Fast, parallel and secure cryptography algorithm using Lorenz's attractor

A novel cryptography method based on the Lorenz's attractor chaotic system is presented. The proposed algorithm is secure and fast, making it practical for general use. We introduce the chaotic operation mode, which provides an interaction among the password, message and a chaotic system. It ensures that the algorithm yields a secure codification, even if the nature of the chaotic system is known. The algorithm has been implemented in two versions: one sequential and slow and the other, parallel and fast. Our algorithm assures the integrity of the ciphertext (we know if it has been altered, which is not assured by traditional algorithms) and consequently its authenticity. Numerical experiments are presented, discussed and show the behavior of the method in terms of security and performance. The fast version of the algorithm has a performance comparable to AES, a popular cryptography program used commercially nowadays, but it is more secure, which makes it immediately suitable for general purpose cryptography applications. An internet page has been set up, which enables the readers to test the algorithm and also to try to break into the cipher in

La imagen postmortem y el rito de los invitados: Un análisis de la escopía de la despedida

Es una buena descripción de la forma tradicional en la que regionalmente se organiza la ritualidad hacia la muerte, con un importante contenido analítico en torno a la cuestión de la muerte, desde la antropología y el psicoanálisis, principalmente como transdisciplinariedad con la que traban los estudios visuales.Es un trabajo terminal de grado en el cual se aborda la fotografía postmortem como una práctica que se mantiene socialmente, y que incluye actividades y formas de asumir el procesamiento de la pérdida en su relación con el manejo de las imágenes fotográficas

Fundamental Finite Key Limits for One-Way Information Reconciliation in Quantum Key Distribution

The security of quantum key distribution protocols is guaranteed by the laws of quantum mechanics. However, a precise analysis of the security properties requires tools from both classical cryptography and information theory. Here, we employ recent results in non-asymptotic classical information theory to show that one-way information reconciliation imposes fundamental limitations on the amount of secret key that can be extracted in the finite key regime. In particular, we find that an often used approximation for the information leakage during information reconciliation is not generally valid. We propose an improved approximation that takes into account finite key effects and numerically test it against codes for two probability distributions, that we call binary-binary and binary-Gaussian, that typically appear in quantum key distribution protocols

Development of a sensory substitution API

2018 Summer.Includes bibliographical references.Sensory substitution – or the practice of mapping information from one sensory modality to another – has been shown to be a viable technique for non-invasive sensory replacement and augmentation. With the rise in popularity, ubiquity, and capability of mobile devices and wearable electronics, sensory substitution research has seen a resurgence in recent years. Due to the standard features of mobile/wearable electronics such as Bluetooth, multicore processing, and audio recording, these devices can be used to drive sensory substitution systems. Therefore, there exists a need for a flexible, extensible software package capable of performing the required real-time data processing for sensory substitution, on modern mobile devices. The primary contribution of this thesis is the development and release of an Open Source Application Programming Interface (API) capable of managing an audio stream from the source of sound to a sensory stimulus interface on the body. The API (named Tactile Waves) is written in the Java programming language and packaged as both a Java library (JAR) and Android library (AAR). The development and design of the library is presented, and its primary functions are explained. Implementation details for each primary function are discussed. Performance evaluation of all processing routines is performed to ensure real-time capability, and the results are summarized. Finally, future improvements to the library and additional applications of sensory substitution are proposed

Optimal Control for Management in Gypsy Moth Models

The gypsy moth, Lymantria dispar (L.), is an invasive species and the most destructive forest defoliator in North America. Gypsy moth outbreaks are spatially synchronized over areas across hundreds of kilometers. Outbreaks can result in loss of timber and other forestry products. Greater losses tend to occur to the ecosystem services that forests provide, such as wildlife habitat, carbon sequestration, and nutrient cycling. The United States can be divided in three different areas: a generally infested area (populations established), an uninfested area (populations not established), and a transition zone between the two. There are different management programs matching these different areas: detection and eradication, the Slow-the-Spread program, and suppression of outbreaks in areas that are infested by the gypsy moth as a means to mitigate impacts. This dissertation focuses in optimal control techniques for models of areas where the population is established or in the invasion front. We develop an optimal control formulation for models of an established population of the invasive pest gypsy moth. The models include interaction with a pathogen and a generalist predator. The population of gypsy moth is assumed to be controlled with the pesticide Bt. The assumed objective functional minimizes cost due to gypsy moth and cost for suppressing the population of gypsy moth. Optimization techniques in our numerical results, suggest the timing and intensity of control. Our results are consistent over different parameter values and initial conditions. To model the population in the invasion front, we develop the theory of optimal control for a system of integrodifference equations. Integrodifference equations incorporate continuous space into a system of discrete time equations. We design an objective functional to minimize the cost generated by the defoliation caused by the gypsy moth and the cost of controlling the population. Existence and uniqueness results for the optimal control and corresponding states have been completed. We use a forward-backward sweep numerical method, and our numerical results suggest appropriate spatial and temporal location and intensity of optimal controls

Characterization of Heavy Hydrocarbon Contaminated Soils Remediated by Thermal Methods

There are numerous opportunities in the lifecycle of oil extraction, transport, and use where it can potentially contaminate the environment, in particular water and soil. Various technologies have been developed to remediate soil contamination; the techniques can be categorized as either energetic, where energy is required for treatment, or non-energetic, requiring no additional energy input. Previous studies have determined that energetic methods tend to be more effective at reducing total petroleum hydrocarbons (TPH). In particular, thermal desorption was found to remove hydrocarbons in the target molecular size range of hydrocarbon species up to C₄₀, while leaving beneficial carbon content, such as soil organics, intact. The goal of this study was the characterization of soil treated with energetic remediation methods. Specifically, soils treated by indirect thermal desorption (inert environment) or directly heated thermal desorption (heated by products of combustion, including oxygen) were characterized to determine their efficacy and investigate the underlying mechanisms. Temperature programmed reaction experiments (including oxidation and desorption) were used to measure the relative amounts of total, mobile, and fixed carbon content remaining on the treated soil. For the indirect thermal desorption, total carbon content was found to reduce proportionately with decreases in initial oil concentration and only marginally with increases in either treatment temperature or residence time. The minimum time and temperature values (15 minutes and 370°C, respectively) were found to adequately reduce total carbon and, by extension, TPH. Further increases in residence time or treatment temperature would increase treatment costs for insubstantial gains. Increased temperature and decreased oil concentration both decreased total carbon for the direct heated thermal desorption treatment. In contrast to the indirect treatment, total carbon reduction in the direct treatment appeared to be a stronger function of temperature, with total carbon content for the maximum temperature being a quarter of that at the minimum. Initial oil concentration appeared to be normalized to some extent by the direct treatment, with respective carbon content levels approaching each other. It was again determined that the minimum energy input treatments characterized herein would sufficiently reduce TPH. For a 15 minute residence time and 420°C treatment temperature, the indirect treatment was found to have produced a larger carbon content reduction than the direct treatment. The Boudouard reaction is a proposed explanation for this result on the basis of entrance and exit gas flow compositions, as well as the increased fixed carbon found on the direct treated soil