6 research outputs found
New sensitivity analysis attack
No full textThe sensitivity analysis attacks by Kalker et al. constitute a known family of watermark removal attacks exploiting a vulnerability in some watermarking protocols: the attacker’s unlimited access to the watermark detector. In this paper, a new attack on spread spectrum schemes is designed. We first examine one of Kalker’s algorithms and prove its convergence using the law of large numbers, which gives more insight into the problem. Next, a new algorithm is presented and compared to existing ones. Various detection algorithms are considered including correlation detectors and normalized correlation detectors, as well as other, more complicated algorithms. Our algorithm is noniterative and requires at most n + 1 operations, where n is the dimension of the signal. Moreover, the new approach directly estimates the watermark by exploiting the simple geometry of the detection boundary and the information leaked by the detector
Novel algorithms for sensitivity analysis attacks
No full textSensitivity analysis attacks constitute a powerful family of watermark “removal ” attacks. They exploit a vulnerability in some watermarking protocols: the attacker’s unlimited access to the watermark detector. This paper proposes a mathematical framework for designing sensitivity analysis attacks and focuses on additive spread spectrum embedding schemes. The detectors under attack range in complexity from basic correlation detectors to normalized correlation detectors and maximum likelihood (ML) detectors. The new algorithms precisely estimate and then eliminate the watermark from the watermarked signal. This is done by exploiting geometric properties of the detection boundary and the information leaked by the detector. Several important extensions are presented, including the case of a partially unknown detection function, and the case of constrained detector inputs. In contrast with previous art, our algorithms are noniterative and require at most O(n) detection operations in order to estimate the watermark, where n is the dimension of the signal. The cost of each detection operation is O(n), hence the algorithms can be executed in quadratic time. The method is illustrated with an application to image watermarking using an ML detector based on a generalized Gaussian model for images
related metabolic cutis laxa
No full textSeveral inborn errors of metabolism show cutis laxa as a highly recognizable feature. One group of these metabolic cutis laxa conditions is autosomal recessive cutis laxa type 2 caused by defects in v-ATPase components or the mitochondrial proline cycle. Besides cutis laxa, muscular hypotonia and cardiac abnormalities are hallmarks of autosomal recessive cutis laxa type 2D (ARCL2D) due to pathogenic variants in ATP6V1A encoding subunit A of the v-ATPase. Here, we report on three affected individuals from two families with ARCL2D in whom we performed whole exome and Sanger sequencing. We performed functional studies in fibroblasts from one individual, summarized all known probands' clinical, molecular, and biochemical features and compared them, also to other metabolic forms of cutis laxa. We identified novel missense and the first nonsense variant strongly affecting ATP6V1A expression. All six ARCL2D affected individuals show equally severe cutis laxa and dysmorphism at birth. While for one no information was available, two died in infancy and three are now adolescents with mild or absent intellectual disability. Muscular weakness, ptosis, contractures, and elevated muscle enzymes indicated a persistent myopathy. In cellular studies, a fragmented Golgi compartment, a delayed Brefeldin A-induced retrograde transport and glycosylation abnormalities were present in fibroblasts from two individuals. This is the second and confirmatory report on pathogenic variants in ATP6V1A as the cause of this extremely rare condition and the first to describe a nonsense allele. Our data highlight the tremendous clinical variability of ATP6V1A related phenotypes even within the same family
Located Lexicon: a project that explores how user generated content describes place
No full textThis extended conference paper explores the use and potential of location data in social media contexts. The research involved a series of experiments undertaken to assess the extent to which location information is present in exchanges, directly or indirectly. A prototype application was designed to exploit the insight obtained from the data-gathering experiments. This enabled us to develop a method and toolkit for searching, extracting and visualising mass-generated data for open source use. Ultimately, we were able to generate insights into data quality and ‘scale of query’ for emerging pedagogical research in learning swarms and distributed learners
Alternative splicing of BUD13 determines the severity of a developmental disorder with lipodystrophy and progeroid features
No full textPurpose: In this study we aimed to identify the molecular genetic cause of a progressive multisystem disease with prominent lipodystrophy. Methods: In total, 5 affected individuals were investigated using exome sequencing. Dermal fibroblasts were characterized using RNA sequencing, proteomics, immunoblotting, immunostaining, and electron microscopy. Subcellular localization and rescue studies were performed. Results: We identified a lipodystrophy phenotype with a typical facial appearance, corneal clouding, achalasia, progressive hearing loss, and variable severity. Although 3 individuals showed stunted growth, intellectual disability, and died within the first decade of life (A1, A2, and A3), 2 are adults with normal intellectual development (A4 and A5). All individuals harbored an identical homozygous nonsense variant affecting the retention and splicing complex component BUD13. The nucleotide substitution caused alternative splicing of BUD13 leading to a stable truncated protein whose expression positively correlated with disease expression and life expectancy. In dermal fibroblasts, we found elevated intron retention, a global reduction of spliceosomal proteins, and nuclei with multiple invaginations, which were more pronounced in A1, A2, and A3. Overexpression of both BUD13 isoforms normalized the nuclear morphology. Conclusion: Our results define a hitherto unknown syndrome and show that the alternative splice product converts a loss-of-function into a hypomorphic allele, thereby probably determining the severity of the disease and the survival of affected individuals
Augmented reality and tourism: a bibliometric analysis of new technological bets in the Post-COVID era
No full textTourism is a sector of high relevance worldwide, due to the multiple impacts it generates in local, regional, national, continental, and global economies, and it is a key generator of employment and provides sustenance to an innumerable number of people around the world. There have been many challenges at a global level to improve the user experience in a particular tourist place, where technology has played a highly relevant role in strengthening the conditions for tourists to achieve immersion in the culture, gastronomy, and recreation. The objective of this literature review is precisely to know and understand the key contributions that are currently being developed around the implementation of augmented reality as tourist technological support for user experiences. The literature on this topic is quite dispersed in specialized databases; therefore, it constitutes an opportunity to carry out a more detailed exploration of the topic. To address the different developments that have been carried out on tourism and augmented reality, an analysis was carried out based on the fusion of scientometric analysis and the metaphor of the Tree of Science, in which two relevant visions about the data were generated. The first focused on the different scientometric statistics regarding countries, authors, universities, or research or technological development centers that currently generate new applications based on augmented reality for tourism. The second focused on an evolutionary analysis based on the Tree of Science, analyzing the origins of the basic contributions of research and how it has evolved over time. This review indicates that the topic is currently valid and that it has been strengthened even more with the post-pandemic process, where many technological developments have been strengthened that allow people to enjoy tourist and cultural sites even without leaving home
