446 research outputs found
A Moral Revolution at Mazorra, 1899–1902
No full textChapter 1 examines the massive reconstruction effort undertaken at Mazorra at the end of the Cuban independence war. In particular, it examines the collaboration between U.S. occupying forces and Cuban liberating hero Lucas Álvarez Cerice to transform popular outrage over asylum conditions into a popular and patriotic rebuilding effort. Both groups turned Mazorra into a key nationalist icon, even as their efforts to implement a new therapeutic regimen (with particular emphasis on work as treatment) recapitulated racial and class divides.</p
Fragments of a Journey to Mazorra
No full textChapter 2 follows the unlikely pact between U.S. occupying forces and patriotic doctors through its fraying under the auspices of Cuba’s first sovereign government (1902-6) and its revival during another U.S. occupation (1906-9). As public alarm grew over a ballooning institutional population and patient death rate, Mazorra’s status as an icon of a sovereign Cuba increasingly cast doubts on the political health of that nation. Reformers, doctors, and patients all contributed to the project of unpacking what sovereignty would mean for Mazorra and Cuba.</p
Mathematical Models for the Calibration of Cameras Mounted on a Tripod Using Primitive Tracking
No full textIn this paper we present new mathematical models for video sequence calibration when cameras are mounted on a tripod. One of the main novelties is that tripod rotation center and camera projection center are not supposed to be the same. The calibration is based on the geometry of the tripod and a primitive tracking procedure which uses lines and circles as primitives. For the extraction of primitive information, we use a CART (Classification and Regression Tree). We have applied the method proposed to sport event scenarios, specifically, soccer matches. In order to illustrate its performance, it has been applied to real HD (High Definition) video sequences and some numerical experiments are shown. The quality of the camera calibration procedure is validated by inserting virtual elements in the video sequence.3113040,323Q
Signal and image restoration using shock filters and anisotropic diffusion
No full textThe authors define a new class of filters for noise elimination and edge enhancement by using shock filters and anisotropic diffusion. Some nonlinear partial differential equations used as models for these filters are studied. The authors develop recursive and unconditional stable schemes which drastically reduce the computational effort of the algorithms. A new fast recursive approach to linear Gaussian filters is also shown by using the heat equation.605590SCI
Fitting ear contour using an ovoid model
No full textEar analysis is an emergent biometric application. The main advantages are the no requirement for subject contact and acquisition without demand. To recognize a subject's ear, we aim to extract a characteristic vector from a human ear image that may subsequently be used to identify or confirm the identity of the owner. Towards this end, a new technique, combining geodesic active contours and a new ovoid model, has been developed, which can be used to compare ears in an independent way of the ear location and size.14814
A formal introduction to zero-knowledge proofs
No full textTreballs Finals de Grau de Matemàtiques, Facultat de Matemàtiques, Universitat de Barcelona, Any: 2024, Director: Bruno Mazorra i Luis Victor DieulefaitThe idea of zero-knowledge proof was first introduced by Goldwasser, Micali and Rackoff [GMR89] and has found its way to many real-world applications. The growing need for privacy in information exchange (e.g. transactions, digital signatures, commitment schemes, ...) lead to the development of proofs that yield nothing more than their validity.
We introduce the building blocks for zero-knowledge proofs through mathematical rigour, allowing the reader to gain a solid foundation to research further related topics. We explore some necessary notions of cryptography and probability, as well as computation theory by utilizing Turing machines as an automation abstraction. We delve into the theory of decision problems and the consequent classification through complexity classes, specially and . We use the concepts of repetition and interaction to prove that the decision error for languages in and can be decreased exponentially and explore the example of Graph Non-Isomorphism. We introduce the idea of zero-knowledge interactive proof systems and define some variations of its definition. We explore the example of Graph Isomorphism and conclude showing that the sequential repetition of zero-knowledge interactive proofs is indeed a zero-knowledge interactive proof
A formal introduction to zero-knowledge proofs
No full textTreballs Finals de Grau de Matemàtiques, Facultat de Matemàtiques, Universitat de Barcelona, Any: 2024, Director: Bruno Mazorra i Luis Victor DieulefaitThe idea of zero-knowledge proof was first introduced by Goldwasser, Micali and Rackoff [GMR89] and has found its way to many real-world applications. The growing need for privacy in information exchange (e.g. transactions, digital signatures, commitment schemes, ...) lead to the development of proofs that yield nothing more than their validity.
We introduce the building blocks for zero-knowledge proofs through mathematical rigour, allowing the reader to gain a solid foundation to research further related topics. We explore some necessary notions of cryptography and probability, as well as computation theory by utilizing Turing machines as an automation abstraction. We delve into the theory of decision problems and the consequent classification through complexity classes, specially and . We use the concepts of repetition and interaction to prove that the decision error for languages in and can be decreased exponentially and explore the example of Graph Non-Isomorphism. We introduce the idea of zero-knowledge interactive proof systems and define some variations of its definition. We explore the example of Graph Isomorphism and conclude showing that the sequential repetition of zero-knowledge interactive proofs is indeed a zero-knowledge interactive proof
Geographies of Globality, Individuality, and Morality
No full textThe Ebook version was published in 2025.From the tradition of human and rural geography, the author analyzed the current limitation of the geographical debates to study the global processes of rural transformation to key – meso – areas in Global North and Global South. The case studies are mainly associated with the key ideas of Anglo-American discussion and the Latin-American debate. Additionally, examples from other geographical areas are used to describe large processes of individuality and transformation as rural gentrification, feminism/woman, and rural diasporas.
Currently, there is a revitalization of globality in rural studies, but it largely revitalizes old analytical trends from the political economy that associate large global transformation processes with local manifestations – facts.
Based on the geographical minor theory of everyday life, an alternative approach is proposed that connects the individual with global processes even within each locality (community). This point of view is based on the minor positionality of an individual on the global processes of transformation, as opposed to the usual domain in geographical studies that locality/community associates with globality.
The individual (re)articulates the spatial, social, and economic geographical processes around the individual citizen who moves through a globalized and global space. Places are permanently rearticulated, even on a daily basis, in a permanent negotiation of daily life between opposite (or not) interests of individuals. The spaces of life and activity are the confluence and coexistence of multiple live paths. These multiple paths move in spaces that are dominated by certain characteristic postmodern processes.
This approach enables a moral look at the global transformation processes founded on the individual. It also promotes a single analytical framework for possible situations of the (rural) individual in the global transformation processes.Peer reviewe
Daily global solar radiation modeling for Gran Canaria Island
No full textThe main aim of this paper is the daily global solar radiation modeling with different estimation models for the island of Gran Canaria (Spain). The errors of those ones will be studied and, moreover, the results will be compared with a solar radiation numerical model previously developed and validated. We have tested five different models starting from the Ångström linear model. Logarithmic, exponential, cubic models, and an exponential-linear composed model have been developed. The best results were obtained with the composed model. The development of these models will allow getting accurate results far from the measurements stations.356435570,2890,527Q2Q4SCI
Normalization and feature extraction on ear images
No full textEar image analysis is an emerging biometrie application. A method for normalizing ear images and extracting from them a set of measurable features (feature vector) that can be used to identify its owner is proposed. The identification would be made based on the comparison between the feature vector of the input image and all feature vectors of the images in the database we work with. The feature vector is based on the ear contours. One important goal of this paper is to identify the most significant areas in the ear contour for human being identification purpose. Another important contribution of the paper is the combination of active contours techniques and ovoid model ear fitting (used to normalize ear features) and a high accurate invariant approach of internal and external ear contours. Ear geometry is characterized using a set of distances to external and internal contours points. This set of distances, along with six ovoid parameters is considered as the feature vector of the image. To test the method a new ear images database has been created. The proposed method identifies front-parallel views pretty good, even when varying the distance of the individual to the camera or the camera lens.1049
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