The results point to three predominant types of study, being them, a) review articles; b) validation of instruments and protocols and; c) analysis of the levels of satisfaction/dissatisfaction with the body image of different groups. From this information, it was also possible to conclude that further studies are needed, above all, linked to possible social determinations about body image., A imagem corporal é um tema que vem se ampliando nos últimos anos. Por isso, a partir de uma revisão integrativa da literatura efetuada na plataforma Scientific Eletronic Library Online, realizou-se uma pesquisa em 26 artigos publicados no ano de 2016, com o objetivo de identificar as principais características dos textos sobre imagem corporal. Os resultados apontam para três tipos de estudo predominantes: a) artigos de revisão; b) validação de instrumentos e protocolos e; c) análise dos níveis de satisfação/insatisfação com a imagem corporal de grupos distintos. A partir dessas informações, também foi possível concluir que são necessários novos estudos, sobretudo, vinculados às possíveis determinações sociais sobre a imagem corporal.

Body image is a theme that has been expanding in recent years. Therefore, based on an integrative literature review carried out on the Scientific Electronic Electronic Library Online (SciELO) platform, a survey was carried out on 26 articles published in 2016, to identify the main characteristics of texts on body image. The results point to three predominant types of study, being them, a) review articles; b) validation of instruments and protocols and; c) analysis of the levels of satisfaction/dissatisfaction with the body image of different groups. From this information, it was also possible to conclude that further studies are needed, above all, linked to possible social determinations about body image., A imagem corporal é um tema que vem se ampliando nos últimos anos. Por isso, a partir de uma revisão integrativa da literatura efetuada na plataforma Scientific Eletronic Library Online, realizou-se uma pesquisa em 26 artigos publicados no ano de 2016, com o objetivo de identificar as principais características dos textos sobre imagem corporal. Os resultados apontam para três tipos de estudo predominantes: a) artigos de revisão; b) validação de instrumentos e protocolos e; c) análise dos níveis de satisfação/insatisfação com a imagem corporal de grupos distintos. A partir dessas informações, também foi possível concluir que são necessários novos estudos, sobretudo, vinculados às possíveis determinações sociais sobre a imagem corporal.

Body image is a theme that has been expanding in recent years. Therefore, based on an integrative literature review carried out on the Scientific Electronic Electronic Library Online (SciELO) platform, a survey was carried out on 26 articles published in 2016, to identify the main characteristics of texts on body image. The results point to three predominant types of study, being them, a) review articles; b) validation of instruments and protocols and; c) analysis of the levels of satisfaction/dissatisfaction with the body image of different groups. From this information, it was also possible to conclude that further studies are needed, above all, linked to possible social determinations about body image., A imagem corporal é um tema que vem se ampliando nos últimos anos. Por isso, a partir de uma revisão integrativa da literatura efetuada na plataforma Scientific Eletronic Library Online, realizou-se uma pesquisa em 26 artigos publicados no ano de 2016, com o objetivo de identificar as principais características dos textos sobre imagem corporal. Os resultados apontam para três tipos de estudo predominantes: a) artigos de revisão; b) validação de instrumentos e protocolos e; c) análise dos níveis de satisfação/insatisfação com a imagem corporal de grupos distintos. A partir dessas informações, também foi possível concluir que são necessários novos estudos, sobretudo, vinculados às possíveis determinações sociais sobre a imagem corporal.

We revisit the fundamental problem of determining seed length lower bounds for strong extractors and natural variants thereof. These variants stem from a "change in quantifiers" over the seeds of the extractor: While a strong extractor requires that the average output bias (over all seeds) is small for all input sources with sufficient min-entropy, a somewhere extractor only requires that there exists a seed whose output bias is small. More generally, we study what we call probable extractors, which on input a source with sufficient min-entropy guarantee that a large enough fraction of seeds have small enough associated output bias. Such extractors have played a key role in many constructions of pseudorandom objects, though they are often defined implicitly and have not been studied extensively. Prior known techniques fail to yield good seed length lower bounds when applied to the variants above. Our novel approach yields significantly improved lower bounds for somewhere and probable extractors. To complement this, we construct a somewhere extractor that implies our lower bound for such functions is tight in the high min-entropy regime. Surprisingly, this means that a random function is far from an optimal somewhere extractor in this regime. The techniques that we develop also yield an alternative, simpler proof of the celebrated optimal lower bound for strong extractors originally due to Radhakrishnan and Ta-Shma (SIAM J. Discrete Math., 2000).

As relações de gênero estão presentes em diferentes espaços sociais e muitas vezes expressam posturas preconceituosas. Este texto pretende analisar a relação presente entre o gênero feminino e a cultura em um evento esportivo e cultural na cidade de Goiânia a partir de um regulamento sexista amplamente divulgado nas mídias regionais. Método: Foi feita uma análise documental com o “ranking” disponibilizado por mídias sociais e, nele foram analisados dezenove itens discriminados nos critérios de interesse relacional heterossexual durante os jogos realizados no evento de uma universidade pública do estado de Goiás, interior do Brasil. Resultados: Os dados demonstram um movimento na qual a relação de subalternidade de alguns grupos foi evidenciado, a virilidade masculina protagonizou o evento, de forma que se estabeleceram relações desiguais entre homens e mulheres, na qual os corpos femininos foram colocados sob extrema avaliação e constrangimento. Conclusão: A conclusão aponta para uma série de preconceitos quanto aos comportamentos sexistas, misóginos, heteronormativos e étnico-raciais.

Atualmente o Equador tem sido foco da comunidade internacional, devido às transformações políticas às quais enfrenta o país e suas grandes reservas petrolíferas. Nesse sentido a presente análise buscará delinear os impactos internacionais e regionais implicados pelo atual cenários político equatoriano.

O modelo de corpo que é socialmente compreendido como belo e saudável apresenta as características que são necessárias ao modo de produção em vigor. Este, por sua vez, utiliza uma série de estratégias para a disseminação do padrão considerado ideal, sendo o mesmo, difundido pela mídia gestada a partir da lógica da Indústria Cultural. Assim sendo, o objetivo deste texto é analisar a partir das capas da Revista Playboy de 2012, como a Indústria Cultural dissemina um modelo de saúde e beleza, tanto para homens como para mulheres. Como metodologia, adotamos a análise documental dos doze números desta revista que foi publicado em 2012. Os dados mostram que as modelos das capas são brancas, predominantemente jovens e com cabelos loiros e, com níveis de Índice de Massa Corporal (IMC) de uma pessoa magra. A conclusão demonstra que a Revista Playboy, contribui para a disseminação de um modelo de corpo considerado em sua aparência, belo e saudável.

O presente artigo tem como objetivo analisar as dificuldades e rumos da criação de um Estado palestino e seus impactos para a consolidação da paz no oriente médio.

Anglés y Subirá, Sign.: [ ]⁴, a-e⁸, f⁶

Anglés y Subirá, Sign.: [ ]⁴, a-e⁸, f⁶